Alterations of the p53 gene in human primary cervical carcinoma with and without human papillomavirus infection. A previous report using cervical carcinoma cell lines suggests that the inactivation of two tumor suppressor gene products, p53 and pRB, either by complex formation with the E6 and E7 proteins of oncogenic human papillomaviruses (HPVs) or by mutation, may be an important step in cervical carcinogenesis (M. Scheffner et al., Proc. Natl. Acad. Sci. USA, 88: 5523-5527, 1991). The present study was designed to clarify the association between p53 inactivation and infection with oncogenic HPVs in primary carcinomas of human uterine cervix. We examined 36 primary cervical carcinomas for the presence of HPV DNAs by Southern blot analysis with probes specific for HPV-16, -18, -31, -33, -52, -56, and -58. HPV DNA sequences were detected in 19 of 36 tumors: 10 cases with HPV-16; 3 cases with -18; 3 cases with -58; 2 cases with -56; and one case with -52. The presence of HPV-16 and -18 in cervical carcinomas was further reexamined using polymerase chain reaction. HPV DNA sequences were detected in an additional 10 cases: 9 cases with -16 and one case with -18. The inactivation of the p53 gene by allelic loss or by point mutation was also examined. No allelic loss at the polymorphic site in codon 72 of the p53 gene was detected in any of 10 informative cases. Missense point mutations in the highly conserved regions of the p53 gene were demonstrable as single-stranded conformational polymorphisms of polymerase chain reaction-amplified DNA fragments and subsequently identified by direct DNA sequencing. Point mutations were detected in only two cases: one with an ATG----CTG transversion in codon 133 of exon 5, resulting in a Met----Leu substitution, and another with a CGG----TGG transition in codon 248 of exon 7, resulting in an Arg----Trp substitution. Both tumors with point mutations in p53 genes were among 10 tumors which contained a small copy number of HPV-16 DNA sequences (1 copy of HPV/10(1) to 10(5) cells) detectable by polymerase chain reaction amplification but not by Southern blot analysis of genomic DNAs derived from the tumors. None of 19 tumors with a large copy number of HPV DNA sequences detectable by Southern blot analysis (more than 1 copy of HPV/2 to 10 cells) nor any of 7 tumors with undetectable HPV DNA sequences contained p53 gene mutations in the regions examined.(ABSTRACT TRUNCATED AT 400 WORDS)


Steady-state messenger RNA and activity correlates with sensitivity to N1,N12-bis(ethyl)spermine in human cell lines representing the major forms of lung cancer. Our previous results from a limited number of cell lines have suggested that the bis(ethyl)polyamine analogues exert a phenotype-specific response in human lung cancer cells. In the present study, we have extended this work to analyze the response of the 4 major forms of human lung cancer to the polyamine analogue N1,N12-bis(ethyl)spermine (BESpm). The results suggest that non-small cell phenotypes are much more sensitive to the cytotoxic effects of BESpm than the small cell lung carcinoma phenotype. Further, there appears to be a positive association between the level of induction of the polyamine catabolic enzyme spermidine/spermine N1-acetyltransferase (SSAT) in response to the analogue and the kinetic response of cells. Specifically, cells in which SSAT activity is highly induced by BESpm are killed by the compound. Although induction of SSAT appears to occur at both the level of increased steady-state mRNA and enzyme activity, SSAT activity appears to be a better indicator of cell sensitivity to BESpm than SSAT mRNA levels. These results have significance both for the potential use of polyamine analogues in treating specific forms of human lung cancer and for understanding the regulation of SSAT at the molecular level.


Primary immunodeficiencies: genetic risk factors for lymphoma. It has been estimated that up to 25% of patients with certain genetically determined immunodeficiencies will develop tumors, primarily B-cell lymphomas, during their lifetime. Epstein-Barr virus appears to be an important cofactor in the development of lymphoproliferative disorders in patients with primary immunodeficiencies, as well as acquired immunodeficiencies. Additionally, host defects in immunoregulation and/or gene rearrangement, which are features of certain primary immunodeficiencies, probably contribute to the risk of lymphomagenesis in patients at risk.


Epidemiological and biological study of acquired immunodeficiency syndrome-related lymphoma in the County of Los Angeles: preliminary results. A population-based case control study of intermediate- and high-grade lymphoma in the County of Los Angeles, CA, was initiated in 1989. Human immunodeficiency virus (HIV)-positive lymphoma patients are compared to HIV-negative lymphoma patients, to HIV-positive controls with acquired immunodeficiency syndrome but without lymphoma, and to HIV-positive asymptomatic individuals. The HIV-negative lymphoma cases are compared to neighborhood controls, who are matched in terms of age, sex, race/ethnicity, and socioeconomic status. All cases are reviewed for pathology by a single group of pathologists. All cases and controls are studied for HIV, Epstein-Barr virus (EBV), and human herpesvirus 6 antigens and antibodies. Tissues from HIV-positive and -negative cases are studied for immunoglobulin gene rearrangement, presence of EBV and HIV, c-myc oncogene rearrangements, and karyotypic analysis. To date, with 294 lymphoma cases and 181 control cases interviewed, high-grade lymphoma has been diagnosed in 82% of the HIV-positive cases versus 40% of the HIV-negative cases (P = 0.001). Although elevated titers of EBV-viral capsid antigen were demonstrated in 82% of HIV-positive versus 50% of HIV-negative lymphoma cases, the geometric mean titer of EBV-viral capsid antigen is similar among HIV-positive lymphoma cases and HIV-positive controls. The geometric mean titer of human herpesvirus 6 antibodies was similar in HIV-positive and HIV-negative lymphoma cases and in the control populations. Monoclonality was demonstrated in all cases of lymphoma. EBV genome was demonstrated within lymphoma DNA in 68% of HIV-positive and 15% of HIV-negative lymphoma cases. Further study will be required to elucidate the full mechanisms of pathogenesis of the acquired immunodeficiency syndrome-related lymphomas.


Epstein-Barr virus-induced human B-cell lymphomas in SCID mice reconstituted with human peripheral blood leukocytes. Epstein-Barr virus (EBV) infection is associated with immunoblastic B-cell lymphomas in immunosuppressed or human immunodeficiency virus-infected individuals and in SCID mice reconstituted with human peripheral blood leukocytes (hu-PBL-SCID) from EBV-seropositive donors. The risk of tumors appearing in the hu-PBL-SCID mice differs among EBV-seropositive donors. Four different outcomes have been noted: (a) no tumors appear (no incidence donors); (b) tumors appear in a fraction of hu-PBL-SCID mice with a 10-20 week latent period (low- and intermediate-incidence donors); or (c) tumors appear in all hu-PBL-SCID mice within 6-10 weeks (high-incidence donors). The latter category of rapidly appearing tumor invariably involved activation of EBV replication, whereas more slowly growing tumors rarely activated EBV. The results indicate that prospective screening of high-risk individuals in the hu-PBL-SCID model may predict the risk of EBV-associated lymphoma development.


Loss of the metastatic phenotype by a human epidermoid carcinoma cell line, HEp-3, is accompanied by increased expression of tissue inhibitor of metalloproteinase 2. The human epidermoid carcinoma cell line HEp-3 gives rise to spontaneous metastases in nude mice and in the chick chorioallantoic membrane (CAM) assay system. Cells passaged continuously on the CAM retain their ability to form metastases, while cells carried in vitro lose metastatic potential with time. A HEp-3 cell line derived from a highly metastatic CAM tumor was grown continuously in vitro for 16 weeks. At 2-week intervals the cells were tested on the CAM for metastatic ability and assayed for expression of urokinase-type plasminogen activator (uPA) and the M(r) 92,000 and M(r) 72,000 gelatinase/type IV collagenases, enzymes the expression of which has previously been shown to correlate with tumor cell dissemination. Expression of proteins which modulate the degradative potential of these enzymes, plasminogen activator inhibitors 1 and 2 (PAI-1, PAI-2), uPA receptor, and tissue inhibitors of metalloproteases 1 and 2 (TIMP-1 and TIMP-2), were also assayed. As previously reported the metastatic ability of these cells decreased with time in culture and was almost completely lost by 8 weeks in vitro. Secreted uPA activity remained essentially unchanged, even though uPA mRNA levels decreased with time. There was also a decrease in PAI-1 and PAI-2 mRNA. However, PAI-1 protein concentration in conditioned medium remained relatively constant, and only trace amounts of PAI-2 protein could be detected in cell lysates. Steady-state levels of uPA receptor were lowest at 2 weeks then increased sharply at 4 weeks and remained relatively constant thereafter. A decrease in secreted M(r) 92,000 and M(r) 72,000 gelatinase activities and their corresponding mRNAs was observed well after the loss of the metastatic phenotype. During the 16 weeks in culture TIMP-1 mRNA levels changed slightly, while TIMP-2 mRNA increased more than 2-fold. These data suggest that a metalloproteinase other than the gelatinase/type IV collagenases may be involved in HEp-3 metastasis.


Particular types of tumor cells have the capacity to convert transforming growth factor beta from a latent to an active form. We investigated the capacities of various tumor types to generate an active versus latent form of transforming growth factor beta (TGF-beta) in its culture supernatants (SNs). Tumor cell lines were divided into three types depending on the form and magnitude of TGF-beta detected in their culture SNs: some (2 of 7 lines) generated mostly an active form (Type A); others (4 of 7) generated exclusively a latent form (Type B); and the remaining line (1 of 7) produced only marginal levels of active/latent TGF-beta (Type C). When Type A tumor cells were cultured at lower numbers, cultures failed to generate active TGF-beta. However, the addition of Type B tumor cell culture SNs containing only a latent form of TGF-beta resulted in the generation of the potent activity of active TGF-beta. This capacity was observed for another Type A tumor but not for other types (Type B and Type C). An active form of TGF-beta was detected in culture SNs of Type A tumor cells as early as 3-6 h after the addition of Type B tumor culture SNs. The emergence of an active form of TGF-beta was also observed in cultures of Type A tumor cells, the protein synthesis of which was almost completely inhibited by pretreatment with cycloheximide. Moreover, the Type B tumor SN used for the induction of active TGF-beta activity was found to contain latent TGF-beta with an apparent molecular weight of about 200,000. Type A tumor cells were also capable of generating active TGF-beta by the addition of recombinant TGF-beta of latent form with a small molecular weight (about 60,000), although the generation of active TGF-beta was much weaker after the addition of small latent TGF-beta than after the addition of large latent TGF-beta. Taken collectively, these results indicate that particular types of tumor cells have the capacity to generate an active form of TGF-beta and that such capacity can be attributed to their potential to convert TGF-beta from a latent (mainly large type) to an active form.


Sensitivity to novel platinum compounds of panels of human lung cancer cell lines with acquired and inherent resistance to cisplatin. We have developed panels of human lung cancer cell lines with acquired and inherent resistance to cisplatin. Three parental cell lines, NCI-H69/P (small cell), COR-L23/P (large cell), and MOR/P (adenocarcinoma), were grown in increasing concentrations of cisplatin over a period of 6-9 months. This resulted in the development of sublines, H69/CPR, L23/CPR, and MOR/CPR which were 3- to 8-fold resistant to cisplatin as determined by a 6-day 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. None of the resistant sublines showed a significant change in cellular glutathione content or sensitivity to cadmium chloride (an indicator of metallothionein content), although changes in glutathione-S-transferase activity were seen. The sublines each showed cross-resistance to melphalan. Cisplatin accumulation was unchanged in H69/CPR, 1.3-fold reduced in L23/CPR, and 2.0-fold reduced in MOR/CPR compared with their respective parent lines. In a panel of 10 small cell lung cancer cell lines, there was a 16-fold range of sensitivities to cisplatin. The panels have been used to examine cross-resistance between cisplatin, carboplatin, iproplatin, tetraplatin, and a series of 10 novel ammine/amine dicarboxylate platinum(IV) compounds. Whereas H69/CPR and MOR/CPR showed little or no cross-resistance to any of the other compounds, L23/CPR was generally cross-resistant to all of them. In the panel of small cell lines, whereas the ranking of sensitivity to carboplatin and cisplatin were similar, each of the other compounds provided individual patterns of sensitivity. There was always a wide range of sensitivities among the panel, ranging from 8- to 28-fold. Among the dicarboxylate compounds, there was a great range of potencies, with two compounds (JM273 and JM274) being approximately 100-fold more potent than cisplatin.


Carotenoids up-regulate connexin43 gene expression independent of their provitamin A or antioxidant properties. Epidemiological evidence and studies in whole animals and cell culture have indicated that carotenoids have cancer chemopreventive action. In mouse C3H10T1/2 cells, this activity is highly correlated with the ability of carotenoids to up-regulate gap junctional intercellular communication. Here, we report that in mouse cells, carotenoids increase the expression of connexin43, a gene that encodes a major gap junction protein. This effect appears unrelated to their provitamin A or antioxidant properties, since carotenoids with and without provitamin A activity increased levels of connexin43 mRNA and protein, whereas the antioxidants methyl-bixin and alpha-tocopherol were inactive. Moreover, the active carotenoid canthaxanthin did not induce the vitamin A-inducible gene retinoic acid receptor-beta. Connexin43 is the first carotenoid-inducible gene described in mammals. By indicating an additional pathway through which carotenoids function, these data provide a mechanistic basis for cancer chemoprevention by carotenoids and may lead to a re-evaluation of carotenoid physiology.


FLT4 receptor tyrosine kinase contains seven immunoglobulin-like loops and is expressed in multiple human tissues and cell lines. The fms-like tyrosine kinase 4 (FLT4) complementary DNA was cloned from a human HEL erythroleukemia cell library by polymerase chain reaction-amplification. We previously reported a partial sequence of FLT4 and showed that the FLT4 gene maps to chromosomal region 5q33-qter (O. Aprelikova, K. Pajusola, J. Partanen, E. Armstrong, R. Alitalo, S. Bailey, J. McMahon, J. Wasmuth, K. Huebner, and K. Alitalo, Cancer Res., 52: 746-748, 1992). Here we present the full-length sequence of the predicted FLT4 protein. The extracellular domain of FLT4 consists of 7 immunoglobulin-like loops, including 12 potential glycosylation sites. On the basis of structural similarities FLT4 and the previously known FLT1 and kinase insert domain-containing receptor tyrosine kinase/fetal liver kinase 1 (KDR/FLK1) receptors constitute a subfamily of class III tyrosine kinases. FLT4 was expressed as 5.8- and 4.5-kilobase mRNAs which were found to differ in their 3' sequences and to be differentially expressed in the HEL and DAMI leukemia cells. Interestingly, a Wilms' tumor cell line, a retinoblastoma cell line, and a nondifferentiated teratocarcinoma cell line expressed FLT4, whereas differentiated teratocarcinoma cells were negative. Most fetal tissues also expressed the FLT4 mRNA, with spleen, brain intermediate zone, and lung showing the highest levels. In in situ hybridization the FLT4 autoradiographic grains decorated bronchial epithelial cells of fetal lung. No evidence was obtained for the expression of FLT4 in the endothelial cells of blood vessels.


Genomic rearrangements in mouse C3H/10T1/2 cells transformed by X-rays, UV-C, and 3-methylcholanthrene, detected by a DNA fingerprint assay. Genomic rearrangements occurring in C3H/10T1/2 cells transformed by X-rays were examined with a DNA fingerprint assay. Four multilocus and multiallele probes were employed (M, X, H10, and H16) that detect different families of minisatellite sequences dispersed throughout the genome. Genomic rearrangements were detectable only with probe M. This specificity may be explained by a genomic instability owing to a specific sequence or structure of DNA recognized by probe M. Genomic rearrangements were detected in 5 of 12 type III foci transformed by 600 cGy of X-rays and in all clones isolated from a previously transformed clone exposed to a second dose of 600 cGy and recloned. The latter data suggest that the stage of transformation and the occurrence of genomic rearrangement induced by X-rays may be related. An intensity shift or a complete deletion of band 2 was common to these X-ray-induced clones, as well as to clones transformed by UV-C (1 of 5) or 3-methylcholanthrene (4 of 6). This band did not hybridize to probes for the retinoblastoma gene RB or for p53. We hypothesize that the loss of band 2 may reflect a significant genetic change in the transformation of 10T1/2 cells, perhaps representing the inactivation of a tumor suppressor gene other than RB or p53. Additional rearrangements occurred in X-ray-transformed clones; these rearrangements were not observed with the other carcinogens. Aside from the changes in band 2, however, no specific pattern of genomic rearrangement was associated with X-ray transformation, and the presence or absence of rearrangements did not correlate with tumorigenicity in syngeneic nonimmunosuppressed C3H mice.


Antitumor activity of the type 1 plasminogen activator inhibitor and cytotoxic conjugate in vitro. Many cancer cell lines and cancers overexpress receptor bound urokinase plasminogen activator on the cell surface. The urokinase plasminogen activator bound to its receptor remains on the cell surface for a prolonged period of time. When urokinase plasminogen activator/urokinase plasminogen activator receptor complex binds plasminogen activator inhibitor (PAI-1), the inhibitor triggers a series of events leading to internalization of the entire complex. This mechanism makes a very attractive target for localization and internalization of PAI-1-based cytotoxic compounds in cancer treatment. We investigated the antitumor activity of PAI-1/A-chain cholera toxin in vitro. Fibrosarcoma-derived HT1080 cells treated with PAI-1 conjugate showed at least 4 times higher cell killing than the control KD normal fibroblast cell line.


Cellular transformation by a unique isolate of human papillomavirus type 11. Infection with human papillomavirus type 11 (HPV 11) is associated with benign epithelial proliferations and rarely with malignant and metastasizing tumors. Because of the biological diversity displayed in tissues infected with HPV 11, we have examined the capacity of various isolates of HPV 11 to transform cultured cells and compared their molecular differences by DNA sequence analysis. Five isolates of HPV 11 were examined for their ability to transform primary neonatal rat kidney epithelial cells and NIH 3T3 mouse fibroblasts in DNA transfection experiments using calcium phosphate precipitation. Included in these studies are the prototype isolate from a laryngeal papilloma (HPV 11P); HPV 11VC from a verrucous carcinoma of the penis; HPV 11Epi from the viral episomes of a primary squamous cell carcinoma; and two integrated genomes (HPV 11Int 1 and HPV 11Int 2) of the metastases. Only HPV 11VC cotransfected with the oncogene Ha-ras transformed neonatal rat kidney epithelial cells with an efficiency comparable to that of HPV 16 DNA. HPV 11VC DNA alone transformed NIH 3T3 cells. Analysis of the DNA sequence of HPV 11P and 11VC revealed 16 single nucleotide changes in the upstream regulatory region and open reading frames E1, E2, E4, and E5, five resulting in amino acid substitutions. This is the first demonstration of cellular transformation by a natural isolate HPV 11 DNA in vitro and illustrates that minimal changes in the DNA sequence of certain viruses confer oncogenicity to what are normally nontransforming viruses.


Modulation of colonic epithelial cell proliferation, histone acetylation, and luminal short chain fatty acids by variation of dietary fiber (wheat bran) in rats. The effect of increasing amounts of wheat bran (0, 5, 10, 20%) in AIN-76 semisynthetic diet on colonic luminal short chain fatty acids, epithelial cell histone acetylation, and cytokinetics, was studied for 2 weeks in groups of 10 male Sprague-Dawley rats. Luminal contents were removed from the colon at sacrifice, quick frozen, and analyzed for short chain fatty acids by gas-liquid chromatography. Histone acetylation was assessed in cells isolated from the same animals. Cell proliferation was measured after a short pulse in vivo with [3H]thymidine. Colonic luminal butyrate levels were lower in the 0 and 20% fiber groups, and higher in the 5 and 10% fiber groups. In contrast, cell proliferation, as determined by labeling index, was higher in the 0 and 20% fiber groups, and lower in the 5 and 10% fiber groups. This resulted in a significant inverse correlation between luminal butyrate levels and colonic cell proliferation. In addition, there was a positive linear correlation between luminal butyric acid levels and colon epithelial cell histone acetylation. From these data it was concluded that colonic butyrate levels can be modulated by the addition of wheat bran to the diet and that butyrate can modulate DNA synthesis (calculated as labeling index) in the proliferative compartments of colonic crypts. The localization of dividing cells was unchanged and no induction of terminal differentiation was detectable (contrary to what has been observed for transformed cells in culture).


Effects of 17 beta-estradiol metabolites on cell cycle events in MCF-7 cells. Different cell growth effects were observed in MCF-7 cells after six daily exposures to either 17 beta-estradiol (E2), 2-hydroxyestradiol (2-OHE2), or 2-methoxyestradiol (2-MeOE2) at 10 nM levels. 2-OHE2 enhanced cell growth significantly (P < 0.05) more than did the parent compound, whereas 2-MeOE2 inhibited cell growth. To identify the estrogen-affected cellular processes involved in cell cycle progression, hydroxy urea-synchronized MCF-7 cells were studied. No effects on DNA synthesis in mid-S-phase or on mitotic indices were observed after E2 or 2-OHE2 treatment. 2-MeOE2, however, significantly (P < 0.05) inhibited DNA synthesis and mitosis. Synchronized cells were exposed for 1 h to E2, 2-OHE2, or 2-MeOE2 before cAMP levels were determined in early S-phase and mid-S-phase, as well as during mitosis. E2 and 2-OHE2 had no effect, but 2-MeOE2 caused a significant (P < 0.05) increase in cAMP concentration in early S-phase and a decrease during mitosis. Phosphorylation of S-phase proteins was also studied. [32P]Pi incorporation was significantly (P < 0.05) enhanced in many proteins in 2-MeOE2-exposed cells. Small proteins (M(r) < 25,000), as well as large proteins (M(r) > 220,000), were most prominently affected. In comparison, E2 and 2-OHE2 had little effect. We suggest that the enhanced 2-MeOE2-induced protein phosphorylation during S-phase may affect S-phase events, which subsequently causes inhibition of mitosis. Protein synthesis during G2/M transition was unexpectedly enhanced by 2-OHE2 and was not enhanced by E2. [35S]Methionine incorporation into proteins in the order of M(r) 32,000-46,000, 47,000-50,000, 58,000-67,000, and 83,000-89,000 was significantly (P < 0.05) increased. 2-MeOE2 had no effect. The results of this study indicate that 2-OHE2 may be the more potent mitogen, whereas 2-MeOE2 acts as a cytostatin.


Human placental cells transformed with temperature-sensitive simian virus 40 are immortalized and mimic the phenotype of invasive cytotrophoblasts at both permissive and nonpermissive temperatures. Establishment of the human placenta is essential for subsequent development of the embryo. Previous studies from our laboratories have demonstrated that chorionic villus cytotrophoblast stem cells undergo a stepwise differentiation process in vivo that results in their ability to invade the uterine wall. This process can be mimicked by isolated primary first-trimester cytotrophoblasts in vitro. Efforts to study the regulation of this differentiation pathway have been hampered by the inability of the isolated cytotrophoblast to replicate in culture. We therefore performed experiments to determine the suitability of the temperature-sensitive simian virus 40-transformed cell line SPA 255-26 (SPA-26), derived from early-gestation cytotrophoblasts, for studying the cytotrophoblast differentiation pathway that results in uterine invasion. Our results show that this cell line exhibits many properties of differentiated early-gestation cytotrophoblasts at both permissive and nonpermissive temperature. These cells were invasive in vitro and expressed the repertoire of hormones, adhesion molecules, and proteinases characteristic of an advanced stage of cytotrophoblast differentiation in vivo. Thus, these cells should be useful in studying the regulation of the adhesive and invasive behavior of human cytotrophoblasts.


Gastrin stimulates Ca2+ mobilization and clonal growth in small cell lung cancer cells. Gastrin has been postulated to be a physiological growth factor, but compelling in vitro evidence of this has been difficult to obtain. In the present study we investigated whether small cell lung carcinoma cell lines could provide a useful model system to study the effects of gastrin on signal transduction and cell proliferation in vitro. We found that the addition of gastrin to small cell lung cancer cells loaded with the fluorescent Ca2+ indicator fura 2-tetraacetoxymethylester causes a rapid and transient increase in the intracellular concentration of Ca2+ ([Ca2+]i) followed by homologous desensitization. The [Ca2+]i response was especially prominent in the small cell lung carcinoma cell line H510. In this cell line, gastrin I, gastrin II, cholecystokinin residues 26-33 (CCK-8), and unsulfated CCK-8 increased [Ca2+]i in a concentration-dependent fashion with half-maximum effects at 7, 2.5, 3, and 5 nM, respectively. The Ca(2+)-mobilizing effects of gastrin and CCK-8 were prevented by proglumide, benzotript, and the specific gastrin/CCKB receptor antagonist L365260. Gastrin stimulated the clonal growth of H510 cells in semisolid (agarose-containing) medium, increasing both the number and the size of the colonies. Gastrin and CCK agonists were equally effective in promoting clonal growth. The broad-spectrum neuropeptide antagonists [D-Arg1,D-Phe5,D-Trp7,9,Leu11] substance P and [Arg6,D-Trp7,9,MePhe8] substance P (6-11) markedly inhibited gastrin-stimulated Ca2+ mobilization and clonal growth. These results show that gastrin acts as a direct growth factor through gastrin/CCKB receptors and demonstrate, for the first time, that these peptides can stimulate the proliferation of cells outside the gastrointestinal tract.


Mutation of p53 gene in hepatocellular carcinoma in Taiwan. To elucidate the role of p53 mutation in hepatocarcinogenesis in Taiwan, a hepatitis B viral infection hyperendemic area, exons 5 to 8 of the p53 gene in the tumor tissue of 61 hepatocellular carcinomas were amplified and sequenced. A total of 20 cases (32.8%) were found to have mutations; 36.6% (15 of 41) for the hepatitis B surface antigen positive group and 25.0% (5 of 20) for the hepatitis B surface antigen negative group. The corresponding normal liver showed no mutation. The mutation is widely distributed throughout exons 5 to 8. Only 4 cases (6.6%), all positive for hepatitis B surface antigen, had a specific hot spot mutation at codon 249 with G to T transversion. Our results show that scattered point mutations in p53 are not uncommon in hepatocellular carcinoma samples from Taiwan and may be important in the development of this cancer. However, the aflatoxin related specific mutation seems much less related to the genesis of hepatocellular carcinoma in Taiwan.


Human small cell lung cancer expresses the octamer DNA-binding and nervous system-specific transcription factor N-Oct 3 (brain-2). Small cell lung cancer (SCLC) cells express several characteristics of neuronal cells, including synthesis of neuropeptides and expression of the respective receptors. Establishment and maintenance of the neuronal phenotype of SCLC may depend on expression of gene transcription factors inherent to the central nervous system. The present study shows the nervous system-specific transcription factor N-Oct 3 (brain-2) to be expressed in all 13 SCLC cell lines investigated. Furthermore, N-Oct 3 (brain-2) was also found in SCLC-derived skin metastasis. In contrast, in extracts and RNA of non-SCLC cell lines and non-SCLC tumor tissues, such as lung squamous, large cell, and adenocarcinoma, expression of N-Oct 3 (brain-2) was not detectable. These data support the concept that SCLC cells derive from the neuroectodermal cell lineage since expression of N-Oct 3 (brain-2) protein is highly abundant at the neural tube stage and in the adult restricted to the neuroectodermal cell lineage.


Inherited WT1 mutation in Denys-Drash syndrome. Patients with the Denys-Drash syndrome (Wilms' tumor, genital anomalies, and nephropathy) have been demonstrated to carry de novo constitutional mutations in WT1, the Wilms' tumor gene at chromosome 11p13. We report three new cases, two carrying a previously described WT1 exon 9 mutation and one with a novel WT1 exon 8 mutation. However, unlike patients in previous reports, one of our three patients inherited the affected allele from his phenotypically unaffected father. This observation indicates that the WT1 exon 9 mutation affecting 394Arg demonstrated in over one-half of the patients with the Denys-Drash syndrome may exhibit incomplete penetrance. Consequently, familial studies in patients affected by this syndrome are recommended.


Medullomyoblastoma: report of two cases. Two cases of medullomyoblastoma in children are described. The muscular component showed different features in the two cases and were associated with neuronal differentiation. Morphological, immunohistochemical, and electron microscopical findings are presented. The origin of the muscular component is discussed in relation to the findings in other cases of the literature. Both differentiation from primitive neuroepithelial cells and derivation from ectomesenchyme are considered.


Characterization of structural defects in the lipopolysaccharides of symbiotically impaired Rhizobium leguminosarum biovar viciae VF-39 mutants. The lipopolysaccharides (LPS) of a wild type strain of Rhizobium leguminosarum biovar viciae (strain VF-39) and two symbiotically defective Tn5 mutants (VF-39-32 and VF-39-86) have been studied. The LPS of the mutants reflected impaired synthesis of the O-antigen. In the LPS of one mutant, the core tetrasaccharide was lacking and in that of the other it was truncated to a disaccharide containing mannose and 3-deoxy-D-manno-oct-2-ulosonic acid (KdO). The latter mutant also synthesized an unusual carbohydrate component containing mannose, galactose, and an unidentified saccharide. The lipid A composition was similar to that found in other strains of R. leguminosarum biovar viciae. The O-antigen of the wild-type bacterium contained 2-O-methylfucose, fucose, 3,6-dideoxy-3-(methylamino)hexose, glucose, 2-amino-2,6-dideoxyhexose, and heptose. This study clearly defines a role for the bacterial LPS in the proper functioning of the Rhizobium legume symbiosis.


In vivo tumorigenicity and in vitro sensitivity to tumor-necrosis-factor alpha mediated killing of c-Ha-ras-transformed cells. Cellular subclones of high and low tumorigenicity obtained from a mouse c-Ha-ras-transformed clone, were examined for their sensitivity to tumor-necrosis-factor (TNF)-mediated cytotoxicity. Cells of the highly tumorigenic subclones showed a significantly enhanced resistance to the cytotoxic effect of TNF plus cyclohexamide (CHI) as compared to cells of the low-tumorigenic subclones. The enhanced resistance to TNF+CHI was not due to a lower expression of TNF receptors on the cells. The c-Ha-ras-transfected cells were transformed and maintained in culture only (C cells). In vivo passage of cells of the initially low-tumorigenic c-Ha-ras subclones through the mouse significantly enhanced the tumorigenic potential of these CTC cells (culture/tumor/culture). In correlation with their enhanced tumorigenicity, the CTC cells were highly resistant to TNF-mediated cytotoxicity as compared to C cells of the same subclone. Furthermore, the involvement of TNF in determining the tumorigenic phenotype of the c-Ha-ras-transformed cells was demonstrated in a more direct manner. Cells of a c-Ha-ras-transformed low-tumorigenic, highly TNF-sensitive subclone were selected by repeated cycles of in vitro exposure to TNF alpha. As a result, a stable, highly TNF-resistant population of cells emerged. These TNF-resistant cells caused more tumors in mice as compared to their original TNF-sensitive cells. These results show that the resistance to the cytotoxic effect of TNF plus cyclohexamide may be involved, at least partially, in the tumorigenic potential of c-Ha-ras-transformed cells and suggest a possible role for TNF in the enhancement of the tumorigenic potential of these cells in mice.


Cytotoxic properties of a ricin A chain immunotoxin recognising the cluster-5A antigen associated with human small-cell lung cancer. The cytotoxic properties of a ricin A chain immunotoxin made with the mouse monoclonal antibody SWA20, recognising a family of sialoglycoprotein antigens selectively expressed by human small-cell lung cancer (SCLC), were examined using a panel of tumour cell lines in tissue culture. SWA20-ricin-A-chain was selectively toxic to the SW2, NCI-H69 and GLC-8 SCLC cell lines, inhibiting the incorporation of [3H]leucine by 50% at a concentration of 0.2-2 nM, but had no selective activity against the NCI-H23 and NCI-H125 lung adenocarcinoma or the control CEM T-lymphoblastoid cell lines. The SWA20 immunotoxin intoxicated the SW2 cell line rapidly, inhibiting [3H]leucine incorporation by 50% within 2 h compared with 0.5 h for ricin. Analysis of the effects of SWA20-ricin-A-chain on the growth of SW2 cells using a limiting-dilution clonogenic assay revealed that the immunotoxin could eliminate 95% of clonogenic malignant cells. Although SWA20-ricin-A-chain was found to be rapidly active against the majority of tumour cells, its action was limited by the presence of insensitive cells expressing low levels of the target antigen.


[Magnetic resonance tomography compared to computed tomography in the intracardiac spread of hepatocarcinoma]. A cirrhotic patient with inferior cava and right atrium-ventricular invasion by hepatic tumor was studied with transthoracic echocardiography (TTE), computerized tomography (CT) before and after contrast agent bolus iv, ECG-gated magnetic resonance imaging (MRI). Obesity obstacled abdominal echotomographic study; esophageal varices were relative contraindication to transesophageal echocardiography (TEE). The resolutive diagnosis was possible thanks to MRI which documented the spatial continuity among hepatic tumor, intracaval neoplastic thrombus and intracardiac mass. TTE can be considered the first step in case of suspected cardiac masses, but it is sometimes limited by the thorax conformation and not always discriminant. TEE is semi-invasive with important contraindications. CT is limited by the only axial or para-axial scans with low quality reconstructions, worsened in these cases by respiratory and cardiac movements. MRI can be considered the second step in the imaging of cardiac masses, immediately and directly after the echocardiographic techniques.


Further evidence for the presence of gamma-aminobutyric acidA (GABAA) receptors on the cytoplasmic side of Deiters' membrane. 1. The permeation of labeled Cl- across single nerve membranes microdissected from rabbit Deiters' neurons was studied in a microchamber system. The in----out permeation of the ions was evaluated under control conditions and in the presence of either 10(-6) M GABA or 10(-6) M GABA plus 10(-5) M bicuculline methiodide (BMI) on the membrane cytoplasmic side. 2. In 32 experiments, involving one animal each, at least two membranes served as controls and at least two others were studied with the addition of GABA. Within each experiment all the membranes were obtained from the same animal. 3. In an additional 10 experiments, involving one animal each, at least two membranes served as controls and at least two others were studied in the presence of GABA plus bicuculline methiodide on the membrane cytoplasmic side. 4. The data show that 10(-6) M GABA on the Deiters' membrane cytoplasmic side stimulates Cl- permeation in----out by 42% (P = 0.0000001). When 10(-5) M BMI was present together with GABA, no stimulation of Cl- in----out permeation occurred.


[Study of primary CMV infection in pregnant women]. Clinical data and samples of blood for detecting CMV antibodies were obtained from 716 pregnant women of whom, 6.84% and 95.61% had CMV IgM and CMV IgG antibody, respectively. Statistic analysis showed that high positivity rates of CMV IgM antibody were correlated with lower socioeconomic status, first pregnancy at less than or equal to 22 or greater than or equal to 29 years of age, and history of abortion, especially natural abortion. In the pregnant women primary CMV infection rates were not uniform in those of different occupations. Positivity rates of CMV IgM antibody were higher in medical workers and peasants (P less than 0.05).


[Epidemiological investigation on pathogens of acute infectious diarrhea in Ning Xia]. An epidemiological investigation on pathogens of diarrhoeal diseases in Ning Xia was reported. Eight genus of agents were found in all stool specimens of persons with detectable rate of 41.16%. Moreover, the most prevalent pathogens were shigella (19.59%), followed by rotaviruses (10.07%), salmonella (4.76%), and entero-pathogenic Escherichia coli (4.20%). Four of them accounted for 93.85% of detectable agents. In addition, in shigella B group made up 80.44%, and 2a was the predominant agent. Similarly S. typhimurium accounted for 85.71% in salmonella. The detectable rates in different age groups ranged from 27.21% to 59.89%. It was was lower in the groups under one year and over fifty and highest (59.89%) in the groups aged 20-49. Regarding seasonal variation, the detectable rate fluctuated from 31.25-50.13%, and the highest prevalence was obtained in autumn, whereas the lowest in the winter. Besides, the most commonly found agent in any seasons was shigella. In spring and autumn rotavirus was more frequently found. This study revealed that there were no significant differences between male and female, Hui and Han people, or urban and rural areas in detectable rates of agents.


Therapeutic ethanol injection of hepatocellular carcinomas undetectable by angiography and Lipiodol computed tomography. Seven smaller than 2 cm in diameter hepatocellular carcinomas (HCC) undetectable by hepatic arteriography and computed tomography (CT) after intraarterial injection of iodized oil (Lipiodol CT) were diagnosed by ultrasonography-guided fine-needle biopsy in 6 patients. All lesions were treated by percutaneous ethanol injection (PEI) in 1-3 weekly intervals. No recurrences have been demonstrated after 7-15 months. The treatment of HCCs undetectable by angiography and Lipiodol CT presents a problem as transcatheter arterial embolization is considered ineffective due to poor vascularity. PEI appears to be an excellent treatment for these small HCCs.


Subgroup and serotype epidemiology of human rotaviruses recovered at Ga-Rankuwa, southern Africa. This study analysed human rotaviruses isolated in Ga-Rankuwa, South Africa, using monoclonal antibodies directed at the subgroup-specific and serotype-specific antigens of the virus. The subgroup could be determined for 73pc of the specimens. Subgroup II viruses occurred more commonly than subgroup I viruses (77pc vs 22pc). A serotype specificity could be assigned in 65pc of cases with three serotypes observed to be circulating in this population. Serotype one strains were identified most commonly (43pc) with serotype two (12pc) and serotype four (9pc) strains also present. No serotype three strains were detected. One strain was identified which reacted with both subgroup I and II monoclonal antibodies and with serotype one and two monoclonal antibodies. This study highlights the unpredictable nature of the emergence of new serotypes and importance of surveillance of human rotavirus infection in this sub-continental region.


Drosophila ultraspiracle modulates ecdysone receptor function via heterodimer formation. The vertebrate retinoid X receptor (RXR) has been implicated in the regulation of multiple hormonal signaling pathways through the formation of heteromeric receptor complexes that bind DNA with high affinity. We now demonstrate that ultraspiracle (usp), a Drosophila RXR homolog, can substitute for RXR in stimulating the DNA binding of receptors for retinoic acid, T3, vitamin D, and peroxisome proliferator activators. These observations led to the search and ultimate identification of the ecdysone receptor (EcR) as a Drosophila partner of usp. Together, usp and EcR bind DNA in a highly cooperative fashion. Cotransfection of both EcR and usp expression vectors is required to render cultured mammalian cells ecdysone responsive. These results implicate usp as an integral component of the functional EcR. By demonstrating that receptor heterodimer formation precedes the divergence of vertebrate and invertebrate lineages, these data underscore a central role for RXR and its homolog usp in the evolution and control of the nuclear receptor-based endocrine system.


All-trans and 9-cis retinoic acid induction of CRABPII transcription is mediated by RAR-RXR heterodimers bound to DR1 and DR2 repeated motifs. Two cooperating retinoic acid response elements (RAREs) in the cellular retinoic acid-binding protein II (CRABPII) gene mediate differential transcriptional transactivation by retinoic acid receptors (RARs) and retinoid X receptors (RXRs) in P19 embryonal carcinoma cells. RARE1 and RARE2 are direct repeats (DR) of two motifs separated by 2 bp (DR2) and 1 bp (DR1), respectively, and bind RAR-RXR heterodimers more efficiently than homodimers. Using all-trans and 9-cis RA, which differentially activate RARs and RXRs, and RAR and RXR dominant-negative mutants, RAR-RXR heterodimers bound to RARE1 and RARE2 are shown to be responsible for CRABPII promoter transactivation, arguing against a unique DR spacing specifying recognition by RARs. Within heterodimers, RAR and RXR independently and differentially transactivate, depending on the specific RARE. Consistent with these results, 9-cis RA increases CRABPII mRNA levels more efficiently than all-trans RA. In contrast, all-trans and 9-cis RA have identical effects on induction of RAR beta 2 transcripts.


Inhibition of B cell proliferation by antisense DNA to both alpha and beta forms of Fc epsilon R II. Epstein-Barr Virus (EBV) infection activates B lymphocyte proliferation through partially understood mechanisms, resulting in phenotypic changes, including the appearance of new antigens. One such antigen is Fc epsilon R II/CD-23 which may be relevant for B cell proliferation. We have used anti-sense oligonucleotides to study the importance of the two forms of this molecule for proliferation in the EBV-transformed, Fc epsilon R II +ve lymphoblastoid B cell line, RPMI 8866. Anti-sense oligodeoxynucleotides were generated to the two forms of Fc epsilon R II; Fc epsilon R IIa (alpha) and IIb (beta) which differ only in their intracytoplasmic domains. Addition of increasing concentrations of anti-sense oligonucleotides, ranging from 1 to 30 microM, significantly decreased cellular proliferation as measured by the incorporation of [3H]thymidine (inhibition range 8-88%). Optimum inhibition of cellular proliferation was apparent at 15 microM concentration of both anti-sense Fc epsilon R IIa and IIb (Fc epsilon R IIa, mean +/- SE = 75 +/- 7% inhibition, p less than 0.001; Fc epsilon R IIb, mean +/- SE = 71 +/- 7% inhibition, p less than 0.001). Anti-sense oligonucleotides complementary to the common part of Fc epsilon R II resulted in a similar inhibition of proliferation. Sense oligonucleotides did not induce significant inhibition. Preincubation of sense and anti-sense oligonucleotides resulted in an abrogation of proliferation inhibition. Moreover, none of these oligonucleotides had any effect on a Fc epsilon R II -ve cell line. Incubation with both anti-sense IIa and IIb resulted in additive, but not synergistic inhibition of proliferation. Addition of soluble Fc epsilon R II did not reverse inhibition of proliferation, suggesting that membrane-bound or intracellular rather than soluble Fc epsilon R II was important for the induced proliferation. Analysis of cell surface expression for Fc epsilon II indicated that while there was a pronounced effect on cell number following incubation with anti-sense oligonucleotides, surface expression of Fc epsilon R II was consistent as measured over different time points. PCR analysis revealed that while most cells expressed either the alpha or the beta form of Fc epsilon R II, EBV-transformed cell lines, particularly RPMI 8866, were found to express both alpha and beta forms simultaneously. This may constitute a mechanism whereby EBV infection confers an immortal state to the cell, resulting in its uncontrolled proliferation. Cell lines expressing only one receptor form, either alpha or beta, were unaffected after incubation with anti-sense oligonucleotides.(ABSTRACT TRUNCATED AT 400 WORDS)


Involvement of a protein kinase C and protein phosphatases in adhesion of CD4+ T cells to and detachment from extracellular matrix proteins. For immune surveillance and function to be effective, T lymphocytes constantly recirculate via lymph and blood between lymphoid organs and body tissues. To enable efficient cell movement and migration, cell adhesion to components of the basement membrane and the extracellular matrix (ECM) must be a rapid and transitory process. Whether phosphorylation and dephosphorylation of cellular proteins are involved in this phenomena was explored by monitoring the adhesion of T cells to immobilized ECM proteins. A short exposure of 51Cr-labeled human CD4+ T cells to phorbol esters in vitro induced a rapid beta 1-integrin-mediated adhesion to both fibronectin and laminin, as determined by inhibition with anti-integrin antibodies. Adhesion was reversible; detachment from the immobilized ECM ligands occurred between 20 and 120 min without further intervention. This T cell adhesion was regulated by the activation of protein kinase C because (a) staurosporine and H-7 inhibitors of protein kinase C suppressed T cell adhesion, and (b) PMA-induced down-regulation of intracellular levels of protein kinase C was associated with the abrogation of the T cell adhesiveness to fibronectin and laminin. Furthermore, inhibition of protein phosphatases activity by okadaic acid delayed the detachment of the T cells from fibronectin or laminin. Thus, we suggest that T cell-ECM interactions such as adhesion and detachment are regulated, respectively, by protein kinase C and protein phosphatases.


Tumor necrosis factor alpha stimulates mycobactericidal/mycobacteriostatic activity in human macrophages by a protein kinase C-independent pathway. Tumor necrosis factor (TNF) is a 17-kDa protein produced by endotoxin-stimulated macrophages. We have demonstrated that recombinant human TNF activates human macrophages to kill intracellular bacteria of the Mycobacterium avium complex (MAC) in a dose-related manner. TNF also primed macrophages to produce superoxide anion (O2-) following treatment with phorbol esther PMA (0.1 micrograms/ml). To investigate the intracellular pathway involved in the TNF-mediated activation of mycobacteriostatic/mycobactericidal activity in macrophages, we used two different protein kinase C (PKC) inhibitors: H7 (10(-5)-10(7) M) and staurosporine (10(-7)-10(-9) M). Mellitin (1 and 100 mM) was used as a calmodulin inhibitor. Human peripheral blood-derived macrophages cultured for 7 days were treated with H7, mellitin, or staurosporine for 1 hr prior to incubation with TNF (10(3) U/ml). Twenty-four hours after treatment with TNF the O2- release was measured spectrophotometrically following exposure to PMA. Macrophages were infected with MAC and the viable intracellular bacilli were quantitated following 4 days of treatment with TNF. All PKC inhibitors suppressed O2- production after incubation with PMA. However, treatment with either PKC or calmodulin inhibitors did not influence the intracellular killing of M. avium by TNF-stimulated macrophages. Exposure of the macrophages to cGMP inhibitor but not to cAMP inhibitor significantly impaired the response to the stimulation with TNF. In contrast, incubation of macrophages with protein kinase A (PKA) had no effect on TNF-mediated mycobacteriostatic/mycobactericidal activity. These results suggest that the TNF-mediated mycobactericidal activity in cultured macrophages probably occurs by a PKC-independent mechanism.


Oxygen free radical generation and regulation of proliferative activity of human mononuclear cells responding to different mitogens. We have compared various mitogenic stimuli for their ability to induce hydrogen peroxide (H2O2) and superoxide anion (O2-) production by PBMC and the effect of these reactive oxygen species and hydroxyl radical (OH.) has been assessed on proliferation. Our results show that pokeweed mitogen (PWM) stimulated PBMC to release H2O2 which interfered with proliferation since inclusion of catalase enhanced PBMC thymidine uptake. In contrast, phytohemagglutinin (PHA) and monoclonal antibody to CD3 (alpha CD3) did not induce PBMC to generate H2O2. O2- release by PBMC, which is readily induced by phorbol myristate acetate (PMA), did not occur when the cells were stimulated with PWM, PHA, or alpha CD3. In correlation, the O2- scavenger enzyme superoxide dismutase (SOD) had no effect on the proliferative response of the cells to the same mitogens, whereas it impaired the thymidine uptake of PMA-stimulated PBMC. A regulatory role for OH. was implied by studies using a battery of OH scavengers known to inhibit PMA-stimulated PBMC proliferation. OH. scavengers markedly inhibited the lymphoblastic transformation of alpha CD3-stimulated cells but had little or no effect on PHA- and PWM-stimulated PBMC. Thus, one manner by which PBMC proliferation is regulated is through oxygen free radical production which varies depending on the type of mitogenic stimulus.


Incorporation of free fatty acids can explain alterations in the molecular species composition of phosphatidylcholine and phosphatidylethanolamine in human erythrocytes as induced by Plasmodium falciparum. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) species composition of human erythrocytes changes upon intraerythrocytic development of Plasmodium falciparum. Though the activity of the phosphotransferases which catalyze the last step of the Kennedy pathway for the synthesis of PC and PE is dependent of the species on diacylglycerol, it appeared that this cannot, by itself, explain the alterations found in PC and PE molecular species composition. When the incorporation of radiolabeled palmitic and stearic acids in PC and PE was studied, it became clear that differences in the incorporation of fatty acids in those phospholipids might be responsible for the observed alterations in their molecular species composition.


Autocrine stimulation of mas oncogene leads to altered growth control. Mas oncogene has been shown to have focus-inducing ability in NIH 3T3 cells which are tumorigenic in vivo in nude mice. Its stable expression in a variety of cell lines conferred some angiotensin responsiveness. To understand why mas-transfected cells exhibit a transformed phenotype and if angiotensin responsiveness plays any role in this process, we studied the growth characteristics of mas-transfected 3T3 cells and demonstrated that they lose contact inhibition, exhibit foci formation, and increased DNA synthesis even in absence of serum. Our results suggest that the transformed phenotype is due to the production of a mas receptor ligand distinct from angiotensin.


Changes in surface relief of suspended cells are morphological signs of the initial stage of neoplastic transformation in fibroblastic monolayer cultures. The percentages of cells with different types of cell surface relief were determined in cell suspensions derived from monolayer cultures. Primary cultures of rat embryo fibroblasts (REF) and cell lines REF (LT) and REF-1, immortalized cells of which preserved normal phenotypic characteristics of the initial primary culture REF, as well as morphologically transformed tumorigenic lines REF (LT) ras and REF-2EJ were studied. In REF suspensions the cells with the blebbed type of surface relief were shown to be predominant as compared with those with microvillus relief whereas cell suspensions derived from both immortalized and fully transformed cultures display the reverse ratio of cells with those types of surface relief. Therefore, the pattern of cell surface relief in cell suspensions derived from fibroblastic monolayer cultures may serve as a morphological marker of the initial stage of neoplastic transformation-immortalization when typical morphological signs of cell transformation are not yet manifested in monolayer cultures.


The influence of bilirubin on fluidity and rotational correlation times of human erythrocyte membrane. The effects of bilirubin on the membrane motion parameters of human erythrocyte membrane were determined by the spin labelled ESR method. It causes a decrease in the order parameter and an increase in the corresponding fluidity of the lipid molecules. Bovine serum albumin was found to inhibit effectively the effects due to bilirubin. The disturbance to the organization of membrane molecules by bilirubin as well as the protective effects of serum albumin are discussed on the basis of the experimental results.


Differentiation of quail myoblasts transformed with a temperature sensitive mutant of Rous sarcoma virus. II. Relationship of myoblast fusion with calcium and temperature. The effects of calcium and temperature on fusion of quail embryonic myoblasts were examined using cells transformed with a temperature-sensitive mutant of Rous sarcoma virus (ts-RSV). The transformed quail myoblasts (QM-RSV) fused to form myotubes at 41 degrees C, the non-permissive temperature, but not at 35.5 degrees C, the permissive temperature. On incubation at 41 degrees C, a period of more than 10 hr was needed for the myoblasts to become fusion-competent, but calcium was not needed for development of fusion-competence. Once the cells had become competent, fusion proceeded even at 35.5 degrees C. These results suggest that the src gene product expressed at 35.5 degrees C may control the fusion of cells in the competent stage by inactivating a component(s) that is associated with fusion-competence. However, fusion of even myoblasts in the competent stage was blocked in calcium-deficient medium, suggesting that calcium is essential for the fusion, probably at a step immediately before membrane union. Unlike fusion, other biochemical processes of differentiation proceeded even in calcium-deficient medium, indicating a distinction of fusion from these other processes during myoblast differentiation.


Transformation of Gibberella fujikuroi: effect of the Aspergillus nidulans AMA1 sequence on frequency and integration. A stable and reproducible transformation selection system for Gibberella fujikuroi protoplasts based on the Aspergillus nidulans arg B gene, encoding ornithine transcarbamylase, has been developed. Inclusion into the vector of the A. nidulans DNA fragment (AMA1), which permits plasmid autonomous replication in A. nidulans, A. niger and A. oryzae, appeared to permit autonomous replication of G. fujikuroi although the transformation frequency was increased by only two-fold. Transformation was also achieved using the bacterial hygromycin B resistance gene under the control of G. pulicaris and A. nidulans promoters.


[Plasma renin activity, angiotensin II, angiotensin converting enzyme, thromboxane A2 and prostacyclin I2 levels in pigs with severe hypoxia and hypercapnea and acidosis shock]. To evaluate the role of certain plasma biosubstances on the development of pulmonary hypertension and shock during severe hypoxia, hypercapnia and acidosis, plasma renin activity (PRA), angiotensin II (ATII), angiotensin converting enzyme (ACE), TXB2 and 6-Keto-PGF1 alpha (the stable metabolites of TXA2 and PGI2) were assayed in blood from pulmonary artery and aorta in seven pigs. Pulmonary arterial pressure (PAP) was monitored via Swan-Ganz catheter. During hypoxic and hypercapnic ventilation, PaO2 dropped to 4.7 kPa, PaCO2 rose to 21.1 kPa, pH dropped to 6.82, PAP increased from 2.43 +/- 0.06 to 4.46 +/- 0.45 kPa when acidotic shock developed (all P less than 0.05). Meanwhile ATII levels rose (all P less than 0.05). PRA significantly increased during acidotic shock as compared with normal ventilation (P less than 0.02). ACE dropped significantly (P less than 0.05), TXB2 and 6-keto-PGF1 alpha showed no significant change before and after hypoxic and hypercapnic ventilation.


[The changes in serum angiotensin-converting enzyme and their relationships to pulmonary failure in experimental model of multiple organ failure]. The correlation of serum angiotensin-converting enzyme (SACE), PaO2 and pulmonary coefficient in rabbit model of multiple system organ failure (MOF). 16 rabbits were fed E coli (0.5-3.0 x 10(11)/kg B.W.) by gastrogavage, were induced hemorrhagic shock (5.33 kPa arterial pressure for an hour) and were rapidly reinfused with shed blood and dextran. According to the criteria of pulmonary failure, that is respiratory rates greater than 100/min, PaO2 less than 8.00 kPa, pulmonary coefficient greater than 6.0, 8 rabbits developed pulmonary failure. They showed a significantly low SACE values, decreased PaO2 values and increased pulmonary coefficients, while in other 8 control animals the values of SACE and PaO2 did not significantly change.


[Primary pulmonary chemodectoma. Report of 2 cases and review of the literature]. The authors report two cases of primary pulmonary chemodectoma. The patients were admitted to the PUMC Hospital because of nodular lesion in the lung. The diagnosis was documented by postoperative pathology. Primary pulmonary chemodectoma is rare. Ten cases has been reported in the English literature. The clinical characteristic features is pulmonary single lesion on chest X-ray film. No correct diagnosis was made pre-operatively. A typical histopathological finding is observed. NSE and S-100 proteins is positive with immuno-histological stain. Surgery operation is the only reliable treatment.


[Evaluation of cellular immunity in pulmonary sarcoidosis and primary lung cancer]. We tested the cellular immunity of the patients with pulmonary sarcoidosis (n = 16) and primary lung cancer (n = 14). The data showed that PHA-p induced peripheral blood lymphocyte (PBL) proliferation and interleukin 2 (IL-2) productivity were significantly reduced in both patients groups, and also the PBL proliferation induced by exogenous recombined IL-2 was reduced, but not significantly (P > 0.05) compared with normal central. Our results suggested that cellular immunodepression may exist in pulmonary sarcoidosis and primary lung cancer patients, the exogenous IL-2 can partly restore the reduced PBL proliferation. So the cytokine may play a role in the immunologic treatment of lung cancer and the research of pulmonary sarcoidosis.


Reversal by nickel(II) of inhibitory effects of some scavengers of active oxygen species upon hydroxylation of 2'-deoxyguanosine in vitro. Effects of ethanol (EtOH), mannitol (Man), L-histidine (His) and glutathione (GSH) on the oxidation of 2'-deoxyguanosine (dG) to its 8-hydroxy derivative (8-OH-dG) with H2O2 plus L-ascorbic acid (Ascb) in the absence and presence of Ni(II) were investigated in order to unveil the nature of active oxygen species involved in that oxidation. In the absence of Ni(II), production of 8-OH-dG was inhibited by His much greater than GSH greater than or equal to GSSG (oxidized glutathione) much greater than EtOH, but not by Man. The latter tended to enhance the production of 8-OH-dG. In the presence of Ni(II), the inhibition by His, GSH and GSSG, but not EtOH, was prevented. The results indicate involvement of a 'crypto-hydroxyl' radical as the dG oxidizing species in both the absence and presence of Ni(II). Also, the results provide evidence that Ni(II) complexes with His, GSH and GSSG may lack antioxidant capacity. Moreover, the Ni(II) complex with His was found capable of enhancing 8-OH-dG production by the Ascb+H2O2 system to a greater extent than Ni(II) alone. Likewise, although to a lesser extent, the formation of 8-OH-dG was enhanced by the combination of Ni(II) and Man which do not form complexes at pH 7.4. Since His is a major Ni(II) carrier in animal tissues, the dG oxidation enhancing capacity of the Ni(II) complex with His may contribute to the toxic and carcinogenic effects of Ni(II).


Pathophysiological consequences of enhanced intracellular superoxide formation in isolated perfused rat liver. The potential toxicity of enhanced intracellular reactive oxygen formation was investigated in isolated perfused livers of male Fischer rats. The presence of the redox-cycling agent diquat in the perfusate (200 microM) increased the basal efflux of glutathione disulfide (GSSG) into bile (2.65 +/- 0.26 nmol GSH-equivalents/min per g liver wt.) and perfusate (0.55 +/- 0.15 nmol/min per g) approximately 10-fold. Since no evidence was found for degradation of GSSG in the biliary tract of these animals, it could be estimated that diquat induced a constant O2- generation of approximately 1000 nmol/min per g liver wt for 1 h. Thus, reactive oxygen formation under these conditions was 1-2 orders of magnitude higher than under various pathophysiological conditions. Only minor liver injury (release of lactate dehydrogenase activity) was observed. To increase the susceptibility of the liver to the oxidant stress, animals were pretreated in vivo with 200 mg/kg body wt. phorone, which caused a 90% depletion of the hepatic glutathione content, 100 mg/kg ferrous sulfate, a combination of phorone and ferrous sulfate, or 40 mg/kg BCNU, which caused a 60% inhibition of hepatic GSSG reductase. Only the combined treatment of phorone + ferrous sulfate or BCNU caused a significant increase of the diquat-induced liver injury. Our results demonstrated an extremely high resistance of the liver against intracellular reactive oxygen formation (even with impaired detoxification systems) and can serve as reference for the evaluation of potential contributions of reactive oxygen to liver injury in various disease states.


Perturbation effect of the diheptanoyl phosphatidylcholine on rat brain total lipid liposomes. An electron paramagnetic resonance spectroscopy study. Diheptanoyl phosphatidylcholine (DHPC) was reported to reduce inward sodium current in squid giant axons (Hendry et al., Biophys. J., 47, (1985) 841) and to decrease the frequency of the nicotinic acetylcholine-activated ion channel (Braun and Haydon, Pfügers Arch., 62, (1991) 418). To understand the DHPC effects, an influence of DHPC to increase dynamics/disorder (perturbation effect) in liposomes prepared from rat brain total lipids was studied at the 5th, 12th and 16th carbon membrane depths using the method of EPR spectroscopy of the spin labelled stearic acids and 1-palmitoyl-2-stearoyl phosphatidylcholines. The perturbation efficiency of DHPC in the liposomes was quantitated with the initial slope value of the order parameter S or inner splitting Amin versus DHPC concentration. DHPC at the DHPC/total lipid molar ratio of 1:10, 1:5, 1:3 and 1:2 increased dynamics/disorder of the liposomes. When the perturbation effect, compared at temperature scale, was normalized to 1 at the 5th carbon depth, the relative perturbation effect of DHPC was 1, 4.2, and 6.9 at the 5th, 12th and the 16th carbon depth, respectively, as detected by spin labelled stearic acids. Using the spin labelled lipids the perturbation effect was 1, 1.9 and 2.3, respectively. The differences of the perturbation effect of DHPC at different membrane depths correspond to the published perturbation effect of the local anesthetics lidocaine, tetracaine, dibucaine, heptacaine, IR-9 and carbisocaine on total lipid liposomes. The comparable perturbation properties of DHPC and of the local anesthetics support the hypothesis that the membrane perturbation caused by DHPC may play an important role in its effect on membrane function.


Copper and cobalt complexes of carnosine and anserine: production of active oxygen species and its enhancement by 2-mercaptoimidazoles. Phosphate buffer solutions of two dipeptides prevalent in striated muscle, L-carnosine (beta-alanyl-L-histidine) and L-anserine (beta-alanyl-L-1-methylhistidine), produce active oxygen species as measured by bleaching of N,N-dimethyl-4-nitrosoaniline (RNO). Activity is enhanced 5-14-fold in the presence of 2-mercaptoimidazoles such as ergothioneine, carbimazole (3-methyl-2-mercaptoimidazole-1-carboxylate), methimazole (2-mercapto-1-methylimidazole) and 2-mercaptoimidazole but only slightly by thiourea and dimethylthiourea. Activity is proportional to carnosine concentration and to mercaptoimidazole concentration at a fixed concentration of the second component. A variety of imidazoles closely related to carnosine and anserine are inactive, even after addition of transition metal ions. Activity is moderately increased above the pKa of the carnosine imidazole ring (pH 7.2, 7.5 and 8.0) versus below the pKa (pH 6.5 and 6.8). Activity is slightly increased by addition of copper or cobalt ions but not by addition of ferrous or ferric ions. Activity is decreased by Chelex 100 pretreatment of phosphate buffer and stimulated when copper or cobalt ions are added to the chelated buffer but there is no significant stimulation by ferric ions. Catalase eliminates most activity but superoxide dismutase has little effect. We propose that metal-carnosine and metal-anserine complexes produce superoxide and also serve as superoxide dismutases with resultant accumulation of hydrogen peroxide. An unidentified radical produced from hydrogen peroxide subsequently bleaches RNO. From the biological distributions of carnosine, anserine and ergothioneine, we infer that deleterious effects are probably minimal under normal physiological circumstances due to tissue and cellular compartmentalization and to sequestration of these compounds and transition metal ions.


Separation and some characteristics of two factors from rat liver particulate fraction which stimulate and inhibit the low-Km adenosine 3',5' cyclic monophosphate (cAMP) phosphodiesterase of rat fat cells. Two factors were separated from rat liver particulate fraction treated with insulin, one of them having a stimulating effect on low-Km adenosine 3',5' cyclic monophosphate (cAMP) phosphodiesterase activity of crude microsomal fraction (P-2 fraction) and the other having an inhibiting effect on the activity of low-Km cAMP phosphodiesterase solubilized with 0.3% Brij 58 from P-2 fraction. Trypsin and heat treatments had essentially no effect on these two factors. The stimulating factor did not significantly change the apparent Km value of enzyme in P-2 fraction but increased the maximal velocity of the reaction. The inhibiting factor raised the Km value of solubilized enzyme without affecting the maximal velocity of the reaction. The stimulating factor level in diabetic rat was larger than that in normal rat while the inhibiting factor level in diabetic rat was smaller than that in normal rat. Possible participation of both factors in insulin action is discussed.


Isolation of a metastasizing cancer cell line from an aflatoxin B1-induced rat liver tumor. An attempt was made to isolate cancer cell lines from liver tumors that had been induced by aflatoxin B1 (AFB1) in rats. A clonal cell line named AFB-1 was isolated from a liver tumor that was histologically diagnosed as hepatocellular carcinoma. When AFB-1 cells were inoculated into the subcutaneous tissue at the dorsal region of syngenic animals, they metastasized from the site of inoculation into the abdominal cavity to form many tumor nodules throughout the serous membrane and metastatic foci in the kidney and pancreas. They also metastasized into the thoracic cavity to form metastatic foci in the lung. This is the first instance where a metastasizing AFB1-induced cancer cell line has been isolated.


Interactions between local anesthetic dibucaine and pig erythrocyte membranes as studied by proton and phosphorus-31 nuclear magnetic resonance spectroscopy. The interactions between amine local anesthetic dibucaine and pig erythrocyte membranes have been studied by proton and phosphorus-31 nuclear magnetic resonance (1H- and 31P-NMR) spectroscopy. It was found that dibucaine, bound to the membranes, increases the mobility of the hydrophobic acyl chains of the phospholipids, but that it decreases the mobility and/or changes the structure of the polar headgroups. The interactions with peripheral membrane proteins, i.e., spectrin and actin, were found to be weak. These observations indicate that the dibucaine locates across the polar and hydrophobic areas of the lipid phase of the membranes by both electrostatic and hydrophobic interactions. It is assumed that the changes in the mobility and/or the conformation of the phospholipids residing around the Na channel protein are essential in causing anesthesia.


Isolation and structure elucidation of gymnemic acids, antisweet principles of Gymnema sylvestre. The structure of gymnemagenin (3 beta,16 beta,21 beta,22 alpha,23,28-hexahydroxy-olean-12-ene), the sapogenin of the antisweet principles of Gymnema sylvestre, was established by X-ray analysis of the 3 beta,23;21 beta,22 alpha-di-O-isopropylidene derivative. On the basis of this result, the structure of deacylgymnemic acid was elucidated as the 3-O-beta-glucuronide from the carbon-13 nuclear magnetic resonance spectra. Five antisweet principles, gymnemic acid-III, -IV, -V, -VIII, and -IX, were isolated in pure states from the hot water extract of leaves of Gymnema sylvestre. Of these, three (GA-III, -IV, and -V) were known, while two (GA-VIII and -IX) were new compounds. The structures of GA-VIII and -IX were elucidated as 3'-O-beta-D-arabino-2-hexulopyranosyl gymnemic acid-III and -IV, respectively.


Synthetic studies of vitamin D analogues. XI. Synthesis and differentiation-inducing activity of 1 alpha,25-dihydroxy-22-oxavitamin D3 analogues. Six analogues of 1 alpha,25-dihydroxy-22-oxavitamin D3 (OCT) (2), 26,27-dimethyl OCT (5), 26,27-diethyl OCT (6), 24-norOCT (7), 24-homoOCT (8), 24-dihomoOCT (9), and 24-trihomoOCT (10) were synthesized from the 20(S)-alcohol (11) as the common starting material. In the activity inducing differentiation of human myeloid leukemia cells (HL-60) into macrophages, 26,27-dimethyl OCT (5) and 24-homoOCT (8) showed the highest activities. The binding properties of these analogues to the chick embryonic intestinal 1 alpha,25-dihydroxyvitamin D3 (1) receptor are also described.


Isolation of novel lignans, heteroclitins F and G, from the stems of Kadsura heteroclita, and anti-lipid peroxidative actions of heteroclitins A-G and related compounds in the in vitro rat liver homogenate system. From the stems of Kadsura heteroclita, two new lignans named heteroclitins F and G were isolated and their structures were determined by various spectroscopic means including an X-ray diffraction method. Dibenzocyclooctadiene type lignans and related compounds isolated from the stems of K. heteroclita, potently inhibited the lipid peroxidation in the rat liver homogenate stimulated by Fe(2+)-ascorbic acid, CCl4-reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine 5'-diphosphate-NADPH.


Preferential utilization of glucose over melibiose, and vice versa, in a pts mutant of Salmonella typhimurium. Preferential utilization of glucose and melibiose was investigated in wild type cells and in pts mutant (ptsI-leaky) cells of Salmonella typhimurium. A typical diauxic growth and preferential utilization of glucose over melibiose were observed in wild type cells when these two sugars were added as carbon source. Similar results were obtained with a pts mutant (SB1476) although utilization of glucose was slow. When cyclic adenosine 3',5'-monophosphate (cAMP) was added to the culture medium to release the catabolite repression, preferential utilization of glucose was still observed in wild type cells. With glucose-induced mutant cells, preferential utilization of glucose was observed in the presence of cAMP. Gradual utilization of melibiose took place when glucose concentration in the medium decreased. Surprisingly, preferential utilization of melibiose over glucose was observed with melibiose-induced and glucose-uninduced mutant cells in the presence of cAMP.


[Effects of 1,25-(OH)2D3 on the secretion of growth hormone by human pituitary growth hormone-secreting tumors in vitro]. This work studied the effects of 1,25-(OH)2D3 on the secretion of growth hormone (GH) in 15 cases of human pituitary GH-secreting tumor cell cultures. At physiological doses (40-80 pg/ml) of 1,25-(OH)2D3, a GH secretion response was found in 14 cases of pituitary tumor: GH secretion was suppressed significantly in 9 of 14 cases and was markedly stimulated in only 2 of 14 cases of pituitary tumors. In the other 3 cases, the GH response was variable at different days of culture. The degree of suppression of GH secretion induced by 1,25-(OH)2D3 in all cases was 63.1 +/- 3.3% (means +/- sx of the control, and the average increase of GH secretion was 164.0 +/- 6.2% of control. There was no correlation between the type of GH reaction and the dose rang of 1,25-(OH)2D3 used in the experiment. The stimulatory effect on GH secretion did not appear after 2 weeks of culture. The results demonstrate that 1,25-(OH)2D3 at physiological doses has a direct regulatory effect (mainly suppressive) on GH secretion in most pituitary GH-secreting tumors in cell culture.


A biochemical hallmark of apoptosis: internucleosomal degradation of the genome. Apoptosis, or programmed cell death, is an endogenous cellular process whereby an external signal activates a metabolic pathway that results in cell death. This form of cell death appears to be a common feature in many biological processes where cell deletion is a mechanism for altering tissue structure and function. Historically, apoptosis has been studied using histological techniques; however, more recent interest has focused on analyzing this process at the biochemical level. A biochemical hallmark of apoptosis is a characteristic form of DNA degradation in which the genome is cleaved at internucleosomal sites, generating a 'ladder' of DNA fragments when analyzed by agarose gel electrophoresis. A number of assay systems have been developed to study this nuclease activity. For example, nuclease activity has been analyzed by measuring the release of endogenous DNA from apoptotic cells, by flow cytometric analysis of apoptotic cells and by analyzing in situ apoptotic nuclease activity in polyacrylamide gels containing DNA. Use of these assay systems has enabled investigators to study the signal transduction pathways that mediate apoptosis and to characterize the endonuclease itself. Future biochemical studies in this field will focus on isolating the genes and gene products that mediate apoptosis.


Apoptosis induced by anticancer drugs.

Apoptosis induced by anticancer drugs. Most of the cytotoxic anticancer drugs in current use have been shown to induce apoptosis in susceptible cells. The fact that disparate agents, which interact with different targets, induce cell death with some common features (endonucleolytic cleavage of DNA, changes in chromatin condensation) suggests that cytotoxicity is determined by the ability of the cell to engage this so-called 'programmed' cell death. The mechanism of the coupling of a stimulus (drug-target interaction) to a response (cell death) is not known, but modulation of this coupling may affect the outcome of drug treatment. This review surveys the recent evidence which supports the idea that the drug-target interaction per se is not the sole determinant of cellular sensitivity of cytotoxic drugs. Studies of the signals which might engage apoptosis, the genes which modulate it and the biochemical process of drug-induced apoptosis itself are described, where possible, for glucocorticoids, topoisomerase inhibitors, alkylating agents, antimetabolites and antihormones. It is suggested that identification of the gene products which couple the stimulus to the response, and so determine intrinsic cellular sensitivity (and resistance), will be important targets for new types of drugs. These might then allow responses to occur in the major cancers of man, which are chemoresistant.


In vitro enhancement of fluoropyrimidine-induced cytotoxicity by leucovorin in colorectal and gastric carcinoma cell lines but not in non-small-cell lung carcinoma cell lines. Leucovorin (LV) increases the cytotoxic effect of fluorouracil (FUra) and 5-fluoro-2'-deoxyuridine (FdUrd) by enhancing the formation of the fluorodeoxyuridine monophosphate (FdUMP) thymidylate synthase (TS) 5,10-methylenetetrahydrofolate (mTHF) ternary complex. To study the difference in the efficacy of this combination against different tumors, we compared the effect of LV (20 microM) on the cytotoxicity of FUra, FdUrd, and 5-fluorouridine (FUrd) in vitro against cell lines of five colorectal carcinomas (CC), five gastric carcinomas (GC), and four non-small-cell lung carcinomas (NSCLC) using the colony-forming assay. At the concentration used in the experiments, LV alone failed to inhibit colony formation in any of the cell lines tested. The NSCLC cell lines were more resistant to FdUrd than were the CC and GC lines. LV modulated the cytotoxicity of FdUrd in all five CC lines and in three of the five GC lines but failed to do so in any of the NSCLC lines. In addition, following 20 h treatment with 1 microM [3H]-FdUrd, formation of the FdUMP/TS/mTHF ternary complex was enhanced by LV in the LV-sensitized CC and GC cell lines but not in the LV-refractory NSCLC lines. These in vitro data corresponded well to the results of clinical trials. Therefore, the colony-forming assay may be useful for the identification of the sensitivity of tumors according to phenotype.


Phase II study of Edatrexate in stage III and IV non-small-cell lung cancer. A total of 49 patients with advanced, previously untreated non-small-cell lung cancer (NSCLC) were treated with a new antifolate, Edatrexate (10-ethyl-10-deaza-aminopterin; 10-EdAM). Patients received 80 mg/m2 weekly for 12 weeks, and responders received a further 6 cycles at 2-week intervals. Dose reductions were carried out for haematological toxicity and mucositis. Response was assessed prior to each treatment according to WHO criteria. Among the 45 evaluable patients, 6 [13.3%; 95% confidence interval (CI), 6%-26%] achieved a partial response (PR) and 9 (20%; 95% CI, 11%-34%) showed a minor response (MR; 25%-50% reduction in the sum of 2 perpendicular tumour diameters). In those receiving four or more cycles of treatment, the PR and MR rates were 17.6% and 26.4%, respectively. The resultant toxicity mainly constituted skin rash, mucositis and myelosuppression. Edatrexate is active against NSCLC and produces toxicity profile similar to that of methotrexate.


Concurrent radiation and weekly cisplatin for non-small-cell lung cancer--a phase I/II study. A total of 20 patients with loco-regional non-small-cell lung carcinoma were entered into a study of irradiation (3.0 Gy x 15 doses to a total dose of 45 Gy given in 4 fractions per week on days 1, 2, 4 and 5 of each week) and cisplatin given at a dose of 40 mg/m2 on day 3 of each week for a total of three infusions. One patient who had stage 1 disease showed a complete response to therapy and is alive and clear of disease at 35 months. In 19 patients with stage 3 disease, the complete response rate was 16% and the partial response rate was 42%. The rate of 1-year survival was 42% and the rate of 2-year survival was 11%; the median survival of these patients was 11 months. Relapse occurred, mostly at metastatic sites, in 10 of the 11 patients who responded to therapy. Acute toxicity was modest and tolerable by our patients. No severe late toxicity was encountered, and none of the patients developed grade 3 dyspnoea (an inability to walk 100 yards because of breathlessness) while clear of recurrent disease. Changes in lung function observed at follow-up examinations were similar to those seen after irradiation alone. Weekly administration of cisplatin is therefore feasible in patients receiving a continuous course of irradiation. The high relapse rate observed in responding patients indicates the need for evaluation of the efficacy of combination chemotherapy in the adjuvant or neo-adjuvant setting.


DNA polymerase, RNA polymerase and exonuclease activities on a DNA sequence modified by benzo[a]pyrene diolepoxide. Adducts produced by modification of DNA with benzo[a]pyrene diolepoxide (BPDE) are known to inhibit both DNA and RNA synthesis. This phenomenon has been used as a method for determining the distribution of carcinogen binding within defined DNA sequences. A critical comparison of different enzyme activities on adducted DNA is needed, since different enzymes may process adducted DNA differently. Thus, we compared blocks in DNA polymerase activity with that of an RNA polymerase and with an exonuclease at single base resolution. BPDE adducts blocked the progression of cloned T7 DNA polymerase (Sequenase) in a dose-dependent manner. Although the majority of these blocks were at one base prior to adducted guanines, we also observed some blocks opposite specific guanines, suggesting that in some sequences the polymerase inserted a base opposite the modified guanine. Digestion with T4 DNA polymerase (3'----5') exonuclease activity was also blocked in BPDE-adducted DNA; however, fragments produced by blocks in T4 exonuclease migrated two or more bases longer than the corresponding guanine. Mapping of adduct distributions using both Sequenase and T4 exonuclease gave similar results, demonstrating that a long tract of guanines was preferentially modified, and within a polyguanine sequence, the 5' guanines were more heavily modified than the 3' guanines. Transcription of adducted DNA by SP6 RNA polymerase was also inhibited in a dose-dependent manner. However, adducted bases which posed strong blocks to the DNA polymerase were not always strong blocks to the RNA polymerase. Thus, in terms of adduct distribution, Sequenase and T4 exonuclease provided more consistent results than the RNA polymerase, since blockage of the RNA polymerase correlated poorly with guanines.


The electronic and thermodynamic aspects of Ah receptor binding. A new structure-activity model: I. The polychlorinated dibenzo-p-dioxins. A new quantitative structure-activity model for the aromatic hydrocarbon (Ah) receptor, which completely eliminates multiple regression analysis in its formulation, is reported. Taking the polychlorinated dibenzo-p-dioxins (PCDDs) as model xenobiotics, the binding affinity of a PCDD relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was found to be analytically related to the electron affinities, entropies and lipophilicities of PCDD and TCDD. The reported mathematical model is capable of qualitatively explaining and quantitatively estimating the in vitro binding affinities of PCDDs and related xenobiotics to the Ah receptor. Accordingly, a halogenated aromatic compound is expected to have a high affinity for the cytosolic protein compared to TCDD if it is less lipophilic, has a higher electron affinity and lower entropy than TCDD. In addition, the LD50s of PCDDs in selected mammalian species are shown to have similar sigmoidal dependence on their lipophilicities, electron affinities and entropies, in agreement with the hypothesis that the toxicities of PCDDs and related xenobiotics are mediated through binding to the Ah receptor and that the trend in the LD50s and other toxic responses of PCDDs in animals are similar.


In vitro activation of the dioxin receptor to a DNA-binding form by food-borne heterocyclic amines. The carcinogenic heterocyclic amines, which are formed upon cooking of protein-rich food, are activated in the body mainly by cytochrome P450 IA1 and IA2. Several of these co-called food mutagens have, by enzymatic and immunoblotting techniques, been shown to be weak inducers of cytochrome P450 IA in the rat. To elucidate whether this induction occurs via the dioxin receptor, the capacity of the heterocyclic amines to activate in vitro the dioxin receptor to a DNA-binding form was determined. The activation of the receptor in Hepa cell cytosol was analyzed with a gel-retardation assay using a [32P]3'-end-labeled synthetic oligonucleotide, corresponding to nucleotides -1026 to -999 of the rat cytochrome P450 IA1 gene (XRE1), as probe. Five out of 14 heterocyclic amines had the ability to induce specific DNA-binding activity in the Hepa cell cytosol in a dose-dependent manner. The concentrations eliciting 50% of the maximal effect (EC50) were found to be between 30 and 135 microM. Thus, in comparison to high-affinity ligands such as benzo[a]pyrene (B[a]P; EC50 11.2 nM), and 2,3,7,8-tetrachloro-1,6-dibenzo-p-dioxin (TCDD; EC50 1.9 nM), the activating capacity of the heterocyclic amines is low. Binding to the dioxin receptor has been shown to be dependent on the three-dimensional size of a molecule in relation to a 6.8 x 13.7 A rectangle. The relatively low EC50 values found for the heterocyclic amines might be explained by the smaller size of these molecules when compared to that of B[a]P and TCDD.


Production of 8-hydroxydeoxyguanosine in isolated DNA by chromium(VI) and chromium(V). Chromium(VI) and Cr(V) compounds increased the concentration of 8-hydroxydeoxyguanosine (oh8dG) in isolated DNA, whereas no such increase was seen with Cr(III). Furthermore, incubating DNA with H2O2 and Cr(VI) or Cr(V) potentiated the formation of oh8dG above levels observed with either chromium compound alone. In the presence of catalase, the increase in DNA oxidation observed with Cr(VI) was inhibited, the base oxidation observed being equivalent to background levels, and this indicated involvement of H2O2 in the mechanism. Glutathione did not enhance chromium-induced formation of this oxidized base. These results help to explain a mechanism of chromium-induced DNA oxidation involving H2O2 via a Fenton-type reaction.


Polymicrobial sepsis disrupts normal neutrophil extracellular matrix protein interactions. The purpose of this study was to examine how intra-abdominal sepsis and extracellular matrix proteins (fibronectin, laminin) affect adherent polymorphonuclear leukocyte (PMN) function. Two groups of swine were studied: Group I (n = 5) underwent sham laparotomy; Group II (n = 8) underwent cecal ligation and incision. PMN adherent to either fibronectin (F) or laminin (L) had increased candicidal activity over buffer (B) by Group I but not by post-operative day 8 Group II PMN. (Percent specific release 51Cr-Group I--35.00, 68.25, 64.75% for B, F, and L; P less than 0.001 comparing B vs. F or L; Group II--14.25, 12.50, 12.75% for B, F, and L; P = NS comparing B vs. F or L.) To determine the mechanism for this finding, PMN priming was then assessed by evaluating both PMN adherence to extracellular matrix proteins and the cell surface expression of CR1/CR3 by using sheep RBC opsonized with C3b or C3bi. PMN activation was assayed by using MTT-Formazan, myeloperoxidase, and hypochlorous acid (HOCl) production. Fibronectin and laminin increased PMN adherence and CR1/CR3 expression over buffer by Group I and Group II animals. Fibronectin and laminin increased MTT-Formazan, myeloperoxidase, and HOCl production over buffer by Group I PMN but not POD 8 Group II PMN. These results suggest that untreated intra-abdominal sepsis partially abrogates the effect of extracellular matrix proteins on PMN function; in particular, the activation but not priming of adherent PMN by extracellular matrix proteins is reduced in this clinical situation.


Effect of caffeine on expression of cardiac myosin heavy chain gene in adult hypothyroid and fetal rats. Changes in cardiac myosin heavy chain (MHC) gene expression and isozyme transitions have been shown to be caused by developmental changes, hemodynamic overload, or the activity of various hormones. In this study, to examine whether caffeine, which has teratogenic effects on the fetal cardiovascular system, causes the distribution of cardiac MHC phenotype and, if so, to evaluate the mechanisms of the distribution of cardiac MHC phenotype by caffeine, we examined the effects of caffeine, theophylline, and cAMP on the cardiac MHC isoform transitions at the gene and protein levels using hypothyroid adult rats. Furthermore, we examined the expression of alpha- and beta-MHC gene in cardiac muscles of fetuses whose dams had received caffeine. The results showed that caffeine, theophylline, and cAMP caused accumulations of alpha-MHC mRNA and MHC isozyme V1. Furthermore, in the fetal hearts, it was recognized that caffeine induced an accumulation of alpha-MHC gene expression, as was also seen in the dams. However, this effect of caffeine on the heart was stronger in the fetus than in the dam. Intracellular cAMP concentration was increased by the administration of caffeine, theophylline, or cAMP, and the levels showed a positive correlation with those of alpha-MHC mRNA. These results suggest that the induction of alpha-MHC mRNA expression by the administration of caffeine may be induced by an increase in intracellular cAMP concentration.


Platelet-derived growth factor suppresses and fibroblast growth factor enhances cytokine-induced production of nitric oxide by cultured smooth muscle cells. Effects on cell proliferation. Stimulation of thymidine incorporation by basic fibroblast growth factor or epidermal growth factor treatment of cultured quiescent smooth muscle cells (rat and human) was attenuated by the concomitant treatment with interleukin-1 beta in the presence of indomethacin. Platelet-derived growth factor-AB and -BB-induced thymidine incorporation was not inhibited by the presence of the cytokine under similar experimental conditions. Elevation of nitrite levels in the conditioned medium of cultures exposed to interleukin-1 beta correlated with the inhibition of thymidine incorporation. Platelet-derived growth factor-AB and -BB inhibited the production of nitric oxide (measured as nitrite levels in conditioned medium) by cells treated simultaneously with interleukin-1 beta and growth factor. However, platelet-derived growth factor-AA neither affected nitrite production nor thymidine incorporation by smooth muscle cells. Levels of cytokine-stimulated nitrite production by smooth muscle cells were increased synergistically by the presence of fibroblast growth factors or epidermal growth factor. The inhibition of thymidine incorporation and concomitant elevation of nitrite production was abolished in the presence of nitro-L-arginine. Cultures maintained in the presence of low levels of the cytokine for 9 days were growth-inhibited, and this was reversed when culture medium was supplemented with nitro-L-arginine. The treatment of smooth muscle cells, which were grown in coculture inserts with the cytokine to induce nitric oxide production, before their combination with other quiescent layers of cells resulted in the inhibition of thymidine incorporation by this second layer of cells regardless of the growth factor used for stimulation. Nitric oxide may act as an endogenous inhibitor of smooth muscle cell proliferation in the vessel wall, and impairment of its production may be one action of potent vascular mitogens such as platelet-derived growth factor.


Inward sodium current at resting potentials in single cardiac myocytes induced by the ischemic metabolite lysophosphatidylcholine. To investigate possible ionic current mechanisms underlying ischemic arrhythmias, we studied single Na+ channel currents in rat and rabbit cardiac myocytes treated with the ischemic metabolite lysophosphatidylcholine (LPC) using the cell-attached and excised inside-out patch-clamp technique at 22 degrees C. LPC has been reported previously to reduce open probability and to induce sustained open channel activity at depolarized potentials. We now report two new observations for Na+ currents in LPC-treated patches: 1) The activation-voltage relation of the peak of the ensemble currents is shifted in the negative (hyperpolarizing) direction by approximately 20 mV compared with control currents. This effect was observed in all patches for depolarizations from a holding potential of -150 mV to different test potentials. 2) In some LPC-treated patches, Na+ channels exhibited sustained bursting activity at potentials as negative as -150 mV, giving a nondecaying inward current. This bursting activity was accompanied by double and triple simultaneous openings and closings, suggesting tight cooperativity in channel gating. These LPC-modified channels were identified as Na+ channels, because their unitary conductance was the same as Na+ channels in control solutions, because the single channel current-voltage relation was extrapolated to reverse at the Na+ Nernst potential, and because the current was blocked by the local anesthetic QX-222. This novel depolarizing current may play a role in the electrophysiological abnormalities in ischemia, including abnormal automaticity and reentrant arrhythmias, and could be a target for antiarrhythmic drugs.


Endothelin-1 enhances calcium entry through T-type calcium channels in cultured neonatal rat ventricular myocytes. Endothelin-1 (ET-1), a 21-amino acid vasoconstrictive peptide, increases intracellular Ca2+ level and has hypertrophic action on ventricular myocytes. To elucidate a possible role of Ca2+ entry through sarcolemmal Ca2+ channels on this ET-1 action, we examined effects of ET-1 on L-type (ICa,L) and T-type (ICa,T) Ca2+ currents in cultured neonatal rat ventricular myocytes using the patch-clamp technique. ET-1 at a concentration of 10 nM increased the maximum current density of ICa,T from -3.0 +/- 1.4 microA/cm2 in the control condition to -4.4 +/- 1.6 microA/cm2 (p < 0.01). Although the peak amplitude of ICa,L was decreased during ET-1 application (from -9.7 +/- 1.9 microA/cm2 in the control condition to -5.0 +/- 1.4 microA/cm2 [p < 0.01]), this magnitude of decrease in ICa,T (52 +/- 19%) was comparable to that of spontaneous "run-down" of ICa,L (47 +/- 26%). The enhancement of ICa,T by ET-1 was dose dependent; it was initiated as low as 0.32 nM, and the maximal response was attained at approximately 10 nM, with a half-maximal dose of 1.26 nM. The enhancement of ICa,T by ET-1 was antagonized by protein kinase C inhibitors staurosporine (0.2 microM) and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7, 20 microM) applied to the pipette solution. Extracellular application of tumor-promoting phorbol esters, phorbol 12,13-dibutyrate (PDBu) and 4 beta-phorbol 12-myristate 13-acetate, augmented ICa,T. PDBu (0.2 microM) increased the maximal current density of ICa,T from -4.2 +/- 0.5 microA/cm2 in the control condition to -5.5 +/- 1.0 microA/cm2 (p < 0.01). In the presence of H-7 (20 microM) in the pipette solution, PDBu failed to enhance ICa,T, and an inactive isomer of PDBu (4 alpha-phorbol 12,13-dibutyrate, 0.2 microM) did not augment ICa,T. Thus, ET-1 enhances Ca2+ entry through the sarcolemmal T-type Ca2+ channel, possibly through a pathway involving activation of protein kinase C. This ET-1 action may be involved in the rise of the intracellular Ca2+ level and may contribute to the induction of cardiac hypertrophy by ET-1.


Molecular biology of the natriuretic peptides and their receptors. After the description in the past 5 years of BNP and CNP, interest in the natriuretic peptide family has dramatically increased. Molecular characterization of the receptors for this hormone family has identified a heterogeneity in the receptor subtypes not previously alluded to by pharmacological or biochemical studies. Much has been published on the physiology of ANP, but the major roles for BNP and CNP remain to be elucidated. Some experiments indicate that ANP and BNP may act synergistically, especially during cardiac stress; however, the high level of structural diversity of BNP among species and the ability of porcine BNP, but not human BNP, to activate human NPR-B suggest that an as yet unidentified receptor may exist that specifically recognizes BNP. Localization studies have implied that CNP is the most prominent neuropeptide in the natriuretic peptide family, and the restriction of its receptor, NPR-B, to the nervous system suggests that CNP and NPR-B may act in the brain to coordinate the central aspects of body fluid homeostasis. Of the three known NPRs, two, NPR-A and NPR-B, are capable of synthesizing their own second messenger, cGMP. The domain within these receptors that has high homology to protein kinases has been demonstrated to be essential for regulating this activity. No kinase activity has been measured in these proteins, but it is possible that this region is important for ATP regulation of guanylyl cyclase activity. This possibility raises interesting parallels with receptor-mediated cAMP signaling within cells. Seven transmembrane receptors, once activated by ligand, associate with G proteins to affect the activity of adenylyl cyclase.(ABSTRACT TRUNCATED AT 250 WORDS)