Involvement of arginine residues in the allosteric activation and inhibition of Synechocystis PCC 6803 ADPglucose pyrophosphorylase. ADPglucose pyrophosphorylase (EC 2.7.7.27) from the cyanobacterium Synechocystis PCC 6803 was desensitized to the effects of allosteric ligands by treatment with the arginine reagent, phenylglyoxal. Enzyme modification by phenylglyoxal resulted in inactivation when the enzyme was assayed under 3P-glycerate-activated conditions. There was little loss of the catalytic activity assayed in the absence of activator. Pi, 3P-glycerate, and pyridoxal-P were able to protect the enzyme from inactivation, whereas substrates gave minimal protection. The protective effect exhibited by Pi and 3P-glycerate was dependent on effector concentration. MgCl2 enhanced the protection afforded by 3P-glycerate. The enzyme partially modified by phenylglyoxal was more resistant to 3P-glycerate activation and Pi inhibition than the unmodified form. Vmax at saturating 3P-glycerate concentrations and the apparent affinity of the enzyme toward Pi were decreased upon phenylglyoxal modification. Incorporation of labeled phenylglyoxal into the enzyme was proportional to the loss of activity. Pi and 3P-glycerate nearly completely prevented incorporation of the reagent to the protein. Results suggest that one arginine residue per mol of enzyme subunit is involved in the binding of allosteric effector in the cyanobacterial ADPglucose pyrophosphorylase.


Structural domains of phytochrome deduced from homologies in amino acid sequences. A method of semiempirical identification of structural domains is proposed. The procedure is based on the comparison of amino acid sequences in groups of homologous proteins. This approach was tested using 32 known protein sequences from different cytochrome b5, cytochrome c, lysozyme, hemoglobin, and myoglobin proteins. The method presented was able to identify all structural domains of these reference proteins. A consensus secondary structure provided information on structural content of these domains predicting correctly 21 of 23 (91%) of alpha-helices. We applied this method to six homologous phytochrome sequences from Avena, Arabadopsis, Cucurbita, Maize, Oryza, and Pisum. Some of the identified domains can be assigned to the known tertiary structure categories. For example, an alpha/beta domain is localized in the region known to stabilize the phytochrome chromophore in the red light absorbing form (Pr). One alpha-helical and one alpha/beta domains are localized in regions important for the chromophore stabilization in the far-red absorbing form (Pfr). From an analysis of noncovalent interaction patterns in another domain it is proposed that a phytochrome dimer contact involves two segments localized between residues 730 and 821 (using numbering of aligned sequences). Also, a possible antiparallel beta-sheet structure of this region has been suggested. According to this model, the long axis of the interacting structures is perpendicular to a twofold symmetry axis of the phytochrome dimer.


The functional, oxygen-linked chloride binding sites of hemoglobin are contiguous within a channel in the central cavity. Chloride ion is a major allosteric regulator for many hemoglobins and particularly for bovine hemoglobin. A site-directed reagent for amino groups, methyl acetyl phosphate, when used for global rather than selective modification of R (oxy) and T (deoxy) state bovine hemoglobin, can acetylate those functional amino groups involved in binding of chloride; the extensively acetylated hemoglobin tetramer retains nearly full cooperativity. The chloride-induced decrease in the oxygen affinity parallels the acetylation of bovine hemoglobin (i.e., their effects are mutually exclusive), suggesting that methyl acetyl phosphate is a good probe for the functional chloride binding sites in hemoglobins. Studies on the overall alkaline Bohr effect indicates that the part of the contribution dependent on chloride and reduced by 60% after acetylation is due to amino groups, Val-1(alpha) and Lys-81(beta); the remaining 40% is contributed by the imidazole side chain of His-146(beta), which is not acetylated by methyl acetyl phosphate, and is not dependent on chloride. The five amino groups--Val-1(alpha), Lys-99(alpha), Met-1(beta), Lys-81(beta), and Lys-103(beta)--of bovine hemoglobin that are acetylated in an oxygen-linked fashion are considered functional chloride binding sites. Molecular modeling indicates that these functional chloride binding sites are contiguous from one end of the central cavity of hemoglobin to the other; some of them are aligned within a chloride channel connecting each end of the dyad axis.(ABSTRACT TRUNCATED AT 250 WORDS)


Evidence for an arginine residue at the allosteric sites of spinach leaf ADPglucose pyrophosphorylase. The covalent modification of spinach leaf ADPglucose pyrophosphorylase leads to inactivation of both activator-stimulated and -unstimulated activity. Inactivation can be prevented if either the activator 3PGA or the inhibitor Pi are present during the modification. Pi proved to be more effective at protecting the enzyme from inactivation as it afforded 50% protection at 51 microM compared to 50% protection by 405 microM 3PGA. Partial modification of the enzyme using [14C]-phenylglyoxal leads to a decrease in both Vmax, A0.5 and a decrease in the ability of the 3PGA to stimulate the enzyme's activity. Modification increased the enzyme's susceptibility to inhibition by Pi and completely abolished the cooperative binding of Pi seen in the unmodified enzyme in the presence of 3PGA. Thus, phenylglyoxal appears to interfere, with the normal allosteric regulation of ADPglucose pyrophosphorylase from spinach leaf. Greater than 90% of the enzyme's activity is lost when 7.2 mol [14C]-phenylglyoxal are bound per mole of tetramer and this label is present in both the larger and small subunits. In addition, inactivation appears to involve two different arginine residues having different rates of modification.


Proton NMR assignments of systemin.

Proton NMR assignments of systemin. Complete proton NMR assignments have been made for a synthetic 18-amino acid peptide named systemin, which functions as a wound-induced polypeptide hormone in tomato plants, and three of its derivatives. The wild-type peptide and this synthetic homolog have equivalent activities in their functional roles as systemic inducing signals in tomato plants. Proton NMR studies were carried out to characterize the solution properties of systemin. A variety of homonuclear proton NMR experiments at both 500 and 600 MHz were utilized in making these assignments, which have resulted in additional structural information. Whereas these results provide no evidence for persistence of common secondary (helix, sheet) or tertiary structural elements in the systemin polypeptide, there is evidence for two distinct molecular conformations at the carboxy terminus.


Regulation of growth and gene expression in human papillomavirus-transformed keratinocytes by transforming growth factor-beta: implications for the control of papillomavirus infection. Cervical carcinogenesis is a multistep process that appears to be initiated by infection of squamous epithelial cells in the cervix with one of a limited number of human papillomavirus (HPV) types. However, the mechanisms involved in the evolution of benign, HPV-induced lesions to malignancy have not yet been fully elucidated. Transforming growth factor-beta (TGF-beta), a multifunctional growth factor produced by cells in the skin, inhibits the proliferation of foreskin and cervical keratinocytes in vitro. We examined the effects of TGF-beta on growth and virus early-gene expression in cell lines immortalized by two HPV types associated with cervical carcinogenesis as well as the expression of TGF-beta 1 mRNA transcripts in normal and HPV-positive cells in vivo and in vitro. We found that normal and HPV-positive cells expressed similar levels of TGF-beta 1 mRNAs and exhibited similar patterns of responsiveness to three isoforms of TGF-beta in both monolayer and modified organotypic cultures. Of particular interest is our finding that the expression of the E6 and E7 early viral transforming regions of both HPV16 and HPV18 was reversibly and rapidly inhibited by TGF-beta. In one HPV16-positive cell line examined in detail, inhibition of HPV expression required protein synthesis and occurred at the level of transcription. HPV-immortalized cells selected for resistance to in vitro differentiation signals remained sensitive to TGF-beta-mediated growth inhibition. These results, showing that both growth and virus gene expression in HPV-transformed cells were responsive to TGF-beta, suggest that endogenous growth factors produced by different cell types in squamous epithelium may play a role in the progression of cervical neoplasia.


Kinds of mutations induced by aflatoxin B1 in a shuttle vector replicating in human cells transiently expressing cytochrome P4501A2 cDNA. Transient expression of rat liver cytochrome P450lA2 cDNA was combined with the use of a shuttle vector as a mutational target to determine the frequency and types of mutation caused by the conversion of aflatoxin B1 into genotoxic metabolites within human cells. Ad293 cells were first transfected with p91-lA2, a rat liver P450lA2 cDNA expression vector, or with p91-lA2(i) (a control vector that has the P450 cDNA in the inverted orientation) and incubated for 24 h to permit P450lA2 accumulation. Cells were then transfected with the pS189 shuttle-vector plasmid, which carries the Escherichia coli supF gene as a mutational target, and incubated for a further 24 h in the presence of aflatoxin B1 to permit promutagen activation and pS189 replication. In shuttle vectors replicated in p91-lA2-transfected cells, the supF point-mutation frequency increased with increasing concentration of aflatoxin B1. This frequency was nine to 23 times greater than the background point-mutation frequency obtained with aflatoxin B1-treated control (p91-lA2(i)-transfected) cells. The large majority of the aflatoxin B1-induced supF point mutations were base substitutions, mostly G:C----T:A transversions. This mutagenesis system permits the molecular analysis of mutations induced by specific P450/promutagen pairs in a shuttle vector replicating in human cells and will permit the investigation of host cell mechanisms involved in the generation of these mutations.


Molecular cloning, analysis, and chromosomal localization of a mouse genomic sequence related to the human papillomavirus type 18 E5 region. The E5 open reading frame (ORF) from bovine papillomavirus type 1 (BPV 1) as well as the E5 ORFs from human papillomaviruses (HPV) type 6 and type 16 have been reported to transform immortalized rodent cells. In an analysis of murine and human tumors for the presence of putative papillomavirus-related sequences, we cloned amplified cellular sequences from the mouse cell line Eb that cross-hybridized with the E5 ORF of HPV 18. A 2.1-kb fragment termed HC1 was sequenced. In normal murine cells, it was present as a single-copy genomic sequence located on chromosome 8. A region of 213 nucleotides corresponded to the E5 gene (HC1 E5), based on the best alignments and on the presence of direct and inverted repeats bearing a central sequence motif. These structural elements are also present in the HPV 18 E5 ORF. HC1 E5 contained an ORF that was transcribed bidirectionally. The transcription in the E5 direction was enhanced in RNA obtained from organs and tumors from carcinogen-treated animals and C127 cells. The polypeptide deduced from the sequence was related to E5 proteins from genital papillomaviruses, to the putative product of the Q300 mouse gene, and to several viral and human growth factors. The data suggest that there may be several cellular counterparts to the viral E5 proteins.


Hormone-stimulated secretion of luteinization factor in porcine granulosa cells. Luteinization stimulator (LS) is an intrafollicular compound which was shown to be released by granulosa cells under in vitro conditions with stimulatory effects on immature granulosa cell differentiation. This study was undertaken to determine the effects of various endocrine agents which are involved in the regulation of ovarian function on LS secretion by porcine granulosa cells isolated from 5-8-mm follicles (LGC). Cell conditioned media (CM) obtained after the 4-day culture of LGC were tested in the culture of immature (small) granulosa cells (SGC). The activity of LS released into the LGC conditioned medium was estimated by measuring progesterone (P4) produced by SGC in the presence of CM. Stimulation of P4 secretion was observed after addition of media from cultures treated by LHRH (10(-4) mol.l-1), epinephrine (10(-5) mol.l-1), LH (1 microgram.ml-1), dbcAMP (0.5 and 2.0 micrograms.ml-1) or insulin (1.0-5.0 micrograms.ml-1). Norepinephrine (10(-5) and 10(-7) mol.l-1), estradiol (0.1 and 1.0 microgram.ml-1) and prolactin (0.1 and 1.0 microgram.ml-1) did not change steroidogenic activity of CM. Epinephrine and norepinephrine (10(-5) and 10(-7) mol.l-1), LH (1 microgram.ml-1), dbcAMP (2.0 microgram.ml-1) and estradiol (1 microgram.ml-1) alone enhanced P4 production by SGC, whereas LHRH (10(-3) and 10(-4) mol.l-1), insulin (1.0-5.0 microgram.ml-1) and prolactin (0.1 and 1.0 microgram.ml.-1) did not have any effect. These observations suggest that the process of LS secretion in developing follicles is subject to a specific hormonal control.


Effect of topical application of estradiol-17 beta and PGE2 on PGE-binding sites in the porcine endometrium. High- and low-affinity prostaglandin E2 (PGE2) binding sites were found on day 15 after estrus in the endometrium of cycling (Cy) and pregnant (Pr) gilts as well as gilts treated with intra-uterine Silastic beads containing estradiol-17 beta (E2) alone or in combination with PGE2 (E and PG gilts respectively) and inserted into the uterine lumen on day 10 of the cycle. The average apparent dissociation constants (Kd) and binding site concentrations (Bmax) for the high- and low-affinity sites were respectively (mean +/- SEM): 8.4 +/- 0.7 pM and 3.28 +/- 0.38 fmol/mg of protein and 5.3 +/- 0.8 nM and 71 +/- 9 fmol/mg of protein. Samples collected along the meso- and antimesometrial aspects did not differ (P greater than 0.05), although the low-affinity Bmax was higher on the antimesometrial aspect for Pr and Cy gilts only. No difference in Kd (P greater than 0.10) was found between treatments for high-affinity binding sites. For the low-affinity binding sites, Kd was higher for Pr compared to PG and E but not to Cy gilts (P less than 0.05). The high-affinity Bmax was higher (P less than 0.05) for PG, followed by E, Pr and Cy gilts (respectively: 5.50 +/- 0.26; 4.19 +/- 0.46; 1.78 +/- 0.40; 1.64 +/- 0.23 fmol/mg of protein), although Pr and Cy gilts were not different (P greater than 0.05). These results suggest that the localized presence of conceptuses in the uterus in early pregnancy does not markedly affect PGE binding sites but that intrauterine applications of Silastic beads containing E2 and PGE2 increase high-affinity Bmax and decrease low-affinity Kd.


Multiple enzymatic pathways involved in the metabolism of glyceryl trinitrate in Phanerochaete chrysosporium. A study of glyceryl trinitrate metabolism by a filamentous fungus, Phanerochaete chrysosporium, carried out with the 14C-labeled substrate, provides evidence for a multienzymatic system leading to di- and mononitrate derivatives. At least two independent enzymatic activities were detected in the cytosolic fraction: an aerobic glutathione S-transferase activity and an anaerobic NADPH-dependent soluble cytochrome P450-like activity. Other hemoproteins with enzymatic activities dependent upon the presence of NADPH or ferrous ions were also detected in the microsomal fraction. Electron paramagnetic resonance spectra characteristic of an interaction between a hemoprotein and nitric oxide appeared in these two subcellular fractions during the anaerobic metabolism of glyceryl trinitrate.


HIV-1 and HIV-2 infections in men attending sexually transmitted disease clinics in Abidjan, Côte d'Ivoire. (1) To determine the prevalence of HIV-1 and HIV-2 infections and associated risk factors in men attending Abidjan's three sexually transmitted disease (STD) clinics; (2) to examine the use of such sites for epidemiological surveillance. Cross-sectional study. Abidjan's two main STD clinics (Clinics A and T), and the University Hospital Dermatology outpatients clinic. Consecutive patients with genitourinary symptoms. Prevalence of reactivity to HIV-1, HIV-2, and both viruses; descriptive characteristics of clinic attenders; clinical diagnoses of STD; risk factors associated with HIV-1 and HIV-2 positivity. The overall prevalence of HIV (HIV-1 and/or HIV-2) infection was 21% (250 out of 1169; 16% HIV-1, 2% HIV-2, 3% dual reactivity). Overall prevalence varied by clinic: University Hospital Dermatology outpatients clinic, 39%; Clinic T, 19%; Clinic A, 10%. Men with STD had an overall prevalence of 31% (155 out of 506), compared with 14% in men without physical signs of STD (odds ratio 2.6, 95% confidence interval 2.0-3.6). The highest prevalence, 46%, was in men with genital ulcer disease. Risk factors associated with HIV-1 as well as with HIV-2 infection after multivariate analysis were a history of sex with prostitutes, lack of circumcision, being unskilled, and a history of prior genital ulcer. Current genital ulcer, current STD and positive Treponema pallidum haemagluttination assay were associated with HIV-1 and dual reactivity. Risk factors for HIV-2 infection in men attending Abidjan STD clinics were broadly similar to those for HIV-1 infection. HIV-1 infection was more strongly associated with current STD. Important differences between the three clinics were observed in STD prevalence and type, and HIV seroprevalence. Such differences should be taken into account in the planning of HIV serosurveillance in STD clinics.


HIV-1 in postmortem brain tissue from patients with AIDS: a comparison of different detection techniques. The presence of HIV-1 in postmortem brain tissue from 31 patients with AIDS and 12 HIV-1-negative controls was investigated. Most laboratories have access to the methods used. We readily applied in situ hybridization and immunohistochemistry to archival formalin-fixed paraffin-embedded (FFPE) brain specimens. The techniques used to detect HIV-1 were explant culture, in situ hybridization with 35S-labeled polymerase (pol) gene riboprobes and immunohistochemistry with monoclonal antibody to gp41. HIV-1 was isolated from explant cultures in 13 out of 20 (65%) patients, whereas HIV-1-infected cells were detected in FFPE brain tissue from nine out of 26 (35%) patients examined by in situ hybridization and in seven out of 26 (27%) patients examined by immunohistochemistry. Although the isolation technique was the most sensitive of the three techniques tested, infected cells may be identified with in situ hybridization in conjunction with immunohistochemistry.


Enhanced inhibitory effect of alpha 2-adrenoceptor stimulation on the formation of cAMP in glomeruli of spontaneously hypertensive rats. Renal alpha 2-adrenoceptors are known to be increased in spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto rats (WKY). To investigate whether this difference affects the second messenger system, we examined the effect of alpha 2-adrenoceptor stimulation on the formation of cAMP in microdissected glomeruli and proximal convoluted tubules obtained from the kidneys of SHR and WKY. The formation of glomerular cAMP, which was stimulated by parathyroid hormone (PTH), was inhibited by alpha 2-adrenoceptor stimulation. In contrast, the inhibitory effect of alpha 2-adrenoceptor stimulation on PTH-induced cAMP formation in proximal convoluted tubules was not significantly different between SHR and WKY. These results confirm the inhibitory action of alpha 2-adrenoceptors on the formation of cAMP in glomeruli and proximal tubules and suggest that the greater inhibitory effect on glomerular cAMP formation in SHR may reflect an increase in alpha 2-adrenoceptor density in SHR kidneys.


Effect of dietary sodium intake on intracellular calcium in lymphocytes of salt-sensitive hypertensive patients. High dietary Na+ raises mean arterial pressure (MAP) by more than 10% in salt-sensitive (SS) patients with essential hypertension. To test whether the rise in MAP in these patients is caused by a Na(+)-linked increase in [Ca2+]i in vascular smooth muscle cells, we measured [Ca2+]i in the lymphocytes of 14 patients with essential hypertension kept on a Na+ intake of 20 mEq/day for 9 days, and 200-mEq/day for 14 days. Nifedipine gastrointestinal transport system (GITS) (30 mg/day) was given during the last 4 days of each diet. We isolated lymphocytes on Ficoll-Hypaque gradient and measured [Ca2+]i levels using Fura-2 fluorescent dye. During low Na+ intake, there was no difference in MAP (102 +/- 3.5 v 93 +/- 3.8 mm Hg) and in lymphocytes [Ca2+]i (80 +/- 3.0 v 87 +/- 5.4 nmol/L) between the seven salt-sensitive and the seven salt-resistant patients. During high Na+ intake, MAP (92 +/- 2.8 mm Hg) and [Ca2+]i (85 +/- 6.8 nmol/L) did not change in salt-resistant patients. On the contrary, MAP (115 +/- 3.4 mm Hg) and [Ca2+]i (130 +/- 11.1 nmol/L) increased significantly (P less than .01) in the salt-sensitive patients. Nifedipine did not significantly alter MAP and [Ca2+]i in both groups of patients during low Na+ and in salt-resistant patients during high Na+ intake. On the contrary, during high Na+ intake, nifedipine decreased significantly (P less than .01) both MAP (104 +/- 2.4 mm Hg) and [Ca2+]i (89 +/- 5.7 nmol/L) in salt-sensitive patients.(ABSTRACT TRUNCATED AT 250 WORDS)


Modification by oxazepam of the diurnal variations in brain 125I-melatonin binding sites in sham-operated and pinealectomized rats. Sham-operated and pinealectomized male rats were maintained at 14 h light:10 h dark cycles (lights-on 5.00 h) and injected daily, for 14 days, with oxazepam or vehicle. 125I-melatonin binding was recorded in synaptosomes prepared at 10.00, 18.00, and 24.00 h from the hypothalamus, hippocampus and medulla-pons of the rats. In the sham-operated, vehicle treated rats, specific 125I-melatonin binding in all brain areas studied was higher at 18.00 h, whereas in the oxazepam-treated animals, binding was higher at 24.00 h than at the other times tested. In the pinealectomized, vehicle-treated rats, the binding recorded at 18.00 h in all three brain areas, was lower than at the other times of day tested. Oxazepam treatment decreased 125I-melatonin binding at 24.00 h in the hippocampus and medulla-pons of the pinealectomized rats and did not significantly affect the binding in the hypothalamus. These results indicate the ability of oxazepam, pinealectomy and their combination, to manipulate the diurnal variations in 125I-melatonin binding sites in the rat brain.


Erythrocyte membrane sodium-potassium adenosine triphosphatase activity in affective disorders. Erythrocyte membrane Na+,K(+)-ATPase activity was studied in drug naive patients with bipolar (BP) mania (n = 62) and unipolar (UP) depression (n = 60) and normal controls (n = 66). Compared to controls there was a significantly decreased Na+,K(+)-ATPase activity in UP depressives but no change in BP manics. However, lithium treatment caused a significant increase in Na+,K(+)-ATPase activity although there was no correlation between plasma lithium levels and enzyme activity. Plasma cortisol correlated inversely with Na+,K(+)-ATPase in UP depressives. Interestingly, the lithium responders [less than 50% Beck Rafaelson's Mania Rating Scale (BRMS) score] showed a significant increase in Na+,K(+)-ATPase activity compared to lithium nonresponders (greater than 50% BRMS score). These observations indicate that monitoring of Na+,K(+)-ATPase activity during lithium therapy is useful to predict a therapeutic response.


Rotavirus infection in Tanzania: a virological, epidemiological and clinical study among young children. Rotavirus infection in the Dar es Salaam area of Tanzania was studied in 99 hospitalized children with acute diarrhoea and 99 hospitalized non-diarrhoea referents matched for sex and age. Of the diarrhoea cases 43.4% had rotavirus in the stools as opposed to 15.2% of the referents. The high carrier rate among the referents represents a serious risk of nosocomial transmission. More referents than cases had serum IgG antibodies to rotavirus, 52.5% and 35.4%, respectively (P < 0.02), while there was no correlation with serum IgM and IgA or faecal IgA antibodies. The latex agglutination test had a sensitivity comparable to that of electron microscopy (100%) and a specificity of 93.8%. The Slidex test appeared to be superior to the Rotalex test in that it gives very few false-positive reactions. The SDS-PAGE patterns of 11 RNA segments were compatible with the presence of group A strains with considerable heterogeneity among the strains. Symptoms and signs and some environmental data were recorded. None of them was clearly associated with rotavirus infection among the diarrhoea cases. It is concluded that rotavirus is a major cause of acute infectious diarrhoea in Tanzania.


Melanotic neuroectodermal tumour as a predominant component of an immature testicular teratoma. Case report with immunohistochemical investigations. A case of melanotic neuroectodermal tumour (MNT), or so-called retinal anlage tumour, as a predominant component of an immature testicular teratoma is presented. The patient was a 17-year-old man who furthermore had a mature mediastinal teratoma. The MNT was composed mainly of two cell types: small immature neuroblast-like cells and large columnar or cuboidal epithelial-like cells with or without melanin granules. The tumour cells were arranged in solid formations, nests, cords, alveolar and pseudoglandular structures with cleft-like or glomeruloid-like spaces. Myogenic differentiation was found in minor foci. Immunohistochemistry showed both neuroepithelial and mesenchymal features with positive staining reaction for neuron-specific enolase (NSE), S-100 protein (S-100), melanoma antigen (HMB45), cytokeratin and vimentin. Vimentin, desmin and actin were present in the myoid cells. To the best of our knowledge this is the first reported case of MNT originating in the testis. As this tumour component occurred in an immature teratoma, neuroectodermal differentiation of germ cell origin is considered most likely.


Enzymatic inverse PCR: a restriction site independent, single-fragment method for high-efficiency, site-directed mutagenesis. A new method is described for rapid site-directed mutagenesis of plasmid DNA. The new method, termed enzymatic inverse polymerase chain reaction (EIPCR), uses inverse PCR to amplify the entire plasmid. The key step to EIPCR is the incorporation of identical class 2s restriction sites in both primers. Class 2s restriction enzymes have a recognition site that is located 5' of the cut site (e.g., BsaI: GGTCTCN'NNNN,). Thus, after completing PCR, the ends of the full-length linearized plasmid are digested with the class 2s enzyme incorporated into the primers. The enzyme cuts off its entire recognition site and leaves the plasmid with compatible overhangs on both ends. Thus, in the ligation the only part that becomes part of the plasmid is the NNNN overhang, which can be made to be the native sequence. We have used the method for many plasmids and several class 2s enzymes. As an example, we report here the use of EIPCR for an insertion into pUC19 containing an inactive lacZ alpha-peptide, causing a frameshift that restores lacZ alpha-activity. Of 300 colonies evaluated, greater than 95% had the expected blue phenotype. The BsaI overhangs were correctly combined in all of the 35 blue colonies analyzed by restriction digestion and in all four clones that were sequenced. EIPCR is compared with four related PCR-based mutagenesis techniques. The major advantage of EIPCR over the other methods is the combination of greater than 95% correctly mutated clones with the need for only two PCR primers.


Chemiluminescent detection of DNA on nylon membranes. Two types of nonradioactive DNA detection systems were optimized for use with nylon membranes in Southern transfers. A luminol substrate system (consisting of an enhanced chemiluminescent reaction utilizing luminol enzyme substrate) was used with peroxidase-labeled probe DNA, and a dioxetane-based substrate was used with alkaline phosphatase/antibody and digoxigenin-labeled probe DNA. Chemiluminescence was detected by autoradiography. Methods for reprobing the membranes were also optimized for both systems; blots could be reprobed at least ten times. Results showed that excellent sensitivity and low background can be achieved on both amphoteric and positively charged nylon membranes, using either detection system.


Improved electrophoretic separation of supercoiled and relaxed DNA in the presence of ethidium bromide. Supercoiled and relaxed DNA were resolved electrophoretically in the presence of 0.5 micrograms/ml ethidium bromide. Under these conditions the Gaussian distributions of topological isomers of both supercoiled and relaxed DNA migrated as discrete bands. The separation of these DNAs was optimized by varying the concentration of electrode buffer. Electrophoresis in the presence of 160 mM Tris-acetate, pH 8.3, 4 mM EDTA resulted in a 20-fold increase in the separation of relaxed and supercoiled DNA relative to electrophoresis in 40 mM Tris-acetate, pH 8.3, 1 mM EDTA.


Transforming growth factor-alpha gene expression in the hypothalamus is developmentally regulated and linked to sexual maturation. Hypothalamic injury causes female sexual precocity by activating luteinizing hormone-releasing hormone (LHRH) neurons, which control sexual development. Transforming growth factor-alpha (TGF-alpha) has been implicated in this process, but its involvement in normal sexual maturation is unknown. The present study addresses this issue. TGF-alpha mRNA and protein were found mostly in astroglia, in regions of the hypothalamus concerned with LHRH control. Hypothalamic TGF-alpha mRNA levels increased at times when secretion of pituitary gonadotropins--an LHRH-dependent event--was elevated, particularly at the time of puberty. Gonadal steroids involved in the control of LHRH secretion increased TGF-alpha mRNA levels. Blockade of TGF-alpha action in the median eminence, a site of glial-LHRH nerve terminal association, delayed puberty. These results suggest that TGF-alpha of glial origin is a component of the developmental program by which the brain controls mammalian sexual maturation.


Tumor necrosis factor-alpha and interleukin-1 alpha synergistically enhance phorbol myristate acetate-induced superoxide production by rat bone marrow-derived macrophages. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) are secreted by macrophages in response to endotoxin challenge. In addition, macrophages express receptors for both of these cytokines. Macrophage function can therefore be modulated by regulation of both cytokine production and receptor levels. We have initiated studies to investigate the effects of TNF-alpha and IL-1 alpha on macrophage function. Macrophages were obtained by in vitro differentiation of rat bone marrow cells. The biologic response to TNF-alpha and IL-1 alpha was assessed by measurement of superoxide production quantitated by the reduction of cytochrome c in response to phorbol myristate acetate. Macrophages were treated with endotoxin (LPS), TNF-alpha, and IL-1 alpha, alone and in combination. None of these agents was a primary stimulus for superoxide production. However, after treatment with endotoxin or TNF-alpha for 24 h, macrophages were primed for enhanced production of superoxide. The priming effect of LPS was due, at least in part, to endogenously produced TNF-alpha, since anti-murine TNF-alpha antibodies blocked the LPS-mediated priming by approximately 30%. IL-1 alpha did not prime macrophages, but treatment with IL-1 alpha followed by TNF-alpha or LPS resulted in enhanced superoxide production. IL-1 alpha treatment of macrophages resulted in an increase in TNF-alpha receptors, which might explain the synergistic priming of TNF-alpha and IL-1 alpha.


Prolonged transgene expression in rodent lung cells. We tested the efficiency of several different cationic liposome formulations, complexed to one of two different chloramphenicol acetyltransferase (CAT) reporter plasmids, in transfecting freshly isolated, highly purified rat lung alveolar type II cells, alveolar macrophages, and three different human lung carcinoma cell lines, as well as NIH 3T3 cells, a rapidly dividing, transformed mouse fibroblast line. Our results demonstrated that several different cationic liposome formulations can mediate high-level CAT gene expression in all the cell types tested. Electron microscopic analysis confirmed that cationic liposome-DNA complexes are avidly bound and internalized by lung cells. The time course of expression of transfected genes in nontransformed cell types with low mitotic indices, such as type II cells, is poorly characterized. NIH 3T3 cells expressed maximal CAT activity by day 4 following transfection, with virtual disappearance of activity by day 11. Conversely, type II cells expressed maximal CAT activity between days 5 and 11, and CAT activity was still clearly present 35 days after transfection. Southern blot analysis of DNA isolated from transfected type II cells revealed that the CAT gene was largely present in an extrachromosomal form, rather than integrated into genomic DNA. These observations indicate that following cationic liposome-mediated transfection, rat alveolar type II cells (the majority of which do not divide in culture) can express transfected genes for prolonged periods, apparently mediated by expression of the transgene in an episomal form.


[Treatment of infantile spasms with long-term low dose ACTH]. We investigated the effect of long-term, low-dose ACTH in 13 patients (10 boys and 3 girls) with infantile spasms who were treated with low-dose ACTH (mean: 0.0081 mg/kg/day). Two patients (one boy and one girl) received this therapy twice because of relapse of tonic spasms. ACTH was injected intramuscularly every morning for 30 days, after which dosage was tapered. The mean observation period was 53.9 months. Complete cessation of seizures was attained in 13 of 15 treatment trials. In one trial, complete cessation was not attained but the number of attacks decreased to less than one-third of that before treatment. In only one trial was treatment not effective. EEG showed good response to this treatment. The side-effects of this therapy were hypertension in 6 patients, hypokalemia in 7, and emotional outburst in 7. Emotional outburst appeared during the early phase of therapy, while the other two side-effects appeared in the later phase and disappeared when ACTH-tapering was begun. Brain shrinkage observed on CT scan was mild in all trials. Five patients have had no relapse. The total dose of ACTH was significantly larger in the group with good outcome than in the group with poor outcome.


Fireside conference 11. Common cold.

Fireside conference 11. Common cold. The accepted concept that cold symptoms are usually caused by destruction of the nasal epithelium by virus and that epithelial damage may led to secondary bacterial infection is not supported by this work. Although influenza and adenovirus may destroy the epithelium, no destruction of the nasal epithelium was detected either in vivo during natural or rhinovirus cold on in-vitro in nasal epithelial organ cultures. Infiltration of the nasal mucosa with neutrophils early in the cold does not indicate bacterial infection but may be a direct result of the viral infection. Purulent nasal secretions, which are common in uncomplicated colds, were not accompanied by discernible changes in the aerobic bacterial flora. The nasopharynx may be an important area for further exploration in the study of the pathogenesis of rhinovirus infection since it is a site to which mucus containing virus from the entire nasal mucosa is brought. A prominent feature of the posterior nasopharyngeal wall in both children and adults is a mass of mucosa-associated lymphoid tissue (adenoid or nasopharyngeal tonsils). Preliminary data has suggested that the epithelium overlying the lymphoid tissue expresses ICAM-1 receptors in the normal state, whereas the nasal epithelium does not. This is interesting since the majority of rhinovirus serotypes gain entrance to human cells by this receptor. Symptoms in a rhinovirus cold could result from release of inflammatory and/or neuromediators from the adenoid. Recently, Naclerio et al (8) have demonstrated that kinins and an increased number of neutrophils in nasal secretions correlate with occurrence of symptoms in volunteers with rhinovirus colds.


Intraoperative transesophageal echocardiographic localization of tumor embolus during pneumonectomy. We describe a patient undergoing pneumonectomy for large-cell carcinoma, which at the time of surgery was found to invade the pulmonary veins. Transesophageal echocardiography was used to confirm and localize suspected tumor embolization during surgery. Although tumor embolization from the pulmonary veins has been previously reported in the literature, this is the first case, to our knowledge, of transesophageal echocardiographic documentation of such an occurrence. The use of echocardiography in patients at potential risk for tumor involvement of the pulmonary veins is discussed.


Epirubicin in previously untreated patients with small cell lung cancer: a phase II study by the EORTC Lung Cancer Cooperative Group. Epirubicin 110 mg/m2 was administered intravenously every 3 weeks to 41 elderly and/or unfit, previously untreated patients with small cell lung cancer (SCLC). There were three complete responses, 16 partial responses and 14 treatment failures, with a response rate of 57% in 33 evaluable patients. The main toxicity was haematological, characterised by leukopenia and, less frequently, thrombocytopenia and anaemia. There were three toxic deaths due to infection occurring during leukopenia. Non-haematological side effects were alopecia, nausea, stomatitis and diarrhoea. WHO grade 2 cardiac toxicity was seen in 3 patients after a cumulative dose of more than 740 mg/m2. In conclusion epirubicin is an active agent in untreated SCLC.


Photodynamic therapy.

Photodynamic therapy. Photodynamic therapy (PDT) has been developed over the past decade into a useful treatment for several types of solid cancers in man. This unique therapy requires a photosensitiser accumulated in tumours and local activation by visible light generally delivered from lasers and delivered to the patient through various types of fibers and endoscopes. PDT appears to be most effective in treating certain superficial, difficult to treat cancers such as carcinoma in situ of the urinary bladder (here complete control is the intent), but also is effectively used in bulkier tumours obstructing bronchi or the oesophagus where palliation can be achieved. The primary mechanism of action is the in situ generation of an active form of molecular oxygen (singlet oxygen) which causes the rapid, local onset of vascular stasis and eventual vascular haemorrhage and tumour wall destruction. This process appears to be mediated through various cytokines such as prostaglandin, lymphokines and thromboxanes. The ultimate clinical value of PDT will be seen over the next few years following health agency approval worldwide.


Vincristine is associated with the risk of azoospermia in adult male survivors of childhood malignancies. Of 55 males, currently above 18 years of age, diagnosed with and treated for different malignancies in childhood between 1960 and 1985 at a single institution, 28 (51%) were azoospermic. The age of the patient, testicular irradiation, four different therapeutic agents (L-asparaginase, cyclophosphamide, doxorubicin, vincristine) and one combination (MOPP, nitrogen mustard, vincristine, procarbazine, prednisone) were each associated with the risk of azoospermia. However, in multivariate analysis vincristine had the statistically most significant independent effect on the risk of azoospermia, the risk being 5-fold (95% confidence limits 1.3-18.8, P = 0.02) that in patients who had not received vincristine. The risk of azoospermia in patients who had received cyclophosphamide was 3.4-fold (0.95-12.3, P = 0.06) and in those who had received testicular irradiation it was 8.2-fold (0.75-90.9, P = 0.09) that of others. Normospermia (22% of patients) was not incompatible with any of the more commonly used modes of therapy. We conclude that vincristine may have a previously unrecognised important role in causing azoospermia, possibly irreversible, when administered in childhood or adolescence.


Phase I-II study of vinorelbine (Navelbine) plus cisplatin in advanced non-small cell lung cancer. 32 patients with advanced non-small cell lung cancer previously untreated by chemotherapy were included in a phase I-II study in order to determine the feasibility of the combination of vinorelbine and cisplatin, each administered at its optimal dose, i.e. 30 mg/m2 weekly and 120 mg/m2 every 4-6 weeks, respectively. There were 27 males and 5 females with a mean age of 55 years and a median performance status of 80%. 13 had locally advanced disease and 19 had distant metastases at the time of inclusion. Our study demonstrated the feasibility of this protocol. Dose intensities could be maximised by adapting vinorelbine doses rather than by postponing treatment in the event of neutropenia. Both response rate (33%) and overall survival of the population (median 11 months) justify further studies.


[Gastroesophageal infection caused by cytomegalovirus in immunodepressed patients. Presentation of 3 cases]. We report three cases of upper gastrointestinal infection by Cytomegalovirus in immunocompromised patients. Two patients suffered from AIDS and the other one had a recent heart transplantation and was on immunodepressant drugs for an episode of rejection. The stomach in two cases and the esophagus in the other were the affected organs. In all cases there were upper gastrointestinal symptoms and the diagnosis was established by biopsy of endoscopically suspicious lesions. Antiviral therapy was effective in all three cases. This diagnosis has to be considered whenever immunocompromised patients present with unusual clinical and endoscopic findings.


Calcified bladder tumors. CT features.

Calcified bladder tumors. CT features. CT scans of the pelvis in 132 patients with bladder tumor were reviewed. Calcifications in the bladder tumor were found in 11 men (8%) including transitional cell carcinoma (n = 6), mucinous adenocarcinoma (n = 4), and malignant mixed mesodermal tumor (n = 1). Calcifications in transitional cell carcinoma were located on the surface of the tumor in all 6 cases: they were nodular in 4 cases, nodular and arched in one, and plaque-like massive calcification in one. In mucinous adenocarcinoma multiple fine punctate calcifications were scattered within the mass in all 4 cases. The CT appearance of calcifications in bladder tumors may be helpful in predicting the histologic type of the tumor.


P-31 MR spectrum and histologic changes after intrahepatic arterial injection of iodized oil in normal and cirrhotic rat liver. Injection of iodized oil (Lipiodol) into the hepatic artery is widely used in the diagnosis and treatment of hepatocellular carcinoma. However, no reports have yet appeared concerning temporal changes in hepatic metabolism following Lipiodol injection. In the present study, Lipiodol was injected into the hepatic arteries of normal and cirrhotic rats, successive P-31 MR measurements were performed, and temporal changes in metabolism were compared with histologic findings. Both normal and cirrhotic rats displayed minimum levels of beta-ATP/PME and beta-ATP/Pi 5 days after hepatic arterial injection of Lipiodol. However, 10 days after injection these values had reverted to the preinjection levels. The metabolic dysfunction observed in the liver following hepatic arterial injection of 0.3 ml/kg b.w. Lipiodol was transient. Moreover, no distinct differences were observed between P-31 MR changes in normal and cirrhotic rats. Conversely, histologic impairment assessed on the basis of hepatic necrosis ratios was most severe 2 days after hepatic arterial injection in both normal and cirrhotic rats, and this did not coincide with the time of the most pronounced metabolic impairment as inferred from P-31 MR changes.


Necrosis observed on CT enhancement is of prognostic value in soft tissue sarcoma. Fifty-one patients with deep-seated soft tissue sarcoma of the extremities and trunk wall were examined with contrast-enhanced CT for presence of nonenhanced tumor areas (CT necrosis). After a median follow-up time of 3 years, 19 of the 41 patients with CT necrosis had developed metastases, compared to none of the 10 patients who had tumors without CT necrosis. Tumors with CT necrosis were larger than tumors without, but in tumors of similar size, absence of CT necrosis was a favorable prognostic sign.


Epidermal growth factor receptor monoclonal antibodies inhibit the growth of lung cancer cell lines. The ability of monoclonal antibody (MAb 108), an immunoglobulin G (IgG)2a against the epidermal growth factor receptor (EGF-R), to interact with lung cancer cell lines was investigated. 125I-EGF bound with high affinity to non-small-cell lung cancer (NSCLC) cells, and MAb 108 inhibited specific binding of nine NSCLC cell lines in a dose-dependent manner (IC50 = 0.3-3 micrograms per ml). 125I-MAb 108 bound with high affinity (kd = 2 nM) to a single class of sites (Bmax = 70,000 per cell) using NSCLC neuroendocrine cell line NCI-H460. Specific 125I-MAb 108 binding was inhibited with high affinity by MAb 108 but not by a control antibody IgG using large-cell carcinoma cell line NCI-H1299. 125I-MAb 108 binding was not internalized at 37 degrees C using NSCLC neuroendocrine cell line NCI-H460 and adenocarcinoma cell line NCI-H23. Also, 1 microgram per ml of MAb 108 but not of a control IgG inhibited the clonal growth of NCI-H23 and squamous cell carcinoma cell line NCI-H157 in vitro. Also, MAb 108 inhibited xenograft formation of cell lines NCI-H460, NCI-H157, and NCI-H727 in nude mice in vivo. After a palpable tumor had formed using NCI-H460 cells, injection of 100 micrograms of MAb 108 (intraperitoneally three times weekly) inhibited xenograft volume in nude mice by approximately 50%. These data suggest that MAb 108 may interact with EGF receptors on lung cancer cell lines and inhibit NSCLC proliferation.


Molecular genetic analysis of two distinct receptors for mammalian bombesin-like peptides. The mammalian bombesin-like peptides are known to be growth factors for certain cells with high-affinity bombesin receptors and have been implicated as autocrine growth factors influencing the pathogenesis and progression of a subset of human small-cell lung carcinomas. Thus, antagonists that interfere with bombesin receptor-ligand interaction might prove to be of value in treatment of gastrin-releasing peptide (GRP)-responsive tumors. A precise definition of the structure and properties of the bombesin receptors found on human lung cancer cells would provide important information for the design and rational application of such antagonists. Recently, we isolated cDNA clones encoding two distinct receptors for the mammalian bombesin-like peptides, GRP, and neuromedian B (NMB). The two receptors show 56% amino acid identity, encode seven putative transmembrane domains, and are members of the G-protein-coupled receptor superfamily. Ligand-binding studies show that while both receptors can be activated by either GRP or NMB, one receptor has a higher affinity for GRP than for NMB (GRP-R), while the other has a higher affinity for NMB than for GRP (NMB-R). A different spectrum of antagonists is needed to block responses from the two different receptors. These studies indicate that it will be critical in future studies to define which bombesin receptor subtypes are present on a given tumor to optimize the potential therapeutic benefit of antagonists in blocking growth.


Molecular approaches to prevention and therapy of aerodigestive tract cancers. We describe studies defining several molecular events in human non-small-cell lung cancer (NSCLC). These include increased growth factor and growth factor receptor expression and oncogene alterations. The epidermal growth factor receptor (EGFR) and erbB2 are expressed by NSCLC cells. Transforming growth factor-alpha (TGF-alpha) is produced by NSCLC and may mediate autocrine growth stimulation. Specific inhibition of K-ras oncogene expression by an antisense K-ras construct reduces the growth rate and tumorigenicity of NSCLC cells. Studies with antisense p53 in NSCLC with a homozygous p53 mutation suggest that the presence of the mutant form contributes to the transformed state.


Association between histological type and neuroendocrine differentiation on drug sensitivity of lung cancer cell lines. Because most small-cell lung cancers (SCLC) are initially chemosensitive and express neuroendocrine (NE) cell markers and most non-SCLC tumors (NSCLC) are chemoresistant and do not express NE cell markers, we investigated the association between morphological type and NE cell differentiation with in vitro chemosensitivity. We tested a panel of 55 lung cancer cell lines established from previously untreated patients. These were tested against five cytotoxic drugs commonly used in the therapy of lung cancer, using the MTT assay. For comparative purposes, we also tested cell lines established from previously treated patients with SCLC and from colorectal tumors. The logarithms of the IC50 values of all of the cell lines were normally distributed, permitting the use of Student's t-test for assessment of differences. In general, the in vitro sensitivities of SCLC, NSCLC, and colorectal cell lines mirrored the clinical experience with these tumor types. Cell lines started from previously treated patients with SCLC were more resistant than those from previously untreated patients who responded to initial therapy. For all of the cell lines, the sensitivities to the five drugs tested were highly significantly correlated with each other. Thus, for comparative purposes, each group could be assigned an average standardized mean rank. About 15% of NSCLC tumors express multiple neuroendocrine (NE) cell markers and 4 of 5 lines from these NSCLC-NE tumors were relatively chemosensitive, similar to SCLC lines and significantly different from other NSCLC lines. Other NE cell lines tested included bronchial carcinoids and cell lines from small-cell carcinomas arising in extra-pulmonary locations (ExPuSC).(ABSTRACT TRUNCATED AT 250 WORDS)


Combination immunotherapy for advanced lung cancer. Therapeutic strategies using cytokines have not been extensively tested in patients with advanced non-small-cell lung cancer (NSCLC). We developed a basic laboratory and clinical research program to investigate the effective immunotherapeutic manipulations for activating the endogenous immune system with biological agents. Our efforts using low-dose interleukin 2 in conjunction with other biologic response modifiers for the treatment of NSCLC are summarized here.


The ras gene family in human non-small-cell lung cancer. The three ras genes code for proteins with a putative role in cellular signal transduction. They belong to a larger family of small guanosine-triphosphate (GTP)-binding proteins. The ras proteins acquire transforming activity when amino acids are substituted at one of a few specific sites, as a result of a point mutation in the gene. In about one third of adenocarcinomas of the lung, a K-ras mutation is present in codon 12 of the gene. Patients with early stages of K-ras mutation-positive tumors have a very unfavorable prognosis, even if apparently radical resection of the tumor has taken place. K-ras mutations are very rare among nonsmokers, and it is reasonable to assume that carcinogens in tobacco smoke directly cause the mutation. The types of ras mutations found in lung cancer are different from those in gastrointestinal malignancies. Colon cancer is mainly associated with mutations leading to substitution of the normal glycine at amino acid position 12 of K-ras by either valine or aspartic acid, and mutations in N-ras are not exceptional. In contrast, the predominant mutation in lung cancer leads to substitution of cysteine in codon 12. Several other members of the ras gene superfamily are also expressed in human lung cancer, but a possible relationship with lung tumorigenesis remains to be established.


myc family DNA amplification in tumors and tumor cell lines from patients with small-cell lung cancer. The myc family DNA copy number of 291 specimens (183 tumors and 108 tumor cell lines) from patients with small-cell lung cancer has been reported in 15 different studies. Thirty-five of 108 (32%) cell lines from small-cell lung cancer patients have myc family DNA amplification (16 c-myc, 7 N-myc, and 12 L-myc). Thirty-seven of 183 (20%) tumors from patients with small-cell lung cancer have myc family DNA amplification (3 c-myc, 13 N-myc, and 18 L-myc). The myc family DNA copy number in tumors from patients with small-cell lung cancer is similar in the majority of sites from the same patient. The presence of myc family DNA amplification in the tumor cell line is also typically present in the tumor from the same patient. myc family DNA amplification is present in a minority of patients with small-cell lung cancer, and the data on its association with shorter survival of patients are meager at present. Future studies on the biology of the myc family in small-cell lung cancer may require use of newer technologies that can work with small tissue samples typically available at the start of therapy.


Expression of surfactant-associated protein in non-small-cell lung cancer: a discriminant between biologic subsets. We examined expression of the major surfactant-associated protein SP-A, a product characteristic of type II pneumocytes, in a panel of 126 non-small-cell lung carcinomas (NSCLC) by immunohistochemistry using routine paraffin-embedded material. In nonneoplastic lung, the expression was seen in normal and reactive type II pneumocytes. Based on a defined staining index composed of the number of cells and the staining intensity, 32% of all the NSCLC revealed SP-A immunoreactivity that was mostly focal. The highest incidence (50%) was demonstrated in adenocarcinomas having papillolepidic growth patterns (which include the bronchioloalveolar and papillary subtypes), followed by other subtypes of adenocarcinomas (31%) and other types of NSCLC (14%). Patients with SP-A expressing tumors had male/female ratio 1.1, as compared to 2.2 in all NSCLC or 2.0 in papillolepidic tumors. SP-A immunoreactivity in tumors was associated with lighter smoking history, significantly so in men (P2 = .016). The finding of a marker characteristic of peripheral, alveolar cell differentiation in all adenocarcinomas is of interest and supports the concept of common pathogenesis for adenocarcinomas. We conclude that SP-A expression occurs predominantly, but not exclusively, in adenocarcinomas, particularly in those with papillolepidic growth pattern. SP-A expression may delineate biologically and clinically interesting subsets of NSCLC.


Control of squamous differentiation in tracheobronchial and epidermal epithelial cells: role of retinoids. Hyperplasia and squamous differentiation in epidermal and tracheobronchial epithelial cells is a multistage process. In stage I, quiescent progenitor cells are recruited to reenter the cell cycle. Protein kinase C activators, retinoids, cytokines, and polypeptide growth factors have been identified to control this stage of hyperproliferation. In stage II, cells become committed to irreversible growth arrest, which in normal cells appears to be a prerequisite for the expression of the differentiated phenotype (stage III). Confluence or treatment with interferon gamma or phorbol esters are conditions that induce irreversible growth arrest and differentiation. Retinoids do not block stage II but specifically suppress the expression of stage III. The action of retinoids appears to be mediated by nuclear retinoic acid receptors. Studies understanding the mechanisms that regulate hyperplasia and squamous metaplasia may provide insight into the processes that lead to squamous cell carcinomas. Such studies may also provide new strategies for chemotherapy and chemoprevention.


HLA-DR antigen linkage of anti-beta receptor antibodies in idiopathic dilated and ischaemic cardiomyopathy. Immunological mechanisms have been implicated in the pathogenesis of human dilated cardiomyopathy. The presence of autoantibodies against the beta 1 adrenoceptor in a substantial proportion of patients with dilated cardiomyopathy has been described and an association between the HLA-DR4 phenotype and anti-beta receptor antibodies has been identified. The objective of the present study was to examine whether the presence of such antibodies in ischaemic cardiomyopathy was limited to specific HLA-DR phenotypes. The HLA-DR dependence of anti-beta receptor antibodies detected by a ligand binding inhibition assay in patients with dilated cardiomyopathy (n = 68) was compared with that in patients with ischaemic cardiomyopathy (n = 73). 38% of the patients with dilated cardiomyopathy and 22% of those with ischaemic cardiomyopathy had serum anti-beta receptor antibodies. In dilated cardiomyopathy, the presence of anti-beta receptor antibodies was linked to the HLA-DR4 phenotype (that is, 50% of patients with this phenotype were antibody positive) whereas, in those with ischaemic cardiomyopathy HLA-DR1 was over-represented (that is, 37% of the patients with the HLA-DR1 phenotype were antibody positive compared with 17% of the HLA-DR1 negative patients). In both disease entities, the HLA-DR3 phenotype was virtually absent in the anti-beta receptor antibody group. These results suggest that the presence of anti-beta receptor antibodies is under immune genetic control that may depend on the nature of the underlying disease process.


Influence of cardiopulmonary bypass on water balance hormones in children. To determine the changes in the endocrine mechanisms of fluid balance after cardiopulmonary bypass in children. Prospective study; analysis of numbered plasma samples performed blind with respect to clinical data. Regional paediatric cardiothoracic unit. Nine patients, median age 4, range 2 to 9 years, five males. Patients under the age of 1 year were excluded because of the frequent blood sampling involved. Plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin, plasma renin activity, aldosterone, noradrenaline and adrenaline, and urinary concentrations of cyclic guanosine monophosphate (cGMP) as measured by radioimmunoassay. After 30 minutes of cardiopulmonary bypass plasma atrial natriuretic peptide (ANP) decreased from (mean (SEM)) 151 (71) pg/ml to 52 (44) pg/ml (NS), and urinary production of its second messenger cyclic guanosine monophosphate (cGMP) decreased from 1286 (600) pmol/ml to 151 (414) pmol (p < 0.05). Other plasma concentrations of hormones studied did not change significantly although arginine vasopressin, adrenaline, and noradrenaline increased whereas aldosterone and plasma renin activity decreased. After cardiopulmonary bypass stopped there was an immediate and significant rise in plasma ANP, but within the next 24 hours plasma ANP declined significantly (p < 0.05), decreasing from 294 (49) pg/ml to 64 (29) pg/ml at 22 hours. In the postoperative period there was a significant correlation between plasma ANP and both mean fluid balance (r = 0.96, p < 0.001) and mean urine output (r = 0.97, p < 0.001). Plasma aldosterone peaked (p < 0.05) at 22 hours after operation, and argine vasopressin peaked (p < 0.05) at two hours and then declined (p < 0.05) to a trough at 24 hours. Plasma renin activity, adrenaline, noradrenaline, and urinary cGMP concentrations, and mean central venous pressure did not change significantly in the postoperative period. The changes documented show the differing pattern of release of water balance hormones invoked by cardiopulmonary bypass. The central role of ANP is shown by its strong correlation with urinary output and its similarly strong relation to fluid balance.


Anaesthetic management of renin secreting nephroblastoma. We report the successful preoperative control and anaesthetic management of severe hypertension in a 7-month-old baby with nephroblastoma and increased renin activity. The strategy for selection of appropriate antihypertensive pharmacological agents and the anaesthetic implications and management of the condition are discussed.


Relationship of the train-of-four ratio to plasma atracurium concentration. The electromyographic response to a short infusion of atracurium 0.25 mg kg-1 was recorded using the train-of-four (TOF) technique, and the plasma atracurium concentration profile measured, in 10 healthy patients. The TOF ratio (T4:T1) was depressed over a time course which did not conform to the predictions of an effect compartment model; the fit of such a model, when possible, was associated with large residual errors. In contrast, the absolute height of the fourth response of the TOF (T4:T0) may be fitted by a standard effect compartment model with smaller errors. This residual error was reduced further on fitting a threshold effect compartment model to the data set T4:T0. The parameter values of such a model were related closely to those for the first response (T1:T0). The kinetics of the effect compartments for the first and fourth response of the TOF were similar, whilst the CPss50 for the fourth response was approximately 67% that for the first response.


Molecular actions of racemic ketamine on human CNS sodium channels. In search of a molecular site and mechanism of action for anaesthetics, we have examined the effects of racemic ketamine on single human CNS sodium channels with the new planar lipid bilayer technique. In the dose range studied (0.05-9.2 mmol litre-1) ketamine depressed in a dose-dependent manner two major functions of the sodium channel, by reducing the fractional open time in a voltage-independent manner (ED50 1.1 mmol litre-1; maximal conductance block 71%) and by interfering with the voltage-dependent, steady-state activation. These actions occurred at concentrations which were greater than those used clinically in general anaesthesia (up to 0.02 mmol litre-1), therefore they reflect local rather than general anaesthetic effects which may be related to the hydrophobic properties of ketamine. In comparison with two other i.v. anaesthetic agents, pentobarbitone and propofol, racemic ketamine behaves differently at both the molecular and the clinical level.


99mTc(V)-DMSA and 99mTc-MDP uptake and no 67Ga-citrate uptake in a case of primary pulmonary leiomyosarcoma. Tumor scintigraphy with 67Ga-citrate, 99mTc(V)-DMSA and 99mTc-MDP were performed on a patient with rare primary pulmonary leiomyosarcoma. While 67Ga-citrate accumulation to the tumor was not recognized, 99mTc(V)-DMSA and 99mTc-MDP scintigraphy showed relatively intense localization of the tracers in the lesion, and were very useful in suggesting the characteristics of the tumor.


Lung cancer.

Lung cancer. In small cell lung cancer, combination chemotherapy including agents such as etoposide, teniposide, cisplatin, doxorubicin, vincristine and cyclophosphamide continues to be the backbone of therapy. Epipodophyllotoxin derivatives, together with cisplatin, are used increasingly as part of the initial therapy. Complete plus partial responses to combination chemotherapy still occur in 80-90% of all patients with a median duration of 9-11 months. Median survival in these studies is at present 11-16 months depending on the initial tumour stage. Deaths from small cell lung cancer continue to occur until 7 years after diagnosis, but rarely thereafter. At this point, overall survival is around 5% and include a small fraction of patients (1%) initially presenting with extensive disease. The optimum duration of treatment is still uncertain. For patients with extensive disease, the use of alternating chemotherapy has been shown in a couple of randomized studies to yield the best results, as judged by long-term survival. The results of several phase II studies stress the importance of dose scheduling of etoposide in small cell lung cancer, with continuous treatment of 5 days' duration or more being superior. The therapeutic results for epidermoid, adenoid, large cell carcinoma and mesothelioma are essentially unchanged. The treatment of patients with these types of lung cancer should continue to be considered experimental, since no standard chemotherapy has as yet been developed, neither when given as single modality nor in combination with surgery or radiotherapy. One single study comparing induction chemotherapy before irradiation vs irradiation alone has resulted in an improvement of median survival of 4 months and doubled the number of long-term survivors. Since three-fourths of the patients with locoregional disease will die within 3 years, further improvements in both systemic and local treatment are needed.


Inhaled budesonide fails to inhibit the PAF-induced increase in plasma leukotriene B4 in man. 1. We studied the ability of inhaled budesonide to modulate PAF-induced acute effects in nine healthy nonsmoking volunteers. Responses in inflammatory cells and mediators in peripheral blood as well as in pulmonary function and circulation were monitored. 2. Inhalation of increasing doses of PAF (total cumulative dose of 500 micrograms) caused a rapid and profound decrease in circulating white blood cells, especially in granulocytes (P less than 0.01), which was turned to an increased number of these cells (P less than 0.05, P less than 0.025, respectively) in the blood samples taken 8 min after completion of the PAF challenge. No changes in the circulating platelets or their thromboxane production were found. Plasma concentrations of histamine or methylhistamine remained unchanged during PAF-inhalation, while plasma LTB4 tripled from the baseline level at 10 min (P less than 0.0005) and was returned to the pre-PAF value at 60 min. 3. PAF inhalation induced a bronchial obstruction (P less than 0.025), but no bronchial hyperresponsiveness to methacholine was found in any of our subjects when measured 24 h after the PAF challenge. Furthermore, PAF caused a decrease in systolic blood pressure (P less than 0.05). 4. Budesonide pretreatment of 400 micrograms twice daily during the preceding 5 days had no effect on any PAF-induced events measured in our study. That fact may also contradict the role of bronchial resident or alveolar cells as a source of the PAF-induced LTB4 burst in plasma. 5. We conclude that in healthy volunteers inhaled PAF induces a marked increase in plasma LTB4, which is not inhibited by inhaled budesonide.(ABSTRACT TRUNCATED AT 250 WORDS)


Drugs acting on calcium channels: potential treatment for ischaemic stroke. Calcium subserves a ubiquitous role in the organisation of cell function. Ca2+ channels which control influx may be modified in disease states. Animal models of cerebral ischaemia do present some problems when investigating potential therapies involving Ca2+ channels. However, it is important not to be too rigid in searching for models which exactly mimic the human disease state, when even the best experimental approaches fall short of such an ideal. There are differences between different classes of calcium entry blocking drugs with regard to their activity on Ca2+ channels and transmembrane Ca2+ movement. Some calcium antagonists may also affect ion channels other than Ca2+, and this potential is exemplified by the novel ion channel modulator RS-87476, which affords experimental neurocytoprotection. Limitation of intracellular Na+ influx during ischaemia-induced depolarization may be useful.


Effects of an angiotensin converting enzyme inhibitor, ramipril, on intracranial circulation in healthy volunteers. off. 1. The effects of a single oral dose (10 mg) of ramipril on (a) systemic haemodynamics (arterial pressure, cardiac output), (b) carotid artery haemodynamics (blood flow and diameter, pulsed Doppler technique), (c) intracranial haemodynamics (middle cerebral artery mean blood velocity, transcranial Doppler technique), and (d) renin-angiotensin system (plasma converting enzyme and renin activities) have been investigated and compared with those of a placebo during the 24 h period following administration in a randomized, double-blind and cross-over study performed in six healthy volunteers. 2. Ramipril induced a strong and sustained inhibition of plasma converting enzyme activity (-96% at 4 h, -63% at 24 h) and an increase in plasma renin activity (+993% at 8 h). 3. As compared with placebo, ramipril did not significantly affect arterial blood pressure, heart rate, cardiac output and total peripheral resistance. 4. Ramipril significantly increased carotid blood flow (by 27% at 8 h) without significantly changing carotid artery diameter, indicating, given the unchanged arterial pressure, an arteriolar vasodilation in the carotid territory. 5. The middle cerebral artery mean blood flow velocity underwent spontaneous modifications during the placebo period but these changes were not affected by ramipril. This lack of influence of ramipril on intracranial haemodynamics suggests that the drug-induced arteriolar vasodilation and increase in carotid blood flow only concern the extracranial, musculo-cutaneous part of the carotid territory.


cAMP control of Mg2+ homeostasis in heart and liver cells. The increase of intracellular cAMP level in intact myocytes and hepatocytes induced by beta-adrenergic stimulation or by forskolin or permeant cyclic AMP analogues induces a sizeable Mg2+ efflux from the cells. Approximately 10-15% of total cell Mg2+ is mobilized over 5-8 min stimulation. The addition of cAMP to digitonin-permeabilized hepatocytes also mobilizes Mg2+ from intracellular compartment(s). Furthermore, cAMP stimulates a major Mg2+ extrusion from isolated rat liver mitochondria, indicating this compartment as the main source of Mg2+ mobilization in liver cells.


Radiolysis of aqueous solutions of guanosine-5'-monophosphate in presence of magnesium ions. A study of the effects of Mg2+ ions on the mononucleotide, guanosine-5'-monophosphate, in the acid form (5-GMPH2) is presented, together with the effects of gamma radiation. The physical methods used to investigate these effects were Fourier Transform Infrared (FT-IR) spectroscopy and mass spectrometry (MS). From the spectral analysis it was found that the nucleotide spectra depend on the presence of Mg2+ ions. The FT-IR intensity changes, together with the mass spectra, suggest the interaction of the magnesium atom with the base guanine at the N7 site, as well as with the phosphate group. This is important, since Mg2+ is usually thought to combine only with the phosphate group. An important finding from the MS spectra was the fact that after irradiation the magnesium atom still seems to be bound to the base at the N7 site.


Genital herpes simplex virus infection: natural history. Genital herpes simplex virus infection is the most common ulcerative sexually transmitted disease diagnosed in North America. Its variability of clinical manifestations, potential for asymptomatic infection and transmission, and recurrent nature make study of genital herpes infections difficult. The biology of herpes viruses, epidemiology and clinical manifestations of genital herpes, modes of transmission, complications, and methods of diagnosis are discussed.


Clinical relevance and evaluation of genitoanal papilloma virus infection in the male. In the light of current epidemiological data, demonstrating a high prevalence of genitoanal papilloma virus infection (GPVI) existing merely in a subclinical or latent form, ambiguity has emanated on the level of ambition that should be considered optimal for the management of GPVI in the male. This review addresses a pragmatic approach to the problem, with an emphasis on diagnosing and treating overt condylomas causing psychosexual disturbance because of the growth of disfiguring but medically rather innocent condylomas, and of flat acetowhite lesions that cause symptoms such as itching, burning, and dyspareunia. The evaluation of children afflicted with genitoanal warts is elucidated. The significance of intraepithelial neoplastic transformation associated with high-risk human papillomavirus (HPV) types such as HPV 16 is discussed, with reference to immunocompetent and immunosuppressed men. Although unequivocal histopathological signs of HPV influence often are absent, conventional light microscopy is usually adequate for differential diagnostic evaluation in clinical routine. In situ hybridization for the detection of HPV DNA may improve histopathologic accuracy.


Understanding human papillomaviral infections in women. Human papillomaviral infections are an increasing concern of clinicians and patients alike. These infections can manifest as overt disease, such as condyloma or genital dysplasias, or can be present at either a subclinical or a latent stage. Because of the correlation between human papilloma virus and lower genital tract cancers, this increased prevalence is of special concern to women and to the clinicians who treat them.


Genital warts--therapy.

Genital warts--therapy. The main goal of the therapy of human papillomavirus (HPV) infection is the management of the virus. There is no cure for HPV infections. The treatment goal for the female patient is to destroy lesions that are malignant or premalignant. The male patient is treated because he is a carrier of HPV who can infect previously uninfected women and possibly reinfect an already treated partner with a potentially oncogenic virus. Various treatment modalities are discussed.


Transformation and degradation of leukotriene B4, 12-hydroxyeicosatetraenoic acid and 5-hydroxyeicosatetraenoic acid induced by ultraviolet radiation. To reveal the underlying mechanisms in the therapeutic effectiveness of ultraviolet (UBV)- and psoralen plus UVA phototherapy, the photostability of leukotriene B4 (LTB4), 12-hydroxyeicosatetraenoic acid (12-HETE) and 5-HETE was investigated in the presence and absence of photosensitizers (8-methoxypsoralen and 5-methoxypsoralen). Arachidonic lipoxygenase products were irradiated with doses of narrow-band UVB (311 nm) ranging from 0.5-3.2 J/cm2, UVB and UVA (305-400 nm) ranging from 0.6-6.3 J/cm2 and UVA ranging from 5.0-60.0 J/cm2, respectively. High-performance liquid chromatography demonstrated a dose-dependent decrease of LTB4, 12-HETE, and 5-HETE. The photostability of 12-HETE was much higher than that of LTB4 and 5-HETE. Two products of transformation of LTB4 were identified as 5(S), 12(R)-dihydroxy-(6E, 8E, 10E, 14Z)-eicosatetraenoic acid [6-trans-LTB4] and 5(S), 12(R)-dihydroxy-(6E, 8Z, 10E, 14Z)-eicosatetraenoic acid [5(S), 12(R)-DiHETE]. There was no significant increase in photodegradation after addition of photosensitizing psoralens.


The skin in severe combined immunodeficiency: a case with transient cutaneous presence of gamma/delta (TRC1+) T cells. We report the case of a boy with severe combined immunodeficiency (SCID) and serious skin problems. The level of purine 5'-nucleotidase was greatly reduced in the lymphocytes of this patient. To our knowledge, no patients with SCID and this enzyme deficiency have been described previously. The relationship between reduced levels of this enzyme and the immunodeficiency is unclear. This case is also unusual because of the presence of large numbers of T lymphocytes expressing TCR1 (gamma/delta) in the skin. Moreover, the presence of so many TCR1-positive cells was not consistent with the low numbers of these cells in the peripheral blood. These cells were not present in skin biopsies taken at a later stage during the course of the disease. An oligoclonal lymphocytosis developed during follow-up, and a monoclonal antibody reactive with these clones was found, indicating that these lymphocytes were present in the skin. This case report illustrates the benefit of the use of monoclonal antibodies in identifying the cells involved in the cutaneous inflammation in SCID, in order to gain a better insight into the characteristics of these cells.


Mechanisms of action of retinoic acid in skin repair. The ability of topically applied retinoic acid to improve photoaged skin has stimulated research interest into its mechanism of action. Currently available assay systems are either in-vitro or mouse models, neither of which are truly representative of the in-vivo situation in man. Another drawback is that skin biopsies available from studies using retinoic acid to treat photoageing are of insufficient size to accomplish biochemical and molecular assays. In order to address these problems, a 4-day in-vivo retinoid assay has been developed which serves as a good predictive model for the chronic effects of retinoic acid on skin and helps to characterize the mechanism of action of retinoic acid.


Retinoic acid and pigment cells: a review of in-vitro and in-vivo studies. Topical tretinoin improves mottling and hyperpigmented lesions of photodamaged skin. The basic mechanisms underlying these effects are not known. It is demonstrated that retinoids inhibit the growth and enhance the differentiation of melanoma cells in vitro, and stimulate the constitutive melanogenesis in melanoma cells in vitro. On the other hand, they inhibit hormonally or pharmacologically induced melanogenesis in these cells. Very few data are available concerning the effect of retinoic acid on normal human melanocytes, but there is some inhibition of growth as in melanoma cells. Retinoic acid appears to have little effect on the melanogenesis of normal human melanocytes grown in vitro using serum-free culture medium. Changes in the shape of these melanocytes suggest that retinoic acid acts on cytoskeleton proteins. Further studies, both in vitro and in vivo, are needed to clarify the effects of retinoic acid on melanocytes.


Analysis of the TNF receptors on human leukaemia cells by affinity cross-linking. Tumour necrosis factor (TNF) affects the growth of human leukaemic cells by different modes of action depending on the type of leukaemia involved. We have analysed the structure of TNF receptors on cells from different types of leukaemia, including acute lymphoblastic leukaemia (ALL), acute myeloblastic leukaemia (AML), chronic lymphocytic leukaemia (CLL), and chronic myelocytic leukaemia (CML) either in chronic phase (CML-CP) or blastic crisis (CML-BC). The affinity crosslinking technique showed the existence of TNF receptors on cells from all the leukaemic cases studied with similar receptor structures. The TNF receptor showed a molecular weight of 76 kD when examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. In conclusion, we provide evidence for existence of TNF receptors on several types of human leukaemia cells with an apparent molecular weight of 76 kD. Apparently, the discrepancy of TNF actions on the leukaemic growth are not related to the structure of TNF receptors.


Characterization and coupling of angiotensin-II receptor subtypes in cultured bovine adrenal fasciculata cells. Angiotensin-II (A-II) receptor subtypes and their potential coupling mechanisms were investigated in bovine adrenal fasciculata cells (BAC) in culture, by the use of selective antagonists for AT1 (DUP 753 or Losartan) and AT2 (PD 123177 and CGP 42112A) sites. Competition for [125I]A-II specific binding with AT1 or AT2 selective ligands produced a biphasic displacement curve, suggesting two distinct A-II binding sites. In the presence of PD 123177 (10(-5) M), a concentration at which most of the AT2 sites were saturated, DUP 753 displaced [125I]A-II specific binding in a monophasic manner with an IC50 of 6.2 +/- 1.4 x 10(-7) M. In the presence of DUP 753 (10(-5) M), the displacement produced by CGP 42112A and PD 123177 was also monophasic, with IC50s of 8 +/- 3 x 10(-10) and 4.6 +/- 2.1 x 10(-7) M, respectively. The reducing agent dithio-1,4-erythritol inhibited the binding of [125I]A-II to AT1 (DUP 753 sensitive) sites, but increased its binding to AT2 sites 2-fold. The IC50 values for these two effects were about 0.5 and 3 mM, respectively. The biological effects of A-II in BAC, phosphoinositide hydrolysis and cortisol production, were inhibited in a dose-dependent manner by DUP 753, but not by AT2 antagonists. Similarly, the potentiating action of A-II on corticotropin-induced cAMP production was blocked by DUP 753, but not by AT2 antagonists. These data indicate that BAC contain both receptor subtypes, but that all the known effects of A-II in BAC were induced via the AT1 receptor subtype.


Ontogenesis of cholesterol side-chain cleavage activity in the ovine adrenal during late gestation. The present study examined the activity of the cholesterol side-chain cleavage system, and the amount of cytochrome P450scc in adrenal glands of sheep fetuses and newborn lambs as well as the in vitro regulation of these parameters. Freshly isolated fetal adrenal cells incubated in the presence of 1 mM 8Br-cAMP or 25 microM 22R-OH cholesterol, produced 4- to 5-fold less pregnenolone than neonatal cells under similar conditions. Likewise, pregnenolone production by isolated fetal adrenal mitochondria was lower than that of neonatal mitochondria when endogenous cholesterol was used as a substrate or when 22R-OH cholesterol was added to the incubation medium. Also, the amount of P450scc, determined by immunoblot, was lower in fetal mitochondria than in neonatal mitochondria. In culture, ACTH, despite enhancing both the production of pregnenolone and the incorporation of [14C]acetate in cholesterol and its end-products by fetal adrenal cells, neither increased the amount of pregnenolone formed from 22R-OH cholesterol nor the amount of immunoreactive P450scc. By contrast, during the first 48 h of culture under standard conditions, there was a "spontaneous" increase in the activity of P450scc which reached values observed in neonatal adrenal cells. Such a development was inhibited when 5% ovine fetal serum was added to the culture medium. These results reinforce the view that in the ovine fetal adrenal gland, the development of P450scc is not ACTH-dependent but involves most probably a decrease in inhibitory factors present in fetal blood.


Further evidence that the mitochondrial proteins induced by hormone stimulation in MA-10 mouse Leydig tumor cells are involved in the acute regulation of steroidogenesis. In previous studies we and others have described several mitochondrial proteins which are synthesized in response to acute hormone stimulation in several steroidogenic tissues. In both MA-10 mouse Leydig tumor cells and primary cultures of rat adrenal cortex cells, these proteins consist of a family of 37 kilodalton (kDa) and 32 kDa precursor forms and fully processed forms which are 30 kDa in molecular weight. The nature of the appearance of these proteins and their subcellular localization to the mitochondria, the site of the rate limiting step in steroidogenesis, has led to the speculation that they may be involved in the acute regulation of steroidogenesis. In the present study we have taken advantage of another steroidogenic cell, the R2C rat Leydig tumor cell, to perform studies which further indicate that these mitochondrial proteins are involved in the regulation of steroidogenesis. Unlike the MA-10 cell which requires hormone stimulation for steroid production, the R2C cell is a constitutive progesterone producer whose steroid production cannot be further increased with hormone stimulation. We have shown that the R2C cell line is less sensitive to the inhibition of steroid production by the metal chelator orthophenanthroline (OP) than is the MA-10 cell. We have demonstrated that progesterone production and the 30 kDa mitochondrial proteins remain present in the R2C cells at a concentration of OP which completely inhibits progesterone production and totally eliminates the 30 kDa proteins in MA-10 cells. As further evidence for the role of these proteins in steroidogenic regulation, we have isolated several revertants of the R2C parent (P) cell line which have lost the ability to synthesize progesterone constitutively, but which can be stimulated to synthesize this steroid by trophic hormone and cAMP analog. In these revertants, designated (R), the normally constitutively present 30 kDa proteins are greatly decreased compared to controls, but reappear in large amounts following hormone stimulation. Taken together, these data provide further evidence that the 30 kDa mitochondrial proteins are involved in the acute regulation of steroidogenesis in Leydig cells.


Interplay of steroid hormone receptors and transcription factors on the mouse mammary tumor virus promoter. The mouse mammary tumor virus (MMTV) promoter, that responds to glucocorticoids and progestins, contains a complex hormone response element (HRE) in the long terminal repeat (LTR) region covered by a phased nucleosome. Hormone treatment leads to alterations in chromatin structure that make the HRE region more accessible to digestion by DNase I and permit binding of transcription factors, including nuclear factor I (NFI), immediately downstream of the HRE. NFI acts as a basal transcription factor on the MMTV promoter in vitro but competes with the hormone receptors in terms of binding to free DNA. In uninduced chromatin, the precise positioning of the DNA double helix on the surface of the histone octamer precludes binding of NFI to its cognate sequence while still allowing recognition of the HRE by the hormone receptors. We postulate that receptor binding to the nucleosomally organized MMTV promoter disrupts the chromatin structure enabling NFI binding and subsequent formation of a stable transcription complex. Whether the receptor remains bound to DNA during induction or is displaced by NFI is not conclusively known, but our evidence supports a "hit and run" mechanism. NFI is not the only factor involved in hormonally induced transcription of the MMTV promoter. Two degenerated octamer motifs located immediately upstream of the TATA box are recognized by the ubiquitous transcription factor OTF-1 (Oct-1, NFIII), and are also important. In vitro, mutations in these motifs do not influence basal transcription, but completely abolish the stimulatory effect of purified progesterone receptor. Progesterone receptor bound to the HRE facilitates binding of OTF-1 to the two octamer motifs. Thus, OTF-1 is a natural mediator of progesterone induction of the MMTV promoter and acts through cooperation with the hormone receptor for binding to DNA.


Unrestrained production of proopiomelanocortin (POMC) and its peptide fragments by pituitary corticotroph adenomas in Cushing's disease. The hallmark of ACTH oversecretion in Cushing's disease is its partial resistance to the normal suppressive effect of glucocorticoids. Because ACTH secretion by the pituitary tumor is not normally restrained ACTH is overproduced with subsequent chronic hypercortisolism. Since peripheral tissues have retained their normal sensitivity to the action of cortisol they appropriately develop the features of Cushing's disease. The question of whether a collection of corticotroph cells, eventually arranged in an adenomatous-like fashion, is a primary pituitary event or is corticotropin-releasing factor driven has had no response so far. Clonal composition of such lesions has been determined by X chromosome inactivation using DNA probes which detect multiallelic polymorphism in females. A monoclonal pattern is found in all macroadenomas. ACTH is co-secreted with other peptide fragments derived from their common polypeptide precursor, proopiomelanocortin (POMC). As a rule POMC processing in pituitary tumors is qualitatively unaltered: plasma values of the N-terminal fragment, the joining peptide, the beta- and gamma-lipotropins, and beta-endorphin all are valid alternate markers of the tumor activity. Tumor POMC peptides including ACTH and its phosphorylated form usually show no peculiar or unexpected molecular forms in contrast with what is often found when POMC expression occurs in a non-pituitary tumor.


Lipoprotein receptors and steroidogenesis in adrenocortical cells. Steroid-producing tissues require a continuous supply of cholesterol for hormone synthesis. In the majority of the steroidogenic tissues the cholesterol is imported via the receptor-mediated uptake of lipoproteins, and therefore the influence on the lipoprotein receptors provides an additional level for the regulation of hormone synthesis. Hormones regulating the adrenocortical activity exert both short- and long-term action, and thus they may control the interactions of the major cholesterol delivery particles--low- (LDLs) and high-density lipoproteins (HDLs)--and their receptors in short- and long-term action, possibly modulating the signal transduction in the former case and the number and distribution in the latter. The LDL and HDL pathway and the signal transduction mechanism is briefly reviewed. Data are discussed concerning short- and long-term action of hormones (alpha-MSH and ACTH, respectively) on the HDL3 receptors of isolated adrenocortical cells. Short-term treatment with alpha-MSH and long-term treatment with ACTH increased the binding of HDL3 to zona glomerulosa and fasciculata cells, respectively, while both treatments increased the hormone production in the presence of HDL. The lipoprotein receptors were frequently found on the microvilli of adrenocortical cell membranes.


Ectopic production of ACTH and corticotropin-releasing hormone (CRH). The most common ectopic production of a pituitary hormone is the one of ACTH leading to Cushing's syndrome. Ectopic ACTH-hypersecretion is the cause of Cushing's syndrome in 10-15% of all cases. The ACTH-secreting tumours are often oat-cell carcinomas of the lung, less frequently pancreatic cancers, hypernephromas, or C-cell carcinomas of the thyroid. Some of these tumours may be benign or semi-benign as the rare carcinoid tumours and cause great problems in the differential diagnosis of ACTH-dependent hypercortisolism. Out of 173 of our patients with Cushing's syndrome observed in the last 12 years 21 were caused by ectopic ACTH-production. Of these 21 patients 13 have a small cell carcinoma of the lung. The ectopic ACTH-syndrome often has typical clinical features caused by the levels of ACTH and cortisol leading to hypocalcemic alkalosis with muscle weakness and wasting, carbohydrate intolerance, and hypertension with oedema. The survival time in many of these patients is not long enough to allow them to develop typical signs of Cushing's syndrome though they are often highly pigmented. These patients are easily diagnosed. However, patients with small tumours which do not cause very elevated ACTH-levels and who have the more typical clinical signs of full-blown Cushing's syndrome are difficult to recognize. For the differential diagnosis of ACTH-dependent Cushing's syndrome the corticotropin-releasing hormone (CRH) stimulation test and dexamethasone suppression test with high doses are helpful. In special cases the venous sampling procedure for ACTH-measurements is necessary, also CT or NMR is helpful. Ectopic CRH-production is a rare cause of ACTH-dependent Cushing's syndrome. Patients with ectopic CRH-production and consecutive ACTH-hypersecretion from the pituitary have not been studied extensively. There are especially no well documented results of the use of the CRH-stimulation test in vivo in this group of patients with Cushing's syndrome. On the other hand, in the documented cases, not only CRH-, but also ACTH-production was found in the tumours. So far, this rare cause of ACTH-dependent Cushing's syndrome has to be excluded or confirmed by the measurement of endogenous CRH-levels. But until now we have not been able to detect one single case of ectopic CRH-production using a sensitive homologous CRH-radioimmunoassay over a period of more than 8 years in which we have seen nearly 120 newly diagnosed patients with ACTH-dependent Cushing's syndrome. Only in the plasma and tumour tissue of two patients of other groups have we found high CRH-levels.


Human Sertoli cells in vitro: morphological features and androgen-binding protein secretion. Sertoli cells play a pivotal role in the regulation of spermatogenesis as they provide the anatomical basis of the blood-testis barrier. In the present paper we report some results of our studies on the ultrastructural features, the responsiveness to FSH, and the ability to secrete androgen-binding protein (ABP) of human Sertoli cells in vitro. The nucleus showed the characteristic foldings of the nuclear membrane, scattered chromatin, and a fibrillar nucleolus. In the cytoplasm Charcot-Boettcher crystals were present and active phagocytic activity was documented by the presence of vacuoles containing lipids and cellular debris. Human Sertoli cells in culture responded to FSH with a maximal rise in cAMP that was approx. 3-fold. This response to FSH is comparable to that reported for the adult rat but lower than that of the immature rat, and suggests that human as well as rat Sertoli cells could have a reduced response to FSH since sexual maturation was achieved. As no evidence has been reported on ABP secretion by human Sertoli cells in culture we evaluated the concentration of this protein in the Sertoli cell spent media. Human Sertoli cells in culture produced ABP and the response to FSH was dose-related. The Kd value of human ABP (hABP) was approx. 7.5 nM, being slightly higher than that of the rat ABP and an order of magnitude different from that of sex hormone-binding globulin (SHBG) present in human plasma. We also measured the association and dissociation rates of dihydrotestosterone-hABP complexes and the Kd/Ka ratio was very close to the value of Kd of the Scatchard analysis. The differences between hABP and SHBG may open the way to the selective measurement of ABP in many conditions of male infertility.


The antitumor activity of radiation therapy is reduced in patients with non-small-cell carcinoma of the lung refractory to chemotherapy. Some in vitro studies demonstrate cross-resistance between chemotherapy (CT) and radiation therapy (RT) but there is no in vivo data showing the same effect. Several studies have estimated the response rate to chemotherapy following radiation, but the question of radiation responsiveness in chemotherapy-refractory tumors has not been examined. Between 1982 and 1988, 162 patients with stage IIIA, IIIB and IV non-small-cell lung cancer (NSCLC) received chemotherapy on various protocols at the National Cancer Center. All were treated until progression or the occurrence of unacceptable toxicity. Forty patients developed local progression on chemotherapy and were given radiation therapy (50 to 60 Gy). Nine responders (22.5%: 95% confidence limit, 9.5-35.5%) were seen in this group, a rate substantially lower than was to be expected with primary radiation treatment. The univariate logistic regression analysis with RT response as the outcome demonstrated that there was significant heterogeneity in response for T and N status between responders and non-responders. Also the odd ratio for radiation dose was strong (OR = 0.20), indicating that a low dose was less likely to produce response although this was not statistically significant. Hematologic toxicity was mild, but 11 patients (27.5%) developed evidence of acute radiation pneumonitis. These results suggest that some chemotherapy-refractory NSCLC may show cross-resistance to radiation therapy which consequently has marginal antitumor activity in this setting.


Management of extragonadal germ-cell tumors and the significance of bilateral testicular biopsies. Forty-nine patients with assumed extragonadal germ-cell tumors (retroperitoneum: 39, mediastinum: 8, CNS: 2) were included in the present study. The patients were treated with 'high' (40 mg cisplatin/m2 and 200 mg etoposide/m2 daily x 5) or 'conventional' (20 mg cisplatin/m2 and 100 mg etoposide/m2 daily x 5) doses of cisplatin and etoposide together with bleomycin, depending on the presence or absence of poor prognosis factors. Forty-six patients were evaluable for response and 3 patients were classified as non-responders (1 early death, 2 toxic deaths). Eighty percent obtained complete remission and 76% are alive without evidence of disease after a median observation time of 41 months (88% of patients with primary tumor in the mediastinum, 72% with tumor in the retroperitoneal area, 87% of patients with seminoma and 71% with non-seminoma, respectively). In 48 patients testicular biopsies were performed. In 42% of patients with primary retroperitoneal tumors, carcinoma in situ testis (CIS) was diagnosed. None of the patients with tumors in mediastinum or CNS had CIS in the testicles. The therapeutic outcome for patients with extragonadal germ-cell tumors is now similar to that of patients with very advanced testicular cancer when considered in relation to the presence of prognostic factors. The coexistence of CIS and retroperitoneal tumor could indicate that these tumors are not truly extragonadal or that these lesions have a common malignant progenitor.


Pneumothorax following induction chemotherapy in patients with lung metastases: a case report and literature review. A 29-year-old patient presented with bilateral pulmonary lesions following surgery for recurrent placental site trophoblastic tumor (PSTT). On day seven after institution of the 'EMA' regimen (etoposide, medium dose methotrexate with folinic acid rescue and actinomycin-D), complete pneumothorax occurred. Closed-system air drainage brought only transient lung expansion and subsequent talc pleurodesis was needed. During follow-up, complete regression of lung metastases was observed. A literature survey of post-chemotherapy pneumothorax in patients with lung metastases disclosed fourteen hitherto reported cases. Including the present PSTT case, non-epithelial gynecologic malignancy (3 patients) ranks second to osteogenic sarcoma (6 cases) with regard to the primary tumor involved.