[The effect of dopamine receptor stimulation on the motor and stereotypic activities of mice with different genotypes]. On mice of 8 highly inbred strains--BALB/c, DBA/2, C57B1/6, CBA, DD, CC57Br, C3H/He, A/He--the role was studied of dopamine receptors of the first and second types (D1 and D2) in the regulation of the general motor activity and stereotypic climbing. Significant dependence was shown of these types of dopamine-dependent behaviour on the genotype. Agonist of D1/D2 receptors, apomorphine decreased the motor activity of animals of the all studied strains, and this effect significantly depended on the genotype. The inhibition of locomotion after selective stimulation of D2 receptors (by LY 171555) was significant. Distribution of mouse strains according to expressiveness of climbing after administration of apomorphine differed from their distribution by the level of motor activity. Selective stimulation of D1 receptors, on the whole, elicited climbing of lesser intensity than D1/D2 activation (excluding CBA strain), and administration of D2 agonist did not induce it at all. Probably, for full expression of behavioural reactions the interaction between D1 and D2 receptors is required.


Genetic analysis of 24 French families with multiple endocrine neoplasia type 2A. The gene for multiple endocrine neoplasia type 2A (MEN2A) has been mapped to the pericentromeric region of chromosome 10 by linkage analysis. Thirty-four families with multiple cases of medullary carcinoma of the thyroid (MTC), including 24 families with origins in France, have been typed with nine polymorphic markers spanning the centromere of chromosome 10. No recombination was observed between the MEN2A locus and either of the four loci D10Z1 (lod score 12.79), D10S102 (lod score 6.38), D10S94 (lod score 7.76), and D10S34 (lod score 5.94). There was no evidence for genetic linkage heterogeneity in the panel of 34 families. Haplotypes were constructed for a total of 11 polymorphisms in the MEN2A region, for mutation-bearing chromosomes in 24 French families and for 100 spouse controls. One haplotype was present in four MEN2A families but was not observed in any control (P less than .01). Two additional families share a core segment of this haplotype near the MEN2A gene. It is likely that these six families have a common affected ancestor. Because the incidence of pheochromocytoma among carriers varies from 0% to 74% within these six families, it is probable that additional factors modify the expression of the MEN2A gene.


Osteogenesis imperfecta type I is commonly due to a COL1A1 null allele of type I collagen. Dermal fibroblasts from most individuals with osteogenesis imperfecta (OI) type I produce about half the normal amount of type I procollagen, as a result of decreased synthesis of one of its constituent chains, pro alpha 1 (I). To test the hypothesis that decreased synthesis of pro alpha (I) chains results from mutations in the COL1A1 gene, we used primer extension with nucleotide-specific chain termination to measure the contribution of individual COL1A1 alleles to the mRNA pool in fibroblasts from affected individuals. A polymorphic MnlI restriction endonuclease site in the 3'-untranslated region of COL1A1 was used to distinguish the transcripts of the two alleles in heterozygous individuals. Twenty-three individuals from 21 unrelated families were studied. In each case there was marked diminution in steady-state mRNA levels from one COL1A1 allele. Loss of an allele through deletion or rearrangement was not the cause of the diminished COL1A1 mRNA levels. Primer extension with nucleotide-specific chain termination allows identification of the mutant COL1A1 allele in cell strains that are heterozygous for an expressed polymorphism. It is applicable to sporadic cases, to small families, and to large families in whom key individuals are uninformative at the polymorphic sites used in linkage analysis, making it a useful adjunct to the biochemical screening of collagenous proteins for OI.


Associations between mutations and a VNTR in the human phenylalanine hydroxylase gene. The HindIII RFLP in the human phenylalanine hydroxylase (PAH) gene is caused by the presence of an AT-rich (70%) minisatellite region. This region contains various multiple of 30-bp tandem repeats and is located 3 kb downstream of the final exon of the gene. PCR-mediated amplification of this region from haplotyped PAH chromosomes indicates that the previously reported 4.0-kb HindIII allele contains three of these repeats, while the 4.4-kb HindIII allele contains 12 of these repeats. The 4.2-kb HindIII fragment can contain six, seven, eight, or nine copies of this repeat. These variations permit more detailed analysis of mutant haplotypes 1, 5, 6, and, possibly, others. Kindred analysis in phenylketonuria families demonstrates Mendelian segregation of these VNTR alleles, as well as associations between these alleles and certain PAH mutations. The R261Q mutation, associated with haplotype 1, is associated almost exclusively with an allele containing eight repeats; the R408W mutation, when occurring on a haplotype 1 background, may also be associated with the eight-repeat VNTR allele. Other PAH mutations associated with haplotype 1, R252W and P281L, do not appear to segregate with specific VNTR alleles. The IVS-10 mutation, when associated with haplotype 6, is associated exclusively with an allele containing seven repeats. The combined use of this VNTR system and the existing RFLP haplotype system will increase the performance of prenatal diagnostic tests based on haplotype analysis. In addition, this VNTR may prove useful in studies concerning the origins and distributions of PAH mutations in different human populations.


Nicotine and the central nervous system: biobehavioral effects of cigarette smoking. The effects of nicotine, like those of other drugs with potential for abuse and dependence, are centrally mediated. The impact of nicotine on the central nervous system is neuroregulatory in nature, affecting biochemical and physiological functions in a manner that reinforces drug-taking behavior. Dose-dependent neurotransmitter and neuroendocrine effects occur as plasma nicotine levels rise when a cigarette is smoked. Circulating levels of norepinephrine and epinephrine increase, and the bioavailability of dopamine is altered as well. Among the neuroendocrine effects are release of arginine vasopressin, beta-endorphin, adrenocorticotropic hormone, and cortisol. Notably, several of these neurochemicals are psychoactive and/or known to modulate behavior. Thus, affective states or cognitive demands may be favorably modified (at least temporarily) by nicotine intake. When nicotine is inhaled, the neuroregulatory effects just described are immediately available and the reinforcing effects of the drug are maximized. On the other hand, nicotine gum and most other nicotine replacement vehicles in current use have a slower onset of action, resulting in less reinforcement value. Recent data suggest that smoking cessation rates may be optimized by tailoring the dose of nicotine replacement (for example, 2 or 5 mg of nicotine gum) to the individual degree of nicotine dependence. In view of the dynamic interactions between the neuroregulatory effects of nicotine and a host of environmental conditions, nicotine replacement therapy is best carried out in combination with behavior modification techniques.


Sinusitis in HIV-1 infection.

Sinusitis in HIV-1 infection. To determine the clinical and radiographic characteristics of sinusitis in patients with human immunodeficiency virus type 1 (HIV-1) infection. A retrospective study was performed that identified all HIV-1-infected patients with sinus radiographs, sinus computed tomograms, or magnetic resonance imaging of the head between 1982 and 1989 (n = 145). Medical record review detailed the clinical course and laboratory parameters in all patients. Eighty-nine patients had radiographic evidence of sinusitis; 75 patients had adequate clinical data and comprise the study group. Acute sinusitis was seen in 10 patients (13%), while all 75 patients had mucosal thickening indicative of chronic sinusitis. Fifty patients (67%) were symptomatic with fever, nasal congestion or discharge, and headache being the most common symptoms; nineteen patients (25%) were asymptomatic when their radiographs showed active disease. The mean CD4 count for the group was 276 cells/mm3; 32 (43%) had CD4 counts less than or equal to 100 cells/mm3. Twenty-three patients (31%) received antibiotics orally, parenterally, or both. Sinusitis appears to occur frequently in HIV-infected patients, is often asymptomatic, may be recurrent or refractory, and may be associated with declining immunocompetence in HIV-infected patients.


The primary structure of the prion protein influences the distribution of abnormal prion protein in the central nervous system. We immunohistochemically examined tissue sections from patients with prion protein (PrP) polymorphism using hydrolytic autoclaving enhancement. Abnormal PrP accumulations could be classified into plaque formations (plaque-type) and the diffuse gray matter stainings including synaptic structures (synaptic-type). Insertional polymorphism, a point mutation in codon 102 or 117/129, and a polymorphism in codon 129 (Val129) result in plaque-type PrP accumulations. The patients with codon 102 mutation also have synaptic-type PrP accumulations. However, a point mutation in codon 200 did not show plaque-type accumulations, and only showed synaptic-type PrP accumulations. Likewise, sporadic Creutzfeldt-Jakob disease patients without any known mutations only have synaptic type accumulations. These results imply that the primary structures of PrP influence the phenotype of prion diseases, especially in abnormal PrP distributions of the central nervous system.


Malignant fibrous histiocytoma. Proliferative compartment and heterogeneity of "histiocytic" cells. To elucidate the precise origin and characteristics of the proliferating cells in malignant fibrous histiocytoma (MFH), the authors analyzed 33 MFH tumors, using immunohistochemical techniques with a panel of 12 antibodies. All three types of MFH cells (spindle cells, polygonal cells, and bizarre giant cells) stained positively for mesenchymal antigens (FU3 and vimentin) but did not stain for macrophage/histiocyte markers (HAM 56 and CD68). Therefore, the MFH cells may not represent true histiocytes, although they may be mesenchymal-derived cells behaving as "facultative histiocytes" with superficial resemblance to actual histiocytes. Normal histiocytes in the stroma tested positive for macrophage/histiocyte antigens; the most common cells were HAM 56-positive cells constituting 30-80% of nonneoplastic stromal cells, followed by those positive for CD68 (10-50%), Mac 387 (less than 2%), and S-100 protein (less than 1%). Our results indicate the presence of heterogeneity of "histiocytic" cells in MFH. Proliferating-cell nuclear antigen (PCNA) was expressed not only in the spindle and polygonal MFH cells but also in the bizarre giant cells. These findings suggest that all three types of MFH cells participate in the proliferative compartment of MFH. Uneven PCNA staining of the irregular nuclear segments of the bizarre giant cells may result in abnormal DNA synthesis, possibly contributing to the marked diversity of nuclear morphology in MFH. Touton-type and osteoclast-like giant cells did not stain for PCNA but stained positively for histiocytic markers. Therefore, these giant cells may lack proliferative activity and probably result from normal histiocytes fusing together.


Bacteriophage phi 105clz induces the GroEL-homologue protein in Bacillus subtilis. Using two-dimensional polyacrylamide gel electrophoresis, the GroEL homologue of Bacillus subtilis was shown to be induced upon infection with phi 105clz, a clear plaque mutant of the temperate bacteriophage phi 105. Western blotting of one dimensional polyacrylamide gels also showed the induction of the GroEL homologue when cells were infected with phi 105clz.


Clinical and laboratory correlates of human immunodeficiency virus infection in a cohort of intravenous drug users from New York, NY. The human immunodeficiency virus (HIV) epidemic has increasingly involved intravenous drug users. Few studies have attempted to define its clinical and laboratory characteristics in this population. We recruited 223 intravenous drug users from New York, NY, for a prospective study of the natural course of HIV infection. Medical history, physical examination, medical staging, and immunologic assessments were performed at 6-month intervals. We examined the baseline findings among this cohort. Of the total cohort, 65.9% were men and 34.1% were women, with 70.9% African American, 12.6% white, 11.7% white Latino, and 4.9% black Latino. At baseline, 44.4% were HIV negative and 55.6% were HIV positive. No significant association was noted between ethnicity, gender, and serologic status. Also no significant difference was noted for homelessness either across serologic status or gender. There was a trend toward an association between gender and use of drugs during the week before interview; the women showed higher drug use. A significant association was noted between HIV serologic status and reported history of pneumonia, oral candidiasis, cough, night sweats, fever, and lymphadenopathy on physical examination. In a regression model, white blood cell count, hematocrit, symptom/sign complex score, and CD4 cell number were significantly associated with HIV status. This study provided important historical, clinical, and immunologic characteristics that are useful in the identification and evaluation of the HIV-infected intravenous drug user.


Receptor systems in the non-failing human heart. Catecholamines acting through beta 1- and beta 2-adrenoceptors cause positive inotropic and chronotropic effects in the human heart. In recent years, however, evidence has accumulated that in the human heart also other receptor systems can affect heart rate and/or contractility. Positive inotropic effects can be mediated by receptor systems acting through accumulation of intracellular cAMP (Gs-protein coupled receptors such as 5-HT4-like, histamine H2, and vasoactive intestinal peptide) or by receptor systems acting independent of cAMP possibly through the phospholipase C/diacylglycerol/inositol-1,4,5-trisphosphate pathway (such as alpha 1-adrenergic, angiotensin II, and endothelin). In the non-failing human heart, however, activation of all these receptor systems induces only submaximal positive inotropic effects when compared with those caused by beta-adrenoceptor stimulation, indicating that in humans the cardiac beta-adrenoceptor-Gs-protein-adenylate cyclase pathway is the most powerful mechanism to increase heart rate and contractility. On the other hand, at least three receptor systems acting through inhibition of cAMP formation (Gi-protein coupled receptors) exist in the human heart: muscarinic M2-, adenosine A1-, and somatostatin-receptors. Activation of M2- and A1-receptors causes negative inotropic effects in the non-failing human heart: in atria activation of both receptors causes decreases in basal as well as in isoprenaline-stimulated force of contraction, but in ventricles only isoprenaline-stimulated force of contraction is depressed.


Sequence of the complete cDNA and the 5' structure of the human sucrase-isomaltase gene. Possible homology with a yeast glucoamylase. The complete sequence of the 6 kb cDNA and the 5' genomic structure are reported for the gene coding for the human intestinal brush border hydrolase sucrase-isomaltase. The human sucrase-isomaltase cDNA shows a high level of identity (83%) with that of the rabbit enzyme, indicating that the protein shares the same structural domains in both species. In addition to the previously reported homology with lysosomal alpha-glucosidase, the sucrase and isomaltase subunits also appear to be homologous to a yeast glucoamylase. A 14 kb human genomic clone has been isolated which includes the first three exons and the first two introns of the gene, as well as 9.5 kb 5' to the major start site of transcription. The first exon comprises 62 bp of untranslated sequence and the second starts exactly at the initiation ATG codon. Typical CAAT and TATA boxes are seen upstream of the first exon. A genetic polymorphism is described which involves a PstI site in the second intron. Southern blotting, sequencing and mRNA studies indicate that the structures of the sucrase-isomaltase gene and its mRNA are unaltered in the two human colon cancer cell lines Caco-2 and HT-29 in comparison with normal human small intestine.


Interaction of P-glycoprotein with a hydrophobic component of rat urine. The presence of an endogenous P-glycoprotein substrate in rat urine was examined by testing the ability of a hydrophobic extract to reverse multidrug resistance in CHO cells and to inhibit [3H]azidopine photolabelling. The accumulation of several hydrophobic drugs and dyes, known to be transported by P-glycoprotein, was dramatically enhanced in multidrug-resistant CHO cells (CHRC5) by a component contained in a hydrophobic extract prepared from rat urine by octadecyl (C18) reverse phase chromatography. The biological action of this urinary component involves a direct interaction with P-glycoprotein since it blocked photolabelling of the protein with [3H]azidopine. The effective concentration of the substance required to enhance drug accumulation and inhibit photolabelling was similar and within the range of its urinary content. These results suggest that a hydrophobic substance in urine may be an endogenous substrate of kidney P-glycoprotein.


Alterations in expression and structure of the DNA repair gene XRCC1. The repair-associated gene XRCC1 was previously cloned by complementing the hamster mutant EM9, which has a high rate of spontaneous SCE and hypersensitivity to DNA damaging agents. In analyzing XRCC1 gene expression, similar levels of steady-state mRNA were found in normal cells, Bloom's syndrome cells with altered SCE, and in squamous carcinoma cells with differential X-ray sensitivity. An EcoRI restriction fragment-length polymorphism previously identified in XRCC1 did not correlate with the repair phenotypes of these cells. The mRNA of XRCC1 decreased to 20-40% after treatment of cells with a DNA damaging agent. XRCC1 also showed tissue specific expression in rats. The mRNA levels were high in testis (7-8 fold), ovary (3-4 fold) and brain (4-5 fold), when compared with those in intestine, liver and spleen (1-2 fold). These data and the high levels of XRCC1 protein detected in testis indicate that XRCC1 may play an important role in DNA processing during meiogenesis and recombination in germ cells.


Total prevention of the development of in vitro tolerance to organic nitrates. Experiments with antioxidants. The nearly total inhibition of development of pharmacological tolerance to an organic nitrate is reported here for the first time. The development of in vitro tolerance in the rabbit aorta to isosorbide-5-mononitrate (CAS 87-33-2) was potently inhibited by five structurally unrelated antioxidants--diaminodurol, ascorbic acid, potassium sulphite, pyrogallol and quercetin. Diaminodurol, ascorbic acid and potassium sulphite decreased, but quercetin increased, the spasmolytic activity of isosorbide-5-mononitrate. Diaminodurol, potassium sulphite, quercetin and ascorbic acid potently inhibited the spasmolytic activity of nitric oxide (NO). Quercetin also inhibited the development of in vitro tolerance to glyceryl trinitrate. It is suggested that tolerance to organic nitrates is the result of biochemical damage caused by a reactive intermediate such as NO. To test this possibility directly the effect of pretreatment with NO on the spasmolytic activity of glyceryl trinitrate (CAS 55-63-0) was examined. This pretreatment produced a small but significant tolerance to glyceryl trinitrate and to SIN-1 (3-morpholinosydnone imine), which also acts through guanylate cyclase. There was no effect on the activity of the unrelated vasodilators nitrendipine and theophylline. It is concluded that the reaction between NO and soluble quanylate cyclase is a real but minor cause of tolerance to organic nitrates. Other possible mechanisms of tolerance development are discussed.


Inhibition of human phospholipase C by aurothiomalate and (triethylphosphine) gold complexes. The effect of several gold complexes on the activity of phospholipase C from human blood platelets was studied in vitro. Aurothiomalate and auranofin--2 agents used for the chrysotherapy of rheumatoid arthritis--, gold chloride, (triethylphosphine)gold chloride, and 5 newly synthesized (triethylphosphine)gold complexes dose-dependently inhibited the enzyme with IC50 values between 0.8 mumol/l ((triethylphosphine)gold chloride) and over 100 mumol/l (auranofin). None of the compounds affected phospholipase A2 from human polymorphonuclear leukocytes at concentrations up to 100 mumol/l. Inhibition of phospholipase C by (triethylphosphine)gold chloride, aurothiomalate, and compound 3 was not significantly different at substrate concentrations of 20 and 100 mumol/l phosphatidylinositol, suggesting that these gold complexes do not inhibit phospholipase C by competing with the substrate. After confirming the Ca2+ dependence of the human platelet phospholipase C by demonstrating inhibition by the Ca2+ chelators EDTA and EGTA--but no inhibition by the Zn2+ chelator 1,10-phenanthroline--the inhibition of the enzyme by (triethylphosphine)gold chloride, aurothiomalate, and compound 3 was studied at 3 different concentrations of Ca2+ in the range of 0.2 to 2 mmol/l. Inhibition by (triethylphosphine)gold chloride was not affected by changes of Ca2+, whereas inhibition by aurothiomalate and compound 3 was markedly suppressed by increasing the Ca2+ concentration.(ABSTRACT TRUNCATED AT 250 WORDS)


Expression of c-erb B-2/neu proto-oncogene in human prostatic cancer tissues and cell lines. Both amplification and overexpression of c-erb B-2/neu have been associated with the progression and possible prognosis of a number of human cancers. In this study, we demonstrated that c-erb B-2/neu may also play an important role in human prostate cancer. Our conclusion is based on the following observations: (1) A monoclonal antibody raised against a peptide sequence from the C-terminal domain of the human c-erb B-2/neu gene product reacted positively with 68.7% (11 of 16) of the human prostatic cancer tissue extracts analyzed by western blot procedure. These results were supported by the immunohistochemical staining of the prostatic cancer specimens; 80% (12 of 15) showed positive staining, primarily around the plasma membranes of the prostatic cancer cells. c-erb B-2/neu oncoprotein was not detectable in normal prostate tissues (five examined by immunohistochemical staining and three by western blotting) or in human benign prostatic hyperplasia (two examined by immunohistochemical staining and six by western blotting) and was expressed less abundantly with lower intensity in "normal" human prostate tissues adjacent to cancerous prostate tissue (5 of 12 examined by immunohistochemical staining). We observed no evidence of c-erb B-2/neu gene amplification in 10 fresh human prostatic cancer specimens examined by Southern blotting and in the cultured human prostatic cancer cell lines PC-3, DU-145, and LNCaP. (2) The c-erb B-2/neu protein was detected in both androgen-receptor-positive (LNCaP) and -negative (PC-3 and DU-145) human prostate cancer cell lines. Positive immunostaining of c-erb B-2/neu protein was found to be associated predominantly with the plasma membranes of PC-3 cells, but was also found to be widespread in the cytoplasmic region of the LNCaP cells and in the perinuclear region of the DU-145 cells. (3) Like prostate-specific antigen (PSA) expression, c-erb B-2/neu mRNA expression was also positively regulated by androgen in androgen-receptor-positive LNCaP cells in vitro and LNCaP tumors in vivo. When LNCaP tumors were grown in castrated male hosts, levels of c-erb B-2/neu and PSA mRNA expression decreased initially, but rebounded at 3 wk to levels comparable to those expressed by tumors maintained in intact adult male hosts.


Dyskinesia and neuroleptic exposure in elderly psychiatric inpatients. A wide variation in prevalence rates of tardive dyskinesia and spontaneous orofacial dyskinesia has been reported in the elderly. To clarify these discrepancies, we studied 45 patients over the age of 60 years admitted to a short-term psychiatric unit. Standardized criteria for the diagnosis of dyskinesia were used. We found a rate of tardive dyskinesia of only 21% (7/33) in our patients having a history of neuroleptic exposure. We found no cases (0/12) of spontaneous orofacial dyskinesia. There was a significant association between tardive dyskinesia and psychiatric diagnosis, with the highest rate of tardive dyskinesia in those patients with schizophrenic disorders, followed by those with organic disorders and mood disorders, respectively. There was also a significant association between the presence of tardive dyskinesia and radiographic evidence of cortical atrophy, and a trend towards an association with leukoencephalopathy. Our results suggest that published rates of tardive and spontaneous dyskinesia in the elderly may overestimate the prevalence of these disorders, especially among geriatric patients with acute psychiatric presentations.


Glutathione S-transferase in chemotherapy resistance and in carcinogenesis. Cytosolic glutathione S-transferases are composed of two monomeric subunits. These monomers are the products of different gene families designated alpha, mu, and pi. Dimerization yields either homodimeric or heterodimeric holoenzymes within the same family. The members of this complex group of proteins have been linked to the detoxification of environmental chemicals and carcinogens, and have been shown to be overexpressed in normal and tumor cells following exposure to cytotoxic drugs. They also are overexpressed in carcinogen-induced rat liver preneoplastic nodules in rat liver. In all of these cases, the changes in expression of glutathione S-transferases are paralleled by increased resistance to cytotoxic chemicals. The degree of resistance is related to the substrate specificity of the isozyme. The relationship of the glutathione S-transferase genes to drug resistance has been directly demonstrated by gene transfer studies, where cDNAs encoding the various subunits of glutathione S-transferase have been transfected into a variety of cell types. This review discusses the results of numerous studies that associate resistance to alkylating agents with overexpression of protective detoxifying glutathione S-transferase enzymes.


Multifactorial resistance to antineoplastic agents in drug-resistant P388 murine leukemia, Chinese hamster ovary, and human HeLa cells, with emphasis on the role of DNA topoisomerase II. The role of DNA topoisomerase II in multifactorial resistance to antineoplastic agents is reviewed. We have previously observed that in Adriamycin (ADR) resistant P388 murine leukemia cells, DNA topoisomerase II enzyme content and cleavage and catalytic activities were all reduced and correlated with drug sensitivity. A subsequent study provided evidence for an allelic mutation of the gene for DNA topoisomerase II as a possible molecular mechanism underlying the enzyme alterations. To ascertain how universal were these observations, a study was undertaken of DNA topoisomerase II (topo II) in other cell lines resistant either to ADR or another topo-II-interactive drug, mitoxantrone. In ADR-resistant Chinese hamster ovary (CHO) cells, topo II cleavage and catalytic activities and the gene product were all reduced; however, only cleavage activity correlated with drug sensitivity. No differences were noted between ADR-sensitive and -resistant CHO cells by Northern or Southern blot analysis, raising the possibility that the enzyme in resistant cells may be regulated at a posttranscriptional level. Findings on a gel retardation or immunoblot band depletion assay showed that the enzyme in CHO/ADR-1 cells failed to bind to the DNA-drug-enzyme complex, suggesting a qualitative as well as quantitative enzyme alteration in those cells. Mitoxantrone-resistant HeLa cells (Mito-1) displayed not only a lower level of cleavage activity but also of enzyme content and catalytic activity, relative to the parental drug-sensitive HeLa cells. As with the CHO cells, no differences were noted between mitoxantrone-sensitive and -resistant HeLa cells on Northern and Southern blot analyses, suggesting that enzyme regulation in these resistant cells may also be at a posttranscriptional level. There was no evidence of enzyme binding to DNA-drug-enzyme complex in resistant HeLa/Mito-1 cells, once again suggesting the presence of a qualitative enzyme alteration. The findings in both ADR-resistant CHO cells and mitoxantrone-resistant HeLa cells do not exclude the possibility that subtle changes in the topoisomerase II gene, such as point mutations, may account for these enzyme changes. The apparent qualitative changes observed in enzyme may result from posttranslational modifications such as phosphorylation.


L-histidinol in experimental cancer chemotherapy: improving the selectivity and efficacy of anticancer drugs, eliminating metastatic disease and reversing the multidrug-resistant phenotype. Human cancer chemotherapy is limited by two major problems: the failure of commonly used anticancer drugs to act against tumor cells in a specific manner and the ability of malignant cells to resist killing by antineoplastic agents. Experimentally, both of these problems can be solved by using L-histidinol in combination with conventional anticancer drugs. A structural analogue of the essential amino acid L-histidine and an inhibitor of protein biosynthesis. L-histidinol improves the selectivity and the efficacy of a variety of cancer drugs in several transplantable murine tumors. Furthermore, L-histidinol circumvents the drug-resistant traits of a variety of cancer cells, including those showing multidrug resistance. This review will summarize these properties of L-histidinol, present new evidence on its ability to increase the vulnerability of both drug-sensitive and drug-resistant human leukemia cells to various anticancer drugs, and show that, in addition to inhibiting protein synthesis, L-histidinol acts as an intracellular histamine antagonist. The establishment of a connection between the latter mechanism and the capacity to modulate anticancer drug action has resulted in a clinical trial in the treatment of human cancer.


Microtubule distribution during fertilization in the rabbit. The distribution of microtubules was studied during fertilization of the rabbit oocyte by immunofluorescence microscopy after staining with an anti-alpha-tubulin antibody. In ovulated oocytes, microtubules were found exclusively in the meiotic spindle. At fertilization, the paternal centrosome generated sperm astral microtubules. During pronuclear development, the sperm aster increased in size, and microtubules extended from the male pronucleus to the egg center and towards the female pronucleus. These observations indicate that microtubules emanating from the sperm centrosome were involved in the movements leading to the union of the male and female pronuclei. At late pronuclear stage, microtubules surrounded the adjacent pronuclei. The mitotic spindle that emerged from the perinuclear microtubules contained broad anastral poles.


Multiple sites of Hox-7 expression during mouse embryogenesis: comparison with retinoic acid receptor mRNA localization. We report results from a study of Hox-7 expression during mouse embryonic and fetal development and compare the localization of Hox-7 transcripts with those of the retinoic acid receptors. Transcripts were detected by in situ hybridization. Hox-7 expression occurs in (1) cephalic neural crest and its derivatives, (2) sites of ectomesodermal interaction, (3) extraembryonic tissues, and (4) endocardial cells. Hox-7 does not seem to be involved in defining rostrocaudal boundaries, but instead appears to be expressed along the proximodistal axes at these sites. We further investigated the active sites of morphogenesis, which involve an ectomesodermal interaction (e.g., limb buds, visceral arches), including genital tubercle and tail ridge. These are regions highly positive for Hox-7 transcripts, and many are known to be sites for the expression of gamma-retinoic acid receptors (RARs) and cellular retinoic acid binding proteins. Most regions that express Hox-7 are subregions of gamma-RAR expression. In the developing limb bud, expression of Hox-7 takes place in the interdigital region, where it overlaps areas of beta-RAR expression.


c-fos proto-oncogene expression in bronchial biopsies of asthmatics. c-fos, a proto-oncogene regulating the transcription of many genes, plays a critical role in the cell cycle and differentiation and may be involved in the regulation of inflammation in asthma. Very low levels of c-fos are detectable in most human cells, and its expression is rapidly and transiently increased by multiple factors, some of which are involved in the airways inflammation of asthma (histamine, eicosanoids, and cytokines). The presence of c-fos protein, as detected by immunofluorescence, and the immunoreactivity of PCNA, a cell proliferation marker, were examined in bronchial biopsies obtained from 12 asthmatics and 10 normal subjects. Biopsies of eight of 12 asthmatics expressed c-fos versus none of 10 normal subjects. The expression was heterogeneous and localized to cells positive for anti-cytokeratin monoclonal antibody, indicating their epithelial origin. On the other hand, PCNA immunoreactivity was only observed in one asthmatic and one control subject but it was not related with c-fos expression. This study demonstrates the induction of c-fos in epithelial cells of asthmatics, suggesting a role for this proto-oncogene in activation rather than in proliferation.


The role of CD18-mediated adhesion in neutrophil sequestration induced by infusion of activated plasma in rabbits. Infusion of activated plasma induces neutropenia and sequestration of neutrophils within the microvasculature. This study examined the role of the adhesion glycoprotein complex, CD11/CD18, in this sequestration. Rabbits pretreated with either the anti-CD18 monoclonal antibody (mAb) 60.3 or saline were given infusions of zymosan-activated plasma (ZAP) or saline. The effect of mAb 60.3 on the changes in circulating neutrophil counts, radiolabeled neutrophil kinetics in the lung, and the pulmonary microvascular accumulation of neutrophils induced by ZAP infusion was determined. The data show that pretreatment with mAb 60.3 did not inhibit either the rate of onset or the severity of the neutropenia but prevented the sustained neutropenia. In addition, mAb 60.3 completely prevented the ZAP-induced changes in radiolabeled neutrophil kinetics and largely inhibited the accumulation of neutrophils within the capillaries and the small vessels when evaluated after 15 min of ZAP infusion. We conclude that neutrophil accumulation is a two-step process, the first occurring through a CD18-independent mechanism that may involve a stimulus-induced decrease in neutrophil deformability and acts to slow neutrophil transit through the lung. The second step requires CD18-dependent adhesion and is needed for prolonged accumulation of neutrophils within the pulmonary microvasculature.


Expression and function of beta 2 integrins on alveolar macrophages from human and nonhuman primates. The alveolar macrophage (AM) participates in diverse, adherence-related activities required for host defense and the inflammatory response. The beta 2 integrins (the CD11/CD18 heterodimer) mediate some of these activities on circulating leukocytes and peritoneal macrophages. We investigated expression of the CD11/CD18 leukocyte integrin subunits on AMs obtained by bronchoalveolar lavage of human and nonhuman primates. We also determined the role of the CD11/CD18 complex in AM chemotaxis and adherence to A549 alveolar epithelial cell monolayers. Immunofluorescence flow cytometry indicated that the CD11a/CD18 complex was expressed in high levels and CD11b/CD18 and CD11c/CD18 in lower levels on the AM surface. Northern blot analysis indicated the presence of CD11a, CD11c, and CD18 mRNA in the AMs. Smaller quantities of CD11b mRNA were also found. AM chemotaxis to zymosan-activated serum was markedly inhibited by a monoclonal antibody to CD18. In addition, adherence of AMs to A549 cells (stimulated by tumor necrosis factor to upregulate intercellular adhesion molecule-1 expression) was decreased from 30.3 +/- 5.0 to 20.8 +/- 2.4% (P less than 0.05) by the same monoclonal antibody. We conclude that: (1) AMs obtained from human and nonhuman primates constitutively express predominantly CD11a/CD18 surface antigen and mRNA, (2) chemotaxis of AMs is CD18 dependent, and (3) adhesion of AMs to an alveolar epithelial cell monolayer is partly but not completely dependent on the beta 2 integrins.


Induction of ICAM-1 expression on human airway epithelial cells by inflammatory cytokines: effects on neutrophil-epithelial cell adhesion. Inflammation of the human airways in diseases such as chronic bronchitis, cystic fibrosis with Pseudomonas endobronchial infection, and possibly asthma during late-phase reactions involves a local influx of neutrophils (PMN) that may participate in airway epithelial injury. PMN-mediated cellular injury is most efficient under conditions of PMN-target cell adhesion. PMN express adhesive glycoproteins of the CD11/CD18 family that are counter-receptors for intercellular adhesion molecule-1 (ICAM-1), found on various cell types. We proposed that adherence by PMN to human airway epithelial cells via ICAM-1 might be an important mechanism in inflammatory airway diseases. We found that although PMN adhere poorly (less than 5%) to monolayers of human tracheal epithelial cells (TEC) in primary culture, they adhere readily (45 to 50%) to an SV40-immortalized line of human TEC, designated 9HTEo-. We also found 6-fold greater surface expression of ICAM-1 on 9HTEo- compared with primary TEC. Blocking surface ICAM-1 on 9HTEo- cells with specific monoclonal antibody inhibited PMN adherence by about 50%. Thus, ICAM-1 plays a major role in this adherence, although it is possible that other epithelial ligands contribute also. Antibodies to CD11a, CD11b, and CD18 on PMN also inhibited PMN-epithelial adherence. Treatment of primary TEC monolayers with the proinflammatory cytokines interleukin-1 (IL-1) or tumor necrosis factor-alpha (TNF-alpha) caused a 3- to 4-fold increase in both cell surface ICAM-1 expression and support of PMN adhesion.(ABSTRACT TRUNCATED AT 250 WORDS)


Coronary "open" endarterectomy and reconstruction: short- and long-term results of the revascularization with saphenous vein versus IMA-graft. From June 1984 to December 1990, 96 patients underwent "open" coronary endarterectomy and reconstruction. In 50 patients (group 1), a saphenous vein (SV) graft was used to reconstruct and bypass 54 coronary vessels. In 46 patients (group 2), 46 coronary vessels were reconstructed with an SV patch and then bypassed with the internal mammary artery (IMA): Seventy-four LAD coronary arteries (36 in group 1 and 38 in group 2) were treated with these procedures. Operative mortality was 8% in group 1 and 2.1% in group 2. Five patients (10%) in group 1 and 1 patient (2.1%) in group 2 developed perioperative myocardial infarction. The early postoperative patency of the reconstructed vessels was 84.6% in group 1 and 92.5% in group 2. Angiographic controls were performed between 30 and 36 months after operation in 18 patients (72%) of group 1 and in 16 patients (69%) of group 2 with patency rates of 66.7% and 81.5%, respectively. A further angiographic study performed between 54 and 60 months after operation of 9/22 patients of group 1 and 5/9 patients of group 2 did not show any additional closure of the endarterectomized vessels. Three- and 5-year survival analyzed by the Kaplan-Meier method was 79.6% and 69.7%, respectively, in group 1 and 86.8% for both the 3- and 5-year survival in group 2. After a mean follow-up of 51.0 and 35.5 months, 62.8% of the surviving patients of group 1 and 75.6% of group 2 were asymptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)


Internal mammary artery bypass graft for impaired coronary perfusion after neonatal arterial switch operation. Myocardial ischaemia caused by perfusion impairment of translocated coronary arteries is the major cause of perioperative mortality after neonatal arterial switch operation for transposition of the great arteries. We report the successful use of the right internal mammary artery as a bypass graft to a dominant right coronary artery to treat insufficient perfusion of this artery in a newborn. Eight months later, coronary angiography showed a full blood supply of the right coronary artery across the internal mammary anastomosis. After a follow-up period of more than 30 months, somatic development, electrocardiogram and echocardiographically determined contractility of both ventricles are practically normal indicating regular function of the bypass graft.


An immunohistochemical study on the pancreatic endocrine cells of the three-toed sloth, Bradypus variegatus. The cellular composition and relative frequency of the occurrence of pancreatic endocrine cells were studied immunohistochemically in a primitive eutherian and arboreal folivore, the three-toed sloth, since previous histochemical and ultrastructural studies on the endocrine pancreas of the sloth have detected only a single islet cell type, the A cell. In the sloth pancreas, four types of endocrine cells immunoreactive for glucagon, insulin, somatostatin and serotonin (5-hydroxytryptamine) were found as reported in the pancreas of human and common experimental mammals, but pancreatic polypeptide-immunoreactive cells were not detected by either avian- or bovine-pancreatic polypeptide antiserum. The endocrine cells were distributed mainly in the islets and partly also in the exocrine tissue including the pancreatic ducts. Larger or smaller clusters consisting of glucagon- and insulin-immunoreactive cells were also found frequently in the interlobular connective tissue. In the islets, glucagon- and insulin-immunoreactive cells were the most prominent cell type, while somatostatin- and serotonin-immunoreactive cells were sparse. The most striking feature in the sloth pancreas is the high frequency of glucagon-immunoreactive cells, because these cells are by far less in number than insulin-immunoreactive cells in the islets of human and common experimental mammals. This appears to be an intriguing characteristic of the sloth pancreas in a possible relation to the animal's unique metabolic system and the phylogenetical position.


Expression and modification of Hox 2.1 protein in mouse embryos. A polyclonal antibody, alpha Hox 2.1a, has been generated and used to immunolocalize Hox 2.1 protein in mouse embryos. Protein is present in nuclei of all tissues previously shown to express Hox 2.1 RNA. In addition, protein is seen in somites and proximal regions of the limb buds, tissues in which Hox 2.1 RNA expression was not clearly detected previously by in situ hybridization. At the 7 somite stage, protein is detectable in the neural tube up to the level of somite 1, but later retracts to a more posterior position. Immunoblot, in vitro translation, and immunoprecipitation experiments were carried out to characterize the Hox 2.1 protein. The results show that the Hox 2.1 gene produces at least two related phosphorylated proteins present in different proportions in different tissues.


Clinical characteristics of haemorrhagic fever with renal syndrome in children. From January 1988 to September 1989, seven patients (4 girls and 3 boys, aged 3-12 years) with haemorrhagic fever with renal syndrome (HFRS) were hospitalised at the University Children's Hospital in Belgrade. In four patients the disease appeared as a family outbreak, the others were sporadic cases. In six patients the clinical presentation was suggestive of HFRS, as they had fever with headache, myalgia, sore throat and gastrointestinal illness followed by renal abnormalities. However, severe haemorrhagic syndrome with petechia, haematoma, haematemesis and melaena was present in one patient only. Renal disease presented as nephritic syndrome and/or acute renal failure. Five patients recovered after 2-3 weeks without sequellae, one patient had decreased renal function 17 months after the start of the disease and the remaining patient died. In six patients the diagnosis of HFRS was confirmed serologically by a significant rise in antibody titres against hantaviruses, while in the patient with the fetal and fulminant course of the disease, the diagnosis was established on the basis of epidemiological and autopsy findings. We suggest that children living in endemic areas who develop an ill-defined, febrile and gastrointestinal disease with renal dysfunction should be evaluated for HFRS.


Hox-3.6: isolation and characterization of a new murine homeobox gene located in the 5' region of the Hox-3 cluster. Most members of the murine Hox gene system can be grouped into two subclasses based on their structural similarity to either one of the Drosophila homeotic genes Antennapedia (Antp) or Abdominal B (AbdB). All the AbdB-like genes reported thus far are located in the 5' region of their respective cluster. We describe here the isolation, structural characterization and spatio-temporal expression pattern of a new AbdB-like homeobox gene designated Hox-3.6 that is located in the 5' region of the Hox-3 cluster. Hox-3.6 has an extreme posterior expression domain in embryos of 12.5 days of gestation, a feature that has thus far only been observed for the 5' most genes of the Hox-4 cluster. Like the other members of the AbdB subfamily, Hox-3.6 exhibits spatially restricted expression in the hindlimb bud, but the expression domain is antero-proximal in contrast to the postero-distal domain reported for its cognate gene Hox-4.5. Structural analysis of the 5' region revealed the presence of a 35 bp sequence which shares homology and relative 5' position with an upstream sequence present in its two nearest downstream neighbors, Hox-3.2 and -3.1.


Maturation of CD4-8- alpha/beta TCR+ T cells induced by CD2-stimulation in vivo and in vitro. Newly generated ('virgin') rat thymocytes of the immature CD4+8+ double positive (DP) subset were treated in suspension culture for 2 days with the stimulatory pair of anti-CD2 monoclonal antibodies OX-54 and OX-55. Approximately 50% of the recovered cells had downregulated CD4 and CD8 and upregulated the T cell antigen receptor (TCR). CD2-stimulated, but not control thymocytes proliferated in response to TCR plus IL-2 stimulation. In vivo, postnatal injection of OX-54/55 led to a dramatic and selective increase in functionally mature CD4-CD8- double negative (DN) alpha/beta--TCR(high) thymocytes and peripheral T cells. These findings show that CD2 stimulation can promote T cell differentiation and suggest that DN TCR(high) thymocytes can be generated from DP thymocytes via alternative pathways of T cell maturation.


Interleukin-2 induces tumor necrosis factor-alpha production by activated human T cells via a cyclosporin-sensitive pathway. We examined requirements for TNF-alpha production by purified human blood T cells, completely depleted of monocyte-accessory cells, under different conditions of stimulation. Activation of T cells with immobilized anti-CD3 induced the appearance of mRNA for TNF-alpha and of functionally active TNF-alpha in the culture supernatant. Anti-CD3-induced TNF-alpha production could be inhibited by blocking the IL-2R with a combination of anti-Tac and Mik beta 1 (mAbs against the p55 and p75 chain of the IL-2R respectively) thus indicating an essential role of IL-2 in TNF-alpha induction. When purified T cells were activated with a combination of two anti-CD2 mAbs (9-1 and 9.6), additional signals (rIL-2 or rIL-1 beta or anti-CD28) were required for TNF-alpha mRNA production and protein secretion. rIL-1 beta supported anti-CD2-induced TNF-alpha production indirectly through an IL-2-dependent pathway. These same helper signals also enhanced TNF-alpha production by anti-CD3-stimulated T cells. IL-4, IL-6, GM-CSF and IFN-gamma had no effect on TNF-alpha production by T cells activated via either pathway. Addition of rIL-1 beta alone, rIL-2 alone or endotoxins to resting human T cells did not induce detectable amounts of TNF-alpha. Both helper/inducer CD4(+) and suppressor/cytotoxic CD8(+) subsets of T cells were shown to produce TNF-alpha upon stimulation. We conclude that CD3 or CD2 triggering are not sufficient for TNF-alpha production by T cells, but that the latter is dependent (apparently at the transcriptional level) on the interaction of IL-2 with its functionally active cell surface receptors. We could further demonstrate that TNF-alpha production was completely blocked by cyclosporin A. The inhibitory effect of this agent on TNF-alpha production was also observed in the presence of rIL-2, thus excluding an indirect effect through inhibition of IL-2 production.


Effect of dexmedetomidine, an alpha 2-adrenergic agonist, in the isolated heart. Dexmedetomidine (DM) was studied in the isolated dog heart in the form of a Starling heart-lung preparation, (HLP). Hearts were subjected to increased loading by (a) increasing cardiac output, and (b) increasing systemic resistance. Results are depicted by cardiac function curves, prepared by plotting left atrial pressure against either systemic cardiac output or mean arterial pressure. DM, given in divided doses up to 44 micrograms, had no effect on heart rate or cardiac function, nor did injection of 0.5 mg of atipamezole, a selective alpha 2-antagonist. Additional injections of very large doses of DM, up to 4,444 micrograms, caused an increase in heart rate and a leftward shift of the function curves, ie, positive chronotropic and inotropic effects. Plasma catecholamine levels increased markedly between the 444 micrograms and the 4,444 micrograms cumulative doses of DM. Administration of 1 mg of prazosin had no effect, but 1 mg of propranolol returned the rate to baseline and markedly shifted function curves to the right and depressed their slopes. Thus, whereas low doses (corresponding to between 1 and 30 micrograms/kg in intact animals) of DM, given acutely IV, have been shown to depress cardiac function in intact and denervated dogs, this effect is not due to a direct effect on the myocardium. High doses, far beyond doses maximally effective in intact animals and man, release catecholamines from cardiac stores. Plasma DM levels after low doses in the HLP were between 1 to 10 times those seen in intact animals and human volunteers after the usual doses given clinically for their central effects. Because DM caused no myocardial depressant effect in the isolated, blood-perfused canine HLP, decreases in cardiac function seen after this drug is given to intact and autonomically denervated dogs must be due to factor(s) other than a direct action on the myocardium.


Florence: cytokines and T-cell subsets.

Florence: cytokines and T-cell subsets. The second international congress on cytokines, held in Florence (March 23-25, 1992), has been marked by the presentation of recent data about cytokine-deficient mice obtained by homologous recombination which, contrary to expectation, exhibit normal T and B cell development. The cloning of a few new cytokines and receptors were also reported as well as recent advances in the knowledge of the oldest members of this quickly growing family. The meeting has also been marked by a great number of reports providing insights into T cell-dependent immune response. Participants provided evidence, through their different experimental models, that functional T helper dichotomy, TH1 versus TH2, was of physiological relevance both in mice and humans, while other reports highlighted the differential regulation of these T lymphocytes subsets. An interesting discussion took place about their differentiation process and the harmonization of the concepts of naive, memory and effector T cells with the T subset classification according to cytokine production profile.


Identification of a point mutation in factor XIII A subunit deficiency. Oligonucleotide primers have been designed for the amplification of all 15 exons of the human coagulation factor XIII A subunit gene. Each exon and its intron flanking regions has been amplified and sequenced from a patient with severe A subunit deficiency. A single G to A transition in the last base of exon 14 has been identified in the homozygous proband and in his heterozygous parents. The mutation would result in the substitution 681 Arg to His in the mature protein product. However, because the mutation is at a splice junction, the deficiency may result from a defect in pre-messenger RNA splicing.


The skin as a target organ for the investigation of antiallergic drugs: comparison between cetirizine and terfenadine. Two double-blind clinical pharmacology studies were performed in atopics in order to compare the inhibitory effects of cetirizine (CTZ) 2 HCl and terfenadine (TER) on histamine and antigen-induced skin reactions. In the first study, the subjects took single intakes of CTZ 10 mg and TER 60 mg. In the second study, they took CTZ 10 mg once a day and TER 60 mg b.i.d. for 3 weeks. CTZ was more effective than TER in inhibiting histamine skin reactivity. CTZ and TER were equally effective in inhibiting antigen-induced reactions. There was no tachyphylaxis, either for CTZ or for TER.


Kimura's disease with marked proliferation of HLA-DR+CD4+ T cells in the skin, lymph node and peripheral blood. A 41-year-old female had atopic dermatitis-like skin lesions since the age of 21, and for the past 6 years many skin tumors developed on the body, lower extremities and other areas. The histological picture of the tumor, eosinophilia and high IgE in the peripheral blood were consistent with a diagnosis of Kimura's disease. Although the tumors were markedly reduced by oral prednisolone administration, thereafter papules appeared disseminated over the body with swelling of superficial lymph nodes. Immunohistochemical examination indicated marked proliferation of HLA-DR+CD4+ T cells in the skin and lymph nodes, and two-color flow cytometry confirmed it in the lymph nodes and peripheral blood.


Drugs for treatment of peptic ulcers.

Drugs for treatment of peptic ulcers. Pharmacologic management of peptic ulcer disease continues to evolve with the introduction of diverse types of new therapeutic agents. The ideal aims of treatment of peptic ulcer disease are to relieve pain, heal the ulcer, and delay ulcer recurrence. This article provides a broad perspective on the pharmacology and therapeutic actions of antiulcer drugs. To date, no drug meets all goals of therapy. Drug treatment of peptic ulcers is targeted at either counteracting aggressive factors or stimulating the mucosal defense. Drugs that inhibit or neutralize gastric acid secretion include histamine H2-receptor antagonists, proton pump inhibitors, anticholinergics, prostaglandins, and antacids. H2-receptor antagonists have become first-line drugs for treatment of uncomplicated duodenal ulcers, gastric ulcers, prevention of ulcer relapse, and mild esophagitis. However, H2-receptor antagonists, like other gastric antisecretory/antiulcer drugs, have high rates of ulcer recurrence following discontinuation of therapy. They therefore need to be administered continuously in patients prone to such recurrences. Omeprazole has emerged as a major drug for the treatment of severe erosive esophagitis, refractory ulcers, and Zollinger-Ellison syndrome. The major disadvantage of proton pump inhibitors is the concern for their long-term safety. The roles of M1-antimuscarinic agents and antacids have not been fully defined. Misoprostol, effective for the treatment of gastric and duodenal ulcers, is now the only drug that prevents ulcers induced by nonsteroidal anti-inflammatory drugs. Mucosal protective drugs that do not inhibit gastric acid secretion include sucralfate and organic bismuth salts. Sucralfate is a nonsystemic, well-tolerated, effective drug for treatment of duodenal ulcers and prevention of duodenal ulcer relapse. The organic bismuth salt bismuth subcitrate is efficacious in the treatment of duodenal and gastric ulcers. Furthermore, it has also been established that it alters the course of ulcer recurrence. However, bismuth encephalopathy is a major toxicity concern that needs to be addressed.(ABSTRACT TRUNCATED AT 250 WORDS)


Distinguishing neuroleptic malignant syndrome (NMS) from NMS-like acute medical illnesses: a study of 34 cases. A study of 34 hospitalized patients with suspected neuroleptic malignant syndrome (NMS) found that 24 had NMS and the other 10 had acute, usually serious, medical problems. There were no demographic, psychopathologic, or treatment-related differences between the groups. NMS patients had more dehydration, cogwheeling, diaphoresis, disorientation, drooling, dysphagia, and rigidity and higher diastolic blood pressure. The groups had similar fevers, heart rates, creatine kinase levels, and white blood cell counts. Three non-NMS patients died during their acute illnesses. Results suggest that considering NMS as a diagnosis and ruling out other acute illnesses such as pneumonia are equally important when a patient on neuroleptic medication becomes medically ill.


Effects of ionizing radiation on a plant genome: analysis of two Arabidopsis transparent testa mutations. Ionizing radiation is known to cause chromosomal alterations such as inversions and deletions and has been used extensively for inducing mutations. In Arabidopsis, two methods for the isolation of genes identified on the basis of mutant phenotypes--genomic subtraction and chromosome walking--either rely on or are greatly facilitated by the availability of these types of mutations. This article gives a detailed characterization of ionizing radiation-induced mutations in plants. The Arabidopsis genes encoding chalcone flavanone isomerase (CHI) and dihydroflavonol 4-reductase (DFR) were cloned and found to correspond to two transparent testa loci. A CHI allele, generated by fast-neutron irradiation, consisted of an inversion within the gene. A 272-bp fragment from 38 centimorgans away on the same chromosome was transferred to one end of this inversion. A DFR allele, induced by x-irradiation, contained two deletions and an inversion of the 2.8-centimorgan intervening region. Sequence analysis of the break points in both mutants indicate that repair of radiation-induced damage involves mechanisms similar or identical to those that mediate the integration of foreign sequences into the genome. The chromosome rearrangements found in these mutants have important implications for the use of ionizing radiation-induced alleles in classical and molecular genetic experiments in plants.


Role of NMDA receptors in hypothalamic facilitation of feline defensive rage elicited from the midbrain periaqueductal gray. The present study tested the hypothesis that the pathway from the medial hypothalamus to the midbrain periaqueductal gray (PAG) subserving defensive rage behavior in the cat facilitates the occurrence of this response when elicited from the PAG by utilizing excitatory amino acids as a neurotransmitter or neuromodulator. Cannula electrodes were implanted into the PAG for the elicitation of defensive rage behavior as well as for microinjections of excitatory amino acid antagonists and N-methyl-D-aspartic acid (NMDA). Monopolar stimulating electrodes were also implanted into the medial hypothalamus from which this response could also be elicited and, when stimulated at subthreshold levels for elicitation of behavior, could also facilitate the occurrence of PAG elicited defensive rage. Initially, dual stimulation of the PAG and medial hypothalamus facilitated the occurrence of defensive rage elicited from the PAG. Then, the identical dual stimulation paradigm was repeated with the same current parameters following the infusion of various antagonists for different receptors into the PAG defensive rage sites. The results indicate that infusion of either kynurenic acid [(0.1-2.0 nmol), a non-selective excitatory amino acid receptor antagonist] or D-2-amino-7-phosphonoheptanoic acid (AP7) [(0.1-2.0 nmol), a specific NMDA receptor antagonist], produced a dose and time dependent blockade of the facilitatory effects of medial hypothalamic stimulation. In contrast, microinjections of relatively larger doses of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) [(4 nmol), a non-NMDA receptor (quisqualate and kainate) antagonist] or atropine [(4.4 nmol), a muscarinic receptor antagonist] had little effect upon medial hypothalamically elicited facilitation of the PAG response. In a second experiment, NMDA [0.1-1.0 nmol] was microinjected directly into PAG defensive rage sites in the absence of medial hypothalamic stimulation. In these animals, drug infusion mimicked the effects of dual stimulation by producing a dose and time dependent decrease in response latencies. A third experiment was designed to further test the hypothesis by neuroanatomical methods. Here, the retrograde label, Fluoro-Gold, was microinjected into defensive rage sites within the PAG and following a survival time of 5-6 days, the animals were sacrificed. The brains were then processed for immunocytochemical analysis of cells that immunoreact positively for aspartate and glutamate. The results indicated the presence of many retrogradely labelled and immunocytochemically positive cells within the rostro-caudal extent of the medial hypothalamus as well as others that were double labelled.(ABSTRACT TRUNCATED AT 400 WORDS)


Lateral hypothalamic area neurotransmission and neuromodulation of the specific cardiac effects of insular cortex stimulation. Microstimulation of the rat posterior insular cortex in phase with the ECG R wave elicits pure cardiac effects unaccompanied by changes in blood pressure or respiration. This technique has successfully demonstrated cardiac chronotropic organisation and arrhythmogenesis within the insula. Pathways exist linking the insular cortex with the lateral hypothalamic area (LHA). Similarly, the LHA has previously been shown to mediate the sympathetic and blood pressure effects of insular cortex stimulation. Therefore it was anticipated that the tachycardia elicited by insular phasic microstimulation would be responsive to LHA manipulations. Insular tachycardia sites in 28 chloralose-anesthetised male Wistar rats were phasically stimulated once with each cardiac cycle using 500 microA for 1 min before and after microinfusions (390 nl) into the LHA. The insular tachycardia response was abolished by LHA microinfusions of the synaptic blocker cobaltous chloride (4 mM). LHA microinjection of kynurenic acid (250 mM) attenuated insular tachycardia by 95%. Microinjection of naloxone (30 mM) similarly attenuated the tachycardia by 95%. Met-enkephalin (3.5 mM) was without effect on this response whereas Leu-enkephalin (3.5 mM) and neuropeptide Y (0.01 mM) (NPY) doubled the magnitude of the tachycardia. Dynorphin (0.12 mM), a specific kappa opioid receptor agonist, augmented the response to stimulation of insular tachycardia sites 8-fold. Consequently, it is suggested that the LHA contains an obligatory synapse mediating insular tachycardia and that glutamate is the likely neurotransmitter at this site. Neuromodulation of insular tachycardia may be effected by opiate kappa and NPY receptors, a finding of considerable clinical relevance.


Somatotopic organization of tyrosine hydroxylase expression in the rat locus coeruleus: long term effect of RU24722. Tyrosine hydroxylase (TH) tissue concentration was determined by immunostaining of tissue sections directly transferred onto nitrocellulose membranes in the restricted region of the noradrenergic perikarya of the locus coeruleus (LC) along its postero-anterior axis. TH containing cells were systematically counted on adjacent post fixed sections stained by immunohistochemistry. The absolute quantity of TH was estimated in each section and was found to be linearly related to the number of TH immuno-positive cells found in the adjacent section. The ratio between these two parameters was thus used as an index of the cellular concentration of TH in noradrenergic cells. In the LC of control rats, the TH cellular concentration was lower (-39%) in the anterior than in the posterior half of the structure. Three days after an injection of 20 mg/kg of RU24722, an eburnamine derivative known to increase the quantity of TH in the LC, increases in quantities of TH were found in both portions of the LC. Moreover in the posterior LC the increase in the amount of TH resulted from a significant increase in the number of TH-immunopositive cells. In the anterior part, however, it was primarily the result of a significant increase in TH cellular concentration. Throughout the LC there was an increase in the cellular concentration of TH which was inversely proportional to the concentrations found in control animals. TH mRNA content was measured by a quantitative in situ hybridization in sections of both the posterior and anterior LC one day after a single injection of RU24722 at the same dose. The quantity of TH mRNA was significantly increased in both parts. The number of TH mRNA-expressing neurons also increased, especially in the anterior LC. Thus the effects at the level of TH protein and TH mRNA were strikingly parallel though increase in TH protein occurred later than the increase in the TH mRNA. These results suggest that in the rat LC: (1) there is a significant population of 'sleeping cells' in which TH expression is either inactivated or, at a low level of activation; (2) TH cellular concentration could exert a retrocontrol on its own expression in cells of the LC that contained TH and (3) TH expression appears to be regulated by different selective mechanisms in these two different subpopulations of noradrenergic cells within the LC.


Glutamate-immunoreactive synapses on retrogradely-labelled sympathetic preganglionic neurons in rat thoracic spinal cord. Retrograde tracing with cholera toxin B subunit (CTB) combined with post-embedding immunogold labelling was used to demonstrate the presence of glutamate-immunoreactive synapses on sympathetic preganglionic neurons that project to the adrenal medulla or to the superior cervical ganglion in rat thoracic spinal cord. At the electron microscope level, glutamate-immunoreactive synapses were found on retrogradely labelled nerve cell bodies and on dendrites of all sizes. Two-thirds of the vesicle-containing axon profiles that were directly apposed to, or synapsed on, CTB-immunoreactive sympathoadrenal neurons were glutamate positive. The proportion of glutamate-immunoreactive contacts and synapses on sympathoadrenal neurons decreased to zero when the anti-glutamate antiserum was absorbed with increasing concentrations of glutamate from 0.1 mM to 10 mM. Double immunogold labelling for glutamate and gamma-aminobutyric acid (GABA) showed that glutamate-immunoreactive profiles did not contain GABA and that GABA-immunoreactive profiles did not contain glutamate. These results suggest that glutamate is the major excitatory neurotransmitter to sympathoadrenal neurons and possibly to other sympathetic preganglionic neurons in the intermediolateral cell column of the spinal cord.


Glutamate antagonists applied to midbody spinal cord segments reduce the excitability of the fictive rostral scratch reflex in the turtle. Glutamate antagonists applied to the cutaneous-processing region of the rostral scratch circuit in turtles reduced the excitability of the rostral scratch reflex. Segments D3-D6 (D3 = 3rd postcervical) of the midbody spinal cord receive cutaneous afferents from the rostral scratch receptive field and perform the initial integration of this cutaneous sensory input. These cutaneous-processing segments are located anterior to the rostral scratch motor pattern generator that resides mainly in segments D7-D10 located in and near the hindlimb enlargement. We prepared 1 or 2 of the midbody segments for bath application of glutamate antagonists in preparations with a complete transection of the spinal cord anterior to segment D3. Each preparation was immobilized by neuromuscular blockade and fictive scratch motor output was recorded from hindlimb muscle nerves. Application of the NMDA N-methyl-D-aspartate) antagonist APV (D-2-amino-5-phosphonovaleric acid, 50 microM) to a midbody segment significantly reduced the motor burst frequency of rostral scratch responses evoked by 3-Hz electrical stimulation of a site in that segment's dermatome. These data suggest that NMDA receptors contribute to cutaneous processing in the rostral scratch circuit. Application of APV to a midbody segment also reduced the magnitude of temporal summation in the scratch circuit in response to electrical stimuli delivered to the shell at 4- to 5-s intervals. Temporal summation was monitored at the level of hindlimb motor output as well as at the level of unit activity from 'long-afterdischarge' neurons in the midbody segments. Our observations are consistent with the hypothesis that NMDA receptors contribute to the prolonged activation of 'long-afterdischarge' neurons and the multisecond storage of excitation in the scratch reflex pathway.


Kappa opiate receptors mediate tail-shock induced antinociception at spinal levels. Previous work has demonstrated that 3 pharmacologically and neuroanatomically distinct analgesia systems can be sequentially activated by increasing numbers of transcutaneous tail-shock. To date, the categorization of the early (after 2 tail-shocks) and late (after 80-100 tail-shocks) analgesias as opiate-mediated has been based on the ability of systemic naltrexone and morphine tolerance to block these effects. In contrast, the analgesia observed after 5-40 tail-shocks is unaffected by these manipulations, leading to its categorization as non-opiate. The present work and the following companion paper were aimed at identifying the neuroanatomical loci at which endogenous opiates exert their analgesic effects in this tail-shock paradigm and, further, to identify which opiate receptor subtypes are involved. The 3 experiments included in the present paper focus on the role of spinal opiates in tail-shock induced analgesia. The first experiment demonstrates that the tail-shock parameters used do not directly activate pain suppressive circuitry within the spinal cord, but rather activate centrifugal pain modulation circuitry originating within the brain. The last two experiments examine the effect of intrathecal microinjection of either naltrexone (a relatively non-selective opiate receptor antagonist), binaltorphimine (kappa receptor antagonist), Cys2-Tyr3-Orn5-Pen7-amide (CTOP) (mu receptor antagonist), or naltrindole (delta receptor antagonist). Taken together, these latter 2 experiments demonstrate that both the early (after 2 shocks) and late (after 80-100 shocks) opiate analgesias are mediated by kappa opiate receptors within the spinal cord.


Effects of microtubule stabilization and destabilization on tau immunoreactivity in cultured hippocampal neurons. Tau immunoreactivity is altered in neurofibrillary tangles (NFT) and degenerating neurites in Alzheimer's disease (AD). In addition, cytoskeletal proteins including tau are excessively phosphorylated in AD. Previous data indicated that calcium influx can cause antigenic changes in tau in cultured rat hippocampal and human cortical neurons similar to those seen in NFT. The present study used cultured hippocampal neurons to test the hypothesis that disruption of microtubules is a key event leading to altered antigenic properties of tau that result from calcium influx. As previously reported, we found that glutamate (100-500 microM) and calcium ionophore A23187 (0.5-1 microM) elevated intraneuronal calcium levels and caused a reduction in microtubules, a marked increase in staining with Alz-50 and 5E2, and a decrease in tau-1 immunoreactivity. The microtubule-disrupting agent colchicine (1 microM) caused increased immunoreactivity of neurons towards tau antibodies Alz-50 and 5E2, and these effects of colchicine occurred in the absence of an increase in intracellular calcium levels. The microtubule-stabilizing drug taxol (100 nM) reduced neuronal immunoreactivity towards Alz-50 and 5E2 in untreated cultures and in cultures exposed to glutamate or A23187. Western blot analysis indicated that A23187 caused a reduction in tau levels which was partially prevented by taxol, suggesting that tau associated with microtubules is less susceptible to calcium-mediated degradation. Acid phosphatase treatment increased neuronal immunoreactivity towards tau-1 and reduced immunoreactivity towards Alz-50. The calcium-induced alterations in tau immunoreactivity were, and the colchicine-induced alterations were not, affected by acid phosphatase treatment. Taken together, the data indicate that microtubule depolymerization can cause antigenic changes in tau similar to those seen in NFT independently of an increase in intraneuronal calcium levels. Stabilization of microtubules prevented the antigenic changes in tau suggesting that microtubules affect the availability and/or properties of epitopes on tau that are recognized by antibodies that stain NFT.


Age-related changes in cortico-releasing factor, somatostatin, neuropeptide Y, methionine enkephalin and beta-endorphin in specific rat brain areas. We investigated the age-related changes in the tissular protein, cortico-releasing factor (CRF), somatostatin (SOM), neuropeptide Y(NPY), methionine enkephalin (M-ENK) and beta-endorphin (beta-END) levels in frontal cortex, hippocampus, striatum and hypothalamus of young (4-month-old), mature (18-month-old) and senescent (26-month-old) Wistar male rats, bred in a specific pathogen free environment. Between the age of 4 and 18 months, the tissular protein levels increased in all 4 structures studied. The CRF and SOM levels increased in the hippocampus, while the NPY levels decreased. During this time, the NPY content increased in the striatum, whereas the SOM and M-Enk striatal levels decreased. Concomitantly, the NPY and beta-End levels decreased in the hypothalamus. Interestingly, no significant variations were found to occur in the frontal cortex whatever the neuropeptide studied. Between the age of 18 and 26 months, no significant changes in the tissular protein levels were detected, except in the hippocampus. The changes in the neuropeptide concentrations observed during this period depended on the neuropeptide and the brain structure studied. The CRF and beta-End levels decreased in the frontal cortex and the hypothalamus, respectively. The NPY peptidergic systems seem to be preferentially affected by aging processes since 3 out of the 4 structures studied--the frontal cortex, the striatum and the hypothalamus--showed a decrease in their tissular NPY content. During the same period, none of the 5 neuropeptides studied were affected in the hippocampus.


Interaction between aminergic systems in mesolimbic structures: the importance of 5-HT2, D2 and D1 receptors in the olfactory tubercle for the atypical profile of neuroleptics. This study shows that the 5-HT2 antagonists ketanserin and ritanserin which on top of administration of classical neuroleptics reduces negative symptoms in schizophrenia as well as extrapyramidal side effects, are the most potent inhibitors of the dopamine-specific responses of the olfactory tubercle (OT); like atypical neuroleptics (2), they are far less effective when injected in the nucleus accumbens (ACC). We suggest that 5-HT2, D2 and/or D1 antagonism within the olfactory tubercle is necessary, but not sufficient for the atypical profile of neuroleptics.


Conditioned release of neurotransmitters as measured by microdialysis. The purpose of this research was to measure conditioned release of neurotransmitters in vivo and to study their role as neuromodulators in neural circuits controlling food intake. 1. Extracellular serotonin (5HT) was measured in the hypothalamus during (a) injection of the anorectic drug d-fenfluramine, (b) a normal meal and (c) during the taste of a flavor that previously had been paired with nausea. All these situations increased 5HT, suggesting it plays a role in suppression of food intake. 2. Extracellular dopamine (DA) in the nucleus accumbens (NAC) was released (a) during eating and (b) by a conditioned taste associated with intragastric infusion of carbohydrate, but (c) DA decreased in response to a taste that had been paired with nausea. Thus some DA projections to the NAC may modulate circuits that reinforce eating safe food. Drugs that release DA mimic, in part, this safe food effect.(ABSTRACT TRUNCATED AT 250 WORDS)


Selective inhibition of normal murine myelopoiesis "in vitro" by a Hox 2.3 antisense oligodeoxynucleotide. Multiple homeobox genes are expressed in haematopoietic cell lineages and their expression is cell-type specific. Thus we hypothesized that certain homeobox genes may play an important role in the process of haematopoiesis. To prove that issue, normal murine bone marrow cells were stimulated with appropriate Colony Stimulating Factors in the presence of mouse homeobox gene (Hox 2.3) sense or antisense oligodeoxynucleotides and the effects on the haematopoietic colony formation were examined. Treatment of the cells to Hox 2.3 antisense oligodeoxynucleotides led to a selective inhibition of myeloid colony formation, both in size and in numbers, but without significant effect on erythroid and megakaryocytic haematopoiesis. Exposure to Hox 2.3 sense oligodeoxynucleotides (no-oligomers), had no such effect. It was further showed that inhibition of myelopoiesis by Hox 2.3 antisense oligodeoxynucleotides was dependent on the differentiation stage of target cells. These findings demonstrated that Hox 2.3 gene plays a critical role in regulating normal murine myelopoiesis.


Effects of ionophore X-537A on spontaneous transmitter release and the ultrastructure of locust neuromuscular junctions. The spontaneous quantal release of neurotransmitter and the fine structure of a glutamatergic synapse has been examined in the presence of ionophore X-537A. Bath applications of X-537A to extensor tibiae nerve-muscle preparations of locust, Schistocerca gregaria, increased the frequency of miniature excitatory post-synaptic potentials (min. e.p.s.p.'s). This action was completely reversible, if preparations were exposed to ionophore for less than 60 min. Application of ionophore for longer times, i.e., longer than 60 min., transiently elevated min. e.p.s.p. frequency to greater than 100/s. Following this period of high activity, miniature frequency declined to 0.4/s and were mostly of "giant" miniature potentials type. The frequency and amplitude of these "giant" miniature potentials remained unchanged after subsequent washing with standard saline. Exposure of nerve terminals to ionophore for 60 min. produced no ultrastructure changes. Longer ionophore treatments, however, led to depletion of synaptic vesicles, damaged mitochondria and disintegration of microtubules and neurofilaments within nerve terminals, suggesting irreversible changes at the locust neuromuscular junction.


Cytoskeletal changes accompanying ACTH-induced steroidogenesis in cultured embryonic adrenal gland cells from the Pekin duck. Cells derived from the adrenal glands of duck embryos immediately prior to hatching were grown in culture and used to study the morphological and cytoskeletal changes and steroidogenic responses induced by 1-24 ACTH. Changes in the cytoskeletal components were observed by rhodamine-phalloidin staining for actin and by staining the tubulin immunoreactive components with FITC. The cultures were comprised of a small population of chromaffin cells and a larger population of steroidogenic cells. The chromaffin cells were distinguished by their tyrosine hydroxylase immunoreactivity. The steroidogenic cells were characterized by the presence of sudanophilic lipid droplets, numerous mitochondria, abundant smooth endoplasmic reticulum, microtubules distributed as a fairly even network throughout the cytoplasm, and microfilaments that formed an extensive and elaborate system of stress fibers with many parallel arrays. The cells readily responded to stimulation with ACTH by releasing corticosterone, aldosterone and deoxycorticosterone. Stimulation with ACTH also induced changes in both the cell morphology and the cytoskeleton. Exposure of the cells to Krebs-Henseleit buffer containing 1-24 ACTH caused them to form numerous fine filopodia, to lose their stress fibers, and to form a thick ring of actin at the periphery of the cell. In addition, many cells became extremely arborized with many long branched dendritic processes. The morphological changes appeared to be related to a redistribution of the actin components, and may be explained only in part by the rounding up or retraction of the cytoplasm. The results strongly suggest an involvement of the actin components of the cytoskeleton in the steroidogenic response to corticotropic stimulation.


Symptomatic angina secondary to coronary-subclavian steal syndrome treated successfully by percutaneous transluminal angioplasty of the subclavian artery. Subclavian artery stenosis causing severely symptomatic angina in a patient with a previous left internal mammary artery bypass to the left anterior descending artery was treated successfully with percutaneous transluminal angioplasty. Baseline arteriography clearly revealed subclavian and coronary steal by evidence of competitive flow of nonopacified blood from the left vertebral artery. Although there was a difference of only 15 mm Hg between the right and left brachial arteries, there was a palpable difference in the upstroke of these pulses. The stenosis in the subclavian artery was successfully dilated with percutaneous transluminal angioplasty. Angiographic evidence of subclavian steal resolved following balloon dilatation, and the patient's angina was completely resolved.


The alpha 2-adrenergic receptor system in the hypothalamus of the Pekin duck. In the present study, we have employed the monoradioiodinated alpha 2-agonist clonidine ([125I]-CLO) to characterize duck hypothalamic alpha 2-adrenoceptors and to localize alpha 2-specific binding sites in the duck brain. To validate the alpha 2-specificity of [125I]-CLO using an enriched duck hypothalamic membrane fraction, a radioreceptor assay was established by altering the membrane protein concentration, time, temperature and ionic milieu of incubation, and in the presence or absence of protease inhibitors. Competitive displacement studies revealed the following sequence of potency to displace [125I]-CLO: yohimbine greater than (-)-epinephrine greater than clonidine greater than (-)-norepinephrine greater than phentolamine greater than (-)-phenylephrine greater than (-)-isoproterenol greater than prazosin. The non-hydrolyzable guanosine 5'-triphosphate analog guanylylimidodiphosphate markedly inhibited [125I]-CLO binding suggestive of G-protein involvement. With regard to the histological distribution, diencephalic structures, such as the habenula and the nucleus reticularis of the thalamus, were densely labeled by [125I]-CLO. In the hypothalamus, alpha 2-adrenoceptors were detected in the antidiuretic hormone-synthesizing nucleus paraventricularis, the nucleus praeopticus medialis, the nucleus anterior medialis hypothalami, the nucleus magnocellularis praeopticus, the nucleus commissurae pallii, the nucleus inferior hypothalami and the regio lateralis hypothalami. Circumventricular organs, such as the plexus choroidei, organum subfornicale, organum paraventriculare and the corpus pineale, were endowed with alpha 2-specific binding sites, as were the cell layers of the tectum opticum. In addition, telencephalic structures revealed high receptor densities.(ABSTRACT TRUNCATED AT 250 WORDS)


Chloroform inhibits the development of diethylnitrosamine-initiated, phenobarbital-promoted gamma-glutamyltranspeptidase and placental form glutathione S-transferase-positive foci in rat liver. In this study we demonstrate that chloroform, a widely used industrial solvent, a medicinal chemical and a common drinking water contaminant, reduces the number of detectable preneoplastic enzyme-altered foci [gamma-glutamyltranspeptidase-positive (GGT+) and placental form glutathione S-transferase-positive (GST-P+)] in the liver of male Fischer 344 rats. The animals were given a partial hepatectomy and 18 h later received a single oral dose of either 0.5 mmol/kg diethylnitrosamine (DENA) or saline. Two weeks later, groups of 12 animals were started on drinking water containing phenobarbital with varying concentrations (200-1800 mg/l) of chloroform fro 12 weeks. Treated and control animals were killed and the number and the volume of GGT+ and GST-P+ expressing hepatic foci were tabulated. The numbers of foci per unit volume (and per unit area), the percent focal volume and the focal liver were reduced by chloroform in a dose-dependent manner. The mean focal volume was not influenced by chloroform. A plausible explanation for these results could be that chloroform exerts its focal inhibitory effect either by selectively killing the putative initiated cells, by retarding the inherent growth rate of enzyme-altered cells or by reducing the effectiveness of the promoter, phenobarbital. The available evidence suggests that the first hypothesis is the most likely explanation for these observations. These results are consistent with earlier studies showing that chloroform inhibits tumorigenesis in rodents.


Possible enhancing effect of the immunosuppressive agent, 6-mercaptopurine(6-MP) on focal lesion development in cirrhotic liver induced by carbon tetrachloride but not furfural in F344 rats. The modifying effects of an immunosuppressive agent, 6-mercaptopurine (6-MP), on development of focal lesions in liver cirrhosis models induced by carbon tetrachloride (CCl4) or furfural were studied in male F344 rats. Feeding of 6-MP at 50 p.p.m. for 20 weeks to animals with pre-existing liver cirrhosis caused immunosuppression, and significantly enhanced the induction of gamma-glutamyltranspeptidase (GGT)-positive foci and nodules in the CCl4 but not furfural case. Glutathione S-transferase P (GST-P)-positive preneoplastic lesions were not affected. Moreover, phenobarbital (PB) also enhanced the induction of GGT-positive hepatocellular lesions only in the CCl4-induced liver cirrhosis model, no promotion influence being exerted after treatment with the non-carcinogenic furfural. This study, therefore, suggests that 6-MP can enhance the induction of one type of preneoplastic foci and nodules and that essential differences exist between focal lesions arising in cirrhotic livers caused by CCl4 as opposed to furfural.


Characterization of the promotion of altered hepatic foci by 2,3,7,8-tetrachlorodibenzo-p-dioxin in the female rat. Previous studies have suggested that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) acts as a promoting agent in various organ systems including the rat liver. Since a major characteristic of the stage of tumor promotion is its operational reversibility, we have assessed whether TCDD-induced promotion is reversible in a two-stage model of hepatocarcinogenesis. In this model, female Fischer F344 rats were administered a single, intragastric dose of the initiating agent, diethylnitrosamine (DEN, 10 mg/kg), at the peak of proliferation induced by a partial hepatectomy. TCDD was then administered biweekly (0.14 micrograms/kg, s.c.) for 1, 3 or 5 months. One group of animals was killed at each of these time points, while a second group was maintained for each time point for an additional 6 months in the absence of further TCDD. Four serial frozen sections of liver were each stained with a different enzyme marker of altered hepatic foci (AHF). The AHF were identified and the number and volume fraction determined by quantitative stereology. Exposure to TCDD resulted in an increase in the number and size of AHF in the initiated relative to the uninitiated rats. Increasing the duration of promotion with TCDD led to an increase in the number of AHF per liver, the volume fraction of the liver occupied by AHF and the number of markers expressed aberrantly by a single AHF. Discontinuation of TCDD administration for 6 months before killing the animals resulted in a decrease in the total number of AHF observed, but those AHF that remained increased in size with an overall increase in volume fraction of AHF. Analysis of the size class distribution for AHF for each of the periods of TCDD promotion revealed an increase in the larger AHF but a decrease in the smaller, thereby resulting in an overall decrease in number of AHF with an increase in the volume fraction of AHF. Increasing the duration of the TCDD exposure prior to its withdrawal led to an increased AHF size, phenotypic complexity and number of AHF remaining after cessation of TCDD administration. Although the levels of TCDD in livers of rats 6 months after cessation of TCDD administration were still greater than background, they were markedly reduced compared to immediately after administration. Thus, cessation of exposure to TCDD after a brief duration led to a reversal of its promotional effects on the majority of AHF, while prolonged exposure led to maintained promotion of a minority of AHF.


A comparison of guanfacine, bunazosin, atenolol and nadolol on blood pressure and plasma noradrenaline responses to cold pressor testing. 1. The role of the presynaptic adrenoceptor subtypes in man was investigated based on observation of the changes in blood pressure (delta BP) and plasma noradrenaline concentration (delta NA) with the cold pressor test (CPT). 2. The CPT was well reproducible for BP and NA when performed at a 2 week interval in patients with mild hypertension. 3. After administration for 4 weeks, guanfacine (Gf; alpha 2-adrenoceptor agonist) decreased the delta NA response to CPT. 4. After administration for 2 or 4 weeks, bunazosin (Bu; alpha 1-adrenoceptor antagonist) atenolol (At; beta 1-adrenoceptor antagonist) and nadolol (Nd; non-selective beta-adrenoceptor antagonist) did not affect the delta NA response to CPT. 5. Both Gf and Bu decreased the systolic blood pressure response (delta SBP) to CPT after 4 weeks of the administration. Neither At nor Nd significantly changed the delta SBP response to CPT. 6. It is likely that Gf stimulated the presynaptic alpha 2 adrenoceptors at the sympathetic nerve endings as well as the central alpha 2 adrenoceptors, inhibiting the release of noradrenaline. It is unlikely that Bu, At and Nd exerted any clearly defined action on the presynaptic adrenoceptors in human hypertensive subjects.


Amlodipine combined with beta blockade for chronic angina: results of a multicenter, placebo-controlled, randomized double-blind study. Amlodipine, a potent long-acting dihydropyridine calcium antagonist, was compared with placebo in a parallel, randomized, double-blind study in 134 patients with chronic stable angina pectoris maintained on beta-adrenergic blocking agents. After a single-blind, two-week placebo period, patients were randomized to receive either amlodipine (2.5, 5, and 10 mg) or placebo once daily for four weeks. The effects of amlodipine on maximal exercise time, work, time to angina onset, and subjective indices including angina frequency, nitroglycerin tablet consumption, and patient and investigator ratings were assessed. Each dose of amlodipine produced increases in exercise time and calculated total work accomplished compared to baseline. Improvements at 5 and 10 mg were significantly greater than placebo which produced no significant change (p less than 0.05). Qualitative improvements in the severity of angina were produced by amlodipine at 5 and 10 mg daily assessed by patient-rating questionnaires (p less than 0.05). Reductions in angina frequency attacks per week and weekly nitroglycerin tablet consumption occurred but were not statistically significant when compared with placebo. Adverse effects observed during amlodipine treatment prompted discontinuation of treatment in only 2 out of 100 patients. Three patients discontinued treatment for reported lack of efficacy. No laboratory abnormalities prompted treatment discontinuation and minor side effects of dizziness, nausea, headache, and fatigue were observed infrequently. The results of this controlled, large-scale multicenter trial suggest that amlodipine significantly increased exercise capacity and was well tolerated when added to the antianginal regimen of patients remaining symptomatic while receiving beta-blocking agents.


The effects of beta blockade with (epanolol) and without (atenolol) intrinsic sympathomimetic activity in stable angina pectoris. The Visacor Study Group. Beta blockade constitutes efficient therapy for stable angina pectoris. The effects of lowering blood pressure and heart rate with such treatment are not always desired. Epanolol is a beta 1-selective partial agonist with minor effects on blood pressure and heart rate at rest. Atenolol is a pure beta 1-selective antagonist with more pronounced effects on blood pressure and heart rate at rest. The effects of epanolol, 200 mg o.d., and atenolol, 100 mg o.d., were compared in 173 middle-aged patients with stable angina pectoris in a randomized, double-blind, parallel group-controlled study for one year. No significant differences were shown in angina attack rate, nitrate consumption, or exercise performance. Resting heart rate and blood pressure were significantly lower on atenolol. Epanolol tended to be better tolerated than atenolol, as shown by visual analogue scales of well-being, activity, energy, and warm extremities, further supported by fewer reports on possible adverse reactions. In conclusion, epanolol appears to be as effective as atenolol and better tolerated in patients with stable angina pectoris.


Prevention of overuse injuries of the foot by improved shoe shock attenuation. A randomized prospective study. In a randomized prospective study among 390 recruits, the hypothesis that improved shoe shock attenuation could lessen the incidence of overuse injuries was tested. During the 14 weeks of training, 90% of the recruits sustained overuse injuries. Recruits training in a modified basketball shoe had a statistically significant lower incidence of metatarsal stress fractures and foot overuse injuries, compared with standard infantry boots, but their overall incidence of overuse injuries was not reduced. The effect of improved shoe shock attenuation was limited to those overuse injuries resulting from vertical impact loads.


Effects of catecholamines on the isolated aorta of the snake Bothrops jararaca. 1. Effects of catecholamines in snakes have been examined using an aorta preparation isolated from Bothrops jararaca. Adrenaline, noradrenaline and isoprenaline produced dose-dependent contractions on this preparation. The relative potency was adrenaline greater than noradrenaline greater than isoprenaline. 2. Phentolamine displaced, to the right, the concentration-response curve of the three catecholamines tested, showing the presence of alpha-adrenoceptors in this preparation. 3. Isoprenaline has never produced a relaxation, even when the aorta was first contracted by BaCl2 and pretreated with phentolamine, indicating that beta-adrenoceptors are absent in this preparation. 4. In this Bothrops jararaca preparation, exclusively neuronal uptake was found, thus demonstrating that its existence was preserved during evolution.


Hepatic metabolism of artemisinin drugs--III. Induction of hydrogen peroxide production in rat liver microsomes by artemisinin drugs. 1. In this communication, induction of hydrogen peroxide production by the semisynthetic antimalarial drugs of the artemisinin class (beta-arteether, beta-artelinic acid and dihydroartemisinin) in rat liver microsomes, is reported. 2. Endogenous, NADPH-dependent, production of hydrogen peroxide in rat liver microsomes was enhanced in the presence of arteether and artelinic acid, but not in the presence of dihydroartemisinin. 3. NADPH-dependent metabolism of arteether and artelinic acid was closely coupled to the drug-induced production of hydrogen peroxide. 4. The redox cycle of cytochrome P-450 was presented, which describes satisfactorily both the endogenous and the drug-assisted hydrogen peroxide production in rat liver microsomes; also, the rate-limiting step of the cycle was identified.


Effects of copper, cadmium and nickel on liver and kidney glutathione redox cycle of rats (Rattus sp.). 1. Glutathione redox cycle alterations induced by acute treatment of nickel, cadmium and copper, have been investigated in liver and kidney of adult male rats. 2. In liver, nickel treatment decreased GSH and GSSG levels, followed by a significant rebound in GSH content. Copper produced drastic reduction in the GSH/GSSG ratio, while cadmium treatment altered GSSG concentrations. 3. In kidney, the glutathione redox cycle remained unaltered after cadmium or nickel exposure, whereas copper caused similar changes to those observed in liver. 4. Hepatic glucose-6-P dehydrogenase and GSSG-reductase activities decreased after copper or nickel injection. GSH-S-transferase activity was altered in various ways, depending on the organ and the metal.


Influx of zinc by channel catfish (Ictalurus punctatus): uptake from external environmental solutions. 1. Channel catfish (Ictalurus punctatus) take up zinc (measured with 65Zn) from external ambient solutions in a concentration dependent manner. At a concentration of 10(-6)M Zn, this uptake is equivalent to 0.4% of the total body Zn each day. 2. Zinc influx was increased by external acid conditions (decreasing pH from 7.3 to 5). 3. Elevated Ca2+ and Cd2+, but not Al3+, concentrations markedly decreased the uptake of Zn. 4. These observations may be relevant to circumstances that occur under natural conditions, and influence the zinc nutrition and toxicity of the fish.