Relationship between antigens and IgG subclasses in bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disease characterized in part by the presence of tissue-bound and circulating antibodies (mostly of IgG) to the basement membrane zone (BMZ). We previously reported that IgG subclasses of BP antibodies were IgG1, IgG2 and IgG4, and that only BP IgG1 fixed complements. In this study, we examined whether BP IgG sub-classes bound to the same epitope of BP antigen or a different epitope. In an inhibition immunofluorescence studies, the complement fixing capability of IgG1 was inhibited by the pretreatment with IgG4 and partially inhibited by IgG2. On immunoblot analysis, IgG1 and IgG4 were bound to the same MW of BP antigen. In enzyme-linked immunosorbent assay (ELISA), the binding capability of IgG subclass fractions from patients with BP to synthetic peptide P1-2, exceeding normal IgG subclass fractions was seen in five IgG1, one IgG2 and two IgG4, from eight BP patients. The binding capability of IgG subclass fractions from the patients with BP to P1-1, exceeding the normal IgG fractions was seen in two IgG1, three IgG2 and one IgG4 from ten BP patients. On inhibition ELISA, the binding activity to P1-2 of IgG4 was partially inhibited by the pretreatment of IgG1 and IgG2. These findings suggest that BP IgG1, IgG2 and IgG4 could bind to the same epitope though considerable variation occurred between patients.

Anti-human IgE monoclonal antibodies recognizing epitopes related to the binding sites of high and low affinity IgE receptors

Anti-human IgE monoclonal antibodies (mAbs) were produced and eight clones recognizing epitopes on native IgE were selected. Epitopes were mapped by a competitive inhibition enzyme-linked immunosorbent assay, Western blotting and a multi-pin peptide technology. Four sites (one each in the C epsilon 1, C epsilon 2, C epsilon 2/C epsilon 3 junction and C epsilon 3) were recognized by the mAbs. The relationship between the four epitopes and the binding sites of high and low affinity IgE receptors (Fc epsilon RI and Fc epsilon RII, respectively) was studied using a monovalent Fab fragment of each mAb as a binding inhibitor. The IgE-Fc epsilon RII binding was clearly inhibited by the mAb recognizing the C epsilon 2/C epsilon 3 junction, suggesting that Fc epsilon RII binds to a rather limited area around the C epsilon 2/C epsilon 3 junction. The IgE-Fc epsilon RI binding, on the other hand, was scarcely inhibited by any single mAb. However, the binding was inhibited when the epitope in C epsilon 2 was blocked simultaneously with that at the C epsilon 2/C epsilon 3 junction or with that in C epsilon 3, indicating that these three distinct epitopes are related to the Fc epsilon RI binding sites. When these three epitopes were shown in the stereograph of human IgE, the Fc epsilon RI binding area was spread largely on the groove side between C epsilon 2 and C epsilon 3 domains. These results suggest that Fc epsilon RI acquires the high affinity through multiple bindings.

Generation and characterization of a human immunodeficiency virus type 1 (HIV-1) mutant resistant to an HIV-1 protease inhibitor

A synthetic peptide, RPI 312, that specifically inhibits the protease of the human immunodeficiency virus type 1 (HIV-1) showed a potent inhibition on virus production, maturation, and infectivity. Treatment with this agent prevented the cleavage of Gag protein at the site between p17 and p24 in HIV-1 chronically infected MOLT-4 cells as well as in the released virus. Passage of HIV-1 in the presence of gradually increasing concentrations of this protease inhibitor resulted in emergence of a variant that could evade the drug effects. In the resistant variant the maturation of Gag proteins appeared normal, but its infectivity was reduced compared with that of the parent virus. The nucleotides coding the amino acids at and around the cleavage site between Gag proteins p17 and p24 were not changed. One point mutation (A-->G) at site 2082 of the pol gene that resulted in one amino acid change at site 84 of the protease from isoleucine to valine (I-84-->V) could be detected in the resistant variant. An HIV-1 infectious DNA clone with the I-84-->V mutation also showed reduced sensitivity to this protease inhibitor. The findings that the resistant variant had lower infectivity and was still affected by higher doses of the drug support the speculation that resistance to protease inhibitors may not be as problematic as other drug resistance.

Retraction induced brain edema

A local cerebral retraction apparatus which simulates cerebral retraction was devised in an effort to clarify the relationship among the retraction pressure, somatosensory evoked potential (SEP) and cerebral blood flow (CBF) by measuring these parameters both simultaneously and chronologically. Twenty seven cats were divided into three groups according to the retraction pressure (10,30 and 50 mmHg, respectively). Each group underwent 30 minutes' retraction. At a retraction pressure of 10 mmHg, the reduction rate of CBF was low and the recovery of SEP was excellent. With an excessive pressure of 50 mmHg, both SEP and CBF reduced to 60% of the control value during the retraction and the recovery of SEP was extremely poor. Marked hyperemia of the brain surface was seen immediately after the release of retraction in more than 50% of the animals. At 30 mmHg, the recovery of SEP was moderately disturbed but, nevertheless, with a satisfactory value of more than 60% of the control. When the N1 component of SEP was abolished, the residual CBF showed approximately 60% of the control value, which seemed relatively high as compared to cases where cerebral artery were occluded. Extravasation of Evans blue which is an indication of vasogenic brain edema due to disruption of the blood-brain barrier, occurred extensively in the cerebral cortex involving a deep-lying white matter and an increase of the retraction pressure, corresponding to a poor recovery of neuronal function.

Augmentation of host defense mechanisms against tumor by sperabillin polymers, new basic peptidyl biopolymers, in mice

Sperabillin polymers, which have been shown recently to have antitumor activity, are new basic peptidyl polymers composed of a pseudo-peptide antibiotic, sperabillin A. The polymers, HP-2 (MW 9990), AP-2 (MW 20,100) and AB-2 (MW 35,000), were found to potently activate murine peritoneal macrophages. The phagocytosis-dependent respiratory burst and Fc gamma receptor expression of peritoneal macrophages from C57BL/6 mice were enhanced after in vitro cultivation with these polymers. When HP-2, a representative of these polymers, was intraperitoneally injected into mice, the number of peritoneal exudate cells increased and phagocytosis-dependent respiratory burst and class II (I-A) antigen expression of peritoneal macrophages were augmented. These macrophages showed strong inhibitory activity against the growth of murine tumor cell lines such as EL4 lymphoma and B16 melanoma. Nitrogen oxide, tumor necrosis factor (TNF) and interleukin 1 (IL-1) might be required for this inhibitory activity. Moreover, in mice treated with HP-2, splenocyte counts also increased and non-specific killer activity of the splenocytes was augmented. These results indicate that sperabillin polymers are new macrophage activators.

Crystallization and preliminary X-ray studies on pseudoazurin from Achromobacter cycloclastes IAM1013

New crystals of a blue copper protein, pseudoazurin from denitrifier Achromobacter cycloclastes IAM1013, have been obtained by means of vapor diffusion with ammonium sulfate as a precipitant at pH 6.0 and 4 degrees C. The crystals belong to the orthorhombic system, space group P2(1)2(1)2(1), with unit cell dimensions of a = 56.69(2), b = 61.53(2), and c = 30.20(1) A. The asymmetric unit includes one molecule of pseudoazurin with a Vm value of 2.04 A3/Da. The crystals are so stable against X-ray irradiation that a complete data set up to 1.54 A has been collected using a single native crystal. Solution of the structure was performed by means of the Patterson search techniques, and the current crystallographic R-factor is 17.5% at 3.0 A resolution. Refinement at higher resolution is in progress.

Protein phosphatase type 2B (calcineurin)-mediated, FK506-sensitive regulation of intracellular ions in yeast is an important determinant for adaptation to high salt stress conditions

To assess the physiological function of Ca(2+)-dependent protein phosphatase (PP2B) in the yeast Saccharomyces cerevisiae, the phenotypes of PP2B-deficient mutants were investigated. Although PP2B was dispensable for growth under normal conditions, the mutations did, however, cause growth inhibition under certain stress circumstances. The growth of the mutants was inhibited by NaCl and LiCl, but not by KCl, CaCl2, MgCl2 or nonspecific osmotic stresses. Upon shift to high NaCl medium, intracellular Na+ levels of both wild type yeast and the mutants initially increased at a comparable rate. However, internal Na+ in wild type cells started to decline more rapidly than the mutant cells during cultivation in high NaCl medium, indicating that PP2B is important in maintaining a gradient across the membrane. The protection against salt stress was achieved, at least in part, by the stimulation of Na+ export. The maintenance of a high level of internal K+ in high NaCl medium was also PP2B-dependent. In the presence of the immunosuppressant FK506, the growth behaviour and intracellular Na+ and K+ of wild type cells in high NaCl medium became very similar to those of the PP2B-deficient mutant in a manner dependent on the presence of the FK506 binding protein.

Simple assay system for detecting human T cell leukemia virus type I-binding cells and its application in titrating binding inhibitory antibodies

BACKGROUND

A simple and rapid assay system for the detection of human T cell leukemia virus type I (HTLV-I) binding cells was developed to assess the virus specific receptor and titrate the antibodies to block the virus binding.

EXPERIMENTAL DESIGN

Cells (5 x 10(5)) were incubated with 100 microliters of the concentrated HTLV-I at 37 degrees C for 1 hour. After washing, the cells were reacted with anti-HTLV-I envelope monoclonal antibody (rat) for 30 minutes on ice and then stained with fluorescein-isothiocyanate-conjugated anti-rat immunoglobulin. The stained samples were analyzed on FACScan. Antibody-titration of the virus-binding inhibition was carried out by pretreatment of the virus with serially diluted sera.

RESULTS

The specificity of the virus-binding was shown by dose-response relationship, kinetics of the binding, and temperature dependency. HTLV-I was absorbed onto a wide range of human cell lines and peripheral blood lymphocytes at various levels. Antibodies to inhibit the virus-binding were also quantitatively detected in sera from HTLV-I infected individuals, including asymptomatic carriers and patients with adult T cell leukemia or HTLV-I-associated myelopathy, but not from healthy seronegative controls.

CONCLUSIONS

This assay system would be useful in screening the virus-specific receptor and the neutralizing antibodies to HTLV-I. Thus, the assay could be applied to further studies on HTLV-I-related diseases.

[Genetic and epidemiologic studies on alcoholic liver diseases]

Polymorphic alleles of several genes such as ADH2, ALDH2, ApoB100, GST1, GST3 and ALAD were investigated from the aspect of the relationship with alcohol related diseases. DNAs were prepared from whole blood samples of 84 healthy controls (male), 70 patients (male) with alcohol related diseases and 87 patients (male) with non-alcoholic diseases. PCR technique was used for the detection of GST1 showed a good correlation to alcoholic liver diseases. The patients with alcoholic liver diseases had a higher frequency of ALDH2*1 than the healthy controls (p < 0.005). The frequencies of GST1 gene deletion in the samples were as follows: Healthy controls; 47.6%, alcoholic liver diseases (fibrosis: 75%, cirrhosis: 65.5%, hepatoma: 75%) and non-alcoholic liver diseases: 54%. The data indicated that the patients with alcoholic liver diseases had a significantly higher frequency of gene deletion than the healthy controls (p < 0.005). In addition, homozygote of ALAD1 allele detected by MpsI-RFLP showed a good correlation to alcoholic liver diseases. Thus, the genetic polymorphism of ALDH2, GST1 gene deletion and ALAD can be applied widely for the study of genetic association with alcoholic liver diseases.

Analysis of 3' terminals of human immunodeficiency virus type 1 transcripts in persistently infected cells

To examine the 3' terminal processing of human immunodeficiency virus type 1 (HIV-1) transcripts and the effects of phorbol ester (TPA) on this processing, cellular RNAs from persistently infected T cells (MOLT-4) or promonocytes (U937), with or without TPA treatment, were analyzed. To map the 3' terminals of viral transcripts, the RNA samples were examined by RNase-protection assay with an HIV-1 long terminal repeat (LTR) antisense riboprobe. Without TPA treatment, the viral transcripts initiated at the cap site in 5' LTR and polyadenylated at poly(A) site in 3' LTR were dominantly detected in both types of cells. This analysis demonstrated that some occlusion mechanism inactivating the poly(A) site in 5' LTR might exist in these infected cells. After TPA treatment, we found a dramatic shift in the protected patterns of viral transcripts in MOLT-4 cells, while the shift in U937 cells was less dramatic. These results suggested that the primary factor(s) involved in the observed effect of TPA might be cellular. We also demonstrated that the shift in the protected patterns of viral transcripts was associated with increased steady-state levels of viral transcripts. These results indicated that the factors involved in the TPA-induced shift might have some relation to the trans-activation of HIV-1 by similar substances.

Transdermal administration of emedastine

Transdermal administration of emedastine was tested in vitro and in vivo. In the diffusion cell method in vitro, emedastine free base was more permeable by transdermal administration than emedastine difumarate. Emedastine had higher permeability in hydrophobic vehicles than in hydrophilic vehicles, and was most permeable in fatty acid monoesters. It was suggested that the change in permeability of emedastine from these vehicles was dependent on the change in its partition from the vehicle to the skin. In studies using rabbits in vivo, emedastine had high permeability from fatty acid monoesters and fatty acid diesters as found in in vitro studies, and bioavailability of the drug after transdermal administration was greater than that after peroral administration. The flux of emedastine in vitro was correlative with the pharmacokinetic parameters in vivo. Consequently, it is clear that transdermal permeability of emedastine is very high and that the drug may be efficacious in the system after administration by these means.

Effect of recombinant human erythropoietin administration on immunological indices in patients undergoing chronic hemodialysis

In patients undergoing chronic hemodialysis, marked anemia may cause decreased immunological function. To improve this anemia, we investigated the effect on immunological indices of recombinant human erythropoietin (rHuEPO) administration in 24 hemodialysis patients (13 males and 11 females) with renal anemia complications. Their mean age was 54.9 +/- 14.8 years and the mean duration of dialysis was 100.5 +/- 54.9 months. The subjects were treated with rHuEPO for 12 months, which helped to maintain a hematocrit value elevated by 5% from the baseline. Cell-mediated immunity and humoral immunity were assessed prior to as well as throughout the treatment period. Of the total number of patients studied, the anemia of 16 improved while 8 did not show signs of sufficient improvement. The improved group showed an increase in in vitro lymphocytic response to phytohemagglutinin (PHA), CD4/CD8, CD16 and serum IgM levels, while the CD8 level decreased significantly. Improvement in the general physical condition with rHuEPO treatment appeared to be associated with the changes in immunological indices, but the precise mechanism remains obscure.

Expression of the target antigen for cytotoxic T lymphocytes on adult T-cell-leukemia cells

Adult T-cell-leukemia (ATL) cells were examined for susceptibility to human T-cell-leukemia virus type I (HTLV-I) tax-specific cytotoxic T lymphocytes (CTL) derived from a patient with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). These CTL efficiently killed HLA-matched leukemia cells of an ATL patient after overnight incubation. However, ATL cells immediately after isolation from the peripheral blood were only marginally susceptible to the CTL. This is not due to inappropriate expression of major-histocompatibility-complex (MHC)-class-I antigen on the leukemia cells. Addition of synthetic peptide, corresponding to the CTL epitope, to the assay enabled the CTL to kill the fresh ATL cells. Scarcity of HTLV-I antigens in the fresh ATL cells and induction of these antigens by in vitro incubation were demonstrated both on the cell surface and in the cytoplasm. Lectin stimulation augmented synthesis of HTLV-I antigens, but was not essential for the induction. The presence in the culture of human plasma containing a high titer of antibodies to HTLV-I did not affect the induction of HTLV-I expression in the ATL cells. Furthermore, significantly lower levels of HTLV-I tax mRNA were present in the fresh ATL cells than in the cultured ATL cells, whereas the levels of HTLV-I proviral tax gene did not differ among these cells. This suppression of HTLV-I transcription in fresh ATL cells accounts for resistance to the CTL, and could be a reason for the persistence of HTLV-I infection in vivo.

Effects of a novel orally effective V1-receptor antagonist, OPC-21268, on AVP-induced sympathoinhibition

Arginine vasopressin (AVP) plays as important role in control of circulation and may be involved in pathophysiology of cardiovascular diseases. Recently a novel oral V1-receptor antagonist, OPC-21268, has been produced for possible human therapeutic use (Y. Yamamure et al. Science Wash. DC 252: 572-574, 1991). OPC-21268 is a nonpeptide antagonist and inhibits AVP-induced vasoconstriction in rats and humans. In this study, we examined the influence of OPC-21268 on the sympathoinhibitory and bradycardic effects of AVP in conscious rabbits. Before OPC-21268, AVP at doses of 1, 3, 10, and 30 mU/kg decreased renal sympathetic nerve activity (RSNA) by 24 +/- 5, 40 +/- 5, 65 +/- 6 and 86 +/- 5%, respectively, and decreased heart rate from 243 +/- 10 beats/min at control to 232 +/- 11, 221 +/- 10, 197 +/- 9, and 166 +/- 6 beats/min, respectively (n = 12). Oral OPC-21268 at 30 mg/kg (n = 12) and 90 mg/kg (n = 5) did not alter the baseline values of arterial pressure, heart rate, and RSNA. After oral OPC-21268 the decreases in RSNA and heart rate evoked with AVP at graded doses were partially but significantly attenuated (P < 0.01). The attenuation of the AVP-induced decreases in RSNA and heart rate was similar between the two doses of OPC-21268. In another group of rabbits (n = 6), intravenous OPC-21268 at 30 mg/kg almost completely abolished AVP-induced decreases in heart rate and RSNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of insulin-degrading enzyme increases translocation of insulin to the nucleus in H35 rat hepatoma cells: evidence of a cytosolic pathway

We previously demonstrated the translocation of insulin to the nucleus in several cell types and partially characterized the uptake mechanisms and pathways in H35 rat hepatoma cells. Nuclear accumulation of insulin was energy independent, time and temperature dependent, and apparently was not saturable at insulin concentrations which resulted in full receptor occupancy. We also have shown insulin could be internalized by both receptor-mediated and fluid-phase endocytosis. This study investigated subsequent steps involved in the nuclear accumulation of insulin following internalization. We examined the effects of inhibiting insulin degrading enzyme (IDE) with 1,10-phenanthroline on the nuclear accumulation of insulin in H35 cells. 1,10-phenanthroline (2 mM) which markedly inhibited insulin degradation, significantly increased nuclear accumulation of insulin without having any effects on total cell-associated and intracellular insulin. This reagent increased 125I-insulin on the cellular membrane and decreased 125iodine (125I-insulin and 125I-insulin degradation products) in the cytosolic fractions. Chemical extraction and Sephadex G-50 chromatography revealed the insulin associated with the nucleus in 1,10-phenanthroline-treated cells formed the same complex(es) with the nuclear matrix as in control cells. These results suggested that inhibition of cytosolic IDE activity resulted in increased insulin translocation from the cytosol to the nucleus. Furthermore, when IDE activity was inhibited by high cytosolic insulin concentrations, the amount of 125I-insulin in the nucleus was significantly increased. Our study suggests internalized insulin is probably released from endosomes into the cytosol where modulation of IDE activity could have significant effects on the accumulation of insulin, or insulin-cytoplasmic protein complexes, in nuclei. The IDE regulatory mechanism, by controlling the translocation of insulin to the cell nucleus, could play a crucial role in insulin's regulation of gene expression and cell proliferation.

In vitro modification of human immunodeficiency virus type 1 (HIV-1) infectivity by the U937 cells

The effect of host cell factors on infectivity of human immunodeficiency virus type 1 (HIV-1) was studied by infecting a monoblastoid cell line (U937) or a T-cell line (MOLT-4) with a highly infective single clone of HIV-1 and comparing the infectivity of the produced viruses to different cell lines. Chronically infected U937 cells consistently produced viruses with minimal infectivity. This phenotypic change was host-dependent as the back-passage of the U937-produced low infective viruses into MOLT-4 cells resulted in regaining their original high infectivity. Southern and Northern blot analyses of the HIV-1 grown in U937 cells did not reveal any genomic difference between it and the virus grown it MOLT-4 cells. The radioimmunoprecipitation analysis of viral proteins showed that the HIV-1-infected U937 cells had a different pattern of envelope glycoproteins and core proteins, which well correlated with the low infectivity of the produced viruses. This experimental system using MOLT-4 and U937 cell lines would be useful to further explore host cell factor(s) which play an important role in the regulation of HIV-1 infectivity.

Chemistry and anti-tumor activity of sperabillin polymers

Sperabillin A, 3-[[(3R,5R)-3-amino-6-[(2E,4Z)-2,4-hexadienoylamino]- 5-hydroxyhexanoyl]amino]propanamidine dihydrochloride, was polymerized on standing for several days under a highly humid atmosphere or in the presence of radical initiators. The average molecular weight of the polymers obtained could be regulated by changing the reaction conditions in the latter case. Spectral analyses of the polymers revealed that the 2,4-hexadienoyl moiety of sperabillins was polymerized in a free radical-initiated reaction. The polymers selectively inhibited the proliferation of human umbilical vein endothelial (HUVE) cells. Polymers having higher molecular weight showed stronger inhibition of HUVE cell proliferation. In addition, the polymers showed anti-tumor activity against B16 melanoma in vivo.

Synthesis and antimicrobial activity of sperabillin derivatives

Modification of sperabillins was carried out. The 2-amidinoethylamino moiety was removed by brief acidic hydrolysis. The 2,4-hexadienoyl moiety was hydrogenated to the hexanoyl moiety and this was cleaved by an enzymatic reaction using the cells of Pseudomonas acidovorans IFO 13582. The 2-amidinoethylamino and the 2,4-hexadienoyl moieties were replaced with other groups. The derivative which was prepared by condensation of two molar amounts of dehexadienoylsperabillin A with (E,E)-muconic acid showed better protective effects than sperabillin A against Gram-negative bacteria.

Production of chronic congestive heart failure by rapid ventricular pacing in the rabbit

OBJECTIVE

The aim was to produce a model of low output congestive heart failure by rapid pacing in rabbits.

METHODS

To perform rapid pacing in rabbits, a custom made pacemaker was developed which is light (about 80 g) and can pace at up to 400 beats.min-1 for more than two weeks. A thoracotomy was done and two electrodes were sutured onto the left ventricle. A central venous pressure line was chronically implanted. With the use of this pacemaker, rabbits were paced at 350-400 beats.min-1 for several weeks.

RESULTS

Central venous pressure increased from 1.4(SEM 0.2) to 6.4(0.5) mm Hg (p < 0.01, n = 14). After pacing for 16.1(1.6) d, haemodynamic studies were performed under anaesthesia with thiamylal sodium. Left ventricular end diastolic pressure was higher in the paced rabbits (n = 10) than in the control rabbits which underwent sham operation but were not paced (n = 6), at -0.6(0.6) v 19.3(2.0) mm Hg (p < 0.01). Cardiac output [673(56) v 536(45) ml.min-1, p < 0.10] and +dP/dt [1433(97) v 722(51) mm Hg.s-1, p < 0.01] were lower in the paced rabbits (n = 7-8) than in the control rabbits (n = 6). The paced rabbits had more ascites [1.9(1.0) v 45.9(18.9) ml, p < 0.05] and pleural effusion [0.4(0.3) v 12.9(6.7) ml, p < 0.10] than control rabbits. Plasma noradrenaline was higher in the paced rabbits (n = 11) than in the control rabbits (n = 7), at 1.59(0.43) v 0.60(0.05) ng.ml-1 (p < 0.05). The ratio of wet heart weight or lung weight to body weight was higher (p < 0.01) in the paced rabbits than in the control rabbits.

CONCLUSIONS

Chronic biventricular congestive heart failure can be produced in rabbits by rapid pacing.

Crystallization and preliminary X-ray studies of a protease from Pseudomonas aeruginosa

A protease produced by Pseudomonas aeruginosa has been crystallized by the vapor-diffusion method using polyethylene glycol 4000 as a precipitant. The crystals belong to the hexagonal space group P6(1) (P6(5) with unit cell dimensions; a = b = 106.9 A, c = 96.9 A. There are two molecules per asymmetric unit. The crystals diffract X-rays to at least 3.0 A and are suitable for X-ray crystallographic studies.

Relationship between alcohol consumption and the activity of GTP-binding regulatory proteins in human erythrocyte membranes

Activity of stimulatory GTP-binding regulatory protein (Gs) in human erythrocyte membranes was assessed by activation of adenylate cyclase in S49 murine lymphoma variant cells to elucidate a relationship to alcohol consumption. In apparently healthy subjects, alcohol consumption < 50 g ethanol per week did not alter the Gs activity, but it was significantly higher (14.3%, P < 0.05) in moderate drinkers (50-150 g/week) than non-drinkers. Then, the Gs activity declined with a further increase in alcohol consumption (150-550 g/week). Those subjects with drinking levels of > 50 g/week also showed significant increases in other alcohol-related markers, Na+, K(+)-ATPase and gamma-glutamyltransferase. The Gs activity was significantly low in alcoholics (a 34.9% reduction). No such reduction was noted in patients with other diseases. The results indicate that the Gs activity in erythrocyte membranes is an alcohol-related marker in humans. The variation of Gs activity is distinctive from those of other alcohol-related markers.

Inhibition of nitric oxide formation in the nucleus tractus solitarius increases renal sympathetic nerve activity in rabbits

It has been shown that nitric oxide (NO) is synthesized in the central nervous system as well as in vascular endothelial cells. However, the physiological role of NO in cardiovascular regulation by the central nervous system remains unclear. This objective of this study was to examine the possibility that NO plays a role in neural transmission in the nucleus tractus solitarius (NTS) and thus contributes to control of sympathetic nerve activity in rabbits. We examined the effects of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of the formation of NO from L-arginine, microinjected into the NTS on arterial pressure (AP), heart rate (HR), and renal sympathetic nerve activity (RSNA). L-NMMA increased AP and RSNA in rabbits with intact as well as denervated sinoaortic baroreceptors and vagi. L-NMMA increased HR only in rabbits with sinoaortic denervation and vagotomy. Pretreatment with L-arginine microinjected into the NTS, which did not alter baseline AP, HR, and RSNA, prevented the increases in AP and RSNA evoked with subsequent L-NMMA. Pretreatment with D-arginine did not alter the effects of subsequent L-NMMA injections into the NTS. The gain of arterial baroreflex control of RSNA assessed by the slope of the regression line relating changes in AP and those in RSNA caused by intravenous phenylephrine or nitroglycerin did not differ before and after microinjections of L-NMMA. L-NMMA microinjected into the area postrema did not alter AP, HR, or RSNA. These results suggest that in rabbits NO is involved in the mechanism in the NTS that mediates tonic inhibition of RSNA.(ABSTRACT TRUNCATED AT 250 WORDS)