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)

Ferrocins, new iron-containing peptide antibiotics produced by bacteria. Isolation, characterization and structure elucidation

Novel iron-containing peptide antibiotics, ferrocins A, B, C and D, have been isolated from the culture filtrate of Pseudomonas fluorescens YK-310. These antibiotics were purified by butanol extraction, followed by column chromatography using adsorption resin, silica gel and preparative reverse-phase HPLC. The structures of ferrocins were elucidated using spectroscopic and degradative methods. Ferrocins contain three hydroxamate moieties per ferric ion which forms an octahedral iron complex.

Modulation of host cell nuclear proteins that bind to HIV-1 trans-activation-responsive element RNA by phorbol ester

The trans-activation-responsive (TAR) element located within the 5' untranslated region of HIV-1 mRNA is the cis-responsive element for Tat, the viral trans-activator protein. Several TAR RNA binding proteins (TRBPs) have been identified in the nuclear extract from HeLa cells as cellular factors required for a full Tat-mediated trans-activation. In this study, we have tried to identify TRBPs in human T cell line (MOLT-4) persistently infected with HIV-1. Nuclear extract from the infected MOLT-4 cells was analyzed by gel-retardation and uv cross-linking assays with radiolabeled TAR RNA probe. Two major complexes of TAR RNA with some cellular proteins were detected in the gel-retardation assay. As the components of these complexes, at least five TRBPs (p30, p37, p46, p50, and p56) showing specific binding to the TAR RNA were detected in the uv cross-linking assay. We also observed that the detectable levels of p37 and p50 in the infected MOLT-4 cells were greatly reduced after phorbol ester (TPA) treatment under the condition of which HIV-1 gene expression was increased by about fivefold. These results suggest that the modulation of TRBPs by some mitogenic stimuli such as TPA might have a role in the trans-activation of HIV-1 gene expression in vivo.

Ferrocins, new iron-containing peptide antibiotics produced by bacteria. Taxonomy, fermentation and biological activity

A Gram-negative bacterium was found to produce new iron-containing peptide antibiotics, ferrocins A, B, C and D, and the producing bacterium was characterized and identified as Pseudomonas fluorescens YK-310. These new antibiotics showed antibacterial activity against Gram-negative bacteria in vitro. Although the ferrocins showed similar antibacterial activity against both Escherichia coli and Pseudomonas aeruginosa on the standard assay media, they showed strong therapeutic effects selectively against P. aeruginosa in experimentally infected mice.

Immunohistochemical analysis of keratin distribution in eccrine poroma

Although eccrine poroma has been thought of as a neoplasm of the intradermal eccrine duct, this interpretation has not been entirely confirmed. In this study, twenty-five cases of eccrine poroma were retrieved and analyzed by immunohistochemical techniques, using various kinds of monoclonal antikeratin antibodies. Comparative immunohistochemical observations of eccrine poroma and normal eccrine glands revealed that the poroma cells expressed immunophenotypes similar to those of the basal cells of dermal eccrine ducts. Sweat-ductlike structures showed similar staining patterns to those observed in the inner cells of dermal eccrine ducts. Some cystic spaces were similar to those observed in the secretory cells of eccrine glands. Eccrine poroma is, therefore, speculated to originate via the proliferation and expansion of the basal cells of eccrine ducts, although it is very difficult to prove the histogenesis. Some tumor cells may differentiate toward inner cells of the eccrine ducts, forming ductal lumina, whereas other tumor cells differentiate toward eccrine secretory regions, forming some cystic spaces.

New strategy for detection of ALDH2 mutant

Genetic polymorphism of the ALDH2 gene was analysed according to a new technique designated as amplification created restriction site (ACRS). A restriction site for the enzyme (Mbo II) was artificially created in the amplification product using an oligonucleotide primer possessing one mismatched base. Analysis using ACRS technique concerning 41 healthy controls and 63 alcoholics with liver diseases confirmed that the ALDH2 mutant was significantly lower in alcoholics than in healthy controls.

Membrane-spanning Fc gamma receptor III isoform expressed on human placental trophoblasts

PROBLEM

Fc receptor for immunoglobulin (Fc gamma R) is an important mediator of immunological functions in the feto-maternal relationship. We have demonstrated by immunohistochemical means that three distinct classes of Fc gamma Rs are expressed in the different cell components of the human placenta.

METHOD

In this study, Fc gamma RIII isoform expressed on placental trophoblasts (PTs) was investigated by indirect immunofluorescence and cDNA cloning. PTs, isolated from human term placenta by digestion with proteolytic enzyme, were reacted with monoclonal antibodies (MAb) against the Fc gamma Rs and other surface markers of leukocytes and subjected to flow cytometric analysis.

RESULTS

PTs were positively stained with 3G8 and Leu1 1b against Fc gamma RIII, partially stained with MAb against MHC class I, but not with 32.2 (Fc gamma RI), IV3 (Fc gamma RII), or MAbs against CD4, CD19, or CD56, indicating that only low affinity receptor, Fc gamma RIII, is expressed on PTs. The DNA sequence of cloned Fc gamma RIII CDNA from PTs by PCR was identical to that of natural killer (NK) cell isoform, including the position of the stop codon that differs from the granulocyte isoform by several nucleotide substitutions. We further analyzed the susceptibility of PTs against phosphatidylinositol specific phospholipase C (PI-PLC) to determine the structural topology of PT isoform. While the reactivity with 3G8 on PTs was not influenced by treatment with PI-PLC, that on granulocytes was significantly diminished with PI-PLC.

CONCLUSIONS

This result confirmed that Fc gamma RIII on PTs is a membrane-spanning molecule, and that it is distinctive from PI anchoring Fc gamma RIII on granulocytes.

Investigation of alcohol dehydrogenase isozymes of biopsy gastric mucosa in Japanese

Several milligrams of biopsy samples of the gastric mucosa from the body, the angulus and the antrum of the stomach from 32 Japanese (14 males and 18 females, 32-90 years old) were examined using isoelectric focusing combined with a sensitive and specific staining method for the detection of sigma-ADH isozyme variation. In addition, differences of isozyme activity were analyzed from the aspects of age and gender. The isozyme bands of sigma-ADH in regions of the body as well as the angulus showed detectable activity, but there was weak or no activity in the antrum in all 32 individuals. These observations were inconsistent with the previous report that sigma-ADH in polymorphic in the manner of presence or absence of isozyme bands in Japanese. sigma-ADH activity was higher in males than in females and decreased the higher age group. Consequently, sigma-ADH was not polymorphic in Japanese and the activity of sigma-ADH was influenced by factors such as anatomically distinct areas and ageing, as well as gender.

Nonreceptor mediated nuclear accumulation of insulin in H35 rat hepatoma cells

We previously demonstrated that insulin accumulated in 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, temperature, and insulin concentration dependent, but apparently nonsaturable. This study investigated further the initial endocytotic pathways that contribute to the nuclear accumulation of insulin using trypsin treatment of the cells to prevent insulin binding to its plasma membrane receptor. Total cell-associated, intracellular, and nuclear insulin were compared in control and trypsin-treated H35 hepatoma cells. Trypsin treatment markedly decreased total cell-associated and intracellular insulin as well as the nuclear accumulation of insulin when cells were incubated with 2.8 ng/ml insulin. When the cells were incubated with 100 ng/ml insulin, trypsin treatment totally inhibited insulin binding to the plasma membrane for at least 90 min. However, intracellular accumulation of insulin was reduced by only 50% at 60 min, and trypsin treatment failed to inhibit the nuclear accumulation of insulin. Chemical extraction and Sephadex G-50 chromatography revealed nuclear associated insulin in trypsin-treated cells was identical to that in control cells incubated with either 2.8 or 100 ng/ml insulin. These results suggest that a nonreceptor mediated uptake pathway, i.e., fluid-phase endocytosis, contributed significantly to the nuclear accumulation of insulin at high insulin concentrations, but at lower insulin concentrations the receptor-mediated pathway predominated. No matter which initial endocytotic route was used to internalize insulin, the insulin apparently associated with the same nuclear matrix proteins. This association of insulin with the nuclear matrix may be involved in regulation of nuclear events such as cell growth and differentiation or gene transcription.

Purification of bullous pemphigoid IgG subclasses and their capability for complement fixation

The antibody reactivity and complement fixing capability of circulating IgG subclass antibodies of patients with bullous pemphigoid (BP) were investigated. Four subclasses of polyclonal IgG were purified from the sera of BP patients. The first stage of purification was a combination of chromatographies on DEAE Affi-Gel Blue and protein A-Cellulofine columns. The four polyclonal IgG subclasses were then isolated from the above-mentioned semi-purified subclass fractions using IgG subclass-specific immuno-affinity chromatographies. Using an immunohistopathological technique, IgG deposits were detected at the basement membrane zone (BMZ) in the normal skin incubated with IgG subclasses other than IgG3. C3 deposits were detected at BMZ in the skin incubated with IgG1. Neither IgG nor C3 deposits were in skin incubated with IgG3. These findings suggest that the subclasses of circulating BP antibodies are IgG1, IgG2 and IgG4, but not IgG3. Moreover, only the BP IgG1 subclass appears to fix complement.

Direct stimulation of immediate-early genes by intranuclear insulin in trypsin-treated H35 hepatoma cells

H35 hepatoma cells were treated with trypsin to abolish insulin binding and insulin-stimulated receptor kinase activity. Insulin was, however, internalized by fluid-phase endocytosis in trypsin-treated cells. Furthermore, nuclear accumulation of insulin was similar in control and trypsin-treated hepatoma cells. Northern blot analysis revealed insulin increased g33 and c-fos mRNA concentrations identically in control and trypsin-treated cells but had no effect on beta 2-microglobulin mRNA. Actinomycin D treatment prior to or after insulin addition demonstrated that insulin increased gene transcription and had no effect on mRNA degradation. These studies suggest that the accumulation of intact insulin in cell nuclei may be directly involved in the increased transcription of immediate-early genes.

[Recurrent fusiform aneurysm of the internal carotid artery; a case report]

A 61-year-old woman was referred to our department on February 12, 1991, due to a fusiform aneurysm of her left internal carotid artery (ICA). She had received aneurysm surgery twice in other hospitals in the past. The first operation, in June, 1980, was for an unruptured, symptomatic left internal carotid-posterior communicating aneurysm and the aneurysm disappeared completely after the neck clipping procedure was carried out by one of the authors. In November, 1990, she suffered from subarachnoid hemorrhage with a hematoma in the left frontal lobe. A ruptured anterior communicating aneurysm was clipped in another hospital, where abnormal dilatation of the left ICA was pointed out. She was referred to our department after a ventricular peritoneal shunt operation. Though the postoperative angiogram performed in 1980 had shown complete disappearance of the left IC-PC aneurysm, it was presumed that the fusiform aneurysm which she presented at our department was recurrent because it existed in almost the same place as the aneurysm which had been clipped. It was also in contact with a clip applied in 1980. In accord with the patient's desire to receive surgery, the fusiform aneurysm was operated on directly, and it was remarkably reduced in size by dome clipping. During a clip, a Sugita booster clip was useful for preventing a slip-out of the clip applied on the aneurysmal dome. The patient was discharged about 20 days after the operation and returned to her usual life. A recurrent fusiform aneurysm of the ICA arising after the neck clipping of IC-PC aneurysm has rarely been encountered.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of L-arginine on forearm vessels and responses to acetylcholine

This study was designed to investigate the effects of L-arginine (the substrate of endothelium-derived nitric oxide) in human forearm vessels. We examined whether intra-arterial infusion of L-arginine dilated forearm vessels and augmented vasodilatory responses to acetylcholine in young, healthy humans. The left brachial artery was cannulated for drug infusions and direct measurement of arterial pressure. Forearm blood flow was measured by a strain gauge plethysmograph. Intra-arterial infusions of L-arginine at 10, 20, 40, and 60 mg/min increased forearm blood flow from 4.7 +/- 0.6 to 4.9 +/- 0.5, 5.7 +/- 0.5, 7.2 +/- 0.8, and 8.2 +/- 0.9 ml.min-1.100 ml-1, respectively (n = 8, p less than 0.01), whereas D-arginine at the same doses did not alter forearm blood flow (n = 7). Intra-arterial infusions of acetylcholine (n = 7) (4, 8, 16, and 24 micrograms/min) and sodium nitroprusside (n = 5) (0.2, 0.4, 0.8, and 1.2 micrograms/min) increased forearm blood flow dose dependently (p less than 0.01 for both). Arterial pressure was not altered with infusions of these drugs. Responses to acetylcholine were augmented with simultaneous intra-arterial infusion of L-arginine at 10 mg/ml (p less than 0.01) but not with D-arginine. Responses to sodium nitroprusside were not altered by L-arginine. These results in human forearm resistance vessels support the notion that vasodilation induced by acetylcholine is a result of the conversion from L-arginine to endothelium-derived nitric oxide.(ABSTRACT TRUNCATED AT 250 WORDS)

Mutations in genes for acetylcholinesterase intensify lethality by acrylamide in Caenorhabditis elegans

Acrylamide inhibits growth and results in death in the nematode Caenorhabditis elegans. The lethargic effect is marked in the mutants defective in genes for acetylcholinesterase (AChE) and the effect is approximately parallel with the decrease in AChE activity by mutations. Although neither the activity nor the localization of the enzyme is affected by acrylamide, the acetylcholine level was significantly elevated.

Detection of GST1 gene deletion by the polymerase chain reaction and its possible correlation with stomach cancer in Japanese

A homozygous gene deletion at the GST1 locus of genomic DNA isolated from peripheral blood was investigated for its relationship with several types of cancer using the polymerase chain reaction (PCR) technique. DNA samples were prepared from blood obtained from 128 healthy blood donors and 150 patients with cancer or chronic hepatitis. PCR primers were prepared based on the human cDNA sequence and the intron/exon sequences of the rat Yb2 gene. The amplified sequence between exons 5 and 6 including intron 5 showed very clearly the presence of absence of the GST1 gene, after electrophoresis in a 2% agarose gel. Segregation of the presence and absence of PCR product from samples of twins and their parents indicated that presence involves homozygous or heterozygous normal GST1 genotypes while absence involves only homozygous gene deletion. The patients with stomach cancer had a significantly higher frequency of gene deletion than did the healthy controls (P < 0.005). Thus, GST1 deletion may be a possible genetic marker for early detection of a group at high risk of stomach cancer.

Arterial baroreflex dynamics in normotensive and spontaneously hypertensive rats

To investigate dynamic or frequency-dependent characteristics of arterial baroreflex control of efferent sympathetic nerve activity in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY), we assessed the transfer function from aortic pressure (AP) to renal sympathetic nerve activity (RSNA) using a "white-noise technique." In pentobarbital sodium-anesthetized rats, we recorded RSNA as the output, while AP was randomly perturbed to impose input pressure changes with broad frequencies. We calculated the transfer function from AP to RSNA over the frequency range of 0.01-5 Hz through the spectral analysis of the input and output. The results indicated that the gain, phase shift, and coherence of the transfer function for SHR and for WKY were similar and statistically indistinguishable. The gain was relatively constant below 0.05 Hz but increased steadily by fivefold as frequency increased in the frequency range of 0.05-0.8 Hz. The phase was out of phase where coherence was high. The coherence was high (greater than 0.5) in the frequency range of 0.04-0.8 and 1.00-1.03 Hz but was low in other frequencies. These results suggest that dynamic or frequency-dependent characteristics of arterial baroreflex control of RSNA were not altered in SHR as compared with WKY.

Captopril improves impaired endothelium-dependent vasodilation in hypertensive patients

Animal studies suggest that some angiotensin converting enzyme inhibitors augment endothelium-dependent vasorelaxation. We aimed to determine if captopril augments endothelium-dependent vasodilation in middle-aged hypertensive patients. By using strain-gauge plethysmography, forearm vasodilation evoked with intra-arterial acetylcholine (4, 8, 16, and 24 micrograms/min) or nitroprusside (0.2, 0.4, 0.8, and 1.2 micrograms/min) was examined before and after captopril administration (25 mg per os). Before captopril, forearm vasodilation with acetylcholine was less in hypertensive patients (n = 12) than in age-matched (n = 7) or young (n = 7) normotensive subjects, but forearm vasodilation with nitroprusside did not differ among the three groups. Captopril improved forearm vasodilation in hypertensive patients (n = 7) with acetylcholine but nitroprusside did not. In contrast, nifedipine (10 mg per os) did not alter forearm vasodilation with acetylcholine or nitroprusside in hypertensive patients (n = 5). The decreases in mean blood pressure caused by captopril and nifedipine in hypertensive subjects were comparable. Captopril did not alter forearm vasodilation with acetylcholine or nitroprusside in young normotensive subjects (n = 7). These results suggest that captopril in hypertensive patients may acutely improve impaired endothelium-dependent forearm vasodilation that does not result from reduction in blood pressure per se.

Monoclonal antibodies against human alpha-fetoprotein more reactive to cell-surface alpha-fetoprotein than to free alpha-fetoprotein

This paper describes the finding of monoclonal antibody (MoAb) more reactive to cell-surface alpha-fetoprotein (AFP) than to free AFP by using a simple in vitro system. Twelve mouse MoAbs, ten IgG1, one IgG2a and one IgG2b, against human AFP from hepatocellular carcinoma were obtained by the cell fusion technique. Each hybridoma supernatant was assayed by enzyme-linked immunosorbent assay (ELISA) to solid-phase AFP. The assay results showed that two MoAbs, 67D and 80G, were most reactive to AFP. 80G had a higher affinity constant than 67D, while the both reactions were similarly difficult to inhibit by free AFP in ELISA. 67D and 80G reacted with AFP on the surface of ethanol-fixed cells from the human hepatoma cell line HuH-7 and this reaction was also difficult to inhibit by free AFP in Cell ELISA. Furthermore, Western blot analysis showed that 67D and 80G were more reactive to membrane-bound AFP than other antibodies. These findings first suggest that there could be anti-AFP MoAbs preferably binding to cell-surface AFP rather than to serum AFP.

Expression of the amino-terminal half of the NS1 region of the hepatitis C virus genome and detection of an antibody to the expressed protein in patients with liver diseases

A cDNA fragment encompassing the 5'-terminal half of the NS1 region of the hepatitis C virus (HCV) genome was cloned. The cDNA was expressed in insect cells using a recombinant baculovirus, and a protein band of approximately 21K was identified by immunoblotting with a serum sample from a patient with chronic hepatitis C. Antibody to the protein was detected in sera from 13.4% of patients with chronic non-A, non-B hepatitis (NANBH), 20.8% of patients with liver cirrhosis and 16.8% of patients with hepatocellular carcinoma with no serum markers for hepatitis B virus infection. However, the antibody was not detected in sera from patients with acute NANBH. The prevalence of antibody to the protein encoded by the NS1 region was lower than that of antibody to the HCV core protein, but much higher than that of antibody to the envelope protein. Thus, the NS1 region of the HCV genome is suggested to encode a protein produced during the course of HCV replication.

Deficiency of fibrinolytic enzyme activities in the serum of patients with Alzheimer-type dementia

Previously we reported that there is a kallikrein deficiency in the cerebral tissue of patients with Alzheimer-type dementia. The present study was performed to investigate protease changes in the serum of these patients. The results showed that the kallikrein activity was normal, but that the activities of plasmin and urokinase were significantly low. The present findings indicate a derangement in the clotting and fibrinolytic systems in Alzheimer patients.

[Investigation of glutathione-S-transferase isozymes in human lenses]

Glutathione-S-Transferase (GST) isozymes in human lenses were investigated by the immunoenzymatic method using antibody against human liver GST2 and GST3 after polyacrylamide gel isoelectric focusing (western blotting method). Also, rocket immunoelectrophoresis was carried out for the detection of GST1. It was found that GST1 in lens also showed a polymorphism. The GST2 was not found in human clear lenses as well cataractous lenses. In addition, crossreacting materials against both antisera of GST2 and 3 were detected in the pH 6-7 area of the gel in all human lenses.

Dose-dependent enzyme suppression in spleen induced by GM1 (monosialoganglioside 1) administration to mice

Our previous studies suggested that the administration of exogenous gangliosides to the body modulates enzymatic networks in the brain. In the present study, we tested whether that is the case with another organ, spleen. By testing the dose response relationship, we found that there is a optimum dose for the effect of enzymatic modulation of GM1 (monosialoganglioside 1) administration. Although the optimum level varied depending on each of the examined hydrolytic enzymes, it usually fell in the range around 50 micrograms/kg body weight. The findings led us to conclude that the enzyme-modulating actions of gangliosides come not merely from the bizarre actions in vivo of high molecular exogenous substances.

Effects of OPC-21268, an orally effective vasopressin V1 receptor antagonist in humans

An orally effective, nonpeptide vasopressin V1 receptor antagonist, OPC-21268 was produced for possible human use. We investigated the effects of OPC-21268 on the vascular effects of intra-arterially infused arginine vasopressin in human forearm vessels. The brachial artery was cannulated for drug infusions and direct measurement of arterial pressure. Forearm blood flow was measured by a strain gauge plethysmograph, and forearm vascular resistance was calculated. Arginine vasopressin was infused intra-arterially at doses of 0.02, 0.06, 0.09, 0.2, 0.6, and 1.2 ng/kg/min. The lower doses of arginine vasopressin increased, whereas the higher doses of arginine vasopressin decreased forearm vascular resistance (p less than 0.01). Intra-arterial infusion of phenylephrine at doses of 0.2, 0.4, and 2.4 micrograms/min increased forearm vascular resistance dose-dependently (p less than 0.01). OPC-21268 (50 mg for two, 100 mg for six, and 200 mg for two subjects) given orally did not alter resting arterial pressure, forearm vascular resistance, or heart rate. OPC-21268 decreased vasoconstrictor responses to arginine vasopressin at doses of 0.02 (p less than 0.02) and 0.09 (p less than 0.05) ng/kg/min and augmented vasodilator responses to arginine vasopressin at a dose of 1.2 ng/kg/min (p less than 0.01). However, the vasoconstrictor responses to phenylephrine were not altered by OPC-21268. These results demonstrated that OPC-21268 effectively and specifically antagonized the V1 receptor-mediated vasoconstriction in human forearm resistance vessels. These results suggest that OPC-21268 may be useful therapeutically to antagonize the vasoconstriction caused by arginine vasopressin in some pathological states.