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Biomedical subjects

S Shinoda

Publications and source records attributed to S Shinoda.

At least 181 records · Page 10Linked to original sources
PubMed1987

Activation of the plasma kallikrein-kinin system by Vibrio vulnificus protease.

Vibrio vulnificus protease enhanced hypodermic vascular permeability when injected into the dorsal skin of a guinea pig. Enhancement of permeability was observed within 2 min, and the permeability-enhancing reaction terminated at about 10 min postinjection. The permeability-enhancing reaction was greatly augmented by simultaneous injection of a kininase II inhibitor, whereas the reaction was inhibited by soybean trypsin inhibitor, a well-known inhibitor of plasma kallikrein. Furthermore, in vitro activation of plasma prekallikrein to kallikrein by V. vulnificus protease was observed. These results indicate that V. vulnificus protease enhances vascular permeability through activation of the plasma kallikrein-kinin system which generates bradykinin, factor in edema formation.

Animals↗
PubMed1987

The effect of short-lasting atrial pacing on the release of atrial natriuretic peptide, vasopressin, and methionine enkephalin in man.

In order to study the effect of atrial tachycardia on the release of atrial natriuretic peptide (ANP), AVP, and methionine enkephalin (M-Enk), plasma concentrations of these peptides in the right ventricle were determined in patients with various arrhythmias (N = 10) during cardiac catheterization and incremental atrial pacing. Each pacing (100 per min, the maximum rate for 1:1 atrioventricular conduction, and 200 per min) lasted 4 to 5 min. Plasma ANP was significantly increased from 53.1 +/- 12.2 in the resting condition to 168.9 +/- 59.9 pmol/l at a pacing rate of 200 beats per min (P less than 0.05); plasma AVP tended to decrease, but not significantly, and plasma M-Enk did not change at all. Pulse pressure in the right atrium (PPRA) and mean right atrial pressure (MRAP) tended to increase during the pacing, and at the rate of 200 beats per min PPRA was significantly higher than at the rate of 100 beats per min. Mean arterial blood pressure, plasma osmolality, and plasma sodium and potassium concentrations did not change significantly. There were significant correlations between plasma ANP and PPRA, MRAP and heart rate. These results indicate that atrial pacing stimulates ANP release with a rise in right atrial pressure, but does not influence M-Enk and AVP releases.

Adult↗
PubMed1987

Effects of Ca2+ and calmodulin antagonists on the Na+ pump activity induced by pilocarpine in dog submandibular gland.

The effects of Ca2+ and calmodulin antagonists on the Na+,K+-ATPase activity were investigated in dog submandibular gland pieces. The Na+,K+-ATPase activity of the gland pieces which were incubated in the presence of 5 microM A23187, a Ca2+ ionophore, was about 2-fold of that seen in the control medium. Verapamil, diltiazem and La3+ (Ca2+ antagonists) and chlorpromazine, trifluoperazine and W-7 (calmodulin antagonists) had no significant effect on the Na+,K+-ATPase activity in the control medium, but significantly inhibited that induced by pilocarpine. These results suggest that the Na+ pump activity is modified by the Ca2+ influx from the extracellular spaces and the intracellular Ca2+-calmodulin complex.

Animals↗
PubMed1987

Does calmodulin participate as an intermediate in the process of glycogenolysis in rat submandibular gland?

A role of calmodulin in the process of the glycogenolysis induced by adrenaline was investigated in rat submandibular gland. When the slice was incubated in the Ca2+-free medium, the adrenaline-induced glycogenolysis was significantly inhibited. Moreover, the inhibition of glycogenolysis induced in the Ca2+-free medium was further enhanced by addition of 2 mM EGTA. Chlorpromazine, trifluoperazine and W-7, calmodulin antagonists, had no effect on the glycogenolysis induced by adrenaline. These results suggest that the adrenaline-induced glycogenolysis is dependent on the presence of Ca2+ and that calmodulin does not participate in the process of glycogenolysis in rat submandibular gland.

Animals↗
PubMed1986

Immunohistochemical study of neuron-specific enolase and CA 19-9 in pancreatic disorders. The value of neuron-specific enolase as a marker for islet cell and nerve tissue.

Immunohistochemical studies of neuron-specific enolase were performed on pancreatic tissues from patients with insulinoma, nonfunctioning islet cell tumor, chronic pancreatitis, and pancreatic adenocarcinoma, and from 5 normal patients. The concentration of neuron-specific enolase was also measured in the sera of patients and in the pancreatic tissue, and the tissues were stained for carbohydrate antigen 19-9 by immunohistochemical techniques. Neuron-specific enolase was localized in nerve fibers, normal islet cells, and islet cell tumors; its concentration was elevated only in the tissue of islet cell tumors and in serum from patients with insulinoma. In the pancreatic tissue of pancreatitis or pancreatic adenocarcinoma, various changes in acini and islets were present. The altered islets stained clearly for neuron-specific enolase and could easily be distinguished from altered, unstained acini in cases of pancreatitis or pancreatic adenocarcinoma. Islets in the pancreatic tissue remained intact with various morphologic changes, although acini had degenerated severely. Carbohydrate antigen 19-9 was localized in all the carcinoma cells in the pancreatic tissue and in some of the normal pancreatic ducts. No cells were simultaneously immunostained by anti-neuron-specific enolase and anti-carbohydrate antigen 19-9 antibodies. Thus, neuron-specific enolase is a good marker for islet cell tumor, and is valuable for examining islets in pancreas with various disorders both alone and in combination with other tumor markers.

Adenocarcinoma↗
PubMed1986

Recessive nonsense suppressors in Saccharomyces cerevisiae: action spectra, complementation groups and map positions.

Three genes SUP111, SUP112 and SUP113 of Saccharomyces cerevisiae have been identified that can mutate to give recessive omnipotent nonsense suppressors. Alleles of these loci can also act as allosuppressors; that is, different phenotypes, due apparently to different efficiencies of suppression, can result from different alleles at a given locus. The SUP111, SUP112 and SUP113 loci map to the right arms of chromosomes VIII, VII and XIII, respectively.

Chromosome Mapping↗
PubMed1986

Evidence for the presence of a novel biosynthetic pathway for norspermidine in Vibrio.

Enzymatic studies of the cell extracts of Vibrio alginolyticus and V. parahaemolyticus provided evidence that there exists a novel biosynthetic pathway for norspermidine (NH2(CH2)3NH(CH2)3NH2), a major polyamine species. In this pathway, the Schiff base formed between aspartic beta-semialdehyde and 1,3-diaminopropane is first reduced by a NADPH-dependent enzyme to yield "carboxynorspermidine" (NH2(CH2)3NH(CH2)2CH(NH2)COOH), which is in turn decarboxylated by a pyridoxal phosphate dependent enzyme to form norspermidine. The end product and its intermediate were identified by gas chromatography - mass spectrometry. Experiments with L-[U-14C]aspartic acid resulted in appreciable incorporation of the label into norspermidine. Putrescine could replace 1,3-diaminopropane as a substrate to produce spermidine, but at a reduced rate. The enzyme activity was greatly enhanced by dithiothreitol. Since the activity of an aminopropyltransferase that utilizes decarboxylated S-adenosylmethionine as an aminopropyl group donor could not be detected in any of the cell extracts by our assay method, it was concluded that this novel pathway is primarily responsible for producing norspermidine and spermidine in these species.

Aspartic Acid↗
PubMed1986

Effect of calmodulin inhibitors on thyroid hormone secretion.

The effect of calmodulin inhibitors, N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7) and trifluoperazine, on TSH-induced thyroid hormone secretion from rat thyroid was examined in vivo and in vitro. The ip administration of 5 mg W-7 to the rat inhibited T4 and T3 secretion from rat thyroids at 2, 3, and 4 h after the ip injection of 2 IU TSH, and so did the ip injection of trifluoperazine at 3 and 4 h. However, the ip injection of N-(6-aminohexyl)-1-naphthalene sulfonamide as a control substance did not show any significant inhibition of T4 and T3 release. To identify the site of action of calmodulin, the effect of W-7 on (Bu)2cAMP-induced thyroid hormone secretion was tested in vitro. One hundred micromolar W-7 completely inhibited T4 release from the rat thyroid when it was enhanced by TSH or (Bu)2cAMP, suggesting that the inhibitory effect of W-7 is subsequent to cAMP formation. These results suggest that calmodulin may play a role in thyroid hormone secretion from the thyroid, acting beyond cAMP formation.

Animals↗
PubMed1986

Enolase subunits in patients with neuroendocrine tumors.

Concentrations of the alpha-, beta-, and gamma-subunits of enolase in surgically resected tumors and serum obtained from patients with various endocrine tumors were measured by a sensitive enzyme immunoassay system. Tissue concentrations of the gamma-subunit were significantly elevated in patients with neuroendocrine tumors concurrent with high concentrations of the gamma-subunit in their serum, which fell to normal in 90% of those who underwent tumor resection. Immunohistochemical analysis revealed that considerable amounts of the gamma-subunit were contained specifically in these tumors. These results indicate that the gamma-subunit of enolase is a useful marker for diagnosing and monitoring patients with neuroendocrine tumors.

Adult↗
PubMed1985

Lateral flagellar antigen of Vibrio alginolyticus and Vibrio harveyi: existence of serovars common to the two species.

The antigenicity of lateral (L-) flagella of two marine vibrios, Vibrio alginolyticus and V. harveyi, was studied, and the two species were found to have common antigenicity of their flagella. Antisera against L-flagella were prepared by immunizing rabbits with highly purified L-flagellar filaments. H-Agglutination tests with the anti-L-flagella antisera showed that four H-serovars existed in these species and that two of them were shared by the two species. Cross reactivity between H-serovars of these two species and other vibrios having lateral flagella, such as V. parahaemolyticus, V. campbellii, V. proteus, or V. fluvialis, was not observed in the H-agglutination test, although partial common antigenicity was observed in the gel diffusion test with flagellin monomers. These observations suggest that surface antigenic determinants of the lateral flagella of V. alginolyticus and V. harveyi are specific to these two species but internal antigenic determinants buried in the flagellar filaments are partially shared with other vibrio species.

Antigens, Bacterial↗
PubMed1985

Some properties of Vibrio vulnificus hemolysin.

Some properties of hemolysin produced by Vibrio vulnificus were investigated. The hemolysin was heat labile, and the hemolytic activity was inhibited by adding cholesterol or divalent cations. Cholesterol inhibited the temperature-independent hemolysin-binding step, suggesting that cholesterol made up the binding site of the cell membrane, whereas the divalent cations inhibited the temperature-dependent membrane-degradation step. However, the V. vulnificus hemolysin was stable to oxygen and sulfhydryl reagents and was not inactivated by antiserum against streptolysin O, suggesting that the V. vulnificus hemolysin differs from oxygen-labile hemolysins which bind to cholesterol. The V. vulnificus hemolysin seems to be one of the exceptional cholesterol-binding hemolysins.

Animals↗
PubMed1985

Respiration-driven Na+ pump and Na+ circulation in Vibrio parahaemolyticus.

Sodium circulation in Vibrio parahaemolyticus was investigated. We observed respiration-driven Na+ extrusion from cells by using a Na+ electrode. The Na+ extrusion was insensitive to a proton conductor, carbonyl cyanide m-chlorophenylhydrazone, and sensitive to a respiratory inhibitor, CN-. These results support the idea of the existence of a respiratory Na+ pump in V. parahaemolyticus. The respiration-driven Na+ extrusion was observed only under alkaline conditions.

Amino Acids↗
PubMed1984

Cytotoxicity and calcium-dependent antigen of Yersinia.

The relationship between invasiveness and calcium dependency was examined in various strains of Yersinia enterocolitica and Y. pseudotuberculosis by using established cell lines. Infection with calcium-dependent bacteria resulted in the formation of microvilli and the adherence of bacteria on the cell surface, and the adherent bacteria were ingested 1.5 hr after infection. Morphological changes in the cells became visible 2 to 3 hr after infection, and intracellular multiplication of the ingested bacteria was noted. When the cells were incubated with bacteria at 37 C for 1.5 hr and then at 25 C, however, the morphological changes in the infected cells were not observed. No isogenic strains that had lost calcium dependency for growth at 37 C were able to elicit the morphological changes in the cells, though they possessed the ability to adhere to and penetrate the cells. The antigen(s) supposedly related to cytotoxicity of the calcium-dependent Yersinia was sought by using antibodies prepared against calcium-dependent bacteria and then absorbed with calcium-independent bacteria and with calcium-independent bacterial cytosol. Double diffusion tests between the antisera and bacterial cytosol extracts revealed the presence of an antigen which was a cytoplasmic substance common to all calcium-dependent but not calcium-independent strains of Y. enterocolitica and Y. pseudotuberculosis.

Animals↗
PubMed1984

Cystathionine accumulation in Saccharomyces cerevisiae.

A cysteine-dependent strain of Saccharomyces cerevisiae and its prototrophic revertants accumulated cystathionine in cells. The cystathionine accumulation was caused by a single mutation having a high incidence of gene conversion. The mutation was designated cys3 and was shown to cause loss of gamma-cystathionase activity. Cysteine dependence of the initial strain was determined by two linked and interacting mutations, cys3 and cys1 . Since cys1 mutations cause a loss of serine acetyltransferase activity, our observation led to the conclusion that S. cerevisiae synthesizes cysteine by sulfhydrylation of serine with hydrogen sulfide and by cleavage of cystathionine which is synthesized from serine and homocysteine.

Cystathionine↗