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Biomedical subjects

T Shiota

Publications and source records attributed to T Shiota.

At least 199 records · Page 11Linked to original sources
PubMed1985

Excitatory and inhibitory amino acid neurotransmitters and ammonia metabolism in hepatic failure rats.

The molar ratio of excitatory amino acid neurotransmitters (glutamate and aspartate) to inhibitory amino acid neurotransmitters (r-aminobutyric acid, GABA, and glycine) in the brain was diminished in acute hepatic failure rats with hyperammonemia, brain edema, and abnormal electroencephalograms. The ratio was further decreased with a marked elevation of arterial and brain ammonia levels 30 min after ammonium acetate was administered i.p. to hepatic failure rats. A continuous infusion of a branched chain amino acid (BCAA) solution before and after the ammonia loading effectively reversed the ammonia-induced lowering of this ratio; high ammonia contents in the brain were concomitantly decreased. Infusing glutamate instead of the BCAA solution failed to produce similar effects probably because of limited entry of glutamate into the brain. The above results suggest that excitatory and inhibitory amino acid neurotransmitter (glutamate, aspartate, and GABA) levels in the brain of hepatic failure rats might vary with abnormal cerebral ammonia metabolism.

Ammonia↗
PubMed1985

Effects of high hepatic acetaldehyde level following simultaneous administration of ethanol and cyanamide on liver function in rats.

Extremely high concentrations of hepatic acetaldehyde were induced in rats by the intragastric administration of ethanol and cyanamide, an aldehyde dehydrogenase inhibitor; and these high levels were maintained for 4 weeks. Liver function tests, including mitochondrial ornithine carbamoyltransferase (OCT) and GOT activities, were within normal limits, and no increase in either hepatic triglyceride or collagen contents was observed. These results suggest that hepatotoxic effects of ethanol are not derived from the high acetaldehyde levels in the liver.

Acetaldehyde↗
PubMed1985

Accumulation of hepatic collagen following long-term administration of sake to rats.

Sake, a rice wine, induced hepatic collagen accumulation in rats. This was noted after 16 weeks of a liquid diet containing 35% ethanol by caloric content. However, under similar experimental conditions, whiskey and ethanol did not produce any changes. Hepatic collagenase activities in sake-fed rats were slightly, but significantly, higher than in the whiskey group. The central and pericellular liver fibrosis in sake-fed rats was caused possibly by either accelerated collagen synthesis or maturation, exceeding the increased collagen degradation. Mechanisms of enhanced fibrogenesis in sake-fed rats were discussed.

Acetaldehyde↗
PubMed1985

Inhibition of plaque and caries formation by a glucan produced by Streptococcus mutans mutant UAB108.

A mutant (UAB108) derived from Streptococcus mutans UAB66, a spectinomycin-resistant (Spcr) isolate of strain 6715, inhibited plaque formation when grown with strain 6715 in a sucrose medium and also inhibited caries formation in gnotobiotic rats infected with both strain UAB108 and 6715. A substance obtained from UAB108 culture supernatant fluid after ethanol precipitation and DEAE-cellulose treatment, designated glucan 108, inhibited S. mutans 6715 virulence and was shown to be a water-soluble glucan. In the presence of sucrose and increasing concentrations of glucan 108, the activity of a glucosyltransferase (GTase) preparation from S. mutans 6715 to synthesize adhesive water-insoluble glucan (ad-WIG) was inhibited, and the activity to synthesize non-ad-WIG was stimulated. Glucan 108 similarly inhibited sucrose-dependent adherence of heat-treated cells, was a poor inducer of cell aggregation, and inhibited S. mutans 6715-induced dental caries in gnotobiotic rats. In the presence of GTase, glucan 108, and sucrose, the glucose moiety of sucrose was found to be incorporated into glucan 108, and most of this glucose-incorporated glucan 108 was found in the non-ad-WIG fraction. The mode of inhibition of plaque formation by S. mutans 6715 appears to involve a shift from ad-WIG to non-ad-WIG formation. The water-soluble glucan 108 was found to have an approximate molecular weight of 2 X 10(6) and was hydrolyzed by fungal dextranase to yield glucans with an average molecular weight of about 1.2 X 10(4). This glucan (designated glucan 12k) was further hydrolyzed by bacterial dextranase to yield smaller glucans and oligosaccharides, but was refractile to alpha (1----3) glucanase. These results suggest that glucan 108 is a branched alpha (1----6) glucan, and it is proposed that UAB108 is defective in its ability to polymerize glucan 12k with alpha (1----3)-linked glucosyl residues.

Adhesiveness↗
PubMed1984

Pleomorphism of hepatic regeneration.

The pleomorphism of hepatic regeneration was studied in acute liver injury and partial hepatectomy of rats. Increases in 3H-thymidine incorporation into the liver DNA fraction and in liver ornithine decarboxylase (ODC) activity were observed similarly in acute liver injury and following a two-thirds partial hepatectomy in normal rats. However, the increase in serum AFP levels was significant only in carbon tetrachloride (CCl4)-treated rats, and the portal-peripheral vein difference in plasma glucagon concentrations was great only in rats that underwent a partial hepatectomy. The weight of the remaining liver increased rapidly following a 67% hepatectomy in normal rats, but not in cirrhotic rats, of which three of five died within 6 days. Increases in liver prostaglandin E levels, 14C-orotate incorporation into the liver RNA fraction and hepatic ODC activity were observed up to 10 h following a partial hepatectomy of normal liver but not after similar removal of cirrhotic liver. Three kinds of hepatic regeneration, i.e., normal and pathologic regeneration following surgical removal of either normal or injured liver and repair of liver damage following chemically induced liver deficiency, were proposed from the observations.

Animals↗
PubMed1984

Characteristic features of plasma amino acid, plasma pancreatic glucagon, serum insulin concentrations in cirrhotic patients with histories of chronic alcohol consumption.

Plasma amino acid, plasma pancreatic glucagon and serum insulin levels were simultaneously measured in cirrhotic patients with (drinkers) and without a history of alcohol drinking (non-drinkers), as compared to those in alcoholics without liver disease. Clinical characteristics in drinkers and non-drinkers, such as the extent of liver dysfunction, which may affect plasma amino acid levels, were strictly matched. Plasma pancreatic glucagon levels in the drinker group were much higher than those in the non-drinker group. In the former group, the elevated plasma pancreatic glucagon levels were correlated (p less than 0.05) to total amino acid levels (the sum of 20 kinds of L-amino acid concentrations) and, elevated AAA concentrations leading to a diminished BCAA/AAA ratio. Drinkers with histories of hepatic encephalopathy presented grossly elevated glucagon levels and severely abnormal aminograms similar to those observed in hepatic insufficiency.

Adult↗
PubMed1984

Serum alpha-fetoprotein in fulminant hepatitis and hepatic regeneration following partial hepatectomy.

The pleomorphism of hepatic regeneration was studied in 10 patients with fulminant hepatitis and 7 with hepatocellular carcinoma, liver cyst, and abscess who underwent partial hepatectomy. Serum AFP levels did not increase significantly following partial hepatectomy. All of four patients who survived fulminant hepatitis had high serum AFP levels with a peak either during or before hepatic encephalopathy. Serum AFP levels decreased rather gradually during the enlargement of the atrophic liver. The observations proposed two kinds of hepatic regeneration, hepatic regeneration following surgical removal of liver and repair of liver damage following virally and probably chemically induced liver deficiency.

Adult↗
PubMed1984

Plasma amino acid imbalance in alcoholic liver cirrhosis.

Plasma amino acid concentrations and plasma glucagon and serum insulin levels were studied in male patients with compensated alcoholic and nonalcoholic liver cirrhosis. Age, nutritional status, and liver function tests were similar in both groups; none of the patients presented hepatic encephalopathy. Plasma valine and leucine concentrations were lower, and tyrosine, higher in alcoholic than nonalcoholic liver cirrhosis. As a result, the molar ratios of branched-chain amino acids (BCAA) to aromatic amino acids (AAA) were reduced markedly in this group. Although correlation coefficients comparing BCAA/AAA ratios and KICG in alcoholic and nonalcoholic liver cirrhosis were similar, a steeper regression line was observed in alcoholics. Plasma glucagon and proline levels were significantly higher in alcoholic than nonalcoholic liver cirrhosis, the former correlated with AAA concentrations only in alcoholic liver cirrhosis, but not with BCAA levels. These results indicated that alcoholic liver cirrhosis presented a more deranged plasma amino acid pattern than nonalcoholic, and the amino acid imbalances, except for depressed BCAA and elevated proline, were derived, in part, from the hyperglucagonemia.

Adult↗
PubMed1984

Glutamic acid and glutamine levels in serum and cerebrospinal fluid in hepatic encephalopathy.

Significant elevation of glutamic acid and glutamine concentrations in CSF was observed in hepatic encephalopathic patients with fulminant hepatitis and liver cirrhosis. However, the ratios of CSF glutamic acid to CSF glutamine levels and of CSF to serum glutamic acid and glutamine levels were significantly higher only in cirrhotic patients with hepatic encephalopathy. CSF glutamine levels were positively correlated with blood ammonia and CSF tyrosine levels in cirrhotic patients. The results indicate that CSF glutamic acid and glutamine levels are important tools in diagnosing hepatic encephalopathy in severe liver disease.

Adult↗
PubMed1984

Hepatocellular carcinoma of small size.

Clinicopathological features of hepatocellular carcinoma (HCC) of small size, not larger than 5.0 cm in diameter, were studied in 11 patients with underlying cirrhosis. The presence of tumor was detected and confirmed by computed tomography (CT) and ultrasonography (US) during periodic imaging re-examinations of cirrhotic patients. The HCCs grew slowly up to a certain stage and formed satellite tumors that could not be visualized on CT image. Therefore, infusion hepatic angiography and/or transcatheter arterial embolization (TAE) are essential before undertaking a major operation.

Aged↗
PubMed1984

Mode of inhibitory action of a bacteriocin produced by Streptococcus mutans C3603.

The basis for the lethal activity of a bacteriocin produced by Streptococcus mutans C3603 (serotype c) was studied. Bacteriocin C3603 was found to adsorb to cells of representative strains of the seven serotypes of S. mutans. S. mutans BHT (serotype b) was used to study the adsorption and the lethal properties of bacteriocin C3603. The adsorption of bacteriocin to cells of S. mutans BHT was inhibited by treatment of cells with protease and beta-glucosidase and by such ligands as poly-L-lysine, poly-L-arginine, L-aspartic acid, L-glutamic acid, glutathione, oxidized glutathione, poly-L-aspartic acid, and poly-L-glutamic acid. The adsorption to cells was also inhibited by oligosaccharides and glucosamine. Mixtures of anionic and cationic amino acids or polyamino acids did not greatly enhance or antagonize the inhibition of adsorption of bacteriocin C3603 to cells. Sodium hydroxide extracts of cell walls and cell wall-membranes contained carbohydrates and proteins; however, only proteins were found to bind to bacteriocin or to a bacteriocin affinity column. The sodium hydroxide extracts contained about 35 protein bands as determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. Bacteriocin C3603 was found to immediately inhibit the synthesis of proteins, DNA, and RNA of cells and to slowly release DNA from cells of S. mutans BHT.

Adsorption↗
PubMed1984

Serological characterization of Streptococcus mutans serotype polysaccharide g and its different molecular weight forms.

The serotype polysaccharide g from Streptococcus mutans 6715 was found to cross-react with serotype polysaccharide a from S. mutans HS6 and serotype polysaccharide d from S. mutans B13. Double immunodiffusion experiments indicated that the serotype polysaccharide g consisted of the following: (i) the type-specific g site; (ii) a cross-reactive site g-a that was in common with polysaccharide a; (iii) a cross-reactive site g-d that was in common with polysaccharide d; and (iv) a cross-reactive site g-(a-d) that was in common with both polysaccharides a and d. Moreover, by a procedure involving several column chromatography steps, six polysaccharide-containing fractions showing reactivity with anti-g serum were found. By gel filtration, the molecular weight estimates of fractions LI, LII, LIII, SI, SII, and SIII were 2 X 10(6), 5 X 10(5), 6 X 10(4), 3 X 10(4), 1.4 X 10(4), and 1 X 10(4), respectively. Double immunodiffusion analysis indicated that LI, LII, and LIII contained the four antigenic sites of the putative polysaccharide g. LII also contained another additional immunodominant region, designated site x. The analysis also suggested that fraction SI lacked the type-specific site g, fraction SII lacked sites g and g-a, and fraction SIII lacked sites g, g-a, and g-d.

Antigens, Bacterial↗
PubMed1984

Two cases of constitutional unconjugated hyperbilirubinemia with marked retention of indocyanine green.

Two cases of chronic unconjugated hyperbilirubinemia and marked retention of indocyanine green (ICG) are described. Since bilirubin uridine diphosphate (UDP)-glucuronyl transferase activities were depressed in their liver, the patients seemed to have bilirubin metabolism similar to that in Gilbert's syndrome. However, the ICG fractional disappearance rates of the cases were rather low (0.018 and 0.019) compared to the rates reported for Gilbert's syndrome. These results suggest that the patients had a new metabolic disorder which results in constitutional unconjugated hyperbilirubinemia and ICG intolerance.

Adult↗
PubMed1984

Quantitative psychometric testing and subclinical hepatic encephalopathy--comparative study between encephalopathic and non-encephalopathic patients with liver cirrhosis.

Six quantitative psychometric tests were performed on 51 healthy subjects, 19 cirrhotic patients with subclinical hepatic encephalopathy (SHE), 32 cirrhotic patients without SHE, and 26 patients with other diseases. Strong correlations between age and the results of all the psychometric tests were observed in the healthy subjects (p less than 0.005). Sex and etiology of liver cirrhosis did not affect the test results. SHE patients, compared with non-SHE and health subjects, presented impairment in the ability to perform the tests, even in the absence of obvious clinical and electroencephalogram findings. In SHE patients, trailmaking test A (TMT A) yielded the highest frequency of abnormal values, 63%. TMT A results were abnormal in 80% of SHE patients with abnormal scores in other tests, and thus it seemed to be the most sensitive test. Liver function tests did not correlate with psychometric testing in any of the groups. Blood ammonia levels in SHE patients with abnormal TMT A scores correlated with TMT A scores (r = 0.752, p less than 0.01); this was not the case in SHE nor non-SHE patients with normal TMT A results. These data demonstrate the usefulness of psychometric tests in detecting SHE.

Adult↗
PubMed1984

Prevention of methionine and ammonia-induced coma by intravenous infusion of a branched chain amino acid solution to rats with liver injury.

The prevention of hepatic encephalopathy by the intravenous infusion of a branched chain amino acid (BCAA)-enriched solution was investigated in methionine and ammonium acetate-treated rats whose liver was already injured with carbon tetrachloride. A BCAA-enriched solution protected the rats from entering a coma. The brain BCAA contents became higher, and the brain methionine and tyrosine levels and the ratio of glutamine to glutamic acid in the brain diminished after administering the BCAA-enriched solution.

Acetates↗
PubMed1984

Accelerated leucine decarboxylation in the rat brain in relation to increased blood ammonia levels during acute hepatic failure.

Leucine decarboxylation in rat brain was investigated during acute hepatic failure, induced by partial hepatectomy after carbon tetrachloride (CCl4) pretreatment of rats. These rats presented metabolic alkalosis, and had significantly higher levels of arterial blood and brain ammonia than control and CCl4-treated rats. Brain leucine decarboxylation was elevated in rats with hepatic failure. This alteration correlated with arterial blood ammonia concentrations, and probably with elevated brain ammonia levels, as brain ammonia levels were directly related to arterial blood ammonia.

Ammonia↗
PubMed1984

Clinical significance of eosinophilia in the diagnosis of halothane-induced liver injury.

Three patients with severe halothane-induced liver injury are described. All patients received halothane anesthesia twice within a short period. High fever and jaundice were noticed soon after the second operation. The prothrombin time was less than 40%, and eosinophilia was greater than 7% prior to these symptoms. Other causes of liver injury were excluded. Diagnostic criteria for halothane-induced liver injury are proposed.

Adult↗