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Biomedical subjects

A Watanabe

Publications and source records attributed to A Watanabe.

At least 829 records · Page 46Linked to original sources
PubMed1986

Ammonia detoxification by accelerated oxidation of branched chain amino acids in brains of acute hepatic failure rats.

BCAA aminotransferase and BCKA dehydrogenase activities are increased in the mitochondrial fractions from the brains of hepatic failure rats treated with two-thirds removal of CCl4-injured liver. Cerebral leucine decarboxylation was accelerated, and it well correlated with arterial blood ammonia levels. Elevation of brain ammonia content following an intraperitoneal injection of ammonium acetate to hepatic failure rats could be prevented by intravenous infusion of BCAA. Significantly increased brain glutamic acid, glutamine, and alanine contents were noted. These results suggested that accelerated brain BCAA catabolism in acute hepatic failure rats reduce the neurotoxicity of ammonia by promoting the synthesis of glutamic acid and glutamine from BCAA.

Acute Disease↗
PubMed1986

Prevention of ammonia-induced brain edema in dogs infused with a branched-chain amino acid solution.

Infusion of an ammonium acetate solution into dogs during mannitol-induced reversible opening of the blood-brain barrier resulted in a marked rise in intracranial pressure (ICP). The preventive effect of a branched-chain amino acid (BCAA) solution on ammonia-induced brain edema was tested by measuring ICP and brain water content. The BCAA solution apparently prevented ammonia-induced brain edema, indicating that BCAA accelerated ammonia detoxification in the brain.

Acetates↗
PubMed1986

A new phosphate bonded investment.

A new type of phosphate bonded investment has been studied. The setting expansion was found to be 0.03-0.05%, the thermal expansion was 1.54-1.85% depending upon the mixing liquid used: water or aqueous glycerol solutions, 5, 10, or 20%. Trial castings of alloys with a thermal expansion room to solidus temperature ranging from 1.60 to 1.91% showed either a very high accuracy or the possibility of improving the accuracy actually found by modifying the glycerol content of the mixing liquid used. To prevent cracking, heating of the investment mould in the temperature range 200-300 degrees C must be slow, probably not faster than 2-3 degrees per min.

Chemical Phenomena↗
PubMed1986

Cephalothin and penicillin G polymers as elicitors of rat PCA mediated by mouse IgE antibodies.

PCA-eliciting activities of cephalothin- and penicillin G-polymers were examined in rats sensitized with homologous IgE antibodies of mouse origin. Cephalothin-polymers elicited PCA regardless of the source of antibodies and the methods to raise them, the minimal effective dose being 2 to 20 micrograms/animal. Penicillin G-polymers provoked PCA only when anti-benzylpenicilloyl IgE antibody of C57BL/6J mouse raised early after immunization was used. The minimal effective dose in this case was 5 micrograms/animal, being comparable to that of cephalothin polymers.

Animals↗
PubMed1986

Heterogeneity of cross-reactivity of mouse anti-benzylpenicilloyl antibodies against cephalothin haptens or polymers.

The cross-reactivity of mouse anti-benzylpenicilloyl antibodies against cephalothin-haptens and cephalothin-polymers was divergent depending on the source and isotype of antibodies and the methods to raise them. High cross-reactivity nearly equal to the reactivity to homologous haptens and polymers was obtained only with the IgE antibody of C57BL/6J mouse raised shortly after an immunizing injection of the emulsion containing Freund's complete adjuvant and benzylpenicilloyl-bovine gamma-globulin conjugate. With the other antibody preparations, cross-reactivity was moderate to negligible.

Animals↗
PubMed1986

Detection of type V collagen-degrading enzyme activity in human liver.

Type V collagen-degrading enzyme activity was detected as a metalloprotease acting at neutral pH in the human liver. Type V collagen extracted from human placenta and labeled with [1-14C] acetic anhydride was used as the substrate in the assay. Four major degradation products with relatively high molecular weights were observed upon polyacrylamide gel electrophoresis of the incubation mixture of type V collagen and liver homogenate. The significance of the measurement of this enzyme activity was discussed in relation to the clarification of the mechanism of liver fibrosis.

Collagen↗
PubMed1986

Assay procedures for cathepsin B, H and L activities in rat tissue homogenates.

Cathepsin B, H and L activities in small amounts of rat tissue homogenates corresponding to 10 micrograms protein were determined with 7-amino-4-methyl-coumarin conjugates as substrates. A new procedure for serum cathepsin H activity was also developed. High cathepsin B and H activities were found in kidney, spleen and liver. Liver cathepsin B, H and L activities in D-galactosamine-injured rats were decreased concomitantly with an increase in serum cathepsin H activity.

Animals↗
PubMed1986

Mechanical, thermal, and optical changes of the nerve membrane associated with excitation.

Nerve fibers produce several non-electrical signals on excitation. Recent findings on such non-electrical signals are discussed, in the hope that some of them might give us clues to molecular events underlying the excitation process. At present this expectation is not fulfilled, but progress is being made which allows one to look optimistically at future developments.

Absorption↗
PubMed1986

Impending catheter perforation of superior vena cava: radiographic recognition.

In six of nine patients with superior vena caval perforation by a central venous catheter, the chest radiograph showed a gentle curve at the tip of the catheter 4 hr to 7 days before clinical or radiographic recognition of perforation. This radiographic sign should prompt catheter repositioning to avoid the morbidity and potential mortality associated with superior vena caval perforation.

Catheterization↗
PubMed1986

Plasma level of branched chain alpha-amino acids following its alpha-keto acid administration to rats.

To detect the effective substance accelerating the conversion of branched chain alpha-keto acids (BCKA) to corresponding amino acids, some sugars, sugar alcohols, ethanol, octanoate and ATP were tested with intravenous injection of three BCKA to rats. Plasma leucine levels 30 min after BCKA injection in rats, which were infused with 2 M solution of fructose or sorbitol, reached the significantly high peak corresponding to 860% and 790% of the basal levels. Administration of ethanol (2 or 3.5 M) or octanoate (4.5 mM) also resulted in significantly high levels of leucine in plasma following BCKA injection as compared with control. Molar ratio of plasma branched chain amino acid (BCAA)/aromatic amino acid 30 min after BCKA injection increased to 12.9 in control rats. The ratios 60 and 120 min after BCKA administration were significantly higher in rats treated with ethanol (3.5 M) or octanoate (4.5 mM) than those in control. These results suggest that infusion of the metabolites inducing high NADH/NAD ratio in their metabolic pathways results in inhibition of BCKA decarboxylation and, as a result, enhancement of transamination of BCKA into BCAA.

Adenosine Triphosphate↗
PubMed1986

[A study of the antineoplastic activity of K18].

K18 is a new drug produced by a combination of Melphalan and human immunoglobulin. K18 produced an inhibitory effect on the proliferation of human gastric and colon cancer transplanted in to nude mice. Also, combination effects of K18 with MMC and 5-FU were recognized in the same system. In a study of distribution after K18 administration, the accumulation and retention of this drug in the tumor region were observed. In the case of Melphalan administration, these phenomena were not observed. The antitumor activity of tumor homogenate was evaluated using a colony-forming assay with KB cells. As to the Melphalan-treated group, a four-hour homogenate reduced the number of colonies but a 48-h one did not. In the K18-treated group, the four-hour homogenate decreased the number slightly and the decrease became obvious with 48-h homogenate. In cell cycle analysis using K18 or Melphalan administration, gathering of S-phase cells was observed, but these changes appeared later with K18 than with Melphalan. This result showed that the effect of K18 was produced by the alkylating activity of Melphalan which was combined with immunoglobulin. For clinical application, K18 was administered to cancer patients at a dose of 60-90 mg every day. Two cases of good response were achieved. No side effect was observed. This remarkable efficacy and low degree of side effects in clinical application is probably due to the higher affinity and accumulation of K18 in the tumor region. K18 is a useful new drug for clinical application alone, or in combination with other chemotherapeutic drugs.

Animals↗
PubMed1986

Diagnosis, treatment and prognosis of small hepatocellular carcinoma.

Diagnosis, treatment and prognosis of hepatocellular carcinoma (HCC) of small size, not larger than 5 cm in diameter, were studied in forty-three patients with underlying cirrhosis, who were detected among one-hundred-and-sixty-five HCC cases over a period of 4.5 years from 1981 to 1985. The patients included fifteen cases with tumors smaller than 3 cm in diameter which were diagnosed HCC mostly during the follow-up period of liver cirrhosis. Among various imaging procedures, real-time linear scan ultrasonography (US) had a 91% positive HCC detection rate, hepatic angiography 93% and computed tomography (CT) 88%. Surgical treatment including partial resection, subsegmentectomy and segmentectomy, was carried out in fifteen HCC cases with well-compensated cirrhosis. Transcatheter arterial embolization (TAE) was performed in nineteen cases with severe liver dysfunction and multiple location of tumors. Three-year survival was 80% in twelve patients with hepatic resection (performed since 1981) and 19% in the TAE cases; none of the other cases survived.

Adult↗