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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 1,243 records · Page 69Linked to original sources
PubMed1977

Effect of supplementation of methionine and threonine to a protein free diet on urinary excretion of nitrogen and tissue free amino acids in rats.

It was previously reported that methionine and threonine supplementation to a protein free diet had a greater nitrogen sparing effect than methionine supplementation along. The reduced urinary nitrogen excretion by methionine and threonine is due to the reduced excretion of urea. In the present study, the changes in tissue level of free amino acids and ammonia were investigated. Ornithine is one of the urea cycle inter-mediates and may play an important role for urea formation, therefore the liver concentration of ornithine was also determined. The contents of ammonia in plasma were the same in these two groups and the ammonia content in liver of rats fed the control diet was smaller than that of rats fed the protein free diet supplemented with methionine and threonine. The contents of some amino acids in tissues were significantly reduced. The concentrations of aspartic acid, glutamic acid, alanine and serine in plasma and liver of rats fed the protein free diet supplemented with methionine and threonine were, particularly, significantly reduced as compared with those of rats fed the protein free diet. In addition to the decrease of free amino acids which are considered to be nonspecific nitrogen carriers from the peripheral tissues, the concentration of ornithine in liver was also significantly reduced. The results suggest that the decreased migration of free amino acids from peripheral tissues to the decreased level of liver ornithine would efficiently reduce the urea formation in rats fed the protein free diet supplemented with methionine and threonine.

Amino Acids↗
PubMed1977

Hemoglobin E and glucose-6-phosphate deficiency in the Khmer Air Force (Cambodia).

This study was designed to investigate the use of primaquine in malaria control in the Khmer Republic (Cambodia). Blood was drawn from 106 male Khmer Air Force troops for analysis of hemoglobin E and glucose-6-phosphate (G-6-PD) deficiency. A test group of 15 men with G-6-PD deficiency and a group of 31 normal controls were given 15 mg of primaquine each morning for 14 days. The patients were followed for hemoglobinuria and changes in hematocrit. Primaquine induced a significant, but not a dangerous, hemolysis in G-6pD-deficient Khmer troops. The G-6-PD deficiency seen in Khmer Air Force subjects was G-6-PD Mahidol. Statistically, G-6-PD Mahidol was linked to hemoglobin E.

Cambodia↗
PubMed1977

Studies on uremic toxins: the identification and the determination of toxic effect by tissue culture method.

Uremic serum fractions obtained by Amicon XM-10 hollow fiber and membrane filtration was investigated using cytotoxicity in tissue culture by Rose's circumfusion system and by monolayer culture. The cytotoxic fraction was investigated with Elphor-Va 4, IR spectrometry, mass spectrometry, and NMR spectrometry for analysis of the true form of the substance. Remarkable cytotoxicity was observed in the small molecular fraction. Of the substances which may be surmised as uremic toxins, such as urea methylguanidine (MG), guanidinosuccinic acid, etc., only MG presented a similar cytotoxicity to this fraction. From the result of mass spectrometry, infrared spectrometry, and NMR spectrometry, it appeard that the electropositive substance included in the small molecular fraction was intimately associated with MG or one of its derivatives. The middle molecular fraction showed an inhibitory effect on cultured mouse liver glucokinase and human erythrocytic Na-K-dependent ATPase.

Adenosine Triphosphatases↗
PubMed1977

Hepatocarcinogenic effects of N-nitroso-N-methylurea in guinea pigs.

Intragastric administration of N-nitroso-N-methylurea to strain 13 male guinea pigs, at a weekly dosage of 7.5 mg/kg for 15 weeks and then twice weekly for a subsequent 15 weeks, induced high toxicity, as evidenced by weight loss and mortality and a high incidence of malignant neoplasms, over a total observational period of 40 weeks. The neoplasms included hepatic angiosarcomas, cholangiocarcinomas, and generalized lymphoblastic lymphomas.

Adenoma, Bile Duct↗
PubMed1977

Molecular abnormality of PI S variant of human alpha1-antitrypsin.

Alpha1-antitrypsin variant protein was purified to homogeneity from a PI S-S subject with a mild deficiency of plasma trypsin inhibiting capacity. Molecular weight, specific trypsin inhibitory activity, and composition of amino acids and carbohydrates were similar to the proteins purified from Pi M-M individuals with normal alpha1-antitrypsin activity. The structural difference between the normal and the variant alpha1-antitrypsin was elucidated by peptide mapping of their tryptic digests. An amino acid substitution of glutamic acid in the normal protein to valine in the variant protein was found. The result is consistent with the previously reported amino acid substitution in Pi S-Christchurch.

Amino Acid Sequence↗
PubMed1977

Temperature-dependence of tension development by glycerinated muscle fibers of rabbit psoas in Mg-ITP solution.

The isometric tension of single fibers isolated from glycerinated rabbit psoas muscle was measured at various temperatures using Mg-ITP as a substrate. The tension developed in Mg-ITP decreased linearly as the temperature was reduced from 24 degrees C to 4 degrees C. Myosin formed the myosin--product complex predominantly via ATP hydrolysis at the burst site during Mg-ATP hydrolysis, irrespective of temperature, and the tension developed in Mg-ATP decreased linearly as the temperature decreased (Yoshida and Tawada (1976) J. Biochem. 80, 861). During Mg-ITP hydrolysis, myosin forms the myosin*-product complex predominantly at the burst site above 20 degrees C, while myosin forms the myosin*-substrate complex below 8 degrees C (Hozumi (1976) Eur. J. Biochem. 63, 241). However, the temperature dependence of tension development in Mg-ITP is linear, as with Mg-ATP, as mentioned above. This temperature dependence is not compatible with some muscle models which assume the formation of the myosin*-product complex by cross-bridges prior to combination with actin during contraction.

Animals↗
PubMed1977

Problems of indirect immunologic assay of specific enzyme activity.

The estimation of specific activity of variant enzymes is important for understanding the mechanism of inherited enzyme deficiency. Direct determination of specific enzyme activity is often difficult. Indirect immunologic methods, i.e., the quantitative neutralization method and the electroimmunoassay method using specific antiserum, have been used for estimating the specific activity of variant enzymes. The validity of these indirect methods was examined with the use of normal and variant human glucose 6-phosphate dehydrogenase (G6PD), and three different anti-G6PD sera. The specific activities of purified normal, partially denatured normal, partially purified normal, and partially purified preparations of four different G6PD variants were estimated by the indirect methods. The values estimated by the neutralization method and that obtained by the electroimmunoassay method were substantially different, and different antisera gave different values for the given G6PD preparations. The values estimated by the indirect methods do not reconcile with the specific enzyme activity determined by the direct determination. Therefore, care should be taken in deducing the specific enzyme activity from the immunologic assay.

Enzyme Activation↗
PubMed1977

G6PD Ube, a glucose-6-phosphate dehydrogenase variant found in four unrelated Japanese families.

A total of 6,120 Japanese males were screened for glucose-6-phosphate dehydrogenase deficiency (G6PD). Five cases with the deficiency were discovered. Two of them and an additional two cases have the same variant, G6PD Ube, characterized by moderate enzyme deficiency, fast moving enzyme activity on electrophoresis, high Ki Nadph, utilization of substrate analogues, kinetics, pH optima, and stability. This variant was distinguished for G6PD A- and from other Oriental variants by biochemical parameters. Differences in the frequency and type of the variants between southern Asia and Japan, suggest that the Japanese who have been isolated on islands where malaria is not endemic, may have developed their own variant traits.

Adult↗
PubMed1977

Metabolism of benzo(a)pyrene by guinea pig pancreatic microsomes.

The in vitro microsomal metabolism of the strain 13 guinea pig pancreas was investigated by determining the benzo(a)pyrene (BP) hydroxylase activity in the 9000 x g supernatant and microsomal pellet. BP hydroxylase activity in both 9000 x g supernatant and microsomal pellet of the pancreas was less than 1% of the activity in the respective liver fractions, However, pretreatment of animals with methylcholanthrene or BP at 20 mg/kg, for either 1 day or 3 consecutive days, markedly enhanced the BP hydroxylase activity of pancreatic microsomes over that of controls; the induction in the liver microsomes was less than 2-fold over that of controls. The hydroxylation of BP by pancreatic microsomes was linear with time over a 30-min period, with the rate of hydroxylation dependent on both the enzyme and substrate concentrations.

Animals↗
PubMed1977

The fate of 14C-elastin in the peritoneal cavity of rats. I. Biochemical studies.

Degradation of elastin was studied in rats after intraperitoneal implantation of a suspension of 14C-elastin that had been prepared by labeling bovine elastin with 14C-formaldehyde. Most of the degradation of 14C-elastin, measured by releasing the radioactivity in urine and feces, occurred between 6 and 15 days after the implantation. During this period an increase of leukocytes and macrophages in the implanted site was observed. This followed a brief increase in neutrophils. Furthermore, an elevation of the elastolytic activity, measured by the 14C-elastin, was found in cell lysates of both macrophages and neutrophils, which were recovered by lavage of the peritoneal cavity. But the enzymatic activity was not found in the cell-free lavage. On the contrary, there was elastase inhibitor in the lavage, increased by the implantation. The mechanism of the elastin degradation in the peritoneal cavity was discussed.

Animals↗
PubMed1977

A glucose 6-phosphate dehydrogenase Gd (-) Castilla variant characterized by mild deficiency associated with drug-induced hemolytic anemia.

Erythrocyte G-6-PD deficiency is an X-chromosome-linked hereditary trait which is common in many ethnic groups. A deficiency of G-6-PD in red cells is often associated with hemolytic anemia. This report defines a new variant designated as Gd (-) Castilla, which is associated with drug-induced hemolysis. The red cell G-6-PD activity of the variant subject is about 20% of normal. The variant enzyme is thermolabile in vitro and it has faster than normal anodal electrophoretic mobility and normal substrate affinity. The hemolytic problem of the subject might be correlated to sensitivity to NADPH inhibition and molecular instability of the variant enzyme.

Adult↗
PubMed1976

G6PD Lozere and Trinacria-like. Segregation of two non hemolytic variants in a French family.

Two new G6PD variants have been found in red blood cells of the members of a French family originating from Lozere. The father is hemizygous for an electrophoretically fast variant with mild enzyme deficiency (50--60% of normal). The abnormal paternal G6PD gene is segregating in his daughter who is double heterozygous for maternal and paternal variants. This mutant enzyme, different from previously described variants is designated as Gd Lozere. The mother is heterozygous for another G6PD variant. Two sons are hemizygous for this latter mutant enzyme characterized by a moderate deficiency (25--30% of normal) and slower electrophoretic mobility with some slightly altered kinetic properties. This G6PD had been identified as Gd Trinacria like. These two abnormal enzymes are not associated with any hemolytic problem. Case reported is the first showing the segregation of two new mutant enzymes, distinct from common G6PD variants, among the members of the same family.

Electrophoresis, Starch Gel↗