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Biomedical subjects

Y Toyoda

Publications and source records attributed to Y Toyoda.

At least 271 records · Page 15Linked to original sources
PubMed1985

Catabolite inactivation of fructose 1,6-bisphosphatase and cytoplasmic malate dehydrogenase in yeast.

Catabolite inactivation of fructose 1,6-bisphosphatase and cytoplasmic malate dehydrogenase was studied using the protease-deficient and vacuole-defective yeast strain pep4-3. The catabolite inactivation of fructose 1,6-bisphosphatase in pep4-3 was found to have a normal first inactivation step but with a defective second proteolytic step. In contrast, catabolite inactivation of cytoplasmic malate dehydrogenase was normal in pep4-3. These results suggest that the proteolytic pathways utilized in the hydrolysis of the two enzymes may be different and that proteolysis of fructose 1,6-bisphosphatase may require functional vacuoles while proteolysis of cytoplasmic malate dehydrogenase may not.

Cytoplasm↗
PubMed1985

Abnormalities in gangliosides and other lipids of monkey, rabbit and human brains with chronic organic mercury intoxication.

The distribution patterns of gangliosides and other major lipids in the monkey, rabbit and human brains with chronic organic mercury intoxication were examined. Various areas of the monkey brains were tested for alterations in the lipid composition in detail. Phosphatidylethanolamine and phosphatidylcholine slightly decreased, and sphingomyelin increased in all the areas tested of the intoxicated brains. The total ganglioside concentration was elevated in the frontal and basal ganglia gray matter tissues. In the percentage distribution of gangliosides, GD1b, GT1b and GQ1b (B pathway, [19, 20]) increased, while GM2, GM1 and GD1a (A pathway, [19, 20]) decreased. Similar ganglioside pattern changes were observed also in a human brain and in a rabbit brain with chronic organic mercury intoxication. The altered distribution patterns of gangliosides may be attributable to the proliferation of reactive astrocytes due to organic mercury.

Animals↗
PubMed1985

Compositional changes in brain lipids, especially cerebroside and gangliosides, of rats treated with methylmercury chloride.

Rats were orally given 4 mg of methylmercury chloride per kg per day up to 14 days, and killed at 4-day or arbitrary intervals. Parietal gray matter and cerebellum were taken for lipid analyses. The ganglioside content increased during the early stage before the manifestation of clinical symptoms. After the onset of clinical signs, the total lipid concentration was elevated, and especially the levels of phosphatidylethanolamine and cerebroside were increased. The ganglioside distribution patterns were also altered in the late stage, showing decreased proportion of GD1a and increased percentages of GD1b and GQ1b.

Animals↗
PubMed1984

Purification and phosphorylation of fructose-1,6-bisphosphatase from Kluyveromyces fragilis.

Fructose-1,6-bisphosphatase from the yeast Kluyveromyces fragilis was found to have an apparent Mr = 155,000 and to be composed of four Mr = 35,000 subunits. The extent and rate of phosphorylation of fructose-1,6-bisphosphatase (Fru-1,6-P2) by yeast cAMP-dependent protein kinase were dependent on fructose-1,6-bisphosphatase inhibitors, 5'-AMP and fructose 2,6-bisphosphate (Fru-2,6-P2). In the absence of inhibitor, the enzyme was slowly phosphorylated with a maximum incorporation of 1 mol of phosphate/mol of enzyme. The presence of both inhibitors greatly increased the phosphorylation rate with a maximum incorporation of 2 mol of phosphate/mol of enzyme. The presence of only one inhibitor led to an intermediate rate of phosphorylation with 2 mol of phosphate incorporated/mol of enzyme. There was no significant change in enzymatic activity after phosphorylation. The estimated sedimentation coefficient of fructose-1,6-bisphosphatase was lowered by 5'-AMP from 8.2 to 5.7 while Fru-2,6-P2 increased the S value to 8.5. The presence of either Fru-1,6-P2 or Fru-2,6-P2 prevented the 5'-AMP lowering of S value. The susceptibility of enzyme to partial tryptic digestion was not changed by the presence of 5'-AMP. The presence of both Fru-2,6-P2 and 5'-AMP led to the protection of Mr = 35,000 subunit from tryptic digestion while Fru-2,6-P2 alone led to a protection of an Mr = 30,000 peptide fragment. This peptide fragment did not contain the phosphorylation sites. Our results suggest that the rapid regulation of fructose-1,6-bisphosphatase following glucose addition is controlled mainly by enzyme inhibitors.

Ascomycota↗
PubMed1984

Device for determining location of an endotracheal catheter tip.

The location of a catheter's tip in the bronchi may be determined using a stethoscope and an audible sound that has a frequency of 558 Hz and a sound pressure of 136 dB for the adult. The device is easy and safe to use, and has been used in a broad range of patients for over 4 yr without sequelae.

Auscultation↗
PubMed1984

Affinity of mutarotase for Sephadex and glycogen.

It was found that hog kidney mutarotase has an affinity for Sephadex G-100, equilibrated and eluted with 5 mmol/l EDTA buffer (pH 7.4), resulting in retardation of its elution from the column. The affinity was reduced depending upon the presence of 0.15 mol/l NaCl and 0.2 mol/l glucose, separately or in combination. A small portion of mutarotase was adsorbed to rabbit liver glycogen as judged from the column chromatography of a mixture of the two on Bio-Gel P-100. Mutarotase was adsorbed to neither dextran nor raw potato starch.

Animals↗
PubMed1984

Alterations in brain gangliosides and other lipids of patients with Creutzfeldt-Jakob disease and subacute sclerosing panencephalitis (SSPE).

Lipid composition was examined with cerebral cortices of three cases of Creutzfeldt-Jakob (C-J) disease and one case of subacute sclerosing panencephalitis (SSPE). Phosphatidylethanolamine decreased in both C-J and SSPE brains. Sphingomyelin increased in CJ. The levels of cholesterol esters which occurred in a trace amount in normal control were elevated in C-J and more severely in SSPE. The total amounts of gangliosides were reduced in C-J and SSPE. Gangliosides GD1b, GT1b and GQ1b in the biosynthetic pathway B [23] specifically decreased in C-J, while GM1 and GD3 increased. An increased content of GD3 may be related to the proliferation of reactive astrocytes. A decrease of 22:6 (n-3) accompanied with an increase of oleic acid in the fatty acid composition of the acidic phospholipid fraction was observed. This might be a cause for alterations in membrane function.

Adult↗