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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 1,459 records · Page 81Linked to original sources
PubMed1987

Fluorometric high-performance liquid chromatography of N-acetyl- and N-glycolylneuraminic acids and its application to their microdetermination in human and animal sera, glycoproteins, and glycolipids.

A simple, rapid, and highly sensitive high-performance liquid chromatographic method is described for the determination of N-acetyl- and N-glycolylneuraminic acids in human and animal sera, glycoproteins, and glycolipids. The neuraminic acids, released by acid hydrolysis of these biological samples, are converted in dilute sulfuric acid with 1,2-diamino-4,5-methylene-dioxybenzene, a fluorogenic reagent for alpha-keto acids, to highly fluorescent derivatives. The derivatives are separated within 12 min on a reversed-phase column (Radial-Pak cartridge C18) with an isocratic elution and detected fluorometrically. The detection limits are 25 fmol (7.7 pg) for N-acetylneuraminic acid and 23 fmol (7.5 pg) for N-glycolylneuraminic acid in a 10-microliter injection volume at a signal-to-noise ratio of 2. This method permits precise determination of the neuraminic acids in 5 microliter of human and animal sera or in 0.25-2.5 micrograms of glycoproteins and glycolipids.

Animals↗
PubMed1987

Reduction of suppressor cell activities of human peripheral blood lymphocytes by a streptococcal preparation, OK-432.

The effect of a streptococcal preparation, OK-432 on suppressor cell activities of peripheral blood lymphocytes was investigated. Suppressor cell activities were significantly reduced when they were generated in vitro by concanavalin A (Con A) in the presence of OK-432. However, the reduction of suppressor cell activities was not observed when OK-432 was added in the effector phase. Similarly, a significant reduction of prostaglandin E2 (PGE2)-induced suppressor cell activities by OK-432 was observed. No increases of either T-cells with Fc receptors for IgG or OKT8 reactive T-cells were observed after Con A stimulation in the presence of OK-432. The suppressive effect of the soluble suppressor factors (SSF) was not abrogated by OK-432 and the release of SSF from cells activated by Con A was not found in the presence of OK-432. Thus, it is suggested that OK-432 might interfere with the induction of suppressor cells, but not with the expression of their activities.

Biological Products↗
PubMed1987

Prostaglandin production by human myometrium, uterine cervix and leiomyoma.

In order to investigate prostacyclin production by human myometrium, uterine cervix and leiomyoma, slices of each tissue were incubated. The 6-keto prostaglandin F1 alpha concentration of the incubation medium was measured by radioimmunoassay. The serosal and endometrial sides of myometrium produce 6-keto prostaglandin F1 alpha, with no significant difference in production between the two sides. The 6-keto PGF1 alpha production of leiomyoma was significantly higher than that of myometrium. Our results suggest that human myometrium and leiomyoma produce prostacyclin regardless of vascularization.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Histologic characteristics of gonadotropin-producing hepatoblastoma: a survey of seven cases from Japan.

Histologic studies of the human chorionic gonadotropin (hCG) producing hepatoblastoma were made for seven cases encountered in Japan. It was found in all cases that multinucleated tumor giant cells in several figures were admixed in usual hepatoblastoma tissue and one of them was confirmed to be hCG positive immunohistochemically. Round and clear cells adjacent to or separate from the giant cells showed squamoid metaplasia with occasional pearl formation. These histologic elements were highly suspected to be derivatives of choriocarcinoma and were ascertained to be characteristic of the hCG-producing hepatoblastomas. Only one among seven cases survived long after hepatic lobectomy. At the time of recurrence, none showed elevation of serum or urinary hCG level, while serum alpha-fetoprotein (AFP) level became high again. That was because recurrent tumors contained none of the characteristic elements that had been found in preceding tumors.

Carcinoma, Hepatocellular↗
PubMed1987

Calcitonin and hepatic fatty acid synthesis: effect of thyroparathyroidectomy on the elevation of ATP citrate lyase activity by refeeding of starved rats.

The effect of thyroparathyroidectomy (TPTX) on ATP citrate lyase regulation, a rate-limiting enzyme of fatty acid synthesis in hepatic cytosol, was investigated in rats refed after a 24 h fast. ATP citrate lyase activity in the hepatic cytosol was increased 2-fold by refeeding. This increase was suppressed about 50% by TPTX. The suppression of the enzyme activity by TPTX was completely restored by administration of calcitonin (CT; 80 MRC mU/100 g body weight). This hormonal effect was also observed at 20 MRC mU/100 g dose of CT. CT administration to refeeding-TPTX rats produced a significant increase in the calcium content of the liver tissue and the cytosol. The cytosolic ATP citrate lyase activity increase with CT administration was completely blocked by treatment of cytosol with EGTA (10 microM). This inhibition was clearly reversed by addition of calcium ion (1.25-5.0 microM). In addition, CT-induced rise in enzyme activity was markedly reduced by the presence of W-7 (5 and 50 microM), a calmodulin inhibitor, in the enzyme assay system. The present results suggest that CT plays a role in the elevation of hepatic ATP citrate lyase activity brought about by refeeding of fasted rats, and that this hormonal regulation might depend on Ca2+-calmodulin.

ATP Citrate (pro-S)-Lyase↗
PubMed1987

Murine DNA polymerase beta gene: mapping of transcription initiation sites and the nucleotide sequence of the putative promoter region.

The nucleotide sequence of the region (total, 2,512 base pairs [bp]) from intron 2 to the 5'-flanking region was determined for the mouse DNA polymerase beta genomic clone, and the 300-bp region from intron 1 to the 5'-flanking region was also sequenced for the rat clone. At 51 bp upstream from the ATG codon which was previously suggested to be the translation initiation codon for the rat cDNA sequence, we found another ATG in the same reading frame in both mouse and rat genes. Three major transcription initiation sites (cap sites) each for rat and mouse DNA polymerase beta mRNAs were localized precisely by primer extension analysis at 51, 41, and 0 bp upstream from the first ATG codon, suggesting that this codon is used for translation initiation. The 400-bp region around exon 1 was extremely G + C rich (about 70%). Although neither a TATA box nor a CAAT box was found within the 500-bp region upstream of the 5'-most cap site, triple repeats of 5'-CCGCCC were found within the 100-bp region flanking the cap site.

Amino Acid Sequence↗
PubMed1987

Visualization of surface antigens on yeast protoplasts by gold or ferritin markers.

Surface antigens of Saccharomyces cerevisiae protoplast were visualized immunocytochemically with protein A-gold or ferritin conjugated antibodies. Ferritin particles were densely distributed at the surface of yeast protoplast after treatment with rabbit anti-protoplast serum and ferritin conjugated antibody against rabbit IgM. Control experiments demonstrated that the binding of these ferritin markers was specific for surface antigens. The composition of these surface antigens, however, remain to be investigated.

Antigens, Fungal↗
PubMed1987

Study on left atrial contractile performance--participation of Frank-Starling mechanism.

We estimated the magnitude of the left atrial contraction in 28 patients with ischemic heart disease by calculating the biplane cineangiographic volumes of the left atrium. The left atrial contraction contribution to the left ventricular stroke volume (ml/m2, Y axis) correlated inversely with the left ventricular ejection fraction (%, X axis), yielding an equation: Y = -0.31X + 43.7 (n = 28, r = -0.56, p less than 0.001). The result indicates that the left ventricular filling is compensated by the augmented atrial contraction in case of impaired left ventricular function. We defined the left atrial volume at the beginning of the atrial contraction (LAVd, ml/m2) as the "preload" of the left atrium, and we also defined the volume expelled by the active atrial contraction (delta LAVa, ml/m2) as the stroke volume of the left atrium. The stroke volume (Y) correlated positively with the "preload" (X), yielding an equation: Y = 0.48X - 1.3 (n = 28, r = 0.80, p less than 0.001). We then defined the left ventricular end-diastolic pressure, the peak of the a-wave, as the "afterload" of the left atrium, and we studied the "afterload"-stroke volume relations in the left atrium. However as expected, a reasonable relationship between them was difficult to form. Consequently, we showed that an increase in the "preload" of the left atrium augmented the stroke volume of the left atrium, which means that Frank-Starling mechanism is operative in the left atrium.

Adult↗
PubMed1987

Pressure-volume relationships in the pulmonary "venous" system in living dogs.

In this study, we examined the pressure-volume (P-V) relationships of the pulmonary "venous" (P'V') system in anesthetized living dogs, and assessed compliance by fitting the derived data of the P-V relationships to the exponential function. By definition, the P'V' system consists of the pulmonary veins and the left atrium. The pulmonary "venous" volume (P'V'V) was determined with our modified double indicator dilution method using a single injection and double sampling technique. The mean left atrial pressure (PLA) was measured directly. To observe sequential changes over a wide range of the P-V relationships, dogs were studied from the control state through the volume-loaded state with dextran. The P'V'V ranged from 3.4 to 12.2 ml X kg-1 and the PLA from 3.2 to 40.6 mmHg. We fitted the data of the P-V relationships (n = 24) to the exponential function, yielding an equation: P'V'V (ml X kg-1) = 19(1-0.833(e-0.017PLA(mmHg)). We then differentiated an above equation to estimate the slope of this curve (static compliance), giving the equation: dV/dP (ml X mmHg-1 X kg-1) = 0.269(e-0.017PLA(mmHg)). Therefore, at PLA of 10 mmHg (normal level), the compliance is 0.227 ml X mmHg-1 X kg-1. The compliance, obtained with an application of the present results in dogs to man, (disregarding expected species differences), coincides well with that in man determined with our indirect method.

Animals↗
PubMed1987

Effect of shiitake (Lentinus edodes) and maitake (Grifola frondosa) mushrooms on blood pressure and plasma lipids of spontaneously hypertensive rats.

To study the effect of Shiitake (Lentinus edodes) and Maitake (Grifola frondosa) on hypertension, spontaneously hypertensive rats (SHR) were fed a diet containing 5% mushroom powder and 0.5% NaCl solution as drinking water for 9 weeks. The dietary mushrooms decreased the blood pressure. The plasma free cholesterol level decreased in Shiitake-fed animals, whereas in Maitake-fed animals the total cholesterol level decreased. There was no difference in the plasma triglyceride and phospholipid levels among the experimental groups. Shiitake feeding resulted in a decrease in VLDL- and HDL-cholesterol whereas Maitake feeding caused a decrease in VLDL-cholesterol only. Plasma LDL-cholesterol was not affected by dietary mushrooms. The results suggest that dietary mushrooms prevent blood pressure increase in hypertension.

Animals↗