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Biomedical subjects

S Yamaguchi

Publications and source records attributed to S Yamaguchi.

At least 973 records · Page 54Linked to original sources
PubMed1987

[Parathyroid carcinoma: report of a case].

A case of parathyroid carcinoma is presented. A 46-year-old female was admitted to our hospital for fractures of both femurs on July 29, 1983. Laboratory data revealed a serum calcium level of 15.2 mg/dl, serum phosphate level of 1.2 mg/dl, serum immunoreactive parathyroid hormone 9.35 ng/ml (less than 0.5), and % tubular reabsorption of phosphate of 57%. X-ray examination showed marked osteitis fibrosa cystica. The diagnosis of primary hyperparathyroidism was made. A hard tumor was palpable on the left anterior side of her neck. Neck exploration was carried out on August 10. The tumor was found to be localized in contact with the left lower lobe of the thyroid gland. Parathyroid carcinoma was strongly suspected, because the tumor severely adhered to surrounding tissues, thus the tumor was resected en bloc. The histopathological diagnosis was typical parathyroid carcinoma. Postoperative course and the treatment of the fractures were uneventful, and she was discharged able to walk five months after the operation. No evidence of recurrence or metastasis has been seen during the eighteen months since the operation. This is the 80th case in the Japanese literature to our knowledge and the clinical features of these 80 cases revealed an average age of 41.5 years old; male/female ratio of 32/48; average weight of tumor of 8.65 g, palpable neck mass in 72%, bone disease in 64%, and renal disease in 34%.

Carcinoma↗
PubMed1987

White blood cell plugging and blood flow maldistribution in the capillary network of cat cerebral cortex in acute hemorrhagic hypotension: an intravital microscopic study.

The behavior of white blood cells (WBCs) in the capillary network of the cat brain was studied under normal conditions and during acute hemorrhagic hypotension. A small transilluminated area of the cerebral cortex was observed directly, and blood cells flowing through the capillary network were recorded on cinefilm using a high-speed cinecamera. The cell motion was analyzed on the projection screen using a frame-by-frame method. The time during which a single WBC remained at a capillary branching, ie, stagnant time (ST) was examined in detail. In hemorrhagic hypotension, ST was much longer than that in the normal condition. WBC plugging occurred at capillary branchings, and a nonuniform flow pattern (plasma-WBC-accumulated red blood cells [RBCs]) appeared in perfused capillaries. RBC velocity in capillaries was reduced. The ST level was increased significantly with a decrease in RBC velocity. These findings suggest that acute hemorrhagic hypotension may induce flow maldistribution in cerebral microcirculation.

Animals↗
PubMed1986

Renal effects of dichloroacetate in vivo.

We have investigated the effect of dichloroacetate (DCA) on the urinary excretion of lactate and pyruvate in a patient with congenital lactic acidosis and in healthy human controls. DCA administered orally in doses of 50 mg/kg and 30 mg/kg decreased plasma lactate and pyruvate of both the patient and the controls, while the urinary excretion of lactate and pyruvate was increased. However, these urinary increments were too small to contribute to the decrease of plasma lactate and pyruvate.

Acetates↗
PubMed1986

Comparative efficacy of high-dose versus low-dose nicorandil therapy for chronic stable angina pectoris.

Nicorandil therapy was compared with placebo therapy in 11 patients with chronic stable angina pectoris. A computer-assisted treadmill exercise test was performed after administration of either 10 or 30 mg of nicorandil. Analysis of variance showed a significant difference among placebo and nicorandil treatments (p less than 0.01). Ten milligrams of nicorandil prolonged time to onset of ischemia 36% (p less than 0.05) but increased the exercise duration only 15%. Thirty milligrams of nicorandil prolonged time to onset of ischemia 82% (p less than 0.01) and exercise duration 45% (p less than 0.01). Both time to onset of ischemia and exercise duration increased progressively from the 10-mg to the 30-mg dose (p less than 0.05). Heart rate at rest was significantly higher and systolic pressure at rest significantly lower with 30 mg of nicorandil than with placebo. After administration of 30 mg of nicorandil there was a significant reduction in ST depression associated with a slight decrease in the double product at the end of Bruce stage 2 exercise. The peak double product was greater after administration of 30 mg of nicorandil than after placebo, indicating an increased myocardial oxygen supply to the ischemic area. The plasma concentration of nicorandil averaged 78 +/- 83 ng/ml with the 10 mg and 313 +/- 142 ng/ml with 30 mg. There was an increase in exercise duration of more than 1 minute in 8 of 9 patients who had plasma nicorandil concentrations greater than 100 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Brain metabolic correlates of hypoxic-ischemic cerebral necrosis in mid-gestational sheep fetuses: significance of hypotension.

Mid-gestational sheep fetuses exposed to marked hypoxia for 2 h remain brain intact if MABP is maintained above 30 mm Hg. On the other hand, similarly hypoxic fetuses, if they experience reductions in MABP below 30 mm Hg, develop foci of necrosis that predominantly affect hemispheric white matter and neostriatum. Cortex damage is more restricted and is usually associated with more massive underlying white matter damage. The present study examines the brain metabolic basis for the important role of hypotension in brain injury development in marked hypoxia. Sheep fetuses rendered hypoxic by respiring their ewes with 11% oxygen (fetal PaO2 = 8-12 mm Hg) in which MABP was maintained above 30 mm Hg showed increases in brain lactic acid concentrations to 7-13 mumol/g but unaltered energy charge. In contrast, fetuses that sustained MABP reductions below 30 mm Hg showed increases in lactic acid concentrations in vulnerable structures to 16-24 mumol/g accompanied by marked decreases in energy charge. The vulnerable structures also showed reductions in fructose concentrations but a variable behavior of other brain metabolites including phosphocreatine, glycogen, and glucose. Thus, the present findings suggest a relation between hypotension during marked hypoxia, low energy charge, lactic acid accumulation in brain at high concentrations, and fetal brain injury. The ewes of hypoxic hypotensive fetuses received pentobarbital at lower doses than did those of fetuses that maintained blood pressure. This suggests that pentobarbital plays an important role in protecting the fetal brain from asphyxia by extending the hypoxic fetus's ability to maintain blood pressure in addition to reducing its brain metabolism.

Animals↗
PubMed1986

In vitro reconstitution of flagellar filaments onto hooks of filamentless mutants of Salmonella typhimurium by addition of hook-associated proteins.

An in vitro system for reconstituting flagellar filaments onto hooks of filamentless mutants of Salmonella typhimurium was used to investigate the role played in filament formation by the three hook-associated proteins (HAPs, products of the flaW, flaU, and flaV genes). These proteins--FlaW, FlaU, and FlaV--are believed to be assembled in this order at the distal end of the hook. When the recipient hooks were provided by flaU mutants, whose hook tips contained FlaW only, exogenous FlaU was essential for polymerization of both exogenous and endogenous flagellin, whereas exogenous FlaV inhibited such polymerization. When the recipients were flaV-mutant hooks, whose tips contained FlaW and FlaU but not FlaV, exogenous FlaV inhibited polymerization of exogenous flagellin. FlaV also inhibited polymerization of exogenous flagellin at the tips of filament fragments. In contrast, FlaV was essential for polymerization of endogenous flagellin onto flaV-mutant hooks, and onto short filaments that had been made (in the absence of FlaV) by polymerization of exogenous flagellin on the tips of flaV-mutant hooks. These results suggest that FlaV acts not only at the tip of the hook to initiate growth of the filament, but also at the tip of the growing filament, and that FlaV is essential for polymerization of endogenous flagellin--i.e., for the normal process of filament assembly in vivo.

Bacterial Proteins↗
PubMed1986

Subdivision of flagellar genes of Salmonella typhimurium into regions responsible for assembly, rotation, and switching.

Three flagellar genes of Salmonella typhimurium (flaAII.2, flaQ, and flaN) were found to be multifunctional, each being associated with four distinct mutant phenotypes: nonflagellate (Fla-), paralyzed (Mot-), nonchemotactic (Che-) with clockwise motor bias, and nonchemotactic (Che-) with counterclockwise motor bias. The distribution of Fla, Mot, and Che mutational sites within each gene was examined. Fla sites were fairly broadly distributed, whereas Mot and Che sites were more narrowly defined. Local subregions rich in sites of one type were not generally rich in sites of another type. Among Che sites, there was little overlap between those corresponding to a clockwise bias and those corresponding to a counterclockwise bias. Our results suggest that within the corresponding gene products there are specialized subregions for flagellar structure, motor rotation, and control of the sense of rotation.

Alleles↗
PubMed1986

Genetic evidence for a switching and energy-transducing complex in the flagellar motor of Salmonella typhimurium.

The flaAII.2, flaQ, and flaN genes of Salmonella typhimurium are important for assembly, rotation, and counterclockwise-clockwise switching of the flagellar motor. Paralyzed and nonchemotactic mutants were subjected to selection pressure for partial acquisition of motility and chemotaxis, and the suppressor mutations of the resulting pseudorevertants were mapped and isolated. Many of the intergenic suppressor mutations were in one of the other two genes. Others were in genes for cytoplasmic components of the chemotaxis system, notably cheY and cheZ; one of the mutations was found in the cheA gene and one in a motility gene, motB. Suppression among the three fla genes was allele specific, and many of the pseudorevertants were either cold sensitive or heat sensitive. We conclude that the FlaAII.2, FlaQ, and FlaN proteins form a complex which determines the rotational sense, either counterclockwise or clockwise, of the motor and also participates in the conversion of proton energy into mechanical work of rotation. This switch complex is probably mounted to the base of the flagellar basal body and, via binding of the CheY and CheZ proteins, receives sensory information and uses it to control flagellar operation.

Chemotaxis↗
PubMed1986

Abnormal excretion of autofluorescent lipids in urine from patients with neuronal ceroid lipofuscinosis.

Two of our 5 patients with neuronal ceroid lipofuscinosis excreted a large amount of autofluorescent lipids in their urine. These autofluorescent lipids consisted of more than 5 bands in the thin-layer-chromatography. Excitation and emission spectra of these lipids showed that they had heterogeneous components. This finding was specific to neuronal ceroid lipofuscinosis, and never found in other neurological diseases. We also measured unesterified dolichol and dolichol fatty acid ester in urine, and 4 of our patients did not excrete a large amount of such compounds compared with control groups. This finding suggest that increased excretion of dolichol in urine of patient with neuronal ceroid lipofuscinosis may be the secondary effect, but there are some possibilities that certain abnormalities in glycoprotein metabolism exist in neuronal ceroid lipofuscinosis.

Chromatography, Thin Layer↗