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Biomedical subjects

A Hayashi

Publications and source records attributed to A Hayashi.

At least 451 records · Page 25Linked to original sources
PubMed1980

Effect of infused L-threo-3,4-dihydroxyphenylserine on adrenergic activity in patients with familial amyloid polyneuropathy.

L-threo-3,4-dihydroxyphenylserine (DOPS), an immediate precursor amino acid of (-)-norepinephrine, was used as a pharmacological tool to investigate the pathophysiology of the peripheral sympathetic nervous system in Type 1 familial amyloid polyneuropathy. Patients with the well-established disorder showed an enhanced pressor response to L-threo-DOPS under conditions that produced no change in normal subjects. While octopamine induced a brisk pressor response, L-threo-DOPS produced a slow and prolonged change in blood pressure, with a marked concomitant increase in urinary excretion of norepinephrine. A slight increase in urinary excretion of total metanephrine was observed in both groups, but there was no significant increase in serum dopamine-beta-hydroxylase activity. Since infusion of dilute norepinephrine into patients also produced a markedly hypersensitive response, the characteristic pressor response to L-threo-DOPS was indicative of denervation supersensitivity of adrenergic receptors to norepinephrine formed enzymatically from L-threo-DOPS.

Adult↗
PubMed1980

Enhanced purification of Mullerian inhibiting substance by lectin affinity chromatography.

Mullerian inhibiting substance (MIS), a secreted testicular product responsible for regression of the Mullerian ducts in the male mammalian embryo, was purified 7000 fold, exploiting the glycoprotein nature of this important fetal regressor to achieve enhanced purification. The present procedure employs media incubation of newborn calf testis, passage through DEAE Bio-Gel A and CM Bio-Gel A and sequential lectin affinity chromatography on wheat germ lectin (WGL)-Sepharose 6MB and concanavalin A (Con A)-Sepharose 4B. Strongly bioactive MIS was released from both lectin columns in the bound glycoprotein fraction only after elution with lectin-specific sugar. Carbohydrate analysis of the highly purified glycoprotein fraction eluted from Con A indicated the presence of both N-acetyl glucosamine and mannose, as would be expected from its sequential lectin affinity, as well as of galactose, galactosamine and N-acetyl neuraminic acid. Electrophoresis of this fraction on polyacrylamide-SDS gels showed an identical band pattern after staining with either Coomassie blue or periodic acid-Schiff reagent, further indicating that MIS is a glycoprotein.

Animals↗
PubMed1980

A quantitative study of acetylcholine in Hirschsprung's disease.

This is the first report on acetylcholine (Ach) quanititaion of the aganglionic colon by a chemical assay. Ach content in the colon of Hirschsprung's disease was measured by pyrolysis gas chromatography, which was found to be a simple, accurate, and reliable method. Microwave irradiation on the surgical resected specimens was performed before extraction procedure to abolish acetylcholinesterase (Ach-E) and cholineacetyltransferase (CAT) activity in the tissue. Ach content in the ganglionic colon was 8.51 +/- 3.15 nmole/g (n 5 in contrast to 23.79 +/- 14.17 nmole/g (n = 19) in the aganglionic segment of Hirschsprung's disease. The meaning of elevated Ach level in the aganglionic segment was discussed from the pathophysiologic standpoint.

Acetylcholine↗
PubMed1980

Further studies on the functional properties of hemoglobin M Hyde Park.

The oxygen binding properties of Hb M Hyde Park (92 beta, histidine leads to tyrosine) were reinvestigated directing special care to testing the wave length-dependence of the oxygen equilibrium curve and to stabilizing hemoglobin samples using a methemoglobin reductase system. There was no indication that the Hb M Hyde Park fraction separated on a DEAE Sephadex column contained an unknown hemoglobin derivative which appeared in earlier studies. Contrary to earlier observations, there was no significant wave length-dependence of the equilibrium curve of Hb M Hyde Park, verifying the spectrophotometric determination of oxygen saturation. The reductase system satisfactorily reduced the normal alpha chain met hemes without reducing the abnormal beta chain met hemes. The oxygen binding property of Hb M Hyde Park is characterized by 3 to 4 times higher oxygen affinity than that for normal hemoglobin, complete loss of cooperativity, and substantially preserved Bohr effect. These results are consistent in part but not entirely with those observed by earlier investigators. The oxygen affinity of Hb M Hyde Park is between the affinity of the oxy structure and the deoxy structure of normal hemoglobin. Oxygen equilibrium curve of red cell suspension and whole hemolysate containing Hb M Hyde Park were biphasic, indicating that Hb M Hyde Park also exhibited the high oxygen affinity in those samples.

Cytochrome-B(5) Reductase↗
PubMed1979

Müllerian duct regression in the embryo correlated with cytotoxic activity against human ovarian cancer.

A significant cytotoxicity index was obtained when human ovarian cancer cells in a microcytotoxicity assay were exposed during the S (DNA-synthesizing) phase of the cell cycle to purified fractions of testis exhibiting high Müllerian inhibiting substance bioactivity. The same effect was not observed when these fractions were tested against human glioblastoma or fibroblast lines. Most human ovarian cancers are said to resemble Müllerian tissues histologically. Müllerian inhibiting substance may thus deserve further study as a potential chemotherapeutic agent.

Animals↗
PubMed1979

Influences of temperature change on the relaxation and amplitude inhibition by noradrenaline in the rabbit jejunum.

In the rabbit jejunum, the elevation of temperature within the range of 25-37 degrees C diminished the sensitivity to noradrenaline (NA) for both the relaxation and amplitude inhibition. The relaxation by NA was mainly mediated via adrenergic beta-receptors at 25, 30 or 37 degrees C. The amplitude inhibition was mediated via alpha-receptors at 37 degrees C, and both alpha- and beta-receptors at 30 or 25 degrees C.

Animals↗
PubMed1979

Catecholamine metabolism in familial amyloid polyneuropathy.

In order to evaluate the involvement of the peripheral autonomic nervous system in the pathogenesis of type 1 familial amyloid polyneuropathy, the urinary excretion rates of catecholamines and serum dopamine-beta-hydroxylase (DB/) activity were examined in 22 patients at various clinical stages. Changes in both indices were closely linked to the progression of the illness; urinary excretion rates of catecholamines were first decreased in patients suffering from moderate autonomic dysfunction, while serum DBH activity was significantly reduced only in patients with far advanced disease. These findings suggested that patients with advanced disease might be suffering from a chronic deficiency of catecholamines in the peripheral sympathetic nerves. Administration of L-dopa, however, failed to improve the clinical manifestations.

Adult↗
PubMed1979

Application of an automatic oxygenation technique to analysis of oxygen equilibrium curves for hemoglobinopathic red cells and functional screening of clinically important hemoglobinopathies.

The automatic oxygenation technique of Imai et al (Biochimica Biophysica Acta, 200:189--196, 1970) was slightly modified and applied to the study of oxygen equilibrium curves of dilute, red-cell suspensions from normal subjects and individuals with hemoglobinopathies, enzymopathies, and other hematologic disorders. The p50 values of non-smoking, normal adults were 25.9 +/- 0.6 mm Hg at pH 7.4 and 37 degrees C, and corresponded to the values for whole blood reported in the literature. The oxygen equilibrium curves of suspensions from subjects with enzymopathies revealed shifts in position which are thought to be due to alterations in the concentration of 2,3-DPG of the red cells. Abnormalities in shape of the equilibrium curves were observed only for the hemoglobinopathic red cells, and could best be illustrated by the abnormally low Hill's exponent (n*). Analyses of the n* values of 34 patients with various red-cell disorders of unknown causes led to the identification of ten cases showing low values. In five of the ten patients, the presence of an abnormal hemoglobin was confirmed using column chromatography on Amberlite CG--50. These results point to the usefulness of the Hill Plot analysis of red-cell oxygen dissociation curves in functional screening for clinically important hemoglobinopathies.

Erythrocytes↗
PubMed1979

Levels of resistance to six synthetic insecticides in the Borneo housefly.

The resistant levels of the 4 strains of the housefly collected in Borneo to six insecticides, namely DDT, Chrysron, DDVP, Baytex, Sumithion and Diazinon, were examined. It was found that most housefly population in Borneo showed a higher susceptibility than that of the Takatsuki strain of Japan, especially to DDT.

Animals↗