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Biomedical subjects

N Yasuda

Publications and source records attributed to N Yasuda.

At least 289 records · Page 16Linked to original sources
PubMed1984

A possible explanation for effects of Sr2+ on contraction-relaxation cycle in canine stomach.

Effects of Sr2+ on smooth muscle activity and Ca2+ movement by plasma membrane (PM) were examined in preparations isolated from canine stomach to determine how Sr2+ modulates the contraction-relaxation cycle in smooth muscle. Sr2+ caused contraction in Ca2+-free solution. In the presence of Sr2+, KCl caused a response similar to that in normal Ringer's solution, this contraction was inhibited by both nitroprusside and verapamil. Sr2+ inhibited Ca2+ uptake by PM in the presence and absence of ATP. Release of Ca2+ from loaded PM vesicles was accelerated by Sr2+. Results suggest that Sr2+ could replace Ca2+ in Ca2+ binding sites in the cell.

Adenosine Triphosphate↗
PubMed1984

The gene frequency of SB alleles in the Japanese population.

The gene frequency (+/- SD) of SB alleles was estimated in the Japanese population as follows: SB1 0.00, SB2 0.195 +/- 0.027, SB3 0.070 +/- 0.017, SB4 0.091 +/- 0.019, SB5 0.335 +/- 0.034 and SB blank 0.308 +/- 0.035. The absence of SB1 allele, decrease of SB4 allele and increase of SB5 allele are characteristic features of the SB system in the Japanese population as compared with Caucasians.

Alleles↗
PubMed1984

Geographical variations in inborn errors of metabolism in Japan.

Using materials from a nationwide screening project on inborn errors of metabolism in Japan, the incidence of histidinemia, phenylketonuria, galactosemia and homocystinuria were found to be 140, 16, 14 and 7 in 1 million live births, respectively. Geographical variations were observed, especially in histidinemia, which are most likely due to chance.

Amino Acid Metabolism, Inborn Errors↗
PubMed1984

A surveillance system for metabolic disorders in Japan.

Statistical procedures based on a Poisson hypothesis for surveying serial occurrences of incidence were developed. Three methods, the z-test, the cusum technique and the sequential test were applied in a study of a nationwide screening system on newborns for hereditary metabolic disorders in Japan. It was found that the statistical tests well detected human errors involved in data processing.

Humans↗
PubMed1984

In vivo and in vitro comparisons of biological activities of bovine, ovine and rat CRF (corticotrophin-releasing factor).

The biological activity of partially purified bovine hypothalamic CRF (corticotrophin- releasing factor) was compared to those of synthetic CRFs (ovine, rat) sauvagine and vasopressin in vivo and in vitro. ACTH-primed hypophysectomized rats with heterotopically transplanted pituitaries and medial basal hypothalamic ablation (H-T + MBHA ), and intact rats pre-treated with chlorpromazine, morphine and Nembutal (C-M-N) were used for in vivo CRF assays. Perifused rat adenohypophyseal fragments were employed for in vitro studies. CRF-A (void volume fractions, 'big' CRF) and CRF-B (Kav = 0.583) purified from bovine hypophyseal stalk, synthetic ovine and rat CRF, and sauvagine all induced significant stimulation of ACTH and/or corticosterone secretion in these systems. Synthetic ovine and rat CRF and sauvagine showed comparable CRF potency. The CRF dose-response slopes for bovine CRF were somewhat steeper than those for ovine CRF or sauvagine in the in vitro system. Vasopressin had the least steep dose-response slope. Intravenous bolus administration of ovine CRF caused a more prolonged (greater than 20 min) elevation of plasma ACTH compared to a relatively short duration after bovine CRF-A. These data suggest that bovine hypothalamus contains substance(s) which exhibits different CRF characteristics from those of ovine CRF.

Adrenocorticotropic Hormone↗
PubMed1984

Heterogeneity of activity of the prolactin-releasing factor in the bovine hypothalamo-neurohypophysial complex.

Fresh samples of bovine hypothalamic median eminence or hypophysial stalk extracted with 0.1 M-HCl and fractionated on Sephadex G-100 had two prolactin-releasing factor (PRF) components, the major one in the void volume (PRF-A) and the minor one in an elution position (partition coefficient (Kav) = 0.333) immediately after PRF-A (PRF-B). Similar fractionation of bovine posterior pituitary extracts showed two PRF peaks: PRF-A and another in a more retarded position than PRF-B (Kav = 0.645; PRF-C). Storage of bovine stalk extract at -20 degrees C for 1 year caused a shift from higher molecular weight PRF into PRF-C. Thyrotrophin-releasing hormone stimulated prolactin secretion, but its dose-response slope and chromatographic mobility were quite different from those for bovine tissue extracts. Secretion of prolactin induced by extracts of bovine hypophysial stalk is calcium dependent and is inhibited by dopamine.

Animals↗
PubMed1984

J chain synthesis and ultrastructural changes in chronic lymphocytic leukaemia cells during in vitro differentiation.

The synthesis of J chain and the ultrastructural changes in chronic lymphocytic leukaemia (CLL) cells during in vitro cultures stimulated with PWM and/or allogenic T cells were investigated by immunoelectron microscopy, radioimmunoassay and anti-idiotype antibodies, in an attempt to demonstrate changes in the maturation stage of CLL cells. The cells from four patients showed the induction of J chain synthesis in parallel with the increase of Ig synthesis. Two of revealed cytological transformations, in which CLL cells resembled immunoblasts or plasmacytoid cells. These findings suggest that some CLL cells are not 'frozen' within the original maturation stage and can be induced to differentiate to a more mature stage.

Cell Differentiation↗
PubMed1983

Synthesis and antibacterial activity of triazole and isoxazole derivatives of ampicillin.

In order to improve the antibacterial activity of ampicillin, new penicillin derivatives having a 1-aryltriazole-4-carboxamide group or a 5-arylisoxazole-3-carboxamide group at the alpha-position of benzylpenicillin or p-hydroxybenzylpenicillin were synthesized. Some compounds in these series were found to possess high activity against Pseudomonas and other Gram-negative bacteria. In addition, structure-activity relationships, especially the effect of the hydrophobic character of the compounds on activity, were investigated.

Ampicillin↗