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Biomedical subjects

M Miyoshi

Publications and source records attributed to M Miyoshi.

At least 163 records · Page 9Linked to original sources
PubMed1977

Transient appearance of a provocative growth hormone response to L-dopa following incomplete adenomectomy in an acromegalic patient.

A 33-year female patient with active acromegaly and hyperthyroidism was examined before and after incomplete removal of a pituitary adenoma. Before adenomectomy the mean basal plasma GH level was 786+/-189 ng/ml. After surgery this value decreased to 251+/-22 ng/ml. Before surgery L-dopa decreased the plasma GH levels, but after adenomectomy normal GH responses were transiently observed to L-dopa. At 10 months after incomplete surgery the GH response to L-dopa became abnormal again despite a lower GH concentration. These findings suggest that the abnormal GH response to L-dopa may be due to a short-loop negative feedback system which was reset by an elevated GH level.

Acromegaly↗
PubMed1977

Influence of synthetic thyrotropin-releasing hormone tartrate monohydrate on plasma gonadotropin concentration of normal males.

Synthetic thyrotropin-releasing hormone (TRH) tartrate monohydrate was administered by rapid intravenous injection to nine normal males. Plasma thyroid-stimulating hormone (TSH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured before and at selected periods after TRH injection. The mean plasma TSH value immediately prior to TRH injection was 3.5 muU/ml and the level 15 min after injection was 14.8 muU/ml. The mean plasma LH value immediately prior to TRH injection was 8.0 mIU/ml and the level 15 min after injection was 15.0 mIU/ml. The latter elevation was statistically significant (p less than 0.01), although it was just above the upper normal range. The mean plasma FSH value immediately prior to TRH injecion was 7.7 mIU/ml, and a significant difference was not observed after TRH administration. These results revealed that synthetic TRH tartrate monohydrate influenced the release of LH from the anterior pituitary.

Adult↗
PubMed1977

The isolation and characterization of a lethal protein from Kintoki beans (Phaseolus vulgaris).

A lethal protein with hemagglutinating activity but without trypsin inhibitory activity was isolated from beans of Phaseolus vulgaris, cultiva, and Kintoki and proved homogeneous by ultracentrifugation, disc polyacrylamide gel electrophoresis, sodium dodesyl sulfate polyacrylamide gel electrophoresis and isoelectric focusing. The molecular weight was estimated to be 104, 000 by ultracentrifugal analysis and gel filtration on Sephadex G-200. The molecule dissociates into three identical subunits in the presence of 8 M urea or 0.1% sodium dodesyl sulfate. The amino acid composition was characterized by the high content of aspartic acid and the complete absence of methionine and cystine. The carbohydrate content was 8.1%; 5.0% mannose and 3.1% glucosamine. The addition of the lethal protein to a basal diet (0.4%) resulted in the intensive depression of the growth and finally in the death of rats. The intraperitoneal injection of 250 microgram per g body weight of mouse brought about an acute toxicity which caused death of all the injected mice.

Amino Acids↗
PubMed1976

[Plasma prolactin and thyroid-stimulating-hormone (TSH) in patients with breast cancer (author's transl)].

In order to investigate plasma prolactin and thyroid-stimulating-hormone (TSH) concentration and pituitary reserve of these two hormones in patients with breast cancer, following examinations were carried out. Plasma prolactin concentration was measured before and 15, 30, 60, 90 minutes after the 500mug of thyrotropin-releasing-hormone (TRH) i.v. injection in 22 patients with breast cancer and 4 patients with benign breast disease. All patients did not take any hormonal therapy and any medication inducing prolactin secretion. Ten healthy females were also tested as controls. Plasma prolactin concentration was estimated by a double antibody radioimmunoassay (RIA) technique using hPRL RIA kit provided by NIAMDD. The basal prolactin concentration in patients with breast cancer was 18.6 +/- ng/ml (Mean +/- SEM), and it was slightly higher than the control group (14.7 +/- 2.2 ng/ml), but not statistically significant. In 6 out of 22 patients with breast cancer, high plasma prolactin concentrations more than 25 ng/ml were observed. The maximal plasma prolactin concentration following the TRH injection was obtained at 15-30 minutes after TRH in most patients with breast cancer. The maximal value was 87.4 +/- 9.2 ng/ml, and it was near the upper limit of normal range of prolactin response, and not significantly higher than the maximal value in the control group (59.7 +/- 5.7 ng/ml). In 7 patients with breast cancer, the maximal prolactin values more than 100 ng/ml were obtained after TRH injection. There was no statistically significant difference between early breast cancer group (TNM: stage I & II, N=14) and advanced breast cancer group (TNM: stage III & IV, N=6) in both the plasma prolactin concentration and the pituitary prolactin reserve...

Adult↗
PubMed1976

Purification and partial characterization of a protein proteinanse inhibitor isolated from eggplant exocarp.

A protein proteinase inhibitor was isolated and purified from eggplant exocarp by heat treatment, ammomium sulfate fractionation, column chromatography on DEAE-cellulose, and gel filtration on Sephadex G-25 and G-50. The final purified preparation of the inhibitor was found homogeneous by electrophoretic analysis. The inhibitor showed strong and stoichiometric inhibition on trypsin whereas it showed weak inhibition on alpha-chymotrypsin. It displayed no inhibiting characteristics on pepsin. The molecular weight of the inhibitor was estimated to be approximately 6000. This finding, with the trypsin inhibition data, suggested that the inhibitor combined trypsin in the molar ratio of 1:1. The amino acid analysis indicated that the inhibitor is rich in half-cystine, glycine and aspartic acid, and contains no tryptophan, histidine, methionine or valine.

Amino Acids↗
PubMed1976

Synthesis of elastin. A rapid formation of lysine-derived crosslinks by chick embryo aorta.

Aortas of 13-day-old chick embryo were labeled for 0.5 hr with [14C]lysine and subjected to a serial extraction after chase for 1-24 hr with [12C]lysine. Substantial radioactivity was found in insoluble elastin after 3 hr chase. The effect of beta-amino-propionitrile on labeling with [14C]lysine was also examined. Each fraction was hydrolyzed and applied to a short column on an amino acid analyzer. Radioactivity was found in desmosine and isodesmosine of insoluble elastin as early as 1 hr after the beginning of chase. The radioactivity increased rapidly at 2 hr and very slowly thereafter. A large count, which was separated into five peaks on a long column, was observed in other lysine derivatives at 2 hr and increased steadily up to 24 hr, while the lysine count decreased from 1 : 0.5 to 1 : 6 against lysine derivatives and from 1 : 0.04 to 1 : 0.9 against quarter-desmosine after 24 hr. The oxidation of lysine residues incorporated during the 0.5 hr pulse was almost completed during the first 1 hr of chase, and these oxidized residues were incorporated into crosslinks during the following 1 hr. It is suggested that poorly crosslinked elastin accumulated in the soluble fractions. The presence of crosslinking derived from lysine residues was also indicated in the microfibril fraction.

Amino Acids↗
PubMed1975

Conformational and spectral analysis of the polypeptide antibiotic N-methylleucine gramicidin S dihydrochloride by nuclear magnetic resonance.

The 220-MHz proton magnetic resonance spectrum of the cyclic decapeptide antibiotic, mono-N-methylleucine gramicidin S, is reported and all the resonances have been assigned to specific protons of the constituent amino acids. Three methods--temperature dependence and solvent mixture (methanol-trifluoroethanol and dimethyl sulfoxide-trifluoroethanol) dependence of peptide NH proton chemical shifts and proton deuteron exchange--habe been utilized to delineate peptide NH protons. The results of the above methods, coupled with the observed vicinal alpha-CH-NH coupling constants and chemical shifts, indicate that in trifluoroethanol the peptide NH PROTONS OF D-Phe4, D-Phe9, L-Orn2, and L-Val6 are exposed to the sovent, and those of L-Val1, L-Orn7, and L-Leu8 are solvent shielded and intramolecularly hydrogen bonded. In trifluoroethanol, dimethyl sulfoxide, and methanol, the decapeptide has no C2 symmetry, and there are only minor conformational differences in the different solvents. In the proposed conformation in trifluoroethanol, one-half of the decapeptide retained the hydrogen bonding pattern of gramicidin S, i.e. cyclo-(L-Val1 NH--O-C L-Leu8) (a beta turn) and cyclo-(L-Leu8 NH--O-C L-Val1). The second half of the molecule exhibits a different type of stable beta turn involving the ten-atom hydrogen-bonded ring, cyclo-(L-Orn7-NH--O-C D-PHE4).

Computers↗
PubMed1975

[Studies on hypophyseo-thyroid function in patients with chronic thyroiditis (author's transl)].

It is well known that serum TSH levels are elevated in most patients with chronic thyroiditis, even if the patient exhibits normal thyroid function tests. The determination of serum TSH levels in these patients is thought to be the most sensitive indicator of subclinical hypothyroidism. In this study, the hypophyseo-thyroid functions of untreated euthyroid patients with chronic thyroiditis were evaluated. Serum T3 levels in most of these patients were raised or at high normal levels, although serum T4 levels were in the low normal range. Serum T4 levels in patients with raised basal TSH were distributed in the low normal range. Hence, it is suggested that the decreased serum T4 stimulates TSH secretion which in turn stimulates T3 (and T4) secretion from the thyroid and the elevated T3 maintains the patient's euthyroid condition. Basal TSH levels in these patients varied from 2.5 to 37.0 muU/ml and mean +/-SD was 12.9+/-9.6 muU/ml. Thirteen out of 30 patients (43%) with normal free T4 indices showed elevated basal TSH levels. TSH responses to TRH injection were exaggerated in all euthyroid patients with raised basal TSH levels, as well as in 11 out 14 patients (78.6%) with normal basal TSH levels as well. But the maximum TSH responses after TRH injection were well correlated with basal TSH levels (gamma=0.79). The percent increases of serum T3 after TRH injection in those patients were less than those of the normal person, and there was no difference in T3 response between the normal TSH group and the group with raised TSH. Eight patients who suffered from collagen diseases (SLE:6, RA:1, PSS:1) without any evidence of thyroid disease also exhibited exaggerated TSH responses to TRH. In five out of these eight patients (62.5%) antithyroglobulin antibody was positive. This may indicate the presence of the so-called asymptomatic autoimmune thyroiditis in these patients. It is suggested that the elevated basal TSH levels in euthyroid patients with chronic thyroiditis are a much more sensitive indicator of thyroid failure than any other routine thyroid function tests. Moreover, the exaggerated TSH responses to TRH in patients with normal basal TSH levels indicated that the TRH-test is more useful for the detection of minimal thyroid failure, especially in patients having such conditions as asymptomatic automimune thyroiditis.

Collagen Diseases↗
PubMed1975

Inhibition of intestinal absorption of phenylalanine by phenylalaninol.

Plasma phenylalanine and tyrosine levels in rats which had been orally administered L-phenylalaninol and L-phenylalanine were determined. Since these amino acid levels in rats administered L-phenylalanine solution containing L-phenylalaninol were significantly lower than those in rats administered L-phenylalanine alone. L-phenylalaninol appears to inhibit the intestinal absorption of L-phenylalanine. This effect was more potent than that of cycloleucine. L-phenylalaninol inhibited the phenylalanine transport of everted sacs. The Km value of L-phenylalanine was 3.44 X 10(-3) M and the Ki value of L-phenylalaninol was 7.69 M 10(-3) M from Lineweaver-Burk plots. From these two curves, it appeared that L-phenylalaninol may competitively inhibit the intestinal transport of L-phenylalanine. The effects of L-phenylalanine, L-phenylalaninol and cycloleucine on the urinary excretions of Na+ and K+ in rats were also examined. Potassium excretion which increased on oral administration of L-phenylalanine, was suppressed by the administration of L-phenylalaninol but not administration of cycloleucine. L-phenylalaninol alone enhanced Na+ excretion in urine. These results confirmed that L-phenylalaninol shows inhibitory effects as potent as those of cycloleucine on the intestinal absorption of L-phenylalanine.

Animals↗
PubMed1975

Occurrence of a trypsin inhibitor in eggplant exocarps.

A trypsin inhibitor was extracted from eggplant exocarps with several buffers. The 0.1 M acetate buffer, pH 5.5. extract had the highest specific activity. The crude inhibitor, obtained by heat treatment and salting-out from the acetate buffer extract, contained 4.5% nitrogen and 22.6% hexose. Isoelectrofocusing demonstrated that this crude inhibitor in the eggplant exocarps was composed of at least three forms, one of which differed in its isoelectric point. The form at pH 4.7 had the strongest activity. The molecular weights of these inhibitors were estimated to be between 5,000-10,000 by gel filtration.

Chemical Phenomena↗