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Biomedical subjects

K Kurachi

Publications and source records attributed to K Kurachi.

At least 217 records · Page 12Linked to original sources
PubMed1978

Pituitary LH response to LHRH during puerperium.

Forty puerperal women and 15 normally menstruating women used as controls were given 100 microgram of synthetic luteinizing hormone releasing hormone (LHRH) in a single intravenous injection. Serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and human chorionic gonadotropin (hCG) were measured by a specific radioimmunoassay (RIA). The LH-beta RIA method, which is unaffected by hCG at sample levels as high as 500 IU/ml, was used to determine serum LH levels. Basal serum FSH and LH levels determined immediately after delivery were lower than those in the follicular and luteal phases during the normal menstrual cycle. These levels rose gradually after delivery, and finally returned to normal levels during the 16th to 25th days of the puerperal period. Small, but significant, LH response to LHRH was observed 6-10 days after delivery, and gradually returned to normal thereafter, though the response was poor during the first 35 days of the puerperal period when compared with that of the controls. On the other hand, no FSH response to LHRH was observed until 16-25 days after delivery, when the response was greater than that of the controls.

Adult↗
PubMed1977

Isolation, crystallization, and primary amino acid sequence of human platelet factor 4.

Human platelet factor 4 was purified by a method employing affinity chromatography on heparin/agarose. The amino acid sequence of the protein was determined by automatic Edman degradations and carboxypeptidase Y digestion. There are 70 amino acids in the protein with 5 of the 8 negatively charged residues clustered near the NH2 terminus and 10 of the 13 positively charged residues in clusters of 3 and 4 elsewhere in the protein. Small crystals have been obtained from ammonium sulfate solutions which give a promising preliminary x-ray diffraction pattern.

Amino Acid Sequence↗
PubMed1977

Characterization of bovine factor XIIa (activated Hageman factor).

Factor XIIa (activated Hageman factor) was isolated from bovine plasma by ammonium fractionation followed by heparin-agarose, carboxymethylcellulose, and arginine-agarose column chromatography. It was separated from factor XII in the final step by chromatography on benzamidine-agarose. Factor XIIa has a molecular weight of approximately 74 000 and is composed of a heavy and light chain held together by a disulfide bond(s). The amino-terminal sequence of the heavy chain is Thr-Pro-Pro-Trp--Lys-Gly-Pro-Lys-Lys-His-Lys-Leu- which is the same as the precursor protein. The carobyl-terminal residue in this polypeptide chain is arginine. The amino-terminal sequence of the light chain is Val-Val-Gly-Gly-Leu-Val-Ala-Leu-Pro-Gly-Ala-?-Pro-Tyr-Ile-. This latter sequence is homologous with the amino-terminal sequence of a number of plasma serine proteases when compared with the chain containing the active-site serine residue. These data suggest that factor XII is converted to factor XIIa by the cleavage of a specific internal arginyl-valine peptide bond. Factor XIIa, in contrast to factor XII, has hydrolase activity toward arginine-containing substrates and is readily inhibited by antithrombinIII and diisopropyl phosphorofluoridate. The inhibitors, in each case, are bound to the light chain of factor XIIa which contains the active-site serine residue.

Amino Acid Sequence↗
PubMed1977

Effect of triiodothyronine treatment on prolactin secretion in patients with amenorrhea-galactorrhea.

In order to determine the role of thyroid hormone in prolactin (PRL) secretion in patients with amenorrhea-galactorrhae, PRL response to 500 mug of iv thyrotropin-releasing hormone (TRH) was studied before and after the administration of triiodothyronine (T3) in 10 patients with amenorrhea-galactorrhea. Seven of these patients were euthyroid and the other 3 had hypothyroidism. The patients in the euthyroid group received 50 mug of T3 daily for 7 days and 75 mug q.d. for the ensuing 14 days. The hypothyroid patients received T3 at progressively increasing doses from 10 mug q.d. to 75 mug q.d. during 34 to 68 days. In the initial test, the elevated basal levels of PRL, 61.9 +/- 9.8 ng/ml (Mean +/- SE) exhibited a slight but insignificant net increase (7.7 +/- 2.1 ng/ml) after TRH injection in the euthyroid group. However, a marked response to TRH with a net increase of 147.2 +/- 26.3 ng/ml from the basal level of 47.3 +/- 11.2 ng/ml was observed in the hypothyroid patients. After treatment with T3, both the basal level (56.9 +/- 8.3 ng/ml) and the net increase (9.9 +/- 3.6 ng/ml) of PRL following TRH stimulation remained virtually unchanged in the euthyroid group. The hypothyroid group, in contrast, displayed a significant depression of both the basal level (26.1 +/- 13.0 ng/ml) and the net increase (33.8 +/- 6.5 ng/ml) of PRL to TRH stimulation. The diminution of the basal levels and responses of thyroid-stimulating hormone (TSH) to TRH stimulation was observed in all cases of both groups. These results suggest that the level of thyroid hormone has little pathogenic role in PRL secretion in euthyroid patients with amenorrhea-galactorrhea, in contrast to its marked effect in hypothyroid patients with amenorrhea-galactorrhea.

Adult↗
PubMed1977

LH concentrations in human maternal and cord serum.

Maternal blood and umbilical cord venous blood were collected immediately after delivery in 32 subjects who had completed normal birth during the 38 to 41 weeks of pregnancy, and the concentrations of human chorionic gonadotropin (hCG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were determined by radioimmunoassay (RIA). The specific LH RIA utilized for the measurement of LH is unaffected by hCG at sample levels as high as 500 IU/ml. HCG concentrations were 10,370 +/- 1,480 mIU/ml (mean +/- SE) in mother's serum and 34.5 +/- 5.2 ml in cord serum, while LH concentrations were 0.729 +/- 0.055 and 0.438 +/- 0.033 ng/ml, respectively. The concentration of all 3 gonadotropins in maternal serum was greater than cord serum and the ratio was markedly high with 302:1 for hCG, while the ratio was smaller for LH, being 1.7:1, while that for FSH was 4.2:1. There was no difference in the levels of LH and FSH in relation to the sex of the fetus.

Adult↗
PubMed1977

Responses of serum gonadotrophins to LH-releasing hormone and oestrogens in Japanese women with polycystic ovaries.

In order to define the abnormality in gonadotrophin secretion in Japanese women with polycystic ovaries (PCO) who rarely show virilization and markedly enlarged ovaries, basal levels of LH and FSH, and responses of serum gonadotrophins to LH-releasing hormone (LH-RH) or oestrogens were determined by radioimmunoassay. Eleven patients with PCO diagnosed by laparotomy or laparoscopy and 30 normal women in the follicular phase were studied. The mean (+/- SD) basal level of LH was significantly higher in patients with PCO than in normal controls (PCO 28.6 +/- 2.4 vs. normal 10.9 +/- 3.0 mIU/ml), while the mean FSH level in PCO patients was not significantly different from that in the normal controls (9.7 +/- 0.7 vs. 11.4 +/- 2.6 mIU/ml). The mean LH/FSH ratio in PCO patients was significantly higher than that in normal controls (3.2 +/- 0.9 vs. 1.0 +/- 0.3). Exaggerated response of LH to LH-RH was observed in PCO patients, while the FSH response was comparable with the normal controls. Ten out of 11 patients with PCO showed LH release exceeding the basal level after bolus iv injection of 20 mg conjugated oestrogens (Premarin), and virtually the same mean net increase in LH from the basal level was obtained in both PCO patients and normal controls. Since the abnormalities in gonadotrophin secretion in Japanese women with PCO are not different from those reported in patients with PCO in Europe and USA, it seems likely that lower incidence of markedly enlarged ovaries and virilization in Japanese patients may be caused by the difference in ovarian response to gonadotrophin.

Adult↗
PubMed1977

Pituitary responses in LH secretion to LHRH during pregnancy.

Thirty-six pregnant women and 15 normally menstruating women were each given 100 microng of synthetic luteinizing hormone releasing hormone (LHRH) by a single intravenous injection. Human chorionic gonadotropin (hCG), luteinizing hormone (LH), and follicle stimulating hormone (FSH) levels were determined by specific radioimmunoassay (RIA) technics. For the determination of the serum LH levels, the LHbeta-RIA method, which is unaffected by hCG at sample levels as high as 500 IU/ml, was used. Serum concentrations of LH and FSH were lower in pregnant women than in the normal women in the follicular and luteal phases. While the release of LH was observed in pregnant women following the administration of LHRH, the average net increase was less than that seen in both the follicular and luteal phases. During pregnancy, there was a progressive decrease in the LH response to LHRH, but no release of FSH.

Adult↗
PubMed1977

Fine structure of noradrenaline containing nerve fibers in the median eminence of female rat demonstrated by in situ fixation of potassium permanganate.

Fine structure of noradrenaline (NA) terminals in the internal layer of the median eminence (ME) was elucidated by in situ fixation of potassium permanganate. The NA terminals in ME contained relatively large cored vesicles (about 1000 A) together with a large number of small core vesicle (400-600 A). The most dominant feature that NA terminals show is the closed contact with ependymal cells and their processes. In the bulging abutting on the contact membrane, some of core vesicles fused or touched the membrane appearing to release the content into intercellular space or take up NA from the space. This finding shows that the NA terminals abutting on the ependymal cells and their processes have a close contact with them and give an important influence on regulation of ependymal function. Our present study further revealed that the NA terminals also had a close contact not only with the axon terminals in which ordinary spherical non-cored vesicles were exclusively present but also with the axonal fibers of neurosecretary system. These findings would infer complicated function of NA in ME.

Animals↗