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Biomedical subjects

K Kurachi

Publications and source records attributed to K Kurachi.

At least 199 records · Page 11Linked to original sources
PubMed1979

An enzyme-immunoassay for estriol.

A practical method was developed for enzyme-immunoassay of serum estriol, with alkaline-phosphatase as a marker enzyme. Alkaline-phosphatase was conjugated with estriol-6-(O-carboxymethyl) oxime using water soluble carbodiimide. The estriol-alkaline-phosphatase complex, which has both enzyme activity and capacity to bind anti-estriol serum, was obtained by Sephadex G-200 gel filtration. This complex, which was stable for at least 3 months at 4 degrees C, was used as enzyme-labelled estriol. Anti-estriol serum raised against estriol-6-(O-carboxymethyl) oxime bovine serum albumin was employed. "Bound and free" estriol were separated by the double antibody method. A linear relation was obtained between estriol concentration and antibody-bound alkaline-phosphatase activity in the range of 0.2-100 ng estriol/ml. In this assay system, cross-reactivity with other steroids was negligible under physiological conditions, and endogenous alkaline-phosphatase, which increases during the late pregnancy, caused no interference. The coefficients of variation were 3.3-14.2% (within assays), and less than 22% (between assays), and the mean recovery rate was 77.5%. Serum estriol values determined by the present method correlated well with those determined by radioimmunoassay (r=0.90 for total estriol; r=0.98 for free estriol). The present method of enzyme-immunoassay is suitable for measurement of serum estriol during pregnancy.

Alkaline Phosphatase↗
PubMed1979

Restoration of the gonadotrophin response to LH-RH and oestrogen administration in patients after molar abortion.

The relation of the hypothalamic-pituitary effect on gonadotrophin secretion and the concentration of serum hCG after molar abortion was investigated. Gonadotrophin release after a bolus injection of LH-RH or conjugated oestrogens was observed in 17 women until 5 months after molar abortion. Little if any response of gonadotrophin was observed at a hCG level of 100 mIU/ml or more, but the response of LH and FSH to LH-RH were restored to normal when the serum hCG level decreased to below 100 mIU/ml. A normal response of LH to conjugated oestrogens was observed at a serum hCG level of 20 mIU/ml or less. These findings suggest that a high level of hCG interferes with pituitary gonadotrophin secretion, that the threshold hCG levels for normal responses of gonadotrophins to LH-RH and oestrogen are 100 and 20 mIU/ml, respectively, and that secretion of gonadotrophins is restored even in the presence of a low hCG level.

Adult↗
PubMed1979

Restoration of oestrogen positive feedback effect on LH release by bromocriptine in hyperprolactinaemic patients with galactorrhoea-amenorrhoea.

Five mg of bromocriptine was administered for 3 weeks to 8 hyperprolactinaemic women with galactorrhoea-amernorrhoea, in whom the response of serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to 100 micrograms of iv LH-releasing hormone (LH-RH) had been evaluated. Twenty mg of conjugated oestrogen (Premarin) was injected iv any day between the 10th and 12th day from the initiation of the treatment, and serum LH levels were serially determined for 120 h. Hyperresponse of LH with normal FSH response to LH-RH was observed in most patients. Bromocriptine treatment for 10 to 12 days significantly suppressed mean (+/- SE) serum prolactin (PRL) levels from 65.1 +/- 23.0 to 10.4 +/- 2.0 ng/ml, while LH (12.6 +/- 2.1 to 24.8 +/- 5.9 mIU/ml) and oestradiol (40.1 +/- 7.6 to 111.4 +/- 20.8 pg/ml) levels increased significantly. Patients on bromocriptine treatment showed LH release with a peak at 48 h after injection of Premarin. The mean per cent increases in LH were significantly higher than those in untreated patients with galactorrhoea-amenorrhoea between 32 and 96 h after the injection. The present results seem to suggest that the restoration of LH-releasing response to oestrogen following suppression of PRL by bromocriptine may play an important role in induction of ovulation in hyperprolactinaemic patients with galactorrhoea-amenorrhoea.

Adult↗
PubMed1979

Suppression of serum levels of luteinizing hormone by short- and long-loop negative feedback in ovariectomized women.

The suppressive effects of short- and long-loop negative feedback on serum levels of LH were assessed after administration of human chorionic gonadotrophin (HCG) and conjugated oestrogens. Fourteen ovariectomized women were injected intravenously with 5 mg conjugated oestrogens, eight of these patients were also given an intramuscular injection of 10,000 i.u. HCG 8 h later, while the other six patients were given a control injection of 0.9% saline. The serum levels of LH decreased by similar amounts in both groups of women. Thirteen other ovariectomized women were initially injected with 10,000 i.u. HCG, i.m., seven of these patients were also given an i.v. ijection of 5 mg conjugated oestrogens 8 h later, while the remaining six patients received a control injection of 0.9% saline. The results showed that conjugated estrogens could further supress the serum level of LH which had been reduced by prior HCG treatment. In six ovariectomized women who received i.m. saline injections at the start of the experiment and 8 h later, the serum levels of LH did not change significantly. It is concluded that the suppression of the serum concentrations of LH by long-loop negative feedback after administration of 5 mg conjugated oestrogens is greater than that by short-loop negative feedback after treatment with 10,000 i.u. HCG.

Adult↗
PubMed1979

Endocrine and androgen-receptor studies in a patient with XY gonadal agenesis.

A 19-year-old phenotypic female with gonadal agenesis and XY karyotype underwent an endocrinologic study. She lacked secondary sexual characteristics and there was posterior labial fusion, absence of vagina, and no gonadal or gonadal duct tissues present at laparotomy. Elevated levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) responded well to intravenous injection of LH-releasing hormone (LH-RH) but did not respond to clomiphene citrate. Both OH and FSH levels were suppressed by administration of testosterone or estrogen. Low serum concentration of testosterone did not respond to human chorionic gonadotropin (hCG) injection. Dihydrotestosterone binding by cultured skin fibroblast revealed the existence of a binding component with low capacity and high affinity. This is the first report of a patient with XY gonadal agenesis in whom androgen receptors in the target cells are demonstrated.

Adult↗
PubMed1978

Platelet factor 4. Crystallization and x-ray diffraction studies.

Human platelet factor 4 was crystallized with ammonium sulfate. The crystals were orthorhombic, space group P21212, with unit cell dimensions a = 78.7 A, b = 80.6 A, and c = 54.6 A. Unit cell volume and mass of the protein (7800 daltons) indicated four or five molecules in each asymmetric unit cell.

Calcium↗
PubMed1978

Afferent fiber connections from lower brain stem to hypothalamus studied by the horseradish peroxidase method with special reference to noradrenaline innervation.

Attempts were made to determine the afferent projections to the anterior hypothalamus including the preoptic area from the lower brain stem by means of the horseradish peroxidase method combined with monoamine oxidase staining to identify noradrenaline (NA) neurons. In addition to this technique, a histofluorescence analysis was performed. NA fibers in the medial part of the anterior hypothalamus were mainly supplied by A1 and A2 NA neuron groups, while the lateral part and periventricular zone received NA terminals from both pontine and medulla oblongata NA neuron groups. Furthermore, the present study indicated that there were direct projections to the anterior hypothalamus from non-noradrenergic neurons in the lower brain stem: nuclei raphe dorsalis, centralis superior, cells in the mesencephalic and pontine central gray matter, nuclei parabrachialis lateralis and medialis, cells around fasciculus longitudinalis medialis.

Afferent Pathways↗
PubMed1978

Activation of human factor IX (Christmas factor).

Human Factor IX (Christmas factor) is a single-chain plasma glycoprotein (mol wt 57,000) that participates in the middle phase of the intrinsic pathway of blood coagulation. It is present in plasma as a zymogen and is converted to a serine protease, Factor IXabeta, by Factor XIa (activated plasma thromboplastin antecedent) in the presence of calcium ions. In the activation reaction, two internal peptide bonds are hydrolyzed in Factor IX. These cleavages occur at a specific arginyl-alanine peptide bond and a specific arginyl-valine peptide bond. This results in the release of an activation peptide (mol wt approximately equal to 11,000) from the internal region of the precursor molecule and the generation of Factor IXabeta (mol wt approximately equal to 46,000). Factor IXabeta is composed of a light chain (mol wt approximately equal to 18,000) and a heavy chain (mol wt approximately equal to 28,000), and these chains are held together by a disulfide bond(s). The light chain originates from the amino terminal portion of the precursor molecule and has an amino terminal sequence of Tyr-Asn-Ser-Gly-Lys. The heavy chain originates from the carboxyl terminal region of the precursor molecule and contains an amino terminal sequence of Val-Val-Gly-Gly-Glu. The heavy chain of Factor IXabeta also contains the active site sequence of Phe-Cys-Ala-Gly-Phe-His-Glu-Gly-Arg-Asp-Ser-Cys-Gln-Gly-Asp-SER-Gly-Gly-Pro. The active site serine residue is shown in capital letters. Factor IX is also converted to Factor IXaalpha by a protease from Russell's viper venom. This activation reaction, however, occurs in a single step and involves only the cleavage of the internal arginyl-valine peptide bond. Human Factor IXabeta was inhibited by human antithrombin III by the formation of a one-to-one complex of enzyme and inhibitor. In this reaction, the inhibitor was tightly bound to the heavy chain of the enzyme. These data indicate that the mechanism of activation of human Factor IX and its inhibition by antithrombin III is essentially identical to that previously shown for bovine Factor IX.

Amino Acid Sequence↗
PubMed1978

Clinical and endocrinological analyses of patients with galactorrhea and menstrual disorders due to sulpiride or metoclopramide.

The clinical courses of galactorrhea and menstrual disorders were studied in 18 women with galactorrhea induced by sulpiride (SLP) or metoclopramide (MCP) given for the treatment of gastrointestinal diseases. The response of PRL and TSH to 500 micrograms iv TRH and the response of LH and FSH to 100 micrograms LRH were assessed by retrospective analysis during treatment in nine patients (six, SLP; three, MCP) and shortly after the end of treatment in nine patients (seven, SLP; two, MCP). The average time from the initiation of treatment to the onset of galactorrhea was 27.2 +/- 4.7 (mean +/- SE) days in the 13 SLP-treated patients and 23.2 +/- 5.8 days in the 5 MCP-treated patients. Five of the SLP-treated patients experienced amenorrhea, four had oligomenorrhea, and one had dysfunctional bleeding. In the MCP-treated patients, oligomenorrhea and dysfunctional bleeding occurred in one each. The average length of time from the end of treatment to disappearance of galactorrhea was 50.0 +/- 7.3 days in the SLP-treated patients and 56.6 +/- 12.1 days in the MCP-treated patients. Cyclic uterine bleeding returned within 2 months after treatment was stopped. Elevated PRL levels with good response to TRH were observed in four of six patients during SLP treatment, and in two of three patients during MCP treatment. Basal PRL levels and response to TRH were normal in almost all patients after the drugs were withdrawn. Normal HL and FSH levels with exaggerated responses of LH to LRH were observed in most patients during treatment, whereas the response of LH to LRH was normal in about half of the patients after treatment. Our findings suggest that hyperprolactinemia in patients treated with SLP or MCP may be in part the cause of both galactorrhea and menstrual abnormalities, and that these symptoms can be reversed by stopping treatment, provided the patients have not taken the drugs for longer than a year.

Adult↗
PubMed1978

Absence of positive feedback effect of oestrogen on LH release in patients with testicular feminization syndrome.

The response of serum LH to exogenous oestrogen administration was studied in 5 patients with testicular feminization syndrome (TFS). The serum LH levels were elevated in all the patients, while serum testosterone levels were within the normal male range. Serum FSH levels were elevated in 4 patients and normal in one patient. Intravenous administration of 100 microgram of LH-RH provoked a further increase in both LH and FSH. Following intravenous injection of 20 mg of conjugated oestrogen (Premarin), the LH levels were serially determined until 120 h in TFS patients, 5 normal males, and 10 normal females during the mid-follocular phase (D7-9). Both TFS patients and normal males showed no LH release following oestrogen injection in contrast to normal females who displayed a significant increase in LH with a peak at 48 to 56 h after the injection. These results seem to suggest that the insensitivity of the hypothalamus to androgen in TFS patients do not affect the sex differentiation of the hypothalamus. The possible role of oestradiol conversion from testosterone in the hypothalamus is discussed.

Adolescent↗
PubMed1978

The time course change after castration in short-loop negative feedback control of LH by HCG in women.

The time course of change in the suppressive effect of human chorionic gonadotrophin (HCG) on luteinizing hormone (LH) and/or LH-beta following castration was studied by a specific LH-beta radioimmunoassay. At 14-50 days after castration 8 women were given 10 000 IU of HCG in a single intramuscular injection (group 1), 5 women were given 2000 IU of HCG in the same way (group 2), and 5 were injected with saline as controls (group 5). In addition, 5 women 6-15 months (group 3) and 7 women 3-8 years (group 4) after castration were given 10 000 IU of HCG. The serum concentrations of HCG in groups 1, 2, 3 and 4 reached peak levels of 209.4, 44.1, 210.6 and 238.6 uU/ml, respectively, 4 h after the HCG injection. The serum LH concentration in group 1 was reduced significantly (P less than 0.01) by HCG administration, but the reductions in the LH levels in groups 2, 3 and 4 after HCG injection were not significantly different from that of the controls. These findings suggest that the threshold of the short-loop negative feedback control of LH in women changes with time after castration.

Adult↗