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Biomedical subjects

K Seki

Publications and source records attributed to K Seki.

At least 397 records · Page 22Linked to original sources
PubMed1986

Parallelism in the luteinizing hormone responses to opioid and dopamine antagonists in hyperprolactinemic women with pituitary microadenoma.

Endogenous opiate peptides are considered to inhibit LH secretion via a dopaminergic mechanism, and increased opioid inhibition of LH secretion has been found in some hyperprolactinemic women with a pituitary microadenoma. To assess the role of endogenous dopaminergic tone in the opioid regulation of LH secretion in such patients, LH responses to an opioid antagonist (naloxone) and a dopamine antagonist (metoclopramide) were determined in 11 women with a prolactinoma. Neither naloxone nor metoclopramide administration induced any change in serum LH levels in normal women during the early follicular phase. In contrast, 7 of the 11 hyperprolactinemic women responded to both antagonists with a significant increase in LH levels. The parallelism in the LH responses to both antagonists in these hyperprolactinemic patients lends further support to a functional link between opioid and dopamine regulation of LH secretion.

Adenoma↗
PubMed1986

Responses of growth hormone to metoclopramide in normal women and amenorrheic women with or without hyperprolactinemia.

Response of growth hormone (GH) release to metoclopramide (MCP), a dopamine antagonist, was evaluated in normal women, hyperprolactinemic-amenorrheic patients with pituitary microadenoma and normoprolactinemic-amenorrheic patients. Mean basal concentrations of serum GH and prolactin (PRL) in amenorrheic patients were not significantly different from those in normal women except PRL concentrations in hyperprolactinemic patients. Serum GH concentrations significantly increased after MCP administration in normal women and normoprolactinemic-amenorrheic patients, but not in hyperprolactinemic patients. Dopamine causes modest and transient GH secretion in some subjects. Therefore MCP is not likely to stimulate GH secretion through its effect as a dopamine antagonist, and the mechanism of action of MCP on GH secretion is not known. Although the cause of the absence of GH response to MCP in hyperprolactinemic patients is unclear, it may be related to the increased hypothalamic dopaminergic tone which is operative in such patients or it may reflect a direct action of PRL on hypothalamic-pituitary GH regulation.

Adult↗
PubMed1986

Serum relaxin in patients with invasive mole, choriocarcinoma and persistent trophoblastic disease.

Human chorionic gonadotropin (hCG) is considered to be one of the factors which regulate relaxin secretion in humans. Serum immunoreactive relaxin levels are increased and are detectable by radioimmunoassay both in normal and molar pregnancy. Circulating hCG levels are increased in trophoblastic disease. In the present study, relaxin and hCG levels were sequentially measured in patients with invasive mole, choriocarcinoma and persistent trophoblastic disease. Serum relaxin levels were detectable by radioimmunoassay in these patients before treatment, though they were significantly lower than in normal pregnancy. The corpus luteum of pregnancy is the main source of circulating relaxin in normal pregnancy. The existence of a corpus luteum was confirmed in the 2 patients who underwent laparotomy. Consequently, the corpus luteum may also be the main source of circulating relaxin in trophoblastic disease. Parallel changes in hCG and relaxin levels were observed during the courses of trophoblastic disease. The finding suggests that relaxin secretion is dependent on hCG stimulation in trophoblastic disease in the presence of corpus luteum.

Adult↗
PubMed1986

Increased serum CA 125 levels during the first trimester of pregnancy.

An immunoradiometric assay for an ovarian tumor associated antigen (CA 125) has recently been developed. The CA 125 assay was reported to be fairly sensitive for ovarian cancer. However, elevated CA 125 levels were reportedly observed in 1% of healthy controls, 6% of patients with miscellaneous diseases and 29% of patients with non-gynecological cancer. Therefore, the specificity of the CA 125 assay must be evaluated before its wide clinical application. Furthermore, data on the CA 125 levels in pregnant women have not heretofore been reported. In the present study, CA 125 levels were determined in sera randomly obtained from normal, pregnant women at various weeks of pregnancy and in sera serially collected from women who achieved pregnancy after ovulation induction. When compared with the normal, non-pregnant state, CA 125 levels in pregnant women were significantly higher during the first trimester, but not during the second and third trimesters. Although CA 125 levels in women during the first trimester of pregnancy were significantly lower than those in patients with ovarian cancer, there was a considerable overlap between them. CA 125 levels were undetectable before pregnancy in all of the 8 patients who achieved pregnancy after ovulation induction. They rose during the first trimester of pregnancy in 7 of the 8 patients, and they decreased thereafter to undetectable levels by the end of the first trimester. The increased CA 125 level in the early pregnancy provides an important information for the clinical application of the CA 125 assay. Pregnancy should be ruled out when increased CA 125 levels are found in women during the childbearing years.

Antigens, Neoplasm↗
PubMed1986

Serum relaxin in patients with hydatidiform mole.

Human chorionic gonadotropin (hCG) is considered to be one of the factors that regulates relaxin secretion in humans. However, the secretory pattern of relaxin has not been evaluated in pregnancy complicated by hydatidiform mole, where circulating hCG levels are higher than in normal pregnancy. In the present study, relaxin, progesterone, and hCG levels were determined by radioimmunoassay in patients with hydatidiform mole before and after evacuation of the mole. Serum immunoreactive relaxin and progesterone levels in patients with hydatidiform mole were similar to those in normal women at corresponding weeks of pregnancy before evacuation of the mole, though hCG levels were significantly higher. The fall of relaxin levels after evacuation of the mole was slower than that of hCG or progesterone. This finding may reflect a continued stimulation of the corpus luteum by lower, but still effective, hCG levels persisting after evacuation of the mole. An extraluteal source of relaxin cannot be excluded.

Adult↗
PubMed1985

Suppression of amygdala-kindled seizure in cats by enhanced GABAergic transmission in the substantia innominata.

The chronological effect of intracerebral injection of GABAergic drugs, either muscimol or gabaculine, into the substantia innominata, was examined in amygdala-kindled cats. Results obtained indicate: that the substantia innominata may play a significant role in ictal linkage between a nonmotor system such as the amygdala and the motor mechanism responsible for amygdala-kindled convulsion, and that the GABA terminals in the substantia innominata exert a suppressive action toward convulsive seizure generalization of amygdala origin.

Amygdala↗
PubMed1985

A case of malignant hemangioendothelioma of the stomach.

A case of malignant hemangioendothelioma of the stomach is reported. The patient was a 21-year-old female who developed bloody stool. Pathological studies on the stomach revealed a gastric submucosal tumor. This tumor was growing on the outside of the stomach wall and formed a large abdominal mass. Evidence of metastases was detected in the liver, omentum and parietovisceral peritoneum. Biopsies were taken of the gastric mucosa and the metastatic lesions of the liver and omentum, and histological studies on these specimens led to the diagnosis of malignant hemangioendothelioma. A laparoscopic examination yielded very interesting findings: the presence of small red tumors on the omentum and the parietovisceral peritoneum. The usefulness of laparoscopic examination in the diagnosis of malignant hemangioendothelioma of the stomach is stressed.

Adult↗
PubMed1985

Increased thyroid-stimulating hormone response to thyrotropin-releasing hormone in hyperprolactinemic women.

The TSH response to TRH and basal thyroid function were studied in 21 unselected women with hyperprolactinemia. The mean serum free T4 (FT4) concentration was significantly lower in hyperprolactinemic women than in normal women. The mean basal TSH concentrations were similar, but the incremental TSH response to TRH was significantly greater in hyperprolactinemic women than in normal women. Increased dopaminergic inhibition of TSH release has been reported in hyperprolactinemic women. The low serum FT4 concentration in hyperprolactinemic women may be the result of increased dopaminergic inhibition of TSH release, and the increased pituitary TSH reserve may reflect increased TSH storage due to dopaminergic inhibition of basal TSH release. Alternatively, though less likely, the low serum FT4 concentration may be the result of direct action of PRL on the thyroid, and the low FT4 concentration may, in turn, lead to the increased pituitary TSH reserve.

Adenoma↗