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Biomedical subjects

M Sakata

Publications and source records attributed to M Sakata.

At least 181 records · Page 10Linked to original sources
PubMed1990

Induction by tumor necrosis factor-alpha of rapid release of immunoreactive and bioactive luteinizing hormone from rat pituitary cells in vitro.

Tumor necrosis factor-alpha (TNF-alpha) is secreted by activated monocytes and other immune cells. This paper reports studies on the effects of TNF-alpha on the releases of pituitary hormones such as luteinizing hormone (LH), follicle-stimulating hormone, prolactin (PRL) and adrenocorticotropic hormone (ACTH). The addition of recombinant human TNF-alpha (rTNF-alpha) to cultures of pituitary cells resulted in significantly increased releases of gonadotropins, PRL, and ACTH for up to 30 min, but not later. rTNF-alpha, like GnRH, also stimulated the release of bioactive LH. In addition, rTNF-alpha induced production of an interleukin-6 (IL-6)-like molecule by pituitary cells. As IL-6 induces the releases of multiple hormones from pituitary cells, our data suggest that rTNF-alpha may stimulate the releases of multiple pituitary hormones through IL-6 production as well as by its direct action on pituitary cells.

Adrenocorticotropic Hormone↗
PubMed1990

Electrocautery in polycystic ovary syndrome.

The serum levels of bioactive luteinizing hormone (LH), immunoreactive LH, follicle-stimulating hormone (FSH), and testosterone were determined in eleven anovulatory women with polycystic ovary syndrome (PCOS) before and after laparoscopic ovarian cautery. Before treatment, the mean +/- SEM levels of bioactive and immunoreactive LH and testosterone were 53.1 +/- 7.9 mIU/ml, 35.2 +/- 3.9 mIU/ml, and 1.14 +/- 0.13 ng/ml, respectively, which were significantly higher than those of five control women (19.2 +/- 1.6 mIU/ml, 21.4 +/- 1.2 mIU/ml, 0.28 +/- 0.03 ng/ml). After treatment, the mean levels of these hormones decreased significantly, ten women ovulated spontaneously and four conceived. The present results suggests that decreases in the levels of these hormones by laparoscopic ovarian cautery in women with PCOS may result in both restoration of the ovulatory cycle and the achievement of pregnancy.

Adult↗
PubMed1990

[Morphological detection of placental anticoagulant protein-I (PAP-I) in human placenta].

It has been reported that placental anticoagulant protein-I (PAP-I) inhibits the intrinsic and extrinsic pathways of blood coagulation and also the reconstituted prothrombinase activity. However, morphological study on the distribution of PAP-I in whole placenta or in placental cells has not been reported yet. We detected the PAP-I antigen, under light- and electron-microscope, by mean of immuno-cytological techniques. PAP-I was also present in microvilli of the placental syncytiotrophoblast cells and their cortical cytoplasm beneath the villi.

Annexin A5↗
PubMed1989

Effects of ONO-3708, an antagonist of the thromboxane A2/prostaglandin endoperoxide receptor, on platelet aggregation and thrombosis.

The beneficial effects of an antagonist of the thromboxane A2/prostaglandin endoperoxide receptor, 7-[2 alpha,4 alpha-(dimethylmethano)-6 beta-(2-cyclopentyl-2 beta- hydroxyacetamido)-1 alpha-cyclohexyl]-5(Z)-heptenoic acid (ONO-3708) on thrombosis were examined. ONO-3708 at 0.1-3 microM inhibited the human platelet aggregation induced by thromboxane A2, prostaglandin H2, collagen, ADP (secondary phase) and epinephrine (secondary phase) without affecting prostanoid synthesis and the content of cyclic AMP in platelets. The in vivo effects, on coronary thrombosis in this case, were examined in two canine models. ONO-3708, 3 to 300 micrograms/kg i.v., prevented dose dependently the coronary thrombosis induced by partial obstruction of the coronary artery. ONO-3708, 3 micrograms/kg per min i.v., significantly prevented electrically stimulated coronary thrombosis without affecting systemic blood pressure and heart rate. These results indicate that the thromboxane A2/prostaglandin endoperoxide receptor could play an important role in the pathogenesis of thrombosis and that ONO-3708 may have therapeutic advantages in preventing thrombosis.

Animals↗
PubMed1989

Studies on GnRH agonist suppression of estrogen production in patients with endometriosis.

The chronic administration of GnRH agonists to women results in the reversible suppression of estrogen production by the ovary. In the present study, the mechanism of the GnRH agonist suppression of estrogen production was investigated in patients with endometriosis. During the treatment with intranasal buserelin spray, the concentration of serum estradiol-17 beta (E2) was suppressed to near-castrate levels. Despite this marked suppression of serum E2, immunoreactive LH and FSH levels in serum were not changed. On the other hand, serum bioactive LH was markedly reduced. It was also observed during the treatment that the pituitary LH pulse disappeared and pituitary response to exogenous GnRH was significantly suppressed. In contrast, ovarian response to human menopausal gonadotropin (hMG) was not altered during the treatment. These findings suggest that the GnRH agonist suppression of estrogen production in the patients with endometriosis is through both suppression of the secretion of biologically active LH and the reduction of the LH pulse, but not through a direct inhibitory effect on ovarian estrogen biosynthesis.

Administration, Intranasal↗
PubMed1989

Disposition of acetone, methyl ethyl ketone and cyclohexanone in acute poisoning.

A case of coma due to the drinking of a liquid cement for polyvinyl chloride resin, containing acetone, methyl ethyl ketone, cyclohexanone and polyvinyl chloride is described. The patient also simultaneously ingested the alcoholic beverage, sake. After gastric lavage, plasma exchanges and direct hemoperfusions, the patient recovered. The concentrations of these chemicals in plasma and urine were analyzed at various time intervals to estimate the clearance. The elimination half lives for acetone and methyl ethyl ketone were 18 hours and 10 hours, respectively. Although cyclohexanone made up the largest component in the solvents, the blood level was extremely low and a large amount of cyclohexanol, a metabolite of cyclohexanone was detected in the blood and urine. The glucuronide metabolite of cyclohexanol was also estimated after the hydrolysis with beta-glucuronidase. Since the conversion of cyclohexanone to cyclohexanol is known to be catalyzed by alcohol dehydrogenase, possible interactions between sake ingestion and cyclohexanone metabolism is proposed.

Acetone↗
PubMed1989

[Solitary ureteral metastasis from cervical cancer: a case report].

A case of solitary ureteral metastasis from cervical cancer in a 36-year-old female is reported. On April 4, 1988, the patient visited the gynecological department of our hospital with abnormal genital bleeding. Colposcopy and cervical biopsy revealed invasive cervical cancer, and computerized tomography (CT) indicated right hydronephrosis. She was referred to the urological department for further examinations. Right retrograde pyelography (RP) however could not be performed. On April 13, 1988, the patient underwent laparotomy due to acute abdomen, which was proved to be caused by subileus. On exploration, a tumor was found in the lower one third section of the right ureter, whereupon a right nephroureterectomy was performed because primary ureteral tumor was suspected. The histology of the ureteral tumor revealed it to be a metastatic squamous cell carcinoma identical to that obtained from punch biopsy of the cervix. At that time, a hysterectomy could not be done because of invasive cervical cancer. Following the operation, radiation therapy was conducted for primary cervical cancer. At present, 7 months after the operation, the patient is alive with good performance status.

Adult↗
PubMed1988

Preliminary report on the use of danazol in the treatment of endometrial adenomatous hyperplasia.

Since the authors recently reported that danazol inhibits the growth of human endometrial cancer cells in vitro, a clinical trial was initiated to examine whether danazol can regress adenomatous hyperplasia, a precursor of endometrial adenocarcinoma. Danazol was used for 3 months in the treatment of five patients with a history of hypermenorrhea and irregular uterine bleeding. Within a 9-month follow-up period, all patients were symptom-free, and none of the specimens obtained by endometrial biopsy showed the presence of adenomatous hyperplasia. These findings suggest that danazol has a potential application in the treatment of patients with endometrial adenomatous hyperplasia. A possible mechanism of action of the compound in adenomatous hyperplasia is also discussed.

Adenoma↗
PubMed1988

Strategies for the in vivo inhibition of endogenous atriopeptin.

Pharmacological strategies have been employed to manipulate the response to atriopeptin (AP-28; ANF 99-126) in rats. These approaches include: heparin infusion which blocks the natriuresis-diuresis produced by exogenous AP infusion or by acute volume expansion; and autoimmune rats with endogenous antibody that blocks the natriuresis-diuresis produced by administration of exogenous AP or by acute volume expansion in anesthetized rats. Administration of the pressor analog 1-deamino-arg8-vasopressin (dAVP) to rats produces an elevation in systemic and right atrial blood pressure and markedly increases atriopeptin blood levels. The dAVP also produces a delayed natriuresis-diuresis which is effectively blunted in the autoimmune or heparin treated rats. The above approaches provide tools, in the absence of a specific receptor antagonist, with which to validate the intrinsic involvement of AP in physiological, pharmacological, or pathophysiological events.

Animals↗