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Biomedical subjects

M Arai

Publications and source records attributed to M Arai.

At least 541 records · Page 30Linked to original sources
PubMed1988

Fine-structural and immunohistochemical study of anterior pituitary cells of Snell dwarf mice.

Snell dwarf mice display remarkable retardation of growth after birth and are known to lack prolactin (PRL), thyroid stimulating hormone (TSH) and growth hormone (GH). The aim of this study was to determine the reason for these hormonal deficiencies. We examined the fine structure of the gland and its immunohistochemical staining pattern with respect to antisera raised against PRL, TSH, GH, adrenocorticotrophic hormone (ACTH) and luteinizing hormone (LH). The gland of control mice reacted immunohistochemically against all antisera used, whereas only ACTH-producing cells (ACTH cells) and LH-producing cells (LH cells) were distinguished in the dwarf mice. ACTH cells in dwarf mice varied in cell shape, although they were similar in size to those of controls. The distribution of secretory granules in the cytoplasm varied from cell to cell. LH cells in the dwarf mice showed immature features, having poorly developed rough endoplasmic reticulum and Golgi apparatus. The cells were about half the size of controls, and secretory granules were smaller. In dwarf mice, non-granulated cells were encountered in addition to granulated ACTH and LH cells. Some of them formed small clusters, characteristic cell junctions being found between the cells; they thus appeared to be follicular cells. The above results suggest that hormone deficiency in Snell dwarf mice is a result of a defect in the hormone-producing cells in the gland.

Animals↗
PubMed1988

Quantitative analysis of a novel pregnancy-associated protein in trophoblastic diseases, normal pregnancy and healthy female subjects.

By means of the Laurell rocket technique, a novel pregnancy-associated protein was measured in the serum of patients with trophoblastic diseases as well as in pregnant women. In 52 normally-menstruating women, the serum levels were below the detection limit in 40 (76.9%); 50 women (96.2%) had levels of less than 2.0 U/ml, and none had levels above 2.1 U/ml. Of 25 patients with a hydatidiform mole, 23 (92.0%) had elevated levels (greater than 2.2 U/ml). In 84 healthy pregnant women, the levels rose from being undetectable before 5 weeks to a plateau in the second trimester. The results suggest that the appearance of this protein in serum is associated with trophoblastic activity.

Biomarkers, Tumor↗
PubMed1988

Clinical effectiveness of a new cervical indwelling catheter in the management of premature rupture of the membranes: a Japanese collaborative study.

The aim of this multiinstitutional study was to evaluate a new cervical indwelling catheter in 84 patients with premature rupture of the membranes at less than 33 weeks' gestation. The average time of insertion of the catheter was 29.1 weeks' gestation, at an average of 2.0 days after rupture, and was left in place for an average of 6.5 days. The mean birth weight was 1417 gm. The mortality rate and the incidence of respiratory distress syndrome were 5.7% and 11.9%, respectively. Amniotic fluid culture was positive in 39.1% of patients before catheter insertion and only 4.3% at the time of delivery. Infection was noted in only four of 84 infants. The incidence of infection was very low in those treated for 3 days or more after catheter insertion.

Adult↗
PubMed1988

Antimycobacterial activities in vitro and in vivo and pharmacokinetics of dihydromycoplanecin A.

The in vitro activity of dihydromycoplanecin A (DHMP A), a new cyclic peptide antibiotic, was compared with those of antimycobacterial drugs such as streptomycin, isoniazid (INH), rifampin, and ofloxacin against several clinically isolated species of mycobacteria, including Mycobacterium tuberculosis, M. intracellulare, and M. kansasii. DHMP A demonstrated stronger activities than other drugs against all species of mycobacteria tested at concentrations of less than 0.0125 to 25 microgram/ml. A marked synergism between DHMP A and INH was demonstrated by the checkerboard technique against M. tuberculosis, M. intracellulare, and M. smegmatis, and the synergistic effect was observed by treatment of the culture of M. smegmatis with DHMP A for at least 3 h prior to treatment with INH. It was also shown that both absorption and excretion of INH in mice were faster than those of DHMP A. On the basis of these results, combination therapy with DHMP A and INH was successfully carried out in experimental tuberculosis in mice infected with M. bovis Ravenel. After a single intravenous administration of 10 mg of DHMP A per kg, its half-life in serum in mice was about 0.5 h and in dogs it was 5.5 h. A single oral administration to dogs of 12.5 mg/kg gave a peak of 5.0 micrograms/ml at 3 h. In these experiments, urinary recoveries within 48 h were 21.0% in mice and 25.2% in dogs. The tissue distribution level of DHMP A in mice after oral administration was in the order of liver greater than kidney greater than serum greater than spleen = lung. The 50% lethal doses of DHMP A for mice were more than 6,000 mg/kg orally and 1,840 mg/kg intraperitoneally.

Administration, Oral↗
PubMed1988

Effects of transforming growth factor-beta on deoxyribonucleic acid synthesis and iodine metabolism in porcine thyroid cells in culture.

The effect of transforming growth factor (TGF)-beta on DNA synthesis and iodine metabolism was studied in cultured porcine thyroid cells. TGF-beta dose-dependently inhibited DNA synthesis stimulated by both insulin-like growth factor I and epidermal growth factor but did not affect the number or affinity of receptors for the two growth factors, suggesting that TGF-beta inhibits postreceptor events responsible for initiation of DNA synthesis. TGF-beta was a potent inhibitor of iodine metabolism. When porcine thyroid cells were cultured with TSH for 3 days in the presence of TGF-beta, TSH-induced iodide uptake and organification were reduced at rates that were dependent on the TGF-beta concentrations. The inhibition was detectable at TGF-beta concentrations as low as 50 pg/ml, and complete suppression was seen at 1 ng/ml. Only 6 h of exposure to TGF-beta resulted in a significant inhibition of TSH-induced iodine metabolism. Treatment of thyroid cells with TGF-beta for 3 days did not reduce cAMP production stimulated by TSH. Moreover, the intracellular cAMP level of thyroid cells cultured with TSH plus TGF-beta did not differ from that of cells cultured with TSH alone. TGF-beta decreased iodide uptake stimulated by forskolin or 8-bromo-cAMP. These results strongly suggest that TGF-beta inhibits TSH-stimulated iodine metabolism, at least in part, by affecting events subsequent to cAMP production. The physiological role of TGF-beta remains to be determined, but it may be involved in the regulation of thyroid cell growth and function.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1988

The inhibitory effect of iodide on growth of rat thyroid (FRTL-5) cells.

The effect of iodide on growth of rat thyroid cells (FRTL-5) was studied. TSH-stimulated cell growth was inhibited by iodide in a concentration-dependent manner, and an effect of iodide was detected at 10(-6) mol/l. KClO4 or 1-methylimidazole-2-thiol blocked the effect of iodide, suggesting that iodide uptake and its organification are required to produce the inhibitory effect of iodide on cell growth. Iodide not only decreased TSH-stimulated cAMP production in FRTL-5 cells but also cell growth induced by cAMP. These observations suggest that iodide inhibits TSH-stimulated growth of the cells by attenuating cAMP production and also by acting on the step(s) distal to cAMP generation. The inhibitory effect of iodide was also seen in growth stimulated by insulin, insulin-like growth factor-I or 12-O-tetradecanoyl phorbol 13-acetate, suggesting multiple sites of action of iodide in the process of growth of FRTL-5 cells.

Animals↗
PubMed1988

[Radiation therapy of intracranial germ cell tumors].

The results of radiation therapy in 31 patients with intracranial germ cell tumors have been analyzed. The five-year survival rates were 70.1% for germinomas and 38.1% for teratomas. Three patients with germinoma have since died of spinal seeding. The prophylactic irradiation of the spinal canal has been found effective in protecting spinal seeding, since no relapse of germinoma has been observed in cases that received entire neuraxis irradiation, whereas teratomas and marker (AFP, HCG) positive tumors did not respond favorably to radiation therapy, and the cause of death in these patients has been local failure. Long-term survivors over 3 years after radiation therapy have been determined as having a good quality of life.

Adolescent↗
PubMed1988

[Effects of cepharanthin on leukopenia and thrombocytopenia caused by CDDP-ACR-CPA therapy of ovarian cancer].

Effects of cepharanthin (50 mg/day, i.v.) an alkaloid of bis-coclaurin type, were studied on leucopenia and thrombocytopenia caused by CDDP-ACR-CPA (CAP) therapy against ovarian cancer. The study was carried out with 44 therapy courses on 17 patients of ovarian cancer receiving CAP administration. Nineteen of the 44 courescin loaded cepharanthin. The minimum number of leucocytes was found on 15.2 +/- 4.4 and 17.2 +/- 2.1 days after CAP-administration with and without cepharanthin, respectively. Leucocyte count 21 days after CAP-administration compared to that before the administration were 90.1 and 56.8% in cepharanthin and non-cepharanthin groups, respectively, which indicate a significant difference (p less than 0.05). As to the platelet count, cepharanthin group also showed attendant toward earlier recovery of thrombocytopenia than non-cepharanthin group. We conclude that the administration of cepharanthin during CAP therapy promotes the recovery from leucopenia and thrombocytopenia.

Adult↗