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Biomedical subjects

S Sakamoto

Publications and source records attributed to S Sakamoto.

At least 793 records · Page 44Linked to original sources
PubMed1981

Biosynthesis of prostaglandins from arachidonic acid by the rat ovary.

Biosynthesis of prostaglandins (PGs) from 14C-arachidonic acid was studied using homogenates of the ovaries from immature rats. In ascending order of metabolizing potency were, the ovaries from untreated rats, from rats treated with pregnant mare's serum gonadotropin (PMS), and from PMS-human chorionic gonadotropin (hCG) treated rats. Among the radioactive metabolites extracted, PGE2 and 6-keto PGF1 were purified and identified by silicic acid column-, thin layer-, reversed phase partition chromatographies, and radiogaschromatography. Production of PGE2 and 6-keto PGF1 was observed in homogenates of the ovaries of intact and PMS-hCG treated rats at conversion rates of 0.72; 0.43% and 7.62; 2.31%, but not by PMS treated rat ovaries. Treatment with PMS-hCG activated metabolism of arachidonic acid into radioactive metabolites including PGE2 and 6-keto PGF1 to a large extent. Accordingly, it is concluded that luteinizing hormone and hCG play a significant role in the biosynthesis of PGs by the rat ovarian follicle.

6-Ketoprostaglandin F1 alpha↗
PubMed1981

Isolation and immunochemical localization of collagenase in mouse peritoneal macrophages.

Collagenase was isolated from the culture medium of thioglycollate-stimulated mouse peritoneal exudate macrophages. The macrophage collagenase activity was inhibited by goat anti-mouse bone collagenase antibody, indicating that macrophage collagenase immunologically cross-reacts with mouse bone collagenase. The enzyme was localized in mouse peritoneal macrophages by indirect immunofluorescent antibody technique. Distinct granular fluorescence was observed intracellularly in most thioglycollate-stimulated macrophages, whereas slight or no fluorescence was observed in non-stimulated control macrophages.

Animals↗
PubMed1981

Vincristine and prednisolone therapy in blast crisis of chronic myelogenous leukaemia in childhood.

6 cases of chronic myelogenous leukaemia (CML) blast crisis in childhood were treated with vincristine and prednisolone (V-P). In 3 terminal transferase ((TdT)-positive cases, blast cells were lymphoid in appearance. All 3 TdT-positive patients entered a complete remission but developed meningeal leukaemia. The mean duration of survival from the onset of blast crisis was 32 months. In 3 TdT-negative cases, V-P therapy was ineffective. The results of this study suggest that V-P therapy is more effective for CML blast crisis in childhood with TdT positive blast cells and that prophylactic central nervous system treatment is necessary to prevent meningeal leukaemia.

Adolescent↗
PubMed1981

Stimulatory effect of chlorpromazine on prolactin secretion in anencephalic infants.

The effect of chlorpromazine on serum levels of PRL was studied in two anencephalic infants without identifiable hypothalamic tissue. After a single im injection of chlorpromazine, serum concentrations of PRL rose about 3-fold. This result indicates that chlorpromazine stimulates PRL release by directly acting on the pituitary gland in humans.

Anencephaly↗
PubMed1981

The mobilization of plasma lipids by histamine in dogs.

The aim of the present work was to study the mechanism of the mobilization of plasma lipids produced by histamine in the dog, in vivo. The increase of plasma lipids by histamine in vivo was suppressed by cimetidine, but not by diphenhydramine. Although, histamine increased the level of plasma adrenaline, adrenaline does not appear to contribute to the lipolysis stimulated by histamine, because propranolol and alprenolol, beta-adrenergic blocking agents, did not affect the lipolysis stimulated by histamine. From these data it is concluded that the increase of plasma lipids in vivo is not attributable to the release of adrenaline from adrenal glands by histamine, but is produced by the stimulation through H2-receptors in fat cells.

Adrenergic beta-Antagonists↗
PubMed1981

Effect of prolactin on the secretion of dehydroepiandrosterone (DHEA), its sulfate (DHEA-S), and cortisol by the human fetal adrenal in vitro.

The effect of prolactin on the secretions of dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S) as well as that of cortisol were studied in vitro in order to investigate the possible regulatory role of prolactin on steroidogenesis of the human fetal adrenal at mid-gestational age. The addition of 0.5 microgram/ml of human prolactin to the incubation medium produced a significant (P less than 0.05) increase in DHEA, DHEA-S, and cortisol secretion. These results indicate that prolactin has a regulatory role in steroidogenesis in the human fetal adrenal at mid-gestation.

Adrenal Glands↗
PubMed1981

Synthesis of prolactin by human decidua in vitro.

Human decidua, chorion, amnion and placenta from the 1st., 2nd. and 3rd. trimesters of gestation were investigated for synthesis and secretion of prolactin by in vitro incubation of these tissue fragments in medium 199. Prolactin content in decidua was found to be significantly higher than that in chorion, amnion or placenta at any stages of gestation. During 6 hours of incubation, decidua secreted significantly more prolactin into medium than did chorion, amnion or placenta. The amount of prolactin secreted by decidua was significantly higher than the prolactin content in tissue before incubation. Decidua were also incubated in medium 199 with or without actinomycin-D (20-200 micrograms/ml), puromycin (200 micrograms/ml) or cycloheximide (100-200 micrograms/ml) for 12 hours. Both total prolactin secreted into medium and prolactin content in tissue after incubation were significantly lower than the control without inhibitor. Decidua of 2nd. trimester of gestation was noted to secrete more prolactin into medium than decidua of 1st. or 3rd. trimester of gestation. In further studies, 3H-leucine (200 muCi) was incubated for 12 hours with decidua (10 grams) from 2nd. trimester of gestation. The incorporated protein in medium or tissue was extracted, fractionated by gel filtration through Sephadex G-100 column and by 10% SDS-polyacrylamide gel electrophoresis. Peaks of 3H count and immunoreactive prolactin in gel slices were coincident with the peak of standard pituitary prolactin at gel slices' No. 31 (Rf = 0.62). These results demonstrate that prolactin is synthesized and secreted by human decidua, which is identical to human pituitary prolactin. The synthetic activity is most prominent in the decidua of the 2nd. trimester of pregnancy.

Amnion↗
PubMed1981

Two cases of acute myelogenous leukemia with high terminal deoxynucleotidyl transferase activity responding to vincristine-prednisolone treatment with complete remission.

Increased TdT activity was demonstrated in 2 cases of AML. One of them had Ph1 positive chromosome due to a standard translocation of t(9:22). Treatment with cytosine arabinoside, daunorubicin, 6-mercaptopurine and prednisolone was ineffective or only partially effective. Switching to the vincristine and prednisolone therapy resulted in a complete remission in both cases.

Adult↗
PubMed1981

Some properties of starches of grain amaranths and several millets.

Starch granules were prepared from seeds of Amaranthus hypochondriacus L., A. caudatus L., proso millet, Japanese barnyard millet and foxtail millet. Amylose contents and the distribution of alpha-1,4 linked chain of amylopectin were determined by gel filtration of isoamylase-debranched starches. Some physical and chemical properties of the starches were also examined by scanning electron microscopy, X-ray diffractometry, photopastegraphy, and differential scanning calorimetry, together with starch-granule susceptibility to amylases. The existence of both normal and waxy types in the same species of a grain amaranth, A. hypochondriacus L., was confirmed. A. caudatas starches were identified to consist of mainly typical amylopectin and 5-7% amylose. The starches have some unique properties, namely, high starch-granule susceptibility values to amylases as well as those of A. hypochondriacus and unique pasting properties.

Amylases↗
PubMed1981

[Effects of bromocriptine on FSH and LH secretion in women with euprolactinemic anovulation (author's transl)].

A few reports have been given that Bromocriptine effected not only on the hyperprolactinemic anovulations but also on the euprolactinemic anovulations. This study was performed to examine the underlying mechanism, 5 mg of Bromocriptine was daily administered for 30 days to 38 women with euprolactinemic anovulations. The basal secretions of FSH, LH and Prolactin and also the responsiveness to LH-RH, TRH and estradiol were examined. 31.6% of oligomenorrhea, anovulatory cycle and Ist. grade amenorrhea showed ovulatory cycles, however, no ovulations were observed in IInd. grade amenorrhea. The basal levels of FSH and LH significantly increased but the basal levels of Prolactin decreased by Bromocriptine. The responsiveness of FSH to LH-RH was markedly promoted but LH showed no significant change. Serum FSH was suppressed in estrogen loading test after Bromocriptine, which was poorly changed before. On the other hand, serum LH was markedly elevated by estradiol after Bromocriptine, which showed poor elevation before. These results conclude that: 1) Ovulation is induced by Bromocriptine administration in euprolactinemic anovulations. 2) Bromocriptine promotes the FSH and LH secretion from the pituitary and also promotes the reserve of FSH in the pituitary. 3) Bromocriptine promotes the sensitivity of the estrogen feedback in the hypothalamus.

Adolescent↗
PubMed1981

Ultrastructure of the nidatory site in tubal pregnancy.

Nidatory site of pre-abortive tubal pregnancy, obtained from 41 years old women was studied in both scanning and transmission electron microścopes. The nidatory site was basically composed of anchoring villi, trophoblastic column and shell, fibrinoid layer and marked round cell infiltration. In spite of the histologically normal appearance of the chorionic villi, villous syncytiotrophoblast ultrastructurally showed slight tendency of degeneration, being concurrent with blighted ovum. The trophoblast at the trophoblastic column and shell contained a great amount of glycogen which decreased at the distal part near and in the fibrinoid layer. The degenerating trophoblast were surrounded by massive fibrin bundles and fibrin bundles and fibrin-like deposits. The more the degeneration of the trophoblast proceeded, the more the fibrin deposits accumulated around the trophoblast. The trophoblast which ran over the fibrinoid layer was scarcely observed and if there, it showed marked degenerative appearance. These findings suggest the possible role of fibrinoid layer: protection of maternal tissue from trophoblastic invasion, not the protection of fetus from maternal immunological attack. No direct contact such as tight junction, desmosome and so on between trophoblast and maternal cell was observed in the present study, suggesting the formation of special connection with the allogeneic cell, one of the unique characters of the trophoblast, is expressed only when it is primitive in the early stage of development.

Adult↗
PubMed1981

Effect of nitrous oxide on human bone marrow cells and its synergistic effect with methionine and methotrexate on functional folate deficiency.

5-Methyltetrahydrofolate homocysteine methyltransferase activity in human bone marrow cells obtained from patients undergoing surgical operation became low after about 4 hr of nitrous oxide (N2O) anesthesia. The deoxyuridine suppression test performed on these bone marrow cells also became abnormal after about 6 hr of N2O anesthesia. The incorporation of [3H]thymidine into DNA in the bone marrow cells preincubated with methionine or methotrexate was much higher after N2O anesthesia than before anesthesia. Since N2O and methionine or methotrexate have a synergistic effect on depletion of functional folate, N2O alone or in combination with methionine or methotrexate might be of value for cancer treatment and deserve clinical trials.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗