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Biomedical subjects

Y Hamada

Publications and source records attributed to Y Hamada.

At least 577 records · Page 32Linked to original sources
PubMed1978

Investigation of mammalian ovulation with an in vitro perfused rabbit ovary preparation.

An in vitro perfused rabbit ovary preparation has been developed to study local factors responsible for the ovulatory process. This preparation enables: (1) isolation of the ovary from systemic influences, (2) direct serial observations of follicle development and ovulation, (3) addition to the perfusing medium of substances that may influence ovulation acting at the level of the ovary, and (4) correlation of the times of individual follicle rupture with ovarian contractile patterns. With this model the temporal requirements for human chorionic gonadotropin in the process of ovulation have been studied. The direct effects on ovulation of prostaglandin F3 alpha (PGF 2 alpha), the antihistamine chlorpheniramine, and calcium deprivation were also investigated. Chlorpheniramine and EDTA each led to inhibition of ovulation and depressed ovarian contractility. The use of the isolated in vitro ovary preparation permits characterization of the local requirements for ovulation.

Animals↗
PubMed1978

The effect of prostaglandins F2alpha and E2 on pregnancy in mice during implantation.

The uterine content of prostaglandins (PGs) increases following insertion of an intrauterine device (IUD). Such IUD-bearing uteri also exhibit impaired decidualization. Although prostaglandins have been shown to be luteolytic in several species, it is not clear that inhibition of decidualization is mediated solely through alterations in ovarian steroidogenesis. In these experiments, ovariectomized, hormone-replaced pregnant mice, as well as intact mice, were treated systemically with either PGE2 or PGF2alpha so that the extraovarian actions of prostaglandins upon decidualization could be segregated from effects mediated by alterations in ovarian steroidogenesis. The results suggest that the effect of PGF2alpha upon decidualization was mediated via an alteration in ovarian steroidogenesis, but that PGE2 acted independently of the ovary. The hypothesis is presented that alterations in the ratio of E to F prostaglandins elicited within the endometrium by an IUD inhibit decidualization at the uterine level, and that this effect might be mediated by impairment of histamine release from endometrial mast cells.

Animals↗