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Dive into the research topics where Yoshimune Kobayashi is active.

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Featured researches published by Yoshimune Kobayashi.


American Journal of Obstetrics and Gynecology | 1992

The impact of endometriosis on the reproductive outcome of infertile patients

Masato Inoue; Yoshimune Kobayashi; Ikuko Honda; Hideo Awaji; Akikazu Fujii

OBJECTIVE We examined whether the presence and severity of endometriosis affect the reproductive outcome of infertile patients. STUDY DESIGN The conception rates of 2080 infertile women, 1263 who had endometriosis and 817 who did not have endometriosis, were analyzed retrospectively by means of the chi 2 test. Depending on the stage of the disease patients who had endometriosis-associated infertility underwent expectant management, danazol therapy, or minor or major conservative surgery. The patients who failed to conceive after these conventional treatments were enrolled in the in vitro fertilization-embryo transfer program. RESULTS The conception rates were virtually identical regardless of the presence or absence of endometriosis (30.7% vs 30.0%). The outcome of in vitro fertilization-embryo transfer was not affected either by the presence or the severity of the disease. CONCLUSION Endometriosis had no impact on the reproductive outcome of infertile patients in this series unless the anatomy of the pelvic organs was heavily distorted, which can occur in the advanced stages of the disease.


American Journal of Obstetrics and Gynecology | 1981

The effect of prostaglandin synthesis inhibition by indomethacin on ovulation and ovum maturation in the in vitro perfused rabbit ovary

Yoshimune Kobayashi; Rosemary Santulli; Karen H. Wright; Edward E. Wallach

Prostaglandins (PGs) have been implicated in the mechanism of ovulation in several species through the use of PG synthesis inhibitors such as indomethacin. Studies of ovulation in the in vitro perfused rabbit ovary have aided in the delineation of the process of ovulation. This study was designed to determine the effects of indomethacin on follicle rupture and ovum development in the in vitro perfused rabbit ovary preparation. Indomethacin treatment (0.5 microgram/ml) significantly reduced the occurrence of ovulation in gonadotropin-treated ovaries. The percentage of in vitro ovulated ova and ova recovered from unruptured follicles during ovarian perfusion which achieved Metaphase II did not significantly differ between indomethacin-treated and control ovaries (hCG alone). However, increased degeneration of Metaphase II ova was associated with indomethacin treatment. In in vitro culture experiments this degeneration could be prevented by supplemental PGF2 alpha. These results indicate that inhibition of PG synthesis by indomethacin prevents follicle rupture but does not affect ovum maturation, thus providing further evidence that these two processes are distinct phenomena in vitro.


Prostaglandins | 1983

Prostaglandin F2a, an ovulatory intermediate in the in vitro perfused rabbit ovary model☆

Sheldon Schlaff; Yoshimune Kobayashi; Karen H. Wright; Rosemary Santulli; Edward E. Wallach

PGF2a has been proposed as a mediator of mammalian ovulation. To elucidate further the role of PGF2a in the process of ovulation, PGF and PGF2a metabolite were measured by radioimmunoassay in the perfusate of an in vitro perfused rabbit ovary preparation. Perfusion medium samples were collected over a 10 to 12 hour period from ovaries perfused with tissue culture M199 (total volume 150 ml, sample volume 3 ml) to which varying amounts of hCG had been added. [The PGF2a antisera a 40% cross reaction with PGF1a, hence total PGF was measured with this antisera.] Both PGF and PGF2a metabolite showed a linear increase with time and numbers of ovulations. PGF media accumulation was 575 pg/ovary/ovulation/hr and PGF2a metabolite accumulation was 367 pg/ovary/ovulation/hr. Medium prostaglandin content could be correlated with numbers of ovulations, ovulatory efficiency (number of ovulations/total follicles) but not total follicles. These data best fit a model of independent ovulatory units producing PGF2a without recruitment or interaction between them. We infer that PGF and PGF2a metabolites in this system can be used as a direct index of the ovulation process.


Fertility and Sterility | 1985

The relationship between prostaglandins and histamine in the ovulatory process as determined with the in vitro perfused rabbit ovary**Supported by National Institutes of Health grant HD-05948, The Connelly Foundation, and The Mitchell and Lillian Duberstein Foundation.

Hirokatsu Kitai; Yoshimune Kobayashi; Rosemary Santulli; Karen H. Wright; Edward E. Wallach

The process of follicle rupture has been described as an inflammatory reaction in which prostaglandins (PGs) and/or histamine may be involved. With an in vitro perfused rabbit ovary preparation, experiments were carried out for determination of whether a relationship exists among PGs, histamine, and ovulation. PGF2 alpha alone was capable of inducing ovulation when added to the perfusion fluid at 1, 10, and 100 ng/ ml. Effectiveness in achieving ovulation varied directly with the dosage; however, the ovulatory efficiency of PGF2 alpha-treated ovaries was lower than that of ovaries exposed to human chorionic gonadotropin (hCG, 100 IU). PGF2 alpha-induced ovulation could not be blocked by the H2 receptor antagonist, cimetidine. The PG synthesis inhibitor, indomethacin, did not prevent histamine-induced ovulation. Ovulation induced by hCG was partially blocked by the administration of indomethacin; however, the concomitant administration of cimetidine was not associated with further reduction in ovulation. In all but one experimental group, the majority of ovulated ova did not progress beyond the intact germinal vesicle stage unless the ovaries had been exposed to hCG. On the basis of these experiments, PGs and histamine do not appear to be interdependent in their effects on the ovulatory process in vitro.


Fertility and Sterility | 1984

Ultrastructure of ovarian follicles in in vitro perfused rabbit ovaries: response to human chorionic gonadotropin and comparison with in vivo observations**Supported by NIH grant HD-05948, the Connelly Foundation, and the Mitchell and Lillian Duberstein Foundation.

Edward E. Wallach; Yuji Okuda; Hideharu Kanzaki; Yoshimune Kobayashi; Hitoshi Okamura; Rosemary Santulli; Karen H. Wright

Ovulation may be achieved and studied in an isolated perfused rabbit ovary upon inclusion of human chorionic gonadotropin (hCG) in the perfusion fluid. The ultrastructural features of the rabbit ovarian follicle prior to ovulation in vitro were compared with those in vivo. The perifollicular vasculature was also examined in in vitro perfused rabbit ovaries during the preovulatory interval. Granulosa cells of the preovulatory follicle share many ultrastructural features in vivo and in vitro; however, only small amounts of smooth endoplasmic reticulum (sER) were observed in granulosa cells in vitro after hCG. Ovulation after hCG in the in vitro preparation tends to occur earlier (6 hours) than in vivo (12 hours). Thus, there may be insufficient time and/or gonadotropin exposure to permit full functional development of granulosa cells, as reflected by reduced amounts of sER. Degradation of collagen fibrils was less prominent in the theca externa and tunica albuginea in vitro than in in vivo. Perifollicular capillaries became dilated after hCG, but interendothelial gaps were not observed. Disappearance of surface epithelium in the apex of follicles was similar in vitro and in vivo.


Biology of Reproduction | 1981

Ovulation and Ovum Maturation in the Rabbit Ovary Perfused in vitro

Yoshimune Kobayashi; Karen H. Wright; Rosemary Santulli; Edward E. Wallach


Nature | 1980

Inhibitory effect of prolactin on ovulation in the in vitro perfused rabbit ovary.

Yasuo Hamada; Sheldon Schlaff; Yoshimune Kobayashi; Rosie Santulli; Karen H. Wright; Edward E. Wallach


Biology of Reproduction | 1983

Effect of Histamine and Histamine Blockers on the Ovulatory Process in the In Vitro Perfused Rabbit Ovary

Yoshimune Kobayashi; Karen H. Wright; Rosemary Santulli; Hirokatsu Kitai; Edward E. Wallach


Fertility and Sterility | 1985

The relationship between prostaglandins and histamine in the ovulatory process as determined with the in vitro perfused rabbit ovary

Hirokatsu Kitai; Yoshimune Kobayashi; Rosemary Santulli; Karen H. Wright; Edward E. Wallach


Reproduction | 1983

In-vitro fertilization of rabbit ova ovulated in vitro during ovarian perfusion.

Yoshimune Kobayashi; Rosemary Santulli; Karen H. Wright; Edward E. Wallach

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Karen H. Wright

University of Pennsylvania

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Rosemary Santulli

University of Pennsylvania

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Edward E. Wallach

University of Pennsylvania

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Edward E. Wallach

University of Pennsylvania

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Sheldon Schlaff

University of Pennsylvania

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Esther Eisenberg

University of Pennsylvania

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