Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0277787 (stigma)
 13,352 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surface cell changes at the apices of preovulatory follicles and ovulations were documented in isolated perfused ovaries from immature rats treated with pregnant mare serum gonadotropin (20 IU) and 48 h later with human chorionic gonadotropin (hCG) (10 IU). A video camera coupled to an inverted microscope and a video recorder captured the preovulatory and ovulatory events at a cellular level. At around 8 h post-hCG, the follicular apex changed from a smooth and optically homogeneous appearance into a rough surface with bleb formation and extrusions of single cells through minute perforations (early stigma formation). At approximately 10 h, a sticky material formed a basketlike structure with trapped cells (late stigma formation). At 12 to 15 h, ovulation took place at a constant speed and with no contractions of the follicular wall. This indicates that ovulation can occur with no visible circumfollicular muscular activity. Furthermore, the observations of a leakage of cells over an extended period of time indicates that the follicular wall is partly digested several hours before ovulation occurs.
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PMID:Ovulation in the isolated perfused rat ovary as documented by intravital microscopy. 261 44

Morphologic studies suggest that the proliferative activity of the ovarian surface epithelium (OSE) may vary during the reproductive life cycle. To further investigate this phenomenon, rabbit ovaries obtained before and after induction of ovulation with human chorionic gonadotropin (hCG) were incubated in medium containing 3H-methylthymidine and processed for autoradiography. Before ovulation, the labeling index (LI) of OSE cells varied from 0.04% to 0.22%. Twelve hours after hCG, the maximal LI (9.02 +/- 0.38%) was seen in OSE cells adjacent to the ovulatory stigma. The LI remained elevated at Days 1 and 5 post-hCG in OSE cells overlying corpora lutea. At Day 12, numerous papillary processes were observed at the apex of each corpus luteum. The maximal LI (16.44 +/- 1.31%) had now shifted to the OSE cells covering these processes. Eighteen days after hCG stimulation, the LI of OSE cells near the corpora lutea had returned to preovulatory levels. A slight increase in the LI of OSE cells not associated with ovulatory sites was also observed after ovulation. This study shows that a significant fraction of OSE cells undergoes DNA synthesis throughout most of the postovulatory period.
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PMID:An autoradiographic study of rabbit ovarian surface epithelium before and after ovulation. 405 31

Our objectives were to determine the rate and extent of follicular evacuation during human ovulation. Female volunteers were given 5000 or 10,000 IU human chorionic gonadotropin to induce ovulation when a follicle reached 18-20 mm. Ovulations were observed via transvaginal ultrasonography and recorded. Images were digitized for computer-assisted analysis. Areas of the follicles, taken to reflect follicular volume, were measured at specific time intervals from the moment of the first leakage of fluid until complete follicular evacuation. Twenty-five ovulations were visualized. In 23 cases (92%) all of the follicular fluid was expelled, but in two cases the follicle failed to empty completely. In all complete ovulations the initial fluid loss was rapid. The time to reach 70% evacuation was 0.9 +/- 0.3 min (+/- SEM). The remaining fluid leaked out more slowly; the mean time to complete follicular evacuation was 6.1 +/- 1.1 min. There was considerable variability in the rates of ovulation (range 6 s to 18.5 min). An association was observed between the type of stigma formed prior to ovulation and the initial rate of fluid loss. The data provide evidence of variability during follicular evacuation, which may in turn influence the successful expulsion of the oocyte from the follicle.
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PMID:Characteristics of follicular evacuation during human ovulation. 1279 30