(1/2509) Uterine peristalsis during the follicular phase of the menstrual cycle: effects of oestrogen, antioestrogen and oxytocin.
Uterine peristalsis, directing sustained and rapid sperm transport from the external cervical os or the cervical crypts to the isthmic part of the tube ipsilateral to the dominant follicle, changes in direction and frequency during the menstrual cycle, with lowest activity during menstruation and highest activity at mid cycle. It was therefore suggested that uterine peristalsis is under the control of the dominant follicle with the additional involvement of oxytocin. To test this hypothesis, vaginal sonography of uterine peristalsis was performed in the early, mid and late proliferative phases, respectively, of cycles of women treated with oestradiol valerate and with human menopausal gonadotrophin following pituitary downregulation, with clomiphene citrate and with intravenous oxytocin, respectively. Administration of oestradiol valerate resulted in oestradiol serum concentrations comparable with the normal cycle with a simulation of the normal frequency of peristaltic contractions. Elevated oestradiol concentrations and bolus injections of oxytocin resulted in a significant increase in the frequency of peristaltic contractions in the early and mid follicular phases, respectively. Chlomiphene tended, though insignificantly so, to suppress the frequency of peristaltic waves in the presence of elevated oestradiol concentrations. In the late follicular phase of the cycle extremely elevated oestradiol concentrations as well as the injection of oxytocin resulted only in an insignificant further increase of peristaltic frequency. In the normal cycles, as well as during extremely elevated oestradiol concentrations and following oxytocin administration, the peristaltic contractions were always confined to the subendometrial layer of the muscular wall. The results and the review of literature indicate that uterine peristalsis during the follicular phase of the menstrual cycle is controlled by oestradiol released from the dominant follicle with the probable involvement of oxytocin, which is presumably stimulated together with its receptor within the endometrial-subendometrial unit and therefore acting in an autocrine/paracrine fashion. Since unphysiological stimulation with oestradiol and oxytocin did not significantly increase the frequency of uterine peristalsis in the late follicular phase of the cycle it is assumed that normal preovulatory frequency of uterine peristalsis is at a level which cannot be significantly surpassed due to phenomena of refractoriness of the system. (+info)
(2/2509) Expression of calcium binding protein D-9k messenger RNA in the mouse uterine endometrium during implantation.
To investigate the molecular mechanisms of implantation, we constructed a cDNA library of mouse uteri enriched with pregnancy-induced genes by subtractive hybridization and polymerase chain reaction (PCR). One of the isolated clones was the cDNA for the calcium binding protein D-9k (Cabp9k), which is considered to regulate intracytoplasmic concentration and transport of free calcium ions. Northern blot and in-situ hybridization analyses demonstrated that the Cabp9k mRNA was expressed in the endometrial epithelia, both luminal and glandular, in the uterus at the time of implantation. On pregnancy day 5 it was detected in the luminal, but not in the glandular, epithelia. In the oophorectomized adult mice, progesterone enhanced Cabp9k mRNA expression in the uterus, whereas oestrogen did not. Consistent with this, a nucleotide change was identified in the first intron of mouse Cabp9k gene corresponding to the oestrogen responsive element in the rat Cabp9k gene. Transfer of embryos into the uterine cavity of pseudopregnant mice reduced the expression of Cabp9k mRNA in the glandular epithelium, suggesting that Cabp9k mRNA expression is also regulated by embryonal signal(s). These findings demonstrated that Cabp9k mRNA is expressed in the endometrial epithelia during the implantation period under the control of progesterone and the presence of embryo, and suggest that CaBP9k plays a role in implantation by regulating the local calcium concentrations. (+info)
(3/2509) Production of germfree mice by embryo transfer.
We applied the embryo transfer technique to germfree (GF) mouse production. Embryos harvested from superovulated mice were transferred aseptically, in a sterile environment, to the uterus of GF recipient females which had been mated with vasectomized GF males. One of the recipients became pregnant and delivered offspring. Sterility tests confirmed that the vasectomized males, newborns, recipient female mice, embryo-containing culture media, and the inside of the vinyl film isolator were germfree. These results suggest that the embryo transfer technique can be successfully applied to the production of GF mice. (+info)
(4/2509) Experimentally induced bovine spongiform encephalopathy did not transmit via goat embryos.
Goats are susceptible to experimental challenge with bovine spongiform encephalopathy (BSE). This study set out to investigate whether the transmission of BSE could occur in goats following the transfer of embryos from experimentally infected donor females into uninfected recipient females. The results showed no evidence of transmissible spongiform encephalopathy disease in any of the offspring which developed from embryos from infected donors, nor indeed in any of the recipient females used as surrogate dams. In addition, there was no indication of experimental BSE spreading as either a venereal infection to males used in mating or by maternal transmission to offspring born naturally to experimentally infected donors, although numbers were small. (+info)
(5/2509) Is intracytoplasmic sperm injection necessary for couples undergoing in vitro fertilization-embryo transfer with normal semen analyses but failing hamster egg penetration assays?
PURPOSE: Our purpose was to assess whether in vitro fertilization (IVF)-embryo transfer (ET) candidate couples with basically normal semen analyses but failing zona-free hamster egg penetration assay (HEPA) scores benefit from intracytoplasmic sperm injection (ICSI). METHODS: Twenty consecutive IVF candidate couples with normal-borderline semen analyses and failing HEPA scores were recruited. Mature oocytes obtained from each woman were randomly divided between ICSI (group I; n = 126 oocytes) and standard insemination techniques (group II; 138 oocytes). Fertilization (two pronuclei) and cleavage (2-4 cells) rates were assessed for both groups. RESULTS: There were no statistically significant differences between the two groups with respect to (mean +/- standard error of the mean) fertilization (group I, 63.1 +/- 7.75; group II, 77.8 +/- 4.7%) or cleavage (group I, 87.3 +/- 2.4%; group II, 91.2 +/- 3.5%) rates. CONCLUSIONS: ICSI is not beneficial for IVF-ET when sperm samples demonstrate a failing HEPA score but have normal or minimally compromised semen analysis parameters. (+info)
(6/2509) Retrieval, maturation, and fertilization of immature oocytes obtained from unstimulated patients with polycystic ovary syndrome.
PURPOSE: Our purpose was to determine whether immature oocytes could be retrieved under local anesthesia, whether these oocytes would mature and fertilize in vitro, and whether adequate endometrium development could be obtained after hormonal supplementation. METHODS: Ovum pick-up was performed under local anesthesia. Immature oocytes were cultured and inseminated. To prepare the endometrium, estradiolvalerate was administered in combination with micronized progesterone. RESULTS: Immature oocytes were obtained in all cases. Fifty-six percent (n = 30) of the oocytes developed into metaphase II (MII) after 48 hr of culture, and another 20% reached the MII stage by 72 hr. Normal fertilization was observed in only 10% of oocytes inseminated. No embryonic development occurred, and therefore embryo transfer was not performed in any of the patients. Endometrial microbiopsy was performed in all subjects and endometrial development was considered sufficient in eight patients. CONCLUSIONS: We collected immature oocytes from patients with polycystic ovary syndrome without general anesthesia. In vitro maturation of these oocytes seemed adequate but fertilization rates were poor. Sufficient endometrial quality was obtained after hormonal substitution. (+info)
(7/2509) Enhanced hatching rate of bovine IVM/IVF/IVC blastocysts using a 1.48-micron diode laser beam.
PURPOSE: Our purpose was to test whether zona pellucida (ZP) drilling using a 1.48-micron diode laser beam on bovine IVM/IVF/IVC blastocysts is effective for embryo hatching. METHODS: Blastocysts produced in vitro at day 7 after IVF were divided into control and laser-drilled groups, respectively. RESULTS: When the rates of in vitro development of bovine embryos were examined, the average cleavage rate (> or = two-cell) was 82.3% and the blastocyst rate at day 7 after IVF was 32.5%. Using these blastocysts, when the laser drilling effect was investigated at 48 hr after treatment, the total hatching rate in the laser-drilled group (98.0%) was significantly higher than that in the control group (60.0%) (P < 0.001). Especially, the hatched rate of the laser-drilled group (68.0%) was significantly enhanced compared with that of the control group (30.0%) (P < 0.001). CONCLUSIONS: These results demonstrated that laser ZP drilling on bovine IVM/IVF/IVC blastocysts can significantly increase the hatching rate. (+info)
(8/2509) Production of cloned calves following nuclear transfer with cultured adult mural granulosa cells.
Adult somatic cell nuclear transfer was used to determine the totipotent potential of cultured mural granulosa cells, obtained from a Friesian dairy cow of high genetic merit. Nuclei were exposed to oocyte cytoplasm for prolonged periods by electrically fusing quiescent cultured cells to enucleated metaphase II cytoplasts 4-6 h before activation (fusion before activation [FBA] treatment). Additionally, some first-generation morulae were recloned by fusing blastomeres to S-phase cytoplasts. A significantly higher proportion of fused embryos developed in vitro to grade 1-2 blastocysts on Day 7 with FBA (27.5 +/- 2.5%) than with recloning (13.0 +/- 3.6%; p < 0. 05). After the transfer of 100 blastocysts from the FBA treatment, survival rates on Days 60, 100, 180, and term were 45%, 21%, 17%, and 10%, respectively. Ten heifer calves were delivered by elective cesarean section; all have survived. After the transfer of 16 recloned blastocysts, embryo survival on Day 60 was 38%; however, no fetuses survived to Day 100. DNA analyses confirmed that the calves are all genetically identical to the donor cow. It is suggested that the losses throughout gestation may in part be due to placental dysfunction at specific stages. The next advance in this technology will be to introduce specific genetic modifications of biomedical or agricultural interest. (+info)