Archive for the ‘Oocyte’ Category


Oocyte Competence for In Vitro Maturation: DISCUSSION(6)

Mar 13, 2013 Author: Walter Mcneil | Filed under: Oocyte

DISCUSSION(6)

Further studies will be necessary to determine the factor(s) responsible for the blocking in metaphase I of the equine oocytes: factor(s) that regulate synthesis and degradation of the MPF components, MPF phosphorylation regulators such as the phosphatase cdc25, or other kinases involved in the regulation of meiotic events such as mitogen-activated protein kinase.

(more…)

  • Comments Off on Oocyte Competence for In Vitro Maturation: DISCUSSION(6)
  • Oocyte Competence for In Vitro Maturation: DISCUSSION(5)

    Mar 12, 2013 Author: Walter Mcneil | Filed under: Oocyte

    Thus, one can speculate that, in incompetent oocytes, a lasting low MPF activity may prevent occurrence of the events that constitute meiotic maturation, i.e., nuclear envelope breakdown, chromosome condensation, and spindle assembly. One could notice that the oocytes with dense chromatin after in vitro culture displayed H1 kinase activity levels comparable to those of oocytes with germinal vesicle. Though the dense chromatin is the beginning of the chromosome condensation, no increase in the H1 kinase activity was yet detectable. The nuclear lamina disassembly occurred around the time of chromatin condensation, but was not detectable with the technique we used. buy yasmin online

    (more…)

  • Comments Off on Oocyte Competence for In Vitro Maturation: DISCUSSION(5)
  • Oocyte Competence for In Vitro Maturation: DISCUSSION(4)

    Mar 11, 2013 Author: Walter Mcneil | Filed under: Oocyte

    DISCUSSION(4)

    MPF activity was analyzed in equine oocytes in relation to their stage of nuclear maturation and the maturation conditions. After in vitro culture, MPF activity was significantly lower in oocytes that remained in the germinal vesicle or dense chromatin stages than in oocytes that reached metaphase I or metaphase II. This is consistent with findings in goat and pig oocytes. buy flovent inhaler

    (more…)

  • Comments Off on Oocyte Competence for In Vitro Maturation: DISCUSSION(4)
  • Oocyte Competence for In Vitro Maturation: DISCUSSION(3)

    Mar 10, 2013 Author: Walter Mcneil | Filed under: Oocyte

    In the present study, oocyte competence for in vitro maturation was influenced by the diameter of the follicle of origin and was higher at the end of the follicular phase than in luteal phase, again supporting our previous observations. The majority of oocytes collected during the follicular phase before the emergence of the dominant follicle were not meiotically competent, in spite of the injection of exogenous gonadotropin. The growth of the dominant follicle induces atresia in subordinate ones but seems to increase the percentage of competent oocytes. A higher percentage of competent oocytes in follicles in early atresia has been suggested in cattle and has been recently shown in the horse. birth control yasmin

    (more…)

  • Comments Off on Oocyte Competence for In Vitro Maturation: DISCUSSION(3)
  • Oocyte Competence for In Vitro Maturation: DISCUSSION(2)

    Mar 9, 2013 Author: Walter Mcneil | Filed under: Oocyte

    DISCUSSION(2)

    All COCs recovered from preovulatory follicles had an expanded cumulus at collection, and half of the enclosed oocytes had completed meiosis. Some COCs recovered from nonpreovulatory follicles had an expanded cumulus at collection, but only a few of the enclosed oocytes had completed meiosis. Similarly, all the compact COCs underwent cumulus expansion during in vitro culture, but not all oocytes completed meiosis, as previously described in mice, pigs, cattle, and horses. Thus, in the horse, cumulus expansion in vivo as well as in vitro is not linked to oocyte nuclear maturation. buy cheap antibiotics

    (more…)

  • Comments Off on Oocyte Competence for In Vitro Maturation: DISCUSSION(2)
  • Oocyte Competence for In Vitro Maturation: DISCUSSION(1)

    Mar 8, 2013 Author: Walter Mcneil | Filed under: Oocyte

    The aim of this study was to investigate the meiotic competence of equine oocytes collected in different physiological stages and to analyze the MPF activity in oocytes after in vitro culture. antibiotic levaquin

    Oocytes were collected by using in vivo ultrasound-guided transvaginal puncture, which allows collection of a well-characterized population of oocytes and comparison of different populations within the same animal. In the present study, we collected 0.5 COCs per nonpreovulatory follicle punctured. There was no effect of the hormonal environment on recovery rate, which supports our previous work. The two rhythms of successive punctures tested, one puncture at the end of the follicular phase plus one during the luteal phase, and repeated punctures during the follicular phase, provided 10-12 COCs per 22 days. Moreover, only 8 of 70 puncture attempts were not performed in the expected conditions.

    (more…)

  • Comments Off on Oocyte Competence for In Vitro Maturation: DISCUSSION(1)
  • Oocyte Competence for In Vitro Maturation: RESULTS(5)

    Mar 7, 2013 Author: Walter Mcneil | Filed under: Oocyte

    RESULTS(5)Histone H1 Kinase Activity

    A total of 190 oocytes were assayed individually for histone H1 kinase activity (171 oocytes in various nuclear stages after in vitro culture, 7 preovulatory oocytes in metaphase II, and 12 oocytes as immature controls). The expected band of phosphorylated histone H1 at 31 kDa was visualized for each oocyte analyzed (Fig. 2, A-C). The intensity of the band varied markedly between oocytes in different nuclear maturation stages and with the maturation conditions (in vitro vs. in vivo). antibiotics levaquin

    (more…)

  • Comments Off on Oocyte Competence for In Vitro Maturation: RESULTS(5)
  • Oocyte Competence for In Vitro Maturation: RESULTS(4)

    Mar 6, 2013 Author: Walter Mcneil | Filed under: Oocyte

    All 301 oocytes with a compact cumulus at recovery were cultured for 30 h. After in vitro culture, 100% of the COCs had an expanded cumulus; 299 oocytes were analyzed for nuclear maturation (two were lost during analysis), and 33% (99 of 299) had reached metaphase II. The maturation rate (oocytes in metaphase II) and the rate of oocytes able to resume or complete meiosis (oocytes with dense chromatin, in metaphase I, or in metaphase II) significantly increased with follicle diameter (p < 0.05 and p < 0.01, respectively); the latter was significantly lower in follicles 5-9 mm (38%, 32 of 84) than in follicles 10-34 mm (76%, 164 of 215; p < 0.01). Oocyte competence for in vitro maturation was influenced by the estrous cycle stage (Fig. 1). ampicillin antibiotic

    (more…)

  • Comments Off on Oocyte Competence for In Vitro Maturation: RESULTS(4)
  • Categories


    Advertising


    Most Popular

    • None found

    Recent Comments

    • None found