Category Archives: Embryos

Activin A and Follistatin Regulate Developmental Competence: DISCUSSION(4)

These results suggest that activin A does not generally support cell proliferation throughout the early development of bovine embryos but rather stimulates it for a limited period or at a limited developmental stage. Activin A may act on bovine embryos until the third cell cycle and may enhance subsequent development of embryos. The activation of embryonic transcription, which follows the transition from maternal to embryonic control of development, is known as zygotic gene activation (ZGA). In bovine embryos, this transition occurs at the 8-cell stage or earlier. The absence of appropriate ZGA leads to the failure of further embryo development beyond the early cleavage divisions. Therefore, the development-enhancing effect of activin A may be associated with ZGA. In addition, bovine embryos normally develop to the 8- to 16-cell stage and are transported from the oviduct into uterus at 3-4 days after ovulation. The developmental period during which addition of activin A to medium affected bovine embryo development in vitro in the present study (prior to the 9- to 16-cell stage at 90 h postinsemination) seems to coincide with the period during which bovine embryos are present in the oviduct in vivo. Since activin A is produced by oviduct epithelial cells in mice and cows, addition of activin A to embryo culture in vitro may reproduce the environment of the cleavage-stage embryos in the oviduct in vivo. proventil inhaler

Activin A and Follistatin Regulate Developmental Competence: DISCUSSION(3)

In recent studies it was shown that activin A during IVM enhanced postcleavage development of bovine oocytes but not the initial cleavage. The present finding that activin A and/or follistatin did not affect the cleavage rate when activin A and/or follistatin was added to mSOF after fertilization is in agreement with these reports. While the number of morulae and blastocysts was affected by addition of activin A and/or follistatin to medium, the quality of morulae and blastocysts, as determined by evaluation of their cell number, seemed to be similar among the groups (Table 1). Buy Advair Diskus Online

Activin A and Follistatin Regulate Developmental Competence: DISCUSSION(2)

One of the findings from this study is that follistatin affects bovine embryo development. Follistatin is an acti-vin-binding protein, and it has antagonizing effects on the actions of activin in pituitary and granulosa cells. Recently, Silva and Knight reported that fol-listatin opposed the stimulatory effect of activin A on blastocyst yield when both activin A and follistatin were added to the medium during IVM of bovine COC. The results from the present study also show that follistatin neutralized the development-enhancing effect of activin A when both cytokines were added to medium during in vitro development at a concentration of 10 ng/m. Moreover, follistatin had a dose-dependent inhibitory effect on the development to morulae and blastocysts whether activin A was added or not. antibiotics levaquin

Activin A and Follistatin Regulate Developmental Competence: DISCUSSION(1)

The results of the present study clearly demonstrate that activin A enhanced the developmental competence of bovine embryos to the morula and blastocyst stages when embryos were cultured under a gas atmosphere of 5% CO2: 5% 02:90% N2. In contrast, follistatin not only neutralized the development-enhancing effect of activin A added to medium but also impeded the developmental competence of embryos by itself. The development-enhancing effect of activin A and the development-impeding effect of follistatin were observed when embryos were exposed to these cytokines up to the third cell cycle of the embryos. ampicillin antibiotic

Activin A and Follistatin Regulate Developmental Competence: RESULTS(3)

Furthermore, the percentages of embryos that developed to morulae (29%) and blastocysts (18%) in the culture with a combination of 10 ng/ml activin A and 100 ng/ ml follistatin were significantly lower (p < 0.01) than those in the control. The total numbers of cells in morulae and blastocysts obtained by culture with activin A and/or fol-listatin are shown in Table 1. There was no significant difference in the total number of cells in morulae or blastocysts among the treatments. antibiotic levaquin

Activin A and Follistatin Regulate Developmental Competence: RESULTS(2)

Effects ofa Combi nation of Activin A and Follistatin

Cleavage rates of presumptive zygotes cultured in mSOF alone (control) and in mSOF containing 10 ng/ml activin A, 10 ng/ml follistatin, or both (10 ng/ml activin A + 10 ng/ml follistatin; 10 ng/ml activin A + 100 ng/ml folli-statin) were all in the range 85-88% and were not significantly different. The percentages of zygotes that developed to the morula and blastocyst stages are shown in Figure 3. As was found in the previous experiment, the percentages of zygotes that developed to the morula and blastocyst stages with addition of 10 ng/ml activin A alone (46% and 32%, respectively) were significantly higher (p < 0.01) than the percentages obtained in the control (38% and 24%, respectively). buy cheap antibiotics

Activin A and Follistatin Regulate Developmental Competence: RESULTS(1)

Effects ofVarious Dosages of Activin A

Cleavage rates of presumptive zygotes cultured in mSOF with various concentrations of activin A (84-88%) were not significantly different. However, the percentages of zygotes that developed to the morula and blastocyst stages increased dose-dependently with addition of activin A from 0.1 to 10 ng/ml. The percentages of zygotes that developed to morulae and blastocysts with addition of > 1 ng/ml activin A (48-54% and 31-41%, respectively) were significantly higher (p < 0.05) than the percentages obtained with no addition of activin A (41% and 25%, respectively). In addition, hatching rates of embryos cultured in mSOF with > 10 ng/ml activin A (17% for both dosages) were significantly higher (p < 0.05) than that for embryos cultured in mSOF with < 1 ng/ml activin A (8-10%). birth control yasmin

Activin A and Follistatin Regulate Developmental Competence: MATERIALS AND METHODS(5)

After fertilization, presumptive zygotes were cultured in mSOF for 0, 12, 22, 40, 70, 100, or 150 h to obtain embryos at the 1-cell, 2-cell, 3- to 4-cell, 5- to 8-cell, 9- to 16-cell, morula, or blastocyst stages, respectively. Then embryos at each developmental stage were finally cultured in mSOF containing activin A or follistatin at concentrations of 10 ng/ml or no addition for up to 220 h postinsemination. The numbers of embryos that developed to the blastocyst and hatched blastocyst stages were recorded at 175 and 220 h postinsemination, respectively. buy flovent inhaler

Activin A and Follistatin Regulate Developmental Competence: MATERIALS AND METHODS(4)

Experiment 3: Effects of a Combination of Activin A and Follistatin

Experiment 3 was conducted to determine the interaction of activin A and follistatin. At 20 h postinsemination, presumptive zygotes were randomly placed in microdrops of mSOF alone (control) and in mSOF containing 10 ng/ml activin A, 10 ng/ml follistatin, or both (10 ng/ml activin A + 10 ng/ml follistatin, 10 ng/ml activin A + 100 ng/ml follistatin). Embryos were cultured for up to 175 h postinsemination. The percentages of presumptive zygotes cleaved were determined at 48 h postinsemination and the percentages that developed to morulae and blastocysts were determined at 120 and 175 h postinsemination, respectively, under a stereomicroscope. Blastocysts that developed in each treatment were collected at 175 h postinsemination and their total number of cells was counted. In addition, morulae cultured in mSOF and in mSOF containing 10 ng/ ml activin A and/or 10 ng/ml follistatin until 120 h postinsemination were also collected and their total numbers of cells were counted. buy yasmin online

Activin A and Follistatin Regulate Developmental Competence: MATERIALS AND METHODS(3)

Experiment 1: Effects ofVarious Dosages of Activin A

The objective of experiment 1 was to determine the effects of various dosages of activin A on early embryonic development. After fertilization, presumptive zygotes were randomly placed in microdrops of mSOF containing recombinant human activin A (Austral Biologicals, San Ramon, CA) at concentrations of 0, 0.1, 1, 10, or 100 ng/ml and cultured for up to 220 h postinsemination. The percentages of presumptive zygotes that cleaved (> 2-cell stage) were determined at 48 h postinsemination and that developed to morulae, blastocysts, and hatched blastocysts were assessed at 120, 175, and 220 h postinsemination, respectively, under a stereomicroscope. canadian neighbor pharmacy

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