Temporal sensitivity of bovine embryos to culture environment after fertilization and the implications for blastocyst quality.

The aim of this study was to examine the temporal sensitivity of bovine embryos to culture environment after fertilization to determine which period, if any, is most critical in determining blastocyst quality. Bovine zygotes produced in vitro were divided into six groups and cultured either in vitro (in synthetic oviductal fluid, SOF), in vivo (in the ewe oviduct) or in a combination of both systems. Development to the blastocyst stage, the ability of the blastocysts to withstand cryopreservation and the relative abundance of several gene transcripts were examined. Culture in SOF for either 2 or 4 days, followed by subsequent culture in the ewe oviduct, resulted in a significantly lower yield of blastocysts than did all other methods, the effect being most marked in embryos that were cultured in SOF for 4 days. In contrast, culture in vivo for the first 2 or 4 days after fertilization followed by culture in vitro did not have such a marked effect on blastocyst development. Blastocysts produced after culture in the oviduct for 6 days had the highest rates of survival over 72 h after warming (100% survival at 24 h; >95% survival at 72 h). The embryos that spent the last 4 days of culture in vivo also had relatively high rates of survival (100% at 24 h, 73.7% at 72 h). Blastocysts produced entirely in SOF had very low rates of survival after vitrification, with <40% viable at 24 h and <20% survival at 72 h. Blastocysts derived from embryos that spent the first 2 days in vivo and the last 4 days in vitro had the lowest rates of survival (6.7%), whereas those that spent the last 2 days only in SOF had intermediate rates of survival (40.6%). These differences were reflected in the relative abundance of transcripts for the Bax gene.

[Assessment of the level of urinary iodine deficiency in children of Senegalese central regions]. / Evaluation de la teneur en iode urinaire chez les enfants des régions centrales du Sénégal.

Iodine deficiency disorders (IDD) are a major public health problem in Senegal, where strategies of salt iodization were adopted in the southern and eastern regions. The aim of this study led in four districts (Koungheul, Bambey, Mekhe and Kebemer), was to estimate by a questionnaire, the women knowleges, attitudes and practices (KAP) concerning IDD, and to measure children urinary iodine excretion by the Sandell-Kolthoff method to assess a potential deficiency. Six hundred ninety eight households were selected covering 1336 women (age 15 to 49 years) and 400 children (age 6 to 12 years). Sixty three per cent of the women knew the goiter, 89% of them considered that it was a disease and only 0.6% knew the role of iodized salt in the treatment. On the other hand, 20% of the children presented a normal range of urinary iodine excretion superior to 100 microg/l, the deficiency was light (50 to 100 microg/l) in 38% of the children, moderate (25 to 50 microg/l) in 27% and severe (< 25 microg/l) in 15% of them. These results show that other Senegalese regions are concerned by iodine deficiency disorders and need information, education and iodine supplementation programmes, notably for children and young women.