Impact of DOM source and character on the degradation of primidone by UV/chlorine: Reaction kinetics and disinfection by-product formation.

The presence of Dissolved Organic Matter (DOM) can exert a strong influence on the effectiveness of the UV/chlorine process. This study examined the impact of five DOM isolates with different characteristics on the degradation kinetics of model contaminant primidone (PM) during UV/chlorine treatment. The formation of Disinfection By-Products (DBPs) from DOM after 15-min UV/chlorine treatment followed by 24 h chlorination was investigated and compared with chlorination alone. The use of chemical probes and radical scavengers revealed that •OH and ClO• were the main radical species responsible for the loss of PM at acidic and alkaline conditions, respectively. All tested DOM isolates significantly inhibited the decay of PM. A strong negative correlation (>0.93) was observed between the decay rate constants of PM and SUVA of DOM isolates, except for EfOM isolate, which induced the strongest inhibitory effect due to its higher abundance in sulfur-containing functional groups (i.e., sink of •OH/Cl• radicals). Compared with chlorination, the formation of Adsorbable Organic Chlorine (AOCl) and Trichloromethane (TCM) during the UV/Chlorine process was enhanced and hindered for low SUVA isolates and high SUVA DOM, respectively. However, Dichloroacetonitrile (DCAN) formation was generally lower for all isolates except for Ribou Reservoir DOM at pH 8.4 because of its high reactive nitrogenous DBP precursors at caustic conditions. However, when normalized to the chlorine consumed, the UV/Chlorine process always led to a lower DBPs formation compared with chlorination alone.

Materno-fetal cardiovascular complications in Turner syndrome after oocyte donation: insufficient prepregnancy screening and pregnancy follow-up are associated with poor outcome.

CONTEXT: Recombinant human GH treatment and oocyte donation (OD) have improved the quality of life in women with Turner syndrome (TS). However, life expectancy is reduced, mainly due to cardiovascular complications. Pregnancy may itself increase that risk and be associated with hazardous materno-fetal outcome. OBJECTIVE: The objective of this study was to evaluate the materno-fetal outcome of ongoing pregnancies beyond 20 wk of gestation obtained by OD in TS. DESIGN: This was a multicenter retrospective study including all assisted reproductive technology centers affiliated with the French Study Group for Oocyte Donation. RESULTS: Among 93 patients, only 37.6% were prescreened with echocardiography or thoracic magnetic resonance imaging. Maternal outcome was dominated by 37.8% of pregnancy-associated hypertensive disorders including preeclampsia in 54.8% and severe eclampsia in four patients. Prematurity occurred in 38.3% and was correlated with pregnancy-associated hypertensive disorder (P = 0.01). The frequency of in utero growth retardation was 27.5%. One fetal demise was linked to eclampsia. Two patients died from aortic rupture after cesarean section in a context of aortic root dilatation. Only 40% of pregnancies were associated with an absolutely normal materno-fetal outcome. CONCLUSIONS: OD pregnancies in TS who have not been managed following recent specific recommendations were at high risk for maternal death by aortic dissection and for preeclampsia and its complications (fetal distress and in utero growth retardation). These recommendations include previous echocardiography, thoracic magnetic resonance imaging, and overnight blood pressure monitoring associated with a tight follow-up during pregnancy. Until future assessment of these recent recommendations, pregnancies obtained in TS after OD must be still considered as very high-risk pregnancies.

Parameters guiding selection of best embryos for transfer after cryopreservation: a reappraisal.

BACKGROUND: The purpose of this study was to evaluate the respective influences of blastomere survival and resumption of mitosis on the outcome of frozen-thawed embryos. METHODS: A retrospective analysis was performed in our centre on 363 thawing cycles, involving 4-cell day 2 grade 1 embryos with <10% fragmentation. RESULTS: A higher implantation rate per transferred embryo was observed when all transferred embryos were characterized by fully intact blastomeres (100% blastomere survival) as compared with damaged embryos (50 or 75% blastomere survival) (22.0 versus 7.2%; P < 0.0001). Moreover, the implantation rate per transferred embryo was significantly higher for cleaved embryos compared with uncleaved embryos (19.7 versus 3%; P < 0.0001). Transfer of fully intact, cleaved embryos resulted in the highest implantation rates compared with transfer of damaged and uncleaved embryos (27.4 versus 0%; P < 0.0001). Intermediate implantation rates were observed when only one of the two criteria was fulfilled (13 versus 11% respectively; P > 0.05). Multivariate analysis showed that the clinical pregnancy rate was influenced by both criteria (odds ratio = 3.4 for transfer of embryos with six or more cells versus embryos with less than six cells. CONCLUSION: The results of our study suggest that the most important factor to predict further embryo development is the total number of blastomeres in transferred embryos, however they are obtained (good survival and/or resumption of mitosis).