Preimplantation Developmental Competence of Bovine and Porcine Oocytes Activated by Zinc Chelation.

After sperm-oocyte fusion, intracytoplasmic rises of calcium (Ca) induce the release of zinc (Zn) out of the oocyte (Zn sparks). Both phenomena are known to play an essential role in the oocyte activation process. Our work aimed to explore different protocols for activating bovine and porcine oocytes using the novel zinc chelator 1,10-phenanthroline (PHEN) and to compare developmental rates and quality to bovine IVF and parthenogenetic ionomycin-induced embryos in both species. Different incubation conditions for the zinc chelator were tested, including its combination with ionomycin. Embryo quality was assessed by immunofluorescence of SOX2, SOX17, OCT4, and CDX2 and total cell number at the blastocyst stage. Even though blastocyst development was achieved using a zinc chelator in bovine, bypassing calcium oscillations, developmental rates, and blastocyst quality were compromised compared to embryos generated with sperm-induced or ionomycin calcium rise. On the contrary, zinc chelation is sufficient to trigger oocyte activation in porcine. Additionally, we determined the optimal exposure to PHEN for this species. Zinc chelation and artificial induction of calcium rise combined did not improve developmental competence. Our results contribute to understanding the role of zinc during oocyte activation and preimplantation embryo development across different mammalian species.

High prevalence of infection with a single hepatitis C virus genotype in a small rural community of Argentina.

BACKGROUND: During the years preceding this study, we noticed a relatively unusual high number of individuals with elevated alanine aminotransferase (ALT) levels in O'Brien, a small rural town in Argentina. Moreover, four individuals from this town underwent liver transplantation owing to hepatitis C virus (HCV)-induced liver cirrhosis. These findings prompted us to conduct a large population-based survey to evaluate the prevalence of HCV in this community. METHODS AND RESULTS: A total of 1637 individuals were studied. The overall HCV-seroprevalence was 5.7% (93/1637), being slightly higher in men (45/769; 5.9%) than in women (48/868; 5.5%). HCV seroprevalence increased with age, reaching a peak rate of 23.9% among individuals between 61 and 70 years of age. HCV RNA was present in 82.7% of all HCV seropositive individuals identified and 100% of them were infected with genotype 1b. ALT elevations were detected in 44% of HCV+ patients and were only observed among viremic individuals. Hepatitis B virus infection was also prevalent (52%) among HCV-seropositive patients. The most common risk factor associated with HCV transmission identified was the apparent use of inadequately sterilized glass syringes by a health care provider serving the community; however, other risk factors may have also played a role in the dissemination of HCV. CONCLUSIONS: Our findings provide an explanation for the relative high number of individuals with elevated ALT levels observed in this community and form the basis of future prospective studies on the natural history of genotype 1b infection.