Efficiency of human oocyte slow freezing: results from five assisted reproduction centres.

It has been demonstrated previously that freezing oocytes within 2 h of retrieval increases the efficiency of cryopreservation via a slow-freezing/rapid-thawing protocol with 0.3 mol/l sucrose (SF/RT 0.3). The aim of this multicentre survey was to verify this observation on a larger scale. This was a retrospective study on the clinical outcome of 510 SF/RT 0.3 cycles divided into two groups: group A, freezing oocytes within 2 h of retrieval; group B, freezing oocytes more than 2 h after retrieval. The rate of best-quality embryos was significantly higher (33.24%) in group A than in group B (16.20%, P < 0.001). Pregnancy and implantation rates were 30.07% and 15.08% in group A versus 8.97% and 4.57% in group B (P < 0.001). Clinical pregnancy rates per thawed and per injected oocyte in group A were 5.53% and 10.41%, versus 1.46% and 2.77% in group B (P < 0.001). The overall yield from oocytes cryopreserved within 2 h of retrieval (group A) was 6.49 implantations per 100 oocytes thawed versus 1.74 for group B (P < 0.001). Embryo quality, pregnancy and implantation rates, and clinical efficiency of thawing cycles were all significantly improved when cryopreservation was carried out within 2 h of oocyte retrieval.

Follicular fluid levels of vascular endothelial growth factor and early corpus luteum function during assisted reproductive technology cycles.

BACKGROUND: The relation between vascular endothelial growth factor (VEGF) and early luteal function has rarely been proven in humans. The purpose of this study was to define the relation between follicular fluid concentrations of VEGF (FF VEGF) and early luteal function at the preimplantation stage during assisted reproductive technology (ART) cycles. METHODS: 71 women were divided into two groups, based on reproductive outcome: women who became pregnant after embryo transfer (ET) (n = 18, Group A) and non-pregnant women (n = 53, Group B). Serum progesterone (Se P) and inhibin A on ET day, and FF VEGF levels were measured in all women. Data were expressed as mean +/- standard deviation. Statistical analysis was performed using Excel Office 98 for Student's t-test, linear regression test and chi-square test. A p value of < 0.05 was considered statistically significant. RESULTS: The groups were comparable for age, ovarian reserve, number and quality of the oocytes retrieved and of the embryos obtained and transferred. FF VEGF levels were increased (4235 +/- 1433 vs 3432 +/- 1231 pg/ml), while Se P and inhibin A levels were significantly reduced (83.1 +/- 34.1 vs 112.0 +/- 58.8 ng/ml and 397.4 +/- 223 vs 533.5 +/- 283 pg/ml, respectively) in the non-pregnant group and were negatively correlated with FF VEGF (r = -0.482, p < 0.05; r = -0.468, p < 0.05) only in pregnant women. CONCLUSION: Much has to be learned about the regulation and role of VEGF during the early luteal phase. We advance the hypothesis that the existence of a negative correlation between FF VEGF/Se P and FF VEGF/inhibin A in pregnant women might indicate the existence of a normal VEGF-mediated paracrine response when Se P and inhibin A levels are decreased. Excess production of FF VEGF and the absence of a correlation between FF VEGF/Se P and FF VEGF/inhibin A in non-pregnant women may be a paracrine reaction to immature luteal vasculature, resulting in luteal dysfunction.

Prevalence of Streptococcus mutans and dental decay in schoolchildren living in Genoa (Italy).

In this study population (105 schoolchildren aged 5.5-11.5 yrs), dental decay was detected in 75.2% and S. mutans in 55.2% of the subjects. The presence of S. mutans was assessed - using the selective GSTB medium - in unstimulated saliva and in pooled occlusal and pooled buccal plaques from the four most posterior teeth. All three samples showed association between S. mutans presence and caries prevalence. Of the two types of plaque, the occlusal not only had a higher frequency of isolation but also a significantly higher proportion of S. mutans. The presence of S. mutans was significantly associated with both caries prevalence and extent of caries experience. Both S. mutans prevalence and S. mutans proportion in plaque increased with the number of decayed teeth present among those sampled. Sucrose consumption between meals appeared to be more correlated with the degree of caries experience rather than with caries or S. mutans prevalence. A second clinical examination was scheduled six months after the first for S. mutans-positive children who either were free of active carious lesions, or were caries-active but without signs of dental decay in the sampled teeth. Caries-active subjects proved to be more prone to new carious lesions than caries-free subjects, who tended to remain caries-free even when they had a high proportion of S. mutans in plaque, thus indicating the basic importance of the host factor in the caries process.