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1.  Partnership effects in general practice: identification of clustering using intra-class correlation coefficients. 
Although most United Kingdom general practitioners (GPs) work together in a shared professional arrangement termed 'partnership', little is known about the nature of such partnerships. We report the results of a survey of 61 general practice partners in 15 group practices and their attitudes to prescribing and managerial issues related to participation in a commissioning group. Intra-class correlation coefficients (ICCs) were used to explore how these individually held attitudes clustered within groups. The low ICCs found for attitudes relating to prescribing issues suggested that GPs acted individually in this respect, while, in contrast, responses to managerial questions clustered strongly in partnerships, implying that managerial attitudes were more likely to be shared within partnerships. The ICC statistic is a useful tool for exploring homogeneity and heterogeneity within general practice partnerships.
PMCID: PMC1314729  PMID: 14702906
2.  Activin promotes oocyte development in ovine preantral follicles in vitro 
Activins have been implicated as important regulating factors for many reproductive processes. The aim of this study was to determine the effect of activin A on the development of ovine preantral follicles in vitro. Mechanically isolated preantral follicles (161 ┬▒ 2 microm) were cultured for 6 days in the presence of human recombinant activin A (0, 10 and 100 ng/ml). Half of the medium was replaced every second day and follicle diameters were measured. Conditioned medium was subsequently analysed for oestradiol content using a delayed enhancement lanthanide fluorometric immunoassay (DELFIA). At the end of the culture period, follicles were fixed and processed for histology, after which oocyte diameter and granulosa cell death were measured. There was significant follicle growth over 6 days in all groups (p < 0.001). Activin, at both concentrations, increased follicle growth over control levels by Day 6 (p < 0.05). Oocyte diameters were also significantly increased by Day 6 of culture in all groups (p < 0.05), with 100 ng/ml activin increasing oocyte diameter over control levels (p < 0.05). Activin, at both concentrations, increased oestradiol production on Day 2 of culture, but this increase was not sustained during the culture period. Moreover, activin did not have any effect on antrum formation or follicle survival. In conclusion, activin promoted ovine preantral follicle and oocyte growth in vitro, but did not accelerate follicle differentiation over a six-day culture period. These results support a paracrine role for activin A during early oocyte and follicular development.
PMCID: PMC280721  PMID: 14613548

Results 1-3 (3)