Angiogenesis is the process that drives blood vessel development in growing tissues in response to the local production of angiogenic factors. With the present research the authors have studied vascular endothelial growth factor (VEGF) production in ovarian follicles as a potential mechanism of ovarian activity regulation. Prepubertal gilts were treated with 1250 IU equine chorionic gonadotropin (eCG) followed 60 h later by 750 IU of human chorionic gonadotropin (hCG) in order to induce follicle growth and ovulation. Ovaries were collected at different times of the treatment and single follicles were isolated and classified according to their diameter as small (<4 mm), medium (4-5 mm), or large (>5 mm). VEGF levels were measured in follicular fluid by enzyme immunoassay, and VEGF mRNA content was evaluated in isolated theca and granulosa compartments. Equine chorionic gonadotropin stimulated a prompt follicular growth and induced a parallel evident rise in VEGF levels in follicular fluid of medium and large follicles. Analysis of VEGF mRNA levels confirmed the stimulatory effect of eCG, showing that it is confined to granulosa cells, whereas theca cells maintained their VEGF steady state mRNA. Administration of hCG 60 h after eCG caused a dramatic drop in follicular fluid VEGF that reached undetectable levels in 36 h. A parallel reduction in VEGF mRNA expression was recorded in granulosa cells. The stimulating effect of eCG was also confirmed by in vitro experiments, provided that follicles in toto were used, whereas isolated follicle cells did not respond to this hormonal stimulation. Consistent with the observation in vivo, granulosa cells in culture reacted to hCG with a clear block of VEGF production. These results demonstrate that while follicles of untreated animals produce stable and low levels of the angiogenic factor, VEGF markedly rose in medium and large follicles after eCG administration. The increasing levels, essentially attributable to granulosa cells, are likely to be involved in blood vessel development in the wall of growing follicles, and may play a local key role in gonadotropin-induced follicle development. When ovulation approaches, under the effect of hCG, the production of VEGF is switched off, probably creating the safest conditions for the rupture of the follicle wall while theca cells maintained unaltered angiogenic activity, which is probably required for corpus luteum development.

Although knowledge of feline haemotropic mycoplasmas (haemoplasmas) has dramatically improved in recent years, some issues still remain to be elucidated. The aim of the current study was to evaluate the prevalence of feline haemoplasma infections in blood samples collected from cats in northern Italy. A convenience-sample of 307 cats (40 anaemic; 258 non-anaemic; nine with unknown haematocrit [HCT]) was investigated using polymerase chain reaction assays. Furthermore, the date of blood collection, signalment and clinicopathological data were retrospectively evaluated to assess predictors and risk factors for infection. Haemoplasma infections were highly prevalent in the sample investigated with an overall prevalence of 18.9% (95% confidence interval: 14.5-23.3%). The prevalence for the three feline haemoplasmas was 17.3% for 'Candidatus Mycoplasma haemominutum' (CMhm), 5.9% for Mycoplasma haemofelis (Mhf) and 1.3% for 'Candidatus Mycoplasma turicensis' (CMt). Feline immunodeficiency virus-positive status represented a risk factor for infection with an odds ratio of 4.19 (P=0.02). Moreover, a higher prevalence was observed in summer (odds ratio 1.78; P=0.04) which may be consistent with arthropod-borne disease transmission. Cats infected with Mhf showed significantly lower HCT (P=0.03), haemoglobin values (P=0.02) and red blood cell counts (P=0.04), lower mean corpuscular haemoglobin concentration (P<0.01) and higher white blood cell counts (P<0.01) when compared with non-infected cats.

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A large number of hDAF transgenic pigs to be used for xenotransplantation research were generated by using sperm-mediated gene transfer (SMGT). The efficiency of transgenesis obtained with SMGT was much greater than with any other method. In the experiments reported, up to 80% of pigs had the transgene integrated into the genome. Most of the pigs carrying the hDAF gene transcribed it in a stable manner (64%). The great majority of pigs that transcribed the gene expressed the protein (83%). The hDAF gene was transmitted to progeny. Expression was stable and found in caveolae as it is in human cells. The expressed gene was functional based on in vitro experiments performed on peripheral blood mononuclear cells. These results show that our SMGT approach to transgenesis provides an efficient procedure for studies involving large animal models.SMGT ͉ hyperacute rejection ͉ swine