Progesterone from the Cumulus Cells Is the Sperm Chemoattractant Secreted by the Rabbit Oocyte Cumulus Complex

Sperm chemotaxis in mammals have been identified towards several female sources as follicular fluid (FF), oviduct fluid, and conditioned medium from the cumulus oophorus (CU) and the oocyte (O). Though several substances were confirmed as sperm chemoattractant, Progesterone (P) seems to be the best chemoattractant candidate, because: 1) spermatozoa express a cell surface P receptor, 2) capacitated spermatozoa are chemotactically attracted in vitro by gradients of low quantities of P; 3) the CU cells produce and secrete P after ovulation; 4) a gradient of P may be kept stable along the CU; and 5) the most probable site for sperm chemotaxis in vivo could be near and/or inside the CU. The aim of this study was to verify whether P is the sperm chemoattractant secreted by the rabbit oocyte-cumulus complex (OCC) in the rabbit, as a mammalian animal model. By means of videomicroscopy and computer image analysis we observed that only the CU are a stable source of sperm attractants. The CU produce and secrete P since the hormone was localized inside these cells by immunocytochemistry and in the conditioned medium by enzyme immunoassay. In addition, rabbit spermatozoa express a cell surface P receptor detected by western blot and localized over the acrosomal region by immunocytochemistry. To confirm that P is the sperm chemoattractant secreted by the CU, the sperm chemotactic response towards the OCC conditioned medium was inhibited by three different approaches: P from the OCC conditioned medium was removed with an anti-P antibody, the attractant gradient of the OCC conditioned medium was disrupted by a P counter gradient, and the sperm P receptor was blocked with a specific antibody. We concluded that only the CU but not the oocyte secretes P, and the latter chemoattract spermatozoa by means of a cell surface receptor. Our findings may be of interest in assisted reproduction procedures in humans, animals of economic importance and endangered species

Hypercholesterolemia Impaired Sperm Functionality in Rabbits

Hypercholesterolemia represents a high risk factor for frequent diseases and it has also been associated with poor semen quality that may lead to male infertility. The aim of this study was to analyze semen and sperm function in diet-induced hypercholesterolemic rabbits. Twelve adult White New Zealand male rabbits were fed ad libitum a control diet or a diet supplemented with 0.05% cholesterol. Rabbits under cholesterol-enriched diet significantly increased total cholesterol level in the serum. Semen examination revealed a significant reduction in semen volume and sperm motility in hypercholesterolemic rabbits (HCR). Sperm cell morphology was seriously affected, displaying primarily a “folded head”-head fold along the major axe-, and the presence of cytoplasmic droplet on sperm flagellum. Cholesterol was particularly increased in acrosomal region when detected by filipin probe. The rise in cholesterol concentration in sperm cells was determined quantitatively by Gas chromatographic-mass spectrometric analyses. We also found a reduction of protein tyrosine phosphorylation in sperm incubated under capacitating conditions from HCR. Interestingly, the addition of Protein Kinase A pathway activators -dibutyryl-cyclic AMP and iso-butylmethylxanthine- to the medium restored sperm capacitation. Finally, it was also reported a significant decrease in the percentage of reacted sperm in the presence of progesterone. In conclusion, our data showed that diet-induced hypercholesterolemia adversely affects semen quality and sperm motility, capacitation and acrosomal reaction in rabbits; probably due to an increase in cellular cholesterol content that alters membrane related events

The literature of veterinary and animal sciences on the CAB Abstracts Databases: a description and evaluative appraisal of CAB Interational's VETCD and BEASTCD CD-ROM products

CAB International has created specialty subsets of its CAB Abstracts database for release as new SPECTRUM CD-ROM products. Two of these bibliographic products cover all of veterinary sciences and agricultural animal sciences. VETCD contains all the bibliographic records in Index Veterinarius, including those from Veterinary Bulletin, and select records from four other CAB abstracting journals. BEASTCD includes the records from Animal Breeding Abstracts, Nutrition Abstracts and Review Series B, and Dairy Science Abstracts, as well as selected records from two other CAB abstracting journals. The objective of the apportioning of the CAB Abstracts database into specialized subfiles is to produce CD-ROM products that contain all of the CAB Abstracts literature (1973-present) that specifically address the infomratio9n needs of targeted user groups. An objective appraisal of these two SPECTRUM CDs is reported, based on a descriptive and an evaluative study, which compares and contrasts the two CDs with each other and with the full CAB CD-ROM and online files. Comparisons include the elements of organization, completeness of subject coverage, overlap and timeliness

Radioactive gaseous effluents from the core of the AGN-201 reactor at the United States Naval Postgraduate School

A qualitative and quantitative analysis of the core gas generated by the AGN-201 reactor at the United States Naval Postgraduate School was made by analysis of the spectrum of gamma-rays emitted two hours after peak power operations. The principle radioactive isotopes present, based on gamma-ray photopeak energies and half-lives, were found to be Kr85m, KR87, KR88, Xe133, and Xe135. The total activity was found to be 363 + of - microcuries per milliter. The percent of the total activity due to the presence of each isotope identified in the order stated above is 10.2%, 9.0%, 47.4%, 18.6%, and 4.4%. The sources of the remaining 10.4% of the total activity were not identified.http://www.archive.org/details/radioactivegaseo00bredLieutenant Commander, United States NavyApproved for public release; distribution is unlimited