A new combined in-vitro test model for the identification of substances affecting essential sperm functions [published erratum appears in Hum Reprod 1997 Nov;12(11):2580]

Binding of mammalian spermatozoa to the zona pellucida and the induction of the acrosome reaction are prerequisites for successful oocyte fertilization. It has been postulated that xenobiotics that are released in the environment as well as exposure to pharmaceutical medications may be associated with reproductive problems in men and wildlife. Examining physiological and non-physiological effects of particular compounds on sperm functions requires high quality in-vitro test systems. We established a reliable combined in-vitro test system with bovine gametes and evaluated if aliquots of pooled post-thaw spermatozoa are suitable for examining essential sperm functions. Using cryopreserved semen, the PSA-FITC/Hoechst 33258 staining procedure was applicable to evaluate the acrosomal status and cell viability. In the bovine hemizona assay, hemizona indices revealed no differences between cryopreserved and fresh semen. Treatment of post-thaw bovine spermatozoa with progesterone (1 microM or bovine follicular fluid (20%) induced the acrosome reaction from 12% (untreated spermatozoa) to 25% (P < 0.001) and to 22% [corrected] (P < 0.01), respectively. Incubation of both compounds (1 microM progesterone and 20% follicular fluid) raised the percentage of acrosome-reacted spermatozoa to 30% (P < 0001). Our results demonstrate that cryopreserved semen can be integrated into an in-vitro screening model for reproductive toxicology testing. Pooled, cryopreserved bovine spermatozoa will thus permit reproducible experiments for clinical and basic science purposes and may also be applicable for the human system.      

参三七皂甙Rg1对实验性血栓形成的影响及其机制探讨

用大鼠动静脉血栓形成模型,研究参三七皂甙Rg₁抗血栓作用。结果表明,参三七皂甙Rg₁可明显降低实验性血栓形成,对大鼠血浆纤溶系统亦有明显作用,可升高血浆中组织纤溶酶原激活物(t-PA)活性和活性型t-PA百分比,降低组织纤溶酶原激活物抑制剂(PAI)活性。同时利用培养大鼠血管内皮细胞实验,发现Rg₁可以剂量依赖性提高血管内皮细胞一氧化氮(NO)释放。提示Rg₁抗血栓作用与增强纤溶系统活性,促进血管内皮NO释放有关。     

Process evaluation of the community support connections merger

Community Support Connections (CSC) is the result of the merger of four private not-for-profit community health care agencies. The purpose of this research project was to evaluate the progress of CSC toward its stated goal: improvement of coordination and accessibility of health services. As of this writing, more than one year into the merger, managers, staff and volunteers believe that the goals of serving more clients more completely through case management are being achieved.     

Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11

In a large collaborative screening project, 370 men with idiopathic azoospermia or severe oligozoospermia were analysed for deletions of 76 DNA loci in Yq11. In 12 individuals, we observed de novo microdeletions involving several DNA loci, while an additional patient had an inherited deletion. They were mapped to three different subregions in Yq11. One subregion coincides to the AZF region defined recently in distal Yq11. The second and third subregion were mapped proximal to it, in proximal and middle Yq11, respectively. The different deletions observed were not overlapping but the extension of the deleted Y DNA in each subregion was similar in each patient analysed. In testis tissue sections, disruption of spermatogenesis was shown to be at the same phase when the microdeletion occurred in the same Yq11 subregion but at a different phase when the microdeletion occurred in a different Yq11 subregion. Therefore, we propose the presence of not one but three spermatogenesis loci in Yq11 and that each locus is active during a different phase of male germ cell development. As the most severe phenotype after deletion of each locus is azoospermia, we designated them as: AZFa, AZFb and AZFc. Their probable phase of function in human spermatogenesis and candidate genes involved will be discussed.      

Determinants of acquisition of MR imaging units in an era of prospective payment

A survey was undertaken to examine the impact of Medicare's Prospective Payment System (PPS) and other recent changes in the health care environment on providers' decisions regarding acquisition of high-cost technologic equipment. The survey group included 199 hospitals and freestanding imaging centers known to have acquired magnetic resonance (MR) imaging units, as well as a random sample of 400 hospitals whose acquisition decisions were unknown to the authors. Fifty-eight percent of the known adopters and 61% of the randomly selected hospitals responded to the survey. Nonadopters' decisions were dominated by economic considerations, including the high cost of MR imagers and concerns about Medicare's reimbursement policies. Competition and a desire to provide the highest quality of care are counterbalancing the retardant effects of PPS, however, and are stimulating widespread diffusion of MR imagers.