A comparison of the amino acid sequences demonstrated that Siberian tiger gonadotropins are more homologous with those of porcine than any other commercially available preparation. The present study measured the efficacy of repeated ovarian stimulation with purified porcine gonadotropins on the follicular, hormonal, and immunogenic responses in Siberian tigers as well as on the ability of oocytes retrieved by laparoscopic follicular aspiration to fertilize and cleave in vitro. Controlled rate and vitrification cryopreservation methods were also compared for their ability to support ongoing cleavage following thawing of presumptive 2- to 4-cell tiger embryos generated in vitro. Vitrification supported continued embryonic cleavage in vitro while controlled rate freezing did not. Stereological microscopy indicated an excellent ovarian response with the recovery of quality cumulus-oocyte complexes that apparently fertilized and cleaved in vitro. However, ultrastructural and physiological examination revealed abnormal and unnatural responses such as the failure of some cumulus-oocyte complexes to reach maturity and progestagen levels to approach normalcy. At the same time, analyses of blood for antibodies failed to detect an immune reaction to these foreign gonadotropins in an assay that tested positive for the chorionic gonadotropin-stimulated domestic cat. Together, these observations suggest that porcine gonadotropins may be effective for the ovarian stimulation of tigers but that some modifications to administration protocols are needed to produce a more natural response.
Results are presented that demonstrate a heightened responsiveness of human bronchial epithelial cells (HBECs) toward the complement-derived anaphylatoxin C5a when these cells are exposed to cigarette smoke. This C5a response is possible because we show at both the protein and mRNA levels that HBECs constitutively express receptors for C5a (C5aR, CD88). Control (untreated) HBECs responded to C5a (50 nM) by releasing the proinflammatory cytokine IL-8 at low but significant levels. However, exposure of HBECs to 5% cigarette smoke extract (CSE) for at least 15 min resulted in an increase in the ability of an anti-human C5aR Ab to bind to the cell surface. CSE-treated HBECs responded in a dose-dependent fashion to human recombinant C5a and to a conformationally biased decapeptide agonist of C5a (YSFKPMPLaR) by releasing IL-8. The levels of IL-8 released in response to C5a were significantly greater in CSE-treated HBECs than in control HBECs. Moreover, this C5a-mediated release of IL-8 from CSE-treated HBECs was significantly reduced in the presence of the anti-human C5aR Ab. These results indicate that HBECs constitutively express C5aRs and that exposure to environmental irritants such as cigarette smoke modulates the expression and responsiveness of these C5aRs toward the C5a-mediated release of IL-8.
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