Infertility sites

There is, however, a possibility that an increased risk of breast cancer might be associated with the state of infertility itself and not with the agents administered to treat it. In a retrospective study of data on 12 193 women evaluated for infertility between 1965 and 1988 at five clinical sites, 292were identified and followed up to the end of 1999. The standardized incidence ratios for in situ and invasive breast cancers in these women were compared with the breast cancer risks in a cohort from the general population (62). Infertile patients as a group had a significantly higher risk of breast cancer (RR = 1.29, 95%CI... 

Leuprolide acetate, a highly potent synthetic analogue of LHRH, is a nonapeptide (5-oxo-Pro-His-Trp-Ser-Tyr-D-Leu-Leu-Arg-Pro-ethylamide acetate) with a molecular weight of -1200 Da. Leuprolide acetate has shown promise for the treatment of infertility, postmenopausal breast cancer, and prostate cancer. Very low oral bioavailability of leuprolide acetate has led to an interest in using the lung as a site for the systemic delivery of leuprolide. Okada et al. [70] have shown that a mixed micellar solution of leuprolide acetate has only 0.05 % oral bioavailability compared to IV leuprolide acetate. This low oral bioavailability may be attributed to poor membrane permeability as well as to significant enzymatic deactivation in the intestine. 

Secretory cells often release vesicles spontaneously at a low rate whereas release rates increase when a stimulus arrives at the release site. For example, miniature synaptic potentials represent spontaneous release from the neuronal presynaptic terminal (Katz, 1966 Stevens, 1993). In contrast, sperm have only one secretory vesicle and, as discussed previously, cells that complete the acrosome reaction prior to egg contact are infertile. This problem may be circumvented, in part, by the fact that large numbers of sperm are produced by mammals, thereby minimizing the consequences of premature acrosome reactions in large populations. However,... 

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