During each reproductive cycle, a preovulatory surge of gonadotropins induces meiotic maturation of the oocyte in the preovulatory follicle followed by ovulation. Although gonadotropins stimulate cAMP production in somatic cells of the follicle, a decrease in intra-oocyte cAMP levels is required for resumption of meiosis in oocytes. Based on the observed compartmentalization of the cAMP-degrading enzyme, phosphodiesterase, in follicular somatic and germ cells, inhibitors of phosphodiesterase 3 were used to block meiosis in ovulating oocytes in rodents. By this strategy, we demonstrated that fertilization and pregnancy could be prevented without disturbing follicle rupture and normal estrous cyclicity. In contrast to conventional contraceptive pills that disrupt ovarian steroidogenesis and reproductive cycles, the present strategy achieves effective contraception by selective blockage of oocyte maturation and development without alterations in ovulation and reproductive cyclicity. ( J. Clin. Invest. 1998. 102:532-537.)
Aim: To evaluate the significance of the cord blood ischemia-modified albumin (IMA) level as a diagnostic marker for perinatal asphyxia and to determine the associations of IMA levels with the complexity of pregnancy and abnormal Doppler findings, regardless of perinatal asphyxia. Methods: This prospective study included 169 newborns, sixteen of whom had perinatal asphyxia and 33 who were from complicated pregnancies. Doppler measurements were obtained from the uterine, umbilical and middle cerebral arteries, and the cerebro/placental ratio (C/P). IMA was measured by means of commercially available ELISA kits and was expressed as picomoles per milliliter. Results: Ischemia-modified albumin levels were significantly higher in neonates of complicated pregnancies as compared to uncomplicated pregnancies (P < 0.0001). They were higher in newborns with perinatal asphyxia as compared to healthy controls (P = 0.015). The C/P ratio-pulsatility index (PI) showed a significant difference between normal and complicated pregnancies without perinatal asphyxia (P < 0.0001). IMA levels were significantly increased in cases with abnormal C/P ratio-PI. Conclusions: Elevated cord blood IMA levels may be accepted as a useful marker in perinatal asphyxia. Abnormal Doppler examinations are associated with elevated IMA levels in complicated pregnancies.
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