Evidence that oxytocin is a physiological component of LH regulation in non-pregnant women.

BACKGROUND: Regulation of the LH surge is central to the functioning of the female ovulatory cycle. In animal models, oxytocin has been shown to alter LH activity. Oxytocin advanced the LH surge and, conversely, oxytocin receptor antagonists inhibited full production of the LH surge in rats. Few data exist on the possibility that oxytocin modulates LH in women. METHODS: Ten non-pregnant women participated in this study over two menstrual cycles. One cycle was a control cycle, and the other a trial cycle; the two were separated by at least one cycle. When the diameter of an ovarian follicle was >15 mm, a subject was allocated at random into either a control or treatment group. In a control cycle, volunteers received normal saline; in a treatment cycle, volunteers received an oxytocin antagonist (atosiban). RESULTS: For treatment cycles, the maximum LH concentration was significantly less than that in control cycles (42.1 +/- 6.2 versus 60.3 +/- 8.3 IU/l respectively; P < 0.05). Maximum FSH and estradiol concentrations were not significantly different between the two groups. CONCLUSIONS: The results indicated that inhibition of endogenous oxytocin affects the endocrinology of the ovulatory cycle in women, and strongly suggest that oxytocin has a role in the physiological processes of LH regulation.

Predictive value of left ventricular ejection fraction in stem cell transplantation.

We evaluated predictive value of left ventricular ejection fraction at rest (REF) and its increment with exercise (deltaEF) on autologous and allogeneic stem cell transplantation mortality. In a 7 year period, a total of 163 patients evaluated for stem cell transplantation were studied. All were followed for at least 3 months after the transplant. REF was discriminatory for peritransplant mortality only in younger (<43 years) patients (n = 66), particularly those who underwent autologous transplantation (n = 30). Resting ejection fraction was not a discriminator for early death in any other subgroup. Cardiac reserve (deltaEF) was significantly lower in patients (n = 35), who died early. The finding was most prominent in younger patients who underwent autologous transplantation (n = 26). Combination of decreased REF and low deltaEF (n = 18) was associated with high peritransplant mortality (56%), after both autologous and allogeneic transplantation. A low REF with an appropriate deltaEF (n = 43) was associated with a 19% peritransplant mortality and no deaths in the autologous group. These observations indicate that resting ejection fraction is of only limited value for pretransplant evaluation. However, measurement of cardiac reserve during exercise can provide important prognostic information before stem cell transplantation.