Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.

Input: Consider Input: Abstract: Pulsatile LH secretion was studied to determine if the frequency of LH pulses was altered by the administration of clomiphene citrate (CC; 150 mg) for 5 days during the midluteal phase of the menstrual cycle. Seven normal women received CC or placebo in alternate cycles in a randomized double blind fashion. On the day after drug administration, blood samples were obtained at 15-min intervals for 8 h for serum LH determinations. Daily blood samples were also obtained throughout the luteal phase for determination of serum LH, estradiol (E2), and progesterone. LH pulse frequency increased from 2.4 +/- 0.5 (+/- SEM)/8 h after placebo to 3.9 +/- 0.6/8 h (P less than 0.01) after CC treatment, but pulse amplitude did not change. The transverse mean of serum LH was higher after CC (13.6 +/- 0.5 mIU/ml) than after placebo (8.4 +/- 0.3 mIU/ml; P less than 0.001), and luteal phase length was increased from 13.5 +/- 0.5 to 16.0 +/- 0.4 days (P less than 0.001) by administration of CC. Luteal phase levels of E2 and progesterone measured daily were significantly elevated (P less than 0.01) in CC-treated cycles. These findings suggest that CC increases the frequency of hypothalamic GnRH secretory episodes, perhaps by an action involving a decrease in endogenous opioid peptide activity. Since peripheral progesterone levels were elevated in the CC-treated cycles, E2 may play a permissive role in the ability of progesterone to increase endogenous opioid peptide activity acutely. Furthermore, since the luteal phase was significantly prolonged by an increase in endogenous LH pulse frequency, the slow frequency of LH pulses in the normal late luteal phase may contribute to the onset of luteolysis in the human.

Output: The effect of luteal phase estrogen antagonism on luteinizing hormone pulsatility and luteal function in women.

Input: Consider Input: Abstract: Oxygen consumption (VO2), CO2 production, respiratory quotient, resting metabolic expenditure (RME), and urine catecholamine levels were measured in 52 patients with acute cerebrovascular disease. RME correlated positively with urinary norepinephrine and epinephrine excretion; its maximum value was 187% higher than expected for an uninjured resting person of equivalent age, sex, and size. VO2 correlated positively with the urinary catecholamine excretion. These facts imply that the sympathetic nervous system might directly influence VO2 and RME. Moreover, the hypermetabolic state should be taken into consideration when caring for patients with cerebrovascular disease, as malnutrition might cause weight loss and a decrease in immunity.

Output: Metabolism in acute cerebrovascular disease.

Input: Consider Input: Abstract: Upper airway obstruction is usually diagnosed by visual examination of maximum expiratory and inspiratory flow-volume curves and by calculating a ratio of expiratory to inspiratory flow at 50 percent of vital capacity (mid-vital capacity flow ratio); however, reference values of this ratio have not been well established, and considerable variability exists. The purpose of this study was to examine the range of mid-vital capacity flow ratios in a group of healthy subjects and to determine if some of the variability is accounted for by different maximum inspiratory pressures. We measured maximum expiratory and inspiratory flows at 50 percent of vital capacity from the flow-volume curves, and maximum inspiratory pressures in a group of 60 healthy nonsmokers (30 men and 30 women) whose ages ranged from 21 to 40 years. We found that mid-vital capacity flow ratio (mean +/- SD) was 0.72 +/- 0.19 in men and 0.77 +/- 0.18 in women. The coefficient of variation of the mid-vital capacity flow ratio was 28 percent for men and 23 percent for women. The 95 percent confidence limits for the mid-vital capacity flow ratio were 0.65 to 0.79 for men and 0.70 to 0.84 for women. Maximum inspiratory pressures (mean +/- SD) were 129 +/- 30 cm H2O in men and 91 +/- 16 cm H2O in women, not significantly different from previous studies. Normalizing maximum inspiratory flow for maximum inspiratory pressure did not reduce the coefficient of variation, which became 29 percent in men and 30 percent in women. We conclude that the range of mid-vital capacity flow ratios is wide, and it cannot be reduced by standardizing it for maximum inspiratory pressures.
Output: Maximum flow ratios at mid-vital capacity in young healthy adults.