TASK DEFINITION: Given an abstract, indicate which of the provided candidate titles (Option1 and Option2) best describes it (respond with the text of the title, not option1/2).
PROBLEM: Abstract: The effects of aging on calcium and bone metabolism have not been systematically examined in men. To identify age-related alterations in vitamin D and PTH physiology and to assess their impact on skeletal health, we studied 62 normal men, aged 30-92 yr. The men were in excellent health, and none had any evidence of metabolic bone disease and/or known risk factors for osteopenia. Serum 25-hydroxyvitamin D (25OHD) concentrations declined steadily with advancing age (r = -0.47; P less than 0.001), and there was a corresponding decline in serum 24,25-dihydroxyvitamin D [24,25-(OH)2D] levels (r = -0.41; P less than 0.001). Serum 1,25-(OH)2D concentrations, however, did not vary over this age range (r = -0.07; P = NS). Plasma PTH levels increased with aging (r = -0.24; P less than 0.001), and there was a concomitant increase in urinary cAMP excretion (r = 0.38; P less than 0.001). Renal function (creatinine clearance) clearly declined with increasing age (r = -0.71; P less than 0.001). In conjunction with these changes in calcium metabolism, radial and vertebral bone mineral content declined. Whereas the fall in radial bone mineral content (single photon absorptiometry) at both proximal and distal sites was slight, there was a marked decrease in vertebral bone mineral content, as measured by quantitative computed tomography (r = -0.72; P less than 0.0001). The fall in vertebral bone mineral content correlated well with the declines in serum 25OHD and 24,25-(OH)2D concentrations (r = 0.47; P less than 0.001 and r = 0.51; P less than 0.001, respectively) and with the decline in renal function (r = 0.46; P less than 0.001). Multiple regression analysis revealed that the effects of aging on bone mineral content could be accounted for in large part by concomitant changes in mineral metabolism. Both the decline in renal function and the fall in serum 24,25-(OH)2D levels were closely associated with the fall in bone mineral content. These results indicate that a decline in renal function and alterations in vitamin D metabolism occur with aging in normal men. These changes contribute to, if not cause, the associated decline in skeletal mineral content in aging men.
Which is the apt title for the abstract? option1: Alterations in calcium, vitamin D, and parathyroid hormone physiology in normal men with aging: relationship to the development of senile osteopenia. option2: Effects of exercise and anabolic steroids on total and lipoprotein cholesterol concentrations in male and female rats.

SOLUTION: Alterations in calcium, vitamin D, and parathyroid hormone physiology in normal men with aging: relationship to the development of senile osteopenia.

PROBLEM: Abstract: A retrospective evaluation was done of 102 consecutive in in vitro fertilization-embryo transfer (IVF-ET) treatment cycles that culminated in surgical intervention for oocyte pickup. In 35% of these patients, a disparity was noted in the number of mature follicles present on the day of human chorionic gonadotropin administration, compared with the day of surgery. This suggests the occurrence of undetected ovulation. An endogenous luteinizing hormone (LH) surge was detected in 14 of these patients. Another cohort showed evidence of early luteinization without a detected endogenous LH surge. Finally, a group without early luteinization was defined. Possible explanations for these outcomes and the implications for success of IVF-ET are discussed.
Which is the apt title for the abstract? option1: Undetected ovulation in in vitro fertilization-embryo transfer patients. option2: Estrogen and progesterone receptor assays on the vulvar epithelium.

SOLUTION: Undetected ovulation in in vitro fertilization-embryo transfer patients.

PROBLEM: Abstract: Vascular injuries of the lower limb in the presence of extensive soft tissue loss, fractures, or other life-threatening injuries are associated with a high amputation rate. Five patients underwent temporary intravascular shunting during the period of treatment of such injuries. Rapid reperfusion of the limb via such shunts permitted more comprehensive evaluation and management of the lower limb and other associated injuries than would have been possible in the presence of prolonged ischemia.
Which is the apt title for the abstract? option1: Intravascular shunts in complex lower limb trauma. option2: Behavior abnormalities and poor school performance due to oral theophylline use.

SOLUTION:
Intravascular shunts in complex lower limb trauma.