TASK DEFINITION: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
PROBLEM: Abstract: The purpose of this study is to examine plasma cortisol and adrenocorticotropin (ACTH) levels following a brief high-intensity bout of exercise. Each subject (n = 6) performed a 1-min bout of exercise on a cycle ergometer at 120% of his maximum O2 uptake. Blood samples were collected at rest, immediately following the exercise bout, and at 5, 15, and 30 min postexercise. Mean (+/- SE) plasma ACTH levels increased significantly (P less than 0.05) from 2.2 +/- 0.4 pmol/l at rest to 6.2 +/- 1.7 pmol/l immediately following exercise. Mean (+/- SE) plasma cortisol levels increased significantly from 0.40 +/- 0.04 mumol/l at rest to 0.52 +/- 0.04 mumol/l at 15 min postexercise. These data show that brief high-intensity exercise results in significant increases in plasma cortisol and ACTH levels. Furthermore, the temporal sequence between the two hormones suggests that the increase in plasma cortisol levels following brief high-intensity exercise is the result of ACTH-induced steroidogenesis in the adrenal cortex.

SOLUTION: Adrenocorticotropic Hormone

PROBLEM: Abstract: We undertook a study of the separate and combined effects of age and sex on the pulsatile pattern of GH secretion. The 24-h secretory profile of GH was generated by 20-min sampling in 10 young women (aged 18-33 yr), 10 young men (aged 18-33 yr), 8 postmenopausal women (aged greater than 55 yr), and 8 older men (aged greater than 55 yr). A computer-assisted pulse analysis program was used to assess both total GH secretion, as reflected in the 24-h integrated GH concentration (IGHC), and pulsatile secretion, as denoted by pulse frequency, duration, amplitude, and the fraction of GH secreted in pulses during the 24-h period (FGHP). IGHC was significantly greater in women than in men (P less than 0.025) and greater in the young than in the old (P less than 0.003). The mean pulse amplitude, duration, and FGHP were each greater in the young (P less than 0.006, P less than 0.03, and P less than 0.0001, respectively), but not significantly different between the sexes. The mean pulse frequency was not affected by sex or age. The serum concentration of free estradiol, but not free testosterone, correlated with IGHC (r = 0.46; P less than 0.005), pulse amplitude (r = 0.53; P less than 0.001), and FGHP (r = 0.59; P less than 0.0002). After correcting for the effects of estradiol, neither sex nor age influenced IGHC or mean pulse amplitude, while the effect of age on FGHP was reduced from 81% to 29%. Of the indices of GH secretion, FGHP had the strongest correlation (r = 0.43; P less than 0.006) with somatomedin-C. Somatomedin-C declined significantly with age in both sexes. Our results indicate that sex and age have independent and interrelated effects on GH secretion. These effects can be largely accounted for by corresponding variations in endogenous estradiol levels. These observations suggest an amplifying action of estradiol on the neuroendocrine regulation of pulsatile GH release.

SOLUTION: Adolescence

PROBLEM: Abstract: A medical and engineering study was made of 1074 car accidents involving 2520 vehicle occupants. The injuries they sustained were correlated with details of the crash and with contact points inside the cars. Where possible the forces which were generated in the crash were estimated and related to the injuries. In all, 39 car occupants suffered femoral shaft fracture, with an incidence of 1.7% and 0.8% for front and rear seat occupants respectively. Of these, 31 had associated injuries to other regions of the body; these were the cause of 13 of the 14 deaths in this group. Associated injuries were more severe in car occupants who were not wearing seat belts but the incidence of femoral fracture was not significantly different. The mean velocity change (delta-V) causing femoral fracture was 26 mph (42 km/h) and there was a higher incidence of femoral shaft fracture when delta-V was over 30 mph. Estimates of forces needed to cause fracture were higher than those found in cadaver studies. The time to union of femoral fractures did not correlate with the severity of the crash but was longer (mean 19 weeks) than the average for other femoral fractures.

SOLUTION:
Accidents, Traffic