A B S T R A C T Growth hormone (GH) release was studied in adults of normal stature, ages 21-86 yr. The subjects were 85-115% of ideal body weight, between the 5th and 95th percentiles in height, and free ofactive or progressive disease. 9 to 12 individuals in each decade from third to ninth were evaluated. The following criteria of GH status were measured: serum GH concentration, analyzed by radioimmunoassay at halfhour intervals for 4 h after onset of sleep, and at 1-h intervals from 8 a.m. to 4 p.m. in 52 subjects; daily retention of N, P, and K in response to 0.168 U human (h)GH/kg body wt314/day in 18 subjects; and plasma somatomedin C (SmC) level before and during exogenous hGH treatment in 18 subjects.All 10 individuals, 20-29 yr old, released substantial amounts of endogenous GH during both day and night (average peak serum GH obtained during day and night was 7.3 and 20.3 ng/ml, respectively); average plasma SmC was 1.43 U/ml (95% tolerance limits, 0.64-2.22 U/ ml). There was no significant effect of exogenous hGH on elemental balances or on plasma SmC. In contrast, 6 of 12 individuals 60-79 yr old showed the following evidences of impaired GH release: peak waking and sleeping seruim GH < 4 nglml; plasma SmC < 0.38 U/ ml; a significant retention in N, P, and K; and a significant rise in plasma SmC, in response to exogenous hGH.Plasma SmC, serum GH during sleep, serum GH during the day, retentions of N, P, and K in response to exogenous hGH, and rise in plasma SmC in response to hGH were all intercorrelated (P < 0.05). Plasma SmC < 0.38 U/ml corresponded to peak nocturnal serum GH < 4 ng/ml. The prevalence of plasma SmC < 0.38 U/ml

JC virus, a human polyomavirus, failed to grow or produce cytopathic effects in any of a variety of cells tested other than primary human fetal glial (PHFG) cells. Cells tested included other primary human cells and glial cells from other animals. Only a rare cell in inoculated insusceptible human cell cultures produced T or virion antigen. In PHFG cell cultures JC virus produced subtle cytopathic effects, and the majority of progeny remained cell associated. Only a few cells in the heterogenous PHFG cell cultures contained T antigen at 24 h postinoculation, and virion antigen was not detected until 48 h postinoculation. The infectivity of JC virus was resistant to inactivation by ether and by heating at 500 C for 1 h. A three-way minor antigenic relationship was demonstrated among the virion antigens of JC virus, BK virus, and simian virus 40 by neutralization and/or hemagglutination inhibition tests. Serological evidence is presented for the existence of JC virus as a distinct entity before the use of simian virus 40-contaminated poliovirus vaccines and for the nonexistence of an animal reservoir for JC virus infection.

Orang-utans and chimpanzees can discriminate between two objects on the basis of tactile cues and select the one that matches a visually presented sample.

Six adult chimpanzees that had been reared for the first two years of life in restricted laboratory environments were inferior in cognitive skills to eight wild-born control subjects, as assessed by Transfer Index testing. Since both groups had shared the same cages and test experiences after three to four years of age, the role of early experience in cognitive development was underscored.Research with nonhuman primates on the question of whether or not early impoverished rearing might result in cognitive deficits has produced contradictory results and conclusions. Harlow and his associates (Harlow, Harlow, Schiltz, & Mohr, 1971; Harlow, Schiltz, & Harlow, 1969) have reported that totally isolated rhesus monkeys (Macaco, mulatto) were not inferior in learning compared to control monkeys raised in semisocial isolation. In contrast, Davenport and his associates (Davenport & Rogers, 1970) have reported that chimpanzees (Pan) raised in restricted, impoverished conditions were inferior to control, feral-born chimpanzees which had been maintained in social groups. Restrictedly reared chimpanzees appeared to be relatively less adaptive

No abstract