Effect of aging on hypothalamic LH-releasing and prolactin inhibiting activities and pituitary responsiveness to LHRH in the male laboratory rat

Hypothalamic content of LH releasing and prolactin inhibiting activities and pituitary responsiveness to LH releasing hormone was measured in young (4 mo.) and aged (26 mo.) Long-Evans rats by in vitro methods. Hypothalamic extracts (0.5 and 1.0 hypothalamic equivalents) from young and aged male rats were incubated with untreated hemisected rat pituitaries in medium 199. Doses of 0.5 and 1.0 hypothalamic equivalents (HE) from both age group stimulated LH secretion. The increase in pituitary LH release stimulated by 0.5 HE from aged male rats was about half that stimulated by 0.5 HE from the young male group (p less than .20). The increase in LH secretion stimulated by hypothalamic extracts of either age group was not associated with a change in pituitary LH content. Although 0.5 and 1.0 HE from young male rats and 1.0 HE from the aged group reduced incubated pituitary prolactin release, 0.5 HE from the aged males did not affect prolactin release. Treatment with hypothalamic extracts also resulted in increased pituitary prolactin concentrations. Pituitaries from young and aged male rats were incubated in medium 199 containing 0, 25, or 100 ng of LH releasing hormone. Although LH releasing hormone stimulated LH secretion in all groups, the increase in release of LH was less in the aged groups than from pituitaries from the young male rats. Pituitary LH content of the aged male group was only about 1/4 that of the young group.

Aging effects on hypothalamic dopamine and norepinephrine content in the male rat

Hypothalamic content of dopamine and norepinephrine was measured in young (4 mo) and aged (24-26 mo) male rats by aluminum oxide adsorption and microfluorescence. Hypothalamic content of both dopamine and norepinephrine was significantly less in aged than in the young groups. Average dopamine content of the young and aged groups was 32.5 +/- 9.3 and 15.6 +/- 2.5 ng/hypothalamus, respectively. Norepinephrine content averaged 47.6 +/- 10.7 and 22.8 +/- 1.8 ng/hypothalamus in the young and aged groups. These data suggested that alterations in hypothalamic catecholamine function contribute to changes in endocrine control mechanisms during aging.

Lessons from the Chinese experience: China's planned birth program and its transferability

This article describes the most salient developments in the planned birth program of the People's Republic of China during the 1970s and discusses the potential for transfer of some features to other countries. Many Chinese activities are of interest because they are designed for a country with scarce resources for development and a low-income population. Some particular program features worth noting are: the encouragement of local initiative and experimentation: specific methods for the diffusion of innovation; and total integration of the health system with other development-political, administrative, economic, and social-at the grass-roots level.

Lymphocyte transformation during dinitrochlorobenzene contact sensitization. An in vitro and in vivo evaluation of the primary immune response in man

An evaluation of cell-mediated immunity in man is described that combines the advantages of an in vitro technique, lymphocyte transformation, with the use of contact sensitization to a primary immunogen, dinitrochlorobenzene (DNCB). DNCB, when coupled to autologous or allogeneic peripheral blood leukocytes, forms a complex, DNCB-antigen, that induces lymphocyte transformation specifically in leukocyte cultures from subjects sensitized to DNCB. Sequential studies of lymphocyte transformation to DNCB-antigen show that specifically reactive lymphocytes are first detected at about 10 days after in vivo application of a sensitizing dose of DNCB and reach a peak at about 14-21 days.

The C-group pachytene bivalent with a locus characteristic for parachromosomally situated particulate bodies (parameres): a provisional map in human males

During prophase stages of the first meiotic division in human males, an autosomal divalent in the C group (autosomes 6-12) characteristically has associated with it, at a specific locus, small, DNA-containing bodies (parameres). A pachytene chromomere map is presented, as is evidence suggesting that the parameres are disposed in two lateral loops, each of which is coaxial with one of the homologs. Stereophotographs of stacks of plates from electron micrographs of serial ultrathin sections show the parameres in their in situ configuration to be composed of tightly compacted fibrils, 85-90 A in diameter.