Age-related changes in uptake and release on L-[3H]noradrenaline in brain slices of senescence accelerated mouse

High K+ and N-methyl-D-aspartate (NMDA) evoked L-[3H]noradrenaline (NA) release to a similar degree in the brain slices of 1-month-old senescence-accelerated resistant mice (SAM-R/1) and senescence-accelerated prone mice (SAM-P/8). However, 30 mM KCl-induced L-[3H]NA release significantly diminished in SAM-P/8 from 3 to 12 months without changing in SAM-R/1. In addition, NMDA-induced L-[3H]NA release was also reduced at 3 months and lowered to a level of spontaneous release at 12 months in SAM-P/8, but no age-related changes in SAM-R/1 were observed. It is suggested that NA release from NA nerve terminals responsive to depolarization is reduced in SAM-P/8 at an earlier stage than in SAM-R/1. Furthermore, NMDA receptors which could be localized in the soma and/or nerve terminals, seem to be involved in NA release and to be decreased with advancing age in SAM-P/8.

Ligand-binding characteristics of [3H]QNB, [3H]prazosin, [3H]rauwolscine, [3H]TCP and [3H]nitrendipine to cerebral cortical and hippocampal membranes of senescence accelerated mouse

The senescence accelerated mouse (SAM) is known as a murine model of aging and memory dysfunction. In the cerebral cortical membranes of male 9-month-old SAM mice, the Bmax values of [3H]rauwolscine and [3H]nitrendipine binding, and the values of both Kd and Bmax of [3H]TCP binding in the accelerated aging strain SAM-P/8, were significantly increased compared with the values in the control strain SAM-R/1. In hippocampal membranes, however, the Bmax values of [3H]quinuclidinyl benzilate and [3H]nitrendipine binding were significantly decreased in SAM-P/8 compared with those in SAM-R/1. These results suggest that muscarinic acetylcholine receptors, alpha 2-adrenoceptors, N-methyl-D-aspartate receptor channels and L-type Ca2+ channels are changed in cerebral cortex and hippocampus in SAM-P/8 at 9 months.

Evidence for the involvement of opioid neuropeptides in the adherence and migration of immunocompetent invertebrate hemocytes

Evidence for the participation of opioid neuropeptides in immunoregulatory activities, especially cellular adherence and migration, has been obtained in representatives of two phyla of invertebrates, the mollusc Mytilus edulis and the insect Leucophaea maderae. The injection of a synthetic analog of [Met]enkephalin [( D-Ala2,Met5]enkephalinamide, DAMA; 10(-6) M) had a stimulatory, naloxone-reversible effect on the directed migration of immunocompetent hemocytes. Incubation of hemolymph in the presence of exogenous or endogenous opioid material significantly enhanced the adherence of hemocytes on albumin-coated slides as demonstrated by use of indirect Zeiss-Zonax reflectance computer analysis. Conversely, hemocyte adherence was markedly reduced by the addition of naloxone (10(-8) M) to the incubation medium, either alone or in combination with DAMA. The antagonistic effects of naloxone on the stimulatory activities of opioids indicate that, like those previously reported in mammals, they are receptor-mediated. The presence of an endogenous [Met]enkephalin-like material was demonstrated in cell-free hemolymph as well as sequestered hemocytes by use of high-pressure liquid chromatography and radioimmunoassay. These results demonstrate that the capacity of immunocytes to release and respond to opioid neuropeptide messengers is not restricted to mammalian organisms but was developed early in the course of evolution.

High affinity dopamine binding to mouse thymocytes and Mytilus edulis (Bivalvia) hemocytes

The present report demonstrates that both mouse thymocytes and Mytilus edulis hemocytes contain a novel type of dopamine receptor. Scatchard analysis of these data revealed a single class of high-affinity binding sites with an affinity constant (Kd) of 6.6 nM, and a binding site density (Bmax) of 141 pmol/g protein in mice and a Kd of 7.6 nM and a Bmax of 66 pmol/g protein for the hemocytes. In older Mytilus the Kd was the same; however, there was a significant decrease in the Bmax (48 pmol/g protein; P greater than 0.05). Age changes were not evident for the mouse cells. The ability of a variety of other related drugs to displace specifically bound dopamine was investigated. The catecholamines (norepinephrine greater than epinephrine) and the dopamine agonist epinine were the most potent of the ligands tested and apomorphine and butaclamol were of moderate potency. This may serve to indicate that this dopamine binding site may be very different from the known D1 and D2 sites. This particular site may represent a third type of dopaminergic receptor. Furthermore, the hemocytes of Mytilus appear to be of two major types, namely, cells with a granular cytoplasm and those whose cytoplasm is agranular. Histofluorescence studies on the hemocytes reveal that a subpopulation of the granule-containing cells appears to contain serotonin.

Occupational health of working women in China

This paper is a review of occupational health of working women in China over the past 37 years. Only four papers in connection with the subject of occupational health for working women published before liberation could be found, in which only 543 female workers were surveyed. Since liberation, 317 papers on the subject have been published, Involving 934, 177 female workers. Owing to tradition and the physiological features women are endowed with, they have a heavy load; what is usually known in China as the ‘double burden'. That is to say, women are not only taking care of household duties but also bearing children.

This paper summarises some major occupational hazards Chinese working women are exposed to, such as chemical, physical, and biological agents and their effects. It also lists certain effective preventative measures now being taken in China.

[Interaction of human embryo cells derived from different tissues with lymphoblastoid cell lines]

Cells from skin and muscle of two month human embryo and from nasopharynx, tonsil, lung and kidney of four month human embryo were cocultivated with lymphoblastoid cells--B95-8 and Raji. It is found that all the epithelial cells, such as the focal growth of epithelioid cells from the tonsil and nasopharynx as well as kidney cells from the human embryo can not adhere to any kind of lymphoblastoid cells; but fibroblasts from muscle and skin of two month embryo or from nasopharynx, tonsil and lung of four month embryo have the ability of sticking to lymphoblastoid cells. However, only the fibroblastoid cells from the nasopharynx of human embryo have the ability to stick and to fuse with lymphoblastoid cells--B95-8 in cocultivation and to activate the EBV production. The mechanism of this phenomenon and its biological functions will be studied in detail.

Threonine kinetics at graded threonine intakes in young men

A study was undertaken in eight healthy young men to examine the effects of varying intakes of threonine on plasma free threonine concentrations and threonine kinetics, using a 3 h constant intravenous infusion of L-[1-13C]threonine. Subjects consumed diets based on an L-amino acid mixture, in which the quality of threonine was reduced every 7 days. On the last day of each diet period, determinations of plasma threonine flux and threonine oxidation were carried out while subjects consumed small meals, each supplying 1/12 daily intake, at hourly intervals. Threonine oxidation rates fell with reduced threonine intake, reaching a relatively constant level at intakes of 20 mg.kg-1.day-1 and below. These metabolic data are discussed in relation to the currently established value of 7 mg.kg-1.day-1 as the upper range of the threonine requirement for healthy young adults. It is concluded that actual threonine requirements may be considerably higher for this age group.

Photosensitization of mitochondrial adenosine-triphosphatase and adenylate kinase by hematoporphyrin derivative in vitro

Mitochondrial ATPase and adenylate kinase activity of hepatoma cells were inhibited by hematoporphyrin derivative (HPD) followed by photoirradiation. Inhibition of ATPase activity was a dose- and time-related event. Malonaldehyde (MDA) content of mitochondrial membranes was markedly increased by HPD plus light. The content of mouse liver microsomal cytochrome P-450 was greatly increased after intraperitoneal injection of HPD for 4 days (5 mg/kg/day). The liver weight, and levels of liver microsomal G-6-phosphatase, MDA and triglyceride (TG) showed no difference in treated vs. control animals. The data presented here demonstrate that mitochondria may be a sensitive site of action of HPD photosensitization, and inactivation of ATPase and adenylate kinase may be an important contributing factor to tumor cell damage and death.

Glucose and insulin effects on the novo amino acid synthesis in young men: studies with stable isotope labeled alanine, glycine, leucine, and lysine

We have explored interrelationships between te dynamic aspects of whole body glucose and alanine and glycine metabolism in adult humans. Using a primed, continuous intravenous infusion of [1-13C] leucine or lysine given simultaneously with [2H3] or [15N]alanine or [15N]glycine, respectively, whole body alanine and glycine fluxes and their rates of de novo synthesis were determined in three experiments with healthy young men. Subjects were studied in the post-absorptive state and during a 150 min period of an intravenous infusion with unlabeled glucose, at a rate of 4 mg.kg-1 min-1. In one experiment, insulin was given together with the glucose infusion to maintain normoglycemia. In the other two studies, subjects received glucose alone. For the post-absorptive state, alanine flux (mean +/- SEM) was 381 +/- 26 and 317 +/- 18 mumole.kg-1 hr-1 in two separate experiments and glycine flux was 240 +/- 22 mumole.kg-1 hr-1. De novo synthesis of alanine and glycine accounted for 75%-81% and 81% of flux, respectively. Infusion with glucose alone raised plasma glucose to a mean level of 152 mg/dl and increased alanine flux, due to a rise in alanine synthesis of 98 mumole.kg-1 hr-1 (p less than 0.01). Glycine flux and synthesis rate were unaffected by the glucose infusion. When insulin was given with glucose to maintain normoglycemia, the rate of alanine synthesis was unchanged. Because glucose uptake rate, measured with [6,6-2H2] glucose was the same whether glucose was infused along or with exogenous insulin, these results support the view that the circulating plasma glucose level itself may affect alanine synthesis and that the hyperglycemic state is an important factor in regulating interorgan nitrogen transfer, via alanine, in various pathophysiologic states.

Quantitative aspects of glucose production and metabolism in healthy elderly subjects

The metabolic basis for the reduced glucose tolerance that occurs during aging in humans has been explored with the aid of a primed constant intravenous infusion method of labeled glucose (6-3H; 6,6,2H- and U-13C-glucose). Healthy young adult men and women (24 +/- 3 yr) and elderly men and women (75 +/- 4 yr) participated in a series of studies designed to quantify rates of plasma glucose appearance, oxidation, and recycling while subjects were in the postabsorptive (basal) state and to determine rates of hepatic glucose production and glucose disappearance in response to intravenous glucose at approximately 1 and 2 mg x kg-1min-1 and also 4 mg x kg-1min-1 without or with a simultaneous infusion of insulin to maintain normoglycemia. Basal rates of glucose production were 2.41 +/- 0.06 and 2.18 /+/- 0.05 mg x kg-1min-1 in the young adults and elderly, respectively (P less than 0.05). Recycling of glucose carbon and glucose oxidation rates did not differ significantly between the two age groups. Infusion of unlabeled glucose reduced hepatic glucose production to the same extent in the two groups, indicating that the mechanisms responsible for altered hepatic glucose production with intravenous glucose administration remain intact during human aging. Plasma insulin changes were similar in young adult and elderly subjects receiving 4 mg x kg-1min-1 unlabeled glucose except that the higher plasma glucose levels in the elderly were associated with higher insulin levels. For elderly subjects, the amount of exogenous insulin required to maintain normoglycemia at the 4 mg x kg-1min-1 glucose infusion rate was about twice that necessary in young adults.