Biomedicine / [publiee pour l'A.A.I.C.I.G.]最新文献

Evidence is presented below that normal human sera contain a potent non-dialyzable factor inducing abundant giant fat cells in human bone marrow culture, normal as well as CML. Media with 20% heated (56 degrees C) human serum induce during 7-14 days almost complete monolayer of fat cells on the bottom of the plastic flasks or dishes. Fetal bovine sera do not exhibit this effect and shift cultures to the proliferation of fibroblasts. We are studying the functions of fat cells in hemopoiesis as well as the biochemical nature of fat cell-inducing factor in human sera.

Conflicting results have been reported on the influence of portacaval anastomosis on liver carcinogenesis. The purpose of this investigation was to study the effect of portal diversion on liver carcinogenesis induced in the rat by a potent chemical liver carcinogen, Aflatoxin B1 (AFB1). Liver tumors appeared earlier and were significantly bigger in rats with shunts than in sham-operated controls. Portal diversion also induced in rats fed AFB1 a splenic atrophy with nearly complete disappearance of Malpighian corpuscles suggesting a profound immunodepression. This might be responsible for the enhancement of liver cancer by portacaval anastomosis in the rats fed AFB1. Thus, the influence of portal diversion on liver cancers appears to be multifactorial.

The rate of red-cell metabolism of pyridoxine to pyridoxal phosphate was measured in control subjects and patients with homozygous and heterozygous beta-thalassaemia from Ferrara, Northern Italy, and in British control subjects of Anglo-Saxon origin. A high incidence of a slow rate of B6 metabolism was found in beta-thalassaemia in Ferrara similar to that found previously in Cypriots living in London. Of particular interest was a much slower rate in control subjects from Ferrara than in British control subjects of Anglo-Saxon origin. The suggestion that a high incidence of a slow red-cell metabolism of B6 is the result of selection by malaria, whether associated with thalassaemia or not, is considered.

The effects of a single oral dose of 2.5 mg bromocriptine on serum level of TSH and prolactin were studied in a group of normal male subjects. Bromocriptine effectively inhibited basal TSH and prolactin concentration as well as the prolactin and TSH response to TRH given 4 hours later. The prior administration of the extracerebral dopamine antagonist domperidone reversed the endocrine effects of bromocriptine. The results suggest that dopamine receptors located at the pituitary may regulate TSH (and prolactin) release in man.

Cellular and humoral immunity was examined in Hodgkin's disease and non Hodgkin lymphoma (33) patients and compared with a normal group. Mixed lymphocyte cultures (MLC) were used as parameter for cell mediated immunity and anti-Epstein Barr virus (EBV) antibodies for specific humoral immunity. High stimulation indices coincided with low anti-VCA and anti-EBNA titers in the control group (r = -0.343). This negative correlation was not found in non Hodgkin lymphomas and was substantially lower (r = -0.142) in Hodgkin's disease. The alterations in immunoregulatory mechanisms in these patients are discussed.

Cell culture media in which the usual serum supplement required for growth has been replaced with specific combinations of hormones, nutrients and purified serum proteins have been developed which allow the growth of a number of human cell types. These media afford particular advantages in terms of simplicity of experimental design for some kinds of experiments. Also, the media may be designed to be selective with regard to cell type, so that fibroblastic overgrowth of primary cultures of epithelial cells can be avoided. Often the proliferative and differentiative responses of cells in vivo are better preserved in vitro in the serum-free media, resulting in new systems in which to study cell differentiation and responses of cells to environmental factors such as hormones.

A comparative study of karyotypes and neutrophil alkaline phosphatase (NAP) was carried out for 70 parents (35 couples) of trisomy 21 children and their 35 trisomy 21 children and for 110 control parents (55 couples) and their normal children. In the trisomy 21 families we found a significant increase in NAP: mother P less than 10-4; father P less than 10-4; children P less than 10-9; the NAP level in affected child is approximately equal to the sum of the NAP levels of the two parents (P = 0.80; sigma2 = 5%). In one parent of a trisomy 21 child, a karyotype anomaly was present.

The intestinal brush-border disaccharidases most resistant to pancreatic protease digestion in vitro are lactase and trehalase. When compared to maltase and sucrase, they are also those which showed the largest increase during development of guinea pig fetuses. These results suggest that pancreatic proteases may play a role in the control of brush-border disaccharidase activities during fetal development.

Treatment of human cultured T cells by interferon (IFN), which enhances cell-mediated cytotoxicity directed against human K562 cell targets (NK-like activity) induces an activation of cell hydrolases. Treatment of mouse cultured L929 cells by IFN and double strand RNA enhancing cell autolysis induces first an activation of tested hydrolases (hexosaminidase, beta-glucuronidase, acid and alkaline phosphatases). Polyenzymatic activation of hydrolases induced by IFN is similar to coordinate enzymatic induction described by Hosli which occurs by lack of specific enzyme when non-digestible substrates are absorbed by cells. It is hypothesized that the polyenzymatic activation which accounts for cell lysis is a general defense mechanism which might also explain other actions related to IFN such as antiviral effect, inhibition of cell division, diminution of protein synthesis and cell surface alteration.