Captopril (SQ 14,225): In vitro and in vivo influence on the proliferative response of rat lymphocytes

Summary Captopril in vitro (50–500 g/ml) increased³H-TdR incorporation in unstimulated and mitogen-stimulated cultures of rat lymphocytes. Unseparated spleen and lymph node cells of rats orally treated with captopril (50 mg/kg/day×4) showed decreased basal and mitogen stimulated³H-TdR incorporation. The removal of macrophages abrogated this inhibitory effect. Leucine aminopeptidase activity of macrophages was reduced — in vivo and in vitro — by captopril.Acknowledgments. The authors thank the Squibb Institute for Medical Research for the gift of Captopril. The excellent technical assistance of Ms B. Hasselriis, Ms B. Rumler and Ms E. Greve Petersen is gratefully acknowledged.     

Identification of an acyclic diterpene alcohol in the defense secretion of soldiers ofReticulitermes lucifugus

Summary The defense secretion of soldiers ofReticulitermes lucifugus has been shown to contain, predominantly, (R)-(–)-(E,E)-geranyllinalool together with germacrene A and -farnesene.This report covers part of a collaborative study with J.-L. Clément, Lab. d'Evolution, Université P. et M. Curie, Paris, to whom we are grateful for supplies of material and discussions. We also thank Dr O.T. Jones for collections ofReticulitermes lucifugus.     

Genetic polymorphisms and intrauterine development. Evidence of decreased heterozygosity in light-for-dates human newborn babies

Summary In 2 independent samples of low-birth-weight infants the proportion of females and homozygotes for a series of polymorphic systems was higher in light-for-dates than in preterm babies. The observation seems to give support to the hypothesis that homozygosity for normal polymorphisms may decrease in general intrauterine growth rate. Since it is known that survival rate is strongly related to birth weight, a correlation between growth retardation and homozygosity may have a major role in the maintenance of such polimorphisms.We thank Prof. L. Ginzburg for helpful comments.     

Production and detection of antibody against estradiol receptor in the calf uterus. Interaction with the estrogen receptor from the hen oviduct]

The antibodies against estrogen receptor were obtained after injecting Rabbits with a cytoplasmic receptor fraction isolated from Calf uterus. The estrogen receptor was partially proteolysed by the action of trypsin and subsequently purified by affinity chromatography (purification 4,000 to 10,000 fold, to a purity of 5-20%). The affinity of the antibody for the proteolysed receptor is KD approximately 1 nM and serum titres have reached values of approximately 50 nM. The values remained constant after the third injection. Preliminary results indicate that the antibody has approximately the same affinity for "native" cytoplasmic estrogen receptor from Calf uterus, as well as for the "trypsinized" forms of estrogen receptor isolated from Calf uterine cytosol and Hen oviduct nuclei.     

Comparative study, in the Allium test, of the cytotoxicity of tubulosine and of 6 synthetized pseudo-tubulosines]

Comparing cytotoxicity of tubulosine and of six newly synthesized pseudo-tubulosines in the Allium test, we have characterized all the current features of protein inhibition. Nevertheless cytotoxicity of the six pseudotubulosines is much weaker. Furthermore, "floating poles anaphasis", a disturbance characteristic of the action of tubulosine, has been found with a lesser intensity with the other compounds.     

Alkaline phosphatase in human lymphocyte subpopulations.

The levels of membrane alkaline phosphatase have been measured on different lymphocyte fractions from human peripheral blood separated on bovine serum albumin discontinuous gradients. The peak in enzyme activity was observed in a non-T-, non-B-cell fraction, rich in "null" lymphocytes; the lowest values were found in the fraction with the highest proportion of T-cells.     

The effects of physostigmine on the oxygen uptake in rat brain tissue

Summary Physostigmine in a dose of 0.1 mg/kg i.v. expressly stimulated the oxygen uptake in the rat cerebral cortex. This effect was blocked by propranolol and seems be mediated by catecholamines. Since atropine also antagonized the stimulant effect of physostigmine, it appears that the action of physostigmine is primarily cholinergic and that the adrenergic effect is a secondary phenomenon. The higher dose of physostigmine (0.4 mg/kg i.v.) caused a depression of rat brain oxygen uptake.This work was supported by a grant from Serbian Republic Scientific Fund (ZMNU SR Srbija), Belgrade (Yugoslavia).The authors wish to acknowledge the skilful technical assistance of Lj. Krsti.     

Alterations of beta-adrenoceptor-density and cAMP-synthesis in rat-erythrocytes after stress erythropoiesis.

During the maturation of red blood cells from rats after stress erythropoiesis, adenyl cyclase activity and beta-adrenoceptor density (pmoles/mg protein) decrease at distinctly different rates suggesting a different turnover of these membrane units.     

Increase in Na+, K+ -ATPase enzyme units in liver and kidneys from essential fatty acid deficient rats.

(3H)-Ouabain binding to liver and kidney preparations was utilized to estimate the number of Na+, K+-ATPase enzyme units in livers and kidneys from rats fed 2% corn oil supplemented or fat-free diets. The specific (3H)-ouabain binding in liver and kidney preparations from fatty acid deficient rats was increased approximately 40%, but the affinity of the binding sites for ouabain (Kd-value) remained unchanged. The increased concentration of Na+, K+-ATPase enzyme units observed in the essential fatty acid deficient rats may contribute to the reduced body fat accumulation and elevated heat production observed in these animals.     

The detection of superoxide anion from the reaction of oxyhemoglobin and phenylhydrazine using EPR spectroscopy

Summary The low temperature EPR spectrum of a quickly reacted mixture of oxyhemoglobin and phenylhydrazine was studied. With the use of a computer, the spectral contribution of methemoglobin in the region of g=2 was subtracted. The remaining spectrum was that of an axial free radical (g=2.00, g=2.06) having the magnetic parameters of superoxide anion. In the presence of superoxide dismutase, this axial radical was not seen, confirming that superoxide anion is indeed generated by the reaction.The portion of this investigation carried out at the Albert Einstein College of Medicine was supported in part by US Public Health Service Research Grant HL-93399 from the Heart and Lung Institute and by National Institute Contract Nol-CP-55606 to J.P. This is communication No. 378 from the Joan and Lester Avnet Institute of Molecular Biology.Predoctoral fellow in the Medical Scientist Training Program (United States Public Health Service Grant 5-TO-5-GM 01669-12) at the New York University School of Medicine.Recipient of a grant-in-aid from the New York Heart Association.