Influence of the thymus on the incidence of secondary and parabiotic disease

Summary The secondary disease in PF₁ strain combination depends upon the immune status of both partners. It is most clearly expressed if both donors and recipients are immunologically crippled by thymectomy and irradiation. Conspicuous reduction in the immune potential of parental parabionts induced by thymectomy and irradiation displayed their marked incidence of parabiotic death.     

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.     

Preparation and oxygen binding properties of soluble covalent hemoglobin-dextran conjugates

Summary Stroma-free hemoglobin solutions present some drawbacks when used as blood substitutes, essentially because the hemoprotein has a low vascular retention, due to its small hydrodynamic volume. Covalent coupling of the protein with dextran derivatives artificially increases its size and affords polymeric conjugates whose oxygen-binding properties (Barcroft's curve, Hill coefficient) depend on the molecular weight.The authors wish to thank Prof. J. Neel and Prof. C. Vigneron for useful discussions and criticism.     

Influence of the enteric surface coat on the unidirectional flux of acetamide across the wall of rat small intestine

In vivo treatment of the jejunal mucosa with glycosidic enzymes seems to remove the enteric surface coat of the enterocyte. As a consequence, the mucosa-to-serosa unidirectional flux of acetamide increases remarkably. The glycocalyx probably represents a barrier to the diffusion of small hydrosoluble solutes.     

Cantharidin biosynthesis in a blister beetle: inhibition by 6-fluoromevalonate causes chemical disarmament

Biosynthesis of cantharidin in a blister beetle, Lytta polita, is effectively inhibited by 6-fluoromevalonate. Inhibition is attributed specifically to the fluorine substituent. Biochemical inhibition has not been demonstrated previously for an arthropod's defensive substance.     

Lipoprotein lipase activity in normal human adipose tissue and its absence in human lipomas

Résumé Il a été trouvé que des spécimens de tissus souscutanés humains et des tissus adipeux omentaux hydrolyseraient un substrat triglycéride activé avec du plasma humain quand incubés dans un medium contenant de l'albumine bovine et du sulfate d'ammonium. Les spécimens de lipomes humains n'ont pas montré d'activité lipolytique signifiante. Les homogénates de lipomes n'ont pas diminué l'activité lipolytique des spécimens de tissus adipeux humains.     

Persisting circadian rhythm in hepatic glycogen of mice during inanition and dehydration

Zusammenfassung Eine Circadianrhythmik des Mäuseleberglycogens lässt sich durch Standardisierung anderer biologischer Frequenzen und «Lärm» isolieren. Dies gelingt auch nach Entzug von Futter oder Futter und Wasser. Persistente Rhythmen mit grosser Amplitude kennzeichnen eine Reihe physiologischer Funktionen nach Futter- und Flüssigkeitsentzug und können als Chossatphänomene bezeichnet werden.

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Work supported by the Elsa U. Pardee Foundation, the National Aeronautics and Space Administration of the USA (NsG-517) and the US Public Health Service (5-K6-GM-13).