Differences in phagocytic activity of methacrylate copolymer particles in normal and stimulated macrophages

Summary Methacrylate copolymer particles were found to be optimal for a study of phagocytosis in normal and stimulated macrophages, and, after their simple coating with antiserum, for a specific cell labelling with minimal spontaneous adhesion to the cell surface.     

Constituents ofCannabis sativa L. XXI: Estrogenic activity of a non-cannabinoid constituent

Summary A non-cannabinoid phenol (4,4,dihydroxy-5-methoxybibenzyl) increased uterine weight in prepubescent female rats, suggesting non-cannabinoids contribute to the estrogenic effects ofCannabis.Acknowledgments. This research was supported by Contract 271-78-3527 from the National Institute on Drug Abuse and by the Research Institute of Pharmaceutical Sciences, University of Mississippi. The authors are grateful to Karen S. Tomaszewski for technical assistance.     

Influence of adult food on the reproduction of virgin females of anAcanthoscelides obtectus strain originating from Colombian altiplanos

Summary The reproductive activity of virgin females of anAcanthoscelides obtectus strain originating from the high Colombian plateau was variable. Some females did not synthesize vitellogenin during imaginal life while others produced mature oocytes. In the case of virgin females without reproductive activity, the supply of pollen in the adult diet did not stimulate synthesis and incorporation of vitellogenin. On the other hand, the supply of pollen always induced a higher vitellogenin titre in the haemolymph of females which produced oocytes, and stimulated ovarian production.     

Biotin-binding proteins in eggs of oviparous vertebrates

Summary Biotin-binding was found in the egg whites and yolks of all 23 avian species studied, and in a turtle, but the amount varied considerably even in related species. There was no clear correlation in biotin-binding between egg white and yolk in various species. Antigenic determinants of avidin in different species have changed in the course of evolution as compared with those of chicken egg white avidin.We thank Mr Jukka Peltonen and Mr Antti Karlin for the collection of the avian eggs with permission obtained from the Ministry of Agriculture, and Mr Reino Saarinen for the turtle eggs. The authors are indebted to Mrs Outi Kurronen Miss Riitta Mero and Miss Tiina-Maija Mattila for technical assistance. This work was supported by the Ford Foundation Grants No. 760-0526 and No. 790-0665.     

In vitro associations of tomato plants andRhizobium; induction of nitrogenase activity

Summary In vitro associations of the non-legumeLycopersicum esculentum andRhizobium sp. cowpea 32H1 were established. Tomato plants induced rhizobial nitrogenase activity. Induction of nitrogenase activity was possible through a membrane which was impermeable for bacteria.     

Role of lactone ring of aflatoxin B1 in toxicity and mutagenicity

Summary Cleavage of the lactone ring of aflatoxin B₁ results in a nonfluorescent compound that has greatly reduced biological activity. Mutagenicity, as measured by the Ames test, is reduced 450-fold compared to that of B₁, and toxicity, as measured by the chick embryo test, is reduced 18-fold.     

Inhibition of cytosolic rat hepatic glutathione S-transferase activities by bromosulfophthaleins

Summary The enzymatically catalyzed conjugation of glutathione with 1-chloro-2,4-dinitrobenzene and styrene-7,8-oxide is inhibited by tetrabromosulfophthalein in a non-competetive way, although tetrabromosulfophthalein itself is a substrate for glutathione S-transferases. Dibromosulfophthalein, which is not a substrate for glutathione S-transferases, inhibits the 1-chloro-2,4-dinitrobenzene conjugation competetively and the styrene-7,8-oxide conjugation non-competetively.     

A simple method of obtaining multiple blood samples from the portal vein and the hepatic vein in the rat in vivo

A very simple and rapid technique for inserting a catheter in the portal vein and the hepatic vein in the anesthesized rat in vivo is described. The pointed, saline-containing PE tubing is frozen in liquid nitrogen, whereupon it is used as a 'needle' to insert the catheter into the blood vessel. Multiple blood samples can be obtained from the portal and the hepatic vein at the same time, so that in situ extraction of drugs by the liver can be measured in vivo, since hepatic blood flow is uninterrupted.