Cholesterol synthesis in freshly isolated human leukocytes

Summary Cholesterol synthesis has been studied in human leukocytes shortly after the isolation from healthy subjects. Not delipidated human serum reduced the cholesterol synthesis when added to the incubation medium. A similar effect was obtained when the leukocytes were incubated in the presence of physiological concentrations of low density lipoproteins.     

Cholesterol synthesis in freshly isolated human leukocytes.

Cholesterol synthesis has been studied in human leukocytes shortly after the isolation from healthy subjects. Not delipidated human serum reduced the cholesterol synthesis when added to the incubation medium. A similar effect was obtained when the leukocytes were incubated in the presence of physiological concentrations of low density lipoproteins.     

Mitogenic activity of selenoorganic compounds in human peripheral blood leukocytes

A variety of organoselenium compounds were originally described as antiinflammatory, antioxidant or glutathione-peroxidase-like agents, and as inhibitors of prostaglandin and leukotriene synthesis. Recently, the compounds have also been found to be inducers of interferon gamma and tumor necrosis factor in human peripheral blood leukocytes (PBL). We evaluated the effects of bis [2-(N-phenylcarboxamido)phenyl] diselenide and Ebselen; 2-phenyl-1,2-benzisoselenazol-3(2H)one, on the incorporation of tritiated thymidine into the DNA of PBL cultured in vitro. Both compounds were mitogenic and this effect was correlated with the expression of interleukin 2 receptor in T-lymphocytes. Therefore, we suggest that the selenoorganic compounds may induce mitogenic cytokines.     

Different methotrexate effects in cultured normal and leukaemic human leukocytes

Summary Evidence is presented that the use of 2 different culture media, with or without methionine, can help to distinguish between normal and leukaemic methotrexate (MTX)-sensitive cells derived from chronic myeloid leukaemia patients. During the blast crisis MTX assays may help directly in the diagnostics of lymphoid involvement.This work was supported by the Polish Academy of Sciences within the project 09.7.4.1.4.Acknowledgments. We are indebted to Prof. Zofia Zieliska, Dept. of Cell Biochemistry, M. Nencki Institute of Experimental Biology PAN for providing the 5-methyltetrahydrofolate and for advice in these studies.     

Mitogenic activity of selenoorganic compounds in human peripheral blood leukocytes

Summary A variety of organoselenium compounds were originally described as antiinflammatory, antioxidant or glutathione-peroxidase-like agents, and as inhibitors of prostaglandin and leukotriene synthesis. Recently, the compounds have also been found to be inducers of interferon gamma and tumor necrosis factor in human peripheral blood leukocytes (PBL). We evaluated the effects of bis [2-(N-phenylcarboxamido)phenyl] diselenide and Ebselen^®; 2-phenyl-1,2-benzisoselenazol-3(2H)one, on the incorporation of tritiated thymidine into the DNA of PBL cultured in vitro. Both compounds were mitogenic and this effect was correlated with the expression of interleukin 2 receptor in T-lymphocytes. Therefore, we suggest that the selenoorganic compounds may induce mitogenic cytokines.     

An improved method for the isolation of eosinophilic leukocytes from normal human blood

Summary A relatively short and simple method for the isolation of the eosinophils from normal human blood is reported. With a recovery of about 45–55%, cell preparations, showing a degree of purity of 90–98%, are obtained. The isolated cells are morphologically intact and viable, as assessed by the trypan blue exclusion test and by active phagocytosis.The authors are indebted to the Schweizerischer National-fonds zur Förderung der wissenschaftlichen Forschung for financial support.     

Internalization of triiodothyronine-bovine serum albumin-colloidal gold complexes in human peripheral leukocytes

Complexes of triiodothyronine-bovine serum albumin-colloidal gold were specifically internalized in human peripheral leukocytes after 5 min of incubation. The specificity was partially lost after a longer incubation.     

In vitro response of human leukocytes to anti-human-thymocyte globulin

Résumé La faculté qu'ont le sérum (ALS) antithymocyte du cheval et son dérivé IgG (ALG) de stimuler la synthèse du DNA avec les leukocytes péripheriques humains a été contrôlée in vitro. Sauf déviation même faible de dosage, l'ALS et l'ALG stimulent la synthèse du DNA. Une forte concentration de ALG inhibe l'effet stimulant de la phytohémagglutinine. Cela peut contribuer en partie à la mort de la cellule ou à sa dégradation à cause de la grande concentration de l'ALS ou de l'ALG.     

The demonstration of D (Rh) antigen in human leukocytes

Zusammenfassung Mit indirekter Fluoreszenz-Antik?rper-Methode wurde nachgewiesen, dass Leukozyten Rh-positiver Versuchspersonen D-Antigen enthalten.      

Internalization of triiodothyronine-bovine serum albumin-colloidal gold complexes in human peripheral leukocytes

Summary Complexes of triiodothyronine-bovine serum albumin-colloidal gold were specifically internalized in human peripheral leukocytes after 5 min of incubation. The specifity was partially lost after a longer incubation.     

On the mechanism of killing ofTrypanosoma cruzi by human polymorphonuclear leukocytes

Summary The temperature-dependence of some processes involved in the killing of sensitizedT. cruzi epimastigotes by human polymorphonuclear leukocytes (PMN) was determined. The rate of the reactions was related to the temperature of incubation according to the Arrhenius equation and the apparent energies of activation (Ea) were calculated. The Ea values separated these complex reactions into two groups: one with Ea of about 10 kcal/mol for the phagocytosis of the parasites and the release of lysosomal enzymes by PMN, and the other with Ea of about 22 kcal/mol for the cytotoxicity against sensitizedT. cruzi, the rate of oxygen consumption by PMN, and the lysis of the parasites with added hydrogen peroxide.This work was supported by research grants from CONICET and SUBCYT, Argentina, and UNDP/Word Bank/WHO Special Programme for Research and Training in Tropical Diseases. The author wish to thank Dr I. Reisin, Dr. A. Boveris and Dr M.M.E. de Bracco for their helpful discussion.     

Etamsylate as inhibitor of prostaglandin biosynthesis in pregnant human myometrium in vitro

Summary The effects of etamsylate on prostaglandin (PG) biosynthesis in microsomes of pregnant human myometrium in vitro have been determined, and compared with those of indomethacin. Both drugs inhibited PG biosynthesis, indomethacin being the more potent inhibitor of the two. Etamsylate inhibited synthesis of 6-oxo-PGF₁, PGF₂, PGE₂, and thromboxane B₂; increasing the concentration of etamsylate increased the inhibition of synthesis. It is suggested that etamsylate has no anti-cyclo-oxygenase activity, but acts by inhibiting the activity of prostacyclin synthetase, endoperoxide reductase, endoperoxide isomerase, and thromboxane synthetase.     

Synthesis and stereospecific synthesis of some alkyl-5-amino-1-glycofuranosyl imidazole-4-carboxylates related to intermediates in purine nucleotide de novo biosynthesis

Zusammenfassung 5-Amino-Glycofuranosylimidazol-Derivative wurden durch Kondensation der Isopropylidenglycofuranosylamine mit Äthyl-N-(Cyano-N-Äthoxycarbonylmethyl)formimidat oder durch Reaktion von Äthylformimidat-Hydrochlorid mit den Furanosylaminen, wozu Äthyl--amino--cyanoacetat hinzugefügt wurde, dargestellt. Bei den Ribose- und Mannosederivaten, wurden - und -Formen als Kristalle isoliert. Eine neue stereospezifische Synthese von Xylofuranosylaminoimidazol über ein Xyloseoxazolin wird beschrieben.