Spectral changes resulting from the interaction of some N-alkyl nitrosamines and rat liver microsomes

Summary Dimethyl (DMN) and diethyl nitrosamine (DEN) do not give characteristic spectral changes upon interaction with rat liver microsomes, while dipropyl (DPN) and dibutyl (DBN) nitrosamine cause type I spectral changes. The spectral binding constant is 100 mM for DPN and 1.17 mM for DBN. The maximal spectral change is 3.2×10⁶ and 1.0×10⁶ absorbance units per milligram protein for DPN and DBN respectively.Acknowledgment. This work was supported by Grants AM 13195-07 from the National Institute of Health (USA) and from the Consejo Nacional de Investigaciones Cientificas y Técnicas (Argentina).     

The localization of kallikrein in the dog and guinea-pig submandibular glands

Summary In the dog and guinea-pig submandibular glands kallikrein seems to be present in the striated duct cells. Following sympathetic nerve and in vivo isoproterenol stimulation of the dog and guinea-pig submandibular gland respectively, there is a reduction of kallikrein concentration. Ultrastructurally this reduction corresponds to the decrease of straited duct secretory granules in both species. Parasympathetic stimulation also causes some release of kallikrein from both species.Supported by Dean's M.R.C. grant to the College of Dentistry.     

Comparison of chemiluminescence and absorptiometry in enzyme immunoassays for protein quantification

The use of chemiluminescence in competitive binding assays for human serum albumin, human alpha-fetoprotein and human immunoglobulin G and in double antibody sandwich enzyme immunoassays for cytomegalovirus and herpes simplex virus increased the sensitivity of the detection of antigen or antibody 16- to 95-fold above that obtained by conventional absorptiometric methods.     

Brain chopping: A new method for the rapid removal of newborn rat brain

Summary A new multi-bladed air-driven guillotine is described. This device removes newborn rat heads and slices them into several thin wafers, which facilitates freezing and permits easy regional dissection.Supp. in part by U. S. Public Health Service Grant. AA-01391.     

The effect of oxine-5-sulphonic acid on the hepatic drug metabolism in the rat

Summary Oxine-5-sulphonic acid inhibits the metabolism of aminopyrine in the rat liver in vitro. The characteristics of this inhibition vary according to whether the oxidativeN-demethylation of the substrate is determined by the formation of the metabolite 4-aminoantipyrine or by the production of formaldehyde.