Large-scale purification of hepatitis B surface antigen using affinity chromatography

Summary Large-scale purification of hepatitis B surface antigen, applicable to the preparation of potential vaccines for prevention of hepatitis B, is described. The method involves the following steps: precipitation of serum with polyethylene glycol 6000, affinity chromatography on concanavalin A-Sepharose and on -aminononyl-Sepharose, and isopycnic centrifugation.This study was supported by grant 09011 from the National Heart, Lung and Blood Institute. We thank Dr. B. Hollinger for testing HB_sAg samples by a complement fixation test.     

Interference of sodium ethylenediaminetetraacetate in the determination of proteins and its elimination

Zusammenfassung Es wird die Interferenz von Natrium Ethylendiaminotetraacetat bei der Eiweissbestimmung nach der Methode vonLowry et al. und deren Verhinderung gezeigt. Die Anwesenheit von Natrium Ethylendiaminotetraacetat interferiert bei der Eiweissbestimmung nach der Methode vonLowry, da sie selbst zur Reduktion des Folin-Reagens führt. Es gelingt, diese Interferenz durch Zusatz von CaCl₂ zu verhindern.     

Quantitative determination of adenovirus antigens by means of a fluorescent precipitin test

Zusammenfassung Es wird die Anwendung eines quantitativen Fluoreszenz-Präzipitin-Tests für Adenovirus-Antigene beschrieben. Die Methode wurde für 11 verschiedene Adenoviren angewendet und hat sich als relativ typenspezifisch erwiesen.

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This investigation was supported in part by contract PH43-63-80 from the National Institutes of Health.     

Zur Frage des Vorkommens von N-Nitroso-Verbindungen im Tabakrauch

Summary Important facts in connection with the occurrence of N-Nitroso compounds in tobacco smoke have been summarized. This paper reports on analytical methods for the identification of N-Nitroso compounds. The figures known about nitrate content and volatile bases of tobacco, as well as the nitrogen oxides and volatile bases of tobacco smoke as precursors of N-Nitroso compounds, are summarized. The third order reaction of secondary amines with an equimolar mixture of nitric oxide and nitrogen dioxide is a precondition for the formation of N-Nitroso compounds in tobacco smoke. While examining tobacco smoke for N-Nitroso compounds, temperature and time conditions have to be adapted to the natural smoking process. The use of solvent as well as cold traps has to be avoided to exclude the formation of artifacts. Analyses completed under these conditions furnished results of 0.004µg of a mixture consisting of N-Nitroso-dimethylamine and N-Nitroso-pyrrolidine, calculated as N-NO per cigarette. A number of animalexperimental preconditions are still lacking, to judge the biological effects of these extraordinarily small amounts of N-Nitroso compounds.