Dissoziation des mikrosomalen arylamidase-alkalischen phosphatase-komplexes aus rattennieren

The high molecular weight arylamidase-alkaline phosphatase-complex from rat kidney microsomes [1] was carefully dissociated by means of treatment with several hydrolytic enzymes or by acidification. Trypsin, chymotrypsin and pronase cause a selective solubilization of the enzymes discernible at their different electrophoretic mobility in polyacrylamide gel. The lower migrating zone represents phosphatase, the faster migrating zone shows arylamidase activity (molecular weights 180,000 and 172,000, respectively). Incubation of the complex with papain, lipase, neuraminidase or hyaluronidase and incubation at acid conditions (pH optimum 5.0) in the absence of any enzyme also yields in the appearance of two protein bands. In contrast to the alkaline hydrolases the acid hydrolases, the pH 5-treatment and with a certain degree also the lipase liberate a second arylamidase zone lying in the phosphatese containing zone during polyacrylamide gel electrophoresis. Treatment with SDS and subsequent SDS-polyacrylamide gel electrophoresis also results in a dissociation of the complex, but only in one protein fragement (approx, molecular weight 205,000).

Effect of amphetamines on tryptophan concentrations in mice and rats

(±)-Amphetamine and some of its analogues were administered intraperitoneally to mice and rats and the concentrations of tryptophan in tissues were analysed by fluorimetric and microbiologic techniques. The concentration of tryptophan in brain was markedly increased by (±)-amphetamine and reached a maximum about 80 min after drug administration. The effect was dose-dependent with a threshold dose below 1 mg/kg. (+)-Amphetamine was significantly more potent than p-chloroamphetamine and p-hydroxyamphetamine, indicating that the changes in tryptophan concentrations might be related to the central stimulating effect of the drugs. (±)-Amphetamine delayed the disappearance from brain of intravenously administered [3H]tryptophan. Inhibition of monoamine oxidase by nialamide (100 mg/kg) and tryptophan hydroxylase by H 22/54 (500 mg/kg) had no effect on the tryptophan concentration in brain.

Mutagenicity and cytotoxicity of irradiated foods and food components

The preservation of foods by treatment with ionizing radiation can significantly increase the world's food resources by reducing spoilage and waste. However, irradiation can bring about chemical transformations in food and food components resulting in the formation of potential mutagens, particularly hydrogen peroxide and various organic peroxides. In order to evaluate the safety of irradiated foods for general consumption by the public, and, indeed, the safety of all foods subjected to environmental factors such as food additives, pesticides, drugs, air and water pollutants, etc., it is necessary to supplement the usual feeding tests with procedures designed to detect all classes of genetic damage. This article includes a comprehensive critical review of (1) the experimental evidence relating to the presence of mutagenic and cytotoxic agents in irradiated media, as detected by their effects on mammalian and non-mammalian cells; (2) the chemical changes produced in irradiated media, especially those which produce known mutagenic substances; and (3) new and convenient in vivo methods for the detection and evaluation of genetic damage in mammals.

Radiation of hemocyanin: inactivation and reactivation of oxygen-carrying capacity

Oxygen-carrying capacity of hemocyanin from Limulus and Busycotypus (Busycon) decreases with increasing radiation, giving initial yield values for G(-O(2),) of 1.1 and 1.0, respectively. High radiation doses regenerate this capacity of Busycotypus hemocyanin. These effects are attributed largely to the dual nature of hydrogen peroxide, which, at low concentrations, oxidizes protein-bound copper and at high concentrations, that is, at high doses, reduces oxidized copper. The ability of hemocyanin to decompose hydrogen peroxide is relatively unaffected by irradiation, which suggests that copper atoms at the active sites are not all equivalent. The catalase-like activity of Busycotypus hemocyanin can be simulated by amino acid chelates of copper, including arginine, histidine, and glycine.

Clinical and Scintigraphic Findings in Radiation Myositis Complicating the Intraperitoneal Administration of 198Au

Praeperitoneal administration of colloidal 198Au complicating the treatment of anascitic ovarian cancer is reported. Typical scintiscans and various clinical findings of muscle necrosis and radiation myositis are described. Administration of larger amount of saline solution preceding the radiogold instillation controlled by simultaneous scintiscanning are suggested as safety measures in patients when no ascitic fluid is present.