Generation of volatile hydrocarbons from amino acids and proteins by an iron/ascorbate/GSH system

Incubation of free, but not of peptide-bound methionine in an iron/ascorbate system resulted in ethylene generation, which was inhibited by glutathione. Leucine and isoleucine, however, when incubated in an iron/ascorbate/GSH system, released small amounts of propane and ethane, respectively. Peptide-bound leucine additionally yielded butane, as did bovine serum albumin or casein. Hydrocarbon generation from amino acids was inhibited by hydroxyl radical scavengers, but catalase and superoxide dismutase were more efficient. Additionally, ethane and propane generation in this system was optimal at pH 6.2 suggesting the involvement of protonated superoxide besides OH-radicals which attack the side chains of Leu and Ile and very probably produce carbon-centered radicals, which should abstract a hydrogen atom from the thiol group of GSH resulting in the formation of saturated hydrocarbons.     

Diagnosis of congenital toxoplasmosis by two-dimensional immunoblot differentiation of mother and child immunoglobulin g profiles

Differentiation between the specific immunoglobulin G (IgG) response to Toxoplasma gondii by a mother and her newborn child is helpful in the diagnosis of congenital infection with T. gondii in newborns without T. gondii-specific IgM and/or IgA antibodies at birth. Previous methods include immunoblotting and complexing T. gondii antigen with the sera from the mother and child and comparing the bands after electrophoresis. We developed a two-dimensional immunoblotting (2DIB) method with T. gondii RH strain tachyzoite antigen and validated the method with sera from 11 children identified through the neonatal screening program for congenital toxoplasmosis in Denmark. The children were identified by using Toxoplasma-specific IgM antibodies at the screening test, but the presence of T. gondii-specific IgM and/or IgA antibodies could not be confirmed at the subsequent serum sample tested. The children were monitored for at least 12 months, and in seven of eight patients monitored for 12 months the results of the 2DIB-predicted congenital infection were confirmed by the presence of persistent Toxoplasma-specific IgG antibodies. 2DIB is a sensitive technique that allows early differentiation between passively transferred maternal T. gondii-specific IgG antibodies and antibodies synthesized by the newborn child.     

Molecular aspects of catechol and pyrogallol inhibition of liver microsomal lipid peroxidation stimulated by ferrous ion-ADP-complexes or by carbon tetrachloride

Summary Lipid peroxidation was induced in rat liver microsomes either by iron-ADP-complexes or by carbon tetrachloride in the presence of NADPH. Different compounds containing catechol or pyrogallol structures were examined for their activities to inhibit lipid peroxidation in both systems. In general, all compounds tested showed similar inhibitory activities on lipid peroxidation, if induced by ferrous ion-ADP-complexes or by carbon tetrachloride. This inhibition is explained by the suggestion that catechols and pyrogallos inhibit at the lipid site of the membrane, rather than at the enzymic site. Compounds not containing catechol or pyrogallol groups inhibited lipid peroxidation only weakly. O-Methylation resulted in a decrease of the inhibitory effect. Catecholor pyrogallol-derivatives which contained polar functional side chains, like carboxyl- or amino groups showed minor inhibitory effects compared to the esterified or N-alkylated compounds.Dihydroxychlorpromazine, 2-hydroxy-estradiol and 2-hydroxyethinylestradiol were the most effective inhbitors of microsomal lipid peroxidation (I₅₀-values of 1×10^–6 to 2×10^–7 M). The inhibitory activity of -tocopherol, glutathione and ascorbic acid, naturally occurring antioxidants, was about three orders of magnitude lower.Inhibition of lipid peroxidation induced by NADPH-cytochrome c reductase and iron-ADP-complexes in the presence of NADPH and liposomes was also observed with catechols.From our results we assume that the molecular structure of a catechol or pyrogallol functional group is a prequisite for an effective inhibition of lipid peroxidation by these chemicals. Furthermore, the results are discussed in relation to the requisite membrane affinity of catechols, pyrogallols and other antioxidants which might be used for inhibition studies on lipid peroxidation in vivo.     

The significance of covalent binding of catechols to proteins in vivo

When rats were dosed with 14 g/kg ³H-isoproterenol, ³H-radioactivity was measurable in the liver until 48 h. This amount was not different in livers of animals which have been pretreated with diethyl maleate.After exhaustive extraction, a significant amount of ³H-radioactivity from isoproterenol could be detected in the proteins of total liver (homogenate), of cytosol and of microsomes. In the cytosol fraction of diethyl maleate pretreated animals twice the amount of isoproterenol-radioactivity was found in the extracted proteins compared to controls. In the microsomal fraction there was no difference between diethyl maleate pretreated and control animals in the amount of radioactivity incorporated into proteins.In all fractions the radioactivity measurable in the extracted proteins declined with a half life time of about 24 h.The in vivo results on covalent binding of isoproterenol are compared to the irreversible protein binding of ethinyloestradiol in vivo. Quantitatively, these in vivo data are compared to the results on irreversible protein binding obtained during incubations of isoproterenol or ethinyloestradiol with rat liver microsomes.Presented at the Symposium Influence of Metabolic Activations and Inactivations on Toxic Effects held at the 18th Spring Meeting of the Deutsche Pharmakologische Gesellschaft, Section Toxicology, D-6500 Mainz, March 15, 1977     

Alcohol consumption and hepatic fibrosis affect the fatty acid composition of red blood cells and their susceptibility to lipid peroxidation

Erythrocytes from alcoholics with and without liver cirrhosis and from rats treated either with ethanol or thioacetamide, the latter treatment resulting in hepatic fibrosis, were analysed for their membrane fatty acid composition and their susceptibility to lipid peroxidation. Red cells containing less arachidonic acid than controls, as found in alcoholics with liver cirrhosis, were less susceptible to lipid peroxidation than controls. This observation was confirmed by experiments with rat erythrocytes obtained from animals with hepatic fibrosis. However, red cells containing less linoleic acid than controls, as found in alcoholics without liver cirrhosis, exhibited a normal degree of lipid peroxidation upon oxidant stress induced by hydrogen peroxide. The results demonstrated that in red cells only fatty acids with four double bonds seem to be involved in membrane peroxidation reactions under the condition chosen. This observation might be of relevance for in vivo aging of red cells.Dedicated to Professor Dr. med. Herbert Remmer on the occasion of his 65th birthday     

Providing internet lessons to oncology patients and family members: a shared project

The paper describes the steps in a pilot study taken to develop and evaluate an Internet intervention for cancer patients and family members. The intervention was a shared project of two hospital departments; a volunteer oncology support service, Hope & Cope, and the Health Services Library. Forty subjects were surveyed on their computer use and interest, and of these, half used the Internet to access health and medical information. Of the 40 subjects, 28 participated in an innovative, one-to-one teaching session with a medical librarian where they learned to access Internet sites to find information specific to their needs and subsequently be more confident in their perceived ability to evaluate the information received. Follow up interviews found that the sessions were well received and at two months follow-up the participants attributed their positive well being in large part to the intervention. Internet use by oncology patients and family members in conjunction with skilled help has the potential to contribute in a timely fashion to the well being of those with cancer.     

Zur Standardisierung der Hämoglobinbestimmungen

Ohne Zusammenfassung     

Die Induktion mikrosomaler Enzyme der Rattenleber

Ohne Zusammenfassung     

Die extracorporale Dialyse von Luminal

Ohne Zusammenfassung     

Vermehrte Bildung von endoplasmatischem Reticulum in der Leberzelle unter der Wirkung von Arzneimitteln

Ohne Zusammenfassung