Search PubMed⌕ Search

Biomedical subjects

E F Elstner

Publications and source records attributed to E F Elstner.

113 records · Page 7Linked to original sources
PubMedDate not supplied

Detection of the production of reactive oxygen species by neutrophils in whole blood: modulation by adamantanes and triggering by Fe(3+)-ions.

Using indicators for the production of reactive oxygen species (ROS) such as the a) OH-radical type (alpha-keto-gamma-methiolbutyric acid, KMB) or b) hypochlorous acid (1-amino-cyclopropyl-1-carboxylic acid, ACC) neutrophil activities can be both quantified and differentiated in whole blood via ethene production. Ethene is trapped in the head space of blood samples incubated in the presence of zymosan and the respective indicators, KMB or ACC. This procedure allows the detection of effects of aminoadamantanes (AAD) such as amantadine or memantine, compounds frequently used for the treatment of Morbus Parkinson and Morbus Alzheimer. In this report we describe the detection of OH.-type oxidants produced by isolated activated neutrophils and whole blood. Immunomodulatory activities of AAD are deduced from the following observations: AAD-stimulated ethene formation from (KMB) as an indicator for production of OH.-type reactive oxygen species by zymosan-stimulated neutrophils ("respiratory burst") is detectable with isolated neutrophils. In whole blood, however, this reaction is only measurable in the presence of Fe-EDTA-complex. Stimulating effects of AAD are observed within a concentration range between 10(-8) and 10(-4) M with a maximum at 1 microM. Ethene release from (ACC) as indicator for the myeloperoxidase reaction after degranulation is not stimulated by AAD but inhibited at concentrations higher than 100 microM. The presented results suggest that submicromolar concentrations of AAD only stimulate the respiratory burst and apparently not degranulation of zymosan-prestimulated polymorphonuclear neutrophils (PMN).

Adamantane↗
PubMedDate not supplied

Biological durability and oxidative potential of man-made vitreous fibres as compared to crocidolite asbestos fibres.

In this study we investigated relationships between redox properties and biodurability of crocidolite asbestos fibres and three different man-made vitreous fibres (MMVF): traditional stone wool fibres (MMVF 21), glass fibres (MMVF 11) and refractory ceramic fibres (RCF). Each fibre type was incubated up to 22 weeks in four different incubation media: gamble solution (GS) pH 5.0 and pH 7.4, representing blood plasma without proteins, and surfactant-like solution (SLS) pH 5.0 and pH 7.4. During incubation time aliquots of incubation mixtures were removed and analysed in a biochemical model reaction, mimicking activated phagocytes. In addition, changes of fibre morphology and chemical composition were examined using SEM- and EDX-technology. In the presence of crocidolite asbestos fibres and MMVF 21 the formation of OH*-radicals according to the Haber-Weiss sequence could be demonstrated, whereas MMVF 11 and RCF showed no reactivity. Crocidolite asbestos fibres exhibited a significant higher activity compared with the stone wool fibres at the onset of incubation. The oxidative capacities of these fibre types were shown to depend on both specific surface area and iron content. The oxidative potentials of crocidolite asbestos fibres as well as MMVF 21 were not constant during incubation over several weeks in each incubation medium. The reactivities showed sinoidal curves including reactivities much higher than those at the onset of incubation time. These irregular changes of oxidative capacity may be explained by changes of the redox state of fibre surface-complexed iron. Furthermore our results showed clear differences between incubation of fibres in GS and SLS, respectively, indicating that phospholipids play an important part in fibre dissolution behaviour and oxidative reactivity. In conclusion we suggest, that biodurability testing procedures should not exclusively concentrate on dissolution rates of fibres. They should include fibre characteristics concerning known pathogenic mechanisms to evaluate the real toxic potential of the fibre type looking at. Secondly we suggest, that phospholipids should be constituents of incubation liquids used for standardised fibre biodurability test procedures thus representing more realistic incubation conditions.

Asbestos, Crocidolite↗
PubMedDate not supplied

[Heme activated oxidations using the chlorite-oxygen complex "TCDO" (Oxoferin)--an overview].

Several chlorooxygen compounds, hydrogen peroxide and reducing molecules in the presence of chelated iron (Fenton systems) are oxidants of biological relevance. These compounds are either produced in living tissues or are in use as disinfectants or drugs. Tetrachlorodecaoxide as the active principle in the drug OXOFERIN can be differentiated from the above mentioned oxidants by means of simple biochemical test systems where different activators and detector molecules are used.

Chlorine↗
PubMedDate not supplied

Binding and uptake of 125iodine-labelled, oxidized low density lipoprotein by macrophages: comparison of the effects of alpha-tocopherol, probucol, pyridoxal-5'-phosphate and magnesium-pyridoxal-5'-phosphate-glutamate.

Specific and unspecific binding and uptake (internalization) by macrophages of 125iodine-labelled, copper-oxidized human low density lipoprotein is differently influenced by the anti-oxidants alpha-tocopherol (alpha-Toc), probucol (Prob), pyridoxal-5'-phosphate (PP) and the magnesium-pyridoxal-5'-phosphate glutamate complex (MPPG). Binding as well as internalization, mediated by the so-called "scavenger receptor" is lower in the presence of MPPG whereas both specific binding and internalization are enhanced. The comparison of the effects in vitro allows a rating of the potentially anti-atherogenic and thus protective effects of the tested substances as follows: MPPG > PP > alpha-Toc > Prob.

Animals↗