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Biomedical subjects

E F Elstner

Publications and source records attributed to E F Elstner.

At least 55 records · Page 3Linked to original sources
PubMed1994

Tetrachlorodecaoxygen, a wound healing agent, produces vascular relaxation through hemoglobulin-dependent inactivation of serotonin and norepinephrine.

We investigated the vasoactive actions of the wound-healing agent tetrachlorodecaoxygen (TCDO). TCDO (20 microM) had no direct effect on tone in isolated calf pulmonary arteries precontracted with potassium with or without 1 microM reduced hemoglobin under O2 or N2 atmosphere. However, TCDO, in a reduced hemoglobin-dependent manner, attenuated contraction produced by serotonin, associated with spectral changes consistent with destruction of serotonin. The loss of tone induced by serotonin catalyzed by TCDO plus reduced hemoglobin was not altered in the presence of superoxide dismutase (SOD) plus catalase. TCDO plus reduced hemoglobin also produced rapid relaxation of isolated rabbit aorta precontracted with norepinephrine (NE), whereas with phenylephrine (PE)-induced bone, the observed relaxation was slow to develop. Neither did TCDO, with or without reduced hemoglobin, alter soluble guanylate cyclase activity in pulmonary artery. Thus, a highly reactive species produced by interaction of TCDO with reduced hemoglobin appears to attenuate the contractile actions of serotonin, NE, and PE, selectively potentially by destroying these vasoactive agents. The vasodilator actions of TCDO (plus reduced hemoglobin) may contribute to wound healing by increasing nutrient blood flow and O2 delivery needed for repair processes and bactericidal activity.

Animals↗
PubMed1992

Peroxide-dependent amino acid oxidation and chemiluminescence catalysed by magnesium-pyridoxal phosphate-glutamate complex.

Magnesium-pyridoxal-5'-phosphate-glutamate (MPPG) has been shown to ameliorate atherosclerotic symptoms in rabbits. In vitro, MPPG in the presence of peroxides such as cholesterolhydroperoxide or cumene hydroperoxide and Mn2+ ions produces "excited states" measurable as chemiluminescence or ethylene release from 1-aminocyclopropane-1-carboxylic acid (ACC). The reactions are stimulated synergistically by unsaturated fatty acids. Pyridoxal phosphate exhibits similar properties, but can be differentiated from the activities of MPPG or the sum of the components present in MPPG.

Amino Acids↗
PubMed1992

Oxidative destruction of biomolecules by gasoline engine exhaust products and detoxifying effects of the three-way catalytic converter.

Aqueous solutions of engine exhaust condensation products were derived from cars powered by diesel or four-stroke gasoline engines (with and without three-way catalytic converter). The cars were operated on a static test platform. Samples of the different exhaust solutions accumulated in a Grimmer-type distillation trap (VDI 3872) during standard test programs (Federal Test Procedure) were incubated with important biomolecules. As indicators of reactive oxygen species or oxidative destruction, ascorbic acid, cysteine, glutathione, serum albumin, the enzymes glycerinaldehyde phosphate dehydrogenase and xanthine oxidase, and the oxygen free-radical indicator keto-methylthiobutyrate were used. During and after the incubations, oxygen activation (consumption) and oxidative destruction were determined. Comparison of the oxidative activities of the different types of exhaust condensates clearly showed that the exhaust condensate derived from the four-stroke car equipped with a three-way catalytic converter exhibited by far the lowest oxidative and destructive power.

Antioxidants↗
PubMed1991

Oxygen radicals--biochemical basis for their efficacy.

In the last decade it has become quite clear that oxygen free radicals are involved in a vast amount of diseases such as cataract, atherosclerosis, rheumatism, arthritis, Parkinson's disease, reperfusion injuries and many others. The induction of defence systems against certain stresses (heat shock, inflammation) is also mediated by activated oxygen species. Oxygen-activation and -desactivation has to be regulated and well attenuated in aerobic cells and tissues. The biochemical basis of the biological efficacy of oxidants is thus based on a sophisticated balance between catalysis of production and reactivity of oxygen radicals by certain cofactors and transition metals on the one hand and on a reliable detoxification by antioxidants or metabolic chains on the other hand. In this communication, different oxygen activating principles are compared and the biochemical basis for the induction of repair processes by a synthetic heme oxidant, (Tetrachlorodecaoxide, TCDO) is presented.

Animals↗
PubMed1991

Air pollution: involvement of oxygen radicals (a mini review).

In the past decades air pollution has increased worldwide. We also gained more insight into the complex interactions between different air pollutants in the atmosphere as well as their effects on living cells and organisms. It also has been unequivocally shown by several groups in different countries that oxy radicals play an outstanding role in the interconversion of air pollutants as well as during the manifestation of toxic effects. Not only living systems are affected by air pollutants, but also inorganic systems such as buildings and sculptures. In the following overview the most important reactions occurring in the atmosphere as well as effects of oxidative gaseous compounds and particles such as diesel soot and asbestos will be discussed.

Air Pollutants↗
PubMed1990

Oxidative protein modification as predigestive mechanism of the carnivorous plant Dionaea muscipula: an hypothesis based on in vitro experiments.

Aqueous leaf extracts from Dionaea muscipula contain quinones such as the naphthoquinone plumbagin that couple to different NADH-dependent diaphorases, producing superoxide and hydrogen peroxide upon autoxidation. Upon preincubation of Dionaea extracts with certain diaphorases and NADH in the presence of serumalbumin (SA), subsequent tryptic digestion of SA is facilitated. Since the secretroy glands of Droseracea contain proteases and possibly other degradative enzymes it is suggested that the presence of oxygen-activating redox cofactors in the extracts function as extracellular predigestive oxidants which render membrane-bound proteins of the prey (insects) more susceptible to proteolytic attacks.

Animals↗
PubMed1990

Influence of diesel soot particles and sulfite on functions of polymorphonuclear leukocytes.

Aqueous suspensions of diesel soot particles in combination with sulfite influence certain functions of human polymorphonuclear neutrophils in vitro. Chemiluminescence, generated after activation by opsonized zymosan as well as oxygen uptake were decreased, whereas phagocytosis was increased. An enhancement of degranulation could not be observed. The single substances show little or no effects on the above properties. The results indicate that combinations of air pollutants such as diesel soot and sulfite may modulate vital functions of activated leukocytes in vivo.

Air Pollutants↗
PubMed1989

Diesel soot particles catalyze the production of oxy-radicals.

The formation of a strong oxidant similar to the OH. radical is catalyzed by diesel soot particles in the presence of cysteine and hydrogen peroxide or in the presence of light. The oxidant(s) formed causes fragmentation of methylthioketobutyric acid measurable as ethylene release. Furthermore, the model carotenoid crocin is bleached and thiobarbituric-acid-reactive material (malondialdehyde) is produced from linolenic acid. All reactions are inhibited by scavengers (propyl gallate, alpha-tocopherol, diazobicyclooctane) and by catalase. The reactions observed suggest that the toxicity and mutagenicity of diesel soot particles is at least in part due to the formation of reactive oxygen species.

Air Pollutants↗
PubMed1989

Cysteine and crocin oxidation catalyzed by horseradish peroxidase.

The amino acid cysteine is oxidized by horseradish peroxidase, and the water-soluble carotenoid crocin is bleached by cooxidation. The monophenol p-hydroxyacetophenone stimulates oxygen uptake, cysteine oxidation and crocin bleaching, whereas its concentration does not change. Superoxide dismutase significantly enhances all these oxidative reactions. Addition of H2O2 is not required for these peroxidase-catalyzed oxidations.

Carotenoids↗
PubMed1989

[New biochemical models for cataract research].

In recent years, it has been suggested that reactive oxygen species are involved in the genesis of cataracts. To elucidate the basic reaction mechanisms underlying these processes and the influence of drugs, we developed simple biochemical model reactions. The purpose was to simulate cataractogenic processes and to document the effects of potential "anticataractous" drugs in vitro. Application tests allowed us to quantify the penetration rates and the enrichment processes of iodidecontaining drugs. Our results document the ability of KI to inhibit photodynamic reactions and related cataractogenic processes, such as lipid and sulfhydryl oxidation, as well as the structural changes of the lens proteins.

Adenosine Triphosphatases↗
PubMed1988

Cooperative stimulation by sulfite and crocidolite asbestos fibres of enzyme catalyzed production of reactive oxygen species.

Methylthioketobutyric acid has been used as an indicator for the production of reactive oxygen species during incubation with xanthine oxidase or NADH diaphorase in the presence of an autooxidizable quinone. The production of OH-radical-type oxidants is enhanced in the presence of crocidolite but not by the asbestos types chrysotile or amosite. This activity of crocidolite in the diaphorase system is further stimulated by bisulfite. Crocidolite-dependent ethylene formation from methylthioketo-butyric acid is inhibited by both superoxide dismutase and catalase. In the presence of both crocidolite and bisulfite, however, the inhibition by superoxide dismutase is preserved, but the inhibition by catalase is lost. Since in some respect the NADH-diaphorase quinone system may reflect the situation in the activated macrophage, crocidolite activation may represent a biochemical model system describing potential asbestos toxicity.

Asbestos↗
PubMed1988

Indole-3-acetic Acid oxidation and crocin bleaching by horseradish peroxidase.

During indoleacetic acid (IAA) oxidation by horseradish peroxidase the water soluble model polyene, crocin, is bleached. IAA-oxidation and crocin bleaching are stimulated at acidic pH as well as by the monophenol p-hydroxyacetophenone. IAA oxidation and crocin bleaching are neither influenced by catalase or superoxide dismutase nor by different OH-radical scavengers, whereas both ascorbate and propylgallate are inhibitory.

Journal Article↗
PubMed1987

Investigations on spruce decline in the Bavarian forest.

The primary damaging reactions in spruce needles may operate as follows: 1) Trees under "stress" produce the plant hormone ethylene. 2) Ethylene and ozone react extremely fast forming hydrogen peroxide and formaldehyde, compounds which may damage the wax layer. 3) Ozone as a very aggressive oxidant will inactivate membrane bound enzymes through oxidation of their thiol groups. Thus the translocation of sugars from the chloroplast into the phloem may be inhibited or blocked. The result will be an "over-reduction" of the electron transport chain resulting in the formation of reactive oxygen species in the light. These reactive oxygen species will induce lipid peroxidation and pigment co-oxidation. 4) The visible effects are bleached needles and an impairment of structural resistance against fungal infections. 5) In addition ozone will directly reduce the content of antifungal compounds such as p-HAP. 6) Furthermore p-HAP may be involved in the bleaching reaction after its release from picein. 7) Finally, fungi may penetrate the needles and eventually grow faster in bleached needles. Infected needles will become necrotic and abscise.

Acetophenones↗
PubMed1986

[Investigations of drug-related sulfhydryl oxidation in isolated rabbit lenses].

The appearance of cataract in human lenses mainly consists in the formation of a protein network initiated by oxidative processes. Two types of covalent bondings are produced in the cristallins during cataractogenesis: The formation of C-N bonds produced from amino groups of the cristallin proteins and aldehyd or keto groups derived from the oxidation of sugars or unsaturated fatty acids. The formation of S-S bonds from SH groups specially in the gamma-cristallins. These disulfid bonds are scarcely reducible by reductants such as ascorbic acid or glutathione. Experimentally these SS bonds can be produced in rabbit lenses by incubation with riboflavin in the light. The presence of Pherajod during the incubation period prevents the oxidation of SH groups.

Aged↗
PubMed1986

Time kinetics of hemoglobin and myoglobin activation by tetrachlorodecaoxide (TCDO).

In the presence of peroxidase, myoglobin or hemoglobin, Tetrachlorodecaoxide (TCDO) forms an active oxygen species which is similar to the product of the polymorphonuclear leucocyte (PMNL) myeloperoxidase reaction and the 'Klebanoff Model' of phagocytosis, but it is also produced under anaerobic conditions. Randomly destructive species such as the free OH radical or singlet oxygen are not formed. The kinetics of the heme-dependent activation vary according to the heme type present. In comparison to myoglobin, blood shows a 2 h delay in the appearance of maximal activity. On the basis of known biochemical and clinical-physiological data, a hypothesis can be proposed to explain the reoxygenation observed in hypoxic tissue, induced by TCDO via this activated heme species. Under normal physiological conditions, vasodilation occurs via catalysis by xanthine oxidase or PMNL-dependent activation of fatty acids.

Anti-Bacterial Agents↗