Biomedical subjects

A Assmann

Publications and source records attributed to A Assmann.

21 records · Page 2Linked to original sources

PubMed1981

[Changes in the pharyngeal bacterial flora during hyperbaric oxygenation].

Qualitative and quantitative bacteriological tests of throat smears were carried out on the following three groups of patients: 1) Patients exposed to several 90-minute sequences of oxygen hyperbaria, at a height of 2.2 ata O2, at intervals of 2 to 3 days. 2) Patients exposed to a single 30-minute dose of oxygen hyperbaria at a height of 2.5 ata O2/the oxygen test. 3) Patients who had never been exposed to oxygen hyperbaria. Several hundred bacterials strains of the Streptococcus, Staphylococcus, Klebsiella and Nocardia genus were isolated from the material collected from the tested patients over intervals of a few days. The collected samples were when subjected to a detailed bacteriological analysis. At the same time bacteriological tests were performed at intervals on the hyperbaric atmosphere of the therapeutic pressure chamber, the walls of the chamber, and the masks used by the patients during the administration of hyperbaric oxygen. A certain degree of qualitative and quantitative changes (number reduction of bacterial strains) was observed. The authors attribute these results to the influence of hyperbaric oxygenation both on the microorganisms, as well as on a given patient's reactivity.

Bacteriological Techniques↗

PubMedDate not supplied

Protection against peroxynitrite by selenoproteins.

Cellular defense against excessive peroxynitrite generation is required to protect against DNA strand-breaks and mutations and against interference with protein tyrosine-based signaling and other protein functions due to formation of 3-nitrotyrosine. We recently demonstrated a role of selenium-containing enzymes catalyzing peroxynitrite reduction. Glutathione peroxidase (GPx) protected against the oxidation of dihydrorhodamine 123 (DHR) by peroxynitrite more effectively than ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one), a selenoorganic compound exhibiting a high second-order rate constant for the reaction with peroxynitrite, 2 x 10(6) M-1s-1. The maintenance of protection by GPx against peroxynitrite requires GSH as reductant. Similarly, selenomethionine but not selenomethionine oxide exhibited inhibition of rhodamine 123 formation from DHR caused by peroxynitrite. In steady-state experiments, in which peroxynitrite was infused to maintain a 0.2 microM concentration, GPx in the presence of GSH, but neither GPx nor GSH alone, effectively inhibited the hydroxylation of benzoate by peroxynitrite. Under these steady-state conditions peroxynitrite did not cause loss of 'classical' GPx activity. GPx, like selenomethionine, protected against protein 3-nitrotyrosine formation in human fibroblast lysates, shown in Western blots. The formation of nitrite rather than nitrate from peroxynitrite was enhanced by GPx, ebselen or selenomethionine. The selenoxides can be effectively reduced by glutathione, establishing a biological line of defense against peroxynitrite. The novel function of GPx as a peroxynitrite reductase may extend to other selenoproteins containing selenocysteine or selenomethionine. Recent work on organotellurium compounds revealed peroxynitrite reductase activity as well. Inhibition of dihydrorhodamine 123 oxidation correlated well with the GPx-like activity of a variety of diaryl tellurides.

Animals↗

PubMedDate not supplied

Buschke-Ollendorff syndrome--differential diagnosis of disseminated connective tissue lesions.

We report a 5-year-old boy presenting with multiple elastic type nevi and osteopoikilosis who was diagnosed as having Buschke-Ollendorff syndrome at an early age. Connective tissue lesions may present as the main symptom of varying clinical entities with different outcomes. Differential diagnosis includes papular elastorrhexis, fibroelastolytic papules of the neck, papular acne scars, and late onset focal dermal elastosis. Rare genodermatoses, i.e. Buschke-Ollendorff syndrome, pseudoxanthoma elasticum, juvenile hyaline fibromatosis and familiar cutaneous collagenoma should be carefully evaluated to provide appropriate genetic counseling and to avoid unnecessary treatment procedures.

Child, Preschool↗