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Biomedical subjects

A J Carmichael

Publications and source records attributed to A J Carmichael.

At least 91 records · Page 5Linked to original sources
PubMed1990

Speckled compound naevus.

We report a case of a localized speckled compound naevus arising within normally pigmented skin. Speckled melanocytic naevi are reviewed and the distinctive features of the case enumerated.

Adolescent↗
PubMed1990

Endothelial cells as a source of oxygen-free radicals. An ESR study.

Endothelial cells were subjected to anoxia/reoxygenation in order to simulate some of the free radical mechanisms occurring in ischaemia/reperfusion. With ESR and spin trapping using the spin traps 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) and 3,3,5,5-dimethyl-1-pyrroline-1-oxide (M4PO), the results show that upon reoxygenation of endothelial cells, following a period of anoxia, these cells generate superoxide (O2-.). Cytotoxicity of the spin traps was measured by standard trypan blue exclusion methods. Cell injury or death was measured at various times during reoxygenation by lactate dehydrogenase (LDH) release. Experiments using oxyupurinol, SOD, CAT and a combination of SOD and CAT show that while oxypurinol partially prevents spin adduct formation, the combination of SOD and CAT is more effective in doing so. These results suggest that the majority of the oxygen radicals produced by endothelial cells are done so exogenously. The results also suggest that endothelial cells are not only a source of oxygen radicals but also a target.

Animals↗
PubMed1990

Reaction of vanadyl with hydrogen peroxide. An ESR and spin trapping study.

Vanadyl reacts with hydrogen peroxide forming hydroxyl radicals in a Fenton-like reaction. The hydroxyl radicals were spin trapped and identified using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The quantity of hydroxyl radicals spin trapped during the reaction between vanadyl and hydrogen peroxide are equal to half of the hydroxyl radicals spin trapped during the reaction between ferrous ions and hydrogen peroxide. Experiments in the presence of formate show that this hydroxyl radical scavenger effectively competes with DMPO preventing the formation of the DMPO-OH adduct. However, in experiments using ethanol as the hydroxyl radical scavenger it was not possible to completely prevent the formation of DMPO-OH. The formation of this additional DMPO-OH in the presence of ethanol does not depend on the concentration of dissolved oxygen, but does depend on the concentration of hydrogen peroxide added to the vanadyl solution. The results suggest that the additional DMPO-OH formed in the presence of ethanol originates from a vanadium (V) intermediate. This intermediate may oxidize DMPO leading to the formation of DMPO-O2- which rapidly decomposes forming DMPO-OH.

Cyclic N-Oxides↗
PubMed1989

Familial sarcoidosis: high ethnic prevalence.

We report three sisters of Irish extraction who all developed sarcoidosis. The cases emphasize both the familial and ethnic preponderance of sarcoidosis which has not been adequately emphasized in the dermatology literature.

Family↗