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Biomedical subjects

A Levy

Publications and source records attributed to A Levy.

At least 379 records · Page 21Linked to original sources
PubMed1986

Pneumonectomy in pulmonary mucormycosis complicating Behçet's disease.

A 37 year old man with Behçet's disease who was maintained on prolonged corticosteroid therapy, developed diabetic ketoacidosis and pneumonia. Secondary infection with mucor intervened with abscess formation cured by pneumonectomy. The association of Behçet's disease and mucormycosis has not been previously reported, although diabetes mellitus was almost certainly the predisposing cause. Surgical treatment offers the best chance of survival in similar cases.

Adult↗
PubMed1986

Pityriasis rotunda in a white patient. Report of the second case and review of the literature.

A 19-year-old white woman with pityriasis rotunda in whom no diagnosable disorder could be demonstrated is reported on herein. Pityriasis rotunda has been described in Oriental and black patients, usually in association with certain serious systemic diseases. Our patient appeared to have the second reported case of pityriasis rotunda in white persons. In both cases the dermatosis occurred in an otherwise healthy individual. Physicians should be alert to the possible occurrence of pityriasis rotunda in white patients. The literature on pityriasis rotunda is reviewed.

Adult↗
PubMed1986

Prayer nodules in Moslem men.

Seven cases of Israeli Moslem men with hyperkeratotic nodular callosities of the legs and forehead are reported. These patients were randomly encountered over a two-year period in our dermatology clinic. The nodules were attributed to repeated trauma to the legs and forehead sustained during Moslem prayer. This article familiarizes the clinician with the morphologic characteristics of these lesions, which may occur in some Moslem men.

Adult↗
PubMed1985

Low-temperature formation of a distal histidine complex in hemoglobin: a probe for heme pocket flexibility.

Pocket dynamics of horse deoxyhemoglobin and methemoglobin in the temperature range from 80 to 260 K is investigated. In both hemoglobins reversible conversion to a low-spin iron complex is observed at temperatures as low as 210 K. Electron spin resonance (ESR) and Mössbauer data assigned this low-spin iron complex to the coordination of N tau-His-E7 as a sixth nitrogenous ligand. The bonding of this ligand located 4 A from the iron indicates the presence of a thermally available conformation that exhibits a high degree of flexibility in the heme pocket. In deoxyhemoglobin, the formation of the bis(histidine) complex was accompanied by excitations of conformational fluctuations manifested through the temperature dependence of the Mössbauer-Lamb factor. The rate for the formation of this complex, with an associated energy barrier (greater than 60 KJ mol-1), is shown to serve as an index of heme pocket flexibility. Measurements performed on partially liganded (carbonmonoxy) hemoglobin indicate that partial ligation enhances conversion of the unliganded subunits to the bis(histidine) complex, suggesting that pocket dynamics is affected by subunit interactions.

Animals↗
PubMed1985

Characterization of the cycle of iron-mediated electron transfer from Adriamycin to molecular oxygen.

The anticancer drug adriamycin binds iron and these complexes cycle to reduce molecular oxygen (Zweier, J. L. (1984) J. Biol. Chem. 259, 6056-6058). Optical absorption, EPR, and Mössbauer spectroscopic data are correlated with polarographic O2 consumption and chemical Fe2+ extraction measurements in order to characterize each step in this cycle. Fe3+ binds to adriamycin at physiologic pH forming a complex with an optical absorbance maximum at 600 nm. EPR signals at g = 4.2 and g = 2.01, and a doublet Mössbauer spectrum with isomer shift delta = 0.57 mm/s and quadrupole splitting delta EQ = 0.74 mm/s are observed indicating that the Fe3+ bound to adriamycin is high spin S = 5/2. Under anaerobic conditions the absorbance maximum at 600 nm decreases with an exponential decay constant = 0.77 h-1, and the EPR and Mössbauer spectra of Fe3+-adriamycin similarly decrease as the Fe3+ is reduced to EPR silent Fe2+. The Fe2+-adriamycin complex which is formed exhibits a Mössbauer spectrum with delta = 1.18 mm/s and delta EQ = 1.82 mm/s indicative of high spin Fe2+. As the EPR spectra of Fe3+-adriamycin decrease on reduction of the Fe3+ to Fe2+ a signal of the oxidized adriamycin free radical appears at g = 2.004 with line width of 8 G. On exposure to O2 the absorption maximum at 600 nm, the Fe3+ EPR, and the Fe3+ Mössbauer spectra all return. Polarographic measurements demonstrate that O2 is consumed and that H2O2 is formed. Addition of high affinity Fe2+ chelators block O2 consumption indicating that Fe2+ formation is essential for O2 reduction. This cycle of iron-mediated O2 reduction can explain the formation of the reactive reduced oxygen and adriamycin radicals which are thought to mediate the biological activity of adriamycin.

Catalase↗