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Biomedical subjects

R S Levy

Publications and source records attributed to R S Levy.

At least 37 records · Page 2Linked to original sources
PubMed1983

Penicillamine: review and cutaneous manifestations.

D-Penicillamine, a heavy metal chelator used in the treatment of Wilson's disease and other conditions, may be associated with both noncutaneous and cutaneous side effects. Some of the cutaneous lesions are due to a toxic-metabolic effect on connective tissue; some may be explained on the basis of autoimmunity; some are acute sensitivity reactions, and some are secondary to unknown mechanisms. The types of cutaneous manifestations may, in some instances, be correlated with the disease being treated and the dosage and duration of penicillamine therapy.

Autoimmune Diseases↗
PubMed1983

Evoked potential correlates of left hemisphere dominance in covert articulation.

Evoked Potentials (EPs) to a click stimulus were recorded at the temporal areas of both hemispheres of dextral subjects engaged in covert rehearsal of a verbal passage or in covert rehearsal of musical passages. A pattern of left hemisphere attenuation of the click EPs was observed in all subjects during speech rehearsal but not during music rehearsal. The implications of these findings for the issue of electroencephalographic localization of speech production mechanisms in the left hemisphere are discussed.

Adult↗
PubMed1983

Clindamycin compared with penicillin for the treatment of anaerobic lung abscess.

The clinical efficacy of clindamycin was compared with that of penicillin in a randomized study of the treatment of community-acquired putrid lung abscess. After starting therapy, patients treated with clindamycin had a shorter febrile period and fewer days of fetid sputum than patients treated with penicillin (mean 4.4 versus 7.6 days and 4.2 versus 8.0 days, respectively, p less than 0.05). Four of 20 patients treated with penicillin had clinically significant pulmonary or pleural extension of their infection within 10 days after starting therapy; this was not found in any of 19 patients treated with clindamycin (p less than 0.05). Penicillin treatment failed in two additional patients after 20 days of therapy. Within 1 month after treatment, 1 of 4 patients given penicillin for 3 weeks had relapse, but none of the 13 patients given clindamycin for 3 or 6 weeks, and none of the 5 patients given penicillin for 6 weeks had relapse. Overall, only 8 of 15 patients treated with penicillin who could be followed to the end of the study were cured, whereas all 13 patients treated with clindamycin who could be followed were cured (p less than 0.01). These results suggest that penicillin may not be optimal therapy for anaerobic lung abscess.

Adult↗
PubMed1977

Structure-function relationships in TPN-dependent isocitrate dehydrogenase. I. Electron paramagnetic resonance studies of the interaction of enzyme-bound Mn(II) with substrates, cofactors, and substrate analogues.

Electron paramagnetic resonance (EPR) spectra were obtained for various isocitrate dehydrogenase-Mn(II) complexes. The qualitative effects of the binding of substrates, nucleotides, and substrate analogues on the isotropic character of the electronic environment of enzyme-bound Mn(II) were subsequently investigated. The addition of isocitrate produces a markedly anisotropic spectrum whereas alpha-ketoglutarate does not alter the spectrum of enzyme-Mn(II) substantially. This suggests direct coordination of isocitrate to the Mn(II) but perphaps a different mode of binding for alpha-ketoglutarate. Other studies demonstrated mutually exclusive binding relationships between TPN and TPNH, between Mn-isocitrate and TPNH, and between HCO3-(CO2) and formate or thiocyanate. Indirect evidence supporting CO2 rather than HCO3-as the actual reactive species which binds to the enzyme in the reductive carboxylation reaction is presented on the basis of the results of the formate and thiocyanate studies. From the EPR results recorded for ternary, quaternary, and quinary enzyme-substrate complexes, correlations between the appearance of fine structure signals and the binding of individual substrates and/or nucleotides are found, and tentative assignments of such signals are made on this basis. Additional studies were conducted to determine binding constants for Mg(II) Co(II), and Co-isocitrate, and a comparison was made with kinetically determined binding constants.

Animals↗
PubMed1969

Intracranial self-stimulation and the rapid decline of frustrative nonreward.

Animals deprived of reward for a task previously rewarded behave differently, depending on whether the reward is food or positive brain stimulation. Unlike the relatively stable frustration effects obtained with conventional reward, frustration produced by withholding brain stimulation dissipates rapidly with time.

Animals↗