Vasculitis attributed to the nicotine patch (Nicotinell).

Nicotine-containing patches are used to facilitate tobacco withdrawal by mitigating abstinence symptoms and diminishing craving. We describe two patients who developed vasculitis in association with the use of a nicotine patch. The first concerns a patient who developed fever, arthritis, a generalized erythema and purpuric lesions, after 3 days use of nicotine patches. Laboratory results and a skin biopsy confirmed the diagnosis of a leucocytoclastic vasculitis. After stopping use of the patch, the patient recovered. On challenge, the symptoms reappeared. The second patient developed purpuric lesions during the use of nicotine patches, and recovered fully after these were stopped. In these patients, nicotine patches seem to be causally related to the development of vasculitis.

Sensitization to povidone-iodine.

Eight patients are described with adverse skin reactions to povidone-iodine-containing preparations (Betadine). Patch test reactions were positive to povidone-iodine 5 or 10 per cent in petrolatum or to Betadine Solution, Ointment, or Scrub. In five of eight patients, also tested with potassium iodide in concentrations ranging from 5 to 20 per cent in petrolatum, the reactions were negative. Open tests with iodine tincture performed in three patients were completely negative. Allergy to povidone-iodine seems not to be based on sensitization to iodine.

The use of intravenous cannulae and the occurrence of thrombophlebitis.

The occurrence of thrombophlebitis in a coronary care unit was studied in relation to the use of short plastic intravenous cannulae. The incidence of thrombophlebitis was 51% in cases where cannulae were used for continuous infusion of glucose 5% and 13% for cannulae which were locked after the injection of heparin. Only one case of infectious thrombophlebitis was seen. The other cases of thrombophlebitis had a chemical or mechanical aetiology. Replacement of glucose 5% by a NaCl 0.9% solution for continuous infusion reduced the incidence of thrombophlebitis to 33%. Heparin-locked cannulae, to provide rapid access to the patient's circulation, proved to be a safe alternative to continuous infusion.

Discrete catalytic sites for quinone in the ubiquinol-cytochrome c2 oxidoreductase of Rhodopseudomonas capsulata. Evidence from a mutant defective in ubiquinol oxidation.

A non-photosynthetic mutant (Ps-) of Rhodopseudomonas capsulata, designated R126, was analyzed for a defect in the cyclic electron transfer system. Compared to a Ps+ strain MR126, the mutant was shown to have a full complement of electron transfer components (reaction centers, ubiquinone-10, cytochromes b, c1, and c2, the Rieske 2-iron, 2-sulfur (Rieske FeS) center, and the antimycin-sensitive semiquinone). Functionally, mutant R126 failed to catalyze complete cytochrome c1 + c2 re-reduction or cytochrome b reduction following a short (10 microseconds) flash of actinic light. Evidence (from flash-induced carotenoid band shift) was characteristic of inhibition of electron transfer proximal to cytochrome c1 of the ubiquinol-cytochrome c2 oxidoreductase. Three lines of evidence indicate that the lesion of R126 disrupts electron transfer from quinol to Rieske FeS: 1) the degree of cytochrome c1 + c2 re-reduction following a flash is indicative of electron transfer from Rieske FeS to cytochrome c1 + c2 without redox equilibration with an additional electron from a quinol; 2) inhibitors that act at the Qz site and raise the Rieske FeS midpoint redox potential (Em), namely 5-undecyl-6-hydroxy-4,7-dioxobenzothiazole or 3-alkyl-2-hydroxy-1,4-napthoquinone, have no effect on cytochrome c1 + c2 oxidation in R126; 3) the Rieske FeS center, although it exhibits normal redox behavior, is unable to report the redox state of the quinone pool, as metered by its EPR line shape properties. Flash-induced proton binding in R126 is indicative of normal functional primary (QA) and secondary (QB) electron acceptor activity of the photosynthetic reaction center. The Qc functional site of cytochrome bc1 is intact in R126 as measured by the existence of antimycin-sensitive, flash-induced cytochrome b reduction.

The problem of the sensitization to dithiocarbamates in thiuram-allergic patients.

Because of the occurrence of hand dermatitis in members of a surgical staff due to allergy to thiuram-containing rubber gloves, an investigation was performed about cross-sensitization between thiuram compounds and dithiocarbamates. Positive reactions to dithiocarbamates were compared with reactions to 8 brands of hypo-allergenic or dithiocarbamate-containing surgical gloves. There appeared to be a marked difference in reactions to the dithiocarbamate-containing gloves. Some brands gave negative or nearly always negative reactions, while other brands caused many positive reactions. Thiuram-allergic patients were advised to wear nonreacting rubber gloves or PVC gloves.

Redox potential dependence of photophosphorylation and electron transfer in continuous illumination of Rhodopseudomonas sphaeroides chromatophores.

The dependence on redox potential (Eh) of the steady-state photophosphorylation rate in chromatophores of Rhodopseudomonas sphaeroides Ga was measured using slowly equilibrating (and hence less interfering) redox mediators. The remaining interference of the mediators was taken into account by extrapolating to zero mediator concentration. The extents of cytochrome redox reactions (in the presence of antimycin) and of the carotenoid shift were similarly measured. The redox titration of cytochrome c oxidation is consistent with a requirement for prior cytochrome c2 reduction and prior Q1 (primary electron acceptor) oxidation, while the titration of cytochrome b reduction is consistent with a requirement for prior (BChl)2 reduction and prior cytochrome b560 oxidation. The steady-state carotenoid shift extent is a much more broadly peaked function of Eh than is the extent following a single-turnover flash, indicating that the transmembrane electrical potential difference can be built up to significant levels by minimal rates of electron flow. The photophosphorylation rate, in contrast, is much more strongly Eh dependent, supporting the concept of a threshold membrane energization below which phosphorylation cannot occur. Earlier work by others showing a requirement for equilibrium cytochrome c2 reduction and Q1 oxidation is clearly confirmed. A much greater enhancement in phosphorylation rate was found at low Eh than has heretofore been reported. This threefold enhancement is discussed in relation to the equilibrium redox states of the ubiquinone-10 complement of the chromatophore membrane.

Electron and proton transport in the ubiquinone cytochrome b-c2 oxidoreductase of Rhodopseudomonas sphaeroides. Patterns of binding and inhibition by antimycin.

The effect of antimycin on the ubiquinone cytochrome b-c2 (Q b-c2) oxidoreductase of the photosynthetic bacterium Rhodopseudomonas sphaeroides has been studied under controlled oxidation-reduction potential (Eh) conditions by equilibrium measurements and by rapid kinetic analysis of single turnover flash.induced electron and proton translocations. 1. Antimycin shifts the alpha-band of ferro b50 (lambda max 560 nm) by 1 to 2 nm toward the red but has no apparent effect on the equilibrium oxidation-reduction midpoint potential of the cytochrome. 2. This red shift is proportional to the antimycin added until a "titer" of 0.7 +/- 0.1 antimycin per reaction center (RC) is approached. With a similar titer antimycin essentially abolishes the following millisecond reactions activated by saturating single turnover flashes: reduction of ferri c2, oxidation of ferro b, Phase III of the membrane-potential-indicating band shift of endogenous carotenoid pigments, and the uptake of 1 of the 2 protons taken up per electron transferred. Such titrations indicate that the binding (KD approximately 10(-9) m) and mode of inhibition of antimycin are noncooperative and are independent of the membrane's coupling status and of the pH and Eb over the range in which electron transport is operative. 3. In the presence of excess antimycin a partial recovery of ferri c2 reduction is seen when the intensity of the flash is diminished, but only at Eh values such that Z (a special quinone serving as reductant for ferri c2) is reduced but b50 is oxidized before activation. These results are consistent with the following model. Each Q b-c2 oxidoreductase complex includes one antimycin binding site, one b50, and one Z. These complexes and the c2 . RC complexes, present in an 0.7:1 ratio, are to some degree mobile with respect to each other. Ferri b50 can be reduced either via the quinones of the RC or via Z in a reaction also involving c2. The former route is kinetically dominant in the presence of antimycin, but the latter route is the means for "oxidant-induced reduction" and depends on the collisional interaction of the oxidoreductase and c2 . RC complexes. Antimycin interferes with neither of these two routes but does inhibit the oxidation of ferro b50; all the other inhibitory effects are consequent on this.