Chemical burn induced by cutaneous exposure to a concentrated sodium hypochlorite and alkyl sulfate solution.

BACKGROUND: Acute irritant contact dermatitis induced by cutaneous exposure to chemicals is a common dermatologic problem in the workplace. In severe cases, irritant contact responses can result in a caustic burn. Chemical burn induced by concentrated sodium hypochlorite (the active ingredient in bleach) has been reported infrequently in the literature, with no previously reported cases of chemical burn due to an alkyl sulfate (a common surfactant in cleaning fluids). Here we describe a chemical burn in a 16-year-old girl resulting from exposure to a solution of concentrated sodium hypochlorite and alkyl sulfate applied as a sanitizer to the interior of roller skates worn at work. OBSERVATIONS: The diagnosis was made on the basis of the patient's exposure history, clinical appearance, and laboratory results. On physical examination, the erythematous plaque, located at the site of chemical exposure, had intact skin lines, surrounding edema, and decreased sensitivity to touch. The peripheral white blood cell count was within normal limits and bacterial and fungal cultures from the lesion were negative. CONCLUSIONS: The irritant effect of exposure to chemicals, including those that usually are not major irritants, and the possible additive effect of simultaneous exposure to different chemicals, should be considered in the differential diagnosis of acute dermatitis of unknown etiology. Moreover, increased reporting of cases of chemical-induced acute irritant contact dermatitis will help lead to crucial early and appropriate treatment.

Increased ubiquitination and other covariant phenotypes attributed to a strain- and temperature-dependent defect of reovirus core protein mu2.

Reovirus replication and assembly are thought to occur within cytoplasmic inclusion bodies, which we call viral factories. A strain-dependent difference in the morphology of these structures reflects more effective microtubule association by the mu2 core proteins of some viral strains, which form filamentous factories, than by those of others, which form globular factories. For this report, we identified and characterized another strain-dependent attribute of the factories, namely, the extent to which they colocalized with conjugated ubiquitin (cUb). Among 16 laboratory strains and field isolates, the extent of factory costaining for cUb paralleled factory morphology, with globular strains exhibiting higher levels by far. In reassortant viruses, factory costaining for cUb mapped primarily to the mu2-encoding M1 genome segment, although contributions by the lambda3- and lambda2-encoding L1 and L2 genome segments were also evident. Immunoprecipitations revealed that cells infected with globular strains contained higher levels of ubiquitinated mu2 (Ub-mu2). In M1-transfected cells, cUb commonly colocalized with aggregates formed by mu2 from globular strains but not with microtubules coated by mu2 from filamentous strains, and immunoprecipitations revealed that mu2 from globular strains displayed higher levels of Ub-mu2. Allelic changes at mu2 residue 208 determined these differences. Nocodazole treatment of cells infected with filamentous strains resulted in globular factories that still showed low levels of costaining for cUb, indicating that higher levels of costaining were not a direct result of decreased microtubule association. The factories of globular strains, or their mu2 proteins expressed in transfected cells, were furthermore shown to gain microtubule association and to lose colocalization with cUb when cells were grown at reduced temperature. From the sum of these findings, we propose that mu2 from globular strains is more prone to temperature-dependent misfolding and as a result displays increased aggregation, increased levels of Ub-mu2, and decreased association with microtubules. Because so few of the viral strains formed factories that were regularly associated with ubiquitinated proteins, we conclude that reovirus factories are generally distinct from cellular aggresomes.

Reovirus nonstructural protein mu NS recruits viral core surface proteins and entering core particles to factory-like inclusions.

Mammalian reoviruses are thought to assemble and replicate within cytoplasmic, nonmembranous structures called viral factories. The viral nonstructural protein mu NS forms factory-like globular inclusions when expressed in the absence of other viral proteins and binds to the surfaces of the viral core particles in vitro. Given these previous observations, we hypothesized that one or more of the core surface proteins may be recruited to viral factories through specific associations with mu NS. We found that all three of these proteins--lambda 1, lambda 2, and sigma 2--localized to factories in infected cells but were diffusely distributed through the cytoplasm and nucleus when each was separately expressed in the absence of other viral proteins. When separately coexpressed with mu NS, on the other hand, each core surface protein colocalized with mu NS in globular inclusions, supporting the initial hypothesis. We also found that lambda 1, lambda 2, and sigma 2 each localized to filamentous inclusions formed upon the coexpression of mu NS and mu 2, a structurally minor core protein that associates with microtubules. The first 40 residues of mu NS, which are required for association with mu 2 and the RNA-binding nonstructural protein sigma NS, were not required for association with any of the three core surface proteins. When coexpressed with mu 2 in the absence of mu NS, each of the core surface proteins was diffusely distributed and displayed only sporadic, weak associations with mu 2 on filaments. Many of the core particles that entered the cytoplasm of cycloheximide-treated cells following entry and partial uncoating were recruited to inclusions of mu NS that had been preformed in those cells, providing evidence that mu NS can bind to the surfaces of cores in vivo. These findings expand a model for how viral and cellular components are recruited to the viral factories in infected cells and provide further evidence for the central but distinct roles of viral proteins mu NS and mu 2 in this process.