SARS-CoV-2 and Other Respiratory Viruses: What Does Oxidative Stress Have to Do with It?

The phenomenon of oxidative stress, characterized as an imbalance in the production of reactive oxygen species and antioxidant responses, is a well-known inflammatory mechanism and constitutes an important cellular process. The relationship of viral infections, reactive species production, oxidative stress, and the antiviral response is relevant. Therefore, the aim of this review is to report studies showing how reactive oxygen species may positively or negatively affect the pathophysiology of viral infection. We focus on known respiratory viral infections, especially severe acute respiratory syndrome coronaviruses (SARS-CoVs), in an attempt to provide important information on the challenges posed by the current COVID-19 pandemic. Because antiviral therapies for severe acute respiratory syndrome coronaviruses (e.g., SARS-CoV-2) are rare, knowledge about relevant antioxidant compounds and oxidative pathways may be important for understanding viral pathogenesis and identifying possible therapeutic targets.

Proinflammatory and regulatory mechanisms in allergic contact dermatitis caused by methylchloroisothiazolinone and methylisothiazolinone.

BACKGROUND: Methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) are the cause of an increasing number of contact allergies. Understanding the mechanisms by which MCI/MI induces proinflammatory and regulatory factors production is necessary to understand the outcome of allergic contact dermatitis (ACD). OBJECTIVES: To evaluate the dysfunction of proinflammatory cytokines and regulatory factors in the positive MCI/MI patch test at the transcriptional and protein expression levels. Moreover, to analyse the cytokines production induced by MI in peripheral blood mononuclear cells (PBMCs). MATERIALS AND METHODS: The selected patients had positive MCI/MI patch test results. The expression of proinflammatory factors was evaluated by q-PCR and immunochemistry at 48 hours of positive MCI/MI patch test. The MCI/MI- or MI- induced secretion of IL-1ß, TNF and IL-6 by PBMC was analysed by flow cytometry. RESULTS: The results showed a decreased TLR4 expression with upregulated IL6, FOXP3, IL10 and TGFß mRNA expression as assessed by q-PCR at the site of the MCI/MI skin reaction. We detected increased protein levels of TLR4, FOXP3 and IL-10 in the dermis layer in the ACD reaction by immunocitochemistry. Moreover, MCI/MI induced proinflammatory cytokine production by PBMC through the NF-κB signalling pathway. CONCLUSION: Considering the altered innate immune response triggered by MCI/MI sensitization, these findings indicate that the regulatory process at the induction phase of ACD is a crucial mechanism. Given the increase in occupational and domestic exposure to MCI/MI, the underlying immunological mechanisms should be understood.

Dermatosis due to plants (phytodermatosis).

Dermatosis caused by plants is relatively common and may occur by various pathogenic mechanisms. Dermatitis due to physical trauma, pharmacological action, irritation, sensitization, mediated by IgE and induced by light are described. Pseudophytodermatosis caused by plant-delivered elements is also described in the introduction to this work.

The influence of the amount of sunscreen applied and its sun protection factor (SPF): evaluation of two sunscreens including the same ingredients at different concentrations.

BACKGROUND: To estimate labeled sun protection factor (SPF) for sunscreen, the amount of product applied on volunteers, according to food and drug administration (FDA) and International protocols, is 2 mg/cm(2). However, different studies have shown that consumers actually apply much less product when exposed to the sun. Previous studies have reported contradictory findings in an attempt to correlate the amount applied in relation to SPF. The objective of the present study was to estimate the influence of the quantity of sunscreen applied in the determination of SPF, according to the FDA methodology. SUBJECTS AND METHODS: Forty volunteers were included in two groups (SPF 15 and 30). The selected sunscreen was then applied in four different quantities (2, 1.5, 1.0 and 0.5 mg/cm(2)). All areas were irradiated with a solar simulator. After 24 h, the minimal erythemal dose (MED) and SPF were determined. RESULTS: In both groups, we observed that the SPF decreased when the amount of sunscreen applied was decreased. The differences between the 2 mg/cm(2) area and the others were significant in both groups (P<0.001). The correlation between specified SPF and applied amount grew exponentially. CONCLUSION: The protection provided by sunscreen is related to the amount of product applied. It is essential to educate consumers to apply larger amounts of sunscreen for adequate photoprotection.

Discoid lupus erythematosus in children--a retrospective study of 34 patients.

Discoid lupus erythematosus is much less frequent and studied in children. We undertook a retrospective study of 34 children less than 16 years of age with this disease, seen over a period of 9 years. A female predominance of 2:1 was found. An association between discoid lupus erythematosus and systemic lupus erythematosus was observed in 23.5% of patients, a higher proportion compared to adult discoid lupus erythematosus. Disseminated lesions were much more frequent in patients with criteria for systemic lupus erythematosus (87.5% vs 34%), suggesting that it could be associated with a worse prognosis. Histologic findings were similar to those observed in adult discoid lupus erythematosus.

Direct immunofluorescence on uninvolved, lesional and perilesional skin in patients with endemic pemphigus foliaceus (fogo selvagem).

BACKGROUND: Research on direct immunofluorescence in pemphigus foliaceus ("fogo selvagem") has been focused mainly on the study of perilesional and lesional skin, while little attention has been given to uninvolved skin. We analyzed the frequency of IgA, IgM, IgG and its subclasses (IgG1, IgG2, IgG3 and IgG4) and C3 complement fraction deposition in intercellular spaces (ICS) and basal membrane zone (BMZ) in uninvolved, lesional and perilesional skin from 47 fogo selvagem patients. MATERIAL/METHODS: For each patient biopsies were collected from lesional, perilesional and uninvolved skin, and then analyzed by direct immunofluorescence. The panel of antibodies consisted of IgA, IgM, IgG and its subclasses (IgG1, IgG2, IgG3 and IgG4) and C3 complement fraction. RESULTS: The results showed a predominance of IgG and IgG4 deposit in all skin samples, followed by C3 complement fraction and IgG1 deposits. The positive response for IgG on uninvolved (91.48%), lesional (93.61%) and perilesional (97.87%) skin was similar to that found for IgG4 in the same samples: 95.74%, 95.74% and 97.87%, respectively. Regarding IgG1, the uninvolved skin showed lower results (14.89%) than the lesional (29.78%) and perilesional skin (29.78%). Concerning C3 complement fraction, the perilesional skin showed higher results (40.42%) than the uninvolved and lesional skin (34.04% for both). CONCLUSIONS: The results suggest the importance of uninvolved skin for direct immunofluorescence in the diagnostics of pemphigus foliaceus. Our results suggest that any cutaneous region can demonstrate pemphigus antibodies by direct immunofluorescence.