The use of germicidal ultraviolet light, vaporized hydrogen peroxide and dry heat to decontaminate face masks and filtering respirators contaminated with a SARS-CoV-2 surrogate virus.

BACKGROUND: In the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the supply of personal protective equipment remains under severe strain. To address this issue, re-use of surgical face masks and filtering facepiece respirators has been recommended; prior decontamination is paramount to their re-use. AIM: We aim to provide information on the effects of three decontamination procedures on porcine respiratory coronavirus (PRCV)-contaminated masks and respirators, presenting a stable model for infectious coronavirus decontamination of these typically single-use-only products. METHODS: Surgical masks and filtering facepiece respirator coupons and straps were inoculated with infectious PRCV and submitted to three decontamination treatments, ultraviolet (UV) irradiation, vaporized H2O2, and dry heat treatment. Viruses were recovered from sample materials and viral titres were measured in swine testicle cells. FINDINGS: UV irradiation, vaporized H2O2 and dry heat reduced infectious PRCV by more than three orders of magnitude on mask and respirator coupons and rendered it undetectable in all decontamination assays. CONCLUSION: This is the first description of stable disinfection of face masks and filtering facepiece respirators contaminated with an infectious SARS-CoV-2 surrogate using UV irradiation, vaporized H2O2 and dry heat treatment. The three methods permit demonstration of a loss of infectivity by more than three orders of magnitude of an infectious coronavirus in line with the United States Food and Drug Administration policy regarding face masks and respirators. It presents advantages of uncomplicated manipulation and utilization in a BSL2 facility, therefore being easily adaptable to other respirator and mask types.

Avaliação da microdureza e rugosidade superficial de uma resina composta submetida ao clareamento com peróxido de hidrogênio a 35% / Evaluation of microhardness and surface roughness of a composite resin under 35% hydrogen peroxide bleaching

Objetivo - Avaliar a microdureza e rugosidade superficial de uma resina composta microhíbrida à base de silorano, submetida ao clareamento imediato com peróxido de hidrogênio a 35%, autocatalisado, contendo cálcio. Métodos - Foram confeccionados 30 corpos de prova, divididos em 3 grupos experimentais: Grupo 1 (n=10): resina composta sem tratamento clareador; Grupo 2 (n=10): resina composta submetida a duas sessões de clareamento imediato com peróxido de hidrogênio a 35%; Grupo 3 (n=10): resina composta submetida a duas sessões de clareamento imediato com peróxido de hidrogênio a 35% com cálcio e armazenadas por 7 dias em saliva artificial a 37ºC. Foram realizados testes de rugosidade e microdureza para todos os grupos. Resultados - Os dados foram avaliados por análises de variância ao nível de significância de 5%, complementadas pelo teste de Tukey. Não houve diferença significativa entre os grupos quanto à rugosidade (p=0,481), ainda que a média do controle tenha sido maior do que dos outros grupos. Por outro lado, houve diferença significativa entre grupos quanto à microdureza (p=0,007). Os grupos G1 e G2 apresentaram médias de microdureza equivalentes e significativamente maiores do que a média do grupo G3. Conclusão - Pode-se concluir que, após o clareamento com peróxido de hidrogênio a 35% contendo cálcio, a rugosidade superficial da resina não se alterou e a microdureza diminuiu após uma semana de armazenamento em saliva artificial.

Objective - To evaluate the microhardness and surface roughness of a resin-based microhybrid silorano, subjected to bleaching with hydrogen peroxide 35%, self-catalyzed, containing calcium. Methods - There was prepared 30 specimens, divided into three groups: Group 1 (n = 10): composite without bleaching treatment, Group 2 (n = 10): composite subjected to two sessions immediately bleaching with hydrogen peroxide 35%, Group 3 (n = 10): composite subjected to two sessions immediately bleaching with hydrogen peroxide to 35% with calcium and stored for 7 days at 37°C in artificial saliva. Tests of roughness and hardness were performed for all groups. Results - Data were evaluated by analysis of variance at a significance level of 5%, complemented by the Tukey test. There was no significant difference between groups in terms of roughness (p = 0.481), although the average of the control was higher than the other groups. On the other hand, significant differences between groups in terms of microhardness (p = 0.007) were observed. The groups G1 and G2 showed average microhardness equivalent and significantly higher than the average of the group G3. Conclusion - It can be concluded that, after bleaching with hydrogen peroxide containing 35% calcium, the surface roughness of the resin did not change and microhardness decreased after one week storage in artificial saliva.

Chemical degradation of wastes of antineoplastic agents. 2: Six anthracyclines: idarubicin, doxorubicin, epirubicin, pirarubicin, aclarubicin, and daunorubicin.

OBJECT: Handling of genotoxic compounds commonly used in cancer chemotherapy generates contaminated wastes that require decontamination before disposal. Chemical methods are an alternative and/or a complement to incineration for the treatment of wastes and spills. METHODS: As part of a program initiated by the International Agency for Research on Cancer (IARC), 3 chemical methods readily available in the hospital environment--sodium hypochlorite (NaOCl, 5.25%), hydrogen peroxide (H2O2, < or = 30%) and Fenton reagent (FeCl2, 2H2O; 0.3 g in 10 ml H2O2, 30%)--are being tested for the degradation of a total of 32 antineoplastic agents. The efficiency of degradation was monitored by high-pressure liquid chromatography. The mutagenicity of the degradation residues were tested by the Ames test using tester strains Salmonella typhimurium TA 97a, TA 98, TA 100, and TA 102 with and without an exogenous metabolic activation system. RESULTS: The first results obtained for the degradation of cyclophosphamide, ifosfamide, and melphalan have been published in this journal. The present manuscript reports the results of the investigation of a series of six anthracyclines (aclarubicin, daunorubicin, doxorubicin, epirubicin, idarubicin, and pirarubicin) commonly used in chemotherapy treatment. Pharmaceutical preparations corresponding to the most concentrated administration solutions in either NaCl (0.9%) or dextrose (5%) were inactivated by oxidation volume/volume with each of the methods for at least 1 h. Complete degradation into nonmutagenic residues of all the tested compounds was observed after 1 h for the NaOCl (5.25%) treatment as previously reported for the first study. CONCLUSION: Sodium hypochlorite (5.25%) is an efficient reagent for the chemical degradation of the nine drugs tested thus far.