Sequential battery of COVID-19 testing to maximize negative predictive value before surgeries / Bateria sequencial de testes para COVID-19 para maximizar o valor preditivo negativo antes de operações

ABSTRACT SARS-CoV-2 is a novel virus which has proven to be highly contagious. Specific viral dynamics and immune response to the virus are yet to be fully defined and determining the sensitivity and specificity of the available testing methods is still a work in progress. This study examines the published information on the testing methods, and finds that yield of COVID-19 tests changes with specimen types and with time through course of illness. We propose a sequential battery of testing consisting of an epidemiologic survey, RT-PCR tests, serologic tests and chest CT on surgical candidates which may increase the negative predictive value, and facilitate surgical procedures.

RESUMO O SARS-CoV-2 é um novo vírus que provou ser altamente contagioso. A dinâmica viral específica e a resposta imunológica ao vírus ainda não foram totalmente definidas e a determinação da sensibilidade e especificidade dos métodos de teste disponíveis ainda está em andamento. Este estudo examina as informações publicadas sobre os métodos de testagem e conclui que o rendimento dos testes COVID-19 muda de acordo com o tipo de amostra e com o tempo de progressão da doença. Propomos uma bateria sequencial de testes, que consiste em um levantamento epidemiológico, testes de RT-PCR, testes sorológicos e tomografia computadorizada de tórax em candidatos a cirurgia, que podem aumentar o valor preditivo negativo e facilitar procedimentos cirúrgicos.

Abnormal lipid metabolism in collagen-induced arthritis rat model: In vitro, high resolution NMR spectroscopy based analysis.

Collagen-induced arthritis (CIA) was induced in female Wistar rats by intradermal injection of porcine immunization grade native collagen type II (Chondrex). Development and progression of CIA was monitored by studying histopathological, radiographical and biochemical features of arthritic manifestations in the knee joints, hind limb and blood plasma. In addition, oxidative stress status of arthritic animals was determined by measuring lipid peroxidation and the antioxidant enzymes: catalase, superoxide dismutase and glutathione peroxidase. High resolution proton NMR spectroscopy was employed for the analysis of lipid components in the lipid extracts of the joint tissue and plasma of collagen-induced arthritic and control rats. Triglyceride levels showed significant decreases in plasma (1.7 times) but were unchanged in the joint tissue of CIA rats as compared to control. One-dimensional proton NMR spectra showed a 6.2 times reduction in the quantity of choline-containing phospholipids in the plasma of CIA as compared to control rats. There was a 1.6 times elevation of choline-containing phospholipids in the joint tissue of CIA rats as compared to controls. Induction of arthritis showed a 4.0 times reduction in the level of total cholesterol in the plasma and 1.6 times elevation in the joint tissue of CIA rats as compared to controls. The ratio of saturated fatty acids to unsaturated fatty acids was 1.5 times significantly higher in joint tissue and 2.1 times significantly higher in plasma of CIA rats as compared to controls. The results demonstrated significantly altered lipid patterns in the joint tissue and plasma of collagen-induced arthritic rats as detected by one- and two-dimensional NMR spectroscopy compared with controls.