Evaluation of emerging inflammatory markers for predicting oxygen support requirement in COVID-19 patients.

Coronavirus disease 2019 (COVID-19), a highly contagious pathogenic viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly and remains a challenge to global public health. COVID-19 patients manifest various symptoms from mild to severe cases with poor clinical outcomes. Prognostic values of novel markers, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and C-reactive protein to lymphocyte ratio (CLR) calculated from routine laboratory parameters have recently been reported to predict severe cases; however, whether this investigation can guide oxygen therapy in COVID-19 patients remains unclear. In this study, we assessed the ability of these markers in screening and predicting types of oxygen therapy in COVID-19 patients. The retrospective data of 474 COVID-19 patients were categorized into mild and severe cases and grouped according to the types of oxygen therapy requirement, including noninvasive oxygen support, high-flow nasal cannula and invasive mechanical ventilator. Among the novel markers, the ROC curve analysis indicated a screening cutoff of CRP ≥ 30.0 mg/L, NLR ≥ 3.0 and CLR ≥ 25 in predicting the requirement of any type of oxygen support. The NLR and CLR with increasing cut-off values have discriminative power with high accuracy and specificity for more effective oxygen therapy with a high-flow nasal cannula (NLR ≥ 6.0 and CLR ≥ 60) and mechanical ventilator (NLR ≥ 8.0 and CLR ≥ 80). Our study thus identifies potential markers to differentiate the suitable management of oxygen therapy in COVID-19 patients at an earlier time for improving disease outcomes with limited respiratory support resources.

Induction of genotoxicity and mutagenic potential of heavy metals in Thai occupational workers.

Heavy metals are widely used in many industries in Thailand and found in the environment. Occupational exposure to heavy metals is often chronic and caused by environmental contaminations, potentially leading to mutations and cancer. Although the genotoxic effects of occupational exposure to multiple heavy metals have been extensively studied, the findings regarding their genotoxicity are conflicting. In this study, we focused on investigating the genotoxic effects of certain heavy metals mixtures, including lead (Pb), copper (Cu), zinc (Zn), and tin (Sn), to which workers are exposed in the manufacturing industry. The cytokinesis-blocked micronucleus (CBMN) assay in peripheral blood lymphocytes was performed, and DNA damage was assessed by measuring tumour-associated protein levels and 8-hydroxy-2'-deoxyguanosine (8-OHdG) generated by oxidative stress that causes cytotoxicity. The occupational exposure group included 110 workers exposed to heavy metal mixtures and 105 matched control subjects. We found statistically significant differences in the blood Pb, Sn, and Cu levels between the exposed workers and the control subjects (p < 0.001). Analysis of micronuclei (MN) in peripheral blood lymphocytes revealed a significantly increased frequency of MN in exposed workers compared with that in control subjects (p<0.05). Non-smoking exposed workers were selected for 8-OHdG formation and mutant p53 tests, and significant differences in the mean plasma 8-OHdG concentration (p < 0.001) were found between the occupational exposure and the control group, but no differences were found in the levels of mutant p53. Thus, chronic exposure to different heavy metals causes genotoxic effects in humans. Furthermore, the CBMN assay and 8-OHdG formation can be used as surrogate biomarkers to identify and monitor groups with higher carcinogenic risk in the early stages of toxicity. In summary, our results indicate that mixtures of heavy metals (Pb, Sn, and Cu) in manufacturing industries pose an elevated health risk due to DNA damage.