COVID-19 is a global catastrophic event that causes severe acute respiratory syndrome. The mechanism of the disease remains unclear, and hypoxia is one of the main complications. There is no currently approved protocol for treatment. The microbial threat as induced by COVID-19 causes the activation of macrophages to produce a huge amount of inflammatory molecules and nitric oxide (NO). Activation of macrophages population into a pro-inflammatory phenotype induces a self-reinforcing cycle. Oxidative stress and NO contribute to this cycle, establishing a cascade inflammatory state that can kill the patient. Interrupting this vicious cycle by a simple remedy may save critical patients’ lives. Nitrite, nitrate (the metabolites of NO), methemoglobin, and prooxidant-antioxidant-balance levels were measured in 25 ICU COVID-19 patients and 25 healthy individuals. As the last therapeutic option, five patients were administered methylene blue-vitamin C–N-acetyl Cysteine (MCN). Nitrite, nitrate, methemoglobin, and oxidative stress were significantly increased in patients in comparison to healthy individuals. Four of the five patients responded well to treatment. In conclusion, NO, methemoglobin and oxidative stress may play a central role in the pathogenesis of critical COVID-19 disease. MCN treatment seems to increase the survival rate of these patients. Considering the vicious cycle of macrophage activation leading to deadly NO, oxidative stress, and cytokine cascade syndrome; the therapeutic effect of MCN seems to be reasonable. Accordingly, a wider clinical trial has been designed. It should be noted that the protocol is using the low-cost drugs which the FDA approved for other diseases. Trial registration number NCT04370288.

Nicotine is a natural component of tobacco plants and is responsible for the addictive properties of tobacco. Nicotine has been recognized to result in oxidative stress by inducing the generation of reactive oxygen species (ROS). The purpose of this work was to estimate the hepatotoxicity effect of nicotine on viability and on antioxidant defense system in cultures of HepG2 cell line and the other hand, ameliorative effect of quercetin (Q) as an antioxidant was analyzed. Nicotine induced concentration dependent loss in HepG2 cell line viability. The results indicated that nicotine decreased activity of superoxide dismutase (SOD) and glutathione reductase (GR) and increased activities of catalase (CAT) and glutathione peroxidase (GPx) and glutathione (GSH) content in the HepG2 cells. Q significantly increased activity of SOD, GR and GSH content and decreased activity of GPX in nicotine + Q groups. Our data demonstrate that Q plays a protective role against the imbalance elicited by nicotine between the production of free radicals and antioxidant defense systems, and suggest that administration of this antioxidant may find clinical application where cellular damage is a consequence of ROS.

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Some types of cancers show a strong relationship with diabetes and play a central role in mortality in the patient population suffering from diabetes mellitus. In this study, HepG2 cells have been used to investigate the toxic effects of hyperglycemia and/or quercetin (Q) on mammalian target of rapamycin (m-TOR) and nuclear factor erythroid 2-related factor 2 (Nrf-2) expression as central molecules involved in cancer. HepG2 cells were cultured with different concentrations of glucose (5.5, 30, and 50 mM) and/or Q (25 µM) for 48 and 72 h. Effects of glucose and/or Q on m-TOR and Nrf-2 expression were assayed by quantitative real-time PCR (qRT-PCR). qRT-PCR results revealed that 30 and 50 mM of glucose increased m-TOR expression at 48 h, although after 72 h, only 30 mM had an increasing effect. At 50 mM, glucose-induced Nrf-2 gene expression after both 48 and 72 h. The results also showed that 25 µM of Q reduced m-TOR and Nrf-2 expression at both 30 and 50 mM after 48 and 72 h incubation. Q has potential effects on reducing oxidative stress caused by hyperglycemia and during diabetes may be able to modulate some carcinogenic signaling pathways.

Introduction: Using image-guided intra-operative navigation systems in surgeries like functional endoscopic sinus surgery (FESS) has become widely accepted as an effective tool for improvement of surgical outcomes and reduction of complication. Cone-beam CT (CBCT) is a variant of computed tomography imaging that has developed as a cross-sectional and potentially low-dose technique to visualize bony structures in the head and neck. In current study, it was tried to evaluate surgeons’ satisfaction with CBCT intra-operative navigation imaging as well as image quality prior to FESS and post-operative complications. Methods: In this prospective study, the included patients who were candidates for FESS underwent CBCT from January to June 2019. The data regarding demographic information, CBCT findings and diagnosis were extracted. The surgeons’ satisfaction with intra-operative navigation imaging and image quality was quantified using Visual Analogue Scale (VAS) (ranging 0 – 10). Furthermore, patients were contacted 3 months later to ask for their satisfaction with the operation using VAS and post-operative complications evaluated. Results: Totally, 39 patients were included. The mean age was 40.74±5.75 and 20 patients (51.28 percent) were male. Two surgeons performed this operation separately; one of the surgeons performed 20 (51.28 percent) FESS and the other performed 19 (48.71 percent). The mean satisfaction of the surgeons of CBCT guided FFESS was 8.69±0.92. After the 3-month  follow up, patients’ satisfaction score was 8.21±1.89. No postoperative complications were reported. Conclusion: Based on the surgeons’ point of view, CBCT was shown to be reliable for image-guided FFESS. Furthermore, the outcome and complications of performed surgeries were similar to those performed with computed tomography intra-operative navigation imaging.