Correction to: Silent hypoxia: higher NO in red blood cells of COVID-19 patients.

An amendment to this paper has been published and can be accessed via the original article.

Silent hypoxia: higher NO in red blood cells of COVID-19 patients.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) has spread to almost 100 countries, infected over 31 M patients and resulted in 961 K deaths worldwide as of 21st September 2020. The major clinical feature of severe COVID-19 requiring ventilation is acute respiratory distress syndrome (ARDS) with multi-functional failure as a result of a cytokine storm with increased serum levels of cytokines. The pathogenesis of the respiratory failure in COVID-19 is yet unknown, but diffuse alveolar damage with interstitial thickening leading to compromised gas exchange is a plausible mechanism. Hypoxia is seen in the COVID-19 patients, however, patients present with a distinct phenotype. Intracellular levels of nitric oxide (NO) play an important role in the vasodilation of small vessels. To elucidate the intracellular levels of NO inside of RBCs in COVID-19 patients compared with that of healthy control subjects. METHODS: We recruited 14 COVID-19 infected cases who had pulmonary involvement of their disease, 4 non-COVID-19 healthy controls (without pulmonary involvement and were not hypoxic) and 2 hypoxic non-COVID-19 patients subjects who presented at the Masih Daneshvari Hospital of Tehran, Iran between March-May 2020. Whole blood samples were harvested from patients and intracellular NO levels in 1 × 106 red blood cells (RBC) was measured by DAF staining using flow cytometry (FACS Calibour, BD, CA, USA). RESULTS: The Mean florescent of intensity for NO was significantly enhanced in COVID-19 patients compared with healthy control subjects (P ≤ 0.05). As a further control for whether hypoxia induced this higher intracellular NO, we evaluated the levels of NO inside RBC of hypoxic patients. No significant differences in NO levels were seen between the hypoxic and non-hypoxic control group. CONCLUSIONS: This pilot study demonstrates increased levels of intracellular NO in RBCs from COVID-19 patients. Future multi-centre studies should examine whether this is seen in a larger number of COVID-19 patients and whether NO therapy may be of use in these severe COVID-19 patients.

The effect of acetazolamide on the improvement of central apnea caused by abusing opioid drugs in the clinical trial.

PURPOSE: Acetazolamide is utilized as a treatment which falls effective in treating some type of CSA. Hence, it might be effective as far as opium addicts who suffer from CSA are concerned. MATERIALS AND METHOD: The current study was a double-blind, placebo-controlled, cross-over study ( clinicalTrials.gov ID: NCT02371473). The whole procedures were identical for both placebo and acetazolamide phases of clinical research. There were 14 CSA more than 5/h and more than 50% of apnea-hypopnea index (AHI). Out of these 14 patients, 10 volunteered to participate in the study. Fast Fourier transformation was used to separate heart rate variability (HRV) into its component VLF (very low frequency band), LF (low frequency band), and HF (high frequency band) rhythms that operate within different frequency ranges. RESULT: There are significant results in terms of decreased mix apnea and central apnea together due to acetazolamide compared with placebo (P < 0.023). Time of SatO2 < 90% is decreased as well (P < 0.1). There is also decrease of SDNN and NN50 after treatment with acetazolamide respectively (P < 0.001). Regarding fast Fourier transformation, there is increase of pHF and decrease of pLF after acetazolamide treatment (P < 0.001). CONCLUSION: Acetazolamide seems to be effective in improving oxygenation and a decrease of mixed and central apnea events together. In HRV analysis section, LF power has decreased significantly, which may more likely improve prognosis of the patients.

Correction to: Exhaled nitric oxide is not a biomarker for idiopathic pulmonary arterial hypertension or for treatment efficacy.

Following publication of the original article [1], the authors flagged that name of the author 'Batoul Khoundabi' had been provided with an incorrect spelling: 'Batoutl' was given in place of 'Batoul'.

Exhaled nitric oxide is not a biomarker for idiopathic pulmonary arterial hypertension or for treatment efficacy.

BACKGROUND: Idiopathic pulmonary arterial hypertension (IPAH) is a fatal illness. Despite many improvements in the treatment of these patients, there is no unique prognostic variable available to track these patients. The aim of this study was to evaluate the association between fractional exhaled nitric oxide (FeNO) levels, as a noninvasive biomarker, with disease severity and treatment outcome. METHODS: Thirty-six patients (29 women and 7 men, mean age 38.4 ± 11.3 years) with IPAH referred to the outpatient's clinic of Masih Daneshvari Hospital, Tehran, Iran, were enrolled into this pilot observational study. Echocardiography, six-minute walking test (6MWT), FeNO, brain natriuretic peptide (BNP) levels and the functional class of patients was assessed before patients started treatment. Assessments were repeated after three months. 30 healthy non-IPAH subjects were recruited as control subjects. RESULTS: There was no significant difference in FeNO levels at baseline between patients with IPAH and subjects in the control group. There was also no significant increase in FeNO levels during the three months of treatment and levels did not correlate with other disease measures. In contrast, other markers of disease severity were correlated with treatment effect over the three months. CONCLUSION: FeNO levels are a poor non-invasive measure of IPAH severity and of treatment response in patients in this pilot study.

Nutrition and lung cancer: a case control study in Iran.

BACKGROUND: Despite many prospective and retrospective studies about the association of dietary habit and lung cancer, the topic still remains controversial. So, this study aims to investigate the association of lung cancer with dietary factors. METHOD: In this study 242 lung cancer patients and their 484 matched controls on age, sex, and place of residence were enrolled between October 2002 to 2005. Trained physicians interviewed all participants with standardized questionnaires. The middle and upper third consumer groups were compared to the lower third according to the distribution in controls unless the linear trend was significant across exposure groups. RESULT: Conditional logistic regression was used to evaluate the association with lung cancer. In a multivariate analysis fruit (Ptrend < 0.0001), vegetable (P = 0.001) and sunflower oil (P = 0.006) remained as protective factors and rice (P = 0.008), bread (Ptrend = 0.04), liver (P = 0.004), butter (Ptrend = 0.04), white cheese (Ptrend < 0.0001), beef (Ptrend = 0.005), vegetable ghee (P < 0.0001) and, animal ghee (P = 0.015) remained as risk factors of lung cancer. Generally, we found positive trend between consumption of beef (P = 0.002), bread (P < 0.0001), and dairy products (P < 0.0001) with lung cancer. In contrast, only fruits were inversely related to lung cancer (P < 0.0001). CONCLUSION: It seems that vegetables, fruits, and sunflower oil could be protective factors and bread, rice, beef, liver, dairy products, vegetable ghee, and animal ghee found to be possible risk factors for the development of lung cancer in Iran.

Opium could be considered an independent risk factor for lung cancer: a case-control study.

BACKGROUND: Lung cancer is the leading cause of cancer-related death worldwide, and half of all incident lung cancers are believed to occur in the developing countries, including Iran. OBJECTIVE: We investigated the association of opium with the risk of lung cancer in a case-control study. METHODS: We enrolled 242 cases and 484 matched controls in this study. A questionnaire was developed, containing questions on basic demographic characteristics, as well as lifelong history of smoking cigarettes, exposure to passive smoking, opium use and alcohol consumption. For smoking cigarettes and opium and also oral opium intake frequency, duration and cumulative use were categorized into three groups: no use, low use and high use. Conditional logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Multivariate analysis in men showed that after adjusting for the effect of ethnicity, education and pack years of smoking cigarettes, smoking opium remained as a significant independent risk factor with an OR of 3.1 (95% CI 1.2-8.1). In addition, concomitant heavy smoking of cigarettes and opium dramatically increased the risk of lung cancer to an OR of 35.0 (95% CI 11.4-107.9). CONCLUSION: This study demonstrated that smoking opium is associated with a high risk of lung cancer as an independent risk factor.

Diagnostic yield of post-bronchoscopy sputum smear in pulmonary tuberculosis.

BACKGROUND: The early definitive diagnosis of pulmonary tuberculosis (TB) is important for control of the disease in the community. We performed this study to evaluate the additional gain of post-bronchoscopy sputum in the diagnosis of pulmonary TB. METHODS: Bronchoscopy and bronchoalveolar lavage were performed for 126 patients suspected of pulmonary TB who either had 3 negative sputum smears for acid-fast bacilli or could not expectorate. After bronchoscopy the patients were asked to give sputum samples for 3 consecutive days. All of the obtained specimens were investigated for Mycobacterium tuberculosis by smear and culture. RESULTS: Pulmonary TB was confirmed in 56 patients. Among all confirmed cases, the sensitivity of bronchoalveolar lavage smear was 57.1% (32 of 56), sensitivity of post-bronchoscopy smear was 76.7% (43 of 56), and the yield of a combination of the 2 methods was 83.9% (47 of 56). Results of post-bronchoscopy sputum smears were not significantly related to sex, age, human immunodeficiency virus (HIV) infection, presence of cavitary lesions on chest X-ray, or the ability to expectorate before bronchoscopy (p > 0.05). CONCLUSION: Evaluation of post-bronchoscopy sputum smears is helpful for earlier diagnosis of pulmonary TB and is an inexpensive and accessible assay.

Environmental risk factors for lung cancer in Iran: a case-control study.

BACKGROUND: Lung cancer remains the leading cause of cancer death in the world. In Iran, lung cancer is one of the five leading tumours and its incidence has been increasing steadily in both men and women. There is a paucity of data from Iran on risk factors for lung cancer. We evaluated environmental risk factors for lung cancer in a case-control study in five hospitals of Tehran. METHODS: Between October 2002 and October 2005, 242 (178 male, 64 female) patients with histologically confirmed lung cancer and two controls for each patient (242 hospital controls and 242 visiting healthy controls) matched for age, sex and place of residence were interviewed using a structured questionnaire on potential risk factors for lung cancer, including environmental and occupational exposures. Associations between risk factors and lung cancer were assessed using conditional logistic regression. RESULTS: Smokers were 66.5% of all cases (85.4% of men and 14.1% of women) and smoking was the strongest correlate of lung cancer in multivariate analysis [odds ratio (OR) 5.4, 95% confidence interval (CI) 3.2-8.9]. Occupational exposures to inorganic dusts (OR 4.2, 95% CI 2.8-6.7), chemical compounds (OR = 3.4, 95% CI 2.1-5.6) and heavy metals (OR 3.0, 95% CI 1.3-7.0) were also independent risk factors for lung cancer. CONCLUSIONS: In our study, smoking was the principal risk factor for lung cancer. However, preventable exposures in the environment, including occupational settings, should not be ignored.