Protective effect of ipratropium bromide on bronchoconstriction induced by sulfur dioxide exposure during apricot sufurization processes that causes asthma-like syndrome in agricultural environment

Asthma-prone areas modeling using a machine learning model

Nowadays, owing to population growth, increasing environmental pollution, and lifestyle changes, the number of asthmatics has significantly increased. Therefore, the purpose of our study was to determine the asthma-prone areas in Tehran, Iran considering environmental, spatial factors. Initially, we built a spatial database using 872 locations of children with asthma and 13 environmental factors affecting the disease—distance to parks and streets, rainfall, temperature, humidity, pressure, wind speed, particulate matter (PM 10 and PM 2.5), ozone (O₃), sulfur dioxide (SO₂), carbon monoxide (CO), and nitrogen dioxide (NO₂). Subsequently, utilizing this spatial database, a random forest (RF) machine learning model, and a geographic information system, we prepared a map of asthma-prone areas. For modeling and validation, we deployed 70% and 30%, respectively, of the locations of children with asthma. The results of spatial autocorrelation and RF model showed that the criteria of distance to parks and streets as well as PM 2.5 and PM 10 had the greatest impact on asthma occurrence in the study area. Spatial autocorrelation analyses indicated that the distribution of asthma cases was not random. According to receiver operating characteristic results, the RF model had good accuracy (the area under the curve was 0.987 and 0.921, respectively, for training and testing data).

Genotoxic effects of sulfur dioxide in human lymphocytes

Sulfur dioxide (SO2), which is used as food preservative in apricot sulfurization and several fabricated foods, is a common air pollutant. The aim of this study was to reveal the possible genotoxic effects of SO2 using in vitro human lymphocytes. The different endpoints of genotoxicity: sister chromatid exchange (SCE), micronuclei (MN) tests and cell growth kinetics such as mitotic index (MI) and replication index (RI) were studied. The cells were treated with 0.1, 0.5 and 1.0 ppm concentrations of SO2. It was shown that SO2 caused significant increases in the frequency of SCE and MN in the middle and high dosage groups and also induced mitotic delays and decreased MI and RI. In conclusion, the results have confirmed that SO2 has potent mutagenicity and it can cause genetic damage leading to a malignancy.

Vitamin A deficiency increases airway resistance following C-fiber stimulation

Vitamin A deficiency (VAD) remains an important problem in the developing world where environmental air pollution is increasing. Because the coincidence of these factors could increase the prevalence of asthma in these regions, airway reactivity to methacholine (MCh), capsaicin, and sulfur dioxide was studied in VAD rats. The impedance to a small volume oscillation was analyzed to determine airway resistance (R(aw)) and lung elastance (H). VAD rats demonstrated larger increases in R(aw) and H after the administration of methacholine, and in R(aw) after administration of capsaicin or sulfur dioxide. The muscarinic receptor-2 (M2R) selective antagonist AFDX-116 enhanced the effect of capsaicin in vitamin A sufficient (VAS) but not VAD rats and retinoic acid-administration partially restored this enhancement. These data indicate that diminished auto-inhibitory muscarinic receptor-2 function contributed to this increased airway responsiveness to pulmonary C-fiber stimulation in VAD rats. If children with VAD also have diminished M2R function, they may be more prone to develop asthma, particularly in the presence of environmental co-factors such as sulfur dioxide.