Toxicology and Industrial Health最新文献

This paper provides an overview of airborne methylene diphenyl diisocyanate (MDI) concentrations in workplaces across North America and Europe. A total of 7649 samples were collected between 1998 and 2020 by producers of MDI during product stewardship activities at customer sites, primarily using validated OSHA or ISO sampling and analysis techniques. As would be expected from the low vapor pressure of MDI, 80% of the concentrations were less than 0.01 mg/m³ (1 ppb) and 93% were less than 0.05 mg/m³ (5 ppb). Respiratory protection is an integral part of Industrial Hygiene practices; therefore, its use was studied and summarized. While covering a variety of MDI applications, a large number of samples was obtained from composite wood manufacturing facilities, offering specific insight into potential exposures associated with different process sections and job types in this industry sector. Given the potential presence in industrial processes of MDI-containing dust or aerosols, future work should place increased emphasis on also investigating dermal exposure. The data reported in this paper provide valuable information for product stewardship and industrial hygiene purposes throughout the MDI-processing industry.

Lead (Pb) is a corrosion-resistant, heavy, non-ferrous metal. Several metal chelators have been used for the treatment of Pb poisoning. However, the efficacy of sodium para-aminosalicylic acid (PAS-Na) in enhancing Pb excretion has yet to be fully characterized. Healthy male mice (90) were divided into six groups, the normal control group was intraperitoneally (i.p.) injected with saline and the remaining group of mice i.p. 120 mg/kg Pb acetate. Four hour later, mice were subcutaneously (back) injected (s.c.) with (80, 160, 240 mg/kg) PAS-Na or 240 mg/kg edetate calcium disodium (CaNa₂EDTA) or an equivalent amount of saline, once per day for 6 days. After 24-h urine sample collections, the animals were anesthetized with 5% chloral hydrate and sacrificed in batches on the 2nd, 4th, or 6th day. Levels of Pb [including manganese (Mn) and copper (Cu)] in the urine, whole blood, and brain tissues were analyzed by graphite furnace atomic absorption spectrometry. The results showed that Pb exposure increased its levels in urine and blood, and PAS-Na treatment may afford antagonistic effect on Pb poisoning, suggesting that PAS-Na is a potentially effective treatment to promote excretion of Pb.

The informal aluminum industry is increasingly widespread in low- and middle-income countries, especially in Indonesia. Aluminum exposure is a serious public health problem, especially among workers in the informal aluminum foundry sector. Research on aluminum (Al) is important to advance our understanding of its impact on physiological systems. Here, we investigated the effect of exposure to aluminum longitudinal histological changes on the liver and kidneys of male mice. Mice were separated into six groups (4/group): group 1, group 2, group 3 received vehicles, and group 4, group 5, group 6 were administered a single dose of Al at 200 mg/kg b.w. by intraperitoneally every 3 days for 4 weeks. Post-sacrifice, kidneys and liver were isolated for examination. While Al did not impact the body weight gain of male mice across all groups, it caused liver damage including sinusoidal dilatation, enlarged central veins, vacuolar degeneration, and pyknotic nuclei in one-month-old mice. Furthermore, atrophied glomeruli, blood-filled spaces, and disintegration of renal tubular epithelium are evident at one-month-age. By contrast, sinusoidal dilatation and enlarged central veins were found in mice two- and three-months-old, including hemorrhage in mice (two-month-old) and atrophy of glomeruli. Lastly, the kidneys of three-month-old mice displayed interstitial fibrosis and increasing mesenchyme in the glomeruli. In summary, we demonstrated that Al provoked histological changes in the liver and kidneys with Al-treated 1-month mice being the most susceptible.

One of the major toxic effects of exposure to ammonia is the resulting pulmonary acute and chronic effects. This study investigated the acute pulmonary effects of exposure to ammonia lower than the recommended threshold limit value (TLV). This cross-sectional study was conducted in 2021 in four chemical fertilizer production industries using ammonia as the main raw material. A total of 116 workers who were exposed to ammonia were investigated. The level of exposure to ammonia was measured by NMAM 6016, and the evaluation of pulmonary symptoms and function parameters was done using the American Thoracic Society and European Respiratory Society protocols in four sessions. The paired-sample t-test, repeated measures test, Chi-square, and Fisher's exact test were run to analyze the collected data. The prevalence rates of pulmonary symptoms, including cough, dyspnea, phlegm, and wheezing, were 24.14, 17.24, 14.66, and 16.38%, respectively, after one exposure shift. It was observed that all pulmonary function parameters were reduced after one exposure shift to ammonia. The results revealed that the parameters of vital capacity, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), the FEV1/FVC ratio, and peak expiratory flow significantly decreased (p < 0.05) across four exposure shifts. The findings indicated that exposure to ammonia at concentrations lower than one-fifth of TLV could bring about acute pulmonary effects and reduce pulmonary function parameters, similar to the pattern observed in obstructive pulmonary diseases.

Occupational exposure to respirable crystalline silica (RCS) is common for several occupations in construction, not only because of its presence in many handling materials but also in processes such as grinding and sawing. This study investigated workplace exposure to RCS as quartz in industries and occupations within road construction in Alberta through the RCS monitoring database provided by the Alberta Roadbuilders and Heavy Construction Association (ARHCA) between 2007 and 2016. Descriptive statistics were calculated for exposure-related variables, and mixed model analysis was performed to determine factors affecting the exposure levels. Results showed that the highest exposed workers were in the sand and gravel industry (GM = 45 μg/m³). For worker occupations, geometric means ranged from 78 μg/m³ for crusher operators to 10 μg/m³ for concrete truck operators. The maximum exposure severity was 33.3 times the occupational exposure limit (OEL) for the sand and gravel and 31 times the OEL for tower operators. The results also showed the effect of seasonal variability on RCS exposure levels. The heterogeneous exposure results indicated significant room for improvement and that controls should focus more on the activity performed than the occupation to lower exposure to RCS levels in industries.

The ability of melatonin to reduce growth inadequacy induced by parental and nutritional combination administration to chlorpyriphos (Ch) and cypermethrin (Cy) was examined in male albino rats. Oral alimentation was given to gravid dams divided into six groups (n = 10; age: 12 weeks) from the first day of pregnancy to the 21st postnatal day. Distilled water (D_W), Soya oil (SYO), and melatonin (MeL) groups were exposed to 2 mL/kg, 2 mL/kg, and 0.5 mg/kg, respectively; the Ch+Cy group was co-exposed to Ch (1.9 mg/kg of LD₅₀) and Cy (7.5 mg/kg of LD₅₀); the MChCy group was preconditioned with MeL (0.5 mg/kg), followed by co-exposure to Ch and Cy; and the ChCyM group was exposed to Ch and Cy and post treated with MeL. Male offspring rats were tested for ontogeny criteria at various points after accouchement. MeL pre- and post-administration reduced the variation in litter size and weight, number of live/dead pups, anogenital distance , crown-rump length, the timing of eye and ear openings, and testicular descent caused by fetal and nutritional co-administration to Ch+Cy in offspring male albino rats. MeL demonstrated preventive promise as a result of its apparent antioxidative capability.

High blood levels of lead have been shown to relate to its toxicity, and its early detection in occupational workers is important to take necessary measures. The genes associated with lead toxicity were identified by in silico analysis of expression profile (GEO-GSE37567) based on lead exposure of peripheral blood mononuclear cells maintained in culture. The GEO2R tool was used to identify differentially expressed genes (DEGs) among three groups: control versus day-1 treatment, control versus day-2 treatment, and control versus day-1 treatment versus day-2 treatment, and their enrichment analysis was performed to categorize them for molecular function, biological process, cellular component, and KEGG pathways. The protein-protein interaction (PPI) network of DEGs was constructed using a STRING tool and hub genes were identified by using the CytoHubba plugin of Cytoscape. Top 250 DEGs were screened in the first and second groups and 211 DEGs were in the third group. Fifteen critical genes viz. MT1G, ASPH, MT1F, TMEM158, CDK5RAP2, BRCA2, MT1E, EDNRB, MT1H, KITLG, MT1X, MT2A, ARRDC4, MT1M, and MT1HL1 were selected for functional enrichment and pathway analysis. The DEGs were primarily enriched in metal ion binding, metal absorption, and cellular response to metal ions. The significantly enriched KEGG pathways included mineral absorption, melanogenesis, and cancer signaling pathways. PPI network analysis revealed that seven genes of the MT family exhibited good connectedness and served as a marker of lead induced toxicity. Our study suggests that MT1E, MT1H, MT1G, MT1X, MT1F, MT1M, and MT2A of the metallothioneins gene family may act as potential biomarkers to monitor lead exposure.

Carbon tetrachloride (CCl₄) is a potent liver toxin. Diclofenac (Dic), leading adverse effects on the liver, is used among the employees of the industries that use CCl₄. The increased use of CCl₄ and Dic in industrial workers has prompted us to investigate their synergistic effect on the liver using male Wistar rats as a model. Male Wistar rats were divided into seven groups (n = 6), and the exposure was by intraperitoneal injection for 14 days as follows. Group 1: Control, 2: Olive oil, 3: CCl₄ (0.8 mL/kg/day (3 times per week)), 4: Normal saline, 5: Dic (1.5 mg/kg/day per day), 6: Olive oil with normal saline, 7: CCl₄ (0.8 mL/kg/day (3 times per week)) and Dic (1.5 mg/kg/day daily). At the end of day 14, the heart blood was collected to measure the liver enzymes, alanine-aminotransferase (ALT), aspartate-aminotransferase (AST), blood alkaline phosphatase (ALP), albumin (ALB), direct bilirubin, and total bilirubin. A pathologist examined the liver tissue. Prism software was used to analyze data using ANOVA and Tukey statistical tests. ALT, AST, ALP, and Total Bilirubin enzymes were increased significantly in the co-administered CCl₄ and Dic group, while the ALB levels decreased (p < 0.05). The histological findings reported liver necrosis, focal hemorrhage, adipose tissue change, and lymphocytic portal hepatitis. In conclusion, using Dic while exposed to CCl₄ may exacerbate hepatotoxicity in rats. Therefore, it is suggested that more severe restrictions and safety regulations be placed on using CCl₄ in the industry, and caution is advised to these industry workers to use Diclofenac.

There are various studies on the toxicological potentials of conventionally synthesized zinc oxide (ZnO) nanoparticles, which are useful tools for many medical applications. However, knowledge about the biologically synthesized ones is still limited. In this study, the potential of producing ZnO nanoparticles via a green synthesis method, which enables safer, environmentally, economical and controlled production by using the Symphoricarpos albus L. plant, was investigated. For this purpose, aqueous extract was obtained from the fruits of the plant and reacted with zinc nitrate precursor. Characterization of the synthesized product was carried out by SEM and EDAX analyzes. In addition, the biosafety of the product was also investigated by using the Ames/Salmonella, E. coli WP2, Yeast DEL, seed germination, and RAPD test systems. The results obtained from SEM studies showed that spherical nanoparticles with an average diameter of 30 nm were synthesized as a result of the reaction. EDAX findings confirmed that these nanoparticles were composed of Zn and O elements. On the other hand, according to the findings of the biocompatibility tests, the synthesized nanoparticle did not show any toxic and genotoxic effects up to a concentration of 640 μg/ml in any of the test systems. Accordingly, considering the findings of our study, it was concluded that the aqueous extract of S. albus fruits can be used for the green synthesis of ZnO nanoparticles, the products obtained successfully passed the biocompatibility tests in our study, and additionally, more comprehensive biocompatibility tests should be performed before industrial scale production.

Para-phenylenediamine (PPD) is a derivative of benzene used as an ingredient in dyes, a photographic developing agent, and a component of engineered polymers. The carcinogenicity of PPD, which has been documented in several studies, may be related to its toxic effects on different compartments of the immune system. The main goal of this research was to evaluate the mechanism of the toxicity of PPD on human lymphocytes by exploiting the accelerated cytotoxicity mechanism screening (ACMS) technique. Lymphocytes were isolated from the blood of healthy persons using a Ficoll-Paque PLUS standard method. Assessment of cell viability was carried out 12 h following treatment of human lymphocytes with 0.25-1 mM PPD. For determination of cellular parameters, isolated human lymphocytes were incubated with 1/2 the IC50 (0.4 mM), the IC50 (0.8 mM), and twice the IC50 (1.6 mM) for 2, 4, and 6 h. Half maximal inhibitory concentration (IC50) is the concentration that reduces cell viability approximately 50% following treatment. The results of this study demonstrated that PPD-associated apoptosis in human lymphocytes was mainly through the enhancement of intracellular calcium, oxidative stress, and following adverse effect on lymphocyte organelles (like mitochondria and lysosomes). Lipid peroxidation, activation of caspase-3, and stimulation of cytokines (IL₂, interferon-gamma (IFN-γ), and TNF-alpha) production were also observed in PPD-treated lymphocytes. Considering the results of this study, we can suggest an association between PPD carcinogenicity and its toxic effects on different compartments of the immune system.