Exposure to Endocrine Disrupting Chemicals and Male Reproductive Health

Endocrine disrupting chemicals (EDCs) can interfere with normal hormonal balance and may exert adverse consequences on humans. The male reproductive system may be susceptible to the effects of such environmental toxicants. This review discusses the recent progress in scientific data mainly from epidemiology studies on the associations between EDCs and male reproductive health and our understanding of possible mechanisms associated with the effects of EDCs on male reproductive health. Finally, the review provides recommendations on future research to enhance our understanding of EDCs and male reproductive health. The review highlights the need for (1) well-defined longitudinal epidemiology studies, with appropriately designed exposure assessment to determine potential causal relationships; (2) chemical and biochemical approaches aimed at a better understanding of the mechanism of action of xenoestrogens with regard to low-dose effects, and assessment of identify genetic susceptibility factors associated with the risk of adverse effects following exposure to EDCs

Influence of Exposure to Benzo[a]pyrene on Mice Testicular Germ Cells during Spermatogenesis

The objective of this study was to assess the toxicological effect of exposure to benzo(a)pyrene, B[a]P, on germ cells during spermatogenesis. Mice were exposed to B[a]P at 1, 10, 50, and 100 mg/kg/day for 30 days via oral ingestion. Germ cells, including spermatogonia, spermatocytes, pachytene spermatocytes, and round spermatids, were recovered from testes of mice exposed to B[a]P, while mature spermatozoa were isolated from vas deferens. Reproductive organs were collected and weighed. Apoptotic response of germ cells and mature spermatozoa were qualified using the terminal deoxynucleotidyl transferase mediated deoxy-UTP nick end labeling (TUNEL) assay. B[a]P exposure a

Bioaerosol Effect on Safe Use of Bathroom Appliances for Drinking Water Consumption

Purpose: The purpose of this study was to assess the bioaerosol effects on the use of bathroom appliances (a fountain faucet and a reusable cup) for drinking water consumption. Methods: A mechanically pressurized hydraulic spray nozzle was used to generate bioaerosols containing non-pathogenic E. coli. These bioaerosols became airborne and came in contact with a fountain faucet (NASONI, Inc.) and a reusable cup. 10 mL and 100 mL of water samples from the cup and the faucet stream, respectively, were collected at intervals of 10 secs, 30 secs, 1 min, 2 mins, and 5 mins. A Tryptic Soy Broth (TSB) liquid solution was used to determine whether E. coli was present in the water, while the Colilert test was conducted to quantify E. coli concentrations. Results: 88 MPN/100 mL – 866 MPN/100 mL of E. coli from the aerosol effect was removed from the fountain stream after the faucet was kept open for 10 secs. However, E. coli continued to be present in the reusable cup over the sampling period. Conclusion: The fountain feature of the faucet had a significantly lower risk of microbial contamination from the aerosol effect as compared with the reusable cup

Urinary DNA Lesions as a Biomarker for Assessing Male Reproductive Health

The study aimed to examine whether urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG) could serve as a biomarker for assessing sperm DNA integrity. Urine and semen samples were collected from 124 coke-oven workers, who had chronically been exposed to polycyclic aromatic hydrocarbons (PAHs), from a steel plant in Kaohsiung, Taiwan. The coke-oven workers were divided into two subgroups: topside-oven workers and side-oven workers. Sperm DNA integrity was assessed in terms of DNA fragmentation and 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodGuo). Urine samples were used to detect 1-hydroxypyrene (1-OHP) and urinary 8-OHdG, which served to assess exposure to PAHs and the whole body oxidative stress, respectively. Urinary 1-OHP concentrations were significantly higher in the topside-oven workers than the side-oven workers (p = 0.02). Sperm 8-oxodGuo concentrations were correlated with percentages of sperm fragmentation (p = 0.044), but urinary 8-OHdG levels failed to correlate with sperm 8-oxodGuo levels and with percentages of fragmentation. In conclusion, exposure to PAHs was linked to increased oxidative stress on sperm. However, urinary 8-OHdG may not be a suitable biomarker for examining sperm DNA damage associated with oxidative stress

Influence of Exposure to Benzo[a]pyrene on Mice Testicular Germ Cells during Spermatogenesis

The objective of this study was to assess the toxicological effect of exposure to benzo(a)pyrene, B[a]P, on germ cells during spermatogenesis. Mice were exposed to B[a]P at 1, 10, 50, and 100 mg/kg/day for 30 days via oral ingestion. Germ cells, including spermatogonia, spermatocytes, pachytene spermatocytes, and round spermatids, were recovered from testes of mice exposed to B[a]P, while mature spermatozoa were isolated from vas deferens. Reproductive organs were collected and weighed. Apoptotic response of germ cells and mature spermatozoa were qualified using the terminal deoxynucleotidyl transferase mediated deoxy-UTP nick end labeling (TUNEL) assay. B[a]P exposure at ≤10 mg/kg/day for 30 days did not significantly alter concentrations of germ cells and mature spermatozoa and apoptotic response in germ cells and mature spermatozoa. Exposure to B[a]P at 50 and 100 mg/kg/day induced testicular atrophy and yielded a significant reduction in the concentrations of spermatogonia, spermatocytes, pachytene spermatocytes, and round spermatid cells as compared with the control. Also, mature spermatozoa experienced decreased concentrations and viability. B[a]P-exposed mice experienced a significant increase in apoptotic germ cells as compared to the control mice. However, the mice dose concentrations were not relevant for comparison to human exposure

Air Quality Monitoring in the Southeast Community in the City of Newport News, VA

Purpose: The objective of this study was to assess air quality in the Southeast Community of Newport News, VA by monitoring air pollutants, including PM2.5, PM10, VOCs, NO2, and SO2. Currently, there is a lack of community specified air quality data in Newport News despite observed environmental degradation and public health problems. Methods: Three air sampling sites were located within residential areas of the Southeast Community, while four industrial air sampling sites were chosen based on proximity to potential pollution sources, including traffic emissions, the coal pier, and industrial activities. All of the industrial sites were located on the boundaries of the community. Each site was continuously monitored for eight hours per day and was sampled at least twice for data accuracy. A GRIMM PM monitor was used to measure PM2.5 and PM10 and a MultiRae PRO (model PGM-6248) was used to continuously quantify VOCs, NO2, and SO2. Results: While average PM2.5 and PM10 from all sample sites were within the acceptable range of EPA air quality criteria, averaged VOCs in the industrial and highway areas were higher than those in the community. Conclusion: The findings of this research suggest a need for long-term monitoring air quality with a series of air pollutants in the community

Arsenic Exposure and Methylation Efficiency in Relation to Oxidative Stress in Semiconductor Workers

This study examined associations between oxidative stress and arsenic (As) exposure and methylation efficiency in semiconductor workers. An As-exposed group (n = 427) and a control group (n = 91) were included. The As-exposure group (n = 427) included 149 maintenance staff members and 278 production staff members representing high As exposure and low As exposure, respectively. The control group included 91 administrative staff members with no or minimal As exposure. An occupational exposure assessment was conducted to assess personal As exposure by measuring As concentrations in urine, hair, and fingernails of the subjects. Urinary As(III), As(V), monomethylarsonic (MMA), and dimethylarsinic acid (DMA) were quantified to assess an internal dose of inorganic As. Urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were measured to asses oxidative DNA damage and lipid peroxidation, respectively. As concentrations in urine, hair, and fingernails significantly increased (p \u3c 0.05) in the As-exposed group in comparison to the control group. Geometric mean urinary concentrations of As, 8-OHdG, and MDA in the As-exposed group significantly exceeded those in the control group. As exposure to As-exposed workers had increased concentrations of 8-OHdG in contrast to those in control subjects. Moreover, urinary 8-OHdG concentrations in the semiconductor workers were positively correlated with urinary total As metabolite (As(III) + As(V) + MMA + DMA) concentrations. Furthermore, urinary excretion of 8-OHdG concentrations in As-exposed workers were positively associated with urinary excretion of MMA concentrations and primary methylation index values (the ration of MMA/inorganic As). However, fingernail and hair samples did not perform as well as urinary samples to measure oxidative stress induced by As exposure. 8-OHdG could serve as a more reliable biomarker for assessing As methylation than MDA did. Occupational exposure to inorganic As was associated with increased oxidative stress among semiconductor workers

Modeling the Spread of COVID-19 in Spatio-Temporal Context

This study aims to use data provided by the Virginia Department of Public Health to illustrate the changes in trends of the total cases in COVID-19 since they were first recorded in the state. Each of the 93 counties in the state has its COVID-19 dashboard to help inform decision makers and the public of spatial and temporal counts of total cases. Our analysis shows the differences in the relative spread between the counties and compares the evolution in time using Bayesian conditional autoregressive framework. The models are built under the Markov Chain Monte Carlo method and Moran spatial correlations. In addition, Moran\u27s time series modeling techniques were applied to understand the incidence rates. The findings discussed may serve as a template for other studies of similar nature

Impact of Heavy Metals in Ambient Air in Insulin Resistance of Shipyard Welders in Northern Taiwan

Exposure to metals poses potential health risks, including insulin resistance (IR), to those exposed to them in excess. Limited studies have examined such risks in occupational workers, including welders, and these have yielded inconsistent results. Thus, we examined the associations between exposure to welding metals and IR in welders. We recruited 78 welders and 75 administrative staff from a shipyard located in northern Taiwan. Personal exposure to heavy metals, including chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd), was monitored through particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5) and urine analysis by inductively coupled plasma mass spectrometry (ICP–MS). After each participant fasted overnight, blood samples were collected and analyzed for IR assessment through updated homeostasis model assessment (HOMA2) modeling. Air sampling in the personal breathing zone was performed during a Monday shift prior to the blood and urine sample collection the following morning. The welders’ median personal Cr, Mn, Fe, Ni, Cu, and Zn airborne PM2.5 levels and urinary Cd levels were significantly higher than those of the administrative staff. After adjustment for covariates, logarithmic PM2.5-Mn, PM2.5-Fe, PM2.5-Cu, and PM2.5-Zn levels were positively correlated with logarithmic fasting plasma glucose (P-FGAC) levels (PM2.5-Mn: β = 0.0105, 95% C.I.: 0.0027–0.0183; PM2.5-Fe: β = 0.0127, 95% C.I.: 0.0027–0.0227; PM2.5-Cu: β = 0.0193, 95% C.I.: 0.0032–0.0355; PM2.5-Zn: β = 0.0132, 95% C.I.: 0.0005–0.0260). Logarithmic urinary Zn was positively correlated with logarithmic serum insulin and HOMA2-IR levels and negatively correlated with logarithmic HOMA2-insulin sensitivity (%S; βinsulin = 0.2171, 95% C.I.: 0.0025–0.4318; βIR = 0.2179, 95% C.I.: 0.0027–0.4330; β%S = −0.2180, 95% C.I.: −0.4334 to −0.0026). We observed that glucose homeostasis was disrupted by Mn, Fe, Cu, and Zn exposure through increasing P-FGAC and IR levels in shipyard welders