Assessment of Thyroid Function and Oxidative Stress State in Foundry Workers Exposed to Lead.

BACKGROUND: Exposure to lead (Pb) has been associated with endocrine, hematological, gastrointestinal, renal and neurological problems in humans. However, effects on the thyroid gland are controversial. OBJECTIVES: The aim of the present study was to assess thyroid function in foundry workers occupationally exposed to Pb and the mechanism of oxidative-antioxidant imbalance. METHODS: Thyroid function parameters and markers of oxidative stress were examined in 59 adult males who had been occupationally exposed to Pb. The results were then compared to those of 28 male subjects who had no history of Pb exposure or thyroid abnormalities and served as a control group. RESULTS: Mean blood lead levels (16.5±1.74 µg/dl) were significantly higher among the exposed workers compared to those of the control group (12.8±1.16 µg/dl, (p <0.001)). The exposed group had significantly increased free triiodothyronine (FT3), free thyroxine (FT4) and significantly decreased thyroid stimulating hormone (TSH) (1.77±0.44 µIU/ml), whereas the control group had a TSH level of 2.61±0.94 µIU/ml (p< 0.0001). A state of oxidative stress was indicated by the significant increase in mean levels of malondialdehyde (MDA) and significant decrease in glutathione (GSH) (p < 0.0001). There was a significant positive correlation (r=0.358, p <0.05) between blood lead levels (BLL) and duration of employment, while BLL showed a significant negative correlation with TSH (r =-0.486, p <0.001), and GSH (r =-0.336, p <0.05). Of the occupationally exposed workers, 32.76% had elevated thyroid hormones. The results showed a significant positive relationship between GSH and TSH (ß coefficient=0.274, p < 0.05), MDA with FT3 (ß coefficient=0.355, p < 0.05) and FT4 (ß coefficient = 0.491, p < 0.0001) among exposed workers. CONCLUSIONS: Workers exposed to Pb dust proved to be at risk for hyperthyroidism, which was found to have a significant role in oxidative-antioxidant imbalance present among workers with increasing duration of exposure. PARTICIPANT CONSENT: Obtained. ETHICS APPROVAL: This study was approved by the Ethical Committee of the National Research Centre in Egypt (NRC) under the registration number 15225. COMPETING INTERESTS: The authors declare no competing financial interests.

In utero exposure to organochlorine pesticide residues and their potential impact on birth outcomes and fetal gender.

Being the largest agriculture country in the Arab world, Egypt was one of the major consumer of organochlorine pesticides (OCPs) in this area, continued to have a heavy burden of OCPs in the environment. There is growing concern that OCPs could pass from the maternal circulation through the placenta to the fetal circulation and pose several health risks to their fetuses. The current study was intended to identify OCPs residue exposure in healthy pregnant women and to justify the potential impacts of these residues on their fetuses. In this study, the prevalence of 18 OCPs was estimated in 81 maternal and cord blood samples, using Agilent 7890, gas chromatograph equipped with micro-electron capture detector (GC-µECD). Our data signposted that the heptachlor epoxide has the highest detection rate among all residues in both maternal (32%) and cord blood serum (27.16%). DDTs were still quantifiable, but with the lowest quantifiable percentage. More than 85% of mothers' serum with detectable residues transfer OCPs residue to their fetuses in a statistically significant manner (x = 42.9, p value < 0.001). The present findings showed no significant growth retardation, or preterm delivery induced by in utero exposure to the most abundant residues. There is growing evidence that exposure to OCPs residue has profound impact on sex ratio. Methoxychlor, in this study be deemed as testosterone triggers which yields high boys ratio (x = 4.37, p < 0.05). In conclusion, Egypt continued to have a heavy burden of OCPs residues, and fetuses and infants are especially the most vulnerable groups to their adverse health effects. Exposure to OCPs may disrupt the maternal hormones, which regulate the offspring gender, but these results need to be validated in larger sample sizes.

Down-regulation of circulating microRNA let-7a in Egyptian smokers.

Altered miRNAs were associated with cigarette smoking. The study aimed to examine the gene expression level of plasma let-7a among healthy smokers and compared it with the non-smokers. Forty subjects were recruited for the present study and classified into 21 smokers and 19 non-smokers, age, and sex were matched. The software that used to design functional primers was MIRprimer. Quantitative real-time PCR was employed to compare the relative expression of plasma let-7a. Results showed that the level of let-7a was down-regulated in smokers to 0.34fold (p = 0.006) that of the non-smokers. Plasma let-7a showed an area under curve (AUC) of 0.749 with sensitivity 43% and specificity 100%. In conclusion, plasma let-7a was significantly down-regulated in the smokers, and it might be considered a candidate biomarker to discriminate between smokers and non-smokers.

Some health effects of aircraft noise with special reference to shift work.

BACKGROUND: Aircraft noise is an environmental stressor. A positive relationship exists between noise and high blood pressure. Shift work is an additional hazardous working condition with negative effect on the behavior attitude of workers. OBJECTIVE: This study aimed at investigating some health hazards for shift work on workers at Cairo International Airport (CIA), Egypt, as a strategic work place, with more than one stressor. SUBJECTS AND METHODS: Assessment of noise effects were carried out in four working sites at the airport besides control sites. The average noise level in the exposure sites was 106.5 dB compared with 54 dB at the control sites. The study comprised a group of 200 male workers exposed to aircraft noise and 110 male workers not exposed to noise as control group. All workers had full general medical examination after filling specially formulated questionnaire. Hearing impairment, raised blood pressure, headaches, disturbed sleep, and symptoms of anxiety were more prominent among the exposed workers than the control. Symptoms of upper respiratory tract were reported among night shifters of both groups with high tendency for smoking. Thus, night-shift workers at CIA work under more than one stressor. Hypertension and smoking might act as intermediate factors on the causal pathway of complaints, making aircraft noise and night shift acting as two synergistic stressors. Airport workers are in need for aggressive hearing conservation programs. Organization of the working hours schedule is mandatory to avoid excessive noise exposure.