Some altered concentrations of elements in semen of workers exposed to trinitrotoluene

Transgenerational reproductive toxicity of 2,4,6-trinitrotoluene (TNT) and its metabolite 4-ADNT in Caenorhabditis elegans

2,4,6-trinitrotoluene (TNT) as an energetic compound widely used in military applications has aroused great concerns in recent years due to its large-scale contamination in soil and water; however, its toxicity is still largely unknown. In this study, we investigated the reproductive toxicity and the transgenerational effects of TNT on Caenorhabditis elegans (C. elegans). Our data showed that exposure to TNT at concentrations ranging from 10 to 100 ng/mL resulted in decreasing the lifespan, brood size, number of oocytes and eggs in uterus, while increasing the number of germ cell apoptosis in C. elegans. The apoptotic effects of TNT were blocked in mutants of cep-1 (w40), egl-1 (n487), and hus-1 (op241), indicating conserved genotoxic response genes was involved in mediating TNT-induced germ cell apoptosis. Parental exposure to TNT significantly increased the germ cell apoptosis from P0 to F2 generation, but the toxicity faded away in F3 and F4 generations. Furthermore, TNT was rapidly metabolized in P0, and the accumulation of 4-aminodinitrotoluene (4-ADNT), the main metabolite of TNT in C. elegans, showed a significant decrease from P0 to F1 and a slow decrease in the subsequent generations. Our results demonstrated that ingested TNT can cause severe transgenerational reproductive toxicity and be rapidly converted to 4-ADNT in the nematodes. These data provided basis for future studies on the effects of energetic compounds across generations.

Lead, selenium and nickel concentrations in epithelial ovarian cancer, borderline ovarian tumor and healthy ovarian tissues

OBJECTIVE

Wide variation exists in ovarian cancer incidence rates suggesting the importance of environmental factors. Due to increasing environmental pollution, trace elements and heavy metals have drawn attention in studies defining the etiology of cancer, but scant data is available for ovarian cancer. Our aim was to compare the tissue concentrations of lead, selenium and nickel in epithelial ovarian cancer, borderline tumor and healthy ovarian tissues.

METHODS

The levels of lead, selenium and nickel were estimated using atomic absorption spectrophotometry in formalin-fixed paraffin-embedded tissue samples. Tests were carried out in 20 malignant epithelial ovarian cancer, 15 epithelial borderline tumor and 20 non-neoplastic healthy ovaries. Two samples were collected for borderline tumors, one from papillary projection and one from the smooth surface of cyst wall.

RESULTS

Pb and Ni concentrations were found to be higher both in malignant and borderline tissues than those in healthy ovaries. Concentrations of Pb and Ni in malignant tissues, borderline papillary projections and capsular tissue samples were not different. Comparison of Se concentrations of malignant, borderline and healthy ovarian tissues did not reveal statistical difference. Studied metal levels were not found to be different in either papillary projection or in cyst wall of the borderline tumors.

CONCLUSIONS

This study revealed the accumulation of lead and nickel in ovarian tissue is associated with borderline and malignant proliferation of the surface epithelium. Accumulation of these metals in epithelial ovarian cancer and borderline ovarian tumor has not been demonstrated before.

Impact of ammunition and military explosives on human health and the environment

OBJECTIVE

To review the literature concerning the risks associated with the main xenobiotics contained in military ammunition and explosive residues and damage to human and environmental health.

METHODOLOGY

Using "ammunition", "military", "environmental", "health", "explosive", "metal", "TNT", "RDX", "pollution", and "contamination" as search terms, a large database, namely ISI Web of Knowledge and PubMed, was searched for studies on military ammunition and explosive residues from 1989 to 2010. Other sources used to conduct the search included the library of the Toxicology Laboratory of the Center for Workers' Health and Human Ecology (CESTEH) at the National School of Public Health.

RESULTS

In total, 15 different combinations were used with the search words above and 708 papers were found. Among them, 76 papers concerned this review. More than 12 references of interest were discovered in the library of the CESTEH. The results were organized into metals, dinitrotoluene, trinitrotoluene (TNT), and royal demolition explosive (RDX), showing their main uses, occurrence in the environment, the current toxic effects to human and environmental health, and remediation possibilities.

CONCLUSION

Because military activities can cause the acute and chronic exposure of human beings, the public administration must aim politics towards suitable environmental management.

Expression of steroidogenic acute regulatory protein (StAR) in male American bullfrog (Rana catesbeiana) and preliminary evaluation of the response to TNT

We examined the expression of steroidogenic acute regulatory (StAR) protein mRNA in the American bullfrog (Rana catesbeiana). Primers and probes were designed to obtain a partial sequence of bullfrog StAR cDNA consisting of 349 base pairs. Quantitative PCR analysis of StAR mRNA equivalents was performed in tissues of juvenile and adult bullfrogs. In this study 18S mRNA was used as an internal standard. There were no differences in the expression of 18S RNA among tissues or between age groups. In juvenile males, the rank order for the constitutive levels of StAR was testes>skin>brain>kidneys. In adult males, StAR mRNA equivalent was greatest in testes, followed by kidneys, brain, and skin. In addition, stimulation and induction of testicular StAR by human chorionic gonadotropin significantly increased expression of StAR at 2, 4, and 6h after injection. Preliminary evaluation of 2, 4, 6-trinitrotoluene (TNT) revealed that acute exposure is associated with reduction of StAR mRNA expression. The information provided in this study will be useful for future research on StAR gene expression in amphibian reproductive biology and the development of reproductive biomarkers.

The androgen-regulated epididymal sperm-binding protein, human beta-defensin 118 (DEFB118) (formerly ESC42), is an antimicrobial beta-defensin

Spermatozoa bind a variety of proteins as they pass through the proximal regions of the epididymis, where they acquire forward motility and fertilizing ability. Recent evidence indicates that certain epididymis-specific secretory proteins that bind sperm have antibacterial activity and may function as part of the innate immune system. We reported earlier that ESC42, now designated human beta-defensin 118 (DEFB118), is a sperm-binding protein. In this study, we demonstrate that DEFB118 has potent antibacterial activity that is dose, time, and structure dependent. Incubation of Escherichia coli for 60 min with 10 microg/ml DEFB118 reduced bacterial survival to 20% of the control, and 25 microg/ml reduced survival to 5% of the control. DEFB118 concentrations of 50 and 100 microg/ml further reduced survival to less than 2 and 1%, respectively. A biphasic effect of salt concentration on the antibacterial activity of DEFB118 was observed. Reduction of disulfide bonds and alkylation of cysteines resulted in the complete loss of antibacterial activity. DEFB118 caused rapid permeabilization of both outer and inner membranes of E. coli and striking morphological alterations in the bacterial surfaces visible by scanning electron microscopy consistent with a membrane-disruptive mechanism of bacterial killing. In contrast, eukaryotic cell membranes were not permeabilized by DEFB118, as indicated by the rat erythrocyte hemolytic assay. Studies on DEFB118 inhibition of macromolecular synthesis and membrane permeability in E. coli were consistent with a primary effect at the cell membrane level. DEFB118 may contribute to epididymal innate immunity and protect the sperm against attack by microorganisms in the male and female reproductive tracts.

Exposure to nitroaromatic explosives and health effects during disposal of military waste

AIMS

To investigate the exposure to dinitrotoluene (DNT) and trinitrotoluene (TNT) and the resulting effects in workers which occur during the disposal of military waste.

METHODS

Eighty two employees from a mechanical plant in Germany were studied, of whom 51 were regularly exposed to ammunition containing TNT and DNT, 19 occasionally, and 12 not at all.

RESULTS

Air analyses yielded maximum concentrations of 20 micro g/m(3) for 2,4-DNT and 3250 micro g/m(3) for 2,4,6-TNT, respectively. The maximum concentrations in the urine of workers regularly exposed amounted to 5.0 micro g/l of 2,4,6-TNT, 1464.0 micro g/l of 2-amino-4,6-dinitrotoluene, 6693.0 of micro g/l 4-amino-2,6-dinitrotoluene, 2.1 micro g/l of 2,4-DNT, 95.0 micro g/l of 2,4-dinitrobenzoic acid, and 3.6 micro g/l of 2,6-DNT. There was a highly significant linear correlation between the urinary concentrations of the two main metabolites of TNT, 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene. In 63 persons TNT or DNT or metabolite concentrations above the analytical detection limit were found in urine. These persons reported more frequently symptoms like bitter taste, burning eyes, and discoloration of the skin and hair than persons (n = 19) without detectable TNT and/or DNT exposure.

CONCLUSION

During the disposal of military waste containing relevant TNT and DNT, exposure can occur of occupational-medical relevance. Biological monitoring is suitable for the early detection of possible adverse effects at workplaces exposed to TNT. Protective measures should be improved, together with adequate occupational-medical surveillance of persons exposed to nitroaromatic explosives. Further studies are necessary to exclude possible long term effects.

Biomarkers for male reproductive health hazards: are they available?

This review aims to give an overview of some of the biomarkers that have been used for the monitoring of human exposure to xenobiotics as well as to provide a summary of some of the recent epidemiological studies on male reproductive health of exposure to environmental and occupational toxicants. Possible molecular mechanisms on seminal quality change are also suggested. Studies using various biomarkers have no doubt enabled us to better characterize the effect of environmental pollutants on the male reproductive system. However, the sensitivity and specificity of these biomarkers have not been comprehensively validated. Furthermore, many epidemiological findings are difficult to replicate owing to the inherited methodological problems of male reproductive health investigations, such as the small number of study subjects, low compliance rate, substantial intra-individual variability in semen parameters, measurement techniques and misclassifications based on single assay. Oxidative damage, in particular DNA-damage caused by free radicals, generated either by xenobiotics, or endogenously, is now thought to be a key molecular mechanism associated with semen quality and sperm function. Laboratory studies and epidemiological findings have suggested that the male reproductive system is susceptible to reactive oxygen species (ROS). On the other hand, there is so far no single all-encompassing biomarker of reproductive capacity in men. A panel of biomarkers with specific goals should be considered. Collaborative multidisciplinary studies are also needed to overcome some of the issues mentioned here.