Developmental and reproductive effects of chemicals associated with unconventional oil and natural gas operations

Unconventional oil and gas (UOG) operations have the potential to increase air and water pollution in communities located near UOG operations. Every stage of UOG operation from well construction to extraction, operations, transportation, and distribution can lead to air and water contamination. Hundreds of chemicals are associated with the process of unconventional oil and natural gas production. In this work, we review the scientific literature providing evidence that adult and early life exposure to chemicals associated with UOG operations can result in adverse reproductive health and developmental effects in humans. Volatile organic compounds (VOCs) [including benzene, toluene, ethyl benzene, and xylene (BTEX) and formaldehyde] and heavy metals (including arsenic, cadmium and lead) are just a few of the known contributors to reduced air and water quality that pose a threat to human developmental and reproductive health. The developing fetus is particularly sensitive to environmental factors, which include air and water pollution. Research shows that there are critical windows of vulnerability during prenatal and early postnatal development, during which chemical exposures can cause potentially permanent damage to the growing embryo and fetus. Many of the air and water pollutants found near UOG operation sites are recognized as being developmental and reproductive toxicants; therefore there is a compelling need to increase our knowledge of the potential health consequences for adults, infants, and children from these chemicals through rapid and thorough health research investigation.

[Citalopram taken during pregnancy and the child born with Hirschsprung's disease]

A woman treated with citalopram during the entirety of her pregnancy bore a child with Hirschsprung's disease. Theories on the development of the enteric nervous system support a possible negative effect of SSRI usage. Epidemiological studies confirm a correlation between pregnant women's use of SSRIs and congenital malformations of their children's digestive system, but not specifically Hirschsprung's disease. Certain limitations in these studies might explain this lack of specificity.

Polybrominated diphenyl ethers affect the reproduction and development, and alter the sex ratio of zebrafish (Danio rerio)

Polybrominated diphenyl ethers (PBDEs) have been commonly used as flame retardants and now become ubiquitous in the global environment. Using zebrafish as a model, we tested the hypothesis that PBDEs may affect the reproduction and development of fish. Zebrafish were exposed to environmentally relevant concentrations of DE-71 (a congener of PBDE commonly found in the environment) throughout their whole life cycle, and the effects of DE-71 on gonadal development, gamete quality, fertilization success, hatching success, embryonic development and sex ratio were investigated. Despite gonadal development was enhanced, reductions in spawning, fertilization success, hatching success and larval survival rate were evident, while significant increases in malformation and percentage of male were also observed in the F1 generation. Our laboratory results suggest that PBDEs may pose a risk to reproductive success and alter the sex ratio of fish in environments highly contaminated with PBDEs.

Use of decongestants during pregnancy and the risk of birth defects

Previous studies suggested that early pregnancy exposure to specific oral decongestants increases the risks of several birth defects. Using January 1993-January 2010 data from the Slone Epidemiology Center Birth Defects Study, we tested those hypotheses among 12,734 infants with malformations (cases) and 7,606 nonmalformed control infants in the United States and Canada. Adjusted odds ratios and 95% confidence intervals were estimated for specific birth defects, with controlling for potential confounders. Findings did not replicate several hypotheses but did support 3 previously reported associations: phenylephrine and endocardial cushion defect (odds ratio = 8.0; 95% confidence interval: 2.5, 25.3; 4 exposed cases), phenylpropanolamine and ear defects (odds ratio = 7.8; 95% confidence interval: 2.2, 27.2; 4 exposed cases), and phenylpropanolamine and pyloric stenosis (odds ratio = 3.2; 95% confidence interval: 1.1, 8.8; 6 exposed cases). Hypothesis-generating analyses involving multiple comparisons identified a small number of associations with oral and intranasal decongestants. Accumulating evidence supports associations between first-trimester use of specific oral and possibly intranasal decongestants and the risk of some infrequent specific birth defects.

Fetal safety of macrolides

Macrolide antibiotics are largely used in pregnancy for different bacterial infections. Their fetal safety has been studied by several groups, yielding opposing results. In particular, there have been studies claiming an association between macrolides and cardiovascular malformations. Exposure in early infancy has been associated with pyloric stenosis and intussusception. This has led to an avoidance in prescribing macrolides to pregnant women in several Scandinavian countries. The Objectives of the present study was to investigate the fetal safety of this class of drug by linking a large administrative database of drug dispensing and pregnancy outcome in Southern Israel. A computerized database of medications dispensed from 1999 to 2009 to all women registered in the Clalit health maintenance organization in southern Israel was linked with two computerized databases containing maternal and infant hospitalization records. Also, medical pregnancy termination data were analyzed. The following confounders were controlled for: maternal age, ethnicity, maternal pregestational diabetes, parity, and the year the mother gave birth or went through medical pregnancy termination. First- and third-trimester exposures to macrolide antibiotics as a group and to individual drugs were analyzed. During the study period there were 105,492 pregnancies among Clalit women that met the inclusion criteria. Of these, 104,380 ended in live births or dead fetuses and 1,112 in abortion due to medical reasons. In the first trimester of pregnancy, 1,033 women were exposed to macrolides. There was no association between macrolides and either major malformations [odds ratio (OR), 1.08; 95% confidence interval (CI), 0.84 to 1.38)] or specific malformations, after accounting for maternal age, parity, ethnicity, prepregnancy diabetes, and year of exposure. During the third trimester of pregnancy, 959 women were exposed to macrolides. There was no association between such exposure and perinatal mortality, low birth weight, low Apgar score, or preterm delivery. Similarly, no associations were demonstrated with pyloric stenosis or intussusception. Use of macrolides in the first trimester of pregnancy is not associated with an increased risk of major malformations. Exposure in the third trimester is not likely to increase neonatal risks for pyloric stenosis or intussusception in a clinically meaningful manner.

Reproductive and genotoxic effects in zebrafish after chronic exposure to methyl methanesulfonate in a multigeneration study

There is still controversy whether adverse effects by genotoxic anthropogenic pollutants are linked to the decline of fish populations. Further investigations into the relationship between genotoxic stress and detrimental effects on development and reproduction in fish are required. For this end, zebrafish (F0 generation) were exposed in vivo to the alkylating model genotoxin methyl methanesulfonate (MMS) from fertilization to the age of 1 year. F0 fish were mated over 6 months to check for reproductive capacities. F1 fish grew up without exposure in order to allow for regeneration. Mortality of F0 fish depended on MMS concentrations. In MMS-exposed F0 fish, times of first spawning were delayed and fertility was reduced. Using the alkaline comet assay and the micronucleus test, significant genotoxic effects were found in the livers, gills and gonads of either sex in the F0 generation. No detrimental effects on growth were found. In F1 fish with parental exposure, teratogenic effects were increased, and larval survival was reduced. However, fertility capacities of the non-exposed F1 generation had recovered. Development and survival rates further recovered in the F2 generation. Anthropogenic genotoxicants may thus play a considerable role in the decline of wild fish populations.

Parental exposure to methyl methane sulfonate of three-spined stickleback: contribution of DNA damage in male and female germ cells to further development impairment in progeny

Data regarding the link between DNA integrity of germ cells and the quality of progeny in fish exposed to genotoxicant are scarce although such information is of value to understand genotoxic effects of contaminants in aquatic fauna. This work aimed at studying the consequences of a parental exposure during the breeding season on offspring quality in three-spined stickleback. After in vivo exposure of adult fish to methyl methane sulfonate, a model alkylating compound, a clear increase in DNA damage was observed in erythrocytes of both genders, here used as a biomarker of exposure. MMS exposure significantly affected sperm DNA integrity but neither female fecundity nor fertilization success. In order to understand the contribution of each sex to potential deleterious effects in progeny due to parental exposure, mating of males and females exposed or not to MMS, was carried out. Exposure of both males and females or of males alone led to a significant increase in both mortality during embryo-larval stages and abnormality rate at hatching that appeared to be sensitive stages. Thus, in accordance with recent studies carried out in other freshwater fish species, such development defects in progeny were clearly driven by male genome, known to be devoid of DNA repair capacity in spermatozoa. The next step will be to investigate the link between DNA damage in stickleback sperm and reproductive impairment in natural populations exposed to complex mixture of genotoxicants.

Possible association between maternal lithium therapy and premature closure of the arterial duct. A case report

BACKGROUND

Frequent causes of premature ductal closure include spontaneous idiopathic closure in utero and maternal use of nonsteroidal anti-inflammatory drugs late in pregnancy.

CASE

We describe a case of a preterm infant born to a mother treated with lithium throughout pregnancy who presented with right-sided cardiac enlargement at 18 weeks' gestation. Immediately following delivery, echocardiography demonstrated a small closing patent arterial duct.

CONCLUSION

We recommend that serial fetal echocardiography with emphasis on Doppler interrogation of the patent arterial duct be performed whenever a pregnant woman is taking lithium. The interrogation of the patent arterial duct is particularly important if right-sided chamber enlargement is noted at fetal sonography as this finding can be an early manifestation of premature ductal constriction.

Prenatal and developmental effect of high molecular weight chitosan (HMWCS) to mice

High molecular weight chitosan (HMWCS) is effective at hemostasis and wound healing, and will be potentially used on injured internal organs. To study its prenatal and developmental effect in vivo, forty-four ICR pregnant mice per group were singly injected intraperitoneally at 0, 125, 500 or 2000 mg/kg body weight, respectively, on gestation day 6 (GD6). Clinical signs, reproductive capacity, fetus and infant developments, and histopathological changes were then observed. The results showed that the treatment of HMWCS could decrease body weights and food consumptions, and induce diarrhea, vaginal bleeding, and some other adverse effects in F0 mice. For the emaciation and threatened abortion of pregnant mice, the numbers of live fetuses and early resorption were reduced significantly in HMWCS groups. However, the developments of F1 and F2 mice were not affected, except for lower weights of the body and some organs. In addition, the NOAEL of HMWCS in maternal toxicity was considered to be less than 125 mg/kg, and the NOAEL in developmental toxicity was 125 mg/kg.

The impact of incinerators on human health and environment

Of the total wastes generated by health-care organizations, 10%-25% are biomedical wastes, which are hazardous to humans and the environment and requires specific treatment and management. For decades, incineration was the method of choice for the treatment of such infectious wastes. Incinerator releases a wide variety of pollutants depending on the composition of the waste, which leads to health deterioration and environmental degradation. The significant pollutants emitted are particulate matter, metals, acid gases, oxides of nitrogen, and sulfur, aside from the release of innumerable substances of unknown toxicity. This process of waste incineration poses a significant threat to public health and the environment. The major impact on health is the higher incidence of cancer and respiratory symptoms; other potential effects are congenital abnormalities, hormonal defects, and increase in sex ratio. The effect on the environmental is in the form of global warming, acidification, photochemical ozone or smog formation, eutrophication, and human and animal toxicity. Thus, there is a need to skip to newer, widely accepted, economical, and environment-friendly technologies. The use of hydroclaves and plasma pyrolysis for the incineration of biomedical wastes leads to lesser environmental degradation, negligible health impacts, safe handling of treated wastes, lesser running and maintenance costs, more effective reduction of microorganisms, and safer disposal.

The onset of antineutrophil cytoplasmic antibody-associated vasculitis immediately after methimazole was switched to propylthiouracil in a woman with Graves' disease who wished to become pregnant

Propylthiouracil (PTU) is recommended as a first-line antithyroid drug (ATD) during first trimester organogenesis in pregnancy because recent evidence suggests that methimazole (MMI) may be associated with congenital anomalies. However, PTU more commonly causes myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, which usually occurs during prolonged treatment, compared with MMI. We report a case of MPO-ANCA-associated vasculitis in a 35-year-old woman with Graves'disease. Although her thyroid function could be maintained euthyroid by MMI, her ATD was switched to PTU because she wished to become pregnant. The patient presented with flu-like symptoms 8 days after starting PTU and developed hemoptysis and dyspnea at 22 days. Her MPO-ANCA titer was 21 ELISA units (EUs) before PTU treatment but increased to 259 EUs at 22 days after PTU treatment. Her clinical condition improved with the discontinuation of PTU and with immunosuppressive therapy. This case indicated that MPO-ANCA vasculitis occurred within several weeks after the initiation of PTU and that this side effect could be caused by the change from MMI to PTU. Thus, our clinical observation suggests that patients treated with PTU should be carefully monitored for MPO-ANCA titers and variable manifestations of MPO-ANCA-associated vasculitis regardless of the period of administration.

Interaction of triphenyltin and an agonist of retinoid X receptor (LGD1069) in embryos of Xenopus tropicalis

Xenopus tropicalis embryos were exposed for 48 h to mixtures of triphenyltin and LGD1069 (an agonist of the retinoid X receptor). The index of fin deficiency (IFD) of the embryos increased in the triphenyltin-treated groups, and the index of axis deficiency (IAD) increased in LGD1069-treated groups in a concentration-dependent manner. When embryos were exposed to mixtures of 5μgSn/L triphenyltin and 1-30 μg/L LGD1069, IFD decreased from 2.9 to 0.6 and IAD increased from 0.1 to 2.4 with increasing LGD1069 concentrations. Conversely, when embryos were exposed to mixtures of 15 μg/L LGD1069 and 1-10 μg Sn/L triphenyltin, IFD increased from 0.1 to 3.0 with increasing triphenyltin concentrations. Co-exposure induced some new phenotypes, such as posteriorized anus. These results suggest that LGD1069 suppressed the teratogenicity of triphenyltin and that the retinoid X receptor was involved in triphenyltin-induced teratogenicity. Histological observations indicate that co-exposure inhibited the invagination of the yolk plug.

The good and the bad of poisonous plants: an introduction to the USDA-ARS Poisonous Plant Research Laboratory

This article provides an overview of the Poisonous Plant Research Laboratory (PPRL), about the unique services and activities of the PPRL and the potential assistance that they can provide to plant poisoning incidences. The PPRL is a federal research laboratory. It is part of the Agricultural Research Service, the in-house research arm of the U.S. Department of Agriculture. The mission of the PPRL is to identify toxic plants and their toxic compounds, determine how the plants poison animals, and develop diagnostic and prognostic procedures for poisoned animals. Furthermore, the PPRL's mission is to identify the conditions under which poisoning occurs and develop management strategies and treatments to reduce losses. Information obtained through research efforts at the PPRL is mostly used by the livestock industry, natural resource managers, veterinarians, chemists, plant and animal scientists, extension personnel, and other state and federal agencies. PPRL currently has 9 scientists and 17 support staff, representing various disciplines consisting of toxicology, reproductive toxicology, veterinary medicine, chemistry, animal science, range science, and plant physiology. This team of scientists provides an interdisciplinary approach to applied and basic research to develop solutions to plant intoxications. While the mission of the PPRL primarily impacts the livestock industry, spinoff benefits such as development of animal models, isolation and characterization of novel compounds, elucidation of biological and molecular mechanisms of action, national and international collaborations, and outreach efforts are significant to biomedical researchers. The staff at the PPRL has extensive knowledge regarding a number of poisonous plants. Although the focus of their knowledge is on plants that affect livestock, oftentimes, these plants are also poisonous to humans, and thus, similar principles could apply for cases of human poisonings. Consequently, the information provided herein could be of benefit to healthcare providers for human cases as well.

Topical corticosteroid use during pregnancy

QUESTION

Some of my pregnant patients have been prescribed various potencies of topical corticosteroids. Do these carry the same fetal risks as systemic corticosteroids?

ANSWER

Pregnant women can be reassured that there is no apparent increased risk of adverse fetal effects when using topical corticosteroids during pregnancy, although some data do suggest fetal growth restriction with more potent topical corticosteroids. Overall, women should be prescribed the lowest potency required whenever possible.

[Analysis and evaluation of the impurity of felodipine and its tablets]

The paper reports the systematic study on felodipine and its impurities in tablets, to improve its quality standards for the control of the related substances. HPLC-DAD, UPLC-MS, IR and NMR methods were used for the isolation of felodipine and its impurities in tablets, their identification and the zebrafish animal model was used for the analysis of the toxic impurities. In felodipine material and its tablets, three impurities are isolated and identified. They are impurity 1 [dimethyl 4-(2, 3-dichlorophenyl)-2, 6-dimethyl-1, 4-dihydropyridine-3, 5-dicarboxylate], impurity 2 [ethyl methyl 4-(2, 3-dichlorophenyl)-2, 6-dimethylpyridine-3, 5-dicarboxylate] and impurity 3 [diethyl 4-(2, 3-dichlorophenyl)-2, 6-dimethyl-1, 4-dihydropyridine-3, 5-dicarboxylate], separately. The result of zebrafish animal model analysis showed that the teratogenic effects of four compounds were: impurity 3 > or = felodipine > impurity 1 > impurity 2, lethal effects were as follows: impurity 2 = impurity 3 > felodipine > or = impurity 1. This study confirmed the toxicity of three impurities in felodipine. According to the results, the paper suggested the amendments to the standard of the medicine and provided the support to the control of impurities in the manufacturing process.

Is carbamazepine safe to take during pregnancy?

QUESTION

Some of my pregnant patients are afraid to take their antiepileptic drugs during pregnancy because of the known risk of malformations and the neurodevelopmental problems associated with valproic acid. Are there similar concerns with carbamazepine?

ANSWER

Similar to valproic acid, carbamazepine increases the risk of neural tube defects; however, it does not increase the risk of other malformations. Carbamazepine is also not associated with an increased risk of developmental delay.

Developmental exposure to valproate and ethanol alters locomotor activity and retino-tectal projection area in zebrafish embryos

Given the minimal developmental neurotoxicity data available for the large number of new and existing chemicals, there is a critical need for alternative methods to identify and prioritize chemicals for further testing. We outline a developmental neurotoxicity screening approach using zebrafish embryos. Embryos were exposed to nominal concentrations of either valproate or ethanol then examined for lethality, malformation, nervous system structure and locomotor activity. Developmental valproate exposure caused locomotor activity changes at concentrations that did not result in malformations and showed a concentration-dependent decrease in retino-tectal projection area in the optic tectum. Developmental ethanol exposure also affected retino-tectal projection area at concentrations below those concentrations causing malformations. As both valproate and ethanol are known human developmental neurotoxicants, these results add to the growing body of evidence showing the potential utility of zebrafish in screening compounds for mammalian developmental neurotoxicity.