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Clemmensen PJ, Brix N, Schullehner J, Ernst A, Harrits Lunddorf LL, Bjerregaard AA, Halldorsson TI, Olsen SF, Hansen B, Stayner LT, Kolstad HA, Sigsgaard T, Ramlau-Hansen CH. Prenatal exposure to nitrosatable drugs and timing of puberty in sons and daughters: A nationwide cohort study. Int J Hyg Environ Health 2023; 254:114271. [PMID: 37820420 DOI: 10.1016/j.ijheh.2023.114271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/12/2023] [Accepted: 10/03/2023] [Indexed: 10/13/2023]
Abstract
BACKGROUND N-nitroso compounds (NOCs) can be formed by endogenous reactions between nitrosatable drugs and nitrite. Animal studies have found that several NOCs are teratogenic, and epidemiological studies report associations between prenatal exposure to nitrosatable drugs and adverse birth outcomes. It is unknown whether prenatal exposure to nitrosatable drugs is harmful to the child's reproductive health, including pubertal development. OBJECTIVES We investigated whether prenatal exposure to nitrosatable drugs was associated with timing of puberty and whether nitrate, nitrite and antioxidant intake modified any association. METHODS The population-based Danish National Birth Cohort (DNBC) Puberty Cohort, which includes 15,819 children, was used to investigate the association between prenatal exposure to nitrosatable drugs and timing of puberty. Around gestational week 11 and gestational week 18, mothers provided information about drug use during pregnancy. The children's self-reported information on onset of pubertal milestones was collected every six months from 11 years of age and throughout puberty. To investigate potential effect modification by nitrite, nitrate and antioxidant intake, information on these factors was obtained from a food frequency questionnaire completed by the mothers in gestational week 25, and information on nitrate concentration in maternal drinking water at her residential address was obtained from monitoring data from public waterworks. Data were analysed using a multivariable regression model for interval-censored data estimating difference in months in timing of puberty between exposure groups. RESULTS A total of 2,715 children were prenatally exposed to nitrosatable drugs. We did not find an association between prenatal exposure to nitrosatable drugs and timing of puberty. This finding was supported by null-findings in the following sub-analyses investigating: 1. subtypes of nitrosatable drugs (secondary and tertiary amines and amides), 2. dose-dependency (duration of drug intake), 3. effect modification by maternal intake of nitrate, nitrite, and antioxidants. 4. confounding by indication. CONCLUSIONS Prenatal exposure to nitrosatable drugs was not associated with timing of puberty. Nitrosatable drugs are commonly used drugs in pregnancy, and further research is needed to allow firm conclusions on the potential effect of prenatal exposure to nitrosatable drugs on the child's reproductive health.
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Affiliation(s)
| | - Nis Brix
- Department of Public Health, Aarhus University, Aarhus, Denmark; Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark
| | - Jörg Schullehner
- Department of Public Health, Aarhus University, Aarhus, Denmark; Danish Big Data Centre for Environment and Health (BERTHA), Aarhus University, Aarhus, Denmark
| | - Andreas Ernst
- Department of Public Health, Aarhus University, Aarhus, Denmark; Department of Urology, Aarhus University Hospital, Aarhus, Denmark
| | | | - Anne Ahrendt Bjerregaard
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark; Center for Clinical Research and Prevention, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark
| | - Thorhallur Ingi Halldorsson
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark; Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland, Iceland
| | - Sjurdur Frodi Olsen
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark; Section of Epidemiology, Institute of Public Health, University of Copenhagen, Denmark
| | | | - Leslie Thomas Stayner
- Division of Epidemiology and Biostatistics, University of Illinois at Chicago, School of Public Health, Chicago, United States
| | - Henrik Albert Kolstad
- Department of Occupational Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Torben Sigsgaard
- Department of Public Health, Aarhus University, Aarhus, Denmark; Danish Big Data Centre for Environment and Health (BERTHA), Aarhus University, Aarhus, Denmark; Cirrau -Centre for Integrated Register-based Research at Aarhus University, Aarhus, Denmark
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Sodium nitrite negatively affects reproductive ability and offspring survival in female mice. Toxicology 2019; 427:152284. [PMID: 31476334 DOI: 10.1016/j.tox.2019.152284] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 08/26/2019] [Accepted: 08/29/2019] [Indexed: 12/12/2022]
Abstract
Sodium nitrite (NaNO2) is an industrial chemical that is frequently used as a food additive to prevent botulism and enhance glossiness, such as curing meat. In addition, in some regions, water source NaNO2 concentrations exceed standard regulatory levels. Whether the excessive intake of NaNO2 has toxic effects on female fertility and fetal development remain unknown. In this study, we administered ICR mice control saline, low-dose NaNO2 (60 mg/kg/day), or high-dose NaNO2 (120 mg/kg/day) by intragastric gavage for 21 days. We then assessed oocyte morphology, spindle-chromosome dynamics, mitochondrial distribution, ATP content, apoptotic cell numbers, DNA damage levels, histone modifications, reactive oxygen species (ROS) levels, and offspring survival. Results showed that NaNO2 treatment decreased oocyte number, impaired polar body extrusion, and increased zona pellucida thickness in oocytes. Furthermore, NaNO2 disrupted MII spindle integrity, caused abnormal mitochondrial distribution, decreased ATP content, and increased levels of ROS and H3K4me2. Moreover, the number of oocytes in early stages of apoptosis and with levels of DNA damage increased in NaNO2-treated mice along with decreased offspring numbers and survival rates. We demonstrated the negative effects of NaNO2 on female reproductive abilities in mice.
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Yang H, Martin B, Schenkel B. On-Demand Generation and Consumption of Diazomethane in Multistep Continuous Flow Systems. Org Process Res Dev 2018. [DOI: 10.1021/acs.oprd.7b00302] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hongwei Yang
- Chemical and Analytical Development, Suzhou Novartis Pharma Technology Company Limited, 18 Tonglian Road, Changshu, Jiangsu 215537, China
| | - Benjamin Martin
- Chemical and Analytical Development, Novartis Pharma AG, Fabrikstrasse, 4002 Basel, Switzerland
| | - Berthold Schenkel
- Chemical and Analytical Development, Novartis Pharma AG, Fabrikstrasse, 4002 Basel, Switzerland
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Vuong AM, Shinde MU, Brender JD, Shipp EM, Huber JC, Sharkey JR, McDonald TJ, Werler MM, Kelley KE, Griesenbeck JS, Langlois PH, Canfield MA. Prenatal Exposure to Nitrosatable Drugs, Dietary Intake of Nitrites, and Preterm Birth. Am J Epidemiol 2016; 183:634-42. [PMID: 26953287 DOI: 10.1093/aje/kwv250] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 09/08/2015] [Indexed: 02/01/2023] Open
Abstract
Prenatal exposure to nitrosatable drugs, including secondary or tertiary amines, has been associated with preterm birth. Associations may be accentuated by higher intakes of dietary nitrites because of the increased formation of N-nitroso compounds. Using data from mothers of babies without major birth defects (controls) from the National Birth Defects Prevention Study, we examined the relationship between nitrosatable drug exposure in conjunction with dietary nitrite intake and preterm birth among 496 mothers of preterm infants and 5,398 mothers with full-term deliveries in 1997-2005. A protective association was observed with a high intake of plant nitrites (adjusted hazard ratio (AHR) = 0.72, 95% confidence interval (CI): 0.53, 0.97). Secondary amines in conjunction with high nitrite intake were associated with preterm birth during the first (AHR = 1.84, 95% CI: 1.14, 2.98), second (AHR = 1.89, 95% CI: 1.17, 3.07), and third (AHR = 2.00, 95% CI: 1.22, 3.29) trimesters. The adjusted hazard ratios for tertiary amine use in the third trimester by increasing tertiles of nitrite intake were 0.67 (95% CI: 0.35, 1.31), 1.25 (95% CI: 0.71, 2.19), and 2.02 (95% CI: 1.17, 3.49). Prenatal exposure to nitrosatable drugs, particularly secondary and tertiary amines, in conjunction with higher levels of dietary nitrite intake may increase the risk of preterm birth.
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Vuong AM, Shinde MU, Brender JD, Shipp EM, Huber JC, Zheng Q, McDonald TJ, Sharkey JR, Hoyt AT, Werler MM, Kelley KE, Langlois PH, Canfield MA. Nitrosatable Drug Exposure during Pregnancy and Preterm and Small-for-Gestational-Age Births. Paediatr Perinat Epidemiol 2015; 29:60-71. [PMID: 25492517 DOI: 10.1111/ppe.12169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Nitrosatable drugs react with nitrite in the stomach to form N-nitroso compounds, observed in animal models to result in adverse pregnancy outcomes, such as birth defects and reduced fetal weight. Previous studies examining prenatal exposure to medications classified as nitrosatable have reported an increased risk of preterm births (PTBs) and small-for-gestational-age (SGA) infants. METHODS Using data from mothers (controls) of babies without major birth defects from the National Birth Defects Prevention Study, prenatal nitrosatable drug usage by trimester and month of gestation was examined in relation to PTBs and SGA infants. RESULTS Positive associations were observed with nitrosatable drug use and PTBs, with the strongest relationship with second trimester exposure (adjusted hazard ratio [aHR] 1.37, [95% confidence interval (CI) 1.10, 1.70]). Of the nitrosatable functional groups, secondary amines were the most notable, with a higher association among women with second (aHR 1.37, [95% CI 1.05, 1.79]) and third (aHR 1.34, [95% CI 1.02, 1.76]) trimester exposure compared with women with no prenatal nitrosatable drug use. Among SGA infants, a borderline association was noted with amide exposure during the third trimester (adjusted odds ratio 1.43 [95% confidence interval [CI] 1.00, 2.05]). CONCLUSIONS Prenatal exposure to nitrosatable drugs during the second and third trimester of pregnancy, particularly secondary amines, might increase the risk of PTBs. However, prenatal exposure to nitrosatable drugs was not associated with SGA infants, with the exception of amide drugs.
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Affiliation(s)
- Ann M Vuong
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH
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Habermeyer M, Roth A, Guth S, Diel P, Engel KH, Epe B, Fürst P, Heinz V, Humpf HU, Joost HG, Knorr D, de Kok T, Kulling S, Lampen A, Marko D, Rechkemmer G, Rietjens I, Stadler RH, Vieths S, Vogel R, Steinberg P, Eisenbrand G. Nitrate and nitrite in the diet: how to assess their benefit and risk for human health. Mol Nutr Food Res 2014; 59:106-28. [PMID: 25164923 DOI: 10.1002/mnfr.201400286] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/29/2014] [Accepted: 08/04/2014] [Indexed: 12/15/2022]
Abstract
Nitrate is a natural constituent of the human diet and an approved food additive. It can be partially converted to nitrogen monoxide, which induces vasodilation and thereby decreases blood pressure. This effect is associated with a reduced risk regarding cardiovascular disease, myocardial infarction, and stroke. Moreover, dietary nitrate has been associated with beneficial effects in patients with gastric ulcer, renal failure, or metabolic syndrome. Recent studies indicate that such beneficial health effects due to dietary nitrate may be achievable at intake levels resulting from the daily consumption of nitrate-rich vegetables. N-nitroso compounds are endogenously formed in humans. However, their relevance for human health has not been adequately explored up to now. Nitrate and nitrite are per se not carcinogenic, but under conditions that result in endogenous nitrosation, it cannot be excluded that ingested nitrate and nitrite may lead to an increased cancer risk and may probably be carcinogenic to humans. In this review, the known beneficial and detrimental health effects related to dietary nitrate/nitrite intake are described and the identified gaps in knowledge as well as the research needs required to perform a reliable benefit/risk assessment in terms of long-term human health consequences due to dietary nitrate/nitrite intake are presented.
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Affiliation(s)
- Michael Habermeyer
- Department of Food Chemistry and Toxicology, University of Kaiserslautern, Kaiserslautern, Germany**
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Brender JD, Weyer PJ, Romitti PA, Mohanty BP, Shinde MU, Vuong AM, Sharkey JR, Dwivedi D, Horel SA, Kantamneni J, Huber JC, Zheng Q, Werler MM, Kelley KE, Griesenbeck JS, Zhan FB, Langlois PH, Suarez L, Canfield MA. Prenatal nitrate intake from drinking water and selected birth defects in offspring of participants in the national birth defects prevention study. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:1083-9. [PMID: 23771435 PMCID: PMC3764078 DOI: 10.1289/ehp.1206249] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 06/11/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND Previous studies of prenatal exposure to drinking-water nitrate and birth defects in offspring have not accounted for water consumption patterns or potential interaction with nitrosatable drugs. OBJECTIVES We examined the relation between prenatal exposure to drinking-water nitrate and selected birth defects, accounting for maternal water consumption patterns and nitrosatable drug exposure. METHODS With data from the National Birth Defects Prevention Study, we linked addresses of 3,300 case mothers and 1,121 control mothers from the Iowa and Texas sites to public water supplies and respective nitrate measurements. We assigned nitrate levels for bottled water from collection of representative samples and standard laboratory testing. Daily nitrate consumption was estimated from self-reported water consumption at home and work. RESULTS With the lowest tertile of nitrate intake around conception as the referent group, mothers of babies with spina bifida were 2.0 times more likely (95% CI: 1.3, 3.2) to ingest ≥ 5 mg nitrate daily from drinking water (vs. < 0.91 mg) than control mothers. During 1 month preconception through the first trimester, mothers of limb deficiency, cleft palate, and cleft lip cases were, respectively, 1.8 (95% CI: 1.1, 3.1), 1.9 (95% CI: 1.2, 3.1), and 1.8 (95% CI: 1.1, 3.1) times more likely than control mothers to ingest ≥ 5.42 mg of nitrate daily (vs. < 1.0 mg). Higher water nitrate intake did not increase associations between prenatal nitrosatable drug use and birth defects. CONCLUSIONS Higher water nitrate intake was associated with several birth defects in offspring, but did not strengthen associations between nitrosatable drugs and birth defects.
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Affiliation(s)
- Jean D Brender
- Department of Epidemiology and Biostatistics, School of Rural Public Health, Texas A&M Health Science Center, College Station, Texas 77843, USA.
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Huber JC, Brender JD, Zheng Q, Sharkey JR, Vuong AM, Shinde MU, Griesenbeck JS, Suarez L, Langlois PH, Canfield MA, Romitti PA, Weyer PJ. Maternal dietary intake of nitrates, nitrites and nitrosamines and selected birth defects in offspring: a case-control study. Nutr J 2013; 12:34. [PMID: 23514444 PMCID: PMC3607976 DOI: 10.1186/1475-2891-12-34] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 03/14/2013] [Indexed: 11/10/2022] Open
Abstract
Background Dietary intake of nitrates, nitrites, and nitrosamines can increase the endogenous formation of N-nitroso compounds in the stomach. Results from animal studies suggest that these compounds might be teratogenic. We examined the relationship between maternal dietary intake of nitrates, nitrites (including plant and animal sources as separate groups), and nitrosamines and several types of birth defects in offspring. Methods For this population-based case–control study, data from a 58-question food frequency questionnaire, adapted from the short Willett Food Frequency Questionnaire and administered as part of the National Birth Defects Prevention Study (NBDPS), were used to estimate daily intake of dietary nitrates, nitrites, and nitrosamines in a sample of 6544 mothers of infants with neural tube defects (NTD)s, oral clefts (OC)s, or limb deficiencies (LD)s and 6807 mothers of unaffected control infants. Total daily intake of these compounds was divided into quartiles based on the control mother distributions. Odds ratios (OR)s and 95% confidence intervals (CI)s were estimated using logistic regression; estimates were adjusted for maternal daily caloric intake, maternal race-ethnicity, education, dietary folate intake, high fat diet (> 30% of calories from fat), and state of residence. Results While some unadjusted ORs for NTDS had 95% (CI)s that excluded the null value, none remained significant after adjustment for covariates, and the effect sizes were small (adjusted odds ratios [aOR] <1.12). Similar results were found for OCs and LDs with the exception of animal nitrites and cleft lip with/without cleft palate (aORs and CIs for quartile 4 compared to quartile 1 =1.24; CI=1.05-1.48), animal nitrites and cleft lip (4th quartile aOR=1.32; CI=1.01-1.72), and total nitrite and intercalary LD (4th quartile aOR=4.70; CI=1.23-17.93). Conclusions Overall, odds of NTDs, OCs or LDs did not appear to be significantly associated with estimated dietary intake of nitrate, nitrite, and nitrosamines.
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Affiliation(s)
- John C Huber
- Department of Epidemiology and Biostatistics, The Texas A&M Health Science Center School of Rural Public Health, MS 1266 TAMU, College Station, TX 77843-1266, USA.
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Diab KAS, Aboul-Ela EI. In vivo Comparative Studies on Antigenotoxicity of Date Palm (Phoenix Dactylifera L.) Pits Extract Against DNA Damage Induced by N-Nitroso-N-methylurea in Mice. Toxicol Int 2012; 19:279-86. [PMID: 23293467 PMCID: PMC3532774 DOI: 10.4103/0971-6580.103669] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aqueous extract of the date palm (Phoenix dactylifera L.) pits was prepared and its antigenotoxic activity was evaluated against N-Nitroso-N-methylurea (NMU) induced mutagenic effect in mice, using chromosome aberration (CA), micronuclei (MN) and DNA fragmentation assays as experimental end points in male mice. Date pits extract (DPE) was given orally to mice at the dose 25 mg/25 g mouse for successive five days in a week up to four consecutive weeks. NMU was used as mutagen and was given intraperitoneal (i.p) injection at single dose 80 mg/kg b.w., 24 hr after last dose of DPE in pre-treatment regimen and 24 hr before the first dose of DPE in the post-treatment regimen. Mice were scarified after one, two and seven days after the end of treatment. The results have shown that pre-and post-treatment regimens of DPE were significantly restored the DNA damage induced by NMU, as revealed by lowering of the occurrence of CAs and MN in bone marrow cells and inhibition of hepatic DNA fragmentation. These findings suggested that DPE produced their inhibitory activity either by desmutagenic or bioantimutagenic manner in pre-and post-treatment regimens respectively.
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Affiliation(s)
- K. A. S. Diab
- Genetics and Cytology Department, National Research Center, Dokki, Cairo, Egypt
| | - E. I. Aboul-Ela
- Genetics and Cytology Department, National Research Center, Dokki, Cairo, Egypt
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Adam MP. The all-or-none phenomenon revisited. ACTA ACUST UNITED AC 2012; 94:664-9. [DOI: 10.1002/bdra.23029] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/14/2012] [Accepted: 04/11/2012] [Indexed: 12/11/2022]
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Brender JD, Werler MM, Kelley KE, Vuong AM, Shinde MU, Zheng Q, Huber JC, Sharkey JR, Griesenbeck JS, Romitti PA, Langlois PH, Suarez L, Canfield MA. Nitrosatable drug exposure during early pregnancy and neural tube defects in offspring: National Birth Defects Prevention Study. Am J Epidemiol 2011; 174:1286-95. [PMID: 22047825 DOI: 10.1093/aje/kwr254] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Nitrosatable drugs, such as secondary or tertiary amines and amides, form N-nitroso compounds in the presence of nitrite. Various N-nitroso compounds have been associated with neural tube defects in animal models. Using data from the National Birth Defects Prevention Study, the authors examined nitrosatable drug exposure 1 month before and 1 month after conception in 1,223 case mothers with neural tube defect-affected pregnancies and 6,807 control mothers who delivered babies without major congenital anomalies from 1997 to 2005. Nitrite intakes were estimated from mothers' responses to a food frequency questionnaire. After adjustment for maternal race/ethnicity, educational level, and folic acid supplementation, case women were more likely than were control women to have taken tertiary amines (odds ratio = 1.60, 95% confidence interval (CI): 1.31, 1.95). This association was strongest with anencephalic births (odds ratio = 1.96, 95% CI: 1.40, 2.73); odds ratios associated with tertiary amines from the lowest tertile of nitrite intake to the highest tertile were 1.16 (95% CI: 0.59, 2.29), 2.19 (95% CI: 1.25, 3.86), and 2.51 (95% CI: 1.45, 4.37), respectively. Odds ratios for anencephaly with nitrosatable drug exposure were reduced among women who also took daily vitamin supplements that contained vitamin C. Prenatal exposure to nitrosatable drugs may increase the risk of neural tube defects, especially in conjunction with a mother's higher dietary intake of nitrites, but vitamin C might modulate this association.
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Affiliation(s)
- Jean D Brender
- School of Rural Public Health, Texas A&M Health Science Center, College Station, USA.
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Komada M, Fujiyama F, Yamada S, Shiota K, Nagao T. Methylnitrosourea induces neural progenitor cell apoptosis and microcephaly in mouse embryos. ACTA ACUST UNITED AC 2010; 89:213-22. [PMID: 20549696 DOI: 10.1002/bdrb.20245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Prenatal exposure to methylnitrosourea (MNU), an alkylating agent, induces microcephaly in mice. However, its pathogenetic mechanism has not been clarified, especially that in the development of the cerebral cortex. METHODS ICR mice were treated with MNU at 10 mg/kg intraperitoneally on day 13.5 or 15.5 of gestation, and the embryos were observed histologically 24 hr after treatment with MNU or at term. To clarify the pathogenesis of microcephaly and histological changes, especially apoptosis, neurogenesis, and neural migration/positioning, we performed histological analysis employing a cell-specific labeling experiment using thymidine-like substances (BrdU, CldU, and IdU) and markers of neurons/neural stem cells. RESULTS Histological abnormalities of the dorsal telencephalon, and the excessive cell death of proliferative neural progenitor/stem cells were noted in the MNU-treated embryos. The highest frequencies of cell death occurred at 36 hr after MNU treatment, and little or no neurogenesis was observed in the ventricular zone of the dorsal telencephalon. Abnormality of the radial migration was caused by the reduction of radial fibers in the radial glias. Birth-date analysis revealed the abnormal positioning of neurons and aberrant lamination of the cerebral cortex. CONCLUSIONS Our data suggest that prenatal exposure to MNU induces the excessive cell death of neural precursor/stem cells, and the defective development of the cerebral cortex, resulting in microcephalic abnormalities.
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Affiliation(s)
- Munekazu Komada
- Congenital Anomaly Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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Griesenbeck JS, Brender JD, Sharkey JR, Steck MD, Huber JC, Rene AA, McDonald TJ, Romitti PA, Canfield MA, Langlois PH, Suarez L. Maternal characteristics associated with the dietary intake of nitrates, nitrites, and nitrosamines in women of child-bearing age: a cross-sectional study. Environ Health 2010; 9:10. [PMID: 20170520 PMCID: PMC2848640 DOI: 10.1186/1476-069x-9-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 02/19/2010] [Indexed: 05/28/2023]
Abstract
BACKGROUND Multiple N-nitroso compounds have been observed in animal studies to be both mutagenic and teratogenic. Human exposure to N-nitroso compounds and their precursors, nitrates and nitrites, can occur through exogenous sources, such as diet, drinking water, occupation, or environmental exposures, and through endogenous exposures resulting from the formation of N-nitroso compounds in the body. Very little information is available on intake of nitrates, nitrites, and nitrosamines and factors related to increased consumption of these compounds. METHODS Using survey and dietary intake information from control women (with deliveries of live births without major congenital malformations during 1997-2004) who participated in the National Birth Defects Prevention Study (NBDPS), we examined the relation between various maternal characteristics and intake of nitrates, nitrites, and nitrosamines from dietary sources. Estimated intake of these compounds was obtained from the Willet Food Frequency Questionnaire as adapted for the NBDPS. Multinomial logistic regression models were used to estimate odds ratios and 95% confidence intervals for the consumption of these compounds by self-reported race/ethnicity and other maternal characteristics. RESULTS Median intake per day for nitrates, nitrites, total nitrites (nitrites + 5% nitrates), and nitrosamines was estimated at 40.48 mg, 1.53 mg, 3.69 mg, and 0.472 microg respectively. With the lowest quartile of intake as the referent category and controlling for daily caloric intake, factors predicting intake of these compounds included maternal race/ethnicity, education, body mass index, household income, area of residence, folate intake, and percent of daily calories from dietary fat. Non-Hispanic White participants were less likely to consume nitrates, nitrites, and total nitrites per day, but more likely to consume dietary nitrosamines than other participants that participated in the NBDPS. Primary food sources of these compounds also varied by maternal race/ethnicity. CONCLUSIONS Results of this study indicate that intake of nitrates, nitrites, and nitrosamines vary considerably by race/ethnicity, education, body mass index, and other characteristics. Further research is needed regarding how consumption of foods high in nitrosamines and N-nitroso precursors might relate to risk of adverse pregnancy outcomes and chronic diseases.
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Affiliation(s)
- John S Griesenbeck
- Department of Epidemiology and Biostatistics, School of Rural Public Health, Texas A&M Health Science Center, College Station, TX, 77843-1266, USA
| | - Jean D Brender
- Department of Epidemiology and Biostatistics, School of Rural Public Health, Texas A&M Health Science Center, College Station, TX, 77843-1266, USA
| | - Joseph R Sharkey
- Department of Social and Behavioral Health, School of Rural Public Health, Texas A&M Health Science Center, College Station, TX, 77843-1266, USA
| | - Michelle D Steck
- Department of Epidemiology and Biostatistics, School of Rural Public Health, Texas A&M Health Science Center, College Station, TX, 77843-1266, USA
| | - John C Huber
- Department of Epidemiology and Biostatistics, School of Rural Public Health, Texas A&M Health Science Center, College Station, TX, 77843-1266, USA
| | - Antonio A Rene
- Department of Epidemiology and Biostatistics, School of Rural Public Health, Texas A&M Health Science Center, College Station, TX, 77843-1266, USA
| | - Thomas J McDonald
- Department of Environmental and Occupational Health, School of Rural Public Health, Texas A&M Health Science Center, College Station, TX, 77843-1266, USA
| | - Paul A Romitti
- Department of Epidemiology, 200 Hawkins Dr, University of Iowa, Iowa City, IA, 52242, USA
| | - Mark A Canfield
- Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, PO Box 149347, MC 1964, Austin, TX, 78714-9347, USA
| | - Peter H Langlois
- Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, PO Box 149347, MC 1964, Austin, TX, 78714-9347, USA
| | - Lucina Suarez
- Environmental Epidemiology and Disease Registries Section, Texas Department of State Health Services, 1100 W. 49th St, Austin, TX, 78756, USA
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14
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Modulation of Carbohydrate Metabolism During N-Methyl N-Nitrosourea Induced Neurotoxicity in Mice: Role of Curcumin. Neurochem Res 2010; 35:660-5. [DOI: 10.1007/s11064-009-0117-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2009] [Indexed: 11/27/2022]
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15
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Padmanabhan R, Abdulrazzaq YM, Bastaki SMA, Shafiullah MM. Intrauterine growth restriction and skeletal variations in mouse fetuses induced by vigabatrin administered at preimplantation stages of development. Congenit Anom (Kyoto) 2008; 48:29-39. [PMID: 18230119 DOI: 10.1111/j.1741-4520.2007.00177.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Epileptic women do not withdraw antiepileptic drug (AED) therapy during pregnancy, therefore, exposure to AED during preimplantation stages might result in considerable embryonic concentrations endangering development. Neither clinical nor experimental research has addressed this important issue adequately. Vigabatrin (VGB), a second generation AED, is both effective and well tolerated as an add-on therapy in epilepsy with partial seizures. However, there is little data on the possible reproductive toxicity of this widely used drug. The objective of the present study was to evaluate the effects of VGB on pregnancy and pregnancy outcome in an experimental model. VGB was administered in single doses of 450 mg/kg intraperitoneally (i.p.) to groups of mice on one of gestation days (GD) 1, 3, or 5. The treated animals consumed moderately reduced amounts of food and water on the day of treatment, so the controls were saline-injected and food and water-restricted to match the amounts consumed by the experimental animals. All animals were killed on GD 18. VGB treatment did not interfere with implantation, nor did it cause significant embryo resorption. However, it caused significant reduction in fetal bodyweight and increased frequency of growth restricted fetuses which weighed two standard deviations (SD) less than the mean of the controls. The VGB group fetuses also had retarded development of the skeletal system in terms of delay in maturity of the suproccipital bone development, cervical and coccygeal vertebral hypoplasia, and poor ossification of the bones of the fore and hind paws. Another major finding was the increased incidence of minor malformations, such as the presence of cervical ribs and sternal anomalies. The results of this study show that VGB administered at preimplantation stages of development causes intrauterine growth restriction (IUGR) and augments minor malformation rates in mice. Future studies must address the mechanisms of VGB-induced IUGR and minor malformations.
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Affiliation(s)
- Rengasamy Padmanabhan
- Department of Anatomy, Faculty of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates.
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16
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Yokoi R, Suda S, Kobayashi K, Kuroda J, Kusama H, Kagami H, Ono T. Differential susceptibility of rat embryos to methyl methanesulfonate during the pregastrulation period. J Toxicol Sci 2008; 32:495-503. [PMID: 18198481 DOI: 10.2131/jts.32.495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The effects of exposure of pregnant rats to methyl methanesulfonate (MMS), an alkylating agent, during the pregastrulation period on embryonic and placental development were investigated. SD rats were treated orally with a single dose of MMS (200 mg/kg) in the morning of gestation days 0, 1, 2, 3, 4, 5, or 6 (GD0 to GD6 groups, respectively). The uterine contents including fetuses and placentas of the dams were examined on gestation day 20. The individual fetuses and placentas were weighed, and the fetuses were examined for external, visceral and skeletal anomalies. The progress of ossification was also evaluated. Both pre- and postimplantation embryonic mortalities were higher in the GD0 group than in the control group. The postimplantation loss was also increased for the GD3, GD4 and GD6 groups. Fetal malformations were rare in survivors of all the MMS-treated groups. Intrauterine growth retardation was apparent for fetuses in groups GD5 and GD6. In addition, placental weight was reduced in the GD6 group, but it was increased in the GD0 group. Effects of MMS on embryonic mortality or on fetal or placental growth were absent or minimal in the GD1 and GD2 groups. These results suggest that the susceptibility of rat embryos to MMS varies during the pregastrulation period.
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Affiliation(s)
- Ryohei Yokoi
- Interdisciplinary Graduate School of Science and Technology, Shinshu University, Nagano, Japan.
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17
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Yokoi R, Hayashi M, Tamura T, Kobayashi K, Kuroda J, Kusama H, Kagami H, Ono T. Embryonic mortality and intrauterine growth retardation (IUGR) associated with placental alterations in pregnant rats treated with methyl methanesulfonate (MMS) at the peri-implantation stage. J Toxicol Sci 2008; 33:585-98. [DOI: 10.2131/jts.33.585] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Ryohei Yokoi
- Interdisciplinary Graduate School of Science and Technology, Shinshu University
- Toxicology Research Laboratory, Kissei Pharmaceutical Co., Ltd
| | | | - Toru Tamura
- Toxicology Research Laboratory, Kissei Pharmaceutical Co., Ltd
| | - Kazuo Kobayashi
- Toxicology Research Laboratory, Kissei Pharmaceutical Co., Ltd
| | - Junji Kuroda
- Toxicology Research Laboratory, Kissei Pharmaceutical Co., Ltd
| | - Hiroshi Kusama
- Toxicology Research Laboratory, Kissei Pharmaceutical Co., Ltd
| | | | - Tamao Ono
- Faculty of Agriculture, Shinshu University
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18
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Prater MR, Zimmerman KL, Ward DL, Holladay SD. Reduced birth defects caused by maternal immune stimulation in methylnitrosourea-exposed mice: association with placental improvement. ACTA ACUST UNITED AC 2005; 70:862-9. [PMID: 15526292 DOI: 10.1002/bdra.20082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Methylnitrosourea (MNU) is a potent carcinogen and teratogen that is associated with central nervous system, craniofacial, skeletal, ocular, and appendicular birth defects following transplacental exposure at critical time points during development, and preliminary studies have suggested that nonspecific maternal immunostimulation may offer protection against development of these birth defects. METHODS Our study examined morphologic alterations in fetal limb and digital development and placental integrity following maternal exposure to MNU on GD 9 in CD-1 mice, and characterized the improvement in placental integrity and abrogation of fetal defects following maternal immune stimulation with interferon-gamma (IFN-gamma) on GD 7. RESULTS Fetal limbs were significantly shortened (p < 0.0001) and incidence of limb and digital defects (syndactyly, polydactyly, oligodactyly, clubbing, and webbing) was dramatically increased following mid-gestational maternal MNU exposure. Maternal immune stimulation with IFN-gamma on GD 7 lessened incidence of fetal limb shortening and maldevelopment on GD 12 and 14. Further, disruption of placental spongiotrophoblast integrity, increased cell death in placental trophoblasts with increased intercellular spaces in the spongiotrophoblast layer and minimal inflammation, and increased loss of fetal labyrinthine endothelial cells from MNU-exposed dams suggested that MNU-induced placental breakdown may contribute to fetal limb and digital maldevelopment. MNU + IFN-gamma was associated with diminished cell death within all layers of the placenta, especially in the labyrinthine layer. CONCLUSIONS These data verify improved distal limb development in MNU-exposed mice as a result of maternal IFN-gamma administration, and suggest a link between placental integrity and proper fetal development.
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MESH Headings
- Abnormalities, Drug-Induced/embryology
- Abnormalities, Drug-Induced/etiology
- Abnormalities, Drug-Induced/immunology
- Abnormalities, Drug-Induced/prevention & control
- Alkylating Agents/toxicity
- Animals
- Drug Therapy, Combination
- Ear, Inner/drug effects
- Ear, Inner/immunology
- Ear, Inner/pathology
- Endothelial Cells/drug effects
- Endothelial Cells/immunology
- Endothelial Cells/pathology
- Female
- Immune System/drug effects
- Interferon-gamma/pharmacology
- Limb Deformities, Congenital/chemically induced
- Limb Deformities, Congenital/immunology
- Limb Deformities, Congenital/prevention & control
- Male
- Maternal-Fetal Exchange
- Methylnitrosourea/toxicity
- Mice
- Placenta/immunology
- Pregnancy
- Trophoblasts/drug effects
- Trophoblasts/immunology
- Trophoblasts/pathology
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Affiliation(s)
- Mary Renee Prater
- Edward Via Virginia College of Osteopathic Medicine, Blacksburg, Virginia 24061, USA.
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19
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Allen AS, Barnhart HX. Joint models for toxicology studies with dose-dependent number of implantations. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2002; 22:1165-1173. [PMID: 12530786 DOI: 10.1111/1539-6924.00280] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Many chemicals interfere with the natural reproductive processes in mammals. The chemicals may prevent the fertilization of an egg or keep a zygote from implanting in the uterine wall. For this reason, toxicology studies with pre-implantation exposure often exhibit a dose-related trend in the number of observed implantations per litter. Standard methods for analyzing developmental toxicology studies are conditioned on the number of implantations in the litter and therefore cannot estimate this effect of the chemical on the reproductive process. This article presents a joint modeling approach to estimating risk in toxicology studies with pre-implantation exposure. In the joint modeling approach, both the number of implanted fetuses and the outcome of each implanted fetus is modeled. Using this approach we show how to estimate the overall risk of a chemical that incorporates the risk of lost implantation due to pre-implantation exposure. Our approach has several distinct advantages over previous methods: (1) it is based on fitting a model for the observed data and, therefore, diagnostics of model fit and selection apply; (2) all assumptions are explicitly stated; and (3) it can be fit using standard software packages We illustrate our approach by analyzing a dominant lethal assay data set (Luning et al., 1966, Mutation Research, 3, 444-451) and compare ourresults with those of Rai and Van Ryzin (1985, Biometrics, 41,1-9) and Dunson (1998, Biometrics, 54, 558-569). In a simulation study, our approach has smaller bias and variance than the multiple imputation procedure of Dunson.
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Affiliation(s)
- Andrew S Allen
- Department of Biostatistics and Bioinformatics and Duke Clinical Research Institute, Duke University Medical Center, Durham, NC 27715, USA.
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20
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Nagao T, Saitoh Y, Yoshimura S. Possible mechanism of congenital malformations induced by exposure of mouse preimplantation embryos to mitomycin C. TERATOLOGY 2000; 61:248-61. [PMID: 10716743 DOI: 10.1002/(sici)1096-9926(200004)61:4<248::aid-tera3>3.0.co;2-c] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ICR mice were treated intraperitoneally with mitomycin C at 5 mg/kg on day 3 of gestation. On day 18 of gestation, fetuses of treated dams were inspected for external, skeletal and visceral malformations. At 6 or 12 hr after mitomycin C treatment, the blastocysts were obtained from the uteri of treated dams and the degenerated cells within inner cell mass (ICM) and trophectoderm (TE) tissues were examined microscopically. On day 5, 8, 11, or 18 of gestation, the uteri of treated dams were obtained and those including embryos/fetuses and placentae were examined histologically. Finally, on each of gestational days 5-14, the blood of the treated dams was collected and the hematological parameters determined. Pre- and postimplantation losses in the dams treated with mitomycin C were significantly increased; increased frequency of abdominal wall defects and lumbar ribs in term fetuses, decreased fetal weight, and increased placental weight were noted as well. No significant increase in visceral malformations was found in term fetuses treated with mitomycin C. Frequency of degenerated cells within ICM and TE of blastocysts from dams treated with mitomycin C was significantly increased as compared with the controls. In dams treated with mitomycin C, decidua developed insufficiently and the trophoblast giant cell layer was not separated from the uterine lumen by maternal components; hemorrhage from the denuded trophoblast giant cell layer into the uterine lumen was noted. The number of erythrocytes, as well as hemoglobin concentration, hematocrit, and the percentage of reticulocytes in blood of dams treated with mitomycin C were significantly lower from days 6-12 of gestation, as compared with controls. The results of the present study showed that an increase in number of degenerated cells within blastocysts results in preimplantation loss and both maternal and embryonic hypoxia during major organogenesis results in postimplantation loss and congenital fetal malformations.
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Affiliation(s)
- T Nagao
- Department of Developmental Toxicology, Hatano Research Institute, Food and Drug Safety Center, Kanagawa 257-8523, Japan.
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21
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Abstract
Both a conceptual and a practical borderland between teratology and mutagenesis is early embryogenesis, the period between fertilization and gastrulation. Radiation and a variety of chemicals adversely affect the early conceptus leading to in utero mortality and malformations. The post-fertilization period of susceptibility differs from exposures of gametes, the later producing excessive pre- and peri-implantational death and low rates of fetal anomalies predominated by growth retardation. In contrast mutagen exposure of the zygote induces peri-implantational death, pan-gestational death and fetal anomalies predominated by hydrops, abdominal wall defects, and eye aberrations. The mechanism for this pathology remains unclear. These same agents produce a broader range of phenotypic anomalies during the remainder of pre-gastrulation development with anomalies overlapping those induced during organogenesis. Retinoic acid and 5-azacytidine administered prior to gastrulation produce novel malformation syndromes indicative of gene expression modification. The rates and types of defects from mutagen treatment of both gametes and the early conceptus contrast with those resulting from embryonic treatment during organogenesis, and the mechanisms are likely to differ. The pre-gastrulation period has not been explored to the extent reported during gametogenesis or organogenesis. Pre-gastrulation teratology is a new area of investigation with relevance both to reproductive toxicology and to mammalian developmental biology.
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Affiliation(s)
- J C Rutledge
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, USA.
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22
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Czeizel AE, Mosonyi A. Monitoring of early human fetal development in women exposed to large doses of chemicals. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1997; 30:240-244. [PMID: 9329649 DOI: 10.1002/(sici)1098-2280(1997)30:2<240::aid-em17>3.0.co;2-d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The toxicological in-patient hospital in Budapest is responsible for the care of chemically poisoned persons from a population of 3 million. A population-based prospective epidemiological study of all pregnant women admitted from 1985 to 1993 was used to evaluate effects of large doses of chemicals on human fetal development. Of 559 self-poisoned pregnant women identified, two died from the poisoning. A total of 213 fetuses were in the first month of their postconception development. Of these, 126 had evaluated pregnancy outcomes: 111 ended in very early loss, 3 ended in clinical miscarriage, and 12 survived to delivery. (In addition 73 pregnancies were terminated and one pregnant woman died.) The 12 liveborn infants had two congenital abnormalities that were probably not related to their mother's self-poisoning. Though based on small numbers, these findings are consistent with an "all-or-nothing" effect of chemical poisoning very early in human gestation.
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Affiliation(s)
- A E Czeizel
- Department of Human Genetics and Teratology, National Institute of Public Health-WHO Collaborating Centre for the Community Control of Hereditary Diseases, Budapest, Hungary
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23
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Jacquet P, de Saint-Georges L, Vankerkom J, Baugnet-Mahieu L. Embryonic death, dwarfism and fetal malformations after irradiation of embryos at the zygote stage: studies on two mouse strains. Mutat Res 1995; 332:73-87. [PMID: 7500994 DOI: 10.1016/0027-5107(95)00156-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Female mice of the BALB/c and CF1 strains were mated and irradiated with various doses of X-rays 7 h after presumed fertilization. 18 days later, females were killed and their uteri examined for prenatal mortality at the different stages of development. Living fetuses were weighed and examined for the presence of external malformations. A number of them were also examined for skeletal anomalies. Radiation induced mainly a dose-dependent increase of the preimplantation loss in the BALB/c strain and of the early postimplantation loss in the CF1 strain. Embryos of the BALB/c strain were refractory to the induction of teratogenic effects after such preimplantation irradiation. In CF1 mice, the frequency of malformed fetuses increased regularly after irradiation, the difference with controls being significant for the doses of 10, 50 and 100 cGy. Dwarfism occurrence also appeared to be increased by irradiation in this strain, although the importance of this effect varied depending on the criterion chosen for the assessment of dwarfs. With the definition proposed in the present paper, the increase in the frequency of dwarfs paralleled that of malformed fetuses, being significant after doses of 50 and 100 cGy. Irradiation did not increase the frequency of skeletal anomalies. A careful examination of the various data obtained to data led us to conclude that radiation may possibly be teratogenic in several mouse strains, when administered as early as during the one-cell stage and, to a lesser extent, during the following preimplantation stages. However, early prenatal mortality will remain by far the greatest risk associated with an exposure to radiation during this period. Moreover, the relativity of the risk of abnormality due to such irradiation should be considered in the context of the high prevalence of developmental defects spontaneously occurring during human pregnancy.
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Affiliation(s)
- P Jacquet
- Department of Radioprotection, CEN/SCK, Mol, Belgium
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24
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Abstract
Experimental studies indicated that the mouse zygote is susceptible to experimental induction of developmental anomalies including defects (mainly hydrops), growth retardation and mid- and late-gestational death with certain mutagenic agents. The material of the Hungarian Optimal Family Planning Program is appropriate to check this finding in a human material because participants were asked to visit the coworkers of the Program immediately after the first missed menstrual period and data concerning potentially hazardous environmental factors were obtained. At that time participants were immediately after the pre- and implantation period and they had no knowledge about their pregnancy outcomes. In 1994 the data of their pregnancy outcomes are available. Of 5453 evaluated pregnancies, 1167 were selected for this study because they visited the coworkers of the Program within 28 days post conception. Of 1167 pregnancies, 316 (27%) were exposed to some environmental factors, mainly drugs. A mild intrauterine growth retardation was found in the exposed group. The rate of congenital abnormalities and infant death did not differ between the exposed and unexposed groups. The detailed analysis of different congenital abnormality groups also did not show any significant difference between the exposed and unexposed groups. These negative results are explained by the fact that the observed environmental factors are not mutagenic, at least not in the dosage which was used, or the human zygote is not sensitive to mutagenic agents in the post-conceptional days.
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Affiliation(s)
- C Siffel
- Department of Human Genetics and Teratology, National Institute of Hygiene, WHO Collaborating Centre for the Community Control of Hereditary Diseases OKI, Budapest, Hungary
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25
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Rutledge JC, Generoso WM, Shourbaji A, Cain KT, Gans M, Oliva J. Developmental anomalies derived from exposure of zygotes and first-cleavage embryos to mutagens. Mutat Res 1992; 296:167-77. [PMID: 1279403 DOI: 10.1016/0165-1110(92)90040-g] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Results of continuing studies indicate that the mouse zygote and two-cell embryo stages are a window of susceptibility in the experimental induction of congenital anomalies with certain mutagenic agents. The mechanisms by which the mutagens initiate the pathogenesis of these developmental defects are not known. However, in certain cases there is evidence that a nonconventional, perhaps epigenetic, mechanism is involved. Detailed characterization of the spectrum of anomalies induced and comparison of responses at the various stages exposed allowed classification of the mutagens generally into two groups. One group is characterized by being effective only in the early stages of zygote development and capable of producing a relatively high incidence of fetal death and hydrops. The other group affects all of the zygote stages studied as well as the two cell-embryo, but does not increase the incidence of fetal death and hydrops. Except for hydrops, chemicals in the two groups do not differ in terms of the types of anomalies present among malformed live fetuses, which bear a resemblance to a subset of common, sporadic human developmental anomalies that are of unknown etiology. This similarity raises the possibility that certain human developmental defects may have their origins in events that happen in the zygote and early pre-implantation stages.
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Affiliation(s)
- J C Rutledge
- Department of Laboratory Medicine, Children's Hospital and Medical Center, Seattle, WA 98105
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