The dimethadione-exposed rat fetus: an animal model for the prenatal ultrasound characterization of ventricular septal defect.

BACKGROUND: Ventricular septal defect (VSD) is the most prevalent congenital heart disease (CHD) and is easily misdiagnosed or missed. An appropriate VSD animal model could be used to analyze the ultrasound characteristics and their related pathological bases, and provides the opportunity to further explore the pathogenesis of VSD. Currently, little is known about whether ultrahigh-frequency ultrasound biomicroscopy (UBM) is suitable to diagnose VSD of fetal rats. There is no research on whether a dimethadione (DMO)-induced fetal VSD model is suitable for the observation and analysis of imaging characteristics and the associated pathological basis. METHODS: We used DMO to induce VSD. UBM was used to perform the prenatal ultrasound characterization. With the pathological results used as the gold standard, the ultrasound characteristics and their related pathological bases were analyzed. RESULTS: The incidence of VSD in the DMO group was 42.05% and 39.71% (diagnosed by UBM and pathology, respectively, P > 0.05). The prenatal ultrasound findings and pathological basis of various diseases, including isolated VSD, complex CHD containing VSD, and extracardiac lesions, were detected and discussed. It was discovered that some fetuses showed features of noncompacted ventricular myocardium, and for the first time, clusters of red blood cell traversing the cardiomyocytes. CONCLUSIONS: The DMO-induced VSD model is a low-cost model with a high success rate and is suitable for the observation and analysis of VSD. UBM is suitable for evaluating VSD.

Associations of trace elements in blood with the risk of isolated ventricular septum defects and abnormal cardiac structure in children.

This study sought to determine correlations between the presence of isolated ventricular septum defects (VSDs) and blood levels of trace elements. A total of 144 patients with VSDs and 144 controls were recruited for cross-sectional assessment of trace elements and examination of cardiac structures in the Jiangsu and Anhui provinces between 2016 and 2018. Logistic regression was performed to explore the relationships between VSDs and trace elements. Additionally, general linear regression models were used to investigate relationships between trace elements and echocardiography indicators. Relative to the lowest zinc (Zn) concentrations, the highest Zn concentrations may be associated with lower odds of VSD development (OR = 0.03, 95% confidence interval [CI] = 0.01-0.29, P < 0.001). However, no significant relationships between the concentrations of other trace elements and the risk of VSD were identified. Aorta (AO) diameters were markedly smaller in the VSD group, whereas no significant between-group differences were observed for other echocardiography indicators. After adjusting for age and gender, linear regression indicated a significant association between Zn level and mean AO diameter (beta coefficient = 0.247, 95% CI = 0.126-0.367). Zn deficiency was observed in patients with isolated VSDs. Further work to explore the mechanisms by which Zn deficiency leads to VSDs is warranted.

Statin exposure during first trimester of pregnancy is associated with fetal ventricular septal defect.

BACKGROUND: A growing number of young women are exposed to statins during their first trimester of pregnancy. The goal of this study is to examine if first trimester statin exposure is associated with an increase in risk of fetal congenital cardiac anomalies. METHODS: In a cohort of 379,238 pregnancies, we examined the risk of fetal congenital cardiac anomalies in association with maternal exposure to statin therapy during the first trimester of pregnancy using logistic regression models and propensity score matching methods. RESULTS: 280 women were exposed to statins. Congenital cardiac anomalies were present in 14 (5.0%) of pregnancies exposed to statin and 5282 (1.4%) of non-exposed pregnancies. First-trimester statin exposure was associated with an increased risk of ventricular septal defect (adjusted odds ratio [OR] 3.3, 95% confidence interval [CI]l 1.8-6.0, p < 0.001). This association was confirmed in an analysis using a propensity score-matched cohort (OR 4.7, 95% CI 2.0-10.8, p < 0.001). CONCLUSIONS: Exposure to statins during the first trimester of pregnancy is associated with fetal ventricular septal defect.

Maternal exposure to air pollutant PM2.5 and PM10 during pregnancy and risk of congenital heart defects.

Maternal exposure to ambient air pollution has increasingly been linked to congenital heart defects (CHDs). The objective of this study was to evaluate whether high levels of maternal exposure to PM2.5 and PM10 are related to increased risk of CHDs in Wuhan, China. We conducted a cohort study with a total of 105,988 live-born infants, stillbirths, and fetal deaths. The study included mothers living in the urban district of Wuhan during pregnancy over the 2-year period from 10 June 2011 to 9 June 2013. For each study participant, we assigned 1-month and 1-week averages of PM10 and PM2.5 exposure based on measurements obtained from the nearest exposure monitor to the living residence of mothers during their early pregnancy period. Logistic regression analyses were conducted to calculate the adjusted odds ratios (aORs) and 95% confidence intervals (CI) for the association between exposure to these ambient air pollutants during early pregnancy and CHDs. We observed an increased risk of CHDs, particularly ventricular septal defect (VSD), with increasing PM2.5 exposure. Using 1-week averages, we also observed significant monotonically increasing associations between PM2.5 exposure during weeks 7-10 of pregnancy and risk of VSD, with aORs ranging from 1.11 to 1.17 (95% CI: 1.02-1.20, 1.03-1.22, 1.05-1.24, and 1.08-1.26 separately) per a 10 µg/m(3) change in PM2.5 concentration. Our study contributes to the small body of knowledge regarding the association between in utero exposure to air pollution and CHDs, but confirmation of these associations will be needed in future studies.

Coexistence of Fetal Cardiac Malformation and Maternal Drug-Induced Lupus: Is Lamotrigine Safe?

Lamotrigine (LTG) is a widely used second-generation antiepileptic drug for long-term therapy of epileptic patients. Although LTG monotherapy during pregnancy is assumed to be relatively safe, teratogenic effects related to LTG has been reported previously. The presence of fetal malformations and maternal drug-induced lupus erythematosus concurrently in a pregnant women using LTG have not been reported before. We herein report a term infant with coarctation of aorta and ventricular septal defect, who was born to a mother treated with LTG for epilepsy before conception and throughout pregnancy. The mother was diagnosed with drug-induced lupus erythematosus at the 36th gestational week, and the symptoms resolved after discontinuation of the drug. Fetal cardiac anomalies should be searched in mothers who were exposed to LTG during pregnancy.

Selective serotonin reuptake inhibitor antidepressant use in first trimester pregnancy and risk of specific congenital anomalies: a European register-based study.

Evidence of an association between early pregnancy exposure to selective serotonin reuptake inhibitors (SSRI) and congenital heart defects (CHD) has contributed to recommendations to weigh benefits and risks carefully. The objective of this study was to determine the specificity of association between first trimester exposure to SSRIs and specific CHD and other congenital anomalies (CA) associated with SSRI exposure in the literature (signals). A population-based case-malformed control study was conducted in 12 EUROCAT CA registries covering 2.1 million births 1995-2009 including livebirths, fetal deaths from 20 weeks gestation and terminations of pregnancy for fetal anomaly. Babies/fetuses with specific CHD (n = 12,876) and non-CHD signal CA (n = 13,024), were compared with malformed controls whose diagnosed CA have not been associated with SSRI in the literature (n = 17,083). SSRI exposure in first trimester pregnancy was associated with CHD overall (OR adjusted for registry 1.41, 95% CI 1.07-1.86, fluoxetine adjOR 1.43 95% CI 0.85-2.40, paroxetine adjOR 1.53, 95% CI 0.91-2.58) and with severe CHD (adjOR 1.56, 95% CI 1.02-2.39), particularly Tetralogy of Fallot (adjOR 3.16, 95% CI 1.52-6.58) and Ebstein's anomaly (adjOR 8.23, 95% CI 2.92-23.16). Significant associations with SSRI exposure were also found for ano-rectal atresia/stenosis (adjOR 2.46, 95% CI 1.06-5.68), gastroschisis (adjOR 2.42, 95% CI 1.10-5.29), renal dysplasia (adjOR 3.01, 95% CI 1.61-5.61), and clubfoot (adjOR 2.41, 95% CI 1.59-3.65). These data support a teratogenic effect of SSRIs specific to certain anomalies, but cannot exclude confounding by indication or associated factors.

Investigation of the teratogenic potential of VLA-4 antagonist derivatives in rats.

Very late antigen-4 (VLA-4), which is concerned with cell-cell adhesion, plays important roles in development of the heart, and some VLA-4 antagonists cause cardiac anomalies. In this study, we evaluated the teratogenic potential of VLA-4 antagonist derivatives as screening, and investigated the conditions that induce cardiac anomalies. Seventeen compounds were orally administered to pregnant rats throughout the organogenesis period, and fetal examinations were performed. In addition, drug concentrations in the embryos were assayed. As a result, the incidence of ventricular septal defect (VSD) ranged from 0 to 100% depending on the compound. Plasma drug concentrations in the dams were related to increased incidence of VSD; however, these incidences were not increased when the concentration of the compound in the embryos at 24h after dosing was low. It is considered that continuous pharmacological activity in the embryo for more than 24h might disrupt closure of the ventricular septum.

Maternal use of cyclobenzaprine (Flexeril) may induce ductal closure and persistent pulmonary hypertension in neonates.

A full-term male infant presented shortly after birth with respiratory distress. An echocardiogram done within the first hour of life showed an elevated pulmonary artery pressure, an associated right ventricular hypertrophy without a patent ductus arteriosus. The patient was treated for persistent pulmonary hypertension with favorable response. Maternal history was unremarkable except for chronic low back pain treated with cyclobenzaprine (Flexeril®). A proposed mechanism for cyclobenzaprine includes inhibition of norepinephrine and serotonin reuptake, factors known to inhibit prostaglandin and nitric oxide. These two factors are the leading causes of in-utero ductal closure. This report is the first to indicate that cyclobenzaprine use during late pregnancy should be considered a potential cause of early ductal closure.

Síndrome de Moebius, comunicación interventricular asociado a exposición prenatal a misoprostol / Moebius Syndrome, ventricular septal defect due to prenatal exposure to misoprostol

Introducción: El síndrome o secuencia de Moebius se caracteriza por la afectación del nervio facial y nervio abducens y puede estar asociado a defectos congênitos orofaciales y de las extremidades. Adicionalmente en las dos últimas décadas se han reortada una posible asociación con exposición prenatal a misoprostol. Objetivo: Presentar un caso de síndrome de Moebius con cardiopatía compleja (comunicación interventricular y pseudocoartación de aorta) asociado a exposición prenatal a misoprostol. Caso clínico: Paciente de 5 años quien consulta por antecedente de retardo en el desarrollo psicomotor, anomalías craneofaciales, cardiacas y de las extremidades, con antecedente de exposición prenatal a misoprostol, a quien se le diagnóstica síndrome de Moebius. Conclusiones: Aunque la etiología de este síndrome no es clara, un mecanismo fisiopatológico involucrado es el de la hipoxia que puede ser secundario a la exposición prenatal a misoprostol.

Introduction: Moebius syndrome/sequence is characterized by facial and abducens nerve damage and may be associated with congenital orofacial and limb defects. Additionally, in the last two decades, a possible association with prenatal exposure to misoprostol has been reported. Objective: To present a case of Moebius Syndrome with complex heart disease (ventricular septal defect and pseudocoarctation of the aorta) associated with prenatal exposure to misoprostol. Case report: A 5 year old patient diagnosed with Moebius Syndrome who consulted specialists due to psychomotor retardation, craniofacial, heart and limb defects, and with a history of prenatal exposure to misoprostol is presented. Conclusions: Although the etiology of this syndrome is not clear, hypoxia is a pathophysiological mechanism involved, which can be secondary to prenatal exposure to misoprostol.

Moderately high intake of folic acid has a negative impact on mouse embryonic development.

BACKGROUND: The incidence of neural tube defects has diminished considerably since the implementation of food fortification with folic acid (FA). However, the impact of excess FA intake, particularly during pregnancy, requires investigation. In a recent study, we reported that a diet supplemented with 20-fold higher FA than the recommended intake for rodents had adverse effects on embryonic mouse development at embryonic days (E)10.5 and 14.5. In this report, we examined developmental outcomes in E14.5 embryos after administering a diet supplemented with 10-fold higher FA than recommended to pregnant mice with and without a mild deficiency of methylenetetrahydrofolate reductase (MTHFR). METHODS: Pregnant mice with or without a deficiency in MTHFR were fed a control diet (recommended FA intake of 2 mg/kg diet for rodents) or an FA-supplemented diet (FASD; 10-fold higher than the recommended intake [20 mg/kg diet]). At E14.5, mice were examined for embryonic loss and growth retardation, and hearts were assessed for defects and for ventricular wall thickness. RESULTS: Maternal FA supplementation was associated with embryonic loss, embryonic delays, a higher incidence of ventricular septal defects, and thinner left and right ventricular walls, compared to mothers fed control diet. CONCLUSIONS: Our work suggests that even moderately high levels of FA supplementation may adversely affect fetal mouse development. Additional studies are warranted to evaluate the impact of high folate intake in pregnant women. Birth Defects Research (Part A), 2013. © 2012 Wiley Periodicals, Inc.

Selective serotonin reuptake inhibitors and risk for major congenital anomalies.

OBJECTIVE: To estimate the risk of major congenital anomalies after exposure to selective serotonin reuptake inhibitors during pregnancy. METHODS: A retrospective cohort study based on national population-based registers (years 1996-2006) of births, congenital anomalies, and terminations of pregnancy because of severe fetal anomalies (maintained by National Institute for Health and Welfare, source offspring population n=635,583) and drug reimbursements (Social Insurance Institution) linked by a personal identification number. Offspring exposed to selective serotonin reuptake inhibitors during the first trimester (n=6,976) were compared with unexposed referent offspring. RESULTS: Overall major congenital anomalies were not more common in selective serotonin reuptake inhibitor-exposed offspring compared with unexposed referent offspring (adjusted odds ratio [OR] 1.08, 95% confidence interval [CI] 0.96-1.22). Fluoxetine was associated with an increased risk of isolated ventricular septal defects (adjusted OR 2.03, 95% CI 1.28-3.21) and paroxetine was associated with an increased risk of right ventricular outflow tract defects (adjusted OR 4.68, 95% CI 1.48-14.74). Citalopram use was associated with neural tube defects (adjusted OR 2.46, 95% CI 1.20-5.07). Fetal alcohol spectrum disorders were 10-times more common in the selective serotonin reuptake inhibitor-exposed offspring than in unexposed referent offspring. CONCLUSION: Fluoxetine use is associated with an increased risk of isolated ventricular septal defects and paroxetine is associated with right ventricular outflow tract defects. The absolute risk for these specific cardiac anomalies is small but should guide clinicians not to consider fluoxetine or paroxetine the first option when prescribing selective serotonin reuptake inhibitors to women planning pregnancy. Special attention should be given to alcohol use in pregnant women using selective serotonin reuptake inhibitors.

The effect of ascertainment bias in evaluating gestational antidepressant exposure.

Several administrative database studies have reported on a positive association between first trimester exposure to paroxetine and ventricular septal defects (VSD). Using multiple source data we have shown that depressed women utilize significantly more health care resources, including ultrasound, echocardiogram and emergency room visits for their babies. Hence, there is much higher chance to identify VSD in their babies than among healthy controls. Moreover, paroxetine has been used more specifically than other SSRI for anxiety, further increasing the chance of  ascertainment bias.

Altered cardiac function and ventricular septal defect in avian embryos exposed to low-dose trichloroethylene.

Trichloroethylene (TCE) is the most frequently reported organic groundwater contaminant in the United States. It is controversial whether gestational TCE exposure causes congenital heart defects. The basis for TCE's proposed cardiac teratogenicity is not well understood. We previously showed that chick embryos exposed to 8 ppb TCE during cardiac morphogenesis have reduced cardiac output and increased mortality. To further investigate TCE's cardioteratogenic potential, we exposed in ovo chick embryos to TCE and evaluated the heart thereafter. Significant mortality was observed following TCE exposures of 8-400 ppb during a narrow developmental period (Hamburger-Hamilton [HH] stages 15-20, embryo day ED2.3-3.5) that is characterized by myocardial expansion, secondary heart looping, and endocardial cushion formation. Of the embryos that died, most did so between ED5.5 and ED6.5. Echocardiography of embryos at ED5.5 found that TCE-exposed hearts displayed significant functional and morphological heterogeneity affecting heart rate, left ventricular mass, and wall thickness. Individual embryos were identified with cardiac hypertrophy as well as with hypoplasia. Chick embryos exposed to 8 ppb TCE at HH17 that survived to hatch exhibited a high incidence (38%, p < 0.01, n = 16) of muscular ventricular septal defects (VSDs) as detected by echocardiography and confirmed by gross dissection; no VSDs were found in controls (n = 14). The TCE-induced VSDs may be secondary to functional impairments that alter cardiac hemodynamics and subsequent ventricular foramen closure, an interpretation consistent with recent demonstrations that TCE impairs calcium handling in cardiomyocytes. These data demonstrate that TCE is a cardiac teratogen for chick.

The association between use of spermicides or male condoms and major structural birth defects.

BACKGROUND: Women may become pregnant while using contraceptives. Commonly used contraceptives containing spermicides may or may not be associated with an increased occurrence of structural birth defects. STUDY DESIGN: Utilizing data from the National Birth Defects Prevention Study, we assessed maternal reports of spermicide and male condom use 1 to 3 months following conception among case (n=11,050) and control (n=4723) mothers. We assessed the association between spermicide use and 27 types of birth defects and that between condom use and 32 types of birth defects. RESULTS: Maternal spermicide use during the first 3 months following conception was associated with a significant increase in the occurrence of only 1 of 27 birth defects, perimembranous ventricular septal defects (adjusted odds ratio=2.40, 95% confidence interval=1.25-4.62). There was no significant association between maternal use of male condoms during the first 3 months following conception and any of 32 types of birth defects. CONCLUSIONS: The increased occurrence of perimembranous ventricular septal defects among spermicide users may be real or may be a chance finding. Overall, the findings are consistent with those of most previous studies that observed no increased risk for birth defects among spermicide users.

Embryotoxicity of the artemisinin antimalarials and potential consequences for use in women in the first trimester.

Single oral doses of artesunate, dihydroartemisinin, arteether and artemether administered to rats during a sensitive period of organogenesis caused embryo deaths and malformations (malformed long bones and ventricular septal defects). Extended oral dosing (12 days or more) of monkeys once daily with 12 mg/kg-d artesunate also caused embryo deaths. The initial embryotoxic effect in both species was to kill primitive erythroblasts which are present in the embryo for a few days of gestation in rats and several weeks in primates. The malformations that occurred in rats are attributed to a transient depletion of the primitive erythroblasts. In monkeys, when treatment at 12 mg/kg-d was shortened to 3 or 7 days, the embryos survived but likely suffered a transient loss of primitive erythroblasts. Limited clinical data including 123 first trimester pregnancies have not indicated any adverse effects on pregnancy. However, in rats and monkeys, the embryonic erythroblasts are much more sensitive to artemisinins than are erythroblasts in the adult bone marrow; the latter are indicated by decreases in reticulocyte count. Since decreases in reticulocyte count occur at therapeutic doses in humans, there is reason for concern that any treatment of pregnant women during the putative sensitive period (from approximately postconception Day 21 to approximately postconception week 9) that causes even minor decreases in adult reticulocyte count could also cause a marked depletion of embryonic erythroblasts which could lead to death or malformation of the embryo.

Developmental and reproductive toxicity studies on artemisone.

BACKGROUND: In order to justify clinical studies in women of child-bearing age with artemisone, a new artimisinin derivative, studies to assess fertility and early embryonic development in rats, developmental toxicity in rats and rabbits, and peri-post natal development in rats were performed. METHODS AND RESULTS: In the study on fertility and early embryonic development (dose levels 0-5-20-80 mg/kg bw/day), doses inducing clinical and organ toxicity were used. Only in severe toxicity conditions, a reduction of the number of estruses, a prolonged time to insemination, decreased numbers of corpora lutea, implantation sites, and viable fetuses were found. Two developmental toxicity studies were performed in rats (dose levels 0-1-2 mg/kg bw/day) and rabbits (dose levels 0-2.5-5.0-7.5 mg/kg bw/day). It was shown that rats were about 5 times more sensitive than rabbits. In rats, artemisone induced total litter loss (late resorptions) at 2 mg/kg body weight and above with an increased incidence of a common vascular variation and retarded ossification at this dose. In rabbits, maternal toxicity, abortion and a slightly increased incidence of cardiac ventricular septal defects was observed at 7.5 mg/kg body weight. In a pre- and postnatal developmental toxicity study in rats (dose levels 0-1-2-4 mg/kg bw/day), 4 mg/kg body weight artemisone induced clinical symptoms and affected postnatal survival, body weight gain in the F1 pups, and motor activity. CONCLUSIONS: In summary, artemisone was shown to be embryo- and fetotoxic and induced cardiac ventricular septal defects and retarded ossification in dosages where total litter loss and abortions were observed. However, no effect on reproductive and developmental parameters below severe toxic dosages could be observed.

Congenital ventricular septal defects and prenatal exposure to cyclooxygenase inhibitors.

Ventricular septal defects (VSDs) are common congenital abnormalities which have been reported to be associated with maternal fever and various environmental factors. The aim of the present study was to evaluate the effect of prenatal exposure to cyclooxygenase (COX) inhibitors on heart defects. A retrospective statistical analysis was performed using data collected in our laboratory during various teratological studies carried out on albino CRL:(WI)WUBR Wistar strain rats from 1997 to 2004. The observations were compared with concurrent and historic control data, as well as findings from other developmental toxicological studies with selective and nonselective COX-2 inhibitors. Despite the lack of significant differences in the frequency of VSDs between drug-exposed and control groups, statistical analysis by the two-sided Mantel-Haenszel test and historical control data showed a higher incidence of heart defects in offspring exposed to nonselective COX inhibitors (30.06/10,000). Unlike other specific inhibitors, aspirin (46.26/10,000) and ibuprofen (106.95/10,000) significantly increased the incidence of the VSD when compared with various control groups (5.38-19.72/10,000). No significant differences in length or weight were detected between fetuses exposed to COX inhibitors and born with VSD and non-malformed offsprings. However, a statistically significant increase of fetal body length and decrease of body mass index were found in fetuses exposed to COX inhibitors when compared with untreated control. We conclude that prenatal exposure to COX inhibitors, especially aspirin and ibuprofen, increased the incidence of VSDs in rat offspring but was not related to fetal growth retardation.

Congenital ventricular septal defects and prenatal exposure to cyclooxygenase inhibitors

Ventricular septal defects (VSDs) are common congenital abnormalities which have been reported to be associated with maternal fever and various environmental factors. The aim of the present study was to evaluate the effect of prenatal exposure to cyclooxygenase (COX) inhibitors on heart defects. A retrospective statistical analysis was performed using data collected in our laboratory during various teratological studies carried out on albino CRL:(WI)WUBR Wistar strain rats from 1997 to 2004. The observations were compared with concurrent and historic control data, as well as findings from other developmental toxicological studies with selective and nonselective COX-2 inhibitors. Despite the lack of significant differences in the frequency of VSDs between drug-exposed and control groups, statistical analysis by the two-sided Mantel-Haenszel test and historical control data showed a higher incidence of heart defects in offspring exposed to nonselective COX inhibitors (30.06/10,000). Unlike other specific inhibitors, aspirin (46.26/10,000) and ibuprofen (106.95/10,000) significantly increased the incidence of the VSD when compared with various control groups (5.38-19.72/10,000). No significant differences in length or weight were detected between fetuses exposed to COX inhibitors and born with VSD and non-malformed offsprings. However, a statistically significant increase of fetal body length and decrease of body mass index were found in fetuses exposed to COX inhibitors when compared with untreated control. We conclude that prenatal exposure to COX inhibitors, especially aspirin and ibuprofen, increased the incidence of VSDs in rat offspring but was not related to fetal growth retardation.

Combined treatment potentiates the developmental toxicity of ibuprofen and acetazolamide in rats.

Aspirin (ASA), an irreversible cyclooxygenase (COX) inhibitor, induces ventricular septal defect (VSD) and diaphragmatic hernia (DH) in rat fetuses when administered on gestation days (GDs) 9-10, a critical period for cardiovascular (CV) and midline development. Evaluation of a spectrum of nonsteroidal antiinflammatory drugs (NSAIDs; reversible COX inhibitors) showed that while some NSAIDs induced VSD in rats, none of the NSAIDs evaluated produced DH. In addition to inhibiting COX, ASA also inhibits carbonic anhydrase. The purpose of this study was to determine whether concurrent inhibition of COX and carbonic anhydrase would produce a teratogenic profile that includes both VSD and DH. To inhibit both COX and carbonic anhydrase, ibuprofen (COX inhibitor) and acetazolamide (carbonic anhydrase inhibitor) were coadministered on GDs 9-10. Groups of 20 female Crl:CD(SD)IGS BR rats were given either 300 mg kg(-1) day(-1) ibuprofen, 1000 mg kg(-1) day(-1) acetazolamide, or both (combination of ibuprofen and acetazolamide). Fetuses were evaluated on GD 21 for external and visceral development. Ibuprofen induced VSD in 3.7% of fetuses per litter; no defects in appendicular skeletal development were noted. Acetazolamide induced VSD in 5.9% of the fetuses per litter and appendicular defects in 41% of the fetuses per litter. Coadministration of ibuprofen and acetazolamide produced VSD in 18.7% of the fetuses per litter and appendicular defects in 77% of the fetuses per litter; however, there were no DH. Therefore, while concurrent inhibition of COX and carbonic anhydrase did not produce DH, potentiation was noted for the induction of VSD and appendicular anomalies.

Improved technique for fetal heart examination in developmental toxicity studies in rats.

Bouin's or a 10% formalin solution has been used to fixate internal fetal observations for developmental toxicity studies in rats. However, these fixatives are known to cause contraction of the ventricle of the heart and arteries, which makes dissection and observation more difficult. Fetuses on day 20 of gestation from pregnant Crj:CD(SD)IGS rats were injected with 10 w/v% magnesium chloride/10 vol% neutral buffered formalin solution into the thoracic cavity, and then fixed in 10 vol% neutral buffered formalin. After fixation, the heart was dissected using a modified Staples technique. In treated fetuses, the membranous region of the ventricular septum and the valves were clearly observed in an expanded state. We conclude that this method increases the ability to detect heart anomalies and decreases the chance of a false-positive finding.