Pre- and post-conceptional tobacco effects on the CD-1 mouse fetus

The objective of this study was to examine the effect of subchronic administration of an aqueous extract of smokeless tobacco (ST) on the development of the CD-1 mouse fetus. Mice were administered ST for approximately 5 weeks: for 2 weeks prior to breeding, during breeding, and during gestational days 0 to 17. Thus the initial peak nicotine levels occurred prior to breeding and not during the critical periods of gestation. Two ST dosages were administered by gastric intubation three times daily: ST/D-1, equivalent to a dose of 12 mg nicotine/kg of body weight, and ST/D-2, equivalent to 20 mg nicotine/kg body weight. Maternal plasma nicotine levels were determined 30 min after the second intubation during the pretreatment and gestational phases of treatment. At these ST dosages, the weight gain of ST-treated dams was not significantly affected in comparison to treated controls. The mean maternal plasma nicotine level for the low-dosage group was 363 ng/ml, and 481 ng/ml for the high-dosage group, with maternal lethality observed at 9.6% and 28.2%, respectively. No significant differences were seen between control and ST/D-1 maternal and/or fetal values, except for placental weights which were heaviest in the ST group (P less than 0.05). Several differences were noted between the ST/D-2 group and controls: fetal weights were reduced by 5.4% (P less than 0.05); decreased ossification was seen in femur measurements and in nine of ten characteristics measured (P less than 0.05); the frequency of resorptions (7.6%) was almost doubled (controls 4.2%); and the frequency of deaths and malformations was not affected. Under these experimental conditions, the low dose produced a negligible effect on the CD-1 mouse fetus and the dam. The high dose demonstrated growth retardation (P less than 0.05), increased embryotoxicity, and a significant decrease in ossification (P less than 0.05).     

Alcohol and smokeless tobacco effects on the CD-1 mouse fetus.

Tobacco products and alcohol are commonly used as nonmedicinal drugs by pregnant women, and both are known to cause various effects on the fetus and the newborn. The objective of this study was to examine the fetal effects of both drugs when administered individually and simultaneously to pregnant CD-1 mice at moderate dosages. Specifically, we wanted to determine whether or not the effect on the fetus of these two biologically active substances was additive, ameliorative, or synergistic. A total of 65 CD-1 dams were divided among four groups receiving either ST equivalent to 8 mg/kg nicotine, ethanol (ETOH) 1.8 g/kg, a combination of ST+ETOH in the same dosages, or D-glucose (controls and ST alone) to supply calories equivalent to the dose of ethanol. Mice were dosed three times per day on gestational days 6-15. On gestational day 17 all dams were killed, fetal and placental weights recorded, and the number of resorbed, dead, and malformed fetuses noted. The mean maternal plasma drug levels were: nicotine-321 ng/ml and ethanol-0.105 g%. No significant differences were observed in maternal weight gain, litter size, or in the incidence of resorptions, deaths and/or malformations. Fetal weights were reduced in all three treatment groups (P less than 0.05), with the greatest reduction (13% decrease) recorded in the ST group, followed by a 9% decrease in the ETOH group, and a 7% decrease in the ST+ETOH group. Placentas of the ST group weighed significantly less (P less than 0.05) than controls. Ossification of the fetal skeleton, observed in ten sites, was affected to the greatest extent in the ST group, followed by the ETOH and ST+ETOH groups. Craniofacial measurements were significantly affected (P less than 0.05) in all three treatment groups, compared to controls. We conclude that under these experimental conditions, in terms of fetal growth and ossification, ST had the greatest effect, followed by ETOH and ST+ETOH. The interaction of ST+ETOH was neither additive, synergistic, nor ameliorative.     

Methanol exposure during gastrulation causes holoprosencephaly, facial dysgenesis, and cervical vertebral malformations in C57BL/6J mice

BACKGROUND: Exposure of pregnant outbred CD-1 mice to methanol during the period of gastrulation results in exencephaly, cleft palate, and cervical vertebra malformations [Rogers and Mole, Teratology 55: 364, 1997], while inbred C57BL/6J mice are sensitive to the teratogenicity of ethanol. C57BL/6J fetuses exhibit the holoprosencephaly spectrum of malformations after maternal exposure to ethanol during gastrulation, but the sensitivity of C57BL/6J mice to methanol-induced teratogenesis has not been previously described. METHODS: Pregnant C57BL/6J mice were administered two i.p. injections totaling 3.4 or 4.9 g/kg methanol or distilled water four hrs apart on gestation day 'GD' 7. On GD 17, litters were examined for numbers of live, dead and resorbed conceptuses, fetuses were weighed as a litter and examined externally, and all fetuses were double stained for skeletal analysis. RESULTS: No maternal intoxication was apparent, but the high dosage level caused a transient deficit in maternal weight gain. The number of live fetuses per litter was reduced at both dosages of methanol, and fetal weight was lower in the high dosage group. Craniofacial defects were observed in 55.8% of fetuses in the low dosage group and 91.0% of fetuses in the high dosage group, including micro/anophthalmia, holoprosencephaly, facial clefts and gross facial angenesis. Skeletal malformations, particularly of the cervical vertebrae, were observed at both dosages of methanol, and were similar to those previously reported in the CD-1 mouse following methanol exposure. CONCLUSIONS: The types of craniofacial malformations induced in the C57BL/6J mouse by methanol indicate that methanol and ethanol have common targets and may have common modes of action.     

Teratogenic effects on the CD-1 mouse embryo exposed to concurrent doses of ethanol and aspirin

Human fetal alcohol syndrome characteristics have been seen in the mouse fetus by several investigators who dosed the dam with only one or two doses of alcohol. The purpose of this study was to determine if the fetal effects of acute doses of alcohol (ethanol) are altered by aspirin. CD-1 mice were given two IP doses of a 25% v/v solution of 95% ethanol/saline (2.5 hours apart) and intubated with 250 mg/kg aspirin. The treatment regimen, begun at 8 days, 4 hours gestation, consisted of either aspirin pretreatment 1 hour before or posttreatment 1 hour after the ethanol. Control animals were treated similarly and included vehicle only, ethanol/vehicle, and aspirin/vehicle groups. One group was untreated. On gestational day 18, the dams were killed and the uterine horns were examined for live, dead, and resorbed fetuses. The live were weighed and examined for external malformations and either skeletal or visceral abnormalities. With the litter as the unit of analysis, no significant difference was found in the number of dead and resorbed among groups. There was a significant difference (P less than .01) in average fetal weight in the aspirin-pretreated group. When the total number of fetuses affected was considered, the aspirin pretreatment group showed significantly (P less than .05) more external and visceral malformations. The skeletal examination revealed a significant (P less than .05) difference in anomalies plus delayed ossification in both groups treated with the aspirin/ethanol combination. No significant differences were seen in any category in the groups receiving aspirin alone or ethanol alone. These results indicate an additive effect of aspirin and ethanol on the developing CD-1 mouse fetus.     

Effects of sodium valproate and oxygen on the CD-1 mouse fetus

This study reports the effects of valproic acid (VA) on the CD-1 mouse fetus when the drug is administered continuously via osmotic minipumps at human therapeutic drug plasma levels. Two VA-filled Alzet osmotic minipumps were implanted subcutaneously on gestation day 5 for continuous exposure of a total daily dosage of 850 mg/kg on gestation days 5-12. Dams were then exposed continuously to either normoxic (21% oxygen), hyperoxic (50% oxygen), or hypoxic (12% oxygen) controlled environments during gestation days 5-12, in order to determine if hyperoxic maternal conditions offered a protective environment for the fetus, and conversely, if hypoxia exacerbated teratogenicity. Dams were sacrificed on gestation day 18, and litter and fetal data were collected. It was determined in separate groups under normoxic conditions that the osmotic minipump system maintained VA plasma levels corresponding to human therapeutic levels. Sodium valproate was found to induce developmental toxicity in the CD-1 mouse fetus at human therapeutic drug plasma levels. Fetal weights were reduced, and the number of resorptions, deaths, and hematomas was increased. While hypoxia exacerbated the toxic effect on the fetus, hyperoxia failed to ameliorate the outcome.     

Teratogenic effects of nicotine on palate formation in mice

Fetuses of pregnant CD-1 mice, exposed to intraperitoneal injection of 0.1% nicotine sulfate at a dose of 1.67 mg/kg body weight/day on gestational days 6-15, were compared with control (saline injected and non-injected) fetuses to assess the effects of nicotine on fetal growth in general and palatogenesis in particular. A total of 59 pregnant females (18 experimental and 41 control) were sacrificed on the 18 th gestational day and their fetuses were examined gross morphologically and histologically (using serial sections through the head in the frontal plane). Data analysis revealed that maternal weight gain, crown-rump length, fetal weight and head dimensions were significantly reduced in nicoted treated animals when compared to those of the controls. Histological examination revealed that 9.6% of fetuses of nicotine injected mothers presented clefts of the palate, whereas none of the control fetuses had that anomaly. It was concluded that nicotine has a detrimental effect on general growth and development as well as on palatogenesis of mice.     

Morphometric analysis of the craniofacial development of the CD-1 mouse fetus exposed to alcohol on gestational day eight

Fetal alcohol syndrome (FAS) describes a pattern of dysmorphogenesis observed in some offspring of women who consumed alcohol during pregnancy; partial expression of this pattern are fetal alcohol effects (FAE). The purpose of this investigation was to measure selected craniofacial parameters in the CD-1 mouse fetus following exposure to alcohol on gestational day (D) 8. CD-1 mice were mated for 1 hr; D0.0 designated by the presence of a vaginal plug. On D8, 0 hr, and D8, 4 hr, 33 dams were injected intraperitoneally (IP) with 25% (v/v) alcohol in physiological saline solution (0.015 ml/gm maternal body weight). Appropriate controls were maintained. The animals were sacrificed every 12 hr from D12.0 through D17.0. Implantation sites were examined and recorded as live, dead, or resorbed fetuses. All live fetuses were weighed, examined for gross defects, and fixed in Bouin's solution. Twenty-three bilateral parameters were recorded for linear dimensions defining face and cranium. The fetal weights were statistically lower in treated as compared to control fetuses only on D16.0 through D17.0. Statistical analysis of the morphometrics identified five distinct growth patterns in treated mice as compared to controls. The anomalies induced in the CD-1 mouse fetus following exposure to alcohol on D8.0 resembled FAE rather than FAS. Morphometric analysis of the craniofacial region may be an important clinical tool for the quantitative identification of alcohol-related effects in the offspring of women who consumed alcohol while pregnant.     

Teratogenicity of carbamazepine in rats

The teratogenicity of carbamazepine (CBZ) was investigated in Sprague-Dawley CD rats at doses of 0, 200, 400, and 600 mg/kg administered by gavage in corn oil on days 7-18 of gestation in a dosage volume of 2 ml/kg. The CBZ-600 dose was maternally toxic in that dams in this group weighed 30.6% less than controls by E20. This group had significantly increased resorptions, reduced live fetal weight (51.6% less than controls), and increased skeletal and visceral abnormalities. The CBZ-400 dose also significantly reduced maternal weight gain during gestation to 26.6% less than controls by E20. No significant increase in resorptions occurred in this group; live fetuses weighted 42.9% less than controls and showed an increase in visceral, but not skeletal, abnormalities. The CBZ-200 dose did not significantly affect maternal weight gain or increase resorptions or fetal abnormalities but did reduce fetal body weight (20.3% less than controls). Maternal serum total CBZ concentrations 1 hr after the final dose were 22.9, 27.9, and 34.4 micrograms/ml for the 200, 400, and 600 mg/kg groups, respectively. These levels were little changed 6 h post-treatment. CBZ was 65-70% serum protein bound across dose groups. Human therapeutic levels of CBZ are 4-12 micrograms/ml and the drug is typically 80% serum protein bound. This suggests that abnormalities in rats occur at concentrations well above the human therapeutic range. However, a no-effect level was not found for fetal body weight. Further experiments will be required to determine how much lower doses will need to be in order to find a no-effect level for fetal body weight. Nevertheless, the present data suggest that CBZ is not potent at inducing malformations in rats.     

氧化石墨烯对黑麦草根系抗逆生理特性的影响

该研究通过向土壤中添加不同含量(1%、2%、3%、4%和5%)的氧化石墨烯(graphene oxide,GO),分析其对黑麦草根系生长及抗逆生理特性的影响。结果表明：(1)低剂量(1%和2%)的GO对黑麦草根系生长没有显著影响,高剂量(3%～5%)的GO处理显著抑制了黑麦草根系生长。(2)1% GO处理对根体积和根生物量没有影响,随着GO添加量的增加,黑麦草根体积和根生物量逐渐减小,在5% GO处理下,降至最低,根干重较对照降低了22.64%。(3)1% GO处理对黑麦草根保护酶活性与丙二醛(MDA)含量影响不显著,随着GO添加量的增加,过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性显著高于对照组,且MDA含量也显著增加,说明GO对黑麦草根系生长产生了氧化胁迫。(4)GO处理超过1%时黑麦草根系活力显著下降,并于5% GO处理下根系活力降至最小,较对照下降了35.07%。研究认为,低剂量(1%~2%)的GO对黑麦草的生长没有影响,而高剂量GO则会对根系产生明显的氧化胁迫,从而造成根系损伤。     

Effects of Ginkgo biloba extract on the embryo‐fetal development in Wistar rats

BACKGROUND: Ginkgo biloba extract (GBE) is an herbal medicine used for treating neurodegenerative diseases, cerebrovascular insufficiency, peripheral arterial occlusive disease, and also vestibular disturbance. Some components of GBE have presented estrogenic effects and, in a previous study, high dosages of GBE caused intra‐uterine growth retardation in fetuses of Wistar rats treated during the fetogenesis period. METHODS: Pregnant Wistar rats were treated, through gavage, with different dosages of aqueous GBE (3.5, 7.0, and 14.0 mg/Kg/day), during the tubal transit and implantation period. Rats were killed on the 15th day of pregnancy and the following parameters were evaluated: clinical symptoms of maternal toxicity; maternal body weight; feed and water intake; maternal liver, kidney, and ovary weights; number of corpora lutea; implants per group ratio; pre‐ and post‐implantation loss per group ratio; live fetuses mean; dead fetuses percentage; fetus and placenta weight per offspring ratio; and fetal external malformation. RESULTS: No significant alteration was found for both the maternal and embryonic parameters evaluated. CONCLUSIONS: The GBE treatment in pregnant Wistar rats, during the tubal transit and implantation period, caused no toxic effect on the maternal organism and did not induce embryonic death, growth retardation, and/or fetal malformations. Birth Defects Res (Part B) 89:133–138, 2010. © 2010 Wiley‐Liss, Inc.     

Threshold levels of maternal nicotine impairing protective responses of newborn rats to intermittent hypoxia.

Experiments were carried out to determine the threshold level of maternal nicotine that impairs protective responses of rat pups to hypoxia. From days 6 or 7 of gestation, pregnant rats received either vehicle or nicotine (1.50, 3.00, or 6.00 mg of nicotine tartrate. kg body wt(-1).day(-1)) or vehicle continuously via a subcutaneous osmotic minipump. On postnatal days 5 or 6, pups were exposed to a single period of hypoxia produced by breathing an anoxic gas mixture (97% N(2) or 3% CO(2)) and their time to last gasp was determined, or they were exposed to intermittent hypoxia and their ability to autoresuscitate from hypoxic-induced primary apnea was determined. Perinatal exposure to nicotine did not alter the time to last gasp or the total number of gasps when the pups were exposed to a single period of hypoxia. The number of successful autoresuscitations on repeated exposure to hypoxia was, however, decreased in pups whose dams had received either 3.00 or 6.00 mg of nicotine tartrate/kg body wt; these dosage regimens produced maternal serum nicotine concentrations of 19 +/- 6 and 35 +/- 8 ng/ml, respectively. Thus our experiments define the threshold level of maternal nicotine that significantly impairs protective responses of 5- to 6-day-old rat pups to intermittent hypoxia such as may occur in human infants during episodes of prolonged sleep apnea or positional asphyxia.     

Lack of teratogenicity of trans-2-ene-valproic acid compared to valproic acid in rats

The teratogenicity of trans-2-ene-valproic acid (300 and 400 mg/kg) was compared with that of valproic acid (VPA; 300 mg/kg) and controls (corn oil) administered by gavage to Sprague-Dawley CD rats on embryonic (E) days 7-18. At the 300 mg/kg dose, trans-2-ene-VPA produced no change in maternal weight, number of implantations, proportion of resorptions, proportion of malformations, or fetal weight. By contrast, the same dose of VPA (300 mg/kg) reduced maternal weight during gestation, increased malformations (12.0% vs. 0.7% in controls), and reduced fetal body weight by 25.1%. An even higher dose of trans-2-ene-VPA (400 mg/kg) produced a reduction in maternal body weight during treatment and reduced fetal body weight (by 7.9%), but did not increase resorptions or malformations in the fetuses. On day E18, maternal serum drug concentrations of VPA were higher in the VPA-treated group compared with those of trans-2-ene-VPA in the trans-2-ene-VPA-treated groups at 1 hr posttreatment. At 6 hr posttreatment the reverse was seen. trans-2-ene-VPA may be absorbed more rapidly and distributed differently than VPA. Overall, the data support the view that trans-2-ene-VPA at equal or higher doses than VPA is not teratogenic in rats.     

Teratogenic effects of dosage levels and time of administration of carbamazepine, sodium valproate, and diphenylhydantoin on craniofacial development in the CD-1 mouse fetus

The objective of this investigation was to study the teratogenic effects of dosage levels and time of administration of three anticonvulsant drugs (carbamazepine [CMZ], sodium valproate [NaV], and diphenylhydantoin [DPH]) on craniofacial development in the CD-1 mouse fetus. Pregnant females were intubated on each of days 8-10, 11-13, 14-16, and 8-16 of gestation with the following dose levels for each drug: 375, 563, 938 mg/kg CMZ; 225, 338, 563 mg/kg NaV; 50, 75, 125 mg/kg DPH. Appropriate control groups were maintained for each drug. On gestation day 17, pregnant females were killed and implantation sites were recorded as live, dead, or resorbed. All live fetuses were examined for craniofacial defects. Results of examination of 1,398 fetuses indicated that CMZ, NaV, and DPH were teratogenic and embryotoxic at all dose levels. This study indicated that the observed decrease in mean fetal weight was drug-, dose-, and time-dependent. There was a drug-, dose-, and time-dependent increase observed in the number of dead fetuses, whereas the number of resorbed fetuses was observed to be only time-dependent. The observed frequencies of hydrocephalies, secondary palatal clefts, and submucous palatal clefts were significant for all three factors (drug, dose, and time) whereas the observed frequencies of hematomas and exencephalies were significant only for drug and time. Cleft lips were observed only in the highest dose level of DPH. Uterine horn distribution of defects indicated that fetuses located at the proximal end of the horns were less subject to major defects than those fetuses located at the distal end of the uterine horns. Fetuses with craniofacial hematomas were found in the proximal one-third of the uterine horn, resorbed fetuses, and fetuses with submucous palatal clefts in the middle one-third of the uterine horns and dead fetuses and fetuses with exencephalies, cleft lips, and secondary palatal clefts were localized in the distal one-third of the uterine horns. In comparing the effect of drug, dosage, and time on the development of craniofacial malformations in the CD-1 mouse fetus, CMZ was the least teratogenic and embryotoxic of the three anticonvulsant drugs employed in this study.     

Embryotoxicity of sex steroidal hormone combinations in nonhuman primates: I. Norethisterone acetate + ethinylestradiol and progesterone + estradiol benzoate (Macaca mulatta, Macaca fascicularis, and Papio cynocephalus)

Two sex steroid hormone combinations which have been used clinically as tests for detection of early pregnancy were examined for embryotoxic effects in macaques and baboons. Norethisterone acetate and ethinyl estradiol (NEA + EE) were orally administered to rhesus and cynomolgus monkeys and baboons at dosages ranging from one to 1,000 times the human dose equivalent (HDE) during days 20-50 of pregnancy. Progesterone and estradiol benzoate (P + EB) were delivered by two to six intramuscular injections to rhesus and cynomolgus monkeys between gestational days 20 and 35 at 0.1-25 X HDE. Fetuses were examined following cesarean section at 100 +/- 2 days (NEA + EE) or at term (P + EB). The results showed increased embryolethality over controls at 100-1,000 X HDE (NEA + EE) and at 10 and 25 X HDE (P + EB). Besides growth retardation, isolated cases of minor nongenital malformations were observed only in cynomolgus monkeys following treatment with both hormone combinations mainly at embryolethal dose levels and were considered spontaneous in nature. Virilization of female cynomolgus fetuses following NEA + EE treatment was manifested as two cases of clitoral enlargement in the 300 X HDE group and two cases of increased anogenital distance with reduced vaginal opening in the 1,000 X HDE group. The highest dose of NEA + EE was also maternally toxic, as two maternal deaths occurred at the end of the treatment period. One dead female cynomolgus fetus exposed to P + EB (10 X HDE) also exhibited masculinized external genitalia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Teratogenicity of all-trans retinoic acid during early embryonic development in the cynomolgus monkey (Macaca fascicularis).

The embryotoxic and teratogenic potential of all-trans retinoic acid was assessed following exposure prior to and during early organogenesis in the cynomolgus monkey (Macaca fascicularis). Sixteen pregnant females were orally administered all-trans retinoic acid (Tretinoin, Hoffmann-La Roche) once daily from GD 10-20 and twice daily from GD 21-24 at three different dosages, 5 (n = 9), 10 (n = 6) and 20 mg/kg (n = 1). Adverse clinical signs resembling hypervitaminosis A were observed in one animal at 5 mg/kg, in three animals at 10 mg/kg, and in the animal treated with 20 mg/kg all-trans retinoic acid. Maternal weight loss was observed in the 10- and 20-mg/kg groups. A dose-dependent increase in embryolethality was observed, with 22% (2/9), 50% (3/6), and 100% (1/1) occurring at 5, 10, and 20 mg/kg, respectively. The majority of embryonic deaths occurred between GD 16 and 20; the incidence of these early losses was higher than in historical and concurrent controls. No malformations, but a single growth-retarded fetus, was observed in the 5-mg/kg group. Craniofacial malformations, consisting of external ear defects, mandibular hypoplasia, cleft palate, and temporal bone abnormalities, were seen in three viable fetuses in the 10-mg/kg group. Skeletal variations were common to the majority (70%, 7/10) of viable fetuses in both dose groups and were increased relative to historical controls (32%, 25/77). Unlike previous studies with 13-cis-retinoic acid during the pre- and early organogenic stages of development (Hummler et al., Teratology 42:263-272, 1990), no thymic hypo- or aplasia or heart anomalies were observed, which may be attributable to the slightly longer 13-cis retinoic acid treatment period, i.e., GD 10-27. However, external ear and temporal bone defects were common to both all-trans and 13-cis retinoic acid. The similarity observed in the malformation syndrome induced by both all-trans and 13-cis retinoic acid in the cynomolgus monkey and 13-cis retinoic acid embryopathy in humans supports this macaque species as a model for further developmental toxicity studies of vitamin A-related compounds.     

The molecular weight of sodium hyaluronate in amniotic fluid

The molecular weight of sodium hyaluronate in human amniotic fluid was determined by gel chromatography. Pooled samples from 16 weeks of gestation exhibited a broad molecular weight distribution (Mw = 3 X 10(5); Mn = 6 X 10(4)). Samples taken at 40 weeks showed a low molecular weight fraction (M less than 10(5) presumably of fetal origin, and a high molecular weight fraction (M greater than 10(6) which varied considerably, indicating a nonfetal origin. No hyaluronate degrading activity was detected in the fluid. In a case of renal dysplasia, only minute amounts of hyaluronate were found. These findings are in accordance with a renal excretion of a low molecular weight hyaluronate from the fetus. In 12 cases with proven neural tube defects, there was no significant difference in hyaluronate level and molecular weight compared to normal controls.     

Developmental toxicity of carbon black oil in mice

BACKGROUND: Carbon black oil (CBO) is a refinery side-stream product used to produce asphalt and other commercial products. CBO contains several classes of hydrocarbons, several of which are known to exhibit systemic and gestational toxicities, making this mixture a candidate for causing reproductive toxicity. METHODS: Swiss-Webster mice were administered CBO (300, 350, 400 mg/kg/day) via oral gavage in a dosage volume of 10 microl/g body weight on gestation days (GD) 6-15. Uterine contents were evaluated on GD 18. RESULTS: Treatment with CBO at all dosage levels resulted in a high frequency of maternal clinical symptoms and a decrease in maternal weight gain. Decreased fetal viability was observed, manifested as a decrease in viable implants and, in a high percentage of treated dams, as early resorption of the entire litter. A significant reduction in fetal weight was also observed. However, neither structural malformations nor developmental delays in ossification were observed in any of the living offspring. To minimize maternal toxicity, the dosage range was lowered (100, 200, 300 mg/kg/day), and the concentration was adjusted such that the volume administered to each dam was decreased by 20%. In this trial, the only maternal effect observed was an increase in maternal liver weight at 200 and 300 mg/kg. The fetal lethality effects observed previously were reduced substantially. Nevertheless, the frequency of resorption among all treatment groups was higher statistically than in controls. CONCLUSIONS: These data support the hypothesis that CBO is reproductively toxic in Swiss-Webster mice at oral doses of >/=100 mg/kg/day.     

A Case-Control Study of Maternal Periconceptual and Pregnancy Recreational Drug Use and Fetal Malformation Using Hair Analysis

Objective

Maternal recreational drug use may be associated with the development of fetal malformations such as gastroschisis, brain and limb defects, the aetiology due to vascular disruption during organogenesis. Using forensic hair analysis we reported evidence of recreational drug use in 18% of women with a fetal gastroschisis. Here we investigate this association in a variety of fetal malformations using the same method.

Methods

In a multi-centre study, women with normal pregnancies (controls) and those with fetal abnormalities (cases) gave informed consent for hair analysis for recreational drug metabolites using mass spectrometry. Hair samples cut at the root were tested in sections corresponding to 3 month time periods (pre and periconceptual period).

Results

Women whose fetus had gastroschisis, compared to women with a normal control fetus, were younger (mean age 23.78±SD4.79 years, 18–37 vs 29.79±SD6 years, 18–42, p = 0.00001), were more likely to have evidence of recreational drug use (15, 25.4% vs 21, 13%, OR2.27, 95^thCI 1.08–4.78, p = 0.028), and were less likely to report periconceptual folic acid use (31, 53.4% vs 124, 77.5%, OR0.33, 95^thCI 0.18–0.63, p = 0.001). Age-matched normal control women were no less likely to test positive for recreational drugs than women whose fetus had gastroschisis. After accounting for all significant factors, only young maternal age remained significantly associated with gastroschisis. Women with a fetus affected by a non-neural tube central nervous system (CNS) anomaly were more likely to test positive for recreational drugs when compared to women whose fetus was normal (7, 35% vs 21, 13%, OR3.59, 95^th CI1.20–10.02, p = 0.01).

Conclusions

We demonstrate a significant association between non neural tube CNS anomalies and recreational drug use in the periconceptual period, first or second trimesters, but we cannot confirm this association with gastroschisis. We confirm the association of gastroschisis with young maternal age.     

Mechanism of dimethylsulfoxide protection against the teratogenicity of secalonic acid D in mice

Dimethylsulfoxide (DMSO) is known to antagonize the teratogenic effects of secalonic acid D (SAD) in mice. To establish the optimum protective dose of DMSO, pregnant CD-1 mice were treated, i.p., with 30 mg/kg of SAD in 5% (w/v) NaHCO3, containing 0, 10, 20, or 30% (v/v) DMSO on day 11 of gestation. Data indicate that at 10% and 20% levels, DMSO affords an apparent dose-related protection against SAD-induced cleft palate, whereas 30% DMSO enhanced fetal resorption with no reduction in the incidence of cleft palate. Ultraviolet spectra and TLC mobility indicated that DMSO at 20% did not directly interact with SAD. Distribution and elimination of 14C-SAD was studied in fetal and maternal tissues from pregnant mice at 24 and 48 hr after exposure to 30 mg/kg of 14C-SAD, i.p., in NaHCO3 (control) or in 20% DMSO. Compared with those not receiving DMSO, maternal exposure to DMSO: 1) significantly reduced (42-75%) radioactivity in fetal heads and bodies, placenta, and maternal tissues other than liver; 2) significantly increased (up to 222%) the radioactivity in maternal liver; and 3) significantly reduced (44-58%) fecal and urinary elimination of SAD-derived radioactivity. These results suggest that the antiteratogenic effect of DMSO against SAD may be at least partly mediated by increased SAD (or its metabolites) retention by maternal liver leading to reduced SAD uptake by the fetus.     

Hypervitaminosis A resulting in DNA aberration in fetal transgenic mice (Muta Mouse)

Treatment with excessive amounts of Vitamin A during maternity induces fetal malformations. However, it is unclear whether these malformations are due to gene mutations or not. Using transgenic mice (containing lacZ gene showing beta-galactosidase enzymatic activity), we planned to observe whether gene mutations occur in the fetal tissues after treatment during maternity with Vitamin A (retinol palmitate). On the 11th day of pregnancy, mothers were given 30 mg (group 2), 150 mg (group 3) and 300 mg (group 4) of Vitamin A/kg body weight orally. Fetuses obtained on the 18th day of gestation showed malformations, such as cleft palate, origodactyly, brachydactyly and ectromeria. Most notably, cleft palate occurred dose dependently. The incidental rates were 100% in group 4, 58% in group 3 and 6% in group 2. The number of dead and absorbed fetuses also increased dose dependently with the treatments. DNA (integrated vectors containing lacZ genes) extracted from each fetus showed Vitamin A-induced lacZ mutations, especially in the malformed fetuses. The mutation frequencies were 4.99x10(-5) in group 4, 5.28x10(-5) in group 3 and 4.26x10(-5) in group 2. The frequencies of group 3 were significantly higher (p<0.05) than that of the controls (group 1), 2.79x10(-5). Maternal treatment with Vitamin A (150 mg/kg of body weight) was carried out on the 11th day of pregnancy. Fetuses obtained on the 14th day of gestation showed a much higher incidence of mutation, approximately 8.91x10(-5) (group 6) that was significantly higher (p<0.0001) than those from the controls (group 5), 2.94x10(-5). The present study indicates a possibility that hypervitaminosis A-induced fetal malformation and death might be caused by gene mutations.