Neuroblastoma after prenatal exposure to phenytoin: cause and effect?

We evaluated the causality of the association between intrauterine exposure to phenytoin and postnatal neuroblastoma using an in vitro lymphocyte toxicity assay for phenytoin-induced reactions in an unusual sibship. In addition, we investigated intrauterine phenytoin exposure in a case series of infants and children with neuroblastoma diagnosed over 17 years at our center. The response of lymphocytes from our index case with neuroblastoma exposed in utero to phenytoin was within the normal range, whereas the mother and a sibling with fetal hydantoin syndrome (FHS) exhibited an intermediate toxicity. None of the 188 cases of childhood neuroblastoma diagnosed between 1969 and 1988 had been exposed in utero to phenytoin, indicating that, statistically, the drug cannot be associated with neuroblastoma in more than two cases with this malignancy in our cohort, or in 1.5% of all cases of neuroblastoma. Although our data do not suggest an association between phenytoin in pregnancy and postnatal neuroblastoma, it is still possible that there is an increased risk for neuroblastoma in children with FHS.     

Anticonvulsant action of di-N-propylacetate combined with benzodiazepines, phenobarbital and phenytoin

The combined use of di-n-propylacetate with phenazepam, diazepam, phenobarbital or phenytoin was shown to be followed by reciprocal potentiation of the anticonvulsant activity of the drugs in a variety of experimental epileptic seizures in mice according to the tests of shock and antagonism with corasole and thiosemicarbazide. The potentiating effect of the subthreshold dose of di-n-propylacetate on anticonvulsant effects of benzodiazepines, phenobarbital and phenytoin was more pronounced than the effect of the drugs administered in the subthreshold doses on the anticonvulsant activity of di-n-propylacetate. Of both combinations, di-n-propylacetate plus benzodiazepines proved to be most efficacious one. The unidirectional effect of the combined drugs on the different stages of the development of GABA-ergic system inhibitory function in the CNS activity is assumed to be of importance in the mechanism of reciprocal potentiation.     

Effects of prenatal exposure to styrene trimers on genital organs and hormones in male rats

Styrene trimers migrate from polystyrene food container into foods. We evaluated the estrogenic activity of styrene trimers such as 2,4,6-triphenyl-1-hexene (ST-1), 1a-phenyl-4a-(1'-phenylethyl)tetralin (ST-2), 1a-phenyl-4e-(1'-phenylethyl)tetralin(ST-3), 1e-phenyl-4a-(1'-phenylethyl)tetralin (ST-4), and 1e-phenyl-4e-(1'-phenylethyl)tetralin (ST-5) using the reporter-gene assay with MVLN cells stably expressing the estrogen-stimulated reporter gene, and it was confirmed that ST-1, ST-3, and ST-4 had estrogen-like activity. On the other hand, ST-2 and ST-5 had anti-estrogen-like activity. We examined the estrogenic activity in vivo of ST-1, ST-3, and ST-4. The styrene trimers were administered to pregnant rats, and the effects on the offspring were examined. ST-1, ST-3, or ST-4 (0, 10, 100, 1000 microg/kg body wt/day) were subcutaneously injected into pregnant rats from gestational Day 11 through 17, and the male offspring were sacrificed on postnatal days (PND) 101-103. In the ST-4 treatment groups, the relative anogenital distance on PND 3 was significantly shortened. The relative testis weight was remarkably decreased in all styrene trimer treatment groups. Relative weights of the prostate and epididymides significantly decreased in the ST-4 treatment groups. The relative brain weight was markedly reduced in the ST-3 and ST-4 treatment groups. A significant decrease of the Sertoli cell count was observed in the ST-1 and ST-4 treatment groups. The serum follicle stimulating hormone level was remarkably reduced in all styrene trimer treatment groups. The luteinizing hormone level was significantly decreased and the testosterone level increased in the ST-1 and ST-4 groups. These results suggest that prenatal exposure to estrogenic styrene trimers at low levels obstructed genital organ development, and disrupted the endocrine systems of male rat offspring.     

Women's genital sexual arousal to oral versus penetrative heterosexual sex varies with menstrual cycle phase at first exposure

Reproductive-aged women show increased interest in sexual activity during the fertile phase of the menstrual cycle that can motivate sexual behavior and thereby increase the likelihood of conception. We examined whether women demonstrated greater sexual responses (subjective and genital sexual arousal) to penetrative versus oral sexual activities during the fertile versus non-fertile phases of their cycles, and whether women's arousal responses were influenced by the phase during which they were first exposed to these sexual stimuli (e.g., Slob et al., 1991; Wallen and Rupp, 2010). Twenty-two androphilic women completed two identical sexual arousal assessments in which genital responses were measured with a vaginal photoplethysmograph and their feelings of sexual arousal were recorded. Women viewed an array of 90 s films varying by couple type (female–female, male–male, female–male) and sexual activity type (oral or penetrative), during the fertile (follicular) and non-fertile (luteal) phases of their menstrual cycle, with the order of cycle phase at the first testing session counter-balanced. Women tested first in the fertile phase showed significantly greater genital arousal to female–male penetrative versus oral sex in both testing sessions, whereas self-reports of sexual arousal were not affected by cycle phase or testing order. These results contribute to a growing body of research suggesting that fertility status at first exposure to sexual stimuli has a significant effect on subsequent sexual responses to sexual stimuli, and that this effect may differ for subjective versus genital sexual arousal.     

Effect of prenatal diazepam, phenobarbital, haloperidol and fluoxetine exposure on foot shock induced aggression in rats.

Different groups of pregnant rats were treated with diazepam (10 mg/kg), phenobarbital (10 mg/kg), haloperidol (0.1 mg/kg), fluoxetine (10 mg/kg) and vehicle (normal saline) intraperitoneally once a day during gestation days 13 to 21. After birth these pups were culled to 8 pups/dam and foster-nursed by lactating mothers for 3 weeks and were reared in colony cages thereafter. Sex and weight matched pairs of rat offsprings were subjected to foot shock induced aggression test at 8 weeks of age. Two parameters of aggressive behaviour were recorded namely, the latency to fight and total number of fighting bouts. The results indicate that prenatal exposure to diazepam, phenobarbital, haloperidol and fluoxetine caused significantly enhanced aggression in terms of number of fighting bouts.     

Molecular differentiation of the mouse genital tract: altered protein synthesis following prenatal exposure to diethylstilbestrol

Exposure in utero to the synthetic estrogen diethylstilbestrol (DES) has been associated with the subsequent development of reproductive tract lesions in both women and experimental animals. Using the techniques of organ culture and two-dimensional (2-D) gel electrophoresis, the effects of DES on protein synthetic patterns were studied during fetal and neonatal development of the CD-1 mouse. The protein patterns, analyzed by comparing 2-D fluorograms after [35S] methionine incorporation at different developmental stages, were correlated with the histology at the same age. Several qualitative and quantitative changes in protein synthesis were observed after prenatal DES exposure. A protein, apparent by Day 14 of gestation, with molecular weight approximately 70,000 and pI of 5.8, was observed to be greatly diminished in all reproductive tract tissues exposed to DES during prenatal development. This alteration, induced in utero, persists through the early postnatal differentiation of the genital tract (17 days old). This protein may provide an early marker for alterations in normal reproductive tract function.     

Antagonism of the anticonvulsant action of phenytoin,phenobarbital and acetazolamide by 6-hydroxydopamine

The ability of phenytoin, phenobarbital and acetazolamide to prevent the tonic extensor component of the maximal electroshock seizure was evaluated 30–50 days after treatment with 6-hydroxydopamine (6-OHDA). In the case of all 3 drugs, protection of rats from tonic extension was markedly reduced in the catecholamine amine deficient animals. However, the 6-OHDA-induced antagonism of anticonvulsant action was in all cases surmountable by increasing the dose of the anticonvulsant. These findings suggest a nonspecific antagonism of anticonvulsant action in 6-OHDA treated rats probably resulting from the increase in seizure susceptibility associated with catecholamine depletion.     

Release of14C-adenine derivatives from cerebral cortical slices: Effect of phenytoin and phenobarbital

Both ouabain, 0.1 mM, and veratridine, 0.05 mM, increased the release of¹⁴C-labeled compounds from rat cortical slices prelabeled with¹⁴C-adenine and incubated in vitro. The increment in radioactivity released by both depolarizing agents was almost entirely a result of increases in adenosine, inosine, and hypoxanthine. However, the distribution of these three compounds in the ouabain-induced efflux (adenosine, 12%; inosine, 51%; hypoxanthine, 36%) contrasted with that evoked by veratridine (adenosine, 42%; inosine, 15%; hypoxanthine, 38%). Phenytoin significantly reduced the efflux of¹⁴C-labeled compounds produced by both ouabain and veratridine, but phenobarbital had no effect. The intracortical injection of adenosine, inosine, and hypoxanthine has been shown to induce epileptiform discharges in rats, and it is suggested that the inhibitory effect of phenytoin on the release of adenine derivatives may play a role in its antiepileptic action.     

Impact of prenatal diagnosis on livebirth prevalence of children with congenital anomalies

The objectives of this study were to describe the impact of prenatal diagnosis on the birth prevalence of congenital anomalies over 21 years (1979-1999) in a well defined population in northeastern France (13,500 births per year). The material for this study came from the analysis of data from multiple sources on births and terminations of pregnancy after prenatal diagnosis of congenital anomalies in 279,642 consecutive pregnancies of known outcome. The study period was divided into three subgroups 1979-1988, 1989-1993 and 1994-1999. Between 1979-1988, 1989-1993 and 1994-1999, prenatal detection of congenital anomalies increased, respectively, from 12.0% to 25.5% and to 31.7%. Termination of pregnancy (TOP) increased in the same proportions during the three time periods. However, the increase of TOP was much higher for chromosomal anomalies than for nonchromosomal congenital anomalies. The birth prevalence of Down's syndrome fell by 80% from 1979-1988 to 1994-1999. Sensitivity of prenatal detection of congenital anomalies and TOPs were lower for isolated cases (only one malformation present in the fetus) than for multiple malformations in the same fetus. Sensitivity varied with the type of malformations: it was high for neural tube defect (79.7%) and urinary anomalies (50.7%) and low for congenital heart defects (16.4%). In conclusion, the introduction of routine prenatal diagnosis has resulted in a significant fall in the birth prevalence of children with congenital anomalies. However, this fall varied with the types of congenital anomalies.     

Association of pigmentary anomalies with chromosomal and genetic mosaicism and chimerism.

We have evaluated eight patients with pigmentary anomalies reminiscent of incontinentia pigmenti or hypomelanosis of Ito. All demonstrated abnormal lymphocyte karyotypes with chromosomal mosaicism in lymphocytes and/or skin fibroblasts. In seven the skin was darkly pigmented, and in all of these seven cases the abnormal pigmentation followed Blaschko lines. The literature contains at least 36 similar examples of an association between pigmentary anomalies and chromosomal mosaicism, as well as five examples of an association with chimerism. The pigmentary anomalies are pleomorphic, and the chromosomal anomalies involve autosomes and sex chromosomes. The pigmentation patterns are reminiscent of the archetypal paradigm seen in allophenic mice and demonstrate the clonal origin of melanoblasts from neural crest precursors. Patients with anomalous skin pigmentation, particularly when it follows a pattern of Blaschko lines, should be appropriately evaluated for a possible association with chromosomal or genetic mosaicism or chimerism.     

In vitro concentration dependent transport of phenytoin and phenobarbital,but not ethosuximide,by human P-glycoprotein

AimsOne possible mechanism for epilepsy drug resistance is overexpression of P-glycoprotein in the blood–brain barrier, but whether (or which) antiepileptic drugs (AEDs) are transported by P-gp remains unclear. We evaluated AEDs as P-gp substrates using cell monolayers.Main methodsBi-directional transport assays and concentration equilibrium transport assays (CETAs) were performed for phenytoin (PHT), phenobarbital (PB), and ethosuximide (ESM) using wildtype Madin–Darby Canine Kidney II cell line MDCKII and porcine renal endothelial cell line LLC–PK1 cells and these cells transfected with human MDR1 cDNA to express P-gp.Key findingsWildtype cells demonstrated no efflux transport of PHT, PB, or ESM. In CETAs, both MDR1-transfected cell lines transported PHT from basolateral to apical when PHT loading concentrations were 5 or 10, but not 20 µg/ml. MDCK–MDR1 cells transported PB when initial concentrations were 10 or 20, but not 5 µg/ml. LLC–MDR1 did not transport PB. P-gp inhibitor verapamil blocked efflux transport. MDR1-transfected cells did not transport ESM at 5.6 or 56 µg/ml. Bi-directional transport assays demonstrated weak transport for PHT but not PB or ESM.SignificanceHuman P-gp transports PHT and PB, but not ESM, in a concentration dependent manner. CETA may be more sensitive than bi-directional assays to detect transport of drugs with high passive diffusion. Potential P-gp substrates should be tested at clinically relevant concentration ranges.     

Adverse effects of prenatal methimazole exposure.

BACKGROUND: A specific phenotype of methimazole (MMI) induced malformations has recently been postulated. MMI embryopathy is characterized by minor dysmorphic features, choanal atresia and/or esophageal atresia, growth retardation, and developmental delay. METHODS: We prospectively studied the outcome of pregnancy in 241 women counseled by 10 Teratology Information Services (TIS) of the European Network of Teratology Information Services (ENTIS) because of MMI exposure, and compared them with those of 1,089 pregnant women referred to TIS because of exposure to nonteratogenic drugs (control group). Information was obtained by mail or telephone interview. RESULTS: There was no increase in the general rate of major anomalies or of spontaneous or induced abortions in the MMI-exposed group in comparison with the control group. Two newborns were affected with one of the major malformations that are part of the postulated embryopathy. CONCLUSIONS: The results of this study indicate that choanal as well as esophageal atresia may have a higher incidence than expected in fetuses exposed to MMI between 3 and 7 gestational weeks. Until further data are available, thyrotoxicosis should be treated with propylthiouracil, as it is apparently safer for use during the fertile period.     

Neuroimaging of children following prenatal drug exposure

Recent advances in MR-based brain imaging methods have provided unprecedented capabilities to visualize the brain. Application of these methods has allowed identification of brain structures and patterns of functional activation altered in offspring of mothers who used licit (e.g., alcohol and tobacco) and illicit (e.g., cocaine, methamphetamine, and marijuana) drugs during pregnancy. Here we review that literature, which though somewhat limited by the complexities of separating the specific effects of each drug from other confounding variables, points to sets of interconnected brain structures as being altered following prenatal exposure to drugs of abuse. In particular, dopamine-rich cortical (e.g., frontal cortex) and subcortical (e.g., basal ganglia) fetal brain structures show evidence of vulnerability to intrauterine drug exposure suggesting that during brain development drugs of abuse share a specific profile of developmental neurotoxicity. Such brain malformations may shed light on mechanisms underlying prenatal drug-induced brain injury, may serve as bio-markers of significant intrauterine drug exposure, and may additionally be predictors of subsequent neuro-developmental compromise. Wider clinical use of these research-based non-invasive methods will allow for improved diagnosis and allocation of therapeutic resources for affected infants, children, and young adults.