Role of Cbp, p300 and Akt in valproic acid induced neural tube defects in CD-1 mouse embryos.

Valproic acid (VPA), an antiepileptic and mood-stabilizing drug, is prescribed to women of reproductive age. VPA is associated with a 1-2% increase in neural tube defects in offspring following gestational exposure and results in epigenetic modifications induced by perturbations in transcription cofactors. Cbp and p300, two transcription cofactors, play key roles in embryonic neural development. p300 is a downstream target of Akt, a protein kinase B associated with cell survival and anti-apoptotic mechanisms, as part of the Akt-p300 axis. We examined the effects of in utero VPA exposure on Cbp, p300, and Akt in gestational day (GD)9, GD10 and GD13 CD-1 mouse embryos following a teratogenic maternal dose of 400 mg/kg. Embryos were collected at 0, 1, 3 and 6 h post-dosing on GD9, 24 h post-dosing on GD10 and on GD13. GD10 embryos were grouped according to the status of neural tube closure in control, closed and open groups. GD13 heads were grouped as control, exposed but non-exencephalic and exencephalic. Our data indicate that Cbp, p300 and Akt mRNA levels were downregulated at 1 and 3 h post-exposure in GD9 embryos while Cbp and p300 protein levels remained stable. Akt protein levels were significantly increased 1 h post-exposure. No significant changes were observed in either mRNA or protein expression in embryos with closed or open neural tubes compared to the control group at GD10. Downregulated expression of Cbp, p300, and Akt may play a key role in VPA-induced neural tube defects considering their vitally important role in embryonic development.

Noncoding RNAs in development and teratology, with focus on effects of cannabis, cocaine, nicotine, and ethanol.

Completion of the Human Genome Project has led to the identification of a large number of transcription start sites that are not paired with protein-coding genes, supporting the growing recognition of the abundance of encoded nonprotein-coding RNAs (ncRNAs) and their importance for speciation and species-specific development. Present in both plants and animals, ncRNAs vary in size, function, primary sequence, and secondary structure. While microRNAs (miRNAs) are the best known, there are a number of other ncRNAs (long[er] nonprotein-coding RNA, pseudogenes, circular RNAs, and so on) that have been shown to play an important role in the development either directly or via networks of proteins and other ncRNAs, including modulating the impact of miRNAs. Furthermore, these ncRNAs and their developmental regulatory networks are sensitive to teratogens such as ethanol, cannabis, cocaine, and nicotine. A better understanding of the developmental role of ncRNAs and their capacity to mediate teratogenesis is a necessary step in efforts to minimize the long-term consequences of developmental exposures to drugs-of-abuse. Moreover, with increasing awareness of the prevalence of polydrug use, experimental models will need to incorporate more complex drug exposure paradigms into meaningful assessments of developmental ncRNA function.

Hydroxyurea embryotoxicity is enhanced in P53-deficient mice.

Hydroxyurea, a ribonucleotide reductase inhibitor, is a potent teratogen in mice, causing severe limb and skeletal defects. The exposure of gestation day nine murine embryos to hydroxyurea elicits an early embryonic stress response that involves activation of the P53 transcription factor. The impact of this P53 activation on the embryotoxicity of hydroxyurea- is not known. The goal of this study was to test the hypothesis that P53 acts to suppress hydroxyurea embryotoxicity. Trp53+/- timed pregnant mice were treated with saline or hydroxyurea (200 or 400 mg/kg) on gestation day nine; fetuses were examined for viability and external and skeletal malformations on gestation day eighteen. Neither the deletion of Trp53 nor hydroxyurea treatment significantly affected fetal growth although a trend towards a decrease in fetal weights was observed in Trp53-/- fetuses. However, hydroxyurea induced a significantly higher incidence of malformations and resorptions in Trp53-/- fetuses compared to their wildtype littermates. Thus, fetal P53 genotype is an important determinant of the effects of hydroxyurea on organogenesis-stage embryos.

Importance of a multidisciplinary approach and monitoring in fetal warfarin syndrome.

Warfarin is a synthetic oral anticoagulant that crosses the placenta and can lead to a number of congenital abnormalities known as fetal warfarin syndrome. Our aim is to report on the follow-up from birth to age 8 years of a patient with fetal warfarin syndrome. He presented significant respiratory dysfunction, as well as dental and speech and language complications. The patient was the second child of a mother who took warfarin during pregnancy due to a metallic heart valve. The patient had respiratory dysfunction at birth. On physical examination, he had a hypoplastic nose, pectus excavatum, and clubbing of the fingers. Nasal fibrobronchoscopy showed upper airway obstruction due to narrowing of the nasal cavities. He underwent surgical correction with Max Pereira graft, zetaplasty, and osteotomies for the piriform aperture. At dental evaluation, he had caries and delayed eruption of the upper incisors. Speech and language assessment revealed high palate, mouth breathing, little nasal patency, and shortened upper lip. Auditory long latency and cognitive-related potential to auditory stimuli demonstrated functional changes in the cortical auditory pathways. We believe that the frequency of certain findings observed in our patient may be higher in fetal warfarin syndrome than is appreciated, since a significant number result in abortions, stillbirths, or children evaluated in the first year of life without a follow-up. Thus, a multidisciplinary approach and long-term monitoring of these patients may be necessary.

Role of mutation and pharmacologic block of human KCNH2 in vasculogenesis and fetal mortality: partial rescue by transforming growth factor-ß.

BACKGROUND: N629D KCNH2 is a human missense long-QT2 mutation. Previously, we reported that the N629D/N629D mutation embryos disrupted cardiac looping, right ventricle development, and ablated IKr activity at E9.5. The present study evaluates the role of KCNH2 in vasculogenesis. METHODS AND RESULTS: N629D/N629D yolk sac vessels and aorta consist of sinusoids without normal arborization. Isolated E9.5 +/+ first branchial arches showed normal outgrowth of mouse ERG-positive/α-smooth muscle actin coimmunolocalized cells; however, outgrowth was grossly reduced in N629D/N629D. N629D/N629D aortas showed fewer α-smooth muscle actin positive cells that were not coimmunolocalized with mouse ERG cells. Transforming growth factor-ß treatment of isolated N629D/N629D embryoid bodies partially rescued this phenotype. Cultured N629D/N629D embryos recapitulate the same cardiovascular phenotypes as seen in vivo. Transforming growth factor-ß treatment significantly rescued these embryonic phenotypes. Both in vivo and in vitro, dofetilide treatment, over a narrow window of time, entirely recapitulated the N629D/N629D fetal phenotypes. Exogenous transforming growth factor-ß treatment also rescued the dofetilide-induced phenotype toward normal. CONCLUSIONS: Loss of function of KCNH2 mutations results in defects in cardiogenesis and vasculogenesis. Because many medications inadvertently block the KCNH2 potassium current, these novel findings seem to have clinical relevance.

In silico screening of the impact of hERG channel kinetic abnormalities on channel block and susceptibility to acquired long QT syndrome.

Accurate diagnosis of predisposition to long QT syndrome is crucial for reducing the risk of cardiac arrhythmias. In recent years, drug-induced provocative tests have proved useful to unmask some latent mutations linked to cardiac arrhythmias. In this study we expanded this concept by developing a prototype for a computational provocative screening test to reveal genetic predisposition to acquired long-QT syndrome (aLQTS). We developed a computational approach to reveal the pharmacological properties of I(Kr) blocking drugs that are most likely to cause aLQTS in the setting of subtle alterations in I(Kr) channel gating that would be expected to result from benign genetic variants.Weused themodel to predict themost potentially lethal combinations of kinetic anomalies and drug properties. In doing so, we also implicitly predicted ideal inverse therapeutic properties of K channel openers that would be expected to remedy a specific defect. We systematically performed "in silico mutagenesis" by altering discrete kinetic transition rates of the Fink et al. Markov model of human I(Kr) channels, corresponding to activation, inactivation, deactivation and recovery from inactivation of I(Kr) channels. We then screened and identified the properties of I(Kr) blockers that caused acquired long QT and therefore unmasked mutant phenotypes formild,moderate and severe variants. Mutant I(Kr) channels were incorporated into the O'Hara et al. human ventricular action potential (AP) model and subjected to simulated application of a wide variety of I(Kr)-drug interactions in order to identify the characteristics that selectively exacerbate the AP duration (APD) differences between wild-type and I(Kr) mutated cells. Our results show that drugs with disparate affinities to conformation states of the I(Kr) channel are key to amplify variants underlying susceptibility to acquired long QT syndrome, an effect that is especially pronounced at slow frequencies. Finally, we developed a mathematical formulation of the M54T MiRP1 latent mutation and simulated a provocative test. In this setting, application of dofetilide dramatically amplified the predicted QT interval duration in the M54T hMiRP1 mutation compared to wild-type.

Cadmium-induced embryopathy: nitric oxide rescues teratogenic effects of cadmium.

Although Cadmium (Cd) is a well-known heavy metal pollutant and teratogen, the mechanism behind Cd-mediated teratogenicity remains unknown. Previously, we have reported of the protective role of Nitric oxide (NO), a key signaling molecule in the embryonic developmental process, against Thalidomide-induced teratogenicity. The objective of this study was to obtain a mechanistic in-sight of the antiteratogenic potential of NO against Cd-mediated teratogenicity. To achieve this goal, we first studied the effect of Cd on the vasculature of developing embryos and then we investigated whether Cd mediated its effects by interfering with the redox regulation of NO signaling in the early development milieu. We used a chick embryonic model to determine the time and dose-dependent effects of Cd and NO recovery against Cd assault. The effects of Cd and NO recovery were assessed using various angiogenic assays. Redox and NO levels were also measured. Results demonstrated that exposure to Cd at early stage of development caused multiple birth defects in the chick embryos. Exposure to Cd suppressed endogenous NO levels and cGMP signaling, inhibiting angioblast activation and subsequently impairing yolk sac vascular development. Furthermore, Cd-induced superoxide and lipid peroxidation mediated activation of proapoptotic markers p21 and p53 in the developing embryo. Cd also caused the down-regulation of FOXO1, and up-regulation of FOXO3a and Caspase 3-mediated apoptosis. Addition of exogenous NO through a NO donor was able to blunt Cd-mediated effects and restore normal vascular and embryonic development. In conclusion, Cd-mediated teratogenicity occurs as a result of impaired NO-cGMP signaling, increased oxidative stress, and the activation of apoptotic pathways. Subsequent addition of exogenous NO through NO donor negated Cd-mediated effects and protected the developing embryo.

Pharmacogenetics of drug-induced birth defects: the role of polymorphisms of placental transporter proteins.

One of the ongoing issues in perinatal medicine is the risk of birth defects associated with maternal drug use. The teratogenic effect of a drug depends, apart from other factors, on the exposition of the fetus to the drug. Transporter proteins are known to be involved in the pharmacokinetics of drugs and have an effect on drug level and fetal drug exposure. This condition may subsequently alter the risk of teratogenicity, which occurs in a dose-dependent manner. This review focuses on the clinically important polymorphisms of transporter proteins and their effects on the mRNA and protein expression in placental tissue. We also propose a novel approach on how the different genotypes of the polymorphism can be translated into phenotypes to facilitate genetic association studies. The last section looks into the recent studies exploring the association between P-glycoprotein polymorphisms and the risk of fetal birth defects associated with medication use during pregnancy.

Epigenetic changes and disturbed neural development in a human embryonic stem cell-based model relating to the fetal valproate syndrome.

Exposure to the antiepileptic drug valproic acid (VPA) during gestation causes neurofunctional and anatomic deficits in later life. At present, there are little human data on how early neural development is affected by chemicals. We used human embryonic stem cells, differentiating to neuroectodermal precursors, as a model to investigate the modes of action of VPA. Microarray expression profiling, qPCR of specific marker genes, immunostaining and the expression of green fluorescent protein under the control of the promoter of the canonical neural precursor cell marker HES5 were used as readouts. Exposure to VPA resulted in distorted marker gene expression, characterized by a relative increase in NANOG and OCT4 and a reduction in PAX6. A similar response pattern was observed with trichostatin A, a potent and specific histone deacetylase inhibitor (HDACi), but not with several other toxicants. Differentiation markers were disturbed by prolonged, but not by acute treatment with HDACi, and the strongest disturbance of differentiation was observed by toxicant exposure during early neural fate decision. The increased acetylation of histones observed in the presence of HDACi may explain the up-regulation of some genes. However, to understand the down-regulation of PAX6 and the overall complex transcript changes, we examined further epigenetic markers. Alterations in the methylation of lysines 4 and 27 of histone H3 were detected in the promoter region of PAX6 and OCT4. The changes in these activating and silencing histone marks provide a more general mechanistic rational for the regulation of developmentally important genes at non-cytotoxic drug concentrations.

Potential relation of aberrant proteolysis of human protein tyrosine kinase 7 (PTK7) chuzhoi by membrane type 1 matrix metalloproteinase (MT1-MMP) to congenital defects.

Membrane PTK7 pseudo-kinase plays an essential role in planar cell polarity and the non-canonical Wnt pathway in vertebrates. Recently, a new N-ethyl-N-nitrosourea-induced mutant named chuzhoi (chz) was isolated in mice. chz embryos have severe birth defects, including a defective neural tube, defective heart and lung development, and a shortened anterior-posterior body axis. The chz mutation was mapped to the Ala-Asn-Pro tripeptide insertion into the junction region between the fifth and the sixth Ig-like domains of PTK7. Unexpectedly, chz reduced membrane localization of the PTK7 protein. We hypothesized and then proved that the chz mutation caused an insertion of an additional membrane type 1 matrix metalloproteinase cleavage site in PTK7 and that the resulting aberrant proteolysis of chz affected the migratory parameters of the cells. It is likely that aberrations in the membrane type 1 matrix metalloproteinase/PTK7 axis are detrimental to cell movements that shape the body plan and that chz represents a novel model system for increasing our understanding of the role of proteolysis in developmental pathologies, including congenital defects.

Short-time gene expression response to valproic acid and valproic acid analogs in mouse embryonic stem cells.

Prediction of developmental toxicity in vitro could be based on short-time toxicogenomic endpoints in embryo-derived cell lines. Microarray studies in P19 mouse embryocarcinoma cells and mouse embryos have indicated that valproic acid (VPA), an inducer of neural tube defects, deregulates the expression of many genes, including those critically involved in neural tube development. In this study, we exposed undifferentiated R1 mouse embryonic stem cells to VPA and VPA analogs for 6 h and used CodeLink whole-genome expression microarrays to define VPA-responsive genes correlating with teratogenicity. Compared with the nonteratogenic analog 2-ethyl-4-methylpentanoic acid, VPA and the teratogenic VPA analog (S)-2-pentyl-4-pentynoic acid deregulated a much larger number of genes. Five genes (of ∼2500 array probes correlating with the separation) were sufficient to effectively separate teratogens from nonteratogens. A large fraction of the target genes correlating with teratogenicity are functionally related to embryonic development and morphogenesis, including neural tube formation and closure. Similar responses in R1 were found for most genes previously identified as VPA responsive in P19 and embryos. A subset of target genes was evaluated as candidate markers predictive of potential teratogenicity against a range of known teratogens using TaqMan expression arrays. These marker genes showed a positive predictive value for the teratogens butyrate and trichostatin A, which like VPA and (S)-2-pentyl-4-pentynoic acid are known histone deacetylase (HDAC) inhibitors but not for compounds that are likely to act by other mechanisms. This indicates that HDAC inhibition may be a major mechanism by which VPA induces gene deregulation and possibly teratogenicity.

MicroRNA expression changes during zebrafish development induced by perfluorooctane sulfonate.

Perfluorooctane sulfonate (PFOS), a kind of widely distributed environmentally organic compound, has been found to cause developmental toxicity. Although microRNAs (miRNAs) play an important role in many metabolic tasks, whether and how they are involved in the process of PFOS-induced toxicity is largely unknown. To address this problem, PFOS-induced changes in miRNAs and target gene expression in zebrafish embryos, and the potential mechanism of PFOS-induced toxic action were studied in this research. Zebrafish embryos were exposed to 1 µg ml(-1) PFOS or DMSO control from 6 h post-fertilization (hpf) to 24 or 120 hpf. Subsequently, RNA was isolated from the embryo pool and the expression profiles of 219 known zebrafish miRNAs were analyzed using microarray. Finally, quantitative real-time polymerase chain reaction was used to validate several miRNAs expression of microarray data. The analysis revealed that PFOS exposure induced significant changes in miRNA expression profiles. A total of 39 and 81 miRNAs showed significantly altered expression patterns after PFOS exposure 24 and 120 hpf. Of the changed miRNAs, 20 were significantly up-regulated and 19 were significantly down-regulated (p < 0.01) at 24 hpf, whereas 41 were significantly up-regulated and 40 were significantly down-regulated (p < 0.01) at 120 hpf. These miRNAs were involved in development, apoptosis and cell signal pathway, cell cycle progression and proliferation, oncogenesis, adipose metabolism and hormone secretion, whereas there is still little functional information available for 32 miRNAs. Our results demonstrate that PFOS exposure alters the expression of a suite of miRNAs and may induce developmental toxicity.

Epigenetic modifications in valproic acid-induced teratogenesis.

Exposure to the anticonvulsant drug valproic acid (VPA) in utero is associated with a 1-2% increase in neural tube defects (NTDs), however the molecular mechanisms by which VPA induces teratogenesis are unknown. Previous studies demonstrated that VPA, a direct inhibitor of histone deacetylase, can induce histone hyperacetylation and other epigenetic changes such as histone methylation and DNA demethylation. The objective of this study was to determine if maternal exposure to VPA in mice has the ability to cause these epigenetic alterations in the embryo and thus contribute to its mechanism of teratogenesis. Pregnant CD-1 mice (GD 9.0) were administered a teratogenic dose of VPA (400mg/kg, s.c.) and embryos extracted 1, 3, 6, and 24h after injection. To assess embryonic histone acetylation and histone methylation, Western blotting was performed on whole embryo homogenates, as well as immunohistochemical staining on embryonic sections. To measure DNA methylation changes, the cytosine extension assay was performed. Results demonstrated that a significant increase in histone acetylation that peaked 3h after VPA exposure was accompanied by an increase in histone methylation at histone H3 lysine 4 (H3K4) and a decrease in histone methylation at histone H3 lysine 9 (H3K9). Immunohistochemical staining revealed increased histone acetylation in the neuroepithelium, heart, and somites. A decrease in methylated histone H3K9 staining was observed in the neuroepithelium and somites, METHYLATED histone H3K4 staining was observed in the neuroepithelium. No significant differences in global or CpG island DNA methylation were observed in embryo homogenates. These results support the possibility that epigenetic modifications caused by VPA during early mouse organogenesis results in congenital malformations.

Sensitivity to cadmium-chloride-induced forelimb ectrodactyly is independent of the p53 gene-dosage in the C57BL/6J mouse.

BACKGROUND: The p53 pathway plays an important role in the regulation of apoptosis, osteoblast differentiation, skeletal development, and teratogenic sensitivity. The administration of cadmium chloride (CdCl(2)) on gestational day 9 in susceptible mouse strains causes postaxial forelimb ectrodactyly in a percentage of fetuses through unknown mechanisms. In this study, the hypothesis that the p53 gene dosage might affect the incidence or severity of CdCl(2)-induced forelimb ectrodactyly was examined. METHODS: Heterozygous p53-null female mice, on the C57BL/6J background known to be sensitive to CdCl(2)-induced forelimb ectrodactyly, were mated with heterozygous males and then treated with a single intraperitoneal (ip) dose of CdCl(2) (4 mg x kg(-1)) at embryonic day (ED) 9. Embryos and fetuses, genotyped using DNA isolated from the yolk sacs, were collected at ED10 and examined for the pattern of cell death in the limb buds or collected at ED18 and examined for limb malformations. RESULTS: In the wild type and heterozygous p53 embryonic limb buds, CdCl(2)-induced apoptosis involved mesenchymal cells as well as the apical ectodermal ridge (AER), whereas CdCl(2)-induced apoptosis was restricted mainly to the AER in the homozygous p53-null limb buds. No difference in the incidence or severity of forelimb ectrodactyly in the embryos of different p53 genotypes was observed. CONCLUSION: Despite the fact that CdCl(2) induced both p53-dependent (in the mesenchyme) and p53-independent (in the AER) cell death in the developing limb bud, CdCl(2)-induced ectrodactyly was independent of the p53 gene dosage at the studied time point.

Prenatal exposure to environmental tobacco smoke alters gene expression in the developing murine hippocampus.

BACKGROUND: Little is known about the effects of passive smoke exposures on the developing brain. OBJECTIVE: The purpose of the current study was to identify changes in gene expression in the murine hippocampus as a consequence of in utero exposure to sidestream cigarette smoke (an experimental equivalent of environmental tobacco smoke (ETS)) at exposure levels that do not result in fetal growth inhibition. METHODS: A whole body smoke inhalation exposure system was utilized to deliver ETS to pregnant C57BL/6J mice for 6 h/day from gestational days 6-17 (gd 6-17) [for microarray] or gd 6-18.5 [for fetal phenotyping]. RESULTS: There were no significant effects of ETS exposure on fetal phenotype. However, 61 "expressed" genes in the gd 18.5 fetal hippocampus were differentially regulated (up- or down-regulated by 1.5-fold or greater) by maternal exposure to ETS. Of these 61 genes, 25 genes were upregulated while 36 genes were down-regulated. A systems biology approach, including computational methodologies, identified cellular response pathways, and biological themes, underlying altered fetal programming of the embryonic hippocampus by in utero cigarette smoke exposure. CONCLUSIONS: Results from the present study suggest that even in the absence of effects on fetal growth, prenatal smoke exposure can alter gene expression during the "early" period of hippocampal growth and may result in abnormal hippocampal morphology, connectivity, and function.

Reconstrução nasal neonatal na Síndrome do Warfarin Fetal / Neonatal nasal reconstruction in Fetal Warfarin Syndrome

O objetivo deste trabalho é relatar um caso de reconstrução nasal precoce em um paciente com síndrome do Warfarin fetal, onde um paciente de 23 dias com apresentava hipoplasia nasal isolada. O ganho ponderal estava estagnado e não havia possibilidade de introdução de sonda nasoentérica devido à deformidade. Foi realizada rinoplastia aberta com incisão transcolumelar. Dois enxertos de cartilagem tragal foram confeccionados e introduzidos na região da ponta, porção cranial do septo cartilaginoso e alares. O paciente apresentou melhoria da permeabilidade ventilatória, diminuição do ruído inspiratório, ganho de peso e também da forma. Após um ano de seguimento o resultado continuava satisfatório. Concluímos que a intervenção precoce é satisfatória e pode minimizar ou mesmo prevenir procedimentos futuros.

The aim of this work is to report a case of early nasal reconstruction in a 23-day-old patient with fetal Warfarin syndrome and isolated nasal hypoplasia. Weight gain was arrested and the deformity precluded the use of a nasogastric tube. An open rhinoplasty with transcolumellar incision was performed. Two grafts of tragal cartilage were made and introduced in the tip area, cranial portion of the cartilaginous septum, and alar cartilages. The patient presented improved ventilatory permeability, decrease of inspiratory noise, and weight and shape gains. At the one-year follow-up the result was still satisfactory. We concluded that early intervention is satisfactory and may minimize or even prevent future procedures.

6-mercaptopurine (6-MP) induces p53-mediated apoptosis of neural progenitor cells in the developing fetal rodent brain.

6-mercaptopurine (6-MP), a DNA-damaging agent, induces apoptosis of neural progenitor cells, and causes malformation in the fetal brain. The aim of the present study is to clarify the molecular pathway of 6-MP-induced apoptosis of neural progenitor cells in the fetal telencephalon of rats and mice. p53 protein is activated by DNA damage and induces apoptosis through either the intrinsic pathway involving the mitochondria or the extrinsic pathway triggered by death receptors. In this study, the expression of puma and cleaved caspase-9 proteins, which are specific intrinsic pathway factors, increased in the rat telencephalon after 6-MP treatment. 6-MP-induced apoptosis of neural progenitor cells was completely absent in p53-deficient mice. On the other hand, the expression of Fas protein, an extrinsic pathway factor, did not change throughout the experimental period in the rat telencephalon treated with 6-MP. The number of apoptotic neural progenitor cells was similar among Fas-mutated lpr/lpr and wild-type mice, suggesting that the Fas pathway does not play a significant role in 6-MP-induced apoptosis of neural progenitor cells. These results may suggest that the p53-mediated intrinsic pathway is essential for 6-MP-induced apoptosis of neural progenitor cells in the developing telencephalon of rats and mice.

Effects of the polysaccharide beta-glucan on clastogenicity and teratogenicity caused by acute exposure to cyclophosphamide in mice.

Alterations that could lead to the cancer development may also be related to an adverse development of offspring in experimental animals. Some functional foods, which contain the polysaccharide beta-glucan, have been described as being effective in the prevention of clastogenic damage. Based on that finding, the aim of the present study was to determine the efficacy of this sugar polymer in the mutagenic and teratogenic damage control. Two sets of females, pregnant and non-pregnant, were evaluated. The results indicated that beta-glucan was effective in preventing clastogenic damage in pregnant as well as non-pregnant females. In addition, pregnant females were more susceptible to mutagenic damage. However, teratogenic effects were not prevented effectively, although there was a trend toward a reduction in level of malformations. Despite beta-glucan did not prevent malformations, it increased fetal viability and reduced number of post-implantation losses and resorption, thereby enhancing reproductive performance in females.

Therapy-related patterns of cytogenetic abnormalities in acute myeloid leukemia and myelodysplastic syndrome post polycythemia vera: single center experience and review of literature.

A minor fraction of patients with polycythemia vera (PV) develop a terminal acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Analysis of the cytogenetic abnormalities during AML or MDS may help in understanding if this development is part of the natural course of the disease or induced by myelosuppressive therapy. Thirty-six cases with AML or MDS post PV, collected in a single Swedish institution during a 33-year period, are described with special regard to time to development of AML or MDS, therapy given during active PV, and cytogenetic findings during AML or MDS. A further 118 cases of AML or MDS post PV, in whom type of therapy during active PV and cytogenetic findings during AML or MDS were reported, were collected from the literature. AML or MDS developed in our own series after 1-30 years with a fairly constant rate (two cases per year). The most frequent cytogenetic abnormalities were +1q, -5, 5q-, -7, 7q-, +8, +9, 11q-, 13q-, and 20q-. When patients in the total material (n = 154) were divided with regard to treatment during active PV, marked differences were observed. The highest frequency of abnormalities was found in patients given multiple lines of therapy (n = 61), dominating features being -5/5q- in 28 patients (46%), -7/7q- in 19 patients (31%), numerous translocations in 24 patients (39%), and unidentified markers in 22 patients (36%). Half of the patients treated with hydroxyurea alone showed a -5 or 5q- abnormality. In patients treated with phlebotomy alone, +8 and +9 were the most frequent findings. The type of therapy given during active PV influences the type of chromosome abnormalities present during terminal AML or MDS and can also be instrumental in the development of leukemia.

Antiepileptic medication during pregnancy: does fetal genotype affect outcome?

Congenital abnormalities and impaired development in childhood are attributable to fetal exposure to antiepileptic drugs (AEDs). Pregnancy registries set up to obtain information about the potential risks of fetal exposure to AEDs, in particular major congenital malformations (MCMs), suggest that valproate exposure increases the frequency of congenital malformations more than other AEDs. Furthermore, follow-up studies have drawn attention to cognitive impairments in later childhood after prenatal exposure to valproate. Fetal exposure to AEDs may be influenced by drug transporting proteins in the placenta, including P-glycoprotein (P-gp), multidrug resistance protein (MRP) 1, and breast cancer resistance protein (BCRP). Their location in the syncytiotrophoblast plasma membrane, at the interface of the maternal and fetal circulations, allows these transport proteins to efflux xenobiotics back to the mother and offers the fetus protection from medications taken during pregnancy. Genetic variations in the expression and activity of these transport proteins may influence fetal exposure to AEDs and thus the risk of teratogenicity. Identification of a hierarchy of haplotypes ranging from susceptible to protective of congenital abnormalities could assist genetic counseling, in assessing fetal risks from exposure to AEDs.