Expression of Fibroblast Growth Factor 4 in a Rat Model of Polydactyly of the Thumb Induced by Cytarabine.

BACKGROUND The aim of this study was to assess the expression and mechanisms of fibroblast growth factor 4 in polydactyly of the thumb induced by cytarabine. MATERIAL AND METHODS Rats were intraperitoneally injected with cytarabine at different gestation periods (12.5 days, 13.5 days, and 14.5 days) to establish a polydactyly of the thumb model. Then, the expression of FGF4 in polydactyly was studied by whole-mount in situ hybridization. We used hematoxylin & eosin stain and cartilage stain to investigate the development of the skeleton and tissues in the embryo. Pictures were taken to determine the general shape of the deformity, then X-rays were taken to detect bone distortion of the rats born with a congenital malformation. RESULTS In the experimental group (11.5 days, 12.5 days, 13.5 days, and 14.5 days), whole-mount in situ hybridization showed that the FGF4 expression at the tip of the embryonic limb bud was significantly increased compared with the control group and FGF4 was distributed in a wider range and lasted longer than in the control group (P<0.01). HE staining and cartilage staining showed that there was an extra metacarpal bone and a phalanx in the rats with polydactyly of the thumb (P<0.01). Images of the deformed limbs showed polydactyly and syndactyly of the thumb in the rats. Further X-ray examination revealed 1 extra metacarpal bone and 1 extra phalanx. CONCLUSIONS Cytarabine can induce polydactyly and syndactyly of the thumb in rats. In this process, cytarabine can induce the expression of FGF4 on the tip of the embryonic limb bud, which further leads to abnormal development of the embryonic limb bud and eventually causes a congenital deformity.

Association between maternal exposure to PM10 and polydactyly and syndactyly: A population-based case-control study in Liaoning province, China.

BACKGROUND: The number of studies on air pollution with birth defects as the primary outcome has increased dramatically over the past two decades, but the potential role of specific air pollutants in congenital limb anomalies remains unclear. OBJECTIVES: To evaluate associations between preconception and first-trimester PM10 exposure and polydactyly and syndactyly in a population-based case-control study. METHODS: Polydactyly cases (n = 2605), syndactyly cases (n = 595), and controls without any birth defects (n = 7950) born between 2010 and 2015 were selected from the Maternal and Child Health Certificate Registry of Liaoning Province. The monthly mean PM10 concentrations were obtained from 75 air monitoring stations, and the exposure assessment was based on the mean concentration of all stations in mother's residential city. A multivariable logistic regression model was constructed to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: PM10 exposure was positively associated with the risks of polydactyly (preconception: aORT3 vs. T1 = 1.95, 95% CI 1.56-2.45, aOR = 1.06, 95% CI 1.01-1.10 [per 10-µg/m3 increment]; first-trimester: aORT3 vs. T1 = 2.51, 95% CI 2.00-3.15) and syndactyly (preconception: aORT3 vs. T1 = 2.86, 95% CI 1.98-4.13, aOR = 1.11, 95% CI 1.03-1.20 [per 10-µg/m3 increment]; first-trimester: aORT3 vs. T1 = 3.10, 95% CI 2.11-4.56). Analyses based on single month exposure windows basically showed similar positive associations. Additionally, these findings were robust in sensitivity analyses and broadly consistent across subgroups. CONCLUSION: Our study suggest that preconception and first-trimester PM10 exposures are related to increased risks of polydactyly and syndactyly.

Developmental toxicity of flucytosine following administration to pregnant rats at a specific time point of organogenesis.

To investigate the abnormalities that are specific to administration of flucytosine at one time point during embryonic organogenesis, flucytosine was administered orally to pregnant Sprague Dawley (SD) rats in a single dose on day 11 of pregnancy at 25 or 35 mg/kg. Fetuses on day 20 of pregnancy were externally, viscerally, and skeletally examined. Maternal body weight gain and food consumption were suppressed the day after administration of a 35 mg/kg. Fetal examinations revealed various alterations in both dose groups: externally preaxial polydactyly in the hind limb; skeletally fused lumbar centrum, absent sacral centrum, supernumerary sacral vertebra, and absent ribs. Our findings indicated that specific types of external and skeletal anomalies were induced following flucytosine administration on day 11 of pregnancy.

Recognition of the phenotype of thalidomide embryopathy in countries endemic for leprosy: new cases and review of the main dysmorphological findings.

Thalidomide is the best-known teratogen worldwide. It was first marketed as a sedative in the late 1950s, but the birth of ~10 000 children with birth defects resulted in the withdrawal of thalidomide from the market in 1962. Thalidomide embryopathy affects almost all organs but the main defects are concentrated in the limbs, eyes, ears, and heart. Shortly after the withdrawal of thalidomide from the market, its effectiveness in the treatment of erythema nodosum leprosum, an inflammatory condition resulting from leprosy, was reported and since the mid-1990s, the drug has been used widely in the treatment of cancers and autoimmune diseases, among other conditions. 40 000 new cases of leprosy are diagnosed every year in Brazil. Although there is a strict legislation for the prescription and use of thalidomide in Brazil, cases of thalidomide embryopathy have continued to be reported. Here, we present two new cases of thalidomide embryopathy identified in 2011 and review the major clinical findings in the literature that can aid the identification of the embryopathy.

Fibular dimelia and mirror polydactyly of the foot in a girl presenting additional features of the VACTERL association.

CONTEXT: The association between fibular dimelia and mirror polydactyly of the foot is considered to be a very rare lower-limb abnormality. On the other hand, VACTERL is an acronym for a nonrandom association of congenital anomalies for which the etiology is still poorly understood. CASE REPORT: The patient was a seven-month-old white girl whose mother had used misoprostol in the second month of pregnancy to induce abortion. On clinical evaluation, she was small for her age and presented hypotonia, anteverted nares, long philtrum and carp-like mouth. Her left hand had a reduction defect, with absence of the extremities of the second, third and fifth fingers and camptodactyly of the fourth finger. The ipsilateral lower limb presented significant shortening, especially rhizomelic shortening. Her left foot had a mirror configuration with seven toes and no identifiable hallux. The pelvis was hypoplastic. Esophageal atresia with tracheoesophageal fistula and imperforate anus were detected during the neonatal period. Abdominal ultrasound identified agenesis of the right kidney and left pyelocaliceal duplication. Radiographic evaluation on the left side showed iliac and femoral hypoplasia, absence of the tibia with a duplicated fibula and seven metatarsals and toes with no identifiable hallux on the foot. Echocardiography demonstrated an atrial septal defect. Based on the literature, we believe that the spectrum of malformations presented by our patient may be related to the vascular disruptive effect of the misoprostol. However, we cannot rule out the possibility that this association might simply be a coincidence.

Fibular dimelia and mirror polydactyly of the foot in a girl presenting additional features of the VACTERL association / Dimelia fibular e polidactilia em espelho do pé em uma menina apresentando achados adicionais de associação VACTERL

CONTEXT: The association between fibular dimelia and mirror polydactyly of the foot is considered to be a very rare lower-limb abnormality. On the other hand, VACTERL is an acronym for a nonrandom association of congenital anomalies for which the etiology is still poorly understood. CASE REPORT: The patient was a seven-month-old white girl whose mother had used misoprostol in the second month of pregnancy to induce abortion. On clinical evaluation, she was small for her age and presented hypotonia, anteverted nares, long philtrum and carp-like mouth. Her left hand had a reduction defect, with absence of the extremities of the second, third and fifth fingers and camptodactyly of the fourth finger. The ipsilateral lower limb presented significant shortening, especially rhizomelic shortening. Her left foot had a mirror configuration with seven toes and no identifiable hallux. The pelvis was hypoplastic. Esophageal atresia with tracheoesophageal fistula and imperforate anus were detected during the neonatal period. Abdominal ultrasound identified agenesis of the right kidney and left pyelocaliceal duplication. Radiographic evaluation on the left side showed iliac and femoral hypoplasia, absence of the tibia with a duplicated fibula and seven metatarsals and toes with no identifiable hallux on the foot. Echocardiography demonstrated an atrial septal defect. Based on the literature, we believe that the spectrum of malformations presented by our patient may be related to the vascular disruptive effect of the misoprostol. However, we cannot rule out the possibility that this association might simply be a coincidence.

CONTEXTO: A associação entre dimelia fibular e polidactilia em espelho do pé é considerada uma anormalidade de membro inferior bastante rara. Por outro lado, VACTERL é um acrônimo para uma associação não aleatória de anomalias congênitas cuja etiologia ainda é pouco compreendida. RELATO DO CASO: A paciente era uma menina branca de sete meses de idade, cuja mãe utilizou misoprostol no segundo mês de gravidez para indução de aborto. Na avaliação clínica, ela era pequena para a idade e apresentava hipotonia, narinas antevertidas, filtro longo e boca em carpa. A mão esquerda apresentava um defeito de redução com ausência das extremidades do segundo, terceiro e quinto dedos e camptodactilia do quarto. O membro inferior ipsilateral apresentava um importante encurtamento, especialmente rizomélico. O pé possuía uma configuração em espelho com sete dedos e nenhum hálux identificável. A pelve era hipoplásica. Atresia de esôfago com fístula traqueoesofágica e imperfuração anal foram detectadas durante o período neonatal. O ultrassom abdominal identificou agenesia do rim direito e duplicidade pielocalicial à esquerda. A avaliação radiográfica mostrou, no lado esquerdo, hipoplasia do osso ilíaco e do fêmur, ausência da tíbia com duplicação da fíbula, e presença de sete metatarsos e dedos, sem um hálux identificável, no pé. A ecocardiografia identificou um defeito do septo atrial. Acreditamos, com base na literatura, que o espectro de anormalidades apresentado por nossa paciente possa estar relacionado com o efeito disruptivo vascular do misoprostol. Entretanto, não podemos excluir a possibilidade de que essa associação possa ter sido simplesmente uma coincidência.

Busulfan-induced central polydactyly, syndactyly and cleft hand or foot: a common mechanism of disruption leads to divergent phenotypes.

The prevalence of clinical phenotypes that exhibit combinations of central polydactyly, syndactyly, or cleft hand or foot is higher than would be expected for random independent mutations. We have previously demonstrated that maternal ingestion of a chemotherapeutic agent, busulfan, at embryonic day 11 (E11) induces these defects in various combinations in rat embryo limbs. In an effort to determine the mechanism by which busulfan disrupts digital development, we examined cell death by Nile Blue staining and TdT-mediated dUTP nick end labeling (TUNEL) assays; we also carried out whole mount in situ hybridization for fibroblast growth factor-8 (Fgf8), bone morphogenetic protein-4 (Bmp4), and sonic hedgehog (Shh) to examine developmental pathways linked to these defects. In busulfan-treated embryos, diffuse cell death was evident in both ectoderm and mesoderm, peaking at E13. The increased cell death leads to regression of Fgf8 in the apical ectodermal ridge (AER) and Bmp4 and Shh in the underlying mesoderm. The subsequent pattern of interdigital apoptosis and cartilage condensation was variably disrupted. These results suggest that busulfan manifests its teratogenic effects by inducing cell death of both ectoderm and mesoderm, with an associated reduction in tissue and a disruption in the generation of patterning molecules during critical periods of digit specification.

Exencephaly induction by valproic acid in the genetic polydactyly/arhinencephaly mouse, Pdn/Pdn.

Non-treated homozygous polydactyly/arhinencephaly (Pdn/Pdn) mouse fetuses exhibited exencephaly in 16.7% of cases. Treatment of Pdn/Pdn mice with 350 mg/kg of valproic acid (VPA) on days 8.5 and 9.5 of gestation increased the rate of exencephaly to 66.7%. The responsible gene for the Pdn mouse phenotype has been determined to be Gli3, and the suppression of Gli3 gene expression has been documented in Pdn/Pdn embryos. We investigated how the sonic hedgehog (Shh) and Fgf8 genes, the correlated genes of Gli3, are expressed in the VPA-treated exencephalic Pdn/Pdn embryos on day 10 of gestation, using whole mount in situ hybridization (WISH) and real-time PCR methods. We could not detect any alterations in Shh expression by real-time PCR, or WISH in the non-treated Pdn/Pdn and VPA-treated exencephalic Pdn/Pdn embryos. Altered Fgf8 expression patterns were observed in the commissural plate and dorsal isthmal neuroepithelium in the non-treated Pdn/Pdn embryos. We speculated that the altered expression of Fgf8 might be the result of down-regulation of Gli3 in Pdn/Pdn embryos. Fgf8 gene expression in the commissural plate and dorsal isthmal neuroepithelium exhibits wide or altered signal patterns in the VPA-treated exencephalic Pdn/Pdn embryo. From these findings, it was suggested that down-regulation of Gli3 gene expression induced the altered expression of Fgf8 in the Pdn/Pdn embryos, and that VPA treatment accelerated the alterations of Fgf8 gene expression in the Pdn/Pdn embryos. It was further speculated that altered expression of Fgf8 in the commissural plate may be the fundamental cause of exencephaly, and that the synergistic effect between gene and drug shown in this experiment may explain the differences of sensitivity in the side-effects of the drug.

Teratogenicity and developmental toxicity of chlorpyrifos. Maternal exposure during organogenesis in mice.

Chlorpyrifos, an organophosphate pesticide, was evaluated for potential teratogenicity and developmental toxicity in mice. Pregnant females were given a single intraperitoneal injection (40 or 80 mg/kg) on day 10 of gestation and fetuses were evaluated on gestation day 17. At 80 mg/kg, chlorpyrifos treatment resulted in a significant reduction in numbers of live fetuses, and increase in resorptions, versus control litters. There was no indication of maternal toxicity. External and skeletal malformations were observed at 80 mg/kg, but not 40 mg/kg. Rates of fetuses with cleft palate increased significantly (p<0.05) following 80 mg/kg chlorpyrifos (5.97%) versus control litters (0.97%). Similarly, the absence of thoracic vertebrae was increased and the number of caudal vertebrae was significantly decreased. It is suggested that chlorpyrifos is teratogenic and embryotoxic in mice at doses below those that cause significant maternal toxicity.

The possible association between the combination of vaginal metronidazole and miconazole treatment and poly-syndactyly Population-based case-control teratologic study.

The objective of the study was to investigate the human teratogenic potential of vaginal metronidazole+miconazole treatment during pregnancy, because these antimicrobial drugs separately did not indicate human teratogenic potential in our and other studies. The analysis of cases with 21 groups of congenital abnormalities and their all matched controls was carried out in the population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996 including 38,151 pregnant women who had newborn infants without any congenital abnormalities (control group) and 22,843 pregnant women who had newborn infants or fetuses with congenital abnormalities. The prevalence of vaginal metronidazole+miconazole treatment during pregnancy was 2.5% (N=576) in the case group and 2.2% (N=846) in the control group [crude prevalence odds ratio (POR) with 95% confidence interval (CI): 1.2, 1.0-1.3]. The analysis of cases and their matched controls indicated an association between vaginal metronidazole+miconazole use and poly/syndactyly during the second through third months of gestation (adjusted POR 6.0, 95% CI 2.4-15.2). This finding may be connected with recall bias, although this bias was restricted by the evaluation of maternal drug use only during the critical period of poly/syndactyly and by evaluating only medically recorded metronidazole+miconazole treatment. The conclusion of the study is that this finding can be regarded as a signal for the possible association between vaginal treatment of metronidazole+miconazole during pregnancy and poly/syndactyly without any plausible biological hypothesis.

Teratogenic mechanisms of longitudinal deficiency and cleft hand.

In order to better understand the teratogenic mechanisms of congenital defects of the digits, we analyzed clinical cases and induced similar types of congenital hand anomalies in rat fetuses by oral administration of busulfan. In clinical cases, radial and ulnar deficiencies had common characteristic features. We induced radial and ulnar deficiencies in rat fetuses with the same drug. Radial and ulnar deficiencies induced in rats have similar clinical manifestations and these anomalies might be caused by the same teratogenic mechanism. Then, the formation of the digital rays was examined histologically. The results of histological examination suggested that these deficiencies were not caused by localized damage of the limb bud. They also suggested that the cause of missing digits in longitudinal deficiency is closely related to a deficit of mesenchymal cells in the limb bud. Cleft hand is considered to be one of the types of longitudinal deficiency. However, several investigators have suggested that the abnormal induction of finger rays in the process of formation of fingers induced central polydactyly, osseous syndactyly and also cleft hand. X-rays of the clinical cases and skeletal changes of the anomalies induced in rats appear to demonstrate that cleft hand formation proceeds from osseous syndactyly and central polydactyly. The results of our experimental study show that the critical periods of central polydactyly, osseous syndactyly and cleft hand are the same. They also suggest that central polydactyly, syndactyly and cleft hand might be induced when the same teratogenic factor acts on embryos at the same developmental stage in the human being. Because they have a similar causation, cleft hand, syndactyly and central polydactyly should be classified into the same entity, that is, abnormal induction of digital rays. Based on these clinical and experimental studies, we modified the Swanson classification. In our modified classification, typical cleft hand, syndactyly and polydactyly are included in the same category of abnormal induction of digital rays as the fourth new category.

Alteration of programmed cell death and gene expression by 5-bromodeoxyuridine during limb development in mice.

Some chemicals are known to induce limb malformations in mice. The occurrence of limb abnormality induced by chemical reagents is due to changes in the programmed cell death (PCD). 5-Bromodeoxyuridine (BrdU) is known as a potent teratogen and has been reported to induce polydactyly and other limb malformations in rodents (DiPaolo, Science 145, 501-503, 1964). Here, we undertook the morphological and genetic analyses of fetuses with limb malformations in BrdU-treated mice, in order to investigate an alteration of gene expression that resembles that of mutant mice with similar limb malformations. The fetuses of the BrdU-treated mice exhibited preaxial polydactyly and preaxial triphalangism of the hindlimb at a high incidence. Our observations showed that the PCD in the preaxial necrotic zone was found to be delayed or absent on day 11 of pregnancy. Histological analyses of these fetuses showed that the preaxial apical ectodermal ridge (AER) of the hindlimb was hyperplastic and consisted of several irregular layers. In observation of the whole-mount in situ hybridization, we detected the anterior-extended overexpression of Hoxd-11 and Hoxd-13 genes in the mesenchyme cells and the overexpression of Fgf4 and Fgf8 genes in the anterior region of the AER of hindlimbs of BrdU-treated fetuses. Our study shows that the injection of BrdU changed the PCD and gene expression during limb development and induced time-specific limb malformations during fetal development. This examination of the changes of the PCD and gene expression will be useful markers for the investigation of toxicities and teratologieties of other chemicals now present in the world environment.

Developmental toxicity of acephate by gavage in mice.

Acephate (O,S - dimethyl acetyl phosphoramidothioate), an organophosphate insecticide, was evaluated for its potential to produce developmental toxicity in mice after oral administration. Pregnant ICR (CD-1) mice were given sublethal doses of 0 (distilled water), 7, 14, and 28 mg/kg/day acephate by gavage on Gestation Days 6 through 15. Maternal effects in the 28 mg/kg/day dose group included cholinergic signs, decreased body weight at 15 and 18 days of gestation, and decreased absolute and relative brain weight. Placental weight was also decreased and liver weight was increased in the high dose group. Absolute and relative brain weight was decreased in the 14 mg/kg/day group. No maternal effects were apparent in the 7 mg/kg/day dose group. Maternal exposure to acephate during organogenesis significantly affected the number of implantations, number of live fetuses, number of early resorptions, mean fetal weight, and the incidence of external and skeletal malformations in the 28 mg/kg/day dose group. No visceral malformations were observed. On the basis of the present results acephate showed maternal and developmental toxicity at 28 mg/kg/day.

Polydactyly and fetal hydantoin syndrome: an additional component of the syndrome?

We report a 3-year-old girl with fetal hydantoin syndrome (FHS) whose mother had received phenytoin 600 mg/day throughout gestation. She had growth retardation, mental deficiency, craniofacial dysmorphism and iris colomobata specific to FHS. However, the patient did not have the distal phalangeal hypoplasia which is associated with FHS; instead, she had polydactyly of the right foot. This seems to be the first FHS case in the literature with polydactyly.

A tragédia da talidomida e o advento da teratologia experimental / The thalidomide tragedy and the birth of experimental teratology

Avaliou-se o desenvolvimento histórico da "Tragédia da Talidomida", desde a utilizaçao inicial da droga na Alemanha Ocidental, seguindo sua comercializaçao em vários países da Europa, bem como do impedimento de sua fabricaçao nos E.U.A. Inicialmente prescrita como "autêntica panacéia" em várias áreas da prática médica, a talidomida foi amplamente consumida por gestantes, causando a maior epidemia iatrogênica da História da Medicina, a partir do final da década de 1950 até a suspeita de sua açao teratogênica, em bases epidemiológicas, por Lenz e McBride, publicada em novembro de 1961, e provocando cerca de 1O.OOO vítimas mundiais. Paralelamente ao amplo dano teratológico causado pela droga, analisou-se sua repercussao revolucionária sobre a evoluçao metodológica dos levantamentos epidemiológicos, técnicas anamnésticas e, principalmente, na avaliaçao dos efeitos embriotóxicos de novos medicamentos e agentes terapêuticas utilizados por gestantes, estabelecendo as bases modernas da Teratologia Experimental e recapitulando o desenvolvimento da Ciência em face de problemas práticos surgidos em determinados períodos históricos. Reviu-se a epidemiologia das malformaçoes congênitas de etiologia genética e causadas por agentes exógenos, principalmente aqueles representados por drogas e medicamentos responsáveis por inúmeros complexos sindrômicos malfonnativos. como o presente na síndrome da talidomida (ST). Apreciou-se a "Tragédia da Talidomida" no Brasil com base no levantamento epideniiológico contido no processo indenizatório das "Vítimas da Talidomida" brasileiras, através da sua análise histórica, desde a introduçao dos medicamentos contendo talidomida no país, sua comercializaçao e proibiçao, bem como a fundaçao de associaçoes de auxílio às "Vítimas da Talidomida". Finalmente, discutiu-se o diagnóstico diferencial da ST e de inúmeros complexos malformativos e defeitos congênitos presentes nos 252 pretendentes a indenizaçao, analisando-se o tipo e a severidade das malformaçoes, os medicamentos utilizados, a evoluçao epidemiológica e a distribuiçao geográfica dos portadores da ST no Brasil.

Antimitotic and teratogenic effects of acyclic nucleotide analogues 1-(S)-(3-hydroxy-2-phosphonomethoxyethyl)cytosine (HPMPC) and 9-(2-phosphonomethoxyethyl) adenine (PMEA).

The acyclic nucleotide analogues, HPMPC and PMEA, differ in their in vitro effect on the genetic material of eukaryotic cells. While HPMPC exerts a cytostatic effect on eukaryotic cells in vitro, PMEA has a genotoxic activity. These results correspond with the mode of embryotoxic action of these compounds: HPMPC exhibits a general embryolethal effect, whereas PMEA is apparently teratogenic and interacts with the mutant allele producing preaxial polydactyly of the hind limbs.