全胚胎体外培养方法筛查致畸原的应用

全胚胎体外培养技术是将孕第９．５天的大鼠胚胎从子宫移至体外培养，培养期间在培养基中加入不同的化合物，由于排除了母体和胎盘因素，可以观察到这些化合物对胚胎生长发育的直接影响。应用该技术研究了青霉素、敌枯双、放线菌素Ｄ和高浓度葡萄糖四种化合物对胚胎生长发育的直接影响，结果发现在体外培养时也可导致胚胎死亡、畸形和胚胎生长发育迟缓，所导致的畸形与在整体动物实验结果相同。同时发现化合物在导致胚胎死亡、畸形和生长发育迟缓方面具有明显的剂量－效应关系。通过比较这种化合物导致胚胎死亡、畸形和发育迟缓的剂量－效应曲线的关系，推测其导致胚胎畸形的可能性以及畸形胚胎存活的可能性，从而推测化合物在实际中真正致畸的可能性。     

Teratogen-induced apoptosis may be affected by immunopotentiation

Intra-uterine immunization of mice with paternal allogeneic or xenogeneic (rat) splenocytes was found to increase embryo tolerance to cyclophosphamide (CP)-induced teratogenesis. As the CP-induced teratogenic effect was shown to be associated with apoptosis, the present study was designed to investigate whether the protective effect of immunopotentiation may be realized via an alteration of CP-induced apoptosis. Various doses of CP were injected intraperitoneally into ICR mice on day 12 of pregnancy. Intra-uterine immunization with xenogeneic rat splenocytes was carried out 3 weeks before mating. Implantation sites, resorptions, live and dead fetuses, as well as soft tissue anomalies and external malformations, were recorded to evaluate the CP-induced embryotoxic effect. In parallel, flow cytometric analysis and DNA fragmentation assay were used for evaluation of CP-induced apoptosis in limbs, tail and whole embryos. The treatment of mothers with a high dose of CP induced the death of almost all embryos and striking fetal growth retardation in survivors. This strong embryotoxic effect was accompanied by very prominent DNA degradation in cells collected from whole embryos. Immunostimulation caused a dramatic decrease of embryonal loss (by ˜ 50%) and a significant (about 30%) increase in fetal weight. Such an increase in fetal survival and in fetal weight was found to be accompanied by a clear decrease in apoptosis level in embryo cell populations as judged by DNA gel electrophoresis with subsequent quantitation of DNA fragmentation in negatives by an image analysis technique. After treatment with a low dose of CP, a decrease in the proportion of fetuses with limb and tail anomalies in immunized females was accompanied by a decrease in the proportion of apoptotic nuclei in cells taken from limbs and tails. The results of this study suggest that the teratogen-induced apoptosis may, at least partly, be dependent on fetomaternal immune interactions.     

Embryotoxic/teratogenic potential of halothane

Summary The embryotoxic/teratogenic potential of halothane was evaluated on the basis of available data obtained in an extensive literature search. It was found that halothane induced ultrastructural visible changes in the offspring of rats exposed to concentrations of 10 ppm during gestation. These consisted of degenerative changes in the cerebral cortex and, in particular, the weakening of cell membranes and the vacuolisation of the Golgi-complex. Macroscopically visible morphological changes were seen in rats only after exposure to concentrations equivalent to 320-fold (1600 ppm) the MAK value (maximum concentration value at the workplace). Furthermore, behavioural disorders were seen when exposure to concentrations 10 ppm occurred during gestation and after parturition. In mice, only macroscopical investigations were performed. The first disturbances scored were only visible as retardation in the offspring, and occurred after exposure to concentrations of halothane 200-fold (1000 ppm) the MAK-value. In the rabbit, anaesthetic concentrations of 22 000 ppm. halothane did not result in an embryotoxic/teratogenic effect.The individual epidemiological findings in humans were discussed controversially. The studies are inconclusive in establishing an embryotoxic/teratogenic risk following sole exposure to halothane at the MAK level, since mixed exposures occurred and data on the concentrations of halothane in the inhaled air were missing. Therefore, the decision on whether halothane can impair intrauterine development is primarily based on the animal experimental findings. As long as a threshold value has not been established for the observed lesions, halothane should not be inhaled during pregnancy.     

Stephen L. Gans Distinguished Overseas Lecture. The neural crest in pediatric surgery

Aim

This review higlights the relevance of the neural crest (NC) as a developmental control mechanism involved in several pediatric surgical conditions and the investigative interest of following some of its known signaling pathways.

Methods

The participation of the NC in facial clefts, ear defects, branchial fistulae and cysts, heart outflow tract and aortic arch anomalies, pigmentary disorders, abnormal enteric innervation, neural tumors, hemangiomas, and vascular anomalies is briefly reviewed. Then, the literature on clinical and experimental esophageal atresia-tracheoesophageal fistula (EA-TEF) and congenital diaphragmatic hernia (CDH) is reviewed for the presence of associated NC defects. Finally, some of the molecular signaling pathways involved in both conditions (sonic hedgehog, Hox genes, and retinoids) are summarized.

Results

The association of facial, cardiovascular, thymic, parathyroid, and C-cell defects together with anomalies of extrinsic and intrinsic esophageal innervation in babies and/or animals with both EA-TEF and CDH strongly supports the hypothesis that NC is involved in the pathogenesis of these malformative clusters. On the other hand, both EA-TEF and CDH are observed in mice mutant for genes involved in the previously mentioned signaling pathways.

Conclusions

The investigation of NC-related molecular pathogenic pathways involved in malformative associations like EA-TEF and CDH that are induced by chromosomal anomalies, chemical teratogens, and engineered mutations is a promising way of clarifying why and how some pediatric surgical conditions occur. Pediatric surgeons should be actively involved in these investigations.     

Acitretin (Neotigason?) A review of pharmacokinetics and teratogenicity and hypothesis on metabolic pathways

Acitretin was introduced as a replacement for etretinate, the ethyl ester of acitretin. Acitretin is eliminated at a much faster rate than etretinate. Although both drugs are teratogens, the replacement was important especially as it allowed for a much shorter post-medication period in which pregnancy should be precluded. Recent findings showed the presence of etretinate in the plasma of acitretin-treated patients. This article gives a review of known metabolic pathways of the retinoids and tries to elucidate the possible conversion of acitretin into etretinate after acitretin ingestion.     

Maximizing the Health of Women with Epilepsy: Science and Ethics in New Drug Development

Summary: Issues of unique concern to women with epilepsy largely arise from gender-based physiological differences. Female sex steroid hormones may alter the expression of epilepsy and the efficacy of antiepileptic drugs (AEDs). Seizures and AEDs in turn affect the hypothalamic-pituitary axis and can adversely impact reproductive function and bone health. Maternal seizures and exposure to AEDs may compromise fetal development. At this time, women with epilepsy and their medical caretakers do not have access to all the information necessary to formulate a treatment plan that will have the least impact on reproductive and general health. In part, this is because reproductive aged women are excluded from the earliest phases of drug testing and pregnant and lactating women are excluded from all aspects of new drug development. Therefore, as new AEDs enter the marketplace, women with epilepsy must decide whether a new AED is appropriate for therapy based on very limited information. Postmarketing surveillance of gender-specific adverse effects, as with all adverse effects, depends on voluntary reporting. Only a small percentage of significant adverse events are believed to be captured by the present system. Consumers, ethicists, and some physician groups are now arguing that women should be included in all aspects of the development of drugs they will ultimately use–even pregnant and lactating women. Some of the issues of concern for women with epilepsy regarding epilepsy treatment, reproductive function and general health will be reviewed, followed by a discussion of the drug development process and how it does, and could better, address the concerns of women.     

Pregnancy outcome after prenatal exposure to bleomycin, etoposide and cisplatin for malignant ovarian germ cell tumors: report of 2 cases

Bleomycin plus etoposide and cisplatin seem to be a promising alternative for women with ovarian cancer. We are reporting two cases with favorable pregnancy outcome after exposure to these chemotherapeutic agents at the second and third trimesters of pregnancy. A pregnant woman with a stage Ic yolk-sac tumor underwent a right oophorectomy with omentectomy, and received five cycles of bleomycin, etoposide and cisplatin from the 22nd week of pregnancy until delivery. The second case was a pregnant woman with a stage Ia immature teratoma who underwent right salpingo-oophorectomy and received two cycles of bleomycin, etoposide and cisplatin starting at 30th week of pregnancy. The two patients did not have any evidence of recurrence of ovarian cancer for 6 and 2 years, respectively. Their babies did not have any evidence of minor or major malformations, and showed normal neurological development at 6 and 2 years of follow-up, respectively.     

Pregnancy outcomes and factors associated with voluntary pregnancy termination in women who had been treated for acne with isotretinoin

Objective. We aimed to study the pregnancy outcomes of women exposed to isotretinoin and to identify the factors influencing their decision to request an abortion. Methods. The study prospectively identified 79 women who had been treated for acne with isotretinoin during the periconceptional period, and who were followed up until completion of their pregnancy. Characteristics of exposure and doses were self-reported by participants. Results. Of the 56 participants who decided to continue their pregnancy, there were 11 spontaneous abortions and 44 women who delivered healthy full-term babies of which 19 had been exposed to isotretinoin <1 month before conception or during pregnancy. In a nominal logistic regression analysis including 68 patients who provided adequate information for analysis, exposure to isotretinoin >2 weeks post-conception and pregnancy termination recommended by the first-contact physician were found to be significantly associated with patients’ decision to undergo elective abortion: adjusted OR = 9.87 (95% CI 1.18–82.34) and 12.51 (95% CI 2.36–66.29), respectively. Conclusions. Our study reports an elevated rate of babies born without evidence of gross malformation or neurofunctional abnormality even tough exposure occurred during the teratogenic risk period. However, caution is recommended since a substantial risk of congenital malformations has been reported with low doses of isotretinoin and at exposures limited to early pregnancy. We also found that primary-care physicians may influence patients’ decision to request pregnancy termination independently of their timing of exposure to isotretinoin.     

Angiotensin II Receptor Blockers in Pregnancy: A Case Report and Systematic Review of the Literature

Objective: To describe the case of a woman exposed to angiotensin-II receptor blockers (ARBs) in the preconceptional period and to systematically review the literature on the safety of these drugs when used by pregnant women. Methods: The case was identified at the Korean Motherisk Program (Seoul). For the systematic review, we searched the PubMed for case reports, case series, and post-marketing surveys. Results: A hypertensive woman was exposed to irbesartan prior to conception. The embryo had delayed development of upper and lower extremities and decreased digital groove. A karyotype identified a 45,XO Turner syndrome. The patient had a spontaneous abortion. Including the case reported here, 64 published cases were identified in total; 57.8% had favorable and 42.2% had unfavorable outcomes. Duration of treatment during pregnancy among women who had adverse fetal outcomes was 26.3 ± 10.5 weeks (mean ± SD), compared with 17.3 ± 11.6 weeks in those who had favorable outcomes (p?=?0.04). Conclusions: Exposure to ARBs for a period longer than the first trimester of pregnancy appears to be associated with a high risk for adverse fetal outcomes.