ABSTRACT Our recent study clearly shows that fetuses are exposed to multiple chemicals including endocrine disruptors in Japan. Although the embryo and fetus stages are the most sensitive period to chemicals in humans' life cycle, the health effects of the chemicals such as endocrine disruptors to them are largely unknown. The conventional risk assessment method cannot assess the risk to fetuses precisely. Now we need a new risk assessment, in which the target is fetuses and not the adults, in addition to the conventional risk assessment At the same time, we also need a new strategy to practically eliminate the risk for the future generations. To make the strategy effective, we suggest a new approach to reduce the risk and avoid the possible adverse health effects, using primary, secondary and tertiary preventions as they are used in public health. We also suggest a new concept of “pre-primary prevention” to reduce the risk for fetuses. Furthermore, to make this method even more practical, we suggest a new risk communication method. In this paper, we present a framework of risk avoidance of multiple chemical exposure to fetuses.
ABSTRACT Antenatal sex-hormone exposure induces lesions in mouse reproductive organs, which are similar to those in humans exposed in utero to a synthetic estrogen, diethylstilbestrol. The developing organisms including rodents, fish and amphibians are particularly sensitive to exposure to estrogenic chemicals during a critical window. Exposure to estrogens during the critical period induces long-term changes in reproductive as well as non-reproductive organs, including persistent molecular alterations. The antenatal mouse model can be utilized as an indicator of possible long-term consequences of exposure to exogenous estrogenic compounds including possible environmental endocrine disrupters. Many chemicals released into the environment potentially disrupt the endocrine system in wildlife and humans, some of which exhibit estrogenic activity by binding to the estrogen receptors. Estrogen responsive genes, therefore, need to be identified to understand the molecular basis of estrogenic actions. In order to understand molecular mechanisms of estrogenic chemicals on developing organisms, we are identifying estrogen responsive genes using cDNA microarray, quantitative RT-PCR, and differential display methods, and genes related to the estrogen-independent vaginal changes in mice induced by estrogens during the critical window. In this review, discussion of our own findings related to endocrine distuptor issue will be provided.
ABSTRACT Monitoring of environmental chemicals in Japan has revealed that several endocrine active chemicals are in river water, sediments, and wildlife as well as in the human umbilical cord. In 2001, risk assessments of tributyltin and nonylphenol have been conducted by the Ministry of the Environment, Japan. Risk assessments of di(2-ethylhexyl)phthalate and di-isononyl phthalate have also been performed by the Ministry of Health, Labour and Welfare using a toxicological point of view in 2001. In this review, an overview of recent progress in endocrine disruptor research in Japan will be provided.
ABSTRACT We report here the results of fetal cell enrichment from maternal blood in 58 pregnant women by the use of magnetic activated cell sorting (MACS) with erythroblast-specific and/or maternal cell specific antibodies. Two approaches were compared; one-step MACS to enrich CD71+ (a membrane-bound marker) or GPA+ (another marker, glycophorin A) fetal cells versus two-step MACS to deplete CD14+ maternal cells and subsequently to enrich fetal (CD71+ or GPA+) cells. The existence of fetal cells was ensured by both FISH with Y-specific probes and karyotyping of respective anuniotic and/or chorionic vullus cells, the results being applied for comparison of detection rate for XY fetuses between the two MACS procedures.
In 24 (38.8%) of the 58 blood samples examined, Y-positive cells were observed by FISH, whereas there were 38 true XY fetuses later confirmed by karyotyping, including two cases of 47, XY,+21. On the other hand, in Y-negative cells by FISH, there were two cases of 47, XX,+18. The average number of cells sorted did not differ among one-step MACS procedures with anti-CD14, anti-CD71 and anti-GPA antibodies. With the latter, 12 (75%) of 16 Y-positive fetuses were detected, while only one (20%) of 5 Y-positive fetuses was detected by two-step MACS with anti-CD14/anti-GPA antibodies. The detection rate significantly varied (p = 0.0024) between the two procedures, although the numbers of cases examined were small. There was no statistical difference (p < 0.05) between one-step and two-step MACS with other combinations of antibodies. These findings indicate that one-step MACS using the anti-GPA antibody is more effective than two step MACS for enrichment of fetal cells from maternal blood.
ABSTRACT Pregnant rats were fed an ethanol-containing liquid diet between gestational days 10 and 21. The optic nerves of their litters at 49 days of age were examined using quantitative stereological procedures. Cross-sectional areas of the optic nerve in ethanol-exposed rats were significantly smaller than those in controls. This was reflected in the reduced number of myelinated fibers, but not of non-myelinated fibers. The size distribution histogram indicated a decreased number of small axonal-diameter myelinated fibers in ethanol-exposed rats. The results suggested optic nerve hypoplasia hi ethanol-exposed rats characterized by a selective loss of small-diameter myelinated fibers.
ABSTRACT The time of origin of motor neurons and their distribution in the spinal cord was studied in rat embryos by combining whole-embryo culture and the Islet-1 inununostaining technique. Cells immunostained for Islet-1 appeared in the trunk neural tube by 27 hours (corresponding to E10.625) in culture of E9.5 embryos, at which time the cell number of the neural tube in a transverse section was about 200. When the neural tube retarded developmentally by lithium treatment, the time of appearance of the motor neurons was delayed to 33 hours in culture (corresponding to E10.875), but the cell number of the neural tube was about 200. After the initial appearance of motor neurons in the ventral aspect of the neural tube, they distributed in a group in the periphery of the basal plate by 48 hours (corresponding to E11.5) in culture, although in the retarded neural tube the number of motor neurons was small and they did not form a cluster. The percentage of Islet-1-positive cells at the point of the same cell number of the trunk neural tube in the transverse section was higher in the retarded embryos than in controls. These results suggest that motor neurons begin to appear when the cell number of the neural tube in the transverse section becomes about 200 and their initial development is more stable than overall neural tube development.
ABSTRACT We compared the structures of the femoral head (FH) of neonates between normal and operated legs with restrained fetal movement using an exo utero technique. At embryonic day (E) 16.5, one hind limb was sutured onto the embryonic membrane and the fetuses were allowed to develop exo utero until the term (E22.5). There was no significant difference in the largest diameter of the FH between the non-operated and operated side FH in the operated neonates and the FH of the non-operated neonates. By scanning electron microscopy, roughness and collagen fiber bundles, which were detected on the surface of the operated side FH at E18.5, disappeared at E22.5. However, the operated side FH was deformed and the surface cell arrangement was more irregular than that of the controls at E22.5 by light microscopy. These results suggest that the abnormality of cell arrangement caused by the restraint of fetal movement may induce the deformity and irregularity of the FH surface, although this operation may not disturb the basic cellular activities such as cell proliferation as well as the secretion of cartilage matrix and collagen fibers. To further investigate the recovery process in the operated newborns after releasing the restraint, we bred them artificially for a considerable period after birth. The operated side FH surface of the neonate bred for 45 hours was smoother than that at E22.5 and similar to that of the non-operated side FH. This result suggests that the proper movement of the extremities after birth may recover the deformity caused by restrained fetal joint movement.
ABSTRACT Midline cervical cleft is a rare congenital developmental anomaly of the ventral neck. Less than 100 cases have been reported in published journals to date (Ayache et al., 1997). It is usually found as congenital scar-like skin defect or cord-like contractive abnormality of the skin at the ventral neck. Unlike “median cervical cyst” or “lateral cervical cyst”, midline cervical cleft usually has no anatomical association with the hyoid bone. We will present a case of midline cervical cleft without fistula but with very small protuberant tissue. The subject was operated at the age of 5 months. We will discuss the clinical aspect and surgical management of this infrequent anomaly.