• Journal of Life Science
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• v.11 no.5
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• pp.447-456
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• 2001

We have recently demonstrated that the fluoroquinolone antibacterial DW-116 caused a significant developmental toxicity in rats. The present study was conducted to determine whether the development toxicity induced by DW-116 treatment was the result of malnutrition fro reduced food intake or the direct effects of test chemical on conceptuses. The test chemical was administered by gavage to pregnant rats from gestational days 6 through 16 at dose levels of 0 and 500 mg/kg/day. A pair-feeding study was also performed in which the pregnant rats received the same amount of diet consumed by the DW-116-treated pregnant rats. All dams were subjected to caesarean section on day 20 of gestation and their fetuses were examined for examined for external, visceral, and skeletal abnormalities. In this treatment group, the maternal toxicities included increased abnormal clinical signs, decreased maternal body weight, suppressed body weight gain during treatment and posttreatment periods, and reduced food intake. The significant developmental toxicities included increased fetal deaths, decreased live fetuses, reduced fetal body weight and placental weight, increased incidence of fetal abnormalities, and increased fetal ossification delay. In this pair-fed group, however, slight maternal toxicities including decreased body weight and suppressed body weight gain during treatment period were observed in comparison with the control group, and minimal development toxicities including reduced fetal and placental weights and increased fetal ossification delay were found. The number of fetal deaths and live fetuses, and the incidences of malformed fetuses and litters with affected fetuses were comparable to the control values. Based on the results, it could be concluded that the development toxicity observed in the treatment group is attributable to the direct effects of Dw-116 treatment, but not to the maternal malnutrition from reduced food consumption during pregnancy.

• Toxicological Research
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• v.17 no.4
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• pp.279-286
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• 2001

Recently, there is an increasing nationwide concern in Korea that exposure to electric and magnetic fields in the home environment may not be safe in humans. To identify possible effects of horizontally polarized magnetic fields (MF) exposure on embryo-fetal development, timed-mated female Sprague-Dawley rats (24/group) received continuous exposure to 60 Hz MF at field strengths of 0 Gauss (sham control), 50mG,833 mG, or 5000 mG. Dams received MF of sham exposures for 22hr/day on gestation days 6 through 20. Experimentally generated MF were monitored continuously througout the study. There was no evidence of maternal toxicity of developmental toxicity in any MF-exposed groups. Mean maternal body weight, organ weights, and gross findings in groups exposed to MF did not differ from those in sham control. No significant differences in fetal deaths, fetal body weight, and placental weight were observed between MF-exposed groups and sham control. External, visceral, and skeletal examination of fetuses demonstrated no significant differences in the incidence of fetal malformations between MF-exposed and sham control groups. In conclusion, exposure of pregnant Sprague-Dawley rats to 60 Hz at MF strengths up to 5000 mG during gestation day 6-20 did not produce any biologically significant effect in either dams of fetuses.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.6
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• pp.693-699
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• 2010

Imprinted genes are essential for fetal development, growth regulation, and postnatal behavior. However, little is known about imprinted genes in livestock. We hypothesized that certain putatively imprinted genes affected normal peri-implantation development such as embryo elongation, initial placental development, and preparation of implantation. The objective of the present study was to investigate the mRNA expression patterns of several putatively imprinted genes during the porcine peri-implantation stages from day 6 to day 21 of gestation. Imprinted genes were selected both maternally (Dlk1, IGF2, Ndn, and Sgce) and paternally (IGF2r, H19, Gnas and Xist). Here, we report that the maternally imprinted gene IGF2 was expressed from day 6 (Blastocyst stage), but Dlk1, Ndn, and Sgce were not expressed in this stage. These genes were first expressed between days 12 and day 14. All the maternally imprinted genes studied showed significantly high expression patterns from day 18 of embryo development. In contrast, paternally imprinted genes IGF2r, H19, Gnas, and Xist were first expressed from day 6 of embryo development (BL). Our data demonstrated that the expression of H19 and Gnas genes was significantly increased from day 14 of the embryo developmental stage, while IGF2r and Xist only showed high expression after day 21. This study is the first to show that the putatively imprinted genes were stage-specific during porcine embryonic development. These results demonstrate that the genes studied may exert important effects on embryo implantation and fetal development.

• Journal of Korean Neurosurgical Society
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• v.56 no.6
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• pp.488-491
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• 2014

Objective : The purpose of this study was to investigate the prenatal hypoxic effect on the fetal brain development. Methods : We used the guinea pig chronic placental insufficiency model to investigate the effect of hypoxia on fetal brain development. We ligated unilateral uterine artery at 30-32 days of gestation (dg : with term defined as -67 dg). At 50 dg, 60 dg, fetuses were sacrificed and assigned to either the growth-restricted (GR) or control (no ligation) group. After fixation, dissection, and sectioning of cerebral tissue from these animals, immunohistochemistry was performed with NeuN antibody, which is a mature neuronal marker in the cerebral cortex. Results : The number of NeuN-immunoreactive (IR) cells in the cerebral cortex did not differ between the GR and control groups at 50 dg. However, the number of NeuN-IR cells was lesser in GR fetuses than in controls at 60 dg (p<0.05). Conclusion : These findings show that chronic prenatal hypoxia affect the number of neuron in the cerebral cortex of guinea pig fetus at 60 dg. The approach used in this study is helpful for extending our understanding of neurogenesis in the cerebral cortex, and the findings may be useful for elucidating the brain injury caused by prenatal hypoxia.

• Development and Reproduction
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• v.11 no.1
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• pp.1-11
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• 2007

Specific endometrial preparation should occur during periimplantation period. That is a progress of serial differentiation and is absolute in implantation of embryo and successful pregnancy. Remodeling of tissues shown during embryogenesis is regulated by various factors including extracellular matrix (ECM). Marked changes during pregnancy are including embryo migration, decidual response, and differentiation of placenta in placental animals including human. These changes to successful implantation in embryo and uterus have to prepare the competence for attachment of embryo and uterus, and invasion defense of uterus. During these changes, ECM dramatically changes for maintaining the uterine and embryonic functions. The major component of most connective tissue is collagens. It is very complex and hard to explore the mechanisms for ECM modulation. Recently using high throughput methodology, PCR-select cDNA subtraction method, microarray, many candidate genes have been identified. Steroid hormones have fundamental role in implantation and maintenance of pregnancy. Dermatopontin, a regulator of collagen accumulation, is regulated spatio-temporally in the uterus by primarily progesterone through progesterone receptors at the time of implantation. Modulation of extracellular matrix is critically regulated by cascade of gene net-works which are regulated by cascade of sex steroid hormones. Pathological regulation of uterine extracellular matrix reported in diabetic patients. To know the extracellular modulation is essential to understanding implantation, feto-placental development and overcome the paths involved in female reproduction. Though ECM composed with very various components and it is complex, the present review focused on the fate of collagens during periimplantation period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.4
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• pp.438-449
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• 1996

Development of alimentary tract and nutrient absorption in embryo of the viviparous teleost surfperch, Ditrema temmincki were investigated with histochemical methods. Just after hatching mouth of the embryo was opened, and the end part of alimentary tract was opened in TL 4.0 mm. Mucosal folds in the alimentary tract appeared at posterior region from TL 5.0 mm. In TL 30.0 mm, the alimentary tract of the embryo could be distinguished into pharynx, esophagus, anterior intestine, mid intestine, posterior intestine, rectum and anus. From over TL 50.0 mm, the internal histological patterns of the alimentary tract showed similar structures as seen in the adult. The mucous cells in the pharynx were positively reacted to PAS in TL 7.0 mm. PAS positive goblet cell appeared in the intestine from 25.0 mm, from TL 30.0 mm in the rectum, from TL 40.0 mm in the anus and from 50.0 mm in the esophagus. Yolky materials were absorbed completely in TL 6.0 mm. PAS positive polysaccharide absorptive cells began to appear at the posterior parts of the intestine in TL 7.0 mm and appeared in TL 13.0 mm at the rectum, in TL 15.0 mm at the anterior intestine and in TL 40.0 mm at the anterior part of anus. During the gestation period, nutrient absorptive type of the embryo within the maternal body is a placental analogues type of metrotrophy.

• Molecules and Cells
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• v.45 no.11
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• pp.846-854
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• 2022

Neurons make long-distance connections via their axons, and the accuracy and stability of these connections are crucial for brain function. Research using various animal models showed that the molecular and cellular mechanisms underlying the assembly and maintenance of neuronal circuitry are highly conserved in vertebrates. Therefore, to gain a deeper understanding of brain development and maintenance, an efficient vertebrate model is required, where the axons of a defined neuronal cell type can be genetically manipulated and selectively visualized in vivo. Placental mammals pose an experimental challenge, as time-consuming breeding of genetically modified animals is required due to their in utero development. Xenopus laevis, the most commonly used amphibian model, offers comparative advantages, since their embryos ex utero during which embryological manipulations can be performed. However, the tetraploidy of the X. laevis genome makes them not ideal for genetic studies. Here, we use Xenopus tropicalis, a diploid amphibian species, to visualize axonal pathfinding and degeneration of a single central nervous system neuronal cell type, the retinal ganglion cell (RGC). First, we show that RGC axons follow the developmental trajectory previously described in X. laevis with a slightly different timeline. Second, we demonstrate that co-electroporation of DNA and/or oligonucleotides enables the visualization of gene function-altered RGC axons in an intact brain. Finally, using this method, we show that the axon-autonomous, Sarm1-dependent axon destruction program operates in X. tropicalis. Taken together, the present study demonstrates that the visual system of X. tropicalis is a highly efficient model to identify new molecular mechanisms underlying axon guidance and survival.

• Child Health Nursing Research
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• v.22 no.4
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• pp.317-325
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• 2016

Purpose: Smoking during pregnancy contributes to the risk of negative health outcomes in mothers and babies. The purposes of this study were to review the harmful effects of maternal smoking during pregnancy on fetal and child development, to discuss if maternal smoking should be criminalized as a form of child abuse, and to explore advocating for fetal rights. Methods: A variety of published literature and legal documents including the Korean constitution, criminal laws, and children's welfare laws were reviewed and critically analyzed. Results: Women who smoke during pregnancy are more likely to experience abortion related to placental dysfunction. Their unborn risk premature birth, fetal growth restriction, low birth weight, neurobehavioral disturbances, and/or other complications and newborn babies are also at risk for complications. The advocates for fetal rights can assert that maternal smoking should be regarded as a crime. Conclusion: Findings show that maternal smoking during pregnancy is a major risk factor for many adverse pregnancy outcomes. Effective strategies and health policies for smoking cessation during pregnancy are required to protect pregnant women and their babies.

• Toxicological Research
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• v.12 no.1
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• pp.137-141
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• 1996

A teratological study was performed using New Zealand White rabbits to examine the teratological potential of Ginkgo biloba extract(EGb 761), which is a known strong platelet activating factor antagonist. Ginkgo biloba extract(EGb 761) was administered per intravenously during the organogenesis period (day 6th to 18th of gestation) of rabbits at dose levels of 7.5, 15, and 30 mg/kg/day. All pregnant females were sacrificed on day 29 of gestation and teratological abnormalities of their fetuses was examined. No statistically significant difference of body weight change between control and treated groups during experimental periods was noted. There was no statistically signifiant difference of numbers of corpus lutes and implantations, fetal death ratio, fetal sex ratio, and placental weight between control and rabbits exposed to three different concentration ranges of Ginkgo biloba extract (EGb 761). No marked external, visceral and skeletal abnormalities related to Ginkgo biloba extract(EGb 761) were observed in the fetuses. In conclusion Ginkgo biloba extract(EGb 761) does not show any effect on implantation or embryonic development.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.277-287
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• 2002

The chemopreventive effects of ginseng on rat carcinogenesis models were investigated, In the present study, the inhibitory effects of white and red ginseng on tumor development were examined using medium-term liver, initiation and medium-term multi-organ carcinogenicity bioassay systems. No modifying potential of the ginsengs was evident in terms of the numbers or areas of glutathione S-transferase placental form (GST -P)-positive foci, which is a marker of preneoplastic lesion in rat livers. However, white ginseng, but not red ginseng was found to decrease the incidences of adenocarcinoma of the small intestine and colon in the medium-term multi-organ carcinogenesis model. These results indicate that white ginseng may have inhibitory effects on progression stage of rat intestinal carcinogenesis, but the influence is not strong. Ginseng is unlikely to have promoting or inhibitory effects in other organs under the present type of experimental conditions. Possible application on ginseng for chemoprevention of colon cancer in humans, can be concluded given the lack of obvious adverse effects.