• Animal cells and systems
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• v.5 no.4
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• pp.327-331
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• 2001

There is a critical developmental period during which brain sexual differentiation proceeds irreversibly under the influence of gonadal hormone. Recently, kinesin superfamily-associated protein 3 (KAP3) gene expressed during the 'critical period' of rat brain differentiation was identified by us (Choi and Lee, 1999). KAP3 functions as a microtubule-based motor that transports membranous organelles anterogradely in cells, including neurons (Yamazaki et al., 1996). mRNA level of KAP3 gene markedly increased before the initiation of puberty. Neonatal treatment of estrogen clearly inhibited the prepubertal increase in KAP3 mRNA level (Choi and Lee, 1999). In the present study, we aimed to investigate the effects of polychlorinated biphenyls (PCBs), as endocrine disruptors (EDs) on the expression of KAP3 gene during the 'critical period' of rat brain development. In our data, PCBs significantly decreased the expression of KAP3 gene in the fetal (day 17) and the neonatal (day 6 after birth in) male and female rat brains. The body weight and the breeding ability were significantly decreased in the PCBs-exposed rats compared with the control. These results showed that PCBs affect the transcriptional level of brain sexual differentiation related gene, KAP3, in the fetal and the neonatal rat brains. The maternal exposure to the PCBs may lead to toxic response in embryonic brain sexual differentiation and breeding ability after sexual maturation. This study indicates that KAP3 gene may be useful as a gene marker to analyze the molecular mechanism of toxic response in the animal brain development and sexual maturation exposed to PCBs.

• BMB Reports
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• v.32 no.4
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• pp.409-413
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• 1999

The cDNA encoding CMP-NeuAc:lactosylceramide ${\alpha}2$,3-sialyltransferase (GM3 synthase) was isolated from a human fetal brain cDNA library using sequence information obtained from amino acid sequences found in the conserved regions of the previously-cloned mouse GM3 synthase (mST3Gal V) and human sialyltransferases. The cDNA sequence included an open reading frame coding for 362 amino acids, and the primary structure of this enzyme predicted all the structural features characteristic of other sialyltransferases, including a type II membrane protein topology and both sialylmotifs. Comparative analysis of this cDNA with mST3Gal V showed 85% and 86% identity of the nucleotide and amino acid residues, respectively. The expression of this gene is highly restricted in both human fetal and adult tissues.

• International Journal of Stem Cells
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• v.15 no.1
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• pp.41-59
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• 2022

The emergence of brain organoids as a model system has been a tremendously exciting development in the field of neuroscience. Brain organoids are a gateway to exploring the intricacies of human-specific neurogenesis that have so far eluded the neuroscience community. Regardless, current culture methods have a long way to go in terms of accuracy and reproducibility. To perfectly mimic the human brain, we need to recapitulate the complex in vivo context of the human fetal brain and achieve mature neural circuitry with an intact cytoarchitecture. In this review, we explore the major challenges facing the current brain organoid systems, potential technical breakthroughs to advance brain organoid techniques up to levels similar to an in vivo human developing brain, and the future prospects of this technology.

• Development and Reproduction
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• v.1 no.2
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• pp.189-202
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• 1997

The hypothalamic peptide GnRH plays a central role in the regulation of the mammalian reproductive axis. Recent studies suggested that GnRH stimulates or inhibits the ovarian steroidogenesis and gametogenesis directly. Our previous report indicated that GnRH gene is expressed in adult rat ovary as well as in hypothalamus and that the expressed GnRH may induce the follicular atresia and apoptosis of ovarian granulosa cells in rat. Therfore, we studied whether GnRH gene is expressed in the mouse fetal ovary, when the germ cells are degenerating by apoptosis during gonad diffeerentiation. Mouse fetal gonads were obtained on the 12, 15,18 and 20th day of gestation from the mother mice superovulated (10 IU PMSG and 10 IU hCG) and mated. The morphological changes of fetal ovaries were examined histochemically by hematoxylin-eosin staining. The fetal sex was confirmed by PCR methods for sexing. RT-PCR methods were used to examine the expression of GnRH gene and the sex steroid hormones were determined by conventional radioimmunoassays. The levels of estradiol (E) and progesterone (P) were increaseduntil 18th day of gestation and then E was decreased just before parturition. The morphological changes of fetal gonadal tissue sections showed the ovarian development and coincided with the result of PCR analysis for sexing using ovary- or testis- specific oligonucleotide primers. Immunoreactive GnRH in placenta was decreased gradually until the end of gestation but fetal brain and ovarian GnRH were increased. The level of GnRH gene expression was increased during fetal ovarian development from 12 till 18th day and decreased suddenly on 20th day just before birth. From these results, it is suggested that ovarian GnRh may play a regulatory role on the germ cell differentiation of fetal ovary.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.100-103
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• 1998

아까바네 바이러스로 인하여 유산된 태아의 뇌조직으로부터 '아까바네 바이러스 항원을 면역학적으로 검출하는 기법을 확립하였다. 아까바네 바이러스로 유산된 태아의 뇌는 조 직이 거의 손실되거나 유약하여 부검 즉시 포르말린 등에 보존하여야 하므로, 포르말린에 보존 된 뇌조직을 절편 하여 파라핀으로 포매된 조직표본으로부터 immunohistochemistry 방법으로 아까바네 바이러스 특이 항원을 검출하였다. 또한 이들 조직으로부터 직접 마우스 뇌내 접종과 조직배양내 바이러스 분리를 통하여 immunohistochemistry 법의 항원 검출 효율이 높음을 확 인하였다. 유산된 태아의 뇌조직에서 단크론 항체를 이용한 항원 검출 실험에서 세포의 세포질 내에서 아까바네 특이 항원이 검출되었고 hematoxylin-rosin 대조 염색으로 항원을 특이적으로 구분하여 진단할 수 있었다. 바이러스에 감염된 세포는 조직학적으로 변성이 심한 부위에서 다 수 관찰되었고 맥관계에 가까운 세포에서도 독립적으로 감염된 세포가 관찰되었다.

• Toxicological Research
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• v.2 no.1
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• pp.37-50
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• 1986

This paper describes the effects of nitrofen (Hi-TOK), a herbicide on the fetuses of rats. The results were observed as follows: The internal soft tissue anomalies were classified as diaphragmatic hernia, cardiac malformation (T.G.V., V.S.D., S.V.), dilatation of ventricle in brain, dilatation of renal pelvis, underdevelopment of fetal lung, shortening of cortex length and increasing of immatured glomeruli counts in the fetal kidney. The heart and diaphragm appear to be the target organs.

• 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.

• BMB Reports
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• v.52 no.10
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• pp.577-588
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• 2019

DNA methylation at CpG sites is an essential epigenetic mark that regulates gene expression during mammalian development and diseases. Methylome refers to the entire set of methylation modifications present in the whole genome. Over the last several years, an increasing number of reports on brain DNA methylome reported the association between aberrant methylation and the abnormalities in the expression of critical genes known to have critical roles during aging and neurodegenerative diseases. Consequently, the role of methylation in understanding neurodegenerative diseases has been under focus. This review outlines the current knowledge of the human brain DNA methylomes during aging and neurodegenerative diseases. We describe the differentially methylated genes from fetal stage to old age and their biological functions. Additionally, we summarize the key aspects and methylated genes identified from brain methylome studies on neurodegenerative diseases. The brain methylome studies could provide a basis for studying the functional aspects of neurodegenerative diseases.

• Journal of Life Science
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• v.13 no.3
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• pp.291-297
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• 2003

A human endogenous retroviral family (HERV-W) has recently been described that is related to multiple sclerosis-associated retrovirus (MSRV) sequences that have been identified in particles recovered from monocyte cultures from patients with multiple sclerosis. Two pol fragments (HWP-FB10 and HWP-FBl2) of HERV-W family were identified and analysed by the PCR approach with cDNA library of human fetal brain. They showed 89 percent nucleotide sequence similarity with that of the HERV-W (accession no. AF009668). Deletion/insertion or point mutation in the coding region of the pol fragments from human fetal brain resulted in amino acid frameshift that induced a mutated protein. Phylogenetic analysis of the HERV-W family from GenBank database indicates that the HWP-FB10 is very closely related to the AC000064 derived from human chromosome 7q21-q22. Further studies on the genetic relationship with neighbouring genes and functional role of these new HERV-W pol sequences are indicated.

• Korean Journal of Veterinary Research
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• v.62 no.4
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• pp.32.1-32.4
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• 2022

A Hanwoo cow with a delayed gestation and abdominal distension was delivered following PGF_2α injection. There was excessive amniotic fluid, and a male calf was delivered but died immediately. The calf had no eyes and nose, and a cleft palate on the upper jaw. Gross appearance and computed tomography image showed that upper teeth were spread out on both sides due to cleft palate in the upper jaw, and lower jaw and teeth were positioned upward. There were no other brain parts except cerebellum. These findings show a rare case of hydramnios related to fetal congenital deformity in a Hanwoo cow.