• 한국동물학회지
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• 제39권1호
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• pp.54-64
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• 1996

Xenopus를 사용하여 후각원판이 정상적인 상태에서 어떠한 과정을 거쳐 발달하는지 연구하였다. 특히 뉴런의 형태적 분화, 초기 발달과 성숙 양상, 축색과 원시전뇌의 접촉 등에 초점을 맞추었다. 후각원판은 stage 23에 외배엽이 두터워진 형태로 처음 나타나는데, 쌍을 이루며 각각은 표피측에 비신경층(NNL)과 안쪽의 신경층(NL)의 두 층으로 되어 있다. stage 26 후에 원판 세포는 NNL세포 틈을 비집고 상피쪽으로 이동하기 시작하며, stage 28이 되면 선단 돌기가 표피 끝에 도달한다. stage 29/30에는 NL의 기부에서 기부 돌기(미래의 축색)가 나타나 stage 32무렵 종뇌에 도달한다. 시냅스는 stage 37/38에 처음 나타난다. 일부 원판 세포들이 후각 뉴런으로 분화하는 동안 많은 원판 세포들은 기저세포로서 후각상피에 그대로 남아 있다. 연구 결과는 뉴런 외배엽의 NL에서 기원하고 지지세포는 NNL층에서 기원함을 보여주었다. 또한 시냅스 형성 전에 뉴런의 분화가 완성됨으로써 후각뉴런의 분화는 뇌의 발달과 독립적으로 일어나며 뇌의 영향을 받지 않는다는 사실을 알 수 있었다.

• Animal cells and systems
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• 제1권3호
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• pp.491-496
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• 1997

When olfactory placodes are transplanted at stages 23/24 from Xenopus laevis to Xenopus borealis hosts of the same age, it is possible to distinguish the cell populations of the host and donor due to the peculiar nuclear Q bands specific to X. borealis. I have replaced the eye anlage in each of a number of X. borealis with the transplanted olfactory placode of an individual X. laevis, or vice versa. In most instances, the placode of the donor fuses with that of the host. When fusion occurs, but not when the host and donor orqans grow separately, the cells of the donor were replaced gradually and according to a characteristic pattern by cells of the host. The basal cells of the donor were the first to be replaced, followed by the more matured cells of the sensory epithelium. This cellular substitution, proceeding in an orderly fashion from bottom to upper layers of the epithelium, depends on the fusion of the two organs. This observation suggests intercellular contacts in the mitotic zone of the two organs favor the host's cells over those of the donor.

• BMB Reports
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• 제42권10호
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• pp.631-635
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• 2009

The heat shock transcription factor (HSF) family consists of at least three members in mammals and regulates expression of heat shock proteins in response to heat shock and proteotoxic stresses. Especially, HSF1 is indispensable for this response. Members of this family are also involved in development of some tissues such as the brain and reproductive organs. However, we did not know the molecular mechanisms that regulate developmental processes. Involvement of HSFs in the sensory development was implicated by the finding that human hereditary cataract is associated with mutations of the HSF4 gene. Analysis of gene-disrupted mice showed that HSF4 and HSF1 are required for the lens and the olfactory epithelium, respectively. Furthermore, a common molecular mechanism that regulates developmental processes was revealed by analyzing roles of HSFs in the two developmentally-related organs.

• International Journal of Oral Biology
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• 제49권2호
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• pp.48-52
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• 2024

This study explores the histological features and Bmp4 expression patterns in the replaced tooth germ of Xenopus laevis. Tooth germ formation starts from the dental placode through epithelial-mesenchymal interactions, involving various signaling pathways such as Fgf, Shh, Bmp, and Wnt. In mice, Bmp4 expression in the dental placode inhibits Pax9 expression in the dental mesenchyme. Although absent in the presumptive dental lamina of birds and toothless mammals, Bmp4 remains conserved in reptiles and fish owing to gene duplication. However, its expression in amphibian tooth germs is poorly understood. Three-month-old X. laevis were employed in this study. Initially, samples underwent paraffin embedding and were sectioned into 5 or 12 ㎛ ribbons for H&E staining and in situ hybridization, respectively. Results revealed teeth appearing in two maxillary rows: the labial side, with prefunctional and functional teeth, and the lingual side, with replaced tooth germs behind functional teeth. Enameloid was observed between the inner dental epithelium and dental mesenchyme at the cap or early bell stages, whereas enamel and dentin formed during the late bell or mineralization stages from the replaced tooth germ. Bmp4 expression was evident in the inner dental epithelium (ameloblasts), dental papilla (odontoblasts), stellate reticulum, and Hertwig's epithelial root sheath. Overall, these findings highlight the conservation of Bmp4 expression in X. laevis tooth development.

• Animal cells and systems
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• 제13권4호
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• pp.411-418
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• 2009

We are reporting the identification, expression patterns, and possible biological functions of zebrafish kif3b (kif3bz) encoding 475 amino acids. Kif3Bz contains the kinesin motor domain, catalytic domain, KISc domain, and one single coiled coil domain. Phylogenetic analysis indicates that kif3bz is a highly conserved gene among the tested vertebrates. First of all, both maternal and zygotic messages of kif3bz were evenly distributed in the blastomeres at 2-cell stage. Its ubiquitous expression throughout the blastomeres continued till 40% epiboly. However, kif3bz transcripts became restricted in Kupffer's vesicle at tailbud and 6-somite stages. At 13-somite stage, kif3bz expression pattern became specific to the telencephalon, diencephalon, trigeminal placode, and somites. Such expression patterns were further intensified in the telencephalon, diencephalons, hind brain, pronephric ducts, optic vesicles, and spinal cord neurons in the 23-somite stage embryos, and last till 24 hpf. We discussed possible functions of Kif3Bz related to the vertebrate embryonic development.

• 대한소아치과학회지
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• 제28권4호
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• pp.709-727
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• 2001

세포자기사(programmed cell death)는 배자발생과정에서 중요한 역할을 하는 정상적인 생리적현상으로 알려져왔다. 생쥐 배자에서 세포자기사에 관한 많은 연구가 있었지만 초기 형태발생기동안의 전반적이고 구체적인 세포자기사 양상에 관한 보고는 없었다. 이에 본 연구에서는 발생 4.5일$\sim$11.5일째의 Balb/c생쥐배자에서 생쥐발생초기의 세포자기사가 일어나는 양상을 알아보았다. 세포자기사가 일어나는 양상은 배자 조직절편과 온전한 배자에 in situ terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) 반응을 시켜 알아보았다. 주머니포배시기 (발생 4.5일째)에는 세포자기사 과정에 있는 세포가 극히 드물게 속세포명이에서 관찰되었다. Egg cylinder시기 초기(발생 $5.0\sim5.5$일째)에는 소수의 세포자기사 세포가 배자외배엽과 배자내배엽, 원시양막공간에서 나타났다. Egg cylinder시기 후반부(발생 $5.5\sim6.5$일)에는 세포자기사 세포가 배자외배엽, 배자내배엽, 원시양막공간 뿐만 아니라 바깥배자외배엽과 바깥배자내배엽 에서도 관찰되었다. Streak 시기 (발생 $6.75\sim7.75$일)에는 많은 세포자기사 세포가 ectoplacental cone부위에서 관찰된 반면에, 배자바깥 부위에서는 융모막과 바깥배자내배엽에서 매우 적은 수의 세포자기사 세포가 관찰되었고, 배자부위에서는 소수의 세포자기사 세포가 무작위적으로 배자외배엽과 중배엽, 그리고 배자내배엽 부위에서 관찰되었다. 체절형성기 초기 (발생 $8.0\sim8.5$일)에는 많은 수의 세포자기사 세포가 신경주름(neural fold)의 가장 앞쪽(머리쪽)에 주로 분포하는 것이 관찰되었다. 체절형성기 중기(발생 $9.0\sim9.5$일)에 귀기원판(otic placode)부위에서 처음으로 세포자기사 세포가 관찰되었고, 적은 수의 세포자기사 세포들이 또한 눈기원판(optic placode)과 아가미궁에서도 관찰되기 시작하였다. 발생 $9.5\sim9.75$일째에 크게 세가지 흐름의 세포자기사 세포들이 머리쪽 부위에서 관찰되었다. 발생 10.5일째에는 세포자기사 세포들이 발생중인 눈 부위와 안쪽코돌기와 바깥쪽코돌기 그리고 상악돌기가 만나는 부위, 아가미궁의 가쪽부위, 양쪽 하악돌기가 만나는 중앙부위, 그리고 팔다리싹의 꼭대기외배엽능선에 국한되어 관찰되었다. 발생 11.5일째에는 세포자기사 세포가 발생중인 팔다리부위와 꼬리부위를 제외한 나머지 부위에서는 현저히 감소되어 나타났다. 본 연구에서는 생쥐 발생초기 동안에 나타나는 세포자기사 세포가 발생시기에 따라 어느 부위에 발현되는 가는 알아보았는데, 이러한 연구 결과는 배자의 형태발생을 연구하는데 기초적인 자료로 활용될 수 있을 것으로 사료된다.

• Journal of Korean Neurosurgical Society
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• 제63권3호
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• pp.279-313
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• 2020

This review summarises the classification, anatomy and embryogenesis of complex spinal cord lipomas, and describes in some detail the new technique of total lipoma resection and radical reconstruction of the affected neural placode. Its specific mission is to tackle two main issues surrounding the management of complex dysraphic lipomas : whether total resection confers better long term benefits than partial resection, and whether total resection does better than conservative treatment, i.e., no surgery, for asymptomatic lipomas. Accordingly, the 24 years progression-free survival data of the author and colleagues' series of over 350 cases of total resection are compared with historical data from multiple series (including our own) of partial resection, and total resection data specifically for asymptomatic lesions are compared with the two known series of non-surgical treatment of equivalent patients. These comparisons amply support the author's recommendation of total resection for most complex lipomas, with or without symptoms. The notable exception is the asymptomatic chaotic lipoma, whose peculiar anatomical relationship with the neural tissue defies even our aggressive surgical approach, and consequently projects worse results (admittedly of small number of cases) than for the other two lipoma subtypes of dorsal and transitional lesions. Prophylactic resection of asymptomatic chaotic lipomas is therefore not currently endorsed.

• 대한수의학회지
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• 제55권3호
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• pp.181-184
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• 2015

Ciliary rootlet coiled coil protein (CROCC), the structural component that originates from the basal body at the proximal end of the ciliary rootlet, plays a crucial role in maintaining the cellular integrity of ciliated cells. In the current study, we cloned Xenopus CROCC and performed the expression analysis. The amino acid sequence of Xenopus laevis was related to those of Drosophila, cow, goat, horse, chicken, mouse and human. Reverse transcription polymerase chain reaction analysis revealed that CROCC mRNA encoding a coiled coil protein was present maternally, as well as throughout early development. In situ hybridization indicated that CROCC mRNA occurred in the animal pole of embryo during gastrulation and subsequently in the presumptive neuroectoderm at the end of gastrulation. At tailbud stages, CROCC mRNA expression was localized in the anterior roof plate of the developing brain, pharyngeal epithelium connected to gills, esophagus, olfactory placode, intestine and nephrostomes of the pronephric kidney. Our study suggests that CROCC may be responsible for control of the development of various ciliated organs.

• Clinical and Experimental Reproductive Medicine
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• 제26권2호
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• pp.281-285
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• 1999

Kallmann's syndrome has both a general and specific connotation in describing general condition of gonadotropin-releasing hormone (GnRH) deficiency or a particular cluster of anomalies associated with primary eunuchoidism. The familial occurrence of hypogonadotropic hypogonadism associated with anosmia, color blindness, synkinesia, and mental defect is the classic Kallmann's syndrome. Interestingly, anosmia, or lack of smell, was not found in the absence of gonadal deficiency in the original study of this disorder. This disorder was found on both sexes, but the male to female ratio was 11:1, and Kallmann's syndrome is more often listed under disorders of male hypogonadism for this reason. Gross anatomy has shown disorders of the olfactory bulbs associated with Kallmann's syndrome and it was demonstrated a failure of GnRH-containing cells to migrate from the olfactory placode to the hypothalamus and preoptic area. We have experienced a case of Kallmann's syndrome which showed a hypoplasia of olfactory bulb in MRI during the workup of primary amenorrheic patient. So we report this case with a brief review of literatures.

• Journal of Korean Neurosurgical Society
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• 제46권5호
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• pp.468-471
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• 2009

Objective : The adolescent presentation of tethered cord syndrome (TCS) is well-recognized, but continues to pose significant diagnostic and management controversies. The authors conducted a retrospective study of clinical outcomes after surgical intervention in 24 school-aged children, adolescents, and young adults with TCS. Methods : All 83 patients with a lipomyelomeningocele (LMMC) underwent untethering surgery for caudal cord tethering between 1987 and 2007. The clinical charts and follow-up data were reviewed. Of these patients, 24 school-aged children, adolescents, and young adults with TCS were studied with respect to the clinical, radiologic, pathologic features, and surgical outcomes. Results : Untethering procedures were performed in 24 patients (age range, 7-25 years) for TCS of various origins (lipoma, lipomyelomeningocele, and tight filum terminale). Specific circumstances involving additional tugging of the already tight conus, and direct trauma to the back precipitated the onset of symptom in 50% of the patients. Diffuse and non-dermatomal leg pain, often referred to the anorectal region, was the most common presenting symptom. Progressive sensorimotor deficits in the lower extremities, as well as bladder and bowel dysfunction, were also common findings, but progressive foot and spinal deformities were noted less frequently. The most common tethered lesions were intradural lipomas, thickened filum and fibrous band adhesions into the placode sac. The surgical outcome was gratifying in relation to pain and motor weakness, but disappointing with respect to resolution of bowel and bladder dysfunction. Of the 24 patients with TCS, pre-operative deficits improved after surgery in 14 (58.3%). remained stable in 8 (33.4%). and worsened in 2 (8.3%). Conclusion : The pathologic lesions of tethered cord syndrome in school-aged children, adolescents, and young adults, are mostly intradural lipomas and tight filum. It is suggested that the degree of cord traction results in neurologic dysfunction in late life due to abnormal tension, aggravated by trauma or repeated tugging of the conus during exercise. Early diagnosis and adequate surgical release might be the keys to the successful outcome in school-aged children, adolescents, and young adults with TCS.