(A) study on the development and growth of craniofacial complex in Korean embryo and fetus

치의학과/박사[한글] 교정학 분야에서는 두개안면부의 성장과 발육에 대한 지식이 중요하며, 대개 출생 후의 성장과 발육에 중점을 두어 이 시기에 두개안면부가 어떻게 성장 발육하는가를 연구해왔다. 체질인류학적으로 종족에 따라 두경부의 특성이 다르다는 것은 잘 알려져 있으며, 우리나라를 포함한 각 종족에서 소아 및 청소년기에 두경부의 성장 및 발육이 어떠한 특징을 나타내는가에 대한 기준치가 제시되어 있다 그러나 두개골이 초기 발생부터 두개안면부의 성장에 이르기까지 체계적으로 연구한 보고는 거의 없다. 따라서 이 연구에서는 한국인 배자 20예와 태아 38예를 대상으로 두개골이 처음 형성되어 태생기 중 어떻게 성장 발육하는가를 시기 별로 조직 표본 관찰, Alizarin Red S 염색, 컴퓨터 단층 촬영 등의 방법으로 종합 분석하고, 방사선 사진으로 두개 계측을 시도하여 소아 및 청소년기의 두개안면부의 성장과 발육을 이해하는 이론적 배경을 제공하고 나아가 실제 임상 분야에 도움이 되는 기초적 자료를 제공하고자 시도하여 다음과 같은 결과를 얻었다. 1. 두개 기저부의 원기를 나타내는 중간엽의 축합은 발생 14기에 이낭에서, 두개관에서는 모든 부위에서 발생 17기에 관찰되었다 2. 중간엽의 연골화는 발생 20기에 이낭에서 처음 시작되었다. 3. 막내골화는 하악골에서 발생 20기에, 상악골에서 발생 22기에, 전두골 안와연에서 발생 23기에 시작되었다. 4. 연골내골화는 Alizarin Red S로 염색한 발생 9주 태아 측두골 및 후두골의 일부 연골에서 시작되었다. 5. 전산 단층 촬영에서 발생 20주에 봉합들이 분명하게 관찰되었고 두개골 바닥이 점차 완성됨을 알 수 있었다. 6. 측모두부방사선을 이용한 두개계측에서 거리는 발생과 함께 증가하는 양상을 보였으며 특히 전안면고경 (Na-Sym) 및 하악골의 하전방 성장 (S-Sym)이 빠르게 증가하였다. 이상의 결과를 요약하면 발생 중 두개 기저부가 먼저 형성되기 시작하였으나 골화는 두개관에서 더 빠르게 진행되었다. 또한 카네기 발생기로 분류한 한국인 배자에서 두개골의 발생이 진행되는 시기가 대체로 외국의 다른 보고에 비해 다소 늦는 경향을 보였는데, 이것이 개체 혹은 종족에 따른 차이인지 좀 더 상세하게 구명되어야 할 것으로 생각되었다 [영문] Understanding the growth and development of craniofacial complex is important in the field of orthodontics, but usually most of studies were concentrated in post-natal growth and development. It is well known that different races have their own anthropological characteristics in head and neck region and each race, including Korean, has their own standards in head and neck growth and development during childhood and adolescents. But there is almost no report on the study throughout the initial development, skull growth and the growth of craniofacial complex. At this point, early development of the skull was investigated during embryonic and fetal period. Twenty embryos and thirty eight fetuses were analyzed by using routine histologic method, Alizarin Red S stain, computerized three-dimensional tomogram, and cephalometrics. The results are as follows; 1. The mesenchymal condensation which represents primordia of the skull base was observed around the otic vesicle in stage 14 and that of calvaria were in stage 17. 2. Transformation mesenchymal condensations to cartilage was observed around otic vesicle in stage 20. 3. Intramembraneous ossification of mandible was observed in stage 20 and maxilla in stage 22. 4. Endochondral ossification was observed in the part of temporal and occipital bone in Alizarin Red S stained 9 week fetus. 5. With computerized tomogram, sutures between skull bones were evident and beginning of ossification in the skull base was observed in 20 week fetus. 6. Linear measurement using lateral cephalogram showed high correlation with fetal aging (r>0.90). Anterior facial height (Na-Sym) and forward and downward growth of mandible (S-Sym) shows faster growth. From the above results, primordia of skull base was observed earlier than that of calvaria, but beginning and progress of ossification was reversed. Also, initial development of skull in staged Korean embryos had a tendency to develop later compare to other races. Further investigation is needed to confirm this difference is due to individual variation or racial one.restrictio

플래시메모리 기반 내장형 시스템의 파워시스템 무결성 검증기법

학위논문(석사) --서울대학교 대학원 :전기. 컴퓨터공학부,2008.2Maste

Studies on the regulation mechanisms of diverse phospholipase C isotypes

DoctorPhospholipase C (PLC) is a key enzyme in signal transduction by catalyzing the formation of inositol-1,4,5-triphosphates (IP3) and diacylglycerol (DAG) from phosphatidylinositol-4,5-bisphosphates (PIP2), which are implicated in intracellular Ca2+ mobilization and protein kinase C (PKC) activation, respectively. To date, 13 members of the mammalian PLC family have been identified and they are classified into 6 isotypes based on their primary structures : β, γ, δ, ε, ζ, and η. Although all PLC isotypes show similar enzymatic activity, they display distinct knock-out phenotypes. Given that PLC isotypes possess unique domain structures and show different tissue expression patterns, it seems likely that they are influenced by different signaling pathway to regulate different physiologic functions. Therefore, elucidating the regulation mechanisms of each PLC isotype is prerequisite to understand its physiological functions.PLC-β is a key effector in G-protein coupled receptor (GPCR)-mediated signaling. Many studies have shown that the four PLC-β subtypes (β1~β4) have different physiological functions despite their similar structures. Because the PLC-β subtypes possess different PDZ-binding motifs, they have the potential to interact with different PDZ proteins. In this study, I identified PDZ domain-containing 1 (PDZK1) as a PDZ protein that specifically interacts with PLC-β3. To elucidate the functional roles of PDZK1, I next screened for potential interacting proteins of PDZK1 and identified the somatostatin receptors (SSTRs) as another protein that interacts with PDZK1. Through these interactions, PDZK1 assembles as a ternary complex with PLC-β3 and SSTRs. Interestingly, the expression of PDZK1 and PLC-β3, but not PLC-β1, markedly potentiated SST-induced PLC activation. However, disruption of the ternary complex inhibited SST-induced PLC activation, which suggests that PDZK1-mediated complex formation is required for the specific activation of PLC-β3 by SST. Consistent with this observation, the knockdown of PDZK1 or PLC-β3, but not that of PLC-β1, significantly inhibited SST-induced intracellular Ca2+ mobilization, which further attenuated subsequent ERK1/2 phosphorylation. From these results, I strongly suggest that the formation of a complex between SSTRs, PDZK1, and PLC-β3 is essential for the specific activation of PLC-β3 and the subsequent physiologic responses by SST.PLC-η1 is the most recently identified PLC isotype and is primarily expressed in nerve tissue. However, its functional role is still unclear. In this study, I found for the first time that PLC-η1 acts as a signal amplifier in G protein-coupled receptor (GPCR)-mediated PLC/Ca2+ signaling. Short-hairpin RNA (shRNA)-mediated knockdown of endogenous PLC-η1 reduced lysophosphatidic acid (LPA)- , bradykinin (BK)- , and PACAP-induced PLC activity in mouse neuroblastoma Neuro2A (N2A) cells, indicating that PLC-η1 participates in GPCR-mediated PLC activation. Interestingly, ionomycin-induced PLC activity was significantly decreased by PLC-η1, but not PLC-η2, knockdown. In addition, I found that intracellular Ca2+ source is enough for PLC-η1 activation. Furthermore, the IP3 receptor inhibitor, 2-APB, inhibited LPA-induced PLC activation in control N2A cells, whereas this effect was not observed in PLC-η1 knockdown N2A cells, suggesting a pivotal role of intracellular Ca2+ mobilization in PLC-η1 activation. Finally, LPA-induced ERK1/2 phosphorylation and expression of the downstream target gene, krox-24, were significantly decreased by PLC-η1 knockdown and these knockdown effects were abolished by 2-APB. From these results, I strongly suggest that PLC-η1 is secondarily activated by intracellular Ca2+ mobilization from the ER and therefore amplifies GPCR-mediated PLC/Ca2+ signaling.Mast cell is responsible for IgE-mediated allergic responses through secretion of various inflammatory cytokines and mediators. Thus, pharmacological regulation of mast cell activation is significant for the development of novel anti-allergic drugs. In this study, I found that spiraeoside (SP) inhibits mast cell activation and allergic response in vivo. SP dose-dependently inhibited the degranulation induced by IgE-antigen (Ag) stimulation in RBL-2H3 mast cells without cytotoxic effect. At the molecular level, SP reduced Ag-induced phosphorylation and activation of phospholipase C-γ2 (PLC-γ2). Moreover, SP inhibited phosphosrylation of spleen tyrosine kinase (Syk), linker for activation of T cells (LAT), and downstream MAPK such as ERK1/2, p38, and JNK, which eventually attenuated expression of TNF-α and IL-4. Finally, I found that SP significantly inhibited IgE-mediated passive cutaneous anaphylaxis (PCA) in mice. From these results, I strongly suggest that SP suppresses IgE-mediated mast cell activation and allergic response by primarily inhibiting Lyn-induced PLC-γ2 / MAPK signaling in mast cell

Possible role of PLC eta1 as a downstream amplifer in GPCR-mediated signaling

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CLAMP regulates PLC-beta3 specific activation of somatostatin via forming a ternary complex with PLC-beta3 and somatostatin receptor

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Possible role of PLC-n as a downstream amplifier of GPCR- mediated signaling

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