플라티코딘 D와 효소에 의해 전환된 플라티코딘 D 강화분획물의 지방축척 억제효과

학위논문 (박사)-- 서울대학교 대학원 : 약학대학 약학과, 2019. 2. 김영식.길경 (Platycodon grandiflorum A. DC)의 유효성분이자 지표성분인 플라티코딘 D는 기존에 항암, 항산화, 항염증 등의 효능이 있는 것으로 보고가 되고 있다. 최근, 플라디코딘 D는 동물모델에서 지질대사 관련 개선능과 항비만 생리활성이 탁월한 것으로 많은 보고가 있었음에도 불구하고, 아직까지 세포수준에서 어떠한 기전으로 항비만 효과가 있는지 명확한 결과는 없고, 세포수준의 결과가 동물실험 상에서 동일하게 재현되지 않은 단점이 있다. 본 연구에서는 지방합성에 관여하는 peroxisome proliferator-activated receptor γ2 (PPARγ2)와 지방세포분화에 관여하는 mitogen activated protein kinase (MAPKs), 지방산화에 중추적 역할을 하는 AMP-activated protein kinaseα(AMPKα)의 활성을 측정하여, 지방세포에서 플라디코딘 D의 지방축척억제 효과를 확인하고 지방유도동물 모델에서 지방 억제 효과를 보고자 하였다. 플라디코딘 D가 탁월한 약리학적 가치를 가지고 있긴 하지만, 도라지 건조 중량의 미량으로 포함 되어 있고, 기존의 천연물분리 방법으로는 시간이 오래 걸리고, 수율이 낮은 단점이 있어서 플라디코딘 D를 상업적을 이용하는데 많은 어려움이 있었다. 본 실험실에서는 길경사포닌 중에 플라디코딘 D와 비슷한 화학 구조를 가진 플라디코딘 D유도체들을 효소처리를 하여 단시간 내에 플라디코딘 D로 전환, 플라디코딘 D의 함량을 높인 강화분획조성물을 만든 바 있다. 본 연구에서는 기존에 분리가 쉽지가 않던 플라디코딘 D를 대체하여 분리가 효율적이며 상업적 으로 이용가능성이 있는 플라티코딘 D 강화분획물 (PScell)의 지방축척 억제효과 를 확인하고자 하였다. 분화된 지방세포에 플라디코딘 D 5 μM을 처리하였을 경우 지방합성 마커인 PPARγ2와 C/EBPα가 뚜렸하게 억제되었고, 비만전사인자 (adipogenic transcription factor)인 AP2, FAS발현이 감소가 됨으로써 분화된 지방세포 내에 지방함량이 약 62.5% 정도 억제됨이 확인되었다. 또한, 지방세포 초기분화에 관여하는 것으로 알려진 유사분열 활성화 단백질 인산화효소 (MAPKkinase)는 플라디코딘 D 처리한 그룹에서 3 시간부터 24 시간까지 p-ERK를 꾸준히 억제 되었다. AMPK activator로 잘 알려진 aminoimidazole carboxamide ribonucleo- tide (AICAR)와 비교실험에서 플라디코딘 D 5 μM투여는 AICAR 1 mM 투여 보다 PPARγ2와 C/EBPα의 발현을 현저하게 억제되었고, p-AMPK와 p-ACC 발현은 유의성 있게 증가되었지만 AICAR보다는 약함이 확인되었다. 위 세포실험의 결과를 토대로, 본 실험자는 8주 동안 고지방 식이로 섭취한 C57BL/6 마우스에서 플라디코딘 D의 항비만효과를 수행하였다. 플라디코딘 D 투여그룹은 고지방식이그룹보다 경구투여 10일 이후 부터 체중이 유의성 있게 감소되었고, 실험 종료 후 고지방식이그룹보다 약 16 g정도 감소된 것으로 확인되었다. 섭취량은 투여 초기 4주 동안 유의성 있게 감소되었으나 이후 4주 투여에서는 복원됨으로써 다른 그룹간 섭취량에 차이가 없었다. 플라티코딘 D 투여 그룹에서 단위 면적당 지방의 부피와 지방세포 크기가 줄어들었고, 혈액내의 지질대사 개선 효과가 현저히 나타났다. 비만동물모델 지방조직에서 지방형성 (lipogenesis)의 표적 단백질인 PPARγ2와 C/EBPα의 발현정도가 억제되었고 AMPK 및 ACC의 발현이 증가되었으며, 간조직 또한 지방간의 핵심 마커인 sterol-regulatory element binding proteins 1 (SREBP-1)발현이 감소되었다. 뒤이어, 효소전환에 의해 플라디코딘 D가 강화된 분획물 (PScell)의 지방축척효과를 확인하였다. 플라티코딘 D 강화분획물을 지방세포분화 유도물질과 함께 농도별 (5, 7.5, 10 ㎍/㎖)로 처리한 결과, 분화된 지방세포에서 지방 축적이 농도별로 억제되었다. 8주간 진행된 동물실험에서 플라티코딘 D 강화분획물을 경구투여한 그룹에서는 고지방그룹보다 유의적인 체중감소와 복부지방량 감소 효과를 나타내었는데, 이것은 수치상 플라디코딘 D 와 약리활성수준이 비슷하거나 좀더 좋은 효능을 보일 것으로 예상되었다. 본 연구 결과들을 종합하여 볼 때, 플라디코딘 D와 플라디코딘 D 강화분획물은 비만 및 비만에 의해 유래된 지방간에 효과적인 약물일 것이라 기대된다. 또한, 플라디코딘 D 강화분획물은 그동안 상업화하기 어려웠던 플라디코딘 D의 대체물질이 될 수 있을 것이라 판단하지만, 산업화 과정에서는 단백질수준에서 기존 상품화 되어 있는 단일화합물이나 플라디코딘 D와 효능평가를 비교하는 후속실험이 필요할 것으로 사료된다.Platycodi Radix, the root of Platycodon grandiflorum (Jacq.) A. DC. (Campanulaceae), is traditionally used as a treatment for respiratory discomfort by practitioners of Traditional Chinese medicine, Japanese Kampo medicine and Korean medicine. Platycosides, the saponins found in the roots of Platycodon grandiflorum (Jacq.) A. DC. (Platycodi Radix), are typically composed of oleanane backbones with two side chains, one is a 3-O-glucose side chain linked by a glycosidic bond and the other being a 28-O-arabinose-rhamnose-xylose-apiose side chain joined by an ester bond. Platycodi Radix is known to have more than 20 saponins with similar structures. Among them, platycodin D is superior to other saponins and the distinctive compound found only in Platycodi Radix. It is known to be effective for those with a sore throat, bronchitis, cold, diabetes, inflammation and cancer. Although platycodin D has broad pharmacological value, because the total content of saponins is as low as 2% by dry weight of Platycodi Radix, it is difficult to isolate platycodin D from Platycodi Radix on a large scale. When attempting to overcome this disadvantage, we successfully isolated platycodin D in Platycodi Radix and several derivatives in a short period of time using a multi-step process which includes high-speed counter-current chromatography (HSCCC) and preparative reversed-phase high-performance liquid chromatography (HPLC) steps. We also successfully developed an enzyme-conversion technique through which platycodin D3 (PD3) and platycoside E (PE), which have two and three glucose units at C-3, respectively, are converted to platycodin D, consequently increasing the amount of platycodin D in saponin and thus making it an enriched fraction (henceforth PScell). In this study, we aim to determine the mechanism of how platycodin D, which is widely known to be effective on the bronchus, works on obesity. A second goal is to determine the effects of PScell on obesity. We initially examined platycodin D and platycodin D derivatives to determine how they inhibit lipid accumulation activity, finding that platycodin D is a more effective inhibitor than any of the platycodin D derivatives. To determine the optimal concentration of platycodin D, various doses were exposed to cells during MDI (isobutylmethylxanthine, dexamethasone and insulin)-induced differentiation. On day 8, the lipid contents in 3T3-L1 cytoplasm were measured by Oil Red O staining. The results showed that platycodin D (1, 2.5, 5 μM) blocked adipocyte differentiation in proportion to the platycodin D dose with platycodin D 5 μM inhibiting lipid accumulation in the cytoplasm by as much as 62.5% in a MDI-treated positive control without affecting cell viability. It was also found that platycodin D significantly inhibits fat accumulation of lipid droplets in the cytoplasm by inhibiting adipogenic-specific transcription factors PPARγ2 and C/EBPα in MDI-induced 3T3-L1 cells in a dose-dependent manner. Similarly, platycodin D inhibits adipocyte differentiation of 3T3-L1 cells through the ERK pathway within 24 hrs. Furthermore, we investigated the molecular mechanism of platycodin D, focusing on its ability to decrease the expression of adipogenic factors through AMP-activated protein kinase α (AMPKα) in adipocytes and to prevent abdominal fat accumulation in high-fat-diet-induced obesity among C57BL/6 mice. To verify the anti-obesity effect in vivo, a group of mice ate a normal diet while the others were fed a high-fat diet for eight weeks. The high-fat-diet mice were then divided into three subgroups: termed the aminoimidazole carboxamide ribonucleotide (AICAR) group, the vehicle group and the platycodin D group. It was found that platycodin D significantly reduced fat accumulation by inhibiting adipogenic signal transcriptional factors, in this case peroxisome proliferator-activated receptor γ2 (PPARγ2) and CCAAT/enhancer binding protein α (C/EBPα), through AMPK in vivo. Platycodin D also reduced both the body weight and fat mass and consequently improved lipid metabolism by increasing AMPK, as also seen in AICAR group, while also reducing PPARγ2 and C/EBPα expression levels in adipose tissue. In addition, glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels, which are used as indicators of hepatic disease in serum and the size of lipid drops during morphometric observations of fatty liver were significantly reduced in the platycodin D group. Moreover, protein expressions of AMP-activated protein kinase α (AMPKα) increased while sterol regulatory element binding protein-1 (SREBP-1) decreased in the platycodin D group compared to those of the high-fat group (HF). This outcome suggests that platycodin D can be used to inhibit lipid accumulation by reducing the expression levels of adipogenic factors related to the AMPK pathway and that it can be expected to improve lipid metabolism in obesity-associated hepatic lipogenesis. In addition, we attempted to investigate the fat accumulation effect of PScell, the fraction with an increased platycodin D content, by enzymatic transformation. Treatment of 3T3-L1 adipocytes with PScell (5, 7.5, 10 μg/mL) reduced lipid accumulation in a dose-dependent manner. In a mouse model, oral administration of PScell (70 mg/kg, 6 mL/kg) reduced high-fat-diet-induced body weight gain. Consistently, PScell alleviated total cholesterol, LDL cholesterol, triglyceride and glucose levels in mice serum. Liver and abdominal adipose tissues from the groups treated with PScell exhibited a decreased number of lipid droplets relative to the high-fat control group. PScell showed a stronger inhibitory effect on lipid accumulation at a slightly lower concentration than that of platycodin D numerically in in vitro and in vivo. From these results, we considered that PScell is a potential candidate as a treatment for obesity and fatty liver induced by a high-fat diet by replacing platycodin D with a low yield in Platycodi radix.CONTENTS ABSTRACT CONTENTS LIST OF FIGURES LIST OF TABLE I. INTRODUCTION 1. Platycodi Radix, Platicosides and Platycodin D 2. Adipocyte and adipogenesis 3. AMPK 4. Purpose of the study II. MATERIALS and METHODS 1. MATERIALS 1.1. Plant material 1.2. Chemicals and reagents 1.3. Cells culture 1.4. Animals 1.5. Apparatuses 2. METHODS 2.1. Preparation of crude sample 2.2. One-step separation of platycodin D by HSCCC 2.3. Sample preparation of enriched saponin fraction 2.4. Cell viability assay 2.5. Adipocyte differentiation and treatment 2.6. Oil Red O staining 2.7. Western blotting 2.8. Real time PCR 2.9. High fat diet induced obese mice 2.10. Serum analysis 2.11. Micro-computed tomography 2.12. Histological analysis 2.13. Data analysis III. RESULTS 3.1. Lipid accumulation inhibition activities of platycodin D and platycodin D derivatives isolated by HSCCC 3.2. Effects of platycodin D on lipid accumulation during adipocyte differentiation 3.3. Effects of platycodin D on the expression of p-ERK during adipocyte differentiation 3.4. Effects of platycodin D on the expression of a p-AMPKα pathway in 3T3-L1 cell 3.5. Effect of platycodin D on body weight, food intake and daily energy in high fat diet mice 3.6. Effect of platycodin D on white adipose tissue mass and serum profiles in high fat diet mice 3.7. Effect of platycodin D on adipogenic protein expression in high fat diet mice 3.8. Effects of platycodin D on lipid accumulation in liver of C57BL/6 model induced obesity 3.9. Effects of PScell on lipid accumulation inhibition activities during adipocyte differentiation 3.10. Effects of PScell on food intake, body weight gain in C57BL/6 model induced obesity 3.11. Effects of PScell on white adipose tissue and liver fatty droplet accumulation in C57BL/6 model-induced obesity 3.12. Effects of PScell on serum profiles in C57BL/6 model-induced obesity IV. DISCUSSION V. REFERENCES VI. ABSTRACT IN KOREAN VII. ACKNOWLEGEMENT LIST OF FIGURES Fig. 1. Structure of platycodin D Fig. 2. Physiological balance between hypertrophy and hyperplasia Fig. 3. Constitute of cells in white adipose tissue Fig. 4. Secretion adipokines of triglyceride overload hypertrophy adipocyte Fig. 5. Transcriptional factors of adipocyte differentiation PPARγ2, C/EBPα Fig. 6. MAPKs signal transduction pathways Fig. 7. Involvement of the MAPKs at the various steps of adipogenesis Fig. 8. Sampling-preparative isolation platycodin D from Platycodon grandiflorum A. DC. by HSCCC coupled with ELSD Fig. 9. Enzymetic biotransformation of the saponin-enriched fraction to platycodin D by cellulase Fig. 10. Large-scale modification of the saponin-enriched fraction for platycodin D Fig. 11. Adipocyte differentiation and treatment Fig. 12. High fat diet animal model experiments Fig. 13. Cytotoxicity and lipid accumulation inhibition activities of platycodin D and platycodin D derivatives Fig. 14. Effects of platycodin D on lipid accumulation during adipocyte differentiation Fig. 15. Effects of platycodin D on the expression of p-ERK during adipocyte differentiation Fig. 16. Effects of platycodin D on the activation of AMPKα during adipocyte differentiation Fig. 17. Effects of platycodin D on body weight gain, food intake and daily energy in C57BL/6 model-induced obesity Fig. 18. Effects of platycodin D on fat size, mass and serum profiles in C57BL/6 model-induced obesity Fig. 19. Effects of platycodin D on the expression of proteins related to lipid metabolism in white adipose tissue Fig. 20. Effects of platycodin D on lipid accumulation in liver of C57BL/6 model-induced obesity Fig. 21. Effects of PScell on lipid accumulation inhibition activities during adipocyte differentiation Fig. 22. Effects of PScell on food intake and body weight gain in C57BL/6 model-induced obesity Fig. 23. Effects of PScell on liver and white adipose tissue size fatty droplet accumulation in C57BL/6 model-induced obesity Fig. 24. Effects of PScell on serum profiles in C57BL/6 model-induced obesity LIST OF TABLE Table 1. The structures of various platycosidesDocto

Meta-Analysis of Expression Profiling Data Indicates Need for Combinatorial Biomarkers in Pediatric Ulcerative Colitis

Background. Unbiased studies using different genome-wide methods have identified a great number of candidate biomarkers for diagnosis and treatment response in pediatric ulcerative colitis (UC). However, clinical translation has been proven difficult. Here, we hypothesized that one reason could be differences between inflammatory responses in an inflamed gut and in peripheral blood cells. Methods. We performed meta-analysis of gene expression microarray data from intestinal biopsies and whole blood cells (WBC) from pediatric patients with UC and healthy controls in order to identify overlapping pathways, predicted upstream regulators, and potential biomarkers. Results. Analyses of profiling datasets from colonic biopsies showed good agreement between different studies regarding pathways and predicted upstream regulators. The most activated predicted upstream regulators included TNF, which is known to have a key pathogenic and therapeutic role in pediatric UC. Despite this, the expression levels of TNF were increased in neither colonic biopsies nor WBC. A potential explanation was increased expression of TNFR2, one of the membrane-bound receptors of TNF in the inflamed colon. Further analyses showed a similar pattern of complex relations between the expression levels of the regulators and their receptors. We also found limited overlap between pathways and predicted upstream regulators in colonic biopsies and WBC. An extended search including all differentially expressed genes that overlapped between colonic biopsies and WBC only resulted in identification of three potential biomarkers involved in the regulation of intestinal inflammation. However, two had been previously proposed in adult inflammatory bowel diseases (IBD), namely, MMP9 and PROK2. Conclusions. Our findings indicate that biomarker identification in pediatric UC is complicated by the involvement of multiple pathways, each of which includes many different types of genes in the blood or inflamed intestine. Therefore, further studies for identification of combinatorial biomarkers are warranted. Our study may provide candidate biomarkers for such studies.ope

TRPV1 의 비만 및 렙틴/인슐린 저항성에의 역할과 그 작용기작 규명

학위논문 (박사)-- 서울대학교 대학원 : 농생명공학부(바이오모듈레이션전공), 2014. 2. 이형주.According to prevalence of obesity and its-associated metabolic disorders worldwide, these diseases become severe and global health problem. Obesity defined as a condition accumulated excess fat mass bodily is a hall marker and major cause of metabolic diseases such as cardiovascular disease, stroke, and type 2 diabetes (T2D). Because obesity and T2D patients have dramatically higher risks of cardiovascular disease, the most common cause of death in Western countries, an increase in the prevalence of obesity and diabetes in the population is one of the most serious problems of modern society. Thus, the prevention and treatment of obesity and T2D become more and more important. Insulin resistance, an attenuated or lack of response of the insulin receptor (IR) and its downstream signaling pathway to insulin stimulation even at high doses of insulin, is a representative characteristic of T2D. Although insulin resistance is caused by inflammation, oxidative stress, ER stress, and mitochondrial dysfunction, the specific mechanisms which lead from obesity to T2D is still unclear. Recent evidences have been clearly showed that capsaicin, a pungent component of chili peppers, play a crucial role in obesity and metabolic disorders. Administration of capsaicin prevents obesity and improves glucose homeostasis and insulin secretion in small rodents and humans. Several previous studies have reported supportive clinical evidence that consumption of red peppers or capsaicin was shown to decrease appetite, cause weight loss and stimulate thermogenesis caused by substrate oxidation from carbohydrate to fat oxidation. However, the role of its receptor, transient receptor potential vanilloid subfamily type 1 (TRPV1), in development of obesity and its- associated insulin resistance is controversial, which suggests that its specific function and mechanistic studies in metabolic disorders are poorly understood. Here, I examined the effect of TRPV1, capsaicin receptor, on diet-induced obesity and insulin resistance in mice. TRPV1-deficient mice became more obese and get more fat accumulation on high-fat diet (HFD) feeding than wild-type (WT) mice. These results were caused by reduced locomotor activity in TRPV1 KO mice fed HFD for 5 weeks. In TRPV1 KO mice, plasma leptin levels were decreased. Although leptin up-regulates locomotor activity as well as energy expenditure, TRPV1 KO mice showed decreased activity and no changes in energy expenditure compared to WT mice, suggesting severe leptin resistance in TRPV1 KO mice fed HFD. All of these results indicated that TRPV1 is a regulator of energy balance and development of leptin resistance in obese mice. In addition, TRPV1 deletion accelerates diet-induced insulin resistance. Insulin-stimulated glucose uptake in adipose tissues and heart was significantly diminished in HFD-fed TRPV1 KO mice. As one of the major causes of inflammation, oxidative stress and mitochondrial dysfunction, aging has been showed to induce obesity and insulin resistance. Deletion of TRPV1 in mice accelerated aging-induced weight gain and insulin resistance. Unlike the results fed HFD, aging promoted hepatic insulin resistance in TRPV1 KO mice compared to WT mice. Thus, these results provide new insight into the involvement of TRPV1 in development of obesity and insulin resistance and promising strategy against their pathogenesis.Contents Abstract i Contents v Chapter 1. Metabolic syndrome, transient receptor potential vanilloid subfamily type 1, and its agonists in food: A Review 1 Abstract 2 1.1. Introduction 4 1.2. Development of metabolic diseases 6 1.2.1. Obesity 6 1.2.2. Hyperglycemia, insulin resistance and type 2 diabetes 7 1.2.3. Hyperlipidemia, hyperleptinemia and Leptin resistance 9 1.3. Molecular mechanisms of TRPV1 and capsaicin in metabolic disease 14 1.3.1. Capsaicin receptor: Transient receptor potential vanilloid subfamily type 1 14 1.3.2. In obesity : adipogenesis and thermogenesis 15 1.3.3. In diabetes mellitus: insulin secretion and resistance 18 1.4. Conclusions 19 1.5. References 20 Chapter 2. TRPV1 is a regulator of energy homeostasis and leptin resistance 30 Abstract 31 2.1. Introduction 33 2.2. Materials and Methods 36 2.2.1. Animals 36 2.2.2. Body composition and energy balance measurement 36 2.2.3. Leptin/adiponectin ELISA assay 37 2.2.4. Leptin infusion study 37 2.2.5. Leptin signaling in primary cultured mouse embryonic fibloblasts (MEFs) 38 2.2.6. Leptin stimulation study 38 2.2.7. Western blotting 39 2.2.8. Statistical analysis 40 2.3. Results 41 2.3.1. Deletion of TRPV1 induces higher accumulation of fat and obesity during HFD feeding 41 2.3.2. TRPV1-deficient mice decreases locomoter activity 41 2.3.3. Deletion of TRPV1 induces increased plasma leptin levels compared to WT mice after HFD 43 2.3.4. Negative correlation between leptin and physical activity/energy expenditure in TRPV1 KO mice fed HFD 46 2.3.5. Impaired TRPV1 channel promotes leptin resistance in mice fed HFD 48 2.3.6. Deletion of TRPV1 induces blunted leptin signaling in MEFs and mice 51 2.4 Discussion 57 2.5. References 59 Chapter 3. TRPV1 deficiency deteriorates diet-induced obesity and insulin resistance in mice 70 Abstract 71 3.1. Introduction 72 3.2.Materials and methods 75 3.2.1. Animals. 75 3.2.2. Body composition 75 3.2.3. Hyperinsulinemic-euglycemic clamp 75 3.2.4. Biochecmical analysis and calculation 76 3.2.5. Plasma insulin measurement 77 3.2.6. Glucose uptake assay 78 3.2.7. Western blotting 78 3.2.8. Statistical analysis 79 3.3. Results 80 3.3.1. HFD-induced obesity and insulin resistance are worsed by deletion of TRPV1 80 3.3.2. Deletion of TRPV1 did not affect on impared insulin action in liver and skeletal muscle 82 3.3.3. Deletion of TRPV1 reduces glucose uptake into adipose tissues and heart 84 3.3.4. TRPV1 deficiency induces impaired insulin signaling in WAT after HFD feeding in mice 86 3.4. Discussion 91 3.5. References 94 Chapter 4. Deficiency of TRPV1 accelerates aging-induced obesity and insulin resistance in vivo 99 Abstract 100 4.1. Introduction 102 4.2.Materials and methods 105 4.2.1. Animals 105 4.2.2. Body composition 105 4.2.3. Energy balance measurement 105 4.2.4. Hyperinsulinemic-euglycemic clamp 106 4.2.5. Biochemical analysis and calculation 107 4.2.6. Glucose uptake assay 108 4.2.7. Statistical analysis 108 4.3. Results 109 4.3.1. TRPV1-deficiency accelerates aging-induced obesity in mice 109 4.3.2. TRPV1-deletion reduces energy expenditure 109 4.3.3. Deletion of TRPV1 promotes aging-induced insulin resistance 113 4.3.4. Deletion of TRPV1 aggrevates aging-induced impaired insulin sensitivity in liver 116 4.3.5. Deletion of TRPV1 have no effect on glucose uptake levels in adipose tissues, muscle, and heart 116 4.4. Discussion 120 4.5. References 123 Chapter 5. Conclusions 127 5.1 Deterioration of diet-induced obesity and leptin resistance in TRPV1 deficient mice 128 5.2 Deterioration of diet- and aging-induced obesity and insulin resistance in TRPV1 deficient mice 130 5.3 Discussion 132 5.4 References 137 국문초록 140 Acknowledgement 143Docto

수학교사의 실천적 지식 구성 과정에 대한 연구

학위논문 (박사)-- 서울대학교 대학원 : 수학교육과, 2015. 2. 이경화.본 연구는 수학교사 교육에서 교사의 실천적 지식의 중요성이 점차 강조되고 있으나, 실천적 지식의 의미와 구성 방법에 대한 논의가 부족하다는 문제의식에서 출발하였다. 특히, 수학교사의 실천적 지식 구성을 위한 구체적인 방법에 대한 논의가 이루어지기 위해서는 교사의 실천에 반드시 수반되는 암묵적 지식에 대한 분석이 선행되어야 함에 주목하였다. 이에 본 연구에서는 문헌 분석을 통해 교사의 실천에 관여하는 다양한 지식과 더불어 암묵적 지식의 의미를 면밀히 파악하였다. 교수학적 내용지식, 수학을 가르치기 위한 지식 등 분절적으로 수학교사의 전문적 지식에 대해 이루어진 기존의 논의에, 수학교사의 실천을 둘러싼 암묵적 차원에 대한 연구를 보완함으로써 수학교사의 실천적 지식의 의미를 구체화하였으며, 실제 수학교사의 실천적 지식 구성 과정을 확인하기 위하여 과제 설계에서부터 수업 실행에 이르는 일련의 과정을 분석하였다. 폴라니의 인식론에 근거하여 암묵적 지식의 의미를 살펴본 결과는 다음과 같다. 먼저 암묵적 지식은 삼원적 구조로 이루어지며, 인식자, 보조식, 초점식이 그 세 요소이다. 인식자는 보조식의 세목들이 무엇인지 정확하게 식별할 수는 없지만 그것들을 제어할 수 있다. 또, 인식자는 특정한 목적과 의도를 가지고 의식하는 초점 대상에 보조식의 세목들을 관련시킬 수 있다. 이 과정에 의하여 초점식과 보조식이 교대되면서 기술과 지식이 발달한다. 이와 같은 관점에 비추어보면, 교사는 자신의 신념과 같은 암묵적 지식과 무의식적으로 행하는 교수 활동을 반성하고 의식화하고, 의식적으로 교수 행위를 하면서 다시 무의식적으로 행하게 되는 과정을 통해 실천적 지식을 구성하고 발달시켜나간다고 볼 수 있다. 요컨대, 교사의 실천적 지식은 명시적 차원과 암묵적 차원이 존재하며, 교사가 암묵적 차원의 작용을 인식하고 이를 성찰하는 것은 교사의 실천적 지식 구성 과정에서 매우 중요하다는 점을 확인하였다. 교사의 식(awareness)은 교사의 지식과 더불어 주관적인 경험과 관련이 있다. 실제 수업 상황에서의 교사의 식(awareness)은 교사의 의도와 목적에 따라 주관적인 경험을 통해 형성된 감각과 상황으로부터의 단서가 교사의 지식과 결합되어 세부적인 사항들을 지각함으로써 교사의 행동으로 드러나게 된다. 적절하고 합리적인 방식으로 수업을 실행하기 위해서, 교사는 수업에서 중요하게 다루어져야 할 측면들에 의도적이고 의식적으로 주의를 기울이고 지속적으로 관찰하면서 수업에서 발생하는 사건들의 미묘한 차이들을 알아차리고 이에 적절한 대응을 경험해나가면서 그 상황에 대한 식(awareness)을 키워나갈 필요가 있다. 교사의 식(awareness)에 대한 논의로부터 도출한 시사점은 교사가 자신의 교수 활동을 의식화함으로써 자신의 행동 이면에 존재하는 암묵적 차원이 수업과 학생의 학습에 중요한 영향을 미치고 있다는 것을 깨닫게 되면서 실천적 지식을 구성할 수 있다는 것이다. 실천적 지식에 대한 선행연구와 암묵적 지식에 대한 논의를 토대로, 수학교사의 실천적 지식 구성을 위해서는 교사의 실천 경험, 이론적 지식 그리고 교사의 식(awareness)의 세 요소가 필요함을 확인하였다. 또한 교사의 식(awareness)을 강화시키기 위한 전략으로 교사의 반성과 알아차림(noticing)을 제안하였다. 알아차림은 체계적인 반성을 기반으로 교사의 민감성을 키울 수 있기 때문에 교사의 식(awareness)을 강화시키고 경험과 명시적인 지식이 조화롭게 균형을 이루는데 효과적인 방법이 될 수 있다. 수학교사의 실천적 지식 구성을 위한 세 요소와 반성과 알아차림 전략을 토대로 교사교육의 절차를 다음과 같은 다섯 단계로 설계하였다. 이론학습, 과제설계, 사고실험, 수업실행, 수업에 대한 분석이 그것이다. 본 연구에서는 중학교 교사가 이 절차에 따라 실천적 지식을 구성하는 과정에 대하여 살펴보았다. 연구 결과, 실천적 지식의 구성 과정은 크게 초점식화와 보조식화로 이루어진다는 것을 알 수 있었다. 초점식화 과정에서 교사는 암묵적 차원의 보조식들을 의식화하고 반성함으로써 실천을 변화시키려는 의지를 가지고 의식적인 교수 활동을 해가면서 실천을 개선한다. 이어서 보조식화 과정에서 다시 무의식적인 교수 활동을 하게 된다. 본 연구에 참여한 교사는 의식화와 반성에 의한 초점식화 그리고 이를 다시 보조식화 과정을 교대로 거치면서 실천적 지식을 구성하였다. 그러나 변화된 교수 활동이 습관화되어 안정적으로 교사의 암묵적 차원으로 자리 잡기 위해서는 장시간이 필요하기 때문에 이에 대해서는 향후 추적 관찰이 필요할 것으로 보인다. 본 연구에서는 암묵적 지식에 대한 면밀한 분석을 통해 실천적 지식의 의미를 구체적으로 밝히고 이를 토대로 실천적 지식 구성을 지원하는 절차를 제안하였다. 또한, 중학교 수학교사가 이 절차에 따라 실천적 지식을 구성하는 과정에 대하여 살펴봄으로써 실천적 지식에 관한 이론적이고 실제적인 접근을 시도하였다. 실천적 지식은 그 특성이 다면적이고 모호하여 다루는 것이 쉽지 않다. 그러나 실천적 지식은 수학교사의 전문성을 이루는 핵심적인 요소이므로 다각도로 이해하고 분석하여 그 특성을 밝히고 구성 방안을 모색할 필요가 있다.CHAPTER Ⅰ. INTRODUCTION 1 1. Background on the study 1 2. Research questions 10 3. Outline of the study 11 CHAPTER Ⅱ. TACIT KNOWLEDGE 13 1. The meaning of tacit knowledge 14 2. The structure of tacit knowing and construction of knowledge 18 3. Tacit knowing and teaching 25 3.1. Tacit knowing and awareness 30 3.1.1. Awareness and noticing 32 3.1.2. Importance of mathematics teacher awareness 38 3.2. Tacit knowledge and socio-cultural environment 40 CHAPTER Ⅲ. CONSTRUCTION OF MATHEMATICS TEACHERS PRACTICAL KNOWLEDGE 48 1. The concept of mathematics teachers practical knowledge and its components 48 2. Strategies for the reinforcement of mathematics teacher awareness 54 2.1. Reflection 55 2.1.1. Process of reflection 56 2.1.2. Content of reflection 58 2.2. Noticing 60 3. Teacher training procedures for the construction of mathematics teachers practical knowledge 65 3.1. Learning theory 65 3.2. Task design 67 3.3. Thought experiment 73 3.4. Conduct of class 78 3.5. Analysis of class with colleagues 79 CHAPTER Ⅳ. THE CONDUCT OF RESEARCH 81 1. Method 82 1.1. Research participants 82 1.2. Data gathering process 84 1.3. Analysis of data 88 2. Task design on similarity of figures and teachers noticing in thought experiment 90 2.1. Purpose of task design 90 2.2. Noticing during the task design and thought experiment 92 3. Noticing and reflection in class 102 3.1. When noticing from thought experiment is reflected 103 3.1.1. Inducing understanding of similarity concept by systematically proposing examples 103 3.1.2. Recognizing the concept of similarity that exists behind diverse methods 117 3.1.3. Expansion of perspective through utilization of mathematical tool 121 3.2. A case in which the noticing from thought experiment is not well-reflected 133 3.2.1. A case in which the noticing at mathematical dimension does not lead to psychological and management of teaching dimensions 133 3.2.1.1. Unable to accurately identify the students level of understanding 133 3.2.1.2. The interaction with the students is not adequate 138 3.2.2. The case in which the previous way of teaching appears 142 3.2.2.1. Unable to provide enough opportunities to inquiry 142 3.2.2.2. The teacher asks dichotomy or short-answer questions 146 4. Noticing and reflection from class analysis 150 4.1. Recognition of the necessity to understand the students 150 4.2. Recognition of the teachers orientation 153 4.3. Teachers recognition of her purpose 156 5. Discussion 158 CHAPTER Ⅴ. SUMMARY AND DISCUSSION 166Docto

전분식품의 치아우식유발력에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 치의학과, 2016. 8. 진보형.Starch is a common source of fermentable carbohydrates. It's slow absorption and degradation make it superior among other low molecular carbohydrates. Yet, current studies reflect incoherent claims about the cariogenic potentiality of starch. An evaluation analyzing the correlation of microbial and various physiochemical factors and demineralized quantity (radioisotope 32P) which was recently developed and introduced using polyacrylamide hydroxyapatite disc (PAHA) was performed through 11 starchy foods to determine the cariogenic potentiality in vitro affecting dental caries. Test subjects (11 starchy foods) were treated and prepared specified by a modified method from the Association Official Analytical Chemists (AOAC). Subjects included total 5 group of 11 starchy foods, measured both physiochemical & microbial factorsmoisture content, total starch, hydrolyzed starch, pH, titratable acidity, total sugar, reducing sugar, texture, and total viable cell count after inoculation of S.mutans and demineralized quantification and degree of radioisotope 32P using PAHAliquid scintillation count, scanning electronic microscopy and confocal laser scanning microscopy. Pearson correlation and stepwise regression were performed as a statistical evaluation to analyze the caries-associated variable by SPSS software for Windows (version 23.0, SPSS Inc., Chicago, IL, USA) and IBM Watson Analytics (cognitive analytics). The total average of moisture content, starch, hydrolyzed starch, pH, titratable acidity, total sugar, reducing sugar, TPA (hardness, springiness, cohesiveness, chewiness and adhesiveness) and total viable cells after inoculation of S. mutans in 11 test foods were 32.3%, 67.4%, 9.3%, 5.8, 0.38%, 245.1 mg/g, 17.5 mg/g, 2409.0, 0.57, 0.43, 621.5, -38.8 and 2.22 × 106/ml. With Pearson correlation coefficients (r) of caries-associated variables, including total starch, hydrolyzed starch, titratable acidity, reducing sugar and TPA results, including hardness, cohesiveness, chewiness, adhesiveness were significant at p < 0.001 and pH, total sugar and springiness (TPA) presented p < 0.05 significance. Hydrolyzed starch, adhesiveness, total viable cells of S. mutans, moisture content and titratable acidity affected cariogenic potentiality significant at p < 0.001, reducing sugar presented p < 0.01 significance, springiness significant at p < 0.05 and an adjusted R² at 0.904 showed p < 0.05 significance, analyzing caries-associated variable factors by stepwise regression analysis. Caries associated multivariate analysis was authorized to assess cariogenic potential of starchy foods. Through statistical validation, quantifying demineralization in vitro by measuring radioisotope ³²P released from PAHA disc model showed a significance with other physiochemical factors. With PAHA, this study managed to quantify the starch-induced demineralization in vitro. While the method holds limited information than in situ or in vivo model in terms of providing oral physiological process, it standardized the various types, proportion and characteristics of both individual or bovine models and the PAHA disc was the best candidate. As a standardized matter, which is commonly totaled as enamel compound due to chemical resemblance, it clearly presented a reliability and reproducibility throughout the research. Finally, this data was contributed to the national oral health to mark the cariogenic potential index in starchy foods.Literature Review 1 I. Starch 3 II. Cariogenic Potential of Starch 5 III. Methods for Assessment of Cariogenicity 8 1. Introduction 11 2. Material & Method 14 2.1 Materials 14 2.1.1 Foods 14 2.1.2 Artificial Saliva 14 2.1.3 Strain 15 2.1.4 Hydroxyapatite Disc 15 2.2 Methods 16 2.2.1 Preparation of the Foods 16 2.2.2 Physico-chemical Factors 16 2.2.3 Microbial Factor 21 2.2.4 Radioisotope-labeled PAHA Disc 22 2.2.5 Statistical Analysis 24 3 Results 25 3.1 Physico-chemical Factors 25 3.1.1 Starch 25 3.1.2 pH and Titratable Acidity 29 3.1.3 Total Sugar and Reducing Sugar 31 3.1.4 Texture 33 3.2 Microbial Factor 35 3.2.1 Total Viable Cells after Inoculation of S. mutans in Test Foods 35 3.3 Radioisotope-labeled PAHA Disc 37 3.3.1 Comparison of 32P Released from the Radioisotope-labeled PAHA after Inoculating S. mutans 37 3.3.2 Confocal Laser Scanning Microscopy 40 3.3.3 Scanning Electronic Microscopy 43 3.4 Modeling of Caries-associated Variables 61 4. Discussion 66 5. Conclusions 81 Bibliography 83 Abstract in Korean 96Docto

A validated single-cell-based strategy to identify diagnostic and therapeutic targets in complex diseases

BACKGROUND: Genomic medicine has paved the way for identifying biomarkers and therapeutically actionable targets for complex diseases, but is complicated by the involvement of thousands of variably expressed genes across multiple cell types. Single-cell RNA-sequencing study (scRNA-seq) allows the characterization of such complex changes in whole organs. METHODS: The study is based on applying network tools to organize and analyze scRNA-seq data from a mouse model of arthritis and human rheumatoid arthritis, in order to find diagnostic biomarkers and therapeutic targets. Diagnostic validation studies were performed using expression profiling data and potential protein biomarkers from prospective clinical studies of 13 diseases. A candidate drug was examined by a treatment study of a mouse model of arthritis, using phenotypic, immunohistochemical, and cellular analyses as read-outs. RESULTS: We performed the first systematic analysis of pathways, potential biomarkers, and drug targets in scRNA-seq data from a complex disease, starting with inflamed joints and lymph nodes from a mouse model of arthritis. We found the involvement of hundreds of pathways, biomarkers, and drug targets that differed greatly between cell types. Analyses of scRNA-seq and GWAS data from human rheumatoid arthritis (RA) supported a similar dispersion of pathogenic mechanisms in different cell types. Thus, systems-level approaches to prioritize biomarkers and drugs are needed. Here, we present a prioritization strategy that is based on constructing network models of disease-associated cell types and interactions using scRNA-seq data from our mouse model of arthritis, as well as human RA, which we term multicellular disease models (MCDMs). We find that the network centrality of MCDM cell types correlates with the enrichment of genes harboring genetic variants associated with RA and thus could potentially be used to prioritize cell types and genes for diagnostics and therapeutics. We validated this hypothesis in a large-scale study of patients with 13 different autoimmune, allergic, infectious, malignant, endocrine, metabolic, and cardiovascular diseases, as well as a therapeutic study of the mouse arthritis model. CONCLUSIONS: Overall, our results support that our strategy has the potential to help prioritize diagnostic and therapeutic targets in human disease.ope

설탕대체제로서 말티톨과 자일리톨의 치아표면 재광화 효과와 쿠키에의 응용

학위논문 (박사)-- 서울대학교 대학원 : 식품영양학과, 2012. 8. 황인경.치아우식증은 치아에서 수산화인회석이 산에 의하여 분해되어 타액 내로 녹아나오는 과정과 타액 내 무기성분이 치면에 침착되는 과정의 균형이 깨어져서 나타나는 질환으로, 재결정화와 광질이탈 현상이 가역 적으로 발생되므로, 이때보다 많은 재광화(再鑛化)를 유도할 수 있는 적절한 조치를 취한다면 치아우식증은 예방될 수 있다. 치아우식증의 측면에서 볼 때 츄잉껌을 저작하는 행위는 치면을 물리적으로 닦아내는 효과가 있어서 치아우식 예방효과를 나타낼 가능성이 기대되나, 껌에 배합되는 당분으로 인하여 오히려 치아우식증 발생을 촉진하는 효과가 우려되기도 하였다. 그러나, 자일리톨 등의 당알콜이 껌속의 설탕성분을 대체함으로써 츄잉껌으로 인한 치아우식 발생우려는 감소되는 추세에 있으며, 일부 연구에서는 당알콜이 배합된 츄잉껌을 저작함으로써 치아 법랑질 표면의 재광화 효과가 나타났다는 보고가 있다. 그러나, 자일 리톨과 같은 당알콜에 비하여 말티톨을 배합한 츄잉껌을 저작하였을 때 치아 법랑질 표면의 재광화 효과에 대해 보고된 바는 거의 없으며, 각 개별성분의 효과에 대해서도 산발적인 결과만이 소수 보고되었을 뿐이다. 이에 본 연구에서는 말티톨, 자일리톨, 설탕, 껌베이스를 배합한 껌의 저작이 치아법랑질의 미세경도변화 및 타액과 치면 세균막 내의 streptococcus mutans수에 미치는 효과를 측정 비교함으로써 치아표면의 재광화 효과를 검토하였다. 4가지 실험껌은 껌베이스, 말티톨, 자일리톨, 설탕에 페퍼민트, 멘톨, 검아라빅, 글리세롤, 소이레시틴, 연화제를 배합한 후 색, 향을 첨가 하여 동일한 크기로 제조하였다. 24명의 실험대상자를 4군 (실험군: 말티톨군, 자일리톨군, 설탕군, 대조군: 껌베이스군)으로 나누어 구강 내 유지장치에 광질이탈시킨 우치시편 3개를 장착한 상태에서 말티톨, 자일리톨, 설탕을 함유한 각각의 껌을 정규식사 사이에 하루에 7회 (9시, 11시, 13시, 15시, 17시, 19시, 21시, 2시간 간격, 1회 저작 분량: 2정, 1회 저작시간: 5분, 총 12정/1일) 1주간 저작하게 하고, 1주간의 휴지기를 두어 구강상태를 안정화시켰다. 껌을 저작한 후 미세경도, streptococcus mutans 의 변화를 측정하고, 주사전자 현미경과 공초점 레이저전자현미경으로 치아표면의 상태를 관찰하였다. 또한,　쿠키에서 설탕의 대체가능성을 알아보기 위하여 자일리톨이나 말티톨을 각각 설탕에 대하여 25%, 50%, 75%, 100% 대체하여 쿠키를 제조한 후 쿠키의 물리적 (퍼짐성, 색도, 조직감, 주사전자형미경), 관능적 특성 (정량적 묘사분석)에 미치는 영향을 살펴보았다． (1)말티톨이나 자일리톨 배합껌을 7일간 저작한 결과, 설탕껌에 비하 여 치아표면의 미세경도(輕度)가 증가되었다 (p<0.001). (2)말티톨이나 자일리톨 배합껌을 저작 후 공초점레이저주사 현미경 으로 치아표면을 관찰한 결과 설탕껌에 비하여 시편의 표면 조도 (照度)가 감소하였다 (p<0.001). (3)실험군과 대조군껌을 저작 후 치아표면을 주사전자현미경 (走使電 子顯微鏡)으로 관찰한 결과 말티톨, 자일리톨, 껌베이스 배합껌의 손상된 법랑소주구조(琺瑯小柱構造)가 설탕껌에 비하여 더 많이 복구되었다 (p<0.001). (4)말티톨, 자일리톨 배합껌은 설탕껌에 비해 streptococcus mutans의 수를 감소시켜 치아법랑질의 재광화 효과가 있었다 (p<0.001). (5)100% 말티톨 대체쿠키의 퍼짐성이 가장 컸고, 50% 말티톨과 25% 자일리톨 대체쿠키의 퍼짐성은 설탕쿠키와 유사했으며, 대체비가 낮아질수록 퍼짐성이 줄어들었다 (p<0.001). (6)비환원성이고 열안정성이 높은 말티톨이나 자일리톨 대체쿠키의 표면색이 설탕 쿠키보다 연했으며, 말티톨과 자일리톨의 대체비가 증가할수록 적색도와 황색도는 감소하고, 명도는 증가하였다 (p<0.001). (7)말티톨이나 자일리톨의 대체비가 증가할수록 텍스쳐는 감소하는 경향을 나타내었고, 75% 자일리톨 대체쿠키는 설탕쿠키의 텍스쳐 와 유사하였다 (p<0.001). (8)75% 말티톨 대체쿠키의 바삭함, 부드러움, 단맛, 향미, 뒷맛은 설탕쿠키와 유사한 경향을 나타내었다 (p<0.001). 말티톨과 자일리톨을 배합한 껌을 저작한 결과 설탕껌(대조군)에 비하여 광질이탈 법랑질(狂疾離脫琺瑯質) 표면구조의 회복정도와 미세 경도를 증가시키고, Streptococcus mutans 의 수를 감소시켜 치아표면의 재광화 효과가 있었으며, 75%말티톨 첨가쿠키는 설탕쿠키와 유사한 물리적, 관능적 특성을 가지고 있어 쿠키의 제조에 적합하였다.The purpose of this study was to investigate the remineralization effects of chewing gum containing maltitol, xylitol and sugar through clinical trials and to determine the applicability of maltitol and xylitol as sugar substitute in cookies through physical measurements and sensory evaluation. Twenty four volunteers were subjected to use an acrylic mandibular removable appliance, which was mounted with enamel specimens in the recesses of the lingual surface, and to chew 2 gum pellets for 5 minutes at a time and 7 times a day (at 9:00, 11:00, 13:00, 15:00, 17:00, 19:00, 21:00, 2 hours intervals). After each test week, there was a 7 day-washout period, in which the subjects could follow their own personal oral hygiene measures with the allocated toothpaste and toothbrush. In order to evaluate the remineralization effect of the gum chewed on the enamel specimens, Vickers' microhardness measurement, SEM (scanning electronic microscopy), and CLSM (confocal laser scanning microscopy) were conducted just after gum chewing. The results were as follows: The Vickers' microhardness of the enamel specimens that chewed the experimental chewing gum containing maltitol or xylitol was significantly higher than that of the sugar gum (p<0.001). The surface roughness of the enamel specimens that chewed the experimental chewing gum containing maltitol or xylitol was significantly lower than that of the control (p<0.001). Unlike those images for the sugar gum, the images for the confocal micro-radiography and SEM of the enamel specimens that chewed gums containing maltitol, xylitol, or gum base only showed the remineralization effect (p<0.001). The SM (Streptococcus mutans) score showed the inhibition effect of the gums containing maltitol or xylitol compared to that of the sugar gum (p<0.05). Application of maltitol or xylitol as a possible substitution for sucrose in cookies was investigated. The characteristics of the cookies prepared with a maltitol or xylitol substitute at 25, 50, 75, and 100% of sucrose were investigated by physical tests (spread ratio, color profile, hardness, and SEM) and sensory evaluation. The results were as follows: the spread ratios of cookies with 50% maltitol and 25% xylitol substitution were similar to that of sucrose cookies (p<0.001). As the substitution level of the maltitol or xylitol increased, the a*(redness) and b*(yellowness) value decreased and the L* (lightness) value of the cookies increased (p<0.001). As the substitution level of the maltitol increased, the hardness of the cookies tended to decrease (p<0.001). The brittleness, softness, sweetness, flavor and aftertaste (sweetness and non-sweetness) of the 75% maltitol-substituted cookies were similar to those of the sucrose cookies by the QDA (quantitative descriptive analysis) profile (p<0.001). These results showed that the gums containing maltitol or xylitol were more effective in the remineralization than that of sucrose. Cookies that maltitol or xylitol substituted for sucrose were of good quality and comparable to the sucrose cookies. Especially, the characteristics of the 75% maltitol-substituted cookies were similar to that of the sucrose cookies and superior to the other cookies that had used various levels of sugar alcohol. Therefore, it is recommended that 75% maltitol cookie could be used as sugar cookie substitute.Abstract i Table of Contents iv List of Tables viii List of Figures ix List of Abbreviations xi Chapter 1. Literature review 1 1.1 Sugar and sugar alcohols 2 1.1.1 Xylitol 5 1.1.1.1 Definition 5 1.1.1.2 Production 6 1.1.1.3 Properties 6 1.1.1.4 Dietary use worldwide 7 1.1.1.5 Safety 7 1.1.1.6 Application for dental care 8 1.1.2 Maltitol 10 1.1.2.1 Definition 10 1.1.2.2 Production 11 1.1.2.3 Metabolism 11 1.1.2.4 Safety 12 1.1.2.5 Multiple ingredient approach for calorie control 13 1.1.2.6 Benefits 14 1.1.2.7 Laxative effects 14 1.1.2.8 Future 15 1.2 Sugar alcohol and health 16 1.3 Sugar alcohol and dental caries 17 Chapter 2. Remieneralization effect of maltitol and xylitol on tooth surface 21 2.1 Introduction 22 2.2 Material & methods 30 2.2.1 Subjects 30 2.2.2 Study design 30 2.2.3 Chewing gum 31 2.2.4 In-situ remineralization measurement 33 2.2.4.1 Preparation of bovine enamel specimens 34 2.2.4.2 Artificial incipient lesion using pH-cycling 34 2.2.4.3 Preparation of removable appliance 35 2.2.4.4 Surface microhardness analysis 37 2.2.4.5 CLSM (confocal laser scanning microscopy) & SEM (scanning electronic microscopy) 39 2.2.5 Microbiological test 40 2.2.5.1 Saliva sampling 40 2.2.5.2 The changes of S. mutans 40 2.2.6 Statistical analysis 42 2.3 Results 43 2.3.1 Surface microhardness 43 2.3.2 Confocal microscopy 45 2.3.3 SEM (scanning electronic microscopy) 49 2.3.4 Microbiological test 52 2.4 Discussion 53 Chapter 3. Application of xylitol and maltitol to cookie as sugar substitute 60 3.1. Introduction 61 3.2. Materials & methods 64 3.2.1 Preparation of cookie 64 3.2.2 Spread ratio 66 3.2.3 Color profile 66 3.2.4 Hardness by probing test 67 3.2.5 SEM (scanning electronic microscopy) 68 3.2.6 Sensory evaluation 68 3.2.7 Statistical analysis 69 3.3. Results 71 3.3.1 Appearance 71 3.3.2 Physical measurement 72 3.3.2.1 Spread ratio 72 3.3.2.2 Color profile 74 3.3.2.3 Hardness by probing test 76 3.3.2.4 SEM 78 3.3.3. Sensory evaluation 81 3.3.3.1 Surface color 81 3.3.3.2 Surface smoothness 81 3.3.3.3 Hardness 82 3.3.3.4 Brittleness 82 3.3.3.5 Softness 83 3.3.3.6 Sweetness 83 3.3.3.7 Flavor 84 3.3.3.8 Aftertaste of sweetness 84 3.3.3.9 Aftertaste of non-sweetness 85 3.3.3.10 Correlation between physical properties 88 3.3.3.11 Correlation between sensory properties 89 3.3.3.12 QDA profiles of cookies 91 3.4 Discussion 93 Chapter 4. Conclusions 98 Chapter 5. References 101 Korean abstract 116Docto

글루코코르티코이드가 편도체 의존적인 공포 기억과 해마 신경 세포 생성에 미치는 영향에 대한 연구

학위논문 (박사)-- 서울대학교 대학원 : 생명과학부, 2013. 2. 김경진.Glucocorticoid (GC) is a steroid hormone playing diverse roles which enable organisms to respond to and to cope with environmental changes such as stress. The secretion of GC is primarily governed by the hypothalamus-pituitary-adrenal (HPA) axis, a major neuroendocrine circuit in the stress response system. Maternal stress-elicited elevation of GC has programming effects on the long-lasting modification of the HPA axis and brain functions in offspring. However, the prolonged impact of maternal stress on emotional learning remains largely unknown. In addition to stress responsiveness and early life programming, another apparent characteristic of GC is its robust circadian rhythm. However, the significance of the functional GC rhythm in the brain function is not well understood yet. Recently, our group generated transgenic mice with adrenal-specific knockdown of canonical clock protein BMAL1 (A-BMKD), which showed attenuated circadian GC rhythm under constant darkness (Son et al., 2008). In Chapter 1, I intended to investigate how maternal stress affects fear memory in the amygdala, a major target of stress in the brain. In Chapter 2, using A-BMKD transgenic mouse line, I investigated the effect of circadian GC oscillation on hippocampal neurogenesis implicating in cognition deficits and mood disorders in Chapter 2. 1. In Chapter 1, I examined whether maternal stress influences on the amygdala-related learning processes. Maternally stressed mice exhibit normal fear memory acquisition as well as synaptic NMDA receptor expression in the amygdalahowever, fear memory consolidation and the activation of related signaling cascades are significantly attenuated. In accordance with these behavioral aspects, maintenance of long-term potentiation (LTP) evoked in the thalamo-lateral amygdala pathway is significantly attenuated in amygdalar slices from maternally stressed animals, though basal synaptic properties and LTP induction were unaffected in these slices. Interestingly, administration of GC immediately after training or LTP induction restores impaired memory consolidation and LTP maintenance, indicating the weakened aversive memory-enhancing effect of GC in maternally stressed mice. Moreover, the membrane-impermeable form of GC mimics the restorative effect in maternally stressed animals, implying the involvement of a nongenomic mechanism. Taken together, it appears that maternal stress causes dysregulation of amygdala-dependent fear memory in adult offspring by an impairment of amygdalar synaptic plasticity in association with reduced nongenomic action of GC on long-term memory formation. 2. In Chapter 2, I focused on hippocampal neurogenesis in A-BMKD transgenic mice under constant darkness for 7 days. The number of newborn neurons in the hippocampus was significantly declined in the transgenic mice. These mice showed depressive mood states, impaired safety memory, and rapidly shutting off stress reactivity, which are known to be regulated by hippocampal neurogenesis. Moreover, enhanced rhythmic translocation of activated glucocorticoid receptor (GR) into hippocampal nucleus by binding to GC was observed against hypo-GC secretion with attenuation rhythm in TG mice. In accordance with this finding, transcript levels of brain-derived neurotrophin factor (BDNF) and its receptor TrkB, which are known to be essential for adult neurogenesis and regulated by GC negatively, were reduced in the hippocampus of A-BMKD transgenic mice. Interestingly, a daily oscillation of plasma GC restored by rhythmic intake of drinking water containing GC recovered not only neurogenesis but also gene expression of BDNF and TrkB in the hippocampus, suggesting that BDNF-related signal cascade is one of candidates responsible for the impaired hippocampal neurogenesis in the transgenic mice. Taken together, GC levels as well as its rhythmic secretion are important for maintaining normal neurogenesis associated with gene expression of BDNF and TrkB in the hippocampus. In conclusion, GC has a critical role in fear memory formation via nongenomic action in the amygdala and the functional circadian rhythm of GC is required for maintaining adult neurogenesis in the hippocampus.ABSTRACT CONTENTS LIST OF FIGURES Background and Purpose Background 2 1. Regulation of glucocorticoid (GC) actions 2 2. Programming effect of GC by maternal stress 14 3. Amygdala-dependent fear memory 18 4. Adult neurogenesis in the hippocampus 23 Purpose 29 Chapter 1. Impairment of fear memory involved with nongenomic glucocorticoid action on the amygdala in maternally stressed adult offspring Abstract 31 Introduction 33 Materials and Methods 35 Results 45 Discussion 84 Chapter 2. Adult neurogenesis in the hippocampus affected by attenuated glucocorticoid rhythmicity Abstract 89 Introduction 91 Materials and Methods 94 Results 102 Discussion 142Docto

Change in Patient’s Ages Who Took an Adenoidectomy for 30 Years

Background and Objectives: Controversy remains regarding whether the age at which patients undergo adenoidectomy is increasing or decreasing. Thus, the aim of this study was to analyze patient age at adenoidectomy over the past 30 years. Subjects and Method: Retrospective analysis of adenoidectomy patients treated between 1984 and 2013 who were confirmed to have adenoid hypertrophy on physical examination and radiologic findings was performed. Patients were divided into three groups by decade, the 1980s, 1990s, and 2000s. The numbers of patients, mean/median age, maximum age, and sex ratio were analyzed for each group. Results: A total of 2,450 patients were enrolled, including 466 cases in the 1980s, 946 in the 1990s, and 1,038 in the 2000s. The mean age of patients was 7.38 years in the 1980s, 8.16 in the 1990s, and 8.37 in the 2000s and has significantly increased since the 1990s (p＜0.05). Conclusion: The mean age of patients who underwent adenoidectomy has increased over the past 30 years. Therefore, adenoid hypertrophy needs to be considered in children of all ages who visit otorhinolaryngologic departments.ope