• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권5호
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• pp.438-443
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• 2004

Objectives : The proper development of the facial structures relies upon a sequence of tightly regulated signaling interactions between the ectoderm and mesoderm involving the participation of several families of signaling molecules. Among these, bone morphogenetic proteins (BMPs) have been suggested to be a key signal that regulates the development of the mandible and the initiation and morphogenesis of the teeth. The aim of this study was to examine the artificial development of the mandibular structures and to examine the role of BMPs on tooth morphogenesis and differentiation using an organ culture system. Materials and Methods : The tooth germs from Ed 11.5, 13.5 mice were dissected, and transplanted into the diastema of the mandible primordia. The mandibles containing the transplanted tooth germs were cultured in vitro. During this period, beads soaked with BMP4 were implanted around the transplanted tooth germs. In addition, a diastema block containing the transplanted tooth germ was dissected, then transferred to an adult mouse kidney. After the organ culture, the developing mandibular explant was removed from the kidney and prepared for the tissue specimens. Odontogeneis of the transplanted tooth germs was examined after Hematoxylin-eosin, Masson-trichrome staining. Results : Proliferation and differentiation of the tooth germs cultured in the diastema was observed. In the BMP4-treated tooth germs, the formation of the first and second molars was noted. The crown of the developing tooth showed the formation of a mature cusp with the deposition of enamel and dentin matrix. In conclusion, it was confirmed that BMP4 is involved in the formation of a dental crown and the differentiation of ameloblasts and odontoblasts of the molar tooth during the development of the transplanted tooth germs.

• Imaging Science in Dentistry
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• 제30권3호
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• pp.169-181
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• 2000

Purpose: To investigate the expression of bone morphogenetic protein (BMP)-2/4 during eary tooth development after irradiation and calcium-deficient diet. Materials and Methods: The pregnant three-week-old Sprague-Dawley rats were used for the study. The control group was non-irradiation/normal diet group (Group 1), and the experimental groups were irradiation/normal diet group (Group 2) and irradiation/calcium-deficient diet group (Group 3). The abdomen of the rats at the 9th day of pregnancy were irradiated with single dose of 350 cGy. The rat pups were sacrificed at embryonic 18 days, 3 days and 14 days after delivery and the maxillae tooth germs were taken. The tissue sections of specimen were stained immunohisto-chemically with anti-BMP-2/4 antibody. Results: At embryo-18 days, immunoreacivity for BMP-2/4 of the Group 1 was modetate in stratum intermedium of dental organ and weak in dental papilla and dental follicle, but that of Group 2 was weak in cell layer of dental organ, and no immunoreacivity was shown in dental papilla and dental follice of Group 2 and in all tissue components of the Group 3. At postnatal-3 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in cell layer of dental organ, odontoblasts and developing alveolar bone, but that of Group of 2 and Group 3 was weak in odontoblasts and developing alveolar bone. At postnatal-14 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in newly formed cementum, alveolar bone and odontoblasts, but that of Group 2 was weaker than that of Group 1. In the Group 3, tooth forming cell layer showed weak immunoreactivity, but other cell layers showed no immunoreactivity. Couclusion : The expression of bone morphogenetic protein (BMP)-2/4 during early tooth development was disturbed after irradiation and calcium-deficient diet.

• 한국양식학회지
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• 제19권3호
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• pp.178-182
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• 2006

이 연구에서는 해산어 초기 자어 사육 과정에서 자어가 섭이하는 로티퍼의 새로운 관찰 및 계수방법을 제시한다. 지금까지는 해산어 자어를 사육하면서 언제부터 로티퍼를 먹이로 이용 가능한지? 그리고 일령이 경과함에 따라 어느 정도 양의 로티퍼를 섭이하는지? 정확하게 분석할 수는 없었다. 왜냐하면 자어가 섭이한 로티퍼(몸통)는 소화기관내에서 소화되어 연구자가 관찰할 수 없었기 때문이다. 그러나 이 연구에서는 이러한 문제점을 해결할 수 있는 새로운 관찰 방법으로서 로티퍼의 저작기(trophi)를 이용하는 방법을 제시한다. 로티퍼는 각 개체마다 한개의 저작기를 가지며 이 저작기는 해산어 자어의 소화기관내에서도 소화되지 않고 그 형태를 유지한다. 따라서 이 연구 결과에 의하면 자어의 소화기관내의 저작기를 관찰하여 계수하는 방법(RTCM; Rotifer Trophi Counting Method)을 이용하여 로티퍼를 최초로 섭이하는 일령은 물론 자어의 일령이 경과함에 따른 포식 로티퍼 개체수를 정확하게 분석할 수 있다.

• 한국작물학회지
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• 제44권2호
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• pp.171-175
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• 1999

Morphological alteration of floral organ development in rice affected by chilling stress was examined. Three varieties of rice were grown under natural conditions and subjected to 12$^{\circ}C$ for 3 or 6 days starting from the ineffective tillering stage, before heading stage and returned to natural condition. Headings were delayed by a 6 day chilling treatment. After heading the panicles were collected and examined for any possible alteration in floral organ development. It appears that there were some differences in sensitivity to chilling stress and degree of injury depending on treatment stages and variety. Chuchungbyeo was the most frequent in producing abnormal flowers among the three varieties examined. Meiosis stage was shown to be the most vulnerable to chilling stress in both Chuchungbyeo and Ilpumbyeo and young panicle differentiation stage was the frequent stage to alter flower development in response to chilling stress only in Chuchungbyeo. It was confirmed that abnormalities occurred in pollen due to chilling stress is a major factor leading to low yield, but to some extent the alterations in carpel development may playa certain role in determining a total yield in response to chilling stress at the reproduction stage in rice. There were abnormalities like extra stigmata, extra lemma, double ovary as well as abnormal anther formation in response to chilling stress. Further studies of the phenocopy observed in rice floral development may be useful for an understanding of the resistance against chilling injury during reproductive stages in rice.

• BMB Reports
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• 제28권5호
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• pp.414-419
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• 1995

The retroviruses carrying ${\nu}-myc$ and ${\nu}-raf$ oncogenes were infected into fetal thymic organ culture (FTOC) to study the molecular mechanisms involved in T cell development. T cell lymphomas in the different stages of T cell development were obtained from this culture system. Interestingly, a few cell lines obtained from this system have a lack of transfected oncogenes, however these cells have the characteristics of transformed cells. In spite of the discrete phenotype of these transformed cell lines, the same pattern of recombination of endogenous c-raf genes was detected from Southern blot analysis. We suggest in this regard that the translocation event of thymocytes, or abnormal promoter activity, can cause lymphomagenesis by way of c-raf.

• 대한수의학회지
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• 제28권1호
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• pp.145-154
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• 1988

제주도 남제주군 성산읍 성산리 성산일출봉 부근에서 생포된 천연기념물(天然記念物) 보호조인 흰꼬리 수리로 부터 Ixodes signatus 약충을 채취하여 생리학적(生理學的) 주요감각기관(主要感覺器官)에 대(對)한 표면미세구조(表面微細構造)를 주사(走査) 전자현미경(電子顯微鏡)으로 관찰(觀察)하였든 바, 영상관찰(映像觀察) 및 사진분석(寫眞分析) 결사(結査) 얻어진 소견(所見)을 요약(要約)하면 다음과 같다. 1. 충체(蟲體) 배면(背面) 및 복면(腹面)에 대(對)한 관찰(觀察)에서 지문상(指紋狀)의 수많은 표면(表面)주름과 다양(多樣)한 크기의 강모(剛毛)들을 볼수 있었으며, 특(特)히 구기부(口器部)에 있어서 크고 잘 발달(發達)된 강모(剛毛) 또는 강모군(剛毛群)을 확인(確認)할 수 있었다. 2. 복면하부(腹面下部)의 항문(肛門)과 항문(肛門)주위에 위로부터 아래로 뻗어내린 항문구(肛門溝)가 뚜렷이 패여져 있었으며 1쌍(雙)으로된 항문엽(肛門葉)에는 각각(各各) 3개씩의 감각성(感覺性) 강모(剛毛)가 위치(位置)하고 있음을 확인(確認)하였다. 3. 측면(側面)에 부착되어 있는 기문판(氣門板) 관찰(觀察)에서 중앙부(中央部)에 단추모양의 구조물(構造物)이 있었으며 변연부(邊緣部)에는 수많은 기공(氣孔)들이 뚫려 있음을 확인(確認)하였다. 4. 사지(四肢)에 대(對)한 관찰결과(觀察結果), 기절(基節)의 외측돌기(外側突起)가 특징적으로 관찰(觀察)되었으며, 각(各) 마디 표면(表面)의 많은 강모(剛毛)와 제1지(第1肢)의 부절에서 화학수용기(化學受容器)의 기능(機能)을 갖고 있는 홀러씨 기관(Haller's organ)을 관찰(觀察)하였다. 5. 타원형(楕圓型)으로 열려있는 홀러씨 기관 주변에서 2종류(種類) 크기의 강모군(剛毛群)을 관찰(觀察)할 수 있었으며, 기관내부(器官內部)에는 갈쿠리 모양의 돌출형(突出型) 감각성(感覺性) 간상체 7개가 정렬되어 있음을 확인(確認)할 수 있었다.

• 한국간담췌외과학회지
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• 제26권4호
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• pp.386-394
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• 2022

Splenic artery steal syndrome (SASS) is a cause of graft hypoperfusion leading to the development of biliary tract complications, graft failure, and in some cases to retransplantation. Its management is still controversial since there is no universal consensus about its prophylaxis and consequently treatment. We present a case of SASS that occurred 48 hours after orthotopic liver transplantation (OLTx) in a 56-year-old male patient with alcoholic cirrhosis and severe portal hypertension, and who was successfully treated by splenic artery embolization. A literature search was performed using the PubMed database, and a total of 22 studies including 4,789 patients who underwent OLTx were relevant to this review. A prophylactic treatment was performed in 260 cases (6.2%) through splenic artery ligation in 98 patients (37.7%) and splenic artery banding in 102 (39.2%). In the patients who did not receive prophylaxis, SASS occurred after OLTx in 266 (5.5%) and was mainly treated by splenic artery embolization (78.9%). Splenic artery ligation and splenectomies were performed, respectively, in 6 and 20 patients (2.3% and 7.5%). The higher rate of complications registered was represented by biliary tract complications (9.7% in patients who received prophylaxis and 11.6% in patients who developed SASS), portal vein thrombosis (respectively, 7.3% and 6.9%), splenectomy (4.8% and 20.9%), and death from sepsis (4.8% and 30.2%). Whenever possible, prevention is the best way to approach SASS, considering all the potential damage arising from an arterial graft hypoperfusion. Where clinical conditions do not permit prophylaxis, an accurate risk assessment and postoperative monitoring are mandatory.

• Molecules and Cells
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• 제19권3호
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• pp.342-349
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• 2005

Cytokinins are adenine derivatives that regulate numerous plant growth and developmental processes, including apical and floral meristem development, stem growth, leaf senescence, apical dominance, and stress tolerance. However, not much is known about how cytokinin biosynthesis and metabolism is regulated. We identified a novel Arabidopsis gene, ALL, encoding an aldolase-like enzyme that regulates cytokinin signaling. An Arabidopsis mutant, all-1D, in which ALL is activated by the nearby insertion of the 35S enhancer, exhibited extreme dwarfism with rolled, dark-green leaves and reduced apical dominance, symptomatic of cytokinin-overproducing mutants. Consistent with this, ARR4 and ARR5, two representative primary cytokinin-responsive genes, were significantly induced in all-1D. Whereas SHOOT MERISTEMLESS (STM) and KNAT1, which regulate meristem development, were also greatly induced, expression of REV and PHV that regulate lateral organ polarity was inhibited. ALL encodes an aldolase-like enzyme that belongs to the HpcH/HpaI aldolase family in prokaryotes and is down-regulated by exogenous cytokinin, possibly through a negative feedback pathway. We propose that ALL is involved in cytokinin biosynthesis or metabolism and acts as a positive regulator of cytokinin signaling during shoot apical meristem development and determination of lateral organ polarity.

• Biomolecules & Therapeutics
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• 제13권2호
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• pp.65-77
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• 2005

Present article reviews about clinical pharmacology of mycophenolic acid (MPA), the active form of mycophenolate mofetil (MMF), as widely used component of immunosuppressive regimens in the organ transplantation field. MMF, used alone or concomitantly with cyclosporine or tacrolimus, has approved in reducing the incidence of acute rejection and has gained widespread use in solid organ such as kidney, heart and liver transplantation. The application of MPA and development of MMF has shown a considerable impact on immunosuppressive therapy for organ transplantation as a new immunosuppressive agent with different mechanism of action from other drugs after early 1990s. In particular aspect, use of MMF, a morpholinoethyl ester of MPA, represented a significant advance in the prevention of organ allograft rejection as well as allograft and patient survival. In considering MMF clinical data, it is important to note that there is a strong correlation between high MPA area under curve(AUC) values and a low probability of acute allograft rejection. Individual trials have shown that MMF is generally well tolerated and revealed that MMF decreased the relative risk of developing chronic allograft rejection compared with azathioprine. Recent clinical investigations suggested that improved effectiveness and tolerability will results from the incorporation of MPA therapeutic drug monitoring into routine clinical practice, providing effective MMF dose individualization in renal and heart transplant patients. Therefore, MMF has a selective immunosuppressive effect with minimal toxicity and has shown to be more effective that other agents as next step of immunosuppressive agents and regimens that deliver effective graft protection and immunosuppression along with a more favorable side effect.

• 한국식품영양학회지
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• 제2권2호
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• pp.40-64
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• 1989

For the study of the effect of dietary phospholipid (PL) on the lipid components of serum and organ tissues in Sprague-Dawley rats, 56 Male-rats were divided into 8 groups, which was composed of 7. One group was fed with basal diet (normal group). And other experimental groups were fed ad libitum with the mixture of carbohydrate. casein salt mixture : vitamin mixture(60:18:4:1) and at the same time fed administratively with 1 gram of phospholipid-free soybean oil, corn oil and sesame oil, and phospholipid-containing soybean oil, corn oil and sesame oil respectively After 60 days the rats were fasted for 12 hours and then decapitated to collect blood and separate organ tissues . The lipid and protein components of serum and organ tissues were analyzed. The results of this study are summarized as follows The supplementation of dietary phospholipid decreases the food efficiency ratio and the growth rate of experimental rats, it increases the level of serum phospholipid and cholesterol ester, but decreases the value of total-cholesterol (T-chol.)/PL ; it decreases the value of albumin/globulin (hyG ratio) of serum protein and it increases the level of phosphatidyl ethanolamine(PE) in serum and organ tissues. And the correlation coefficients among the contents of T-chol., of HDL-chol. and of phospholipid in serum and liver are negative in general. Therefore 1 think that we must eat dietary phospholipid unpurified from vegetable oil to prevent development of atherosclerosis and fat liver.