Endothelial cells are a vital constituent of most mammalian organs and are required to maintain the integrity of these tissues. These cells also play a major role in angiogenesis, inflammatory reactions, and in the regulation of thrombosis. Angiogenesis facilitates pulp formation and produces the vessels which are essential for the maintenance of tooth homeostasis. These vessels can also be used in bone and tissue regeneration, and in surgical procedures to place implants or to remove cancerous tissue. Furthermore, endothelial cell regeneration is the most critical component of the tooth generation process. The aim of the present study was to stimulate endothelial regeneration at a site of acute cyclophosphamide (CP)-induced endothelial injury by treatment with human umbilical cord-derived endothelial/mesenchymal stem cells (hEPCs). We randomly assigned 16 to 20-week-old female NOD/SCID mice into three separate groups, a hEPC (1 × 105 cells) transplanted, 300mg/kg CP treated and saline (control) group. The mice were sacrificed on days 5 and 10 and blood was collected via the abdominal aorta for analysis. The alanine transaminase (ALT), aspartate aminotransferase (AST), serum alkaline phosphatase (s-ALP), and albumin (ALB) levels were then evaluated. Tissue sections from the livers and kidneys were stained with hematoxylin and eosin (HE) for microscopic analysis and were subjected to immunohistochemistry to evaluate any changes in the endothelial layer. CP treatment caused a weight reduction after one day. The kidney/body weight ratio increased in the hEPC treated animals compared with the CP only group at 10 days. Moreover, hEPC treatment resulted in reduced s-ALP, AST, ALT levels compared with the CP only group at 10 days. The CP only animals further showed endothelial injuries at five days which were recovered by hEPC treatment at 10 days. The number of CD31-positive cells was increased by hEPC treatment at both 5 and 10 days. In conclusion, the CP-induced disruption of endothelial cells is recovered by hEPC treatment, indicating that hEPC transplantation has potential benefits in the treatment of endothelial damage.

본 연구에서는 수평변위와 횡력의 저감을 위해서 빌딩외부의 빌딩간 변형차이와 단면2차 모멘트의 최대화를 이용하여 다수의 빌딩으로 구성된 빌딩시스템의 빌딩간 협업제어 방식의 횡력분배 및 변위감소를 제안하였다. 제안된 복합빌딩 시스템의 안전설계를 위한 방안으로 케이블 파단시의 연속붕괴방지를 위한 연결부 정착판의 추가배치와 대공간구조 자체의 질량과 강성 및 공간을 활용한 동조질량감쇠장치의 설계에 대하여 제안하였다. 도심지 인구집중과 지가상승의 필연적 결과에 대한 해결방안으로 제안된 초고밀도 복합빌딩 시스템의 설계 최 적화를 위하여, 3차원 빌딩구조시스템의 2축 대칭조건과 경계조건을 이용하여 2차원 모델을 구성하고 1차부정정구조를 이루는 2차원 모델 의 중요설계변수를 검토하였다. 제안된 복합빌딩구조 시스템은 인구밀도와 지가가 상승하는 도심내 최대밀도구역에서 토지이용의 효율성을 극대화시키고, 새로운 빌딩 또는 기존빌딩구조의 안전성을 증대할 것으로 기대한다.