• 생명과학회지
• /
• 제25권6호
• /
• pp.724-731
• /
• 2015

중간엽줄기세포는 성체줄기세포의 한 종류로, 자기재생산능력(self-renwal)과 다분화능(multipotency)을 가지고 있고, 다양한 자양인자(trophic factors)들을 분비한다. 뿐만 아니라, 중간엽줄기세포는 골수, 지방, 탯줄과 같은 조직에서 쉽게 얻을 수 있기 때문에 줄기세포치료에 좋은 도구로 이용되고 있다. 하지만, 줄기세포치료의 효율성을 높이기 위해 추출한 세포의 개체 수를 늘리는 과정에서 중간엽줄기세포는 점차적인 노화를 겪게 되고, 이는 줄기세포 자체의 기능적인 감소를 야기한다. 인체 내에서, 노화된 줄기세포는 조직 내의 항상성 유지에 부정적인 영향 을 미치게 되고, 이러한 상태가 지속되면 대표적인 노인성 질환인 퇴행성 질환의 원인이 된다. 최근 연구들에 의하면 중간엽줄기세포가 노화를 겪을 때, 노화 관련된 DNA 메틸화 패턴의 변화와 히스톤의 변형이 일어남을 확인하였다. 또한, 중간엽줄기세포의 노화에 있어서 DNA 메틸화효소(DNA methyltransferase) 억제제와 히스톤 아세틸화효소(histone deacetylase) 억제제가 부분적으로 노화를 개선하는 효과를 관찰한 연구사례들이 있다. 본 총설에서는, 노화에 따른 후생유전학적인 변화에 의해, 조절되는 노화 관련 유전자들과 중간엽줄기세포의 노화에 대한 연구사례들을 분석하여 서술하고자 한다.

• 한국지반환경공학회 논문집
• /
• 제11권11호
• /
• pp.63-75
• /
• 2010

중금속으로 오염된 부지는 다양한 공법으로 복원이 가능하나 오염부지가 비교적 넓은 경우 중금속을 부지로부터 제거하는 적극적 공법은 기술적 어려움과 비용의 문제로 쉽게 사용할 수 없다. 그러므로 토양에서 중금속의 용출을 차단 및 지연하는 안정화 공법이 보다 현실적이라 할 수 있다. 본 연구에서는 국내의 비교적 큰 규모의 중금속 오염토양인 제련소 오염토양을 대상으로 magnetite, hematite, zeolite-A, zeolite-X, zeolite-Y, zinc oxide, calcium oxide, carbon trioxide, manganese oxide, manganese dioxide, fish bone, sodium phosphate 등의 다양한 안정화제의 적용성실험을 수행하였다. 비소, 납, 구리, 니켈, 아연 등의 다중 중금속으로 오염된 토양의 경우 1종의 안정화제로 안정화가 어려우며 기존 연구에서 보고된 특정 중금속의 안정화에 우수한 성능을 갖는 안정화제의 경우에도 다른 중금속의 안정화에 기여하지 못하거나 용출을 촉진하는 경향을 보였다. 시간이 경과함에 따라 안정화 효율이 증가하였다. 니켈과 납의 경우 calcium oxide, carbon trioxide, manganese oxide 등의 안정화제가 효과가 있으며 특히 연속추출에서 물에 의한 추출부분에서 안정화 효율이 높았다. 구리의 경우 manganese oxide, zeolite 등이 효과가 크며 연속추출에서 exchangeable 추출부분에서 안정화 효율이 높았다. 비소의 경우 magnetite에 의한 안정화 효과를 보이며 대부분의 metal oxide와 phosphate 에 의해 용출이 촉진되는 부작용을 보였다. 그러므로 다양한 중금속으로 오염된 토양의 경우 2종 이상의 안정화제를 사용하여야 하며 역효과를 일으키는 안정화제의 사용을 배제하고 중금속의 농도에 따라 사용량 및 안정화 기간을 달리하여야 할 것으로 판단된다.

• Archives of Plastic Surgery
• /
• 제36권5호
• /
• pp.605-610
• /
• 2009

Purpose: Substantial tissue necrosis after snake bites requiring coverage with flap surgery is extremely rare. In this article, we report 7 cases of soft tissue defects in the upper and the lower extremities caused by snake bites, which needed to be covered with flaps. Among the vast mass of publications on snake bites there has been no report that focuses on flap coverage of soft tissue defects due to snake bite sequelae. Methods: Seven cases of soft tissue defects with tendon, ligament, or bone exposure after snake bites were included. All patients were males without comorbidities, the average age was 35 years. All of them required coverage with a flap. In 6 cases, the defect was localized on the upper extremity, in one case the lesion was on the lower extremity. Local flaps were used in 6 cases, one case was covered with a free flap. The surgical procedures included one kite flap, one cross finger flap and digital nerve reconstruction with a sural nerve graft, one reverse proximal phalanx island flap, one groin flap, one adipofascial flap, one neurovascular island flap, and one anterolateral thigh free flap. The average interval from injury to flap surgery was 23.7 days. Results: All flaps survived without complication. All patients regained a good range of motion in the affected extremity. Donor site morbidities were not observed. The case with digital nerve reconstruction recovered a static two point discrimination of 7 mm. The patient with foot reconstruction can wear normal shoes without a debulking procedure. Conclusion: The majority of soft tissue affection after snake bites can be treated conservatively. Some severe cases, however, may require the coverage with flap surgery after radical debridement, especially, if there is exposure of tendon, bone or neurovascular structures. There is no doubt that definite coverage should be performed as soon as possible. But we also want to point out that this principle must not lead to a premature coverage. If the surgeon is not certain that the wound is free of necrotic tissue or remnants of venom, it is better to take enough time to get a proper wound before flap surgery in order to obtain a good functional and cosmetic result.

• Journal of Korean Neurosurgical Society
• /
• 제62권4호
• /
• pp.450-457
• /
• 2019

Objective : Anterior cervical discectomy and fusion (ACDF) is commonly used surgical procedure for cervical degenerative disease. Among the various intervertebral spacers, the use of allografts is increasing due to its advantages such as no harvest site complications and low rate of subsidence. Although subsidence is a rare complication, graft collapse is often observed in the follow-up period. Graft collapse is defined as a significant graft height loss without subsidence, which can lead to clinical deterioration due to foraminal re-stenosis or segmental kyphosis. However, studies about the collapse of allografts are very limited. In this study, we evaluated risk factors associated with graft collapse. Methods : We retrospectively reviewed 33 patients who underwent two level ACDF with anterior plating using allogenous bone graft from January 2013 to June 2017. Various factors related to cervical sagittal alignment were measured preoperatively (PRE), postoperatively (POST), and last follow-up. The collapse was defined as the ratio of decrement from POST disc height to follow-up disc height. We also defined significant collapses as disc heights that were decreased by 30% or more after surgery. The intraoperative distraction was defined as the ratio of increment from PRE disc height to POST disc height. Results : The subsidence rate was 4.5% and graft collapse rate was 28.8%. The pseudarthrosis rate was 16.7% and there was no association between pseudarthrosis and graft collapse. Among the collapse-related risk factors, pre-operative segmental angle (p=0.047) and intra-operative distraction (p=0.003) were significantly related to allograft collapse. The cut-off value of intraoperative distraction ${\geq}37.3%$ was significantly associated with collapse (p=0.009; odds ratio, 4.622; 95% confidence interval, 1.470-14.531). The average time of events were as follows: collapse, $5.8{\pm}5.7months$; subsidence, $0.99{\pm}0.50months$; and instrument failure, $9.13{\pm}0.50months$. Conclusion : We experienced a higher frequency rate of collapse than subsidence in ACDF using an allograft. Of the various preoperative factors, intra-operative distraction was the most predictable factor of the allograft collapse. This was especially true when the intraoperative distraction was more than 37%, in which case the occurrence of graft collapse increased 4.6 times. We also found that instrument failure occurs only after the allograft collapse.

• 구강회복응용과학지
• /
• 제36권4호
• /
• pp.262-271
• /
• 2020

변연골 하방으로까지 파절선이 연장된 치아를 수복하기 위해 파절선의 노출 및 생물학적 폭경의 재확립을 위한 삭제형 골수술을 동반한 외과적 치관 연장술을 고려해 볼 수 있다. 그러나 이 술식은 특히 전치부에서 심미성을 훼손시킬 수 있다. 따라서 지지골과 치은을 희생시키지 않으면서 파절선을 치조와 하방에서 상방으로 위치 시킬 수 있는 교정적 정출술이 권장된다. 이 술식은 생물학적 폭경의 재확립과 더불어 수복물을 건전한 치아 구조에 위치할 수 있도록 해 준다. 또 다른 대안으로, 교정적 정출술 보다 방법이 간단하며 시간이 적게 소요되고 한번의 술식만으로 정출이 완료되는 외과적 정출술도 고려해 볼 수 있다. 외과적 정출술을 이용할 경우 구강내 교정 장치를 위치시키고 조정하기 위해 환자가 치과에 여러번 방문할 필요가 없다. 본 연구에서는 상악 중절치에서 치관-치근 파절이 발생한 경우 교정적 정출술 또는 외과적 정출술을 통한 다각적 방법을 병용함으로써 성공적으로 수복한 증례를 보고하고자 한다.

• Journal of Korean Neurosurgical Society
• /
• 제61권4호
• /
• pp.503-508
• /
• 2018

Objective : Anterior odontoid screw fixation is a safe and effective method for the treatment of odontoid fractures. The surgical technique is recommended for perforation of the apical cortex of the dens by the lag screw. However, overpenetration of the apical cortex may lead to potentially serious complications such as damages of adjacent vascular and neural structures. The purpose of this study was to assess the role of three-dimensional computed tomography (CT) scan to evaluate the safe margin beyond dens tip to ventral dura for anterior odontoid screw fixation. Methods : We retrospectively analyzed the three-dimensional CT scans of the cervical spines in 55 consecutive patients at our trauma center. The patients included 38 males and 17 females aged between 22 and 73 years (mean age${\pm}$standard deviation, $45.8{\pm}14.2years$). Using sagittal images of 3-dimensional CT scan, the safe margins beyond dens tip to ventral dura as well as the appropriate screw length were measured. Results : The mean width of the apical dens tip was $9.6{\pm}1.1mm$. The mean lengths from the screw entry point to the apical dens tip and posterior end of dens tip were $39.2{\pm}2.6mm$ and $36.6{\pm}2.4mm$. The safe margin beyond apical dens tip to ventral dura was $7.7{\pm}1.7mm$. However, the safe margin beyond the posterior end of dens tip to ventral dura was decreased to $2.1{\pm}3.2mm$, which was statistically significant (p<0.01). There were no significant differences of safe margins beyond dens tip to ventral dura with patient gender and age. Conclusion : Extension by several millimeters beyond the dens tip is safe, if the trajectory of anterior odontoid screw is targeted at the apical dens tip. However, if the trajectory of the screw is targeted to the posterior end of dens tip, extension beyond dens tip may lead to damage immediately adjacent to the vental dura mater.

• IMMUNE NETWORK
• /
• 제15권2호
• /
• pp.73-82
• /
• 2015

Respiratory syncytial virus (RSV) infection is recognized by the innate immune system through Toll like receptors (TLRs) and retinoic acid inducible gene I. These pathways lead to the activation of type I interferons and resistance to infection. In contrast to TLRs, very few studies have examined the role of NOD-like receptors in viral recognition and induction of adaptive immune responses to RSV. Caspase-1 plays an essential role in the immune response via the maturation of the proinflammatory cytokines IL-$1{\beta}$ and IL-18. However, the role of caspase-1 in RSV infection in vivo is unknown. We demonstrate that RSV infection induces IL-$1{\beta}$ secretion and that caspase-1 deficiency in bone marrow derived dendritic cells leads to defective IL-$1{\beta}$ production, while normal RSV viral clearance and T cell responses are observed in caspase-1 deficient mice following respiratory infection with RSV. The frequencies of IFN-${\gamma}$ producing or RSV specific T cells in lungs from caspase-1 deficient mice are not impaired. In addition, we demonstrate that caspase-1 deficient neonatal or young mice also exhibit normal immune responses. Furthermore, we find that IL-1R deficient mice infected with RSV exhibit normal Th1 and cytotoxic T lymphocytes (CTL) immune responses. Collectively, these results demonstrate that in contrast to TLR pathways, caspase-1 might not play a central role in the induction of Th1 and CTL immune responses to RSV.

• 대한영양사협회학술지
• /
• 제22권2호
• /
• pp.106-117
• /
• 2016

Osteoporosis is a major health problem that can lead to mortality. This study was conducted to estimate the prevalence of osteopenia and osteoporosis separately and to assess the risk factors associated with osteopenia/osteoporosis in Korean men aged 50 years and over. A total of 1,136 subjects were analyzed among the participants of the Korea National Health and Nutrition Examination Survey (KNHANES) 2010~2011 by using SPSS statistics complex samples (windows ver. 23.0). The prevalence rates of osteopenia and osteoporosis were 46.3% and 7.3%, respectively, and the mean ages of both osteopenia and osteoporosis risk groups were significantly higher than that of the normal group. The mean values for lifetime tallest height and bone mineral density in whole body, total femur, femoral neck, and lumbar spine were significantly lower in the risk group(osteopenia/osteoporosis) than in the normal group, whereas the mean values for height, body weight, BMI, waist circumference, alkaline phosphatase, parathyroid hormone, fasting blood glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglycerides of the two groups showed no significant differences. The intakes of energy and carbohydrates were significantly higher in the risk group than in the normal group. The results of multiple logistic regression showed that being underweight and having hypercholesterolemia were significantly related with the prevalence of osteopenia/osteoporosis, whereas health habits such as smoking and exercise, chronic diseases such as obesity and hypertension, and nutrient intakes were not. These findings suggest the need for further studies to examine osteopenia/osteoporosis risk factors and outcomes specificly focused on Korean men.

• 한국임상수의학회지
• /
• 제37권3호
• /
• pp.163-167
• /
• 2020

A 13-month-old, 3.3 kg castrated male Shih-tzu presented with right hindlimb lameness. The physical examination revealed atrophy of the right thigh muscles, hyperextension of the stifle joint and external torsion of the tibia. On the radiographic examination, patella alta and genu recurvatum were observed. A biapical deformity of the tibia and external torsion of the distal tibia were detected by computed tomography (CT). A three-dimensional (3D) printed bone model was designed and constructed for the preoperative plan prior to surgery. Rectus femoris muscle transposition, femoral shortening ostectomy and open wedge osteotomy of the distal tibia were performed using hybrid external skele/t0al fixation (hybrid-ESF). A dynamic stifle flexion apparatus was used to prevent recurrence of a quadriceps contracture (QC). Intense physiotherapy was administered postoperatively. The dog began to use the affected limb one week after surgery. Functional improvement in the affected limb was observed, and full weight-bearing was possible at 3 months after surgery. Union of the osteotomy lines was observed at 3 months, and the stifle joint was fully movable at 7 months after surgery. Regarding the treatments for QC, these methods may be excellent candidates, as they do not lead to severe damage to the limb or amputation.

• 대한소아치과학회지
• /
• 제26권2호
• /
• pp.232-239
• /
• 1999

유치의 탈락과 영구치의 맹출은 정상적이고 예측 가능한 생리적인 과정이다. 치아 발육의 정확한 예측은 어린이의 치료 계획의 수립에 있어서 중요하다. 어린이의 연령과 그에 해당하는 치아 발육의 정상치가 여러 연구자들에 의해 조사되었다. 그러나 다양한 요소에 의해 치아의 정상 발육이 영향받을 수 있고 치아의 맹출을 촉진하거나 지연시킬 수 있다. 특히 농양이 있던 유치의 조기 발거나 탈락은 영구 계승치의 맹출에 뚜렷한 영향을 미칠 수 있다. 유치의 농양은 영구치를 덮은 골을 흡수시키고 따라서 발육상태에 관계 없이 영구치는 맹출할 수 있다. 유구치가 일찍 탈락 또는 발거되고 영구 계승치의 맹출이 조기에 일어나면 치아의 편향과 회전, 맹출 순서의 변경, 이웃 치아의 매복, 중심선 변위 등의 다양한 중요한 사건이 발생할 수 있다. 이에 저자는 서울대학교 병원 소아치과에 내원한 환아들의 조기 맹출한 영구 계승치의 임상적, 방사선학적 특징과 그로 인한 영향을 알아보고, 그에 따른 적합한 처치와 추후 관찰 사항을 보고하고자 한다.