문제중심학습

나동균 연세대학교 의과대학 의학교육학과 2003 의학교육논단 Vol.5 No.2

웹 사이트 특성이 고객가치, 만족, 충성도에 미치는 영향에 관한 연구

나동균,윤지은 경기대학교 e-비즈니스연구소 2005 e-경영연구 Vol.2 No.1

Unasyn^(�) Tablet(Sultamicillin)의 피부 및 연조직 감염에 대한 임상적 연구

나동균,이영호 최신의학사 1988 最新醫學 Vol.31 No.12

제52차 춘계학술대회 : 심포지엄 1 - Aging and Photoaging ; 주름성형술

나동균 대한피부과학회 2000 초록집 Vol.38 No.10

태아의 창상치유

羅東均 대한의학협회 1995 대한의학협회지 Vol.38 No.11

Protection of Rabbit Kidney from Ischemia/Reperfusion Injury by Green Tea Polyphenol Pretreatment

나동균,한동욱,Hyun Sook Baek,Suong-Hyu Hyon,박병윤,박종철 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.11

Reactive oxygen species (ROS) have been implicated in the pathogenesis of renal injury after ischemia/reperfusion (I/R). Recently, green tea polyphenols (GTP) have been found to protect the myocardium and liver against II/R injury. Less attention, however, has been paid to the protective effects of GTP with respect to the kidneys. This study was designed to determine whether GTP could protect renal cells from ischemic injury. The rabbits were divided into three groups of equal size: control (sham-operated), I/R + vehicle (normal saline) and I/R + GTP groups. Each group consisted of six rabbits. Animals underwent 30, 60, 90 and 120 min of ischemia, followed by 24 h of reperfusion, respectively. GTP (200 microg/kg) or the vehicle was administered 45 min prior to commencement of I/R. The results demonstrated that GTP administration resulted in a significant (P < 0.05) reduction of renal damage after 90 min of ischemia, as indicated by the decreased levels of creatinine and urea nitrogen in serum. These results were confirmed by histological examinations, which showed that GTP pretreatment inhibited necrosis and sloughing of the proximal tubules induced by I/R. Examinations also showed decreased necrotic areas in the medulla and decreased glomerular collapse in the I/R-injured rabbits. Moreover, the infiltration of CD8+ T cells was considerably decreased in GTP-treated kidneys. The results of this study suggest that GTP can reduce renal injury by preventing the oxidative stress dependent on I/R and may be used in renal transplantation as an antioxidant.

방사선 조사가 백서 피부 Fibroblast의 Collagen 합성에 미치는 영향

이영호,유재덕,나동균 大韓成形外科學會 1992 Archives of Plastic Surgery Vol.19 No.4

Keloids are predominantly fibrous sKin tumors that take the form, variable pruritic or tender growth near the site of an injury. Histopathologically, they are rich in various connective tissue components such as collagen. The exact mechanism of keloid formation is at pressure, local injection of syntheic steroids and radiation are now clinically used in the therapy of these lesions. Although radiation is widely used in keloid treatment at present, its mechanism is unknown at the molecular level. In the present study, cultured fibroblasts of rat skin were treated with various radiation doses and the cell grouth and the amounts of collagen and collagen mRNA were measured. Fibroblasts were isolated and cultured from 2-day-old rat skin, and the subcultured cells were irradiated with 300rads at 24hour intervals(one time with 300 rads, 2 times for a total of 600 rads, and 3 times for a total of 900 rads)from 24 hours after the subculture. The thymidine incoration in the culture flasks treated with 300, 600, and 900 rads was 54.6, 29.0, and 23.9% of the control at 2 hours, and 59.8, 40.1, and 34.6% at 8 hours respectively, indicating that radiation severely ingibits the cell growth. The effects of radiation on the amount of collagen were examined by measuring the hydroxyproline, which is a specific amino acid in collagen. The amounts of hydroxyproline in the 300 and 600 rad radiation groups were decreased to 44.2 and 33.3% of that of the control group, and that of the 900 rad radiation group could not be detected. To discriminate whether-these decreases in collagen content by radiation were due only to inhibition of cell growth or whether the radiation had a selective inhibitory effect on collagen content by radiation were due only to inhibition of cell growth or whether the radiation had a selective inhibitory effect on collagen synthesis, we counted the radioactivities of the peptide released by collagenase with the quantitation of DNA. The newly synthesized total protein if the 300, 600 and 900 rad radiation groups was decreased to 66.8, 48.2 and 40.3% of that the control group, respectively, but the total protein per ㎍ DNA was increased to 137.2, 132.3 and 109.7% respectively. The amounts of newly synthesized collagen were also decreased to 66.2, 50.2 and 40.1% of that of the control, but the amount of collagen per ㎍ DNA was increased to 136.1, 138.5 and 40.1% of that of the control, but the amount of collagen per ㎍ DNA was increased to 136.1, 138.5 and 109.3%, respectively, which was a similar pattern to the observed changes of total protein. the radiation did not inhibit the transcription of collagen α1(I)mRAN, according to the result of RAN dot hybridization. These results indicate that radiation has no selective inhibitory effect on collagen synthesis and the decrease of collagen amounts by radiation is due only to its inhibition of cell growth.

Cobalt 60 감마선 조사가 미세혈관 문합에 미치는 영향

박병윤,이영호,나동균 大韓成形外科學會 1988 Archives of Plastic Surgery Vol.15 No.3

The effects previous irradiation to the famoral artery on the patency rate of microvascular anastomosis was evaluated in an experimental study in rats. Pre-operative radiation was given in a groin field using a Cobalt 60 unit, 1.25 Mev, SSD 80cm in a fractionated dose corresponding 3600rad in 3 weeks and 5400 rad in weeks. The femeral artery of each rat was cut and reapproximated using microvascular surgical techniques following 1,2,4,8,12 weeks irradiation. Two weeks after surgery, the same femoral artery was evaluated for patency and pathologic changes. There was no notable effects of irradiation on the patency of subsequently performed anastomosis of these femoral arteries which was 8-10 mm in dameter. Radiation effects were obvious on histological examination, but the anatomical and physiological alterations apparently were not severe enough to cause early thrombosis after microsurgical mainpulation of these vessels.

고압산소요법과 Prostaglandin 합성억압제 투여가 백서 임의형 피부편 생존에 미치는 영향

이명선,나동균 大韓成形外科學會 1988 Archives of Plastic Surgery Vol.15 No.3

The effects of hyperbaric oxygen, prostaglandin synthesis inhibitor and combination of the two on the survival rate of random pattem flaps were evaluated in an experimental study in rats. Sixty rats were divided into six groups. Cephalic based random pattem flaps were designed on the back of the rats and control group were not given any treatment. Group I rats were treated with hyperbaric oxygen postoperatively. Group II rats were treated with hyperbaric oxygen postoperatively. Group II rats were treated with flubiprofen (prostagladin synthesis inhibitor) before flap surgery and hyperbaric oxygen therapy was followed. Group III rats were given flubiprofen and hyperbaric oxygen postoperatively. Group IV rats were given flubiprofen alone before surgery. Group V rats were given flubiprofen after sugery. The survival rate to the total flap was calculated and following results were obtained. The mean survival rate of the flaps was 39.4 ±14.9% in control, 50.6 ±7.3 % in group I, 48.7 ±12.4 % in group II, 46.4 ±9.9% in group III, 55.8 ± 10.2% group IV and 37.0 ±9.3% in group V. The survival rate of the flaps were increased in group, I, II, III, IV than control but group V revealed no significant changes. In conclusion, flubiprofen should be treated before flap surgery to increase the survival rate. The combination of hyperbaric oxygen and flubiprofen did not show synergistic effect on the survival rate of the flap.

시력 장애를 동반한 안면골 골절

탁관철,오성원,이영호,나동균 大韓成形外科學會 1987 Archives of Plastic Surgery Vol.14 No.4

A sudden monocular blindness following the blunt trauma around the orbit is not new. However, the nature of the lesion did not surface until 1845, when Nuhn suggested that the optic nerve might be the site of the lesion. The optic nerve injury is caused by stretching, tearing, torsion, contusion of the optic nerve or ophthalmic artery, or by skeletal distortion with hematoma which compressed the nutrient vessel and verve. Decompression of the optic nerve was thought to be the most effective treatment. Clinical and experimental studies show the advantage of steroids in reducing traumatically induced CNS damage, so the use of megadose steroids should be beneficial in reducing microcirculatory spasm, edema and nerve cell necrosis. Anatomically distrubed optic canal was decompressed with surgical intervention for improvement of visual acuity. Blindness following the blunt trauma will be prevented by immediate and active management as surgical intervention and/or megadose steroids.