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      • 생체분해성 망막압정을 이용한 망막고정에 대한 실험적 연구

        김용백,민병무,김창식,박근성,김승영,길숙종,조항진,이성복,노승무,송규상,강대영,조준식,양준묵,정경수,최선웅,이진호,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

        Biodegradable retinal fixation devices obtain mechnical fixation of the retina with desirable chorioretinal scarring and with the potential for local, sustained release of antimetabolites and steroids to inhibit proliferative vitreoretinopathy. We manufactured a biodegradable retinal tack with barb that was designed in order to prevent intrusion from implantation of retinal tacks. This study was carried to evaluate the efficacy for retinal fixation and the capability for sustained release of drugs with a newly designed biodegradable retinal tack Biodegradable retinal tacks were made of polymers of glycolic acids and were designed with barbs in a shape to prevent the disinsertion. Biodegradale retinal tacks are divided into 3 parts, a conical portion that is inserted into the sclera, a cylinder portion that remains in the vitreous, and a neck portion between the pin and the cylinder. The tapered conical end was manufactured to allow easy insertion through the retina and choroid into the sclera. A cylinder portion was manufactured with a tapered angle that fixes firmly into the orifice of 19 gauge spinal needle. A neck portion, 0.4 mm in diameter, was designed to prevent disinsertion from following implantation of retinal tack. The applicator was a 19 gauge spinal needle and its orifice was prepared to 15°angle to accept the tapered cylinder portion of the retinal tack. The retinal tacks, secured in the needles, were passed through the formed vitreous and inserted into the retina, choroid, and sclera and were released by pushing the internal needle, usually within 2-3mm of the medullary ray of the posterior rabbit retina A retinal tack was placed in each of 8 pigmented rabbit eyes. Slit-lamp biomicroscopy, indirect ophthalmoscopy and fundus photography were performed periodically from 1 day to 8 weeks after surgery. Eight eyes were enucleated and studied by light microscopy at 8 weeks. Biomicroscopic evaluation of the animals revealed edemas adjacent to the retinal surfaces immediately after insertion of the biodegradable retinal tacks in all the animals. These edemas disappeared after 1 week. The first noticeable change in the size of retinal tacks was shown after 2weeks. The size of the retinal tacks gradually got smaller, decreasing to about one-half at 4 weeks and about one-third at 8 weeks. All retinal tacks remained in inserted places without any movement for an 8 week period. On light microscopy, epiretinal proliferations were seen to extend into the vitreous cavity. Cellular capsules that lined the inner aspect of the scleral defect caused by tack insertion were found. However the adjacent retina had a normal cytologic appearance and architecture in all specimens. We manufactured a biodegradable retinal tack that is designed to prevent intrusion from implantation of retinal tacks. All biodegradable retinal tacks reduce in size with time, but no retinal tacks extruded from the inserted place. The newly designed biodegradable retinal tack can be used for retinal fixation and may be used as a vehicle for the introduction of pharmacologic agents to prevent the cellular events that promote proliferative vitreoretinopathy.

      • KCI등재후보

        8년간(1992~1999) 산업안전보건연구원에 의뢰된 직업병 심의 사례 분석

        강성규,김규상,김양호,최정근,안연순,진영우,최병순,양정선,김은아,채창호,최용휴,김대성,박정선,정호근 대한산업의학회 2000 대한직업환경의학회지 Vol.12 No.2

        Objectives : Pneumoconisis and noise-induced hearing loss (NIHL) have been reported as main occupational diseases by the Special Health Examination. The Industrial Accident Compensation Insurance has reported various work-related diseases, however, these two diseases occupied almost a half of compensated cases. Therefore, it was not well known about the status of occupational diseases other than pneumoconiosis, NIHL, and cardio-cerebrovascular accident (CVA). This study was conducted to analyze claimed cases as an occupational disease, that was requested to the Korea Industrial Safety and Health Agency (KOSHA). Methods : The local office of the Korea Labor Welfare Corporation (KLWC) has asked the KOSHA for confirmation of claimed cases as an occupational disease. We analyzed 379 cases requested from KLWC, the Ministry of Labor, employers, unions and occupational health agencies from 1992 to 1999. Results : Male was 80.7 % of the requested cases. Their mean age was 42 years old and 75.5 % of them were more than 35 years old. The requested cases were increased rapidly from 25 cases in 1992 to 108 cases in 1999 and the accept rate was 50.7 %. The majority of requested cases were respiratory diseases(22.4%), cancers(18.5%), Neuropsychiatric problems(14.5%), and musculoskeletal problems(13.5%). The accept rate was high in reproductive, respiratory, musculoskeletal and digestive disorders and low in neuropsychiatric, renal and otologic problems and occupational cancers. 73.6% of them were caused by chemical agents, especially 28.5 % were by organic solvents. 67% of them were clinically confirmed at university hospitals. A half of the cases were from KyongIn area, even the request came from the whole country. Conclusions : A claim was common in workers whose age was over 35 years old and exposure history was over 10 years. The respiratory diseases and neuropsychiatric disorders were still main problems in occupational health and occupational cancers was increasing even though its accept rate was not high yet.

      • 생체분해성 고분자를 이용한 사시수술용 제형개발 및 효용성에 대한 연구

        민병무,김용백,김승영,김창식,박근성,길숙종,조항진,이성복,노승무,송규상,강대영,조준식,양준묵,정경수,최선웅,이진호,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

        A new device, muscle clamping system was developed to facilitate exact quatifying technique A strabismus surgery, and reduce the risk of complications. The device is composed of a lower fixing body with three jaws and an upper supporting body. They are used to clip an extraocular muscle and fix it to the sclera with a single bite. Superior rectus recession on 16 rabbit eyes were performed with this new device. Conjunctival injection, muscle adhesion strength, and light microscopic findings were examined at 1, 2, 4 and 8 weeks postoperatively. The Conjunctival injection were minimal, adhesion power ranged from 420 to 600 gram gravity, which is sufficient in withstand the normal pull of human extraocular muscle. In microscopic exam, some Inflammatory cells and fibrosis were found. The new device was technically easy, fast, and accurate, so it may be useful in stabismus surgery.

      • WLL 증폭기 불요방사 성능분석

        김성철,송인근 우송대학교 1999 우송대학교 논문집 Vol.4 No.-

        In this paper the system perfomance degradation resulting from nonlinear transmitter power amplifier which is essential to increase the efficiency is analyzed in a WLL-CDMA system. The power amplifier is modeled by its AM-AM, AM-PM characteristics. Through the investigation of the power spectrum density of the transmitted signal , spectral regrowth or sideband regrowth which is result from amplitude distortion can be seen. All these characteristics result in BER performance degradation due to other user interferences and intersymbol interference. The analysis technique described here applies not only to power amplifier but also to any other nonlinear components such as mixers and switches. Also the effects of adjacent channel interference and supurious emission can be analyzed between different systems.

      • SCOPUSKCI등재

        Streptomyces sp. Y9343이 生産하는 齒面細菌膜 分解酵素의 精製와 特性

        김성주,한홍근,윤정원 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.1

        치면세균막을 제거하거나 형성을 억제하여 치아우식증 예방제를 개발할 목적으로 α-1,3 glucanase를 분비하는 새로운 균주로 부터 분리 정제하여 그 특성을 조사하였다. 불용성 glucan을 유일탄소원으로 하는 agar plate를 제조하여 토양으로 부터 α-1,3 glucanase 분비균주를 탐색한 결과 Streptomyces sp. Y9343을 얻었다. 액체배양시 최적 효소생산조건은 탄소원으로 1% soluble starch와 indcer로 0.5% insoluble glucan을 첨가하였을 때 가장 효율적이었다. α-1,3 glucanase는 황산 암모늄 염석, DEAE-CEllulose 이온교환 크로마토그래피, Sephadex G-75 겔 여과 등에 의하여 32.1배까지 정제되었고 수율은 0.53%이었으며, 이 때의 활성도는 7840.9 U/mg protein이었다. 정제된 α-1,3 glucanase를 SDS-PAGE로 분석한 결과, 단일체임을 확인하였으며, 이 때 분자량은 22,500이었다. 효소의 최적 pH는 6.5이었다. 효소의 최저온도는 37℃이었고, 열에 대한 안정성은 70℃ 이상에서 40%~60%의 효소활성이 상실함을 보였다. Detergent의 영향은 SDS에 의해 83%, Tween 20에 의해서는 약 27% 정도의 활성저해를 받았다. 효소활성의 금속이온에 의한 영향은 Co^2+, Mn^2_+에 의해 각각 81.8, 69.7%의 활성의 증가를 보였고 이들의 최적농도는 10mM이었으며, 반면에 Hg^2+에 의해서는 93.9%의 효소활성의 저해를 나타내었다. 또한 초기속도(30분 이내)에 금속이온에 의한 영향이 큰 것으로 나타났다. α-1,3 glucanase의 불용성 glucan에 대한 K_m 값은 2.50mM이었고, V_max는 0.0431 mM/min이었다. α-1,3 glucanase의 기질특이성을 조사한 결과, 반응 30분 후 IG와 soluble starch에는 각각73, 100%의 높은 분해력을 보였으며, raw starch, dextran T-10에 대해서는 낮은 분해력을 보였다. 한편, 인조치면세균막을 S. mutans로부터 시험관 벽에 제조한 후, α-1,3 glucanase를 처리한 결과 2시간 이내에 완전히 분해 제거되는 것을 알 수 있어 강력한 치아우식예방제로 개발될 수 있음을 보여 주었다. Streptococcus mutans has been implicated as primary causative agents of dental caries by insoluble glucan (IG) in human and experimental animals. An attempt was made to search for the α-1,3 glucanase that degrades IG produced by S. mutans. α-1,3 glucanase was detected in the culture supernatant of microorganisms, which are isolated from soils on agar medium containing IG as a sole carbon source. This Streptomyces sp. hydrolysed IG produced by immobilized S. mutans and was named as Y9343. This enzyme required α-1,3 glucan (IG) as an inducer. The optimum conditions for enzyme production were studied. The enzyme was purified by 30~70% (NH_4)_2SO_4 precipitation, anion exchange chromatography on DEAE-cellulose and gel filration on Sepadex G-75. The purified enzyme has a specific activity of 7840.0 U/mg protein giving 32.1-fold purification and final yield of 0.53%. The molecular weight was estimated to be about 22.5 kDa by SDS-PAGE. The optimum pH and temperature for enzyme reactiorr were 6.5 and 37℃, respectively and the enzyme was relatively stable at the temperature below 60℃. The activity of purified enzyme was enhanced by adding Co^2+, Mn^2+, and Mg^2+ into the medium, whereas inhiited by adding Hg^2+, Zn^2+ and SDS. The K_m and V_max value of α-1,3 glucanase for IG were estimated to be 2.50 mM and 0.0431 mM/min, respectively. The thin layer chromatographic analysis of hydrolysates from IG with α-1,3 glucanase showed that glucose was the main product of reaction. This enzyme activity was about 14 times higher than marketing dextranase as preventive agent against artificial dental caries by S. mutans in TH medium including 5% sucrose after 30 minutes.

      • KCI등재

        Kirschner wire를 사용한 과두하 골절의 구강내 접근법

        김성일,김승룡,백진아,고승오,신효근 대한악안면성형재건외과학회 2001 Maxillofacial Plastic Reconstructive Surgery Vol.23 No.3

        The treatment of mandibular subcondylar fractures is a matter of controversy. The majority of mandibular subcondylar fracture are treated by closed reduction, but the displaced or dislocated mandibular subcondylar fractures may be treated by open reduction. The characteristics of open reduction are the anatomical reduction, the functional restoration, the rapid function, the maintenance of vertical ramus dimension, the better appearance and the less resultant TMJ problem etc. When an open reduction is considered, the wire, miniplate, lag screw and Kirschner wire are available with internal fixation. Of these, Kirschner wire is a simple method relatively and correct positioning of the wire achieves rigid fixation. But many open reduction methods for mandibular subcondylar fractures require extraoral approach. The extraoral approach has some problems, the facial scar and the risk of facial nerve injury. On the other hand, the intraoral approach eliminates the potency of the facial scar and the facial nerve injury, but is difficult to access the operation site. Since the intraoral approach was first described by Silverman (1925), the intraoral approach to the mandibular condyle has been developed with modifications. The purpose of this article is to describe the intraoral technique with the Kirschner wire on mandibular subcondylar fractures. Conclusion : The intraoral reduction with Kirschner wire on mandubular subcondylar fractures avoids the facial scar and facial nerve injury and is simple method to the extraoral approach. And it has minimal morbidity and better esthetics.

      • 부분적 수면박탈이 주간 졸리움, 피로감과 반응시간에 미치는 영향

        김상국,왕성근 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.2

        The purpose of this study was to investigate the effects of early partial sleep deprivation on daytime sleepiness, fatigue and reaction time, measured by the multiple sleep latency test(MSLT), visual analogue scale(VAS) and reaction timer. The subjects were 10 healthy young male college students aged from 19 to 25 years, who had no histories of significant medical or psychiatric illness as well as sleep related problems. Subjects undergown experiment 4 nights and days in the laboratory. The data of the first night and day were baseline. The remaining experiment in the laboratory consisted of 1 hour, 3 hours, 5 hours sleep restriction night and day. Each experiment had intervals more than 3 days to eliminate possible cumulative effects of repetitive partial sleep deprivation. Subjects applied MSLT to investigate their objective daytime sleepiness, VAS to rate subjective feeling of sleepiness and fatigue, and reaction time to investigate visuo-motor performance. MSLT data scored according to the criteria of Rechtschaffen and Kales every 30 seconds, and applied paired-t-test. Sleep restrictions result in the increment of sleepiness index, VAS score, stage 2 sleep. However, sleep latency on MSLT and reaction times were shortened. One hour sleep restriction affects sleep latency on MSLT and visual analogue scale scores mostly. The results suggested that nocturnal sleep restriction may induce daytime sleepiness and fatigue as expected, and shortened reaction time was out of our expectation.

      • KCI등재

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