農民技術受容에 影響을 주는 要因의 比較分析 : 關係機關과 情報傳達媒體를 中心으로

鄭址雄,崔敏浩,金性洙,徐圭善,李昶植 서울大學校 農科大學 1984 서울대농학연구지 Vol.9 No.2

The purpose of the study was to analyze the variables affecting farmers' adoption process of agricultural innovations in Korea. Specific objectives of the study were to ; (1) review the adoption process and the variables associated with this process, (2) investigate the rate of adoption of selected agricultural innovations in the fields of rice production, animal husbandary and horticulture, (3) analyze communication media and change agencies or institutions which affected the adoption of agricultural innovations, and (4) identify the relations of the farmers' adoption and communication exposure behavior. Data for the study were collected from 393 cluster sampled farmers out of selected 17 rural villages in Korea. Five graduate students and three faculty members of Seoul National University participated in conducting interview with pre-tested questionnairs. The data were analyzed by HP 3,000 computer in the College of Agriculture, Seoul National University. Major statistical techniques used for the study were frequency distribution, chi-square and discriminant analysis. Statistical significance was tested at .05 level. The major findings of the study were as follows : 1. Variables associated with the agricultural adoption process were classified into the following six categories ; (1) perceived characteristics of agricultural innovations, (2) personality and characteristics of adopters, (3) the patterns of communication media or channels, (4) efforts of change agents. (5) priorities in agricultural development policies, and (6) characteristics of social system. 2. Rats of adoption were about 83% in application of silicate fertilizers on rice seed bed, 41% in feeding calf starter known as artificial milk to calves, 56% vinyl mulching practices in vegetable cultivation, and 67% in spreading raw rice straw on paddy land to improve soil conditions. 3. Time lag between awareness and adoption appeared to be about seven months in application of silicate fertilizers on rice seed bed, and about a year in feeding calf starter. 4. Change agent interpersonal communication revealed to be the most important factor affecting farmers' awareness in application of silicate fertilizers on rice seed bed, in feeding calf starter, and in spreading raw rice straw on paddy land, while localite interpersonal communication in vinyl mulching practices in vegetable cultivation. 5. Change agent interpersonal communication appeared to be the most important factor affecting farmers' adoption in application of silicate fertilizers on rice seed bed and in feeding calf-starter, Localite interpersonal communications were more important in vinyl mulching practices of vegetable cultivation and in spreading raw rice straw. Localite interpersonal communications were more important factor at adoption stage than at awarenss stage. 6. Agricultural extension agencies appeared to be the most important factor affecting farmers' adoption in application of silicate fertilizers on rice seed bed, in feeding calf starter, and in vinyl mulching practices. Based on the results of this study, the following are recommended for further development of agricultural extension services and effective adoption process of agricultural innovation. 1. The variables associated with the agricultural innovation decision process should be taken into consideration to improve effectiveness of change agencies or agricultural extension services. 2. Effective use of communication media along with the feedback messages from the change agency as well as client system be considered to increase effectiveness and meaningfulness of both systems. 3. Innovative agricultural research be continually sharpen its focus on the highest priority needs of client system by utilizing feedback from farmers through the communication link of change agents. 4. A long-term educational approach by using various communication media be emphasized, and regular field survey on innovation-decision process will prevent discontinuance of innovations.

Graves 병 환자에서 항갑상선제 투여에 의한 TSH 수용체 항체의 변동에 관한 연구 : 치료 용량 및 기간에 따른 차이 및 임상상과의 관계 its relation to dose and duration of treatment~and clinical features

이문호,조보연,문대혁,고창순,민헌기,서교일 대한내과학회 1986 대한내과학회지 Vol.30 No.3

We undertook a prospective study of 59 patients with Graves' disease in order to clarify the influence of antithyroid drug on the immunological indices and to determine the association of the changes of TSH receptor antibodies activities with drug dosage, duration of treatment and clinical features according to mode of antitbyroid drugs treatment. Patients were divided into two groups. High dose group included 28 patients and conventional dose group 31 patients. We measured TBII activities, antimicrosomal antibodies, and the size of goiter every 3 months, comparing them with clinical features and laboratory findings. TBII activities declined from R months until 9 months following drug treatment. Therafter no significant change of TBII activities were observed. Antimicrosomal antibodies showed the same pattern of change. There was no statistically significant difference of declining rate of TBII activities, antimicrosomal antibodies, and reduction of size of thyroid between two treatment groups. TBII activities fell into normal range in 15 patients among those 44 patients who had been followed for more than 9 months (8 high dose group, 7 conventional dose group). In those 15 patients, TBII activities and frequency of exophthalmos were less than those whose TBII activity did not normalized. We conclude that TSH receptor antibodies activities and antithyroid autoantibodies are diminished by antithyroid drug treatment in patients with Graves disease and there is no relationship between dose of drug and declining of TBII activities. We suggest that changing levels of TBII activities might be secondary phenomenon which can be achieved by control of thyroid function by antithyroid drug rather than direct immunosuppressive effect of antithyroid drug per se.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

난치성 만성정신분열증 환자의 생활의 질에 미치는 정신사회치료 프로그램의 효과에 대한 예비연구

송동호,배민진,이종호,이홍식,김선경,서호석,김찬형,전지용 大韓神經精神醫學會 1995 신경정신의학 Vol.34 No.4

Objects : Recent studies of psychosocial adjustment after hospitalization have found that the combination of maintenance antipsychotic drug treatment and psychosocial treatment including psychoeducational program are highly predictive of social rehabilitation and reduction of subsequent relapse. Two groups of patients with refractory chronic schizophrenia were preliminarily compared to determine the effect of a psychosocial treatment program on the quality of life in refractory chronic schizophrenics in an open comparative trial. Methods : One group(N=11) was assigned to approximately six months of the psychosocial treatment program(including psychoeducation program and activity program such as interpersonal relationship program, social skill training, self management program, outings, etc), in a group format, twice a week and a fixed maintenance dosage of clozapine ; while scale(QLS) was used to provide an objective measure of changes in patient's psychosocial functioning and a general assessment of psychopathology was made using the Brief Psychiatric Rating Scale(BPRS). Results : Both BPRS total positive score and the QLS total score, especially in the intrapsychic foundation factor of the scale showed a statistically significant improvement in the psychosocial treatment group. But there was no significant change in both BPRS and QLS scores over a 6-month period in the non-psychosocial treatment group. A significant negative correlation was found between the negative symptom and changes of QLS total, instrumental role and common object and activities scores respectively after receiving a 6-month of the psychosocial treatment program. Conclusion : These results suggest that a psychosocial treatment program including the integration of psychoeducation and a skill training oriented activity program serve as an outpatient treatment modality to improve the quality of the life in refractory chronic schizophrenia. To further clarify the effect of psychosocial treatment in chronic schizophrenia, a randomized trial should be done.

고혈당증과 신적출 후 신증의 실험적 흰쥐 모형에서 신사구체의 형태계측학적 연구 - 사구체 경화증의 발달 과정과 기전에 관한 연구 -

심영웅 ( Young Woong Shim ),설미영 ( Mee Young Sol ),이경민 ( Kyeong Min Lee ),최경운 ( Kyung Un Choi ),김지연 ( Jee Yeon Kim ),이진숙 ( Jin Sook Lee ),박도윤 ( Do Youn Park ),이창훈 ( Chang Hoon Lee ),서강석 ( Kang Suek Suh ) 대한신장학회 2002 Kidney Research and Clinical Practice Vol.21 No.6

목적 : 당뇨병의 가장 흔한 합병증의 당뇨병성 신중에서 현저한 조직 변화인 사구체의 섬유화와 이와 유사한 조직 소견을 보이는 다른 질병들과의 관련성 및 섬유화 기전의 기전의 일단을 밝히기 위하여 연구를 시행하였다. 방 법 : 당뇨병성 신증과 신 조직 일부 소실 후 발생하는 신 적출 후 신증, 생리적 노령화로 인한 사구체 섬유화 등에서 섬유화가 일어나는 시기와 부위, 섬유화의 정도와 시간 경과에 따른 변화 등을 조사하기 위하여 실험 동물 모형을 이용하여 형태계측학적 연구를 하였다. 수컷 Sprague-Dowley (이하 S-D) 흰쥐에 streptozotocin을 꼬리 정맥으로 투여하여 당뇨병성 신증 모델을 만들고, S-D 백서의 우측 신장을 절제하여 과여과 모형을 만들었다. 시술 후 일정 기간이 지난 후 시기별로 희생시켜 Sirius red 염색 표본을 만들어 시구체 단면적과 실질의 섬유화 정도를 측정하고, 전자현미경으로 얻은 사구체 소견에서 메산지움 기질의 면적, 사구체 기저막의 두께, 근위우곡세뇨관 기저막의 두께 등을 조사하였다. 이들에서 질병 시기에 따른 변화, 두 실험군 사이의 차이, 정상 대조군 및 생리적 노화 대조군과의 차이 등을 분석하였다. 결 과 : 당뇨병성 신증 모델에서 사구체 단면적은 실험8주 이후 24주까지 전 예에서 정상 대조군에 비해 크기가 의의있게 증가하였고 신 실질과 사구체 내의 섬유화는 실험 2주 째부터 대조군에 비해 의의있는 교원질 양의 증가가 있었다. 사구체 기저막은 streptozotocin 투여 1주에 희생시킨 군에서도 의의있는 두께의 증가가 있었고, 세뇨관 기저막도 3주에 측정한 군에서부터 현저한 두께의 증가가 있었다. 우측신 절제를 시행한 모형에서 사구체 평면적은 실험 7주군에서 커진 소견이 나타났고 16주 이후의 군대에서는 현저한 크기의 증가 소견이 있었다. 신실질과 사구체의 교원질 염색 소견에서 2주 이후 전 기간에 걸쳐 교원질 양의 증가가 있었고, 사구체 기저막과 세뇨관 기저막 두께는 술 후 2주에 희생시킨 군부터 두께가 의의있게 증가하였다. 생리적 노화과정을 거친 군에서도 사구체의 섬유화가 나타났는데 당뇨병 모형과 신적출 모형에 비해 그 정도는 덜하였다. 당뇨병 모형과 신적출 모형 사이의 사구체 조직 변화는 실험 기간이 긴 군들에서 사구체 평면적의 크기, 교원질 양의 증가, GBM과 TBM의 두께 등이 두 군 모두 현저한 증가를 보였고 신적출 모형에서 실험 최종 기간이 같지 않아 실험 수치의 비교가 의미가 없을 것으로 생각된다. 결 론 : 이상의 성적에 의거하면 신사구체와 간질의 섬유화, GBM과 TBM의 두께 증가는 당뇨병성 신증만의 특징적인 조직 변화는 아니고 신 실질 일부 소실이 일어나는 사구체 질환에서 공통적으로 일어나는 소견이다. 그러므로 본 연구의 대상이 된 당뇨병성 신중, 신적출 후 신증, 그리고 생리적 노화 과정 등에서 공통적으로 나타나는 사구체 모세관의 혈역동학적 변화가 사구체의 섬유화에 병인기전을 밝히는데 중요한 요소가 될 것으로 사료된다. Objective :Diabetic nephropathy and ablation nephropathy are characterized by sclerotic processes in the glomeruli. To elucidate the site, degree and time-honored changes of glomerular sclerosis, morphometric analysis was performed using the experimental animals models. Methods : The animals used were male Sprague-Dowley rats and separated into 4 groups as young mormal control, old control, streptozotocin-injected group, and right nephrectornized group. Chronologically kidney specimens were obtained after each treatment and processed to evaluated histologic changes. To evaluated the glomerular area, interstitial fibrosis and glomerular tuft fibrosis, the kidney specimens were fixed in Buin`s solution, paraffin-embedded and 2 ㎛ sections were Sirius red stained. To study the mesangial area, mesangial matrix area, glomerular basement membrane, and tubular basement membrane, the specimens were fixed in 2,5% glutaraldehyde, epon-embedded, double-stained and examined under the transmission electron microscope. All the specimens were analyzed morphometrically using the Image Pro Plus software. The obtained morphometric data were statistically analyzed to evaluate the differences of fibrotic processes and degree between experimental groups. Results : Diabetic group revealed statistically significant increase of glomerular area from 8th week after streptozotocin injection to 24th week of experimental date. The parenchymal fibrosis and glomerular tuft fibrosis was prominent from the 2nd week of injection and steadily increased until the end of experimental date. The thickness of glomerular basement membrane was significantly increased even at the first week of injection and the tubular basement membrane also increased in thickness at the 3rd week of experiment. Ablation nephropathy model made by right nephrectomy showed increased glomerular area at the 7th week of ablation and the degree were intensified after 16th week of experimental date. The amount of stainable collagen in the renal parenchyme and glomerular tuft increased in the second week kidney sample and steadily increased thereafter until the end of experimental date. The increase of thickness of GBM and TBM also started to appear at the second week of operation. The old control also revealed fibrosis but the degree was less than the diabetic and ablation groups. Both diabetic and ablation nephropathy groups exhibited extensive increase of glomerular area, stainable collagen, thickness of GBM and TBM at the end of experimental date and the ablation group revealed more extensive evidences of fibrosis without statistical significance. Comparison between the experimental groups were meaningless because the duration of the experimental manipulation was not the same. Conclusion: Glomerular and renal interstitial sclerosis and thickening of GBM and TBM are not the specific lesions of the diabetic glomerulopathy and are the common histologic changes occur in the kidney of partial parenchymal loss of any etiology. And it is suggested by this study that the common hemodynamic change involving the diabetic nephropathy, ablation nephropathy and physiologic aging is one of the important pathogenetic factors of glomerular sclerosis.

국내산 중하(Metapenaeus joyneri) 내 주알레르겐 규명 : 가열 및 소화액에 의한 변화

윤성호,김현아,김현미,최정희,서창희,남동호,김윤근,민경업,박해심 대한알레르기학회 2004 천식 및 알레르기 Vol.24 No.2

분화된 HL60 세포에서 Granulocyte - Macrophage Colony - Stimulating Factor 에 의한 95kDa 단백질의 Tyrosine 잔기 인산화

이영한,김정옥,민도식,김희숙,김용식,이창연,류성호,서판길 ( Young Han Lee,Jeong Ock Kim,Do Sik Min,Hee Sook Kim,Yong Sik Kim,Chang Youn Lee,Sung Ho Ryu,Pann Ghill Suh ) 생화학분자생물학회 1994 BMB Reports Vol.27 No.5

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) is a multipotent cytokine which stimulates the proliferation and differentiation of various lineage of hematopoietic cells. We examined whether GM-CSF stimulates protein phosphorylation in HL60 cells pretreated with differentiation-inducing factors such as PMA, 1,25-(OH)₂VD₃ and DMSO. GM-CSF induced tyrosine phosphorylation of 95 kDa protein in PMA- or 1,25-(OH)₂VD₃ but not in DMSO-pretreated cells. Tyrosine phosphorylation of 95 kDa was detected at 1 min and 2 min after stimulation of GM-CSF in PMA- and 1,25-(OH)₂VD₃-pretreated cells, respectively. Kinase activity which phosphorylates tyrosine residues) of the 95 kDa protein appeared to increase in a time dependent manner in PMA-pretreated cells, whereas the expression level of 95 kDa protein was not changed. We also observed that 95 kDa protein was autophosphorylated in immunecomplex kinase assay, suggesting that this 95 kDa protein may be tyrosine kinase which is activated in lineage specific manner. These results suggest that 95 kDa protein may be involved in an early signal transduction pathway of GM-CSF.

분화된 HL60 세포에서 Granulocyte-Macrophage Colony-Stimulating Factor에 의한 95 kDa 단백질의 Tyrosine잔기 인산화

이영한,김정옥,민도식,김희숙,김용식,이창연,류성호,서판길,Lee, Young-Han,Kim, Jeong-Ock,Min, Do-Sik,Kim, Hee-Sook,Kim, Yong-Sik,Lee, Chang-Youn,Ryu, Sung-Ho,Suh, Pann-Ghill 생화학분자생물학회 1994 한국생화학회지 Vol.27 No.5

사람의 granulocyte-macrophage colony-stimulating factor(GM-CSF)는 세포 표면에 존재하는 특이 수용체 자극을 통하여 각종 분화단계에 있는 골수세포의 성장과 분화에 중요한 cytokine이다. HL60 세포에 분화 유도 인자인 phorbol 12-myristate 13-acetate(PMA), $1{\alpha}$,25-dihydroxyvitamine $D_3$[1,25-$(OH)_{2}VD_{3}$] 및 dimethyl sulfoxide(DMSO) 등을 전처리한 후 GM-CSF 자극에 대해 특정 분화단계에서만 활성화되는 세포내 단백질을 조사하였다. SH2-SH3 domain을 인지하는 F7-2 항체로 면역 침전하여 면역 블롯한 결과 미분화 세포와 DMSO를 처리한 세포에서는 GM-CSF 자극에 의해 tyrosine 인산화되는 단백질을 발견할 수 없었지만, PMA와 1,25-$(OH)_2VD_3$를 전처리한 세포에서는 95kDa 단백질의 tyrosine 인산화가 일어남을 관찰하였다. Kinetics 분석결과 95 kDa 단백질의 tyrosine 인산화 반응은 GM-CSF 처리 후 1분 이내에, 1,25-$(OH)_{2}VD_{3}$를 전처리한 세포에서는 2분 이내에 나타나는 신속한 반응이었다. 이 단백질이 세포에서 발현되는 양은 PMA 전처리 시간에 무관하게 일정하였으나 GM-CSF에 의한 인산화는 PMA 전처리 시간에 따라 변화하였다. 또한, 95 kDa 단백질은 in vitro에서도 autophosphorylation되었다. 이러한 결과로부터 95 kDa 단백질은 PMA나 1,25-$(OH)_{2}VD_{3}$로 분화 유도된 HL60 세포에서 GM-CSF의 초기 신호전달 경로에 관여하고 있음을 추측할 수 있었다. Human granulocyte-macrophage colony-stimulating factor (GM-CSF) is a multipotent cytokine which stimulates the proliferation and differentiation of various lineage of hematopoietic cells. We examined whether GM-CSF stimulates protein phosphorylation in HL60 cells pretreated with differentiation-inducing factors such as PMA, 1,25-$(OH)_{2}VD_{3}$ and DMSO. GM-CSF induced tyrosine phosphorylation of 95 kDa protein in PMA- or 1,25-$(OH)_{2}VD_{3}$ but not in DMSO-pretreated cells. Tyrosine phosphorylation of 95 kDa was detected at 1 min and 2 min after stimulation of GM-CSF in PMA- and 1,25-$(OH)_{2}VD_{3}$-pretreated cells, respectively. Kinase activity which phosphorylates tyrosine residue(s) of the 95 kDa protein appeared to increase in a time dependent manner in PMA-pretreated cells, whereas the expression level of 95 kDa protein was not changed. We also observed that 95 kDa protein was autophosphorylated in immunecomplex kinase assay, suggesting that this 95 kDa protein may be tyrosine kinase which is activated in lineage specific manner. These results suggest that 95 kDa protein may be involved in an early signal transduction pathway of GM-CSF.

PEID를 利用한 中型 프레스의 設備總合效率 向上에 關한 硏究

徐昌敏,李文煥,徐德榮 경북대학교 산업기술연구소 1993 産業技術硏究誌 Vol.21 No.-

In recent years a serious interruption loss often occurs at highly expensive developed equipment. To maximize the total equipment efficiency of the Midium-Press it is essential to reveal and improve the potential loss of equipment based on these 6 kinds of chronic loss. Further, the way to minimize the investment in equipment has been presented by applying the PEID(Program for Equipment Improvement & Development).

작은 表面疲勞균열의 成長擧動에 關한 硏究

徐昌敏,李正州 경북대학교 공과대학 1984 工大硏究誌 Vol.13 No.-

In this paper, rotating bending fatigue tests have been carried out in three kinds of carbon steel specimen; an annealed low carbon steel, an annealed medium carbon steel, an annealed high carbon steel and quenched-tempered high carbon steel; with a small artificial defect that might exist in real structure. Fatigue crack lengths have been observed by a method of replication in order to investigate the growth behavior of fatigue crack in the view points of strength of matevials. The main results obtained are as follows: 1) The effect of a small surface defect upon the reduction of fatigue limit is considerably large, and the rate of fatigue limit reduction of surface defect with dlia 0.?? and depth 0.5mm is larger than the surface defect of 0.1mm. 2) When the growth rate of surface crack length (2 a) was investigated, growth rate of surface crack was not related with stress level and materials, and there exist the following relationships between da/dn and σ^n_a, ie surface crack length propagated from small surface crack can be expressed as da/dn = C.,σ^n_a.(a)