GT rotary file을 이용한 만곡 근관형성시 작업 효율 및 file 변형 발생에 관한 연구

신주희,백승호,배광식,임성삼,윤수한,김병현 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.5

Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal. However, as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore, in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nitckel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature of root canal and reducing the deformation of root canal. However, it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150∼350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g, 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1.Analysis of the experiment results revealed that the tome spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range (β-weight test) . 2.Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease, In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of◎eater tier◎cal forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3.Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block. Key words : GT rotary file, Crown-down method, Working efficiency, Vertical force, Rpm, Deformation and breakage of file

How Should We Classify Patients Who Have Spondylitis and Psoriasis?

Baek Han Joo 대한의학회 2022 Journal of Korean medical science Vol.37 No.33

강직척추염 환자에서의 수면장애

백한주 ( Han Joo Baek ) 대한류마티스학회 2014 대한류마티스학회지 Vol.21 No.6

신(新)의료전문가주의

백한주 ( Han Joo Baek ) 대한류마티스학회 2012 대한류마티스학회지 Vol.19 No.6

통풍성 관절염의 임상 양상에 관한 연구

백한주(Han Joo Baek),이은봉(Eun Bong Lee),유창달(Chang Dal Yoo),김현아(Hyun An Kim),송영욱(Yeong Wook Song),임용성(Yong Seong Lim) 대한내과학회 1997 대한내과학회지 Vol.52 No.6

N/A Objectives: The aim of this study is to enhance understanding the clinical features, pathogenesis, diagnosis and treatment of gouty arthritis in Korea by analyzing the clinical manifestations of the patients with urate crystal-proven gouty arthritis. Methods: 78 cases who had been diagnosed as gouty arthritis by confirming the urate crystals in synovial fluids or tophi in Seoul National University Hospital between January 1, 1989 and July 31, 1995 were analysed for their histories, symptoms, signs, laboratory data, and X-ray findings. Results: 1) Male to female ratio was 18.5:1. The mean age of onset is 49.3±14.5 years(range 11-83 years); the mean duration of disease 6.5±7.0 years(range 0-30 years); the mean duration of gouty attack 7.2±5.5 days(range 1-30 days). 2) The frequent precipitating factors of gouty arthritis were hospitalization(37%) and alcohol drinking(15%). The most frequent accompanying disease was hypertension(24%). Obesity, diabetes, chronic renal failure, hyperlipidemia, ischemic heart diseases, or cerebrovascular diseases were also accompanied by gouty arthritis. 3) The patterns of joint involvement were devided into 3 groups: monoarthritis; 42%, oligoarthritis; 35%, polyarthritis; 23%, The most frequent site of the first gouty attack was the 1st toe(65%). The most frequently involved joint at gouty attack was also the 1st toe(68%). While only lower extremities were involved in most cases with monoarthritis and oligoarthritis(91% and 78%, respectively), both lower and upper extremities were involved in most cases with polyarthritis(78%). 4) Hyperuricemia was found in 74% of the cases at gouty attack. But serum uric acid level was normal in 26%. With respect to pathogenesis of hyperuricemia, 14% of the cases had uric acid overproduction and 86% had uric acid underexcretion. 5) Bony changes in radiologic findings were found in 47% of the cases and tophi in 33%. Bony changes and tophi was significantly related to the younger age of gouty onset and higher serum uric acid level at gouty attack. 6) Acute gouty arthritis responded well to colchicine and NSAIDs. There was no difference in efficacy and the frequency of side effects between them. Conclusion: The clinical features of the gouty arthritis in Korea showed no difference from those in foreign studies except higher prevalence of oligo-/polyarthritis and tophi. To be remarkable, 26% of the patients with gouty arthritis did not have hyperuricemia at gouty attack. This finding indicates that urate crystals should be confirmed by synovial fluid examination for diagnosis of gouty arthritis.

건선 관절염의 빈도 및 임상 양상에 관한 연구

백한주 ( Han Joo Baek ),유창달 ( Chang Dal Yoo ),신기철 ( Ki Chul Shin ),이윤종 ( Yun Jong Lee ),강성욱 ( Seong Wook Kang ),이은봉 ( Eun Bong Lee ),한창완 ( Chang Wan Han ),김현아 ( Hyun Ah Kim ),송영욱 ( Yeong Wook Song ),윤재일 대한류마티스학회 1998 대한류마티스학회지 Vol.5 No.2

Objective: To evaluate the prevalence of psoriatic arthritis(PsA) in Korean patients with psoriasis and to determine the clinical features of PsA. Methods: We examined 356 patients with psoriasis who visited dermatology clinic in Seoul National University Hospital between January 1 and April 28, 1997. Thirty-two patients were determined to have PsA. Nineteen cases of PsA, who were diagnosed in rheumatology clinic of the same hospitial from January 1983 to November 1997, were added to these patients and total 51 cases of PsA were analysed for clinical, laboratory and radiologic features. Results: The prevalence of PsA among patients with psoriasis was 9%(32/356). Male to female ratio of psoriatic arthritis was 1.1:1. Median age at onset of psoriatic arthritis was 34.5 years(range 9-63 years) and mean duration of psoriatic arthritis was 5.8±6.0 years. Psoriasis preceded arthritis in 73.5% of subjects, arthritis preceding psoriasis in 14.3%. Silmultaneous onset of both joint and skin disease was found in 12.2% of subjects. Nail changes, dactylitis and enthesopathy were detected in 37.1%, 21.6% and 33.3% of patients with PsA, respectively. Frequently involved joints in PsA were sacroiliac joints(51%), knees(49%), proximal interphalangeal joints of hands(33.3%), ankles(25.5%). About thirteen percent of patients with PsA were in ACR functional class III/IV. Patients with PsA were older than those with psoriasis alone(39 vs 35 [years], p=0.034). There were no significant differences between patients with PsA and those with psoriasis alone in age at onset of psoriasis, duration, family history, nail involvement, initial extent or type of psoriasis. Higher prevalence of anemia, leukocytosis, and increased ESR was found in patients with PsA compared to psoriasis alone(26% vs 6.3%, 28% vs 5%, and 40% vs 10.3%, p<0.001, respectively). ANA positivity and radiologic sacroiliitis were more frequent in patients with PsA than those with psoriasis alone(35.7% vs 16.7%, p=0.015 and 45.5% vs 1.1%, p=0.001, respectively). Patterns of PsA according to Moll and Wright criteria were as follows: spondylitis was present in 54.9% of patients; oligoarthritis in 25.5%, polyarthritis in 9.8%, predominant DIP involvement in 5.9%. Three cases of SAPHO syndrome were also found in our series. Age at onset of psoriasis and arthritis in spondylitis group was significantly lower than that in non-spondylitis group(23 vs 30 and 28 vs 44 [years], p<0.05, respectively). HLA-B27 was more prevalent in patients with PsA and spondylitis group compared to normal Koreans(19.5% vs 5.7%, p=0.024 and 29.2% vs 5.7%, P=0.0027, respectively), but HLA-B27 was not increased in non-spondylitis group. Conclusions: The clinical features of PsA in our series showed some differences from previous reports. Spondylitis was the commonest pattern of PsA. Nail changes and enthesopathy were less common compared to previous reports. Anemia, leukocytosis, increased ESR, ANA positivity, and radiologic sacroiliitis were more frequent in patients with PsA than in those with psoriasis alone. Age at onset of psoriasis and arthritis in spondylitis group was significantly lower than that in non-spondylitis group. The prevalence of HLA-B27 was increased in patients with PsA, especially in spondylitis group.

Protection of Human Fibroblasts from Reactive Oxygen Species by Green Tea Polyphenolic Compounds

Han, Dong Wook,Kim, H.H.,Son, Hyun Joo,Baek, Hyun Sook,Lee, Kwon Yong,Hyon, Suong Hyu,Park, Jong Chul Trans Tech Publications, Ltd. 2005 Key Engineering Materials Vol.288 No.-

<P>The potential protective roles played by green tea compounds (GTPCs) against reactive oxygen species-induced oxidative stress in cultured fetal human dermal fibroblasts (fHDFs) were investigated according to cell viability measurement methods, such as fluorescence double staining followed by flow cytometry (FCM), MTT assay and crystal violet uptake. Oxidative stress was induced in the fHDFs, either by adding 50 mM H2O2 or by the action of 40 U/L xanthine oxidase (XO) in the presence of xanthine (250 µM). FCM analysis was the most suitable to show that both treatments produced a significant (p < 0.05) reduction in the fHDF viability, attributed to its high sensitivity. On the microscopic observations, the cell death with necrotic morphology was appreciably induced by both treatments. These oxidative stress-induced damages were significantly (p < 0.05) prevented by pre-incubating the fHDFs with 200 µg/ml GTPC for 1 h. These results suggest that GTPC can act as a biological antioxidant in a cell culture experimental model and prevent oxidative stress-induced cytotoxicity in cells.</P>

Inhibitory Activity of Bumblebee Worker (Bombus terrestris L.) Venoms on Nitric Oxide, TNF-${\alpha}$ and IL-6 Production in Lipopolysaccharide-Activated Macrophages

Han Sang-Mi,Lee Kwang-Gill,Yeo Joo-Hong,Kweon Hae-Yong,Woo Soon-Ok,Yoon Hyung-Joo,Baek Ha-Ju,Park Kwan-Kyu Korean Society of Sericultural Science 2006 International Journal of Industrial Entomology Vol.12 No.2

To elucidate the composition of bumblebee (Bomb us terrestris) venom (BBV) and the anti-inflammatory effect of BBV. The major components of BBV by LC chromatography and SDS-PAGE were identified. The production of nitric oxide (NO) and proinflammatory cytokines was examined by lipopolysaccharide (LPS) in a macrophage cell line, RAW 264.7 cells, with BBV. BBV inhibits LPS-induced NO in a dose dependent manner. We also found that BBV inhibits proinflammatory cytokine, tumor necrosis factor (TNF)-${\alpha}$ and interleukin (IL)-6 production. These findings mean that BBV can be used in controlling macrophages mediated inflammation related disease. Additional studies on the pharmacological aspects of the individual components of BBV are recommended for future trials.

Antibacterial Activity of the Honey Bee Venom against Bacterial Mastitis Pathogens Infecting Dairy Cows

Han, Sang-Mi,Lee, Kwang-Gill,Yeo, Joo-Hong,Kweon, Hae-Yong,Kim, Bong-Soon,Kim, Jae-Myung,Baek, Ha-Ju,Kim, Soon-Tae Korean Society of Sericultural Science 2007 International Journal of Industrial Entomology Vol.14 No.2

The antibacterial activity of Korean honey bee venom (KBV) was examined against seven major bacterial mastitis pathogens, Enterococcus faecium, Escherichia coli, Methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus intermedius, Streptococcus oralis and Streptococcus uberis isolated from infected mammary quarters of cows. Seven bacterial mastitis pathogens were studied for antibacterial activity of the KBV by disc diffusion assay, minimal inhibitory concentrations (MIC) and bacterial count in milk samples. The KBV showed activity against Ent. faecium, E. coli, MRSA, Staph. aureus, Strep. intermedius. The order of susceptibility of the bacteria against the KBV was Staph. aureus>MRSA>E. coli>Strep. intermedius>Ent. faecium>Strep. oralis>Strep. uberis. The MIC against Staph. aureus, MRSA and E. coli were stronger effect as compared with standard drug. The effect of the KBV ($100{\mu}g\;ml^{-1}$) on the viability of Ent. faecium, E. coli, MRSA, Staph. aureus, Strep. intermedius, Strep. oralis and Strep. uberis in milk differed significantly with each other within 12 h incubation period. The results indicate that KBV has significant antibacterial effects against major bacterial mastitis bacteria, Ent. faecium, E.coli, MRSA, Staph. aureus, Strep. intermedius. Results of the study indicate the potential use of KBV as alternative to antibiotic therapy. Further investigations are needed though to confirm its efficacy and its effects on the animals.

Enzymatic Saccharification and Ethanol Production of Food Waste using Saccharomyces cerevisiae KA4

Baek Rock Oh,Jung Kon Kim,Gui Hwan Han,Joo Young Son,Si Wouk Kim 한국생물공학회 2007 한국생물공학회 학술대회 Vol.2007 No.4