This in vitro study examined the effect of surface defects on cutting blades on the extent of the cyclic fatigue fracture of HEROShaper Ni-Ti rotary files using fractographic analysis of the fractured surfaces. A total of 45 HEROShaper (MicroMega) Ni-Ti rotary files with a #30/.04 taper were divided into three groups of 15 each. Group 1 contained new HEROShapers without any surface defects. Group 2 contained HEROShapers with manufacturing defects such as metal rollover and machining marks. Group 3 contained HEROShapers that had been clinically used for the canal preparation of 4-6 molars. A fatigue-testing device was designed to allow cyclic tension and compressive stress on the tip of the instrument whilst maintaining similar conditions to those experienced in a clinic. The level of fatigue fracture time was measured using a computer connected the system. Statistical analysis was performed using a Tukey's test. Scanning electron microscopy (SEM) was used for fractographic analysis of the fractured surfaces. The fatigue fracture time between groups 1 and 2, and between groups 1 and 3 was significantly different (p < 0.05) but there was no significant difference between groups 2 and 3 (p > 0.05). A low magnification SEM views show brittle fracture as the main initial failure mode. At higher magnification, the brittle fracture region showed clusters of fatigue striations and a large number of secondary cracks. These fractures typically led to a central region of catastrophic ductile failure. Qualitatively, the ductile fracture region was characterized by the formation of microvoids and dimpling. The fractured surfaces of the HEROShapers in groups 2 and 3 were always associated with pre-existing surface defects. Typically, the fractured surface in the brittle fracture region showed evidence of cleavage (transgranular) facets across the grains, as well as intergranular facets along the grain boundaries. These results show that surface defects on cutting blades of Ni-Ti rotary files might be the preferred sites for the origin of fatigue fracture under experimental conditions. Furthermore, this work demonstrates the utility of fractography in evaluating the failure of Ni-Ti rotary files.
Edible Grain ; Fatigue* ; Fractures, Stress* ; Microscopy, Electron, Scanning ; Molar

Truncus arteriosus is a rare congenital heart disease which is diagnosed in from 1 to 2 percent of congenital cardiac birth. Whithout surgical intervention, survival beyond infancy is unusual. Unoperated patients who survive to adult life have associated pulmonary stenosis or have developed pulmonary arteriolar disease. We report a case of truncus arteriosus in a 17-year-old man with a review of literature.
Adolescent ; Adult ; Heart Defects, Congenital ; Humans ; Parturition ; Pulmonary Valve Stenosis ; Truncus Arteriosus*

BACKGROUND/AIMS: Hepatic fibrosis in rat induced by thioacet amide shares similar morphological and biochemical characteristics with human liver cirrhosis. Thioacetamide (T AA) initially induces accumulation of collagen in Disse space and eventually leads to macro- and micronodular cirrhos is. Ito cell was believed to play a main role in hepatic fibrosis. And it s activity was known to be regulated by the expression of various genes. But little has been discovered about the upstream signal trans duction pathway of these genes in hepatic fibrosis. The expression of genesrelated to Ito cell activity was regulated by many transcription factors , the activity of which was regulated by protein kinase C( PKC) is oforms. So it is s upposed that PKC could be as s ociated with fibrosis in liver. METHODS: We investigated the correlation of PKC is oforms and It ocell activity in the course of hepatic fibrosis using TAA induced rat liver cirrhosis model. We used six week- old male rats , and administered 0.03% TAA in drinking water. The animals were sacrificed at 9, 20, and 30 weeks after TAA administration. The degree of hepatic fibrosis was evaluated by measuring the total amount of collagen.-SMA immunohist ochemical st aining of liver tissue was done to determine the Ito cell activity. The expression pattern of PKC isoforms was investigated by West ern blotting. RESULTS: In TAA- treated group, collagen cont ent and Ito cell activity did not increase until 30 weeks and 20 weeks of treatment , respectively, while in control group collagen cont ent and Ito cell activity were not detected. Collagen content showed linear correlation with Ito cell activity. This implied that the proliferation of activated Ito cells was prior to the increase of collagen content. In view of expression pattern of PKC is oforms, PKC alpha showed no difference in TAA- treated group and control group. In TAA-treated group, PKCbeta1 exhibited increased level of expression in both particulate and cytosolic forms at 9 weeks, while PKCdelta and PKC epsilon showed striking shift to particulated form. After 20 weeks, all of the PKC beta1, delta, and epsilon degenerated and showed remarkably decreased level of expression. This suggested PKC alpha had no relation to hepatic fibrosis,while PKC beta1, delta, and epsilon, showing activity at 9 weeks, were related to fibrosis og liver. In response to fibrogenic factors, molecules engaged in intracellular signal transduction pathway like PKC beta1, delta, and epsilon, began to change prior to the increase of Ito cell activity, morphologic changes and alterations of collagen content. CONCLUSION: Our results strongly suggest that the activity of PKC isoforms play an important role in early step of hepatic fibrosis, while accompanying Ito cell activity do in later step.
Animals ; Collagen ; Cytosol ; Drinking Water ; Fibrosis ; Hepatic Stellate Cells ; Humans ; Liver Cirrhosis* ; Liver* ; Male ; Protein Isoforms ; Protein Kinase C-epsilon ; Protein Kinases ; Rats ; Signal Transduction ; Strikes, Employee ; Thioacetamide ; Transcription Factors

Drug-induced acute interstitial nephritis is characterized by renal interstitial inflammatory cell infiltration and commonly presents as acute renal failure. This is caused mainly by methicillin, non-steroidal antiinflammatory drugs, sulfonamide diuretics such as thiazide, but cases induced by furosemide are rare. We report a patient with acute interstitial nephritis causing reversible acute renal failure and dermatitis while she was taking furosemide. A 37-year old woman was referred to our hospital because of generalized skin rash and non-oliguric acute renal failure. She had peripheral eosinophilia (1,577/mm3) and serum creatinine level of 6.8mg/dL. Skin biopsy showed leukoclastic vasculitis and percutaneous renal biopsy showed severe interstitial infiltration of lymph ocyte and mild interstitial fibrosis with focal tubular atrophy. After withdrawal of furosemide, renal function and skin lesions were completely recovered.
Acute Kidney Injury ; Adult ; Atrophy ; Biopsy ; Creatinine ; Dermatitis ; Diuretics ; Eosinophilia ; Exanthema ; Female ; Fibrosis ; Furosemide* ; Humans ; Methicillin ; Nephritis, Interstitial* ; Skin ; Vasculitis

PURPOSE: In the analysis of risk factors affecting the renal graft survival and graft function, time-dependent effect of each risk factor should be differentiated from net effect of risk factor. We attempted to analyze the impact of immunologic and/or non-immunologic risk factors on the graft function and survival after renal transplantation among the recipients having same immunologic risks at the time of transplantation. METHODS: Three hundred ninety recipients who underwent haplotype matched living related donor kidney transplantation and have been regularly followed-up were retrospectively evaluated in a single center. All recipients were treated with cyclosporine-based double or triple regimens. The graft function was evaluated by serum creatinine (Scr) level and 24 hours urinary excretion of protein every year until 5 years after transplantation. The donor kidney weight/ recipient body weight ratio (KW/BW), donor age/ recipient age ratio (DA/RA), donor-recipient sex (D-R sex) relationship, and episodes of acute rejection (AR) within 1 year were regarded as the potential risk factors affecting the graft survival and function in this study. Kaplan-Meier method and Cox proportional-hazard model were used for survival analysis. ANOVA to evaluate time-point difference of graft function, and repeated measures ANOVA to evaluate the yearly difference of graft function were used. RESULTS: Only the episode of AR was a significant risk factor affecting the graft survival. However, each non-immunologic risk factors (KW/BW, DA/RA, D-R sex) and AR episode persistently showed statistically significant impact on Scr level until 5 years after transplantation. Recipients having lowest KW/BW (1st Q KW/BW) and highest DA/RA (4th Q DA/RA) had experienced accelerated increment of Scr level from 4th year after transplantation. From 3rd year after transplantation, there is a significant correlation between the numbers of non-immunologic risk factor the recipients having had and yearly increment of Scr level. However, episode of AR didn't influence the annual slope of Scr level even 4th year after transplantation. CONCLUSIONS: Non-immunologic risk factors had an detrimental effect on renal graft function, especially from 3rd year after transplantation. To have a better long-term graft function, non-immunologic risk factors should be considered from the time of live donor evaluation for transplantation. From the early period of transplantation, the recipients should be aware of the negative impact of overweight in terms of graft function and other metabolic derangement.
Body Weight ; Creatinine ; Graft Survival* ; Haplotypes* ; Humans ; Kidney ; Kidney Transplantation ; Living Donors* ; Overweight ; Retrospective Studies ; Risk Factors ; Tissue Donors ; Transplantation* ; Transplants*

Gastrointestinal stromal tumors (GISTs) are the most common subepithelial tumor of the gastrointestinal tract. They originate from mesenchymal tissue. Because of difficulties in discriminating between benign and malignant GISTs, the treatment modality is selected on the base of tumor size, mitosis count, location, originating layer, and the presence of complications. Regular follow-up, open resection, or laparoscopic operation were considered main treatments for GISTs. Surgical resection is standard treatment for a huge GIST. However, the treatment method is not determined for GISTs of less than 3 cm that show a benign clinical course. Recently, endoscopic treatment was attempted because of recent endoscope developments and associated devices. We report three cases of gastric GISTs with a high risk of aggressive behavior that were successfully treated by endoscopic resection.
Endoscopes ; Follow-Up Studies ; Gastrointestinal Stromal Tumors ; Gastrointestinal Tract ; Mitosis

OBJECTIVE: Differentiation of demyelination in white matter from axonal damage can be determined using diffusion tensor imaging (DTI). In this study using meningioma patients an attempt was made to evaluate the relationship between preoperative weakness and the changes of diffusion parameters in the corticospinal tract (CST) using DTI. METHODS: Twenty-six patients with meningioma were enrolled in this study. Eleven of them suffered from objective motor weakness and were classified as Group 1. The remaining 15 patients did not present motor weakness and were classified as Group 2. Fiber tractography and CST diffusion parameters were obtained using DTIStudio. The ratios (lesion side mean value/contralateral side mean value) of CST diffusion parameters were compared with 1.0 as a test value using a one-sample t-test. RESULTS: In Group 1, fractional anisotropy (FA), tensor trace (TT), and radial diffusivity (RD, lambda2 and lambda3) of the CST were significantly different between two hemispheres, but axial diffusivity (AD, lambda1) of the CST was not significantly different between two hemispheres. In Group 2, FA and lambda3 of CST did not differ significantly between the hemispheres. In Group 2, TT, lambda1, and lambda2 of CST in the ipsilateral hemisphere were significantly higher than those of the unaffected hemisphere. However, the differences were small. CONCLUSION: Motor weakness was related to a low FA and high TT resulting from increased RD of the CST fibers. CST diffusion changes in patients with weakness are similar to those for demyelination.
Anisotropy ; Axons ; Demyelinating Diseases* ; Diffusion Tensor Imaging* ; Diffusion* ; Humans ; Meningioma* ; Pyramidal Tracts*

Adding to the previous reports about the infectious complications in renal transplant recipients in azathioprine era, we conducted this retrospective study to analyse the incidence and pattern of posttransplant infections in cyclosporin era and its impact on graft and patient survival. Among 482 patients who performed renal transplantation (tpl) from Mar. 1985 to Dec. 1997 at Seoul National University Hospital, 133 infections developed in 105 patients (21.8% incidence). These infections were grouped into 3 categories; Perioperative (infection within first month after tpl: N=19), Early (infection between 1 to 6 months after tpl: N=24), and Late (infection more than 6 months after tpl: N=87). According to the anatomical site of infection, skin (49 cases) was the most common site of infection, followed by lung (36), oropharynx (13), urinary tract (12). Regarding the etiologic organisms of microbiologically documented 108 infections, viral infections were most common (60.2%), followed by bacterial (22.2%), fungal (14.8%), and others (2.8%). In viral infections, Varicella zoster virus infection was most common (58%). Bacterial infections included 12 Mycobacteral infections, 10 Gram (-), and 2 Gram (+) bacterial infections. In fungal infections, tinea was most common in 8 cases, followed by candidiasis in 3, cryptococcosis in 2, and aspergillosis in 1. Incidence of rejection episode was statistically higher in patients with infection than those without infection (40.0% vs 28.4%; p=0.023). Among 28 mortalities, infection-related deaths were 7. In conclusion, aggressive diagnostic strategies including invasive procedures to characterize the organisms and specific treatment is the best way to reduce the morbidity and mortality.
Aspergillosis ; Azathioprine ; Bacterial Infections ; Candidiasis ; Cryptococcosis ; Cyclosporine* ; Herpesvirus 3, Human ; Humans ; Incidence ; Kidney Transplantation* ; Lung ; Mortality ; Opportunistic Infections ; Oropharynx ; Retrospective Studies ; Seoul ; Skin ; Tinea ; Transplantation ; Transplants ; Urinary Tract

BACKGROUND: Nosocomial candidemia has increased over the past 2 decades. The rank order of occurrence and antifungal resistance profiles of the various species of Candida causing candidemia is important in establishing empiric treatment protocols. METHODS: We investigated antifungal susceptibilities and distribution of Candida species recovered from blood cultures over an 8-year period in Chonnam National University Hospital. The results obtained from the period 1994 through 1997 (period 1) were compared with those from the period 1998 through 2001 (period 2). Minimal inhibitory concentrations (MICs) of amphotericin B, fluconazole and itraconazole for each isolate were determined by the NCCLS broth microdilution method. RESULTS: During an 8-year period, 805 strains of Candida species were isolated from 290 patients. In period 1, the Candida species recovered most frequently from candidemic patients was C.albicans(29.5%), followed by C. parapsilosis (25.9%) and C. tropicalis (18.8%). In period 2, C. parapsilosis (31.5%) was the most common species, followed by C. albicans (23.6%), and C.glabrata (14.0%). These data, compared to those of period 1, indicate a variation in species distribution, with the proportions of C. glabrata increasing by 10.0% (P<0.005). MIC50 of amphotericin B, fluconazole and itraconazole for each species did not change appreciably during the two periods. However, resistance to fluconazole (>or=64 microgram/mL) and itraconazole (>or=1 microgram/mL) was observed more frequently in period 2 (8.0% and 20.9%, respectively) than in period 1 (2.0% and 7.0%, respectively)(P<0.05). CONCLUSIONS: These data showed that MICs of amphotericin B, fluconazole and itraconazole for each species did not change during the 8-year span, but azole resistant Candida species such as C. glabrata, increased in the latter four years (period 2).
Amphotericin B ; Candida* ; Candidemia ; Clinical Protocols ; Danazol ; Fluconazole ; Humans ; Itraconazole ; Jeollanam-do

BACKGROUND: Nosocomial candidemia has increased over the past 2 decades. The rank order of occurrence and antifungal resistance profiles of the various species of Candida causing candidemia is important in establishing empiric treatment protocols. METHODS: We investigated antifungal susceptibilities and distribution of Candida species recovered from blood cultures over an 8-year period in Chonnam National University Hospital. The results obtained from the period 1994 through 1997 (period 1) were compared with those from the period 1998 through 2001 (period 2). Minimal inhibitory concentrations (MICs) of amphotericin B, fluconazole and itraconazole for each isolate were determined by the NCCLS broth microdilution method. RESULTS: During an 8-year period, 805 strains of Candida species were isolated from 290 patients. In period 1, the Candida species recovered most frequently from candidemic patients was C.albicans(29.5%), followed by C. parapsilosis (25.9%) and C. tropicalis (18.8%). In period 2, C. parapsilosis (31.5%) was the most common species, followed by C. albicans (23.6%), and C.glabrata (14.0%). These data, compared to those of period 1, indicate a variation in species distribution, with the proportions of C. glabrata increasing by 10.0% (P<0.005). MIC50 of amphotericin B, fluconazole and itraconazole for each species did not change appreciably during the two periods. However, resistance to fluconazole (>or=64 microgram/mL) and itraconazole (>or=1 microgram/mL) was observed more frequently in period 2 (8.0% and 20.9%, respectively) than in period 1 (2.0% and 7.0%, respectively)(P<0.05). CONCLUSIONS: These data showed that MICs of amphotericin B, fluconazole and itraconazole for each species did not change during the 8-year span, but azole resistant Candida species such as C. glabrata, increased in the latter four years (period 2).
Amphotericin B ; Candida* ; Candidemia ; Clinical Protocols ; Danazol ; Fluconazole ; Humans ; Itraconazole ; Jeollanam-do