Tae Oh Kim

Stress distribution of three NiTi rotary files under bending and torsional conditions using a mathematic analysis

AIMnTo compare and evaluate the stress distribution of three NiTi instruments of various cross-sectional configurations under bending or torsional condition using a finite-element analysis model.nnnMETHODOLOGYnThree NiTi files (ProFile, ProTaper and ProTaper Universal) were scanned using Micro-CT to produce a three-dimensional digital model. The behaviour of the instrument under bending or torsional loads was analysed mathematically in software (ABAQUS V6.5-1), taking into consideration the nonlinear mechanical characteristic of NiTi material.nnnRESULTSnProFile showed the greatest flexibility, followed by ProTaper Universal and ProTaper. The highest stress was observed at the surface near the cutting edge and the base of (opposing) flutes during cantilever bending. Concentration of stresses was observed at the bottom of the flutes in ProFile and ProTaper Universal instruments in torsion. The stress was more evenly distributed over the surface of ProTaper initially, which then concentrated at the middle of the convex sides when the amount of angular deflection was increased.nnnCONCLUSIONnIncorporating a U-shaped groove in the middle of each side of the convex-triangular design lowers the flexural rigidity of the origin ProTaper design. Bending leads to the highest surface stress at or near the cutting edge of the instrument. Stress concentration occurs at the bottom of the flute when the instrument is subjected to torsion.

Gastroesophageal flap valve is associated with gastroesophageal and gastropharyngeal reflux

BackgroundThe endoscopic grade of the gastroesophageal flap valve (GEFV) is suggested to be a good predictor of reflux status. The aim of this study was to investigate the association of the GEFV and gastroesophageal and gastropharyngeal reflux.MethodsA total of 364 patients (151 men and 233 women; mean age, 52.2 years) who underwent endoscopy, esophageal manometry, and ambulatory 24-h dual-probe pH monitoring were included. GEFV was graded I through IV using Hill’s classification; then, GEFV was classified into two groups: a normal GEFV group (grades I and II) and an abnormal GEFV group (grades III and IV). Findings of endoscopy, esophageal manometry, and ambulatory pH monitoring were compared between the groups.ResultsIncreased GEFV grade was significantly associated with an increased prevalence of both reflux esophagitis and Barrett’s epithelium (P < 0.001). Lower esophageal sphincter pressure was significantly lower in the abnormal GEFV group than in the normal GEFV group (P < 0.001). All variables showing gastroesophageal reflux in the distal probe were significantly higher in the abnormal GEFV group than in the normal GEFV group (P < 0.001). In addition, all variables, except the supine time of pH < 4, showing gastropharyngeal reflux in the proximal probe were significantly higher in the abnormal GEFV group than in the normal GEFV group (P < 0.001). The frequency of gastroesophageal reflux disease and of gastropharyngeal reflux disease was significantly higher in the abnormal GEFV group than in the normal GEFV group (P < 0.001).ConclusionEndoscopic grading of the GEFV is easy and provides useful information about the status of gastroesophageal and gastropharyngeal reflux.

Rebampide enema therapy as a treatment for patients with chronic radiation proctitis: initial treatment or when other methods of conservative management have failed

IntroductionRadiation proctitis is a common complication following radiation therapy for pelvic malignancies. There have been no formal trials of treatment for radiation proctitis and a variety of methods are currently used. We assessed the efficacy of rebamipide enema to control symptoms and proctoscopic findings from radiation proctitis.Materials and methodsFifteen patients with radiation proctitis were enrolled. Enemas containing 150xa0mg rebamipide per dosing were administered after morning bowel movement, and always prior to bedtime, twice daily for 4xa0weeks. The efficacy of treatment was assessed from clinical symptoms (Subjective Objective Management Analysis Scale for Rectal Toxicity) and endoscopic findings.ResultsThe mean bleeding score improved from 2.67 to 0.53 (Pu2009<u20090.01). The mean symptom scores improved in those patients who had pain (0.40 to 0.13), tenesmus (0.40 to 0.20), and stool frequency (0.27 to 0.13). The mean improvement in telangiectasia scores (2.13 to 0.80, Pu2009<u20090.01), bleeding point scores (1.80 to 0.27, Pu2009<u20090.01), and friable mucosa scores (1.33 to 0.20, Pu2009<u20090.01) were all statistically significant. No side effects were noted in any patients.ConclusionRebamipide enema therapy for radiation proctitis is a safe and effective treatment of radiation proctitis. We suggest the value of rebamipide enema in the treatment of radiation proctitis when other conservative management or first treatment has failed.

Analysis of Endoscopic Electronic Image of Intramucosal Gastric Carcinoma Using a Software Program for Calculating Hemoglobin Index

Hemoglobin is the predominent pigment in the gastrointestinal mucosa, and the development of electronic endoscopy has made it possible to quantitatively measure the mucosal hemoglobin volume, by using a hemoglobin index (IHb). The aims of this study were to make a software program to calculate the IHb and then to investigate whether the mucosal IHb determined from the electronic endoscopic data is a useful marker for evaluating the color of intramucosal gastric carcinoma with regard to its value for discriminating between the histologic types. We made a software program for calculating the IHb in the endoscopic images. By using this program, the mean values of the IHb for the carcinoma (IHb-C) and those of the IHb for the surrounding non-cancerous mucosa (IHb-N) were calculated in 75 intestinal-type and 34 diffuse-type intramucosal gastric carcinomas. We then analyzed the ratio of the IHb-C to the IHb-N (C/N ratio). The C/N ratio in the intestinal-type carcinoma group was higher than that in the diffuse-type carcinoma group (p<0.001). In the diffuse-type carcinoma group, the C/N ratio in the body was lower than that in the antrum (p=0.022). The accuracy rate, sensitivity, specificity, and the positive and negative predictive values for the differential diagnosis of the diffuse-type carcinoma from the intestinal-type carcinoma were 94.5%, 94.1%, 94.7%, 88.9% and 97.3%, respectively. IHb is useful for making quantitative measurement of the endoscopic color in the intramucosal gastric carcinoma, and the C/N ratio by using the IHb would be helpful for distinguishing the diffuse-type carcinoma from the intestinal-type carcinoma.

Perivascular Epithelioid Cell Tumor (PEComa) of Abdominal Cavity from Falciform Ligament: A Case Report

We present a case of perivascular epithelioid cell tumors (PEComas) in the abdominal cavity at the falciform ligament. A 30-yr-old Korean man visited to hospital for the evaluation of a growing, palpable abdominal mass. He had felt the mass growing over 6 months. There was no family or personal history of tuberous sclerosis. The resected specimen showed a mass of 8.0×7.0×5.5 cm in size. Histological examination showed sheets of spindle-to-epithelioid cells with clear-to-eosinophilic cytoplasm. Immunohistochemically, tumor cells were positive for HMB-4 (gp100) and smooth muscle actin. They were also positive for the S-100, which is a marker of neurogenic and melanocytic tumors. Patient was treated with radical resection of tumor without any adjuvant therapy. He is well and on follow-up visits without tumor recurrence.