Effects of diallyl sulfide (DAS) on thioacetamide-induced hepatotoxicity and immunotoxicity were investigated. When male Sprague-Dawley rats were treated orally with 100, 200 and 400 mg/kg of DAS in corn oil for three consecutive days, the activity of cytochrome P450 (CYP) 2E1-selective p-nitrophenol hydroxylase was dose-dependently suppressed. In addition, the activities of CYP 2B-selective benzyloxyresorufin O-debenzylase and pentoxyresorufin O-depentylase were significantly induced by the treatment with DAS. Western immunoblotting analyses also indicated the suppression of CYP 2E1 protein and/or the induction of CYP 2B protein by DAS. To investigate a possible role of metabolic activation by CYP enzymes in thioacetamide-induced hepatotoxicity, rats were pre-treated with 400 mg/kg of DAS for 3 days, followed by a single intraperitoneal treatment with 100 and 200 mg/kg of thioacetamide in saline for 24 hr. The activities of serum alanine aminotransferase and aspartate aminotransferase significantly elevated by thioacetamide were protected in DAS-pretreated animals. Likewise, the suppressed antibody response to sheep erythrocytes by thioacetamide was protected by DAS pretreatment in female BALB/c mice. Taken together, our present results indicated that thioacetamide might be activated to its toxic metabolite(s) by CYP 2E1, not by CYP 2B, in rats and mice.
Alanine Transaminase ; Animals ; Antibody Formation ; Aspartate Aminotransferases ; Biotransformation ; Blotting, Western ; Corn Oil ; Cytochrome P-450 CYP2E1* ; Cytochrome P-450 Enzyme System ; Erythrocytes ; Female ; Humans ; Male ; Mice ; Rats ; Rats, Sprague-Dawley ; Sheep ; Thioacetamide

Background/Aims: This study aimed to evaluate the cost-effectiveness of hepatitis C virus (HCV) screening compared to no screening in the Korean population from societal and healthcare system perspectives. Methods: A published decision-tree plus Markov model was used to compare the expected costs and quality-adjusted life years (QALY) between one-time universal HCV screening and no screening in the population aged 40–65 years using the National Health Examination (NHE) program. Input parameters were obtained from analyses of the National Health Insurance claims data, Korean HCV cohort data, or from the literature review. The population aged 40–65 years was simulated in a model spanning a lifetime from both the healthcare system and societal perspectives, which included the cost of productivity loss due to HCV-related deaths. The incremental cost-effectiveness ratio (ICER) between universal screening and no screening was estimated. Results: The HCV screening strategy had an ICER of $2,666/QALY and $431/QALY from the healthcare system and societal perspectives, respectively. Both ICERs were far less than the willingness-to-pay threshold of $25,000/QALY, showing that universal screening was highly cost-effective compared to no screening. In various sensitivity analyses, the most influential parameters on cost-effectiveness were the antibodies to HCV (anti-HCV) prevalence, screening costs, and treatment acceptance; however, all ICERs were consistently less than the threshold. If the anti-HCV prevalence was over 0.18%, screening could be cost-effective. Conclusions One-time universal HCV screening in the Korean population aged 40–65 years using NHE program would be highly cost-effective from both healthcare system and societal perspectives.

PURPOSE:This study was designed to know the clinical significance and risk factors of hyperkalemia in very low birth weight infants (VLBWI). METHODS:We compared the incidence of hyperkalemia and its associated ECG abnormalities and mortality rate according to birth weight (102 of less than 1,000 g vs. 328 of 1,000 to 1,500 g) in 430 VLBWI who were born from Jan. 2000 to July 2004, retrospectively, and also compared the several parameter according to serum potassium (35 of hyperkalemia vs. 11 of normokalemia) in 49 selected VLBWI who need mechanical ventilation for respiratory distress without oliguria within 72 hours of life to know the risk factors of hyperkalemia. RESULTS:Overall incidence of hyperkalemia in VLBWI was 21.1%, and was significantly higher in below 1,000 g than in 1,000 to 1,500 g (32.4% vs. 17.7%, P<0.05). Hyperkalemia associated ECG abnormalities, life-threatening cardiac arrhythmia, and death were also significantly higher in below 1,000 g. There were no significant differences in maternal or infant's characteristics, laboratory findings and clinical conditions between hyperkalemic vs. normokalemic group. The incidence of cardiac arrhythmia and mortality rate were also significantly higher in hyperkalemic group. CONCLUSION:Early onset nonoliguric hyperkalemia is often associated with life- threatening cardiac arrhythmia and death in VLBWI, especially less than 1,000 g. Although perinatal risk factors were not found in this study, prospective study is needed to establish the preventive strategy and to improve the outcome.
Arrhythmias, Cardiac ; Birth Weight ; Electrocardiography ; Humans ; Hyperkalemia* ; Incidence ; Infant* ; Infant, Very Low Birth Weight* ; Mortality ; Oliguria ; Potassium ; Respiration, Artificial ; Retrospective Studies ; Risk Factors

Pharmacokinetic interaction of chrysin, a flavone present in honey, propolis and herbs, with caffeine was investigated in male Sprague-Dawley rats. Because chrysin inhibited CYP1A-selective ethoxyresorufin O-deethylase and methoxyresorufin O-demethylase activities in enriched rat liver microsomes, the pharmacokinetics of caffeine, a CYP 1A substrate, was studied following an intragastric administration with 100 mg/kg chrysin. In addition to the oral bioavailability of chrysin, its phase 2 metabolites, chrysin sulfate and chrysin glucuronide, were determined in rat plasma. As results, the pharmacokinetic parameters for caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) were not changed following chrysin treatment in vivo, despite of its inhibitory effect on CYP 1A in vitro. The bioavailability of chrysin was found to be almost zero, because chrysin was rapidly metabolized to its sulfate and glucuronide conjugates in rats. Taken together, it was concluded that the little interaction of chrysin with caffeine might be resulted from the rapid metabolism of chrysin to its phase 2 metabolites which would not have inhibitory effects on CYP enzymes responsible for caffeine metabolism.
Animals ; Biological Availability ; Caffeine* ; Cytochrome P-450 CYP1A1 ; Drug Interactions ; Honey ; Humans ; In Vitro Techniques ; Male ; Metabolism ; Microsomes, Liver ; Pharmacokinetics ; Plasma ; Propolis ; Rats* ; Rats, Sprague-Dawley ; Theobromine

PURPOSE: The purpose of this study was to evaluate the diagnostic accuracy of CT and MR virtual colonoscopy using an experimental model of colonic polyposis. MATERIALS AND METHODS: Eleven pig colons ranging from 15 to 20cm in length were cleansed and a total of 99 variable sized polyps ranging from 3 to 15mm in diameter were created. The polyps were divided into three groups according to size: <5mm(n=23), 5-9mm(n=44), and ?10mm(n=32) in diameter. Each specimen was scanned using spiral CT and MRI. Each CT and MR virtual colonoscopy was independently evaluated by two radiologists blinded to the location, size and numbers of polyps, but aware that polyps were present. Interobserver agreement regarding the detection rate of the polyps during the two types of virtual colonoscopy was measured and the diagnostic accuracy of CT and MR virtual colonoscopy was compared. Results: In both CT and MR virtual colonoscopy, the detection rates determined by the two radiologists coincided in all three groups(p<0.05). The detection rates of polyps less than 5mm, between 5 and 9mm, and 10mm or larger in diameter were 74%(17/23), 89%(39/44), and 100%(32/32), respectively, in CT colonoscopy, and 61%(14/23), 89%(39/44), and 100%(32/32), respectively in MR colonoscopy. In polyps 5mm or larger, the results of the two types of virtual colonscopy coincided but in those less than 5mm in diameter, the results of MR virtual colonoscopy were slightly inferior to those of CT colonoscopy. Conclusion: Both CT and MR virtual colonoscopy provide high detection rates of colonic polyps 5mm or larger in diameter and these techniques can therefore be used to diagnose colonic mass lesions.
Colon ; Colonic Polyps ; Colonography, Computed Tomographic* ; Colonoscopy ; Magnetic Resonance Imaging ; Models, Theoretical ; Polyps* ; Tomography, Spiral Computed

PURPOSE: The purpose of this study was to evaluate the diagnostic accuracy of CT and MR virtual colonoscopy using an experimental model of colonic polyposis. MATERIALS AND METHODS: Eleven pig colons ranging from 15 to 20cm in length were cleansed and a total of 99 variable sized polyps ranging from 3 to 15mm in diameter were created. The polyps were divided into three groups according to size: <5mm(n=23), 5-9mm(n=44), and ?10mm(n=32) in diameter. Each specimen was scanned using spiral CT and MRI. Each CT and MR virtual colonoscopy was independently evaluated by two radiologists blinded to the location, size and numbers of polyps, but aware that polyps were present. Interobserver agreement regarding the detection rate of the polyps during the two types of virtual colonoscopy was measured and the diagnostic accuracy of CT and MR virtual colonoscopy was compared. Results: In both CT and MR virtual colonoscopy, the detection rates determined by the two radiologists coincided in all three groups(p<0.05). The detection rates of polyps less than 5mm, between 5 and 9mm, and 10mm or larger in diameter were 74%(17/23), 89%(39/44), and 100%(32/32), respectively, in CT colonoscopy, and 61%(14/23), 89%(39/44), and 100%(32/32), respectively in MR colonoscopy. In polyps 5mm or larger, the results of the two types of virtual colonscopy coincided but in those less than 5mm in diameter, the results of MR virtual colonoscopy were slightly inferior to those of CT colonoscopy. Conclusion: Both CT and MR virtual colonoscopy provide high detection rates of colonic polyps 5mm or larger in diameter and these techniques can therefore be used to diagnose colonic mass lesions.
Colon ; Colonic Polyps ; Colonography, Computed Tomographic* ; Colonoscopy ; Magnetic Resonance Imaging ; Models, Theoretical ; Polyps* ; Tomography, Spiral Computed

PURPOSE: To determine the usefulness of perfusion weighted MR imaging in the assessment of relative cerebral blood volume(rCBV) in brain tumors. MATERIALS AND METHODS: Twenty-three patients with primary or metastatic brain tumors [nine gliomas (6 high grade and 3 low), six metastatic tumors, five meningiomas (4 benign and 1 atypical), two neurilemmomas and one hemangioblastoma] underwent perfusion-weighted and conventional MR imaging. A total of 240 perfusion MR images were obtained from four axial slices after rapid injection of contrast media using a gradient echo planar imaging pulse sequence, and this was followed by postprocessing of these images to give CBV maps. In order to calculate the rCBV of tumor to normal white matter, ROIs were defined on the CBV map of a tumor and its contralateral normal white matter. RESULTS: The rCBV ratio of tumors to contralateral normal side was as follows: high-grade glioma, 0.40-5.64(mean +/-SD = 2.91 0.95); low grade astrocytoma, 0.77 -1.66 (mean +/-SD = 1.15 +/-0.28); benign menin-gioma,2.06 -4.90 (mean +/-SD = 3.59 +/-0.84); atypical meningioma, 0.46 -1.18 (mean +/-SD = 0.72 +/-0.25); neurilemmoma, 1.45 -3.85 (mean +/-SD = 2.56 +/-0.92); and hemangioblastoma, 6.16 -8.35 (mean +/-SD = 7.02 +/-1.12). High grade gliomas were more hypervascular than low grade astrocytomas, and showed a variable range of relative cerebral blood volume. In metaststic cancer, CBV maps showed a relatively high and variable blood volume. Benign meningiomas exhibited high relative cerebral blood volume, while in the atypical meningioma with cystic degeneration, this volume was low. In neurilemmomas, a variable range of relative cerebral blood volume, was noted, while in the mural nodule of the hemangioblastoma, this volume was the highest. CONCLUSION: Perfusion-weighted MRI indicated the rCBV of various brain tumor lesions, and this suggests that the modality can provide a very useful means of assessing brain tumor vascularity.
Astrocytoma ; Blood Volume ; Brain Neoplasms* ; Brain* ; Contrast Media ; Echo-Planar Imaging ; Glioma ; Hemangioblastoma ; Humans ; Magnetic Resonance Imaging* ; Meningioma ; Neurilemmoma ; Perfusion*

BACKGROUND/AIMS: Recent studies have reported the potentials of endoscopic papillary large balloon dilatation (EPLBD) with minor endoscopic sphincterotomy (EST) for the complete removal of common bile duct (CBD) stone in the high risk groups. However, there have been no reports about the recurrence of the CBD stone after EPLBD with minor EST. The aim of this study was to evlauate the recurrence of CBD stone after EPLBD with minor EST. METHODS: A total of 1,036 patients who underwent endoscopic treatment due to CBD stones at Pusan University Hospital were enrolled. The patients were classified into two groups: those who underwent EPLBD with minor EST (group 1) and those who underwent EST treatment (group 2). We investigated clinical factors and recurrence rate between two groups. RESULTS: The recurrence of CBD stone occurred in total of 74 patients (7%), and the recurrence rates of CBD stone were 21/321 (6.5%) in Group 1 and 53/715 (7.4%) in Group 2. There were no difference in the presence of diverticulum and the number and size of recurrent CBD stone between the two groups. In case of diverticulum existence, recurrence rates were 12/158 (7.6%) in Group 1 and 21/101 (20.8%) in Group 2. When compared to the case of no diverticulum existence (Group 1: 9/163 [5.5%], Group 2: 32/614 [5.2%]), the recurrence rate of CBD stone was significantly lower if treated after EPLBD with minor EST (p<0.01). CONCLUSIONS: CBD stone that recurs after going through EPLBD with minor EST can be successfully removed with an endoscopic treatment. The recurrence of CBD stone was especially lower in cases with periampullary diverticulum and treated with EPLBD with minor EST. Our results will be helpful in endoscopic retreatment and preventing the recurrence of CBD stone.

PURPOSE: In patients with colorectal carcinoma, helical CT using air as a contrast agent provides axial images and a three-dimensional CT colonogram similar to that provided by barium enema. The purpose of this study was to assess the usefulness of air insufflation helical CT in colorectal cancer patients. MATERIALS AND METHODS: Thirty-three patients with colorectal carcinoma confirmed by surgery underwent air insufflation helical CT scanning after the infusion of air through the anus. In eleven who underwent barium studies, CT colonograms were also obtained. Two radiologists, who reached a consensus, analysed the detection rate, location and staging of the tumors; staging was based on the modified Dukes (Astler-Coller) classification. RESULTS: Using axial helical CT, the detection rate was 97%; staging was correct in 23 of the 33 patients, with an overall accuracy of 70%. Pathologic correlation was correct in 30 of the 33 cases (three were overestimated), and sensitivity, specificity and accuracy were 100%, 50%, and 91%, respectively. With regard to the involvement of lymph nodes, pathologic correlation was correct in 25 of the 33 patients; four were overestimated and four were underestimated. Sensitivity, specificity and accuracy were 69%, 80%, and 76%, respectively. The detection rate of CT colonography was 100%, but because in one case there was a discrepancy between CT colonography and barium enema as to the shape of the carcinoma, the agreement rate was 91%. CONCLUSION: Air insufflation helical CT, which provides a higher detection rate and more precise staging of colorectal carcinoma than the use of positive contrast materials and three dimensional depiction of tumor location, is helpful for the evaluation of colorectal carcinoma.
Anal Canal ; Barium ; Classification ; Colonography, Computed Tomographic ; Colorectal Neoplasms* ; Consensus ; Contrast Media ; Enema ; Humans ; Insufflation* ; Lymph Nodes ; Sensitivity and Specificity ; Tomography, Spiral Computed*

PURPOSE: To determine the usefulness of in-vivo proton MR spectroscopy (MRS) with short TE for grading glial brain tumors. MATERIALS AND METHODS: For the purpose of tumor grading, 32 patients with pathologically confirmed glial tu-mors were examined by proton MRS. This and MRI were performed on a 1.5 T superconductive MR scanner. T2-weighted FSE images (TR/TE=4,000/100msec) were used to obtain anatomical reference images. The stim-ulated- echo acquisition mode (STEAM: TR/TE/MT=3000/30/13.7msec) was used to acquire MRS data from the localized single-voxel (2 x2 x2 cm 3 ) in both hemispheres. Residual water resonance in the spectra was re-moved using a CHESS pulse sequence. Prior to baseline correction, MRS raw-data, free induction decay sig-nals were zero-filled, apodized by an exponential function with 8Hz line-broadening, and fourier transformed. To normalize signal intensities of metabolites such as N-acetyl aspartate (NAA), total choline (Cho), myo-inosi-tol (mI), and lactate (Lac), the creatine(Cr) peak was used as a standard. RESULTS: The concentration ratios of Cho/Cr, mI/Cr, alpha-Glx, Lac, and NAA/Cr changed linearly according to tu-mor grade. Increased Cho, mI, alpha-Glx, and Lac levels were clearly seen in all grades. The most dramatic in-creases, observed in either Grade III or IV, were 78% and 228% for Cho(p<0.001), 106% and 61% for mI (p<0.001), 32% and 5% for alpha-Glx, and 727% and 450% for Lac (p<0.001), respectively. Increase of concen-tration ratio of Lac/Cr observed only in Grade III and Grade IV. The concentration ratios of NAA/Cr decreased gradually as tumor grade increased(p<0.001). CONCLUSION: The metabolic changes seen on proton MR spectroscopy using short TE might be useful for grad-ing glial brain tumors.
Aspartic Acid ; Brain Neoplasms ; Brain* ; Choline ; Fourier Analysis ; Humans ; Lactic Acid ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy* ; Neoplasm Grading ; Protons* ; Spectrum Analysis ; Water