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Biomedical subjects

C Y Chon

Publications and source records attributed to C Y Chon.

At least 19 recordsLinked to original sources
PubMed2001

Emergence of YMDD motif mutant of hepatitis B virus during short-term lamivudine therapy in South Korea.

BACKGROUND/AIMS: The emergence of a YMDD mutant resistant to lamivudine therapy has been reported in patients with hepatitis B treated with long-term lamivudine therapy. However, it is not well known whether the YMDD mutant could be detected early in lamivudine therapy in hepatitis B virus (HBV) endemic areas. The aim of this study was to investigate the emergence of the YMDD mutant during short-term lamivudine therapy in South Korea. METHODS: We prospectively investigated the emergence of the YMDD mutant by the nested PCR assay using restriction fragment length polymorphism in 28 patients with chronic hepatitis B who were treated with 100 mg of lamivudine daily for 12 weeks. RESULTS: The YMDD mutant was detected in 17 (60.7%) out of 28 patients at week 12, and the only type of mutation found was the YIDD mutation. When we carried out the nested PCR serially in five patients, YIDD mutants were detected as early as 2 weeks by the nested PCR assay. The nested PCR results were in concordance with DNA sequencing in one patient's serial samples. CONCLUSIONS: YMDD mutants in HBV were detected within a few weeks during lamivudine therapy in South Korea, which suggests that the YMDD mutant may exist even before lamivudine therapy in HBV endemic areas.

Adult↗
PubMed2001

Effects of nonsteroidal anti-inflammatory drugs on Helicobacter pylori-infected gastric mucosae of mice: apoptosis, cell proliferation, and inflammatory activity.

Helicobacter pylori and nonsteroidal anti-inflammatory drugs (NSAIDs) are two well-known important causative factors of gastric damage. While H. pylori increases apoptosis and the proliferation of gastric epithelial cells and is an important factor in peptic ulcer and gastric cancer, NSAIDs induce cell apoptosis and have antineoplastic effects. We investigated the effects of NSAIDs (a nonselective cyclooxygenase [COX] inhibitor [indomethacin] and a selective COX-2 inhibitor [NS-398]) on the apoptosis and proliferation of gastric epithelial cells and gastric inflammation in H. pylori-infected mice. C57BL/6 mice were sacrificed 8 weeks after H. pylori SS1 inoculation. Indomethacin (2 mg/kg) or NS-398 (10 mg/kg) was administered subcutaneously once daily for 10 days before sacrifice. The following were assessed: gastric inflammatory activity, gastric COX protein expression by Western blotting; gastric prostaglandin E(2) levels by enzyme immunoassay, apoptosis by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling, and cell proliferation by Ki67 immunostaining. Compared to the controls, H. pylori infection and/or NSAID treatment increased COX-1 and COX-2 protein expression. Gastric prostaglandin E(2) levels, apoptotic index, cell proliferation index, neutrophil activity, and the degree of chronic inflammation were all increased by H. pylori infection, and these effects were significantly decreased by indomethacin treatment. However, NS-398 treatment after H. pylori infection did not induce a significant reduction, although it did result in a tendency to decrease. These results show that NSAIDs can reverse the increased apoptosis and proliferation of epithelial cells and inflammatory activity in the stomachs of H. pylori-infected mice and that, like COX-2 activation, COX-1 induction contributes to the change of gastric mucosal cell turnover and inflammation induced by H. pylori infection.

Animals↗
PubMed2001

Oxidative stress effect on the activation of hepatic stellate cells.

Collagen is the most excessive extracellular matrix protein in hepatic fibrosis. Activated, but not quiescent, hepatic stellate cells (HSCs) have a high level of collagen and a smooth muscle actin (alpha SMA) expression. HSCs play a key role in the pathogenesis of hepatic fibrosis. We analyzed a mechanism leading to HSC activation by evaluating the role of oxidative stress and the expression of NFkB. In vitro study HSCs were proliferated (PCNA:2% vs 68%) and activated (alpha SMA: 5% vs 78%) by ascorbate/FeSO4, and HSCs activated by type I collagen were blocked (PCNA: 97% vs 4%, a SMA: 86% vs 9%) by a-tocopherol. In vivo study means of a SMA positive cells in liver at 400 x HPF were 48.3+/-5.2 and 15.2+/-1.8 and [3H]thymidine uptake of HSC was 529.2+/-284.8 cpm and 223.0+/-86.3 cpm in control and a-tocopherol treated group respectively at 32 hours after CCl4 injection. Nuclear extracts from activated, but not from quiescent, HSCs formed a complex with the NFkB cognate oligonucleotidesand alpha-tocopherol inhibited this bindings. This study indicates that oxidative stress plays an essential role through the induction of NFkB on HSC activation.

Actins↗
PubMed2001

An ischemic skin lesion after chemoembolization of the right internal mammary artery in a patient with hepatocellular carcinoma.

A huge nodular hepatocellular carcinoma located at the anterior superior portion of the left lobe in a patient with hepatocellular carcinoma was treated with transcatheter arterial chemoembolization through the left hepatic artery. Three months later, however, there was a re-elevation of the serum alpha-fetoprotein level and evidence of a marginal recurrence at the left side of the previously embolized tumor was noted on the postembolization computed tomographic scan. Although the hepatic artery was intact in the second hepatic arteriography, we found that the right internal mammary artery was feeding the recurred hepatocellular carcinoma. This internal mammary artery was successfully treated with Lipiodol-transcatheter arterial chemoembolization. However, an ischemic lesion occurred in the skin of the anterior chest and abdominal wall several days after internal mammary artery embolization. We report here a very rare case of ischemic skin lesion on the anterior chest and abdominal wall following transcatheter arterial chemoembolization of the right internal mammary artery. This internal mammary artery was embolized because it had developed a collateral tumor feeding vessel following the initial chemoembolization of a hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed2000

Local radiotherapy for unresectable hepatocellular carcinoma patients who failed with transcatheter arterial chemoembolization.

PURPOSE: The purpose of this study was to investigate the efficacy of local radiotherapy (RT) as a salvage treatment for unresectable hepatocellular carcinoma (HCC) patients who failed with transcatheter arterial chemoembolization (TACE). METHODS AND MATERIALS: Patients with unresectable HCC who had been treated with and eventually failed with TACE were eligible. The judgment of TACE failure was based on incomplete tumor filling of lipiodol-adriamycin mixture on either angiography or computed tomography (CT) scan. From January 1993 to December 1997, 27 patients were entered into this study. They had UICC Stage III (17) or IVA (10) disease, with a mean tumor size of 7.2 +/- 2.9 cm. Local RT was done, with a mean tumor dose of 51.8 +/- 7.9 Gy, in daily 1.8-Gy fractions using a 10- or 6-MV linear accelerator. Survival was calculated from both the diagnosis and the start of RT using the Kaplan-Meier method. RESULTS: An objective response was observed in 16 of 24 patients (66.7%) including 1 CR. Intrahepatic metastasis was noted outside the RT field in 10 patients (37.0%). Extrahepatic distant metastasis occurred in 4 patients. Survival rates at 1, 2, and 3 years were 85. 2%, 58.1%, and 33.2%, respectively, from the diagnosis and 55.9%, 35. 7%, and 21.4%, respectively, from the start of RT. The median survivals were 26 months from the diagnosis and 14 months from the start of RT. Acute toxicity involved alteration in liver function test (13 patients) and thrombocytopenia (2 patients). Subacute and chronic toxicity involved gastroduodenal ulcer (3 patients) and duodenitis (2 patients). There was no treatment-related death. CONCLUSION: In unresectable HCC patients who failed with TACE, local RT induced a substantial tumor response of 66.7%, with a 3-year survival rate of 21.4% and a median survival time of 14 months. Toxicity was significant but manageable. Although we do not know if there is survival benefit through this treatment, local RT in these patients seems to be valuable as a salvage for TACE-failed HCC.

Adult↗
PubMed2000

Association between hepatitis B virus infection and HLA-DR type in Korea.

Although the mechanism of susceptibility to chronic persistent hepatitis B virus (HBV) infection is not well clarified, immunogenetic factors of the host may have a role. Recently, a strong association between HLA-DR13 and the self-limited course of HBV infection has been reported. To determine whether the elimination of HBV is related to a particular HLA allele, we studied the HBV markers and HLA-DR phenotypes of 1,272 Koreans who had visited Yonsei University Medical Center for renal transplantation. They included 330 renal transplant donors. Subjects were categorized into 3 different groups: the "Unexposed Group" (UE; n = 946) with negative HBV markers, the "Chronic Carrier Group" (CC; n = 83), who were hepatitis B surface antigen (HBsAg)-positive, and the "Spontaneously Cleared Group" (SC; n = 243), who were HBsAg-negative with antibodies to HBsAg (anti-HBs) and hepatitis B core antigen (anti-HBc). HLA-DR4 was the most common type in all groups. HLA-DR6 was significantly more frequent in 69 of 243 subjects with SC (28. 4%) than in 8 of 83 subjects with CC (9.6%) (P <.001; relative risk [RR] = 3.72). HLA-DR9 was significantly more frequent in CC than in SC (P <.001; RR = 0.33). HLA-DR13 showed a stronger association with the clearance of HBV than the other HLA-DR6 subgroup. The distribution of HLA-DR phenotypes was similar regardless of renal disease. Our data indicate that HLA-DR6, especially HLA-DR13, is one of the host factors, which influences the immune response to HBV, and may be associated with self-elimination of HBV in Koreans.

Adult↗
PubMed1999

Combined transcatheter arterial chemoembolization and local radiotherapy of unresectable hepatocellular carcinoma.

PURPOSE: The best prognosis in hepatocellular carcinoma (HCC) can be achieved with surgical resection; however, the number of resected cases are limited due to advanced lesions or associated liver disease. The purpose of this study was to investigate the efficacy and toxicity of a prospective trial of combined transcatheter arterial chemoembolization (TACE) and local radiotherapy (RT) in unresectable HCC. METHODS AND MATERIALS: Patients with histologically proven unresectable HCC due to either advanced lesions or associated cirrhosis were eligible. From March 1992 to August 1994, 30 patients were entered into this study. TACE was performed with Lipiodol (5 ml) and doxorubicin (Adriamycin ; 50 mg), followed by gelatin sponge particle (Gelfoam) embolization. Local RT was started within 7-10 days following TACE. Mean tumor dose was 44.0+/-9.3 Gy in daily 1.8 Gy fractions. Response was assessed by computerized tomography (CT) scan 4-6 weeks following completion of the treatment and then at 1-3-month intervals. Survival was calculated from the start of TACE using the Kaplan-Meier method. RESULTS: An objective response was observed in 19 patients, giving a response rate of 63.3%. Distant metastasis occurred in 10 patients, with 8 in the lung only and 2 in both lung and bone. Survival rates at 1, 2, and 3 years were 67%, 33.3%, and 22.2%, respectively. Median survival was 17 months. There were 6 patients surviving more than 3 years. Toxicity included transient elevation of liver function tests in all patients, fever in 20, thrombocytopenia in 4, and nausea and vomiting in 1. There was no treatment-related death. CONCLUSION: Combined TACE and local RT is feasible and tolerable. It gives a 63.3% response rate with median survival of 17 months. We feel that this regimen would be a new promising modality in unresectable HCC. Further study is required to compare the therapeutic efficacy of this regimen to TACE alone.

Adult↗
PubMed1999

A novel primer-extension assay for the detection of a G to A mutation in the distal precore region of hepatitis B virus DNA.

The roles of genetic heterogeneity of the hepatitis B virus (HBV) precore gene in the pathogenesis of HBV infection are unclear. Various methods have been used to detect nucleotide (nt) 1896 precore mutants. We established a new primer-extension assay to facilitate the detection of these mutants. This assay is based upon the fact that there is no adenine in the distal precore region of wild-type HBV. Polymerase chain reaction (PCR)-amplified template DNA was denatured and annealed to the [gamma-32P]-labelled primer. During primer extension in the presence of DNA polymerase and dCTP, dGTP, dTTP and ddATP, the reaction terminates if there is a nucleotide A. When mixtures of different ratios of wild-type and nt 1896 precore mutants were analysed in the primer-extension assay, correlation between the percentage known amounts and the percentage measured amounts of nt 1896 precore mutants was excellent (r2=0. 9669). When the primer-extension assay and direct sequencing were compared in hepatitis B e antigen (HBeAg)-positive and -negative chronic active hepatitis B patients, the primer-extension assay detected a greater number of nt 1896 precore mutants than direct sequencing and thus most HBV infections were found to be mixed infections. In conclusion, the primer-extension assay is a reliable and sensitive method for the detection of nt 1896 precore mutants.

Adult↗
PubMed1998

Membranoproliferative glomerulonephritis associated with HCV infection in native kidneys and renal allograft.

Hepatitis C viral infection occurs relatively low in Korea compared to hepatitis B. However, it progresses into chronic hepatitis and cirrhosis more frequently than HBV. It may be associated with cryoglobulinemia and glomerulonephritis, both in native and transplanted kidneys. We report three cases of membrano-proliferative glomerulonephritis type I in anti-HCV positive, but cryoglobulin-negative patients, presenting massive proteinuria, two in native kidneys and one in an allograft. HCV-RNA was positive in sera of two patients. Two were cirrhotic and ALT was mildly elevated in two. In addition to the characteristic membranoproliferative feature, two native kidneys overlapped with features of diabetic nephropathy. Immunofluorescence demonstrated mainly IgM and C3 deposits along the peripheral capillary walls. Subendothelial electron dense deposits were present in the glomeruli of all three cases with subepithelial and intramembranous deposits in two. HCV-RNA was associated not only with a greater amount of immune deposits but also with subepithelial and intramembranous deposits, indicating the role of active infection.

Adult↗
PubMed1997

Nitinol self-expanding stents: when severe twisting occurs, self-expansion may ensue after a waiting period.

One of the major disadvantages of nitinol endocoil stents is said to be incomplete deployment leading to twisting and stent dysfunction. We report a patient with irresectable pancreatic head cancer where severe twisting of the nitinol stent occurred which resolved on the day after stent insertion; the stent took its normal shape ten days later, whereafter the patient lived without stent-related problems for one year until his death. This shows that prospective management rather than immediate stent extraction may be warranted in such cases of stent dysfunction.

Aged↗
PubMed1996

Anorectal dysfunction in systemic sclerosis.

This study was aimed to evaluate the anorectal dysfunction in systemic sclerosis (SSc) and propose the clinical significance of anorectal manometry in patients with SSc. Seven patients with SSc were evaluated with manometry for anorectal function and an additional 11 normal subjects were collected as a control group. The study group underwent esophageal manometry as well and the correlation between the degree of anorectal and esophageal dysfunction was evaluated. Patients showed a lower tolerance for balloon distention of the rectum than controls (minimal sensory volume and urgency volume, P < 0.05). The resting and squeezing pressure of the anal sphincter and the functional length of the anal canal showed no significant difference in these two groups. Rectoanal inhibitory reflex was absent in one (14%) and diminished in two (29%) of seven patients with SSc. SSc patients also showed abnormal esophageal manometry findings, notably decreased LES pressure and body amplitude of distal 2/3 esophagus. The comparison between manometric profiles of anorectum and esophagus showed no significant correlation by statistical analysis. In conclusion, our data could suggest that anorectal function may be impaired in patients with SSc which could reflect the involvement of the anorectum by the disease, and that anorectal manometric studies can be useful to detect such dysfunction in patients with SSc, even before clinical symptoms.

Adult↗
PubMed1996

Sebaceous glands in the esophagus.

We report a case of sebaceous glands in the esophagus diagnosed by endoscopic biopsy. The patient was a 47-year-old Korean man presented with postprandial pain of several months duration. An endoscopic examination disclosed an early gastric carcinoma in the gastric antrum and a 0.4 x 0.4 cm sized irregular lobulated nodule in the middle esophagus. Microscopically, the lobule was proven to be sebaceous glands in the submucosa. Possible histogenesis of this lesion is discussed.

Choristoma↗
PubMed1996

A case of paraesophageal hernia repaired by laparoscopic approach.

Paraesophageal hernia comprises only 2 approximately 5% of all hiatal hernias but is prone to incarceration and strangulation. For this reason they must be recognized and repaired as expeditiously as possible. The laparoscopic approach has already been successfully applied to the repair of the more common sliding hiatal hernia and it seems reasonable to propose that the paraesophageal hernia, provided it is not complicated, might also be repaired by the laparoscopic technique. We present here a case of paraesophageal hernia which has been successfully repaired by the laparoscopic approach. A 73-year-old female suffering from postprandial fullness in the retrosternal area was diagnosed preoperatively with paraesophageal hiatal hernia with gastroesophageal acid reflux and was submitted for laparoscopic repair. The procedure entailed reduction of the hernia, mobilization of the esophagogastric junction with crural repair and partial fundoplication. At the 9th-month follow-up, the patient had remained asymptomatic and follow-up studies revealed no evidence of hernia or acid reflux. As a result of this favorable experience with minimal morbidity, early hospital discharge, and effective control of symptoms without adverse sequalae, laparoscopic repair can be considered as the curative and minimal invasive method in the management of paraesophageal hernia.

Aged↗
PubMed1996

Spontaneous bowel perforation during the course of acute pancreatitis--a case report.

We recently experienced a case of spontaneous perforation of infected necrosis into the colon and duodenum during the course of acute pancreatitis in a 63 year-old male patient. Enteric perforations or fistulas in the setting of acute pancreatitis implicate severe underlying pathology and have substantial morbidity and mortality. In the meantime it has generally been accepted that infected pancreatic or peripancreatic necrosis should be managed surgically as soon as possible. Enteric perforations in the present case contributed to transient improvement of the patient's infection sign and condition, and thus an early operation was able to be avoided. Delayed surgical management resulted in complete recovery of the patient without postoperative morbidity. Herein we report an unusual complication of acute pancreatitis.

Acute Disease↗
PubMed1996

A case of flutamide-induced acute cholestatic hepatitis--a case report.

Flutamide, an oral nonsteroidal, antiandrogenic, anilid compound which inhibits the uptake and binding of androgens to nuclear receptors in the prostate, is used with or without LH-RH analogues for treatment of patients with metastatic carcinoma of the prostate. Clinically significant hepatotoxicities such as toxic hepatitis, cholestatic hepatitis, hepatic failure, and even death have rarely been reported in the English literature, but no case has been reported in Korea. A 75-year-old man with metastatic carcinoma of the prostate had taken flutamide (750 mg/day) for 7 months and suddenly developed jaundice and general weakness. The findings of blood chemistries were compatible with cholestatic hepatitis, but ultrasonography, viral marker and auto-antibody studies did not reveal any attributable causes. Histologic examination of a sono-guided liver biopsy only disclosed centrilobular cholestasis, nuclear glycogenosis and mild sinusoidal lymphocytic infiltration. Discontinuation of flutamide resulted in an almost full recovery of the patient's liver function in 2 months. We, herein, report a case of flutamide-induced acute choestatic hepatitis with a brief review of the literature.

Acute Disease↗
PubMed1996

Peritoneoscopic liver biopsy findings in asymptomatic chronic HBsAg carriers with normal liver function tests and no hepatomegaly.

Asymptomatic chronic HBsAg carriers with normal liver function tests are, in general regarded as having no liver pathology. Most of the histologic findings in asymptomatic chronic carriers have been reported from areas with low incidence of Hepatitis B virus (HBV) infection, such as North America and Western Europe. It is well known that there are many differences in HBV infection between low and high endemic areas, but there have been few reports on the histologic findings of asymptomatic chronic HBsAg carriers from endemic areas. The present study was undertaken in Korea which is one of the endemic areas for HBV infection and was designed to assess the prevalence of chronic liver disease by peritoneoscopic liver biopsy among asymptomatic chronic HBsAg carriers and to make a basis for the follow-up of asymptomatic chronic HBsAg carriers according to the results obtained. One hundred and ten asymptomatic HBsAg-positive carriers with normal liver function tests and no hepatomegaly were included in the study. Final diagnosis by peritoneoscopic liver biopsy revealed that of the 110 asymptomatic carriers only 27 (24.5%) had a histologically normal liver, while 51 (46.4%) had chronic liver diseases, and the remaining 32 (29.1%) had nonspecific histologic abnormalities (nonspecific reactive changes in 18 cases, cholestasis in 6 cases, and fatty change in 8 cases). Of the 51 patients with chronic liver diseases, 3 had liver cirrhosis, 4 chronic active hepatitis with cirrhosis, 11 chronic active hepatitis and 33 chronic persistent hepatitis. The frequency of liver cirrhosis and chronic active hepatitis with cirrhosis was significantly high in the over 30 years of age group (12.1%) than in the under 30 years of age group (0%; p = 0.011 by Fisher's exact test). In conclusion, 46.4% of the Korean asymptomatic chronic HBsAg carriers with normal liver function tests and no hepatomegaly had chronic liver disease. This finding contrasted with reports from low incidence areas of HBV infection. Our results suggest that in endemic areas, a liver biopsy should be considered to assess the status of liver disease in asymptomatic chronic HBsAg carriers even if liver function tests are normal and hepatomegaly is absent, and the result can be used as a basis for the follow-up of each asymptomatic chronic HBsAg carriers.

Adolescent↗
PubMed1996

Extrahepatic bile duct hepatocellular carcinoma without primary hepatic parenchymal lesions--a case report.

Obstructive jaundice is rarely a presenting symptom of hepatocellular carcinoma (HCC). Most of the cases in the literature describing obstructive jaundice by HCC have a major hepatic component. Extrahepatic HCCs without primary hepatic parenchymal lesions are extremely rare. We encountered a case of extrahepatic HCC without primary hepatic parenchymal lesions in a 36-year-old man who presented with jaundice. We extensively sought primary hepatic parenchymal lesions preparatively and postoperatively with hepatic angiography and combined computed tomography (CT) studies, such as CT arterioportography and lipiodol-CT. The patient has been followed up for 1 year without definite evidence of recurrence. We herein report an unusual manifestation of HCC.

Adult↗