Yoon Kyung Sohn

Catholic University of Daegu, Hayang, North Gyeongsang, South Korea

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Publications (8)16.96 Total impact

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    ABSTRACT: Brush cytology during ERCP can provide a pathologic diagnosis in malignant biliary obstruction. K-ras and p53 mutations are commonly found in biliary and pancreatic cancers. We evaluated the diagnostic yield of brush cytology and the changes obtained by adding p53 and K-ras staining. One hundred and forty patients with biliary obstruction who underwent ERCP with brush cytology during a 7-year period were included. The sensitivity and specificity of brush cytology only and with the addition of p53 and K-ras staining were obtained. Malignant biliary obstruction was confirmed in 119 patients. The sensitivity and specificity of brush cytology were 78.2% and 90.5%, respectively. The sensitivity of cytology was 77.3% at the ampulla-distal common bile duct (CBD), 92.6% at the mid common hepatic duct (CHD), and 94.7% at the proximal CBD-CHD (p<0.05); these values did not differ with the degree or the length of the obstruction. In the 97 patients who received additional p53 and K-ras staining, the sensitivity of cytology plus p53 was 88.2%, cytology plus K-ras was 84.0%, and cytology plus p53 and K-ras was 88.2%. The sensitivity of cytology plus p53 was higher than that of brush cytology only (95% confidence interval: 83.69-92.78 vs 72.65-83.65) but not that of cytology plus K-ras. Brush cytology for malignant biliary obstruction has a high diagnostic accuracy. Adding p53 staining can further improve the diagnostic yield, whereas K-ras staining does not.
    Gut and liver 06/2010; 4(2):219-25. · 1.31 Impact Factor
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    ABSTRACT: The aim of this study was to define the clinical, biochemical, and pathological characteristics of myopathy developed during clevudine therapy. We prospectively enrolled 36 consecutive myopathy patients who were receiving clevudine therapy for the treatment of chronic hepatitis B (CHB). We evaluated patients with a complete medical history, neurologic examination with a questionnaire on neuromuscular diseases, laboratory tests, electrophysiology studies, and muscle biopsies. The median duration of clevudine therapy was 18.0 months (ranging from 9 to 24 months). The chief complaint was weakness of the lower extremities in 30 patients (83.3%) and asthenia in five patients (13.9%). One patient (2.8%) had only persistently elevated serum muscle enzyme without any symptoms. Weakness of the lower extremity mainly involved proximal muscle group of the lower extremity, characterized by difficulty in climbing stairs (83.3%), a decrease in exercise capacity (75.0%) and difficulty in walking (55.6%). All patients showed an elevation of more than two of serum creatine kinase, lactate dehydrogenase, and lactate levels. Muscle biopsies performed in 23 patients revealed myopathic features with abnormal mitochondria in 21 patients, and nonspecific myositis in two patients. Motor weakness gradually improved after discontinuation of clevudine. Myopathy associated with clevudine is characterized by a weakness in proximal muscles of the lower extremities with elevated muscle enzymes and presumably caused by mitochondrial toxicities. Careful medical and serologic examinations are essential for the early detection and management of this potential adverse reaction in CHB patients under clevudine therapy.
    Journal of Hepatology 04/2010; 53(2):261-6. · 9.86 Impact Factor
  • Korean Journal of Pathology - KOREAN J PATHOL. 01/2010; 44(1).
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    ABSTRACT: Polymorphisms of genes from glutathione S-transferases (GSTs) and N-acetyltransferase 2 (NAT2) have been associated with increased susceptibility to various cancers. Previous results showed that East Asians such as Koreans, Japanese and Chinese have a much higher frequency of the GSTM1 and GSTT1 null genotypes and NAT2 rapid acetylator type. Therefore, we investigated the association between the polymorphic types of GSTs (GSTM1, GSTT1, GSTP1) and NAT2 and the incidence of gastric cancer which is one of the most prevalent cancers among the East Asians. It was performed in a case-control study consisting of 238 healthy subjects and 108 cancer patients (54 distal and 54 proximal carcinomas). We also evaluated the association between GSTs and NAT2 and the risk factors for gastric cancer such as alcohol consumption, smoking, H. pylori infection, family history of gastric cancer, and tumor location. In our study, the percentage of cases whose hometown was rural was higher than those of controls (odds ratio (OR) = 2.88; 95% CI = 1.72-4.76), and the frequency of the lower socio-economic status increased significantly in patients (OR = 2.53; 95% Cl = 1.59-4.02). There was no significant difference in the GST polymorphic types between the cases and controls. However, NAT2 rapid or intermediate acetylator types were frequently detected in the cases with family history of gastric cancer (OR = 1.92; 95% CI = 1.79-26.0). These results suggest that the hometown and socio-economic status are important environmental factors for gastric carcinogenesis, and NAT2 polymorphic types could be associated with familial gastric carcinoma.
    Journal of Preventive Medicine and Public Health 04/2006; 39(2):135-40.
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    ABSTRACT: Acute spinal cord injury (SCI) is two-step process that first involves the primary mechanical injury and then the secondary injury is induced by various biochemical reactions. Apoptosis is one of secondary SCI mechanisms and it is thought to play an important role for the delayed neuronal injury. The enhanced formation of nitric oxide (NO) via inducible nitric oxide synthase (iNOS) has been implicated in the pathogenesis of apoptosis in SCI. The level of .iNOS mRNA peaked at 6 hr after SCI and it declined until 72 hr after SCI in a rat model. Double-immunofluorescence staining revealed that iNOS positive cells were stained for ED-1, synaptophysin, GFAP, and oligodendrocyte marker. The terminal deoxynucleotidyl-transferase-mediated dUDP-biotin nick end-labeling (TUNEL) positive cell count was higher for the 72 hr post-SCI group than for the 24 hr post-SCI group. This cell count was also higher going in the caudal direction than in the rostral direction from the epicenter, and especially for the 72 hr group. Treatment with a selective iNOS inhibitor resulted in the reduction of TUNEL-positive cells at the lesion site. These findings suggest that nitric oxide generated by the iNOS of macrophages, neurons, oligodentrocytes, and astrocytes plays an important role for the acute secondary SCI that results from apoptotic cell death.
    Journal of Korean Medical Science 09/2005; 20(4):663-9. · 1.25 Impact Factor
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    ABSTRACT: The hypermethylation of the CpG islands is a common mechanism for the inactivation of tumor-related genes. In the present study, we analyzed the methylation status of genes for cell repair such as hMLH1, MGMT, and GSTP1, and a gastric cancer-specifically methylated DNA fragment, MINT 25 in gastric cancer cases and control groups. The study population consisted of 100 gastric cancer patients (50 distal and 50 proximal carcinomas), and 238 healthy controls. All genes showed more frequent hypermethylation in the cases than in the control group (p<0.0001). We investigated the association between promoter hypermethylation and relevant parameters including age, gender, alcohol consumption, smoking, and family history. There was a common hypermethylation of hMLH1 (p=0.008), MGMT (p= 0.0001), and GSTP1 (p=0.0003) in females. This study also demonstrates that hypermethylation was strongly associated with non-drinkers (MGMT, p=0.046 and MINT 25, p=0.049) and non-smokers (hMLH1, p=0.044; MGMT, p=0.0003; MINT 25, p=0.029). Moreover, the frequency of MINT 25 hypermethylation increased with age (p=0.037), and MGMT methylation was frequently detected in distal gastric cancer than in proximal type (p=0.038). Our study suggested that promoter hypermethylation of the genes involved in cell repair system and MINT 25 is associated strongly with some subgroups of primary gastric carcinoma.
    Journal of Korean Medical Science 04/2005; 20(2):236-41. · 1.25 Impact Factor
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    ABSTRACT: Background : Neuronal death in acute-phase cerebral ischemic injury is caused by necro-sis. However, neuronal injury after reperfusion can be associated with apoptosis. Methods : We used Sprague-Dawley rats whose brains were reperfused after middle cerebral artery occlusion for either 30 min or 2 h. We examined a relationship between apoptosis and the expression of inducible nitric oxide synthase (iNOS) in the brain tissue from 3 h to 14 days after reperfusion in both groups. Results : TUNEL and iNOS positivity were closely related in both groups. The 2-h ischemia group exhibited increases in the amount of TUNEL and iNOS-positive cells for up to 3 days after reperfusion, at which the TUNEL and iNOS-positive cells decreased. The 30-min ischemia group exhibited peak positivity 24 h after reperfusion, fol-lowed by a similar decrease. iNOS mRNA expression peaked 3 h after reperfusion in the 30-min ischemia group, at which time it decreased. In the 2-h ischemia group, iNOS mRNA increased 3 h after reperfusion, peaked 24 h after reperfusion, and then decreased. Conclu-sions : These results indicated the occurrence of delayed apoptosis in transient cerebral ischemia. Increased expression of iNOS is closely associated with this apoptosis, and oxy-gen free radical-producing materials, such as nitric oxide, may play an important role in the induction of this apoptosis.
    The Korean Journal of Pathology 01/2004; 38:364-71. · 0.17 Impact Factor
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    ABSTRACT: The Neuropathology Study Group of the Korean Society of Pathologists conducted a nationwide collection of central nervous system (CNS) tumors to evaluate the relative frequency in Korea of CNS tumors belonging to the revised World Health Organization (WHO) classification categories. A total of 3221 histologically proven cases of CNS tumors were collected from 13 institutes between 1997 and 1998. All the cases were classified according to the revised WHO histological types and analyzed for the relative frequency, the distribution of age and sex, and location of tumors. The most frequent type of CNS tumors in Korea was meningiomas, followed by pituitary adenoma, glioblastoma, astrocytoma, and schwannoma. Among the pediatric CNS tumors, pilocytic astrocytoma, medulloblastoma, craniopharyngioma, germ cell tumors, and ependymomas were common types of tumors. Compared with a previous nationwide study, the rates for neuronal/glial tumors, glioblastoma, malignant lymphoma, and cystic lesion were increased, and the rate of embryonal tumors was decreased. The overall male to female ratio was 0.9: 1, which may be attributed to the greater number of female-predominate meningiomas and pituitary adenoma. Compared with Western countries, Koreans had higher rates of pituitary adenoma and meningiomas and lower rate of gliomas. The relative frequency of CNS tumors among Koreans is very similar to that reported in Taiwan. The occurrence rates for various subtypes of CNS tumors in Korea are distinct from those in the United States and Europe and similar in many ways to those in Asian and Mexican population.
    Journal of Neuro-Oncology 03/2002; 56(3):251-9. · 3.12 Impact Factor

Publication Stats

77 Citations
16.96 Total Impact Points

Institutions

  • 2010
    • Catholic University of Daegu
      • Department of Internal Medicine
      Hayang, North Gyeongsang, South Korea
  • 2002–2010
    • Kyungpook National University
      • • Department of Internal Medicine
      • • Department of Oral Pathology
      • • Department of Pathology
      Daikyū, Daegu, South Korea
  • 2004
    • Sungkyunkwan University
      Sŏul, Seoul, South Korea