Gak-Won Yun

Chungnam National University, Seongnam, Gyeonggi, South Korea

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Publications (6)0 Total impact

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    ABSTRACT: Antiphospholipid antibodies (aPL) have been detected in various proportions of patients with primary immune thrombocytopenia (ITP), but the clinical significance of this is debatable. The present study aimed to determine the frequency and clinical implications of elevated aPL in adult patients with ITP. We prospectively studied newly diagnosed adult patients with ITP who were enrolled between January 2003 and December 2008 at Chungnam National University Hospital. They were evaluated for the presence of lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) at diagnosis and were followed for the development of thrombosis. Seventy consecutive patients with ITP (median age, 48 years; range, 18 to 79) were enrolled. Twenty patients (28.5%) were positive for aPL at the time of diagnosis: aCL alone in 15 (75%), aCL and LA in two (10%), and LA alone in three (15%). Patients who had platelet counts < 50,000/µL were administered oral prednisolone with or without intravenous immune globulin. No difference was found between the aPL-positive and -negative groups regarding gender, initial platelet count, and response to the therapy. After a median follow-up of 20 months (range, 2 to 68), two of 20 patients who were aPL-positive (10%) developed thrombosis, whereas no thrombotic event was found among those who were aPL-negative. Our data suggest that aPL levels should be determined at the initial presentation of ITP and that patients found to be aPL-positive should receive closer follow-up for thrombotic events.
    The Korean Journal of Internal Medicine 12/2011; 26(4):449-54. DOI:10.3904/kjim.2011.26.4.449
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    ABSTRACT: Hypocellularity of bone marrow (BM), not associated with significant dyshematopoiesis, is often found in patients with isolated thrombocytopenia, but its clinical implications have not been studied. We prospectively studied the clinical features and natural history of these patients. Adults with isolated thrombocytopenia (platelet counts <100×10(9)/L) in the absence of dyshematopoiesis, cytogenetic abnormalities, or megakaryocytic hyperplasia and who had BM hypocellularity (below 30% in patients aged less than 60 years; below 20% in patients aged 60 years or more) were enrolled at Chungnam National University Hospital between January 2002 and December 2006. They were monitored regularly for changes in platelet counts or development of additional cytopenia. Twenty patients (17 men and 3 women) were enrolled in the study. The median age was 29 years (range, 18-70 years). At initial presentation, the platelet counts ranged from 12×10(9)/L to 99×10(9)/L (median, 63×10(9)/L) and were >50×10(9)/L in 16 patients (80%). BM cellularity ranged from 5% to 25% (median, 15%) and was ≤10% in 6 patients (30%). During the median 48-month follow-up (range, 12-90 months), platelet counts of 3 of the 20 patients recovered to normal levels (>150×10(9)/L) after 12, 56 and 66 months. Three patients developed pancytopenia after 11, 70 and 90 months. Two patients were consistent with moderate aplastic anemia, and 1 was confirmed as having refractory cytopenia with multilineage dysplasia. In the remainder of the patients, platelet counts remained unchanged. Isolated thrombocytopenia accompanied by hypocellular marrow encompasses a group of heterogeneous conditions.
    The Korean journal of hematology 06/2011; 46(2):128-34. DOI:10.5045/kjh.2011.46.2.128
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    ABSTRACT: Central nervous system (CNS) myelomatosis, which is the presence of monoclonal plasma cells in the cerebrospinal fluid (CSF), is extremely rare. We report a case of CNS myelomatosis developed in a 45-year-old woman with multiple myeloma in complete response, which was achieved by allogeneic peripheral blood stem cell transplantation using a reduced-intensity conditioning regimen consisting of melphalan, fludarabine, and antithymocyte globulin. Two months after the transplant, she developed a moderate motor and sensory weakness in both lower extremities. Atypical plasma cells were found in the CSF, and immunofixation revealed monoclonal light chain in the CSF. She was given three courses of weekly intra-thecal chemotherapy consisting of methotrexate, cytarabine, and dexamethasone, which cleared the CSF. This case indicates that the allogeneic transplantation could not control CNS myelomatosis, despite successfully treating the bone marrow myeloma.
    The Korean journal of hematology 01/2008; 43(3). DOI:10.5045/kjh.2008.43.3.194
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    ABSTRACT: Bone marrow (BM) mesenchymal stem cells (MSCs) can be expanded over 20~30 cell doublings in vitro even in the absence of any growth factors. However, the mechanisms that govern MSC proliferation are not well understood.
    The Korean journal of hematology 01/2007; 42(1). DOI:10.5045/kjh.2007.42.1.24
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    ABSTRACT: Pernicious anemia is the most common cause of vitamin B12 deficiency in western populations, but to date, only case reports or small series dealing with this malady have been reported in Korea. This study describes the clinical characteristics of pernicious anemia in Koreans.
    The Korean journal of hematology 01/2005; 40(4). DOI:10.5045/kjh.2005.40.4.219
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    ABSTRACT: Warfarin is one of the most commonly used oral anticoagulant. It is well established that a wide range of drugs, including the anticancer drug 5-fluorouracil, interact with warfarin; this results in altered coagulation parameters and bleeding sequelae. To date, any drug interaction between warfarin and TS-1 has not been reported on. A 58-yr old woman visited emergency department with gross hematuria and soft tissue swelling involving her left thigh and buttock. She had been diagnosed as having advanced colon cancer (Duke's classification D); she had undergone right hemicolectomy and partial hepatectomy, and she had received 5-FU/leucovorin chemotherapy two years prior to admission. Recurrent disease was revealed in the liver and lungs, and so 6 cycles of FOLFIRI (5-FU, leucovorin and irinotecan) chemotherapy were given. Follow-up abdominal CT scan showed progressive disease and then TS-1 oral chemotherapy was started. She took warfarin 2mg per day because of partial thrombosis in the lower inferior vena cava and left ovarian vein. The initial laboratory tests revealed a prothrombin time of 120 seconds and an international normalized ratio of 35. Fresh frozen plasma and a parenteral vitamin K injection were given. After resorption of the subcutaneous hematoma, warfarin was restarted at a dose of 1mg per day. This case shows the significant increased bleeding tendency following the combined administration of warfarin and TS-1. Because of the potential severity of this interaction, close monitoring of the coagulation parameters is recommended for patients receiving warfarin together with TS-1.
    The Korean journal of hematology 01/2005; 40(4). DOI:10.5045/kjh.2005.40.4.271