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Biomedical subjects

Byung Soo Kim

Publications and source records attributed to Byung Soo Kim.

At least 19 recordsLinked to original sources
PubMed2006

Tissue engineering of heart valves by recellularization of glutaraldehyde-fixed porcine valves using bone marrow-derived cells.

To increase the biocompatibility and durability of glutaraldehyde (GA)-fixed valves, a biological coating with viable endothelial cells (ECs) has been proposed. However, stable EC layers have not been formed successfully on GA-fixed valves due to their inability to repopulate. In this study, to improve cellular adhesion and proliferation, the GA-fixed prostheses were detoxified by treatment with citric acid to remove free aldehyde groups. Canine bone marrow mononuclear cells (MNCs) were differentiated into EC-like cells and myofibroblast-like cells in vitro. Detoxified prostheses were seeded and recellularized with differentiated bone marrow- derived cells (BMCs) for seven days. Untreated GA-fixed prostheses were used as controls. Cell attachment, proliferation, metabolic activity, and viability were investigated and cell-seeded leaflets were histologically analyzed. On detoxified GA-fixed prostheses, BMC seeding resulted in uninhibited cell proliferation after seven days. In contrast, on untreated GA-fixed prostheses, cell attachment was poor and no viable cells were observed. Positive staining for smooth muscle a-actin, CD31, and proliferating cell nuclear antigen was observed on the luminal side of the detoxified valve leaflets, indicating differentiation and proliferation of the seeded BMCs. These results demonstrate that the treatment of GA-fixed valves with citric acid established a surface more suitable for cellular attachment and proliferation. Engineering heart valves by seeding detoxified GA-fixed biological valve prostheses with BMCs may increase biocompatibility and durability of the prostheses. This method could be utilized as a new approach for the restoration of heart valve structure and function in the treatment of end-stage heart valve disease.

Actins↗
PubMed2006

Phase II study of a gemcitabine and cisplatin combination regimen in taxane resistant metastatic breast cancer.

PURPOSE: To determine the safety and efficacy of gemcitabine and cisplatin in patients with taxane resistant metastatic breast cancer. PATIENTS AND METHODS: Thirty-three taxane resistant metastatic breast cancer patients were treated with gemcitabine 1,250 mg/m2 IV infusion over 30 min on days 1 and 8, and with cisplatin 75 mg/m2 by IV infusion over 1 h on day 1 in 21 day cycles. RESULTS: Of the 30 evaluable patients, there were 9 (30%) partial responses and no complete response, an overall objective response rate of 30%. Median time to progression and median survival duration for all study subjects were 7 (95% CI 5.1-8.9 months) and 15 months (95% CI 10.5-19.5 months), respectively. Toxicities included grade 3 and 4 leucopenia in 10 (30%), thrombocytopenia in 6 (18%), anemia in 2 (6%) and oral mucositis in 2 (6%). No grade 3 or 4 peripheral neuropathy, renal dysfunction, hepatic dysfunction, or nausea/vomiting was observed, and no treatment-related deaths occurred. CONCLUSION: The described gemcitabine plus cisplatin combination was found to be an active and tolerable salvage regimen in patients with taxane resistant metastatic breast cancer.

Adult↗
PubMed2006

uPAR expression under hypoxic conditions depends on iNOS modulated ERK phosphorylation in the MDA-MB-231 breast carcinoma cell line.

Urokinase plasminogen activator receptor (uPAR) plays a major role in cancer invasion and metastasis and uPAR expression is correlated with a poor prognosis in various cancer types. Moreover, the expression of uPAR is increased under hypoxic conditions. Nitric oxide (NO) and its metabolites produced by inducible nitric oxide synthase (iNOS) are important products of hypoxic stress, and NO may activate or modulate extracellular signal regulated kinase (ERK). Here, we evaluated uPA, uPAR, and activated ERK levels under hypoxic conditions, and the modulatory effects of iNOS and NO in the MDA-MB-231 human breast cancer cell line. Cells were incubated in a hypoxic or normoxic incubator and treated with PD98059 (a MEK 1/2 inhibitor, which abrogates ERK phosphorylation) and aminoguanidine (a selective iNOS inhibitor). uPAR expression, ERK phosphorylation, and uPA activity were found to be increased under hypoxic conditions. Moreover, when cells were treated with PD98059 under hypoxic conditions, uPAR was downregulated, whereas aminoguanidine markedly increased ERK phosphorylation in a dose dependent manner. Furthermore, aminoguanidine increased uPAR expression and prevented the inhibition of uPAR expression by PD98059. These results demonstrated that uPAR is induced by hypoxia and that increased uPAR expression is mediated by ERK phosphorylation, which in turn is modulated by iNOS/NO in MDA-MB-231 cells. We conclude that iNOS/NO downregulates the expression of uPAR under hypoxic conditions via ERK pathway modulation.

Breast Neoplasms↗
PubMed2006

Treatment outcome of front-line systemic chemotherapy for localized extranodal NK/T cell lymphoma in nasal and upper aerodigestive tract.

We analysed the treatment outcome of localized extranodal NK/T cell lymphoma initially treated with CEOP-B chemotherapy based on the primary site of involvement (nasal cavity vs. upper aerodigestive tract) and treatment modality (chemotherapy vs. chemotherapy followed by radiotherapy. Forty-three patients newly diagnosed as extranodal NK/T cell lymphoma were analysed: 29 cases from nasal cavity/nasopharynx and 14 from upper aerodigestive tract. Twenty-six patients were treated with chemotherapy alone, while adjuvant radiotherapy was given to 17 patients. Overall response rate to front-line CEOP-B chemotherapy was 67.4% (29/43) and the complete remission (CR) rate was 44.2% (19/43). Median overall and disease-free survival was 26.87 months [95% confidence interval (CI) = 8.71 - 45.03] and 15.27 months (95% CI = 2.92 - 27.62). The responders (CR or partial response) to initial CEOP-B chemotherapy showed longer overall survival than non-responders (P = 0.0026). Local relapse was observed to be higher in the chemotherapy alone group compared to the chemoradiotherapy group. Adjuvant radiotherapy failed to improve survival; thus, the median disease-free survival of the chemotherapy and chemoradiotherapy groups was not different (P = 0.9101). There may be a tendency for better overall survival in group of upper aerodigestive tract lymphoma than the nasal cavity/nasopharynx group (P = 0.0643). However, front-line CEOP-B chemotherapy has a limited role and adjuvant radiotherapy failed to improve survival in localized extranodal NK/T cell lymphoma.

Adult↗
PubMed2006

Prospective analysis of treatment outcome and prognostic factors in patients with T-cell lymphomas treated by CEOP-B: single institutional study.

The important prognostic factors were evaluated for T-cell non-Hodgkin lymphoma (NHL) patients in a prospective study using the CEOP-B protocol [a modified cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP)-like regimen that uses epirubicin instead of doxorubicin with the addition of bleomycin]. Fifty-two patients were enrolled in the study. The overall response rate was 63.5%. The median progression-free survival (PFS) and median overall survival (OS) was 18.0 and 39.5 months respectively. The most common toxicity was neutropenia. The factors related to poor outcome were a high International Prognostic Index (IPI) and a high 'B' score (bone marrow involvement, B symptoms, bulky disease). We developed a new prognostic model, namely the Prognostic Group for T cell NHL (PGT) that included four groups: PGT1 (low IPI/low B score), PGT2 (low IPI/high B score), PGT3 (high IPI/Low B score) and PGT4 (high IPI/Low B score). OS and PFS (not reached, 48 months) in the PGT1 group were significantly longer than those (11.5 and 4.8 months) in PGT2. The same result was observed in the PGT3 and PGT4 groups. The CEOP-B regimen was moderately active and tolerable for T-cell NHL patients, and the PGT system might be useful for the prediction of long-term survival of T-cell NHL patients.

Adolescent↗
PubMed2006

The impact of intima-media thickness of radial artery on early failure of radiocephalic arteriovenous fistula in hemodialysis patients.

This study was performed to investigate the impact of intima-media thickness (IMT) of radial artery on early failure of radiocephalic arteriovenous fistula (AVF) in hemodialysis (HD) patients. Ninety uremic patients undergoing radiocephalic AVF operation were included in this study. During the operation, 10-mm long partial arterial walls were removed with elliptical form for microscopic analysis. Specimens were stained with trichrome and examined by a pathologist blinded to the clinical data. And then AVF patency was followed up for 1 yr after the operation. Of the total 90 patients, 31 patients (34%) had AVF failure within 1 yr after the operation. Mean IMT was thicker in failed group (n=31) than in patent group (n=59) (486+/-130 micrometer vs. 398+/-130 micrometer, p=0.004). The AVF patency rate within 1 yr after the operation was lower in patients with IMT > or = 500 micrometer (n=26) than in patients with IMT <500 micrometer (n=64) (p=0.017). Age was an independent risk factor of IMT. Diabetes mellitus tended to be independent risk factor but not statistically significant. Our data suggest that increased radial artery IMT is closely associated with early failure of radiocephalic AVF in HD patients.

Adult↗
PubMed2005

Identification and functional characterization of an alternative splice variant within the fourth exon of human nanog.

Nanog, a homeodomain (HD) transcription factor, plays a critical role in the maintenance of embryonic stem (ES) cell self-renewal. Here, we report the identification of an alternatively-spliced variant of nanog. This variant lacked a stretch of amino acids (residues 168-183) located between the HD and tryptophan-repeat (WR) of the previously-reported full length sequence, suggesting that the deleted sequence functions as a linker and possibly affects the flexibility of the C-terminal transactivation domain relative to the DNA binding domain. Expression of mRNA encoding the splice variant, designated as nanog-delta 48, was much lower than that of the full length version in human ES cells. The ratio of nanog-delta 48 transcript to full length transcript increased, however, in multipotent adult progenitor cells. EMSA analysis revealed that both forms of Nanog were able to bind a nanog binding sequence with roughly the same affinity. A reporter plasmid assay also showed that both variants of nanog modestly repressed transactivation of gata-4, whose expression is proposed to be inhibited by nanog, with comparable potency. We conclude that, despite the difference in primary structure and expression pattern in various stem cells, the alternatively-spliced variant of Nanog has similar activity to that of the full length version.

Alternative Splicing↗
PubMed2005

Increased expression of ICAM-3 is associated with radiation resistance in cervical cancer.

To search for a marker that predicts the efficacy of radiation therapy in human cervical cancer, gene expression profiles between parental SiHa cervical cancer cells and radiation-resistant SiHa/R cells have been compared by the microarray technique. Microarray and Northern blot analyses demonstrated that the ICAM-3 expression was upregulated in SiHa/R cells. This increased expression of ICAM-3 in SiHa cells enhanced cell survival by about 34.3% after a 2 Gy dosage of radiation. In addition, SiHa/ICAM-3 cells showed a 2.45-fold higher level of FAK phosphorylation than that of the control cells. In tumor specimens, ICAM-3 staining was restricted to tumor stromal endothelial cells and lymphocytes. The overexpression of ICAM-3 was significantly more frequent in radiation-resistant cervical cancer specimens when compared with radiation-sensitive specimens (83.3% vs. 35.3%; p = 0.015). With these observations, we can suggest that an increased expression of ICAM-3 is associated with radiation resistance in cervical cancer cells and the expression of ICAM-3 can be used as a valuable biomarker to predict the radiation resistance in cervical cancer that occurs during radiotherapy.

Antigens, CD↗
PubMed2005

Hematopoietic differentiation of embryoid bodies derived from the human embryonic stem cell line SNUhES3 in co-culture with human bone marrow stromal cells.

Human embryonic stem (ES) cells can be induced to differentiate into hematopoietic precursor cells via two methods: the formation of embryoid bodies (EBs) and co-culture with mouse bone marrow (BM) stromal cells. In this study, the above two methods have been combined by co-culture of human ES-cell-derived EBs with human BM stromal cells. The efficacy of this method was compared with that using EB formation alone. The undifferentiated human ES cell line SNUhES3 was allowed to form EBs for two days, then EBs were induced to differentiate in the presence of a different serum concentration (EB and EB/high FBS group), or co- cultured with human BM stromal cells (EB/BM co-culture group). Flow cytometry and hematopoietic colony-forming assays were used to assess hematopoietic differentiation in the three groups. While no significant increase of CD34+/CD45- or CD34+/CD38- cells was noted in the three groups on days 3 and 5, the percentage of CD34+/CD45- cells and CD34+/ CD38- cells was significantly higher in the EB/BM co-culture group than in the EB and EB/high FBS groups on day 10. The number of colony-forming cells (CFCs) was increased in the EB/BM co-culture group on days 7 and 10, implying a possible role for human BM stromal cells in supporting hematopoietic differentiation from human ES cell-derived EBs. These results demonstrate that co-culture of human ES-cell-derived EBs with human BM stromal cells might lead to more efficient hematopoietic differentiation from human ES cells cultured alone. Further study is warranted to evaluate the underlying mechanism.

ADP-ribosyl Cyclase 1↗
PubMed2005

Phase II study with a combination of epirubicin, cisplatin, UFT, and leucovorin in advanced hepatocellular carcinoma.

PURPOSE: Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Because HCC usually presents as an advanced disease and occurs in the background of liver cirrhosis, most patients are not suitable for treatment with curative intent, thus effective systemic chemotherapy is required. However, the outcome of systemic chemotherapy has been disappointing in advanced HCC. This study was conducted to test the efficacy and toxicity of the combined regimen of epirubicin, cisplatin, and UFT moderated by leucovorin in advanced or recurrent HCC. PATIENTS AND METHODS: All 53 patients received epirubicin (50 mg/m2 i.v.) on day 1 and cisplatin (60 mg/m2 i.v.) after epirubicin administration. Oral UFT 400-600 mg/day, determined by body surface area, and leucovorin 75 mg/day were administered for 21 consecutive days, followed by a 7-day drug free interval. RESULTS: Nine had a partial response, representing 16.9% of response rate (95% confidence interval rate; 7.0-26.8%) with median response duration of 17.1 weeks (95% CI; 5.0-29.3 weeks, range; 7.1-51.7 weeks). Fifteen patients had stable disease and the disease progressed in 26 patients. The median overall survival for the patients was 24.6 weeks (95% CI; 17.3-31.9 weeks, range; 3.0-131.3 weeks). The main toxicities were hematologic toxicities including neutropenia, which reached grade 3/4 in 17 patients (38.5%), and grade 3 or 4 thrombocytopenia in five patients (9.4%). CONCLUSION: The combination of epirubicin, cisplatin, and UFT moderated by leucovorin showed modest anti-tumor activity with relatively tolerable toxicities. However, a randomized phase III trial based on this regimen is warranted to clarify its survival benefit in patients with advanced HCC.

Adult↗
PubMed2005

Autocrine vascular endothelial growth factor/vascular endothelial growth factor receptor-2 growth pathway represents a cyclooxygenase-2-independent target for the cyclooxygenase-2 inhibitor NS-398 in colon cancer cells.

OBJECTIVES: Coexpression of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-2 (VEGFR-2) has been reported in tumor cells, suggesting the presence of an autocrine VEGF/VEGFR-2 growth pathway in solid tumors. Thus, we hypothesize that the presence of this autocrine pathway in colon cancer cells may be a COX-2-independent target of COX-2 inhibitors and a mechanism behind the antitumor effects of these agents. METHODS: COX-2-positive (Caco2, HT-29) and COX-2-negative colon cancer cells (DLD-1, Hct-15) were used. Expression of VEGFR-2 was evaluated by Western blot and reverse transcriptase-polymerase chain reaction and VEGF production was measured from culture supernatant by enzyme-linked immunosorbent assay. Growth inhibition and the expression of VEGF and VEGFR-2 were compared after treatment with the COX-2 inhibitor, NS-398 at doses ranging from 5 to 100 microM. RESULTS: VEGF and VEGFR-2 were expressed in all four colon cancer cells and a blockade of VEGFR-2 with anti-VEGFR-2 antibody treatment induced growth inhibition of colon cancer cells, supporting the presence of autocrine VEGF/VEGFR-2 growth pathway. NS-398 suppressed the growth of colon cancer cells, independent of COX-2 expression. VEGFR-2 expression of tumor cells was reduced after NS-398 treatment at 100 microM, the concentration at which maximal growth inhibition was induced. The amount of VEGF in culture supernatant was increased by NS-398 at 100 microM, suggesting increased secretion of VEGF in compensation for reduced VEGFR-2 expression. CONCLUSION: The autocrine VEGF/VEGFR-2 growth pathway could be a COX-2-independent target of the COX-2 inhibitor, NS-398, in colon cancer cells.

Antineoplastic Agents↗
PubMed2005

Incidence of anemia in older Koreans: community-based cohort study.

Most epidemiologic data are related to the prevalence of anemia, and there is little information regarding the incidence or etiology of newly diagnosed anemia in older people. The purpose of this study was to define the incidence and characteristics of anemia in the elderly population of Korea. Three hundred thirty-two independent, community-living, elderly persons aged 60 years and older were enrolled, and laboratory tests including iron profiles were performed. The mean age was 72+/-4.8 years and the mean hemoglobin was 13.4+/-1.1g/dl. During the follow-up period of 3 years, 24 subjects (3 males and 21 females) were newly diagnosed with anemia, which led to a 3-year incidence of 7.2% (24/332). Among the 24 subjects with new-onset anemia, iron deficiency anemia (IDA) was diagnosed in 5 subjects, while anemia of chronic disease (ACD) was detected in 8 subjects. Underlying illnesses were diabetes mellitus, osteoarthritis, renal insufficiency, hypothyroidism and malignancy. In those subjects with new-onset anemia, the serum iron, ferritin, transferrin saturation and albumin were lower than in the normal group. In conclusion, the 3-year incidence of anemia among Korean elderly people was determined to be 7.2%, and ACD was the most commonly defined cause of anemia.

Age Distribution↗
PubMed2005

Ischemia-reperfusion injury activates innate immunity in rat kidneys.

BACKGROUND: There is growing evidence of a role of the immune system in the pathophysiology of ischemia-reperfusion (I/R) injury, but the influence of I/R injury on innate immunity is still undetermined. METHODS: Sprague-Dawley rats were used. I/R injury was induced by clamping both renal arteries for 45 min, and the rats were killed 1, 3, 5, and 7 days later. Activation of innate immunity was evaluated in terms of the expression of toll-like receptor (TLR) 2 or TLR4 mRNAs and protein, by the level of the TLR ligand (heat shock protein [HSP] 70), and maturation of dendritic cells by double-label immunohistochemistry of dendritic cells for major histocompatibility complex (MHC) class II antigen. RESULTS: I/R injury increased TLR2 and TLR4 mRNA and protein expression, and they were mainly observed on renal tubular cells. I/R injury also produced endogenous TLR ligand (HSP70) on renal tubular cells. I/R injury increased not only the numbers of dendritic cells but also the production of MHC class II antigen in dendritic cells, suggesting maturation of these cells. Activation of innate immunity was observed at day 1, peaked at days 3 to 5 after I/R injury, and thereafter gradually decreased. CONCLUSIONS: I/R injury rapidly activates the innate immune response.

Animals↗
PubMed2005

The cutoff value of serum ferritin for the diagnosis of iron deficiency in community-residing older persons.

The serum ferritin assay is the best single blood test for the diagnosis of iron deficiency. Previous studies with elderly anemic patients have suggested that ferritin level less than 45 mug/L is indicative of iron deficiency. The subjects of these studies were hospitalized patients with anemia, however. We thus conducted a prospective study to determine the normal minimum level of serum ferritin of community-dwelling older adults by assessing the ratio of serum transferrin receptor to the log ferritin level (sTfR-F index). We conducted the anemia survey between October and November 2002. A total of 1,254 apparently healthy older adults, aged between 60 and 95 years, from three urban community dwellings participated in the survey. Among these individuals, 156 subjects who were anemic or whose serum ferritin level was less than 100 microg/L were selected. The soluble transferrin receptor assay was performed and the sTfR-F index was calculated. The receiver operating characteristic curve analysis was performed. Based on the data, serum ferritin level of 22 microg/L was selected as the cutoff value for the diagnosis of iron deficiency in community-dwelling older adults. Applying the serum ferritin cutoff of 22 microg/L and the sTfR-F index cutoff of 1.5, the sensitivity of the assay was 89.5% (34 of 38) and the specificity was 89.0% (105 of 118). In conclusion, for the diagnosis of iron deficiency of community-residing older adults, we suggest the serum ferritin cutoff value of 22 microg/L obtained by use of the sTfR-F index. The value is lower than the previous value established for hospitalized and anemic older adults.

Activities of Daily Living↗
PubMed2005

Follow-up study of peripheral blood carcinoembryonic antigen mRNA using reverse transcription-polymerase chain reaction as an early marker of clinical recurrence in patients with curatively resected gastric cancer.

In this study, we evaluated the clinical significance of detecting carcinoembryonic antigen (CEA) mRNA in the peripheral blood samples of patients with gastric cancer. We analyzed the peripheral blood of 46 patients with gastric cancer who had undergone curative resection. The presence of CEA mRNA was serially monitored using a CEA-specific reverse transcription-polymerase chain reaction (RT-PCR) every 2 months. The clinical recurrence rates according to category were as follows: 100% (3 of 3) in the positive conversion, 0% (0 of 18) in the negative conversion, 50% (3 of 6) in the always-positive, and 10.5% (2 of 19) in the always-negative category. The recurrence rate was 66.7% (6 of 9) in the positive group and 5.4% (2 of 37) in the negative group (P < or =0.00022). Multiple logistic regression analysis demonstrated that only group variable had a significant effect on clinical recurrence (P = 0.015). We conclude that RT-PCR analysis of CEA mRNA in the peripheral blood seems to be a promising tool for the early detection of micrometastatic circulating tumor cells in gastric carcinoma patients and that it can be useful used to identify patients at risk for recurring.

Adult↗