Biomedical subjects

Young-Kyu Park

Publications and source records attributed to Young-Kyu Park.

8 recordsLinked to original sources

PubMed2006

Towards pathogenomics: a web-based resource for pathogenicity islands.

Pathogenicity islands (PAIs) are genetic elements whose products are essential to the process of disease development. They have been horizontally (laterally) transferred from other microbes and are important in evolution of pathogenesis. In this study, a comprehensive database and search engines specialized for PAIs were established. The pathogenicity island database (PAIDB) is a comprehensive relational database of all the reported PAIs and potential PAI regions which were predicted by a method that combines feature-based analysis and similarity-based analysis. Also, using the PAI Finder search application, a multi-sequence query can be analyzed onsite for the presence of potential PAIs. As of April 2006, PAIDB contains 112 types of PAIs and 889 GenBank accessions containing either partial or all PAI loci previously reported in the literature, which are present in 497 strains of pathogenic bacteria. The database also offers 310 candidate PAIs predicted from 118 sequenced prokaryotic genomes. With the increasing number of prokaryotic genomes without functional inference and sequenced genetic regions of suspected involvement in diseases, this web-based, user-friendly resource has the potential to be of significant use in pathogenomics. PAIDB is freely accessible at http://www.gem.re.kr/paidb.

Bacteria↗

PubMed2006

Expression of survivin in gastric cancer and its relationship with tumor angiogenesis.

BACKGROUND/AIMS: Survivin, a member of inhibitors of apoptosis, has been found in various human cancers. Its expression is associated with tumor progression and adverse outcome. Angiogenesis is an essential process for the primary tumor to grow and invade the adjacent normal structures. Angiogenic factors such as vascular endothelial growth factor induce survivin expression in endothelial cells. The current study was designed to investigate the possible role of survivin and vascular endothelial growth factor status for angiogenesis in human gastric cancer. METHODS: In this study, we conducted an immunohistochemical investigation of survivin and vascular endothelial growth factor expression in 106 tissue samples obtained from gastric cancer patients undergoing surgical treatment. To assess tumor angiogenesis, microvessel density was counted by staining endothelial cells immunohistochemically using anti-CD34 monoclonal antibody. RESULTS: The positive expression of survivin and vascular endothelial growth factor in gastric cancer tissues was demonstrated in 50.0 and 69.8% of cases, respectively. The expression of survivin did not associate with vascular endothelial growth factor expression. Expression of survivin was significantly associated with tumor size, depth of invasion, lymph node metastasis, tumor stage and poor survival (P=0.011, 0.004, 0.020, 0.002, 0.046, respectively). High microvessel density was significantly associated with lymph node metastasis and poor survival (P=0.006 and 0.017, respectively). The mean microvessel density value of survivin positive tumors was 87.4+/-34.4 and significantly higher than that of survivin negative tumors (P=0.016). The mean microvessel density value of vascular endothelial growth factor positive tumors was 98.7+/-37.0 and significantly higher than that of vascular endothelial growth factor negative tumors (P=0.001). A combined analysis of survivin and vascular endothelial growth factor status showed that the mean microvessel density value of both positive tumors was 103.7+/-33.1 and significantly higher than that of both negative tumors (P<0.001). CONCLUSION: These results suggest that survivin may play an important role in carcinogenesis by stimulating tumor angiogenesis in human gastric cancer.

Adult↗

PubMed2006

Expression of cyclooxygenase-2, p53 and Ki-67 in gastric cancer.

It has been reported that p53 mutation may contribute to upregulate cyclooxygenase (COX)-2 expression that is observed in malignant tissues. These molecules are involved in carcinogenesis by affecting tumor cell proliferation. The aim of this study was to examine the relationship between COX-2 or p53 expression and clinico-pathological characteristics including tumor cell proliferation in gastric cancer. COX-2 and p53 expressions were investigated with immunostaining, in tissue specimens obtained from 119 patients who underwent surgery for gastric cancer. The Ki-67 labeling index (LI) was counted by Ki-67 immunostaining. COX-2 and p53 expressions correlated significantly with depth of tumor invasion. However, there was no association between COX-2 or p53 expression and survival. p53 expression did not correlate with COX-2 expression. There was no significant difference in various clinicopathological variables between Ki-67 LI subgroups. The mean Ki-67 LI value of COX-2 positive tumors was significantly higher than that of negative tumors. The mean Ki-67 LI value of p53 positive tumors was not significantly higher than that of negative tumors. The mean Ki-67 LI value of both COX-2 and p53 positive tumors was significantly higher than that of both negative tumors. These results imply that COX-2 expression is associated with tumor cell proliferation of gastric cancer.

Adult↗

PubMed2005

Clinicopathologic characteristics of gastric carcinoma in elderly patients: a comparison with young patients.

AIM: To examine the clinicopathologic features of elderly patients with gastric carcinoma and to investigate the relationship between prognosis and age. METHODS: We reviewed the hospital records of 2,014 patients with gastric carcinoma retrospectively to compare the clinicopathologic findings in elderly (age >70 years) and young (age <36 years) patients during the period from 1986 to 2000 in a tertiary referral center in Gwangju, Korea. Overall survival was the main outcome measure. RESULTS: Of the 2,014 patients, 194 (9.6%) were in the elderly group and 137 (6.8%) were in the young group. The elderly and young patients had similar distributions with respect to depth of invasion, nodal involvement, hepatic metastasis, peritoneal dissemination, tumor stage at the initial diagnosis, and type of surgery. Synchronous multiple carcinomas were found in 14/194 (7.2%) of the elderly group and 4/137 (2.9%) of the young group (P<0.05). Using the Borrmann classification, type IV was more frequent in the young patients than in the elderly patients (P<0.05). Significantly more elderly patients had a well or moderately differentiated histology, and more young patients had a poorly differentiated histology and signet ring cell carcinoma (P<0.001). The 5-year survival rates of elderly and young patients did not differ statistically (52.8% vs 46.5%, P = 0.5290). Multivariate analysis showed that the histologic type, nodal involvement and operative curability were significant prognostic factors, and age itself was not an independent prognostic factor of survival for elderly gastric carcinoma patients. CONCLUSION: Elderly patients with gastric carcinoma do not have a worse prognosis than young patients. The important prognostic factor is whether the patients undergo a curative resection.

Adenocarcinoma, Mucinous↗

PubMed2005

Gene expression profile analysis of mouse colon embryonic development.

During late embryogenesis, the mouse colon develops from a pseudostratified, undifferentiated endoderm to a single-layered columnar epithelium with accompanying mesenchymal maturation. To identify regulatory genetic programs underlying these morphological changes, we profiled gene expression of the developing mouse colon by microarray from embryonic day (E)13.5 to E18.5. Unbiased cluster analysis of 13,484 cDNA elements revealed two distinct groups of genes whose expression changes reflect the dynamic morphological events of the epithelium and mesenchyme during this period. Additional analyses revealed two subsets of genes whose expression is either upregulated or downregulated over the same developmental period. Of those genes whose expression increases from E13.5 to E18.5 (n = 158), known functions include acquisition and/or maintenance of colonic differentiation. Genes whose transcription is downregulated over this period (n = 49) have demonstrated roles in nuclear organization, transcriptional regulation, and cell proliferation. These results provide the basis for a molecular portrait of colonic development during late embryogenesis and should be a valuable resource for investigators interested in colonic development and neoplasia, as well as comparative organogenesis.

Animals↗

PubMed2005

Amphiregulin causes functional downregulation of adherens junctions in psoriasis.

Overexpression of amphiregulin (AR) has been linked to psoriasis in mouse and man. Since psoriasis is marked by hyperproliferation of keratinocytes and loss of epidermal barrier function with infiltration of inflammatory cells into the epidermis and dermis, we hypothesized that AR might contribute to the pathogenesis of psoriasis by affecting the integrity of cell-cell junctions. We find that there is a marked reduction of functional E-cadherin in psoriatic lesions from both INV-AR mice and individuals with psoriasis. Total E-cadherin levels are dramatically reduced in psoriatic lesions from INV-AR mice. Compared with normal skin, psoriatic lesions from individuals with psoriasis exhibit downregulation of the cytoskeletal-associated triton-insoluble pool of E-cadherin and the appearance of an 80 kDa ectodomain fragment in the cytoplasmic triton-soluble pool. There is reduced immunohistochemical staining for E-cadherin in the basal epidermis of human psoriatic lesions. Moreover, there is enhanced transmigration of human neutrophils through polarized epithelial cell monolayers of MDCK cells after administration of AR, but not transforming growth factor-alpha, further supporting a specific role for AR in the pathogenesis of psoriasis.

Adherens Junctions↗

PubMed2004

Video-assisted thoracoscopic decortication for management of postpneumonic pleural empyema.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) for decortication or debridement in the management of empyema thoracis has increased the available treatment options but requires validation. We present and evaluate our technique and experience with thoracoscopic management of pleural empyema, irrespective of chronicity. METHODS: From May 1, 2000, to April 30, 2002, VATS debridement and decortication in 70 consecutive patients presenting with pleural space infections was performed with endoscopic shaver system. A retrospective review was performed and the effect of this technique on perioperative outcome was assessed. RESULTS: The VATS evacuation of infected pleural fluid and decortication was successfully performed in 65 of 70 patients. The mean duration of preoperative symptoms before referral was 23 +/- 1.8 days. The mean duration of hospitalization before transfer was 13.5 +/- 1.5 days. Blood loss was 330 +/- 200 mL. Intercostal drainage was required for 5 +/- 3 days. The postoperative hospital stay was 5 +/- 0.7 days. There were no operative mortalities. CONCLUSIONS: Video-assisted thoracoscopic decortication with endoshaver system is a simple and effective method in the management of the fibropurulent or organic pleural empyema.

Adolescent↗

PubMed2003

Double-phase Tc-99m MIBI scintigraphy as a therapeutic predictor in patients with non-Hodgkin's lymphoma.

PURPOSE: Tc-99m MIBI is a promising agent for the functional characterization of P-glycoprotein expression and the prediction of therapeutic outcome in human tumors. The purpose of this study was to determine whether tumor clearance of Tc-99m MIBI may have a predictive value in the clinical outcome in patients with non-Hodgkin's lymphoma. METHODS: Seventeen patients with histologically proved non-Hodgkin's lymphoma underwent Tc-99m MIBI scintigraphy before starting chemotherapy. Early and late images were obtained after the injection of 740 MBq (20 mCi) Tc-99m MIBI. Tumor-to-normal soft tissue ratios were measured on early and late images, and the percentage retention (%R) was calculated. These findings were correlated with other prognostic factors. RESULTS: Of all 40 tumor lesions, 22 (55%) showed Tc-99m MIBI tumor uptake, whereas the other 18 (45%) lesions had no uptake. According to the location, the diagnostic accuracy of Tc-99m MIBI scans was 66.7% (12 of 18) for lesions of the head and neck, 66.7% (8 of 12) for those of the chest, and 20% (2 of 10) for those of subdiaphragmatic regions (P = 0.037). The mean %R of complete responders was 91.8 +/- 14.8% and for partial responders or nonresponders it was 65.4 +/- 17.7% (P = 0.014). The %R of Tc-99m MIBI showed a significant negative correlation with the serum lactate dehydrogenase level (r = -0.757), the score of the international prognostic index (r = -0.643), and the Ann Arbor stage (r = -0.733). CONCLUSION: The slow tumor clearance of Tc-99m MIBI can predict a good response to chemotherapy in patients with non-Hodgkin's lymphoma and differentiate responding and nonresponding tumors early in the course of chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗