Biomedical subjects

Young Choi

Publications and source records attributed to Young Choi.

9 recordsLinked to original sources

PubMed2007

Interpretation of interleukin-2 receptor alpha positive cells during induction chemotherapy for adult acute myelogenous leukaemia patients.

To correlate clinical outcomes with the expression of interleukin-2 receptor alpha (CD25) positive cells during induction chemotherapy (IC) in adult patients with acute myeloid leukaemia (AML), we investigated the prognostic importance of subsets of peripheral blood (PB) CD45+CD25+ cells. Seventy-five patients with newly diagnosed AML received the same initial IC; and serial PB samples were taken. The gated CD45/CD25 cell populations were used to compare the intensity of immunophenotypic signals based on the treatment timeline. Patients who responded poorly to IC demonstrated exceptionally higher levels of PB CD45+CD25+ cells by percentage (p = 0.003) or by absolute count (p = 0.046) on the seventh day (D + 7) of initial IC. In addition, patients in complete remission (CR) (n = 61) demonstrated relatively lower levels of steady PB CD45+CD25+ after standard IC. These results suggest that the expression of CD25 can be used to predict the response to IC during an early period of treatment.

Adolescent↗

PubMed2006

Hydrothorax in a patient with Denys-Drash syndrome associated with a diaphragmatic defect.

The Wilms tumor suppressor gene, WT1, plays an important role in the development of the urogenital system and the gonads, and clinical syndromes associated with WT1 mutations, such as WAGR syndrome, Denys-Drash syndrome and Frasier syndrome, typically manifest as renal and genitourinary abnormalities. WT1 may also play an important role in the development of the diaphragm, and recently several papers have reported an association between WT1 mutations and diaphragmatic hernias. In addition, WT1 mutations were also detected in some patients with Meacham syndrome, a rare malformation syndrome comprising congenital diaphragmatic hernia, double vagina, sex reversal, and cardiac malformations. Here, we report a case of an infant with typical clinical features of Deny-Drash syndrome and a heterozygous missense mutation, Arg366His, in the WT1 gene, in whom a diaphragm defect was detected after starting peritoneal dialysis. Diaphragmatic defects are rare but may be considered as clinical manifestations of WT1 mutation syndromes. In addition, we suggest that WT1 abnormalities should be suspected in patients with chronic renal failure who develop hydrothorax after peritoneal dialysis, especially in those with genitourinary abnormalities.

Amino Acid Substitution↗

PubMed2005

Estrogen receptor beta in breast cancer: associations between ERbeta, hormonal receptors, and other prognostic biomarkers.

The estrogen receptor (ER)-beta isoform has been recently identified to be distinct from ERalpha isoform and regulates separate sets of genes, and can exert opposite signaling functions depending on the ligand and response elements. Previous studies of ERbeta have been at the mRNA level and few by immunohistochemistry, and the results are inconsistent. In this study the authors compared expression of ERbeta with those of other prognostic biomarkers by immunohistochemistry on tissue microarray slides, and with morphologic parameters on 147 cases of primary breast cancer. Immunoreactivity of more than 10% of cancer cells was considered to be positive. Associations between categoric variables were analyzed using the chi test, and a P value less than 0.05 was considered to be significant. ERbeta was expressed in benign epithelium and stromal cells, and breast cancer cells in 59% of different histologic types of breast cancer. ERbeta was coexpressed with ERalpha in 45% of cases. There was a statistically significant association between expression of ERbeta and Her-2/neu (P<0.000), cathepsin D (P<0.02), p53 (P<0.03), and PS2 (P<0.002). Ki-67 was almost exclusively expressed in ERbeta-positive cells. No statistically significant association was seen between ERbeta expression and histologic grade, DNA ploidy, or S-phase.

Biomarkers, Tumor↗

PubMed2005

Fas, Fas-associated death domain-like interleukin 1beta-converting enzyme-like inhibitory protein, and apoptotic features of elderly acute myeloid leukemia based on response to induction chemotherapy.

A study was performed to examine the clinical outcome of triple-combination induction chemotherapy in 26 elderly Korean acute myeloid leukemia (AML) patients and to investigate apoptotic responses during and after treatment to determine whether the responses can be used as prognostic markers. Patients who had Western blot or polymerase chain reaction analysis findings of higher expression levels of Fas-associated death domain-like interleukin 1beta-converting enzyme-like inhibitory protein (FLIP) on day 7 after chemotherapy were more likely to have complete remission, but there was less or no correlation with Fas or a proapoptosis/apoptosis reaction. Expression of FLIP molecules may be, at least in part, an early prognostic indicator in the treatment of elderly AML patients.

Aged↗

PubMed2005

Primary localized laryngeal amyloidosis: report of 3 cases with long-term follow-up and review of the literature.

CONTEXT: Localized laryngeal amyloidosis is an uncommon condition with limited long-term follow-up studies. The precise etiology and pathogenesis are not entirely clear. OBJECTIVE: To further characterize the histopathologic features and possible pathogenesis of localized laryngeal amyloidosis. DESIGN: Three cases of primary localized laryngeal amyloidosis were identified at our institutions from 1980 to 2003. The clinical features and histologic and immunohistochemical patterns were evaluated. Systemic workups were pursued during the long-term follow-up. RESULTS: The common presentation of the patients was hoarseness. The lesions involved vocal cords, anterior commissure, and ventricle. Microscopically, the amyloid was present within the submucosa with an adjacent lymphoplasmacytic infiltrate. The plasma cells and amyloid demonstrated monoclonal light chain restriction in all 3 cases (2 lambda, 1 kappa). No evidence of systemic amyloidosis or an overt B-cell lymphoma was found in these patients. Two patients with long-term follow-up underwent subsequent surgical removals for multiple recurrences, which occurred within 1 year of the initial diagnosis. CONCLUSIONS: The demonstration of monoclonal light chain expression in the plasmacytic infiltrate and amyloid component in the absence of systemic lymphomas indicates that localized laryngeal amyloidosis may represent a form of benign monoclonal plasma cell dyscrasia. A close follow-up of the patients may be indicated for early detection of recurrences.

Adult↗

PubMed2004

Cloning vectors based on cryptic plasmids isolated from lactic acid bacteria: their characteristics and potential applications in biotechnology.

Lactic acid bacteria (LAB) are Gram positive bacteria, widely distributed in nature, and industrially important as they are used in a variety of industrial food fermentations. The use of genetic engineering techniques is an effective means of enhancing the industrial applicability of LAB. However, when using genetic engineering technology, safety becomes an essential factor for the application of improved LAB to the food industry. Cloning and expression systems should be derived preferably from LAB cryptic plasmids that generally encode genes for which functions can be proposed, but no phenotypes can be observed. However, some plasmid-encoded functions have been discovered in cryptic plasmids originating from Lactobacillus, Streptococcus thermophilus, and Pediococcus spp. and can be used as selective marker systems in vector construction. This article presents information concerning LAB cryptic plasmids, and their structures, functions, and applications. A total of 134 cryptic plasmids collated are discussed.

Biotechnology↗

PubMed2003

Blockade of peroxynitrite-mediated astrocyte death by manganese(III)-cyclam.

Under glucose-deprived conditions, astrocytes rapidly underwent death due to their increased susceptibility to endogenously produced peroxynitrite (Gila 31, 155-164; J. Neuroimmunol. 112, 55-62; J. Neurochem. 74, 1989-1998). In the present study, the cell membrane-permeable synthetic superoxide dismutase (SOD) mimetic cyclam manganese(III) 1,4,8,11-tetraazacyclodecane (Mn(III)-cyclam) completely inhibited the death of glucose-deprived immunostimulated astrocytes. However, the structurally related compounds Ni(II)-cyclam, Co(II)-cyclam, and H(2)-cyclam, which lacks metals, had no or a little cytoprotective effect. Of the cyclams used in this study, only Mn(III)-cyclam completely scavenged the peroxynitrite produced in glucose-deprived immunostimulated astrocytes and significantly blocked the depolarization of mitochondrial transmembrane potential in those cells. The present results suggest that cell membrane-permeable synthetic SOD mimetics such as Mn(III)-cyclam may be potential therapeutic agents for various diseases associated with the endogenous production of peroxynitrite.

Animals↗

PubMed2003

DNA hybridization electrochemical sensor using conducting polymer.

We report the use of poly(thiophen-3-yl-acetic acid 1,3-dioxo-1,3-dihydro-isoindol-2-yl ester (PTAE) for application to electrochemical hybridization sensor. A synthetic route for the thiophen-3-yl-acetic acid 1,3-dioxo-1,3-dihydro-isoindol-2-yl ester (TAE) is described, which is used as a monomer of conducting polymer sensor. A direct chemical substitution of probe oligonucleotide to good leaving group site in the PTAE is carried out on the conducting polymer film. A biological recognition can be monitored by comparison with the electrochemical signal (cyclic voltammogram) of single and double strand state oligonucleotide. The sensitivity of the electrochemical sensor is 0.62 microA/nmole and the detection limit is 1 nmole. The oxidation current of double strand state oligonucleotide is a half of that of single strand, that is corresponding to the decrease of electrochemical activity of conducting polymer with increase of stiffness of side group of the polymer. The oxidation current decreasing ratios of perfect matched and single nucleotide mismatched samples are 52 and 25-30%, respectively. The more decreasing ratio is attributable to the more steric hindrance of single nucleotide mismatched sample.

Biosensing Techniques↗

PubMed2001

Decreased expression of glutamate dehydrogenase by prolonged intake of monosodium glutamate in rat brain.

One-week-old albino female rats were kept for 1 year in equal groups with or without monosodium glutamate in their drinking water. The concentrations of the glutamate in the brain crude extracts of the monosodium glutamate treated group were twofold higher than those of the control group. There were no significant changes in body weight, brain weight, and protein content, and total RNA and DNA content also did not vary in the two groups of rats. The activities of glutamate dehydrogenase (GDH) were decreased with a 45% reduction in V(max) values in the monosodium glutamate treated group compared to those in the control group, whereas no significant changes were observed in K(m) values between the two groups. The concentration of the enzyme on the Western blot analysis was significantly decreased in the monosodium glutamate treated group, whereas the level of GDH mRNA remained unchanged, suggesting a post-transcriptional control of the expression of GDH or an increased rate of degradation of enzyme protein. These results indicate that the prolonged monosodium glutamate feeding reduces the activity of GDH and subsequently decreases the catabolism of glutamate in rat brain.

Animals↗