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Biomedical subjects

D K Yoon

Publications and source records attributed to D K Yoon.

11 recordsLinked to original sources
PubMed2007

Prevalence and trends of metabolic syndrome in Korea: Korean National Health and Nutrition Survey 1998-2001.

BACKGROUND: Metabolic syndrome (MetS) is a major international health problem. Limited information is available about the prevalence of MetS in Asia, especially in Korea. OBJECTIVE: To examine the prevalence and trends of MetS in a Korean population. In addition, we investigated the risk factors associated with MetS. DESIGN AND PARTICIPANTS: A total of 7445 participants aged >/=20 years from the Korean National Health and Nutrition Survey (KNHNS) 1998 and 5964 participants from the KNHNS 2001 were included in this analysis. The KNHNS is a cross-sectional health survey of a nationally representative sample of the Korean population. The prevalence of MetS was determined using the National Cholesterol Education Program Adult Treatment Panel III criteria and the Asia-Pacific criteria for obesity based on waist circumference (APC-WC). RESULTS: Using the ATP III criteria, the age-adjusted prevalence of MetS among Korean adults was 15.7% (13.7% male, 17.8% female) in 1998 and 14.4% (13.0% male, 16.2% female) in 2001. Using the APC-WC criteria, the prevalence was 21.6% (19.4% male, 23.9% female) in 1998 and 21.4% (20.1% male, 23.4% female) in 2001. Of the five MetS components, increasing trends were found between 1998 and 2001 in the prevalence of hypertriglyceridaemia, low high-density lipoprotein cholesterol and central obesity for both men and women. Age, sex, body mass index and a family history of diabetes were associated with MetS. CONCLUSIONS: These results from a representative sample show that MetS is common in Korean adults. A systemic public health programme is required to prevent future increases in diabetes and cardiovascular complications.

Adult↗
PubMed2006

Prevalence of diabetes and impaired fasting glucose in Korea: Korean National Health and Nutrition Survey 2001.

OBJECTIVE: The purpose of this study was to estimate the prevalence of diabetes and impaired fasting glucose (IFG) and their association with risk factors in the Korean population. RESEARCH DESIGN AND METHODS: The Korean National Health and Nutrition Survey 2001 was a nationally representative survey with a stratified multistage sampling design. Data from a comprehensive questionnaire, a physical examination, and blood tests were obtained from 5,844 Korean adults (2,513 men and 3,331 women) aged >20 years. RESULTS: The age-adjusted prevalence of diabetes in this Korean population was 7.6%, and the age-adjusted prevalences of previously diagnosed diabetes and newly diagnosed diabetes were 4.4 and 3.3%, respectively (fasting plasma glucose > or = 7.0 mmol/l). Overall, these results indicate that 8.1% or 1.4 million Korean men and 7.5% or 1.3 million Korean women have diabetes. The age-adjusted prevalence of IFG was 23.9%, using the new American Diabetes Association criteria (fasting plasma glucose 5.6-6.9 mmol/l). Diabetes prevalence increased with age and peaked in the oldest age-group; however, IFG prevalence did not show the same trend. Diabetes was found to be associated with age, BMI, blood pressure, triglyceride, HDL cholesterol, education levels, alcohol consumption, exercise, and a family history of diabetes. CONCLUSIONS: This study shows that diabetes and IFG are common in Korea, and about one-half of diabetes cases remain undiagnosed. These results emphasize the need to develop an urgent public program to improve the detection, prevention, and treatment of diabetes.

Adult↗
PubMed2002

Segregation in binary mixtures under gravity.

We employ kinetic theory for a binary mixture to study segregation by size and/or mass in a gravitational field. Simple segregation criteria are obtained for spheres and disks that are supported by numerical simulations.

Journal Article↗
PubMed2001

Chronological changes of N-methyl-D-aspartate receptors and excitatory amino acid carrier 1 immunoreactivities in CA1 area and subiculum after transient forebrain ischemia.

We investigated changes of immunoreactivities of N-methyl-D-aspartate receptor (NR) and of excitatory amino acid carrier 1 (EAAC-1), the neuronal glutamate transporter, in the vulnerable CA1 area and the less vulnerable subiculum of the gerbil hippocampus at various times following transient forebrain ischemia. At 30 min after ischemia-reperfusion, the intensity of NR immunoreactivity increased markedly in neurons of CA1 and subiculum, particularly NR2A/B, while EAAC-1 immunoreactivity was reduced in CA1. At 3 hr after reperfusion, the density of NR1 immunoreactivity markedly decreased in CA1. In contrast EAAC-1 immunoreactivity increased in CA1 and in the subiculum. At 12 hr after reperfusion, the decrease of NR1 immunoreactivity was not detected whereas EAAC-1 immunoreactivities in the CA1 area were intensified. In the subiculum, both NR subunits immunoreactivities decreased significantly, in contrast to the maintenance of EAAC-1 immunoreactivity. At 24 hr after reperfusion, both NR2A/B and EAAC-1 immunoreactivities decreased markedly in CA1 and subiculum. We tentatively suggest that the increase of NR immunoreactivity in CA1 at early times after ischemia-reperfusion may increase the delayed neuronal death, and that the increase or maintenance of EAAC-1 immunoreactivity at early times after ischemia-reperfusion may be an important factor in survival of neurons.

Amino Acid Transport System X-AG↗
PubMed2000

Adenovirus-mediated suicide-gene therapy using the herpes simplex virus thymidine kinase gene in cell and animal models of human prostate cancer: changes in tumour cell proliferative activity.

OBJECTIVES: To determine the feasibility and efficacy of suicide-gene therapy using adenovirus (Ad)-mediated herpes simplex virus thymidine kinase (HSV-TK) and the prodrug acyclovir, and to evaluate changes in the biological phenotype for tumour cell proliferative activity after suicide-gene therapy in animal models of human prostate cancer. MATERIALS AND METHODS: Using a replication-defective adenoviral vector (cytomegalovirus, CMV) containing the beta-galactosidase gene (Ad-CMV-beta-gal) as a control and Ad-CMV-TK as the therapeutic vector under the transcriptional control of the CMV promoter, transduction efficiency was assessed in vitro by infecting LNCaP and PC-3 androgen-dependent and independent human prostate cancer cells with Ad-CMV-beta-gal, and using X-gal staining. The TK activity in prostate cancer cells infected with Ad-CMV-TK was determined by measuring TK-mediated [3H]-gancyclovir phosphorylation. The sensitivity of LNCaP and PC-3 cells to Ad-CMV-TK in vitro was determined after infection with the therapeutic vector with or without acyclovir. The inhibition of PC-3 tumour growth in vivo induced by the Ad-CMV-TK/acyclovir suicide-gene system was assessed in separate and controlled experiments using human prostate cancer mouse models. Ki-67 proliferative antigen and proliferating cell nuclear antigen (PCNA), both useful proliferative indices, were evaluated using immunohistochemical staining (MIB-1 monoclonal antibody and monoclonal anti-PCNA antibody) in formalin-fixed, paraffin-embedded tissues from gene therapy-treated and control animals. RESULTS: The mean TK activity was significantly higher in LNCaP and PC-3 cells infected with Ad-CMV-TK than in cells infected with Ad-CMV-beta-gal, used as a control (P < 0.05). The growth of human prostate cancer cells with Ad-CMV-TK was significantly inhibited by adding acyclovir in vitro (P < 0.05). In the in vivo experiments using the PC-3 human prostate cancer mouse model, tumour volume and growth was lower in mice treated with Ad-CMV-TK/acyclovir than in those treated with Ad-CMV-TK only, acyclovir only or untreated (controls) (P < 0.05). Histochemical staining of tumour tissues showed that Ad-CMV-TK/acyclovir destroyed PC-3 tumours through tumour cell death and apoptosis, with local lymphatic infiltration. The mean PCNA labelling index in prostate cancer cells of mice treated with Ad-CMV-TK/acyclovir was significantly lower than that in untreated controls (P < 0.05, Mann-Whitney U-test). The Ki-67 labelling index in prostate cancer cells of mice treated with Ad-CMV-TK/acyclovir was also lower than that in untreated controls (P < 0.05, Student's t-test). Adenovirus-mediated suicide-gene therapy using the HSV-TK gene decreased the proliferative activity of PC-3 human prostatic cancer cells in vivo. CONCLUSIONS: Adenovirus-mediated suicide-gene therapy using an HSV-TK/acyclovir system provided effective therapy in an experimental human prostate cancer mouse model, by significantly inhibiting tumour growth and decreasing the proliferative activity of human prostate cancer cells. Such therapy could be developed as a novel method for treating patients with androgen-independent prostate cancer.

Animals↗
PubMed1999

Prostate-specific antigen adjusted for the transition zone volume versus free-to-total prostate-specific antigen ratio in predicting prostate cancer.

BACKGROUND: We performed this study to assess the efficacy of prostate-specific antigen adjusted for the transition zone volume (PSATZ) and free-to-total prostate-specific antigen (PSA) ratio (F/T ratio) in predicting prostate cancer in men with intermediate PSA levels of 4.1-10.0 ng/mL. METHODS: Between March 1997 and September 1998, PSATZ was obtained from 67 patients who underwent ultrasonography guided systemic sextant biopsies and had a PSA of 4.1-10.0 ng/mL. PSATZ was compared with F/T ratio via receiver operating characteristic (ROC) curves. RESULTS: Of 67 patients, 22 (32.8%) had prostate cancer and 45 (67.2%) had benign prostatic hyperplasia (BPH) on pathologic examination. Mean PSA, PSA density, F/T ratio and PSATZ were 7.96+/-2.01ng/mL, 0.28+/-0.14 ng/mL/cc, 0.10+/-0.06 and 0.70+/-0.28 ng/mL/cc in patients with prostate cancer and 6.39+/-1.68 ng/mL, 0.16+/-0.06 ng/mL/cc, 0.15+/-0.05 and 0.29+/-0.10 ng/mL/cc in patients with BPH, respectively. The ROC curve analysis demonstrated that PSATZ predicted the biopsy outcome significantly better than F/T ratio in all 67 patients (P<0.01) and in a subset of 53 men with normal digital rectal examination (P<0.01). With a cut-off value of 0.35 ng/mL/cc, PSATZ had a sensitivity of 86% and a specificity of 89% for predicting prostate cancer. CONCLUSIONS: These results suggest that PSATZ and F/T ratio may be useful in diagnosing prostate cancer with intermediate levels of PSA. Prostate-specific antigen adjusted for the transition zone volume is more accurate than F/T ratio in distinguishing benign prostatic disease from prostate cancer. But large prospective studies are required to assess the precise role of PSATZ and F/T ratio in early prostate cancer detection.

Age Factors↗
PubMed1995

Malignant inverted papilloma of the urinary bladder: the histopathological aspect of malignant potential of inverted papilloma.

To investigate the histopathological characteristics of inverted papillomas of the urinary bladder, including the possibility of malignant transformation, we studied the indicators of cellular proliferation activity in 7 inverted papillomas of the bladder including two cases of malignant inverted papilloma of the bladder. PCNA expression rates in two cases of malignant inverted papilloma were higher than in benign inverted papillomas. Mean numbers of AgNORs per nucleus in malignant inverted papillomas were much more than in benign inverted papillomas. The c-erbB-2 oncoprotein was expressed only in malignant inverted papillomas. These results suggest that PCNA expression rate, mean number of AgNORs per nucleus and c-erB-2 oncoprotein expression may be merited as good indicators to detect the inverted papilloma with more proliferative and aggressive lesions, and with the potential of malignant transformation.

Adult↗
PubMed1977

Emphysematous pyelonephritis.

We herein describe 2 cases of emphysematous pyelonephritis, which can be added to the 42 cases previously reported. Both female patients were diabetic and had Escherichia coli infections. Both had ureteral obstruction and underwent nephrectomy to survive septic and/or azotemic crises. Timely surgical intervention after unsuccessful antibiotics and conventional medical measurements is life-saving.

Adult↗
PubMedDate not supplied

Unusual renal cell carcinomas: a pictorial essay.

Renal cell carcinoma (RCC) is the most common solid renal neoplasm. Clear cell (conventional) carcinoma is the most common pathologic subtype of RCC. Usually RCC is a hypervascular, solid, solitary mass with contour bulging. However, RCC can manifest different features according to the pathologic tumor subtypes. Preoperative diagnosis of cyst-associated RCC is very difficult, especially in cases of RCC originating in a cyst. Multiple or bilateral presentation of RCC occurs in fewer than 5% of cases. In addition, RCCs may demonstrate unusual findings such as infiltrative growth mimicking transitional cell carcinoma, fatty component mimicking angiomyolipoma, severe perinephric infiltration, and extensive calcifications mimicking inflammation or other tumor. RCCs can be associated with hereditary diseases such as von Hippel-Lindau disease. Familiarity with these radiologic features of unusual RCCs can help ensure correct diagnosis and proper management.

Adult↗