Biomedical subjects

J Y Park

Publications and source records attributed to J Y Park.

At least 19 recordsLinked to original sources

PubMed2000

Mapping of a new target region of allelic loss at 21q22 in primary gastric cancers.

To determine the minimal region of deletion on 21q22 in gastric cancer, we performed a high-density loss of heterozygosity (LOH) study with eight polymorphic microsatellite markers. Among the 43 tumors examined, 20 (50%) of 40 informative carcinomas showed LOH at one or more loci. The peak LOH frequency was identified at D21S1820 (34.2%) in 21q22.3. This data suggests that this locus might harbor a new tumor suppressor gene in an area <0.332 Mb in physical map distance defined by D21S1820 and D21S49. Thus, we speculate that trefoil factor family 1 (TFF1), located in this narrow region, might be the most probable candidate gene involved in gastric cancer carcinogenesis.

Adenocarcinoma↗

PubMed2000

Effect of DNA topology on plasmid DNA repair in vivo.

Escherichia coli nucleotide excision repair (NER) is responsible for removing bulky DNA adducts by dual incisions of the UvrABC endonuclease. Although the activity of the UvrAB complex which can induce DNA conformational change is employed in NER, the involvement of DNA topology and DNA topoisomerases remains unclear. We examined the effect of topoisomerase inhibitions on a NER in vivo system. The repair analysis of intracellular plasmid revealed that the DNA damage on positive supercoils generated by gyrase inhibition remained unrepaired, whereas the DNA damage was repaired in topoisomerase I mutants. These results suggest that DNA topology affects the NER process and the removal of positive supercoils by gyrase is vital for the efficiency of the E. coli NER system.

DNA Polymerase I↗

PubMed2000

A distinct tumor suppressor gene locus on chromosome 15q21.1 in sporadic form of colorectal cancer.

The SM1311 family is an Ashkenazi family with dominantly inherited predisposition to colorectal adenomas and carcinomas and has a high-penetrance locus in chromosome 15q, with a multipoint logarithm of the odds score of 3.06 at marker D15S118. In the present study, we performed a high-density loss of heterozygosity study with 13 polymorphic microsatellite markers, including D15S118, spanning 15q15.3-q22.1, on 70 cases of the sporadic form of colorectal tumors. Our deletion mapping data showed a locus at D15S968 in chromosomal sub-band 15q21.1 may harbor a tumor suppressor gene in an area <0.521 Mb in physical map distance defined by markers D15S514 and D15S222. THBS1, 0.185 Mb proximal to D15S968, is the nearest known gene to this specific narrow loss of heterozygosity region. Thus, we speculate that THBS1 might be the most probable candidate gene involved in colorectal cancer carcinogenesis.

Adenocarcinoma↗

PubMed2000

Design and synthesis of some oxadiazolyl, thiadiazolyl, thiazolidinyl, and thiazolyl derivatives of 1H-pyrazole as anti-inflammatory antimicrobial agents.

Four series of 1H-pyrazole derivatives have been synthesized. The first series was prepared by cyclization of the intermediate 3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazole-4-carbaldehyde aroyl-hydrazone 4a-c with acetic anhydride to afford the corresponding oxadiazoline derivatives 5a-c. The other series were prepared by the cyclization of the intermediate 3-(5-bromo-2-thienyl)-1-phenyl-4-substituted thiocarbamoylhydrazonomethyl-1H-pyrazole 6a-c with acetic anhydride, ethyl bromoacetate or phenacyl bromide giving rise to 3-(5-bromo-2-thienyl)-1-phenyl-4-[3-acetyl-5-(N-substituted acetamido)-2,3-dihydro-1,3,4-thiadiazol-2-yl]-1H-pyrazoles 7a-c, 3-(5-bromo-2-thienyl)-1-phenyl-4-(3-substituted- 4-oxothiazolidin-2-ylidenehydrazonomethyl)-1H-pyrazoles 8a-c, or 3-(5-bromo-2-thienyl)-1-phenyl-4-(3-substituted-4- phenyl-2,3-dihydrothiazol-2-ylidenehydrazonomethyl)-1H-pyraz oles 9a-c respectively. Some of these compounds showed anti-inflammatory, antibacterial or antifungal activities comparable to that of Proquazone, Ampicillin, or Clotrimazole respectively.

Animals↗

PubMed2000

Differentiation of Salmonella enterica serotype gallinarum biotype pullorum from biotype gallinarum by analysis of phase 1 flagellin C gene (fliC).

Salmonella enterica serotype gallinarum biotype gallinarum and biotype pullorum are non-motile and pathogenic avian strains. Biotype gallinarum causes fowl typhoid and biotype pullorum is the cause of pullorum disease in chickens. The two biotypes could be differentiated based on biochemical characteristics. However, conventional culture and biochemical assays are time-consuming, laborious and need sterile laboratory practices. Although the two biotypes, gallinarum and pullorum are non-motile, they possess the phase 1 flagellin C gene. The variable regions of the flagellin C gene from 41 biotype pullorum and 52 biotype gallinarum were amplified by colony-PCR and analyzed by single strand conformational polymorphism (SSCP) method. Differences in SSCP electrophoretic patterns were confirmed by nucleotide sequencing. In addition, PCR-RFLP with Hinp1I was also successfully applied to differentiate the two biotypes. These results suggested that the variable regions of fliC could be used as a genetic marker to differentiate biotype gallinarum from biotype pullorum.

Animals↗

PubMed2000

Association between birth weight and insulin sensitivity in healthy young men in Korea: role of visceral adiposity.

Recent studies have demonstrated decreased insulin sensitivity in individuals with low birth weight. This study was performed to examine whether abdominal obesity is a link between insulin resistance and low birth weight. We studied the relationships between birth weight and insulin secretion, insulin sensitivity, and various anthropometric indices including visceral fat area in 22 healthy young Korean adults. Birth weight correlated significantly with diastolic blood pressure (r=-0.47, P<0.05) and insulin sensitivity index (S(I)) measured by a frequently sampled intravenous glucose tolerance test (FSIGT) (r=0.54, P<0.05), but not with insulin secretory indices such as acute insulin responses during FSIGT (r=-0.35, NS) or hyperglycemic clamp (r=0.17, NS) and submaximum insulin response during hyperglycemic clamp (r=0.10, NS). S(I) correlated significantly with abdominal obesity measurements such as waist circumference (r=-0.48, P<0.05), waist-to-hip ratio (r=-0.53, P<0.05) and visceral fat area (r=-0.58, P<0.01). However, we could not find significant correlation between birth weight and any of the abdominal obesity measurements (r=-0.35 for waist-to-hip ratio, r=-0.22 for visceral fat area, and r=-0.24 for visceral-to-subcutaneous fat ratio; NS for all). The present data confirm that low birth weight is associated with insulin resistance in adult life. However, our data suggest that the association between low birth weight and insulin resistance is not mediated by abdominal obesity.

Adipose Tissue↗

PubMed2000

Impact of abnormal uptakes in bone scan on the prognosis of patients with lung cancer.

The detection of bone metastases is important in the management of patients with lung cancer because bone metastasis has a major impact on the prognosis and choice of treatment modality. Bone scan has been widely used for early detection of bone metastases but its low specificity complicates confirmation of bone scan findings. To evaluate the effects of abnormal bone scan findings on the prognosis of patients with lung cancer, we retrospectively analyzed the effect of abnormal uptakes on the prognosis of patients with primary lung cancer. The overall survival of patients with abnormal bone uptake was not significantly different from those without abnormal uptake. However, the patients with more than two abnormal bone uptakes had significantly shorter survival than those with no abnormal uptake (P<0.05). To confirm the effect of abnormal bone uptakes on survival, we compared the survival curves of three patient groups without knowledge of bone scan findings: group A, stage I-IIIB with more than two abnormal bone uptakes (potential stage IV); group B, stage IIIB with no abnormal bone uptake (true stage IIIB); and group C, stage IV with no abnormal bone uptake. Group A revealed shorter survival than group B (P<0.05). But, there was no significant difference in survival times between group A and group C. In the Cox regression analysis, the presence of more than two abnormal bone uptakes was a significant prognostic factor (P=0.0277), together with performance status, stage, and albumin. These results suggest that one or two abnormal bone uptake at diagnosis did not affect overall survival of the patients, and that the patients with more than two abnormal bone uptakes are considered as clinical stage IV because of high probability of bone metastases.

Bone Neoplasms↗

PubMed2000

Prevalence and risk factors of low quantitative ultrasound values of calcaneus in Korean elderly women.

Quantitative ultrasound (QUS) of bone is a new radiation-free, low-cost method that measures both bone mass and bone quality. This study was performed to establish the normative data of QUS for Korean women and to determine the prevalence and risk factors of low quantitative ultrasound values in a Korean elderly population. We studied 238 healthy women aged 20-29 years working at a hospital, and 552 women over 50 years of age living in six villages of Chung-Up district, a rural area of South Korea, using QUS measurement of bone. Broadband ultrasound attenuation and speed of sound were measured at the calcaneus, and an index combining these factors (stiffness index) was calculated. T-score was calculated from the data of young normal subjects. Of the 552 elderly women, 34.2% had T-scores between -1.0 and -2.5, and 11.8% had T-scores below -2.5. The prevalence of low quantitative ultrasound values increased with older age, longer duration following menopause, lower body mass index, younger age at menopause and smoking. In multiple logistic regression analysis, age (odds ratio = 1.40 per 5 years, P < 0.05), duration following menopause (odds ratio = 1.35 per 5 years, P < 0.05) and body mass index (odds ratio = 0.78 per quartile, P < 0.05) were independently associated with low quantitative ultrasound values. These results suggested that quantitative ultrasound measurement of the calcaneus could be a useful tool for epidemiological surveys of bone mass.

Adult↗

PubMed2000

Metabolizing enzyme genotype and risk for upper aerodigestive tract cancer.

Genetic polymorphisms are associated with a number of enzymes involved in the metabolism of carcinogens important in the induction of upper aerodigestive tract cancer. It has been suggested that such polymorphisms may be linked to cancer susceptibility. Using a case-control molecular epidemiologic approach, the association between many of these genetic polymorphisms and susceptibility to upper aerodigestive tract cancer has been investigated in numerous studies. In this review, we summarize the findings of these studies, analyzing potential associations with upper aerodigestive tract cancer risk in terms of gene:environment interactions, genotype-induced functional defects in enzyme activity and/or expression, and the influence of race on these associations.

Carcinogens↗

PubMed2000

Absence of mutations in the kinase domain of the Met gene and frequent expression of Met and HGF/SF protein in primary gastric carcinomas.

Hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, Met, are known to play important roles in tumor cell migration, invasion, and metastasis. We analyzed the expression of these genes and the mutations in the kinase domain of the Met gene in 43 gastric carcinomas. Of the 43 cases, the Met and HGF/SF protein were expressed in 29 (67%) and 22 (51%), respectively. All of the cases with HGF/SF immunopositivity also expressed Met. Of 22 cases with HGF/SF immunopositivity, 13 (59%) expressed HGF/SF in tumor cells as well as fibroblasts. We detected no aberrant single-strand conformational polymorphism patterns, suggesting that there are no genetic alterations in the kinase domain of the Met gene. These results indicate that HGF/SF-mediated autocrine and/or paracrine stimulation and overexpression rather than structural alteration of its receptor may contribute to the development and progression of gastric carcinoma, and that expression of Met and HGF/SF may confer a growth advantage to neoplastic cells.

Adenocarcinoma↗

PubMed2000

Suppression of endogenous insulin secretion by exogenous insulin in patients with insulinoma.

OBJECTIVE: Previous studies have demonstrated that endogenous insulin secretion is not suppressed by exogenous insulin in patients with insulinoma. In this study we examined whether insulin secretion in insulinoma patients is suppressed by exogenous insulin during hypoglycaemia. SUBJECTS AND METHODS: Sixteen insulinoma patients (5 men and 11 women) and 10 normal subjects were studied. Hyperinsulinaemic glucose clamp studies were performed at both euglycaemia (4.5 mmol/l glucose) and hypoglycaemia (2.5 mmol/l glucose). RESULTS: In normal subjects, plasma C-peptide levels were suppressed by 66% during the euglycaemic hyperinsulinaemic clamps (P < 0.01). In contrast, in insulinoma patients, plasma C-peptide levels increased by 25% during the clamps (P < 0.05). In the hypoglycaemic hyperinsulinaemic clamps, plasma C-peptide levels were nearly completely (91%) suppressed in normal subjects and partially (39%) suppressed in patients with insulinoma (P < 0.01). The decrease in C-peptide levels during the hypoglycaemic clamps was > 30% in 12 (75%) of 16 insulinoma patients and > 50% in 8 (50%) patients. CONCLUSIONS: This study demonstrated that in patients with insulinoma, insulin secretion was not suppressed by exogenous insulin during euglycaemia but was suppressed during hypoglycaemia, although the degree of suppression was less than that in normal subjects. Our results suggest that the feedback regulation of insulin secretion by exogenous insulin is partially retained in patients with insulinoma.

Adult↗

PubMed2000

Increased urinary albumin excretion in Cushing's syndrome: remission after correction of hypercortisolaemia.

OBJECTIVES: Increased urinary albumin excretion (UAE) in diabetic and nondiabetic subjects is frequently associated with insulin resistance syndrome and central obesity. Cushing's syndrome is also characterized by central obesity and insulin resistance. This study was undertaken to see whether increased UAE is found in Cushing's syndrome. DESIGN: Cross-sectional study. PATIENTS: Thirteen consecutive patients with Cushing's syndrome. MEASUREMENTS: Patients collected three overnight urine samples for the measurement of UAE by radioimmunoassay. UAE was also measured in 479 nondiabetic subjects who comprised the control population for this study. In the patients who had initial microalbuminuria, UAE was remeasured 2 months after successful removal of pituitary or adrenal tumours. Kidney biopsy was performed in three patients during adrenalectomy. RESULTS: Eleven out of 13 patients (84.6%) had increased UAE (> 9.6 micrograms/min), and eight patients (61.5%) had microalbuminuria or overt proteinuria (> 20 micrograms/min). Kidney biopsy revealed apparently normal glomerular structures without evidence of diabetic nephropathy. After correction of hypercortisolaemia, UAE declined profoundly in all of the patients. CONCLUSIONS: More than 80% of patients with Cushing's syndrome had increased UAE. This was almost completely reversed after successful treatment of hypercortisolaemia. These results indicate that endogenous hypercortisolaemia increases UAE by a mechanism that is presently unknown.

Adolescent↗

PubMed2000

Somatic mutations of Fas (Apo-1/CD95) gene in cutaneous squamous cell carcinoma arising from a burn scar.

Fas (Apo-1/CD95) is a cell-surface receptor involved in cell death signaling, and recent reports have suggested that defects within the Fas receptor pathway such as Fas mutation play an important part in the development and progression of human tumors. Burn scar-related squamous cell carcinoma of skin is a unique subtype of cutaneous squamous cell carcinoma, and tends to be more aggressive in nature than conventional squamous cell carcinoma. The molecular mechanisms underlying the development and progression of burn scar-related squamous cell carcinoma, however, are not clear. In this study, we analyzed the entire coding region and all splice sites of the Fas gene for the detection of the somatic mutations in a series of 50 conventional squamous cell carcinomas and 21 burn scar-related squamous cell carcinomas by polymerase chain reaction, single strand conformation polymorphism, and DNA sequencing. We detected mis-sense mutations in three of 21 burn scar-related squamous cell carcinomas (14.3%), whereas no mutation was detected in 50 conventional squamous cell carcinomas. Of the three Fas mutations detected in the burn scar-related squamous cell carcinomas, one was found in Fas ligand-binding domain, another one was identified in the death domain known to be involved in the transduction of an apoptotic signal, and the other one was found in the transmembrane domain. Our data show that some burn scar-related squamous cell carcinomas have Fas gene mutations in important regions for the apoptosis function and suggest that these mutations might be involved in the pathogenesis of burn scar-related squamous cell carcinomas. In addition, our results provide an important clue to understanding the difference between burn scar-related squamous cell carcinoma and conventional squamous cell carcinoma at the molecular level.

Adolescent↗

PubMed2000

Association between hepatitis B virus infection and HLA-DR type in Korea.

Although the mechanism of susceptibility to chronic persistent hepatitis B virus (HBV) infection is not well clarified, immunogenetic factors of the host may have a role. Recently, a strong association between HLA-DR13 and the self-limited course of HBV infection has been reported. To determine whether the elimination of HBV is related to a particular HLA allele, we studied the HBV markers and HLA-DR phenotypes of 1,272 Koreans who had visited Yonsei University Medical Center for renal transplantation. They included 330 renal transplant donors. Subjects were categorized into 3 different groups: the "Unexposed Group" (UE; n = 946) with negative HBV markers, the "Chronic Carrier Group" (CC; n = 83), who were hepatitis B surface antigen (HBsAg)-positive, and the "Spontaneously Cleared Group" (SC; n = 243), who were HBsAg-negative with antibodies to HBsAg (anti-HBs) and hepatitis B core antigen (anti-HBc). HLA-DR4 was the most common type in all groups. HLA-DR6 was significantly more frequent in 69 of 243 subjects with SC (28. 4%) than in 8 of 83 subjects with CC (9.6%) (P <.001; relative risk [RR] = 3.72). HLA-DR9 was significantly more frequent in CC than in SC (P <.001; RR = 0.33). HLA-DR13 showed a stronger association with the clearance of HBV than the other HLA-DR6 subgroup. The distribution of HLA-DR phenotypes was similar regardless of renal disease. Our data indicate that HLA-DR6, especially HLA-DR13, is one of the host factors, which influences the immune response to HBV, and may be associated with self-elimination of HBV in Koreans.

Adult↗

PubMed2000

Quantitative analysis of eotaxin and RANTES messenger RNA in nasal polyps: association of tissue and nasal eosinophils.

OBJECTIVES/HYPOTHESIS: Nasal polyps develop in the ethmoidal and middle turbinate area, often in relation to inflammatory conditions. Their exact etiology and pathogenesis are still under debate. Histologically, the polyps are infiltrated by a number of inflammatory cells, with eosinophil predominating in most specimens. This finding suggests that the nasal polyp is an inflammatory growth that is controlled by the local environment. The chemokines eotaxin and RANTES (regulated on activation normal T cell expressed and secreted) have been postulated to be involved in the recruitment and activation of eosinophils to certain inflamed tissues. The purpose of this study was to investigate eotaxin and RANTES mRNA expression in nasal polyps and its effect on tissue and nasal eosinophils. METHODS: Nasal polyps (917 allergic and 30 nonallergic cases) were obtained from endoscopic sinus surgery, and 15 normal inferior turbinates also were taken. Immunohistochemical staining for eosinophils and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) tests for eotaxin and RANTES mRNA expression were performed, and the concentration of nasal eosinophil cationic protein (ECP) was measured. RESULTS: The amounts of eotaxin mRNA in the allergic nasal polyps were 11.4 times higher and the levels in the nonallergic polyps were 6.4 times higher than in the normal inferior turbinate. However, the RANTES mRNA expression did not show any differences among the three groups. Tissue eosinophilia and nasal ECP levels were significantly correlated with eotaxin mRNA level but not with RANTES mRNA expression. CONCLUSION: Nasal polyp eosinophilic infiltration and activation correlate mainly with increased eotaxin gene expression rather than with RANTES expression.

Adolescent↗

PubMed2000

Phylogenetic affiliation of the pseudomonads based on 16S rRNA sequence.

The broad and vague phenotypic definition allowed the genus Pseudomonas to become a dumping ground for incompletely characterized polarly flagellated, gram-negative, rod-shaped, aerobic bacteria, and a large number of species have been accommodated in the genus Pseudomonas. The 16S rRNA sequences of 128 valid and invalid Pseudomonas species, which included almost valid species of the genus Pseudomonas listed in the Approved Lists of Bacterial Names, were obtained: sequences of 59 species were determined and those of 69 species were obtained from the GenBank/EMBL/DDBJ databases. These sequences were compared with the sequences of other species of the Proteobacteria. Fifty-seven valid or invalid species including Pseudomonas aeruginosa (type species of the genus Pseudomonas Migula 1894) belonged to the genus Pseudomonas (sensu stricto). Seven subclusters were formed in the cluster of the genus Pseudomonas (sensu stricto), and the resulting clusters conformed well to the rRNA-DNA hybridization study by Palleroni (1984). The other species did not belong to the genus Pseudomonas (sensu stricto) and were related to other genera, which were placed in four subclasses of the Proteobacteria (alpha, beta, gamma and gamma-beta subclasses). Twenty-six examined species, which were not included in the cluster of the Pseudomonas (sensu stricto) and have not been transferred to other genera as yet, are listed alphabetically: 'Pseudomonas abikonensis', Pseudomonas antimicrobica, Pseudomonas beijerinckii, Pseudomonas beteli, Pseudomonas boreopolis, 'Pseudomonas butanovora', Pseudomonas carboxydohydrogena, Pseudomonas cissicola, Pseudomonas doudoroffii, Pseudomonas echinoides, Pseudomonas elongata, Pseudomonas flectens, Pseudomonas geniculata, Pseudomonas halophila, Pseudomonas hibiscicola, Pseudomonas huttiensis, Pseudomonas iners, Pseudomonas lanceolata, Pseudomonas lemoignei, Pseudomonas mephitica, Pseudomonas pictorum, Pseudomonas saccharophila, Pseudomonas spinosa, Pseudomonas stanier, Pseudomonas syzygii and Pseudomonas woodsii. The phylogenetic affiliations of these 26 pseudomonads species are shown.

Cloning, Molecular↗

PubMed2000

Effects of high-fat diet and exercise training on intracellular glucose metabolism in rats.

We examined the effects of high-fat diet (HFD) and exercise training on insulin-stimulated whole body glucose fluxes and several key steps of glucose metabolism in skeletal muscle. Rats were maintained for 3 wk on either low-fat (LFD) or high-fat diet with or without exercise training (swimming for 3 h per day). After the 3-wk diet/exercise treatments, animals underwent hyperinsulinemic euglycemic clamp experiments for measurements of insulin-stimulated whole body glucose fluxes. In addition, muscle samples were taken at the end of the clamps for measurements of glucose 6-phosphate (G-6-P) and GLUT-4 protein contents, hexokinase, and glycogen synthase (GS) activities. Insulin-stimulated glucose uptake was decreased by HFD and increased by exercise training (P < 0.01 for both). The opposite effects of HFD and exercise training on insulin-stimulated glucose uptake were associated with similar increases in muscle G-6-P levels (P < 0.05 for both). However, the increase in G-6-P level was accompanied by decreased GS activity without changes in GLUT-4 protein content and hexokinase activities in the HFD group. In contrast, the increase in G-6-P level in the exercise-trained group was accompanied by increased GLUT-4 protein content and hexokinase II (cytosolic) and GS activities. These results suggest that HFD and exercise training affect insulin sensitivity by acting predominantly on different steps of intracellular glucose metabolism. High-fat feeding appears to induce insulin resistance by affecting predominantly steps distal to G-6-P (e.g., glycolysis and glycogen synthesis). Exercise training affected multiple steps of glucose metabolism both proximal and distal to G-6-P. However, increased muscle G-6-P levels in the face of increased glucose metabolic fluxes suggest that the effect of exercise training is quantitatively more prominent on the steps proximal to G-6-P (i.e., glucose transport and phosphorylation).

Animals↗

PubMed2000

Development of a modified three-stage methane production process using food wastes.

A modified three-stage system was developed for the rapid production of methane from food wastes. The primary stage was a semianaerobic hydrolysis/acidogenic system, in which approx 4100 mg/L of volatile fatty acids (VFAs) was produced at a hydraulic retention time (HRT) of 2 d. The operation temperature and pH were 30 degrees C and 5.0-5.5, respectively. The non-degraded materials were removed through a hole at the bottom of the reactor. The secondary stage was an anaerobic acidogenic system equipped with an upflow anaerobic sludge blanket (UASB) type of fermentor. VFA was accumulated up to 6100 mg/L by the addition of Clostridium butyricum to the reactor at an HRT of 2 d. The optimum temperature and pH range were 35 degrees C and 5.0-5.5, respectively. The tertiary methanogenic stage produced CH4 and CO2 from the VFA in the UASB reactor. Methane content was 72% of the total gas volume, and the yield was 0.45-0.50 m3/kg of volatile solids at an HRT of 12 d. The operation temperature and pH were 41 degrees C and 7.6-7.9, respectively. The three-stage process exhibited an unusually high total chemical oxygen demand reduction rate up to 95%. Total nitrogen decreased to 96% and < 10 mg/L of total phosphorus remained in the final effluent.

Aerobiosis↗