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Biomedical subjects

H K Lee

Publications and source records attributed to H K Lee.

At least 37 records · Page 2Linked to original sources
PubMed2005

Acute renal failure related to intravenous immunoglobulin infusion in an elderly woman.

Intravenous immunoglobulin infusion induces acute renal failure via a mechanism of osmotic nephrosis. Most reported cases are related to the use of sucrose-based intravenous immunoglobulin. Maltose-based intravenous immunoglobulin is thought to be a safer alternative and have a lower risk of renal toxicity than sucrose-based preparations. Maltase, but not sucrase, is present in the brush border of proximal convoluted renal tubules, where the maltose is metabolised. We report a case of maltose-based intravenous immunoglobulin-induced acute renal failure in an elderly diabetic woman. In this case, the risk factors included advanced age, hypovolaemia, sepsis, diabetes mellitus, and the high infusion rate of the intravenous immunoglobulin. Maltase is readily inhibited by hyperglycaemia; therefore, poor glycaemic control may predispose patients to develop acute renal failure even with the better-tolerated maltose-based intravenous immunoglobulin.

Acute Kidney Injury↗
PubMed2004

The influence of plasticizers on the release of theophylline from microporous-controlled tablets.

The aim of present work was to investigate the influence of plasticizer on the release of theophylline from microporous-controlled tablets. Three plasticizers, acetyltributyl citrate (ATBC), castor oil, and triacetin, were included in this study. These plasticizers reduced the crystallinity of poly(epsilon-caprolactone) (PCL)/poly(ethylene glycol) (PEG)-blended films, and the most prominent change of enthalpy of fusion was the film plasticized by triacetin. This might be due to triacetin penetrating into both PCL and PEG domains. However, the lipophilic property of castor oil only allowed it to alter the crystallization of hydrophobic PCL domain. The Young's modulus and the tensile strength of films showed a decreased tendency while increasing the amount of plasticizer. The change of elongation of plasticized blended films was irregular and was dependent of the type of plasticizer. The size of micropores formed in the presence of plasticizer was larger than those micropores formed in its absence. The fatty plasticizer, castor oil, altered the thermal and mechanical performance and pore size of films via soluble in PCL domain, which resulted in the release of theophylline from castor oil plasticized-coated tablets, which in turn enhanced and closed to a constant release pattern.

Caproates↗
PubMed2004

Steady-state solutions of hydrodynamic traffic models.

We investigate steady-state solutions of hydrodynamic traffic models in the absence of any intrinsic inhomogeneity on roads such as on-ramps. It is shown that typical hydrodynamic models possess seven different types of inhomogeneous steady-state solutions. The seven solutions include those that have been reported previously only for microscopic models. The characteristic properties of wide jam such as moving velocity of its spatiotemporal pattern and/or out-flux from wide jam are shown to be uniquely determined and thus independent of initial conditions of dynamic evolution. Topological considerations suggest that all of the solutions should be common to a wide class of traffic models. The results are discussed in connection with the universality conjecture for traffic models. Also the prevalence of the limit-cycle solution in a recent study of a microscopic model is explained in this approach.

Journal Article↗
PubMed2004

Common genetic polymorphisms in the promoter of resistin gene are major determinants of plasma resistin concentrations in humans.

AIMS/HYPOTHESIS: Resistin is thought to be an important link between obesity and insulin resistance. It has been suggested that genetic polymorphism in the promoter of resistin gene is a determinant of resistin mRNA expression and possibly associated with obesity and insulin resistance. In this study, we investigated the association between the genotype of resistin promoter and its plasma concentrations. METHODS: We examined g.-537A>C and g.-420C>G polymorphisms in the resistin promoter and measured plasma resistin concentrations in Korean subjects with or without Type 2 diabetes. We also did haplotype-based promoter activity assays and the gel electrophoretic mobility shift assay. RESULTS: The -420G and the -537A alleles, which were in linkage disequilibrium, were associated with higher plasma resistin concentrations. Individuals with haplotype A-G (-537A and -420G) had significantly higher plasma resistin concentrations than the others. Haplotype A-G had modestly increased promoter activity compared to the other haplotypes. Electrophoretic mobility shift assay showed that the -420G allele is specific for binding of nuclear proteins from adipocytes and monocytes. However, none of the two polymorphisms were associated with Type 2 diabetes or obesity in our study subjects. CONCLUSIONS/INTERPRETATION: Polymorphisms in the promoter of resistin gene are major determinants of plasma resistin concentrations in humans.

Aged↗
PubMed2004

Multifactor-dimensionality reduction shows a two-locus interaction associated with Type 2 diabetes mellitus.

AIMS/HYPOTHESIS: Type 2 diabetes mellitus is a complex genetic disease, which results from interactions between multiple genes and environmental factors without any single factor having strong independent effects. This study was done to identify gene to gene interactions which could be associated with the risk of Type 2 diabetes. METHODS: We genotyped 23 different loci in the 15 candidate genes of Type 2 diabetes in 504 unrelated Type 2 diabetic patients and 133 non-diabetic control subjects. We analysed gene to gene interactions among 23 polymorphic loci using the multifactor-dimensionality reduction (MDR) method, which has been shown to be effective for detecting and characterising gene to gene interactions in case-control studies with relatively small samples. RESULTS: The MDR analysis showed a significant gene to gene interaction between the Ala55Val polymorphism in the uncoupling protein 2 gene ( UCP2) and the 161C>T polymorphism in the exon 6 of peroxisome proliferator-activated receptor gamma ( PPARgamma) gene. This interaction showed the maximum consistency and minimum prediction error among all gene to gene interaction models evaluated. Moreover, the combination of the UCP2 55 Ala/Val heterozygote and the PPARgamma 161 C/C homozygote was associated with a reduced risk of Type 2 diabetes (odds ratio: 0.51, 95% CI: 0.34 to 0.77, p=0.0016). CONCLUSIONS/INTERPRETATION: Using the MDR method, we showed a two-locus interaction between the UCP2 and PPARgamma genes among 23 loci in the candidate genes of Type 2 diabetes. The determination of such genotype combinations contributing to Type 2 diabetes mellitus could provide a new tool for identifying high-risk individuals.

Aged↗
PubMed2004

Laparoscopic repair of various types of biliary-enteric fistula: three cases.

Biliary-enteric fistula is one of the reasons for converting from laparoscopic cholecystectomy (LC) to open surgery. Here we present three cases of various types of biliary-enteric fistula treated successfully by laparoscopic surgery. Two cases were diagnosed preoperatively, and the remaining case intraoperatively. The first patient had a cholecystoduodenal fistula with a common bile duct stone. The second patient had cholecystocolic and choledochoduodenal fistulas with a common bile duct stone, and the third patient had a cholecystogastric fistula. The fistulas were repaired laparoscopically by intracorporeal suturing or with an endoscopic linear stapling device. All the patients had good postoperative courses without any postoperative complication. Our experience has shown us that with advances in surgical skills and instruments, laparoscopic surgery for biliary-enteric fistula can be adopted as the first treatment choice regardless of the preoperative diagnosis.

Biliary Fistula↗
PubMed2004

Treatment of vancomycin-intermediate Staphylcoccus aureus endocarditis with linezolid.

We report a case of infective endocarditis due to vancomycin-intermediate Staphylococcus aureus that developed after repeated courses of vancomycin. The patient had underlying end stage renal disease and dissecting aortic aneurysm with aortic graft and prosthetic aortic valve replacement. He responded to prolonged combination therapy with linezolid and amikacin without undergoing surgical intervention.

Acetamides↗
PubMed2004

Effect of etomidate on endothelium-dependent relaxation induced by acetylcholine in rat aorta.

The goals of this in vitro study were to investigate effects of etomidate on endothelium-dependent relaxation induced by acetylcholine in rat aorta, and to elucidate the associated cellular mechanism. In endothelium-intact rings precontracted with phenylephrine 10(-6) M, dose-response curves for acetylcholine (10(-9) to 10(-5) M) and calcium ionophore (10(-9) to 10(-6) M) were generated in the presence and absence of etomidate (5 x10(-6) 10(-5) M). In endothelium-intact or -denuded rings precontracted with phenylephrine 10(-6) M, sodium nitroprusside (10(-9) to 10(-6) M) dose-response curves were generated in the presence and absence of etomidate (10(-5)M). Etomidate (5 x10(-6), 10(-5)M) produced a significant rightward shift in the dose-response curves induced by acetylcholine (receptor-mediated endothelium-dependent agonist) and calcium ionophore A23187 (non receptor-mediated endothelium-dependent agonist). Etomidate (10(-5)M) had no effect on sodium nitroprusside (endothelium-independent nitric oxide donor)-induced vasorelaxant response in both endothelium-intact and -denuded rings. These results indicate that etomidate at clinically relevant concentrations attenuates endothelium-dependent relaxation induced by acetylcholine by an acting at a site distal to the endothelial muscarinic receptor, but proximal to guanylate cyclase activation of vascular smooth muscle in rat aorta.

Acetylcholine↗
PubMed2004

Hydrocele of the canal of Nuck in a girl: ultrasound and MR appearance.

Hydrocele of the canal of Nuck is a rare condition in females. A small evagination of parietal peritoneum forms the canal of Nuck. Failure of complete obliteration of the canal results in either an indirect inguinal hernia or a hydrocele of the canal of Nuck. We present a case in a 7-year-old girl. On ultrasound, there was a comma-shaped cyst with the tail directed cranially toward the inguinal canal. The cyst had no internal echoes and demonstrated increased through transmission. Coronal and axial MR showed a thin walled cystic mass.

Child↗
PubMed2004

Characterization of quantitative trait loci for growth and meat quality in a cross between commercial breeds of swine.

A three-generation resource family was created by crossing two Berkshire grandsires with nine Yorkshire granddams to identify QTL affecting growth, body composition, and meat quality. A total of 512 F2 offspring were evaluated for 11 traits related to growth and body composition and 28 traits related to meat quality. All animals were initially genotyped for 125 markers across the genome. The objectives of this advanced phase of the project were to further identify and characterize QTL after genotyping for another 33 markers in special regions of interest, and to develop and apply methods for detecting QTL with parent-of-origin effects. New marker linkage maps were derived and used in QTL analysis based on line-cross least squares regression-interval mapping. A decision tree for identifying QTL with parent-of-origin effects was developed based on tests against the Mendelian mode of expression. Empirical significance thresholds were derived at chromosomewise and genomewise levels using specialized permutation strategies to create data under the null hypothesis appropriate for each test. Significance thresholds derived by the permutation tests were validated based on simulation of a pedigree and data structure similar to the Berkshire-Yorkshire population. The addition of 33 markers resulted in the discovery of 29 new QTL at the 5% chromosomewise level using the Mendelian model of analysis. Thirteen of the original QTL were no longer significant at the 5% chromosomewise level. A total of 33 QTL with parent-of-origin effects were identified, including QTL with paternal expression for backfat and loin muscle area on chromosome 2, near IGF2, and QTL with maternal expression for drip loss and reflectance on chromosome 9. Tests for imprinting against Mendelian expression identified much fewer QTL with parent-of-origin effects than tests based on significance of paternal and maternal alleles, which have been used in other studies. The detected QTL and their identified mode of expression will allow further research in these QTL regions and their utilization in marker-assisted improvement of meat quality.

Adipose Tissue↗
PubMed2004

The effect of nitrogen supplementation on the efficiency of colour and COD removal by Malaysian white-rot fungi in textile dyeing effluent.

White-rot fungi, namely Coriolus versicolor and Schizophyllum commune, were studied for the biodecolorization of textile dyeing effluent in shaker-flask experiments. The results showed that C. versicolor was able to achieve 68% color removal after 5 days of treatment while that of S. commune was 88% in 9 days. Both fungi achieved the above results in non-sterile condition with diammonium hydrogen phosphate as the nutrient supplement. On the other hand, the best COD removal of 80% was obtained with C. versicolor in 9 days in sterile effluent with yeast extract as nutrient supplement, while S. commune was able to remove 85% COD within 8 days in non-sterile textile effluent supplemented with diammonium hydrogen phosphate.

Basidiomycota↗
PubMed2003

A simple method for DNA extraction from marine bacteria that produce extracellular materials.

We present a simple method for extracting DNA from the marine bacteria Hahella chejuensis, a Streptomyces sp., and a Cytophaga sp. Previously, DNA purification from these strains was hindered by the presence of extracellular materials. In our extraction method, the marine bacteria are lysed by freezing and grinding in liquid nitrogen, and treated with SDS. The extracted DNA is purified using a phenol/chloroform mixture, and precipitated in isopropanol. The extracted DNA is of high quality and suitable for molecular analyses, such as PCR, restriction enzyme digestion, genomic DNA blot hybridization, and genomic DNA library construction. We used this method to extract genomic DNA from several other marine bacteria. Our method is a reproducible, simple, and rapid technique for routine DNA extractions from marine bacteria. Furthermore, the low cost of this method makes it attractive for large-scale studies.

Bacteria↗
PubMed2003

Bioinformatic analysis of autism positional candidate genes using biological databases and computational gene network prediction.

Common genetic disorders are believed to arise from the combined effects of multiple inherited genetic variants acting in concert with environmental factors, such that any given DNA sequence variant may have only a marginal effect on disease outcome. As a consequence, the correlation between disease status and any given DNA marker allele in a genomewide linkage study tends to be relatively weak and the implicated regions typically encompass hundreds of positional candidate genes. Therefore, new strategies are needed to parse relatively large sets of 'positional' candidate genes in search of actual disease-related gene variants. Here we use biological databases to identify 383 positional candidate genes predicted by genomewide genetic linkage analysis of a large set of families, each with two or more members diagnosed with autism, or autism spectrum disorder (ASD). Next, we seek to identify a subset of biologically meaningful, high priority candidates. The strategy is to select autism candidate genes based on prior genetic evidence from the allelic association literature to query the known transcripts within the 1-LOD (logarithm of the odds) support interval for each region. We use recently developed bioinformatic programs that automatically search the biological literature to predict pathways of interacting genes (PATHWAYASSIST and GENEWAYS). To identify gene regulatory networks, we search for coexpression between candidate genes and positional candidates. The studies are intended both to inform studies of autism, and to illustrate and explore the increasing potential of bioinformatic approaches as a compliment to linkage analysis.

Autistic Disorder↗
PubMed2003

Renal perfusion abnormality. Coded harmonic angio US with contrast agent.

PURPOSE: Coded harmonic angio (CHA) US is a recently developed technique that can depict the effects of contrast agents. The purpose of this study was to determine the role of this technique in depicting the enhancement patterns of various renal perfusion abnormalities compared with dynamic CT. MATERIAL AND METHODS: During a 6-month period, various renal lesions including renal cell carcinoma (n=12), transitional cell carcinoma (n=5), acute pyelonephritis (n=5), and renal trauma (n=2) were evaluated with CHA US using a microbubble contrast agent. US images were obtained before contrast administration and with a bolus injection of 4 g of microbubble contrast agent (300 mg/ml) every 10 s for 1 min and every minute for 5 min. The contrast enhancement patterns of various renal masses were compared with dynamic CT. RESULTS: Of 12 renal cell carcinomas, 9 (75%) showed heterogeneous enhancement and the remaining 3 (25%) showed homogeneous enhancement. Enhancement of more than adjacent renal parenchyma was seen 16-252 s after injection. The duration of enhancement was 13-208 s (mean, 80 s). All transitional cell carcinomas showed peripheral enhancement. Enhancement was seen 22-270 s after injection. The duration of enhancement was 191-238 s (mean, 291 s). Five patients with acute pyelonephritis and 2 with renal trauma showed focal perfusion defects not shown on the pre-contrast examinations. CONCLUSION: CHA US with microbubble contrast agent is an effective US technique for the evaluation of both tumor vascularity and renal perfusion abnormality.

Adult↗
PubMed2002

Role of planned neck dissection for advanced metastatic disease in tongue base or tonsil squamous cell carcinoma treated with radiotherapy.

OBJECTIVE: At the conclusion of this article, the reader should be able to discuss the need for planned neck dissection for advanced cervical diseases in the tongue base and tonsil cancer after treatment with radiotherapy. BACKGROUND: In the past 5 years, we have treated patients with squamous cell carcinoma of the tonsil and tongue base with radiotherapy as the primary therapeutic modality. A planned complete neck dissection was performed on all patients with N2 or greater cervical disease regardless of response to radiotherapy. Composite resection was performed when there was persistent disease at the primary site. Although the "radiation-first" therapeutic approach for tongue base and tonsil cancer is widely accepted, the planned neck dissection for neck metastases remans controversial. The objective of the study was to determine the validity of planned neck dissection after radiotherapy for N2 disease. METHODS: Medical records of patients with primary squamous cell carcinoma of the tongue base and tonsil with neck metastasis staged N2 or greater were reviewed. Between 1994 and 1999, 36 such patients were treated with curative radiation therapy. Response was assessed 6 to 8 weeks after completion of treatment with clinical examination and CT imaging. All patients underwent planned neck dissection. We reviewed the clinical and radiographic response of neck disease to radiotherapy as it correlated with the histopathologic findings. RESULTS: Of the 36 patients, 17 had clinical and CT evidence of persistent disease. In this group, 65% had pathologically confirmed diseases at surgery. Of the 9 patients with no evidence of disease on clinical examination, negative biopsy at the primary site, and a negative CT scan, 33% (three of nine) still had residual disease in the neck dissection specimen. CONCLUSIONS: Positive findings on clinical examination and CT can predict the presence of malignancy after radiation therapy. However, a negative CT and clinical examination are limited in predicting a complete response. These data lend support to the role of planned neck dissection after radiotherapy of N2 neck disease.

Adult↗
PubMed2002

Organotin and Irgarol-1051 contamination in Singapore coastal waters.

The seas surrounding Singapore are principally utilized by the shipping industry but are now also increasingly used for a variety of other purposes, including desalination for supplies of drinking water and intensive aquaculture of food fish. While stringent environmental pollution standards are in place for industrial effluents, there is currently no legislative control over pollution from anti-fouling paints in Singapore. In this study, the concentrations of toxic antifouling agents tributyltin (TBT), triphenyltin (TPhT) and Irgarol-1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine) were determined from seawater obtained from 26 locations along and off the coast of Singapore in October and November 2000. These compounds were isolated by liquid-liquid extraction derivatized under controlled microwave heating and quantified by gas chromatography-mass spectrometry. TBT concentrations in seawater ranged between 0.43 and 3.20 microg 1(-1) with a mean value of 1.40 +/- 0.60 micro 1(-1). The mean values of DBT and MBT were 1.07 +/- 0.80 microg 11(-1) and 0.34 +/- 0.50 microg 1(-1) respectively, while TPhT concentrations of up to 0.40 microg 1(-1) were found. Monophenyltin and diphenyltin were not detected in all samples analysed. Irgarol-1051 was found to be present at concentrations of between 3.02 microg 1(-1) and 4.20 microg 1(-1) in seawater with a mean value of 2.00 +/- 1.20 microg 1(-1).

Environmental Monitoring↗