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Biomedical subjects

S G Lee

Publications and source records attributed to S G Lee.

At least 19 recordsLinked to original sources
PubMed2003

Effect of dissolved oxygen concentration on the biofilm and in situ analysis by fluorescence in situ hybridization (FISH) and microelectrodes.

A better understanding of microbiology and ecology of nitrifying bacteria in inner biofilms is an important part of improving process performance and control. Microelectrodes and fluorescent in situ hybridization (FISH) in biofilm research have been used to investigate the spatial distributions of various microbial activities in biofilms and have led to new experimental findings as well as modifications of the homogeneous assumptions in the biofilm kinetic models. The objective of this study is to try the combination of two methods, both FISH and microelectrode measurements, and to provide reliable and in situ information on nitrifying bacterial activity in biofilms. The characteristics of biofilm developed on tygon slides were different according to the change of dissolved oxygen (DO). When the DO increased from 2 to 10 mg DO/L, the rate of the biofilm thickness increased and its dry density changed from 50-70 to 25-90 mg/cm3. Ammonia oxidizing bacteria were not uniformly distributed in biofilm, and were found at the deeper layer where oxygen is depleted, they were detected primarily in the upper and middle layers of the biofilm.

Bacteria↗
PubMed2002

Host cell proteins binding to the encapsidation signal epsilon in hepatitis B virus RNA.

The highly conserved encapsidation signal (epsilon) of hepatitis B viral (HBV) pregenomic RNA has been reported as an essential component for encapsidation and protein priming of HBV polymerase. Here, we report that two HBV epsilon RNA-binding host proteins (80 and 43 kDa) and a copurifying protein (100 kDa) were purified and characterized by the combined methods of UV cross-linking analysis with the epsilon RNA and column chromatography. Amino-terminal microsequencing showed that 80- and 43-kDa proteins were identified as the heterodimeric nuclear factor of activated T cells (NF90/NF45) and 100 kDa as a molecular chaperone, the GRP94. The heterodimeric factor interacted preferentially with the upper-bulge region of HBV epsilon RNA helping the HBV polymerase bind the lower-bulge region. Using in vitro protein priming analysis, the initial oligonucleotide of the protein-priming product was deduced as 5'-GAAC-3', which is the complementary sequence of both regions of DR1 and epsilon in the pregenomic RNA. Previously, we also proposed that the GRP94 was associated with HBV polymerase in the human liver cell HepG2. These results suggest that the heterodimeric factor plays an important role in the priming activity of HBV polymerase.

Amino Acid Sequence↗
PubMed2002

Adult-to-adult living donor liver transplantation at the Asan Medical Center, Korea.

Between February 1997 and December 2001, 311 adult-to-adult living donor liver transplants (A-A LDLTs) were performed at the Asan Medical Center for patients above 20 years of age. Indications for A-A LDLT were: chronic hepatitis B (203), chronic hepatitis C (5), hepatocellular carcinoma (64), alcoholic cirrhosis (9), cryptogenic cirrhosis (4), secondary biliary cirrhosis (5), primary biliary cirrhosis (1), Wilson' s disease (2), autoimmune hepatitis (1), hepatic tuberculosis (1), cholangiocarcinoma (1), fulminant hepatic failure (14) and primary non-function of cadaveric liver graft (1). Of 311 A-A LDLTs, 36 were of medical high urgency, 20 were for acute and subacute hepatic failure, 15 were for hepato-renal syndrome and 1 was for primary non-function. Recipient age ranged from 27 to 64 years. Donor age ranged from 16 to 62 years. There was no donor mortality. Implanted liver grafts were categorized into seven types: 175 modified right lobe (MRL), 70 left lobe, 32 right lobe, 20 dual grafts, 10 left lobe plus caudate lobe, three extended right lobe and one posterior segment. In MRL, the tributaries of the middle hepatic vein were reconstructed by interpositioning a vein graft. Indication for dual graft implantation was the same as single graft A-A LDLT, and four of 20 were emergency cases. Of 20 dual grafts, 14 received two left lobes, four received a left lobe and a lateral segment, one received a right lobe and a left lobe and one received a lateral segment and a posterior segment. Graft volume ranged from 28% to 83% of the standard liver volume of the recipients. There were 33 (10.6%) in-hospital mortalities (< 4 months) among the 310 patients after 311 A-A LDLTs. Of the 36 patients receiving emergency transplants, 31 survived. These encouraging results justify the expansion of A-A LDLT in coping with increasing demands, even in urgent situations. We have aimed to introduce the establishment of the efficacy of A-A LDLT in various end-stage chronic and acute liver diseases, as well as new technical advances to overcome small graft-size syndrome by using dual-graft implantation and MRL, both of which were first developed in our department.

Adult↗
PubMed2002

Interdependent effect of angiotensin-converting enzyme and platelet-activating factor acetylhydrolase gene polymorphisms on the progression of immunoglobulin A nephropathy.

In order to investigate the interdependent action of the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) gene and polymorphism in exon 11 (C1136-->T; Ala379Val) of the platelet-activating factor acetylhydrolase (PAF-AH) gene, which encodes a functional antagonist of PAF, on the progression of immunoglobulin A (IgA) nephropathy, we analysed both polymorphisms in patients with primary IgA nephropathy, who were followed-up for longer than 3 years. During the follow-up (87.3 +/- 50.0 months), the disease progressed in 38 of the 191 patients (19.9%). The D allele of the ACE gene in the absence of the T allele of the PAF-AH gene did not affect the prognosis [odds ratio (OR), 3.6; 95% confidence interval (CI), 0.8-16.4] and neither did the T allele in the absence of the D allele (OR, 3.0; 95% CI, 0.4-24.2). However, the presence of both was a significant prognostic factor (OR, 6.6; 95% CI, 1.4-31.3). After adjusting for other risk factors, the presence of both proved to be an independent risk factor (OR, 4.5; 95% CI, 1.6-12.7). These results suggest that the interdependent effects of ACE and PAF-AH polymorphisms on the progression of IgA nephropathy might be more important than the effect of the individual polymorphisms.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2002

Geobacillus toebii sp. nov., a novel thermophilic bacterium isolated from hay compost.

A thermophilic, spore-forming rod isolated from hay compost in Korea was subjected to a taxonomic study. The micro-organism, designated strain SK-1(T), was identified as being aerobic, Gram-positive, motile and rod-shaped. Growth of the isolate was observed at 45-70 degrees C (optimum 60 degrees C) and pH 6.0-9.0 (optimum pH 7.5). The G+C content of the genomic DNA was 43.9 mol%. Chemotaxonomic characteristics of the isolate included the presence of mesodiaminopimelic acid in the cell wall and iso-C15:0 and iso-C17:0 as the major cellular fatty acids. The predominant isoprenoid quinone was MK-7. The chemotaxonomic characteristics of strain SK-1(T) were the same as those of the genus Geobacillus. Phylogenetic analysis based on 16S rDNA sequences showed that strain SK-1(T) is most closely related to Geobacillus thermoglucosidasius. However, the phenotypic properties of strain SK-1(T) were clearly different from those of G. thermoglucosidasius. The level of DNA-DNA relatedness between strain SK-1(T) and the type strain of G. thermoglucosidasius was 27%. On the basis of the phenotypic traits and molecular systematic data, strain SK-1(T) represents a novel species within the genus Geobacillus, for which the name Geobacillus toebii sp. nov. is proposed. The type strain is strain SK-1(T) (= KCTC 0306BP(T) - DSM 14590(T)).

Base Composition↗
PubMed2002

Peripheral arterial insufficiency associated with protein C deficiency.

Two patients with protein C deficiency who presented with peripheral arterial insufficiency were successfully managed. One patient was managed with bypass surgery for focal gangrene followed by full anticoagulation whilst the other patient was managed with full anticoagulation. Both patients showed characteristic arteriographic findings. Patients who present with peripheral arterial insufficiency demonstrating thrombotic occlusion of main peripheral artery without atherosclerosis and other risk factors should be evaluated for hypercoagulable states.

Adult↗
PubMed2001

Diaquabis(propane-1,2-diamine-N,N')nickel(II) bis(p-toluenesulfonate).

The crystal structure of the title compound, [Ni(C(3)H(10)N(2))(2)(H(2)O)(2)](C(7)H(7)O(3)S)(2) or [Ni(H(2)O)(2)[NH(2)CH(2)CH(NH(2))CH(3)](2)](CH(3)C(6)H(4)SO(3))(2), exhibits a layered structure in which the complex cations and the p-toluenesulfonate anions form alternating layers. The central Ni(II) atom of the cation resides on a crystallographic inversion centre and has a slightly distorted octahedral coordination composed of the water ligands bonding through oxygen in a trans arrangement and the N,N'-bidentate propanediamine ligands. The p-toluenesulfonate anions are arranged with the sulfonate groups turned alternately towards opposite sides of the layers. The structure of the layers is stabilized by a network of hydrogen bonds between the sulfonate O atoms, water molecules and the propanediamine N atoms.

Journal Article↗
PubMed2001

Transcriptional repression of the human p53 gene by cobalt chloride mimicking hypoxia.

The switch to an angiogenic phenotype is known to be a fundamental determinant of neoplastic growth and tumor progression. We herein report that the transcription of the human p53 gene was repressed by treatment with a hypoxia-mimicking concentration of cobalt chloride and alone by hypoxia-inducible factor 1alpha. Analyses of serial deletions, site-directed mutageneses and heterologous promoter systems showed that the site responsible for the repression by both factors was the E-box element in the promoter of the p53 gene. These results alongside previous data suggest that the loss of p53 including the transcriptional repression may play an important role in the angiogenic switch during tumorigenesis.

Cell Hypoxia↗
PubMed2001

Gene structure of the human DDX3 and chromosome mapping of its related sequences.

The human DDX3 gene (GenBank accession No. U50553) is the human homologue of the mouse Ddx3 gene and is a member of the gene family that contains DEAD motifs. Previously, we mapped the gene to the Xp11.3-11.23. In this report, we describe the structural organization of the human DDX3 gene. It consisted of 17 exons that span approximately 16 kb. An Alu element was present in the intron 13. Its organization was the same as that of the human DBY gene, a closely related sequence present on the Y chromosome. We also identified two processed pseudogenes (DDX3) with a sequence that is highly homologous to those of DDX3 cDNAs, but contain a translation termination codon within its open-reading frame. Pseudogenes are mapped on human chromosomes 4 and X, respectively. In this paper, we discuss the relationships between DDX3 and its related sequences that have been isolated.

Amino Acid Sequence↗
PubMed2001

Characterization of publicly available SNPs in the Korean population.

Single-nucleotide polymorphisms (SNPs) are the most abundant form of genetic variations and have a great potential for mapping studies of complex genetic traits. Currently a great deal of effort is invested in the identification of SNPs, and a large volume of data is already available through public databases (NCBI, NCI, WICGR, HGBASE). For an association mapping study, SNP allele frequencies in the population are critical. As an initial step toward construction of an SNP database of the Korean population, we have determined the allele frequencies of 300 cSNPs selected from the public database in 24 individuals. Among the tested markers, approximately 23% did not show polymorphism in the population. The results suggest that the ethnic and population based differences should be considered in the selection of SNPs for the study of complex diseases with association mapping methods.

Alleles↗
PubMed2001

Isolation and characterization of a Bacillus thuringiensis ssp. kurstaki strain toxic to Spodoptera exigua and Culex pipiens.

A strain of Bacillus thuringiensis with dual toxicity was isolated from Korean soil samples and named K2. K2 was determined as ssp. kurstaki (H3a3b3c) by serological test and produced bipyramidal-shaped parasporal inclusions. The plasmid and protein profiles of B. thuringiensis K2 were different from those of the reference strain, ssp. kurstaki HD-1. To verify gene type of B. thuringiensis K2, PCR analysis with specific cry gene primers was performed. The result showed that B. thuringiensis K2 had cry1Aa, cry1Ab, cry1C, and cry1D type genes, whereas ssp. kurstaki HD-1 had cry1Aa, cry1Ab, cry1Ac, and cry2 type genes. In addition, B. thuringiensis K2 had high toxicity against Spodoptera exigua and Culex pipiens, whereas B. thuringiensis ssp. kurstaki HD-1 does not have high toxicity against these two insect species.

Animals↗
PubMed2001

Displacement of microcalcifications during stereotactic 11-gauge directional vacuum-assisted biopsy with marking clip placement: case report.

A 53-year-old woman with right breast microcalcifications of intermediate concern underwent stereotactic directional vacuum-assisted biopsy with marking clip placement. Postbiopsy mammograms showed displacement of a few of the targeted microcalcifications adjacent to misplaced marker clips. Mammography following stereotactic breast biopsy is important to document the location and number of residual calcifications and to determine the adequacy and location of clip placement.

Biopsy↗
PubMed2001

Neuropathic arthropathy of the elbow. A report of five cases.

BACKGROUND: Neuropathic arthropathy of the elbow is rare and characterized by a painless but unstable articulation. The functional capacity of patients with this condition has not been reviewed in detail. METHODS: Five male patients, with an average age of fifty-one years, were treated for neuropathic arthropathy of the elbow. The underlying conditions associated with the arthropathy included syringomyelia, insulin-dependent diabetes mellitus, end-stage renal failure, and two cases of polyneuropathy of unknown cause. Four patients sought medical attention after a specific traumatic event. Peripheral sensory and motor dysfunction was present in each patient. Radiographs of the elbow revealed dislocation, fracture fragmentation, and heterotopic ossification. Our management of the neuropathic elbows centered on maintenance of a functional arc of motion through physical therapy aimed at regaining muscle strength and the use of orthoses for support. Operative treatment was performed for an associated ulnar or radial nerve compression syndrome in three patients, and an open reduction and internal fixation of an unstable proximal ulnar nonunion associated with loose implants was performed in one. RESULTS: The patients were followed for an average of nineteen months, with a range of twelve to thirty-six months. All patients had a pain-free elbow with a functional range of motion at the most recent follow-up examination, and none wished to have further treatment. The operatively treated ulnar nonunion united successfully. All three patients treated surgically for an associated nerve compression syndrome had recovery of nerve function. CONCLUSION: In the face of instability and gross distortion of the joint, the patients in this series demonstrated remarkably good function.

Adult↗
PubMed2001

Effect of heavy metals (Cu, Pb, and Ni) on the compositions of EPS in biofilms.

A series of batch adsorption tests to estimate the biofilm capacity for removal of the heavy metals (Cu, Pb, and Ni) in wastewater were carried out. The metal sorption results were fitted to the Freundlich isotherm model to compare their sorption capacity. The change of the composition of EPSs (extracellular polymeric substances) was simultaneously represented by the ratio of carbohydrate to protein (C/P) when the biofilm was exposed to the heavy metals. EPS composed of slime loosely bound to the cell and capsular materials was extracted by the four general extraction methods including regular centrifugation, regular centrifugation with formaldehyde, EDTA extraction and steam extraction. Although the various extraction methods showed different results, C/P ratio of biofilm exposed to copper and lead metal ions was generally lower than that of control.

Adsorption↗
PubMed2001

Health development experience in North and South Korea.

The purpose of this study is to compare the difference in health status between South Koreans and North Koreans and to identify factors responsible for the remarkable improvements in the health status of South Koreans. In order to examine the causes of the difference in health level, the health indices and their determinants of two Koreas were analyzed in time order. As of the year 2000, the average life expectancy at birth is 71.0 years for men and 78.6 years for women in South Korea, which is longer than that of North Korea by 8.1 for men and 11.2 for women. Infant mortality rate in 1998 was 9.0 per 1,000 live births in South Korea and 54.0 in North Korea. Since being liberated from Japanese ruling in 1945, South Korea has achieved remarkable economic growth under democracy and a market economy system. On the other hand, North Korea has maintained a socialistic system. North Korea has suffered from economic crisis since the 1990s. From this point it could be said that economic status is the major factor for the differences in health level between the two Koreas. Economic status not only directly influences health level but also indirectly affects it through influences on nutrition, hygiene, health resources, and other intervening factors. The South Korean government has concentrated its limited resources on public health activities such as tuberculosis control, family planning (FP), and maternal and child health (MCH) programmes whereas the private sector has taken charge of constructing the health delivery system including health facilities and human resources. In order to solve the problem, which might occur in the private-oriented medical care system, the South Korean government has introduced the national health insurance programme and enforced regulation policies. Many developing countries which are suffering from poverty and disease, can learn from the experience of Korea that had suffered from similar problems up to the early 1970s.

Delivery of Health Care↗
PubMed2000

Interaction of human Ku70 with TRF2.

Ku, a heterodimer of 70- and 80-kDa subunits, plays a general role in the metabolism of DNA ends in eukaryotic cells, including double-strand DNA break repair, V(D)J recombination, and maintenance of telomeres. We have utilized the yeast two-hybrid system to identify Ku70-interacting proteins other than Ku80. Two reactive clones were found to encode the dimerization domain of TRF2, a mammalian telomeric protein that binds to duplex TTAGGG repeats at chromosome ends. This interaction was confirmed using bacterial fusion proteins and co-immunoprecipitations from eukaryotic cells overexpressing TRF2. The transfected TFR2 colocalized with Ku70.

Animals↗