Biomedical subjects

H Kim

Publications and source records attributed to H Kim.

At least 91 records · Page 5Linked to original sources

PubMed2003

FISH analysis for chromosomes 13, 16, 18, 21, 22, X and Y in all blastomeres of IVF pre-embryos from 144 randomly selected donated human oocytes and impact on pre-embryo morphology.

BACKGROUND: The data are compiled from two multicentre, prospectively randomized studies on the effect of follicular fluid meiosis-activating sterol (FF-MAS) on human oocytes. The donated oocytes were exposed either to test doses of FF-MAS or to control solutions. The data from the control groups are presented with chromosomal status of the embryos correlated to embryo morphology. METHODS: The study includes 144 randomly selected donated human oocytes. The nucleus from each blastomere was fixed separately and fluorescence in-situ hybridization (FISH) using seven probes (13, 16, 18, 21, 22, X and Y) was performed. RESULTS: Analysis of 103 pre-embryos containing 479 blastomeres resulted in 424 blastomeres with clear FISH signals. Of these blastomeres, 55% were normal diploid and 45% were abnormal. At a pre-embryonic level, 53% were classified as normal containing >or=50% normal blastomeres while 31% of the pre-embryos were classified as uniformly normal. Abnormality rate was significantly increased in the pre-embryos with unevenly sized blastomeres and with increasing degree of fragmentation at 68 h after fertilization. Applying criteria for good embryo quality significantly increased the rate of chromosomally normal pre-embryos from 53 to 75%. CONCLUSIONS: The data demonstrate the high degree of genetic heterogeneity in a randomly selected pool of donated pre-embryos from an IVF programme. Further, we found that uniformity of blastomere size, degree of fragmentation and cleavage kinetics reflect the cytogenetic status of the pre-embryo and are therefore important in the selection of pre-embryos.

Blastomeres↗

PubMed2003

Genetic markers and their application in poultry breeding.

The current chicken genetic map contains at least 1,965 loci within 50 linkage groups, and it covers about 4,000 cM. About 235 of these loci have homology with known human or mammalian genes. The remaining loci are anonymous molecular DNA markers, including microsatellites, amplified fragment length polymorphism (AFLP), randomly amplified polymorphic DNA (RAPD), CR1 elements, and others. A third generation genetic map for human uses single nucleotide polymorphisms (SNP), which have allowed the mapping of complex traits by linkage disequilibrium. One advantage of SNP is that they are usually linked to the gene of interest, and association of the SNP with traits of economic importance can be analyzed using candidate gene approaches. With the tremendous advancements in characterizing chicken expressed sequence tags (EST), the identification of genetic polymorphisms such as SNP in chicken genes has become a reality. Our laboratory has undertaken an in silico analysis of the chicken EST at the University of Delaware by using a Phred/Phrap/Polyphred/Consed pipeline to identify candidate chicken SNP. Initial scanning of 23,427 chicken EST identified a total of 1,209 candidate SNP, with at least 182 non-synonymous SNP that result in an amino acid change observed. Validation of these candidate chicken SNP is ongoing. Placement of the SNP on the chicken genetic map will enhance marker density, thus allowing for mapping of complex traits through linkage analysis and linkage disequilibrium. Application of SNP to identify disease resistance genes in chickens is of special interest to our laboratory, especially in regards to Marek's disease and coccidiosis.

Animal Husbandry↗

PubMed2003

Quantitative polymerase chain reaction assay for serum hepatitis B virus DNA as a predictive factor for post-treatment relapse after lamivudine induced hepatitis B e antigen loss or seroconversion.

BACKGROUND AND AIMS: Lamivudine induces favourable virological and biochemical responses but post-treatment relapses are frequent, even in patients with hepatitis B e antigen (HBeAg) loss or seroconversion. The aim of this study was to determine whether extended lamivudine therapy for up to 12 months after HBeAg loss/seroconversion could decrease the risk of post-treatment virological relapse. In addition, we monitored serum hepatitis B virus (HBV) DNA levels using a quantitative polymerase chain reaction (PCR) assay during extended lamivudine therapy and analysed predictive factors for post-treatment relapse. PATIENTS AND METHODS: A total of 49 patients who exhibited HBeAg loss/seroconversion during lamivudine therapy received extended lamivudine therapy for six months (group 1, n=23) or 12 months (group 2, n=26) after HBeAg loss/seroconversion. Serum HBV DNA levels were quantified by a PCR based assay at the time of HBeAg loss/seroconversion, and at cessation of therapy. RESULTS: Post-treatment virological relapse rates at two years were 59% in group 1 and 50% in group 2. Age, time interval to HBeAg loss/seroconversion, and serum HBV DNA levels at the time of cessation of therapy were independent predictive factors for post-treatment relapse. The post-treatment relapse rate was 37% at two years in patients with serum HBV DNA levels of <200 copies/ml but 73% in those with > or =10(3) copies/ml. CONCLUSIONS: Extended lamivudine therapy for up to 12 months did not decrease the rate of post-treatment virological relapse, and monitoring of serum HBV DNA by a quantitative PCR method was helpful in predicting post-treatment relapse.

Adult↗

PubMed2003

Association of the CD14 gene -159C polymorphism with progression of IgA nephropathy.

The risk factors associated with the progression of IgA nephropathy (IgAN), the most common form of glomerulonephritis, are unclear. It has been suggested that CD14 signalling in response to various microbes affects the natural history of chronic inflammatory conditions. It has been hypothesised that variants in the promoter region of the CD14 gene might alter the expression of CD14, and this in turn could influence the progressive nature of IgAN. PCR-RFLP was used to determine the polymorphism at the -159 site (T to C). The distribution of the CD14/-159 polymorphism was no different in patients with IgAN (n=216) compared to 171 healthy controls. After follow up for 86 months, it was found that an excess of the C genotype occurred in patients with progressive disease (p=0.03) and the risk of disease progression increased as the number of C alleles increased (p for trend = 0.002). The hazard ratio for progression in the patients with the CC genotype was 3.2 (p=0.025) compared with the patients possessing the TT genotype. After LPS stimulation, sCD14 was released more abundantly from the PBMCs of the TT subjects than from that of the CC subjects (p=0.006), even though mCD14 expression level was no different. In addition, the TT subjects released less IL-6 than the CC subjects after stimulation (p=0.0003). These results suggest that the CD14/-159 polymorphism is an important marker for the progression of IgAN and may modulate the level of the inflammatory responses.

Adult↗

PubMed2003

Modulation of immune responses by treadmill exercise in Sprague-Dawley rats.

AIM: The duration-dependence of the effect of forced treadmill exercise on the immune system is a subject of ongoing research. In this study, the effect of forced treadmill exercise on immune responses was investigated by evaluating the lymphocyte subset fractions in the peripheral blood and spleen of Sprague-Dawley rats. METHODS EXPERIMENTAL DESIGN: Comparative investigation over 8 weeks. SETTING: Experimental animal laboratory. PARTICIPANTS: Male Sprague-Dawley rats 5 weeks of age, weighing 150+/-10 g. INTERVENTIONS: Animals were randomly assigned to one of the 4 following groups: the control group, the 1-week-exercise group, the 4-week-exercise group, and the 8-week-exercise group. MEASURES: Lymphocyte subset fractions, including those for T, B, CD4+, and CD8+ cells and the T/B and CD4+/CD8+ ratios in the peripheral blood and spleen were measured via flow cytometric analysis after treadmill exercise. RESULTS: The T cell and CD4+ cell fractions in both the peripheral blood and spleen were increased significantly after 8 weeks of treadmill exercise, but the B cell and CD8+ cell fractions did not change significantly. CONCLUSION: From the results of the present study, it is suggested that a period of one week is insufficient to eliminate the effects of exercise-induced stress, that 4 weeks are needed to return to the control state, and that at least 8 weeks are needed in order for exercise of moderate intensity to have a positive effect on the immune system.

Adaptation, Physiological↗

PubMed2003

Performance of a hybrid SBR with fixed bed and suspended growth.

A hybrid SBR system combined with fixed bed (media) and suspended growth zones was developed to improve both nitrogen and phosphorus removal. About 27% of the tank volume was filled with clay media to make a fixed bed in this system, and additional air was applied under the bed to wash the microbes from the media during the oxic stage to prevent the bed from clogging. This hybrid SBR system could eliminate the backwashing requirement for SBBR (sequencing batch biofilm reactor). This system showed a stable nitrification even at low temperature and shock load conditions. The specific reaction rates indicated the fixed bed zone had higher microbial activities for nitrification and denitrification, while the suspended growth zone had higher microbial activities for phosphorus release and uptake. In addition, the use of external sludge storage also increased both phosphorus and nitrogen removal. The effluent COD, nitrogen and phosphorus concentrations were respectively less than 15, 10.5 and 0.6 mg/L with weak sewage of 230 mg/L COD, 35 mg/L TKN and 5.3 mg/L TP.

Bioreactors↗

PubMed2002

The effect of a disrupted yhjQ gene on cellular morphology and cell growth in Escherichia coli.

The 5' upstream region of the cellulose synthase operon ( bcs operon) has been isolated by cloning from Escherichia coli. A gene encoding YhjQ is located 1.0 kb upstream of the bcs operon in E. coli. The function of YhjQ remains unknown. Insertional inactivation of the yhjQ gene causes abnormal cell division, resulting in incomplete partition of the chromosome and filamentous cells of various sizes. These results suggest that the product of yhjQ may affect normal doubling and cellular morphology.

Cell Cycle↗

PubMed2002

Bandgap modulation of carbon nanotubes by encapsulated metallofullerenes.

Motivated by the technical and economic difficulties in further miniaturizing silicon-based transistors with the present fabrication technologies, there is a strong effort to develop alternative electronic devices, based, for example, on single molecules. Recently, carbon nanotubes have been successfully used for nanometre-sized devices such as diodes, transistors, and random access memory cells. Such nanotube devices are usually very long compared to silicon-based transistors. Here we report a method for dividing a semiconductor nanotube into multiple quantum dots with lengths of about 10nm by inserting Gd@C82 endohedral fullerenes. The spatial modulation of the nanotube electronic bandgap is observed with a low-temperature scanning tunnelling microscope. We find that a bandgap of approximately 0.5eV is narrowed down to approximately 0.1eV at sites where endohedral metallofullerenes are inserted. This change in bandgap can be explained by local elastic strain and charge transfer at metallofullerene sites. This technique for fabricating an array of quantum dots could be used for nano-electronics and nano-optoelectronics.

Journal Article↗

PubMed2002

Risk period for developing osteonecrosis of the femoral head in patients on steroid treatment.

Patients who require long-term steroid use are at risk for the development of osteonecrosis. However, the risk period for developing osteonecrosis of the femoral head has not yet been defined. The authors attempted to determine the onset of osteonecrosis of the femoral head following steroid treatment. Medical record data of patients with steroid-related osteonecrosis of the femoral head from four university hospitals were reviewed. Information was collected regarding the duration and dose of steroid use for patients who were diagnosed at the early stage by magnetic resonance imaging (MRI) without positive findings on plain radiographs (Association Research Circulation Osseous stage I osteonecrosis). Twenty-two patients were diagnosed at Association Research Circulation Osseous stage I. There were eight male and 14 female patients ranging in age from 17 to 60 years (mean 33). The total dose of steroid, which was used until the time of detection of osteonecrosis by MRI, ranged from 1800 to 15 505 mg prednisolone or its equivalent (mean 5928 mg). The period from the start of steroid treatment to the diagnosis by MRI ranged from 1 month to 16 months (mean 5.3 months). Twenty-one of 22 patients were diagnosed within 12 months of the initiation of steroid treatment. The duration of steroid treatment within this period ranged from 1 month to 12 months (mean 4.5 months). There may be a risk period of 12 months for developing femoral head osteonecrosis in patients receiving long-term steroid treatment. Close observation and more aggressive screening are recommended within the first year of long-term steroid treatment to prevent advanced osteonecrosis of the femoral head.

Adolescent↗

PubMed2002

Free radical scavenging effect of Diospyros kaki, Laminaria japonica and Undaria pinnatifida.

Diospyros kaki folium, Laminaria japonica thallus and Undaria pinnatifida thallus have been used traditionally in Korea to promote maternal health. The scavenging activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals of the methanol extracts of these plants were investigated. The extract of D. kaki was found to be the most potent, with an IC(50) value of 0.11 mg/ml.

Biphenyl Compounds↗

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

The plasma levels of interleukin-12 in schizophrenia, major depression, and bipolar mania: effects of psychotropic drugs.

Interleukin-12 (IL-12) plays a key role in promoting T helper 1 (Th1) responses and subsequent cell-mediated immunity. Given the role of cytokines in the pathogenesis of psychiatric disorders, the dysregulation of IL-12 in these illnesses would be expected. We measured the plasma levels of IL-12 in 102 psychiatric patients (43 schizophrenia, 34 major depression and 25 bipolar disorder) and 85 normal controls. In addition, IL-12 levels of the patients were measured after an 8-week treatment to assess whether the levels were affected by medication. The IL-12 levels of the patient group with major depression were significantly higher than that of the control group, whereas no differences were found among the other groups. IL-12 values of the three patient groups decreased significantly after 8 weeks of treatment. These findings support the hypothesis that activation of the inflammatory response system and in particular of Th-1-like cells, is involved in the pathophysiology of major depression and that repeated administration of antidepressive and antipsychotic drugs may suppress IL-12 plasma concentrations in psychiatric patients.

Adolescent↗

PubMed2002

Nonconvulsive status epilepticus presenting as a subacute progressive aphasia.

We report a 62-year-old man with non-convulsive status epilepticus (NCSE) presenting as a progressive aphasia that developed insidiously over 5 weeks. On video-EEG monitoring, aggravation of the aphasia coincided with occurrence of seizure activities arising from the left fronto-temporal area. Brain MRI was noncontributory but a fluorodeoxyglucose-PET scan revealed a hypometabolism in the left anterior temporal area. Following anticonvulsant treatment, aphasia recovered gradually over several weeks despite prompt resolution of epileptic discharges on EEG. Our patient's findings, gradual onset of isolated aphasia with gradual resolution after initiation of treatment, may differ from previously reported cases with aphasic status epilepticus because their aphasia showed abrupt onset and rapid resolution with anticonvulsant medication.

Brain↗

PubMed2002

Biofiltration of ammonia gas with sponge cubes coated with mixtures of activated carbon and zeolite.

Removal of ammonia gas was investigated using a biofilter system packed with small cubes of polyurethane sponge that were coated with a powder mixture of activated carbon and natural zeolite. Experimental tests and measurements include removal efficiency, pH, metabolic products of ammonia and kinetic analysis. A removal efficiency over 90% can be obtained with ammonia concentrations below 150 ppm and at contact times above 23 sec.The ammonia adsorbing power of the present biocarrier can protect the biofilter system from a high ammonia shock loading in the feed. The maximum removal rate, Vm, obtained from the kinetic analysis is 8.47 g N (kg carrier)(-1) day(-1) and the saturation constant Ks is 50.36 ppm. Nitrite is produced dominantly during the entire experiments. The cell number of nitrifying bacteria is 1.58 x 10( cell (g carrier)(-1). The present synthetic bio-carrier is considered to be one of the best among bio-carriers that have been used for the biofiltration of ammonia.

Ammonia↗

PubMed2002

Genetic diversity at the major histocompatibility complex (B) and microsatellite loci in three commercial broiler pure lines.

Genetic diversity at the MHC and non-MHC loci was investigated in three commercial broiler chicken pure lines. The MHC class II and IV loci were evaluated in Southern hybridizations and molecular genotypes based on RFLP were interpreted from pedigreed families. Four MHC class II and eight class IV genotypes were identified in the broiler lines, and their frequencies differed among the lines. Line-specific MHC genotypes were identified. The observed heterozygosities (59 to 67%) suggest that the MHC loci are highly polymorphic in the broiler lines. At least 9% of the genetic variation at the MHC was due to line differences; the remainder reflected individual variations. To characterize non-MHC genes, 41 microsatellite loci located throughout the chicken genome were evaluated in the broiler lines. Genetic variation was also observed at the microsatellite loci for the broiler lines; the number of alleles at a single locus ranged from one to eight, and the average number of alleles per locus was 3.5, 2.8, and 3.1 for each of the lines, respectively. The observed heterozygosities for microsatellite loci ranged between 0 and 89% in the lines. Based on the fixation index (Fst), about 19% of the genetic variation at microsatellite loci was attributed to broiler line differences. Deviations from Hardy-Weinberg equilibrium were detected at both MHC and non-MHC loci. Possible explanations for these deviations include genetic selection by the primary broiler breeder or the presence of null alleles that were not identified by the typing procedures described in this report. This study contributes to our knowledge on the molecular characteristics and genetic structure of a commercial broiler chicken population. Analysis of MHC and non-MHC loci suggests that there is still sufficient genetic diversity in the broiler lines to continue the progress toward improved broiler chicken production.

Animals↗

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

Cytochrome P450 3A conjugation to ubiquitin in a process distinct from classical ubiquitination pathway.

We characterize a novel microsome system that forms high-molecular-mass (HMM) CYP3A, CYP2E1, and ubiquitin conjugates, but does not alter CYP4A or most other microsomal proteins. The formation of the HMM bands was observed in hepatic microsomes isolated from rats treated 1 week or more with high doses (50 mg/kg/day) of nicardipine, clotrimazole, or pregnenolone 16alpha-carbonitrile, but not microsomes from control, dexamethasone-, nifedipine-, or diltiazem-treated rats. Extensive washing of the microsomes to remove loosely attached proteins or cytosolic contaminants did not prevent the conjugation reaction. In contrast to prototypical ubiquitination pathways, this reaction did not require addition of ubiquitin, ATP, Mg(2+), or cytosol. Addition of cytosol did result in the degradation of the HMM CYP3A bands in a process that was not blocked by proteasome inhibitors. Immunoprecipitated CYP3A contained HMM ubiquitin. Even so, mass spectrometric analysis of tryptic peptides indicated that the HMM CYP3A was in molar excess to ubiquitin, suggesting that the formation of the HMM CYP3A may have resulted from conjugation to itself or a diffuse pool of ubiquitinated proteins already present in the microsomes. Addition of CYP3A substrates inhibited the formation of the HMM CYP3A and the cytosol-dependent degradation of HMM CYP3A. These results suggest that after extended periods of elevated CYP3A expression, microsomal factors are induced that catalyze the formation of HMM CYP3A conjugates that contain ubiquitin. This conjugation reaction, however, seems to be distinct from the classical ubiquitination pathway but may be related to the substrate-dependent stabilization of CYP3A observed in vivo.

Animals↗

PubMed2002

Use of RNA and genomic DNA references for inferred comparisons in DNA microarray analyses.

In most microarray assays, labeled cDNA molecules derived from reference and query RNA samples are co-hybridized to probes arrayed on a glass surface. Gene expression profiles are then calculated for each gene based on the relative hybridization intensities measured between the two samples. The most commonly used reference samples are typically isolates from a single representative RNA source (RNA-0) or pooled mixtures of RNA derived from a plurality of sources (RNA-p). Genomic DNA offers an alternative reference nucleic acid with a number of potential advantages, including stability, reproducibility, and a potentially uniform representation of all genes, as each unique gene should have equal representation in a haploid genome. Using hydrogen peroxide-treated Arabidopsis thaliana plants as a model, we evaluated genomic DNA and RNA-p as reference samples and compared expression levels inferred through the reference relative to unexposed plants with expression levels measured directly using an RNA-0 reference. Our analysis demonstrates that while genomic DNA can serve as a reasonable reference source for microarray assays, a much greater correlation with direct measurements can be achieved using an RNA-based reference sample.

Arabidopsis↗