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Biomedical subjects

S Kim

Publications and source records attributed to S Kim.

At least 109 records · Page 6Linked to original sources
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

No association of the TGF-beta1 gene polymorphisms with the renal progression in autosomal dominant polycystic kidney disease (ADPKD) patients.

BACKGROUND: Two genetic loci, PKD I and PKD2, have been identified as being responsible for ADPKD, and PKD1 is known to be associated with a poor prognosis. However, the presence of an intrafamilial study clinical diversity suggests that there are disease-modifying loci. Because the mechanism ofthe renal failure in ADPKD includes a cystic growth and tubulointerstitial atrophy and fibrosis, we studied the associations between 2 polymorphisms in the TGF-beta1 gene, which are known to be associated with chronic tubulointerstitial inflammation, and ADPKD progression in Korean patients. PATIENTS AND METHODS: One hundred and twenty-five individuals who had ADPKD and 47 normal control subjects were genotyped by PCR-RFLP, the T869C (Leu10Pro) variant of TGF-beta gene leader sequence was discriminated with MspA1I and the G915C (Arg25Pro) variants with Bg1I. Statistical significances were determined using the Chi-square test. RESULTS: The distribution of the alleles for the TGF beta1 Leu10Pro polymorphism in ADPKD was: T 54%, C 46%, which was similar to the Korean (56: 44, p = 0.887) and Western controls (65: 35). In addition, no differences were found between the ESRD and the non-ESRD groups (p = 0.888) or the early hypertension and the normotension groups (p = 0.249). The distribution of alleles for the TGF beta1 Arg25Pro polymorphism showed only the GG type which was different from the Western population controls (G:C = 90:10, p = 0.000). CONCLUSIONS: Our results suggest that the polymorphism at Arg25Pro of TGF-beta1 in the Korean population has an allele distribution different from that ofthe Western population and that the polymorphism at Leu10Pro of TGF-beta1 has no association with the renal progression in Korean ADPKD patients.

Adult↗
PubMed2003

Proteolytic enzyme conjugated to SC-glucan as an enzymatic transdermal drug penetration enhancer.

The objective of this study was to investigate the effect of papain, a proteolytic enzyme, on the percutaneous absorption of drugs. To guarantee the enzyme stability during the skin penetration, papain was modified by the conjugation to SC-glucan. The enhancing activity of drug penetration was evaluated using antipyrine and indomethacin as hydrophilic and hydrophobic model drugs, respectively. The SC-glucan-papain conjugate was found to be very effective for facilitating the percutaneous absorption of antipyrine. Microscopic observations showed that the thickness of stratum corneum and viable epidermis was increased by the treatment of the SC-glucan-papain conjugate. Moreover, it induced phase separation, lacuna formation, and lamellar disruption within the stratum corneum interstices. These structural changes by the SC-glucan-papain conjugate are likely to be induced from hydrolysis of extensive crosslinking of corneocyte envelopes and intracellular proteins. However, the SC-glucan-papain conjugate showed no skin irritation according to the Draize test, which may be due to the difficulty of the SC-glucan-papain conjugate in penetrating into the skin.

Administration, Cutaneous↗
PubMed2003

Age-related change in serum concentrations of testosterone in middle-aged Korean men.

The objective of this study was to determine whether testosterone and sex hormone binding globulin (SHBG) levels are different between healthy men and men with chronic illness, and to evaluate the age-related changes of testosterone and SHBG in healthy men in Korea. enrollment took place between January 2000 and December 2001 at Pundang CHA General Hospital in Korea. All men who came for male climacteric and geriatric health screening examinations were eligible. Of the 762 men recruited, 136 men had at least one present or previous medical illness and 626 men were healthy. Higher serum concentrations of total testosterone (5.31 +/- 1.88 ng/ml vs. 4.96 +/- 1.43 ng/ml; p < 0.05), free androgen index (16.60 +/- 7.36 vs. 14.57 +/- 5.55; p < 0.01) and calculated bioavailable testosterone (8.88 +/- 3.52 nmol/l vs. 7.91 +/- 2.52 nmol/l; p < 0.01) were demonstrated in the healthy compared with the disease group. Total testosterone declined at a rate of 0.2% per year, SHBG increased by 1.74% per year, calculated bioavailable testosterone declined by 0.8% per year, and free androgen index declined by 1.15% per year in healthy subjects aged between 40 and 70. The above results seem to be consistent with previous Western studies, showing higher concentrations of testosterone in healthy men, that decline with increasing age.

Adult↗
PubMed2003

Gas analysis reveals novel aerobic deammonification in thermophilic aerobic digestion.

A laboratory-scale thermophilic aerobic digester was operated with piggery wastewater. The operating temperature varied from 50-70 degrees C. It has been found that excessive nitrogen removal occurred in the laboratory-scale thermophilic system at various HRTs. Nitrite and nitrate were not observed in the effluent. Gas measurement reveals the presence of significant amount of N2O along with NH3 gas. The rational production of N2O gas in accordance with temperature and HRT suggests that biologically mediated deammonification processes significantly contribute to the N removal. Although further microbiological investigation is required to clarify the exact nitrogen removal mechanism, the large production of N2O gas seems to be a result of the existence of a rapid growing heterotrophic deammonification process in the thermophilic system.

Agriculture↗
PubMed2003

The evaluation of a density current experiment as a verification tool of a secondary clarifier model.

The prediction of the spatial and temporal flow regime is important for the efficient design and operation of the settling tank. The impact of the gravity current has been investigated by the temperature difference or artificial glass particles. This experimental study is designed to obtain the steady state of stratified flow with the consideration of the heavy density flow. Two different approaches were performed at lab scale considering the hydraulic similarity. One is the investigation of a heavy density current of saline water intrusion. The characteristics of the internal hydraulics are monitored using Particle Image Velocimetry (PIV). As a result of the saline intrusion, the internal flow established a continual density stratification of 3-layers in steady state. The other is the movement of activated sludge from a sewage treatment plant. The video image is captured to analyze the behavior of activated sludge in the settling tank. The experiments with various inlet baffle conditions suggest that the hydraulic characteristics of the two experiments are significantly different. As the distance between the baffle and inlet point was decreased, significant strength of saline density currents in the bottom layer was observed. However, the strength of the velocity in the bottom density currents appeared to be the opposite in the case of the activated sludge. The reason for the slower density current in the bottom layer is associated with the compressibility of activated sludge characteristics.

Particle Size↗
PubMed2002

Gamma spectra resulting from the annihilation of positrons with electrons in a single core level.

The first gamma spectra associated with the annihilation of positrons with individual core levels (Cu 3p and Ag 4p) are presented. The spectra were obtained by measuring the energy of gamma rays time coincident with Auger electrons emitted as a result of positrons annihilating with a selected core level. Relativistic calculations show good agreement with experiment over a limited range of momenta. However, statistically significant differences indicate that the measurements can provide an impetus to new calculations of many body effects in positron-core electrons annihilation.

Journal Article↗
PubMed2002

Geometric fractal growth model for scale-free networks.

We introduce a deterministic model for scale-free networks, whose degree distribution follows a power law with the exponent gamma. At each time step, each vertex generates its offspring, whose number is proportional to the degree of that vertex with proportionality constant m-1 (m>1). We consider the two cases: First, each offspring is connected to its parent vertex only, forming a tree structure. Second, it is connected to both its parent and grandparent vertices, forming a loop structure. We find that both models exhibit power-law behaviors in their degree distributions with the exponent gamma = 1+ln(2m-1)/ln m. Thus, by tuning m, the degree exponent can be adjusted in the range, 2 < gamma < 3. We also solve analytically a mean shortest-path distance d between two vertices for the tree structure, showing the small-world behavior, that is, d approximately ln N/ln K macro, where N is system size, and k macro is the mean degree. Finally, we consider the case that the number of offspring is the same for all vertices, and find that the degree distribution exhibits an exponential-decay behavior.

Journal Article↗
PubMed2002

High efficiency gene transfer to human CD34+ cells.

We have previously reported the development of improved MLV-based retroviral vectors whose prototype is entitled MT (Kim et al, J. Virol. 72:994-1044; Yu et al, Gene Therapy 7:797-804). The MT vector does not contain any viral coding sequences, and thus the possibility of homologous recombination between the vector and the packaging genome is virtually nil. Indeed, in a shotgun RCR detection assay, an MT-based vector did not produce any RCR. On the contrary, the MFG vector, containing parts of all three viral coding sequences (gag, pol, and env), generated a significant number of RCR. In addition to being safe, MT-based vectors produce levels of gene expression and viral titer comparable to or higher than other vectors currently available within the community. Based on this vector, we have constructed a number of retroviral vectors that can be used for the treatment of a variety of human diseases. Our major target diseases are those that can be treated with or the status of which can be significantly improved with bone marrow transplantation. To obtain the most significant therapeutic effects, it is necessary to achieve the highest possible gene delivery efficiency, drive the highest level of gene expression, and prevent expression of the inserted therapeutic gene from being negatively influenced by the genome environment. To these ends, we compared various LTRs for their effects on the level of gene expression, tested the effect of cis-acting elements that may influence chromatin structure or position effect of the inserted gene, and studied different transduction conditions for their gene delivery efficiency. Data recently obtained from these experiments will be presented.

Antigens, CD34↗
PubMed2002

IFN gamma/TNF alpha synergism in MHC class II induction: effect of nicotinamide on MHC class II expression but not on islet-cell apoptosis.

AIMS/HYPOTHESIS: Interferon-gamma (IFN gamma) and TNFalpha synergistically induce pancreatic beta-cell apoptosis. Apart from their direct effect, we studied the possible indirect immunological role of IFNgamma/TNFalpha synergism on pancreatic beta-cell death by investigating MHC class II induction by cytokines. The effect of nicotinamide on the cytokine-induced MHC class II expression and pancreatic beta-cell death was also studied. METHODS: Immunocytochemistry, flow cytometry and RNase protection assay were used to study MHC class II expression. Immunoblotting was done to study downstream signals of IFN gamma. The effects of nicotinamide on islet-cell apoptosis and diabetes mellitus were examined using MTT assay and adoptive transfer model. RESULTS: IFN gamma alone induced MHC class II expression on a small number of insulinoma cells. TNFalpha alone did not induce MHC class II expression, but enhanced IFN gamma-induced MHC class II expression. MHC class II expression by cytokine(s) was due to the induction of class II transactivator (CIITA). Nicotinamide reduced MHC class II expression by cytokine(s) but did not protect insulinoma-cell apoptosis by IFN gamma and TNFalpha in combination or protect against the development of diabetes mellitus after adoptive transfer of diabetogenic lymphocytes. CONCLUSION/INTERPRETATION: IFN gamma and TNFalpha synergistically induced MHC class II expression on insulinoma cells through the induction of CIITA; nicotinamide reduced the expression of cytokine-induced MHC class II expression on insulinoma cells through its effect on CIITA expression; and the preventive effect of nicotimamide on Type I (insulin-dependent) diabetes mellitus is probably due to its effect of MHC class II expression rather than that on islet cell apoptosis.

Animals↗
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

Three novel mutations of the PKD1 gene in Korean patients with autosomal dominant polycystic kidney disease.

Mutations at the PKD1 locus account for 85% of cases of the common genetic disorder called autosomal dominant polycystic kidney disease (ADPKD). Screening for mutations of the PKD1 gene is complicated by the genomic structure of the 5'-duplicated region encoding 75% of the gene. To date, more than 90 mutations of the PKD1 gene have been reported in the European and American populations, and relatively little information is available concerning the pattern of mutations present in the Asian populations. We looked for mutations of the PKD1 gene in 51 unrelated Korean ADPKD patients, using polymerase chain reaction (PCR) with primer pairs located in the 3' single-copy region of the PKD1 gene and by single-strand conformation polymorphism (SSCP) analysis. We found three novel mutations, a G to A substitution at nucleotide 11012 (G3601S), a C to A substitution at nucleotide 11312 (Q3701X), and a C to T substitution at nucleotide 12971 (P4254S), and a single polymorphism involving a G to C substitution at nucleotide 11470 (L3753L). These mutations were not found in control individuals, and no other mutations in the 3' single-copy region of the PKD1 gene of patients with these mutations were observed. In particular, P4254S segregated with the disease phenotype. The clinical data of affected individuals from this study, and of previously reported Korean PKD1 mutations, showed that patients with frameshift or nonsense mutations were more prone to develop end-stage renal failure than those with missense mutations. Our findings indicate that many different PKD1 mutations are likely to be responsible for ADPKD in the Korean population, as in the Western population.

Female↗
PubMed2002

Cyclin dependent kinase 5 and its interacting proteins in cell death induced in vivo by cyclophosphamide in developing mouse embryos.

Activation or inactivation of members of the cyclin-dependent kinase family is important during cell cycle progression. However, Cdk5, a member of this family that was originally identified because of its high structural homology to Cdc2, is activated during cell differentiation and cell death but not during cell cycle progression. We previously demonstrated a correlation between the up-regulation of Cdk5 protein and kinase activity and cell death during development and pathogenesis. We report here that cyclophosphamide (CP) induces massive apoptotic cell death in mouse embryos and that Cdk5 is expressed in apoptotic cells displaying fragmented DNA. During CP-induced cell death, Cdk5 protein expression is substantially increased as detected by immunohistochemistry but not by Western blot, while its mRNA level remains the same as control, and its kinase activity is markedly elevated. The up-regulation of Cdk5 during CP-induced cell death is not due to de novo protein synthesis. We also examined p35, a regulatory protein of Cdk5 in neuronal differentiation. Using a yeast two-hybrid system, we isolated p35, a neuronal differentiation specific protein, as a protein that interacts with Cdk5 in CP-treated embryos. p35 mRNA level does not change, but the protein expression of p25, a truncated form of p35, is elevated during cell death in vivo, as established here, as well as during cell death in vitro. Our results suggest a role for Cdk5 and its regulatory proteins during CP induced cell death. These results further support the view that Cdk5 and its regulation may be key players in the execution of cell death regardless of how the cell dies, whether through biological mechanisms, disease states such as Alzheimer's disease, or induction by CP.

Amino Acid Sequence↗
PubMed2002

Estrogen receptor beta is involved in the anorectic action of estrogen.

OBJECTIVE: Estrogen has been implicated in feeding behavior and adiposity. This study was undertaken to elucidate the mechanism underlying the anti-obesity and anorectic action of estrogen and the role of estrogen receptor (ER) in the central nervous system. METHODS AND RESULTS: Ovariectomy in 8-week-old female Wistar rats induced hyperphagia along with an increase in body weight and abdominal fat accumulation compared to control sham-operated rats. These changes were fully reversed by subcutaneous replacement of estradiol and were abrogated by pair-feeding. Then, the effects of intracerebroventricular infusion of estradiol, alone or in combination with antisense oligodeoxynucleotides (ODN), for ER in ovariectomized rats were examined. The estradiol group showed 10-20% lower daily food intake, and after the 2-week infusion period a 14% reduction in body weight with a similar reduction in abdominal fat compared to the vehicle group. The inhibitory effect of estradiol on food intake and body weight was blocked by co-administration of ER-beta antisense ODN, whereas ER-alpha antisense ODN did not show any influence. CONCLUSION: These results indicate that ER-beta in the central nervous system is involved in the anorectic action of estrogen.

Adipose Tissue↗
PubMed2002

Helicobacter pylori eradication therapy improves atrophic gastritis and intestinal metaplasia: a 5-year prospective study of patients with atrophic gastritis.

AIM: : To investigate the effect of the eradication of Helicobacter pylori on histological gastritis. METHODS: : Twenty-six patients with moderate to severe atrophy received successful eradication therapy of H.pylori. Four patients dropped out and 22 were followed up prospectively for 5 years. The grades of gastritis were estimated from gastric biopsy specimens. The grade of intestinal metaplasia was also evaluated by dye-endoscopy using methylene blue (methylthioninium chloride). The serum levels of pepsinogen, gastrin and anti-parietal cell antibody were also determined. RESULTS: : The grades of atrophy decreased in patients with successful eradication therapy in the gastric corpus (before vs. 5 years after eradication, 2.09 +/- 0.15 vs. 0.91 +/- 0.17; P < 0.01) and in the antrum (2.14 +/- 0.17 vs. 1.36 +/- 0.17; P < 0.01). The levels of intestinal metaplasia were also decreased in the corpus (0.91 +/- 0.24 vs. 0.50 +/- 0.16; P < 0.05) and in the antrum (1.41 +/- 0.20 vs. 1.00 +/- 0.16; P < 0.05), which was also demonstrated by the methylene blue (methylthioninium chloride) staining method (33.4 +/- 8.2% vs. 23.0 +/- 6.5%; P < 0.05). The improvement of corpus atrophy correlated well with the high serum level of pepsinogen I (P = 0.005), but showed no correlation with the levels of anti-parietal cell antibody. CONCLUSIONS: : These results suggest that gastric atrophy and intestinal metaplasia are reversible events in some patients.

Adult↗
PubMed2002

A six-canal maxillary first molar: case report.

AIM: The aim of this case report is to describe an unusual six-canal maxillary first molar tooth. CASE REPORT: The maxillary left first molar of a young African-American male was treated as an emergency at the first visit. At the second visit, the five canals (MB1 and 2, Pal1 and 2 and DB) were easily identified at high magnification of 16-25 under an operating microscope. The canals were then instrumented and filled using the Microseal technique. A careful radiographic examination of the final fill indicated that there was a third canal in the palatal root as suggested by a slight extrusion of the filling material between the two canals. At the third visit, the fillings of the palatal canals were removed and the apical 4mm was re-examined. The existence of a third palatal canal exiting between the two apices was verified and subsequently instrumented and obturated. KEY LEARNING POINTS: It should be assumed that all molar teeth have more than the traditionally expected three canals. The location of root canals should be identified at high magnification under the microscope. Careful radiographic re-examination of the fillings should be done in order to identify possibly missed canals.

Adult↗