Biomedical subjects

S I Kim

Publications and source records attributed to S I Kim.

At least 127 records · Page 7Linked to original sources

PubMed1998

Ginsenoside Rh2 and Rh3 induce differentiation of HL-60 cells into granulocytes: modulation of protein kinase C isoforms during differentiation by ginsenoside Rh2.

Ginsenoside Rh1 or Rh2 differentiated B16 melanoma or F9 teratocarnoma to phenotypic normal melanocyte-like cells or parietal endoderm-like cells. Ginsenoside Rh3 and Rh4 were recently isolated from Panax ginseng, but their biochemical and pharmacological effects remain unidentified. The present study investigated whether the ginsenoside Rh group (G-Rh1, -Rh2, -Rh3 and -Rh4) having similar structures induce differentiation of HL-60 cells and whether protein kinase C (PKC) is involved in differentiation by ginsenoside. Differentiation was assessed by Wright-Giemsa stain and nitroblue tetrazolium reduction. G-Rh2 and G-Rh3 induced differentiation of HL-60 cells into morphologically and functionally granulocytes but G-Rh1 and G-Rh4 did not. G-Rh2 and G-Rh3 arrested the cell cycle at the G1/S phase, consistent with the ability to induce differentiation in a decreasing order of retinoic acid > G-Rh2 > G-Rh3. During differentiation by G-Rh2, Ca2+/phospholipid-dependent PKC activity was increased in both the cytosol and total cell extract and Ca2+/phospholipid-dependent phosphorylation of 38 and 200 kDa endogenous proteins increased, while phosphorylation of 60, 64, 66 and 97 kDa proteins was Ca2+/phospholipid-independent. When cytosolic PKC isoforms were analyzed by immunoblotting, no significant change was observed in the alpha level, however, the immunoreactive 60 kDa band of a similar mass to the PKC catalytic fragment appeared following treatment with G-Rh2. The beta isoform was gradually increased with prolonged treatment. The gamma isoform was not detected in the cytosol of untreated cells, whereas a small amount was detected 5 days after treatment. It is concluded that G-Rh2 and G-Rh3 can induce differentiation of HL-60 cells into granulocytes and modulation of PKC isoform levels may contribute to differentiation of HL-60 cells by G-Rh2.

Antineoplastic Agents, Phytogenic↗

PubMed1998

HLA haplotypes in Koreans based on 107 families.

There are marked differences in the distribution of HLA haplotypes among different populations, and multilocus HLA haplotypes can best be studied by family analysis. In the present study, 107 Korean families were analyzed for HLA-A, B, C, DR, and DQ antigens and haplotypes. Allele frequencies of more than 10% for class I antigens were A2, A24, A33, B44, B62, Cwl, Cw7, Cw9, Cw10, and C blank (CBL) and those for class II antigens were DR4, DR8, DR13, DR15, DQ1, DQ3, DQ4 and DQ7. In the analysis of HLA haplotypes, 18 kinds of A-B-DR and 11 kinds of A-C-B-DR-DQ haplotypes occurred at frequencies of more than 1%, comprising 34% and 24% of the total theoretical haplotypes, respectively. The five most common A-B-DR haplotypes were exclusively related with the five most common A-C-B-DR-DQ haplotypes (frequency>2%). These remarkably conserved five-locus haplotypes in Koreans were A33-CBL-B44-DR13-DQ1 (5.4%), A24-Cw7-B7-DR1-DQ1 (3.5%), A33-Cw7-B44-DR7-DQ2 (3.0%), A33-Cw10-B58-DR13-DQ1 (2.3%), and A30-Cw6-B13-DR7-DQ2 (2.3%). Comparison of the distribution of A-B-DR haplotypes among East Asian populations revealed that Koreans are closest to Japanese, but show a higher degree of polymorphism in the distribution of HLA haplotypes compared to Japanese. The results obtained in this study will be useful as basic data on Koreans for anthropology and organ transplantation.

Alleles↗

PubMed1998

Platelet activating factor antagonist activity of ginsenosides.

Ginseng saponins and their degradation products have been screened for antagonist activity towards [3H]PAF (platelet activating factor) in washed rabbit platelet receptor binding studies. 20(S)- and delta20-ginsenosides Rg3, protopanaxadiol-type saponins, were found to be relatively potent PAF antagonists (IC50 = 4.9 x 10(-5) M and 9.2 x 10(-5) M, respectively).

Animals↗

PubMed1998

Membranoproliferative glomerulonephritis associated with HCV infection in native kidneys and renal allograft.

Hepatitis C viral infection occurs relatively low in Korea compared to hepatitis B. However, it progresses into chronic hepatitis and cirrhosis more frequently than HBV. It may be associated with cryoglobulinemia and glomerulonephritis, both in native and transplanted kidneys. We report three cases of membrano-proliferative glomerulonephritis type I in anti-HCV positive, but cryoglobulin-negative patients, presenting massive proteinuria, two in native kidneys and one in an allograft. HCV-RNA was positive in sera of two patients. Two were cirrhotic and ALT was mildly elevated in two. In addition to the characteristic membranoproliferative feature, two native kidneys overlapped with features of diabetic nephropathy. Immunofluorescence demonstrated mainly IgM and C3 deposits along the peripheral capillary walls. Subendothelial electron dense deposits were present in the glomeruli of all three cases with subepithelial and intramembranous deposits in two. HCV-RNA was associated not only with a greater amount of immune deposits but also with subepithelial and intramembranous deposits, indicating the role of active infection.

Adult↗

PubMed1998

A Clonorchis sinensis-specific antigen that detects active human clonorchiasis.

A Clonorchis sinensis-specific antigen in excretory-secretory product of C. sinensis (CsE) was assessed in human clonorchiasis by immunoblot. Thirty and 7 kDa antigens of CsE2, one of four different batches of CsEs reacted strongly with infection sera from clonorchiasis patients; however, the antigens reacted weakly with 6-month post-treatment sera from praziquantel-cured cases, but were still highly detected by the sera from praziquantel-failed patients, indicating that the 30 and 7 kDa antigens can detect antibodies during an active infection. The 30 kDa antigen showed some cross reactions with sera from patients with Paragonimus westermani and Metagonimus yokogawai, while the 7 kDa antigen did not, suggesting that the 7 kDa antigen has high specificity. The 30 kDa antigen reacted with some past clonorchiasis sera, whereas the 7 kDa antigen did not, supporting that antibodies to the 7 kDa antigen are not present in sera from past clonorchiasis patients. In an endemic area, 92% (23/25) of active clonorchiasis patients and 91% (10/11) of mixed infection patients with C. sinensis and M. yokogawai had IgG antibodies to the 7 kDa antigen, while 40% (6/15) of past clonorchiasis individuals and 43% (3/7) of metagonimiasis patients cross-reacted to the antigen. These data suggest that the 7 kDa antigen in an excretory-secretory antigen may serve as a marker of an active clonorchiasis with reliable specificities in past clonorchiasis, paragonimiasis and metagonimiasis.

Animals↗

PubMed1998

A case of Behçet's disease with superior and inferior vena caval occlusion.

Behçet's disease is a chronic multisystemic disorder involving many organs and characterized by recurrent oral and genital ulcers and relapsing iritis. A case of BD with large vein thrombosis involving superior and inferior vena cava is presented. Large vein thrombosis in BD is not commonly developed and most commonly observed in the inferior or superior vena cava. A review of the literature emphasizes the rarity of the combined superior and inferior vena caval occlusion. Existence of extensive large vein occlusion in BD is associated with limited therapy and poor prognosis.

Adult↗

PubMed1998

Femoral anteversion: estimation by 3D modelling.

Femoral anteversion is the inclination of the femoral neck axis with reference to the tangent plane of the distal femur. For estimating femoral anteversion, following three major parameters are required; the neck axis, the long axis, the knee axis. Conventional methods on the basis of 2D images are ambiguous to determine these major axes. As the femur has a complex 3 dimensional structure, the 3 dimensional model should be applied for accurate and reliable measurement of femoral anteversion. In this paper, we model femur and define three parameters. The neck axis is defined from the femoral head and neck model. The long axis is determined from the cylindrical model of the femoral shaft. The knee axis is also determined from the model of femoral condyles. According to the definition of the femoral anteversion, the femoral anteversion is efficiently estimated from these models. 30 specimens were tested by conventional 2D imaging method, 3D imaging method which was developed by authors and the new 3D modelling method. The study provides accurate, fast and human factor free measurement for femoral anteversion.

Algorithms↗

PubMed1998

Detection of epileptiform activities in the EEG using neural network and expert system.

This paper proposes a multichannel spike detection in long term EEG monitoring for epilepsy. It is achieved by wavelet transform(WT), artificial neural network(ANN) and the expert system. First, a small set of wavelet coefficients is used to represent the characteristics of a single channel epileptic spikes and normal activities. The purpose of this WT is to reduce the number of inputs to the ANN. Next, three layer feed-forward network employing the error back propagation algorithm is trained and tested using parameters obtained by the WT. Spikes are identified in individual EEG channels by 16 identical neural networks. Finally, 16-channel expert system based on the context information of adjacent channels is introduced to reject artifacts and produce reliable results. In this study, epileptic spikes and normal activities were selected from 32 patient's EEGs (the seizure disorder: 12, normal: 20) in consensus among experts. The result shows that the WT reduced data input size and the preprocessed ANN had 97% sensitivity and 89.5% selectivity, which were more accurate than that of ANN with the same input size of raw data. In clinical result, our expert rule system, which uses neighboring channel informations, was capable of rejecting artifacts commonly found in EEG recordings.

Adolescent↗

PubMed1998

Is kidney graft biopsy indicated in recipients with newly developed, microscopic hematuria?

We actively performed renal allograft biopsies on 87 living donor renal transplant recipients presenting with stable serum creatinine but showing newly developed recurrent microscopic hematuria with a small amount of proteinuria during the maintenance phase of immunosuppression and found definite pathological lesions in 56 cases (64%). Chronic rejection of a mild grade (n = 27) and various kinds of glomerulonephritis (n = 27) were the major pathological diagnoses, and from 14 cases singular or complicated cyclosporine (CsA) toxicity was found. Twenty-four out of the 27 glomerulonephritis cases were IgA nephropathy, which is the most common glomerulonephritis in Korea. Through this study, the authors found chronic rejection or glomerulonephritis even in grafts which are generally considered to be normal. CsA nephrotoxicity, which was not expected clinically, could be found. In summary, renal allograft biopsy on patients, even with stable graft function when they start to show microscopic hematuria with or without a small amount of proteinuria, should be performed to document the early intragraft events if there are no medical contraindications.

Adult↗

PubMed1998

The role of prior knowledge and elaboration in text comprehension and memory: a comparison of self-generated elaboration and text-provided elaboration.

Four experiments investigated the interactive effect of text-provided elaborations and prior knowledge on text comprehension and memory. Subjects read 28 episodes, half of which were associated with well-known people and the other half with unknown people. In Experiment 1, text-provided elaborations enhanced recall only when the reader did not have a high level of prior knowledge. The findings from Experiment 1 were hypothesized to be the result of readers generating relevant elaborations during text comprehension. Experiment 2 supported this hypothesis by providing evidence of self-generated elaborations. The results from Experiments 3 and 4 extended these findings by showing that readers with high prior knowledge automatically generate causally relevant elaborations when the sentences have a low relation.

Adult↗

PubMed1997

Improvement of the production of foreign proteins using a heterologous secretion vector system in Bacillus subtilis: effects of resistance to glucose-mediated catabolite repression.

To improve protein production, a heterologous secretion vector system was constructed with the aid of the amyR2 region. The operator sequence (amyO) of the amyR2 region on the secretion vector was changed through site-directed mutagenesis to eliminate carbon-source-mediated catabolite repression. Three substitutional (AG, G5, G10), one deletional (delta HH), and one insertional (AGHF) mutant promoters were obtained. The expression level and the degree of catabolite repression of amyR2 and the mutant promoters were examined with a single copy system using an integrational promoter probe vector, pDH32. Under glucose-free culture conditions, expression levels from all mutant promoters except HH were 1.4 to 1.5 fold higher than that from amyR2. While the expression of the amyR2 promoter was repressed by 90% in the presence of 2% glucose, expression levels of the mutant promoters were repressed by only 1% to 50%. To evaluate the advantage of the mutant promoters in production of foreign proteins by the heterologous secretion system, beta-lactamase and human pancreatic secretory trypsin inhibitor (hPSTI) were expressed by the mutant promoters. When B. subtilis LKS87 was used as a host strain, the production of the target proteins using the respective mutant promoter was increased by about 1.5 fold under glucose-free culture conditions. Under the high glucose culture conditions, secretion of target proteins produced from the mutant promoters increased 1.5 to 2 fold, whereas those by the amyR2 promoter were reduced to between 50% and 60%. The additive effect of degUh mutation on protein production was not observed under high glucose culture conditions. In addition, such culture conditions inhibited proteolytic degradation of secreted target proteins after the stationary growth phase even in B. subtilis LKS88 (degUh mutant). Thus, our results indicated that the mutant promoters, which are resistant to glucose-mediated catabolite repression, are very useful for over-production of foreign proteins under the high glucose culture conditions using the heterologous expression-secretion system in B. subtilis.

Bacillus subtilis↗

PubMed1997

Synthesis of ginsenoside Rg3, a minor constituent of Ginseng radix.

Glycosylation of 12beta-acetoxy-dammar-24-en-3beta,20(S)-diol (4), with hepta-O-acetyl-alpha-sophorosyl bromide (5) under catalysis by Ag2CO3 or Ag2O afforded a chromatographically unseparated mixture of the alpha- and beta-linked octaacetates 6 and 7 in an approximately 2.5:1 ratio. After deprotection and chromatographic purification, the free alpha- (8) and beta-glycosides (9) were obtained. Sophoroside 9 was identical in all respects with ginsenoside Rg3, the minor component of Ginseng Radix rubra. All compounds were fully characterized by 1H and 13C NMR spectroscopy.

Acetylation↗

PubMed1997

Peptide mapping and amino acid sequencing of two catechol 1,2-dioxygenases (CD I1 and CD I2) from Acinetobacter lwoffii K24.

The partial amino acid sequences of two catechol 1,2-dioxygenases (CD I1 and CD I2) from Acinetobacter lwoffii K24 have been determined by analysis of peptides after cleavages with endopeptidase Lys-C, endopeptidase Glu-C, trypsin, and chemicals (cyanogen bromide and BNPS-skatole). They include 248 amino acid sequences (4 fragments) of CD I1 and 211 amino acid sequences (5 fragments) of CD I2. Two enzymes have more than 50% sequence homology with type I catechol 1,2-dioxygenases and less than 30% sequence homology with type II catechol 1,2-dioxygenases. Two enzymes have similar hydropathy profiles in the N-terminal region, suggesting that they have similar secondary structures.

Acinetobacter↗

PubMed1997

Effects of pleiotrophic mutations, degUh and spoOA, on the production of foreign proteins using the heterologous secretion system of Bacillus subtilis.

To elevate the production of foreign target proteins using a heterologous protein secretion system of Bacillus subtilis, two different pleiotrophic mutations, degUh for increase of transcriptional level of target genes and spoOA for reduction of extracellular protease activity of a host strain were introduced, respectively. The productivities of three differently originated enzymes, beta-lactamase, streptokinase and human pancreatic trypsin inhibitor (hPSTI) were examined under the each mutation background. By the degUh mutation, the activities of all three enzymes secreted in the culture were increased, although the increased levels were different from 1.2-fold (streptokinase) to 1.8-fold (beta-lactamase). The lower productivity of streptokinase compared to other enzymes under the degUh background was caused by the higher susceptibility to proteolytic degradation. The increased transcriptional level of the beta-lactamase gene by degUh mutation resulted in the accumulation of unprocessed precursor protein in the cytoplasm and cytoplasmic membrane. In the case of the spoOA mutation background, the differences in the levels of the secreted target proteins were not significant and observed only after a stationary phase of the growth.

Bacillus subtilis↗

PubMed1997

Post-transplantation diabetes is better controlled after conversion from prednisone to deflazacort: a prospective trial in renal transplants.

It is well known that long-term use of steroids plays a decisive role in the development of glucose intolerance and diabetes mellitus (DM). Deflazacort, an oxazoline derivative of prednisolone, has been introduced as a potential substitute for conventional steroids in order to ameliorate glucose intolerance. We initiated a randomized study of conversion from prednisone to deflazacort in kidney transplantation (Tx) recipients presenting with pre-Tx or post-Tx DM to ascertain whether or not the switch to deflazacort would ameliorate the diabetic state. Forty-two recipients in the conversion group were compared with 40 patients on prednisone (the control group) in a prospective manner. The dose reduction of insulin or oral blood glucose-lowering agents, the adequacy of glucose control, and the development of side effects were the criteria for evaluating outcome. In the conversion group, patients were switched to a deflazacort at a dose ratio of 6 mg deflazacort to 5 mg prednisone. During the mean follow-up period of 13.2 months, neither graft dysfunction nor acute rejection developed in the conversion group. Improvement in blood glucose control in the conversion group was noted. When the conversion group was stratified into pre- or post-Tx DM, promising effects were clearly evident in the post-Tx DM patients. More than 50% dose reduction of blood glucose-lowering agents was possible in 42.3% of post-Tx DM patients. In conclusion, it was readily possible to control blood glucose better in post-Tx DM recipients without seriously affecting the immunosuppressive activity after conversion to deflazacort.

Adult↗

PubMed1997

Cloning of the gene encoding the catalytic subunit of casein kinase II from the yeast Yarrowia lipolytica.

Casein kinase II from the yeast Yarrowia lipolytica is a heterotetramer of the form alpha alpha' beta 2. We report on the cloning and sequencing of a partial cDNA and of the complete genomic DNA coding for the catalytic alpha subunit of the casein kinase II from this yeast species. The sequence of the gene coding for this enzyme has been analyzed. No intron was found in the gene, which is present in a single copy. The deduced amino acid sequence of the gene shows high similarity with those of alpha subunit described in other species, although, uniquely, Y. lipolytica CKII alpha lacks cysteines. We find that the alpha subunit sequence of Y. lipolytica CKII is shown greater homology with the corresponding protein from S. pombe than with that from S. cerevisiae. We have analyzed CKII alpha expression and CKII alpha activity. We show that expression of this enzyme is regulated. The catalytic subunit is translated from a single mRNA, and the enzyme is present at a very low level in Y. lipolytica, as in other yeasts.

Amino Acid Sequence↗

PubMed1997

Involvement of IMP dehydrogenase activity in induction of sporulation of Bacillus cereus.

IMP dehydrogenase activity of B. cereus increased parallel to cell growth in YE-EMM, where B. cereus did not sporulate. When B. cereus was cultured in a modified G medium, a sporulation medium, the activity reached the highest level at 6 hr and decreased thereafter. After induction of sporulation by nutritional shift down in 1/100 G medium, the enzyme activity decreased to about 5% compared with exponentially growing cells at 1 hr of resuspension. The sporulation rate of B. cereus was over 90% in the modified G medium and 1/100 G medium. Sporulation was strongly inhibited by mycophenolic acid at 1 mM, when the drug was added at 0 and 1 hr of resuspension in 1/100 G medium. Intracellular GTP concentration of B. cereus decreased to the lowest level about 1 hr of resuspension. Although GTP increased to about 50% of the exponentially growing cells at 2 hr of resuspension in control cells, the concentration did not increase in the presence of 1 mM mycophenolic acid.

Bacillus cereus↗

PubMed1997

Protective effects of red ginseng saponins against carbon tetrachloride-induced hepatotoxicity in Sprague Dawley rats.

The protective effects of red ginseng saponins against carbon tetrachloride-induced hepatotoxicity were investigated in male Sprague Dawley rats. The total saponins of red ginseng standardized on ginsenosides-Rb1, -Rb2, -Rc, -Rd, -Re, and -Rg1 were used in the present study. The rats were administered the standardized saponins of red ginseng orally at 50, 100, and 200 mg/kg for 7 consecutive days, followed by an administration of carbon tetrachloride at 0.4 ml/kg in corn oil intraperitoneally for 24 h. The administration of saponin changed neither body and organ weights nor hematological and serum clinical parameters. The elevation of SGPT and SGOT activities induced by carbon tetrachloride was partially recovered by the administration of the saponin. The liver vacuolization and lymphoid cell aggregation by carbon tetrachloride were clearly recovered by the red ginseng saponins as examined histologically. The present results indicated that the standardized saponins of red ginseng used in these studies may partially recover the hepatotoxicity induced by carbon tetrachloride in male Sprague Dawley rats.

Animals↗