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Biomedical subjects

C H Kim

Publications and source records attributed to C H Kim.

At least 73 records · Page 4Linked to original sources
PubMed2001

Reconstruction of basement membrane in skin equivalent; role of laminin-1.

To reconstruct the basement membrane in a skin equivalent, the epidermodermal interface was coated with porcine type IV collagen and mouse laminin-1 at various ratios before keratinocyte seeding. Laminin-1, a component of the basement membrane, induced massive infiltration of keratinocytes into the dermal equivalent, while type IV collagen induced discrete demarcation between dermal and epidermal compartments without any infiltrating cells. Immunohistochemical staining indicated that the laminin-induced infiltrating cells expressed endogenous type IV collagens at the cell periphery, which were not incorporated into the basement membrane structure. The infiltrating cells did not express fibronectin receptor alpha5beta1 integrin but showed MMP-9 secretion and cell surface associated MMP-2. However, when laminin-1 was preincubated with type IV collagen, laminin-1-induced keratinocyte infiltration as well as MMP-9 induction were almost completely suppressed to basal levels. Therefore, replenishment of the type IV collagen lattice seemed to cause laminin-stimulated cells to anchor to the lattice, in a similar manner to the basal cells on the basement membrane of normal skin. Our study suggests that the molar ratio of basement membrane components may determine the behavior of basal cells within the wound healing microenvironment, which is probably regulated either by extracellular matrix deposition or degradation.

3T3 Cells↗
PubMed2001

Hyperbaric oxygenation pretreatment induces catalase and reduces infarct size in ischemic rat myocardium.

Ischemia-reperfusion injury is a major complication occurring in heart stroke, cardiopulmonary bypass surgeries, and heart transplantation. Reactive oxygen species generated during the reperfusion phase overwhelm the scavenging capacities of antioxidant enzymes, and result in oxidative damage to the myocardium. We examined whether hyperbaric oxygenation (HBO) pretreatment induces antioxidant enzymes and protects the heart from subsequent ischemia-reperfusion injury. Rats were intermittently exposed to 100% O2 at 3 ATA (where ATA is absolute atmosphere) for 1 h daily and then sacrificed after 24 h of recovery in room air. Isolated hearts were subjected to 40 min of ischemia and 90 min of reperfusion. HBO pretreatment was found to condition the heart and enhance enzymatic activity and gene expression of catalase, thereby significantly reducing infarct size after reperfusion. A catalase inhibitor, 3-amino-1,2,4-triazole, completely abolished the infarct-limiting effect of HBO pretreatment, which suggests that HBO-induced tolerance against ischemia-reperfusion injury is due to catalase induction. Our results imply that HBO preconditioning may be developed as a new preventive measure for reperfusion injury in the heart.

Amitrole↗
PubMed2001

Increased expression of endoglin in the eutopic endometrium of women with endometriosis.

OBJECTIVE: To compare the angiogenic activities of endothelial cells in the eutopic endometrium of women with and without endometriosis. DESIGN: Vessels with active angiogenesis were identified using the monoclonal antibody to endoglin. SETTING: University department of obstetrics and gynecology. PATIENT(S): Twenty women with histologically confirmed endometriosis after laparotomy or laparoscopy. Women with carcinoma in situ of uterine cervix, but no evidence of endometriosis (n = 20), served as control subjects. INTERVENTION(S): Formalin-fixed, paraffin-embedded archival tissues were sectioned and stained. MAIN OUTCOME MEASURE(S): Number of vessels stained with monoclonal antibody to endoglin. RESULT(S): For all menstrual phases, the mean number of vessels with endoglin expression was significantly greater in patients with endometriosis compared with control subjects. In each menstrual phase, a significant difference was observed only during the late secretory phase. Within the group with endometriosis, the mean numbers of vessels with endoglin expression in stages I and II were not different from the numbers in stages III and IV. CONCLUSION(S): This study shows the expression of endoglin in the eutopic endometrium of women with endometriosis is significantly increased and the increase is observed only in the late secretory phase. It is suggested from these findings that activation of angiogenesis in the eutopic endometrium might be a key factor in the pathogenesis of endometriosis.

Adult↗
PubMed2001

The methylenetetrahydrofolate reductase gene polymorphism in Koreans with coronary artery disease.

Hyperhomocysteinemia is a known risk factor of cardiovascular diseases. Methylenetetrahydrofolate reductase (MTHFR), involved in folate-dependant metabolism, is associated with homocysteine levels. We studied the associations among MTHFR genotypes, coronary artery disease (CAD), and homocysteine levels in 85 patients with CAD and 152 healthy subjects. The MTHFR genotypes and plasma homocysteine levels were determined. No significant difference in mutation of the MTHFR gene between two groups was observed (P>0.05). While the homozygous mutant genotype (V/V) had the highest homocysteine levels compared to wild (A/A) and heterozygous mutant (A/V) genotypes, there were no significant differences in homocysteine levels among the MTHFR genotype groups. Homocysteine was significantly and inversely related to folate levels, the significant association in V/V genotype (beta coefficient=-1.954, P=0.04). Our data suggested that MTHFR polymorphism was not associated with homocysteine levels, implying no association between gene polymorphism and CAD in Koreans.

Aged↗
PubMed2001

Microalbuminuria is associated with the insulin resistance syndrome independent of hypertension and type 2 diabetes in the Korean population.

To investigate whether microalbuminuria is associated with the insulin resistance syndrome independent of hypertension and type 2 diabetes, we studied the association between microalbuminuria and features of insulin resistance syndrome in Korean general population. We selected 1006 subjects by a random cluster sampling among residents aged >40 years living in the Chung-Up district, a rural area of South Korea. Subjects were stratified by oral glucose tolerance status [normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and diabetes mellitus], and by the presence or absence of hypertension. Urinary albumin excretion rate (UAER) was determined using timed overnight urine collection. Various cardiovascular risk factors including anthropometric indices, serum lipid, true insulin and proinsulin concentrations were also measured. The prevalence of microalbuminuria (UAER between 20 and 200 microg/min) increased as the glucose tolerance worsened (6.0% in NGT, 11.8% in IGT, and 21.8% in diabetes; chi(2) trend=25.9, P<0.001). Subjects with microalbuminuria had a higher body mass index (BMI), waist-to-hip circumference ratio (WHR), systolic and diastolic blood pressure (BP), fasting and 2 h plasma glucose, fasting plasma insulin and proinsulin levels, and lower HDL-cholesterol level than subjects without microalbuminuria. In multiple regression analysis, BMI, diastolic BP, 2 h plasma glucose, and fasting plasma insulin levels were found to be independent factors associated with UAER. Multiple logistic regression analysis showed that not only diabetes mellitus and hypertension, but also fasting hyperinsulinemia and waist-to-hip ratio were independent factors associated with the presence of microalbuminuria. When the normotensive, non-diabetic subjects were analyzed separately, fasting hyperinsulinemia and impaired glucose tolerance remained independent variables associated with the presence of microalbuminuria. These results show that microalbuminuria in the Korean general population is associated with hyperinsulinemia and central obesity, and suggest that microalbuminuria is a feature of the insulin resistance syndrome independent of hypertension or type 2 diabetes.

Adult↗
PubMed2001

Effects of intravenous infusion of amino acids and glucose on the yield and concentration of milk protein in dairy cows.

To test the hypothesis that the availability of glucose or its precursors can influence the response of milk protein concentration to the intravenous infusion of amino acids, five cows were used in a 5 x 5 Latin square design with period lengths of 7 d. The five treatments were the basal diet of grass silage ad lib. plus 5 kg/d of a cereal-based supplement containing feather meal (Basal); Basal plus 4 g/d histidine, 8 g/d methionine and 26 g/d lysine (4H); Basal plus 8 g/d histidine, 8 g/d methionine and 26 g/d lysine (SH); and these two amino acid mixtures together with 600 g/d of gluctose (4HG and 8HG respectively). Earlier experiments with this basal diet had shown that histidine was first-limiting for secretion of milk protein, followed by methionine and lysine. The yield of milk protein was increased progressively with the amount of histidine infused. The efficiency of transfer of histidine into milk protein was 0.42 for the 4H and 4HG and 0.35 for the 8H and 8HG treatments, and the concentration of milk protein was increased over Basal by all infusion treatments. However, milk protein concentrations were higher, and lactose concentrations in the milk were lower, in the absence of added glucose. Concentrations of insulin in blood plasma were not affected by treatment. It is concluded that, with the treatments without added glucose, a shortage of glucose prevented an increase in lactose secretion, and hence limited the increase in milk yield, leading to an increased concentration of protein in the milk.

Amino Acids↗
PubMed2001

Molecular cloning and functional expression of the rfaE gene required for lipopolysaccharide biosynthesis in Salmonella typhimurium.

The rfaE (WaaE) gene of Salmonella typhimurium is known to be located at 76min on the genetic map outside of the rfa gene cluster encoding core oligosaccharide biosynthesis of lipopolysaccharide(LPS). The rfaE mutant synthesizes heptose-deficient LPS; its LPS consists of only lipid A and 3-deoxy-D-manno-octulosonic acid (KDO), and the rfaE gene is believed to be involved in the formation of ADP-L-glycero-D-manno-heptose. Mutants, which make incomplete LPS, are known as rough mutants. Salmonella typhimurium deep-rough mutants affected in the heptose region of the inner core often show reduced growth rate, sensitivity to high temperature and hypersensitivity to hydrophobic antibiotics. We have cloned the rfaE gene of S. typhimurium. The chromosomal region carrying this gene was isolated by screening a genomic library of S. typhimurium using the complementation of S. typhimurium rfaE mutant. The 2.6-Kb insert in the plasmid pHEPs appears to carry a functional rfaE gene. SL1102 (rfaE543) makes heptose-deficient LPS and has a deep rough phenotype, but pHEPs complement the rfaE543 mutation to give the smooth phenotype. The sensitivity of SL1102 to bacteriophages (P22.c2, Felix-O, Br60) which use LPS as their receptor for adsorption is changed to that of wild-type strain. The permeability barrier of SL1102 to hydrophobic antibiotics (novobiocin) is restored to that of wild-type. LPS produced by SL1102 (rfaE543) carrying pHEPs makes LPS indistinguishable from that of smooth strains. The rfaE gene encoded a polypeptide of 477 amino acid residues highly homologous to the S. enterica rfaE protein (98% identity), E. coli (93% identity), Yersenia pestis (85% identity), Haemophilus influenzae (70% identity) and Helicobacter pyroli (41% identity) with a molecular weight 53 kDa.

Amino Acid Sequence↗
PubMed2001

Ovarian hyperstimulation syndrome complicating a spontaneous singleton pregnancy: a case report.

It has been known that most cases of ovarian hyperstimulation syndrome (OHSS) are associated with the use of exogenous gonadotropins to induce multiple ovulation. However, OHSS is infrequently associated with a spontaneous ovulatory cycle, usually in the case of multiple gestations, hypothyroidism, or polycystic ovarian syndrome. We report a case of severe OHSS in a spontaneously pregnant woman with no underlying disease.

Adult↗
PubMed2001

Separable effector T cell populations specialized for B cell help or tissue inflammation.

We identified specialized B helper and tissue inflammatory CD4(+) T cell subsets that developed concurrently from common naïve precursors during the primary immune response. These separable populations were distinguishable by their expression of adhesion and chemoattractant receptors that directed their homing to the appropriate effector sites in vivo and also showed intrinsic differences in their ability to support B cell antibody production and produce effector cytokines in vitro. Thus, our data show a previously unappreciated functional specialization among CD4(+) effector T cells, further defining their diversity and role in adaptive immunity.

Animals↗
PubMed2001

Responses of milk production to the intravenous infusion of amino acids in dairy cows given diets of grass silage and cereal-based supplements.

Three experiments were carried out to examine responses of milk production to the intravenous infusion of amino acids in dairy cows given diets of grass silage and supplements based on barley, with or without added soyabean meal and ranging in crude protein content from 16 to 19% in dry matter. Particular attention was given to histidine, administered alone or in combination with methionine, lysine and tryptophan. Responses of milk protein secretion to infusion of histidine were seen only when the diet contained a supplement of barley alone. When soyabean meal was included, there were no responses of milk production to infusion of any of the infused amino acids. Calculations suggested that, although histidine remained first-limiting when soya was included in the diet, any response to infusion of histidine was blocked by the rapidly emerging deficiency of another amino acid, probably leucine. The results confirm that, for diets based on grass silage and supplements of cereal only, histidine is first-limiting such that increases of milk protein secretion can be obtained in response to infusion of histidine alone. In assessing the practical significance of this finding, it should be remembered that greater responses in the yield of milk protein can probably be obtained by substituting 1 kg of soyabean meal for 1 kg of cereal, which is likely to be an easier and cheaper option.

Amino Acids↗
PubMed2001

Structural and functional characterization of the 5' upstream promoter of the human Phox2a gene: possible direct transactivation by transcription factor Phox2b.

The specification of neurotransmitter identity is a critical step in neural development. Recent progresses have indicated that the closely related homeodomain factors Phox2a and 2b are essential for development of noradrenergic (NA) neuron differentiation, and may directly determine the neurotransmitter identity. With a long-term goal of understanding the regulatory cascade of NA phenotype determination, we isolated and characterized a hPhox2a genomic clone encompassing approximately 7.5 kb of the 5' upstream promoter region, the entire exon-intron structure, and approximately 4 kb of the 3' flanking region. Using mRNAs isolated from the Phox2a-expressing human cell line, both primer extension and 5'-rapid amplification of cDNA ends analyses identified a single transcription start site that resides 172 nucleotides upstream of the start codon. The transcription start site was preceded by a TATA-like sequence motif and transcripts from this site contained an additional G residue at the 5' position, supporting the authenticity of this site as the transcriptional start site of hPhox2a. We assembled hPhox2a-luciferase reporter constructs containing different lengths of the 5' upstream sequences. Transient transfection assays of these reporter constructs in both hPhox2a-positive and -negative cell lines show that 1.3-kb or longer upstream sequences of the hPhox2a gene may confer NA cell-specific reporter gene expression. Furthermore, cotransfection assays in the Phox2a-negative HeLa cell line show that forced expression of Phox2b, but not that of Phox2a or MASH1, significantly transactivates the transcriptional activity of hPhox2a. This study will provide a frame to further delineate the regulatory cascade of NA neuron differentiation.

Amino Acid Sequence↗
PubMed2001

Enhancement of cephalosporin C production by cultivation of Cephalosporium acremonium M25 using a mixture of inocula.

AIMS: To enhance the productivity of Cephalosporin C (CPC) by cultivation of Cephalosporium acremonium M25 using a mixture of inocula. METHODS AND RESULTS: Inoculum age was classified into three stages (early, intermediate and late) by image analysis. A mixture of inocula, according to the inoculum ages, was used for efficient production of CPC in the main culture. The most effective mixing ratio of inocula for CPC production in shake flasks was a 3 : 7 volume ratio of early- and late-stage inocula. This was also the case in a 1.5 l stirred-tank reactor. CPC productivity was enhanced by about 32% and 34% when using an inoculum mixture in the shake flask and 1.5 l stirred-tank reactor, respectively. CONCLUSION: The morphological characteristics of C. acremonium M25 in the seed culture were quite different according to inoculum age. The compromise of different ages of inoculum showed better production of CPC. SIGNIFICANCE AND IMPACT OF THE STUDY: The productivity of CPC was enhanced considerably when using mixed inocula. The results of this study can be applied to fungal cultures for efficient production of various metabolites.

Acremonium↗
PubMed2001

Codon 54 polymorphism of the fatty acid binding protein 2 gene is associated with increased fat oxidation and hyperinsulinemia, but not with intestinal fatty acid absorption in Korean men.

The alanine to threonine substitution at codon 54 (Ala54Thr) of the fatty acid binding protein 2 (FABP2) gene has been reported to be associated with increased fat oxidation and insulin resistance in several populations. It has been hypothesized that Ala54Thr substitution results in enhanced intestinal uptake of fatty acids and thereby an impairment of insulin action, but this hypothesis has not been proven in vivo. We studied the association between the Ala54Thr polymorphism of the FABP2 gene and intestinal (3)H-oleic acid absorption, as well as basal insulin level, basal metabolic rate, and fat oxidation rate in 96 healthy young Korean men. Among our subjects, the allele frequency of the Ala54Thr substitution was 0.34. Subjects with Thr54-encoding allele were found to have a higher mean fasting plasma insulin concentration and a higher basal fat oxidation rate compared with the subjects who were homozygous for the Ala54-encoding allele. However, there was no significant difference in basal metabolic rate or (3)H-oleic acid absorption according to the FABP2 gene polymorphism. These results suggest that the Ala54Thr substitution in the FABP2 gene is associated with increased fat oxidation and hyperinsulinemia in normal Korean men, but these effects are not mediated by an increase in the intestinal fatty acid absorption.

Animals↗
PubMed2001

Expression of the proliferating cell nuclear antigen and clinicopathological features in intracranial meningiomas.

PC10, a monoclonal antibody (mAb) to proliferating cell nuclear antigen (PCNA) is known to show immunoreactivity in paraffin-embedded specimens. The authors present the relation between PCNA expression and clinicopathological features in 38 intracranial meningiomas. PCNA scores were obtained by immunohistochemical staining of the paraffin-embedded sections using a streptavidin-biotin immunoperoxidase method with PC10 mAb. Univariate analysis showed that high PC10 scores were associated with old age (> or = 50 years old), male, recurrent tumours, and meningothelial type. However, these high scores did not reach a statistical significance (P> 0.05). PC10 scores of the basal meningioma tended to be higher than that of the hemispheric meningioma (P< 0.05). The staining intensity of PCNA was also markedly increased in basal meningiomas. It is suggested that the proliferative potential is higher in basal meningiomas than in hemispheric meningiomas. Moreover, these results could reflect high recurrence and difficulty in management of the skull base meningiomas.

Adult↗
PubMed2001

Expression of bisecting N-acetylglucosaminyltransferase-III in human hepatocarcinoma tissues, fetal liver tissues, and hepatoma cell lines of Hep3B and HepG2.

In this paper, uridine diphosphate (UDP)-N-acetylglucosamine/beta-D-mannoside beta-1,4 N-acetylglucosaminyltransferase III (GlcNAc-transferase-III C 2.4.1.144) activity was determined in human hepatoma cell lines of Hep3B and HepG2, and also compared with those of normal liver tissues and primary hepatocytes. GlcNAc-transferase-III enzymes of Hep3B and HepG2 were mainly detected in the membrane fraction. When GlcN,GlcN-biant-PA and UDP-GlcNAc were used as substrates, the Km values (4.7 mM for UDP-GlcNAc and 1.1 mM for GlcN, GlcN-biant-PA) of Hep3B GlcNAc-transferase-III were distinguishable from those of HepG2 GlcNAc-transferase-III (6.8 mM for UDP-GlcNAc and 3.4 mM for GlcN,GlcN-biant-PA). Furthermore, Hep3B enzyme in membrane fraction showed about 1.5-fold higher specific activity (1423 pmol/hr/mg) than that of HepG2 (1066 pmol/hr/mg). Normal liver cells and primary adult hepatocytes are characterized by a very low level of GlcNAc-transferase-III activity, whereas human hepatoma cells exhibited high activities. These data were supported by reverse transcription-polymerase chain reaction results, showing that expression of the GlcNAc-transferase-III mRNA increased in proportion to the enzymatic activities. Although the mechanism underlying the induction of this enzyme is unknown, lectin blot analysis showed that oligosaccharides in many glycoproteins were observed in hepatoma cells. By treating hepatocarcinoma cultures that express GlcNAc-transferase-III with inhibitors (tunicamycin, deoxymannojirimycin, and swainsonine) of different steps of the glycosylation, we provide evidence that expression of GlcNAc-transferase-III mRNA is dependent on glycosylation of cellular proteins.

Adult↗