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Biomedical subjects

S H Ko

Publications and source records attributed to S H Ko.

At least 19 recordsLinked to original sources
PubMed2006

Exendin-4 induction of cyclin D1 expression in INS-1 beta-cells: involvement of cAMP-responsive element.

Glucagon-like peptide-1 (GLP-1) and its analog exendin-4 (EX) have been considered as a growth factor implicated in pancreatic islet mass increase and beta-cell proliferation. This study aimed to investigate the effect of EX on cyclin D1 expression, a key regulator of the cell cycle, in the pancreatic beta-cell line INS-1. We demonstrated that EX significantly increased cyclin D1 mRNA and subsequently its protein levels. Although EX induced phosphorylation of Raf-1 and extracellular-signal-regulated kinase (ERK), both PD98059 and exogenous ERK1 had no effect on the cyclin D1 induction by EX. Instead, the cAMP-elevating agent forskolin induced cyclin D1 expression remarkably and this response was inhibited by pretreatment with H-89, a protein kinase A (PKA) inhibitor. Promoter analyses revealed that the cAMP-responsive element (CRE) site (at position -48; 5'-TAACGTCA-3') of cyclin D1 gene was required for both basal and EX-induced activation of the cyclin D1 promoter, which was confirmed by site-directed mutagenesis study. For EX to activate the cyclin D1 promoter effectively, CRE-binding protein (CREB) should be phosphorylated and bound to the putative CRE site, according to the results of electrophoretic mobility shift and chromatin immunoprecipitation assays. Lastly, a transfection assay employing constitutively active or dominant-negative CREB expression plasmids clearly demonstrated that CREB was largely involved in both basal and EX-induced cyclin D1 promoter activities. Taken together, EX-induced cyclin D1 expression is largely dependent on the cAMP/PKA signaling pathway, and EX increases the level of phosphorylated CREB and more potently trans-activates cyclin D1 gene through binding of the CREB to the putative CRE site, implicating a potential mechanism underlying beta-cell proliferation by EX.

Animals↗
PubMed2004

Expression of the intermediate filament vimentin in proliferating duct cells as a marker of pancreatic precursor cells.

OBJECTIVES: The expression of the intermediate filament (IF) vimentin, usually considered a marker of mesenchymal cells, has been observed in the epithelial cells during embryogenesis, carcinogenesis, and dedifferentiation, suggesting that it might be useful as a marker of proliferating precursor cells in the pancreas. METHODS: Rat pancreata at E18 and at different time points after partial pancreatectomy (Px) and human and neonatal pig pancreatic tissue sections and monolayer cultured pancreatic duct cells were observed. All tissues were simultaneously immunostained with pancytokeratin and vimentin antibodies. In costained duct cells, PDX-1 or PCNA expression was also analyzed using confocal microscope images. RESULTS: In the rat embryonic pancreas at E18, all epithelial cells that formed ductlike structures expressed both cytokeratin and vimentin IF, whereas no duct cells costained for IF in the adult rat or neonatal pig pancreas. Such costaining reappeared in the following order: common pancreatic duct, main ducts, foci of regeneration and then disappeared completely at 30 days after Px. In humans, costaining was found in only 1 diabetic patient's pancreatic section, which was accompanied by massive duct cell proliferation. In monolayer culture, most of the duct cells of human and neonatal pigs coexpressed both IF proteins. Only a few costained duct cells also expressed PDX-1, and most of those cells were also stained with PCNA in rat embryonic pancreas and regenerating foci after partial Px. CONCLUSIONS: Vimentin IF expression might be a useful marker for pancreatic precursor cells and could be used to investigate the concept of the dedifferentiation of fully matured duct cells during the process of the beta-cell neogenesis.

Animals↗
PubMed2001

Osteoclastogenesis is enhanced by activated B cells but suppressed by activated CD8(+) T cells.

Host immune response is known to contribute to the progression of periodontitis, and alveolar bone destruction in periodontitis is associated with enhanced osteoclast activity. Therefore, we evaluated the roles of activated lymphocyte subsets in osteoclastogenesis. Osteoclast precursors were co-cultured with activated lymphocytes (B, CD4(+) T, CD8(+) T) in the presence of either macrophage colony-stimulating factor (M-CSF) alone or M-CSF plus soluble receptor activator of NF-kappaB ligand (sRANKL), and subsequent differentiation into active osteoclasts was evaluated by a resorption assay. The activated B and CD4(+) cells, but not CD8(+) T cells, induced osteoclast differentiation in the presence of M-CSF alone. In the presence of M-CSF and sRANKL, B cells induced the formation of small but highly active osteoclasts and increased resorption, while CD8(+) T cells profoundly suppressed osteoclastogenesis. Co-culture using an insert well or supernatant suggested that both B and CD8(+) T cells acted on osteoclasts mostly via soluble proteins. Activated B cells expressed many osteoclastogenic factors including RANKL, TNF-alpha, IL-6, MIP-1alpha, and MCP-3. CD8(+) T cells expressed a substantial amount of osteoprotegerin (OPG) along with RANKL. However, blocking antibody to OPG did not reverse the suppression by CD8(+) T cells, suggesting that other factor(s) are involved. Taken together, activated B cells promoted osteoclastogenesis, while CD8(+) T cells inhibited the osteoclast formation via direct interaction. The results imply the importance of lymphocyte subpopulations in the development of periodontitis.

Animals↗
PubMed2001

Magnesium sulfate does not reduce postoperative analgesic requirements.

BACKGROUND: Because magnesium blocks the N-methyl-D-aspartate receptor and its associated ion channels, it can prevent central sensitization caused by peripheral nociceptive stimulation. However, transport of magnesium from blood to cerebrospinal fluid (CSF) across the blood-brain barrier is limited in normal humans. The current study was designed to evaluate whether perioperative intravenous magnesium sulfate infusion affects postoperative pain. METHODS: Sixty patients undergoing abdominal hysterectomy received 50 mg/kg intravenous magnesium sulfate as a bolus dose followed by a continuous infusion of 15 mg x kg(-1) x h(-1) for 6 h (magnesium group) or the same volume of isotonic saline (control group). At the end of surgery, serum and CSF magnesium concentration were measured in both groups. The cumulative postoperative analgesic consumption was measured to assess the analgesic effect using a patient-controlled epidural analgesia device. Pain intensities at rest and during forced expiration were evaluated at 6, 24, 48, and 72 h postoperatively. RESULTS: At the end of surgery, patients in the magnesium group had significantly greater postoperative serum magnesium concentrations compared with both preoperative and control group values (P < 0.001). Despite significantly higher serum magnesium concentrations in the magnesium group, there was no significant difference in magnesium concentration measured in postoperative CSF. Cumulative postoperative analgesic doses were similar in both groups. However, there was observed an inverse relation between cumulative postoperative analgesic consumption and the CSF magnesium concentration in both groups. Visual analog pain scores at rest and during forced expiration were similar and less than 4 in both groups. CONCLUSIONS: Perioperative intravenous administration of magnesium sulfate did not increase CSF magnesium concentration and had no effects on postoperative pain. However, an inverse relation between cumulative postoperative analgesic consumption and the CSF magnesium concentration was observed. These results suggest that perioperative intravenous magnesium infusion may not be useful for preventing postoperative pain.

Adult↗
PubMed2001

Hahella chejuensis gen. nov., sp. nov., an extracellular-polysaccharide-producing marine bacterium.

A bacterial strain, designated 96CJ10356T, which produced abundant extracellular polysaccharides and red pigment was isolated from marine sediment collected from Marado, Cheju Island, Republic of Korea. The organism is Gram-negative, aerobic, rod-shaped and motile. Growth was not observed in the absence of NaCl, and was optimal at an NaCl concentration of 2%. The strain contained oxidase and catalase, and was able to hydrolyse aesculin and gelatin. The major cellular fatty acids were saturated or monounsaturated straight-chain fatty acids. An almost complete 16S rDNA sequence of the test strain was determined. Phylogenetic analysis based on the neighbour-joining and Fitch-Margoliash methods indicated that the organism formed a distinct phyletic line within the gamma Proteobacteria. This relationship was also supported by sequence comparison, as no valid bacterial species showed more than 90% sequence homology with the isolate. It is clear from polyphasic evidence that the isolate merits the status of genus in the gamma subclass of the Proteobacteria, and the name Hahella chejuensis gen. nov., sp. nov. is proposed for the marine isolate 96CJ10356T (= KCTC 2396T = IMSNU 11157T).

Bacterial Typing Techniques↗
PubMed2001

Structure-borne noise reduction for an infinite, elastic cylindrical shell.

A theoretical model was developed to evaluate the reduction of structure-borne noise generated by an axially symmetric ring force which is applied on the interior of the cylindrical shell. The vibrating cylindrical shell is coated with a microvoided elastomer that is acoustically soft material designed for the reduction of the generated noise. The analytical model is a two-layer shell structure comprised of a cylindrical shell and an outer layer (coating) that is perfectly bonded to the cylindrical shell. The outer and inner surfaces of the coated shell are in contact with water and air, respectively. The analysis for this problem is based on the theory of elasticity, acoustic wave equations, and pertinent boundary conditions. Effects of various parameters such as coating thickness and material properties on the noise reductions are presented.

Journal Article↗
PubMed2001

Role of skin prick test and serological measurement of specific IgE in the diagnosis of occupational asthma resulting from exposure to vinyl sulphone reactive dyes.

OBJECTIVES: Some patients with occupational asthma resulting from exposure to reactive dyes have skin reactivity to the causative dyes and specific IgE to reactive dyes have been found in these patients. However, the usefulness of skin prick tests (SPTs) and serological measurement of specific IgE in screening, diagnosis, and monitoring the occupational asthma resulting from exposure to reactive dyes have not yet been assessed. In this study, the clinical validation of SPTs and measurement of specific IgE to vinyl sulphone reactive dyes by enzyme linked immunosorbent assay (ELISA) was evaluated. METHODS: 42 Patients with occupational asthma from reactive dyes (true positive group) were enrolled. In these the causative reactive dye was confirmed by bronchial challenge test. 93 Asymptomatic factory workers with negative challenge to the reactive dye (true negative group) and 16 unexposed controls with negative challenge to the reactive dye were also enrolled. Skin prick tests were done with 10 mg/ml reactive dye in 0.4% phenol/0.9% saline. IgE specific to reactive dye conjugated to human serum albumin (HSA) was measured with enzyme linked immunosorbent assays (ELISAs). RESULTS: None of the unexposed controls had a positive response to SPTs. The sensitivity (76.2% v 53.7%), specificity (91.4% v 86.0%), positive predictive value (80.0% v 62.9%), and negative predictive value (89.5% v 80.8%) of SPTs were higher than those of ELISAs. The mean weal size of reaction to reactive dye was weakly correlated with the ELISA optical density of IgE to reactive dye conjugate in patients with occupational asthma from reactive dyes (n=41, r=0.337, p<0.05). In four patients with occupational asthma from reactive dyes and eight control subjects exposed to reactive dye, IgE specific to reactive dye conjugated to HSA was detected with ELISA even though they showed negative skin reactivity. Six patients completely avoided the reactive dye for a mean (SD) 27.8 (10.3) months, IgE specific to reactive dyes decreased in all six patients (p<0.05) during this time. CONCLUSIONS: Both SPTs and detection of IgE specific to reactive dye in serum samples could be valuable for screening, diagnosis, and monitoring occupational asthma resulting from exposure to reactive dyes. These two tests would complement each other.

Adult↗
PubMed2001

Massive thrombosis after central venous catheterization in a patient with previously undiagnosed Behcet's disease.

Thrombosis is an important complication of central venous catheterization. Among the many intrinsic and extrinsic factors, the patient's medical disease can play a role in thrombogenesis. Behcet's disease (BD), classified as a vasculitis, is a multisystem disease involving the small blood vessels. It is often difficult to recognize and diagnose the disease. A 24-yr-old female patient showed massive central venous thrombosis which caused superior vena cava syndrome after subclavian vein catheterization. Twenty days after catheterization, the patient exhibited swelling of the face, neck, and both upper extremities. Despite thrombectomy and continuous anticoagulation therapy, her facial and upper extremity swelling reappeared and follow-up chest computed tomography (CT) showed the recurrent thrombosis in the same central veins previously affected. A diagnosis of BD was then made. Following steroid therapy, neither clinical symptoms nor CT findings suggestive of central venous thrombosis were observed during the subsequent 6-months of follow-up period. This case emphasizes that central venous catheterization in a patient with BD should be performed with great caution.

Adult↗
PubMed2001

Surgical treatment for concomitant fractures of the femoral neck and diaphysis: a treatment protocol.

Concomitant ipsilateral femoral shaft and neck fractures are difficult to treat. The standard protocol in our hospital is plates for diaphyseal fractures and lag screws or dynamic hip screws (DHS) fixations for the femoral neck fractures. We treated 21 patients with these complex fractures between 1988 and 1998 with this protocol. All patients were injured from high-energy trauma. There were 15 males and 6 females with an average age of 44 years. The average follow-up period is 50 months. All except one patient united well. During the follow-up period, neither non-union of the femoral neck fracture nor osteonecrosis of the femoral head was noted. There was also no malunion. There were twenty good results and one poor functional result. We conclude that plate on the shaft and sliding hip screws or separate screws in the hip are a reliable method for concomitant ipsilateral femoral neck and shaft fractures.

Adult↗
PubMed2000

Postero-medio-anterior approach of the ankle for the pilon fracture.

A good view of the operative field is important for better reduction and fixation in surgical treatment of fractures. The exposure of the ankle joint for the pilon fracture is commonly through the anterior approach, or combined with the medical approach. But sometimes it is still difficult to have complete viewing of the articular surface and to apply internal fixation by that approach. In recent years, we developed a "postero-medio-anterior" approach of the ankle joint by one incision. This approach provides an excellent exposure of the anterior, medial and posterior aspects of the ankle joint with a clear view of the articular surface. In our 45 cases of pilon fracture during 1991 to 1995, there was no incisional injury to the neurovascular bundle. Superficial wound edge necrosis was noted in two cases which healed later without further procedure. Therefore, we recommend this approach as a simple and reliable incision for open reduction of pilon fractures.

Adult↗
PubMed2000

IgE immune response to Ginkgo biloba pollen.

BACKGROUND: The ginkgo (Ginkgo biloba L.) continues to be planted as a shade tree in preference to other species in Seoul, Korea. The proportion of ginkgo to total shade trees was 43.2% in 1998, but the allergenic characteristics of ginkgo pollen has not been elucidated. OBJECTIVES: This study was undertaken to obtain information regarding the skin reactivity rate to ginkgo pollen in a population of Korean subjects with respiratory allergy. Possible ginkgo pollen allergens and the cross-reactivity of ginkgo pollen with other prevalent pollens were also examined. METHODS: Four hundred and forty-seven patients with asthma and/or allergic rhinitis were skin prick tested with extract of ginkgo pollen (1:20 wt/vol). Of these patients, positive skin responders (A/H ratio > or =2+) were selected for ELISA and immunoblot experiments. RESULTS: A total of 21 patients (4.7%) showed skin reactivity (A/H ratio > or =2+) to ginkgo pollen in the skin prick test. They were also cosensitized to many other tree, grass, and weed pollens. Sixteen (76%) of the 21 positive skin responders showed specific IgE responses to ginkgo pollen in ELISA. In inhibitory ELISA, IgE binding to ginkgo pollen was inhibited by more than 80% by oak, ryegrass, mugwort, and ragweed; and 34% by hop Japanese; and 10% by rBet v 2 at 10 microg/mL. In immunoblot, 10 out of 21 sera (48%) reacted to the 15-kD protein of ginkgo pollen, 9 (43%) to 33-35 kD, and 8 (38%) to 36-38 kD. In inhibitory immunoblot, IgE binding to ginkgo pollen proteins was almost completely inhibited by oak, ryegrass, mugwort and ragweed, but only partially by hop Japanese and rBet v 2. CONCLUSION: The skin reactivity rate to ginkgo pollen is approximately 4.7% in a population of Korean subjects with respiratory allergy. Since ginkgo pollen has a high cross-reactivity with other prevalent pollens, it could cause clinical symptoms during its pollen season by cross-reacting with the IgE produced in response to other pollens in patients sensitized to multiple pollens.

Adolescent↗
PubMed1999

Anaphylaxis to venom of the Pachycondyla species ant.

BACKGROUND: In the southeastern United States, imported fire ants have caused systemic reactions with a high incidence. On the contrary, in Korea Pachycondyla species ants (P chinensis and P solitaria), and the family Formicidae, which are in the genus Pachycondyla and the subfamily Ponerinae, have only occasionally caused systemic reactions. OBJECTIVE: We sought to assess whether commercially available imported fire ant extract would be useful in treating patients with anaphylaxis induced by venom from a Pachycondyla species ant. METHODS: Serum samples were collected from 2 women who had anaphylaxis induced by Pachycondyla species ant venom and from 6 volunteers with no history of having been stung. Specific IgE to Pachycondyla species ant extracts was measured by means of ELISA and possible allergenic components by immunoblot. Cross-reactivity between Pachycondyla chinensis, P solitaria, and imported fire ant extracts was also measured by inhibitory ELISA. RESULTS: Skin prick test responses were strongly positive to the extract of P chinensis (1:20 wt/vol) in the patient. Ten healthy volunteers exhibited negative responses. The 2 patients' sera exhibited high ELISA values, with absorbencies of 0.78 and 0.61 for P chinensis and 0.83 and 0.68 for P solitaria, respectively, and negative ELISA values for the extract of imported fire ants (absorbency <0.01). Imported fire ants showed no inhibition of the IgE binding to P chinensis or P solitaria. Possible allergenic components of Pachycondyla species ant extracts are 29- and 27-kd proteins and, less frequently, 16 kd proteins. CONCLUSION: Our data suggest that patients who have had an anaphylactic reaction to a Pachycondyla species ant might not benefit from immunotherapy with an imported fire ant extract. Immunotherapy with the extract of Pachycondyla species ants is expected to be highly effective.

Adult↗
PubMed1999

Cross-reactivity of Tyrophagus putrescentiae with Dermatophagoides farinae and Dermatophagoides pteronyssinus in urban areas.

BACKGROUND: Tyrophagus putrescentiae (TP) have cohabited with D. pteronys-sinus (DP) and D. farinae (DF) in more than 25% of houses in urban areas of Korea, and many atopic subjects have also been cosensitized to TP and Dermatophagoides species. OBJECTIVE: We evaluated the cross-reactivity of TP with DF and DP in atopic subjects of urban inhabitants. METHODS: The cross-reactivity was evaluated with inhibition ELISA and immunoblotting. Allergenic components of TP were evaluated with IgE immunoblotting of the sera from 25 individual atopics. All enrolled subjects lived in urban areas. RESULTS: In ELISA inhibition with pooled sera, all TP, DP, and DF extract inhibited TP-specific IgE by more than 90%, and the 50% inhibitory concentrations of TP, DP, and DF extract were 0.4 microg/mL, 0.8 microg/mL and 0.8 microg/mL, respectively. The maximum inhibition, however, of DP-specific and DF-specific IgE by TP extracts was 32% and 29%, respectively. With six individual sera, the TP-specific IgE was also inhibited by more than 88% with DF extract in all cases. In inhibition immunoblotting, all of the TP, DP, and DF extracts completely inhibited the TP-specific IgE bands at a concentration of 2.0 microg/mL. Fifteen allergenic components in TP were found. Among them, the 16-kD allergen was most prevalent (52%) and its IgE binding was completely inhibited by 0.1 microg/mL of purified Der f2 and it also bound with 2 different monoclonal antibodies to the group 2 allergen of Dermatophagoides species. CONCLUSIONS: Our results suggested considerable cross-reactivity between TP and the two Dermatophagoides species in urban areas where TP and Dermatophagoides species cohabit. The 16-kD allergen, which shared common epitopes with the group 2 allergen of Dermatophagoides, is one of the most prevalent allergens of TP.

Air Pollution, Indoor↗
PubMed1999

Identification and characterization of the major allergen of the Humulus japonicus pollen.

BACKGROUND: Pollen of Humulus japonicus has been known as one of the important causes of pollinosis in Korea and China. To date, the major allergen of H. japonicus has not been determined. OBJECTIVE: To identify the major allergen of H. japonicus pollen and characterize its biochemical properties. METHODS: With the sera of 29 patients reactive to H. japonicus, the major allergen of H. japonicus was determined from the results of IgE immunoblotting and ELISA inhibition. The biochemical properties of the major allergen of H. japonicus were evaluated by lectin blotting assay and 2-dimensional PAGE blot. N-terminal amino acid sequences were determined by the Edman degradation method. The suggested major allergen was purified by DEAE anion exchange and gel filtration chromatography. RESULTS: Twenty-nine sera contained IgE bound to the 10, 16, 20, 29 and 42 kDa proteins of H. japonicus in immunoblot analysis. A protein of 10 kDa was the most prevalent allergen in the sera of H. japonicus-reactive patients (72%). The ELISA optical density of H. japonicus-specific IgE was not inhibited by pollen extracts of birch, oak, rye grass and mugwort. The 10-kDa allergen was neither stained with PAS nor bound with ConA and five other lectins. The isoelectric point of the 10-kDa allergen was approximately pH 5.1. We sequenced the N-terminal amino acids of the 10-kDa allergen, which was not homologous with any previously characterized allergen. The 10-kDa allergen could be purified with DEAE anion exchange and gel filtration chromatography. Maximum inhibitions of H. japonicus-specific IgE ELISA by whole extract of H. japonicus and purified 10-kDa allergen were more than 97 and 88%, respectively, while the 50% inhibitory concentration of the whole extract of H. japonicus and purified 10 kDa were 38 and 20 ng/mL, respectively. CONCLUSION: The 10-kDa peptide could be a major allergen of H. japonicus. Its isoelectric point was 5.1 and it did not bind with lectins. The N-terminal amino acid sequence of the 10-kDa major allergen was also determined.

Adult↗
PubMed1999

Effect of a mixed culture on co-oxidation during the degradation of saturated hydrocarbon mixture.

Two bacterial strains, Pseudomonas aeruginosa K1 and Rhodococcus equi P1, were used to degrade cyclo-alkanes (such as decalin) by a co-oxidation mechanism. Both strains possessed the capacity to degrade a broad range of n-alkane mixtures (C7 to C28) within 24 h of incubation. Strain P1 rapidly degraded 10 gl-1 pristane within 24 h of incubation (mu = 0.36 h-1 and Yx/s = 0.6). The addition of hexadecane as a growth substrate (above 0.5%, v/v) resulted in complete degradation of 1% (v/v) decalin by strain P1 via a co-oxidation mechanism. Co-oxidation to degrade decalin or pristane by strain K1 proved unsuccessful. Strain P1 was able to degrade decalin totally in a saturated hydrocarbon mixture. Strain K1 was only able to degrade hexadecane from the hydrocarbon mixture, but its degradation rate was higher than that of strain P1. Therefore, there was competition for the hexadecane needed to co-oxidize decalin. As a result, degradation of the hydrocarbon mixture, especially decalin, was incomplete in a mixed culture of strain P1 and K1. Serial addition of hexadecane (twice) allowed complete degradation of the remaining decalin by strain P1. Also, the biodegradation rate of the hydrocarbon mixture by a microbial population from gasoline-contaminated soil was delayed by addition of strain K1 to the population, while the addition of strain P1 resulted in an increase in the biodegradation rate.

Alkanes↗
PubMed1998

Difference in H2O2 toxicity between intact renal tubules and cultured proximal tubular cells.

The present study was undertaken to examine the response to H2O2 and t-butylhydroperoxide (t-BHP) in various in vitro model systems of renal proximal tubules: rabbit renal cortical slices, freshly isolated rabbit proximal tubules, rabbit primary cultured proximal tubular cells, and opossum kidney (OK) cells. t-BHP increased lactate dehydrogenase release and lipid peroxidation in a concentration-dependent manner over the concentration range of 0.2 to 3 mM in cortical slices, whereas H2O2 caused a similar concentration-dependent increase in both parameters at 5-100 mM. The sensitivity of isolated tubules to both peroxides was similar to that of cortical slices. In primary cultured cells and OK cells, however, the cytotoxicity of H2O2 was identical to that of t-BHP. The cytotoxicity of t-BHP was not different among all the systems examined. The specific activity of catalase in cortical slices was similar to that of isolated tubules, but it was much higher than that of primary cultured cells or opossum kidney cells. Glutathione (GSH) peroxidase activity was not different among all the systems examined. The expression of catalase mRNA in cortical slices and isolated tubules was higher than that in primary cultured cells, whereas those of superoxide dismutase, glutathione peroxidase, or beta-actin were not different among the systems. These results indicate that intact proximal tubules are more resistant to H2O2 than are cultured proximal tubular cells, and the resistance is due to a higher specific activity of catalase resulting from the increased expression of its mRNA.

Animals↗
PubMed1998

Expression of a recombinant branched chain alpha-oxo acid dehydrogenase complex E2 (BCOADC-E2) in insect cells and its immunoreactivity to autoimmune sera.

Preparation of a pure autoantigen by way of recombinant DNA technology has an important value in an accurate diagnosis or prognosis of an autoimmune disease. BCOADC-E2 subunit, a mitochondrial protein, has been known to be the autoantigen of primary biliary cirrhosis (PBC), a chronic autoimmune liver disease, as well as idiopathic dilated cardiomypathy (IDCM), a chronic autoimmune heart disease. Recombinant form of this molecule had been expressed in E. coli but with low yield and severe degradation. Furthermore, sera from IDCM patients failed to recognized BCOADC-E2 molecule produced in prokaryotic expression system. In this study, a recombinant bovine BCOADC-E2 fusion protein has been expressed in insect cells using baculovirus expression system and analyzed anti-BCOADC-E2 reactivity in sera from patients with PBC or with IDCM. Optimal production of the recombinant fusion protein has been achieved at 20 multiplicity of infection (MOI), and the protein was affinity-purified using metal-binding resins. The affinity-purified BCOADC-E2 protein was successfully recognized by sera from PBC patients, but not by sera from IDCM patients suggesting that the different auto-immune response against BCOADC-E2 is needed to be elucidated in terms of epitope recognition.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗