Biomedical subjects

J M Oh

Publications and source records attributed to J M Oh.

12 recordsLinked to original sources

PubMed2003

Classification of lake sediments using a hydrocyclone.

The present work is a preliminary experiment for hydrocyclones as a primary process in lake sediment thickening. A few cyclones based on the Rietema standard geometry were prepared, and sample particles were sediments from a local lake and waste coal fly ash for a reference test. As a result of the chemical analysis, more organic contaminants were found in smaller particles. The experimental tests showed that physical characteristics of particles, configuration of the cyclone and operation conditions could affect the separation efficiency.

Centrifugation↗

PubMed2001

A database of protein expression in lung cancer.

We have developed a comprehensive approach to identifying molecular changes in lung cancer that includes both genomic and proteomic analyses. The related effort has produced a large amount of data pertaining to gene expression at the RNA and protein levels. As a result, we have constructed a database that contains protein expression data on lung cancer as well as other relevant data including DNA microarray derived data. A large number of proteins that are expressed in different types of lung cancer have been identified and have been correlated with the expression measures for their corresponding genes at the RNA level. The database is intended to facilitate our effort at developing novel classification schemes for lung cancer and the identification of novel markers for early diagnosis.

Biomarkers, Tumor↗

PubMed2001

Promoted expression of mast cell-specific proteases in IgE-dependent passive cutaneous anaphylaxis responses.

BACKGROUND: Various factors can influence the protease expression phenotype of mast cells. METHODS: In an effort to understand the potential role of the mast cell proteases in the IgE-dependent passive cutaneous anaphylaxis (PCA) responses of murine tissues, we studied the changes of proteases expression. The expressions of proteases were examined by Northern blotting and immunohistochemistry. RESULTS: Promoted expression phenotypes of mouse mast cell protease (mMCP)-4, and rat mast cell protease I were accompanied by initiation of anti-dinitrophenyl (DNP) IgE-induced PCA responses, suggesting that the induction of these proteases expression are associated with IgE-mediated anaphylaxis responses. Elevated level of the L-histidine decarboxylase (HDC) mRNA expression was also observed in the PCA tissues and the activated mast cells, compared with that of the corresponding control tissue and cells, due to the activation of mast cells. CONCLUSIONS: Promoted protease expression phenotype appears to be linked with the induction of HDC expression.

Animals↗

PubMed2001

Sodium nitroprusside induces apoptosis of H9C2 cardiac muscle cells in a c-Jun N-terminal kinase-dependent manner.

Sodium nitroprusside (SNP) induces apoptosis in H9C2 cardiac muscle cells. Treatment with an exogenous NO donor SNP (2 mM) to H9C2 cells resulted in apoptotic morphological changes; a bright blue-fluorescent condensed nuclei and chromatin fragmentation by fluorescence microscope of Hoechst 33258-staining. The activity of caspase-3 like protease was increased during SNP-induced cell death. However, the activity of caspase-1 like protease was not affected by SNP. Pretreatment with Z-VAD-FMK (a pan-caspase inhibitor) or Ac-DEVD-CHO (a specific caspase-3 inhibitor) abrogated the SNP-induced cell death. SNP markedly activated three MAP kinases (JNK/SAPK, ERK and p38 MAP kinase) in the cardiac muscle cells. In this study, selective inhibition of the ERK or p38 MAPK pathway (by PD98059 or SB203580, respectively) had no effect on the extent of SNP-induced apoptosis in cardiac muscle cells. In contrast, inhibition of the JNK pathway by transfection of a dominant negative mutant of JNK markedly reduced the extent of SNP-induced cell death. Taken together, we suggest that JNK/SAPK will be related to SNP-induced apoptosis of H9C2 cardiac muscle cells.

Amino Acid Chloromethyl Ketones↗

PubMed2001

Thermal inactivation kinetics and application of phospho- and galactolipid-degrading enzymes for evaluation of quality changes in frozen vegetables.

Lipid-acyl hydrolases (LAHases) play significant roles in lipid degradation during the storage of vegetables. In particular, spinach contains a large portion of galactolipids (59.5%) and phospholipids (22.4%) among its fat-soluble components, which are used as substrates for LAHases. Thermal inactivation of various LAHases, including phospholipases A, C, and D, phosphatase, and galactolipase, from spinach and carrot was investigated to optimize the blanching process prior to the frozen storage of vegetables. Thermostability of phospholipase C or galactolipase was greatest among the LAHases from both spinach and carrot. Galactolipase from spinach exhibited a D value of 3.39 x 10(2) s at 80 degrees C and a z value of 8.21 degrees C, whereas phospholipase C from spinach showed D(80) of 1.72 x 10(2) s with a z value of 9.26 degrees C. In the case of LAHases from carrot, the D(65) and z values of galactolipase were 6.66 x 10(2) s and 8.69 degrees C, respectively, whereas phospholipase C displayed D(85) of 3.12 x 10(2) s and a z value of 15.8 degrees C. Highly active and thermostable galactolipase and phospholipase C in spinach and carrot made it possible for them to be used as indicator enzymes for the determination of quality deterioration of the stored vegetables.

Food Handling↗

PubMed2001

Comparison of azathioprine and mycophenolate mofetil for the prevention of acute rejection in recipients of pancreas transplantation.

The study was performed to compare the efficacy and side effects of azathioprine (AZA) and mycophenolate mofetil (MMF) in conjunction with cyclosporine or tacrolimus and steroids for the prevention of acute pancreas rejection during the first 6 months of pancreas transplantation. In this case-controlled study, MMF is compared with historical controls of AZA in the prevention of acute pancreas rejection. The primary measures of treatment efficacy were patient and pancreas survival rate at 6 months after transplantation. Secondary efficacy measures were the occurrence of biopsy-proven pancreas rejections and the use of antilymphocyte preparations for rejection treatment. A total of 111 pancreas transplant patients (57 in the AZA group and 54 in the MMF group) were evaluated. The 6-month patient survival rate was 96% in the AZA group versus 97% in the MMF group (p = 0.57). The 6-month pancreas graft survival rate was 88% in the AZA group versus 91% in the MMF group (p = 0.29). However, biopsy-proven rejection episodes during the first 6 months of transplantation were significantly lower with MMF (46%) than with AZA (69%) (p = 0.01). In addition, patients in the AZA group received a greater number of full courses of antilymphocyte therapy as a rejection treatment (p = 0.004). Overall, the frequency of adverse events was similar, although the MMF group experienced higher incidences of gastrointestinal adverse events. In conclusion, compared with AZA, MMF significantly reduces the rate of biopsy-proven pancreas rejection during the first 6 months of transplantation and is well tolerated, except for gastrointestinal adverse events.

Acute Disease↗

PubMed2000

Human chorionic gonadotropin induces nitric oxide synthesis by murine microglia.

This study investigated the effects of human chorionic gonadotropin (hCG) on the synthesis of nitric oxide (NO) in murine neonatal microglial cells. When hCG was used in combination with interferon-gamma (IFN-gamma), there was a marked cooperative induction of NO synthesis in a dose-dependent manner. This increase in NO synthesis was reflected as an increased amount of iNOS protein. The increase of NO synthesis by IFN-gamma-plus-hCG was associated with the increase of tumor necrosis factor-alpha (TNF-alpha) secretion and hCG-induced NO production was decreased by the treatment with anti-murine TNF-alpha neutralizing antibody. This study provides evidence that hCG activates expression of iNOS protein in murine microglial cells accompanied by NO accumulation via pathway dependent on L-arginine in the culture medium, and further offers that TNF-alpha acts on the NO synthesis from IFN-gamma-primed murine microglial cells.

Animals↗

PubMed2000

Mouse monoclonal antibodies to hepatitis B virus preS1 produced after immunization with recombinant preS1 peptide.

We have efficiently generated mouse monoclonal antibodies (MAbs), which bind specifically to amino acids 21-47 of the preS1 domain of hepatitis B virus (HBV) by immunizing mice with the preS1 peptide (amino acids, aa 1-56) conjugated to keyhole limpet hemocyanin. Hybridomas were screened by an indirect enzyme-linked immunosorbent assay (ELISA) using the purified preS1 peptide as a coated antigen. Eighteen positive hybridomas were selected and subjected to isotyping. Of these, 5 clones secreted immunoglobulin G (IgG) and 13 clones secreted IgM. Four (KR1, KR2, KR3, and KR4) of the 5 IgG MAbs bound to preS1 peptide (aa 21-47). Epitope mapping using bacterially expressed GST fusion proteins revealed that three clones (KR2, KR3, KR4) (IgG1, K) recognize aa 21-35, while KR1 (IgG2a, K) recognizes aa 35-47 of the preS1. These MAbs immunoprecipitated HBV particles, demonstrating that they bind to native HBV particles.

Animals↗

PubMed1998

Genetic structure of the bphG gene encoding 2-hydroxymuconic semialdehyde dehydrogenase of Achromobacter xylosoxidans KF701.

2-Hydroxymuconic semialdehyde dehydrogenase catalyzes the conversion of 2-hydroxymuconic semialdehyde (HMS) to an enol form of 4-oxalocrotonate which is a step in the catechol meta-cleavage pathway. A bphG gene encoding HMS dehydrogenase of A. xylosoxidans KF701, a soil bacterium degrading biphenyl, was identified at between catechol 2,3-dioxygenase gene and HMS hydrolase gene, and its sequence was analyzed. An open reading frame (ORF) corresponding to bphG gene was consisted of 1461 nucleotides with ATG initiation codon and TGA termination codon. The ORF exhibited 66% of G + C content, and a putative ribosome-binding sequence, AGAGA, was identified at about 10 nucleotides upstream initiation codon of the bphG gene. The bphG gene can encode a polypeptide of molecular weight 52 kDa containing 486 amino acid residues. A deduced amino acid sequence of HMS dehydrogenase encoded in bphG gene from A. xylosoxidans KF701 exhibited the highest 94% homology with that of corresponding enzyme encoded in xylG from P. putida mt-2, 63% to 90% homology with those of other reported HMS dehydrogenases, and 29% to 42% homology with those of betaine aldehyde dehydrogenase, 5-carboxy-HMS dehydrogenase, aldehyde dehydrogenase, indole-3-acetaldehyde dehydrogenase, succinic semialdehyde dehydrogenase, methylmalonate semialdehyde dehydrogenase, and succinylglutamate 5-semialdehyde dehydrogenase. From an alignment of amino acid sequence of HMS dehydrogenase from A xylosoxidans KF701 with other reported dehydrogenases, putative cofactor NAD(+)-binding regions and catalytic residues were identified.

Alcaligenes↗

PubMed1998

Immunohistochemical study of 3beta-hydroxysteroid dehydrogenase/delta5-delta4 isomerase in the rat cardiovascular system.

The enzyme complex 3beta-hydroxysteroid dehydrogenase (3beta-HSD) is involved in the biosynthesis of all classes of active steroids. It is known that the enzymatic activity of 3beta-HSD is present not only in classical steroidogenic tissues, but also in many peripheral tissues including cardiac tissue. To determine whether 3beta-HSD is present in rat non-steroidogenic tissues, we examined cardiovascular tissues including the ventricle, atrium, aortic arch, abdominal aorta, and inferior vena cava by immunohistochemistry and Western blotting using polyclonal antibody raised against a synthetic peptide of human placental 3beta-HSD. By Western blotting, protein bands immunoreactive for anti-3beta-HSD were detected at molecular weights of 42 and 37 kDa in both the ventricle and atrium, whereas only a 37 kDa band was recognized in both the aortic arch and abdominal aorta. By immunohistochemistry, immunoreactivity for 3beta,-HSD was detected in both the ventricular and atrial cardiocytes, while immunostaining was also found, though faintly, in the smooth muscles of the aortic arch, abdominal aorta, and inferior vena cava. These results suggest that cardiocytes may synthesize the steroidogenic 3beta,-HSD enzyme.

Animals↗

PubMed1997

Structure of catechol 2,3-dioxygenase gene encoded in TOM plasmid of Pseudomonas cepacia G4.

The catechol 2,3-dioxygenase is an extradiol-type dioxygenase which cleaves the C-C bond at the meta position of catechol to form 2-hydroxymuconic semialdehyde. A catechol 2,3-dioxygenase gene (tomB) in the TOM plasmid of P. cepacia G4 has been cloned and its nucleotide sequence was analyzed. The enzyme gene consisted of 945 base pairs with an ATG initiation codon and a TGA termination codon which can encode a polypeptide of molecular weight 35 kDa containing 314 amino acid residues, and a putative ribosome-binding sequence was identified at approximately 10 nucleotides upstream of the initiation codon. The deduced amino acid sequence of catechol 2,3-dioxygenase from P. cepacia G4 exhibited 79-82% homologies with those of 3-methylcatechol 2,3-dioxygenase of P. putida UCC2 and catechol 2,3-dioxygenase of P. pickettii PKO1.

Amino Acid Sequence↗

PubMedDate not supplied

Mining protein data from two-dimensional gels: tools for systematic post-planned analyses.

There is a considerable need to develop comprehensive, systematic mechanisms to analyze the vast number of proteins that orchestrate various cellular functions and to identify proteins associated with disease or that are affected by pharmacological agents. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) continues to be relied upon to analyze protein constituents of cells and tissues. We have developed a Laboratory Information Processing System (LIPS) as a computer-based tool for capturing quantitative and qualitative changes in thousands of proteins detected in 2-D gels of various types. Protein databases have been developed to serve as a repository for data processing of the basic and derived data and of findings derived from different studies. There have been remarkable advances both in database technology as well as in the computer hardware that have benefited our effort at mining protein data from 2-D gels. We here review our current efforts aimed at improving the performance and features of our 2-D related protein databases, with particular emphasis on the tools we utilize for database mining via a systematic analysis of information known as post-planned analysis.

Acrylic Resins↗