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1.
Ann Clin Biochem ; 39(Pt 1): 56-61, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11853190

ABSTRACT

BACKGROUND: Apolipoprotein concentrations in reflex tears from healthy and noninsulin-dependent diabetes mellitus (NIDDM) subjects were measured and correlated with the stage of diabetic retinopathy. METHODS AND RESULTS: The apolipoprotein A-I (apo A-I) concentrations in the tears from NIDDM patients with retinopathy were significantly higher than those from patients with no or negligible retinopathy (P<0.05), and apo A-I was not detected in healthy subjects by Western blotting. No reactive band was detected on apo A-I by Western blotting for nitrotyrosine, a marker for peroxynitrite oxidation of the tear proteins. Apo A-I concentration in tears was significantly correlated with the stage of retinopathy (r= 0.598, n = 59, P < 0.001). No apo A-I gene expression was detected in the conjunctiva by reverse transcription polymerase chain reaction. CONCLUSIONS: We conclude that there is increased secretion of native apo A-I from the main lacrimal gland in patients with advanced diabetic retinopathy.


Subject(s)
Apolipoprotein A-I/metabolism , Diabetes Mellitus, Type 2/metabolism , Diabetic Retinopathy/metabolism , Eye Proteins/metabolism , Tears/metabolism , Aged , Apolipoprotein A-I/genetics , Conjunctiva/metabolism , Electrophoresis, Polyacrylamide Gel , Eye Proteins/isolation & purification , Humans , Lacrimal Apparatus/metabolism , Middle Aged
2.
J Hematother Stem Cell Res ; 10(5): 703-7, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11672517

ABSTRACT

The subclass I enzyme of rat pyrimidine 5'-nucleotidase (P5N-I), which preferentially hydrolyzes (deoxy)CMP and UMP, is distributed specifically in red blood cells (RBCs), and its activity increases approximately six-fold as compared to the control value after erythropoietic induction by phenylhydrazine administration. In this study, we detected rat P5N-I protein by using antibodies against the chicken P5N-I enzyme. The molecular mass of rat P5N-I was approximately 37 kDa, as estimated by gel filtration chromatography and Western blot analysis. The pI value of the enzyme was approximately 5.7. This protein band was detected only in RBC lysate extract, i.e., not in cytosol from the erythropoietic spleen. Protein mass of the P5N-I enzyme, estimated by immunoblot analysis, was increased in proportion to the enzyme activity after erythropoietic induction in rats. No phosphorylation of the enzyme protein was detected by immunoblot analysis with anti-phosphoserine or anti-phosphotyrosine antibody. In conclusion, these findings indicate that the rat P5N-I enzyme is expressed specifically in reticulocytes and may therefore be essential in the maturation process of rat erythrocytes.


Subject(s)
5'-Nucleotidase/biosynthesis , Erythrocytes/physiology , 5'-Nucleotidase/isolation & purification , Animals , Blotting, Western , Erythrocytes/enzymology , Erythropoiesis/drug effects , Phenylhydrazines/pharmacology , Rats , Reticulocytes/enzymology , Time Factors
3.
Biochem Biophys Res Commun ; 287(3): 714-20, 2001 Sep 28.
Article in English | MEDLINE | ID: mdl-11563854

ABSTRACT

Glycation of plasma proteins may contribute to an excess risk of developing atherosclerosis in patients with diabetes mellitus. Although it is believed that high-density lipoprotein (HDL) is nonenzymatically glycosylated at an increased level in diabetic individuals, little is known about a possible linkage between glycated HDL and endothelium dysfunction in diabetes. This study set out to clarify whether glucose-modified HDL affects the function of endothelial cells by examining the apoptosis of cultured human aortic endothelial cells (HAECs) exposed to a glycated-oxidized HDL (gly-ox-HDL) prepared in vitro. Incubation of HAECs with 100 microg/ml of gly-ox-HDL for 48 h showed apoptotic features, such as cell shrinkage, membrane blebbing, and concentration and fragmentation of the nucleus, and the degree of apoptosis was dose-dependent on the glucose used in the preparation of gly-ox-HDL. Stimulation of HAECs with gly-ox-HDL elicited a marked increase in caspase 3 activity and the expressions of active caspase 3 and caspase 9, whereas concomitant treatment with a caspase 3 inhibitor significantly blocked gly-ox-HDL-induced apoptosis of HAECs. The release of cytochrome c into cytosols markedly increased in HAECs during the treatment with gly-ox-HDL. The increased expressions of Bax and Bad were detected in HAECs incubated for 24 h with gly-ox-HDL, but gly-ox-HDL failed to interfere with the expression of Bcl-2 and Bcl-x. Moreover, in vitro experiments with HDL (gly-HDL) glycated in the presence of 2 mM EDTA and Cu(2+)-oxidized HDL suggested that the apoptotic effect of gly-ox-HDL on endothelial cells might be due to an additional oxidative modification of gly-HDL. Taken altogether, additional oxidation of HDL under hyperglycemic conditions may induce endothelial apoptosis through a mitochondrial dysfunction, following the deterioration of vascular function.


Subject(s)
Apoptosis , Endothelium, Vascular/pathology , Lipoproteins, HDL/metabolism , Mitochondria/metabolism , Proto-Oncogene Proteins c-bcl-2 , Aorta/cytology , Blotting, Western , Carrier Proteins/biosynthesis , Caspase 3 , Caspase 9 , Caspases/metabolism , Cell Nucleus/metabolism , Cells, Cultured , Cytochrome c Group/metabolism , Endothelium, Vascular/cytology , Endothelium, Vascular/metabolism , Glucose/pharmacology , Humans , Lipoproteins, HDL/pharmacology , Microscopy, Phase-Contrast , Protein Binding , Proto-Oncogene Proteins/biosynthesis , Time Factors , bcl-2-Associated X Protein , bcl-Associated Death Protein
4.
Biol Chem ; 382(6): 919-24, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11501756

ABSTRACT

Nucleotidase activities resembling subclass I and subclass II of human pyrimidine 5'-nucleotidases (P5N) were detected in chicken red blood cells (RBCs). In chicken RBCs from untreated controls, the activity of the subclass II enzyme was about one third of that of subclass I enzyme, whereas that ratio was approximately 5:1 in rat or human RBCs. The subclass I activity in chicken RBCs was increased 5- to 6-fold upon erythropoietic induction by phenylhydrazine administration, but the subclass II activity did not increase under these conditions. The subclass I enzyme was purified to near homogeneity. Its molecular mass was about 35 kDa as estimated by gel filtration and SDS-polyacrylamide gel electrophoresis. Its N-terminal 12 amino acids, PEFQKKTVHIKD, were also determined. The catalytic properties of the subclass I enzyme were very similar to those of the human enzyme with regard to substrate (preferential hydrolysis of CMP, dCMP, UMP), Km values, optimum pH, and metal ion requirements. Antibodies against chicken P5N subclass I were raised in rats. The chicken P5N-I as well as the rat P5N-I proteins could be detected by antibodies in Western blot analyses, but not the P5N-II proteins. These findings indicate that P5N subclass I may have an important function in chicken erythropoiesis.


Subject(s)
5'-Nucleotidase/isolation & purification , Chickens/blood , Erythrocytes/enzymology , 5'-Nucleotidase/classification , 5'-Nucleotidase/metabolism , Animals , Blotting, Western , Chromatography , Electrophoresis, Polyacrylamide Gel , Hydrolysis , Nucleotides/metabolism
5.
J Biochem ; 130(2): 285-93, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11481047

ABSTRACT

Peroxynitrite has been implicated in the oxidative modification of low-density lipoprotein (LDL) particles, and nitrotyrosine residues in the LDL have been detected in atherosclerotic plaques. Studies have suggested that lipoproteins modified by peroxynitrite lead to the onset of atherosclerotic vascular disease. We therefore prepared in vitro lipoproteins oxidatively modified by peroxynitrite (NO(2)-lipoprotein) and investigated the effect of NO(2)-lipoprotein on the viability of cultured endothelial cells. After exposure of a high-density lipoprotein (HDL) to peroxynitrite, some intermolecular complexes of apolipoproteins in HDL were detected on immunoblotting with monoclonal antibodies against apolipoprotein AI and AII, suggesting that nitration of HDL by peroxynitrite causes intermolecular cross-linking of the apolipoproteins in the particles. Treatment with 1 mM peroxynitrite increased the 3-nitrotyrosine level to 28.5 mmol/mol of tyrosine residues in the prepared NO(2)-HDL, as quantitated by HPLC, and the amount in NO(2)-lipoprotein depended on the peroxynitrite concentration. HDL exhibited a shorter lag phase and the reaction plateaued more rapidly than that with LDL. To clarify whether or not NO(2)-lipoproteins affect the function of endothelial cells, we first examined the viability of cultured human aortic endothelial cells (HAECs) exposed to NO(2)-lipoproteins. Incubation with either NO(2)-HDL or NO(2)-LDL significantly reduced the HAEC viability at 72 h. The results of RT-PCR and Western blotting showed that NO(2)-HDL markedly suppressed at 48 h not only the expressed levels of mRNA and protein but also the activity of catalase in HAECs. In contrast, NO(2)-LDL significantly reduced the expression and activity of Cu(2+),Zn(2+)-superoxide dismutase (CuZn-SOD) in the cells. Neither NO(2)-HDL nor NO(2)-LDL interfered with nitric oxide production or expression of cyclooxygenases and NADPH oxidase in HAECs. Increased radical production in NO(2)-lipoprotein-treated HAECs implied that reactive oxygen species such as superoxide anions and hydroxyl radicals may contribute to the mechanism of the toxic effect induced in endothelial cells by NO(2)-lipoprotein. Overall, NO(2)-lipoprotein may lead to deterioration of the vascular function through these endothelial cell responses.


Subject(s)
Cell Survival/physiology , Endothelium, Vascular/metabolism , Lipoproteins/metabolism , Peroxynitrous Acid/pharmacology , Reactive Oxygen Species/metabolism , Tyrosine/analogs & derivatives , Arteriosclerosis/metabolism , Catalase/genetics , Catalase/metabolism , Cells, Cultured , Chromatography, High Pressure Liquid , Electron Spin Resonance Spectroscopy , Endothelium, Vascular/cytology , Endothelium, Vascular/drug effects , Free Radical Scavengers/metabolism , Humans , Lipoproteins/pharmacology , Lipoproteins, HDL/metabolism , Lipoproteins, HDL/pharmacology , NADPH Oxidases/genetics , NADPH Oxidases/metabolism , Nitric Oxide/metabolism , Nitric Oxide Synthase/genetics , Nitric Oxide Synthase/metabolism , Prostaglandin-Endoperoxide Synthases/genetics , Prostaglandin-Endoperoxide Synthases/metabolism , Superoxide Dismutase/genetics , Superoxide Dismutase/metabolism , Tyrosine/analysis
6.
Clin Chim Acta ; 309(1): 73-83, 2001 Jul 05.
Article in English | MEDLINE | ID: mdl-11408008

ABSTRACT

BACKGROUND: An alpha-Amylase in human liver is detected with an anti-human salivary amylase antibody, but the enzyme activity is very low. We previously found that the rat liver contained an amylase which differed from the enzyme of mice. In this study, we characterized the human liver amylases biochemically and immunohistochermically. METHODS AND RESULTS: Although the amylase activity of human liver was much lower than that of rat, protein moiety and sugar chains of the human amylase were identified as similar to the rat liver enzyme with an anti-human salivary amylase antibody and by concanavalin A (Con A) affinity chromatography. Liver amylases from human and rat were the same size, 50 kDa, on Western blot analysis and had the same isoelectric points. The cytoplasm of hepatocytes was moderately stained immunohistochemically with the anti-human salivary amylase antibody. Intrahepatic bile ducts were also stained weak-to-moderately. RT-PCR, with a specific primer for the consensus sequence of human amylases, amplified a single 474-bp product from the human liver total RNA. The PCR product was sequenced and referred to the homology. Thirteen bases in the 434-bp fragment of the human liver amylase differed from the corresponding region of the AMY-1 gene transcript and the deduced amino acid sequence differed at five residues. The human liver amylase cDNA sequence was identical to the corresponding cDNA of the AMY-2B, which was known to expressed in tumorous tissues. In situ hybridization revealed the expression of AMY-2B mRNA in non-tumorous human liver. CONCLUSIONS: The present results suggest the possibility that a novel amylase detected in tumorous tissues and encoded by the AMY-2B gene is a liver-specific amylase expressed in the human liver.


Subject(s)
Gene Expression/genetics , Liver/enzymology , Neoplasms/enzymology , alpha-Amylases/genetics , alpha-Amylases/metabolism , Animals , Base Sequence , Bile Ducts, Intrahepatic/anatomy & histology , Bile Ducts, Intrahepatic/enzymology , Cytoplasm/enzymology , Cytoplasm/ultrastructure , DNA, Complementary/analysis , Hepatocytes/cytology , Hepatocytes/enzymology , Humans , Immunohistochemistry , In Situ Hybridization , Lung/enzymology , Molecular Sequence Data , Neoplasms/genetics , Pyrimidines/analysis , Rats , Reverse Transcriptase Polymerase Chain Reaction , Salivary Glands/enzymology , Sepharose/analogs & derivatives , Sepharose/chemistry
7.
Electrophoresis ; 22(1): 12-7, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11197159

ABSTRACT

The reactivity of rat liver alpha-amylases with maltotriose (G3), maltopentose (G5) and glycogen has been investigated. Liver amylases were found to be glycosylated and to have a molecular mass of 50 kDa by Western blotting using an anti-human salivary amylase antibody. The glycosylated liver amylases were found to be capable of G3- and G5-hydrolysis and of glucose formation, as demonstrated by thin-layer chromatography. When the amylase preparation was exposed to different concentrations of glycogen and run on a cellulose acetate membrane, the mobilities of rat liver amylases significantly decreased with tailing directly from the point of origin. In contrast, rat salivary amylases were not so much. These results indicate that rat liver amylases have a strong affinity to glycogen. We confirmed the expression of liver-specific amylases in rat liver by reverse transcriptional-polymerase chain reaction (RT-PCR); PCR products showed one band of an expected size of 474 bp using primers tested in the present study. A partial nucleotide sequence was then determined. When compared with the gene of mouse liver amylase, the substitution of 26 bases out of 434 bases was elucidated. The present data demonstrate the presence of liver-specific amylases in rats.


Subject(s)
Glycogen/metabolism , Liver/enzymology , alpha-Amylases/genetics , Animals , Base Sequence , Carbohydrates , Gene Expression , Humans , Male , Molecular Sequence Data , Molecular Weight , RNA, Messenger , Rats , Rats, Wistar , Substrate Specificity , alpha-Amylases/metabolism
8.
Metabolism ; 50(1): 3-11, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11172467

ABSTRACT

We examined the effects of a variety of ligands/activators of the peroxisome proliferator-activated receptor (PPAR) on the expression of the superoxide scavenger enzyme, Cu2+,Zn2+-superoxide dismutase (CuZn-SOD), and the superoxide generating enzyme nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH) oxidase in primary cultures of human umbilical vein endothelial cells (HUVEC) and human aorta endothelial cells (HAEC). Our data show that 3 types of PPARs, PPARalpha, PPARbeta/delta/Nuc1, and PPARgamma are expressed in endothelial cells. Bezafibrate, which is a ligand/activator for PPARalpha, increased the CuZn-SOD gene expression and protein levels in endothelial cells. Troglitazone and pioglitazone, which are ligands/activators for PPARgamma, also induced PPARalpha gene and protein expression and increased CuZn-SOD gene expression and protein levels in addition to increasing PPARgamma gene and protein expression in endothelial cells. Moreover, with treatment of monounsaturated and polyunsaturated fatty acids (PUFA), the CuZn-SOD mRNA levels were positively correlated with PPARalpha mRNA levels (r = .872, P < .0001) in primary endothelial cells. In addition, the phorbol myristate acetate (PMA)-stimulated or PMA-nonstimulated 22-kd a-subunit (p22phox) mRNA levels and 47-kd a-subunit (p47phox) protein levels in NADPH oxidase were decreased by treatment with PPARalpha and PPARgamma ligands/activators. These results suggest that PPARalpha and PPARgamma gene and protein expression in endothelial cells may play a physiologic role as radical scavengers, although the details of these mechanisms remain to be established.


Subject(s)
Endothelium, Vascular/metabolism , Membrane Transport Proteins , NADPH Dehydrogenase/biosynthesis , Phosphoproteins/biosynthesis , Receptors, Cytoplasmic and Nuclear/metabolism , Superoxide Dismutase/biosynthesis , Transcription Factors/metabolism , Cells, Cultured , Endothelium, Vascular/enzymology , Humans , Ligands , NADPH Dehydrogenase/genetics , NADPH Oxidases , Phosphoproteins/genetics , RNA, Messenger/biosynthesis , Superoxide Dismutase/genetics
9.
Comp Biochem Physiol B Biochem Mol Biol ; 126(4): 553-60, 2000 Aug.
Article in English | MEDLINE | ID: mdl-11026667

ABSTRACT

The physiological and/or clinical significance of sugar chains in human salivary alpha-amylase was investigated in terms of substrate-specificity for synthesized malto-oligosaccharides. Glycosylated and non-glycosylated alpha-amylases were prepared on a Sephacryl S-200 column, in which the amylases were separated into four fractions from the different affinities for Sephacryl: fraction I, amylases bearing sugar chains with sialic acid; fraction II, amylases bearing sugar chains without sialic acid; fractions III and IV, non-glycosylated amylases. These were classified according to the differences in their affinities for lectins, molecular sizes and isoelectric points. The inhibitory effect of maltotriose (G3) on starch hydrolysis of the amylase fraction, suggests that starch and G3 can be the substrate for glycosylated amylase, and that the glycosylated amylases are capable of G3 hydrolysis for conversion into maltose and glucose. Using malto-oligosaccharides, G3, G4, G5 and G7, as substrates, the substrate-specificities and G3/G5 ratio of amylase activities in the four fractions were examined. Maltopentaose, G5, is routinely used as a substrate for alpha-amylase, and then we assumed that both glycosylated and non-glycosylated amylases react with G5. Moreover, the results indicate that the glycosylated amylases clearly had a higher capacity for G3 hydrolysis than the non-glycosylated amylases, although no substrate preference of either type of amylase was observed among G4, G5 and G7. Glycosylated amylases have the capacity for glucose formation from malto-oligosaccharides.


Subject(s)
Glucose/metabolism , Saliva/enzymology , Trisaccharides/metabolism , alpha-Amylases/metabolism , Blotting, Western , Chromatography , Electrophoresis, Polyacrylamide Gel , Glycosylation , Humans , Hydrolysis , Neuraminidase/metabolism , Oligosaccharides/metabolism , Starch/metabolism , Substrate Specificity , alpha-Amylases/chemistry , alpha-Amylases/isolation & purification
10.
Life Sci ; 67(8): 863-76, 2000 Jul 14.
Article in English | MEDLINE | ID: mdl-10946846

ABSTRACT

We examined the effects of four 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (pravastatin, simvastatin, fluvastatin, and cerivastatin) on the production and expression of inflammatory cytokines and on enzyme expression involving prostaglandin and superoxide production in cultured human umbilical vein endothelial cells (HUVEC). All HMG-CoA reductase inhibitors significantly reduced interleukin-1beta and -6 mRNA expression and their protein levels in the culture medium, and also inhibited cyclooxygenase-2 mRNA expression and their protein levels. And these drugs induced peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma mRNA expression and their protein levels in HUVEC and hepatocyte. Moreover, the mRNA levels of p22phox, a 22-kD subunit and the protein levels of p47phox, a 47-kD subunit of nicotine adenine dinucleotide phosphate (NADPH) oxidase, was decreased by treatment with either simvastatin, fluvastatin or cerivastatin, and this effect was reversed by mevalonate, geranylgeraniol, farnesol, and cholesterol. The changes induced by HMG-CoA reductase inhibitors might be due to regulation of cellular cholesterol content level, cellular cholesterol metabolic pathway, and cellular PPARalpha activity, which was related with inflammation. This unique anti-inflammatory effect in addition to its hypolipidemic action, may be beneficial in preventing the vascular complications that are induced by hyperlipidemia.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Endothelium, Vascular/drug effects , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Interleukin-1/genetics , Interleukin-6/genetics , Isoenzymes/genetics , Membrane Transport Proteins , NADPH Dehydrogenase/genetics , Phosphoproteins/genetics , Prostaglandin-Endoperoxide Synthases/genetics , RNA, Messenger/analysis , Receptors, Cytoplasmic and Nuclear/physiology , Transcription Factors/physiology , Cells, Cultured , Cyclooxygenase 2 , Endothelium, Vascular/cytology , Endothelium, Vascular/metabolism , Gene Expression Regulation/drug effects , Humans , Membrane Proteins , NADPH Oxidases
11.
Ann Clin Biochem ; 37 ( Pt 2): 179-86, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10735361

ABSTRACT

We examined the localization of oxidized high-density lipoprotein (HDL) in atheromatous plaques and the oxidized HDL binding sites on endothelial cells. Histochemical analysis using CuSO4-oxidized HDL-specific 9F5-3a antibody indicated the presence of oxidized HDL in the intima of atheromatous plaques in human abdominal aortae. The cell surface binding of 125I-oxidized HDL to cultured human aortic endothelial cells (HAEC) was saturable, with an apparent dissociation constant (Kd) of 1.43 micromol/L. Competition for 125I-oxidized HDL binding was strong for oxidized HDL, moderate for native HDL and low for acetylated low-density lipoprotein (LDL) or oxidized LDL. Using oxidized HDL as a ligand for blotting, a major 130-kDa band was detected in HAEC. These results suggest that oxidized HDL and its putative binding protein are present in atheromatous plaques and endothelial cells, respectively.


Subject(s)
Aorta/metabolism , Arteriosclerosis/metabolism , Lipoproteins, HDL/metabolism , Antibodies, Monoclonal/metabolism , Binding Sites , Binding, Competitive , Blotting, Western , Cells, Cultured , Endothelium, Vascular/metabolism , Humans , Immunohistochemistry , Iodine Radioisotopes , Kinetics , Lipoproteins, HDL/analysis , Lipoproteins, HDL/immunology , Membrane Proteins/analysis , Oxidation-Reduction , Protein Binding
12.
Anat Rec ; 258(2): 119-27, 2000 02 01.
Article in English | MEDLINE | ID: mdl-10645959

ABSTRACT

Endothelial-mesenchymal transformation (EMT) is a critical event in the generation of the endocardial cushion, the primordia of the valves and septa of the adult heart. This embryonic phenomenon occurs in the outflow tract (OT) and atrioventricular (AV) canal of the embryonic heart in a spatiotemporally restricted manner, and is initiated by putative myocardially derived inductive signals (adherons) which are transferred to the endocardium across the cardiac jelly. Abnormal development of endocardial cushion tissue is linked to many congenital heart diseases. At the onset of EMT in chick cardiogenesis, transforming growth factor (TGFbeta)-3 is expressed in transforming endothelial and invading mesenchymal cells, while bone morphogenetic protein (BMP)-2 is expressed in the subjacent myocardium. Three-dimensional collagen gel culture experiments of the AV endocardium show that 1) myocardially derived inductive signals upregulate the expression of AV endothelial TGFbeta3 at the onset of EMT, 2) TGFbeta3 needs to be expressed by these endothelial cells to trigger the initial phenotypic changes of EMT, and 3) myocardial BMP2 acts synergistically with TGFbeta3 in the initiation of EMT.


Subject(s)
Bone Morphogenetic Proteins/physiology , Endothelium, Vascular/embryology , Heart/embryology , Mesoderm/physiology , Transforming Growth Factor beta/physiology , Animals , Endocardium/embryology
13.
Nihon Rinsho ; 57 Suppl: 133-5, 1999 Aug.
Article in Japanese | MEDLINE | ID: mdl-10503379
14.
Biochem Biophys Res Commun ; 260(3): 813-9, 1999 Jul 14.
Article in English | MEDLINE | ID: mdl-10403847

ABSTRACT

It has been suggested the the interaction of Escherichia coli O157-derived verotoxins (VTs) with the vascular endothelium plays a central role in the pathogenesis of the thrombotic microangiopathy and ischemic lesions characteristic of hemolytic uremic syndrome (HUS) and E. coli O157-associated hemorrhagic colitis. Intravenous administration of both E. coli O157-derived VT1 and lipopolysaccharide (LPS) in the rat induced a synergistic increase in thiobarbituric acid (TBA) values in those animal's plasma, as compared with that injected with VT1 or LPS alone. We then hypothesized that an increase in lipid peroxidation in the rat plasma was due to an enhanced production of endothelial cell-derived reactive oxidant. Based on determination of rat sera and cultured human aortic endothelial cells (HAECs), VT1 had little if any effect on LPS-stimulated increase of nitric oxide and the resultant peroxynitrite generations. Both RT-PCR and Western blot studies of reactive oxygen species-related enzymes showed that VT1 markedly decreased the expression of catalase mRNA and protein in HAECs, but caused less alteration in the levels of Cu, Zn-superoxide dismutase, and NADPH oxidase mRNA. Further studies by spin trapping analysis using 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO) revealed a time-dependent increase in hydroxyl radicals by VT1 in HAECs. The accumulated data thus suggest that bacterial VT1 reduces mainly catalase levels in endothelial cells, which is synergistically potentiated by LPS, and that the resulting hydroxyl radical participates in endothelium injury through a marked enhancement of lipid peroxidation, leading to HUS.


Subject(s)
Bacterial Toxins/toxicity , Endothelium, Vascular/metabolism , Reactive Oxygen Species/metabolism , Animals , Aorta , Bacterial Toxins/administration & dosage , Catalase/genetics , Catalase/metabolism , Cell Survival/drug effects , Cells, Cultured , Drug Synergism , Endothelium, Vascular/cytology , Endothelium, Vascular/drug effects , Escherichia coli O157 , Hemolytic-Uremic Syndrome/metabolism , Humans , Hydroxyl Radical/metabolism , Lipid Peroxidation/drug effects , Lipopolysaccharides/administration & dosage , Lipopolysaccharides/pharmacology , Male , Nitrates/metabolism , Nitric Oxide/metabolism , Oxidoreductases/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Wistar , Risk Factors , Shiga Toxin 1 , Thiobarbituric Acid Reactive Substances/analysis
15.
Rinsho Byori ; 47(4): 370-3, 1999 Apr.
Article in Japanese | MEDLINE | ID: mdl-10340012

ABSTRACT

NO-related compounds in the blood of septic rats were examined by chemiluminescence method. Rats were treated with 5 mg/kg or 10 mg/kg lipopolysaccharides (LPS) and followed for 30 h. We have determined and evaluated the concentrations of the total NO-related compounds in whole blood (Total-NO), those in plasma (Plasma-NO) and membrane bound-NO (Membranous-NO) in erythrocytes from the LPS-challenged rats. 1) Levels of Plasma-NO after 3 h and Membranous-NO after 7 h in the rats were significantly increased, peaked at 14 h, and then restored to control levels at 30 h. 2) At 7 h in the rats, latter NO levels were exhibited within 10 nM/mg protein. 3) The existence of Membranous-NO can be confirmed by the in vitro experiments of rat erythrocytes incubating with different NO-donors, NOC-3 or SIN-1. 4) Taken together, the determination of Membranous-NO may be an additional marker for pathophysiological states of septic stress.


Subject(s)
Endotoxemia/blood , Nitric Oxide/blood , Animals , Erythrocyte Membrane/chemistry , Male , Rats
16.
Clin Chim Acta ; 275(1): 27-41, 1998 Jul 06.
Article in English | MEDLINE | ID: mdl-9706841

ABSTRACT

The lower levels of serum alkaline phosphatase (AP) activity found in patients with diabetes mellitus apparently originate from the selective disappearance or decrease in bone AP activity in the circulation. Hence, we investigated in vitro the effect of glycation on the activities of five AP isozymes. Aseptic incubation with 25 mmol/L of D-glucose and APs rapidly reduced bone and placental AP activities before those of liver, kidney and intestinal enzymes. The resulting bone and placental AP molecules were clearly glycated, according to the result of aminophenylboronic acid affinity chromatography. Furthermore, Western blotting analysis revealed that the placental AP molecule was fragmented, and its partial cleavage took place at Ala154 on the AP molecule. Since glycation of serum proteins causes the generation of reactive oxygen species, the effects of reactive oxygen species on placental AP activity were assayed, and the results indicated that hydroxyl radicals might be a major factor for the specific inactivation of AP activities. The reduction in AP activity by incubation with glucose in vitro was reversed by the further addition of catalase. Furthermore, ferrous ion with hydrogen peroxide, which generates hydroxyl radicals, had an inhibitory effect on AP activities. These findings suggest that the reduced AP activity in diabetic patients might result from partial cleavage of the bone AP molecule by reactive oxygen species induced by glycation.


Subject(s)
Alkaline Phosphatase/metabolism , Glucose/metabolism , Isoenzymes/metabolism , Reactive Oxygen Species/metabolism , Alkaline Phosphatase/chemistry , Blotting, Western , Bone and Bones/enzymology , Boronic Acids , Chromatography, Affinity , Chromatography, High Pressure Liquid , Duodenum/enzymology , Electron Spin Resonance Spectroscopy , Free Radical Scavengers/pharmacology , Glucose/chemistry , Humans , Isoenzymes/chemistry , Kidney/enzymology , Liver/enzymology , Oxidation-Reduction , Placenta/enzymology
17.
Biol Chem ; 379(3): 329-33, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9563829

ABSTRACT

A nucleotidase that catalyzed selective hydrolysis of pyrimidine 5'-nucleotides was investigated in rat red blood cells (RBCs). The enzyme had similar catalytic properties to human pyrimidine 5'-nucleotidase I (P5N-I). The P5N-I deficiency was known to be closely correlated with the human inherited disease, non-spherocytic hemolytic anemia. Similar to the human P5N-I, the rat enzyme preferentially hydrolyzed 5'-(d)CMP and 5'-UMP but no reactivity was observed with any 3'-nucleotide. Molecular mass of the enzyme was estimated to be approximately 38 kDa by gel filtration and SDS-polyacrylamide gel electrophoresis. Another subclass of pyrimidine 5'-nucleotidase, P5N-II, was also present in rat RBCs. This P5N-II-like enzyme, which resembled a 5'(3')-nucleotidase, preferentially hydrolyzed both 5'- and 3'- of (d)TMP or (d)UMP, but no cytosine nucleotide was hydrolyzed by the enzyme. Results from the reactivity with the antibody against rat 5'(3')-nucleotidase and estimated subunit molecular mass of the enzymes, about 26 kDa, suggested that the P5N-II-like enzyme had a similar structure to the 5'(3')-nucleotidase. The P5N-I-like activity in rat RBCs increased 5 to 6-fold at 4 days after phenylhydrazine injection, and reached a maximum at 6 to 7 days. No change in the activity of P5N-II-like nucleotidase was observed during the experimental period. The increase in rat P5N-I activity coincided with maturation of the erythrocytes.


Subject(s)
5'-Nucleotidase/blood , Erythrocytes/enzymology , Erythropoiesis , Animals , Cytidine Monophosphate/metabolism , Humans , Hydrolysis , Male , Molecular Weight , Rats , Rats, Wistar , Spleen/physiology , Substrate Specificity
18.
Comp Biochem Physiol B Biochem Mol Biol ; 121(4): 417-23, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9972313

ABSTRACT

We found previously that human bone alkaline phosphatase (AP) was glycated by aseptic incubation with glucose, and partially broken down by reactive oxygen species. In this study, we examined whether selective in vivo glycation of AP molecules occurred in bone tissue, using experimental diabetic rats induced by streptozotocin and spontaneously diabetic rats. Additionally, the effects of hyperlipidemia on bone AP activity were examined. Serum AP activity was significantly elevated after incipient onset of diabetes, and the increased activity originated from the intestinal isozyme. High levels of intestinal AP activity were also observed in rats with hyperlipidemia induced by feeding high-fat or high-fructose chow, but the AP activity in bone tissues was maintained at a constant level. AP activity in bone was reduced after the onset of diabetes. The resulting bone AP molecule bound to an aminophenylboronic acid column, which had affinity for glycated proteins, and contained smaller molecular sizes than the native bone AP. These results suggest that elevated levels of serum AP activity originated from the intestinal isozyme accompanied with hyperlipidemia induced by diabetes. In contrast, the reduced serum levels of AP activity in diabetic rats might be dependent on inactivation of bone AP, which was glycated, followed by partial breakdown of bone AP molecules, possibly due to reactive oxygen species.


Subject(s)
Alkaline Phosphatase/metabolism , Bone and Bones/enzymology , Diabetes Mellitus, Experimental/enzymology , Diabetes Mellitus, Type 1/enzymology , Alkaline Phosphatase/blood , Alkaline Phosphatase/chemistry , Animals , Diabetes Mellitus, Experimental/complications , Diabetes Mellitus, Type 1/complications , Glycosylation , Humans , Hyperlipidemias/complications , Hyperlipidemias/enzymology , Intestines/enzymology , Isoenzymes/chemistry , Isoenzymes/metabolism , Male , Molecular Weight , Organ Culture Techniques , Rats , Rats, Inbred BB , Rats, Wistar , Reactive Oxygen Species/metabolism , Tissue Distribution
19.
Biochem Mol Biol Int ; 37(3): 583-90, 1995 Oct.
Article in English | MEDLINE | ID: mdl-8595399

ABSTRACT

Deoxyuridine triphosphatase (dUTPase) activity increases concomitantly with DNA replication in the course of liver regeneration in rat. We confirmed in this report using Western blot analysis and Northern blot hybridization that the increase of dUTPase activity was derived from expression of the gene. The content of dUTPase protein quantitatively coincided with the activity, they reached to the maximum at about 24 h after partial hepatectomy. We also detected a transcript (1.0 kb) presumed to be a rat spleen dUTPase mRNA by the human dUTPase cDNA probe. This transcript appeared in the liver after a lag of about 16 h, reached to the maximum at 24 h, and could be detected until 48 h after partial hepatectomy. The increase of this transcript nearly coincided with the changes of dUTPase activity and the quantity of enzyme protein. These results indicated that the expression of dUTPase gene is related to the DNA replication.


Subject(s)
DNA Replication , DNA, Complementary , Liver Regeneration/physiology , Pyrophosphatases/biosynthesis , Animals , Hepatectomy , Humans , Male , Rats , Rats, Wistar , Spleen/enzymology
20.
Kansenshogaku Zasshi ; 68(6): 734-9, 1994 Jun.
Article in Japanese | MEDLINE | ID: mdl-8051439

ABSTRACT

Between October, 1992 and March, 1993, the incidence of bite or scratch by the cat, was surveyed by questionnaire in 1,619 peoples who were veterinarians, veterinary technicians, students and the general population (male 652, female 967). The wound rate by cat: Veterinarians, veterinary technicians, students of veterinary college, students of veterinary technician school were significantly higher than the general population. Incidence of bite or scratch in the cat owner were significantly higher than the non cat owner, and the incidence of wounds in cat owners was more than 90%. Most injuries for veterinarians were of the occupational nature. Their injuries clearly differed from those of the other groups. In our survey 33 cases were suspected to have CSD; 19 of 102 veterinarians, 4 of 45 veterinary technicians, 2 of 517 students of veterinary college, 1 of 400 students of veterinary technicians, 7 of 555 in the general population. Of the seven cases suspected for CSD among the general population, four were proven to have cat-scratches, suggesting that injuries can be prevented by clipping the cat's nails at home. However, most of the injuries suffered by veterinarians are caused by bites, prevention poses a more serious problem. It is therefore important to educate people in all fields to fully understand sanitation and zoonosis including CSD, and teach them to handle their pets appropriately.


Subject(s)
Bites and Stings/epidemiology , Cat-Scratch Disease/epidemiology , Cats , Skin/injuries , Adolescent , Adult , Animals , Child , Child, Preschool , Female , Humans , Incidence , Infant , Male , Middle Aged
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