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Biomedical subjects

M Takagi

Publications and source records attributed to M Takagi.

At least 325 records · Page 18Linked to original sources
PubMed1998

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in loose artificial hip joints.

The role of extracellular matrix metalloproteinase enzymes and the tissue inhibitors of metalloproteinase in the periprostetic connective tissue matrix of loose artificial hip joints is reviewed. In the periprosthetic granulomatous interface connective tissues between bone and implants and inner cellular regenerating pseudocapsular tissues, matrix metalloproteinase 1, matrix metalloproteinase 2, matrix metalloproteinase 3, matrix metalloproteinase-9, and membrane type 1 matrix metalloproteinase enzymes can be shown in the light of immunohistochemistry, enzyme activity analysis, and messenger ribonucleic acid levels. Tissue inhibitors of metalloproteinase 1 and tissue inhibitors of metalloproteinase 2 also are found in the corresponding tissues. Analysis of matrix metalloproteinase and tissue inhibitors of metalloproteinase interaction shows imbalance between the enzymes and the endogenous inhibitors in favor of matrix metalloproteinase. This induces pathologic connective tissue remodeling in the interface and pseudocapsule. The data suggest that matrix metalloproteinase and tissue inhibitors of metalloproteinase system participate in the extracellular matrix degradation and tissue remodeling in artificial hip joints, and may contribute to the periprosthetic weakening, implant loosening, and osteolysis around implants. More evidence for their active involvement is sought by intervention studies with type specific matrix metalloproteinase inhibitors.

Animals↗
PubMed1998

[Giant cell arteritis with bilateral obstruction of the internal carotid artery--report of an autopsy case].

Internal carotid artery involvement and dementia occur infrequently in patients with giant cell (temporal) arteritis. A 75-year-old woman admitted with progressive cognitive decline, drowsiness and headache was diagnosed as having giant cell arteritis by temporal artery biopsy (TAB). High dose corticosteroid improved inflammatory reaction but did not improve his cognitive function. Cerebral angiograms showed obstruction of both internal carotid arteries at the siphon. Brain MRI showed only small cerebral infarcts in the basal ganglia and corona radiata bilaterally. However, brain SPECT disclosed reduced cerebral blood flow in the frontal lobe bilaterally. A postmortem examination revealed bilateral parietal infarcts and isolated giant cell arteritis involving the both internal carotid arteries at the siphon. We speculated that perfusion insufficiency and multiple cerebral infarction due to bilateral internal carotid artery occlusion had caused this neurologic deterioration.

Aged↗
PubMed1998

Matrix metalloproteinase-mediated extracellular matrix protein degradation in human pulmonary emphysema.

The aim of this study was to investigate the extracellular degrading proteolytic cascade proteins referred to as matrix metalloproteinase-1 (MMP-1), MMP-2, MMP-9, membrane-type matrix metalloproteinase-1 (MT1-MMP), tissue inhibitors of matrix metalloproteinase-1 (TIMP-1), TIMP-2, neutrophil elastase, and alpha1-antitrypsin in human pulmonary emphysema. Localization of MMP-1, MMP-2, MMP-8, MMP-9, MT1-MMP, TIMP-1, and TIMP-2 was verified by immunohistochemical analysis. The results of our study indicated that the immunoreactivity of MMP-1, MMP-8, MMP-9, and TIMP-1 was absent, whereas MT1-MMP and MMP-2 were mainly observed in pneumocytes, fibroblasts, and alveolar macrophages. Although MT1-MMP and MMP-2 were observed both in emphysematous and normal lung tissue, these immunoreactivities were intense in the emphysematous samples. The presence of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 was confirmed at mRNA level by reverse transcription-PCR analysis and enzyme immunoassay (EIA). However, the only statistical difference that was observed was in MMP-2 and MMP-9 (MMP-2: emphysematous samples, 19.1+/-2.1 versus control samples, 5.2+/-0.60 microg/g protein, p < 0.05; MMP-9: emphysematous samples, 18.4+/-5.6 versus control samples, 8.1+/-2.7 microg/g protein, p < 0.05). Results of the neutrophil elastase as analyzed by EIA, and alpha1-antitrypsin levels as detected by laser nephelometric immunoassay, indicated no statistical difference between the emphysematous and control groups. In addition to the presence of mRNA levels, the level of MT1-MMP according to immunoblot analysis increased in the emphysematous samples. Gelatin zymographic analysis confirmed the presence of both pro and active forms of MMP-2, and the increased ratio of the active form of MMP-2 in emphysematous samples (25.9%+/-2.0% versus 11.2%+/-3.3%, p < 0.05), indicated in situ activation of MMP-2 by MT1-MMP. Elastin zymographic analysis showed elastolytic activity by MMP-2 and MMP-9 but not the reported band of macrophage metalloelastase (MMP-12). The data suggest that the MT1-MMP/MMP-2/TIMP-2 system plays a significant role in the MMP-mediated extracellular matrix degradation and tissue remodeling of emphysematous lungs, and thus may contribute to the weakening of lung parenchyma and lead to the formation of emphysema.

Aged↗
PubMed1998

Relation between the kinetics of thallium-201 in myocardial scintigraphy and myocardial metabolism in patients with acute myocardial infarction.

OBJECTIVE: To investigate the relations between myocardial metabolism and the kinetics of thallium-201 in myocardial scintigraphy. METHODS: 46 patients within six weeks after the onset of acute myocardial infarction underwent resting myocardial dual isotope, single acquisition, single photon emission computed tomography (SPECT) using radioiodinated 15-iodophenyl 3-methyl pentadecaenoic acid (BMIPP) and thallium-201, exercise thallium-201 SPECT, and positron emission tomography (PET) using nitrogen-13 ammonia (NH3) and [F18]fluorodeoxyglucose (FDG) under fasting conditions. The left ventricle was divided into nine segments, and the severity of defects was assessed visually. RESULTS: In the resting SPECT, less BMIPP uptake than thallium-201 uptake was observed in all of 40 segments with reverse redistribution of thallium-201, and in 21 of 88 segments with a fixed defect of thallium-201 (p < 0.0001); and more FDG uptake than NH3 uptake (NH3-FDG mismatch) was observed in 35 of 40 segments with reverse redistribution and in 38 of 88 segments with fixed defect (p < 0.0001). Less BMIPP uptake in the resting SPECT was observed in 49 of 54 segments with slow stress redistribution in exercise SPECT, and in nine of 17 segments with rapid stress redistribution (p < 0.0005); NH3-FDG mismatch was observed in 42 of 54 segments with slow stress redistribution and in five of 17 segments with rapid stress redistribution (p < 0.0005). CONCLUSIONS: Thallium-201 myocardial scintigraphy provides information about not only myocardial perfusion and viability but also about myocardial metabolism in patients with acute myocardial infarction.

Adult↗
PubMed1998

Expression of stem cell factor (SCF) and SCF receptor (c-kit) in synovial membrane in arthritis: correlation with synovial mast cell hyperplasia and inflammation.

OBJECTIVE: Stem cell factor (SCF), the ligand for the SCF receptor (c-kit) expressed on precursors and mature mast cells (MC), is a major agonist for human MC (e.g., SCF induces MC development, chemotaxis, activation, proliferation of MC precursors, mediates MC adhesion, and changes MC releasability). We investigated expression of SCF and c-kit in synovial membrane with particular reference to the mechanism of local MC hyperplasia and inflammation in arthritis. METHODS: We conducted single and double labeling immunohistochemistry (ABC, APAAP, indirect immunofluorescence techniques) with antibodies to SCF, c-kit, MC tryptase, Ki-67 antigen (marker for proliferating cells), and CD68 (monocyte/macrophage marker). Synovial specimens analyzed were from 31 patients: traumatic arthritis (TrA, n=9), osteoarthritis (OA, n=12), and rheumatoid arthritis (RA, n=10). Control experiments were performed on human lung, skin, and buccal mucosa tissues, on the HMC-1 mast cell line, and isolated lung MC. Morphometry was performed by computerized image analysis. RESULTS: Synovial c-kit expression was found to be restricted to MC, whereas SCF is detected in synovial lining cells, stromal fibroblasts, monocyte/macrophages, endothelial cells, and in vascular basement membranes. SCF staining was localized to MC as well, but it was not possible to specify whether this represents SCF produced by or bound (via c-kit) to MC. In inflamed synovial membranes/areas, SCF was found to be redistributed into the extracellular matrix. Redistribution of SCF was accompanied by degranulation and/or accumulation of c-kit+ MC, the hyperplasia of which correlated positively with histologic inflammation/inflammatory cell densities, but did not appear to involve MC proliferation in situ. These findings appeared to be common for all the conditions (TrA, OA, RA) studied. CONCLUSION: In addition to the demonstration/characterization of SCF and c-kit protein expression in human synovium, results of this study suggest the hypothesis that, in arthritis, local mobilization of SCF may play a role in the development of synovial MC hyperplasia without inducing in situ proliferation of MC, and that the synovial SCF/MC c-kit system may contribute to the local nonspecific inflammatory response/arthritic flares in TrA, OA, and RA.

Adult↗
PubMed1998

Coronary revascularization and abdominal aortic aneurysm repair in a patient with Behçet's diseases.

Behçet's disease is a systemic disease characterized by oral aphta, genital ulcer, and ocular lesion. Arterial involvement is an uncommon complication of Behçet's disease, and it most frequently affects the abdominal aorta followed by the femoral artery and the pulmonary artery. Coronary lesions in Behçet's disease have been little reported in the literature. In this communication, we present a case with coronary artery stenosis and with subsequently developed supra-renal abdominal aortic aneurysm. The coronary lesions were revasculized with gastroepiploic artery, right internal mammary artery, and saphenous vein graft. Abdominal aortic repair was performed with partial cardiopulmonary stand by, because of the risk of coronary ischemia during the cross clamp including the celiac artery. To our knowledge, this is the first report of successful repair of combined lesions of the coronary and the abdominal aorta in a patient with Behçet's disease.

Aortic Aneurysm, Abdominal↗
PubMed1997

Effect of heat treatment on proper oligomeric structure formation of thermostable glutamate dehydrogenase from a hyperthermophilic archaeon.

Natural glutamate dehydrogenase (Pk-GDH) was purified from hyperthermophilic archaeon Pyrococcus sp. KOD1 to homogeneity and its activity and structure were compared with those of recombinant enzyme, which was expressed in Escherichia coli. Determination of the molecular weight of these enzymes by SDS-PAGE and gel filtration revealed that the natural enzyme was purified only as a hexameric form, whereas the recombinant enzyme was purified as both monomeric and hexameric forms. Determination of the enzymatic activities indicated that only the enzyme in a hexameric form is active. Moreover, it is noted that the specific activity of the hexameric form of the recombinant enzyme is much lower than that of the natural enzyme and that circular dichroism spectra of these enzymes are distinctly different from each other. These results suggest that the structure of the hexameric form of the recombinant enzyme with low specific activity (Type I) is different from that of the natural enzyme with high specific activity (Type II). Upon heat treatment (80 degrees C, 15 min), the Type I structure was effectively converted to Type II structure and the specific activity of the enzyme was increased by 2.6-fold. Likewise, upon heat treatment (70 degrees C for 15 min), the inactive monomeric form of the recombinant enzyme was at least partially associated with the hexameric form. These results indicate that high temperature plays an important role for proper folding and oligomerization of Pk-GDH.

Archaeal Proteins↗
PubMed1997

Detection of serum antibodies against phosphocholine-containing aminoglycoglycerolipid specific to Mycoplasma fermentans in HIV-1 infected individuals.

Mycoplasma fermentans has been associated with acquired immunodeficiency syndrome (AIDS). The lipids extracted from five strains of M. fermentans and eight other species of mycoplasmas were investigated. By using high-performance thin-layer chromatography (HPTLC) and immunostaining on HPTLC-plates with polyclonal and monoclonal antibodies against lipids of M. fermentans, a glycophospholipid GGPL-III was proved to be a specific lipid and important antigen of the species of M. fermentans. Previously we reported that M. fermentans had phosphocholine-containing glycoglycerolipid (GGPL-I and GGPL-III). TLC immunostaining showed that anti-GGPL-III specific antibodies were detected in HIV-1 infected individuals. By employing purified GGPL-III, an enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of specific antibodies to GGPL-III in human serum. This ELISA showed high sensitivity, specificity and good reproducibility. Frequency of antibodies to GGPL-III was significantly higher in sera from HIV-1 infected people (44.6%, 29/65) than from HIV-1 negative healthy donors (1.7%, 2/117) or patients with three kinds of other diseases we investigated (0-8.7%, 0/20-2/23). Thus M. fermentans infection seemed to be correlated with HIV-1 infection although further investigation is essential for clarification of the role of M. fermentans during the long latency period in HIV infected individuals.

Antibodies, Bacterial↗
PubMed1997

Accumulation of misfolded protein aggregates leads to the formation of russell body-like dilated endoplasmic reticulum in yeast.

RNAP-1, an aspartic proteinase from a filamentous fungus Rhizopus niveus, is secreted very efficiently in Saccharomyces cerevisiae. It is synthesized first as a precursor form with signal sequence and prosequence in its amino-terminus. Our previous study indicated that the prosequence of RNAP-I had important roles in its correct folding and secretion in yeast, and that a prosequence-deleted derivative of RNAP-I, delta pro, was not secreted but was retained and degraded in the yeast endoplasmic reticulum (ER). In the present study, we show that the accumulation of delta pro in the yeast ER caused elevated synthesis of ER resident chaperones, indicating that delta pro is recognized as an unfolded protein species in the ER. Our biochemical data demonstrated that delta pro formed aggregates which contained BiP, but not protein disulfide isomerase (PDI), in the ER. Immunoelectron microscopical analysis revealed that the delta pro aggregates were indeed visible as electron-dense regions in the ER and nuclear envelope. Such 'chaperone-associated misfolded protein bodies' were observed for the first time in yeast. Morphologies of the ER and nucleus were drastically altered by the accumulation of the delta pro aggregates. The ER lost its flat cisternal shape; the ER lumen extended aberrantly and the ER membrane irregularly proliferated. The misfolded delta pro proteins are probably sorted from the ordinary ER lumen to form the aggregates so that the ER function would not be grossly impaired, and the dilated ER may represent an ER subcompartment where the delta pro aggregates are degraded.

Amino Acid Sequence↗
PubMed1997

A novel fungal gene encoding chitin synthase with a myosin motor-like domain.

A csmA gene that encodes chitin synthase with a myosin motor-like domain was isolated from the filamentous fungus Aspergillus nidulans. Initially, we obtained the csmA as a homolog of the Aspergillus fumigatus chsE-partial fragment. A large open reading frame encoding a polypeptide of 1,852 a.a. was identified by determining the cDNA sequences. The chitin synthase conserved region was situated at the C-terminus and classified into class V as reported previously. On the other hand, the N-terminal region showed significant similarity to myosin motors and could not be classified into any types of myosins identified so far. Thus, it is suggested that this is the first report of unconventional myosin fused to a metabolic enzyme. The finding of this new type of chitin synthase gene suggests that localization of chitin synthesis may be guided by association with cytoskeletal structures.

Amino Acid Sequence↗
PubMed1997

Identification of a chick homologue of Fringe and C-Fringe 1: involvement in the neurogenesis and the somitogenesis.

In Drosophila, Serrate plays an important role to the wing margin formation. A putative secretory protein, Fringe, is indispensable for the wing margin formation inducing Serrate and other genes. Recently, Xenopus homologues of Fringe were identified and one of them, lunatic Fringe (X-lFng), was demonstrated to be involved in mesoderm induction. We have identified two chick Fringe homologous genes by reverse transcription-polymerase chain reaction and cDNA library screening. One of them, C-Fringe 1, showed sequence similarity to X-lFng. In situ hybridization study of C-Fringe 1 has demonstrated its expression in the developing nervous system and in the presomitic mesoderm. The hindbrain and spinal cord showed the distinct stripe pattern expression which was complementary to that of C-Serrate, indicating the correlation between them in vertebrate.

Amino Acid Sequence↗
PubMed1997

DNA damage-associated dysregulation of the cell cycle and apoptosis control in cells with germ-line p53 mutation.

Lymphoblastoid cell lines (LCLs) with heterozygous p53 mutations at residues 286A, 133R, 282W, 132E, and 213ter were established from five independent Li-Fraumeni syndrome families. When cell cycle regulation in response to gamma-irradiation was studied, these LCLs showed an abnormal G1 checkpoint associated with defective inhibition of cyclin E/cyclin-dependent kinase 2 activity in all cases except for 282W LCL, which showed a normal G1 checkpoint. On the other hand, the control of S-phase-G2 as determined by cyclin A/cyclin-dependent kinase 2 activity was defective in all these LCLs. The mitotic checkpoint was also defective in the two LCLs analyzed as either competent or incompetent for G1 arrest. When radiation-induced apoptosis, which requires wild-type p53 function under optimal conditions, was studied, all of these LCLs showed significant failure compared to normal LCLs. These findings indicate that although p53-dependent transactivation and G1-S-phase cell cycle control are variably dysregulated, the induction of apoptosis and control of the cell cycle at S-phase-G2 and the mitotic checkpoint in response to DNA-damaging agents are consistently dysregulated in heterozygous mutant LCLs. This suggests that these dysfunctions underlie, at least in part, the susceptibility of Li-Fraumeni syndrome families to cancer. Furthermore, the approach presented is a potentially useful method for studying individual carriers of different germ-line p53 mutations and different biological features.

Adolescent↗
PubMed1997

Evaluation of antioxidant activity by chemiluminescence.

A sensitive and simple chemiluminescent method for measuring antioxidant activity was developed. The method is based on antioxidant-dependent quenching of chemiluminescence generated from lipid hydroperoxide and isoluminol/microperoxidase reagent. This method was used to evaluate the antioxidant ability of various antioxidants by measuring the half-inhibition concentration (IC50). The results were compared to those measured with an oxygen electrode method. They were approximately similar in pattern and level, although there was some discrepancy, which was assumed to be due to a possible difference in the reaction mechanisms of the two methods. This method also suggested an additive property of antioxidant activity with different antioxidants. Thus, the present method was used to evaluate the total antioxidant activity in biological tissues such as rat serum, human saliva, and green tea.

Animals↗
PubMed1997

Properties of yeast expressed Aspergillus nidulans chitin synthase B which is essential for hyphal growth.

A complementary DNA of the Aspergillus nidulans chsB gene encoding chitin synthase, an essential gene for hyphal growth, was obtained by RT-PCR and expressed in Saccharomyces cerevisiae by using the GAL1 promoter in a multicopy plasmid. The biochemical characteristics of chitin synthase B (ChsB) expressed in S. cerevisiae were examined. The chitin synthase B produced in galactose medium showed zymogenicity due to activation by trypsin treatment and required Mg2+ ion to exert maximal activity. It was competitively inhibited by polyoxin D. The Ki value of the inhibitor was 10 microM, and the K(m) for the substrate was 1.6 mM. The activity was enhanced by the addition of N-acetylglucosamine. The optimal pH is 7.5 when Mg2+ is used. These characteristics are the same as those of other chitin synthases.

Aspergillus nidulans↗
PubMed1997

The Aspergillus nidulans genes chsA and chsD encode chitin synthases which have redundant functions in conidia formation [corrected and republished article originally appeared in Mol Gen Genet 1996 Jun; 251(4):442-50].

We previously isolated three chitin synthase genes (chsA, chsB, and chsC) from Aspergillus nidulans. In the present work, we describe the isolation and characterization of another chitin synthase gene, named chsD, from A. nidulans. Its deduced amino acid sequence shows 56.7% and 55.9% amino acid identity, respectively, with Cal1 of Saccharomyces cerevisiae and Chs3 of Candida albicans. Disruption of chsD caused no defect in cell growth or morphology during the asexual cycle and caused no decrease in chitin content in hyphae. However, double disruption of chsA and chsD caused a remarkable decrease in the efficiency of conidia formation, while double disruption of chsC and chsD caused no defect. Thus it appears that chsA and chsD serve redundant functions in conidia formation.

Amino Acid Sequence↗
PubMed1997

Induction of apoptosis by ASK1, a mammalian MAPKKK that activates SAPK/JNK and p38 signaling pathways.

Mitogen-activated protein (MAP) kinase cascades are activated in response to various extracellular stimuli, including growth factors and environmental stresses. A MAP kinase kinase kinase (MAPKKK), termed ASK1, was identified that activated two different subgroups of MAP kinase kinases (MAPKK), SEK1 (or MKK4) and MKK3/MAPKK6 (or MKK6), which in turn activated stress-activated protein kinase (SAPK, also known as JNK; c-Jun amino-terminal kinase) and p38 subgroups of MAP kinases, respectively. Overexpression of ASK1 induced apoptotic cell death, and ASK1 was activated in cells treated with tumor necrosis factor-alpha (TNF-alpha). Moreover, TNF-alpha-induced apoptosis was inhibited by a catalytically inactive form of ASK1. ASK1 may be a key element in the mechanism of stress- and cytokine-induced apoptosis.

Amino Acid Sequence↗