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Biomedical subjects

K Oda

Publications and source records attributed to K Oda.

At least 19 recordsLinked to original sources
PubMed1998

Mechanism of angiotensin II-mediated regulation of fibronectin gene in rat vascular smooth muscle cells.

This study was performed to investigate a mechanism of angiotensin II (Ang II)-mediated activation of the fibronectin (FN) gene in rat vascular smooth muscle cells. Actinomycin D and CV11974 completely inhibited Ang II-mediated increase in FN mRNA levels. Inhibitors of protein kinase C (PKC), protein-tyrosine kinase (PTK), phosphatidylinositol-specific phospholipase C, Ras, phosphatidylinositol 3-kinase, p70 S6 kinase, and Ca2+/calmodulin kinase also decreased Ang II-induced activation of FN mRNA. In contrast, cycloheximide; PD123319; or inhibitors of Gi, protein kinase A, or mitogen-activated protein kinase kinase did not affect the induction. FN promoter contained a putative AP-1 binding site (rFN/AP-1; -463 to -437), and the results of a transient transfection and electrophoretic mobility shift assay showed that Ang II enhanced rFN/AP-1 activity. CV11974 and inhibitors of PKC or PTK suppressed Ang II-mediated increases in rFN/AP-1 activity, although neither PD123319 nor a protein kinase A inhibitor affected the induction. Furthermore, mutation of rFN/AP-1 that disrupted nuclear binding suppressed Ang II-induced transcription in the native FN promoter (-1908 to +136) context. Thus, Ang II activates transcription of the FN gene through the Ang II type 1 receptor in vascular smooth muscle cells, at least in part, via the activation of AP-1 by a signaling mechanism dependent on PKC and PTK.

Angiotensin II↗
PubMed1998

NMR structure of the Streptomyces metalloproteinase inhibitor, SMPI, isolated from Streptomyces nigrescens TK-23: another example of an ancestral beta gamma-crystallin precursor structure.

The Streptomyces metalloproteinase inhibitor, SMPI, isolated from Streptomyces nigrescens TK-23, is a proteinaceous metalloproteinase inhibitor, and consists of 102 amino acid residues with two disulfide bridges. SMPI specifically inhibits metalloproteinases such as thermolysin. In the present work, the solution structure of SMPI was determined on the basis of 1536 nuclear Overhauser enhancement derived distance restraints and 52 dihedral angle restraints obtained from three-bond spin coupling constants. The final ensemble of 20 NMR structures overlaid onto their mean coordinate with backbone (N, Calpha, C') r.m.s.d. values of 0. 45(+/-0.11) A and 0.57(+/-0.18) A for residues 6 to 99 and the entire 102 residues, respectively. SMPI is essentially composed of two beta-sheets, each consisting of four antiparallel beta-strands. The structure can be considered as two Greek key motifs with 2-fold internal symmetry, a Greek key beta-barrel. One unique structural feature found in SMPI is in its extension between the first and second strands of the second Greek key motif. Interestingly, this extended segment is known to be involved in the inhibitory activity of SMPI. In the absence of sequence similarity, the SMPI structure shows clear similarity to both domains of the eye lens crystallins, both domains of the calcium sensor protein-S, as well as the single-domain yeast killer toxin. The yeast killer toxin structure was thought to be a precursor of the two-domain beta gamma-crystallin proteins, because of its structural similarity to each domain of the beta gamma-crystallins. SMPI thus provides another example of a single-domain protein structure that corresponds to the ancestral fold from which the two-domain proteins in the beta gamma-crystallin superfamily are believed to have evolved.

Amino Acid Sequence↗
PubMed1998

Elucidation of the mode of interaction of thermolysin with a proteinaceous metalloproteinase inhibitor, SMPI, based on a model complex structure and a structural dynamics analysis.

SMPI is a proteinaceous microbial metalloproteinase inhibitor that was isolated from Streptomyces nigrescens TK-23 in 1979. SMPI is known to selectively inhibit the metalloproteinases in the gluzincin family, according to the Rawling and Barrett classification. There has been no report on the interaction of a metalloproteinase in the family of gluzincins with its specific proteinaceous inhibitor. We have solved the solution structure of SMPI by NMR. Here, we report the binding mode of SMPI to thermolysin, based on the model complex structure generated using our high-resolution NMR structure of SMPI and the crystal structure of thermolysin. The obtained complex model shows that the extruded loop of SMPI, with the scissile bond Cys64-Val65, is complementary in shape to the active cleft of thermolysin. In the complex, the Cys64 (P1) carbonyl oxygen atom can form a tetrahedral coordination to the active zinc in thermolysin, and simultaneously, the methyl groups of Val65 (P1') are closely located in the hydrophobic S1' pocket in thermolysin. From the electrostatic potential surface calculation, the active loop of SMPI and the active cleft in thermolysin have been shown to be complementary in the surface charge distribution, resulting in the stabilization of the complex. The apparently large active loop is less flexible, but maintains a conformation in the nano- to picosecond time-scale, as elucidated from the 15N spin relaxation analysis. This is a quite different structural feature of SMPI from the flexible binding loop generally found in the serine proteinase inhibitors, such as SSI and eglin c, and can be related to the narrow specificity of SMPI. The present study provides the first insight into the interaction between a proteinaceous inhibitor and a gluzincin metalloproteinase.

Bacterial Proteins↗
PubMed1998

Suppression of adenovirus E1A-induced apoptosis by mutated p53 is overcome by coexpression with Id proteins.

The rat 3Y1 derivative cell lines, EId10 and EId23, established by introducing the adenovirus E1A12S, Id-1H, and Id-2H cDNAs linked to the hormone-inducible promoter, express these proteins upon treatment with dexamethasone and elicit apoptosis, although these cell lines express mutated p53. The E1A mutants containing a deletion in either the N terminus or the conserved region 1 were unable to induce apoptosis in cooperation with Ids. Western blot analysis of the immunoprecipitates prepared from the dexamethasone-treated EId10 cell extract showed that Id-2H preferentially binds to E1A and E2A (E12/E47) helix-loop-helix transcription factors in vivo, but scarcely to the retinoblastoma protein. After induction of E1A and Ids, EId10 and EId23 cells began to accumulate in S phase and undergo apoptosis before entering G2 phase, suggesting that abnormal synthesis of DNA induced by coexpression of E1A, Id-1H, and Id-2H results in the induction of apoptosis. Apoptosis also is induced in mouse A40 (p53-/-) cells by E1A alone or E1A plus Ids after transient transfection of the expression vectors. The induction of apoptosis is stimulated by coexpression with wild-type p53; however, apoptosis induced by E1A alone was suppressed completely by coexpression with mutated p53, whereas apoptosis induced by E1A plus Ids was stimulated by the mutated p53 as done by wild-type p53. These results suggest that the suppressive function of mutated p53 is overcome by Ids.

Adenovirus E1A Proteins↗
PubMed1998

A novel E2F binding protein with Myc-type HLH motif stimulates E2F-dependent transcription by forming a heterodimer.

The human embryonal carcinoma cells NEC14 can be induced to differentiate morphologically by the addition of 10(-2) M N, N'-hexamethylene-bis-acetamide and cease to grow in several days. Transcription factors of the E2F/DP family have been shown to be closely related to the regulation of cell proliferation. To analyse cellular proteins which interact with E2F in NEC14 cells, cDNA clones encoding E2F binding proteins were isolated from a lambdaZAP II NEC14 cell library with the 32P-labeled GST (Glutathione S-transferase)-E2F-1 fusion protein as a probe. One of the clones encodes E2FBP1 which has the helix-loop-helix (HLH) motif, but lacks the basic domain and the zipper structure usually found at N- and C-terminal sides to the HLH motif, respectively. The arrangement of amino acids in the helix 1 and helix 2 regions is quite similar to those of Mxi and Mad, but different from those of E2F-1 and DP-1. Western blot analysis of the immunoprecipitates prepared with anti-E2FBP1 antibody showed that E2FBP1 associates with both E2F-1 and DP-1 in vivo. E2FBP1 alone has no DNA binding activity, but bind to the E2F site through heterodimerization with E2F-1 but not with DP-1. Although E2FBP1 lacks the transactivation domain, it stimulates E2F site-dependent transcription in cooperation with E2F-1.

Acetamides↗
PubMed1998

Stabilization of p53 by adenovirus E1A occurs through its amino-terminal region by modification of the ubiquitin-proteasome pathway.

The human epidermoid carcinoma-derived cell line MA1, established by introduction of the adenovirus E1A 12 S cDNA linked to the hormone-inducible promoter, elicits apoptosis after induction of E1A12 S in response to dexamethasone. E1A expression caused accumulation of wild type p53 more than 10-fold within 24 h after dexamethasone treatment. The cell lines that express E1A mutants containing a deletion either in the amino terminus or the conserved region 1 were unable to accumulate p53. p53 accumulated was degraded efficiently in vitro in the S10-0 extract (S10-0) prepared from MA1 cells in an ATP and ubiquitin-dependent manner, but not in S10-24 prepared after treatment with dexamethasone for 24 h. The p53 polyubiquitination activity in S100-0 was calcium-dependent and reduced greatly in S100-24. Ubiquitin affinity chromatography revealed that p53 ubiquitination activity in eluates thought to contain ubiquitin-conjugating enzymes decreased greatly in S100-24 as compared with S100-0. The accumulation of p53 was accompanied by the increase in the level of Mdm2, which has been shown to degrade p53 through binding to it. The high p53 level, however, was maintained until the late stage of the apoptotic process. These results indicate that the stabilization of p53 by E1A occurs through modification of a ubiquitin-specific enzyme(s) in the ubiquitin-proteasome pathway.

Adenovirus E1A Proteins↗
PubMed1998

Two sib cases of Leber congenital amaurosis with cerebellar vermis hypoplasia and multiple systemic anomalies.

Leber's congenital amaurosis (LCA), a type of congenital blindness, is clinically and genetically heterogeneous and often associated with systemic anomalies. We report on two sisters who were born to a consanguineous couple and had retinitis pigmentosa-like pigmented retinal lesions, alternating exotropia, bilateral cataracts, and anomalous coarse facies characterized by deformed skull with narrow forehead, low anterior hairline, hypertelorism, short philtrum, thin upper lip, and prominent jaw; cerebellar vermis hypoplasia; dilatation of the fourth ventricle; severe mental retardation; tremor; brisk deep tendon reflexes and abnormal behavior; and skeletal abnormalities such as limited extension of elbow and/ or finger joints and talipes equinovalgus. Skin defect and renal anomalies were seen in only one patient. Our patients are the first familial LCA associated with cerebellar vermis hypoplasia, and the disease involving particular multiple systemic anomalies may represent a distinct clinical entity.

Abnormalities, Multiple↗
PubMed1998

Do obesity and non-insulin dependent diabetes mellitus aggravate exercise-induced microproteinuria?

We evaluated the role of obesity in proteinuria by treadmill exercising of simple obese subjects and non-obese subjects with non-insulin dependent diabetes mellitus in whom the albumin excretion rate at rest was within normal range. Non-obese healthy volunteers were studied as the controls. The fractional renal clearances of four endogenous proteins, albumin, IgG, IgG4, and beta2-microglobulin were measured before, during, and after treadmill exercise in 17 simple obese and 15 non-obese diabetic subjects, and in 21 normal subjects. Exercise increased the fractional albumin clearance in all groups. In diabetic subjects, the fractional IgG4 clearance also increased: fractional beta2-microglobulin clearance increased in normal controls and in diabetics. In obese subjects, the fractional clearances of albumin, IgG, and IgG4 were similar to those in normal controls, but fractional beta2-microglobulin clearance was significantly lower. These results suggest that enhanced microalbuminuria in obese subjects is probably of glomerular origin. In normal subjects and diabetics, exercise-induced microproteinuria is probably of both glomerular and tubular origin. Defect in the charge-selective barrier of the glomerular capillary wall has been implicated in diabetics. Thus some additional factors relevant to obesity must be taken into account in the consideration of the mechanism of microalbuminuria in diabetics with obesity.

Adolescent↗
PubMed1998

Cloning and characterization of BAI-associated protein 1: a PDZ domain-containing protein that interacts with BAI1.

Brain-specific angiogenesis inhibitor 1 (BAI1), which is a p53-target gene specifically expressed in brain, encodes a seven-span transmembrane protein. Using a two-hybrid system, we isolated a cDNA that encodes a protein, named BAP1 (BAI1-associated protein), which interacts with the cytoplasmic region of BAI1. BAP1 is a novel member of the MAGUK (membrane-associated guanylate kinase homologue) family; it possesses a guanylate kinase domain, WW domains, and multiple PDZ domains. Interaction between BAI1 and BAP1 was mediated by a QTEV motif in the carboxy-terminal region of BAI1 and PDZ domains of BAP1. By immunocytochemical analysis of COS-7 cells transfected with BAI1 and BAP1, both products were co-localized at the cytoplasmic membrane, especially at cell-cell junctions. Cells transfected with BAI1 formed filopodia-like cytoplasmic extensions. These results suggest that BAI1 and BAP1 might be involved in cell adhesion and signal transduction in brain.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Intracellular retention and degradation of tissue-nonspecific alkaline phosphatase with a Gly317-->Asp substitution associated with lethal hypophosphatasia.

One point mutation which converts glycine-317 to aspartate of tissue-nonspecific alkaline phosphatase (TNSALP) was reported to be associated with lethal hypophosphatasia (Greenberg, C. R., et al. Genomics 17, 215-217, 1993). In order to define the molecular defect of TNSALP underlying the pathogenesis of hypophosphatasia, we have examined the biosynthesis of TNSALP with a Gly317-->Asp substitution. When expressed in COS-1 cells, the mutant did not exhibit alkaline phosphatase activity at all, indicating that the replacement of glycine-317 with aspartate abolishes the catalytic activity of TNSALP. Pulse-chase experiments showed that the newly synthesized mutant failed to acquire Endo H-resistance and to reach the cell surface. Interestingly, this TNSALP mutant was found to form a disulfide-bonded high-molecular-mass aggregate and was rapidly degraded within the cell, though the mutant protein was modified by glycosylphosphatidylinositol (GPI). Lactacystin, an inhibitor of the proteasome, obstructed the degradation of the mutant protein, suggesting the involvement of proteasome as a part of quality control of TNSALP.

Alkaline Phosphatase↗
PubMed1998

Morphological examination of bone synthesis via direct administration of basic fibroblast growth factor into rat bone marrow.

Woven bone induced by direct injection of basic fibroblast growth factor (bFGF) into rat bone marrow was examined. On the first day after injection, fibrous tissues formed in the treated region of the bone marrow. Tissue-nonspecific alkaline phosphatase (TNAPase)-immunopositive osteoblastic cells and osteopontin immunopositive-extracellular matrices were observed in the fibrous tissues, indicating bone induction. On the fifth day, the bFGF-induced bone was found broadly in the bone marrow. In the originally existing bone, osteopontin-immunoreactivity was observed at cement lines, but not in the fully calcified matrix, whereas the woven bone displayed immunoreactivity throughout the matrix. Numerous TRAPase-positive osteoclasts were present on the surfaces of the woven bone, but no obvious cement line was observed. Therefore, both bone formation and resorption appeared highly active, without normal cellular coupling equilibrated between bone formation and resorption performed by osteoblasts and osteoclasts. On the tenth day, the bFGF-induced bone was almost replaced by bone marrow. Thus, bone formation actively occurred in the first half of the experimental period, whereas bone resorption came to be predominant thereafter. This study demonstrated that bFGF stimulates bone formation, which, however, is subject to subsequent resorption, probably due in part to the absence of coordinated cellular coupling between osteoclasts and osteoblasts.

Acid Phosphatase↗
PubMed1998

Morphogenesis of vertebral deformities in involutional osteoporosis. Age-related, three-dimensional trabecular structure.

STUDY DESIGN: The relation between the semiquantitative data of alteration in three-dimensional trabecular structure and deformities of the vertebral body was analyzed to clarify the morphogenesis of vertebral deformities in involutional osteoporosis. OBJECTIVES: To evaluate semiquantitatively the age-related alterations of the three-dimensional structure of trabeculae of the vertebral body and to clarify their relation to vertebral deformities in involutional osteoporosis. SUMMARY OF BACKGROUND DATA: Recent studies have shown that bone fractures and deformities in osteoporosis do not depend only on a reduced amount of bone tissue. There is no previous study on the relation between bone deformity and the alterations of the three-dimensional structure of trabeculae. METHODS: The second lumbar vertebrae were removed at autopsy from 25 patients who had no disease predisposing them to secondary osteoporosis and no severe vertebral deformities. The sections of the vertebral body were immersed in sodium hypochlorite solution to corrode the bone marrow. Atrophy of trabeculae and increased spacing between trabeculae were evaluated semiquantitatively under stereoscopic microscopy. The authors examined the relation between the semiquantitative data found in the autopsy vertebrae and the patterns and frequencies of each deformity of the second lumbar vertebrae in 99 patients with involutional osteoporosis. RESULTS: The most frequent vertebral deformity was wedge-shaped vertebrae with compression of the anterosuperior portion, and the alterations of the trabecular structure of the anterosuperior portion were severe and closely related to aging. Severe trabecular alterations with no relation to aging did not necessarily cause vertebral deformity. CONCLUSIONS: Trabecular abnormality, which is significantly correlated with aging, may be the necessary and sufficient condition for vertebral deformities in involutional osteoporosis.

Aged↗
PubMed1998

Activation of the rat cyclin A promoter by ATF2 and Jun family members and its suppression by ATF4.

Cyclin A plays an essential role in the G1 to S phase transition in the cell cycle. The expression of cyclin A is restrained during G0 and G1, but steeply induced at the G1/S boundary. Analysis of the rat cyclin A promoter elements with the 5' sequential deletion derivatives of the promoter fused to the luciferase cDNA indicated that the ATF/CRE motif primarily determines the inducibility at G1/S. Gel shift analysis of the complex formed at the ATF/CRE site indicated that the complex was not formed with the G0/G1 cell extract, but maximally formed with the late-G1 cell extract. The complex was supershifted by anti-JunD antibody, and Western blot analysis of the immune complexes prepared with anti-JunD antibody revealed the presence of ATF2, suggesting heterodimerization of JunD with ATF2. The cyclin A promoter in a reporter plasmid was activated by nearly 10-fold in quiescent rat 3Y1 cells by cotransfection with the expression of plasmids encoding ATF2 and Jun family members. In contrast, cotransfection with the ATF4 expression plasmid suppressed the promoter activation mediated by ATF2 and Jun family members. The expression of Jun family members during G1 to S progression was induced biphasically in early and late G1 and the level of JunD increased markedly at the G1/S, while that of ATF family members was gradually increased along with the G1 to S progression. These results indicate that the cyclin A promoter activity is regulated, at least in part, by relative amounts of the ATF and Jun family members.

Activating Transcription Factor 2↗
PubMed1998

Expressions of p53 and PCNA do not correlate with the international index or early response to chemotherapy in non-Hodgkin's lymphoma.

The expression of p53 and PCNA on deparaffinized sections of tumor was assessed in relation to the International Index and response to chemotherapy. Thirty-five non-Hodgkin's lymphoma (NHL) patients were divided into three groups: aggressive NHL, mantle cell lymphoma (MCL), and low-grade NHL. None of the expressions correlated with the International Index or early response to chemotherapy in any group. In low-grade NHL, none of the patients expressed p53. Only one of three patients with overexpression of p53 showed conformational change and alteration of sequence in exon 7 by PCR-SSCP and DNA sequencing. The results showed that p53 and PCNA staining were not useful for predicting early response to chemotherapy, and that their expressions had no correlation with the International Index.

Adult↗
PubMed1998

Influence of ANOVA design and anatomical standardization on statistical mapping for PET activation.

We have created images of z value, error, and variation components for a PET activation study using various ANOVA designs and anatomical standardization methods. Data were acquired in four PET centers. In each center, CBF was measured on six normal male subjects under resting and covert verb generation, three times for each. The images were anatomically standardized with LINEAR transformation, SPM (Ver. 95), HBA (Karolinska/Tohoku), or MICHIGAN (Minoshima). ANOVA was performed pixel by pixel to compute t (and z) for the task main effect (Verb vs Rest) in four different designs: (i) two way (subject and task) (2W), (ii) two-way with interaction (2WI), (iii) subject considered a random factor (2WI-MX), and (iv) three-way (subject, task, and replication) (3W). A large area extending from the Broca to the left premotor cortex was activated. The localization of the highest peak depended both on the anatomical standardization and on the ANOVA design, the variation ranging 3-4 cm. Smoothing reduced the variation while erasing possible subfoci. The z images of 2W, 2WI, and 3W looked alike, whereas 2WI-MX presented lower peak z values. SPM tended to present higher z values than the other methods. The error was high in the gray and low in the white matter. The root mean square for the subject effect was high on the border of gray matter especially in LINEAR and HBA, revealing intersubject mismatch in the gray matter distribution. The root mean square for the subject-by-task interaction effect revealed individual variation in activation.

Adult↗
PubMed1998

Data base and management system for clinical positron emission tomography (PET) studies.

A data base and management system connected to an image analysis system has been developed and utilized for clinical positron emission tomography (PET). This data base system, 1) is based on "GBASE", a general purpose data base, which runs on a UNIX work station, 2) works on a network file system and is connected to PET cameras and other data acquisition devices as well as to an image analysis system "Dr.View", 3) centrally manages the data stored in a data storage unit, 4) is easily modifiable and expandable, and 5) has a human friendly interface which requires minimum operation for registration, retrieval and management. We have been using this system to handle clinical PET data for seven years and have optimized the data base schema. As a result, this system has become a truly practical tool for the daily operation and is well-received by technologists, nuclear physicians and attending physicians.

Brain↗