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Biomedical subjects

T Takagi

Publications and source records attributed to T Takagi.

At least 451 records · Page 25Linked to original sources
PubMed1994

Binding characteristics of antitype II collagen antibody to the surface of diseased human cartilage as a probe for tissue damage.

OBJECTIVE: Studies have shown that collagen type II (CII) on the intact articular surface of cartilage is partially protected from binding to anti-CII antibodies by material proteinaceous in nature, not present in synovial fluid, synthesized by resident chondrocytes, and exquisitely sensitive to polymorphonuclear (PMN) attack and neutrophil elastase digestion. Thus, anti-CII antibody differential binding to articular cartilage surfaces before and after brief neutrophil elastase digestion may be used as a sensitive marker of cartilage damage. METHODS: We measured binding of anti-CII antibodies to the pannus-free articular surfaces of 4 normal, 11 rheumatoid (RA), and 10 osteoarthritic (OA) cartilage specimens, before and after brief digestion with PMN elastase. In addition, antibody binding was quantitated with an antiserum against a 4 M guanidine extract of human cartilage surface. RESULTS: Whereas anti-CII binding increased 59.0% +/- 2.8 after 1 h incubation of normal cartilage with elastase, both the RA and OA specimens failed to show significant increases (RA: 1.0 +/- 0.1; p < 0.001; OA: 27.2% +/- 1.6, p < 0.05). Moreover, anti-CII antibody binding to untreated cartilage specimens was highest for the RA group (Normal: 189.2.1 +/- 38.7 pg anti-lg/mg tissue; RA: 407.5 +/- 80.6, p < 0.05; OA: 243.6 +/- 50.6, NS). Concomitant binding studies with antiserum against cartilage surface material showed greater antibody binding to the articular surfaces than to the cut cartilage surfaces in normal and OA specimens. RA cartilage samples exhibited somewhat smaller antibody binding to the articular surfaces. CONCLUSION: Our studies suggest that in human inflammatory and noninflammatory arthritides the articular cartilage surface undergoes alterations that can be detected by differential binding with anti-CII antibodies, before and after brief digestion with PMN elastase.

Adolescent↗
PubMed1993

Noninvasive assessment of left internal mammary artery graft patency using duplex Doppler echocardiography from supraclavicular fossa.

OBJECTIVES: The purpose of this study was to clarify the usefulness of duplex Doppler echocardiography from the supraclavicular fossa for assessment of left internal mammary artery graft patency. BACKGROUND: A noninvasive method to assess coronary artery bypass graft patency would be useful for clinical diagnosis and long-term follow-up of graft outcome. METHODS: Duplex Doppler echocardiography from the supraclavicular fossa was performed in 56 consecutive patients who underwent postoperative cardiac catheterization studies, including quantitative angiography. All patients underwent coronary artery bypass graft surgery using the left internal mammary artery graft to the left anterior descending coronary artery. RESULTS: The left internal mammary artery graft and its flow were detected in 55 (98%) of the 56 patients with duplex Doppler echocardiography from the supraclavicular fossa. According to the quantitative angiographic data, the patients were assigned to three groups: group A (36 patients) with a normal left internal mammary artery graft (< 50% diameter stenosis), group B (9 patients) with intermediate (50% to 75% diameter) graft stenosis and group C (10 patients) with severe (> 75% diameter) graft stenosis. The diastolic/systolic peak velocity ratio was smaller in group C than in groups A and B (p < 0.05), but there was no significant difference between groups A and B. A diastolic/systolic peak velocity ratio < 0.6 predicted severe left internal mammary artery graft stenosis (> 75% diameter stenosis) with a sensitivity and specificity of 100% and 80%, respectively. The diastolic fraction of time-velocity integral was smaller in group C than in groups A and B (p < 0.05), but there was no significant difference between groups A and B. A diastolic fraction < 0.5 predicted significant left internal mammary artery graft stenosis (> 75% diameter stenosis) with a sensitivity and specificity of 90% and 100%, respectively. CONCLUSIONS: Duplex Doppler echocardiography from the supraclavicular fossa is useful for noninvasive assessment of left internal mammary artery graft patency.

Adult↗
PubMed1993

Characterization of further association of the trimeric membrane protein porin by low-angle laser-light scattering photometry coupled with high-performance gel chromatography.

Porin (OmpF), a trimeric membrane protein, in an extract of the outer membrane of Escherichia coli gave a twin-peaked elution pattern on Sephacryl S-300HR gel chromatography in the presence of sodium dodecyl sulphate. The species eluting earlier and later were found to be the hexamer and trimer, respectively, from molecular mass determination by low-angle laser-light scattering photometry coupled with TSK-G3000SWXL gel chromatography. As the hexamer was dissociated into the trimer under the conditions of sodium dodecyl sulphate polyacrylamide gel electrophoresis, its presence had been overlooked. The addition of lipopolysaccharide, another component of the outer membrane, and subsequent dialysis induced association of the trimer, the product containing an appreciable amount of the hexamer.

Chromatography, Gas↗
PubMed1993

Differential responses of intestinal glucose transporter mRNA transcripts to levels of dietary sugars.

Dietary sugars are known to stimulate intestinal glucose transport activity, but the specific signals involved are unknown. The Na(+)-dependent glucose co-transporter (SGLT1), the liver-type facilitative glucose transporter (GLUT2) and the intestinal-type facilitative glucose transporter (GLUT5) are all expressed in rat jejunum [Miyamoto, Hase, Taketani, Minami, Oka, Nakabou and Hagihira (1991) Biochem. Biophys. Res. Commun. 181, 1110-1117]. In the present study we have investigated the effects of dietary sugars on these glucose transporter genes. A high-glucose diet stimulated glucose transport activity and increased the levels of SGLT1 and GLUT2 mRNAs in rat jejunum. 3-O-Methylglucose, D-galactose, D-fructose, D-mannose and D-xylose can mimic the regulatory effect of glucose on the SGLT1 mRNA level in rat jejunum. However, only D-galactose and D-fructose increased the levels of GLUT2 mRNA. The GLUT5 mRNA level was increased significantly only by D-fructose. Our results suggest that the increase in intestinal transport activity in rats caused by dietary glucose is due to an increase in the levels of SGLT1 and GLUT2 mRNAs, and that these increases in mRNA may be caused by an enhancement of the transcriptional rate. Furthermore, for expression of the SGLT1 gene, the signal need not be a metabolizable or transportable substrate whereas, for expression of the GLUT2 gene, metabolism of the substrate in the liver may be necessary for signalling. Only D-fructose is an effective signal for expression of the GLUT5 gene.

Animals↗
PubMed1993

Identification of the product of the murine ST2 gene.

The murine ST2 gene is expressed in growth-stimulated BALB/c-3T3 cells. This gene encodes a protein that is similar to the extracellular portions of the interleukin-1 receptors (types 1 and 2). In this study, we prepared a polyclonal antibody against the recombinant ST2 protein produced in Escherichia coli. This antibody detected recombinant ST2 protein in the culture fluid of COS7 cells transfected with a mammalian expression vector (pEF-BOS) carrying ST2 cDNA. Using this antibody, we could detect the ST2 protein in the culture fluid of growth-stimulated BALB/c-3T3 cells, and in the medium of continuously growing cells, but not in that of growth-arrested cells. ST2 proteins produced in COS7 cells and BALB/c-3T3 cells were N-glycosylated as predicted from nine putative N-glycosylation sites in its deduced amino-acid sequence.

3T3 Cells↗
PubMed1993

Monoclonal antibodies to human polymorphonuclear leukocyte gelatinase (type IV collagenase) are cross-reactive with fibroblast gelatinase.

Four monoclonal antibodies to human polymorphonuclear leukocyte gelatinase, 100 kDa type IV collagenase, 1G5, 4C6, 4G6 and 4H4 clones, were generated by immunizing Balb/c mice and fusing the mouse spleen cells with P3U1 cells. By using the enzyme-linked immunosorbent assay method, two clones, 4G6 and 1G5, were found to cross-react with human fibroblast 75kDa gelatinase, although none of the four antibodies inhibited gelatinase activity. Selective detection of 75 kDa and 100 kDa gelatinases produced by human skin fibroblasts and fibrosarcoma cells (HT 1080) in culture was successfully demonstrated by immunostaining with combined uses of 4H4 and 4G6 clones.

Antibodies, Monoclonal↗
PubMed1993

Polymorphic hemoglobin from a midge larva (Tokunagayusurika akamusi) can be divided into two different types.

The hemoglobin from the 4th-instar larva of Tokunagayusurika akamusi, a common midge found in eutrophic lakes in Japan, was composed of as many as 11 separable components (IA, IB, II, III, IV, V, VIA, VIB, VII, VIII, IX) on a DEAE-cellulose column. However, we have found that these components can be divided into two groups on the basis of their spectroscopic properties, one being named as the normal type (N-type) and the other being referred to as the low type (L-type). Since the major difference between them seemed to be the presence or absence of the distal (E7) histidine residue, which plays an important role in the stability properties of the bound dioxygen, the complete amino acid sequence was then determined for each typical component, namely, VII (N-type) and V (L-type): the former hemoglobin contained the usual distal histidine residue at position 64, whereas the latter one replaced it by isoleucine at position 66. The homology test for 40 N-terminal amino acid residues of all components also demonstrates that T. akamusi hemoglobin is composed of two different clusters showing a very early separation in the phylogenetic tree.

Amino Acid Sequence↗
PubMed1993

Primary structure of Tetrahymena hemoglobins.

The primary structure of hemoglobins of Tetrahymena thermophila and T. pyriformis was determined by peptide and cDNA sequence analysis. Their sequences were 83.5% identical to each other and homologous to other protozoan and cyanobacteria hemoglobins, but not to proteins of the globin family. An intron was not present in the T. thermophila hemoglobin gene.

Amino Acid Sequence↗
PubMed1993

Cation binding and conformation of tryptic fragments of Nereis sarcoplasmic calcium-binding protein: calcium-induced homo- and heterodimerization.

Nereis sarcoplasmic calcium-binding protein (NSCP) is a compact 20-kDa protein that competitively binds three Ca2+ or Mg2+ ions and displays strong positive cooperativity. Its three-dimensional structure is known. It thus constitutes a good model for the study of intramolecular information transduction. Here we probed its domain structure and interaction between domains using fragments obtained by controlled proteolysis. The metal-free form, but not the Ca2+ or Mg2+ form, is sensitive to trypsin proteolysis and is preferentially cleaved at two peptide bonds in the middle of the protein. The N-terminal fragment 1-80 (T1-80) and the C-terminal fragment 90-174 (T90-174) were purified to electrophoretic homogeneity. T1-80, which consists of a paired EF-hand domain, binds one Ca2+ with Ka = 3.1 x 10(5) M-1; entropy increase is the main driving force of complex formation. Circular dichroism indicates that T1-80 is rich in secondary structure, irrespective of the Ca2+ saturation. Ca2+ binding provokes a difference spectrum which is similar to that observed in the intact protein. These data suggest that this N-terminal domain constitutes the stable structural nucleus in NSCP to which the first Ca2+ binds. T90-174 binds two Ca2+ ions with Ka = 3.2 x 10(4) M-1; the enthalpy change contributes predominantly to the binding process. Metal-free T90-174 is mostly in random coil but converts to an alpha-helical-rich conformation upon Ca2+ binding. Ca2+ binding to T1-80 provokes a red-shift and intensity decrease of the Trp fluorescence but a blue-shift and intensity increase in T90-174.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗