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T Kumazaki

Publications and source records attributed to T Kumazaki.

At least 181 records · Page 10Linked to original sources
PubMed1992

Evidence for the involvement of tryptophan 38 in the active site of glutathione S-transferase P.

Glutathione S-transferase P (GST-P) exists as a homodimeric form and has two tryptophan residues, Trp28 and Trp38, in each subunit. In order to elucidate the role of the two tryptophan residues in catalytic function, we examined intrinsic fluorescence of tryptophan residues and effect of chemical modification by N-bromosuccinimide (NBS). The quenching of intrinsic fluorescence was observed by the addition of S-hexylglutathione, a substrate analogue, and the enzymatic activity was totally lost when single tryptophan residue was oxidized by NBS. To identify which tryptophan residue is involved in the catalytic function, each tryptophan was changed to histidine by site-directed mutagenesis. Trp28His GST-P mutant enzyme showed a comparable enzymatic activity with that of the wild type one. Trp38His mutant neither was bound to S-hexylglutathione-linked Sepharose nor exhibited any GST activity. These findings indicate that Trp38 is important for the catalytic function and substrate binding of GST-P.

Amino Acid Sequence↗
PubMed1992

Amino acid sequence and disulfide-bridge location of canine haptoglobin.

The complete amino acid sequence and disulfide-bridge location of canine haptoglobin (Hp) were determined by analyzing various fragments produced chemically and/or enzymatically. Canine Hp consists of two light (L) and two heavy (H) chains with 83 and 245 amino acid residues, respectively. It has three potential oligosaccharide-binding sequences, Asn-X-Ser/Thr, one in the L chain and two in the H chain. All of them are glycosylated. Comparison of the amino acid sequences between canine Hp and human Hp shows 68 and 85% homology for L chains and H chains, respectively. About 20% of the canine L chain still retains a carboxyl-terminal arginine residue, which is completely removed during maturation in human L-chain. The half-cystine residue at position 15 in the L chain, which participates in the inter-L chain disulfide bridging in human Hp, has been replaced by a leucine residue in canine Hp. Therefore, an LH unit in canine Hp may be joined to another LH unit by a noncovalent (mainly hydrophobic) interaction to form the complete molecule. The disulfide bridges in canine Hp link Cys-34L to Cys-68L, Cys-72L to Cys-105H, Cys-148H to Cys-179H, and Cys-190H to Cys-220H, as in the case of human Hp.

Amino Acid Sequence↗
PubMed1992

Cellular aging and expression of fibronectin.

Several changes in the functional characteristics of fibronectin (FN) have been noted as cells become senescent in culture. In a previous report we showed that the steady state level of FN mRNA increases significantly during the process of in vitro cellular aging in a fibroblast strain. Because a phenomenon observed in one cell strain may not be the case in other cell strains, we extended the previous study and confirmed that this is a common phenomenon in at least two fibroblast strains of different origin. The greatest change in the proportion of cells expressing high levels of FN occurs near the end of a culture's proliferative potential. The proportion of cells unable to synthesize DNA follows a similar pattern. We also found that increasing cell size correlates closely with higher levels of FN expression. Thus, there is a clear correlation between increased FN mRNA content and in vitro cellular senescence. In order to see if this phenomenon could also be observed in cells aged in vivo, we analyzed cells aged in vivo. We found that fibroblasts from donors of higher age show lower labeling index, express a higher level of FN and come to have a larger cell area, similar to cells aged in vitro. This strongly suggests that a fibroblast in vivo ages with aging of the individual in like manner to that observed in in vitro aging cells, that is, by exhausting division potential. This supports studies using in vitro aging cells as a model for cellular aging in vivo.

Cell Line↗
PubMed1992

Aberrant left gastric vein directly draining into left portal venous system. A case report.

A 66-year-old man with early gastric cancer and liver cirrhosis was diagnosed by preoperative angiography as having an aberrant left gastric vein communicating directly with the left lateral portal vein system. This communication was confirmed during operation for the gastric cancer. Our report is the first of an aberrant left gastric vein showing direct communication with the left portal vein system.

Aged↗
PubMed1992

[Management of type A acute aortic dissection--results of the cases with thrombosed false lumen].

By reviewing the outcome, we studied the propriety of our principles for the treatment of type A acute aortic dissection in 45 patients, encountered during the 10-year period between 1981 and 1990. We conducted a comparative study of patients with a thrombosed false lumen (type T) and a patent false lumen (type P) to examine the effect of an acutely thrombosed false lumen on the prognosis of this disease. For the 25 patients treated in the first 6 years (1981-1986), operation was performed as soon as exact diagnosis was made, regardless of the presence of complications and the type or severity of the disease. Early death occurred in 9/20 operated cases and in 4/5 unoperated cases, so 13/25 patients died for a 52.0% mortality rate. For the 20 patients who received treatment in the latter period (1987-1990), we gave priority to conservative treatment for type T cases that were free from complications, and adopted a treatment method attaching greater importance to the resection of intimal tears. As a results, early deaths were observed in only 4 type P patients (20.0%) who underwent operation, a significant better result (p < 0.05). For patients in whom we were able to excise the intimal tear (30.0%, early mortality rate), the results were better than in those in whom the intimal tear were left alone (53.8%). The results were particularly good in type T patients (25.0% of them underwent intimal tear resection and 71.4% underwent no operation for the intimal tear).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1992

Endothelin. Immunohistologic localization in aorta and biosynthesis by cultured human aortic endothelial cells.

BACKGROUND: Endothelin-1 (ET-1) has been shown to exist in many organs and to have various biologic functions including vasoconstriction. However, an exact location of ET gene expression of the tissues is not fully investigated. Human aortic tissue was examined to elucidate the exact location of ET gene expression. EXPERIMENTAL DESIGN: Human aortas were obtained at autopsy and fixed in either conventional 10% formalin or 3% paraformaldehyde. The aortic thin sections were subjected to examinations of an immunohistochemistry and in situ hybridization of ET-1. Human aortic endothelial cells were cultured by a previously reported method. ET-1 released in the supernatant from the cultured endothelial cells was radioimmunoassayed. RESULTS: Immunohistologic study of ET-1 revealed a linear staining of the endothelial monolayer and diffuse staining in the intimal and medial smooth muscle cells on human aorta except for fetal aorta. In situ hybridization signals were intense in the endothelial cells from the elderly as well as younger subjects as examined with 35S-labeled anti-sense probe RNA. Fetal aortic endothelial cells revealed the least signals that meant developing but still immature gene translation. Smooth muscle cells showed positive but weak in situ hybridization signals. Control immunohistologic and hybridization studies were negative. ET-1 biosynthesis by cultured human aortic endothelial cells was invariably low in the subjects under the age of 50, ranging from 0.23 to 0.40 pmol/1 x 10(5) cells for 3 days. On the other hand, endothelial cells from the elderly subjects generally synthesized a greater amount of endothelin in vitro. CONCLUSIONS: These findings indicate that ET-1 is most highly expressed in endothelial cells, although not as highly but certainly, expressed in intimal and medial smooth muscle cells. This fact gives a new insight into the biophysiologic and pathologic roles of ET. In addition, these methods are applicable to investigate the gene expression of ET-1 in all organs and tissues.

Adolescent↗
PubMed1991

[Development of a new digital angiography system--improvement of rotational angiography and three dimensional image display].

The prototype of a rotational digital angiography system, has been improved to expand its range of application. The new system features an improved hardware configuration and new digital processing device. The system, called "computerized dynamic stereoradiography", is based on rapid transverse rotation of the X-ray apparatus, serial circumferential radiography and binocular stereographic imaging. The new digital processing device was included in the apparatus to provide rotational digital angiography. In use, mask exposures are first taken and all data are collected on a real-time basis into frame memories. Immediately afterwards, the X-ray apparatus is returned to the starting point and and live images are obtained. Subtraction images of all frames can be produced by a keyboard operation that requires less than 10 seconds. Three-dimensional images are rendered by two display systems with a 5 degree angle of difference. These images move at the same speed of rotation of two cathode ray tubes with 1,024 lines per screen, so that optical 3-D images can be observed. Digital angiography without subtraction is also available in the new system in both rotational and sequential modes. This is particularly useful when examining emergency patients and those who cannot hold their breath during X-ray exposure. This paper presents the principle and theory of the new system, and discusses its potential for overcoming the problems presented by current angiographic procedures in clinical practice.

Angiography, Digital Subtraction↗
PubMed1991

[Value of "additional arterial embolization" to bilateral internal iliac TAE in patients with severe pelvic fractures].

Transcatheter arterial embolization (TAE) of the bilateral internal iliac arteries has been shown to be of great value in controlling retroperitoneal massive hemorrhage associated with pelvic fractures. It has recently been reported, however, that TAE of only the bilateral internal iliac arteries sometimes fails to stabilize the patient's hemodynamics. The purpose of the present study was to evaluate "additional arterial embolization" to the bilateral internal iliac TAE in hemodynamically unstable cases. Sixty-eight patients who underwent emergency TAE following severe pelvic fractures were reviewed. Additional arterial embolization of the lumbar arteries in four patients, middle sacral arteries in two and inferior epigastric artery in one was carried out following bilateral internal iliac TAE. The damage to these arteries was associated with fractures of the lumbar costal process, sacrum, pubis, etc. The patients were in stable condition after the procedure, and no significant complication was experienced. When fractures and dislocations of the above-mentioned bones are seen on plain X-ray films and arterial bleeding is identified by angiography, additional embolization of the arteries should be performed immediately.

Adult↗
PubMed1991

Fibronectin expression increases during in vitro cellular senescence: correlation with increased cell area.

Several changes in the functional characteristics of fibronectin have been noted as cells become senescent in culture. In this report we show that steady state levels of both fibronectin mRNA and protein increase significantly during the process of cellular aging. The greatest change in the proportion of cells expressing high levels of fibronectin occurs near the end of a culture's proliferative potential. The proportion of cells unable to synthesize DNA has previously been shown to follow a similar pattern. We also found that increasing cell size correlates closely with higher levels of fibronectin expression. Thus, there is a clear correlation between increased fibronectin mRNA content and in vitro cellular senescence. It remains to be determined whether the change in fibronectin production is a contributing cause or a result of in vitro cellular senescence.

Blotting, Northern↗
PubMed1991

Purification and characterization of Streptomyces griseus metalloendopeptidases I and II.

Two metalloendopeptidases, designated as Streptomyces griseus metalloendopeptidases I and II (SGMPI and SGMPII), were isolated from a commercial Pronase P by a method including affinity chromatography on carbobenzoxy-L-alaninyl-triethylenetetraminyl-Sepharose (Z-Ala-T-Sepharose). The two enzymes differed from each other in behavior on ion-exchange chromatography but showed the same amino-terminal sequence at least up to the 20th residue. Their molecular weights were both estimated to be 37,000 by SDS-polyacrylamide gel electrophoresis. Elemental and amino acid composition analyses indicated that both of them contained about 1 g atom of zinc and one cystine residue per mol of protein. Cleavage specificities of the two enzymes toward synthetic peptide-substrates were very similar to those observed with thermolysin. EDTA, o-phenanthroline, and phosphoramidon strongly inhibited these enzymes, while typical serine-protease inhibitors and cysteine-protease inhibitors had no effect. The findings clearly indicate that SGMPI and SGMPII can be classified into the family of zinc-endopeptidases. It was unexpectedly found, however, that these metalloendopeptidases were strongly inhibited by protein serine-protease inhibitors produced by Streptomycetes, such as Streptomyces subtilisin inhibitor (SSI), alkaline protease inhibitor-2c' (API-2c'), and plasminostreptin (PS).

Amino Acids↗
PubMed1991

Application of bimane-peptide substrates to spectrofluorometric assays of metalloendopeptidases.

A spectrofluorometric method for sensitive determination of metalloendopeptidase activity has been developed by using a bimane-peptide containing a tryptophan residue, i.e. 1,7-dioxo-2,5,6-trimethyl-1H,7H-pyrazolo[1,2-alpha]pyrazol-3-yl-methyl- thiomethylcarbonyl-phenylalanyl-tryptophanyl-leucine (Bim-SCH2CO-Phe-Trp-Leu-OH). Such an "intramolecularly quenched" substrate was originally designed for a sensitive assay of angiotensin I converting enzyme (ACE) [Sato, E. et al. (1989) Chem. Pharm. Bull. 37, 145-147]. All the typical metalloendopeptidases tested, such as thermolysin, Pseudomonas aeruginosa (Ps.) elastase, Streptomyces griseus metalloendopeptidases I and II (SGMPI and SGMPII), and alkinonase A, a metalloendopeptidase from Streptomyces violaceorectus, cleaved this substrate strictly at a Phe-Trp bond, leading to a marked increase in fluorescence. Kinetic parameters of the enzymatic hydrolyses of five kinds of analogous bimane substrates were compared to examine how the nature of neighboring amino acid residues on either side of the cleavable bond affects the catalytic efficiency of each of the metalloendopeptidases. Bim-SCH2CO-Phe-Trp-Leu-OH was most efficiently hydrolyzed by all of these enzymes. The use of this substrate made it possible to determine minute amounts of metalloendopeptidases, especially those originating from Streptomycetes (for example, as little as 10 fmol of SGMPII).

Amino Acid Sequence↗
PubMed1991

Interactions of Streptomyces serine-protease inhibitors with Streptomyces griseus metalloendopeptidase II.

Streptomyces griseus metalloendopeptidase II (SGMPII) was shown to form tight complexes with several Streptomyces protein inhibitors which had been believed to be specific to serine proteases, such as Streptomyces subtilisin inhibitor (SSI), plasminostreptin (PS), and alkaline protease inhibitor-2c' (API-2c'), as well as with Streptomyces metalloprotease inhibitor (SMPI). The dissociation constants of complexes between SGMPII and these inhibitors were successfully determined by using a novel fluorogenic bimane-peptide substrate. The values ranged from nM to pM. The results of studies by gel chromatographic and enzymatic analyses indicated that SGMPII is liberated from the complex with SSI by the addition of subtilisin BPN'. SGMPII and subtilisin BPN' proved, therefore, to interact with SSI in a competitive manner, despite the difference in the chemical nature of their active sites.

Base Sequence↗
PubMed1991

Effect of an iso-osmolar contrast medium on pulmonary arterial pressure at pulmonary angiography.

A clinical comparison of the effects on pulmonary arterial pressure induced by contrast media with various osmolalities, iohexol 140 mg I/ml (300 mosm/kg H2O), iohexol 300 mg I/ml (690 mosm/kg H2O), and diatrizoate 292 mg I/ml (1480 mosm/kg H2O) following selective pulmonary angiography was made in 12 patients with normal pulmonary arterial pressure. A double-blind crossover study was performed and the contrast media were administered in random order. The pulmonary arterial pressure was recorded continuously before, during, and for 3 min after the injection. The effect of iohexol 140 on the pulmonary arterial pressure was significantly less marked than that of diatrizoate 292, whereas no statistical significance was shown between iohexol 140 and iohexol 300. These results indicate that iso-osmolar contrast medium (iohexol 140), as well as iohexol 300, would be better tolerated than diatrizoate 292, and is therefore a safer contrast medium for selective pulmonary angiography.

Adult↗
PubMed1990

[Clinical assessment of rotational digital angiography for the diagnosis of aortic dissection].

Rotational digital angiography was performed in five patients with aortic dissection. Intimal tears, intimal flap and involvement of major branches were clearly demonstrated in two patients with opacified false lumen. Ulcer-like projections were also identified in three patients with thrombosed false lumen. The device has, therefore, been found to be of great value in diagnosing aortic dissection particularly for the detection of intimal tear sites and ulcer-like projections.

Aortic Dissection↗
PubMed1990

[Change of renal function immediately after angiography].

Abdominal angiography using ioxaglate (3.0-4.5 ml/kg) was performed in 10 patients with normal renal function. Ccr, FENa, CH2O were compared before and immediately after angiography. There was no significant change in Ccr and CH2O level, while FENa increased remarkably after angiography. This study suggested that the osmotic diuresis and the proximal tubular stress were induced by administrated low osmolality contrast material during conventional abdominal angiography.

Aged↗
PubMed1990

Intraoperative real-time ultrasonic scanning for microwave coagulation of the prostate.

Nine patients with severe dysuria caused by prostatic cancer received prostatic microwave coagulation under intraoperative real-time ultrasonic scanning. During the procedure, the microwave applicator was clearly observed, and the coagulation region appeared as an hyperechoic area compared to the noncoagulated region. Intraoperative real-time ultrasonic scanning allowed safer and more efficacious application of prostatic microwave coagulation.

Adult↗