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Biomedical subjects

T Takatsu

Publications and source records attributed to T Takatsu.

At least 19 recordsLinked to original sources
PubMed1995

Vertebral slip in lumbar spondylolysis and spondylolisthesis. Long-term follow-up of 22 adult patients.

We studied the aetiology of vertebral slip in a long-term follow-up of 22 adult patients with isthmic spondylolysis or spondylolisthesis of L5. Of the 18 with spondylolysis without slip, 13 showed no slip after ten years, but five developed displacement of over 5%. All four patients with spondylolisthesis showed progression of the slip. We found that the vertical thickness of the transverse process of L5 was significantly greater (p < 0.01) in the 13 patients with no slip than in the other two groups. The relationship of vertebral slip to the shape of the transverse processes of L5 may be explained by differences in the bulk or physiological strength of the posterior bands of the iliolumbar ligament.

Adolescent↗
PubMed1995

Effect of pulpal pressure on adhesion of resin composite to dentin: bovine serum versus saline.

The purpose of this study was to compare the tensile bond strengths of resin composite to dentin, mediated by two new bonding systems (Scotchbond Multi-Purpose and Clearfil Liner Bond II), under simulated pulpal pressure when diluted bovine serum or saline was used as the pulpal fluid. The bond strengths of the two bonding systems to dentin (under a pulpal pressure of 15 cm of water) obtained when bovine serum was used were statistically significantly higher than those obtained when saline was used. These data suggest that the primers of these bonding systems decreased the dentinal permeability when the bovine serum pulpal fluid was used through the precipitation of serum proteins by the primers in the dentinal tubules. This may have allowed better penetration of the bonding resin monomers into the conditioned dentinal structure, thus improving the bond strength. These findings support the idea that topical application of dentinal bonding systems may be an effective therapy for treating hypersensitive dentin.

Animals↗
PubMed1994

Relationship between surface area for adhesion and tensile bond strength--evaluation of a micro-tensile bond test.

OBJECTIVES: The purpose of this study was to test the null hypothesis that there is no relationship between the bonded surface area of dentin and the tensile strength of adhesive materials. METHODS: The enamel was removed from the occlusal surface of extracted human third molars, and the entire flat surface was covered with resin composite bonded to the dentin to form a flat resin composite crown. Twenty-four hours later, the bonded specimens were sectioned parallel to the long axis of the tooth into 10-20 thin sections whose upper part was composed of resin composite with the lower half being dentin. These small sections were trimmed using a high speed diamond bur into an hourglass shape with the narrowest portion at the bonded interface. Surface area was varied by altering the specimen thickness and width. Tensile bond strength was measured using custom-made grips in a universal testing machine. RESULTS: Tensile bond strength was inversely related to bonded surface area. At surface areas below 0.4 mm2, the tensile bond strengths were about 55 MPa for Clearfil Liner Bond 2 (Kuraray Co., Ltd.), 38 MPa for Scotchbond MP (3M Dental Products), and 20 MPa for Vitremer (3M Dental Products). At these small surface areas all of the bond failures were adhesive in nature. SIGNIFICANCE: This new method permits measurement of high bond strengths without cohesive failure of dentin. It also permits multiple measurements to be made within a single tooth.

Composite Resins↗
PubMed1994

The influence of age and depth of dentin on bonding.

OBJECTIVES: The purpose of this study was to investigate what influence the two variables of dentin depth and age may have on the tensile bond strengths of three bonding systems. METHODS: Dentin discs prepared from human molars were divided into young and old, superficial and deep surfaces. Three bonding systems, Scotchbond Multi-purpose (3M Dental Products), Superbond D-liner (Sun Medical Co.), and Liner Bond II (Kuraray Co.) were the materials tested for tensile bond strength. In addition, the structural variation of the resin-impregnated, or hybrid, layer was compared among the two variables and three bonding systems. RESULTS: Tensile bond strengths exceeding 10 MPa were obtained for all materials. After ANOVA, an effect on tensile bond strength could be attributed to dentin age or depth for only Superbond D-liner used on deep-young dentin as compared with old-superficial dentin. All other group comparisons failed to show any variation between dentin depth or age. However, specimens bonded to deeper dentin showed slightly lower strengths. SEM observations showed thicker resin-impregnated layers for Scotchbond MP and Superbond D-liner compared with Liner Bond II. Liner Bond II exhibited a thinner and more diffuse resin-impregnated layer, believed to be due to the different dentin conditioning method. SIGNIFICANCE: Dentin age or depth may not show as great an influence on bond strengths with the newer type of bonding systems. The resin-impregnated layer quality, rather than thickness, is believed to be the most important factor for obtaining high tensile bond strengths.

Age Factors↗
PubMed1992

Redundant nerve roots of the cauda equina caused by lumbar spinal canal stenosis.

To investigate pathogenesis of redundant nerve roots of the cauda equina, which were concomitant with severe lumbar spinal canal stenosis, six cadavers were examined anatomically and histopathologically, and quantitative analysis of nerve fibers was performed. In this anatomic study, it was observed that all the redundant nerve roots passed through the constriction of the spinal canal. No significant pathologic change was detected in the spinal ganglia and in the spinal cords except for the posterior column, in which dorsal redundant roots were entering. Redundant nerve roots of unequal length also were observed in the anatomic study. The spatial distribution of redundant nerve roots and the extent of degeneration of nerve fibers in them were established by these histopathologic and quantitative studies. These facts indicated a close causal relationship between redundant nerve roots and constriction of the spinal canal, and that the pathogenesis of redundant nerve roots was a squeezing force acting on the nerve roots at the area of spinal canal constriction.

Cauda Equina↗
PubMed1990

Aladapcin, a new microbial metabolite that enhances host resistance against bacterial infection. Production, isolation, physico-chemical properties and biological activities.

We have constructed a new screening system for detecting microbial products that enhance host resistance against bacterial infection. It was found that a new compound with such activity is produced by a soil isolate classified as Nocardia sp. SANK 60484. The compound was isolated from the culture filtrate of the organism and named aladapcin after its amino acid composition. Aladapcin was obtained as an amphoteric white amorphous powder with the molecular formula, C13H25N5O5. It consists of 2 mol of D-alanine and 1 mol of meso-diaminopimelic acid. From the analysis of IR, 1H NMR and FAB-MS spectra, the structure was assigned to be a tripeptide. Aladapcin enhanced host resistance against an experimental Escherichia coli infection in mice at doses ranging between 1 and 100 micrograms/kg.

Adjuvants, Immunologic↗
PubMed1990

[Clinical trial of 111In-antimyosin antibody imaging: (4). Effect of reperfusion in acute myocardial infarction].

Effects of reperfusion by intra-coronary thrombolysis (ICT) or percutaneous transluminal coronary angioplasty (PTCA) on the myocardial imaging using 111In-labeled antimyosin monoclonal antibody Fab (In-AM) were studied. Reperfusion by ICT or PTCA was done in 16 patients (reperfusion group) and recanalization was seen in 14. Positive images were obtained in 28 of 30 patients (93%) with acute myocardial infarction (onset to imaging: 9.9 +/- 9.8 days). Among the reperfusion group, one patient in whom PTCA was done early after the onset of chest pain and CPK did not elevate showed no significant uptake of radioactivity at cardiac region, while other 15 patients with elevation of CPK demonstrated positive images. Planar images (anterior, left anterior oblique 45 degrees, left lateral) were divided into 15 segments and infarct size (antimyosin-segment) was determined by sum of positive segments on each image. There were no significance between the infarct size in the reperfusion group (7.2 +/- 2.9) and that in the non-reperfusion group (6.9 +/- 3.4). Intensity of the accumulation of radioactivity in each image was classified into 5 grades by comparison with uptake of the liver (antimyosin-score). Reperfusion group demonstrated high intensity compared with non-reperfusion group (2.6 +/- 0.7 vs. 2.0 +/- 0.4; p less than 0.05). Thus, In-AM imaging may be influenced by coronary blood flow, which should be taken into consideration in the interpretation of In-AM imaging.

Adult↗
PubMed1987

Effects of captopril on cardiorenal hemodynamics in patients with severe chronic congestive heart failure.

The effects of captopril on cardiorenal function were studied in patients with chronic congestive heart failure. A single oral dose of captopril in 16 patients significantly increased cardiac indices and decreased total systemic vascular resistance. These changes were greater in subjects with higher baseline plasma renin activity (PRA). The increase in PRA and decrease in plasma aldosterone were also greater in this group. During 7 days of captopril therapy, renal plasma flow distinctly increased in 10 patients in whom renal function was followed. The increase in renal blood flow was greater in subjects with higher PRA. Simultaneous infusion of aprotinin in eight of these subjects did not affect the captopril-induced increase in renal plasma flow: these responses were the same in both PRA subgroups. The results suggest that captopril reduces total systemic vascular resistance in patients with chronic congestive heart failure through the inhibition of the renin-angiotensin system and the preferential renal vasodilating effect of captopril seems exclusively to be the sole result of this inhibition, with the kallikrein-kinin system or kinin-mediated prostaglandins not playing a major role.

Blood Pressure↗
PubMed1987

Chloropolysporins A, B and C, novel glycopeptide antibiotics from Faenia interjecta sp. nov. I. Taxonomy of producing organism.

Strain SANK 60983, an actinomycete isolated from a soil sample, was found to produce the new glycopeptide antibiotics, chloropolysporins A, B and C. Short chains of spores occur in the both aerial and substrate hyphae. meso-Diaminopimelic acid is present in the cell wall and galactose and arabinose in the whole-cell hydrolysate. Mycolic acid is absent. On the basis of the morphological, cultural and physiological characteristics, this strain was determined to be a new species of Faenia designated Faenia interjecta sp. nov. The type strain of F. interjecta Okazaki and Enokita is SANK 60983.

Anti-Bacterial Agents↗
PubMed1987

Chloropolysporins A, B and C, novel glycopeptide antibiotics from Faenia interjecta sp. nov. II. Fermentation, isolation and physico-chemical characterization.

New antibiotics, chloropolysporins A, B and C, were found in the culture broth of an actinomycete identified as Faenia interjecta sp. nov. They were isolated from the culture filtrate by column chromatography on various resinous adsorbents, followed by preparative reverse phase HPLC. Chloropolysporins A, B and C possessed all the same new aglycone composed of actinoidic acid, 3-chloro-4-hydroxyphenylglycine, N-methyl-p-hydroxyphenylglycine and vancomycinic acid. From elementary analyses and mass spectroscopic measurements, the molecular formulae of chloropolysporins A, B and C appear to be C89H99O39N8Cl3 (MW 2,008), C83H89O34N8Cl3 (MW 1,846) and C77H79O30N8Cl3 (MW 1,700), respectively. Their physico-chemical characterizations including molecular formulae revealed that chloropolysporins A, B and C were new members of glycopeptide antibiotics.

Anti-Bacterial Agents↗
PubMed1987

Chloropolysporins A, B and C, novel glycopeptide antibiotics from Faenia interjecta sp. nov. III. Structure elucidation of chloropolysporins.

Structure elucidations of chloropolysporins A, B and C were achieved mainly by chemical degradation studies. These components possessed the same pseudoaglycone in common and their structures were closely related to that of beta-avoparcin. The structures of chloropolysporins differ from that of beta-avoparcin in the presence of vancomycinic acid moiety instead of monodechlorovancomycinic acid moiety and glucose, not ristosaminylglucose, in its side chain. Chloropolysporin C was identified as derhamnosylchloropolysporin B based on its 1H NMR and mass spectral analysis and degradation studies. Two minor components, chloropolysporins D and E, were identified as the epimers of each of chloropolysporins B and C, respectively, based on their Cotton effects and retention times on reverse phase HPLC.

Anti-Bacterial Agents↗
PubMed1987

Chloropolysporins A, B and C, novel glycopeptide antibiotics from Faenia interjecta sp. nov. IV. Partially deglycosylated derivatives.

Chloropolysporins A, B and C, new members of the glycopeptide antibiotic family, were enzymatically and chemically converted to their partially deglycosylated derivatives. The alpha- and beta-avoparcins were also deglycosylated by the same method. The conversions were achieved by treatments with rhamnosidase (Naringinase) and alpha-mannosidase, and by mild acid hydrolysis.

Anti-Bacterial Agents↗
PubMed1987

Chloropolysporins A, B and C, novel glycopeptide antibiotics from Faenia interjecta sp. nov. V. Comparative studies of the biological properties.

Chloropolysporins A, B and C, as well as derivatives prepared from this group and alpha- and beta-avoparcins by enzymatic and mild acid hydrolysis, were active against Gram-positive bacteria including clinically isolated methicillin-resistant Staphylococci (MIC 0.39-6.25 micrograms/ml) and anaerobic enterobacteria (MIC 0.10-1.56 micrograms/ml). Derhamnosyl and demannosyl derivatives from both groups of antibiotics showed stronger activities than the parent compounds. The MIC and MBC values against Staphylococci were similar and were not effected by the presence of serum. Moreover, chloropolysporin C exhibited very strong synergistic effects with various beta-lactam antibiotics against methicillin-resistant strains of Staphylococcus aureus. Some of these compounds also protected mice from experimental infection with S. aureus. Acute toxicities of chloropolysporin by intravenous administration ranged from 215-290 mg/kg in mice. Chloropolysporin B as well as other glycopeptide antibiotics, showed distinctive growth promoting activity in broiler chickens.

Anti-Bacterial Agents↗
PubMed1985

A varnish to prevent etching unrestored enamel.

The prognosis of acid-etched enamel was investigated in both laboratory and clinical experiments. Acid etching produced irregularities even on the prismless layer that covers prism enamel. The irregularities produced by etching are not remineralized in vivo but are filled with organic debris. Brushing reduced the depth of the irregularities but did not eliminate them. A protective varnish against acid etching was developed. The varnish also serves as a guide to facilitate removal of excess resin beyond the cavosurface margin.

Acid Etching, Dental↗
PubMed1984

Effects of captopril on arterial and venous pressure, renal function, and humoral factors in severe chronic congestive heart failure.

The effects of captopril in several humoral factors were studied to elucidate the role of the renin-angiotensin (RA) system in arterial and venous pressures and renal function in patients with severe chronic congestive heart failure. A single oral dose of captopril in 20 subjects reduced mean arterial blood pressure from 77 to 67 mm Hg; this decrease correlated with baseline plasma renin activity (PRA). The increase in PRA and the decrease in plasma aldosterone levels after captopril were much greater in subjects with higher PRA. Plasma norepinephrine (NE) levels decreased, while those of epinephrine did not change. Peripheral venous pressure declined from 107 to 77 mm H2O; this decrease correlated with the change in NE levels. During 7-day captopril therapy, urine volume and sodium excretion increased (1145 to 1136 ml/day and 76 to 94 mEq/day) in 11 subjects in whom renal function was followed. Renal plasma flow (RPF) rose from 237 to 364 ml/min, while glomerular filtration rate did not change; the filtration fraction decreased from 32% to 23%. Simultaneous infusion of aprotinin in six of the subjects did not affect the captopril-induced increase in RPF, despite the suppression of plasma bradykinin levels. These results suggest that captopril reduces arterial blood pressure in patients with high PRA through inhibition of the RA system and dilates veins by attenuation of sympathetic nervous activity. Increased RPF and urinary sodium excretion induced by captopril might result from inhibition of the RA system; the kallikrein-kinin system or bradykinin-mediated prostaglandins do not appear to play a major role.

Adult↗