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Biomedical subjects

T Uchida

Publications and source records attributed to T Uchida.

At least 1,261 records · Page 70Linked to original sources
PubMed1981

[Exercise echocardiography: interventricular septal thickness and motion in patients with effort angina during ergometer exercise (author's transl)].

To detect abnormal interventricular septal (IVS) motion during exercise-induced ischemia, ergometer exercise echocardiography was performed using a specially devised transducer in 12 patients (pts) with effort angina (left anterior descending artery disease) and 10 normal subjects (N) at rest, and during exercise and recovery. During exercise, percent systolic IVS thickening (% delta T) and IVS excursion (Ex) increased from 52 +/- 13% at rest to 73 +/- 19% and from 7.0 /- 1.3 mm at rest to 10.6 +/- 1.9 mm, respectively, in N, and also from 52 +/- 23% to 67 +/- 36% and from 7.3 +/- 1.9 mm to 9.7 +/- 2.1 mm in all of 3 pts with distal left anterior descending artery disease. On the other hand, in 9 pts with proximal left anterior descending artery disease, % delta T and Ex during exercise decreased from 41 +/- 17+ at rest to 26 +/- 25% and from 7.7 +/- 1.2 mm to 5.1 +/- 4.6 mm. The late systolic wall thickening of IVS was observed during peak exercise in 2 of the 9 pts, one of whom exhibited systolic IVS thinning and a decrease in diastolic thickness (from 6 mm to 4.5 mm). In 5 pts with IVS asynergy during exercise diastolic IVS thickness increased maximally from 10.2 +/- 3.3 mm at rest to 11.4 +/- 3.5 mm during recovery (reactive hyperemia). Exercise echocardiography is useful to predict the location of left anterior descending artery disease and to evaluate IVS performance during exercise-induced ischemia.

Adult↗
PubMed1981

[The effect of the Valsalva and Müller maneuvers on right and left atrial dimensions in man studied by esophageal echocardiography (author's transl)].

The effect of the Valsalva (V) and Müller maneuvers (M) on the right and left atrial dimensions was evaluated by esophageal echocardiography in 8 normal male subjects. During V and M, the right atrial free wall (RAW), interatrial septum (IAS) and left atrial posterior wall were recorded by esophageal echocardiography simultaneously with intraairway pressure (Paw). Right (RAD) and left atrial dimensions (LAD) at atrial end-diastolic were measured at various phases during each maneuver. Mean expiratory effort of +40 mmHg Paw in V and mean inspiratory effort of -40 mmHg Paw in M were maintained for about 10 sec. Both atrial dimensions changed significantly during each maneuver. RAD began to decrease just after the onset of V, while LAD changed little during this phase, after which began to decrease progressively. The leftward displacement of IAS with the simultaneous outward displacement of RAW resulted in an increase of RAD and a decrease of LAD just after the onset of M and the release of V. LAD remained higher than resting value from the second (2--4 sec after the onset) to late phase (just before the release) during M. RAD decreased just after the release of M. Thus, esophageal echocardiography was useful to evaluate both atrial dimensions during V and M.

Adult↗
PubMed1981

[Significance of non-invasive parameter (PSP/ESVI) in assessing left ventricular contractility (author's transl)].

Since myocardial pump function is affected by preload or afterload, it is difficult to assess left ventricular (LV) contractility independently from these in clinical cardiology. In this study, we performed inotropic intervention by isoproterenol or propranolol, and changed afterload by angiotensin or nitroprusside, to estimate the usefulness of peak systolic pressure/end-systolic volume index (PSP/ESVI) as a parameter of LV contractility. The data were obtained by cuff method or catheter-tip manometer and echocardiography. We calculated PSP/ESVI in various heart diseases, and results were analyzed for a significant change using the t test. Ejection fraction, mean VCF (mVCF) were calculated simultaneously, and compared with PSP/ESVI. The results were as follows: 1) PSP/ESVI ratio significantly reflected inotropic intervention with isoproterenol and propranolol. 2) PSP/ESVI ratio was less affected by the change of peak systolic pressure than EF or mVCF. 3) There was a significant difference in PSP/ESVI among congestive cardiomyopathy, valvular heart diseases and normal controls. 4) There was also a significant difference in PSP/ESVI between patients of NYHA I and those of NYHA II--IV. 5) PSP/ESVI ratio, measured by non-invasive method, was thought to be a useful parameter to assess LV contractility.

Adolescent↗
PubMed1981

Analysis of methods to construct nomograms in uroflow studies.

A Monte Carlo simulation study to compare the effect of population form on three methods of nomogram construction was performed by taking 2000 random samples of size 5, 20, 50, 100, and 200 from populations with known percentiles. The 10th percentile was estimated by each of the three construction procedures. The three procedures compared were the upper 95 per cent nonparametric tolerance limit technique, the usual percentile approach, and a method which assumes a Gaussian (normal) distribution. Tenth percentile nomograms, classified by volume voided, were calculated by each of the three procedures for maximum flow rate determinations from 356 normal males of ages 1 to 12 years with body surface areas less than 1.1 m2. Nomograms of the three methods are validated with evaluations from two other groups of male children consisting of known abnormals with radiologically proven urethral obstructions and known normals who had repeated at home uroflow rates. The nonparametric tolerance limit approach gives conservative estimates and is superior in all cases from the standpoint of reducing false-negative results.

Child↗
PubMed1981

[Exercise echocardiography: relationship between interventricular septal wall dynamics and electrocardiographic changes during ischemia (author's transl)].

The relationship between interventricular septal (IVS) wall motion assessed by the echocardiogram and surface electrocardiogram was investigated in 11 patients (pts) with proximal left anterior descending coronary artery disease (LADd) during ergometer exercise. A specially devises transducer was used to obtain the echocardiograms. During exercise, 6 pts had transient ST segment depression (Group 1), whereas 5 pts had transient ST segment elevation (Group 2). During exercise-induced ischemia, the ST segment depression occurred prior to abnormal wall motion in Group 1, and lasted longer than the latter. On the other hand, the ST segment elevation was preceded by abnormal wall motion in Group 2, and returned to the control earlier than the latter. In conclusion, exercise echocardiography is useful to assess the relationship between interventricular wall dynamics and electrocardiographic changes during ischemia.

Angina Pectoris↗
PubMed1980

Nuclease TT1 from Thermus thermophilus HB8 has an endonuclease activity preferential to circular DNAs.

Homogeneously purified nuclease TT1 from Thermus thermophilus HB8 is known as an exonuclease to produce 5'-mononucleotides. Besides the exonuclease activity, nuclease TT1 also possesses endonuclease activity preferential to superhelical (form I) and single-stranded circular DNA. Although the rate of cleavage is slower than that of form I, covalently closed circular DNA (form I') is also cleaved. Form I DNA was nicked to yield relaxed circles (form II) first, and was then nicked at the opposite site to yield unit length linear DNA (form III) which was subsequently hydrolyzed to 5'-mononucleotides exonucleolytically. Both endo- and exo-nuclease activities co-migrate on polyacrylamide gels. The general properties of the endonuclease activity are very similar to those of the exonuclease activity. The temperature optimum for endonuclease activity was 85 degrees C. The pH-optimum was in pH-range from 7.5-9.1. The enzyme was active over a wide range of Mg2+ concentrations (2.5-125 mM), and was inhibited by EDTA. A linear substrate such as (dT)8 was a competitive inhibitor for this endonuclease activity.

Binding Sites↗
PubMed1980

A new prolyl hydroxylase acting on poly-L-proline, from suspension cultured cells of Vinca rosea.

A new prolyl hydroxylase having a novel substrate specificity was isolated from the suspension-cultured cells of Vinca rosea. This enzyme was solubilized with 0.05 M Tris-HCl buffer (pH 7.4) containing 0.1% Triton X-100, 0.3 M NaCl and 0.5 mM beta-mercaptoethanol from the membrane fractions of the cells, and was partially purified by (NH4)2SO4 fractionation and DEAE-Sephadex A-50 column chromatography. The enzyme preparation was found to require O2, Fe2+, ascorbate, alpha-ketoglutarate and poly-L-proline to attain maximum activity. The plant enzyme does not hydroxylate free proline and di-, tri- and tetra-L-proline, but hydroxylates octa-L-proline and poly-L-proline (Mr greater than 2000). Model peptides of unhydroxylated collagen, (Pro-Pro-Gly)5 and (Pro-Pro-Gly)10 are poor substrates for the plant enzyme. This means that the plant enzyme has a novel substrate specificity in regard to peptidyl substrate, and this differs from vertebrate prolyl hydroxylase, proline,2-oxoglutarate dioxygenase (prolyl-glycyl-peptide, 2-oxoglutarate: oxygen oxidoreductase, EC 1.14.11.2).

Ascorbic Acid↗
PubMed1980

Hybrid toxin of the A chain of ricin toxin and a subunit of Wistaria floribunda lectin. Possible importance of the hydrophobic region for entry of toxin into the cell.

About 27% or more of the total amount of the A chain of ricin toxin associated with lipid vesicles, whereas less than 1.4% of the A fragment of diphtheria toxin associated with the vesicles under the various conditions tested. Two hybrid toxins were constituted from a subunit of Wistaria floribunda lectin and the A fragment of diphtheria toxin (Uchida, Y., Yamaizumi, M., Mekada, E., Okada, Y., Tsuda, M., Kurokawa, T., and Sugino, Y. (1978) J. Biol. Chem. 253, 6307-6310) and the A chain of ricin toxin, which has higher affinity to lipids than the A fragment of diphtheria toxin. The toxicity of the hybrid of the A chain of ricin and the subunit of W. floribunda lectin, estimated by measuring the inhibition of protein synthesis of cultured cells, was about 100 to 200 times that of the hybrid of the A fragment of diphtheria and the subunit of W. floribunda lectin. These findings may suggest that a hydrophobic region of the toxin is essential for entry of toxin into the cells.

Amino Acid Sequence↗