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M Tada

Publications and source records attributed to M Tada.

695 records · Page 39Linked to original sources
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Decreased and abnormal left ventricular filling in acute heart failure: role of pericardial constraint and its mechanism.

Pericardial constraining force is minimal in normal hearts; however, it is considered to be prominent in moderate to severe heart failure. Thus, effects of the pericardium on pulsed Doppler transmitral flow velocity pattern were examined in 17 dogs with acute left ventricular dysfunction. Left ventricular dysfunction with left ventricular end-diastolic pressure > or = 15 mm Hg was produced by injection of microspheres into the left coronary artery. Transmitral flow velocity pattern, left atrial and left ventricular diameters, and high-fidelity left atrial and left ventricular pressures were recorded before and after pericardiectomy. In five of the 17 dogs, mitral regurgitation with giant "v" wave of left atrial pressure occurred with reductions of left ventricular systolic pressure and peak rate of the left ventricular pressure fall (dP/dt) after pericardiectomy. In the other 12 dogs, peak early and late diastolic filling velocities increased with a decrease in left ventricular minimal pressure and increases in left arterial and left ventricular diameters and left atrial and left ventricular compliance after pericardiectomy. In these 12 dogs, left atrial to left ventricular crossover pressure, left ventricular end-diastolic pressure, and references for left ventricular relaxation did not change after pericardiectomy. Thus the release from pericardial constraining force in severe heart failure may increase chamber compliance of the left ventricle and left atrium and, in turn, increase peak early and late diastolic filling velocities through an increment in forward transmitral pressure gradient. Increased pericardial constraining force is a possible cause limiting left ventricular filling and hence cardiac output in heart failure.

Acute Disease↗
PubMedDate not supplied

Peak early diastolic filling velocity may decrease with preload augmentation: effect of concomitant increase in the rate of left atrial pressure drop in early diastole.

Doppler-determined transmitral flow velocity pattern has been shown to depend on transmitral pressure gradient, and left atrial (LA) pressure has been considered to be important in determining transmitral pressure gradient in early diastole and peak early diastolic filling velocity (E). In recent studies in human beings, however, it was proved that E did not necessarily change with LA pressure. This may be because concomitant changes in other factors masked the effect of LA pressure. To investigate the relation between transmitral flow velocity pattern and hemodynamic parameters during preload intervention over the wide range of LA pressure, pulsed Doppler transmitral flow velocity pattern and high-fidelity LA and left ventricular (LV) pressures were simultaneously recorded during rapid volume loading to the LA. Data at three stages, at control, at moderate volume loading (the median LA-to-LV crossover pressure during the volume loading), and at advanced volume loading (the maximal crossover pressure during the volume loading), were compared with one another in 11 dogs. A mean value of E increased with the crossover pressure up to moderate volume loading but did not further increase at advanced volume loading. In the data pooled from all experimental stages in all dogs, the changes in E did not correlate with those in the crossover pressure, but correlated weakly with those in the difference between the crossover pressure and LV minimum pressure (r = 0.45, p < 0.05). E decreased at advanced volume loading in three of 11 dogs with a steep LA pressure drop in early diastole although the changes in the difference between the crossover pressure and LV minimum pressure in the three dogs were similar to those in the other eight dogs. The changes in a rate of LA pressure drop in early diastole associated with advanced volume loading inversely correlated with those in E (r = -0.79, p < 0.01). Thus, E may decrease with an extreme increase in LA pressure; this change may be due to an associated increase in a rate of LA pressure drop in early diastole. This finding suggests that at high LA pressure the increased rate of LA pressure drop in early diastole appears to decrease LV filling and hence to reduce stroke volume.

Animals↗
PubMedDate not supplied

Diagnostic ERCP.

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Biliary Tract Neoplasms↗
PubMedDate not supplied

Rathke cleft cyst: MR and biomedical analysis of cyst content.

PURPOSE: At least one type of Rathke cleft cyst has unique MR findings, specifically, high intensity on T1-weighted images and iso- to low intensity on T2-weighted images relative to white matter. To clarify the influence of cyst content on MR images, we analyzed the cyst content by biomedical methods after surgical removal. METHOD: We studied five patients diagnosed with Rathke cleft cyst, whose MR images showed high intensity on T1-weighted images and iso- to low intensity on T2-weighted images. After surgery, total protein and cholesterol levels were quantified, and correlations of protein and cholesterol content with T1 and T2 signal intensities were performed in vitro. RESULTS: All five cysts had very high concentrations of protein (11,700-26,600 mg/dl, mean 17,940 mg/dl) with nearly no cholesterol (at most 2.0 mg/dl). Along with increases in protein concentration in vitro, the signal intensity of T1-weighted images increased, while that of T2-weighted images decreased. In contrast, the cholesterol concentration sequence influenced the signal intensity of neither T1- nor T2-weighted images. CONCLUSION: The unique MR finding of Rathke cleft cysts--high signal intensity on T1-weighted images and low signal intensity on T2-weighted images--might depend mainly on protein concentration, not on cholesterol.

Adult↗
PubMedDate not supplied

Species and organ differences in DNA adduct formation and repair after treatment with 4-hydroxyaminoquinoline 1-oxide.

4-Hydroxyaminoquinoline 1-oxide (4HAQO) demonstrates obvious organotropic and species specificity in its carcinogenesis and the present investigation concerns 4HAQO DNA adduct formation and repair as studied in various organs of four animal species (rats, mice, guinea pigs and hamsters). Three hours after an iv injection of 10 mg per kg body weight of tritium-labeled 4HAQO, the major organs were removed and used for assessment of label incorporation in the DNA. The results showed that the DNA binding levels generally correlated well with the reported species and organ specificity of 4HAQO tumorigenesis. For example, rats showed highest DNA binding in the pancreas and kidney, major target organs. The levels of DNA binding in the liver were invariably low in all 4 animal species, in agreement with the lack of hepatocarcinogenicity associated with 4HAQO exposure. A clear relationship between DNA adduct formation and carcinogen dose was also found after treatment of mice with 4HAQO at doses of 1, 5, 10 and 20 mg per kg body weight in all tissues (pancreas, kidney and lung) except for the liver. Comparison of DNA repair processes in rats, a highly susceptible species, and hamsters, a resistant species in terms of 4HAQO carcinogenicity, revealed highest formation and slowest removal of adducts in the target organs of the rat. In the hamster organs and the rat lung and liver, DNA adduct formation was generally low and in the case of elevation in the initial phase, quickly removed.

4-Hydroxyaminoquinoline-1-oxide↗
PubMedDate not supplied

Endoscopic hemostasis for bleeding peptic ulcer using a hemostatic clip or pure ethanol injection.

BACKGROUND/AIMS: Endoscopic hemostasis is frequently chosen as the treatment of first choice for bleeding peptic ulcers. We retrospectively compared the hemostatic effects of hemoclips and endoscopic ethanol injection in patients with bleeding gastric and duodenal ulcers. METHODOLOGY: The subjects were 149 patients with 156 bleeding peptic ulcer lesions who were treated by endoscopic hemostasis, comprising 127 gastric ulcers and 29 duodenal ulcers. Hemoclips were used for 68 lesions (hemoclip group) and ethanol injection was done for 88 lesions (ethanol group). RESULTS: The hemostasis rates were 98.5% for the hemoclip group and 92.0% for the ethanol group. There was no significant difference in hemostatic effect between these two methods. All patients with unsuccessful hemostasis had a visible vessel larger than 2.0 mm in diameter and/or concomitant disease. CONCLUSIONS: The results suggest that these two endoscopic hemostatic methods are both highly effective. The presence of a large visible vessel may be predictive of unsuccessful hemostasis.

Adult↗
PubMedDate not supplied

Significance of the membrane protein phospholamban in cyclic AMP-mediated regulation of calcium transport by sarcoplasmic reticulum.

Phospholamban (molecular weight = 22,000), which serves as a regulator of Ca transport ATPase (molecular weight = 100,000) of cardiac sarcoplasmic reticulum (SR), becomes resistant to tryptic digestion upon phosphorylation by cAMP-dependent protein kinase (PK). The protective effect of phosphorylation is accompanied by persistence of the PK-induced stimulation of Ca transport. These findings indicate that structural alteration of phospholamban upon phosphorylation is closely associated with changes in the functional properties of cardiac SR. SR from fast-contracting skeletal muscle of rabbit does not contain a 22,000-dalton substrate for cAMP-dependent PK, nor is Ca transport stimulated by exogenous PK. SR preparation isolated from slow-contracting skeletal muscle of rabbit and dog contains phospholamban, and Ca transport was found to be increased by exogenous cAMP-dependent PK. In view of the distribution of phospholamban among different types of muscle, a hypothesis is presented to explain the relaxation-promoting effects of catecholamines in cardiac and slow-contracting skeletal muscle in which phospholamban is found. This may also account for the absence of a similar effect of catecholamines in fast-contracting skeletal muscle, which does not contain a similar substrate for PK.

Adenosine Triphosphatases↗
PubMedDate not supplied

Effect of protein kinase modulator on cAMP-dependent protein kinase-catalyzed phosphorylation of phospholamban and stimulation of calcium transport in cardiac sarcoplasmic reticulum.

The heat-stable protein (protein kinase modulator), partially purified from fresh bovine heart, possessed the ability to inhibit and stimulate adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase and guanosine 3':5'-monophosphate (cGMP)-dependent protein kinase activities, respectively. The inhibitory activity of protein kinase modulator on cAMP-dependent protein kinase was abolished almost completely by trypsin treatment, while the ability to stimulate cGMP-dependent protein kinase activity was resistant to trypsin. Fractionation by a linear potassium phosphate gradient on DEAE-cellulose column did not clearly separate both activities. Phosphorylation of cardiac microsomal component, "phospholamban" (molecular weight = 22,000), was inhibited almost completely by the saturating amounts of protein kinase modulator. This inhibition of phospholamban phosphorylation by protein kinase modulator was accompanied by a decreased Ca uptake rate that had been stimulated by cAMP-dependent protein kinase. These findings indicate that protein kinase modulator is functional in controlling the cAMP-dependent protein kinase-catalyzed phosphorylation of phospholamban and the rate of calcium transport, lending further support for the previously proposed mechanism, in which phospholamban is assumed to serve as a regulator of calcium transport in cardiac sarcoplasmic reticulum.

Animals↗
PubMedDate not supplied

[Early gastric cancer staging by radiology, endoscopy, trans-endoscopic ultrasonography and its anatomo-pathological correlation].

Early gastric cancer detection is still in its more elementary step in the western hemisphere, while in Japan gastric cancer is detected mainly in its early stage. The aim of this article is to analyze the Japanese method for early gastric cancer detection and staging, by sketch of certain morphologic criterions and a report of a typical case. In our case the lesion's staging was predicted as submucosal by means of endoscopy and double contrast roentgenography. Endoscopic ultrasonography complemented the analysis. The standard anatomopathological work up for early gastric cancer in Japan is also analysed. By this former method the accuracy of the initial staging by endoscopy, and radiologic means was ensured. By a correct early gastric cancer diagnosis and staging a better selection of the surgical strategy and survival can be achieved.

Adenocarcinoma↗
PubMedDate not supplied

Neuroepithelial (colloid) cyst of the cerebellar vermis containing a xanthogranuloma.

A case of a neuroepithelial cyst of the cerebellar vermis is presented. The cyst contained a viscous fluid and a xanthogranulomatous nodule. The fluid showed high signal on T1- and low signal on T2-weighted MR images. The xanthogranuloma showed mixed intensities with partial contrast enhancement. The correlation of the cyst contents and MR signals is discussed.

Adult↗