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Biomedical subjects

K Tsuchihashi

Publications and source records attributed to K Tsuchihashi.

104 records · Page 6Linked to original sources
PubMed1984

Electrocardiographic abnormalities in cerebrovascular accidents.

In order to assess the relationship of electrocardiographic (ECG) changes in acute cerebrovascular accidents (CVA) to the locations of the cerebral lesions, ECG records and brain computerized tomographic (CT) scans which were taken within 48 hours of CVA onset were examined in 39 patients without heart disease and/or treatment with cardiovascular drugs. The ECG was normal in 25% (3/12) of basal ganglial CVA, 22% (2/9) of frontal CVA and 36% (4/11) of temporo-parietal CVA. Nonspecific ST-T changes occurred in basal ganglial CVA (25%), frontal CVA (22%), temporo-parietal CVA (18%) and in the other categories of CVA locations. Corrected QT interval (QTc) elongation was observed not only in frontal (22%), but also in basal ganglial CVA (25%), temporo-parietal CVA (36%) and cerebellar CVA (50%). There were no ECG changes specific to a particular CVA location. These findings suggest that widely distributed neurons and pathways within the central nervous system may influence ECG.

Adult↗
PubMed1983

Lysine residues located on the surface of human plasma high-density lipoprotein particles.

Normal human plasma high-density lipoprotein (HDL) was reacted with trinitrobenzenesulfonate (TNBS). The time course of the reaction of intact HDL in phosphate buffer (pH 8.6) at 20 degrees C was biphasic, having a transition plateau. Both the first phase and the second phase reactions followed pseudo-first-order kinetics, and their rate constants at 20 degrees C were 4.6 X 10(-2) and 4.9 X 10(-3)/min, respectively. The activation energies of these reactions estimated from Arrhenius plots were 22.9 kcal/mol for the first phase and 20.9 kcal/mol for the second phase. The frequency factors, however, were markedly different from each other. On the other hand, the biphasic kinetic curves could not be observed when HDL was reacted with TNBS after delipidation, heat denaturation or Triton X-100 treatment. The rate constants for TNBS reactions of apolipoprotein HDL and heat-denatured HDL were essentially the same, 1.0 X 10(-2)/min, and those for HDL and apolipoprotein HDL in Triton X-100 were also the same, 3.57 X 10(-3)/min at 20 degrees C. Furthermore, fluorodinitrobenzene (FDNB), a typical penetrating chemical probe, reacted with intact HDL, indicating a nonbiphasic nature. These observations suggest that two reacting classes of lysine residues in intact HDL particles can be distinguished by the biphasic TNBS reaction, and that at the first phase of the reaction TNBS modifies selectively the accessible lysine residues exposed to surrounding aqueous environments. On this basis, intact HDL3 was reacted with TNBS at 20 degrees C for 80 min and it could be considered that at least 10 of 22 primary amino groups of apolipoprotein A-I and 10 of 18 lysine residues of apolipoprotein A-II were exposed on the surface of HDL3 particles.

Chemical Phenomena↗
PubMed1979

Biologically active polycycloalkanes. 6. Antiviral 1-tricyclo[4.3.1.1 2,5]undecyl derivatives.

Functionalization reactions via cationic intermediates of tricyclo[4.3.1.1 2,5]undecane (2) were investigated to prepare derivatives with potential antiviral activities. Bromination of 2 took place regiospecifically at C-1, and the resulted bromide 5 was converted into the hydroxide 9, the carboxylic acid 12, and the amine 22, from which were synthesized a variety of secondary derivatives, including homologous esters 10 and 20, amides 14 and 19, carbamates 24, and ureas 17 and 25. The hydroxide 9, the acid 12, and the acetamide 21 were also obtainable directly from tricyclo[5.2.1.0 2,6]dec-endo-2-ylcarbinol (1), the precursor for the synthesis of the hydrocarbon 2. Success in these functionalization-rearrangements was attributed to the inability of the intermediate 2-1-yl cation (2+) for further skeletal isomerizations. Among the 1-substituted derivatives of 2 prepared, the amine hydrochlorides (16 and 23), a few esters (20b and 20d), and some N-alkylamides (19c, 19d, and 19e) exhibited marked antiviral activities as compared to amantadine hydrochloride, when tested in vitro on a monolayer culture of chick embryo fibroblasts against Newcastle disease virus.

Animals↗
PubMedDate not supplied

Cardiac death prediction and impaired cardiac sympathetic innervation assessed by MIBG in patients with failing and nonfailing hearts.

BACKGROUND: Although cardiac sympathetic nerve dysfunction is related to poor clinical outcome, a critical sympathetic dysfunction level for predicting cardiac death is still unclear. The current study was designed to investigate which indices derived from metaiodobenzylguanidine (MIBG) imaging have prognostic value compared with clinical and cardiac function variables, and to determine the threshold of cardiac MIBG activity for identifying patients likely to suffer cardiac death in both failing and nonfailing hearts. METHODS AND RESULTS: Myocardial I-123-MIBG activity was quantified as a heart-to-mediastinum ratio in 414 consecutive patients, 173 (42%) of whom had symptomatic heart failure. After cardiac function measurements, patients were followed up with an end-point of cardiac or noncardiac death. During a mean follow-up period of 22 months, 37 cardiac deaths occurred: 23 resulted from heart failure, 9 were sudden cardiac deaths, and 5 were fatal myocardial infarctions. Multivariate analysis using the Wald chi2 and the Cox proportional hazard model revealed that late heart-to-mediastinum ratio, the use of nitrates, early heart-to-mediastinum ratio, and left ventricular ejection fraction were independent predictors of cardiac death; late heart-to-mediastinum ratio, New York Heart Association (NYHA) class, the presence of previous myocardial infarction, and age were independent predictors of heart failure and sudden cardiac death. Late heart-to-mediastinum ratio was the most powerful predictor of overall cardiac death among the variables. The Kaplan-Meier analysis showed that a late heart-to-mediastinum ratio of 1.74 or less, age greater than 60 years, the presence of myocardial infarction, and NYHA functional class 3 or 4 strongly indicated poor clinical outcomes. Furthermore, the more powerful incremental prognostic values were obtained by using MIBG imaging in combination with conventional clinical variables. CONCLUSIONS: Impaired cardiac sympathetic innervation assessed by MIBG activity has the greatest potential for predicting cardiac death and may be useful for identifying a threshold level for selecting patients at risk for death by heart failure, sudden cardiac death, and fatal myocardial infarction.

3-Iodobenzylguanidine↗
PubMedDate not supplied

Two- and three-dimensional assessments of myocardial perfusion and function by using technetium-99m sestamibi gated SPECT with a combination of count- and image-based techniques.

BACKGROUND: Although the myocardial gated single photon emission computed tomography (SPECT) technique makes it possible to assess concurrent myocardial perfusion and function, quantitative methods for analyzing and displaying gated SPECT data in 2- and 3-dimensional presentations for regional and global cardiac assessment have not been established. METHODS AND RESULTS: We have developed an automated quantitative method for assessing perfusion and function by means of technetium-99m sestamibi gated SPECT with a computerized technique combining count-based and image-based methods. We have examined its validity in 91 patients by comparing its results with those of conventional techniques: contrast left ventriculography and radionuclide angiocardiography. In addition to color-scale displays of regional function, simultaneous 3-dimensional presentations of regional wall motion and perfusion have been produced. High reproducibility of gated SPECT analysis with this algorithm was demonstrated; interoperator errors (%CV) were 2.6% to 5.5%, and good intraobserver reproducibility was confirmed by means of high correlation coefficients (0.954 to 0.989). Left ventricular volumes assessed by means of contrast left ventriculography and by means of the gated SPECT technique showed significant correlations (left ventricular end-diastolic volume, y = 1.01x - 9.7, r = 0.845, P<.001, standard errors of the estimate [SEE] = 14 mL; left ventricular end-systolic volume, y = 1.03x - 1.4, r = 0.902, P<.001, SEE = 6 mL). Left ventricular ejection fraction determined by means of gated SPECT with the new algorithm closely correlated with that determined by means of radionuclide ventriculography (y = 1.05x - 0.6, r = 0.891, P<.001, SEE = 3 %). These parameters quantified by means of the present method correlated closely with those derived from the QGS program (r = 0.926 to 0.987). CONCLUSION: In comparison with conventional techniques, myocardial gated SPECT with automated quantitative analysis provides accurate and reproducible data for global and regional function. Quantitative concurrent assessment of myocardial perfusion and function by using 2-and 3-dimensional representations appears to be superior to other modalities and to contribute to nuclear cardiology practice.

Adult↗
PubMedDate not supplied

Role of renal dopaminergic activity on renal sodium-water metabolism in congestive heart failure.

1. The role of the renal dopaminergic system in water-sodium metabolism in heart failure remains unclear. 2. In this study, the urinary free dopamine excretion (uDA), delivery of L-dopa to renal proximal tubules (plasma L-dopa x creatinine clearance (Ccr)), and the production of dopamine in the kidney [uDA/(plasma L-dopa x Ccr)] were investigated in patients with congestive heart failure (n = 30) and in normal controls (n = 12). In both groups, endogenous Ccr, urinary excretion of sodium (UNaV), fractional excretion of sodium (FENa), plasma noradrenaline concentration (pNA) and plasma L-dopa concentration were also estimated. 3. uDA, plasma L-dopa, delivery of L-dopa and dopamine production in the kidney showed successively lower values in congestive heart failure with progression in NYHA functional class. 4. UNaV (r = 0.458, P < 0.05) and Ccr (r = 0.539, P < 0.01) positively correlated with uDA. Linear correlations were found between left ventricular ejection fraction and uDA (r = 0.574, P < 0.01), pNA (r = -0.495, P < 0.01) or plasma L-dopa (r = 0.423, P < 0.05). 5. From these findings, it was suggested that (i) uDA was clearly suppressed in patients with CHF, and (ii) the possible mechanisms of its suppression might be due to decrease of delivery of L-dopa into the proximal tubules and suppressed production of dopamine from L-dopa in the kidney.

Adult↗
PubMedDate not supplied

Detection of cardiac calcinosis in hemodialysis patients by whole-body scintigraphy with 99m-technetium methylene diphosphonate.

A noninvasive method for the diagnosis of cardiac calcinosis, a life-threatening complication in hemodialysis patients with end-stage renal disease (ESRD), has not, as yet, been firmly established. We tested whether whole body scanning with 99m-technetium methylene diphosphonate (MDP) might visualize cardiac calcinosis. In 19 consecutive chronic hemodialysis ESRD patients (13 males and 6 females, aged 40-81, mean 63 +/- 8 years) with cardiovascular disease [mitral annular calcinosis and/or calcified aortic valve (n = 4), hemodialysis cardiomyopathy (n = 1), coronary artery disease (n = 9) and peripheral artery atherosclerotic disease (n = 6)], MDP uptake in the heart was compared to that in 7 non-ESRD controls with hyperparathyroidism due to adenoma. Cardiac and lung field MDP uptake was confirmed in only 3 (16%) and 5 (26%) of the 19 ESRD subjects, respectively, but was absent in controls. Positive cardiac uptake was related to cardiac calcified complications (mobile intracardiac calcinosis, myocardial calcinosis and mitral annular calcification) and the duration of hemodialysis (p = 0.015). While it was statistically insignificant, subjects showing MDP uptake were elder and had higher serum Ca or Ca x P product and lower intact parathyroid hormone levels. These results suggest that cardiac calcinosis in ESRD patients can be detected noninvasively by myocardial scintigraphy with 99m-technetium MDP.

Adult↗
PubMedDate not supplied

A case of a right coronary artery to left ventricle fistula observed over twenty years.

Since the natural history of a coronary artery to left ventricle fistula is not well known, a case of such a fistula in 36-year-old female patient, followed for 20 years is presented. Two-dimensional echocardiography performed as a follow-up examination revealed enlargement of the right coronary artery and the right Valsalva sinus. Two-dimensional color flow mapping showed the jet flow to the apex from the base of the left ventricle only during the diastolic phase. An aortogram confirmed that enlargement of both the right coronary artery and the right Valsalva sinus had occurred during the 20 years. The shunt flow ratio was about 50%. The Symbas procedure, closing of the coronary artery fistula by arteriotomy directly over the site of the fistula, was performed with the aid of extracorporeal circulation. Our findings indicate that enlargement of the shunted coronary artery and its Valsalva sinus can occur gradually where there is a relatively large shunt flow. Therefore, early surgical treatment is recommended in cases like this one.

Adult↗
PubMedDate not supplied

[Fatty acid metabolic and perfusion abnormalities in hypertrophied myocardium assessed by dual tracer tomography using thallium-201 and iodine-123-beta-methylpentadecanoic acid].

Fatty acid metabolic and perfusion abnormalities associated with cardiac hypertrophy were investigated using dual tracer tomography with thallium and a cardiac metabolic tracer, 15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (BMIPP), in eight patients with hypertrophic cardiomyopathy (HCM) and in three with hypertension (HT). Thallium and BMIPP uptakes were scored and analyzed in 143 segments (13/heart) by comparison with the left ventricular wall thickness measured by two-dimensional echocardiography. Complete agreement of both scores in HT patients was significantly higher than that in HCM patients (64% vs 24%, p < 0.001), while a lower BMIPP uptake compared to that of thallium (mismatching) was observed more frequently in HCM than in HT patients (65% vs 31%, p < 0.001). The wall thickness significantly (p < 0.005) correlated with BMIPP uptake score. HCM patients showed a low BMIPP uptake in 22 hypertrophic segments (59%) and 15 non-hypertrophic segments (41%), and reduced BMIPP uptake in 29% hypertrophic segments, while HT patients showed just five segments with decreased BMIPP uptake of which 4 were non-hypertrophic and only one hypertrophic. The left ventricular ejection fraction assessed by radionuclide ventriculography was normal and no regional wall motion abnormality was detected in any patient by echocardiographic and scintigraphic studies. Metabolic abnormalities detected by the iodine-123-beta-methyl fatty acid analog in hypertrophic cardiomyopathy may be independent of thallium myocardial perfusion, regional wall motion, or the magnitude of cardiac hypertrophy, suggesting that fatty acid imaging may be useful in investigating the pathogenesis and subclinical abnormality of hypertrophic cardiomyopathy, and differentiation from secondary, induced cardiac hypertrophy.

Adult↗