Significance of Tei-index alterations induced by acute preload reduction with hemodialysis.

AIM: The load dependence of Tei-index, an index to estimate combined systolic and diastolic ventricular functions, remains controversial. Moreover, its significance in the setting of acute preload reduction including hemodialysis (HD) remains unknown. Therefore, we examined the significance of the Tei-index in HD patients. PATIENTS AND METHODS: Doppler echocardiographic parameters of 42 patients with normal left ventricular ejection fraction (LVEF) were evaluated before and after HD. Based on the index of body water excess calculated using a Crit-Line monitor, the patients were assigned to Group A (normal hydration approximately overhydration) and Group B (risk of pulmonary congestion). RESULTS: Group A was younger and had a shorter isovolumic relaxation time (IRT) than Group B before HD. Hemodialysis significantly increased the Tei-index of Group A, which was derived from prolonging IRT and isovolumic contraction time and shortening the ejection time without changing LVEF. Changes in the Tei-index (DeltaTei-index) significantly correlated with the rate at which blood volume decreased. They were derived from graphs generated using the Crit-Line monitor. Furthermore, the DeltaTei-index inversely correlated with the Tei-index before HD. CONCLUSION: These findings suggest that the Tei-index is preload-dependent, which is related to changes in volume and speed. Thus, the Tei-index should be cautiously interpreted according to various hemodynamic situations. However, the correlation between the DeltaTei-index and the Tei-index before HD implies that the latter could be a good indicator of effective fluid removal by HD.

Cardiac function in dialysis patients evaluated by Doppler echocardiography and its relation to intradialytic hypotension: a new index combining systolic and diastolic function.

AIM, PATIENTS AND METHODS: Cardiac function of 40 patients on maintenance dialysis was examined using a new Doppler index combining systolic and diastolic function. Immediately before dialysis, ultrasonic pulsed Doppler was used to measure right and left ventricular inflow and outflow waveforms. The sum of the isovolumetric contraction time (ICT) and isovolumetric relaxation time (IRT) was calculated by subtracting the ejection time from the interval between the end of an inflow waveform and the start of the next inflow waveform. The new index was obtained by dividing the sum of the two isovolumetric times by the ejection time. Cardiac function was evaluated in dialysis patients and healthy controls using new indices of the right and left heart systems. RESULT: Indices of the right and left heart systems in dialysis patients were significantly higher than those in healthy controls. With respect to hypotension during dialysis, patients were divided into two groups, a group with decreased blood pressure (group A: 27 patients) and a group with normal blood pressure (group B: 13 patients). Only the left heart system index in group A was significantly higher. There were no significant differences in other M-mode Doppler indices between the two groups. CONCLUSION: The new index was a more sensitive evaluator of cardiac function and predictor of hypotension during dialysis compared to standard echocardiographic indices.

Liddle's syndrome in an elderly woman.

A 78-year-old woman with hypertension was hospitalized with acute bronchitis. However, she was also found to have hypernatremia, hypokalemia, and metabolic alkalosis. Detailed examination showed a low plasma renin activity and plasma aldosterone concentration. A provisional diagnosis of Liddle's syndrome was established and the patient was successfully treated with triamterene. Although Liddle's syndrome is generally considered an inherited hypertensive disease found in young people, a review of the literature indicated that muscle weakness is an important clinical finding in elderly patients with this disease. Liddle's syndrome should be considered in the differential diagnosis of hypertension even in elderly individuals.

Novel biosensor for the rapid measurement of estrogen based on a ligand-receptor interaction.

A bioaffinity sensor was developed aiming at the detection of estrogen. This biosensor system is based on the specific binding of estrogen to its receptor immobilized on a gold disk electrode. The recombinant DNA encoding human estrogen receptor ligand-binding domain was expressed in bacteria using the histidine-tag fusion system. The expression of the fusion protein was under control of a bacteriophage T7 promoter, and the protein was purified under native conditions by affinity chromatography, which is based on a specific interaction between a histidine-tag, located in the N-terminus of the protein, and the Ni(II) chelate adsorbent. The protein was immobilized on an Au-electrode with Ni(II)-mediated chemisorption using a histidine tag and thiol-modified iminodiacetic acid. Cyclic voltammetric measurements showed that the reversible electrochemical reaction of a ferrocyanide/ferricyanide redox couple was suppressed by the presence of estrogen in a concentration-dependent manner. It seems reasonable to suppose that the electrostatic property of the protein layer on the electrode surface was altered by complexation with estrogen. These data suggest that this biosensor is applicable to the evaluation binding activities of the chemicals toward the human estrogen receptor.

Right ventricular impairment in patients with chronic respiratory failure on home oxygen therapy--non-invasive assessment using a new Doppler index.

We evaluated the usefulness of the newly defined Doppler index combining systolic and diastolic myocardial performance, in assessing right-heart dysfunction in 29 patients with chronic respiratory failure caused by old tuberculosis who were on 24-h home oxygen therapy. We measured tricuspid inflow velocity, right-ventricular outflow velocity, late/early diastolic peak velocities (A/E), the ratio between pre-ejection period and ejection time (PEP/ET), and the new index of systolic and diastolic myocardial performance (SDMP) calculated as (isovolumetric contraction time + isovolumetric relaxation time)/ejection time. The calculated A/E, PEP/ET and SDMP in our patients were significantly higher than those in age-matched healthy subjects (n = 37, mean age 67 +/- 8 years). There was no overlap in the SDMP index between healthy subjects and patients and the index was not influenced by heart rate. Our results suggest that SDMP index is a better marker than A/E and PEP/ET for the assessment of right-ventricular impairment.

Left ventricular mass and global function in essential hypertension after antihypertensive therapy.

This study compares left ventricular global function in 55 patients (25 with hypertrophy and 30 without hypertrophy) with essential hypertension, whose blood pressure had been stable for longer than 1 year, with that in 35 healthy subjects. Left ventricular global function was calculated using the echocardiographic Doppler index as described by Tei et al. (Tei index). No significant differences were observed in echocardiographic left ventricular systolic function between the three groups. Left ventricular global function differed significantly between the three groups, however, suggesting impaired left ventricular global function even in the absence of left ventricular hypertrophy. Similar changes were observed in the ratio of peak velocity of atrial systole to peak velocity of early diastole during left ventricular inflow waveform (A/E), indicating that this disorder mainly reflects impaired left ventricular diastolic function. Unlike A/E, the Tei index is not affected by increasing age, and, therefore, is appropriate for evaluating left ventricular global function in hypertensive patients, most of whom are middle-aged or older. This index may be useful for determining treatment strategy and evaluating treatment effects.

Evaluation of right-ventricular function by Doppler echocardiography in patients with chronic respiratory failure.

In patients with chronic respiratory failure, right-ventricular function was non-invasively evaluated by Doppler echocardiography. A total of 31 patients (16 men, 15 women; mean age 65.8 +/- 7.12 years) with pulmonary tuberculosis sequelae who had received home oxygen therapy during the preceding 6 or more months, were studied. Right-ventricular inflow and outflow waveforms were recorded, and right-ventricular function was evaluated using a new Doppler index combining systolic and diastolic function. On continuous wave Doppler echocardiography, estimated systolic pulmonary arterial pressure was calculated from the gradient between the right atrium and right ventricle. There was no correlation between the new Doppler index and systolic pulmonary arterial pressure, and some patients showed high index values despite low systolic pulmonary arterial pressure. The new Doppler index facilitated evaluation of ventricular function irrespective of right-ventricular afterload.

Use of [123I]-BMIPP myocardial scintigraphy for the clinical evaluation of a fatty-acid metabolism disorder of the right ventricle in chronic respiratory and pulmonary vascular disease.

The objective of this study was to evaluate whether or not right ventricle (RV) uptake of iodine-123-labelled-beta-methyliodophenylpentadecanoic acid ([123I]-BMIPP) correlated with the degree of right ventricular pressure overload (RVPO). Myocardial scintigraphy of [123I]-BMIPP and thallium-201 (201Tl) was performed on 46 patients with RVPO. We determined the right ventricle (RV)/left ventricle (LV) ratio = (radioactivities of RV)/(radioactivities of LV), and the RV metabolic index (RVMI) = (RV/LV ratio of [123I]-BMIPP)/(RV/LV ratio of 201Tl). We also evaluated the correlation between RVMI and mean pulmonary arterial pressure (mPAP), and between RVMI and total pulmonary resistance (TPR). Significant correlations were found between the RV/LV ratio of [123I]-BMIPP and mPAP and between the RV/LV ratio of [123I]-BMIPP and TPR. In addition, a significant negative correlation was observed between RVMI and mPAP and between RVMI and TPR. RVMI declined as RVPO increased, suggesting the presence of a fatty-acid metabolism disorder of the RV. Moreover, [123I]-BMIPP myocardial scintigraphy could be useful for evaluating a disorder of the fatty-acid metabolism of the RV with RVPO.

Silver and thallium(I) complexation with dibenzo-16-crown-4.

Dibenzo-16-crown-4 (1) indicates high silver and thallium(I) ion selectivity over sodium, potassium, and rubidium ion evaluated from the solvent extraction of metal picrates, while its cation-binding ability is lower than those of dibenzo-18-crown-6 (2) and dibenzo-22-crown-6 (3). Taking account of the highest thallium(I) ion selectivity for 1 obtained from extraction experiments, PVC membrane thallium(I)-selective electrodes based on 1 are prepared. The electrode shows the best potentiometric selectivity coefficients for thallium(I) over potassium and rubidium than those of 2 and 3, and commercially available bis(crown ether)s (4).