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Results for “The Right to Reproduce”

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PubMed1986

[Improved reproducibility of contrast echocardiography by SH U 454. Experimental studies using digital subtraction echocardiography].

The right heart chambers of 10 animals were contrasted by conventional (NaCl, CO2, H2O2, indocyanine green (ICG), haemaccel) and a newly developed echo-contrast medium (SH U 454) and studied by 2-D echocardiography. By means of digital subtraction echocardiography (DSE) endocardial borders were defined automatically and the results were compared with the manual input of endocardial borders of original and contrast echocardiograms. The area enclosed by these borders served as basis for the calculation of reproducibility (in %) and correlations. The following correlation coefficients (r) and SEE were calculated between the areas defined by the different contrast media and DSE and manually derived borders: r = 0.85, 3.98 cm2 (ICG), and 0.89, 1.00 cm2 (haemaccel). The best calculations were found using SH U 454 in concentrations between 100 and 300 mg/ml. The correlation coefficients were in the range of r = 0.95 and 0.98 with an SEE of 0.21 to 0.56 cm2 between manually and automatically derived contours. Comparing the reproducibility of data between the different evaluation methods we found the following results: manual input of endocardial borders in original echocardiograms 12.3%-16.9%; manual definition of endocardial borders in contrast echocardiograms 2.0% (SH U 454) - 15.7% (CO2); automatic contour finding in original echocardiograms 8.6%-28.9% (mean 21.6%); automatic definition of endocardium by DSE in contrast echocardiograms 7.6% (ICG) - 0.9% (SH U 454, 300 mg/ml). Our results demonstrate that digital subtraction echocardiography is a simple an safe procedure to define endocardial contours if echo contrast media lead to a uniform and homogeneous opacification of the left and right cardiac cavities.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1977

The renin-angiotensin-aldosterone system in rabbits with congestive heart failure produced by aortic constriction.

Severe constriction of the suprarenal abdominal aorta of 3-kg rabbits to 3.7+/-0.2 mm2 and maintenance of a daily sodium intake of 10 mE q by infusion of 0.9% sodium chloride resulted in a progressive increase in central ear arterial pressure to 106+/-3 (SEM) mm Hg (control=79+/-1). This was accompanied by a progressive increase in left ventricular end-diastolic pressure to 22+/-2 mm Hg (control=3+/-1), plasma renin activity to 21+/-5 ng of angiotensin/hour per ml (control=5+/-1), plasma aldosterone concentration to 99+/-23 pg/ml (control=14+/-4), and plasma sodium concentration to 142+/-1 mEq/liter (control=136+/-1). Urinary excretion of sodium decreased to 3.9+/-0.7 mEq/day and marked fluid retention occurred. We also found that these changes were accompanied by a decrease in hematocrit to 24+/-2% (control=40+/-1), formation of 36+/-9 ml of fluid in the thoracic cavity, 33+/-9 ml of ascites, pulmonary congestion and edema, hepatic congestion, and enlargement and hypertrophy of both the left and right ventricles. All rabbits died of ventricular failure at a time that was partly related to the degree of aortic constriction and that ranged from 2 to 12 days. The model we have established is chronic, highly reproducible, easy to produce, and inexpensive, and resembles the clinical syndrome of right and left congestive heart failure in man. Furthermore, the studies provide evidence for an important role of the renin-angiotensin-aldosterone system in the fluid retention that leads to pulmonary and systemic venous congestion after suprarenal aortic constriction.

Aldosterone↗

PubMedDate not supplied

Three-dimensional echocardiographic reconstruction of right ventricular volume: in vitro comparison with two-dimensional methods.

Two-dimensional echocardiographic measures of right ventricular volume are limited by the asymmetric and crescentic shape of that ventricle and the difficulty in obtaining standardized views. We have developed a three-dimensional echocardiographic system that automatically integrates images and positional data and calculates right ventricular volume without the need for geometric assumptions or standardized views and a surfacing algorithm that takes advantage of the full three-dimensional data set. The accuracy of this system was studied and compared with two-dimensional methods in 12 gel-filled excised human right ventricles (18 to 74 ml). Volumes calculated by three-dimensional echocardiography correlated well with actual values (r = 0.99) and agreed more closely with them than did those obtained by two-dimensional methods (p < 0.02).

Algorithms↗

PubMed1995

Reproducibility of topographic measurements of the macula with a scanning laser ophthalmoscope.

BACKGROUND: The Heidelberg retina tomograph, a scanning laser ophthalmoscope that uses confocal optics to provide high resolution of images, is able to scan the retina in three dimensions to obtain quantitative topographic measurements. The authors evaluated its usefulness for measuring macular lesions by determining the reproducibility of its topographic measurements at the macula. METHODS: For each of ten healthy patients, the authors took five images with the patient's right eye undilated and five with the eye cyclopleged and dilated. As a measure of reproducibility, the standard deviation of height measurements for the same location at the macula was calculated for each patient and then the pooled standard deviation for all patients was calculated. The authors performed similar calculations for the mean depth within a contour line. RESULTS: The pooled standard deviation for height measurements was 47.4 microns in undilated eyes and 36.0 microns in cyclopleged, dilated eyes. The authors obtained an extremely low standard deviation of 2.2 microns when the software calculated relative differences between measurements, such as the mean depth within a contour line. When the average of three height measurement values on 1 day was compared with the average of the three values on another day, the 95% confidence interval was +/- 58.7 microns for mean height values and +/- 3.7 microns for mean depth values within a contour line. CONCLUSIONS: The authors obtained good reproducibility for height measurements with the Heidelberg retina tomograph and excellent reproducibility when the instrument calculated relative differences in height measurements. The authors recommend that patients, especially young patients, be dilated and cyclopleged to obtain lower variability of measurements. The scanning laser ophthalmoscope could potentially be used to quantify small changes in retinal lesions.

Adult↗

PubMed1989

Antiarrhythmic effects of desethylamiodarone in dogs with subacute myocardial infarction and inducible ventricular arrhythmias.

To determine if desethylamiodarone (DA), the principal metabolite of amiodarone, has antiarrhythmic activity, DA was administered intravenously (i.v.) as a 5 mg/kg bolus followed by a 2-h infusion of 8 mg/kg/h to 12 dogs with 5-7-day-old myocardial infarction and reproducibly inducible sustained ventricular arrhythmias. Programmed electrical stimulation of the right ventricle was repeated, and plasma DA concentration was determined at 15-min intervals during DA administration. At the end of the infusion, the animals were killed and DA concentration in infarcted and noninfarcted myocardium was measured. Grading and statistical analysis of induced arrhythmias revealed significant amelioration during DA infusion, with partial or complete suppression in 9 of the 12 dogs. Apparent steady-state plasma DA concentration (range 0.8-1.0 micrograms/ml) was achieved and maintained during the final 105 min of infusion. DA concentration in noninfarcted myocardium (62.6 +/- 22.0 micrograms/g) was significantly higher (p less than 0.01) than DA concentration in infarcted myocardium (25.6 +/- 18.6 micrograms/g). We conclude that DA administered i.v. has antiarrhythmic activity in dogs with subacute myocardial infarction and reproducibly inducible sustained ventricular arrhythmias.

Amiodarone↗

PubMed1991

Right and left ventricular stroke volume measurements with velocity-encoded cine MR imaging: in vitro and in vivo validation.

The accuracy of measurements of flow velocity determined by using cine MR phase velocity mapping--velocity-encoded cine (VEC) MR--was assessed by comparing VEC MR data with independent measurements in a flow phantom and in human subjects. Constant flow velocities generated in a phantom (range, 20-408 cm/sec) were determined correctly by VEC MR (r = .997, standard error of the estimate [SEE] = 7.9 cm/sec). Peak systolic velocities in the main pulmonary artery determined by VEC MR correlated well with the measurements obtained by using continuous-wave Doppler echocardiography (r = .91). Stroke volumes measured at the aorta by VEC MR and continuous-wave Doppler imaging also correlated well with each other (r = .80). VEC MR measurements of aortic and pulmonary flow provided left and right ventricular stroke volumes that correlated well with left ventricular stroke volumes determined by short-axis cine MR images (r = .98, SEE = 3.7 ml, and r = .95, SEE = 4.8 ml, respectively). Intra- and interobserver variabilities were small for both left and right ventricular stroke volumes as measured with VEC MR. These results indicate that VEC MR accurately and reproducibly measures aortic and pulmonary flow velocities and volumes in the physiologic range of humans, and can be used to measure right and left ventricular stroke volumes under normal flow conditions.

Adult↗

PubMed2006

Periodontal assessment by right- and left-handed examiners: is there a difference?

BACKGROUND: Multiple factors that influence the precision of periodontal probing measurements have been identified. These factors can be categorized as being dependent upon host-related, probe-related, or examiner-related variables. However, the potential influence of examiner handedness (right or left) on the measurement of periodontal probing depths (PDs) has not been addressed. The purpose of this study was to determine whether the measurements of PDs in the right and left quadrants are influenced by the handedness of the examiner. METHODS: Eight systemically healthy adult subjects with varying degrees of attachment loss and a minimum of 20 teeth were examined by five right-handed and five left-handed clinicians. The 10 clinicians were trained and calibrated for reproducible probe placement and angulation. PDs were measured using a conventional periodontal probe at six sites per tooth. Mean PD measurements were compared between right- and left-handed examiners using analysis of variance (ANOVA) with a random patient effect to correlate participant data and a random effect for the examiner. RESULTS: There was no statistical difference in the measurement of PDs between right- and left-handed examiners at various locations in the mouth (P>0.17 in all cases). Only three individual sites showed a statistically significantly different mean PD between right- and left-handed examiners (unadjusted P<0.05; differences at or near 0.5 mm). Overall, right-handed examiners tended to record slightly higher PD measurements than left-handed examiners, but this difference did not reach statistical significance. CONCLUSIONS: The handedness of the periodontal examiner does not appear to influence the recorded measurement of probing depths. This finding is relevant to those conducting clinical research involving assessment of periodontal status.

Adult↗

PubMed1988

Surgical treatment of right atrial focal tachycardia in adults.

Although successful operative treatment of atrial focal tachycardia has been reported in children, there are only isolated reports of surgical treatment of this arrhythmia in adults. In this case series of eight patients (aged 10 to 53 years) with drug-resistant right atrial focal tachycardia, results of electrophysiologic studies, surgical techniques and long-term follow-up are described. Atrial focal tachycardia was reproduced during electrophysiologic study, and endocardial mapping localized the earliest onset of atrial activation in the right atrium in all patients. Epicardial mapping confirmed the location of atrial tachycardia foci in seven of eight patients whose tachycardia was inducible intraoperatively. Of four patients treated with epicardial cryoablation alone, two had recurrent tachycardia and required a second procedure. None have had arrhythmia recurrence. In all four patients after right atrial excision (two of whom had intraoperative recurrence of atrial focal tachycardia after epicardial cryoablation alone), there has been no recurrence during a clinical follow-up period of 11 to 67 months (mean 30). It is concluded that in adult patients 1) electrophysiologic study with endocardial and epicardial mapping permits successful surgical treatment of atrial focal tachycardia; 2) epicardial cryoablation alone may be associated with recurrence of atrial focal tachycardia either intraoperatively or postoperatively; and 3) subtotal right atrial resection appears to be a well tolerated procedure with no long-term recurrence of atrial focal tachycardia.

Adult↗

PubMed2000

[Intravascular Doppler for the evaluation of renal blood flow: validation and demonstration of vessel reactivity].

AIM: To assess the feasibility and to demonstrate the potential clinical application of intravascular doppler in the evaluation of renal blood flow in patients with hypertension and normal renal arteries. MATERIALS AND METHODS: Intravascular doppler was used to measure renal blood flow in 19 patients (34 kidneys) during arteriography to rule out renovascular hypertension. Arteriography showed no evidence of renal artery stenosis in any patient. Hemodynamic parameters, renal artery diameter, and doppler measurements were undertaken at baseline, after injection of a bolus (10 ml) of normal (0.9%) saline, and after injection of isosorbide dinitrate (1 mg diluted in 10 ml normal saline). RESULTS: Repeated measurements of renal blood flow confirmed the reproducibility of the technique. Basal blood flow was similar in both right and left kidneys; injection of vehicle solution (10 ml normal saline) had no effect on doppler parameters. Injection of isosorbide dinitrate resulted in a significant increase in renal blood flow velocity reflecting an increase in renal blood flow; this demonstrates the existence of a renal flow reserve. The degree of increase in renal blood flow varied significantly between kidneys. CONCLUSIONS: Intravascular doppler is a safe, effective, and reproducible technique for measurement of renal blood flow. It allows evaluation of variations in renal blood flow in response to diverse vasoactive drugs or other vasomotor stimuli. The present study demonstrated the heterogenous response of renal blood flow in response to vasodilator stimuli.

Angiography↗

PubMed1999

Preload assessment in patients with an open abdomen.

BACKGROUND: Intra-abdominal hypertension and abdominal compartment syndrome cause significant morbidity and mortality in surgical and trauma patients. Maintenance of intravascular preload and use of open abdomen techniques are essential. The accuracy of pulmonary artery occlusion pressure (PAOP) and central venous pressure (CVP) in patients with intra-abdominal hypertension has been questioned. METHODS: Twenty surgical and trauma patients with intra-abdominal hypertension requiring open abdominal decompression were monitored using volumetric thermodilution pulmonary artery catheters. Hemodynamic, oxygenation, inspiratory, and intravesicular pressure measurements were collected prospectively. PAOP, CVP, and right ventricular end-diastolic volume index (RVEDVI) were compared as estimates of preload status. RESULTS: Multiple regression analysis demonstrated that cardiac index correlated significantly better with RVEDVI (r = 0.69) than with PAOP (r = -0.27) or CVP (r = -0.28) during resuscitation after open abdominal decompression (p < 0.0001). CONCLUSION: RVEDVI is superior to PAOP and CVP as an estimate of preload status in patients with an open abdomen.

Adolescent↗

PubMed2004

Quantitative assessment of right ventricular systolic function by the analysis of right ventricular contrast time-intensity curve.

To study reliability and reliable indices of quantitative assessment of right ventricular systolic function by time-intensity curve (TIC) with right ventricular contrast, 5% sonicated human albumin was injected intravenously at a does of 0.08 ml/kg into 10 dogs at baseline status and cardiac insufficiency. Apical four-chamber view was observed for washin and washout of contrast agent from right ventricle. The parameters of TIC were obtained by curve fitting. The differences of parameters were analyzed in different states of cardiac functions. Among the parameters derived from TIC, the time constant (k) was decreased significantly with decline of cardiac function (P<0.001). But half-time of decent of peak intensity (HT) and mean-transit-time (MTT) of washout were increased significantly (P<0.001). The k was strongly related to cardiac output of right ventricle (CO) and ejection fraction (EF) of left ventricle and fractional shortening (FS) of left ventricle. Right ventricular systolic function could be assessed reliably by the parameters derived from TIC with right ventricular contrast echocardiography. The k, HT and MTT are reliable indices for quantitative assessment of right ventricular systolic function.

Animals↗

PubMed2006

Accuracy, reproducibility, and comparability of Doppler tissue imaging by two high-end ultrasound systems.

INTRODUCTION: Doppler tissue imaging is a new technology for quantitative evaluation of myocardial motion and contractility, and is available in several ultrasound systems. This study evaluates the comparability, accuracy, and reproducibility of measurements of velocity, strain rate, and strain by two high-end ultrasound systems. METHODS: Accuracy was assessed by imaging a tissue-mimicking gelatin phantom, and the comparability of measurements in the right ventricular free wall and interventricular septum was assessed in 20 healthy participants. Reproducibility was evaluated by repeated recordings in vitro and in a random subset of patients. RESULTS: In vitro, a high degree of accuracy was found in both systems, with one system measuring slightly lower values than the reference values (mean difference 0.35 +/- 0.18 cm/s, P < .001). Values higher than the reference values were measured by both systems for strain and strain rate. In vivo, no systematic differences in measured velocities, strain rate, and strain were found; however, wide limits of agreement were seen for strain and strain rate. Measurements of tissue velocity, strain, and strain rate were well reproducible, nevertheless wide variation was found in both systems (coefficient of variation = 9%-19%). CONCLUSION: For clinical purposes, both systems have sufficient accuracy for measurements of tissue velocity. The variation in measurements of strain rate and strain by Doppler tissue imaging should be taken into account when designing studies using this new technology. Approaches to potentially reduce this variation should be addressed in future studies.

Echocardiography, Doppler↗

PubMed2004

[A new method of pulmonary artery cannulation with minimally invasive decannulation for right ventricular assistance:an animal experiment].

OBJECTIVE: To create a new method of pulmonary artery cannulation during operation for right ventricular assistance, for which minimally invasive decannulation can be done after operation. METHODS: A specially-made disassemblable composite graft consisting of a woven dacron tube and a bovine pericardial tube (composite graft) was anastomosed to the pulmonary artery as a pathway in seven dogs by median sternotomy. The end of the woven dacron tube and a link-thread for connecting the two tubes in the composite graft were drawn outside the body through an intercostal tunnel. A predisposed drawing-tieing thread in the composite graft was drawn outside through another intercostal tunnel and then tightened. An inflow cannula was placed into the left femoral vein or jugular vein via an incision of skin so as to establish a right ventricular assist system. By means of the centrifugal pump, the right ventricular bypass was established. After stopping the pumping, the 2 sets of predisposed prolene thread in the composite graft were tied by catheter and knotting tool via the small skin incision, 8 knots for each set, to close the bovine pericardial tube, and then the drawing-tieing thread, link-thread, and the dacron tube in the composite graft were removed. Median sternotomy was performed again to observe the anastomotic stoma, the closure of the stump of bovine pericardial tube, and whether hemorrhage occurred. RESULTS: The mean maximum output of right ventricular assist system from left femoral or jugular vein to pulmonary artery was (64.4 +/- 12.3) ml.min(-1).kg(-1). The second sternotomy showed satisfactory knotting on the bovine pericardial tube except in one case, whose second set of drawing-tieing thread was tied in the seventh knot and failed to be drawn out, thus partially remained in the body. No bleeding was found in all cases. CONCLUSION: The new cannulating methods with minimally invasive decannulation after operation created in this study is simple, easy and effective.

Animals↗

PubMed2001

The influence of task characteristics on the intermanual asymmetry of motor overflow.

The two studies reported here were designed to test the proposition that greater motor overflow occurs when movements are performed by the non-dominant hand. Unlike previous studies using normal adults, the task in these studies did not require force production. In the first study, a group of 19 right-handed participants performed unweighted finger lifting. That the frequency of motor overflow occurrence was the same regardless of which hand performed the task, did not support findings from other studies where tasks involving force production resulted in more overflow when performed by the non-dominant hand. To investigate further the influence of task characteristics on motor overflow occurrence, in the second study participants were required to remember and reproduce a prescribed sequence of four finger lifts. Left- and right-handed participants (N = 30) performed both single and sequenced finger lifting. The relative frequency of motor overflow (unintended lifts of fingers of the passive hand) was compared between hand preference groups, active hand and task type (single/sequenced). Contrary to the expectation that motor overflow would be greater for the sequenced finger lifting task, overflow was exhibited with a significantly greater frequency on single finger lifting. This finding indicates that task characteristics influence the pattern of overflow occurrence in normal adults. The task used in this study did not involve force production and did not result in an intermanual asymmetry of motor overflow. This contrasts with findings from other studies requiring adults to exert forces where greater overflow occurred when the non-dominant hand was active. However, this study confirms previous findings which show that left-handers produce greater overflow compared to right-handers regardless of the task being performed and the hand performing the task.

Adolescent↗

PubMed1990

Estimation of right ventricular pressure by 201Tl scintigraphy in paediatric cardiac disease.

To estimate right ventricular overload in paediatric cardiac disease, 201Tl scintigraphy was used to quantify right ventricular uptake. Six methods for calculating the 201Tl right-to-left ventricular uptake ratio (TRL) were compared, based on the location of regions of interest (ROIs), use of total count or mean count density, and the ROI-based method or profile method. When the TRL was compared with the right-to-left ventricular peak systolic pressure ratio (RVP/LVP), the mean count density method using entire right and left ventricular ROIs seemed to be appropriate, considering its simplicity, reproducibility and regression line. The linear regression line was RVP/LVP = 1.15 x TRL - 0.13 (n = 15, P = -0.0001), and RVP(mm Hg) = 162 x TRL - 33 (n = 15, P = 0.0001). In four patients with pulmonary stenosis, the changes of TRL were in good agreement with the right ventricular pressure changes after percutaneous balloon valvuloplasty. Thus, evaluation of thallium scintigraphy using this quantitative method can be a simple and effective way to evaluate patients with right ventricular pressure overloading.

Adolescent↗

PubMed1997

Reproducibility of vitreous fluorophotometry in patients with type 1 diabetes mellitus.

We assessed the day-to-day reproducible of vitreous fluorophotometry in 7 type 1 diabetic patients and in 1 healthy control subject. The coefficient of variation for duplicate measurements was 33.7, 40.3 and 23.6%, for the right eyes, the left eyes and mean values of both eyes, respectively. Assessment of reproducibility in 1 healthy subject, measured 4 times, resulted in coefficients of variation of about 60%. These values are somewhat worse than those obtained by others in healthy subjects. Since technical problems do not seem to play a significant role in this regard, our reproducibility results reflect the true biological variability of the permeability of the blood-retina barrier assessed by vitreous fluorophotometry in diabetic patients. This variability is substantial. Therefore, we conclude that this method is not precise enough to be used in intervention studies with a limited number of subjects.

Adult↗

PubMed1996

Fundamentals of transorbital sonographic evaluation of optic nerve sheath expansion under intracranial hypertension. I. Experimental study.

The optic nerve, ontogenetically part of the central nervous system, is surrounded by subarachnoidal cerebrospinal fluid (CSF) and dura mater. Because of the connection with the intracranial subarachnoidal space, CSF pressure variations influence the optic nerve sheath (ONS) diameter. Histologic studies revealed a segment of the optic nerve in which maximal diameter fluctuations could be expected, namely the bulging dura mater region approximately 3 mm behind the papilla. Twenty preparations of optic nerves obtained post mortem were examined sonographically before and after dilatation of the ONS, by means of measurement from three different projections. After gelatine-induced widening of the subarachnoidal space, the mean diameter increased by 60% at 3 mm behind the optic nerve head, but only by 35% at 10 mm distance. Independent measurements by two examiners correlated highly, which indicates excellent reproducibility of the sonographic measurements. The optimal experimental scanning position was at a right angle to the optic nerve (longitudinal section). Under clinical conditions, however, only axial sections can be obtained using anterior probe positions with transbulbar sound directions. Using such axial projections the 3 mm position proved reliably reproducible. The reduced resolution of the optic nerve itself, allowing it to be distinguished from its surrounding sheath, proved to be somewhat disadvantageous from this projection angle.

Adult↗

PubMed1998

Right ventricular regional function using MR tagging: normals versus chronic pulmonary hypertension.

Right ventricular (RV) regional function, in both normal and diseased states, is not well characterized. Using 1D MR myocardial tagging, RV and septal intramyocardial segmental shortening was noninvasively measured in ten healthy subjects and in seven patients with chronic pulmonary hypertension. The normal RV free wall regional shortening was not uniform. A pattern of increasing RV free wall short-axis shortening was found from the RV outflow tract to the RV apex, and a more complex pattern of RV free wall long-axis shortening was observed. Both regional short- and long-axis shortening were globally reduced in pulmonary hypertension patients, with the greatest decreases in the RV outflow tract and in the basal septal wall region. Regional RV function can be quantitatively evaluated using MR tagging to determine the impact of chronic pulmonary hypertension on RV performance.

Adolescent↗