| 1. |
- Lasaitiene, Daina, 1970, et al.
(författare)
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Neonatal ACE inhibition in rats interferes with lung development
- 2004
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Ingår i: Clin Physiol Funct Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 24:1, s. 65-8
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Tidskriftsartikel (refereegranskat)abstract
- The renin-angiotensin system (RAS) is developmentally up-regulated and it is essential for kidney development in several species. Given the fact that the rat lung undergoes postnatal development, the mammalian lung possesses the highest angiotensin-converting enzyme (ACE) levels and ACE activity increases during the first weeks postpartum, we tested the hypothesis that ACE inhibition influences postnatal lung development. Rats were given the ACE inhibitor enalapril (10 mg kg(-1)) from 0 to 9 days of age and their lungs were examined at day 4 and 9. Lung structure was evaluated by means of light microscopy, and surface tension of bronchoalveolar lavage fluid was measured by means of a Wilhelmy balance. Neonatal ACE inhibition lowered the surface tension of bronchoalveolar lavage fluid and caused widening of respiratory airspaces and thinning of alveolar septa. Our results suggest that early postnatal ACE inhibition in rats interferes with lung development.
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| 2. |
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| 3. |
- Wisén, Anita, et al.
(författare)
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A refined technique for determining the respiratory gas exchange responses to anaerobic metabolism during progressive exercise - repeatability in a group of healthy men.
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 24:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- The respiratory gas exchange and ventilation during an incremental cycle exercise test were analysed in a group of 19 healthy, moderately fit men. Different computer algorithms were used to estimate the VO2 values where: (i) the rate of VCO2 increase just exceeds the rate of VO2 increase (DX, derivative crossing), (ii) VCO2/VO2 = 1·00 (PX, point of crossing) and (iii) ventilation (VE) increases disproportionately in relation to VCO2 (PQ, point of VCO2 equivalent rise). The DX and PQ measurements were analysed using a new approach employing polynomial regression and the value of PX was determined following low-pass filtration of raw data. The repeatability of the measurements was evaluated with a 5-6 week interval between the tests. The correlations between tests were 0·75 at DX, 0·85 at PX and 0·62 at PQ. The mean differences between the repeated tests were not statistically significant. The repeatability of VO2, in absolute values expressed as ±2 SD of the differences between the tests, had values of 5·0, 6·1 and 9·5 ml min-1 kg-1 for DX, PX and PQ, respectively. The mean value of VO2 for each measurement point expressed as a percentage of VO2max was 54% at DX, 68% at PX and 70% at PQ. The most common sequence of the measured values was DX < PX < PQ, but the sequence DX < PQ < PX was also observed. It is concluded that the gas exchange responses to developing anaerobic metabolism during progressive exercise can be characterized by a series of thresholds. However, the considerable variation in absolute values in the two testing occasions requires further attention.
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| 4. |
- Blomstrand, Peter, et al.
(författare)
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Pulsed tissue Doppler imaging for the detection of myocardial ischaemia, a comparison with myocardial perfusion SPECT
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - : John Wiley & Sons. - 1475-0961 .- 1475-097X. ; 24:5, s. 289-295
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Tidskriftsartikel (refereegranskat)abstract
- In order to compare the diagnostic ability of pulsed tissue Doppler and myocardial perfusion Single Photon Emission Computed Tomography (SPECT) in patients with a history of unstable coronary artery disease, CAD, 26 patients, 22 men and four women, age 47-76 years, were investigated in a prospective study, 5-10 day after an episode of unstable angina. Tissue Doppler and two-dimensional echocardiography were performed during dobutamine stress testing and myocardial scintigraphy after bicycle exercise and at rest. Patients with a normal SPECT had higher peak systolic velocity during dobutamine infusion, 18.9 ± 4.1 cm s-1, than patients with ischaemia, 12.2 ± 3.8 cm s-1 (P<0.001) or scar, 8.8 ± 3.0 cm s-1 (P<0.01). In a territorial analysis the difference in peak systolic velocity between areas with a normal and abnormal SPECT was less apparent. Failure to achieve ≥13 cm s-1 in mean-peak systolic velocity was the most accurate criterion for detection of significant CAD on SPECT. We conclude that pulsed tissue Doppler can be used for objective quantification of left ventricular wall motion during dobutamine stress testing and for identification of patients with CAD on SPECT but not for identification of regional ischaemia.
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| 5. |
- Brodin, Lars-Åke
(författare)
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Tissue Doppler, a fundamental tool for parametric imaging
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 24:3, s. 147-155
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Tidskriftsartikel (refereegranskat)abstract
- Tissue Doppler has been used for clinical applications since 1989. It has been developed from a pulsed Doppler acquisition tool towards a method where extraction of velocities can be performed from colour-coded images. This has introduced a further development into different forms of parametric images describing different myocardial functions as colour-coded information, like deformation imaging, motion imaging and phase imaging. The technical requirements have been established with temporal requirements of frame rates in acquisition exceeding 100 frames s(-1). The most powerful application of the tissue Doppler technique today is perhaps to quantify the myocardial functional reserve, during stress echocardiography, making the method applicable to diagnose the presence of coronary disease with an accuracy exceeding that of nuclear and other non-invasive techniques. The method has also great potential for future developments with introduction of more regional measuring variables.
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| 6. |
- Carlhäll, Carljohan, 1973-, et al.
(författare)
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A novel method to assess systolic ventricular function using atrioventricular plane displacement : a study in young healthy males and patients with heart disease
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 24:4, s. 190-195
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of atrioventricular plane displacement (AVPD) is a well established method for assessment of both systolic and diastolic ventricular function. For several years, AVPD has been a clinical tool and there are many current, as well as potential, areas of application. However, clinical work has shown that the traditional method for evaluation of systolic ventricular function, called total AVPD, does not temporally reflect true systole. Systolic AVPD is a new approach for measuring AVPD to assess ventricular systolic function. We wished to apply this new model in healthy subjects and in patients with different common heart diseases. Twenty-eight young healthy males and 30 patients (aortic stenosis, left sided regurgitant lesions, postmyocardial infarction) were enrolled. AVPD was obtained at the four standard sites by M-mode. Total AVPD was measured in the conventional way and systolic AVPD by identifying true systole, by means of mitral- and aortic valve closure respectively. Ventricular volumes were calculated according to biplane Simpson's rule. The systolic AVPD measurements were significantly lower than the total measurements, at both atrioventricular planes in all groups (P<0·001). This discrepancy was greater at the mitral than at the tricuspid annulus in the patients 24·2% vs. 15·5% (P<0·001), but did not differ in the healthy subjects. At the mitral annulus, this discrepancy also seemed to be more pronounced in the patients than in the healthy subjects 24·2% vs. 10·7%. When assessing ventricular systolic function by AVPD, the conventional method overestimates the amplitude in relation to true systolic function in both patients with heart disease and in young healthy males. Thus, there are uncertainties regarding earlier estimations of AVPD in terms of expression of systolic function and regarding previously presented reference values. We recommend the proposed methodology.
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| 7. |
- Ekelund, Ulf, et al.
(författare)
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The validity of the Computer Science and Applications activity monitor for use in coronary artery disease patients during level walking
- 2002
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 22:4, s. 248-253
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Tidskriftsartikel (refereegranskat)abstract
- The principal aim of the present study was to examine the validity of the Computer Science and Applications (CSA) activity monitor during level walking in coronary artery disease (CAD) patients. As a secondary aim, we evaluated the usefulness of two previously published energy expenditure (EE) prediction equations. Thirty-four subjects (29 men and five women), all with diagnosed CAD, volunteered to participate. Oxygen uptake (VO2) was measured by indirect calorimetry during walking on a motorized treadmill at three different speeds (3·2, 4·8 and 6·4 km h−1). Physical activity was measured simultaneously using the CSA activity monitor, secured directly to the skin on the lower back (i.e. lumbar vertebrae 4–5) with an elastic belt. The mean (±SD) activity counts were 1208 ± 429, 3258 ± 753 and 5351 ± 876 counts min−1, at the three speeds, respectively (P<0·001). Activity counts were significantly correlated to speed (r=0·92; P<0·001), VO2 (ml kg−1 min−1; r=0·87; P<0·001) and EE (kcal min−1; r=0·85, P<0·001). A stepwise linear regression analysis showed that activity counts and body weight together explained 75% of the variation in EE. Predicted EE from previously published equations differed significantly when used in this group of CAD patients. In conclusion, the CSA activity monitor is a valid instrument for assessing the intensity of physical activity during treadmill walking in CAD patients. Energy expenditure can be predicted from body weight and activity counts.
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| 8. |
- Emilsson, Kent, 1963-
(författare)
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Right ventricular long-axis function in relation to left ventricular systolic function
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 24:4, s. 212-215
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Tidskriftsartikel (refereegranskat)abstract
- A decrease in left ventricular (LV) systolic function is accompanied by a decrease in maximal relaxation velocity in LV long-axis direction, but is it also accompanied by a decrease in right ventricular (RV) long-axis function? To study this 35 consecutive patients were examined by echocardiography. Ejection fraction (LVEF) and mitral annulus motion (MAM) were used as indices of LV systolic function and tricuspid annulus motion (TAM), that is the systolic shortening in RV long-axis direction, was used as an index of RV systolic long-axis function. In the same way the maximal relaxation velocity in LV long-axis direction, that is the maximal diastolic velocity of MAM (MDV MAM), has been suggested as an index of LV diastolic function the maximal diastolic velocity of TAM (MDV TAM) can be supposed to be an index of RV diastolic function measuring the maximal relaxation velocity in the RV long-axis direction. A significant positive correlation was found between MDV TAM and MAM (r = 0.64, P<0001) and LVEF (r = 0.54, P = 0.001) and between TAM and the two studied indices of LV systolic function, with the highest correlation to MAM (r = 0.68, P<0.001) and the lowest to LVEF (r = 0.57, P<0.001). Thus, a decrease in LV systolic function is accompanied by a decrease in both systolic and diastolic RV long-axis function, findings that probably are due to the close anatomical connection between the ventricles and to changes that occur in afterload of the RV secondary to LV systolic dysfunction.
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| 9. |
- Jogestrand, T., et al.
(författare)
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Relation between the elastic properties and intima-media thickness of the common carotid artery
- 2003
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 23:3, s. 134-137
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to describe the relation between wall elasticity and intima-media thickness in the human carotid artery prior to the development of atherosclerotic plaques. Fifty-eight apparently healthy men, aged 42-65 years (mean 55 years), without symptoms of cardiovascular disease were studied. Thickness and elastic properties of the common carotid artery wall were assessed using ultrasonography and non-invasive arterial pressure measurements. The relation between the calculated intima-media area and the pressure strain elastic modulus was positive and statistically significant on the right but not on the left side. No statistically significant relations were found between the calculated intima-media area and the stiffness or between the intima-media thickness and the elastic modulus or stiffness on either side. Thus, the relations between the common carotid artery intima-media thickness/calculated intima-media area and the common carotid artery elastic modulus/stiffness are weak. In regions without atherosclerotic plaques, the elastic properties of the human carotid artery wall do not seem to be influenced by the wall thickness in an important way.
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| 10. |
- Jönsson, Björn, 1951-, et al.
(författare)
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Is oscillometric ankle pressure reliable in leg vascular disease?
- 2001
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 21:2, s. 155-163
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the study was to evaluate the validity of oscillometric systolic ankle pressure in symptomatic leg arterial occlusive disease. Ankle pressure measurements using oscillometric curves obtained using a standard 12-cm cuff with a specially designed device for signal processing were validated against the continuous wave (CW) Doppler technique. Thirty-four subjects without signs or symptoms of peripheral vascular disease (68 legs) and 47 patients with leg ischaemia (85 legs) varying from moderate claudication to critical ischaemia were examined. The oscillometric curves were analysed using several algorithms reported in the literature, based on the assumption that maximum oscillations are recorded near mean arterial pressure. In normals, reasonable agreement between CW Doppler and oscillometric methods was seen. When an algorithm that determined the lowest cuff pressure at which maximum oscillations occurred, and a characteristic ratio for systolic pressure of 0·52 was used, the mean difference between CW Doppler and oscillometry was 1·7 mmHg [range −19 to +27, limits of agreement (2 SD) 21·1 mmHg]. In ischaemic legs, oscillometry overestimated systolic ankle pressure by a mean of 28·8 mmHg [range –126 to +65, limits of agreement 82·8 mmHg]. The difference was more pronounced among patients with critical ischaemia compared with claudicants, and also more evident among diabetics. The error of oscillometric pressure determination in subjects with leg arterial disease inversely increased with CW Doppler ankle pressure. In 39% of the recordings in legs with a CW Doppler systolic pressure below 100 mmHg, the oscillometric mean arterial pressure was higher than the recorded CW Doppler systolic pressure. In conclusion, the oscillometric method to determine systolic ankle pressure, based on the concept of maximum cuff oscillations occurring near mean arterial pressure, is not reliable in leg arterial disease, usually overestimating ankle pressure.
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