| 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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| 11. |
- Naidu Sjöswärd, Kerstin, 1938-, et al.
(författare)
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Preserved bronchial dilatation after salbutamol does not guarantee protection against bronchial hyperresponsiveness
- 2003
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 23:1, s. 14-20
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Tidskriftsartikel (refereegranskat)abstract
- Racemic salbutamol, a β2-adrenoceptor agonist used for dilatation of airways, has recently been shown to induce lessened relaxation of bronchial smooth muscle and partial loss of bronchoprotection, seen as increased hyperresponsiveness, after regular treatment. The racemate undergoes stereo-selective disposition, giving higher plasma levels of S-salbutamol than that of bronchodilating R-salbutamol, thus raising S : R ratios after repeated administration. Our aim was to evaluate whether increased bronchial hyperresponsiveness (BHR) could be found even after 1 day of repeated salbutamol inhalations, with β2-receptor-induced bronchial smooth muscle relaxation remaining and whether this would be associated with plasma levels of either enantiomer. Fifteen patients with stable asthma, aged 19–54 years, were included in a randomized, cross-over study. An indirect bronchial challenge method was used [voluntary isocapnic hyperventilation of cold air (IHCA)], and airway condition tested by means of impulse oscillometry. Racemic salbutamol was inhaled three times during a 6-h period. IHCA was performed and plasma concentrations of enantiomers were measured 4 h after the last dose. Tests were also performed without preceding drug treatment. β2-Agonist-produced bronchial dilatation and protection persisted in the majority of the 15 patients 4 h after repeated inhalations of salbutamol during 1 day. In only two of the 15 patients we could trace increased BHR after salbutamol. Neither dilatation nor protection could be linked to plasma levels of either R- or S-salbutamol. The underlying mechanisms of BHR remain unknown and are dissociated from β2-receptor-mediated dilatation.
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| 12. |
- Rydén Ahlgren, Åsa, et al.
(författare)
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Female gender increases stiffness of elastic but not of muscular arteries in type I diabetic patients
- 2002
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 22:6, s. 409-415
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Tidskriftsartikel (refereegranskat)abstract
- The reason for the particularly increased risk for cardiovascular complications in diabetic women is still unclear. We have previously found decreased distensibility of elastic arteries in type I diabetic women, indicating increased cardiac load, not seen in type I diabetic men, which might be one contributing factor. Whether the effect of gender is different in muscular arteries in type I diabetic patients has not been assessed. As estimates of arterial distensibility we measured stiffness (▀) and pressure strain elastic modulus (Ep) in the muscular common femoral artery using echotracking sonography in 30 women (mean age 34 years, range 20-61) and 26 men (mean age 38 years, range 22-56) with type I diabetes. The results were compared with those of 89 healthy individuals of corresponding age and gender and with previously published results from elastic arteries in these patients obtained at the same occasion. The internal common femoral diameter was significantly decreased in both diabetic men and women. In sharp contrast to the highly significant decreased distensibility of the elastic abdominal aorta and common carotid artery in the type I diabetic women, the distensibility of the common femoral artery did not clearly differ between patients and controls, neither for women nor for men. Thus, the gender difference in changes of arterial distensibility found in elastic arteries was absent or far less obvious in the femoral artery. In conclusion, female gender seems to affect the mechanical properties of elastic, but not of large muscular arteries in type I diabetic patients. Thus, putative gender differences in arterial changes in type I diabetes are to be sought in elastic rather than muscular arteries.
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| 13. |
- Saha, S. K., et al.
(författare)
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Myocardial velocities measured during adenosine, dobutamine and supine bicycle exercise : a tissue Doppler study in healthy volunteers
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 24:5, s. 281-288
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dobutamine stress echocardiography (DSE) quantified by tissue Doppler (TVI) have improved the diagnostic capacity of the procedure. Quantification of other stress modalities, e.g. adenosine stress echo (ASE) and exercise stress echocardiography (ESE) are necessary for assessing any pathophysiological differences in different forms of stress. Methods: Ten healthy individuals underwent ASE, DSE, and ESE during a span of 2-5 days. Left ventricular (LV) apical images at rest and peak stress (max) were postprocessed using TVI on a GE System FiVe equipment. ECG-derived QRS duration (QRSD, ms), heart rate (HR, bpm), TVI-estimated basal systolic velocities (S2V, cm s(-1)), ejection time (S2T, ms) and strain (S, %) were computed off-line and compared. Longitudinal displacement imaging, tissue tracking, was also made. Results: Data for ASE, DSE and ESE during peak stress were (HR: 84 +/- 12***, 142 +/- 19, 137 +/- 27; P0.05) response at a much lower HR indicates that adenosine has minor effects on contraction presumably secondary to vasodilatation. Powerful chronotropic response to DSE and ESE is probably prerequisite for strong velocity response at the expense of strain and displacement. TVI-assisted stress echocardiography thereby shows different LV systolic response in healthy individuals, depending on stress modality.
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| 14. |
- Sparring Björkstén, Karin, et al.
(författare)
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A computerized human reference brain for rCBF/SPET technetium-99m exametazime (HMPAO) investigation of elderly
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 24:4, s. 196-204
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Tidskriftsartikel (refereegranskat)abstract
- Using the bull's eye approach, a reference brain from the single photon emission tomography (SPET) images of 10 subjects aged 62-81 years with excellent mental and physical health was constructed. SPET images were acquired twice, 1 week apart, using a single detector rotating gamma camera collecting 64 planar images over a 360° orbit. The centre of each transaxial slice was first defined with an automatic edge detecting algorithm applied to an anterior-posterior and a side profile of the brain. Each slice was divided into 40 sectors. Maximum counts/pixel in each sector was picked. The 40 maximum count values from one transaxial slice were allowed to form a horizontal row in a new parametric image on the x-axis and slice number from the vertex to the basal parts of the brain on the y-axis. This new image was scaled to a 64 × 16 pixel matrix by interpolation, which meant a normalization of all studies to the same size. The parametric image in each subject was scaled with regard to intensity by a factor calculated by a normalization procedure using the least squares analysis. Mean and SD for each pixel were calculated, thereby constructing a 'mean parametric image', and a 'SD parametric image'. These two images are meant to be used as the reference brain for evaluation of patient studies. This method can be used for objective measurements of diffuse brain changes and for pattern recognition in larger groups of patients. Statistical multifactorial analysis of parameters used for acquisition and data processing is possible. © 2004 Blackwell Publishing Ltd.
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| 15. |
- Sundblad, Patrik, et al.
(författare)
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Relationship between breath-synchronous arterial pressure and heart rate variations during orthostatic stress.
- 2003
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 23:2, s. 103-109
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Tidskriftsartikel (refereegranskat)abstract
- It has recently been shown that the phase relationship between respiration-induced changes in arterial pressure (AP) and heart rate (HR) are different in supine and upright postures. We wanted to further analyse the coupling between respiration, arterial blood pressure and HR in the time domain, and how this coupling was altered during orthostatic stress. Nine healthy subjects were studied. Respiration-induced changes in AP and HR were recorded during frequency- and volume-controlled breathing. This was done during supine rest with and without lower body negative pressure (-50 mmHg) (LBNP). All experiments were performed after beta1-blockade. Responses were averaged breath-by-breath to enhance the time resolution and to eliminate noise. The respiration-induced changes in arterial pulse pressure (PP) were different between control and LBNP: The peak in PP during the respiratory cycle occurred 0.9 +/- 0.8 (mean +/- SD) s before the onset of inspiration during supine control and 0.8 +/- 2.1 s after the onset of inspiration during LBNP (P = 0.03). These changes in the timing of peak PP significantly distorted the cyclic systolic AP and mean AP fluctuations during LBNP. Despite the altered AP response with LBNP, HR fluctuations closely correlated in time with respiration in all conditions, albeit with a significantly reduced amplitude during LBNP (-49%, P = 0.01). The results points to a lack of coupling between AP and HR during paced breathing and thus suggest that respiratory sinus dysrhythmia at least, to a large extent, is independent of the arterial baroreflex.
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| 27. |
- Evilevitch, Vladimir, et al.
(författare)
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Microvascular response in guinea pig skin to histamine challenge with and without application of skin window.
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 24:5, s. 266-269
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Tidskriftsartikel (refereegranskat)abstract
- We measured the microvascular response to histamine in guinea pig skin. Histamine (40 mg ml-1) was given either as a skin prick test or applied topically onto a skin window. The skin window was prepared by applying suction and gentle warming to the skin so that a blister was formed, and by removing the top of the blister. The microvascular response was measured as the accumulation of radiolabelled transferrin in the skin in vivo, reflecting a combination plasma exudation and vasodilatation. In the control (saline) challenge, the response was slightly greater in the skin window than after skin prick challenge and the scatter was larger. Histamine challenge resulted in a significant microvascular response with respect to the control situation when measured immediately after provocation for both challenge techniques. Ten minutes after challenge, a smaller response was measured, which was still significantly greater than control for the skin prick challenge, but not for topical provocation using the skin window technique. We conclude that the microvascular response to histamine after provocation with the skin prick technique is similar to that after topical provocation using the skin window technique. The skin window technique may have a lower sensitivity than the skin prick technique owing to a higher scatter in the control situation. This difference should be considered when performing and interpreting studies of the microvascular reaction in the skin.
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| 28. |
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| 29. |
- Greiff, Lennart, et al.
(författare)
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Absorption across the nasal airway mucosa in house dust mite perennial allergic rhinitis.
- 2002
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 22:1, s. 55-57
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Tidskriftsartikel (refereegranskat)abstract
- House dust mite allergens express protease activity and it has been suggested that this property has pathogenic effects by increasing airway absorption. In accordance, house dust mite allergens may increase mucosal permeability in vitro. The objective of the present study was to examine nasal absorption of desmopressin (1-deamino-8-D-arginine vasopressin) in patients with perennial house dust mite allergic rhinitis and in healthy subjects in vivo. Patients with perennial allergic rhinitis were examined after a 4-week treatment withdrawal period, when symptoms of allergic rhinitis occurred, and healthy subjects were examined together with the patients. Desmopressin (20 microg ml(-1)) was moved into the nasal cavity using a nasal pool-device that contained 15 ml fluid. The fluid was kept in the nasal cavity for 15 min and then recovered. Urine was collected for 24 h after the nasal administration and the urinary excretion of desmopressin was determined as an index of nasal absorption. The urinary excretion of desmopressin was 1148+/-535 pmol 24 h(-1) in patients with perennial house dust mite allergic rhinitis and 1012+/-291 pmol 24 h(-1) in healthy subjects. We conclude that nasal airway absorption of the 1067 Da peptide desmopressin is unaffected in perennial house dust mite allergic rhinitis compared with healthy subjects.
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| 30. |
- Greiff, Lennart, et al.
(författare)
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Loss of size-selectivity at histamine-induced exudation of plasma proteins in atopic nasal airways.
- 2002
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 22:1, s. 28-31
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Tidskriftsartikel (refereegranskat)abstract
- Plasma proteins occur in the airway lumen in inflammatory airway diseases. This study tests the hypothesis that airway microvascular-epithelial exudation of plasma proteins, as induced by a non-injurious inflammatory mediator, is characterized by loss of size-selectivity. Using a nasal pool-device, the nasal mucosa of 10 allergic individuals, without current disease, was sequentially exposed to saline and histamine (40 and 400 microg ml(-1)). Nasal lavage fluid and blood-levels of albumin (69 kD) and alpha2-macroglobulin (720 kD) were determined. Histamine produced concentration-dependent exudation of albumin and alpha2-macroglobulin. The albumin/alpha2-macroglobulin concentration ratio of the saline lavage fluid (baseline) was 40+/-19. However, at the histamine challenges the ratios were 25+/-3 and 22+/-2, respectively, which did not differ from that of circulating plasma (22+/-2). We conclude that there is minor and size-selective luminal entry of plasma proteins at baseline. However, at concentration-dependent exudative responses to histamine, plasma proteins enter the airway lumen without being sieved. These data indicate that inflammatory stimulus-induced extravasation, lamina propria distribution and paracellular epithelial passage of plasma occur with minimal size-selectivity. Inferentially, the full immunological capacity of plasma proteins may readily be made available at the surface of human intact airway mucosa.
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| 34. |
- Hernandez-Andrade, Edgar, et al.
(författare)
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Lung fractional moving blood volume in normally grown and growth restricted foetuses.
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 24:2, s. 69-74
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine foetal lung blood perfusion using power Doppler ultrasound (PDU) and to compare fractional moving blood volume (FMBV) and mean pixel intensity (MPI) estimations in the lungs of normally grown (NG) foetuses and foetuses with intrauterine growth restriction (IUGR) and also to correlate foetal lung FMBV and MPI with respiratory complications after birth. Methods: Lungs of 47 NG and 25 IUGR foetuses after 32 weeks of gestation were examined with PDU. FMBV and MPI were estimated in a defined region in the posterior part of the foetal lung closest to maternal abdominal wall. FMBV and MPI were correlated to foetal weight deviation and gestational age. Perinatal outcome and respiratory complications after birth were recorded in both groups. Results: There were significantly lower FMBV and MPI values in IUGR than in NG foetuses. The overall variation was lower for FMBV than for MPI. There was a slightly higher correlation between FMBV and foetal weight deviation [r = 0·33, 95% confidence intervals (CI) 0·11-0·52] than between MPI and foetal weight deviation (r = 0·26, 95% CI 0·03-0·46). There was no significant correlation between FMBV or MPI and gestational age. No differences between the groups were found in the rate of respiratory complications, and they were not correlated either to the FMBV or MPI. Conclusion: FMBV and MPI, estimated from the PDU signals of foetal lung circulation, showed lower values in third-trimester pregnancies complicated by IUGR. The frequency of neonatal respiratory complications was not increased in cases with low pulmonary FMBV and MPI values.
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| 35. |
- Hertervig, Eva, et al.
(författare)
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Evidence for electrical remodelling of the atrial myocardium in patients with atrial fibrillation. A study using the monophasic action potential recording technique.
- 2002
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 22:1, s. 8-12
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Tidskriftsartikel (refereegranskat)abstract
- Experimental studies have shown that remodelling of the atrial myocardium is linked to the occurrence and perpetuation of atrial fibrillation (AF). Clinical evidence, however, is insufficient. We recorded monophasic action potentials (MAP) during AF from one to three sites in the right atrium in seven patients with chronic AF (CAF) and in 11 patients with paroxysmal AF (PAF). The fibrillatory (FF) interval between two consecutive upstrokes of the MAP was measured using a computer-assisted manual method. The mean, median, 15th, 10th, 5th percentile and shortest FF intervals were calculated in each patient and used as estimates of the local atrial effective refractory period (AERP) during AF. In three patients burst pacing at 400 and 500 beats min(-1) was delivered during the MAP recording. In nine patients, the AERP was also tested using the extra stimulus technique during sinus rhythm. RESULTS: Thirty-eight recordings were obtained. The shortest FF interval was significantly shorter in patients with CAF as compared with that in patients with PAF (50+/-13 vs. 72+/-31 ms, P<005). Similar differences were seen in the mean, median, 15th, 10th, and 5th percentile FF interval. The AERP during sinusrhythm was significantly longer than the estimated AERPs (P<0 05 to P<0.01) in the nine patients. There was no significant difference in FF interval before and after the burst pacing in the three patients. CONCLUSION: The AERP was significantly shortened during AF, as compared with that during sinus rhythm, and the AERP shortening was more marked in patients with CAF than in patients with PAF. These clinical findings support the connection between the electrical remodelling and the occurrence and/ or perpetuation of the AF.
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| 36. |
- Holmgren, Daniel, et al.
(författare)
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Syncope--an unusual presentation of ventricle dysfunction in a patient with Fontan circulation.
- 2003
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Ingår i: Clinical physiology and functional imaging. - 1475-0961. ; 23:2, s. 120-2
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Tidskriftsartikel (refereegranskat)abstract
- We report a case of recurrent syncope in association with moderate ventricular dysfunction and mild AV-valve regurgitation in an 18-year-old girl, 4 years after she underwent total cavopulmonary connection surgery. Cardiac catheterization revealed a transpulmonary gradient of 1-2 mmHg. During exercise, a dramatic fall in blood pressure and blood oxygenation was observed, paralleled by an increase in heart rate and central venous pressure. Although a slight increase in pulmonary vascular resistance could not be excluded, the reaction was interpreted in terms of an extremely low transpulmonary gradient in association with ventricular dysfunction. Five months after heart transplantation, the patient has been completely free from syncope. Fontan circulation usually involves a delicate haemodynamic situation which may necessitate haemodynamic re-evaluations, including dynamic measurements of the central venous pressure during exercise. Also a moderate ventricular dysfunction may result in compromised pulmonary circulation which in turn may lead to syncope during exercise as a result of insufficient systemic circulation.
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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Larsson, Marcus, et al.
(författare)
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Enhanced efficacy of porcine lung surfactant extract by utilization of its aqueous swelling dynamics.
- 2002
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 22:1, s. 39-48
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the interactions between a porcine lung surfactant (PLS) extract and distilled water, saline solution or Ringer solution. The phases which coexist in equilibrium with water or electrolyte solutions were analysed by X-ray diffraction and cryo transmission electron microscopy (cryo-TEM). A lamellar phase with a structure unit consisting of double bilayers was observed in water, whereas lamellar phases with the usual bilayer structure unit were formed in saline and in Ringer solutions. At 25 degrees C the presence of a 4.2-A peak in the X-ray diffraction wide-angle region of these three maximally swollen phases showed that most of the hydrocarbon chains were organized in a crystalline packing. At 42 degrees C the chains in all three phases were melted which, in combination with the low-angle diffraction, shows that they were liquid-crystalline. Polyhedral-like vesicles and spherically shaped multilamellar vesicles were observed in cryo-TEM. The bilayer unit structures were consistent with the periodicity seen by X-ray diffraction. The dynamic swelling behaviour was followed in the polarizing microscope. A remarkable growth of birefringent networks was seen at the air interface of samples swollen in Ringer solution and saline solution. No such interfacial growth phenomena were observed during swelling in water without electrolytes. Then, these dynamics were analysed in relation to time-dependent pulmonary administration of the surfactant extract in rats. Variation in the time of administration (20 and 60 min) after mixing the extract with saline or Ringer solution showed clear differences in physiological effects. At pulmonary administration when the swelling behaviour in vitro showed a maximum in dynamics, the arterial oxygenation was superior to that of administration at a time after a steady-state had been reached. This means that the clinical performance of mammalian lung surfactant extracts can be significantly improved by taking the time-dependent aqueous swelling of the extract into account.
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| 41. |
- Larsson, Marcus, et al.
(författare)
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Human SP-A and a pharmacy-grade porcine lung surfactant extract can be reconstituted into tubular myelin--a comparative structural study of alveolar surfactants using cryo-transmission electron microscopy.
- 2003
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 23:4, s. 199-203
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Tidskriftsartikel (refereegranskat)abstract
- Cryo-transmission electron microscopy (cryo-TEM) is a rather artefact-free method, well suited to study the alveolar surfactant system. A pharmacy grade porcine lung surfactant extract (HL-10) was mixed with human SP-A and Ringer's solution (for calcium ions), and it was shown by cryo-TEM that the tubular myelin (TM) type of structure was reconstituted. These aggregates were associated to liposomal aggregates, and resulted in macroscopic phase-separation. This phase showed a weak birefringence in the polarising microscope, which is characteristic for a liquid-crystalline type of structure. TM from rabbit lung lavage was also examined, and showed the same periodic arrangement of bilayers as alveolar surface layer from freshly cut rabbit lungs deposited directly on the cryo-TEM grids. The distance between the bilayers of TM was 40-50 nm, and an electron dense material, assumed to be SP-A, was sometimes seen to occur periodically along the bilayers, oriented perpendicularly to the tubuli. The results are consistent with the surface-phase model of the alveolar lining.
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| 42. |
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| 43. |
- Nihlén, Ulf, et al.
(författare)
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Nasal neutrophil activity and mucinous secretory responsiveness in COPD.
- 2003
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 23:3, s. 138-142
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Tidskriftsartikel (refereegranskat)abstract
- Patients with chronic obstructive pulmonary disease (COPD) frequently report nasal symptoms. In the present study, we have examined whether or not COPD is associated with any nasal inflammation. Plasma exudation evoked by histamine challenges has been employed to improve the recovery of inflammatory indices in nasal lavage fluids. In 23 COPD-patients and 26 healthy subjects, all without history or signs of allergic rhinitis, nasal polyposis, or chronic rhinosinusitis, nasal saline-lavages were performed with and without histamine. alpha2-Macroglobulin, fucose, eosinophil cationic protein (ECP) and myeloperoxidase (MPO) were determined as indices of plasma exudation, mucinous secretion, eosinophil activity and neutrophil activity, respectively. The difference in MPO-levels between the histamine and the saline lavage was greater in COPD patients compared with healthy subjects (P<0·05). Also, COPD patients reporting nasal symptoms presented an increase in MPO at histamine challenge (P<0·05, cf. saline) and greater differences in MPO and fucose, respectively, between the histamine and the saline lavage (P<0·05, cf. patients without symptoms). We conclude that COPD is not associated with any marked nasal inflammation. However, our observation on increased MPO-levels at histamine challenge suggests some degree of increased neutrophil activity in this condition. Furthermore, when associated with nasal symptoms, COPD may be associated with an increased nasal secretory responsiveness.
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| 44. |
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| 45. |
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| 46. |
- Olsson, Sven-Erik, et al.
(författare)
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Neural networks--a diagnostic tool in acute myocardial infarction with concomitant left bundle branch block.
- 2002
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 22:4, s. 295-299
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Tidskriftsartikel (refereegranskat)abstract
- The prognosis of acute myocardial infarction (AMI) improves by early revascularization. However the presence of left bundle branch block (LBBB) in the electrocardiogram (ECG) increases the difficulty in recognizing an AMI and different ECG criteria for the diagnosis of AMI have proved to be of limited value. The purpose of this study was to detect AMI in ECGs with LBBB using artificial neural networks and to compare the performance of the networks to that of six sets of conventional ECG criteria and two experienced cardiologists. A total of 518 ECGs, recorded at an emergency department, with a QRS duration > 120 ms and an LBBB configuration, were selected from the clinical ECG database. Of this sample 120 ECGs were recorded on patients with AMI, the remaining 398 ECGs being used as a control group. Artificial neural networks of feed-forward type were trained to classify the ECGs as AMI or not AMI. The neural network showed higher sensitivities than both the cardiologists and the criteria when compared at the same levels of specificity. The sensitivity of the neural network was 12% (P = 0.02) and 19% (P = 0.001) higher than that of the cardiologists. Artificial neural networks can be trained to detect AMI in ECGs with concomitant LBBB more effectively than conventional ECG criteria or experienced cardiologists.
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| 47. |
- Persson, Magnus, et al.
(författare)
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A new non-invasive ultrasonic method for simultaneous measurements of longitudinal and radial arterial wall movements: first in vivo trial.
- 2003
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 23:5, s. 247-251
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Tidskriftsartikel (refereegranskat)abstract
- During recent years, the radial movement of the arterial wall has been extensively studied, and measurements of the radial movement are now an important tool in cardiovascular research for characterizing the mechanical properties of the arterial wall. In contrast, the longitudinal movement of vessels has gained little or no attention as it has been presumed that this movement is negligible. With modern high-resolution ultrasound, it can, however, be seen that the intima-media complex of the arterial wall moves not only in the radial direction, but also in the longitudinal direction during pulse-wave propagation. This paper describes a new non-invasive ultrasonic method that is able to measure simultaneously two dimensionally arterial vessel wall movements. The method is demonstrated in a limited in vivo trial. Results from the in vivo trial show that, apart from the well-known radial movement, there is a distinct longitudinal movement in the human common carotid artery with, in this case, the intima-media complex moving substantially as compared with the region of the tunica adventitia. Two-dimensional evaluation of the vessel-wall movements, taking not only the radial movement, but also the longitudinal movement into account, may provide novel information of importance in the evaluation of vessel-wall function.
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| 48. |
- Pirhonen, JP, et al.
(författare)
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A longitudinat study of maternal oxygen saturation during short-term submaximal exercise
- 2003
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 23:1, s. 37-41
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Longitudinal prospective study before, during and after normal pregnancy of the effect of short-term submaximal exercise on maternal oxygen saturation. Methods: Fourteen healthy women were recruited to the study before a planned pregnancy, and were followed seven times during the pregnancy and for up to 6 month after delivery. A submaximal bicycle exercise test with a target heart rate of 85% of the predicted age-adjusted maximum was performed. Maternal oxygen saturation was continuously recorded using a pulse oximeter. Results: Maternal oxygen saturation at maximum work-load had increased significantly already at 8 weeks gestation compared with preconception levels, and remained at a significantly higher level until 29 weeks of gestation. Thereafter, the oxygen saturation continued to be higher even at 6 month postpartum. During the exercise test, the lowest saturation was found during the late recovery period, this remained unchanged before, during and after pregnancy. Conclusion: A pregnant woman responds to short-term exercise by increasing the oxygen saturation until 29 weeks. After that, the saturation level decreases but remains at a higher level even 6 month after delivery compared with preconception levels.
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| 49. |
- Strömvall-Larsson, Eva, 1952, et al.
(författare)
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Pulmonary gas exchange during exercise in Fontan patients at a long-term follow-up
- 2004
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Ingår i: Clin Physiol Funct Imaging. - 1475-0961. ; 24:6, s. 327-34
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Tidskriftsartikel (refereegranskat)abstract
- Desaturation during exercise in the Fontan type of circulation may be due to known right-to-left shunts in some patients, while in others there are no obvious signs of shunts. AIM: To evaluate the gas exchange and exercise capacity in patients with Fontan circulation. MATERIAL AND METHODS: Twenty patients with the Fontan type of circulation, median age at operation 7.5 years (3.0-35 years), follow-up time 12.1 years (8.3-20.4 years), were included. The intrapulmonary gas mixing (N(2)-slope) and diffusion capacity for carbon monoxide (D(LCO)) was evaluated and determination of cardiac output was performed at rest and during exercise with measurements of ventilation, oxygen uptake, respiratory rate, carbon dioxide production and heart rate. Samples for blood gases (P(a)O(2), S(a)O(2)) were obtained at rest and at the end of each work load. RESULTS: The median exercise capacity was 1.47 l min(-1). During exercise, all the patients had an alveolar-arterial oxygen partial pressure difference (P(A-a)O(2)) above 2 SD. Patients with known right-to-left shunts had lower P(a)O(2) and S(a)O(2) values and higher P(A-a)O(2) values both at rest, median 7.5 kPa, 90%, and 7.2 kPa, respectively, and during exercise, median 5.8 kPa, 77% and 10.1 kPa, compared with those with no shunts, median 11.2 kPa, 97% and 4.1, respectively, at rest and 9.7 kPa, 94%, and 6.3 during exercise (P<0.01). No correlation was found between cardiac index, the N(2)-slope or the D(LCO) at rest and the P(a)O(2) and S(a)O(2) at rest or during exercise. CONCLUSION: In patients with the Fontan type of circulation, right-to-left shunts are the major cause of desaturation during exercise.
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| 50. |
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