| 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. |
- Aaltonen, H. L., et al.
(författare)
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Deposition of inhaled nanoparticles is reduced in subjects with COPD and correlates with the extent of emphysema : Proof of concept for a novel diagnostic technique
- 2018
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 38:6, s. 1008-1014
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Tidskriftsartikel (refereegranskat)abstract
- Background: The diagnosis of chronic obstructive pulmonary disease (COPD) is often based on spirometry, which is not sensitive to early emphysema. We have recently described a method for assessing distal airspace dimensions by measuring recovery of nanoparticles in exhaled air after a single-breath inhalation followed by breath-hold. Recovery refers to the non-deposited particle fraction. The aim of this study was to explore differences in the recovery of exhaled nanoparticles in subjects with COPD and never-smoking controls. A secondary aim was to determine whether recovery correlates with the extent of emphysema. Method: A total of 19 patients with COPD and 19 controls underwent three repeats of single-breath nanoparticle inhalation followed by breath-hold. Particle concentrations in the inhaled aerosol, and in an alveolar sample exhaled after breath-hold, were measured to obtain recovery. Findings: The patients with COPD had a significantly higher mean recovery than controls, 0·128 ± 0·063 versus 0·074 ± 0·058; P = 0·010. Also, recovery correlated significantly with computed tomography (CT) densitometry variables (P<0·01) and diffusing capacity for carbon monoxide (DL,CO; P = 0·002). Interpretation: Higher recovery for emphysema patients, relative to controls, is explained by larger diffusion distances in enlarged distal airspaces. The nanoparticle inhalation method shows potential to be developed towards a tool to diagnose emphysema.
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| 5. |
- Abrahamsson, Pernilla, et al.
(författare)
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Detection of myocardial ischaemia using surface microdialysis on the beating heart
- 2011
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 31:3, s. 175-181
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Tidskriftsartikel (refereegranskat)abstract
- Microdialysis (MD) can be used to study metabolism of the beating heart. We investigated whether microdialysis results obtained from epicardial (surface) sampling reflect acute changes in the same way as myocardial sampling from within the substance of the ventricular wall. In anaesthetized open-thorax pigs a coronary snare was placed. One microdialysis probe was placed with the sampling membrane intramyocardially (myocardial), and a second probe was placed with the sampling membrane epicardially (surface), both in the area which was made ischaemic. Ten minutes collection intervals were used for microdialysis samples. Samples from 19 pigs were analysed for lactate, glucose, pyruvate and glycerol during equilibration, baseline, ischaemia and reperfusion periods. For both probes (surface and myocardial), a total of 475 paired simultaneous samples were analysed. Results from analyses showed no differences in relative changes for glucose, lactate and glycerol during baseline, ischaemia and reperfusion. Surface microdialysis sampling is a new application of the microdialysis technique that shows promise and should be further studied.
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| 6. |
- Abrahamsson, Pernilla, et al.
(författare)
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Surface microdialysis sampling : a new approach described in a liver ischaemia model
- 2012
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley-Blackwell. - 1475-0961 .- 1475-097X. ; 32:2, s. 99-105
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Tidskriftsartikel (refereegranskat)abstract
- We recently have shown that samples from microdialysis (MD) probes placed on the surface of the heart reflect metabolic events in the myocardium. This new interesting observation challenges us to consider whether surface application of MD applies to other parenchymatous organs and their surfaces. In 13 anesthetized pigs, transient liver ischaemia was achieved by occlusion of arterial and venous inflow to the liver. Two probes on liver surface and two in parenchyma were perfused with a flow rate of 1 mu l per min (n = 13). An identical set-up was used for probes with a flow rate of 2 mu l per min (n = 9). Samples were collected for every 15-min period during 60 min of baseline, 45 min of ischaemia and 60 min of reperfusion. Lactate, glucose, pyruvate and glycerol were analysed in MD samples. We focused on relative changes in the present study. There was a strong agreement in relative lactate and glucose levels between probes placed on liver surface and those on parenchyma. No significant differences in relative changes in lactate and glucose levels were seen between samples from surface probes and probes in liver parenchyma during equilibration, baseline, ischaemia or reperfusion with a flow rate of 1 mu l per min. MD sampling applied on the liver surface is a new application area for the MD technique and may be used to monitor liver metabolism during both physiological and pathophysiological conditions.
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| 7. |
- Ahlander, Britt-Marie, 1954-, et al.
(författare)
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An echo-planar imaging sequence is superior to a steady-state free precession sequence for visual as well as quantitative assessment of cardiac magnetic resonance stress perfusion
- 2017
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Ingår i: Clinical Physiology and Functional Imaging. - : Blackwell Publishing. - 1475-0961 .- 1475-097X. ; 37:1, s. 52-61
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To assess myocardial perfusion, steady-state free precession cardiac magnetic resonance (SSFP, CMR) was compared with gradient-echo-echo-planar imaging (GRE-EPI) using myocardial perfusion scintigraphy (MPS) as reference.METHODS: Cardiac magnetic resonance perfusion was recorded in 30 patients with SSFP and in another 30 patients with GRE-EPI. Timing and extent of inflow delay to the myocardium was visually assessed. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated. Myocardial scar was visualized with a phase-sensitive inversion recovery sequence (PSIR). All scar positive segments were considered pathologic. In MPS, stress and rest images were used as in clinical reporting. The CMR contrast wash-in slope was calculated and compared with the stress score from the MPS examination. CMR scar, CMR perfusion and MPS were assessed separately by one expert for each method who was blinded to other aspects of the study.RESULTS: Visual assessment of CMR had a sensitivity for the detection of an abnormal MPS at 78% (SSFP) versus 91% (GRE-EPI) and a specificity of 58% (SSFP) versus 84% (GRE-EPI). Kappa statistics for SSFP and MPS was 0·29, for GRE-EPI and MPS 0·72. The ANOVA of CMR perfusion slopes for all segments versus MPS score (four levels based on MPS) had correlation r = 0·64 (SSFP) and r = 0·96 (GRE-EPI). SNR was for normal segments 35·63 ± 11·80 (SSFP) and 17·98 ± 8·31 (GRE-EPI), while CNR was 28·79 ± 10·43 (SSFP) and 13·06 ± 7·61 (GRE-EPI).CONCLUSION: GRE-EPI displayed higher agreement with the MPS results than SSFP despite significantly lower signal intensity, SNR and CNR.
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| 8. |
- Ahlund, Catherine, et al.
(författare)
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Pulse wave analysis on fingertip arterial pressure : effects of age, gender and stressors on reflected waves and their relation to brachial and femoral artery blood flow
- 2008
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 28:2, s. 86-95
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Analysis of the contour of the arterial pressure pulse (pulse wave analysis; PWA) adds information about arterial stiffness etc., beyond that obtained from absolute pressures. Peripheral pulses normally show an anterograde systolic peak and two reflected peaks: one in systole and one in diastole. The amplitudes and timings of these were estimated from finger pressure recordings in three study groups. We studied the usefulness of continuous digital pressures for PWA. METHODS: First, PWA from intra-arterial (brachial) and non-invasive finger pressure recordings was compared. Secondly, stress-induced (mental arithmetics and cold pressor test) changes in pressure pulse reflection were compared with blood flow changes in brachial and femoral arteries (ultrasound). Thirdly, the influence of age and gender on digital pulse pressures was investigated at rest and during exercise. RESULTS AND CONCLUSION: Pulse wave analysis results from brachial and digital pressures correlated strongly. Stress induced changes in systolic reflection were associated with changes in brachial artery flow patterns, whereas diastolic reflection was associated with femoral artery flow changes. At rest, age increased systolic reflection without affecting diastolic reflection. Exercise increased systolic reflection and reduced diastolic reflection more in older subjects (>40 years) than in younger (<40 years). In conclusion, PWA from continuous, digital pressure recordings is a convenient technique to study the arterial function at rest and during exposure to stressors in broad populations. The two reflected waves are differently regulated, which may indicate different anatomical origin.
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| 9. |
- Ahmeti, Artan, et al.
(författare)
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Prognostic value of left atrial volume index in acute coronary syndrome : A systematic review and meta-analysis
- 2021
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Ingår i: Clinical Physiology and Functional Imaging. - : John Wiley & Sons. - 1475-0961 .- 1475-097X. ; , s. 128-135
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Tidskriftsartikel (refereegranskat)abstract
- Background: In the absence of mitral valve disease, increased left atrial volume (LAV) is a marker of diastolic dysfunction and long-standing elevated left ventricle (LV) pressure. The aim of this study was to assess the role of increased baseline LAV in predicting clinical outcome of patients presenting with acute coronary syndrome (ACS).Methods: We systematically searched all electronic databases up to September 2020 in order to select clinical trials and observational studies, which assessed the predictive role of LAV indexed (LAVI) on clinical outcome in patients with ACS. Primary clinical endpoints were as follows: major adverse cardiac events (MACE), all-cause mortality and hospitalization. Secondary endpoints were in-hospital complications.Results: A total of 2,705 patients from 11 cohort studies with a mean follow-up 18.7 +/- 9.8 months were included in the meta-analysis. Patients with low LAVI had low risk for MACE (15.9% vs. 33.7%; p < .01), long-term all-cause mortality (9.14% vs. 18.1%; p < .01), short-term mortality (3.31% vs. 9.38%; p = .02) and lower hospitalization rate (11.6% vs. 25.5%; p < .01) compared to patients with increased LAVI. Atrial fibrillation and cardiogenic shock as in-hospital events were lower (p < .05 for all) in patients with low LAVI but ventricular fibrillation/tachycardia was not different between groups (p = .14).Conclusion: Increased LAVI is an independent predictor of outcome in patients with ACS. Thus, assessment of LA index in these patients is important for better risk stratification and guidance towards optimum clinical management.
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| 10. |
- Aneq Åström, Meriam, et al.
(författare)
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Determination of right ventricular volume and function using multiple axially rotated MRI slices
- 2011
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Ingår i: Clinical Physiology and Functional Imaging. - : Blackwell Publishing Ltd. - 1475-0961 .- 1475-097X. ; 31:3, s. 233-239
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Tidskriftsartikel (refereegranskat)abstract
- Pandgt;Background: The conventional magnetic resonance imaging (MRI) method for right ventricular (RV) volume and motion, using short-axis (SA) orientation, is limited by RV anatomy and shape. We suggest an orientation based on six slices rotated around the long axis of the RV, rotated long axis (RLA). Materials and methods: Three phantoms were investigated in SA and RLA using cine balanced steady-state free precession MRI. Volumes were calculated based on segmentation and checked against true volumes. In 23 healthy male volunteers, we used six long-axis planes from the middle of the tricuspid valve to the RV apex, rotated in 30 degrees increments. For comparison, short-axis slices were acquired. Imaging parameters were identical in both acquisitions. Results: Right ventricular end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV) determined in the RLA 179 center dot 1 +/- 29 center dot 3; 80 center dot 1 +/- 17 center dot 1; 99 center dot 3 +/- 16 center dot 9 ml and in the SA were 174 center dot 0 +/- 21 center dot 1; 78 center dot 8 +/- 13 center dot 6; 95 center dot 3 +/- 14 center dot 5 ml with P-values for the difference from 0 center dot 17 to 0 center dot 64 (ns). Interobserver variability ranged between 3 center dot 2% and 6 center dot 6% and intraobserver variability between 2 center dot 8% and 6 center dot 8%. In SA views, consensus for the definition of the basal slice was necessary in 39% of the volunteers for whom the average volume change was 20% in ESV and 10% in EDV. Conclusions: The RLA method results in better visualization and definition of the RV inflow, outflow and apex. Accurate measurement of RV volumes for diagnosis and follow-up of cardiac diseases are enhanced by the RLA orientation, even though additional acquisition time is required.
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