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- Andersson, L., et al.
(author)
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Effect of CO2 pneumoperitoneum on ventilation-perfusion relationships during laparoscopic cholecystectomy
- 2002
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In: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 46:5, s. 552-560
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Journal article (peer-reviewed)abstract
- Background: Previous studies have shown that pneumoperitoneum transiently reduces venous admixture as assessed by a calculation based on the shunt formula, and increases arterial oxygen tension (PaO2) in patients without heart or lung disease. The aim of the present study was to further explore the relationship between ventilation-perfusion ((V) over dot (A)/(Q) over dot) before and during pneumoperitoneum by using the multiple inert gas technique. Methods: Nine patients without heart or lung disease (ASA I), with a mean age of 42 years, scheduled for laparoscopic cholecystectomy were included. After premedication and induction of anaesthesia, radial artery and pulmonary artery catheters were introduced percutaneously. The (V) over dot (A)/(Q) over dot relationships were evaluated by the multiple inert gas elimination technique before and during pneurnoperitoneum to obtain a direct measure of the pulmonary shunt. Results: Induction of pneumoperitoneum decreased the pulmonary shunt from 5.8 (4.5) to 4.1 (3.2)% (P<0.05) and increased PaO2 from 21.7 (5.9) to 24.7 (4.8) kPa (P<0.01). During surgery, the shunt increased from 3.2 (2.8) to 5.2 (3.4)% to the same level as before pneumoperitoneum induction. No area with low (V) over dot (A)/(Q) over dot was seen. Dead space ventilation amounted to 20.0 (1.2)% in the supine position and did not change during the investigation. Conclusions: In patients without heart or lung disease, pneumoperitoneum at an intra-abdominal pressure level of 11-13 mmHg- causes a transient reduction of the pulmonary shunt. The mechanisms underlying the present finding remain to be elucidated.
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- Madler, C.F., et al.
(author)
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Non-invasive diagnosis of coronary artery disease by quantitative stress echocardiography : Optimal diagnostic models using off-line tissue Doppler in the MYDISE study
- 2003
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In: European Heart Journal. - 0195-668X .- 1522-9645. ; 24:17, s. 1584-1594
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Journal article (peer-reviewed)abstract
- Aims: To develop optimal methods for the objective non-invasive diagnosis of coronary artery disease, using myocardial Doppler velocities during dobutamine stress echocardiography. Methods and results: We acquired tissue Doppler digital data during dobutamine stress in 289 subjects, and measured myocardial responses by off-line analysis of 11 left ventricular segments. Diagnostic criteria developed by comparing 92 normal subjects with 48 patients with coronary disease were refined in a prospective series of 149 patients referred with chest pain. Optimal diagnostic accuracy was achieved by logistic regression models, using systolic velocities at maximal stress in 7 myocardial segments, adjusting for independent correlations directly with heart rate and inversely with age and female gender (all p<0.001). Best cut-points from receiveroperator curves diagnosed left anterior descending, circumflex and right coronary disease with sensitivities and specificities of 80% and 80%, 91% and 80%, and 93% and 82%, respectively. All models performed better than velocity cut-offs alone (p<0.001). Conclusion: Non-invasive diagnosis of coronary artery disease by quantitative stress echocardiography is best performed using diagnostic models based on segmental velocities at peak stress and adjusting for heart rate, and gender or age. © 2003 Published by Elsevier Ltd on behalf of The European Society of Cardiology.
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- Bloom, O, et al.
(author)
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Colocalization of synapsin and actin during synaptic vesicle recycling
- 2003
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In: The Journal of cell biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 161:4, s. 737-747
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Journal article (peer-reviewed)abstract
- It has been hypothesized that in the mature nerve terminal, interactions between synapsin and actin regulate the clustering of synaptic vesicles and the availability of vesicles for release during synaptic activity. Here, we have used immunogold electron microscopy to examine the subcellular localization of actin and synapsin in the giant synapse in lamprey at different states of synaptic activity. In agreement with earlier observations, in synapses at rest, synapsin immunoreactivity was preferentially localized to a portion of the vesicle cluster distal to the active zone. During synaptic activity, however, synapsin was detected in the pool of vesicles proximal to the active zone. In addition, actin and synapsin were found colocalized in a dynamic filamentous cytomatrix at the sites of synaptic vesicle recycling, endocytic zones. Synapsin immunolabeling was not associated with clathrin-coated intermediates but was found on vesicles that appeared to be recycling back to the cluster. Disruption of synapsin function by microinjection of antisynapsin antibodies resulted in a prominent reduction of the cytomatrix at endocytic zones of active synapses. Our data suggest that in addition to its known function in clustering of vesicles in the reserve pool, synapsin migrates from the synaptic vesicle cluster and participates in the organization of the actin-rich cytomatrix in the endocytic zone during synaptic activity.
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| 9. |
- Brodin, L A, et al.
(author)
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[Hopeful future for echocardiography. Progress within both the function and perfusion areas].
- 2000
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In: Läkartidningen. - 0023-7205 .- 1652-7518. ; 97:46, s. 5302-4, 5307
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Journal article (peer-reviewed)abstract
- Echocardiography is presently a feasible method for quantitative estimation of intracardiac flows, pressure levels and for hemodynamic evaluation of valvular disease. The evaluation of regional myocardial function is still based on subjective scrutiny, and no routine method for the estimation of myocardial blood flow is available. We present an overview of newly developed techniques that are beginning to gain purchase in clinical practice. The use of native second harmonic imaging to improve image quality and of tissue Doppler to provide objective measurements of regional myocardial function is discussed. This article describes the transformation of tissue Doppler information into parametric images as in strain rate imaging, and overviews the use of ultrasound contrast agents. Used together with new imaging modalities, myocardial contrast echocardiography holds promise for future quantification of myocardial blood volume and flow. Other emerging echocardiographic technologies discussed are non-invasive measurement of coronary flow reserve and three dimensional cineloop visualization, developed to increase our understanding of cardiovascular physiological and anatomical coupling.
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