| 1. |
- Nilsson, Leif, et al.
(författare)
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Eosinophil granule proteins is cardiopulmonary bypass with and without heparin coating
- 1995
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Ingår i: Annals of Thoracic Surgery. - : Elsevier BV. - 0003-4975 .- 1552-6259. ; 59:3, s. 713-716
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Tidskriftsartikel (refereegranskat)abstract
- Extracorporeal circulation with exposure of blood to foreign surfaces causes activation of different defense systems, eg, white cells. Several potent mediators are released into plasma, capable of causing harmful effects to different organs, contributing to postoperative morbidity after operations using cardiopulmonary bypass. The eosinophil granulocyte has not previously been investigated in this respect. We studied two of its activation products, eosinophil cationic protein and eosinophil protein X in coronary bypass patients. In 17 control patients, plasma levels of eosinophil cationic protein and eosinophil protein X increased considerably during cardiopulmonary bypass. In 19 patients with heparin-coated cardiopulmonary bypass equipment the levels were significantly reduced, indicating improved biocompatibility of the cardiopulmonary bypass circuit. The heparin-coated surface causes less activation of eosinophils; also released eosinophil cationic protein is bound to the heparinized surface.
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| 2. |
- Peterson, Stefan, et al.
(författare)
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Endemic goitre in Guinea
- 1995
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Ingår i: The Lancet. ; 345:8948, s. 513-514
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Tidskriftsartikel (refereegranskat)
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| 3. |
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| 4. |
- Peterson, Stefan
(författare)
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Filtering and Wavelet Regression Methods with Application to Exercise ECG
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The analysis of the recorded electrical activity of the heart during an exercise test is a valuable method for investigating a patient's circulatory and respiratory system. But the disturbances that occurr during a test often make it difficult to interpret the signal in order to detect changes evoked by the increased workload and related to for instance coronary artery diseases. Suppression of disturbances are therefore necessary and in the first part of the thesis this is performed by estimation via a Kalman filtering based method where models with components from time series analysis are constructed both for the profile related to the electrical activity of the heart and the disturbances in the exercise ECG signal. The estimated models are evaluated on real datasets. The second part of this thesis introduces two new methods for signal representation and nonparametric regression. The advantages of these methods are that they are fast, adaptive and essentially automatic. As shown by examples can for instance ECG signals be effectively 'denoised'. The first method is based on a multiple wavelet extension of the standard Haar wavelet. This method basically uses a class of Haar wavelet matrices with maximum number of vanishing moments, the Chebyshev system of orthogonal polynomials. When used with the Stationary Wavelet Transform (SWT), also described in the thesis, they performed well in a simulation study when compared to the classic dyadic wavelet bases. Finally a robust nonparametric, wavelet inspired regression method is proposed. It is based on recursive subtractions by robust location estimators. A paramatric bootstrap method is proposed in order to estimate a signal contaminated with outliers. Robustness and performance of this method are studied in a simulation.
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| 5. |
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| 6. |
- Peterson, Stefan, et al.
(författare)
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Practice variation in Swedish primary care
- 1997
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Ingår i: Scandinavian Journal of Primary Health Care. - : Informa UK Limited. - 0281-3432 .- 1502-7724. ; 15:2, s. 68-75
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Tidskriftsartikel (refereegranskat)abstract
- Objective - To study individual practice patterns of physicians working in primary health care for standardized simulated cases on their first visit, and relate them to resource consumption for diagnostic tests, drugs and sick leave from a combined perspective of the health care and social security systems. Design - Postal questionnaire presenting six hypothetical working-age cases with symptoms of ailments common in primary care asking physicians to order diagnostic tests and procedures, drugs, follow-up appointments and sick pay. Setting - Swedish primary health care centres. Subjects - Two hundred randomly selected physicians. Main outcome measures - Activities taken by the physician - diagnostic and laboratory tests ordered, drugs prescribed, length of sick leave and the cost of these actions. Results - Practice patterns varied considerably, corresponding to a six-fold difference in total cost between the “cheapest” and “most expensive” physician. The largest share was loss of production as estimated by the cost of prescribed sick leave. Physicians who practised further away from hospitals and those who had worked more years tended to prescribe more measures. However, this only explained a small portion of the observed variation, which may be due to different physician attitudes to taking risks. Conclusion - ‘Paper’ cases of common medical ailments presented to primary care physicians revealed considerable differences in practice style, resulting in six-fold differences in cost of measures prescribed at first visits.
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