| 1. |
- Forssten, Maximilian Peter, 1996-, et al.
(författare)
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The Role of Glycerol-Containing Drugs in Cerebral Microdialysis : A Retrospective Study on the Effects of Intravenously Administered Glycerol
- 2019
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Ingår i: Neurocritical Care. - : Humana Press. - 1541-6933 .- 1556-0961. ; 30:3, s. 590-600
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cerebral microdialysis (CMD) is a valuable tool for monitoring compounds in the cerebral extracellular fluid (ECF). Glycerol is one such compound which is regarded as a marker of cell membrane decomposition. Notably, in some acutely brain-injured patients, CMD-glycerol levels rise without any other apparent indication of cerebral deterioration. The aim of this study was to investigate whether this could be due to an association between CMD-glycerol levels and the administration of glycerol-containing drugs.METHODS: Microdialysis data were retrospectively retrieved from the hospital's intensive care unit patient data management system (PDMS). All patients who were monitored with CMD for ≥ 96 h were included. Administered drug doses were retrieved from the PDMS and converted to exact doses of glycerol. Cross-correlation analyses were performed between the free, metabolized as well as total administered dose of glycerol and the detrended and differenced CMD-glycerol concentration. These analyses were repeated for two sets of subgroups based upon the individual catheter's graphical trend and its location in relation to the lesion.RESULTS: There was no significant correlation between the differenced CMD-glycerol levels and drug-administered glycerol. Furthermore, there was no significant correlation between CMD-glycerol and catheter location or graphical trend. However, if the CMD-glycerol levels were detrended, significant but clinically non-relevant correlations were identified (maximum correlation coefficient of 0.1 (0.04-0.15, 95% CI) at a lag of 7 h using the total administered dose of glycerol).CONCLUSIONS: Glycerol-containing drugs routinely administered intravenously in the clinical setting appear to have a minimal and clinically insignificant effect on levels of glycerol in the cerebral ECF.
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| 2. |
- Lindblad, Caroline, et al.
(författare)
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Fluid proteomics of CSF and serum reveal important neuroinflammatory proteins in blood-brain barrier disruption and outcome prediction following severe traumatic brain injury : a prospective, observational study
- 2021
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Ingår i: Critical Care. - : Springer Nature. - 1364-8535 .- 1466-609X. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Severe traumatic brain injury (TBI) is associated with blood-brain barrier (BBB) disruption and a subsequent neuroinflammatory process. We aimed to perform a multiplex screening of brain enriched and inflammatory proteins in blood and cerebrospinal fluid (CSF) in order to study their role in BBB disruption, neuroinflammation and long-term functional outcome in TBI patients and healthy controls. Methods: We conducted a prospective, observational study on 90 severe TBI patients and 15 control subjects. Clinical outcome data, Glasgow Outcome Score, was collected after 6-12 months. We utilized a suspension bead antibody array analyzed on a FlexMap 3D Luminex platform to characterize 177 unique proteins in matched CSF and serum samples. In addition, we assessed BBB disruption using the CSF-serum albumin quotient (Q(A)), and performed Apolipoprotein E-genotyping as the latter has been linked to BBB function in the absence of trauma. We employed pathway-, cluster-, and proportional odds regression analyses. Key findings were validated in blood samples from an independent TBI cohort. Results: TBI patients had an upregulation of structural CNS and neuroinflammatory pathways in both CSF and serum. In total, 114 proteins correlated with Q(A), among which the top-correlated proteins were complement proteins. A cluster analysis revealed protein levels to be strongly associated with BBB integrity, but not carriage of the Apolipoprotein E4-variant. Among cluster-derived proteins, innate immune pathways were upregulated. Forty unique proteins emanated as novel independent predictors of clinical outcome, that individually explained similar to 10% additional model variance. Among proteins significantly different between TBI patients with intact or disrupted BBB, complement C9 in CSF (p = 0.014, Delta R-2 = 7.4%) and complement factor B in serum (p = 0.003, Delta R-2 = 9.2%) were independent outcome predictors also following step-down modelling. Conclusions: This represents the largest concomitant CSF and serum proteomic profiling study so far reported in TBI, providing substantial support to the notion that neuroinflammatory markers, including complement activation, predicts BBB disruption and long-term outcome. Individual proteins identified here could potentially serve to refine current biomarker modelling or represent novel treatment targets in severe TBI.
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| 3. |
- Thelin, Eric Peter, et al.
(författare)
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Protein profiling in serum after traumatic brain injury in rats reveals potential injury markers
- 2018
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Ingår i: Behavioural Brain Research. - : Elsevier. - 0166-4328 .- 1872-7549. ; 340, s. 71-80
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The serum proteome following traumatic brain injury (TBI) could provide information for outcome prediction and injury monitoring. The aim with this affinity proteomic study was to identify serum proteins over time and between normoxic and hypoxic conditions in focal TBI. Material and methods: Sprague Dawley rats (n = 73) received a 3 mm deep controlled cortical impact ("severe injury"). Following injury, the rats inhaled either a normoxic (22% O-2) or hypoxic (11% O-2) air mixture for 30 min before resuscitation. The rats were sacrificed at day 1, 3, 7, 14 and 28 after trauma. A total of 204 antibodies targeting 143 unique proteins of interest in TBI research, were selected. The sample proteome was analyzed in a suspension bead array set-up. Comparative statistics and factor analysis were used to detect differences as well as variance in the data. Results: We found that complement factor 9 (C9), complement factor B (CFB) and aldolase c (ALDOC) were detected at higher levels the first days after trauma. In contrast, hypoxia inducing factor (HIF)1 alpha, amyloid precursor protein (APP) and WBSCR17 increased over the subsequent weeks. S100A9 levels were higher in hypoxic-compared to normoxic rats, together with a majority of the analyzed proteins, albeit few reached statistical significance. The principal component analysis revealed a variance in the data, highlighting clusters of proteins. Conclusions: Protein profiling of serum following TBI using an antibody based microarray revealed temporal changes of several proteins over an extended period of up to four weeks. Further studies are warranted to confirm our findings.
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| 4. |
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| 5. |
- Thelin, Peter, et al.
(författare)
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Analytical Calculation of the Airgap Flux Density of PM Synchronous Motors with Buried Magnets Including Axial Leakage, Tooth and Yoke Saturations
- 2000
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Ingår i: Proc. of the International Conference on Power Electronics and Variable Speed Drives, London, September 2000.. - : IEE. ; , s. 218-223
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Konferensbidrag (refereegranskat)abstract
- It has been shown earlier that the airgap flux density of PM motors with buried magnets can be calculated with a satisfactory result, if saturated iron bridges, axial leakage flux (from 2D-FEM) and teeth saturation are taken into account. In this paper, instead of using 2D-FEM, an analytical expression for the axial reluctance is derived. By including the saturation of rotor and stator yokes, the model is even further improved. The result is a complete analytical model, which takes into account all phenomena mentioned above, and improves the agreement with experimental values.
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| 6. |
- Thelin, Peter, et al.
(författare)
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Calculation of the Airgap Flux Density of PM Synchronous Motors with Buried Magnets including Axial Leakage and Teeth Saturation
- 1999
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Ingår i: Proc. of the Electrical Machines and Drives Conference, Canterbury, UK, September 1999. - : Institution of Electrical Engineers (IEE). ; , s. 339-345
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Konferensbidrag (refereegranskat)abstract
- It has been shown earlier that the airgap flux density of unsaturated PM motors with buried magnets can be calculated analytically, with a satisfactory result, compared to 2D-FEM calculations. By taking axial leakage flux, and stator and rotor teeth saturation into account an improved expression for the airgap flux density, showing better agreement with experiments, is obtained.
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| 7. |
- Thelin, Peter, et al.
(författare)
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Comparison between Different Ways to Calculate the Induced No-Load Voltage of PM Synchronous Motors using Finite Element Methods
- 2001
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Ingår i: Proc. of the 4th IEEE International Conference on Power Electronics and Drive Systems (PEDS'01), Bali, Indonesia, October 2001, vol. 2.. ; , s. 468-474
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Konferensbidrag (refereegranskat)abstract
- In this paper two different ways of calculating the induced no-load voltage of permanent magnet synchronous motors (PMSM), by the use of a finite element method (FEM) program, have been compared. Neither of the two calculation methods require a FEM software package that can perform time-stepping. The number of required static FEM-calculations is limited to just a few, or even to one. The calculations are performed on five motor geometries. The results are compared to values obtained from time-stepping FEM-calculations, and to the measured induced no-load voltages of the five manufactured prototype motors. It can be seen that the least time-consuming method is accurate enough in most of these cases. The exceptions, in this study, are when there are relatively large airgaps and/or when the stator teeth are saturated.
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| 8. |
- Thelin, Peter, et al.
(författare)
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Development and Efficiency Measurements of a Compact 15 kW 1500 r/min Integral Permanent Magnet Synchronous Motor
- 2000
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Ingår i: Proc. of the IEEE Industry Applications Society Annual Meeting, Roma, Italy, October 2000.. ; , s. 155-162
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Konferensbidrag (refereegranskat)abstract
- This paper presents the development of a 15 kW, 1500 r/min integral motor, with the same outer dimensions as an equivalent standard induction motor, but with the possibility of operating with speed control and at a higher efficiency. To make a compact integral motor, a permanent magnet rotor is used, the coils of the line-filter and the coil of the DC-link have been integrated with the stator core, only a small DC-link capacitor is employed, and the motor is controlled without a shaft sensor. Temperature and efficiency measurements on the manufactured prototype machine are performed and the results are very promising.
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| 9. |
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| 10. |
- Thelin, Peter, et al.
(författare)
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Rotor Cage Losses of an Inverter-Fed PMSM investigated with FEM
- 2003
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Ingår i: Proceedings of the European Conference on Power Electronics and Applications, EPE´03.
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Konferensbidrag (refereegranskat)abstract
- In the design of a compact inverter-fed buried permanent magnet synchronous motor, the high-frequency losses of the sparse rotor cage - which are difficult to predict - were assumed to be small. To investigate these ohmic high-frequency losses of the rotor cage, fixed-speed time-stepping 2D-FEM calculations have been carried out. The losses due to only the magnets, magnets and sinusoidal currents, high-frequency currents etc., and the actual currents are presented. The actual current wave-forms were obtained from measurements on the manufactured prototype motor.
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