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| 13. |
- Apelqvist, G, et al.
(författare)
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Dynamic and kinetic effects of chronic citalopram treatment in experimental hepatic encephalopathy
- 2000
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Ingår i: Clinical neuropharmacology. - : Ovid Technologies (Wolters Kluwer Health). - 0362-5664 .- 1537-162X. ; 23:6, s. 304-317
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Tidskriftsartikel (refereegranskat)abstract
- Chronic hepatic encephalopathy (HE) is a neuropsychiatric syndrome that arises in liver-impaired subjects. Patients with HE display various neuropsychiatric symptoms including affective disturbances and may therefore likely receive treatment with novel thymoleptics like citalopram (CIT). The simultaneous pharmacokinetic and pharmacodynamic outcome of the commonly used serotonin-selective thymoleptic drugs in liver-impaired subjects with pending chronic HE is far from understood today. We therefore investigated the effects of chronic, body-weight-adjusted (10 mg ╖ kg-1 ╖ day-1), treatment with CIT in rats with and without portacaval shunts (PCS). Open-field activity was monitored. The 5-HT, 5-HIAA, noradrenaline (NA), and dopamine (DA) output were assessed in the frontal neocortex. The racemic levels of CIT and its metabolites DCIT and DDCIT, including the S- and R-enantiomers, were determined in serum, brain parenchyma, and extracellular fluid. The rats with PCS showed higher (2-3-fold) levels of CIT than rats undergoing a sham treatment with CIT in all compartments investigated. The PCS rats also showed elevated levels of DCIT and DDCIT. No major differences in the S/R ratios between PCS rats and control rats could be detected. The CIT treatment resulted in neocortical output differences between PCS rats and control rats mainly within the 5-HT and DA systems but not within the NA system. For the 5-HT system, this change was further evidenced by outspoken elevation in 5-HT output after KCl-depolarizing challenges. Moreover, the CIT treatment to PCS rats was shown to "normalize" the metabolic turnover of 5-HT, measured as a profound lowering of a basal elevation in the 5-HIAA levels. The CIT treatment resulted in an increased or "normalized" behavioral activity in the PCS group. Therefore, a dose-equal chronic treatment with CIT in PCS rats produced pharmacokinetic and pharmacodynamic changes not observed in control rats. The results further support the contention of an altered 5-HT neurotransmission prevailing in the chronic HE condition. However, the tentatively beneficial behavioral response also seen following chronic CIT treatment to PCS rats in this study has to be viewed in relation to both the pharmacokinetic and pharmacodynamic changes observed.
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| 14. |
- Bengtsson, Anders, et al.
(författare)
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Activation of type I interferon system in systemic lupus erythematosus correlates with disease activity but not with antiretroviral antibodies
- 2000
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Ingår i: Lupus. - : SAGE Publications. - 0961-2033 .- 1477-0962. ; 9:9, s. 664-671
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Tidskriftsartikel (refereegranskat)abstract
- The objective was to investigate the relation between serum levels of interferon-alpha (IFN-alpha), the activity of an endogenous IFN-alpha inducing factor (SLE-IIF), clinical and immunological disease activity as well as serum levels of antiretroviral antibodies in SLE. Serum levels of IFN-alpha were measured in serial sera from 30 patients sampled at different stages of disease activity (SLEDAI score). The SLE-IIF activity was measured by its ability to induce IFN-alpha production in cultures of normal peripheral blood mononuclear cells. Both serum IFN-alpha and SLE-IIF increased markedly at flare in serially followed patients. The SLEDAI score, levels of anti-dsDNA antibodies and IL-10 correlated positively, and complement components Clq, C3 and leukocytes correlated inversely with serum concentrations of IFN-alpha. The extent of multiple organ involvement correlated with serum IFN-alpha. No relation between concentrations of retroviral peptide binding antibodies and IFN-alpha or SLE-IIF activity was found. The close relationship between disease activity in SLE patients and IFN-alpha serum levels suggests that activation of the type 1 IFN system might be of importance in the disease process.
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| 16. |
- Bengtsson, Johan, et al.
(författare)
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System Identification of Homogenous Charge Compression Ignition (HCCI) Engine Dynamics
- 2004
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Ingår i: Advances in Automotive Control. - 0080442501 ; 37:22, s. 37-37
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Konferensbidrag (refereegranskat)abstract
- Homogeneous Charge Compression Ignition (HCCI) combustion lacksdirect ignition timing control, instead the auto ignition depends on the operatingcondition. Since auto ignition of a homogeneous mixture is very sensitive tooperating condition a fast combustion timing control is necessary for reliableoperation, the ignition timing control design requiring appropriate modelsand system output variables for its feedback design. This paper demonstratesthe use of system modeling and identification as a means to find modelsrelevant to the engine control. The identification methods used were varioussubspace-based methods. An LQG controller was designed based on the estimatedmodels and tested on a six-cylinder heavy duty engine running in HCCI operation.
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| 19. |
- Bobba, A. G., et al.
(författare)
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Application of environmental models to different hydrological systems
- 2000
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Ingår i: Ecological Modelling. - 0304-3800. ; 125:1, s. 15-49
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Tidskriftsartikel (refereegranskat)abstract
- In recent years global problems such as climatic change, acid rain, and water pollution in surface and subsurface environments dominate discussions of world environmental problems. In this paper, the roles of hydrologic processes and hydrogeochemical processes are investigated through development, modification, and application of mathematical models for addressing point and non-point source water quality modelling of receiving waters: surface water, subsurface water and lake water. The paper describes the use of models to simulate the movements of pollutants and water: subsurface water, surface water and lake sediments. A hydrological model was applied to Northeast Pond River watershed to understand climate change effects in the watershed. Four watershed acidification models were applied to compute hydrogen ion, alkalinity and sulphate concentrations from Turkey Lakes watershed, Canada. The computed hydrogen ion was used to estimate acidic events, magnitude of hydrogen ion, and duration using a stochastic model. There exist uncertainties in environmental models due to imperfect knowledge of processes controlling water quality parameters as well as errors in data. Monte Carlo, first order, and inverse method analyses were used to assess uncertainty in models. SUTRA (saturated-unsaturated transport) and SUTRA(-1) models were applied to Lambton county, Ontario, Canada to locate groundwater discharge areas for St. Clair River, calculate discharge rates, and hydrogeologic parameters. A sediment contamination model was developed and applied to Great Lakes sediment data to estimate transport parameters by Pb-210 data. It was then coupled with fatty acid data and results were compared with observed data. A contaminant transport model was developed and applied to two North American streams to compute stream water concentration. The computed data was compared with observed data using a simple statistical method. A hydrological model was coupled with water quality models and RAISON (regional analysis by intelligent systems on) expert system and applied to Canadian watersheds. Digital satellite data was used to locate groundwater discharge and recharge areas in the watershed. This data is useful as observed data for hydrological modelling and GIS (Geographical Information System) system. (C) 2000 Elsevier Science B.V. All rights reserved.
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| 20. |
- Dalén, T, et al.
(författare)
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Inflammatory mediators in autotransfusion drain blood after knee arthroplasty, with and without leucocyte reduction.
- 2003
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Ingår i: Vox sanguinis. - 0042-9007. ; 85:1, s. 31-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate whether leucocyte-reducing filters influenced complement activation and the formation of pro-inflammatory cytokines in autotransfusion drain blood after knee arthroplasty. MATERIALS AND METHODS: Twenty-three patients undergoing knee arthroplasty were divided into two groups. All patients were given salvage blood postoperatively. In Group A, a leucocyte filter was connected between the wound and the drain blood container. In Group B the drain blood was not leucocyte filtered. Complement split products and cytokines were analysed in circulating blood and in drain blood, together with blood-cellular differential counts. RESULTS: Drain blood showed activation vs. venous blood, with elevated concentrations of C3a, SC5b-9, interleukin (IL)-6, IL-8, polymorphonuclear (PMN) elastase and tumour necrosis factor-alpha (TNF-alpha) (P<0.05 to P<0.001). The leucocyte filter reduced TNF-alpha (P<0.01), but triggered complement activation (P<0.05). Room-temperature incubation increased the concentration of IL-8 (P<0.01), which was seen in both venous and drain blood. The leucocyte filter prevented formation of IL-8 (P<0.01). In drain blood at 24 h the inflammatory reactions accelerated (P<0.05-0.001), although the filter reduced the leucocyte counts and TNF-alpha concentrations. CONCLUSIONS: The leucocyte filter reduced IL-8 and TNF-alpha in drain blood, but at the same time triggered complement activation. Incubation affected the inflammatory spectrum of both drain blood and control venous blood, and the filtering reduced this activation.
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