Biomedical subjects

S Kjellström

Publications and source records attributed to S Kjellström.

5 recordsLinked to original sources

PubMed2006

Retinal function and histopathology in rabbits treated with Topiramate.

PURPOSE: To evaluate retinal function and histopathology in rabbits treated orally with the anti-epileptic drug topiramate. METHODS: Six rabbits were treated with a daily oral dose of topiramate during a period of eight months. Six rabbits receiving water served as controls. Blood samples were analyzed for determination of topiramate serum levels in order to ensure successful drug exposition. Standardized full-field electroretinograms (ERGs) were performed before treatment and then at 2, 3 and 8 months during the treatment period. After terminating treatment the rabbits were sacrificed and the morphology of the sectioned retina was studied. RESULTS: After eight months of treatment the full-field ERG demonstrated normal rod function in treated and control rabbits, but the light adapted 30 Hz flicker b-wave amplitude was significantly reduced in the treated rabbits. This was the case for both the light adapted (Wilcoxon signed ranks test, P = 0.046) and the dark adapted (Wilcoxon signed ranks test, P = 0.028) 30 Hz flicker response from the treated rabbits. Retinal immunohistology revealed a severe accumulation of GABA in amacrine cells and in the inner plexiform layer in 4 of 6 treated rabbits compared to the controls. CONCLUSIONS: Topiramate, orally administrated to rabbits, may cause a significant reduction of the retinal function demonstrated by the reduced b-wave amplitude in the full-field ERG, as well as changes in immunohistology characterized by a severe accumulation of GABA in the inner retina. The retinal dysfunction and the morphological changes indicate that topiramat may damage the retina, similarly to vigabatrin (another anti-epileptic drug).

Adaptation, Ocular↗

PubMed2000

Flow immunochemical bio-recognition detection for the determination of interleukin-10 in cell samples.

On- and off-line heterogeneous non-competitive flow immunoassays for the determination of Interleukin-10 are described. The sample containing IL-10 is mixed, either on-line in a reaction coil or off-line in a test tube, with fluorescent labelled anti-IL-10 antibodies to form an antibody-antigen complex. The labelled unbound antibodies are trapped on an immobilized IL-10 column whereas the IL-10-antibody complexes are eluted and detected downstream by a fluorescence detector. The optimization of the systems was performed with respect to choice of affinity support, flow rate, carrier buffer additives, pH and antibody-antigen association. Both bio recognition assays were tested with a spiked cell medium and the IL-10 detection limits in this matrix was found to be 8 fmol using the off-line incubation mode and 40 fmol using the on-line incubation mode. The sample through-put was 26 and 40 samples per hour in the on-line and off-line incubation modes, respectively. IL-10 identification in the sample fractions was achieved using MALDI-TOF MS.

Antigen-Antibody Reactions↗

PubMed2000

Protein identification platform utilizing micro dispensing technology interfaced to matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

An integrated protein microcharacterization/identification platform has been developed. The system has been designed to allow a high flexibility in order to tackle challenging analytical problems. The platform comprises a cooled microautosampler, an integrated system for microcolumn HPLC, and a capillary reversed-phase column that is interfaced to matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) system via a low internal volume flow-through microdispenser. The chromatographic separation is continuously transferred onto a MALDI target plate as discrete spots as the dispenser ejects bursts of droplets of the column effluent in a precise array pattern. A refrigerated microfraction collector was coupled to the outlet of the flow-through microdispenser enabling enrichment and re-analysis of interesting fractions. The use of target plates pre-coated with matrix simplified and increased the robustness of the system. By including a separation step prior to the MALDI-TOF-MS analysis and hereby minimizing suppression effects allowed us to obtain higher sequence coverage of proteins compared to conventional MALDI sample preparation methodology. Additionally, synthetic peptides corresponding to autophosphorylated forms of the tryptic fragment 485-496 (ALGADDSYYTAR) of tyrosine kinase ZAP-70 were identified at sensitivities reaching 150 amol.

Amino Acid Sequence↗

PubMed2000

Development of an offline noncompetitive flow immunoassay for the determination of interleukin-8 in cell samples.

A noncompetitive flow immunoassay system (FIA) for the analysis of interleukin-8 (IL-8) in cell samples was developed. Affinity interaction assays based on offline incubation of excess labeled antibodies and antigen (IL-8) were carried out. The residual unbound labeled antibody was trapped in an immunoaffinity column with immobilized IL-8 while the immunocomplex, labeled antibody/IL-8, was detected by a fluorescence detector. Two fluorophores, FLUOS and Cy5.5, were conjugated with IL-8 antibody. Optimization and comparison between the two fluorescent labeled antibodies were performed with regard to pH, antibody concentration, flow rate, injection volume, and association time. Additionally, a horseradish peroxidase enzyme label was used for the conjugation to the anti-IL-8. The enzyme substrate reaction was optimized with respect to temperature and length of the substrate reaction coil. The detection limits were found to be 200 amol using the FLUOS-labeled anti-IL-8 and 1 fmol using the Cy5.5 fluorescence label. The developed FIA technique was applied for the analysis of IL-8 in cell samples. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to identify IL-8 in the cell samples.

Antibodies↗

PubMed1998

On-line coupling of microdialysis sampling with liquid chromatography for the determination of peptide and non-peptide leukotrienes.

An automated on-line sampling method was developed using microdialysis as the simultaneous sampling and sample pre-treatment technique. The extraction fraction values of microdialysis probes sampling different eicosanoids were investigated. The impact of cyclodextrins in the perfusion liquid used for sampling hydrophobic eicosanoids in biological systems was also studied. The total time for one analysis was 7.6 min allowing seven measurements per hour for monitoring kinetic changes in biological systems.

Autoanalysis↗