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- Andersson, Mikael, et al.
(författare)
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Characterization of the Chemical and Functional Stability of DEAE Sepharose Fast Flow
- 1993
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Ingår i: Process Biochemistry. - 1359-5113 .- 1873-3298. ; 28:4, s. 223-230
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Tidskriftsartikel (refereegranskat)abstract
- The release of amines from the ion-exchange groups in DEAE Sepharose® Fast Flow has been studied under static and column conditions. The leakage compounds have been identified and quantified by gas chromatography—mass spectrometry. It was shown that the main leakage product under acidic (pH 1) and basic conditions (pH 14) was N,N,N′,N′-tetraethylethylenediamine. Three other amines were also identified, namely N,N,N′-triethylethylenediamine, diethylaminoethanol and diethylamine. The leakage of amines from DEAE Sepharose Fast Flow treated at pH 1 or 14 for 672 h at 40°C corresponds to a reduction of only 1% of the total ion-exchange capacity.The functional stability of DEAE Sepharose Fast Flow was also studied by separation of a protein mixture during repeated cleaning-in-place treatments with 0·10 m HCl or 1·0 m NaOH. The separation behaviour was unaltered after the gel had been treated for a total contact time of 672 h with 0·10 m HCl or 1·0 m NaOH.The clearance of ethanol from a DEAE Sepharose Fast Flow column stored in a 20% ethanol aqueous solution was also studied.
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| 6. |
- Johansson, Rolf, et al.
(författare)
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Discrimination between Patients with Acoustic Neuroma and with Peripheral Vestibular Lesion by Human Posture Dynamics
- 1994
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 114:3, s. 479-483
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Tidskriftsartikel (refereegranskat)abstract
- A group of normal subjects (n = 17) was compared with two groups of patients, either with vestibular neuritis (n = 18) or with acoustic neuroma (n = 35) by means of posturography when stance was perturbed with vibrators attached to the calf muscles. Dynamic control of human posture was quantified by means of system identification, and the characteristic parameters of swiftness, stiffness, and damping of a transfer function from vibration to force platform response were used for further comparison. Fisher linear discriminant analysis was used to distinguish sets of parameters characteristic of each disease. Hence it was possible to distinguish the vestibular neuritis group both from the normal group (p < 0.01), and from the patients with acoustic neuroma (p < 0.001). The normal group was characterized by a different postural performance, with higher swiftness and stability parameters (stiffness, damping) than those of the patient groups. These findings indicate that there are differences in the dynamic control of posture between the two patient categories, which may require the development of differentiated rehabilitation programs.
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| 7. |
- Karlberg, Mikael, et al.
(författare)
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Effects of Restrained Cervical Mobility on Voluntary Eye Movements and Postural Control
- 1991
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 111:3, s. 664-670
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Tidskriftsartikel (refereegranskat)abstract
- The effects of restrained cervical mobility on pursuit eye movements (PEMS), voluntary saccades and postural control, as measured by posturography, were studied in 11 healthy subjects whose cervical spine movement had been restrained for 5 days by means of a rigid neck-collar. At day 5 mean peak velocity of voluntary saccades at amplitudes of 40 degrees and 60 degrees was significantly reduced, as was mean peak gain of PEMs at a stimulus velocity of 50 degrees/s; the variance of body position in vibration-induced body sway was significantly increased, but there was no difference in variance of galvanically-induced body sway or in velocity of vibration-induced body sway. The results suggest that restriction of cervical movements per se affects voluntary eye movements, a conclusion also consistent with findings in patients with tension headache. Restriction of cervical movement only marginally affects postural control.
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| 10. |
- Lundqvist, Helen, et al.
(författare)
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Neutrophil control of formylmethionyl-leucyl-phenylalanine induced mobilization of secretory vesicles and NADPH-oxidase activation: Effect of an association of the ligand-receptor complex to the cytoskeleton
- 1994
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Ingår i: Biochimica et Biophysica Acta. Molecular Cell Research. - : Elsevier. - 0167-4889 .- 1879-2596. ; 1224:1, s. 43-50
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Tidskriftsartikel (refereegranskat)abstract
- The stimulus formylmethionyl-leucyl-phenylalanine (FMLP) interacts with neutrophils and generates signal(s) in the cells that induces mobilization of the secretory vesicles as well as activation of the superoxide anion/hydrogen peroxide generating NADPH-oxidase. Binding, at 15°C, of FMLP to its neutrophil surface receptor is followed by an association of the ligand-receptor complex to the cell cytoskeleton, and this association occurs concomitant with a desensitization of the cells with respect to activation of the NADPH-oxidase. Other stimuli can still activate the oxidase (in fact even induce a primed response), indicating that the observed phenomenon is stimulus specific and could not be accounted for by an effect on the oxidase itself, but rather that the association of the ligand-receptor complex to the cytoskeleton eliminates the capacity of the complex to generate the signal(s) that activates the NADPH-oxidase. The cytoskeleton associated ligand-receptor complex generates, however, the signal(s) responsible for mobilization of the secretory vesicles, to the plasma membrane, and this mobilization occurs without any increase in the intracellular concentration of free Ca2+.
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