| 1. |
- Ehrsson, HH, et al.
(författare)
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Holding an object: neural activity associated with fingertip force adjustments to external perturbations
- 2007
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Ingår i: Journal of neurophysiology. - : American Physiological Society. - 0022-3077 .- 1522-1598. ; 97:2, s. 1342-1352
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Tidskriftsartikel (refereegranskat)abstract
- When you hold an object, a sudden unexpected perturbation can threaten the stability of your grasp. In such situations grasp stability is maintained by fast reflexive-like grip-force responses triggered by the somatosensory feedback. Here we use functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms involved in the grip-force responses associated with unexpected increases (loading) and decreases (unloading) in the load force. Healthy right-handed subjects held an instrumented object (of mass 200 g) between the tips of right index finger and thumb. At some time during an interval of 8 to 45 s the weight of the object was suddenly increased or decreased by 90 g. We analyzed the transient increases in the fMRI signal that corresponded precisely in time to these grip-force responses. Activity in the left primary motor cortex was associated with the loading response, but not with unloading, suggesting that sensorimotor processing in this area mediates the sensory-triggered reflexive increase in grip force during loading. Both the loading and the unloading events activated the cingulate motor area and the medial cerebellum. We suggest that these regions could participate in the updating of the sensorimotor representations of the fingertip forces. Finally, the supplementary somatosensory area located on the medial wall of the parietal lobe showed an increase in activity only during unloading, indicating that this area is involved in the sensorimotor processing generating the unloading response. Taken together, our findings suggest different central mechanisms for the grip-force responses during loading and unloading.
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| 2. |
- Pfeiffer, P, et al.
(författare)
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Short-time infusion of oxaliplatin in combination with capecitabine (XELOX30) as second-line therapy in patients with advanced colorectal cancer after failure to irinotecan and 5-fluorouracil
- 2006
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Ingår i: Annals of Oncology. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 17:2, s. 252-258
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Tidskriftsartikel (refereegranskat)abstract
- Background: The efficacy of oxaliplatin combined with capecitabine (XELOX) as second-line therapy in patients with advanced colorectal cancer (ACRC) resistant to irinotecan is not well established. Oxaliplatin induces acute, cold-induced neuropathy in most patients. The incidence is claimed to be infusion rate-dependent and therefore a 2-h infusion is recommended. Patients and methods: For practical and economic reasons, but also for patient's convenience, we performed a phase II study to examine XELOX30 (capecitabine 1000 mg/m2 orally twice daily on days 1-14 and oxaliplatin 130 mg/m2 as a 30 min infusion on day 1) in patients with ACRC resistant to irinotecan. In addition the pharmacokinetics of oxaliplatin was studied. Results: From November 2002 to September 2003, 70 patients with ACRC were treated with XELOX30. Median age was 62 (range 33-74 years) years and median performance status was 1 (range 0-2). The median number of courses was four (range 1-12) and median cumulative dose of oxaliplatin was 530 (range 125-1560) mg/m2. The response rate was 17% (95% CI 10-23), median time to progression (TTP) was 5.4 months (95% CI 4.6-6.4) and median survival 9.5 months (95% CI 8.5-11.2). White blood cell count (WBC) and performance status were significantly correlated to TTP. Neurotoxicity was moderate: grade 1 56%, grade 2 17% and grade 3 6%. Other grade 3 toxicities were nausea/ vomiting 9%, diarrhoea 14% and PPE 8%. The maximum blood concentration and total body clearance of oxaliplatin was higher than previously reported in studies examining 2-h infusions, but the volume of distribution and terminal half-life was in close agreement with previous results. Conclusion: XELOX30 is a very convenient second-line regimen in ACRC with an activity and safety profile similar to other oxaliplatin schedules. © 2005 European Society for Medical Oncology.
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| 3. |
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| 4. |
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| 5. |
- Bremberg, ER, et al.
(författare)
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An evaluation of pharmacist contribution to an oncology ward in a Swedish hospital
- 2006
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Ingår i: Journal of oncology pharmacy practice : official publication of the International Society of Oncology Pharmacy Practitioners. - : SAGE Publications. - 1078-1552. ; 12:2, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- Aim. The aim of this project was to establish the importance of a pharmacist in the health-care team in improving drug use in an oncology ward in the Department of Oncology, Karolinska University Hospital, Stockholm, Sweden. Methods and patients. The pharmacist participated in the medical round in the mornings and worked as a member of the health-care team. Drug-related problems (DRPs) were identified by drug chart reviews based on data from medical files, laboratory tests and interviews with patients and/or relatives. A questionnaire to physicians and nurses was used to evaluate their experiences of the pharmacist’s contribution to the oncology ward. Results. In total, 114 DRPs were identified in 58 patients. For each DRP, the pharmacist gave proposals for solutions. Sixty-eight suggestions out of 114 (59.6%) were implemented by the physician. Two suggestions (1.8%) were partly followed. For 32 suggestions (28.0%) it was unclear if they had caused any change in medication. Twelve suggestions (10.5%) were not followed. Most of the physicians and nurses acknowledged the pharmacist’s contribution to improved drug use in the ward. Conclusion. A pharmacist can improve drug use in an oncology ward as a member of the health-care team. The pharmacist contributes with a systematic focus on the patient from a drug perspective.
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| 6. |
- Broomand, Amir, et al.
(författare)
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Oxaliplatin neurotoxicity - No general ion channel surface-charge effect
- 2009
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Ingår i: Journal of Negative Results in BioMedicine. - : Springer Science and Business Media LLC. - 1477-5751. ; 8:1, s. 2-
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Tidskriftsartikel (refereegranskat)abstract
- Background. Oxaliplatin is a platinum-based chemotherapeutic drug. Neurotoxicity is the dose-limiting side effect. Previous investigations have reported that acute neurotoxicity could be mediated via voltage-gated ion channels. A possible mechanism for some of the effects is a modification of surface charges around the ion channel, either because of chelation of extracellular Ca2+, or because of binding of a charged biotransformation product of oxaliplatin to the channel. To elucidate the molecular mechanism, we investigated the effects of oxaliplatin and its chloride complex [Pt(dach)oxCl]- on the voltage-gated Shaker K channel expressed in Xenopus oocytes. The recordings were made with the two-electrode and the cut-open oocyte voltage clamp techniques. Conclusion. To our surprise, we did not see any effects on the current amplitudes, on the current time courses, or on the voltage dependence of the Shaker wild-type channel. Oxaliplatin is expected to bind to cysteines. Therefore, we explored if there could be a specific effect on single (E418C) and double-cysteine (R362C/F416C) mutated Shaker channels previously shown to be sensitive to cysteine-specific reagents. Neither of these channels were affected by oxaliplatin. The clear lack of effect on the Shaker K channel suggests that oxaliplatin or its monochloro complex has no general surface-charge effect on the channels, as has been suggested before, but rather a specific effect to the channels previously shown to be affected.
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| 7. |
- Ehrsson, H. Henrik, et al.
(författare)
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Upper limb amputees can be induced to experience a rubber hand as their own
- 2008
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Ingår i: Brain. - : Oxford University Press (OUP). - 1460-2156 .- 0006-8950. ; 131:12, s. 3443-3452
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Tidskriftsartikel (refereegranskat)abstract
- We describe how upper limb amputees can be made to experience a rubber hand as part of their own body. This was accomplished by applying synchronous touches to the stump, which was out of view, and to the index finger of a rubber hand, placed in full view (26 cm medial to the stump). This elicited an illusion of sensing touch on the artificial hand, rather than on the stump and a feeling of ownership of the rubber hand developed. This effect was supported by quantitative subjective reports in the form of questionnaires, behavioural data in the form of misreaching in a pointing task when asked to localize the position of the touch, and physiological evidence obtained by skin conductance responses when threatening the hand prosthesis. Our findings outline a simple method for transferring tactile sensations from the stump to a prosthetic limb by tricking the brain, thereby making an important contribution to the field of neuroprosthetics where a major goal is to develop artificial limbs that feel like a real parts of the body.
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| 8. |
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| 9. |
- Jenmalm, Per, et al.
(författare)
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Lighter or heavier than predicted : neural correlates of corrective mechanisms during erroneously programmed lifts
- 2006
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Ingår i: Journal of Neuroscience. - Bethesda, Md. : Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 26:35, s. 9015-9021
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Tidskriftsartikel (refereegranskat)abstract
- A central concept in neuroscience is that the CNS signals the sensory discrepancy between the predicted and actual sensory consequences of action. It has been proposed that the cerebellum and parietal cortex are involved in this process. A discrepancy will trigger preprogrammed corrective responses and update the engaged sensorimotor memories. Here we use functional magnetic resonance imaging with an event-related design to investigate the neuronal correlates of such discrepancies. Healthy adults repeatedly lifted an object between their right index fingers and thumbs, and on some lifting trials, the weight of the object was unpredictably changed between light (230 g) and heavy (830 g). Regardless of whether the weight was heavier or lighter than predicted, activity was found in the right inferior parietal cortex (supramarginal gyrus). This suggests that this region is involved in the comparison of the predicted and actual sensory input and the updating of the sensorimotor memories. When the object was lighter or heavier than predicted, two different types of preprogrammed force corrections occurred. There was a slow force increase when the weight of the object was heavier than predicted. This corrective response was associated with activity in the left primary motor and somatosensory cortices. The fast termination of the excessive force when the object was lighter than predicted activated the right cerebellum. These findings show how the parietal cortex, cerebellum, and motor cortex are involved in the signaling of the discrepancy between predicated and actual sensory feedback and the associated corrective mechanisms.
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| 10. |
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| 11. |
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| 12. |
- Rosén, Birgitta, et al.
(författare)
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Referral of sensation to an advanced humanoid robotic hand prosthesis.
- 2009
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - : Informa UK Limited. - 1651-2073 .- 0284-4311. ; 43:5, s. 260-266
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Tidskriftsartikel (refereegranskat)abstract
- Hand prostheses that are currently available on the market are used by amputees to only a limited extent, partly because of lack of sensory feedback from the artificial hand. We report a pilot study that showed how amputees can experience a robot-like advanced hand prosthesis as part of their own body. We induced a perceptual illusion by which touch applied to the stump of the arm was experienced from the artificial hand. This illusion was elicited by applying synchronous tactile stimulation to the hidden amputation stump and the robotic hand prosthesis in full view. In five people who had had upper limb amputations this stimulation caused referral touch sensation from the stump to the artificial hand, and the prosthesis was experienced more like a real hand. We also showed that this illusion can work when the amputee controls the movements of the artificial hand by recordings of the arm muscle activity with electromyograms. These observations indicate that the previously described "rubber hand illusion" is also valid for an advanced hand prosthesis, even when it has a robotic-like appearance.
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| 13. |
- Schmitz, Christina, et al.
(författare)
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Brain activity during predictable and unpredictable weight changes when lifting objects.
- 2005
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Ingår i: Journal of Neurophysiology. - : American Physiological Society. - 0022-3077 .- 1522-1598. ; 93:3, s. 1498-509
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Tidskriftsartikel (refereegranskat)abstract
- When humans repetitively lift the same object, the fingertip forces are targeted to the weight of the object. The anticipatory programming of the forces depends on sensorimotor memory representations that provide information on the object weight. In the present study, we investigate the neural substrates of these sensorimotor memory systems by recording the neural activity during predictable or unpredictable changes in the weight of an object in a lifting task. An unpredictable change in weight leads to erroneous programming of the fingertip forces. This triggers corrective mechanisms and an update of the sensorimotor memories. In the present fMRI study, healthy right-handed subjects repetitively lifted an object between right index finger and thumb. In the constant condition, which served as a control, the weight of the object remained constant (either 230 or 830 g). The weight alternated between 230 and 830 g during the regular condition and was irregularly changed between the two weights during the irregular condition. When we contrasted regular minus constant and irregular minus constant, we found activations in the right inferior frontal gyrus pars opercularis (area 44), the left parietal operculum and the right supramarginal gyrus. Furthermore, irregular was associated with stronger activation in the right inferior frontal cortex as compared with regular. Taken together, these results suggest that the updating of sensorimotor memory representations and the corrective reactions that occur when we manipulate different objects correspond to changes in synaptic activity in these fronto-parietal circuits.
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| 14. |
- Ullen, F, et al.
(författare)
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Neural control of rhythmic sequences
- 2005
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923. ; 1060, s. 368-376
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Tidskriftsartikel (refereegranskat)
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| 15. |
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