| 1. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 2. |
- Sahlin, Nils-Eric, et al.
(författare)
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Egenansvar och ansvarsprinciper
- 2010
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Ingår i: Eget ansvar i vården Lund 2010. ; , s. 61-67
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Bokkapitel (refereegranskat)
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| 3. |
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| 4. |
- Buckley, Patrick G, et al.
(författare)
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A full-coverage, high-resolution human chromosome 22 genomic microarrayfor clinical and research applications
- 2002
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 11:25, s. 3221-3229
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Tidskriftsartikel (refereegranskat)abstract
- We have constructed the first comprehensive microarray representing a human chromosome for analysis of DNA copy number variation. This chromosome 22 array covers 34.7 Mb, representing 1.1% of the genome, with an average resolution of 75 kb. To demonstrate the utility of the array, we have applied it to profile acral melanoma, dermatofibrosarcoma, DiGeorge syndrome and neurofibromatosis 2. We accurately diagnosed homozygous/heterozygous deletions, amplifications/gains, IGLV/IGLC locus instability, and breakpoints of an imbalanced translocation. We further identified the 14-3-3 eta isoform as a candidate tumor suppressor in glioblastoma. Two significant methodological advances in array construction were also developed and validated. These include a strictly sequence defined, repeat-free, and non-redundant strategy for array preparation. This approach allows an increase in array resolution and analysis of any locus; disregarding common repeats, genomic clone availability and sequence redundancy. In addition, we report that the application of phi29 DNA polymerase is advantageous in microarray preparation. A broad spectrum of issues in medical research and diagnostics can be approached using the array. This well annotated and gene-rich autosome contains numerous uncharacterized disease genes. It is therefore crucial to associate these genes to specific 22q-related conditions and this array will be instrumental towards this goal. Furthermore, comprehensive epigenetic profiling of 22q-located genes and high-resolution analysis of replication timing across the entire chromosome can be studied using our array.
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| 5. |
- Diaz-Parejo, P, et al.
(författare)
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Cerebral energy metabolism during transient hyperglycemia in patients with severe brain trauma
- 2003
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Ingår i: Intensive Care Medicine. - : Springer Science and Business Media LLC. - 0342-4642 .- 1432-1238. ; 29:4, s. 544-550
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To study whether transient hyperglycemia adversely affects cerebral energy metabolism in patients with severe traumatic brain lesions. Design and setting: Prospective, nonrandomized study in the neurosurgical intensive care unit of a university hospital. Patients: 108 patients treated for severe traumatic brain lesions. Interventions: All patients were treated according to neurosurgical intensive care routine including monitoring of, intracranial pressure. One microdialysis catheter was inserted via a burr hole frontally to that used for the intraventricular catheter ("better" position). In patients with focal lesions one or more catheters were inserted into cerebral cortex surrounding an evacuated focal contusion or underlying an evacuated hematoma ("worse" position). Perfusion rate was 0.3 mul/min and samples were taken every. 30 or 60 min. The levels of glucose, pyruvate, lactate, glutamate, and glycerol were analyzed and displayed bedside. Measurements and results: There were 18 episodes of moderate (12-15 mmol/1) and 6 episodes of pronounced (>15 mmol/1) hyperglycemia. Moderate hyperglycemia did not change intracerebral levels of lactate, pyruvate, glutamate, glycerol, or lactate/pyruvate ratio. Lactate concentrations increased during pronounced hyperglycemia. Pronounced cerebral lactic acidosis and a moderate increase in interstitial glycerol concentration indicating cell membrane degradation was observed in a single patient with pronounced, long-lasting hyperglycemia. Conclusions: Cerebral energy metabolism was affected by transient hyperglycemia only at blood glucose concentration above 15 mmol/l as shown by a moderate increase in interstitial lactate level.
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| 6. |
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| 7. |
- Ehlers, Sarah, et al.
(författare)
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Assessing Error Correlations in Remote Sensing-Based Estimates of Forest Attributes for Improved Composite Estimation
- 2018
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Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Today, non-expensive remote sensing (RS) data from different sensors and platforms can be obtained at short intervals and be used for assessing several kinds of forest characteristics at the level of plots, stands and landscapes. Methods such as composite estimation and data assimilation can be used for combining the different sources of information to obtain up-to-date and precise estimates of the characteristics of interest. In composite estimation a standard procedure is to assign weights to the different individual estimates inversely proportional to their variance. However, in case the estimates are correlated, the correlations must be considered in assigning weights or otherwise a composite estimator may be inefficient and its variance be underestimated. In this study we assessed the correlation of plot level estimates of forest characteristics from different RS datasets, between assessments using the same type of sensor as well as across different sensors. The RS data evaluated were SPOT-5 multispectral data, 3D airborne laser scanning data, and TanDEM-X interferometric radar data. Studies were made for plot level mean diameter, mean height, and growing stock volume. All data were acquired from a test site dominated by coniferous forest in southern Sweden. We found that the correlation between plot level estimates based on the same type of RS data were positive and strong, whereas the correlations between estimates using different sources of RS data were not as strong, and weaker for mean height than for mean diameter and volume. The implications of such correlations in composite estimation are demonstrated and it is discussed how correlations may affect results from data assimilation procedures.
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| 8. |
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| 9. |
- Karlmats, Ulf, et al.
(författare)
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Björk på åkermark : - beståndsetablering eller betesbeskogning
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I ett bestånd med björk, planterad 1990 på nedlagd åkermark i 3x1 m förband har en jämförande studie gjorts. Halva arealen har traditionell skogsproduktion, vilken jämförts med en del med skötsel för kombinerad betesdrift och skogsproduktion. I arbetet redovisas utnyttjad metodik vid anläggning, markbehandling, ogräsbekämpning, stängsling och djurhållning, röjning och gallring, nuvarande och beräknad total produktion, grenrensning samt skador. Tre viktiga regler som har bidragit till den lyckosamma etableringen vid beskogningen av denna betesmark är kontinuerlig ogräsbekämpning, tidig och kraftfull röjning/gallring samt stängsling. In a birch stand established in 1990 on former agricultural land in a 3x1 m spacing a comparative study was made. Half the accerage has ad a traditional silviculture while the other half has been managed aiming at future grace land combined with wood production. In this paper we describe the establishment method used, soil treatment, weed protection, fencing and animal treatment, thinning, productivity and yield, furthermore pruning and occurrence of damages. Three important rules for establishment of silvipastures are continuous weed elimination, early, forceful thinning and good fencing.
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| 10. |
- Lindgren, Nils, et al.
(författare)
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Data assimilation in stand level forest inventory – first results
- 2015
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Ingår i: Natural resources and bioeconomy studies. - 2342-7639. ; 29, s. 37-37
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Data assimilation in stand-level forest inventory – first results Nils Lindgren 1 , Mattias Nyström1 , Jörgen Wallerman 1 , Sarah Ehlers 1 , Anton Grafström1 , Anders Muszta 1 , Kenneth Nyström1 , Erik Willen 2 , Johan Fransson 1 , Jonas Bohlin 1 , Håkan Olsson 1 , Göran Ståhl 1 1Swedish University of Agricultural Sciences, Umeå, Sweden 2Skogforsk, Uppsala, Sweden As we are entering an era of increased supply of remote sensing data, we believe that data assimilation has a large potential for keeping forest stand registers up to date (Ehlers et al. 2013). Data assimilation combines forecasts of previous estimates with new observations of the current state in an optimal way based on the uncertainties in the forecast and the observations. These forecasting and updating steps can be repeated with new available observations to get improved estimations. In the present study, we use canopy height models obtained from matching of digital aerial photos over the test site Remningstorp in Sweden, acquired 2003, 2005, 2007, 2009, 2010 and 2012 and normalized with a DEM from airborne laser scanning. Stem volume was estimated for each data acquisition and stand, using regression functions based on field reference data from sample plots. Forecasting was done with growth functions constructed from National Forest Inventory plots. The remote sensing estimates for each time point were assimilated with the forecasts of the previous estimates, using extended Kalman filtering. Validation was done on 40 m radius sample plots dominated by Norway spruce. Early results for three stands show that the variances were lower when using assimilation of new estimates and there was less fluctuation compared to repeated remote sensing estimates. The results for the assimilated data at year 2011 were also consistently closer to the validation data measured in 2011 compared to the remote sensing estimates from year 2011.
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| 11. |
- Lindgren, Nils, et al.
(författare)
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Data Assimilation of Growing Stock Volume Using a Sequence of Remote Sensing Data from Different Sensors
- 2022
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Ingår i: Canadian Journal of Remote Sensing. - : Informa UK Limited. - 0703-8992 .- 1712-7971. ; 48, s. 127-143
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Tidskriftsartikel (refereegranskat)abstract
- Airborne Laser Scanning (ALS) has implied a disruptive transformation of how data are gathered for forest management planning in Nordic countries. We show in this study that the accuracy of ALS predictions of growing stock volume can be maintained and even improved over time if they are forecasted and assimilated with more frequent but less accurate remote sensing data sources like satellite images, digital photogrammetry, and InSAR. We obtained these results by introducing important methodological adaptations to data assimilation compared to previous forestry studies in Sweden. On a test site in the southwest of Sweden (58 degrees 27 ' N, 13 degrees 39 ' E), we evaluated the performance of the extended Kalman filter and a proposed modified filter that accounts for error correlations. We also applied classical calibration to the remote sensing predictions. We evaluated the developed methods using a dataset with nine different acquisitions of remotely sensed data from a mix of sensors over four years, starting and ending with ALS-based predictions of growing stock volume. The results showed that the modified filter and the calibrated predictions performed better than the standard extended Kalman filter and that at the endpoint the prediction based on data assimilation implied an improved accuracy (25.0% RMSE), compared to a new ALS-based prediction (27.5% RMSE).
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| 12. |
- Lindgren, Nils, et al.
(författare)
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Importance of Calibration for Improving the Efficiency of Data Assimilation for Predicting Forest Characteristics
- 2022
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Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Data assimilation (DA) is often used for merging observations to improve the predictions of the current and future states of characteristics of interest. In forest inventory, DA has so far found limited use, although dense time series of remotely sensed (RS) data have become available for estimating forest characteristics. A problem in forest inventory applications based on RS data is that errors from subsequent predictions tend to be strongly correlated, which limits the efficiency of DA. One reason for such a correlation is that model-based predictions, using techniques such as parametric or non-parametric regression, are normally biased conditional on the actual ground conditions, although they are unbiased conditional on the RS predictor variables. A typical case is that predictions are shifted towards the mean, i.e., small true values are overestimated, and large true values are underestimated. In this study, we evaluated if the classical calibration of RS-based predictions could remove this type of bias and improve DA results. Through a simulation study, we mimicked growing stock volume predictions from two different sensors: one from a metric strongly correlated with growing stock volume, mimicking airborne laser scanning, and one from a metric slightly less correlated with growing stock volume, mimicking data obtained from 3D digital photogrammetry. Consistent with previous findings, in areas such as chemistry, we found that classical calibration made the predictions approximately unbiased. Further, in most cases, calibration improved the DA results, evaluated in terms of the root mean square error of predicted volumes, evaluated at the end of a series of ten RS-based predictions.
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| 13. |
- Lindgren, Nils, et al.
(författare)
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Improved Prediction of Forest Variables Using Data Assimilation of Interferometric Synthetic Aperture Radar Data
- 2017
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Ingår i: Canadian Journal of Remote Sensing. - : Informa UK Limited. - 0703-8992 .- 1712-7971. ; 43, s. 374-383
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Tidskriftsartikel (refereegranskat)abstract
- The statistical framework of data assimilation provides methods for utilizing new data for obtaining up-to-date forest data: existing forest data are forecasted and combined with each new remote sensing data set. This new paradigm for updating forest database, well known from other fields of study, will provide a framework for utilizing all available remote sensing data in proportion to their quality to improve prediction. It also solves the problem that not all remote sensing data sets provide information for the entire area of interest, since areas with no remote sensing data can be forecasted until new remote sensing data become available. In this study, extended Kalman filtering was used for assimilating data from 19 TanDEM-X InSAR images on 137 sample plots, each of 10-meter radius at a test site in southern Sweden over a period of 4 years. At almost all time points data assimilation resulted in predictions closer to the reference value than predictions based on data from that single time point. For the study variables Lorey's mean height, basal area, and stem volume, the median reduction in root mean square error was 0.4 m, 0.9 m(2)/ha, and 15.3 m(3)/ha (2, 3, and 6 percentage points), respectively.
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| 14. |
- Nielsen, T. H., et al.
(författare)
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Bedside Diagnosis of Mitochondrial Dysfunction After Malignant Middle Cerebral Artery Infarction
- 2014
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Ingår i: Neurocritical Care. - : Springer Science and Business Media LLC. - 1541-6933 .- 1556-0961. ; 21:1, s. 35-42
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Tidskriftsartikel (refereegranskat)abstract
- The study explores whether the cerebral biochemical pattern in patients treated with hemicraniectomy after large middle cerebral artery infarcts reflects ongoing ischemia or non-ischemic mitochondrial dysfunction. The study includes 44 patients treated with decompressive hemicraniectomy (DCH) due to malignant middle cerebral artery infarctions. Chemical variables related to energy metabolism obtained by microdialysis were analyzed in the infarcted tissue and in the contralateral hemisphere from the time of DCH until 96 h after DCH. Reperfusion of the infarcted tissue was documented in a previous report. Cerebral lactate/pyruvate ratio (L/P) and lactate were significantly elevated in the infarcted tissue compared to the non-infarcted hemisphere (p < 0.05). From 12 to 96 h after DCH the pyruvate level was significantly higher in the infarcted tissue than in the non-infarcted hemisphere (p < 0.05). After a prolonged period of ischemia and subsequent reperfusion, cerebral tissue shows signs of protracted mitochondrial dysfunction, characterized by a marked increase in cerebral lactate level with a normal or increased cerebral pyruvate level resulting in an increased LP-ratio. This biochemical pattern contrasts to cerebral ischemia, which is characterized by a marked decrease in cerebral pyruvate. The study supports the hypothesis that it is possible to diagnose cerebral mitochondrial dysfunction and to separate it from cerebral ischemia by microdialysis and bed-side biochemical analysis.
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| 15. |
- Nielsen, T. H., et al.
(författare)
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Recirculation usually precedes malignant edema in middle cerebral artery infarcts
- 2012
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Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 1600-0404 .- 0001-6314. ; 126:6, s. 404-410
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Tidskriftsartikel (refereegranskat)abstract
- Objectives - In patients with large middle cerebral artery (MCA) infarcts, maximum brain swelling leading to cerebral herniation and death usually occurs 25 days after onset of stroke. The study aimed at exploring the pattern of compounds related to cerebral energy metabolism in infarcted brain tissue. Methods - Forty-four patients with malignant MCA infarcts were included after decision to perform decompressive hemicraniectomy (DHC). Cerebral energy metabolism was in all patients monitored bedside by 13 microdialysis catheters inserted into the infarcted hemisphere during DHC. In 29 of the patients, one microdialysis catheter was also placed in the non-infarcted hemisphere. MCA blood-flow velocity was monitored bilaterally by transcranial Doppler ultrasound. Results - The interstitial glucose levels were in both sides within normal limits throughout the monitoring period. Mean lactate/pyruvate (LP) ratio was very high in infarcted tissue immediately after DHC. The ratio slowly decreased but did not reach normal level during the study period. In the infarcted hemisphere, MCA blood-flow velocities increased from approximately 42 cm/s 1 day prior to DHC (nine of nine patients) to approximately 60 cm/s at day 4. Conclusions - Normal interstitial glucose level in the infarcted hemisphere in combination with substantial MCA blood-flow velocities bilaterally even before DHC was performed indicates that malignant brain swelling usually commences when the embolus/thrombosis has been largely resolved and recirculation of the infarcted area has started. The protracted increase of the LP ratio in infarcted tissue might indicate mitochondrial dysfunction.
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| 16. |
- Nittby, Henrietta Redebrandt, et al.
(författare)
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Early postoperative haematomas in neurosurgery
- 2016
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 158:5, s. 837-846
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Tidskriftsartikel (refereegranskat)abstract
- Background: A postoperative haematoma can be a very serious complication following a neurosurgical procedure. Patients should be informed about the risks of such an event prior to surgery. From a practical point of view, it would be important to know when the patient is most likely to deteriorate and to require surgery because of a postoperative haematoma and when it might be safe to transfer the patient to the regular ward. The up-to-date studies regarding this topic are few. Methods: We therefore undertook the present retrospective study, including a cohort of all patients operated on at the Department of Neurosurgery in Lund during the years 2011–2014, with the aim to define the time windows for clinical deterioration and reoperation, and whether risk factors such as anticoagulant agents/antiplatelet therapy, emergency versus elective surgery and abnormal coagulation blood values were present. We also defined the type of surgery resulting in postoperative haematoma and tried to find the clinical state of the patients when they deteriorated, as well as the outcome at 3 months postoperatively. Results: During the time period from June 2011 to November 2014, a total of 7,055 surgical procedures of all kinds were registered at our department. By the search for the diagnosis codes AWE00 and AWD00 (reoperation for deep haemorrhage and for superficial haemorrhage respectively), we identified 93 reoperations, meaning a percentage of 1.3 %. Thirty-four of the reoperations were done within the first 24 h. Twenty-four patients were reoperated on >24 h but ≤72 h after the first operation. Only four patients who were initially doing well postoperatively showed a delayed clinical deterioration within the time frame from >6 h and ≤24 h postoperatively. This means that 0.06 % of the patients who were operated upon were doing well initially, being completely awake and with no new neurological deficit and no deterioration within the first 6 h postoperatively, and then deteriorated from a postoperative haematoma within the time frame of >6 h and ≤24 h postoperatively. Conclusions: We could conclude that no exact time window distinguished very early from somewhat later postoperative haematomas in our material. However, all but two patients deteriorating between 6 and 24 h after the operation had at least one of the following risk factors defined for post-operative haematoma: meningioma surgery, anticoagulant agents/antiplatelet therapy prior to surgery (including Dalteparin [Fragmin®], Enoxaparinnatrium [Klexane®], Warfarin [Waran®], ASA [Trombyl®] or ASA and caffeine [Treo®]), emergency operation, posterior fossa surgery or chronic subdural haematoma in a patient with a shunt. This material is too small to make any definitive conclusions, but a suggestion could be to include these factors when considering the transfer of a patient from the postoperative intensive care unit to the regular ward.
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| 17. |
- Nyström, Mattias, et al.
(författare)
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Assimilating remote sensing data with forest growth models
- 2015
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Konferensbidrag (refereegranskat)abstract
- As we are entering an era of increased supply of remote sensing data, we believe that dataassimilation that combines growth forecasts of previous estimates with new observations of thecurrent state has a large potential for keeping forest stand registers up to date (Ehlers et al. 2013).The data assimilation will update a forest model e in an optimal way based on the uncertainties inthe forecast and the observations, each time new data becomes available. These forecasting andupdating steps can be repeated with new available observations to get improved estimations. In thisstudy we present the first practical results from data assimilation of mean tree height, basal area andgrowing stock. The remote sensing data used were canopy height models obtained from matching ofdigital aerial photos over the test site Remningstorp in Sweden. The photos were acquired 2003,2005, 2007, 2009, 2010 and 2012 and normalized with a DEM from airborne laser scanning.The procedure for the data assimilation was as follows: mean tree height, basal area and growingstock were predicted on 18 m × 18 m raster cells using the area based method. Ten meter radiussample plots were used as field calibration data. For each photo year, the field data were adjustedfor growth to have the same state year as each acquisition year of the photos. Growth models wereconstructed from National Forest Inventory plot data. Data assimilation could then be performed onraster cell level by initially start with the estimates from 2003 year´s photos. This prediction was thenforecasted to year 2005 by calculating the growth for the raster cell. This forecasted value is thenblended with the new remote sensing estimation collected 2005. The process was then repeated forthe following years where new measurements were available. In this study, extended Kalmanfiltering was used to blend the forecasted values with the new remote sensing measurements.Validation was done for 40 m radius field plots. Further, the results were also compared with twoalternative approaches: the first was to forecast the first remote sensing estimate to the endpointand the second was to use remote sensing data acquired at the endpoint only.The preliminary results for the eight forest stands show that the variances were lower when usingassimilation of new estimates and there were less fluctuation compared to only using remote sensingdata from the endpoint. However, the mean deviation from the measured value 2011 was lowerwhen only data from the endpoint were used. The assimilated values 2011 were consistently closerto the validation data compared to only forecasting the starting estimate from 2003 to 2011.
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| 18. |
- Nyström, Mattias, et al.
(författare)
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Data assimilation : a prototype system to assimilate forest stand information
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this report is to describe a data assimilation prototype program(Appendix A) developed to estimate forest stand data. The program was developed and tested on data col-lected on the forest estate Remningstorp in southern Sweden. Data assimilation can be used to sequentially combine remote sensing based estimates of forest variables with predictions from growth models. The assimilation routine implemented was the extended Kalman Filter. The program supports two different ways to assimilate the forest data: (1) pixel-wise and (2)stand-wise. In the pixel-wise way, raster cells are used as assimilation unit and can beaggregated to a stand for evaluation. In the stand-wise way, the whole stand is assimilatedas one unit. The two methods has pros and cons. The pixel-wise way is simple to use as nostand-delineation is needed, but might be subject to boundary effects and noise due to geo-metric errors. Using the developed code, it has been shown in three case studies that thecombination of time series of remote sensing data and forest growth functions provides bet-ter estimates of forest variables than only using forecasting, or only using the latest remotesensing data. This opens up for a new way to keep forest stand registers up to date.
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| 19. |
- Nyström, Mattias, et al.
(författare)
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Data assimilation in forest inventory: first empirical results
- 2015
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 6, s. 4540-4557
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Tidskriftsartikel (refereegranskat)abstract
- Data assimilation techniques were used to estimate forest stand data in 2011 bysequentially combining remote sensing based estimates of forest variables with predictions fromgrowth models. Estimates of stand data, based on canopy height models obtained from imagematching of digital aerial images at six different time-points between 2003 and 2011, served asinput to the data assimilation. The assimilation routines were built on the extended Kalman filter.The study was conducted in hemi-boreal forest at the Remningstorp test site in southern Sweden(lat. 13˝371 N; long. 58˝281 E). The assimilation results were compared with two other methodsused in practice for estimation of forest variables: the first was to use only the most recent estimateobtained from remotely sensed data (2011) and the second was to forecast the first estimate (2003)to the endpoint (2011). All three approaches were validated using nine 40 m radius validation plots,which were carefully measured in the field. The results showed that the data assimilation approachprovided better results than the two alternative methods. Data assimilation of remote sensing timeseries has been used previously for calibrating forest ecosystem models, but, to our knowledge,this is the first study with real data where data assimilation has been used for estimating forestinventory data. The study constitutes a starting point for the development of a framework usefulfor sequentially utilizing all types of remote sensing data in order to provide precise and up-to-dateestimates of forest stand parameters.
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| 20. |
- Nyström, Mattias, et al.
(författare)
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Data assimilation in forest inventory, first empirical results using ALS data
- 2015
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Konferensbidrag (refereegranskat)abstract
- A first data assimilation case study using a time series of ALS for updating forest stand data is presented. Forest stand data are predicted from each ALS acquisition. Kalman filtering and growth models are then used to combine each new ALS based prediction with forecasts from the previous data acquisition.
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| 21. |
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| 22. |
- Reinstrup, Peter, et al.
(författare)
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Intracerebral microdialysis in clinical practice: baseline values for chemical markers during wakefulness, anesthesia, and neurosurgery
- 2000
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Ingår i: Neurosurgery. - : Ovid Technologies (Wolters Kluwer Health). - 0148-396X .- 1524-4040. ; 47:3, s. 701-710
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The study was undertaken to measure baseline values for chemical markers in human subjects during wakefulness, anesthesia, and neurosurgery, using intracerebral microdialysis. METHODS: Microdialysis catheters were inserted into normal posterior frontal cerebral cortex in nine patients who were undergoing surgery to treat benign lesions of the posterior fossa. The perfusion rate was 1.0 microl/min during anesthesia/neurosurgery and the early postoperative course and 0.3 microl/min during the later course. Bedside biochemical analyses of glucose, pyruvate, lactate, glycerol, glutamate, and urea were performed before, during, and after neurosurgery. After the bedside analyses, all samples were frozen for subsequent high-performance liquid chromatographic analyses of amino acids. RESULTS: The following baseline values were obtained during wakefulness (perfusion rate, 0.3 microl/min): glucose, 1.7+/-0.9 mmol/L; lactate, 2.9+/-0.9 mmol/L; pyruvate, 166+/-47 micromol/L; lactate/pyruvate ratio, 23+/-4; glycerol, 82+/-44 micromol/L; glutamate, 16+/-16 mmol/L; urea, 4.4+/-1.7 mmol/L. Marked increases in the levels of all chemical markers were observed at the beginning and end of anesthesia/surgery. CONCLUSION: The study provides human baseline levels for biochemical markers that can presently be measured at the bedside during neurointensive care. In addition, some changes that occurred under varying physiological conditions are described.
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| 23. |
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| 24. |
- Saha, Atal, et al.
(författare)
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Whole-genome resequencing confirms reproductive isolation between sympatric demes of brown trout (Salmo trutta) detected with allozymes
- 2022
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:2, s. 498-511
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Tidskriftsartikel (refereegranskat)abstract
- The sympatric existence of genetically distinguishable populations of the same species remains a puzzle in ecology. Coexisting salmonid fish populations are known from over 100 freshwater lakes. Most studies of sympatric populations have used limited numbers of genetic markers making it unclear if genetic divergence involves certain parts of the genome. We returned to the first reported case of salmonid sympatry, initially detected through contrasting homozygosity at a single allozyme locus (coding for lactate dehydrogenase A) in brown trout in the small Lakes Bunnersjöarna, Sweden. First, we verified the existence of the two coexisting demes using a 96-SNP fluidigm array. We then applied whole-genome resequencing of pooled DNA to explore genome-wide diversity within and between these demes; nucleotide diversity was higher in deme I than in deme II. Strong genetic divergence is observed with genome-wide FST ≈ 0.2. Compared with data from populations of similar small lakes, this divergence is of similar magnitude as that between reproductively isolated populations. Individual whole-genome resequencing of two individuals per deme suggests higher inbreeding in deme II versus deme I, indicating different degree of isolation. We located two gene-copies for LDH-A and found divergence between demes in a regulatory section of one of these genes. However, we did not find a perfect fit between the sequence data and previous allozyme results, and this will require further research. Our data demonstrates genome-wide divergence governed mostly by genetic drift but also by diversifying selection in coexisting populations. This type of hidden biodiversity needs consideration in conservation management.
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| 25. |
- Sahlin, Nils-Eric, et al.
(författare)
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Etiska aspekter på nanomedicin
- 2011
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Ingår i: Symposiet forskningens etiska gränser Lund 18 maj 2010. - 9789163360374 ; , s. 108-117
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 26. |
- Sandén, Emma, et al.
(författare)
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Aberrant immunostaining pattern of the CD24 glycoprotein in clinical samples and experimental models of pediatric medulloblastomas
- 2015
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Ingår i: Journal of Neuro-Oncology. - : Springer Science and Business Media LLC. - 0167-594X .- 1573-7373. ; 123:1, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- The CD24 glycoprotein is a mediator of neuronal proliferation, differentiation and immune suppression in the normal CNS, and a proposed cancer biomarker in multiple peripheral tumor types. We performed a comparative analysis of CD24 gene expression in a large cohort of pediatric and adult brain tumors (n = 813), and further characterized protein expression in tissue sections (n = 39), primary brain tumor cultures (n = 12) and a novel orthotopic group 3 medulloblastoma xenograft model. Increased CD24 gene expression was demonstrated in ependymomas, medulloblastomas, anaplastic astrocytomas and glioblastomas, although medulloblastomas displayed higher expression than all other tumor entities. Preferential expression of CD24 in medulloblastomas was confirmed at protein level by immunostaining and computerized image analysis of cryosections. Morphologies and immunophenotyping of CD24(+) cells in tissue sections tentatively suggested disparate functions in different tumor subsets. Notably, protein staining of medulloblastoma cells was associated with prominent cytoplasmic and membranous granules, enabling rapid and robust identification of medulloblastoma cells in clinical tissue samples, as well as in experimental model systems. In conclusion, our results implicate CD24 as a clinically and experimentally useful medulloblastoma immunomarker. Although our results encourage further functional studies of CD24 as a potential molecular target in subsets of brain tumors, the promiscuous expression of CD24 in vivo highlights the importance of specificity in the future design of such targeted treatment.
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| 27. |
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| 28. |
- Ståhl, Nils
(författare)
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Bedside monitoring of cerebral energy metabolism using intracerebral microdialysis during neuro intensive care
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In clinical situations with raised intracranial pressure (ICP) and impending insufficient cerebral blood flow (ischaemia), bedside information about energy metabolism in the brain would be helpful. Microdialysis is a technique that makes it possible to monitor the interstitial concentrations of various compounds in an organ. Intracerebral microdialysis with bedside analysis of metabolites related to energy metabolism might therefore be a valuable tool to elucidate important aspects on biochemical events during neuro intensive care and ultimately a tool for supervision of the neurologically critically ill patient. In order to estimate the consequences for cerebral energy metabolism during a controlled reduction of cerebral perfusion pressure as in the “Lund concept”, we have used clinical intracerebral microdialysis with multiple catheters as a routine in patients with severe head injuries. Baseline levels for different metabolites under physiological conditions are provided. Changes of cerebral energy metabolism in different parts of the brain during an intractable increase of ICP are described. Treatment according to the “Lund concept” does not interfere with cerebral energy metabolism. A ”biochemical penumbra zone” with increased vulnerability to secondary insults surrounds focal traumatic lesions. Transient hyperglycaemia (<15 mmol/L) does not affect cerebral energy metabolism if oxygen delivery is sufficient. Intracerebral microdialysis with bedside biochemical analyses can be performed as a routine procedure during neuro intensive care. The technique is useful both for analysing groups of patients and for supervision of the individual patient in the neuro intensive care.
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| 29. |
- Ståhl, Nils, et al.
(författare)
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Exploiting high-speed sequences for background subtraction
- 2016
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Ingår i: Proceedings - 3rd IAPR Asian Conference on Pattern Recognition, ACPR 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479961009 ; , s. 106-110
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Konferensbidrag (refereegranskat)abstract
- Observing the world in high speed can give rise to systems for e.g., tracking with super-human capabilities or extremely low latency human-computer interaction. However, the demand on computational power grows with the increased framerate, limiting the usefulness of such systems. In this paper we propose a background subtraction method aimed at high-speed video which enables higher level algorithms to focus on the interesting regions in the image. We show through experiments on high-speed video that where using conventional background subtraction methods in high-speed videos fail, the proposed method successfully detects the foreground in the image.
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| 30. |
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| 31. |
- Zolfaghari, Shaian, et al.
(författare)
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Burr hole craniostomy versus minicraniotomy in chronic subdural hematoma: a comparative cohort study
- 2021
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 163, s. 3217-3223
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Tidskriftsartikel (refereegranskat)abstract
- Background Chronic subdural hematoma (CSDH) is one of the most common neurosurgical diseases. In surgical management of CSDH, there is a lack of standardized guidelines concerning surgical techniques and a lack of consensus on which technique(s) are optimal. Neurosurgical centers have shown a wide variation in surgical techniques. The purpose of this study was to compare two different surgical techniques, one burr hole craniostomy with an active subgaleal drain (BHC) and minicraniotomy with a passive subdural drain (MC). Methods We conducted a multicenter retrospective cohort study at two neurosurgical centers in Sweden which included patients with unilateral CSDHs that received surgical treatment with either BHC or MC. The primary outcomes in comparison of the techniques were 30-day mortality, recurrence rate, and complications according to the Landriel Ibanez grading system for complications. Results A total of 1003 patients were included in this study. The BHC subgroup included 560 patients, and the MC subgroup included 443 patients. A 30-day mortality when comparing BHC (2.3%) and MC (2.7%) was similar (p = 0.701). Comparing recurrence rate for BHC (8.9%) and MC (10.8%) showed no significant difference (p = 0.336). We found that medical complications were significantly more common in the MC group (p = 0.001). Surgical complications (type IIb) was also associated with the MC group (n = 10, p = 0.003). Out of the 10 patients with type IIb complications in the MC group, 8 had postoperative acute subdural hematomas. Conclusions BHC was comparable to MC concerning 30-day mortality rate and recurrence rates. We did, however, find that MC was significantly associated with medical complications and serious surgical postoperative complications.
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| 32. |
- Zolfaghari, Shaian, et al.
(författare)
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Does time from diagnostic CT until surgical evacuation affect outcome in patients with chronic subdural hematoma?
- 2018
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 160:9, s. 1703-1709
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions. Patients diagnosed with CSDH’s are often planned for subacute surgery. This means that time from diagnostic CT scan until actual surgery might often be prolonged. There are no previous studies that highlight the effect of delayed intervention in this population. Method: Patients that underwent surgical evacuation for a CSDH at Skåne University Hospital between 1 January 2015 and 31 December 2016 were included in this retrospective cohort study (n = 179). The primary aim was to determine if time from initial diagnosis by head-CT until surgical evacuation had a significant effect on outcome. The following was assessed by mortality, re-operation, number of days spent in hospital, discharge to home/institution, and functional outcome assessed by GOS. Secondary aims were to evaluate the effect of NOAC, vitamin K antagonists, and antiplatelet drugs on time from CT to surgery and re-operation frequency. Results: Mean time from diagnostic CT scan until surgery was 76 h. No significant relationship was found between time from CT to surgical evacuation and number of days spent in hospital, discharge to own home/institution, 1-year mortality, or outcome assessed by GOS at discharge from hospital. The clear majority (95.5%) of the patients were GCS ≥ 13 pre-operatively. No correlation could be seen between use of NOAC, vitamin K antagonists, or antiplatelet drugs regarding the risk for reoperation within 6 months, and no correlation between the use of these agents and time from CT to surgery. The 30-day mortality was too low to draw any statistically significant conclusions (n = 4). Conclusion: In this retrospective cohort study, we could conclude that a delay from initial diagnosis confirming a CSDH to surgical evacuation had no negative effect on outcome when surgery was performed within the time frames and on patients with pre-operatively favorable GCS scores (≥ 13) outlined in our study.
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| 33. |
- Zolfaghari, Shaian, et al.
(författare)
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Risk factors for need of reoperation in bilateral chronic subdural haematomas
- 2021
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 163, s. 1849-1856
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Tidskriftsartikel (refereegranskat)abstract
- Background Chronic subdural haematoma (CSDH) is one of the most common neurosurgical diseases. A subtype of CSDH is bilateral chronic subdural haematoma (bCSDH) which represents 20-25% of patients with CSDH and has a higher recurrence rate. There is no clear consensus on how bCSDH should be treated regarding upfront unilateral- or bilateral evacuation of both haematomas. The purpose of this study was to identify risk factors associated with reoperation of bCSDH. Methods A total of 326 patients with radiological evidence of bCSDH were included in this retrospective cohort study where 133 (40.8%) patients underwent primary bilateral evacuation and 193 (59.2%) primary unilateral evacuation. The two centres operated using different surgical approaches. Analyses were performed to identify risk factors associated with reoperation of bCSDH. Reoperation rate was defined as reoperation of CSDH on either side of the hemisphere within 3 months after primary evacuation. Results The cohort had a total reoperation rate of 26.4%. Patients which underwent unilateral evacuation had a reoperation rate of 32.1%, and the bilateral group had a reoperation rate of 18.0% (p=0.005). Multivariable logistic regression identified unilateral evacuation (OR 1.91, p=0.022) and complications according to Ibanez (OR 2.20, p=0.032) to be associated with the need of reoperation of bCSDH. One-burr hole craniostomy with active subgaleal drain was primarily performed in bilateral approach (69.4%) whereas patients operated with minicraniotomy with passive subdural drain were primarily operated by unilateral evacuation of the larger symptomatic side (92.8%). Conclusions Unilateral evacuation of bCSDH was associated with a higher risk for reoperation than upfront bilateral evacuations in this study. There is a need to further discuss the criteria for uni- or bilateral evacuation since patients are treated differently at different centres.
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