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Sökning: WFRF:(Martensson Johan)

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1.
  • Engerström, Lars, et al. (författare)
  • Prevalence and impact of early prone position on 30-day mortality in mechanically ventilated patients with COVID-19: a nationwide cohort study
  • 2022
  • Ingår i: Critical Care. - : BMC. - 1364-8535 .- 1466-609X. ; 26:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background COVID-19 ARDS shares features with non-COVID ARDS but also demonstrates distinct physiological differences. Despite a lack of strong evidence, prone positioning has been advocated as a key therapy for COVID-19 ARDS. The effects of prone position in critically ill patients with COVID-19 are not fully understood, nor is the optimal time of initiation defined. In this nationwide cohort study, we aimed to investigate the association between early initiation of prone position and mortality in mechanically ventilated COVID-19 patients with low oxygenation on ICU admission. Methods Using the Swedish Intensive Care Registry (SIR), all Swedish ICU patients >= 18 years of age with COVID-19 admitted between March 2020, and April 2021 were identified. A study-population of patients with PaO2/FiO(2) ratio <= 20 kPa on ICU admission and receiving invasive mechanical ventilation within 24 h from ICU admission was generated. In this study-population, the association between early use of prone position (within 24 h from intubation) and 30-day mortality was estimated using univariate and multivariable logistic regression models. Results The total study cohort included 6350 ICU patients with COVID-19, of whom 46.4% were treated with prone position ventilation. Overall, 30-day mortality was 24.3%. In the study-population of 1714 patients with lower admission oxygenation (PaO2/FiO(2) ratio <= 20 kPa), the utilization of early prone increased from 8.5% in March 2020 to 48.1% in April 2021. The crude 30-day mortality was 27.2% compared to 30.2% in patients not receiving early prone positioning. We found no significant association between early use of prone positioning and survival. Conclusions During the first three waves of the COVID-19 pandemic, almost half of the patients in Sweden were treated with prone position ventilation. We found no association between early use of prone positioning and survival in patients on mechanical ventilation with severe hypoxemia on ICU admission. To fully elucidate the effect and timing of prone position ventilation in critically ill patients with COVID-19 further studies are desirable.
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2.
  • Martensson, Johan, et al. (författare)
  • White matter microstructure predicts foreign language learning in army interpreters
  • 2020
  • Ingår i: Bilingualism. - : Cambridge University Press. - 1366-7289 .- 1469-1841. ; 23:4, s. 763-771
  • Tidskriftsartikel (refereegranskat)abstract
    • Adult foreign language acquisition is challenging, and the degree of success varies among individuals. Anatomical differences in brain structure prior to training can partly explain why some learn more than others. We followed a sample of conscript interpreters undergoing intense language training to study learning-related changes in white-matter microstructure (FA, MD, RD and AD) and associations between differences in brain structure prior to training with acquired language proficiency. No evidence for changes in white matter microstructure relative to a control group was found. Starting values of RD, AD and MD were positively related to final test scores of language proficiency, corroborating earlier findings in the field and highlighting the need for further study of how initial brain structure influences and interacts with learning outcomes.
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3.
  • Albert, Christian, et al. (författare)
  • Neutrophil Gelatinase-Associated Lipocalin Measured on Clinical Laboratory Platforms for the Prediction of Acute Kidney Injury and the Associated Need for Dialysis Therapy : A Systematic Review and Meta-analysis
  • 2020
  • Ingår i: American Journal of Kidney Diseases. - : Elsevier BV. - 0272-6386 .- 1523-6838. ; 76:6, s. 826-
  • Forskningsöversikt (refereegranskat)abstract
    • Rationale & Objective: The usefulness of measures of neutrophil gelatinase-associated lipocalin (NGAL) in urine or plasma obtained on clinical laboratory platforms for predicting acute kidney injury (AKI) and AKI requiring dialysis (AKI-D) has not been fully evaluated. We sought to quantitatively summarize published data to evaluate the value of urinary and plasma NGAL for kidney risk prediction.Study Design: Literature-based meta-analysis and individual-study-data meta-analysis of diagnostic studies following PRISMA-IPD guidelines.Setting & Study Populations: Studies of adults investigating AKI, severe AKI, and AKI-D in the setting of cardiac surgery, intensive care, or emergency department care using either urinary or plasma NGAL measured on clinical laboratory platforms.Selection Criteria for Studies: PubMed, Web of Science, Cochrane Library, Scopus, and congress abstracts ever published through February 2020 reporting diagnostic test studies of NGAL measured on clinical laboratory platforms to predict AKI.Data Extraction: Individual-study-data meta analysis was accomplished by giving authors data specifications tailored to their studies and requesting standardized patient-level data analysis.Analytical Approach: Individual-study-data meta analysis used a bivariate time-to-event model for interval-censored data from which discriminative ability (AUC) was characterized. NGAL cutoff concentrations at 95% sensitivity, 95% specificity, and optimal sensitivity and specificity were also estimated. Models incorporated as confounders the clinical setting and use versus nonuse of urine output as a criterion for AKI. A literature-based meta-analysis was also performed for all published studies including those for which the authors were unable to provide individual-study data analyses.Results: We included 52 observational studies involving 13,040 patients. We analyzed 30 data sets for the individual-study-data meta-analysis. For AKI, severe AKI, and AKI-D, numbers of events were 837, 304, and 103 for analyses of urinary NGAL, respectively; these values were 705, 271, and 178 for analyses of plasma NGAL. Discriminative performance was similar in both meta-analyses. Individual-study-data meta-analysis AUCs for urinary NGAL were 0.75 (95% CI, 0.73-0.76) and 0.80 (95% CI, 0.79-0.81) for severe AKI and AKI-D, respectively; for plasma NGAL, the corresponding AUCs were 0.80 (95% CI, 0.790.81) and 0.86 (95% CI, 0.84-0.8 6). Cutoff concentrations at 95% specificity for urinary NGAL were >580 ng/mL with 27% sensitivity for severe AKI and >589 ng/mL with 24% sensitivity for AKI-D. Corresponding cutoffs for plasma NGAL were >364 ng/mL with 44% sensitivity and >546 ng/mL with 26% sensitivity, respectively.Limitations: Practice variability in initiation of dialysis. Imperfect harmonization of data across studies. Conclusions: Urinary and plasma NGAL concentrations may identify patients at high risk for AKI in clinical research and practice. The cutoff concentrations reported in this study require prospective evaluation.
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4.
  • Björkman, Lena, 1965, et al. (författare)
  • The Neutrophil Response Induced by an Agonist for Free Fatty Acid Receptor 2 (GPR43) Is Primed by Tumor Necrosis Factor Alpha and by Receptor Uncoupling from the Cytoskeleton but Attenuated by Tissue Recruitment
  • 2016
  • Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 36:20, s. 2583-2595
  • Tidskriftsartikel (refereegranskat)abstract
    • Ligands with improved potency and selectivity for free fatty acid receptor 2 (FFA2R) have become available, and we here characterize the neutrophil responses induced by one such agonist (Cmp1) and one antagonist (CATPB). Cmp1 triggered an increase in the cytosolic concentration of Ca2+, and the neutrophils were then desensitized to Cmp1 and to acetate, a naturally occurring FFA2R agonist. The antagonist CATPB selectively inhibited responses induced by Cmp1 or acetate. The activated FFA2R induced superoxide anion secretion at a low level in naive blood neutrophils. This response was largely increased by tumor necrosis factor alpha (TNF-alpha) in a process associated with a recruitment of easily mobilizable granules, but neutrophils recruited to an aseptic inflammation in vivo were nonresponding. Superoxide production induced by Cmp1 was increased in latrunculin A-treated neutrophils, but no reactivation of desensitized FFA2R was induced by this drug, suggesting that the cytoskeleton is not directly involved in terminating the response. The functional and regulatory differences between the receptors that recognize short-chain fatty acids and formylated peptides, respectively, imply different roles of these receptors in the orchestration of inflammation and confirm the usefulness of a selective FFA2R agonist and antagonist as tools for the exploration of the precise role of the FFA2R.
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5.
  • Filevich, Elisa, et al. (författare)
  • Day2day : Investigating daily variability of magnetic resonance imaging measures over half a year
  • 2017
  • Ingår i: BMC Neuroscience. - : BioMed Central (BMC). - 1471-2202. ; 18:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Most studies of brain structure and function, and their relationships to cognitive ability, have relied on inter-individual variability in magnetic resonance (MR) images. Intra-individual variability is often ignored or implicitly assumed to be equivalent to the former. Testing this assumption empirically by collecting enough data on single individuals is cumbersome and costly. We collected a dataset of multiple MR sequences and behavioural covariates to quantify and characterize intra-individual variability in MR images for multiple individuals. Methods and design: Eight participants volunteered to undergo brain scanning 40-50 times over the course of 6 months. Six participants completed the full set of sessions. T1-weighted, T2*-weighted during rest, T2-weighted high-resolution hippocampus, diffusion-tensor imaging (DTI), and proton magnetic resonance spectroscopy sequences were collected, along with a rich set of stable and time-varying physical, behavioural and physiological variables. Participants did not change their lifestyle or participated in any training programs during the period of data collection. Conclusion: This imaging dataset provides a large number of MRI scans in different modalities for six participants. It enables the analysis of the time course and correlates of intra-individual variability in structural, chemical, and functional aspects of the human brain.
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6.
  • Kaya, Ibrahim, et al. (författare)
  • On-Tissue Chemical Derivatization of Catecholamines Using 4-(N-Methyl)pyridinium Boronic Acid for ToF-SIMS and LDI-ToF Mass Spectrometry Imaging
  • 2018
  • Ingår i: Analytical Chemistry. - 0003-2700 .- 1520-6882. ; 90:22, s. 13580-13590
  • Tidskriftsartikel (refereegranskat)abstract
    • The analysis of small polar compounds with ToF-SIMS and MALDI-ToF-MS have been generally hindered by low detection sensitivity, poor ionization efficiency, ion suppression, analyte in-source fragmentation, and background spectral interferences from either a MALDI matrix and/or endogenous tissue components. Chemical derivatization has been a well-established strategy for improved mass spectrometric detection of many small molecular weight endogenous compounds in tissues. Here, we present a devised strategy to selectively derivatize and sensitively detect catecholamines with both secondary ion ejection and laser desorption ionization strategies, which are used in many imaging mass spectrometry (IMS) experiments. Chemical derivatization of catecholamines was performed by a reaction with a synthesized permanent pyridinium-cation-containing boronic acid molecule, 4-(N-methyl)pyridinium boronic acid, through boronate ester formation (boronic acid-diol reaction). The derivatization facilitates their sensitive detection with ToF-SIMS and LDI-ToF mass spectrometric techniques. 4-(N-Methyl)pyridinium boronic acid worked as a reactive matrix for catecholamines with LDI and improved the sensitivity of detection for both SIMS and LDI, while the isotopic abundances of the boron atom reflect a unique isotopic pattern for derivatized catecholamines in MS analysis. Finally, the devised strategy was applied, as a proof of concept, for on-tissue chemical derivatization and GCIB-ToF-SIMS (down to 3 μm per pixel spatial resolution) and LDI-ToF mass spectrometry imaging of dopamine, epinephrine, and norepinephrine in porcine adrenal gland tissue sections. MS/MS using collision-induced dissociation (CID)-ToF-ToF-SIMS was subsequently employed on the same tissue sections after SIMS and LDI mass spectrometry imaging experiments, which provided tandem MS information for the validation of the derivatized catecholamines in situ. This methodology can be a powerful approach for the selective and sensitive ionization/detection and spatial localization of diol-containing molecules such as aminols, vic-diols, saccharides, and glycans along with catecholamines in tissue sections with both SIMS and LDI/MALDI-MS techniques. © 2018 American Chemical Society.
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7.
  • Lindstrom, Ann-Charlotte, et al. (författare)
  • Nationwide case-control study of risk factors and outcomes for community-acquired sepsis
  • 2021
  • Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Sepsis is the main cause of death in the intensive care units (ICU) and increasing incidences of ICU admissions for sepsis are reported. Identification of patients at risk for sepsis and poor outcome is therefore of outmost importance. We performed a nation-wide case-control study aiming at identifying and quantifying the association between co-morbidity and socio-economic factors with intensive care admission for community-acquired sepsis. We also explored 30-day mortality. All adult patients (n=10,072) with sepsis admitted from an emergency department to an intensive care unit in Sweden between 2008 and 2017 and a control population (n=50,322), matched on age, sex and county were included. In the sepsis group, 69% had a co-morbid condition at ICU admission, compared to 31% in the control group. Multivariable conditional logistic regression analysis was performed and there was a large variation in the influence of different risk factors associated with ICU-admission, renal disease, liver disease, metastatic malignancy, substance abuse, and congestive heart failure showed the strongest associations. Low income and low education level were more common in sepsis patients compared to controls. The adjusted OR for 30-day mortality for sepsis patients was 132 (95% CI 110-159) compared to controls.
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8.
  • Martensson, Johan, et al. (författare)
  • Association of plasma neutrophil gelatinase-associated lipocalin (NGAL) with sepsis and acute kidney dysfunction
  • 2013
  • Ingår i: Biomarkers. - 1354-750X .- 1366-5804. ; 18:4, s. 349-356
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Neutrophil gelatinase-associated lipocalin (NGAL) is secreted by injured kidney cells as well as by activated neutrophils in response to bacterial infections. We assessed the influence of acute renal dysfunction on the association between plasma NGAL and sepsis. Methods: NGAL was measured daily in 138 critically ill patients. Simultaneous recordings of sepsis status and fluctuations in renal function were made. Results: Elevated NGAL was associated with sepsis independent of level of acute renal dysfunction. A cut-off value of 98 ng/mL distinguished sepsis from systemic inflammation with high sensitivity (0.77) and specificity (0.79). Conclusions: Plasma NGAL can help clinicians to identify bacterial infections in critically ill patients.
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9.
  • Martensson, Johan, et al. (författare)
  • Immunoassays distinguishing between HNL/NGAL released in urine from kidney epithelial cells and neutrophils
  • 2012
  • Ingår i: Clinica Chimica Acta. - 0009-8981 .- 1873-3492. ; 413:19-20, s. 1661-1667
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The distinction between monomeric human neutrophil lipocalin/neutrophil gelatinase-associated lipocalin (HNL/NGAL), secreted by injured kidney tubular cells, and dimeric HNL/NGAL, released by activated neutrophils, is important to accurately diagnose acute kidney injury (AKI).Methods: 132 urine samples from 44 intensive care unit (ICU) patients and five urine samples from non-ICU patients with urinary tract infections (UTIs) were analyzed by two monoclonal enzyme-linked immunosorbent assays (ELISA-1 and ELISA-2). The presence of monomeric and/or dimeric HNL/NGAL in each sample was visualized by Western blotting.Results: The ELISA-1 detected both monomeric and dimeric HNL/NGAL whereas the ELISA-2 almost exclusively detected dimeric HNL/NGAL with an area under the receiver-operating characteristics curve (AuROC) of 0.90. The ELISA-1/ELISA-2 ratio detected the monomeric form with an AuROC of 0.92. In 32 AKI patients, dimer-specific EUSA-2 levels decreased pre-AKI whereas the monomer-specific ELISA-1/ELISA-2 ratio gradually increased beyond AKI diagnosis. High EUSA-2 levels and/or low ELISA-1/ELISA-2 ratios detected a predominance of dimeric HNL/NGAL in urine from the patients with tills.Conclusions: In combination, our two ELISAs distinguish monomeric HNL/NGAL, produced by the kidney epithelium, from dimeric HNL/NGAL, released by neutrophils during AKI development, as well as reduce the confounding effect of neutrophil involvement when bacteriuria is present.
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10.
  • Martensson, Johan, et al. (författare)
  • Neutrophil gelatinase-associated lipocalin in adult septic patients with and without acute kidney injury
  • 2010
  • Ingår i: Intensive Care Medicine. - 0342-4642 .- 1432-1238. ; 36:8, s. 1333-1340
  • Tidskriftsartikel (refereegranskat)abstract
    • To study the impact of inflammation/sepsis on the concentrations of neutrophil gelatinase-associated lipocalin (NGAL) in plasma and urine in adult intensive care unit (ICU) patients and to estimate the predictive properties of NGAL in plasma and urine for early detection of acute kidney injury (AKI) in patients with septic shock. Sixty-five patients admitted to the general ICU at the Karolinska University Hospital Solna, Sweden, with normal plasma creatinine were assessed for eligibility. Twenty-seven patients with systemic inflammatory response syndrome (SIRS), severe sepsis, or septic shock without AKI and 18 patients with septic shock and concomitant AKI were included in the final analysis. Plasma and urine were analyzed twice daily for plasma NGAL (pNGAL), C-reactive protein (CRP), procalcitonin, myeloperoxidase, plasma cystatin C, plasma creatinine, urine NGAL (uNGAL), urine cystatin C, and urine alpha 1-microglobulin. Of the 45 patients, 40 had elevated peak levels of pNGAL. Peak levels of pNGAL were not significantly different between septic shock patients with and without AKI. Peak levels of uNGAL were below the upper reference limit in all but four patients without AKI. uNGAL was a good predictor (area under ROC 0.86) whereas pNGAL was a poor predictor (area under ROC 0.67) for AKI within the next 12 h in patients with septic shock. pNGAL is raised in patients with SIRS, severe sepsis, and septic shock and should be used with caution as a marker of AKI in ICU patients with septic shock. uNGAL is more useful in predicting AKI as the levels are not elevated in septic patients without AKI.
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