26 results on '"Ulvestad M"'
Search Results
2. Comparison of different reference values for lung function, and implications of inconsistent use nationwide
- Author
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Mangseth, H, primary, Sikkeland, L I B, additional, Myrdal, O H, additional, Ulvestad, M, additional, Kongerud, J, additional, Durheim, M T, additional, and Lund, M B, additional
- Published
- 2022
- Full Text
- View/download PDF
3. 1459P Long-term management and outcomes in gastroesophageal cancer in Norway
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Kolstad, A., Hjortland, G.O., Nilssen, Y., Emanuel, G., Ulvestad, M., Areffard, A., and Aahlin, E.
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- 2024
- Full Text
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4. Acne and dairy products in adolescence: results from a Norwegian longitudinal study
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Ulvestad, M., Bjertness, E., Dalgard, F., and Halvorsen, J. A.
- Published
- 2017
- Full Text
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5. Impact of OATP1B1, MDR1, and CYP3A4 Expression in Liver and Intestine on Interpatient Pharmacokinetic Variability of Atorvastatin in Obese Subjects
- Author
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Ulvestad, M, Skottheim, I B, Jakobsen, G S, Bremer, S, Molden, E, Åsberg, A, Hjelmesæth, J, Andersson, T B, Sandbu, R, and Christensen, H
- Published
- 2013
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6. An Accessible Comparison Of Traditional Statistical And Machine Learning Approaches To Analysis Of Real World Data: Which, When And Why?
- Author
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Merinopoulou, E, primary, Oguz, M, additional, Chu, BC, additional, McDonald, L, additional, Ulvestad, M, additional, Cox, A, additional, and Ramagopalan, S, additional
- Published
- 2017
- Full Text
- View/download PDF
7. Acne and dairy products in adolescence: results from a Norwegian longitudinal study
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Ulvestad, M., primary, Bjertness, E., additional, Dalgard, F., additional, and Halvorsen, J.A., additional
- Published
- 2016
- Full Text
- View/download PDF
8. Impact of OATP1B1, MDR1 and CYP3A4 expression in liver and intestine on interpatient pharmacokinetic variability of atorvastatin in obese subjects
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Ulvestad, M, primary, Skottheim, I. B., additional, Signe Jakobsen, G, additional, Bremer, S, additional, Molden, E, additional, Åsberg, A, additional, Hjelmesaeth, Jøran, additional, Andersson, T. B., additional, Sandbu, R, additional, and Christensen, H, additional
- Published
- 2015
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9. PRM217 - An Accessible Comparison Of Traditional Statistical And Machine Learning Approaches To Analysis Of Real World Data: Which, When And Why?
- Author
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Merinopoulou, E, Oguz, M, Chu, BC, McDonald, L, Ulvestad, M, Cox, A, and Ramagopalan, S
- Published
- 2017
- Full Text
- View/download PDF
10. Impact of OATP1B1, MDR1, and CYP3A4 Expression in Liver and Intestine on Interpatient Pharmacokinetic Variability of Atorvastatin in Obese Subjects
- Author
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Ulvestad, M, primary, Skottheim, I B, additional, Jakobsen, G S, additional, Bremer, S, additional, Molden, E, additional, Åsberg, A, additional, Hjelmesæth, J, additional, Andersson, T B, additional, Sandbu, R, additional, and Christensen, H, additional
- Published
- 2012
- Full Text
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11. Real-World Treatment Patterns and Survival Outcomes for Patients with Non-Metastatic Non-Small-Cell Lung Cancer in Sweden: A Nationwide Registry Analysis from the I-O Optimise Initiative.
- Author
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Oskarsdottir GN, Lampa E, Berglund A, Rosengren L, Ulvestad M, Boros M, Daumont MJ, Rault C, Emanuel G, Leal C, Schoemaker MJ, and Wagenius G
- Abstract
Non-small-cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide, with ~40-50% of patients diagnosed with non-metastatic disease (stages IA-IIIC). The treatment landscape is evolving rapidly as immunotherapies and targeted therapy are introduced in the non-metastatic setting, creating a need to assess patient outcomes prior to their introduction. This real-world study using Swedish National Lung Cancer Registry data examined outcomes (overall survival (OS) and time to next treatment or death (TTNTD)) and treatment patterns for adults diagnosed with non-metastatic NSCLC. Baseline characteristics and OS from diagnosis were described for all patients; OS, treatment patterns, and TTNTD from treatment start were described for the treatment subgroup (patients diagnosed from 2014 onwards), stratified by disease stage and initial treatment. OS and TTNTD were described using the Kaplan-Meier estimator. The overall population (2008-2019) included 17,433 patients; the treatment subgroup included 5147 patients. Median OS (interquartile range) overall ranged from 83.3 (31.6-165.3) months (stage I patients) to 10.4 (4.3-24.2) months (stage IIIB patients). Among the treatment subgroup, median OS and TTNTD were longest among patients receiving surgery versus other anticancer treatments. These findings provide a baseline upon which to evaluate the epidemiology of non-metastatic NSCLC as newer treatments are introduced.
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- 2024
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12. Comparison of different reference values for lung function: implications of inconsistent use among centers.
- Author
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Mangseth H, Sikkeland LIB, Durheim MT, Ulvestad M, Myrdal OH, Kongerud J, and Lund MB
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- Adult, Male, Female, Humans, Reference Values, Spirometry methods, Respiratory Function Tests, Forced Expiratory Volume, Vital Capacity, Respiratory Physiological Phenomena, Lung
- Abstract
Background: For interpretation of pulmonary function tests (PFTs), reference values based on sex, age, height and ethnicity are needed. In Norway, the European Coal and Steel Community (ECSC) reference values remain widely used, in spite of recommendations to implement the more recent Global Lung Function Initiative (GLI) reference values., Objective: To assess the effects of changing from ECSC to GLI reference values for spirometry, DLCO and static lung volumes, using a clinical cohort of adults with a broad range in age and lung function., Methods: PFTs from 577 adults (18-85 years, 45% females) included in recent clinical studies were used to compare ECSC and GLI reference values for FVC, FEV1, DLCO, TLC and RV. Percent predicted and lower limit of normal (LLN) were calculated. Bland-Altman plots were used to assess agreement between GLI and ECSC % predicted values., Results: In both sexes, GLI % predicted values were lower for FVC and FEV1, and higher for DLCO and RV, compared to ECSC. The disagreement was most pronounced in females, with mean (SD) difference 15 (5) percent points (pp) for DLCO and 17 (9) pp for RV (p < 0.001). With GLI, DLCO was below LLN in 23% of the females, with ECSC in 49% of the females., Conclusions: The observed differences between GLI and ECSC reference values are likely to entail significant consequences with respect to criteria for diagnostics and treatment, health care benefits and inclusion in clinical trials. To ensure equity of care, the same reference values should be consistently implemented across centers nationwide., (© 2023. The Author(s).)
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- 2023
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13. Changes in primary care management of atrial fibrillation patients following the shift from warfarin to non-vitamin K antagonist oral anticoagulants: a Norwegian population based study.
- Author
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Halvorsen S, Smith JA, Söderdahl F, Thuresson M, Solli O, Ulvestad M, and Jonasson C
- Subjects
- Anticoagulants therapeutic use, Female, Humans, Longitudinal Studies, Male, Primary Health Care, Retrospective Studies, Warfarin therapeutic use, Atrial Fibrillation drug therapy, Stroke epidemiology
- Abstract
Background: To assess baseline characteristics, drug utilisation and healthcare use for oral anticoagulants (OACs) following the introduction of non-vitamin K antagonist oral anticoagulants among patients with atrial fibrillation in primary care in Norway., Methods: In this retrospective longitudinal cohort study, 92,936 patients with atrial fibrillation were identified from the Norwegian Primary Care Registry between 2010 and 2018. Linking to the Norwegian Prescription Database, we identified 64,112 patients (69.0%) treated with OACs and 28,824 (31%) who were untreated. Participants were followed until 15 May 2019, death, or loss to follow-up, whichever came first. For each OAC, predictors of initiation were assessed by modelling the probability of initiating the OAC using logistic regression, and predictors of the first switch after index date were assessed using multivariable Cox proportional hazards models. The numbers of primary care visits per quarter by index OAC were plotted and analysed with negative binomial regression analyses offset for the log of days at risk., Results: Patients treated with OACs were older, had more comorbidities, and higher CHA
2 DS2 -VASc scores than untreated patients. However, the mean CHA2 DS2 -VASc in the non-OAC group was 1.58 for men and 3.13 for women, suggesting an indication for OAC therapy. The percentage of patients with atrial fibrillation initiating OACs increased from 59% in 2010 to 79% in 2018. Non-vitamin K antagonist oral anticoagulant use increased throughout the study period to 95% of new OAC-treated patients in 2018, and switches from warfarin to non-vitamin K antagonist oral anticoagulants were common. The persistence of OAC treatment was > 60% after four years, with greatest persistence for apixaban. Patients treated with non-vitamin K antagonist oral anticoagulants had fewer primary care visits compared with those treated with warfarin (incidence rate ratio: 0.73, 95% confidence interval 0.71 to 0.75)., Conclusion: In this Norwegian primary care study, we found that the shift from warfarin to non-vitamin K antagonist oral anticoagulants was successful with 95% use in patients initiating OACs in 2018, and associated with fewer general practitioner visits. Persistence with OACs was high, particularly for apixaban. However, many patients eligible for treatment with OACs remained untreated., (© 2022. The Author(s).)- Published
- 2022
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14. CHA 2 DS 2 -VASc and HAS-BLED risk scores and real-world oral anticoagulant prescribing decisions in atrial fibrillation.
- Author
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Besford M, Leahy TP, Sammon C, Ulvestad M, Carroll R, Mehmud F, Alikhan R, and Ramagopalan S
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- Anticoagulants therapeutic use, Humans, Retrospective Studies, Risk Assessment, Risk Factors, Atrial Fibrillation complications, Atrial Fibrillation drug therapy, Stroke
- Abstract
Background: Guidelines indicate that oral anticoagulant (OAC) treatment decisions in atrial fibrillation should be based on a balanced consideration of thromboembolic and bleeding risk. Materials & methods: A retrospective cohort of nonvalvular atrial fibrillation patients were identified. Univariate logistic regression and conditional inference trees were used to quantify the importance of the CHA
2 DS2 -VASc and modified HAS-BLED scores and their individual components on OAC treatment decisions. Results: The individual components of these risk scores provided more distinguishability between treated and untreated patients than the risk scores themselves, with bleeding risk factors strongly associated with nontreatment. Conclusion: While individual components of risk scores drive OAC treatment decisions according to guidelines, the relationship between bleeding risk factors and nontreatment warrants further consideration.- Published
- 2021
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15. Effect of high-intensity training on bone health and body composition in lung transplant recipients: A secondary analysis of a randomized controlled trial.
- Author
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Ulvestad M, Godang K, Durheim MT, Kongerud JS, Brit Lund M, Bollerslev J, and Edvardsen E
- Subjects
- Absorptiometry, Photon, Humans, Lung, Body Composition, Bone Density, High-Intensity Interval Training, Transplant Recipients
- Abstract
Background: Loss of bone mineral and skeletal muscle mass is common after lung transplantation (LTx), and physical activity (PA) may prevent further deterioration. We aimed to assess the effects of 20-week high-intensity training (HIT) on body composition, bone health, and PA in LTx recipients, 6-60 months after surgery., Methods: In a randomized controlled trial, 51 LTx recipients underwent Dual-energy X-ray absorptiometry (DXA), and PA level and sedentary time were objectively recorded by accelerometers for seven consecutive days. Of these, 39 participants completed the study, including 19 participants in the HIT group and 20 participants in the standard care group., Results: Following the intervention, ANCOVA models revealed a nonsignificant between-group difference for change in lean body mass (LBM) and bone mineral density (BMD) of the lumbar spine of 0.4% (95% CI = -3.2, 1.5) (p = .464) and 1.0% (95% CI=-1.3, 3.4) (p = .373), respectively. Trabecular bone score (TBS) of the lumbar spine (L1-L4), however, increased by 2.2 ± 5.0% in the exercise group and decreased by -1.6 ± 5.9% in the control group, giving a between-group difference of 3.8% (95% CI=0.1, 7.5) (p = .043). There were no between-group differences in PA or sedentary time., Conclusion: High-intensity training after LTx improved TBS significantly, but not PA, LBM or BMD., (© 2021 The Authors. Clinical Transplantation published by John Wiley & Sons Ltd.)
- Published
- 2021
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16. Oral Anticoagulation Therapy for Venous Thromboembolism in Norway: Time Trends and Treatment Patterns.
- Author
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Ghanima W, Schultze A, Donaldson R, Brodin E, Halvorsen S, Graham S, Carroll R, Ulvestad M, and Lambrelli D
- Subjects
- Administration, Oral, Anticoagulants therapeutic use, Cohort Studies, Humans, Pyridones therapeutic use, Rivaroxaban therapeutic use, Warfarin therapeutic use, Venous Thromboembolism drug therapy, Venous Thromboembolism epidemiology
- Abstract
Purpose: Data describing treatment patterns of patients with venous thromboembolism (VTE) patients in Scandinavia are scarce. This study sought to address this scarcity by describing demographic and clinical characteristics, trends in the use of oral anticoagulants (OACs), and treatment patterns in patients treated for VTE in Norway between 2013 and 2017., Methods: Using data from Norway's nationwide registries, a cohort study included patients newly (after 2008) treated OACs who were diagnosed with VTE between January 2013 and December 2017 and were dispensed an OAC (warfarin, apixaban, rivaroxaban, dabigatran, or edoxaban) within 30 days. Patient characteristics and the percentage of patients with VTE who initiated treatment with each OAC for each calendar year were reported. Initial therapy persistence was assessed using Kaplan-Meier curves and compared between the OAC groups using the log-rank test., Findings: The comorbidity burden was similar between patients taking warfarin and those taking apixaban but lower among patients taking rivaroxaban. Direct oral anticoagulant (DOAC) use increased from 33.2% to 93.6% during the study period, whereas warfarin use decreased. Persistence was higher in the apixaban cohort compared with the warfarin cohort, with the difference mostly apparent after 6 months, whereas persistence was similar between the patients taking rivaroxaban and those taking warfarin., Implications: Between 2013 and 2017, DOAC use among patients with VTEs increased markedly in Norway, whereas the use of warfarin decreased. Patients taking apixaban had higher persistence compared with those taking warfarin, whereas patients taking warfarin and those taking rivaroxaban had similar persistence. Further studies with longer follow-up are required to examine the use of extended OAC treatment for VTE., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
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17. Incidence and prevalence of venous thromboembolism in Norway 2010-2017.
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Ghanima W, Brodin E, Schultze A, Shepherd L, Lambrelli D, Ulvestad M, Ramagopalan S, and Halvorsen S
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- Humans, Incidence, Norway epidemiology, Prevalence, Risk Factors, Pulmonary Embolism, Venous Thromboembolism epidemiology
- Published
- 2020
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18. Effect of high-intensity training on peak oxygen uptake and muscular strength after lung transplantation: A randomized controlled trial.
- Author
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Ulvestad M, Durheim MT, Kongerud JS, Lund MB, and Edvardsen E
- Subjects
- Exercise Test, Female, Follow-Up Studies, Humans, Male, Middle Aged, Oxygen Consumption physiology, Postoperative Complications prevention & control, Exercise Therapy methods, High-Intensity Interval Training methods, Lung Transplantation, Muscle Strength physiology, Quality of Life
- Abstract
Background: Peak oxygen uptake (VO
2peak ) remains low after lung transplantation (LTx). We evaluated the effect of high-intensity interval training (HIIT) on VO2peak , muscular strength, health-related quality of life (HRQOL), pulmonary function, and physical function after LTx., Methods: In this randomized controlled trial, 54 participants were enrolled from 6 to 60 months after LTx. The HIIT group (n = 25) followed a supervised HIIT program, consisting of endurance and strength trainings 3 times a week for 20 weeks. The control group (n = 29) received usual care. The primary outcome was a change in VO2peak measured by cardiopulmonary exercise testing. The secondary outcomes were changes in 1-repetition maximum (1RM) for arm press and leg press, HRQOL (36-Item Short-Form Health Survey [SF-36]), pulmonary function (forced expiratory volume in 1 sec, diffusing capacity of the lungs for carbon monoxide), and physical function (1RM in handgrip, 15-sec stair run, and 30-sec chair stand)., Results: A total of 46 participants completed the study, including 23 of 25 in the intervention group. For the primary outcome, the intention-to-treat analysis revealed a non-significant between-group difference for change in VO2peak of 0.7 ml/(kg.min) (95% CI = ‒0.3, 1.8) (p = 0.17). The between-group differences for 1RM arm press and leg press and mental aspect of SF-36 were 4.9 kg (95% CI = ‒0.1, 9.9) (p = 0.05), 11.6 kg (95% CI = 0.1, 23.0) (p < 0.05), and 5.7 kg (95% CI = 0.9, 10.4) (p = 0.02), respectively. There were no between-group differences in pulmonary function or physical function. When excluding participants with an attendance of <70% (n = 16), the between-group difference for VO2peak was 1.2 ml/(kg.min) (95% CI = 0.1, 2.4) (p = 0.032)., Conclusions: HIIT improved muscular strength and HRQOL but did not improve VO2peak more than usual care after LTx. However, with acceptable adherence, HIIT appears to have beneficial effects on VO2peak ., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2020
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19. Pulmonary function and high-resolution computed tomography in outdoor rock drillers exposed to crystalline silica.
- Author
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Ulvestad B, Ulvestad M, Skaugset NP, Aaløkken TM, Günther A, Clemm T, Lund MB, and Ellingsen DG
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- Adult, Aged, Construction Industry, Humans, Male, Middle Aged, Norway epidemiology, Particulate Matter adverse effects, Pulmonary Fibrosis, Respiratory Function Tests, Silicosis, Smokers, Tomography, X-Ray Computed, Lung Diseases, Obstructive diagnostic imaging, Lung Diseases, Obstructive physiopathology, Occupational Exposure adverse effects, Silicon Dioxide adverse effects
- Abstract
Objectives: Chronic obstructive pulmonary disease and silicosis are associated with exposure to crystalline silica. We determined the exposure to respirable crystalline silica and estimated exposure-response relationships between cumulative exposure and pulmonary function in outdoor rock drillers., Methods: 136 rock drillers and 48 referents were recruited from three heavy construction companies. 98 air samples were collected by personal sampling for determination of respirable particulate matter and crystalline silica. Information about individual job tasks, type of drilling equipment and years of exposure in different job categories was obtained by interview. Cumulative exposure to crystalline silica was calculated for all workers. Pulmonary function was assessed by spirometry. A subgroup of 39 subjects with high cumulative exposure to crystalline silica underwent high-resolution computed tomography (HRCT)., Results: Cumulative exposure (mean (min-max)) to crystalline silica was 0.69 mg٠years m
-3 (0.01-5.89) in the exposed group. Mean time of exposure among rock drillers was 10.7 years (1-42). Compared with referents, the rock drillers had a lower forced expiratory volume in one second/forced vital capacity ratio (79.4 vs 81.4, p<0.05) and maximal mid-expiratory flow% (85.6 vs 93.9, p<0.05). Further, by stratifying the exposed workers into three equally large groups, a dose-response relationship was demonstrated in the highest exposed group, also in never smokers, at a mean cumulative exposure of 21.7 years at 0.08 mg٠m-3 /years. Silicosis was not detected in HRCT, but other patterns of fibrosis and emphysema were seen., Conclusions: Outdoor rock drillers exposed to crystalline silica had significantly lower pulmonary function than referents, and signs of airflow obstruction. Silicosis was not detected., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)- Published
- 2020
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20. Cardiorespiratory Fitness and Physical Activity following Lung Transplantation: A National Cohort Study.
- Author
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Ulvestad M, Durheim MT, Kongerud JS, Hansen BH, Lund MB, and Edvardsen E
- Subjects
- Adult, Aged, Cardiovascular Deconditioning, Cohort Studies, Cystic Fibrosis surgery, Exercise Test, Exercise Tolerance, Female, Forced Expiratory Volume, Hemoglobins metabolism, Humans, Lung Diseases, Interstitial surgery, Male, Middle Aged, Norway, Pulmonary Disease, Chronic Obstructive surgery, Pulmonary Gas Exchange, Young Adult, Cardiorespiratory Fitness, Exercise, Lung Transplantation, Oxygen Consumption
- Abstract
Background: Low cardiorespiratory fitness and inactivity are common after lung transplantation (LTx). The causes of exercise intolerance are incompletely understood., Objectives: The aim of this study was to objectively assess cardiorespiratory fitness and physical activity, evaluate causes of exercise intolerance, and explore clinical factors associated with cardiorespiratory fitness after bilateral LTx (BLTx)., Materials and Methods: Peak oxygen uptake (V∙O2peak) and exercise-limiting factors were evaluated by a treadmill cardiopulmonary exercise test (CPET) 6-60 months after BLTx. Physical activity was measured with accelerometers, and results were compared with Norwegian normative data and the World Health Organization's (WHO) recommendations for physical activity., Results: In 54 included BLTx recipients (mean age 50 ± 15 years, 50% females), V∙O2peak (mL × kg-1 × min-1) was 21.8 ± 7.7 for men and 22.4 ± 6.2 for women, corresponding to 57 ± 17 and 70 ± 12% of predicted, respectively. Three patients (6%) met criteria for normal V∙O2peak. Deconditioning limited V∙O2peak in 22 patients (41%), while ventilatory limitation and abnormal gas exchange were observed in 14 (26%) and 20 (37%) patients, respectively (some had more than 1 finding). Forty-three patients (86%) did not meet the WHO physical activity recommendations. There was a moderate correlation between V∙O2peak and physical activity (r = 0.642, p < 0.01). Body mass index, physical activity, forced expiratory volume after 1 second, sex, and hemoglobin together accounted for 73% of the variability in V∙O2peak., Conclusions: Low cardiorespiratory fitness was observed in the majority of BLTx recipients. Both deconditioning and cardiopulmonary limitations were common findings. Nearly 90% were classified as being inactive according to physical activity recommendations. CPET appears to identify a deconditioned subgroup of BLTx recipients for whom exercise training may be especially beneficial., (© 2020 The Author(s) Published by S. Karger AG, Basel.)
- Published
- 2020
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21. The changing face of venous thromboembolism management in England.
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Ramagopalan SV, Carroll R, Ulvestad M, Mehmud F, and Alikhan R
- Subjects
- Administration, Oral, England epidemiology, Humans, Incidence, Venous Thromboembolism epidemiology, Vitamin K antagonists & inhibitors, Anticoagulants administration & dosage, Fibrinolytic Agents administration & dosage, Venous Thromboembolism drug therapy
- Abstract
Aim: Venous thromboembolism (VTE), which comprises deep vein thrombosis and pulmonary embolism, poses a global disease burden. Vitamin K antagonists have traditionally been the mainstay of treatment; however, the non-vitamin K oral anticoagulants (NOACs) are emerging as an alternative. The relative use of these treatment classes in the real world is unknown. Patients & methods: We performed a retrospective study using data from the UK Clinical Practice Research Datalink to understand VTE treatment patterns. Results: NOACs have unseated vitamin K antagonist as the main form of VTE patient treatment in England. Conclusion: The data highlight how comfortable physicians have become in using NOACs to treat VTE in England and it is likely that the increasing use of NOACs will continue.
- Published
- 2019
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22. Drug metabolizing enzyme and transporter protein profiles of hepatocytes derived from human embryonic and induced pluripotent stem cells.
- Author
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Ulvestad M, Nordell P, Asplund A, Rehnström M, Jacobsson S, Holmgren G, Davidson L, Brolén G, Edsbagge J, Björquist P, Küppers-Munther B, and Andersson TB
- Subjects
- ATP Binding Cassette Transporter, Subfamily B, ATP Binding Cassette Transporter, Subfamily B, Member 1 genetics, ATP Binding Cassette Transporter, Subfamily B, Member 1 metabolism, ATP Binding Cassette Transporter, Subfamily G, Member 2, ATP-Binding Cassette Transporters genetics, ATP-Binding Cassette Transporters metabolism, Cell Line, Cytochrome P-450 Enzyme System genetics, Hepatocytes enzymology, Humans, Membrane Transport Proteins genetics, Multidrug Resistance-Associated Protein 2, Multidrug Resistance-Associated Proteins genetics, Multidrug Resistance-Associated Proteins metabolism, Neoplasm Proteins genetics, Neoplasm Proteins metabolism, Organic Cation Transporter 1 genetics, Organic Cation Transporter 1 metabolism, Real-Time Polymerase Chain Reaction, Cytochrome P-450 Enzyme System metabolism, Embryonic Stem Cells metabolism, Hepatocytes metabolism, Induced Pluripotent Stem Cells metabolism, Membrane Transport Proteins metabolism
- Abstract
Human embryonic and induced pluripotent stem cell-derived hepatocytes (hESC-Hep and hiPSC-Hep) have the potential to provide relevant human in vitro model systems for toxicity testing and drug discovery studies. In this study, the expression and function of important drug metabolizing cytochrome P450 (CYP) enzymes and transporter proteins in hESC-Hep and hiPSC-Hep were compared to cryopreserved human primary hepatocytes (hphep) and HepG2 cells. Overall, CYP activities in hESC-Hep and hiPSC-Hep were much lower than in hphep cultured for 4 h, but CYP1A and 3A activities were comparable to levels in hphep cultured for 48h (CYP1A: 35% and 26% of 48 h hphep, respectively; CYP3A: 80% and 440% of 48 h hphep, respectively). Importantly, in hESC-Hep and hiPSC-Hep, CYP activities were stable or increasing for at least one week in culture which was in contrast to the rapid loss of CYP activities in cultured hphep between 4 and 48 h after plating. With regard to transporters, in hESC-Hep and hiPSC-Hep, pronounced NTCP activity (17% and 29% of 4 h hphep, respectively) and moderate BSEP activity (6% and 8% of 4 h hphep, respectively) were observed. Analyses of mRNA expression and immunocytochemistry supported the observed CYP and transporter activities and showed expression of additional CYPs and transporters. In conclusion, the stable expression and function of CYPs and transporters in hESC-Hep and hiPSC-Hep for at least one week opens up the possibility to reproducibly perform long term and extensive studies, e.g. chronic toxicity testing, in a stem cell-derived hepatic system., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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23. Evaluation of organic anion-transporting polypeptide 1B1 and CYP3A4 activities in primary human hepatocytes and HepaRG cells cultured in a dynamic three-dimensional bioreactor system.
- Author
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Ulvestad M, Darnell M, Molden E, Ellis E, Åsberg A, and Andersson TB
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- Adult, Aged, 80 and over, Cells, Cultured, Enzyme Activation physiology, Female, Humans, Liver-Specific Organic Anion Transporter 1, Bioreactors, Cell Culture Techniques methods, Cytochrome P-450 CYP3A metabolism, Hepatocytes metabolism, Organic Anion Transporters metabolism
- Abstract
The long-term stability of liver cell functions is a major challenge when studying hepatic drug transport, metabolism, and toxicity in vitro. The aim of the present study was to investigate organic anion-transporting polypeptide (OATP) 1B1 and CYP3A4 activities in fresh primary human hepatocytes and differentiated cryopreserved HepaRG cells when cultured in a three-dimensional (3D) bioreactor system. OATP1B1 activity was determined by loss from media experiments of [(3)H]estradiol-17β-D-glucuronide and atorvastatin acid (ATA) for up to 7 days in culture. ATA metabolite formation was determined at days 3 to 4 to evaluate CYP3A4 activity. Overall, the results showed that freshly isolated human hepatocytes inoculated in the bioreactor retained OATP1B1 activity for at least 7 days, whereas in HepaRG cells no OATP1B1 activity was observed beyond day 2. The activity data were in agreement with immunohistochemical stainings, which showed that OATP1B1 protein expression was preserved for at least 9 days in fresh human hepatocytes, whereas OATP1B1 was expressed markedly lower in HepaRG cells after 9 days in culture. Fresh human hepatocytes and HepaRG cells exhibited similar CYP3A4 activity in bioreactor culture, and immunohistochemical stainings supported these findings. Activity and mRNA expression of OATP1B1 and CYP3A4 in primary human hepatocytes compared with HepaRG cells in fresh suspensions were in agreement with data obtained in bioreactor culture. In conclusion, freshly isolated human hepatocytes cultured in a 3D bioreactor system preserve both OATP1B1 and CYP3A4 activities, allowing long-term in vitro studies on drug disposition and toxicity.
- Published
- 2012
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24. In vitro evaluation of major in vivo drug metabolic pathways using primary human hepatocytes and HepaRG cells in suspension and a dynamic three-dimensional bioreactor system.
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Darnell M, Ulvestad M, Ellis E, Weidolf L, and Andersson TB
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- Adult, Aged, 80 and over, Cells, Cultured, Drug Evaluation, Preclinical methods, Female, Hepatocytes drug effects, Humans, Metabolic Networks and Pathways drug effects, Pharmaceutical Preparations administration & dosage, Suspensions, Bioreactors, Cell Culture Techniques methods, Hepatocytes metabolism, Metabolic Networks and Pathways physiology, Pharmaceutical Preparations metabolism
- Abstract
Major human specific metabolites, not detected during in vivo and in vitro preclinical studies, may cause unexpected drug interactions and toxicity in human and delays in clinical programs. Thus, reliable preclinical tools for the detection of major human metabolites are of high importance. The aim of this study was to compare major drug metabolic pathways in HepaRG cells, a human hepatoma cell line, to fresh human hepatocytes, cryopreserved human hepatocytes, and human in vivo data. Furthermore, the maintenance of cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) activities in a dynamic three-dimensional (3D) bioreactor were evaluated over time by using HepaRG cells and human hepatocytes. (14)C-diclofenac and a candidate from AstraZeneca's drug development program, (14)C-AZD6610, which are metabolized by P450 and UGT in vivo, were used as model substrates. The proportion of relevant biotransformation pathways of the investigated drug was clearly different in the various cell systems. The hydroxylation route was favored in primary human hepatocytes, whereas the glucuronidation route was favored in HepaRG cells. The human in vivo metabolite profile of AZD6610 was best represented by human hepatocytes, whereas all major diclofenac metabolites were detected in HepaRG cells. Moreover, the metabolite profiles in cryopreserved and fresh human hepatocytes were essentially the same. The liver bioreactor using both fresh human hepatocytes and HepaRG cells retained biotransformation capacity over 1 week. Thus, the incubation time can be increased from a few hours in suspension to several days in 3D cultures, which opens up for detection of metabolites from slowly metabolized drugs.
- Published
- 2012
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25. Natural gas and CO 2 price variation: impact on the relative cost-efficiency of LNG and pipelines.
- Author
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Ulvestad M and Overland I
- Abstract
THIS ARTICLE DEVELOPS A FORMAL MODEL FOR COMPARING THE COST STRUCTURE OF THE TWO MAIN TRANSPORT OPTIONS FOR NATURAL GAS: liquefied natural gas (LNG) and pipelines. In particular, it evaluates how variations in the prices of natural gas and greenhouse gas emissions affect the relative cost-efficiency of these two options. Natural gas is often promoted as the most environmentally friendly of all fossil fuels, and LNG as a modern and efficient way of transporting it. Some research has been carried out into the local environmental impact of LNG facilities, but almost none into aspects related to climate change. This paper concludes that at current price levels for natural gas and CO
2 emissions the distance from field to consumer and the volume of natural gas transported are the main determinants of transport costs. The pricing of natural gas and greenhouse emissions influence the relative cost-efficiency of LNG and pipeline transport, but only to a limited degree at current price levels. Because more energy is required for the LNG process (especially for fuelling the liquefaction process) than for pipelines at distances below 9100 km, LNG is more exposed to variability in the price of natural gas and greenhouse gas emissions up to this distance. If the prices of natural gas and/or greenhouse gas emission rise dramatically in the future, this will affect the choice between pipelines and LNG. Such a price increase will be favourable for pipelines relative to LNG.- Published
- 2012
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26. OATP1B1/1B3 activity in plated primary human hepatocytes over time in culture.
- Author
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Ulvestad M, Björquist P, Molden E, Asberg A, and Andersson TB
- Subjects
- Adult, Aged, Cells, Cultured, Estradiol analogs & derivatives, Estradiol metabolism, Female, Genotype, Humans, Liver-Specific Organic Anion Transporter 1, Male, Middle Aged, Organic Anion Transporters genetics, Organic Anion Transporters, Sodium-Independent genetics, Solute Carrier Organic Anion Transporter Family Member 1B3, Time Factors, Gene Expression Regulation physiology, Hepatocytes metabolism, Organic Anion Transporters metabolism, Organic Anion Transporters, Sodium-Independent metabolism
- Abstract
Primary human hepatocytes are widely used as an in vitro model for evaluation of drug metabolism and transport. However, it has been shown that the gene expression of many drug-metabolizing enzymes and transporters change in culture. The aim of the present study was to evaluate the activity of organic anion-transporting polypeptide 1B1 (OATP1B1) and 1B3 (OATP1B3) in plated primary human hepatocytes over time in culture. The uptake kinetics of the OATP1B1/1B3 substrate [(3)H]-estradiol-17β-d-glucuronide was determined in cells from five donors. An extensive and variable decrease in OATP1B1/1B3 activity and/or increase in passive diffusion was observed over time. Already after 6h in culture, the OATP1B1/1B3 activity was not possible to determine in liver cells from one donor, while after 24h, the uptake activity was not measurable in one additional donor. In the other three, the decrease in CL(int) (V(max)/K(m)) values ranged from 15% to 86% after 24h in culture compared to the values measured at 2h. Visual examination of OATP1B1 protein expression by confocal microscopy showed localization to the plasma membrane as expected, and an extensive decrease in OATP1B1 expression over time in culture supported the decline in activity. The significant reduction in SLCO1B1 and SLCO1B3 gene expression over time determined by RT-PCR also supported the loss of OATP1B1/1B3 activity. In conclusion, plated primary human hepatocytes are useful as an in vitro model for OATP1B1/1B3-mediated uptake studies, but the culture time may substantially change the uptake kinetics., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
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