92 results on '"Kristoffersen, L."'
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2. Chironomids with "M-fork". A reevaluation of the wing venation of the Corynoneura-group (Insecta, Diptera, Chironomidae)
- Author
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Sæther, Ole A., Kristoffersen, L, and BioStor
- Published
- 1996
3. Quantitative determination of zopiclone and zolpidem in whole blood by liquid–liquid extraction and UHPLC-MS/MS
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Eliassen, E. and Kristoffersen, L.
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- 2014
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4. Quantitative determination of fifteen basic pharmaceuticals in ante- and post-mortem whole blood by high pH mobile phase reversed phase ultra high performance liquid chromatography–tandem mass spectrometry
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Amundsen, I., Øiestad, Å.M.L., Ekeberg, D., and Kristoffersen, L.
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- 2013
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5. Relative validity of a food frequency questionnaire used in the Inter99 study
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Toft, U, Kristoffersen, L, Ladelund, S, Bysted, A, Jakobsen, J, Lau, C, Jørgensen, T, Borch-Johnsen, K, and Ovesen, L
- Published
- 2008
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6. The Dietary Quality Score: validation and association with cardiovascular risk factors: the Inter99 study
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Toft, U, Kristoffersen, L H, Lau, C, Borch-Johnsen, K, and Jørgensen, T
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- 2007
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7. Simultaneous determination of citalopram, fluoxetine, paroxetine and their metabolites in plasma by temperature-programmed packed capillary liquid chromatography with on-column focusing of large injection volumes
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Molander, P, Thomassen, A, Kristoffersen, L, Greibrokk, T, and Lundanes, E
- Published
- 2002
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8. Optimisation of chest computed tomography using a phantom: impact of mAs and reconstruction techniques on image quality
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Reis, Cláudia, Faqir, T., Harsaker, V., Hogg, Peter, Kristoffersen, L., van Rein, I. L., Stancombe, K., Warmerdam, N. C., and Wergeland, C.
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Lungs CT ,Imagiology ,mAs ,Phantom ,Chest ,Image quality ,Optimisation ,Computed tomography ,Reconstruction techniques - Abstract
Objectives: To verify if the mAs and reconstruction techniques affect the visualisation of relevant structures in lung Computed Tomography (CT) using a phantom. Methods: Images were acquired using various mAs and reconstruction techniques. Image quality (IQ) was analysed applying two approaches: perceptual, using 5 observers and objective (edge gradient calculation) to verify the sharpness of the structures. Dose was recorded. Wilcoxon Signed Rank test was used to compare the data from the perceptual image analysis. P-values were calculated (Bonferroni-Correction method) to compare reconstruction techniques and mAs. A Kappa Test with linear weighting was performed to calculate the level of agreement between observers. Results: The Wilcoxon-Signed-Rank-Test showed no significant difference between the reconstruction techniques tested (p
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- 2016
9. Molecular population divergence and sexual selection on morphology in the banded demoiselle (Calopteryx splendens)
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Svensson, E. I., Kristoffersen, L., Oskarsson, K., and Bensch, S.
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Morphological variation -- Research ,Sexual selection in animals -- Research ,Damselfish -- Research ,Biological sciences - Abstract
Molecular population divergence revealed by amplified fragment length polymorphism analysis was investigated. Observations suggested that molecular population divergence was highly significant among the Northern European populations.
- Published
- 2004
10. The impact of a population-based multi-factorial lifestyle intervention on changes in long-term dietary habits The Inter99 study
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Toft, U., Kristoffersen, L., Ladelund, S., Ovesen, L., Lau, C., Borch-Johnsen, K., Pisinger, Charlotta, Jørgensen, Torben, Toft, U., Kristoffersen, L., Ladelund, S., Ovesen, L., Lau, C., Borch-Johnsen, K., Pisinger, Charlotta, and Jørgensen, Torben
- Abstract
Udgivelsesdato: 2008-Jun-4, OBJECTIVE: To evaluate the effectiveness of a population-based multi-factorial lifestyle intervention on long-term changes in dietary habits compared to a non-intervention control group. METHODS: The study was a randomized controlled lifestyle intervention study, Inter99 (1999-2006), Copenhagen, Denmark, using a high-risk strategy. Participants in the intervention group (n=6 091) had at baseline a medical health-examination and a face-to-face lifestyle counselling. Individuals at high risk of ischemic heart disease were repeatedly offered both individual and group-based counselling. The control group (n=3 324) was followed by questionnaires. Dietary habits were measured by a validated 48-item food frequency questionnaire and changes were analyzed by multilevel analyses. RESULTS: At the 5-year follow-up the intervention group compared to the control group had significantly increased their intake of vegetables (men: net-change: 23 g/week; p=0.04; women: net-change: 27 g/week; p=0.005) and decreased the intake of highly saturated fats used on bread and for cooking (men: OR=0.59 (0.41-0.86); women: OR=0.42 (0.30-0.59)). Significant effects on fruit and fish intake were found at the 3-year follow-up but the effect attenuated at the 5-year follow-up. CONCLUSION: A population-based multi-factorial lifestyle intervention promoted significant greater beneficial long-term dietary changes compared to the control group, especially the intake of vegetables and saturated fat was improved.
- Published
- 2008
11. The Dietary Quality Score:validation and association with cardiovascular risk factors: the Inter99 study
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Toft, U, Kristoffersen, L H, Lau, C, Borch-Johnsen, K, Jørgensen, T, Toft, U, Kristoffersen, L H, Lau, C, Borch-Johnsen, K, and Jørgensen, T
- Abstract
OBJECTIVE: To develop and assess the validity of the Dietary Quality Score (DQS) and investigate the association with cardiovascular risk factors.DESIGN: Cross-sectional population-based study.SETTING: Copenhagen County, Glostrup, Denmark.SUBJECTS: A random sample of 12,934 men and women aged 30-60 years were invited to a health examination. A total of 6542 participants were included in the statistical analysis.METHODS: The DQS was developed using eight questions from a 48-item food frequency questionnaire (FFQ) and validated using a 198-item FFQ. Associations between the DQS and fasting serum lipids, homocysteine, blood pressure and the absolute risk of ischaemic heart disease (IHD) were explored.RESULTS: A higher DQS was shown to be associated with higher dietary quality in general, including a low intake of fat, especially saturated fat; a high intake of fibre; various vitamins and minerals; and fruit, fish, vegetables and whole-grain products. A higher score according to the DQS was significantly negatively associated with total cholesterol (P=0.0031), triglyceride (P=0.0406), low-density lipoprotein-cholesterol (P=0.0071), homocysteine (P<0.0001) and the absolute risk of IHD (P<0.0001), adjusted for sex, age, smoking habits and physical activity level.CONCLUSIONS: The DQS is a simple, valid and quick tool to make a rough classification of individuals into groups with high, average and low dietary quality. The DQS is negatively associated with serum lipids, homocysteine and the absolute risk of IHD.SPONSORSHIP: The Inter99 study is supported economically by The Danish Medical Research Council, The Danish Centre for Evaluation and Health Technology Assessment, Novo Nordisk, Copenhagen County, The Danish Heart Foundation, The Danish Pharmaceutical Association, Augustinus Foundation, Ib Henriksen Foundation and Becket Foundation, Copenhagen County.
- Published
- 2007
12. Aglomerular Hemipteran Antennal Lobes--Basic Neuroanatomy of a Small Nose
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Kristoffersen, L., primary, Hansson, B. S., additional, Anderbrant, O., additional, and Larsson, M. C., additional
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- 2008
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13. Drug Screening of Hair by Liquid Chromatography-Tandem Mass Spectrometry
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Hegstad, S., primary, Khiabani, H. Z., additional, Kristoffersen, L., additional, Kunoe, N., additional, Lobmaier, P. P., additional, and Christophersen, A. S., additional
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- 2008
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14. Conditionals in the layered structure of FG
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Wakker, Gerrigje, Fortescue, M., Harder, P., and Kristoffersen, L.
- Published
- 1992
15. NNP06 Non-nutritive sucking in the high-risk preterm infant
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Hafstrom, M., primary, Kristoffersen, L., additional, Grunewald, K., additional, and Rygg, M., additional
- Published
- 2007
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16. Relative validity of a food frequency questionnaire used in the Inter99 study
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Toft, U, primary, Kristoffersen, L, additional, Ladelund, S, additional, Bysted, A, additional, Jakobsen, J, additional, Lau, C, additional, Jørgensen, T, additional, Borch-Johnsen, K, additional, and Ovesen, L, additional
- Published
- 2007
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17. Carrot psyllid (Trioza apicalis) winter habitats – insights in shelter plant preference and migratory capacity
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Kristoffersen, L., primary and Anderbrant, O., additional
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- 2007
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18. Diet and exercise intervention in a general population mediators of participation and adherence: the Inter99 study
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Toft, U. N., primary, Kristoffersen, L. H., additional, Aadahl, M., additional, von Huth Smith, L., additional, Pisinger, C., additional, and Jorgensen, T., additional
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- 2006
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19. The Dietary Quality Score: validation and association with cardiovascular risk factors: the Inter99 study
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Toft, U, primary, Kristoffersen, L H, additional, Lau, C, additional, Borch-Johnsen, K, additional, and Jørgensen, T, additional
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- 2006
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20. Simultaneous determination of citalopram, fluoxetine, paroxetine and their metabolites in plasma and whole blood by high-performance liquid chromatography with ultraviolet and fluorescence detection
- Author
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Kristoffersen, L, primary, Bugge, A, additional, Lundanes, E, additional, and Slørdal, L, additional
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- 1999
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21. The impact of a population-based multi-factorial lifestyle intervention on alcohol intake: the Inter99 study.
- Author
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Toft U, Pisinger C, Aadahl M, Lau C, Linneberg A, Ladelund S, Kristoffersen L, and Jørgensen T
- Abstract
PURPOSE: To investigate the effect of screening and five years of multi-factorial lifestyle intervention on changes in alcohol intake in a general population. METHODS: The study was a pre-randomized intervention study on lifestyle, Inter99 (1999-2006), Copenhagen, Denmark. Participants in the intervention group (n=6 091) had at baseline a medical health examination and a face-to-face lifestyle counselling. Individuals at high risk of ischemic heart disease were repeatedly offered both individual and group-based counselling. The control group (n=3 324) was followed by questionnaires. Alcohol intake was measured by questionnaires. Changes were analysed by multilevel analyses. RESULTS: Binge drinking decreased both in men and women at three and five-year follow-ups (men: five-year: net-change:-0.13; p=0.03; women: five-year: net-change:-0.08; p=0.04). Furthermore, in women the ratio between wine and total alcohol was increased compared with the control group at five-year follow-up (net-change: 0.04; p<0.01). In men with a high intake of alcohol (>21 drinks per week) the effect on total alcohol intake was maintained at five-year follow-up (net-change: -3.7; p=0.01). No significant effects were found in women on total alcohol intake. CONCLUSION: Multi-factorial lifestyle intervention, including low intensity alcohol intervention, improved long-term alcohol habits in a general population.Copyright © 2009 by Elsevier Inc. [ABSTRACT FROM AUTHOR]
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- 2009
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22. Driving under the influence of zopiclone: Elimination between two consecutive blood samples.
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Strand MC, Bleka Ø, Kristoffersen L, and Høiseth G
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- Humans, Tandem Mass Spectrometry, Bayes Theorem, Hypnotics and Sedatives, Substance Abuse Detection, Driving Under the Influence, Automobile Driving
- Abstract
Aim: Zopiclone is a widely used hypnotic drug which is frequently detected in apprehended drivers. For assessments in forensic cases, the elimination half-life (t
1/2 ) of a drug is sometimes important. A t1/2 of 3.5-6.5 h for zopiclone is previously reported in healthy individuals, but different factors like age and drug-interactions can affect the t1/2 of zopiclone. The aim of this study was to describe concentrations of zopiclone and co-ingestion of additional drugs in apprehended drivers, and to investigate the t1/2 of zopiclone based on two consecutive blood samples., Methods: Data was collected from apprehended drivers in Norway between 2003 and 2021. All cases where zopiclone was detected were included. In a subset of the material, two consecutive whole blood samples were collected ≥ 20 and < 60 min apart. Concentrations of zopiclone in blood were determined by LC-MS or UHPLC-MS/MS. The elimination and t1/2 of zopiclone was estimated from the concentration change of zopiclone and the time interval between the two consecutive blood samples, under the assumption of first order kinetics., Results: The median concentration among all zopiclone positive cases was 0.044 mg/L (IQR 0.070 mg/L) (n = 2401). The most frequent additional drugs detected were ethanol (36%), diazepam (22%), amphetamine (14%) and THC (14%). In zopiclone-only cases (n = 364), the median concentration of zopiclone was 0.066 mg/L (IQR 0.115 mg/L). In 112 cases, two consecutive blood samples were collected. Of these, 28 cases showed increasing concentrations of zopiclone between the two sampling time points. Among the cases in which the concentration decreased (n = 84), the median C1 was 0.048 mg/L (IQR 0.062 mg/L) and the median C2 was 0.043 mg/L (IQR 0.056 mg/L). A Bayesian statistical model was used to obtain the posterior distribution of t1/2 . The posterior median of t1/2 was estimated to 3.1 h (IQR=0.39 h) when including only the cases showing decreasing concentrations, and this increased to 3.8 h (IQR=0.52 h) when also including samples showing non outlying increase in concentrations. There was no statistically significant gender difference in the calculated half-lives (two-sided Mann-Whitney U test, p = .525)., Conclusions: This study showed that zopiclone is frequently detected in apprehended drivers in supra therapeutic concentrations and poly drug cases. The elimination of zopiclone in blood from two consecutive blood samples indicated an apparent t1/2 of between 3.1 and 3.8 h, which is within the lower range of what previous experimental studies on healthy individuals have reported., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)- Published
- 2023
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23. Comparative Evaluation of Carboxyhemoglobin Quantification in Postmortem Whole Blood by CO-Oximetry and Headspace Gas Chromatography with Flame Ionization Detection and Atom Absorption Spectrophotometry.
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Kristoffersen L, Vevelstad M, Hansen IA, Strømsvåg B, and Strand DH
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- Male, Humans, Flame Ionization, Chromatography, Gas, Spectrophotometry, Atomic, Carboxyhemoglobin analysis, Oximetry methods
- Abstract
A comparative evaluation of two methods used for carboxyhemoglobin (COHb) determination in postmortem whole blood was performed: carbon monoxide (CO)-oximetry measuring at 128 wavelengths and headspace gas chromatography with flame ionization detection (HS-GC--FID) where CO was determined after catalytic reduction of CO to CH4 and Fe was determined by atom absorption spectrophotometry (AAS, 248.3 nm). An aliquot of 100 µL whole blood was loaded into the CO-oximetry module. In the HS-GC--FID analysis, to 1.0 mL of whole blood, 3.0 mL of saponin solution was added, mixed and centrifuged. To 20 mL HS vials, 400 µL of the supernatant was added and the vials were immediately sealed. One milliliter of potassium hexacyanoferrat (III) solution was added through the HS septum and mixed. The samples were incubated at 70°C for 5 min. CO was separated using He as carrier gas and a CP-Molsieve 5 Å PLOT capillary column. Fe was determined using 400 µL of the saponin supernatant diluted to 10 mL by water. During a period of ∼3 years, 124 postmortem whole blood samples were analyzed. Bland-Altman method comparison showed satisfactory agreement and no significant bias between the methods for the whole saturation range (5 to 85% COHb). Five samples, all with %COHb >40, showed deviations of more than 10% COHb in absolute terms. One sample, in the lower COHb range <10%, was false negative on the CO-oximetry method. The between-assay accuracy, reported as bias, at 60% COHb was -0.8% and -9.0%, and precision, reported as relative standard deviation, was 1.6% and 7.7%, for the CO-oximetry and HS-GC--FID-AAS methods, respectively. Both methods obtained satisfactory results in proficiency testing rounds, with z-scores <±2 (n = 11). This study showed that the CO-oximetry method based on the 128-wavelength principle and the HS-GC--FID-AAS method are comparable and satisfactory for %COHb determination in postmortem whole blood., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2023
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24. Skin-to-skin contact in the delivery room for very preterm infants: a randomised clinical trial.
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Kristoffersen L, Bergseng H, Engesland H, Bagstevold A, Aker K, and Støen R
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- Infant, Newborn, Humans, Male, Female, Pregnancy, Birth Weight, Delivery Rooms, Infant, Very Low Birth Weight, Infant, Premature psychology, Cesarean Section
- Abstract
Objective: Evaluating safety, feasibility and effects on physiological parameters of skin-to-skin contact (SSC) from birth between mothers and very preterm infants in a high-income setting., Design: Open-label randomised controlled trial., Setting: Three Norwegian neonatal units., Patients: Preterm infants at gestational age (GA) 28
0 -316 weeks and birth weight >1000g delivered vaginally or by caesarean section (C-section)., Intervention: Two hours of early SSC between the mother and the infant compared to standard care (SC) where the infant is separated from the mother and transferred to the neonatal unit in an incubator., Results: 108 infants (63% male, 57% C-section, mean (SD) GA 30.3 weeks (1.3) and birth weight 1437 g (260)) were included. Median (IQR) age at randomisation was 23 min (17-30). During the first 2 hours after randomisation, 4% (2 of 51) and 7% (4 of 57) were hypothermic (<36.0°C) in the SSC and SC group, respectively (p=0.68, OR 0.5, 95% CI 0.1 to 3.1). Significantly fewer infants in the SSC group had hyperthermia (>37.5°C) (26% (13 of 57) vs 47% (27 of 51), respectively, p=0.02, OR 0.4, 95% CI 0.2 to 0.9). No infant needed mechanical ventilation within the first 2 hours. Median (IQR) duration of SSC was 120 (80-120) min in the intervention group. There was no difference in heart rate, respiratory rate and oxygen saturation between groups during the first 24 hours., Conclusion: This study from a high-income setting confirmed that SSC from birth for very preterm infants was safe and feasible. Physiological parameters were not affected by the intervention. The long-term effects on neurodevelopment, maternal-infant bonding and maternal mental health will be collected., Trial Registration Number: NCT02024854., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)- Published
- 2023
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25. Postpartum Experiences of Early Skin-to-Skin Contact and the Traditional Separation Approach After a Very Preterm Birth: A Qualitative Study Among Mothers.
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Føreland AM, Engesland H, Kristoffersen L, and Fegran L
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Traditional care immediately after very preterm birth separates the mother and child by the transfer of the infant to the neonatal intensive care unit. A nonseparation approach is currently being considered, allowing early skin-to-skin contact in the delivery room/postoperative care unit. This study aimed to explore mothers' experiences of early skin-to-skin contact and traditional care. A qualitative study using individual semi-structured interviews with five mothers from each of the two groups was conducted. Content analysis revealed that both groups' experiences were characterized by (i) mothers' need to be affirmed of their infants' vitality, (ii) bonding challenges, and (iii) benefits of skin-to-skin contact. We suggest that early skin-to-skin contact after very preterm births is crucial for the bonding process and mothers' feelings of safety and well-being. When early skin-to-skin contact is infeasible, our findings reveal the significance of photos, information, and the father's presence at the time of postpartum separation., Competing Interests: Declaration of Conflicting Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© 2022 The Author(s).)
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- 2022
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26. Frequency of postmortem ethanol formation in blood, urine and vitreous humor - Improving diagnostic accuracy with the use of ethylsulphate and putrefactive alcohols.
- Author
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Oshaug K, Kronstrand R, Kugelberg FC, Kristoffersen L, Mørland J, and Høiseth G
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- Autopsy, Ethanol, Humans, Postmortem Changes, Body Fluids, Vitreous Body
- Abstract
Purpose: This study aimed to compare the frequency of postmortem ethanol formation in blood, urine and vitreous humor according to negative ethylsulphate (EtS) in blood or positive putrefactive alcohols (PA's) in either medium. Furthermore, it aimed to evaluate the interpretational value of calculated ethanol ratios in relation to EtS and PA results., Methods: Blood ethanol positive forensic cases were included; one dataset consisting of 2504 cases with EtS analysed in blood and another dataset with 8001 cases where PA's were analysed., Results: PA's were found in 24.4% of cases. EtS was negative in 15.3%, 9.4% and 7.4% of cases that were positive for ethanol in blood, urine and vitreous humor, respectively. In EtS negative cases, the concentrations of ethanol in blood, urine and vitreous humor were lower than 0.20 g/kg in 51.3%, 67.4% and 77.8%, respectively. It was 1.0 g/kg or higher in blood in 4.2% of cases. More EtS negative and PA positive cases were seen in central compared to peripheral blood. Ethanol ratios between urine or vitreous humor and blood were significantly lower in both EtS negative and PA positive cases, but large variations were observed., Conclusion: EtS and PA analysis improve the diagnostic accuracy of ethanol in postmortem cases. Postmortem ethanol formation in vitreous humor and urine were both more frequent than expected and we recommend the analysis of ethanol primarily in peripheral blood if available., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)
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- 2022
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27. Quantitative Determination of Ethyl Glucuronide and Ethyl Sulfate in Postmortem and Antemortem Whole Blood Using Phospholipid Removal 96-Well Plate and UHPLC-MS-MS.
- Author
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Sidqey D, Liane VH, and Kristoffersen L
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- Chromatography, High Pressure Liquid, Glucuronates, Sulfuric Acid Esters, Phospholipids, Tandem Mass Spectrometry
- Abstract
Postmortem ethanol formation is a well-known problem in forensic toxicology. Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are ethanol metabolites that can be used to distinguish antemortem alcohol intake from postmortem formation of ethanol and in addition can be a helpful tool in assessment of the hip-flask defense. To an aliquot of 100 µL whole blood, internal standard (IS) and water was added before protein precipitation treatment (PPT) with ice-cold acetonitrile (ACN). The supernatants were filtered through a 96-well phospholipid removal plate, evaporated to dryness and reconstituted in 150 µL water/ACN/formic acid (FA). Identification of compounds was performed using multiple reaction monitoring (MRM) in negative mode. Gradient elution was performed on a C18 column with methanol (MeOH) and 0.1% FA. The run time was 4.5 min, and 0.5 µL was injected on an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS) instrument. Linearity was achieved (coefficient of determination (R2) ≥ 0.999) for EtG in the range of 0.089 to 22 mg/L (0.40-100 µM) and EtS 0.025 to 6.3 mg/L (0.20-50 µM). The limit of quantification (LOQ) was 0.067 mg/L (0.30 µM) for EtG and 0.019 mg/L (0.15 µM) for EtS. Between assay accuracy was -15% to 8% and precision reported as relative standard deviation (RSD) was ≤ 4.5%. Precision, estimated as the RSD of the concentration difference between results from two independent analyses of authentic whole blood samples, was ≤ 6.7%. Recovery was ≥ 61% for EtG and ≥ 77% for EtS and matrix effects (ME) were 99% to 103%. Method comparison was carried out with a previously used UHPLC-MS-MS method, and satisfactory agreement was achieved, and external proficiency testing control samples had z-score < ± 1. The method has been used in routine work for more than 4 years analyzing about 6,000 antemortem and postmortem whole blood samples and has proven to be robust and reliable., (© The Author(s) 2020. Published by Oxford University Press.)
- Published
- 2021
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28. Relationship between betahydroxybutyrate (BHB) and acetone concentrations in postmortem blood and cause of death.
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Midtlyng L, Høiseth G, Luytkis H, Kristoffersen L, Le Nygaard I, Strand MC, Arnestad M, and Vevelstad M
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- Adult, Aged, Aged, 80 and over, Biomarkers blood, Cause of Death, Female, Humans, Male, Middle Aged, Norway epidemiology, Registries, Young Adult, 3-Hydroxybutyric Acid blood, Acetone blood, Alcohol-Induced Disorders mortality, Diabetes Complications mortality
- Abstract
Unexpected death caused by diabetic or alcoholic ketoacidosis is easily overlooked due to the non-specific symptoms. Although the acid betahydroxybutyrate (BHB) is the most abundant ketone body formed in conditions with ketoacidosis, routine analysis in postmortem investigations often only includes the neutral ketone body acetone. This study aims to evaluate the usefulness of implementing routine BHB analysis in postmortem cases, by investigating the relationship between BHB and acetone concentrations in postmortem blood and the main cause of death. From our database of forensic autopsy cases examined from 2012 to 2015, there were 376 cases with BHB and/or acetone detected in postmortem blood that could be paired with data from the Norwegian Cause of Death Registry. Cases were categorized into three groups based on cause of death: "Diabetes-related" (n = 38), "Alcohol-related" (n = 35) and "Other" (n = 303). Analysis of BHB in blood was performed using UHPLC-MS/MS (limit of quantification (LOQ) 52 mg/L) and of acetone using HS-GC-FID (LOQ 87 mg/L). For the purpose of the study, the acetone method was also validated for a LOQ of 23 mg/L. The median BHB concentration was significantly higher in the group of diabetes-related deaths (671 mg/L, range 68-1311 mg/L) compared to the group of alcohol-related (304 mg/L, range 65-1555 mg/L, p <0.001) and other causes of deaths (113 mg/L, range 0-1402 mg/L, p <0.001). In seven deaths (1.9%), the BHB blood concentration was above the suggested pathological threshold of 250 mg/L, without detection of acetone in blood above 23 mg/L. In 15% of deaths by other causes than diabetes or alcohol, a pathologically significant BHB blood concentration was detected. Our results indicate that BHB is a more reliable marker of pathologically significant ketoacidosis than acetone, and we suggest that BHB should be routinely analyzed in postmortem investigations., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021 Elsevier B.V. All rights reserved.)
- Published
- 2021
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29. Skin-to-skin contact during eye examination did not reduce pain compared to standard care with parental support in preterm infants.
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Kristoffersen L, Støen R, Bergseng H, Follestad T, Theodorsson E, Vederhus B, Adde L, and Austeng D
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- Cross-Over Studies, Female, Humans, Infant, Newborn, Infant, Premature, Male, Pain, Procedural etiology, Kangaroo-Mother Care Method, Neonatal Screening adverse effects, Pain, Procedural prevention & control, Retinopathy of Prematurity diagnosis
- Abstract
Aim: We compared the pain relieving effect of skin-to-skin contact versus standard care in the incubator during screening for retinopathy of prematurity., Methods: This randomised crossover study included 35 preterm infants of less than 32 weeks of gestational age admitted to St Olavs University Hospital, Trondheim, Norway, between January 2014 and June 2016. Randomisation was for skin-to-skin with one of the parents or standard care with supportive positioning by parents for the first of two consecutive eye examinations. The pain score was measured twice using the Premature Infant Pain Profile (PIPP) during and after the eye examination. The infants' movement activity was video recorded after the examination., Results: There was no difference in mean pain scores with skin-to-skin contact versus standard care during (10.2 vs. 10.3, p = 0.91) or after (7.0 vs. 6.8, p = 0.76) the procedure. Independent of the randomisation group, PIPP scores were lower than previous comparable studies have found. Bouts of movement activity were also the same whether the examination was conducted in skin-to-skin position or in the incubator (p = 0.91)., Conclusion: Skin-to-skin contact during the eye examination did not provide additional pain relief compared to standard care where the parents were already a part of the multidimensional approach., (©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)
- Published
- 2019
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30. Randomised controlled trial showed that neonates received better pain relief from a higher dose of sucrose during venepuncture.
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Kristoffersen L, Malahleha M, Duze Z, Tegnander E, Kapongo N, Støen R, Follestad T, Eik-Nes SH, and Bergseng H
- Subjects
- Cross-Over Studies, Humans, Infant, Newborn, Pain Measurement, Pain Management methods, Phlebotomy adverse effects, Sucrose administration & dosage, Sweetening Agents administration & dosage
- Abstract
Aim: We compared the effect of two different doses of sucrose on neonatal pain scores during venepuncture., Methods: This randomised crossover study focused on neonates born weighing more than 1000 g from December 2014 to June 2016, who received neonatal intensive care at two hospitals: one in Empangeni, South Africa, and one in Trondheim, Norway. During two consecutive venepuncture procedures, 27 neonates from South Africa and 26 neonates from Norway were randomised to receive 0.2 mL or 0.5 mL sucrose. Half was administered two minutes before venepuncture and the rest immediately before the procedure. South Africa used 25% sucrose and Norway 24%. Pain scores were measured twice using the Premature Infant Pain Profile-Revised: during skin puncture and after the needle was removed., Results: The mean pain scores during skin puncture were significantly lower with 0.5 mL sucrose than with 0.2 mL (5.3 versus 6.8, p=0.008), but the mean pain scores after the needle was removed were similar with both doses (4.7 versus 5.4, p=0.29). We found no significant association between weight and pain scores., Conclusion: We showed that neonates received better pain relief from 0.5 mL than 0.2 mL sucrose during venepuncture but not after the needle was removed., (©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)
- Published
- 2018
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31. Comparative Study of Postmortem Concentrations of Antidepressants in Several Different Matrices.
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Øiestad ÅML, Karinen R, Rogde S, Nilsen S, Boye Eldor KB, Brochmann GW, Arnestad M, Øiestad EL, Peres MD, Kristoffersen L, and Vindenes V
- Subjects
- Antidepressive Agents blood, Autopsy, Forensic Toxicology methods, Humans, Postmortem Changes, Substance Abuse Detection methods, Antidepressive Agents analysis, Muscle, Skeletal chemistry, Pericardial Fluid chemistry, Vitreous Body chemistry
- Abstract
Peripheral blood (PB) is considered to be the golden standard for measuring postmortem drug concentrations. In several cases, PB is however not available, but information regarding drug findings might still be crucial in order to determine the cause of death. Antidepressants are frequently detected in postmortem samples from forensic toxicology cases, but the literature investigating concentrations in other matrices than peripheral and heart blood is limited.We here describe a study for comparison of concentrations for a large number of different drugs in six different matrices. A total of 173 postmortem cases were included in the study material. The results from 44 cases with findings of antidepressants (amitriptyline/nortriptyline, citalopram, mianserin, mirtazapine, paroxetine, sertraline, trimipramine and venlafaxine) are presented in this article. Concentrations in peripheral and cardiac blood (CB), pericardial fluid (PF), two muscle samples and vitreous humour (VH) are compared. Ratios between concentrations in different matrices have also been compiled from available literature.All the investigated antidepressants were detected in all different matrices, and comparable concentration levels were found in the different matrices with a few exceptions. Concentrations in VH were generally lower than in the other matrices, and in a few cases with low concentrations in blood the antidepressants were not detected in VH. For most of the cases, ratios of 0.5-2 were found between concentration in PB and that in the other matrices. Some deviant concentrations where however found.This study shows that CB, PF, muscle and VH can provide important indications of the corresponding concentrations in PB when PB is not available.
- Published
- 2018
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32. EtG and EtS in Autopsy Blood Samples With and Without Putrefaction Using UPLC-MS-MS.
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Hegstad S, Kristoffersen L, Liane VH, and Spigset O
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- Autopsy, Calibration, Forensic Toxicology instrumentation, Humans, Limit of Detection, Reproducibility of Results, Chromatography, Liquid methods, Forensic Toxicology methods, Glucuronates blood, Postmortem Changes, Sulfuric Acid Esters blood, Tandem Mass Spectrometry methods
- Abstract
Analytical challenges related to postmortem specimens are well known. The degree of putrefaction of the corpse will influence the quality of the blood samples, and both the efficiency of sample preparation and the subsequent chromatographic performance can be affected. An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method was developed and validated for the determination of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in postmortem whole blood. Sample preparation prior to UPLC-MS-MS analysis consisted of protein precipitation and filtration through a phospholipid removal plate. Chromatography was achieved using an HSS T3 column and gradient elution with formic acid in water in combination with methanol. The injection volume was 0.5 µL. Negative electrospray ionization was performed in the multiple reaction monitoring mode. Two transitions were monitored for the analytes and one for the internal standards. The between-assay relative standard deviations were in the range of 1.7-7.0% and the limits of quantification were 0.025 and 0.009 mg/L for EtG and EtS, respectively. Recovery was 51-55% and matrix effects ranged from 98% to 106% (corrected with internal standard). Blood samples from nine autopsy cases with various extents of putrefaction were analyzed. The sample preparation efficiently removed the phospholipids from the blood specimens. The samples were clean and the analytical quality of the chromatographic performance was satisfactory for both analytes irrespective of the degree of putrefaction., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2017
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33. Early skin-to-skin contact or incubator for very preterm infants: study protocol for a randomized controlled trial.
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Kristoffersen L, Støen R, Rygh H, Sognnæs M, Follestad T, Mohn HS, Nissen I, and Bergseng H
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- Birth Weight, Checklist, Child Development, Child, Preschool, Clinical Protocols, Gestational Age, Humans, Infant, Infant, Newborn, Infant, Very Low Birth Weight psychology, Intensive Care Units, Neonatal, Mother-Child Relations, Norway, Object Attachment, Research Design, Time Factors, Workflow, Incubators, Infant, Infant, Low Birth Weight psychology, Infant, Premature psychology, Kangaroo-Mother Care Method, Skin Physiological Phenomena
- Abstract
Background: Skin-to-skin care immediately following delivery is a common practice for term infants and has been shown to improve cardiorespiratory stability, facilitate early bonding, and promote breastfeeding. Since 2007, the use of skin-to-skin care has been practiced for preterm infants from 32 weeks of gestation in the delivery room at St. Olav's University Hospital. In the present study we aim to investigate whether skin-to-skin care following delivery is safe, and how it affects early and late outcomes compared to standard care for very preterm infants., Methods/design: A randomized controlled trial (RCT) of skin-to-skin care in the delivery room for very preterm infants born at gestational age 28
0 -316 weeks with birth weight >1000 grams. Infants with severe congenital malformations or need of intubation in the delivery room are excluded. A detailed checklist and a flowchart were prepared for the study, and all involved professionals (neonatologists, neonatal nurses, obstetricians, anesthesiologists, midwives) participated in medical simulation training prior to study start on February 1, 2014. A consultant in neonatology and a neonatal nurse are present at all deliveries. Infants with birth weight <1500 grams receive an intravenous line with glucose, amino acids, and caffeine citrate in the delivery room. Infants with gestational age <30 weeks are routinely put on continuous positive airway pressure (CPAP). After initial stabilization, infants are randomized to skin-to-skin care or are transferred to the nursery in an incubator. Primary outcome is cognitive development at 2 years measured with the Bayley Scales of Infant Development, Third Edition. Secondary outcomes are safety defined as hypothermia, respiratory failure, and/or cardiopulmonary resuscitation, physiological stability after birth and motor, language and cognitive development at 1 year for the child, and mental health measured with the State-Trait Anxiety Inventory (STAI) at discharge, and at 3 months and 2 years after expected date of delivery for the mothers., Discussion: The study may have important implications for the initial care for very preterm infants after delivery and increase our understanding of how early skin-to-skin care affects preterm infants and their mothers., Trial Registration: ClinicalTrials, NCT02024854 . Registered on 19 December 2013.- Published
- 2016
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34. Ethanol elimination rates at low concentrations based on two consecutive blood samples.
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Høiseth G, Wiik E, Kristoffersen L, and Mørland J
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- Alcoholic Intoxication blood, Alcoholic Intoxication metabolism, Chromatography, Gas, Female, Humans, Male, Blood Alcohol Content, Driving Under the Influence, Ethanol metabolism, Metabolism
- Abstract
Introduction: For ethanol, the elimination curve change from apparent zero to apparent first order kinetics at low blood alcohol concentrations (BACs). This is less studied than elimination at higher BACs, and knowledge about this low BAC elimination is especially missing in drunk drivers representing a population with a high frequency of heavy drinkers with increased rate of ethanol metabolism. The aim of this study was to investigate the point at which elimination rates turns from zero to first order kinetics and the exact elimination rates at the very low BAC intervals in drunk drivers., Methods: Two consecutively collected samples from suspected drunk drivers were used. All samples were analyzed by two headspace gas chromatography flame ionization detector methods (limit of quantification=0.04g/kg). The elimination rates at BACs below 0.25g/kg (study group, n=175) was studied in detail, and compared to the elimination rates in a moderate BAC reference group (n=789) as well as a high BAC reference group (n=4435)., Results: There were no differences in age, gender and drivings occurring during night-time between the study group and the reference groups. The mean elimination rates were stable at 0.18-0.19g/kg/h from a BAC of 4.0g/kg and until BAC in the first blood sample fell below 0.19g/kg. At BACs below 0.19g/kg, the mean elimination rate gradually declined from 0.163g/kg/h to the lowest elimination rate of 0.083g/kg/h. There was no relation between the concentration of ethanol and elimination rate at BACs above 0.19g/kg (Pearson's r=0.035, p=0.3), but there was a strong relation between concentration of ethanol and elimination rate at BACs below 0.19g/kg (Pearson's r=0.56, p<0.001)., Conclusion: In conclusion, the present study showed that in a population of drunk drivers, the shift from zero order to first order kinetics occurs when BAC falls below 0.19g/kg. Below this points, the present study indicate that drunk drivers show elimination rates comparable to the normal population. These results could assist in back-calculations in cases of drunk driving involving low BACs., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2016
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35. Skin-to-Skin Care After Birth for Moderately Preterm Infants.
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Kristoffersen L, Stoen R, Hansen LF, Wilhelmsen J, and Bergseng H
- Subjects
- Female, Gestational Age, Humans, Infant, Infant, Newborn, Intensive Care Units, Neonatal, Male, Pregnancy, Prospective Studies, Skin Care, Infant, Premature, Kangaroo-Mother Care Method
- Abstract
Objective: To investigate the feasibility and safety of skin-to-skin care after birth for moderately preterm infants., Design: Prospective cohort study., Setting: The study was conducted at the maternity wards and NICUs of three study sites in Norway., Participants: Ninety preterm infants born vaginally with gestational ages of 32 weeks/0 days to 34 weeks/6 days., Methods: Comparison of groups of preterm infants who received skin-to-skin care or conventional treatment in incubators after birth., Results: Median gestational age and birth weight were similar in the two groups: 33 weeks/5 days versus 34 weeks/3 days (p = .464) and 2,100 versus 2,010 g (p = .519). There were no differences in the first body temperature (p = .841) and blood glucose level (p = .539) between the groups., Conclusion: Early skin-to-skin contact in the delivery room for moderately preterm infants may be feasible and safe., (Copyright © 2016 AWHONN, the Association of Women’s Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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36. Determination of safety margins for whole blood concentrations of alcohol and nineteen drugs in driving under the influence cases.
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Kristoffersen L, Strand DH, Liane VH, Vindenes V, Tvete IF, and Aldrin M
- Subjects
- Bayes Theorem, Chromatography, Liquid, Forensic Toxicology methods, Forensic Toxicology statistics & numerical data, Humans, Mass Spectrometry, Norway, Substance Abuse Detection methods, Substance Abuse Detection statistics & numerical data, Blood Alcohol Content, Driving Under the Influence statistics & numerical data, Ethanol blood, Forensic Toxicology standards, Illicit Drugs blood, Prescription Drug Misuse, Substance Abuse Detection standards
- Abstract
Legislative limits for driving under the influence of 20 non-alcohol drugs were introduced in Norway in February 2012. Per se limits corresponding to blood alcohol concentrations (BAC) of 0.2g/kg were established for 20 psychoactive drugs, and limits for graded sanctions corresponding to BACs of 0.5 and 1.2g/kg were determined for 13 of these drugs. This new legislation made it possible for the courts to make sentences based on the analytical results, similar to the situation for alcohol. To ensure that the reported concentration is as least as high as the true concentration, with a 99% safety level, safety margins had to be calculated for each of the substances. Diazepam, tetrahydrocannabinol (THC) and alcohol were used as model substances to establish a new model for estimating the safety margins. The model was compared with a previous used model established several years ago, by a similar yet much simpler model, and they were found to be in agreement. The measurement uncertainties depend on the standard batch used, the work list and the measurements' replicate. A Bayesian modelling approach was used to determine the parameters in the model, using a dataset of 4700 diazepam positive specimens and 5400 THC positive specimens. Different safety margins were considered for low and high concentration levels of diazepam (≤2μM (0.6mg/L) and >2μM) and THC (≤0.01μM (0.003mg/L) and >0.01μM). The safety margins were for diazepam 19.5% (≤2μM) and 34% (>2μM), for THC 19.5% (≤0.01μM) and 24.9% (>0.01μM). Concentration dependent safety margins for BAC were based on a dataset of 29500 alcohol positive specimens, and were in the range 10.4% (0.1g/kg) to 4.0% (4.0g/kg) at a 99% safety level. A simplified approach was used to establish safety margins for the compounds amphetamine, MDMA, methamphetamine, alprazolam, phenazepam, flunitrazepam, clonazepam, nitrazepam, oxazepam, buprenorphine, GHB, methadone, ketamine, cocaine, morphine, zolpidem and zopiclone. The safety margins for these drugs were in the range 34-41%., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2016
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37. Redistribution of metabolic fluxes in Chlorella protothecoides by variation of media nitrogen concentration.
- Author
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Gopalakrishnan S, Baker J, Kristoffersen L, and Betenbaugh MJ
- Abstract
In this study, the Elementary Metabolite Unit (EMU) algorithm was employed to calculate intracellular fluxes for Chlorella protothecoides using previously generated growth and mass spec data. While the flux through glycolysis remained relatively constant, the pentose phosphate pathway (PPP) flux increased from 3% to 20% of the glucose uptake during nitrogen-limited growth. The TCA cycle flux decreased from 94% to 38% during nitrogen-limited growth while the flux of acetyl-CoA into lipids increased from 58% to 109% of the glucose uptake, increasing total lipid accumulation. Phosphoenolpyruvate carboxylase (PEPCase) activity was higher during nitrogen-sufficient growth. The glyoxylate shunt was found to be partially active in both cases, indicating the nutrient nature has an impact on flux distribution. It was found that the total NADPH supply within the cell remained almost constant under both conditions. In summary, algal cells substantially reorganize their metabolism during the switch from carbon-limited (nitrogen-sufficient) to nitrogen-limited (carbon-sufficient) growth., (© 2015 The Authors.)
- Published
- 2015
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38. Implementing a care pathway for elderly patients, a comparative qualitative process evaluation in primary care.
- Author
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Røsstad T, Garåsen H, Steinsbekk A, Håland E, Kristoffersen L, and Grimsmo A
- Subjects
- Aged, Cooperative Behavior, Female, Focus Groups, Home Care Services, Humans, Male, Norway, Qualitative Research, Critical Pathways, Primary Health Care organization & administration
- Abstract
Background: In Central Norway a generic care pathway was developed in collaboration between general hospitals and primary care with the intention of implementing it into everyday practice. The care pathway targeted elderly patients who were in need of home care services after discharge from hospital. The aim of the present study was to investigate the implementation process of the care pathway by comparing the experiences of health care professionals and managers in home care services between the participating municipalities., Methods: This was a qualitative comparative process evaluation using data from individual and focus group interviews. The Normalization Process Theory, which provides a framework for understanding how a new intervention becomes part of normal practice, was applied in our analysis., Results: In all of the municipalities there were expectations that the generic care pathway would improve care coordination and quality of follow-up, but a substantial amount of work was needed to make the regular home care staff understand how to use the care pathway. Other factors of importance for successful implementation were involvement of the executive municipal management, strong managerial focus on creating engagement and commitment among all professional groups, practical facilitation of work processes, and a stable organisation without major competing priorities. At the end of the project period, the pathway was integrated in daily practice in two of the six municipalities. In these municipalities the care pathway was found to have the potential of structuring the provision of home care services and collaboration with the GPs, and serving as a management tool to effect change and improve knowledge and skills., Conclusion: The generic care pathway for elderly patients has a potential of improving follow-up in primary care by meeting professional and managerial needs for improved quality of care, as well as more efficient organisation of home care services. However, implementation of this complex intervention in full-time running organisations was demanding and required comprehensive and prolonged efforts in all levels of the organisation. Studies on implementation of such complex interventions should therefore have a long follow-up time to identify whether the intervention becomes integrated into everyday practice.
- Published
- 2015
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39. Has the intake of THC by cannabis users changed over the last decade? Evidence of increased exposure by analysis of blood THC concentrations in impaired drivers.
- Author
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Vindenes V, Strand DH, Kristoffersen L, Boix F, and Mørland J
- Subjects
- Adult, Amphetamines blood, Central Nervous System Depressants blood, Chromatography, Liquid, Ethanol blood, Forensic Toxicology, Humans, Marijuana Smoking blood, Mass Spectrometry, Norway, Substance Abuse Detection, Automobile Driving legislation & jurisprudence, Dronabinol blood, Psychotropic Drugs blood
- Abstract
The main psychoactive substance, Δ9-tetrahydrocannabinol (THC) can be present in highly variable amounts in different cannabis preparations. An increase in THC content in cannabis products has been suggested, and reported from several countries. However, it has not yet been investigated if products with high potency lead to increased human exposure, and thus to higher risk of adverse effects. In this study, we examined the mean concentrations of THC in whole blood samples from drivers apprehended in Norway in the period between 2000 and 2010 suspected of driving under the influence of drugs. Cases with only THC (n=1747) have been compared to cases with only ethanol (n=38796) or amphetamines (n=2493). The increase in mean THC concentration measured from 2000 to 2010 was from 4.0 ± 0.3 to 6.6 ± 0.4 ng/ml (58%), compared to 3% for ethanol and 16% for the amphetamines. This increase in THC concentrations was to some extent paralleled by an increase in the percentage of drivers which were judged as lightly impaired by a physician. Monitoring concentrations of drugs of abuse in blood from apprehended drivers indicated an increasing exposure to THC in Norway. If similar trends are observed globally, it should be further explored if this type of information could be used to elucidate the drug consumption patterns in a population and accordingly the consequences with regard to adverse effects of cannabis from a public health perspective., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
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40. Evaluation of flavonoids and enterolactone in overnight urine as intake biomarkers of fruits, vegetables and beverages in the Inter99 cohort study using the method of triads.
- Author
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Krogholm KS, Bysted A, Brantsæter AL, Jakobsen J, Rasmussen SE, Kristoffersen L, and Toft U
- Subjects
- 4-Butyrolactone urine, Adult, Cohort Studies, Diet, Female, Humans, Male, Middle Aged, Models, Biological, 4-Butyrolactone analogs & derivatives, Feeding Behavior, Flavonoids urine, Fruit metabolism, Lignans urine, Vegetables metabolism
- Abstract
Since collection of 24 h urine samples is very time consuming and difficult to obtain, epidemiological studies typically only obtain spot urine samples. The aim of the present study was to evaluate whether flavonoids and enterolactone in overnight urine could substitute flavonoids and enterolactone in 24 h urine as an alternative and more feasible biomarker of fruit, vegetable and beverage intake. A total of 191 individuals in the Inter99 cohort in Denmark completed the validation study. Concentrations of nine urinary flavonoid aglycones (quercetin, isorhamnetin, tamarixetin, kaempferol, hesperetin, naringenin, eriodictyol, phloretin and apigenin) and enterolactone were determined in overnight and 24 h urine samples, and their validity as biomarkers of fruit, vegetable and beverage intake was evaluated in relation to two independent reference methods (Inter99 FFQ data and plasma carotenoids) by using the method of triads. The intakes of fruit, juice, vegetables and tea reported in the FFQ were reflected by the flavonoid biomarker both in overnight and 24 h urine samples. Validity coefficients for the flavonoid biomarker in overnight urine ranged from 0·39 to 0·49, while the corresponding validity coefficients for the biomarker in 24 h urine ranged from 0·43 to 0·66. Although the validity coefficients were lower for overnight urine than for the 24 h urine flavonoid biomarker, they were still of acceptable magnitude. In conclusion, the results indicate that flavonoids and enterolactone in overnight urine samples may be used as a more feasible biomarker than 24 h urine for the assessment and validation of fruit, juice, vegetable and tea intakes in epidemiological studies.
- Published
- 2012
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41. Increased expression of the integral membrane proteins EGFR and FGFR3 in anti-apoptotic Chinese hamster ovary cell lines.
- Author
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Ohsfeldt E, Huang SH, Baycin-Hizal D, Kristoffersen L, Le TM, Li E, Hristova K, and Betenbaugh MJ
- Subjects
- Animals, Apoptosis genetics, Blotting, Western, CHO Cells, Cell Line, Cricetinae, Cricetulus, ErbB Receptors metabolism, Flow Cytometry, Receptor, Fibroblast Growth Factor, Type 3 metabolism, bcl-X Protein genetics, bcl-X Protein metabolism, ErbB Receptors genetics, Receptor, Fibroblast Growth Factor, Type 3 genetics, Up-Regulation
- Abstract
Membrane proteins such as receptor tyrosine kinases (RTKs) have a vital role in many cellular functions, making them potential targets for therapeutic research. In this study, we investigated the coexpression of the anti-apoptosis gene Bcl-x(L) with model membrane proteins as a means of increasing membrane protein expression in mammalian cells. Chinese hamster ovary (CHO) cells expressing heterologous Bcl-x(L) and wild-type CHO cells were transfected with either epidermal growth factor receptor or fibroblast growth factor receptor 3. The CHO-Bcl-x(L) cell lines showed increased expression of both RTK proteins as compared with the wild-type CHO cell lines in transient expression analysis, as detected by Western blot and flow cytometry after 15 days of antibiotic selection in stable expression pools. Increased expression was also seen in clonal isolates from the CHO-Bcl-x(L) cell lines, whereas the clonal cell line expression was minimal in wild-type CHO cell lines. Our results demonstrate that application of the anti-apoptosis gene Bcl-x(L) can increase expression of RTK proteins in CHO cells. This approach may be applied to improve stable expression of other membrane proteins in the future using mammalian cell lines with Bcl-x(L) or perhaps other anti-apoptotic genes., (Copyright © 2012 International Union of Biochemistry and Molecular Biology, Inc.)
- Published
- 2012
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42. Pain reduction on insertion of a feeding tube in preterm infants: a randomized controlled trial.
- Author
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Kristoffersen L, Skogvoll E, and Hafström M
- Subjects
- Female, Follow-Up Studies, Humans, Infant, Newborn, Male, Pain diagnosis, Pain etiology, Pain Measurement, Retrospective Studies, Treatment Outcome, Enteral Nutrition adverse effects, Infant, Premature, Pain prevention & control, Sucrose administration & dosage, Sweetening Agents administration & dosage
- Abstract
Background: Gavage feeding is required in preterm infants who cannot feed by themselves. Insertion of the feeding tube is painful, and reducing the discomfort in these patients is desirable., Objective: The aim of this study was to assess pain and discomfort during nasal insertion of a feeding tube, and to evaluate different measures for pain relief., Methods: We included 24 preterm infants with postmenstrual age 28 to 32 weeks' who were in stable condition. Each infant acted as his or her own control over a 3-week period during which the tube was changed 6 times. On these occasions, 6 different treatment combinations were given in randomized order: pacifier or no pacifier, combined with no fluid, sterile water, or 30% sucrose. Pain and discomfort were assessed by at least 2 independent and experienced observers using a pain assessment tool, the Premature Infant Pain Profile; score range: 0 to 21. In general, scores of 4 to 6 are interpreted as normal or no discomfort; ≥ 12 usually signals significant pain and distress., Results: The median Premature Infant Pain Profile score during the procedure was 9 and decreased gradually toward 4 after 5 minutes. The lowest pain score was achieved by combining a pacifier with oral sucrose. Sterile water without a pacifier gave the highest score., Conclusions: Insertion of a feeding tube in preterm infants leads to a measurable degree of pain and discomfort, according to the Premature Infant Pain Profile assessment tool. Pain relief was best achieved by combining a pacifier with 30% sucrose.
- Published
- 2011
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43. [Drug testing in hair].
- Author
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Hegstad S, Kristoffersen L, Christophersen AS, and Khiabani HZ
- Subjects
- Forensic Toxicology methods, Humans, Time Factors, Hair chemistry, Pharmaceutical Preparations analysis, Substance Abuse Detection methods
- Published
- 2009
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44. The effect of adding group-based counselling to individual lifestyle counselling on changes in dietary intake. The Inter99 study--a randomized controlled trial.
- Author
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Toft U, Kristoffersen L, Ladelund S, Ovesen L, Lau C, Pisinger C, Smith Lv, Borch-Johnsen K, and Jørgensen T
- Abstract
Background: Few studies have investigated the specific effect of single intervention components in randomized controlled trials. The purpose was to investigate the effect of adding group-based diet and exercise counselling to individual life-style counselling on long-term changes in dietary habits., Methods: The study was a randomized controlled intervention study. From a general Danish population, aged 30 to 60 years (n = 61,301), two random sample were drawn (group A, n = 11,708; group B, n = 1,308). Subjects were invited for a health screening program. Participation rate was 52.5%. All participants received individual life-style counselling. Individuals at high risk of ischemic heart disease in group A were furthermore offered group-based life-style counselling. The intervention was repeated for high-risk individuals after one and three years. At five-year follow-up all participants were invited for a health examination. High risk individuals were included in this study (n = 2 356) and changes in dietary intake were analyzed using multilevel linear regression analyses., Results: At one-year follow-up group A had significantly increased the unsaturated/saturated fat ratio compared to group B and in men a significantly greater decrease in saturated fat intake was found in group A compared to group B (net change: -1.13 E%; P = 0.003). No differences were found between group A and B at three-year follow-up. At five-year follow-up group A had significantly increased the unsaturated/saturated fat ratio (net change: 0.09; P = 0.01) and the fish intake compared to group B (net change: 5.4 g/day; P = 0.05). Further, in men a non-significant tendency of a greater decrease was found at five year follow-up in group A compared to group B (net change: -0.68 E%; P = 0.10). The intake of fibre and vegetables increased in both groups, however, no significant difference was found between the groups. No differences between groups were found for saturated fat intake in women., Conclusion: Offering group-based counselling in addition to individual counselling resulted in small, but significantly improved dietary habits at five-year follow-up and a tendency of better maintenance, compared to individual counselling alone., Trial Registration: The Inter99 study was approved by the local Ethics Committee (KA 98 155) and is registered with ClinicalTrials.gov (registration number: NCT00289237).
- Published
- 2008
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45. Functional characteristics of a tiny but specialized olfactory system: olfactory receptor neurons of carrot psyllids (Homoptera: Triozidae).
- Author
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Kristoffersen L, Larsson MC, and Anderbrant O
- Subjects
- Animals, Electrophysiology, Female, Hemiptera drug effects, Male, Olfactory Receptor Neurons drug effects, Plant Extracts chemistry, Plant Extracts pharmacology, Daucus carota parasitology, Hemiptera physiology, Olfactory Receptor Neurons physiology
- Abstract
With only approximately 50 olfactory receptor neurons (ORNs), the carrot psyllid Trioza apicalis (Homoptera: Psylloidea) may have the smallest olfactory system described in adult Neopteran insects. Using single sensillum recordings (SSR) and gas chromatograph-linked SSR, we characterized 4 olfactory sensilla forming a distinct morphological type, which together house approximately 25% of all ORNs. We recorded responses to extracts and single constituents from Daucus carota ssp. sativus, from the conifers Picea abies, Pinus sylvestris, and Juniperus communis, as well as from male and female T. apicalis. Receptor neurons were highly selective; only 9 compounds in total elicited repeatable responses, and each neuron responded to at most 3 individual compounds. Chemical profiles of carrot and conifers showed significant overlap, with 4 out of 9 electrophysiologically active compounds occurring in more than one type of extract, but a carrot-specific compound elicited the most repeated responses. We identified 4 tentative neuron classes and found a rather high degree of neuronal redundancy, with 1 neuron class present in 3 and another present in all 4 of the sensilla, respectively.
- Published
- 2008
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46. The impact of a population-based multi-factorial lifestyle intervention on changes in long-term dietary habits: the Inter99 study.
- Author
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Toft U, Kristoffersen L, Ladelund S, Ovesen L, Lau C, Borch-Johnsen K, Pisinger C, and Jørgensen T
- Subjects
- Adult, Denmark, Dietary Fats, Female, Follow-Up Studies, Fruit, Humans, Male, Middle Aged, Treatment Outcome, Vegetables, Directive Counseling, Energy Intake, Feeding Behavior, Life Style
- Abstract
Objective: To evaluate the effectiveness of a population-based multi-factorial lifestyle intervention on long-term changes in dietary habits compared to a non-intervention control group., Methods: The study was a randomized controlled lifestyle intervention study, Inter99 (1999-2006), Copenhagen, Denmark, using a high-risk strategy. Participants in the intervention group (n=6 091) had at baseline a medical health-examination and a face-to-face lifestyle counselling. Individuals at high risk of ischemic heart disease were repeatedly offered both individual and group-based counselling. The control group (n=3 324) was followed by questionnaires. Dietary habits were measured by a validated 48-item food frequency questionnaire and changes were analyzed by multilevel analyses., Results: At the 5-year follow-up the intervention group compared to the control group had significantly increased their intake of vegetables (men: net-change: 23 g/week; p=0.04; women: net-change: 27 g/week; p=0.005) and decreased the intake of highly saturated fats used on bread and for cooking (men: OR=0.59 (0.41-0.86); women: OR=0.42 (0.30-0.59)). Significant effects on fruit and fish intake were found at the 3-year follow-up but the effect attenuated at the 5-year follow-up., Conclusion: A population-based multi-factorial lifestyle intervention promoted significant greater beneficial long-term dietary changes compared to the control group, especially the intake of vegetables and saturated fat was improved.
- Published
- 2008
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47. Prevalence of alcohol and drugs among Norwegian motor vehicle drivers: a roadside survey.
- Author
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Gjerde H, Normann PT, Pettersen BS, Assum T, Aldrin M, Johansen U, Kristoffersen L, Øiestad EL, Christophersen AS, and Mørland J
- Subjects
- Adult, Aged, Humans, Middle Aged, Norway epidemiology, Prevalence, Young Adult, Alcohol Drinking epidemiology, Automobile Driving statistics & numerical data, Substance-Related Disorders epidemiology
- Abstract
The objective of the study was to determine the prevalence of alcohol, psychoactive medicinal drugs and illegal drugs among drivers in Norwegian road traffic. Drivers of motor vehicles were selected from April 2005 to April 2006 in the south-eastern part of Norway, surrounding, but not including the capital, Oslo. A stratified two-stage cluster sampling procedure was used. In the first stage, random road sites and time intervals were selected, and in the second stage, drivers were stopped by random at those sites and time intervals. Altogether about 12,000 drivers were asked to provide a sample of oral fluid (saliva) and answer a few questions. Samples of oral fluid were obtained from 88% of the drivers, of whom 30% were females and 70% males. The prevalence of each drug was estimated by a weighted average using weights adjusted for under- or over-sampling compared to traffic statistics. Alcohol or drugs were found in oral fluid samples of 4.5% of the drivers; alcohol in 0.4%, psychoactive medicinal drugs in 3.4%, and illegal drugs in 1.0%. Illegal drugs were found more frequently in samples from younger drivers, while psychoactive medicinal drugs were more frequently found in samples from older drivers. Psychoactive medicinal drugs were more prevalent among females than males, among drivers stopped on working days rather than weekends, and among those who reported annual driving distances less than 16,000 km. The drugs found most frequently were zopiclone (1.4%), benzodiazepines (1.4%), codeine (0.8%), tetrahydrocannabinol (0.6%) and amphetamines (0.3%). Two or more drugs were found in 0.6% of the samples, corresponding to 15% of the drug-positive drivers.
- Published
- 2008
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48. In vitro formation of ethanol in autopsy samples containing fluoride ions.
- Author
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Høiseth G, Kristoffersen L, Larssen B, Arnestad M, Hermansen NO, and Mørland J
- Subjects
- Adult, Clostridium isolation & purification, Diabetes Mellitus blood, Ethanol urine, Flame Ionization, Fluorides urine, Forensic Toxicology, Glucose analysis, Gram-Negative Bacteria isolation & purification, Humans, Male, Specimen Handling, Vitreous Body chemistry, Ethanol blood, Fluorides blood, Postmortem Changes
- Abstract
We present a case of a death of a diabetic man where the concentration of ethanol in post-mortem blood rose from 0.4 g/l 2 days after autopsy to 3.5 g/l 10 days after autopsy. The presence of fluoride ions in this blood sample was determined with ion chromatography and verified that fluoride ions were added to the vials. The concentrations of free fluoride, corresponding to 0.21 and 0.25% w/v potassium fluoride in blood and urine, respectively, were somewhat lower than the recommended 1% w/v. However, the amount of fluoride ions bound to calcium, proteins and other compounds in the samples is unknown. The blood sample was also subject to microbiological examination, which revealed growth of bacteria. In addition, a very high concentration of glucose was found in vitreous humour from the deceased. To determine whether the ethanol detected at the first analysis was of ante-mortem origin, ethyl glucuronide was analysed. Its absence, in the blood as well as the urine sample, strongly supported the theory that, in this case, all the ethanol detected was formed post-mortem. This case showed that ethanol may be formed in vitro at a very high concentration, despite the verified presence of fluoride ions. Possible reasons for this unusual formation of ethanol were the abundant presence of bacteria, a high level of glucose and, possibly, an insufficient amount of fluoride added to the vials.
- Published
- 2008
- Full Text
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49. Simultaneous determination of 6 beta-blockers, 3 calcium-channel antagonists, 4 angiotensin-II antagonists and 1 antiarrhythmic drug in post-mortem whole blood by automated solid phase extraction and liquid chromatography mass spectrometry. Method development and robustness testing by experimental design.
- Author
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Kristoffersen L, Øiestad EL, Opdal MS, Krogh M, Lundanes E, and Christophersen AS
- Subjects
- Automation, Humans, Postmortem Changes, Reproducibility of Results, Adrenergic beta-Antagonists blood, Angiotensin Receptor Antagonists, Anti-Arrhythmia Agents blood, Chromatography, High Pressure Liquid methods, Spectrometry, Mass, Electrospray Ionization methods
- Abstract
A method for the simultaneous determination of the beta-blockers atenolol, sotalol, metoprolol, bisoprolol, propranolol and carvedilol, the calcium-channel antagonists diltiazem, amlodipine and verapamil, the angiotensin-II antagonists losartan, irbesartan, valsartan and telmisartan, and the antiarrhythmic drug flecainide, in whole blood samples from forensic autopsies was developed. Sample clean-up was achieved by precipitation and solid phase extraction (SPE) with a mixed-mode column. Quantification was performed by reversed phase high performance liquid chromatography with positive electrospray ionization mass spectrometric detection (HPLC-MS). The method has been developed and robustness tested by systematically searching for satisfactory conditions using experimental designs including factorial and response surface designs. With the exception of amlodipine, the concentration limit of quantification (cLOQ) covered low therapeutic concentration levels for all the compounds. Within assay precisions and accuracies (bias) were 3.4-21% RSD and from -24 to 21% for the concentration range 1.00-5.00 microM, respectively. Between assay precisions were 4.4-28% RSD for the concentration range from 0.1 to 5 microM and recoveries varied from 9 to 103%. The method is used for determination of cardiovascular drugs in post-mortem whole blood samples from forensic autopsy cases.
- Published
- 2007
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50. Headspace gas chromatographic determination of ethanol: the use of factorial design to study effects of blood storage and headspace conditions on ethanol stability and acetaldehyde formation in whole blood and plasma.
- Author
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Kristoffersen L, Stormyhr LE, and Smith-Kielland A
- Subjects
- Acetaldehyde chemistry, Central Nervous System Depressants chemistry, Erythrocytes, Ethanol chemistry, Flame Ionization, Forensic Medicine methods, Humans, Oxidation-Reduction, Temperature, Time Factors, Acetaldehyde blood, Central Nervous System Depressants blood, Ethanol blood, Specimen Handling methods
- Abstract
Our headspace gas chromatographic flame ionization detection (HS-GC-FID) method for ethanol determination showed slightly, but consistently, low ethanol concentrations in whole blood (blood) in proficiency testing programs (QC-samples). Ethanol and acetaldehyde were determined using HS-GC-FID with capillary columns, headspace equilibration temperature (HS-T degrees ) of 70 degrees C and 20 min equilibration time (HS-EqT). Full factorial designs were used to study the variables HS-T degrees (50 degrees -70 degrees C), HS-EqT (15-25 min), ethanol concentration (0.20-1.20 g/kg) and storage at room temperature (0-6 days) with three sample-sets; plasma, hemolyzed blood and non-hemolyzed blood. A decrease in the ethanol concentration in blood was seen as a nearly equivalent increase in the acetaldehyde concentration. This effect was not observed in plasma, indicating chemical oxidation of ethanol to acetaldehyde in the presence of red blood cells. The variables showed different magnitude of effects in hemolyzed and non-hemolyzed blood. A decrease in ethanol concentration was seen even after a few days of storage and also when changing the HS-T degrees from 50 to 70 degrees C. The formation of acetaldehyde was dependent on all the variables and combinations of these (interactions) and HS-T degrees was involved in all the significant interaction effects. Favorable instrumental conditions were found to be HS-T degrees of 50 degrees C and HS-EqT of 15-25 min. The ethanol concentrations obtained for the range 0.04-2.5 g/kg after analyzing authentic forensic blood samples with a HS-T degrees of 50 degrees C were statistically significantly higher than at 70 degrees C (+0.0154 g/kg, p < 0.0001, n = 180). In conclusion, chemical oxidation of ethanol to acetaldehyde in the presence of red blood cells has been shown to contribute to lowered ethanol concentrations in blood samples. Storage conditions before analysis and the headspace equilibration temperature during analysis were important for the determination of blood ethanol concentrations.
- Published
- 2006
- Full Text
- View/download PDF
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