| 1. |
- Kolsrud, Oscar, et al.
(författare)
-
Measured and not estimated glomerular filtration rate should be used to assess renal function in heart transplant recipients.
- 2016
-
Ingår i: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. - : Oxford University Press (OUP). - 1460-2385. ; 31:7, s. 1182-9
-
Tidskriftsartikel (refereegranskat)abstract
- In organ transplanted patients, impaired renal function is of major prognostic importance and influences therapeutic decisions. Therefore, monitoring of renal function with glomerular filtration rate (GFR) is of importance, both before and after heart transplantation (HTx). The GFR can be measured directly (mGFR) or estimated (eGFR) with equations based on circulating creatinine or cystatin C levels. However, these equations have not been thoroughly validated in the HTx population.
|
|
| 2. |
- Muslimovic, Aida, et al.
(författare)
-
The Liver and Kidneys mediate clearance of cardiac troponin in the rat
- 2020
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- Cardiac-specific troponins (cTn), troponin T (cTnT) and troponin I (cTnI) are diagnostic biomarkers when myocardial infarction is suspected. Despite its clinical importance it is still not known how cTn is cleared once it is released from damaged cardiac cells. The aim of this study was to examine the clearance of cTn in the rat. A cTn preparation from pig heart was labeled with fluorescent dye or fluorine 18 (18 F). The accumulation of the fluorescence signal using organ extracts, or the 18 F signal using positron emission tomography (PET) was examined after a tail vein injection. The endocytosis of fluorescently labeled cTn was studied using a mouse hepatoma cell line. Close to 99% of the cTnT and cTnI measured with clinical immunoassays were cleared from the circulation two hours after a tail vein injection. The fluorescence signal from the fluorescently labeled cTn preparation and the radioactivity from the 18F-labeled cTn preparation mainly accumulated in the liver and kidneys. The fluorescently labeled cTn preparation was efficiently endocytosed by mouse hepatoma cells. In conclusion, we find that the liver and the kidneys are responsible for the clearance of cTn from plasma in the rat.
|
|
| 3. |
- Ognissanti, Damiano, et al.
(författare)
-
Cardiac troponin T concentrations and patient-specific risk of myocardial infarction using the novel PALfx parameter
- 2019
-
Ingår i: Clinical Biochemistry. - : Elsevier BV. - 1873-2933 .- 0009-9120. ; 66, s. 21-28
-
Tidskriftsartikel (refereegranskat)abstract
- Myocardial infarction (MI) is more likely if the heart damage biomarker cardiac troponin T (cTnT) is elevated in a blood sample from a patient with chest pain. There is no conventional method to estimate the risk of MI at a specific cTnT concentration. The purpose of this study was to evaluate the performance of a novel method that converts cTnT concentrations to patient-specific risks of MI. Methods: Admission cTnT measurements in 15,425 ED patients from three hospitals with a primary complaint of chest pain, with or without a clinical diagnosis of MI, were Box-Cox-transformed to normality density functions to calculate the percentage with MI among patients with a given cTnT concentration, the parametric predictive value among lookalikes (PALfx). The ability of the PALfx to generate stable risk estimates of MI was examined by bootstrapping and expressed as the coefficient of variation (CV). Results: Four age and sex-specific subgroups above or below 60 years of age with distinct cTnT distributions were identified among patients without MI. The cTnT distributions across subgroups with MI were similar, allowing us to use all admissions with MI to calculate the PALfx in the four subgroups. For instance, at a baseline cTnT concentration of 7 ng/L, a female patient < 60 years would have a 0.5% risk of MI whereas a male patient > 60 years would have a 1.9% risk of MI. To assess the stability of the PALfx method we bootstrapped smaller and smaller subsets of the 15,422 ED visits. We found that 1950 patients without MI and 50 patients with MI were sufficient to limit the variation of the PALfx with a CV of 0.8–5.4%, close to the CV using the entire dataset. The MI risk estimates were similar when data from the three hospitals were used separately to derive the PALfx equations. Conclusions: The PALfx can be used to estimate the risk of MI at patient-specific cTnT concentrations with acceptable margins of error. The patient-specific risk of disease using the PALfx could complement decision limits.
|
|
| 4. |
- Singh, Vandana, 1985, et al.
(författare)
-
Quantification of single-strand DNA lesions caused by the topoisomerase II poison etoposide using single DNA molecule imaging
- 2022
-
Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 594, s. 57-62
-
Tidskriftsartikel (refereegranskat)abstract
- DNA-damaging agents, such as radiation and chemotherapy, are common in cancer treatment, but the dosing has proven to be challenging, leading to severe side effects in some patients. Hence, to be able to personalize DNA-damaging chemotherapy, it is important to develop fast and reliable methods to measure the resulting DNA damage in patient cells. Here, we demonstrate how single DNA molecule imaging using fluorescence microscopy can quantify DNA-damage caused by the topoisomerase II (TopoII) poison etoposide. The assay uses an enzyme cocktail consisting of base excision repair (BER) enzymes to repair the DNA damage caused by etoposide and label the sites using a DNA polymerase and fluorescently labeled nucleotides. Using this DNA-damage detection assay we find a large variation in etoposide induced DNA-damage after in vitro treatment of blood cells from healthy individuals. We furthermore used the TopoII inhibitor ICRF-193 to show that the etoposide-induced damage in DNA was TopoII dependent. We discuss how our results support a potential future use of the assay for personalized dosing of chemotherapy.
|
|
| 5. |
- von Otter, Malin, 1978, et al.
(författare)
-
Nrf2-encoding NFE2L2 haplotypes influence disease progression but not risk in Alzheimer's disease and age-related cataract
- 2010
-
Ingår i: Mechanisms of Ageing and Development. - : Elsevier BV. - 0047-6374 .- 1872-6216. ; 131:2, s. 105-110
-
Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) and age-related cataract, disorders characterized by protein aggregation causing late-onset disease, both involve oxidative stress. We hypothesize that common variants of NFE2L2 and KEAP1, the genes encoding the main regulators of the Nrf2 system, an important defence system against oxidative stress, may influence risk of AD and/or age-related cataract. This case-control study combines an AD material (725 cases and 845 controls), and a cataract material (489 cases and 182 controls). Genetic variation in NFE2L2 and KEAP1 was tagged by eight and three tag single nucleotide polymorphisms (SNPs), respectively. Single SNPs and haplotypes were analyzed for associations with disease risk, age parameters, MMSE and AD cerebrospinal fluid biomarkers. NFE2L2 and KEAP1 were not associated with risk of AD or cataract. However, one haplotype allele of NFE2L2 was associated with 2 years earlier age at AD onset (pc 0.013) and 4 years earlier age at surgery for posterior subcapsular cataract (p(c) = 0.019). Another haplotype of NFE2L2 was associated with 4 years later age at surgery for cortical cataract (p(c) = 0.009). Our findings do not support NFE2L2 or KEAP1 as susceptibility genes for AD or cataract. However, common variants of the NFE2L2 gene may affect disease progression, potentially altering clinically recognized disease onset. (C) 2010 Elsevier Ireland Ltd. All rights reserved.
|
|
| 6. |
|
|
| 7. |
- Hammarsten, Ola, et al.
(författare)
-
Evaluation of a Sensitive Copeptin Assay for Clinical Measurement
- 2012
-
Ingår i: The Open Clinical Chemistry Journal. - : Bentham Science Publishers Ltd.. - 2588-7785 .- 1874-2416. ; 5:1, s. 21-26
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract: Background: Copeptin, a marker of vasopressin production, has been introduced for earlier diagnosis of acute myocardial infarction and other clinical emergencies. We evaluated the analytical performance of a new generation copeptin assay in an inter-laboratory trial. Methods: Precision, linearity range, carry-over contamination, the limit of blank and an inter-laboratory comparison trial for the copeptin US KRYPTOR assay were performed on the B·R·A·H·M·S KRYPTOR compact PLUS. Results: The intra-assay imprecision (CVs) was 12.6–2.2% and total imprecision over five days was 12.3-4.3% between 3.1 and 18.2 pmol/L. The assay had excellent linearity between 7-222 pmol/L. The limit of blank was 2.5 pmol/L and the limit of detection was 3.2 pmol/L, but was dependent on the analyte-free material used. No significant difference between sample type, such as serum or different types of plasma or reagent lots, was noted. The copeptin results remained unchanged upon five repeated freeze-thaw cycles. A set of patient samples with a mean copeptin concentration of 2.1-61 pmol/L run at two separate sites showed close correlation (r2=0.99, slope=1.01, intercept=0.35), indicating comparable results across laboratories. Conclusion: The new ultrasensitive copeptin KRYPTOR assay shows excellent inter-lab precision, opening up the possibility for international guidelines to exclude acute myocardial infarction.
|
|
| 8. |
- Muslimovic, Aida, et al.
(författare)
-
Calibrators for Clinical Measurements of Phosphorylated H2AX in Patient Cells by Flow Cytometry
- 2012
-
Ingår i: The Open Clinical Chemistry Journal. - : Bentham Science Publishers Ltd.. - 2588-7785 .- 1874-2416. ; 5:1, s. 33-39
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract: Agents that induce DNA double-strand breaks (DSBs), such as ionizing radiation, are frequently used in cancer therapy. H2AX is rapidly phosphorylated in response to DSBs and serves as a way to measure the extent of DSBs induced in patient cells. We have previously reported a flow cytometry-based method for measuring H2AX phosphorylation in pa-tient cells undergoing radiotherapy. To be able to implement measurement of H2AX phosphorylation in clinical practice, we have characterized calibrators for the flow cytometry analysis based on phosphopeptide-coated beads and fixed cells. The calibrator beads and fixed cells lost less than 11% of the signal after storage for 40 days under optimal conditions and were able to correct for day-to-day variation in method performance.
|
|
| 9. |
- Oleröd, Göran, et al.
(författare)
-
The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status.
- 2017
-
Ingår i: Endocrine connections. - 2049-3614. ; 6:2, s. 111-120
-
Tidskriftsartikel (refereegranskat)abstract
- Serum 25-hydroxy vitamin D [25(OH)D] varies greatly with season at northern latitudes. The purpose of this study was to determine if the seasonal variations in serum total 25(OH)D are followed by a concomitant variation in free 25(OH)D or if the variation is damped by alterations in the binding capacity of DBP.Serum was collected from 540 healthy blood donors (60% men; mean age 41 ± 13 years) during 12 months and analyzed for total 25(OH)D, directly measured free 25(OH)D, vitamin D-binding protein (DBP) and albumin. Calculated free 25(OH)D was estimated.The UV-B radiation during the sampling month was positively correlated with the serum levels of total 25(OH)D (r = 0.355,P < 0.001), directly measured free (r = 0.336,P < 0.001) and calculated free 25(OH)D (r = 0.275,P < 0.001), but not with DBP and albumin. The percentage of free 25(OH)D was higher during the winter months than that during the summer months (0.020 ± 0.005% vs 0.019 ± 0.004%;P = 0.007) and higher in participants with a serum 25(OH)D below 25 nmol/L than that in participants with a serum 25(OH)D above 75 nmol/L (0.031 ± 0.007% vs 0.017 ± 0.003%;P < 0.001). iPTH was correlated with directly measured free 25(OH)D (r = -0.226;P < 0.001), but only weakly with calculated free 25(OH)D (r = -0.095;P = 0.027).Directly measured free serum 25(OH)D was highly correlated with total serum 25(OH)D and followed the same seasonal variation, whereas the serum concentrations of DBP and albumin were stable. The fluctuation in free 25(OH)D was only marginally damped with an increase in the percentage of free 25(OH)D during the winter months and in participants with vitamin D deficiency.
|
|
| 10. |
- Hammarsten, Ola, et al.
(författare)
-
Antibody-mediated interferences affecting cardiac troponin assays: recommendations from the IFCC Committee on Clinical Applications of Cardiac Biomarkers
- 2023
-
Ingår i: CLINICAL CHEMISTRY AND LABORATORY MEDICINE. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 61:8
-
Tidskriftsartikel (refereegranskat)abstract
- The International Federation of Clinical Chemistry Committee on Clinical Applications of Cardiac Biomarkers (IFCC C-CB) provides educational documents to facilitate the interpretation and use of cardiac biomarkers in clinical laboratories and practice. Our aim is to improve the understanding of certain key analytical and clinical aspects of cardiac biomarkers and how these may interplay. Measurements of cardiac troponin (cTn) have a prominent place in the clinical work-up of patients with suspected acute coronary syndrome. It is therefore important that clinical laboratories know how to recognize and assess analytical issues. Two emerging analytical issues resulting in falsely high cTn concentrations, often several fold higher than the upper reference limit (URL), are antibody-mediated assay interference due to long-lived cTn-antibody complexes, called macrotroponin, and crosslinking antibodies that are frequently referred to as heterophilic antibodies. We provide an overview of antibody-mediated cTn assay interference and provide recommendations on how to confirm the interference and interpret the results.
|
|
