Publications by authors named "Peter Astrup Christensen"

Article Synopsis
  • Head injuries are common in emergency departments and prompt diagnosis is essential for patient care and efficiency.
  • The study evaluates two faster blood collection tubes (RST and HIR) compared to standard tubes for measuring S100B, which helps assess head injury risks in patients.
  • Results indicate that the RST tube significantly reduces turnaround time with comparable accuracy, suggesting it could improve patient flow in the emergency setting.
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Introduction: P-Vitamin B12 is a commonly used biochemical test. Evaluation of test results and diagnosis of vitamin B12 deficiency are challenging, and the role of different biochemical methods remains unclear.

Methods: The aim of this study was to establish reference intervals for plasma vitamin B12 concentration using different immunoassays (method 1: Alinity, Abbott Laboratories; method 2: Cobas 6000, Roche Diagnostics; method 3: Atellica IM, Siemens Healthineers).

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Parathyroid hormone (PTH) is a routine biochemical analysis, and it varies whether a second- or third-generation assay is used. Information on the levels obtained with different assays and evidence to substantiate local assay-specific reference ranges are important to inform clinical practice. Prior to a shift from the second- to the third-generation PTH assay (Cobas 8000, Roche Diagnostics) in the Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark, a total of 59 EDTA-plasma samples were collected for method comparison (Passing-Bablok).

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Objective: Thyroid disease in women of reproductive age is mainly of autoimmune origin, and thyroid peroxidase antibodies (TPO-Ab) as well as thyroglobulin antibodies (Tg-Ab) are key markers. Adding to this, much focus in pregnancy is on euthyroid women who are thyroid antibody positive. Evidence to substantiate the cut-offs for the definition of thyroid autoantibody positivity in early pregnant women is warranted.

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Context: Thyrotropin (TSH) receptor antibodies (TRAb) are important when distinguishing between Graves' and gestational hyperthyroidism, but sparse evidence exists on the recommended cutoff during pregnancy.

Objective: This work aimed to establish a method- and pregnancy-specific cutoff for TRAb, to describe the frequency of TRAb positivity in early pregnancy, and to follow up the women in the years after pregnancy.

Methods: This cohort study used the North Denmark Region Pregnancy Cohort and Danish nationwide registers of women in the North Denmark Region who had a blood sample drawn in early pregnancy, 2011 to 2015, that was stored in a biobank for assessment of thyroid function and thyroid autoantibodies.

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The analytical stability of laboratory tests relies mostly on internal and external quality control procedures. Summarized patient data has in several studies been shown to be a good supplement for monitoring analytical stability. In our present investigation, we evaluate a datamining method for retrospective evaluation and assessment of analyte stability in whole blood.

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Objectives: Indirect data mining methods have been proposed for review of published reference intervals (RIs), but methods for identifying patients with a low likelihood of disease are needed. Many indirect methods extract test results on patients with a low frequency blood sampling history to identify putative healthy individuals. Although it is implied there has been no attempt to validate if patients with a low frequency blood sampling history are healthy and if test results from these patients are suitable for RI review.

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Around 1.5% of the total clinical biochemistry tests performed in laboratories are affected by preanalytical errors. Large, automated chemistry analysers prevent errors and interference by using control systems such as spectrophotometric measurements to evaluate serum indices, i.

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Intestinal infarction is the fast-evolving endpoint of impaired blood perfusion to an intestinal segment which may have fatal outcome. Early diagnosis and treatment within 6 h reduce mortality. Currently, d-lactate is a promising biomarker, however, not available in the acute clinical setting.

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Background: Severe hypertriglyceridemia (HTG) is a well-known risk factor for acute pancreatitis, but updated population-based estimates on incidence of HTG-associated pancreatitis are lacking.

Methods: We identified all individuals with severe HTG (triglyceride level >10 mmol/L [886 mg/dL]) in a population-based sample from 2008 to 2019 and linked these with Danish nationwide health-registers to identify patients with acute pancreatitis. Pancreatitis cases were subsequently confirmed by a detailed medical chart review.

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Context: Physiological alterations challenge the assessment of maternal thyroid function in pregnancy. It remains uncertain how the reference ranges vary by week of pregnancy, and how the classification of disease varies by analytical method and type of thyroid function test.

Design: Serum samples from Danish pregnant women (n = 6282) were used for the measurement of thyrotropin (TSH), total and free thyroxine (T4), total and free 3,5,3'-triiodothyronine (T3), and T-uptake using "Method A" (Cobas 8000, Roche Diagnostics).

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Background: Physiological changes in maternal thyroid function during pregnancy necessitate the use of pregnancy-specific reference ranges. Dynamic changes in thyrotropin (TSH) within the first trimester of pregnancy have been reported, but more evidence is needed to substantiate the findings. The objective of this study was to estimate pregnancy week-specific reference ranges for maternal TSH and free thyroxine (fT4) in early pregnancy.

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Background: Definition and elimination of outliers is a key element for medical laboratories establishing or verifying reference intervals (RIs). Especially as inclusion of just a few outlying observations may seriously affect the determination of the reference limits. Many methods have been developed for definition of outliers.

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Background: Transference of reference intervals (RIs) from multicentre studies are often verified by use of a small number of samples from reference individuals or by the use of one serum sample (Serum X for NORIP RI). Despite recommended and appropriate methods, both have inconveniencies and drawbacks. Several attempts have been made to develop an indirect method, which uses historical data from the laboratory.

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Correct reference intervals are an important part of test results. As establishing own reference intervals is a very expensive task, the NORIP reference intervals are often transferred for use in Nordic laboratories. The NORIP reference interval on P-Albumin was here compared to current results for laboratories using the bromocresol purple (BCP) method for P-Albumin.

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Objectives: Macrophages are important cells in immunity and the main producers of pro-inflammatory cytokines. The main objective was to evaluate if specific delivery of glucocorticoid to the macrophage receptor CD163 is superior to systemic glucocorticoid therapy in dampening the cytokine response to lipopolysaccharide infusion in pigs.

Design: Two randomized, placebo-controlled trials.

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Antibodies capable of recognizing key molecular targets isolated e.g. by phage display technology have been used in the pursuit of new and improved therapies for prevalent human diseases.

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The 29-residue peptide hormone glucagon has been used as a model system for the study of amyloid-like fibrils. Atomic force microscopy (AFM) studies have detected putative oligomeric species during this lag phase, but this has not been confirmed by any spectroscopic technique. Here we use an attached pyrene group to detect association (excimer formation) between individual glucagon molecules.

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The Thomsen-Friedenreich disaccharide (TF) is a promising target antigen for tumor immunotherapy, since it is almost exclusively expressed in carcinoma tissues. The TF-specific antibodies generated so far are IgMs of mouse origin with limited therapeutic potential. Phage-displayed scFv repertoires are an established source for recombinant antibodies; however, we were unable to identify scFvs binding to TF when applying libraries in the standard monovalent display format of phagemid systems.

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Producing monoclonal antibodies includes their efficient and simple purification. Growing hybridoma cells in media containing Prolifix, an alternative plant-based substitute for serum, provides supernatants containing large amounts of antibodies and defined low molecular weight additives. Antibodies can easily be separated from these compounds by fast ultrafiltration.

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Functional expressions of proteins often depend on the presence of host specific factors. Frequently recombinant expression strategies of proteins in foreign hosts, such as bacteria, have been associated with poor yields or significant loss of functionality. Improvements in the performance of heterologous expression systems will benefit present-day quests in structural and functional genomics where high amounts of active protein are required.

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Antiidiotypic antibodies (Ab2) are needed as tools for a better understanding of molecular mimicry and the immunological network, and for many potential applications in the biomedical and pharmaceutical field. Antiidiotypic antibodies mimicking carbohydrate or conformational epitopes (Ab2beta) are of considerable interest as surrogate immunogens for cancer vaccination. However, it has so far been difficult and tedious to produce Ab2s to a given antigen.

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