Clinical Chemistry and Laboratory Medicine (CCLM)

Published by De Gruyter

Volume 37 Issue 8

Issue of Clinical Chemistry and Laboratory Medicine (CCLM)

Contents
Journal Overview

June 1, 2005

Oxidized Low Density Lipoprotein: Atherogenic and Proinflammatory Characteristics during Macrophage Foam Cell Formation. An Inhibitory Role for Nutritional Antioxidants and Serum Paraoxonase

Marielle Kaplan, Michael Aviram

Page range: 777-787

Abstract

Oxidative stress and inflammatory processes are of major importance in atherogenesis because they stimulate oxidized LDL (Ox-LDL)-induced macrophage cholesterol accumulation and foam cell formation, the hallmark of early atherosclerosis. Under oxidative stress, both blood monocytes and plasma lipoproteins invade the arterial wall, where they are exposed to atherogenic modifications. Oxidative stress stimulates endothelial secretion of monocyte chemoattractant protein 1 (MCP-1) and of macrophage colony stimulating factor (M-CSF), leading to monocyte adhesion and differentiation, respectively. LDL binds to extracellular matrix (ECM secreted by endothelial cells, smooth muscle cells and macrophages) proteoglycans, in a process that contributes to the enhanced susceptibility of the lipoprotein to oxidation by arterial wall macrophages. ECM-retained Ox-LDL is taken up by activated macrophages via their scavenger receptors. This leads to cellular cholesterol accumulation and enhanced atherogenesis. Protection of LDL against oxidation by antioxidants that can act directly on the LDL, or indirectly on the cellular oxidative machinery, or conversion of Ox-LDL to a non-atherogenic particle by HDL-associated paraoxonase (PON-1), can contribute to attenuation of atherosclerosis.

June 1, 2005

Molecular Aspects and Natural Source of Procalcitonin

Stefan Russwurm, Matthias Wiederhold, Mathias Oberhoffer, Ilmars Stonans, Peter F. Zipfel, Konrad Reinhart

Page range: 789-797

Abstract

The search for sensitive and specific markers of systemic infection has shown that procalcitonin levels are increased in sepsis, and, consequently, this plasma protein has come into the focus of clinical research. Human procalcitonin is encoded by the Calc-I gene, which gives rise to two alternatively spliced transcripts. Despite systemic investigation of the Calc-I gene and mechanisms of the tissue-specific regulation and alternative splicing, little is known about the biology of procalcitonin and the cells which express this protein during inflammation. Here we focus on the molecular and biochemical properties of the molecule and summarize the known biological functions of procalcitonin. We report on the structure of the Calc-I gene, the amino acid conservation of procalcitonin in different species, and the consensus sequences of the protein with regard to sites relevant for posttranslational modification, spatial distribution, and homologies to other cytokines. We discuss aspects of intracellular location of procalcitonin and demonstrate that it has the characteristics of a secreted protein.

June 1, 2005

Urinary Porphyrin Excretion in Hepatitis C Infection

Michael Vogeser, Karl Jacob, Reinhart Zachoval

Page range: 799-804

Abstract

A high prevalence of hepatitis C virus infection in porphyria cutanea tarda in some populations suggests a close link between viral hepatitis and alteration of porphyrin metabolism. Moreover, there is evidence of a role of porphyrinopathies in hepatocarcinogenesis. The aim of our study was to obtain data on the prevalence and patterns of heme metabolism alterations in patients with chronic hepatitis C virus infection. Urinary porphyrin excretion was prospectively studied in 100 consecutive outpatients with chronic hepatitis C infection without signs of photosensitivity, using an ion-pair high-performance liquid chromatography method. Increased total porphyrin excretion was found in 41 patients, with predominant excretion of coproporphyrins (whole study group: mean 146 μg/g creatinine, interquartile range 76–186; normal < 150), in 10 patients excretion exceeded 300 μg/g creatinine. In the majority of all patients studied (75/100) an increased ratio of the relatively hydrophobic coproporphyrin isomer I to isomer III was found. In just one case, urinary porphyrin pattern characteristic for chronic hepatic porphyria was present (uroporphyrin > coproporphyrin, heptacarboxyporphyrin III increased) but the total porphyrin excretion was only slightly elevated in this case. In the whole group, total urinary porphyrin excretion correlated well with serum bilirubin and was inversely correlated with albumin and thrombin time. In conclusion, secondary coproporphyrinuria occurs frequently in heptatitis C infection, whereas in Germany, preclinical porphyria cutanea tarda seems to be rare in these patients.

June 1, 2005

Quantification of Low Abundance Natriuretic Peptide Receptor mRNA in Rat Tissues

Klaus Höhnel, Rainer Dietz, Roland Willenbrock

Page range: 805-812

Abstract

Natriuretic peptides are important regulators of vascular resistance and volume and electrolyte homeostasis. The quantification of natriuretic peptide receptor (NPR) mRNA is important for the understanding of the regulation of this humoral system, but is difficult due to low expression of the NPR mRNA. We report here on the evaluation of a polymerase chain reaction (PCR)-aided transcript titration assay for quantification of all three NPR subtypes (NPR-A, NPR-B, and NPR-C) mRNA. A multispecific internal standard RNA with parts of NPRA, NPR-B, NPR-C and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) nucleotide sequences was constructed and reverse transcription of standard and sample RNA (400 ng) was performed in parallel for all three NPRs and GAPDH. The specific PCR yielded differently sized products, which were quantified by high performance liquid chromatography (HPLC). The determination of specific mRNA concentrations was not influenced by cDNA input and did not depend on the PCR cycle number. Linearity between sample RNA input and mRNA concentration was demonstrated. Application of the evaluated method showed that the NPR-A mRNA expression was the most abundant of the three natriuretic peptide receptor mRNAs in rat lungs, glomeruli and left ventricles, followed by the NPR-C mRNA and the NPR-B mRNA expression. Thus, the described method allows the reliable quantification of the specific mRNA expression of all three NPRs with small amounts of RNA. The presented method might foster future research on the regulation of this humoral system in cardiovascular and kidney diseases.

June 1, 2005

Rat Tissue Collagen Modified by Advanced Glycation: Correlation with Duration of Diabetes and Glycemic Control

Zdenka Turk, Irena Mišur, Nikša Turk, Bojan Benko

Page range: 813-820

Abstract

Collagenous proteins are especially prone to nonenzymatic glycation, because they contain several dibasic amino acid residues with free amino groups, have a very slow turnover rate, and are exposed to ambient levels of glucose. The aim of this study was to determine the time-dependent course of advanced glycation process in diabetic rats in relation to glycemic control and duration of diabetes, compared to age-matched controls. Immunochemical assay with antibodies to advanced glycation end products (AGE) was first developed to qualitatively detect and quantify the AGE formed in rat tendon and aortic collagen. Individual collagen samples were extracted by extensive pepsin and collagenase digestion. The amount of AGE was measured by competitive ELISA and results were expressed as AGE U/mg collagen. Diabetic rats showed a significant increase in AGE content in aortic collagen at 20 weeks (n=6, 206.6 ± 16.7 U/mg collagen) compared with that measured at 4 and 12 weeks (n=6, 110 ± 12.8 U/mg collagen, and n=13, 184.9 ± 12.3 U/mg collagen at 4 and 12 weeks, respectively; p < 0.001 between 20 weeks and 4 weeks; p < 0.01 between 20 weeks and 12 weeks). The amount of AGE in tendon collagen of diabetic rats increased from 1.9 ± 0.38 U/mg at 4 weeks to 11.2 ± 6.1 U/mg collagen at 20 weeks, p < 0.001. Considerable disparity was observed in the intensity of glycation between aortic and tendon collagen. AGE-content per mg of aortic collagen was several-fold to that found in tendon collagen (p < 0.001). To investigate the effect of glycemic control on the advanced glycation process, total aortic AGE-collagen content was compared between untreated diabetic rats (D; n=13, 184.9 ± 12.3 U/mg) and diabetic rats treated for 12 weeks with insulin (DI; n=6, 133.9 ± 10.7 U/mg), or phlorizin (DP; n=6, 132.4 ± 8.9 U/mg), or by a combination of insulin/phlorizin (DIP; n=6, 124.3 ± 6.5 U/mg). In spite of therapy used, all groups of diabetic animals had a significantly higher aortic AGE-collagen content than those in the nondiabetic control group (C: n=8, 104.6 ± 14.9 U/mg) of the same age (D, DI, DP, DIP vs. C, p < 0.001). Comparison between the mean levels of glycated hemoglobin (D: 5.62 ± 0.38 % vs. C: 1.7 ± 0.05 %) and mean AGE levels in the studied group of animals yielded a very good exponential correlation (r = 0.89, p < 0.001). Glycation-derived late-stage collagen modification was detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and by immunoblotting confirmed to contain (an) AGE-structure(s). Our study provides strong immunochemical evidence of AGE formation in vivo during hyperglycemia, and of their temporal association with structural alterations of extracellular matrix proteins. The advanced glycation process is retarded and reduced in intensity, but not completely abolished, by glycemia regulation with, or independently of, insulin.

June 1, 2005

Reference Values for a Homogeneous Ferritin Assay and Traceability to the 3rd International Recombinant Standard for Ferritin (NIBSC Code 94/572)

Johannes Lotz, Gerd Hafner, Winfried Prellwitz

Page range: 821-825

Abstract

Reference values for two ferritin assays (Tina-quant ® a Ferritin, Enzymun ® , both Roche Diagnostics, Mannheim, Germany) were established (136 males and 139 females). To rule out inflammation as well as iron deficiency in the reference population, subjects with the C-reactive protein concentration < 5 mg/l, and zinc protoporphyrin < 40 µmol/mol heme and the soluble transferrin receptor < 3 mg/l were selected. Taking into account latent iron deficiency as well as hereditary hemochromatosis the 5–95 percentile range was as follows: male, 27–365 μg/l; female, 13–148 μg/l for Tina-quant ® a and 12–151 μg/l for Enzymun ® . The Tinaquant ® a Ferritin assay showed a very good correlation (r≧0.990) to Enzymun ® ferritin, Ferritin Abbott ® (Abbott Diagnostics, Delkenheim, Germany), N Latex Ferritin ® (Dade Behring, Marburg, Germany) and the Ferritin Chiron ® (Chiron Diagnostics, Fernwald, Germany). However, the slopes of the standard principal component method analysis were calculated to be between 1.03 (Enzymun ® ) and 1.41 (N Latex Ferritin ® ). For four assays the median recovery of the 3rd International Recombinant Ferritin Standard (NIBSC 94/572) measured by serial dilution was 89–109 %. The N Latex Ferritin ® assay recovered half of the target values. Because of the good correlation with other assays, a matrix effect is likely. The question arises whether the manufacturers' agreement on the recombinant

June 1, 2005

Iron Saturation of Ferritin in the Course of Phlebotomy Treatment in Patients with Haemochromatosis

Joop ten Kate, Kirstin Marell, Reint Huizinga, Herman Kreeftenberg, Cees van Deursen

Page range: 827-830

Abstract

This paper describes the iron saturation of ferritin haemochromatosis patients during phlebotomy therapy. The iron saturation of ferritin does not change during therapy and cannot be used as a parameter follow therapy. Furthermore, the iron saturation seems to be a constant characteristic of a given person. It does not vary with the body iron stores in patients with haemochromatosis.

June 1, 2005

Neural Networks for the Biochemical Prediction of Bone Mass Loss

Josep M. Queraltó, Josep Torres, Misericordia Guinot

Page range: 831-838

Abstract

Neural networks are specialized artificial intelligence techniques that have shown high efficiency in dealing with complex problems. Paradigms such as backpropagation have been successfully applied in a number of biomedical applications, but not in attempts to identify women at risk of postmenopausal osteoporotic complications. In this paper, several neural networks were trained using different combinations of biochemical variables as inputs. Bone densitometric measurements in Ward's triangle and in the spinal column were used as separate classification criteria (outputs) between slow and fast bone mass losers. The most parsimonious model with the best performance included plasma concentrations of estrone, estradiol, osteocalcin, parathyrin and urine concentrations of calcium and hydroxyproline (expressed as ratio to creatinine excretion) as input neurons; ten neurons in a single hidden layer; and one neuron in the output layer. Diagnostic efficiency was 76 % in Ward's triangle and 74 % in the spinal column; sensitivity was 70 and 81 %, and specificity was 77 and 65 %, respectively. Linear discriminant analysis showed a diagnostic efficiency of 66 % in Ward's triangle and 64 % in the spinal column, sensitivity was 55 and 86 %, and specificity was 75 and 13 %, respectively. We conclude that performance of the stepwise discriminant analysis was not superior to the neural networks.

June 1, 2005

Serum Dipeptidyl Peptidase IV Activity Correlates with the T-Cell CD26 Antigen

Serenay Elgün, Aytaç Keskinege, Hamdi Akan, Levent Karaca

Page range: 839-840

June 1, 2005

The Baltic Atherosclerosis Journal

Margus Viigimaa

Page range: 841-841

July 27, 2005

Concise Biochemistry, by Anatol Bezkorovainy and Max E. Rafelson Jr.

Wieslaw Makarewicz

Page range: 843-843

July 27, 2005

Cytokines in Severe Sepsis and Septic Shock, by H. Redl and G. Schlag

Andreas Meier-Hellmann

Page range: 844-844

About this journal

Objective
Clinical Chemistry and Laboratory Medicine (CCLM) publishes articles on novel teaching and training methods applicable to laboratory medicine. It is focused on basic and applied research and cutting-edge clinical laboratory medicine. CCLM is one of the leading journals in the field, with an impact factor over 8. All contributions submitted for publication in CCLM are single-blind peer reviewed by at least two experts in the field. CCLM is led by a multi-institutional editorial board. It is issued monthly, both in print and electronically. Letters to the Editor and Congress Abstracts are published online only.

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Topics

clinical biochemistry
clinical genomics and molecular biology
clinical haematology and coagulation
clinical immunology and autoimmunity
clinical microbiology
drug monitoring and analysis
evaluation of diagnostic biomarkers
disease-oriented topics (cardiovascular disease, cancer diagnostics, diabetes)
new reagents, instrumentation and technologies
new methodologies
reference materials and methods
reference values and decision limits
quality and safety in laboratory medicine
translational laboratory medicine
clinical metrology

Article formats
Research Articles, Reviews, Mini Reviews and Opinion Papers on all aspects of clinical chemistry and laboratory medicine, Guidelines and Recommendations, Point/Counterpoint Articles, Letters to the Editor, Editorials

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