bluuebunny/crossref_metadata_2025_split huggingface dataset:
External Quality Assessment in Clinical Chemistry: Review of the Situation in Croatia with Particular Reference to Equipment
Authors: Juretić Dubravka , Čepelak Ivana , Flegar-Meštrić Zlata 
Published: October 2004

Abstract
The effect of the use of new flame photometers (Ciba Corning 480, Chiron, Salzburg, Austria) and multichannel analyzers (BM Hitachi 904 or BM Hitachi 911, both Boehringer GmbH, Mannheim, Germany) on analytical quality was assessed in a number of medical biochemical laboratories (n=58) at health centers and general hospitals that provide primary health care services for the respective catchment areas.
The laboratories were supplied during 1996 and 1997 with new equipment, as part of the First Croatian Health Project, Primary Health Care Subproject, carried out by the Croatian Ministry of Health and Croatian Institute of Health Insurance.
We evaluated analytical performance of these laboratories for 19 analytes, according to the results reported in the Croatian External Quality Assessment Program for medical biochemical laboratories, performed four times per year.
Changes of percentages of particular methods used by the participating laboratories were observed for inorganic phosphate, total bilirubin, urea and creatinine. Such changes were even more pronounced for enzymes, where changes in the measurement procedure such as incubation temperature and buffers were observed in the methods used.
Evaluation of method performance revealed that after the introduction of new equipment interlaboratory variation decreased, so that an increasing proportion of laboratories included in the Project produced results within the target limits.
Point-of-Care Testing: the Views of the Working Group of the Dutch Association of Clinical Chemistry
Authors: Janssen Hans W. , Bookelman Hans , Dols Jan L. S. , Elion Gerritzen Wiveka E. , de Keyzer Ries H. 
Published: October 2004

Abstract
There is clearly a demand for near-patient laboratory testing. Modern technological developments support its implementation, but these are not the only preconditions that need to be satisfied in order to successfully introduce decentralized testing. In part 2 of this paper we give a definition of decentralized testing. Part 3 presents the advantages and disadvantages. This list is a summary taken from the suggested literature. Part 4 examines the formal position of the clinical chemist. Of major importance to the situation in the Netherlands are the Care Institutions Quality Act and the Individual Health Care Professions Act. Part 5 discusses professional standards. Part 6 outlines practical considerations which might support the implementation of decentralized testing. The clinical chemist should play an active role in drawing up a discussion paper for his own hospital.
Antioxidant Enzyme Activities and Total Nitrite/ Nitrate Levels in the Collar Model. Effect of Nicardipine
Authors: Sözmen Eser Yildirim , Kerry Zeliha , Uysal Fevziye , Yetik Günay , Yasa Mukadder , Üstünes Levent , Onat Taner 
Published: October 2004

AbstractThere is a large body of literature describing the causative role of oxidative stress mediated by increased levels of reactive oxygen species in the pathogenesis of cardiovascular disease such as atherosclerosis, hypertension, and restenosis after angioplasty. The positioning of a soft silicone collar around the rabbit carotid artery elicits intimal thickening. The findings from recent studies demonstrated that both intimal thickening and atherosclerosis lead to synthesis of inducible nitric oxide synthase, resulting in abundant amounts of nitric oxide. We investigated the effects of collaring and nicardipine treatment on the activities of antioxidant enzymes, superoxide dismutase and catalase, and total nitrite/nitrate levels, stable products of nitric oxide. Placing the collar increased the total nitrite/nitrate levels and decreased superoxide dismutase activity in collared arteries. Treatment with nicardipine (20 mg/kg/day, s.c.) prevented enhanced nitric oxide degradation without affecting superoxide dismutase and catalase activities. Our results suggest that enhanced nitric oxide production and superoxide anion are generated in response to the collaring, resulting in oxidative stress within the segment in this model.
Comparison of Procalcitonin, sCD14 and Interleukin-6 Values in Septic Patients
Authors: Herrmann Wolfgang , Ecker Daniel , Quast Sabine , Klieden Marion , Rose Stefan , Marzi Ingo 
Published: October 2004

Abstract
The aim of the study was to investigate whether procalcitonin, soluble CD14 and interleukin-6 show advantages in predicting the outcome and specificity for bacterial infection in patients with sepsis in comparison to common C-reactive protein measurement. Laboratory parameters were measured in plasma of patients during 14 days following the diagnosis of sepsis. Patients fulfilling the ACCP/SCCM criteria for sepsis were admitted to an intensive care unit (n=35). Procalcitonin was measured with an immunoluminometric assay, and soluble CD14 and interleukin-6 were analysed by ELISA. C-reactive protein was determined nephelometrically. Measurements were performed on days 0, 1, 2, 3, 4, 7 and 14. Separating the patients into survivors (n=22) and non-survivors (n=13), it was demonstrated that non-survivors mostly exhibited, after the day of admission, increasing procalcitonin concentrations which peaked around days three and four. In contrast, the procalcitonin concentrations of survivors fell continuously to the value of 2.1 ng/ml which was reported to be important for patients prognosis. The difference between procalcitonin median values of survivors (n=22) and non-survivors (n=13) attained the level of statistical significance on day 7 and on day 14 (p=0.05). When comparing the median values of C-reactive protein, soluble CD14 and interleukin-6 between survivors and non-survivors, no significant differences were detectable. In this study, plasma concentrations of soluble CD14 and interleukin-6 showed no predictive value for patients' outcome as compared with established laboratory parameters such as C-reactive protein or leukocyte count. Monitoring of procalcitonin seemed to detect severe episodes of sepsis and may improve the laboratory monitoring of septic patients.
Analytical Performance of the Fully Automated AxSYM(r) Estradiol Assay
Authors: Reinsberg Jochen , Jost Eberhard 
Published: October 2004

Abstract
The test performance of the fully automated AxSYM® Estradiol available on the immunoassay analyser Abbott AxSYM® was evaluated. Imprecision, sensitivity and linearity of dilution were examined. For assessment of accuracy, the assay results measured in 12 control pools and 9 patient samples were compared with the values obtained with isotope dilution—mass spectrometry (reference method). The correlation with the manual radioimmunoassay Estradiol MAIA® was evaluated using 140 serum samples with estradiol concentrations ranging from 0 to 10 nmol/l. Imprecision studies revealed for the AxSYM® Estradiol within-run coefficients of variation of 2.8–8.4% and day-to-day coefficients of variation of 3.4–9.5% (concentration range 0.3–2.8 nmol/l). The lower limit of quantification (lowest estradiol concentration with a day-to-day coefficient of variation <20%) was <0.11 nmol/l; the lower limit of detection was <0.05 nmol/l. The estradiol concentration recovered in patient samples after dilution did not differ by more than 10% from the expected values. The estradiol concentration measured with the AxSYM® Estradiol in 12 commercial control pools in some cases grossly deviated from the reference method values; however, for 9 individual patient samples the AxSYM results deviated by not more than 22% (−11%−+22%). There was a good overall correlation (coefficient of correlation = 0.989) between the results measured with the AxSYM® Estradiol and the Estradiol MAIA® in patient samples.
The AxSYM® Estradiol assay exhibits a good precision and a sufficient degree of sensitivity for measurement of estradiol in serum of menstruating women. Although the AxSYM results measured in the control pools, in some cases did not meet the target values, the good correlation with the Estradiol MAIA® indicates that the reliability of the AxSYM® Estradiol for clinical practice is comparable with well established radioimmunoassays. Thus, the AxSYM® Estradiol offers an alternative which is comparable with respect to clinical reliability but has great advantages in view of rapidity, flexibility and convenience of analysis.
Impacts of Laboratory Methodology on Medical Thinking in the 19th Century
Authors: Büttner Johannes 
Published: October 2004

Abstract
During the 19th century the first laboratories at hospitals and clinics in Central Europe were established. These ‘clinical laboratories’ were devoted to chemical analyses in practical medicine and clinical research. A characteristic feature of these laboratories was the use of measuring instruments, e.g. volumetric apparatus, polarimeters, spectroscopes, colorimeters, photometers. Using these techniques new phenomena were introduced into clinical medicine which could serve as signs in the diagnosis of diseases. Many of the new diagnostic signs were quantitative data as results of measurements. Their main advantage was the greater differentiation in the description of phenomena compared with the qualitative data used before. Another important characteristic of the new diagnostic signs was the discovery of causal relations to physiological and pathological processes in the organism. The physicians and chemists in the clinical laboratory were eager not only to collect empirical data but also to find causal relationships by research work similar to that carried out in physics and chemistry. Once causal chains were been identified more general relationships became clear. One example is the concept of metabolism which comprised a dynamic view on chemical processes in the body and the variation of "Stoff" (material) in time, including a quantitative input-output analysis of the body in health and disease. In the second half of the 19th century, scientifically based diagnostic signs began to replace the traditional symptoms and signs used since antiquity.
Near-Infrared Reflectance Spectroscopy for Noninvasive Monitoring of Metabolites
Authors: Heise H. Michael , Bittner Andreas , Marbach Ralf 
Published: October 2004

Abstract
An important class of substances in clinical chemistry are metabolites in body fluids, which are accessible by near-infrared spectroscopy without sample treatment using reagentless, fast and readily automated in vitro assays. Furthermore, noninvasive sensing systems are under development for the determination of blood glucose, especially for diabetic patients or for monitoring in intensive care and surgery. Near-infrared diffuse reflectance spectrometry of skin was employed allowing a certain tissue volume to be integrally probed. For calibration, the partial least-squares (PLS) algorithm was used either based on wide spectral intervals or using special spectral variable selection. Capillary blood glucose reference concentrations were obtained by finger pricking and an automated laboratory method (hexokinase/G6P-DH). Clear evidence is provided for the physical effect, as manifested by the spectral glucose absorptivities, underlying the individual single-person calibration models, which still require improvements in the methodology in the normo- and hypoglycemic concentration range. In extending the potential of noninvasive blood assays by infrared spectroscopy, a novel technique is presented for probing the intravascular fluid space by using fast spectral near-infrared measurements of skin tissue. The pulsatile blood spectrum can be derived from reflectance spectra of oral mucosa by Fourier analysis (near-infrared plethysmography). Future applications and prospects for noninvasive blood assays are discussed.
Evaluation of RNA Isolation Methods and Reference Genes for RT-PCR Analyses of Rare Target RNA
Authors: Mannhalter Christine , Koizar Daniela , Mitterbauer Gerlinde 
Published: October 2004

Abstract
Reverse transcription polymerase chain reaction (RTPCR) analysis is increasingly becoming part of the diagnostic and prognostic evaluation for hematologic and oncologic disorders. Currently, different RNA isolation methods are used in the diagnostic laboratories. No data are available on their suitability for sensitive detection of breakpoint cluster region-abelson (BCR-ABL) gene transcripts. We have extracted RNA from mononuclear cell (MNC) fractions and from lysed blood samples of 4 patients (1 with leukocytosis, 1 with chronic myelogeneous leukemia (CML) under interferon treatment, and 2 CML patients after bone marrow transplantation) with 3 RNA isolation reagents (TRIzol™, RNAzol™, FastTube™ reagent). RNA yield was slightly higher with RNAzol™ than with TRIzol™ as indicated by agarose gel electrophoresis and spectrophotometric measurement at 260 nm. The FastTube™ reagent was unsuitable for RNA isolation from MNC, and was not evaluated for lysed blood. Quantitative competitive RT-PCR amplification of the ABL gene showed comparable results for RNA isolated with RNAzol™ and TRIzol™. In RNA samples extracted from lysed whole blood, the presence of amplifiable RNA/cDNA was confirmed by amplification of 4 selected reference genes (porphobilinogen deaminase (PBGD), ABL, the gene spanning the BCR on chromosome 22 and retinoic acid receptor alpha (RARA)) in a multiplex PCR. High quality, DNA-free RNA was obtained with RNAzol™, and 1 BCR-ABL-positive (specific for translocation t [9; 22]) cell among 2×104 normal cells was successfully detectable by single step RT-PCR. In RNA isolated with TRIzol™, major contaminations with genomic DNA were observed which significantly impaired the interpretation of the results of RT-PCR analysis.
Interferon β1a Therapy Changes Lipoprotein Metabolism in Patients with Multiple Sclerosis
Authors: Sena Armando , Pedrosa Rui , Ferret-Sena Véronique , Almeida Rita , Andrade Maria Lurdes , Morais Maria Graça , Couderc Rémy 
Published: October 2004

Abstract
To assess whether interferon β1a (IFNβ1a) therapy affects plasma lipoprotein metabolism, twelve patients with relapsing-remitting multiple sclerosis (MS) were studied during a two-year follow-up period. High density lipoprotein (Hdl2) cholesterol and the Hdl2/Hdl3 ratio were increased at year 2 and lipoprotein (a) was transitorily increased at year 1, in comparison to baseline levels. Apolipoprotein A-I was lower and apolipoprotein E higher at year 1, only in a subgroup of patients who experienced relapses and/or progressed during therapy. These findings suggest that IFNβ1a treatment is associated with changes in the lipoprotein metabolism. Alterations in this metabolism could be related to the immunomodulatory actions of the drug and the disease activity in multiple sclerosis patients.
On-Line Analysis of Electrolytes in Extracorporeally Circulating Blood: Application of a Rat Model to Examine the Effect of a Single Pharma-cological Dose of Melatonin on Electrolyte Levels in Blood
Authors: Heidrich Jens P. , Niemeier Anja , Seyfarth Michael , Dibbelt Leif 
Published: October 2004

Abstract
An experimental model was developed to study the kinetics of electrolytes under different physiological and/or pathological conditions. The model was applied to investigate in vivothe effect of a pharmacological dose of melatonin on the concentrations of Ca2+, K+, Na+, and pH in the anticoagulated blood of anaesthetized male Wistar rats (250–350 g). After the application of 0.25 mg melatonin/kg body weight, injected intraperitoneally into each of 8 rats, the electrolytes were measured by a flow-through system with highly sensitive ion-selective electrodes. The results were compared to a control group (n=8) which was treated with diluent (saline). The electrolytes were monitored continuously via an extracorporeal circulation, on-going for at least 60 min. Melatonin induced a significant increase of blood Ca2+ (p<0.02) by an average of 9.9% after 60 min. However, total calcium concentration did not increase significantly. The extracorporeal circulation provoked an elevation of K+ by hemolysis. This K+ increase was slightly diminished by melatonin (p<0.06). No melatonin effects were seen on Na+, pH and magnesium in blood and plasma, respectively. Also, the urine concentrations of the electrolytes were not altered by melatonin. The mechanism by which melatonin influences the blood concentrations of ionized calcium and potassium is not yet understood.
Human Heart-Type Cytoplasmic Fatty Acid-Binding Protein (H-FABP) for the Diagnosis of Acute Myocardial Infarction. Clinical Evaluation of H-FABP in Comparison with Myoglobin and Creatine Kinase Isoenzyme MB
Authors: Okamoto Fumio , Sohmiya Koichi , Ohkaru Yasuhiko , Kawamura Keishiro , Asayama Kumiko , Kimura Hiroshi , Nishimura Shinzo , Ishii Hiroo , Sunahara Noriyuki , Tanaka Takao 
Published: October 2004

Abstract
Heart-type fatty acid-binding protein (H-FABP) is a low molecular weight cytoplasmic protein and present abundantly in the myocardium. When the myocardium is injured, as in the case of myocardial infarction, low molecular weight cytoplasmic proteins including H-FABP are released into the circulation and H-FABP is detectable in a blood sample. We have already developed a direct sandwich-ELISA for quantification of human H-FABP using two distinct types of monoclonal antibodies specific for human H-FABP. In this study we investigated the clinical validity of H-FABP as a biochemical diagnostic marker in the early phase of acute myocardial infarction (AMI). To evaluate the diagnostic usefulness of H-FABP in the early phase of AMI, blood samples were obtained from the following patients within 12 hours after the appearance of symptoms, and serum levels of H-FABP were compared with those of conventional diagnostic markers, such as myoglobin and creatine kinase isoenzyme MB (CK-MB). Blood samples were collected from patients with confirmed AMI (n=140), patients with chest pain who were afterwards not classified as AMI by normal CK-MB levels (non-AMI) (n=49) and normal healthy volunteers (n=75). The serum concentration of H-FABP was quantified with our direct sandwich-ELISA. The concentration of myoglobin mass was measured with a commercial RIA kit. The serum CK-MB activity was determined with an immuno-inhibition assay kit. The overall sensitivity of H-FA B P, within 12 hours after the appearance of symptoms, was 92.9%, while it was 88.6% with myoglobin and 18.6% with CK-MB. The overall specificity of H-FABP was 67.3%, while it was 57.1% with myoglobin and 98.0% with CK-MB. The diagnostic efficacy rates with these markers were 86.2% (H-FABP), 80.4% (myoglobin) and 39.2% (CK-MB), respectively. The diagnostic validity of H-FABP was further assessed by receiver operating characteristic (ROC) curve analysis. The area under the curve (AUC) of H-FABP was 0.921, which was significantly greater than with myoglobin (AUC: 0.843) and CK-MB (AUC: 0.654). These parameters, such as sensitivity, specificity, diagnostic efficacy and diagnostic accuracy, obtained for patients with chest pain within 3 hours and/or 6 hours after the onset of symptoms were almost the same as those for patients within 12 hours after symptoms. H-FABP is more sensitive than both myoglobin and CK-MB, more specific than myoglobin for detecting AMI within 12 hours after the onset of symptoms, and shows the highest values for both diagnostic efficacy and ROC curve analysis. Thus, H-FABP has great potential as an excellent biochemical cardiac marker for the diagnosis of AMI in the early phase.
Quality Control of Coated Antibodies:
New, Rapid Determination of Binding Affinity
Authors: Ricoux Rémy , Chazaud Bénédicte , Tresca Jean-Pierre , Pontet Michel 
Published: October 2004

Abstract
A procedure is described for the determination of the affinity constant between a fluid-phase biotinylated antigen and a solid-phase monoclonal antibody. This procedure allows evaluation of the efficiency of an antibody as a coated tool for an immunoassay. For this purpose, the biotinylation of the antigen and its further quantitative measurement by streptavidin-peroxidase led to a single reversible interaction, the binding affinity of which greatly determines the quality of the assay. The free and bound fractions of the biotinylated antigen were obtained in wells coated with a low level of immobilized antibodies. At the equilibrium state, the free antigen present in the supernatant of these wells was further transferred to high level antibody coated wells which captured all the free antigen molecules. These molecules were quantified using a standard curve established with known concentrations of biotinylated antigen, also incubated in wells coated with the high level of antibody.
Determination of Reticulocytes: Three Methods Compared
Authors: Siekmeier Rüdiger , Bierlich Alexa , Jaroß Werner 
Published: October 2004

Abstract
Determination of reticulocytes in peripheral blood is a valuable tool for getting information about erythropoiesis of an individual. For many years, reticulocyte numbers were quantified manually by means of a microscope after staining with supravital dyes. However, this method is tedious and shows low reproducibility. Therefore, several methods for the automated determination of reticulocytes have been established in laboratory routine within the last years. The aim of this study was to compare three of these automated methods for reticulocyte analysis. Reticulocytes were determined in 130 subsequent routine samples by means of an ABX Pentra 120 Retic haematological analyser, a Coulter EPICS XL MCL flow cytometer and a Coulter STKS haematology system, using the fluorescent dye thiazole orange or the supravital dye new methylene blue for reticulocyte staining, respectively. The reticulocyte concentrations were slightly lower for the Coulter STKS haematology system (mean ± SD 1.89 ± 1.32%) when compared with the Coulter EPICS XL MCL flow cytometer or the ABX Pentra 120 Retic haematological analyser (2.11 ± 1.25% and 2.12 ± 1.15%, respectively). The correlations between all methods were significant (rs ≥ 0.843, p < 0.001). Small intercepts were, however, observed in the correlation plots between the values obtained by means of the Coulter STKS haematology system and those obtained by the other two methods. Within-batch coefficients of variation were 6.0%, 6.9% and 7.8% for the ABX Pentra 120 Retic haematological analyser, the Coulter STKS haematology system and the Coulter EPICS XL MCL flow cytometer, respectively. The corresponding between-batch coefficient of variation values were 6.8%, 4.9% and 5.3% as well as 14.1%, 7.6% and 6.1% for the low, medium and high control levels determined by means of the ABX Pentra 120 Retic haematological analyser and the Coulter STKS haematology system, respectively. These data suggest that all three methods allow the efficient and reliable determination of reticulocyte counts under clinical routine conditions. However, although the obtained data are very similar, differences exist which should be taken into account for the normal values of the different methods.