bluuebunny/crossref_metadata_2025_split huggingface dataset:
The discordance rate, a new concept for combining diagnostic decisions with analytical performance characteristics. 2. Defining analytical goals applied to the diagnosis of type 2 diabetes by blood glucose concentrations
Authors: Haeckel Rainer , Wosniok Werner 
Published: August 2004

AbstractA novel statistical approach has recently been described to estimate diagnostic “errors” in method comparison studies. This procedure requires a population-based probability, pThe new concept was then applied in a reverse mode by determining the analytical variability of glucose concentrations for a fixed discordance rate diagnosing type 2 diabetes. If a combined discordance rate (sum of positive and negative discordances) of 5% is allowed, a maximal imprecision of 3.7% can be tolerated in the absence of bias. In the presence of a 3.0% bias, the allowable imprecision must be reduced to 2.8%. The relationship between bias and imprecision followed a complex function and not a simple linear model. These allowable limits were achieved with venous plasma in the fasting state.The allowable analytical specifications were slightly more stringent with capillary blood. After a 2 h glucose challenge, higher error rates could be tolerated, indicating that post-load glucose concentrations have a higher diagnostic efficiency than fasting levels. The new concept has the advantage that it is derived from patient's samples in relation to diagnostic requirements.
Effects of some pre-analytical conditions on the measurement of homocysteine and cysteine in plasma
Authors: Zighetti Maddalena L. , Chantarangkul Veena , Lombardi Rossana , Lecchi Anna , Cattaneo Marco 
Published: August 2004

AbstractThe association of hyperhomocysteinemia and hypercysteinemia with the risk of arterial and venous thrombosis is well documented. While it is known that standardized pre-analytical conditions are necessary for reliable measurement of plasma total homocysteine, the effects of pre-analytical conditions on cysteine measurement are less well known. The aim of this study was to evaluate the effects of pre-analytical conditions on the measurement of homocysteine and cysteine. We observed that the concentration of total homocysteine in plasma increased significantly with time (38% after 6 h), whereas total cysteine decreased (5% after 2h) when blood anticoagulated with ethylenediaminetetraacetic tripotassium salt was kept at room temperature. These changes were minimized when acidic citrate dextrose was used as an anticoagulant and were abolished when blood samples were immediately placed on crushed ice, independently of the anticoagulant. Storage of plasma for 72h at room temperature induced a small (≅6%), but significant, decrease in cysteine when blood was collected in ethylenediaminetetraacetic tripotassium salt. In contrast, homocysteine was stable in plasma for 72h, independently of the anticoagulant used. In conclusion, if blood samples for plasma total homocysteine and cysteine measurement cannot be kept on ice, they should be collected in acidic citrate dextrose to minimize the artifactual changes.
Anti-nucleosome, anti-chromatin, anti-dsDNA and anti-histone antibody reactivity in systemic lupus erythematosus
Authors: González Concepción , Garcia-Berrocal Belen , Herráez Oscar , Navajo José Alejandro , ManuelGonzález-Buitrago José 
Published: August 2004

AbstractAnti-nucleosome (anti-chromatin) antibodies play a key role in the pathogenesis of systemic lupus erythematosus (SLE). The objective of the present study was to determine the clinical significance of anti-nucleosome (anti-chromatin) antibodies, anti-dsDNA antibodies and anti-histone antibodies in patients with SLE in relation to patients with positive nuclear antibodies and healthy controls. We measured anti-nucleosome (anti-chromatin) antibodies, anti-dsDNA antibodies and anti-histone antibodies in 70 patients with SLE, 35 antinuclear antibody (ANA)-positive subjects without autoimmune disease and 35 blood donors. All antibodies were determined by enzyme-linked immunosorbent assay (ELISA). We obtained the receiver operating caracteristic (ROC) curve and the area under the curve (AUC) for each autoantibody. Likewise, we obtained the sensitivity, specificity and positive and negative likelihood ratios for each autoantibody. The highest AUC was obtained for anti-nucleosome (0.898) and the lowest AUC for a kit for anti-dsDNA (0.725). Stratification of the control group (ANA-positive subjects without autoimmune disease and blood donors) produced significant changes in the AUCs; all AUCs decreased when ANA-positive patients without autoimmune disease were considered as controls and all AUCs increased when blood donors were considered as controls. These effects were less marked in anti-dsDNA antibodies. We observed discrepancies between kits (anti-nucleosome and anti-chromatin and two for anti-dsDNA). The highest sensitivity for SLE was obtained for anti-nucleosome antibodies (86%) and the highest specificity was obtained for anti-dsDNA antibodies (90%). In conclusion, anti-nucleosome and anti-chromatin kits show different degrees of clinical accuracy due to the cut-off selected by the manufacturer. Once the kits with the best performance and the optimal cut-offs have been selected, anti-nucleosome antibodies and anti-dsDNA antibodies provide similar information in established SLE.
Age dependence of serum β-N-acetylhexosaminidase (NAG) activity
Authors: Oláh Anna V. , Price Robert G. , Csáthy László , Országh Éva , Oláh Éva , Varga József 
Published: August 2004

AbstractSerum N-acetyl-β-D-glucosaminidase (NAG; EC 3.2.1.30) is a hexosaminidase and may be a predictor of vascular injury, e.g., in infant respiratory distress syndrome, pneumonia, broncho-pulmonary dysplasia and necrotizing enterocolitis. To estimate the new diagnostic prospects we have modified our urinary NAG assay. In this sensitive colorimetric micro-assay, VRA-GlcNAc was used as a substrate. In the present study the age dependence of serum NAG activity was investigated in newborn babies, infants (1–24 months), children (2–18 years) and adults (19–80 years). Serum NAG activity was found to be age-dependent; it is higher in early childhood (11–59 U/l) but decreases to a constant value at the age of 1–2 years. After the age of 2 years it is similar to adults' NAG (10–30 U/l). In pediatrics age-matched reference ranges must be taken into consideration.
Near-patient testing for infection using urinalysis and immuno-chromatography strips
Authors: Pugia Michael J. , Sommer Ronald G. , Kuo Hai-Hang , Corey Paul F. , Gopual Darryl L. , Lott John A. 
Published: August 2004

AbstractUrinary tract infections require costly confirmatory tests such as a urine culture to establish the diagnosis. Elimination of the culture step would save resources; diagnosis and treatment could begin in hours rather than days. We tested a new dip-and-read strip that uses immuno-chromatography (IC) to detect infectious agents in urine. We used a goat-derived polyclonal antibody with reactivity to the cell-wall proteins of
Generation of eight adjacent mutations in a single step using a site-directed mutagenesis kit
Authors: Cabré Anna , Girona Josefa , Zalba Guillermo , Moreno María-Ujué , Díez Javier , Masana Lluís 
Published: August 2004

AbstractStudies that characterize transcriptional regulatory elements involve the site-directed mutagenesis methodology to generate deletions, insertions and point mutations. Commercial PCR-based system kits are widely used to introduce up to four base changes in a target sequence. Sequential mutagenesis experiments allow more than four bases to be altered. In this work, we show that the QuikChange site-directed mutagenesis kit developed by Stratagene, with an optimum primer design, can change eight adjacent bases. This approach allows us to study the effect of DNA sequence changes on functionality of specific sequences from gene target regions, including promoters, exons and introns. As a result of this methodology, a faster and cheaper way of introducing this number of mutations is achieved in a single step with only one pair of primers, thus reducing the possibility of potential random mutation in the rest of the target sequence.
Comparison of three commercial assays for the measurement of 17α-hydroxyprogesterone (17α-OHPR): limitations of the quality control system
Authors: Meier Ursula , Schnabel Claudia , Kunz Dagmar , Driesch Reinhard , Gressner Axel M. 
Published: August 2004

AbstractThe measurement of 17α-hydroxyprogesterone (17α-OHPR) is of value for the diagnosis and management of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. In the central laboratory from 2000 to 2002, we observed, using the assay from the manufacturer DSL, an elevation of the moving average of 17α-OHPR concentrations and a number of adrenocorticotropic hormone (ACTH) stimulation tests despite the lack of any changes to the internal and external quality control, of which the criteria were continuously fulfilled. We studied a population of n=49 patients for the measurement of 17α-OHPR, with and without extraction, to evaluate the quality of different commercially available radioimmunoassays. The internal and external quality controls were successful in determining 17α-OHPR. An excellent measurement and correlation of 17α-OHPR was expressed with the assay from the manufacturer IBL without extraction and from the manufacturer DSL with extraction. The quantitative determination of 17α-OHPR requires adequate specificity and accuracy of the 17α-OHPR radioimmunoassays. The results show that internal and external quality control systems are not sufficient to resolve analytical problems described in this study.
Analysis of candidate genes in Polish families with obesity
Authors: Malczewska-Malec Malgorzata , Wybranska Iwona , Leszczynska-Golabek Iwona , Partyka Lukasz , Hartwich Jadwiga , Jabrocka Agata , Kiec-Wilk Beata , Kwasniak Malgorzata , Motyka Marcin , Dembinska-Kiec Aldona 
Published: August 2004

AbstractThis study analyzes the relationship between risk factors related to overweight/obesity, insulin resistance, lipid tolerance, hypertension, endothelial function and genetic polymorphisms associated with: i) appetite regulation (leptin, melanocortin-3-receptor (MCR-3), dopamine receptor 2 (D2R)); ii) adipocyte differentiation and insulin sensitivity (peroxisome proliferator-activated receptor-γThe 122 members of 40 obese Caucasian families from southern Poland participated in the study. The genotypes were analyzed by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) or by direct sequencing. Phenotypes related to obesity (body mass index (BMI), fat/lean body mass composition, waist-to-hip ratio (WHR)), fasting lipids, glucose, leptin and insulin, as well as insulin during oral glucose tolerance test (OGTT) (4 points within 2 hours) and during oral lipid tolerance test (OLTT) (5 points within 8 hours) were assessed. The insulin sensitivity indexes: homeostasis model assessment of insulin resistance, whole body insulin sensitivity index, hepatic insulin sensitivity and early secretory response to an oral glucose load (HOMA-IR, ISI-COMP, ISI-HOMA and DELTA) were calculated.The single gene mutations such as CWe conclude that the polymorphisms we investigated were weakly correlated with obesity but significantly modified the risk factors of the metabolic syndrome.
Detection of the Arg702Trp, Gly908Arg and Leu1007fsinsC polymorphisms of the NOD2/CARD15 gene by real-time PCR with melting curve analysis
Authors: Rüegg Christian , Hersberger Martin , Wusk Barbara , Rentsch Katharina , Kullak-Ublick Gerd A. , Eckardstein Arnold von , Maly Friedrich E. 
Published: August 2004

AbstractCrohn's disease is a complex disorder, with multiple genetic traits. A frameshift mutation (Leu1007fsinsC) and two missense mutations (Gly908Arg and Arg702Trp) in the NOD2/CARD15 gene are strongly associated with susceptibility to Crohn's disease. The presence of one of these risk alleles confers a 2- to 4-fold increase in the risk of developing Crohn's disease, and the presence of two mutant alleles increases the risk over 20-fold.To facilitate the analysis of these polymorphisms, we developed three LightCycler assays to detect the missense mutations Arg702Trp and Gly908Arg and the frameshift mutation Leu100fsinsC in the
Moderate exercise with a dietary vitamin C and E combination protects against streptozotocin-induced oxidative damage to the blood and improves fetal outcomes in pregnant rats
Authors: Naziroğlu Mustafa , Şimşek Mehmet , Kutlu Mehmet 
Published: August 2004

AbstractA considerable amount of clinical and experimental evidence now exists suggesting that many biochemical pathways strictly associated with diabetes increase the production of reactive oxygen species (ROS). However, daily moderate exercise and vitamins C and E(VCE ) supplementation can be beneficial to diabetes due to reducing blood glucose and free radical production. In the present study, we investigated the effect of VCE and moderate exercise on lipid peroxidation (MDA) and scavenging enzyme activity in the blood of STZ-induced diabetic pregnant rats.Fifty female Wistar rats were used and were randomly divided into five groups. The first and second were used as the control and pregnant control groups, respectively. The third group was the pregnant diabetic group. The fourth group was the diabetic-pregnant-exercise group. VCE-supplemented feed was given to pregnant-diabetic-exercise rats constituting the fifth group. Animals in the exercised groups were moderately exercised daily on a treadmill (16.1 m/min, 45 min/d) for three weeks (five days a week). Diabetes was induced on day zero of the study. Body weights in the five groups were recorded weekly. Plasma and red blood cell (RBC) samples were taken from all animals on day 20.Glutathione peroxidase (GSH-Px), catalase and reduced glutathione (GSH) levels in plasma and RBCs, glucose, vitamins A, E and β-carotene in plasma, the number of fetuses, and body weight were lower in pregnant diabetic rats than in control animals, whereas there was a significant increase in platelet counts and plasma and RBC MDA levels. The decreased antioxidant enzymes did not improve through exercise only. However, the decreased vitamins, and increased MDA, glucose levels and white blood cell (WBC) counts were improved either by exercise or exercise plus VCE supplementation. There were no significant changes in the RBC counts and hemoglobin values in the five groups.In conclusion, these data demonstrate that there is an increase in MDA in the blood of diabetic pregnant animals, whereas there is a decrease in the number of fetuses, antioxidant vitamins and enzymes. However, dietary VCE with moderate exercise may strengthen the antioxidant defense system due to reducing ROS. They may play a role in preventing diabetes-related diseases of pregnant subjects.
An International Standard for whole blood folate: evaluation of a lyophilised haemolysate in an international collaborative study
Authors: Thorpe Susan J. , Sands Dawn , Heath Alan B. , Hamilton Malcolm S. , Blackmore Sheena , Barrowcliffe Trevor 
Published: August 2004

AbstractFolate measurements, particularly for whole blood, show wide inter-laboratory and inter-methodology variability. This variability appears to be due in part to the lack of internationally accepted reference materials. A whole blood haemolysate, lyophilised in ampoules and designated 95/528, was therefore evaluated by 15 laboratories in five countries for its suitability as an International Standard (IS) for whole blood folate. The preparation was assayed using a variety of microbiological and protein-binding methodologies against local standards and calibrators. A consensus folate content was assigned to 95/528. The inclusion of three whole blood samples in the study with widely differing folate levels demonstrated a considerable reduction in inter-laboratory variability when the folate content of the samples was determined relative to the proposed IS 95/528 rather than to laboratories' local standards and calibrators. Accelerated degradation studies indicated that the folate content of 95/528 is stable when stored at −20°C. On the basis of the results presented here, the World Health Organization Expert Committee on Biological Standardization established 95/528 as an IS for whole blood folate.
Population-specific reference values for thyroid hormones on the Abbott ARCHITECT i2000 analyzer
Authors: González-Sagrado Manuel , Martín-Gil Francisco Javier 
Published: August 2004

AbstractReliable reference ranges are important in the interpretation of laboratory data, and it is incumbent on each laboratory to verify that the ranges they use are appropriate for the patient population they serve. The objective of this study was to determine population-specific reference ranges for thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3) and total triiodothyronine (TT3) on the Abbott ARCHITECT
Pitfalls and drawbacks in screening of congenital disorders of glycosylation
Authors: Marklová Eliška , Albahri Ziad 
Published: August 2004

AbstractCongenital disorders of glycosylation include a group of diseases, each of them caused by different protein (mostly enzyme) impairment due to a specific gene defect. The many subtypes are classified according to clinical features, enzymology and molecular genetic analyses. Problems in diagnostics arise from the great diversity in clinical presentation, usually age-related, and different severities of individual types of these, by far underdiagnosed, diseases. Also the biochemical findings tend to vary, even within a single type. No one screening test, common for all types, is available so far. Several methods of choice may be used in the first approach; other procedures must follow for detailed typing of the defect. Possible drawbacks and pitfalls in the diagnostics from the viewpoint of our 3-year studies and practical screening experience are presented.
Rapid generation of detailed loss of heterozygosity profiles for routine diagnosis of gliomas
Authors: Beetz Christian , Hartmann Armin , Kiehntopf Michael , Wölfl Stefan , Kalff Rolf , Deufel Thomas , Patt Stephan 
Published: August 2004

AbstractAberrations in the genomes of gliomas seem to correlate well with clinical parameters. Pertinent studies, however, rely on highly sophisticated methods, they require large amounts of high-quality sample material and/or they demand profound analytical expertise. Consequently, molecular tumour analysis has not yet been widely implemented in routine laboratory applications. We have developed an easy-to-perform approach for the rapid derivation of a detailed lossof-heterozygosity profile from individual gliomas. DNA of PCR quality is extracted in a one-step procedure from routinely obtained material. A microsatellite-based marker set is used to detect the deletion status of genomic regions (i) with established diagnostic relevance, (ii) recurrently found deleted in gliomas, or (iii) generally associated with tumour suppressor activity. The complete profile comprises 25 regions and is generated from 64 markers multiplexed into 18 reactions. Illustratively, we present findings from an anaplastic oligodendroglioma; the molecular data for this tumour allow refined diagnostic and prognostic statements that could not be derived from histology alone. Our approach should prove useful in the routine diagnosis of gliomas. Simultaneously, research data for many highly relevant regions are generated in a comparatively simple and inexpensive way.
Urine labeling with orally applied marker substances in drug substitution therapy
Authors: Huppertz Bernd , Gauchel Gisela , Feiertag Heribert , Schweizer Hermann , Krieger Horst , Richter Francois , Heinz Helmut , Blanke Joerg , Gastpar Markus , Keller Ruprecht 
Published: August 2004

AbstractThe compliance of 581 drug addicts attending six methadone substitution outpatient clinics was determined over a period of 18 months. Urine from these patients was labeled following oral administration of low molecular weight polyethylene glycols as marker substances. These substances were measured in approx. 5800 urine samples. A protocol for applying marker substances and ways to prevent substitution of urine samples were evaluated. Normal values for marker substances in urine were determined. The results suggest that this labeling procedure is a new diagnostictool to prevent manipulation of urine samples by drug addicts receiving substitution therapy.
Cardiac natriuretic hormones, neuro-hormones, thyroid hormones and cytokines in normal subjects and patients with heart failure
Authors: Emdin Michele , Passino Claudio , Prontera Concetta , Iervasi Annalisa , Ripoli Andrea , Masini Silvano , Zucchelli Gian Carlo , Clerico Aldo 
Published: August 2004

AbstractThe derangement of neuro-endocrine control of circulation influences both disease evolution and response to treatment in patients with heart failure, but little data are available about the complex relationships between the degree of neuro-hormonal activation and clinical severity. We studied the relationships between cardiac natriuretic hormones (CNHs) and several neuro-hormones and immunological markers in a prospective cohort of 105 consecutive patients with cardiomyopathy (77 men and 28 women, mean age 66.7±12.4 years, range 33–89 years). We assayed the circulating levels of CNHs (atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)), plasma renin activity (PRA), aldosterone, cortisol, adrenaline, noradrenaline, thyroid hormones and thyroid stimulating hormone (TSH), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The concentrations of all CNHs and neuro-hormones were higher in patients with heart failure compared to normal subjects, except for free triiodothyronine (FT3), which was below normal values. ANP was positively related to NYHA class, IL-6, adrenaline, noradrenaline and cortisol, while negatively with ejection fraction and FT3. BNP was positively related to age, NYHA class, IL-6, TNF-α, adrenaline, noradrenaline and cortisol, while negatively with ejection fraction and FT3. A stepwise multiple linear regression indicated that plasma ANP depended only on ejection fraction, adrenaline and noradrenaline values, while for plasma BNP variation NYHA class contributed too. Our data confirm a progressive activation of hormonal and immunological systems in patients with heart failure. Furthermore, CNH circulating levels in heart failure are affected not only by cardiac function and disease severity, but also by activation of neuro-hormonal and stress-related cytokine systems, as well as by the thyroid hormones, even on usual medical treatment.