bluuebunny/crossref_metadata_2025 huggingface dataset:
Preliminary Evaluation of the New Hematology Analyzer COULTER® GEN•S™ in a University Hospital
Authors: Picard Françoise , Gicquel Catherine , Marnet Laurence , Guesnu Martine , Levy Jean P.
Published: October 2004

The COULTER® GEN·S™ system (COULTER® Corp, Miami, USA) is an automated hematology instrument that is designed to provide a complete hematological profile including white blood cells (WBC), complete blood count (CBC) differential count (diff) and the reticulocyte parameters. It was evaluated in our laboratory over a one month period. A preliminary study was performed using the GEN·S™ software revision 1D. The evaluation had two purposes: 1) evaluation of the GEN·S™ specifications; 2) comparison of its analytical performance with the hematology analyzer currently used in our laboratory.

The first part of the evaluation showed that the COULTER® GEN·S™ is reproducible, has linearity beyond the specifications given by the manufacturer and produces stable results up to 48 hours after blood collection.

The evaluation of analytical performance included: 1) a comparison between the GEN·S™ CBC and diff numerical results and the COULTER® STKS™ (COULTER® Corp, Miami, USA). These comparisons showed that the results given by the two methods are similar and suggested that the COULTER® GEN·S™ could replace the current hematology instrument in use in our laboratory; 2) a performance analysis, to measure the system's ability to detect morphologic abnormalities, when compared to the reference blood smear examination. This part of the evaluation was performed on both normal and abnormal samples. The results of this analysis showed that the sensitivity of the GEN·S™ was excellent, especially regarding blast cells, immature granulocytes, nucleated red blood cells (NRBCs) and platelet clumps when using the complete suspect flagging system of the instrument. In addition, the use of the review criteria in our laboratory allowed to detect all hematological diseases. The overall false negative rate was 0.9 %.

Thus we consider that the COULTER® GEN·S™ system is suited for use in medium-to large hospital laboratories which perform more than 100 CBC/day. Overall, the instrument had excellent performance, with a throughput of more than 100 samples/h. Its user friendly workstation has complete patient data management, which is in compliance with good laboratory practices in France.
Use of Biochemical Markers in Acute Coronary Syndromes. IFCC Scientific Division, Committee on Standardization of Markers of Cardiac Damage
Authors: Panteghini Mauro , Apple Fred S. , Christenson Robert H. , Dati Francesco , Mair Johannes , Wu Alan H.
Published: October 2004

This paper presents evidence and suggestions from the IFCC Committee on “Standardization of Markers of Cardiac Damage” (C-SMCD) on the use of biochemical markers for the triage diagnosis of acute coronary syndromes. There is general agreement that both ‘early’ and ‘definitive’ biochemical markers of myocardial damage are necessary and that these assays must be available with a turnaround time of 1 h or less. Currently, myoglobin is the marker that most effectively fits the role as an ‘early’ marker, whereas ‘definitive’ markers are cardiac troponins. Since the sensitivity of the initial electrocardiogram is only 50 % for detecting myocardial infarction, the use of biochemical markers may significantly contribute to the early diagnosis and become relevant when the electrocardiogram is not diagnostic. In addition, new sensitive biochemical markers, particularly the cardiac troponins, are presently the best to detect the presence of minor myocardial cell damage. With regard to this, two decision limits are probably needed for the optimal use of troponins: a low abnormal value suggesting the presence of myocardial damage and a higher value suggesting the diagnosis of myocardial infarction according to traditionally used criteria. Properly designed studies should be performed to establish limits for each commercially available troponin assay. Finally, it is recognized that there is no need for the use of any biochemical marker when the clinical diagnosis is unequivocal, other than for diagnosing reinfarction, estimating the infarct size, and monitoring thrombolytic therapy.
Regulation of Lipid and Lipoprotein Metabolism by PPAR Activators
Authors: Gervois Philippe , Torra Inés Pineda , Fruchart Jean-Charles , Staels Bart
Published: October 2004

The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear hormone receptor superfamily. PPARα, the first identified PPAR family member, is principally expressed in tissues exhibiting high rates of β-oxidation such as liver, kidney, heart and muscle. PPARγ, on the other hand, is expressed at high levels in adipose tissue. PPARs are activated by dietary fatty acids and eicosanoids, as well as by pharmacological drugs, such as fibrates for PPARα and glitazones for PPARγ. PPARα mediates the hypolipidemic action of fibrates in the treatment of hypertriglyceridemia and hypoalphalipoproteinemia. PPARα is considered a major regulator of intra- and extracellular lipid metabolism. Upon fibrate activation, PPARα down-regulates hepatic apolipoprotein C-III and increases lipoprotein lipase gene expression, key players in triglyceride metabolism. In addition, PPARα activation increases plasma HDL cholesterol via the induction of hepatic apolipoprotein A-I and apolipoprotein A-II expression in humans. Glitazones exert a hypotriglyceridemic action via PPARγ-mediated induction of lipoprotein lipase expression in adipose tissue. PPARs play also a role in intracellular lipid metabolism by up-regulating the expression of enzymes involved in conversion of fatty acids in acyl-coenzyme A esters, fatty acid entry into mitochondria and peroxisomal and mitochondrial fatty acid catabolism. These observations have provided the molecular basis leading to a better understanding of the mechanism of action of fibrates and glitazones on lipid and lipoprotein metabolism and identify PPARs as attractive targets for the rational design of more potent lipid-lowering drugs.
Laboratory Screening for Erythropoietin Abuse in Sport: an Emerging Challenge
Authors: Lippi Giuseppe , Guidi Giancesare
Published: October 2004

The growing diffusion of banned practice to improve the athletic performances is forcing clinical laboratories to identify and standardize reliable assays to detect potential unfairness. Among the doping practices, the use of recombinant human erythropoietin is becoming fairly popular, due to simplicity and safeties of administration and troublesome detection. The heterogeneous response rate, the presence of a little but significant amount of naturally occurring hormone, the short half-life exhibited by recombinant human erythropoietin and the lack of standardization of commercial assays appear the main problems to overcome. Aim of the present article is to provide a critical review of some of the more widespread laboratory techniques currently available for the screening for erythropoietin abuse in sport.
Enzyme Immunoassays for Fragments (Epitopes) of Human Proatrial Natriuretic Peptides
Authors: Hartter Engelbert , Khalafpour Shiva , Mißbichler Albert , Hawa Gerhard , Woloszczuk Wolfgang
Published: October 2004

Several peptides derived from the N-terminal sequence of pro-atrial natriuretic peptide (proANP) have been tested successfully as markers of heart disease. We have developed specific and sensitive competitive enzyme immunoassays for fragments [1–30] and [31–67] of proANP. Antisera were raised in sheep against synthetic peptides predicted to be highly immunogenic. Binding specificity was determined by epitope mapping. Microtiter plates were coated with antibody specific for the Fc region of sheep IgG to capture the affinity-purified specific anti-proANP antibodies in an oriented and reproducible form. Synthetic proANP calibrators or diluted samples were incubated simultaneously with biotinylated peptide and binding was quantitated using streptavidin-peroxidase and TMB. Immunoreactive proANP could be measured in diluted plasma, serum and urine. The detection limits of the proANP[1–30] and proANP[31–67] assays were 2.5 and 10 pmol/l respectively. The linearity of samples diluted beyond the recommended assay conditions was good. Recoveries of added standard peptides ranged from 102 to 112%. Circulating concentrations of immunoreactive proANP in 115 healthy subjects ranged from 0.11 to 0.47 nmol/l proANP[1–30] and 0.18 to 0.79 nmol/l proANP[31–67]. In patients with cardiac disease, proANP levels were increased significantly. The reference interval of proANP[31–67] in urine was 0.09 to 1.7 nmol/l, several-fold higher than proANP[1–30] (<0.03 to 1.1 nmol/l). After storage for 6 months at −20°C there was no detectable decrease in immunoreactivity.
Transient Nature of Interference Effects from Heterophile Antibodies: Examples of Interference with Cardiac Marker Measurements
Authors: Kazmierczak Steven C. , Catrou Paul G. , Briley Kimberly P.
Published: October 2004

Two-site immunoassay methods have become the standard technique for measurement of a wide variety of drugs, hormones, and cell proteins. One limitation of these methods is their susceptibility to interference from heterophilic antibodies present in the sera of some patients. Human anti-murine antibodies represent a common heterophile antibody that can bind to mouse immunoglobulin and as well as to immunoglobulin from other species. While the mechanism of human anti-murine antibody interference has been well characterized, the time course over which this interference occurs and the susceptibility of different immunoassay procedures to human anti-murine antibody interference from patients with human anti-murine antibody have not been as well described. We report on the time course of interference in assays for cardiac markers for two patients with human anti-murine antibodies. We measured creatine kinase MB isoenzyme (CKMB) and troponins I and T using three different vendors' immunoassay procedures. Our results demonstrate that assay interference due to human anti-murine antibody interference is a transient phenomenon. In one of our patients, human anti-murine antibody interference appeared suddenly, peaked approximately 9 days following its appearance, and gradually resolved over the next 3 weeks. In addition, we found that immunoassay methods from different vendors can show highly variable interference effects when human anti-murine antibody-containing specimens are analyzed.
Changes in Bone Turnover and Deoxypyridinoline Levels in Epileptic Patients
Authors: Telci Aysegül , Çakatay Ufuk , Kurt Betül Baykan , Kayali Refik , Sivas Ahmet , Akçay Tülay , Gökyiğit Aysen
Published: October 2004

In this study, we evaluated bone turnover in 52 epileptic patients receiving chronic anticonvulsant therapy and in 39 healthy volunteers whose ages matched those of the patients. We determined serum osteocalcin and total and bone alkaline phosphatase levels as markers of bone formation, and urinary deoxypyridinoline and urinary calcium levels as markers of bone resorption. Statistical comparison of the levels of these markers between sexes in epileptic patients and their control groups revealed that total alkaline phosphatase levels were significantly increased in patients from both sexes compared with those of their controls. Urinary deoxypyridinoline levels of male epileptic patients were significantly increased compared with those of their controls. On the other hand, 25-hydroxyvitamin D levels of the male patients were significantly reduced compared with those of their controls. Serum osteocalcin, bone alkaline phosphatase, and urinary calcium levels of epileptic patients were not statistically different from those of the controls. We found that urinary deoxypyridinoline levels of male epileptic patients were increased, however, we observed no difference in serum osteocalcin and bone alkaline phosphatase levels. The lack of difference may be attributed to the fact that only the resorption phase of bone turnover is affected during chronic anticonvulsant therapy.
Markers of Endothelial Dysfunction
Authors: Müller Mathias M. , Griesmacher Andrea
Published: October 2004

The endothelium is a functional barrier between vessel wall and blood stream. Assuming the total human vascular and capillary system occupies a surface area of more than 1,000 m2which is covered by 1013endothelial cells, the complex role of the endothelium for hemostasis and immunological and metabolic processes becomes obvious. Dysfunction of the endothelium is a critical factor in the pathogenesis of vascular diseases and thrombus formation.

This paper provides a brief review of physiological endothelial functions and summarizes measurable changes in products released from endothelial cells under pathological conditions which were associated with endothelial dysfunction.
Standardization and Quality Control of PCR Analyses
Authors: Burkardt Hans-Joachim
Published: October 2004

In the very beginning of polymerase chain reaction (PCR) tests entering the field of diagnosis of infectious agents, the introduction of this technology into routine diagnosis was hampered by its frequent tendency to create false-positive results because of contamination. This problem is now widely solved by the introduction of the uracil-N-glycosylase (UNG) anticontamination technology. However, care must still be taken to avoid other sources of producing false positive results. They might additionally derive from human error and/or insufficient PCR amplification and detection protocols. A special case lies in the fact that PCR also amplifies DNA from dead organisms rendering a result diagnostically correct as positive, but clinically as false-positive. In PCR, as in any other diagnostic test, the risk of creating a false-negative result also exists. In such a case, the most probable source besides human error, low target or poor amplification and detection protocols is an inhibition caused by interfering substances in a patient's sample. Strategies to recognize and overcome this issue are discussed in this article. Finally a few results from quality control studies on amplification technologies in the diagnosis of infectious agents are reviewed.
Histochemical and Immunocytochemical Approaches to the Study of Oxidative Stress
Authors: Raina Arun K. , Perry George , Nunomura Akihiko , Sayre Lawrence M. , Smith Mark A.
Published: October 2004

We review an array of newly developed in situ detection methods that can be used for the qualitative and semi-quantitative measurement of various indices related to oxidative stress. The importance of in situ methods over bulk analysis cannot be overstated when considering the structural and cellular complexity of tissue and the effects of diseases thereof. Indeed, in situ detection allows detection of specific cell types affected or specific localization such that a process affecting only a small fraction of the tissue or cells can be readily visualized. Consequently, a positive signal in situ indicates real levels that cannot be masked by unrelated or compensatory responses in adjacent cells, and corrections can be easily made for the modifications to long-lived proteins during physiological aging. In fact, the damage to extracellular matrix proteins of major vessels, provides a cumulative record of long-term oxidative insult. Yet the same properties that make vessels ideal markers for aging limits their sensitivity to detect disease-specific changes unless in situ techniques are used.
Sniffing out the Truth: Clinical Diagnosis Using the Electronic Nose
Authors: Pavlou A.K. , Turner A.P.F.
Published: October 2004

Recently the use of smell in clinical diagnosis has been rediscovered due to major advances in odour sensing technology and artificial intelligence (AI). It was well known in the past that a number of infectious or metabolic diseases could liberate specific odours characteristic of the disease stage. Later chromatographic techniques identified an enormous number of volatiles in human clinical specimens that might serve as potential disease markers. “Artificial nose” technology has been employed in several areas of medical diagnosis, including rapid detection of tuberculosis (TB),Helicobacter pylori(HP) and urinary tract infections (UTI). Preliminary results have demonstrated the possibility of identifying and characterising microbial pathogens in clinical specimens. A hybrid intelligent model of four interdependent “tools”, odour generation “kits”, rapid volatile delivery and recovery systems, consistent low drift sensor performance and a hybrid intelligent system of parallel neural networks (NN) and expert systems, have been applied in gastric, pulmonary and urine diagnosis. Initial clinical tests have shown that it may be possible in the near future to use electronic nose technology not only for the rapid detection of diseases such as peptic ulceration, UTI, and TB but also for the continuous dynamic monitoring of disease stages. Major advances in information and gas sensor technology could enhance the diagnostic power of future bio-electronic noses and facilitate global surveillance models of disease control and management.
Oncogenes and Thyroid Cancer
Authors: Vecchio Giancarlo , Santoro Massimo
Published: October 2004

Human thyroid tumors can be derived either from epithelial follicular cells or from parafollicular C-cells. Follicular cell-derived tumors represent a wide spectrum of lesions, ranging from benign adenomas through differentiated (follicular and papillary) and undifferentiated (anaplastic) carcinomas, thus providing a good model for finding a correlation between specific genetic lesions and histologic phenotype. Follicular adenomas and carcinomas show frequently the presence of mutations in one of the three ras genes. Papillary carcinomas show frequently a specific gene rearrangement which gives rise to the formation of several types of so-called RET/PTC chimeric genes. This lesions occur in almost 50% of papillary cancers and consist in the juxtaposition of the 3′ or tyrosine kinase domain of the RET gene (which codes for a receptor protein not normally expressed in follicular thyroid cells) with the 5′ domain of ubiquitously expressed genes, which provide the promoter and dimerization functions, necessary for the constitutive activation of RET/PTC proteins. Anaplastic carcinomas are frequently associated with mutations of the p53 tumor suppressor. Finally, point mutations of the RET gene are found in familial endocrine syndromes (FMTC; MEN2A and MEN2B), a common feature of which is the medullary thyroid carcinoma, a malignant tumor derived from parafollicular C-cells.
Paraneoplastic Syndromes of the Nervous System
Authors: Posner Jerome B. , Dalmau Josep O.
Published: October 2004

Paraneoplastic syndromes affecting the nervous system are unique among immune-mediated disorders in that the trigger of the immune response is known: tumor expression of proteins normally restricted to neurons (or other immunoprivileged sites, such as testis) but ectopically expressed in some cancers results in an immunological response characterized by high titers of antibodies targeting the “onconeuronal” antigen. A T-cell response is also elicited in some paraneoplastic syndromes and may be the cause of neuronal destruction. In some instances genes that code for the antigens recognized by the autoantibodies have been identified, cloned and sequenced. Some of the proteins so identified are RNA binding proteins but their specific function has not been identified. In some individuals with cancer but no paraneoplastic syndrome, low titers of antibody can be identified in the serum. Low titers of antibody are associated with a better prognosis of the cancer. Experimental animals immunized against a paraneoplastic antigen are partially protected against tumors that express that antigen.
Genetic Modifying Factors in β-Thalassemia
Authors: Cao Antonio , Moi Paolo
Published: October 2004

The β-thalassemia is probably the most extensively studied genetic disease. Essentially any molecular defect that has been first described in association with the globin genes has been later implicated as a molecular determinant of newly discovered genes. Accordingly, the thalassemias have always represented a model genetic disease, especially in relation to the development of programs for population screening, genetic counseling and prenatal diagnosis. Here we will review the present knowledge on the genetics of thalassemia and of the relevant modifying factors. Major categories of the carrier state, the genotypes, the clinical phenotypes and the correlation between genotype and phenotype will be discussed.
The Genetics of Multiple Sclerosis
Authors: Compston Alastair
Published: October 2004

Classical genetic studies involving the analysis of pedigrees and recurrence risk within families have defined the extent to which genetic factors contribute to the aetiology of multiple sclerosis. Limited progress has been made in identifying the number and topography of genetic loci contributing to susceptibility through molecular investigation either of candidate genes or the whole genome using microsatellite and single nucleotide polymorphisms.
Ribozyme Gene Therapy for Autosomal Dominant Retinal Disease
Authors: Hauswirth William W. , LaVail Matthew M. , Flannery John G. , Lewin Alfred S.
Published: October 2004

Gene delivery to cells of the retina, particularly to photoreceptor cells, has broad potential both for answering basic questions of retinal biology and for more applied therapeutic purposes. The use of ribozymes as therapy for autosomal dominant retinal diseases is a promising technique, and the theoretical and practical basis for their use is discussed. The process involves designing and testing ribozymes first in vitro and then in animal models of retinal disease. Viral vectors based on the nonpathogenic human adeno-associated virus, when coupled with the strong, rod photoreceptor specific opsin promoter, offer an efficient and nontoxic way to deliver and express ribozymes in photoreceptor cells for long time periods of time. Effective ribozyme-mediated therapy also demands careful in vitro analysis of a ribozyme's ability to efficiently and specifically distinguish between mutant and wild type RNAs. Finally, effective demonstration of therapy in an animal model requires careful analysis of any rescue effect in the retina using multiple criteria, including biochemical, structural and physiological assays. For this purpose, ribozyme therapy in a transgenic rat model of retinitis pigmentosa containing a dominant rod opsin mutation (proline-to-histidine change at position 23) is discussed in detail.
Oxidized Lipoproteins and Endothelium
Authors: Pirillo Angela , Zhu Weimin , Norata Giuseppe D. , Zanelli Tiziano , Barberi Laura , Roma Paola , Catapano Alberico L.
Published: October 2004

Endothelium is an early target of pro-atherosclerotic events, which may result in functional and morphological perturbations. Oxidized low density lipoproteins, an atherogenic factor with strong cytotoxicity, may potentially contribute to altered endothelial function through the activation of a stress response, which would rescue cells to full vitality, or, conversely, by leading to cell death. Evidence is presented here for the ability of chemically oxidized low density lipoproteins to induce the synthesis of the inducible form of heat shock protein 70 in cultured human endothelial cells, and for the association of epitopes of these modified lipoproteins with apoptotic endothelial cells in aortic sections from hypercholesterolemic rabbits.
Experiences with External Quality Assessment (EQA) in Molecular Diagnostics in Clinical Laboratories in Germany
Authors: Neumaier Michael , Braun Andreas , Gessner Reinhard , Funke Harald
Published: October 2004

The German Societies for Clinical Chemistry (DGKC) and Laboratory Medicine (DGLM) have established an official working group on molecular diagnostics in the field of laboratory medicine. The group's objectives are to support the establishment of molecular biology methods for the use in diagnostics in German clinical laboratories. Towards this end, we have defined specific aims, which are 1) the implementation and extension of external quality assessment (EQA) schemes and methodological exercises offered to clinical diagnostic laboratories, 2) the establishment of a proficiency network and data base within the societies, 3) the implementation of an educational program in molecular diagnostic procedures for clinical chemists and laboratory physicians through the organisation of symposia and workshops and 4) the cooperation with other DGKC/DGLM working groups on shared aspects of laboratory analysis, e.g. preanalytics. The focus of this presentation is to introduce some of these goals in more detail with particular emphasis on the first two program aspects and to discuss experiences with these activities.
Unravelling Genetic Data by Arrayed Primer Extension
Authors: Tõnisson Neeme , Kurg Ants , Kaasik Krista , Lõhmussaar Elin , Metspalu Andres
Published: October 2004

We have developed a method for arrayed primer extension (APEX) on an oligonucleotide microchip together with the 4-color fluoresence imaging equipment and supporting software, that allows analysis of the DNA sequence and changes in it. Mutation analysis of BRCA1 gene and single nucleotide polymorphism (SNP) chip for genotyping were used as a model system. Chip surface chemistry, template preparation and APEX reaction conditions were optimised and the assay is ready to be implemented in variety of DNA analysis from SNP testing to DNA resequencing.
Laboratory Diagnosis of Patients with Acute Chest Pain
Authors: Penttilä Ilkka , Penttilä Karri , Rantanen Tapio
Published: October 2004

The enzyme activities of creatine kinase (CK), its isoenzyme MB (CK-MB) and of lactate dehydrogenase isoenzyme 1 (LD-1) have been used for years in diagnosing patients with chest pain in order to differentiate patients with acute myocardial infarction (AMI) from non-AMI patients. These methods are easy to perform as automated analyses, but they are not specific for cardiac muscle damage. During the early 90's the situation changed. First creatine kinase MB mass (CK-MB mass) replaced the measurement of CK-MB activity. Subsequently cardiac-specific proteins troponin T (cTnT) and troponin I (cTnI) appeared on the scene, displacing LD-1 analysis. However, troponin concentrations in blood increase only from four to six hours after onset of chest pain. Therefore a rapid marker such as myoglobin, fatty acid binding protein or glycogen phosphorylase BB could be used in early diagnosis of AMI. On the other hand, CK-MB isoforms alone may also be useful in rapid diagnosis of cardiac muscle damage. Myoglobin, CK-MB mass, cTnT and cTnI are nowadays widely used in diagnosing patients with acute chest pain. Myoglobin is not cardiac-specific and therefore requires supplementation with some other analyses such as troponins to support the myoglobin value. Troponins are very highly cardiac-specific. Only the sera of some patients with severe renal failure, which requires hemodialysis, have elevated cTnT and /or cTnI without there being any evidence of cardiac damage. On the other hand, the latest studies have shown that elevated troponin levels in sera of hemodialysis patients point to an increased risk of future cardiac events in a similar manner to the elevated troponin values in sera of patients with unstable angina pectoris. In addition, the bedside tests for cTnT and cTnI alone or together with myoglobin and CK-MB mass can be used instead of quantitative analyses in the diagnosis of patients with chest pain. These rapid tests are easy to perform and they do not require expensive instrumentation. For routine clinical laboratory practice we suggest that in diagnosis of patients with chest pain, myoglobin and CK-MB mass measurements should be performed whenever they are requested (24 h/day) and cTnT or cTnI on admission to the hospital and then 4–6 and 12 hours later.
Methods for the Determination of Plasma Total Homocysteine: a Review
Authors: Amores-Sánchez Maria Isabel , Medina Miguel Ángel
Published: October 2004

Total homocysteine is the sum of all homocysteine species present in plasma. This parameter is valuable for the diagnosis and follow up of cobalamine or folate deficiencies, and it has been accepted as an independent risk factor for premature cardiovascular disease. These reasons justify the introduction of total homocysteine assays in the routine clinical laboratory. In the present review, we discuss the procedures for sample collection, processing and storage, and review the methodologies for measuring total homocysteine. We compare their feasibility as routine methods in the clinical laboratory.
Serum Protein 90K/Mac-2BP Is an Independent Predictor of Disease Severity during Hepatitis C Virus Infection
Authors: Kittl Eva M. , Hofmann Jörg , Hartmann Gerold , Sebesta Christian , Beer Franz , Bauer Kurt , Huber Klaus R.
Published: October 2004

The serum protein designated 90K/Mac-2BP has been found at elevated concentrations in the sera of patients with various types of cancer and viral infections. The importance of the 90K/Mac-2BP serum concentrations in predicting the response towards interferon-α treatment for hepatitis C virus (HCV) infection prompted us to utilize a new ELISA for soluble human 90K/Mac-2BP to monitor the serum concentrations of this protein in our HCV-positive patients. Seventy HCV-PCR and anti-HCV antibody positive patients were analyzed for their serum levels of aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, cholinesterase, HCV-viral load, viral subtypes, and 90K/Mac-2BP. On correlation of age and 90K/Mac-2BP levels, we found an apparent correlation that was proved rather to be a strong dependence of 90K/Mac-2BP concentrations on disease severity/duration, which increases with age. Multiple correlation analysis demonstrated the independent nature of 90K/Mac-2BP concentrations, underscoring the potential high utility of this new marker. Our data corroborate the potential of the scavenger receptor family protein 90K/Mac-2BP as an independent predictor of disease severity during HCV infection.
Biochemical and Hematological Changes in Low-Level Aluminum Intoxication
Authors: González-Revaldería Joaquín , Casares Miguel , Paula Marta de , Pascual Tomás , Giner Vicente , Miravalles Elena
Published: October 2004

The aim of this study was to investigate the biochemical and hematological changes in patients on routine hemodialysis treatment when they were accidentally exposed to moderately high serum aluminum concentrations during a period of time of less than four months. We studied the changes in biochemical and hematological measurements in 33 patients on dialysis in our hospital before and during the exposure to about 0.85 μmol/l of aluminum in dialysis water due to a malfunction of the reverse osmosis system of water purification. Patients showed a decrease in the hemoglobin concentration from 115 ± 12.4 g/l to 108 ± 12.2 g/l (p=0.026) and in the mean corpuscular hemoglobin concentration from 5.15 ± 0.22 to 5.02 ± 0.30 mmol/l (p=0.014). Ferritin was decreased from 243 ± 192 μg/l to 196 ± 163 μg/l (p= 0.047) and transferrin saturation from 0.20 ± 0.06 to 0.15 ± 0.07 (p= 0.004). Biochemical measurements related to calcium-phosphate metabolism did not change. Otherwise, all patients showed an increase in serum aluminum from 0.56 ± 0.44 to 1.63 ± 0.52 μmol/l (p<0.001). No differences were detected in serum aluminum between patients receiving and not receiving oral aluminum salts. Even moderately high aluminum concentrations maintained during a short period of time could produce significant hematological alterations and a depletion of body iron stores before clinical manifestations were evident.
On Accuracy and Precision of a HPLC Method for Measurement of Urine Porphyrin Concentrations
Authors: Zuijderhoudt Floris M.J. , Koehorst Stephan G.A. , Kluitenberg Willem E. , Bok Jenneke Dorresteijn-de
Published: October 2004

We studied the accuracy and precision of a HPLC method for determination of porphyrins in urine. A commercial standard solution appeared to contain less porphyrins than indicated by the manufacturer, since calibration resulted in lower concentrations of uroporphyrin and coproporphyrin: 16% and 8%, respectively. Coefficients of variation for the measurement of uro-, hepta-, copro I and copro III porphyrins in samples of patients with and without porphyria were often much less than 15%. Comparison of measurements with and without calibrated standards revealed differences for uroporphyrin and coproporphyrin of 27% and 5%, respectively. Recovery of added uroporphyrin and coproporphyrin was 99%. The main cause of the variability in test results was apparently the improperly calibrated standard solutions. The precision of porphyrin measurements was not influenced by the type of porphyria.
Point-of-Care Testing
Authors: Jansen Rob T. P.
Published: October 2004

In the recent issue of CCLM a paper has been published
on the view of the German Working Group on Point-of-Care Testing (POCT) (1). The issue of POCT is extremely
important and rightly the authors stress the responsibility
of the head of the laboratory.
However, they omit to refer to two important documents
relating to POCT from the European Communities
Confederation of Clinical Chemistry (EC4): one on
the essential criteria for quality systems of medical laboratories
(2) and another on the additional essential criteria
for quality systems of medical laboratories (3), the
latter addressing in particular POCT. Both of these documents
strongly influence new ISO documents on
quality management in medical laboratories. The section
of the German Working Group's paper on organizational
prerequisites for the establishment of POCT in
a hospital could particularly benefit from these references.
The Integration of Multiple Stimulus Features by V1 Neurons
Authors: Grunewald Alexander , Skoumbourdis Evelyn K.
Published: October 2004

We investigated how V1 neurons integrate two stimulus features by presenting stimuli from a stimulus set made up of all combinations of eight different directions of motion and nine binocular disparities. We investigated the occurrence and shape of the resulting joint tuning function. Among V1 neurons, ∼80% were jointly tuned for disparity with orientation or direction. The joint tuning function of all jointly tuned neurons was separable into distinct tuning for disparity on the one hand, and orientation or direction tuning on the other. The degree of separability and the mutual information between the stimulus and the firing rates were strongly correlated. The mutual information of jointly tuned neurons when both features were decoded together was highly correlated with the mutual information when the two features were decoded separately, and the information was then summed. Jointly tuned neurons were just as good at representing information about single features as neurons tuned for only a single feature. The tuning properties of most jointly tuned neurons did not dynamically evolve over time, nor did jointly tuned neurons respond earlier than neurons tuned for only a single feature. The response selectivity of V1 neurons is low and decreases the information that a neuron represents about a stimulus. Together these results suggest that distinct stimulus features are integrated very early in visual processing. Furthermore, V1 generates a distributed representation through low response selectivity that avoids the curse of dimensionality by using separable joint tuning functions.
Olfaction in Olfactory Bulbectomized Rats
Authors: Slotnick Burton , Cockerham Renee , Pickett Erin
Published: October 2004

Experimental rats had their right olfactory bulb removed on postnatal day 2 (P2) and their left olfactory bulb removed on P90. Control rats had one or both olfactory bulbs removed on P90. Before and after their adult-stage surgery, rats were trained using olfactometry and operant conditioning to detect and discriminate odors. Anterograde transport of horseradish peroxidase applied to the olfactory epithelium revealed numerous axons of olfactory sensory neurons in the right hemisphere of 27 experimental rats. These axons terminated in glomerular-like clusters within the frontal neocortex (n= 5) or anterior olfactory nucleus with some axons extending into the subventricular epithelium (n= 22). Seventeen of the experimental rats were able to detect a variety of odors and to discriminate between odors. Performance accuracy was related to the location and density of these anomalous inputs; experimental rats with inputs confined to frontal neocortex and those lacking any inputs to the forebrain were anosmic, as were adult-operated bilaterally bulbectomized rats. Our results provide strong support for the contention that, in the absence of the olfactory bulbs, olfactory connections to novel forebrain sites can support both odor detection and odor discrimination.
Presynaptic Glycine Receptors on GABAergic Terminals Facilitate Discharge of Dopaminergic Neurons in Ventral Tegmental Area
Authors: Ye Jiang-Hong , Wang Fushun , Krnjević Kresimir , Wang Weizhen , Xiong Zhi-Gang , Zhang Jingli
Published: October 2004

GABA-mediated postsynaptic currents (IPSCs) were recorded from dopaminergic (DA) neurons of the ventral tegmental area (VTA) of rats, in acute brain slices, and from enzymatically or mechanically dissociated neurons. In young rats (3-10 d of age), where GABA is excitatory, glycine (1-3 μm) and taurine (10-30 μm) increased the amplitude of evoked IPSCs (eIPSCs) and the frequency of spontaneous IPSCs (sIPSCs) but had minimal postsynaptic effects. Strychnine (1 μm) blocked the action of glycine; when applied alone, it reduced the amplitude of eIPSCs and the frequency of sIPSCs, indicating a tonic facilitation of GABAergic excitation by some endogenous glycine agonist(s). In medium containing no Ca2+, or with Cd2+or tetrodotoxin added, the amplitude and especially the frequency of sIPSCs greatly diminished. In many cells, glycine had no effect on remaining miniature IPSCs, suggesting a preterminal site of glycine receptors (GlyRs). Fura-2 fluorescent imaging showed a glycine-induced increase of [Ca2+] in nerve terminals (on DA neurons), which was suppressed by strychnine or 3 μmω-conotoxin MVIIA. Therefore, the presynaptic GlyR-mediated facilitation of GABAergic transmission seems to be mediated by N- and/or P/Q-type Ca2+channels. In older rats (22-30 d of age), where GABA causes inhibition, the effect of strychnine on GABAergic IPSCs was reversed to facilitation, indicating a tonic glycinergic inhibition of GABA release. Furthermore, glycine (1-3 μm) reduced the amplitude of eIPSCs and the frequency of sIPSCs. Hence, the overall effect of the presynaptic action of glycine is to enhance the firing of DA cells, both in very young and older rats.
Role of Cerebellar Interpositus Nucleus in the Genesis and Control of Reflex and Conditioned Eyelid Responses
Authors: Jiménez-Díaz Lydia , de Dios Navarro-López Juan , Gruart Agnès , Delgado-García José M.
Published: October 2004

The role of cerebellar circuits in the acquisition of new motor abilities is still a matter of intensive debate. To establish the contribution of posterior interpositus nucleus (PIN) to the performance and/or acquisition of reflex and classically conditioned responses (CRs) of the eyelid, the effects of microstimulation and/or pharmacological inhibition by muscimol of the nucleus were investigated in conscious cats. Microstimulation of the PIN in naive animals evoked ramp-like eyelid responses with a wavy appearance, without producing any noticeable plastic functional change in the cerebellar and brainstem circuits involved. Muscimol microinjections decreased the amplitude of reflex eyeblinks evoked by air puffs, both when presented alone or when paired with a tone as conditioned stimulus (CS). In half-conditioned animals, muscimol injections also decreased the amplitude and damped the typical wavy profile of CRs, whereas microstimulation of the same sites increased both parameters. However, neither muscimol injections nor microstimulation modified the expected percentage of CRs, suggesting a major role of the PIN in the performance of eyelid responses rather than in the learning process. Moreover, the simultaneous presentation of CS and microstimulation in well trained animals evoked CRs similar in amplitude to the added value of those evoked by the two stimuli presented separately. In contrast, muscimol-injected animals developed CRs to paired CS and microstimulation presentations, larger than those evoked by the two stimuli when presented alone. It is concluded that the PIN contributes to the enhancement of both reflex and conditioned eyelid responses and to the damping of resonant properties of neuromuscular elements controlling eyelid kinematics.
Fgf8 Regulates the Development of Intra-Neocortical Projections
Authors: Huffman Kelly J. , Garel Sonia , Rubenstein John L. R.
Published: October 2004

The process of generating functionally distinct neocortical areas requires the formation of an intra-neocortical connectivity map. Here, we explore the early development of murine intra-neocortical projections and find that axons from rostral and caudal neurons remain, respectively, within large rostral and caudal domains of the neonatal neocortex. Despite evidence that thalamic input can regulate neocortical areal properties, we found that the neonatal intra-neocortical projection pattern was not perturbed when thalamic input was absent inGbx2mutants. On the contrary, inFgf8hypomorphic mutants, the rostral neocortex of which acquires more caudal molecular properties, caudally located neurons ectopically project axons into the rostral cortex. Therefore, neocortical patterning byFgf8also contributes to arealization through mediating early development of intra-neocortical connectivity.
Spike Timing of Distinct Types of GABAergic Interneuron during Hippocampal Gamma OscillationsIn Vitro
Authors: Hájos Norbert , Pálhalmi János , Mann Edward O. , Németh Beáta , Paulsen Ole , Freund Tamas F.
Published: October 2004

Gamma frequency (30-100 Hz) network oscillations occur in the intact hippocampus during awake, attentive behavior. Here, we explored the underlying cellular mechanisms in anin vitromodel of persistent gamma-frequency oscillations, induced by bath application of 20 μmcarbachol in submerged hippocampal slices at 30 ± 1°C. Current-source density analysis of the field oscillation revealed a prominent alternating sink-source pair in the perisomatic and apical dendritic regions of CA3. To elucidate the active events generating these extracellular dipoles, we examined the firing properties of distinct neuron types. Visually guided unit recordings were obtained from individual CA3 neurons followed by intracellular labeling for anatomical identification. Pyramidal cells fired at 2.82 ± 0.7 Hz, close to the negative peak of the oscillation (0.03 ± 0.65 msec), and often in conjunction with a negative spike-like component of the field potential. In contrast, all phase-coupled interneurons fired after this negative peak. Perisomatic inhibitory interneurons fired at high frequency (18.1 ± 2.7 Hz), shortly after the negative peak (1.97 ± 0.95 msec) and were strongly phase-coupled. Dendritic inhibitory interneurons fired at lower frequency (8.4 ± 2.4 Hz) and with less fidelity and a longer delay after the negative peak (4.3 ± 1.1 msec), whereas interneurons with cell body in the stratum radiatum often showed no phase relationship with the field oscillation. The phase and spike time data of individual neurons, together with the current-source density analysis, support a synaptic feedback model of gamma oscillations primarily involving pyramidal cells and inhibitory cells targeting their perisomatic region.
Phase Sensitivity of Synaptic Modifications in Oscillating Cells of Rat Visual Cortex
Authors: Wespatat Valérie , Tennigkeit Frank , Singer Wolf
Published: October 2004

Synaptic modifications depend on the amplitude and temporal relations of presynaptic and postsynaptic activation. The interactions among these variables are complex and hard to predict when neurons engage in synchronized high-frequency oscillations in the β and γ frequency range, as is often observed during signal processing in the cerebral cortex. Here we investigate in layer II/III pyramidal cells of rat visual cortex slices how synapses change when synchronized, oscillatory multifiber activity impinges on postsynaptic neurons during membrane potential (Vm) oscillations at 20 and 40 Hz. Synapses underwent long-term potentiation (LTP) when EPSPs coincided with the peaks of theVmoscillations but exhibited long-term depression (LTD) when EPSPs coincided with the troughs. The induction of LTP but not of LTD was NMDA receptor dependent, required additional activation of muscarinic receptors in older animals, and persisted in a kainate-driven increased conductance state. Thus, even when neuronal networks engage in high-frequency oscillations, synaptic plasticity remains exquisitely sensitive to the timing of discharges. This is an essential prerequisite for theories which assume that precise synchronization of discharges serves as signature of relatedness in distributed processing.
The Role of the Insular Cortex in Pitch Pattern Perception: The Effect of Linguistic Contexts
Authors: Wong Patrick C. M. , Parsons Lawrence M. , Martinez Michael , Diehl Randy L.
Published: October 2004

Auditory pitch patterns are significant ecological features to which nervous systems have exquisitely adapted. Pitch patterns are found embedded in many contexts, enabling different information-processing goals. Do the psychological functions of pitch patterns determine the neural mechanisms supporting their perception, or do all pitch patterns, regardless of function, engage the same mechanisms? This issue is pursued in the present study by using150-water positron emission tomography to study brain activations when two subject groups discriminate pitch patterns in their respective native languages, one of which is a tonal language and the other of which is not. In a tonal language, pitch patterns signal lexical meaning. Native Mandarin-speaking and English-speaking listeners discriminated pitch patterns embedded in Mandarin and English words and also passively listened to the same stimuli. When Mandarin listeners discriminated pitch embedded in Mandarin lexical tones, the left anterior insular cortex was the most active. When they discriminated pitch patterns embedded in English words, the homologous area in the right hemisphere activated as it did in English-speaking listeners discriminating pitch patterns embedded in either Mandarin or English words. These results support the view that neural responses to physical acoustic stimuli depend on the function of those stimuli and implicate anterior insular cortex in auditory processing, with the left insular cortex especially responsive to linguistic stimuli.
Intrastriatal Transforming Growth Factor α Delivery to a Model of Parkinson's Disease Induces Proliferation and Migration of Endogenous Adult Neural Progenitor Cells without Differentiation into Dopaminergic Neurons
Authors: Cooper Oliver , Isacson Ole
Published: October 2004

We examined the cell proliferative, neurogenic, and behavioral effects of transforming growth factor α (TGFα) in a 6-OHDA Parkinson's disease model when compared with naive rats. Intrastriatal TGFα infusion induced significant proliferation, hyperplastic nodules, and substantial migratory waves of nestin-positive progenitor cells from the adult subventricular zone (SVZ) of dopamine-denervated rats. Interestingly, SVZ cells in naive rats displayed proliferation but minimal migration in response to the TGFα infusion. The cells in the expanded SVZ accumulated cytoplasmic β-catenin, indicating activation of classical Wnt signaling. However, no evidence of any neuronal differentiation was found of these recruited progenitor cells anywhere examined in the brain. Consequently, no evidence of dopaminergic (DA) neurogenesis was found in the striatum or substantia nigra in any experimental group, and amphetamine-induced behavioral rotations did not improve. In summary, the cells in the TGFα-induced migratory cellular wave remain undifferentiated and do not differentiate into midbrain-like DA neurons.