Showing papers in "Biochemia Medica in 2012"

Interrater reliability: the kappa statistic

Abstract: The kappa statistic is frequently used to test interrater reliability. The importance of rater reliability lies in the fact that it represents the extent to which the data collected in the study are correct representations of the variables measured. Measurement of the extent to which data collectors (raters) assign the same score to the same variable is called interrater reliability. While there have been a variety of methods to measure interrater reliability, traditionally it was measured as percent agreement, calculated as the number of agreement scores divided by the total number of scores. In 1960, Jacob Cohen critiqued use of percent agreement due to its inability to account for chance agreement. He introduced the Cohen's kappa, developed to account for the possibility that raters actually guess on at least some variables due to uncertainty. Like most correlation statistics, the kappa can range from -1 to +1. While the kappa is one of the most commonly used statistics to test interrater reliability, it has limitations. Judgments about what level of kappa should be acceptable for health research are questioned. Cohen's suggested interpretation may be too lenient for health related studies because it implies that a score as low as 0.41 might be acceptable. Kappa and percent agreement are compared, and levels for both kappa and percent agreement that should be demanded in healthcare studies are suggested.

Inflammation and haemostasis

Abstract: Inflammation and haemostasis are interrelated pathophysiologic processes that considerably affect each other. In this bidirectional relationship, inflammation leads to activation of the haemostatic system that in turn also considerably influences inflammatory activity. Such, the haemostatic system acts in concert with the inflammatory cascade creating an inflammation-haemostasis cycle in which each activated process promotes the other and the two systems function in a positive feedback loop. The extensive crosstalk between immune and haemostatic systems occurs at level of all components of the haemostatic system including vascular endothelial cells, platelets, plasma coagulation cascade, physiologic anticoagulants and fibrinolytic activity. During inflammatory response, inflammatory mediators, in particular proinflammatory cytokines, play a central role in the effects on haemostatic system by triggering its disturbance in a number of mechanisms including endothelial cell dysfunction, increased platelet reactivity, activation of the plasma coagulation cascade, impaired function of physiologic anticoagulants and suppressed fibrinolytic activity. The two examples of pathophysiologic processes in which the tight interdependent relationship between inflammation and haemostasis considerably contribute to the pathogenesis and/or progression of disease are systemic inflammatory response to infection or sepsis and acute arterial thrombosis as a consequence of ruptured atherosclerotic plaque. Close links between inflammation and haemostasis help explain the prothrombotic tendency in these two clinical conditions in which inflammation shifts the haemostatic activity towards procoagulant state by the ability of proinflammatory mediators to activate coagulation system and to inhibit anticoagulant and fibrinolytic activities. This review summarizes the current knowledge of the complex interactions in the bidirectional relationship between inflammation and haemostasis.

Uric acid as one of the important factors in multifactorial disorders--facts and controversies.

Abstract: With considering serum concentration of the uric acid in humans we are observing hyperuricemia and possible gout development. Many epidemiological studies have shown the relationship between the uric acid and different disorders such are obesity, metabolic syndrome, hypertension and coronary artery disease. Clinicians and investigators recognized serum uric acid concentration as very important diagnostic and prognostic factor of many multifactorial disorders. This review presented few clinical conditions which are not directly related to uric acid, but the concentrations of uric acid might have a great impact in observing, monitoring, prognosis and therapy of such disorders. Uric acid is recognized as a marker of oxidative stress. Production of the uric acid includes enzyme xanthine oxidase which is involved in producing of radical-oxigen species (ROS). As by-products ROS have a significant role in the increased vascular oxidative stress and might be involved in atherogenesis. Uric acid may inhibit endothelial function by inhibition of nitric oxide-function under conditions of oxidative stress. Down regulation of nitric oxide and induction of endothelial dysfunction might also be involved in pathogenesis of hypertension. The most important and well evidenced is possible predictive role of uric acid in predicting short-term outcome (mortality) in acute myocardial infarction (AMI) patients and stroke. Nephrolithiasis of uric acid origin is significantly more common among patients with the metabolic syndrome and obesity. On contrary to this, uric acid also acts is an “antioxidant”, a free radical scavenger and a chelator of transitional metal ions which are converted to poorly reactive forms.

Preanalytical phase--a continuous challenge for laboratory professionals.

Abstract: Preanalytical phase is the most vulnerable part of the total testing process and is considered to be among the greatest challenges to the laboratory professionals. However, preanalytical activities, management of unsuitable specimens and reporting policies are not fully standardized, nor harmonized worldwide. Several standards related to blood sampling and sample transportation and handling are available, but compliance to those guidelines is low, especially outside the laboratory and if blood sampling is done without the direct supervision of the laboratory staff. Furthermore, for some most critical procedures within the preanalytical phase, internationally accepted guidelines and recommendations as well as related quality measures are unfortunately unavailable. There is large heterogeneity in the criteria for sample rejection, the diff erent strategies by which unacceptable samples are managed, processed and test results reported worldwide. Management of unacceptable specimens warrants therefore immediate harmonization. Alongside the challenging and long road of patient safety, preanalytical phase off ers room for improvement, and Editors at Biochemia Medica Journal definitely hope to continue providing a respective mean for reporting studies on diff erent preanalytical phase topics. With pleasure and delight we invite potential future authors to submit their articles examining the quality of various preanalytical activities to Biochemia Medica. We will keep nurturing this topic as our prominent feature and by this we hope to be able to deliver valid evidence for some future guidelines and recommendations.

Impact of the phlebotomy training based on CLSI/NCCLS H03-A6 - procedures for the collection of diagnostic blood specimens by venipuncture

Abstract: Introduction: The activities involving phlebotomy, a critical task for obtaining diagnostic blood samples, are poorly studied as regards the major sources of errors and the procedures related to laboratory quality control. The aim of this study was to verify the compliance with CLSI documents of clinical laboratories from South America and to assess whether teaching phlebotomists to follow the exact procedure for blood collection by venipuncture from CLSI/NCCLS H03-A6 - Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture might improve the quality of the process. Materials and methods: A survey was sent by mail to 3674 laboratories from South America to verify the use of CLSI documents. Thirty skilled phlebotomists were trained with the CLSI H03-A6 document to perform venipuncture procedures for a period of 20 consecutive working days. The overall performances of the phlebotomists were further compared before and after the training program. Results: 2622 from 2781 laboratories that did answer our survey used CLSI documents to standardize their procedures and process. The phlebotomists’ training for 20 days before our evaluation completely eliminated non-conformity procedures for: i) incorrect friction of the forearm, during the cleaning of the venipuncture site to ease vein location; ii) incorrect sequence of vacuum tubes collection; and iii) inadequate mixing of the blood in primary vacuum tubes containing anticoagulants or clot activators. Unfortunately the CLSI H03-A6 document does not caution against both unsuitable tourniquet application time (i.e., for more than one minute) and inappropriate request to clench the fist repeatedly. These inadequate procedures were observed for all phlebotomists. Conclusion: We showed that strict observance of the CLSI H03-A6 document can remarkably improve quality, although the various steps for collecting diagnostic blood specimens are not a gold standard, since they may still permit errors. Tourniquet application time and forearm clench should be verified by all quality laboratory managers in the services. Moreover, the procedure for collecting blood specimens should be revised to eliminate this source of laboratory variability and safeguard the quality.

Iron metabolism: current facts and future directions

Abstract: Iron metabolism has been intensively examined over the last decade and there are many new players in this field which are worth to be introduced. Since its discovery many studies confirmed role of liver hormone hepcidin as key regulator of iron metabolism and pointed out liver as the central organ of system iron homeostasis. Liver cells receive multiple signals related to iron balance and respond by transcriptional regulation of hepcidin expression. This liver hormone is negative regulator of iron metabolism that represses iron efflux from macrophages, hepatocytes and enterocytes by its binding to iron export protein ferroportin. Ferroportin degradation leads to cellular iron retention and decreased iron availability. At level of a cell IRE/IRP (iron responsive elements/iron responsive proteins) system allows tight regulation of iron assimilation that prevents an excess of free intracellular iron which could lead to oxidative stress and damage of DNA, proteins and lipid membranes by ROS (reactive oxygen species). At the same time IRE/IRP system provides sufficient iron in order to meet the metabolic needs. Recently a significant progress in understanding of iron metabolism has been made and new molecular participants have been characterized. Article gives an overview of the current understanding of iron metabolism: absorption, distribution, cellular uptake, release, and storage. We also discuss mechanisms underlying systemic and cellular iron regulation with emphasis on central regulatory hormone hepcidin.

Stability studies of common biochemical analytes in serum separator tubes with or without gel barrier subjected to various storage conditions

Abstract: Introduction: The collected and shipped blood samples are exposed to a various extra-analytical factors prior to analysis. The aim of the study was to determine the stability of analytes in serum gel tubes and plain tubes exposed to a range of storage temperatures and times after centrifugation. Materials and methods: Fifteen healthy volunteers were recruited and venous blood was collected into four tubes, two with and two without gel separator. Analyzing the baseline samples in 30 min, all were stored at 4oC or 24oC for 6, 12, 18, 24, 30, 36, 48 and 72 hours and 1 week. Sixteen biochemical anaytes were measured on each sample. Variations remained under the desirable bias considered as clinically insignifi cant. Results: On day three, most analytes remained stable including albumin, protein, creatinine, cholesterol, triglycerides, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminotransferase (ALT), creatine kinase (CK), lactate dehydrogenase (LD) regardless of tube types. Glucose concentration decreased markedly (P = 0.001) beginning from the fi rst hours of storage in plain serum. The stability ma ximized for the analytes including glucose, total bilirubin, urea nitrogen (BUN), uric acid stored at 4 oC in gel tubes. Aspartate aminotransferase (AST) activity increased signifi cantly (P = 0.002) up to 48-h, however bias was no t signifi cant clinically. High density lipoprotein (HDL) concentr ation was stable in gel tubes at 24 oC, in plain tubes at 4 oC stored up to 36-h. Conclusion: Serum gel or non-gel tubes might be used interchangeably for 11 analytes chilled or at 24 oC, whereas some restrictions must be applied for glucose, AST, BUN, HDL, and uric acid.

Free DNA--new potential analyte in clinical laboratory diagnostics?

Abstract: The existence of cell free DNA in the human circulatory system has been known since the 1950s, however, intensive research in this area has been conducted for the last ten years. This review paper brings a short overview of the existing literature concerning the cell free DNA research in various clinical fields and pathological states and considers the application possibilities of this new analyte in clinical laboratory diagnostics. At the moment, cell free DNA is most widely used for the purpose of non-invasive prenatal diagnosis of fetal sex or fetal RhD status. The recent discovery of epigenetic changes in placental/fetal DNA and the detection of fetal/placental-specific RNAs have made it possible to use this technology in all pregnancies irrespective of the gender of the fetus. With the application of new techniques such as next generation sequencing, digital PCR and mass spectrometry, it is now possible to detect very small amounts of specific DNA in the presence of excess of other nonspecific nucleic acids. Second most probable application is in oncology, where detection and monitoring of tumors is now possible by the detection of tumor-derived nucleic acids. Third promising field for near future implementation of this analyte is transplantation medicine, where free DNA level could serve as a marker of transplant rejection. Before any further utilization of this new biomarker, pre-analytical and analytical aspects of free DNA analysis remain to be standardized. In the field of noninvasive prenatal diagnosis, important ethical, legal and social questions remain to be discussed.

The new oral anticoagulants and the future of haemostasis laboratory testing

Abstract: The tests currently employed within most haemostasis laboratories to monitor anticoagulant therapy largely comprise the prothrombin time (PT)/ International Normalised Ratio (INR) and the activated partial thromboplastin time (APTT). These are respectively used to monitor Vitamin K antagonists (VKAs) such as warfarin, and unfractionated heparin. Additional tests that laboratories may also employ for assessing or monitoring unfractionated heparin include thrombin time (TT) and the anti-Xa assay, which can also be used to monitor low molecular weight heparin. Several new anti-thrombotic agents have recently emerged, or are in the final process of clinical evaluation. These novel drugs that include Dabigatran etexilate and Rivaroxaban would not theoretically require monitoring; however, testing is useful in specific situations. The tests currently used to monitor VKAs and heparin are typically either too sensitive or too insensitive to the new drugs to be used as ‘typically performed in laboratories’, and may thus require some methodological adjustments to increase or decrease their sensitivity. Alternately, different tests may be better employed in these assessments. Whatever the case, laboratories may soon be performing a reduced or possibly increased number of tests, the same kind of tests but perhaps differently, or conceivably different assay panels. Specific laboratory guidance on the choice of the appropriate test to be ordered according to the drug being administered, as well as on appropriate interpretation of test results, will also be necessary. The current report reviews the current state of play and provides a glimpse to the possible future of the coagulation laboratory.

Practical recommendations for statistical analysis and data presentation in Biochemia Medica journal

Abstract: The aim of this article is to highlight practical recommendations based on our experience as reviewers and journal editors and refer to some most common mistakes in manuscripts submitted to Biochemia Medica. One of the most important parts of the article is the Abstract. Authors quite often forget that Abstract is sometimes the first (and only) part of the article read by the readers. The article Abstract must therefore be comprehensive and provide key results of your work. Problematic part of the article, also often neglected by authors is the subheading Statistical analysis, within Materials and methods, where authors must explain which statistical tests were used in their data analysis and the rationale for using those tests. They also need to make sure that all tests used are listed under Statistical analysis section, as well as that all tests listed are indeed used in the study. When writing Results section there are several key points to keep in mind, such as: are results presented with adequate precision and accurately; is descriptive analysis appropriate; is the measure of confidence provided for all estimates; if necessary and applicable, are correct statistical tests used for analysis; is P value provided for all tests, etc. Especially important is not to make any conclusions on the causal relationship unless the study is an experiment or clinical trial. We believe that the use of the proposed checklist might increase the quality of the submitted work and speed up the peer-review and publication process for published articles.

Insights into complexity of Congenital disorders of glycosylation

Abstract: Biochemical and biological properties of glycoconjugates are strongly determined by the specific structure of its glycan parts. Glycosylation, the covalent attachment of sugars to proteins and lipids, is very complex and highly-coordinated process involving > 250 gene products. Deficiency of glycosylation enzymes or transporters results in impaired glycosylation, and consequently pathological modulation of many physiological processes. Inborn defects of glycosylation enzymes, caused by the specific mutations, lead to the development of rare, but severe diseases – congenital disorders of glycosylation (CDGs). Up today, there are more than 45 known CDGs. Their clinical manifestations range from very mild to extremely severe (even lethal) and unfortunately, only three of them can be eff ectively treated nowadays. CDG symptoms highly vary, though some are common for several CDG types but also for other unrelated diseases, especially neurological ones, leaving the possibility that many CDGs cases are under- or mis-diagnosed. Glycan analysis of serum transferrin (by isoelectric focusing or more sophisticated methods, such as HPLC (high-performance liquid chromatography) or MALDI (matrix-assisted laser desorption/ionization)) or serum N-glycans (by MS), enzyme activity assays and DNA sequence analysis are the most frequently used methods for CDG screening and identification, since no specific tests are available yet. In this review we summarize the current knowledge on the clinical, biochemical and genetic characteristic of distinct CDGs, as well as existing diagnostic and therapeutic procedures, aiming to contribute to the awareness on the existence of these rare diseases and encourage the eff orts to elucidate its genetic background, improve diagnostics and develop new strategies for their treatment.

The role of CRP and inflammation in the pathogenesis of age-related macular degeneration

Abstract: Age-related macular degeneration (AMD) is a complex, degenerative and progressive disease involving the multiple genetic and environmental factors that can result in severe visual loss. The etiology of AMD is not well understood. Many theories exist and feature mechanisms of oxidative stress, atherosclerotic-like changes, genetic predisposition and inflammation. The most recent clinical studies appointed to a great role of inflammation and C-reactive protein (CRP) in the pathogenesis of AMD. There is a large body of evidence indicating the association of CRP with endothelial dysfunction, oxidative stress and production of reactive oxygen species (ROS), as well as with lipid status disorder in AMD patients. According to recent studies, CRP is definitely not only the inflammatory marker but also a mediator of development of the vascular disorders in the retinal circulation. The results obtained from the present studies may help our understanding the pathogenesis of the retinal vascular disease associated with high levels of CRP.

Biomedical research platforms and their influence on article submissions and journal rankings: An update

Abstract: After being indexed in 2006 in EMBASE/Excerpta Medica and Scopus, and later in Science Citation Index Expanded and Journal Citation Reports/ Science Edition citation databases, Biochemia Medica launched a new web page and online manuscript submission system in 2010, and celebrated its fiImpact Factor in the same year. Now, starting from the end of the 2011, the journal will also be indexed in PubMed/Me dline, and this will contribute to increase the journal’s exposure and accessibility worldwide. This is an important breakthrough, which is expected to further increase the popularity of the journal, as well as the submission rate and citations. Although several tools are currently available as Web resources to retrieve scientifi c articles, whose functioning and basic criteria are thou ght to be rather similar, the functionality, coverage, notoriety and prominence may diff er widely. The recent indexing of Biochemia Medica in PubMed/Medline has thereby given us the opportunity to provide a timely update on biomedical research platforms, their relationship with article submissions and journal rankings.

Preanalytical management: serum vacuum tubes validation for routine clinical chemistry.

Abstract: Introduction: The validation process is essential in accredited clinical laboratories. Aim of this study was to validate fi kinds of serum vacuum tubes for routine clinical chemistry laboratory testing. Materials and methods: Blood specimens from 100 volunteers in fi ve diff erent serum vacuum tubes (Tube I: VACUETTE®, Tube II: LABOR IMPORT®, Tube III: S-Monovette®, Tube IV: SST® and Tube V: SST II®) were collected by a single, expert phlebotomist. The routine clinical chemistry tests were analyzed on cobas® 6000 module. The signifi cance of the diff erences between samples was as sessed by paired Student’s t-test after checking for normality. The level of statistical signifi cance was set at P < 0.005. Finally, the biases from Tube I, Tube II, Tube III, Tube IV and Tube V were compared with the current desirable quality specifi cati ons for bias (B), derived from biological variation. Results and conclusions: Basically, our validation will permit the laboratory or hospital managers to select the brand’s vacuum tubes validated according him/her technical or economical reasons, in order to perform the following laboratory tests: glucose, total cholesterol, high density lipoprotein-cholesterol, triglycerides, total protein, albumin, blood urea nitrogen, uric acid, alkaline phosphatise, aspartate aminotransferase, gammaglutamyltransferase, lactate dehydrogenase, creatine kinase, total bilirubin, direct bilirubin, calcium, iron, sodium and potassium. On the contrary special attention will be required if the laboratory already performs creatinine, amylase, phosphate and magnesium determinations and the quality laboratory manager intend to change the serum tubes. We suggest that laboratory management should both standardize the procedures and frequently evaluate the quality of in vitro diagnostic devices.

Macroprolactinemia: new insights in hyperprolactinemia.

Abstract: Hypersecretion of prolactin by lactotroph cells of the anterior pituitary may lead to hyperprolactinemia in physiological, pathological and idiopathic conditions. Most patients with idiopathic hyperprolactinemia may have radiologically undetected microprolactinomas, but some may present other causes of hyperprolactinemia described as macroprolactinemia. This condition corresponds to the predominance of higher molecular mass prolactin forms (big-big prolactin, MW > 150 kDa), that have been postulated to represent prolactin monomer complexed with anti-prolactin immunoglobulins or autoantibodies. The prevalence of macroprolactinemia in hyperprolactinemic populations between 15-46% has been reported. In the pathophysiology of macroprolactinemia it seems that pituitary prolactin has antigenicity, leading to the production of anti-prolactin autoantibodies, and these antibodies reduce prolactin bioactivity and delay prolactin clearance. Antibody-bound prolactin is big enough to be confined to vascular spaces, and therefore macroprolactinemia develops due to the delayed clearance of prolactin rather than increased production. Although the clinical symptoms are less frequent in macroprolactinemic patients, they could not be differentiated from true hyperprolactinemic patients, on the basis of clinical features alone. Although gel filtration chromatography (GFC) is known to be the gold standard for detecting macroprolactin, the polyethylene glycol precipitation (PEG) method has offered a simple, cheap, and highly suitable alternative. In conclusion, macroprolactinemia can be considered a benign condition with low incidence of clinical symptoms and therefore hormonal and imaging investigations as well as medical or surgical treatment and prolonged follow-up are not necessary.

Relationship between serum interleukin-1beta levels and acute phase response proteins in patients with familial Mediterranean fever.

Abstract: Introduction The aim of this study was to investigate whether serum levels of interleukin-1beta (IL-1beta) has any possible correlation on inflammatory parameters such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and fibrinogen concentration in patients with familial Mediterranean fever (FMF) patients during attack-free period. Materials and methods The serum levels of IL-1beta, as an indicator of cytokines status, and the acute phase response proteins, CRP, ESR and fibrinogen levels were evaluated in 35 attack-free patients with FMF and 25 healthy volunteers. Results Serum IL-1beta levels were significantly higher in patients with FMF than control subjects (P = 0.018). There was no statistically significant difference in the serum levels of ESR, CRP and fibrinogen between two groups (P = 0.181, P = 0.816, P = 0.686, respectively). There was a significant correlation between IL-1beta and CRP (r = 0.513, P = 0.002) values of FMF group. Conclusions In conclusion, our results confirm the presence of increased IL-1beta levels in FMF patients during attack-free period. Serum IL-1beta values seems to correlate with CRP levels. The elevation of IL-1beta levels may be important in monitoring subclinical inflammation of attack free period in FMF patients.

The effects of different syringe volume, needle size and sample volume on blood gas analysis in syringes washed with heparin

Abstract: Introduction: We evaluated the eff ect of diff erent syringe volume, needle size and sample volume on blood gas analysis in syringes washed w ith heparin. Materials and methods: In this multi-step experimental study, percent dilution ratios (PDRs) and fiheparin concentrations (FHCs) were calcu- lated by gravimetric method for determining the eff ect of syringe volume (1, 2, 5 and 10 mL), needle size (20, 21, 22, 25 and 2 6 G) and sample volu- me (0.5, 1, 2, 5 and 10 mL). The eff ect of diff erent PDRs and FHCs on blood gas and electrolyte parameters were determined. The erroneous results from nonstandardized sampling were evaluated according to RiliBAK's TEa. Results: The increase of PDRs and FHCs was associated with the decrease of syringe volume, the increase of needle size and the decrease of sample volume: from 2.0% and 100 IU/mL in 10 mL-syringe to 7.0% and 351 IU/mL in 1 mL-syringe; from 4.9% and 245 IU/mL in 26G to 7.6% and 380 IU/mL in 20 G with combined 1 mL syringe; from 2.0% and 100 IU/mL in full-fi lled sample to 34% and 1675 IU/mL in 0.5 mL suctioned sam ple into 10 mL- syringe. There was no statistical diff erence in pH; but the percent decreasing in pCO 2 , K + , iCa 2+ , iMg 2+ ; the percent increasing in pO 2 and Na + were statistical signifi cance compared to samples full-fi lled in syringes. The all changes in pH and pO 2 were acceptable; but the changes in pCO 2 , Na + , K + and iCa 2+ were unacceptable according to TEa limits except fullfi lled-syringes. Conclusions: The changes in PDRs and FHCs due nonstandardized sampling in syringe washed with liquid heparin give rise to erroneous test results for pCO 2 and electrolytes.

Diagnostic accuracy of heart fatty acid binding protein (H-FABP) and glycogen phosphorylase isoenzyme BB (GPBB) in diagnosis of acute myocardial infarction in patients with acute coronary syndrome.

Abstract: Introduction: This study aimed to assess whether heart fatty acid-binding protein (H-FABP) and glycogen phosphorylase isoenzyme BB (GPBB) could be used for the accurate diagnosis of acute myocardial infarction (AMI) in acute coronary syndrome (ACS) patients. Materials and methods: The study included 108 ACS patients admitted to a coronary unit within 3 h after chest pain onset. AMI was distinguished from unstable angina (UA) using a classical cardiac troponin I (cTnI) assay. H-FABP and GPBB were measured by ELISA on admission (0 h) and at 3, 6, 12, and 24 h after admission; their accuracy to diagnose AMI was assessed using statistical methods. Results: From 92 patients with ACS; 71 had AMI. H-FABP and GPBB had higher peak value after 3 h from admission than cTnI (P = 0.001). Both markers normalized at 24 h. The area under the receiver operating characteristic curves was significantly greater for both markers in AMI patients than in UA patients at all time points tested, including admission (P < 0.001). At admission, the H-FABP (37%) and GPBB (40%) sensitivities were relatively low. They increased at 3 and 6 h after admission for both markers and decreased again after 24 h. It was 40% for H-FABP and approximately 2-times lower for GPBB (P < 0.01). In AMI patients, both biomarkers had similar specificities, positive- and negative-predictive values, positive and negative likelihood ratios, and risk ratios for AIM. Conclusion: H-FABP and GPBB can contribute to early AMI diagnosis and can distinguish AMI from UA.

Nonalcoholic fatty liver disease associated with impairment of kidney function in nondiabetes population.

Abstract: BACKGROUND Nonalcoholic fatty liver disease (NAFLD) is associated with the increased burden of kidney. However, there is still no large population study to explore the potential relationship between NAFLD and mild kidney function damage (MKFD) after adjusted for confounding factors. This study is to test the hypothesis that NAFLD is associated with MKFD under controlling the effects of confounding factors. MATERIALS AND METHODS Levels of serum fasting glucose, creatinine, cholesterol, triglyceride, alanine aminotransferase and aspartate aminotransferase were analyzed from 1412 Chinese Han adults. Questionnaire and physical examination were performed to explore the potential association of NAFLD with kidney function. RESULTS NAFLD was associated with impairment of kidney function. Multivariate-adjusted odds ratio illustrated that, compared to subjects with normal liver, NAFLD subjects had a significantly higher risk of MKFD with or without adjusted for blood glucose and other covariates (P = 0.041). Further results from multi-interaction analysis demonstrated that the underlying mechanisms linked NAFLD with impaired kidney function may be that they share common risk factors and similar pathological processes. CONCLUSIONS The most striking finding of this study is that NAFLD is negatively associated with kidney function, in nondiabetic population. NAFLD and MKFD may share similar risk factors and/or pathological processes.

Reproducibility, accuracy and concordance of Accutrend® Plus for measuring circulating lipid concentration in adults

Abstract: Introduction: The determination of lipid biomarkers by capillary sampling may be useful in the screening, diagnosis and/or personal management of hyperlipidemia and cardiovascular risk. It remains unclear whether the use of the Accutrend® Plus system is appropriate. This study aimed to assess its reproducibility, accuracy and concordance for blood lipid profi ling in adults. Materials and methods: Fasting capillary total cholesterol (TC) and triglyceride (TG) concentration on Accutrend® Plus were compared with their venous analogues obtained by a laboratory reference method in sixty-one adults (27 men and 34 women, aged 33.0 years). Supplementary capillary sampling was performed at two consecutive days taking into account macro-nutrient intake. Results: The day-to-day reproducibility of the Accutrend® Plus system proved to be high for TC (ICC = 0.85, P < 0.001), but moderate for TG (ICC = 0.68, P < 0.001). Strong correlations (r ≥ 0.80, P < 0.001) with the reference method were found for TC and TG. Mean diff erence (limits of agreement) were: 0.26 mmol/L (-0.95, 1.47) for TC, and -0.16 mmol/L (-1.29, 0.98) for TG. The concordance for subject classifi cation according to the National Cholesterol Education Program (NCEP) guidelines was signifi cant (P < 0.001), with substantial agreement for TC (κ w = 0.67), and moderate agreement for TG (κ w = 0.50). Conclusions: Day-to-day reproducibility of the Accutrend® Plus device for TC and TG is not optimal and lacks accuracy when compared to the reference laboratory method. The concordance between both methods for classifying subjects according to the NCEP is inadequate. Accutrend® Plus device should not be interchangeably used as a substitution for the standard laboratory methods in the diagnosis of hyperlipidemia.

Cardiac indexes, cardiac damage biomarkers and energy expenditure in professional cyclists during the Giro d'Italia 3-weeks stage race.

Abstract: Introduction: The study of cardiac response to strenuous and continuous exercise is crucial to understanding the physiology of endurance. N-terminal proB-type natriuretic peptide (NT-proBNP) is a potential marker for monitoring myocardial wall stress, and troponins (TnT and TnI) are widely used in the diagnosis of cardiac ischemia and infarction. Strenuous exercise may generate transitory ischemia, myocardial stress, and diastolic left ventricular dysfunction, inducing the increased production of both these biomarkers. We measured changes in NT-proBNP and TnT in elite cyclists during a 3-week stage race, a model of strenuous exercise. Materials and methods: The study population was 9 professional cyclists participating in the 2011 Giro d’Italia. Pre-analytical and analytical phases scrupulously followed offi cial recommendations. Anthropometric data, net energy expenditure and cardiac indexes (rate, diastolic and systolic blood pressure) were recorded. Blood samples were drawn pre-race (day -1) and at days 12 and 22; NT-proBNP and highly sensitive-troponin (HsTnT) concentrations were assayed and corrected for plasma volume changes. Results: Body-mass index decreased and energy expenditure increased by 52% during the race. NT-proBNP concentrations increased [day -1: 23.52 ng/L (9.67-34.33); day 12: 63.46 ng/L (22.15-93.31); P = 0.039; day 22: 89.26 ng/L (34.66-129.78) vs. day -1; P < 0.001] and correlated with heart rate (r = -0.51; P = 0.006), systolic pressure (r = 0.39; P = 0.046) and energy expenditure (r = 0.70; P < 0.001). TnT concentrations did not vary, but a widened TnT amplitude distribution was observed. Conclusions: Increases in NT-proBNP correlated with higher energy expenditure over a 3-week cycling stage race, possibly indicating myocardial stress.

Investigation of unusual high serum indices for lipemia in clear serum samples on siemens analysers dimension.

Abstract: Introduction: We present our work of monitoring 202 different patients with markedly elevated serum index for lipemia whereby serum samples were clear. We tried to clarify the cause of occurrence of these indices which were detected in the years 2006-2010 on Siemens Dimension analyzers. Materials and methods: In samples with unusual lipemia index we measured the concentration of lipids (total cholesterol, triglycerides, HDL and LDL cholesterol, Lp(a), ApoA1, ApoB), total proteins and checked for possible interferents (rheumatoid factor, immunoglobulins). We performed serum protein and immuno- electrophoresis. We investigated the repeatability of unusual lipemia indices during the day and after different time periods and we compared them on four different analyzers (RXL Max, Vista, Hitachi 911 and former Olympus AU640). Results: In 87% of 202 samples we found a monoclonal or biclonal peak in serum protein electrophoresis. Different types of paraproteins were confirmed with immunofixation electrophoresis. In the remaining 13%, polyclonal elevated concentrations of immunoglobulins were measured. Other parameters had no influence on appearing of these indices. The repeatability of indices was good during the first day of measurements (P va lues > 0.05) and markedly lower in the next days or after 3 and 12 months (P values < 0.05). The indices were elevated only on Dimension analyzers, but not on Hitachi and former Olympus analysers. Conclusion: A markedly elevated lipemia index in a clear serum sample measured on Siemens analyzers Dimension indicates a high possibility for the presence of a paraprotein in the sample.

Analysis of censored data

Abstract: Analyzing events over time is often complicated by incomplete, or censored, observations. Special non-parametric statistical methods were developed to overcome difficulties in summarizing and comparing censored data. Life-table (actuarial) method and Kaplan-Meier method are described with an explanation of survival curves. For the didactic purpose authors prepared a workbook based on most widely used Kaplan-Meier method. It should help the reader understand how Kaplan-Meier method is conceptualized and how it can be used to obtain statistics and survival curves needed to completely describe a sample of patients. Log-rank test and hazard ratio are also discussed.

Inherited prothrombotic risk factors in children with first ischemic stroke

Abstract: Stroke in children is a heterogeneous disorder. Over 100 risk factors for stroke have been reported and genetic predisposition to stroke has been established. The most frequently reported risk factors are congenital heart malformations, hemolytic anemias, collagen vascular diseases, some rare inborn metabolic disorders, trauma, infection and thrombophilia. The aim of this article is to provide an overview of investigated inherited prothrombotic risk factors in children with first ischemic stroke. Various prothrombotic risk factors have been investigated in pediatric stroke including elevated homocysteine and lipoprotein (a), antithrombin, protein C and protein S deficiency, Factor V Leiden, Factor II G20210A and plasminogen activator inhibitor-1 4G/5G polymorphism. Despite similar criteria for inclusion of different studies in meta-analyses investigating first ischemic stroke in children, the obtained results were not consistent for all prothrombotic risk factors. The discrepancies found could be explained by methodological issues like different sample sizes, patient populations included and lack of controls. In order to provide the necessary power for randomized control trials, multi-center, multi-national approaches like International Pediatric Stroke Study have been initiated with the aim to describe risk factors for childhood stroke and explore their relationship with presentation, age, geography, and infarct characteristics. Although it is evident from numerous studies that the frequency of inherited prothrombotic factors is increased in pediatric stroke, single thrombophilia does not fully explain stroke in a child as it represents only a mild risk factor. Further studies are needed, as improved understanding of underlying mechanisms will improve primary and secondary prevention of childhood stroke.

Bowels control brain: gut hormones and obesity

Abstract: Peptide hormones are released from the gastrointestinal tract in response to nutrients and communicate information regarding the current state of energy balance to the brain. These hormones regulate appetite, energy expenditure and glucose homeostasis. They can act either via the circulation at target peripheral tissues, by activation of the vagus nerve or by acting on key brain regions implicated in energy homeostasis such as the hypothalamus and brainstem. This review gives an overview of the main gut hormones implicated in the regulation of food intake and how some of these are being targeted to develop anti obesity treatments.

Association between 11β-hydroxysteroid dehydrogenase type 1 gene polymorphisms and metabolic syndrome

Abstract: INTRODUCTION: The enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) catalyzes the conversion of the hormonally inactive cortisone to active cortisol, thus facilitating glucocorticoid receptor activation in target tissues. Increased expression of 11beta-HSD1 in adipose tissue has been associated with obesity and insulin resistance. In this study, we investigated the association of two 11beta-HSD1 gene (HSD11B1) polymorphisms with the metabolic syndrome (MetS) and its characteristics in the Bosnian population. MATERIALS AND METHODS: The study included 86 participants: 43 patients diagnosed with MetS and 43 healthy controls. Subjects were genotyped for two HSD11B1 gene polymorphisms: rs846910: G > A and rs45487298: insA, by the high resolution melting curve analysis. Genotype distribution and an influence of genotypes on clinical and biochemical parameters were assessed. RESULTS: There was no significant difference in the mutated allele frequencies for the two HSD11B1 gene polymorphisms between MetS patients and controls. In MetS patients, no significant associations between disease-associated traits and rs45487298: insA were found. Regarding rs846910: G > Avariant, heterozygous patients (G/A) had significantly lower systolic (P = 0.017) and diastolic blood pressure (P = 0.015), lower HOMA-IR index (P = 0.011) and higher LDL-cholesterol levels (P = 0.049), compared to the wild-type homozygotes. In the control group, rs45487298: insA polymorphism was associated with lower fasting plasma insulin levels (P = 0.041), lower homeostasis model assessment insulin resistance (HOMA-IR) index (P = 0.041) and lower diastolic blood pressure (P = 0.048). Significant differences between rs846910: G > A genotypes in controls were not detected. Haplotype analysis confirmed the association of rs45487298: insA with markers of insulin resistance in the control subjects. CONCLUSIONS: Our results indicate that a common rs45487298: insA polymorphism in HSD1181 gene may have a protective effect against insulin resistance.

The most common nonconformities encountered during the assessments of medical laboratories in Hong Kong using ISO 15189 as accreditation criteria.

Abstract: Introduction ISO 15189 was a new standard published in 2003 for accrediting medical laboratories. We believe that some requirements of the ISO 15189 standard are especially difficult to meet for majority of laboratories. The aim of this article was to present the frequency of nonconformities to requirements of the ISO 15189 accreditation standard, encountered during the assessments of medical laboratories in Hong Kong, during 2004 to 2009. Materials and methods Nonconformities reported in assessments based on ISO 15189 were analyzed in two periods - from 2004 to 2006 and in 2009. They are categorized according to the ISO 15189 clause numbers. The performance of 27 laboratories initially assessed between 2004 and 2006 was compared to their performance in the second reassessment in 2009. Results For management requirements, nonconformities were most frequently reported against quality management system, quality and technical records and document control; whereas for technical requirements, they were reported against examination procedures, equipment, and assuring quality of examination procedures. There was no major difference in types of common nonconformities reported in the two study periods. The total number of nonconformities reported in the second reassessment of 27 laboratories in 2009 was almost halved compared to their initial assessments. The number of significant nonconformities per laboratory significantly decreased (P = 0.023). Conclusion Similar nonconformities were reported in the two study periods though the frequency encountered decreased. The significant decrease in number of significant nonconformities encountered in the same group of laboratories in the two periods substantiated that 15015189 contributed to quality improvement of accredited laboratories.

Investigation of ABCA1 C69T polymorphism in patients with type 2 diabetes mellitus.

Abstract: Introduction: Non insulin dependent diabetes mellitus is the most common type of diabetes. Genetic factors, lipid profi les, hypertension ar e potential risk factors for diabetes mellitus. Adenosine binding cassette transporter proteins 1 (ABCA1) plays a role in cholesterol metabolism, especially high density lipoprotein (HDL-cholesterol). There are multiple mechanisms by which HDL-cholesterol can be atheroprotective, it is clear that the relative activity of ABCA1 plays a major role. We aimed to investigate association of ABCA1 C69T gene polymorphism with lipid levels in Turkish type 2 diabetic patients. Materials and methods: After isolation of DNA by ethanol precipitation we determined ABCA1 gene polymorphism by using polimerase chain reaction - restriction fragment lenght polymorphism (PCR-RFLP) method in 107 type 2 diabetic patients and 50 healthy controls. Results: We have observed that the frequency of TT genotype is signifi cantly higher in healthy controls compared to patients (14% vs. 3%; P = 0.008). Also frequency of T allele was higher in controls than in patients (34% vs. 21%; P = 0.020; OR (95% CI) = 0.52 (0.30-0.88)). There was no association of lipid levels and ABCA1 C69T polymorphism subgroups. Conclusion: We have found signifi cantly higher frequency of both T allele and genotype in control group when compared to patients that made us think that T allele may be a protective factor against diabetes mellitus. But, we could not fia relationship between genotyp es and lipid concentrations in our two groups. Larger studies will help us to understand the relationship between ABCA1 C69T genotype and lipid parameters in diabetes mellitus.

FABP 2 gene polymorphism and metabolic syndrome in elderly people of Croatian descent

Abstract: Introduction: Metabolic syndrome (MetS) is a multifactorial disorder in which dyslipidemia plays an important role. Fatty acid-binding protein 2 (FABP 2) is responsible for transport of free fatty acids in the intestinal endothelium cells. FABP2-genetic variants might aff ect plasma lipid concentrations and intracellular lipid transport. The aim of this study was to investigate the association between FABP2 Ala54Thr genetic polymorphism and metabolic syndrome and some biochemical and anthropological parameters in elderly subjects. Materials and methods: This cross-sectional study included 140 men and 176 women older than 70 years. Fasting serum concentration of glucose, lipid parameters, total proteins and C-reactive protein were determined by standardized methods. Presence (MetS(+)) or absence (MetS(-)) of MetS was determined according to criteria of the International Diabetes Federation. FABP2 genetic polymorphism Ala54Thr (rs1799883) was genotyped with PCR-RFPL. Results: The genotype frequencies for Ala/Ala, Ala/Thr and Thr/Thr genotype were 60, 36 and 6 in MetS(-), and 131, 70 and 13 in MetS(+), respectively, without statistical signifi cance (P = 0.567). Ala/Ala genotype was a subgroup of non-carriers, while Ala/Thr and Thr/Th r genotypes were Thr54-carriers. Median triglyceride concentration was signifi cantly lower in carriers then in non-carriers for whole MetS(+) gr oup (P = 0.050); there were no signifi cant diff erence between men with MetS (P = 0.144), but there was a diff erence between women with MetS (P = 0. 020). T-test showed that mean HDL cholesterol concentrations in MetS(+) group for Thr54-carriers was signifi cantly higher in whole group (P = 0.001), and for both genders (men P = 0.039; women P = 0.004) as compared to non-carriers. Conclusions: FABP2 genetic polymorphism is associated with lower triglyceride and higher HDL-cholesterol concentrations in elderly subjects with MetS. This genetic variation might be a useful marker for understanding dyslipidemia in MetS.

Our profession now has a European name: specialist in laboratory medicine.

Abstract: We need a common name to have a clear identity which best describes the scope of the work we carry out for the patients. A clear and easily understood name which reflects the level of education and training of a specialist in the medical laboratory, and hence eligibility to be on the EC4 Register, is therefore needed, whatever academic background and whether polyvalent or sub-specialised.