Volume 49, Issue 4

The aim of this article is to review the diagnostic and prognostic relevance of measurement of brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in pediatric patients with congenital cardiac diseases (CHD). A computerized literature search in the National Library of Medicine using the keywords “BNP assay” and “NT-proBNP assay”+neonate/s and newborn/s was performed. Next, we refined the analysis to include only the studies specifically designed to evaluate the clinical usefulness of BNP and NT-proBNP measurements in children with CHD. Several authors suggested that BNP/NT-proBNP is clinically helpful as a diagnostic and prognostic marker for children with suspected CHD. BNP values are age dependent, even in paediatric populations. Unfortunately, accurate reference values for BNP and NT-proBNP for neonatal ages have only recently become available. As a result, the lack of homogenous and accurate decisional levels in the neonatal period greatly limits the clinical impact of the BNP assay, and also contributed to the production of conflicting results. Regardless of age, there is great variability in BNP/NT-proBNP values among CHD characterized by different hemodynamic and clinical conditions. In particular, cardiac defects characterized by left ventricular volume and pressure overload usually show a higher BNP response than CHD which is characterized by right ventricular volume or pressure overload. BNP and NT-proBNP may be considered helpful markers in the integral clinical approach for patients with CHD. Measurement of BNP cannot replace cardiac imaging (including echocardiography, angiography and magnetic resonance), but provide independent, low cost and complementary information for the evaluation of cardiac function and clinical status.

Clinical laboratories provide an invaluable service to millions of people around the world in the form of quality diagnostic care. Within the clinical laboratory industry the impetus for change has come from technological development (miniaturization, nanotechnology, and their collective effect on point-of-care testing; POCT) and the increasingly global nature of laboratory services. Potential technological gains in POCT include: the development of bio-sensors, microarrays, genetics and proteomics testing, and enhanced web connectivity. In globalization, prospective opportunities lie in: medical tourism, the migration of healthcare workers, cross-border delivery of testing, and the establishment of accredited laboratories in previously unexplored markets. Accompanying these impressive opportunities are equally imposing challenges. Difficulty transitioning from research to clinical use, poor infrastructure in developing countries, cultural differences and national barriers to global trade are only a few examples. Dealing with the issues presented by globalization and the impact of developing technology on POCT, and on the clinical laboratory services industry in general, will be a daunting task. Despite such concerns, with appropriate countermeasures it will be possible to address the challenges posed. Future laboratory success will be largely dependent on one’s ability to adapt in this perpetually shifting landscape.

The major characteristic of asthma is persistent airway inflammation that fails to resolve spontaneously. Dysregulation of pro- and anti-inflammatory mechanisms is responsible for the development of chronic inflammation. The inflammatory reaction is mediated by numerous cells and their mediators. Detection and quantification of airway inflammation in children are subject to many requirements, e.g., use of biologic samples obtained in a non-invasive way; use of standardized analytical methods to determine biomarkers that can identify inflammation processes (inflammation itself, oxidative stress, apoptosis and remodelling); determining the role of systemic inflammation; assessment of correlation of various biomarkers of inflammation with clinical parameters and their diagnostic efficacy; providing a tool(s) to monitor diseases, and to evaluate adequacy of therapy; and predicting the clinical course of inflammation and prognosis of asthma. Using standardized analyses, it is now possible to determine direct markers of local inflammation, i.e., fractional nitric oxide (marker of oxidative stress) in exhaled breath, pH (marker of acid stress) in breath condensate, and indirect markers in blood/serum, i.e., eosinophil granulocytes (indicating migration), eosinophil cationic protein (marker of activated eosinophil granulocytes) and C-reactive protein (marker of systemic inflammation). However, none of these biomarkers are specific for asthma. Further standardization of the known pulmonary biomarkers of local inflammation and identification of new ones will allow for longitudinal follow-up of inflammation in children with asthma.

Age-related macular degeneration (AMD) is a sight threatening eye disease that affects millions of humans over the age of 65 years. It is considered to be the major cause of irreversible blindness in the elderly population in the developed world. The disease is prevalent in Europe and the United States, which has a large number of individuals of European descent. AMD is characterized by a progressive loss of central vision attributable to degenerative and neovascular changes that occur in the interface between the neural retina and the underlying choroid. This location contains the retinal photoreceptors, the retinal pigmented epithelium, a basement membrane complex known as Bruch’s membrane and a network of choroidal capillaries. AMD is increasingly recognized as a complex genetic disorder where one or more genes contribute to an individual’s susceptibility to development of the condition, while the prevailing view is that the disease stems from the interaction of multiple genetic and environmental factors. Although it has been proposed that a threshold event occurs during normal aging, the sequelae of biochemical, cellular, and molecular events leading to AMD are not fully understood. Here, we review the clinical aspects of AMD and summarize the genes which have been reported to have a positive association with the disease.

Laboratory data play a pivotal role in the clinical decision-making process. Major transformations have occurred in laboratory medicine in recent decades. To face the economic pressures, hospital laboratories are forced to enhance efficiency. Decisions on policy and practice take place at many levels. However, decision-making often does not follow Evidence Based Laboratory Medicine principles. Also, the literature shows limited influence of economic evaluations on health care decisions and diagnostic processes. Several barriers to the use of economic evaluation in decision-making process have been identified, and guidelines tend to focus on issues of effectiveness and have not explicitly considered broader issues, particularly cost. As an example, we analyzed recommendations on the use of brain natriuretic peptide (BNP) or N-terminal fragment of the prohormone BNP (NT-proBNP) in patients with chronic heart failure. All guidelines recommend the use of BNP if available. Nevertheless, none included economic data explicitly, even if economic information exists in the literature. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group, propose using a balance sheet approach, one way of helping decision makers to explicitly consider resource use along with other outcomes when making recommendations. Key aspects of GRADE, such as the explicit presentation of information and the quality evaluation of the economic data can help overcome barriers in the use of economic evaluations in the decision-making in process. This approach can help to give health decision makers, clinical guideline panels and patients, a better appreciation of the overall health benefits, harms and costs of laboratory tests.

Background: Permissible limits of analytical imprecision and bias are usually derived either from biological variability or from the state of the art. Both concepts require information from external sources which often lack transparency and are difficult to integrate in medical decision-making. Additionally, physicians may be interested in knowing the probability of decision errors due to analytical uncertainty. Therefore, an approach was developed which combines all three concepts. Methods: The empirical (observed) biological variation was derived from reference ranges used by the laboratory (CV E ). CV E was corrected to get the biological variation in the theoretical absence of analytical imprecision (CV C ). Relatively simple equations were derived from the relationship between biological variation and the analytical imprecision (CV A ) to calculate permissible imprecision and bias. Five quality classes are proposed for the various analytes reflecting the false-positive error rates (FPR). These classes characterize analytical procedures according to their theoretical specificity (FPR). Thus, the new approach combines the theoretical base of biological variation with the technical state-of-the-art. Results and conclusions: As practical examples, the permissible imprecision and bias limits were estimated for a selection of quantities. The limits found were more realistic than present proposals based on Cotlove’s rule (fixed fraction of biological variation), but slightly more stringent than national consensus values based on the state-of-the-art. Imprecision and bias do not affect FPR equally, and, therefore, should be assessed separately. It is proposed to insert monthly imprecision and bias results calculated after each control cycle in a table with five quality classes. This table provides a simple overview of the analytical quality performance of the entire laboratory with one glance and can be handled on the Excel platform.

The Stockholm conference held in 1999 on “Strategies to set global analytical quality specifications (AQS) in laboratory medicine” reached a consensus and advocated the ubiquitous application of a hierarchical structure of approaches to setting AQS. This approach has been widely used over the last decade, although several issues remain unanswered. A number of new suggestions have been recently proposed for setting AQS. One of these recommendations is described by Haeckel and Wosniok in this issue of Clinical Chemistry and Laboratory Medicine . Their concept is to estimate the increase in false-positive results using conventional population-based reference intervals, the delta false-positive rate due to analytical imprecision and bias, and relate the results directly to the current analytical quality attained. Thus, the actual estimates in the laboratory for imprecision and bias are compared to the AQS. These values are classified in a ranking system according to the closeness to the AQS, and this combination is the new idea of the proposal. Other new ideas have been proposed recently. We wait, with great interest, as should others, to see if these newer approaches become widely used and worthy of incorporation into the hierarchy.

Background: Obtaining fetal DNA or RNA by either chorionic villus sampling (CVS) or amniocentesis is currently, the gold standard prenatal diagnosis. However, these invasive procedures carry risk of miscarriage. A reliable method for non-invasive prenatal diagnosis (NIPD) has long been sought to reduce the risk of miscarriage. Methods: Cell-free fetal RNA was extracted from the plasma of peripheral blood from 121 women 9–20 weeks of pregnancy. Five single nucleotide polymorphism (SNP) loci in PLAC4 gene were analyzed by reverse transcriptase multiplex ligation-dependent probe amplification (RT-MLPA), followed by capillary electrophoresis. Karyotype analysis was used for confirmation of prenatal diagnosis of trisomy 21. Results: Of 121 samples, 23 were diagnosed with trisomy 21, 87 with normal ploidy, nine had all five SNP loci homozygous and two had one heterozygous SNP locus. Comparing with karyotype analysis, the diagnostic sensitivity and specificity of RT-MLPA were 92% and 100%, respectively. Conclusions: RT-MLPA is a convenient and reliable method for the diagnosis of trisomy 21. We have shown that this method has good specificity, high sensitivity, and high throughput, making this technique applicable for NIPD in clinical practice.

Background: We report an evaluation of the Menarini/ARKRAY ADAMS A1c HA-8180V analyser (HA-8180V), the fifth generation Menarini/ARKRAY ion-exchange HPLC for the measurement of HbA 1c . Methods: We evaluated the analytical performance, the measurement of haemoglobin variants and the performance in comparison to major analytical methods. Results: Within-run, between-run and total CV were 0.2%, 0.4% and 0.7% at low HbA 1c concentrations and 0.2%, 0.2% and 0.4% at high HbA 1c concentrations, respectively. Trueness revealed a maximum deviation of 0.8 mmol/mol (IFCC units) or 0.1% (NGSP units) over the relevant analytical range. Linearity, carry-over and linear drift were excellent. Labile-HbA 1c , carbamylated haemoglobin, icteric samples and variation in hematocrit did not affect HbA 1c outcome. Haemoglobin variants AS, AC and F do not affect HbA 1c outcome and are explicitly identified and correctly quantified. HbA 1c can not be measured in samples with AE and AD, but these variants are identified correctly. In comparison to other methods used at present, the HA-8180V shows excellent performance. Conclusions: The HA-8180V performs at a high level and is fit for any clinical application.

Background : Measurement of HbA1c is the most important parameter to assess glycemic control in diabetic patients. Different point-of-care devices for HbA1c are available. The aim of this study was to evaluate two point-of-care testing (POCT) analyzers (DCA Vantage from Siemens and Afinion from Axis-Shield). We studied the bias and precision as well as interference from carbamylated hemoglobin. Methods : Bias of the POCT analyzers was obtained by measuring 53 blood samples from diabetic patients with a wide range of HbA1c, 4%–14% (20–130 mmol/mol), and comparing the results with those obtained by the laboratory method: HPLC HA 8160 ® Menarini. Precision was performed by 20 successive determinations of two samples with low 4.2% (22 mmol/mol) and high 9.5% (80 mmol/mol) HbA1c values. The possible interference from carbamylated hemoglobin was studied using 25 samples from patients with chronic renal failure. Results : The means of the differences between measurements performed by each POCT analyzer and the laboratory method (95% confidence interval) were: 0.28% (p<0.005) (0.10–0.44) for DCA and 0.27% (p<0.001) (0.19–0.35) for Afinion. Correlation coefficients were: r=0.973 for DCA, and r=0.991 for Afinion. The mean bias observed by using samples from chronic renal failure patients were 0.2 (range –0.4, 0.4) for DCA and 0.2 (–0.2, 0.5) for Afinion. Imprecision results were: CV=3.1% (high HbA1c) and 2.97% (low HbA1c) for DCA, CV=1.95% (high HbA1c) and 2.66% (low HbA1c) for Afinion. Conclusions : Both POCT analyzers for HbA1c show good correlation with the laboratory method and acceptable precision.

Background: The dogma of establishing intra-laboratory reference limits (RLs) and their periodic review cannot be fulfilled by most laboratories due to the expenses involved. Thus, most laboratories adopt external sources for their RLs, often neglecting the problems of transferability. This is particularly problematic for analytes with a large diversity of existing RLs, as for example thyrotropin (TSH). Several attempts were taken to derive RLs from the large data pools stored in modern laboratory information systems. These attempts were further developed to a more sophisticated indirect procedure. The new approach can be considered a combined concept because it pre-excludes some subjects by direct criteria a-posterior. In the current study, the applicability of the new concept for modern protein bindings assays was examined for estimating RLs of serum and plasma TSH with data sets from several German and Italian laboratories. Methods: A smoothed kernel density function was estimated for the distribution of the total mixed data of the sample group (combined data of non-diseased and diseased subjects). It was assumed that the “central” part of the distribution of all data represents the non-diseased (“healthy”) population. The central part was defined by truncation points using an optimisation method, and was used to estimate a Gaussian distribution of the values of presumably non-diseased subjects after Box-Cox transformation of the empirical data. This distribution was now considered as the distribution of the non-diseased subgroup. The percentiles of this parametrical distribution were calculated to obtain RLs. Results: RLs determined by the indirect combined decomposition technique led to similar RLs as found by several recent study reports using a direct method according to international recommendations. Furthermore, the RLs obtained from 13 laboratories in two different European regions re-flected the well-known differences of various analytical procedures. Stratification for gender and age was necessary in contrast to earlier reports. With increasing age, an increase of the upper RL and the reference range was observed. Hospitalisation also affected the RLs. Common RLs appeared acceptable only within the same analytical systems. Some laboratories used RLs which were not appropriate for the population served. Conclusions: The proposed strategy of combining exclusion criteria with a resolution technique led to retrospective RLs from intra-laboratory data pools for TSH which were comparable with directly determined RLs. Differences between laboratories were due primarily to the well-known bias of the different analytical procedures and to the status of the population.

Background: Blood gas analysis (BGA), including measurement of ionized calcium, is performed routinely in patients with end stage renal disease on renal replacement therapy, especially when using citrate for regional anticoagulation. After installation of a new blood gas analyzer (RAPIDpoint ® 405; BGA), we observed lower ionized calcium concentrations in a few patients without signs of hypocalcemia, whereas calcium concentrations were normal using a standard laboratory method. Pseudohypocalcemia was of limited duration and correlated with the short-term intake of sodium perchlorate monohydrate (Irenat ® ). Methods: We prepared dilution series from whole blood samples and stock solutions of calcium and perchlorate with different concentrations of ionized calcium and perchlorate. Measurement of ionized calcium concentrations was performed using two different blood gas analyzers (RAPIDpoint ® 405; BGA and Roche AVL 9180; standard laboratory method). Results: After addition of different amounts of perchlorate, significant lower ionized calcium concentrations were measured with BGA compared to the standard laboratory method using either preparations from whole blood samples or stock solutions. The addition of potassium or methylene blue known to complex perchlorate had no effect on the concentrations of ionized calcium measured with BGA. Using different mathematical methods, a calculation of the “real” ionized calcium concentration from the value measured with BGA was not possible. Conclusions: Based on our experiments, we confirm the hypothesis that perchlorate can influence the measurement of ionized calcium by BGA. As the effect depends on the ion selective electrode that is used, it is advisable to test the blood gas analyzer with calcium and perchlorate solutions.

Background: Accurate cholesterol measurements are essential for the prevention and management of cardiovascular diseases. Quality assurance of cholesterol measurements requires reference methods. Methods: An isotope dilution liquid chromatography mass spectrometric (ID/LC/MS) method was developed. Serum samples were sampled volumetrically using automated dilutors, treated with potassium hydroxide and equilibrated with 3,4- 13 C 2 cholesterol. The natural cholesterol and the internal standard were extracted with hexane and oxidized to cholest-4-en-3,6-diones with chromic acid. The oxidation products were separated on reversed phase LC and detected by tandem MS. The method was calibrated using aqueous cholesterol calibrators and the calibration function was established with a polynomial regression. Results: The correlation coefficients of the calibration curves were always >0.9999. The coefficients of variation (CV) of the volumetric sampling and the LC/MS analysis averaged 0.22% and 0.50%, respectively, and the total measurement CV was 0.60%. Other sources of measurement uncertainty were minor. Results on certified reference materials agreed within 1% of the certified values. Conclusions: An ID/LC/MS method for serum cholesterol has been developed. The method is simple and accurate and may be used as a candidate reference method.

Background: The specificity of screening for congenital adrenal hyperplasia by direct measurement of 17-hydroxyprogesterone in filter paper dried blood spot samples by immunoassay is low and has a high false-positive rate. In order to reduce the false-positive rate of this test, we developed a rapid, robust, specific confirmatory procedure in which cortisol, 4-androstene-3,17-dione and 17-hydroxyprogesterone were measured simultaneously by ultra-performance liquid chromatography-tandem mass spectrometry. Methods: After extraction, samples were analysed by ultra-performance liquid chromatography-tandem mass spectrometry and 17-hydroxyprogesterone was quantified accurately. Other steroids were determined using stable deuterated internal standards. In total, 25 patient blood spot samples and 92 control samples were analysed. Results: The assay was linear for 17-hydroxyprogesterone, with a coefficient of determination >0.997 and imprecision ≤6.5%. An upper limit of normal for 17-hydroxyprogester-one of 4.45 nmol/L was established by analysing a cohort of samples from unaffected newborns. In addition, a cut-off of 3.5 for the peak areas ratio (17-hydroxyprogesterone+4-androstene-3,17-dione)/cortisol, allows confirmation of the affected steroidogenic enzyme. Conclusions: A high throughput method for the detection of steroids related to congenital adrenal hyperplasia has been developed, allowing the false-positive rate associated with screening for 17-hydroxyprogesterone by immunoassay to be determined.

Background: Plasma cells are one of the end products of the B-lymphocyte mediated immune response. These cells normally reside in the bone marrow or some peripheral lymphoid tissues. Increased numbers of plasma cells in the blood, usually indicates pathology such as infection, auto-immunity or haematological malignancy. Therefore, the ability to measure plasma cells (PCs) on an automated cell analyzer might be advantageous. Methods: The performance of the Sysmex XE-5000 leukocyte differential channel [high fluorescent lymphocyte count (HFLC) area] was evaluated for the ability to detect plasma cells in peripheral blood and compared to the detection of plasma cells by flow cytometric analyses. Results: Our results show that the HFL count from the XE-5000 correlates (R 2 =0.8) with the number of PCs in peripheral blood, but detects PCs with moderate to good sensitivity (88.9%) and specificity (87.8%). Conclusions: The Sysmex XE-5000 is suitable for screening blood samples for the presence of elevated number of plasma cells in peripheral blood, but the actual quantification needs to be confirmed by flow cytometry.

Background: The clottability and the amount of total protein in fibrinogen provide information about qualitative or quantitative alterations. We aimed to evaluate whether capillary zone electrophoresis (CZE) Capillarys II analyzer with the protein 6 buffer is able to estimate the amount of fibrinogen antigen. Methods: Citrated plasmas were assayed for clottable fibrinogen, and any relationship with the β 2 -globulin fraction (percentage of the area under the curve) was evaluated. The integration method used was “tangent skimming” in order to reduce the overestimation due to high protein background. Linearity was optimized according to the ICH Q2R1 recommendations and evaluated using polynomial regression. The precision was computed in accordance with the Clinical and Laboratory Standards Institute EP5-A2 protocol. In patients, clottable fibrinogen (Clauss method) was compared to its protein CZE amount by Passing and Bablok regression and the Bland-Altman plot. Results: The correlation was linear y=0.0744+0.8991x (R 2 =0.9707) within the range of 2.26–17.26 μmol/L. The repeatability and the within-device precision were <15% for three levels of percentage of the β 2 -globulin fraction (1.61%, 3.51%, and 9.24%). In patients, clottable fibrinogen and its protein amount were similar (–0.1779+0.9654x). The ratio activity/protein was 1.08±0.32 (mean±2 SD). Conclusions: CZE with the Capillarys II and the buffer protein 6 is an easy method. It is a good candidate for estimation of the concentration of fibrinogen antigen, which may have diagnostic utility for the screening of quantitative or qualitative fibrinogen abnormalities.

Background: We have empirically noted that many physicians routinely request anti-phospholipid antibodies (aPL) without a correct clinical indication. The aim of this study was to evaluate retrospectively whether aPL testing at our Thrombosis Centre was justified. Methods: Medical records from 520 subjects for aPL screening tests for various clinical conditions were reviewed. The aPL screening tests were: lupus anticoagulant (LA), anti-cardiolipin antibodies (aCL) and anti-β 2 glycoptotein I (aβ 2 GPI). Requests for aPL screening were divided into justified, potentially justified or not adequately justified. Results: aPL testing requests were considered justified in 358 (69%) patients, potentially justified in 66 (12.6%) and not adequately justified in 96 (18.4%). LA was positive in 65 (18%) of justified requests and in only one (1%) of the 96 potentially justified requests. None of the 66 not adequately justified for aPL testing was positive for LA. aβ 2 GPI was positive in 63 (17.6%) of the 358 justified, in four (6%) of the 66 potentially justified and in five (5.2%) of the 96 not adequately justified requests; aCL IgG were positive in 59 (16.4%) of the 358 justified and in five (7.5%) and six (6.2%) of the potentially justified and not adequately justified requests, respectively. The presence of the triple aPL positivity was found exclusively in the justified requests. Conclusions: This study suggests that requests for aPL tests should be addressed more adequately. This work could be an example of how to focus attention on requests for laboratory tests especially on the basis of valid clinical criteria before the analyte is measured.

Background: Lung cancer is a leading cause of cancer deaths. Unfortunately, no effective early screening modality exists for lung cancer. We aimed to evaluate the prevalence of HOXA9 promoter methylation in tissue and induced sputum samples from Korean patients with lung cancer. Methods: Using pyrosequencing, HOXA9 methylation was analyzed for 40 pairs of primary lung cancer and normal tissues and 185 induced sputum specimens, including 76 patients with lung cancer. Results: The methylation of HOXA9 in lung cancer tissue was significantly higher compared with normal tissues (67.4%±17.6% vs. 23.6%±10.3%, respectively; p<0.001). With a cut-off of >45.6% of HOXA9 gene methylation in tissues, the sensitivity was 90.5% and the specificity was 97.5%. In induced sputum specimens, the HOXA9 gene in lung cancer patients was significantly more hypermethylated compared with patients with benign lung diseases and the healthy group (23.4%±15.9%, 14.9%±7.9%, and 9.7%±5.0%, respectively; p<0.001). Conclusions: The HOXA9 gene was hypermethylated in 32 of 40 tumors (80%), especially in early stages of lung cancer. HOXA9 methylation could be a potential biomarker to aid early detection and prognosis.

Background: Matrix metalloproteinase-9 ( MMP-9 ) shows significant involvement with cancer invasion and therefore has prognostic significance. Tumor tissues from nasopharyngeal carcinoma (NPC) patients are not easy to access, and peripheral blood mononuclear cells (PBMC) are a valuable alternative. This study compared the expression levels of MMP-9 in PBMCs from NPC patients and healthy controls and evaluated the potential as a prognostic biomarker for NPC patients. Methods: MMP-9 mRNA concentrations in PBMCs from 146 NPC patients and 110 healthy controls were measured using quantitative real-time PCR. Differences in MMP-9 expression between NPC patients and controls were evaluated using non-parametric tests, and the effects of different clinical characteristics on MMP-9 expression were also analyzed. The Kaplan-Meier test and Cox regression model were used to explore the association between MMP-9 expression and overall survival of NPC patients. Results: MMP-9 mRNA levels in PBMCs were significantly higher in NPC patients than in healthy controls (p<0.001). Increased MMP-9 expression was associated with the following clinical characteristics: advanced clinical stage (p<0.001), T stage (p=0.016), N stage (p=0.002), histology type (p=0.037), and poor overall survival (p=0.049). Conclusions: MMP-9 mRNA expression in PBMCs from NPC patients is increased and associated with the clinical characteristics and overall survival. It supports the belief that MMP-9 may contribute to the progression of NPC.

Background: Golgi protein-73 (GP73) and fucosylated proteins have been proposed as potential serum markers for liver disease and/or hepatocellular carcinoma (HCC). The purpose of this study was to compare the sensitivity and specificity of serum GP73 and fucosylated hemopexin (Fuc-HPX) with α-fetoprotein (AFP) and with protein induced by the absence of vitamin K or antagonist-II (PIVKA-II) for diagnosing chronic hepatitis, cirrhosis, and HCC. Methods: The concentration of GP73 in human sera was determined using an enzyme-linked immunosorbent assay employing mouse monoclonal and rabbit polyclonal GP73 antibodies. Fuc-HPX was detected using a lectin chemiluminescence-linked immunosorbent assay using a mouse monoclonal anti-hemopexin antibody and Aleuria aurantia lectin. A total of 229 serum samples from patients with chronic hepatitis, cirrhosis, and HCC, as well as from normal individuals were evaluated using these four markers. Results: GP73 and Fuc-HPX showed significantly higher values in samples from patients with cirrhosis and HCC than in samples from patients with hepatitis and from normal individuals. The areas under the curves (AUCs) for GP73, Fuc-HPX, AFP, and PIVKA-II were 0.90, 0.77, 0.74, and 0.88, respectively, for liver cirrhosis and HCC samples vs. hepatitis and normal samples. The AUCs of GP73, Fuc-HPX, AFP, and PIVKA-II were 0.78, 0.72, 0.81, and 0.90, respectively, for HCC samples vs. all other samples. Conclusions: PIVKA-II showed superior sensitivity and specificity for HCC compared with the other three markers. GP73 may be useful for detecting cirrhosis as a risk factor for HCC. Fuc-HPX showed inferior sensitivity and specificity compared to the other markers.

Background: An effective prevention strategy for heart failure in primary care requires a reliable screening tool for asymptomatic ventricular dysfunction. Preliminary data indicate that B-type natriuretic peptide (BNP) may be suitable for this task. However, for the most effective use of this peptide, the interrelationships between associated risk factors and their therapies on BNP, and in particular their magnitude of effect, needs to be established in a large primary care population. Therefore, the objective of the study was to establish the extent of the association between BNP, cardiovascular risk factors and their therapies. Methods: BNP measurement and clinical review was preformed on 1122 primary care patients with cardiovascular risk factors. Multivariate analyses identified significant associates of BNP concentrations which were further explored to establish the magnitude of their association. Results: Associates of BNP were age (1.36-fold increase in BNP/decade), female (1.28), β-blockers (1.90), myocardial infarction (1.36), arrhythmia (1.98), diastolic blood pressure; all p<0.01. A novel method was devised that plotted median BNP per sliding decade of age for the various combinations of these principal associates. Conclusions: The data presented underline the importance of considering several clinical and therapeutic factors when interpreting BNP concentrations. Most of these variables were associated with increased concentrations, which may in part explain the observed false-positive rates for detecting ventricular dysfunction using this peptide. Furthermore, the design of studies or protocols using BNP as an endpoint or a clinical tool should take particular account of these associations. This analysis provides the foundation for age, risk factor and therapy adjusted reference ranges for BNP in this setting.

Background: A homocysteine (Hcy) metabolite, thioester Hcy-thiolactone, whose reaction with protein lysine residues affords N-homocysteinylated proteins, has been implicated in cardiovascular disease. Proteolytic turnover of N-homocysteinylated proteins generates the isopeptide Nɛ-homocysteinyl-lysine (N-Hcy-Lys). Methods: We determined N-Hcy-Lys in serum and a NO syntase inhibitor asymmetric dimethylarginine (ADMA), as well as symmetric dimethylarginine (SDMA) and glutathione in plasma by high performance liquid chromatography in 52 consecutive patients with acute myocardial infarction (AMI) recruited within the first 12 h following onset of chest pain. Associations of N-Hcy-Lys with markers of thrombin generation, oxidative stress, enhanced inflammation, fibrinolysis, and autoantibodies against homocysteinylated proteins were also analyzed. Results: N-Hcy-Lys concentrations, detectable in 45 (86.5%) patients (>0.1 μmol/L), were 127.3% higher compared with healthy controls. N-Hcy-Lys correlated with ADMA (r=0.50; p<0.001), SDMA (r=0.43; p<0.01), glutathione (r=0.37; p<0.05), fibrinogen (r=0.39; p<0.01) and plasminogen activator inhibitor-1 (r=0.32; p<0.05), but not with plasma total Hcy, anti-N-Hcy-protein autoantibodies, vitamin B 12 , folate, interleukin-6, plasma thrombin-antithrombin (TAT) complexes, prothrombin fragments F1+2 or 8-isoprostaglandin F 2α a marker of oxidative stress. Conclusions: N-Hcy-Lys is increased in AMI patients and its formation is linked with the nitric oxide synthase inhibitor ADMA.