N-Terminal-proBNP (NT-proBNP) as an indicator of cardiac dysfunction. A study in patients presenting with suspected cardiac disorders.

BACKGROUND: Natriuretic peptides represent a novel diagnostic tool in the assessment of cardiac dysfunction. METHODS: A total of 473 consecutive referred patients presenting to 18 cardiologists for the assessment of their cardiac state were recruited for the study. Patients received a medical history, a physical examination an electrocardiogram and an echocardiogram where left ventricular ejection fraction was recorded. RESULTS: NT-proBNP was found to correlate with left ventricular ejection fraction (LVEF), level of symptoms (NYHA classification), history of angina pectoris (AP) and myocardial infarction (AMI). Atrial fibrillation (AF) and thyroid dysfunction as well as renal impairment were shown to influence NT-proBNP levels. CONCLUSION: The study supports the hypothesis that NT-proBNP determination contributes to the assessment of patients presenting to cardiologists.

Classification of signatures of Bovine Spongiform Encephalopathy in serum using infrared spectroscopy.

Signatures of Bovine Spongiform Encephalopathy (BSE) have been identified in serum by means of "Diagnostic Pattern Recognition (DPR)". For DPR-analysis, mid-infrared spectroscopy of dried films of 641 serum samples was performed using disposable silicon sample carriers and a semi-automated DPR research system operating at room temperature. The combination of four mathematical classification approaches (principal component analysis plus linear discriminant analysis, robust linear discriminant analysis, artificial neural network, support vector machine) allowed for a reliable assignment of spectra to the class "BSE-positive" or "BSE-negative". An independent, blinded validation study was carried out on a second DPR research system at the Veterinary Laboratory Agency, Weybridge, UK. Out of 84 serum samples originating from terminally-ill, BSE-positive cattle, 78 were classified correctly. Similarly, 73 out of 76 BSE-negative samples were correctly identified by DPR such that, numerically, an accuracy of 94.4 % can be calculated. At a confidence level of 0.95 (alpha = 0.05) these results correspond to a sensitivity > 85% and a specificity > 90%. Identical class assignment by all four classifiers occurred in 75% of the cases while ambiguous results were obtained in only 8 of the 160 cases. With an area under the ROC (receiver operating charateristics) curve of 0.991, DPR may potentially supply a valuable surrogate marker for BSE even in cases in which a deliberate bias towards improved sensitivity or specificity is desired. To the best of our knowledge, DPR is the first and--up to now--only method which has demonstrated its capability of detecting BSE-related signatures in serum.