State of the art of immunoassay methods for B-type natriuretic peptides: An update

The aim of this review article is to give an update on the state of the art of the immunoassay methods for the measurement of B-type natriuretic peptide (BNP) and its related peptides. Using chromatographic procedures, several studies reported an increasing number of circulating peptides related to BNP in human plasma of patients with heart failure. These peptides may have reduced or even no biological activity. Furthermore, other studies have suggested that, using immunoassays that are considered specific for BNP, the precursor of the peptide hormone, proBNP, constitutes a major portion of the peptide measured in plasma of patients with heart failure. Because BNP immunoassay methods show large (up to 50%) systematic differences in values, the use of identical decision values for all immunoassay methods, as suggested by the most recent international guidelines, seems unreasonable. Since proBNP significantly cross-reacts with all commercial immunoassay methods considered specific for BNP, manufacturers should test and clearly declare the degree of cross-reactivity of glycosylated and non-glycosylated proBNP in their BNP immunoassay methods. Clinicians should take into account that there are large systematic differences between methods when they compare results from different laboratories that use different BNP immunoassays. On the other hand, clinical laboratories should take part in external quality assessment (EQA) programs to evaluate the bias of their method in comparison to other BNP methods. Finally, the authors believe that the development of more specific methods for the active peptide, BNP1–32, should reduce the systematic differences between methods and result in better harmonization of results

The utility of B-type natriuretic peptide in the diagnosis of heart failure in the emergency department: a systematic review

<p>Abstract</p> <p>Background</p> <p>Dyspnea is a common chief complaint in the emergency department (ED); differentiating heart failure (HF) from other causes can be challenging. Brain Natriuretic Peptide (BNP) is a new diagnostic test for HF for use in dyspneic patients in the ED. The purpose of this study is to systematically review the accuracy of BNP in the emergency diagnosis of HF.</p> <p>Methods</p> <p>We searched MEDLINE (1975–2005) supplemented by reference tracking. We included studies that reported the sensitivity and specificity of BNP for diagnosing HF in ED patients with acute dyspnea. Two reviewers independently assessed study quality. We pooled sensitivities and specificities within five ranges of BNP cutoffs.</p> <p>Results</p> <p>Ten studies including 3,344 participants met inclusion criteria. Quality was variable; possible verification or selection bias was common. No studies eliminated patients with obvious medical causes of dyspnea. Most studies used the Triage BNP assay; all utilized a clinical reference standard. Pooled sensitivity and specificity at a BNP cutoff of 100–105 pg/ml were 90% and 74% with negative likelihood ratio (LR) of 0.14; pooled sensitivity was 81% with specificity of 90% at cutoffs between 300 and 400 pg/ml with positive LR of 7.6.</p> <p>Conclusion</p> <p>Our analysis suggests that BNP has moderate accuracy in detecting HF in the ED. Our results suggest utilizing a BNP of less than 100 pg/ml to rule out HF and a BNP of greater than 400 pg/ml to diagnose HF. Many studies were of marginal quality, and all included patients with varying degrees of diagnostic uncertainty. Further studies focusing on patients with diagnostic uncertainty will clarify the real-world utility of BNP in the emergency management of dyspnea.</p

A mini foxtail millet with an Arabidopsis-like life cycle as a C4 model system

Over the past few decades, several plant species, including Arabidopsis thaliana, Brachypodium distachyon and rice (Oryza sativa), have been adopted as model plants for various aspects of research. These species, especially Arabidopsis, have had vital roles in making fundamental discoveries and technological advances 1. However, all these model plants use C 3 photosynthe-sis, and discoveries made in these species are not always transferable to, or representative of, C 4 plants such as maize (Zea mays), sor-ghum (Sorghum bicolor) and millets, which are efficient fixers of atmospheric CO 2 into biomass. Thus, it is critical to develop a new model system for studies in these and many other C 4 plants 2. Foxtail millet (S. italica) is a cereal crop that was domesticated from its wild ancestor, green foxtail (Setaria viridis). These two species are evolutionarily close to several bioenergy crops, including switchgrass (Panicum virgatum), napiergrass (Pennisetum purpu-reum) and pearl millet (Pennisetum glaucum), and major cereals such as sorghum, maize and rice 3. In addition, extensive genetic diversity exists in Setaria, with approximately 30,000 accessions preserved in China, India, Japan and the United States 3 as valuable resources for gene-function dissection and elite-allele mining 4. In recent years, the whole-genome sequences of foxtail millet and green foxtail have been made available 5-9 , and both species have been proposed as C 4 model plant systems 3,6. Between these two species, foxtail millet is more suitable as a model plant due to the seed shattering and dor-mancy in green foxtail. Nevertheless, the relatively long life cycle (usually 4-5 months per generation) and large plant size (1-2 m in height) limit the use of foxtail millet as a model plant 3,10-12. To overcome such limitations, we have recently developed a large fox-tail millet ethyl methane sulfonate (EMS)-mutagenized population using Jingu21, a high-yield, high-grain-quality elite variety widely grown in north China in the past few decades. From the mutant population, we identified a miniature mutant (dubbed xiaomi) with a life cycle similar to that of Arabidopsis. Subsequently, we developed genomics and transcriptomics resources and a protocol for efficient transformation of xiaomi, as essential parts of the toolbox for the research community