Inappropriateness in laboratory medicine: An elephant in the room?

Appropriateness of diagnostic testing can be conventionally described as prescription of the right test, using the right method, at the right time, to the right patient, with the right costs and for producing the right outcome. There is ongoing debate about the real burden of inappropriateness in laboratory diagnostics. The media coverage of this issue has also recently led to either over- or under-emphasizing the clinical, organizational and economic consequences. This is quite problematic, inasmuch as some reliable data are available in the current scientific literature, showing that inappropriateness of laboratory testing can be as high as 70%. This is especially evident for, though not limited to, cancer biomarkers testing, in which the practice of avoidable tests ordering is dramatically magnified. The reasons beyond inappropriateness are many and multifaceted, entailing wrong habits, resistance to changes, poor culture, insufficient education and healthcare inefficiencies. There are many unfavorable consequences attributable to avoidable testing, including unjustified incremental costs, derangement of laboratory efficiency and potential patient safety issues. The tentative solutions to this important problem necessitate that policymakers, local hospital administrators, laboratory professionals, clinicians, patients' associations and diagnostic companies join the efforts and embark in the same landmark effort for disseminating a better culture of appropriateness

Biochemical biomarkers and neurodegenerative diseases

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A rapid spectroscopic method to detect the fraudulent treatment of tuna fish with carbon monoxide

Carbon monoxide (CO) can be used to treat fresh meat and fish in order to retain its 'fresh' red colour appearance for a longer period of time. In fact, upon aging, myoglobin is oxidized to met-myoglobin with the concomitant blue-shift and broadening of the Soret maximum, which brings about a change in the colour of the fish, revealing that it is no longer fresh. The use of carbon monoxide, which reacts with the oxy-myoglobin to form a fairly stable cherry red carboxy-myoglobin complex may mask spoilage, because the CO-complex can be stable beyond the microbiological shelf life of the meat. The presence of CO in tuna fish has been investigated by optical spectroscopy as the formation of the CO adduct can be easily detected by the combined analysis of electronic absorption spectra in their normal and second derivative modes, monitoring the intense Soret band at 420 nm. The presence of met- and oxy-myoglobin can obscure the presence of small amounts of the CO adduct; however, it can be revealed by chemically reducing the met- and oxy-forms to the deoxy-form in an anaerobic environment. This spectroscopic method provides a qualitatively rapid laboratory screening procedure for food control to unmask the presence of CO in frozen or fresh fish. (c) 2006 Elsevier Ltd. All rights reserved

A genetic study on subtropical Anadenanthera colubrina (Vell.) Brenan var. cebil (Griseb.) Altschul tree from Northwestern Argentina

Anadenanthera colubrina (Vell.) Brenan var. cebil (Griseb.) Altschul is a tree species in South America important for its cultural, economic, and medicinal uses. In addition, it represents a trace in memory of the forests that have decreased over the years and for this reason it is not only interesting to study but also important to preserve the tree species for future generations. In this paper, we have characterized the genetic diversity of four populations. We collected seeds from four different sites: San Bernardo (B), El Cebilar (C), Met\ue1n (M), and El Gallinato (G) in Salta Province, North Argentina. We then compared the intergenic transcribed sequences of ribosomal DNA, a known genetic molecular marker. Our previous results, obtained through the morphological and genetic analysis of only four individuals (one for each zone), have showed that the individuals from B and M sites were more similar to each other as well as the individuals from G and C sites. In this paper, a larger number of individuals (25) were characterized and their phylogenetic relationships were computed. The results confirmed the previously found similarities

Somatostatin: A Novel Substrate and a Modulator of Insulin-Degrading Enzyme Activity

Insulin-degrading enzyme (IDE) is an interesting pharmacological target for Alzheimer's disease (AD), since it hydrolyzes beta-amyloid, producing non-neurotoxic fragments. It has also been shown that the somatostatin level reduction is a pathological feature of AD and that it regulates the neprilysin activity toward beta-amyloid. In this work, we report for the first time that IDE is able to hydrolyze somatostatin [k(cat) (s(-1)) = 0.38 (+/-0.05); K-m (M) = 7.5 (+/-0.9) x 10(-6)] at the Phe6-Phe7 amino acid bond. On the other hand, somatostatin modulates IDE activity, enhancing the enzymatic cleavage of a novel fluorogenic beta-amyloid through a decrease of the K-m toward this substrate, which corresponds to the 10-25 amino acid sequence of the A beta(1-40). Circular dichroism spectroscopy and surface plasmon resonance imaging experiments show that somatostatin binding to IDE brings about a concentration-dependent structural change of the secondary and tertiary structure(s) of the enzyme, revealing two possible binding sites. The higher affinity binding site disappears upon inactivation of IDE by ethylenediaminetetra acetic acid, which chelates, the catalytic Zn2+ ion. As a whole, these features suggest that the modulatory effect is due to an allosteric mechanism: somatostatin binding to the active site of one IDE subunit (where somatostatin is cleaved) induces an enhancement of IDE proteolytic activity toward fluorogenic beta-amyloid by another subunit. Therefore, this investigation on IDE-somatostatin interaction contributes to a more exhaustive knowledge about the functional and structural aspects of IDE and its pathophysiological implications in the amyloid deposition and somatostatin homeostasis in the brain. (C) 2008 Elsevier Ltd. All rights reserved