Search results for "Protein precursor"
showing 10 items of 169 documents
Utility of Procalcitonin for Diagnosis of Superimposed Infections in Patients With Acute Heart Failure.
2016
Respiratory infections are well-known precipitant factors for heart failure decompensations. Nevertheless, the diagnosis of life-threatening infections, such as pneumonia, is challenging. Pneumonia and acute heart failure often display overlapping clinical findings and, in other cases, more accurate infection-related findings are missing. In recent years, procalcitonin has emerged as a promising tool for early and accurate diagnosis of pneumonia and, interestingly, for guiding antibiotic therapy in patients with acute heart failure. We discuss two cases of acute heart failure with high procalcitonin on admission and different clinical outcomes. In this setting, procalcitonin may be a useful…
Procalcitonin and community-acquired pneumonia (CAP) in children
2015
The role of procalcitonin (PCT) as a biomarker for sepsis in adults is well documented, while its role in infections affecting neonatal children remains controversial. Among these infections, Community-Acquired pneumonia (CAP) has been studied extensively, because it's the second cause of death in children in developing countries, and one of the most frequent causes of hospitalization in industrialized countries. The PubMed database and the Cochrane Library were used to search for the following keywords: CAP, procalcitonin, and children. Thirteen articles were studied to determine the role of PCT in CAP management, specifically its usefulness for distinguishing pneumococcal infections from …
Procalcitonin levels in plasma in oncohaematologic patients with and without bacterial infections.
2004
Abstract Background: The flogosis markers currently in use show both low sensitivity and specificity, particularly in neoplastic and degenerative diseases. Procalcitonin (PCT) is a pro-peptide of calcitonin produced mainly but not only in the C-cells of the thyroid glands and, as several studies show, PCT levels in plasma increase during infections. Bacterial infections are also the main cause of death in oncological patients. Furthermore, in patients with leukaemia in chemotherapy recovery, infections often induce relapses. The aim of the present study is to detect PCT levels in plasma in oncohaematologic patients with and without infections. Methods: The study was carried out on 54 patien…
Holo-APP and G-protein-mediated signaling are required for sAPPa-induced activation of the Akt survival pathway
2014
International audience; Accumulating evidence indicates that loss of physiologic amyloid precursor protein (APP) function leads to reduced neuronal plasticity, diminished synaptic signaling and enhanced susceptibility of neurons to cellular stress during brain aging. Here we investigated the neuroprotective function of the soluble APP ectodomain sAPPa (soluble APPa), which is generated by cleavage of APP by a-secretase along the non-amyloidogenic pathway. Recombinant sAPPa protected primary hippocampal neurons and SH-SY5Y neuroblastoma cells from cell death induced by trophic factor deprivation. We show that this protective effect is abrogated in neurons from APP-knockout animals and APP-de…
Inhibitors of Rho-kinase modulate amyloid-β (Aβ) secretion but lack selectivity for Aβ42
2005
Certain non-steroidal anti-inflammatory drugs (NSAIDs) preferentially inhibit production of the amyloidogenic Abeta42 peptide, presumably by direct modulation of gamma-secretase activity. A recent report indicated that NSAIDs could reduce Abeta42 by inhibition of the small GTPase Rho, and a single inhibitor of Rho kinase (ROCK) mimicked the effects of Abeta42-lowering NSAIDs. To investigate whether Abeta42 reduction is a common property of ROCK inhibitors, we tested commercially available compounds in cell lines that were previously used to demonstrate the Abeta42-lowering activity of NSAIDs. Surprisingly, we found that two ROCK inhibitors reduced total Abeta secretion in a dose-dependent m…
Vitamin E transport, membrane incorporation and cell metabolism: Is α-tocopherol in lipid rafts an oar in the lifeboat?
2010
International audience; Vitamin E is composed of closely related compounds, including tocopherols and tocotrienols. Studies of the last decade provide strong support for a specific role of alpha-tocopherol in cell signalling and the regulation of gene expression. It produces significant effects on inflammation, cell proliferation and apoptosis that are not shared by other vitamin E isomers with similar antioxidant properties. The different behaviours of vitamin E isomers might relate, at least in part, to the specific effects they exert at the plasma membrane. alpha-Tocopherol is not randomly distributed throughout the phospholipid bilayer of biological membranes, and as compared with other…
α-Secretase Activity of the Disintegrin Metalloprotease ADAM 10: Influences of Domain Structure
2001
Disintegrin metalloproteases from different organisms form the ADAM (a disintegrin and metalloprotease) family. All members display a common domain organization and possess four potential functions: proteolysis, cell adhesion, cell fusion, and cell signaling. Members of the ADAM family are responsible for the proteolytic cleavage of transmembrane proteins and release of their extracellular domain. The proteolytic process is referred to as ectodomain shedding, which is activated by phorbol esters and inhibited by hydroxamic acid-based inhibitors. We have shown that the disintegrin metalloprotease ADAM 10 has both constitutive and regulated alpha-secretase activity. Expression of a dominant n…
Estrogen-induced cell signalling in a cellular model of Alzheimer's disease.
2003
Alzheimer's disease (AD) is characterised by deposition of a 4 kDa amyloid-beta peptide (Abeta) into senile plaques of the affected brain. Abeta is a proteolytic product of the membrane protein, amyloid precursor protein (APP). An alternative cleavage pathway involves alpha-secretase activity and results in secretion of a 100 kDa non-amyloidogenic APP (sAPPalpha) and therefore a potential reduction in Abeta secretion. We have shown that estrogen induces alpha-cleavage and therefore results in the secretion of sAPPalpha. This secretion is signalled via MAP-kinase and PI-3 kinase signal-transduction pathways. These pathways also have the potential to inhibit the activation of glycogen synthas…
Oxidative stress resistance in hippocampal cells is associated with altered membrane fluidity and enhanced nonamyloidogenic cleavage of endogenous am…
2010
Reactive oxygen species (ROS) have important roles as signaling molecules in the regulation of a variety of biological processes. On the other hand, chronic oxidative stress exerted by ROS is widely considered a causative factor in aging. Therefore, cells need to be able to adapt to a chronic oxidative challenge and do so to a certain cell-type-specific extent. Recently, we have shown in oxidative-stress-resistant cell lines, HT22(H2O2) and HT22(Glu), derived from the neuronal cell line HT22 by chronic exposure to sublethal concentrations of H(2)O(2) and glutamate, that, in addition to the known antioxidant defense mechanisms, e.g., activation of antioxidant enzymes or up-regulation of heat…
Carotenoid binding sites in LHCIIb
2000
The major light-harvesting complex of photosystem II can be reconstituted in vitro from its bacterially expressed apoprotein with chlorophylls a and b and neoxanthin, violaxanthin, lutein, or zeaxanthin as the only xanthophyll. Reconstitution of these one-carotenoid complexes requires low-stringency conditions during complex formation and isolation. Neoxanthin complexes (containing 30–50% of the all-trans isomer) disintegrate during electrophoresis, exhibit a largely reduced resistance against proteolytic attack; in addition, energy transfer from Chl b to Chl a is easily disrupted at elevated temperature. Complexes reconstituted in the presence of either zeaxanthin or lutein contain nearly …