How the stomach and the brain work together at rest

Low-frequency electrical waves in the stomach seem to be synchronised with the activity of a newly discovered resting-state network in the human brain

Functional proteomics.

Background: With the increase in the number of genome sequencing projects, there is a concomitant exponential growth in the number of protein sequences whose function is still unknown. Functional proteomics constitutes an emerging research area in the proteomic field whose approaches are addressed towards two major targets: the elucidation of the biological function of unknown proteins and the definition of cellular mechanisms at the molecular level. Methods: The identification of interacting proteins in stable complexes in vivo is essentially achieved by affinity-based procedures. The basic idea is to express the protein of interest with a suitable tag to be used as a bait to fish its specific partners out from a cellular extract. Individual components within the multi-protein complex can then be identified by mass spectrometric methodologies. Results and conclusions: The association of an unknown protein with partners belonging to a specific protein complex involved in a particular mechanism is strongly suggestive of the biological function of the protein. Moreover, the identification of protein partners interacting with a given protein will lead to the description of cellular mechanisms at the molecular level. The next goal will be to generate animal models bearing a tagged form of the bait protein

Limited proteolysis in the investigation of beta2-microglobulin amyloidogenic and fibrillar states.

Amyloid fibrils of patients treated with regular haemodialysis essentially consists of β2-microglobulin (β2-m) and its truncated species ΔN6β2-m lacking six residues at the amino terminus. The truncated fragment shows a higher propensity to self-aggregate and constitutes an excellent candidate for the analysis of a protein in the amyloidogenic conformation. The surface topology and the conformational analysis of native β2-m and the truncated ΔN6β2-m species both in the soluble and in the fibrillar forms were investigated by the limited proteolysis/mass spectrometry strategy. The conformation in solution of a further truncated mutant ΔN3β2-m lacking three residues at the N-terminus was also examined. This approach appeared particularly suited to investigate the regions that are solvent-exposed, or flexible enough to be accessible to protein-protein interactions and to describe the conformation of transient intermediates. Moreover, proteolysis experiments can also be tailored to investigate amyloid fibrils by discriminating the protein regions constituting the unaccessible core of the fibrils and those still flexible and exposed to the solvent. Although native β2-m and ΔN3β2-m shared essentially the same conformation, significative structural differences exist between the native and the ΔN6β2-m proteins in solution with major differences located at the end moiety of strand V and subsequent loop with strand VI and at both the N- and C-termini of the proteins. On the contrary, an identical distribution of preferential proteolytic sites was observed in both proteins in the fibrillar state, which was nearly superimposible to that observed for the soluble form of ΔN6β2-m. These data revealed that synthetic fibrils essentially consists of an unaccessible core comprising residues 20-87 of the β2-m protein with exposed and flexible N- and C-terminal ends. Moreover, proteolytic cleavages observed in vitro at Lys 6 and Lys 19 reproduce specific cleavages that have to take place in vivo to generate the truncated forms of β2-m occurring in natural fibrils. On the basis of these results, a molecular mechanism for fibril formation has been propose

Exploring the mechanism of formation of native-like and precursor amyloid oligomers for the native acylphosphatase from Sulfolobus solfataricus

Over 40 human diseases are associated with the formation of well-defined proteinaceous fibrillar aggregates. Since the oligomers precursors to the fibrils are increasingly recognized to be the causative agents of such diseases, it is important to elucidate the mechanism of formation of these early species. The acylphosphatase from Sulfolobus solfataricus is an ideal system as it was found to form, under conditions in which it is initially native, two types of prefibrillar aggregates: (1) initial enzymatically active aggregates and (2) oligomers with characteristics reminiscent of amyloid protofibrils, with the latter originating from the structural reorganization of the initial assemblies. By studying a number of protein variants with a variety of biophysical techniques, we have identified the regions of the sequence and the driving forces that promote the first aggregation phase and show that the second phase consists in a cooperative conversion involving the entire globular fol

A new subfamily of fungal subtilases: structural and functional analysis of a Pleurotus ostreatus member

Pleurotus ostreatus produces several extracellular proteases which are believed to be involved in the regulation of the ligninolytic activities of this fungus. Recently, purification and characterization of the most abundant P. ostreatus extracellular protease (PoSl) have been reported. The sequence of the posl gene and of the corresponding cDNA has been determined, allowing the identification of its pre- and pro-sequences. A mature protein sequence has been verified by mass spectrometry mapping, the N-glycosylation sites have been identified and the glycosidic moieties characterized. Mature PoSl shows a cleaved peptide bond in the C-terminal region, which remains associated with the catalytic domain in a non-covalent complex. Reported results indicate that this enzyme is involved in the activation of other P. ostreatus secreted proteases, thus suggesting its leading role in cascade activation mechanisms. Analyses of the PoSl sequence by homology search resulted in the identification of a DNA sequence encoding a new protease, homologous to PoSl, in the Phanerochaete chrysosporium genome. A new subgroup of subtilisin-like proteases, belonging to the pyrolysin family, has been defined, which includes proteases from ascomycete and basidiomycete fungi

Evolution of protein bound Maillard reaction end-products and free Amadori compounds in low lactose milk in presence of fructosamine oxidase I

Thermal treatments and storage influence milk quality, particularly in low lactose milk as the higher concentration of reducing sugars can lead to the increased formation of the Maillard reaction products (MRPs). The control of the Amadori products (APs) formation is the key step to mitigate the Maillard reaction (MR) in milk. The use of fructosamine oxidases, (Faox) provided promising results. In this paper, the effects of Faox I were evaluated by monitoring the concentration of free and bound MRPs in low lactose milk during shelf life. Results showed that the enzyme reduced the formation of protein-bound MRPs down to 79% after six days at 37 °C. Faox I lowered the glycation of almost all the free amino acids resulting effective on basic and polar amino acids. Data here reported corroborate previous findings on the potentiality of Faox enzymes in controlling the early stage of the MR in foods

Treatment with lipid therapy to resuscitate a patient suffering from toxicity due to local anesthetics

Recently, although without a universal recognition, the use of lipid emulsions as a rescue therapy for the bupivacaine cardiac toxicity has been proposed. In this article we report a successful resuscitation of a patient after the injection of bupivacaine in emergency room and a commented review of the related literature. The patient is a 73 years old man that, after a subcutaneous injection of bupivacaine (0.5%, i.e. 0.5 mL/h), developed circulatory arrest. After the failure of the initial treatment based on the advanced life support protocol, we have successfully performed a therapy with lipid emulsion. The bupivacaine intravascular injection, together with its interaction with amitriptyline and carbamazepine, could lead to cardiac depression, severe arrhythmias, hypotension, and/or cardiac arrest. In the case of failure of traditional life support treatment, intravenous lipid emulsion proves to be the best therapy to treat bupivacaine systemic toxicity

Acute isolated sphenoid sinusitis in a 4-year-old child: a rare case with an atypical presentation

Acute, isolated, sphenoid sinusitis is unusual, especially in children. Its incidence is about 2.7% of all sinus infections and is even rarer in children under the age of six years. It is frequently misdiagnosed because of its atypical presentation and it can cause serious complications because of the sphenoid sinus\u27 anatomical relations with many intracranial structures. We report a case of a previously healthy 4 year old boy, whose sole symptom at presentation was drowsiness. Physical examination and initial laboratory investigations were normal. Diagnosis was made after computed tomography of the head revealed left sphenoiditis. Although under treatment, the child manifested meningism during the first day of hospitalization, which subsided the next day. He was treated with ceftriaxone plus clindamycin and had a good outcome, without complications or neurological sequelae

A strange case of Evans syndrome

Evans syndrome is a rare autoimmune disease presenting hemolytic anemia, thrombocytopenia and/or neutropenia. It may be associated with other autoimmune or lymphoproliferative diseases. It can have an extremely serious disease course and, in rare cases, this can even be life-threatening. First-line treatment consists of steroids and/or immunoglobulin. Further therapy with rituximab, vincristine, cyclophosphamide and other immunosuppressive drugs can be considered in unresponsive patients. We report a case of Evans syndrome in a 54-year old woman admitted to the Emergency Department (ED) for asthenia. Etiopathogenic, clinical, therapeutic and evolutive aspects are discussed. In contrast to many cases described in the literature, our patient had a satisfactory response to corticoids. We also discuss how to make a specific diagnosis, even in a suburban ED with limited resources, in order to admit patients to the appropriate hospital department and allow the correct therapy to be started as early as possible