187 research outputs found
Effects of hypercapnia on peripheral vascular reactivity in elderly patients with acute exacerbation of chronic obstructive pulmonary disease
No full textBlood acid-base imbalance has important effects on vascular reactivity, which can be related to nitric oxide (NO) concentration and increased during hypercapnia. Release of NO seems to be linked to H+ and CO2 concentration and to exacerbation of chronic obstructive pulmonary disease (COPD), a common medical condition in the elderly. Flow-mediated dilation (FMD), a valuable cardiovascular risk indicator, allows assessment of endothelial-dependent vasodilation, which is to a certain extent mediated by NO. We investigated the effects of hypercapnia and acid-base imbalance on endothelial-dependent vasodilation by measurement of FMD in 96 elderly patients with acute exacerbation of COPD. Patients underwent complete arterial blood gas analysis and FMD measurement before (phase 1) and after (phase 2) standard therapy for acute exacerbation of COPD and recovery. Significant differences between phase 1 and phase 2 were observed in the mean values of pH (7.38±0.03 versus 7.40±0.02, P<0.001), pO2 (59.6±4.9 mmHg versus 59.7±3.6 mmHg, P<0.001), pCO2 (59.3±8.63 mmHg versus 46.7±5.82 mmHg, P<0.001), FMD (10.0%±2.8% versus 8.28%±2.01%, P<0.001) and blood flow rate (1.5±0.3 m/s versus 1.5±0.3 m/s, P=0.001). FMD values were positively correlated with pCO2 values (r=0.294, P=0.004) at baseline. A significant correlation was also found between relative changes in FMD and pCO2 levels, passing from phase 1 to phase 2 (r = 0.23, P=0.023). Patients with higher baseline endothelium-dependent vasodilation as evaluated by FMD showed greater modification with regard to pCO2 changes (2.6±1.39 versus 1.59±1.4, P=0.012). In conclusion, endothelium-dependent vasodilation as evaluated by FMD was elevated during hypercapnia, and varied significantly according to pCO2 changes in patients with higher baseline levels, suggesting that vascular reactivity in acute COPD exacerbations in the elderly depends on integrity of the vascular endothelium. © 2014 de Matthaeis et al
Note preliminari sullo status tassonomico e la corologia italiana di Chalcolestes parvidens (st. nov.) (Odonata: Lestidae)
No full textSpeciation, genetic divergence and palaeogeography in the Hormogastridae
No full textSoil Biology and biochemistr
Temporal Population Genetics and COI Phylogeography of the Sandhopper Macarorchestia remyi (Schellenberg, 1950) (Amphipoda, Talitridae)
No full textIn this study we assessed levels of genetic divergence and variability in 208 individuals of the supralittoral sandhopper Macarorchestia remyi, a species strictly associated with rotted wood stranded on sand beaches, by analyzing sequence polymorphisms in a fragment of the mitochondrial DNA (mtDNA) gene coding cytochrome oxidase subunit I (COI). The geographical distribution and ecology of the species are poorly known. The study includes 1 Tyrrhenian and 2 Adriatic populations sampled along the Italian peninsula plus a single individual found on Corfu Is. (Greece). The Tyrrhenian population was sampled monthly for 1 yr. Genetic data revealed a deep phylogeographic break between the Tyrrhenian and Adriatic populations with no shared haplotypes. The single individual collected on Corfu Is. carried the most common haplotype found in the Tyrrhenian population. A mismatch analysis could not reject the hypothesis of a sudden demographic expansion in almost all but 2 monthly samples. When compared to previous genetic data centered on a variety of Mediterranean talitrids, our results place M. remyi among those species with profound intraspecific divergence (sandhoppers) and dissimilar from beachfleas, which generally display little population genetic structuring
Morphology and histology of the mouthparts and gut system of Macarorchestia remyi (Schellenberg, 1950) (Amphipoda, Talitridae
No full textMacarorchestia remyi lives in beached logs, where it makes its tunnels by eating the wood. Hence, this wood-feeding species has a peculiar diet compared with other Mediterranean talitrid amphipods. We carried out a morphological analysis of its mouthparts and a mainly histological investigation (transverse sections) of its gut regions (foregut, midgut and hindgut). The ectodermal foregut and hindgut regions are typically lined with cuticle, finely elaborated into various structures. Near the distal end of the oesophagus are the lateralia, provided with two rows of setae and several stout spines. The primary filter, including two parallel channels, is located ventrally in the first region of the foregut, while the secondary filter lies ventrally in the posterior foregut chamber, composed on each side of two longitudinal channels covered by densely arranged parallel setae. In the hindgut, the lining folded cuticle of the cylindrical epithelium shows unspecialized spines. In the endodermal midgut, the fine materials extracted from the upper foregut chambers through the filter systems are conveyed from the ventral channels to two pairs of ventrally located hepatopancreatic tubules; all these lobes, surrounding the midgut and partially the hindgut, are characterized by large vacuolated cells in their proximal regions. The midgut caeca includes the paired tubular pyloric caeca lateral to the secondary filter and a single caecum dorsal to the midgut. Two posterior caeca, originating in the distal part of the midgut, are located dorsolaterally and partially surround the hindgut. Finally, we observed layers of peritrophic membranes in the lumen of the midgut. In summary, the molar surface morphology appears to agree with the trend previously hypothesized for talitrid taxa with an increasing landward habitat and shifting toward a typical terrestrial diet. However, our data suggest that M. remyi, despite its particular feeding preference, shows no major differences in the main gut structures from other talitroid species. This relatively uniform morphology can be considered close to the ground pattern of the gammaridean amphipods, probably representing the early stage of Amphipoda evolutio
Molecular re-examination of the taxonomy of the Meligethes viridescens species-complex (Coleoptera: Nitidulidae).
No full textMolecular phylogeny of two lineages of Leuciscinae cyprinids (Telestes and Scardinius) from the peri-Mediterranean area based on cytochrome b data.
No full textWe examined phylogenetic relationships in two lineages of Leuciscinae cyprinid fishes based on the sequence data of the complete
mitochondrial DNA region coding for the cytochrome b gene (1140 bp). Telestes includes obligate riverine, moderately cold wateradapted
species whereas Scardinius comprises warm-adapted species living in lowland lakes and still waters of rivers and streams.
We also analysed selected representatives of Leuciscus and Phoxinellus because the taxonomic status of some species belonging to
these genera is dubious and they could be placed in the genus Telestes. The study includes 18 species, 43 populations, and 111
individuals from 9 of the 14 peri-Mediterranean ichthyogeographic districts. Clades recovered from the phylogenetic analyses do not
support previous taxonomic assumptions based on morphology. Telestes, Leuciscus, and Phoxinellus do not form monophyletic
assemblages; phylogenetic analyses suggest that L. polylepis, L. turskyi, P. croaticus, and P. metohiensis should be included in
Telestes. Similarly, populations of Scardinius erythrophthalmus do not cluster together and the endangered S. scardafa, endemic to
central Italy and surviving in a single locality, is nested within them. The radiations of Telestes and Scardinius occurred in different
time periods. A major diversification of Telestes is consistent with a sea dispersal during the freshwater Messinian ‘‘Lago Mare’’
phase of the Mediterranean Sea. Cladogenetic events within Scardinius are likely related to the extension and confluence of river
drainages in lowlands following multiple lowering of the sea level during the Quaternary glaciations
Pervietà interatriale nell'anziano: Quanto può esserne tardivo il riconoscimento?
No full textAtrial Septal Defect (ASD) is a common congenital heart disease where diagnosis is often performed in the late adulthood but the clinical presentation of ASD in the very elderly is uncommon. A case of a 95 year old male where the ASD diagnosis was delayed until present age is reported. This diagnostic delay suggests that very elderly people are often misdiagnosed for two main reasons: comorbidity and new symptoms. This matter that is a common bias at this age underestimation often excludes these patients from important diagnostic procedures
Specific distinction by allozimic data of sympatric species of anthophagous beetles (Coleoptera: Nitidulidae).
No full textPrediction of the Behavior of a CNG Tank Exposed to Flames
No full textThe increasing request of vehicles fuelled by Compressed Natural Gas (CNG) requires that the safety issues related to this kind of fuel should be analyzed more and more thoroughly. So far, the minimum requirement for a CNG tank is to set up a Pressure Relief Device (PRD) triggered by temperature. This work aims to develop a procedure able to perform thoroughly tank behavior analyses, in presence of fire, in order to reduce the number of expensive experimental tests and to improve the design criteria of tank safety devices. The procedure consists in the solution of the unsteady solid-fluid conjugate heat transfer problem, by means of numerical simulations, in order to evaluate the transient behavior of both the temperature field inside the solid walls of the tank and the thermo-fluid-dynamic field of the compressed gas inside it, when it is exposed to a heating source. Moreover, the melting process of the fusible plug, inside the PRD, is simulated. In order to validate this procedure, experimental tests have been carried out on a suitable test rig. Several heating conditions, even unlikely, but able to jeopardize safety, have been considered. The condition characterized by a flame located on the opposite side of the PRD has been recognized to be the most critical with respect to explosion risk. In this case, the relationship between time and tank pressure has been numerically evaluated. The fusible plug, inside the PRD, has been checked to be completely melted of the fusible plug before the pressure reaches the safety limit
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