393 research outputs found
Neuroimaging of ventriculomegaly in the fetal period.
No full textFetal cerebral ventriculomegaly (VM) is defined as an enlargement of the lateral ventricles of the developing fetal brain. It is diagnosed when the width of one or both lateral ventricles, measured at the level of the atrium, is ≥10 mm. VM is defined as mild when the atrial width is 10-15 mm and severe when >15 mm. VM is a non-specific sonographic sign which is common to various pathological conditions. It is frequently associated with neural and extraneural anomalies. The rate of associated malformations is higher (≥60%) in severe VM and lower (about 40%) in cases of mild VM. When an abnormality is associated with severe VM the incidence of aneuploidies is high (>15%); in isolated mild VM the mean value of aneuploidy is 2.7%. The rate of infections in severe VM is 10-20%, in mild forms 1-5%. Since the prognosis in cases of VM depends mainly on the associated anomalies, a careful examination of the fetus, particularly of the brain, is mandatory. Magnetic resonance imaging can be a useful diagnostic tool complementary to ultrasound in order to recognize subtle brain anomalies, such as neuronal migration and proliferation disorders
Assessing gene expression of the endocannabinoid system
No full textReal-time quantitative reverse transcription polymerase chain reaction (real-time qRT-PCR), a major development of PCR technology, is a powerful and sensitive gene analysis technique that revolutionized the field of measuring gene expression. Here, we describe in detail RNA extraction, reverse transcription (RT), and relative quantification of genes belonging to the endocannabinoid system in mouse, rat, or human samples
A NEW APPROACH TO ASSESS THE SUSCEPTIBILITY TO SHALLOW LANDSLIDES AT REGIONAL SCALE AS INFLUENCED BY BEDROCK GEO-MECHANICAL PROPERTIES
No full textDue to high velocity, high frequency and the lack of warning signs, shallow landslides represent a major hazardous factor in mountain regions. Moreover, increasing urbanisation and climate changes triggering intense rainfall events make shallow landslides a source of widespread risk. The interest of the scientific community in this process has grown in the last three decades with the aim to perform robust shallow landslide hazard assessment at regional scale.
Generally, these slope failures involve relatively small volumes of material sliding along with a planar shallow rupture surface. In the literature it is widely accepted that shallow landslides involve only slope deposit (or colluvium) and the sliding surface correspond to the discontinuity between bedrock and the overlying loose material. The fieldwork conducted in this thesis highlighted that often shallow landslides involve also the weathered and fractured portion of bedrock. In this framework, the implementation of shallow landslides susceptibility modelling should take into account the engineering geological properties of slope deposits, as well as of the underlying bedrock. In this thesis a fieldwork-based method is proposed to acquire, process and spatialize engineering geological properties of slope deposits and bedrock. The aims of this thesis were to compile a new multi-temporal shallow landslide inventory, characterize the engineering geological properties of slope deposits and bedrock, implement and compare shallow landslide susceptibility modelling by means a physically-based and a data-driven methods and explore the role of bedrock in shallow slope failures. The study area corresponds to a 242 km2 portion of the Garfagnana basin (Northern Apennines), a mountainous region where the elevation ranges between 150 and 2000 m a.s.l. characterized by an incised and rugged morphology with steep slopes (average 28° degrees) and a mean annual rainfall between 1500 and 2500 mm/year. From a geological point of view, the Garfagnana basin is a narrow intra-mountainous valley, interposed betweeen the Alpi Apuane metamorphic complex to the east and the sedimentary northern Apennine’s ridge to the west.
The fieldwork and laboratory tasks carried out to map engineering geology characters of slope deposits consisted on a set of hundreds of field sampling points, with the acquisition of depth to the bedrock, geotechnical horizons, unit weight, as well as soil samples for lab analysis. The distribution of points was chosen by observing that engineering geology properties of slope deposits depend on both bedrock lithology and morphometric conditions. In order to obtain the map distribution of engineering geology parameters, we implemented a spatial analysis by clustering morphometric variables stratified as a function of bedrock lithological units. In order to investigate the engineering geology characteristics of the bedrock, a field survey aimed to classify rock masses was conducted. For each survey site, 200-400 Schmidt hammer rebound measures, bedding and joint data, GSI (Geological Strenght Index) and samples for laboratory analyses (unit weight and slake durability test) were collected. The field data were processed and spatially analyzed by means uni-variate and multi-variate cluster analysis in order to delineate domains with different bedrock geo-mechanical properties. The shallow landslide susceptibility analysis was performed using both data-driven, Information Value, and physically-based, a modified version of SHALSTAB model (PROBSS), methods.
The numerical modelling faced three issues: a) the comparison of PROBSS and Information value (IV) in the prediction of shallow landslides involving SD; b) the training and cross-validation of IV models using shallow landslides involving bedrock or not; c) implementation of a physically-based model to predict involving bedrock shallow landslides. First of all, the results highlight that the field-based methods proposed here to evaluate engineering geological properties of slope deposits and bedrock are adequate for the implementation of regionalised physically-based susceptibility models.
The comparison between PROBSS and IV highlights that the simplification of shallow landslides adopted by the infinite slope model which do not take into account the occurrence of a sliding surface located below the slope deposits / bedrock discontinuity, may affect the performance of physically-based susceptibility models. The accuracy of IV model is slightly better that PROBSS model. Having implemented two data-driven susceptibility models using two different training datasets highlighted the different characteristics that slope deposits and bedrock involving shallow landslides have, suggesting and demonstrating that the latter occur in conditions that the physically based model cannot predict. By placing the slip surface below the discontinuity between slope deposits and bedrock and providing shear strength parameters compatible with a weathered and fractured rock material, satisfactory accuracy result was obtained with PROBSS model
Chronic and acute effects of 3,4-methylenedioxy-N-methylamphetamine ('Ecstasy') administration on the dynorphinergic system in the rat brain
No full textThe prodynorphin system is implicated in the neurochemical mechanism of psychostimulants. Exposure to different drugs of abuse can induce neuroadaptations in the brain and affect opioid gene expression. The present study aims to examine the possibility of a common neurobiological substrate in drug addiction processes. We studied the effects of single and repeated 3,4-methylenedioxy-N-methylamphetamine ('Ecstasy') on the gene expression of the opioid precursor prodynorphin, and on the levels of peptide dynorphin A in the rat brain. Acute (8 mg/kg, intraperitoneally) 3,4-methylenedioxy-N-methylamphetamine markedly raised, two hours later, prodynorphin mRNA levels in the prefrontal cortex, and in the caudate putamen, whereas it decreased gene expression in the ventral tegmental area. Chronic (8 mg/kg, intraperitoneally, twice a day for 7 days) 3,4-methylenedioxy-N-methylamphetamine increased prodynorphin mRNA in the nucleus accumbens, hypothalamus and caudate putamen and decreased it in the ventral tegmental area. Dynorphin A levels increased after chronic treatment in the ventral tegmental area and decreased after acute treatment in the nucleus accumbens, prefrontal cortex and hypothalamus. These findings confirm the role of the dynorphinergic system in mediating the effects of drugs of abuse, such as 3,4-methylenedioxy-N-methylamphetamine, in various regions of the rat brain, which may be important sites for the opioidergic mechanisms activated by addictive drugs
Weathering Effects on Engineering Geological Properties of Trachydacitic Volcanic Rocks from the Monte Amiata (Southern Tuscany, Italy)
No full textVariability in lithology and weathering degree affects physical and mechanical properties
of rocks. In this study, we investigated the relationships between weathering degree and engineering
geological properties of trachydacitic volcanic rocks from Monte Amiata (central Italy) by coupling
field and laboratory analyses. We collected in situ Schmidt hammer tests in the field. We evaluated
weathering quantifying the percentage of secondary minerals through thermal analysis in the
laboratory. We also determined dry density (rd), specific gravity of solids (Gs), porosity (n) and
two-dimensional (2D) porosity as resulted from scanning electron microscopy investigations. The
results of our study indicate a negative linear correlation between Schmidt hammer rebound values
and secondary mineral percentage. This correlation provides a tool to quantitatively estimate the
deterioration of rock uniaxial compressive strength (UCS) as weathering increases. Moreover, thermal
analysis turned out to be a quantitative and reproducible method to evaluate weathering degree of
magmatic rocks
The k-opioid receptor agonist U-69593 prevents cocaine-induced DARPP-32 phosphorylation at Thr34 in the rat brain
No full textDARPP-32 (dopamine- and cAMP-regulated phosphoprotein) is a potent endogenous inhibitor of protein phosphatase-1, which plays an important role in dopaminergic transmission. A large body of evidence supports the key role of DARPP-32-dependent signalling in mediating the actions of multiple drugs of abuse, including cocaine, which, when acutely administered, increases the Thr34 phosphorylation of DARPP-32 in the striatal and cortical areas. In this study, we have examined the contribution of the kappa-opioid system to the regulation of DARPP-32 phosphorylation at Thr34, following acute cocaine administration, in selected rat brain areas.
Results showed that a single injection of cocaine induces a significant increase in DARPP-32 phosphorylation at Thr34 in the hippocampus, caudate putamen and prefrontal cortex. In addition, pretreatment with the kappa opioid receptor agonist U-69593 prevented cocaine effects in all the investigated areas. These data could be considered consistent with the ability of kappa opioid agonists to attenuate many behavioural effects of cocaine, and support the hypothesis of the potential usefulness of these drugs as functional antagonists of cocaine
Epigenetic mechanisms and endocannabinoid signalling.
No full textThe endocannabinoid system, composed of endogenous lipids, their target receptors and metabolic enzymes, has been implicated in multiple biological functions in health and disease, both in the central nervous system and in peripheral organs. Despite the exponential growth of experimental evidence on the key role of endocannabinoid signalling in basic cellular processes, and on its potential exploitation for therapeutic interventions, much remains to be clarified about the respective regulatory mechanisms. Epigenetics refers to a set of post-translational modifications that regulate gene expression without causing variation in DNA sequence, endowed with a major impact on signal transduction pathways. The epigenetic machinery includes DNA methylation, histone modifications, nucleosome positioning and non-coding RNAs. Due to the reversibility of epigenetic changes, an emerging field of interest is the possibility of an 'epigenetic therapy' that could possibly be applied also to endocannabinoids. Here, we review current knowledge of epigenetic regulation of endocannabinoid system components under both physiological and pathological conditions, as well as the epigenetic changes induced by endocannabinoid signalling
DAT1 Gene methylation as an epigenetic biomarker in attention deficit hyperactivity disorder. A commentary
No full textTranscriptional regulation of the endocannabinoid system in a rat model of binge-eating behavior reveals a selective modulation of the hypothalamic fatty acid amide hydrolase gene.
No full textOBJECTIVE:
Binge-eating episodes are recurrent and are defining features of several eating disorders. Thus binge-eating episodes might influence eating disorder development of which exact underlying mechanisms are still largely unknown.
METHODS:
Here we focused on the transcriptional regulation of the endocannabinoid system, a potent regulator of feeding behavior, in relevant rat brain regions, using a rat model in which a history of intermittent food restriction and a frustration stress induce binge-like palatable food consumption.
RESULTS:
We observed a selective down-regulation of fatty acid amide hydrolase (faah) gene expression in the hypothalamus of rats showing the binge-eating behavior with a consistent reduction in histone 3 acetylation at lysine 4 of the gene promoter. No relevant changes were detected for any other endocannabinoid system components in any brain regions under study, as well as for the other epigenetic mechanisms investigated (DNA methylation and histone 3 lysine 27 methylation) at the faah gene promoter.
DISCUSSION:
Our findings suggest that faah transcriptional regulation is a potential biomarker of binge-eating episodes, with a relevant role in the homeostatic regulation of food intake
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