137 research outputs found
Validation study of WindTrax reverse dispersion model coupled with a sensitivity analysis of model-specific settings
In last years, atmospheric dispersion models have reached considerable popularity in environmental research field. In this regard, given the difficulties associated to the estimation of emission rate for some kind of sources, and due to the importance of this parameter for the reliability of the results, Backward dispersion models may represent promising tools. In particular, by knowing a measured downwind concentration in ambient air, they provide a numerical value for the emission rate. This paper discusses a critical validation of the WindTrax Backward model: the investigation does not only deal with the strict reliability of the model but also assesses under which conditions (i.e. stability class, number, and location of the sensors) the model shows the greatest accuracy. For this purpose, WindTrax results have been compared to observed values obtained from available experimental datasets. In addition, a sensitivity study regarding model-specific parameters required by WindTrax to replicate the physics and the random nature of atmospheric dispersion processes is discussed. This is a crucial point, since, for these settings, indications on the numerical values to be adopted are not available. From this study, it turns out that the investigated model specific settings do not lead to a significant output variation. Concerning the validation study, a general tendency of the model to predict the observed values with a good level of accuracy has been observed, especially under neutral atmospheric conditions. In addition, it seems that WindTrax underestimates the emission rate during unstable stratification and overestimates during stable con-ditions. Finally, by the definition of alternative scenarios, in which only a portion of the concentration sensors was considered, WindTrax performance appears better than acceptable even with a small number of concen-tration sensors, as long as the positioning is in the middle of the plume and not in the strict vicinity of the source
Liver Transplantation in Patients with Alcohol-Associated Liver Disease: Current Strategies and Future Perspectives
Patients with alcohol-related liver disease (ALD) who receive a liver transplant (LT) reach a one-year post LT survival of 80–85%. The rule of abstinence from alcohol for 6 months before transplantation has been applied widely, but few data support the use of this rule as the only criterion for selecting LT candidates. Today, many liver transplant centers try to balance the duration of abstinence against the risk of death associated with the severity of ALD. Since 2011, an increasing number of papers suggests that transplantation without a specific period of abstinence (early LT) among patients with severe and nonmedical-therapy responder alcoholic hepatitis is an effective therapeutic strategy. Further data are needed to better define the selection of patients with ALD who have been abstinent for less than 6 months as suitable LT candidates and to improve the treatment of alcohol use disorder in those patients who have received a LT reducing the risk of alcohol abuse recurrence
Self-physical and emotional perception in water polo for drop out
To try to have a global view of the phenomenon of abandonment, we must ask ourselves what are the main reasons and psychological dynamics that convince a child to start any sport activity. In Italy, unfortunately, it is not always the children who choose the physical and sporting activity to practice, but often it is the parents and this is a serious mistake and could be one of the causes of abandonment at an early age. Sport activity in adolescence, especially practiced at a competitive level, is grafted on ground rich in interpersonal reversals and existential problems, going to affect intrapsychic dynamism and acting on the ability to control the ego and the unconscious dynamics that in this period undergo massive readjustments. The aim of the study is to study, in different groups of athletes (7-12 years, 13-17 years, 17-30 years) of water polo, how they deal emotionally and physically with the physical and emotional workloads and especially if you find physical and mental well-being. The method of the study is qualitative/quantitative and the administration of 10 questions: 5 to identify the physical self-perception and 5 for the emotional one, is done anonymously. The data shows that the self-perception for physical performance is on average positive and the self-perception for motivation performance is on average negative. This data is significant for the perceptive state of the athletes to whom it is necessary to refer in order to face the problem realistically. Given the data and their significance, the study must be deepened with a more significant and detailed sample of data
Acute kidney injury and chronic kidney disease after liver transplant: A retrospective observational study.
BACKGROUND AND RATIONALE Chronic kidney disease remains an important risk factor for morbidity and mortality among LT recipients, but its exact incidence and risk factors are still unclear. MATERIAL AND METHODS We carried out a retrospective cohort study of consecutive adults who underwent liver transplant (January 2009-December 2018) and were followed (at least 6 months) at our institution. CKD was defined following the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guidelines. Long-term kidney function was classified into 4 groups: no CKD (eGFR, ≥60mL/min/1.73m2), mild CKD (eGFR, 30-59mL/min/1.73m2), severe CKD (eGFR, 15-29mL/min/1.73m2), and end-stage renal disease (ESRD). RESULTS We enrolled 410 patients followed for 53.2±32.6 months. 39 had CKD at baseline, and 95 developed de novo CKD over the observation period. There were 184 (44.9%) anti-HCV positive, 47 (11.5%) HBsAg positive, and 33 (8.1%) HBV/HDV positive recipients. Recipient risk factors for baseline CKD were advanced age (P=0.044), raised levels of serum uric acid (P<0.0001), and insulin dependent DM (P=0.0034). Early post-transplant AKI was common (n=95); logistic regression analysis found that baseline serum creatinine was an independent predictor of early post-LT AKI (P=0.0154). According to our Cox proportional hazards model, recipient risk factors for de novo CKD included aging (P<0.0001), early post-transplant AKI (P=0.007), and baseline serum creatinine (P=0.0002). At the end of follow-up, there were 116 LT recipients with CKD - 109 (93.9%) and 7 (6.1%) had stage 3 and advanced CKD, respectively. Only two of them are undergoing long-term dialysis. CONCLUSION The incidence of CKD was high in our cohort of LT recipients, but only a slight decline in kidney function over time was recorded. Prevention of post-transplant AKI will improve kidney function in the long run. We need more studies to analyze the function of kidneys among LT recipients over extended follow-ups and their impact on mortality
Mutations of the Mitochondrial-tRNA Modifier MTO1 Cause Hypertrophic Cardiomyopathy and Lactic Acidosis
Dysfunction of mitochondrial respiration is an increasingly recognized cause of isolated hypertrophic cardiomyopathy. To gain insight into the genetic origin of this condition, we used next-generation exome sequencing to identify mutations in MTO1, which encodes mitochondrial translation optimization 1. Two affected siblings carried a maternal c.1858dup (p.Arg620Lysfs∗8) frameshift and a paternal c.1282G>A (p.Ala428Thr) missense mutation. A third unrelated individual was homozygous for the latter change. In both humans and yeast, MTO1 increases the accuracy and efficiency of mtDNA translation by catalyzing the 5-carboxymethylaminomethylation of the wobble uridine base in three mitochondrial tRNAs (mt-tRNAs). Accordingly, mutant muscle and fibroblasts showed variably combined reduction in mtDNA-dependent respiratory chain activities. Reduced respiration in mutant cells was corrected by expressing a wild-type MTO1 cDNA. Conversely, defective respiration of a yeast mto1Δ strain failed to be corrected by an Mto1Pro622∗ variant, equivalent to human MTO1Arg620Lysfs∗8, whereas incomplete correction was achieved by an Mto1Ala431Thr variant, corresponding to human MTO1Ala428Thr. The respiratory yeast phenotype was dramatically worsened in stress conditions and in the presence of a paromomycin-resistant (PR) mitochondrial rRNA mutation. Lastly, in vivo mtDNA translation was impaired in the mutant yeast strains
Variants in ATP5F1B are associated with dominantly inherited dystonia
Nasca et al. identify a new candidate gene for dystonia, ATP5F1B, encoding a subunit of the mitochondrial ATP synthase (complex V). Likely pathogenic variants in ATP5F1B were associated with early-onset isolated dystonia in two independent families, both with an autosomal dominant mode of inheritance and incomplete penetrance. ATP5F1B is a subunit of the mitochondrial ATP synthase or complex V of the mitochondrial respiratory chain. Pathogenic variants in nuclear genes encoding assembly factors or structural subunits are associated with complex V deficiency, typically characterized by autosomal recessive inheritance and multisystem phenotypes. Movement disorders have been described in a subset of cases carrying autosomal dominant variants in structural subunits genes ATP5F1A and ATP5MC3. Here, we report the identification of two different ATP5F1B missense variants (c.1000A>C;p.Thr334Pro and c.1445T>C;p.Val482Ala) segregating with early-onset isolated dystonia in two families, both with autosomal dominant mode of inheritance and incomplete penetrance. Functional studies in mutant fibroblasts revealed no decrease of ATP5F1B protein amount but severe reduction of complex V activity and impaired mitochondrial membrane potential, suggesting a dominant-negative effect. In conclusion, our study describes a new candidate gene associated with isolated dystonia and confirms that heterozygous variants in genes encoding subunits of the mitochondrial ATP synthase may cause autosomal dominant isolated dystonia with incomplete penetrance, likely through a dominant-negative mechanism
Novel NDUFA12 variants are associated with isolated complex I defect and variable clinical manifestation
Isolated biochemical deficiency of mitochondrial complex I is the most frequent signature among mitochondrial diseases and is associated with a wide variety of clinical symptoms. Leigh syndrome represents the most frequent neuroradiological finding in patients with complex I defect and more than 80 monogenic causes have been involved in the disease. In this report, we describe seven patients from four unrelated families harboring novel NDUFA12 variants, with six of them presenting with Leigh syndrome. Molecular genetic characterization was performed using next-generation sequencing combined with the Sanger method. Biochemical and protein studies were achieved by enzymatic activities, blue native gel electrophoresis, and western blot analysis. All patients displayed novel homozygous mutations in the NDUFA12 gene, leading to the virtual absence of the corresponding protein. Surprisingly, despite the fact that in none of the analyzed patients, NDUFA12 protein was detected, they present a different onset and clinical course of the disease. Our report expands the array of genetic alterations in NDUFA12 and underlines phenotype variability associated with NDUFA12 defect
New genes and pathomechanisms in mitochondrial disorders unraveled by NGS technologies.
Next Generation Sequencing (NGS) technologies are revolutionizing the diagnostic screening for rare disease entities, including primary mitochondrial disorders, particularly those caused by nuclear gene defects. NGS approaches are able to identify the causative gene defects in small families and even single individuals, unsuitable for investigation by traditional linkage analysis. These technologies are contributing to fill the gap between mitochondrial disease cases defined on the basis of clinical, neuroimaging and biochemical readouts, which still outnumber by approximately 50% the cases for which a molecular-genetic diagnosis is attained. We have been using a combined, two-step strategy, based on targeted genes panel as a first NGS screening, followed by whole exome sequencing (WES) in still unsolved cases, to analyze a large cohort of subjects, that failed to show mutations in mtDNA and in ad hoc sets of specific nuclear genes, sequenced by the Sanger's method. Not only this approach has allowed us to reach molecular diagnosis in a significant fraction (20%) of these difficult cases, but it has also revealed unexpected and conceptually new findings. These include the possibility of marked variable penetrance of recessive mutations, the identification of large-scale DNA rearrangements, which explain spuriously heterozygous cases, and the association of mutations in known genes with unusual, previously unreported clinical phenotypes. Importantly, WES on selected cases has unraveled the presence of pathogenic mutations in genes encoding non-mitochondrial proteins (e.g. the transcription factor E4F1), an observation that further expands the intricate genetics of mitochondrial disease and suggests a new area of investigation in mitochondrial medicine. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi
Ropinirole and pramipexole promote structural plasticity in human iPSC- derived dopaminergic neurons via BDNF and mTOR signaling
The antiparkinsonian ropinirole and pramipexole are D3 receptor- (D3R-) preferring dopaminergic (DA) agonists used as
adjunctive therapeutics for the treatment resistant depression (TRD). While the exact antidepressant mechanism of action
remains uncertain, a role for D3R in the restoration of impaired neuroplasticity occurring in TRD has been proposed. Since
D3R agonists are highly expressed on DA neurons in humans, we studied the effect of ropinirole and pramipexole on structural
plasticity using a translational model of human-inducible pluripotent stem cells (hiPSCs). Two hiPSC clones from healthy
donors were differentiated into midbrain DA neurons. Ropinirole and pramipexole produced dose-dependent increases of
dendritic arborization and soma size after 3 days of culture, effects antagonized by the selective D3R antagonists
SB277011-A and S33084 and by the mTOR pathway kinase inhibitors LY294002 and rapamycin. All treatments were also
effective in attenuating the D3R-dependent increase of p70S6-kinase phosphorylation. Immunoneutralisation of BDNF,
inhibition of TrkB receptors, and blockade of MEK-ERK signaling likewise prevented ropinirole-induced structural plasticity,
suggesting a critical interaction between BDNF and D3R signaling pathways. The highly similar profiles of data acquired
with DA neurons derived from two hiPSC clones underpin their reliability for characterization of pharmacological agents
acting via dopaminergic mechanisms
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