415 research outputs found
Integrating phenotypes and endotypes in chronic rhinosinusitis: a combined clinical and experimental approach.
Chronic rhinosinusitis (CRS) represents a hot and debated topic in rhinology because of its high prevalence, heterogeneity of clinical manifestations and unpredictability of disease course. The quite recent dichotomic classification of CRS with and without nasal polyps has proved to be too simplistic to fully explain CRS manifestations and the underlying pathogenetic mechanisms. Being either the same phenotype expression of substantially different pathogenic mechanisms or different phenotypes the expression of the same mechanism, a one-size-fit-all therapeutic approach turned out to be insufficient in a non-negligible proportion of patients.
Moreover, considering the attempt of giving a classification cut at a biomolecular level, a diagnostic and prognostic approach exclusively limited to subjective and objective clinical parameters is inevitably failing in many ways. However, to date no other more effective markers are available to monitor the trend of the disease.
The fact of dealing with an apparently very frequent pathology responsible for a strong discomfort on the QoL and a substantial economic impact requires a diagnostic and therapeutic appropriateness for an adequate allocation of resources within the standards of precision medicine. The development of systems for a uniform archiving and sharing of the experiences of each rhinological center would enhance the efforts of the scientific community in defining integrated and targeted care pathways.
The present thesis reports the results and the practical implications of three different experimental studies about the implementation of data storage and sharing systems, methods of analysis of therapeutic outcomes and inflammatory biomarkers in CRS
Impaired coronary blood flow at higher heart rates during atrial fibrillation: investigation via multiscale modelling
Background. Different mechanisms have been proposed to relate atrial
fibrillation (AF) and coronary flow impairment, even in absence of relevant
coronary artery disease (CAD). However, the underlying hemodynamics remains
unclear. Aim of the present work is to computationally explore whether and to
what extent ventricular rate during AF affects the coronary perfusion.
Methods. AF is simulated at different ventricular rates (50, 70, 90, 110, 130
bpm) through a 0D-1D multiscale validated model, which combines the left
heart-arterial tree together with the coronary circulation. Artificially-built
RR stochastic extraction mimics the \emph{in vivo} beating features. All the
hemodynamic parameters computed are based on the left anterior descending (LAD)
artery and account for the waveform, amplitude and perfusion of the coronary
blood flow.
Results. Alterations of the coronary hemodynamics are found to be associated
either to the heart rate increase, which strongly modifies waveform and
amplitude of the LAD flow rate, and to the beat-to-beat variability. The latter
is overall amplified in the coronary circulation as HR grows, even though the
input RR variability is kept constant at all HRs.
Conclusions. Higher ventricular rate during AF exerts an overall coronary
blood flow impairment and imbalance of the myocardial oxygen supply-demand
ratio. The combined increase of heart rate and higher AF-induced hemodynamic
variability lead to a coronary perfusion impairment exceeding 90-110 bpm in AF.
Moreover, it is found that coronary perfusion pressure (CPP) is no longer a
good measure of the myocardial perfusion for HR higher than 90 bpm.Comment: 8 pages, 5 figures, 3 table
Cardiovascular deconditioning during long-term spaceflight through multiscale modeling
Human spaceflight has been fascinating man for centuries, representing the
intangible need to explore the unknown, challenge new frontiers, advance
technology and push scientific boundaries further. A key area of importance is
cardiovascular deconditioning, that is, the collection of hemodynamic changes -
from blood volume shift and reduction to altered cardiac function - induced by
sustained presence in microgravity. A thorough grasp of the 0G adjustment point
per se is important from a physiological viewpoint and fundamental for
astronauts' safety and physical capability on long spaceflights. However,
hemodynamic details of cardiovascular deconditioning are incomplete,
inconsistent and poorly measured to date; thus a computational approach can be
quite valuable. We present a validated 1D-0D multiscale model to study the
cardiovascular response to long-term 0G spaceflight in comparison to the 1G
supine reference condition. Cardiac work, oxygen consumption and contractility
indexes, as well as central mean and pulse pressures were reduced, augmenting
the cardiac deconditioning scenario. Exercise tolerance of a spaceflight
traveler was found to be comparable to an untrained person with a sedentary
lifestyle. At the capillary-venous level significant waveform alterations were
observed which can modify the regular perfusion and average nutrient supply at
the cellular level. The present study suggests special attention should be paid
to future long spaceflights which demand prompt physical capacity at the time
of restoration of partial gravity (e.g., Moon/Mars landing). Since spaceflight
deconditioning has features similar to accelerated aging understanding
deconditioning mechanisms in microgravity are also relevant to the
understanding of aging physiology on Earth.Comment: 14 pages, 5 tables, 5 figure
Nitrogen and energy partitioning in two genetic groups of pigs fed low-protein diets at 130 kg body weight
The aim was to evaluate the effect of low-protein (LP) or low-amino acid diets on digestibility, energy and nitrogen (N) utilisation in 2 genetic groups (GG) of pigs (129±11 kg BW). Duroc×Large White (A) pigs were chosen to represent a traditional GG for ham production, and Danbred Duroc (D) pigs to represent a GG with fast growing rate and high carcass lean yield. Dietary treatments: a conventional diet (CONV) containing 13.2% CP, and two LP diets, one with LP (10.4%) and low essential AA (LP1), the second with LP (9.7%) and high essential AA (LP2). Compared to CONV, LP2 had the same essential AA content per unit feed, while LP1 the same essential AA content per unit CP. Feed was restricted (DMI=6.8% BW0.75). Four consecutive digestibility/balances periods were conducted with 24 barrows, 12 A and 12 D. Metabolic cages and respiration chambers were used. No significant difference between diets was registered for digestibility. Nitrogen excreted: 41.3, 33.4 and 29.0 g/d (P=0.009), for CONV, LP1 and LP2 diets, respectively. Nitrogen retention was similar between the diets. Heat production (HP) was the lowest for LP diets. There was a tendency (P=0.079) for a lower energy digestibility in D group. The D pigs also had a higher HP and hence a lower retained energy in comparison with the A pigs. In conclusion: it is possible to reduce N excretion using very LP diets and LP-low AA diets; Danbred GG have a higher heat production and a lower energy retention than A pigs
Analysis of natural killer–cell function in familial hemophagocytic lymphohistiocytosis (FHL): defective CD107a surface expression heralds Munc13-4 defect and discriminates between genetic subtypes of the disease
Abstract
Natural killer (NK) cells from patients with familial hemophagocytic lymphohistiocytosis because of PRF1 (FHL2, n = 5) or MUNC13-4 (FHL3, n = 8) mutations were cultured in IL-2 prior to their use in various functional assays. Here, we report on the surface CD107a expression as a novel rapid tool for identification of patients with Munc13-4 defect. On target interaction and degranulation, FHL3 NK cells displayed low levels of surface CD107a staining, in contrast to healthy control subjects or perforin-deficient NK cells. B-EBV cell lines and dendritic cell targets reveal the FHL3 NK-cell defect, whereas highly susceptible tumor targets were partially lysed by FHL3 NK cells expressing only trace amounts of Munc13-4 protein. Perforin-deficient NK cells were completely devoid of any ability to lyse target cells. Cytokine production induced by mAb-crosslinking of triggering receptors was comparable in patients and healthy control subjects. However, when cytokine production was induced by coculture with 721.221 B-EBV cells, FHL NK cells resulted in high producers, whereas control cells were almost ineffective. This could reflect survival versus elimination of B-EBV cells (ie, the source of NK-cell stimulation) in patients versus healthy control subjects, thus mimicking the pathophysiologic scenario of FHL
Oncogenic Alternative Splicing Switches: Role in Cancer Progression and Prospects for Therapy
Alterations in the abundance or activities of alternative splicing regulators generate alternatively spliced variants that contribute to multiple aspects of tumor establishment, progression and resistance to therapeutic treatments. Notably, many cancer-associated genes are regulated through alternative splicing suggesting a significant role of this post-transcriptional regulatory mechanism in the production of oncogenes and tumor suppressors. Thus, the study of alternative splicing in cancer might provide a better understanding of the malignant transformation and identify novel pathways that are uniquely relevant to tumorigenesis. Understanding the molecular underpinnings of cancer-associated alternative splicing isoforms will not only help to explain many fundamental hallmarks of cancer, but will also offer unprecedented opportunities to improve the efficacy of anti-cancer treatments
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