1,720,982 research outputs found
Trafficking and intracellular processing of exogenous and endogenous proteins: VacA toxin from Helicobacter pylori as a tool
Full text linkINTRODUCTION
Eukaryotic cells are complex systems, which require a continuous flow of communication and material exchange between the intracellular and extracellular environments. The importance of a precise and fine-tuned cellular organization is demonstrated by the development of intracellular aggregates, such Particle-rich Cytoplasmic Structure (PaCS), as a result of altered trafficking or the failure of the degradation quality system to manage misfolded proteins. PaCSs were firstly identified in Helicobacter pylori (Hp) infected human superficial gastric epithelium and are present in a variety of cultured cell lines and ex vivo tissue. Inside PaCSs, it was found out the presence of Vacuolation toxin A (VacA), which has been recognized to be the key of the bacterium's ability to adapt in a hostile environment. VacA is a multifunctional toxin, with a similar structure and cleavage to the AB family of bacterial toxins. Intracellularly VacA can promote the formation of large vacuoles, arising from late endosome, but can alter also mitochondria functioning and intracellular calcium signaling, suggesting that the toxin could achieved the Endoplasmic Reticulum (ER).
AIM
The aims of this work are: to deeply characterize aggregates such as PaCSs, Lafora Bodies (LBs), Justanuclear Quality Control (JUNQ) and Insoluble Protein Deposit (IPOD) in order to investigate their nature and development; to elucidate the effect of trafficking inhibitor on VacA-induced vacuolization; to investigate VacA trafficking at different time.
RESULTS
Our results demonstrated that these aggregates are different inclusions, even if they share some similarities either structural or cytochemical. We observed that PaCSs and LBs are glycogen and laforin positive. A comprehensive analysis of JUNQ and IPOD showed that these aggregates have different ultrastructure from PaCSs and that they are mutually exclusive. Considering that inside PaCSs, VacA is accumulated together with polyubiquitin proteins and proteasome components, we evaluate if the toxin is ubiquitinated inside cells. Using histidine-tagged ubiquitin and metal affinity purification, we found out two bands, which might represent ubiquitinated VacA. We next analyzed the effect of eight different trafficking inhibitors, among which, EGA virtually abolish VacA-induced vacuolization. EGA effects was achieved also when vacuolization was already promoted, but it did not prevent toxin binding or internalization process. Binding-on-ice results support the idea that VacA can exploit the retrograde movement to reach ER. A preincubation time with EGA showed that the inhibitor can relocated the toxin to other organelles.
CONCLUSION
We demonstrated that PaCSs are unique aggregates and that VacA could be ubiquitinated inside cytoplasm. Our VacA ubiquitination and trafficking results supports the idea that the toxin could escape ER, reach the cytoplasm, ubiquitinated and later accumulated inside PaCSs. This approach could be a cell’s tool to prevent VacA cytotoxic effect and promote degradation, making vacuoles only an intermediate step of toxin trafficking. Moreover, we found out that EGA, a newly inhibitor with a powerful effect on several toxins, virtually abolished the toxin activity in all experiments. Its effects, associated to a low toxicity in mouse model, make it look like a potent inhibitor and interesting tool to develop therapeutic strategy against bacterial toxins
The interplay between movement and perception: how interaction can influence sensorimotor performance and neuromotor recovery
No full textMovement and perception interact continuously in daily activities. Motor output changes the
outside world and affect perceptual representations. Similarly, perception has consequences
on movement. Nevertheless, how movement and perception influence each other and share
information is still an open question.
Mappings from movement to perceptual outcome and vice versa change continuously
throughout life. For example, a cerebrovascular accident (stroke) elicits in the nervous
system a complex series of reorganization processes at various levels and with different
temporal scales. Functional recovery after a stroke seems to be mediated by use-dependent
reorganization of the preserved neural circuitry.
The goal of this thesis is to discuss how interaction with the environment can influence
the progress of both sensorimotor performance and neuromotor recovery. I investigate how
individuals develop an implicit knowledge of the ways motor outputs regularly correlate
with changes in sensory inputs, by interacting with the environment and experiencing the
perceptual consequences of self-generated movements. Further, I applied this paradigm to
model the exercise-based neurorehabilitation in stroke survivors, which aims at gradually
improving both perceptual and motor performance through repeated exercise.
The scientific findings of this thesis indicate that motor learning resolve visual perceptual
uncertainty and contributes to persistent changes in visual and somatosensory perception.
Moreover, computational neurorehabilitation may help to identify the underlying mechanisms
of both motor and perceptual recovery, and may lead to more personalized therapies
Lung cancer stage distribution from before COVID-19 through 18 months of the pandemic: the experience of a large-volume oncological referral centre
Full text linksponsorship: This work was partially supported by the Italian Ministry of Health with Ricerca Corrente and 5x1000 funds. (Italian Ministry of Health)status: Publishe
Self-operated stimuli improve subsequent visual motion integration
Full text linkEvidences of perceptual changes that accompany motor activity have been limited primarily to audition and somatosensation. Here we asked whether motor learning results in changes to visual motion perception. We designed a reaching task in which participants were trained to make movements along several directions, while the visual feedback was provided by an intrinsically ambiguous moving stimulus directly tied to hand motion. We find that training improves coherent motion perception and that changes in movement are correlated with perceptual changes. No perceptual changes are observed in passive training even when observers were provided with an explicit strategy to facilitate single motion perception. A Bayesian model suggests that movement training promotes the fine-tuning of the internal representation of stimulus geometry. These results emphasize the role of sensorimotor interaction in determining the persistent properties in space and time that define a percept
A review of exhaled breath: a key role in lung cancer diagnosis
No full textOne of the main causes of the high mortality rate in lung cancer is the late-stage tumor detection. Early diagnosis is therefore essential to increase the chances of obtaining an effective treatment quickly thus increasing the survival rate. Current screening techniques are based on imaging, with low-dose computed tomography (LDCT) as the pivotal approach. Even if LDCT has high accuracy, its invasiveness and high false positive rate limit its application to high-risk population screening. A noninvasive, cost-efficient, and easy-to-use test should instead be designed as an alternative. Exhaled breath contains thousands of volatile organic compounds (VOCs). Since ancient times, it has been understood that changes in the VOCs' mixture maybe directly related to the presence of a disease, and recent studies have quantified the change in the compounds' concentration. Analyzing exhaled breath to achieve lung cancer early diagnosis represents a non-invasive, low-cost, and user-friendly approach, thus being a promising candidate for high-risk lung cancer population screening. This review discusses technological solutions that have been proposed in the literature as tools to analyze exhaled breath for lung cancer diagnosis, together with factors that potentially affect the outcome of the analysis. Even if research on this topic started many years ago, and many different technological approaches have since been adopted, there is still no validated clinical application of this technique. Standard guidelines and protocols should be defined by the medical community in order to translate exhaled breath analysis to clinical practice
The role of endobronchial ultrasound transbronchial needle aspiration in patients candidate to pneumonectomy
Full text linkBackground: Lung cancer remains the leading cause of cancer, both in incidence and mortality. Surgery is the mainstay in the treatment of lung cancer and for locally advanced disease the removal of the entire lung (pneumonectomy) may be required. Careful patient staging is pivotal to determine appropriate surgery feasibility, complete resection probability and to evaluate neoadjuvant treatment.
Methods: We retrospectively reviewed 230 patients undergoing pneumonectomy for non-small-cell lung cancer (NSCLC) treatment from 2012–2019 at our Institution. The main objective of the study was to evaluate the role of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in the management of this group of patients. The Ethics Committee approved data collection and analysis and waived the need for written consent.
Results: Eighty patients (60 males, 75%) with a median age of 70 (range, 24–92) years were included at the analysis. Mediastinal staging was performed to achieve the histological cell type and staging in 49 patients (61.3%), for mediastinal staging alone in 14 cases (17.5%), to evaluate endobronchial and lymph node involvement in 5 (6.3%) cases, 6 (7.5%) cases of cN3 suspicious investigation and in 6 patients (7.5%) for cell type diagnosis, staging and a panel of mutations assessment. One hundred and nine mediastinal stations were sampled during mediastinal staging procedures, with 136 lymph nodes sampled. The most frequent station analyzed was the subcarinal (48.6%), followed by the right lower paratracheal station (24.8%) or both of them (21.0%). Neoadjuvant treatment was indicated in 41 (51.3%) patients after mediastinal staging that confirmed the mediastinal lymph node involvement. Sensitivity, negative predicted value and diagnostic accuracy were respectively 86.7%, 94.4% and 95.9%. The surgical resection type included 68 standard pneumonectomies, 46 extended resections, 3 sleeve pneumonectomies and 10 extended sleeve pneumonectomies’ for pericardium, superior vena cava, atrium or diaphragm resection with bronchoplastic. A lymph node downstaging promoted by the neoadjuvant treatment was observed in 11 patients (26.8%). The follow-up of patients was possible in all cases, with a median survival of 21.8 months.
Conclusions: In patients with lung cancer that require major surgical procedures, mediastinal staging plays an essential role. EBUS-TBNA is a minimally invasive procedure able to characterize the disease in terms of cell type and a full molecular analysis guiding the best neoadjuvant treatment without altering the surgical field with no major complications
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Learning bio-inspired head-centric representations of 3D shapes in an active fixation setting
Full text linkWhen exploring the surrounding environment with the eyes, humans and primates need to interpret three-dimensional (3D) shapes in a fast and invariant way, exploiting a highly variant and gaze-dependent visual information. Since they have front-facing eyes, binocular disparity is a prominent cue for depth perception. Specifically, it serves as computational substrate for two ground mechanisms of binocular active vision: stereopsis and binocular coordination. To this aim, disparity information, which is expressed in a retinotopic reference frame, is combined along the visual cortical pathways with gaze information and transformed in a head-centric reference frame. Despite the importance of this mechanism, the underlying neural substrates still remain widely unknown. In this work, we investigate the capabilities of the human visual system to interpret the 3D scene exploiting disparity and gaze information. In a psychophysical experiment, human subjects were asked to judge the depth orientation of a planar surface either while fixating a target point or while freely exploring the surface. Moreover, we used the same stimuli to train a recurrent neural network to exploit the responses of a modelled population of cortical (V1) cells to interpret the 3D scene layout. The results for both human performance and from the model network show that integrating disparity information across gaze directions is crucial for a reliable and invariant interpretation of the 3D geometry of the scene
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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