1,099 research outputs found
The clinical and biological impact of viral respiratory infections on the human airway: focus on rhinovirus
No full textInterferon-gamma downregulates the rhinovirus induced expression of intercellular adhesion molecule-1 (ICAM-1) on human airway epithelial cells
No full textHuman rhinoviruses (HRV) are a major cause of upper respiratory tract infections in man, and can exacerbate existing pulmonary disease. The major group of HRV attach to ICAM-1, which is expressed on nasal and bronchial epithelial cells. To study the influence of biological mediators on ICAM-1 expression, and consequently HRV attachment and infection, we compared the effects of various cytokines, alone and in combination, on ICAM-1 expression by an uninfected and HRV-infected bronchial epithelial cell line H292. Cytokines known to be released soon after viral infection, such as tumour necrosis factor-alpha (TNF-alpha), IL-1beta and the chemokine IL-8 increase ICAM-1 expression on uninfected cells. Epithelial cells infected with live HRV-14 displayed marked up-regulation of ICAM-1 compared with baseline. TNF-alpha further enhanced the HRV-induced increase in ICAM-1 expression on epithelial cells, peaking at day 4 after infection, whilst IL-8 exhibited a steady increase in ICAM-1 expression over 14 days. In contrast, IFN-gamma, a known Th1 antiviral lymphokine, whilst increasing the level of ICAM-1 on uninfected cells, induced a significant persistent down-regulation of ICAM-1 expression on HRV-infected epithelial cells. With combinations of TNF-alpha and IFN-gamma, ICAM-1 expression on HRV-infected cells was reduced to basal levels. The effects of IFN-gamma were paralleled by a reduction in viral titres. Our in vitro model has provided useful insights into the early pathogenic events of HRV infection at the level of the host cell-virus interaction. Our data confirm that biological mediators play a crucial role in the pathogenesis as well as the course of HRV infection which is modulated by the types, and time kinetics of inflammatory cytokines in the immediate microenvironment
Peripheral anergy and local immune hyperactivation in sarcoidosis: A paradox or birds of a feather
No full textLandmark Recognition and Mental Route Navigation Disorders in Patients with Imagery Neglect and Perceptual Neglect
No full textThe complex relationship between perceptual neglect and imagery neglect is still not completely understand because, at least in part, these disorders depend on are associated with, different neural systems and can be dissociated even in the same patient (Beschin, Basso, & Della Sala, 2000). Recent studies show that imagery neglect affects specific mechanisms underlying human orientation. In particular, it impairs the ability to manipulate mental representations of the environment and thus prevents the use of previous navigational experience (see for instance Guariglia et al., 2005; Piccardi, 2009; Guariglia & Piccardi, 2010). In this study, we compared the route learning and delayed recall task performance of imagery neglect patients with pure perceptual neglect patients, patients with no neglect and healthy participants. They had to learn a circular pathway in an unexplored area of the hospital; it included 13 landmarks and five turning points (three on the right and two on the left). During the learning phase, the participants explored the pathway three times with the examiner, who pointed out the landmarks. At the end of this phase, the participants performed two different tasks: a) Landmark Recognition Task and b) Navigational Questions. The first task included 26 pictures of landmarks (13 target pictures and 13 fillers) located along the pathway that the participants had to recognize. Fillers were the same type of stimuli as the target, but with different characteristics (e.g., two different doors). The second, delayed recall task consisted of 30 questions investigating the participants' ability to recall a learned pathway and the landmarks encountered along the way. We assessed 23 right brain-damaged patients (4 patients with pure perceptual neglect, 8 patients with imagery neglect and 11 patients without neglect) and 17 healthy participants matched for age and education. Our results showed that only patients with imagery neglect had a pervasive disorder in recognizing landmarks met along the route and in mentally navigating the previously learned pathway. Specifically, they were unable to answer navigational questions investigating their mental representation of the pathway. Differently, perceptual neglect patients were able to recognize landmarks as well as answer navigational questions in spite of their exploration disorder. Right brain-damaged patients without neglect showed no deficit on the tasks. In summary, only the imagery neglect patients were unable to build or retrieve a mental representation of the new environment and, thus, failed in performing these tasks. In fact, results showed they were deficient in using a cognitive map of the environment. It is still unknown whether the deficit observed in imagery neglect patients is due to difficulty in building a mental map, recalling it from memory or using it during navigation, leaving unknown the exact point in which the navigational process is compromised
The distribution of the jejunal arteries in the cat
No full textThe arterial supply of the cat jejunum was studied by gross dissection and polyurethane corrosion cast. The results showed that the jejunal arteries, which originate from the cranial mesenteric artery, varied from 5 to 15 in number. Their number was independent of the length of the cranial mesenteric artery as well as of the length of the jejunum. These arteries divided into branches giving rise to a series of orders of division from a minimum of 1 to a maximum of 7. The last orders of division terminated in a series of anastomosing arcades which resulted in a marginal artery coursing only a few millimeters from the mesenteric margin of the jejunum. This artery gave rise to straight arteries (vasa recta), whose mean number was 450 ± 60. According to their length, the vasa recta can be differentiated into short (vasa brevia) and long (vasa longa) branches. The vasa brevia ended branching into the mesenteric side of the jejunum whereas the vasa longa coursed beneath the serosa on the lateral jejunal surfaces, and reached the antimesenteric border. During their course, the vasa recta ramified and anastomosed with each other. Numerous antimesenteric anastomoses between opposing vasa longa were also observed. Based on the literature consulted, due to the large number of vasa recta (approximately one vessel per 2.9 mm of jejunal length) and the rich anastomotic network, the cat jejunum might have a better intramural distribution of blood flow and would seem less predisposed to ischemic phenomena than that of other mammals
The life-course transitions of young women in a Maltese context.
No full textThis study analyzed how a cohort of eight young women who underwent certain difficulties whilst at secondary school experienced their transition from secondary school to either work or further education. It explores changes in their perception of events and happenings that they classified as significant to them, and the influence that these changes of perception had on their evolving life-course. While not formally classified as emotionally or behaviorally challenged, all the participants in this study claimed to have had varying depths of difficulty when at secondary school, some alleging that they had been classified as troublesome by their teachers and others claiming to have seen themselves as disruptive in classroom settings. The study was informed by the participants' voices about how they saw their transitions being forged and has a phenomenological focus
Landmark Recognition and Mental Route Navigation Disorders in Patients with Imagery Neglect and Perceptual Neglect
No full textThe complex relationship between perceptual neglect and imagery neglect is still not completely understand because, at least in part, these disorders depend on are associated with, different neural systems and can be dissociated even in the same patient (Beschin, Basso, & Della Sala, 2000).
Recent studies show that imagery neglect affects specific mechanisms underlying human orientation. In particular, it impairs the ability to manipulate mental representations of the environment and thus prevents the use of previous navigational experience (see for instance Guariglia et al., 2005; Piccardi, 2009; Guariglia & Piccardi, 2010).
In this study, we compared the route learning and delayed recall task performance of imagery neglect patients with pure perceptual neglect patients, patients with no neglect and healthy participants.
They had to learn a circular pathway in an unexplored area of the hospital; it included 13 landmarks and five turning points (three on the right and two on the left). During the learning phase, the participants explored the pathway three times with the examiner, who pointed out the landmarks. At the end of this phase, the participants performed two different tasks: a) Landmark Recognition Task and b) Navigational Questions. The first task included 26 pictures of landmarks (13 target pictures and 13 fillers) located along the pathway that the participants had to recognize. Fillers were the same type of stimuli as the target, but with different characteristics (e.g., two different doors). The second, delayed recall task consisted of 30 questions investigating the participants’ ability to recall a learned pathway and the landmarks encountered along the way.
We assessed 23 right brain-damaged patients (4 patients with pure perceptual neglect, 8 patients with imagery neglect and 11 patients without neglect) and 17 healthy participants matched for age and education.
Our results showed that only patients with imagery neglect had a pervasive disorder in recognizing landmarks met along the route and in mentally navigating the previously learned pathway. Specifically, they were unable to answer navigational questions investigating their mental representation of the pathway. Differently, perceptual neglect patients were able to recognize landmarks as well as answer navigational questions in spite of their exploration disorder. Right brain-damaged patients without neglect showed no deficit on the tasks.
In summary, only the imagery neglect patients were unable to build or retrieve a mental representation of the new environment and, thus, failed in performing these tasks. In fact, results showed they were deficient in using a cognitive map of the environment. It is still unknown whether the deficit observed in imagery neglect patients is due to difficulty in building a mental map, recalling it from memory or using it during navigation, leaving unknown the exact point in which the navigational process is compromised
The use of a fairing and split plate for bluff body noise control
No full textLanding gears have been identified as major noise source contributors during the aircraft’s approach to landing phase. Techniques such as using fairings to alter the flow around the landing gear components have shown to reduce noise . This study investigates methods to further improve the fairing performance. A fundamental study has been performed to understand the influence of using a fairing on a simple cylindrical strut when a split plate is placed in the cavity between the fairing and the strut. Aerodynamic and acoustic tests are performed. Wind tunnel tests equipped with a phased microphone array as well as far field measurements have been conducted out on the fairing-cylindrical strut configuration. The results show that the splitter plate either reduces or eliminates the vortex shedding which in turn reduces noise. This is due to the dividing plate blocking the interaction between the two opposing shear layers aft of the fairing’s trailing edge and reducing their interaction with the downstream strut. Lower velocities around the shell and the strut are observed with the use of the splitter plate as well as reduction of recirculating flow within the shell strut cavity. This alteration in the flow characteristics results in a broadband noise reduction and hence reducing the self-noise generated by the fairing
Natural pollen exposure increases in a dose-dependent way Fraction of exhaled Nitric Oxide (FeNO) levels in patients sensitized to one or more pollen species
No full textBackground: Co-exposures and polysensitization to several pollen species are very common in real life practice. However, little information exists on allergic symptoms and airway inflammation related to natural pollen exposure in large general population samples. Objective: To assess the combined effect of sensitization and/or exposure to one or more pollen species on Fraction of exhaled Nitric Oxide (FeNO) levels. Methods: Within Gene Environment Interactions in Respiratory Diseases (GEIRD) multicase-control study, 1070 adults from the general population of Verona, Italy, underwent a clinical evaluation including standardized interview, spirometry, skin prick test to inhalants and FeNO measurement. Pollen exposure was assumed, when the mean pollen concentration in the previous week was above the cutoff established by the Italian Aerobiological Monitoring Network. Results: Subjects sensitized to one or more pollen species were respectively 15.5% and 29.6%. FeNO levels were directly related to the number of both pollen species around and pollen-related sensitizations. Median FeNO levels were directly related to number of pollen species around and pollen sensitization. FeNO levels increased from 15.4 ppb (p. 25–p. 75 = 9.9–21.0) outside the pollen season to 17.5 ppb (11.2–30.5) when there were ≥3 pollen species around. Likewise FeNO levels rose from 14.8 ppb (10.0–22.3) in not sensitized subjects, to 16.7 (10.1–25.0) in monosensitized and further to 20.4 (12.3–40.6) in poly-sensitized. According to multivariable quantile regression, median FeNO was 17.9 ppb higher (p. 25–p. 75 = 12.5–23.3) for subjects sensitized and exposed to more than one pollen species, compared to subjects who were neither sensitized nor exposed. Differences in FEV1/FVC between groups were less pronounced (−2.0%, −4.1 to 0.1). Median FeNO level was 15.1 ppb (p. 25–p. 75 = 10.0–23.2) in subjects without pollen-related symptoms, 17.8 ppb (12.1–40.2) in those with nasal symptoms only, and 22.7 ppb (14.7–43.0) in those with asthma-like symptoms (p < 0.001). Conclusion and clinical relevance: Airways inflammation, evaluated by FeNO, increases in dose-dependent manner from subjects monosensitized to pollen species to those poly-sensitized, especially when asthma-like symptoms on pollen exposure are also reported. This should be considered by allergists during natural pollen seasons when evaluating both pulmonary function and airways inflammation
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