136 research outputs found
Analysis of behavior of the respiratory system in ARDS patients: effects of flow, volume, and time.
No full textThe effects of inspiratory flow (V) and inflation volume (delta V) on the mechanical properties of the respiratory system in eight ARDS patients were investigated using the technique of rapid airway occlusion during constant-flow inflation. We measured interrupter resistance (Rint,rs), which in humans represents airway resistance, the additional resistance (delta Rrs) due to viscoelastic pressure dissipations and time constant inequalities, and static (Est,rs) and dynamic (Edyn,rs) elastance. The results were compared with a previous study on 16 normal anesthetized paralyzed humans (D'Angelo et al. J. Appl. Physiol. 67: 2556-2564, 1989). We observed that 1) resistance and elastance were higher in ARDS patients; 2) with increasing V, Rint,rs and Est,rs did not change, delta Rrs decreased progressively, and Edyn,rs increased progressively; 3) with increasing delta V, Rint,rs decreased slightly, delta Rrs increased progressively, and Est,rs and Edyn,rs showed an initial decrease followed by a secondary increase noted only in the ARDS patients. The above findings could be explained in terms of a model incorporating a standard resistance in parallel with a standard elastance and a series spring-and-dashpot body that represents the stress adaptation units within the tissues of the respiratory system
Analysis of behavior of the respiratory system in ARDS patients : effects of flow, volume, and time
No full textThe effects of inspiratory flow (V) and inflation volume (delta V) on the mechanical properties of the respiratory system in eight ARDS patients were investigated using the technique of rapid airway occlusion during constant-flow inflation. We measured interrupter resistance (Rint,rs), which in humans represents airway resistance, the additional resistance (delta Rrs) due to viscoelastic pressure dissipations and time constant inequalities, and static (Est,rs) and dynamic (Edyn,rs) elastance. The results were compared with a previous study on 16 normal anesthetized paralyzed humans (D'Angelo et al. J. Appl. Physiol. 67: 2556-2564, 1989). We observed that 1) resistance and elastance were higher in ARDS patients; 2) with increasing V, Rint,rs and Est,rs did not change, delta Rrs decreased progressively, and Edyn,rs increased progressively; 3) with increasing delta V, Rint,rs decreased slightly, delta Rrs increased progressively, and Est,rs and Edyn,rs showed an initial decrease followed by a secondary increase noted only in the ARDS patients. The above findings could be explained in terms of a model incorporating a standard resistance in parallel with a standard elastance and a series spring-and-dashpot body that represents the stress adaptation units within the tissues of the respiratory system
Nanoparticles as Contrast Agents for The Diagnosis of Alzheimer’s Disease: A Systematic Review
No full textNanoparticle (NP)-based magnetic contrast agents have opened the potential for MRI to be used for early diagnosis of Alzheimer’s disease (AD). This article aims to review the current progress of research in this field. A comprehensive literature search was performed based on PubMed, Medline, EMBASE, PsychINFO and Scopus databases using the following terms: ‘Alzheimer’s disease’ AND ‘nanoparticles’ AND ‘Magnetic Resonance Imaging.’ 33 studies were included that described the development and utility of various NPs for AD imaging, including their coating, functionalization, MRI relaxivity, toxicity and bioavailability. NPs show immense promise for neuroimaging, due to superior relaxivity and biocompatibility compared with currently available imaging agents. Consistent reporting is imperative for further progress in this field.M Ulanova is a recipient of the Australian Postgraduate Award PhD scholarship. N Braidy is a recipient of the Australian Research Council Discovery Early Career Award (DE170100628). N Braidy and P Sachdev acknowledge funding from Yulgibar/Dementia Australia. L Gloag, J Gooding and R Tilley acknowledge funding under the Australian Research Council Linkage grant (LP150101014). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.Peer-reviewe
Effect du debit et du volume sur la resistence du system respiratoire chez les patients ventilées.
No full textEffect of coiling on the electronic properties along single-wall carbon nanotubes
No full textStraight and coiled single-wall carbon nanotubes (SWCNTs) synthesized by laser vaporization were dispersed on highly oriented pyrolitic graphite. Their morphology and electrical properties were investigated by scanning tunneling microscopy (STM). STM images revealed that the SWCNTs (either straight or coiled) often self-organize into bundles of two or more tubes and are rarely found alone. The conductance measured along a periodically coiled CNT was found to increase at locations where the CNT is squeezed, while it decreases significantly in unsqueezed regions characterized by an unperturbed hexagonal network. This provides experimental evidence of significant conductance modulation along a one-dimensional system on the nanometer scale. © 2004 American Institute of Physics
OXYGEN DELIVERY-CONSUMPTION RELATIONSHIP IN SEPTIC ADULT RESPIRATORY-DISTRESS SYNDROME PATIENTS - THE EFFECTS OF POSITIVE END-EXPIRATORY PRESSURE
No full textFlow and volume dependence of respiratory system flow resistance in patients with adult respiratory distress syndrome
No full textUsing a simple and rapid technique, we studied the flow and volume dependence of the total resistance of the respiratory system (Rrs) in six patients with ARDS. At any given inflation volume, Rrs decreased progressively with increasing flow (V) according to the following hyperbolic function: Rrs = a/V + b, where a and b are constants. At any fixed inflation flow, Rrs increased progressively with increasing inflation volume. The observed flow and volume dependence of Rrs is probably mainly due to the viscoelastic properties of the pulmonary and chest wall tissues. The flow and volume dependence of Rrs found in the patients with ARDS is qualitatively similar to that previously observed in normal anesthetized paralyzed subjects. In ARDS, however, Rrs was considerably greater than in the normal subjects, indicating that besides a low respiratory compliance ARDS is characterized by a high flow resistance. This mainly reflects increased effective flow resistance of the pulmonary and chest wall tissues, although airway resistance is also higher than norma
OXIGEN DELIVERY-CONSUMPTION RELATIONSHIP IN SEPTIC ADULT RESPIRATORY-DISTRESS SYNDROME PATIENTS - THE EFFECTS OF POSITIVE END-EXPIRATORY PRESSURE
No full textEvaluation of Hypericum androsaemum L. red fruit effects in a mouse model of post-stroke depression
No full textStroke is one of the most important cerebrovascular diseases, and is classified into two categories, hemorrhagic and ischemic stroke, with the latter causing infarction and brain injury during which alteration of antioxidant defenses and generation of reactive oxygen species (ROS) cause neuronal dysfunction and death.1 Oxidative stress thus plays a pivotal role for the development of major depressive disorder (MDD). Indeed, depression is an important and frequent neuropsychiatric disorder occurring in stroke patients.2
Searching for medicinal plants endowed with antidepressant and antioxidant properties, thus potentially useful in the treatment of post-stroke depression, we focused our attention on Hypericum androsaemum L., an evergreen shrub growing in thermophilous woods and considered one of the most used traditional remedies in the genus Hypericum throughout the Mediterranean area.3,4 In particular, we assumed that the antioxidant potential of H. androsaemum berry-like fruits, previously demonstrated,3,4 may be helpful in treating the symptoms of post-stroke depression. For the purpose, a mouse model of post-stroke depression was used. Ischemic stroke was induced in mice by bilateral common carotid artery occlusion and the antidepressive-like effects of two aqueous extracts of H. androsaemum red fruits at two doses (15 and 30 mg/kg bw i.p.) were evaluated by despair swimming test (DST) and tail suspension test (TST). Furthermore, the oxidative stress in mice brain was examined by measuring the TBARS, SOD, Cat and GSH levels. Finally, the content of ten bioactive compounds in the H. androsaemum red berry extracts was measured by HPLC-DAD analysis.
Results showed that H. androsaemum red berry aqueous extracts reduced the overall symptoms of post-stroke depression, restoring near-normal behavior. Correlation between pharmacological results and the presence in the fruit extract of some bioactive compounds was discussed
Uptake and mitochondrial dysfunction of alpha-synuclein in human astrocytes, cortical neurons and fibroblasts
Get PDF© 2013 Braidy et al.; licensee BioMed Central Ltd.
This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The accumulation and aggregation of alpha-synuclein (α-syn) in several tissue including the brain is a major
pathological hallmark in Parkinson’s disease (PD). In this study, we show that α-syn can be taken up by primary
human cortical neurons, astrocytes and skin-derived fibroblasts in vitro. Our findings that brain and peripheral cells
exposed to α-syn can lead to impaired mitochondrial function, leading to cellular degeneration and cell death,
provides additional evidence for the involvement of mitochondrial dysfunction as a mechanism of toxicity of α-syn
in human cells
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