994 resultados para Sub-pixel techniques
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Different molecular-genetic methods were used to identify a cohort of Leishmania strains from natural foci of zoonotic cutaneous leishmaniasis located in Central Asia, on the former USSR territory. The results obtained using isoenzymes, PCR, restriction fragment length polymorphisms of kDNA and molecular hybridization techniques are discussed in terms of their applicability, discrimination power and feasibility for answering questions related to molecular epidemiological research and for detecting mixed Leishmania infections
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Neuroimaging techniques provide valuable tools for diagnosing Alzheimer's disease (AD), monitoring disease progression and evaluating responses to treatment. There is currently a wide array of techniques available including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and, for recording electrical brain activity, electroencephalography (EEG). The choice of technique depends on the contrast between tissues of interest, spatial resolution, temporal resolution, requirements for functional data and the probable number of scans required. For example, while PET, CT and MRI can be used to differentiate between AD and other dementias, MRI is safer and provides better contrast of soft tissues. Neuroimaging is a technique spanning many disciplines and requires effective communication between doctors requesting a scan of a patient or group of patients and those with technical expertise. Consideration and discussion of the most suitable type of scan and the necessary settings to achieve the best results will help ensure appropriate techniques are chosen and used effectively. Neuroimaging techniques are currently expanding understanding of the structural and functional changes that occur in dementia. Further research may allow identification of early neurological signs ofAD, before clinical symptoms are evident, providing the opportunity to test preventative therapies. CombiningMRI and machine learning techniques may be a powerful approach to improve diagnosis ofAD and to predict clinical outcomes.
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We investigated the neural basis for spontaneous chemo-stimulated increases in ventilation in awake, healthy humans. Blood oxygen level dependent (BOLD) functional MRI was performed in nine healthy subjects using T2 weighted echo planar imaging. Brain volumes (52 transverse slices, cortex to high spinal cord) were acquired every 3.9 s. The 30 min paradigm consisted of six, 5-min cycles, each cycle comprising 45 s of hypoxic-isocapnia, 45 s of isooxic-hypercapnia and 45 s of hypoxic-hypercapnia, with 55 s of non-stimulatory hyperoxic-isocapnia (control) separating each stimulus period. Ventilation was significantly (p<0.001) increased during hypoxic-isocapnia, isooxic-hypercapnia and hypoxic-hypercapnia (17.0, 13.8, 24.9 L/min respectively) vs. control (8.4 L/min) and was associated with significant (p<0.05, corrected for multiple comparisons) signal increases within a bilateral network that included the basal ganglia, thalamus, red nucleus, cerebellum, parietal cortex, cingulate and superior mid pons. The neuroanatomical structures identified provide evidence for the spontaneous control of breathing to be mediated by higher brain centres, as well as respiratory nuclei in the brainstem.
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Insight into the function of sleep may be gained by studying animals in the ecological context in which sleep evolved. Until recently, technological constraints prevented electroencephalogram (EEG) studies of animals sleeping in the wild. However, the recent development of a small recorder (Neurologger 2) that animals can carry on their head permitted the first recordings of sleep in nature. To facilitate sleep studies in the field and to improve the welfare of experimental animals, herein, we test the feasibility of using minimally invasive surface and subcutaneous electrodes to record the EEG in barn owls. The EEG and behaviour of four adult owls in captivity and of four chicks in a nest box in the field were recorded. We scored a 24-h period for each adult bird for wakefulness, slow-wave sleep (SWS), and rapid-eye movement (REM) sleep using 4 s epochs. Although the quality and stability of the EEG signals recorded via subcutaneous electrodes were higher when compared to surface electrodes, the owls' state was readily identifiable using either electrode type. On average, the four adult owls spent 13.28 h awake, 9.64 h in SWS, and 1.05 h in REM sleep. We demonstrate that minimally invasive methods can be used to measure EEG-defined wakefulness, SWS, and REM sleep in owls and probably other animals.
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PH Health Protection Sub-Group Interim Report January 2006
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Anterior and middle skull base tumors, mainly meningiomas, are usually operated on using a sub-frontal route with a microscope. With modern radiotherapy, the goal of skull base surgery moves from a radical surgery with high rate of side effect to a functional concept that aims to remove as much as possible of the tumor without compromising the neurological status of patients. Minimally skull base surgery benefits from keyhole and endoscopy techniques. For 3 2 decades, the development of endoscopy helps to imagine innovative approaches for skull base tumors such as the endonasal route. Nonetheless, CSF leak issue and the absence of direct control of the tumor margins may limit the interest of such a route. Keyhole craniotomies have been developed with microscope but vision issue limits their use. Combining advantages of both techniques appears therefore natural and gave birth to intracranial assisted and more recently to fully endoscopic keyhole surgery. For anterior or middle skull base tumors, Keyhole supraorbital approaches can be done either by a trans-eyebrow or trans-eyelid routes. A step-by-step description of these fully endoscopic alternative routes summarizing advantages and drawbacks compared to others (traditional sub-frontal or more recent endonasal approaches) is reported in this chapter by the authors.
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Rapid response to: Ortegón M, Lim S, Chisholm D, Mendis S. Cost effectiveness of strategies to combat cardiovascular disease, diabetes, and tobacco use in sub-Saharan Africa and South East Asia: mathematical modelling study. BMJ. 2012 Mar 2;344:e607. doi: 10.1136/bmj.e607. PMID: 22389337.
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The subthalamic nucleus (STN) is a small, glutamatergic nucleus situated in the diencephalon. A critical component of normal motor function, it has become a key target for deep brain stimulation in the treatment of Parkinson's disease. Animal studies have demonstrated the existence of three functional sub-zones but these have never been shown conclusively in humans. In this work, a data driven method with diffusion weighted imaging demonstrated that three distinct clusters exist within the human STN based on brain connectivity profiles. The STN was successfully sub-parcellated into these regions, demonstrating good correspondence with that described in the animal literature. The local connectivity of each sub-region supported the hypothesis of bilateral limbic, associative and motor regions occupying the anterior, mid and posterior portions of the nucleus respectively. This study is the first to achieve in-vivo, non-invasive anatomical parcellation of the human STN into three anatomical zones within normal diagnostic scan times, which has important future implications for deep brain stimulation surgery.
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Purpose: To investigate the effect of the systematized use of intraluminal stents in Baerveldt shunts (BS) on early postoperative IOP control and complication rates. Methods: One hundred and twenty eyes with medically uncontrolled glaucoma were prospectively recruited to undergo BS implantation at Jules Gonin Eye Hospital, Switzerland. Baerveldt shunts were stented (full-length of the intraluminal tube) using a Supramid® 3.0 suture. A minority of shunts (37%) were also ligated intraoperatively and laser suture lysis performed postoperatively. Stent removals, either partial (retraction of 5mm) or complete, were carried out according to a predetermined protocol. Surgery was considered a success when IOP was ≤ 21mmHg and a minimum of 20% reduction from baseline was achieved with/without glaucoma medication (GMs). Hypotony related complications were defined as: choroidal effusions, shallow AC, hypotonous maculopathy or IOP≤5mmHg for over 2 weeks. Results: Mean age was 61.8 years (± standard deviation; ±21.5). Mean follow-up was 17.1 (±7.9) months. Mean preoperative IOP was 26.9 mmHg; mean IOP on the last visit 13.2 mmHg (p<0.001). At year one, the success rate was 87%. In 90% of eyes, IOP was ≤18 mmHg at last visit. Mean number of preoperatively GMs was 3.1; postoperatively 1.4 (p<0.001). Stent removals were performed in 87% of eyes (24% partial; 61% complete). 13% of eyes required no stent removal to reach target IOP. Complications were minor and infrequent (16%) and only 7% were hypotony related. Conclusions: Systematized use of intraluminal stents with Baerveldt aqueous shunts resulted in gradual and controlled IOP lowering with minimal hypotony-related complications. This may have important implications on clinical practice, given the rising rates of aqueous shunt implantation.
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L'estudi a nivell molecular de la ruta de senyalització activada per TGF-B té un impacte notable en el panorama actual donada la seva implicació en processos autoimmunitaris i carcinogènics. D'altra banda, l'elucidació a nivell estructural dels mecanismes moleculars que permeten a les ubiquitin lligases de tipus E3 marcar específicament llurs dianes per a la degradació proteosòmica - entre d'altres - resulta fonamental donada la seva importància pel que fa al control sobre el turnover proteic a nivell intracel•lular. En aquest projecte es pretén elucidar els mecanismes d'activació i catlàlisi de les ubiquitin lligases E3 tipus HECT Smurf1 i Nedd4L al mateix temps que se n'estudia la implicació en la regulació dels agents missatgers de la ruta del TGF-B. Així, la tasca es divideix en tres sub-projectes els quals se centren en a) l'estudi de la interacció d'aquestes lligases amb llurs dianes; b) l'elucidació del mecanisme d'activació i c) del de catàlisi d'aquests enzims. Per tal d'assolir aquests objectius ens servim principalment dels avantatges que ens aporta la Ressonància Magnètica Nuclear i altres tècniques biofísiques, principalment la ITC. Durant el temps que he gaudit de la beca FI, m'he centrat principalment en la preparació de pèptids per SPPS, llur purificació per HPLC i caracterització per MS i RMN. Aquests pèptids representen diferents patrons de fosforilació de certes dianes de les lligases esmentades, de manera que han estat emprats per a l'estudi d'interaccions proteïna-proteïna per ITC i RMN. M'he iniciat doncs en l'ús d'aquestes tècniques. D'altra banda, també he preparat mostres protèiques mitjançant l'ús de sistemes d'expressió bacterians basats en E.coli, incloent l'amplificació i clonació del gen que codifica per la proteïna d'interés així com la seva expressió, purificació i caracterització per MS i RMN.
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In April 1999, the Minister of Health and Children asked the National Cancer Forum to report and make recommendations on the development of breast services for symptomatic women. The Forum established a subgroup to undertake this exercise, under the Chairmanship of Prof J. Fennelly. Download the Report here