784 research outputs found
Rotavirus-Associated Necrotizing Enterocolitis After Cardiac Catheterization in Infants
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72446/1/j.1540-8183.1991.tb01020.x.pd
Metatarsophalangeal joint function during sprinting: A comparison of barefoot and sprint spike shod foot conditions
This is the authors' post print as accepted for publication in Journal of Applied Biomechanics. The published version is available at http://journals.humankinetics.com/jabThe metatarsophalangeal joint is an important contributor to lower limb energetics during sprint running. This study compared the kinematics, kinetics and energetics of the metatarsophalangeal joint during sprinting barefoot and wearing standardised sprint spikes. The aim of this investigation was to determine whether standard sprinting footwear alters the natural motion and function of the metatatarsophalangeal joint exhibited during barefoot sprint running. Eight trained sprinters performed maximal sprints along a runway, four sprints in each condition. Three dimensional high speed (1000 Hz) kinematic and kinetic data were collected at the 20 m point. Joint angle, angular velocity, moment, power and energy were calculated for the metatarsophalangeal joint. Sprint spikes significantly increase sprinting velocity (0.3 m/s average increase), yet limit the range of motion about the metatarsophalangeal joint (17.9 % average reduction) and reduce peak dorsiflexion velocity (25.5 % average reduction), thus exhibiting a controlling affect over the natural behaviour of the foot. However, sprint spikes improve metatarsophalangeal joint kinetics by significantly increasing the peak metatarsophalangeal joint moment (15 % average increase) and total energy generated during the important push-off phase (0.5 J to 1.4 J). The results demonstrate substantial changes in metatarsophalangeal function and potential improvements in performance-related parameters due to footwear
An Experimental Biomimetic Platform for Artificial Olfaction
Artificial olfactory systems have been studied for the last two decades mainly from the point of view of the features of olfactory neuron receptor fields. Other fundamental olfaction properties have only been episodically considered in artificial systems. As a result, current artificial olfactory systems are mostly intended as instruments and are of poor benefit for biologists who may need tools to model and test olfactory models. Herewith, we show how a simple experimental approach can be used to account for several phenomena observed in olfaction
Extracellular Matrix Aggregates from Differentiating Embryoid Bodies as a Scaffold to Support ESC Proliferation and Differentiation
Embryonic stem cells (ESCs) have emerged as potential cell sources for tissue engineering and regeneration owing to its virtually unlimited replicative capacity and the potential to differentiate into a variety of cell types. Current differentiation strategies primarily involve various growth factor/inducer/repressor concoctions with less emphasis on the substrate. Developing biomaterials to promote stem cell proliferation and differentiation could aid in the realization of this goal. Extracellular matrix (ECM) components are important physiological regulators, and can provide cues to direct ESC expansion and differentiation. ECM undergoes constant remodeling with surrounding cells to accommodate specific developmental event. In this study, using ESC derived aggregates called embryoid bodies (EB) as a model, we characterized the biological nature of ECM in EB after exposure to different treatments: spontaneously differentiated and retinoic acid treated (denoted as SPT and RA, respectively). Next, we extracted this treatment-specific ECM by detergent decellularization methods (Triton X-100, DOC and SDS are compared). The resulting EB ECM scaffolds were seeded with undifferentiated ESCs using a novel cell seeding strategy, and the behavior of ESCs was studied. Our results showed that the optimized protocol efficiently removes cells while retaining crucial ECM and biochemical components. Decellularized ECM from SPT EB gave rise to a more favorable microenvironment for promoting ESC attachment, proliferation, and early differentiation, compared to native EB and decellularized ECM from RA EB. These findings suggest that various treatment conditions allow the formulation of unique ESC-ECM derived scaffolds to enhance ESC bioactivities, including proliferation and differentiation for tissue regeneration applications. © 2013 Goh et al
Synchronous malignant vagal paraganglioma with contralateral carotid body paraganglioma treated by radiation therapy
Paragangliomas are rare tumors and very few cases of malignant vagal paraganglioma with synchronous carotid body paraganglioma have been reported. We report a case of a 20-year old male who presented with slow growing bilateral neck masses of eight years duration. He had symptoms of dysphagia to solids, occasional mouth breathing and hoarseness of voice. Fine needle aspiration cytology (FNAC) performed where he lived showed a sinus histiocytosis and he was administered anti-tubercular treatment for six months without any improvement in his symptoms. His physical examination revealed pulsatile, soft to firm, non-tender swellings over the anterolateral neck confined to the upper-mid jugulo-diagastric region on both sides. Direct laryngoscopy examination revealed a bulge on the posterior pharyngeal wall and another over the right lateral pharyngeal wall. Magnetic resonance imaging (MRI), 99mTc-labeled octreotide scan and angiography diagnosed the swellings as carotid body paraganglioma, stage III on the right side with left-sided vagal malignant paraganglioma. Surgery was ruled out as a high morbidity with additional risk to life was expected due to the highly vascular nature of the tumor. The patient was treated with radiation therapy by image guided radiation to a dose of 5040cGy in 28 fractions. At a follow-up at 16 months, the tumors have regressed bilaterally and the patient can take solids with ease
Study protocol: Determinants of participation and quality of life of adolescents with cerebral palsy: a longitudinal study (SPARCLE2)
<p>Abstract</p> <p>Background</p> <p>Children and adults with impairments such as cerebral palsy have lower participation in life situations than able-bodied people. Less is known about their subjective perception of their lives, called their quality of life.</p> <p>During adolescence, rapid physical and psychological changes occur; although these may be more difficult for disabled than for able-bodied adolescents, little research has examined the lives of disabled adolescents.</p> <p>In 2003-4 a European Union funded project, SPARCLE, visited 818 children aged 8-12 years with cerebral palsy, sampled from population-based registers in nine European regions. The quality of life reported by these disabled children was similar to that of the general population but their participation was lower; levels of participation varied between countries even for children with similar severity of cerebral palsy.</p> <p>We are currently following up these children, now aged 13-17 years, to identify (i) to what extent contemporaneous factors (pain, impairment, psychological health and parental stress) predict their participation and quality of life, (ii) what factors modify how participation and quality of life at age 8-12 years are associated with participation and quality of life in adolescence, and (iii) whether differences between European countries in participation and quality of life can be explained by variations in environmental factors.</p> <p>Methods/Design</p> <p>Trained researchers will visit families to administer questionnaires to capture the adolescents' type and severity of impairment, socio-demographic characteristics, participation, quality of life, psychological health, pain, environmental access and parental stress. We will use multivariable models (linear, logistic or ordinal) to assess how adolescent participation, quality of life, psychological health, pain, environmental access and parental stress, vary with impairment and socio-demographic characteristics and, where possible, how these outcomes compare with general population data. For participation and quality of life, longitudinal analyses will assess to what extent these are predicted by corresponding levels in childhood and what factors modify this relationship. Structural equation modelling will be used to identify indirect relationships mediated by other factors.</p
The Hubble Constant
I review the current state of determinations of the Hubble constant, which
gives the length scale of the Universe by relating the expansion velocity of
objects to their distance. There are two broad categories of measurements. The
first uses individual astrophysical objects which have some property that
allows their intrinsic luminosity or size to be determined, or allows the
determination of their distance by geometric means. The second category
comprises the use of all-sky cosmic microwave background, or correlations
between large samples of galaxies, to determine information about the geometry
of the Universe and hence the Hubble constant, typically in a combination with
other cosmological parameters. Many, but not all, object-based measurements
give values of around 72-74km/s/Mpc , with typical errors of 2-3km/s/Mpc.
This is in mild discrepancy with CMB-based measurements, in particular those
from the Planck satellite, which give values of 67-68km/s/Mpc and typical
errors of 1-2km/s/Mpc. The size of the remaining systematics indicate that
accuracy rather than precision is the remaining problem in a good determination
of the Hubble constant. Whether a discrepancy exists, and whether new physics
is needed to resolve it, depends on details of the systematics of the
object-based methods, and also on the assumptions about other cosmological
parameters and which datasets are combined in the case of the all-sky methods.Comment: Extensively revised and updated since the 2007 version: accepted by
Living Reviews in Relativity as a major (2014) update of LRR 10, 4, 200
Nonradioactive heteroduplex tracking assay for the detection of minority-variant chloroquine-resistant Plasmodium falciparum in Madagascar
<p>Abstract</p> <p>Background</p> <p>Strains of <it>Plasmodium falciparum </it>genetically resistant to chloroquine (CQ) due to the presence of <it>pfcrt </it>76T appear to have been recently introduced to the island of Madagascar. The prevalence of such resistant genotypes is reported to be low (< 3%) when evaluated by conventional PCR. However, these methods are insensitive to low levels of mutant parasites present in patients with polyclonal infections. Thus, the current estimates may be an under representation of the prevalence of the CQ-resistant <it>P. falciparum </it>isolates on the island. Previously, minority variant chloroquine resistant parasites were described in Malawian patients using an isotopic heteroduplex tracking assay (HTA), which can detect <it>pfcrt </it>76T-bearing <it>P. falciparum </it>minority variants in individual patients that were undetectable by conventional PCR. However, as this assay required a radiolabeled probe, it could not be used in many resource-limited settings.</p> <p>Methods</p> <p>This study describes a digoxigenin (DIG)-labeled chemiluminescent heteroduplex tracking assay (DIG-HTA) to detect <it>pfcrt </it>76T-bearing minority variant <it>P. falciparum</it>. This assay was compared to restriction fragment length polymorphism (RFLP) analysis and to the isotopic HTA for detection of genetically CQ-resistant parasites in clinical samples.</p> <p>Results</p> <p>Thirty one clinical <it>P. falciparum </it>isolates (15 primary isolates and 16 recurrent isolates) from 17 Malagasy children treated with CQ for uncomplicated malaria were genotyped for the <it>pfcrt </it>K76T mutation. Two (11.7%) of 17 patients harboured genetically CQ-resistant <it>P. falciparum </it>strains after therapy as detected by HTA. RFLP analysis failed to detect any <it>pfcrt </it>K76T-bearing isolates.</p> <p>Conclusion</p> <p>These findings indicate that genetically CQ-resistant <it>P. falciparum </it>are more common than previously thought in Madagascar even though the fitness of the minority variant <it>pfcrt </it>76T parasites remains unclear. In addition, HTAs for malaria drug resistance alleles are promising tools for the surveillance of anti-malarial resistance. The use of a non-radioactive label allows for the use of HTAs in malaria endemic countries.</p
Steroid-refractory ulcerative colitis treated with corticosteroids, metronidazole and vancomycin: a case report
BACKGROUND: Increasing evidence elucidating the pathogenic mechanisms of ulcerative colitis (UC) has accumulated and the disease is widely assumed to be the consequence of genetic susceptibility and an abnormal immune response to commensal bacteria. However evidence regarding an infectious etiology in UC remains elusive. CASE PRESENTATION: We report a provocative case of UC with profound rheumatologic involvement directly preceded by Clostridium difficile infection and accompanying fever, vomiting, bloody diarrhea, and arthritis. Colonic biopsy revealed a histopathology suggestive of UC. Antibiotic treatment eliminated detectable levels of enteric pathogens but did not abate symptoms. Resolution of symptoms was procurable with oral prednisone, but tapering of corticosteroids was only achievable in combination therapy with vancomycin and metronidazole. CONCLUSIONS: An infectious pathogen may have both precipitated and exacerbated autoimmune disease attributes in UC, symptoms of which could be resolved only with a combination of corticosteroids, vancomycin and metronidazole. This may warrant the need for more perceptive scrutiny of C. difficile and the like in patients with UC
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