Role of Cerebellar Interpositus Nucleus in the Genesis and Control of Reflex and Conditioned Eyelid Responses

The role of cerebellar circuits in the acquisition of new motor abilities is still a matter of intensive debate. To establish the contribution of posterior interpositus nucleus (PIN) to the performance and/or acquisition of reflex and classically conditioned responses (CRs) of the eyelid, the effects of microstimulation and/or pharmacological inhibition by muscimol of the nucleus were investigated in conscious cats. Microstimulation of the PIN in naive animals evoked ramp-like eyelid responses with a wavy appearance, without producing any noticeable plastic functional change in the cerebellar and brainstem circuits involved. Muscimol microinjections decreased the amplitude of reflex eyeblinks evoked by air puffs, both when presented alone or when paired with a tone as conditioned stimulus (CS). In half-conditioned animals, muscimol injections also decreased the amplitude and damped the typical wavy profile of CRs, whereas microstimulation of the same sites increased both parameters. However, neither muscimol injections nor microstimulation modified the expected percentage of CRs, suggesting a major role of the PIN in the performance of eyelid responses rather than in the learning process. Moreover, the simultaneous presentation of CS and microstimulation in well trained animals evoked CRs similar in amplitude to the added value of those evoked by the two stimuli presented separately. In contrast, muscimol-injected animals developed CRs to paired CS and microstimulation presentations, larger than those evoked by the two stimuli when presented alone. It is concluded that the PIN contributes to the enhancement of both reflex and conditioned eyelid responses and to the damping of resonant properties of neuromuscular elements controlling eyelid kinematics

Potential Role of Ultrafine Particles in Associations between Airborne Particle Mass and Cardiovascular Health

Numerous epidemiologic time-series studies have shown generally consistent associations of cardiovascular hospital admissions and mortality with outdoor air pollution, particularly mass concentrations of particulate matter (PM) ≤2.5 or ≤10 μm in diameter (PM(2.5), PM(10)). Panel studies with repeated measures have supported the time-series results showing associations between PM and risk of cardiac ischemia and arrhythmias, increased blood pressure, decreased heart rate variability, and increased circulating markers of inflammation and thrombosis. The causal components driving the PM associations remain to be identified. Epidemiologic data using pollutant gases and particle characteristics such as particle number concentration and elemental carbon have provided indirect evidence that products of fossil fuel combustion are important. Ultrafine particles < 0.1 μm (UFPs) dominate particle number concentrations and surface area and are therefore capable of carrying large concentrations of adsorbed or condensed toxic air pollutants. It is likely that redox-active components in UFPs from fossil fuel combustion reach cardiovascular target sites. High UFP exposures may lead to systemic inflammation through oxidative stress responses to reactive oxygen species and thereby promote the progression of atherosclerosis and precipitate acute cardiovascular responses ranging from increased blood pressure to myocardial infarction. The next steps in epidemiologic research are to identify more clearly the putative PM casual components and size fractions linked to their sources. To advance this, we discuss in a companion article (Sioutas C, Delfino RJ, Singh M. 2005. Environ Health Perspect 113:947–955) the need for and methods of UFP exposure assessment

Aortic dissection simulation models for clinical support: fluid-structure interaction vs. rigid wall models

BACKGROUND: The management and prognosis of aortic dissection (AD) is often challenging and the use of personalised computational models is being explored as a tool to improve clinical outcome. Including vessel wall motion in such simulations can provide more realistic and potentially accurate results, but requires significant additional computational resources, as well as expertise. With clinical translation as the final aim, trade-offs between complexity, speed and accuracy are inevitable. The present study explores whether modelling wall motion is worth the additional expense in the case of AD, by carrying out fluid-structure interaction (FSI) simulations based on a sample patient case. METHODS: Patient-specific anatomical details were extracted from computed tomography images to provide the fluid domain, from which the vessel wall was extrapolated. Two-way fluid-structure interaction simulations were performed, with coupled Windkessel boundary conditions and hyperelastic wall properties. The blood was modelled using the Carreau-Yasuda viscosity model and turbulence was accounted for via a shear stress transport model. A simulation without wall motion (rigid wall) was carried out for comparison purposes. RESULTS: The displacement of the vessel wall was comparable to reports from imaging studies in terms of intimal flap motion and contraction of the true lumen. Analysis of the haemodynamics around the proximal and distal false lumen in the FSI model showed complex flow structures caused by the expansion and contraction of the vessel wall. These flow patterns led to significantly different predictions of wall shear stress, particularly its oscillatory component, which were not captured by the rigid wall model. CONCLUSIONS: Through comparison with imaging data, the results of the present study indicate that the fluid-structure interaction methodology employed herein is appropriate for simulations of aortic dissection. Regions of high wall shear stress were not significantly altered by the wall motion, however, certain collocated regions of low and oscillatory wall shear stress which may be critical for disease progression were only identified in the FSI simulation. We conclude that, if patient-tailored simulations of aortic dissection are to be used as an interventional planning tool, then the additional complexity, expertise and computational expense required to model wall motion is indeed justified

Evaluación de la reacción y comportamiento agronómico de variedades de caupí, Vigna unguiculata (L.), ante el ataque del nematodo agallador, Meloidogyne spp., y su efecto posterior en la producción de un cultivo de camote

Informe T&eacute;cnico 2009 Programa de Hortalizas&nbsp; pp.135-145El nematodo agallador (Meloidogyne spp.) es una plaga importante de muchos cultivos alrededor del mundo, siendo su manejo especialmente dif&iacute;cil en cultivos para el mercado de exportaci&oacute;n debido a las limitaciones en el uso de nematicidas. Este estudio fue realizado con el objetivo de determinar la efectividad de diferentes variedades de caup&iacute; [Vigna unguiculata (L.)] usadas como cultivo de cobertura en el manejo de poblaciones de nematodo agallador y su posterior efecto sobre el desarrollo de un cultivo comercial de camote. El estudio fue conducido en dos fases en un lote comercial de la empresa Monty Farms, localizado en La Paz, Honduras. Los tratamientos evaluados incluyeron en la primera fase la siembra de seis variedades de caup&iacute; (5 presumiblemente resistentes y una susceptible) como cultivo de rotaci&oacute;n inmediatamente despu&eacute;s de terminado el ciclo de camote, un control qu&iacute;mico: Vydate 24L (oxamilo) aplicado 35 d&iacute;as despu&eacute;s de siembra (dds) de la variedad local FHIA-C y un testigo comercial (Testigo MF): siembra de sorgo (Sorghum vulgare) como cultivo de rotaci&oacute;n. La segunda fase incluy&oacute; la siembra de camote en las mismas parcelas donde se hab&iacute;an sembrado los tratamientos. Los resultados indicaron que las poblaciones iniciales de nematodo agallador en el suelo se redujeron en todos los tratamientos 40 dds, registr&aacute;ndose la m&aacute;s importante en las parcelas sembradas previamente con las variedades resistentes Big Buff, FHIA-C y testigo qu&iacute;mico, respectivamente. A los 75 dds las poblaciones de nematodo agallador en el suelo fueron bajas (&lt;2 nem/100 cc de suelo) en todas las parcelas sembradas previamente con las variedades resistentes y significativamente diferentes a la observada en la variedad de caup&iacute; susceptible UCR-779 (13 nem/100 cc de suelo). El muestreo de ra&iacute;ces (75 dds) indic&oacute; igualmente que las menores poblaciones de nematodos fueron registradas en los tratamientos CB-27 y CC-85, mientras que la mayor poblaci&oacute;n fue registrada en la variedad susceptible UCR-779. En la segunda etapa (camote) las poblaciones de nematodo agallador se incrementaron hacia el final del ciclo de producci&oacute;n; sin embargo, las menores poblaciones tanto en el suelo como en las ra&iacute;ces fueron registradas en parcelas sembradas previamente por los tratamientos de Caup&iacute; CB-46, testigo qu&iacute;mico, Big Buff y CB-2,7 mientras que las mayores poblaciones de nematodos se registraron en el testigo MF. El rendimiento comercial fue hasta cuatro veces mayor en parcelas donde los tratamientos CB-46 y CB-27 fueron sembrados previamente en comparaci&oacute;n al registrado en el testigo qu&iacute;mico y testigo MF, respectivamente. Nuestros resultados indican que las variedades con resistencia a nematodo agallador importadas de California tienen un alto potencial para ser usadas como cultivos de rotaci&oacute;n en programas de MIP para Nematodo agallador ya que adem&aacute;s brinda beneficios adicionales como ser el control de malezas y el mejoramiento de las propiedades qu&iacute;micas y f&iacute;sicas del suelo. Informe T&eacute;cnico 2009 Programa de Hortalizas&nbsp; pp.135-14

Quality of life in patients with advanced gastric cancer: a randomized trial comparing docetaxel, cisplatin, 5-FU (TCF) with epirubicin, cisplatin, 5-FU (ECF)

BACKGROUND: Health related quality of life (HRQOL) is an important outcome after treatment for upper gastrointestinal carcinoma. This study aimed to compare HRQOL in patients with advanced gastric cancer (GC) receiving either a standard or an experimental treatment. METHODS: Seventy-one patients have been treated in Cancer Institute (Tehran, Iran) with docetaxel, cisplatin, 5 FU (TCF) or epirubicin, cisplatin, 5-FU (ECF) and were followed from Jan 2002 to Jan 2005. End points were response rate, HRQOL and survival. HRQOL was assessed using the EORCT QLQ-C30 at baseline and after the third cycle of chemotherapy. RESULTS: The baseline HRQOL scores were comparable between two groups. After treatment improvement was seen in a number of items and domains except for cognitive functioning, and diarrhoea. Pain decreased and physical functioning improved in both groups. However, only the TCF group showed statistically and clinically meaningful improvement in global QOL (P = 0.001). Surgical and pathologic response was better with TCF but there was no difference in survival rate between two groups. CONCLUSION: Docetaxel based treatment (TCF) showed better palliation and improvement of global QOL as compared with epirubicin based treatment (ECF). However, it seems that regardless of treatment offered, effective chemotherapy was the most important factor affecting QOL in these patients

The momentum analyticity of two-point correlators from perturbation theory and AdS/CFT

The momentum plane analyticity of two point function of a relativistic thermal field theory at zero chemical potential is explored. A general principle regarding the location of the singularities is extracted. In the case of the N=4 supersymmetric Yang-Mills theory at large $N_c$, a qualitative change in the nature of the singularity (branch points versus simple poles) from the weak coupling regime to the strong coupling regime is observed with the aid of the AdS/CFT correspondence.Comment: 18 pages, 3 figures, typos fixed, 1 figure update