10 research outputs found
Receiver operating characteristics for CRP and malaria.
No full textReceiver operating characteristics for CRP and malaria.</p
S1 Database -
No full textBackgroundC reactive protein (CRP), a marker for the presence of inflammation, has been extensively studied for distinguishing bacterial from non-bacterial infection in febrile patients, but its role in excluding malaria in the febrile child has not been thoroughly evaluated.MethodThis was a cross-sectional study at the Douala Gyneco-Obstetric and Pediatric Hospital which included all patients between the ages of one month and 16 years presenting with fever. Consenting patients received complete clinical examinations, then venous blood samples were collected and tested for CRP values, bacterial infection and malaria.ResultsSamples of 220 children were analyzed. 142/220 had viral infections, 50/220 had malaria and 49/220 had bacterial infections. 7/220 had both malaria and bacterial infection. There was no significant difference between mean CRP values in malaria and bacterial infection (p = 1), but CRP means were significantly higher in malaria/bacterial infection than in viral infection (pConclusionCRP can effectively exclude malaria and bacterial infection in febrile children in low-resource settings without the need for additional tests.</div
Distribution of CRP levels according to final diagnosis.
No full textDistribution of CRP levels according to final diagnosis.</p
Positive and negative values for CRP and bacterial infection using optimal cut-off.
No full textPositive and negative values for CRP and bacterial infection using optimal cut-off.</p
Demographic and clinical characteristics of the study population.
No full textDemographic and clinical characteristics of the study population.</p
Positive and negative values for CRP and malaria using optimal cut-off.
No full textPositive and negative values for CRP and malaria using optimal cut-off.</p
Receiver operating characteristics curve for CRP in bacterial infection.
No full textReceiver operating characteristics curve for CRP in bacterial infection.</p
Transient rhythmic network activity in the somatosensory cortex evoked by distributed input in vitro
No full textThe initiation and maintenance of physiological and pathophysiological oscillatory activity depends on the synaptic interactions within neuronal networks. We studied the mechanisms underlying evoked transient network oscillation in acute slices of the adolescent rat somatosensory cortex and modeled its underpinning mechanisms. Oscillations were evoked by brief spatially distributed noisy extracellular stimulation, delivered via bipolar electrodes. Evoked transient network oscillation was detected with multi-neuron patch-clamp recordings under different pharmacological conditions. The observed oscillations are in the frequency range of 2-5 Hz and consist of 4-12 mV large, 40-150 ms wide compound synaptic events with rare overlying action potentials. This evoked transient network oscillation is only weakly expressed in the somatosensory cortex and requires increased [K+]o of 6.25 mM and decreased [Ca2+]o of 1.5 mM and [Mg2+]o of 0.5 mM. A peak in the cross-correlation among membrane potential in layers II/III, IV and V neurons reflects the underlying network-driven basis of the evoked transient network oscillation. The initiation of the evoked transient network oscillation is accompanied by an increased [K+]o and can be prevented by the K+ channel blocker quinidine. In addition, a shift of the chloride reversal potential takes place during stimulation, resulting in a depolarizing type A GABA (GABAA) receptor response. Blockade of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-proprionate (AMPA), N-methyl-D-aspartate (NMDA), or GABA(A) receptors as well as gap junctions prevents evoked transient network oscillation while a reduction of AMPA or GABA(A) receptor desensitization increases its duration and amplitude. The apparent reversal potential of -27 mV of the evoked transient network oscillation, its pharmacological profile, as well as the modeling results suggest a mixed contribution of glutamatergic, excitatory GABAergic, and gap junctional conductances in initiation and maintenance of this oscillatory activity. With these properties, evoked transient network oscillation resembles epileptic afterdischarges more than any other form of physiological or pathophysiological neocortical oscillatory activity
Caractérisation de la couche limite océanique pendant les campagnes EGEE/AMMA dans l'Atlantique équatorial Est
No full textCes travaux de thèse s'intègrent dans les objectifs du projet international d'Analyse de la Mousson Africaine (AMMA). Ils abordent la caractérisation des échanges entre l'océan et l'atmosphère dans l'Atlantique Equatorial Est (AEE) de l'échelle diurne à inter annuelle à partir de données d'observation et de la modélisation numérique. Ces échanges sont d'une très grande importance pour le déclenchement de la Mousson Africaine qui détermine en grande partie la saison des pluies en Afrique de l'Ouest. Nous montrons que les paramètres de la couche de mélange océanique dans le GG sont principalement pilotées, à l'échelle diurne, par les flux de chaleur et les processus de sub-surface (l'entraînement, le mélange vertical) et nous montrons aussi qu'à partir d'une paramétrisation de la turbulence océanique (TKE) fermée à l'ordre 1.5, on parvient à restituer la turbulence océanique observée dans cette région. Afin de quantifier le rôle de la tension du vent sur la variabilité des paramètres de la couche de mélange océanique, nous utilisons un modèle linéaire forcé par les anomalies de la tension du vent. Les résultats montrent que près de l'équateur (3°S-3°N), le signal est retrouvé ; par contre de part et d'autre de la bande 3°S-3°N, les amplitudes des paramètres de la couche de mélange sont très largement sous estimés, ce qui montre que la tension du vent n'est pas le seul paramètre à moduler la variabilité de la température surface à ces latitudes. Les bilans de chaleur intégrés sur la couche de mélange ont permis de montrer le rôle des flux de chaleur et du mélange vertical dans l'AEE. En effet, l'AEE est subdivisé en plusieurs boîtes en tenant compte de la dynamique et de la thermodynamique et dans chaque boîte le bilan y est calculé. Les résultats montrent que les flux de chaleur et le mélange vertical dominent le bilan aux échelles saisonnière et inter annuelle. Ce mélange vertical, calculé par résidu, est comparé avec les données indépendantes de turbulence océanique (Dengler et al., 2010 ; Rhein et al., 2010) collectées lors des campagnes EGEE/AMMA en 2005-2007. Les résultats montrent que le résidu se compare très bien avec ces données indépendantes en terme de variabilité spatiale et temporelle. Le mélange vertical est très fort dans la région sauf dans les boîtes au sud de l'AEE et sa variabilité est largement pilotée par les flux de flottabilité et la tension du vent. En regard de ces résultats avec ceux obtenus sur le cycle diurne, on peut dire que dans l'AEE, la variabilité spatio-temporelle des paramètres de la couche de mélange est principalement pilotée à toutes les échelles par les flux de chaleur et les processus de sub-surface.This work is part of the African Monsoon Multidisciplinary Analysis (AMMA) program. It focuses on the air-sea interactions in the Gulf of Guinea (GG) at diurnal to interannual timescales based on observations and numerical models. This coupling is the leading process that modulates the West African Monsoon onset which in turn impacts on the seasonal rainfall in the Western African countries. We have shown that the oceanic mixed-layer parameters in the GG are mainly driven, at diurnal timescale, by both the surface heat fluxes and the subsurface processes (entrainment, vertical turbulent mixing). We have also evidenced that from a simple parameterization of the Turbulent Kinetic Energy (TKE) based on a 1.5 closure moment, it is possible to retrieve the turbulence dissipation in this region. In order quantify the potential role of the wind stress in the oceanic mixed-layer variability, we utilize a dynamical linear model forced by wind stress anomalies and where in the equation governing the sea surface variability, the surface heat fluxes are ignored. The results show that near the equator (3°S-3°N), the signal is retrieved; however away from this band (3°S-3°N), the amplitude of the oceanic mixed-layer parameters is largely underestimated meaning that the wind stress is not the leading process in these latitudes. Mixed-layer heat budgets from Argo profiles allow identifying both the role of surface heat fluxes and the vertical mixing in the GG. The GG is subdivided into boxes with respect to the dynamic and the thermodynamic and in each box the budget is estimated. The results show that the surface heat fluxes and the vertical mixing term dominate the budget at all timescales. This vertical mixing, estimated as a residual in this study, is compared with independent turbulence data measured during EGEE/AMMA campaigns during 2005-2007 (Marcus Dengler, personal communication; Rhein et al., 2010). The results show that the vertical mixing compares very well with the independent turbulence data in terms of spatial and temporal variability. This vertical mixing is strong in the region except in the South of the GG and its seasonal cycle is largely modulated by the buoyancy heat flux and the wind stress. These results and those obtain from the diurnal cycle allow to stress that the oceanic mixed-layer in the GG s largely driven at all timescales by the surface heat fluxes and the subsurface processes
