Unusual presentation of parotid gland adenoid cystic carcinoma : A case presentation and literature review.

Adenoid cystic carcinoma (ACC) represents approximately 10% of all epithelial salivary neoplasms and most commonly involves the parotid gland. We report CT and MRI finding of a 38-year-old young man presented to our ENT department with 02 years history of an external auditory canal stenosis. Physical examination revealed bilateral parotid gland swelling with a complete stenosis of the left external auditory canal. Temporal bone contrast enhanced CT-SCAN revealed is an isodense enhancing mass measuring 4 cm involving posterior and inferior external auditory canal wall, and invading the superficial lobe of the homolateral parotid gland. No bone erosion was noted. MRI investigation has shown a tumor process highly suspicious of malignancy centered on the left EAC involving the superficial lobe of the homolateral parotid gland. Adenoid cystic carcinoma (ACC) of the parotid gland was the final diagnosis, after surgical biopsy and histopathological examination. The Pre-operative check-up demonstrated multiple round shape lung lesions suggestive of multiple metastases. Considering the metastatic stage of the tumor, a collegial decision to adopt a palliative treatment approach based on chemotherapy was taken by the multidisciplinary oncology board.

Implementing boundary conditions in simulations of arterial flows.

Computational hemodynamic models of the cardiovascular system are often limited to finite segments of the system and therefore need well-controlled inlet and outlet boundary conditions. Classical boundary conditions are measured total pressure or flow rate imposed at the inlet and impedances of RLR, RLC, or LR filters at the outlet. We present a new approach based on an unidirectional propagative approach (UPA) to model the inlet/outlet boundary conditions on the axisymmetric Navier-Stokes equations. This condition is equivalent to a nonreflecting boundary condition in a fluid-structure interaction model of an axisymmetric artery. First we compare the UPA to the best impedance filter (RLC). Second, we apply this approach to a physiological situation, i.e., the presence of a stented segment into a coronary artery. In that case a reflection index is defined which quantifies the amount of pressure waves reflected upon the singularity.

Validity of the local nonlinear arterial flow theory: influence of the upstream and downstream conditions.

The "local flow" theory provides a simple way to take into account the nonlinear convective terms associated with blood flow in large arteries. The assumption that blood velocity profiles vary slowly with the longitudinal coordinate allows a simple nonlinear resolution via a mathematical approximation. Although validated in vitro by its authors, this theory still needs to be verified in accordance with the range of variation of the hemodynamical parameters. This constitutes the aim of this work where we assess the validity of two models issued from this theory: the "direct model" using the pressure-gradient as an input for the calculations and the "indirect model" using the centre-line velocity. The assessment of these models is made by comparing their solutions to those of the linear theory using numerical simulations. Our main conclusion is that the indirect model has a wide range of validity while the direct one fails in the presence of a strong reflected wave.

Non-linear analysis of the arterial pulsatile flow: assessment of a model allowing a non-invasive ultrasonic functional exploration.

Ultrasonic measurements and modelling of blood flow in large vessels allows non-invasive evaluation of clinically interesting hemodynamic variables. To this aim, a non-linear mathematical model for the pulsatile arterial flow is proposed using the approximation of "local flow" theory. The model requires only measurements of instantaneous radius and centre-line blood velocity, and the knowledge of the tube distensibility to calculate blood velocity profiles, pressure gradient and wall shear stress. Evaluation of the proposed model using experimental data obtained from the literature proved that it can provide reliable results. In addition, as shown by assessing significance of various non-linear terms, results did not significantly change when a linear pressure-radius relationship was used instead of a non-linear relationship. Also, the model was found to be moderately sensitive to arterial tapering. Thus, the proposed model is suitable for a non-invasive clinical arterial exploration since it only requires three measurements which can be easily and precisely obtained in vivo using ultrasonic methods: the instantaneous radius, the centre-line velocity and the mean pulse wave velocity, this last variable characterizing the tube distensibility when assuming a linear pressure-radius relationship.

[Maternal mortality and referral maternities in Morocco: how to (re)motivate professionals?]. / Mortalité maternelle et maternités de référence au Maroc: comment (re)motiver les professionnels?

The very high rates of maternal mortality and perinatal mortality, as well as the deficiencies and dysfunctions observed in maternity hospitals, which play the role of referential maternity wards, led the Moroccan Minister of Public Health to implement a project in order to improve the quality of care of parturient women and new-borns. This project included 8 provinces in the country. The strategy chosen was "the team approach to resolving health problems", which is a learning process which leads local teams to implement and evaluate projects they have developed themselves. This pedagogical approach, which is carried out over a period of more than a year, proved itself to be very motivating and mobilising for the professionals included, despite the obstacles that were encountered. It also contributed to creating a true team spirit. Most activities planned within these projects were carried out and many indicators improved.

Deconvolution process in measurement of arterial velocity profiles via an ultrasonic pulsed Doppler velocimeter for evaluation of the wall shear rate.

A numerically based simulation of pulsed Doppler ultrasound convolution and deconvolution of theoretical hemodynamic velocity profiles yields two major conclusions on performing a deconvolution process. First, the most important parameter to be accounted for is the size of the sample volume. Second, a deconvolution process with an overestimated sample volume size is revealed by high-frequency noise on the resulting profile. A deconvolution process is presented for in vivo arterial velocity profiles, which has the advantage of being systematic and not needing experimental testing for determining the size or the shape of the sample volume. It is also independent of the observation angle. Finally, an example of an application to in vivo human velocity profiles is given. Evaluation of the wall shear rate from the corrected deconvolved profiles shows a noticeable improvement with respect to that using the directly convolved Doppler profiles.

Kinetic behaviour of pancreatic lipase in five species using emulsions and monomolecular films of synthetic glycerides.

In the absence of colipase and bile salts, using tributyrin emulsions or monomolecular films of dicaprin at low surface pressure, we observed that no significant lipase activity can be measured with Human Pancreatic Lipase (HuPL), Horse Pancreatic Lipase (HoPL) or Dog Pancreatic Lipase (DPL). Only Porcine Pancreatic Lipase (PPL) and recombinant Guinea Pig Pancreatic Lipase Related Protein of type 2 (r-GPL) hydrolyse pure tributyrin in the absence of any additive, as well as dicaprin films at low surface pressures. The former lipases may lack enzyme activity because of irreversible interfacial denaturation due to the high energy existing at the tributyrin/water interface and at the dicaprin film surface at low surface pressures. The enzyme denaturation cannot be reflected in the number of disulfide bridges, since all the pancreatic lipases tested here contain six disulfide bridges, but behaved very differently at interfaces. We propose to use the surface pressure threshold, as determined using the monomolecular technique, as a criterion for classifying lipases in terms of their sensitivity to interfacial denaturation.

A new geometric procedure for in vivo pulsed Doppler evaluation of velocity distribution inside the diametrical section of large arteries in humans.

A new geometric procedure determination of velocity profiles inside large human arteries, such as the brachial and femoral, has been developed. The procedure requires the use of two crystal element Doppler probes and a highly precise micromanipulator with three degrees of freedom. Precise positioning is needed to obtain the required high degree of parallelism between the vessel axis and the plane containing the two crystal elements. Once the appropriate degree of parallelism is achieved, a controlled translation of the probe, perpendicular to the ultrasonic beam plane, allows velocity waveforms to be recorded at sequential radial positions across the measured artery. Velocity profiles obtained with this geometric procedure depended on the type of artery investigated. The profiles measured with the geometric procedure were more symmetrical than those found using the electronic range-gated time system of reception. While the geometric and electronic methods were almost identical in determining the diameter values of the three arteries measured, the geometric procedure enabled greater accuracy for detailed analysis of velocity profiles in the peripheral large arteries in humans. Although the present methodology is not applicable in clinical practice due to prolonged data acquisition time (approximately 45 s) it is expected that future equipment improvements will reduce this time significantly.