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Biomedical subjects

A Ouammou

Publications and source records attributed to A Ouammou.

13 recordsLinked to original sources
PubMed2002

A synthetic aragonite-based bioceramic: influence of process parameters on porosity and compressive strength.

We investigate the influence of process parameters such as weight fraction and particle size of pore-former, and isostatic pressure, on porosity and compressive strength of non-sintered porous calcium carbonate biomaterials compacted at high pressure in uniaxial or isostatic mode. Experiment design and results analysis are performed according to a two-level 2k factorial design method (FDM). Results indicate that only the weight fraction of pore-former (wt fpf) influences significantly the porosity and the compressive strength. The porosity P, is described by a linear function of wt fpf, and the compressive strength sigma(comp), by an exponential one. For materials compacted under uniaxial pressing: P (vol%) = 33.7 + 85.4 (wt fpf) and sigma(comp) (MPa) = 28.8e(-9.2(wt fpf)) with 0.1 < or = wt fpf < or = 0.3. For materials compacted in isostatic mode: P (vol%) = 33.9 + 82.1 (wt fpf) and sigma(comp) (MPa) = 24.0e(-7.0(wt fpf)) with 0.15 < or = wt fpf < or = 0.35. The pore-former particle size has no significant influence on both properties. The increase in isostatic pressure provides slightly lower porosity and better compressive strength. For a fixed fraction of pore-former, isostatic pressing leads to a better compressive strength than uniaxial pressing. This study indicates that, for a constant amount of pore former, the size of macropores can be adjusted to reach optimal bone-ingrowth without change in compressive strength.

Biocompatible Materials↗
PubMed1986

Cerebral aspergillosis and encephalomeningocele.

A case of massive cerebral aspergillosis complicating a frontal encephalomeningocele is reported. The etiology and pathogenesis are discussed and the diagnosis, symptoms, and treatment possibilities reviewed.

Aspergillosis↗
PubMed1984

[So-called benign intracranial hypertension and Behçet's disease].

Five cases of Behcet's disease with pseudo-tumor cerebri are reported and discussed. The authors put the emphasis on three main points : - this morbid association is not rare; - it explains the hypothesis suggested that pseudo-tumor cerebri is secondary to the alteration of intracranial venous system and CSF resorption disturbance; - the visual prognosis is poor in this entity.

Adolescent↗
PubMed1983

[Optochiasmatic diastasis in tumors with suprasellar extension and duplication of the chiasma].

The opto chiasmatic diastasis whose extreme form is a duplication of the chiasma, corresponds to a longitudinal cleavage, using the well known fasciculation of the optic fibres. It has been noticed four times in the sellar and para sellar expanding processes (two adenomas, one craniopharyngioma and one metastasis). Generally, this lesion of the chiasma goes with big tumors (grade II); it has been detected four times in frontal approaches (15%) while the rhinoseptal approach represents 85% of our cases. The diastasis of the optic fibers with tendency to form double chiasma, instead of being an exception, happens in 4% of sellars tumors. It is perfectly identified by the frontal surgical approach, but is really hard or impossible to be recognized by the rhinoseptal surgical way. The mechanisms and the prognosis of this lesion are discussed.

Adenoma, Chromophobe↗
PubMed1982

[Contribution of Doppler angiography to the study of sub-millimeter cortical arteries].

Intra operative Doppler has been already used especially during cerebral vascular malformations surgery. The systematic practice of this method, in 15 cases, for the blood flow study of the sub millimetric cortical vessels is helpful, very simple, and harmless. The investigation has been achieved by the direct application of a sterilized 8 MHZ, 5 mm Doppler probe on a small cortical artery. As the diameter has been exactly measured (0,8 mm +/- 0,2 in 15 cases) it is easy to calculate the blood flow from the recorded curve diagrams. The normal cortical flow of the sub millimetric arteries is about 2,52 cm3/mn +/- 1,16 confirming the previous data obtained with other methods of approach. The study of contused brains, points out, the disastrous effect of edema on cerebral blood flow, which before a complete arrest, looses its continuous diastolic pattern. Deep seated angiomas can be accurately located together with the flow direction in their feeding vessels. This method is also of fair interest for extra intra-crânial anastomosis, the choice of the cortical artery for bypass and its functional appreciation.

Adult↗