Pathologie-biologie
-
The contribution of magnetic resonance imaging techniques to the clinical prognosis of multiple sclerosis. Magnetic resonance imaging (MRI) is a diagnostic technique with a high sensitivity for the detection of lesions, but with a poor pathological specificity. In the case of multiple sclerosis (MS), the improvement of diagnostic efficacy depends on a careful analysis of the clinical presentation and the use of increasingly stringent MRI criteria aimed at improving the specificity of the conventional MRI T2 sequences. ⋯ These new MRI techniques allow a more precise assessment of the pathological mechanisms involved in MS, such as edema, blood brain barrier break-down, demyelinisation, gliosis, cellular infiltration and axonal loss; they provide a better means of establishing the correlation between clinical impact and the destructive nature of the MS lesion. The importance of axonal loss has recently been confirmed in MS by analyzing MRI spectroscopic and neuropathological findings. In addition to magnetization transfer imaging, MR diffusion imaging and functional MRI are being intensively studied in order to assess their contribution to the study of reversibility of the degenerative process.
-
In multiple sclerosis (MS), one of the most frequent demyelinating diseases in man, remyelination of demyelinating lesions exists but is often incomplete. Also reported in experimental models of demyelination, this phenomenom confirms the regenerating potential of the demyelinated central nervous system (CNS) and, in particular, the existence of an endogenous mechanism of oligodendrocyte renewal. Failure in efficient remyelination could result from exhaustion of the pool of remyelinating cells, loss of axons and absence of a permissive environment for remyelination. ⋯ Although restricted to particular sites of the CNS, these multipotent cells, which maintain the capacity to self-renew and to migrate throughout adulthood, could constitute a powerful source of remyelinating cells. The study of the mechanisms of proliferation, migration and differentiation of these cells in response to demyelination should allow the definition of new strategies to promote endogenous remyelination and develop therapeutic approaches for demyelinating diseases such as MS. This goal is an appealing alternative to the transplantation of myelin-forming cells and should efficiently complement strategies aimed at reducing neuronal loss and inflammation.
-
Pathologie-biologie · May 1999
[Can one use probabilistic protocols for antibiotic therapy in intensive care units?].
Due to a large spectrum, empiric antibiotics treatments participate to the increase in bacterial resistance. In order to improve its indications, the implementation of therapeutic guidelines in an ICU was studied. ⋯ The mean duration of empiric antibiotics administration was 3.2 days. It was concluded that it was possible to use guidelines of empiric antibiotic in an intensive care unit.
-
Mechanical complications of implanted venous access devices are more common than suggested by the literature. Among them, the most severe is catheter embolism, which is due primarily to costoclavicular pinch-off syndrome (POS). POS occurs mainly after infraclavicular approach of the subclavian vein, the incidence being 8/1000 in our experience. ⋯ Thrombo-embolism can also result from secondary migration into a vein adjacent of a catheter that was properly positioned initially. This complication can be produced by forceful injections or by intrathoracic pressure changes generated by coughing or intrathoracic disorders. Clinicians should watch carefully for the evidence of central venous line dysfunction that usually accompanies these complications.
-
The management of adults with sickle cell disease should be geared to the profile of the disease in adulthood. The chronic hemolytic anemia impacts everyday activities. Paroxysmal complications include painful vasoocclusive crises, acute chest syndrome, priapism, and infections. ⋯ Osteonecrosis of the hip can result in functional impairment. Pregnancy and anesthesia require special precautions. A multifaceted personalized management program, if possible at a sickle cell disease center working closely with other health care providers and social workers, offers the best hope for providing ever-increasing gains in quality of life for sickle cell disease patients.