Chlorogenic Acid Prevents AMPA-Mediated Excitotoxicity in Optic Nerve Oligodendrocytes Through a PKC and Caspase-Dependent Pathways

In the CNS, including the optic nerve, oligodendrocytes play a critical role in the myelination of axons. Oligodendrocytes are exceptionally sensitive to insults to the CNS, such as injury, ischemia, or inflammation, which result in the loss of oligodendrocytes and myelin and eventually secondary axon degeneration. Oligodendrocytes are sensitive to excitotoxic insults mediated by overactivation of their AMPA ionotropic glutamate receptors. Phenolic compounds, which are widely distributed in fruits and vegetables, received the great attention of scientists due to their antioxidant activities and free radical scavenging abilities. Chlorogenic acid (CGA) has been demonstrated to possess potent neuroprotective activities against oxidative stress in various cellular models and pathological conditions. Hence, CGA protect against oxidative stress and excitotoxic insults mediated by AMPA receptors and that the protective mechanisms involve free radical scavenging, Ca²⁺ handling in the cytosol, and modulating antioxidant enzyme system. CGA was associated with the protein kinase A (PKC) signaling pathways transduction. Caspases and calpains have been studied as apoptotic mediators and cell death in this model of AMPA toxicity. Inhibitors of caspases initiators, caspases 1, 8, and 9, the upstream of caspase 3 effectors, have totally abrogated the protective activity of CGA. Inhibitors of calpains also totally abrogated the protective activity of CGA. In addition, a potential role for the CGA in inhibiting Bax in oligodendrocyte cell model undergoing AMPA is inducing excitotoxic death. Our results indicate that CGA exhibits a protective potential via antioxidant and apoptosis caspases and calpains dependent against AMPA-mediated excitotoxicity, and these finding indicate that CGA is able to be a good candidate for preventive approach for neurodegenerative disorders associated with loss and damage in oligodendrocytes and AMPA-mediated excitotoxicity.     

Les lymphomes osseux primitifs au Maroc. Étude rétrospective à propos de 12 cas

Primary bone lymphomas (PBL) are rare. They account for 5% of the primary bone tumors and 1% of the whole of the lymphomas. This is a retrospective study over four years PBL cases gathered at the National Institute of Oncology in Morocco between January 2003 and December 2006. The median age was 44 years; the average time of diagnosis was 11 months. The predominant localization was the lumbar spine. Treatment was based on chemotherapy and radiotherapy. A laminectomy was conducted in the menacing spine localizations. The protocol of chemotherapy used was the CHOP. The follow-up varied, with extremes ranging from 1 month to 3 years. During this follow-up, no relapse was detected. Although the PBL are aggressive tumors, the prognosis is better than other bone tumors.     

Rheumatologic manifestations of sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown etiology. It has various clinical features. The most commonly affected organs are the lung, the lymph nodes, the eyes and the skin. Involvement of the musculoskeletal system is far less common and may be inaugural. Articular involvement is dominated by Lofgren syndrome and acute polyarthritis. Abarticular manifestations are often confounded with arthritis. Bone locations are dominated by sarcoidosis dactylitis and osteolysis. Muscular involvement is often unknown and can appear as 3 clinical features: spread form, myositique form or pseudotumoral form. Calcium balance disturbances are dominated by hypercalcemia which is often asymptomatique, but sometimes it reveal the sarcoidosis. Treatment of rheumatologic disorders often involves non steroidal antiinflammatory drugs, corticosteroids and methotrexate. Biological therapies such as the anti-TNFa and the anti-CD20 were showed to be effective in some case reports of severe and refractory disease.