963 resultados para Proton acceptor
Resumo:
Main pharmacovigilance updates in 2011 are reviewed. Dronedarone: Serious cardio-vascular and hepatic adverse reactions for a questionable efficacy. Long-term proton pump inhibitors: A cause of hypomagnesemia. Bisphosphonates: A risk of atypical femoral fractures. Dasatinib: Cases of pulmonary arterial hypertension reported. Lenalidomide: A risk of second primary malignancies. Daptomycine: Cases of eosinophilic pneumonia reported. Tigecycline: Inferior to comparators. Drotrecogin alfa: Market withdrawal due to lack of efficacy. Nimesulide: More hepatotoxic than other NSAIDs. Topiramate: Evidence of teratogenicity (oral clefts). Valproate: Impaired cognitive development in addition to well-known teratogenicity. Antipsychotics in late pregnancy: A risk of neonatal complications.
Resumo:
Glial cells are increasingly recognized as active players that profoundly influence neuronal synaptic transmission by specialized signaling pathways. In particular, astrocytes have been shown recently to release small molecules, such as the amino acids l-glutamate and d-serine as "gliotransmitters," which directly control the efficacy of adjacent synapses. However, it is still controversial whether gliotransmitters are released from a cytosolic pool or by Ca(2+)-dependent exocytosis from secretory vesicles, i.e., by a mechanism similar to the release of synaptic vesicles in synapses. Here we report that rat cortical astrocytes contain storage vesicles that display morphological and biochemical features similar to neuronal synaptic vesicles. These vesicles share some, but not all, membrane proteins with synaptic vesicles, including the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) synaptobrevin 2, and contain both l-glutamate and d-serine. Furthermore, they show uptake of l-glutamate and d-serine that is driven by a proton electrochemical gradient. d-Serine uptake is associated with vesicle acidification and is dependent on chloride. Whereas l-serine is not transported, serine racemase, the synthesizing enzyme for d-serine, is anchored to the membrane of the vesicles, allowing local generation of d-serine. Finally, we reveal a previously unexpected mutual vesicular synergy between d-serine and l-glutamate filling in glia vesicles. We conclude that astrocytes contain vesicles capable of storing and releasing d-serine, l-glutamate, and most likely other neuromodulators in an activity-dependent manner.
Resumo:
Systemic mastocytosis is characterized by an excessive proliferation of mast cells and their accumulation in different organs. Avoidance of trigger factors leading to anaphylaxis is a general measure valid for all forms of mastocytosis. A premedication is necessary in case of surgery, anesthesia or administration of radiocontrast agents. Symptomatic treatment comprises antihistamines, anti-leukotrienes, proton pump inhibitors and topical corticosteroids. Indolent mastocytosis with refractory symptoms, the rare cases of aggressive mastocytosis with organ dysfunction and the even rarer mast cell leukemia require cytoreductive therapy. First-line agents are interferon alpha 2b and imatinib, a tyrosine kinase inhibitor. To date there is no curative treatment.