Effects of Propofol on Glutamate-Induced Calcium Mobilization in Presynaptic Boutons of Rat Hippocampal Neurons

Recent reports have suggested that various general anesthetics affect presynaptic processes in the central nervous system. However, characterizations of the influence of intravenous anesthetics on neurotransmitter release from presynaptic nerve terminals (boutons) are insufficient. Because the presynaptic calcium concentration ([Ca2+]pre) regulates neurotransmitter release, we investigate the effects of the intravenous anesthetic propofol on neurotransmitter release by measuring [Ca2+]pre in the presynaptic boutons of individual dissociated hippocampal neurons. Brain slices were prepared from Sprague–Dawley rats (10 - 14 days of age). The hippocampal CA1 area was isolated with a fire-polished glass pipette, which vibrated horizontally to dissociate hippocampal CA1 neurons along with their attached presynaptic boutons. Presynaptic boutons were visualized under a confocal laser scanning microscope after staining with FM1-43 dye, and [Ca2+]pre was measured using fluo-3 AM dye. Glutamate (3 – 100 μM) administration increased [Ca2+]pre in Ca2+- containing external solution in a concentration-dependent manner. Propofol (3 – 30 μM) dose-dependently suppressed this glutamate (30 μM)-induced increase in [Ca2+]pre in boutons attached to dendrites, but not to the soma or base of the dendritic tree. The large majority of excitatory synapses on CA1 neurons are located on dendritic spines;therefore, propofol may affect glutamate-induced Ca2+ mobilization in excitatory, but not inhibitory, presynaptic boutons. Propofol may possibly have some effect on glutamate-regulated neurotransmitter release from excitatory presynaptic nerve terminals through inhibiting the increase in [Ca2+]pre induced by glutamate.

Hepatitis B virus reactivation with a rituximab-containing regimen

Rituximab is currently used not only in the treatment of B-cell lymphoma but also for various other diseases, including autoimmune diseases, post-transplant graft vs host disease, and rejection following kidney transplants. Due to rituximab's widespread use, great progress has been made regarding research into complications that arise from its use, one of the most serious being the reactivation of hepatitis B virus(HBV), and efforts continue to establish guidelines for preventive treatment against this occurrence. This report discusses preventive measures against rituximab-induced HBV reactivation and future objectives.

Unexpected Airway Obstruction Caused by Bilateral Hypoglossal Nerve Palsy Following Second Radical Neck Dissection

A 67-year-old woman underwent right radical neck dissection for cervical lymph node metastasis from maxillary gingival carcinoma. Two months later, metastasis in the left superior internal jugular lymph nodes were discovered, and left radical neck dissection was performed. Postoperatively, airway obstruction occurred despite performing extubation after confirming that the patient had fully recovered from anesthesia. Bilateral hypoglossal nerve palsy was diagnosed and the patient was reintubated. After extubation on the following day, airway obstruction was relieved, but slurred speech and impaired swallowing were persistent. In view of this, hypoglossal nerve function should be examined before the second radical neck dissection on the contralateral side.