Both the intubating laryngeal mask airway Fastrach and the Trachlight lightwand attenuate the hemodynamic stress response to tracheal intubation compared with the Macintosh laryngoscope in hypertensive, but not in normotensive, anesthetized paralyzed patients.

No abstract

The pharyngeal and tracheal placement phases of nasotracheal intubation require fewer attempts with a silicone-based wire-reinforced tracheal tube with a hemispherical bevel than with a polyvinyl chloride-based precurved tracheal tube with a conventional diagonal bevel, but the glottic placement phase requires more attempts. Nasal morbidity is less common with the silicone tracheal tube.

Nitrous oxide and sevoflurane suppress the responses to LMA insertion in a linear and additive fashion in children.

We examined the relative effects of different doses of oral clonidine on the MAC for endotracheal intubation (MACEI) and the MAC for skin incision (MAC) in children. We studied 90 children (15 in each group) (age range 2-8 yr, weight 10-27 kg, height 89-124 cm) who received one of three preanaesthetic medications: placebo (control), oral clonidine 2 micrograms kg-1, or oral clonidine 4 micrograms kg-1 100 min before anaesthesia. Anaesthesia was induced and maintained with sevoflurane in oxygen and air without i.v. anesthetics and neuromuscular relaxants. The end-tidal sevoflurane concentration was kept constant for > or = 15 min before tracheal intubation or skin incision. MACs were determined using Dixon's 'up-and-down method'. Mean (SD) MACEIs of sevoflurane were 2.9 (0.1)%, 2.5 (0.1)% and 1.9 (0.1)% (P < 0.05), and MACs were 2.3 (0.1)%, 1.8 (0.1)% and 1.3 (0.1)% (P < 0.05), respectively, in control, clonidine 2 micrograms kg-1 and clonidine 4 micrograms kg-1 groups. The MACEIs and MACs decreased dose-dependently. The MACEI/MAC ratio (1.4) was not affected by clonidine.

The intubating laryngeal mask produces segmental movement of the cervical spine, despite manual in-line stabilization in patients with cervical spine pathology undergoing cervical spine surgery. This motion is in the opposite direction to direct laryngoscopy, suggesting that different approaches to airway management may be more appropriate depending on the nature of the cervical instability.

The awakening concentration of sevoflurane in unpremedicated children was 0.78%. Oral clonidine premedication at a dose of 2 microg/kg reduced the awakening concentration to 0.36%. However, an additional decrease in this value was not observed after the administration of the larger dose of clonidine premedication (4 microg/kg).

The striatum plays an important role in linking cortical activity to basal ganglia outputs. Group I metabotropic glutamate receptors (mGluRs) are densely expressed in the medium spiny projection neurons and may be a therapeutic target for Parkinson's disease. The group I mGluRs are known to modulate the intracellular Ca2+ signaling. To characterize Ca2+ signaling in striatal cells, spontaneous cytoplasmic Ca2+ transients were examined in acute slice preparations from transgenic mice expressing green fluorescent protein (GFP) in the astrocytes. In both the GFP-negative cells (putative-neurons) and astrocytes of the striatum, spontaneous slow and long-lasting intracellular Ca2+ transients (referred to as slow Ca2+ oscillations), which lasted up to approximately 200 s, were found. Neither the inhibition of action potentials nor ionotropic glutamate receptors blocked the slow Ca2+ oscillation. Depletion of the intracellular Ca2+ store and the blockade of inositol 1,4,5-trisphosphate receptors greatly reduced the transient rate of the slow Ca2+ oscillation, and the application of an antagonist against mGluR5 also blocked the slow Ca2+ oscillation in both putative-neurons and astrocytes. Thus, the mGluR5-inositol 1,4,5-trisphosphate signal cascade is the primary contributor to the slow Ca2+ oscillation in both putative-neurons and astrocytes. The slow Ca2+ oscillation features multicellular synchrony, and both putative-neurons and astrocytes participate in the synchronous activity. Therefore, the mGluR5-dependent slow Ca2+ oscillation may involve in the neuron-glia interaction in the striatum.