Time course quantification of spastic hypertonia following spinal hemisection in rats.

Progressive changes in the muscle tone and stretch reflex after spinal cord injury (SCI) provide insight into the time-course development of spasticity. This study quantified the time-course changes of hypertonia for rats following SCI of T8 hemisection. A miniature manual stretching device measured the reactive torque via a pair of pressure sensing balloons; the angular displacement was measured via an optoelectronic device. Various stretching frequencies were tested, specifically 1/3, 1/2, 1, 3/2 and 2 Hz. The reactive torque and angular displacement were used to derive the viscous and elastic components representing the viscosity and stiffness of the rat's ankle joint. The enhanced velocity-dependent properties of spasticity were observed in the SCI hemisection rats (n=9) but not in the controls (n=9). Time-course measurements from pre-surgery to 56 days following SCI showed that the muscle tone of the hemisection rats dropped immediately after spinal shock and then gradually increased to reach a peak around 21 days postinjury (P<0.01). The muscle tone remained at least 75% of the peak value up to the end of an 8 week observation period (P<0.05). The changes of muscle tone can also be verified from the electrophysiological evaluations of electromyography (EMG) (P<0.05). In addition to conventional BBB motor behavior score, our results provided time-course quantification of the biomechanical and electrophysiological properties of muscle tone from the onset of SCI. Such data are useful for investigating progressive recovery of spinal damage in animal model and for future objective assessment of improved treatment for SCI human subjects.

A comparison of the effectiveness of dexmedetomidine versus propofol target-controlled infusion for sedation during fibreoptic nasotracheal intubation.

Fibreoptic intubation is a valuable modality for airway management. This study aimed to compare the effectiveness of dexmedetomidine vs target controlled propofol infusion in providing sedation during fibreoptic intubation. Forty patients with anticipated difficult airways and due to undergo tracheal intubation for elective surgery were enrolled and randomly allocated into the dexmedetomidine group (1.0 microg.kg(-1) over 10 min) (n = 20) or the propofol target controlled infusion group (n = 20). Intubating conditions and patient tolerance as graded by a scoring system were evaluated as primary outcomes. Intubation was successful in all patients. Satisfactory intubating conditions were found in both groups (19/20 in each group). The median (IOR [range]) comfort score was 2 (1-2 [1-4]) in the dexmedetomidine group and 3 (2-4 [2-5]) in the propofol group (p = 0.027), favouring the former. The dexmedetomidine group experienced fewer airway events and less heart rate response to intubation than the propofol group (p < 0.003 and p = 0.007, respectively). Both dexmedetomidine and propofol target-controlled infusion are effective for fibreoptic intubation. Dexmedetomidine allows better tolerance, more stable haemodynamic status and preserves a patent airway.

Establishment, characterization, virus susceptibility and transfection of cell lines from cobia, Rachycentron canadum (L.), brain and fin.

Establishment and characterization of two cobia, Rachycentron canadum, cell lines derived from cobia brain (CB) and cobia fin (CF) are described. Caudal fin and brain from juvenile cobia were dissociated for 30 and 10 min, respectively, in phosphate-buffered saline containing 0.25% trypsin at 25 degrees C. The optimal culture condition for both dissociated cells (primary cell culture) was at 28 degrees C in Leibovitz-15 medium containing 10% foetal bovine serum. The cells have been sub-cultured at a ratio of 1:2 for more than 160 passages over a period of 3 years. Origin of the cultured cells was verified by comparison of their sequences of mitochondrial cytochrome oxidase subunit I genes (cox I) with the cox 1 sequence from cobia muscle tissue. The cell lines showed polyploidy. No mycoplasma contamination was detected. Susceptibility to grouper iridovirus was observed for the CB cell line but not the CF cell line. Both cell lines expressed green fluorescent protein after being transfected with green fluorescent reporter gene driven by the cytomegalovirus promoter.

Injection pain with propofol: the effectiveness of thiopentone on induction.

One hundred and twenty-seven children aged 3-6 years were allocated to four groups. All of them received venous cannulation on the dorsum of the hand. On induction, the group L1, L2 and L3 patients received propofol 3 mg/kg mixed with lignocaine 0.15 mg/kg, 0.3 mg/kg, 0.6 mg/kg, respectively. The group T patients received thiopentone 3 mg/kg, then propofol 1.5 mg/kg mixed with lignocaine 0.075 mg/kg. Pain on injection was categorized into two-assessment items (facial expression and limbs withdrawal). The facial expression category were subdivided into none, mild (knit of brows), moderate (grimace), and severe (crying). The withdrawal of limbs was categorized into none, mild (withdrawal of hand), moderate (withdrawal of fore-arm and arm), severe (withdrawal of arm and twisting of body). Patients were monitored using an electrocardiogram, pulse oximeter, autonomic noninvasive blood pressure measuring device and capnography. The patient characteristics did not differ significantly among the four groups. Pain on injection was significantly more frequent in the group L1 patients (81%) compared with the group T (27%) patients. Increasing lignocaine dose reduced the incidence of pain graded as "moderate" or "severe" though there was no significant difference. The incidences of excitatory effect on propofol injection were reduced with increasing lignocaine dose and prior administration of thiopentone but there were no obviously differences among groups. We concluded that thiopentone reduced injection pain on propofol and should be recommended.

Anesthesia for pediatric herniorrhaphy or hydrocelectomy: comparison of propofol/ketamine and thiopentone/halothane.

Total intravenous anesthesia has recently become available for ambulatory surgery. It has the advantages of decreased air contamination from volatile anesthetics and decreased exposure of operating room personnel to volatile anesthetics. The purpose of this study was to compare the anesthetic properties of propofol/ketamine (total intravenous) anesthesia and thiopentone/halothane (intravenous and gaseous) anesthesia for herniorrhaphy or hydrocelectomy in children. Sixty children aged 2 to 7 years scheduled for herniorrhaphy or hydrocelectomy were allocated to two groups. The propofol/ketamine group (group 1) received a loading dose of intravenous propofol 3 mg/kg followed by propofol infusion 200 micrograms/kg/minute; additional bolus doses of propofol 1 mg/kg were given as needed or the infusion dose was increased or decreased by 33 micrograms/kg/minute as needed. Ketamine 1 mg/kg was administered intravenously 2 to 3 minutes before herniorrhaphy or hydrocelectomy to reinforce the analgesic and anesthetic effects of propofol. The thiopentone/halothane group (group 2) received intravenous thiopentone 6 mg/kg followed by halothane with 40% oxygen using a mask. Group 2 patients maintained spontaneous breathing with intermittent assistance and group 1 patients maintained spontaneous natural airway breathing during anesthesia. The scores on the postoperative assessment scale were higher in group 2 patients, indicating poorer anesthesia recovery characteristics, but the differences were not significant. Pain on injection was more frequent in group 1 (12/32) than in group 2 (2/28). The incidence of vomiting in group 2 (6/28) was significantly higher than in group 1 (0/32). We conclude that propofol/ketamine allows patients to maintain spontaneous natural airway breathing during anesthesia, and its analgesic and anesthetic effects are comparable to those of thiopentone/halothane. Propofol/ketamine is appropriate for pediatric herniorrhaphy and hydrocelectomy. It can be recommended for pediatric ambulatory surgery.