Interlimb conditioning of lumbosacral spinally evoked motor responses after spinal cord injury.

OBJECTIVE: The importance of subcortical pathways to functional motor recovery after spinal cord injury (SCI) has been demonstrated in multiple animal models. The current study evaluated descending interlimb influence on lumbosacral motor excitability after chronic SCI in humans. METHODS: Ulnar nerve stimulation and transcutaneous electrical spinal stimulation were used in a condition-test paradigm to evaluate the presence of interlimb connections linking the cervical and lumbosacral spinal segments in non-injured (n=15) and spinal cord injured (SCI) (n=18) participants. RESULTS: Potentiation of spinally evoked motor responses (sEMRs) by ulnar nerve conditioning was observed in 7/7 SCI participants with volitional leg muscle activation, and in 6/11 SCI participants with no volitional activation. Of these six, conditioning of sEMRs was present only when the neurological level of injury was rostral to the ulnar innervation entry zones. CONCLUSIONS: Descending modulation of lumbosacral motor pools via interlimb projections may exist in SCI participants despite the absence of volitional leg muscle activation. SIGNIFICANCE: Evaluation of sub-clinical, spared pathways within the spinal cord after SCI may provide an improved understanding of both the contributions of different pathways to residual function, and the mechanisms of plasticity and functional motor recovery following rehabilitation..

Adherence of volatile propofol to various types of plastic tubing.

Propofol is an intravenous anesthetic. Currently, it is not possible to routinely measure blood concentration of the drug in real time. However, multi-capillary column ion-mobility spectrometry of exhaled gas can estimate blood propofol concentration. Unfortunately, adhesion of volatile propofol on plastic materials complicates measurements. Therefore, it is necessary to consider the extent to which volatile propofol adheres to various plastics used in sampling tubing. Perfluoralkoxy (PFA), polytetrafluorethylene (PTFE), polyurethane (PUR), silicone, and Tygon tubing were investigated in an experimental setting using a calibration gas generator (HovaCAL). Propofol gas was measured for one hour at 26 °C, 50 °C, and 90 °C tubing temperature. Test tubing segments were then flushed with N2 to quantify desorption. PUR and Tygon sample tubing absorbed all volatile propofol. The silicone tubing reached the maximum propofol concentration after 119 min which was 29 min after propofol gas exposure stopped. The use of PFA or PTFE tubing produced comparable and reasonably accurate propofol measurements. The desaturation time for the PFA was 10 min shorter at 26 °C than for PTFE. PFA tubing thus seems most suitable for measurement of volatile propofol, with PTFE as an alternative.

Retinoids for preventing the progression of cervical intra-epithelial neoplasia.

BACKGROUND: Invasive cervical carcinoma is preceded by a precancerous phase, cervical intra-epithelial neoplasia (CIN), which can be detected on cervical smears and confirmed by colposcopy and biopsy. Moderate and severe intra-epithelial neoplasia (CIN2 and CIN3) are treated mainly with surgery to prevent progression to invasive carcinoma. Medical methods of preventing the progression or inducing regression of CIN are needed. Retinoids are potent modulators of epithelial cell growth and differentiation and may have potential for the treatment of CIN. OBJECTIVES: To ascertain whether retinoids can cause regression or prevent progression of CIN. SEARCH STRATEGY: Cochrane Gynaecological Cancer Review Group's Specialised Register and Non-Trials Database, Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 2,2007),MEDLINE and EMBASE (June 2007). SELECTION CRITERIA: Randomized controlled trials (RCTs) and non-RCTs of retinoids for treating CIN in women. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data from the trials. Adverse effects information was also collected from the trials. MAIN RESULTS: Five RCTs comparing the efficacy of four different retinoids were identified. Two studies examined the effect on CIN2 and CIN3 of retinoids N-(4-hydroxyphenyl)retinamide (fenretinide) (Follen 2001) and 9-cis-retinoic acid (aliretinoin) (Alvarez 2003) given orally and two examined the effect of all-trans-retinoic acid given topically to the cervix (Meyskens 1994; Ruffin 2004). The fifth study investigated the use of 13-cis-retinoic acid (isotretinoin) given orally in HIV positive patients with CIN1 and condyloma (Robinson 2002).Four studies reported no significant effect of retinoids on the progression to higher grades of CIN, whilst the fifth did not report data on progression. In all studies retinoids had no significant effect on regression of CIN3. Two studies reported that retinoids were associated with regression of CIN2. One reported a greater complete regression of CIN2 over placebo, which was of borderline statistical significance, odds ratio(OR) = 0.5 (95% confidence interval (CI) 0.25 to 1.02). The other study reported a non-significant dose-related trend towards increased rates of complete and partial regression compared with placebo. One study reported a significantly worse outcome in women receiving retinoid, OR for regression = 6.00 (95% CI 1.00 to 35.91). In general, the retinoid medications were well tolerated. AUTHORS' CONCLUSIONS: The retinoids studied are not effective at causing regression of CIN3 but may have some effect on CIN2. The data on CIN1 is inadequate. Retinoids are not effective at preventing progression of CIN of any grade. At the doses given and duration of treatment studied, the retinoids were reasonably well-tolerated.