Intra-arterial regional anaesthesia for hand surgery with alkalinized 0.5% lignocaine

Intra-arterial regional anaesthesia (IARA) for hand surgery is an old, forgotten technique. One of the causes of low popularity may be a scalding sensation in the hand during intra-arterial injection of lignocaine, which may be caused by low pH of lignocaine's solution. In this randomized, double-blind study, normal (pH 5.2-5.3) or alkalinized (pH 7.2-7.3) preservative-free 0.5% lignocaine 1.5 mg kg-1 was injected into the radial arteries of forty adult patients to produce anaesthesia for ambulatory hand surgery. Scalding sensation in the hand during intra-arterial injection (VAS) was less pronounced with alkalinized lignocaine (P = 0.04). The time of onset and regression of analgesia was similar in both groups. Four patients in group 1 (normal lignocaine) and six patients in group 2 (alkalinized lignocaine) needed supplemental analgesia at the start of surgery (NS). Cannulation time, operating conditions, motor blockade, surgical-, and tourniquet pain scores (VAS) and patient's acceptance were similar. Three patients (two in group 1 and one in group 2) had minor systemic adverse effects after tourniquet release (NS). Nine patients in group 1 and seven in group 2 developed minor bruises after cannulation (NS). No other sequelae of intra-arterial injections were observed. We conclude that alkalinized 0.5% lignocaine was less painful on injection than normal lignocaine and should be preferred for intra-arterial anaesthesia for hand surgery.     

Time-out with children. Effects of an explanation and brief parent training on child and parent behaviors

The purpose of the present study was twofold: (a) to determine the effect of an explanation prior to or after time-out on child compliance and on child disruptive behavior during time-out and (b) to determine the effect of brief parent training in time-out on child and parent behaviors. Thirty-two mother-child pairs served as subjects and were assigned to one of the following four groups: control, time-out only, explanation prior to time-out, or explanation following time-out. Each mother-child pair was observed for one session under pretraining, training, and posttraining conditions. The results indicated that time-out significantly increased compliance but the addition of an explanation did not further alter the effectiveness of time-out. Training in the use of time-out decreased the incidence of maternal interruptions but did affect maternal responses that were not trained. Finally, following brief time-out training for noncompliance, the mothers used the procedure only 50% of the time following noncompliance.     

Elevated interleukin-12 in progressive multiple sclerosis correlates with disease activity and is normalized by pulse cyclophosphamide therapy

The technique of pulse radiolysis has been used to investigate the possibility of intramolecular charge transfer in the dipeptide histidyltyrosine, following one-electron oxidation of one of its amino acid residues. The radical anion, Br2.- was found to react with the dipeptide at pH 6.0 with a bimolecular rate constant of 2.3+/-0.2 x 10(7) dm3 mol(-1)s(-1) suggesting that it reacts very selectively with the histidine moiety. Spectral observations at, or close to the end of this reaction show only the presence of a tyrosinyl free radical (TyrO.), however, indicating that fast (>10(6) s(-1) intramolecular charge transfer has taken place between histidine radicals (His+.) and tyrosine (TyrOH). This finding was supported by the direct observation of the rate of formation of TyrO. in experiments with the free amino acids, histidine and tyrosine, under conditions where Br2.- reacted selectively with histidine. The bimolecular rate constant for the reaction between His+. and TyrOH was found to be 2.4+/-0.5 x 10(6) dm3 mol(-1)s(-1). Taken together, the results of the study indicate that His+. is a relatively strong oxidising agent where (E (His+./His) > 770 mV at pH 6.0.     

The sulphoxidation of thioanisole catalysed by lactoperoxidase and Coprinus cinereus peroxidase: evidence for an oxygen-rebound mechanism

Using both stopped-flow and conventional spectroscopy, the oxygenation of methyl phenyl sulphide by both lactoperoxidase (LPO) and Coprinus cinereus peroxidase (CiP) was monitored. Controlled continuous addition of H2O2 during turnover and monitoring the presence of native enzymes, compounds I, II and III, led to formation of the sulphoxide in high yield and enantioselectivity. Under those conditions, LPO catalysed the formation of (R) methyl phenyl sulphoxide with a yield of 85% and an enantiomeric excess (e.e.) of 80%. CiP catalysed the formation of (S) methyl phenyl sulphoxide with a yield of 84% and an e.e. of 73%. The enantioselective performance was markedly influenced by the purity of the enzymes used. Presence of compound III during turnover led to rapid inactivation of the peroxidases and, therefore, to both a lower yield of the sulphoxides and a lower enantioselectivity. Stopped-flow kinetic data show that, for both LPO and CiP, the transition of compound I to compound II depends on the concentration of the methyl phenyl sulphide, suggesting an oxygen-rebound mechanism. In line with this mechanism, a methyl phenyl sulphide radical cation was detected by EPR during turnover for LPO.     

Synthesis and bioreductive potential of a mono N-oxide derivative of the alkylating agent chlorambucil

Chlorambucil N-oxide (CHLN-O) was synthesized and evaluated for in vitro bioreductive antitumor activity. A time-dependent hypoxic differential was observed when EMT6 cells were exposed to CHLN-O in the presence of rat liver microsomes and reducing equivalents. The cytotoxicity of the N-oxide was potentiated under hypoxia, and augmented further by a combination of low pH and hypoxia. Metabolic studies were also undertaken, which utilized previously described HPLC methodology for the analysis of CHLN-O loss from biological fluids. These demonstrated the requirement for microsomal enzymes and reducing equivalents, and also illustrated the time-dependent manner of CHLN-O loss from isolated microsomal preparations.