Bupivacaine-induced cellular entry of QX-314 and its contribution to differential nerve block

Background and Purpose: Selective nociceptor fibre block is achieved by introducing the cell membrane impermeant sodium channel blocker lidocaine N-ethyl bromide (QX-314) through transient receptor potential V1 (TRPV1) channels into nociceptors. We screened local anaesthetics for their capacity to activate TRP channels, and characterized the nerve block obtained by combination with QX-314.Experimental Approach: We investigated TRP channel activation in dorsal root ganglion (DRG) neurons by calcium imaging and patch-clamp recordings, and cellular QX-314 uptake by MS. To characterize nerve block, compound action potential (CAP) recordings from isolated nerves and behavioural responses were analysed.Key Results: Of the 12 compounds tested, bupivacaine was the most potent activator of ruthenium red-sensitive calcium entry in DRG neurons and activated heterologously expressed TRPA1 channels. QX-314 permeated through TRPA1 channels and accumulated intracellularly after activation of these channels. Upon sciatic injections, QX-314 markedly prolonged bupivacaine''s nociceptive block and also extended (to a lesser degree) its motor block. Bupivacaine''s blockade of C-, but not A-fibre, CAPs in sciatic nerves was extended by co-application of QX-314. Surprisingly, however, this action was the same in wild-type, TRPA1-knockout and TRPV1/TRPA1-double knockout mice, suggesting a TRP-channel independent entry pathway. Consistent with this, high doses of bupivacaine promoted a non-selective, cellular uptake of QX-314.Conclusions and Implications: Bupivacaine, combined with QX-314, produced a long-lasting sensory nerve block. This did not require QX-314 permeation through TRPA1, although bupivacaine activated these channels. Regardless of entry pathway, the greatly extended duration of block produced by QX-314 and bupivacaine may be clinically useful.     

The role of mitochondria-mediated intrinsic death pathway in gingerdione derivative I6-induced neuronal apoptosis

Neuronal death induced by I6 displayed apoptotic characteristics but the precise mechanism has not been fully elucidated. In the present studies, I6 at 24 h after intraperitoneal administration significantly decreased the density of surviving neurons and increased caspase-3 activity in frontal cortex, suggesting that peripherally administered I6 may cross BBB to induce CNS toxicity. In rat embryonic primary cortical cells, I6-induced reduction of mitochondrial viability and neuronal apoptosis was inhibited by vitamin E. In addition, I6-induced reactive oxygen species (ROS) caused the disruption of mitochondria membrane potential (MMP), the release of cytochrome c, the activation of caspase-9 and caspase-3, and cleavage of poly(ADP-ribose) polymerase (PARP), resulting in activation of mitochondrial-mediated intrinsic death pathway. Pre-treatment with antioxidant vitamin E or N-acetylcysteine (NAC) completely abolished the I6-induced generation of ROS, loss of MMP, release of cytochrome c, activation of caspase-9 and caspase-3, and cleavage of PARP. Carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP), a mitochondrial uncoupler, significantly reduced I6-induced neuronal death as well as caspase-3 activation and PARP cleavage. These results suggest that I6 induces neuronal death by promoting intracellular ROS production to cause a loss of MMP that result in release of cytochrome c and activation of mitochondria-mediated intrinsic death pathway.     

The involvement of PTEN in sleep deprivation-induced memory impairment in rats

Although the underlying mechanism is not elucidated, it has been postulated repeatedly that deprivation of sleep, particularly rapid eye movement (REM) sleep, affects learning. Here we report that memory for newly acquired information is impaired after a specific period of REM sleep deprivation (REMD). Memory retrieval-induced phosphorylation of protein kinases in the rat amygdala is abrogated by REMD that is associated with an increase in the expression of a dual protein/lipid phosphatase PTEN. REMD given before training is without effect, suggesting the lack of effect on the acquisition of memory. Intra-amygdala administration of antisense but not sense or scrambled oligonucleotides for PTEN prevents REMD-induced decrease in protein phosphorylation and impairment of fear memory. Thus, REMD interferes with the process of memory retention via the activation of PTEN.     

Truncal site and detoxifying enzyme polymorphisms significantly reduce time to presentation of further primary cutaneous basal cell carcinoma

Basal cell carcinoma (BCC) is the commonest cancer in Caucasians. Its incidence is rising and many patients develop multiple primary tumours at separate sites. Factors determining time between first primary tumour presentation and the next new primary lesion are unclear. We used Cox's proportional hazards model to study, in 856 Caucasians, the influence of tumour site, individual characteristics and polymorphism in glutathione S-transferase (GSTM1, GSTT1) and cytochrome P450 (CYP2D6, CYP1A1) loci on time to next primary tumour presentation. More than one tumour at first presentation (P <0.0001, hazard ratio 2.72) and GSTT1 null (P = 0.028, hazard ratio 1.74) were associated with decreased time to next primary tumour presentation. Significant two- factor interactions, corrected for number of tumours at presentation, were identified between a truncal tumour at first presentation and each of male gender, GSTM1 null and CYP2D6 EM (P <0.003, hazard ratios 3.09- 3.82). In each of these cases, all patients with the risk combination demonstrated further separate tumours within 5 years of first presentation. Thus, patients with a truncal tumour at first presentation, especially males and those presenting with more than one lesion have a significantly decreased time to presentation of further tumours and should receive more meticulous follow-up. Polymorphism in GSTM1 and CYP2D6 also influences the rate of new primary tumour accrual giving insights into the link between ultraviolet exposure and multiple tumour development.      

Comparative Neuropathology of Kuru with the New Variant of Creutzfeldt-Jakob Disease: Evidence for Strain of Agent Predominating Over Genotype of Host

The three major influences on the phenotype of the transmissible spongiform encephalopathies are believed to be strain of agent, route of infection and host genotype. We have compared the pathologic profiles and genotypes of the new variant of Creutzfeldt-Jakob disease (vCJD) and kuru. The comparison reveals that there are distinct lesional differences particularly in the prion protein (PrP) load and distribution as seen by immunohistochemistry. The clinico-pathologic phenotypes and the genotypes of these two diseases are sufficiently different to suggest that the strain of agent may play a greater role than any presumptive common route of peripherally acquired infection.     

Nerve sources for facial reanimation with muscle transplant in patients with unilateral facial palsy: clinical analysis of 3 techniques

Ninety-one patients with long-standing unilateral facial palsy and submitted to reanimation of the face with muscle transplant were divided into 3 nonrandomized groups: group I: 2-stage facial reanimation, cross face followed by gracilis muscle transplant, 58 patients; group II: 1-stage reanimation with latissimus dorsi muscle transplant, 11 patients (a branch of the facial nerve on the nonparalyzed side of the face was used as the nerve source for reanimation in groups I and II); group III: 1-stage reanimation with gracilis muscle transplant and neural coaptation of the respective nerve and the ipsilateral masseteric branch of the trigeminal nerve, 22 patients. No microvascular complications were observed. The average interval between surgery and initial muscle contractions was 11.1 months, 7.2 months, and 3.7 months in group I, group II, and group III, respectively. The quality (intensity and shape) of the smile, voluntary or involuntary, obtained on the reanimated side in relation to the unaffected side was considered good or excellent in 53.4%, 54.5%, and 86.3% of the patients in groups I, II, and III, respectively. In group I, the average age of the patients with excellent or good results (19.8 + 10.5 years) was significantly lower than that of the patients with fair or poor results or absence of movement (36.5 + 13.3 years). The smile was considered emotional or involuntary in 34% of the patients in group I and 45% in group II. Most of the patients in each group were only able to produce "voluntary smiles". Crossed synkinesis with lip puckering was observed in 48% of the patients in group I and 90% in group II. The results obtained with 1-stage facial reanimation with masseteric nerve were more uniform and predictable than those obtained with the other techniques evaluated in this study.     

Perioperative Quality Initiative consensus statement on intraoperative blood pressure,risk and outcomes for elective surgery

Background

Intraoperative mortality is now rare, but death within 30 days of surgery remains surprisingly common. Perioperative myocardial infarction is associated with a remarkably high mortality. There are strong associations between hypotension and myocardial injury, myocardial infarction, renal injury, and death. Perioperative arterial blood pressure management was thus the basis of a Perioperative Quality Initiative consensus-building conference held in London in July 2017.

Elevated adenosine deaminase and purine nucleoside phosphorylase activity in peripheral blood null lymphocytes from patients with acquired immune deficiency syndrome

The purine metabolic enzymes adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) are important in lymphocyte differentiation, and genetic deficiencies of either enzyme have been associated with hereditary immunodeficiency states. Both ADA and PNP activity were measured in null cell-enriched and T cell-enriched peripheral blood lymphocytes from 16 patients with the acquired immune deficiency syndrome (AIDS), seven patients with the AIDS-related symptom complex (ARC), and seven asymptomatic homosexuals. ADA activity in nmol/10(6) lymphocytes/h was significantly elevated in null lymphocytes from AIDS (161 +/- 12) as compared with 23 healthy heterosexual controls (127 +/- 8;P less than .025). PNP activity was also significantly increased in null lymphocytes from AIDS patients (96 +/- 10;P less than .005) as well as those from ARC patients (84 +/- 11:P less than .025) relative to controls (61 +/- 5). No significant differences in enzyme activity were noted in T cell-enriched cells in any group. Along with elevated enzyme activity, AIDS patients had small yet significant increases in the percentages of HLA-DR (P less than .025), terminal deoxynucleotidyl transferase (TdT) (P less than .0001), and peanut agglutinin receptor (P less than .0001) positive lymphocytes in the null fraction compared with controls. TdT-positive cells appeared morphologically as large lymphoblasts with irregular nuclei. The data imply that the cellular immune deficiency in AIDS is not a result of deficiencies in lymphocyte ADA or PNP activity, but is more likely associated with an increase in an immature and/or activated lymphocyte subset.     

Optimum use of a spacer device

Nedocromil sodium given by the Fisonair spacer should be inhaled immediately. Multiple actuations into the spacer should be avoided. Delay of 20 seconds before sampling reduced the amount of drug available for inhalation in the respirable range by 81%. Placing two actuations into the spacer reduced the amount of drug available by 47%.