Objective: To assess the effect of a multifaceted hand hygiene culture‐change program on health care worker behaviour, and to reduce the burden of nosocomial methicillin‐resistant Staphylococcus aureus (MRSA) infections. Design and setting: Timetabled introduction of interventions (alcohol/chlorhexidine hand hygiene solution [ACHRS], improved cleaning of shared ward equipment, targeted patient decolonisation, comprehensive “culture change” package) to five clinical areas of a large university teaching hospital that had high levels of MRSA. Main outcome measures: Health care worker hand hygiene compliance; volume of ACHRS used; prevalence of patient and health care worker MRSA colonisation; environmental MRSA contamination; rates of clinical MRSA infection; and rates of laboratory detection of ESBL‐producing Escherichia coli and Klebsiella spp. Results: In study wards, health care worker hand hygiene compliance improved from a pre‐intervention mean of 21% (95% CI, 20.3%–22.9%) to 42% (95% CI, 40.2%–43.8%) 12 months post‐intervention (P < 0.001). ACHRS use increased from 5.7 to 28.6 L/1000 bed‐days. No change was observed in patient MRSA colonisation or environmental colonisation/contamination, and, except in the intensive care unit, colonisation of health care workers was unchanged. Thirty‐six months post‐intervention, there had been significant reductions in hospital‐wide rates of total clinical MRSA isolates (40% reduction; P < 0.001), patient‐episodes of MRSA bacteraemia (57% reduction; P = 0.01), and clinical isolates of ESBL‐producing E. coli and Klebsiella spp (90% reduction; P < 0.001). Conclusions: Introduction of ACHRS and a detailed culture‐change program was effective in improving hand hygiene compliance and reducing nosocomial MRSA infections, despite high‐level MRSA endemicity.

We have previously reported that syntaxin 1A, a component of the presynaptic SNARE complex, directly modulates N-type calcium channel gating in addition to promoting tonic G-protein inhibition of the channels, whereas syntaxin 1B affects channel gating but does not support G-protein modulation (Jarvis, S. E., and Zamponi, G. W. (2001) J. Neurosci. 21, 2939 -2948). Here, we have investigated the molecular determinants that govern the action of syntaxin 1 isoforms on N-type calcium channel function. In vitro evidence shows that both syntaxin 1 isoforms physically interact with the G-protein ␤ subunit and the synaptic protein interaction (synprint) site contained within the N-type calcium channel domain II-III linker region. Moreover, in vitro evidence suggests that distinct domains of syntaxin participate in each interaction, with the COOH-terminal SNARE domain (residues 183-230) binding to G␤ and the N-terminal (residues 1-69) binding to the synprint motif of the channel. Electrophysiological analysis of chimeric syntaxin 1A/1B constructs reveals that the variable NH 2 -terminal domains of syntaxin 1 are responsible for the differential effects of syntaxin 1A and 1B on N-type calcium channel function. Because syntaxin 1 exists in both "open" and "closed" conformations during exocytosis, we produced a constitutively open form of syntaxin 1A and found that it still promoted G-protein inhibition of the channels, but it did not affect N-type channel availability. This state dependence of the ability of syntaxin 1 to mediate N-type calcium channel availability suggests that syntaxin 1 dynamically regulates N-type channel function during various steps of exocytosis. Finally, syntaxin 1A appeared to compete with G␥ for the G␤ subunit both in vitro and under physiological conditions, suggesting that syntaxin 1A may contain a G-protein ␥ subunit-like domain.Calcium influx through N-type calcium channels is a key step in neurotransmitter release from presynaptic nerve termini (1, 2). In mammalian neurons, these channels physically associate with proteins of the presynaptic vesicle docking and release machinery, notably syntaxin 1, soluble NSF attachment protein (SNAP) 1 25, synaptotagmin, cysteine string protein, Rab3-interacting molecules (RIMs), and RIM-binding protein 2, thus localizing synaptic vesicles close to the source of extracellular calcium (3-12). The interaction of SNAP25 and syntaxin 1A or 1B with the N-type calcium channel acts as a negative feedback mechanism, such that N-type calcium channel availability is reduced in the presence of these proteins, which is reflected as a negative shift in the half-inactivation potential of the channels (13-16). We have recently shown that this effect is abolished when both syntaxin 1 and SNAP25 are present concomitantly, or following coexpression of nSec-1 (also called , and that protein kinase C-dependent phosphorylation of the channel abolishes the shift in steady state inactivation (16). Together, these findings indicate that the effects of syntaxin 1 on channel avail...

The effects of auxiliary calcium channel subunits on the expression and functional properties of high-voltage activated (HVA) calcium channels have been studied extensively in the Xenopus oocyte expression system, but are less completely characterized in a mammalian cellular environment. Here, we provide the first systematic analysis of the effects of calcium channel b and a2-d subunits on expression levels and biophysical properties of three different types (Cav1.2, Cav2.1 and Cav2.3) of HVA calcium channels expressed in tsA-201 cells. Our data show that Cav1.2 and Cav2.3 channels yield significant barium current in the absence of any auxiliary subunits. Although calcium channel b subunits were in principle capable of increasing whole cell conductance, this effect was dependent on the type of calcium channel a1 subunit, and b3 subunits altogether failed to enhance current amplitude irrespective of channel subtype. Moreover, the a2-d subunit alone is capable of increasing current amplitude of each channel type examined, and at least for members of the Cav2 channel family, appears to act synergistically with b subunits. In general agreement with previous studies, channel activation and inactivation gating was regulated both by b and by a2-d subunits. However, whereas pronounced regulation of inactivation characteristics was seen with the majority of the auxiliary subunits, effects on voltage dependence of activation were only small (< 5 mV). Overall, through a systematic approach, we have elucidated a previously underestimated role of the a2-d1 subunit with regard to current enhancement and kinetics. Moreover, the effects of each auxiliary subunit on whole cell conductance and channel gating appear to be specifically tailored to subsets of calcium channel subtypes.

We documented aggregate and comparative SSI rates among five Victorian public hospitals performing CABG surgery and defined specific independent risk factors for SSI. VICSP data offer opportunities for targeted interventions to reduce SSI following cardiac surgery.

Summary:Purpose: Cholinergic-dependent plateau potentials (PPs) are intrinsically generated conductances that can elicit ictal-type seizure activity. The aim of this study was to investigate the actions of topiramate (TPM) on the generation of PPs.Methods: We used whole-cell patch-clamp recordings from CA1 pyramidal neurons in rat hippocampal slices to examine the effects of TPM on the PPs.Results: In current-clamp mode, action potentials evoked PPs after cholinergic receptor stimulation. Therapeutically relevant concentrations of TPM (50 µM) depressed the PPs evoked by action potentials. Surprisingly, in voltage-clamp mode, we discovered that the cyclic nucleotide-gated (CNG) current that underlies PP generation (denoted as I tail ) was not depressed. However, significantly longer depolarizing voltage steps were required to elicit I tail . This suggested that the calcium entry trigger for evoking PPs was depressed by TPM and not I tail itself. TPM had no effect on calcium spikes in control conditions; however, TPM did reduce calcium spikes after cholinergic-receptor stimulation. We recently found that R-type calcium spikes are enhanced by cholinergic-receptor stimulation. Therefore we isolated Rtype calcium spikes with a cocktail containing tetrodotoxin, ω-conotoxin MVIIC, ω-conotoxin-GVIA, ω-agatoxin IVA, and nifedipine. R-type calcium spikes were significantly depressed by TPM. We also examined the effects of TPM on recombinant Ca V 2.3 calcium channels expressed in tsA-201 cells. TPM depressed currents mediated by Ca V 2.3 subunits by a hyperpolarizing shift in steady-state inactivation.Conclusions: We have found that TPM reduces ictallike activity in CA1 hippocampal neurons through a novel inhibitory action of R-type calcium channels.