Mandatory reporting legislation in Canada: improving systems for patient safety?

Patient safety is a complex systems issue. In this study, we used a scoping review of peer-reviewed literature and a case study of provincial and territorial legislation in Canada to explore the influence of mandatory reporting legislation on patient safety outcomes in hospital settings. We drew from a conceptual model that examines the components of mandatory reporting legislation that must be in place as a part of a systems governance approach to patient safety and used this model to frame our results. Our results suggest that mandatory reporting legislation across Canada is generally designed to gather information about - rather than respond to and prevent - patient safety incidents. Overall, we found limited evidence of impact of mandatory reporting legislation on patient safety outcomes. Although legislation is one lever among many to improve patient safety outcomes, there are nonetheless several considerations for patient safety legislation to assist in broader system improvement efforts in Canada and elsewhere. Legislative frameworks may be enhanced by strengthening learning systems, accountability mechanisms and patient safety culture.

Elevated incubation temperature improves later-life swimming endurance in juvenile Chinook salmon, Oncorhynchus tshawytscha.

The effect of incubation and rearing temperature on muscle development and swimming endurance under a high-intensity swimming test was investigated in juvenile Chinook salmon (Oncorhynchus tshawytscha) in a hatchery experiment. After controlling for the effects of fork length (LF ) and parental identity, times to fatigue of fish were higher when fish were incubated or reared at warmer temperatures. Significant differences among combinations of pre- and post-emergence temperatures conformed to 15-15°C > 15-9°C > 9-9°C > 7-9°C > 7-7°C in 2011 when swimming tests were conducted at 300 accumulated temperature units post-emergence and 15-9°C > (7-9°C = 7-7°C) in 2012 when swimming tests were conducted at an LF of c. 40 mm. The combination of pre- and post-emergence temperatures also affected the number and size of muscle fibres, with differences among temperature treatments in mean fibre cross-sectional area persisting after controlling for LF and parental effects. Nonetheless, neither fibre number nor fibre size accounted for significant variation in swimming endurance. Thus, thermal carryover effects on swimming endurance were not mediated by thermal imprinting of muscle structure. This is the first study to test how temperature, body size and muscle structure interact to affect swimming endurance during early development in salmon.

Bardet Biedl syndrome in South Africa: A single founder mutation.

BACKGROUND: Bardet Biedl syndrome (BBS) is a multisystem disorder characterised by obesity, polydactyly, intellectual disability and loss of vision due to a progressive retinopathy. Although typically a highly heterogeneous autosomal recessive disease, homozygosity for single mutation in BBS 10 has been identified in a significant number of affected individuals tested in South Africa (SA). Objectives. To delineate the ethnic distribution and clinical phenotype in a cohort of SA BBS patients with the K243IfsX15 mutation in BBS 10 and discuss the implications for genetic testing of and counselling for this disorder in SA. METHOD: This was a descriptive cross-sectional study collating clinical and laboratory data retrospectively in a genetically homogenous subgroup of BBS patients from SA. RESULTS: A total of 76 patients from 74 families were tested. Homozygosity for the K243IfsX15 BBS 10 mutation was found in 50 families (67%) and heterozygosity for the same mutation in an additional two affected individuals. With the exception of one patient of mixed ancestry, all were black South Africans from different language groups. This is in keeping with the observation that BBS is more common in this ethnic group compared with white and coloured patients in SA, first made by Prof. Beighton nearly 3 decades ago. A subset of 15 patients available for detailed phenotyping confirmed consistency with well-described features of the disorder, with some overlap with other ciliopathies. The onset of visual impairment was early in our cohort, before the age of 8 years, cognitive impairment was significant, and renal and cardiac abnormalities were infrequently encountered. Conclusion. The high frequency of homozygosity for a single mutation in an ethnic subset of the SA population is strongly suggestive of a founder effect. This has allowed establishment of a diagnostic test with a high yield in our local population. Better understanding of the phenotype will improve earlier recognition of the disorder to allow for appropriate intervention. Testing can confirm but not negate a clinical diagnosis, and can permit carrier and prenatal testing in informative families.

A non-electrolyte haemolysis assay for diagnosis and prognosis of sickle cell disease.

Abstract Red blood cells (RBCs) from patients with sickle cell disease (SCD) lyse in deoxygenated isosmotic non-electrolyte solutions. Haemolysis has features which suggest that it is linked to activation of the pathway termed Psickle. This pathway is usually described as a non-specific cationic conductance activated by deoxygenation, HbS polymerisation and RBC sickling. The current work addresses the hypothesis that this haemolysis will provide a novel diagnostic and prognostic test for SCD, dependent on the altered properties of the RBC membrane resulting from HbS polymerisation. A simple test represented by this haemolysis assay would be useful especially in less affluent deprived areas of the world where SCD is most prevalent. RBCs from HbSS and most HbSC individuals showed progressive lysis in deoxygenated isosmotic sucrose solution at pH 7.4 to a level greater than that observed with RBCs from HbAS or HbAA individuals. Cytochalasin B prevented haemolysis. Haemolysis was temperature- and pH-dependent. It required near physiological temperatures to occur in deoxygenated sucrose solutions at pH 7.4. At pH 6, haemolysis occurred even in oxygenated samples. Haemolysis was reduced in patients on long-term (>5 months) hydroxyurea treatment. Several manoeuvres which stabilise soluble HbS (aromatic aldehydes o-vanillin or 5-hydroxymethyl, and urea) reduced haemolysis, an effect not due to increased oxygen affinity. Conditions designed to elicit HbS polymerisation in cells from sickle trait patients (deoxygenated hyperosmotic sucrose solutions at pH 6) supported their haemolysis. These findings are consistent with haemolysis requiring HbS polymerisation and support the hypothesis that this may be used as a test for SCD.

Emergency department staff knowledge of massive transfusion for trauma: the need for an evidence based protocol.

INTRODUCTION: Uncontrolled haemorrhage is the leading cause of potentially reversible early in-hospital death following trauma. Approximately 25% of trauma patients arriving in the emergency department have evidence of early coagulopathy. It is vital that staff within the emergency department understand the basic pathophysiological consequences of massive blood loss in trauma and are familiar with when and how to administer blood and specific blood components in trauma resuscitation. METHODS: A structured questionnaire designed to test knowledge of the use of blood and blood components in trauma resuscitation was distributed to the emergency physicians attending a regional conference in the South West of England. The questionnaire consisted of 16 questions, both multiple choice and short answer format, referenced via Medline. RESULTS: 32/32 questionnaires distributed were completed and returned. Massive transfusion protocols existed in 4/11 hospitals surveyed. 5/32 doctors were able to define the term 'massive transfusion' while 9/32, 6/32 and 3/32 were consistent with current guidelines in their prescription of platelets, fresh frozen plasma, and cryoprecipitate. 20/32 were consistent with current guidelines in identifying optimal haemoglobin levels. When asked more specifically about blood component therapy, 18/32 correctly identified target fibrinogen levels, 27/32 knew that fibrinogen is a component of fresh frozen plasma or cryoprecipitate and 1/32 correctly identified that fibrinogen is a component of both. 10/32 identified indications for beriplex and 5/32 doctors correctly identified indications for the use of recombinant factor VIIa. 20/32 doctors guessed >50% of the answers and the remaining 12/32 guessed 50%. CONCLUSIONS: The survey found that emergency physicians lacked core knowledge about the use of blood and blood component therapy in the context of massive haemorrhage following trauma. Doctors were unaware of how to prevent and treat early coagulopathy. Educational resources specifically for use by emergency physicians are limited on this topic. The use of massive transfusion protocols--that standardised blood component therapy is automatically delivered at specific points within resuscitation--would not only guide doctors, but be a clear step towards minimising the complications associated with massive transfusion.

Carnitine palmitoyl transferase activity and whole muscle oxidation rates vary with fatty acid substrate in avian flight muscles.

Birds primarily fuel migratory flights with fat, and the composition of that fat has the potential to affect overall lipid oxidation rates. We measured the whole muscle lipid oxidation rates in extensor digitorum communis muscles from white-throated sparrows (Zonotrichia albicollis Gmelin) incubated for 20 min at 20°C with radiolabeled stearate (18:0), oleate (18:1ω9), or linoleate (18:2ω6). Lipid oxidation rates were ~40% higher with linoleate than oleate (oleate: 36 ± 8.54 µmol CO(2) g(-1) h(-1)), and ~75% lower with stearate compared with oleate, indicating that maximal lipid oxidation rates can indeed be affected by the type of fatty acid supplied to the muscle. Additionally, we investigated the activity of the mitochondrial fatty acid transport-associated enzyme carnitine palmitoyl transferase (CPT) in pectoralis muscles of 5 bird species (Zonotrichia albicollis, Philomachus pugnax, Sturnus vulgaris, Taeniopygia guttata, Passer domesticus). Activity was measured in homogenized samples using various fatty acyl-CoA substrates (16:0, 16:1, 18:0, 18:1ω9, 18:2ω6, 18:3ω3, 18:3ω6, 20:0, 20:4ω6, 22:6ω3) in a spectrophotometric assay. CPT activity increased with the degree of unsaturation and decreased with chain length. CPT activity did not differ between ω3 and ω6 isomers of 18:3, nor was the pattern of CPT substrate preference different between captive white-throated sparrows in a migratory (i.e., displaying Zugunruhe) or non-migratory state. These findings can explain previously observed differences in peak performance induced by dietary fat composition and suggest that lipid supply is limiting to maximal exercise performance in birds.

Co-Infection of cattle with Fasciola hepatica and Mycobacterium bovis- immunological consequences.

Fasciola hepatica, the liver fluke, is a common parasite of cattle in much of the world. Previously, we have shown that cattle infected with F. hepatica have altered responsiveness (delayed type hypersensitivity reaction and cytokine responses) to M. bovis BCG infection. We hypothesized that co-infection with F. hepatica would, likewise, alter the immune response of cattle to virulent M. bovis infection, with possible implications for disease diagnosis and disease progression. Our previous work with F. hepatica/M. bovis BCG-infected cattle demonstrated a reduction in interferon (IFN)-gamma responsiveness in co-infected animals. Similar findings are reported here with virulent M. bovis following aerosol infection. The epidemiological significance of these findings, also, require exploration, particularly in view of the considerable resources devoted to the diagnosis and eradication of bovine tuberculosis, and the high prevalence of F. hepatica infection in areas where eradication has proved difficult.

Production of a specific extracellular inhibitor of TRPM3 channels.

BACKGROUND AND PURPOSE: Isoform-specific ion channel blockers are useful for target validation in drug discovery and can provide the basis for new therapeutic agents and aid in determination of physiological functions of ion channels. The aim of this study was to generate a specific blocker of human TRPM3 channels as a tool to help investigations of this member of the TRP cationic channel family. EXPERIMENTAL APPROACH: A polyclonal antibody (TM3E3) was made to a conserved peptide of the third extracellular (E3) loop of TRPM3 and tested for binding and functional effect. Studies of channel activity were made by whole-cell planar patch-clamp and fura-2 intracellular Ca(2+) measurement. KEY RESULTS: Ionic current mediated by TRPM3 was inhibited partially by TM3E3 over a period of 5-10 min. Ca(2+) entry in TRPM3-expressing cells was also partially inhibited by TM3E3 in a peptide-specific manner and independently of the type of agonist used to activate TRPM3. TM3E3 had no effect on TRPC5, TRPV4, TRPM2 or an endogenous ATP response. CONCLUSIONS AND IMPLICATIONS: The data show the successful development of a specific TRPM3 inhibitor and give further confidence in E3 targeting as an approach to producing isoform-specific ion channel blockers.

Modulation of TRPC5 cation channels by halothane, chloroform and propofol.

BACKGROUND AND PURPOSE: TRPC5 is a mammalian homologue of the Drosophila Transient Receptor Potential (TRP) channel and has expression and functions in the cardiovascular and nervous systems. It forms a calcium-permeable cation channel that can be activated by a variety of signals including carbachol (acting at muscarinic receptors), lanthanides (e.g. Gd3+) and phospholipids (e.g. lysophosphatidylcholine: LPC). Here we report the effects of inhalational (halothane and chloroform) and intravenous (propofol) general anaesthetics upon TRPC5. EXPERIMENTAL APPROACH: Human TRPC5 channels were expressed in HEK 293 cells and studied using fura-2 and patch-clamp recording to measure intracellular calcium and membrane currents respectively at room temperature. Human TRPM2 channels were studied for comparison. KEY RESULTS: TRPC5 activation by carbachol, Gd3+ or LPC was inhibited by halothane and chloroform at > or =0.1 and 0.2 mM respectively. Neither agent inhibited TRPM2. Propofol had an initial stimulatory effect on TRPC5 (evident in patch-clamp recordings only) and an inhibitory effect at > or =10 microM. TRPM2 was not affected by propofol. Propofol inhibited activation of TRPC5 by Gd3+ but not LPC, suggesting the effect was not directly on the channel. Propofol's anti-oxidant property was not necessary for its inhibitory effect because di-isopropyl benzene, a propofol analogue that lacks the hydroxyl group, also inhibited TRPC5. CONCLUSIONS AND IMPLICATIONS: The data show the sensitivity of TRPC5 channel to general anaesthetics and suggest that some of the effects could have clinical relevance. The effects may be explained in part by the sensitivity of the channel to biophysical properties of the lipid bilayer.

c-Jun N-terminal kinase signaling regulates events associated with both health and degeneration in motoneurons.

The c-Jun N-terminal kinases (JNKs) are activated by various stimuli and are critical for neuronal development as well as for death following a stressful stimulus. Here, we have evaluated JNK activity in both healthy and dying motoneurons from developing chick embryos and found no apparent difference in overall JNK activity between the conditions, suggesting that this pathway maybe critical in both circumstances. Pharmacological inhibition of JNK in healthy motoneurons supplied with trophic support resulted in decreased mitochondrial membrane potential, neurite outgrowth, and phosphorylation of microtubule-associated protein 1B. On the other hand, in motoneurons deprived of trophic support, inhibition of JNK attenuated caspase activation, and nuclear condensation. We also examined the role of JNK's downstream substrate c-Jun in mediating these events. While c-Jun expression and phosphorylation were greater in cells supplied with trophic support as compared with those deprived, inhibition of c-Jun had no effect on nuclear condensation in dying cells or neurite outgrowth in healthy cells, suggesting that JNK's role in these events is independent of c-Jun. Together, our data underscore the dualistic nature of JNK signaling that is critical for both survival and degenerative changes in motoneurons.

Fuel use during glycogenesis in rainbow trout (Oncorhynchus mykiss Walbaum) white muscle studied in vitro.

The purpose of this study was to examine fuel used during muscle glycogenesis in rainbow trout Oncorhynchus mykiss using an in vitro muscle slice preparation to test the hypothesis that intracellular lactate is the major glycogenic substrate and the muscle relies upon extracellular substrates for oxidation. Fish were exhaustively exercised to reduce muscle glycogen content, muscle slices were taken from exhausted fish and incubated for 1 h in medium containing various substrates at physiological concentrations. 14C-labeled lactate, glycerol or palmitate was added and 14C incorporation into muscle glycogen and/or CO2 was measured. Lactate clearance in the absence of net glycogenesis suggests that when suitable oxidizable extracellular substrates were lacking, intracellular lactate was oxidized. Only muscle incubated in lactate, glycerol or palmitate synthesized glycogen, with the greatest synthesis in muscle incubated in lactate plus glycerol. The major fate of these extracellular substrates was oxidative, with lactate oxidized at rates 10 times that of palmitate and 100 times that of glycerol. Neither extracellular lactate nor glycerol contributed significantly to glycogenesis, with lactate carbon contributing less than 0.1% of the total glycogen synthesized, and glycerol less than 0.01%. There was 100 times more extracellular lactate-carbon incorporated into CO2 than into glycogen. In the presence of extracellular lactate, palmitate or glycerol, intracellular lactate was spared an oxidative fate, allowing it to serve as the primary substrate for in situ glycogenesis, with oxidation of extracellular substrates driving ATP synthesis. The primary fate of extracellular lactate is clearly oxidative, while that of intracellular, glycolytically derived lactate is glycogenic, which suggests intracellular compartmentation of lactate metabolism.

Decreases in phosphoinositide-3-kinase/Akt and extracellular signal-regulated kinase 1/2 signaling activate components of spinal motoneuron death.

Motoneuron dependence on target-derived trophic factors during development is well established, with loss of trophic support leading to the death of these cells. A complete understanding of the intracellular signal transduction machinery associated with extracellular survival signals requires the examination of individual pathways in various cellular and environmental contexts. In cells deprived of trophic support, and hence compromised for survival, phosphoinositide-3-kinase (PI3K) is decreased when compared with healthy cells supplied with trophic support. Extracellular signal-regulated kinase 1/2 (ERK1/2) signaling is dramatically decreased in deprived cells. We have examined the role of these two pathways to understand how changes in their activity regulate motoneuron survival and death. Pharmacological inhibition of PI3K attenuated motoneuron survival and was important in the regulation of Bcl-2 serine phosphorylation, limited release of cytochrome c into the cytoplasm and caspase activation. Bax translocation from cytoplasm to mitochondria was not altered when PI3K was inhibited. High levels of ERK1/2 inhibition robustly attenuated motoneuron survival in cells supplied with trophic support, whereas moderate inhibition of ERK1/2 activation had little effect. ERK1/2 inhibition in these cells decreased Bcl-2 phosphorylation and resulted in release of cytochrome c from the mitochondria. Bax translocation and caspase activation were not affected by ERK1/2 inhibition. These data reveal that changes in PI3K and ERK1/2 signaling lead to individual and overlapping effects on the cell-death machinery. Characterizing the role of these pathways is critical for a fundamental understanding of the development and degeneration of specific neuronal populations.

Hormonal regulation of glycogen metabolism in white muscle slices from rainbow trout (Oncorhynchus mykiss Walbaum).

To test the hypothesis that cortisol and epinephrine have direct regulatory roles in muscle glycogen metabolism and to determine what those roles might be, we developed an in vitro white muscle slice preparation from rainbow trout (Oncorhynchus mykiss Walbaum). In the absence of hormones, glycogen-depleted muscle slices obtained from exercised trout were capable of significant glycogen synthesis, and the amount of glycogen synthesized was inversely correlated with the initial postexercise glycogen content. When postexercise glycogen levels were <5 micromol/g, about 4.3 micromol/g of glycogen were synthesized, but when postexercise glycogen levels were >5 micromol/g, only about 1.7 micromol/g of glycogen was synthesized. This difference in the amount of glycogen synthesized was reflected in the degree of activation of glycogen synthase. Postexercise glycogen content also influenced the response of the muscle to 10(-8) M epinephrine and 10(-8) M dexamethasone (a glucocorticoid analog). At high glycogen levels (>5 micromol/g), epinephrine and dexamethasone stimulated glycogen phosphorylase activity and net glycogenolysis, whereas at low (<5 micromol/g) glycogen levels, glycogenesis and activation of glycogen synthase activity prevailed. These data clearly indicate not only is trout muscle capable of in situ glycogenesis, but the amount of glycogen synthesized is a function of initial glycogen content. Furthermore, whereas dexamethasone and epinephrine directly stimulate muscle glycogen metabolism, the net effect is dependent on initial glycogen content.

A regulatory role for cortisol in muscle glycogen metabolism in rainbow trout Oncorhynchus mykiss Walbaum.

To test the hypothesis that cortisol has a regulatory role in fish muscle glycogenesis post-exercise, rainbow trout were treated 1 h prior to exercise with either saline (control) or metyrapone (2-methyl-1, 2-di-3-pyridyl-1-propanone) to block cortisol synthesis. Following exercise (time 0), half of the metyrapone-treated fish received a single injection of cortisol, to mimic the post-exercise rise usually observed. Muscle glycogen and the relative activities of glycogen phosphorylase a (Phos a) and glycogen synthase I (GSase I), regulatory enzymes for glycogen resynthesis, were monitored 4 h post-exercise. Metyrapone treatment succeeded in blocking the post-exercise rise in plasma cortisol (17+/-2 vs 118+/-13 ng ml(-1) in controls at time 0), and cortisol injection resulted in a larger and more prolonged cortisol increase than in controls (159+/-22 vs 121+/-14 ng ml(-1) in controls at 1 h). Muscle glycogen was completely restored in the metyrapone-treated fish within 2 h after exercise (8.3+/-0.6 vs 8+/-0.7 micromol g(-1) pre-exercise), only partially restored in control fish at 4 h (5.4+/-01.4 vs 8.8+/-1.3 micromol g(-1) pre-exercise), and not at all in cortisol-treated fish (1.0+/-0.5 micromol g(-1) at 4 h). The rapid glycogen resynthesis in the metyrapone-treated fish was associated with a more rapid inactivation of Phos a and stimulation of GSase I compared to controls. In cortisol-treated fish, Phos a activity persisted throughout 4 h post-exercise; there was also a significant stimulation of GSase I activity. As a consequence of dual activation of Phos a and GSase I, glycogen cycling probably occurred, thus preventing net synthesis. This explains why the post-exercise elevation of cortisol inhibits net glycogen synthesis in trout muscle.

Implementation of provincial/territorial health goals in Canada.

During the past two decades, policy makers in most of Canada's provinces and territories developed broad population-level goal statements about desired health or health and social outcomes. The health goals development process used in each province/territory has been described in government documents and studied by a small number of researchers. However, there is a lack of published research examining the implementation and use of the health goals since they were developed. To begin to fill this gap, we conducted a study between 1998 and 2000 that examined the implementation of provincial/territorial health goals in Canada. Our findings indicate that as the 1990s drew to a close, provincial/territorial health goals were not being used explicitly by policy makers at either provincial/territorial or regional levels in most provinces in Canada to guide health policy and program development, implementation, or evaluation. Instead, the majority of health ministry and regional policy makers were employing strategic/business plans that, at best, reflected or were similar to the original provincial/territorial health goals. Moreover, even though all provinces and the NWT/Nunavut had health goals associated with broad social, economic, and physical environment health determinants, regional-level policy makers were giving priority to health care system goals over all other types of goals. We discuss our findings in relation to studies about health goals in other countries, and we suggest implications that our findings have for both future research and health policy.

Lactate efflux from sarcolemmal vesicles isolated from rainbow trout Oncorhynchus mykiss white muscle is via simple diffusion.

Lactic acid is produced as an end product of glycolysis in rainbow trout white muscle following exhaustive exercise. The metabolically produced lactic acid causes an intramuscular acidosis that must be cleared, either via net transport out of the muscle or by conversion to glycogen, thereby replenishing the muscle energy store. Trout muscle has been shown to retain lactate and utilise it as a substrate for in situ glycogen resynthesis. The giant sarcolemmal vesicle preparation was used to characterise the potential for lactate loss from white muscle of rainbow trout. Minimal lactate loss was expected due to the requirement within the intramuscular compartment of lactate for glycogen resynthesis. The sarcolemma was found to be highly resistant to lactate loss, with efflux rates approximately 500-fold lower than influx rates [0.049+/-0.006 nmol mg(-1) min(-1) (N=21) versus 26.4+/-6.3 nmol mg(-1) min(-1) (N=5), respectively, at 25 mmol l(-1) lactate concentration]. Lactate efflux was linear over the range 10-250 mmol l(-1) lactate, and greatest under conditions when intravesicular pH was lower than extravesicular pH, but was unaffected by alpha-cyano-4-hydroxycinnamate, a known inhibitor of lactate transport. These results suggest that lactate is relatively impermeant to the trout white muscle membrane and any lactate loss occurs via passive diffusion. This resistance to lactate diffusion can explain why trout muscle retains lactate post-exercise, despite transmembrane gradients that should favour net efflux.

Neuronal P2X7 receptors are targeted to presynaptic terminals in the central and peripheral nervous systems.

The ionotropic ATP receptor subunits P2X(1-6) receptors play important roles in synaptic transmission, yet the P2X(7) receptor has been reported as absent from neurons in the normal adult brain. Here we use RT-PCR to demonstrate that transcripts for the P2X(7) receptor are present in extracts from the medulla oblongata, spinal cord, and nodose ganglion. Using in situ hybridization mRNA encoding, the P2X(7) receptor was detected in numerous neurons throughout the medulla oblongata and spinal cord. Localizing the P2X(7) receptor protein with immunohistochemistry and electron microscopy revealed that it is targeted to presynaptic terminals in the CNS. Anterograde labeling of vagal afferent terminals before immunohistochemistry confirmed the presence of the receptor in excitatory terminals. Pharmacological activation of the receptor in spinal cord slices by addition of 2'- and 3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate (BzATP; 30 microm) resulted in glutamate mediated excitation of recorded neurons, blocked by P2X(7) receptor antagonists oxidized ATP (100 microm) and Brilliant Blue G (2 microm). At the neuromuscular junction (NMJ) immunohistochemistry revealed that the P2X(7) receptor was present in motor nerve terminals. Furthermore, motor nerve terminals loaded with the vital dye FM1-43 in isolated NMJ preparations destained after application of BzATP (30 microm). This BzATP evoked destaining is blocked by oxidized ATP (100 microm) and Brilliant Blue G (1 microm). This indicates that activation of the P2X(7) receptor promotes release of vesicular contents from presynaptic terminals. Such a widespread distribution and functional role suggests that the receptor may be involved in the fundamental regulation of synaptic transmission at the presynaptic site.

Coupling of voltage-dependent potassium channel inactivation and oxidoreductase active site of Kvbeta subunits.

The accessory beta subunits of voltage-dependent potassium (Kv) channels form tetramers arranged with 4-fold rotational symmetry like the membrane-integral and pore-forming alpha subunits (Gulbis, J. M., Mann, S., and MacKinnon, R. (1999) Cell. 90, 943-952). The crystal structure of the Kvbeta2 subunit shows that Kvbeta subunits are oxidoreductase enzymes containing an active site composed of conserved catalytic residues, a nicotinamide (NADPH)-cofactor, and a substrate binding site. Also, Kvbeta subunits with an N-terminal inactivating domain like Kvbeta1.1 (Rettig, J., Heinemann, S. H., Wunder, F., Lorra, C., Parcej, D. N., Dolly, O., and Pongs, O. (1994) Nature 369, 289-294) and Kvbeta3.1 (Heinemann, S. H., Rettig, J., Graack, H. R., and Pongs, O. (1996) J. Physiol. (Lond.) 493, 625-633) confer rapid N-type inactivation to otherwise non-inactivating channels. Here we show by a combination of structural modeling and electrophysiological characterization of structure-based mutations that changes in Kvbeta oxidoreductase activity may markedly influence the gating mode of Kv channels. Amino acid substitutions of the putative catalytic residues in the Kvbeta1.1 oxidoreductase active site attenuate the inactivating activity of Kvbeta1.1 in Xenopus oocytes. Conversely, mutating the substrate binding domain and/or the cofactor binding domain rescues the failure of Kvbeta3.1 to confer rapid inactivation to Kv1.5 channels in Xenopus oocytes. We propose that Kvbeta oxidoreductase activity couples Kv channel inactivation to cellular redox regulation.

The use of population health and health promotion research by health regions in Canada.

This study examined the use of population health and health promotion (PH&HP) research by health regions in Canada. An 11-item survey was faxed to 137 (of 140) health regions. Eighty-three completed questionnaires were returned (60.8%). Results indicate that while research, in general, plays more than a moderate role in the majority of participating health regions, PH&HP research is not used frequently. The most frequent uses of PH&HP research include the development of health goals and objectives, the development of programs and services, and resource allocation. Health regions most frequently obtain PH&HP research from their own staff and from government departments. University-based researchers are not a commonly used source. This study provides a descriptive overview of health regions' engagement in evidence-based decision making related to PH&HP issues, and points to a number of strategies that both health regions and researchers can employ to enhance the use of PH&HP research by health regions.