Optimising physiotherapy for people with lateral elbow tendinopathy - Results of a mixed-methods pilot and feasibility randomised controlled trial (OPTimisE).

BACKGROUND: The OPTimisE intervention was developed to address uncertainty regarding the most effective physiotherapy treatment strategy for people with Lateral Elbow Tendinopathy (LET). OBJECTIVES: To assess the feasibility of conducting a fully-powered randomised controlled trial (RCT) evaluating whether the OPTimisE intervention is superior to usual physiotherapy treatment for adults with LET. DESIGN: A mixed-methods multi-centred, parallel pilot and feasibility RCT, conducted in three outpatient physiotherapy departments in the UK. METHOD: Patients were independently randomised 1:1 in mixed blocks, stratified by site, to the OPTimisE intervention or usual care. Outcomes were assessed using pre-defined feasibility progression criteria. RESULTS: 50 patients were randomised (22 Female, 28 Male), mean age 48 years (range 27-75). Consent rate was 71% (50/70), fidelity to intervention 89% (16/18), attendance rate in the OPTimisE group 82% (55/67) vs 85% (56/66) in usual care, outcome measure completion 81% (39/48) at six-month follow-up. There were no related adverse events. Patients and physiotherapists reported that the OPTimisE intervention was acceptable but suggested improvements to the trial design. 49 patients were recruited from physiotherapy referrals vs one from primary care records. Outcome measure return rates were higher when completed online (74%) compared to postal questionnaire (50%). Exploratory analysis showed improvements in both groups over time. CONCLUSIONS: It is methodologically feasible to conduct a fully powered RCT comparing the clinical and cost-effectiveness of the OPTimisE intervention versus usual physiotherapy treatment. Considering the similar improvements observed in both groups, careful consideration is needed regarding the priority research question to be addressed in future research.

Exploring ionic liquids based on pyrrolidinium and imidazolium cations with low toxicity towards Escherichia coli for designing sustainable bioprocesses.

Ionic liquids (ILs) are widely applied in many bioprocesses involving microorganisms due to their unique properties. In this work, the toxicity of imidazolium and pyrrolidinium ionic liquids towards E. coli., a bacterium for which there are limited toxicity data in the literature, was determined. For its simplicity, the nephelometry method was used to estimate ionic liquid toxicity values. The influence of the cation and the alkyl chain length of the cation and anion was analysed. Pyrrolidinium cations were seen to be less toxic than imidazolium cations, while an increase in the alkyl chain length of both pyrrolidinium and imidazolium cations increased the toxicity. Among the anions studied, dimethylphosphate ([Me2PO4]) was the less toxic, while the EC50 for the ionic liquid 1-butyl-3-methylpyrrolidinium dimethylphosphate ([C1C4Pyr][Me2PO4]) was close to 200 mM. Furthermore, a dicationic ionic liquid based on imidazolium and pyrrolidinium cations was synthetized and its toxicity toward E. coli was analysed, maintaining a growth rate of 100 % in the range 0-0.76 mM. The methodology used in this work allows to easily find the less toxic ionic liquids that are biocompatible with E. coli to be used in new bioprocesses.

A New Perspective on Magnetotail Electron and Ion Divergent Flows: MMS Observations.

Fast divergent flows of electrons and ions in the magnetotail plasma sheet are conventionally interpreted as a key reconnection signature caused by the magnetic topology change at the X-line. Therefore, reversals of the x-component (V x⊥) of the plasma flow perpendicular to the magnetic field must correlate with the sign changes in the north-south component of the magnetic field (B z ). Here we present observations of the flow reversals that take place with no correlated B z reversals. We report six such events, which were measured with the high-resolution plasma and fields instruments of the Magnetospheric Multiscale mission. We found that electron flow reversals in the absence of B z reversals (a) have amplitudes of ∼1,000-2,000 km s-1 and durations of a few seconds; (b) are embedded into larger-scale ion flow reversals with enhanced ion agyrotropy; and (c) compared with conventional reconnection outflows around the electron diffusion regions (EDRs), have less (if ever) pronounced electron agyrotropy, dawnward electron flow amplitude, and electric field strength toward the neutral sheet, although their energy conversion parameters, including the Joule heating rate, are quite substantial. These results suggest that such flow reversals develop in the ion-demagnetization regions away from electron-scale current sheets, in particular the EDRs, and yet they play an important role in the energy conversion. These divergent flows are interpreted as precursors of the flow-driven reconnection onsets provided by the ion tearing or the ballooning/interchange instability.

Examen oftalmológico durante el control del niño sano en atención primaria: conocimiento y dificultades de los miembros del equipo de salud / Ophthalmology examination during well-child visits in primary care health centres: Knowledge and difficulties experienced by health workers

INTRODUCCIÓN: El examen del rojo pupilar y la estimación de la agudeza visual durante el control del niño sano (CNS) en atención primaria en salud (APS) en Chile representan la mejor oportunidad para pesquisar y tratar precozmente la enfermedad oftalmológica grave, como el retinoblastoma y la ambliopía. El examen oftalmológico forma parte obligatoria de las normas técnicas del Ministerio de Salud para el CNS, sin embargo se desconoce el nivel de conocimiento y la frecuencia con la que los profesionales de la salud realizan el examen oftalmológico durante el CNS, así como las dificultades que enfrentan para realizarlo en APS. MATERIAL Y MÉTODOS: Mediante encuestas a profesionales de la salud que realizan CNS en centros de APS del área xxx de Santiago de Chile se investigó la frecuencia con que realizan el examen oftalmológico de los niños y los problemas a los que se enfrentan para realizarlo apropiadamente. RESULTADOS: Ciento treinta y siete profesionales respondieron la encuesta, correspondiendo mayoritariamente a médicos (45,2%) y enfermeras (35,8%). El examen del rojo pupilar y la estimación de la agudeza visual se realizaba con baja frecuencia (34% y 42,3%, respectivamente), siendo las principales causas para no hacerlo la falta de implementos para realizar los exámenes (55,2% y 43,9%, respectivamente) y la falta de capacitación (29,3% y 22%, respectivamente). CONCLUSIÓN: En esta serie el examen oftalmológico se realizó infrecuentemente durante el CNS, requiriéndose mejor implementación y capacitación en el nivel de APS para mejorar la cobertura y calidad en beneficio de la salud visual de la población pediátrica de nuestro país

INTRODUCTION: The red reflex examination (RRE) and visual acuity testing (VA) is a mandatory part of the examination during the well-child visits (WCV) in primary health care centres of the public system of health in Chile. The eye examination is aimed at the early detection of severe eye diseases in children, such as retinoblastoma, congenital cataracts, and amblyopia. The knowledge and difficulties experienced by health workers in primary care health centres for evaluating the red reflex during WCV in Chile is unknown. MATERIAL AND METHODS: A survey was performed in primary community health centres of XXX Santiago de Chile. RESULTS: The WCV were mainly performed by physicians (45.2%) and nurses (35.8%). Only 34% of health workers performed the red reflex test, and 42.3% checked VA during the WCV. The main reasons for not doing it include the lack of direct ophthalmoscopes and VA charts (55.2% and 43.9%, respectively) at their centres, and not having the knowledge or skills (29.3% and 22%, respectively) to properly perform these clinical tests. CONCLUSION: In this series, the eye examination of children attending WCV was unfrequently performed. A better implementation of the health centres and training of the health workers are needed in order to improve the access and quality of the paediatric eye examination in primary health care institutions in Chile

Ophthalmology examination during well-child visits in primary care health centres: Knowledge and difficulties experienced by health workers. / Examen oftalmológico durante el control del niño sano en atención primaria: conocimiento y dificultades de los miembros del equipo de salud.

INTRODUCTION: The red reflex examination (RRE) and visual acuity testing (VA) is a mandatory part of the examination during the well-child visits (WCV) in primary health care centres of the public system of health in Chile. The eye examination is aimed at the early detection of severe eye diseases in children, such as retinoblastoma, congenital cataracts, and amblyopia. The knowledge and difficulties experienced by health workers in primary care health centres for evaluating the red reflex during WCV in Chile is unknown. MATERIAL AND METHODS: A survey was performed in primary community health centres of XXX Santiago de Chile. RESULTS: The WCV were mainly performed by physicians (45.2%) and nurses (35.8%). Only 34% of health workers performed the red reflex test, and 42.3% checked VA during the WCV. The main reasons for not doing it include the lack of direct ophthalmoscopes and VA charts (55.2% and 43.9%, respectively) at their centres, and not having the knowledge or skills (29.3% and 22%, respectively) to properly perform these clinical tests. CONCLUSION: In this series, the eye examination of children attending WCV was unfrequently performed. A better implementation of the health centres and training of the health workers are needed in order to improve the access and quality of the paediatric eye examination in primary health care institutions in Chile.

Identification of unique proteomic signatures in allergic and non-allergic skin disease.

BACKGROUND: Atopic dermatitis (AD), psoriasis (PS), and contact dermatitis (CD) are common skin diseases, characterized by barrier disruption and systemic inflammation, with unique epidermal signatures and common inflammatory pathways identified by transcriptomic profiling. This study profiled proteomic signatures in serum from subjects with AD, PS, and CD compared with healthy controls (HC). OBJECTIVE: Identify unique proteomic signatures to distinguish between inflammatory diseases with similar epidermal disruption and overlapping epithelial inflammation. METHODS: Sera from 20 subjects with moderate to severe AD, 10 subjects with CD, 12 subjects with moderate to severe PS, 10 subjects with both AD and CD, and 10 HC with no history of skin disease was analysed using high-throughput proteomic analysis that detects expression of 1129 protein targets. Protein expression was compared between disease and HC, and across diseases for statistical significance (fold change≥1.5 and false discovery rate≤0.05), to identify unique proteomic signatures for each disease. RESULTS: Complement C5A anaphylatoxin (C5A), lipopolysaccharide binding protein (LBP), C-reactive protein (CRP), ILT-4, C-C motif ligand 18 (PARC), and sialic acid-binding Ig-like lectin 14 (SIG14) were significantly modulated in all three diseases compared with HC. We identified unique signatures for AD (Immunoglobulin E (IgE), thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC)), CD (10 proteins), and PS (kynureninase (KYNU)). Proteomic profiling in subjects with both AD and CD identified additional dysregulated proteins compared with subjects with either condition alone, indicating an exacerbated inflammation reaction. CONCLUSIONS AND CLINICAL RELEVANCE: Unique sera proteomic signatures may distinguish between inflammatory skin diseases despite similar epidermal barrier disruption and epithelial inflammation. This may provide insight into disease pathogenesis, diagnosis, and therapeutic intervention in difficult-to-treat subjects.

Does modulation of the endocannabinoid system have potential therapeutic utility in cerebellar ataxia?

Cerebellar ataxias represent a spectrum of disorders which are, however, linked by common symptoms of motor incoordination and typically associated with deficiency in Purkinje cell firing activity and, often, degeneration. Cerebellar ataxias currently lack a curative agent. The endocannabinoid (eCB) system includes eCB compounds and their associated metabolic enzymes, together with cannabinoid receptors, predominantly the cannabinoid CB1 receptor (CB1 R) in the cerebellum; activation of this system in the cerebellar cortex is associated with deficits in motor coordination characteristic of ataxia, effects which can be prevented by CB1 R antagonists. Of further interest are various findings that CB1 R deficits may also induce a progressive ataxic phenotype. Together these studies suggest that motor coordination is reliant on maintaining the correct balance in eCB system signalling. Recent work also demonstrates deficient cannabinoid signalling in the mouse 'ducky(2J) ' model of ataxia. In light of these points, the potential mechanisms whereby cannabinoids may modulate the eCB system to ameliorate dysfunction associated with cerebellar ataxias are considered.

The D1 family dopamine receptor, DopR, potentiates hind leg grooming behavior in Drosophila.

Drosophila groom away debris and pathogens from the body using their legs in a stereotyped sequence of innate motor behaviors. Here, we investigated one aspect of the grooming repertoire by characterizing the D1 family dopamine receptor, DopR. Removal of DopR results in decreased hind leg grooming, as substantiated by quantitation of dye remaining on mutant and RNAi animals vs. controls and direct scoring of behavioral events. These data are also supported by pharmacological results that D1 receptor agonists fail to potentiate grooming behaviors in headless DopR flies. DopR protein is broadly expressed in the neuropil of the thoracic ganglion and overlaps with TH-positive dopaminergic neurons. Broad neuronal expression of dopamine receptor in mutant animals restored normal grooming behaviors. These data provide evidence for the role of DopR in potentiating hind leg grooming behaviors in the thoracic ganglion of adult Drosophila. This is a remarkable juxtaposition to the considerable role of D1 family dopamine receptors in rodent grooming, and future investigations of evolutionary relationships of circuitry may be warranted.

Evaluation and management of urinary tract infections in the school-aged child.

The evaluation and management of urinary tract infection in the school-aged child is an important part of primary care in the ambulatory setting. In this article, the salient features of how this condition presents to the clinician, how it is properly diagnosed and treated, and follow-up care are reviewed.

Saudi Arabia and the emergence of a novel coronavirus.

The novel coronavirus disease outbreak in Saudi Arabia in 2012 predominately affected males and those living in urban areas. Since September and October 2012, when the first 2 cases were published, a total of 15 confirmed cases have been reported. All but 2 have been linked to conuntries of the Arabian peninsula; Saudi Arabian nationals accounted for a majority, 8 in all, and only 1 case was female. Seven patients had severe pneumonia; 2 survived-1 with mild disease and 1 with significant underlying illness. Although transmission of the virus to health-care workers was suspected in Jordan's April 2012 outbreak, similar clusters have not been found in Saudi Arabia's hospitals, nor have additional cases been indentified through retrospective tracing of exposed health-care workers. Two family clusters have been identified, 1 in Riyadh and 1 in Manchester, England. A second Riyadh family cluster is being investigated.

Saudi Arabia and the emergence of a novel coronavirus

The novel coronavirus disease outbreak in Saudi Arabia in 2012 predominately affected males and those living in urban areas. Since September and October 2012, when the first 2 cases were published, a total of 15 confirmed cases have been reported. All but 2 have been linked to countries of the Arabian peninsula; Saudi Arabian nationals accounted for a majority, 8 in all, and only 1 case was female. Seven patients had severe pneumonia; 2 survived-1 with mild disease and 1 with significant underlying illness. Although transmission of the virus to health-care workers was suspected in Jordan's April 2012 outbreak, similar clusters have not been found in Saudi Arabia's hospitals, nor have additional cases been identified through retrospective tracing of exposed health-care workers. Two family clusters have been identified, 1 in Riyadh and 1 in Manchester, England. A second Riyadh family cluster is being investigated

Cannabidivarin is anticonvulsant in mouse and rat.

BACKGROUND AND PURPOSE: Phytocannabinoids in Cannabis sativa have diverse pharmacological targets extending beyond cannabinoid receptors and several exert notable anticonvulsant effects. For the first time, we investigated the anticonvulsant profile of the phytocannabinoid cannabidivarin (CBDV) in vitro and in in vivo seizure models. EXPERIMENTAL APPROACH: The effect of CBDV (1-100 µM) on epileptiform local field potentials (LFPs) induced in rat hippocampal brain slices by 4-aminopyridine (4-AP) application or Mg(2+) -free conditions was assessed by in vitro multi-electrode array recordings. Additionally, the anticonvulsant profile of CBDV (50-200 mg·kg(-1) ) in vivo was investigated in four rodent seizure models: maximal electroshock (mES) and audiogenic seizures in mice, and pentylenetetrazole (PTZ) and pilocarpine-induced seizures in rats. The effects of CBDV in combination with commonly used antiepileptic drugs on rat seizures were investigated. Finally, the motor side effect profile of CBDV was investigated using static beam and grip strength assays. KEY RESULTS: CBDV significantly attenuated status epilepticus-like epileptiform LFPs induced by 4-AP and Mg(2+) -free conditions. CBDV had significant anticonvulsant effects on the mES (≥100 mg·kg(-1) ), audiogenic (≥50 mg·kg(-1) ) and PTZ-induced seizures (≥100 mg·kg(-1) ). CBDV (200 mg·kg(-1) ) alone had no effect against pilocarpine-induced seizures, but significantly attenuated these seizures when administered with valproate or phenobarbital at this dose. CBDV had no effect on motor function. CONCLUSIONS AND IMPLICATIONS: These results indicate that CBDV is an effective anticonvulsant in a broad range of seizure models. Also it did not significantly affect normal motor function and, therefore, merits further investigation as a novel anti-epileptic in chronic epilepsy models. LINKED ARTICLES: This article is part of a themed section on Cannabinoids. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.167.issue-8.

The effect of elinogrel on high platelet reactivity during dual antiplatelet therapy and the relation to CYP2C19*2 genotype: first experience in patients.

UNLABELLED: To study the effect of a new direct acting reversible P2Y(12) inhibitor, elinogrel (PRT060128), and the relation to cytochrome P450 (CYP) polymorphisms in patients with high platelet reactivity (HPR) on standard dual antiplatelet therapy. METHODS AND RESULTS: We studied the pharmacodynamic and pharmacokinetic effects of a single 60-mg oral dose of elinogrel in 20 of 45 previously stented stable patients with HPR. We also genotyped for CYP2C19*2,3,5,17 and CYP3A5*3. Platelet reactivity fell within 4 h of dosing, the earliest time point evaluated as measured by the following assays: maximum 5 and 10 microM ADP LTA (P < 0.001 for both vs. predosing); maximum 20 microM ADP LTA (P < 0.05); VerifyNow (P < 0.001); thrombelastography (P < 0.05); VASP phosphorylation (P < 0.01); and perfusion chamber assay (P < 0.05); this was reversible within 24 h in these same assays (P = ns vs. predosing for all assays). CYP2C19*2 was present in 44% of all patients but was more frequent in HPR patients (77% vs. 16%, P = 0.0004). CONCLUSIONS: HPR is reversibly overcome by a single 60-mg oral dose of elinogrel, a drug now being investigated in a phase 2 trial. CYP2C19*2 was associated with HPR during conventional dual antiplatelet therapy.

Investigation of the effects of the novel anticonvulsant compound carisbamate (RWJ-333369) on rat piriform cortical neurones in vitro.

BACKGROUND AND PURPOSE: Carisbamate is being developed for adjuvant treatment of partial onset epilepsy. Carisbamate produces anticonvulsant effects in primary generalized, complex partial and absence-type seizure models, and exhibits neuroprotective and antiepileptogenic properties in rodent epilepsy models. Phase IIb clinical trials of carisbamate demonstrated efficacy against partial onset seizures; however, its mechanisms of action remain unknown. Here, we report the effects of carisbamate on membrane properties, evoked and spontaneous synaptic transmission and induced epileptiform discharges in layer II-III neurones in piriform cortical brain slices. EXPERIMENTAL APPROACH: Effects of carisbamate were investigated in rat piriform cortical neurones by using intracellular electrophysiological recordings. KEY RESULTS: Carisbamate (50-400 micromol x L(-1)) reversibly decreased amplitude, duration and rise-time of evoked action potentials and inhibited repetitive firing, consistent with use-dependent Na+ channel block; 150-400 micromol x L(-1) carisbamate reduced neuronal input resistance, without altering membrane potential. After microelectrode intracellular Cl(-) loading, carisbamate depolarized cells, an effect reversed by picrotoxin. Carisbamate (100-400 micromol x L(-1)) also selectively depressed lateral olfactory tract-afferent evoked excitatory synaptic transmission (opposed by picrotoxin), consistent with activation of a presynaptic Cl(-) conductance. Lidocaine (40-320 micromol x L(-1)) mimicked carisbamate, implying similar modes of action. Carisbamate (300-600 micromol x L(-1)) had no effect on spontaneous GABA(A) miniature inhibitory postsynaptic currents and at lower concentrations (50-200 micromol x L(-1)) inhibited Mg2+-free or 4-aminopyridine-induced seizure-like discharges. CONCLUSIONS AND IMPLICATIONS: Carisbamate blocked evoked action potentials use-dependently, consistent with a primary action on Na+ channels and increased Cl(-) conductances presynaptically and, under certain conditions, postsynaptically to selectively depress excitatory neurotransmission in piriform cortical layer Ia-afferent terminals.

Effects of Delta9-tetrahydrocannabivarin on [35S]GTPgammaS binding in mouse brain cerebellum and piriform cortex membranes.

BACKGROUND AND PURPOSE: We have recently shown that the phytocannabinoid Delta9-tetrahydrocannabivarin (Delta9-THCV) and the CB1 receptor antagonist AM251 increase inhibitory neurotransmission in mouse cerebellum and also exhibit anticonvulsant activity in a rat piriform cortical (PC) model of epilepsy. Possible mechanisms underlying cannabinoid actions in the CNS include CB1 receptor antagonism (by displacing endocannabinergic tone) or inverse agonism at constitutively active CB1 receptors. Here, we investigate the mode of cannabinoid action in [35S]GTPgammaS binding assays. EXPERIMENTAL APPROACH: Effects of Delta9-THCV and AM251 were tested either alone or against WIN55,212-2-induced increases in [35S]GTPgammaS binding in mouse cerebellar and PC membranes. Effects on non-CB receptor expressing CHO-D2 cell membranes were also investigated. KEY RESULTS: Delta9-THCV and AM251 both acted as potent antagonists of WIN55,212-2-induced increases in [35S]GTPgammaS binding in cerebellar and PC membranes (Delta9-THCV: pA2=7.62 and 7.44 respectively; AM251: pA2=9.93 and 9.88 respectively). At micromolar concentrations, Delta9-THCV or AM251 alone caused significant decreases in [35S]GTPgammaS binding; Delta9-THCV caused larger decreases than AM251. When applied alone in CHO-D2 membranes, Delta9-THCV and AM251 also caused concentration-related decreases in G protein activity. CONCLUSIONS AND IMPLICATIONS: Delta9-THCV and AM251 act as CB1 receptors antagonists in the cerebellum and PC, with AM251 being more potent than Delta9-THCV in both brain regions. Individually, Delta9-THCV or AM251 exhibited similar potency at CB1 receptors in the cerebellum and the PC. At micromolar concentrations, Delta9-THCV and AM251 caused a non-CB receptor-mediated depression of basal [35S]GTPgammaS binding.

The phytocannabinoid Delta(9)-tetrahydrocannabivarin modulates inhibitory neurotransmission in the cerebellum.

BACKGROUND AND PURPOSE: The phytocannabinoid Delta(9)-tetrahydrocannabivarin (Delta(9)-THCV) has been reported to exhibit a diverse pharmacology; here, we investigate functional effects of Delta(9)-THCV, extracted from Cannabis sativa, using electrophysiological techniques to define its mechanism of action in the CNS. EXPERIMENTAL APPROACH: Effects of Delta(9)-THCV and synthetic cannabinoid agents on inhibitory neurotransmission at interneurone-Purkinje cell (IN-PC) synapses were correlated with effects on spontaneous PC output using single-cell and multi-electrode array (MEA) electrophysiological recordings respectively, in mouse cerebellar brain slices in vitro. KEY RESULTS: The cannabinoid receptor agonist WIN 55,212-2 (WIN55) decreased miniature inhibitory postsynaptic current (mIPSC) frequency at IN-PC synapses. WIN55-induced inhibition was reversed by Delta(9)-THCV, and also by the CB(1) receptor antagonist AM251; Delta(9)-THCV or AM251 acted to increase mIPSC frequency beyond basal values. When applied alone, Delta(9)-THCV, AM251 or rimonabant increased mIPSC frequency. Pre-incubation with Delta(9)-THCV blocked WIN55-induced inhibition. In MEA recordings, WIN55 increased PC spike firing rate; Delta(9)-THCV and AM251 acted in the opposite direction to decrease spike firing. The effects of Delta(9)-THCV and WIN55 were attenuated by the GABA(A) receptor antagonist bicuculline methiodide. CONCLUSIONS AND IMPLICATIONS: We show for the first time that Delta(9)-THCV acts as a functional CB(1) receptor antagonist in the CNS to modulate inhibitory neurotransmission at IN-PC synapses and spontaneous PC output. Delta(9)-THCV- and AM251-induced increases in mIPSC frequency beyond basal levels were consistent with basal CB(1) receptor activity. WIN55-induced increases in PC spike firing rate were consistent with synaptic disinhibition; whilst Delta(9)-THCV- and AM251-induced decreases in spike firing suggest a mechanism of PC inhibition.

Elevated mercury concentrations in fish in lakes in the Mackenzie River Basin: the role of physical, chemical, and biological factors.

During the mid-1990s and through the early 2000s, researchers determined that elevated mercury concentrations were a common occurrence in predatory fish in many lakes in the Mackenzie River Basin (MRB), located in northern Canada. Here we present the results of studies investigating factors contributing to higher mercury concentrations in fish in many of these lakes. Twenty-two percent of lake trout, 33% of northern pike, and 50% of walleye populations had mean mercury concentrations >0.5 microg/g, the guideline for the commercial sale of fish. Higher mercury concentrations were strongly associated with the relatively old age of MRB predatory fish; mean age ranged from 7.6 to 24.9 years for the three species. In contrast, none of the lake trout sampled in eight lakes further south in northern Saskatchewan and Alberta had mean mercury concentrations >0.5 microg/g; fish also were younger (mean age 6 years for the 8 lakes). Mercury concentrations in MRB fish generally increased with fish length, age, and trophic feeding although the nature of these relationships varied with the lake. Mean length was a good predictor of mean mercury concentrations in walleye populations across the study lakes but not for whitefish, lake trout, and pike; age was a good predictor for lake trout and walleye. Mercury concentrations in water and invertebrates were similar to those observed in more southerly regions where fish do not have elevated mercury concentrations. Mercury concentrations tended to be higher in fish in smaller vs. larger lakes and as a probable consequence of higher summer epilimnion temperatures, which favour a higher net methylation rate, and higher mercury and methyl mercury concentrations in water which enter these lakes from the watershed. Increasing fishing pressures on MRB lakes may be a means of reducing mean fish age, improving growth rates, and decreasing mercury body burdens. Increased global warming may result in higher mercury concentrations in fish through increased water temperatures, a longer ice free season, and increased release of stored mercury from the watershed into these lakes.

A history of total mercury in edible muscle of fish from lakes in northern Canada.

Subsistence fishing has been an important source of food for Native People in northern Canada since prehistoric time. Measurements of the levels of mercury in edible muscle of northern fish have been undertaken for over three decades in efforts to evaluate the risks of consuming northern fish. This report summarizes the data obtained from 7974 fish of 25 species from sites distributed from the Yukon to Labrador. The most abundant species were lake trout, lake whitefish, arctic char, walleye, northern pike and burbot. The question being asked was essentially "Are the fish safe to eat?" The results were used to support decisions on fishing and consumption of fish. They were sorted in several ways, into concentration ranges corresponding to human consumption guidelines, into political jurisdictions and into types of bedrock geology. Overall walleye, northern pike and lake trout, usually exceeded the subsistence consumption guideline of 0.2 microg g-1 total mercury and often exceeded the higher guideline of 0.5 microg g-1 total mercury for commercial sales of fish. Mercury in burbot, another facultative predator, was often lower but several still exceeding a guideline. Arctic char collections were mostly from anadromous populations and these had very low levels of mercury, presumably reflecting marine food sources. Lake whitefish were among the cleanest fish examined with 69 of 81 collections falling in the lowest range. Most collections were from sites in sedimentary rock. However a few sites were in metamorphic, intrusive or volcanic rocks and these, taken together, tended to have a higher proportion of sites in the higher ranges of mercury. These results indicate a widespread problem with mercury in subsistence fisheries for predator species of fish with the problem being most problematic for Nunavut.

Application of TOF-SIMS with chemometrics to discriminate between four different yeast strains from the species Candida glabrata and Saccharomyces cerevisiae.

We present a TOF-SIMS analysis of the cell surface differences between four yeast strains from two species, Candida glabrata and Saccharomyces cerevisiae (haploid strains BY4742 and BY4741 and the derived diploid BY4743). The study assesses the suitability of TOF-SIMS analysis in combination with statistical methods (principal component analysis, Fisher's discriminant analysis, and cluster analysis) for the discrimination between the four yeast strains. We demonstrate that a combination of these statistical methods identifies 34 ions, from a total data set of 1200, which can be used to distinguish between the four yeasts. The study discusses the assignments of surface cell membrane phospholipids for the identified ions and the resulting differences in the phospholipid pattern between the four yeasts, particularly in relation to ploidy and budding pattern. The method shows that fatty acids, phosphatidylglycerols, phosphatidylethanolamines, phosphatidylserines, and phosphatidylcholines, as well as cardiolipins, are of diagnostic importance.