A systematic review and meta-analysis of environmental contaminant exposure impacts on weight loss and glucose regulation during calorie-restricted diets in preclinical studies: Persistent organic pollutants may impede glycemic control

Epidemiological evidence links chemical exposure with type 2 diabetes (T2DM) risk and prevalence. Chemical exposure may therefore also limit success of weight loss or restoration of glycemic control during calorie restricted diets. Few human studies examine this hypothesis. This systematic review and clustered meta-analysis examines preclinical evidence that exposure to anthropogenic environmental contaminants impedes weight loss and resumption of glycemic control during calorie restriction. Of five eligible papers from 212 unique citations, four used C57BL/6 mice and one used Sprague Dawley rats. In four the animals received high fat diets to induce obesity and impaired glycemic control. All examined persistent organic pollutants (POPs). Polychlorinated biphenyl (PCB) 77 exposure did not affect final mass (standardised mean difference (SMD) = -0.35 [-1.09, 0.39]; n = 5 (experiments); n = 3 (papers)), or response to insulin in insulin tolerance tests (SMD = -1.54 [-3.25, 0.16] n = 3 (experiments); n = 2 (papers)), but impaired glucose control in glucose tolerance tests (SMD = -1.30 [-1.96, -0.63]; n = 6 (experiments); n = 3 (papers)). The impaired glycemic control following perfluoro-octane sulphonic acid (PFOS) exposure and enhanced mass loss following dichlorodiphenyltrichloroethane (DDT) exposure have not been replicated. Animal studies thus suggest some chemical groups, especially PCB and PFOS, could impair glucose control management during calorie restriction, similar to conclusions from limited existing clinical studies. We discuss the research that is urgently required to inform weight management services that are now the mainstay prevention initiative for T2DM.

An emergency-department-initiated outreach program for patients with opioid use disorder is associated with an increase in agonist therapy and engagement in addictions care: a one-year cohort study

BACKGROUND

People with opioid use disorder (OUD) are high-risk for short-term mortality and morbidity. Emergency department (ED) interventions can reduce those risks, but benefits wane without ongoing community follow-up.

OBJECTIVE

To evaluate an ED-based intensive community outreach program.

METHODS

At two urban EDs between October 2019 and March 2020, we enrolled patients with OUD not currently on opioid agonist therapy (OAT) in a prospective cohort study evaluating a one-year intensive community outreach program, which provided ongoing addictions care, housing resources, and community support. We surveyed patients at intake and at scheduled outreach encounters at one, two, six, and twelve months. Follow-up surveys assessed OAT uptake, addictions care engagement, housing status, quality of life scores, illicit opioid use, and outreach helpfulness. We used descriptive statistics for each period and conducted sensitivity and subgroup analyses to account for missing data.

RESULTS

Of 84 baseline participants, 29% were female and 32% were housed, with a median age of 33. Sixty participants (71%) completed at least one follow-up survey. Survey completion rates were 37%, 38%, 39%, and 40% respectively at one, two, six, and twelve months. Participants had a median of three outreach encounters. Among respondents, OAT was 0% at enrolment and ranged from 38% to 56% at follow-up; addictions care engagement was 22% at enrolment and ranged from 65% to 81% during follow-up; and housing was 40% at enrolment and ranged from 48% to 59% during follow-up. Improvements from baseline to follow-up occurred for all time periods. OAT and engagement in care benefits were maintained in sensitivity and subgroup analyses. Respondents rated the outreach program as helpful at all time periods, CONCLUSION: An ED-initiated intensive outreach program for patients with OUD not yet on OAT was associated with a persistent increase in OAT use and engagement in care, as well as housing.

Translating the lived experience of illicit drinkers into program guidance for cannabis substitution: Experiences from the Canadian Managed Alcohol Program Study

A small but growing body of research has suggested the potential for cannabis substitution to support Managed Alcohol Program (MAP) service users to reduce acute and chronic alcohol-related harms. In 2022, researchers from the Canadian Managed Alcohol Program Study (CMAPS) noted a dearth of accessible, alcohol-specific educational resources to support service users and program staff to implement cannabis substitution pilots at several MAP sites in Canada. In this essay, we draw on over 10-years of collaboration between CMAPS, and organizations of people with lived experience (the Eastside Illicit Drinkers Group for Education (EIDGE) and SOLID Victoria) to describe our experiences co-creating cannabis education resources where none existed to support MAP sites interested in beginning to provide cannabis to participants. The research team relied on the unique lived experiences and informal cannabis-related harm reduction strategies described by EIDGE and SOLID members to create cannabis education resources that were accurate and relevant to MAP sites. EIDGE was familiar with creating peer-oriented educational resources and convened meetings and focus groups to engage peers. CMAPS research team members created standard cannabis unit equivalencies to support program delivery, and clinical advisors ensured that the stated risks and benefits of cannabis substitution, as well as tapering guidance for withdrawal management, were safe and feasible. The collaboration ultimately produced tailored client-facing and provider-facing resources. Our experience demonstrates that the lived expertise of drinkers can play an integral role in creating alcohol harm reduction informational materials, specifically those related to cannabis substitution, when combined with data from rigorous, community-based programs of research like CMAPS. We close by listing additional considerations for cannabis substitution program design for MAP settings emerging from this process of collaboration between illicit drinkers, service providers, clinicians, and researchers for consideration by other programs.

Advancing virtual primary care for people with opioid use disorder (VPC OUD): a mixed-methods study protocol

INTRODUCTION

The emergence of COVID-19 introduced a dual public health emergency in British Columbia, which was already in the fourth year of its opioid-related overdose crisis. The public health response to COVID-19 must explicitly consider the unique needs of, and impacts on, communities experiencing marginalisation including people with opioid use disorder (PWOUD). The broad move to virtual forms of primary care, for example, may result in changes to healthcare access, delivery of opioid agonist therapies or fluctuations in co-occurring health problems that are prevalent in this population. The goal of this mixed-methods study is to characterise changes to primary care access and patient outcomes following the rapid introduction of virtual care for PWOUD.

METHODS AND ANALYSIS

We will use a fully integrated mixed-methods design comprised of three components: (a) qualitative interviews with family physicians and PWOUD to document experiences with delivering and accessing virtual visits, respectively; (b) quantitative analysis of linked, population-based administrative data to describe the uptake of virtual care, its impact on access to services and downstream outcomes for PWOUD; and (c) facilitated deliberative dialogues to co-create educational resources for family physicians, PWOUD and policymakers that promote equitable access to high-quality virtual primary care for this population.

ETHICS AND DISSEMINATION

Approval for this study has been granted by Research Ethics British Columbia. We will convene PWOUD and family physicians for deliberative dialogues to co-create educational materials and policy recommendations based on our findings. We will also disseminate findings via traditional academic outputs such as conferences and peer-reviewed publications.

"COVID just kind of opened a can of whoop-ass": The rapid growth of safer supply prescribing during the pandemic documented through an environmental scan of addiction and harm reduction services in Canada

OBJECTIVES

In the context of the ongoing overdose crisis, a stark increase in toxic drug deaths from the unregulated street supply accompanied the onset of the COVID-19 pandemic. Injectable opioid agonist treatment (iOAT - hydromorphone or medical-grade heroin), tablet-based iOAT (TiOAT), and safer supply prescribing are emerging interventions used to address this crisis in Canada. Given rapid clinical guidance and policy change to enable their local adoption, our objectives were to describe the state of these interventions before the pandemic, and to document and explain changes in implementation during the early pandemic response (March-May 2020).

METHODS

Surveys and interviews with healthcare providers comprised this mixed methods national environmental scan of iOAT, TiOAT, and safer supply across Canada at two time points. Quantitative data were summarized using descriptive statistics; interview data were coded and analyzed thematically.

RESULTS

103 sites in 6 Canadian provinces included 19 iOAT, 3 TiOAT and 21 safer supply sites on March 1, 2020; 60 new safer supply sites by May 1 represented a 285% increase. Most common substances were opioids, available at all sites; most common settings were addiction treatment programs and primary care clinics, and onsite pharmacies models. 79% of safer supply services were unfunded. Diversity in service delivery models demonstrated broad adaptability. Qualitative data reinforced the COVID-19 pandemic as the driving force behind scale-up.

DISCUSSION

Data confirmed the capacity for rapid scale-up of flexible, community-based safer supply prescribing during dual public health emergencies. Geographical, client demographic, and funding gaps highlight the need to target barriers to implementation, service delivery and sustainability.

The changing landscape of pharmaceutical alternatives to the unregulated drug supply during COVID-19

Background

The dual COVID-19 and overdose emergencies amplified strain on healthcare systems tasked with responding to both. One downstream consequence of the pandemic in the USA and Canada was a surge in drug overdoses resulting from public health-restricted access to services and an increasingly toxic unregulated drug supply. This study aimed to describe changes implemented by programs prescribing pharmaceutical alternatives to the drug supply during the early stages of the COVID-19 pandemic.

Methods

An environmental scan used surveys and qualitative interviews with service providers across Canada to examine pharmaceutical alternative prescribing practices and programs before and during the pandemic. This study summarized the nature, frequency, and reasons for pandemic-driven service delivery changes using directed content analysis, counts, and thematic analysis.

Results

Eighty-two of the 103 participating sites reported 1193 unique changes in physical space (368), client protocols (347), program operations (342), ancillary services (127), and staffing (90). Four qualitative themes describing the reasons for these changes emerged, namely (1) decreasing risk of COVID-19 infection; (2) decreasing risk of overdose; (3) prioritizing acute care of COVID-19 patients; and (4) improving client access to treatment.

Conclusions

While most changes were aimed at decreasing risk of COVID-19 infection, some were found to be at odds with the measures needed to combat the overdose crisis; others met dual objectives of decreased risk of both overdose and infection. Further research should examine which changes should be kept or reversed once COVID-19-related public health measures are lifted.

"If I knew I could get that every hour instead of alcohol, I would take the cannabis": need and feasibility of cannabis substitution implementation in Canadian managed alcohol programs

Background

While there is robust evidence for strategies to reduce harms of illicit drug use, less attention has been paid to alcohol harm reduction for people experiencing severe alcohol use disorder (AUD), homelessness, and street-based illicit drinking. Managed Alcohol Programs (MAPs) provide safer and regulated sources of alcohol and other supports within a harm reduction framework. To reduce the impacts of heavy long-term alcohol use among MAP participants, cannabis substitution has been identified as a potential therapeutic tool.

Methods

To determine the feasibility of cannabis substitution, we conducted a pre-implementation mixed-methods study utilizing structured surveys and open-ended interviews. Data were collected from MAP organizational leaders (n = 7), program participants (n = 19), staff and managers (n = 17) across 6 MAPs in Canada. We used the Consolidated Framework for Implementation Research (CFIR) to inform and organize our analysis.

Results

Five themes describing feasibility of CSP implementation in MAPs were identified. The first theme describes the characteristics of potential CSP participants. Among MAP participants, 63% (n = 12) were already substituting cannabis for alcohol, most often on a weekly basis (n = 8, 42.1%), for alcohol cravings (n = 15, 78.9%,) and withdrawal (n = 10, 52.6%). Most MAP participants expressed willingness to participate in a CSP (n = 16, 84.2%). The second theme describes the characteristics of a feasible and preferred CSP model according to participants and staff. Participants preferred staff administration of dry, smoked cannabis, followed by edibles and capsules with replacement of some doses of alcohol through a partial substitution model. Themes three and four highlight organizational and contextual factors related to feasibility of implementing CSPs. MAP participants requested peer, social, and counselling supports. Staff requested education resources and enhanced clinical staffing. Critically, program staff and leaders identified that sustainable funding and inexpensive, legal, and reliable sourcing of cannabis are needed to support CSP implementation.

Conclusion

Cannabis substitution was considered feasible by all three groups and in some MAPs residents are already using cannabis. Partial substitution of cannabis for doses of alcohol was preferred. All three groups identified a need for additional supports for implementation including peer support, staff education, and counselling. Sourcing and funding cannabis were identified as primary challenges to successful CSP implementation in MAPs.

"It's Helped Me a Lot, Just Like to Stay Alive": a Qualitative Analysis of Outcomes of a Novel Hydromorphone Tablet Distribution Program in Vancouver, Canada

North America is experiencing an overdose crisis driven by fentanyl, related analogues, and fentanyl-adulterated drugs. In response, there have been increased calls for "safe supply" interventions based on the premise that providing a safer alternative (i.e., pharmaceutical drugs of known quality/quantity, non-adulterated, with user agency in consumption methods) to the street drug supply will limit people's use of fentanyl-adulterated drugs and reduce overdose events. This study examined outcomes of a hydromorphone tablet distribution program intended to prevent overdose events among people who use drugs (PWUD) at high risk of fatal overdose. Semi-structured qualitative interviews were conducted with 42 people enrolled in the hydromorphone distribution program. Additionally, over 100 h of ethnographic observation were undertaken in and around the study site. Transcripts were coded using NVivo and based on categories extracted from the interview guides and those identified during initial interviews and ethnographic fieldwork. Analysis focused on narratives around experiences with the program, focusing on program-related outcomes. Our analysis identified the following positive outcomes of being enrolled in the hydromorphone tablet distribution program: (1) reduced street drug use and overdose risk, (2) improvements to health and well-being, (3) improvements in co-management of pain, and (4) economic improvements. Our findings indicate that the hydromorphone distribution program not only is effective in responding to the current overdose crisis by reducing people's use of illicit drugs but also addresses inequities stemming from the intersection of drug use and social inequality. Safe supply programs should be further implemented and evaluated in both urban and rural setting across North America as a strategy to reduce exposure to the toxic drug supply and fatal overdose.

Service delivery models for injectable opioid agonist treatment in Canada: 2 sequential environmental scans

BACKGROUND

Injectable opioid agonist treatment (iOAT) is an emerging evidence-based option in the continuum of care for opioid use disorder in parts of Canada. Our study objective was to identify and describe iOAT programs operating during the ongoing opioid overdose crisis.

METHODS

We conducted 2 sequential environmental scans. Programs were eligible to participate if they were in operation as of Sept. 1, 2018, and Mar. 1, 2019. Information was collected over 2-3 months for each scan (September-October 2018, March-May 2019). Programs that participated in the first scan and newly established programs were invited to participate in the second scan. The scans included questions about location, service delivery model, clinical and operational characteristics, numbers and demographic characteristics of clients, and program barriers and facilitators. Descriptive analysis was performed.

RESULTS

We identified 14 unique programs across the 2 scans. Eleven programs located in urban centres in British Columbia and Ontario participated in the first scan. At the time of the second scan, 2 of these programs were on hold and 2 of 3 newly established programs were in Alberta. The total capacity of all participating programs was 420 clients at most. Four service delivery models were identified; iOAT was most commonly integrated within existing health and social services. All programs offered hydromorphone, and 1 program also offered diacetylmorphine. In the first scan, 73% of clients (133/183) were male; the mean age of clients was 47 years. Limited capacity, pharmacy operations and lack of diacetylmorphine access were among the most frequently reported barriers. The most commonly reported facilitators included client-centred care, client relationships and access to other health and social support.

INTERPRETATION

Evidence indicates that iOAT can be successfully implemented using diverse service delivery models. Future work should facilitate scale-up of this evidence-based treatment where gaps persist in high-risk communities.

Seeking shelter: homelessness and COVID-19

Those experiencing homelessness in Canada are impacted inequitably by COVID-19 due to their increased exposure, vulnerability of environment and medical comorbidities, and their lack of access to preventive care and treatment in the context of the pandemic. In shelter environments one is unable to effectively physically distance, maintain hygiene, obtain a test, or isolate. As a result, unique strategies are required for this population to protect them and those who serve them. Recommendations are provided to reduce or prevent further negative consequences from the COVID-19 pandemic for people experiencing homelessness. These recommendations were informed by a systematic review of the literature, as well as a jurisdictional scan. Where evidence did not exist, expert consensus from key providers and those experiencing homelessness throughout Canada was included. These recommendations recognize the need for short-term interventions to mitigate the immediate risk to this community, including coordination of response, appropriate precautions and protective equipment, reducing congestion, cohorting, testing, case and contact management strategies, dealing with outbreaks, isolation centres, and immunization. Longer-term recommendations are also provided with a view to ending homelessness by addressing the root causes of homelessness and by the provision of adequate subsidized and supportive housing through a Housing First strategy. It is imperative that meaningful changes take place now in how we serve those experiencing homelessness and how we mitigate specific vulnerabilities. These recommendations call for intersectoral, collaborative engagement to work for solutions targeted towards protecting the most vulnerable within our community through both immediate actions and long-term planning to eliminate homelessness.

Barriers and facilitators to a novel low-barrier hydromorphone distribution program in Vancouver, Canada: a qualitative study

BACKGROUND

North America is experiencing an overdose crisis driven by illicitly-manufactured fentanyl, related analogues, and fentanyl-adulterated drugs. The concept of 'safe supply' has been suggested as a potential measure to address the overdose crisis by providing a regulated alternative to illicit opioids to people at high risk of fatal overdose. In January 2019, a novel hydromorphone tablet distribution program was implemented within an overdose prevention site in Vancouver, Canada's Downtown Eastside neighbourhood. This study explored barriers and facilitators to engagement with this program.

METHODS

In-depth interviews were conducted with 42 participants enrolled in the hydromorphone tablet distribution program, and over 100 h of ethnographic observation were conducted in and around the study site. Thematic analysis of the interviews and ethnographic observation focused on program operation, including barriers and facilitators to program uptake, access, and engagement.

RESULTS

Barriers to program engagement identified include: limited operating hours and dose schedule, co-location within the overdose prevention site (e.g., wait times), and receiving the generic formulation of hydromorphone. Facilitators identified include: having access to a reliable source of opioids, co-location within the overdose prevention site (e.g., low-barrier design), experiences of agency, and program flexibility.

CONCLUSION

Our findings demonstrate key implementation and operational considerations of safe supply programs. In particular, lower-barrier design and operational features should be considered to improve uptake and engagement. Safe opioid supply programs are a promising intervention to address North America's ongoing overdose crisis by providing people at high risk of fatal overdose an alternative to the toxic drug supply.

Use of a novel prescribing approach for the treatment of opioid use disorder: Buprenorphine/naloxone micro-dosing - a case series

INTRODUCTION AND AIMS

Buprenorphine/naloxone is an evidence-based treatment for opioid use disorder, but an identified limitation is the period of required opioid abstinence prior to induction on the medication. 'Micro-dosing', or using incrementally increasing doses of buprenorphine/naloxone over time, may be a way to overcome this challenge as it can be done in parallel with the ongoing use of other opioids (either illicit or prescribed).

DESIGN AND METHODS

A retrospective case series (January to December 2018) was completed of seven participants who underwent buprenorphine/naloxone induction using micro-dosing at two outpatient addiction clinics in Vancouver, Canada.

RESULTS

Seven participants completed a 7-day buprenorphine/naloxone micro-dosing protocol. Prior to and during the induction, one participant was prescribed methadone, three were prescribed slow release oral morphine and three used only illicit fentanyl. Participants were prescribed sublingual buprenorphine/naloxone: 0.5 mg once daily (day 1), 0.5 mg twice daily (BID; day 2), 1 mg BID (day 3), 2 mg BID (day 4), 3 mg BID (day 5), 4 mg BID (day 6) and 12 mg once daily (day 7). On day 7, all prescribed or illicit full opioid agonists were discontinued. Buprenorphine/naloxone was subsequently titrated to a daily dose of between 12 and 32 mg. All patients reported success with buprenorphine/naloxone induction with no precipitated withdrawal.

DISCUSSION AND CONCLUSIONS

Buprenorphine/naloxone micro-dosing may offer a promising alternative approach for successful induction for individuals with opioid use disorder who desire treatment with buprenorphine/naloxone, and further research to determine effectiveness is warranted.

A Low-Barrier and Comprehensive Community-Based Harm-Reduction Site in Vancouver, Canada

"The Molson" is a low-barrier, peer-staffed, supervised consumption site located in Vancouver, Canada. In addition to overdose response, this site offers drug checking and a colocated injectable hydromorphone treatment program, and it distributes tablet and liquid hydromorphone to service users at high risk of overdose. Our evaluation suggests benefits of this program in creating service continuums and preventing overdose deaths. From September 2017 to August 2019, the site had 128 944 visits, reversed 770 overdoses, and had no overdose deaths.

Transitioning a patient from injectable opioid agonist therapy to sublingual buprenorphine/naloxone for the treatment of opioid use disorder using a microdosing approach

In the wake of North America's opioid crisis, access to evidence-based treatment for opioid use disorder (OUD) is of critical importance. While buprenorphine/naloxone and methadone are currently indicated as first-line medications for the treatment of OUD, there are a proportion of individuals who do not benefit from these therapies. Recent Canadian guidelines suggest the use of alternate therapies, including slow-release oral morphine or injectable opioid agonist therapy (iOAT) for individuals unsuccessful with either methadone or buprenorphine/naloxone. While the guidelines highlight the need to intensify OUD treatment as disease severity increases, equally important is the consideration for deintensification of treatment (eg, from iOAT to an oral opioid agonist treatment (OAT) option) following successful stabilisation. Literature addressing how best to accomplish this, however, is currently lacking. Accordingly, the case presented here describes a patient that successfully transitions from iOAT to oral buprenorphine/naloxone using a novel induction approach termed microdosing.

Supervised injectable opioid agonist therapy in a supported housing setting for the treatment of severe opioid use disorder

Currently, North America is facing a national opioid overdose crisis. Opioid use disorder (OUD) is a chronic, relapsing condition requiring varying intensities of treatment. Injectable opioid agonist therapy (iOAT) is an effective, high-intensity treatment option for people who are unsuccessful on conventional oral opioid agonist treatments (eg, methadone, buprenorphine). This case highlights the effectiveness of the provision of iOAT in a low-barrier setting. More specifically, we discuss a patient with severe OUD and untreated HIV infection, who was disengaged from medical care and, consequently, was prescribed iOAT in a supportive housing setting.

Sustained release oral morphine as an alternative to methadone for the treatment of opioid-use disorder post Torsades de Pointes cardiac arrest

In most settings, approved medications for the treatment of opioid-use disorder include methadone and buprenorphine/naloxone, and in some settings, naltrexone. We present a case in which methadone administration was associated with an in-hospital episode of Torsades de Pointes in a patient who was subsequently maintained on sustained release oral morphine (SROM) for treatment of his opioid-use disorder. This transition was made in the context of long-term compliance to methadone maintenance, and with a previous adverse reaction to buprenorphine/naloxone precluding its use. The change to SROM, supported by emerging evidence, resulted in a reduction in the patient's measured QTc interval, prevention of further arrhythmias and continued abstinence from illicit opioid-use. In this context, we believe careful consideration should be given to the use of SROM.

Impact of unstable housing on all-cause mortality among persons who inject drugs

Background

Illicit drug injecting is a well-established risk factor for morbidity and mortality. However, a limited number of prospective studies have examined the independent effect of unstable housing on mortality among persons who inject drugs (PWIDs). In this study we sought to identify if a relationship exists between unstable housing and all-cause mortality among PWIDs living in Vancouver, Canada.

Methods

PWIDs participating in two prospective cohort studies in Vancouver, Canada were followed between May 1996 and December 2012. Cohort data were linked to the provincial vital statistics database to ascertain mortality rates and causes of death. We used multivariate Cox proportional hazards regression to determine factors associated with all-cause mortality and to investigate the independent relationship between unstable housing and time to all-cause mortality.

Results

During the study period, 2453 individuals were followed for a median of 69 months (Inter-quartile range [IQR]: 34 – 113). In total, there were 515 (21.0%) deaths for an incidence density of 3.1 (95% Confidence Interval [CI]: 2.8 – 3.4) deaths per 100 person years. In multivariate analyses, after adjusting for potential confounders including HIV infection and drug use patterns, unstable housing remained independently associated with all-cause mortality (adjusted hazard ratio [AHR] = 1.30, 95% CI: 1.08 – 1.56).

Conclusions

These findings demonstrate that unstable housing is an important risk factor for mortality independent of known risk factors including HIV infection and patterns of drug use. This study highlights the urgent need to provide supportive housing interventions to address elevated levels of preventable mortality among this population.

Accounting for false positive detection error induced by transient individuals

Context In metapopulations, colonisation is the result of dispersal from neighbouring occupied patches, typically juveniles dispersing from natal to breeding sites. When occupancy dynamics are dispersal driven, occupancy should refer to the presence of established, breeding populations. The detection of transient individuals at sites that are, by definition, unoccupied (i.e. false positive detections), may result in misleading conclusions about metapopulation dynamics. Until recently, the issue of false positives has been considered negligible and current efforts to account for such error have been restricted to the context of species misidentification. However, the detection of transient individuals visiting multiple sites while dispersing is a distinct source of false positives that can bias estimates of occupancy because visited sites do not contribute to metapopulation dynamics in the same way as do sites occupied by established, reproducing populations. Although transient-induced false positive error presents a challenge to occupancy studies aiming to account for all sources of detection error and estimate occupancy without bias, accounting for it has received little attention. Aims Using a novel application of an existing occupancy model, we sought to account for false positives that result from transient individuals being observed at truly unoccupied sites (i.e. where no establishment has occurred). Methods We applied a Bayesian multi-season occupancy model correcting for false negative and false positive errors, to 3 years of detection or non-detection data from a metapopulation of water voles, Arvicola amphibious, in which both types of patch-state misclassification are suspected. Key results We provide evidence that transient individuals can cause false positive detection errors. We then demonstrate the flexibility of the occupancy model to account for both false negative and false positive detection errors beyond the typical application to species misidentification. Accounting for both types of observation error reduces the bias in estimates of occupancy and avoids misleading conclusions about the status of (meta) populations by allowing for the distinction to be made between resident and transient occupancy. Conclusion In many species, transience may result in patch-state misclassification which needs to be accounted for so as to draw correct inference about metapopulation status. Making the distinction between occupancy by established populations and visitation by transients will influence how we interpret patch occupancy dynamics, with important implications for the management of wildlife. Implications The ability to estimate occupancy free of bias induced by false positive detections can help ensure that downward trends in occupancy are detected despite such declines being accompanied by increasing frequency of transients associated with, for example, reductions in mate availability or failure to establish. Our approach can be applied to any occupancy study in which false positive detections are suspected because of the behaviour of the focal species.

A high-fat-diet-induced cognitive deficit in rats that is not prevented by improving insulin sensitivity with metformin

AIMS/HYPOTHESIS

We previously demonstrated that animals fed a high-fat (HF) diet for 10 weeks developed insulin resistance and behavioural inflexibility. We hypothesised that intervention with metformin would diminish the HF-feeding-evoked cognitive deficit by improving insulin sensitivity.

METHODS

Rats were trained in an operant-based matching and non-matching to position task (MTP/NMTP). Animals received an HF (45% of kJ as lard; n = 24), standard chow (SC; n = 16), HF + metformin (144 mg/kg in diet; n = 20) or SC + metformin (144 mg/kg in diet; n = 16) diet for 10 weeks before retesting. Body weight and plasma glucose, insulin and leptin were measured. Protein lysates from various brain areas were analysed for alterations in intracellular signalling or production of synaptic proteins.

RESULTS

HF-fed animals developed insulin resistance and an impairment in switching task contingency from matching to non-matching paradigm. Metformin attenuated the insulin resistance and weight gain associated with HF feeding, but had no effect on performance in either MTP or NMTP tasks. No major alteration in proteins associated with insulin signalling or synaptic function was detected in response to HF diet in the hypothalamus, hippocampus, striatum or cortex.

CONCLUSIONS/INTERPRETATION

Metformin prevented the metabolic but not cognitive alterations associated with HF feeding. The HF diet protocol did not change basal insulin signalling in the brain, suggesting that the brain did not develop insulin resistance. These findings indicate that HF diet has deleterious effects on neuronal function over and above those related to insulin resistance and suggest that weight loss may not be sufficient to reverse some damaging effects of poor diet.

Nrf2 is controlled by two distinct β-TrCP recognition motifs in its Neh6 domain, one of which can be modulated by GSK-3 activity

Identification of regulatable mechanisms by which transcription factor NF-E2 p45-related factor 2 (Nrf2) is repressed will allow strategies to be designed that counter drug resistance associated with its up-regulation in tumours that harbour somatic mutations in Kelch-like ECH-associated protein-1 (Keap1), a gene that encodes a joint adaptor and substrate receptor for the Cul3-Rbx1/Roc1 ubiquitin ligase. We now show that mouse Nrf2 contains two binding sites for β-transducin repeat-containing protein (β-TrCP), which acts as a substrate receptor for the Skp1-Cul1-Rbx1/Roc1 ubiquitin ligase complex. Deletion of either binding site in Nrf2 decreased β-TrCP-mediated ubiquitylation of the transcription factor. The ability of one of the two β-TrCP-binding sites to serve as a degron could be both increased and decreased by manipulation of glycogen synthase kinase-3 (GSK-3) activity. Biotinylated-peptide pull-down assays identified DSGIS³³⁸ and DSAPGS³⁷⁸ as the two β-TrCP-binding motifs in Nrf2. Significantly, our pull-down assays indicated that β-TrCP binds a phosphorylated version of DSGIS more tightly than its non-phosphorylated counterpart, whereas this was not the case for DSAPGS. These data suggest that DSGIS, but not DSAPGS, contains a functional GSK-3 phosphorylation site. Activation of GSK-3 in Keap1-null mouse embryonic fibroblasts (MEFs), or in human lung A549 cells that contain mutant Keap1, by inhibition of the phosphoinositide 3-kinase (PI3K) – protein kinase B (PKB)/Akt pathway markedly reduced endogenous Nrf2 protein and decreased to 10-50% of normal the levels of mRNA for prototypic Nrf2-regulated enzymes, including the glutamate-cysteine ligase catalytic and modifier subunits, glutathione S-transferases Alpha-1 and Mu-1, heme oxygenase-1 and NAD(P)H:quinone oxidoreductase-1. Pre-treatment of Keap1^−/− MEFs or A549 cells with the LY294002 PI3K inhibitor or the MK-2206 PKB/Akt inhibitor increased their sensitivity to acrolein, chlorambucil and cisplatin between 1.9-fold and 3.1-fold, and this was substantially attenuated by simultaneous pre-treatment with the GSK-3 inhibitor CT99021.

Disordered insulin secretion in the development of insulin resistance and Type 2 diabetes

For many years, the development of insulin resistance has been seen as the core defect responsible for the development of Type 2 diabetes. However, despite extensive research, the initial factors responsible for insulin resistance development have not been elucidated. If insulin resistance can be overcome by enhanced insulin secretion, then hyperglycaemia will never develop. Therefore, a β-cell defect is clearly required for the development of diabetes. There is a wealth of evidence to suggest that disorders in insulin secretion can lead to the development of decreased insulin sensitivity. In this review, we describe the potential initiating defects in Type 2 diabetes, normal pulsatile insulin secretion and the effects that disordered secretion may have on both β-cell function and hepatic insulin sensitivity. We go on to examine evidence from physiological and epidemiological studies describing β-cell dysfunction in the development of insulin resistance. Finally, we describe how disordered insulin secretion may cause intracellular insulin resistance and the implications this concept has for diabetes therapy. In summary, disordered insulin secretion may contribute to development of insulin resistance and hence represent an initiating factor in the progression to Type 2 diabetes.

Neuronal membranes are key to the pathogenesis of Alzheimer's disease: the role of both raft and non-raft membrane domains

Membrane rafts are sterol- and sphingolipid-enriched domains that compartmentalize cellular processes. Membrane rafts isolated from post-mortem AD brain are enriched in both β-amyloid and phosphorylated tau. Proteolytic processing of APP to generate β-amyloid, the principle component of amyloid plaques, can occur in membrane rafts, implicating them in the pathogenesis of Alzheimer's disease (AD). Secondary to their role in β-amyloid generation, membrane rafts have more recently been implicated in the accumulation, aggregation and degradation of β-amyloid, with evidence supporting a specific role for membrane raft gangliosides in the binding and aggregation of β-amyloid. In addition, membrane domain composition has a direct impact on both the generation of β-amyloid and its subsequent toxic actions and as such is a key target for the development of therapeutic strategies. This mini-review will focus on recent advances in our understanding of the relevance of membrane composition, of both raft and non-raft domains, to AD progression in models and in human disease. We will discuss how manipulation of membrane composition can alter both the proteolytic processing of APP and the subsequent binding and aggregation of β-amyloid peptide.

Increased CRMP2 phosphorylation is observed in Alzheimer's disease; does this tell us anything about disease development?

Collapsin response mediator protein-2 (CRMP2) was recently identified as a physiological substrate for GSK3 and Cdk5, two protein kinases suggested to exhibit greater activity in Alzheimer's disease (AD). Indeed, phosphorylation of CRMP2, at the residues targeted by GSK3 and Cdk5, is relatively high in cortex isolated from human AD brain, as well as in the brains of animal models of AD, while phospho-CRMP2 is found in neurofibrillary tangles. In mouse models of AD, increased phosphorylation occurs prior to pathology. Although CRMP2 has no known enzymatic activity, a great deal of information is appearing on its importance in neuronal development and polarity, as well as in axon growth and guidance. In this mini-review, we examine what is known about CRMP2 function, how that is controlled by phosphorylation, what alterations in molecular mechanisms could lead to the abnormally high CRMP2 phosphorylation in AD, and whether this is likely to be specific to AD or occur in other forms of neurodegeneration. This will include discussion of the evidence for increased GSK3 or Cdk5 activity, for decreased phosphatase activity, or the upregulation of other CRMP2 protein kinases in AD. Importantly, we will compare the processes that may contribute to increased CRMP2 phosphorylation with those known to increase tau hyperphosphorylation in AD, and whether these are likely to be part of disease development or a useful early marker for AD.

Elevated blood-lead levels in first nation people of Northern Ontario Canada: policy implications

We evaluated the preliminary impact of the Canadian "non-toxic" shotshell policy, for the hunting of migratory game birds, by examining blood-lead levels of First Nations people living in sub-arctic Canada. If the use of lead shotshell was the major source of lead exposure as has been postulated and the ban on the use of lead shotshell for hunting migratory birds was immediately effective, we would expect that blood-lead levels would be typical of a geographic area remote from industrialization. Our findings present some concern in that approximately 18% of the 196 First Nations people examined had blood-lead levels > or =100 microg/L.

Functional characterisation of the regulation of CAAT enhancer binding protein alpha by GSK-3 phosphorylation of Threonines 222/226

BACKGROUND

Glycogen Synthase Kinase-3 (GSK3) activity is repressed following insulin treatment of cells. Pharmacological inhibition of GSK3 mimics the effect of insulin on Phosphoenolpyruvate Carboxykinase (PEPCK), Glucose-6 Phosphatase (G6Pase) and IGF binding protein-1 (IGFBP1) gene expression. CAAT/enhancer binding protein alpha (C/EBPalpha) regulates these gene promoters in liver and is phosphorylated on two residues (T222/T226) by GSK3, although the functional outcome of the phosphorylation has not been established. We aimed to establish whether CEBPalpha is a link between GSK3 and these gene promoters.

RESULTS

C/EBPalpha represses the IGFBP1 thymine-rich insulin response element (TIRE), but mutation of T222 or T226 of C/EBPalpha to non-phosphorylatable alanines has no effect on C/EBPalpha activity in liver cells (towards the TIRE or a consensus C/EBP binding sequence). Phosphorylation of T222/T226 is decreased by GSK3 inhibition, suggesting GSK3 does phosphorylate T222/226 in intact cells. However, phosphorylation was not altered by treatment of liver cells with insulin. Meanwhile C/EBPalpha activity in 3T3 L1 preadipocytes was enhanced by mutation of T222/T226 and/or S230 to alanine residues. Finally, we demonstrate that C/EBPalpha is a very poor substrate for GSK3 in vitro and in cells.

CONCLUSION

The work demonstrates an important role for this domain in the regulation of C/EBPalpha activity in adipocytes but not hepatocytes, however GSK3 phosphorylation of these residues does not mediate regulation of this C/EBP activity. In short, we find no evidence that C/EBPalpha activity is regulated by direct phosphorylation by GSK3.

Intrapulmonary Concentrations of Telithromycin: Clinical Implications for Respiratory Tract Infections due to Streptococcus pneumoniae

BACKGROUND

Antimicrobial efficacy is dependent on the ability of the agent to reach the site of infection. To assess the bronchopulmonary drug disposition of a novel ketolide, telithromycin (TEL), the epithelial lining fluid (ELF) and alveolar macrophage (AM) concentrations were utilized as a surrogate marker for lung penetration.

METHODS

Adult subjects scheduled for diagnostic bronchoscopy received oral TEL 800 mg once daily for 5 days. Plasma and bronchoalveolar lavage (BAL) samples were collected 2, 8, 12, or 24 h after the last TEL dose. TEL concentrations in the ELF and AM were determined using a validated HPLC assay. ELF drug concentrations were calculated using the urea dilution method.

RESULTS

Seventeen subjects with a mean age 65 +/- 13 years and a mean weight of 81 +/- 25 kg completed this open-label study. The median (range) TEL concentrations in plasma and ELF, respectively, were 1.09 mg/l (1.00-4.81) and 3.91 mg/l (2.64-9.59) at 2 h (n = 6), 0.48 and 1.09 mg/l at 8 h (n = 1), 0.65 mg/l (0.18-1.55) and 1.81 mg/l (0.61-10.0) at 12 h (n = 5), and 0.11 mg/l (0.09-0.24) and 0.69 mg/l (0.15-1.58) at 24 h (n = 5). The median AM concentrations obtained from these subjects were 53.35 mg/l at 2 h, 32.55 mg/l at 8 h, 65.96 mg/l at 12 h, and 26.43 mg/l at 24 h. Overall TEL was well tolerated. No discontinuation was required due to an adverse event.

CONCLUSIONS

TEL displayed high intrapulmonary penetration with ELF concentrations exceeding that of plasma at all time points. AM intracellular concentrations were multiple times higher than in the ELF and plasma. These data support the clinical efficacy of TEL against intracellular and extracellular pathogens, particularly with Streptococcus pneumoniae having an MIC(90 )well below achievable concentrations at the site of infection.

The experience of empowerment in in-home services delivery

In-home health services strive for client-centredness, involvement, and ultimately, empowerment, but economic constraint may undermine these aims. The purpose of this study was to explore the everyday experience of in-home care, with particular attention to the enactment of empowerment in the care partnership. In-depth interviews with a maximally varied sample of clients, informal caregivers, and providers uncovered relationships largely reflecting the traditional expert model of care. Findings afford insights into the unrecognized and undervalued personal knowledge of clients, caregivers, and in-home service providers, the professional and structural hegemony and consequent disempowered group behaviour of those who share the experience of care, and the hesitance of clients to engage as equitable partners in care. Strategies to achieve empowerment approaches to in-home health services are identified.

Restricted genetic and antigenic diversity of Plasmodium falciparum under mesoendemic transmission in the Venezuelan Amazon

The study of genetic diversity in malaria populations is expected to provide new insights for the deployment of control measures. Plasmodium falciparum diversity in Africa and Asia is thought to reflect endemicity. In comprehensive epidemiological surveys reported here the genetic and antigenic structure of P. falciparum in the Venezuelan Amazon were studied over a 2-year period. DNA polymorphisms in glutamate-rich protein (GLURP), merozoite-surface protein 1 (MSP1) and MSP2 genes, in a multicopy element (PfRRM), all showed low diversity, 1 predominant genotype, and virtually no multi-clonal infections. Moreover, linkage disequilibrium was seen between GLURP, MSP1 and MSP2. Specific antibody responses against MSP1 and MSP2 recombinant antigens reflected the low genetic diversity observed in the parasite population. This is unexpected in a mesoendemic area, and suggests that the low diversity here may not only relate to endemicity but to other influences such as a bottleneck effect. Linkage disequilibrium and a predominant genotype may imply that P. falciparum frequently propagates with an epidemic or clonal population structure in the Venezuelan Amazon.

Work in progress. Integrating physicians' services in the home

OBJECTIVE

While increasing acuity levels and the concomitant complexity of service demand that physicians be involved in in-home care, conflicting evidence and opinions do not show how this can best be achieved.

DESIGN

A phenomenologic research design was used to obtain insights into the challenges and opportunities of integrating physicians' services into the usual in-home services in London, Ont.

SETTING

Home care in London, Ont.

PARTICIPANTS

Twelve participants included three patients, two family caregivers, two family physicians, the program's nurse practitioner, two case managers, and two community nurses.

METHOD

In-depth interviews with a maximally varied purposeful sample of patients, caregivers, and providers were analyzed using immersion and crystallization techniques.

MAIN FINDINGS

Findings revealed the potential for enhanced continuity of care and interdisciplinary team functioning. Having a nurse practitioner, interdisciplinary team-building exercises and meetings, regular face-to-face contact among all providers, support for family caregivers, and 24-hour coverage for physicians were found to be essential for success.

CONCLUSION

Integration of services takes time, money, and sustained commitment, particularly when undertaken in geographically isolated communities. Informed choice and a fair remuneration system remain important considerations for family physicians.

A randomized controlled trial using glycemic plus fetal ultrasound parameters versus glycemic parameters to determine insulin therapy in gestational diabetes with fasting hyperglycemia

OBJECTIVE

To compare management based on maternal glycemic criteria with management based on relaxed glycemic criteria and fetal abdominal circumference (AC) measurements in order to select patients for insulin treatment of gestational diabetes mellitus (GDM) with fasting hyperglycemia.

RESEARCH DESIGN AND METHODS

In a pilot study, 98 women with fasting plasma glucose (FPG) concentrations of 105-120 mg/dl were randomized. The standard group received insulin treatment. The experimental group received insulin if the AC, measured monthly, was > or =70th percentile and/or if any venous FPG measurement was >120 mg/dl. Power was projected to detect a 250-g difference in birth weights.

RESULTS

Gestational ages, maternal glycemia, and AC percentiles were similar at randomization. After initiation of protocol, venous FPG (P = 0.003) and capillary blood glucose levels (P = 0.049) were significantly lower in the standard group. Birth weights (3,271 +/- 458 vs. 3,369 +/- 461 g), frequencies of birth weights >90th percentile (6.3 vs 8.3%), and neonatal morbidity (25 vs. 25%) did not differ significantly between the standard and experimental groups, respectively. The cesarean delivery rate was significantly lower (14.6 vs. 33.3%, P = 0.03) in the standard group; this difference was not explained by birth weights. In the experimental group, infants of women who did not receive insulin had lower birth weights than infants of mothers treated with insulin (3,180 +/- 425 vs. 3,482 +/- 451 g, P = 0.03).

CONCLUSIONS

In women with GDM and fasting hyperglycemia, glucose plus fetal AC measurements identified pregnancies at low risk for macrosomia and resulted in the avoidance of insulin therapy in 38% of patients without increasing rates of neonatal morbidity.

Antagonistic effects of phorbol esters on insulin regulation of insulin-like growth factor-binding protein-1 (IGFBP-1) but not glucose-6-phosphatase gene expression

Glucose-6-phosphatase (G6Pase) and insulin-like growth factor-binding protein-1 (IGFBP-1) genes contain a homologous promoter sequence that is required for gene repression by insulin. Interestingly, this element interacts with members of the forkhead family of transcription factors [e.g. HNF3 (hepatic nuclear factor 3), FKHR (forkhead in rhabdomyosarcoma)] in vitro, while insulin promotes the phosphorylation and inactivation of FKHR in a phosphatidylinositol 3-kinase- and protein kinase B (PKB)-dependent manner. This mechanism has been proposed to underlie insulin action on G6Pase and IGFBP-1 gene transcription. However, we find that treatment of cells with phorbol esters mimics the effect of insulin on G6Pase, but not IGFBP-1, gene expression. Indeed, phorbol ester treatment actually blocks the ability of insulin to repress IGFBP-1 gene expression. In addition, the action of phorbol esters is significantly reduced by inhibition of the p42/p44 mitogen-activated protein (MAP) kinase pathway. However insulin-induced phosphorylation of PKB or FKHR is not affected by the presence of phorbol esters. Therefore we suggest that activation of p42/p44 MAP kinases will reduce the sensitivity of the IGFBP-1 gene promoter, but not the G6Pase gene promoter, to insulin. Importantly, the activation of PKB and phosphorylation of FKHR is not, in itself, sufficient to reduce IGFBP-1 gene expression in the presence of phorbol esters.

Ca2+-independent smooth muscle contraction. a novel function for integrin-linked kinase

Smooth muscle contraction follows an increase in cytosolic Ca(2+) concentration, activation of myosin light chain kinase, and phosphorylation of the 20-kDa light chain of myosin at Ser(19). Several agonists acting via G protein-coupled receptors elicit a contraction without a change in [Ca(2+)](i) via inhibition of myosin light chain phosphatase and increased myosin phosphorylation. We showed that microcystin (phosphatase inhibitor)-induced contraction of skinned smooth muscle occurred in the absence of Ca(2+) and correlated with phosphorylation of myosin light chain at Ser(19) and Thr(18) by a kinase distinct from myosin light chain kinase. In this study, we identify this kinase as integrin-linked kinase. Chicken gizzard integrin-linked kinase cDNA was cloned, sequenced, expressed in E. coli, and shown to phosphorylate myosin light chain in the absence of Ca(2+) at Ser(19) and Thr(18). Subcellular fractionation revealed two distinct populations of integrin-linked kinase, including a Triton X-100-insoluble component that phosphorylates myosin in a Ca(2+)-independent manner. These results suggest a novel function for integrin-linked kinase in the regulation of smooth muscle contraction via Ca(2+)-independent phosphorylation of myosin, raise the possibility that integrin-linked kinase may also play a role in regulation of nonmuscle motility, and confirm that integrin-linked kinase is indeed a functional protein-serine/threonine kinase.