Safety and Efficacy of Apitegromab in Patients With Spinal Muscular Atrophy Types 2 and 3: The Phase 2 TOPAZ Study

BACKGROUND AND OBJECTIVES

Currently approved therapies for spinal muscular atrophy (SMA) reverse the degenerative course, leading to better functional outcome, but they do not address the impairment arising from preexisting neurodegeneration. Apitegromab, an investigational, fully human monoclonal antibody, inhibits activation of myostatin (a negative regulator of skeletal muscle growth), thereby preserving muscle mass. The phase 2 TOPAZ trial assessed the safety and efficacy of apitegromab in individuals with later-onset type 2 and type 3 SMA.

METHODS

In this study, designed to investigate potential meaningful combinations of eligibility and treatment regimen for future studies, participants aged 2-21 years received IV apitegromab infusions every 4 weeks for 12 months in 1 of 3 cohorts. Cohort 1 stratified ambulatory participants aged 5-21 years into 2 arms (apitegromab 20 mg/kg alone or in combination with nusinersen); cohort 2 evaluated apitegromab 20 mg/kg combined with nusinersen in nonambulatory participants aged 5-21 years; and cohort 3 blindly evaluated 2 randomized apitegromab doses (2 and 20 mg/kg) combined with nusinersen in younger participants ≥2 years of age. The primary efficacy measure was mean change from baseline using the Hammersmith Functional Motor Scale version appropriate for each cohort. Data were analyzed using a paired t test with 2-sided 5% type 1 error for the mean change from baseline for predefined cohort-specific primary efficacy end points.

RESULTS

Fifty-eight participants (mean age 9.4 years) were enrolled at 16 trial sites in the United States and Europe. Participants had been treated with nusinersen for a mean of 25.9 months before enrollment in any of the 3 trial cohorts. At month 12, the mean change from baseline in Hammersmith scale score was -0.3 points (95% CI -2.1 to 1.4) in cohort 1 (n = 23), 0.6 points (-1.4 to 2.7) in cohort 2 (n = 15), and in cohort 3 (n = 20), the mean scores were 5.3 (-1.5 to 12.2) and 7.1 (1.8 to 12.5) for the 2-mg/kg (n = 8) and 20-mg/kg (n = 9) arms, respectively. The 5 most frequently reported treatment-emergent adverse events were headache (24.1%), pyrexia (22.4%), upper respiratory tract infection (22.4%), cough (22.4%), and nasopharyngitis (20.7%). No deaths or serious adverse reactions were reported.

DISCUSSION

Apitegromab led to improved motor function in participants with later-onset types 2 and 3 SMA. These results support a randomized, placebo-controlled phase 3 trial of apitegromab in participants with SMA.

TRIAL REGISTRATION INFORMATION

This trial is registered with ClinicalTrials.gov (NCT03921528).

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that apitegromab improves motor function in later-onset types 2 and 3 spinal muscular atrophy.

Adjudicating Mild Cognitive Impairment Due to Alzheimer's Disease as a Novel Endpoint Event in the TOMMORROW Prevention Clinical Trial

BACKGROUND

The onset of mild cognitive impairment (MCI) is an essential outcome in Alzheimer's disease (AD) prevention trials and a compelling milestone for clinically meaningful change. Determining MCI, however, may be variable and subject to disagreement. Adjudication procedures may improve the reliability of these determinations. We report the performance of an adjudication committee for an AD prevention trial.

METHODS

The TOMMORROW prevention trial selected cognitively normal participants at increased genetic risk for AD and randomized them to low-dose pioglitazone or placebo treatment. When adjudication criteria were triggered, a participant's clinical information was randomly assigned to a three-member panel of a six-member independent adjudication committee. Determination of whether or not a participant reached MCI due to AD or AD dementia proceeded through up to three review stages - independent review, collaborative review, and full committee review - requiring a unanimous decision and ratification by the chair.

RESULTS

Of 3494 participants randomized, the committee adjudicated on 648 cases from 386 participants, resulting in 96 primary endpoint events. Most participants had cases that were adjudicated once (n = 235, 60.9%); the rest had cases that were adjudicated multiple times. Cases were evenly distributed among the eight possible three-member panels. Most adjudicated cases (485/648, 74.8%) were decided within the independent review (stage 1); 14.0% required broader collaborative review (stage 2), and 11.1% needed full committee discussion (stage 3). The primary endpoint event decision rate was 39/485 (8.0%) for stage 1, 29/91 (31.9%) for stage 2, and 28/72 (38.9%) for stage 3. Agreement between the primary event outcomes supported by investigators' clinical diagnoses and the decisions of the adjudication committee increased from 50% to approximately 93% (after around 100 cases) before settling at 80-90% for the remainder of the study.

CONCLUSIONS

The adjudication process was designed to provide independent, consistent determinations of the trial endpoints. These outcomes demonstrated the extent of uncertainty among trial investigators and agreement between adjudicators when the transition to MCI due to AD was prospectively assessed. These methods may inform clinical endpoint determination in future AD secondary prevention studies. Reliable, accurate assessment of clinical events is critical for prevention trials and may mean the difference between success and failure.

Safety and efficacy of pioglitazone for the delay of cognitive impairment in people at risk of Alzheimer's disease (TOMMORROW): a prognostic biomarker study and a phase 3, randomised, double-blind, placebo-controlled trial

BACKGROUND

The identification of people at risk of cognitive impairment is essential for improving recruitment in secondary prevention trials of Alzheimer's disease. We aimed to test and qualify a biomarker risk assignment algorithm (BRAA) to identify participants at risk of developing mild cognitive impairment due to Alzheimer's disease within 5 years, and to evaluate the safety and efficacy of low-dose pioglitazone to delay onset of mild cognitive impairment in these at-risk participants.

METHODS

In this phase 3, multicentre, randomised, double-blind, placebo-controlled, parallel-group study, we enrolled cognitively healthy, community living participants aged 65-83 years from 57 academic affiliated and private research clinics in Australia, Germany, Switzerland, the UK, and the USA. By use of the BRAA, participants were grouped as high risk or low risk. Participants at high risk were randomly assigned 1:1 to receive oral pioglitazone (0·8 mg/day sustained release) or placebo, and all low-risk participants received placebo. Study investigators, site staff, sponsor personnel, and study participants were masked to genotype, risk assignment, and treatment assignment. The planned study duration was the time to accumulate 202 events of mild cognitive impairment due to Alzheimer's disease in White participants who were at high risk (the population on whom the genetic analyses that informed the BRAA development was done). Primary endpoints were time-to-event comparisons between participants at high risk and low risk given placebo (for the BRAA objective), and between participants at high risk given pioglitazone or placebo (for the efficacy objective). The primary analysis included all participants who were randomly assigned, received at least one dose of study drug, and had at least one valid post-baseline visit, with significance set at p=0·01. The safety analysis included all participants who were randomly assigned and received at least one dose of study medication. An efficacy futility analysis was planned for when approximately 33% of the anticipated events occurred in the high-risk, White, non-Hispanic or Latino group. This trial is registered with ClinicalTrials.gov, NCT01931566.

FINDINGS

Between Aug 28, 2013, and Dec 21, 2015, we enrolled 3494 participants (3061 at high risk and 433 at low risk). Of those participants, 1545 were randomly assigned to pioglitazone and 1516 to placebo. 1104 participants discontinued treatment (464 assigned to the pioglitazone group, 501 in the placebo high risk group, and 139 in the placebo low risk group). 3399 participants had at least one dose of study drug or placebo and at least one post-baseline follow-up visit, and were included in the efficacy analysis. 3465 participants were included in the safety analysis (1531 assigned to the pioglitazone group, 1507 in the placebo high risk group, and 427 in the placebo low risk group). In the full analysis set, 46 (3·3%) of 1406 participants at high risk given placebo had mild cognitive impairment due to Alzheimer's disease, versus four (1·0%) of 402 participants at low risk given placebo (hazard ratio 3·26, 99% CI 0·85-12·45; p=0·023). 39 (2·7%) of 1430 participants at high risk given pioglitazone had mild cognitive impairment, versus 46 (3·3%) of 1406 participants at high risk given placebo (hazard ratio 0·80, 99% CI 0·45-1·40; p=0·307). In the safety analysis set, seven (0·5%) of 1531 participants at high risk given pioglitazone died versus 21 (1·4%) of 1507 participants at high risk given placebo. There were no other notable differences in adverse events between groups. The study was terminated in January, 2018, after failing to meet the non-futility threshold.

INTERPRETATION

Pioglitazone did not delay the onset of mild cognitive impairment. The biomarker algorithm demonstrated a 3 times enrichment of events in the high risk placebo group compared with the low risk placebo group, but did not reach the pre-specified significance threshold. Because we did not complete the study as planned, findings can only be considered exploratory. The conduct of this study could prove useful to future clinical development strategies for Alzheimer's disease prevention studies.

FUNDING

Takeda and Zinfandel.

From Silos to Solidarity: Case Study of a Patient-Centered, Integrative Approach to Opioid Tapering and Chronic Pain Mitigation in a Multidisciplinary AIDS Clinic

Background:

People with HIV (PWH) are at a disproportionate risk for experiencing both chronic pain and opioid use disorder (OUD). Prescription opioid tapering is typically addressed within the “silo model” of medical care, whereby attention is focused solely on opioid addiction rather than also addressing chronic pain management, and limited communication occurs between patient and providers.

Objective:

This descriptive case study examined an integrative, collaborative care model consisting of Provider, Physical Therapist (PT), and Patient aimed at decreasing chronic pain and opioid use within a multidisciplinary HIV/AIDS clinic.

Method:

A physical-therapy based model of chronic pain mitigation and physician-driven opioid tapering was implemented. The Provider, PT, and Patient worked collaboratively to address physiological pain, pain coping skills and opioid tapering. A patient case example was used to illustrate the implementation of the model for a future, larger study in the same patient population.

Results:

This model was feasible in this case example in terms of clinic workflow and acceptability to both the Patient and Providers in this clinic. After the intervention, the Patient’s pain was fully eliminated, and he had ceased all opioid use.

Conclusion:

Results of this case study suggest that utilizing an integrative, patient-centered approach to both chronic pain management and opioid tapering may be feasible within the context of a multidisciplinary HIV/AIDS clinic. Generalizability is limited by case study model; however, this gives insight into the value of a collaborative alternative compared to a “silo” model of opioid tapering and chronic pain management in preparation for a larger study.

The TOMMORROW study: Design of an Alzheimer's disease delay-of-onset clinical trial

Introduction

Alzheimer's disease (AD) is a continuum with neuropathologies manifesting years before clinical symptoms; thus, AD research is attempting to identify more disease-modifying approaches to test treatments administered before full disease expression. Designing such trials in cognitively normal elderly individuals poses unique challenges.

Methods

The TOMMORROW study was a phase 3 double-blind, parallel-group study designed to support qualification of a novel genetic biomarker risk assignment algorithm (BRAA) and to assess efficacy and safety of low-dose pioglitazone to delay onset of mild cognitive impairment due to AD. Eligible participants were stratified based on the BRAA (using TOMM40 rs 10524523 genotype, Apolipoprotein E genotype, and age), with high-risk individuals receiving low-dose pioglitazone or placebo and low-risk individuals receiving placebo. The primary endpoint was time to the event of mild cognitive impairment due to AD. The primary objectives were to compare the primary endpoint between high- and low-risk placebo groups (for BRAA qualification) and between high-risk pioglitazone and high-risk placebo groups (for pioglitazone efficacy). Approximately 300 individuals were also asked to participate in a volumetric magnetic resonance imaging substudy at selected sites.

Results

The focus of this paper is on the design of the study; study results will be presented in a separate paper.

Discussion

The design of the TOMMORROW study addressed many key challenges to conducting a dual-objective phase 3 pivotal AD clinical trial in presymptomatic individuals. Experiences from planning and executing the TOMMORROW study may benefit future AD prevention/delay-of-onset trials.

A pathway leading to a cation-binding pocket determines the selectivity of the NhaP2 antiporter in Vibrio cholerae 1

The Vc-NhaP2 antiporter from Vibrio cholerae exchanges H⁺ for K⁺ or Na⁺ but not for the smaller Li⁺. The molecular basis of this unusual selectivity remains unknown. Phyre² and Rosetta software were used to generate a structural model of the Vc-NhaP2. The obtained model suggested that a cluster of residues from different transmembrane segments (TMSs) forms a putative cation-binding pocket in the middle of the membrane: D133 and T132 from TMS V together with D162 and E157 of TMS VI. The model also suggested that L257, G258, and N259 from TMS IX together with T276, D273, Q280, and Y251 from TMS X as well as L289 and L342 from TMS XII form a transmembrane pathway for translocated ions with a built-in filter determining cation selectivity. Alanine-scanning mutagenesis of the identified residues verified the model by showing that structural modifications of the pathway resulted in altered cation selectivity and transport activity. In particular, L257A, G258A, Q280A, and Y251A variants gained Li⁺/H⁺ antiport capacity that was absent in the nonmutated antiporter. T276A, D273A, and L289A variants exclusively exchanged K⁺ for H⁺, while a L342A variant mediated Na⁺/H⁺ exchange only, thus maintaining strict alkali cation selectivity.

TOMMORROW neuropsychological battery: German language validation and normative study

Introduction

Assessment of preclinical Alzheimer's disease (AD) requires reliable and validated methods to detect subtle cognitive changes. The battery of standardized cognitive assessments that is used for diagnostic criteria for mild cognitive impairment due to AD in the TOMMORROW study have only been fully validated in English-speaking countries. We conducted a validation and normative study of the German language version of the TOMMORROW neuropsychological test battery, which tests episodic memory, language, visuospatial ability, executive function, and attention.

Methods

German-speaking cognitively healthy controls (NCs) and subjects with AD were recruited from a memory clinic at a Swiss medical center. Construct validity, test-retest, and alternate form reliability were assessed in NCs. Criterion and discriminant validities of the cognitive measures were tested using logistic regression and discriminant analysis. Cross-cultural equivalency of performance of the German language tests was compared with English language tests.

Results

A total of 198 NCs and 25 subjects with AD (aged 65-88 years) were analyzed. All German language tests discriminated NCs from persons with AD. Episodic memory tests had the highest potential to discriminate with almost twice the predictive power of any other domain. Test-retest reliability of the test battery was adequate, and alternate form reliability for episodic memory tests was supported. For most tests, age was a significant predictor of group effect sizes; therefore, normative data were stratified by age. Validity and reliability results were similar to those in the published US cognitive testing literature.

Discussion

This study establishes the reliability and validity of the German language TOMMORROW test battery, which performed similarly to the English language tests. Some variations in test performance underscore the importance of regional normative values. The German language battery and normative data will improve the precision of measuring cognition and diagnosing incident mild cognitive impairment due to AD in clinical settings in German-speaking countries.

Peginesatide to Manage Anemia in Chronic Kidney Disease Patients on Peritoneal Dialysis

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BACKGROUND

Peginesatide is a novel, synthetic, peptide-based pegylated erythropoiesis-stimulating agent that is designed specifically to stimulate the erythropoietin receptor. The purpose of the present study was to assess, for the first time, the efficacy and safety of peginesatide in chronic kidney disease (CKD) patients receiving peritoneal dialysis (PD) and previously on epoetin treatment. ♦

METHODS

In this open-label multicenter study, 59 PD patients with CKD were converted from epoetin (alfa or beta) to once-monthly peginesatide. Doses were titrated to maintain hemoglobin levels between 10 g/dL and 12 g/dL during the 25 weeks of the study. The primary endpoint was change from baseline in mean hemoglobin values during the evaluation period (weeks 20 - 25). ♦

RESULTS

The mean hemoglobin value during the evaluation period was 11.3 ± 1.07 g/dL, and the mean change from baseline was 0.10 ± 1.15 g/dL (95% confidence limits: -0.24, 0.44 g/dL). During the evaluation period, most patients maintained hemoglobin levels between 10 g/dL and 12 g/dL (63.0%) and within ±1.0 g/dL of baseline (60.9%). The median weekly epoetin dose at baseline was 96.0 U/kg, and the median starting peginesatide dose was 0.047 mg/kg. Forty-three patients (72.9%) completed the study. Six patients (10.2%) received red blood cell transfusions. The observed adverse event profile was consistent with underlying conditions in the PD patient population. The most common adverse event was peritonitis (20.3%), a complication commonly associated with PD. Four deaths occurred during the study (2 related to septic shock, and 1 each to myocardial ischemia and myasthenia gravis). ♦

CONCLUSIONS

In this study, once-monthly peginesatide maintained hemoglobin levels in PD patients after conversion from epoetin.

Peginesatide for maintenance treatment of anemia in hemodialysis and nondialysis patients previously treated with darbepoetin alfa

BACKGROUND AND OBJECTIVES

Peginesatide (Omontys) is a novel, synthetic, PEGylated, peptide-based erythropoiesis-stimulating agent (ESA) that is designed to specifically stimulate the erythropoietin receptor. This study evaluated maintenance of hemoglobin levels in patients after conversion from darbepoetin alfa to once-monthly peginesatide.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This open-label, multicenter study included 101 CKD patients, 52 of whom were receiving dialysis. The duration of the study was 24 weeks. The primary endpoint was the mean change in hemoglobin from baseline to the evaluation period (weeks 19-24). The study was conducted during the period from September 22, 2008 to December 24, 2009.

RESULTS

The mean change among hemodialysis patients was -0.42 g/dl (95% confidence interval, -0.65 to -0.19) and the mean change among CKD nondialysis patients was 0.49 g/dl (95% confidence interval, 0.26-0.71). The percentages of patients who maintained hemoglobin levels within ±1.0 g/dl of baseline values were as follows: 80.0% for hemodialysis and 68.1% for nondialysis, and73.3% for hemodialysis and 68.1% for nondialysis within the target range of 10.0-12.0 g/dl. Few patients received red blood cell transfusions (hemodialysis, 5.8%; nondialysis, 2.0%). Seventy-nine patients experienced adverse events, the majority of which were mild or moderate in severity. There were 40 serious adverse events and 2 deaths reported.

CONCLUSIONS

In this study, once-monthly peginesatide resulted in a slight decrease in mean hemoglobin levels in individuals on hemodialysis and a small increase in individuals with CKD who were not on dialysis.

Maintenance of heartburn relief after step-down from twice-daily proton pump inhibitor to once-daily dexlansoprazole modified release

BACKGROUND & AIMS

Many patients with gastroesophageal reflux disease (GERD) take a proton pump inhibitor (PPI) twice daily to control symptoms. Once-daily dexlansoprazole modified release (MR) has a dual-delayed release formulation, making it attractive for step-down management of patients whose symptoms are well controlled on twice-daily PPIs. We investigated whether step-down to once-daily dexlansoprazole controls heartburn in patients with GERD who were receiving twice-daily PPI therapy.

METHODS

Patients 18 years and older taking a twice-daily PPI for symptom control were enrolled (n = 178) in a single-blind, multicenter study; 163 patients completed the study and 142 patients met criteria for the efficacy analysis. During the 6-week screening and treatment periods, patients recorded the presence of heartburn symptoms twice daily in electronic diaries. Patients' heartburn was considered well controlled if they had an average of 1 symptom or fewer per week during the last 4 weeks of screening and treatment. After screening, qualified patients were switched to masked dexlansoprazole MR 30 mg and placebo for 6 weeks. The primary efficacy end point was the proportion of patients whose heartburn remained well controlled after step-down. GERD-related symptoms and quality of life (QOL) also were evaluated using the Patient Assessment of Upper Gastrointestinal Disorders Symptom Severity Index (PAGI-SYM) and the PAGI-QOL questionnaires, respectively.

RESULTS

After step-down to once-daily dexlansoprazole MR 30 mg, heartburn remained well controlled in 88% of patients (125 of 142). These patients were able to maintain their GERD-related symptom severity and QOL, indicated by marginal changes in the PAGI-SYM and PAGI-QOL total and subscale scores, respectively.

CONCLUSIONS

Most patients with GERD who take twice-daily PPI to control heartburn are able to successfully step down to once-daily dexlansoprazole 30 mg.

Down-regulation of the Notch pathway mediated by a gamma-secretase inhibitor induces anti-tumour effects in mouse models of T-cell leukaemia

BACKGROUND AND PURPOSE

gamma-Secretase inhibitors (GSIs) block NOTCH receptor cleavage and pathway activation and have been under clinical evaluation for the treatment of malignancies such as T-cell acute lymphoblastic leukaemia (T-ALL). The ability of GSIs to decrease T-ALL cell viability in vitro is a slow process requiring >8 days, however, such treatment durations are not well tolerated in vivo. Here we study GSI's effect on tumour and normal cellular processes to optimize dosing regimens for anti-tumour efficacy.

EXPERIMENTAL APPROACH

Inhibition of the Notch pathway in mouse intestinal epithelium was used to evaluate the effect of GSIs and guide the design of dosing regimens for xenograft models. Serum Abeta(40) and Notch target gene modulation in tumours were used to evaluate the degree and duration of target inhibition. Pharmacokinetic and pharmacodynamic correlations with biochemical, immunohistochemical and profiling data were used to demonstrate GSI mechanism of action in xenograft tumours.

KEY RESULTS

Three days of >70% Notch pathway inhibition was sufficient to provide an anti-tumour effect and was well tolerated. GSI-induced conversion of mouse epithelial cells to a secretory lineage was time- and dose-dependent. Anti-tumour efficacy was associated with cell cycle arrest and apoptosis that was in part due to Notch-dependent regulation of mitochondrial homeostasis.

CONCLUSIONS AND IMPLICATIONS

Intermittent but potent inhibition of Notch signalling is sufficient for anti-tumour efficacy in these T-ALL models. These findings provide support for the use of GSI in Notch-dependent malignancies and that clinical benefits may be derived from transient but potent inhibition of Notch.

Vistonuridine: An orally administered, life-saving antidote for 5-fluorouracil (5FU) overdose

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Background: 5FU is widely used to treat solid tumors and is often administered via infusion pump at or near its maximum tolerated dose (MTD). Toxicities and even death can occur in patients over-exposed to 5FU. Uridine is a direct biochemical antagonist of 5FU toxicity; uridine nucleotides dilute intracellular fluorouridine nucleotides derived from 5FU, reducing their lethal incorporation into RNA. However, uridine is poorly bioavailable (7%) and is therefore not a clinically viable antidote. Vistonuridine is an orally administered prodrug of uridine that delivers approximately 8-fold more uridine than administration of uridine itself. Methods: 17 patients overdosed with 5FU have been treated with vistonuridine as an antidote. Patients received vistonuridine (10g q6h for 20 doses) beginning 8 to 96 hours after overdose. Data from 13 patients with similar 5FU overdoses provide the time course and outcomes for patients receiving available supportive care without vistonuridine. A severity score, integrating dose and infusion rate, was calculated for all the patients, and this tool could be used by healthcare workers to determine the expected severity and outcome of a 5FU overdose. Results: All 17 overdose patients treated with vistonuridine recovered fully. Most, especially those for whom vistonuridine treatment was initiated sooner, had relatively modest toxicity. In marked contrast, all 11 of the literature-reported cases of 5FU overdose for which an outcome of death would have been predicted died from the overdose despite receiving available supportive care. Conclusions: These clinical data illustrate the serious, debilitating and life threatening nature of 5FU overdose and the current lack of effective treatments. Vistonuridine appears to be a safe and effective, life-saving antidote to 5FU overdose.

[Table: see text]

Clinical trial: dexlansoprazole MR, a proton pump inhibitor with dual delayed-release technology, effectively controls symptoms and prevents relapse in patients with healed erosive oesophagitis

BACKGROUND

Dexlansoprazole MR heals all grades of erosive oesophagitis (EO).

AIM

To assess efficacy and safety of dexlansoprazole MR in maintaining healed EO and heartburn relief.

METHODS

In this randomized, double-blind trial, 445 patients with healed EO received dexlansoprazole MR 30 mg or 60 mg or placebo once daily for 6 months. This trial assessed maintenance of endoscopic healing (primary endpoint) and continued symptom relief based on daily diaries (secondary endpoints).

RESULTS

Dexlansoprazole MR 30 mg and 60 mg were superior to placebo for maintaining healed EO (P < 0.0025; Hochberg's). By life-table analysis, maintenance rates were 75%, 83% and 27% for dexlansoprazole MR 30 mg, 60 mg and placebo respectively. Crude maintenance rates were 66% for both dexlansoprazole MR doses and 14% for placebo. Dexlansoprazole MR controlled heartburn (medians of 91-96% for 24-h heartburn-free days, 96-99% for heartburn-free nights). The only more common adverse event occurring at a significantly higher rate in dexlansoprazole MR groups than placebo when analysed per patient-months of exposure was upper respiratory tract infection.

CONCLUSIONS

Dexlansoprazole MR effectively maintained EO healing and symptom relief; most patients were heartburn-free for >90% of days. Both doses were well tolerated.

Socio-demographic and geographic analysis of overweight and obesity in Canadian adults using the Canadian Community Health Survey (2005)

Using the 2005 Canadian Community Health Survey, this study examined how overweight and obesity in Canadian adults are distributed across socio-demographic and geographic groupings. Overweight and obesity prevalence were modeled against socio-demographic indicators using Poisson regression and were assessed geographically using choropleth maps. The Gini coefficient was used to assess the distribution of prevalence across risk groups. The potential impacts of high risk versus population-based prevention approaches on the population prevalence of obesity were also examined. Of adults aged 25 to 64 years, 17% were obese and 53% were overweight or obese, with the highest proportions observed in older age groups, among those who were physically inactive, white or non-immigrant, with low educational levels, and living in the prairie and east coast regions. Recalculation of obesity rates under the different prevention scenarios demonstrated that population-based approaches could achieve a four-fold greater decrease in obesity cases than high risk approaches, highlighting the need for broader population strategies for obesity prevention in Canada.

EUS and clinical characteristics of cystic pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) may rarely appear as cystic or mixed solid-cystic masses. The endoscopic ultrasound (EUS) morphology and cyst fluid characteristics of these tumors are not well clarified. We retrospectively identified nine adult patients with nine single cystic pancreatic neuroendocrine tumors (CNETs). These nine included 0.67 % of the 1344 patients with pancreatic cystic lesions and 9.5 % of the 95 confirmed PNETs evaluated over the 12-year study period. At presentation, four patients were asymptomatic and five had known acute pancreatitis (n = 2), MEN-1 syndrome with hypoglycemia (n = 1), and abdominal pain (n = 2). Median maximal tumor diameter was 26 mm (range 20 - 64 mm). EUS morphology was mixed solid and cystic (n = 4) or cystic alone (n = 5). Cytology from EUS-fine-needle aspiration (FNA) (median 2 passes; range 1 - 6) demonstrated a PNET, and immunocytochemistry was confirmatory in all patients. Cyst fluid carcinoembryonic antigen (CEA) (n = 4) and amylase (n = 5) ranged from 0.1 to 1.8 ng/ml (normal 0 - 2.5 ng/ml) and 72 to 1838 U/L (normal 25 - 161 U/L), respectively. Six patients underwent surgery, and the preoperative diagnosis was confirmed in all.

The role of collectives in STI and HIV/AIDS prevention among female sex workers in Karnataka, India

This paper evaluates the role of female sex worker (FSW) collectives in the state of Karnataka, India, regarding their facilitating effect in increasing knowledge and promoting change towards safer sexual behaviour. In 2002 a state-wide survey of FSWs was administered to a stratified sample of 1,512 women. Following the survey, a collectivization index was developed to measure the degree of involvement of FSWs in collective-related activities. The results indicate that a higher degree of collectivization was associated with increased knowledge and higher reported condom use. Reported condom use was higher with commercial clients than with regular partners or husbands among all women and a gradient was observed in most outcome variables between women with low, medium and high collectivization index scores. Collectivization seems to have a positive impact in increasing knowledge and in empowering FSWs in Karnataka to adopt safer sex practices, particularly with commercial clients. While these results are encouraging, they may be confounded by social desirability, selection and other biases. More longitudinal and qualitative studies are required to better understand the nature of sex worker collectives and the benefits that they can provide.

Accumulation of oxidized lipid-protein complexes alters phagosome maturation in retinal pigment epithelium

Lipid peroxidation has been implicated in many age-associated disorders including macular degeneration of the retina. We sought to elucidate the mechanism by which accumulation of oxidized LDL (oxLDL) reduces the ability of retinal pigment epithelium (RPE) to process photoreceptor outer segments (OS) as a model of peroxidation-induced disruption of phagocytosis. OxLDL did not reduce the lysosomal hydrolytic capacity of the RPE, but efficiently inhibited processing of various internalized proteins. OxLDL caused a delay in the acquisition of late lysosomal markers by newly formed phagosomes. At the same time, an excessive accumulation of markers of early phagosomal compartments was also observed. The activity of phosphatidylinositol 3-kinase (PI3K) was reduced in phagosomes of the RPE treated with oxLDL. These results suggest that accumulation of oxidized lipid-protein complexes in the RPE impedes phagosome maturation by blocking PI3K recruitment to the phagosomal membrane, leading to delayed processing of internalized OS.

The effect of low versus high dose of streptozotocin in cynomolgus monkeys (Macaca fascilularis)

Streptozotocin (STZ) is often used to induce diabetes in animal models. However, morbidity associated with STZ and its ability to induce diabetes vary with different dosages among different animal species, including nonhuman primates. To find an optimal dose of STZ that would cause diabetes with minimal toxicity, we compared low and high doses of STZ. Male cynomolgus monkeys (3-6 years old) were given a single dose of 100 mg/kg (high dose, 4 animals) or 55 mg/kg (low dose, 20 animals) of STZ. Blood glucose levels, intravenous glucose tolerance test (IVGTT), pancreatic biopsies, liver function tests (LFTs), liver biopsies, kidney function tests, and kidney biopsies were performed periodically. Animals from both groups developed diabetes within 24 h after administration of STZ. Serum C-peptide levels in both groups decreased from 2 to 8 ng/mL before STZ to between 0.01 and 0.6 ng/mL after STZ. Animals with the high dose of STZ developed transient vomiting within minutes after injection. During the first week after STZ injection, high-dose animals developed elevated LFTs, BUN and creatinine. In contrast, low-dose animals had normal liver and kidney function tests. Histological analysis showed that animals given the high dose of STZ developed marked steatosis of the liver and tubular injury in the kidneys, whereas animals given the low dose of STZ had normal-looking liver and kidney histology. The pancreatic islets in both groups were indistinguishable by immunoperoxidase staining for insulin, and showed either no insulin-positive cells or rare insulin-positive cells. Glucagon staining was normal. Over time, low-dose diabetic monkeys remained persistently hyperglycemic with negligible C-peptide stimulation by intravenous glucose. We conclude that low-dose STZ at 55 mg/mL successfully induces diabetes in cynomolgus monkeys with minimal liver and kidney toxicity.

Adult porcine islet transplantation in baboons treated with conventional immunosuppression or a non-myeloablative regimen and CD154 blockade

The aim of the present study was to assess the survival of adult porcine islets transplanted into baboons receiving either (I) conventional triple drug immunosuppressive therapy or (2) a non-myeloablative regimen and an anti-CD154 monoclonal antibody (mAb) aimed at tolerance-induction. Group 1 baboons (n = 3) were pancreatectomized prior to intraportal injection of 10,000 porcine islet equivalents (IE)/kg and immunosuppressed with anti-thymocyte globulin (ATG), cyclosporine and azathioprine. In Group 2 (n = 2), non-pancreatectomized baboons underwent induction therapy with whole body and thymic irradiation, and ATG. Extracorporeal immunoadsorption (EIA) of anti-Galalpha1,3Gal (Gal) antibody was carried out. Maintenance therapy was with cobra venom factor, cyclosporine. mycophenolate mofetil, methylprednisolone and anti-CD154 mAb. Porcine islets were injected intraportally (14,000 and 32,000 IE/kg, respectively) and high-dose pig mobilized peripheral blood progenitor cells (3 x 10(10) cells/kg) were infused into a systemic vein. Porcine islets were also implanted in the sternomastoid muscle to facilitate subsequent biopsies. In both groups. porcine C-peptide was measured, and histological examination of liver or sternomastoid muscle biopsies was performed at regular intervals. In Group 1, total pancreatectomy reduccd human C-peptide to < 0.1 ng/ml and induced insulin-requiring diabetes. The transplantation of porcine islets was followed by normalization of glycemia for 15-24 h. Porcine C-peptide was detected only transiently immediately after porcine islet injection (maximum 0.12 ng/ml). Histological examination of liver biopsies taken between days 2 and 19 did not reveal viable islets, but necrotic cell structures with mononuclear cell infiltrates were identified in portal venules. In Group 2, injection of porcine islets into non-pancreatectomized recipients induced a transient hypoglycemia (2-4 h) requiring concentrated intravenous dextrose administration. Porcine C-peptide was detectable for 5 and 3 days (maximum 2.8 and 1.0 ng/ml), respectively. Baboon #4 died on day 12 from small bowel intussusception. Liver and sternomastoid muscle biopsies showed well-preserved porcine islets, staining positive for insulin and glucacon, without signs of rejection. In baboon #5, viable islets were detected in the sternomastoid muscle biopsy on day 14, but not on day 28 or thereafter. A progressive mononuclear cell and macrophage infiltration was seen in the biopsies. In conclusion, conventional immunosuppression allowed survival of porcine islets in baboons for < 24 h. The non-myeloablative regimen prolonged survival of porcine islets for > 14 days. However, despite depletion of T cells, anti-Gal antibody and complement, and CD154-hlockade, porcine islets were rejected by day 28. These results suggest that powerful innate immune responses are involved in rejection of discordant xenogencic islets.

The DNA binding activity of TAL-1 is not required to induce leukemia/lymphoma in mice

Activation of the basic helix-loop-helix (bHLH) gene TAL-1 (or SCL) is the most frequent gain-of-function mutation in pediatric T cell acute lymphoblastic leukemia (T-ALL). Similarly, mis-expression of tal-1 in the thymus of transgenic mice results in the development of clonal T cell lymphoblastic leukemia. To determine the mechanism(s) of tal-1-induced leukemogenesis, we created transgenic mice expressing a DNA binding mutant of tal-1. Surprisingly, these mice develop disease, demonstrating that the DNA binding properties of tal-1 are not required to induce leukemia/lymphoma in mice. However, wild type tal-1 and the DNA binding mutant both form stable complexes with E2A proteins. In addition, tal-1 stimulates differentiation of CD8-single positive thymocytes but inhibits the development of CD4-single positive cells: effects also observed in E2A-deficient mice. Our study suggests that the bHLH protein tal-1 contributes to leukemia by interfering with E2A protein function(s).

ENCORE: the effect of nutrient enrichment on coral reefs. Synthesis of results and conclusions

Coral reef degradation resulting from nutrient enrichment of coastal waters is of increasing global concern. Although effects of nutrients on coral reef organisms have been demonstrated in the laboratory, there is little direct evidence of nutrient effects on coral reef biota in situ. The ENCORE experiment investigated responses of coral reef organisms and processes to controlled additions of dissolved inorganic nitrogen (N) and/or phosphorus (P) on an offshore reef (One Tree Island) at the southern end of the Great Barrier Reef, Australia. A multi-disciplinary team assessed a variety of factors focusing on nutrient dynamics and biotic responses. A controlled and replicated experiment was conducted over two years using twelve small patch reefs ponded at low tide by a coral rim. Treatments included three control reefs (no nutrient addition) and three + N reefs (NH4Cl added), three + P reefs (KH2PO4 added), and three + N + P reefs. Nutrients were added as pulses at each low tide (ca twice per day) by remotely operated units. There were two phases of nutrient additions. During the initial, low-loading phase of the experiment nutrient pulses (mean dose = 11.5 microM NH4+; 2.3 microM PO4(-3)) rapidly declined, reaching near-background levels (mean = 0.9 microM NH4+; 0.5 microM PO4(-3)) within 2-3 h. A variety of biotic processes, assessed over a year during this initial nutrient loading phase, were not significantly affected, with the exception of coral reproduction, which was affected in all nutrient treatments. In Acropora longicyathus and A. aspera, fewer successfully developed embryos were formed, and in A. longicyathus fertilization rates and lipid levels decreased. In the second, high-loading, phase of ENCORE an increased nutrient dosage (mean dose = 36.2 microM NH4+; 5.1 microM PO4(-3)) declining to means of 11.3 microM NH4+ and 2.4 microM PO4(-3) at the end of low tide) was used for a further year, and a variety of significant biotic responses occurred. Encrusting algae incorporated virtually none of the added nutrients. Organisms containing endosymbiotic zooxanthellae (corals and giant clams) assimilated dissolved nutrients rapidly and were responsive to added nutrients. Coral mortality, not detected during the initial low-loading phase, became evident with increased nutrient dosage, particularly in Pocillopora damicornis. Nitrogen additions stunted coral growth, and phosphorus additions had a variable effect. Coral calcification rate and linear extension increased in the presence of added phosphorus but skeletal density was reduced, making corals more susceptible to breakage. Settlement of all coral larvae was reduced in nitrogen treatments, yet settlement of larvae from brooded species was enhanced in phosphorus treatments. Recruitment of stomatopods, benthic crustaceans living in coral rubble, was reduced in nitrogen and nitrogen plus phosphorus treatments. Grazing rates and reproductive effort of various fish species were not affected by the nutrient treatments. Microbial nitrogen transformations in sediments were responsive to nutrient loading with nitrogen fixation significantly increased in phosphorus treatments and denitrification increased in all treatments to which nitrogen had been added. Rates of bioerosion and grazing showed no significant effects of added nutrients. ENCORE has shown that reef organisms and processes investigated in situ were impacted by elevated nutrients. Impacts were dependent on dose level, whether nitrogen and/or phosphorus were elevated and were often species-specific. The impacts were generally sub-lethal and subtle and the treated reefs at the end of the experiment were visually similar to control reefs. Rapid nutrient uptake indicates that nutrient concentrations alone are not adequate to assess nutrient condition of reefs. Sensitive and quantifiable biological indicators need to be developed for coral reef ecosystems. The potential bioindicators identified in ENCORE should be tested in future research on coral reef/nutrient interactions. Synergistic and cumulative effects of elevated nutrients and other environmental parameters, comparative studies of intact vs. disturbed reefs, offshore vs. inshore reefs, or the ability of a nutrient-stressed reef to respond to natural disturbances require elucidation. An expanded understanding of coral reef responses to anthropogenic impacts is necessary, particularly regarding the subtle, sub-lethal effects detected in the ENCORE studies.

Macrophage receptors responsible for distinct recognition of low density lipoprotein containing pyrrole or pyridinium adducts: models of oxidized low density lipoprotein

Oxidation of low density lipoproteins (LDL) induced by incubation with Cu(2+) ions results in the formation of a heterogeneous group of aldehydic adducts on lysyl residues (Lys) of apolipoprotein B (apoB) that are thought to be responsible for the uptake of oxidized LDL (oxLDL) by macrophages. To define the structural and chemical criteria governing such cell recognition, we induced two modifications of lysines in LDL that mimic prototypic adducts present in oxLDL; namely, epsilon-amino charge-neutralizing pyrrolation by treatment with 2,5-hexanedione (hdLDL), and epsilon-amino charge-retaining pyridinium formation via treatment with 2,4,6-trimethylpyrylium (tmpLDL). Both modifications led to recognition by receptors on mouse peritoneal macrophages (MPM). To assess whether the murine scavenger receptor class A-I (mSR-A) was responsible for recognition of hdLDL or tmpLDL in MPM, we measured binding at 4 degrees C and degradation at 37 degrees C of these modified forms of (125)I-labeled LDL by mSR-A-transfected CHO cells. Although uptake and degradation of hdLDL by mSR-A-transfected CHO cells was quantitatively similar to that of the positive control, acLDL, tmpLDL was not recognized by these cells. However, both tmpLDL and hdLDL were recognized by 293 cells that had been transfected with CD36. In the human monocytic cell line THP-1 that had been activated with PMA, uptake of tmpLDL was significantly inhibited by blocking monoclonal antibodies to CD36, further suggesting recognition of tmpLDL by this receptor. Macrophage uptake and degradation of LDL oxidized by brief exposure to Cu(2+) was inhibited more effectively by excess tmpLDL and hdLDL than was more extensively oxidized LDL, consistent with the recognition of the former by CD36 and the latter primarily by SR-A.Collectively, these studies suggest that formation of specific pyrrole adducts on LDL leads to recognition by both the mSR-A and mouse homolog of CD36 expressed on MPM, while formation of specific pyridinium adducts on LDL leads to recognition by the mouse homolog of CD 36 but not by mSR-A. As such, these two modifications of LDL may represent useful models for dissecting the relative contributions of specific modifications on LDL produced during oxidation, to the cellular uptake of this heterogeneous ligand.

Sequestration and inhibition of Daxx-mediated transcriptional repression by PML

PML fuses with retinoic acid receptor alpha (RARalpha) in the t(15;17) translocation that causes acute promyelocytic leukemia (APL). In addition to localizing diffusely throughout the nucleoplasm, PML mainly resides in discrete nuclear structures known as PML oncogenic domains (PODs), which are disrupted in APL and spinocellular ataxia cells. We isolated the Fas-binding protein Daxx as a PML-interacting protein in a yeast two-hybrid screen. Biochemical and immunofluorescence analyses reveal that Daxx is a nuclear protein that interacts and colocalizes with PML in the PODs. Reporter gene assay shows that Daxx drastically represses basal transcription, likely by recruiting histone deacetylases. PML, but not its oncogenic fusion PML-RARalpha, inhibits the repressor function of Daxx. In addition, SUMO-1 modification of PML is required for sequestration of Daxx to the PODs and for efficient inhibition of Daxx-mediated transcriptional repression. Consistently, Daxx is found at condensed chromatin in cells that lack PML. These data suggest that Daxx is a novel nuclear protein bearing transcriptional repressor activity that may be regulated by interaction with PML.

Relationship among antioxidant activity, vasodilation capacity, and phenolic content of red wines

The relationship among antioxidant activity, based on the electron-spin resonance determination of the reduction of Fremy's radical, vasodilation activity, and phenolic content was investigated in 16 red wines. The wines were selected to provide a range of origins, grape varieties, and vinification methods. Sensitive and selective HPLC methods were used for the analysis of the major phenolics in red wine: free and conjugated myricetin, quercetin, kaempferol, and isorhamnetin; (+)-catechin, (-)-epicatechin, gallic acid, p-coumaric acid, caffeic acid, caftaric acid, trans-resveratrol, cis-resveratrol, and trans-resveratrol glucoside. Total anthocyanins were measured using a colorimetric assay. The total phenolic content of the wines was determined according to the Folin-Ciocalteu colorimetric assay and also by the cumulative measurements obtained by HPLC. The 16 wines exhibited a wide range in the values of all parameters investigated. However, the total phenol contents, measured both by HPLC and colorimetrically, correlated very strongly with the antioxidant activity and vasodilation activity. In addition, the antioxidant activity was associated with gallic acid, total resveratrol, and total catechin. In contrast, only the total anthocyanins were correlated with vasodilation activity. The results demonstrate that the different phenolic profiles of wines can produce varying antioxidant and vasodilatant activities, which opens up the possibility that some red wines may provide enhanced health benefits for the consumer.

Amphetamine acts within the medial basal forebrain to initiate and maintain alert waking

Amphetamine-like stimulants exert well-known arousal-enhancing actions. Surprisingly, little is known concerning the neuroanatomical substrates through which these drugs enhance arousal. Previous work implicates a number of basal forebrain structures in the regulation of behavioral state. The current studies examined the effects of amphetamine infusions made directly within basal forebrain sites on behavioral, electroencephalographic, and electromyographic indices of arousal in anesthetized and unanesthetized rat. In the anesthetized rat, amphetamine elicited prolonged epochs of bilateral electroencephalographic activation when infused unilaterally (3.75 microg/150 nl) into an extended region of the medial basal forebrain, demarcated anteriorally by the anterior portion of the medial septal area (which includes posterior accumbens shell) and posteriorally by the posterior aspect of the preoptic area of the hypothalamus. In the unanesthetized (undisturbed, resting) rat, amphetamine infusions into this region elicited prolonged epochs of alert waking, which at the lowest dose (3.75 microg), qualitatively resembled normal waking. Infusions placed lateral (including within the substantia innominata), anterior (including within the core subregion of the nucleus accumbens), posterior, or dorsal to these structures, as well as directly within the lateral ventricles did not alter electroencephalographic or behavioral measures. These results indicate that a region of the medial basal forebrain, extending from the anterior medial septum/accumbens shell to the posterior preoptic area, is a site within which amphetamine-like stimulants act to enhance behavioral and electroencephalographic measures of arousal.

Protein adducts of iso[4]levuglandin E2, a product of the isoprostane pathway, in oxidized low density lipoprotein

Levuglandin (LG) E2, a cytotoxic seco prostanoic acid co-generated with prostaglandins by nonenzymatic rearrangements of the cyclooxygenase-derived endoperoxide, prostaglandin H2, avidly binds to proteins. That LGE2-protein adducts can also be generated nonenzymatically is demonstrated by their production during free radical-induced oxidation of low density lipoprotein (LDL). Like oxidized LDL, LGE2-LDL, but not native LDL, undergoes receptor-mediated uptake and impaired processing by macrophage cells. Since radical-induced lipid oxidation produces isomers of prostaglandins, isoprostanes (isoPs), via endoperoxide intermediates, we postulated previously that a similar family of LG isomers, isoLGs, is cogenerated with isoPs. Now iso[4]LGE2-protein epitopes produced by radical-induced oxidation of arachidonic acid in the presence of protein were detected with an enzyme-linked immunosorbent assay. Iso[4]LGE2-protein epitopes are also generated during free radical-induced oxidation of LDL. All of the LGE2 isomers generated upon oxidation of LDL are efficiently sequestered by covalent adduction with LDL-based amino groups. The potent electrophilic reactivity of iso-LGs can be anticipated to have biological consequences beyond their obvious potential as markers for specific arachidonate-derived protein modifications that may be of value for the quantitative assessment of oxidative injury.

Dorsal and ventral rentinoic territories defined by retinoic acid synthesis, break-down and nuclear receptor expression

Determination of the dorso-ventral dimension of the vertebrate retina is known to involve retinoic acid (RA), in that high RA activates expression of a ventral retinaldehyde dehydrogenase and low RA of a dorsal dehydrogenase. Here we show that in the early eye vesicle of the mouse embryo, expression of the dorsal dehydrogenase is preceded by, and transiently overlaps with, the RA-degrading oxidase creating a trough between very high ventral and moderately high dorsal RA levels. Most of the RA receptors are expressed uniformly throughout the retina except for the RA-sensitive RARbeta, which is down-regulated in the CYP26 stripe. The orphan receptor COUP-TFII, which modulates RA responses, colocalizes with the dorsal dehydrogenase. The organization of the embryonic vertebrate retina into dorsal ventral territories divided by a horizontal boundary has parallels to the division of the Drosophila eye disc into dorsal, equatorial and ventral zones, indicating that the similarities in eye morphogenesis extend beyond single molecules to topographical patterns.

Sternothoracotomy for combined coronary artery bypass grafting and left upper lobectomy in a patient with low-lying tracheostoma

A 64-year-old man had a low-lying tracheostoma and presented with unstable angina and a mass in the pulmonary left upper lobe. Simultaneous coronary revascularization and resection of the lung neoplasm were completed through a sternothoracotomy (clam-shell) incision. The advantages of this approach include excellent exposure to the mediastinum and the lung fields, and the option of using both internal thoracic arteries for bypass grafting.

Dorsal and ventral retinal territories defined by retinoic acid synthesis, break-down and nuclear receptor expression

Determination of the dorso-ventral dimension of the vertebrate retina is known to involve retinoic acid (RA), in that high RA activates expression of a ventral retinaldehyde dehydrogenase and low RA of a dorsal dehydrogenase. Here we show that in the early eye vesicle of the mouse embryo, expression of the dorsal dehydrogenase is preceded by, and transiently overlaps with, the RA-degrading oxidase CYP26. Subsequently in the embryonic retina, CYP26 forms a narrow horizontal boundary between the dorsal and ventral dehydrogenases, creating a trough between very high ventral and moderately high dorsal RA levels. Most of the RA receptors are expressed uniformly throughout the retina except for the RA-sensitive RARbeta, which is down-regulated in the CYP26 stripe. The orphan receptor COUP-TFII, which modulates RA responses, colocalizes with the dorsal dehydrogenase. The organization of the embryonic vertebrate retina into dorsal and ventral territories divided by a horizontal boundary has parallels to the division of the Drosophila eye disc into dorsal, equatorial and ventral zones, indicating that the similarities in eye morphogenesis extend beyond single molecules to topographical patterns.

Determining the feasibility of the Canadian First Nations and Inuit regional (longitudinal) health surveys

The general framework recommended for the First Nations Regional Health Surveys can be summarized as follows: 1. Currently committed funding from Health Canada and Human Resources Development Canada should be used to develop a framework of regional cohort studies for First Nations and Inuit people in the 10 provinces to generate information on community health and the well-being of children. Indian and Northern Affairs should consider participating on an equal basis in this initiative, as long as program dollars are not compromised, in order to assist First Nations and Inuit communities in the documentation of socioeconomic conditions associated with health and the well-being of children. Representatives of these departments should work together with Métis representatives to secure funding for a similar initiative for Métis people in the provinces. 2. National First Nations and Inuit organizations and the major funding departments should be invited to appoint members to First Nations and Inuit National Steering Committees. These Committees will be responsible for the general supervision of the development of the regional cohort studies for their respective communities. 3. Regional (usually provincial) First Nations and Inuit political organizations should be invited to submit letters of intent indicating their interest in developing the longitudinal survey on behalf of all communities in their respective regions. 4. Regional organizations should be asked to propose a research group with which they wish to collaborate in the development of the survey. Research groups should be approved by the national steering committees. 5. National steering committees should appoint a "core questions research group" that will be responsible for the development of comparative "core questions" for the longitudinal surveys. 6. A national Aboriginal technical committee should be established consisting of members of the "core question" research group and one member from all other research groups involved in the longitudinal surveys. 7. National steering committees should approve grants to each regional organization/research group to develop and implement the survey. 8. This initiative should be developed at a pace which is suitable to Aboriginal organizations and communities. It is likely that the first wave of the survey in 1996 will be restricted to several pilot projects in different parts of the country. Other regions and communities may not be ready to participate until 1998.

Cultural environmental health risk perception in the Canadian north

This paper examines perceptions of various sources of environmental health risk in one Aboriginal community in Northern Canada to better understand how community members view those risks. The central question addressed is whether there is a pattern of perception, or form of cultural rationality, that informs risk perception generally, or are health risk perceptions created in an ad hoc manner, depending on local circumstances. A case study approach, involving both ethnographic and survey methods, was employed in three aboriginal communities in Quebec, Saskatchewan, and Manitoba. This paper reports on one of those communities. Distinct cultural patterns of perception were found: a pattern that recognizes contingencies and conditions that produce dangerous circumstances--a pattern that is open to new forms of knowledge and sensitive to uncertainty.

Measurement of oxidation in plasma Lp(a) in CAPD patients using a novel ELISA

BACKGROUND

LGE2 is produced by the cyclooxygenase- or free radical-mediated modification of arachidonate and is formed during the oxidation of low density lipoprotein (LDL) with subsequent adduction to lysine residues in apo B. We have developed a sensitive enzyme-linked sandwich immunosorbent assay (ELISA) for detection and measurement of LGE2-protein adducts as an estimate of oxidation of plasma LDL and Lp(a).

METHODS

The assay employs rabbit polyclonal antibodies directed against LGE2-protein adducts that form pyrroles, and alkaline phosphatase-conjugated polyclonal antibodies specific for apo B or apo (a). It demonstrates a high degree of specificity, sensitivity and validity.

RESULTS

Epitopes characteristic for LGE2-pyrroles were quantified in patients with end-stage renal disease (ESRD) that had undergone continuous ambulatory peritoneal dialysis (CAPD) and in a gender- and age-matched control population. In addition to finding that both LDL and Lp(a) levels were elevated in CAPD patients, we also found that plasma Lp(a) but not LDL was more oxidized in CAPD patients when compared to corresponding lipoproteins from healthy subjects. Using density gradient ultra-centrifugation of plasma samples, we found that modified Lp(a) floats at the same density as total Lp(a).

CONCLUSIONS

The results of this study demonstrate that oxidation of plasma Lp(a) is a characteristic of ESRD patients undergoing CAPD. This ELISA may be useful for further investigations on oxidation of lipoproteins in the circulation of specific patient populations.

Channel specificity and secondary structure of the glucose-inducible porins of Pseudomonas spp

The OprB porin-mediated glucose transport system was investigated in Pseudomonas chlororaphis, Burkholderia cepacia, and Pseudomonas fluorescens. Kinetic studies of [U-14C]glucose uptake revealed an inducible system of low Km values (0.3-5 microM) and high specificity for glucose. OprB homologs were purified and reconstituted into proteoliposomes. The porin function and channel preference for glucose were demonstrated by liposome swelling assays. Examination of the periplasmic glucose-binding protein (GBP) components by Western immunoblotting using P. aeruginosa GBP-specific antiserum revealed some homology between P. aeruginosa GBP and periplasmic proteins from P. fluorescens and P. chlororaphis but not B. cepacia. Circular dichroism spectropolarimetry of purified OprB-like porins from the three species revealed beta sheet contents of 31-50% in agreement with 40% beta sheet content for the P. aeruginosa OprB porin. These findings suggest that the high-affinity glucose transport system is primarily specific for glucose and well conserved in the genus Pseudomonas although its outer membrane component may differ in channel architecture and specificity for other carbohydrates.

Child fatality review in Georgia: a young system demonstrates its potential for identifying preventable childhood deaths

BACKGROUND

Child fatality review (CFR) by interagency teams can contribute to the prevention of childhood deaths. We investigated the potential usefulness of Georgia's CFR, legislated in 1990 primarily to prevent death from child maltreatment, for identifying preventable deaths from injury and sudden infant death syndrome (SIDS).

METHODS

Using CFR report data and death certificate data, we examined reviewed and nonreviewed childhood deaths in Georgia in 1991 and examined data by etiology, county, risk factors, and preventability.

RESULTS

Injury or SIDS caused 33.2% of childhood deaths in Georgia in 1991; CFR reviewed 29.4% of these. Child fatality review was most sensitive for investigating death from intentional injury (40.5%) and SIDS (35.3%). Review teams reassigned the cause of five deaths (2.0%) to child abuse or neglect. County participation was low (31.4%). Overall, 29.0% of deaths were judged preventable.

CONCLUSIONS

Georgia's CFR has potential for identifying preventable childhood deaths. Refinements in the system can increase the number and accuracy of death investigations. By participating in the system, physicians may make meaningful contributions to preventing childhood death in their own communities.

Non-conventional modification of low density lipoproteins: chemical models for macrophage recognition of oxidized LDL

To define the structural and chemical criteria governing recognition of oxidized LDL (oxLDL) by mouse peritoneal macrophages (MPM), we exposed LDL to novel chemical modification agents that induce defined neutralizing and non-neutralizing alterations of lysine as models for distinct apoB adducts present in oxLDL. We found some exceptions to the usual notion that neutralization of lysine positive charges is the principal determinant governing MPM recognition. In addition, competitive binding experiments using chemically modified 125I-LDL preparations revealed that, whereas some modifications engendered recognition principally by the classical scavenger receptor class A (SRA), as seen for acetylated LDL (acLDL), chemical models of advanced aldehydic modifications of LDL led instead to MPM uptake mainly by oxLDL receptors distinct from SRA.

(Carboxyalkyl)pyrroles in human plasma and oxidized low-density lipoproteins

Free-radical oxidation of human plasma low-density lipoprotein (LDL) produces (carboxyalkyl)pyrrole (CAP) epitopes that were detected with enzyme-linked immunosorbent assays using antibodies raised against keyhole limpet hemocyanin (KLH)-bound 2-(omega-carboxyheptyl)-pyrrole (CHP) and 2-(omega-carboxypropyl)pyrrole (CPP). These antibodies exhibit high structural selectivity (< 0.5% cross-reactivity) in competitive binding inhibition assays with the corresponding human serum albumin (HSA)-bound pyrroles. No cross-reactivity was detected for HSA-bound 2-pentylpyrrole, an epitope that is generated by a reaction of 4-hydroxy-2-nonenal (HNE) with protein lysyl residues. Oxidation of either arachidonic or linoleic acid in the presence of HSA produced an HNE-derived 2-pentylpyrrole epitope. However, only oxidation of linoleic acid formed HSA-bound CHP, while only oxidation of arachidonic acid generated HSA-bound CPP. Since ester hydrolysis with KOH markedly elevated levels of immunoreactive epitopes detected in oxidized LDL, the CAPs are presumably generated by reactions of oxidized cholesteryl esters, triglycerides, and phospholipids with LDL protein, and only some of these oxidized esters are hydrolyzed, e.g., by phospholipase activity associated with LDL. Protein-bound CHP immunoreactivity was detected in human plasma, and levels are significantly elevated in renal failure and atherosclerosis patients compared with healthy volunteers. This provides the first evidence for the biological occurrence of protein-bound CAPs in vivo and further suggests that free-radical oxidation of polyunsaturated lipids produces hydroxyalkenal carboxylate esters whose gamma-hydroxy-alpha,beta-unsaturated aldehyde functionality and reactivity resemble that of HNE.