Multimodal spatial availability: A singly-constrained measure of accessibility considering multiple modes

Place-based accessibility measures communicate the potential interaction with opportunities at a zone that populations can access. Recent research has explored the implications of how opportunities are counted by different accessibility methods. In conventional measures, opportunities are multiply counted if more than one zone offers access to the same opportunity. This multi-count of opportunities leads to values of accessibility that are difficult to interpret. A possible solution to enhance the meaning-making of accessibility results is by constraining the calculations to match a known quantity. This ensures all zonal values sum up to a predetermined quantity (i.e., the total number of opportunities). In this way, each value can be meaningfully related to this total. A recent effort that implements this solution is spatial availability, a singly-constrained accessibility measure. In this paper, we extend spatial availability for use in the case of multiple modes or more generally, heterogeneous population segments with distinct travel behaviors. After deriving a multimodal version of spatial availability, we proceed to illustrate its features using a synthetic example. We then apply it to an empirical example of low emission zones in Madrid, Spain. We conclude with suggestions for future research and its use in evaluating policy interventions.

Impact of therapeutic and low volume plasma exchange on clinical laboratory parameters in patients treated for Alzheimer's disease from the AMBAR study

INTRODUCTION

Little is known about the impact of plasma exchange (PE) on clinical laboratory parameters in Alzheimer's disease (AD) patients.

METHODS

AD patients in the AMBAR trial (N = 322) received weekly therapeutic PE (TPE) for 6 weeks followed by monthly low-volume PE (LVPE) for12 months. Treatment were placebo (sham PE), low-albumin, low-albumin + IVIG (i.e., albumin alternated with intravenous immunoglobulin) and high-albumin + IVIG.

RESULTS

Coagulation parameters transiently increased post-TPE. Blood calcium, platelets, and albumin levels decreased but remained within the reference range. Leukocyte counts increased. Fibrinogen, hemoglobin, total protein, gamma globulin, and IgG, transiently dipped below the reference range. Hypogammaglobulinemia (7.2 g/L) persisted in pre-TPE measurements. No changes were observed during the LVPE period. Cerebrospinal fluid parameters and vital signs were unchanged throughout.

CONCLUSION

Laboratory parameters of AD patients were affected by TPE similarly to effects of PE-treatment for other pathologies. These effects were less pronounced or non-existent for LVPE.

Feasibility, safety, and tolerability of two modalities of plasma exchange with albumin replacement to treat elderly patients with Alzheimer's disease in the AMBAR study

BACKGROUND

In the Alzheimer Management by Albumin Replacement (AMBAR) study, mild-to-moderate Alzheimer's disease (AD) patients were treated with a plasma exchange (PE) program. Feasibility and safety of PE in this specific population are poorly understood and were analyzed in detail in this study.

METHODS

Qualified patients were treated with 6 weeks of weekly conventional therapeutic plasma exchange (TPE) with albumin replacement followed by monthly low-volume plasma exchange (LVPE) for 12 months. The patients were divided into four groups: placebo (sham PE treatment), low-albumin (20 g), low-albumin + intravenous immunoglobulin (IVIG) (10 g), and high-albumin (40 g) + IVIG (20 g). Adverse events (AEs) were recorded and analyzed for all PE treatment groups and PE modalities.

RESULTS

PE procedure-related AEs were more common in the active treatment groups (16.9% out of 1283 TPE and 12.5% out of 2203 LVPE were associated with at least one AE, a similar rate than in other PE indications) than in the placebo group (0.7% out of 1223 sham PE). Percentage of procedures with at least one AEs was higher with central venous access compared to peripheral venous access in all three active treatment groups (20.1% vs 13.1%, respectively).

CONCLUSION

The TPE and LVPE procedures used in the AMBAR study on mild-to-moderate AD population were as safe and feasible as in other therapeutic applications of PE or routine plasmapheresis.

Introducing spatial availability, a singly-constrained measure of competitive accessibility

Accessibility indicators are widely used in transportation, urban and healthcare planning, among many other applications. These measures are weighted sums of reachable opportunities from a given origin, conditional on the cost of movement, and are estimates of the potential for spatial interaction. Over time, various proposals have been forwarded to improve their interpretability: one of those methodological additions have been the introduction of competition. In this paper we focus on competition, but first demonstrate how a widely used measure of accessibility with congestion fails to properly match the opportunity-seeking population. We then propose an alternative formulation of accessibility with competition, a measure we call spatial availability. This measure relies on proportional allocation balancing factors (friction of distance and population competition) that are equivalent to imposing a single constraint on conventional gravity-based accessibility. In other words, the proportional allocation of opportunities results in a spatially available opportunities value which is assigned to each origin that, when all origin values are summed, equals the total number of opportunities in the region. We also demonstrate how Two-Stage Floating Catchment Area (2SFCA) methods are equivalent to spatial availability and can be reconceptualized as singly-constrained accessibility. To illustrate the application of spatial availability and compare it to other relevant measures, we use data from the 2016 Transportation Tomorrow Survey of the Greater Golden Horseshoe area in southern Ontario, Canada. Spatial availability is an important contribution since it clarifies the interpretation of accessibility with competition and paves the way for future applications in equity analysis (e.g., spatial mismatch, opportunity benchmarking, policy intervention scenario analysis).

Neuroimaging analyses from a randomized, controlled study to evaluate plasma exchange with albumin replacement in mild-to-moderate Alzheimer's disease: additional results from the AMBAR study

PURPOSE

This study was designed to detect structural and functional brain changes in Alzheimer's disease (AD) patients treated with therapeutic plasma exchange (PE) with albumin replacement, as part of the recent AMBAR phase 2b/3 clinical trial.

METHODS

Mild-to-moderate AD patients were randomized into four arms: three arms receiving PE with albumin (one with low-dose albumin, and two with low/high doses of albumin alternated with IVIG), and a placebo (sham PE) arm. All arms underwent 6 weeks of weekly conventional PE followed by 12 months of monthly low-volume PE. Magnetic resonance imaging (MRI) volumetric analyses and regional and statistical parametric mapping (SPM) analysis on 18F-fluorodeoxyglucose positron emission tomography (18FDG-PET) were performed.

RESULTS

MRI analyses (n = 198 patients) of selected subcortical structures showed fewer volume changes from baseline to final visit in the high albumin + IVIG treatment group (p < 0.05 in 3 structures vs. 4 to 9 in other groups). The high albumin + IVIG group showed no statistically significant reduction of right hippocampus. SPM 18FDG-PET analyses (n = 213 patients) showed a worsening of metabolic activity in the specific areas affected in AD (posterior cingulate, precuneus, and parieto-temporal regions). The high-albumin + IVIG treatment group showed the greatest metabolic stability over the course of the study, i.e., the smallest percent decline in metabolism (MaskAD), and least progression of defect compared to placebo.

CONCLUSIONS

PE with albumin replacement was associated with fewer deleterious changes in subcortical structures and less metabolic decline compared to the typical of the progression of AD. This effect was more marked in the group treated with high albumin + IVIG.

TRIAL REGISTRATION

(AMBAR trial registration: EudraCT#: 2011-001,598-25; ClinicalTrials.gov ID: NCT01561053).

Children's Access to Non-School Destinations by Active or Independent Travel: A Scoping Review

BACKGROUND

Children's access to non-school destinations is important for their well-being, but this has been overlooked in transport planning. Research on children's access to non-school destinations is growing, and there is a need for a comprehensive overview, examining both quantitative and qualitative studies, of the existing evidence on places that children access by active or independent travel.

OBJECTIVES

Identify and summarize quantitative and qualitative research on the topic of active or independent travel to non-school destinations for elementary aged children (6 to 13 years old).

METHODS

Papers published in English between 1980 and July 2021 were sourced from: (i) Web of Science Core Collection; (ii) PubMed; and (iii) APA PsycInfo. Three relevant journals related to children and transport were hand searched: (i) Children's Geographies; (ii) Journal of Transport & Health; and (iii) Journal of Transport Geography. The search was limited to peer-reviewed articles published in English between 1980 and July 2021. Covidence, an online software platform for systematic reviews, was used to organize articles during the title and abstract screening stage. PRISMA-Scr is applied for reporting.

RESULTS

27 papers were retained from an initial 1293 identified peer-reviewed articles. The results reveal that children in different geographies travel unsupervised or by active modes to places that support different domains of their well-being such as a friend or relative's home, local parks or green spaces, recreational facilities, and different retail locations (e.g., restaurants). There is evidence that children's ability to reach certain places is constrained, likely due to safety concerns or environmental barriers.

CONCLUSIONS

Research on children's diverse destinations is relatively limited as compared to trips to school. Various methodologies have been applied and can be combined to completement each other such as objective GPS tracking and subjective surveys on places children would go if they were available. Future research should clearly report and discuss the non-school destinations that children access to better inform transport planning and policy for all aspects of children's lives.

Optimizing the Definition of Ischemic Core in CT Perfusion: Influence of Infarct Growth and Tissue-Specific Thresholds

BACKGROUND AND PURPOSE

CTP allows estimating ischemic core in patients with acute stroke. However, these estimations have limited accuracy compared with MR imaging. We studied the effect of applying WM- and GM-specific thresholds and analyzed the infarct growth from baseline imaging to reperfusion.

MATERIALS AND METHODS

This was a single-center cohort of consecutive patients (n = 113) with witnessed strokes due to proximal carotid territory occlusions with baseline CT perfusion, complete reperfusion, and follow-up DWI. We segmented GM and WM, coregistered CTP with DWI, and compared the accuracy of the different predictions for each voxel on DWI through receiver operating characteristic analysis. We assessed the yield of different relative CBF thresholds to predict the final infarct volume and an estimated infarct growth-corrected volume (subtracting the infarct growth from baseline imaging to complete reperfusion) for a single relative CBF threshold and GM- and WM-specific thresholds.

RESULTS

The fixed threshold underestimated lesions in GM and overestimated them in WM. Double GM- and WM-specific thresholds of relative CBF were superior to fixed thresholds in predicting infarcted voxels. The closest estimations of the infarct on DWI were based on a relative CBF of 25% for a single threshold, 35% for GM, and 20% for WM, and they decreased when correcting for infarct growth: 20% for a single threshold, 25% for GM, and 15% for WM. The combination of 25% for GM and 15% for WM yielded the best prediction.

CONCLUSIONS

GM- and WM-specific thresholds result in different estimations of ischemic core in CTP and increase the global accuracy. More restrictive thresholds better estimate the actual extent of the infarcted tissue.

Neuropsychological, neuropsychiatric, and quality-of-life assessments in Alzheimer's disease patients treated with plasma exchange with albumin replacement from the randomized AMBAR study

INTRODUCTION

We report the effects of plasma exchange (PE) with albumin replacement on neuropsychological, neuropsychiatric, and quality-of-life (QoL) outcomes in mild-to-moderate Alzheimer's disease (AD) patients in a phase 2b/3 trial (Alzheimer's Management by Albumin Replacement [AMBAR] study).

METHODS

Three hundred forty-seven patients were randomized into placebo (sham-PE) and three PE-treatment arms with low/high doses of albumin, with/without intravenous immunoglobulin (IVIG). Specific test measurements were performed at baseline; month 2 (weekly conventional PE); months 6, 9, and 12 (monthly low-volume PE [LVPE]); and month 14.

RESULTS

The PE-treated mild-AD cohort improved their language fluency and processing speed versus placebo at month 14 (effect sizes: >100%; P-values: .03 to .001). The moderate-AD cohort significantly improved short-term verbal memory (effect sizes: 94% to >100%; P-values: .02 to .003). The progression of the neuropsychiatric symptoms of PE-treated was similar to placebo. Mild-AD patients showed improved QoL (P-values: .04 to .008).

DISCUSSION

PE-treated AD patients showed improvement in memory, language abilities, processing speed, and QoL-AD. No worsening of their psychoaffective status was observed.

Plasma exchange with albumin replacement and disease progression in amyotrophic lateral sclerosis: a pilot study

Background

Plasma exchange (PE) is used to treat a range of neurological disorders. Based on results demonstrated in Alzheimer’s disease, we theorized that PE with albumin replacement (PE-A) might alter the metabolic profile of plasma and cerebrospinal fluid in patients with amyotrophic lateral sclerosis (ALS) by removing disease-inducing molecules. The aim of this study was to evaluate the effect of PE-A on disease progression in ALS.

Methods

In this open-label, non-controlled, single-arm, prospective pilot study, 13 adults with ALS had 6 months’ treatment with PE-A 5% and 6 months’ follow-up. Primary endpoints were changes from baseline in the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) score and forced vital capacity (FVC) through 48 weeks. A post hoc analysis compared individual patient data with the expected ALSFRS-R progression slope.

Results

The median ALSFRS-R score declined throughout the study, although the rate of decline was slower than expected in seven patients at treatment end and in five patients at study end. Six patients remained in the same baseline slope progression category, and four patients improved their slope category at treatment end. Median FVC decreased significantly during the study. Treatment was well tolerated. Of 330 PE-A procedures, 0.9% were associated with potentially related adverse events.

Conclusion

Although functional impairment progressed, about two-thirds of patients showed a slower than expected rate of decline at treatment end. Most patients had unaltered (54.5%) or reduced (36.4%) ALSFRS-R slope progression at treatment end. Further evaluation of PE-A in controlled studies involving more patients is warranted.

EudraCT number

2013-004842-40.

Trial registration

ClinicalTrials.gov identifier: NCT02479802.

Changes in accessibility to emergency and community food services during COVID-19 and implications for low income populations in Hamilton, Ontario

In this paper we analyze the changes in accessibility to emergency and community food services before and during the COVID-19 pandemic in the City of Hamilton, Ontario. Many of these food services are the last line of support for households facing food insecurity; as such, their relevance cannot be ignored in the midst of the economic upheaval caused by the pandemic. Our analysis is based on the application of balanced floating catchment areas and concentrates on households with lower incomes (<CAD40,000, approximately the Low Income Cutoff Value for a city of Hamilton's size). We find that accessibility was low to begin with in suburban and exurban parts of the city; furthermore, about 14% of locations originally available in Hamilton closed during the pandemic, further reducing accessibility. The impact of closures on the level of service of the remaining facilities, and on accessibility, was disproportionate, with system-wide losses exceeding 39%. Those losses were geographically and demographically uneven. While every part of the city faced a reduction in accessibility, inner suburbs fared worse in terms of loss of accessibility. As well, children (age ≤18) appear to have been impacted the most.

Therapeutic plasma exchange with albumin: a new approach to treat Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) is a chronic neurodegenerative disease and the most common cause of dementia. It has a complex pathophysiology that is not yet completely understood, where multiple central, systemic, and environmental factors play a key role in disease progression. Understanding the multifactorial nature of AD is paramount to formulate new therapies.

AREAS COVERED

The authors reviewed the role of the amyloid-β-binding, antioxidant, and immunomodulatory properties of albumin in AD and the use of therapeutic plasma exchange (PE) in neurology. The results from the Alzheimer Management By Albumin Replacement (AMBAR) trial that combined the use of PE with albumin replacement in patients with mild-to-moderate AD, are also analyzed.

EXPERT OPINION

Findings from the AMBAR study provide encouraging results in the treatment of AD with PE and albumin replacement, especially in patients at the moderate stage of the disease, who showed less cognitive decline from baseline compared with placebo in most of the variables analyzed. Further research is warranted to ascertain the possible mechanisms of action underlying these results. Different cohorts of patients that may also benefit from this treatment, such as those with mild cognitive impairment or other types of dementia, could also be the target of additional studies.

Emerging insights into the role of albumin with plasma exchange in Alzheimer's disease management

Alzheimer's disease (AD) is a neurodegenerative process that inexorably leads to progressive deterioration of cognition function and, ultimately, death. Central pathophysiologic features of AD include the accumulation of extracellular plaques comprised of amyloid-β peptide (Aβ) and the presence of intraneuronal neurofibrillary tangles. However, a large body of evidence suggests that oxidative stress and inflammation are major contributors to the pathogenesis and progression of AD. To date, available pharmacologic treatments are only symptomatic. Clinical trials focused on amyloid and non-amyloid-targeted treatments with small molecule pharmacotherapy and immunotherapies have accumulated a long list of failures. Considering that around 90 % of the circulating Aβ is bound to albumin, and that a dynamic equilibrium exists between peripheral and central Aβ, plasma exchange with albumin replacement has emerged as a new approach in a multitargeted AD therapeutic strategy (AMBAR Program). In plasma exchange, a patient's plasma is removed by plasmapheresis to eliminate toxic endogenous substances, including Aβ and functionally impaired albumin. The fluid replacement used is therapeutic albumin, which acts not only as a plasma volume expander but also has numerous pleiotropic functions (e.g., circulating Aβ- binding capacity, transporter, detoxifier, antioxidant) that are clinically relevant for the treatment of AD. Positive results from the AMBAR Program (phase 1, 2, an 2b/3 trials), i.e., slower decline or stabilization of disease symptoms in the most relevant clinical efficacy and safety endpoints, offer a glimmer of hope to both AD patients and caregivers.

Safety and tolerability of GRF6019 in mild-to-moderate Alzheimer's disease dementia

INTRODUCTION

This phase 2 trial evaluated the safety, tolerability, and feasibility of repeated infusions of the plasma fraction GRF6019 in mild-to-moderate Alzheimer's disease.

METHODS

In this randomized, double-blind, dose-comparison trial, 47 patients were randomized 1:1 to receive daily infusions of 100 mL (n = 24) or 250 mL (n = 23) of GRF6019 for 5 consecutive days over two dosing periods separated by a treatment-free interval of 3 months.

RESULTS

The mean (standard deviation [SD]) age of the enrolled patients was 74.3 (6.9), and 62% were women. Most adverse events (55%) were mild, with no clinically significant differences in safety or tolerability between the two dose levels. The mean (SD) baseline Mini-Mental State Examination score was 20.6 (3.7) in the 100 mL group and 19.6 (3.7) in the 250 mL group; at 24 weeks, the within-patient mean change from baseline was -1.0 points (95% confidence interval [CI], -3.1 to 1.1) in the 100 mL group and +1.5 points (95% CI, -0.4 to 3.3) in the 250 mL group. The within-patient mean change from baseline on the Alzheimer's Disease Assessment Scale-Cognitive subscale was -0.4 points (95% CI, -2.9 to 2.2) in the 100 mL group, while in the 250 mL group it was -0.9 points (95% CI, -3.0 to 1.2). The within-patient mean change from baseline on the Alzheimer's Disease Cooperative Study-Activities of Daily Living was -0.7 points in the 100 mL group (95% CI, -4.3 to 3.0) and -1.3 points (95% CI, -3.4 to 0.7) in the 250 mL group. The mean change from baseline on the Category Fluency Test, Clinical Dementia Rating Scale-Sum of Boxes, Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change, and Neuropsychiatric Inventory Questionnaire was similar for both treatment groups and did not show any worsening.

DISCUSSION

GRF6019 was safe and well tolerated, and patients experienced no cognitive decline and minimal functional decline. These results support further development of GRF6019.

A randomized, controlled clinical trial of plasma exchange with albumin replacement for Alzheimer's disease: Primary results of the AMBAR Study

Introduction

This phase 2b/3 trial examined the effects of plasma exchange (PE) in patients with mild‐to‐moderate Alzheimer's disease (AD).

Methods

Three hundred forty‐seven patients (496 screened) were randomized (1:1:1:1) into three PE treatment arms with different doses of albumin and intravenous immunoglobulin replacement (6‐week period of weekly conventional PE followed by a 12‐month period of monthly low‐volume PE), and placebo (sham).

Results

PE‐treated patients performed significantly better than placebo for the co‐primary endpoints: change from baseline of Alzheimer's Disease Cooperative Study–Activities of Daily Living (ADCS‐ADL; P = .03; 52% less decline) with a trend for Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS‐Cog; P = .06; 66% less decline) scores at month 14. Moderate‐AD patients (baseline Mini‐Mental State Examination [MMSE] 18‐21) scored better on ADCS‐ADL (P = .002) and ADAS‐Cog (P = .05), 61% less decline both. There were no changes in mild‐AD patients (MMSE 22‐26). PE‐treated patients scored better on the Clinical Dementia Rating Sum of Boxes (CDR‐sb) (P = .002; 71% less decline) and Alzheimer's Disease Cooperative Study‐Clinical Global Impression of Change (ADCS‐CGIC) (P < .0001; 100% less decline) scales.

Discussion

This trial suggests that PE with albumin replacement could slow cognitive and functional decline in AD, although further studies are warranted.

Effects of Albumin Treatment on Systemic and Portal Hemodynamics and Systemic Inflammation in Patients With Decompensated Cirrhosis

BACKGROUND & AIMS

We investigated the effect of albumin treatment (20% solution) on hypoalbuminemia, cardiocirculatory dysfunction, portal hypertension, and systemic inflammation in patients with decompensated cirrhosis with and without bacterial infections.

METHODS

We performed a prospective study to assess the effects of long-term (12 weeks) treatment with low doses (1 g/kg body weight every 2 weeks) and high doses (1.5 g/kg every week) of albumin on serum albumin, plasma renin, cardiocirculatory function, portal pressure, and plasma levels of cytokines, collecting data from 18 patients without bacterial infections (the Pilot-PRECIOSA study). We also assessed the effect of short-term (1 week) treatment with antibiotics alone vs the combination of albumin plus antibiotics (1.5 g/kg on day 1 and 1 g/kg on day 3) on plasma levels of cytokines in biobanked samples from 78 patients with bacterial infections included in a randomized controlled trial (INFECIR-2 study).

RESULTS

Circulatory dysfunction and systemic inflammation were extremely unstable in many patients included in the Pilot-PRECIOSA study; these patients had intense and reversible peaks in plasma levels of renin and interleukin 6. Long-term high-dose albumin, but not low-dose albumin, was associated with normalization of serum level of albumin, improved stability of the circulation and left ventricular function, and reduced plasma levels of cytokines (interleukin 6, granulocyte colony-stimulating factor, interleukin 1 receptor antagonist, and vascular endothelial growth factor) without significant changes in portal pressure. The immune-modulatory effects of albumin observed in the Pilot-PRECIOSA study were confirmed in the INFECIR-2 study. In this study, patients given albumin had significant reductions in plasma levels of cytokines.

CONCLUSIONS

In an analysis of data from 2 trials (Pilot-PRECIOSA study and INFECIR-2 study), we found that albumin treatment reduced systemic inflammation and cardiocirculatory dysfunction in patients with decompensated cirrhosis. These effects might be responsible for the beneficial effects of albumin therapy on outcomes of patients with decompensated cirrhosis. ClinicalTrials.gov, Numbers: NCT00968695 and NCT03451292.

Plasma exchange for Alzheimer's disease Management by Albumin Replacement (AMBAR) trial: Study design and progress

Introduction

Preliminary studies have shown that treatment with plasma exchange (PE) plus therapeutic albumin replacement in patients with Alzheimer's disease (AD) induced mobilization of plasma and cerebrospinal fluid amyloid β protein, associated with an improvement in memory and language functions, as well as the stabilization of brain perfusion, which persisted after treatment discontinuation.

Methods

Alzheimer's Management By Albumin Replacement (AMBAR) is a multicenter, randomized, blinded and placebo-controlled, parallel-group, phase IIb/III trial enrolling patients with mild to moderate AD. The study evaluates PE with different replacement volumes of therapeutic albumin (5% and 20% Albutein®, Grifols), with or without intravenous immunoglobulin (Flebogamma® 5% DIF, Grifols). Patients are randomized to one of three active treatment groups or one control (sham PE) group (1:1:1:1). The intervention regime includes a first 6-week stage of intensive treatment, followed by a second 12-month stage of maintenance treatment. The change from the baseline to the end of treatment periods in the ADAS-Cog and ADCS-ADL scores are the coprimary efficacy variables. Secondary efficacy variables include change from the baseline in scores on cognitive, functional, behavioral, and overall progression tests; changes in plasma and cerebrospinal fluid levels of amyloid β and tau protein; and assessment of structural and functional changes in brain areas of interest. Safety and tolerability are assessed.

Results

The study has enrolled 496 patients from 41 centers (19 in Spain and 22 in the USA); 347 of these patients were randomized and underwent close to 5000 PEs, of which approximately 25% were sham PEs.

Discussion

We present an innovative approach for treating AD. The study has been designed to demonstrate clinical efficacy, defined as slow decline of the patient's cognition and brain function. The sample size has adequate power to detect differences between any of the active treatment groups and the control group, as well as between the three active treatment groups combined and the control group.

•

AMBAR approaches Alzheimer's disease with plasma exchange plus albumin replacement.

•

Clinical efficacy is to slow decline of the patient's cognition and brain function.

•

Sample size has power to detect differences between treatments and controls.

•

Interim results showed a safety profile similar to other plasma exchange indications.

Efficacy and safety of Niuliva® immune globulin to prevent hepatitis B reinfection in de novo orthotopic liver transplant

Aims: To determine efficacy and safety of intravenous hepatitis B immune globulin (Niuliva®, Grifols) to prevent reinfection in de novo orthotopic liver transplantation. Patients & methods: In a nonrandomized, noncontrolled and Phase III clinical trial, 15 adult patients (12 men) were treated with Niuliva from the anhepatic phase (10,000 IU/daily 1 week postsurgery) up to 6 or 12 months (5000 IU/weekly 1 month; 5000 IU/monthly thereafter). Results: No patients showed reinfection throughout the study. Niuliva was effective in maintaining antibody titers above the thresholds recommended by the European Medicines Agency (EMA) to prevent reinfection (100–150 IU/l). Four serious adverse events were reported in three patients (none related to the study product). There were no seroconversions and no deaths. Conclusion: Long-term, high-dose Niuliva administration was safe and effective to prevent graft reinfection in the tested patients.

An imbalance in the T-helper phenotypes displayed by senescent CD4+CD28null T cells is associated with erosive arthritis (rhupus syndrome) in systemic lupus erythematosus

OBJECTIVE

The objective was to assess the proportion of Th1, Th2 and Th17 phenotypes in senescent CD4⁺CD28^null cells from patients with systemic lupus erythematosus (SLE) and its association with the pattern of joint involvement.

METHODS

This cross-sectional study was performed in SLE patients with erosive arthritis (rhupus) or nondeforming, nonerosive arthritis. Total CD4⁺CD28^null cells as well as the proportion of these cells expressing T-bet, GATA3 or RORγt were analyzed by color-flow cytometry. Serum osteopontin levels were measured by ELISA.

RESULTS

Eighteen SLE patients (nine with rhupus and nine with nonerosive arthritis) were studied. The percentage of CD4⁺CD28^null/CD4⁺ cells (17.7%, 10.3-25.0% versus 9.4%, 8.1-22.4%; P = 0.386) as well as the osteopontin levels (5800, 5,134-5995 pg/ml versus 5578, 5171-5717 pg/ml; P > 0.05) were similar in both groups. A higher percentage of CD4⁺CD28^nullT-bet⁺ cells (42.8%, 33.5-53.4% versus 30.0%, 23.3-34.2%) but a lower percentage of CD4⁺CD28^nullGATA3⁺ cells (3.1%, 1.7-5.6% versus 6.2%, 2.6-18.4%) was observed in patients with rhupus than in their counterparts ( P = 0.016). The frequency of CD4⁺CD28^nullRORγt⁺ cells was similar between groups.

CONCLUSIONS

In patients with rhupus, senescent CD4⁺CD28^null cells are preferentially polarized to a Th1 phenotype, whereas this is partial towards Th2 in lupus patients with a nonerosive arthritis pattern.

Longitudinal Neuroimaging Analysis in Mild-Moderate Alzheimer's Disease Patients Treated with Plasma Exchange with 5% Human Albumin

Background:

Recently, modifications of Aβ_1-42 levels in CSF and plasma associated with improvement in memory and language functions have been observed in patients with mild-moderate Alzheimer’s disease (AD) treated with plasma exchange (PE) with albumin replacement.

Objective:

To detect structural and functional brain changes in PE-treated AD patients as part of a Phase II clinical trial.

Methods:

Patients received between 3 and 18 PE with albumin (Albutein^® 5%, Grifols) or sham-PE (controls) for 21 weeks (divided in one intensive and two maintenance periods) followed by 6-month follow-up. Brain perfusion assessed by SPECT scans using an automated software (NeuroGam^®) and brain structural changes assessed by MRI were performed at weeks 0 (baseline), 21, and 44 (with additional SPECT at weeks 9 and 33). Statistical parametric mapping (voxel-based analysis, SPM) and Z-scores calculations were applied to investigate changes to baseline.

Results:

42 patients were recruited (39 evaluable; 37 analyzed: 18 PE-treated; 19 controls). There was a trend toward decreasing hippocampi and total intracranial volume for both patient groups during the study (p < 0.05). After six months, PE-treated patients had less cerebral perfusion loss than controls in frontal, temporal, and parietal areas, and perfusion stabilization in Brodmann area BA38-R during the PE-treatment period (p < 0.05). SPM analysis showed stabilization or absence of progression of perfusion loss in PE-treated patients until week 21, not observed in controls.

Conclusions:

Mild-moderate AD patients showed decreased brain volume and impairment of brain perfusion as expected for the progression of the disease. PE-treatment with albumin replacement favored the stabilization of perfusion.

Efficacy and Safety of Plasma Exchange with 5% Albumin to Modify Cerebrospinal Fluid and Plasma Amyloid-β Concentrations and Cognition Outcomes in Alzheimer's Disease Patients: A Multicenter, Randomized, Controlled Clinical Trial

Background: Studies conducted in animal models and humans suggest the presence of a dynamic equilibrium of amyloid-β (Aβ) peptide between cerebrospinal fluid (CSF) and plasma compartments.

Objective: To determine whether plasma exchange (PE) with albumin replacement was able to modify Aβ concentrations in CSF and plasma as well as to improve cognition in patients with mild-moderate Alzheimer’s disease (AD).

Methods: In a multicenter, randomized, patient- and rater-blind, controlled, parallel-group, phase II study, 42 AD patients were assigned (1 : 1) to PE treatment or control (sham) groups. Treated patients received a maximum of 18 PE with 5% albumin (Albutein^®, Grifols) with three different schedules: two PE/weekly (three weeks), one PE/weekly (six weeks), and one PE/bi- weekly (12 weeks), plus a six-month follow-up period. Plasma and CSF Aβ_1–40 and Aβ_1–42 levels, as well as cognitive, functional, and behavioral measures were determined.

Results: CSF Aβ_1–42 levels after the last PE compared to baseline were marginally higher in PE-treated group versus controls (adjusted means of variation: 75.3 versus –45.5 pg/mL; 95% CI: –19.8, 170.5 versus 135.1, 44.2; p = 0.072). Plasma Aβ_1–42 levels were lower in the PE-treated group after each treatment period (p < 0.05). Plasma Aβ_1–40 levels showed a saw-tooth pattern variation associated with PE. PE-treated patients scored better in the Boston Naming Test and Semantic Verbal Fluency (p < 0.05) throughout the study. Neuropsychiatric Inventory scores were higher in controls during the PE phase (p < 0.05).

Conclusion: PE with human albumin modified CSF and plasma Aβ_1–42 levels. Patients treated with PE showed improvement in memory and language functions, which persisted after PE was discontinued.

Travel behavior of low income older adults and implementation of an accessibility calculator

Given the aging demographic landscape, the concept of walkable neighborhoods has emerged as a topic of interest, especially during the last decade. However, we know very little about whether walkable neighborhoods promote walking among older adults, particularly those with lower incomes. Therefore in this paper we: (i) examine the relation between trip distance and sociodemographic attributes and accessibility features of lower income older adults in Metro Vancouver; and, (ii) implement a web-based application to calculate the accessibility of lower income older adults in Metro Vancouver based on their travel behavior. We use multilevel linear regression to estimate the determinants of trip length. We find that in this population distance traveled is associated with gender, living arrangements, and dog ownership. Furthermore, significant geographical variations (measured using a trend surface) were also found. To better visualize the impact of travel behavior on accessibility by personal profile and location, we also implemented a web-based calculator that generates an Accessibility (A)-score using Google Maps API v3 that can be used to evaluate the accessibility of neighborhoods from the perspective of older adults.

Cost-effectiveness of prostate cancer screening: a simulation study based on ERSPC data

BACKGROUND

The results of the European Randomized Study of Screening for Prostate Cancer (ERSPC) trial showed a statistically significant 29% prostate cancer mortality reduction for the men screened in the intervention arm and a 23% negative impact on the life-years gained because of quality of life. However, alternative prostate-specific antigen (PSA) screening strategies for the population may exist, optimizing the effects on mortality reduction, quality of life, overdiagnosis, and costs.

METHODS

Based on data of the ERSPC trial, we predicted the numbers of prostate cancers diagnosed, prostate cancer deaths averted, life-years and quality-adjusted life-years (QALY) gained, and cost-effectiveness of 68 screening strategies starting at age 55 years, with a PSA threshold of 3, using microsimulation modeling. The screening strategies varied by age to stop screening and screening interval (one to 14 years or once in a lifetime screens), and therefore number of tests.

RESULTS

Screening at short intervals of three years or less was more cost-effective than using longer intervals. Screening at ages 55 to 59 years with two-year intervals had an incremental cost-effectiveness ratio of $73000 per QALY gained and was considered optimal. With this strategy, lifetime prostate cancer mortality reduction was predicted as 13%, and 33% of the screen-detected cancers were overdiagnosed. When better quality of life for the post-treatment period could be achieved, an older age of 65 to 72 years for ending screening was obtained.

CONCLUSION

Prostate cancer screening can be cost-effective when it is limited to two or three screens between ages 55 to 59 years. Screening above age 63 years is less cost-effective because of loss of QALYs because of overdiagnosis.

Treatment of Alzheimer disease using combination therapy with plasma exchange and haemapheresis with albumin and intravenous immunoglobulin: Rationale and treatment approach of the AMBAR (Alzheimer Management By Albumin Replacement) study

INTRODUCTION

There is a growing interest in new therapeutic strategies for the treatment of Alzheimer disease (AD) which focus on reducing the beta-amyloid peptide (Aβ) burden in the brain by sequestering plasma Aβ, a large proportion of which is bound to albumin and other proteins. This review discusses the concepts of interaction between Aβ and albumin that have given rise to AMBAR (Alzheimer's Disease Management by Albumin Replacement) project, a new multicentre, randomised, controlled clinical trial for the treatment of AD.

DEVELOPMENT

Results from preliminary research suggest that Albutein(®) (therapeutic albumin, Grifols) contains no quantifiable levels of Aβ. Studies also show that Albutein(®) has Aβ binding capacity. On the other hand, AD entails a high level of nitro-oxidative stress associated with fibrillar aggregates of Aβ that can induce albumin modification, thus affecting its biological functions. Results from the phase ii study confirm that using therapeutic apheresis to replace endogenous albumin with Albutein(®) 5% is feasible and safe in patients with AD. This process resulted in mobilisation of Aβ and cognitive improvement in treated patients. The AMBAR study will test combination therapy with therapeutic apheresis and haemopheresis with the possible leverage effect of Albutein(®) with intravenous immunoglobulin replacement (Flebogamma(®) DIF). Cognitive, functional, and behavioural changes in patients with mild to moderate AD will be assessed.

CONCLUSIONS

the AMBAR study represents a new therapeutic perspective for AD.

Compliance potential mapping: a tool to assess potential contributions of walking towards physical activity guidelines

BACKGROUND

Walking for transport is increasingly considered an important component for meeting physical activity guidelines. This is true for individuals of all ages, and particularly important for seniors, for whom other physical activities may not be recommended. In order to evaluate the potential contributions of walking to physical activity, in this paper the concept of Compliance Potential Mapping is introduced. The concept is illustrated using seniors as a case study.

METHODS

Based on estimates of walking trip distance and frequency, estimates of expected total daily walking distance are obtained. These estimates are converted to weekly walking minutes, which are in turn compared to recommended physical activity guidelines for seniors. Once estimates of travel behavior are available, the approach is straightforward and based on relatively simple map algebra operations.

RESULTS

Compliance Potential Mapping as a tool to assess the potential contributions of walking towards physical activity is demonstrated using data from Montreal's 2008 travel survey. The results indicate that the central parts of Montreal Island display higher potential for compliance with physical activity guidelines, but with variations according to age, income, occupation, possession of driver's license and vehicle, and neighborhood and accessibility parameters.

CONCLUSIONS

Compliance Potential Maps offer valuable information for public health and transportation planning and policy analysis.

Prostate cancer incidence and mortality in the Spanish section of the European Randomized Study of Screening for Prostate Cancer (ERSPC)

BACKGROUND

To present the long-term results of a prostate cancer (PC) screening trial conducted in a Mediterranean setting.

METHODS

A total of 4276 men aged 45-70 years were randomized to screening arm (PSA test performed) and control arm (no tests). Transrectal ultrasonography-guided sextant prostate biopsy was conducted when PSA > or = 3 ng ml(-1). Date and cause of death were retrieved from death certificates. PC incidence, and disease-specific and overall mortality curves were plotted and comparison between arms was made. Analysis of causes of death was also performed.

RESULTS

Median age at randomization was 57.0 years. Median follow-up time was 15.2 years. A total of 241 men were diagnosed with PC, 161 (6.7%) in the screening arm and 80 (4.3%) in the control arm (P<0.01). Eventually, 554 men (13%) died. No difference in all-cause mortality was found between arms (P=0.34). Only 10 men (10/4276, 0.23%) died from PC, no differences between arms (P=0.67). Overall, the main causes of death were malignancy (54.2%), cardiovascular (17.9%) and respiratory (9.2%) diseases. Main cancer causes of death were lung and bronchus cancer (37.2%), colorectum (15.0%) and stomach (9.0%) cancer. PC only accounted for 3.0% of all malignant causes of death (ranked 10th).

CONCLUSIONS

Our study failed to demonstrate benefits of PC screening in terms of all-cause and PC-specific mortality after a median follow-up of 15 years. The limited sample size and the low long-term PC mortality observed in our setting were probably the most important factors to explain these results.

[Natural history of lumbar disc hernias: does gadolinium enhancement have any prognostic value?]

OBJECTIVES

To evaluate the percentage of disc hernias that have disappeared after one year of follow-up and the time to disappearance. To determine whether gadolinium enhancement is useful for predicting whether the hernia will disappear. To analyze whether the pattern of enhancement can help predict whether the fragment will disappear.

MATERIAL AND METHODS

This prospective study included 118 patients with acute symptoms of lumbosciatica and a herniated disc diagnosed by CT. In 72 patients, we performed gadolinium-enhanced MRI every 6 months for one year or until the herniation disappeared; we related the findings of protrusion, extrusion, and the enhancement pattern with the disappearance or persistence of herniated disc material. We analyzed the results with univariate and multivariate statistics.

RESULTS

The 59% of the hernias disappeared within 1 year of follow-up and 66% disappeared within the first 8 months of follow-up. The 83% of the extruded hernias disappeared, and this was significant in the multivariate analysis (P<.005). The absence of enhancement was significantly associated with the persistence of the hernia in the univariate analysis. The enhancement pattern was not useful for predicting whether the hernia would disappear. Five hernias disappeared within the first two months.

CONCLUSIONS

A high percentage of disc hernias disappear. We found a significant association between extrusion and disappearance but no correlation between the pattern of gadolinium uptake and the disappearance of the hernia.

[Obesity as risk factor for lithiasic recurrence]

OBJECTIVES

Obese patients may have special characteristics in the urinary stones formed, as the body mass index (BMI) may also be a predictive factor in lithiasic recurrence. We aim to evaluate and compare the lithiasic characteristics according to the different BMI categories, also considering the likelihood of lithiasic recurrence in presence of age and gender covariables.

MATERIAL AND METHODS

Retrospective, cross-sectional analysis on 346 lithiasic patients, 96 (27.7%) had low-normal weight, 151 (43.6%) overweight, and 99 (28.6%) obesity. The Chi-square and ANOVA tests were used. Survival analysis for the calculation of likelihood of lithiasic recurrence (yes/no) was made based on time on 158 patients in whom complete resolution of the initial stone was achieved by the Kaplan Meier method. Comparisons between the different categories of BMI were made using the log-Rank, Breslow and Tarone-Ware tests. Multivariate analysis was also made with the Cox regression model, introducing the covariables of age and gender.

RESULTS

A significant growing linear tendency has been demonstrated between multiplicity and BMI (p=0.03). The variables size and composition did not show significant differences between the groups. Median follow-up of 158 patients included in the survival analysis was 1866 days (95% CI 1602.5-2129.5). Eighteen (11.4%) of them recurred, without finding significant differences between groups: 4 low-normal weight (9.8%), 10 overweight (14.1%) and 4 obese (8.7%). The multivariate analysis also did not show a significant influence of the BMI on lithiasic recurrence (p=0.86; HR =1.06; 95% CI: 0.56-2.03).

CONCLUSION

A significant influence of BMI was shown on lithiasic multiplicity on diagnosis, although not on lithiasic recurrence based on time. It seems to be necessary to carry out studies in larger samples to calculate the true influence of BMI on lithiasic recurrence.

Measuring Ethnic Clustering and Exposure with the Q statistic: An Exploratory Analysis of Irish, Germans, and Yankees in 1880 Newark

The study of population patterns has animated a large body of urban social research over the years. An important part of this literature is concerned with the identification and measurement of segregation patterns. Recently, emphatic calls have been made to develop measures that are better able to capture the geography of population patterns. The objective of this paper is to demonstrate the application of the Q statistic, developed for the analysis of spatial association of qualitative variables, to the detection of ethnic clustering and exposure patterns. The application is to historical data from 1880 Newark in the United States, with individuals classified by ethnicity and geo-coded by place of residence. Three ethnic groups, termed Irish, Germans, and Yankees are considered. Exploratory analysis with the Q statistic identifies significant differences in the tendency of individuals and building occupancy to cluster by ethnicity. In particular, there is evidence of a strong affinity within ethnic clusters, and some intermingling between Yankee and Irish residents. In contrast, the exposure of Germans to individuals of other groups is found to be more limited.

[99mTc-OCTREOTIDE in patients with neuroendocrine tumors from the GI tract]

INTRODUCTION

It has been demonstrated that scintigraphy with somatostatin analogues is useful for the diagnosis, staging and follow up of patients with neuroendocrine tumors from the gastrointestinal tract (NET-GIT). Some studies suggest that the use of 99mTc-Hydrazinonicotinyl-Tyr3-octreotide (99mTc-HYNIC-TOC) yields similar diagnostic results than the use of 111In-DTPA-octreotide.

OBJECTIVE

To determine the clinical value of scintigraphy using 99mTc-HYNIC-TOC for the detection of primary and secondary lesions in patients with NET-GIT.

METHODS

From September 2004 to May 2009, 32 patients (17 women, age range 18 to 82 years old) with histologically proven or clinically suspected NET-GIT underwent scintigraphy using 99mTc-HYNIC-TOC Patients underwent a whole body scan, with additional static images of abdomen and pelvis, followed by SPECT at 4-hrs post injection of 925 MBq of the tracer. Patients underwent clinical, imaging and histopathology follow-up during 3 to 18 months.

RESULTS

Histopathology demonstrated carcinoid tumor in 20 patients, insulinoma in 2, gastrinoma in 2 and non-specific NET-GIT in 6. Total sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 87%, 100%, 100%, 89% and 94%, respectively. To detect the primary lesion, the values were 94%, 100% 100%, 94% and 97%, respectively and to detect secondary lesions, 79%, 100%, 100%, 86% and 91%, respectively.

CONCLUSIONS

99mTc-HYNIC-TOC is a specific somatostatin analog, with high affinity to receptor subtype SST-2, widely available and affordable by Latin American countries. It has a good performance to be used for diagnosis, staging and follow-up of patients with NET-GIT.

A Discrete-Choice Approach to Modeling Social Influence on Individual Decision Making

Individual decision making is commonly studied using discrete choice models. Models of this type are applied extensively to the study of travel behavior, residential location, and employment decisions, among other topics of interest. A notable characteristic of the underlying economic theory is the assumption that individuals seek to maximize utility on the basis of their personal attributes and the attributes of the alternatives available to them. This approach ignores the interrelated nature of decision making in social situations—in other words, the role that social structures play in shaping behavior. In this paper we describe a multinomial discrete choice approach to analyzing individual behavior in social situations where position in a social network may encourage or discourage different courses of action. By means of a simulation example, we explore some properties of the model, in particular the effect of network topology.