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1.  HIV-1 DNA Is Detected in Bone Marrow Populations Containing CD4+ T Cells but Is not Found in Purified CD34+ Hematopoietic Progenitor Cells in Most Patients on Antiretroviral Therapy 
The Journal of Infectious Diseases  2012;205(6):1014-1018.
Identifying cellular reservoirs of human immunodeficiency virus type 1 (HIV-1) in patients on antiretroviral therapy (ART) is critical to finding a cure for HIV-1. In addition to resting CD4+ T cells, CD34+ hematopoietic progenitor cells have been proposed as another reservoir. We obtained bone marrow aspirates from 11 patients on ART who had undetectable plasma HIV-1 RNA. HIV-1 DNA was detected in CD4+ T cells from peripheral blood in all patients and from bone marrow cellular fractions containing T cells in most patients. We did not find HIV-1 DNA in highly purified CD34+ populations using either a sensitive real-time polymerase chain reaction assay or a coculture assay for replication-competent HIV-1.
doi:10.1093/infdis/jir884
PMCID: PMC3282572  PMID: 22275402
2.  A comparison of item response theory-based methods for examining differential item functioning in object naming test by language of assessment among older Latinos 
Object naming tests are commonly included in neuropsychological test batteries. Differential item functioning (DIF) in these tests due to cultural and language differences may compromise the validity of cognitive measures in diverse populations. We evaluated 26 object naming items for DIF due to Spanish and English language translations among Latinos (n=1,159), mean age of 70.5 years old (Standard Deviation (SD)±7.2), using the following four item response theory-based approaches: Mplus/Multiple Indicator, Multiple Causes (Mplus/MIMIC; Muthén & Muthén, 1998–2011), Item Response Theory Likelihood Ratio Differential Item Functioning (IRTLRDIF/MULTILOG; Thissen, 1991, 2001), difwithpar/Parscale (Crane, Gibbons, Jolley, & van Belle, 2006; Muraki & Bock, 2003), and Differential Functioning of Items and Tests/MULTILOG (DFIT/MULTILOG; Flowers, Oshima, & Raju, 1999; Thissen, 1991). Overall, there was moderate to near perfect agreement across methods. Fourteen items were found to exhibit DIF and 5 items observed consistently across all methods, which were more likely to be answered correctly by individuals tested in Spanish after controlling for overall ability.
PMCID: PMC3588164  PMID: 23471423
Item response theory; differential item functioning; object naming test; Hispanic/Latinos; Spanish
3.  Cancer Stem Cells - Relevance to Clinical Transplantation 
Current Opinion in Oncology  2012;24(2):170-175.
Purpose of Review
Despite blood or marrow transplantation (BMT) being arguably the most active modality against hematologic malignancies, relapses remain the major reason for failure. Many cancers have now been shown to harbor cells that are phenotypically and biologically similar to normal cells with self-renewal capacity; these so-called cancer stem cells (CSCs) typically constitute only a small fraction of the total tumor burden, but are hypothesized to be responsible for relapse after conventional-dose therapy. Here, we review whether CSCs may have relevance to BMT.
Recent Findings
CSCs appear to be relatively resistant to standard anticancer therapies in vitro. The often dramatic responses induced by chemotherapy in most hematologic malignancies are likely a consequence of their impressive activity against the bulk tumor cells. Although the clinical importance of CSCs remains unproven, new evidence suggests that the limited durability of many of these responses reflect resistant CSCs. It is possible that CSCs are also relatively resistant to both high-dose myeloablative conditioning and allogeneic graft-versus-tumor effects. Data on the ability of most hematologic CSCs to circulate even early in the natural history of a malignancy, also raises concerns about contamination of autografts contributing to relapse.
Summary
Emerging data for the first time suggest CSCs may be responsible for relapse, even after BMT. However, BMT may be a particularly compelling setting to test CSC-targeting strategies, because it provides the most effective clinical debulking of hematologic malignancies and because CSC-targeting strategies may also enhance allogeneic antitumor immunity.
doi:10.1097/CCO.0b013e32834ec015
PMCID: PMC3312799  PMID: 22314617
Cancer stem cells; transplantation; leukemia; lymphoma; multiple myeloma
4.  Selecting optimal screening items for delirium: an application of item response theory 
Background
Delirium (acute confusion), is a common, morbid, and costly complication of acute illness in older adults. Yet, researchers and clinicians lack short, efficient, and sensitive case identification tools for delirium. Though the Confusion Assessment Method (CAM) is the most widely used algorithm for delirium, the existing assessments that operationalize the CAM algorithm may be too long or complicated for routine clinical use. Item response theory (IRT) models help facilitate the development of short screening tools for use in clinical applications or research studies. This study utilizes IRT to identify a reduced set of optimally performing screening indicators for the four CAM features of delirium.
Methods
Older adults were screened for enrollment in a large scale delirium study conducted in Boston-area post-acute facilities (n = 4,598). Trained interviewers conducted a structured delirium assessment that culminated in rating the presence or absence of four features of delirium based on the CAM. A pool of 135 indicators from established cognitive testing and delirium assessment tools were assigned by an expert panel into two indicator sets per CAM feature representing (a) direct interview questions, including cognitive testing, and (b) interviewer observations. We used IRT models to identify the best items to screen for each feature of delirium.
Results
We identified 10 dimensions and chose up to five indicators per dimension. Preference was given to items with peak psychometric information in the latent trait region relevant for screening for delirium. The final set of 48 indicators, derived from 39 items, maintains fidelity to clinical constructs of delirium and maximizes psychometric information relevant for screening.
Conclusions
We identified optimal indicators from a large item pool to screen for delirium. The selected indicators maintain fidelity to clinical constructs of delirium while maximizing psychometric information important for screening. This reduced item set facilitates development of short screening tools suitable for use in clinical applications or research studies. This study represents the first step in the establishment of an item bank for delirium screening with potential questions for clinical researchers to select from and tailor according to their research objectives.
doi:10.1186/1471-2288-13-8
PMCID: PMC3598414  PMID: 23339752
Confusion assessment method; Delirium screening; Dimensionality; Factor analysis; Item response theory; Item bank
5.  Repeated treatment with high dose cyclophosphamide for severe autoimmune diseases 
High dose cyclophosphamide (HiCY) without stem cell rescue has been shown to induce remissions in patients with severe autoimmune disorders (SADS). However, up to 80% of these patients ultimately relapse. Here we review the outcomes of seven patients treated with two cycles and one patient treated with three cycles of HiCY. The diseases re-treated were scleroderma, multiple sclerosis, three patients with severe aplastic anemia (SAA), and three patients with myasthenia gravis (MG). All but two patients with SAA had received standard immunomodulatory therapy for their disease up front and had been refractory. All patients had complete hematologic recovery. Overall survival in this cohort was 100%. All patients relapsed after the initial cycle but event free survival thereafter was 93.3%. All are still in remission except two MG patients, one of whom relapsed after a severe GI infection requiring hospitalization, and the other relapsed 3 years after the second treatment and she did not respond to the third treatment. This shows that HiCY can be safely re-administered in patients with SAA and refractory SADS. The quality and duration of second remissions appears to be equal or superior to the first remission.
PMCID: PMC3555191  PMID: 23358715
Autoimmunity; cyclophosphamide; severe autoimmune diseases
6.  Cognitive Trajectories after Postoperative Delirium 
BACKGROUND
Delirium is common after cardiac surgery and may be associated with long-term changes in cognitive function. We examined postoperative delirium and the cognitive trajectory during the first year after cardiac surgery.
METHODS
We enrolled 225 patients 60 years of age or older who were planning to undergo coronary-artery bypass grafting or valve replacement. Patients were assessed preoperatively, daily during hospitalization beginning on postoperative day 2, and at 1, 6, and 12 months after surgery. Cognitive function was assessed with the use of the Mini–Mental State Examination (MMSE; score range, 0 to 30, with lower scores indicating poorer performance). Delirium was diagnosed with the use of the Confusion Assessment Method. We examined performance on the MMSE in the first year after surgery, controlling for demographic characteristics, coexisting conditions, hospital, and surgery type.
RESULTS
The 103 participants (46%) in whom delirium developed postoperatively had lower pre-operative mean MMSE scores than those in whom delirium did not develop (25.8 vs. 26.9, P<0.001). In adjusted models, those with delirium had a larger drop in cognitive function (as measured by the MMSE score) 2 days after surgery than did those without delirium (7.7 points vs. 2.1, P<0.001) and had significantly lower postoperative cognitive function than those without delirium, both at 1 month (mean MMSE score, 24.1 vs. 27.4; P<0.001) and at 1 year (25.2 vs. 27.2, P<0.001) after surgery. With adjustment for baseline differences, the between-group difference in mean MMSE scores was significant 30 days after surgery (P<0.001) but not at 6 or 12 months (P = 0.056 for both). A higher percentage of patients with delirium than those without delirium had not returned to their preoperative baseline level at 6 months (40% vs. 24%, P = 0.01), but the difference was not significant at 12 months (31% vs. 20%, P = 0.055).
CONCLUSIONS
Delirium is associated with a significant decline in cognitive ability during the first year after cardiac surgery, with a trajectory characterized by an initial decline and prolonged impairment. (Funded by the Harvard Older Americans Independence Center and others.)
doi:10.1056/NEJMoa1112923
PMCID: PMC3433229  PMID: 22762316
7.  Carbonic anhydrase IX promotes tumour growth and necrosis in vivo and inhibition enhances anti-VEGF therapy 
Clinical Cancer Research  2012;18(11):3100-3111.
Purpose
Bevacizumab, an anti-VEGFA antibody, inhibits the developing vasculature of tumours, but resistance is common. Antiangiogenic therapy induces hypoxia and we observed increased expression of hypoxia-regulated genes, including carbonic anhydrase IX (CAIX), in response to Bevacizumab treatment in xenografts. CAIX expression correlates with poor prognosis in most tumour types and with worse outcome in Bevacizumab-treated metastatic colorectal cancer patients, malignant astrocytoma and recurrent malignant glioma.
Experimental Design
We knocked-down CAIX expression by shRNA in a colon cancer (HT29) and a glioblastoma (U87) cell line which have high hypoxic-induction of CAIX, and over-expressed CAIX in HCT116 cells which has low CAIX. We investigated the effect on growth rate in 3D culture and in vivo, and examined the effect of CAIX knockdown in combination with Bevacizumab.
Results
CAIX expression was associated with increased growth rate in spheroids and in vivo. Surprisingly, CAIX expression was associated with increased necrosis and apoptosis in vivo and in vitro. We found that acidity inhibits CAIX activity over the pH range found in tumours (pK=6.84), and this may be the mechanism whereby excess acid self-limits the build-up of extracellular acid. Expression of another hypoxia inducible CA isoform, CAXII, was upregulated in 3D but not 2D culture in response to CAIX knockdown. CAIX knockdown enhanced the effect of Bevacizumab treatment, reducing tumour growth rate in vivo.
Conclusion
This work provides evidence that inhibition of the hypoxic adaptation to anti-angiogenic therapy enhances Bevacizumab treatment and highlights the value of developing small molecules or antibodies which inhibit CAIX for combination therapy.
doi:10.1158/1078-0432.CCR-11-1877
PMCID: PMC3367109  PMID: 22498007
Carbonic anhydrase IX; Bevacizumab; Hypoxia; Carbonic anhydrase XII; pH homeostasis
8.  Carbonic anhydrase IX promotes tumour growth and necrosis in vivo and inhibition enhances anti-VEGF therapy 
Purpose
Bevacizumab, an anti-VEGFA antibody, inhibits the developing vasculature of tumours, but resistance is common. Antiangiogenic therapy induces hypoxia and we observed increased expression of hypoxia-regulated genes, including carbonic anhydrase IX (CAIX), in response to Bevacizumab treatment in xenografts. CAIX expression correlates with poor prognosis in most tumour types and with worse outcome in Bevacizumab-treated metastatic colorectal cancer patients, malignant astrocytoma and recurrent malignant glioma.
Experimental Design
We knocked-down CAIX expression by shRNA in a colon cancer (HT29) and a glioblastoma (U87) cell line which have high hypoxic-induction of CAIX, and over-expressed CAIX in HCT116 cells which has low CAIX. We investigated the effect on growth rate in 3D culture and in vivo, and examined the effect of CAIX knockdown in combination with Bevacizumab.
Results
CAIX expression was associated with increased growth rate in spheroids and in vivo. Surprisingly, CAIX expression was associated with increased necrosis and apoptosis in vivo and in vitro. We found that acidity inhibits CAIX activity over the pH range found in tumours (pK=6.84), and this may be the mechanism whereby excess acid self-limits the build-up of extracellular acid. Expression of another hypoxia inducible CA isoform, CAXII, was upregulated in 3D but not 2D culture in response to CAIX knockdown. CAIX knockdown enhanced the effect of Bevacizumab treatment, reducing tumour growth rate in vivo.
Conclusion
This work provides evidence that inhibition of the hypoxic adaptation to anti-angiogenic therapy enhances Bevacizumab treatment and highlights the value of developing small molecules or antibodies which inhibit CAIX for combination therapy.
doi:10.1158/1078-0432.CCR-11-1877
PMCID: PMC3367109  PMID: 22498007
Carbonic anhydrase IX; Bevacizumab; Hypoxia; Carbonic anhydrase XII; pH homeostasis
9.  Cognitive decline in the elderly: an analysis of population heterogeneity 
Age and Ageing  2011;40(6):684-689.
Background: studies of cognitive ageing at the group level suggest that age is associated with cognitive decline; however, there may be individual differences such that not all older adults will experience cognitive decline.
Objective: to evaluate patterns of cognitive decline in a cohort of older adults initially free of dementia.
Design, setting and subjects: elderly Catholic clergy members participating in the Religious Orders Study were followed for up to 15 years. Cognitive performance was assessed annually.
Methods: performance on a composite global measure of cognition was analysed using random effects models for baseline performance and change over time. A profile mixture component was used to identify subgroups with different cognitive trajectories over the study period.
Results: from a sample of 1,049 participants (mean age 75 years), three subgroups were identified based on the distribution of baseline performance and change over time. The majority (65%) of participants belonged to a slow decline class that did not experience substantial cognitive decline over the observation period [−0.04 baseline total sample standard deviation (SD) units/year]. About 27% experienced moderate decline (−0.19 SD/year), and 8% belonged to a class experiencing rapid decline (−0.57 SD/year). A subsample analysis revealed that when substantial cognitive decline does occur, the magnitude and rate of decline is correlated with neuropathological processes.
Conclusions: in this sample, the most common pattern of cognitive decline is extremely slow, perceptible on a time scale measured by decades, not years. While in need of cross validation, these findings suggest that cognitive changes associated with ageing may be minimal and emphasise the importance of understanding the full range of age-related pathologies that may diminish brain function.
doi:10.1093/ageing/afr101
PMCID: PMC3199215  PMID: 21890481
aged; 80 and over; cognition disorders; longitudinal study; elderly
10.  First-line erlotinib in patients with advanced non-small-cell lung cancer unsuitable for chemotherapy (TOPICAL): a double-blind, placebo-controlled, phase 3 trial 
The Lancet Oncology  2012;13(11):1161-1170.
Summary
Background
Many patients with advanced non-small-cell lung cancer (NSCLC) receive only active supportive care because of poor performance status or presence of several comorbidities. We investigated whether erlotinib improves clinical outcome in these patients.
Methods
TOPICAL was a double-blind, randomised, placebo-controlled, phase 3 trial, done at 78 centres in the UK. Eligibility criteria were newly diagnosed, pathologically confirmed NSCLC; stage IIIb or IV; chemotherapy naive; no symptomatic brain metastases; deemed unsuitable for chemotherapy because of poor (≥2) Eastern Cooperative Oncology Group performance status or presence of several comorbidities, or both; and estimated life expectancy of at least 8 weeks. Patients were randomly assigned (by phone call, in a 1:1 ratio, stratified by disease stage, performance status, smoking history, and centre, block size 10) to receive oral placebo or erlotinib (150 mg per day) until disease progression or unacceptable toxicity. Investigators, clinicians, and patients were masked to assignment. The primary endpoint was overall survival. Analyses were by intention to treat, and prespecified subgroup analyses included development of a rash due to erlotinib within 28 days of starting treatment. This study is registered, number ISRCTN 77383050.
Findings
Between April 14, 2005, and April 1, 2009, we randomly assigned 350 patients to receive erlotinib and 320 to receive placebo. We followed up patients until March 31, 2011. 657 patients died; median overall survival did not differ between groups (erlotinib, 3·7 months, 95% CI 3·2–4·2, vs placebo, 3·6 months, 3·2–3·9; unadjusted hazard ratio [HR] 0·94, 95% CI 0·81–1·10, p=0·46). 59% (178 of 302) of patients assigned erlotinib and who were assessable at 1 month developed first-cycle rash, which was the only independent factor associated with overall survival. Patients with first-cycle rash had better overall survival (HR 0·76, 95% CI 0·63–0·92, p=0·0058), compared with placebo. Compared with placebo, overall survival seemed to be worse in the group that did not develop first-cycle rash (1·30, 1·05–1·61, p=0·017). Grade 3 or 4 diarrhoea was more common with erlotinib than placebo (8% [28 of 334] vs 1% [four of 313], p=0·0001), as was high-grade rash (23% [79 of 334] vs 2% [five of 313], p<0·0001); other adverse events were much the same between groups.
Interpretation
Patients with NSCLC who are deemed unsuitable for chemotherapy could be given erlotinib. Patients who develop a first-cycle rash should continue to receive erlotinib, whereas those who do not have a rash after 28 days should discontinue erlotinib, because of the possibility of decreased survival.
Funding
Cancer Research UK, Roche.
doi:10.1016/S1470-2045(12)70412-6
PMCID: PMC3488187  PMID: 23078958
11.  Automated medical literature retrieval 
The Australasian Medical Journal  2012;5(9):489-496.
Background
The constantly growing publication rate of medical research articles puts increasing pressure on medical specialists who need to be aware of the recent developments in their field. The currently used literature retrieval systems allow researchers to find specific papers; however the search task is still repetitive and time-consuming.
Aim
In this paper we describe a system that retrieves medical publications by automatically generating queries based on data from an electronic patient record. This allows the doctor to focus on medical issues and provide an improved service to the patient, with higher confidence that it is underpinned by current research.
Method
Our research prototype automatically generates query terms based on the patient record and adds weight factors for each term. Currently the patient’s age is taken into account with a fuzzy logic derived weight, and terms describing blood-related anomalies are derived from recent blood test results. Conditionally selected homonyms are used for query expansion.
The query retrieves matching records from a local index of PubMed publications and displays results in descending relevance for the given patient. Recent publications are clearly highlighted for instant recognition by the researcher.
Results
Nine medical specialists from the Royal Adelaide Hospital evaluated the system and submitted pre-trial and post-trial questionnaires. Throughout the study we received positive feedback as doctors felt the support provided by the prototype was useful, and which they would like to use in their daily routine.
Conclusion
By supporting the time-consuming task of query formulation and iterative modification as well as by presenting the search results in order of relevance for the specific patient, literature retrieval becomes part of the daily workflow of busy professionals.
doi:10.4066/AMJ.2012.1378
PMCID: PMC3477791  PMID: 23115583
Literature retrieval
12.  Conceptual and Measurement Challenges in Research on Cognitive Reserve 
Cognitive reserve, broadly conceived, encompasses aspects of brain structure and function that optimize individual performance in the presence of injury or pathology. Reserve is defined as a feature of brain structure and/or function that modifies the relationship between injury or pathology and performance on neuropsychological tasks or clinical outcomes. Reserve is challenging to study for two reasons. The first is: reserve is a hypothetical construct, and direct measures of reserve are not available. Proxy variables and latent variable models are used to attempt to operationalize reserve. The second is: in vivo measures of neuronal pathology are not widely available. It is challenging to develop and test models involving a risk factor (injury or pathology), a moderator (reserve) and an outcome (performance or clinical status) when neither the risk factor nor the moderator are measured directly. We discuss approaches for quantifying reserve with latent variable models, with emphasis on their application in the analysis of data from observational studies. Increasingly latent variable models are used to generate composites of cognitive reserve based on multiple proxies. We review the theoretical and ontological status of latent variable modeling approaches to cognitive reserve, and suggest research strategies for advancing the field.
doi:10.1017/S1355617710001748
PMCID: PMC3289742  PMID: 21411036
Cognitive reserve; Brain reserve; Latent variable; Aging; Cognition; Neuronal plasticity; Multivariate Analysis; Environment; Social Environment; Education; Social Class; Intelligence
13.  Comprehensive Binary Interaction Mapping of SH2 Domains via Fluorescence Polarization Reveals Novel Functional Diversification of ErbB Receptors 
PLoS ONE  2012;7(9):e44471.
First-generation interaction maps of Src homology 2 (SH2) domains with receptor tyrosine kinase (RTK) phosphosites have previously been generated using protein microarray (PM) technologies. Here, we developed a large-scale fluorescence polarization (FP) methodology that was able to characterize interactions between SH2 domains and ErbB receptor phosphosites with higher fidelity and sensitivity than was previously achieved with PMs. We used the FP assay to query the interaction of synthetic phosphopeptides corresponding to 89 ErbB receptor intracellular tyrosine sites against 93 human SH2 domains and 2 phosphotyrosine binding (PTB) domains. From 358,944 polarization measurements, the affinities for 1,405 unique biological interactions were determined, 83% of which are novel. In contrast to data from previous reports, our analyses suggested that ErbB2 was not more promiscuous than the other ErbB receptors. Our results showed that each receptor displays unique preferences in the affinity and location of recruited SH2 domains that may contribute to differences in downstream signaling potential. ErbB1 was enriched versus the other receptors for recruitment of domains from RAS GEFs whereas ErbB2 was enriched for recruitment of domains from tyrosine and phosphatidyl inositol phosphatases. ErbB3, the kinase inactive ErbB receptor family member, was predictably enriched for recruitment of domains from phosphatidyl inositol kinases and surprisingly, was enriched for recruitment of domains from tyrosine kinases, cytoskeletal regulatory proteins, and RHO GEFs but depleted for recruitment of domains from phosphatidyl inositol phosphatases. Many novel interactions were also observed with phosphopeptides corresponding to ErbB receptor tyrosines not previously reported to be phosphorylated by mass spectrometry, suggesting the existence of many biologically relevant RTK sites that may be phosphorylated but below the detection threshold of standard mass spectrometry procedures. This dataset represents a rich source of testable hypotheses regarding the biological mechanisms of ErbB receptors.
doi:10.1371/journal.pone.0044471
PMCID: PMC3433420  PMID: 22973453
14.  Role of allogeneic transplantation for FLT3/ITD acute myeloid leukemia: Outcomes from 133 consecutive newly-diagnosed patients from a single institution 
AML patients with FLT3/ITD mutations have an inferior survival compared to AML patients with wild-type (WT) FLT3, primarily due to an increased relapse rate. Allogeneic transplant represents a post-remission therapy that is effective at reducing the risk of relapse for many cases of poor-risk AML. Whether or not allogeneic transplant in first complete remission (CR) can improve outcomes for patients with FLT3/ITD AML remains controversial. Our institution has adopted a policy of pursuing allogeneic transplant, including the use of alternate donors, for FLT3/ITD AML patients in remission. As part of an IRB-approved study, we performed a review of the clinical data from November 1, 2004 to October 31, 2008 on all adult patients under the age of 60 presenting in consecutive fashion to the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins with newly diagnosed non-M3 AML. We followed their outcomes through August 1, 2010. During the study period, 133 previously untreated AML patients between the ages of 20 and 59 were diagnosed and received induction and consolidation therapy at our institution. Of these 133 patients, 31 (23%) harbored a FLT3/ITD mutation at diagnosis. The median OS (overall survival) from the time of diagnosis for the FLT3/ITD AML patients was compared to the OS of the entire cohort and found to be comparable (19.3 months versus 15.5 months p=0.56.) Historically, OS for FLT3/ITD AML patients is significantly worse than for AML patients lacking this mutation. However, the OS for the 31 FLT3/ITD patients reported here was comparable to the 102 patients with WT FLT3 over the same 4 year time period. One difference that might have contributed to the surprising outcomes for the FLT3/ITD group is our aggressive pursuit of allogeneic BMT in CR1 within this group (60% of FLT3/ITD vs. 17% with WT). Our single institution study of consecutively treated AML patients supports the hypothesis that allogeneic transplant in early CR1 improves the long term outcomes for FLT3/ITD AML.
doi:10.1016/j.bbmt.2011.02.003
PMCID: PMC3110512  PMID: 21324374
Stem Cell transplantation; FLT3/ITD
15.  Multiple, correlated covariates associated with differential item functioning (DIF): Accounting for language DIF when education levels differ across languages 
Ageing research  2011;2(1):19-25.
Differential item functioning (DIF) occurs when a test item has different statistical properties in subgroups, controlling for the underlying ability measured by the test. DIF assessment is necessary when evaluating measurement bias in tests used across different language groups. However, other factors such as educational attainment can differ across language groups, and DIF due to these other factors may also exist. How to conduct DIF analyses in the presence of multiple, correlated factors remains largely unexplored. This study assessed DIF related to Spanish versus English language in a 44-item object naming test. Data come from a community-based sample of 1,755 Spanish- and English-speaking older adults. We compared simultaneous accounting, a new strategy for handling differences in educational attainment across language groups, with existing methods. Compared to other methods, simultaneously accounting for language- and education-related DIF yielded salient differences in some object naming scores, particularly for Spanish speakers with at least 9 years of education. Accounting for factors that vary across language groups can be important when assessing language DIF. The use of simultaneous accounting will be relevant to other cross-cultural studies in cognition and in other fields, including health-related quality of life.
doi:10.4081/ar.2011.e4
PMCID: PMC3418868  PMID: 22900138
cognitive testing; item response theory; logistic regression; test bias; translation
16.  A Life Course Model of Cognitive Activities, Socioeconomic Status, Education, Reading Ability, and Cognition 
OBJECTIVES
To cross-sectionally quantify the contribution of proxy measures of cognitive reserve reflective of the lifespan, such as education, socioeconomic status (SES), reading ability, and cognitive activities, in explaining late-life cognition.
DESIGN
Prospective observational cohort study of aging.
SETTING
Retirement communities across the Chicago metropolitan area.
PARTICIPANTS
Nine hundred fifty-one older adults free of clinical dementia in the Rush Memory and Aging Project (aged 79 ± 8, 74% female).
MEASUREMENTS
Baseline data on multiple life course factors included early-, mid-, and late-life participation in cognitive activities; early-life and adult SES; education; and reading ability (National Adult Reading Test; NART). Path analysis quantified direct and indirect standardized effects of life course factors on global cognition and five cognitive domains (episodic memory, semantic memory, working memory, visuospatial ability, perceptual speed).
RESULTS
Adjusting for age, sex, and race, education had the strongest association with global cognition, episodic memory, semantic memory, and visuospatial ability, whereas NART (followed by education) had the strongest association with working memory. Late-life cognitive activities had the strongest association with perceptual speed, followed by education.
CONCLUSIONS
These cross-sectional findings suggest that education and reading ability are the most-robust proxy measures of cognitive reserve in relation to late-life cognition. Additional research leveraging path analysis is warranted to better understand how these life course factors, reflecting the latent construct of cognitive reserve, affect abnormal cognitive aging.
doi:10.1111/j.1532-5415.2011.03499.x
PMCID: PMC3222272  PMID: 21797830
education; cognition; reading ability; cognitive reserve
17.  A botulinum toxin–derived targeted secretion inhibitor downregulates the GH/IGF1 axis 
The Journal of Clinical Investigation  2012;122(9):3295-3306.
Botulinum neurotoxins (BoNTs) are zinc endopeptidases that block release of the neurotransmitter acetylcholine in neuromuscular synapses through cleavage of soluble N-ethylmaleimide-sensitive fusion (NSF) attachment protein receptor (SNARE) proteins, which promote fusion of synaptic vesicles to the plasma membrane. We designed and tested a BoNT-derived targeted secretion inhibitor (TSI) targeting pituitary somatotroph cells to suppress growth hormone (GH) secretion and treat acromegaly. This recombinant protein, called SXN101742, contains a modified GH-releasing hormone (GHRH) domain and the endopeptidase domain of botulinum toxin serotype D (GHRH-LHN/D, where HN/D indicates endopeptidase and translocation domain type D). In vitro, SXN101742 targeted the GHRH receptor and depleted a SNARE protein involved in GH exocytosis, vesicle-associated membrane protein 2 (VAMP2). In vivo, administering SXN101742 to growing rats produced a dose-dependent inhibition of GH synthesis, storage, and secretion. Consequently, hepatic IGF1 production and resultant circulating IGF1 levels were reduced. Accordingly, body weight, body length, organ weight, and bone mass acquisition were all decreased, reflecting the biological impact of SXN101742 on the GH/IGF1 axis. An inactivating 2–amino acid substitution within the zinc coordination site of the endopeptidase domain completely abolished SXN101742 inhibitory actions on GH and IGF1. Thus, genetically reengineered BoNTs can be targeted to nonneural cells to selectively inhibit hormone secretion, representing a new approach to treating hormonal excess.
doi:10.1172/JCI63232
PMCID: PMC3428092  PMID: 22850878
18.  Pluripotent Stem Cell–Based Cancer Therapy: Promise and Challenges 
Science Translational Medicine  2012;4(127):127ps9.
The development of induced pluripotent stem cell (iPSC) technology has generated enthusiasm about the therapeutic potential of these cells for treating a variety of diseases. However, the evidence that they actually will be clinically useful is limited. Here, we discuss the potential therapeutic applications of iPSCs for treating cancer and other diseases and highlight the current barriers restricting their use.
doi:10.1126/scitranslmed.3003920
PMCID: PMC3397797  PMID: 22461639
19.  Rebooting the Immune System with High-Dose Cyclophosphamide for Treatment of Refractory Myasthenia Gravis 
A small but important proportion of patients with myasthenia gravis (MG) are refractory to conventional immunotherapy. We have treated 12 such patients by “rebooting” the immune system with high-dose cyclophosphamide (Hi Cy, 200 mg/kg), which largely eliminates the mature immune system, while leaving hematopoietic precursors intact. The objective of this report is to describe the clinical and immunologic results of Hi Cy treatment of refractory MG. We have followed 12 patients clinically for 1–9 years, and have analyzed their humoral and cellular immunologic parameters. Hi Cy is safe and effective. All but one of the patients experienced dramatic clinical improvement for variable periods from 5 months to 7.5 years, lasting for more than 1 year in seven of the patients. Two patients are still in treatment-free remission at 5.5 and 7.5 years, and five have achieved responsiveness to immunosuppressive agents that were previously ineffective. Hi Cy typically reduced, but did not completely eliminate, antibodies to the autoantigen AChR or to tetanus or diphtheria toxin; re-immunization with tetanus or diphtheria toxoid increased the antibody levels. Despite prior thymectomy, T cell receptor excision circles, generally considered to reflect thymic emigrant T cells, were produced by all patients. Hi Cy treatment results in effective, but often not permanent, remission in most refractory myasthenic patients, suggesting that the immune system is in fact “rebooted,” but not “reformatted.” We therefore recommend that treatment of refractory MG with Hi Cy be followed with maintenance immunotherapy.
doi:10.1196/annals.1405.033
PMCID: PMC3390145  PMID: 18567882
myasthenia gravis; refractory MG; high-dose cyclophosphamide; Hi Cy; rebooting the immune system; TRECs; autoimmunity; immunotherapy
20.  High-dose Cyclophosphamide and Rituximab without Stem Cell Transplantation: a Feasibility Study for Low Grade B cell, Transformed and Mantle Cell Lymphomas 
Leukemia & Lymphoma  2011;52(11):2076-2081.
Relapse after autologous stem cell transplantation for low-grade B-cell lymphoma is common secondary to ineffective conditioning and/or tumor autograft contamination. We investigated high-dose cyclophosphamide and rituximab without stem cell rescue as first-line or salvage-therapy in lymphomas. After establishing safety, accrual was increased to evaluate event-free survival (EFS). 81 adults received rituximab [375mg/mm days 1, 4, 8, 11, 45, 52], cyclophosphamide [50mg/kg days 15-18] and pegfilgrastim (day 20). Forty-two patients had low-grade B-cell lymphoma [grade I/II follicular (69%), transformed lymphoma (17%), other (15%)]: 45% were treated without measurable disease. Thirty-nine patients had mantle cell lymphoma: 82% were treated without measurable disease. All achieved hematopoietic recovery; 46% required brief hospitalizations. The 5 year EFS and overall survival (OS) for low-grade B-cell and transformed patients was 40% and 72%, respectively. The 5 year EFS and OS for the MCL patients was 39% and 62%, respectively. This low-toxicity therapeutic approach obviates the need for stem cell products and establishes a platform for future therapies.
doi:10.3109/10428194.2011.594191
PMCID: PMC3390263  PMID: 21756035
Cyclophosphamide; NHL; Mantle Cell Lymphoma
21.  Tim-3 Negatively Regulates Cytotoxicity in Exhausted CD8+ T Cells in HIV Infection 
PLoS ONE  2012;7(7):e40146.
Cytotoxic CD8+ T cells (CTLs) contain virus infections through the release of granules containing both perforin and granzymes. T cell ‘exhaustion’ is a hallmark of chronic persistent viral infections including HIV. The inhibitory regulatory molecule, T cell Immunoglobulin and Mucin domain containing 3 (Tim-3) is induced on HIV-specific T cells in chronic progressive infection. These Tim-3 expressing T cells are dysfunctional in terms of their capacities to proliferate or to produce cytokines. In this study, we evaluated the effect of Tim-3 expression on the cytotoxic capabilities of CD8+ T cells in the context of HIV infection. We investigated the cytotoxic capacity of Tim-3 expressing T cells by examining 1) the ability of Tim-3+ CD8+ T cells to make perforin and 2) the direct ability of Tim-3+ CD8+ T cells to kill autologous HIV infected CD4+ target cells. Surprisingly, Tim-3+ CD8+ T cells maintain higher levels of perforin, which was mainly in a granule-associated (stored) conformation, as well as express high levels of T-bet. However, these cells were also defective in their ability to degranulate. Blocking the Tim-3 signalling pathway enhanced the cytotoxic capabilities of HIV specific CD8+ T cells from chronic progressors by increasing; a) their degranulation capacity, b) their ability to release perforin, c) their ability to target activated granzyme B to HIV antigen expressing CD4+ T cells and d) their ability to suppress HIV infection of CD4+ T cells. In this latter effect, blocking the Tim-3 pathway enhances the cytotoxcity of CD8+ T cells from chronic progressors to the level very close to that of T cells from viral controllers. Thus, the Tim-3 receptor, in addition to acting as a terminator for cytokine producing and proliferative functions of CTLs, can also down-regulate the CD8+ T cell cytotoxic function through inhibition of degranulation and perforin and granzyme secretion.
doi:10.1371/journal.pone.0040146
PMCID: PMC3390352  PMID: 22792231
22.  Insulin Detemir Reduces Weight Gain as a Result of Reduced Food Intake in Patients With Type 1 Diabetes 
Diabetes Care  2011;34(7):1487-1491.
OBJECTIVE
Insulin detemir lacks the usual propensity for insulin to cause weight gain. We investigated whether this effect was a result of reduced energy intake and/or increased energy expenditure.
RESEARCH DESIGN AND METHODS
A 32-week, randomized crossover design trial was undertaken in 23 patients with type 1 diabetes. Patients on a basal-bolus regimen (with insulin aspart as the bolus insulin) were randomly assigned to insulin detemir or NPH insulin as a basal insulin for 16 weeks, followed by the other basal insulin for 16 weeks. At the end of each 16-week period, total energy expenditure, resting energy expenditure, diet-induced thermogenesis, activity energy expenditure, energy intake, weight change, glycemic control, hypoglycemic episodes, and hormones that affect satiety and fuel partitioning were measured.
RESULTS
After 16 weeks, weight change was −0.69 ± 1.85 kg with insulin detemir and +1.7 ± 2.46 kg with NPH insulin (P < 0.001). Total energy intake was significantly less with insulin detemir (2,016 ± 501 kcal/day) than with NPH insulin (2,181 ± 559 kcal/day) (P = 0.026). There was no significant difference in any measure of energy expenditure, HbA1c percentage, or number of hypoglycemic episodes. Leptin was lower and resistin was higher with insulin detemir compared with NPH insulin (P = 0.039, P = 0.047). After the meal, ghrelin and pancreatic polypeptide levels (P = 0.002, P = 0.001) were higher with insulin detemir.
CONCLUSIONS
The reduced weight gain with insulin detemir compared with NPH insulin is attributed to reduced energy intake rather than increased energy expenditure. This may be mediated by a direct or indirect effect of insulin detemir on the hormones that control satiety.
doi:10.2337/dc11-0098
PMCID: PMC3120205  PMID: 21593292
23.  Inter-assessor reliability of practice based biomechanical assessment of the foot and ankle 
Background
There is no consensus on which protocols should be used to assess foot and lower limb biomechanics in clinical practice. The reliability of many assessments has been questioned by previous research. The aim of this investigation was to (i) identify (through consensus) what biomechanical examinations are used in clinical practice and (ii) evaluate the inter-assessor reliability of some of these examinations.
Methods
Part1: Using a modified Delphi technique 12 podiatrists derived consensus on the biomechanical examinations used in clinical practice. Part 2: Eleven podiatrists assessed 6 participants using a subset of the assessment protocol derived in Part 1. Examinations were compared between assessors.
Results
Clinicians choose to estimate rather than quantitatively measure foot position and motion. Poor inter-assessor reliability was recorded for all examinations. Intra-class correlation coefficient values (ICC) for relaxed calcaneal stance position were less than 0.23 and were less than 0.14 for neutral calcaneal stance position. For the examination of ankle joint dorsiflexion, ICC values suggest moderate reliability (less than 0.61). The results of a random effects ANOVA highlight that participant (up to 5.7°), assessor (up to 5.8°) and random (up to 5.7°) error all contribute to the total error (up to 9.5° for relaxed calcaneal stance position, up to 10.7° for the examination of ankle joint dorsiflexion). Kappa Fleiss values for categorisation of first ray position and mobility were less than 0.05 and for limb length assessment less than 0.02, indicating slight agreement.
Conclusion
Static biomechanical assessment of the foot, leg and lower limb is an important protocol in clinical practice, but the key examinations used to make inferences about dynamic foot function and to determine orthotic prescription are unreliable.
doi:10.1186/1757-1146-5-14
PMCID: PMC3431260  PMID: 22716130
24.  The Non-linear Relationship between Gait Speed and Falls: The MOBILIZE Boston Study 
OBJECTIVES
Although several studies suggest that slow gait speed is a predictor of falls, it may also be a protective mechanism to prevent falls. Further, fast walking may precipitate falls. Therefore, we examined the relationship between gait speed and falls risk.
DESIGN
Longitudinal analysis of the association between gait speed and subsequent falls and analysis of gait speed decline as a predictor of future falls
SETTING
Population-based cohort study
PARTICIPANTS
763 community-dwelling elders underwent baseline assessments and were followed for falls. Of these, 600 completed an 18-month follow-up assessment to determine change in gait speed and were followed for subsequent falls.
MEASUREMENTS
Gait speed was measured during a 4-meter walk, falls data were collected from monthly post-card calendars, and covariates were collected from in-home and clinic visits.
RESULTS
There was a U-shaped relation between gait speed and falls with faster (≥1.3 m/s, incident rate ratio (IRR) = 2.12, 95% CI = 1.48 – 3.04) and slower speeds (<0.6 m/sec, IRR = 1.60, CI = 1.06 – 2.42) at highest risk compared to normal gait speeds (≥1.0 and < 1.3 m/sec). In adjusted analyses, slower gait speeds were associated with an increased risk ratio for indoor falls (for <0.6 m/sec, IRR = 2.17, CI = 1.33 – 3.55 and for ≥0.6 and <1.0 m/sec, IRR = 1.45, CI = 1.08 – 1.94). Faster gait speed was associated with an increased risk ratio for outdoor falls (IRR = 2.11, CI = 1.40 – 3.16). A gait speed decline of >0.15 m/sec/year predicted an increased risk for all falls (IRR = 1.86, CI = 1.15 – 3.01).
CONCLUSION
There is a non-linear relation between gait speed and falls with a greater risk of outdoor falls in faster walkers and greater risk of indoor falls in slow walkers.
doi:10.1111/j.1532-5415.2011.03408.x
PMCID: PMC3141220  PMID: 21649615
25.  Inhibition of Staphylococcus aureus by Lysostaphin-Expressing Lactobacillus plantarum WCFS1 in a Modified Genital Tract Secretion Medium▿† 
Applied and Environmental Microbiology  2011;77(24):8500-8508.
Lactobacillus species are a predominant member of the vaginal microflora and are critical in maintaining an acidic vaginal environment thought to contribute to the prevention of a number of urogenital diseases. However, during menstruation the pH of the vaginal environment increases to neutrality, a pH conducive for Staphylococcus aureus proliferation and the production of toxic shock syndrome toxin 1 (TSST-1) in susceptible women. In order to generate Lactobacillus species capable of expressing lysostaphin (an endopeptidase that cleaves the cell wall of S. aureus) in a modified genital tract secretion medium (mGTS) under neutral-pH conditions, six prominent proteins from Lactobacillus plantarum WCFS1 spent medium were identified by mass spectrometry. Sequences for promoters, signal peptides, and mature lysostaphin were used to construct plasmids that were subsequently transformed into L. plantarum WCFS1. The promoter and signal sequences of Lp_3014 (putatively identified as a transglycosylase) or the promoter sequence of Lp_0789 (putatively identified as glyceraldehyde 3-phosphate dehydrogenase) with the signal sequence of Lp_3014 exhibited lysostaphin activity on buffered medium containing heat-killed S. aureus. The cassettes were integrated into the chromosome of L. plantarum WCFS1, but only the cassette containing the promoter and signal sequence from Lp_3014 had integrated into the appropriate site. Coculture assays using buffered mGTS showed that lysostaphin expressed from L. plantarum WCFS1 reduced the growth of TSST-1-producing strains of S. aureus under neutral-pH conditions. This study provides the basis for determining whether lysostaphin-producing Lactobacillus strains could potentially be used as a means to inhibit the growth of S. aureus during menstruation.
doi:10.1128/AEM.06755-11
PMCID: PMC3233112  PMID: 21984245

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