Abnormal depth perception from motion parallax in amblyopic observers

AbstractMany similarities exist between the perception of depth from binocular stereopsis and that from motion parallax. Moreover, Rogers (1984, cited in, Howard, I. P., & Rogers, B. J. (1995). Binocular vision and stereopsis. Oxford Claridon, New York.) suggests a relationship between an observer’s ability to use disparity information and motion parallax information in a depth perception task. To more closely investigate this relationship, depth perception was studied in normal observers and amblyopic observers with poor stereo vision. As expected, amblyopic observers performed much worse than normal observers on depth discriminations requiring use of binocular disparity. However, amblyopic observers also performed much worse than normal observers on depth discriminations based on motion parallax. This result provides supporting evidence for a psychoanatomical link between the perception of depth from motion and the perception of depth from binocular disparity

Meeting the challenges of recruitment to multicentre, community-based, lifestyle-change trials : a case study of the BeWEL trial

Peer reviewedPublisher PD

The use of repeated blood pressure measures for cardiovascular risk prediction: a comparison of statistical models in the ARIC study.

Many prediction models have been developed for the risk assessment and the prevention of cardiovascular disease in primary care. Recent efforts have focused on improving the accuracy of these prediction models by adding novel biomarkers to a common set of baseline risk predictors. Few have considered incorporating repeated measures of the common risk predictors. Through application to the Atherosclerosis Risk in Communities study and simulations, we compare models that use simple summary measures of the repeat information on systolic blood pressure, such as (i) baseline only; (ii) last observation carried forward; and (iii) cumulative mean, against more complex methods that model the repeat information using (iv) ordinary regression calibration; (v) risk-set regression calibration; and (vi) joint longitudinal and survival models. In comparison with the baseline-only model, we observed modest improvements in discrimination and calibration using the cumulative mean of systolic blood pressure, but little further improvement from any of the complex methods. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.J.K.B. was supported by the Medical Research Council grant numbers G0902100 and MR/K014811/1. This work was funded by the UK Medical Research Council (G0800270), British Heart Foundation (SP/09/002), UK National Institute for Health Research Cambridge Biomedical Research Centre, European Research Council (268834) and European Commission Framework Programme 7 (HEALTH-F2-2012-279233). The ARIC study is carried out as a collaborative study supported by the National Heart, Lung, and Blood Institute contracts (HHSN268201100005C, HHSN268201100006C, HHSN268201100007C, HHSN268201100008C, HHSN268201100009C, HHSN268201100010C, HHSN268201100011C and HHSN268201100012C).This is the final version of the article. It first appeared from Wiley via https://doi.org/10.1002/sim.714

A review of published analyses of case-cohort studies and recommendations for future reporting.

The case-cohort study design combines the advantages of a cohort study with the efficiency of a nested case-control study. However, unlike more standard observational study designs, there are currently no guidelines for reporting results from case-cohort studies. Our aim was to review recent practice in reporting these studies, and develop recommendations for the future. By searching papers published in 24 major medical and epidemiological journals between January 2010 and March 2013 using PubMed, Scopus and Web of Knowledge, we identified 32 papers reporting case-cohort studies. The median subcohort sampling fraction was 4.1% (interquartile range 3.7% to 9.1%). The papers varied in their approaches to describing the numbers of individuals in the original cohort and the subcohort, presenting descriptive data, and in the level of detail provided about the statistical methods used, so it was not always possible to be sure that appropriate analyses had been conducted. Based on the findings of our review, we make recommendations about reporting of the study design, subcohort definition, numbers of participants, descriptive information and statistical methods, which could be used alongside existing STROBE guidelines for reporting observational studies.SJS was supported by the Medical Research Council www.mrc.ac.uk [Unit Programme number MC_UU_12015/1]. IRW was supported by the Medical Research Council www.mrc.ac.uk [Unit Programme number U105260558]. MP, SGT and AMW were supported by the British Heart Foundation www.bhf.org.uk [grant number CH/12/2/29428].This is the final published version distributed under a Creative Commons Attribution License 2.0, which can also be viewed on the publisher's website at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.010117

Contribution of G Protein Activation to Fluoride Stimulation of Phosphoinositide Hydrolysis in Human Neuroblastoma Cells

To examine the possibility that NaF enhances phosphoinositide-specific phospholipase C (PIC) activity in neural tissues by a mechanism independent of a guanine nucleotide binding protein (G p ), we have evaluated the contribution of G p activation to NaF-stimulated phosphoinositide hydrolysis in human SK-N-SH neuroblastoma cells. Addition of NaF to intact cells resulted in an increase in the release of inositol phosphates (450% of control values; EC 50 of ∼ 8 m M ). Inclusion of U-73122, an aminosteroid inhibitor of guanine nucleotide-regulated PIC activity in these cells, resulted in a dose-dependent inhibition of NaF-stimulated inositol lipid hydrolysis (IC 50 of ∼ 3.5 Μ M ). When added to digitonin-permeabilized cells, NaF or guanosine-5′- O -thiotriphosphate (GTPΓS) resulted in a three- and sevenfold enhancement, respectively, of inositol phosphate release. In the combined presence of optimal concentrations of NaF and GTPΓS, inositol phosphate release was less than additive, indicative of a common site of action. Inclusion of 2–5 m M concentrations of guanosine-5′- O -(2-thiodiphosphate) (GDPΒS) fully blocked phosphoinositide hydrolysis elicited by GTPΓS, whereas that induced by NaF was partially inhibited (65%). However, preincubation of the cells with GDPΒS resulted in a greater reduction in the ability of NaF to stimulate inositol phosphate release (87% inhibition). Both GTPΓS and NaF-stimulated inositol phosphate release were inhibited by inclusion of 10 Μ M U-73122 (54–71%). The presence of either NaF or GTPΓS also resulted in a marked lowering of the Ca 2+ requirement for activation of PIC in permeabilized cells. These results indicate that in SK-N-SH cells, little evidence exists for direct stimulation of PIC by NaF and that the majority of inositol phosphate release that occurs in the presence of NaF can be attributed to activation of G p .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65259/1/j.1471-4159.1993.tb13406.x.pd

Examination of Fluconazole-Induced Alopecia in an Animal Model and Human Cohort.

Fluconazole-induced alopecia is a significant problem for patients receiving long-term therapy. We evaluated the hair cycle changes of fluconazole in a rat model and investigated potential molecular mechanisms. Plasma and tissue levels of retinoic acid were not found to be causal. Human patients with alopecia attributed to fluconazole also underwent detailed assessment and in both our murine model and human cohort fluconazole induced telogen effluvium. Future work further examining the mechanism of fluconazole-induced alopecia should be undertaken

Design and methods for a randomized clinical trial of a diabetes self-management intervention for low-Income Latinos: Latinos en Control

<p>Abstract</p> <p>Background</p> <p>US Latinos have greater prevalence of type 2 diabetes (diabetes), uncontrolled diabetes and diabetes co-morbidities compared to non-Latino Whites. They also have lower literacy levels and are more likely to live in poverty. Interventions are needed to improve diabetes control among low-income Latinos.</p> <p>Methods and design</p> <p>This randomized clinical trial tested the efficacy of a culturally- and literacy-tailored diabetes self-management intervention (<it>Latinos en Control</it>) on glycemic control among low-income Latinos with diabetes, compared to usual care (control). Participants were recruited from five community health centers (CHCs) in Massachusetts. The theory-based intervention included an intensive phase of 12 weekly sessions and a follow-up maintenance phase of 8 monthly sessions. Assessments occurred at baseline, and at 4 and 12 months. The primary outcome was glycosylated hemoglobin (HbA1c). Secondary outcomes were self-management behaviors, weight, lipids and blood pressure. Additional outcomes included diabetes knowledge, self-efficacy, depression and quality of life. The study was designed for recruitment of 250 participants (estimated 20% dropout rate) to provide 90% power for detecting a 7% or greater change in HbA1c between the intervention and control groups. This is a difference in change of HbA1c of 0.5 to 0.6%.</p> <p>Discussion</p> <p>Low-income Latinos bear a great burden of uncontrolled diabetes and are an understudied population. Theory-based interventions that are tailored to the needs of this high-risk population have potential for improving diabetes self-management and reduce health disparities. This article describes the design and methods of a theory driven intervention aimed at addressing this need.</p> <p>Trial registration</p> <p><url>http://www.clinicaltrials.gov</url> # NCT00848315</p