The interpretation of particle size, shape, and carbon flux of marine particle images is strongly affected by the choice of particle detection algorithm

In situ imaging of particles in the ocean are rapidly establishing themselves as powerful tools to investigate the ocean carbon cycle, including the role of sinking particles for carbon sequestration via the biological carbon pump. A big challenge when analysing particles in camera images is determining the size of the particle, which is required to calculate carbon content, sinking velocity and flux. A key image processing decision is the algorithm used to decide which part of the image forms the particle and which is the background. However, this critical analysis step is often unmentioned and its effect rarely explored. Here we show that final flux estimates can easily vary by an order of magnitude when selecting different algorithms for a single dataset. We applied a range of static threshold values and 11 different algorithms (seven threshold and four edge detection algorithms) to particle profiles collected by the LISST-Holo system in two contrasting environments. Our results demonstrate that the particle detection method does not only affect estimated particle size but also particle shape. Uncertainties are likely exacerbated when different particle detection methods are mixed, e.g., when datasets from different studies or devices are merged. We conclude that there is a clear need for more transparent method descriptions and justification for particle detection algorithms, as well as for a calibration standard that allows intercomparison between different devices

Systemic reduction in glutathione levels occurs in patients with primary open-angle glaucoma

PURPOSE. To assess the level of plasma glutathione in patients with untreated primary open-angle glaucoma. METHODS. Twenty-one patients with newly diagnosed primary open-angle glaucoma and 34 age- and gender-matched control subjects were subjected to a blood analysis to detect the level of circulating glutathione in its reduced and oxidized forms. The effect of age, gender, and systemic blood pressure on circulating glutathione levels was also analyzed. RESULTS. Age had a negative effect on the level of both reduced and total glutathione (P = 0.002, r = -0.52 and P = 0.002, r = -0.52, respectively) in control subjects but not in patients with glaucoma (P > 0.05, r = 0.27, and P > 0.05, r = 0.22, respectively). In the control group, men demonstrated higher levels of both reduced and total glutathione than did women (P = 0.024 and P = 0.032, respectively). After correction for age and gender influences on blood glutathione levels, patients with glaucoma exhibited significantly lower levels of reduced and total glutathione than did control subjects (P = 0.010, F = 7.24 and P = 0.006, F = 8.38, respectively). No differences between study groups were observed in either oxidized glutathione levels or redox index (P > 0.05, F = 0.50; and P > 0.05, F = 0.30, respectively). CONCLUSIONS. Patients with glaucoma exhibit low levels of circulating glutathione, suggesting a general compromise of the antioxidative defense. Copyright © Association for Research in Vision and Ophthalmology

Long-term fluctuation in short-wavelength automated perimetry in glaucoma suspects and glaucoma patients

PURPOSE. To determine the magnitude of the homogenous, LF(Ho), and the heterogeneous, LF(He), components of the long-term fluctuation (LF) in glaucoma suspects and in stable primary open angle glaucoma (POAG) patients undergoing short-wavelength automated perimetry (SWAP) and to compare the magnitude of the SWAP LF components with those elicited by standard white-on-white (W-W) perimetry. METHODS. The sample comprised 33 glaucoma suspects and 17 patients with early-to-moderate stable POAG who underwent W-W perimetry and SWAP at each of six visits over a mean period of 12.75 months (SD, 2.29). The LF(Ho), LF(He), and error components of the long-term fluctuation were determined between the third and seventh visual field examinations. The intervening visual field examinations and the optic nerve head parameters, derived both by stereo observation and by the Heidelberg Retinal Tomograph, were used to confirm stability over the follow-up period. RESULTS. The LF(Ho) and LF(He) components were larger in the POAG patients than in the glaucoma suspects for both W-W perimetry and SWAP; the magnitude was independent of the depth of defect and of the short-term fluctuation. All three components of long-term fluctuation were greater for SWAP than for W-W perimetry, both in the glaucoma suspects and in the POAG patients. CONCLUSIONS. SWAP exhibits greater long-term fluctuation than white-on-white perimetry. The usefulness of SWAP will be limited if the extent of this variability is not overcome in future statistical procedures developed to detect progressive visual field loss

Comparison of fracture rates between indigenous and non-indigenous populations: a systematic review protocol

INTRODUCTION: Over recent years, there has been concerted effort to \u27close the gap\u27 in the disproportionately reduced life expectancy and increased morbidity experienced by indigenous compared to non-indigenous persons. Specific to musculoskeletal health, some data suggest that indigenous peoples have a higher risk of sustaining a fracture compared to non-indigenous peoples. This creates an imperative to identify factors that could explain differences in fracture rates. This protocol presents our aim to conduct a systematic review, first, to determine whether differences in fracture rates exist for indigenous versus non-indigenous persons and, second, to identify any risk factors that might explain these differences. METHODS AND ANALYSIS: We will conduct a systematic search of PubMed, OVID, MEDLINE, CINAHL and EMBASE to identify articles that compare all-cause fracture rates at any skeletal site between indigenous and non-indigenous persons of any age. Eligibility of studies will be determined by 2 independent reviewers. Studies will be assessed for methodological quality using a previously published process. We will conduct a meta-analysis and use established statistical methods to identify and control for heterogeneity where appropriate. Should heterogeneity prevents numerical syntheses, we will undertake a best-evidence analysis to determine the level of evidence for differences in fracture between indigenous and non-indigenous persons. ETHICS AND DISSEMINATION: This systematic review will use published data; thus, ethical permissions are not required. In addition to peer-reviewed publication, findings will be presented at (inter)national conferences, disseminated electronically and in print, and will be made available to key country-specific decision-makers with authority for indigenous health

Fractures in indigenous compared to non-indigenous populations: a systematic review of rates and aetiology

BackgroundCompared to non-indigenous populations, indigenous populations experience disproportionately greater morbidity, and a reduced life expectancy; however, conflicting data exist regarding whether a higher risk of fracture is experienced by either population. We systematically evaluate evidence for whether differences in fracture rates at any skeletal site exist between indigenous and non-indigenous populations of any age, and to identify potential risk factors that might explain these differences.MethodsOn 31 August 2016 we conducted a comprehensive computer-aided search of peer-reviewed literature without date limits. We searched PubMed, OVID, MEDLINE, CINAHL, EMBASE, and reference lists of relevant publications. The protocol for this systematic review is registered in PROSPERO, the International Prospective Register of systematic reviews (CRD42016043215). Using the World Health Organization reference population as standard, hip fracture incidence rates were re-standardized for comparability between countries.ResultsOur search yielded 3227 articles; 283 potentially eligible articles were cross-referenced against predetermined criteria, leaving 27 articles for final inclusion. Differences in hip fracture rates appeared as continent-specific, with lower rates observed for indigenous persons in all countries except for Canada and Australia where the opposite was observed. Indigenous persons consistently had higher rates of trauma-related fractures; the highest were observed in Australia where craniofacial fracture rates were 22-times greater for indigenous compared to non-indigenous women. After adjustment for socio-demographic and clinical risk factors, approximately a three-fold greater risk of osteoporotic fracture and five-fold greater risk of craniofacial fractures was observed for indigenous compared to non-indigenous persons; diabetes, substance abuse, comorbidity, lower income, locality, and fracture history were independently associated with an increased risk of fracture.ConclusionsThe observed paucity of data and suggestion of continent-specific differences indicate an urgent need for further research regarding indigenous status and fracture epidemiology and aetiology. Our findings also have implications for communities, governments and healthcare professionals to enhance the prevention of trauma-related fractures in indigenous persons, and an increased focus on modifiable lifestyle behaviours to prevent osteoporotic fractures in all populations

Short-term stability in refractive status despite large fluctuations in glucose levels in diabetes mellitus type 1 and 2

Purpose: This work investigates how short-term changes in blood glucose concentration affect the refractive components of the diabetic eye in patients with long-term Type 1 and Type 2 diabetes. Methods: Blood glucose concentration, refractive error components (mean spherical equivalent MSE, J0, J45), central corneal thickness (CCT), anterior chamber depth (ACD), crystalline lens thickness (LT), axial length (AL) and ocular aberrations were monitored at two-hourly intervals over a 12-hour period in: 20 T1DM patients (mean age ± SD) 38±14 years, baseline HbA1c 8.6±1.9%; 21 T2DM patients (mean age ± SD) 56±11 years, HbA1c 7.5±1.8%; and in 20 control subjects (mean age ± SD) 49±23 years, HbA1c 5.5±0.5%. The refractive and biometric results were compared with the corresponding changes in blood glucose concentration. Results: Blood glucose concentration at different times was found to vary significantly within (p0.05). Minor changes of marginal statistical or optical significance were observed in some biometric parameters. Similarly there were some marginally significant differences between the baseline biometric parameters of well-controlled and poorly-controlled diabetic subjects. Conclusion: This work suggests that normal, short-term fluctuations (of up to about 6 mM/l on a timescale of a few hours) in the blood glucose levels of diabetics are not usually associated with acute changes in refractive error or ocular wavefront aberrations. It is therefore possible that factors other than refractive error fluctuations are sometimes responsible for the transient visual problems often reported by diabetic patients

Inherited variation in immune genes and pathways and glioblastoma risk

To determine whether inherited variations in immune function single-nucleotide polymorphisms (SNPs), genes or pathways affect glioblastoma risk, we analyzed data from recent genome-wide association studies in conjunction with predefined immune function genes and pathways. Gene and pathway analyses were conducted on two independent data sets using 6629 SNPs in 911 genes on 17 immune pathways from 525 glioblastoma cases and 602 controls from the University of California, San Francisco (UCSF) and a subset of 6029 SNPs in 893 genes from 531 cases and 1782 controls from MD Anderson (MDA). To further assess consistency of SNP-level associations, we also compared data from the UK (266 cases and 2482 controls) and the Mayo Clinic (114 cases and 111 controls). Although three correlated epidermal growth factor receptor (EGFR) SNPs were consistently associated with glioblastoma in all four data sets (Mantel–Haenzel P values = 1 × 10−5 to 4 × 10−3), independent replication is required as genome-wide significance was not attained. In gene-level analyses, eight immune function genes were significantly (minP < 0.05) associated with glioblastoma; the IL-2RA (CD25) cytokine gene had the smallest minP values in both UCSF (minP = 0.01) and MDA (minP = 0.001) data sets. The IL-2RA receptor is found on the surface of regulatory T cells potentially contributing to immunosuppression characteristic of the glioblastoma microenvironment. In pathway correlation analyses, cytokine signaling and adhesion–extravasation–migration pathways showed similar associations with glioblastoma risk in both MDA and UCSF data sets. Our findings represent the first systematic description of immune genes and pathways that characterize glioblastoma risk

Recurrent Coding Sequence Variation Explains only A Small Fraction of the Genetic Architecture of Colorectal Cancer

Whilst common genetic variation in many non-coding genomic regulatory regions are known to impart risk of colorectal cancer (CRC), much of the heritability of CRC remains unexplained. To examine the role of recurrent coding sequence variation in CRC aetiology, we genotyped 12,638 CRCs cases and 29,045 controls from six European populations. Single-variant analysis identified a coding variant (rs3184504) in SH2B3 (12q24) associated with CRC risk (OR = 1.08, P = 3.9 × 10-7), and novel damaging coding variants in 3 genes previously tagged by GWAS efforts; rs16888728 (8q24) in UTP23 (OR = 1.15, P = 1.4 × 10-7); rs6580742 and rs12303082 (12q13) in FAM186A (OR = 1.11, P = 1.2 × 10-

Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer.

To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC

Non‐invasive vascular impedance measures demonstrate ocular vasoconstriction during isometric exercise

AIMS: The calculation of impedance for a vascular network is a common method used in circulation studies. Impedance indices (the ratios of the harmonics of pressure to the harmonics of flow) provide the investigator with a measure of the opposition to blood flow in a pulsatile system and are a proven indicator for vasculopathy. Previous studies investigating the eye's opposition to blood flow have concentrated on simple measures of resistance (the ratio of mean pressure difference to mean flow) which are more appropriate to a steady state or non‐pulsatile system. The purpose of this study is to demonstrate a new, non‐invasive, method to determine the vascular impedance of the eye during the known physiologic stress of sustained isometric exercise. METHODS: Waveforms of ocular blood flow and carotid arterial blood pressure were measured non‐invasively. Ocular blood flow waveforms were calculated using the Langham‐Silver method by measuring the small fluctuations in intraocular pressure intraocular pressure over time with a high fidelity pneumatonometer. Carotid arterial blood pressure waveforms were determined using a SphygmoCor electronic tonometer held over the common carotid artery of the neck. Both waveforms were recorded simultaneously in normal volunteers under two conditions: (1) a baseline resting state and (2) during sustained isometric exercise. The components of the two waveforms (the harmonics) were calculated using a Fast Fourier transform and expressed as a ratio in order to determine a set of impedance values for each condition. The first four impedance values were calculated. RESULTS: 12 volunteers (six male: six female) with a mean age of 27 years (range 22–32 years) were recruited to the study. In comparison to baseline resting conditions, mean carotid blood pressure and heart rate both increased significantly during exercise: baseline mean carotid blood pressure, 82.6±8.2 mm Hg vs exercise mean carotid blood pressure, 93.8±12.8 mm Hg (p<0.001); baseline pulse rate, 64.6±9.1 BP(m) vs exercise pulse rate, 71.8±9.7 BP(m) (p<0.001). Compared to resting conditions, the first and third impedance values demonstrated significant change during exercise: the first impedance value rose (83.9±25.6 mm Hg‐s/μl to 117.1 ± 40.9 mm Hg‐s/μl, p = 0.01) and the third impedance value fell (487.9 ± 294.7 mm Hg‐s/μl to 248.3±206.8 mm Hg‐s/μl, p = 0.01). CONCLUSIONS: The present study demonstrates, for the first time, a practical non‐invasive method of calculating an index of impedance moduli for the pulsatile quotient of blood flow to the eye. Furthermore, during controlled isometric exercise, the impedance moduli displayed changes consistent with that known for a vascular system during vasoconstriction. The calculation of impedance moduli for the eye therefore shows promise for future investigations into ocular conditions where vascular obstruction is an aetiological factor