Revealing low-dose radiation damage using single-crystal spectroscopy

Data on the rapid reduction of haem proteins in the X-ray beam at synchrotron sources are presented. The use of single-crystal spectroscopy to detect these changes and their implication for diffraction data collection from oxidized species is also discussed

A new on-axis multimode spectrometer for the macromolecular crystallography beamlines of the Swiss Light Source

Complementary techniques greatly aid the interpretation of macromolecule structures to yield functional information, and can also help to track radiation-induced changes. A new on-axis spectrometer being integrated into the macromolecular crystallography beamlines of the Swiss Light Source is presented

The HARE chip for efficient time-resolved serial synchrotron crystallography

Serial synchrotron crystallography (SSX) is an emerging technique for static and time-resolved protein structure determination. Using specifically patterned silicon chips for sample delivery, the `hit-and-return' (HARE) protocol allows for efficient time-resolved data collection. The specific pattern of the crystal wells in the HARE chip provides direct access to many discrete time points. HARE chips allow for optical excitation as well as on-chip mixing for reaction initiation, making a large number of protein systems amenable to time-resolved studies. Loading of protein microcrystals onto the HARE chip is streamlined by a novel vacuum loading platform that allows fine-tuning of suction strength while maintaining a humid environment to prevent crystal dehydration. To enable the widespread use of time-resolved serial synchrotron crystallography (TR-SSX), detailed technical descriptions of a set of accessories that facilitate TR-SSX workflows are provided

Stem cell niche organization in the Drosophila ovary requires the ECM component Perlecan.

Stem cells reside in specialized microenvironments or niches that balance stem cell proliferation and differentiation.1,2 The extracellular matrix (ECM) is an essential component of most niches, because it controls niche homeostasis, provides physical support, and conveys extracellular signals.3-11 Basement membranes (BMs) are thin ECM sheets that are constituted mainly by Laminins, Perlecan, Collagen IV, and Entactin/Nidogen and surround epithelia and other tissues.12 Perlecans are secreted proteoglycans that interact with ECM proteins, ligands, receptors, and growth factors such as FGF, PDGF, VEGF, Hedgehog, and Wingless.13-18 Thus, Perlecans have structural and signaling functions through the binding, storage, or sequestering of specific ligands. We have used the Drosophila ovary to assess the importance of Perlecan in the functioning of a stem cell niche. Ovarioles in the adult ovary are enveloped by an ECM sheath and possess a tapered structure at their anterior apex termed the germarium. The anterior tip of the germarium hosts the germline niche, where two to four germline stem cells (GSCs) reside together with a few somatic cells: terminal filament cells (TFCs), cap cells (CpCs), and escort cells (ECs).19 We report that niche architecture in the developing gonad requires trol, that niche cells secrete an isoform-specific Perlecan-rich interstitial matrix, and that DE-cadherin-dependent stem cell-niche adhesion necessitates trol. Hence, we provide evidence to support a structural role for Perlecan in germline niche establishment during larval stages and in the maintenance of a normal pool of stem cells in the adult niche

Evaluation of Serum 1,5 Anhydroglucitol Levels as a Clinical Test to Differentiate Subtypes of Diabetes

OBJECTIVE: Assignment of the correct molecular diagnosis in diabetes is necessary for informed decisions regarding treatment and prognosis. Better clinical markers would facilitate discrimination and prioritization for genetic testing between diabetes subtypes. Serum 1,5 anhydroglucitol (1,5AG) levels were reported to differentiate maturity-onset diabetes of the young due to HNF1A mutations (HNF1A-MODY) from type 2 diabetes, but this requires further validation. We evaluated serum 1,5AG in a range of diabetes subtypes as an adjunct for defining diabetes etiology. RESEARCH DESIGN AND METHODS: 1,5AG was measured in U.K. subjects with: HNF1A-MODY (n = 23), MODY due to glucokinase mutations (GCK-MODY, n = 23), type 1 diabetes (n = 29), latent autoimmune diabetes in adults (LADA, n = 42), and type 2 diabetes (n = 206). Receiver operating characteristic curve analysis was performed to assess discriminative accuracy of 1,5AG for diabetes etiology. RESULTS: Mean (SD range) 1,5AG levels were: GCK-MODY 13.06 microg/ml (5.74-29.74), HNF1A-MODY 4.23 microg/ml (2.12-8.44), type 1 diabetes 3.09 microg/ml (1.45-6.57), LADA 3.46 microg/ml (1.42-8.45), and type 2 diabetes 5.43 (2.12-13.23). Levels in GCK-MODY were higher than in other groups (P < 10(-4) vs. each group). HNF1A-MODY subjects showed no difference in unadjusted 1,5AG levels from type 2 diabetes, type 1 diabetes, and LADA. Adjusting for A1C revealed a difference between HNF1A-MODY and type 2 diabetes (P = 0.001). The discriminative accuracy of unadjusted 1,5AG levels was 0.79 for GCK-MODY versus type 2 diabetes and 0.86 for GCK-MODY versus HNF1A-MODY but was only 0.60 for HNF1A-MODY versus type 2 diabetes. CONCLUSIONS: In our dataset, serum 1,5AG performed well in discriminating GCK-MODY from other diabetes subtypes, particularly HNF1A-MODY. Measurement of 1,5AG levels could inform decisions regarding MODY diagnostic testing

A Rapid Electronic Cognitive Assessment Measure for Multiple Sclerosis: Validation of Cognitive Reaction, an Electronic Version of the Symbol Digit Modalities Test

Background: incorporating cognitive testing into routine clinical practice is a challenge in multiple sclerosis (MS), given the wide spectrum of both cognitive and physical impairments people can have and the time that testing requires. Shortened paper and verbal assessments predominate but still are not used routinely. Computer-based tests are becoming more widespread; however, changes in how a paper test is implemented can impact what exactly is being assessed in an individual. The Symbol Digit Modalities Test (SDMT) is one validated test that forms part of the cognitive batteries used in MS and has some computer-based versions. We developed a tablet-based SDMT variant that has the potential to be ultimately deployed to patients' own devices.Objective: this paper aims to develop, validate, and deploy a computer-based SDMT variant, the Cognition Reaction (CoRe) test, that can reliably replicate the characteristics of the paper-based SDMT.Methods: we carried out analysis using Pearson and intraclass correlations, as well as a Bland-Altman comparison, to examine consistency between the SDMT and CoRe tests and for test-retest reliability. The SDMT and CoRe tests were evaluated for sensitivity to disability levels and age. A novel metric in CoRe was found: question answering velocity could be calculated. This was evaluated in relation to disability levels and age for people with MS and compared with a group of healthy control volunteers.Results: SDMT and CoRe test scores were highly correlated and consistent with 1-month retest values. Lower scores were seen in patients with higher age and some effect was seen with increasing disability. There was no learning effect evident. Question answering velocity demonstrated a small increase in speed over the 90-second duration of the test in people with MS and healthy controls.Conclusions: this study validates a computer-based alternative to the SDMT that can be used in clinics and beyond. It enables accurate recording of elements of cognition relevant in MS but offers additional metrics that may offer further value to clinicians and people with MS

Mental health of people with multiple sclerosis during the COVID-19 outbreak: A prospective cohort and cross-sectional case–control study of the UK MS Register

Background: People with MS (pwMS) have had higher rates of anxiety and depression than the general population before the COVID-19 pandemic, placing them at higher risk of experiencing poor psychological wellbeing during the pandemic.Objective: To assess mental health and its social/lifestyle determinants in pwMS during the first wave of the outbreak in the UK.Methods: This is a community-based, prospective longitudinal cohort and cross-sectional case-control online questionnaire study. It includes 2,010 pwMS from the UK MS Register and 380 people without MS.Results: The Hospital Anxiety and Depression Scale scores of pwMS for anxiety and depression during the outbreak did not change from the previous year. PwMS were more likely to have anxiety (using General Anxiety Disorder-7) and/or depression (using Patient Health Questionnaire-9) than controls during the outbreak (OR:2.14[95%CI:1.58-2.91]). PwMS felt lonelier (OR:1.37[95%CI:1.04-1.80]), reported worse social support (OR:1.90[95%CI:1.18-3.07]) and reported worsened exercise habits (OR:1.65[95%CI:1.18-2.32]) during the outbreak than controls.Conclusion: Early in the pandemic, pwMS remained at higher risk of experiencing anxiety and depression than the general population. It is important that multidisciplinary teams improve their support for the wellbeing of pwMS, who are vulnerable to the negative effects of the pandemic on their lifestyle and social support

Calibration of overtopping roughness factors for concrete armor units in non-breaking conditions using the CLASH database

The roughness factor (γf) is a parameter used in overtopping estimators to account for the effects of armor unit geometry, the number of layers in the armor and other structural characteristics. Different values of γf for the same armors are given in the literature; however, in this study, the value of γf was calibrated for each overtopping estimator using the best available overtopping data. A methodology based on a bootstrapping technique is proposed to statistically characterize the roughness factors which best fit each formula. For each selected armor unit and overtopping formula, three percentiles (10%, 50% and 90%) of γf are given. Five sets of γf are given for five different overtopping estimators, calibrated using overtopping data from the CLASH database and additional tests with Cubipod armors in non-breaking conditions. The results indicate differences up to 20% in the optimum values of γf compared to those given in the literature. Optimum roughness factors are provided for the CLASH neural network (CLNN); the CLNN was found to be a better overtopping estimator than the other four overtopping formulas compared in this study. The γf is dependent on both the overtopping estimator and the dataset used. Armor porosity affects not only armor roughness and overtopping but also armor hydraulic stability; thus, recommended packing densities must be followed to avoid changes in porosity during lifetime. The sensitivity of the overtopping prediction to the roughness factor depends on the relative crest freeboard (Rc/Hm0); the greater the Rc/Hm0, the higher the sensitivity.The authors are grateful for financial support from Spanish Ministerio de Economia y Competitividad (Grant BIA2012-33967). The first author was funded through the FPU program (Formacion del Profesorado Universitario, Grant AP2010-4366) by the Spanish Ministerio de Educacion, Cultura y Deporte. The authors also thank Debra Westall for revising the manuscript.Molines, J.; Medina Folgado, JR. (2015). Calibration of overtopping roughness factors for concrete armor units in non-breaking conditions using the CLASH database. Coastal Engineering. 96:62-70. https://doi.org/10.1016/j.coastaleng.2014.11.008S62709