Can MRI T1 be used to detect early changes in 5xFAD Alzheimer’s mouse brain?

In the present study, we have tested whether MRI T1 relaxation time is a sensitive marker to detect early stages of amyloidosis and gliosis in the young 5xFAD transgenic mouse, a well-established animal model for Alzheimer's disease.5xFAD and wild-type mice were imaged in a 4.7 T Varian horizontal bore MRI system to generate T1 quantitative maps using the spin-echo multi-slice sequence. Following immunostaining for glial fibrillary acidic protein, Iba-1, and amyloid-β, T1 and area fraction of staining were quantified in the posterior parietal and primary somatosensory cortex and corpus callosum.In comparison with age-matched wild-type mice, we observed first signs of amyloidosis in 2.5-month-old 5xFAD mice, and development of gliosis in 5-month-old 5xFAD mice. In contrast, MRI T1 relaxation times of young, i.e., 2.5- and 5-month-old, 5xFAD mice were not significantly different to those of age-matched wild-type controls. Furthermore, although disease progression was detectable by increased amyloid-β load in the brain of 5-month-old 5xFAD mice compared with 2.5-month-old 5xFAD mice, MRI T1 relaxation time did not change.In summary, our data suggest that MRI T1 relaxation time is neither a sensitive measure of disease onset nor progression at early stages in the 5xFAD mouse transgenic mouse model

Analysis of historical negative control group data from the in vitro micronucleus assay using human lymphocytes.

A database of the micronuclei counts was built up for historical negative control data from human lymphocyte in vitro micronuclei tests (MnVit) carried out in 8 laboratories with experience of the method. The mean incidence of micronucleated cells (mnt)/1000 cells ranged from 2.2/1000 to 15.9/1000. There were no large differences in incidence between the presence or absence of S9 mix or between different treatment lengths. There was also little evidence that different solvents affected the numbers of micronuclei appreciably. A number of laboratories did show significant inter-experiment variability, indicating that there remained unidentified factors affecting frequencies. Donor variance may be one such factor. Inter-individual variability may explain some of these differences. The approximate 7.5-fold difference in mnt/1000 scores in a relatively small group of experienced laboratories illustrates the potential complications that can arise if a metric like a fold increase was considered the only biologically important finding. Although there is inherent variability between experiments, it was evident that within a laboratory the overall laboratory mean remains constant over time. It is believed that these findings will provide help to laboratories conducting studies using human lymphocytes in the MnVit and to those involved in the assessment of MnVit results

A comparison of transgenic rodent mutation and in vivo comet assay responses for 91 chemicals.

A database of 91 chemicals with published data from both transgenic rodent mutation (TGR) and rodent comet assays has been compiled. The objective was to compare the sensitivity of the two assays for detecting genotoxicity. Critical aspects of study design and results were tabulated for each dataset. There were fewer datasets from rats than mice, particularly for the TGR assay, and therefore, results from both species were combined for further analysis. TGR and comet responses were compared in liver and bone marrow (the most commonly studied tissues), and in stomach and colon evaluated either separately or in combination with other GI tract segments. Overall positive, negative, or equivocal test results were assessed for each chemical across the tissues examined in the TGR and comet assays using two approaches: 1) overall calls based on weight of evidence (WoE) and expert judgement, and 2) curation of the data based on a priori acceptability criteria prior to deriving final tissue specific calls. Since the database contains a high prevalence of positive results, overall agreement between the assays was determined using statistics adjusted for prevalence (using AC1 and PABAK). These coefficients showed fair or moderate to good agreement for liver and the GI tract (predominantly stomach and colon data) using WoE, reduced agreement for stomach and colon evaluated separately using data curation, and poor or no agreement for bone marrow using both the WoE and data curation approaches. Confidence in these results is higher for liver than for the other tissues, for which there were less data. Our analysis finds that comet and TGR generally identify the same compounds (mainly potent mutagens) as genotoxic in liver, stomach and colon, but not in bone marrow. However, the current database content precluded drawing assay concordance conclusions for weak mutagens and non-DNA reactive chemicals

Recommendations for conducting the rodent erythrocyte Pig-a assay: A report from the HESI GTTC Pig-a Workgroup.

The rodent Pig-a assay is a flow cytometric, phenotype-based method used to measure in vivo somatic cell mutation. An Organization for Economic Co-operation and Development (OECD) test guideline is currently being developed to support routine use of the assay for regulatory purposes (OECD project number 4.93). This article provides advice on best practices for designing and conducting rodent Pig-a studies in support of evaluating test substance safety, with a focus on the rat model. Various aspects of assay conduct, including laboratory proficiency, minimum number of animals per dose group, preferred treatment and blood sampling schedule, and statistical analysis are described

Human blood PIG-A mutation and micronucleated reticulocyte flow cytometric assays: Method optimization and evaluation of intra- and inter-subject variation.

We previously described flow cytometry-based methods for scoring the incidence of micronucleated reticulocytes (MN-RET) and PIG-A mutant phenotype reticulocytes (MUT RET) in rodent and human blood samples. The current report describes important methodological improvements for human blood analyses, including immunomagnetic enrichment of CD71-positive reticulocytes prior to MN-RET scoring, and procedures for storing frozen blood for later PIG-A analysis. Technical replicate variability in MN-RET and MUT RET frequencies based on blood specimens from 14 subjects, intra-subject variability based on serial blood draws from 6 subjects, and inter-subject variation based on up to 344 subjects age 0 to 73 years were quantified. Inter-subject variation explained most of the variability observed for both endpoints (≥ 77%), with much lower intra-subject and technical replicate variability. The relatively large degree of inter-subject variation is apparent from mean and standard deviation values for MN-RET (0.15 ± 0.10%) and MUT RET (4.7 ± 5.0 per million, after omission of two extreme outliers). The influences of age and sex on inter-subject variation were investigated, and neither factor affected MN-RET whereas both influenced MUT RET frequency. The lowest MUT RET values were observed for subjects < 11 years old, and males had moderately higher frequencies than females. These results indicate that MN-RET and MUT RET are automation-compatible biomarkers of genotoxicity that bridge species of toxicological interest to include human populations. These data will be useful for appropriately designing future human studies that include these biomarkers of genotoxicity, and highlight the need for additional work aimed at identifying the sources of inter-individual variability reported herein

Patient-reported improvements in health are maintained 2 years after completing a short course of cognitive behaviour therapy, exercise or both treatments for chronic widespread pain: long-term results from the MUSICIAN randomised controlled trial

Objectives The MUSICIAN study has previously shown short-term benefit but only marginal cost-effectiveness for two non-pharmacological interventions for chronic widespread pain (CWP). We wished to determine their long-term effectiveness and cost-effectiveness. Methods A 2×2 factorial randomised controlled trial based in primary care in the UK. People were eligible if they were aged ≥25 years with CWP for which they had consulted their general practitioner. The interventions were a 6-month telephone cognitive behaviour therapy (tCBT) and/or a tailored exercise programme, in comparison to usual care. The primary outcome was patient-reported change in health. Results 884 persons were eligible, 442 were randomised and 81.7% were followed up 24 months post-treatment. In comparison to usual care (positive outcome 12.8%), tCBT (35.4%; OR 3.7 95% CI (1.8 to 8.0)), exercise (29.3%; OR 2.8 95% CI (1.3 to 6.0)) and both interventions (31.2%; OR 3.1 95% CI (1.3 to 6.0)) were significantly more effective. There was only a small decrease in effectiveness over time for individual and combined treatments. Those with more intense/disabling pain, higher distress and those who exhibited passive coping at baseline were more likely to have a positive outcome with tCBT than persons without these characteristics. tCBT was associated with the greatest increase in quality of life and lowest costs. Cost per quality adjusted life year was £3957–£5917 depending on method of analysis. Conclusions A short course of tCBT for people with CWP was effective long-term and was highly cost-effective. Exercise was also effective but delivered positive outcome for fewer patients at greater cost, and there was no advantage for patients receiving both interventions

A perspective on the measurement of time in plant disease epidemiology

The growth and development of plant pathogens and their hosts generally respond strongly to the temperature of their environment. However, most studies of plant pathology record pathogen/host measurements against physical time (e.g. hours or days) rather than thermal time (e.g. degree-days or degree-hours). This confounds the comparison of epidemiological measurements across experiments and limits the value of the scientific literature

Determination of consensus among professionals for community safety terms through a Delphi study

This is a post-peer-review, pre-copyedit version of an article published in Crime Prevention and Community Safety. The definitive publisher-authenticated version 2013, 15(4), pp. 258-277 is available online at: http://dx.doi.org/10.1057/cpcs.2013.9This article reports the findings from a study of Community Safety professionals (Academics, Policymakers and Practitioners), using the Delphi method to determine common definitions, if any, for Community Safety terms in current usage. The study investigated the differences in the way that the terms were used and understood by the members of the three groups. The study was predicated on the view that the groups of Community Safety professionals probably use the language of Community Safety in different ways. It is suggested that work in the field would benefit from a shared terminology, where the same term has the same meaning for different professional groups

DNA Electrophoretic Migration Patterns Change after Exposure of Jurkat Cells to a Single Intense Nanosecond Electric Pulse

Intense nanosecond pulsed electric fields (nsPEFs) interact with cellular membranes and intracellular structures. Investigating how cells respond to nanosecond pulses is essential for a) development of biomedical applications of nsPEFs, including cancer therapy, and b) better understanding of the mechanisms underlying such bioelectrical effects. In this work, we explored relatively mild exposure conditions to provide insight into weak, reversible effects, laying a foundation for a better understanding of the interaction mechanisms and kinetics underlying nsPEF bio-effects. In particular, we report changes in the nucleus of Jurkat cells (human lymphoblastoid T cells) exposed to single pulses of 60 ns duration and 1.0, 1.5 and 2.5 MV/m amplitudes, which do not affect cell growth and viability. A dose-dependent reduction in alkaline comet-assayed DNA migration is observed immediately after nsPEF exposure, accompanied by permeabilization of the plasma membrane (YO-PRO-1 uptake). Comet assay profiles return to normal within 60 minutes after pulse delivery at the highest pulse amplitude tested, indicating that our exposure protocol affects the nucleus, modifying DNA electrophoretic migration patterns