Subcellular compartmentalisation of copper, iron, manganese, and zinc in the Parkinson's disease brain

© 2017 The Royal Society of Chemistry. Elevated iron and decreased copper levels are cardinal features of the degenerating substantia nigra pars compacta in the Parkinson's disease brain. Both of these redox-active metals, and fellow transition metals manganese and zinc, are found at high concentrations within the midbrain and participate in a range of unique biological reactions. We examined the total metal content and cellular compartmentalisation of manganese, iron, copper and zinc in the degenerating substantia nigra, disease-affected but non-degenerating fusiform gyrus, and unaffected occipital cortex in the post mortem Parkinson's disease brain compared with age-matched controls. An expected increase in iron and a decrease in copper concentration was isolated to the soluble cellular fraction, encompassing both interstitial and cytosolic metals and metal-binding proteins, rather than the membrane-associated or insoluble fractions. Manganese and zinc levels did not differ between experimental groups. Altered Fe and Cu levels were unrelated to Braak pathological staging in our cases of late-stage (Braak stage V and VI) disease. The data supports our hypothesis that regional alterations in Fe and Cu, and in proteins that utilise these metals, contribute to the regional selectively of neuronal vulnerability in this disorder

Short acquisition time PET quantification using MRI-based pharmacokinetic parameter synthesis

Positron Emission Tomography (PET) with pharmacokinetic (PK) modelling is a quantitative molecular imaging technique, however the long data acquisition time is prohibitive in clinical practice. An approach has been proposed to incorporate blood flow information from Arterial Spin Labelling (ASL) Magnetic Resonance Imaging (MRI) into PET PK modelling to reduce the acquisition time. This requires the conversion of cerebral blood flow (CBF) maps, measured by ASL, into the relative tracer delivery parameter (R 1 ) used in the PET PK model. This was performed regionally using linear regression between population R 1 and ASL values. In this paper we propose a novel technique to synthesise R 1 maps from ASL data using a database with both R 1 and CBF maps. The local similarity between the candidate ASL image and those in the database is used to weight the propagation of R 1 values to obtain the optimal patient specific R 1 map. Structural MRI data is also included to provide information within common regions of artefact in ASL data. This methodology is compared to the linear regression technique using leave one out analysis on 32 subjects. The proposed method significantly improves regional R 1 estimation (p < 0.001), reducing the error in the pharmacokinetic modelling. Furthermore, it allows this technique to be extended to a voxel level, increasing the clinical utility of the images

Vaccination against Foot-and-mouth disease : do initial conditions affect its benefit?

When facing incursion of a major livestock infectious disease, the decision to implement a vaccination programme is made at the national level. To make this decision, governments must consider whether the benefits of vaccination are sufficient to outweigh potential additional costs, including further trade restrictions that may be imposed due to the implementation of vaccination. However, little consensus exists on the factors triggering its implementation on the field. This work explores the effect of several triggers in the implementation of a reactive vaccination-to-live policy when facing epidemics of foot-and-mouth disease. In particular, we tested whether changes in the location of the incursion and the delay of implementation would affect the epidemiological benefit of such a policy in the context of Scotland. To reach this goal, we used a spatial, premises-based model that has been extensively used to investigate the effectiveness of mitigation procedures in Great Britain. The results show that the decision to vaccinate, or not, is not straightforward and strongly depends on the underlying local structure of the population-at-risk. With regards to disease incursion preparedness, simply identifying areas of highest population density may not capture all complexities that may influence the spread of disease as well as the benefit of implementing vaccination. However, if a decision to vaccinate is made, we show that delaying its implementation in the field may markedly reduce its benefit. This work provides guidelines to support policy makers in their decision to implement, or not, a vaccination-to-live policy when facing epidemics of infectious livestock disease

Single Parenting and Child Behavior Problems in Kindergarten

Two waves of data from a sample of 89 poor and near-poor single black mothers and their preschool children were used to study the influences of parenting stress, physical discipline practices, and nonresident fathers’ relations with their children on behavior problems in kindergarten. The results indicate that higher levels of parent stress, more frequent spanking, and less frequent father–child contact at time 1 were associated with increased teacher-reported behavior problems at time 2. In addition, more frequent contact between nonresident biological fathers and their children moderated the negative effect of harsh discipline by mothers on subsequent child behavior problems. Specifically, when contact with the father was low, maternal spanking resulted in elevated levels of behavior problems; with average contact, this negative effect of spanking was muted; and with high contact, spanking was not associated with increased behavior problems in kindergarten. The implications of these findings for future research and policy are discussed

Analysis of Variance in Neuroreceptor Ligand Imaging Studies

Radioligand positron emission tomography (PET) with dual scan paradigms can provide valuable insight into changes in synaptic neurotransmitter concentration due to experimental manipulation. The residual t-test has been utilized to improve the sensitivity of the t-test in PET studies. However, no further development of statistical tests using residuals has been proposed so far to be applied in cases when there are more than two conditions. Here, we propose the residual f-test, a one-way analysis of variance (ANOVA), and examine its feasibility using simulated [11C]raclopride PET data. We also re-visit data from our previously published [11C]raclopride PET study, in which 10 individuals underwent three PET scans under different conditions. We found that the residual f-test is superior in terms of sensitivity than the conventional f-test while still controlling for type 1 error. The test will therefore allow us to reliably test hypotheses in the smaller sample sizes often used in explorative PET studies

Quantitative analysis of dynamic 18F-FDG PET/CT for measurement of lung inflammation

$\textbf{Background:}$ An inflammatory reaction in the airways and lung parenchyma, comprised mainly of neutrophils and alveolar macrophages, is present in some patients with chronic obstructive pulmonary disease (COPD). Thoracic fluorodeoxyglucose $^{18}$F-FDG) positron emission tomography (PET) has been proposed as a promising imaging biomarker to assess this inflammation. We sought to introduce a fully quantitative analysis method and compare this with previously published studies based on the Patlak approach using a dataset comprising $^{18}$F-FDG PET scans from COPD subjects with elevated circulating inflammatory markers (fibrinogen) and matched healthy volunteers (HV). Dynamic $^{18}$F-FDG PET scans were obtained for high-fibrinogen (>2.8 g/l) COPD subjects (N = 10) and never smoking HV (N = 10). Lungs were segmented using co-registered computed tomography images and subregions (upper, middle and lower) were semi-automatically defined. A quantitative analysis approach was developed, which corrects for the presence of air and blood in the lung (qABL method), enabling direct estimation of the metabolic rate of FDG in lung tissue. A normalised Patlak analysis approach was also performed to enable comparison with previously published results. Effect sizes (Hedge's g) were used to compare HV and COPD groups. $\textbf{Results:}$ The qABL method detected no difference (Hedge's g = 0.15 [-0.76 1.04]) in the tissue metabolic rate of FDG in the whole lung between HV (μ = 6.0 ± 1.9 × 10$^{-3}$ ml cm$^{-3}$ min$^{-1}$) and COPD (μ = 5.7 ± 1.7 × 10$^{-3}$ ml cm$^{-3}$ min$^{-1}$). However, analysis with the normalised Patlak approach detected a significant difference (Hedge's g = -1.59 [-2.57 -0.48]) in whole lung between HV (μ = 2.9 ± 0.5 × 10$^{-3}$ ml cm$^{-3}$ min$^{-1}$) and COPD (μ = 3.9 ± 0.7 × 10$^{-3}$ ml cm$^{-3}$ min$^{-1}$). The normalised Patlak endpoint was shown to be a composite measure influenced by air volume, blood volume and actual uptake of $^{18}$F-FDG in lung tissue. $\textbf{Conclusions:}$ We have introduced a quantitative analysis method that provides a direct estimate of the metabolic rate of FDG in lung tissue. This work provides further understanding of the underlying origin of the $^{18}$F-FDG signal in the lung in disease groups and helps interpreting changes following standard or novel therapies.JC and IBW acknowledge the funding support from the Cambridge Comprehensive Biomedical Research Centre. MIP’s contribution to this work was funded by the NIHR Respiratory Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust and Imperial College who part fund his salary. EVOLUTION and EVOLVE studies were funded by Innovate UK under the ERICA consortium grant with in kind contributions from GSK

A direct physical interaction between Nanog and Sox2 regulates embryonic stem cell self-renewal

Embryonic stem (ES) cell self-renewal efficiency is determined by the Nanog protein level. However, the protein partners of Nanog that function to direct self-renewal are unclear. Here, we identify a Nanog interactome of over 130 proteins including transcription factors, chromatin modifying complexes, phosphorylation and ubiquitination enzymes, basal transcriptional machinery members, and RNA processing factors. Sox2 was identified as a robust interacting partner of Nanog. The purified Nanog–Sox2 complex identified a DNA recognition sequence present in multiple overlapping Nanog/Sox2 ChIP-Seq data sets. The Nanog tryptophan repeat region is necessary and sufficient for interaction with Sox2, with tryptophan residues required. In Sox2, tyrosine to alanine mutations within a triple-repeat motif (S X T/S Y) abrogates the Nanog–Sox2 interaction, alters expression of genes associated with the Nanog-Sox2 cognate sequence, and reduces the ability of Sox2 to rescue ES cell differentiation induced by endogenous Sox2 deletion. Substitution of the tyrosines with phenylalanine rescues both the Sox2–Nanog interaction and efficient self-renewal. These results suggest that aromatic stacking of Nanog tryptophans and Sox2 tyrosines mediates an interaction central to ES cell self-renewal

Kinetic analysis of the translocator protein positron emission tomography ligand [F-18]GE-180 in the human brain

Purpose: PET can image neuroinflammation by targeting the translocator protein (TSPO), which is upregulated in activated microglia. The high nonspecific binding of the first-generation TSPO radioligand [11C]PK-11195 limits accurate quantification. [18F]GE-180, a novel TSPO ligand, displays superior binding to [11C]PK-11195 in vitro. Our objectives were to: (1) evaluate tracer characteristics of [18F]GE-180 in the brains of healthy human subjects; and (2) investigate whether the TSPO Ala147Thr polymorphism influences outcome measures. // Methods: Ten volunteers (five high-affinity binders, HABs, and five mixed-affinity binders, MABs) underwent a dynamic PET scan with arterial sampling after injection of [18F]GE-180. Kinetic modelling of time–activity curves with one-tissue and two-tissue compartment models and Logan graphical analysis was applied to the data. The primary outcome measure was the total volume of distribution (V T) across various regions of interest (ROIs). Secondary outcome measures were the standardized uptake values (SUV), the distribution volume and SUV ratios estimated using a pseudoreference region. // Results: The two-tissue compartment model was the best model. The average regional delivery rate constant (K 1) was 0.01 mL cm−3 min−1 indicating low extraction across the blood–brain barrier (1 %). The estimated median V T across all ROIs was also low, ranging from 0.16 mL cm−3 in the striatum to 0.38 mL cm−3 in the thalamus. There were no significant differences in V T between HABs and MABs across all ROIs. // Conclusion: A reversible two-tissue compartment model fitted the data well and determined that the tracer has a low first-pass extraction (approximately 1 %) and low V T estimates in healthy individuals. There was no observable dependency on the rs6971 polymorphism as compared to other second-generation TSPO PET tracers. Investigation of [18F]GE-180 in populations with neuroinflammatory disease is needed to determine its suitability for quantitative assessment of TSPO expression

A Model of Salmonella Colitis with Features of Diarrhea in SLC11A1 Wild-Type Mice

Background: Mice do not get diarrhea when orally infected with S. enterica, but pre-treatment with oral aminoglycosides makes them susceptible to Salmonella colitis. However, genetically susceptible ItyS mice (Nramp1 G169D allele) die from systemic infection before they develop diarrhea, so a new model is needed to study the pathogenesis of diarrhea. We pretreated ItyR mice (Nramp1 G169) with oral kanamycin prior to infecting them with virulent S. Typhimurium strain 14028s in order to study Salmonella-induced diarrhea. We used both a visual scoring system and the measurement of fecal water content to measure diarrhea. BALB/c.D2 Nramp1 congenic started losing weight 5 days post-infection and they began to die from colitis 10–14 days after infection. A SPI-1 (invA) mutant caused cecal, but not colonic inflammation and did not cause diarrhea. A phoP- mutant did not cause manifestations of diarrhea in either normal or NADPHdeficient (gp91 phox) mice. However, strain 14028s caused severe colitis and diarrhea in gp91 phox-deficient mice on an ItyR background. pmr A and F mutants, which are less virulent in orally infected BALB/c mice, were fully virulent in this model of colitis. Conclusions: S. enterica must be able to invade the colonic epithelium and to persist in the colon in order to cause colitis with manifestations of diarrhea. The NADPH oxidase is not required for diarrhea in Salmonella colitis. Furthermore,

The Effect of Bifidobacterium on Reducing Symptomatic Abdominal Pain in Patients with Irritable Bowel Syndrome: A Systematic Review

Probiotics, specifically Bifidobacteria, may improve abdominal pain in patients with irritable bowel syndrome (IBS); however, results from randomised controlled trials (RCTs) are conflicting. Here, we systematically reviewed the efficacy of Bifidobacteria on abdominal pain in IBS. We searched MEDLINE, EMBASE and the Cochrane Controlled Trials Register from inception to 20 May 2019, without language or date restrictions. The search strategy comprised of the combination of three concepts: supplementation, abdominal pain, and IBS. Inclusion criteria included double-blind placebo-controlled RCTs featuring Bifidobacteria supplementation in Rome-diagnosed IBS patients. A total of 8 RCTs involving a total of 1045 patients with Rome diagnosed IBS were included. The dose of total Bifidobacteria ranged from 106 to > 1011 cfu (colony-forming unit) and duration of supplementation ranged between 2 and 8 weeks. Bifidobacteria was delivered through either intake of fermented milk products, encapsulation or via a malted milk beverage, with all studies assessing abdominal pain via a visual analogue Likert scale. From the studies included, 50% (n = 4) of studies found a statistically significant improvement in abdominal pain following Bifidobacteria supplementation compared to placebo, 38% (n = 3) of studies found non-significant improvements and 12% (n = 1) showed a statistically significant dose-response effect of improvement. The evidence shows a heterogeneity of effect for Bifidobacteria dependent upon strain, dosage and delivery method. While not all studies demonstrate significant improvements in abdominal pain, none of the selected studies reported an increase in pain or other adverse effects