22 research outputs found
FGF4 retrogene on CFA12 is responsible for chondrodystrophy and intervertebral disc disease in dogs.
Chondrodystrophy in dogs is defined by dysplastic, shortened long bones and premature degeneration and calcification of intervertebral discs. Independent genome-wide association analyses for skeletal dysplasia (short limbs) within a single breed (PBonferroni = 0.01) and intervertebral disc disease (IVDD) across breeds (PBonferroni = 4.0 × 10-10) both identified a significant association to the same region on CFA12. Whole genome sequencing identified a highly expressed FGF4 retrogene within this shared region. The FGF4 retrogene segregated with limb length and had an odds ratio of 51.23 (95% CI = 46.69, 56.20) for IVDD. Long bone length in dogs is a unique example of multiple disease-causing retrocopies of the same parental gene in a mammalian species. FGF signaling abnormalities have been associated with skeletal dysplasia in humans, and our findings present opportunities for both selective elimination of a medically and financially devastating disease in dogs and further understanding of the ever-growing complexity of retrogene biology
Extracellular Fibrils of Pathogenic Yeast Cryptococcus gattii Are Important for Ecological Niche, Murine Virulence and Human Neutrophil Interactions
Cryptococcus gattii, an emerging fungal pathogen of humans and animals, is found on a variety of trees in tropical and temperate regions. The ecological niche and virulence of this yeast remain poorly defined. We used Arabidopsis thaliana plants and plant-derived substrates to model C. gattii in its natural habitat. Yeast cells readily colonized scratch-wounded plant leaves and formed distinctive extracellular fibrils (40–100 nm diameter ×500–3000 nm length). Extracellular fibrils were observed on live plants and plant-derived substrates by scanning electron microscopy (SEM) and by high voltage- EM (HVEM). Only encapsulated yeast cells formed extracellular fibrils as a capsule-deficient C. gattii mutant completely lacked fibrils. Cells deficient in environmental sensing only formed disorganized extracellular fibrils as apparent from experiments with a C. gattii STE12α mutant. C. gattii cells with extracellular fibrils were more virulent in murine model of pulmonary and systemic cryptococcosis than cells lacking fibrils. C. gattii cells with extracellular fibrils were also significantly more resistant to killing by human polymorphonuclear neutrophils (PMN) in vitro even though these PMN produced elaborate neutrophil extracellular traps (NETs). These observations suggest that extracellular fibril formation could be a structural adaptation of C. gattii for cell-to-cell, cell-to-substrate and/or cell-to- phagocyte communications. Such ecological adaptation of C. gattii could play roles in enhanced virulence in mammalian hosts at least initially via inhibition of host PMN– mediated killing
Quantitative 18F-AV1451 Brain Tau PET Imaging in Cognitively Normal Older Adults, Mild Cognitive Impairment, and Alzheimer's Disease Patients
Recent developments of tau Positron Emission Tomography (PET) allows assessment of regional neurofibrillary tangles (NFTs) deposition in human brain. Among the tau PET molecular probes, 18F-AV1451 is characterized by high selectivity for pathologic tau aggregates over amyloid plaques, limited non-specific binding in white and gray matter, and confined off-target binding. The objectives of the study are (1) to quantitatively characterize regional brain tau deposition measured by 18F-AV1451 PET in cognitively normal older adults (CN), mild cognitive impairment (MCI), and AD participants; (2) to evaluate the correlations between cerebrospinal fluid (CSF) biomarkers or Mini-Mental State Examination (MMSE) and 18F-AV1451 PET standardized uptake value ratio (SUVR); and (3) to evaluate the partial volume effects on 18F-AV1451 brain uptake.Methods: The study included total 115 participants (CN = 49, MCI = 58, and AD = 8) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Preprocessed 18F-AV1451 PET images, structural MRIs, and demographic and clinical assessments were downloaded from the ADNI database. A reblurred Van Cittertiteration method was used for voxelwise partial volume correction (PVC) on PET images. Structural MRIs were used for PET spatial normalization and region of interest (ROI) definition in standard space. The parametric images of 18F-AV1451 SUVR relative to cerebellum were calculated. The ROI SUVR measurements from PVC and non-PVC SUVR images were compared. The correlation between ROI 18F-AV1451 SUVR and the measurements of MMSE, CSF total tau (t-tau), and phosphorylated tau (p-tau) were also assessed.Results:18F-AV1451 prominently specific binding was found in the amygdala, entorhinal cortex, parahippocampus, fusiform, posterior cingulate, temporal, parietal, and frontal brain regions. Most regional SUVRs showed significantly higher uptake of 18F-AV1451 in AD than MCI and CN participants. SUVRs of small regions like amygdala, entorhinal cortex and parahippocampus were statistically improved by PVC in all groups (p < 0.01). Although there was an increasing tendency of 18F-AV-1451 SUVRs in MCI group compared with CN group, no significant difference of 18F-AV1451 deposition was found between CN and MCI brains with or without PVC (p > 0.05). Declined MMSE score was observed with increasing 18F-AV1451 binding in amygdala, entorhinal cortex, parahippocampus, and fusiform. CSF p-tau was positively correlated with 18F-AV1451 deposition. PVC improved the results of 18F-AV-1451 tau deposition and correlation studies in small brain regions.Conclusion: The typical deposition of 18F-AV1451 tau PET imaging in AD brain was found in amygdala, entorhinal cortex, fusiform and parahippocampus, and these regions were strongly associated with cognitive impairment and CSF biomarkers. Although more deposition was observed in MCI group, the 18F-AV-1451 PET imaging could not differentiate the MCI patients from CN population. More tau deposition related to decreased MMSE score and increased level of CSF p-tau, especially in ROIs of amygdala, entorhinal cortex and parahippocampus. PVC did improve the results of tau deposition and correlation studies in small brain regions and suggest to be routinely used in 18F-AV1451 tau PET quantification
A GWAS on Helicobacter pylori strains points to genetic variants associated with gastric cancer risk
International audienceBACKGROUND:Helicobacter pylori are stomach-dwelling bacteria that are present in about 50% of the global population. Infection is asymptomatic in most cases, but it has been associated with gastritis, gastric ulcers and gastric cancer. Epidemiological evidence shows that progression to cancer depends upon the host and pathogen factors, but questions remain about why cancer phenotypes develop in a minority of infected people. Here, we use comparative genomics approaches to understand how genetic variation amongst bacterial strains influences disease progression.RESULTS:We performed a genome-wide association study (GWAS) on 173 H. pylori isolates from the European population (hpEurope) with known disease aetiology, including 49 from individuals with gastric cancer. We identified SNPs and genes that differed in frequency between isolates from patients with gastric cancer and those with gastritis. The gastric cancer phenotype was associated with the presence of babA and genes in the cag pathogenicity island, one of the major virulence determinants of H. pylori, as well as non-synonymous variations in several less well-studied genes. We devised a simple risk score based on the risk level of associated elements present, which has the potential to identify strains that are likely to cause cancer but will require refinement and validation.CONCLUSION:There are a number of challenges to applying GWAS to bacterial infections, including the difficulty of obtaining matched controls, multiple strain colonization and the possibility that causative strains may not be present when disease is detected. Our results demonstrate that bacterial factors have a sufficiently strong influence on disease progression that even a small-scale GWAS can identify them. Therefore, H. pylori GWAS can elucidate mechanistic pathways to disease and guide clinical treatment options, including for asymptomatic carriers
Recommended from our members
Pain management for blunt thoracic trauma: A joint practice management guideline from the Eastern Association for the Surgery of Trauma and Trauma Anesthesiology Society
Thoracic trauma is the second most prevalent nonintentional injury in the United States and is associated with significant morbidity. Analgesia for blunt thoracic trauma was first addressed by the Eastern Association for the Surgery of Trauma (EAST) with a practice management guideline published in 2005. Since that time, it was hypothesized that there have been advances in the analgesic management for blunt thoracic trauma. As a result, updated guidelines for this topic using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) framework recently adopted by EAST are presented.
Five systematic reviews were conducted using multiple databases. The search retrieved articles regarding analgesia for blunt thoracic trauma from January1967 to August 2015. Critical outcomes of interest were analgesia, postoperative pulmonary complications, changes in pulmonary function tests, need for endotracheal intubation, and mortality. Important outcomes of interest examined included hospital and intensive care unit length of stay.
Seventy articles were identified. Of these, 28 articles were selected to construct the guidelines. The overall risk of bias for all studies was high. The majority of included studies examined epidural analgesia. Epidural analgesia was associated with lower short-term pain scores in most studies, but the quality and quantity of evidence were very low, and no firm evidence of benefit or harm was found when this modality was compared with other analgesic interventions. The quality of evidence for paravertebral block, intrapleural analgesia, multimodal analgesia, and intercostal nerve blocks was very low as assessed by GRADE. The limitations with the available literature precluded the formulation of strong recommendations by our panel.
We propose two evidence-based recommendations regarding analgesia for patients with blunt thoracic trauma. The overall risk of bias for all studies was high. The limitations with the available literature precluded the formulation of strong recommendations by our panel. We conditionally recommend epidural analgesia and multimodal analgesia as options for patients with blunt thoracic trauma, but the overall quality of evidence supporting these modalities is low in trauma patients. These recommendations are based on very low-quality evidence but place a high value on patient preferences for analgesia. These recommendations are in contradistinction to the previously published Practice Management Guideline published by EAST
Additional file 2: of A GWAS on Helicobacter pylori strains points to genetic variants associated with gastric cancer risk
Figure S2. Distribution of the GWAS hits in the 4 accessory genes used in calculation of a risk score. All the hits with a p value <â0.05 are represented in the figure. Positions are based on the ELS37 genome (GCA_000255955.1). (PDF 93 kb
Additional file 5: of A GWAS on Helicobacter pylori strains points to genetic variants associated with gastric cancer risk
Table S1. Isolate details for the global 565 strains dataset. Summary of geographic provenance, fineSTRUCTURE population and source for the global dataset of 565 strains. Table S2. Isolate details for the hpEurope GWAS dataset. Summary of metadata for the 173 strains used in the GWAS study. Host pathology, GWAS group, isolation country, isolation city or region and H. pylori population are given when available. Table S3. List of the 32 genes highlighted in at least one of the GWAS experiments. The minimum p value and an annotation (obtained by Prokka) is mentioned for each gene. (DOCX 89 kb