231 research outputs found
Quantum degeneracy in mesoscopic matter: Casimir effect and Bose-Einstein condensation
The ground-state phonon pressure is an analogue to the famous Casimir
pressure of vacuum produced by zero-point photons. The acoustic Casimir forces
are, however, many orders of magnitude weaker than the electromagnetic Casimir
forces, as the typical speed of sound is 100 000 times smaller than the speed
of light. Because of its weakness, zero-point acoustic Casimir pressure was
never observed, although the pressure of artificially introduced sound noise on
a narrow aperture has been reported. However, the magnitude of Casimir pressure
increases as with the decrease of the sample size , and reaches
picoNewtons in the sub-micron scales. We demonstrate and measure the acoustic
Casimir pressure induced by zero-point phonons in solid helium adsorbed on a
carbon nanotube. We have also observed Casimir-like "pushing out" thermal
phonons with the decreasing temperature or the length. We also show that all
thermodynamic quantities are size-dependent, and therefore in the mesoscopic
range quadruple points are possible on the phase
diagram where four different phases coexist. Due to the smallness of solid
helium sample, temperature of Bose-Einstein condensation (BEC) of vacancies is
relatively high, mK. This allowed us to experimentally discover the
BEC in a system of zero-point vacancies, predicted more than 50 years ago
Redo ventral rectopexy : is it worthwhile?
Background Minimally invasive ventral mesh rectopexy (VMR) is a widely used surgical treatment for posterior pelvic organ prolapse; however, evidence of the utility of revisional surgery is lacking. Our aim was to assess the technical details, safety and outcomes of redo minimally invasive VMR for patients with external rectal prolapse (ERP) recurrence or relapsed symptoms of internal rectal prolapse (IRP). Methods This is a retrospective cohort study of patients with recurrent ERP or symptomatic IRP who underwent redo minimally invasive VMR between 2011 and 2016. The study was conducted at three hospitals in Finland. Data collected retrospectively included patient demographics, in addition to perioperative and short-term postoperative findings. At follow-up, all living patients were sent a questionnaire concerning postoperative disease-related symptoms and quality of life. Results A total of 43 redo minimally invasive VMR were performed during the study period. The indication for reoperation was recurrent ERP in 22 patients and relapsed symptoms of IRP in 21 patients. In most operations (62.8%), the previously used mesh was left in situ and a new one was placed. Ten (23.3%) patients experienced complications, including 2 (4.7%) mesh-related complications. The recurrence rate was 4.5% for ERP. Three patients out of 43 were reoperated on for various reasons. One patient required postoperative laparoscopic hematoma evacuation. Patients operated on for recurrent ERP seemed to benefit more from the reoperation. Conclusions Minimally invasive redo VMR appears to be a safe and effective procedure for treating posterior pelvic floor dysfunction with acceptable recurrence and reoperation rates.Peer reviewe
ANO7 rs77559646 Is Associated With First-line Docetaxel Treatment Response in Metastatic Castration-resistant Prostate Cancer
Background: Identification of genetic prognostic biomarkers, such as germline variants, are urgently needed to choose optimal treatment for metastatic castration-resistant prostate cancer (mCRPC). Patients and Methods: The prognostic value of anoctamin 7 (ANO7) rs77559646 on docetaxel response was tested in a prospective PROSTY randomized trial and a retrospective Auria Biobank set. The variant rs77559646 was genotyped and its association with progression-free survival (PFS) and overall survival (OS) was tested. Results: In comparison with the non-carriers, the variant carriers had longer PFS (p=0.005) and OS (p=0.003) in the PROSTY cohort. In the retrospective cohort, there was a borderline association with PFS (p=0.09), but not in OS (p=0.9). In both cohorts, Cox regression multivariate models revealed that rs77559646 was an independent prognostic factor for favourable PFS. Conclusion: The rs77559646 was shown to be a prognostic germline biomarker for better response to docetaxel treatments. To our knowledge, this is the first time that a non-coding germline variant has been associated with chemotherapy of mCRPC
Metabolic profiling of fatty liver in young and middle-aged adults : Cross-sectional and prospective analyses of the Young Finns Study
Nonalcoholic fatty liver is associated with obesity-related metabolic disturbances, but little is known about the metabolic perturbations preceding fatty liver disease. We performed comprehensive metabolic profiling to assess how circulating metabolites, such as lipoprotein lipids, fatty acids, amino acids, and glycolysis-related metabolites, reflect the presence of and future risk for fatty liver in young adults. Sixty-eight lipids and metabolites were quantified by nuclear magnetic resonance metabolomics in the population-based Young Finns Study from serum collected in 2001 (n = 1,575), 2007 (n = 1,509), and 2011 (n = 2,002). Fatty liver was diagnosed by ultrasound in 2011 when participants were aged 34-49 years (19% prevalence). Cross-sectional associations as well as 4-year and 10-year risks for fatty liver were assessed by logistic regression. Metabolites across multiple pathways were strongly associated with the presence of fatty liver (P <0.0007 for 60 measures in age-adjusted and sex-adjusted cross-sectional analyses). The strongest direct associations were observed for extremely large very-low-density lipoprotein triglycerides (odds ratio [OR] = 4.86 per 1 standard deviation, 95% confidence interval 3.48-6.78), other very-low-density lipoprotein measures, and branched-chain amino acids (e.g., leucine OR = 2.94, 2.51-3.44). Strong inverse associations were observed for high-density lipoprotein measures, e.g., high-density lipoprotein size (OR = 0.36, 0.30-0.42) and several fatty acids including omega-6 (OR = 0.37, 0.32-0.42). The metabolic associations were attenuated but remained significant after adjusting for waist, physical activity, alcohol consumption, and smoking (P <0.0007). Similar aberrations in the metabolic profile were observed already 10 years before fatty liver diagnosis. Conclusion: Circulating lipids, fatty acids, and amino acids reflect fatty liver independently of routine metabolic risk factors; these metabolic aberrations appear to precede the development of fatty liver in young adults. (Hepatology 2017;65:491-500).Peer reviewe
Microanatomy of the Human Atherosclerotic Plaque by Single-Cell Transcriptomics
RATIONALE: Atherosclerotic lesions are known for their cellular heterogeneity, yet the molecular complexity within the cells of
human plaques has not been fully assessed.
OBJECTIVE: Using single-cell transcriptomics and chromatin accessibility, we gained a better understanding of the
pathophysiology underlying human atherosclerosis.
METHODS AND RESULTS: We performed single-cell RNA and single-cell ATAC sequencing on human carotid atherosclerotic
plaques to define the cells at play and determine their transcriptomic and epigenomic characteristics. We identified 14
distinct cell populations including endothelial cells, smooth muscle cells, mast cells, B cells, myeloid cells, and T cells and
identified multiple cellular activation states and suggested cellular interconversions. Within the endothelial cell population,
we defined subsets with angiogenic capacity plus clear signs of endothelial to mesenchymal transition. CD4+ and CD8+
T cells showed activation-based subclasses, each with a gradual decline from a cytotoxic to a more quiescent phenotype.
Myeloid cells included 2 populations of proinflammatory macrophages showing IL (interleukin) 1B or TNF (tumor necrosis
factor) expression as well as a foam cell-like population expressing TREM2 (triggering receptor expressed on myeloid
cells 2) and displaying a fibrosis-promoting phenotype. ATACseq data identified specific transcription factors associated
with the myeloid subpopulation and T cell cytokine profiles underlying mutual activation between both cell types. Finally,
cardiovascular disease susceptibility genes identified using public genome-wide association studies data were particularly
enriched in lesional macrophages, endothelial, and smooth muscle cells.
CONCLUSIONS: This study provides a transcriptome-based cellular landscape of human atherosclerotic plaques and highlights
cellular plasticity and intercellular communication at the site of disease. This detailed definition of cell communities at play
in atherosclerosis will facilitate cell-based mapping of novel interventional targets with direct functional relevance for the
treatment of human diseas
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Integrative analysis of liver-specific non-coding regulatory SNPs associated with the risk of coronary artery disease
Genetic factors underlying coronary artery disease (CAD) have been widely studied using genome-wide association studies (GWASs). However, the functional understanding of the CAD loci has been limited by the fact that a majority of GWAS variants are located within non-coding regions with no functional role. High cholesterol and dysregulation of the liver metabolism such as non-alcoholic fatty liver disease confer an increased risk of CAD. Here, we studied the function of non-coding single-nucleotide polymorphisms in CAD GWAS loci located within liver-specific enhancer elements by identifying their potential target genes using liver cis-eQTL analysis and promoter Capture Hi-C in HepG2 cells. Altogether, 734 target genes were identified of which 121 exhibited correlations to liver-related traits. To identify potentially causal regulatory SNPs, the allele-specific enhancer activity was analyzed by (1) sequence-based computational predictions, (2) quantification of allele-specific transcription factor binding, and (3) STARR-seq massively parallel reporter assay. Altogether, our analysis identified 1,277 unique SNPs that display allele-specific regulatory activity. Among these, susceptibility enhancers near important cholesterol homeostasis genes (APOB, APOC1, APOE, and LIPA) were identified, suggesting that altered gene regulatory activity could represent another way by which genetic variation regulates serum lipoprotein levels. Using CRISPR-based perturbation, we demonstrate how the deletion/activation of a single enhancer leads to changes in the expression of many target genes located in a shared chromatin interaction domain. Our integrative genomics approach represents a comprehensive effort in identifying putative causal regulatory regions and target genes that could predispose to clinical manifestation of CAD by affecting liver function
EWS-FLI1Â Utilizes Divergent Chromatin Remodeling Mechanisms to Directly Activate or Repress Enhancer Elements in Ewing Sarcoma
SummaryThe aberrant transcription factor EWS-FLI1 drives Ewing sarcoma, but its molecular function is not completely understood. We find that EWS-FLI1 reprograms gene regulatory circuits in Ewing sarcoma by directly inducing or repressing enhancers. At GGAA repeat elements, which lack evolutionary conservation and regulatory potential in other cell types, EWS-FLI1 multimers induce chromatin opening and create de novo enhancers that physically interact with target promoters. Conversely, EWS-FLI1 inactivates conserved enhancers containing canonical ETS motifs by displacing wild-type ETS transcription factors. These divergent chromatin-remodeling patterns repress tumor suppressors and mesenchymal lineage regulators while activating oncogenes and potential therapeutic targets, such as the kinase VRK1. Our findings demonstrate how EWS-FLI1 establishes an oncogenic regulatory program governing both tumor survival and differentiation
Genome-wide association of familial prostate cancer cases identifies evidence for a rare segregating haplotype at 8q24.21
Previous genome-wide association studies (GWAS) of prostate cancer risk focused on cases unselected for family history and have reported over 100 significant associations. The International Consortium for Prostate Cancer Genetics (ICPCG) has now performed a GWAS of 2511 (unrelated) familial prostate cancer cases and 1382 unaffected controls from 12 member sites. All samples were genotyped on the Illumina 5M+exome single nucleotide polymorphism (SNP) platform. The GWAS identified a significant evidence for association for SNPs in six regions previously associated with prostate cancer in population-based cohorts, including 3q26.2, 6q25.3, 8q24.21, 10q11.23, 11q13.3, and 17q12. Of note, SNP rs138042437 (p = 1.7eâ8) at 8q24.21 achieved a large estimated effect size in this cohort (odds ratio = 13.3). 116 previously sampled affected relatives of 62 risk-allele carriers from the GWAS cohort were genotyped for this SNP, identifying 78 additional affected carriers in 62 pedigrees. A test for an excess number of affected carriers among relatives exhibited strong evidence for co-segregation of the variant with disease (p = 8.5eâ11). The majority (92 %) of risk-allele carriers at rs138042437 had a consistent estimated haplotype spanning approximately 100 kb of 8q24.21 that contained the minor alleles of three rare SNPs (dosage minor allele frequencies <1.7 %), rs183373024 (PRNCR1), previously associated SNP rs188140481, and rs138042437 (CASC19). Strong evidence for co-segregation of a SNP on the haplotype further characterizes the haplotype as a prostate cancer pre-disposition locus
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