338 research outputs found
Periostin Is a Novel Factor in Cardiac Remodeling After Experimental and Clinical Unloading of the Failing Heart
Maladaptive left ventricular hypertrophy (LVH) remains a prevalent and highly morbid condition associated with end-stage heart disease. Originally evaluated in the context of bone development, periostin is important in endocardial cushion formation and has recently been implicated in heart failure. Because of its potential role in cardiovascular development, we sought to establish the role of periostin after relief of pressure overload in animal and human models
IKK-β inhibition prevents adaptive left ventricular hypertrophy
Most cardiovascular studies have implicated the central transcription factor nuclear factor kappa B (NF-κB) as contributing to the detrimental effects of cardiac injury. This ostensibly negative view of NF-κB competes with its important role in the normal host inflammatory and immune response. Pressure-overload, left ventricular hypertrophy (LVH), and heart failure represent a spectrum of disease that has both adaptive and maladaptive components. As opposed to its known effects related to myocardial ischemia-reperfusion, we hypothesized that NF-κB is necessary for the compensatory phase of cardiac remodeling
Perceived physical fatigability predicts all-cause mortality in older adults
BACKGROUND: Perceived physical fatigability is highly prevalent in older adults and associated with mobility decline and other health consequences. We examined the prognostic value of perceived physical fatigability as an independent predictor of risk of death among older adults.
METHODS: Participants (N = 2 906), mean age 73.5 [SD, 10.4] years, 54.2% women, 99.7% white enrolled in the Long Life Family Study, were assessed at Visit 2 (2014-2017) with 2.7 [SD, 1.0] years follow-up. The Pittsburgh Fatigability Scale (PFS), a 10-item, self-administered validated questionnaire (score range 0-50, higher = greater fatigability) measured perceived physical fatigability at Visit 2. Deaths post-Visit 2 through December 31, 2019 were identified by family members notifying field centers, reporting during another family member\u27s annual phone follow-up, an obituary, or Civil Registration System (Denmark). We censored all other participants at their last contact. Cox proportional hazard models predicted mortality by fatigability severity, adjusted for family relatedness and other covariates.
RESULTS: Age-adjusted PFS Physical scores were higher for those who died (19.1 [SE, 0.8]) compared with alive (12.2, [SE, 0.4]) overall, as well as across age strata (p \u3c .001), except for those 60-69 years (p = .79). Participants with the most severe fatigability (PFS Physical scores ≥ 25) were over twice as likely to die (hazard ratio, 2.33 [95% CI, 1.65-3.28]) compared with those who had less severe fatigability (PFS Physical scores \u3c 25) after adjustment.
CONCLUSIONS: Our work underscores the utility of the PFS as a novel patient-reported prognostic indicator of phenotypic aging that captures both overt and underlying disease burden that predicts death
Recovery from decompensated heart failure is associated with a distinct, phase-dependent gene expression profile
Clinical and experimental studies have traditionally focused on understanding the mechanisms for why a heart fails. We hypothesize that the pathways involved with myocardial recovery are not simply the reverse of those that cause heart failure. However, determining when and how a decompensated heart can recover remains unknown
Ataxin-2 intermediate-length polyglutamine expansions in European ALS patients
Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset neurodegenerative disease primarily affecting motor neurons. We recently identified intermediate-length polyglutamine (polyQ) expansions (27-33 Qs) in ataxin 2 as a genetic risk factor for sporadic ALS in North American ALS patients. To extend these findings, we assessed the ataxin 2 polyQ repeat length in 1294 European ALS patients and 679 matched healthy controls. We observed a significant association between polyQ expansions and ALS (>30 Qs; P= 6.2 × 10−3). Thus, intermediate-length ataxin 2 polyQ repeat expansions are associated with increased risk for ALS also in the European cohort. The specific polyQ length cutoff, however, appears to vary between different populations, with longer repeat lengths showing a clear association. Our findings support the hypothesis that ataxin 2 plays an important role in predisposing to ALS and that polyQ expansions in ataxin 2 are a significant risk factor for the diseas
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Protein–Mineral Interactions: Molecular Dynamics Simulations Capture Importance of Variations in Mineral Surface Composition and Structure
Molecular dynamics simulations, conventional and metadynamics, were performed to determine the interaction of model protein Gb1 over kaolinite (001), Na⁺-montmorillonite (001), Ca²⁺-montmorillonite (001), goethite (100), and Na⁺-birnessite (001) mineral surfaces. Gb1, a small (56 residue) protein with a well-characterized solution-state nuclear magnetic resonance (NMR) structure and having α-helix, 4-fold β-sheet, and hydrophobic core features, is used as a model protein to study protein soil mineral interactions and gain insights on structural changes and potential degradation of protein. From our simulations, we observe little change to the hydrated Gb1 structure over the kaolinite, montmorillonite, and goethite surfaces relative to its solvated structure without these mineral surfaces present. Over the Na⁺ -birnessite basal surface, however, the Gb1 structure is highly disturbed as a result of interaction with this birnessite surface. Unraveling of the Gb1 β-sheet at specific turns and a partial unraveling of the α-helix is observed over birnessite, which suggests specific vulnerable residue sites for oxidation or hydrolysis possibly leading to fragmentation
Time course analysis of gene expression identifies multiple genes with differential expression in patients with in-stent restenosis
Abstract
Background
The vascular disease in-stent restenosis (ISR) is characterized by formation of neointima and adverse inward remodeling of the artery after injury by coronary stent implantation. We hypothesized that the analysis of gene expression in peripheral blood mononuclear cells (PBMCs) would demonstrate differences in transcript expression between individuals who develop ISR and those who do not.
Methods and Results
We determined and investigated PBMC gene expression of 358 patients undergoing an index procedure to treat in de novo coronary artery lesions with bare metallic stents, using a novel time-varying intercept model to optimally assess the time course of gene expression across a time course of blood samples. Validation analyses were conducted in an independent sample of 97 patients with similar time-course blood sampling and gene expression data. We identified 47 probesets with differential expression, of which 36 were validated upon independent replication testing. The genes identified have varied functions, including some related to cellular growth and metabolism, such as the NAB2 and LAMP genes.
Conclusions
In a study of patients undergoing bare metallic stent implantation, we have identified and replicated differential gene expression in peripheral blood mononuclear cells, studied across a time series of blood samples. The genes identified suggest alterations in cellular growth and metabolism pathways, and these results provide the basis for further specific functional hypothesis generation and testing of the mechanisms of ISR.http://deepblue.lib.umich.edu/bitstream/2027.42/112500/1/12920_2010_Article_214.pd
Microclimatological consequences for plant and microbial composition in Sphagnum-dominated peatlands
In three Scandinavian peatlands we studied to what extent plant and microbial community compositions are governed by local-scale microhabitat, with a special interest in the effect of aspect (i.e. exposition of slopes). Despite differences in solar irradiance between the south- and north-facing slopes, maximum temperature was elevated in the south-facing slopes at the most northern site only. Pore-water nutrient concentrations were not affected by aspect, yet dissolved organic carbon concentrations were higher in the south-facing microhabitats. This was likely caused by higher vascular plant biomass. Plant and microbial community composition clearly differed among sites. In all three sites, microhabitat (i.e. prevailing water-table depth) affected the plant and microbial community compositions. Aspect, however, did not affect community composition, even though microclimate significantly differed between the south- and the north-facing aspects at the northernmost site. Our results highlight the complex link between plant community composition, microbial community and environmental conditions, which deserves much more attention than currently in order to fully understand the effects of climate change on peatland ecosystem function.I
The Effects of Sex-Role Attitudes and Group Composition on Men and Women in Groups
The dual impact of group gender composition and sex-role attitudes on self-perceptions and social behavior was explored. Androgynous and stereotyped men and women were placed in groups of skewed sex composition. Subjects\u27 self-descriptions of masculine attributes shifted significantly in the group environment. In some instances, sex role-stereotyped subjects responded most stereotypically when their gender was in the minority in the group. Differences between men and women and between androgynous and stereotyped subjects in sex role-related preferences for group roles and discussion topics were also found
Metabolic Complementarity and Genomics of the Dual Bacterial Symbiosis of Sharpshooters
Mutualistic intracellular symbiosis between bacteria and insects is a widespread phenomenon that has contributed to the global success of insects. The symbionts, by provisioning nutrients lacking from diets, allow various insects to occupy or dominate ecological niches that might otherwise be unavailable. One such insect is the glassy-winged sharpshooter (Homalodisca coagulata), which feeds on xylem fluid, a diet exceptionally poor in organic nutrients. Phylogenetic studies based on rRNA have shown two types of bacterial symbionts to be coevolving with sharpshooters: the gamma-proteobacterium Baumannia cicadellinicola and the Bacteroidetes species Sulcia muelleri. We report here the sequencing and analysis of the 686,192–base pair genome of B. cicadellinicola and approximately 150 kilobase pairs of the small genome of S. muelleri, both isolated from H. coagulata. Our study, which to our knowledge is the first genomic analysis of an obligate symbiosis involving multiple partners, suggests striking complementarity in the biosynthetic capabilities of the two symbionts: B. cicadellinicola devotes a substantial portion of its genome to the biosynthesis of vitamins and cofactors required by animals and lacks most amino acid biosynthetic pathways, whereas S. muelleri apparently produces most or all of the essential amino acids needed by its host. This finding, along with other results of our genome analysis, suggests the existence of metabolic codependency among the two unrelated endosymbionts and their insect host. This dual symbiosis provides a model case for studying correlated genome evolution and genome reduction involving multiple organisms in an intimate, obligate mutualistic relationship. In addition, our analysis provides insight for the first time into the differences in symbionts between insects (e.g., aphids) that feed on phloem versus those like H. coagulata that feed on xylem. Finally, the genomes of these two symbionts provide potential targets for controlling plant pathogens such as Xylella fastidiosa, a major agroeconomic problem, for which H. coagulata and other sharpshooters serve as vectors of transmission
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