384 research outputs found
Suppressor of cytokine signaling 2 (SOCS2) deletion protects bone health of mice with DSS induced inflammatory bowel disease.
Individuals with inflammatory bowel disease (IBD) often present with poor bone health. The development of targeted therapies for this bone loss requires a fuller understanding of the underlying cellular mechanisms. Although bone loss in IBD is multifactorial the altered sensitivity and secretion of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in IBD is understood to be a critical contributing mechanism. The expression of suppressor of cytokine signaling 2 (SOCS2), a well-established negative regulator of GH signaling, is stimulated by pro-inflammatory cytokines. Therefore, it is likely that SOCS2 expression represents a critical mediator through which pro-inflammatory cytokines inhibit GH/IGF-1 signaling and decrease bone quality in IBD.
Utilising the DSS model of colitis we have revealed that endogenously elevated GH function in the Socs2−/− mouse protects the skeleton from osteopenia. Micro-computed tomography assessment of DSS treated wild-type mice revealed a worsened trabecular architecture compared to control mice. Specifically, DSS treated WT mice had significantly decreased bone volume (BV/TV) (41%; p<0.05), trabecular thickness (16%; p<0.05), trabecular number (30%; p<0.05), and a resulting increase in trabecular separation (19%; <0.05). In comparison, the trabecular bone of Socs2 deficient mice was partially protected from the adverse effects of DSS. The reduction in a number of parameters including BV/TV (21%; p<0.05) was less, and no changes were observed in trabecular thickness or separation. This protected phenotype was unlikely to be a consequence of improved mucosal health in the DSS treated Socs2−/− mice but rather a result of unregulated GH signaling directly on bone.
These studies indicate that the absence of SOCS2 is protective against bone loss typical of IBD. This study also provides an improved understanding of the relative effects of GH/IGF-1 on bone health in experimental colitis, information that is essential before these drugs are explored as bone protective agents in children and adults with IBD
Effect of increasing fruit and vegetable intake by dietary intervention on nutritional biomarkers and attitudes to dietary change : a randomised trial
This work was funded by The Scottish Government Rural and Environmental Science and Analytical Sciences Division (RESAS) and supported by the Rank Prize Funds.Peer reviewedPublisher PD
Pre-treatment HIV-drug resistance associated with virologic outcome of first-line NNRTI-antiretroviral therapy: A cohort study in Kenya
Background: Pre-treatment HIV-drug-resistance (PDR) to WHO-recommended 1st-line non-nucleoside reverse transcriptase inhibitors (NNRTI)-based antiretroviral treatment (ART) is increasing in low-resource communities. We evaluated the risk of PDR on treatment failure if detected at single or multiple codons, at minority (2–9%) or higher (≥10%) frequencies during efavirenz- vs. nevirapine-ART.
Methods: We conducted a pooled analysis across three cohorts of Kenyans initiating 1st-line NNRTI-ART between 2006 and 2014. Mutations K103N, Y181C, G190A, M184V and K65R were detected by an oligonucleotide ligation assay (OLA) and confirmed by Sanger and next-generation sequencing (NGS). PDR was defined as detection of any mutation by OLA when confirmed by NGS. Treatment failure, defined as plasma HIV RNA ≥400 copies/mL at month-12 of ART, was compared by PDR genotypes.
Findings: PDR was detected in 59/1231 (4·8%) participants. Compared to wild-type genotypes, PDR in participants prescribed nevirapine-ART was associated with increased treatment failure [PDR 69·2% (27/39) vs. wild-type 10·4% (70/674); p = 0·0001], whether detected as minority [66·7% (4/6)] or higher [69·7% (23/33)] frequencies in an individual\u27s HIV quasispecies (p = 0·002 and p \u3c 0·0001, respectively), or mutations at single [50·0% (12/24)] or multiple [100·0% (15/15)] codons (p \u3c 0·0001). During efavirenz-ART, PDR was also associated with increased virologic failure [PDR 25·0% (5/20) vs. wild-type 5·0% (25/498); p = 0·005], but only if detected at multiple drug-resistant codons [50·0% (3/6); p = 0·003] or high frequencies PDR [33·3% (5/15); p = 0·001].
Interpretation: The risk that PDR confers for treatment failure varies by number of mutant codons and their frequency in the quasispecies, with a lower risk for efavirenz- compared to nevirapine-based regimens. PDR detection and management could extend the effective use of efavirenz-ART in low-resource settings.
Funding: NIH, PEPFAR
Recommended from our members
Metabolic gatekeeper function of B-lymphoid transcription factors.
B-lymphoid transcription factors, such as PAX5 and IKZF1, are critical for early B-cell development, yet lesions of the genes encoding these transcription factors occur in over 80% of cases of pre-B-cell acute lymphoblastic leukaemia (ALL). The importance of these lesions in ALL has, until now, remained unclear. Here, by combining studies using chromatin immunoprecipitation with sequencing and RNA sequencing, we identify a novel B-lymphoid program for transcriptional repression of glucose and energy supply. Our metabolic analyses revealed that PAX5 and IKZF1 enforce a state of chronic energy deprivation, resulting in constitutive activation of the energy-stress sensor AMPK. Dominant-negative mutants of PAX5 and IKZF1, however, relieved this glucose and energy restriction. In a transgenic pre-B ALL mouse model, the heterozygous deletion of Pax5 increased glucose uptake and ATP levels by more than 25-fold. Reconstitution of PAX5 and IKZF1 in samples from patients with pre-B ALL restored a non-permissive state and induced energy crisis and cell death. A CRISPR/Cas9-based screen of PAX5 and IKZF1 transcriptional targets identified the products of NR3C1 (encoding the glucocorticoid receptor), TXNIP (encoding a glucose-feedback sensor) and CNR2 (encoding a cannabinoid receptor) as central effectors of B-lymphoid restriction of glucose and energy supply. Notably, transport-independent lipophilic methyl-conjugates of pyruvate and tricarboxylic acid cycle metabolites bypassed the gatekeeper function of PAX5 and IKZF1 and readily enabled leukaemic transformation. Conversely, pharmacological TXNIP and CNR2 agonists and a small-molecule AMPK inhibitor strongly synergized with glucocorticoids, identifying TXNIP, CNR2 and AMPK as potential therapeutic targets. Furthermore, our results provide a mechanistic explanation for the empirical finding that glucocorticoids are effective in the treatment of B-lymphoid but not myeloid malignancies. Thus, B-lymphoid transcription factors function as metabolic gatekeepers by limiting the amount of cellular ATP to levels that are insufficient for malignant transformation
Factors Influencing the Participation of Older People in Clinical Trials : Data Analysis from the MAVIS Trial
Peer reviewedPostprin
High birth weight as an important risk factor for infant leukemia
In this paper, we compared the birth weight distribution among 201 infant leukaemia (IL) cases with that of 440 noncancer controls enrolled in Brazil in 1999–2005. Compared with the general population and the stratum 2500–2999 g as reference, IL cases weighing 3000–3999 g presented an odds ratio (OR) of 1.68 (95% CI: 1.03–2.76), and those of 4000 g or more, an OR of 2.28 (95% CI: 1.08–4.75), Ptrend<0.01. Using hospital-based controls, the OR for 4000 g or more, compared to 2500–2999 g, was 1.30 (95% CI: 1.02–1.43) after adjusting for confounders (gender, income, maternal age, pesticide and hormonal exposure during pregnancy). The results suggest that high birth weight is associated with increased risk of IL
Tightening the pores to unload the phloem
Root growth depends on the shoot-to-root transport of assimilates through the phloem, which is connected to the meristems by plasmodesmata pores. A PHLOEM UNLOADING MODULATOR is now identified to regulate plasmodesmata internal organisation, leading to pores that appear tighter but are more efficient for transport
In search of phylogenetic congruence between molecular and morphological data in bryozoans with extreme adult skeletal heteromorphy
peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=tsab20© Crown Copyright 2015. This document is the author's final accepted/submitted version of the journal article. You are advised to consult the publisher's version if you wish to cite from it
Individually customisable non-invasive head immobilisation system for non-human primates with an option for voluntary engagement
Background:
Head immobilisation is often necessary for neuroscientific procedures. A number of Non-invasive Head Immobilisation Systems (NHIS) for monkeys are available, but the need remains for a feasible integrated system combining a broad range of essential features.
New method:
We developed an individualised macaque NHIS addressing several animal welfare and scientific needs. The system comprises a customised-to-fit facemask that can be used separately or combined with a back piece to form a full-head helmet. The system permits presentation of visual and auditory stimuli during immobilisation and provides mouth access for reward.
Results:
The facemask was incorporated into an automated voluntary training system, allowing the animals to engage with it for increasing periods leading to full head immobilisation. We evaluated the system during performance on several auditory or visual behavioural tasks with testing sessions lasting 1.5–2 h, used thermal imaging to monitor for and prevent pressure points, and measured head movement using MRI.
Comparison with existing methods:
A comprehensive evaluation of the system is provided in relation to several scientific and animal welfare requirements. Behavioural results were often comparable to those obtained with surgical implants. Cost–benefit analyses were conducted comparing the system with surgical options, highlighting the benefits of implementing the non-invasive option.
Conclusions:
The system has a number of potential applications and could be an important tool in neuroscientific research, when direct access to the brain for neuronal recordings is not required, offering the opportunity to conduct non-invasive experiments while improving animal welfare and reducing reliance on surgically implanted head posts
Incomplete Diversification and Asset Pricing
Investors in equilibrium are modeled as facing investor specific risks across the space of assets. Personalized asset pricing models reflect these risks. Averaging across the pool of investors we obtain a market asset pricing model that reflects market risk exposures. It is observed on invoking a law of large numbers applied to an infinite population of investors, that many personally relevant risk considerations can be eliminated from the market asset pricing model. Examples illustrating the effects of undiversified labor income and taste specific price indices are provided. Suggestions for future work on asset pricing include a need to focus on identifying and explaining investor specific risk exposures
- …