112 research outputs found

    Synthetic Heparan Sulfate Oligosaccharides Inhibit Endothelial Cell Functions Essential for Angiogenesis

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    Heparan sulfate (HS) is an important regulator of the assembly and activity of various angiogenic signalling complexes. However, the significance of precisely defined HS structures in regulating cytokine-dependent angiogenic cellular functions and signalling through receptors regulating angiogenic responses remains unclear. Understanding such structure-activity relationships is important for the rational design of HS fragments that inhibit HS-dependent angiogenic signalling complexes.We synthesized a series of HS oligosaccharides ranging from 7 to 12 saccharide residues that contained a repeating disaccharide unit consisting of iduronate 2-O-sulfate linked to glucosamine with or without N-sulfate. The ability of oligosaccharides to compete with HS for FGF2 and VEGF165 binding significantly increased with oligosaccharide length and sulfation. Correspondingly, the inhibitory potential of oligosaccharides against FGF2- and VEGF165-induced endothelial cell responses was greater in longer oligosaccharide species that were comprised of disaccharides bearing both 2-O- and N-sulfation (2SNS). FGF2- and VEGF165-induced endothelial cell migration were inhibited by longer 2SNS oligosaccharide species with 2SNS dodecasaccharide activity being comparable to that of receptor tyrosine kinase inhibitors targeting FGFR or VEGFR-2. Moreover, the 2SNS dodecasaccharide ablated FGF2- or VEGF165-induced phosphorylation of FAK and assembly of F-actin in peripheral lamellipodia-like structures. In contrast, FGF2-induced endothelial cell proliferation was only moderately inhibited by longer 2SNS oligosaccharides. Inhibition of FGF2- and VEGF165-dependent endothelial tube formation strongly correlated with oligosaccharide length and sulfation with 10-mer and 12-mer 2SNS oligosaccharides being the most potent species. FGF2- and VEGF165-induced activation of MAPK pathway was inhibited by biologically active oligosaccharides correlating with the specific phosphorylation events in FRS2 and VEGFR-2, respectively.These results demonstrate structure-function relationships for synthetic HS saccharides that suppress endothelial cell migration, tube formation and signalling induced by key angiogenic cytokines

    Traumatic bone cyst of the mandible of possible iatrogenic origin: a case report and brief review of the literature

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    The traumatic bone cyst (TBC) is an uncommon nonepithelial lined cavity of the jaws. The lesion is mainly diagnosed in young patients most frequently during the second decade of life. The majority of TBCs are located in the mandibular body between the canine and the third molar. Clinically, the lesion is asymptomatic in the majority of cases and is often accidentally discovered on routine radiological examination usually as an unilocular radiolucent area with a "scalloping effect". The definite diagnosis of traumatic cyst is invariably achieved at surgery. Since material for histologic examination may be scant or non-existent, it is very often difficult for a definite histologic diagnosis to be achieved. We present a well documented radiographically and histopathologically atypical case of TBC involving the ramus of the mandible, which is also of possible iatrogenic origin. The literature is briefly reviewed

    Epigenetic reprogramming of breast cancer cells with oocyte extracts

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    <p>Abstract</p> <p>Background</p> <p>Breast cancer is a disease characterised by both genetic and epigenetic alterations. Epigenetic silencing of tumour suppressor genes is an early event in breast carcinogenesis and reversion of gene silencing by epigenetic reprogramming can provide clues to the mechanisms responsible for tumour initiation and progression. In this study we apply the reprogramming capacity of oocytes to cancer cells in order to study breast oncogenesis.</p> <p>Results</p> <p>We show that breast cancer cells can be directly reprogrammed by amphibian oocyte extracts. The reprogramming effect, after six hours of treatment, in the absence of DNA replication, includes DNA demethylation and removal of repressive histone marks at the promoters of tumour suppressor genes; also, expression of the silenced genes is re-activated in response to treatment. This activity is specific to oocytes as it is not elicited by extracts from ovulated eggs, and is present at very limited levels in extracts from mouse embryonic stem cells. Epigenetic reprogramming in oocyte extracts results in reduction of cancer cell growth under anchorage independent conditions and a reduction in tumour growth in mouse xenografts.</p> <p>Conclusions</p> <p>This study presents a new method to investigate tumour reversion by epigenetic reprogramming. After testing extracts from different sources, we found that axolotl oocyte extracts possess superior reprogramming ability, which reverses epigenetic silencing of tumour suppressor genes and tumorigenicity of breast cancer cells in a mouse xenograft model. Therefore this system can be extremely valuable for dissecting the mechanisms involved in tumour suppressor gene silencing and identifying molecular activities capable of arresting tumour growth. These applications can ultimately shed light on the contribution of epigenetic alterations in breast cancer and advance the development of epigenetic therapies.</p

    Testicular Dysgenesis Syndrome and the Estrogen Hypothesis: A Quantitative Meta-Analysis

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    BACKGROUND: Male reproductive tract abnormalities such as hypospadias and cryptorchidism, and testicular cancer have been proposed to comprise a common syndrome together with impaired spermatogenesis with a common etiology resulting from the disruption of gonadal development during fetal life, the testicular dysgenesis syndrome (TDS). The hypothesis that in utero exposure to estrogenic agents could induce these disorders was first proposed in 1993. The only quantitative summary estimate of the association between prenatal exposure to estrogenic agents and testicular cancer was published over 10 years ago, and other systematic reviews of the association between estrogenic compounds, other than the potent pharmaceutical estrogen diethylstilbestrol (DES), and TDS end points have remained inconclusive. OBJECTIVES: We conducted a quantitative meta-analysis of the association between the end points related to TDS and prenatal exposure to estrogenic agents. Inclusion in this analysis was based on mechanistic criteria, and the plausibility of an estrogen receptor (ER)-–mediated mode of action was specifically explored. RESULTS: We included in this meta-analysis eight studies investigating the etiology of hypospadias and/or cryptorchidism that had not been identified in previous systematic reviews. Four additional studies of pharmaceutical estrogens yielded a statistically significant updated summary estimate for testicular cancer. CONCLUSIONS: The doubling of the risk ratios for all three end points investigated after DES exposure is consistent with a shared etiology and the TDS hypothesis but does not constitute evidence of an estrogenic mode of action. Results of the subset analyses point to the existence of unidentified sources of heterogeneity between studies or within the study population

    Applying the ALARA concept to the evaluation of vesicoureteric reflux

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    The voiding cystourethrogram (VCUG) is a widely used study to define lower urinary tract anatomy and to diagnose vesicoureteric reflux (VUR) in children. We examine the technical advances in the VCUG and other examinations for reflux that have reduced radiation exposure of children, and we give recommendations for the use of imaging studies in four groups of children: (1) children with urinary tract infection, (2) siblings of patients with VUR, (3) infants with antenatal hydronephrosis (ANH), and (4) children with a solitary functioning kidney. By performing examinations with little to no radiation, carefully selecting only the children who need imaging studies and judiciously timing follow-up examinations, we can reduce the radiation exposure of children being studied for reflux

    Physiotherapy Post Lumbar Discectomy: Prospective Feasibility and Pilot Randomised Controlled Trial

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    Objectives To evaluate: acceptability and feasibility of trial procedures; distribution of scores on the Roland Morris Disability Questionnaire (RMDQ, planned primary outcome); and efficient working of trial components. Design and Setting A feasibility and external pilot randomised controlled trial (ISRCTN33808269, assigned 10/12/2012) was conducted across 2 UK secondary care outpatient physiotherapy departments associated with regional spinal surgery centres. Participants Consecutive consenting patients aged >18 years; post primary, single level, lumbar discectomy. Interventions Participants were randomised to either 1:1 physiotherapy outpatient management including patient leaflet, or patient leaflet alone. Main Outcome Measures Blinded assessments were made at 4 weeks post surgery (baseline) and 12 weeks post baseline (proposed primary end point). Secondary outcomes included: Global Perceived Effect, back/leg pain, straight leg raise, return to work/function, quality of life, fear avoidance, range of movement, medication, re-operation. Results At discharge, 110 (44%) eligible patients gave consent to be contacted. 59 (54%) patients were recruited. Loss to follow up was 39% at 12 weeks, with one site contributing 83% losses. Mean (SD) RMDQ was 10.07 (5.58) leaflet and 10.52 (5.94) physiotherapy/leaflet at baseline; and 5.37 (4.91) leaflet and 5.53 (4.49) physiotherapy/leaflet at 12 weeks. 5.1% zero scores at 12 weeks illustrated no floor effect. Sensitivity to change was assessed at 12 weeks with mean (SD) change -4.53 (6.41), 95%CI -7.61 to -1.44 for leaflet; and -6.18 (5.59), 95%CI -9.01 to -3.30 for physiotherapy/leaflet. RMDQ mean difference (95%CI) between change from baseline to twelve weeks was 1.65(-2.46 to 5.75). Mean difference (95%CI) between groups at 12 weeks was -0.16 (-3.36 to 3.04). Participant adherence with treatment was good. No adverse events were reported. Conclusions Both interventions were acceptable, and it is promising that they both demonstrated a trend in reducing disability in this population. A randomised controlled trial, using a different trial design, is needed to ascertain the effectiveness of combining the interventions into a stepped care intervention and comparing to a no intervention arm. Findings will guide design changes for an adequately powered randomised controlled trial, using RMDQ as the primary outcome

    A 'snip' in time: what is the best age to circumcise?

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    <p>Abstract</p> <p>Background</p> <p>Circumcision is a common procedure, but regional and societal attitudes differ on whether there is a need for a male to be circumcised and, if so, at what age. This is an important issue for many parents, but also pediatricians, other doctors, policy makers, public health authorities, medical bodies, and males themselves.</p> <p>Discussion</p> <p>We show here that infancy is an optimal time for clinical circumcision because an infant's low mobility facilitates the use of local anesthesia, sutures are not required, healing is quick, cosmetic outcome is usually excellent, costs are minimal, and complications are uncommon. The benefits of infant circumcision include prevention of urinary tract infections (a cause of renal scarring), reduction in risk of inflammatory foreskin conditions such as balanoposthitis, foreskin injuries, phimosis and paraphimosis. When the boy later becomes sexually active he has substantial protection against risk of HIV and other viral sexually transmitted infections such as genital herpes and oncogenic human papillomavirus, as well as penile cancer. The risk of cervical cancer in his female partner(s) is also reduced. Circumcision in adolescence or adulthood may evoke a fear of pain, penile damage or reduced sexual pleasure, even though unfounded. Time off work or school will be needed, cost is much greater, as are risks of complications, healing is slower, and stitches or tissue glue must be used.</p> <p>Summary</p> <p>Infant circumcision is safe, simple, convenient and cost-effective. The available evidence strongly supports infancy as the optimal time for circumcision.</p

    Art in corporate governance: A Deweyan perspective on board experience

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    Corporate governance sits at the intersection of many aspects of disciplines from business, management, finance and accounting. The point of departure for the overwhelming portion of studies concerns the ugliness of greed, ambition, misdemeanors and malfeasance of corporations, their directors, and those actors hold own shares in them. This essay takes a rather different starting point. Drawing upon insights from a radically different field, it uses the discussion of aesthetics in Dewey’s treatise on art (1934/1958) to ask what motivates directors to act in ways that constitute the attention and engagement that we associate with the effectiveness of boards. Using Dewey’s thinking about aesthetic experience, this paper compares it with accounts of the experience of corporate boards, both in the literature and in the personal experience of the author. These observations point to need to reflect on motivation when considering both the practice of corporate governance and the policy frameworks in which it operates
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