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  • 11
    Publication Date: 2012-02-28
    Description: Histone post-translational modifications play an important role in regulating chromatin structure and gene expression in vivo . Extensive studies investigated the post-translational modifications of the core histones H3 and H4 or the linker histone H1. Much less is known on the regulation of H2A and H2B modifications. Here, we show that a major modification of H2B in Drosophila melanogaster is the methylation of the N-terminal proline, which increases during fly development. Experiments performed in cultured cells revealed higher levels of H2B methylation when cells are dense, regardless of their cell cycle distribution. We identified dNTMT (CG1675) as the enzyme responsible for H2B methylation. We also found that the level of N-terminal methylation is regulated by dART8, an arginine methyltransferase that physically interacts with dNTMT and asymmetrically methylates H3R2. Our results demonstrate the existence of a complex containing two methyltransferases enzymes, which negatively influence each other’s activity.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 12
    Publication Date: 2011-09-29
    Description: SUMMARY We propose a class of spherical wavelet bases for the analysis of geophysical models and for the tomographic inversion of global seismic data. Its multiresolution character allows for modelling with an effective spatial resolution that varies with position within the Earth. Our procedure is numerically efficient and can be implemented with parallel computing. We discuss two possible types of discrete wavelet transforms in the angular dimension of the cubed sphere. We describe benefits and drawbacks of these constructions and apply them to analyse the information in two published seismic wave speed models of the mantle, using the statistics of wavelet coefficients across scales. The localization and sparsity properties of wavelet bases allow finding a sparse solution to inverse problems by iterative minimization of a combination of the ℓ 2 norm of the data residuals and the ℓ 1 norm of the model wavelet coefficients. By validation with realistic synthetic experiments we illustrate the likely gains from our new approach in future inversions of finite-frequency seismic data.
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 13
    Publication Date: 2012-05-16
    Description: Much is known about the evolution of plant immunity components directed against specific pathogen strains: They show pervasive functional variation and have the potential to coevolve with pathogen populations. However, plants are effectively protected against most microbes by generalist immunity components that detect conserved pathogen-associated molecular patterns (PAMPs) and control the onset of PAMP-triggered immunity. In Arabidopsis thaliana , the receptor kinase flagellin sensing 2 (FLS2) confers recognition of bacterial flagellin (flg22) and activates a manifold defense response. To decipher the evolution of this system, we performed functional assays across a large set of A. thaliana genotypes and Brassicaceae relatives. We reveal extensive variation in flg22 perception, most of which results from changes in protein abundance. The observed variation correlates with both the severity of elicited defense responses and bacterial proliferation. We analyzed nucleotide variation segregating at FLS2 in A. thaliana and detected a pattern of variation suggestive of the rapid fixation of a novel adaptive allele. However, our study also shows that evolution at the receptor locus alone does not explain the evolution of flagellin perception; instead, components common to pathways downstream of PAMP perception likely contribute to the observed quantitative variation. Within and among close relatives, PAMP perception evolves quantitatively, which contrasts with the changes in recognition typically associated with the evolution of R genes.
    Print ISSN: 0737-4038
    Electronic ISSN: 1537-1719
    Topics: Biology
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  • 14
    Publication Date: 2012-06-12
    Description: In response to gonadectomy certain inbred mouse strains develop sex steroidogenic adrenocortical neoplasms. One of the hallmarks of neoplastic transformation is expression of GATA4, a transcription factor normally present in gonadal but not adrenal steroidogenic cells of the adult mouse. To show that GATA4 directly modulates adrenocortical tumorigenesis and is not merely a marker of gonadal-like differentiation in the neoplasms, we studied mice with germline or conditional loss-of-function mutations in the Gata4 gene. Germline Gata4 haploinsufficiency was associated with attenuated tumor growth and reduced expression of sex steroidogenic genes in the adrenal glands of ovariectomized B6D2F1 and B6AF1 mice. At 12 months after ovariectomy, wild-type B6D2F1 mice had biochemical and histological evidence of adrenocortical estrogen production, whereas Gata4 +/– B6D2F1 mice did not. Germline Gata4 haploinsufficiency exacerbated the secondary phenotype of postovariectomy obesity in B6D2F1 mice, presumably by limiting ectopic estrogen production in the adrenal glands. Amhr2 -cre-mediated deletion of floxed Gata4 ( Gata4 F ) in nascent adrenocortical neoplasms of ovariectomized B6.129 mice reduced tumor growth and the expression of gonadal-like markers in a Gata4 F dose-dependent manner. We conclude that GATA4 is a key modifier of gonadectomy-induced adrenocortical neoplasia, postovariectomy obesity, and sex steroidogenic cell differentiation.
    Print ISSN: 0013-7227
    Topics: Medicine
    Published by Oxford University Press on behalf of The Endocrine Society.
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  • 15
    Publication Date: 2013-01-23
    Description: We evaluated the impact of staging procedures to detect asymptomatic distant metastases (DM) in the management of women with operable invasive breast cancer (BC, entire cohort: n = 866). Out of 472 patients with lymph node (LN)-negative disease (pN0), DM were found in four cases (detection rate: 0.8%). All four patients presented with established risk factors: hormone receptor (HR)-negative status, HER2-positive status, n = 3; ‘triple-negative’ disease, n = 1. Considering the subgroup of LN-negative patients whose tumors showed the risk factor ‘negative HR status’ ( n = 66), the detection rate of DM was 6%. The detection rates of DM in higher pN categories were as follows: pN1:1.7%; pN2:9.5%; pN3:13.5%. We generally support the international guidelines, including those published by the European Society for Medical Oncology (ESMO) which emphasize that patients with early-stage BC do not profit from radiological staging for the detection of DM and recommend refraining from this. However, we would expand these guidelines and propose that screening should be carried out in node-negative patients whose tumors show established tumor-related risk factors (e.g. HR-negative and HER2-positive status), since in this particular subcohort, the detection rate of DM is with 6% similarly high as that of patients with four to nine positive LNs.
    Print ISSN: 0923-7534
    Electronic ISSN: 1569-8041
    Topics: Medicine
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  • 16
    Publication Date: 2013-03-16
    Description: Background: Varied and fragmented care plans undertaken by different practitioners currently expose surgical patients to lapses in expected care, increase the chance for operational mistakes and accidents, and often result in unnecessary care. The Perioperative Surgical Home has thus been proposed by the American Society of Anesthesiologists and other stakeholders as an innovative, patient-centered, surgical continuity of care model that incorporates shared decision making. Topics central to the debate about an anesthesiology-based Perioperative Surgical Home include: holding the gains made in anesthesia-related patient safety; impacting surgical morbidity and mortality, including failure-to-rescue; achieving healthcare outcome metrics; assimilating comparative effectiveness research into the model; establishing necessary audit and data collection; a comparison with the hospitalist model of perioperative care; the perspective of the surgeon; the benefits of the Perioperative Surgical Home to the specialty of anesthesiology; and its associated healthcare economic advantages.DiscussionImproving surgical morbidity and mortality mandates a more comprehensive and integrated approach to the management of surgical patients. In their expanded capacity as the surgical patient's "perioperativist," anesthesiologists can play a key role in compliance with broader set of process measures, thus becoming a more vital and valuable provider from the patient, administrator, and payer perspective. The robust perioperative databases created within the Perioperative Surgical Home present new opportunities for health services and population-level research. The Perioperative Surgical Home is not intended to replace the surgeon's patient care responsibility, but rather leverage the abilities of the entire perioperative care team in the service of the patient. To achieve this goal, it will be necessary to expand the core knowledge, skills, and experience of anesthesiologists. Anesthesiologists will need to view becoming perioperative physicians as an expansion of the specialty, rather than an abdication of their traditional intraoperative role. The Perioperative Surgical Home will need to create strategic added value for a health system and payers. This added value will strengthen the position of anesthesiologists as they navigate and negotiate in the face of finite, if not decreasing fiscal resources.SummaryBroadening the anesthesiologist's scope of practice via the Perioperative Surgical Home may promote standardization and improve clinical outcomes and decrease resource utilization by providing greater patient-centered continuity of care throughout the preoperative, intraoperative, and postoperative periods.
    Electronic ISSN: 1471-2253
    Topics: Medicine
    Published by BioMed Central
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  • 17
    Publication Date: 2014-09-17
    Description: Background Peripheral neuropathy is the major dose-limiting side effect of cisplatin and oxaliplatin, and there are currently no effective treatments available. The aim of this study was to assess the pharmacological mechanisms underlying chemotherapy-induced neuropathy in novel animal models based on intraplantar administration of cisplatin and oxaliplatin and to systematically evaluate the analgesic efficacy of a range of therapeutics. Methods Neuropathy was induced by a single intraplantar injection of cisplatin or oxaliplatin in C57BL/6J mice and assessed by quantification of mechanical and thermal allodynia. The pharmacological basis of cisplatin-induced neuropathy was characterized using a range of selective pharmacological inhibitors. The analgesic effects of phenytoin, amitriptyline, oxcarbazepine, mexiletine, topiramate, retigabine, gabapentin, fentanyl, and Ca 2+/ Mg 2+ were assessed 24 hours after induction of neuropathy. Results Intraplantar administration of cisplatin led to the development of mechanical allodynia, mediated through Na v 1.6-expressing sensory neurons. Unlike intraplantar injection of oxaliplatin, cold allodynia was not observed with cisplatin, consistent with clinical observations. Surprisingly, only fentanyl was effective at alleviating cisplatin-induced mechanical allodynia despite a lack of efficacy in oxaliplatin-induced cold allodynia. Conversely, lamotrigine, phenytoin, retigabine, and gabapentin were effective at reversing oxaliplatin-induced cold allodynia but had no effect on cisplatin-induced mechanical allodynia. Oxcarbazepine, amitriptyline, mexiletine, and topiramate lacked efficacy in both models of acute chemotherapy-induced neuropathy. Conclusion This study established a novel animal model of cisplatin-induced mechanical allodynia consistent with the A-fiber neuropathy seen clinically. Systematic assessment of a range of therapeutics identified several candidates that warrant further clinical investigation.
    Print ISSN: 1522-8517
    Electronic ISSN: 1523-5866
    Topics: Medicine
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  • 18
    Publication Date: 2014-11-30
    Description: Background: In contrast with breast cancers (BCs) in other parts of the world, most previous studies reported that the majority of BCs in sub-Saharan Africa are estrogen-receptor (ER) negative. However, a recent study using the US SEER database showed that the proportion of ER-negative BC is comparable between US-born blacks and West-African born blacks but substantially lower in East African-born blacks, with over 74% of patients Ethiopians or Eritreans. In this paper, we provide the first report on the proportion of ER-negative BC in Ethiopia, and the relation to progesterone-receptor (PgR) status. Methods: We analysed 352 female patients with ER results available out of 1208 consecutive female BC patients treated at Addis Ababa-University Hospital, Ethiopia, from June 2005 through December 2010. The influences of age, stage, and histology on the probability of ER-negative tumours were assessed by a log-linear regression model. Results: Of the 352 patients, only 35% were ER negative. The proportion of ER-negative tumours decreased with advancing age at diagnosis and was not affected by histology or stage. For age, the proportion decreased by 6% for each additional 5 years (stage-adjusted prevalence ratio PR = 0.94, 95% CI: 0.89-1.00). About 31% were ER- and PgR-negative, and 69% were ER- and/or PgR-positive. Conclusions: Contrary to most previous reports in other parts of sub-Saharan Africa, the majority of patients in Ethiopia are ER positive rather than ER negative. These findings are in line with low proportions of ER-negative BCs from East African immigrants within the SEER database, and they have clinical implications for management of BC patients in Ethiopia and other parts of sub-Saharan Africa where ER-status is not ascertained as part of routine management of the disease. Since the majority of patients showed ER-positive BC, Tamoxifen-therapy should be given to all patients even with unknown ER-status.
    Electronic ISSN: 1471-2407
    Topics: Medicine
    Published by BioMed Central
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  • 19
    Publication Date: 2015-03-09
    Description: Background: The relationship between psychological stress and interstitial cystitis/bladder pain syndrome (IC/BPS) has been well described. Even though there is some overlapping of symptoms between overactive bladder (OAB) and IC/BPS, there have been very few studies that specifically investigated the relationship between psychological stress and urinary symptoms in OAB patients who do not have pelvic pain. Here we examined the relationship between psychological stress levels and the severity of overactive bladder (OAB) symptoms. Methods: Patients diagnosed with OAB (n=51), IC/BPS (n=27), and age-matched healthy controls (n=30) participated in a case control study that inquired about their psychological stress levels using the perceived stress scale (PSS). PSS reported by the three patient groups were compared. Among OAB patients, their responses on the PSS was correlated to OAB symptoms using the following questionnaires: 1) international consultation on incontinence – urinary incontinence (ICIQ-UI), 2) international consultation on incontinence – overactive bladder (ICIQ-OAB), 3) OAB-q short form, 4) urogenital distress inventory (UDI-6), 5) incontinence impact questionnaire (IIQ-7), 6) urgency severity scale (USS), 7) numeric rating scales of urgency symptom, and 8) frequency symptom. Spearman’s correlation tests were performed to examine the relationship between psychological stress levels and the severity of OAB symptoms. Results: OAB patients reported psychological stress levels that were as high as IC/BPS patients (median 17.0 versus 18.0, p=0.818, Wilcoxon sum rank test), and significantly higher than healthy controls (17.0, versus 7.5, p=0.001). Among OAB patients, there was a positive correlation between perceived stress levels and urinary incontinence symptoms (ICIQ-UI, Spearman’s correlation coefficient=0.39, p=0.007), and impacts on quality of life (UDI-6, IIQ-7, OAB-q quality of life subscale; Spearman’s correlation coefficient=0.32, 0.31, 0.39, and p=0.028, 0.005, 0.029, respectively). No significant correlation was observed between perceived stress levels and urgency or frequency symptoms (ICIQ-OAB, USS, numeric ratings of urgency and frequency). Conclusions: OAB patients reported psychological stress levels that were as high as IC/BPS patients, and significantly higher than healthy controls. There was a positive correlation between perceived stress levels and urinary incontinence symptoms, and its impacts on quality of life among OAB patients.
    Electronic ISSN: 1471-2490
    Topics: Medicine
    Published by BioMed Central
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  • 20
    Publication Date: 2015-07-31
    Description: Background: Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most common disorder of mitochondrial fatty acid β-oxidation and a target disease of newborn screening in many countries.Case presentationWe report on two siblings with mild MCAD deficiency associated with a novel splice site mutation in the ACADM gene. The younger sibling was detected by newborn screening, while the older sister was missed, but diagnosed later on by genetic family testing. Both children were found to be compound heterozygous for the common c.985A 〉 G (p.K329E) mutation and a novel splice site mutation, c.600-18G 〉 A, in the ACADM gene. To determine the biological consequence of the c.600-18G 〉 A mutation putative missplicing was investigated at RNA level in granulocytes and monocytes of one of the patients. The splice site mutation was shown to lead to partial missplicing of the ACADM pre-mRNA. Of three detected transcripts two result in truncated, non-functional MCAD proteins as reflected by the reduced octanoyl-CoA oxidation rate in both patients. In one patient a decrease of the octanoyl-CoA oxidation rate was found during a febrile infection indicating that missplicing may be temperature-sensitive. Conclusions: Our data indicate that the c.600-18G 〉 A variant activates a cryptic splice site, which competes with the natural splice site. Due to only partial missplicing sufficient functional MCAD protein remains to result in mild MCADD that may be missed by newborn screening.
    Electronic ISSN: 1471-2350
    Topics: Biology , Medicine
    Published by BioMed Central
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