396 research outputs found

    pH-Dependent Capping Interactions Induce Large-Scale Structural Transitions in i-Motifs

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    We study here a DNA oligonucleotide having the ability to form two different i-motif structures whose relative stability depends on pH and temperature. The major species at neutral pH is stabilized by two C:C+ base pairs capped by two minor groove G:C:G:C tetrads. The high pH and thermal stability of this structure are mainly due to the favorable effect of the minor groove tetrads on their adjacent positively charged C:C+ base pairs. At pH 5, we observe a more elongated i-motif structure consisting of four C:C+ base pairs capped by two G:T:G:T tetrads. Molecular dynamics calculations show that the conformational transition between the two structures is driven by the protonation state of key cytosines. In spite of large conformational differences, the transition between the acidic and neutral structures can occur without unfolding of the i-motif. These results represent the first case of a conformational switch between two different i-motif structures and illustrate the dramatic pH-dependent plasticity of this fascinating DNA motif

    Whole genome methylation profiles as independent markers of survival in stage IIIc melanoma patients

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    Background: The clinical course of cutaneous melanoma (CM) can differ significantly for patients with identical stages of disease, defined clinico-pathologically, and no molecular markers differentiate patients with such a diverse prognosis. This study aimed to define the prognostic value of whole genome DNA methylation profiles in stage III CM.Methods: Genome-wide methylation profiles were evaluated by the Illumina Human Methylation 27 BeadChip assay in short-term neoplastic cell cultures from 45 stage IIIC CM patients. Unsupervised K-means partitioning clustering was exploited to sort patients into 2 groups based on their methylation profiles. Methylation patterns related to the discovered groups were determined using the nearest shrunken centroid classification algorithm. The impact of genome-wide methylation patterns on overall survival (OS) was assessed using Cox regression and Kaplan-Meier analyses.Results: Unsupervised K-means partitioning by whole genome methylation profiles identified classes with significantly different OS in stage IIIC CM patients. Patients with a " favorable" methylation profile had increased OS (P = 0.001, log-rank = 10.2) by Kaplan-Meier analysis. Median OS of stage IIIC patients with a " favorable" vs. " unfavorable" methylation profile were 31.5 and 10.4 months, respectively. The 5 year OS for stage IIIC patients with a " favorable" methylation profile was 41.2% as compared to 0% for patients with an " unfavorable" methylation profile. Among the variables examined by multivariate Cox regression analysis, classification defined by methylation profile was the only predictor of OS (Hazard Ratio = 2.41, for " unfavorable" methylation profile; 95% Confidence Interval: 1.02-5.70; P = 0.045). A 17 gene methylation signature able to correctly assign prognosis (overall error rate = 0) in stage IIIC patients on the basis of distinct methylation-defined groups was also identified.Conclusions: A discrete whole-genome methylation signature has been identified as molecular marker of prognosis for stage IIIC CM patients. Its use in daily practice is foreseeable, and promises to refine the comprehensive clinical management of stage III CM patients. © 2012 Sigalotti et al.; licensee BioMed Central Ltd

    Expression and structural features of endoglin (CD105), a transforming growth factor beta1 and beta3 binding protein, in human melanoma.

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    Human endoglin (CD105) is a member of the transforming growth factor beta (TGF-beta) receptor family that binds TGF-beta1 and -beta3, but not TGF-beta2, on human endothelial cells. Immunohistochemical analyses demonstrated that CD105 is expressed on normal and neoplastic cells of the melanocytic lineage. The anti-CD105 MAb, MAEND3, stained 50, 25 and 34% of intradermal naevi, primary and metastatic melanomas investigated, respectively, and nine out of 12 melanoma cell lines. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that CD105 expressed by melanoma cells consists of a homodimeric protein with an apparent molecular weight of 180 and 95 kDa under non-reducing and reducing conditions. Cross-linking of 125I-labelled TGF-beta1 to melanoma cells, Mel 97, by disuccinimidyl suberate (DSS) demonstrated that CD105 expressed on pigmented cells binds TGF-beta1; the pattern of binding of TGF-beta1 to melanoma cells was found to be similar to that of human umbilical vein endothelial cells. The addition of exogenous, bioactive TGF-beta1 significantly (P<0.05) inhibited the growth of CD105-positive melanoma cells, Mel 97, but did not affect that of CD105-negative melanoma cells, F0-1. These data, altogether, demonstrate that CD105 is expressed on pigmented cells and might play a functionally relevant role in the biology of human melanoma cells by regulating their sensitivity to TGF-betas

    Charge Ordering and Ferroelectricity in Half-doped Manganites

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    By means of density-functional simulations for half-doped manganites, such as pseudocubic Pr0.5Ca0.5MnO3 and bilayer PrCa2Mn2O7, we discuss the occurrence of ferroelectricity and we explore its crucial relation to the crystal structure and to peculiar charge/spin/orbital ordering effects. In pseudocubic Pr0.5Ca0.5MnO3, ferroelectricity is induced in the Zener polaron type structure, where Mn ions are dimerized. In marked contrast, in bilayer PrCa2Mn2O7, it is the displacements of apical oxygens bonded to either Mn3+ or Mn4+ ions that play a key role in the rising of ferroelectricity. Importantly, local dipoles due to apical oxygens are also intimately linked to charge and orbital ordering patterns in MnO2 planes, which in turn contribute to polarization. Finally, an important outcome of our work consists in proposing Born effective charges as a valid mean to quantify charge disproportionation effects, in terms of anisotropy and size of electronic clouds around Mn ions.Comment: 5 pages, 2 figures, submitted for publicatio

    Evaluation of the nutritional status of infants from mothers tested positive to HIV/AIDS in the health district of Dschang, Cameroon

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    INTRODUCTION: Poor infant feeding practices are common in Africa, resulting in physical and intellectual developmental impairments. Good feeding practices are crucial, especially in the first year of growth. HIV/AIDS has worsened the clinical and nutritional status of both mothers and their children, exacerbating high rates of malnutrition. The aim of this study was to assess by participative approach, the nutritional status of infants from mothers tested positive to HIV in the health district of Dschang. METHODS: This is a cross sectional study with a period of recruitment of 2 years (2010-2012). Data Collection was done by the aim of a personal slip followed by training to strengthen the nutritional and hygienic capacity of targeted parents. Height and weight of infants were measured and body mass index (BMI) calculated. RESULTS: Significant difference (p ≤ 0.05) was noticed in height-for-age z-score (HAZ) of girls aged between 1 to 2 years compared to 1-year old girls as well as to boys of all ages, defining them as stunted. Furthermore, the weight-for-age z-score (WAZ) results indicate that both girls and boys of all age are in moderate state of malnutrition. The results of BMI thinness classified according to gender and age groups, indicates that most infants (68/130, 52.3%) showed grade 2 thinness predominantly in 2-years old both boys and girls. However, no participants fall within the normal category for age and sex, as well as overweight and obesity categories. CONCLUSION: Undernutrition exists among infants from mothers tested positive to HIV residing in Dschang, as most of the infants are underweight, and malnourished

    Quality of life and satisfaction of patients after oncoplastic or traditional breast-conserving surgery using the BREAST-Q (BCT module): a prospective study

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    Introduction: The oncoplastic conservative surgery was developed as a natural evolution of traditional surgery, attempting to improve the therapeutic and aesthetic outcomes where tumor resection could be followed by not-adequate results. Our primary aim is to evaluate how patient satisfaction and quality-of-life after conservative oncoplastic surgery, using BREAST-Q (BCT Module), change pre- and post-operatively. The secondary aim is to compare patient-reported outcome after oncoplastic or traditional conservative surgery. Patients and methods: We enrolled 647 patients who underwent traditional conservative surgery or oncoplastic surgery from January 2020 to December 2022. Only 232 women (35.9%) completed the BREAST-Q questionnaire on a web-based platform, at the preoperative phase and 3 months after treatment. Results: The average score of "Psychosocial well-being" and "Satisfaction with Breasts" 3 months after surgery showed a statistically significant improvement, while the average score for "Physical well-being: Chest" at 3&nbsp;months showed a worsening compared to the baseline. "Sexual well-being" did not show statistically significant change. A significant difference between the post-operative outcome of oncoplastic surgery and traditional surgery was observed only for Physical well-being (better for traditional surgery). Conclusions: The study showed significant improvement in patient-reported outcomes 3&nbsp;months after the surgery, except for physical discomfort that increases especially after oncoplastic surgery. Furthermore, our data, as well as many others, point to the appropriateness of using OCS where there is an effective indication, while the perspective of patients cannot find significant superiority over TCS in any of the areas analyzed

    Alarming rates of virological failure and HIV-1 drug resistance amongst adolescents living with perinatal HIV in both urban and rural settings: evidence from the EDCTP READY-study in Cameroon

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    Objectives: Adolescents living with perinatal HIV infection (ALPHI) experience persistently high mortality rates, particularly in resource-limited settings. It is therefore clinically important for us to understand the therapeutic response, acquired HIV drug resistance (HIVDR) and associated factors among ALPHI, according to geographical location. Methods: A study was conducted among consenting ALPHI in two urban and two rural health facilities in the Centre Region of Cameroon. World Health Organization (WHO) clinical staging, self-reported adherence, HIVDR early warning indicators (EWIs), immunological status (CD4 count) and plasma viral load (VL) were assessed. For those experiencing virological failure (VF, VL&nbsp;≥&nbsp;1000 copies/mL), HIVDR testing was performed and interpreted using the Stanford HIV Drug Resistance Database v.8.9-1. Results: Of the 270 participants, most were on nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens (61.7% urban vs. 82.2% rural), and about one-third were poorly adherent (30.1% vs. 35.1%). Clinical failure rates (WHO-stage III/IV) in both settings were&nbsp;&lt;&nbsp;15%. In urban settings, the immunological failure (IF) rate (CD4 &nbsp;&lt;&nbsp;250 cells/μL) was 15.8%, statistically associated with late adolescence, female gender and poor adherence. The VF rate was 34.2%, statistically associated with poor adherence and NNRTI-based antiretroviral therapy. In the rural context, the IF rate was 26.9% and the VF rate was 52.7%, both statistically associated with advanced clinical stages. HIVDR rate was over 90% in both settings. EWIs were delayed drug pick-up, drug stock-outs and suboptimal viral suppression. Conclusions: Poor adherence, late adolescent age, female gender and advanced clinical staging worsen IF. The VF rate is high and consistent with the presence of HIVDR in both settings, driven by poor adherence, NNRTI-based regimen and advanced clinical staging

    MicroRNA from moringa oleifera : identification by high throughput sequencing and their potential contribution to plant medicinal value

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    Moringa oleifera is a widespread plant with substantial nutritional and medicinal value. We postulated that microRNAs (miRNAs), which are endogenous, noncoding small RNAs regulating gene expression at the post-Transcriptional level, might contribute to the medicinal properties of plants of this species after ingestion into human body, regulating human gene expression. However, the knowledge is scarce about miRNA in Moringa. Furthermore, in order to test the hypothesis on the pharmacological potential properties of miRNA, we conducted a high-Throughput sequencing analysis using the Illumina platform. A total of 31,290,964 raw reads were produced from a library of small RNA isolated from M. oleifera seeds. We identified 94 conserved and two novel miRNAs that were validated by qRT-PCR assays. Results from qRT-PCR trials conducted on the expression of 20 Moringa miRNA showed that are conserved across multiple plant species as determined by their detection in tissue of other common crop plants. In silico analyses predicted target genes for the conserved miRNA that in turn allowed to relate the miRNAs to the regulation of physiological processes. Some of the predicted plant miRNAs have functional homology to their mammalian counterparts and regulated human genes when they were transfected into cell lines. To our knowledge, this is the first report of discovering M. oleifera miRNAs based on highthroughput sequencing and bioinformatics analysis and we provided new insight into a potential cross-species control of human gene expression. The widespread cultivation and consumption of M. oleifera, for nutritional and medicinal purposes, brings humans into close contact with products and extracts of this plant species. The potential for miRNA transfer should be evaluated as one possible mechanism of action to account for beneficial properties of this valuable species
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