98 research outputs found

    Footprints of Inversions at Present and Past Pseudoautosomal Boundaries in Human Sex Chromosomes

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    The human sex chromosomes have stopped recombining gradually, which has left five evolutionary strata on the X chromosome. Y inversions are thought to have suppressed X–Y recombination but clear evidence is missing. Here, we looked for such evidence by focusing on a region—the X-added region (XAR)—that includes the pseudoautosomal region and the most recent strata 3 to 5. We estimated and analyzed the whole set of parsimonious scenarios of Y inversions given the gene order in XAR and its Y homolog. Comparing these to scenarios for simulated sequences suggests that the strata 4 and 5 were formed by Y inversions. By comparing the X and Y DNA sequences, we found clear evidence of two Y inversions associated with duplications that coincide with the boundaries of strata 4 and 5. Divergence between duplicates is in agreement with the timing of strata 4 and 5 formation. These duplicates show a complex pattern of gene conversion that resembles the pattern previously found for AMELXY, a stratum 3 locus. This suggests that this locus—despite AMELY being unbroken—was possibly involved in a Y inversion that formed stratum 3. However, no clear evidence supporting the formation of stratum 3 by a Y inversion was found, probably because this stratum is too old for such an inversion to be detectable. Our results strongly support the view that the most recent human strata have arisen by Y inversions and suggest that inversions have played a major role in the differentiation of our sex chromosomes

    Wound contraction effects and antibacterial properties of Tualang honey on full-thickness burn wounds in rats in comparison to hydrofibre

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    <p>Abstract</p> <p>Background</p> <p>Full-thickness burn wounds require excision and skin grafting. Multiple surgical procedures are inevitable in managing moderate to severe full-thickness burns. Wound bed preparations prior to surgery are necessary in order to prevent wound infection and promote wound healing. Honey can be used to treat burn wounds. However, not all the honey is the same. This study aims to evaluate the wound contraction and antibacterial properties of locally-produced <it>Tualang </it>honey on managing full-thickness burn wounds <it>in vivo</it>.</p> <p>Methods</p> <p>Thirty-six female <it>Sprague Dawley </it>rats were randomly divided into three groups. Under anaesthesia, three full-thickness burn wounds were created on the dorsum of the rats. The full-thickness burn wounds were inoculated with a specific organism (10<sup>4</sup>), namely <it>Pseudomonas aeruginosa </it>(n = 12), <it>Klebsiella pneumoniae </it>(n = 12), or <it>Acinetobacter baumannii </it>(n = 12). The three burn wounds were dressed with <it>Tualang </it>honey, hydrofibre and hydrofibre silver respectively. Swab samples were obtained every 3 days (day 3, 6, 9, 12, 15, 18 and 21) for quantitative and semi-quantitative microbiological analyses. Clinical assessments, including observations concerning the appearance and wound size, were measured at the same time.</p> <p>Results</p> <p>There was a rapid 32.26% reduction in wound size by day 6 (<it>p </it>= 0.008) in the <it>Tualang </it>honey-treated wounds, and 49.27% by day 15 (<it>p </it>= 0.005). The wounds remained smaller by day 18 (<it>p </it>< 0.032). <it>Tualang </it>honey-treated rats demonstrated a reduction in bacterial growth in <it>Pseudomonas aeruginosa </it>inoculated wounds (<it>p </it>= 0.005). However, hydrofibre silver and hydrofibre-treated wounds are superior to honey-treated wounds with <it>Acinetobacter baumannii </it>(<it>p </it>= 0.035). There was no statistical significant of antibacterial property in <it>Klebsiella pneumonia </it>inoculated wounds.</p> <p>Conclusions</p> <p><it>Tualang </it>honey has better results with regards to its control of <it>Pseudomonas aeruginosa </it>and its wound contraction effects on full-thickness burn wound <it>in vivo</it>.</p

    Recombination Drives Vertebrate Genome Contraction

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    Selective and/or neutral processes may govern variation in DNA content and, ultimately, genome size. The observation in several organisms of a negative correlation between recombination rate and intron size could be compatible with a neutral model in which recombination is mutagenic for length changes. We used whole-genome data on small insertions and deletions within transposable elements from chicken and zebra finch to demonstrate clear links between recombination rate and a number of attributes of reduced DNA content. Recombination rate was negatively correlated with the length of introns, transposable elements, and intergenic spacer and with the rate of short insertions. Importantly, it was positively correlated with gene density, the rate of short deletions, the deletion bias, and the net change in sequence length. All these observations point at a pattern of more condensed genome structure in regions of high recombination. Based on the observed rates of small insertions and deletions and assuming that these rates are representative for the whole genome, we estimate that the genome of the most recent common ancestor of birds and lizards has lost nearly 20% of its DNA content up until the present. Expansion of transposable elements can counteract the effect of deletions in an equilibrium mutation model; however, since the activity of transposable elements has been low in the avian lineage, the deletion bias is likely to have had a significant effect on genome size evolution in dinosaurs and birds, contributing to the maintenance of a small genome. We also demonstrate that most of the observed correlations between recombination rate and genome contraction parameters are seen in the human genome, including for segregating indel polymorphisms. Our data are compatible with a neutral model in which recombination drives vertebrate genome size evolution and gives no direct support for a role of natural selection in this process

    BRF1 accelerates prostate tumourigenesis and perturbs immune infiltration

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    BRF1 is a rate-limiting factor for RNA Polymerase III-mediated transcription and is elevated in numerous cancers. Here, we report that elevated levels of BRF1 associate with poor prognosis in human prostate cancer. In vitro studies in human prostate cancer cell lines demonstrated that transient overexpression of BRF1 increased cell proliferation whereas the transient downregulation of BRF1 reduced proliferation and mediated cell cycle arrest. Consistent with our clinical observations, BRF1 overexpression in a Pten-deficient mouse (Pten BRF1 ) prostate cancer model accelerated prostate carcinogenesis and shortened survival. In Pten BRF1 tumours, immune and inflammatory processes were altered, with reduced tumoral infiltration of neutrophils and CD4 positive T cells, which can be explained by decreased levels of complement factor D (CFD) and C7 components of the complement cascade, an innate immune pathway that influences the adaptive immune response. We tested if the secretome was involved in BRF1-driven tumorigenesis. Unbiased proteomic analysis on BRF1-overexpresing PC3 cells confirmed reduced levels of CFD in the secretome, implicating the complement system in prostate carcinogenesis. We further identify that expression of C7 significantly correlates with expression of CD4 and has the potential to alter clinical outcome in human prostate cancer, where low levels of C7 associate with poorer prognosis

    Global, regional, and national burden of colorectal cancer and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

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    Funding: F Carvalho and E Fernandes acknowledge support from Fundação para a Ciência e a Tecnologia, I.P. (FCT), in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy i4HB; FCT/MCTES through the project UIDB/50006/2020. J Conde acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325). V M Costa acknowledges the grant SFRH/BHD/110001/2015, received by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT), IP, under the Norma Transitória DL57/2016/CP1334/CT0006.proofepub_ahead_of_prin

    Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

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    Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

    RNA polymerase III transcription deregulation: a study on Brf1 overexpression in prostate cancer

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    RNA Polymerase III (Poll III) contributes to about 10% of nuclear transcription and is essential for the synthesis of short untranslated transcripts, including tRNA and 5S rRNA. Pol III deregulation has been implicated in driving cellular proliferation and transformation, along with increased expression of a number of Pol III specific transcription factors and transcripts. The significance of Pol III in clinical pathology, including that of human malignancies, remains to be formally tested. Using prostate cancer as a model, two key components of the Pol III complex, namely Brf1 and tRNAiMet, were investigated. The expression patterns of Brf1 and tRNAiMet were studied in this thesis using immunohistochemistry (IHC) and in situ hybridisation (ISH) respectively. Brf1, a subunit of transcription factor IIIB (TFIIIB), was detected predominantly in the nucleus with heterogenous staining intensity, its presence ranging from weak to strong. Examination across a wide range of tissue types and organs, both normal and tumour tissues revealed high levels of Brf1 expression in the epithelium. In addition, Brf1 expression could also be detected in connective tissues and, to a lesser extent, in muscular and nervous tissues. A number of tumour types exhibited elevated expression of Brf1 protein relative to their normal control tissues. These included prostate adenocarcinoma, B-cell lymphoma and, interestingly, tumours arising from connective tissues (sarcoma, fibrosarcoma and chondrosarcoma). As expected, tRNAiMet expression, as revealed by ISH analysis, was mostly observed in the cytoplasm, although some nuclear staining was also present. Similar to Brf1, tRNAiMet expression was detected predominantly in epithelial tissues such as the skin epidermis, prostate gland and epithelial lining of the cervix. A number of tumours were found to overexpress tRNAiMet. These included breast ductal carcinoma, oesophageal carcinoma and melanoma. The clinical impact of Brf1 and tRNAiMet overexpression was examined using tissue microarrays (TMA) containing tissue samples obtained from patients with prostate cancer (PCa) and benign prostate hyperplasia (BPH). Collectively, data from two independent patient cohorts, Glasgow TMA: BPH (n=21), PCa (n=151) and Newcastle TMA: BPH (n=113), PCa (n=365), showed that Brf1 expression was upregulated in prostate cancer relative to BPH (p=0.0034). Brf1 expression was not found to be associated with the following clinical and biologic parameters: Gleason sum score (indicative of tumour differentiation and morphology, p=0.653); prostate specific antigen (PSA level, indicative of tumour bulk or volume, p=0.381) and Ki-67 expression (signifying cellular proliferation, p=0.034). However, and importantly, within the prostate cancer patient cohorts studied, high Brf1 expression was associated with a significantly less favourable survival outcome (Kaplan Meier analysis, p<0.001). Together, the data presented in this study support the relevance of Brf1 and tRNAiMet overexpression as part of Pol III deregulation in tumours, especially of epithelial origin. This study also suggests the potential application of Brf1 as a prognostic marker in cancer, however, this warrants a further study

    An Absorption Capacity Investigation of New Absorbent Based On Polyurethane Foams and Rice Straw for Oil Spill Cleanup

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    Spilled oil has been considering as extremely serious disaster in the maritime field and oil exploration, and its effects lasted for decades, even hundreds of years. Oil spill treatment and recovery were the difficult and complicated issues due to the conditions of nature environment. In this work, rice straw- agricultural residue in Vietnam – with 205 k g/m3 of low density was filled in porous polyurethan matrix in fabrication process of absorbent. The experimental results about oil absorption capacity for this new absorbent material showed that, the absorbed oil mass in case of filling 25% of rice straw mass with 0.5 mm of size was highest, equal to 12.012 g oil/ g absorbent material after 120 minutes of treatment. The result of oil absorption capacity was around 3–4 times higher than that of material fabricated by pristine polyurethan or xenlulozo/lignocellulosic. Besides, fabrication process and SEM analysis were also experimentally carried out in this work
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