48 research outputs found

    The impact of operative approach on outcome of surgery for gastro-oesophageal tumours

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    <p>Abstract</p> <p>Background</p> <p>The choice of operation for tumours at or around the gastro-oesophageal junction remains controversial with little evidence to support one technique over another. This study examines the prevalence of margin involvement and nodal disease and their impact on outcome following three surgical approaches (Ivor Lewis, transhiatal and left thoraco-laparotomy) for these tumours.</p> <p>Methods</p> <p>A retrospective analysis was conducted of patients undergoing surgery for distal oesophageal and gastro-oesophageal junction tumours by a single surgeon over ten years. Comparisons were undertaken in terms of tumour clearance, nodal yield, postoperative morbidity, mortality, and median survival. All patients were followed up until death or the end of the data collection (mean follow up 33.2 months).</p> <p>Results</p> <p>A total of 104 patients were operated on of which 102 underwent resection (98%). Median age was 64.1 yrs (range 32.1–79.4) with 77 males and 25 females. Procedures included 29 Ivor Lewis, 31 transhiatal and 42 left-thoraco-laparotomies. Postoperative mortality was 2.9% and median survival 23 months. Margin involvement was 24.1% (two distal, one proximal and 17 circumferential margins). Operative approach had no significant effect on nodal clearance, margin involvement, postoperative mortality or morbidity and survival. Lymph node positive disease had a significantly worse median survival of 15.8 months compared to 39.7 months for node negative (<it>p </it>= 0.007), irrespective of approach.</p> <p>Conclusion</p> <p>Surgical approach had no effect on postoperative mortality, circumferential tumour, nodal clearance or survival. This suggests that the choice of operative approach for tumours at the gastro-oesophageal junction may be based on the individual patient and tumour location rather than surgical dogma.</p

    Impact of viral replication inhibition by entecavir on peripheral T lymphocyte subpopulations in chronic hepatitis B patients

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    <p>Abstract</p> <p>Background</p> <p>To investigate dynamic fluctuations of serum viral load and peripheral T-lymphocyte subpopulations of chronic hepatitis B patients and their correlation during entecavir therapy.</p> <p>Methods</p> <p>Fifty-five patients received entecavir 0.5 mg/d therapy. Serum HBV DNA load was measured by Real-Time-PCR, and the levels of peripheral T-lymphocyte subpopulations by flow cytometry biweekly, every four weeks and every eight weeks during weeks 1–12, 13–24 and 24–48, respectively. Multilevel modelling was used to analyse the relationship between these variables.</p> <p>Results</p> <p>Of the 55 patients, all HBeAg positive and with detectable HBV DNA, the majority (81.8%) had serum levels of HBV DNA over 10<sup>7 </sup>copies per milliliter. HBV viral load dropped sharply during the first two weeks. In 28 and 43 patients, the level became undetectable from week 24 and 48, respectively. Using pre-therapy level as the reference, a significant decrease in CD8<sup>+ </sup>T cells and increase in CD4<sup>+ </sup>T cells were found from week 12. Both parameters and CD4<sup>+</sup>/CD8<sup>+ </sup>ratio steadily improved throughout the 48 weeks. Multilevel analyses showed that the level of decrement of HBV DNA was associated with the increment of T-lymphocyte activities only in the later period (4–48 week). After 4 weeks of therapy, for each log<sub>10 </sub>scale decrement of HBV DNA, the percentage of CD4<sup>+ </sup>lymphocyte was increased by 0.49 and that of CD8<sup>+ </sup>decreased by 0.51.</p> <p>Conclusion</p> <p>T-lymphocyte subpopulations could be restored partially by entecavir treatment in patients with chronic hepatitis B concurrently with reduction of viremia.</p

    Intranasal Delivery of E-Selectin Reduces Atherosclerosis in ApoE−/− Mice

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    Mucosal tolerance to E-selectin prevents stroke and protects against ischemic brain damage in experimental models of stroke studying healthy animals or spontaneously hypertensive stroke-prone rats. A reduction in inflammation and neural damage was associated with immunomodulatory or “tolerogenic” responses to E-selectin. The purpose of the current study on ApoE deficient mice is to assess the capacity of this stroke prevention innovation to influence atherosclerosis, a major underlying cause for ischemic strokes; human E-selectin is being translated as a potential clinical prevention strategy for secondary stroke. Female ApoE−/− mice received intranasal delivery of E-selectin prior to (pre-tolerization) or simultaneously with initiation of a high-fat diet. After 7 weeks on the high-fat diet, lipid lesions in the aorta, serum triglycerides, and total cholesterol were assessed as markers of atherosclerosis development. We also assessed E-selectin-specific antibodies and cytokine responses, in addition to inflammatory responses that included macrophage infiltration of the aorta and altered gene expression profiles of aortic mRNA. Intranasal delivery of E-selectin prior to initiation of high-fat chow decreased atherosclerosis, serum total cholesterol, and expression of the leucocyte chemoattractant CCL21 that is typically upregulated in atherosclerotic lesions of ApoE−/− mice. This response was associated with the induction of E-selectin specific cells producing the immunomodulatory cytokine IL-10 and immunosuppressive antibody isotypes. Intranasal administration of E-selectin generates E-selectin specific immune responses that are immunosuppressive in nature and can ameliorate atherosclerosis, a major risk factor for ischemic stroke. These results provide additional preclinical support for the potential of induction of mucosal tolerance to E-selectin to prevent stroke

    Alternative Splicing Regulation During C. elegans Development: Splicing Factors as Regulated Targets

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    Alternative splicing generates protein diversity and allows for post-transcriptional gene regulation. Estimates suggest that 10% of the genes in Caenorhabditis elegans undergo alternative splicing. We constructed a splicing-sensitive microarray to detect alternative splicing for 352 cassette exons and tested for changes in alternative splicing of these genes during development. We found that the microarray data predicted that 62/352 (∼18%) of the alternative splicing events studied show a strong change in the relative levels of the spliced isoforms (>4-fold) during development. Confirmation of the microarray data by RT-PCR was obtained for 70% of randomly selected genes tested. Among the genes with the most developmentally regulated alternatively splicing was the hnRNP F/H splicing factor homolog, W02D3.11 – now named hrpf-1. For the cassette exon of hrpf-1, the inclusion isoform comprises 65% of hrpf-1 steady state messages in embryos but only 0.1% in the first larval stage. This dramatic change in the alternative splicing of an alternative splicing factor suggests a complex cascade of splicing regulation during development. We analyzed splicing in embryos from a strain with a mutation in the splicing factor sym-2, another hnRNP F/H homolog. We found that approximately half of the genes with large alternative splicing changes between the embryo and L1 stages are regulated by sym-2 in embryos. An analysis of the role of nonsense-mediated decay in regulating steady-state alternative mRNA isoforms was performed. We found that 8% of the 352 events studied have alternative isoforms whose relative steady-state levels in embryos change more than 4-fold in a nonsense-mediated decay mutant, including hrpf-1. Strikingly, 53% of these alternative splicing events that are affected by NMD in our experiment are not obvious substrates for NMD based on the presence of premature termination codons. This suggests that the targeting of splicing factors by NMD may have downstream effects on alternative splicing regulation

    Striatal Proteomic Analysis Suggests that First L-Dopa Dose Equates to Chronic Exposure

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    L-3,4-dihydroxypheylalanine (L-dopa)-induced dyskinesia represent a debilitating complication of therapy for Parkinson's disease (PD) that result from a progressive sensitization through repeated L-dopa exposures. The MPTP macaque model was used to study the proteome in dopamine-depleted striatum with and without subsequent acute and chronic L-dopa treatment using two-dimensional difference in-gel electrophoresis (2D-DIGE) and mass spectrometry. The present data suggest that the dopamine-depleted striatum is so sensitive to de novo L-dopa treatment that the first ever administration alone would be able (i) to induce rapid post-translational modification-based proteomic changes that are specific to this first exposure and (ii), possibly, lead to irreversible protein level changes that would be not further modified by chronic L-dopa treatment. The apparent equivalence between first and chronic L-dopa administration suggests that priming would be the direct consequence of dopamine loss, the first L-dopa administrations only exacerbating the sensitization process but not inducing it

    Effect of Chemical Mutagens and Carcinogens on Gene Expression Profiles in Human TK6 Cells

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    Characterization of toxicogenomic signatures of carcinogen exposure holds significant promise for mechanistic and predictive toxicology. In vitro transcriptomic studies allow the comparison of the response to chemicals with diverse mode of actions under controlled experimental conditions. We conducted an in vitro study in TK6 cells to characterize gene expression signatures of exposure to 15 genotoxic carcinogens frequently used in European industries. We also examined the dose-responsive changes in gene expression, and perturbation of biochemical pathways in response to these carcinogens. TK6 cells were exposed at 3 dose levels for 24 h with and without S9 human metabolic mix. Since S9 had an impact on gene expression (885 genes), we analyzed the gene expression data from cells cultures incubated with S9 and without S9 independently. The ribosome pathway was affected by all chemical-dose combinations. However in general, no similar gene expression was observed among carcinogens. Further, pathways, i.e. cell cycle, DNA repair mechanisms, RNA degradation, that were common within sets of chemical-dose combination were suggested by clustergram. Linear trends in dose–response of gene expression were observed for Trichloroethylene, Benz[a]anthracene, Epichlorohydrin, Benzene, and Hydroquinone. The significantly altered genes were involved in the regulation of (anti-) apoptosis, maintenance of cell survival, tumor necrosis factor-related pathways and immune response, in agreement with several other studies. Similarly in S9+ cultures, Benz[a]pyrene, Styrene and Trichloroethylene each modified over 1000 genes at high concentrations. Our findings expand our understanding of the transcriptomic response to genotoxic carcinogens, revealing the alteration of diverse sets of genes and pathways involved in cellular homeostasis and cell cycle control

    A Genome-Wide SNP Scan Reveals Novel Loci for Egg Production and Quality Traits in White Leghorn and Brown-Egg Dwarf Layers

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    Availability of the complete genome sequence as well as high-density SNP genotyping platforms allows genome-wide association studies (GWAS) in chickens. A high-density SNP array containing 57,636 markers was employed herein to identify associated variants underlying egg production and quality traits within two lines of chickens, i.e., White Leghorn and brown-egg dwarf layers. For each individual, age at first egg (AFE), first egg weight (FEW), and number of eggs (EN) from 21 to 56 weeks of age were recorded, and egg quality traits including egg weight (EW), eggshell weight (ESW), yolk weight (YW), eggshell thickness (EST), eggshell strength (ESS), albumen height(AH) and Haugh unit(HU) were measured at 40 and 60 weeks of age. A total of 385 White Leghorn females and 361 brown-egg dwarf dams were selected to be genotyped. The genome-wide scan revealed 8 SNPs showing genome-wise significant (P<1.51E-06, Bonferroni correction) association with egg production and quality traits under the Fisher's combined probability method. Some significant SNPs are located in known genes including GRB14 and GALNT1 that can impact development and function of ovary, but more are located in genes with unclear functions in layers, and need to be studied further. Many chromosome-wise significant SNPs were also detected in this study and some of them are located in previously reported QTL regions. Most of loci detected in this study are novel and the follow-up replication studies may be needed to further confirm the functional significance for these newly identified SNPs

    Randomized placebo-controlled trial on azithromycin to reduce the morbidity of bronchiolitis in Indigenous Australian infants: rationale and protocol

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    Background: Acute lower respiratory infections are the commonest cause of morbidity and potentially preventable mortality in Indigenous infants. Infancy is also a critical time for post-natal lung growth and development. Severe or repeated lower airway injury in very young children likely increases the likelihood of chronic pulmonary disorders later in life. Globally, bronchiolitis is the most common form of acute lower respiratory infections during infancy. Compared with non-Indigenous Australian infants, Indigenous infants have greater bacterial density in their upper airways and more severe bronchiolitis episodes. Our study tests the hypothesis that the anti-microbial and anti-inflammatory properties of azithromycin, improve the clinical outcomes of Indigenous Australian infants hospitalised with bronchiolitis.Methods: We are conducting a dual centre, randomised, double-blind, placebo-controlled, parallel group trial in northern Australia. Indigenous infants (aged ≤ 24-months, expected number = 200) admitted to one of two regional hospitals (Darwin, Northern Territory and Townsville, Queensland) with a clinical diagnosis of bronchiolitis and fulfilling inclusion criteria are randomised (allocation concealed) to either azithromycin (30 mg/kg/dose) or placebo administered once weekly for three doses. Clinical data are recorded twice daily and nasopharyngeal swab are collected at enrolment and at the time of discharge from hospital. Primary outcomes are 'length of oxygen requirement' and 'duration of stay,' the latter based upon being judged as 'ready for respiratory discharge'. The main secondary outcome is readmission for a respiratory illness within 6-months of leaving hospital. Descriptive virological and bacteriological (including development of antibiotic resistance) data from nasopharyngeal samples will also be reported.Discussion: Two published studies, both involving different patient populations and settings, as well as different macrolide antibiotics and treatment duration, have produced conflicting results. Our randomised, placebo-controlled trial of azithromycin in Indigenous infants hospitalised with bronchiolitis is designed to determine whether it can reduce short-term (and potentially long-term) morbidity from respiratory illness in Australian Indigenous infants who are at high risk of developing chronic respiratory illness. If azithromycin is efficacious in reducing the morbidly of Indigenous infants hospitalised with bronchiolitis, the intervention would lead to improved short term (and possibly long term) health benefits. Trial registration: Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12610000326099

    Planetary bearing defect detection in a commercial helicopter main gearbox with vibration and acoustic emission

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Helicopter gearboxes significantly differ from other transmission types and exhibit unique behaviors that reduce the effectiveness of traditional fault diagnostics methods. In addition, due to lack of redundancy, helicopter transmission failure can lead to catastrophic accidents. Bearing faults in helicopter gearboxes are difficult to discriminate due to the low signal to noise ratio (SNR) in the presence of gear vibration. In addition, the vibration response from the planet gear bearings must be transmitted via a time-varying path through the ring gear to externally mounted accelerometers, which cause yet further bearing vibration signal suppression. This research programme has resulted in the successful proof of concept of a broadband wireless transmission sensor that incorporates power scavenging whilst operating within a helicopter gearbox. In addition, this paper investigates the application of signal separation techniques in detection of bearing faults within the epicyclic module of a large helicopter (CS-29) main gearbox using vibration and Acoustic Emissions (AE). It compares their effectiveness for various operating conditions. Three signal processing techniques including an adaptive filter, spectral kurtosis and envelope analysis, were combined for this investigation. In addition, this research discusses the feasibility of using AE for helicopter gearbox monitoring
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