142 research outputs found

    Sensitive and selective Affimer-functionalised interdigitated electrode-based capacitive biosensor for Her4 protein tumour biomarker detection

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    A novel Affimer-functionalised interdigitated electrode-based capacitive biosensor platform was developed for detection and estimation of Her4, a protein tumour biomarker, in undiluted serum. An anti-Her4 Affimer with a C-terminal cysteine was used to create the bio-recognition layer via self-assembly on gold interdigitated electrodes for the sensor fabrication. Electrochemical impedance spectroscopy (EIS) in the absence of redox markers was used to evaluate the sensor performance by monitoring the changes in capacitance. The Affimer sensor in buffer and in undiluted serum demonstrated high sensitivity with a broad dynamic range from 1 pM to 100 nM and a limit of detection lower than 1 pM both in buffer and in serum. Furthermore, the Affimer sensor demonstrated excellent specificity with negligible interference from serum proteins, suggesting resilience to non-specific binding. The sensing ability of the present Affimer sensor in spiked undiluted serum suggests its potential for a new range of Affimer-based sensors. The fabricated Affimer sensor can thus be further adapted with other probes having affinities to other biomarkers for a new range of biosensors

    Crohn's Disease Exacerbation Induced by Edwardsiella tarda Gastroenteritis

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    Exacerbations of Crohn's disease are not infrequently associated with bacterial gastroenteritis. The recognition of synchronous infections in such patients is vital for the initiation of appropriate antimicrobial therapy. Furthermore, the detection of active bacterial infections may lead the clinician to delay starting biological therapy. We report here a man presenting with an exacerbation of his Crohn's disease during a trip to Thailand. Stool cultures were positive for the unusual gut pathogen Edwardsiella tarda. The patient's symptoms resolved with concurrent antibiotic and steroid therapy. This finding demonstrates the value of performing stool culture in all patients presenting with exacerbations of inflammatory bowel diseases

    The State of the Art of Medical Imaging Technology: from Creation to Archive and Back

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    Medical imaging has learnt itself well into modern medicine and revolutionized medical industry in the last 30 years. Stemming from the discovery of X-ray by Nobel laureate Wilhelm Roentgen, radiology was born, leading to the creation of large quantities of digital images as opposed to film-based medium. While this rich supply of images provides immeasurable information that would otherwise not be possible to obtain, medical images pose great challenges in archiving them safe from corrupted, lost and misuse, retrievable from databases of huge sizes with varying forms of metadata, and reusable when new tools for data mining and new media for data storing become available. This paper provides a summative account on the creation of medical imaging tomography, the development of image archiving systems and the innovation from the existing acquired image data pools. The focus of this paper is on content-based image retrieval (CBIR), in particular, for 3D images, which is exemplified by our developed online e-learning system, MIRAGE, home to a repository of medical images with variety of domains and different dimensions. In terms of novelties, the facilities of CBIR for 3D images coupled with image annotation in a fully automatic fashion have been developed and implemented in the system, resonating with future versatile, flexible and sustainable medical image databases that can reap new innovations

    Effect of Curcuma longa and Ocimum sanctum on myocardial apoptosis in experimentally induced myocardial ischemic-reperfusion injury

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    BACKGROUND: In the present investigation, the effect of Curcuma longa (Cl) and Ocimum sanctum (Os) on myocardial apoptosis and cardiac function was studied in an ischemia and reperfusion (I-R) model of myocardial injury. METHODS: Wistar albino rats were divided into four groups and orally fed saline once daily (sham, control IR) or Cl (100 mg/kg; Cl-IR) or Os (75 mg/kg; Os-IR) respectively for 1 month. On the 31(st )day, in the rats of the control IR, Cl-IR and Os-IR groups LAD occlusion was undertaken for 45 min, and reperfusion was allowed for 1 h. The hemodynamic parameters{mean arterial pressure (MAP), heart rate (HR), left ventricular end-diastolic pressure (LVEDP), left ventricular peak positive (+) LVdP/dt (rate of pressure development) and negative (-) LVdP/dt (rate of pressure decline)} were monitored at pre-set points throughout the experimental duration and subsequently, the animals were sacrificed for immunohistopathological (Bax, Bcl-2 protein expression & TUNEL positivity) and histopathological studies. RESULTS: Chronic treatment with Cl significantly reduced TUNEL positivity (p < 0.05), Bax protein (p < 0.001) and upregulated Bcl-2 (p < 0.001) expression in comparison to control IR group. In addition, Cl demonstrated mitigating effects on several myocardial injury induced hemodynamic {(+)LVdP/dt, (-) LVdP/dt & LVEDP} and histopathological perturbations. Chronic Os treatment resulted in modest modulation of the hemodynamic alterations (MAP, LVEDP) but failed to demonstrate any significant antiapoptotic effects and prevent the histopathological alterations as compared to control IR group. CONCLUSION: In the present study, significant cardioprotection and functional recovery demonstrated by Cl may be attributed to its anti-apoptotic property. In contrast to Os, Cl may attenuate cell death due to apoptosis and prevent the impairment of cardiac performance

    Cross platform microarray analysis for robust identification of differentially expressed genes

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    <p>Abstract</p> <p>Background</p> <p>Microarrays have been widely used for the analysis of gene expression and several commercial platforms are available. The combined use of multiple platforms can overcome the inherent biases of each approach, and may represent an alternative that is complementary to RT-PCR for identification of the more robust changes in gene expression profiles.</p> <p>In this paper, we combined statistical and functional analysis for the cross platform validation of two oligonucleotide-based technologies, Affymetrix (AFFX) and Applied Biosystems (ABI), and for the identification of differentially expressed genes.</p> <p>Results</p> <p>In this study, we analysed differentially expressed genes after treatment of an ovarian carcinoma cell line with a cell cycle inhibitor. Treated versus control RNA was analysed for expression of 16425 genes represented on both platforms.</p> <p>We assessed reproducibility between replicates for each platform using CAT plots, and we found it high for both, with better scores for AFFX. We then applied integrative correlation analysis to assess reproducibility of gene expression patterns across studies, bypassing the need for normalizing expression measurements across platforms. We identified 930 genes as differentially expressed on AFFX and 908 on ABI, with ~80% common to both platforms. Despite the different absolute values, the range of intensities of the differentially expressed genes detected by each platform was similar. ABI showed a slightly higher dynamic range in FC values, which might be associated with its detection system. 62/66 genes identified as differentially expressed by Microarray were confirmed by RT-PCR.</p> <p>Conclusion</p> <p>In this study we present a cross-platform validation of two oligonucleotide-based technologies, AFFX and ABI. We found good reproducibility between replicates, and showed that both platforms can be used to select differentially expressed genes with substantial agreement. Pathway analysis of the affected functions identified themes well in agreement with those expected for a cell cycle inhibitor, suggesting that this procedure is appropriate to facilitate the identification of biologically relevant signatures associated with compound treatment. The high rate of confirmation found for both common and platform-specific genes suggests that the combination of platforms may overcome biases related to probe design and technical features, thereby accelerating the identification of trustworthy differentially expressed genes.</p

    Nutlin-3, the small-molecule inhibitor of MDM2, promotes senescence and radiosensitises laryngeal carcinoma cells harbouring wild-type p53

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    BACKGROUND: Primary radiotherapy (RT) is a mainstay of treatment for laryngeal squamous cell carcinoma (LSCC). Although the cure rates for early (T1) vocal cord tumours are high, RT proves ineffective in up to a third of T3 carcinomas. Moreover, RT is associated with debilitating early- and late-treatment-related toxicity, thus finding means to de-escalate therapy, while retaining/augmenting therapeutic effectiveness, is highly desirable. p53 is a key mediator of radiation responses; we therefore investigated whether Nutlin-3, a small-molecule inhibitor of MDM2 (mouse double minute 2; an essential negative regulator of p53), might radiosensitise LSCC cells. METHODS: We performed clonogenic assays to measure radiosensitivity in a panel of LSCC cell lines (for which we determined p53 mutational status) in the presence and absence of Nutlin-3. RESULTS: LSCC cells harbouring wild-type p53 were significantly radiosensitised by Nutlin-3 (P&lt;0.0001; log-rank scale), and displayed increased cell cycle arrest and significantly increased senescence (P&lt;0.001) in the absence of increased apoptosis; thus, our data suggest that senescence may mediate this increased radiosensitivity. CONCLUSION: This is the first study showing Nutlin-3 as an effective radiosensitiser in LSCC cells that retain wild-type p53. The clinical application of Nutlin-3 might improve local recurrence rates or allow treatment de-escalation in these patients

    Triose Phosphate Isomerase Deficiency Is Caused by Altered Dimerization–Not Catalytic Inactivity–of the Mutant Enzymes

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    Triosephosphate isomerase (TPI) deficiency is an autosomal recessive disorder caused by various mutations in the gene encoding the key glycolytic enzyme TPI. A drastic decrease in TPI activity and an increased level of its substrate, dihydroxyacetone phosphate, have been measured in unpurified cell extracts of affected individuals. These observations allowed concluding that the different mutations in the TPI alleles result in catalytically inactive enzymes. However, despite a high occurrence of TPI null alleles within several human populations, the frequency of this disorder is exceptionally rare. In order to address this apparent discrepancy, we generated a yeast model allowing us to perform comparative in vivo analyses of the enzymatic and functional properties of the different enzyme variants. We discovered that the majority of these variants exhibit no reduced catalytic activity per se. Instead, we observed, the dimerization behavior of TPI is influenced by the particular mutations investigated, and by the use of a potential alternative translation initiation site in the TPI gene. Additionally, we demonstrated that the overexpression of the most frequent TPI variant, Glu104Asp, which displays altered dimerization features, results in diminished endogenous TPI levels in mammalian cells. Thus, our results reveal that enzyme deregulation attributable to aberrant dimerization of TPI, rather than direct catalytic inactivation of the enzyme, underlies the pathogenesis of TPI deficiency. Finally, we discovered that yeast cells expressing a TPI variant exhibiting reduced catalytic activity are more resistant against oxidative stress caused by the thiol-oxidizing reagent diamide. This observed advantage might serve to explain the high allelic frequency of TPI null alleles detected among human populations

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

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    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

    HIV-1 Env associates with HLA-C free-chains at the cell membrane modulating viral infectivity

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    HLA-C has been demonstrated to associate with HIV-1 envelope glycoprotein (Env). Virions lacking HLA-C have reduced infectivity and increased susceptibility to neutralizing antibodies. Like all others MHC-I molecules, HLA-C requires \u3b22-microglobulin (\u3b22m) for appropriate folding and expression on the cell membrane but this association is weaker, thus generating HLA-C free-chains on the cell surface. In this study, we deepen the understanding of HLA-C and Env association by showing that HIV-1 specifically increases the amount of HLA-C free chains, not bound to \u3b22m, on the membrane of infected cells. The association between Env and HLA-C takes place at the cell membrane requiring \u3b22m to occur. We report that the enhanced infectivity conferred to HIV-1 by HLA-C specifically involves HLA-C free chain molecules that have been correctly assembled with \u3b22m. HIV-1 Env-pseudotyped viruses produced in the absence of \u3b22m are less infectious than those produced in the presence of \u3b22m. We hypothesize that the conformation and surface expression of HLA-C molecules could be a discriminant for the association with Env. Binding stability to \u3b22m may confer to HLA-C the ability to preferentially act either as a conventional immune-competent molecule or as an accessory molecule involved in HIV-1 infectivity

    Modern approach to numerical modelling of anchored protective structures

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    radu je opisan suvremeni pristup numeričkom modeliranju sidrenih zaštitnih konstrukcija s osvrtom na iskustva u primjeni računalnog programa Plaxis 2D i modela tla s izotropnim očvršćivanjem. Objašnjena su osnovna obilježja u ponašanju tla u dreniranim i nedreniranim uvjetima za naprezanja koja se pojavljuju pri iskopu građevne jame. Prikazan je primjer simulacije sidrene zaštitne konstrukcije i dane su smjernice za strategiju odabira parametara materijala HSs modela tla.modern approach to numerical modelling of anchored protective structures is presented in the paper, and an overview is given of experience gained in the use of the Plaxis 2D computer program, and soil model with isotropic strengthening. Basic properties of soil in drained and undrained conditions, due to stress occurring during foundation pit excavation, are explained. An example involving simulation of an anchored protective structure is presented, and guidelines for the selection of soil materials for the HSs soil model are given
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