471 research outputs found

    Immunohistochemical Evaluation of Insulin-like Growth Factor I Receptor Status in Cervical Cancer Specimens

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    The insulin-like growth factor I receptor (IGF-IR) is exceptionally overexpressed in many cervicalcancer-derived cell lines. It is postulated that a decrease of p53 protein levels due to human papillomavirus (HPV) infection may contribute to the up-regulation of IGF-IR expression in cervical cancer cells because transcription of IGF-IR is strictly down-regulated by p53. To evaluate this fact in clinical cervical cancer specimens, we checked the expression levels and activated status of IGF-IR by immunohistochemistry. Formalin-fixed and paraffin-embedded specimens obtained by conization or hysterectomy were stained with anti-IGF-IR and with an antibody recognizing phosphorylated tyrosine at its c-terminus. The expression levels of IGF-IR were significantly high in cervical intraepithelial neoplasia (CIN) III and invasive cancer specimens. Phosphorylation of IGF-IR was promoted in all CIN and invasive cancer specimens, and its intensity was related to the promotion of lesions. Interestingly, IGF-IR overexpression was missing in the basal layer of CIN I and II lesions, whereas it was evenly distributed in CIN III and invasive cancer lesions. This IGF-IR overexpression pattern may be utilized in the diagnosis of HPV infection status in CIN lesions.</p

    Numerical study of the effects of crack location on creep crack growth in weldment

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    A numerical study on the effects of crack location on creep crack growth, in a P91 weldment, was carried out using a finite element package (ABAQUS). Models of compact tension specimens were used. The obtained results showed that, the creep crack growth in the weld metal are much higher than that in the parent metal. However, the creep crack growth in cross-weld specimens is controlled by the properties of the weakest component of the weld. This highlights the importance of the heat affected zone (HAZ) as the weakest region of the weldment. Effects of the width of HAZ are presented, too

    Association between timing of speech and language therapy initiation and outcomes among post-extubation dysphagia patients: a multicenter retrospective cohort study

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    Background Post-extubation dysphagia (PED) is recognized as a common complication in the intensive care unit (ICU). Speech and language therapy (SLT) can potentially help improve PED; however, the impact of the timing of SLT initiation on persistent PED has not been well investigated. This study aimed to examine the timing of SLT initiation and its effect on patient outcomes after extubation in the ICU. Methods We conducted this multicenter, retrospective, cohort study, collecting data from eight ICUs in Japan. Patients aged >= 20 years with orotracheal intubation and mechanical ventilation for longer than 48 h, and those who received SLT due to PED, defined as patients with modified water swallowing test scores of 3 or lower, were included. The primary outcome was dysphagia at hospital discharge, defined as functional oral intake scale score < 5 or death after extubation. Secondary outcomes included dysphagia or death at the seventh, 14th, or 28th day after extubation, aspiration pneumonia, and in-hospital mortality. Associations between the timing of SLT initiation and outcomes were determined using multivariable logistic regression. Results A total of 272 patients were included. Of them, 82 (30.1%) patients exhibited dysphagia or death at hospital discharge, and their time spans from extubation to SLT initiation were 1.0 days. The primary outcome revealed that every day of delay in SLT initiation post-extubation was associated with dysphagia or death at hospital discharge (adjusted odds ratio (AOR), 1.09; 95% CI, 1.02-1.18). Similarly, secondary outcomes showed associations between this per day delay in SLT initiation and dysphagia or death at the seventh day (AOR, 1.28; 95% CI, 1.05-1.55), 14th day (AOR, 1.34; 95% CI, 1.13-1.58), or 28th day (AOR, 1.21; 95% CI, 1.07-1.36) after extubation and occurrence of aspiration pneumonia (AOR, 1.09; 95% CI, 1.02-1.17), while per day delay in post-extubation SLT initiation did not affect in-hospital mortality (AOR, 1.04; 95% CI, 0.97-1.12). Conclusions Delayed initiation of SLT in PED patients was associated with persistent dysphagia or death. Early initiation of SLT may prevent this complication post-extubation. A randomized controlled study is needed to validate these results

    Glycan shifting on hepatitis C virus (HCV) E2 glycoprotein is a mechanism for escape from broadly neutralizing antibodies

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    Hepatitis C virus (HCV) infection is a major cause of liver disease and hepatocellular carcinoma. Glycan shielding has been proposed to be a mechanism by which HCV masks broadly neutralizing epitopes on its viral glycoproteins. However, the role of altered glycosylation in HCV resistance to broadly neutralizing antibodies is not fully understood. Here, we have generated potent HCV neutralizing antibodies hu5B3.v3 and MRCT10.v362 that, similar to the previously described AP33 and HCV1, bind to a highly conserved linear epitope on E2. We utilize a combination of in vitro resistance selections using the cell culture infectious HCV and structural analyses to identify mechanisms of HCV resistance to hu5B3.v3 and MRCT10.v362. Ultra deep sequencing from in vitro HCV resistance selection studies identified resistance mutations at asparagine N417 (N417S, N417T and N417G) as early as 5 days post treatment. Comparison of the glycosylation status of soluble versions of the E2 glycoprotein containing the respective resistance mutations revealed a glycosylation shift from N417 to N415 in the N417S and N417T E2 proteins. The N417G E2 variant was glycosylated neither at residue 415 nor at residue 417 and remained sensitive to MRCT10.v362. Structural analyses of the E2 epitope bound to hu5B3.v3 Fab and MRCT10.v362 Fab using X-ray crystallography confirmed that residue N415 is buried within the antibody–peptide interface. Thus, in addition to previously described mutations at N415 that abrogate the β-hairpin structure of this E2 linear epitope, we identify a second escape mechanism, termed glycan shifting, that decreases the efficacy of broadly neutralizing HCV antibodies

    Indirect two-sided relative ranking: a robust similarity measure for gene expression data

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    <p>Abstract</p> <p>Background</p> <p>There is a large amount of gene expression data that exists in the public domain. This data has been generated under a variety of experimental conditions. Unfortunately, these experimental variations have generally prevented researchers from accurately comparing and combining this wealth of data, which still hides many novel insights.</p> <p>Results</p> <p>In this paper we present a new method, which we refer to as indirect two-sided relative ranking, for comparing gene expression profiles that is robust to variations in experimental conditions. This method extends the current best approach, which is based on comparing the correlations of the up and down regulated genes, by introducing a comparison based on the correlations in rankings across the entire database. Because our method is robust to experimental variations, it allows a greater variety of gene expression data to be combined, which, as we show, leads to richer scientific discoveries.</p> <p>Conclusions</p> <p>We demonstrate the benefit of our proposed indirect method on several datasets. We first evaluate the ability of the indirect method to retrieve compounds with similar therapeutic effects across known experimental barriers, namely vehicle and batch effects, on two independent datasets (one private and one public). We show that our indirect method is able to significantly improve upon the previous state-of-the-art method with a substantial improvement in recall at rank 10 of 97.03% and 49.44%, on each dataset, respectively. Next, we demonstrate that our indirect method results in improved accuracy for classification in several additional datasets. These datasets demonstrate the use of our indirect method for classifying cancer subtypes, predicting drug sensitivity/resistance, and classifying (related) cell types. Even in the absence of a known (i.e., labeled) experimental barrier, the improvement of the indirect method in each of these datasets is statistically significant.</p

    Stomatal Function Requires Pectin De-methyl-esterification of the Guard Cell Wall

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    Stomatal opening and closure depends on changes in turgor pressure acting within guard cells to alter cell shape. The extent of these shape changes is limited by the mechanical properties of the cells, which will be largely dependent on the structure of the cell walls. Although it has long been observed that guard cells are anisotropic due to differential thickening and the orientation of cellulose microfibrils, our understanding of the composition of the cell wall that allows them to undergo repeated swelling and deflation remains surprisingly poor. Here, we show that the walls of guard cells are rich in unesterified pectins. We identify a pectin methylesterase gene, PME6, which is highly expressed in guard cells and required for stomatal function. pme6-1 mutant guard cells have walls enriched in methyl-esterified pectin and show a decreased dynamic range in response to triggers of stomatal opening/closure, including elevated osmoticum, suggesting that abrogation of stomatal function reflects a mechanical change in the guard cell wall. Altered stomatal function leads to increased conductance and evaporative cooling, as well as decreased plant growth. The growth defect of the pme6-1 mutant is rescued by maintaining the plants in elevated CO2, substantiating gas exchange analyses, indicating that the mutant stomata can bestow an improved assimilation rate. Restoration of PME6 rescues guard cell wall pectin methyl-esterification status, stomatal function, and plant growth. Our results establish a link between gene expression in guard cells and their cell wall properties, with a corresponding effect on stomatal function and plant physiology

    Altered longevity-assurance activity of p53:p44 in the mouse causes memory loss, neurodegeneration and premature death

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    The longevity-assurance activity of the tumor suppressor p53 depends on the levels of Δ40p53 (p44), a short and naturally occurring isoform of the p53 gene. As such, increased dosage of p44 in the mouse leads to accelerated aging and short lifespan. Here we show that mice homozygous for a transgene encoding p44 (p44+/+) display cognitive decline and synaptic impairment early in life. The synaptic deficits are attributed to hyperactivation of insulin-like growth factor 1 receptor (IGF-1R) signaling and altered metabolism of the microtubule-binding protein tau. In fact, they were rescued by either Igf1r or Mapt haploinsufficiency. When expressing a human or a ‘humanized’ form of the amyloid precursor protein (APP), p44+/+ animals developed a selective degeneration of memory-forming and -retrieving areas of the brain, and died prematurely. Mechanistically, the neurodegeneration was caused by both paraptosis- and autophagy-like cell deaths. These results indicate that altered longevity-assurance activity of p53:p44 causes memory loss and neurodegeneration by affecting IGF-1R signaling. Importantly, Igf1r haploinsufficiency was also able to correct the synaptic deficits of APP695/swe mice, a model of Alzheimer’s disease
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