4,528 research outputs found

    Albumin concentrations are primarily determined by the body cell mass and the systemic inflammatory response in cancer patients with weight loss

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    The association between hypoalbuminemia and poor prognosis in patients with cancer is well recognized. However, the factors that contribute to the fall in albumin concentrations are not well understood. In the present study, we examined the relationship between circulating albumin concentrations, weight loss, the body cell mass (measured using total body potassium), and the presence of an inflammatory response (measured using C- reactive protein) in male patients (n=40) with advanced lung or gastrointestinal cancer. Albumin concentrations were significantly correlated with the percent ideal body weight (r=0.390, p lt 0.05), extent of reported weight loss (r=-0.492, p lt 0.01), percent predicted total body potassium (adjusted for age, height, and weight, r=0.686, p lt 0.001), and logo C-reactive protein concentrations (r=-0.545, p lt 0.001). On multiple regression analysis, the percent predicted total body potassium and log(10) C-reactive protein concentrations accounted for 63% of the variation in albumin concentrations (r(2) = 0.626, p lt 0.001). The interrelationship between albumin, body cell mass, and the inflammatory response is consistent with the concept that the presence of an ongoing inflammatory response contributes to the progressive loss of these vital protein components of the body and the subsequent death of patients with advanced cancer

    Size-Dependent Relationships between Protein Stability and Thermal Unfolding Temperature Have Important Implications for Analysis of Protein Energetics and High-Throughput Assays of Protein-Ligand Interactions

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    Changes in protein stability are commonly reported as changes in the melting temperature, ΔTM, or as changes in unfolding free energy at a particular temperature, ΔΔG°. Using data for 866 mutants from 16 proteins, we examine the relationship between ΔΔG° and ΔTM. A linear relationship is observed for each protein. The slopes of the plots of ΔTM vs ΔΔG° for different proteins scale as N–1, where N is the number of residues in the protein. Thus, a given change in ΔG° causes a much larger change in TM for a small protein relative to the effect observed for a large protein. The analysis suggests that reasonable estimates of ΔΔG° for a mutant can be obtained by interpolating measured values of TM. The relationship between ΔΔG° and ΔTM has implications for the design and interpretation of high-throughput assays of protein–ligand binding. So-called thermal shift assays rely upon the increase in stability which results from ligand binding to the folded state. Quantitative relationships are derived which show that the observed thermal shift, ΔTM, scales as N–1. Hence, thermal shift assays are considerably less sensitive for ligand binding to larger proteins

    Fractal analysis of right ventricular trabeculae in pulmonary hypertension

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    Purpose: To measure right ventricular (RV) trabecular complexity by its fractal dimension (FD) in healthy subjects and patients with pulmonary hypertension (PH) and assess its relationship to hemodynamic and functional parameters, and future cardiovascular events. Materials and methods: This retrospective study used data acquired from May 2004 to October 2013 for 256 patients with newly-diagnosed PH that underwent cardiac magnetic resonance (CMR) imaging, right heart catheterization and six-minute walk distance testing with a median follow-up of 4.0 years. 256 healthy controls underwent CMR only. Biventricular FD, volumes and function were assessed on short-axis cine images. Reproducibility was assessed by intraclass correlation coefficient, correlation between variables was assessed by Pearson’s correlation test, and mortality prediction compared by univariable and multivariable Cox regression analysis. Results: RV-FD reproducibility had an intraclass correlation coefficient of 0.97 (95% confidence interval [CI]: 0.96, 0.98). RV-FD was higher in PH patients than healthy subjects (median 1.310, inter-quartile range [IQR] 1.281-1.341 vs 1.264, 1.242-1.295, P <.001) with the greatest difference near the apex. RV-FD was associated with pulmonary vascular resistance (r=0.30, P <.001). In univariable Cox regression analysis, RV-FD was a significant predictor of death (hazards ratio [HR]: 1.256, CI: 1.011, 1.560, P =.04), but in a multivariable analysis did not predict survival independently of conventional parameters of RV remodeling (HR: 1.179, CI: 0.871, 1.596, P =0.29). Conclusion: Fractal analysis of RV trabecular complexity is a highly reproducible measure of remodeling in PH associated with afterload, although the gain in survival prediction over traditional markers is not significant

    Neprilysin Is Required for Angiotensin-(1-7)'s Ability to Enhance Insulin Secretion via Its Proteolytic Activity to Generate Angiotensin-(1-2)

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    Recent work has renewed interest in therapies targeting the renin-angiotensin system (RAS) to improve β-cell function in type 2 diabetes. Studies show that generation of angiotensin-(1–7) by ACE2 and its binding to the Mas receptor (MasR) improves glucose homeostasis, partly by enhancing glucose-stimulated insulin secretion (GSIS). Thus, islet ACE2 upregulation is viewed as a desirable therapeutic goal. Here, we show that, although endogenous islet ACE2 expression is sparse, its inhibition abrogates angiotensin-(1–7)–mediated GSIS. However, a more widely expressed islet peptidase, neprilysin, degrades angiotensin-(1–7) into several peptides. In neprilysin-deficient mouse islets, angiotensin-(1–7) and neprilysin-derived degradation products angiotensin-(1–4), angiotensin-(5–7), and angiotensin-(3–4) failed to enhance GSIS. Conversely, angiotensin-(1–2) enhanced GSIS in both neprilysin-deficient and wild-type islets. Rather than mediating this effect via activation of the G-protein–coupled receptor (GPCR) MasR, angiotensin-(1–2) was found to signal via another GPCR, namely GPCR family C group 6 member A (GPRC6A). In conclusion, in islets, intact angiotensin-(1–7) is not the primary mediator of beneficial effects ascribed to the ACE2/angiotensin-(1–7)/MasR axis. Our findings warrant caution for the concurrent use of angiotensin-(1–7) compounds and neprilysin inhibitors as therapies for diabetes

    A novel isolator-based system promotes viability of human embryos during laboratory processing

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    In vitro fertilisation (IVF) and related technologies are arguably the most challenging of all cell culture applications. The starting material is a single cell from which one aims to produce an embryo capable of establishing a pregnancy eventually leading to a live birth. Laboratory processing during IVF treatment requires open manipulations of gametes and embryos, which typically involves exposure to ambient conditions. To reduce the risk of cellular stress, we have developed a totally enclosed system of interlinked isolator-based workstations designed to maintain oocytes and embryos in a physiological environment throughout the IVF process. Comparison of clinical and laboratory data before and after the introduction of the new system revealed that significantly more embryos developed to the blastocyst stage in the enclosed isolator-based system compared with conventional open-fronted laminar flow hoods. Moreover, blastocysts produced in the isolator-based system contained significantly more cells and their development was accelerated. Consistent with this, the introduction of the enclosed system was accompanied by a significant increase in the clinical pregnancy rate and in the proportion of embryos implanting following transfer to the uterus. The data indicate that protection from ambient conditions promotes improved development of human embryos. Importantly, we found that it was entirely feasible to conduct all IVF-related procedures in the isolator-based workstations

    Video-assisted mediastinoscopic transhiatal esophagectomy combined with laparoscopy for esophageal cancer

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    <p>Abstract</p> <p>Background</p> <p>Minimally invasive transhiatal esophagectomy for esophageal cancer includes mediastinoscopic and laparoscopic transhiatal esophagectomy. It is inadequate in both two techniques. It is impossible to dissect the lower esophagus with single mediastinoscopy or the upper and middle esophagus with single laparoscopy. We use mediastinoscopy combined with laparoscopy to dissect the whole esophagus and stomach including lymph node dissection. In addition, laparoscopic gastric mobilization leads to less trauma than an open gastroplasty.</p> <p>Methods</p> <p>40 cases of video-assisted mediastinoscopic transhiatal esophagectomy were performed and divided into two groups.32 patients were received surgical therapy of single mediastinoscopic esophagectomy with open gastroplasty in group A, while 8 patients were received surgical therapy of mediastinoscopic esophagectomy combined with laparoscopic lower esophageal and gastric dissection in group B. The perioperative complications were recorded.</p> <p>Results</p> <p>Video-assisted mediastinoscopic transhiatal esophagectomy was performed successfully both in group A and B. It suggested that mediastinoscopy combined with laparoscopy be better than single mediastinoscopy because of less blood loss, less pain, shorter ICU stay and complete lower mediastinal lymph nodes resection.</p> <p>Conclusions</p> <p>Video-assisted mediastinoscopic transhiatal esophagectomy combined with laparoscopy is a safe and minimally invasive technique with whole esophagus and mediastinal lymph node dissection in the clear visualization of the mediastinum, reducing the abdominal trauma.</p

    Regulation of neutrophil senescence by microRNAs

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    Neutrophils are rapidly recruited to sites of tissue injury or infection, where they protect against invading pathogens. Neutrophil functions are limited by a process of neutrophil senescence, which renders the cells unable to respond to chemoattractants, carry out respiratory burst, or degranulate. In parallel, aged neutrophils also undergo spontaneous apoptosis, which can be delayed by factors such as GMCSF. This is then followed by their subsequent removal by phagocytic cells such as macrophages, thereby preventing unwanted inflammation and tissue damage. Neutrophils translate mRNA to make new proteins that are important in maintaining functional longevity. We therefore hypothesised that neutrophil functions and lifespan might be regulated by microRNAs expressed within human neutrophils. Total RNA from highly purified neutrophils was prepared and subjected to microarray analysis using the Agilent human miRNA microarray V3. We found human neutrophils expressed a selected repertoire of 148 microRNAs and that 6 of these were significantly upregulated after a period of 4 hours in culture, at a time when the contribution of apoptosis is negligible. A list of predicted targets for these 6 microRNAs was generated from http://mirecords.biolead.org and compared to mRNA species downregulated over time, revealing 83 genes targeted by at least 2 out of the 6 regulated microRNAs. Pathway analysis of genes containing binding sites for these microRNAs identified the following pathways: chemokine and cytokine signalling, Ras pathway, and regulation of the actin cytoskeleton. Our data suggest that microRNAs may play a role in the regulation of neutrophil senescence and further suggest that manipulation of microRNAs might represent an area of future therapeutic interest for the treatment of inflammatory disease
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