371 research outputs found

    The control of lipid metabolism by mRNA splicing in Drosophila

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    The storage of lipids is an evolutionarily conserved process that is important for the survival of organisms during shifts in nutrient availability. Triglycerides are stored in lipid droplets, but the mechanisms of how lipids are stored in these structures are poorly understood. Previous in vitro RNAi screens have implicated several components of the spliceosome in controlling lipid droplet formation and storage, but the in vivo relevance of these phenotypes is unclear. In this study, we identify specific members of the splicing machinery that are necessary for normal triglyceride storage in the Drosophila fat body. Decreasing the expression of the splicing factors U1-70K, U2AF38, U2AF50 in the fat body resulted in decreased triglyceride levels. Interestingly, while decreasing the SR protein 9G8 in the larval fat body yielded a similar triglyceride phenotype, its knockdown in the adult fat body resulted in a substantial increase in lipid stores. This increase in fat storage is due in part to altered splicing of the gene for the beta-oxidation enzyme CPT1, producing an isoform with less enzymatic activity. Together, these data indicate a role for mRNA splicing in regulating lipid storage in Drosophila and provide a link between the regulation of gene expression and lipid homeostasis

    The effect of unfiltered coffee on potential biomarkers for colonic cancer risk in healthy volunteers: a randomized trial

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    Background: Epidemiologic studies suggest that coffee use might protect against colorectal cancer. Inconsistencies as to the effect of coffee use and colorectal cancer between epidemiologic studies might be related to the type of coffee brew. Objective: We studied the effect of unfiltered coffee consumption on putative biomarkers for colonic cancer risk. Design: A total of 64 healthy volunteers (31 men and 33 women), with a mean age of 43 ± 11 years were randomly assigned to two groups in a crossover design, with two intervention periods of 2 weeks separated by a washout period of 8 weeks. Treatments were 1 L of cafetiere (French press) coffee daily or no coffee. At the end of each intervention period, fasting blood samples, colorectal biopsies and 48 h faeces were collected. Results: No effect of coffee on colorectal cell proliferation, assayed by estimating the Proliferating Cell Nuclear Antigen labelling index, was seen. Additionally, no effects were seen on the concentrations of faecal soluble bile acids and colorectal mucosal glutathione S-transferase activity. However, unfiltered coffee significantly increased the glutathione content in the colorectal mucosa by 8% and in plasma by 15%. Other aminothiols in plasma also increased on coffee. Conclusion: Unfiltered coffee does not influence the colorectal mucosal proliferation rate, but might increase the detoxification capacity and anti-mutagenic properties in the colorectal mucosa through an increase in glutathione concentration. Whether this effect indeed contributes to a lower colon cancer risk remains to be established

    Risk-Sensitive Optimal Feedback Control Accounts for Sensorimotor Behavior under Uncertainty

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    Many aspects of human motor behavior can be understood using optimality principles such as optimal feedback control. However, these proposed optimal control models are risk-neutral; that is, they are indifferent to the variability of the movement cost. Here, we propose the use of a risk-sensitive optimal controller that incorporates movement cost variance either as an added cost (risk-averse controller) or as an added value (risk-seeking controller) to model human motor behavior in the face of uncertainty. We use a sensorimotor task to test the hypothesis that subjects are risk-sensitive. Subjects controlled a virtual ball undergoing Brownian motion towards a target. Subjects were required to minimize an explicit cost, in points, that was a combination of the final positional error of the ball and the integrated control cost. By testing subjects on different levels of Brownian motion noise and relative weighting of the position and control cost, we could distinguish between risk-sensitive and risk-neutral control. We show that subjects change their movement strategy pessimistically in the face of increased uncertainty in accord with the predictions of a risk-averse optimal controller. Our results suggest that risk-sensitivity is a fundamental attribute that needs to be incorporated into optimal feedback control models

    Impact of Endoscopic Ultrasonography on (18)F-FDG-PET/CT Upfront Towards Patient Specific Esophageal Cancer Treatment

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    INTRODUCTION: In patients with potentially resectable esophageal cancer (EC), the value of endoscopic ultrasonography (EUS) after fluorine-18 labeled fluorodeoxyglucose positron emission tomography with computed tomography ((18)F-FDG-PET/CT) is questionable. Retrospectively, we assessed the impact of EUS after PET/CT on the given treatment in EC patients. METHODS: During the period 2009-2015, 318 EC patients were staged as T1-4aN0-3M0 with hybrid (18)F-FDG-PET/CT or (18)F-FDG-PET with CT and EUS if applicable in a nonspecific order. We determined the impact of EUS on the given treatment in 279 patients who also were staged with EUS. EUS had clinical consequences if it changed curability, extent of radiation fields or lymph node resection (AJCC stations 2-5), and when the performed fine-needle aspiration (FNA) provided conclusive information of suspicious lymph node. RESULTS: EUS had an impact in 80 (28.7%) patients; it changed the radiation field in 63 (22.6%), curability in 5 (1.8%), lymphadenectomy in 48 (17.2%), and FNA was additional in 21 (7.5%). In patients treated with nCRT (n = 194), EUS influenced treatment in 53 (27.3%) patients; in 38 (19.6%) the radiation field changed, in 3 (1.5%) the curability, in 35 (18.0%) the lymphadenectomy, and in 17 (8.8%) FNA was additional. EUS influenced both the extent of radiation field and nodal resection in 31 (16.0%) nCRT patients. CONCLUSIONS: EUS had an impact on the given treatment in approximately 29%. In most patients, the magnitude of EUS found expression in the extent of radiotherapy target volume delineation to upper/high mediastinal lymph nodes

    Novel cryoballoon 180° ablation system for treatment of Barrett's esophagus-related neoplasia:a first-in-human study

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    Background The novel 180 degrees cryoballoon (CbAS (180) ) enables semicircumferential treatment over a length of 3cm per application. This first-in-human study evaluates its feasibility, efficacy, and safety for the treatment of Barrett's esophagus (BE) neoplasia. Methods This multicenter study consisted of dose-finding and extension phases. Dose-finding started with the lowest dose possible (1.0mm/s). For each dose, six patients were treated circumferentially over a 3-cm length. The dose was increased until the median BE regression was >= 60% without serious adverse events (SAEs). In the extension phase, the dose was confirmed in 19 new patients. The outcomes were technical success, BE regression after one treatment, and SAEs. Results 25 patients (median Prague C0M3) were included (6 dose-finding/19 extension). In two patients, the CbAS (180) could not be applied because of unstable balloon positioning. The technical success rate was 96% (22/23). In the six dose-finding patients, the starting dose resulted in median BE regression of 94% (95% confidence interval [CI] 60%-97%) without SAEs and was thus considered effective. Overall median BE regression was 80% (95%CI 60%-90%). Conclusion Single-session CbAS (180) seems feasible, safe, and effective, and is a promising technique for the treatment of patients with BE neoplasia

    Colon tumor promotion, is it a selection process? Effects of cholate, phytate, and food restriction in rats on proliferation and apoptosis in normal and aberrant crypts

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    Promotion would suppose the selection of initiated cells. We tested the selection of aberrant crypt cells by cholic acid, a colon cancer promoter, and the effect of protectors, phytate and food restriction. After an azoxymethane injection, rats were allocated to a control diet, or to supplements of cholic acid, sodium phytate, or to a 50% food restriction. The proliferation and apoptosis of 1200 crypts were assessed, after immuno-staining for BrdU. Cholic acid increased the proliferation of aberrant crypts but not of normal crypts. Phytate and food restriction decreased the proliferation of normal crypts, but not of aberrant crypts. Apoptosis was not affected by diets. Results support the hypothesis that cholic acid can select initiated cells in the colon
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