146 research outputs found

    An effect of eyestalk ablation on antennular function in the spiny lobster, Panulirus argus

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    1. Unilateral removal of the eyestalk (optic ganglia and medulla terminalis) in the Bermuda spiny lobster, Panulirus argus , disrupts normal initiation of feeding activity via chemo-tactile stimulation of the antennule on the side of the ablation. This deficit may be permanent for it has lasted without apparent remission for over five months and two molts. Unilateral eyestalk ablation also produces a temporary increase in antennular cleaning activity directed toward the antennule on the side of the ablation. This effect seems to last for less than 16 days. Unilateral eyestalk ablation does not appreciably disturb spontaneous antennular movements or responses to mechanical stimulation of the antennule on either side. Nor does it destroy the ability of the lobster to give differential responses to mechanical and chemo-tactile stimuli. Most lobsters recover normal sensory and motor functions in antennules that regenerate after amputation of the distal segment and sensory flagellae. In about 1/3 of the animals, however, some form of sensory or motor abnormality is evident in the regenerated antennule. These deficits are ascribed to occasional failure of regenerating neurons to reform appropriate central connections. They do not resemble the deficits following eyestalk ablation. The medulla terminalis is tentatively proposed as the portion of the nervous system critical for normal antennular function that is removed by eyestalk ablation. There seem to be similarities between the effects of eyestalk ablation in the Crustacea as described here and the effects following destruction of portions of the corpora pedunculata in insects. 1. Einseitige Entfernung des Augenstieles (optische Ganglien und Medulla terminalis) bei der Bermuda-Stachellanguste, Panulirus argus , unterbricht auf der operierten Seite den Beginn der normalen Freß-tätigkeit, die durch chemische und taktile Reizung der Antennula eingeleitet wird. Diese Störung kann irreversibel sein, denn sie überdauerte in über 5 Monaten zwei Häutungen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47096/1/359_2004_Article_BF00340474.pd

    Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) overexpression in pancreatic ductal adenocarcinoma correlates with poor survival

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    <p>Abstract</p> <p>Background</p> <p>Pancreatic ductal adenocarcinoma is a lethal disease with a 5-year survival rate of 4% and typically presents in an advanced stage. In this setting, prognostic markers identifying the more agrressive tumors could aid in managment decisions. Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3, also known as IMP3 or KOC) is an oncofetal RNA-binding protein that regulates targets such as insulin-like growth factor-2 (IGF-2) and ACTB (beta-actin).</p> <p>Methods</p> <p>We evaluated the expression of IGF2BP3 by immunohistochemistry using a tissue microarray of 127 pancreatic ductal adenocarcinomas with tumor grade 1, 2 and 3 according to WHO criteria, and the prognostic value of IGF2BP3 expression.</p> <p>Results</p> <p>IGF2BP3 was found to be selectively overexpressed in pancreatic ductal adenocarcinoma tissues but not in benign pancreatic tissues. Nine (38%) patient samples of tumor grade 1 (n = 24) and 27 (44%) of tumor grade 2 (n = 61) showed expression of IGF2BP3. The highest rate of expression was seen in poorly differentiated specimen (grade 3, n = 42) with 26 (62%) positive samples. Overall survival was found to be significantly shorter in patients with IGF2BP3 expressing tumors (P = 0.024; RR 2.3, 95% CI 1.2-4.8).</p> <p>Conclusions</p> <p>Our data suggest that IGF2BP3 overexpression identifies a subset of pancreatic ductal adenocarcinomas with an extremely poor outcome and supports the rationale for developing therapies to target the IGF pathway in this cancer.</p

    Mast Cells and Gastrointestinal Dysmotility in the Cystic Fibrosis Mouse

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    BACKGROUND: Cystic fibrosis (CF) has many effects on the gastrointestinal tract and a common problem in this disease is poor nutrition. In the CF mouse there is an innate immune response with a large influx of mast cells into the muscularis externa of the small intestine and gastrointestinal dysmotility. The aim of this study was to evaluate the potential role of mast cells in gastrointestinal dysmotility using the CF mouse (Cftr(tm1UNC), Cftr knockout). METHODOLOGY: Wild type (WT) and CF mice were treated for 3 weeks with mast cell stabilizing drugs (ketotifen, cromolyn, doxantrazole) or were treated acutely with a mast cell activator (compound 48/80). Gastrointestinal transit was measured using gavage of a fluorescent tracer. RESULTS: In CF mice gastric emptying at 20 min post-gavage did not differ from WT, but was significantly less than in WT at 90 min post-gavage. Gastric emptying was significantly increased in WT mice by doxantrazole, but none of the mast cell stabilizers had any significant effect on gastric emptying in CF mice. Mast cell activation significantly enhanced gastric emptying in WT mice but not in CF mice. Small intestinal transit was significantly less in CF mice as compared to WT. Of the mast cell stabilizers, only doxantrazole significantly affected small intestinal transit in WT mice and none had any effect in CF mice. Mast cell activation resulted in a small but significant increase in small intestinal transit in CF mice but not WT mice. CONCLUSIONS: The results indicate that mast cells are not involved in gastrointestinal dysmotility but their activation can stimulate small intestinal transit in cystic fibrosis

    Developing a collaborative agenda for humanities and social scientific research on laboratory animal science and welfare.

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    Improving laboratory animal science and welfare requires both new scientific research and insights from enquiry in the humanities and social sciences. Whilst scientific research provides evidence to replace, reduce and refine procedures involving laboratory animals (the ‘3Rs’), work in the humanities and social sciences can help understand the social, economic and cultural processes that enhance or impede humane ways of knowing and working with laboratory animals. However, communication across these disciplinary perspectives is currently limited, and they frame questions, generate results, engage users, and seek to influence policy in different ways. To facilitate dialogue and future research at this interface, we convened an interdisciplinary group of 45 life scientists, social scientists, humanities scholars, non-governmental organisations and policy-makers to generate a collaborative research agenda. This drew on other agenda-setting exercises in science policy, using a collaborative and deliberative approach for the identification of research priorities. Participants were recruited from across the community, invited to submit research questions and vote on their priorities. They then met at an interactive workshop in the UK, discussed all 136 questions submitted, and collectively defined the 30 most important issues for the group. The output is a collaborative future agenda for research in the humanities and social sciences on laboratory animal science and welfare. The questions indicate a demand for new research in the humanities and social sciences to inform emerging discussions and priorities on the governance and practice of laboratory animal research, including around: international harmonisation, openness and public engagement, ‘cultures of care’, harm-benefit analysis and the future of the 3Rs. The process underlines the value of interdisciplinary exchange for improving mutual understanding of different research cultures and identifies ways of enhancing the effectiveness of future research at the interface between the humanities, social sciences, science and science policy

    Inactivation of class II PI3K-C2 alpha induces leptin resistance, age-dependent insulin resistance and obesity in male mice

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    AIMS/HYPOTHESIS: While the class I phosphoinositide 3-kinases (PI3Ks) are well-documented positive regulators of metabolism, the involvement of class II PI3K isoforms (PI3K-C2α, -C2β and -C2γ) in metabolic regulation is just emerging. Organismal inactivation of PI3K-C2β increases insulin signalling and sensitivity, whereas PI3K-C2γ inactivation has a negative metabolic impact. In contrast, the role of PI3K-C2α in organismal metabolism remains unexplored. In this study, we investigated whether kinase inactivation of PI3K-C2α affects glucose metabolism in mice. METHODS: We have generated and characterised a mouse line with a constitutive inactivating knock-in (KI) mutation in the kinase domain of the gene encoding PI3K-C2α (Pik3c2a). RESULTS: While homozygosity for kinase-dead PI3K-C2α was embryonic lethal, heterozygous PI3K-C2α KI mice were viable and fertile, with no significant histopathological findings. However, male heterozygous mice showed early onset leptin resistance, with a defect in leptin signalling in the hypothalamus, correlating with a mild, age-dependent obesity, insulin resistance and glucose intolerance. Insulin signalling was unaffected in insulin target tissues of PI3K-C2α KI mice, in contrast to previous reports in which downregulation of PI3K-C2α in cell lines was shown to dampen insulin signalling. Interestingly, no metabolic phenotypes were detected in female PI3K-C2α KI mice at any age. CONCLUSIONS/INTERPRETATION: Our data uncover a sex-dependent role for PI3K-C2α in the modulation of hypothalamic leptin action and systemic glucose homeostasis. ACCESS TO RESEARCH MATERIALS: All reagents are available upon request

    Communications and Transport: The mobility of information, people and commodities

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    In a context where the study of communications tends to focus only on the mobility of information, to the neglect of that of people and commodities, this article explores the potential for a closer integration between the fields of communications and transport studies. Against the presumption that the emergence of virtuality means that material geographies are no longer of consequence, the role of mediated ‘technologies of distance’ is considered here in the broader contexts of the construction (and regulation) of a variety of physical forms of mobility and the changing modes of articulation of the virtual and material worlds
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