5,121 research outputs found
Human Pancreatic Acinar Cells Do Not Respond to Cholecystokinin
Pancreatic secretion can be influenced by cholecystokinin (CCK) either directly via actions on acinar cells or indirectly via actions on nerves. The presence and functional roles of CCK receptors on human pancreatic acinar cells remains unclear. In the current study human pancreatic acini were isolated and then treated with CCK-8, gastrin and/or carbachol. Functional parameters were measured including intracellular [Ca2+] and amylase secretion. It was observed that human acini did not respond to CCK agonists but did respond to carbachol with robust increases in functional parameters. Adenoviral-mediated gene transfer of CCK1 or CCK2 receptors to the human cells resulted in cell responses to CCK agonists. In order to determine the reason for the lack of responsiveness of the human acini, expression of receptor mRNAs was determined using quantitative RT-PCR and localized by in situ hybridization. mRNA levels for CCK1 receptors were ∼30 times lower than those of CCK2 receptors, which were ∼10 times lower than those of m3 Ach receptors as measured by quantitative PCR. Neither CCK1 nor CCK2 receptors were localized in adult human pancreas by i n situ hybridization. These results indicate that human pancreatic acinar cells do not respond directly to CCK receptor activation and this is likely due to an insufficient level of receptor expression.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73903/1/j.1600-0773.2002.910610.x.pd
Chronic activation of Toll-like receptor 2 induces an ichthyotic skin phenotype.
BACKGROUND: Ichthyosis defines a group of chronic conditions that manifest phenotypically as a thick layer of scales and often affects the entire skin. While the gene mutations that lead to ichthyosis are well documented, the actual signalling mechanisms that lead to scaling are poorly characterised, however recent publications suggest that there are common mechanisms active in ichthyotic tissue, and in analogous models of ichthyosis. OBJECTIVE: To determine common mechanisms of hyperkeratosis that may be easily targeted with small molecule inhibitors. METHODS: We combined gene expression analysis of gene-specific shRNA knockdowns in rat epidermal keratinocytes of two genes mutated in autosomal recessive congenital ichthyosis (ARCI), Transglutaminase 1 (TGM1) and arachidonate 12-lipoxygenase, 12R type (ALOX12B), and proteomic analysis of skin scale from ARCI patients.as well as RNAseq data from rat epidermal keratinocytes treated with the Toll-like receptor-2 agonist PAM3CSK. RESULTS: we identified a common activation of the Toll-like receptor (TLR) 2 pathway. Exogenous TLR2 activation led to increased expression of important cornified envelope genes and in organotypic culture caused hyperkeratosis. Conversely, blockade of TLR2 signalling in ichthyosis patient keratinocytes and our shRNA models reduced the expression of keratin 1, a structural protein over-expressed in ichthyosis scale. A time-course of Tlr2 activation in rat epidermal keratinocytes revealed that although there was rapid initial activation of innate immune pathways, this was rapidly superseded by widespread up-regulation of epidermal differentiation related proteins. Both NFκβ phosphorylation and Gata3 up-regulation was associated with this switch and Gata3 overexpression was sufficient to increase Keratin 1 expression. CONCLUSION: Taken together, these data define a dual role for Toll-like receptor 2 activation during epidermal barrier repair, that may be a useful therapeutic modality in treating diseases of epidermal barrier dysfunction
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Who, What, When, Where, Why? Comparing Multiple Approaches to the Cross-Lingual 5W Task
Cross-lingual tasks are especially difficult due to the compounding effect of errors in language processing and errors in machine translation (MT). In this paper, we present an error analysis of a new cross-lingual task: the 5W task, a sentence-level understanding task which seeks to return the English 5W's (Who, What, When, Where and Why) corresponding to a Chinese sentence. We analyze systems that we developed, identifying specific problems in language processing and MT that cause errors. The best cross-lingual 5W system was still 19% worse than the best monolingual 5W system, which shows that MT significantly degrades sentence-level understanding. Neither source-language nor target-language analysis was able to circumvent problems in MT, although each approach had advantages relative to the other. A detailed error analysis across multiple systems suggests directions for future research on the problem
A giant stem-group chaetognath
Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, Timorebestia koprii gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to Amiskwia sagittiformis. Amiskwia has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that T. koprii shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in T. koprii suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today
A giant stem-group chaetognath.
Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to . has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today
Mesothelial Cyst of the Round Ligament Mimicking a Metastasis: a Case Report
A mesothelial cyst of the round ligament is a rare cause of an inguinal mass. Clinically, it is frequently misdiagnosed as one of commoner diseases such as an inguinal hernia, femoral hernia, lipoma, and lymphadenopathy upon physical examination. Some previous reports elaborated the sonographic features of a mesothelial cyst of the round ligament. However, to our knowledge, few reports have described the CT features of a mesothelial cyst. We illustrated here the sonographic and multidetector CT features of a case of a mesothelial cyst of the round ligament that presented as an inguinal palpable mass and mimicked a metastasis in a patient with a Sertoli-Leydig cell tumor of the ovary
Stellar winds from Massive Stars
We review the various techniques through which wind properties of massive
stars - O stars, AB supergiants, Luminous Blue Variables (LBVs), Wolf-Rayet
(WR) stars and cool supergiants - are derived. The wind momentum-luminosity
relation (e.g. Kudritzki et al. 1999) provides a method of predicting mass-loss
rates of O stars and blue supergiants which is superior to previous
parameterizations. Assuming the theoretical sqrt(Z) metallicity dependence,
Magellanic Cloud O star mass-loss rates are typically matched to within a
factor of two for various calibrations. Stellar winds from LBVs are typically
denser and slower than equivalent B supergiants, with exceptional mass-loss
rates during giant eruptions Mdot=10^-3 .. 10^-1 Mo/yr (Drissen et al. 2001).
Recent mass-loss rates for Galactic WR stars indicate a downward revision of
2-4 relative to previous calibrations due to clumping (e.g. Schmutz 1997),
although evidence for a metallicity dependence remains inconclusive (Crowther
2000). Mass-loss properties of luminous (> 10^5 Lo) yellow and red supergiants
from alternative techniques remain highly contradictory. Recent Galactic and
LMC results for RSG reveal a large scatter such that typical mass-loss rates
lie in the range 10^-6 .. 10^-4 Mo/yr, with a few cases exhibiting 10^-3 Mo/yr.Comment: 16 pages, 2 figures, Review paper to appear in Proc `The influence of
binaries on stellar population studies', Brussels, Aug 2000 (D. Vanbeveren
ed.), Kluwe
Conceptual Challenges for Advancing the Socio-Technical Underpinnings of Health Informatics
This discussion paper considers the adoption of socio-technical perspectives and their theoretical and practical influence within the discipline of health informatics. The paper highlights the paucity of discussion of the philosophy, theory and concepts of socio-technical perspectives within health informatics. Instead of a solid theoretical base from which to describe, study and understand human-information technology interactions we continue to have fragmented, unelaborated understandings. This has resulted in a continuing focus on technical system performance and increasingly managerial outputs to the detriment of social and technical systems analysis. It has also limited critical analyses and the adaptation of socio-technical approaches beyond the immediate environment to the broader social systems of contemporary society, an expansion which is increasingly mandated in today’s complex health environment
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