2,014 research outputs found
Role of intersticial cells of Cajal in the pacemaker activity and neurotransmission in the rat colon
No full textConsultable des del TDXTítol obtingut de la portada digitalitzadaEls objectius d'aquesta tesi han estat l'estudi de la funció de les cèl·lules intersticials de Cajal (ICCs) en l'activitat marcapassos i en la transmissió neuromuscular, dins el tracte gastrointestinal. L'estudi s'ha realitzat en el còlon perquè en aquesta part del tracte gastrointestinal els mecanismes marcapassos i de neurotransmissió són poc coneguts. El model de rata s'ha utilitzat perquè estudis previs, realitzats al nostre laboratori, van mostrar-hi un marcapassos d'origen miogènic, també descrit en el còlon humà. A més a més, les rates Ws/Ws tenen una mutació en el gen c-kit i presenten una afectació de certes línies cel·lulars, incloses les ICCs. Per tant, hem utilitzat tres grups d'animals: rates Sprague-Dawley, mutants Ws/Ws i les seves germanes controls +/+. Per investigar l'activitat marcapassos i la neurotransmissió vam realitzar: (i) tincions immunohistoquímiques amb anticossos c-kit i nNOS per marcar ICCs i neurones nitrèrgiques, respectivament; (ii) experiments d'activitat mecànica en bany d'òrgans; (iii) enregistraments elèctrics amb la tècnica de microelèctrodes intracel·lulars. Els nostres estudis mostren dues xarxes d'ICCs en el còlon de rata, a nivell dels plexes d'Auerbach (ICC-AP, 100 cèl·lules/mm2) i submuscular (ICC-SMP, 50-60 cèl·lules/mm2). Les ICCs intramurals (ICC-IM) van trobar-se distribuïdes de forma paral·lela entre les cèl·lules musculars llises. Resultats similars van ser obtinguts en rates Sprague-Dawley i +/+. En canvi, les rates mutants Ws/Ws van presentar una marcada disminució d'immunoreactivitat al c-kit. Les rates Sprague-Dawley van presentar una activitat elèctrica espontània formada per ones lentes i despolaritzacions cícliques, seguint un patró regular. Aquesta activitat elèctrica dóna lloc a contraccions d'alta i baixa freqüència, respectivament. Les contraccions d'alta i baixa freqüència varien en relació a l'orientació de la tira de múscul (orientació circular o longitudinal) i també en relació al segment estudiat (còlon proximal, mig i distal). L'activitat elèctrica i mecànica de les rates +/+ va ser similar a la presentada per les rates Sprague-Dawley. Les rates Ws/Ws, en canvi, van mostrar una alteració dels patrons mecànic i elèctric, presentant potencials d'acció irregulars que donaven lloc a contraccions incoordinades. La neurotransmissió va ser estudiada mitjançant: i) la distribució i quantificació de les neurones nNOS; ii) el potencial post unió inhibitori (IJP) i la relaxació mecànica induïda per l'estimulació elèctrica de camp; iii) la presència d'un to neural. Les neurones nNOS positives es van trobar a la regió del plexe d'Auerbach formant una xarxa de ganglis i branques, acompanyades per fibres primes que van trobar-se paral·leles a les cèl·lules llises musculars ( en major nombre en la capa muscular circular). El còlon mig va ser la zona més inervada (130 cèl·lules/mm2). En les rates Ws/Ws, es va observar una lleugera reducció en el nombre de neurones nitrèrgiques. Tant en rates Sprague-Dawley, com Ws/Ws i +/+, l'estimulació elèctrica de camp va causar un IJP i relaxació mecànica, degut a l'alliberació d'ATP i NO. A més a més, es va evidenciar un to neural funcional (inhibitori), provocat per l'alliberació tònica d'ATP i NO. Per tant, podem concloure que: (i) la presència de dues xarxes d'ICCs és un element indispensable per la correcta funció marcapassos en el còlon; (ii) les ICC-SMP serien responsables de les ones lentes de les quals s'originen les contraccions d'alta freqüència; (iii) les ICC-AP serien l'origen de les despolaritzacions cícliques que provoquen les contraccions de baixa freqüència; (iv) les propietats mecàniques de cada tira serien les responsables dels patrons motors que asseguren el trànsit, propulsió i barreja.; i finalment (v) les ICCs c-kit positives són elements no essencials per la neurotransmissió a no ser que aquesta funció la pogués acomplir les cèl·lules intersticials c-kit negatives o bé que es produís un canvi del fenotip en les rates mutants Ws/Ws.The objective of this research project was to investigate the role of interstitial cells of Cajal (ICCs) as pacemaker cells and as mediators of neuromuscular transmission in the gastrointestinal tract. We have studied the rat colon because in this part of the gastrointestinal tract the pacemaker and neurotransmission mechanisms are poorly understood. The rat is used as the animal model because previous work from our laboratory showed that a myogenic pacemaker is present, similarly to what it has been described in the human colon. Moreover, rats with a mutation in the c-kit gene show impairment of the development of certain classes of cell lineages, including ICCs. Accordingly, we have used three groups of animals: (i) Sprague-Dawley; (ii) Ws/Ws mutant rats and (iii) +/+ rats (the siblings of Ws/Ws mutant rats). To study the pacemaker activity and neurotransmission we have performed: (i) immunohistochemical stainings with c-kit and neuronal nitric oxide synthase (nNOS) antibodies to label ICCs and nitrergic neurons respectively; (ii) mechanical experiments with muscle bath technique and (iii) intracellular electrical recordings with microelectrode technique. Our results demonstrate that ICCs are present in the rat colon forming two networks at the level of the Auerbach's (ICC-AP, around 100 cells/mm2) and submuscular plexuses (ICC-SMP, about 50-60 cells/mm2). Intramural ICCs (ICC-IM) were found running parallel and between smooth muscle cells. Similar results were obtained both in Sprague-Dawley and +/+ rats. In contrast, a strong reduction in c-kit immunoreactivity was found in Ws/Ws rats. The spontaneous electrical activity in Sprague-Dawley rats consisted of slow waves superimposed with cyclic depolarizations forming a regular pattern. These two electrical events were responsible for high frequency (HF) and low frequency (LF) contractions, respectively. HF and LF contractions varied in relation to the orientation of the muscle strip (circular or longitudinal orientation) and the segment studied (proximal, mid and distal colon). The electrical and mechanical activities found in +/+ rats were very similar to those described in Sprague-Dawley rats. In contrast, Ws/Ws rats showed an impairment of the electrical and mechanical patterns, characterized by irregular action potentials, which cause uncoordinated contractions. Neurotransmission was studied with by: (i) the distribution and quantification of nNOS positive neurons; (ii) the inhibitory junction potential (IJP) and mechanical relaxation induced by electrical field stimulation and (iii) the presence of a neural tone. nNOS positive neurons were found at the Auerbach's plexus (AP) region forming a network of nerve strands and ganglia. Moreover, fine fibers were found running parallel to smooth muscle cells, especially in the circular muscle layer. The mid colon was the most innervated segment (about 130 cells/mm2). A slight reduction in nNOS positive neurons was observed in Ws/Ws rats compared to control rats. Electrical field stimulation caused an IJP and mechanical relaxation due to the release of ATP and NO. Moreover, a functional neural tone due to the ongoing release of ATP and NO was present. These results were observed in the three groups of animals: Sprague-Dawley, +/+ and Ws/Ws rats. We conclude that: (i) the presence of two ICC networks is a crucial element responsible for the pacemaker activity in the colon; (ii) the ICC-SMP network is probably responsible for the slow wave activity that originates HF contractions; (iii) the ICC-AP network might be responsible for the cyclic depolarizations that trigger LF contractions; (iv) the mechanical properties of each strip are responsible for the motor events that ensure transit, propulsion and mixing and (v) c-kit positive ICC cells are not essential elements for neurotransmission, unless this function could be accomplished by c-kit negative interstitial cells or alternatively, a change in the phenotype of Ws/Ws animals occurs
VCC-LF dataset
No full textThis is readme for VCC-LF dataset.
This dataset provides light field mat files that capture by Lytro I.
The light field resolusion is [h,w,u,v,d].
If you use these data or our toolkit code, please cite our paper properly
@inproceedings{ lirsiggraphasia2019,
title={Hierarchical and View-invariant Light Field Segmentation by Maximizing Entropy Rate on 4D Ray Graphs},
author={Li, Rui and Heidrich, Wolfgang},
booktitle={ACM Transactions on Graphics (Proc. SIGGRAPH Asia)},
year={2019},
publisher={ACM}
White light and EGFP imaging of intestine in CONV NF-κB<sup>EGFP</sup> mice on HF/LF diet.
No full text<p>White arrow: autofluorescence which is common in proximal colon. A: 2 weeks on HF/LF diet. B: 6 weeks on HF/LF diet. C: >16 weeks on HF/LF diet. Abbreviations: Duo: duodenum; Jej:Jejunum; Ile: ileum; Col:colon.</p
LF-copying without LF
No full textAbstractA copying approach to ellipsis is presented, whereby the locus of copying is not a level of derived syntactic structure (LF), but rather the derivation itself. The ban on preposition stranding in sprouting follows without further stipulation, and other, seemingly structure sensitive, empirical generalizations about elliptical constructions, including the preposition stranding generalization, follow naturally as well. Destructive operations which ‘repair’ non-identical antecedents are recast in terms of exact identity of derivations with parameters. In the context of a compositional semantic interpretation scheme, the derivational copying approach to ellipsis presented here is revealed to be a particular instance of a proform theory, thus showing that the distinctions between, and arguments about, syntactic and semantic theories of ellipsis need to be revisited
Lactoferrin Inhibits the Development of T2D-Induced Colon Tumors by Regulating the NT5DC3/PI3K/AKT/mTOR Signaling Pathway
No full textAlthough increasing evidence shows the association between type 2 diabetes (T2D) and colorectal cancer, the related mechanism remains unclear. This study examined the suppressive effect of lactoferrin (LF) on the development of T2D-induced colon cancer. First, a co-cultured cell model consisting of NCM460 and HT29 cells was constructed to mimic the progression of T2D into colon cancer. The migration ability of NCM460 cells increased significantly (p < 0.05) after cultivation in HT29 cell medium (high glucose), while LF suppressed the progression of T2D to colon cancer by regulating the 5′-nucleotidase domain-containing 3 (NT5DC3) protein and the PI3K/AKT/mTOR signaling pathway in diabetic BALB/c mice and in cell models. A mutation assay of the phosphorylation site in the NT5DC3 protein and a surface plasmon resonance (SPR) protein binding test were performed to further ascertain a mechanistic link between LF and the NT5DC3 protein. The results indicated that LF specifically bound to the NT5DC3 protein to activate its phosphorylation at the Thr6 and Ser11 sites. Next, metabolic-specific staining and localization experiments further confirmed that LF acted as a phosphate donor for NT5DC3 protein phosphorylation by regulating the downstream metabolic pathway in T2D-induced colon tumors, which was specifically accomplished by controlling Thr6/Ser11 phosphorylation in NT5DC3 and its downstream effectors. These data on LF and NT5DC3 protein may suggest a new therapeutic strategy for cancer prevention, especially in T2D patients susceptible to colon cancer
Crohn's disease activity index and Vienna classification - Is it worthwhile to calculate before surgery?
No full textBackground: Crohn's disease (CD) patients with increased disease activity may reveal an increased risk for perioperative complications. The `Crohn's disease activity index' (CDAI) and the `Vienna classification' (VC) were developed for standardized disease activity estimations. The significance of these scores to predict extent, type and early outcome of surgery in CD patients was analyzed. Methods: In 179 surgically treated CD patients, the CDAI and VC were assessed from a prospective database. Relations of the scores with CD risk factors, type, number, location and complications of surgery were analyzed. Results: VC behavior and location subtypes were associated with distinct types of surgery (i.e. `strictureplasty' in `stricturing disease', `colon surgery' in `colon involvement'), but not with surgery type and extent or outcome. Surgery extent (i.e. with 5 vs. 3 `surgical sites' 425 +/- 25 vs. 223.3 +/- 25) and complications (357.1 +/- 36.9 (with) vs. 244.4 +/- 13 (without)) were associated with elevated CDAI levels; however, nicotine abuse remained the only significant risk factor for perioperative complications after multiple logistic regression. Conclusion: The significance of VC or CDAI for predicting the extent of surgery or complications is limited. None of the tested variables except preoperative nicotine abuse influenced the likelihood for perioperative complications. Copyright (c) 2006 S. Karger AG, Base
Validation of q-PCR for quantitation of LF and effect of LF41 administration on LF-specific 16S rRNA levels in intestinal tissues.
No full text<p><b>(A)</b> LF41, BC41, or LGG was cultured in MRS broth at 37°C overnight. An aliquot of culture from each culture was dilution-plated on MRS agar (to enumerate each strain). Total bacterial genomic DNA was isolated from an aliquot of each culture and analyzed by q-PCR using the primers specific to the 16S rRNA of either LF or LGG. Black and white triangles denote log numbers of 16S rRNA gene copies determined by LF- and LGG-specific q-PCR, respectively; black squares denote log numbers of bacteria determined by serial dilution. <b>(B)</b> MRS broth was co-inoculated with LGG and low, middle, or high dose of LF41, grown at 37°C overnight. Total bacterial genomic DNA was isolated from an aliquot of each sample and analyzed by q-PCR using the primers specific to 16S rRNA of <i>Lactobacillus</i>, LF, or LGG. The samples of a, b, and c denote the co-cultures of LGG with low, middle, and high dose of LF41, respectively; “R(LF)” and “R(LGG)” denote the ratios of the respective 16S rRNA gene copies determined by LF- and LGG-specific q-PCR to the gene copies by <i>Lactobacillus</i>-specific q-PCR. <b>(B)(C)(D)</b> Mice (n = 8) were orally inoculated either for 10 days with PBS, L-LF41, or H-LF41, or for 3 weeks with PBS or H-LF41, and LF-specific 16S rRNA gene levels in terminal ileum <b>(B)</b>, proximal colon <b>(C)</b>, and distal jejuna <b>(D)</b> determined by q-PCR. Results are expressed as log<sub>10</sub> of the 16S rRNA gene copies per mg of tissue samples. Values of are shown as mean ± SEM. * P < 0.05 compared to L-LF41 or H-LF41 (21 days); <b>+</b> P < 0.05 compared to H-LF41 (10 days); nd, not detected. Results are representative of 2 experiments with similar results.</p
Motility patterns and distribution of interstitial cells of Cajal and nitrergic neurons in the proximal, mid- and distal-colon of the rat
No full textUdgivelsesdato: 2005-FebThe aim of this work was to study the patterns of spontaneous motility in the circular and longitudinal muscle strips and to characterize the distribution of c-kit positive interstitial cells of Cajal (ICCs) and nitrergic neurons (nNOS) in the proximal, mid- and distal-colon of Sprague-Dawley rats. We described two types of spontaneous contractions: high frequency (HF) and low frequency (LF) contractions, which were recorded in the presence of tetrodotoxin, suggesting a non-neurogenic origin. Regional differences were found in the motility patterns depending on the muscle layer and on the part of the colon studied. Muscle strips without submuscular plexus (SMP) showed only LF contractions. The density of ICCs was of the same magnitude along the extent of the colon: about 90-120 cells mm(-2) at Auerbach's plexus (AP) and 50-60 cells mm(-2) at the SMP. nNOS positive cells were found at the level of the AP and the major density was found in the mid-colon. Electrical field stimulation abolished LF but did not affect HF contractions. Our results indicate that HF contractions are due to the ICC network found associated with the submuscular plexus (ICC-SMP). The origin of LF contractions is still unknown
Polynomial Approximation in Ep(D) with 0 < p < 1
No full textAbstractIn this paper, we construct approximants by means of interpolation polynomialsto prove Jackson′s theorem and the Bernstein inequality in Ep(D) with 0 < p < 1
Mean Convergence of Interpolation Polynomials in a Domain with Corners
No full textAbstractIn this paper, we prove mean convergence of interpolation polynomials in a domain with some corners
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