Helicobacter pullorum cytolethal distending toxin targets vinculin and cortactin and triggers formation of lamellipodia in intestinal epithelial cells

Helicobacter pullorum, a bacterium initially isolated from poultry, has been associated with human digestive disorders. However, the factor responsible for its cytopathogenic effects on epithelial cells has not been formally identified. The cytopathogenic alterations induced by several human and avian H. pullorum strains were investigated on human intestinal epithelial cell lines. Moreover, the effects of the cytolethal distending toxin (CDT) were evaluated first by using a wild-type strain and its corresponding cdtB isogenic mutant and second by delivering the active CdtB subunit of the CDT directly into the cells. All of the H. pullorum strains induced cellular distending phenotype, actin cytoskeleton remodeling, and G2/M cell cycle arrest. These effects were dependent on the CDT, as they were (1) not observed in response to a cdtB isogenic mutant strain and (2) present in cells expressing CdtB. CdtB also induced an atypical delocalization of vinculin from focal adhesions to the perinuclear region, formation of cortical actin-rich large lamellipodia with an upregulation of cortactin, and decreased cellular adherence. In conclusion, the CDT of H. pullorum is responsible for major cytopathogenic effects in vitro, confirming its role as a main virulence factor of this emerging human pathogen.This work was supported by the Institut national de la santé et de la recherche médicale, the University Bordeaux Segalen, the Conseil Régional d’Aquitaine (grants 20030304002FA and 20040305003 FA), the Société Nationale Française de Gastroentérologie, the European Union (FEDER no. 2003227

Systems and technologies for objective evaluation of technical skills in laparoscopic surgery

Minimally invasive surgery is a highly demanding surgical approach regarding technical requirements for the surgeon, who must be trained in order to perform a safe surgical intervention. Traditional surgical education in minimally invasive surgery is commonly based on subjective criteria to quantify and evaluate surgical abilities, which could be potentially unsafe for the patient. Authors, surgeons and associations are increasingly demanding the development of more objective assessment tools that can accredit surgeons as technically competent. This paper describes the state of the art in objective assessment methods of surgical skills. It gives an overview on assessment systems based on structured checklists and rating scales, surgical simulators, and instrument motion analysis. As a future work, an objective and automatic assessment method of surgical skills should be standardized as a means towards proficiency-based curricula for training in laparoscopic surgery and its certification

Introduction to the mathematical theory of knowledge conceptualization: Conceptual systems and structures

The paper departs from the general problem of knowledge integration and the basic strategies that can be adopted to confront this challenge. With the purpose of providing a sound meta-theoretical framework to facilitate knowledge conceptualization and integration, as well as assessment criteria to evaluate achievements regarding knowledge integration, the paper first reviews the previous work in the field of conceptual spaces. It subsequently gives an overview of structural tools and mechanisms for knowledge representation, recapped in the modal stratified bond model of global knowledge. On these groundings, a novel formalized representation of conceptual systems, structures, spaces and algebras is developed through a set of definitions which goes beyond the exploration of mental knowledge representation and the semantics of natural languages. These two components provide a sound framework for the development of the glossaLAB international project with respect to its two basic objectives, namely (i) facilitating knowledge integration in general and particularly in the context of the general study of information and systems; (ii) facilitating the assessment of the achievements as regards knowledge integration in interdisciplinary settings. An additional article tackles the solutions adopted to integrate these results in the elucidation of the conceptual network of the general study of information and systems.2019-2

Integer Programs with Prescribed Number of Solutions and a Weighted Version of Doignon-Bell-Scarf’s Theorem

peer reviewedIn this paper we study a generalization of the classical fesibility problem in integer linear programming, where an ILP needs to have a prescribed number of solutions to be considered solved. We first provide a generalization of the famous Doignon-Bell-Scarf theorem: Given an integer k, we prove that there exists a constant c(k, n), depending only on the dimension n and k, such that if a polyhedron {x : Ax ≤ b} contains exactly k integer solutions, then there exists a subset of the rows of cardinality no more than c(k,n), defining a polyhedron that contains exactly the same k integer solutions. The second contribution of the article presents a structure theory that characterizes precisely the set Sg≥k (A) of all vectors b such that the problem Ax = b, x ≥ 0, x ∈ Zn , has at least k-solutions. We demonstrate that this set is finitely generated, a union of translated copies of a semigroup which can be computed explicitly via Hilbert bases computation. Similar results can be derived for those right-hand-side vectors that have exactly k solutions or fewer than k solutions. Finally we show that, when n, k are fixed natural numbers, one can compute in polynomial time an encoding of Sg≥k(A) as a generating function, using a short sum of rational functions. As a consequence, one can identify all right-hand-side vectors that have exactly k solutions (similarly for at least k or less than k solutions). Under the same assumptions we prove that the k-Frobenius number can be computed in polynomial time

Seasonal release of the egg capsules of <i>Anoplodium parasita</i> Schneider, 1858, intracoelomic turbellarian (Platyhelminthes, Rhabdocoela) symbiotic of the sea cucumber <i>Holothuria tubulosa</i> Gmelin, 1788 (Echinodermata, Holothuroida)

The endosymbiotic umagillid Anoplodium parasita Schneider, 1858 (Platyhelminthes, Rhabdocoela) lives in the perivisceral coelom of the sea cucumber Holothuria tubulosa Gmelin, 1788 (Echinodermata, Holothuroida). The flatworms release their egg capsules in the coelomic cavity of their host, where they are embedded in brown bodies concentrated in the posterior part of the body, near the cloaca. The infestation of the holothurians by turbellarian egg capsules was very high: 128 out of the 202 holothurians inspected from January 1999 to July 2000 at Banyuls-sur-mer (France) contained at least 6 and up to 10,000 egg capsules (mean 1433). Quite uniform throughout the year, the number of holothuroids infested as well as the number of egg capsules found per individual drastically fall in July, the period when the gonads of holothurians are highly developed. We suggest that the release of egg capsules might be an indirect result of the spawning of the hosts. To discharge their gametes, holothurians raise their body and adhere on the substratum by their posterior end. This behaviour would cause a surpressure in the peri-cloacal coelomic area of the holothurians and consequently the expulsion of the coelomic fluids through their coelo-cloacal ducts, carrying brown bodies and egg capsules to the outside

Seasonal release of the egg capsules of Anoplodium parasita Schneider, 1858, intracoelomic turbellarian (Platyhelminthes, Rhabdocoela) symbiotic of the sea cucumber Holothuria tubulosa Gmelin, 1788 (Echinodermata, Holothuroida)

info:eu-repo/semantics/publishe

Distribution of 11 beta-hydroxysteroid dehydrogenase along the rabbit nephron.

It has been recently proposed that 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) is responsible for aldosterone tissue specificity. A 11 beta-OHSD deficiency has been invoked as a cause of the syndrome of apparent mineralocorticoid excess, and 11 beta-OHSD inhibition by liquorice has been invoked to explain the hypertension induced by this drug. Since the renal tubule is composed of aldosterone-sensitive and insensitive segments, we determined the distribution of 11 beta-OHSD along the rabbit tubule. Pools of tubular segments isolated by microdissection were incubated for 2 h at 37 degrees C in the presence of [3H]corticosterone (3H-B, 8.10(-9) M). Afterwards, the amounts of 3H-B and of the metabolite 11-dehydrocorticosterone (3H-A) were determined using HPLC analysis. In the proximal tubule, in either its convoluted or straight portion, and in the medullary thick ascending limb, the amount of 3H-A was 19.6 +/- 3.8% (n = 12), 17.9 +/- 3.4 (n = 8), and 15.0 +/- 2.2 (n = 4), respectively, of the sum of 3H-A + 3H-B. In the cortical ascending limb and the collecting tubule in its cortical and medullary parts, it was 74.7 +/- 6.8% (n = 4), 74.1 +/- 4.9 (n = 9) and 64.6 +/- 14.1 (n = 3), respectively. In both proximal and cortical collecting tubule, addition of carbenoxolone 8.10(-4) M, an inhibitor of 11 beta-OHSD, almost completely inhibited the conversion of 3H-B to 3H-A. Thus, 11 beta-OHSD activity was high in the aldosterone-sensitive segments, and low in the aldosterone-insensitive segments. These results strongly favor the hypothesis that 11 beta-OHSD is a key enzyme in mineralocorticoid tissue specificity along the rabbit nephron. They reinforce the notion that a defect in 11 beta-OHSD plays a major role in the syndrome of apparent mineralocorticoid excess and liquorice-induced hypertension