101 resultados para proof-of-concept
Resumo:
Distal myopathies represent a heterogeneous group of inherited skeletal muscle disorders. One type of adult-onset, progressive autosomal-dominant distal myopathy, frequently associated with dysphagia and dysphonia (vocal cord and pharyngeal weakness with distal myopathy [VCPDM]), has been mapped to chromosome 5q31 in a North American pedigree. Here, we report the identification of a second large VCPDM family of Bulgarian descent and fine mapping of the critical interval. Sequencing of positional candidate genes revealed precisely the same nonconservative S85C missense mutation affecting an interspecies conserved residue in the MATR3 gene in both families. MATR3 is expressed in skeletal muscle and encodes matrin 3, a component of the nuclear matrix, which is a proteinaceous network that extends throughout the nucleus. Different disease related haplotype signatures in the two families provided evidence that two independent mutational events at the same position in MATR3 cause VCPDM. Our data establish proof of principle that the nuclear matrix is crucial for normal skeletal muscle structure and function and put VCPDM on the growing list of monogenic disorders associated with the nuclear proteome.
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Nuptial flight in Formica lugubris was studied within a super-colony located in the Swiss Jura. Sexuals (imago) were present in the nests during one month (June). The flight season was ea. 2-3 weeks. The presence of sexuals at nest surface as well as take-off were temperature-dependant, occuring above l0°C and l8°C, respectively. Length of daily flights, number of sexuals leaving the nest as well as number of sexuals produced were estimated. There was no proof of any circadian rhythm and no marked differences between males and females except in mixed nests where females did not fly and copulated at nest surface.
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PURPOSE OF REVIEW: Mycoplasma hominis and Ureaplasma urealyticum may colonize the human genital tract and have been associated with adverse pregnancy outcomes. Chorioamnionitis, spontaneous preterm labour and preterm premature rupture of membranes are significant contributors to neonatal morbidity and mortality. However, as these bacteria can reside in the normal vaginal flora, there are controversies regarding their true role during pregnancy and thus the need to treat these organisms. RECENT FINDINGS: We review here the recent data on the epidemiology of mycoplasmas and their clinical role during pregnancy. The association of these organisms with preterm labour has been suggested by many observational studies, but proof of causality remains limited. PCR is an excellent alternative to culture to detect the presence of these organisms, but culture allows antibiotic susceptibility testing. Whether antimicrobial treatment of mycoplasma-colonized pregnant patients can effectively reduce the incidence of adverse pregnancy outcomes warrants further investigations. SUMMARY: The role of Mycoplasma spp. and U. urealyticum in adverse pregnancy outcomes is increasingly accepted. However, sole presence of these microorganisms in the vaginal flora might be insufficient to cause pathological issues, but their combination with other factors such as bacterial vaginosis or cervical incompetence may be additionally needed to induce preterm birth.
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Since the development of the first whole-cell living biosensor or bioreporter about 15 years ago, construction and testing of new genetically modified microorganisms for environmental sensing and reporting has proceeded at an ever increasing rate. One and a half decades appear as a reasonable time span for a new technology to reach the maturity needed for application and commercial success. It seems, however, that the research into cellular biosensors is still mostly in a proof-of-principle or demonstration phase and not close to extensive or commercial use outside of academia. In this review, we consider the motivations for bioreporter developments and discuss the suitability of extant bioreporters for the proposed applications to stimulate complementary research and to help researchers to develop realistic objectives. This includes the identification of some popular misconceptions about the qualities and shortcomings of bioreporters.
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Validation is the main bottleneck preventing theadoption of many medical image processing algorithms inthe clinical practice. In the classical approach,a-posteriori analysis is performed based on someobjective metrics. In this work, a different approachbased on Petri Nets (PN) is proposed. The basic ideaconsists in predicting the accuracy that will result froma given processing based on the characterization of thesources of inaccuracy of the system. Here we propose aproof of concept in the scenario of a diffusion imaginganalysis pipeline. A PN is built after the detection ofthe possible sources of inaccuracy. By integrating thefirst qualitative insights based on the PN withquantitative measures, it is possible to optimize the PNitself, to predict the inaccuracy of the system in adifferent setting. Results show that the proposed modelprovides a good prediction performance and suggests theoptimal processing approach.
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An emerging therapeutic approach for Duchenne muscular dystrophy is the transplantation of autologous myogenic progenitor cells genetically modified to express dystrophin. The use of this approach is challenged by the difficulty in maintaining these cells ex vivo while keeping their myogenic potential, and ensuring sufficient transgene expression following their transplantation and myogenic differentiation in vivo. We investigated the use of the piggyBac transposon system to achieve stable gene expression when transferred to cultured mesoangioblasts and into murine muscles. Without selection, up to 8% of the mesoangioblasts expressed the transgene from 1 to 2 genomic copies of the piggyBac vector. Integration occurred mostly in intergenic genomic DNA and transgene expression was stable in vitro. Intramuscular transplantation of mouse Tibialis anterior muscles with mesoangioblasts containing the transposon led to sustained myofiber GFP expression in vivo. In contrast, the direct electroporation of the transposon-donor plasmids in the mouse Tibialis muscles in vivo did not lead to sustained transgene expression despite molecular evidence of piggyBac transposition in vivo. Together these findings provide a proof-of-principle that piggyBac transposon may be considered for mesoangioblast cell-based therapies of muscular dystrophies.
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CD8+ cytotoxic T lymphocyte (CTL) can recognize and kill target cells that express only a few cognate major histocompatibility complex class I-peptide (pMHC) complexes. To better understand the molecular basis of this sensitive recognition process, we studied dimeric pMHC complexes containing linkers of different lengths. Although dimers containing short (10-30-A) linkers efficiently bound to and triggered intracellular calcium mobilization and phosphorylation in cloned CTL, dimers containing long linkers (> or = 80 A) did not. Based on this and on fluorescence resonance energy transfer experiments, we describe a dimeric binding mode in which two T cell receptors engage in an anti-parallel fashion two pMHC complexes facing each other with their constant domains. This binding mode allows integration of diverse low affinity interactions, which increases the overall binding and, hence, the sensitivity of antigen recognition. In proof of this, we demonstrated that pMHC dimers containing one agonist and one null ligand efficiently activate CTL, corroborating the importance of endogenous pMHC complexes in antigen recognition.
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The treatment of stage IV melanoma has been revolutionized over the last years with the development of immunotherapies that, for the first time, have shown a significant benefit in overall survival, as well as with extremely effective targeted therapies, that also led to improved survival. These results are the fruits of an important translational research effort that allowed a rational approach with a very fast clinical development. The treatment of metastatic melanoma is, therefore, an illustration of the new paradigms of modern molecular research in oncology. In this review, we will present the various agents that have made the proof of their clinical benefit, as well as the scientific discoveries that allowed their development. Some of the remaining questions will be touched upon with the ongoing clinical trials. Inclusion of patients in these studies remains the top priority to improve on the clinical care.
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BACKGROUND: To evaluate feasibility and preliminary outcomes associated with sequential whole abdomen irradiation (WAI) as consolidative treatment following comprehensive surgery and systemic chemotherapy for advanced endometrial cancer. METHODS: We conducted a retrospective analysis of patients treated at our institution from 2000 to 2011. Inclusion criteria were stage III-IV endometrial cancer patients with histological proof of one or more sites of extra-uterine abdomen-confined disease, treated with WAI as part of multimodal therapy. Endpoints were feasibility, acute toxicity, late effects, recurrence-free survival (RFS) and overall survival (OS). Twenty patients were identified. Chemotherapy consisted of 3 to 6 cycles of a platinum-paclitaxel regimen in 18 patients. WAI was delivered using conventional technique to a median total dose of 27.5 Gy. RESULTS: No grade 4 toxicities occurred during chemotherapy or radiotherapy. No radiation dose reduction was necessary. Three patients developed small bowel obstruction, all in the context of recurrent intraperitoneal disease. Kaplan-Meier estimates and 95% confidence intervals for RFS and OS at one year were 63% (38-80%) and 83% (56-94%) and at 3 years 57% (33-76%) and 62% (34-81%), respectively. On univariate Cox analysis, stage IVB and serous papillary (SP) histology were found to be statistically significantly (at the p = 0.05 level) associated with worse RFS and OS. The peritoneal cavity was the most frequent site of initial failure. CONCLUSIONS: Consolidative WAI following chemotherapy is feasible and can be performed without interruption with manageable acute and late toxicity. Patients with endometrioid adenocarcinoma, especially stage FIGO III, had favorable outcomes possibly meriting prospective evaluation of the addition of WAI following chemotherapy in selected patients. Patients with SP do poorly and do not routinely benefit from this approach.
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This thesis deals with combinatorics, order theory and descriptive set theory. The first contribution is to the theory of well-quasi-orders (wqo) and better-quasi-orders (bqo). The main result is the proof of a conjecture made by Maurice Pouzet in 1978 his thèse d'état which states that any wqo whose ideal completion remainder is bqo is actually bqo. Our proof relies on new results with both a combinatorial and a topological flavour concerning maps from a front into a compact metric space. The second contribution is of a more applied nature and deals with topological spaces. We define a quasi-order on the subsets of every second countable To topological space in a way that generalises the Wadge quasi-order on the Baire space, while extending its nice properties to virtually all these topological spaces. The Wadge quasi-order of reducibility by continuous functions is wqo on Borei subsets of the Baire space, this quasi-order is however far less satisfactory for other important topological spaces such as the real line, as Hertling, Ikegami and Schlicht notably observed. Some authors have therefore studied reducibility with respect to some classes of discontinuous functions to remedy this situation. We propose instead to keep continuity but to weaken the notion of function to that of relation. Using the notion of admissible representation studied in Type-2 theory of effectivity, we define the quasi-order of reducibility by relatively continuous relations. We show that this quasi-order both refines the classical hierarchies of complexity and is wqo on the Borei subsets of virtually every second countable To space - including every (quasi-)Polish space. -- Cette thèse se situe dans les domaines de la combinatoire, de la théorie des ordres et de la théorie descriptive. La première contribution concerne la théorie des bons quasi-ordres (wqo) et des meilleurs quasi-ordres (bqo). Le résultat principal est la preuve d'une conjecture, énoncée par Pouzet en 1978 dans sa thèse d'état, qui établit que tout wqo dont l'ensemble des idéaux non principaux ordonnés par inclusion forme un bqo est alors lui-même un bqo. La preuve repose sur de nouveaux résultats, qui allient la combinatoire et la topologie, au sujet des fonctions d'un front vers un espace métrique compact. La seconde contribution de cette thèse traite de la complexité topologique dans le cadre des espaces To à base dénombrable. Dans le cas de l'espace de Baire, le quasi-ordre de Wadge est un wqo sur les sous-ensembles Boréliens qui a suscité énormément d'intérêt. Cependant cette relation de réduction par fonctions continues s'avère bien moins satisfaisante pour d'autres espaces d'importance tels que la droite réelle, comme l'ont fait notamment remarquer Hertling, Schlicht et Ikegami. Nous proposons de conserver la continuité et d'affaiblir la notion de fonction pour celle de relation. Pour ce faire, nous utilisons la notion de représentation admissible étudiée en « Type-2 theory of effectivity » initiée par Weihrauch. Nous introduisons alors le quasi-ordre de réduction par relations relativement continues et montrons que celui-ci à la fois raffine les hiérarchies classiques de complexité topologique et forme un wqo sur les sous-ensembles Boréliens de chaque espace quasi-Polonais.
Resumo:
Expression control in synthetic genetic circuitry, for example, for construction of sensitive biosensors, is hampered by the lack of DNA parts that maintain ultralow background yet achieve high output upon signal integration by the cells. Here, we demonstrate how placement of auxiliary transcription factor binding sites within a regulatable promoter context can yield an important gain in signal-to-noise output ratios from prokaryotic biosensor circuits. As a proof of principle, we use the arsenite-responsive ArsR repressor protein from Escherichia coli and its cognate operator. Additional ArsR operators placed downstream of its target promoter can act as a transcription roadblock in a distance-dependent manner and reduce background expression of downstream-placed reporter genes. We show that the transcription roadblock functions both in cognate and heterologous promoter contexts. Secondary ArsR operators placed upstream of their promoter can also improve signal-to-noise output while maintaining effector dependency. Importantly, background control can be released through the addition of micromolar concentrations of arsenite. The ArsR-operator system thus provides a flexible system for additional gene expression control, which, given the extreme sensitivity to micrograms per liter effector concentrations, could be applicable in more general contexts.