Étude du rôle de la membrane basale spécialisée dans la maturation de l'émail

Les cellules épithéliales qui produisent l’émail, les améloblastes, sont séparées de l'émail au niveau de la zone de maturation par une membrane basale spécialisée (MBS) enrichie en laminine 332 (LM-332). Cette protéine hétérotrimérique (composée des chaînes α3, ß3 et γ2) assure l'intégrité structurelle des membranes basales (MB) et influence divers processus cellulaires épithéliaux tels que l'adhésion et la différenciation cellulaire. Des modèles de souris « knockout » (KO), où les gènes codant pour LM-332 ont été supprimés, meurent peu après la naissance. Néanmoins, ce phénotype létal peut être contourné en substituant chez la souris le gène produisant la chaîne γ2 de la laminine (LAMC2) par sa forme humaine, sous le contrôle de l’expression du promoteur-rtTA, de la cytokératine 14, inductible par la prise de doxycycline (Dox) - (Tet-on). Le but de ce projet est d’examiner si l’utilisation de cette protéine humaine chez la souris a un effet sur la structuration de la MBS ainsi que sur la maturation de l'émail. La phase de maturation de l’organe de l’émail chez la souris transgénique a été sévèrement altérée par rapport à une souris normale (WT). La MBS n’est plus visible, une matrice dystrophique s’est formée dans la couche d'émail dans la phase de maturation, et la présence d’une matrice résiduelle de l'émail est observée durant la phase tardive de maturation. Des micro-analyses tomographiques ont révélé une usure excessive des surfaces occlusales des molaires, un écroulement de l'émail sur les pointes des incisives et une hypominéralisation de l'émail. Cependant, aucune altération structurale due à cette recombinaison transgénique n’a été observée dans d'autres sites épithéliaux, tels que la peau, le palais et la langue. Ces résultats indiquent que, bien que ce modèle de souris humanisée soit capable de rétablir ses fonctions dans divers tissus épithéliaux, il est incapable de soutenir la structuration d'une MBS à l'interface entre les améloblastes et l’émail en maturation. Cet échec peut être lié à la composition spécifique de la MBS dans la phase de maturation et supporte l’hypothèse que la MBS est essentielle pour la maturation adéquate de l'émail.The epithelial ameloblasts are separated from the maturing enamel by an atypical basement membrane (BM) that is enriched in laminin 332 (LM-332). This heterotrimeric protein (α3, ß3 and γ2 chains) provides structural integrity to BMs and influences various epithelial cell processes including cell adhesion and differentiation. Mouse models that lack expression of individual LM-332 chains die shortly after birth. The lethal phenotype of laminin γ2 knockout mice can be rescued by human laminin γ2 (LAMC2) expressed using a doxycycline-inducible (Tet-on) cytokeratin 14 promoter-rtTA. These otherwise normal-looking rescued mice exhibit white spot lesions on incisors. We therefore investigated the effect of rescue with human LAMC2 on enamel maturation and structuring of the atypical BM. The maturation stage enamel organ in transgenic mice was severely altered as compared to wild type controls, a structured BM was no longer discernible, dystrophic matrix appeared in the maturing enamel layer, and there was residual enamel matrix late into the maturation stage. Microtomographic scans revealed excessive wear of occlusal surfaces on molars, chipping of enamel on incisor tips, and hypomineralization of the enamel layer. No structural alterations were observed at other epithelial sites, such as skin, palate and tongue. These results indicate that while this humanized mouse model is capable of rescue in various epithelial tissues, it is unable to sustain structuring of a proper BM at the interface between ameloblasts and maturing enamel. This failure may be related to the atypical composition of the BM in the maturation stage and reaffirms that the atypical BM is essential for enamel maturation

Tactile myography: an off-line assessment on intact subjects and one upper-limb disabled

Castellini C, Kõiva R, Pasluosta C, Viegas C, Eskofier BM. Tactile myography: an off-line assessment on intact subjects and one upper-limb disabled. Technologies / SI: Assistive Robotics. 2018;6(2): 38.Human-machine interfaces to control prosthetic devices still suffer from scarce dexterity and low reliability; for this reason, the community of assistive robotics is exploring novel solutions to the problem of myocontrol. In this work, we present experimental results pointing in the direction that one such method, namely Tactile Myography (TMG), can improve the situation. In particular, we use a shape-conformable high-resolution tactile bracelet wrapped around the forearm/residual limb to discriminate several wrist and finger activations performed by able-bodied subjects and a trans-radial amputee. Several combinations of features/classifiers were tested to discriminate among the activations. The balanced accuracy obtained by the best classifier/feature combination was on average 89.15% (able-bodied subjects) and 88.72% (amputated subject); when considering wrist activations only, the results were on average 98.44% for the able-bodied subjects and 98.72% for the amputee. The results obtained from the amputee were comparable to those obtained by the able-bodied subjects. This suggests that TMG is a viable technique for myoprosthetic control, either as a replacement of or as a companion to traditional surface electromyography

Oxidative Stress: How Has It Been Considered in the Design of New Drug Candidates for Neurodegenerative Diseases?

Editorial on the Research Topi

In vivo dosimetry of thyroid doses from different irradiated sites in children and adolescents: a cross-sectional study

Background: Scattered radiation can be assessed by in vivo dosimetry. Thyroid tissue is sensitive to radiation, even at doses <10 cGy. This study compared the scattered dose to the thyroid measured by thermoluminescent dosimeters (TLDs) and the estimated one by treatment planning system (TPS). Methods: During radiotherapy to sites other than the thyroid of 16 children and adolescents, seventy-two TLD measurements at the thyroid were compared with TPS estimation. Results: The overall TPS/TLD bias was 1.02 (95% LA 0.05 to 21.09). When bias was stratified by treatment field, the TPS overestimated TLD values at doses <1 cGy and underestimated them at doses >10 cGy. The greatest bias was found in pelvis and abdomen: 15.01 (95% LA 9.16 to 24.61) and 5.12 (95% LA 3.04 to 8.63) respectively. There was good agreement in orbit, head, and spine: bias 1.52 (95% LA 0.48 to 4.79), 0.44 (95% LA 0.11 to 1.82) and 0.83 (0.39 to 1.76) respectively. There was small agreement with broad limits for lung and mediastinum: 1.13 (95% LA 0.03 to 40.90) and 0.39 (95% LA 0.02 to 7.14) respectively. Conclusions: The scattered dose can be measured with TLDs, and TPS algorithms for outside structures should be improved

Estudo sobre a redução seletiva de acetatos alílicos em precursores de sesquiterpenos

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Primary Malignant Mucosal Melanoma of the Esophagus. A Case Report

Primary malignant melanoma isa rare lesion, that accounts for only 0.1 % of primary esophageal malignant neoplasms. The tumor is polypoid, pedunculated and sometimes ulcerated. Symptoms are similar to those of squamous cell carcinoma and the preoperative differential diagnosis is important. Surgical resection is the treatment of choice. In tracavitary radiotherapy may be a useful form of adjuvant therapy in selected patients. Here we record the case of a 67 years old man with a primary malignant melanama of the esophagus. He underwent an esophagectomy, and is stili alive 5 months aftnr lhe procedure

The Genus Caesalpinia L. (Caesalpiniaceae): Phytochemical and Pharmacological Characteristics

The genus Caesalpinia (Caesalpiniaceae) has more than 500 species, many of which have not yet been investigated for potential pharmacological activity. Several classes of chemical compounds, such as flavonoids, diterpenes, and steroids, have been isolated from various species of the genus Caesalpinia. It has been reported in the literature that these species exhibit a wide range of pharmacological properties, including antiulcer, anticancer, antidiabetic, anti-inflammatory, antimicrobial, and antirheumatic activities that have proven to be efficacious in ethnomedicinal practices. in this review we present chemical and pharmacological data from recent phytochemical studies on various plants of the genus Caesalpinia.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Univ Fed Alfenas, Inst Chem, BR-37130000 Alfenas, MG, BrazilUniversidade Federal de São Paulo, Inst Environm Chem & Pharmaceut Sci, BR-09972 Diadema, SP, BrazilUniversidade Federal de São Paulo, Inst Environm Chem & Pharmaceut Sci, BR-09972 Diadema, SP, BrazilWeb of Scienc

O efeito da quercetina em mucosa gástrica e fígado de ratos com hipertensão porta experimental

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Teoria Materialista do Estado e da Forma Política como Vetor Epistemológico para Análise da Violência Doméstica e Familiar

This article seeks to highlight the relevance of the dialectical epistemological vector developed by the Materialist Theory of the State for the study of domestic and family violence against women, contributing to the reelaboration of a critical epistemology that is attentive to the contradictions of the State in its relationship with society. Thus, the objectives of this article are: a) to express briefly the main contours of the Materialist Theory of the State and Political Form; b) to verify if there is coherence between the epistemological vector discussed, which is Marxist in nature, and the commitment to the Democratic State of Law; c) to substantiate the relevance of the category Political Form within gender studies. To achieve these goals, the research was based on a dialectical approach and on bibliographic and documental research techniques. The scientific path followed culminated in the confirmation of the initial hypothesis: the epistemological vector of the theoretical framework studied corresponds to a coherent epistemological path for understanding the dynamics between the State and domestic and family violence. Keywords: Materialist State Theory; Political Form; Epistemological Vector; Domestic and Family Violence.O presente artigo busca destacar a relevância do vetor epistemológico dialético elaborado a partir da Teoria Materialista do Estado para a compreensão da violência doméstica e familiar contra a mulher, contribuindo para reelaboração de uma epistemologia crítica e atenta as contradições internas entre o Estado e suas relações com a sociedade. Assim, são objetivos deste artigo: a) sistematizar os principais elementos da Teoria Materialista do Estado e da Forma Política; b) verificar se há coerência entre o vetor epistemológico discutido, de cunho marxista, e o compromisso com o Estado Democrático de Direito; c) fundamentar a pertinência da categoria Forma Política dentro dos estudos de gênero. Para concretizar tais fins, a elaboração da pesquisa pautou-se na abordagem dialética e em técnicas de pesquisa de natureza bibliográfica e documental. O caminho científico traçado culminou na confirmação da hipótese inicial: o vetor epistemológico do marco teórico estudado corresponde a um caminho epistemológico coerente para compreensão das dinâmicas entre o Estado e a violência doméstica e familiar