993 resultados para Anomalies immunitaires


Relevância:

10.00% 10.00%

Publicador:

Resumo:

თანამედროვე მეცნიერების მდგომარეობა შეიძლება დავახასიათოთ სიტყვებით: ტექნოლოგიური აყვავება და კონცეფტუალური კრიზისი. თანამედროვე კონცეფციებმა ამოწურეს განვითარების რესურსები, ალტერნატიული კონცეფციები კი ჯერ კიდევ არა არის ჩამოყალიბებული. შედეგად მთელი რიგი ამოცანებისა ენერგეტიკაში, მეტეოროლოგიაში, კოსოლოგიაში და მეცნიერების სხვა დარგებში ამოუხსელი რჩება. გასაღებს ახალი კონცეფციებისკენ გვაძლევს ანომალური მოვლენები. მოცემული წერილი გვთავაზობს ამოხსნებს: ენერგეტიკაში მაღალტემპერატურის მდგარადი პლაზმის პრობლემის; მეტეროგიაში ატმოსფერული ელექტროობის, ტორნადოსა და ციკლონის რიგი პრობლემების; კოსმოლოგიაში დიდი აფეთქების, ბნელი ენერგიის, გალაქტიკების უწყვეტი აჩქარების ჯერ კიდევ ამოუხსნელი ამოცანებისა. ამოხნები მიიღება საერთო ალტერნატიული კონცეფციის საფუძველზე, რომელიც ჩამოყალიბებულ იქნა მაქსველის განტოლებების ფიზიკური შინაარსის ახალი ინტერპრეტაციის შედეგად.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Three species of Scorpions beloging to two different families were studied cytologically: a) Tityus mattogrossensis Borelli (Fam. Buthidae), - This species presents spermatogonia provided with 20 short chromosomes which orient at metaphase with their axis parallelly to the plane of the equator and move toward the poles without changing this position, from the stage pachytene to metaphase the bivalents become, as in Tityus bahiensis, progressivery shorter and thicker, without showing that chiasmata occured at any time. The paired chromosomes never open themselves, out to form loops as in orthodox meioses. As in Tityus bahiensis the bivalents are inserted In the spindle before reaching their maxim contraction. No diakinesis has been observed. The primary spermatocyte metaphases are provided, with 10 pairs of chromosones, two of which are larger and two smaller than the rest. The bivalents orient as in Tityus bahiensis with their length in the plane of the equator and separate parallelly. Spindle fibres are seen alongst their entire body. While, in Tityus bahiensis the ends of the chromosomes are pronouncedly turned to opposite poles at metaphase, nothing like this was observed in the present species. Only late in anaphase the chromosomes of Tityus mattogrossensis show a bending to the poles. The secondary spermatocytes present 10 short chromosomes, two being larger than, the others. Here, on the contrary, the chromosomes are strongly curved toward the poles since the beginning of anaphase. Some chromosomal anomalies have been noticed. Primary spermatocytes with 14 bivalents, some of which representing probably free fragments, were observed. Primary spermatocytes with 8 bivalents and one cross of 4 chromosomes were interpreted as resulting from breakages followed by translocations Primary spermatocytes with 9 bivalents, one of which being much longer than the longst of the normal plates, show that fusion by the extremities of two non homologous chromosomes on the onde side, and of their respective homologous in the same way on tre other, have occured. Orientation of bivalents with their body parallelly to the spindle axis and anaphasic bridges have been encountered. All in all points to the conclusion that the chromosomes of Tityus mattogrossesis, like those of Tityus bahiensia are provided with one kinetochore at each end. Ananteris balzani Thorell - (Fam. Buthidae). - This species which belongs to the same family as Tityus, is provided with 12 chromosomes (diploid). These studied in embryonic tissues, showed the same behavior as the somatic chromosomes of Tityus bahiensis. Bothrirus sp. (Bothriuridae). - Only spermatogonia were found in the testis, of the single male hitherto investigated. The chromosomes, in number of 36, are of different sizes but small and provided, as ordinarily, with a single kinetochore. They behave therefore in an orthodox manner in mitosis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Having had the opportunity of studying a male of the species Isometrus maculatus De Qeer (Scorplones, Buthidae) the author was able to observe one of the most interesting anomalies hitherto met with in his investigations on Scorpions. This anomaly consisted in the formation by the primary spermatocyte metaphase chromosomes of a complex group of eight elements, and two independent pairs. As it is clear, the octovalent group resulted from tranlocations involving the members of four chromosome pairs. Since aside the compound group two independent bivalents were always present, 12 was estabilished as representing the diploid chromosome number of the individual, what was soon confirmed by the counts in the spermatogonia. This peculiar behavior of the chromosomes of the primary spermatocytes represents the habitual condition in the studied individual, since it was found everywhere in the whole testis. Better than any description, the figures in this, paper show what was observed. Notwithstanding the complications which may occur at anaphase, separation of the chromosomes goes normally, each pole receiving four chromosomes from the group and two from the free bivalents. Secondary spermatocytes are thus provided with six monovalents. Though not found, we may believe in the existence of secondary spermatocytes with more or lesse than six chromosomes, because it seems highly probable that lhe chromosomes of the complex may now and then passe to the wrong pole 'n consequence of an incorrect orientation. Bridge vestiges suggest that chromosomes may sometimes break. The spermatogonia have 12 short chromosomes, which bend to the poles at anaphase. The chromosomes of the present species approach, in shape and behavior, those of Tityus mattogrossensis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Two rare anomalies of the face are presented, cheiloschisis inferior (a white brazilian boy, two years old) and cheilognatoschisis inferior (a colored Brazilian boy, two years old).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El projecte desenvolupat té com a objectiu la millora en la gestió de la configuració de les màquines de rajos X de l'empresa Varpe. La principal funció d’aquestes màquines és la inspecció d'envasos de productes alimentaris, amb l'objectiu de detectar anomalies produïdes durant l'envasat. En l'actualitat la resolució d'incidències d'aquestes màquines requereix el desplaçament físic d'operaris a les localitzacions on estan situades les màquines. El projecte proporciona una nova forma de treball a partir de l'ús de bases de dades distribuïdes en les màquines de rajos X i que són gestionades per un servidor central. Entre d'altres, la principal avantatge d'aquesta gestió és que la reconfiguració i resolució d'indecències es pot realitzar fàcilment a través d'una aplicació web.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Summary Secondary lymphoid organs are sites of antigen presentation, clonal expansion of B and lymphocytes, and affinity maturation of B lymphocytes. In the intestine, these immune functions occur mainly in Peyer's patches (PP). PP develop through the interplay of two main cell types, haematopoietic cells and meserichyrnal cells. One particular haematopoietic cell type was identified as the inductive cell type in the formation of both PP and lymph nodes and was therefore designated as lymphoid tissue inducer cell. For a successful PP organogenesis, the crucial molecular components involved in the crosstalk of inducer cells and their mesenchymal target cells are adhesion molecules, lymphotoxin (LT) family members, and cytokines. In particular, the interleukin 7 receptor (IL-7R) expressed on inducer cells is absolutely required. To investigate the contribution of the ligand for the IL-7R. the cytokine IL-7, in the process of PP formation, we analyzed double transgenic (TG) mice. These mice resulted from an interbreeding of an IL-7TG mouse strain where the transgene is under the control of the MHC class II promoter with a second transgenic mouse strain, which overexpresses a transactivator for MHC class II genes. Double TG offsprings revealed higher levels of IL-7 mRNA occuring earlier in embryogenesis. Consequently, double TG mice showed a striking phenotype with a 3- to 5-fold increase in PP numbers compared to single IL-7TG or control littermates. Analysis of embryonic double TG intestines demonstrated that the process of PP development was already elevated during development as early as the embryonic day 16.5. Importantly, inducer cells were significantly increased in numbers in these embryonic intestines. Furthermore, the expression of LT? mRNA, which at this early time point is exclusively expressed by inducer cells, was also increased in double TG animals. These data clearly indicate a direct influence of IL-7 on the expansion of lymphoid tissue inducer cells and on the availability of LT? leading to a higher frequency of developing PP in fetal life. Interestingly, in addition to an enhanced frequency of PP development, in double TG mice, three additional phenotypic differences were observed. i) Lymphocyte infiltration in various non-lymphoid organs, such as stomach, salivary gland, and liver. Subsequent analysis demonstrated that B lymphocytes were predominant within these tertiary lymphoid structures. ii) Ectopic lymph node-like structures containing both B and T lymphocytes were found near the inguinal lymph node. iii) Double TG mice had a severe bone resorption syndrome most likely as a consequence of the pro-osteoclastic effect of IL-7. Taken together, these results show that IL-7 plays a key role in the homeostasis of inducer cells, in the generation of PP in the gut, in the formation of ectopic lymphoid tissue, and in bone resorption. Résumé Les organes lymphoïdes secondaires sont les lieux de présentation des antigènes aux lymphocytes, permettant l'expansion des lymphocytes B et T et la maturation d'affinité des lymphocytes B. Dans l'intestin, ces fonctions immunitaires se déroulent dans les plaques de Peyer (PP). Ces plaques se développent grâce à l'interaction des cellules hématopoïétiques avec des cellules mésenchymales. Un type particulier de cellules hématopoïétiques a été identifié comme cellule inductrice dans la formation des PP et des ganglions lymphatiques et de ce fait a été désigné cellule inductrice des tissus lymphoïdes. Durant l'organogénèse des PP, les composants moléculaires cruciaux impliqués dans l'interaction des cellules inductrices et des cellules mésenchymales sont les molécules d'adhésion, les membres de la famille des lymphotoxines (LT) et les cytokines. En particulier, le récepteur de l'interleukine 7 (IL-7R) exprimé par les cellules inductrices est absolument nécessaire. Pour étudier le rôle du ligand de l'IL-7R, l'interleukine IL-7, dans la formation des PP, nous avons croisé une lignée de souris transgénique (TG) surexprimant IL-7 sous contrôle du promoteur MHC class Il avec une lignée de souris transgénique surexprimant un transactivateur des genes MHC class II. Les souris doubles TG présentent une concentration élevée d'ARNm de l'IL-7 durant l'embryogénèse, ce qui résulte en une augmentation du nombre de PP de 3 à 5 fois en comparaison aux souris ayant seul le transgène IL-7 et aux souris contrôles. L'analyse des intestins des souris doubles TG démontre que le processus de développement des PP était élevé dès le jour 16.5 du développement embryonnaire. L'augmentation du nombre des cellules inductrices dans ces intestins embryonnaires est signilicative. De plus l'expression de l'ARNm LT?, qui à ce stade précoce est exclusivement exprimé dans les cellules inductrices, est également augmenté dans les doubles TG. Ces résultats indiquent clairement une influence directe d'IL-7 sur l'expansion des cellules inductrices des tissues lymphoïdes et sur la synthèse de LT? induisant une augmentation des PP se développant durant la vie foetale. En plus du développement accru des PP dans les souris doubles TG, trois différences phénotypiques ont été observées. i) L'infiltration lymphocytaire dans différents organes non-lymphoïdes, comme l'estomac, les glandes salivaires et le foie. Des analyses complémentaires ont demontré que les lymphocytes B étaient prédominants dans ces structures lymphoïdes tertiaires. ii) Des structures de ganglions lymphatiques ectopiques contenant des lymphocytes B et T ont été trouvées près des ganglions lymphatiques inguinaux. iii) Les souris doubles TG présentent un syndrome de résorption osseuse sévère probablement dû à l'effet pro-osteoclaste d'IL-7. Globalement, ces résultats montrent que IL-7 joue un rôle clé dans l'homéostasie des cellules inductrices dans la génèse de PP de l'intestin, dans la formation des tissus lymphoïdes ectopiques et dans la résorption osseuse.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Messages à retenir: L'identification des anomalies pleurales et parenchymateuses liées à une exposition à l'amiante est essentielle pour la reconnaissance de maladie professionnelle, avec de lourdes conséquences économiques. Le scanner thoracique est l'outil le plus fiable de ce dépistage. La détection d'anomalies dans les régions basales et sous-pleurales doit conduire à la réalisation de coupes complémentaires en procubitus sur ces régions. Le diagnostic TDM des anomalies pleurales et parenchymateuses liées à l'amiante repose sur des critères diagnostiques et un vocabulaire précis. De nombreuses images pièges peuvent mimer des plaques ou une asbestose. Une bonne connaissance de l'anatomie de l'interface pleuro-parenchymateuse et des principaux diagnostics différentiels permet souvent de redresser le diagnostic. Résumé: Le scanner multicoupe est l'outil de référence pour le dépistage des pathologies pleurales et parenchymateuses liées à l'exposition à l'amiante. Le diagnostic de plaques pleurales repose sur une surélévation quadrangulaire et nette de l'interface pleuro-parenchymateuse, dans une ou des localisation(s) évocatrice(s). Les pièges responsables de fausses images de plaques sont nombreux : structures anatomiques et variantes de la normale, opacités postéro-basales liées à des troubles ventilatoires, sarcoïdose... Les plaques doivent être différenciées des autres anomalies pleurales bénignes pouvant être rencontrées dans ce contexte, mais non spécifiques d'une exposition à l'amiante : épaississements pleuraux diffus, fibrose de la plèvre viscérale, images en pieds de corneille. La reconnaissance d'une asbestose nécessite de s'affranchir de troubles ventilatoires liés à la déclivité ou à des contraintes mécaniques focales, chroniques, telles que des ostéophytes para-vertébraux. Les coupes en procubitus permettent d'affirmer l'existence d'une pathologie interstitielle débutante dans les régions sous-pleurales et basales. Des anomalies interstitielles isolées ne peuvent être attribuées à une asbestose, de même que des anomalies interstitielles non spécifiques, associées ou non à une pathologie diffuse fibrosante.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In order to complete the study of the very rich early Tithonian (Hybonoticeras hybonotum Zone) radiolarian fauna from the Muhlheim Member of the Mornsheim Formation outcropping in the Solnhofen area, the taxa of the family Saturnalidae are described. Although rather rare, the Saturnalidae of this member contain 14 species, ten of which are new. These species belong to four genera, one of which is new (Moebicircus n. gen.), and two subfamilies (Hexasaturnalinae and Saturnalinae). The taxonomy at generic level of these late Jurassic radiolarians is founded on the basis of the position of the blades along the ring and number and morphology of the spines. Type of spines (simple or forked) has either species level value or none, depending on species. Special attention was given to anomalies, which sometimes are rather frequent, since they can give information of paleobiological and paleoecological orders. Among them frequent cases of open ring and additional spines with Dicerosaturnalis and Siamese twins skeletons with Spongosaturninus and Dicerosaturnalis are to be noted. The authors hope that this new taxonomy will give a better image of the evolution and radiation of the Saturnalidae during the Tithonian.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Samples of volcanic rocks from Alboran Island, the Alboran Sea floor and from the Gourougou volcanic centre in northern Morocco have been analyzed for major and trace elements and Sr-Nd isotopes to test current theories on the tectonic geodynamic evolution of the Alboran Sea. The Alboran Island samples are low-K tholeiitic basaltic andesites whose depleted contents of HFS elements (similar to0.5xN-MORB), especially Nb (similar to0.2xN-MORB), show marked geochemical parallels with volcanics from immature intra-oceanic arcs and back-arc basins. Several of the submarine samples have similar compositions, one showing low-Ca boninite affinity. Nd-143/Nd-144 ratios fall in the same range as many island-arc and back-arc basin samples, whereas Sr-87/Sr-86 ratios (on leached samples) are somewhat more radiogenic. Our data point to active subduction taking place beneath the Alboran region in Miocene times, and imply the presence of an associated back-arc spreading centre. Our sea floor suite includes a few more evolved dacite and rhyolite samples with (Sr-87/Sr-86)(0) up to 0.717 that probably represent varying degrees of crustal melting. The shoshonite and high-K basaltic andesite lavas from Gourougou have comparable normalized incompatible-element enrichment diagrams and Ce/Y ratios to shoshonitic volcanics from oceanic island arcs, though they have less pronounced Nb deficits. They are much less LIL- and LREE-enriched than continental arc analogues and post-collisional shoshonites from Tibet. The magmas probably originated by melting in subcontinental lithospheric mantle that had experienced negligible subduction input. Sr-Nd isotope compositions point to significant crustal contamination which appears to account for the small Nb anomalies. The unmistakable supra-subduction zone (SSZ) signature shown by our Alboran basalts and basaltic andesite samples refutes geodynamic models that attribute all Neogene volcanism in the Alboran domain to decompression melting of upwelling asthenosphere arising from convective thinning of over-thickened lithosphere. Our data support recent models in which subsidence is caused by westward rollback of an eastward-dipping subduction zone beneath the westemmost Mediterranean. Moreover, severance of the lithosphere at the edges of the rolling-back slab provides opportunities for locally melting lithospheric mantle, providing a possible explanation for the shoshonitic volcanism seen in northern Morocco and more sporadically in SE Spain. (C) 2004 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The algorithmic approach to data modelling has developed rapidly these last years, in particular methods based on data mining and machine learning have been used in a growing number of applications. These methods follow a data-driven methodology, aiming at providing the best possible generalization and predictive abilities instead of concentrating on the properties of the data model. One of the most successful groups of such methods is known as Support Vector algorithms. Following the fruitful developments in applying Support Vector algorithms to spatial data, this paper introduces a new extension of the traditional support vector regression (SVR) algorithm. This extension allows for the simultaneous modelling of environmental data at several spatial scales. The joint influence of environmental processes presenting different patterns at different scales is here learned automatically from data, providing the optimum mixture of short and large-scale models. The method is adaptive to the spatial scale of the data. With this advantage, it can provide efficient means to model local anomalies that may typically arise in situations at an early phase of an environmental emergency. However, the proposed approach still requires some prior knowledge on the possible existence of such short-scale patterns. This is a possible limitation of the method for its implementation in early warning systems. The purpose of this paper is to present the multi-scale SVR model and to illustrate its use with an application to the mapping of Cs137 activity given the measurements taken in the region of Briansk following the Chernobyl accident.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Objectifs: Évaluer l'apport de l'angioscanographie dans le cadre d'hémoptysies (1) dans la localisation des artères pathologiques, bronchiques (AB) et systémiques non bronchiques (ASNB) ou artérielles pulmonaires, (2) la localisation de la source du saignement et (3) les anomalies parenchymateuses responsables ou secondaires au saignement en comparaison avec les données angiographiques. Matériels et méthodes: 25 patients consécutifs (12 femmes, 13 hommes) d'un âge moyen de 50 ± 39 ans (min 15, max 89) ont été inclus dans l'étude. Les signes TDM ont été comparés aux signes angiographiques. Résultats: Les artères bronchiques ont été correctement identifiées dans 20 cas. Des ASNB anormales ont été identifiées dans 5 cas chez 4 patients. La TDM a correctement prédit le site d'embolisation dans 19 cas (76%). Les AB étaient responsables de l'hémoptysie dans 25 cas et les ASNB dans 4 cas. Les affections causales ou associées étaient les suivantes: carcinome bronchopulmonaire (n=11), hémangioendothéliome malin (n=1), mucoviscidose (n=7), hémoptysie cryptogénique au cours d'une BPCO (n=1), bronchectasies focales (n=4) et séquelles de tuberculose avec bronchectasies (n=1). Conclusion: Les signes directs et indirects en Angio-TDM sont utiles pour obtenir une visualisation globale des AB et ASNB anormales. Néanmoins, le site optimal d'embolisation ne peut toujours être prédit.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

PURPOSE: Investigation of the incidence and distribution of congenital structural cardiac malformations among the offspring of mothers with diabetes type 1 and of the influence of periconceptional glycemic control. METHODS: Multicenter retrospective clinical study, literature review, and meta-analysis. The incidence and pattern of congenital heart disease in the own study population and in the literature on the offspring of type 1 diabetic mothers were compared with the incidence and spectrum of the various cardiovascular defects in the offspring of nondiabetic mothers as registered by EUROCAT Northern Netherlands. Medical records were, in addition, reviewed for HbA(1c) during the 1st trimester. RESULTS: The distribution of congenital heart anomalies in the own diabetic study population was in accordance with the distribution encountered in the literature. This distribution differed considerably from that in the nondiabetic population. Approximately half the cardiovascular defects were conotruncal anomalies. The authors' study demonstrated a remarkable increase in the likelihood of visceral heterotaxia and variants of single ventricle among these patients. As expected, elevated HbA(1c) values during the 1st trimester were associated with offspring fetal cardiovascular defects. CONCLUSION: This study shows an increased likelihood of specific heart anomalies, namely transposition of the great arteries, persistent truncus arteriosus, visceral heterotaxia and single ventricle, among offspring of diabetic mothers. This suggests a profound teratogenic effect at a very early stage in cardiogenesis. The study emphasizes the frequency with which the offspring of diabetes-complicated pregnancies suffer from complex forms of congenital heart disease. Pregnancies with poor 1st-trimester glycemic control are more prone to the presence of fetal heart disease.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The molecular characterization of balanced chromosomal rearrangements have always been of advantage in identifying disease-causing genes. Here, we describe the breakpoint mapping of a de novo balanced translocation t(7;12)(q11.22;q14.2) in a patient presenting with a failure to thrive associated with moderate mental retardation, facial anomalies, and chronic constipation. The localization of the breakpoints and the co-occurrence of Williams-Beuren syndrome and 12q14 microdeletion syndrome phenotypes suggested that the expression of some of the dosage-sensitive genes of these two segmental aneuploidies were modified in cells of the proposita. However, we were unable to identify chromosomes 7 and/or 12-mapping genes that showed disturbed expression in the lymphoblastoids of the proposita. This case showed that position-effect might operate in some tissues, but not in others. It also illustrates the overlap of phenotypes presented by patients with the recently described 12q14 structural rearrangements.