60 resultados para intermediate cementum


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The etiology of feline dental resorptive lesions is unknown, but some evidence suggests that interactions between components of the periodontium may be initiating factors in the development of these lesions. In the present study, 22 clinically normal teeth were harvested from 7 cats. The teeth and periodontium were radiographed and examined histologically. In addition, 14 of the 22 teeth were examined histometrically. Two teeth were histologically normal with an open apical foramen and two were normal with a closed apical foramen. Histological evidence of periodontal ligament degeneration without cementum resorption was observed in 8 teeth, and varying degrees of cementum resorption were observed in 10 teeth. Mandibular molar and premolar teeth had distal drift, and mandibular canine teeth had mesial drift. Alterations in the periodontal ligament may represent a preclinical stage of dental resorption.

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Growth codes are a subclass of Rateless codes that have found interesting applications in data dissemination problems. Compared to other Rateless and conventional channel codes, Growth codes show improved intermediate performance which is particularly useful in applications where partial data presents some utility. In this paper, we investigate the asymptotic performance of Growth codes using the Wormald method, which was proposed for studying the Peeling Decoder of LDPC and LDGM codes. Compared to previous works, the Wormald differential equations are set on nodes' perspective which enables a numerical solution to the computation of the expected asymptotic decoding performance of Growth codes. Our framework is appropriate for any class of Rateless codes that does not include a precoding step. We further study the performance of Growth codes with moderate and large size codeblocks through simulations and we use the generalized logistic function to model the decoding probability. We then exploit the decoding probability model in an illustrative application of Growth codes to error resilient video transmission. The video transmission problem is cast as a joint source and channel rate allocation problem that is shown to be convex with respect to the channel rate. This illustrative application permits to highlight the main advantage of Growth codes, namely improved performance in the intermediate loss region.

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Aim The global spread of woody plants into grasslands is predicted to increase over the coming century. While there is general agreement regarding the anthropogenic causes of this phenomenon, its ecological consequences are less certain. We analysed how woody vegetation of differing cover affects plant diversity (richness and evenness) and the surrogates of multiple ecosystem processes (multifunctionality) in global drylands, and how these change with aridity. Location Two hundred and twenty-four dryland sites from all continents except Antarctica, widely differing in their environmental conditions (from arid to dry-subhumid sites) and relative woody cover (from 0 to 100). Methods Using a standardized field survey, we measured the cover, richness and evenness of perennial vegetation. At each site, we measured 14 soil variables related to fertility and the build-up of nutrient pools. These variables are critical for maintaining ecosystem functioning in drylands. Results Species richness and ecosystem multifunctionality were strongly related to woody vegetation, with both variables peaking at a relative woody cover (RWC) of 41–60. This relationship shifted with aridity. We observed linear positive effects of RWC in dry-subhumid sites. These positive trends shifted to hump-shaped RWC–diversity and multifunctionality relationships under semi-arid environments. Finally, hump-shaped (richness, evenness) or linear negative (multifunctionality) effects of RWC were found under the most arid conditions. Main conclusions Plant diversity and multifunctionality peaked at intermediate levels of woody cover, although this relationship became increasingly positive in wetter environments. This comprehensive study accounts for multiple ecosystem attributes across a range of levels of woody cover and environmental conditions. Our results help us to reconcile contrasting views of woody encroachment found in the current literature and can be used to improve predictions of the likely effects of encroachment on biodiversity and ecosystem services.

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A 7-year-old boy was presented with a long-standing slowly growing mass of the left supraorbital area. A biopsy specimen revealed a bland spindle cell proliferation with scattered polygonal cells with acidophilic cytoplasm and cross-striations. Our differential diagnosis included rhabdomyoma of fetal type, leiomyoma with trapping of regenerating skeletal muscle elements, and rhabdomyomatous mesenchymal hamartoma of the skin. Immunohistochemistry demonstrated strong positivity of myoglobin and desmin as well as negativity of caldesmon, suggesting skeletal muscle lineage. The excisional specimen confirmed our diagnosis of cutaneous fetal rhabdomyoma of intermediate type. Additional immunostaining performed on the excisional specimen showed strong Wilms Tumor 1 but only a very faint and focal p63 expression.

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A large scale, 10 step synthesis of cyclopentanone 1 , starting from the chiral pool compound D-mannose, is described. The synthesis proceeds via a ring closing metathesis reaction as the key step in an overall yield of 23%. Cyclopentanone 1 is a central intermediate for the synthesis of tricyclo-DNA

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A typical multivesiculated metacestode tissue has been found in the liver of a European brown hare (Lepus europaeus) originating from a northern area of Switzerland. In this study, the causative species was identified as Echinococcus multilocularis by appropriate histological and molecular analyses and corresponding DNA sequencing. This is the first confirmation of larval E. multilocularis from hares in central Europe. The metacestode tissue contained protoscolices, suggesting that the hare may contribute to the transmission of E. multilocularis in Switzerland.

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Minutes of the Advisory Board meeting; status of projects and financial overview for the period; perspectives for the second half of 2004.

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Selection on naturally occurring hybrid individuals is a key component of speciation theory, but few studies examine the functional basis of hybrid performance. We examine the functional consequences of hybridization in nature, using the freshwater sunfishes (Centrarchidae), where natural hybrids have been studied for more than a century and a half. We examined bluegill (Lepomis macrochirus), green sunfish (Lepomis cyanellus), and their naturally occurring hybrid, using prey-capture kinematics and morphology to parameterize suction-feeding simulations on divergent parental resources. Hybrid individuals exhibited kinematics intermediate between those of the two parental species. However, performance assays indicated that hybrids display performance most similar to the worse-performing species for a given parental resource. Our results show that intermediate hybrid phenotypes can be impaired by a less-than-intermediate performance and hence suffer a larger loss in fitness than could be inferred from morphology alone.

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The absolute sign of local polarity in relation to the biological growth direction has been investigated for teeth cementum using phase sensitive second harmonic generation microscopy (PS-SHGM) and a crystal of 2-cyclooctylamino-5-nitropyridine (COANP) as a nonlinear optic (NLO) reference material. A second harmonic generation (SHG) response was found in two directions of cementum: radial (acellular extrinsic fibers that are oriented more or less perpendicular to the root surface) and circumferential (cellular intrinsic fibers that are oriented more or less parallel to the surface). A mono-polar state was demonstrated for acellular extrinsic cementum. However, along the different parts of cementum in circumferential direction, two corresponding domains were observed featuring an opposite sign of polarity indicative for a bi-polar microscopic state of cellular intrinsic cementum. The phase information showed that the orientation of radial collagen fibrils of cementum is regularly organized with the donor (D) groups pointing to the surface. Circumferential collagen molecules feature orientational disorder and are oriented up and down in random manner showing acceptor or donor groups at the surface of cementum. Considering that the cementum continues to grow in thickness throughout life, we can conclude that the cementum is growing circumferentially in two opposite directions and radially in one direction. A Markov chain type model for polarity formation in the direction of growth predicts D-groups preferably appearing at the fiber front.

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Protein-protein interactions are fundamental for most biological processes, such as the formation of cellular structures and enzymatic complexes or in signaling pathways. The identification and characterization of protein-protein interactions are therefore essential for understanding the mechanisms and regulation of biological systems. The organization and dynamics of the cytoskeleton, as well as its anchorage to specific sites in the plasma membrane and organelles, are regulated by the plakins. These structurally related proteins anchor different cytoskeletal networks to each other and/or to other cellular structures. The association of several plakins with intermediate filaments (IFs) is critical for maintenance of the cytoarchitecture. Pathogenic mutations in the genes encoding different plakins can lead to dramatic manifestations, occurring principally in the skin, striated muscle, and/or nervous system, due to cytoskeletal disorganization resulting in abnormal cell fragility. Nevertheless, it is still unclear how plakins bind to IFs, although some general rules are slowly emerging. We here describe in detail a recently developed protein-protein fluorescence binding assay, based on the production of recombinant proteins tagged with green fluorescent protein (GFP) and their use as fluid-phase fluorescent ligands on immobilized IF proteins. Using this method, we have been able to assess the ability of C-terminal regions of GFP-tagged plakin proteins to bind to distinct IF proteins and IF domains. This simple and sensitive technique, which is expected to facilitate further studies in this area, can also be potentially employed for any kind of protein-protein interaction studies.

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BACKGROUND Newly diagnosed WHO grade II-III or any WHO grade recurrent meningioma exhibit an aggressive behavior and thus are considered as high- or intermediate risk tumors. Given the unsatisfactory rates of disease control and survival after primary or adjuvant radiation therapy, optimization of treatment strategies is needed. We investigated the potential of dose-painting intensity-modulated proton beam-therapy (IMPT) for intermediate- and high-risk meningioma. MATERIAL AND METHODS Imaging data from five patients undergoing proton beam-therapy were used. The dose-painting target was defined using [68]Ga-[1,4,7,10-tetraazacyclododecane tetraacetic acid]- d-Phe(1),Tyr(3)-octreotate ([68]Ga-DOTATATE)-positron emission tomography (PET) in target delineation. IMPT and photon intensity-modulated radiation therapy (IMRT) treatment plans were generated for each patient using an in-house developed treatment planning system (TPS) supporting spot-scanning technology and a commercial TPS, respectively. Doses of 66 Gy (2.2 Gy/fraction) and 54 Gy (1.8 Gy/fraction) were prescribed to the PET-based planning target volume (PTVPET) and the union of PET- and anatomical imaging-based PTV, respectively, in 30 fractions, using simultaneous integrated boost. RESULTS Dose coverage of the PTVsPET was equally good or slightly better in IMPT plans: dose inhomogeneity was 10 ± 3% in the IMPT plans vs. 13 ± 1% in the IMRT plans (p = 0.33). The brain Dmean and brainstem D50 were small in the IMPT plans: 26.5 ± 1.5 Gy(RBE) and 0.002 ± 0.0 Gy(RBE), respectively, vs. 29.5 ± 1.5 Gy (p = 0.001) and 7.5 ± 11.1 Gy (p = 0.02) for the IMRT plans, respectively. The doses delivered to the optic structures were also decreased with IMPT. CONCLUSIONS Dose-painting IMPT is technically feasible using currently available planning tools and resulted in dose conformity of the dose-painted target comparable to IMRT with a significant reduction of radiation dose delivered to the brain, brainstem and optic apparatus. Dose escalation with IMPT may improve tumor control and decrease radiation-induced toxicity.

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Sentinel lymph node (SLN) detection techniques have the potential to change the standard of surgical care for patients with prostate cancer. We performed a lymphatic mapping study and determined the value of fluorescence SLN detection with indocyanine green (ICG) for the detection of lymph node metastases in intermediate- and high-risk patients undergoing radical prostatectomy and extended pelvic lymph node dissection. A total of 42 patients received systematic or specific ICG injections into the prostate base, the midportion, the apex, the left lobe, or the right lobe. We found (1) that external and internal iliac regions encompass the majority of SLNs, (2) that common iliac regions contain up to 22% of all SLNs, (3) that a prostatic lobe can drain into the contralateral group of pelvic lymph nodes, and (4) that the fossa of Marcille also receives significant drainage. Among the 12 patients who received systematic ICG injections, 5 (42%) had a total of 29 lymph node metastases. Of these, 16 nodes were ICG positive, yielding 55% sensitivity. The complex drainage pattern of the prostate and the low sensitivity of ICG for the detection of lymph node metastases reported in our study highlight the difficulties related to the implementation of SNL techniques in prostate cancer. PATIENT SUMMARY There is controversy about how extensive lymph node dissection (LND) should be during prostatectomy. We investigated the lymphatic drainage of the prostate and whether sentinel node fluorescence techniques would be useful to detect node metastases. We found that the drainage pattern is complex and that the sentinel node technique is not able to replace extended pelvic LND.

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The enzyme catalysing the reduction of adenosine 5′-phosphosulfate (AdoPS) to sulfite in higher plants, AdoPS reductase, is considered to be the key enzyme of assimilatory sulfate reduction. In order to address its reaction mechanism, the APR2 isoform of this enzyme from Arabidopsis thaliana was overexpressed in Escherichia coli and purified to homogeneity. Incubation of the enzyme with [35S]AdoPS at 4 °C resulted in radioactive labelling of the protein. Analysis of APR2 tryptic peptides revealed 35SO2–3 bound to Cys248, the only Cys conserved between AdoPS and prokaryotic phosphoadenosine 5′-phosphosulfate reductases. Consistent with this result, radioactivity could be released from the protein by incubation with thiols, inorganic sulfide and sulfite. The intermediate remained stable, however, after incubation with sulfate, oxidized glutathione or AdoPS. Because truncated APR2, missing the thioredoxin-like C-terminal part, could be labelled even at 37 °C, and because this intermediate was more stable than the complete protein, we conclude that the thioredoxin-like domain was required to release the bound SO2–3 from the intermediate. Taken together, these results demonstrate for the first time the binding of 35SO2–3 from [35S]AdoPS to AdoPS reductase and its subsequent release, and thus contribute to our understanding of the molecular mechanism of AdoPS reduction in plants.