936 resultados para paleogeographical and paleoecological significance
Resumo:
The vast network of hedges in Ireland provide habitats of great importance to the wildlife of the country, yet surprisingly enough, only very limited survey work has been carried out on our hedgerows in the past. Now with the implementation of the new Rural Environmental Protection Scheme, farmers will be paid to manage their hedgerows in such a way as to make them into increasingly attractive wildlife habitats. However, hedgerow management expertise seems to be somewhat lacking in Ireland and we must draw upon the knowledge of our neighbours in the E.U. where quite an amount of research has been carried out on this subject. The aim of this study is to present the relevant aspects of the research for the benefit of the people who will be involved in the administration of the Rural Environmental Protection Scheme and to anyone else involved in hedgerow management.
Resumo:
The males of the sandfly Lutzomyia longipalpis occur in two forms, one which bears a single pair of pale spots on tergite 4 and another in which an additional pair of spots characterizes tergite 3. In crosses between laboratory reared stocks of the two forms originating from allopatric and sympatric sites in Brazil nearly all males of one form fail to inseminate females of the other. In addition, insemination failure between some allopatric populaytions of Lu. longipalpis with similar tergal spot patterns is recorded, indicating the existence of additional forms in an apparent species complex. The possibility that Lu. longipalpis sensu latu represents more than a single taxon is discussed and the relevance of these findings to future epidemiological studies on kala-azar is considered.
Resumo:
Intrarenal neurotransmission implies the co-release of neuropeptides at the neuro-effector junction with direct influence on parameters of kidney function. The presence of an angiotensin (Ang) II-containing phenotype in catecholaminergic postganglionic and sensory fibers of the kidney, based on immunocytological investigations, has only recently been reported. These angiotensinergic fibers display a distinct morphology and intrarenal distribution, suggesting anatomical and functional subspecialization linked to neuronal Ang II-expression. This review discusses the present knowledge concerning these fibers, and their significance for renal physiology and the pathogenesis of hypertension in light of established mechanisms. The data suggest a new role of Ang II as a co-transmitter stimulating renal target cells or modulating nerve traffic from or to the kidney. Neuronal Ang II is likely to be an independent source of intrarenal Ang II. Further physiological experimentation will have to explore the role of the angiotensinergic renal innervation and integrate it into existing concepts.
Resumo:
In hyperdiploid acute lymphoblastic leukaemia (ALL), the simultaneous occurrence of specific aneuploidies confers a more favourable outcome than hyperdiploidy alone. Interphase (I) FISH complements conventional cytogenetics (CC) through its sensitivity and ability to detect chromosome aberrations in non-dividing cells. To overcome the limits of manual I-FISH, we developed an automated four-colour I-FISH approach and assessed its ability to detect concurrent aneuploidies in ALL. I-FISH was performed using centromeric probes for chromosomes 4, 6, 10 and 17. Parameters established for automatic nucleus selection and signal detection were evaluated (3 controls). Cut-off values were determined (10 controls, 1000 nuclei/case). Combinations of aneuploidies were considered relevant when each aneuploidy was individually significant. Results obtained in 10 ALL patients (1500 nuclei/patient) were compared with those by CC. Various combinations of aneuploidies were identified. All clones detected by CC were observed by I-FISH. I-FISH revealed numerous additional abnormal clones, ranging between 0.1 % and 31.6%, based on the large number of nuclei evaluated. Four-colour automated I-FISH permits the identification of concurrent aneuploidies of prognostic significance in hyperdiploid ALL. Large numbers of cells can be analysed rapidly by this method. Owing to its high sensitivity, the method provides a powerful tool for the detection of small abnormal clones at diagnosis and during follow up. Compared to CC, it generates a more detailed cytogenetic picture, the biological and clinical significance of which merits further evaluation. Once optimised for a given set of probes, the system can be easily adapted for other probe combinations.
Resumo:
Cancer-testis (CT) antigens comprise families of tumor-associated antigens that are immunogenic in patients with various cancers. Their restricted expression makes them attractive targets for immunotherapy. The aim of this study was to determine the expression of several CT genes and evaluate their prognostic value in head and neck squamous cell carcinoma (HNSCC). The pattern and level of expression of 12 CT genes (MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, MAGE-C2, NY-ESO-1, LAGE-1, SSX-2, SSX-4, BAGE, GAGE-1/2, GAGE-3/4) and the tumor-associated antigen encoding genes PRAME, HERV-K-MEL, and NA-17A were evaluated by RT-PCR in a panel of 57 primary HNSCC. Over 80% of the tumors expressed at least 1 CT gene. Coexpression of three or more genes was detected in 59% of the patients. MAGE-A4 (60%), MAGE-A3 (51%), PRAME (49%) and HERV-K-MEL (42%) were the most frequently expressed genes. Overall, the pattern of expression of CT genes indicated a coordinate regulation; however there was no correlation between expression of MAGE-A3/A4 and BORIS, a gene whose product has been implicated in CT gene activation. The presence of MAGE-A and NY-ESO-1 proteins was verified by immunohistochemistry. Analysis of the correlation between mRNA expression of CT genes with clinico-pathological characteristics and clinical outcome revealed that patients with tumors positive for MAGE-A4 or multiple CT gene expression had a poorer overall survival. Furthermore, MAGE-A4 mRNA positivity was prognostic of poor outcome independent of clinical parameters. These findings indicate that expression of CT genes is associated with a more malignant phenotype and suggest their usefulness as prognostic markers in HNSCC.
Resumo:
Objectives:¦The aim of this study was to estimate the prevalence of subclinical small joint synovitis detected by ultrasonography in patients with axial SpA, and to evaluate their relevance in terms of function or and disease activity.¦Methods:¦Forty axial SpA patients, 40 RA and 20 healthy subjects were evaluated by ultrasonography, using a reproducible semi-quantitative score by B-mode and Doppler, for synovitis, while disease activity and function were assessed using validated instruments (DAS28, BASDAI, BASFI, m-SACRAH and HAQ).¦Results:¦Median B-mode score were respectively 8.2 for axial SpA, 11.5 for RA and 6.0 for healthy subjects, corresponding to a prevalence of clinical significant synovitis of respectively 37.5%, 60% and 11% for a level of significance at > 8 chosen to¦classify as active > 75% of RA patient with DAS28 >2.6 and < 10% of controls. Addtionally, Doppler was positive in 8% of SpA, 30 % of RA and none of the healthy subjects. Echographic synovitis correlated with disease activity (DAS28) and function¦(HAQ, mSACRAH) in RA patients, but no correlation were found for SpA patients with disease activity (BASDAI) or function (BASFI, HAQ, mSACRAH). Cases of synovitis using classification by Doppler positivity were insufficient to allow any¦statistical analysis.¦Conclusions:¦B-mode ultrasonographic evaluation can demonstrate subclinical synovitis in almost 40% of SpA patients, but they do not appear to correlate with disease activity or function on the contrary to what is observed in RA patients, representing potentially different processes
Resumo:
In high hyperdiploid acute lymphoblastic leukemia (ALL), the concurrence of specific trisomies confers a more favorable outcome than hyperdiploidy alone. Interphase fluorescence in situ hybridization (FISH) complements conventional cytogenetics (CC) through its sensitivity and ability to detect chromosome aberrations in nondividing cells. To overcome the limits of manual I-FISH, we developed an automated four-color I-FISH approach and assessed its ability to detect concurrent aneuploidies in ALL. I-FISH was performed using centromeric probes for chromosomes 4, 6, 10, and 17. Parameters established for nucleus selection and signal detection were evaluated. Cutoff values were determined. Combinations of aneuploidies were considered relevant when each aneuploidy was individually significant. Results obtained in 10 patient samples were compared with those obtained with CC. Various combinations of aneuploidies were identified. All clones detected by CC were observed also by I-FISH, and I-FISH revealed numerous additional abnormal clones in all patients, ranging from < or =1% to 31.6% of cells analyzed. We conclude that four-color automated I-FISH permits the identification of concurrent aneuploidies of potential prognostic significance. Large numbers of cells can be analyzed rapidly. The large number of nuclei scored revealed a high level of chromosome variability both at diagnosis and relapse, the prognostic significance of which is of considerable clinical interest and merits further evaluation.
Resumo:
In hyperdiploid acute lymphoblastic leukaemia (ALL), the simultaneous occurrence of specific aneuploidies confers a more favourable outcome than hyperdiploidy alone. Interphase (I) FISH complements conventional cytogenetics (CC) through its sensitivity and ability to detect chromosome aberrations in non-dividing cells. To overcome the limits of manual I-FISH, we developed an automated four-colour I-FISH approach and assessed its ability to detect concurrent aneuploidies in ALL. I-FISH was performed using centromeric probes for chromosomes 4, 6, 10 and 17. Parameters established for automatic nucleus selection and signal detection were evaluated (3 controls). Cut-off values were determined (10 controls, 1000 nuclei/case). Combinations of aneuploidies were considered relevant when each aneuploidy was individually significant. Results obtained in 10 ALL patients (1500 nuclei/patient) were compared with those by CC. Various combinations of aneuploidies were identified. All clones detected by CC were observed by I-FISH. I-FISH revealed numerous additional abnormal clones, ranging between 0.1% and 31.6%, based on the large number of nuclei evaluated. Four-colour automated I-FISH permits the identification of concurrent aneuploidies of prognostic significance in hyperdiploid ALL. Large numbers of cells can be analysed rapidly by this method. Owing to its high sensitivity, the method provides a powerful tool for the detection of small abnormal clones at diagnosis and during follow up. Compared to CC, it generates a more detailed cytogenetic picture, the biological and clinical significance of which merits further evaluation. Once optimised for a given set of probes, the system can be easily adapted for other probe combinations.
Resumo:
Lamprophyre dykes have been recently discovered in blocks of gneiss embedded in a calcschist formation of wildflysch type that forms the top of the Mesozoic-Tertiary metasedimentary cover of the Antigorio nappe (the Teggiolo zone) in the Val Bavona (Lower Penninic, NW Ticino, Switzerland). The presence of the lamprophyres gives a clue to the possible source of these blocks. Similar dykes occur in the N part of the Maggia nappe where they are intruded into the Matorello granite and the surrounding gneisses. We studied these lamprophyres at two localities in the Teggiolo zone (Tamierpass and Lago del Zott) and at one locality in the Maggia nappe (Laghetti). Detailed mineralogical and geochemical investigations confirm their great similarity, particularly between the Tamier and Laghetti dykes. They all recrystallized during Alpine metamorphism under amphibolite facies conditions and lost their primary mineral assemblages and textures. The chemistry reveals a calc-alkaline affinity, a limited differentiation range, features of mineral accumulation and intense remobilization in some cases. The lamprophyres are characterized by a high mg# and relatively low contents in REE and other incompatible elements. In situ SHRIMP and LA-ICPMS U-Pb zircon dating yielded ages of 284.8 +/- 1.7 Ma (Tamier), 290.0 +/- 1.3 Ma (Zott) and 290.5 +/- 3.7 Ma (Laghetti). These ages are compatible with the general late- to post-Variscan magmatic evolution of the Helvetic and Lower Penninic domains. The lamprophyres are considered as melts derived from the lithospheric Variscan mantle, variously hybridized and differentiated at the contact with crustal material during late- to post-orogenic extension. These lamprophyres are chemically distinct from earlier lamprophyres of Visean age, emplaced together with their associated granites in transcurrent fault zones during the Variscan orogenic compression. The similarity of these different dykes suggests that the front of the Maggia nappe is a likely source of the gneissic blocks embedded in the calcschists at the top of the Teggiolo zone. They would have been provided by the advancing Maggia nappe during its thrusting over the Antigorio nappe and simultaneous closure of the Teggiolo sedimentary basin.
Resumo:
CD44 is the major cell-surface receptor for hyaluronan, which is implicated in cell-cell and cell-matrix adhesion, cell migration, and signaling. Studies have shown that CD44-dependent migration requires CD44 to be shed from the cell surface and that matrix metalloproteinase-mediated cleavage may provide an underlying mechanism. However, the full spectrum of proteases that may participate in CD44 shedding has yet to be defined. In this issue, Anderegg et al. demonstrate that ADAM10, but not ADAM17 or MMP14, mediates constitutive shedding of CD44 in human melanoma cells and that knockdown of ADAM10 blocks the antiproliferative activity of the soluble proteolytic cleavage product of CD44.
Resumo:
PURPOSE: Acute myeloid leukemia (AML) with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) [inv(3)/t(3;3)] is recognized as a distinctive entity in the WHO classification. Risk assignment and clinical and genetic characterization of AML with chromosome 3q abnormalities other than inv(3)/t(3;3) remain largely unresolved. PATIENTS AND METHODS: Cytogenetics, molecular genetics, therapy response, and outcome analysis were performed in 6,515 newly diagnosed adult AML patients. Patients were treated on Dutch-Belgian Hemato-Oncology Cooperative Group/Swiss Group for Clinical Cancer Research (HOVON/SAKK; n = 3,501) and German-Austrian Acute Myeloid Leukemia Study Group (AMLSG; n = 3,014) protocols. EVI1 and MDS1/EVI1 expression was determined by real-time quantitative polymerase chain reaction. RESULTS: 3q abnormalities were detected in 4.4% of AML patients (288 of 6,515). Four distinct groups were defined: A: inv(3)/t(3;3), 32%; B: balanced t(3q26), 18%; C: balanced t(3q21), 7%; and D: other 3q abnormalities, 43%. Monosomy 7 was the most common additional aberration in groups (A), 66%; (B), 31%; and (D), 37%. N-RAS mutations and dissociate EVI1 versus MDS1/EVI1 overexpression were associated with inv(3)/t(3;3). Patients with inv(3)/t(3;3) and balanced t(3q21) at diagnosis presented with higher WBC and platelet counts. In multivariable analysis, only inv(3)/t(3;3), but not t(3q26) and t(3q21), predicted reduced relapse-free survival (hazard ratio [HR], 1.99; P < .001) and overall survival (HR, 1.4; P = .006). This adverse prognostic impact of inv(3)/t(3;3) was enhanced by additional monosomy 7. Group D 3q aberrant AML also had a poor outcome related to the coexistence of complex and/or monosomal karyotypes and cryptic inv(3)/t(3;3). CONCLUSION: Various categories of 3q abnormalities in AML can be distinguished according to their clinical, hematologic, and genetic features. AML with inv(3)/t(3;3) represents a distinctive subgroup with unfavorable prognosis.