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排序方式: 共有1866条查询结果,搜索用时 125 毫秒
51.
Flavia M. Gonçalves Alisson Martins-Oliveira Riccardo Lacchini Vanessa A. Belo Jose G. Speciali Fabíola Dach Jose E. Tanus-Santos 《Gene》2013
Matrix metalloproteinases (MMP) are involved in the disruption of blood–brain barrier (BBB) during migraine attacks. In the present study, we hypothesized that two functional polymorphisms (C− 1306T and C− 735T) in MMP-2 gene and MMP-2 haplotypes are associated with migraine and modify MMP-2 and tissue inhibitor of MMP (TIMP)-2 levels in migraine. Genotypes for MMP-2 polymorphisms were determined by real time-PCR using Taqman allele discrimination assays. Haplotypes were inferred using the PHASE program. Plasma MMP-2 and TIMP-2 concentrations were measured by gelatin zymography and ELISA, respectively, in 148 healthy women without history of migraine and in 204 women with migraine (153 without aura; MWA, and 51 with aura; MA). Patients with MA had higher plasma MMP-2 concentrations and MMP-2/TIMP-2 ratios than patients with MWA and controls (P < 0.05). While MMP-2 genotype and haplotype distributions for the polymorphisms were similar among the groups (P > 0.05), we found that the CC genotype for C− 735T polymorphism and the CC haplotype were associated with higher plasma MMP-2 concentrations in MA group (P < 0.05). Our findings may help to understand the role of MMP-2 and its genetic variants in the pathophysiology of migraine and to identify a particular group of migraine patients with increased MMP-2 levels that would benefit from the use of MMP inhibitors. 相似文献
52.
Purpose
Overexpression of proto-oncogene HER-2 is one of the main molecular markers of breast cancer involved in prognosis and diagnosis and also in trastuzumab therapy. Thus, a request for the evaluation of HER-2 status in breast cancer has been increasing. The aim of our study was assessment of HER-2 overexpression in malignant and benign breast cancer specimens by Real Time RT-PCR technique and comparison of its results with IHC outcomes.Methods
Twenty benign and sixty malignant breast cancers in addition to fifteen normal breast tissue specimens were analyzed by Real Time RT-PCR method. Fresh tissue samples were disrupted by mortar and pestle. A syringe and a needle were used for complete homogenization of the tissues. The RNA was then isolated from the samples and converted to cDNA. A standard curve was initially plotted using BioEasy SYBR Green I and then all 95 specimens were studied by Real Time RT-PCR using 2− ΔΔCt method.Results
23.3% of 60 malignant specimens showed HER-2 overexpression, while all of the benign samples represented the normal expression level of HER-2 gene. The concordance rate between the results of Real Time RT-PCR and IHC was 86.6%.Conclusion
Real Time RT-PCR method is an almost reliable technique and at least can be used as a complementary method for confirming IHC results. This is emanated from relatively high rate of concordance between outcomes of IHC test, as a routine method of detecting the HER-2 gene expression status, and Real Time RT-PCR technique. 相似文献53.
Wafa Smaoui-Damak Feten Guebsi Sahar Karray Tarak Rebai Katherine Costil Amel Hamza-Chaffai 《Invertebrate reproduction & development.》2013,57(4):261-271
In this study, the variations of glycogen concentrations in Ruditapes decussatus from Sfax coasts (Tunisia) were described in relation to the reproductive cycle. Separate analyses were made of gonad, adductor muscle and ‘remainder’. The timing of gametogenic development and spawning was evaluated using qualitative histology associated with image analysis including (1) the estimation of the gonadal occupation index (GOI), (2) surface area occupied by reserve tissues and (3) variation in oocyte diameter. The reproductive cycle of R. decussatus exhibited partial asynchronization between sexes, the major difference being observed in the duration of the spawning period. Contrary to previous studies, we observed continuous partial spawning (e.g. 50% of ripe oocytes still subsisted at the partial spawning stage). During the gametogenic cycle, GOI varied significantly in males and in females. Most oocytes were ripe and ready to spawn when their diameter reached or exceeded 45?µm. The expansion of gonad was inversely proportional to the development of the foot tissue. Glycogen concentration showed significant temporal variations between tissues, indicating the clear differentiation in energy storage between the clam organs. 相似文献
54.
Close‐up underwater photography and image analysis were used to quantify mesh occlusion by biofouling of salmon‐cage netting. This technique allows fast, non‐destructive sampling of cages in situ for the determination of temporal and spatial changes in fouling. The area of net blockage can be easily determined, allowing rapid evaluation of cleaning or antifouling performance. 相似文献
55.
Bacterial biofilms adapt and shape their structure in response to varied environmental conditions. A statistical methodology was adopted in this study to empirically investigate the influence of nutrients on biofilm structural parameters deduced from confocal scanning laser microscope images of Paracoccus sp.W1b, a denitrifying bacterium. High concentrations of succinate, Mg++, Ca++, and Mn++ were shown to enhance biofilm formation whereas higher concentration of iron decreased biofilm formation. Biofilm formed at high succinate was uneven with high surface to biovolume ratio. Higher Mg++ or Ca++ concentrations induced cohesion of biofilm cells, but contrasting biofilm architectures were detected. Biofilm with subpopulation of pillar-like protruding cells was distributed on a mosaic form of monolayer cells in medium with 10 mM Mg++. 10 mM Ca++ induced a dense confluent biofilm. Denitrification activity was significantly increased in the Mg++- and Ca++-induced biofilms. Chelator treatment of various biofilm ages indicated that divalent cations are important in the initial stages of biofilm formation. 相似文献
56.
57.
Sébastien Tisné Yann Serrand Liên Bach Elodie Gilbault Rachid Ben Ameur Hervé Balasse Roger Voisin David Bouchez Mylène Durand‐Tardif Philippe Guerche Gaël Chareyron Jérôme Da Rugna Christine Camilleri Olivier Loudet 《The Plant journal : for cell and molecular biology》2013,74(3):534-544
Increased phenotyping accuracy and throughput are necessary to improve our understanding of quantitative variation and to be able to deconstruct complex traits such as those involved in growth responses to the environment. Still, only a few facilities are known to handle individual plants of small stature for non‐destructive, real‐time phenotype acquisition from plants grown in precisely adjusted and variable experimental conditions. Here, we describe Phenoscope, a high‐throughput phenotyping platform that has the unique feature of continuously rotating 735 individual pots over a table. It automatically adjusts watering and is equipped with a zenithal imaging system to monitor rosette size and expansion rate during the vegetative stage, with automatic image analysis allowing manual correction. When applied to Arabidopsis thaliana, we show that rotating the pots strongly reduced micro‐environmental disparity: heterogeneity in evaporation was cut by a factor of 2.5 and the number of replicates needed to detect a specific mild genotypic effect was reduced by a factor of 3. In addition, by controlling a large proportion of the micro‐environmental variance, other tangible sources of variance become noticeable. Overall, Phenoscope makes it possible to perform large‐scale experiments that would not be possible or reproducible by hand. When applied to a typical quantitative trait loci (QTL) mapping experiment, we show that mapping power is more limited by genetic complexity than phenotyping accuracy. This will help to draw a more general picture as to how genetic diversity shapes phenotypic variation. 相似文献
58.
Ajay Narendra Sarah Gourmaud Jochen Zeil 《Proceedings. Biological sciences / The Royal Society》2013,280(1765)
Ants are efficient navigators, guided by path integration and visual landmarks. Path integration is the primary strategy in landmark-poor habitats, but landmarks are readily used when available. The landmark panorama provides reliable information about heading direction, routes and specific location. Visual memories for guidance are often acquired along routes or near to significant places. Over what area can such locally acquired memories provide information for reaching a place? This question is unusually approachable in the solitary foraging Australian jack jumper ant, since individual foragers typically travel to one or two nest-specific foraging trees. We find that within 10 m from the nest, ants both with and without home vector information available from path integration return directly to the nest from all compass directions, after briefly scanning the panorama. By reconstructing panoramic views within the successful homing range, we show that in the open woodland habitat of these ants, snapshot memories acquired close to the nest provide sufficient navigational information to determine nest-directed heading direction over a surprisingly large area, including areas that animals may have not visited previously. 相似文献
59.
Mangshan pitviper, Protobothrops mangshanensis(formerly Zhaoermia mangshanensis) is endemic to China. Unfortunately, due to the decreasing size of its wild populations, this snake has been listed as critically endangered. Research carried out on the Mangshan pitviper's population ecology and captive reproduction has revealed that the unique head patch patterns of different individuals may potentially be used as a noninvasive recognition biometric character. We collected head patch pattern images of 40 individuals of P. mangshanensis between 1994 and 2011. By comparing each pitviper's head patch pattern, we found that the head patch pattern of individual snakes was different and unique. Additionally, we observed and recorded the head patch pattern characters of four adults and five juveniles before and after ecdysis. Our findings confirmed that head patch patterns of Mangshan pitvipers are unique and stable, remaining unchanged after ecdysis. Thus, individuals can be quickly identified by examining the head patch pattern within a specific recognition area on the head. This method may be useful for noninvasive individual recognition in many other species that display color patch pattern variations, especially in studies of endangered species where the use of invasive marking techniques is undesirable. 相似文献
60.
Hashem Kalbkhani Mahrokh G. Shayesteh Behrooz Zali-Vargahan 《Biomedical signal processing and control》2013,8(6):909-919
In this paper, a robust algorithm for disease type determination in brain magnetic resonance image (MRI) is presented. The proposed method classifies MRI into normal or one of the seven different diseases. At first two-level two-dimensional discrete wavelet transform (2D DWT) of input image is calculated. Our analysis show that the wavelet coefficients of detail sub-bands can be modeled by generalized autoregressive conditional heteroscedasticity (GARCH) statistical model. The parameters of GARCH model are considered as the primary feature vector. After feature vector normalization, principal component analysis (PCA) and linear discriminant analysis (LDA) are used to extract the proper features and remove the redundancy from the primary feature vector. Finally, the extracted features are applied to the K-nearest neighbor (KNN) and support vector machine (SVM) classifiers separately to determine the normal image or disease type. Experimental results indicate that the proposed algorithm achieves high classification rate and outperforms recently introduced methods while it needs less number of features for classification. 相似文献