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981.
Aubin CE Labelle H Cheriet F Villemure I Mathieu PA Dansereau J 《Médecine sciences : M/S》2007,23(11):904-909
Adolescent idiopathic scoliosis involves complex tridimensional deformities of the spine, rib cage and pelvis. Moderate curves generally are treated using an orthosis. This paper presents different studies performed over the last fifteen years related to the biomechanical evaluation and optimization of the orthopedic treatment of scoliotic deformities. Patient specific 3D models of the spine, pelvis and rib cage are computed from calibrated radiographs, and are used to calculate 2D and 3D clinical indices. The torso shape is acquired using surface topography. With such internal and external 3D models, the efficacy of the most frequently used orthoses can be analyzed and new treatments can be developed. Pressures generated by a brace on the patient's trunk were measured using a flexible matrix of pressure sensors and displayed over the patient's internal geometry in order to analyze the brace efficacy. Patient specific finite element models have been developed, including the osseo-ligamentous structures as well as the muscles, the neuro-control, trunk growth and its adaptation to the stress. These models were used to analyze the effects of the Boston brace. The electro-myographic activity also was measured to analyze the < active > correction mechanisms. Adjustment techniques and software are used to help the orthotists with real time feedback when the brace is being fabricated and adjusted to the patient. Residual growth potential is also being added to the computer model to simulate the long term effect of a brace. The improvement of the orthotic treatments of scoliotic deformities is very encouraging. The exploitation of such tools is expected to allow reaching optimal treatment personalized to each patient. double dagger. 相似文献
982.
Ramprasad OG Srinivas G Rao KS Joshi P Thiery JP Dufour S Pande G 《Cell motility and the cytoskeleton》2007,64(3):199-216
The number and distribution of lipid molecules, including cholesterol in particular, in the plasma membrane, may play a key role in regulating several physiological processes in cells. We investigated the role of membrane cholesterol in regulating cell shape, adhesion and motility. The acute depletion of cholesterol from the plasma membrane of cells that were well spread and motile on fibronectin caused the rounding of these cells and decreased their adhesion to and motility on fibronectin. These modifications were less pronounced in cells plated on laminin, vitronectin or plastic, indicating that cholesterol-mediated changes in adhesion and motility are more specific for adhesion mediated by fibronectin-specific integrins, such as alpha5beta1. These changes were accompanied by remodeling of the actin cytoskeleton, the spatial reorganization of paxillin in the membrane, and changes to the dynamics of alpha5 integrin and paxillin-rich focal adhesions. Levels of tyrosine phosphorylation at position 576/577 of FAK and Erk1/Erk2 MAP-kinase activity levels were both lower in cholesterol-depleted than in control cells. These levels normalized only on fibronectin when cholesterol was reincorporated into the cell membrane. Thus, membrane cholesterol content has a specific effect on certain signaling pathways specifically involved in regulating cell motility on fibronectin and organization of the actin cytoskeleton. 相似文献
983.
Lamesch P Li N Milstein S Fan C Hao T Szabo G Hu Z Venkatesan K Bethel G Martin P Rogers J Lawlor S McLaren S Dricot A Borick H Cusick ME Vandenhaute J Dunham I Hill DE Vidal M 《Genomics》2007,89(3):307-315
Complete sets of cloned protein-encoding open reading frames (ORFs), or ORFeomes, are essential tools for large-scale proteomics and systems biology studies. Here we describe human ORFeome version 3.1 (hORFeome v3.1), currently the largest publicly available resource of full-length human ORFs (available at ). Generated by Gateway recombinational cloning, this collection contains 12,212 ORFs, representing 10,214 human genes, and corresponds to a 51% expansion of the original hORFeome v1.1. An online human ORFeome database, hORFDB, was built and serves as the central repository for all cloned human ORFs (http://horfdb.dfci.harvard.edu). This expansion of the original ORFeome resource greatly increases the potential experimental search space for large-scale proteomics studies, which will lead to the generation of more comprehensive datasets. 相似文献
984.
985.
Molin M Renault JP Lagniel G Pin S Toledano M Labarre J 《Free radical biology & medicine》2007,43(1):136-144
Repair of DNA damage is fundamental for cellular tolerance to ionizing radiation (IR) and many IR-induced DNA lesions are thought to occur as a result of oxidative stress. We investigated the physiological effects of IR in Saccharomyces cerevisiae by performing protein expression profiles in cells exposed to electron pulse irradiation. Transient induction of several antioxidant enzymes in wild-type cells, but not in cells lacking the oxidative stress regulator Yap1, indicated that IR exposure causes cellular oxidative stress. Yap1 activation involved oxidation to the intramolecular disulfide bond, a signature of activation by peroxide, and was dependent on the Yap1 peroxide sensor Orp1/Gpx3. H(2)O(2) was produced in the culture medium of irradiated cells and was both necessary and sufficient for IR-induced Yap1 activation. When IR was performed in the presence of N(2)O, obviating H(2)O(2) production and increasing hydroxyl radical ((*)OH) production, the Yap1 response was lost, indicating that Yap1 was unable to respond to (*)OH or (*)OH-induced damage. However, the Yap1 response to IR did not seem to be a primary determinant of cellular IR tolerance. Altogether, these data provide a molecular demonstration that cells experience in vivo peroxide stress during IR and indicate that the H(2)O(2) produced cannot account for IR toxicity. 相似文献
986.
González R Collado JA Nell S Briceño J Tamayo MJ Fraga E Bernardos A López-Cillero P Pascussi JM Rufián S Vilarem MJ De la Mata M Brigelius-Flohe R Maurel P Muntané J 《Free radical biology & medicine》2007,43(10):1439-1452
Vitamin E (alpha-tocopherol) has demonstrated antioxidant activity and gene-regulatory properties. d-Galactosamine (D-GalN)-induced cell death is mediated by nitric oxide in hepatocytes, and it is associated with hepatic steatosis. The beneficial properties of alpha-tocopherol and their relation to oxidative stress and gene regulation were assessed in D-GalN-induced cell death. Hepatocytes were isolated from human liver resections by a collagenase perfusion technique. alpha-Tocopherol (50 microM) was administered at the advanced stages (10 h) of D-GalN-induced cell death in cultured hepatocytes. Cell death, oxidative stress, alpha-tocopherol metabolism, and NF-kappaB-, pregnane X receptor (PXR)-, and peroxisome proliferator-activated receptor (PPAR-alpha)-associated gene regulation were estimated in the hepatocytes. D-GalN increased cell death and alpha-tocopherol metabolism. alpha-Tocopherol exerted a moderate beneficial effect against apoptosis and necrosis induced by D-GalN. Induction (rifampicin) or inhibition (ketoconazole) of alpha-tocopherol metabolism and overexpression of PXR showed that the increase in PXR-related CYP3A4 expression caused by alpha-tocopherol enhanced cell death in hepatocytes. Nevertheless, the reduction in NF-kappaB activation and inducible nitric oxide synthase expression and the enhancement of PPAR-alpha and carnitine palmitoyl transferase gene expression by alpha-tocopherol may be relevant for cell survival. In conclusion, the cytoprotective properties of alpha-tocopherol are mostly related to gene regulation rather than to antioxidant activity in toxin-induced cell death in hepatocytes. 相似文献
987.
Diversity of arbuscular mycorrhizal fungi (AMF) was assessed in two 9.2 × 9.2-m plots planted with landscape trees and shrubs
at an experimental site in Phoenix, AZ, USA. Twenty-five soil samples were collected in a regular grid pattern from each plot,
and AMF species were identified using trap cultures. A total of 12 species were detected, with 7 species detected in one plot
and 11 in the other. We found that sampling effort had a major impact on assessing species richness and composition in this
local community. Fifteen samples would be necessary to detect 70–80% of species present in each plot. A limited number of
additional undetected species are likely to be present in both plots, based on the sampling effort curves and jackknife estimates.
Only two species, Glomus eburneum and Glomus microaggregatum, were detected in over 50% of the samples from both plots, and rank–frequency plots revealed a lognormal species distribution.
Despite the patchiness of plants in the plots, the number of species detected per point exhibited spatial structuring only
at the smallest sampling scale in a single plot, and only a single species in each plot was not randomly distributed. These
results indicate that sampling effort and strategy can affect perceptions of AMF community structure. 相似文献
988.
Functional characterization of both MAP kinases of the human malaria parasite Plasmodium falciparum by reverse genetics 总被引:2,自引:0,他引:2
Dorin-Semblat D Quashie N Halbert J Sicard A Doerig C Peat E Ranford-Cartwright L Doerig C 《Molecular microbiology》2007,65(5):1170-1180
The kinome of the human malaria parasite Plasmodium falciparum includes two genes encoding mitogen-activated protein kinase (MAPK) homologues, pfmap-1 and pfmap-2, but no clear orthologue of the MAPK kinase (MAPKK) family, raising the question of the mode of activation and function of the plasmodial MAPKs. Functional studies in the rodent malaria model Plasmodium berghei recently showed the map-2 gene to be dispensable for asexual growth and gametocytogenesis, but essential for male gametogenesis in the mosquito vector. Here, we demonstrate by using a reverse genetics approach that the map-2 gene is essential for completion of the asexual cycle of P. falciparum, an unexpected result in view of the non-essentiality of the orthologous gene for P. berghei erythrocytic schizogony. This validates Pfmap-2 as a potential target for chemotherapeutic intervention. In contrast, the other P. falciparum MAPK, Pfmap-1, is required neither for in vitro schizogony and gametocytogenesis in erythrocytes, nor for gametogenesis and sporogony in the mosquito vector. However, Pfmap-2 protein levels are elevated in pfmap-1(-) parasites, suggesting that Pfmap-1 fulfils an important function in asexual parasites that necessitates compensatory adaptation in parasites lacking this enzyme. 相似文献
989.
Aude Vialatte Manuel Plantegenest Jean‐Christophe Simon Charles‐Antoine Dedryver 《Agricultural and Forest Entomology》2007,9(4):337-346
1 Integrated management of crop pests requires the identification of the appropriate spatial scale at which colonization processes occurs. We assessed, by coupling demographic and genetic methods, the relative contribution of local and transient migrants of the grain aphid Sitobion avenae to wheat field colonization in spring. 2 We examined, during two consecutive years, the daily colonization of wheat by aphid migrants and compared this with daily aphid flight monitored by a local 12.2‐m suction trap. The genetic profiles of aphids landing on crops were compared with those of both flying aphids caught by the suction trap and local populations from arable crops and hedgerows. 3 In the first year, we observed: (i) a strong correlation between aphids colonizing the crop and those moving within the crop and a close genetic similarity between aphids from these samples and (ii) a high level of genetic differentiation between these aphids and populations from local cereals and field margins. In the second year, the number of migrants recorded on the wheat was three‐fold higher than in the previous year, and less correlated with that recorded by the suction trap. This was associated with a lack of genetic differentiation between all samples. 4 This variation in the colonization processes resulted mainly in an abrupt increase in abundance of genotypes from local over‐wintering sites in 2004. This suggests that, despite the long range dispersal potential of the grain aphid, outbreak risks could be mainly determined at a local scale, encouraging the design of relatively small management units. 相似文献
990.
Jean Carlos Budke João André Jarenkow Ary Teixeira de Oliveira-Filho 《Plant Ecology》2007,189(2):187-200
The relationships among floristic, structural and physiognomic variables of the tree component, flooding regime variations
and soil fertility were investigated in a riparian forest fragment (ca. 43 ha) in the Rio Botucaraí watershed near the confluence
with the Rio Jacuí, southern Brazil. All the trees with a dbh ≥ 15 cm were surveyed in 100 contiguous 10 × 10 m plots
and soil chemical and textural variables were obtained from the analyses of 15 topsoil samples (0–20 cm depth) collected at
different locations. The sample sites encompass all the topographic variation of the area. We used canonical correspondence
analysis (CCA) to seek correlations between environmental variables and tree component distribution. The 1,547 surveyed individuals
belonged to 30 species and 16 botanical families. The Shannon diversity index (H′) and the Pielou equability (J′) were 1.995
and 0.586 nats ind.−1, respectively. Sebastiania commersoniana, Casearia sylvestris, Eugenia uniflora and Eugenia hyemalis presented the highest importance values. Species’ densities chiefly correlated with site elevation, flooding regime and soil
chemical fertility. The analyses of ecological categories (EC) revealed that most species are heliophylous and typical of
early successional stages. Richness and diversity (P < 0.001) variations from different topographic positions reflect that at the local scale, flooding was a limiting factor
for the establishment of certain species suggesting that local processes control species richness and diversity. 相似文献