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71.
Amilcar Chagas Freitas Júnior Paulo Henrique dos Santos Ching-Chang Ko Manoel Martín Júnior Erika Oliveira de Almeida 《Computer methods in biomechanics and biomedical engineering》2013,16(5):515-521
This study aimed to evaluate the influence of loading on a maxillary central incisor with the periodontal ligament (PDL) represented by 2D elastic beam elements using a 2D finite element analysis. Two models (M) were built varying the PDL representation: Mh (homogeneous PDL) and Mht (heterogeneous PDL with beam3 elements). Stress and displacements were determined for three loading conditions (L): Ll, lingual face loading at 45° with the tooth long axis; Li, perpendicular to the incisal edge; and Lip, on the incisal edge, parallel to the tooth long axis. Evaluation was performed on ANSYS software. Lip provided lower stress variation on the tooth and support structures when compared to Ll and Li. PDL's influence on stress values was lower for Lip. Oblique loading showed stress and displacement not observed in parallel loading condition through PDL's heterogeneous representation and it is probably incompatible with the in vivo condition. 相似文献
72.
Patrícia M. Domingues António Louvado Vanessa Oliveira Francisco J. C. R. Coelho Adelaide Almeida Newton C. M. Gomes 《Preparative biochemistry & biotechnology》2013,43(3):237-255
The potential of estuarine microniches as reservoirs of biosurfactant-producing bacteria was evaluated by testing different combinations of inocula and hydrophobic carbon sources. Selective cultures using diesel, petroleum, or paraffin as hydrophobic carbon sources were prepared and inoculated with water from the surface microlayer, bulk sediments, and sediment of the rhizosphere of Halimione portulacoides. These inocula were compared regarding the frequency of biosurfactant-producing strains among selected isolates. The community structure of the selective cultures was profiled using denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA gene fragments at the end of the incubation. The DGGE profiles corresponding to the communities established in selective cultures at the end of the incubation revealed that communities were different in terms of structural diversity. The highest diversity was observed in the selective cultures containing paraffin (H ' = 2.5). Isolates were obtained from the selective cultures (66) and tested for biosurfactant production by the atomized oil assay. Biosurfactant production was detected in 17 isolates identified as Microbacterium, Pseudomonas, Rhodococcus, and Serratia. The combination of estuarine surface microlayer (SML) water as inoculum and diesel as carbon source seems promising for the isolation of surfactant-producing bacteria. Supplemental materials are available for this article. Go to the publisher's online edition of Preparative Biochemistry and Biotechnology to view the supplemental file. 相似文献
73.
Alice Simon Vinícius Raphael de Almeida Borges Lucio Mendes Cabral Valéria Pereira de Sousa 《AAPS PharmSciTech》2013,14(1):425-434
The intramuscular administration of the injectable suspension betamethasone sodium phosphate (BSP) and betamethasone dipropionate (BD) has immediate therapeutic activity due to solubilized BSP and prolonged activity resulting from the slow release of BD micro-crystals. The purpose of this study was to develop and validate a dissolution method for BD in intramuscular injectable suspensions with detection by high-performance liquid chromatography (HPLC) method. Five commercial products presented a distribution of particle sizes, ranging between 7.43 and 40.25 μm as measured by laser diffraction. It was also found that particle sizes differed between batches of the same product. The different products were tested using the paddle apparatus, with stirring speeds of 25 and 50 rpm in 300 mL of phosphate buffer; simulated body fluid, muscle fluid, and synovial fluid were used as biorelevant dissolution media at 37 ± 0.5°C. It was verified that not only does average particle size affect the dissolution rate, but also the mode and the polydispersity index of the particles. Discriminatory power was obtained using the in vitro dissolution method with 0.1 M sodium phosphate buffer pH 7.4 containing 0.1% sodium lauryl sulfate and a stirring speed of 50 rpm. The HPLC-method is linear, precise, selective, and accurate for the quantification of BSP and BD in dissolution profile testing. This dissolution method can be utilized as a method to control the quality of these injectable suspensions.Key words: dipropionate betamethasone, dissolution test, intramuscular injectable suspensions, simulated muscular fluid, sodium phosphate betamethasone 相似文献
74.
Adriana R. Rodrigues Henrique Almeida Alexandra M. Gouveia 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2013,1831(7):1267-1275
The melanocortin system has a clear effect on the mobilisation of stored lipids in adipocytes. The aim of the current study was to investigate the role of melanocortin 5 receptor (MC5R) on α-melanocyte-stimulating hormone (α-MSH)-induced lipolysis in 3T3-L1 adipocytes. To this end, MC5R expression was decreased by small interfering RNA (siRNA), which significantly impaired the α-MSH stimulation of lipolysis, as determined by glycerol and nonesterified fatty-acid (NEFA) quantification. The functional role of α-MSH/MC5R on triglyceride (TG) hydrolysis was mediated by hormone-sensitive lipase (HSL), adipose triglyceride lipase (ATGL), perilipin 1 (PLIN1) and acetyl-CoA carboxylase (ACC). Immunofluorescence microscopy revealed that phosphorylated HSL clearly surrounded lipid droplets in α-MSH-stimulated adipocytes, whereas PLIN1 left the immediate periphery of lipids. These observations were lost when the expression of MC5R was suppressed. 相似文献
75.
Sara Violante Lodewijk IJlst Heleen te Brinke Janet Koster Isabel Tavares de Almeida Ronald J.A. Wanders Fátima V. Ventura Sander M. Houten 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2013,1831(9):1467-1474
Fatty acid β-oxidation may occur in both mitochondria and peroxisomes. While peroxisomes oxidize specific carboxylic acids such as very long-chain fatty acids, branched-chain fatty acids, bile acids, and fatty dicarboxylic acids, mitochondria oxidize long-, medium-, and short-chain fatty acids. Oxidation of long-chain substrates requires the carnitine shuttle for mitochondrial access but medium-chain fatty acid oxidation is generally considered carnitine-independent. Using control and carnitine palmitoyltransferase 2 (CPT2)- and carnitine/acylcarnitine translocase (CACT)-deficient human fibroblasts, we investigated the oxidation of lauric acid (C12:0). Measurement of the acylcarnitine profile in the extracellular medium revealed significantly elevated levels of extracellular C10- and C12-carnitine in CPT2- and CACT-deficient fibroblasts. The accumulation of C12-carnitine indicates that lauric acid also uses the carnitine shuttle to access mitochondria. Moreover, the accumulation of extracellular C10-carnitine in CPT2- and CACT-deficient cells suggests an extramitochondrial pathway for the oxidation of lauric acid. Indeed, in the absence of peroxisomes C10-carnitine is not produced, proving that this intermediate is a product of peroxisomal β-oxidation. In conclusion, when the carnitine shuttle is impaired lauric acid is partly oxidized in peroxisomes. This peroxisomal oxidation could be a compensatory mechanism to metabolize straight medium- and long-chain fatty acids, especially in cases of mitochondrial fatty acid β-oxidation deficiency or overload. 相似文献
76.
In vivo effects of two sublethal doses of chlorpyrifos and carbaryl were studied in Procambarus clarkii after 2 and 7 days of exposure, and after pesticide removal. Chlorpyrifos inhibited carboxylesterase activity in a concentration-dependent manner, but acetylcholinesterase was less sensitive. Compared with chlorpyrifos, carbaryl had a less marked effect on esterase activity. The effects of selected pesticides on biotransformation or oxidative stress biomarkers were contradictory. Chlorpyrifos lowered ethoxyresorufin-O-deethylase (EROD), catalase and oxidized glutathione (GSSG) levels but raised glutathione-S-transferase activity, while carbaryl raised EROD, catalase and glutathione-S-transferase, but lowered glutathione peroxidase and reduced glutathione (GSH) levels. The effects on protein expression patterns depending on pesticide type and the tissue used for analysis were studied in parallel by 2-DE. In gill and nervous tissue about 2000 spots (pI 4–7) were resolved, with quite different expression patterns. Chlorpyrifos altered 72 proteins, mostly in nervous tissue, and carbaryl 35, distributed evenly between organs. Several specific spots were selected as specific protein expression signatures for chlorpyrifos or carbaryl exposure in gills and nervous tissue, respectively. 相似文献
77.
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79.
Zhijun Zhang Sandra Almeida Yubing Lu Agnes L. Nishimura Lingtao Peng Danqiong Sun Bei Wu Anna M. Karydas Maria C. Tartaglia Jamie C. Fong Bruce L. Miller Robert V. Farese Jr Melissa J. Moore Christopher E. Shaw Fen-Biao Gao 《PloS one》2013,8(10)
Transactive response DNA-binding protein 43 (TDP-43) is a major pathological protein in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). There are many disease-associated mutations in TDP-43, and several cellular and animal models with ectopic overexpression of mutant TDP-43 have been established. Here we sought to study altered molecular events in FTD and ALS by using induced pluripotent stem cell (iPSC) derived patient neurons. We generated multiple iPSC lines from an FTD/ALS patient with the TARDBP A90V mutation and from an unaffected family member who lacked the mutation. After extensive characterization, two to three iPSC lines from each subject were selected, differentiated into postmitotic neurons, and screened for relevant cell-autonomous phenotypes. Patient-derived neurons were more sensitive than control neurons to 100 nM straurosporine but not to other inducers of cellular stress. Three disease-relevant cellular phenotypes were revealed under staurosporine-induced stress. First, TDP-43 was localized in the cytoplasm of a higher percentage of patient neurons than control neurons. Second, the total TDP-43 level was lower in patient neurons with the A90V mutation. Third, the levels of microRNA-9 (miR-9) and its precursor pri-miR-9-2 decreased in patient neurons but not in control neurons. The latter is likely because of reduced TDP-43, as shRNA-mediated TDP-43 knockdown in rodent primary neurons also decreased the pri-miR-9-2 level. The reduction in miR-9 expression was confirmed in human neurons derived from iPSC lines containing the more pathogenic TARDBP M337V mutation, suggesting miR-9 downregulation might be a common pathogenic event in FTD/ALS. These results show that iPSC models of FTD/ALS are useful for revealing stress-dependent cellular defects of human patient neurons containing rare TDP-43 mutations in their native genetic contexts. 相似文献
80.
Caio Cesar de Souza Alves Adam Collison Luke Hatchwell Maximilian Plank Matthew Morten Paul S. Foster Sebastian L. Johnston Cristiane Fran?a da Costa Mauro Vieira de Almeida Henrique Couto Teixeira Ana Paula Ferreira Joerg Mattes 《PloS one》2013,8(11)