992 resultados para orientamento :: 481 :: Scelta guidata 2 (sistemi e segnali biologici)
Resumo:
Large, osseous, segmental defects heal poorly. Muscle has a propensity to form bone when exposed to an osteogenic stimulus such as that provided by transfer and expression of cDNA encoding bone morphogenetic protein-2 (BMP-2). The present study evaluated the ability of genetically modified, autologous muscle to heal large cranial defects in rats. Autologous grafts (8 mm � 2 mm) were punched from the biceps femoris muscle and transduced intraoperatively with recombinant adenovirus vector containing human BMP-2 or green fluorescent protein cDNA. While the muscle biopsies were incubating with the vector, a central parietal 8 mm defect was surgically created in the calvarium of the same animal. The gene-activated muscle graft was then implanted into the cranial defect. After 8 weeks, crania were examined radiographically, histologically, and by micro-computed tomography and dual energy X-ray absorptiometry. Although none of the defects were completely healed in this time, muscle grafts expressing BMP-2 deposited more than twice as much new bone as controls. Histology confirmed the anatomical integrity of the newly formed bone, which was comparable in thickness and mineral density to the original cranial bone. This study confirms the in vivo osteogenic properties of genetically modified muscle and suggests novel strategies for healing bone. � 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1095–1102, 2012
Resumo:
This study reports that treatment of osseous defects with different growth factors initiates distinct rates of repair. We developed a new method for monitoring the progression of repair, based upon measuring the in vivo mechanical properties of healing bone. Two different members of the bone morphogenetic protein (BMP) family were chosen to initiate defect healing: BMP-2 to induce osteogenesis, and growth-and-differentiation factor (GDF)-5 to induce chondrogenesis. To evaluate bone healing, BMPs were implanted into stabilised 5 mm bone defects in rat femurs and compared to controls. During the first two weeks, in vivo biomechanical measurements showed similar values regardless of the treatment used. However, 2 weeks after surgery, the rhBMP-2 group had a substantial increase in stiffness, which was supported by the imaging modalities. Although the rhGDF-5 group showed comparable mechanical properties at 6 weeks as the rhBMP-2 group, the temporal development of regenerating tissues appeared different with rhGDF-5, resulting in a smaller callus and delayed tissue mineralisation. Moreover, histology showed the presence of cartilage in the rhGDF-5 group whereas the rhBMP-2 group had no cartilaginous tissue. Therefore, this study shows that rhBMP-2 and rhGDF-5 treated defects, under the same conditions, use distinct rates of bone healing as shown by the tissue mechanical properties. Furthermore, results showed that in vivo biomechanical method is capable of detecting differences in healing rate by means of change in callus stiffness due to tissue mineralisation.
Resumo:
Objective To determine whether locally applied tobramycin influences the ability of recombinant human bone morphogenetic protein 2 (rhBMP-2) to heal a segmental defect in the rat femur. Methods The influence of tobramycin on the osteogenic differentiation of mesenchymal stem cells was first evaluated in vitro. For the subsequent, in vivo experiments, a 5-mm segmental defect was created in the right femur of each of 25 Sprague-Dawley rats and stabilized with an external fixator and four Kirschner wires. Rats were divided in four groups: empty control, tobramycin (11 mg)/absorbable collagen sponge, rhBMP-2 (11 μg)/absorbable collagen sponge, and rhBMP-2/absorbable collagen sponge with tobramycin. Bone healing was monitored by radiography at 3 and 8 weeks. Animals were euthanized at 8 weeks and the properties of the defect were compared with the intact contralateral femur. Bone formation in the defect region was assessed by dual-energy x-ray absorptiometry, microcomputed tomography, histology, and mechanical testing. Results Tobramycin exerted a dose-dependent inhibition of alkaline phosphatase induction and calcium deposition by mesenchymal stem cells cultured under osteogenic conditions. The inhibition was reversed in the presence of 500 ng/mL of rhBMP-2. Segmental defects in the rat femora failed to heal in the absence of rhBMP-2. Tobramycin exerted no inhibitory effects on the ability of rhBMP-2 to heal these defects and increased the bone area of the defects treated with rhBMP-2. Data obtained from all other parameters of healing, including dual-energy x-ray absorptiometry, microcomputed tomography, histology, and mechanical testing, were unaffected by tobramycin. Conclusions Although our in vitro results suggested that tobramycin inhibits the osteogenic differentiation of mesenchymal stem cells, this could be overcome by rhBMP-2. Tobramycin did not impair the ability of rhBMP-2 to heal critical-sized femoral defects in rats. Indeed, bone area was increased by nearly 20% in the rhBMP-2 group treated with tobramycin. This study shows that locally applied tobramycin can be used in conjunction with rhBMP-2 to enhance bone formation at fracture sites.
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In the structure of the title salt C7H10NO+ C8H3Cl2O4- the benzene planes of the cation and anion are essentially parallel [inter-ring dihedral angle 4.8(2)deg]. In the anion the carboxylic acid and carboxylate groups make dihedral angles of 19.0(2) and 79.5(2)\%, respectively, with the benzene ring. Aminium N-H...O, carboxylic acid O-H...O and weak aromatic C-H...O hydrogen-bonding associations with carboxyl O-atom acceptors together with cation-anion pi-pi ring interactions [minimum ring centroid separation = 3.734(3)Ang] give a two-dimensional sheet structure which lies parallel to (001).
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In the structure of the title complex [Cs(C8H4Cl3O2)(H2O)]n, the Cs salt of the commercial herbicide fenac [(2,3,6-trichlorophenyl)acetic acid], the irregular eight-coordination about Cs+ comprises a bidentate chelate (O:Cl) interaction involving a carboxyl O-atom and an ortho-related ring substituted Cl atom which is also bridging, a triple-bridging carboxyl O-atom and a bridging water molecule. A two-dimensional sheet polymer is generated, lying parallel to (100), within which there are water O---H...O(carboxyl) hydrogen-bonding interactions.
Resumo:
In the title compound, [K2(C7H3Cl2O2)2(H2O)]n, the potassium salt of 2,4-dichlorobenzoic acid, the repeating unit in the polymeric structure consists of two identical irregular KO6Cl complex units related by twofold rotational symmetry, linked by a bridging water molecule lying on the twofold axis. The coordination polyhedron about each K+ comprises a carboxyl O-atom and a Cl-atom donor from a bidentate chelate ligand interaction, four O-atom donors from a doubly bridging bidentate carboxyl (O,O')-chelate interaction and the water molecule. A two-dimensional layered coordination polymer structure lying parallel to (100) is generated through a series of conjoined cyclic bridges between K centres and is stabilized by water O-H...O(carboxyl) hydrogen-bonding interactions.
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In the structure of title compound [Rb2(C7H5N2O4)2(H2O)2]n the asymmetric unit comprises two independent and different seven-coordinate Rb centres, one RbO7, the other RbO6N, with both having irregular stereochemistry. The RbO7 coordination comprises bridging oxygen donors from two water molecules, three carboxylate groups, and a nitro group, with one doubly bridging. The RbO6N coordination comprises the two bridging water molecules, one monodentate amine N donor, one carboxyl O donor and three O donors from nitro groups (one from the chelate bridge). The extension of the dinuclear unit gives a three-dimensional polymeric structure which is stabilized by both intra- and intermolecular amine N-H...O and water O-H...O hydrogen bonds to carboxyl and water O-atom acceptors, as well as a number of inter-ring \p--\p interactions [minimum ring centroid separation, 3.364(2) \%A]. This complex is both isostructural with the analogous Cs -nitroanthranilate monohydrate complex.
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Australian law similar to that of United States -- Australian law requires copyright must subsist in plaintiff's material and defendent's work must infringe plaintiff's copyright to find defendent liable for illegal copying -- subsistence -- infringement -- two cases that touch on 'look and feel' issue -- passing-off -- look and feel of computer program deserves protection
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The aim of this study was to use lipidomics to determine if the lipid composition of apolipoprotein-B-containing lipoproteins is modified by dyslipidaemia in type 2 diabetes and if any of the identified changes potentially have biological relevance in the pathophysiology of type 2 diabetes. VLDL and LDL from normolipidaemic and dyslipidaemic type 2 diabetic women and controls were isolated and quantified with HPLC and mass spectrometry. A detailed molecular characterisation of VLDL triacylglycerols (TAG) was also performed using the novel ozone-induced dissociation method, which allowed us to distinguish vaccenic acid (C18:1 n-7) from oleic acid (C18:1 n-9) in specific TAG species. Lipid class composition was very similar in VLDL and LDL from normolipidaemic type 2 diabetic and control participants. By contrast, dyslipidaemia was associated with significant changes in both lipid classes (e.g. increased diacylglycerols) and lipid species (e.g. increased C16:1 and C20:3 in phosphatidylcholine and cholesteryl ester and increased C16:0 [palmitic acid] and vaccenic acid in TAG). Levels of palmitic acid in VLDL and LDL TAG correlated with insulin resistance, and VLDL TAG enriched in palmitic acid promoted increased secretion of proinflammatory mediators from human smooth muscle cells. We showed that dyslipidaemia is associated with major changes in both lipid class and lipid species composition in VLDL and LDL from women with type 2 diabetes. In addition, we identified specific molecular lipid species that both correlate with clinical variables and are proinflammatory. Our study thus shows the potential of advanced lipidomic methods to further understand the pathophysiology of type 2 diabetes.
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Social media tools are starting to become mainstream and those working in the software development industry are often ahead of the game in terms of using current technological innovations to improve their work. With the advent of outsourcing and distributed teams the software industry is ideally placed to take advantage of social media technologies, tools and environments. This paper looks at how social media is being used by early adopters within the software development industry. Current tools and trends in social media tool use are described and critiqued: what works and what doesn't. We use industrial case studies from platform development, commercial application development and government contexts which provide a clear picture of the emergent state of the art. These real world experiences are then used to show how working collaboratively in geographically dispersed teams, enabled by social media, can enhance and improve the development experience.
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The structures of the ammonium salts of 3,5-dinitrobenzoic acid, NH4+ C7H3N2O6- (I), 4-nitrobenzoic acid, NH4+ C7H4N2O4- . 2H2O (II) and 2,4-dichlorobenzoic acid, NH4+ C7H3Cl2O2- . 0.5H2O (III), have been determined and their hydrogen-bonded structures are described. All salts form hydrogen-bonded polymeric structures, three-dimensional in (I) and two-dimensional in (II) and (III). With (I), a primary cation-anion cyclic association is formed [graph set R3/4(10)] through N-H...O hydrogen bonds, involving a carboxyl O,O' group on one side and a single carboxyl O-atom on the other. Structure extension involves both N-H...O hydrogen bonds to both carboxyl and nitro O-atom acceptors. With structure (II), the primary inter-species interactions and structure extension into layers lying parallel to (0 0 1) are through conjoined cyclic hydrogen-bonding motifs: R3/4(10) [one cation, a carboxyl (O,O') group and two water molecules] and centrosymmetric R2/4(8) [two cations and two water molecules]. The structure of (III) also has conjoined R3/4(10) and centrosymmetric R2/4(8) motifs in the layered structure but these differ in that he first involves one cation, a carboxyl (O,O') as well as a carboxyl (O) group and one water molecule, the second, two cations and two carboxyl O-groups. The layers lie parallel to (1 0 0). The structures of the salt hydrates (II) and (III) reported in this work, giving two-dimensional layered arrays through conjoined hydrogen-bonded nets provide further illustrations of a previously indicated trend among ammonium salts of carboxylic acids, but the anhydrous three-dimensional structure of (I) is inconsistent.
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This paper describes a novel system for automatic classification of images obtained from Anti-Nuclear Antibody (ANA) pathology tests on Human Epithelial type 2 (HEp-2) cells using the Indirect Immunofluorescence (IIF) protocol. The IIF protocol on HEp-2 cells has been the hallmark method to identify the presence of ANAs, due to its high sensitivity and the large range of antigens that can be detected. However, it suffers from numerous shortcomings, such as being subjective as well as time and labour intensive. Computer Aided Diagnostic (CAD) systems have been developed to address these problems, which automatically classify a HEp-2 cell image into one of its known patterns (eg. speckled, homogeneous). Most of the existing CAD systems use handpicked features to represent a HEp-2 cell image, which may only work in limited scenarios. We propose a novel automatic cell image classification method termed Cell Pyramid Matching (CPM), which is comprised of regional histograms of visual words coupled with the Multiple Kernel Learning framework. We present a study of several variations of generating histograms and show the efficacy of the system on two publicly available datasets: the ICPR HEp-2 cell classification contest dataset and the SNPHEp-2 dataset.
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The ion PhCO2--CHPh, upon collision activation, undergoes competitive losses of CO and CO2 of which the former process produces the base peak of the spectrum. Product ion and substituent effect (Hammett) studies indicate that PhCO2--CHPh cyclises to a deprotonated hydroxydiphenyloxirane which ring opens to PhCOCH(O-)Ph. This anion then undergoes an anionic 1,2-Wittig type rearrangement {through [PhCO- (PhCHO)]} to form Ph2CHO- and CO. The mechanism of the 1,2-rearrangement has been probed by an ab initio study [at MP4(SDTQ)/6-31++G(d,p) level] of the model system HCOCH2O- →; MeO- + CO The analogous system RCO2--CHPh (R = alkyl) similarly loses CO, and the migratory aptitudes of the alkyl R groups in this reaction are Bu′ > Me > Et ∼Pri). This trend correlates with the order of anion basicities (i.e. the order of ΔG○acid values of RH), supporting the operation of an anion migration process. The loss of CO2 from PhCO2--CHPh yields Ph2CH- as the anionic product: several mechanistic scenarios are possible, one of which involves an initial ipso nucleophilic substitution.