Effects of glycosaminoglycan polysulphate on the organisation of collagen fibres in experimentally induced tendonitis in horses

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Injectable gels of anionic collagen : rhamsan composites for plastic correction: Preparation, characterization, and rheological properties

The present article describes the preparation and characterization A anionic Collagen gels obtained from porcine intestinal submucosa after 72 h of alkaline treatment and in the form of rhamsan composites to develop injectable biomaterials for plastic for construction. All materials were characterized by SDS/polyacrylamide gel electrophoresis, infrared spectroscopy, thermal stability, potentiometric titration, rheological properties, and fluidity tests. Biocompatibility was appraised after the injection of anionic collagen:rhamsan composites at 2.5% in 60 North Folk rabbits. Independently of processing, the Collagen's secondary structure was preserved in all cases, and after 72 h of hydrolysis the Collagen was characterized by a carboxyl group content of 346 :L 9, which, at physiological pH, corresponds to an increase of 106 17 negative charges, in comparison to native Collagen, due to the selective hydrolysis of asparagine and glutamine carboxyamide side chain. Rheological studies of composites at pH 7.4 in concentrations of 2, 4, and 6% (in proportions of 75:1 and 50:1) showed a viscoelastic behavior dependent on the frequency, which is independent of concentration and proportion. In both, the concentration of the storage modulus always predominated over the loss modulus (G' > G and delta < 45 degrees). The results from creep experiments confirmed this behavior and showed that anionic collagen:rhamsan composites at pH 7.4 in the proportion of 50:1 are less elastic and more susceptible to deformation in comparison to gels in the proportion of 75:1, independent of concentration. This was further confirmed by flow experiments, indicating that the necessary force for the extrusion of anionic collagen:rhamsan composites, in comparison to anionic Collagen, was significantly smaller and with a smooth flow. Biocompatibility studies showed that the tissue reaction of anionic collagen:rhamsan composites at 2.5% in the proportion of 75:1 was compatible with the application of these gels in plastic reconstruction. These results suggest that the association of Collagen with rhamsan may be a good alternative in the replacement of glutaraidehyde to stabilize the microfibril assembly of commercial Collagen gel preparations. (c) 2005 Wiley Periodicals, Inc.

Nitric oxide and brazilian propolis combined accelerates tissue repair by modulating cell migration, cytokine production and collagen deposition in experimental leishmaniasis

The fact that drugs currently used in the treatment of Leishmania are highly toxic and associated with acquired resistance has promoted the search for new therapies for treating American tegumentary leishmaniasis (ATL). In this study, BALB/c mice were injected in the hind paw with Leishmania (Leishmania) amazonensis and subsequently treated with a combination of nitric oxide (NO) donor (cis-[Ru(bpy)(2)imN(NO)](PF6)(3)) (Ru-NO), given by intraperitoneal injection, and oral Brazilian propolis for 30 days. Ru-NO reached the center of the lesion and increased the NO level in the injured hind paw without lesion exacerbation. Histological and immunological parameters of chronic inflammation showed that this combined treatment increased the efficacy of macrophages, determined by the decrease in the number of parasitized cells, leading to reduced expression of proinflammatory and tissue damage markers. In addition, these drugs in combination fostered wound healing, enhanced the number of fibroblasts, pro-healing cytokines and induced collagen synthesis at the lesion site. Overall, our findings suggest that the combination of the NO donor Ru-NO and Brazilian propolis alleviates experimental ATL lesions, highlighting a new therapeutic option that can be considered for further in vivo investigations as a candidate for the treatment of cutaneous leishmaniasis.

Flow-injection spectrophotometric determination of dipyrone in pharmaceutical formulations using ammonium molybdate as chromogenic reagent

A simple and rapid flow-injection spectrophotometric method is reported for the determination of dipyrone in pharmaceutical formulations. The method is based on the reaction of dipyrone with ammonium molybdate in acidic medium to produce blue molybdenum, which was detected spectrophotometrically at 620 nm. The analyte was determined in a single-line flow system. The calibration curve obtained was linear in the range of 5x10(-4) to 8x10(-3) mol L-1 for dipyrone concentration and the precision ( s r =1.7%) was satisfactory. The method proved to be selective and adequately sensitive. Application of the method to the analysis of pharmaceutical samples resulted in excellent accuracy; the percent mean recoveries were in the range 95.3%-101% and relative errors less than 5.0% for five pharmaceutical formulations were found.

Intravitreal injection versus sub-Tenon's infusion of triamcinolone acetonide for refractory diabetic macular edema: A randomized clinical trial

PURPOSE. To compare the effectiveness of posterior sub-Tenon's infusion (STi) and intravitreal injection (IVI) of triamcinolone acetonide (TA) for treatment of refractory diffuse diabetic macular edema.METHODS. Thirty-six phakic diabetic patients with refractory diffuse diabetic macular edema were prospectively enrolled. Patients randomly received either 40 mg STi or 4 mg IVI of TA. Comprehensive ophthalmic evaluation was performed at baseline and 1, 2, 4, 8 +/- 1, 12 +/- 2 and 24 +/- 2 weeks after treatment. Macular morphologic changes detected by optical coherence tomography and visual acuity, intraocular pressure, and lens status were evaluated.RESULTS. Twenty-eight patients (28 eyes) completed the 24-week study. Central macular thickness was significantly reduced in the IVI group when compared with the STi group at 2, 4, 8, 12, and 24 weeks after treatment (P < 0.01). Mean visual acuities (in logarithm of the minimum angle of resolution [logMAR]) at week-4, -8, and -12 follow-up examinations were significantly higher in the IVI group (0.74, 0.75, and 0.82, respectively) when compared with the STi group (0.88, 0.88, and 0.90, respectively; P < 0.01). A significant change from baseline in mean intraocular pressure (mm Hg) was seen at weeks 4 (+/- 3.21) and 8 (+/- 3.35) in STi the group (P < 0.01), and at week 8 (+/- 2.78) in the IVI group (P < 0.05). No patient had cataract progression during the study.CONCLUSIONS. Although the number of patients and length of follow-up in this preliminary study were limited, the changes in central macular thickness and visual acuity observed after treatment suggest that IVI TA may be more effective than STi for the management of refractory diffuse diabetic macular edema. Further studies are needed to confirm these preliminary findings.

Expression of matrix metalloproteinases, type IV collagen, and interleukin-10 in rabbits treated with morphine after lamellar keratectomy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Intralesional polysulphated glycosaminoglycan as treatment of equine collagenase induced tendinitis: clinical, ultrasonographic and histopathologic evaluation

Estudou-se o efeito de aplicações intratendíneas do polissulfato de glicosaminoglicanas (PSGAG) no tratamento de tendinite induzida pela colagenase. Dois grupos (GI e GII) de cinco eqüinos da raça Puro-Sangue Árabe, machos e fêmeas, com idades entre dois e seis anos, foram submetidos à tendinite do tendão flexor digital superficial do membro torácico esquerdo por aplicação intratendínea de 1,0ml de colagenase (2,5mg/ml). Decorridos sete dias da indução da lesão, os eqüinos do GI receberam cinco aplicações intralesionais de 1,0ml (125mg) de PSGAG, a intervalos de quatro dias, enquanto que os do GII receberam aplicações de solução fisiológica em igual volume e freqüência. Efetuaram-se avaliações clínicas e ultra-sonográficas, periodicamente, durante 150 dias. Todos os animais apresentaram claudicação e aumento local de sensibilidade, de temperatura e de volume 24 horas após a indução da lesão. Com exceção do aumento de volume, que permaneceu visível até o final do experimento, observou-se regressão de todos os sinais em todos os animais. A avaliação ultra-sonográfica evidenciou lesões de tamanho, forma e posição variados, de maior severidade entre o sétimo e 23º dia. Ao término do experimento, o grau de ecogenicidade encontrava-se entre 1 e 2, e o grau de paralelismo entre 0 e 2. A análise histopatológica evidenciou áreas cicatriciais com intensa fibroplasia e neovascularização, fibras colágenas pouco organizadas e endotendão hipercelular e espessado. Não se observou diferenças significativas entre os grupos quanto ao processo de reparação das lesões, concluindo-se que a aplicação intralesional de PSGAG não produziu efeito benéfico para tratar tendinite induzida por colagenase.

Incontinência urinária após gonadectomia em fêmeas caninas

A incontinência urinária adquirida é uma condição debilitante e, muitas vezes, incurável que acomete fêmeas castradas e raramente fêmeas inteiras ou machos. A manifestação clínica pode ocorrer em qualquer momento após a gonadectomia e resulta em graves problemas no manejo do paciente. Os mecanismos que desencadeiam a incontinência após ovariectomia envolvem decréscimo na pressão de fechamento uretral, alterações hormonais, aumento na deposição de colágeno na musculatura lisa da bexiga, diminuição na contratilidade do músculo detrusor e redução na resposta aos estímulos elétricos e ao carbachol. O diagnóstico é realizado pelo histórico do animal, pelo exame físico, pelos exames laboratoriais, pelo perfil de pressão uretral, pela ultrassonografia e pelas radiografias abdominais. O tratamento clínico envolve utilização de fármacos -adrenérgicos, estrógenos, análogos de GnRH e agentes antidepressivos. As técnicas cirúrgicas recomendadas correspondem à uretropexia, cistouretropexia, aplicação de colágeno na uretra e colpossuspensão. Melhor compreensão da etiologia, da fisiopatologia, dos métodos de diagnóstico e tratamentos é fundamental em razão do pouco conhecimento e da identificação dessa condição no Brasil.

Intra-prostatic injection of botulinum toxin type A in treatment of dogs with spontaneous benign prostatic hyperplasia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of heat stress or lipopolysaccharide (E-coli) injection on HSP70 levels in the liver and brain of adrenalectomized rats

Hsp70 content (ng Hsp70 mu g total protein(-1)) in the liver and brain of control and adrenalectomized male rats was investigated by Western Blotting after heat stress (40 degrees C) or endotoxin-induced fever (E. coli lipopolysaccharide injection). The increase in rectal temperature was higher after heat stress than after LPS injection, Heat stress affected Hsp70 content of the liver, but not of the brain; however adrenalectomy did not influence any parameter. These results suggest that, under these circumstances, there is no relationship between the hypothalamic-pituitary-adrenal axis and Hsp70 synthesis in liver and brain. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Production of reinforced composites with natural fibers for industrial applications - Extrusion and injection WPC

The aim of this work is to study the replacement of currently used thermoplastics by composites reinforced with vegetable fibers with several advantages, mainly better mechanical properties, low weight and competitive cost compared to its counterparts. Extrusion and injection molding processes were studied using polypropylene (PP) matrix. The raw materials used were sugar cane bagasse, elephant grass, wood, milk cartons and recycled polypropylene. The composites were tested for bending, tension, hardness and impact resistance, following ASTM standards. The results obtained were extremely positive since they proved that natural fibers as reinforcement can be an important alternative to replace talc and other fillers.

State-of-the-art for extrusion and injection moulding FPC: natural Fibre Plastics Composites in Brazil

Environmental and economical concerns are stimulating research of new materials for construction, furniture, packaging and automotive industries. Particularly attractive are the new materials. This paper presents results about the properties of composites of polyhydroxybutyrate (PHB), polypropylene (PP) and High Density Polyethylene (HDPE) reinforced with natural fibres. The composites were prepared through the extrusion with natural fibres, in an ratio of 30% by weight. The quality of samples was tested utilising injection moulded samples, according to ASTM standards. Results showed that natural fibres can act as an excellent reinforcing material, resulting in low cost composites and improving economical and ecological interests.

Electrical properties of polymer/metal interface in polymer light-emitting devices: electron injection barrier suppression

The electrical characterization of a high efficient multilayer polymer light emitting diode using poly[(2-methoxy-5-hexyloxy)-p-phenylenevinylene] as the emissive layer and an anionic fluorinated surfactant as the electron transport layer was performed. For the sake of comparison, a conventional single layer device was fabricated. The density current vs. voltage measurements revealed that the conventional device has a higher threshold voltage and lower current compared to the surfactant modified device. The effective barrier height for electron injection was suppressed. The influence of the interfaces and bulk contributions to the dc and high frequencies conductivities of the devices was also discussed. (c) 2006 Springer Science + Business Media, Inc.

Interaction mechanism of poly (o-ethoxyaniline) and collagen blends

Blend films of poly (o-ethoxyaniline) (POEA) and collagen were fabricated by casting under optimized conditions and characterized by Raman scattering and UV-vis absorption spectroscopies. The UV-vis spectra showed that the addition of collagen in the aqueous solution of POEA promotes a dedoping of the POEA. This effect was also observed for the blend films as supported by Raman scattering and a mechanism for the chemical interaction between POEA-collagen is proposed. The influences of different percentage of collagen as well as the pH of stock solutions during the fabrication process of the blend films were also investigated. It was found that the preparation method plays an important role in the flexibility and freestanding properties of the films. Complementary, the surface morphology was studied by atomic force microscopy and the conductivity by dc measurements. (C) 2003 Elsevier Ltd. All rights reserved.

Effect of ion concentration of ionomer in electron injection layer of polymer light-emitting devices

Polymer light-emitting devices (PLEDs) with poly(2-methoxy-5-hexyloxy)-p-phenylenevinylene (OC1OC6-PPV) as the emissive layer were studied with an electron injection layer of ionomers consisting of copolymers of styrene and methylmethacrylate (PS/PMMA) with 3, 6 and 8 mol% degree of sulfonation. The ionomers were able to form very thin films over the emissive layer, with less than 30 nm. Additionally, the presence of ion pairs of ionomer suppresses the tendency toward dewetting of the thin film of ionomer (similar to 10 nm) which can cause malfunction of the device. The effect of the ionomers was investigated as a function of the ion content. The devices performance, characterized by their current density and luminance intensity versus voltage, showed a remarkable increase with the ionomer layer up to 6 mol% of ionic groups, decreasing after that for the 8 mol% ionomer device. The study of the impedance spectroscopy in the frequency range from 0.1 to 10(6) Hz showed that the injection phenomena dominate over the transport in the electroluminescent polymer bulk. (c) 2006 Elsevier B.V. All rights reserved.