880 resultados para Collagen fibres


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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.

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

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The aim of this study was to evaluate the effects of a Gallium Arsenide (GaAs) laser, using a high final energy of 4.8J, during muscle regeneration after cryoinjury. Thirty Wistar rats were divided into three groups: Control (C, n=10); Injured (I, n=10) and Injured and laser treated (Injured/LLLT, n=10). The cryoinjury was induced in the central region of the tibialis anterior muscle (TA). The applications of the laser (904nm, 50mW average power) were initiated 24h after injury, at energy density of 69Jcm(-1) for 48s, for 5days, to two points of the lesion. Twenty-four hours after the final application, the TA muscle was removed and frozen in liquid nitrogen to assess the general muscle morphology and the gene expression of TNF-, TGF-, MyoD, and Myogenin. The Injured/LLLT group presented a higher number of regenerating fibers and fewer degenerating fibers (P<0.05) without changes in the collagen remodeling. In addition, the Injured/LLLT group presented a significant decrease in the expression of TNF- and myogenin compared to the injured group (P<0.05). The results suggest that the GaAs laser, using a high final energy after cryoinjury, promotes muscle recovery without changing the collagen remodeling in the muscle extracellular matrix.

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

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A general analysis of the behaviour of "Cebus" shows that when this primate moves position to feed or perform another activity, it presents different ways of locomotion. This information shows that the brachial biceps muscle of this animal is frequently used in their locomotion activities, but it should also be remembered that this muscle is also used for other development activities like hiding, searching for objects, searching out in the woods, and digging in the soil. Considering the above, it was decided to research the histoenzimologic characteristics of the brachial biceps muscle to observe whether it is better adpted to postural or phasic function. To that end, samples were taken from the superficial and deep regions, the inserts proximal (medial and lateral) and distal brachial biceps six capuchin monkeys male and adult, which were subjected to the reactions of m-ATPase, NADH-Tr. Based on the results of these reactions fibres were classified as in Fast Twitch Glycolitic (FG), Fast Twitch Oxidative Glycolitic (FOG) and Slow Twitc (SO). In general, the results, considering the muscle as a whole, show a trend of frequency FOG>FG>SO. The data on the frequency were studied on three superficial regions FOG=FG>SO; the deep regions of the inserts proximal FOG=FG=SO and inserting the distal FOG>FG=SO. In conclusion, the biceps brachii of the capuchin monkey is well adapted for both postural and phasic activities.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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The use of bowel segments to perform bladder augmentation is associated with several metabolic and surgical complications. A great variety of synthetic materials, biodegradable or not, have been tested. Collagen-based biomaterials have shown effectiveness for the regeneration and obtainment of a functional bladder. Assess the functional and histological response of the rabbit bladder to anionic collagen membrane (ACM), either when it is anastomosed to the bladder or it is placed onto bladder after vesicomyectomy. In 15 male rabbit a partial cystectomy was performed. After 4 weeks they were divided in 3 groups. Group 1 (G1) - bladder augmentation with ACM. Group 2 (G2) ACM is placed onto bladder after vesicomyectomy. Group 3 (G3) control group. Maximal bladder capacity (MBC) and weight were assessed with 4 (M1), 8 (M2) and 12 (M3) weeks after partial cystectomy. In M3 was performed the sacrifice and extraction of the bladder and kidneys for anatomopathologic study. There were neither bladder stones, nor implant extrusion in M3. There was a significant increase in MBC in G1 and G2 (p<0.05), but no statistical differences in G3 (p=0.35). There is no significant difference comparing G1 and G2. In M3, both groups have shown a bigger MBC than G3 (p<0.05). The microscopic assessment showed an inflammatory reaction in the bladder augmented, with urothelium preserved. The ACM was effective for the increase of MBC. The bladders with preservation of the urothelium have shown an extensive inflammatory process.

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The surface free energy of conditioned-dentin is one of the factors that interfere with monomeric infiltration of the interfibrillar spaces. Saturation of the tooth matrix with different substances may modulate this energy and, consequently, the wettability of the dentin. To evaluate the influence of different substances used to saturate conditioned-dentin on surface free energy (SFE) of this substrate. Dentin blocks (4 × 7 × 1 mm, n = 6/ group), obtained from the roots of bovine incisors, were etched using phosphoric acid for 15 seconds, rinsed and gently dried. The surfaces were treated for 60 seconds with: ultra-purified water (H20-control); ethanol (EtOH), acetone (ACT), chlorhexidine (CHX), ethylenediaminetetraacetic acid (EDTA); or sodium hypochlorite (NaOCl). The tooth surfaces were once again dried with absorbent paper and prepared for SFE evaluation using three standards: water, formamide and bromonaphthalene. Analysis of variance (ANOVA) and Dunnet's tests (a = 0.05) were applied to the data. Ethylenediaminetetraacetic acid was the only substance that caused a change to the contact angle for the standards water and formamide, while only EtOH influenced the angles formed between formamide and the dentin surface. None of the substances exerted a significant effect for bromonaphtha-lene. In comparison to the control, only EDTA and NaOCl altered both polar components of the SFE. Total SFE was increased by saturation of the collagen matrix by EDTA and reduced when NaOCl was used. Saturation of the collagen matrix by EDTA and EtOH changed the surface free energy of the dentin. In addition, the use of NaOCl negatively interfered with the properties evaluated. The increase of surface free energy and wettability of the dentin surface would allow higher penetration of the the adhesive system, which would be of importance to the clinical success of resin-dentin union.

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Few studies has been done using guided bone regeneration in maxillary sinus defects. AIM: To assess the bone repair process in surgical defects on the alveolar wall of the monkey maxillary sinus, which communicates with the sinus cavity, by using collagen membranes: Gen-derm - Genius Baumer, Pro-tape - Proline and autologous temporal fascia. MATERIALS AND METHODS: In this prospective and experimental study, orosinusal communications were performed in four tufted capuchin monkeys (Cebus apella) and histologic analysis was carried out 180 days after. RESULTS: In the defects without a cover (control), bone proliferation predominated in two animals and fibrous connective tissue predominated in the other two. In defects repaired with a temporal fascia flap, fibrous connective tissue predominated in three animals and bone proliferation predominated in one. In the defects repaired with Gen-derm or Pro-tape collagen membranes there was complete bone proliferation in three animals and fibrous connective tissue in one. CONCLUSIONS: Surgical defect can be repaired with both bone tissue and fibrous connective tissue in all study groups; collagen membranes was more beneficial in the bone repair process than temporal fascia or absence of a barrier.

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Objective To evaluate the action of conjugated equine estrogen, raloxifene and isolated or combined genistein-rich soy extracts on collagen fibers in the bones of oophorectomized rats. Materials and methods Seventy female rats received testosterone propionate (0.1 mu g/g) on the 9th day after birth. At 6 months of age, the rats were administered the vehicle (propylene glycol, 0.5 ml/day), and ten of the rats were randomly chosen to comprise the non-oophorectomized control group (GI). The other 60 rats were ovariectomized and randomized into six groups of ten as follows: GII, vehicle; GIII, conjugated equine estrogen (CEE), 50 mu g/kg/day; GIV, raloxifene (RAL), 0.75 mg/kg/day; GV, genistein-rich soy extract (GSE), 300 mg/kg/day; GVI, CEE + GSE, 50 mu g/kg/day + 300 mg/kg/day; and GVII, CEE + RAL, 50 mu g/kg/day + 0.75 mg/kg/day. Three months after surgery, the drugs were administered for 60 consecutive days. All rats were euthanized, and their left tibiae were removed for histological routine. The histological sections were stained with hematoxylin-eosin, and picrosirius for evaluating bone microarchitecture. Types I and II collagen fibers were analyzed by immunofluorescence. Data analysis was carried out with ANOVA and Tukey's test. Results Collagen reduction was significant in the GIII animals when compared to the other groups (p < 0.05). There was no significant difference in the thickness of collagen fibers among the groups. There was a greater quantity of type III collagen in GVI than in the other groups. Conclusion Our data indicate that conjugated equine estrogen improves bone quality because it increases the quantity of type I collagen while reducing the quantity of thin collagen fibers. In addition, the combination of CEE and raloxifene or genistein-rich soy extract is not as efficient as CEE itself to improve bone quality.

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Prosthetic meshes are commonly used to correct abdominal wall defects. However, the inflammatory reaction induced by these devices in the peritoneum is not completely understood. We hypothesized that nitric oxide (NO), produced by nitric oxide synthase 2 (NOS2) may modulate the response induced by mesh implants in the abdominal wall and, consequently, affect the outcome of the surgical procedure. Polypropylene meshes were implanted in the peritoneal side of the abdominal wall in wild-type and NOS2-deficient (NOS2(-/-)) mice. After 15 days tissues around the mesh implant were collected, and inflammatory markers (the cytokine interleukin 1 beta (IL-1 beta) and NO) and tissue remodeling (collagen and metalloproteinases (MMP) 2 and 9) were analyzed. The lack of NOS2-derived NO induced a higher incidence of visceral adhesions at the mesh implantation site compared with wild-type mice that underwent the same procedure (P < 0.05). Additionally, higher levels of IL-1 beta were present in the mesh-implanted NOS2(-/-) animals compared with control and wild-type mice. Mesh implantation induced collagen I and III deposition, but in smaller amounts in NOS2(-/-) mice. MMP-9 activity after the surgical procedure was similarly increased in both groups. Conversely, MMP-2 activity was unchanged in mesh-implanted wild-type mice, but was significantly increased in NOS2(-/-) mice (P < 0.01), due to decreased S-nitrosylation of the enzyme in these animals. We conclude that NOS2-derived NO is crucial for an adequate response to and integration of polypropylene mesh implants in the peritoneum. NO deficiency results in a prolonged inflammatory reaction to the mesh implant, and reduced collagen deposition may contribute to an increased incidence of visceral adhesions. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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Studies on the collagen system of the human myocardium are still limited compared to those on small laboratory animals. The aim of this work was to observe the collagen tissue of the myocardium of the human heart as a function of age. The types of collagen, as well as the density of collagen tissue and the diameter of collagen fibrils, were examined. Fragments of the left ventricular wall from 15 hearts, 5 from children, 5 from young adults, and 5 from elderly individuals, were analyzed by using the Picrosirius-polarization method and by transmission electron microscopy (TEM). The results showed the presence of collagen type III and collagen type I, both in the endomysium and perimysium of the 3 groups studied. Measurements of collagen content in myocardial tissue displayed that both endomysial and perimysial collagen increase in number and thickness in the adult and elderly. These histochemical results coincided with the observations obtained with the electron microscope in showing an increase in the number of collagen fibrils with a large diameter in the adult and elderly hearts. The present results on cardiac collagen may be important for assessing the pathogenesis of several cardiopathies in the hearts of children, young adults, and the elderly.

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Purpose: To investigate the effects of hypercholesterolemic diet on the collagen composition of urinary bladder wall. Materials and methods: Forty-five female 4-week-old Wistar rats were divided into three groups: 1) control group fed a normal diet (ND); 2) model of bladder outlet obstruction (BOO) group fed a ND; and 3) group fed a HCD (1.25% cholesterol). Total serum cholesterol, LDL cholesterol and body weight were assessed at baseline. Four weeks later, group 2 underwent a surgical procedure resulting in a partial BOO, while groups 1 and 3 underwent a sham similar surgical procedure. Six weeks later, all animals had their bladders removed; serum cholesterol and LDL cholesterol levels and body weights were measured. Morphological and morphometric analysis was performed by Picrosirius staining and collagen types I and III were identified by immunofluorescence. Statistical analysis was completed and significance was considered when p<0.05. Results: Rats fed an HCD exhibited a significant increase in LDL cholesterol levels (p<0.001) and body weight (p=0.017), when compared to the groups fed a ND during the ten-week study period. Moreover, the HCD induced morphological alterations of the bladder wall collagen, regarding thin collagen fibers and the amounts of type III collagen when compared to the control group (p=0.002 and p=0.016, respectively), resembling the process promoted in the BOO model. Conclusions: A hyper-cholesterolemic diet in Wistar rats promoted morphological changes of the bladder types of collagen, as well as increases in body weight and LDL cholesterol.

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This work aimed to study the characteristics of the fibres of the species Bactris setosa ('tucum') used by close-knit social groups, located in Sorocaba - Sao Paulo - Brazil, in basket-making techniques, for possible applications in textile activity. Optical microscopy (NBR 13 538:1995) and Tensile Properties (ASTM D 3 822-2001) were used to assess properties such as the fibre structre, linear density, breaking force, elongation at break and breaking tenacity of each species. Bactris setosa showed a longitudinal view similar to that of sisal; an average linear density of 41.2 tex, a tenacity average of 11.96 cN/tex, closer to fiberglass, and an elongation ranging between 1.35 and 3.87%. It is important to clarify the delicacy and detail of the tests, and from this we highlight the importance of carrying out these studies, based on which science and technology must be linked with socio-environmental aspects.