Efeito da localização do nó de sutura na recuperação morfofuncional do tendão flexor digital profundo do membro torácico do cão após tenorrafia experimental

Este estudo teve por escopo comparar a influência do nó de sutura em três diferentes localizações na recuperação morfofuncional do tendão flexor digital profundo (TFDP) do cão. Foram utilizados 20 cães divididos em três grupos de oito, sete e cinco animais. Os TFDP do segundo e quinto dedos do membro torácico esquerdo foram seccionados e suturados pela técnica de Kessler modificada, alterando-se a localização do nó e o tipo de sutura no epitendíneo. No grupo um, o nó da sutura ficou localizado na região ventral do tendão e no grupo dois na face dorsal. em ambos os grupos, o epitendão foi suturado com pontos simples separados. No grupo três, o nó da sutura ficou interno ao endotendíneo e o epitendíneo foi suturado com ponto simples contínuo. Após a cirurgia, foi realizada diariamente a movimentação passiva controlada do membro do primeiro ao 15º dia. No 7º e no 15º dia os animais foram sacrificados por anestesia profunda e os tendões foram colhidos para avaliação macroscópica do processo de reparo tendíneo. O critério de comparação utilizou como parâmetros para avaliar a recuperação morfofuncional a ruptura do tendão, o afastamento dos cotos e a coaptação completa dos cotos tendíneos. O grupo que apresentou melhor resultado com relação aos parâmetros avaliados foi o terceiro, com ausência de ruptura e índice de afastamento de apenas 2,5% dos cotos tendíneos. Os resultados encontrados permitem concluir que a localização do nó de sutura na tenorrafia do TFDP interfere na resposta reparadora e biomecânica.

Modeling and Experimental Aspects of Self-healing Bolted Joint through Shape Memory Alloy Actuators

Bolted joints are a form of mechanical coupling largely used in machinery due to their reliability and low cost. Failure of bolted joints can lead to catastrophic events, such as leaking, train derailments, aircraft crashes, etc. Most of these failures occur due to the reduction of the pre-load, induced by mechanical vibration or human errors in the assembly or maintenance process. This article investigates the application of shape memory alloy (SMA) washers as an actuator to increase the pre-load on loosened bolted joints. The application of SMA washer follows a structural health monitoring procedure to identify a damage (reduction in pre-load) occurrence. In this article, a thermo-mechanical model is presented to predict the final pre-load achieved using this kind of actuator, based on the heat input and SMA washer dimension. This model extends and improves on the previous model of Ghorashi and Inman [2004, "Shape Memory Alloy in Tension and Compression and its Application as Clamping Force Actuator in a Bolted Joint: Part 2 - Modeling," J. Intell. Mater. Syst. Struct., 15:589-600], by eliminating the pre-load term related to nut turning making the system more practical. This complete model is a powerful but complex tool to be used by designers. A novel modeling approach for self-healing bolted joints based on curve fitting of experimental data is presented. The article concludes with an experimental application that leads to a change in joint assembly to increase the system reliability, by removing the ceramic washer component. Further research topics are also suggested.

Healing process in anastomosis of homologous venous grafts preserved in glutaraldehyde implanted aorta of rabbits

Aim. Autologous vein (AV) is sometimes not suitable or present for a vascular restoration. Homologous vein preserved in glutaraldehyde may be an alternative to AV, but little is yet known about this graft and its healing process after implantation in arteries. The purpose of this study was to compare the initial healing process of glutaraldehyde-tanned homologous venous grafts (group 1) with fresh autologous venous grafts (group 2), at 4 or 15 days.Methods. Forty Norfolk rabbits were allocated in 2 groups of 20 animals each. The grafts was interposed in the infra-renal aorta of the rabbit. Anastomotic tensile strength (TS), hydroxyproline (HP) determination, and histology (HA) were performed.Results. TS increased in both groups, from the 4th to 15th day, (p < 0.01) in both proximal (G1: from 364.5 &PLUSMN; 98.3 g to 491.8 &PLUSMN; 107.3 g; G2: from 366.26 &PLUSMN; 85.15 g to 518.46 &PLUSMN; 82.79 g) and distal anastomosis (GI: from 363.53 &PLUSMN; 96.26 g to 507.32 &PLUSMN; 91.01 g; G2: from 352.30 &PLUSMN; 102.41 g to 528.67 &PLUSMN; 48.58 g), with no difference between the groups. HP did not change (p > 0.10) in this same period and was similar in both groups, in the proximal (GI: from 677.99 +/- 153.98 mug/100 mg to 914.92 +/- 459.83 mug/100 mg; G2: from 668.65 +/- 170.28 mug/100 mg to 669.46 +/- 319.80 mug/100 mg) as well as in the distal anastomosis (G1:from 740.07 +/- 213.53 mug/100 mg to 923.52 +/- 270.57 mug/100 mg; G2: from 737.66 +/- 266.76 mug/100 mg to 707.68 +/- 171.25 mug/100 mg). Initial inflammatory and reparative features of the anastomosis were similar in both groups.Conclusion. We can conclude that the healing process of the glutaraldehyde-tanned homologous vein graft was similar to that of the fresh autologous venous graft.

Intestinal healing in rats submitted to ethanol ingestion

OBJETIVO: Estudar o efeito do alcoolismo no processo de cicatrização intestinal e suas complicações pós-operatórias em ratos. MÉTODOS: Cento e sessenta ratos foram divididos em dois grupos: tratado e controle. O controle recebeu água, enquanto o tratado etanol a 30%. Após 180 dias foram realizadas colotomia, seguida de anastomose. Após os animais foram divididos em quatro subgrupos de 20 ratos para estudo nos seguintes momentos: 4º, 7º, 14º e 21º pós-operatório. Os parâmetros analisados foram: ganho de peso, força de ruptura, hidroxiprolina tecidual, complicações pós-operatórias e estudo histopatológico. RESULTADOS: O ganho de peso foi superior no grupo controle (p<0,05). Após agrupamento dos momentos a força de ruptura foi superior no controle (p<0,05). Não houve diferença quanto à histopatologia e hidroxiprolina. Houve cinco infecções de incisão no grupo tratado, enquanto no controle ocorreram duas (p>0,05). Houve nove fístulas no grupo tratado, enquanto no controle duas (p<0,05). Ocorreram sete mortes no grupo tratado e apenas três no controle (p>0,05). CONCLUSÕES: No grupo tratado ocorreu um processo de subnutrição evidenciado pelo menor ganho de peso. Piora na cicatrização intestinal, indicada pela menor força de ruptura. Ocorreu um maior número de complicações pós-operatórias no grupo tratado.

Anastomotic healing in ileum and colon of alloxan-induced diabetic rats

OBJETIVO: Investigar se o diabetes mellitus pode alterar a força de ruptura (FR) e o conteúdo de colágeno em anastomoses realizadas no íleo e cólon de ratos. MÉTODOS: 300 ratos Wistar foram distribuídos por sorteio em 5 grupos experimentais com 60 animais cada: controle normal manipulado cirurgicamente (G1); normais controles submetidos a anastomoses no íleo (G2) e cólon (G3); ratos diabéticos submetidos a anastomoses no íleo (G4) e cólon (G5). Cada grupo foi dividido em 6 subgrupos com 10 ratos cada para sacrifícios com 0, 4, 7, 14, 21 e 30 dias após as operações. Os procedimentos cirúrgicos foram realizados 3 meses após a indução do diabetes com aloxana. A FR foi medida em todas anastomoses intestinais. Fragmentos de anastomoses do íleo e cólon foram retirados para dosagens de hidroxiprolina (HP) e proteína tecidual total (PT). RESULTADOS: A FR teve significante redução (P<0,05) nos grupos diabéticos G4 e G5, até 7 e 14 dias após a operação, respectivamente, quando comparada à observada nos grupos controles G2 e G3. Não foram observadas diferenças significantes nas dosagens de HP e PT em ratos diabéticos e controles, tanto operados no íleo como no cólon, em todos os momentos de avaliação. CONCLUSÃO: O diabetes conduz a alterações da força de ruptura de anastomoses intestinais durante a fase inicial da reparação da ferida cirúrgica, porém, este fato parece não estar relacionado à capacidade de sintetizar colágeno.

Efeito tardio e imediato da sutura em tendão extrassinovial íntegro: estudo biomecânico em ratos

OBJETIVO: O objetivo do estudo foi avaliar o efeito, nas propriedades mecânicas, do arranjo de reparo com material de sutura, no tendão calcâneo de rato, na ausência de processo de cicatrização. MÉTODO: Foram utilizados 12 ratos machos da linhagem Wistar. Os animais foram submetidos à colocação de ponto de sutura tipo Kessler modificado no tendão calcâneo. Os sacrifícios foram realizados nos períodos imediato e com seis semanas de pós-operatório. As propriedades mecânicas estudadas foram: carga máxima, tensão na carga máxima e módulo de elasticidade. O tendão contralateral foi usado como controle. RESULTADOS: A análise estatística indicou que, em relação aos períodos estudados, os valores das propriedades mecânicas não apresentaram diferenças significativas. em relação ao controle, isto é, tendão contralateral sem sutura, os resultados demonstram que, com seis semanas de pós-operatório, houve queda dos valores do módulo de elasticidade, enquanto a carga máxima e a tensão na carga máxima não apresentaram variações significativas. CONCLUSÃO: A colocação de material de sutura em tendão extrassinovial não lesado provocou queda do módulo de elasticidade, porém não interferiu na carga máxima e na tensão na carga máxima após seis semanas de pós-operatório.

Constituents and antiulcer effect of Alchornea glandulosa: Activation of cell proliferation in gastric mucosa during the healing process

Alchornea glandulosa (Euphorbiaceae) is a plant used in folk medicine as an antiulcer agent. Rats pretreated with methanolic extract obtained from the leaves of A. glandulosa (AG) showed a dose-dependent effect and significant reduction of gastric ulcers induced by absolute ethanol at the doses of 500 (57%) and 1000 mg/kg (35%) in relation to the control group. Pretreatment of mice with AG (500, 1000 mg/kg, p.o.) showed dose-dependent activity and significantly decreased the severity of lesions caused by HCl/ethanol and by non steroidal anti inflammatory drug-induced gastric lesions. Pretreatment with AG also induced antisecretory action via local and systemic routes and a significant decrease in the total gastric acid content. The gastroprotective effects of AG involved the participation of nitric oxide and increased levels of endogenous sulfhydryl compounds, which are defensive mechanisms of the gastrointestinal mucosa against aggressive factors. The ability of AG to heal gastric ulcers was evaluated after 14 consecutive days of treatment. The results showed that single oral administrations of AG (250 mg/kg/once daily) potently stimulates gastric epithelial cell proliferation that contributes to the accelerated healing of gastric ulcers induced by acetic acid. In addition, no subacute toxicity (body weight gain, vital organs, and serum biochemical parameters) was observed during treatment with AG. Phytochemical investigation of AG led to the isolation of myricetin-3-O-alpha-L-rhamnopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, quercetin-3-O-beta-D-galactopyranoside, quercetin, amentoflavone, methyl gallate, gallic acid, and pterogynidine. We also established the phytochemical profile of AG with the quantification of total phenolic compounds. These compounds may contribute to the observed antiulcerogenic effects of AG.

Use of Adipose Tissue-Derived Mesenchymal Stem Cells for Experimental Tendinitis Therapy in Equines

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

Influence of the ratio of particulate autogenous bone graft/platelet-rich plasma on bone healing in critical-size defects: a histologic and histometric study in rat calvaria

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

Bone healing in critical-size defects treated with platelet-rich plasma activated by two different methods. A histologic and histometric study in rat calvaria

The purpose of this study was to analyze histologically the influence of platelet-rich plasma (PRP) coagulated with two different activators on bone healing in surgically created critical-size defects (CSD) in rat calvaria.Forty-eight rats were divided into three groups: C, PRP-C and PRP-T. An 8 mm diameter CSD was created in the calvarium of each animal. In group C, the defect was filled by a blood clot only. In groups PRP-C and PRP-T, the defect was filled with PRP activated with either calcium chloride or thromboplastin solution, respectively. Each group was divided into two subgroups (n = 8 per subgroup) and killed at either 4 or 12 weeks postoperatively. Histologic and histometric analyses were performed. The amount of new bone formed was calculated as a percentage of the total area of the original defect. Percentage data were transformed into arccosine for statistical analysis (analysis of variance, Tukey's post hoc test, p < 0.05).No defect completely regenerated with bone. Group PRP-C had a statistically greater amount of bone formation than groups C and PRP-T at both time points of analysis. No statistically significant differences were observed between groups C and PRP-T.It can be concluded that the type of activator used to initiate PRP clot formation influences its biological effect on bone healing in CSD in rat calvaria.

Effect of amniotic membrane transplantation on corneal healing and proteoglycan expression in an experimental model of limbal deficiency in rabbits

PURPOSE. Amniotic membrane transplantation (AMT) has been used as a graft or as a dressing in ocular surface reconstruction, facilitating epithelization, maintaining normal epithelial phenotype, and reducing inflammation, vascularization, and scarring. The corneal transparency is due, at least in part, to the arrangement in orthogonal lamellae of collagen fibrils, surrounded by proteoglycans (PGs). These PGs regulate fibrilogenesis, the matrix assembly, and ultimately the corneal transparency. The purpose of the present study was to investigate the effects of AMT upon the corneal PGs after severe limbal injury.METHODS. Experiments were performed on the right corneas of 22 New Zealand female albino rabbits, and their left corneas were used as matched controls. These animals were divided into 3 groups: G1 (n = 10): total peritomy and keratolimbectomy, followed by application of 0.5 M NaOH; G2 (n = 10): submitted to the same trauma as G1, and treated by AMT; G3: no trauma, only AMT (n = 2). The right corneas of G2 and G3 were covered by DMSO 4 cryopreserved human amniotic membrane, fixed by interrupted 9-0 mononylon sutures, with its stromal face toward the ocular surface. After 7 or 30 days, the corneas were removed and PGs were extracted.RESULTS. Normal corneas contained approximately 9 mg of PGs per gram of dry tissue. AMT on intact cornea (G3) did not cause any changes in the concentration of PGs. In contrast, injured corneas contained much less PGs, both on the seventh and on the 30th day posttrauma. The PG concentration was even lower in injured corneas treated by AMT. This decrease was due almost exclusively to dermatan sulfate PGs, and the structure of dermatan sulfate was also modified, indicating changes in the biosynthesis patterns.CONCLUSIONS. Although beneficial effects have been observed on clinical observation and concentration of soluble proteins after AMT, the normal PG composition of cornea was not attained, even 30 days postinjury, indicating that the normal ocular surface reconstruction, if possible, is a long-term process. (Eur J Ophthalmol 2010; 20: 290-9)

Alveolar bone healing process in spontaneously hypertensive rats (SHR). A radiographic densitometry study

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

Raloxifene therapy inhibits osteoclastogenesis during the alveolar healing process in rats

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

Early healing after elevation of the maxillary sinus floor applying a lateral access: a histological study in monkeys

AimTo describe the early healing within the void obtained after the elevation of the sinus mucosa and simultaneous implant installation without the use of any grafting material in monkeys.Material and methodsImplants were installed simultaneously with the elevation of the maxillary sinus using the lateral approach in eight monkeys without the use of grafting material. The healing after 4, 10, 20 and 30 days was evaluated in the area distal to the implants. Paraffin sections were prepared and analyzed using qualitative histological methods.ResultsThe healing process was initiated by the formation of a coagulum and followed by a provisional matrix and woven bone. Subsequently, a parallel-fiber bone replaced woven bone. The dimension of the elevated area shrank during the healing process. Sprouts of woven bone, present to a moderate extent after 4 days, were more numerous after 10 and 20 days. Newly formed bone originated from the sinus walls and septa, while there was no evidence of participation of the Schneiderian membrane in this process. After 30 days, the window access appeared to be closed by a layer of newly formed trabecular bone.ConclusionsThe coagulum that filled the void distal to the implant after simultaneous elevation of the sinus floor gave rise to newly formed bone. However, the void occupied by the coagulum shrank substantially. The Schneiderian membrane did not provide a basis for new bone formation in the early phase of healing.To cite this article:Scala A, Botticelli D, Rangel IG Jr, de Oliveira JA, Okamoto R, Lang NP. Early healing after elevation of the maxillary sinus floor applying a lateral access: a histological study in monkeys.Clin. Oral Impl. Res. 21, 2010; 1320-1326.doi: 10.1111/j.1600-0501.2009.01964.x.