Hemocompatibility of bioprosthetic heart valve materials respectively based on glutaraldehyde and non-glutaraldehyde treatment / 中国胸心血管外科临床杂志

@#Objective    To study the hemocompatibility of bioprosthetic heart valve materials respectively based on glutaraldehyde and non-glutaraldehyde treatment. Methods    Fresh bovine pericardium was treated with glutaraldehyde or non-glutaraldehyde after adipose tissue was removed. To evaluate the hemocompatibility of the two bioprosthetic heart valve materials, hemolysis test, in vitro fibrinogen adsorption experiment, platelet adhesion experiment, thrombin-antithrombin complex (TAT) test, complement activation assay and ex vivo circulation experiment were performed. Results    The hemolysis test results demonstrated that both of the materials showed hemolytic rates lower than 5%. The results of TAT test and complement activation assay showed no statistical differences among the two materials and the blank control group. Compared to the bioprosthetic heart valve materials with glutaraldehyde-based treatment, the materials with non-glutaraldehyde-based treatment showed significantly decreased fibrinogen adsorption, platelet adhesion and thrombosis. Conclusion    Compared to the bioprosthetic heart valve materials with glutaraldehyde-based treatment, the materials with non-glutaraldehyde-based treatment show better hemocompatibility.

Biocompatibility of bioprosthetic heart valve materials with a non-glutaraldehyde-based chemical treatment / 中国胸心血管外科临床杂志

@#Objective    To study the biocompatibility of bioprosthetic heart valve material with a non-glutaraldehyde-based treatment, and to provide the safety data for the clinical application. Methods    All the tests were conducted according to GB/T16886 standards. The in vitro cytotoxicity was determined by methyl thiazolyl tetrazolium assay. Fifteen guinea pigs were divided into a test group (n=10) and a control group (n=5) in the skin sensitization test. Three New Zealand white rabbits were used in the intradermal reactivity test. Five sites on both sides of the rabbit back were set as test sites and control sites, respectively. In the acute systemic toxicity test, a total of 20 ICR mice were randomly assigned to 4 groups: a test group (polar medium), a control group (polar medium), a test group (non-polar medium) and a control group (non-polar medium), 5 in each group. Forty SD rats were divided into a test group (n=20) and a control group (n=20) in the subchronic systemic toxicity test. Results    The viability of the 100% extracts of the bioprosthetic heart valve material with a non-glutaraldehyde-based treatment was 75.2%. The rate of positive reaction was 0.0%. The total intradermal reactivity test score was 0. There was no statistical difference in the body weight between the test group and control group in the acute systemic toxicity test. There was no statistical difference in the body weight, organ weight, organ weight/body weight ratio, blood routine test or blood biochemistry between the test group and control group in the subchronic systemic toxicity test. Conclusion    The bioprosthetic heart valve material with a non-glutaraldehyde-based treatment has satisfying biocompatibility, which conforms to relevant national standards. The material might be a promising material for application in valve replacement.

An alternative to skin graft for superficial surgical defect in oral cancer surgery / Uma alternativa ao enxerto de pele para defeitos cirúrgicos superficiais em cirurgia de câncer oral

Abstract Introduction: After surgery for oral cavity cancer, superficial surgical defects are usually covered with a skin graft that can be harvested with different thicknesses depending on the reconstructive need. Despite its popularity and efficacy, this solution has the disadvantage of excessive harvesting times and scarring of the donor site. Other surgeons have proposed the use of bovine pericardium as a reconstructive solution. Its use in otorhinolaryngology especially after oral cavity surgery has never been reported. Objective: The aim of this manuscript is to present our preliminary experience with the use of a collagen membrane obtained from bovine pericardium in the reconstruction of small and superficial defects after transoral resection of oral cavity tumors. Methods: A bovine collagen membrane was used to cover surgical defects in 19 consecutive patients undergoing transoral resection of small/superficial oral cancers. Photographs were obtained in the postoperative period to follow the healing process. We analyzed the pro and cons of this tool, recorded data on postoperative chewing-, speechand taste-related quality of life, and tested the most appropriate settings providing the best reconstructive result. Results: The bovine collagen membrane allowed us to cover surgical defects of varying size in different oral sites. Shaping and placement proved to be simple. The membrane facilitated physiologic tissue repair: after one month it was completely absorbed and replaced by the patient's own mucosa. No adverse features were observed in the cohort. Conclusion: A bovine collagen membrane can represent a fast and easy solution in cases of split-thickness defect. Unlike a skin graft, it is not associated with donor site morbidity and allows the patient's own mucosa to be restored with a more physiological result.

Resumo Introdução: Os defeitos cirúrgicos superficiais pós-cirurgia para câncer de cavidade oral geralmente são cobertos com um enxerto de pele que pode ser colhido com diferentes espessuras, depende das necessidades de reconstrução. Apesar de sua popularidade e eficácia, essa solução tem a desvantagem dos tempos excessivos de colheita e cicatrização do local doador. Outros cirurgiões propuseram o uso do pericárdio bovino como solução reconstrutiva, enquanto seu uso em otorrinolaringologia, especialmente após cirurgia de cavidade oral, nunca foi relatado. Objetivo: Apresentar nossa experiência preliminar com o uso de uma membrana de colágeno obtida do pericárdio bovino, na reconstrução de defeitos pequenos e superficiais após resseçcão transoral de tumores da cavidade oral. Método: Uma membrana de colágeno bovino foi usada para cobrir defeitos cirúrgicos em 19 pacientes consecutivos submetidos à resseçcão transoral de câncer oral pequeno/superficial. As fotografias foram obtidas no pós-operatório para acompanhar o processo de cicatrização. Analisamos os prós e contras desse enxerto, registramos dados sobre a qualidade de vida relacionada à mastigação, fala e paladar no pós-operatório e testamos as configurações mais apropriadas, para proporcionar o melhor resultado reconstrutor. Resultados: A membrana de colágeno bovino nos permitiu cobrir defeitos cirúrgicos de tamanhos variados nos diferentes sítios orais. A modelagem e a colocação demonstraram ser simples. A membrana guiou o reparo fisiológico do tecido e após um mês foi completamente absorvida e substituída pela mucosa do próprio paciente. Não foram observadas características adversas na coorte. Conclusão: Uma membrana de colágeno bovino pode representar uma solução rápida e fácil em casos de defeitos de espessura dividida. Ao contrário de um enxerto de pele, ele não está associado à morbidade do local doador e permite que a mucosa do próprio paciente seja restaurada com um resultado mais fisiológico.

Comparative analysis of tissular response after abdominal wall repair using polypropylene mesh and bovine pericardium mesh / Análise comparativa da resposta tecidual após reparo da parede abdominal utilizando tela de polipropileno e de pericárdio bovino

ABSTRACT Background: The use of polypropylene meshes for surgical repair of the abdominal wall contributes to a reduction of the of recurrence rates of hernias or defects. However, its intra-abdominal use comes along with the formation of adhesions and several complications. The study and the search for alternative materials, including bovine pericardium, have been regarded as an option for the correction and treatment of resulting hernias with better adaptations and effectiveness. Aim: Evaluating the inflammatory process of the bovine pericardium in comparison with the inflammatory process of synthetic polypropylene mesh. Method: Bovine pericardium mesh and polypropylene mesh were placed, both on the same animal. The first group had the mesh removed for analysis on day 20, and the second group on day 40. The variables congestion, granulation, giant cells, necrosis, acute inflammation, chronic inflammation and collagen were analyzed. Results: All variables were found in greater numbers as a response to the polypropylene mesh, except for the collagen, which, on day 40, was greater in response to the bovine pericardium mesh. Conclusion: The data in this study suggest that there is less inflammatory reaction in response to bovine pericardium mesh when compared to polypropylene mesh.

RESUMO Racional: O uso de telas de polipropileno para a correção cirúrgica da parede abdominal contribui para redução dos índices de recidiva das hérnias ou defeitos. No entanto, o seu uso intra-abdominal cursa com a formação de aderências e diversas complicações. O estudo e a busca por materiais alternativos, como pericárdio bovino, têm se mostrado uma opção na correção e tratamento de hérnias que resultem com melhores adaptações e efetividades. Objetivo: Avaliar o processo inflamatório do pericárdio bovino em comparação ao processo inflamatório da tela sintética de polipropileno. Método: Foi realizada a colocação de tela de pericárdio bovino e polipropileno, ambas no mesmo animal. O primeiro grupo as teve retiradas para análise no dia 20, e o segundo grupo no dia 40. Foram analisadas as variáveis congestão, granulação, células gigantes, necrose, inflamação aguda, inflamação crônica e colágeno. Resultados: Todas as variáveis foram encontradas em maior número como resposta a tela de polipropileno, exceto a variável colágeno, que no dia 40 apresentou-se em maior quantidade em resposta à tela de pericárdio bovino. Conclusão: Há menor reação inflamatória em resposta a tela de pericárdio bovino, quando comparada com a de polipropileno.

Endothelialization of acellular scaffold from sterilized bovine pericardium / 中国组织工程研究

BACKGROUND: In the research of tissue engineering, there are inevitably various kinds of microorganisms attached to animal tissues, and asepsis is a basic requirement of clinical application of tissue engineering materials. OBJECTIVE: To investigate the effect of 75% ethanol sterilization on the properties and biocompatibility of bovine pericardium. METHODS: Bovine pericardial tissue was sterilized with sterile PBS (control group), PBS containing 1% antibiotic (penicillin/streptomycin/ amphotericin B solution), chlorhexidine and 75% ethanol. LB solid medium was used to evaluate the bactericidal effect of four methods. VB staining was used to evaluate the effect of four sterilization treatments on the tissue structure of bovine pericardium. The cytotoxicity of four sterilized extracts was determined by the CCK-8 assay. The bovine pericardium was sterilized with 75% ethanol and then used to make acellular scaffold, which was co-cultured with human umbilical vein endothelial cells to observe the effect of cell adhesion and endothelialization. RESULTS AND CONCLUSION: (1) The bovine pericardium treated with 75% ethanol and chlorhexidine for 24 hours met the requirements of complete sterilization, and significant colony formation was observed in 1% antibiotic-treated and control groups. (2) VB staining revealed that the collagen fibers of bovine pericardium treated with 75% ethanol, chlorhexidine and 1% antibiotic were arranged in wavy pattern, with compact structure, less elastic fiber content but clear structure.(3) Bovine pericardium treated with 75% ethanol did not affect the proliferation activity of L929 cells, and the cell survival rate within 1-3 days was more than 100%. Chlorhexidine-sterilized bovine pericardium had strong cytotoxicity, leading to cell death. (4) Human umbilical vein endothelial cells grew and adhered normally on the surface of acellular scaffold. During the 20-day implantation period, the highest number of cells adhering to acellular scaffold appeared on days 8-12. These results suggest that 75% ethanol could effectively eliminate all microorganisms attached to the bovine pericardium without affecting the histological integrity and biocompatibility.

Effects from Fiber Orientations of Bovine Pericardium on its Compression Performance / 医用生物力学

Objective To investigate the mechanical behavior of bovine pericardium with different orientations after compression and evaluate its effects on the duration of transcatheter aortic valve. Methods According to the fiber directions, the pericardial strips were divided into 12 groups of transverse, longitudinal and oblique pericardial strips, and each group included 3 strips of pericardium. One strip maintained the original state, and the other two strips were under 12.5 N and 25 N compression, respectively for 1 h. The mechanical properties of compressed samples were tested and analyzed subsequently in uniaxial tension test. Results The samples with different orientations showed obvious anisotropy before and after compression. The secant modulus, elastic modulus and ultimate tensile strength of the longitudinal pericardium were generally greater than those of the oblique pericardium, while the oblique pericardium was larger than the transverse pericardium. For longitudinal and oblique bovine pericardium under 25 N compression, the average tensile strength ratio was 0.92 and 0.87, respectively, and the ratio of tensile strength before and after compression had a significant difference (P＜0.05). The average tensile strength ratio of transverse bovine pericardium after 25 N compression was 0.97, and there was no significant difference in the ratio of tensile strength before and after compression (P＞0.05). Conclusions The compressive damage of the pericardia with different fiber orientations was very small under low stresses at transitory time. For design and production of transcatheter aortic valves, the orientations of the pericardium and the changes of strength after compression should be taken into consideration.

Evaluation of bovine pericardium performance after liquid nitrogen freezing and thinning / 生物医学工程学杂志

In the present study, the performance of the liquid nitrogen frozen and thinned bovine pericardium was studied and compared with the porcine pericardium. The microstructure and mechanical properties of the bovine pericardium were observed and tested by hematoxylin-eosin (HE) staining and tensile test respectively. In all conditions, porcine pericardium was selected as a control group. The results showed that there was little difference in the performance of bovine pericardium after being frozen by liquid nitrogen. The secant modulus and ultimate strength of the thinned bovine pericardium were similar to those of porcine pericardium, however, the elastic modulus was a little higher than porcine pericardium. The study suggested that the performance of the thinned bovine pericardium was similar to those of porcine pericardium. It was easy for the thinned bovine pericardium to obtain a relatively ideal thickness and expected performance, therefore, the thinned bovine pericardium can be used as the materials of transcatheter aortic valve leaflets.

Safety and effectiveness of domestic bovine pericardium as ovine pulmonary artery and descending aorta patch / 复旦学报（医学版）

Objective To evaluate the safety and effectiveness of a newly domestic bovine pericardium using a juvenile sheep model and to provide proof for clinical use.Methods Under the off-pump condition,8 domestic bovine pericardiums were implanted into the pulmonary artery and the descending aorta of 4 juvenile sheep as the trial group.As the control group,four imported bovine pericardiums were implanted into two juvenile sheep.Before the surgery,the juvenile sheep were given a physical examination and some laboratory tests.Ultrasonic cardiographs were taken after 1 month and 2 months of implantation.Sheep were sacrificed after 90 days and compared with the extent of endothelialization,inflammation and calcification of the two groups.Results (1) All the juvenile sheep survived without any complications.(2) Ultrasonic cardiograph showed the absence of leakage,thrombus,calcification,neoplasm or any structural deterioration.(3) Gross examination showed there was no intimal hyperplasia.The thickness and tenacity of all patches had no change compared with the pre-operation condition.All the patches showed smooth and pliable faces without degeneration,as well as absence of macroscopically calcification.(4) There was not any positive result in microbiological tests in both groups.The degree of inflammation,necrosis and calcification had no significant differencs between the two groups.Conclusions The data shows that the domestic bovine pericardium,a newly developed Chinese domestic-design and manufactured bovine pericardium,can exhibit long-term satisfactory safety and efficacy in the implantation of the pulmonary artery and the descending aorta of juvenile sheep.

Aortic Valve Repair of Aortic Valve Insufficiency in the Young Woman after Congenital Heart Disease Operation / 日本心臓血管外科学会雑誌

Interest in aortic valve repair has been growing for more than a decade. Since ross and associates 1) first introduced single cusp enlargement, cusp extension or replacement of aortic valve insufficiency has been used with rheumatic and congenital aortic valve disease. There is more interest on the effectiveness and durability of the leaflet extension technique with autologous pericardium and long-term clinical results. A 29-year-old woman had suffered from aortic valve insufficiency after congenital heart disease operation. Echocardiography and computed tomography showed right cusp shortening with severe aortic valve regurgitation. We perfomed right cusp extension with bovine pericardium and central plication. According to some reports, the stability of autologous pericardium being better than bovine pericardium, but this case could not use a autologous pericardium because of a previous operation. The patient had an uneventful postoperative course and pregnancy became possible.

Bovine pericardium wrapping pancreatic stump for prevention of pancreatic leak after distal pancreatectomy / 中华普通外科杂志

Objective To evaluate the safety and efficacy of bovine pericardium wrapping stump after distal pancreatectomy in a porcine model.Methods Thirty-two swine were randomly assigned to control group (n =16,conventional scalpel transection with hand-sewn closure of the pancreatic remnant)and experiment group (n =16,bovine pericardium wrapping stump combined with hand-sewn).Closedsuction drainage was collected daily until the tenth postoperative day.Animals were killed for necropsy at 3 weeks postoperatively and the pancreatic remnant was sampled for histology.Results The incidence of pancreatic leak in the wrapping group was lower than that in the control group (6.2 vs.46.7％,P ＜0.05).The amount of drainage fluid was higher in the control group during the postoperative period (25.1 ml vs.54.2 ml,P ＜ 0.01).There were no differences in operative time or other clinical parameters measured.No other significant differences were found in macroscopic changes between the two groups.Histology demonstrated focal,chronic inflammation with necrosis at the stump in all animals.Conclusions Bovine pericardium wrapping stump effectively reduced the incidence of pancreatic leakage after distal pancreatectomy.

Freeze-drying microscopy in mathematical modeling of a biomaterial freeze-drying

Transplantation brings hope for many patients. A multidisciplinary approach on this field aims at creating biologically functional tissues to be used as implants and prostheses. The freeze-drying process allows the fundamental properties of these materials to be preserved, making future manipulation and storage easier. Optimizing a freeze-drying cycle is of great importance since it aims at reducing process costs while increasing product quality of this time-and-energy-consuming process. Mathematical modeling comes as a tool to help a better understanding of the process variables behavior and consequently it helps optimization studies. Freeze-drying microscopy is a technique usually applied to determine critical temperatures of liquid formulations. It has been used in this work to determine the sublimation rates of a biological tissue freeze-drying. The sublimation rates were measured from the speed of the moving interface between the dried and the frozen layer under 21.33, 42.66 and 63.99 Pa. The studied variables were used in a theoretical model to simulate various temperature profiles of the freeze-drying process. Good agreement between the experimental and the simulated results was found.

A prática da transplantação traz esperança para muitos pacientes. Uma visão multidisciplinar nessa área visa à produção de tecidos biológicos para serem utilizados como implantes e próteses. A liofilização é um processo de secagem que preserva características essenciais desses materiais, facilitando sua manipulação e armazenamento. A liofilização é um processo que requer muito tempo e energia e sua otimização é muito importante, pois permite reduzir custos de processo melhorando a qualidade do produto. A modelagem matemática é uma ferramenta que permite descrever o comportamento do produto durante o processo e, consequentemente, auxilia os estudos de otimização. Microscopia óptica acoplada à liofilização, uma técnica usualmente aplicada na determinação de temperaturas críticas de formulações líquidas, foi utilizada neste trabalho na determinação de taxas de sublimação da liofilização de um tecido biológico. As taxas de sublimação foram calculadas a partir da velocidade da interface entre a camada seca e congelada, sob pressões de 21,33, 42,66 e 63,99 Pa. As variáveis estudadas foram usadas em um modelo matemático teórico, que simula os perfis de temperatura do produto durante o ciclo de liofilização. Os resultados apresentados demonstraram boa relação entre os dados experimentais e simulados.

Arc-to-arc mini-sling 1999: a critical analysis of concept and technology

PURPOSE: The aim of this study was to critically review the Arc-to-Arc mini-sling (Palma's technique) a less invasive mid-urethral sling using bovine pericardium as the sling material. MATERIALS AND METHODS: The Arc-to-Arc mini-sling, using bovine pericardium, was the first published report of a mini-sling, in 1999. The technique was identical to the "tension-free tape" operation, midline incision and dissection of the urethra. The ATFP (white line) was identified by blunt dissection, and the mini-sling was sutured to the tendinous arc on both sides with 2 polypropylene 00 sutures. RESULTS: The initial results were encouraging, with 9/10 patients cured at the 6 weeks post-operative visit. However, infection and extrusion of the mini-sling resulted in sling extrusion and removal, with 5 patients remaining cured at 12 months. CONCLUSION: The Arc-to-Arc mini-sling was a good concept, but failed because of the poor technology available at that time. Further research using new materials and better technology has led to new and safer alternatives for the management of stress urinary incontinence.

Experiment study of the acellular bovine pericardium treated by dye-mediated photooxidation used as engineering heart tissue / 中华胸心血管外科杂志

ObjectiveTo evaluate the feasibility of constructing tissue engineering cardiac patch with photooxidationfixed acellular bovine pericardium.MethodsFresh bovine pericardia were treated by dye-mediated photooxidation after decellularization.Some of them were seeded with bone marrow stromal cells(MSCs) isolated from male SD rats to construct cardiac patches.Myocardial infarction(MI) model was made in female SD rats by left anterior descending coronary ligation(LAD).One week later, the confirmed MI rats were divided into three groups randomly, group MI (n = 15)without any treatment; group P (n = 18) with photooxidated pericardia implantation ; group P + C (n = 18) with seeded pericardia implantation.A sham group (n = 10) was also performed with opening and closing chest twice only.The heart were explanted at 2 or 4 weeks after implantation, and examined histologically and immunohistochemically.The heart function was evaluated by echocardiography at 4 weeks before excising the rats.ResultsThere were no cells or cell debris remained in bovine pericardium tissue.The fiber structure became condensed after photooxidation.The seeded cells formed a continuous layer on the surface of the tissue.The pericardial degradation level and newly formed microvessel density were larger in group P + C than in group P after 2 [ (13.7 ±5.2)个/mm2 vs (7.1 ±3.1)个/mm2, P＜0.05]and4 [(22.6 ±4.9)个/mrn2 vs (14.1 ±5.3)个/mm2, P＜0.05]weeks.Four weeks after transplantation, cardiac echocardiography showed left ventricular ejection fraction(LVEF) was lower in group MI (44.8 ± 4.4) ％ and group P (48.4 ± 5.0) ％ compared with group P + C (49.3 ± 4.8) ％, left ventricular fractional shorterning(LVFS) was lower in group MI (18.0 ± 2.2) ％ and group P (19.8 ± 2.5) ％ compared with group P + C (20.4 ±2.5) ％, the difference between P + C and MI was significant.ConclusionTransplantation of the tissue engineered bovine pericardial patches with dye-mediated photooxidation can improve heart function in MI rats.This kind of patches demonstrates a promising prospect in the future.

The influence of freezing rates on bovine pericardium tissue Freeze-drying

The bovine pericardium has been used as biomaterial in developing bioprostheses. Freeze-drying is a drying process that could be used for heart valve's preservation. The maintenance of the characteristics of the biomaterial is important for a good heart valve performance. This paper describes the initial step in the development of a bovine pericardium tissue freeze-drying to be used in heart valves. Freeze-drying involves three steps: freezing, primary drying and secondary drying. The freezing step influences the ice crystal size and, consequently, the primary and secondary drying stages. The aim of this work was to investigate the influence of freezing rates on the bovine pericardium tissue freeze-drying parameters. The glass transition temperature and the structural behaviour of the lyophilized tissues were determined as also primary and secondary drying time. The slow freezing with thermal treatment presented better results than the other freeze-drying protocols.

O pericárdio bovino é um material utilizado na fabricação de biopróteses. A liofilização é um método de secagem que vem sendo estudado para a conservação de válvulas cardíacas. A preservação das características do biomaterial é de fundamental importância no bom funcionamento das válvulas. Este artigo é a primeira etapa do desenvolvimento do ciclo de liofilização do pericárdio bovino. Liofilização é o processo de secagem no qual a água é removida do material congelado por sublimação e desorção da água incongelável, sob pressão reduzida. O congelamento influencia o tamanho do cristal de gelo e, consequentemente, a secagem primária e secundária. O objetivo deste estudo foi verificar a influência das taxas de congelamento nos parâmetros de liofilização do pericárdio bovino. Determinou-se a temperatura de transição vítrea e o comportamento estrutural do pericárdio bovino liofilizado. Determinou-se o tempo da secagem primária e secundária. O protocolo de liofilização utilizando-se congelamento lento com annealing apresentou os melhores resultados.

Corporoplasty using bovine pericardium grafts in complex penile prosthesis implantation surgery

Purpose: This paper is the first, to our knowledge, to propose the use of a bovine pericardium graft in corporoplasty for penile prosthesis implantation. The advantages of bovine pericardium graft have been demonstrated by its use in cardiac surgery, including low cost, biocompatibility, impermeability, resistance to dilatation, flexibility, low likelihood of retraction, absence of antigenic reaction and natural absorption of the tissue. In this paper, we propose the use of this heterologous material graft in corporoplasty for penile prosthesis implantation. Materials and Methods: Five patients with a history of erosion, infection and fibrosis, mean time of follow-up 32 months (range 9-48 months). Bovine pericardium was used to cover large areas of implanted penile prostheses when use of the tunica albuginea was unfeasible. Results: The surgical procedure resulted in no complications in all patients. Conclusions: Bovine pericardium may substitute synthetic and autologous material with the additional advantages of lower cost and greater availability.

Feasibility Assessment of Interposition Vessel Graft Substitutes in Dog Models for Later Clinical Application to Middle Hepatic Vein Reconstruction during Living Donor Liver Transplantation

PURPOSE: Most of grafts used as interposition conduits for middle hepatic vein (MHV) in living donor liver transplantation (LDLT) have been allografts and autografts. Recently, polytetrafluoroethylene (PTFE) and bovine pericardium patch have also been used. Thus, we performed large-animal lab tests to assess the feasibility of interposition vessel graft substitutes for MHV. METHODS: The inferior vena cava was replaced in 9 dogs with allograft (3), PTFE (3), and bovine pericardium patch (3). After 28 days, patency rate, outer and inner diameter, intimal thickness, histology, and immunohistochemistry were evaluated according to interposition grafts. RESULTS: The allograft and PTFE groups were all patent at post-operative week 4, but the bovine group was not patent in all dogs. Outer diameter of anastomotic site at 4 weeks was 8.41+/-0.37, 10.83+/-0.51, and 7.41+/-0.86 mm in allograft, PTFE, and bovine group, respectively. Inner diameter of interposition graft at 4 weeks was 7.90+/-0.23, 6.33+/-0.68, and 0 mm in allograft, PTFE, and bovine groups, respectively. Intimal thickness was 48.0+/-8.6, 113.8+/-45.3, and 218.3+/-59.9microm in allograft, PTFE, and bovine groups, respectively. In histologic findings, inflammation was most severe in the bovine group. Intima of anastomotic site in the bovine group was thickest in all groups. Proliferation of smooth muscle cells was most severe in anti-alpha-actin antibody test in bovine group. CONCLUSION: Our data implicate that the use of allografts and PTFE grafts is more feasible than bovine pericardium for MHV reconstruction in LDLT.

Otimização da liofilização do pericárdio bovino com o auxílio de ferramentas matemáticas / Freeze-drying optimization of bovine pericardium by mathematical modelingFreeze-drying optimization of bovine pericardium by mathematical modeling

A liofilização é um método de conservação utilizado para a obtenção de produtos desidratados de alta qualidade. É um processo que requer tempo e energia, podendo levar dias para terminar se o ciclo de liofilização não for otimizado. O objetivo da otimização do processo de liofilização é minimizar o consumo de energia e reduzir o tempo de processo, sem que ocorra a perda na qualidade do produto liofilizado. A utilização de modelos matemáticos que predizem o comportamento do produto durante a liofilização pode reduzir drasticamente o número de experimentos, além de determinar variáveis importantes que não podem ser medidas experimentalmente. Tecidos biológicos são produtos sensíveis que se submetidos à altas temperaturas podem sofrer alterações irreversíveis. O estudo da liofilização do pericárdio bovino tem como objetivo sua conservação, facilitando sua manipulação e armazenamento. O objetivo deste projeto foi o uso da teoria fenomenológica que envolve a liofilização, com a utilização de parâmetros essenciais determinados por experimentos de laboratório, para guiar o desenvolvimento de um modelo matemático capaz de descrever a dinâmica do processo de liofilização do pericárdio bovino para, através de seu estudo e da análise das características do produto liofilizado, alcançar a validação do processo. O estudo do congelamento na liofilização do pericárdio bovino foi feito, determinando-se os tempos de processo e o conteúdo de umidade residual do produto seco. A modelagem matemática do processo foi apresentada a partir da determinação de taxas de sublimação por microscopia óptica acoplada à liofilização, sob diferentes pressões de câmara e taxas de aquecimento de placa. Os produtos liofilizados foram avaliados quanto à manutenção de suas propriedades físicas. Os resultados mostraram que o congelamento lento com tratamento térmico apresentou curto tempo de liofilização e baixo valor de umidade residual do produto final. O modelo matemático demonstrou a...

Freeze-drying is a method of preservation that provides high-quality dehydrated products. It is a process that requires time and energy and it may take days to finish. Freeze-drying optimization is used to minimize the process time keeping the high quality of the product. Mathematical models that predict the behavior of products during freeze-drying can drastically reduce the number of experiments and determine variables in a study that could not be experimentally measured. Biological tissues are sensitive to heat and might be irreversibly modified. The study of bovine pericardium freeze-drying improves its handling and storage. The purpose of this project was to determine key parameters which served to guide the development of a mathematical model able to describe the bovine pericardium freeze-drying process and achieve its validation. The study of the freezing step in the bovine pericardium freeze-drying was done by analyzing the time of the process and the residual moisture content of the dried product. Mathematical modeling of the process was shown from the determination of sublimation rates by freeze-drying microscopy under different chamber pressures and heating rates. The freeze-dried products were evaluated for the maintenance of their physical properties. The results revealed that slow freezing with thermal treatment had short process time and low residual moisture of the final product. The mathematical model demonstrated the bovine pericardium freeze-drying and the product indicated no change in their physical properties after the process. Thus, the freeze-drying microscopy analysis was validated in determining the sublimation rate during the bovine pericardium freeze-drying and the process was endorsed through mathematical modeling

Bovine pericardium as a lasting option tocorrect agenesis of the left hemidiaphragm:a five years follow-up / Uso do pericárdio bovino como opção duradoura para a correção da agenesia do hemidiafragma esquerdo: seguimento de cinco anos

Different surgical approaches for large congenital diaphragmatic defects have been described in the last fifity years. Synthetic patches have been proposed but have not always lead to good results due to reherniations, absence of growth of the patch, and future definitive operations. Few options of biological patches to reconstruct those large congenital defects are described in the literature, such as: dorsal muscle flap, lyophilized dura patch, small intestine submucosa and autologous fascia lata. There was no report of bovine pericardium patches as an alternative to treat congenital defects such as the total agenesis of the left hemidiaphragm, although experimental studies has shown that bovine pericardium seemed to be a very safe and resistant material to used in this congenital defect. We present a 4-years old girl that was re-operated with a patch of glutaraldehyde-preserved bovine pericardium after Silistic® patch had failed twice when she was born. We hypothesized that the bovine pericardium patch would be a lasting alternative to reconstruct agenesis of the left hemidiaphragm in this patient because of the attributes of the material: strength, elasticity, resistance to sutures and the possibility of growth. The aim of this communication is to present this biological material as a better and long-term alternative for correction of large congenital diaphragmatic defects, since our patient completed four years after the procedure without any deformities or respiratory complications.

Várias abordagens cirúrgicas têm sido descritas nos últimos cinqüenta anos para a correção dos grandes defeitos congênitos do diafragma. Material sintético tem sido proposto, mas não tem apresentado bons resultados devido às recidivas do defeito. O remendo sintético não cresce com a criança e apresenta necessidade de futuras reoperações. Poucas opções de materiais biológicos vêm sendo descritas na literatura para a correção dos grandes defeitos congênitos do diafragma, como: retalho muscular dorsal, duramáter liofilizada, submucosa de intestino delgado e fáscia lata autóloga. Não existem relatos na literatura a respeito do pericárdio bovino como opção ao tratamento dos defeitos congênitos do diafragma como agenesia total do hemidiafragma esquerdo, embora estudos experimentais mostram que o pericardium bovino parece ser material seguro e resistente que pode ser usado neste defeito congênito. Este é o relato de uma menina de 5 anos de idade que foi reoperada com remendo biológico de pericárdio bovino preservado em glutaraldeído, aos 4 meses de idade após duas tentativas frustradas de correção com remendo sintético (silicone). Os autores acreditam que o remendo de pericárdio bovino poderia ser opção mais duradoura para a correção da agenesia total do hemidiafragma esquerdo nesses pacientes devido às suas vantagens, como forte estrutura do material, elasticidade, resistência a suturas e possibilidade de crescimento. O objetivo deste relato é apresentar esse material biológico como melhor escolha, mais duradoura para correção dos grandes defeitos congênitos do diafragma, já que a criança completou quatro anos após o procedimento sem apresentar deformidade e ou complicações respiratórias.

Repair of Full-thickness Defects in the Alimentary Tract Wall with a Bovine Pericardium Patch and Glue

PURPOSE: The authors performed this experimental study to test the efficacy and possibility of using a bovine pericardial patch (BPP) with Histoacryl(R) glue for the repair of full-thickness defects in the alimentary tract wall of a mouse model. METHODS: The animal study was conducted under aseptic conditions using 20 rats (4-week-old, 250~300 g each). Rats with a BPP with Histoacryl(R) glue were used to evaluate the effectiveness, strength, adhesion formation, morphological changes, early complications and changes of the BPP character. We made a tube--like form with BPP and Histoacryl(R); we put it in saline (NaCl 0.9%), gastric juices and bile for 2 weeks to test the changes in the material and the strength of the attachment. We tested the BPP with glue attached to the full-thickness defects in the alimentary tract wall. After 3 weeks we scarified the mice and analyzed the patch attachment and microscopic finding. RESULTS: The attached BPP with Histoacryl(R) was put in saline (NaCl 0.9%), gastric juices and bile for 2 weeks, and there were no changes. The attached BPP with glue to the liver surface remained secure. There were no patch failures. We found just one significant adhesion with fibrosis in the surround tissue. But all the other animals mucosal healing was complete in 3 weeks. CONCLUSIONS: BPP with Histoacryl(R) glue may be an acceptable membrane for at least temporary repair of full-thickness defects in the alimentary tract wall. Further study is required.

Bile Duct Replacement Using Bovine Pericardial Patch Graft: an Experimental Study

PURPOSE: The repair of common bile duct injuries is a complex procedure that has a significant rate of postoperative morbidity and mortality. The aim of this study was to demonstrate the usefulness of the bovine pericardial patch (BPP) graft for replacement of the bile duct. METHODS: In this study, BPP with Indermil glue was used to evaluate the effectiveness, morphological changes, early complications and changes of BPP's character. Four male pigs weighing 30~40 kg each were used in the study. We attached a BPP on the small size defected common bile duct (CBD) surface of one pig with using Indermil glue. Another pig's segment of the CBD was resected and the biliary tract was replaced by a tube formed from BPP. After 2 weeks, these animals were sacrificed and we analyzed the patch attachment, the cholangiography and morphological changes. RESULTS: We made a tube-like form from BPP with Indermil; we put it into saline (NaCl 0.9%), gastric juices and bile for 2 weeks to test the changes of the material and the strength of the attachment. Nothing changed, and the attachment remained secure. After 2 weeks these animal were sacrificed and the patch attachment was evaluated by cholangiography and the morphological changes. One significant adhesion with fibrosis in surrounding tissue was noted with obstruction of the CBD. CONCLUSION: These observations suggest that BPP with Indermil glue may well be an acceptable membrane in CBD replacement.