In vitro evaluation of membranes for regenerative procedures against oral bacteria

Abstract The current literature on guided bone regeneration (GBR) and guided tissue regeneration (GTR) membrane contamination reports that the physicochemical characteristics of these biomaterials might influence affinity to bacteria, which appears to be a major drawback for the clinical outcome of the regenerative procedures. Thus, this study aimed to evaluate, in vitro, a multispecies biofilm adherence and passage of bacteria through different types of commercially available membranes for GTR/GBR. Four types of membranes were tested (n=12): LC) Lumina Coat®; JS) Jason®; BG) Biogide®; and LP) Lumina PTFE®. Aluminum foil (AL) simulated an impermeable barrier and was used as the control. The membranes were adapted to specific apparatus and challenged with a mixed bacterial culture composed of A. actinomycetemcomitans b, S. mutans, S. mitis, and A. israelii. After 2 h or 7 days, bacterial adhesion and passage of bacteria were evaluated through CFU counting, which was analyzed by two-way ANOVA e post hoc Tukey, at a 5% significance level. Representative areas of two membranes of each group were analyzed through scanning electron microscopy (SEM) to assess the morphology and organization of the biofilm over the membrane fibers. LC and LP presented similar values of adhered bacterial cells (p > 0.05), significantly inferior when compared to the other groups, in both time points (p < 0.05). All the tested groups were permeable to bacterial cells, with no significant difference between the trial period of 2 h and 7 days (p > 0.05). SEM analyses demonstrated that adhered bacteria number increased throughout the time points (2 h < 7 days). Commercially available biological membranes demonstrated intense bacterial adherence and passage of bacteria, which increased throughout the trial period.

Resumo O objetivo deste estudo foi avaliar, in vitro, a aderência do biofilme multiespécie e a passagem de bactérias através dos diferentes tipos de membranas disponíveis comercialmente para RTG/ROG. Quatro tipos de membranas foram testados (n=12): LC) Lumina Coat®; JS) Jason®; BG) Biogide®; e LP) Lumina PTFE®. Papel alumínio (AL) simulou uma barreira impermeável e foi usado como controle negativo. As membranas foram adaptadas à um aparato específico e desafiadas com uma cultura bacteriana mista composta de A. actinomycetemcomitans b, S. mutans, S. mitis, e A. israelii. Após 2 h ou 7 dias, a aderência e passagem bacteriana foi avaliada através da contagem de UFCs. Duas membranas de cada grupo foram analisadas através da microscopia eletrônica de varredura (MEV). LC e LP apresentaram valores semelhantes de células bacterianas aderidas (p < 0.05), significativamente inferiores quando comparados aos outros grupos, em ambos os períodos experimentais (p < 0.05). Desde a análise inicial, todos os grupos testados foram permeáveis às células bacterianas, sem diferença significativa entre o período experimental de 2 h e 7 dias (p > 0.05). As análises em MEV demonstraram que o número de bactérias aderidas aumentou com o tempo (2 h < 7 days). Membranas biológicas comercialmente disponíveis demonstraram intensa aderência bacteriana e passagem de bactérias, que aumentou durante os períodos experimentais.

Comparative study of bullfrog (Rana catebeiana) skin preservation for use as a biomaterial / Estudo comparativo de meios de conservação de pele de rã-touro (Rana catesbeiana) para utilização como biomaterial

The use of biological membranes in wound dressings has increasingly become a reality. Accordingly, an ideal means of preservation is sought that can provide tissue maintenance for long periods without interfering with its quality or clinical applicability. Therefore, the objective of the present study was to evaluate and histologically and microbiologically compare frog skins subjected to two different preservation methods. Sixteen frog skins were evaluated and, depending on the preservation method, subdivided into two groups with eight skins each, namely, the Freezing Group, in which the skins were frozen at -4º in a 20% glycerin solution; and the Glycerin Group, whose skins were kept in 98% glycerin at room temperature (average of 28 ºC and average humidity of 78%). The skins were analyzed fresh (T0) and at 30 (T1), 60 (T2), 90 (T3), and 120 (T4) days of preservation. Data were analyzed comparatively. There was no bacterial or fungal growth, and the skin structure and collagen arrangement remained intact at all time points in both treatments. In conclusion, both preservation methods are efficient and capable of maintaining the tissue morphological structure and preventing the growth and proliferation of contaminants for up to 120 days.

A utilização de membranas biológicas em curativos tem se tornado cada vez mais uma realidade. Concomitante, busca-se um meio de conservação ideal que possa proporcionar a manutenção do tecido por longos períodos de tempo sem interferir em sua qualidade e aplicabilidade clínica. Desta forma, o objetivo deste trabalho foi o de avaliar e comparar histologicamente e microbiologicamente peles de rã submetidas a dois diferentes métodos de conservação. Foram avaliadas 16 peles de rã-touro as quais foram, em função do método de conservação, subdivididas em dois grupos com 08 peles cada: O Grupo Congelamento (GC) no qual as peles foram submetidas ao congelamento a -4º, em solução de glicerina a 20%; e o grupo Glicerina (GG), no qual as peles foram conservadas em temperatura ambiente (média de 28ºC e umidade média de 78%) em glicerina a 98%. As peles foram analisadas a fresco (T0) e com 30 (T1), 60 (T2), 90 (T3) e 120 (T4) dias de conservação. Os dados foram analisados de forma comparativa. Em todos os tempos analisados e em ambos os tratamentos, não houve crescimento bacteriano ou fúngico e a estrutura da pele e o arranjo de colágeno mantiveram-se íntegros. Conclui-se que, ambos os métodos de conservação são eficientes e capazes de manter a estrutura morfológica tecidual, e impedem o crescimento e a proliferação de contaminantes por até 120 dias.

Stepwise Protocols for Preparation and Use of Porcine Ear Skin for in Vitro Skin Permeation Studies Using Franz Diffusion Cells.

The skin, the largest organ of the body, is an attractive route of topical and systemic drug administration. During the development of topical formulations, in vitro skin permeation studies using biological membranes mounted in Franz diffusion cells are a useful tool to assess the permeation of substances through the skin, and are recommended by the Organization for Economic Cooperation and Development (OECD). Among the types of biological membranes used in such studies, porcine ear skin has been identified as the most promising, due to its similarities to human skin and its greater accessibility as compared to human skin. To standardize techniques for the preparation and use of porcine ear skin as biological membrane, here we present systematic procedures for the selection of porcine ears, their cleaning, the removal of skin from cartilage, its transformation into membranes, and its use for the in vitro assessment of the permeation of drugs from topical formulations. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Obtaining porcine ear membranes Basic Protocol 2: Preparation of membranes from porcine ear skin and use of membranes for in vitro skin permeation studies.

Interaction of cationic surfactants with DPPC membranes: effect of a novel Nα-benzoylated arginine-based compound.

Cationic amino acid-based surfactants are known to interact with the lipid bilayer of microorganism resulting in cell death through a disruption of the membrane topology. To elucidate the interaction of a cationic surfactant synthesized in our lab, investigations involving Nα-benzoyl-arginine decyl amide (Bz-Arg-NHC10), and model membranes composed by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) were done. Bz-Arg-NHC10was able to penetrate into DPPC monolayers up to a critical pressure of 59.6 mN m-1. Differential scanning calorimetry revealed that as the concentration of Bz-Arg-NHC10 increased, the main transition temperature of DPPC slightly decreased. Atomic force microscopy (AFM) in situ experiments performed on supported DPPC bilayers on mica allowed monitoring the changes induced by Bz-Arg-NHC10. DPPC bilayer patches were partially removed, mainly in borders and bilayer defects for 50 µM Bz-Arg-NHC10 solution. Increasing the concentration to 100 µM resulted in a complete depletion of the supported bilayers. Surface plasmon resonance (SPR) experiments, carried out with fully DPPC bilayers covered chips, showed a net increase of the SPR signal, which can be explained by Bz-Arg-NHC10 adsorption. When patchy DPPC bilayers were formed on the substrate, a SPR signal net decrease was obtained, which is consistent with the phospholipids' removal observed in the AFM images. The results obtained suggest that the presence of the benzoyl group attached to the polar head of our compound would be the responsible of the increased antimicrobial activity against gram-negative bacteria when compared with other arginine-based surfactants.

A Reevaluation of Chitosan-Decorated Nanoparticles to Cross the Blood-Brain Barrier.

The blood-brain barrier (BBB) is a sophisticated and very selective dynamic interface composed of endothelial cells expressing enzymes, transport systems, and receptors that regulate the passage of nutrients, ions, oxygen, and other essential molecules to the brain, regulating its homeostasis. Moreover, the BBB performs a vital function in protecting the brain from pathogens and other dangerous agents in the blood circulation. Despite its crucial role, this barrier represents a difficult obstacle for the treatment of brain diseases because many therapeutic agents cannot cross it. Thus, different strategies based on nanoparticles have been explored in recent years. Concerning this, chitosan-decorated nanoparticles have demonstrated enormous potential for drug delivery across the BBB and treatment of Alzheimer's disease, Parkinson's disease, gliomas, cerebral ischemia, and schizophrenia. Our main objective was to highlight the high potential of chitosan adsorption to improve the penetrability through the BBB of nanoformulations for diseases of CNS. Therefore, we describe the BBB structure and function, as well as the routes of chitosan for crossing it. Moreover, we define the methods of decoration of nanoparticles with chitosan and provide numerous examples of their potential utilization in a variety of brain diseases. Lastly, we discuss future directions, mentioning the need for extensive characterization of proposed nanoformulations and clinical trials for evaluation of their efficacy.

Coupled Response of Membrane Hydration with Oscillating Metabolism in Live Cells: An Alternative Way to Modulate Structural Aspects of Biological Membranes?

We propose that active metabolic processes may regulate structural changes in biological membranes via the physical state of cell water. This proposition is based on recent results obtained from our group in yeast cells displaying glycolytic oscillations, where we demonstrated that there is a tight coupling between the oscillatory behavior of glycolytic metabolites (ATP, NADH) and the extent of the dipolar relaxation of intracellular water, which oscillates synchronously. The mechanism we suggest involves the active participation of a polarized intracellular water network whose degree of polarization is dynamically modulated by temporal ATP fluctuations caused by metabolism with intervention of a functional cytoskeleton, as conceived in the long overlooked association-induction hypothesis (AIH) of Gilbert Ling. Our results show that the polarized state of intracellular water can be propagated from the cytosol to regions containing membranes. Since changes in the extent of the polarization of water impinge on its chemical activity, we hypothesize that metabolism dynamically controls the local structure of cellular membranes via lyotropic effects. This hypothesis offers an alternative way to interpret membrane related phenomena (e.g., changes in local curvature pertinent to endo/exocytosis or dynamical changes in membranous organelle structure, among others) by integrating relevant but mostly overlooked physicochemical characteristics of the cellular milieu.

Reparação cirúrgica de fenda palatina em potro com a utilização de pericárdio bovino: relato de caso / Surgical correction of cleft palate in foal using bovine pericardium: case report / Corrección quirúrgica del paladar hendido en potro con pericardio bovino: reporte de un caso

Este artigo tem como objetivo relatar o caso de reparação cirúrgica de uma fenda palatina congênita em uma potra com a utilização de pericárdio bovino conservado em glicerina a 98%. Um equino, fêmea, com 6 dias de vida foi atendido em uma propriedade apresentando dificuldade de deglutição e refluxo de leite pelas narinas, o qual foi diagnosticado com fenda palatina secundária. O animal foi submetido a palatoplastia com acesso cirúrgico por bucotomia lateral, porém 5 dias após o procedimento, houve deiscência da sutura. Optou-se então pela utilização de membrana biológica para a reconstrução do palato. O acesso a cavidade bucal por bucotomia possibilitou a sutura da fenda palatina e a colocação de pericárdio bovino com adesivo tecidual de etil-cianoacrilato. A técnica utilizada mostrou-se eficiente, uma vez que o animal apresentou boa adaptação e não houve deiscência de pontos após a segunda intervenção. A utilização de pericárdio bovino mostrou-se viável nesse caso palatoplastia, visto que a não realização da reconstrução torna-se incompatível a manutenção da vida.

This paper aims to report a case of surgical repair of congenital cleft palate in foal using bovine pericardium preserved in glycerin 98%. One female horse, with 6 days of life examined at the property with difficulty swallowing and milk reflux nostrils, which was diagnosed with secondary cleft palate. The animal was subjected to palatoplasty with surgical access by bucotomia, but five days after the procedure, there was suture dehiscence. It was then decided by the use of biological membrane for the reconstruction of the palate. Access to the oral cavity by bucotomia possible suturing the cleft palate and placement of bovine pericardium with tissue adhesive the basis of ethyl-cyanoacrylate. The technique used was efficient, since the animal showed good adaptation and no dehiscence points after the second intervention. Thus demonstrating a use a viable option bovine pericardium in palatoplasty surgeries since missing the reconstruction becomes inconsistent maintenance of life.

Este artículo tiene como objetivo informar el caso de reparación quirúrgica de un paladar hendido congénito en un potro utilizando pericardio bovino preservado con glicerina 98%. Una potra de 6 días de edad fue tratada en una granja con dificultad para tragar y reflujo de leche a través de las fosas nasales, que fue diagnosticada como paladar hendido secundario. El animal se sometió a una palatoplastia con acceso quirúrgico por bucotomía lateral, pero 5 días después del procedimiento, hubo dehiscencia de sutura. Luego se decidió utilizar una membrana biológica para la reconstrucción del paladar, el acceso a la cavidad bucal por bucotomía permitió suturar el paladar hendido y colocación de pericardio bovino con adhesivo tisular de cianoacrilato de etilo. La técnica utilizada demostró ser eficiente, una vez que el animal mostró una buena adaptación y no hubo dehiscencia de puntos después de la segunda intervención. EI uso de pericardio bovino fue viable eneste caso de palatoplastia, ya que la realización de la reconstrucción se vuelve incompatible con el mantenimiento de la vida.

Reparação cirúrgica de fenda palatina em potro com a utilização de pericárdio bovino: relato de caso / Surgical correction of cleft palate in foal using bovine pericardium: case report / Corrección quirúrgica del paladar hendido en potro con pericardio bovino: reporte de un caso

Este artigo tem como objetivo relatar o caso de reparação cirúrgica de uma fenda palatina congênita em uma potra com a utilização de pericárdio bovino conservado em glicerina a 98%. Um equino, fêmea, com 6 dias de vida foi atendido em uma propriedade apresentando dificuldade de deglutição e refluxo de leite pelas narinas, o qual foi diagnosticado com fenda palatina secundária. O animal foi submetido a palatoplastia com acesso cirúrgico por bucotomia lateral, porém 5 dias após o procedimento, houve deiscência da sutura. Optou-se então pela utilização de membrana biológica para a reconstrução do palato. O acesso a cavidade bucal por bucotomia possibilitou a sutura da fenda palatina e a colocação de pericárdio bovino com adesivo tecidual de etil-cianoacrilato. A técnica utilizada mostrou-se eficiente, uma vez que o animal apresentou boa adaptação e não houve deiscência de pontos após a segunda intervenção. A utilização de pericárdio bovino mostrou-se viável nesse caso palatoplastia, visto que a não realização da reconstrução torna-se incompatível a manutenção da vida.(AU)

This paper aims to report a case of surgical repair of congenital cleft palate in foal using bovine pericardium preserved in glycerin 98%. One female horse, with 6 days of life examined at the property with difficulty swallowing and milk reflux nostrils, which was diagnosed with secondary cleft palate. The animal was subjected to palatoplasty with surgical access by bucotomia, but five days after the procedure, there was suture dehiscence. It was then decided by the use of biological membrane for the reconstruction of the palate. Access to the oral cavity by bucotomia possible suturing the cleft palate and placement of bovine pericardium with tissue adhesive the basis of ethyl-cyanoacrylate. The technique used was efficient, since the animal showed good adaptation and no dehiscence points after the second intervention. Thus demonstrating a use a viable option bovine pericardium in palatoplasty surgeries since missing the reconstruction becomes inconsistent maintenance of life.(AU)

Este artículo tiene como objetivo informar el caso de reparación quirúrgica de un paladar hendido congénito en un potro utilizando pericardio bovino preservado con glicerina 98%. Una potra de 6 días de edad fue tratada en una granja con dificultad para tragar y reflujo de leche a través de las fosas nasales, que fue diagnosticada como paladar hendido secundario. El animal se sometió a una palatoplastia con acceso quirúrgico por bucotomía lateral, pero 5 días después del procedimiento, hubo dehiscencia de sutura. Luego se decidió utilizar una membrana biológica para la reconstrucción del paladar, el acceso a la cavidad bucal por bucotomía permitió suturar el paladar hendido y colocación de pericardio bovino con adhesivo tisular de cianoacrilato de etilo. La técnica utilizada demostró ser eficiente, una vez que el animal mostró una buena adaptación y no hubo dehiscencia de puntos después de la segunda intervención. EI uso de pericardio bovino fue viable eneste caso de palatoplastia, ya que la realización de la reconstrucción se vuelve incompatible con el mantenimiento de la vida.(AU)

Biophysical approaches in the study of biomembrane solubilization: quantitative assessment and the role of lateral inhomogeneity.

Detergents are amphiphilic molecules widely used to solubilize biological membranes and/or extract their components. Nevertheless, because of the complex composition of biomembranes, their solubilization by detergents has not been systematically studied. In this review, we address the solubilization of erythrocytes, which provide a relatively simple, robust and easy to handle biomembrane, and of biomimetic models, to stress the role of the lipid composition on the solubilization process. First, results of a systematic study on the solubilization of human erythrocyte membranes by different series of non-ionic (Triton, CxEy, Brij, Renex, Tween), anionic (bile salts) and zwitterionic (ASB, CHAPS) detergents are shown. Such quantitative approach allowed us to propose Resat-the effective detergent/lipid molar ratio in the membrane for the onset of hemolysis as a new parameter to classify the solubilization efficiency of detergents. Second, detergent-resistant membranes (DRMs) obtained as a result of the partial solubilization of erythrocytes by TX-100, C12E8 and Brij detergents are examined. DRMs were characterized by their cholesterol, sphingolipid and specific proteins content, as well as lipid packing. Finally, lipid bilayers of tuned lipid composition forming liposomes were used to investigate the solubilization process of membranes of different compositions/phases induced by Triton X-100. Optical microscopy of giant unilamellar vesicles revealed that pure phospholipid membranes are fully solubilized, whereas the presence of cholesterol renders the mixture partially or even fully insoluble, depending on the composition. Additionally, Triton X-100 induced phase separation in raft-like mixtures, and selective solubilization of the fluid phase only.

Implantes de membranas biológicas en cirugía reconstructiva veterinaria: aspectos básicos y métodos de conservación / Biological membrane implants in veterinary reconstructive surgery: Basic aspects and conservation methods / Implantes de membranas biológicas em cirurgia reconstrutiva veterinária: aspectos básicos e métodos de conservação

Las membranas biológicas se emplean como implantes en cirugía veterinaria reconstructiva con el objetivo de restablecer la función y la estructura de tejidos dañados. Diversos tejidos obtenidos de animales, conservados por diferentes técnicas e implantados en receptores de la misma o de diferente especie, permiten reparar heridas en las que es evidente la extensa pérdida tisular o la imposibilidad de inducir cicatrización por primera intención. Aunque las bondades de las membranas biológicas son mayores que sus desventajas, su uso en la rutina clínica y quirúrgica no es frecuente, en gran parte por el desconocimiento de sus características, manipulación e implantación. La presente revisión pretende recopilar los aspectos generales que envuelven las membranas biológicas, desde su obtención hasta las posibles complicaciones de su uso, a través de estudios experimentales y reportes de caso relatados con anterioridad, e incentivar su uso como biomaterial de implante en defectos anatómicos, heridas traumáticas, postoperatorios oncológicos y traumas en general.

Biological membranes are used as implants in veterinary reconstructive surgery in order to restore the function and structure of damaged tissues. Various tissues from animals, kept by different techniques and implanted in recipients of the same or different species, help repair wounds where extensive tissue loss or the inability to scarring is evidenced. Although the benefits of biological membranes outweigh their disadvantages, their use in clinical and surgical routines is rare, largely due to ignorance of their characteristics, handling and implantation. The present article aims to review general aspects on biological membranes, from procurement to possible complications of their use, through experimental studies and previously reported cases, and to encourage their use as a biomaterial implant in case of anatomical defects, traumatic wounds, oncological postoperative care, and traumas in general.

As membranas biológicas se empregam como implantes em cirurgia veterinária reconstrutiva com o objetivo de restabelecer a função e a estrutura de tecidos destruídos. Diversos tecidos obtidos de animais, conservados por diferentes técnicas e implantados em receptores da mesma ou de diferente espécie, permitem reparar feridas aonde é evidente a extensa perda tissular ou a impossibilidade de induzir cicatrização por primeira intenção. Ainda que as bondades das membranas biológicas sejam maiores que suas desvantagens, seu uso na rotina clínica e cirúrgica não é frequente, em grande parte pelo desconhecimento de suas características, manipulação e implantação. Esta revisão pretende recopilar os aspectos gerais que envolvem as membranas biológicas, desde sua obtenção até as possíveis complicações de seu uso, através de estudos experimentais e relatórios de caso relatados com anterioridade, e incentivar seu uso como bio material de implante em defeitos anatômicos, feridas traumáticas, pós-operatórios oncológicos e traumas em geral.

Propriedades tensiométricas do peritônio da paca (Cuniculus paca) a fresco e conservado em glicerina 98 por cento / Tensiometer peritoneum properties of the paca (Cuniculus paca) fresh and preserved in glycerin 98 por cento

In constant searching for alternative biological material to perform implants and new options of experimental animal models, the objective of this investigation was to describe the mechanical properties of the peritoneum paca (Cuniculus paca Linnaeus, 1766) fresh and preserved in 98% glycerin. Samples of fresh and preserved in glycerin for periods of 30, 60 and 90 days were subjected to mechanical tests. Four adult animals, male or female, with mean body weight of eight kilograms, were used for collecting samples of the peritoneum. All tissues preserved in glycerin 98% showed a decrease in stiffness and increase in ductility and toughness. Considering the maximum force applied to the peritoneum, significant increase was observed in values (p<0.01) of samples stored for 60 and 90 days when compared to fresh material. In relation to the stretch variable, an increase was observed in all storage time of glycerin samples, verifying significant difference (p<0,01) when compared with the fresh samples. The variable area also showed significance (p <0.01) between the values of the fresh samples (5.40 mm²) and preserved in the glycerin by periods of 30 days (4.50 mm²), 60 days (9.00 mm²) and 90 days (7.20 mm²), thus indicating that the area of this membrane increased by 0.033 mm² per day. Generally, it was concluded that the 98% glycerin is a substance effective for the preservation of the peritoneum of the agouti paca, therefore improves its mechanical properties allowing the support membranes greater deformation forces. Thus, the results obtained in mechanical tests of the peritoneum of paca suggest its use as an alternative biological material.

Na busca constante, tanto de material biológico alternativo para a realização de implantes, quanto de novas opções de modelos de experimentação animal, o objetivo desta investigação foi descrever o comportamento mecânico do peritônio da paca (Cuniculus paca Linnaeus, 1766) a fresco e conservado em glicerina a 98%. Amostras frescas e conservadas em glicerina por períodos de 30, 60 e 90 dias foram submetidas a testes mecânicos de tração. Quatro animais adultos, três machos e uma fêmeas, com peso corporal médio de oito quilogramas, foram utilizados para colheita das amostras de peritônio. Todos os tecidos conservados em glicerina a 98% apresentaram diminuição na rigidez e aumento na ductibilidade e tenacidade. Considerando-se a força máxima aplicada ao peritônio, evidenciou-se aumento significativo nos valores (p<0,01) das amostras conservadas por 60 e 90 dias, quando comparado ao material a fresco. Com relação a variável alongamento, notou-se aumento nos valores relativos aos materiais em glicerina em todos os tempos de conservação, verificando-se diferença significativa (p<0,01) entre os valores das amostras a fresco. A variável área também se apresentou significativa (p<0,01) entre os valores das amostras a fresco (5,40 mm²) e os preservados em glicerina pelos períodos de 30 dias (4,50 mm²), 60 dias (9,00 mm²) e 90 dias (7,20 mm²), indicando assim, que a área desta membrana aumentou em 0,033 mm² por dia. Mediante os resultados observados, concluiu-se que a glicerina 98% é uma substância eficiente para a conservação do peritônio da paca, pois melhorou suas propriedades mecânicas permitindo que as membranas suportem maiores forças de deformação. Assim, os resultados obtidos nos ensaios mecânicos do peritônio da paca sugerem sua utilização como mais uma opção de material biológico.

Propriedades tensiométricas do peritônio da paca (Cuniculus paca) a fresco e conservado em glicerina 98 por cento / Tensiometer peritoneum properties of the paca (Cuniculus paca) fresh and preserved in glycerin 98 por cento

In constant searching for alternative biological material to perform implants and new options of experimental animal models, the objective of this investigation was to describe the mechanical properties of the peritoneum paca (Cuniculus paca Linnaeus, 1766) fresh and preserved in 98% glycerin. Samples of fresh and preserved in glycerin for periods of 30, 60 and 90 days were subjected to mechanical tests. Four adult animals, male or female, with mean body weight of eight kilograms, were used for collecting samples of the peritoneum. All tissues preserved in glycerin 98% showed a decrease in stiffness and increase in ductility and toughness. Considering the maximum force applied to the peritoneum, significant increase was observed in values (p<0.01) of samples stored for 60 and 90 days when compared to fresh material. In relation to the stretch variable, an increase was observed in all storage time of glycerin samples, verifying significant difference (p<0,01) when compared with the fresh samples. The variable area also showed significance (p <0.01) between the values of the fresh samples (5.40 mm²) and preserved in the glycerin by periods of 30 days (4.50 mm²), 60 days (9.00 mm²) and 90 days (7.20 mm²), thus indicating that the area of this membrane increased by 0.033 mm² per day. Generally, it was concluded that the 98% glycerin is a substance effective for the preservation of the peritoneum of the agouti paca, therefore improves its mechanical properties allowing the support membranes greater deformation forces. Thus, the results obtained in mechanical tests of the peritoneum of paca suggest its use as an alternative biological material.(AU)

Na busca constante, tanto de material biológico alternativo para a realização de implantes, quanto de novas opções de modelos de experimentação animal, o objetivo desta investigação foi descrever o comportamento mecânico do peritônio da paca (Cuniculus paca Linnaeus, 1766) a fresco e conservado em glicerina a 98%. Amostras frescas e conservadas em glicerina por períodos de 30, 60 e 90 dias foram submetidas a testes mecânicos de tração. Quatro animais adultos, três machos e uma fêmeas, com peso corporal médio de oito quilogramas, foram utilizados para colheita das amostras de peritônio. Todos os tecidos conservados em glicerina a 98% apresentaram diminuição na rigidez e aumento na ductibilidade e tenacidade. Considerando-se a força máxima aplicada ao peritônio, evidenciou-se aumento significativo nos valores (p<0,01) das amostras conservadas por 60 e 90 dias, quando comparado ao material a fresco. Com relação a variável alongamento, notou-se aumento nos valores relativos aos materiais em glicerina em todos os tempos de conservação, verificando-se diferença significativa (p<0,01) entre os valores das amostras a fresco. A variável área também se apresentou significativa (p<0,01) entre os valores das amostras a fresco (5,40 mm²) e os preservados em glicerina pelos períodos de 30 dias (4,50 mm²), 60 dias (9,00 mm²) e 90 dias (7,20 mm²), indicando assim, que a área desta membrana aumentou em 0,033 mm² por dia. Mediante os resultados observados, concluiu-se que a glicerina 98% é uma substância eficiente para a conservação do peritônio da paca, pois melhorou suas propriedades mecânicas permitindo que as membranas suportem maiores forças de deformação. Assim, os resultados obtidos nos ensaios mecânicos do peritônio da paca sugerem sua utilização como mais uma opção de material biológico.(AU)

Membranas biológicas na reparação de defeitos cirúrgicos em pequenos animais / Biological membranes in the repair of surgical defects in small animals

Devido à complexidade de patologias como: hérnias perianais, diafragmáticas, ressecções de grande número de costelas da parede torácica e traumatismos em traqueia, se faz necessário a utilização de membranas biológicas para auxiliar na reparação e restauração das funções normais destas regiões acometidas. O objetivo do presente trabalho é discutir algumas alternativas na reparação destas lesões com a utilização de membranas biológicas e os métodos de conservação das mesmas na clínica de pequenos animais.AU

Due to the complexity of diseases such as perianal hernias, diaphragmatic resection of a large number of ribs on the chest wall and trauma in trachea, it is necessary the use of biological membranes to assist in the repair and restoration of normal functions in those regions affected. The aim of this paper is to discuss some alternatives in the repair of these lesions with the use of biological membranes and methods of conservation of the same on the clinic of small animals.

Membranas biológicas na reparação de defeitos cirúrgicos em pequenos animais / Biological membranes in the repair of surgical defects in small animals

Devido à complexidade de patologias como: hérnias perianais, diafragmáticas, ressecções de grande número de costelas da parede torácica e traumatismos em traqueia, se faz necessário a utilização de membranas biológicas para auxiliar na reparação e restauração das funções normais destas regiões acometidas. O objetivo do presente trabalho é discutir algumas alternativas na reparação destas lesões com a utilização de membranas biológicas e os métodos de conservação das mesmas na clínica de pequenos animais.

Due to the complexity of diseases such as perianal hernias, diaphragmatic resection of a large number of ribs on the chest wall and trauma in trachea, it is necessary the use of biological membranes to assist in the repair and restoration of normal functions in those regions affected. The aim of this paper is to discuss some alternatives in the repair of these lesions with the use of biological membranes and methods of conservation of the same on the clinic of small animals.

Abdominal hernia repair with bovine pericardium seeded with mesenchymal stem cells in Wistar rats / Reparo de hérnia abdominal com pericárdio bovino associado a células-tronco mesenquimais em ratos Wistar

Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibility and strength in the reduction of abdominal hernias. Recents tissue engineering researches add mesenchymal stem cells to biological membranes with the purpose of obtaining additional cellular proliferation and consequent muscle regeneration, using biological membranes as cellular scaffolds. This article aimed to study the influence of mesenchymal stem cells in muscle regeneration in abdominal hernias, reduced with biological membranes. Materials, Methods & Results: Adult Wistar rats underwent abdominal hernia-inducing. They were divided into two groups as to the form of treatment for the reduction of hernia: stem cells associated with biological membranes or only biological membranes. After the treatment the macro and microscopic reviews were carried out in days seven, 14 and 60 postoperatively. Preparation of bovine pericardium with glycerin 98% presented efficiency in decellularization and conservation, maintaining its strength and avoiding bacterial growth. The mesenchymal stem cells obtained from bone marrow of adult Wistar rats, had capacity of proliferation. The majority of the cells was positive for the expression of surface antigens CD44, CD29 and CD99 and was negative for CD 34. In the differentiation trials, the same cells were able to differentiate into adipocytes

Vários tipos de implantes, naturais ou sintéticos, vêm sendo testados no reparo cirúrgico de hérnias. As membranas biológicas, ou arcabouços dérmicos descelularizados, apresentam reduzida formação de aderência entre o implante e as vísceras, diminuição da formação de fístulas, infecções e recorrências. Também apresentam resistência suficiente para suportar a pressão abdominal, evitando deiscências e eviscerações. [...]

Reparo de hérnia abdominal com pericárdio bovino associado a células-tronco mesenquimais em ratos Wistar / Abdominal Hernia Repair with Bovine Pericardium Seeded with Mesenchymal Stem Cells in Wistar Rats

Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibility and strength in the reduction of abdominal hernias. Recents tissue engineering researches add mesenchymal stem cells to biological membranes with the purpose of obtaining additional cellular proliferation and consequent muscle regeneration, using biological membranes as cellular scaffolds. This article aimed to study the influence of mesenchymal stem cells in muscle regeneration in abdominal hernias, reduced with biological membranes. Materials, Methods & Results: Adult Wistar rats underwent abdominal hernia-inducing. They were divided into two groups as to the form of treatment for the reduction of hernia: stem cells associated with biological membranes or only biological membranes. After the treatment the macro and microscopic reviews were carried out in days seven, 14 and 60 postoperatively. Preparation of bovine pericardium with glycerin 98% presented efficiency in decellularization and conservation, maintaining its strength and avoiding bacterial growth. The mesenchymal stem cells obtained from bone marrow of adult Wistar rats, had capacity of proliferation. The majority of the cells was positive for the expression of surface antigens CD44, CD29 and CD99 and was negative for CD 34. In the differentiation trials, the same cells were able to differentiate into adipocytes and osteocytes. With 24 h from co-cultivating adhesion of mesenchymal stem cells in the membranes was observed. There was no foreign body reaction or contamination of surgical wounds and there was intense postoperative neovascularization on seven days. All animals presented omentum adherence, but no adherence to other organs.There was no statistically difference for the different times in macroscopic assessment: deposition of fibrous tissue, implant integration. The same occurred with the microscopic evaluations between the different treatment groups. The groups of immediate and later repair presented different responses to treatment. Discussion: The use of rats as animal model was satisfactory, being suitable for surgical procedures and assessments of the abdominal cavity. The different results obtained between groups of immediate repair and late repair corroborate with the idea that there is difference between induction and repair models in the same surgery or in different surgeries with the time interval between the two, suggesting the need for methodologies that simulate the hernias chronicity. The cells used were classified as mesenchymal stem cells, because it met all the criteria of Mesenchymal and Tissue Stem Cell Committee of the International Society of Celullar Therapy. The membranes conserved with glycerin 98% demonstrated biocompatibility, because there was no rejection or necrosis, infection or exacerbated infl ammation. However the muscle regeneration was not obtained over the membranes - and the methodological difference in other latest experiments about the membranes decellularization and the co-cultivating - can leads to conclusion that the cells attached to membranes were insufficient in number to obtain the desired result. These results suggest the need of new research studies or co-cultivating times and decellularization methods of bovine pericardium for association with mesenchymal stem cells.

Abdominal hernia repair with bovine pericardium seeded with mesenchymal stem cells in Wistar rats / Reparo de hérnia abdominal com pericárdio bovino associado a células-tronco mesenquimais em ratos Wistar

Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibility and strength in the reduction of abdominal hernias. Recents tissue engineering researches add mesenchymal stem cells to biological membranes with the purpose of obtaining additional cellular proliferation and consequent muscle regeneration, using biological membranes as cellular scaffolds. This article aimed to study the influence of mesenchymal stem cells in muscle regeneration in abdominal hernias, reduced with biological membranes. Materials, Methods & Results: Adult Wistar rats underwent abdominal hernia-inducing. They were divided into two groups as to the form of treatment for the reduction of hernia: stem cells associated with biological membranes or only biological membranes. After the treatment the macro and microscopic reviews were carried out in days seven, 14 and 60 postoperatively. Preparation of bovine pericardium with glycerin 98% presented efficiency in decellularization and conservation, maintaining its strength and avoiding bacterial growth. The mesenchymal stem cells obtained from bone marrow of adult Wistar rats, had capacity of proliferation. The majority of the cells was positive for the expression of surface antigens CD44, CD29 and CD99 and was negative for CD 34. In the differentiation trials, the same cells were able to differentiate into adipocytes

Vários tipos de implantes, naturais ou sintéticos, vêm sendo testados no reparo cirúrgico de hérnias. As membranas biológicas, ou arcabouços dérmicos descelularizados, apresentam reduzida formação de aderência entre o implante e as vísceras, diminuição da formação de fístulas, infecções e recorrências. Também apresentam resistência suficiente para suportar a pressão abdominal, evitando deiscências e eviscerações. [...]

NUEVAS VÍAS DE PERMEABILIDAD Y REGULACIÓN DEL pH INTRACELULAR COMO POSIBLES BLANCOS TERAPÉUTICOS EN Plasmodium falciparum / The New Permeability Pathways And Cytosolic pH: Targets For Antimalarial Agents On Plasmodium falciparum

Actualmente, existe una necesidad sentida para el desarrollo de nuevos fármacos antimaláricos o de compuestos conocidos dirigidos contra blancos terapéuticos diferentes a los afectados por los medicamentos usuales. Son diversos los blancos que pueden ser aprovechados en Plasmodium, y la alteración de parámetros fisiológicos como el pH y el transporte de solutos pueden explicar la muerte del parásito cuando se usan compuestos antiplasmodiales, lo que representa una opción para el desarrollo de nuevas alternativas antiparasitarias. El propósito de esta revisión es por tanto, proporcionar una visión general de los efectos causados por esteroides, discutiendo el caso específico de los esteroides antiplasmodiales aislados de Solanum nudum y revisar dos procesos fisiológicos importantes en el parásito como posibles blancos terapéuticos, la modificación de permeabilidad del eritrocito infectado y el mantenimiento del pH intracelular de Plasmodium.

In malaria, attention has been posed to search or develop new antimalarial drugs or their modifications against different therapeutic targets in P. falciparum. Therapeutic targets such physiological parameters and solute transport have been proposed to kill the parasite and they represent an option for development of new drugs. We present a review on the effects of steroids, in particular the antiplasmodial steroids isolated from Solanum nudum, stressing two physiological Plasmodium processes such as the new permeability pathways on the infected red blood cells and the cytosolic pH regulation.

Avaliação histológica de membranas biológicas bovinasconservadas em glicerina e a fresco / Histological evaluation of fresh and glycerin preservedbovine biological membranes

Membranas biológicas são utilizadas em procedimentos cirúrgicos para fornecer um arcabouço e orientar o desenvolvimento de novos tecidos, mediante processos de reparação, que restabeleçam a estrutura e a função dos tecidos lesados. Assim, objetivou-se com este trabalho avaliar as características histológicas do centro tendíneo, da dura-máter, da fáscia lata, do pericárdio, do peritônio e da túnica vaginal de bovinos conservados em glicerina a 98% por período de 15, 30, 60 e 90 dias e a fresco. Para tanto, coletou-se fragmentos dessas membranas de dez bovinos mestiços, machos, com idade entre 30 e 36 meses, empregando-se técnicas de microscopia de luz convencionais. Não se observou diferenças marcantes quanto à integridade morfológica e estrutural dos elementos que constituem tanto as amostras do material a fresco quanto àqueles conservados em glicerina a 98%, que exibiram células mesoteliais e fibras conjuntivas sem alterações marcantes. Notou-se também o esmaecimento na coloração geral e maior evidenciação dos núcleos nas membranas conservadas em glicerina. Conclui-se que a glicerina é eficaz para conservação de membranas biológicas.

Biological membranes are used in surgical procedures to supply a skeleton and to guide the development of new tissues, under repairing processes, wich re-establish the structure and the function of injured tissues. So, with this study it was objectified to evaluate the histological characteristics of bovine tendinous center, dura mater, fascia lata, pericardium, peritoneum and vaginal tunic, fresh and 98% glycerin conserved for periods of 15, 30, 60 and 90 days. It was collected membranes’ fragments of ten crossbreed bovines, male, with age between 30 and 36 months, using histological conventional techniques. There was no marking differences as for the morphologic and stuctural integrity of the elements that constitutes the samples of fresh and 98% glycerin conserved material, evidencing mesothelial cells and connective tissue without intense alterations. It was still noticed a weakness in the general coloration and bigger evidenciation of the nucleous in the membranes conserved in glycerin. It can be concluded that glycerin is efficient to the conservation of biological membranes.

Implantation of two biological membranes in a corneal micropocket as an experimental model for angiogenesis / Implante de duas membranas biológicas em microbolsa corneana como modelo experimental de angiogênese

Angiogenesis has been known to participate in several physiological and pathological processes. Experimental models have been utilized to demonstrate its importance. The aim of this study was to establish an angiogenesis model using two biological membranes (pericardium and amniotic membrane) preserved in glycerin. The membranes were implanted in a micropocket in the cornea of 63 rats. The pericardium was implanted into the right cornea and the amniotic into the left cornea of the same animal. The rats were sacrificed at 1, 3, 7, 15, 30 and 60 days after the surgical procedure and the specimens underwent histology examination. Although the pericardium was more effective to induce angiogenesis and for a long period of time when compared to the amniotic membrane, both membranes can be used as an angiogenesis model.

A angiogênese participa de inúmeros processos fisiológicos e patológicos. Vários modelos experimentais são encontrados na literatura mostrando a importância de seu estudo. Estabelecemos um modelo de angiogênese utilizando duas membranas biológicas -pericárdio e membrana amniótica eqüinas conservadas em glicerina, implantadas em microbolsa em córnea de 63 ratos. Implantou-se pericárdio na córnea direita e membrana amniótica na córnea esquerda, de tal forma que pudemos analisar os resultados em um mesmo animal. As córneas dos animais foram submetidos à análise histológica aos 1, 3, 7, 15, 30 e 60 dias de pós-operatório. A angiogênese induzida pelo pericárdio xenólogo foi mais intensa e mais duradoura que a membrana amniótica xenóloga. Concluímos que ambas as membranas biológicas induziram angiogênese corneana após terem sido implantadas no interior do estroma em ratos, podendo ser utilizadas como modelo de angiogênese.