Effect of ascorbic acid and epidermal growth factor in a rat tibia defect

Purpose: Bone repair aims to restore the anatomical, biomechanical, and functional integrity of the affected structure. Here we study the effects of ascorbic acid (AA) and epidermal growth factor (EGF) applied in a single dose and in combination on the repair of a noncritical bone defect model. Methods: Twenty-four rats were divided into four groups: an intact G-1 control group, and three groups that underwent a noncritical bone defect in the right tibia: G-2 treated with AA, G-3 treated with EGF, and G-4 treated with AA in combination with EGF. After 21 days of treatment, rats were sacrificed, the tibias were dissected and a destructive biomechanical analysis of three-point flexion test was performed in a universal testing machine; the values of stiffness, resistance, maximum energy, and energy at maximum load were statistically compared. Results: G-3 and G-4 recovered the biomechanical properties of strength and stiffness of an intact tibia 3 weeks after their application. Not so the energy and energy at maximum load. For G-2, only the stiffness of an intact tibia was recovered. Conclusion: EGF and AA-EGF applied to a noncritical bone defect in the rat tibia favors the recovery of bone resistance and stiffness.

Effects of time-dependent degradation and freezing on biomechanical properties of healthy bovine jejunum / Efeitos da degradação dependente do tempo e do congelamento sobre as propriedades biomecânicas do jejuno bovino saudável

Degradation of bovine small intestine and respective effects on biomechanics have not been described to date. Biomechanical testing of intestinal tissues is often carried out within a few hours of donor death and tissue deterioration is not accounted for. Freezing is efficient for the preservation of several tissues; however, it may cause cellular damage. This study investigated the morphologic and biomechanical changes of bovine jejunum at different postmortem moments. Effects of freezing and thawing on morphology and biomechanical behavior were also examined. Macroscopic changes were first noted within eight hours of death. At this time, histologic changes also started to set in, and biomechanical tests revealed lower bursting pressure (203.10±46.14mmHg). At 12 hours, tissue rearrangement was noted, and bursting pressure increased (238.43±31.04mmHg). A second drop in pressure was detected at 18 hours (235.20±38.21mmHg), followed by a progressive drop until the end of the experimental period. Histologic changes revealed progressive deterioration. Mechanical resistance did not differ between thawed and fresh specimens. It was concluded that bovine jejunal specimens retain biomechanical resistance up to 6 hours after death. Freezing and thawing did not affect the mechanical resistance of the intestinal wall in this experimental model.

A degradação do intestino delgado de bovinos e seu efeito biomecânico não são descritos na literatura. Trabalhos que envolvem a biomecânica intestinal realizam os ensaios em poucas horas após o óbito dos doadores, sem avaliação de seu estado de deterioração. O congelamento é eficiente na conservação de vários tecidos, porém pode provocar danos em nível celular. Este estudo teve por objetivo avaliar a degradação morfológica e biomecânica do jejuno de bovinos em diferentes tempos post mortem. O efeito do congelamento e do descongelamento sobre essas características também foi avaliado. As primeiras alterações macroscópicas foram observadas oito horas após o óbito. No mesmo momento, se iniciaram as alterações histológicas e a menor pressão suportada ao teste biomecânico (203,10±46,14mmHg). A partir de 12 horas, o tecido sofreu um rearranjo, suportando maior pressão (238,43±31,04mmHg). Uma segunda queda foi detectada após 18 horas (235,20±38,21mmHg), seguida de redução progressiva até o término do experimento. As lesões histológicas foram progressivas e graduais. As amostras testadas após descongelamento não apresentaram diferença estatística quanto à resistência mecânica em comparação com os espécimes frescos. Concluiu-se que as amostras mantêm sua resistência biomecânica até 6 horas após o óbito. Também se mostrou que o congelamento e o descongelamento, nas condições testadas, não alteraram a resistência mecânica da parede intestinal.

Biomechanical comparison of a modified TPLO plate, a locking compression plate, and plate-rod constructs applied medially in a proximal gap model in canine synthetic tibias / [Comparação biomecânica entre placa de TPLO modificada, placa bloqueada e construção placa-pino intramedular aplicadas medialmente em modelo de fratura proximal em tíbias sintéticas caninas]

The aim of this study was to develop a modified tibial plateau leveling osteotomy (TPLO) plate and to compare its biomechanical properties with a locking compression plate (LCP) and plate-rod constructs for the stabilization of experimentally induced gap fractures in canine synthetic tibias. The tibial models were assigned to either repair with a modified TPLO plate (Group 1), locking compression plate construct (Group 2), or plate-rod construct (Group 3). The specimens were loaded to failure in axial compression, three-point mediolateral and craniocaudal bending. There was no statistical difference between the three groups regarding stiffness (N/mm) and deformation (mm) in axial compression. The modified TPLO plate achieved load to failure similar to the plate-rod construct in craniocaudal bending. There was no significant difference between groups on mediolateral bending tests regarding load to failure and deformation. Furthermore, there was no significant difference in stiffness between groups 1 and 2. In conclusion, the modified TPLO plate had similar mechanical properties to LCP and plate-rod construct in the axial compression and bending tests. Nonetheless, clinical studies with a large population of dogs are required to determine the value of this new implant in proximal tibial fracture repair.

Objetivou-se desenvolver uma placa de osteotomia niveladora do platô tibial (TPLO) modificada e compará-la biomecanicamente à placa de compressão bloqueada (LCP) e à construção placa-pino intramedular na estabilização da fratura cominutiva proximal em tíbias sintéticas caninas. Para tal, tíbias caninas sintéticas foram divididas em três grupos, sendo o grupo 1 formado pela placa de TPLO modificada, o grupo 2 por placas LCP e o grupo 3 pela construção placa-pino intramedular. Os espécimes foram submetidos à carga até a falha em compressão axial, flexão mediolateral e craniocaudal em três pontos. Não houve diferença estatística entre os três grupos quanto à rigidez (N/mm) e à deformação (mm) nos testes de compressão axial. A placa de TPLO modificada obteve carga até a falha semelhante à construção placa-pino intramedular em flexão craniocaudal. Não houve diferença significativa entre os grupos nos testes de flexão mediolateral em relação à carga até a falha e a deformação, e a variável rigidez não apresentou diferenças significativas entre os grupos 1 e 2. Em conclusão, a placa de TPLO modificada apresentou similaridade mecânica em comparação com a LCP e a construção placa-pino. No entanto, estudos clínicos são necessários para determinar o valor desse novo implante na fixação de fraturas tibiais proximais.

Effect of glycerol addition time on the cryopreserved Korean native brindle cattle (Chikso) sperm quality

Although cryopreservation is an efficient method for maintaining the biological and genetic resources of sperm, the sperm damage during the cryopreservation process cannot be ignored. It should be possible to obtain the most effective cryopreservation performance by accurately grasping the effects of various factors on the cryopreservation of sperm. The previous study demonstrated that a suitable standard protocol for cryopreservation of Korean native brindled cattle (Chikso) does not exist, based on the methods for semen cryopreservation of Chikso differ in each research center. The most obvious difference between most of protocols is the addition of glycerol before and after cooling during the Chikso cryopreserved semen process. Therefore we focused on the effects of glycerol addition time on the quality of cryopreserved Chikso sperm. In the present study, 27 individual Chikso samples were collected by transrectal massage and divided into two parts: the "cryopreservation method A" group (adding glycerol before cooling) and the "cryopreservation method B" group (adding glycerol after cooling). Meanwhile, the values of various sperm parameters were derived from each group, including sperm motility, kinematics, capacitation status, cell viability, and intracellular ATP levels, which we used to compare and evaluate sperm function. The results of this study indicated that during the semen cryopreservation process of the Chikso, the addition of glycerol after cooling yielded superior results in a variety of sperm parameters, such as sperm motility, progressive motility, rapid motility, VCL, VSL, VAP, ALH, capacitation status, viability, and intracellular ATP level after freezing and thawing. Our study is suggested that the glycerol addition time during the cryopreservation process for Chikso should be considered. In addition, our results may be provided reference to develop suitable the cryopreservation procedure of the Chikso sperm.(AU)

Ex vivo biomechanical testing of Funkquist B dorsal laminectomy between the sixth and seventh cervical vertebrae in dogs / Análise biomecânica ex vivo dos efeitos da laminectomia dorsal Funkquist B entre a sexta e a sétima vertebras cervicais em cães

Dorsal laminectomy is routinely performed for spinal cord compressions or stenosis of the cervical vertebral canal. However, despite good results, relevant complications have been described in dogs. Considering the incomplete understanding of the necessity for complementary surgical stabilization after performing laminectomies in the cervical region, this study compared the resistance and range of motion (ROM) of the cervical spinal column subjected to Funkquist B laminectomy between the sixth and seventh vertebrae in dogs. Forty-four cervical vertebral columns (C2-T1) of dogs, with an average weight of 26.2±3.8 kg, were selected using radiography and computed tomography. Four experimental groups (n=11) were established according to the mechanical test: two control groups (flexion and extension control) and two laminectomy groups (flexion and extension laminectomies). Numerical results of the maximum load for measuring the resistance and ROM of the columns of the two control groups and the two laminectomy groups were compared. The laminectomy groups showed a lower maximum load, regardless of the mechanical test performed (P<0.001). The ROM was not influenced by laminectomy, the type of mechanical test (ventral flexion or extension), or its interaction (P<0.05). There was no interaction between the effect of the laminectomy factors (yes or no) and the effect of the mechanical tests for ventral flexion or extension (P<0.05). In conclusion, Funkquist B dorsal cervical laminectomy between C6 and C7 decreases mechanical resistance with a supraphysiological loading force but does not alter the ROM, suggesting that it can be used without additional mechanical stabilization in dogs.

A laminectomia dorsal é realizada com frequência no tratamento de compressões medulares ou estenose do canal vertebral cervical. No entanto, complicações relevantes têm sido descritas em cães. Considerando que ainda não há entendimento completo da necessidade de estabilização cirúrgica complementar após a realização de uma ou múltiplas laminectomias na região cervical, o objetivo deste estudo foi comparar a resistência e amplitude de movimento (ADM) da coluna cervical submetida à laminectomia Funkquist B entre a sexta e a sétima vértebras em cães. Quarenta e quatro colunas vertebrais cervicais (C2-T1) de cães, com peso médio de 26,2 ± 3,8 kg, foram selecionadas por meio de radiografia e tomografia computadorizada. Quatro grupos experimentais (n = 11) foram estabelecidos de acordo com o teste mecânico realizado: dois grupos controle (flexão e extensão controle) e dois grupos laminectomia (flexão e extensão laminectomia). Os resultados numéricos da carga máxima para medir a resistência e ADM das colunas dos dois grupos de controle e dos dois grupos de laminectomia foram comparados. Os grupos de laminectomia apresentaram menores valores de carga máxima, independentemente do teste mecânico realizado (P < 0,001). A ADM não foi influenciada pela laminectomia, tipo de teste mecânico (flexão ou extensão ventral) ou sua interação (P < 0,05). Não houve interação entre o efeito do fator de laminectomia, sim ou não, ou o efeito do teste mecânico na flexão ou extensão ventral (P < 0,05). A laminectomia cervical dorsal Funkquist B entre C6 e C7 diminui a resistência mecânica com uma força de carga suprafisiológica, mas não altera a ADM, sugerindo que pode ser usada sem estabilização mecânica adicional em cães.

Aspectos da locomoção e bases gerais dos andamentos básicos naturais dos equinos / Aspects of locomotion and general bases of basic natural gait of horses / Aspectos de locomoción y bases generales de la marcha natural básica en caballos

A locomoção é a função do organismo que permite executar os movimentos corporais e o deslocamento do centro de gravidade em qualquer direção. Os andamentos são considerados formas de locomoção, que podem ser habilidades inatas ou adquiridas, e se classificam em naturais ou artificiais e em básicos ou especiais. Os básicos naturais são o passo, a andadura, o trote e o galope de três e quatro tempos. Entre os andamentos naturais especiais estão as marchas, como a picada e a batida, presentes em algumas raças de equinos brasileiras, e as modalidades de "paso" ocorrentes nos cavalos passo fino Peruano, fino Colombiano e fino de Porto Rico. Nos andamentos os equinos movimentam os membros locomotores, deslocam o corpo com características como a velocidade, sequência dos momentos de apoio e elevação, além de mostrar as pegadas, as pistas e as batidas, que são características biomecânicas que definem os andamentos. O estudo dos andamentos é parte vinculante da biomecânica/cinesiologia e, portanto, deve ser compreendido além da anatomia funcional ou da fisiologia, da medicina esportiva e do estudo das claudicações. Esta revisão tem por objetivo revisar e descrever os conceitos gerais da locomoção e os diferentes andamentos naturais em equinos.(AU)

Locomotion is the function of the organism that allows the execution of body movements and displacement of the center of gravity in any direction. Gaitsare the forms of locomotion that can be innate or acquired skills, classified as natural or artificial and as basic or special. The natural basic gaits are the walk, pace, trot and three-and four-beat gallop. Among the special natural gaits are the gaits, such as the "marcha batida" and "marcha picada", observed in some Brazilian horse breeds, and the "paso" modalities that occur in Peruvian fine, Colombian fine and Puerto Rican fine horses. In the gaits, the horses move the limbs, move the body with characteristics such as speed, sequence of moments of bearing and elevation, and show the footprints, tracks and beats, which are biomechanical characteristics of the gaits. The study of gaits is a complementary part of biomechanics/kinesiology and must be understood beyond functional anatomy or physiology, sports medicine and the study of lameness. This literature review aims to describe the general concepts of locomotion and the different natural gaits in horses.(AU)

La locomoción es la función del organismo que permite la ejecución de movimientos corporales y el desplazamiento del centro de gravedad en cualquier direcciónde un entorno. Los modos de andar se consideran formas de locomoción que pueden ser habilidades innatas o adquiridas, clasificadas en naturales o artificiales y en básicas o especiales. Los fundamentos naturales son el paso, la ambladura, el trote, el galope de tres y cuatro tiempos. Entre los aires naturales especiales están los aires, como las "marchas batida" y "marcha picada", presentes en las razas de caballos brasileños, y las modalidades de "paso" que se dan en los caballos finos peruanos, finos colombianos y finos puertorriqueños. En las marchas, los caballos mueven las extremidades locomotoras, mueven el cuerpo con características como velocidad, secuencia de momentos de apoyo y elevación, además de mostrar las pisadas, huellas y golpes, que son características biomecánicas que definen las marchas. El estudio de revision de la marcha es una parte vinculante de la biomecánica/kinesiología y, por lo tanto, debe entenderse más allá de la anatomía o fisiología funcional, la medicina deportiva y el estudio de la cojera, siendo estos partes de la "ciencia equina". Este material tiene como objetivo revisar y describir los conceptos generales de locomoción y los diferentes aires naturales en los caballos.(AU)

Biomechanical evaluation of a new femoral stem design for total hip replacement in a canine model

ABSTRACT Purpose To evaluate the biomechanical properties of a novel total hip replacement femoral stem. Methods Eight pairs of femurs from dog cadavers were used. The femurs were separated into different groups. A novel femoral stem with a convex proximal portion (Stem B) was biomechanically evaluated and compared to awell-known veterinary collared stem (Stem A). Femoral stems were inserted into the contralateral femurs from the same dog, forming 16 constructs. A flexo-compression load was applied on the axial axis of each sample. Maximum strength, deflection, stiffness, and energy absorption were analysed. Results Group B constructs showed significantly higher values (p ? 0.05) for the variables, except stiffness. The mean maximum strength was 1,347 ± 357 N for Group A and 1,805 ± 123 N for Group B (p ? 0.0069). The mean deflection was5.54 ± 2.63 mm for Group A and 10.03 ± 3.99 mm for Group B (p ? 0.0056). For the energy variable, the force was 6,203 ± 3,488 N/mm for Group A and 12,885 ± 5,056 N/mm for Group B (p ? 0.0054). Stem B had greater maximum strength, deflection, and energy. Conclusions The new stem was effective in neutralizing the impact of axial flexion-compression stresses during biomechanical tests in cadaveric models.

Two-dimensional and three-dimensional techniques for determining the kinematic patterns for hindlimb obstacle avoidance during sheep locomotion / Técnicas bidimensionais e tridimensionais para determinar os padrões cinemáticos durante a ultrapassagem de obstáculos pelos membros pélvicosdurante a locomoção de ovinos

Analysis of locomotion is often used as a measure for impairment and recovery following experimental peripheral nerve injury. Compared to rodents, sheep offer several advantages for studying peripheral nerve regeneration. In the present study, we compared for the first time, two-dimensional (2D) and three-dimensional (3D) hindlimb kinematics during obstacle avoidance in the ovine model. This study obtained kinematic data to serve as a template for an objective assessment of the ankle joint motion in future studies of common peroneal nerve (CP) injury and repair in the ovine model. The strategy used by the sheep to bring the hindlimb over a moderately high obstacle, set to 10% of its hindlimb length, was pronounced knee, ankle and metatarsophalangeal flexion when approaching and clearing the obstacle. Despite the overall time course kinematic patterns about the hip, knee, ankle, and metatarsophalangeal were identical, we found significant differences between values of the 2D and 3D joint angular motion. Our results showed that the most apparent changes that occurred during the gait cycle were for the ankle (2D-measured STANCEmax: 157±2.4 degrees vs. 3D-measured STANCEmax: 151±1.2 degrees; P .05) and metatarsophalangeal joints (2D-measured STANCEmin: 151±2.2 degrees vs. 3D-measured STANCEmin: 162 ± 2.2 degrees; P .01 and 2D-measured TO: 163±4.9 degrees vs. 3D-measured TO: 177±1.4 degrees; P .05), whereas the hip and knee joints were much less affected. Data and techniques described here are useful for an objective assessment of altered gait after CP injury and repairin an ovine model.(AU)

A análise da locomoção é frequentemente usada como uma medida para avaliar a disfunção e sua recuperação após lesão nervosa periférica experimental. Quando comparadas com os roedores, as ovelhas oferecem várias características atrativas como modelo experimental para o estudo da regeneração nervosa periférica. Não existem estudos acerca dos resultados da locomoção após lesão e reparação do nervo periférico no modelo ovino. No presente estudo, realizámos e comparámos a cinemática bidimensional (2D) e, pela primeira vez, tridimensional (3D) do membro pélvico durante a ultrapassagem de obstáculos no modelo ovino. Este estudo teve como objetivo obter dados cinemáticos para servir de modelo para uma avaliação objetiva do movimento articular do tornozelo em estudos futuros de lesão e reparação do nervo fibular comum (FC) no modelo ovino. A estratégia usada pelas ovelhas para elevar o membro pélvico sobre um obstáculo com uma altura moderada, fixado em 10% do seu comprimento, caracteriza-se por uma flexão pronunciada do joelho, tornozelo e metatarso-falangeana ao se aproximar e ultrapassar o obstáculo. Apesar dos padrões cinemáticos do quadril, joelho, tornozelo e metatarso-falangeano terem sido idênticos, foram encontradas diferenças significativas entre os valores do movimento angular das articulações em 2D e 3D. Os nossos resultados mostram que as mudanças mais aparentes que ocorreram durante o ciclo da marcha foram nas articulações do tornozelo (em 2DSTANCEmax: 157±2.4 graus vs. em 3D STANCEmax: 151±1.2 graus; P .05) e metatarso-falangeana (em 2D STANCEmin: 151±2.2 graus vs. em 3D STANCEmin: 162 ± 2.2 graus; P .01 e em 2D TO: 163±4.9 graus vs. em 3D TO: 177±1.4 graus; P .05), enquanto as articulações do quadril e do joelho foram muito menos afetadas. É provável que os dados e técnicas descritas aqui sejam úteis para uma avaliação objetiva das alterações na marcha após lesão e reparação do PC no modelo ovino.(AU)

A castor oil plant (Ricinus communis)-derived implant improves the biomechanical properties of noncritical bone defects

Purpose The biomechanical properties of the polyurethanes implant material derived from castor oil plant (Ricinus communis) were evaluated in a noncritical bone defect model in rat tibia. Methods After three weeks of the implant application, the tibias were tested by means of the biomechanical three-point flexion test and resistance, rigidity, energy at maximum load and maximum energy were evaluated. Nonparametric statistical analysis was performed. Results It was found that the group that received the implant behaved the same as the intact control group and also showed a significant increase in maximum load compared to the spontaneous repair group. Conclusions Our results indicate that the tibias with the implant material in a noncritical bone defect recover normal biomechanical parameters in less time than spontaneously.(AU)

Ex-vivo evaluation of the three-column concept in canine thoracolumbar fractures / [Avaliação em ex-vivo do conceito dos três compartimentos em fraturas toracolombares da coluna]

Traumatic events such as a motor vehicle accident or falling from heights are very common in veterinary medicine and often lead to vertebral fracture-luxation with concomitant spinal cord injuries, mostly in the thoracolumbar spine. The purpose of this cadaveric biomechanical study was to determine the feasibility of the three-column concept in canine thoracolumbar segments with induced fractures. Eighteen Functional Spinal Units (FSU) of the thoracolumbar segments (T12-L2) were collected from 18 medium-sized adult dog cadavers and were subjected to flexion-extension and lateral bending tests so that range of motion (ROM) was recorded with a goniometer. Fractures were induced by compressive loads applied by a universal testing machine (EMIC®). After this, specimens were screened using computed tomography (CT) and the fractures were graded as affecting one, two or three columns, and divided into groups A, B, and C, respectively. Post-fracture range of motion (ROM) was compared with the previous results. Groups B and C (with fractures in two or three columns) had instability in the two axes evaluated (P<0.05). The outcomes of this study support the applicability of the three-column theory to thoracolumbar spines of dogs, as the FSUs that suffered fractures in two or more columns showed axial instability.(AU)

Eventos traumáticos, como acidentes automobilísticos ou quedas, são muito comuns na medicina veterinária e, frequentemente, levam a fraturas ou luxações vertebrais, associadas a lesões medulares concomitantes, mais frequentemente na coluna toracolombar. O propósito deste estudo biomecânico em cadáveres foi determinar a viabilidade da teoria dos três compartimentos em fraturas induzidas em segmentos toracolombares de cães. Dezoito unidades espinhais funcionais (UEF) de segmentos toracolombares (T12-L2) foram coletadas de 18 cadáveres de cães adultos de médio porte e submetidas a testes de flexão-extensão e curvamento lateral, de modo que a amplitude de movimento (ADM) foi registrada com um goniômetro. Fraturas foram induzidas por meio de cargas compressivas aplicadas por uma máquina universal de ensaios (EMIC®). As amostras foram submetidas à tomografia computadorizada (TC), e as fraturas foram classificadas como afetando um, dois ou três compartimentos e divididas nos grupos A, B e C, respectivamente. A ADM pós-fratura foi comparada com os resultados prévios. Os grupos B e C (com fraturas em dois ou três compartimentos) apresentaram instabilidade nos dois eixos avaliados (P<0,05). Os resultados deste estudo corroboram a aplicabilidade da teoria dos três compartimentos para segmentos de coluna toracolombar em cães, uma vez que as UEF que sofreram as fraturas em dois ou mais compartimentos apresentaram instabilidade axial.(AU)

Ex-vivo evaluation of the three-column concept in canine thoracolumbar fractures / [Avaliação em ex-vivo do conceito dos três compartimentos em fraturas toracolombares da coluna]

Traumatic events such as a motor vehicle accident or falling from heights are very common in veterinary medicine and often lead to vertebral fracture-luxation with concomitant spinal cord injuries, mostly in the thoracolumbar spine. The purpose of this cadaveric biomechanical study was to determine the feasibility of the three-column concept in canine thoracolumbar segments with induced fractures. Eighteen Functional Spinal Units (FSU) of the thoracolumbar segments (T12-L2) were collected from 18 medium-sized adult dog cadavers and were subjected to flexion-extension and lateral bending tests so that range of motion (ROM) was recorded with a goniometer. Fractures were induced by compressive loads applied by a universal testing machine (EMIC®). After this, specimens were screened using computed tomography (CT) and the fractures were graded as affecting one, two or three columns, and divided into groups A, B, and C, respectively. Post-fracture range of motion (ROM) was compared with the previous results. Groups B and C (with fractures in two or three columns) had instability in the two axes evaluated (P<0.05). The outcomes of this study support the applicability of the three-column theory to thoracolumbar spines of dogs, as the FSUs that suffered fractures in two or more columns showed axial instability.(AU)

Eventos traumáticos, como acidentes automobilísticos ou quedas, são muito comuns na medicina veterinária e, frequentemente, levam a fraturas ou luxações vertebrais, associadas a lesões medulares concomitantes, mais frequentemente na coluna toracolombar. O propósito deste estudo biomecânico em cadáveres foi determinar a viabilidade da teoria dos três compartimentos em fraturas induzidas em segmentos toracolombares de cães. Dezoito unidades espinhais funcionais (UEF) de segmentos toracolombares (T12-L2) foram coletadas de 18 cadáveres de cães adultos de médio porte e submetidas a testes de flexão-extensão e curvamento lateral, de modo que a amplitude de movimento (ADM) foi registrada com um goniômetro. Fraturas foram induzidas por meio de cargas compressivas aplicadas por uma máquina universal de ensaios (EMIC®). As amostras foram submetidas à tomografia computadorizada (TC), e as fraturas foram classificadas como afetando um, dois ou três compartimentos e divididas nos grupos A, B e C, respectivamente. A ADM pós-fratura foi comparada com os resultados prévios. Os grupos B e C (com fraturas em dois ou três compartimentos) apresentaram instabilidade nos dois eixos avaliados (P<0,05). Os resultados deste estudo corroboram a aplicabilidade da teoria dos três compartimentos para segmentos de coluna toracolombar em cães, uma vez que as UEF que sofreram as fraturas em dois ou mais compartimentos apresentaram instabilidade axial.(AU)

Comparison of Some Biomechanical Properties of Tibiotarsus in Four Different Feather Color Lines of 60-Day Old Female Quails

This study aimed to compare some morphological and mechanical measurements of four different color female quails to contribute to the formation of the morphological database. Quails are the smallest farmed avian species which are becoming more important for the poultry industry. They are also used as experimental animals and are valuable birds for researches. Genetic factors are important determinants of bone strength. Thus, skeletal disorders may be reduced by breeding selection in quails. Forty female quails with four different feather colors, including wild, white, yellow, and black, were compared at 60 days of age. Each quail group contained ten individuals. A three-point bending test was performed with a custom-made testing machine designed for low strength materials. No significant difference was found between the groups in terms of body weight. The tibiotarsus weight in wild and black (0,665±0,055g and 0,687±0,025g, respectively) was significantly lower than in the others but, the significant highest value was in white quails (0,758±0,063g) (p=0.001). Significantly shorter tibiotarsus was observed in the black quails (51,286±1,374mm), while the tibiotarsi of the white and yellow quails were the tallest (53,216±1,796mm and 53,083±1,092mm, respectively) (p=0.005). There were no significant differences among the groups in the biomechanical properties of tibiotarsus, except stiffness. Stiffness was the highest in the white quails (109,500±3,807 N/mm) and the lowest in the black quails (99,000±9,498 N/mm) (p=0.042). In conclusion, white quails have been observed to have relatively better bone biomechanical properties compared to the other color groups at 60 days of age.(AU)

Tensiometric evaluation of the effect of low frequency electric stimulation on healing Achilles tendons in rats

Purpose: To evaluate the effects of low-frequency electric stimulation on biomechanics following surgical treatment of the Achilles tendon in rats. Methods: Forty-two rats were divided into two groups. One was given electric stimulation and the other was not. All were submitted to Achilles tenotomy and tenorrhaphy performed with a modified Kessler stitch. The experiment group underwent electric stimulation with 2 Hz, a nonpolarized current of 1 mA intensity for 14 days. The animals were euthanized at 2, 4 and 6 weeks for the biomechanical study. Results: The work performed, that is, the tendons capacity to absorb energy until rupture, was greater in the electrically stimulated group in the 2nd (p = 0.032) and in the 6th week (p = 0.010). The maximum tension, which is the capacity to support a load, was higher in the treated group in the 2nd (p = 0.030) and the 6th week (p = 024). These results indicate greater resistance of the electrically stimulated tendons. An analysis of the elastic module showed no differences. Conclusion: Low-frequency electric stimulation increased the resistance of the tendons at 2 and 6 weeks of evolution in rats.(AU)

Comparison of Some Biomechanical Properties of Tibiotarsus in Four Different Feather Color Lines of 60-Day Old Female Quails

This study aimed to compare some morphological and mechanical measurements of four different color female quails to contribute to the formation of the morphological database. Quails are the smallest farmed avian species which are becoming more important for the poultry industry. They are also used as experimental animals and are valuable birds for researches. Genetic factors are important determinants of bone strength. Thus, skeletal disorders may be reduced by breeding selection in quails. Forty female quails with four different feather colors, including wild, white, yellow, and black, were compared at 60 days of age. Each quail group contained ten individuals. A three-point bending test was performed with a custom-made testing machine designed for low strength materials. No significant difference was found between the groups in terms of body weight. The tibiotarsus weight in wild and black (0,665±0,055g and 0,687±0,025g, respectively) was significantly lower than in the others but, the significant highest value was in white quails (0,758±0,063g) (p=0.001). Significantly shorter tibiotarsus was observed in the black quails (51,286±1,374mm), while the tibiotarsi of the white and yellow quails were the tallest (53,216±1,796mm and 53,083±1,092mm, respectively) (p=0.005). There were no significant differences among the groups in the biomechanical properties of tibiotarsus, except stiffness. Stiffness was the highest in the white quails (109,500±3,807 N/mm) and the lowest in the black quails (99,000±9,498 N/mm) (p=0.042). In conclusion, white quails have been observed to have relatively better bone biomechanical properties compared to the other color groups at 60 days of age.

Análise da resistência de placas ósseas de acrílico fabricadas a laser quando submetidas a diferentes forças que agem sobre o foco de fratura / Analysis of the resistance of laser-made acrylic bone plates when subjected to different forces acting on the fracture focus

Objetivou-se com este trabalho analisar a resistência de placas ósseas de acrílico, confeccionadas com cortadora a laser CO2, quando submetidas às forças que agem sobre o foco de fratura. Foram utilizados 40 fêmures de ovinos (Ovis aries) e confeccionadas 40 placas de acrílico, os quais foram avaliados em grupos: grupo OP - foram avaliados 20 ossos fraturados reduzidos com 20 placas de acrílico; grupo PS - foram avaliadas 20 placas de acrílico; e grupo OS - foram avaliados 20 ossos íntegros e frescos. Todos foram submetidos a ensaios mecânicos de compressão, flexão, torção e tração, em máquina de ensaios universal EMIC® 10000. Os testes eram interrompidos quando havia fratura do corpo de prova. O grupo PS suportou carga de compressão significativamente superior aos demais grupos OP e OS (13.255±290N, 4.932±827N e 8.681±303N, respectivamente). Já em relação à prova de flexão, o grupo OS foi significativamente mais resistente, com média de 2.698±305N, em relação aos grupos OP e PS, que obtiveram 1.315±92N e 1.537±37N, respectivamente. Conclui-se que as placas de acrílico usinadas a laser apresentam resistência mecânica inferior ao fêmur de ovinos, entretanto, devido à resistência exibida nos testes, demonstraram potencial para serem implantadas em ossos com menor demanda de carga.(AU)

The objective of this work was to analyze the resistance of acrylic bone plates, made with CO 2 laser cutter, when subjected to the forces acting on the fracture focus. Forty ovine femurs (Ovis aries) were used and 40 acrylic plates were prepared and evaluated in groups: In the OP Group, 20 fractured bones reduced with 20 acrylic plates were evaluated; in the PS Group, 20 acrylic plates were evaluated; and in the OS Group 20 intact and fresh bones were evaluated. All were submitted to mechanical tests of compression, bending, twisting and traction in an EMIC® 10000 universal testing machine. The tests were interrupted when the body of proof was fractured. The PS group supported a significantly higher compression load than the other OP and OS groups (13,255±290 N, 4,932±827 N and 8,681±303 N, respectively). Regarding the flexural test, the OS group was significantly more resistant, with a mean of 2,698±305 N, compared to the groups OP and PS that obtained 1,315±92 N and 1,537±37 N respectively. It is concluded that the laser-machined acrylic plates have inferior mechanical resistance to the femur of the ovine, however, due to the presented resistance, it shows potential to be implanted in bones with lower load demand.(AU)

Análise da resistência de placas ósseas de acrílico fabricadas a laser quando submetidas a diferentes forças que agem sobre o foco de fratura / Analysis of the resistance of laser-made acrylic bone plates when subjected to different forces acting on the fracture focus

Objetivou-se com este trabalho analisar a resistência de placas ósseas de acrílico, confeccionadas com cortadora a laser CO2, quando submetidas às forças que agem sobre o foco de fratura. Foram utilizados 40 fêmures de ovinos (Ovis aries) e confeccionadas 40 placas de acrílico, os quais foram avaliados em grupos: grupo OP - foram avaliados 20 ossos fraturados reduzidos com 20 placas de acrílico; grupo PS - foram avaliadas 20 placas de acrílico; e grupo OS - foram avaliados 20 ossos íntegros e frescos. Todos foram submetidos a ensaios mecânicos de compressão, flexão, torção e tração, em máquina de ensaios universal EMIC® 10000. Os testes eram interrompidos quando havia fratura do corpo de prova. O grupo PS suportou carga de compressão significativamente superior aos demais grupos OP e OS (13.255±290N, 4.932±827N e 8.681±303N, respectivamente). Já em relação à prova de flexão, o grupo OS foi significativamente mais resistente, com média de 2.698±305N, em relação aos grupos OP e PS, que obtiveram 1.315±92N e 1.537±37N, respectivamente. Conclui-se que as placas de acrílico usinadas a laser apresentam resistência mecânica inferior ao fêmur de ovinos, entretanto, devido à resistência exibida nos testes, demonstraram potencial para serem implantadas em ossos com menor demanda de carga.(AU)

The objective of this work was to analyze the resistance of acrylic bone plates, made with CO 2 laser cutter, when subjected to the forces acting on the fracture focus. Forty ovine femurs (Ovis aries) were used and 40 acrylic plates were prepared and evaluated in groups: In the OP Group, 20 fractured bones reduced with 20 acrylic plates were evaluated; in the PS Group, 20 acrylic plates were evaluated; and in the OS Group 20 intact and fresh bones were evaluated. All were submitted to mechanical tests of compression, bending, twisting and traction in an EMIC® 10000 universal testing machine. The tests were interrupted when the body of proof was fractured. The PS group supported a significantly higher compression load than the other OP and OS groups (13,255±290 N, 4,932±827 N and 8,681±303 N, respectively). Regarding the flexural test, the OS group was significantly more resistant, with a mean of 2,698±305 N, compared to the groups OP and PS that obtained 1,315±92 N and 1,537±37 N respectively. It is concluded that the laser-machined acrylic plates have inferior mechanical resistance to the femur of the ovine, however, due to the presented resistance, it shows potential to be implanted in bones with lower load demand.(AU)

Mineral composition, histomorphometry, and bone biomechanical properties are improved with probiotic, prebiotic, and symbiotic supplementation in rats chronically exposed to passive smoking: a randomized pre-clinical study / Composição mineral, histomorfometria e propriedades biomecânicas óssea são melhoradas com a suplementação de probióticos, prebióticos e simbióticos em ratos expostos cronicamente ao tabagismo passivo: estudo pré-clínico randomizado

Cigarette smoke in large centers is one of the most important causes of chronic inflammatory diseases in public health and is associated with a decrease in bone mass, consolidation process, and bone remodeling. Due to their ability to improve intestinal absorption and compete with pathogenic microorganisms, dietary supplementation with functional foods may contribute to improvement in bone quality. Therefore, the objective of this study was to evaluate the effects of functional, probiotic, prebiotic, or symbiotic food supplementation on mineral composition, histomorphometry, and bone biomechanical properties of rats in the growth phase, chronically exposed to cigarette smoke (T).Sixty-four young male rats were randomly assigned to eight groups (n=8): control (C) [standard diet (SD)]; probiotic (Pro) [SD + probiotic (Lactobacillus acidophilus, Enterococcus faecium, Bifidobacterium thermophilum and Bifidobacterium longum) (2-5 109 UFC each)]; prebiotic (Pre) [SD+ prebiotic (mannan oligosaccharide)]; symbiotic (Sym) (SD + probiotic + prebiotic); control smoking (SC) [(SD + exposure protocol to passive smoking (PS)]; probiotic smoking (ProS) (SD + probiotic + PS); prebiotic smoking (PreS) (SD + prebiotic + PS), and symbiotic smoking (SymS)(SD + prebiotic + probiotic + PS). The animals were euthanized after 189 days of the experimental protocol. Results showed that supplementation with probiotics, prebiotics, and symbiotics significantly improved (P<0.05) the parameters: P, Ca, Mg, BMD, BMC, strength, resilience, and size of area of the femoral diaphysis of the animals chronically exposed or not cigarette smoke. We concluded that functional food supplementation improved the bone health of rats chronically exposed or not to cigarette smoke.(AU)

A fumaça de cigarro em grandes centros é uma das causas mais importantes de doenças inflamatórias crônicas em saúde pública e esta associada à diminuição de massa óssea, processo de consolidação e remodelação óssea. Os alimentos funcionais suplementados na dieta, devido sua capacidade de melhorar a absorção intestinal e competir com microrganismos patógenos, podem contribuir para a melhora da qualidade óssea. Portanto, o objetivo desse estudo foi avaliar os efeitos da suplementação de alimentos funcionais, probiótico, prebiótico ou simbiótico, na composição mineral, histomorfometria e nas propriedades biomecânicas ósseas de ratos em fase de crescimento expostos cronicamente a fumaça do cigarro (T). Sessenta e quatro ratos machos jovens foram randomicamente distribuídos em oito grupos (n=8): controle (C) [dieta basal (DB)]; probiótico (Pro) [DB + probiótico (Lactobacillus acidophilus, Enterecoccusfaecium, Bifidobacterium thermophilumandBifidobacterium longum (2-5 109 UFC cada)]; prebiótico (Pre) [DB + prebiótico (mananoligossacarídeo)]; simbiótico (Sym) (DB + probiótico + prebiótico); controle fumante (CS) [(DB + protocolo de exposição ao tabagismo passivo(PT)]; probiótico fumante (ProS) (DB + probiótico + PT); prebiótico fumante (PreS) (DB + prebiótico + PT); e simbiótico fumante (SymS) (DB + prebiótico + probiótico + PT). Os animais foram mortos após 189 dias de período experimental.Os resultados revelaram que a suplementação com probióticos, prebióticos e simbióticos melhoraram significativamente (P<0,05) os parâmetros: P, Ca, Mg, DMO, CMO, resistência, resiliência e tamanho da área das diáfises dos fêmures dos animais expostos, cronicamente ou não, a fumaça do cigarro. Os resultados permitem concluir que a suplementação dos alimentos funcionais melhorou a saúde óssea de ratos expostos cronicamente ou não a fumaça do cigarro.(AU)

Biomechanical analysis of the masticatory movement before and after adjusting dental occlusion in equine / Análise biomecânica do movimento mastigatório antes e depois do ajuste oclusal dental em equinos

The aim of this study was to evaluate through three-dimensional kinematic analysis the influence of occlusal adjustment by tooth wear in masticatory biomechanics of horses. Seven clinically healthy thoroughbred Arabian horses with strong occlusal irregularities were used, of which seven castrated males and one female of between seven and nineteen years of age. Three digital video cameras and seven spherical reflective markers placed on the horses' face were employed. The animals were filmed twice in succession: while chewing hay before and after the occlusal adjustment by tooth wear. Following that, kinematic analysis was made of the movements obtained by means of the images which were synchronized, segmented and reconstructed three-dimensionally with the help of Dvideow program. Mathematical functions were applied in Matlab environment for obtaining the values of the amplitudes of movements. The results of the biomechanical analysis showed that the occlusal adjustment increases the range of mandibular movements in horses.(AU)

O objetivo deste estudo foi avaliar, através de análise cinemática tridimensional, a influência do ajuste oclusal por desgaste dentário na biomecânica da mastigação de equinos. Foram utilizados sete cavalos puro sangue árabe, clinicamente saudáveis, com irregularidades oclusais relevantes, sendo seis machos castrados e uma fêmea, de sete a dezenove anos de idade. Três câmeras de vídeo digitais e sete marcadores reflexivos esféricos foram colocados na face dos equinos. Os animais foram filmados duas vezes seguidas: durante a mastigação do feno antes e após o ajuste oclusal por desgaste dental. Na sequência, procedeu-se a cinemática dos movimentos obtidos por meio das imagens sincronizadas, segmentadas e reconstruídas em três dimensões, com a ajuda do programa Dvideow. Funções matemáticas foram aplicadas no ambiente Matlab para a obtenção dos valores de amplitudes dos movimentos. Os resultados da análise biomecânica mostraram que o ajuste oclusal aumenta a gama de movimentos mandibulares em equinos.(AU)

Biomechanical analysis of the masticatory movement before and after adjusting dental occlusion in equine / Análise biomecânica do movimento mastigatório antes e depois do ajuste oclusal dental em equinos

The aim of this study was to evaluate through three-dimensional kinematic analysis the influence of occlusal adjustment by tooth wear in masticatory biomechanics of horses. Seven clinically healthy thoroughbred Arabian horses with strong occlusal irregularities were used, of which seven castrated males and one female of between seven and nineteen years of age. Three digital video cameras and seven spherical reflective markers placed on the horses' face were employed. The animals were filmed twice in succession: while chewing hay before and after the occlusal adjustment by tooth wear. Following that, kinematic analysis was made of the movements obtained by means of the images which were synchronized, segmented and reconstructed three-dimensionally with the help of Dvideow program. Mathematical functions were applied in Matlab environment for obtaining the values of the amplitudes of movements. The results of the biomechanical analysis showed that the occlusal adjustment increases the range of mandibular movements in horses.(AU)

O objetivo deste estudo foi avaliar, através de análise cinemática tridimensional, a influência do ajuste oclusal por desgaste dentário na biomecânica da mastigação de equinos. Foram utilizados sete cavalos puro sangue árabe, clinicamente saudáveis, com irregularidades oclusais relevantes, sendo seis machos castrados e uma fêmea, de sete a dezenove anos de idade. Três câmeras de vídeo digitais e sete marcadores reflexivos esféricos foram colocados na face dos equinos. Os animais foram filmados duas vezes seguidas: durante a mastigação do feno antes e após o ajuste oclusal por desgaste dental. Na sequência, procedeu-se a cinemática dos movimentos obtidos por meio das imagens sincronizadas, segmentadas e reconstruídas em três dimensões, com a ajuda do programa Dvideow. Funções matemáticas foram aplicadas no ambiente Matlab para a obtenção dos valores de amplitudes dos movimentos. Os resultados da análise biomecânica mostraram que o ajuste oclusal aumenta a gama de movimentos mandibulares em equinos.(AU)

Ensaio biomecânico para determinação do diâmetro de barra conectora de polimetilmetacrilato em fixador esquelético externo tipo Ia no úmero de suínos / Biomechanical test to determination the diameter of the polymethylmethacrylate bar in external skeletal fixator type Ia in swine humerusi

Fraturas ósseas podem ser corrigidas com a utilização de fixadores esqueléticos externos (FEE), método de estabilização bastante comum. Para tanto, têm-se utilizado barras conectoras de polimetilmetacrilato (PMMA) sem critério de diâmetro, as quais podem quebrar, se ficarem muito delgadas, ou ocasionar incômodo, quando muito pesadas e volumosas. O objetivo deste trabalho foi testar, por meio de ensaio biomecânico de compressão axial e flexão, qual é o diâmetro ideal da barra conectora de PMMA, correlacionado com o diâmetro ósseo para utilização em FEE tipo Ia. Utilizaram-se 24 úmeros para se realizarem medidas de comprimento, diâmetro, circunferência e ensaios biomecânicos. Após, foram confeccionadas barras de 1,5 vezes a média do diâmetro ósseo (grupo I), do mesmo diâmetro ósseo (grupo II) e de 0,5 vezes o diâmetro (grupo III). Com os resultados obtidos ao se compararem os valores dos ossos com os dos grupos II e III, verificou-se que as barras conectoras do grupo II mostraram-se mais resistentes do que o tecido ósseo no ensaio de compressão. No ensaio de flexão, os ossos resistiram mais quando comparados aos grupos II e III, sendo 4,3 vezes mais resistentes do que o grupo III nesse mesmo ensaio mecânico. Os resultados permitem um direcionamento para confecção de barras considerando-se o diâmetro ósseo como referência.(AU)

Bone fractures can be corrected from external skeletal fixators (ESF) in a fairly common internal stabilization method, in which connector bars polymethylmethacrylate (PMMA) is used. PMMA is used without criterion of diameter, and it can break if it is too thin or too heavy. It can be uncomfortable when bulky. The aim of this study was to test, through biomechanical axial compression and bending which is the ideal connector bar diameter PMMA, correlated to bone diameter for use in type Ia ESF. Twenty-four humerus were used to make measurements of length, diameter, circumference, and biomechanical testing. After the bars confected with 1.5 times the average diameter of the bone (group I), the same diameter (group II) and 0.5 times the diameter of the bone (group III). With the obtained results, using GII and GIII results, it was observed that the connector bars in group II were more resistant than the bones in the compression test. In the bending test, the bones resisted flexion strength when compared to group III and the group II was 4.3 times more resistant than group III in the same mechanical test. The results allow a direction for making bars considering bone diameter as a reference.(AU)