Disuse osteoporosis occurs after extended periods of bed rest or nerve damage leading to increased risk of fracture. It remains to be established, however, whether the trajectory of bone loss is equivalent in bone's cortical and trabecular compartments following long-term periods of reduced loading. Herein, we evaluate sciatic neurectomy-related cortical and trabecular bone loss in the tibia by microCT. The right hind limb of seventeen 12 week-old female mice was subjected to sciatic neurectomy (right, SN; left, contralateral internal control) and the animals were sacrificed in four groups ( n = 3-5/group) at 5, 35, 65 and 95 days thereafter. Cortical bone mass, geometry and mineral density were evaluated along almost the entire tibial length and trabecular bone was examined at the proximal metaphysis. We found that trabecular bone volume (BV/TV) and number were decreased within 5 days, with a trajectory of loss that only plateaued after 65 days post-SN. In contrast, decreases in cortical thickness, cross-sectional area, second moment of inertia along minor and major axes and predicted resistance to torsion were unmodified during the early 5 day period, attaining significance only after 35 days post-SN and, thereafter showed no further deterioration. Only cortical ellipticity and periosteal enclosed area, continued to change in the SN limbs (vs. contralateral) between 35 and 95 days along the tibia length. On the other hand, cortical tissue mineral density was unmodified by SN at any time point. These data indicate that SN-related cortical bone loss extends along almost the entire tibia, exhibits delayed onset and yet stabilises its architecture more rapidly than trabecular bone. These data suggest that the cortical and trabecular compartments behave as distinct modules in response to SN even within an individual bone.

Changes in trabecular micro-architecture are key to our understanding of osteoporosis. Previous work focusing on structure model index (SMI) measurements have concluded that disease progression entails a shift from plates to rods in trabecular bone, but SMI is heavily biased by bone volume fraction. As an alternative to SMI, Ellipsoid Factor (EF) has been proposed as a continuous measure of local trabecular shape between plate-like and rod-like extremes. We investigated the relationship between EF distributions, SMI and bone volume fraction of the trabecular geometry in a murine model of disuse osteoporosis as well as from human vertebrae of differing bone volume fraction. We observed a moderate shift in EF median (at later disease stages in mouse tibia) and EF mode (in the vertebral samples with low bone volume fraction) towards a more rodlike geometry, but not in EF maximum and minimum. These results support the notion that the plate to rod transition does not coincide with the onset of bone loss and is considerably more moderate, when it does occur, than SMI suggests. A variety of local shapes not straightforward to categorise as rod or plate exist in all our trabecular bone samples.

RESUMOHá grande deficiência na literatura sobre os efeitos dos anestésicos dissociativos em animais silvestres. O objetivo do trabalho foi determinar os efeitos de diferentes protocolos anestésicos em cachorros-do-mato. Foram utilizados cinco animais machos, clinicamente sadios. Após 12 horas de jejum sólido, cada animal foi submetido a três protocolos de anestesia dissociativa (quetamina e xilazina -QX, quetamina e midazolam -QM e tiletamina e zolazepam -TZ) com intervalo de 30 dias entre eles. As variáveis avaliadas foram: período de latência; período hábil de anestesia; qualidade da indução, manutenção e recuperação anestésica. Foram avaliados frequência cardíaca (FC), saturação de oxihemoglobina (SpO 2 ), ritmo cardíaco, frequência respiratória (FR), temperatura corporal (TC) e relaxamento muscular aos cinco minutos após o período de latência e a cada 10 minutos durante o período de manutenção anestésica (M10 a M40). Os dados paramétricos foram submetidos à análise de variância e ao teste de Tukey, para comparação entre as médias dos grupos e dos tempos, sendo que as diferenças foram consideradas significativas quando p<0,05. O grupo QX apresentou um menor valor de FC em relação aos demais grupos em todos os momentos e observou-se maior incidência de arritmia sinusal. A FR apresentou menores valores no grupo QX em relação ao TZ. A SpO 2 apresentou diferença do grupo QX em relação ao QM somente no momento M10, sendo inferior neste último. Não foram observadas diferenças significativas no tempo de latência entre os grupos e os animais apresentaram boa qualidade de indução e recuperação, não apresentando efeitos adversos. Concluiu-se que a associação de quetamina e xilazina deve ser utilizada com cautela, pois proporciona maior redução na frequência cardíaca e arritmias. ABSTRACTIt is highly difficult to find literature references about the effects of dissociative anesthetics drugs on wild animals. This work aims to determine the effects of various anesthetic protocols on crab eating fox. Five healthy male animals were used. After 12 hours fast each animal were treated with three dissociative anesthesia protocols (QX -ketamine and xylazine, QM -ketamine and midazolam, TZ -tiletamine and zolazepam) at 30 days interval. The variables analyzed were: latency period; able anesthesia period; induction quality, anesthesia maintenance and recover. We available cardiac frequency (CF), oxyhemoglobin saturation (SpO 2 ), cardiac rhythm, respiratory frequency (RF), body temperature (BT) and muscle relaxing five minutes after the latency period and every 10 minutes during the period of anesthesia maintenance (M10 a M40). The parametric dates was analyzed by analysis of variance and Tukey test for comparison between the medium of groups and times, with significative difference fixed in p<0.05. The group QX showed lower CF valor compared with other groups in all the times and high incidence of sinus arrhythmia was observed. The RF showed lower valor in QX group compared with a TZ group. The SpO 2 showed difference between QX g...

Efeitos da morfina e da metadona associadas à acepromazina em gatas anestesiadas com propofol e halotano e submetidas à ovariossalpingohisterectomiaEffects of morphine and methadone associated with acepromazine in cats anesthetized with propofol and halothane and subjected to ovariossalpingohisterectomia RESUMO Os fármacos utilizados na medicação pré-anestésica são úteis para preparar o paciente para anestesia, causando sedação, analgesia, redução na dose dos anestésicos e menor incidência de efeitos adversos ao paciente. O objetivo deste trabalho foi avaliar os efeitos cardiovasculares e respiratórios, comportamentais, relaxamento muscular, analgesia pós-operatória da morfina ou metadona associadas à acepromazina em gatas anestesiadas com propofol e halotano e submetidas a ovariossalpingohisterectomia. Para isso, foram utilizadas 20 gatas clinicamente sadias, distribuídas em 2 grupos: o grupo I recebeu a associação de acepromazina (0,05mg/kg) e metadona (0,2mg/kg) e o grupo II recebeu a associação de acepromazina (0,05mg/kg) e morfina (0,2mg/kg) administradas na mesma seringa por via intramuscular. Foram avaliados frequência cardíaca e respiratória, pressão arterial sistólica, saturação de oxi-hemoglobina, concentração de dióxido de carbono no ar expirado, temperatura retal e tempo de preenchimento capilar, nos períodos pré, trans e pós-operatórios. Pode-se concluir que ambas as associações produziram leve sedação e podem ser utilizadas com segurança em felinos, pois promoveram boa analgesia sem efeitos colaterais. ABSTRACTThe pre-anesthetic medication is useful to prepare the patient for anesthesia, causing sedation, analgesia, reduction of the anesthetic gas doses and a lower incidence of adverse effects to the patient. Such variation of effects is dependent on the combination of drugs used. The aim of this study was to evaluate the cardiovascular and respiratory effects, behavioral, muscle relaxation, postoperative analgesia and influence on the quality and recovery period of morphine or methadone. For that were used 20 clinically healthy cats, divided into 2 groups: group I received the combination of acepromazine (0.05mg/kg) and methadone (0.2mg/kg) and group II received a combination of acepromazine (0.05mg/kg) and morphine (0.2mg/kg) administered in the same syringe for intramuscular injection. It was concluded that both associations produced mild sedation and can be used safely in cats, therefore providing good analgesia and muscle relaxation, without side effects.