Background: Cardiomyocytes have small potential for renovation and proliferation in vivo. Consequently, the heart muscle has limited capacity of self-renewal. Mesenchymal stem cells (MSC) therapy, as well as MSC differentiated into cardiomyocytes, has been used in the attempt to minimize the effects of ischemic-hypoxic lesions and those affecting the electrical conduction system of the heart.
Physical exercise is a known preventive and therapeutic alternative for several cerebrovascular diseases. Therefore, the objective of the present study was to evaluate the motor performance and histomorphometry of the biceps brachii, soleus, and tibialis anterior muscles of rats submitted to a treadmill training program prior to the induction of cerebral ischemia via occlusion of the middle cerebral artery (OMCA). A total of 24 Wistar rats were distributed into four groups: Sham-Sed: sedentary control animals (n=6), who underwent sham surgery (in which OMCA did not occur); Sham+Ex: control animals exercised before the sham surgery (n=6); I-Sed: sedentary animals with cerebral ischemia (n=6); and I+Ex: animals exercised before the induction of ischemia (n=6). The physical exercise consisted of treadmill training for five weeks, 30 min/day (5 days/week), at a speed of 14 m/min. The results showed that the type-I fibers presented greater fiber area in the exercised ischemic group (I+Ex: 2347.96±202.77 µm2) compared to the other groups (Sham-Sed: 1676.46±132.21 µm2; Sham+Ex: 1647.63±191.09 µm2; I+Ex: 1566.93±185.09 µm2; P=0.0002). Our findings suggested that the angiogenesis process may have influenced muscle recovery and reduced muscle atrophy of type-I fibers in the animals that exercised before cerebral ischemia.
Objetivo. O presente estudo investigou o desempenho motor e o volume de infarto cerebral em ratos sedentários ou que praticaram exercício físico antes e após a isquemia cerebral, promovida por oclusão transitória da artéria cerebral média (OACM). Método. Quarenta e oito ratos Wistar, foram randomizados em dois grupos, um submetido à OACM e o outro apresentando ausência da isquemia. Ambos os grupos foram subdivididos em AI (n=6): animais que realizaram exercício físico prévio a OACM; DI (n=6): animais que realizaram exercício físico após a OACM; ADI (n=6): animais que realizaram exercício físico antes e após a OACM e SI (n=6): animais que não realizaram exercício. O treinamento físico na esteira foi realizado por 6 semanas (30 min/dia), 5 dias na semana. Resultados. Os resultados demonstraram perda de peso nos animais SI após o procedimento de OACM (81 dias) e no final do experimento no grupo ADI (p<0,0001). Os animais dos grupos AI e ADI apresentaram menor frequência de erros no teste passo em falso e barras paralelas aos 76 dias. Conclusão. Ao final do experimento o grupo ADI apresentou melhor desempenho motor nos testes funcionais e menor volume de infarto cerebral.
RESUMOThe effects of volume on lumbosacral epidural block in dogs were evaluated using two different doses of 2% lidocaine. Ten adult dogs, without defined breed, were subjected to two different anesthetic protocols. In the first, the local anesthetic was calculated based on the body weight (GP), wherein 1.0 mL of local anesthetic was used for each 3.5 kg; in the second protocol, the dose was stipulated according to the occipito-coccygeal (DG) distance with 1.5mL of local anesthetic for every 10 cm of distance. The available time, recovery period, extent of block, and rectal temperature were measured. After the analysis of the results, it was possible to verify that there was an increase in the time in GD when compared with GP, due to the greater volume administered in that group. The recovery period remained similar in both groups, despite the use of different doses. Regarding the extent of blockade, there was an increase in GD in relation to GP due to the increase of the local anesthetic dose. On the other hand, the rectal temperature presented a difference between the groups, remaining lower and below the reference values for the species in GD compared with GP at all moments analyzed, possibly due to a sympathetic action triggered by the cranial extension of the epidural block. It could be concluded that when a longer time and a more cranial blockade of epidural anesthesia are desired, the anesthesia volume should be based on the occipito-coccygeal distance, however, observing the rectal temperature.Key words: lidocaine; volume; timing; recovery time; rectal temperature. Gisele Martins de Paula Estudo comparativo da anestesia epidural em cães por peso ou distância ocipto-coccígeaAvaliaram-se os efeitos do volume no bloqueio epidural lombossacro em cães utilizando-se duas doses diferentes de lidocaína a 2%. Foram utilizados dez cães adultos, SRD submetidos: No primeiro protocolo, o anestésico local foi calculado com base no peso corporal (GP) e no segundo protocolo a dose foi estipulada de acordo com a distância ocipto-coccígea (GD). Sendo os mesmos animais submetidos aos dois protocolos anestésicos, com intervalo de dez dias. Mensurou-se o tempo hábil, o período de recuperação, a extensão do bloqueio e a temperatura retal. Após a análise dos resultados foi possível constatar que houve acréscimo no tempo hábil em GD quando comparado a GP, devido ao maior volume administrado em tal grupo. O período de recuperação se manteve semelhante em ambos os grupos, apesar do uso de doses diferentes. Com relação à extensão do bloqueio, houve um aumento em GD quando comparado a GP devido ao aumento da dose de anestésico local. Já a temperatura retal apresentou diferença entre os grupos, mantendose menor e abaixo dos valores de referência para a espécie, em GD na comparação com GP em todos os momentos analisados possivelmente devido a uma ação simpática desencadeada pela extensão cranial do bloqueio epidural. Pode se concluir que quando se dejesa um maior tempo hábil e um bloqueio mais cranial de anestesia epidural...
The mechanisms of production, and gross, microscopic and electrocardiograhic findings of surgically-induced complete heart block (CHB) in the adult rat are presented. This is an effective in vivo model for establishing alternative methods to electronic pacemakers and for providing detailed information aimed at replacement, reduction and refinement of the technique. Sternal thoracotomy was employed to identify the epicardial fat pad by the aortic root, used as a landmark for cauterization of the atrioventricular (AV) node. Stable CHB was produced in 60 rats with a 70% survival rate. The best survival rate was observed in 8-week-old animals weighing 221 ± 27.6 g. Heart rate before cauterization was 387 ± 55 bpm, reduced after cauterization to 126 ± 40 bpm in the survival and to 65 ± 19 bpm in the non-survival groups. At 30 days findings were: elevated left ventricular end-diastolic pressure (21 ± 5.4 mmHg, P < 0.05); maximal rate of rise of left ventricular pressure (LVP) during isovolumetric contraction (2192 ± 235 mmHg/s, P < 0.05); maximal rate of decrease of LVP (-1658 ± 191 mmHg/s, P < 0.05); isovolumetric relaxation constant (5.7 ± 0.8 ms, P < 0.05) with wet-to-dry lung-weight ratio (78.1 ± 0.4, P < 0.05); heart weight/body weight (0.6 ± 0.1, P < 0.05); heart volume (1.8 ± 0.3 mL, P < 0.05); longitudinal diameter (20.2 ± 1.91 mm, P < 0.05); and transversal diameter (17.0 ± 1.4 mm, P < 0.05) with supported dilated cardiomyopathy which culminated in chronic heart failure. CHB hearts had increased preload and replacement of myofibrils by collagen. CHB was achieved reproducibly by cauterization of the rat AV node and/or His bundle. This led to electrophysiological, hemodynamic, and structural remodeling, and could be useful in long-term cardiac remodeling assessments and potential therapy development.
Maneuvers to activate the equine's core can make a difference in their physical and psychic health. Although these activities are recommended and practiced, there is little research proving their effectiveness. This article aims to describe, through surface electromyography, the occurrences, durations and sequences activity of longissimus dorsi, rectus abdominis and gluteus medius during thoracolumbar flexion (TLF), lumbar and lumbosacral flexion (LLSF), global flexion (GF), which is the combination of TLF and LLSF, and tail traction (TT). Seven healthy adult horses of three different breeds performed five repetitions of these movements for five seconds (sec). Electromyographic activity was captured with non-invasive superficial sensors positioned in the skin regions covering these muscles. The sequence was performed once per animal, muscle activity captured by surface electromyography, data from two replicates of each animal were selected, analyzed on matLab software and data tabulation were described during each maneuver. These maneuvers provoked punctual and transient activation of muscles mentioned above, confirming the ability to activate equine core muscles. However, responses were not standardized, which means there were variations of occurrence, duration and sequence, suggesting that for practical application of those maneuvers it is necessary to perform more repetitions with longer durations to activate more muscles.
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