Evaluation of root resorption associated with orthodontic movement in stressed rats.

AIM: The aim of this study was to investigate the effects of acute and chronic systemic stress response on orthodontically induced root resorption. METHODS: Male Wistar rats were restrained during 1 hour a day by stress models of short (3 days) and long duration (40 days), while control group was not submitted to restraint (N.=10/group). The upper left first molars of all rats were moved mesially by a fixed orthodontic appliance exerting 50 g force upon insertion during the last 14 days of the experiment. Then, animals were killed for blood collection and mensuration of plasmatic corticosterone by radioimmunoassay; the tissues around mesial root of the first molar were processed for histological and histochemical techniques with tartrate-resistant acid phosphatase. The degree of root resorption and the number of odontoclasts were evaluated, being the contralateral side of each animal serving as its control (split-mouth design). RESULTS: The results revealed that the plasmatic levels of corticosterone were significantly higher in both the stressed groups than in the control one. There were no significant differences in the degree of root resorption and in the number of odontoclasts on the root between the 3 groups studied. CONCLUSIONS: These results indicate that systemic stress alone can not be considered a risk factor for root resorption induced by orthodontic tooth movement.

Histological analysis of orthodontic root resorption in rats treated with the cyclooxygenase-2 (COX-2) inhibitor celecoxib.

INTRODUCTION: It has been reported that anti-inflammatory drugs used for treatment of pain and discomfort related to orthodontic treatment could slow down tooth movement. However, the effect of these drugs on orthodontic root resorption is not well understood. OBJECTIVES: The aim of this study was to investigate whether the COX-2 inhibitor celecoxib offers some protection against orthodontically induced root resorption. DESIGN: Male Wistar rats were divided into four groups: Groups I and II were treated with saline and celecoxib (10 mg / kg), respectively for 3 days. Groups III and IV were treated with saline and celecoxib for 14 days. The upper left first molars of all rats were moved mesially for 14 days with 50 g of force. An area including the disto-apical aspect of the mesial root of the first molar was processed for histological and histochemical techniques with tartarate-resistant acid phosphatase (TRAP). OUTCOME MEASURE: The degree of root resorption was measured using an image analysis system with a grid-sheet superimposed in the root were resorption lacunae were counted. The number of TRAP-positive cells on the tooth root surface defined as odontoclasts were also evaluated. RESULTS: The results revealed that there were no significant differences in the degree of root resorption and in the number of odontoclasts on the root between the four groups studied. CONCLUSION: The short and long-term celecoxib administration did not suppress the root resorption in case of experimental orthodontic force application.

Electromyographic analysis of the extending muscles of the knee during functional activities.

The purpose of this study is to analyze the behavior of electrical activity of the muscles vastus medialis oblique (VMO), vastus medialis long (VML), and, rectus femoris (RF) during functional activities. The electromyography of the VMO, VML and RF muscles were analyzed in ten healthy volunteers. Signs were collected through superficial electrodes and a electrogoniometer, connected to a signal condition module. The analysis of the results after treating the signals shows us that there is a similar electromyographical behavior in the three studied muscles. Therefore, these discoveries suggest a common electrical behavior pattern especially between VMO and VL muscles in healthy volunteers.

Efeito do exercício físico na hipertensäo renovascular crônica em ratos / Effect of physical exercises in chronic renovascular hypertension in rats

Este experimento foi realizado tendo por objetivo verificar a influência do exercício físico na pressäo arterial e no controle de peso corporal em ratos normais e ratos com hipertensäo renovascular crônica, pelo método de Godblatt um rim, um clipe (HG1). Foram utilizados 40 ratos Wistar com peso entre 150 e 200 g, divididos em 4 grupos: I e II - Normotensos com e sem exercício físico; IIIe IV - Hipertensos (HG1)com e sem exercício. O exercício físico constou de nataçäo durante 15 minutos, 2 vezes ao dia por 5 semanasconsecutivas. A pressäo arterial dos animais foi verificada aos 7, 14, 21, 28 e 35 dias por meio de um eletrosfigmógrafo (NARCOBIOSYSTEMS, Houston, USA), com cabos acoplados do microfone KOROTKOF e bomba de compressäo de cauda (cuff pump) e o peso corporal foi verificado diariamente antes do treinamento. Os resultados foram analisados, através do teste T de "Student" para dados pareados e näo-pareados. Pelo resultados obtidos observou-se, decorrente do exercício, que os animais normotensos apresentaram reduçäo significativa do ganho de peso corporal. Por outro lado, os animais hipertensos submetidos ao exercício físico, apresentaram uma reduçäo significativa de PA, sugerindo que nos animais hipertensos (HG1), submetidos ao exercício físico de nataçäo, por um período de 5 semanas, a pressäo arterial é mais sensível a alteraçöes do que o peso corporal. E que a nataçäo reduz o ganho de peso corporal em animais normotensos sem alterar de forma significativa a PA.

[Histological alterations in the submandibular glands and testicles in rats induced by soy and zinc deficient diet]. / Alterações histológicas de glândulas submandibulares e testículos induzidas por dietas à base de soja e dieta zinco deficiente em ratos.

The purpose of this study was to examine in rats the histologic alterations of the submandibular glands and testicles induced by soy diets and zinc deficient diet. The zinc deficiency produced testicles alterations including seminiferous tubulus atrophy, germinative epithelium degeneration, spermatogenesis alterations and a significant atrophy of the submandibular glands which presented no much delimitated acines. The soy diet without complementations also compromised the spermatogenesis by showing seminiferous tubulus atrophied and a reduction of the germinative epithelium. The soy diet complemented by saline and vitaminic mixtures didn't produced testicles alterations but its induced in the submandibular glands a hypertrophy of the ductal component mainly in relation to the granular component.

[Effect of dietary protein levels on the genesis of repair tissue in rats]. / Influência do teor protéico da dieta sobre a gênese do tecido de reparo em ratos.

The objective of this study was to verify if the diet protein level affects the genesis of the repair tissue in rats submitted to a poly-chloro-vinyl (PVC) sponge implantation, as well as to analyse the possible alterations in the synthesis of the mucopolysaccharides acids (glucosaminoglycans) by the histophotometry technique. Forty five Wistar weanling male rats, at 21 days of age, were divided into three experimental groups; the groups were fed diets al 6%, 15% and 40% protein level from casein source, during at 69 days period. The animals which received the low protein diet (6%) presented an inhibition in the evolution and maturation of the granulation tissue mainly in the 4th, 7th and 10th days after the sponge PVC implantation. It was also observed that there was less infiltration of the inflammatory cells, less fibroblasts proliferation, reduction of the collagen fibers synthesis, neovascularization decreased and an inhibition of the mucopolysaccharide acids synthesis.