Determinação de desmineralização óssea em gatos após tirotoxicose experimental

Hyperthyroidism can result in serious effects on the bone metabolism in humans as well as animals. For a better characterization of thyrotoxicosis effects, 16 cats were induced into thyrotoxicosis by intaking a dose of 150 μg/kg of sodium L-thyroxine every 24 hours during 42 days. The hormonal levels were evaluated by radioimmunoassay technique and the bone mineral density of the right distal radius extremity was measured through the radiographic optical densitometry. Was verified significant bone demineralization seven days of hormonal intake as weel as radius demineralization.

The use of planarians as in vivo animal model to study laser biomodulation effects

A variety of effects is attributed to the photo stimulation of tissues, such as improved healing of ulcers, analgesic and anti-inflammatory effects, stimulation of the proliferation of cells of different origins and stimulation of bone repair. Some investigations that make qualitative evaluations, like wound healing and evaluation of pain and edema, can be conducted in human subjects. However, deeper investigations on the mechanisms of action of the light stimulus and other quantitative works that requires biopsies or destructive analysis has to be carried out in animal models or in cell cultures. In this work, we propose the use of planarians as a model to study laser-tissue interaction. Contrasting with cell cultures and unicellular organisms, planarians are among the simplest organism having tissue layers, central nerve system, digestive and excretory system that might have been platforms for the evolution of the complex and highly organized tissues and organs found in higher organisms. For the present study, 685 nm laser radiation was employed. Planarians were cut transversally, in a plane posterior to the auricles. The body fragments were left to regenerate and the proliferation dynamics of stem cells was studied by using histological analysis. Maximum cell count was obtained for the laser treated group at the 4th experimental day. At that experimental time, we also had the largest difference between the irradiated and the non-irradiated control group. We concluded that the studied flatworm could be an interesting animal model for in vivo studies of laser-tissue interactions.

Experimental model of pulmonary carcinogenesis in Wistar rats

Purpose: To elaborate an experimental model of pulmonary carcinogenesis in Wistar rats. Methods: Male Rattus norvegicus albinus, Wistar lineage was carried through an intra-pulmonary instillation of the Benzo[a]pyrene (B[a]P) dilution in alcohol 70%, a polycyclic aromatic hydrocarbon widely known by its power of tumoral induction. Three experimental groups had been formed with 08 animals each: Control Group (Alcohol 70%); B[a]P Group 10 mg/kg; e B[a]P Group 20mg/ kg, submitted to euthanasia 08, 10, 12 and 14 weeks after the experimental procedure. The pulmonary sections had been colored by hematoxilin-eosin (HE) and submitted to the morphometrical analysis to describe the tissue alterations. Results: The presence of diffuse inflammatory alterations was observed in all groups, however, at the analysis of the pulmonary tissue of the experimental groups, it had been observed hyperplasic alterations (BALT hyperplasia), and in one of the animals of the experimental group 20mg/kg (12 weeks), it was noticed the presence of cellular epithelial tracheal pleomorphism, suggesting the adenocarcinoma formation in situ. Conclusion: The main secondary alterations to the intra-pulmonary instillation of B[a]P in Wistar rats were: cellular proliferation, inflammatory alterations of several degrees and nodular lymphoid hyperplasias. The association of an activator agent of the pulmonary metabolic reply is necessary to establish the ideal reply-dose to the development of the lung cancer.

Use of fibrin glue derived from snake venom in the repair of deep corneal ulcers - Experimental study in dogs (Canis familiaris, Linnaeus, 1758)

Fibrin glue has been researched as an alternative method for tissue synthesis and is known for its capability to promote hemostasis at the application site, good approximation of wound edges and fast healing. The current study consisted in the application of fibrin glue derived from snake venom as treatment for experimental corneal ulcers. Twenty-one dogs had their corneas experimentally prepared through lamellar keratectomy (of standardized diameter and depth). Animals were divided into seven groups of three animals each. Six experimental groups were periodically evaluated and collection was carried out on the 1st, 3rd, 7th, 15 th, 30th and 60th post-operative days, whereas one control group was evaluated throughout the experiment. Analyses consisted in the clinical evolution and in the histopathological study of all operated on eyes. Results indicated that fibrin glue was efficient in repairing keratectomy wounds in dogs and contributed to an earlier healing phenomenon, avoiding edema formation and keeping corneal clearness. The use of fibrin glue derived from snake venom showed to be easy to apply, feasible with animal models and of low cost, avoiding the lesion progress and allowing fast and appropriate corneal healing.

Estudo comparativo experimental da injeção perineural do álcool benzílico 0,75% e do álcool etílico absoluto nos nervos palmares de eqüinos

The clinical and histopathological effects of two alcoholic neurolytics were studied in horses. Normal horses were shod with a designed shoe adaptted with 5 screws to produce solar pain. After gait and lameness score analysis, the palmar nerve of 5 horses was injected with 5 ml of 0,75% benzyl alcohol (Group A) and 5 horses were injected with 5 ml of absolute ethyl alcohol (Group B). The animals were submitted to regular lameness evaluation and solar sensibility tests during next six months. The solar sensitivity returned 5 months latter in the group injected with benzyl alcohol 0,75%, while in the group injected with absolute ethyl alcohol, the sole was still desensitized 6 months latter. The histopathological findings showed that the nerve injected with benzyl alcohol 0,75%, resulted in axonotmesis, characterized by axonal nerve degeneration, with possibilities for the nerve conduction recovery. The perineural injection of ethyl alcohol absolute, resulted in neurotmesis with difficult nerve regeneration. It was concluded that chemical neurolysis with alcohol is an option for temporary or permanent nerve blocks in horses.

Mensuração do tamanho cardíaco em radiografias de gatos com hipertireoidismo experimental

Feline hyperthyroidism (thyrotoxicosis) is now recognised as the most common endocrine disease of the domestic cat. Feline hyperthyroidism cause multisystemic disorder associated with incresead circulating concentrations of the thyroid hormones, tri-iodothyronine (T3) and thyroxine (T4). Cardiovascular abnormalities in cats with spontaneous hyperthyroid have been described. Objective to determine heart size of progressing experimental thyrotoxicosis of 19 cats, using a vertebral scale system (VHS). The lateral, dorsoventral e ventrodorsal radiographs thoracic were measured using a vertebral scale system. Lateral radiographs thoracic to efficient develop that DV and VD. The VHS method is easy to use, allows objective assesment of heart size in cats hyperthyroid, and may be helpful to identify cardiomegaly and heart size progressing.

Resin bonding to root canal dentin: Effect of the application of an experimental hydrophobic resin coating after an all-in-one adhesive

Aim: Based on the hypothesis the application of a low-viscosity hydrophobic resin coating improves the bond of all-in-one adhesive, the purpose of the study was to evaluate the bond strength of four adhesive systems to bovine root dentin using the push-out test method. Methods and Materials: The root canals of 32 bovine roots (16 mm) were prepared to a length of 12 mm using a FRC Postec Plus preparation drill. The specimens were allocated into four groups according to the adhesive system used: (Group 1) All-in-one Xeno III; (Group 2) All-in-one Xeno III+ScotchBond Multi-Purpose Plus Adhesive; (Group 3) Simplified Etch & Rinse One Step Plus; and (Group 4) Multi-Bottle Etch & Rinse All-Bond 2. A fiber-reinforced composite retention post was reproduced using an additional silicon impression and fabricated with DuoLink resin cement. The root specimens were treated with the selected adhesive systems, and the resin posts were luted in the canals with DuoLink resin cement. Each root specimen was cross sectioned into four samples (±1.8 mm in thickness), and the post sections were pushed-out to determine the bond strength to dentin. Results: Group 2 (2.9±1.2) was statistically higher than Group 1 (1.1±0.5) and Group 3 (1.1±0.5). Groups 1 and 3 showed no statistically significant difference while Group 4 (2.0±0.7) presented similar values (p>0.05) to Groups 1, 2, and 3 [(one-way analysis of variance (ANOVA)] and Tukey test, α=0.05). Conclusion: The hypothesis was accepted since the application of the additional layer of a low-viscosity bonding resin improved the bond of the all-in-one adhesive. Further studies must be conducted to evaluate the long-term bond.

Infarto do miocárdio experimental em ratos: Análise do modelo

One of the most often used strategies to study the physiopathological alterations caused by coronary occlusion is the use of the experimental infarction model in rats. Among other factors, this is due to the similarities in the physiopathological alterations that occur after the infarction in humans. One must consider, however, that this model has characteristics that can hinder the use as well as the interpretation of eventual outcomes. Thus, this review aims at analyzing the main characteristics of the experimental infarction model in rats, discussing the coronary occlusion technique, the consequences and the methods of morphological and functional assessment of the infarction and its clinical implications.

Autologous orbicularis muscle for filling facial foldsan experimental and clinical study

Purpose: To present a technique for filling facial folds by using autologous orbicularis oculi muscle, based on an experimental model. Methods: two studies are presented: (1) an experimental study using 15 albino guinea-pigs from which a strip of the sural triceps muscle was removed and implanted in the subcutaneous tissue of the dorsal area. The animals were sacrificed 7, 30 and 60 days after the implantation, and the material was histologically evaluated. And (2%) an interventional prospective clinical trial carried out on 20 patients referred to blepharoplasty surgery. They received autologous preseptal orbicularis muscle for filling facial folds. The results where evaluated by patients satisfaction and clinical exam. Results: the sural tricep muscle, when implanted in the subcutaneous tissue, resulted in fibrosis. The patients whom received autologous orbicularis muscle implanted for filling facial folds showed that the procedure can be successfully carried out. Conclusions: autologous preseptal orbicularis muscle is a good material for filling facial folds. Cicatricial tissue will be formed on its implantation site, filling the tissue gap that forms the folds on the skin.

Correlação entre a densidade mineral óssea e níveis séricos de cálcio, fósforo e fosfatase alcalina total em gatos após tirotoxicose experimental

Hyperthyroidism is and endocrinal dysfunction characterized by excessive serum concentrations of thyroid gland hormones, which can cause several effects on the bone tissue in humans and in animals. For a better characterization of thyrotoxicosis effects on bone metabolism, 16 cats were induced into hyperthyroid state. Results showed that, in some moments a major bone demineralization of the right distal radium estremity promoted an elevation of the serum levels of phosphorus and total alkaline phosphatase.

Treatment of experimental periodontal disease by a selective inhibitor of cyclooxygenase-2 with scaling and root planing (SRP)

Lumiracoxib is a selective inhibitor of cyclooxygenase-2 (COX-2) approved for the relief of symptoms of chronic inflammatory conditions. The aim of this study was to evaluate the effects of this specific inhibitor of COX-2 as adjunctive treatment on induced periodontitis in rats. Periodontal disease was induced at the first mandibular molar of 60 rats. After 7 days, the ligature was removed and all animals were submitted to scaling and root planing (SRP) along with local irrigation with saline solution and were divided into 2 groups: SRP (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of saline solution for 3 days and; SRP + L (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of Lumiracoxib for 3 days. Ten animals in each group were killed at 7, 15, and 30 days. The histological description was performed and the histometric values were statistically analyzed. In Group SRP + L, the histometric analysis (0.58 ± 0.08, 0.64 ± 0.06, and 0.56 ± 0.10 mm 2) showed less bone loss (p < 0.05) than Group SRP (1.52 ± 0.08, 1.55 ± 0.09, and 1.49 ± 0.24 mm 2) at 7, 15, and 30 days, respectively. Within the limits of this study it can be concluded that subcutaneous application of specific inhibitor of COX-2 was a beneficial adjunctive treatment for periodontal diseases induced in rats. © 2010 Springer Basel AG.

Modelo experimental de úlcera traumática em mucosa jugal de ratos

Purpose: To establish an experimental model of traumatic ulcer in rat cheek mucosa for utilization in future alternative therapy studies. Methods: A total of 60 adult male rats (250 - 300g) were used. Ulceration of the left cheek mucosa was provoked by abrasion using a n o 15 scalpel blade. The animals were observed for 10 days, during which they were weighed and their ulcers were measured. The histological characteristics were analyzed and scored according to the ulcer phase. In the statistical analysis, a value of p<0.01 was considered a statistically significant response in all cases. Results: During the five first days, the animals lost weight (Student t test, p<0.01). The ulcerated area receded linearly over time and was almost completely cicatrized after 10 days (ANOVA, Tendency post-test, p<0.0001). Groups on days 1, 2 and 3 days displayed similar results, but a decrease in scores were observed after the 4th day. Conclusion: The proposed cheek mucosa ulcer model in rats can be considered an efficient, low-cost, reliable, and reproducible method.