Browsing by Author "Rodrigues, D."
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- Effects of intense pulsed light on skin carcinogenesisPublication . Faustino-Rocha, AI; Gama, A.; Rodrigues, D.; Colaço, B.; Vala, Helena; Pires, MJ; Oliveira, PAObjective: Intense pulsed light (IPL) is a non-laser high intensity light that has been used to the treatment of several skin conditions. This work intended to evaluate the effects of IPL on a mouse model of two-stage skin carcinogenesis. Methods: Procedures were made in accordance with the Directive 2010/63/EU. Sixteen DBA/2JRccHsd mice were divided into two groups: IPL-exposed and non-exposed. The carcinogen agent DMBA was topically applied once and TPA was applied twice a week during 22 weeks. Animals IPL-exposed received IPL applications twice a week, at an intensity of 2J/cm2 during 22 weeks. Animals were sacrificed and skin samples were histologically evaluated. Results: Animals IPL-exposed developed 44 skin lesions (5.5 lesions per animal) while non-exposed animals developed 63 lesions (7.9 lesions per animal) (p=0.066). The animals IPL-exposed developed 20 skin neoplastic lesions while non-exposed animals developed 38 lesions (p=0.018), however the number of malignant lesions was higher in IPL-exposed animals (3 lesions) than in non-exposed animals (1 lesion) (p>0.05). Conclusion: The animals IPL-exposed developed lower number of skin lesions and neoplastic lesions, but the number of malignant lesions was higher. IPL inhibits the development of skin lesions but may have a promoting effect on the malignant conversion.
- Effects of trihalomethanes on liver: a mouse modelPublication . Faustino-Rocha, A.I.; Rodrigues, D.; Vala, Helena; Pires, M.J.; Colaço, A.; Oliveira, P.A.Introduction and objectives: Trihalomethanes (THMs) are disinfection byproducts found in chlorinated water. They are associated with cancer of various organs in human populations and experimental animal models. The aim of this study was to evaluate by histopathology the hepatic changes induced by THMs administered at low levels in a mouse model. Materials and methods: All procedures were made in accordance to the European Directive 2010/63/EU. Forty-two ICR male mice were randomly divided into 4 experimental groups: DBCM-exposed (n=11), BDCM-exposed (n=11), methanol-exposed (n=11) and a negative control (n=9). Animals from DBCM, BDCM and methanol-exposed groups received dibromochloromethane (DBCM), bromodichloromethane (BDCM) and methanol, respectively at a concentration of 117µg/Kg, once daily, by gavage, to a total of four administrations. Animals from control group only received water. Animals were sacrificed 4 weeks after DBCM, BDCM and methanol administrations. Blood biochemistry was performed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TB), albumin (Alb), total protein (TP), creatinine and urea. Hepatic samples were histopathological evaluated using hematoxylin and eosin (H&E), reticulin and Masson’s trichrome methods. Results: During the experimental protocol, 12 animals died and were excluded from the study. Animals exposed to THMs showed high levels of ALT and TB compared with methanol and control groups (p < 0.05). Histopathological analysis did not reveal any hepatic architectural changes. However, animals from the DBCM, BDCM and methanol groups exhibited multifocal inflammatory cell infiltrates, multifocal hepatocellular necrosis and cytoplasmic vacuolar degeneration, most frequently in the DBCM and BDCM-exposed groups. Hepatocellular nuclei exhibited a disperse chromatin pattern and prominent nucleoli in all animals from DBCM, BDCM and methanol-exposed groups. Reticulin and Masson’s trichrome methods showed normal collagen expression patterns in all groups, with no differences between exposed and control animals. Conclusions: The high levels of blood markers of hepatocellular damage (ALT and TB) and the histopathological findings indicate that both THMs, DBCM and BDCM when ingested at low doses exert toxic effects on hepatocytes.
- Hip Dysplasia in Dogs: Control and PreventionPublication . Rodrigues, D.; Ortiz, V.; Vala, Helena; Santos, C.; Oliveira, A. L.Hip dysplasia (HD) is an orthopaedic pathology with high prevalence in dogs, especially in large and giant breeds. It has a polygenic origin and is influenced by several factors such as age, sex, nutrition, metabolism, physical activity and hormones. Animals affected with this disease are born with normal joints but as they develop, joint changes appear. These changes may be expressed by lameness, gait abnormalities, hip instability and pain in full extension of the joint. To reduce the HD prevalence, selective breeding programmes have been implemented in which only animals free of disease or with minimal articular changes can reproduce. As these programmes do not always have the desired success, early radiographs should be performed in susceptible animals, in order to slow the progression of changes. The aim of this review is to summarize canine HD control and prevention aspects, with reference to the factors that predispose to disease, and the various treatment options. The role played by the veterinary nurse in advising the HD dog owners on disease management and also on how to avoid the risk factors in order to reduce the number of affected animals, is also discussed