Browsing by Author "Gama, A."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Effects of histamine on the development of MNU-induced mammary tumoursPublication . Faustino-Rocha AI, A. I.; Gama, A.; Oliveira, P. A.; Vala, Helena; Ferreira, R.; Ginja, M.Objective: Breast cancer is frequently diagnosed worldwide. Histamine acts as mediator in several cancers. Ketotifen is a mast cells stabilizer drug that inhibits their degranulation. This work aimed to evaluate the effects of histamine on the development of MNU-induced mammary tumors. Methods: Procedures followed the European Directive 2010/63/EU. Twenty animals were equally divided into two experimental groups: ketotifen and control. At seven weeks of age, all animals received an intraperitoneal injection of N-methyl-N-nitrosourea (MNU). Animals from ketotifen group received ketotifen in drinking water (1mg/Kg; 7days/week; for 18 weeks). At the sacrifice, mammary tumors were fixed and histologically evaluated. Results: During the protocol one ketotifen-treated animal died. At the end, eight animals from ketotifen group developed 19 mammary tumors (2.4 tumors per animal), while six animals from control group developed 21 mammary tumors (3.5 tumors per animal). Animals from control group developed one benign lesion and 20 non-invasive carcinoma; all lesions from ketotifen-treated animals were malignant, however they did not develop any comedo carcinoma that was the lesion of the highest grade of malignancy found in this work. Conclusion: Inhibition of histamine release by ketotifen seems to reduce the number and malignancy of MNU-induced mammary tumors.
- 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.
- Expression of estrogen receptors-α and β in chemically-induced mammary tumoursPublication . Faustino-Rocha, A. I.; Gama, A.; Oliveira, P. A.; Alvarado, A.; Vala, Helena; Ferreira, R.; Ginja, M.Objective: Estrogen receptors (ERs)-α and β are important for stimulating the growth and differentiation of human mammary tumours, respectively. This work aimed to evaluate the expression of ERs-α and β in rat chemically-induced mammary tumours. Methods: Procedures followed the European legislation (2010/63/EU). Fifteen seven-week-old female Sprague-Dawley rats received an intraperitoneal injection of N-methyl-N-nitrosourea (MNU) (50mg/Kg). At sacrifice, mammary tumours were fixed and histologically evaluated. Sections were incubated with ER-α and β primary antibodies and the percentage of immunopositive cells was determined. Results: During the experimental protocol four animals died, all survived animals developed mammary tumours: 30 benign, 2 preneoplastic and 39 malignant lesions. All histological patterns expressed ERs-α and β. The mean expression of ER-α (55.14% ± 13.26) was lower than the expression of ER-β (70.06% ± 18.51) (p<0.05). The expression of both receptors was not statistically different among lesions, however it was higher in preneoplastic lesions, followed by malignant and benign ones (p>0.05). Conclusion: All MNU-induced mammary tumours in rats expressed ERs-α and β, being a good model of ER-positive human mammary tumours. Once the expression of ER-β was higher, tumours’ differentiation was stimulated and its proliferation was inhibited.
- Walking against cancer: the impact of long-term exercise training on mammary tumorsPublication . Rocha, A. I. Faustino; Oliveira, P. A.; Gama, A.; Vala, Helena; Esteves, Fernando; Ferreira, R.; Ginja, M.Breast cancer is one of the most frequent cancers among women worldwide. The present work evaluated the effects of long-term exercise training on the development of chemically-induced mammary cancer. Materials and Methods: Procedures followed the European legislation and were approved by the Portuguese Ethics Committee (DGAV, approval nº008961). Thirty 7-week-old female Sprague-Dawley rats were intraperitoneally injected with the carcinogen N-methyl-N-nitrosourea (MNU) (50mg/Kg). After this, they were randomly divided into two experimental groups: sedentary (n=15) and exercised (n=15). Exercised animals were trained on a treadmill for 35 weeks. At the end of the study, the mammary tumors were collected, fixated in formalin and histologically evaluated. The expression of estrogen receptor (ER)α was assessed by immunohistochemistry. Results: An incidence of 100% was observed. A total of 51 mammary tumors was developed: 28 in sedentary group and 23 in exercised one (p>0.05). At histopathological analysis, it was observed that each mammary tumor exhibited more than one histological pattern. A total of 121 mammary lesions was counted: 71 in sedentary group and 50 in exercised group (p=0.056). The number of malignant lesions was higher in sedentary group when compared with the exercised one (39 versus 21) (p=0.020). All mammary lesions exhibited nuclear immunostaining for ERα; the immunoexpression was higher in exercised group when compared with the sedentary one (p<0.05). Conclusions: Long-term exercise training reduced the number and malignancy of mammary tumors. Additionally, it increased the ERα immunoexpression that is an indicator of tumor differentiation and better response to hormone therapy.