Browsing by Author "Mesquita, JR"
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- Canine hair follicular tumours: a retrospective studyPublication . Vala, Helena; Brito, M.; Esteves, Fernando; Cruz, R.; Santos, C.; Mega, A.C.; Nóbrega, C.; Mesquita, JR; Lemos, CHair follicular tumours in dog comprise a large and heterogeneous group of neoplasms that display morphological features resembling one or several portions of the normal hair follicle which constitute a huge effort for its diagnosis. Histopathological evaluation is required to better characterize the different types of canine hair follicular tumours, in order to better understand its biological behaviour and to collaborate with the daily clinical practice. Thus, a retrospective, cross-sectional descriptive study was carried out with goal of analyse its frequency and characteristics, in order to contribute to a better understanding of this vast group of tumours. As main results the authors verified a higher incidence of follicular tumours in male dogs, being the most frequent types diagnosed trichoepithelioma, followed by, trichoblastoma, infundibular keratinizing acanthoma and pilomatricoma and the average age of dogs was 8.76 years. Also, malignant tumours represented 31.6% of all canine hair follicular tumours diagnosed (n= 114).
- Rabbit thymic tissue – a potential marker for apoptosis techniques.Publication . Vala, Helena; Santos, C.; Cruz, R.; Nóbrega, C.; Ortiz, A. L.; Mesquita, JR; Esteves, F.; Mega, A.Background: Apoptosis detection methods have been proposed for diagnostic purposes, in particular for determining the biological characteristics of tumours and, indirectly, their prognosis. Implementation of a new technique requires the use of an effective positive control for correct assessment. Most specialty publications on the subject, do not indicate the positive controls used and do not disclose the obtained results therein. Objective: The aim of this work was to implement three different methods for the detection of apoptosis, using three canine tissue samples, consisting of breast cancer - carcinoma in situ, thymus and plasmacytoma; and a sample of rabbit tissues - thymus. Key words: Rabbit, thymus, immunohistochemistry, apoptosis, TUNEL, Bcl-2, Bax. Methods: Immunohistochemistry was performed, using pro- and antiapoptotic proteins, respectively, Bax and Bcl2 (1: 100; Santa Cruz, Biotechnology) and the TUNEL method (1: 2,5; In situ Cell Death Kit, Roche). Results Canine plasmacytoma revealed moderate positive reaction with all methods. Canine carcinoma in situ showed moderate positive reaction with pro-apoptotic antibodies and more intense with anti-apoptotic antibody. Dog’s thymus showed moderate positive reaction in cortical thymocytes with pro-apoptotic antibodies and weak in the medullary thymocytes. With the anti-apoptotic antibody, medullary thymocytes showed weak reaction and negativity in the cortex. Identical results were obtained in rabbit’s thymus, but with stronger intensity. Conclusions The rabbit thymus showed the most specific reaction of the tissues studied, by which the authors recommended it as a viable positive control for apoptosis studies.
- A rare case of retrobulbar neoplasia.Publication . Vala, Helena; Mega, A.; Santos, C.; Cruz, R.; Nóbrega, C.; Mesquita, JR; Esteves, F.; Vieira, F.; Ferraz, A.Introduction Neoplasms involving the optic nerve are rare. Intraorbital meningiomas, the most common tumour of the optic nerve, represent only 3% of all meningiomas in dogs, so few data exists to predict its symptoms and biologic behaviour. Objectives The authors describe and submit for discussion, a rare case of retrobulbar meningioma, in particular for assessment of histological grade and prognosis. Medical History A 10 year old Labrador Retriever male dog was presented for complaints of swelling and purulent discharge of the right eye. The animal had exophthalmos, protrusion of the third eyelid, chemosis, deep corneal ulceration and no pupillary light reflex. Exophthalmos due to a retrobulbar mass was diagnosed after physical, ophthalmic and ultrasound examination. Material and Methods The sample was fixed in 10 % buffered formalin solution, processed for routine histopathological diagnosis and a standard Streptavidin-Biotin Complex technique for immunohistochemical evaluation was also performed. Results Macroscopic examination revealed a conic mass, located in the retrobulbar portion of the optic nerve, adjacent to the posterior aspect of the globe with homogeneous, lobulated and whitish appearance and firm consistency. Microscopic examination revealed spindloid cells, with round-to-oval, finely stippled nuclei, small or indistinct nucleoli, moderate amount of eosinophilic cytoplasm, arranged in concentric whorls around capillaries, separated by interlacing fascicles, with small amount of well vascularized, collagenous stroma. Conclusion The authors suggested the diagnosis of transitional meningioma, based on the histopathological diagnosis and immunohistochemistry results.