José Guilherme Xavier

Tuberculosis lymphadenitis in slaughtered swine from S. Paulo State (Brazil): gross lesions, histopathology and demonstration of mycobacteria

INTRODUCTION: As the occurrence of tuberculosis lymphadenitis in swine constitutes a public health risk, especially in immunosuppressed individuals, the distribution of tuberculoid lesions and the presence of micobacteria in lymphonodes and hepatic and muscular tissue in swine for slaughter, in the State of S. Paulo, SP (Brazil), in the period from 1993 to 1994, were studied. MATERIAL E METODO: Tuberculous lesions in 60 carcasses of swine, slaughtered at abattoirs during the period 1993-1994, were studied. When macroscopic lesions were observed, a representative sampling of lymphnodes, hepatic and muscular tissues (masseter and diaphragm) were examined using histophatological and micobacterial isolation techniques. RESULTS: The macroscopic lesions were found predominantly in mesenteric lymphnodes. The MAI Complex (M.avium-intracellulare) was isolated mainly in the carcass group that showed lesions and was not found in the control group. Microorganisms of the MAI Complex were not isolated from hepatic and muscular tissues. CONCLUSION: No clear relationship between the type of mycobacteria isolated and the macroscopic lesions observed during the carcass inspection was found.INTRODUCAO: Como a ocorrencia de linfadenites tuberculoides nos suinos oferece riscos a saude publica, sobretudo em individuos imunocomprometidos, foi estudada a distribuicao das lesoes tuberculoides e a presenca de micobacterias em linfonodos, tecido hepatico e muscular de suinos de abate, no Estado de Sao Paulo, SP (Brasil), no periodo de 1993-1994. MATERIAL E METODO: Foram estudadas 60 carcacas de suinos abatidos, sendo que, trinta apresentavam lesoes tuberculoides macroscopicas (grupo A) e trinta estavam livres de tais lesoes (grupo B ou controle). Foram analisadas seis localizacoes: linfonodos (retrofaringeos, jejunais e mediastinicos), tecido hepatico e tecido muscular (masseter e diafragma). Os exames executados foram: histopatologia e o cultivo para micobacterias. RESULTADOS: No grupo A, 14 em 30 carcacas apresentaram granuloma na histopatologia e, em 14, houve o isolamento de representantes do Complexo MAC (Mycobacterium avium-intracellulare). No grupo B nao foram observadas lesoes na histopatologia, e de quatro carcacas houve o isolamento de micobacterias de rapido crescimento. As lesoes macroscopicas foram encontradas predominantemente nos linfonodos mesentericos. O Complexo MAC foi isolado apenas em linfonodos do grupo com lesao, nao sendo isolado em tecido hepatico e muscular. CONCLUSAO: Nao foi possivel o estabelecimento de relacao entre o tipo de micobacteria isolada e as caracteristicas macroscopicas das lesoes.

Effect of haloperidol on the development of the solid ehrlich tumor in mice

We determined the effect of 13 days of treatment with 2.0 mg/kg haloperidol (s.c) on the development of the Ehrlich solid carcinoma, after inoculation of 1.5 x 10(6) Ehrlich ascites tumor cells into the left footpad of mice. The footpad thickness of haloperidol treated animals was significantly smaller than control from day two after tumor inoculation, to the end of the experiment. Histopathological examination showed that haloperidol treated mice apparently presented less necrotic areas within the tumor mass as well as less invasion of subepithelial connective tissue and other adjacent structures. In particular, in comparison with the control group, no nerve bundles were invaded by neoplastic cells in experimental mice. The possible mechanism underlying these results is discussed in light of the specific pharmacological properties of this neuroleptics drug.

Acute effect of aflatoxin B1 on different inbred mouse strains II

The acute effects of Aflatoxin B1(AFB1) were evaluated on C57B1/6, CBA/J, B10A and Balb/c mice challenged with a single intraperitoneal dose of the mycotoxin (60 mg/Kg animal weight). 90 mice per strain were divided into three groups of 30 animals each: the intoxicated group and control groups I and II. Intoxicated mice were injected intraperitonealy with AFB1 dissolved in corn oil, while control I mice received corn oil only (0.01 ml/g) by the same route. Lots of 10 animals from the intoxicated and control groups were sacrificed 24, 72 and 168 hours after challenge. Control mice II remained untreated and were used as standards of normality for biochemical (hepatic and renal function) and hematological evaluation. AFB1 was detected in the liver of C57B1/6 and CBA/J mice 24 hours (1.46 and 0.75 ng/g, respectively), 72 hours (2.30 and 0.08 ng/g, respectively), and 168 hours (2.18 and 0.25 ng/g, respectively) after challenge. The mycotoxin was also observed in the liver of B10A mice (6.20 ng/g) 72 hours post-injection. The most evident histological lesions were observed 168 hours after treatment in C57B1/6 and B10A mice. Serum levels of alkaline phosphatase in intoxicated C57B1/6 and B10A mice were significantly higher than those of control I and II animals. The histopathologic lesions and biochemical changes were very discrete in Balb/c and CBA/J mice. It is included that strains C57B1/6 and B10A are more susceptible than strains CBA/J and Balb/c to the acute effects of AFB1. Such difference probably reflects each strainss ability to biotransform and eliminate AFB1 and its metabolites.

Avaliação da proliferação celular como indicador prognóstico para mastocitomas cutâneos caninos

This study evaluated the prognostic value of cell proliferation markers for canine cutaneous mast cell tumor cases. Twenty-three cases were analyzed with regard to immuno-histochemical expression of Ki67 and Proliferating Cell Nuclear Antigen (PCNA), and were clinically followed up. Ki67 expression was related to the traditional histopathological grading (p= 0.0418; p<0.05 between grades I and III), and was a reliable indicator of post-surgical survival (p=0.0089). PCNA immunoexpression did not show statistically significant values in the prediction of disease-related mortality and survival, although it is correlated to Ki67 expression. These results confirm that information about tumoral proliferative activity through Ki67 immunohistochemical detection can improve canine cutaneous mast cell tumor grading with regard to malignancy.

Cyclophosphamide immunosuppressed Xid mice model clarify the protective role of B cells in experimental encephalitozoonosis

Encephalitozoon cuniculi is an intracellular pathogen that stablishes a balanced relationship with immunocompetent individuals, which is dependent of T lymphocytes activity. We previously showed X-linked immunodeficiency (XID – B cell deficient) mice are more susceptible to encephalitozoonosis and B-1 cells presence influences in the immune response. Because XID mice are deficient both in B-1 and B-2 cells, here we investigate the role of these cells against E. cuniculi infection using cyclophosphamide (Cy) immunosuppressed murine model to exacerbate the infection. XID mice presented lethargy and severe symptoms, associated with encephalitozoonosis and there was an increase in the peritoneal populations of CD8+ and CD4+ T lymphocytes and macrophages and also in the proinflammatory cytokines IFN-γ, TNF-α and IL-6. In BALB/c mice, no clinical signs were observed and there was an increase of T lymphocytes and macrophages in the spleen, showing an effective immune response. B-2 cells transfer to XID mice resulted in reduction of symptoms and lesion area with increase of B-2 and CD4+ T populations in the spleen. B-1 cells transfer increased the peritoneal populations of B-2 cells and macrophages and also reduced the symptoms. Therefore, the immunodeficiency of B cells associated to Cy immunosuppression condition leads to disseminated and severe encephalitozoonosis in XID mice with absence of splenic immune response and ineffective local immune response, evidencing the B-1 and B-2 cells role against microsporidiosis. Author summary The adaptive immune response plays a key role against Encephalitozoon cuniculi, an opportunistic fungus for T cells immunodeficient patients. The role of B cells and antibody play in natural resistance to Encephalitozoon cuniculi remains unresolved. Previously, we demonstrated that B-1 deficient mice (XID), an important component of innate immunity, were more susceptible to encephalitozoonosis, despite the increase in the number of CD4+ and CD8+ T lymphocytes. In order to better understand the role of B-1 and B-2 cells and the relationship with the other cells of the immune response in encephalitozoonosis, we infected with E. cuniculi in cyclophosphamide immunosuppressed mice. Here we demonstrate that infected XID mice showed reduction of T cells and macrophages and increase of proinflammatory cytokines associated with disseminated and severe encephalitozoonosis with presence of abdominal effusion and lesions in multiple organs. This pattern of infection observed in mice with genetic deficiency in T cells, so we suggest that the absence of B-1 cells affects the cytotoxic capacity of these lymphocytes. When we transfer B-2 cells to XID mice, the lesion areas caused by the fungus, the populations of T lymphocytes in the peritoneum and the proinflammatory cytokines decrease, indicating a better resolution of the infection. We speculate that B-1 and B-2 cells participate in the immune response against E. cuniculi, interacting with the other components effective in immunity. The results shown here indicate that B-1 cells as a constituent of the innate response to microsporidia.

Utilização de eletroquimioterapia para carcinoma de células escamosas tegumentar em felino

A eletroquimioterapia compreende a utilizacao conjunta de farmacos antineoplasicos e aplicacao regional de pulsos eletricos (eletroporacao), maximizando a concentracao intracelular destes farmacos, assim propiciando maior acao citotoxica. A bleomicina, farmaco antimicrobiano dotado de propriedade antineoplasica, apresenta restrita penetrabilidade na membrana celular, dada a sua hidrossolubilidade. Todavia, uma vez administrada via intralesional ou intravenosa associada a eletroporacao, demonstra citotoxicidade potencializada. Foram utilizados 21 felinos acometidos por carcinoma de celulas escamosas tegumentar. Padronizou-se o protocolo eletroquimioterapico empregando-se sulfato de bleomicina, pela via intravenosa, na dose de 15U/m2 de superficie corporea. A eletroporacao foi perfilada com eletrodo composto por agulhas, pulsos eletricos com tensao de 1000 V, em onda quadrada unipolar, com duracao de 100 microsegundos, totalizando oito ciclos. Verificou-se remissao neoplasica integral em 21 felinos inclusos no estudo (100%). Inexistiram complicacoes e/ou efeitos adversos decorrentes do procedimento. O protocolo avaliado neste trabalho revelou-se exequivel, eficaz e seguro na terapeutica antineoplasica de carcinoma de celulas escamosas tegumentar felino.

Emprego do cell block de agarose como método complementar no diagnóstico citológico de tumores mamários caninos

The breast tumors are common neoplasms in several species, with high incidence in dogs. The high frequency and aggressiveness of these cases justifies the search for rapid, low cost and less invasive diagnostic methods, seeking for surgical approach and appropriate therapy. This study evaluated the appropriateness of the use of the agarose cell block technique as a diagnostic tool to complement traditional smears in the diagnosis of these processes. Therefore, it was obtained 51 samples from 30 dogs with breast tumors that underwent tumoral excision at the HOVET-UMESP, comparing the results obtained from smears, cell blocks, alone and in association (smears cell blocks-1), with the histopathologic diagnosis. The best results were obtained with the association of smears and cell block analysis, reducing the false negative results and increasing the cyto-histological correlation, reinforcing the importance of the use of cytology in routine veterinary oncology.

Microvessel density is as a prognostic factor in canine cutaneous mast cell tumors

Background Mast cell tumors represent almost 25% of canine skin neoplasms. These tumors are classified in three grades of differentiation, based on histological features. However, this grading system is a method based on subjective parameters, which generate intra- and interobserver variations. The microcirculation is an important feature to the primary tumor expansion, dissemination and metastasis, and there are essential evidences that increasing microvessel density is associated with short survival disease-free intervals. The purpose of the present study was to verify the prognostic value of the intratumoral microvessel density (IMVD) in a set of canine cutaneous mast cell tumors. Materials and methods Twenty-nine canine cutaneous mast cell tumors were subjected to immunohistochemical analysis using a rabbit polyclonal antibody anti-human von Willebrand Factor. Subsequently, the IMVD was determined by the average number of vessels in 5 low-power fields.

Utilização da classificação de Dorfman-Warnke (modificada por Burke) em patologia veterinária na avaliação da linfadenite induzida por parvovírus canino em cobaias (Cavia porcellus )

In human pathology the adequate system used to analyze and interprete reactive lymphadenopathies is based on the morphological characterization of the various areas within the lymphoid node. In veterinary pathology there is no standardization of histopathological evaluation of lymph nodes. Therefore, in this study, we applied the Dorfman-Warnke (modified by Burke) human classification of reactive lymphadenopathies to evaluate virus-induced lymphadenitis in guinea-pigs. Canine parvovirus was inoculated into the footpads of guinea-pigs and the response of popliteal lymph nodes was histologically studied. The footpads were excised after different periods of time, processed, and stained with HE, Mallory, Gordon & Sweets, Giemsa and by immunohistochemical methods. A significant increase in the weight of ipsilateral lymph nodes to the inoculation site (p<0.05) was observed. The follicular response in the lymph nodes was characterized by the reaction of the germinative center, which showed partial loss of delimitation in the mantle zone. Increased numbers of blast cells and hypertrophy of post-capillary venules were evidenced in the paracortical area of the lymph nodes. There was a discrete hyperplasia of the medullary cords and a general enlargement of the reticular net associated with those alterations. The reactional response observed was similar to viral lymphadenitis identified in humans, justifying the attempts to systematize this classification for veterinary use just like it is currently done in human medicine.