Tripanossomose em equinos na região sul do Brasil

Background:  :  :  : Trypanosoma evansi (T. evansi) is a protozoan which causes trypanosomosis in livestock in many countries of Southeast Asia, Africa and South America. Patterns of disease vary from acute epidemics with high case-fatality rates to subclinical and/or chronic disease in endemic animal populations. It is a problem of great economic importance due to the death of sick animals and high cost of treatment. This article aims to review the outbreaks of the infection by T. evansi in horses that occurred in southern Brazil. Review: These outbreaks were discussed in terms of epidemiology, clinical signs, laboratory tests, pathological findings, diagnosis and treatment by addressing the differences between the cases occurred in the state of Rio Grande do Sul and in other Brazilian states. The outbreaks due to T. evansi in livestock animals are endemic in warm-climate areas. At the Rio Grande do Sul state, most of the equine trypanosomosis occurs in the summer. This can be easily explained by the high number of bloodsucking insects, which are responsible for the mechanical transmission of the flagellate among the animals. Clinical signs such as progressive weight loss, lethargy, incoordination, instability, atrophy and paralysis of the hind limbs, difficulty in standing and walking, subcutaneous edema and abortion are often reported in T. evansi-infected equines. Anemia is the clinical alteration most observed in these infections, although its pathogenicity still remains unclear. In the present study anemia was associated with lipid peroxidation and decrease in serum iron levels and in acetylcholinesterase activity. Necropsy alterations found in the outbreaks reported in the Rio Grande do Sul state are commonly described in infections by T. evansi, except by the neurological alterations as necrotizing encephalitis of the white matter associated with edema, demyelinization and perivascular lymphoplasmocytic infiltrate. The diagnosis of the equine trypanosomosis was based on morphology and biometry of the trypomastigote forms in peripheral blood smears stained with Quick Panoptic or Giemsa methods, immunohistochemic, xenodiagnostic, and PCR T. evansi-specific. A new therapeutic protocol using diminazene aceturate at a dose of 7 mg kg-1 was tested in one of the outbreaks. This approach cured all the infected animals. Conclusion: Although T. evansi was diagnosed for the first time in Rio Grande do Sul state in 2002, veterinary clinicians have reported clinical signs such as paralysis of the pelvic members, fever and weight loss since the 80’s and 90’s. Therefore, the lack of knowledge of the disease might have been responsible for the unpublished data. Another hypothesis is the suspect of babesiosis, since both illnesses have marked anemia and hyperthermia. Moreover, as the diminazene aceturate has trypanocidal and babesicidal action, animals may have been misdiagnosed with babesiosis and may have recovered from the T. evansi infection. Only few researches on trypanosomosis are found in the southern region of Brazil. Prevalence studies with more sensible techniques are necessary in order to clarify the spread of the disease and the economic losses that it causes to farmers

Efeito do interferon beta, da ciclosporina A, do ebselen e da vitamina E no sistema colinérgico e purinérgico de ratos normais e submetidos à desmielinização pelo brometo de etídio

A esclerose múltipla é a principal doença desmielinizante do sistema nervoso central (SNC). É considerada a principal causa de incapacidade neurológica em adultos jovens. O comprometimento cognitivo é muito comum nessa doença, envolvendo o aprendizado, a memória e a organização cortical do movimento, funções vitais que são reguladas pelo sistema colinérgico. O modelo de desmielinização tóxica induzida pelo brometo de etídio (BE) foi utilizado neste estudo, para avaliar a atividade da enzima acetilcolinesterase (AChE) no estriado (ST), hipocampo (HP), córtex cerebral (CC), hipotálamo (HY) e ponte (PN) associado ao tratamento com interferon beta (IFN-b), ciclosporina A (CsA), vitamina E (vit E) e ebselen (Ebs). Além disso, também foi investigado o efeito in vitro do BE na atividade da AChE, juntamente com os parâmetros cinéticos dessa enzima no ST, HP, CC e CB de ratos adultos. Os resultados demonstraram que o BE inibiu significativamente a atividade da AChE no ST, HP, CC e CB nas concentrações de 0,00625, 0,0125, 0,025, 0,05 e 0,1mM e a análise dos dados cinéticos mostraram uma inibição do tipo incompetitiva no ST, HP e CC, enquanto no CB a inibição foi do tipo mista. No estudo in vivo, foi observado uma inibição na atividade da AChE no CC, ST, HP, HY, PN e CB nos diferentes períodos avaliados pós-injeção do BE (3, 7, 15, 21 e 30 dias). Quando ratos desmielinizados com BE foram tratados com IFN-b e CsA, não houve alteração na atividade dessa enzima. Por outro lado, o tratamento com Vit E e Ebs foram capazes de aumentar a atividade da AChE no ST, CC e HP. Estudos imuno-histoquímicos demonstraram que nos ratos tratados com Vit E e Ebs as lesões induzidas pelo BE foram menores, sugerindo que estes compostos interferem no desenvolvimento de lesões desmielinizantes. Foi também avaliado o efeito per se do IFN-b, da CsA, da Vit E e do Ebs na atividade da AChE, os quais demonstraram um efeito inibitório sobre a atividade dessa enzima. Em plaquetas de ratos desmielinizados, foi observado uma diminuição na atividade da NTPDase e o tratamento com a Vit E e o Ebs modularam a hidrólise dos nucleotídeos de adenina. O presente trabalho demonstrou que o BE é um potente inibidor da atividade da AChE in vitro e os resultados in vivo demonstraram que a atividade dessa enzima está alterada após um evento de desmielinização tóxica no SNC. Os resultados deste estudo ajudaram a confirmar que drogas utilizadas no tratamento de pacientes com esclerose múltipla tais como o IFN-b e a CsA causam efeitos na atividade da AChE. A Vit E e o Ebs, além de demonstrarem uma interação com a neurotransmissão colinérgica, também modularam a hidrólise dos nucleotídeos de adenina em plaquetas de ratos, contribuindo no controle da coagulação plaquetária em processos desmielinizantes. Neste contexto, sugere-se que o IFN-b, a CsA, a vitamina E e o ebselen podem ser investigados em estudos futuros com a intenção de encontrar uma melhor terapia para beneficiar pacientes com patologias desmielinizantes.Multiple sclerosis is the main demyelinating disease of the central nervous system (CNS). It is the most common cause of neurological disability among young adults. The cognitive impairment is very commum in this illness, involving learning, memory and cortical organization of the movement, vital functions regulated by the cholinergic system. The model of toxic demyelination induced by ethidium bromide (EB) was used to evaluate brain acetylcholinesterase (AChE) activity in the striatum (ST), hippocampus (HP), cerebral cortex (CC), cerebellum (CB), hypothalamus (HY) and pons (PN), associated with treatment with interferon beta (IFN-b), ciclosporine A (CsA), vitamin E (Vit E) and ebselen (Ebs). In addition, the per se effect of EB on AChE activity was studied in vitro together with the kinetic parameters of this enzyme in the ST, HP, CC and CB of adult rats. The results showed that EB in vitro significantly inhibited AChE activity in the ST, HP, CC and CB at concentrations of 0.00625, 0.0125, 0.025, 0.05 and 0.1mM. The kinetic analysis demonstrated an uncompetitive inhibition in the ST, HP and CC, whereas in the CB the inhibition type was mixed. In relation to the in vivo results, AChE activity was inhibited after demyelination by EB in the CC, ST, HP, HY, PN and CB at the post-injection points of time evaluated (3-7-15-21 and 30 days). When demyelinated rats were submitted to the treatment with IFN-b and CsA, the results demonstrated that these compounds did not alter AChE activity. However, Vit E and Ebs were able to increase AChE activity in the ST, CC and HP. In addition, immunohistochemistry studies demonstrated that in Vit E and Ebs treated rats, the lesions induced by EB were smaller suggesting that these compounds somehow interfered in the development of the lesions. The per se effect of IFN-b, CsA, Vit E and Ebs were also evaluated, demonstrating that these compounds have an inhibitory effect on AChE activity. Platelets of the demyelinated rats demonstrated a reduction in NTPDase activity and the treatments with Ebs and Vit E modulated adenine nucleotide hydrolysis. The present investigation demonstrated that EB is a strong inhibitor of AChE activity in vitro and the results in vivo showed that the activity of this enzyme is altered after an event of toxic demyelination in the CNS. The results this study help the confirm that drugs used in the treatment of the patients with multiple sclerosis such as IFN-b and CsA cause effects in the AChE activity. The Vit E and Ebs besides of interaction with the cholinergic neurotransmission also modulated adenine nucleotide hydrolysis in platelets of the rats, contributing to the control of the platelet coagulant status in the demyelinating process. In this context, we can suggest that IFN-b, CsA, Vit E and Ebs may be investigated in future studies with the intention of finding a better therapy for to improve patients with demyelinating pathologies

Efeito do interferon beta, da ciclosporina A, do ebselen e da vitamina E no sistema colinérgico e purinérgico de ratos normais e submetidos à desmielinização pelo brometo de etídio

A esclerose múltipla é a principal doença desmielinizante do sistema nervoso central (SNC). É considerada a principal causa de incapacidade neurológica em adultos jovens. O comprometimento cognitivo é muito comum nessa doença, envolvendo o aprendizado, a memória e a organização cortical do movimento, funções vitais que são reguladas pelo sistema colinérgico. O modelo de desmielinização tóxica induzida pelo brometo de etídio (BE) foi utilizado neste estudo, para avaliar a atividade da enzima acetilcolinesterase (AChE) no estriado (ST), hipocampo (HP), córtex cerebral (CC), hipotálamo (HY) e ponte (PN) associado ao tratamento com interferon beta (IFN-b), ciclosporina A (CsA), vitamina E (vit E) e ebselen (Ebs). Além disso, também foi investigado o efeito in vitro do BE na atividade da AChE, juntamente com os parâmetros cinéticos dessa enzima no ST, HP, CC e CB de ratos adultos. Os resultados demonstraram que o BE inibiu significativamente a atividade da AChE no ST, HP, CC e CB nas concentrações de 0,00625, 0,0125, 0,025, 0,05 e 0,1mM e a análise dos dados cinéticos mostraram uma inibição do tipo incompetitiva no ST, HP e CC, enquanto no CB a inibição foi do tipo mista. No estudo in vivo, foi observado uma inibição na atividade da AChE no CC, ST, HP, HY, PN e CB nos diferentes períodos avaliados pós-injeção do BE (3, 7, 15, 21 e 30 dias). Quando ratos desmielinizados com BE foram tratados com IFN-b e CsA, não houve alteração na atividade dessa enzima. Por outro lado, o tratamento com Vit E e Ebs foram capazes de aumentar a atividade da AChE no ST, CC e HP. Estudos imuno-histoquímicos demonstraram que nos ratos tratados com Vit E e Ebs as lesões induzidas pelo BE foram menores, sugerindo que estes compostos interferem no desenvolvimento de lesões desmielinizantes. Foi também avaliado o efeito per se do IFN-b, da CsA, da Vit E e do Ebs na atividade da AChE, os quais demonstraram um efeito inibitório sobre a atividade dessa enzima. Em plaquetas de ratos desmielinizados, foi observado uma diminuição na atividade da NTPDase e o tratamento com a Vit E e o Ebs modularam a hidrólise dos nucleotídeos de adenina. O presente trabalho demonstrou que o BE é um potente inibidor da atividade da AChE in vitro e os resultados in vivo demonstraram que a atividade dessa enzima está alterada após um evento de desmielinização tóxica no SNC. Os resultados deste estudo ajudaram a confirmar que drogas utilizadas no tratamento de pacientes com esclerose múltipla tais como o IFN-b e a CsA causam efeitos na atividade da AChE. A Vit E e o Ebs, além de demonstrarem uma interação com a neurotransmissão colinérgica, também modularam a hidrólise dos nucleotídeos de adenina em plaquetas de ratos, contribuindo no controle da coagulação plaquetária em processos desmielinizantes. Neste contexto, sugere-se que o IFN-b, a CsA, a vitamina E e o ebselen podem ser investigados em estudos futuros com a intenção de encontrar uma melhor terapia para beneficiar pacientes com patologias desmielinizantes.Multiple sclerosis is the main demyelinating disease of the central nervous system (CNS). It is the most common cause of neurological disability among young adults. The cognitive impairment is very commum in this illness, involving learning, memory and cortical organization of the movement, vital functions regulated by the cholinergic system. The model of toxic demyelination induced by ethidium bromide (EB) was used to evaluate brain acetylcholinesterase (AChE) activity in the striatum (ST), hippocampus (HP), cerebral cortex (CC), cerebellum (CB), hypothalamus (HY) and pons (PN), associated with treatment with interferon beta (IFN-b), ciclosporine A (CsA), vitamin E (Vit E) and ebselen (Ebs). In addition, the per se effect of EB on AChE activity was studied in vitro together with the kinetic parameters of this enzyme in the ST, HP, CC and CB of adult rats. The results showed that EB in vitro significantly inhibited AChE activity in the ST, HP, CC and CB at concentrations of 0.00625, 0.0125, 0.025, 0.05 and 0.1mM. The kinetic analysis demonstrated an uncompetitive inhibition in the ST, HP and CC, whereas in the CB the inhibition type was mixed. In relation to the in vivo results, AChE activity was inhibited after demyelination by EB in the CC, ST, HP, HY, PN and CB at the post-injection points of time evaluated (3-7-15-21 and 30 days). When demyelinated rats were submitted to the treatment with IFN-b and CsA, the results demonstrated that these compounds did not alter AChE activity. However, Vit E and Ebs were able to increase AChE activity in the ST, CC and HP. In addition, immunohistochemistry studies demonstrated that in Vit E and Ebs treated rats, the lesions induced by EB were smaller suggesting that these compounds somehow interfered in the development of the lesions. The per se effect of IFN-b, CsA, Vit E and Ebs were also evaluated, demonstrating that these compounds have an inhibitory effect on AChE activity. Platelets of the demyelinated rats demonstrated a reduction in NTPDase activity and the treatments with Ebs and Vit E modulated adenine nucleotide hydrolysis. The present investigation demonstrated that EB is a strong inhibitor of AChE activity in vitro and the results in vivo showed that the activity of this enzyme is altered after an event of toxic demyelination in the CNS. The results this study help the confirm that drugs used in the treatment of the patients with multiple sclerosis such as IFN-b and CsA cause effects in the AChE activity. The Vit E and Ebs besides of interaction with the cholinergic neurotransmission also modulated adenine nucleotide hydrolysis in platelets of the rats, contributing to the control of the platelet coagulant status in the demyelinating process. In this context, we can suggest that IFN-b, CsA, Vit E and Ebs may be investigated in future studies with the intention of finding a better therapy for to improve patients with demyelinating pathologies

Primary Mast Cell Tumor in the Palpebral Conjunctiva in a Dog

Background: Mastocytoma is the neoplastic proliferation of mast cells. This neoplasia exhibits a mild to extremely aggressive biological behaviour and can develop in any anatomical location. It is considered one of the most clinically relevant oncodermatological disorders in veterinary medicine, although it is considered rare in the conjunctiva of dogs. The objective of this work is to describe the case and highlight the importance of cytological examination in the diagnosis and treatment. Case: A 13-year-old mixed-breed neutered dog was brought to the Veterinary Teaching Hospital for presenting a nodule in the lower palpebral conjunctiva of the right eye for the past 3 months. The patient had good body condition and was clinically healthy. At the ophthalmic examination, a nodular and whitish enlargement with a smooth surface was observed on the lower palpebral conjunctiva of the right eye. No impairment of vision or ocular reflexes or any other alterations in the left eye were noted. Material obtained from the lesion with swab for cytological examination and stained with Diff Quick and allowed to obtain the diagnosis of mastocytoma. The cellularity was low to moderate and composed of round cells. The cytoplasm appeared indistinct with numerous metachromatic granules. The nucleus was rounded, paracentral, with condensed chromatin and inconspicuous nucleoli. Moderate anisocytosis and anisokaryosis were also observed. Complete blood count and serum biochemistry results were performed, and the results obtained were within reference values. The treatment consisted of surgical excision of the nodule with a margin of 0.5 mm on all edges followed by compressive hemostasis. The material obtained by the surgical excision was sent for histopathological analysis to confirm the cytological diagnosis and for surgical margin delimitation. On macroscopy, two eyelid fragments were identified. The tissue was firm and uniformly whitish. The smaller fragment was irregular and whitish. Microscopically, in the palpebral conjunctiva, beneath the surface epithelium, a non-circumscribed, non-encapsulated, and densely cellular infiltrative neoplastic proliferation was observed. The cells were round, with moderate amount of cytoplasm, a large number of intracytoplasmic basophilic granules, and well-defined cytoplasmic borders. The nuclei were round, with condensed chromatin and inconspicuous nucleoli. Cellular and nuclear pleomorphism was classified as moderate, and, after evaluation 10 fields at a magnification of 400x, no mitoses were seen. Toluidine blue staining improved the observation of cytoplasmic granules. Additionally, a multifocal and pronounced inflammatory infiltrate of eosinophils was noted. Histopathology findings confirmed the cytological diagnosis of mastocytoma. The patient showed good recovery after the surgical procedure with no local recurrence of the tumor after 60 days. Discussion: In clinical routine, to obtain an adequate sample for diagnosis is not always easy. The less traumatic and invasive technique should be preferred to minimize complications related to physical or chemical restraint. The time to obtain diagnostic information is also crucial for the treatment outcome. Cytological examination of a specimen obtained by swab and stained with Diff Quick staining proved to be effective for the diagnosis of a mastocytoma in the palpebral conjunctiva, a very unusual site of this tumor, demonstrating the relevance of this technique. Keywords: mast cells, cytology, histopathology, dog, oncology

Prednisona e meloxicam no tratamento de ratos submetidos ao trauma agudo da medula espinhal

O objetivo deste estudo foi investigar o efeito da prednisona e do meloxicam na terapia de ratos submetidos ao modelo experimental de trauma agudo da medula espinhal, induzida pelo cateter de Fogarty 2Fr, mediante a avaliação dos parâmetros de estresse oxidativo, dos testes neurológicos e do exame histopatológico da medula espinhal. Foram utilizados 90 ratos Wistar, distribuídos em seis grupos, denominados controle salina ou GCS (n=15), controle prednisona ou GCP (n=15), controle meloxicam ou GCM (n=15), trauma mais salina ou GTS (n=15), trauma mais prednisona ou GTP (n=15) e trauma mais meloxicam GTM (n=15). Cada grupo foi redistribuído em três subgrupos de igual número, de acordo com o tempo de tratamento no pós-operatório de 24h, 72h e sete dias. Todos os grupos foram submetidos à laminectomia e, nos grupos GTS, GTM e GTP, após a exposição da medula espinhal, foi realizado o trauma medular compressivo, utilizando o cateter de Fogarty 2Fr. Os grupos GCS e GTS foram tratados com solução salina, os GSM e GTM receberam meloxicam e os GSP e GTP prednisona, sendo administrados pela via intraperitoneal. Em todos os ratos, foram avaliados os parâmetros de estresse oxidativo, testes neurológicos e exame histopatológico da medula espinhal. Os animais dos grupos GTS, GTM e GTP, nos diferentes tempos (24h, 72h e sete dias), tiveram pontuação zero na escala de Basso, Beattie e Bresnahan (BBB); no plano inclinado, permaneceram com pontuação três e perderam a percepção da dor profunda. Os grupos GTM e GTP apresentaram menor atividade da catalase e de níveis de TBARS, quando comparado ao grupo GTS. Foi constatada degeneração Walleriana e necrose da substância cinzenta de intensidades variáveis, não apresentando diferença entre os grupos submetidos ao trauma. O meloxicam e a prednisona apresentam possível efeito antioxidante, mas não impedem a necrose e a degeneração Walleriana da medula espinhal de ratos

Aluminum-Induced Alterations in Purinergic System Parameters of BV-2 Brain Microglial Cells

Aluminum (Al) is ubiquitously present in the environment and known to be a neurotoxin for humans. The trivalent free Al anion (Al3+) can cross the blood-brain barrier (BBB), accumulate in the brain, and elicit harmful effects to the central nervous system (CNS) cells. Thus, evidence has suggested that Al increases the risk of developing neurodegenerative diseases, particularly Alzheimer’s disease (AD). Purinergic signaling has been shown to play a role in several neurological conditions as it can modulate the functioning of several cell types, such as microglial cells, the main resident immune cells of the CNS. However, Al effects on microglial cells and the role of the purinergic system remain elusive. Based on this background, this study is aimed at assessing the modulation of Al on purinergic system parameters of microglial cells. An in vitro study was performed using brain microglial cells exposed to Al chloride (AlCl3) and lipopolysaccharide (LPS) for 96 h. The uptake of Al, metabolism of nucleotides (ATP, ADP, and AMP) and nucleoside (adenosine), and the gene expression and protein density of purinoceptors were investigated. The results showed that both Al and LPS increased the breakdown of adenosine, whereas they decreased nucleotide hydrolysis. Furthermore, the findings revealed that both Al and LPS triggered an increase in gene expression and protein density of P2X7R and A2AR receptors, whereas reduced the A1R receptor expression and density. Taken together, the results showed that Al and LPS altered the setup of the purinergic system of microglial cells. Thus, this study provides new insights into the involvement of the purinergic system in the mechanisms underlying Al toxicity in microglial cells