Academic literature on the topic 'Diminazeno'

RESUMO: Aceturato de diminazeno é um fármaco quimioterápico sintético comumente usado na medicina veterinária para o tratamento de doenças causadas por parasitos hematozoários. Entretanto, seu uso pode levar a efeitos colaterais, como alterações neurológicas graves e morte. A criação de camelídeos é uma atividade recente no Brasil, fazendo-se necessário conhecer mais sobre as doenças que acometem essas espécies. De dez camelídeos (seis lhamas e quatro alpacas) da propriedade, seis tiveram sinais clínicos e, destes, apenas uma lhama com manifestações leves recuperou-se. Os sinais clínicos incluíam apatia, andar cambaleante, fraqueza, sialorreia, cabeça baixa e pendida lateralmente, dificuldade em levantar e dispneia, observados a partir de 18 horas após o uso do medicamento. À necropsia e ao exame histopatológico foram observadas alterações de encefalopatia hemorrágica bilateral e simétrica, mais graves em tronco encefálico e tálamo. Este trabalho descreve as principais lesões observadas em um surto de intoxicação por diminazeno em alpacas (Lama pacos) e lhamas (Lama glama) e alerta criadores e veterinários sobre o risco de intoxicação por aceturato de diminazeno em camelídeos sul americanos.

Este estudo teve como objetivo avaliar o efeito do aceturato de diminazeno e do dipropionato de imidocarb no controle da infecção por Trypanosoma evansi em ratos (Rattus norvegicus) infectados experimentalmente. Cinqüenta e quatro ratos machos foram inoculados via intraperitonial com 104 tripomastigotas de T. evansi/animal. Os ratos foram monitorados diariamente por meio de esfregaço sanguíneo periférico. No momento em que se observassem oito protozoários por campo microscópico de 1000x, era iniciado o tratamento com as drogas (dia zero). O estudo foi dividido em dois protocolos terapêuticos e os fármacos foram administrados via intramuscular. O primeiro protocolo foi aplicado nos grupos A, B, C e D e o segundo protocolo nos grupos E, F, G e H. O grupo controle foi identificado como grupo I, não medicados. No primeiro protocolo, os ratos receberam uma dose única dos fármacos no dia zero e sempre que se observasse T. evansi na circulação periférica. No segundo protocolo, os roedores receberam as mesmas doses, no entanto, por cinco dias consecutivos. No primeiro protocolo, os dois princípios ativos não apresentaram eficácia curativa, ocorrendo reincidência da parasitemia após alguns dias do tratamento. No segundo protocolo, o aceturato de diminazeno eliminou a forma tripomastigota da circulação e os ratos foram eutanasiados após 90 dias do início do tratamento. Os roedores tratados com dipropionato de imidocarb apresentaram recidiva da infecção após 30 dias. Na histopatologia não se observou alteração renal e hepática relacionada à doença ou aos medicamentos testados. Com base nos resultados, foi concluído que o aceturato de diminazeno, quando administrado por cinco dias consecutivos, é efetivo no tratamento da tripanossomose em ratos.

Os aspectos epidemiológicos, clínicos e anatomopatológicos da intoxicação espontânea por aceturato de diminazeno foram estudados em 10 cães. Em todos os casos, os cães afetados demonstraram sinais de síndrome tálamo-cortical, principalmente alteração do nível de consciência, tetraparesia, rigidez extensora e crise convulsiva. Em alguns casos, os cães acometidos apresentaram sinais de síndrome cerebelar, como tremores musculares generalizados de alta frequência e baixa amplitude, e/ou de síndrome vestibular, como ataxia, inclinação de cabeça e quedas. Esses sinais ocorreram entre 24 e 48 horas após o uso do fármaco injetável por via intramuscular e se mantiveram até a morte ou eutanásia dos cães (entre 1 e 7 dias). Tais sinais clínicos refletiam encefalomalacia hemorrágica focal simétrica, que afetava a medula oblonga, a ponte, a medular do cerebelo, o tálamo, o mesencéfalo, os pedúnculos cerebelares e os núcleos da base. Esse artigo: 1) descreve e discute essa forma de intoxicação medicamentosa tão pouco citada na literatura internacional e desconhecida da maior parte dos clínicos e patologistas veterinários brasileiros, 2) estabelece critérios clínicos e anatomopatológicos para o seu diagnóstico e, principalmente, 3) atenta para os riscos da utilização desse princípio ativo na terapêutica canina.

ABSTRACT Resistance to diminazene aceturate (Berenil) is a severe problem in the control of African trypanosomiasis in domestic animals. It has been speculated that resistance may be the result of reduced diminazene uptake by the parasite. We describe here the mechanisms by which [3H]diminazene is transported by Trypanosoma brucei brucei bloodstream forms. Diminazene was rapidly accumulated through a single transporter, with a Km of 0.45 ± 0.11 μM, which was dose dependently inhibited by pentamidine and adenosine. The Ki values for these inhibitors were consistent with this transporter being the P2/TbAT1 adenosine transporter. Yeast expressing TbAT1 acquired the ability to take up [3H]diminazene and [3H]pentamidine. TbAT1-null mutants had lost almost all capacity for [3H]diminazene transport. However, this cell line still displayed a small but detectable rate of [3H]diminazene accumulation, in a nonsaturable manner. We conclude that TbAT1 mediates [3H]diminazene transport almost exclusively and that this explains the observed diminazene resistance phenotypes of TbAT1-null mutants and field isolates.

Trypanosomosis is a major cause of mortality for dogs in Nigeria and treatment with diminazene aceturate has steadily become less effective, either as a result of low quality of the locally available diminazene preparations or of drug resistance. To investigate these alternatives, samples of locally obtained drugs were analysed for diminazene aceturate content and a strain of Trypanosoma brucei brucei was isolated from a diminazene-refractory dog in Nsukka, south-eastern Nigeria, and used to infect albino rats. The quality of diminazene aceturate-based preparations was variable, with two preparations containing less than 95% of the stated active compound. Rats infected with T. brucei isolated from the dog were treated 7 and 10 days after infection either with 7 mg/kg diminazene aceturate (intraperitoneally, once) or with 4 mg/kg pentamidine isethionate (intramuscularly, 7 consecutive days). Relapse rates were 100% for both trypanocides in the groups of rat treated 10 days post-infection, and 83% and 50% of rats treated 7 days after infection relapsed to diminazene aceturate and pentamidine isethionate, respectively. Careful consideration of physiological parameters showed that pentamidine was only marginally superior to diminazene aceturate as applied in this study. It was concluded that dogs in Nigeria are infected with genuinely diminazene aceturate-resistant trypanosomes that appear to be cross-resistant to pentamidine isethionate.

Relapse parasitaemia is a major setback in the chemotherapy of a late stage Trypanosoma brucei brucei infection. An aberrant serum biochemical profile resulting from a T. b. brucei infection in dogs has been attributed to multiple organ injuries resulting from the invasive nature of the organism. Therapy with diminazene aceturate alone has not been satisfactory. This study evaluated the effects of a secnidazole-diminazine aceturate (SEC-DA) combination therapy on parasitaemia and the serum biochemical profile after the late treatment of a T. b. brucei infection in dogs. Eighteen dogs were randomly assigned to 6 groups (n = 3) as follows: Group A: uninfected nor treated; group B: infected without treatment; group C: infected and treated with DA (3.5 mg/kg) (DA-monotherapy) intramuscularly (i.m.) once; group D: infected and treated with SEC (100 mg/kg) and DA (3.5 mg/kg); group E: in-fected and treated with SEC (200 mg/kg) and DA (3.5 mg/kg) and group F: infected and treated with SEC (400 mg/kg) and DA (3.5 mg/kg). Secnidazole was administered orally for 5 days while DA was given i.m. once in groups D–F. The dogs were infected with 5 × 10⁵ trypanosomes intraperitoneally and treatment started 14 days post-infection. The parasitaemia was monitored daily while the serum biochemical indicators were monitored 14, 21, and 28 days post-infection. The total aparasitaemia was achieved in the SEC-DA treated dogs 72 h post-treatment and in 86 h in the DA-monotherapy dogs. A relapse parasitaemia occurred in the DA-monotherapy dogs 17 days post-treatment. The SEC-DA combination therapy caused a significant (P < 0.05) decline in the hitherto elevated urea and creatinine concentrations, and the ALP, ALT, AST activities. Also, there was a significant (P < 0.05) increase in the previously decreased serum albumin in the SEC-DA treated dogs. In conclusion, secnidazole-diminazene aceturate combination therapy prevented the relapse parasitaemia and ameliorated aberrant serum biochemical profiles of T. b. brucei infected dogs after late treatment.

Abstract Background: This study was carried out to determine the blood pressure changes in experimentally Trypanosoma brucei brucei-infected Wistar albino rats and diminazene aceturate-treated rats. Methods: Twenty-four rats were purchased and divided into four groups consisting of six rats each. Control group (CON) received 0.5 mL of distilled water, i.m., infected but not treated group (INF) received 2×106 trypanosome/mL i.m., infected but diminazene aceturate-treated group (INFDIM) received 2×106 trypanosome/mL, 3.5 mg/kg, i.m.) and non-infected but diminazene aceturate-treated group (DIM) received 3.5 mg/kg, i.m. and served as negative control. The blood pressures were measured using a CODA 2® non-invasive blood pressure monitor (Kent Scientific, USA). The results were compiled and statistical analysis was done with significance set at p≥0.05. Results: The values of the blood pressure readings of the Trypanosoma-infected INF (137.0±2.0 mmHg) and diminazene-treated rats INFDIM (125.0±7.5 mmHg) when compared to the control group (168.0±3.0 mmHg) were significantly lower (p≤0.05) at the end of day 7. The heart rate was also significantly reduced in the INF (403.5±1.5 beats/min) and DIM (445.0±24 beats/min) groups of rats when compared with the control group (613.0±2.0 beats/min) at the end of day 8. Conclusion: The findings indicate the significant reduction in blood pressure and heart rates during Trypanosoma brucei brucei infection and with diminazene aceturate administration. Hence, caution should be exercised when treating trypanosome-infected patients with diminazene aceturate.

This work presents UV first derivative spectrophotometry as a precise, accurate, and feasible method for simultaneous determination of diminazene diaceturate and phenazone in bulk and dosage forms. The absorbance values of diminazene diaceturate and phenazone aqueous mixture were obtained at 398 nm and 273 nm, respectively. The developed method was proved to be linear over the concentration ranges (2–10) μg/mL and (2.496–12.48) μg/mL for diminazene diaceturate and phenazone, respectively, with good correlation coefficients (not less than 0.997). The detection and quantitation limits were found to be (LOD = 0.63 and 0.48 μg/mL; LOQ = 1.92 and 1.47 μg/mL, resp.). The developed method was employed for stability studies of both drugs under different stress conditions. Diminazene diaceturate was prone to degrade at acidic pH via first-order kinetics. The degradation process was found to be temperature dependent with an activation energy of 7.48 kcal/mole. Photo-stability was also investigated for this drug.

This paper aimed to describe some lab and histological findings from an experimental infection of Trypanosoma (Trypanozoon) evansi Steel, 1885 (Balbiani, 1888) in rats (Rattus novergicus) belonging to the Wistar strain, testing the effectiveness of three medications. These animals were divided in 4 groups of 10 each and treated to three different chemical treatments after the detection of more than eight tripomastigotes for visual side of the blood smears at the light microscope with 1000 increase. Was tested injectable oxytetracycline 10%, benzonidazol per oss and injectable diminazene 7% while one infected and untreated group remained as control. Evaluation of treatment efficacy was performed through daily blood smears stained by Panotico Rápido® for 60 days. The rats were necropsied aiming histological examination. Treatment with diminazene was the most efficient since no parasites having significant difference (p < 0.05) between males and females of that group, which presented survive after the treatment of 14,4 days more than the males. Histological alterations findings were not specific.
Este trabalho objetivou verificar os achados laboratoriais e histológicos da infecção experimental por Trypanosoma (Trypanozoon) evansi (Steel, 1885) Balbiani, 1888, em ratos (Rattus norvegicus) da linhagem Wistar, testando a eficácia de três medicamentos. Foram utilizados 40 ratos, divididos em quatro grupos de 10 cada, sendo cada grupo composto por 5 machos e cinco fêmeas, os quais foram tratados com três quimioterápicos distintos após a detecção de parasitemia superior a oito tripomastigotas por campo visual do esfregaço sangüíneo ao microscópio de luz (1000 vezes). Testou-se oxitetraciclina 10% injetável, benzonidazol comprimidos de 100mg e aceturato de diminazeno 7% injetável comparados com um grupo controle, experimentalmente infectado, mas não tratado. As avaliações foram feitas por contagens diárias da presença de hemoparasitas em esfregaço sangüíneo, corado por Panótico Rápido®, por 60 dias. Os ratos foram necropsiados e avaliados histologicamente à procura de alterações microscópicas dos órgãos afetados. O tratamento feito com aceturato de diminazeno foi o mais eficaz no controle da parasitemia, havendo diferença significativa (p < 0.05) entre machos e fêmeas desse grupo, as quais apresentaram período de sobrevida após o tratamento de 14,4 dias superior aos machos. Histologicamente as alterações encontradas nos órgãos afetados foram inespecíficas.

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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
Activation of the Angiotensin Converting Enzyme 2 (ACE2)-Angiotensin-(1-7) [Ang(1-7)]-Mas Receptor axis results in protective effects in the cardiovascular system. ACE 2 is an important component of Renin-Angiotensin System, because it is able to convert Angiotensin II in Ang-(1-7). Recents studies have shown that diminazene aceturate (DIZE) act as an activator of ACE 2. The objective of this study was to evaluate the cardiovascular effects of chronic treatment with DIZE in pressureoverloaded rats and the possible mechanisms involved in these effects. Male Wistar rats (200-350 g) were divided in four groups: (1) Sham; (2) Coarcted (abdominal aortic banding, CAA); (3) CAA + DIZE (1 mg/kg, gavage); e (4) CAA + DIZE (1 mg/kg, gavage) + A-779 (120 µg/day, osmotic mini-pumps). Twenty one days after surgery procedure, the blood pressure was recorded, the hearts were isolated and perfused according to Langendorff method. Vascular reactivity was measured by isolated aortic ring preparation. In order to evaluate the cardiac hypertrophy, the left ventricular mass index (VMI) was calculated through the ratio of the left ventricular wet weight to tibia length. The cross-sectional area of cardiomyocytes (CSA) was also evaluated. The mRNA levels for ANP, BNP e TGF-β were also evaluated by qRT-PCR. The expression of ACE-2 and ERK1/2, AKT, mTOR, GATA-4, catalase and SOD proteins involved in hypertrophic pathways was analyzed by Western Blot technique. The results are presented as means ± SEM. One-way ANOVA followed by the Newman-Keuls post-test was used to analyze the blood pressure, cardiac morphometric parameters, isolated heart, qRT-PCR and Western Blot experiments. Two-way ANOVA followed by the Bonferroni post-test was used for aortic rings preparation protocols. All statistical analyses were considered significant at P<0.05. Isolated hearts from coarcted rats presented a significant decrease in the left ventricular end systolic pressure (128.1 ± 9.0 vs. 79.1 ± 12.8 mmHg in CAA, P<0.05), left ventricular developed pressure (118.1 ± 8.9 vs. 69.0 ± 12.7 mmHg in CAA, P<0.05), +dP/dt (2295.0 ± 161.8 vs. 1406.0 ± 246.5 mmHg/s in CAA, P<0.05) and dP/dt (1787.0 ± 166.0 vs. 1066.0 ± 181.9 mmHg/s in CAA, P<0.05). The DIZE treatment attenuated all of these effects induced by CAA. Moreover, DIZE treatment increased the coronary flow in hypertrophic hearts (CAA: 11.6 ± 0.8 vs. CAA+DIZE: 15.8 ± 0.6 mL/min, P<0.05). This effect was blocked by A-779. Pressure–overloaded hearts showed a significant increase in VMI (0.17 ± 0.01 vs. 0.21 ± 0.01 g/cm in CAA, P<0.05) and CSA (8.98 ± 0.54 vs. 10.72 ± 0.27 µm in CAA, P<0.05). The chronic treatment with DIZE prevented the heart hypertrophy (10.72 ± 0.27 in CAA vs. 9.25 ± 0.23 µm in CAA+DIZE, P<0.05). Indeed, treatment with A-779 attenuated the antihypertrophic effect induced by DIZE treatment. The coarcted rats presented a increase in mRNA expression of ANP, BNP and TGF-β and the DIZE treatment reverted this effect. The pressure overload decreased the acetylcholine-induced relaxation in aortic rings from coarcted rats and treatment with DIZE was not able to improve this effect. The coarctation decreased the phosphorylation of the AKT, which was not changed by DIZE treatment. The expression of ACE 2, total and phosphorylated ERK1/2, total AKT, mTOR, SOD and catalase was not changed by coarctation or by ACE 2 activation. These results show that the chronic treatment with DIZE was efficient in preventing the left ventricular hypertrophy and cardiac dysfunction induced by pressure overload. These effects were independent of changes in the expression of ACE 2, ERK1/2, AKT, mTOR, SOD and catalase. Thus, DIZE has important therapeutic potential for cardiovascular diseases.
A ativação do eixo Enzima Conversora de Angiotensina 2 (ECA2)-Angiotensina-(1-7) [Ang-(1-7)]-Receptor Mas resulta em importantes efeitos protetores no sistema cardiovascular..A ECA 2 é um importante componente do Sistema ReninaAngiotensina, pois hidrolisa a Angiotensina II em Ang-(1-7). Recentes estudos tem demonstrado que o aceturato de diminazeno (DIZE) apresenta capacidade de aumentar a atividade da ECA 2. Sendo assim, o objetivo deste estudo foi avaliar os efeitos cardiovasculares do DIZE nas mudanças induzidas por sobrecarga pressórica e possíveis mecanismos intracelulares envolvidos nestes efeitos. Foram utilizados ratos Wistar (200-350 g), divididos em quatro grupos: (1) Sham; (2) Coarctados (coarctação da aorta abdominal, CAA), (3) CAA + DIZE (1 mg/kg, gavagem); e (4) CAA + DIZE (1 mg/kg, gavagem) + A-779 (120 µg/dia, mini-bombas osmóticas). Decorridos 21 dias da coarctação, a pressão arterial dos animais foi registrada, os corações foram isolados e perfundidos pelo método de Langendorff com pressão constante. A reatividade vascular foi avaliada por preparação de anéis de aorta isolada. Para avaliar a hipertrofia cardíaca, o peso dos ventrículos esquerdos foi normalizado pelo comprimento das tíbias e expresso como índice de massa ventricular (IMV), além da área de secção transversa dos cardiomiócitos (AST) ser também medida. Os níveis de mRNA para ANP, BNP e TGF-β também foram avaliados por qRT-PCR. A expressão de ECA 2 e das proteínas ERK1/2, AKT, mTOR, GATA-4, SOD e catalase, envolvidas em vias pró-hipertróficas, foi analisada através da técnica de Western Blot. Os resultados foram apresentados como média ± erro padrão da média. Para as análises de pressão arterial média, coração isolado e parâmetros morfométricos, qRT-PCR e Western Blot, foi utilizado o teste ANOVA One Way seguido pelo pós-teste de Newman-Keuls. Para a reparação de anéis de aorta isolada, foi usado ANOVA Two Way seguido pelo teste de Bonferroni. As diferenças foram consideradas significativas com P<0,05. Os corações isolados dos ratos coarctados apresentaram diminuição significativa da pressão ventricular esquerda ao final da sístole (128,1 ± 9,0 vs. 79,1 ± 12,8 mmHg em CAA, P<0,05), pressão desenvolvida pelo ventrículo esquerdo (118,1 ± 8,9 vs. 69,0 ± 12,7 mmHgem CAA, P<0,05), +dP/dt (2295,0 ± 161,8 vs. 1406,0 ± 246,5 mmHg/s em CAA, P<0,05) e -dP/dt (1787,0 ± 166,0 vs. 1066,0 ± 181,9 mmHg/s em CAA, P<0,05). A ativação da ECA 2 atenuou a disfunção ventricular esquerda induzida pela coarctação. O tratamento com DIZE aumentou o fluxo coronariano dos corações hipertrofiados (CAA: 11,6 ± 0,8 vs. CAA+DIZE: 15,8 ± 0,6 mL/min, P<0,05). Este efeito foi loqueado pelo A-779. Os corações submetidos a sobrecarga pressórica mostraram um umento significativo do IMV (0,17 ± 0,01 vs. 0,21 ± 0,01 g/cm em CAA, P<0,05) e AST (9,37 ± 0,55 vs. 10,72 ± 0,27 µm em CAA, P<0,05). A ativação da ECA 2 preveniu a hipertrofia cardíaca (AST: 10,72 ± 0,27 vs. 9,25 ± 0,23 µm em CAA + DIZE, P<0,05). O tratamento com A-779 atenuou o efeito anti-hipertrófico produzido pelo DIZE nos corações coarctados. A coarctação também promoveu aumento da expressão de mRNA de ANP, BNP e TGF-β e o tratamento com DIZE reverteu esse efeito. A sobrecarga pressórica diminuiu o relaxamento induzido por acetilcolina em anéis de aorta isolada e o tratamento com o ativador da ECA 2 não foi capaz de alterar esse efeito. A coarctação diminuiu a fosforilação da AKT e o tratamento com DIZE não foi capaz de alterá-la. Não foram encontradas alterações na expressão das proteínas ECA 2, ERK1/2 total e fosforilada, AKT total, mTOR, GATA-4, SOD e catalase. Tais resultados mostram que o tratamento crônico com DIZE apresenta efeitos cardioprotetores contra a disfunção cardíaca induzida pela sobrecarga pressórica através da diminuição da hipertrofia ventricular esquerda, sem mudanças na expressão de ECA 2, ERK1/2, AKT, mTOR, GATA-4, SOD e catalase. Portanto, o DIZE possui importante potencial terapêutico frente a doenças cardiovasculares.

Conselho Nacional de Desenvolvimento Científico e Tecnológico
The aim of this study was to evaluate the utilization of a standard treatment with diminazene aceturate against the infection caused by T. evansi, associated to sodium selenite and vitamin E. In vitro tests showed trypanocidal effect related to the treatment with diminazene aceturate and sodium selenite, but vitamin E had no harmful effect on the trypanosomes. In vivo experiments utilized a total of 72 adult outbreed females rats, separated into 9 groups (A, B, C, D, E, F, G, H and I), 8 animals each. Group A was the uninfected group; groups B to I were infected with 0.2 mL of blood containing 106 trypanosomes. Parasitemia was estimated daily by microscopic examination of blood smears. Group B served as positive control; group C was treated with diminazene aceturate; group D with sodium selenite; group E with vitamin E; group F received an association of diminazene aceturate and sodium selenite; group G received an association of diminazene aceturate and vitamin E; group H received an association of diminazene aceturate, sodium selenite and vitamin E, and group I received an association of sodium selenite and vitamin E. Diminazene aceturate was administrated in a single dose on the 3rd day post infection (PI). Sodium selenite and vitamin E were administered at the 3rd and 23rd day PI. In vivo tests showed increase of longevity in groups treated with diminazene aceturate associated with sodium selenite (groups F and H). No difference was found between groups C and E, thus the vitamin E did not increase the efficacy of treatment against T. evansi when associated to diminazene aceturate. The curative efficacy of treatments was 37.5, 87.7, 37.7 and 75% to the groups C, F, G and H, respectively. Other treatments showed no efficacy. The sodium selenite when combined with chemotherapy may represent an alternative in the treatment of trypanosomosis.
O objetivo deste estudo foi avaliar a utilização de um tratamento padrão contra a infecção causada pelo T. evansi, baseado na utilização do aceturato de diminazeno associado ao selenito de sódio e a vitamina E. Os testes in vitro mostraram um efeito tripanocida relacionados ao tratamento com aceturato de diminazeno e selenito de sódio; contudo a vitamina E não gerou nenhum efeito nocivo sobre o tripanossomas. Experimentos in vivo utilizaram um total de 72 fêmeas adultas de ratos, separados em 9 grupos (A, B, C, D, E, F, G, H e I), com 8 animais cada grupo. O grupo A serviu como grupo não infectado; grupos de B a I foram infectados com 0,2 mL de sangue contendo 106 tripanossomas. A parasitemia foi estimada diariamente por exame microscópico de esfregaços sanguíneo. O grupo B serviu como controle positivo; grupo C, tratado com aceturato de diminazeno; grupo D, com selenito de sódio; grupo E, com vitamina E; grupo F, recebeu uma associação de aceturato de diminazeno e selenito de sódio; grupo G, associação de aceturato de diminazeno e vitamina E; grupo H, associação de aceturato de diminazeno, selenito de sódio e vitamina E; e por fim o grupo I o qual recebeu uma associação de selenito de sódio e vitamina E. O aceturato de diminazeno foi administrado em dose única no 3º dia pós-infecção (PI). Selenito de sódio e vitamina E foram administradas no 3º e 23º dias PI. Os testes in vivo mostraram aumento da longevidade nos grupos tratados com aceturato de diminazeno associado ao selenito de sódio (grupos F e H). Não foi encontrada diferença entre os grupos C e E, portanto, a vitamina E não aumentou a eficácia do tratamento contra T. evansi quando associado ao aceturato de diminazeno. A eficácia curativa dos tratamentos foi de 37.5, 87.7, 37.7 e 75% para os grupos C, F, G e H, respectivamente. Os demais tratamentos não mostraram eficácia. Assim, podemos sugerir que o selenito de sódio, quando combinado com a quimioterapia pode representar uma alternativa no tratamento da tripanossomose.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The aim of this study was to develop and to evaluate the therapeutic efficacy of liposomes diminazene aceturate and in vitro and by using mice experimentally infected with Trypanosoma evansi. In vitro tests were performed in culture medium at concentrations of 0.25, 0.5, 1, 2 and 3 mg/ml of diminazene aceturate convetional (CDMZ) and liposomal (L-DMZ). A total of 114 rats (Rattus norvegicus) were used of in vivo test. These rats were divided into 6 groups (A, B, C, D, E and F). Group A served as a negative control (uninfected and untreated). Rats in Group B served as a positive control and were infected with T. evansi. Animals in Group C were infected and treated with L-DMZ (single dose, 3.5 mg/kg-1), Group D was composed with infected and treated with C-DMZ animals (single dose, 3.5 mg/kg-1), Group E infected treated with L-DMZ animals for 5 consecutive days (3.5 mg/kg-1/dia) and Group F infected treated with C-DMZ animals for 5 consecutive days (3.5 mg/kg-1/dia). In vitro, a dose-dependent trypanocidal effect of L-DMZ was observed against the parasite. In vivo, the efficacy of L-DMZ and C-DMZ in different therapeutic protocols was similar. The analysis of biochemical and histological parameters on the 7th and 40th post-treatment revealed alterations in liver and kidney enzymes, and histological alterations in the structure of organs, especially in the animals treated with L-DMZ at 5 consecutive days. The results of this study showed that liposomal formulations may be a new alternative for the treatment of tripanosomoses, but future research could be undertaken to improve the conduction of liposomes and direction for greater efficiency.
Este estudo teve como objetivo desenvolver e testar lipossomas de aceturato de diminazeno em testes in vitro e in vivo visando o controle de Trypanosoma evansi. O teste in vitro foi realizado em meio de cultura nas concentrações de 0,25, 0,5, 1, 2 e 3 μg/mL de aceturato de diminazeno convencional (C-DMZ) e lipossomal (L-DMZ). Para os testes in vivo foram utilizados 114 ratos (Rattus norvegicus) divididos em seis grupos (A, B, C, D, E e F) em dois experimentos, um para avaliar a eficácia e outro para analisar os parâmetros bioquímicos e histológicos. O grupo A foi utilizado como controle (animais sadios), B (animais infectados e não tratados), C (animais infectados e tratados com aceturato de diminazeno lipossomal com dose única 3,5 mg/kg-1), D (animais infectados e tratados com aceturato de diminazeno convencional com dose única 3,5 mg/kg-1), E (animais infectados e tratados com aceturato lipossomal por 5 dias consecutivos com a dose de 3,5 mg/kg-1/dia) e grupo F (animais e infectados tratados com aceturato convencional por 5 dias consecutivos com a dose de 3,5 mg/kg-1/dia). O teste in vitro com o lipossoma de aceturato de diminazeno mostrou uma maior mortalidade dose-dependente do T. evansi em meio de cultura se comparado ao medicamento comercial e os parasitos morreram mais rapidamente que nos grupos de aceturato de diminazeno convencional e controle. Nos resultados dos testes in vivo, a eficácia do aceturato de diminazeno lipossomal e convencional nos diferentes protocolos terapêuticos foram similares. A análise dos parâmetros bioquímicos e histológicos realizados no 7º e 40º pós-tratamento revelaram alterações nas enzimas hepáticas e renais, além de modificações na estrutura dos órgãos, principalmente nos animais tratados com lipossomas na maior dosagem. Os resultados obtidos neste estudo demonstraram que as formulações lipossomais podem ser uma nova alternativa para o tratamento das tripanossomoses. Futuras pesquisas poderiam ser realizadas para melhorar o carreamento e a direção dos lipossomas para uma maior eficácia.

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O Aceturato de Diminazeno (DIZE) é utilizado como medicamento anti- trypanosomal de uso veterinário que é capaz de aumentar a velocidade catalítica da enzima conversora de angiotensina- 2 (ECA-2). Portanto, o objetivo do nosso trabalho foi investigar os efeitos do tratamento com DIZE no remodelamento cardíaco após infarto agudo do miocárdio (IAM). Além disso, a proposta foi comparar os dados do tratamento com DIZE com modelo experimental tratado com Losartan (Los). Ratos Wistar Macho foram submetidos ao procedimento cirúrgico de oclusão permanente da artéria coronária esquerda para produzir IAM, os animais controles foram submetidos ao mesmo procedimento cirúrgico, porém sem a oclusão arterial. Após a cirurgia os animais foram distribuídos em cinco grupos: (1) Ratos Controles + Placebo (Con-Pla; n= 8); (2) Ratos Controles + DIZE (Con-DIZE; n= 6); (3) Ratos Infartados + Placebo (IM-Pla; n= 7); (4) Ratos Infartados + DIZE (IM-DIZE; n= 6); (5) Ratos Infartados + Losartan (IM-Los; n= 7), foram administrados diariamente injeção subcutânea de 15 mg/kg (DIZE e/ou Los) e placebo (NaCl 0.9%), durante 28 dias. Após 28 dias os animais foram anestesiados para obter as variáveis hemodinâmicas intracardíaca. Após registro hemodinâmico o coração foi parado em diástole com uma injeção intravenosa de KC1 (1M). Um cateter de duplo lúmen foi inserido dentro da cavidade do ventrículo esquerdo (VE) para obter os dados da curva pressão volume. Os Corações foram fixados em paraformol e processados para análise histológica de hipertrofia dos miócitos e conteúdo de colágeno. O grupo IM-Pla apresentou aumento significativo da pressão diastólica final do ventrículo esquerdo (26±3,3 mmHg) e redução na dp/dt+ (3014 ± 161 mmHg/s) e dpdt- ( -2333±91 mmHg/s) e pressão sistólica do VE (101±3,1 mmHg), quando comparados com os grupos tratados com DIZE (PDFVE: 15±1,6 mmHg/s; dp/dt+ 3884±104 mmHg/s; dpdt-: -2798±120 e PSVE: 110±0,7 mmHg) e IM-Los (PDFVE: 16±2,9; dp/dt+: 4146±131 mmHg/s; dpdt-: 2823±136 mmHg/s e PSVE: 111±3,5 mmHg). A hemodinâmica do ventrículo direito (VD) mostrou aumento de pressão do VD no grupo IM-Pla (40±0,6 mmHg) e redução da pressão no grupo IM-DIZE (37±2 mmHg). Os grupos de IM-DIZE (0,33±0,03 mmHg/mL e 0,64±0,01 mmHg/mL) e IM-Los (0,36±0,03 mmHg/mL e 0,65±0,04 mmHg/mL) apresentaram menor dilatação e rigidez no ventrículo esquerdo, quando comparados com com o grupo infartados sobre Pla (0,39±0,03 mmHg/mL e 0,78±0,02 mmHg/mL). O aumento da fração volumétrica de colágeno no VE foi parcialmente prevenido pelo tratamendo com DIZE ou Los. A hipertrofia dos miocitos pós-infarto permaneceu inalterado pelo tratamento com DIZE. Como esperado o tratamento com losartan atenuou o crescimento hipertrófico no ventriclo esquerdo quando comparado aos grupos controles. Em conclusão, nosso estudo apresentou que o DIZE foi parcialmente eficaz para prevenção de mudanças hemodinâmicas induzidas por infarto em ratos semelhante à observação em ratos infartados tratados com Los. As duas drogas também previnem o aumento da deposição de colágeno no miocárdio do ventrículo esquerdo. Em relação a hipertrofia dos miocitos, porém, apenas Los apresentou um efeito preventivo. Palavras Chaves Infarto do miocárdio, ECA-2, Diminazeno, Losartan, Insuficiência Cardíaca

Diminazene is the therapy of choice for canine babesiosis in South Africa. Differences in the dosage described for diminazene usage and the occurrence of mortality at doses equal to or close to the recommended treatment dose for the treatment of canine babesiosis have been described. This has necessitated the need to more fully understand the absorption and disposition of diminazene in dogs. An intravenous (i.v.) as well as an intramuscular (i.m.) pharmacokinetic study was conducted to determine the pharmacokinetics of diminazine in healthy dogs as well as to describe the binding characteristics of diminazine (in the blood) in vivo and in vitro. Diminazene pharmacokinetics showed a large inter-individual variation after i.m. administration at 4.2 mg/kg (% CV 37 – 163) with a rapid absorption (K01-Hl - 6.6 + 10.8 min resulting in a Cmax of 1849 + 268.7 ng/ml at Tmax of 20 min. There was a rapid distribution phase (T½a 21.6 + 11.4 min) with the distribution into the peripheral compartment being more rapid than the distribution back in to the central compartment. A mean elimination half-life (T½b 5.31 + 3.89 h) was derived. At 1 h after i.m. injection, 75 % of the diminazene in whole blood was in the plasma fraction. Compartmental analysis of the i.v. data after diminazene administration at 2 mg/kg revealed a Cmax of 3725 + 1672.8 ng/ml with a rapid distribution phase (T½a 7.0 + 6.2 min) with a long elimination half-life (T½b - 32.0 ± 28.8 h). The distribution into the peripheral compartment was more rapid than the distribution back into the central compartment as measured by K12 and K21 (K12 - 8.78 + 8.71; K21 0.32 + 0.25). The i.v. pharmacokinetic results were very variable between the dogs with a % CV of 55.5 – 137.2. We hypothesize that the rapid distribution phase is a result of diminazene being sequestered into the liver, followed by a slow terminal phase were diminazene is both redistributed to the peripheral tissues and renally excreted. The T½b of 32.0 ± 28.8 h in the i.v. study is considerably longer than the elimination half-life (T½b - 5.31 + 3.89 h) found in the i.m. study. This is most likely due the 25 ng/ml limit of detection of the HPLC, detecting the i.v. tail but not the i.m. tail. This is not surprising as the Cmax levels following i.v administration were more than 2 times higher than after i.m. administration. Further pharmacokinetic studies with diminazene in dogs should take account of the rapid absorption of diminazene after i.m. administration and the low levels of diminazene in the terminal phases. The initial sequestration of diminazene in the liver and distribution to the peripheral compartment needs further clarification. With the knowledge gained of the pharmacokinetics of diminazene in healthy dogs, a population pharmacokinetic study in dogs with babesiosis is recommended. This will allow us to more fully appreciate alterations in the pharmacokinetics of diminazene in diseased populations and the potential covariants exerting an effect. It is our current recommendation that diminazene given i.m. at 4.2 mg/kg not be repeated within a 21 day period.
Dissertation (MMedVet (Med))--University of Pretoria, 2003.
Companion Animal Clinical Studies
unrestricted

African trypanosomiasis remains a major health problem to both humans and animals due to lack of effective treatment or vaccine to control the disease. Animal trypanosomiasis is considered one of the most important diseases affecting livestock production and agricultural development in sub-Saharan Africa. Although the use of trypanocides remain the most important method for controlling the disease in animals, the mechanisms of action of these compounds are not completely known. The overall aim of this thesis is to decipher the molecular mechanisms involved in Trypanosoma congolense-induced cytokine production and how this is modulated by the trypanocide, Diminazene aceturate (Berenil). First, I investigated the molecular and biochemical mechanisms of action of Berenil to determine whether in addition to trypanolytic effect, it exerts a modulatory effect on the host immune system. Although it is known that T. congolense infection in mice is associated with increased production of pro-inflammatory cytokines by macrophages, the intracellular signaling pathways leading to the production of these cytokines remain unknown. Therefore, I investigated the innate receptors and intracellular signaling pathways that are involved in T. congolense-induced pro-inflammatory cytokine production in macrophages. Next I further determined whether the inhibitory effect of Berenil on proinflammatory cytokine production in macrophages is specific to T. congolense. I found that Berenil treatment significantly reduced the immune activation and proinflammatory cytokine production in infected mice suggesting that in addition to its direct trypanolytic effect, Berenil also modulates the host immune response to the parasite. Next, I show that T. congolense induced pro-inflammatory cytokine production in macrophages is dependent on phosphorylation of mitogen-activated protein kinase (MAPK) and signal transducer and activation of transcription (STAT) proteins in a TLR2-dependent manner. I further show that Berenil treatment downregulates T. congolense as well as LPS induced cytokine production by affecting the phosphorylation of MAPK and STAT proteins. Collectively, the results from this thesis provide novel insights into T. congolense-induced activation of the innate immune system and modulation of host immune response by Berenil. These findings are significant and could help in developing newer and better therapeutic strategies against the disease, in particular, and inflammatory responses in general.
October 2016

Bovine trypanosomosis is a serious constraint to livestock development in large parts of Mozambique. In most areas where tsetse flies are present, the disease in livestock is controlled using curative and prophylactic trypanocidal drugs. Those drugs have been used for many years and new drugs are unlikely to become available in the near future. As a result, trypanosomes have developed resistance against the currently available trypanocidal compounds. Drug resistance has been detected in various African countries and is a serious impediment to the control of livestock trypanosomosis. A study was initiated to determine whether drug resistant trypanosome strains are present in Zambézia Province of Mozambique. The aim of this study was to determine the sensitivity of Trypanosoma congolense isolates from Chinde, Nicoadala and Maganja da Costa Districts to diminazene aceturate, isometamidium chloride and homidium chloride. To assess the effect of the farming system and the intensity of drug regimens on the development of drug resistance, trypanosome isolates were collected from cattle from subsistence, semisubsistence and commercial livestock production systems. Drug-use practices in each of the production systems were determined using a questionnaire. The methodology used to assess the level of drugs resistance in the trypanosome isolates was the standardized method described by Eisler et al. (2001). Seven isolates were selected for resistance testing. For each of the seven isolates, five different doses varying between 0.01-20 mg/kg body weight for isometamidium chloride, 0.01-10 mg/kg body weight for homidium chloride and 1-30 mg/kg body weight for diminazene aceturate were used. For each dose rate six mice were treated intraperitoneally with the appropriate quantity of the drug dissolved in 0.2 ml of sterile distilled water 24 hours after the inoculation of the blood containing the trypanosomes. The control mice (six mice per trypanocidal drug) received the same amount of water without the drug. In four of the seven isolates high levels of multiple drug resistance (diminazene aceturate and isometamidium chloride) were detected. One isolate had a low level of multiple (diminazene aceturate and isometamidium chloride) drug resistance. Two isolates were susceptible to both diminazene aceturate and isometamidium chloride. One of those was highly susceptible to isometamidium chloride even at the lowest dose rate. The observed levels of drug resistance could in most cases be correlated to the drug-use practices in the particular livestock production system. The results obtained from homidium chloride treatment are not conclusive, because most the mice cured after receiving 10 mg/kg body weight of the drug. Hence more research is required to establish the homidium threshold in mice. The results of this study should be useful to define the strategy of disease control in places where resistance of trypanocide were been reported.
Dissertation (MSc (Veterinary Science))--University of Pretoria, 2005.
Veterinary Tropical Diseases
unrestricted

Cette thèse porte sur le développement d’une formulation colloïdale de diminazène (DMZ) à l’aide de nanoparticules polysaccharidiques cationiques (NP+) pour le traitement de la Trypanosomiase Africaine (TA).Nous avons étudié dans un premier temps le procédé de chargement des NP+ en DMZ base. Nous avons constaté que l’ajout de phospholipides dans la matrice des NP+ est nécessaire à l’association de DMZ. La quantité de phospholipide est d’ailleurs le facteur limitant de l’indice de saturation des NP+ en DMZ. Afin de ne pas dégrader le principe actif, lors de son chargement, le procédé choisi est le « post-loading » qui correspond à un mode opératoire en conditions douces : ajout d’une solution de DMZ dans une suspension de NP+ à cœur huileux. Nos résultats montrent que cette formulation reste stable durant 6 mois à 4°C ne libérant pas de DMZ et le protégeant de l’oxydation. Dans un second temps, nous avons évalué l’efficacité thérapeutique du DMZ formulé. Les tests in vitro sur Trypanosoma brucei brucei montrent une amélioration de l’activité trypanocide du DMZ. Les tests réalisés sur un modèle aigu de TA, ont mis en évidence que la dose efficace est équivalente au DMZ libre (3 mg/kg)
This thesis focuses on the development of a colloidal formulation of diminazene (DMZ) using cationic polysaccharide nanoparticles (NP+) for the treatment of African Trypanosomiasis. We first studied the process of DMZ loading in NP+. The addition of phospholipids in the matrix of the NP+ appeared to be necessary for the DMZ association. So, the amount of phospholipids is the limiting factor of the saturation index of NP+ with DMZ. To avoid the drug degradation during its formulation, we choose the \\\"post-loading\\\" technique which corresponds to a procedure with mild conditions: adding a DMZ solution in a suspension of NP+ containing an oily core. DMZ loaded into 70DGNP+ was found to be protected against oxidation and was stable for at least 6 months at 4°C. In a second step, we evaluated the therapeutic efficacy of formulated DMZ. In vitro tests on Trypanosoma brucei brucei showed an improvement of the DMZ trypanocidal activity. Tests on an acute model of Trypanosomiasis showed that the effective dose is equivalent to the free DMZ (3 mg / kg)

Bovine babesiosis is considered one of the most economically important tick-borne diseases in tropical and subtropical areas. Thus, it is important to understand the disease in terms causative agent, vectors, hosts, and distribution. Babesia is the causative agent of the disease and has a life cycle both in the invertebrate and vertebrate hosts. The major bovine species are B. bovis, B. bigemina, found in the tropics and sub tropics while B. divergens and B. major are found in the temperate regions. Bovine babesiosis is transmitted by the one-host cattle ticks, formerly in the genus Boophilus and now Rhipicephalus. In endemic areas are tick management, immunization, and anti-babesia drugs or by a combination. Chemotherapy is important for controlling the disease either to treat field cases or to control artificially induced infections. Conventional drugs for treating bovine babesiosis are Imidocarb dipropionate and Diminazene aceturate. Ticks are controlled by application of acaricides, but tick resistance and environmental pollution are drawbacks.

Introdução: A hemoparasitose é uma patologia de alta casuística na rotina clínica veterinária, desencadeada por bactérias, protozoários, helmintos, possuindo como principal transmissor o carrapato em períodos do ano de maior incidência de calor e umidade, tendo em vista o potencial zoonótico. A babesiose é causada pelos protozoários Babesia Canis e Babesia gibsoni transmitida pelo carrapato Rhipicephalus sanguineus, esses parasitas causam a hemólise das hemácias. Já a anaplasmose é oriunda de bactérias intracelulares Anaplasma platys ou Anaplasma phagocytophilum transmitidas pelo carrapato Rhipicephalus sanguineus, causando trombocitopenia. A rangeliose é ocasionada por um piroplasma Rangelia vitalli, transmitida por carrapatos Rhipicephalus sanguineus e Amblyomma aerolatum, se replicando nos eritrócitos. Objetivo: Relatar um caso clínico de uma canina. Relato de caso: canina castrada, sem raça definida, com 1 ano e dois meses, pesando 11,4 Kg, sendo atendida em uma clínica veterinária particular em Caxias do Sul/RS, apresentando apatia, hematoquezia, anorexia, prostração, epistaxe, sangramento em pontas de orelhas, mucosas hipocoradas com petéquias e febre. Durante o atendimento foi realizada coleta sanguínea para avaliação hematológica, esfregaço sanguíneo periférico da orelha, bioquímica sérica (creatinina, fosfatase alcalina, ureia, transaminase pirúvica) e urinálise, apresentando alterações, tais como anemia regenerativa, leucocitose por neutrofilia com desvio a esquerda, linfocitose, trombocitopenia, na urinálise houve presença de hemoglobina, leucócitos, proteinúria. No exame de esfregaço de sangue periférico apresentou-se negativo para hemoparasitas. O diagnóstico definitivo foi através da Reação em Cadeia da Polimerase (PCR), na qual evidenciou os agentes patogênicos de babesiose, rangeliose e anaplasmose. O tratamento instituído foi doxiciclina (5 mg/kg/q.12h durante 28 dias), azitromicina (10 mg/Kg/q.24h durante 10 dias), diaceturato de diminazeno (0,5ml/2Kg) repetindo em 14 dias a dose com prévia aplicação de atropina (0,044 mg/Kg), suplemento vitamínico mineral aminoácido (1 ml/q.24h). O animal se manteve bem clinicamente durante o tratamento, obtendo cura da enfermidade. Conclusão: Mesmo com o diagnóstico negativo de esfregaço sanguíneo periférico, com a suspeita clínica do animal foi solicitado PCR para confirmar a patologia, assim foi de suma importância a pesquisa de hemoparasitas pelos sinais clínicos do canino, juntamente do tratamento precoce e assertivo.