Luiz Erlon A. Rodrigues

Renal Involvement in Visceral Leishmaniasis

In a prospective study of 50 patients with visceral leishmaniasis, laboratory abnormalities suggestive of renal involvement were not infrequent. Proteinuria and/or microscopic hematuria or pyuria were observed in 51% of such cases. Twenty-four hour urinary protein excretion was elevated in 57% of patients in all cases below 1g/24 hours. An abnormal acid-load test was demonstrated in 12 of 18 patients studied before therapy of the parasitic infection with N-methyl-glucamine. Of interest was the demonstration of tubulo-interstitial involvement in the renal histology of all seven patients studied; also, in five of seven patients there was a proliferative glomerulonephritis, usually mild, on histologic examination. In general, there was a tendency to subsidence of abnormal laboratory findings within one month after specific therapy. Renal involvement in visceral leishmaniasis was mild and seemed to revert with the cure of the leishmanial infection.

The lysosomal stability as a biomarker for the determination of pollution in aquatic environments

A procura de biomarcadores de agentes poluidores, mais simples e menos custosos, tem levado ao estudo dos lisossomos, isolados de animais componentes da biota nos ambientes contaminados, principalmente por poluentes com caracteristicas lipofilicas, a exemplo dos hidrocarbonetos policiclicos e seus derivados. Este trabalho estudou os efeitos provocados por 05 diferentes formulacoes de gasolina sobre a estabilidade de lisossomos, isolados de figado de tilapia (Oreochromis niloticus). A integridade funcional das membranas lisossomicas foi avaliada atraves da atividade da fosfatase acida, expressa em mU/mg de proteinas totais. Os resultados obtidos mostraram que existem alteracoes significativas na estabilidade dos lisossomos isolados de figado de tilapias submetidas aos efeitos de hidrocarbonetos presentes no meio ambiente. Portanto, levando em conta a simplicidade, a sensibilidade de resposta e o baixo custo, os autores recomendam a avaliacao da atividade lisossomica, como uma importante ferramenta para o estudo dos efeitos da poluicao dos meios aquaticos.

Bioquímica da esquistossomose mansônica: VII. Alterações lipídicas das membranas lisossômicas durante a faze inicial da agressão hepática

Aiming at investigating the changes on the lipidic constitution of hepatic lysosomal membranes at the initial phase of schistosomatic damage, mice have been infected with 30 cercarias and employed for essais in the 30th day of infection. The triacylglycerois decreased from 220 +/- 48 micrograms/mg of total proteins in the control mice, to 165 +/- 22 micrograms/mg in the infected ones. Similarly, the free cholesterol, also decreased from 539 +/- 80 to 396 +/- 54 micrograms/mg; the cholesterol esters from 270 +/- 35 to 216 +/- 36 micrograms/mg and the phosphatidylcholines from 44 +/- 5.7 to 31 +/- 4.9 micrograms/mg. The phosphatidylserines the phosphatidylethanolamines and the sphingomyelins increased, respectively from 58 +/- 9.7 to 60 +/- 8.5, from 72 +/- 7.8 to 111 +/- 15.7 and from 36 +/- 4.9 to 63 +/- 7.1 micrograms/mg. The free fatty acids showed no statistical significance on their variations. They varied from 1.7 +/- 0.25 microEq/g in the controls to 1.8 +/- 0.39 microEq/g in the infected animals. These results indicated that in the initial phase of hepatic schistosomiasis, before the formation of granulomas, important changes on the lipidic constitution of lysosomal membranes can be detected. It seems that they are provoked by the catabolic excreted by immature or adult worms of Schistosoma mansoni present in the portal vein system.Com o intuito de se estudarem as alteracoes nos teores lipidicos, constituintes das membranas lisossomicas, em figados, durante a fase inicial da agressao esquistossomotica, foram utilizados camundongos infectados com 30 cercarias e 30 dias de infeccao. Os triagliceridios passaram de 200 ± 48 µg/mg de proteinas totais nos controles, para 165 ± 22 µg/mg, nos infectados. Na mesma ordem tambem diminuiram o colesterol livre de 539 ± 80, para 396 ± 54 µg/mg; os esteres do colesterol de 270 ± 35, para 216 ± 36 µg/mg e os colinafosfatidios de 44 ± 5,7 para 31 ± 4,9 µg/mg. Os serinafosfatidios, os etanolaminafosfatidios e os esfingofosfatidios aumentaram, respectivamente de 58 ± 9,7 para 60 ± 8,5, de 72 ± 7,8 para 111 ± 15,7 e de 36 ± 4,9 para 63 7,1 µg/mg. Os acidos graxos livres nao se alteram significativamente, passaram de 1,7 ± 0,35 µEq/g, nos controles, para 1,8 ± 0,29 Eq/g nos animais infectados. Esses resultados padecem indicar que na fase inicial de esquistossomose mansonica hepatica, antes da formacao dos granulomas, sao detectadas alteracoes importantes na constituicao lipidica das membranas do compartimento lisossonico. Elas, talvez, sejam devidas a produtos catabolicos, excretados por vermes imaturos ou adultos, presentes em vasos do sistema portal.

Pentoxifylline in Ischemia-Induced Acute Kidney Injury in Rats

Ischemia is an important cause of acute kidney injury (AKI). Pentoxifylline has been shown to improve tissue oxygenation and endothelial function and inhibit proinflammatory cytokine production. The aim of this study was to evaluate a possible renal protective effect of pentoxifylline against ischemia by measuring mitochondrial respiratory metabolism as an index of cell damage. Rats were submitted to right nephrectomy. The left kidney was submitted to ischemia by clamping the renal artery for 45 minutes. Immediately after release of the clamp, 1 mL of a solution containing 20 mg of pentoxifylline/mL was injected intravenously, while a control group received 1 mL of normal saline intravenously. Five minutes after the injection, the left kidney was removed, homogenized, and subjected to refrigerated differential centrifugation. Mitochondrial respiratory metabolism was measured polarographically. The mitochondria isolated from the kidneys of saline-treated rats had an endogenous respiration of 9.20 ± 1.0 ηmol O2/mg protein/min compared to 8.9 ± 1.4 ηmol O2/mg protein/min in the pentoxifylline-treated rats (p > 0.05). When stimulated by sodium succinate, the respiratory metabolism increased in a similar fashion in both groups of animals: 17.9 ± 2.3 and 18.1 ± 2.1ηmol O2/mg protein/min in the untreated and pentoxifylline-treated groups, respectively (p > 0.05). In the present study, pentoxifylline was not found to exert any protective effect on the kidney. It is possible that at the time of pentoxifylline administration, the mitochondria had already been damaged by the process of ischemia, and its effect may have been insufficient to reverse cell damage.

Neospora caninum: infection induces high lysosomal activity.

Neospora caninum is a protozoan that causes abortion in cattle and neuromuscular lesions in dogs, making it an important target of veterinary medicine. Lysosomes are cellular organelles responsible for important biological functions as cellular defense mechanisms. The aim of this work was to evaluate the lysosomal stability of rat gliocytes infected in vitro with N. caninum. Rat glial cultures were infected at a ratio of 1:1 (cell/parasite). The enzymatic activity of acid phosphatase (orthophosphoric-monoester phosphohydrolase, EC 3.1.3.2) was assayed in the medium of control and infected cell cultures. The activity observed at 24h of incubation was 0.4±0.08mU/mg/min for control cells and 1.3±0.5mU/mg/min for infected cells. After 72h, control and infected cells exhibited activities of 1.3±0.5 and 4.1±0.9mU/mg/min, respectively. These results suggested that lysosomal compartment plays an important role in the mechanisms of cellular infection by N. caninum.

Effect of Acute Experimental Uremia on the Stability of Liver Lysosomal Membranes

Acute uremia was induced in male Swiss albino mice by complete urethral ligation and the animals were sacrificed 2, 4-6, 24, and 48 h after operation. Sham-opeated animals (without the urethral ligation) were similarly treated. The blood urea levels of animals with total urinary tract obstruction went up to 175 mg/100 ml at 4-6 h of urethral ligation and reached an average level of 827 mg/100 ml at 48 h, while the control group exhibited and average blood urea level of 37 mg/100 ml. Lysosomes obtained from livers of uremic mice sacrificed at different time intervals demonstrated a lability of the lysosomal membranes (as determined by the acid phosphatase activity in mU/mg) which was maximal at 4-6 h of urethral ligation, declining towards normal at 24 and 48 h, despite an increase in the animals blood urea. In vitro studies exposing liver lysosomes to progressively higher urea concentrations (differences of as much as 100,000 times) did not reveal any effect of urea upon the stability of lysosomal membranes. The reason for the lability of lysosomal membranes in the uremic group was not apparent in the present study.

The effect of acute uremia on liver mitochondrial activity.

The effect of acute uremia on the liver mitochondrial activity was studied in Swiss albino mice subjected to complete urethral obstruction and sacrificed at different time intervals. The specific respiratory coefficient (measured as microliters of oxygen utilized per milligram of total proteins X 10(-1)) was similar in uremic and sham-operated control groups. The utilization of succinate as substrate was also similar in uremic and controls. There was a tendency for decreasing utilization of alpha-glutarate as substrate by the uremic group, particularly after 48 h of total urinary obstruction. There was no correlation between the retention of urea and the degree of mitochondrial respiratory inhibition.

Bioquímica da esquistossomose mansônica: envolvimento dos siderossomos nos processos inflamatórios hepáticos

The inflammatory processes that develop during the advanced stages of hepatic Schistosomiasis mansoni have been related in this study to: (a) accumulation of siderosomes; (b) capacity of the ferrous/ferric ions to unleash the formation of free radicals; (c) peroxidation of membranaceous lipids and; (d) reduction of stability of the membranes of several components of the hepatic lysosomal compartment. The lysosomes isolated from the livers of infected mice by 100 cercariae, with 80 and 100 days of infection, were respectively 2.5 and almost 4 times weaker than the control ones isolated from livers of non-infected mice. The presence of a great quantity of siderosomes has been demonstrated by transmission electronic microscopy and X-ray spectrometry microanalysis.

Bioquímica da esquistossomose mansônica. VI - alterações do compartimento lisossômlco hepático relacionadas ao tempo de infecção

Schistosoma mansoni and/or its eggs cause important hepatic pathology distinguished by very characteristic anatomo-clinicalfeatures. If carried by the blood stream, the worms are able to occlude dichotomic branches of larger diameter of the portal system. These worms, when dead, produce lesions that are sometimes extensive, initially necrotic, then inflammatory and finally cicatricial. These lesions are always circumscribed and not systematized. Besides penetrating into the tiny non-dichotomic branches of the periductal net, the eggs reach the branches of distribution or even the afferent venulae, occluding some of them. Consequently intravascular granulomas are formed which can lead to an interruption of the portal blood stream at this level and to changes in the intralobular circulation. The decrease of the rate of available oxygen and consequent decrease in the intra and extracellular pH are potent labilisers of membranes of several components of the lysosomal compartment. The exit of acid hydrolases, cationic proteins and neutral hydrolases from these organelles brings about major tissular aggression, represented by the formation and maintenance of the typical inflammatory processes of this parasitism. In this work lysosomal activity related to hepatic schisto-somiasis mansoni has been studied. The results indicated that the functional integrity of the lysosomal membrane complexe had been significantly changed. These changes have been observed from the second month of infection and there seems to be a close relationship between the severity of the liver inflammatory lesions and a greater lysosomal lability.

Bioquímica da esquistossomose mansônica: V - atividade mitocondrial em fígados e rins de sagüis (Callitrix penicillata) infestados pelo Schistosoma mansoni

Foram estudadas mitocondrias isoladas de figados e rins de saguis (Callitrix penicillata) infestados pela inoculacao de 200 cercarias e entre 80 e 100 dias de infeccao, nos aspectos relativos as suas atividades respiratorias endogenas, bem como frente ao succinato e ao alfa ceto glutarato de sodio. Cada experiencia foi acompanhada de controle, usando-se mitocondrias isoladas de figados e rins de animais nao infectados. As medidas das atividades respiratorias foram efetuadas polarograficamente e expressas em microlitros de oxigenio consumidos por miligrama de proteinas totais por minuto. Os resultados mostraram que as respiracoes endogenas das mitocondrias isoladas dos animais infectados foram sempre maiores do que aquelas observadas nos controles. Detectou-se um estimulo para o figado de 217% e para o rim de 84%. O succinato de sodio estimulou em 85% a respiracao das mitocondrias dos figados dos animais controles, enquanto a inibiu de 39% nos infectados. Com referencia aos rins, este mesmo substrato estimulou a referida respiracao tanto nos controles quanto nos infectados, em 89% e 94% respectivamente. O alfa ceto glutarato estimulou as mitocondrias hepaticas isoladas dos controles em 48% e as renais em 84%. Nos animais esquistossomoticos ou ele nao modificou a capacidade respiratoria mitocondrial como se observou para o rim, ou a inibiu de 58%, no caso do figado. Os dados obtidos sugerem que o figado sofre muito mais, em termos bioquimicos, com a esquistossomose mansonica do que os rins, pelo menos em nossas condicoes experimentais. As atividades do sistema enzimatico succinato desidrogenase e do complexo alfa ceto glutarato desidrogenase permitiram identificar bioquimicamente, em nossos animais esquistossomoticos, varios graus de lesao celular, principalmente hepaticos, que vao desde os mais simples, decorrentes de modificacoes da fisico-quimica dos sistemas de membranas, ate os mais graves, tipo necrose.Foram estudadas mitocondrias isoladas de figados e rins de saguis (Callitrix penicillata) infestados pela inoculacao de 200 cercarias e entre 80 e 100 dias de infeccao, nos aspectos relativos as suas atividades respiratorias endogenas, bem como frente ao succinato e ao alfa ceto glutarato de sodio. Cada experiencia foi acompanhada de controle, usando-se mitocondrias isoladas de figados e rins de animais nao infectados. As medidas das atividades respiratorias foram efetuadas polarograficamente e expressas em microlitros de oxigenio consumidos por miligrama de proteinas totais por minuto. Os resultados mostraram que as respiracoes endogenas das mitocondrias isoladas dos animais infectados foram sempre maiores do que aquelas observadas nos controles. Detectou-se um estimulo para o figado de 217% e para o rim de 84%. O succinato de sodio estimulou em 85% a respiracao das mitocondrias dos figados dos animais controles, enquanto a inibiu de 39% nos infectados. Com referencia aos rins, este mesmo substrato estimulou a referida respiracao tanto nos controles quanto nos infectados, em 89% e 94% respectivamente. O alfa ceto glutarato estimulou as mitocondrias hepaticas isoladas dos controles em 48% e as renais em 84%. Nos animais esquistossomoticos ou ele nao modificou a capacidade respiratoria mitocondrial como se observou para o rim, ou a inibiu de 58%, no caso do figado. Os dados obtidos sugerem que o figado sofre muito mais, em termos bioquimicos, com a esquistossomose mansonica do que os rins, pelo menos em nossas condicoes experimentais. As atividades do sistema enzimatico succinato desidrogenase e do complexo alfa ceto glutarato desidrogenase permitiram identificar bioquimicamente, em nossos animais esquistossomoticos, varios graus de lesao celular, principalmente hepaticos, que vao desde os mais simples, decorrentes de modificacoes da fisico-quimica dos sistemas de membranas, ate os mais graves, tipo necrose.