Marina Clare Vinaud

Experimental encephalitis caused by Taenia crassiceps cysticerci in mice

OBJECTIVES To present the experimental model of neurocysticercosis (NCC) caused by Taenia crassiceps cysticerci, to describe the inflammatory process, susceptibility, or resistance of BALB/c and C57BL/6 mice to this infection, and to describe the host-parasite relationship. METHODS The animals were intracranially inoculated with initial stage T. crassiceps cysticerci. They were euthanized at 7, 30, 60, and 90 days after the inoculation. Their encephala were removed for the histopathologic analysis, classification of the parasites, and inflammatory lesions. RESULTS Experimental NCC was observed on both mice lineages. BALB/c mice presented inflammatory lesions with greater intensity, inducing necrosis on late stage parasites, and with an acute inflammation pattern, while C57BL/6 mice showed greater capability on provoking early necrosis in the cysticerci, which showed a chronic inflammation pattern. CONCLUSIONS This experimental model induced NCC on mice with characteristic inflammation and lesions. C57BL/6 mice were able to induce precocious necrosis of the parasites presenting inflammatory lesions with lower intensity.

Epidemiological factors associated with seropositivity for toxoplasmosis in pregnant women from Gurupi, State of Tocantins, Brazil

INTRODUCTION Knowledge of the prevalence and risk factors for Toxoplasma gondii dissemination among pregnant women is relevant because the parasite can be spread from mother to infant. The objective of this study was to assess the epidemiology and risk factors of toxoplasmosis in pregnant women from Gurupi, State of Tocantins, Brazil, from February 2012 to June 2013. METHODS The study population included 487 pregnant women. Sociodemographic, dietary and cultural data were collected using a standardized and validated form. Peripheral blood was collected for serologic testing using the ELISA test (IgM/IgG antibodies). The data were analyzed by comparing seropositivity with risk factors using crude and adjusted odds ratios. RESULTS The prevalence rate for IgG and IgM antibodies was 68.7% and 5.7%, respectively. Sociodemographic characteristics associated with toxoplasmosis risk included the following: education level ≤ 8 years (OR: 6.612; CI: 1.450-30.144), age ≥ 30 years (OR: 5.273; CI: 1.166-23.844), working outside the home (OR: 1.604; CI: 1.015-2.536), and family income of two minimum wages or lower (OR: 2.700; CI: 1.891-8.182). Regarding dietary habits, there was a significant association of seropositivity with meat intake (OR: 1.78; CI: 1.149-4.080), cutting vegetables without washing the cutting board beforehand (OR: 2.051; CI: 1.165-3.614), frequent intake of vegetables (OR: 2.051; CI: 1.368-3.006) and in natura milk intake (OR: 2.422; CI: 1.014-5.785). CONCLUSIONS The high prevalence rates of toxoplasmosis in Gurupi are related to age, raw meat and in natura milk intake, as well as education level, working outside the home, and poor hygienic habits during meal preparation.

Taenia crassiceps: host treatment alters glycolisis and tricarboxilic acid cycle in cysticerci.

Human cysticercosis by Taenia crassiceps is rare although it is considered of zoonotic risk, especially to immunocompromised individuals. Albendazole and praziquantel are widely used and effective in its treatment. Their active forms inhibit the glucose uptake by the parasite and induce muscle contractions that alter its glycogen levels interfering in the energetic metabolism of the parasite and leading to its death. The aim of this study was to evaluate alterations in glycolysis, the tricarboxylic acid cycle and glucose concentrations caused by low dosage treatments of the hosts with albendazole and praziquantel. Therefore, T. crassiceps intraperitoneally infected mice were treated by gavage feeding with 5.75 or 11.5 mg/kg of albendazole and 3.83 or 7.67 mg/kg of praziquantel. The treated mice were euthanized after 24 h and the cysticerci collected were morphologically classified into initial, larval or final phases. Concentrations of the organic acid produced and glucose were evaluated to detect alterations into the glycolysis and the tricarboxylic acid cycle pathways through chromatography and spectrophotometry. The low dosage treatment caused a partial blockage of the glucose uptake by the cysticerci in spite of the non significant difference between its concentrations. An activation of the tricarboxylic acid cycle was noted in the cysticerci that received the treatment due to an increase in the production of citrate, malate and α-ketoglutarate and the consumption of oxaloacetate, succinate and fumarate. The detection of α-ketoglutarate indicates that the cysticerci which were exposed to the drugs after host treatment present different metabolic pathways than the ones previously described after in vitro treatment.

Fatty acids oxidation and alternative energy sources detected in Taenia crassiceps cysticerci after host treatment with antihelminthic drugs

Human cysticercosis caused by Taenia crassiceps is rare however it is considered of zoonotic risk. The treatment of the infected patients was successful when using albendazole or praziquantel. The active forms of albendazole inhibit the glucose uptake and the active forms of praziquantel alter glycogen levels and nutrients absorption. The aim of this study was to analyze the production of organic acids that indicate the oxidation of fatty acids and the use of alternative energy sources from T. crassiceps cysticerci removed from the peritoneal cavity of mice treated with low dosages of albendazole (5.75 and 11.5mg/kg) or praziquantel (3.83 and 7.67 mg/kg). The beta-hydroxibutyrate production was higher by the larval stage cysticerci in all treated groups and the propionate production was higher in final stage cysticerci treated with 11.5mg/kg of albendazole when compared to the control group. The larval stages of cysticerci from the groups treated with 5.75 mg/kg of albendazole and 3.83 mg/kg of praziquantel produced more urea than the initial and final stages which indicate amino acids breakdown. We conclude that it was possible to detect the fatty acid oxidation and amino acids breakdown which indicate the use of alternative energy production sources as the used dosages only cause a partial blockage of the glucose uptake and leads to metabolic alterations in the cysticerci. The metabolic behavior observed after host treatment was different from former descriptions of the in vitro one which indicates great host-parasite interaction.

Elucidating the influence of praziquantel nanosuspensions on the in vivo metabolism of Taenia crassiceps cysticerci

The aim of this work was to develop nanosuspensions of praziquantel (PZQ) and to evaluate their influence on the energetic metabolism of cysticerci inoculated in BALB/c mice. We analyzed metabolic alterations of glycolytic pathways and the tricarboxylic acid cycle in the parasite. The nanosuspensions were prepared by precipitation and polyvinyl alcohol (PVA), poloxamer 188 (P188) and poloxamer 407 (P407) were used as stabilizers. Nanosuspension prepared with PVA had a particle size of 100nm, while P188- and P407-based nanosuspensions had particle sizes of 74nm and 285nm, respectively. The zeta potential was -8.1, -8.6, and -13.2 for the formulations stabilized with PVA, P188 and P407, respectively. Treatments of T. crassiceps cysticerci-infected mice resulted in an increase in glycolysis organic acids, and enhanced the partial reversion of the tricarboxylic acid cycle, the urea cycle and the production of ketonic bodies in the parasites when compared to the groups treated with conventional PZQ. These data suggest that PZQ nanosuspensions greatly modified the energetic metabolism of cysticerci in vivo. Moreover, the remarkable metabolic alterations produced by the stabilizers indicate that further studies on nanoformulations are required to find potentially suitable nanomedicines.

Aspectos macroscópicos da cardiopatia chagásica crônica no envelhecimento

OBJECTIVE To describe the macroscopic characteristics of chronic Chagas heart disease in autopsied elderly. METHODS The elderly studied were 60 or older. Twenty of them had chronic Chagas heart disease (CHD) and positive serology for the disease, and 14 had no heart disease (WHD) nor morphological changes suggestive of it and were serologically negative for Chagas disease. RESULTS The CHD elderly had cardiac weight greater than the WHD (385 +/- 141.1 vs 306.8 +/- 62.1g, respectively; p > 0.05), in addition to significantly higher heart weight-to-body weight ratio (0.71% [0.5-1.42%] vs 0.59% [0.47-0.91%] p < 0.05). When compared, the CHD elderly presented lower fibrous thickening and/or atherosclerosis in the ascending aorta, mitral and tricuspid valves, and left and right coronaries than the WHD elderly. In the aortic and mitral valves, the lesions were significantly less severe (p < 0.05). Left ventricular apical lesion was observed in 45% of the CHD elderly, and intracardiac thrombosis in the left ventricle was found in 10% of them. CONCLUSION Fibrous thickening and/or atherosclerosis were found to be less severe in the valves and arteries of the CHD elderly. Moreover, heart weight and intracardiac thrombosis frequency were lower than those detailed in the literature for non-elderly individuals.

Anaerobic Metabolism in T4 Acanthamoeba Genotype

Members of the genus Acanthamoeba are of the most common protozoa that has been isolated from a variety of environment and affect immunocompromised individuals, causing granulomatous amoebic encephalitis and skin lesions. Acanthamoeba, in immunocompetent patients, may cause a keratitis related to corneal microtrauma. These free-living amoebas easily adapt to the host environment and wield metabolic pathways such as the energetic and respiratory ones in order to maintain viability for long periods. The energetic metabolism of cysts and trophozoites remains mostly unknown. There are a few reports on the energetic metabolism of these organisms as they are mitochondriate eukaryotes and some studies under aerobic conditions showing that Acanthamoeba hydrolyzes glucose into pyruvate via glycolysis. The aim of this study was to detect the energetic metabolic pathways with emphasis on anaerobic metabolism in trophozoites of three isolates of Acanthamoeba sp belonging to the T4 genotype. Two samples were collected in the environment and one was a clinical sample. The evaluation of these microorganisms proceeded as follows: rupture of trophozoites (7.5 × 103 parasites/ml) and biochemical analysis with high performance liquid chromatography and spectrophotometry. The anaerobic glycolysis was identified through the detection of glucose, pyruvate, and lactate. The protein catabolism was identified through the detection of fumarate, urea, and creatinine. The fatty acid oxidation was identified through the detection of acetate, beta-hydroxybutyrate, and propionate. The detected substances are the result of the consumption of energy reserves such as glycogen and lipids. The anaerobic glycolysis and protein catabolism pathways were observed in all three isolates: one clinical and two environmental. This study represents the first report of energetic pathways used by trophozoites from different isolates of the T4 genotype Acanthamoeba.

Alternative energy production pathways in Taenia crassiceps cysticerci in vitro exposed to a benzimidazole derivative (RCB20)

Biochemical studies of benzimidazole derivatives are important to determine their mode of action and activity against parasites. The lack of antihelminthic alternatives to treat parasitic infections and albendazole resistance cases make the search for new antiparasitary drugs of utmost importance. The 6-chloro-5-(1-naphthyloxy)-2-(trifluoromethyl)-1H-benzimidazole (RCB20) is a benzimidazole derivative with promising effect. This study evaluated the effect of different concentrations of RCB20 in the alternative energetic pathway of in vitro Taenia crassiceps cysticerci. The parasites were in vitro exposed to 6.5 and 13 µM of RCB20 and albendazole sulfoxide (ABZSO). The quantification of acetate, acetoacetate, β-hydroxybutyrate, fumarate and propionate was performed by high-performance liquid chromatography. The quantification of urea, creatinine and total proteins was performed by spectrophotometry. The increase in β-hydroxybutyrate reflects the enhancement of the fatty acid oxidation in the treated groups. Volatile fatty acids secretion, acetate and propionate, was increased in the treated groups. The secretion mechanisms of the treated parasites were impaired due to organic acids increased concentrations in the cysticerci. It is possible to conclude that the metabolic effect on alternative energetic pathways is slightly increased in the parasites treated with RCB20 than the ones treated with ABZSO.

Changes in energetic metabolism of Biomphalaria glabrata (Mollusca, Planorbidae) in response to exogenous calcium.

Calcium is considered an essential element for the metabolism of aquatic snail Biomphalaria glabrata (Say, 1818), intermediate host of Schistosoma mansoni Sambon, 1907 in Brazil, and represents a limiting factor to its distribution and adaptation to the environment. This study investigated the effect of different concentrations of exogenous CaCO3 on the energetic metabolism of B. glabrata for better understanding the physiological interference of chemical elements dissolved in the environment with the physiology of this species. Sixty-day-old snails were distributed into six groups, five exposed to different concentrations of CaCO3 (20, 40, 60, 80 and 100 mg/L) and a control group. The exposure to CaCO3 was assessed over time, with analysis of 15 snails of each group in the following intervals: 1, 14, 21 or 30 days for hemolymph extraction. Concentrations of calcium and glucose in the hemolymph were determined by commercial kits, and organic acids were extracted using an ion exchange column and analyzed by high-performance liquid chromatography. Concentration of calcium in the hemolymph showed no significant difference (p>0.05) from the control group and between the concentrations tested. Concentration of glucose decreased (p<0.05) in the treatments of exposure to 20 and 40 mg/L and increased when exposed to 80 and 100 mg/L CaCO3 compared to control and to other concentrations tested over 30 days. The organic acids pyruvate, oxaloacetate, citrate, succinate, fumarate, beta-hydroxybutyrate and lactate presented increased concentrations, while propionate and acetoacetate, decreased concentrations, when exposed to CaCO3 compared to control. Considering the influence of different periods of exposure to CaCO3, on the 14th day, there were stronger alterations in the metabolism of B. glabrata. In conclusion, exposure to CaCO3 reduced the concentration of glucose, which is metabolized into pyruvate, the final product of glycolysis, and also influenced the energetic metabolism pathways, indicating an aerobic or partially anaerobic functioning.

Low intensity ultrasound therapy induces angiogenesis and persistent inflammation in the chronic phase of the healing process of third degree burn wounds experimentally induced in diabetic and non-diabetic rats

PURPOSE To evaluate the effects of low intensity ultrasound on the healing process of third degree burn wounds in experimentally induced diabetic Wistar rats. METHODS One hundred rats were divided into: control group; non-diabetic treated group; diabetic control group; diabetic treated group. The therapy was performed with a 3MHz ultrasound application, pulsed emission at 100Hz frequency, modulated at 20% with a dosage of 0.5W/cm2 during three minutes throughout 30 days. The surgical debridement of the wound was performed once at day 2. The wounds were morphometrically, macroscopically and microscopically evaluated at 3, 7, 14, 21 and 30 days. RESULTS The wound contraction and collagen quantification were higher in all treated groups. Macroscopically, necrosis was higher in the diabetic control group. Granulation tissue was higher in treated groups during the proliferative and remodeling phase. Microscopically, there were greater mononuclear inflammatory infiltration, angiogenesis and fibroblast quantification in treated groups during the proliferative and remodeling phases. CONCLUSIONS therapeutic ultrasound is beneficial in the inflammatory and proliferative phases of the healing process because it controlled the necrotic tissue, increased the granulation tissue and wound contraction. However in the remodeling phase it is not beneficial because of the continued angiogenesis and a mononuclear inflammatory infiltration.