The toxicity of Aspidosperma subincanum to MCF7 cells is related to modulation of oxidative status and proinflammatory pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Cancer is an inflammatory disease because carcinogenesis and tumor progression depend on intrinsic and extrinsic inflammatory pathways. Although species of the genus Aspidosperma are widely used to treat tumors, and there is ethnopharmacological evidence for traditional use of the species A. subincanum as an anti-inflammatory agent, its antineoplastic potential is unknown.

AIM OF THE STUDY

To evaluate toxic effects of the indole alkaloid-rich fraction (IAF) of A. subincanum on the MCF7 cell line and identify some of the anti-inflammatory mechanisms involved.

MATERIALS AND METHODS

Chromatographic analyses were performed by ultra-high-performance liquid chromatography with electrospray ionization mass spectrometry, and cytotoxic and antiproliferative effects of IAF were verified by MTT and clonogenic assays. Cell cycle alterations were analyzed by measuring DNA content, while propidium iodide and acridine orange staining was performed to determine the type of induced cell death. The expression of apoptosis markers and proteins involved in cell proliferation and survival pathways was analyzed by immunoblotting, RT-qPCR, and ELISAs. Interference with redox status was investigated using a DCFH-DA probe and by measuring catalase activity.

RESULTS

Chromatographic analyses showed that IAF is a complex mixture containing indole alkaloids. IAF selectively exerted toxic and antiproliferative effects, elevating the Bax/Bcl-xL ratio and inducing apoptosis in MCF7 cells. IAF decreased intracellular reactive oxygen species levels and increased catalase activity, while reducing the IL-8 level and suppressing COX-2 expression.

CONCLUSIONS

IAF induces apoptosis in MCF7 cells by suppressing COX-2 expression while reducing IL-8 levels and intracellular content of reactive oxygen species.

Docking and molecular dynamics predicted B-DNA and dihydropyrimidinone selenoesters interactions elucidating antiproliferative effects on breast adenocarcinoma cells

Dihydropyrimidinones have demonstrated different biological activities including anticancer properties. Cytotoxic potential and antiproliferative potential of new dihydropyrimidinone-derived selenoesters (Se-DHPM) compounds were assessed in vitro against the breast adenocarcinoma cells (MCF-7). Among the eight Se-DHPM compounds tested just 49A and 49F were the most cytotoxic for MCF-7 and the most selective for the non-tumor strain (McCoy) and reduced cell viability in a time- and concentration-dependent manner. Compounds 49A and 49F increased the rate of cell death due to apoptosis and necrosis comparatively to the control, however only the 49F showed antiproliferative potential, reducing the number of colonies formed. In the molecular assay 49A interacts with CT-DNA and caused hyperchromism while 49F caused a hypochromic effect. The intercalation test revealed that the two compounds caused destabilization in the CT-DNA molecule. This effect was evidenced by the loss of fluorescence when the compounds competed and caused the displacement of propidium iodide. Simulations (docking and molecular dynamics) using B-DNA brought a greater understanding of ligand-B-DNA interactions. Furthermore, they predicted that the compounds act as minor groove ligands that are stabilized through hydrogen bonds and hydrophobic interactions. However, the form of interaction foreseen for 49A was more energetically favorable and had more stable hydrogen bonds during the simulation time. Despite some violations foreseen in the ADMET for 49F, the set of other results point to this Se-DHPM as a promising leader compound with anti-tumor potential for breast cancer.Communicated by Ramaswamy H. Sarma.

Novel Dihydropyrimidinone-Derived Selenoesters as Potential Cytotoxic Agents to Human Hepatocellular Carcinoma: Molecular Docking and DNA Fragmentation

BACKGROUND AND OBJECTIVE

Evidence point out promising anticancer activities of Dihydropyrimidinones (DHPM) and organoselenium compounds. This study aimed to evaluate the cytotoxic and antiproliferative potential of DHPM-derived selenoesters (Se-DHPM), as well as their molecular mechanisms of action.

METHODS

Se-DHPM cytotoxicity was evaluated against cancer lines (HeLa, HepG2, and MCF-7) and normal cells (McCoy). HepG2 clonogenic assay allowed verifying antiproliferative effects. The propidium iodide/ orange acridine fluorescence readings showed the type of cell death induced after treatments (72h). Molecular simulations with B-DNA and 49H showed docked positions (AutoDock Vina) and trajectories/energies (GROMACS). In vitro molecular interactions used CT-DNA and 49H applying UV-Vis absorbance and fluorescence. Comet assay evaluated DNA fragmentation of HepG2 cells. Flow cytometry analysis verified HepG2 cell cycle effects. Levels of proteins (β-actin, p53, BAX, HIF-1α, γH2AX, PARP-1, cyclin A, CDK-2, and pRB) were quantified by immunoblotting.

RESULTS

Among Se-DHPM, 49H was selectively cytotoxic to HepG2 cells, reduced cell proliferation, and increased BAX (80%), and p53 (66%) causing apoptosis. Molecular assays revealed 49H inserted in the CT-DNA molecule causing the hypochromic effect. Docking simulations showed H-bonds and hydrophobic interactions, which kept the ligand partially inserted into the DNA minor groove. 49H increased the DNA damage (1.5 fold) and γH2AX level (153%). Besides, treatments reduced PARP-1 (60%) and reduced pRB phosphorylation (21%) as well as decreased cyclin A (46%) arresting cell cycle at the G1 phase.

CONCLUSION

Together all data obtained confirmed the hypothesis of disruptive interactions between Se-DHPM and DNA, thereby highlighting its potential as a new anticancer drug.

The Widely Used Antihelmintic Drug Albendazole is a Potent Inducer of Loss of Heterozygosity

The antihelmintic drug ABZ and its metabolites belong to the chemical family of benzimidazoles (BZM) that act as potent tubulin polymerization inhibitors, suggesting a potential re-direction of BZMs for cancer therapy. Applying UV-Vis spectrometry we here demonstrate ABZ as a DNA intercalator. This insight led us to determine the primary mode of ABZ action in mammalian cells. As revealed by RNA sequencing, ABZ did neither grossly affect replication as analyzed by survival and replication stress signaling, nor the transcriptome. Actually, unbiased transcriptome analysis revealed a marked cell cycle signature in ABZ exposed cells. Indeed, short-term exposure to ABZ arrested mammalian cells in G2/M cell cycle stages associated with frequent gains and losses of chromatin. Cellular analyses revealed ABZ as a potent mammalian spindle poison for normal and malignant cells, explaining the serious chromosome segregation defects. Since chromosomal aberrations promote both cancer development and cell death, we determined if besides its general cytotoxicity, ABZ could predispose to tumor development. As measured by loss of heterozygosity (LOH) in vitro and in vivo ABZ was found as a potent inducer of LOH and accelerator of chromosomal missegregation.

Apoptosis oxidative damage-mediated and antiproliferative effect of selenylated imidazo[1,2-a]pyridines on hepatocellular carcinoma HepG2 cells and in vivo

Imidazo[1,2-a]pyridines (IP) and organoselenium compounds have been widely exploited in medicinal chemistry due to their pharmacological activities. Hepatocellular carcinoma (HCC) has few treatment options, and unfortunately, the prognosis is poor. Thus, the development of novel therapeutic drugs is urgent. The present study aimed at evaluating the antitumor mechanism of selenylated IP against HepG2 cells and in vivo. The selenylated IP named IP-Se-06 (3-((2-methoxyphenyl)selanyl)-7-methyl-2-phenylimidazol[1,2-a]pyridine) showed high cytotoxicity against HepG2 cells (half-maximal inhibitory concentration [IC₅₀ ] = 0.03 µM) and selectivity for this tumor cell line. At nontoxic concentration, IP-Se-06 decreased the protein levels of Bcl-xL and increased the levels of p53, leading to inhibition of cell proliferation and apoptosis. This compound decreased the level of extracellular signal-regulated kinase 1/2 protein and changed the levels of proteins involved in the drive of the cell cycle, tumor growth, and survival (cyclin B1, cyclin-dependent kinase 2). In addition, IP-Se-06 decreased the number of cells in the S phase. In addition, IP-Se-06 led to increased generation of reactive oxygen species, changed antioxidant defenses, and caused DNA fragmentation. Finally, IP-Se-06 significantly inhibited the growth of Ehrlich ascites tumors in mice, increased survival time, and inhibited angiogenesis. Therefore, IP-Se-06 may be an important compound regarding the development of a therapeutic drug for HCC treatment.

Targeting ROS overgeneration by N-benzyl-2-nitro-1-imidazole-acetamide as a potential therapeutic reposition approach for cancer therapy

BackgroundWe investigated the role of reactive oxygen species (ROS) in the anticancer mechanism of N-benzyl-2-nitro-1-imidazole-acetamide (BZN), a drug used in Chagas' disease treatment. MethodsBALB/c mice, inoculated with Ehrlich ascites carcinoma (EAC), were treated with BZN or BZN + Nacylcysteine (NAC) or NAC for 9 days. Subsequently, the inhibition of tumor growth and angiogenesis as well as animal survival were evaluated. Apoptosis and the cell cycle were evaluated using fluorescence microscopy and flow cytometry, while oxidative stress was evaluated by measuring TBARS content, DNA damage, calcium influx and ROS generation and antioxidant defenses (CAT, SOD, GPx, GST and GR). Immunoblotting was used to evaluate key death and cell cycle proteins. Results BZN treatment inhibited tumor progression (79%), angiogenesis (2.8-fold) and increased animal survival (29%). Moreover, BZN increased ROS levels (42%), calcium influx (55%), TBARS contents (1.9-fold), SOD (4.4-fold), GPx (17.5-fold) and GST (3-fold) activities and GSH depletion (2.5-fold) also caused DNA fragmentation (7.6-fold), increased cleaved PARP and promoted the trapping of cells in the G1 phase, as corroborated by the reduction in cyclin A and increased CDK2 protein levels. In silico DNA and molecular dynamic simulations showed H-bonds and hydrophobic interactions that were confirmed by circular dichroism. Increased apoptosis (232%), induced by treatment with BZN, was demonstrated by apoptotic cell staining and p53 level. Conclusion The current findings indicate that BZN acts as a tumor growth inhibitor and anti-angiogenic agent by ROS overgeneration, which interact with DNA causing damage and triggering apoptosis.

CDK2 and Bcl-xL inhibitory mechanisms by docking simulations and anti-tumor activity from piperine enriched supercritical extract

Supercritical fluid technologies offer an innovative method for food industry and drug discovery from natural sources. The aim of the study is to investigate the anti-tumor activity of piperine rich extract by supercritical fluid (SFE) from black pepper (Piper nigrum). In silico docking simulations predicted anti-tumor molecular mechanism and protein-piperine hydrophobic interactions, showing hydrogen bonds between piperine and residue Ser5 inside the ATP binding site in CDK2. Moreover, piperine interacts with peptide substrate residue Lys8 inside its binding site in Cyclin A molecule. Other predicted interaction showed piperine inside the hydrophobic groove of Bcl-xL. Confirming the docking simulation, in vitro assays with SFE (40 °C/30 MPa) showed cytotoxicity to MCF-7 cells (IC50 = 27.8 ± 6.8 μg/ml) correlated to increased apoptosis. Balb/c mice-bearing Ehrlich Ascites Carcinoma (EAC) group that received the SFE (100 mg/kg/day) showed tumor growth inhibition (60%) and increased mice survival (50%), probably related to cell cycle arrest (G2/M) and increased apoptosis. In vivo treatments with SFE increased the expression of pro-apoptotic proteins (p53 and Bax), inhibited cell cycle proteins (CDK2, Cyclin A) and anti-apoptotic protein (Bcl-xL). Thus, confirming in silico predicted inhibitory interactions. These results clearly showed promising performance of the piperine-rich fraction recovered from black pepper, drawing attention to its use as complementary therapy for cancer.

In vivo antitumor activity of by-products of Passiflora edulis f. flavicarpa Deg. Rich in medium and long chain fatty acids evaluated through oxidative stress markers, cell cycle arrest and apoptosis induction

Antiinflammatory and antitumor activity has been reported in Passiflora edulis (yellow passion fruit) nevertheless the intrinsic mechanisms of action are not fully elucidated. The present study aimeds to perform a comparison between the antitumor activity involving the crude extract (HCE) and the supercritical fluid extract with ethanol as co-solvent (SFEtOH) from P. edulis f. flavicarpa Deg. The in vitro cytotoxicity was evaluated in MCF-7 cells, while the in vivo antitumor activity was assessed in male Balb/c mice inoculated with Ehrlich carcinoma cells. SFEtOH exhibited higher antitumor activity compared to HCE. Wherein, SFEtOH showed an EC₅₀ of 264.6 μg/mL against MCF-7 cells as well as an increased inhibition of tumor growth of 48.5% (p < 0.001) in male Balb/c mice, thereby promoting an increased mice lifespan to approximately 42%. Moreover, SFEtOH caused lipid (p < 0.001) and protein (p < 0.001) oxidation by increasing glutathione redox cycle activity while decreased the thioredoxin reductase activity (p < 0.001). SFEtOH also induced oxidative DNA damage in Ehrlich ascites carcinoma (EAC) cells leading to G2/M cycle arrest and has increased apoptotic cells up to 48.2%. These data suggest that the probable mechanisms of antitumor effect are associated to the lipid, protein and DNA damage, leading to cell cycle arrest and triggering apoptosis via mitochondrial pathway, should be probable due to the presence of medium and long chain fatty acids such as lauric acid.

Albendazole as a promising molecule for tumor control

This work evaluated the antitumor effects of albendazole (ABZ) and its relationship with modulation of oxidative stress and induction of DNA damage. The present results showed that ABZ causes oxidative cleavage on calf-thymus DNA suggesting that this compound can break DNA. ABZ treatment decreased MCF-7 cell viability (EC₅₀=44.9 for 24 h) and inhibited MCF-7 colony formation (~67.5% at 5 μM). Intracellular ROS levels increased with ABZ treatment (~123%). The antioxidant NAC is able to revert the cytotoxic effects, ROS generation and loss of mitochondrial membrane potential of MCF-7 cells treated with ABZ. Ehrlich carcinoma growth was inhibited (~32%) and survival time was elongated (~50%) in animals treated with ABZ. Oxidative biomarkers (TBARS and protein carbonyl levels) and activity of antioxidant enzymes (CAT, SOD and GR) increased, and reduced glutathione (GSH) was depleted in animals treated with ABZ, indicating an oxidative stress condition, leading to a DNA damage causing phosphorylation of histone H2A variant, H2AX, and triggering apoptosis signaling, which was confirmed by increasing Bax/Bcl-xL rate, p53 and Bax expression. We propose that ABZ induces oxidative stress promoting DNA fragmentation and triggering apoptosis and inducing cell death, making this drug a promising leader molecule for development of new antitumor drugs.

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The ABZ redox signaling pathway was examined in cancer inhibition.

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The oxidative stress can explain the ABZ antitumor mechanisms of action.

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The ABZ oxidative stress modulation can be used for cancer therapeutics development.

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ABZ can be used as a molecule prototype in possible drug repositioning.

Biological evaluation of 3-acyl-2-arylamino-1,4-naphthoquinones as inhibitors of Hsp90 chaperoning function

Hsp90 is a chaperone that plays a key function in cancer cells by stabilizing proteins responsible of cell growth and survival. Disruption of the Hsp90 chaperone machinery leads to the proteasomal degradation of its client proteins. Hsp90 appears then as an attractive target for the development of new anticancer molecules. We have shown that ascorbate- driven menadione-redox cycling inhibits Hsp90 activity by provoking an N-terminal cleavage of the protein, inducing the degradation of several of its client proteins. Since the mechanism involves an oxidative stress, we explored the effect of a series of diverse donor-acceptor 3-acyl-2-phenylamino 1,4-naphthoquinones on Hsp90 integrity, in the presence of ascorbate. Results show that quinone-derivatives that bear two electroactive groups (namely quinone and nitro) exhibit the highest inhibitory activity (Hsp90 cleavage and cell death). The biological activity of the series mainly relies on their redox capacity and their lipophilicity, which both modulate the ability of these compounds to induce a cytotoxic effect in K562 cells. As observed with other redox cycling quinones, the protein cleavage is blocked in the presence of N-terminal Hsp90 inhibitors suggesting that the availability or occupancy of nucleotide binding site in the N-terminal pocket of Hsp90 plays a critical role. In addition the survival of cancer cells and their metabolic and redox homeostasis were strongly impaired by the presence of ascorbate. Since these effects were similar to that obtained by ascorbate/menadione and they were blocked by the antioxidant N-acetylcyteine (NAC), it appears that oxidative stress is a major component of this cytotoxicity.

Textile effluents induce biomarkers of acute toxicity, oxidative stress, and genotoxicity

The present work consists of a comparative evaluation of the toxicity of a nonremediated textile effluent (NRTE) with an effluent remediated by a pulverized chitosan system (RCTS) or by a conventional effluent process (remediated biologic and physico-chemical effluent [RBPC]). Acute toxicity assays, oxidative stress biomarkers, physico-chemical parameters, and genotoxicity indices were analyzed to achieve the toxicity of all effluents. After RCTS treatment, approximately 80% of dyes were removed, together with a significant decreased of the metal content, compared with a relatively increase in metal content after RBPC treatment. RBPC and RCTS treatments did not cause acute toxicity to Vibrio fischeri and Artemia sp., whereas RBPC caused acute toxicity to Daphnia magna but RCTS did not. Compared with NRTE, chitosan remediation decreased oxidative stress biomarkers, such as the contents of lipoperoxidation (measured as thiobarbituric acid-reactive substances [TBARS], 29.9%) and the reduced form of glutathione (GSH; 73.5%) levels in D. rerio, whereas animals exposed to RBPC showed enhanced TBARS (57.2%) and decreased GSH concentrations (56.4%). RCTS and RBPC remediation elicited catalase activity induction (161.8% and 127.3%, respectively) compared with NRTE. Accordingly, DNA fragmentation and micronucleus frequency in D. rerio decreased after remediation with RBPC or RCTS compared with NRTE, but RCTS treatment was more effective than RBPC in decreasing genotoxicity (90.5% and 73.8% decrease in DNA fragmentation and 67.8% and 50.4% decrease in micronucleus frequency, respectively). The results indicate that chitosan adsorption system is a useful tool for textile effluent remediation compared with the conventional remediation by biologic and physico-chemical processes.

Use of coal mining waste for the removal of acidity and metal ions Al (III), Fe (III) and Mn (II) in acid mine drainage

The coal industry may generate acid mine drainage (AMD) and mining wastes, which may adversely affect the quality of the environment. In this study we propose the use of this waste in the removal of acidity and metal ions, as well as in the reduction of the toxicity of AMD. A physico-chemical analysis of the waste shows the presence of mainly SiO2, Al2O3 and Fe2O3 and a superficial area of 4.316 m2 g(-1). The treatment of AMD with the waste resulted in an increase in pH from 2.6 to 7.8 and removed 100% of the Al (III), 100% of the Fe (III) and 89% of the Mn (II). We also observed that the high toxicity of the AMD towards Daphnia magna (LC50 = 3.68%) and Artemia sp. (LC50 = 4.97%) was completely eliminated after treatment with the waste. The data obtained allow us to propose that the waste can be used in the treatment of AMD, providing an economic use for the waste.

Evaluation of remediation of coal mining wastewater by chitosan microspheres using biomarkers

Acidic mine waters have a marked influence on the surrounding environment and pose a serious threat through long-term environmental degradation. Therefore, it is important to improve and monitor water quality with the aim of decreasing the hazard presented by this effluent emission. The aim of this work was to evaluate the remediation of mining wastewater effluents by chitosan microspheres using biomarkers of exposure and effect. DNA damage (Comet assay) and several biomarkers of oxidative stress, such as lipoperoxidation levels (TBARS), superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) activities, and contents of reduced glutathione (GSH), were measured in blood and liver of tilapia (Oreochromis niloticus) exposed for 7, 15, and 30 days to dechlorinated tap water, 10% coal mining wastewater (CMW), and coal mining wastewater treated with chitosan microspheres (RCM). The results indicate that hepatic TBARS levels were significantly higher in fish exposed to CMW after 7, 15, and 30 days (100%, 86%, and 63%, respectively), and after remediation there was no significant difference in relation to the control group. Hepatic GSH concentrations were lower than control values for CMW after 7 and 15 days of exposure (34% decrease at both times), and this concentration was normalized by treatment with chitosan. SOD showed increased activity in liver after 15 and 30 days of exposure, 30% and 36%, respectively, and in fish exposed to RCM there was no change in this activity compared with the control group. Increased CAT activity in liver was observed during all experimental periods in fish exposed to CMW (46%, 50%, and 56% at 7, 15, and 30 days, respectively) compared with the control or treated-water groups. The highest increase in hepatic GST activity (106%) was observed only in fish exposed to CMW for 30 days. There was an increase in DNA damage in liver (50% at 7 and 15 days) and blood (79%, 77%, and 48% at 7, 15, and 30 days, respectively) after exposure to CMW. In contrast, the fish exposed to wastewater treated with chitosan microspheres exhibited DNA fragmentation indexes similar to the control group. The results obtained indicate the use of oxidative stress biomarkers as useful tools for the toxicity evaluation of coal mining effluents and also suggest that chitosan microspheres may be used as an alternative approach for remediation of coal mining wastewaters.

Time-course variations of DNA damage and biomarkers of oxidative stress in tilapia (Oreochromis niloticus) exposed to effluents from a swine industry

DNA damage (Comet assay), lipoperoxidation levels (TBARS), and several biomarkers of oxidative stress such as catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), and contents of reduced (GSH) and total (TG) glutathione were measured in liver and blood (Comet assay) of tilapia (Oreochromis niloticus) exposed for 7, 15, 30 (subchronic exposure), 60, and 90 days (chronic exposure) to two treatment lagoons of a swine-processing plant, the first an anaerobic lagoon and the second a final treatment lagoon. After the 15th day, TBARS increased in fish exposed to both lagoons, decreased on the 30th day, and on the 90th day remained similar to controls. Fish exposed subchronically and chronically to both effluents showed consistently greater DNA damage. The CAT and GPx activities showed similar profiles and were induced only during the first week and during the first and second months. GST activity was induced throughout the experimental period. On the other hand, GR activities showed inverted profiles, with progressively decreased activities in the liver of fish exposed to the anaerobic lagoon, and progressively increased activities in fish exposed to the final lagoon. GSH showed higher contents in liver after 60 and 90 days of exposure to the final lagoon. GSSG contents were higher in fish exposed to the final lagoon throughout the experimental period. After 15 days, tilapia exposed to both lagoons showed enhanced total glutathione contents. The hepatic antioxidant system and biomarkers of oxidative stress such as DNA fragmentation and TBARS contents of tilapia exposed to both lagoons presented biphasic profiles. These changes in the antioxidant status also indicate that the industrial treatment is not adequate to avoid damaging environmental effects.

Lipid lowering activity of hydrosoluble chitosan and association withAloe vera L. andBrassica olearaceae L

The lipid lowering activity of chitosan associated with Aloe vera L. or hydrosoluble chitosan with Brassica olearaceae L. has been studied in rats. In this study, rats were submitted to different treatments with hydrosoluble chitosan alone (4% diet), hydrosoluble chitosan associated with Aloe vera L. or hydrosoluble chitosan with Brassica olearaceae L. (1:4, 4% diet) for 35 days, to identify the formula with the highest hypolipaemic potential. The results showed that all treatments reduced blood lipid levels but that hydrosoluble chitosan associated with Brassica olearaceae L. proved most efficient, because it decreased the levels of total cholesterol, LDL-cholesterol, VLDL-cholesterol and triglycerides in blood serum. The overall results suggest that the hydrosoluble chitosan/Brassica olearaceae L. association is a therapeutic alternative for hyperlipidaemia, and in this way may contribute to the prevention of atherogenic processes.

A comparative study of albendazole and mebendazole-induced, time-dependent oxidative stress

Albendazole (ABZ) and mebendazole (MBZ) are two benzimidazole-derived drugs that show remarkable antihelmintic activity and are widely used in the treatment and control of helminths. Some antihelmintic drugs seem to act through the deleterious generation of reactive oxygen and nitrogen species (ROS and RNS, respectively) to which helminths have no, or relatively low, antioxidant defences (AD), when compared to aerobic organisms. The main objective of the present study consisted of the evaluation of the effect of both drugs on the AD and on some oxidative stress indicators in the host liver. Adult, male, Wistar rats were treated with ABZ or MBZ at doses of 40 mg/kg for different periods of time (2, 4, 8 and 10 days). After treatment, the activities of superoxide dismutase, catalase, glutathione reductase, and glutathione S-transferase, as well as the concentrations of TBARS, reduced glutathione, oxidized glutathione and total glutathione, were evaluated in rat hepatocytes. The serum nitrogen monoxide, usually known as nitric oxide (NO) levels, was also measured. The results showed that both drugs provoked an oxidative stress condition, demonstrated through the elevation of TBARS contents and through the decrease of some AD. Moreover, ABZ showed to be a strong ROS and RNS generator while MBZ showed a low and transient effect on ROS generation. It is suggested that MBZ could be the first-choice drug in the treatment of helminthiasis because it shares a similar therapeutic indication with ABZ, and because it causes only a mild oxidative stress to the host.

Use of chitosan microspheres as remedial material for acidity and iron (III) contents of coal mining wastewaters

Chitosan microspheres are highly effective in neutralizing the acidity of wastewaters from coal mining. The saturation capacity for the formation of a superficial monolayer on the adsorbent was interpreted using Langmuir isotherm and considering the amino groups as the adsorption sites for hydronium ions. The saturation capacity of the surface of the static system was 0.428 mol kg(-1), higher than that of the dynamic one. This value corresponds to the neutralization of 135 liters of wastewater per kilogram of microspheres. One gram of chitosan microspheres was capable of increasing wastewater pH from 2.5 to 4.0 and removing approximately 100% of its iron (III) contents.

Remediation of coal mining wastewaters using chitosan microspheres

This study aimed to evaluate the potential use of chitosan and chitosan/poly(vinylalcohol) microspheres incorporating with tetrasulphonated copper (II) phthalocyanine (CTS/PVA/TCP) in the remediation of coal mining wastewaters. The process was monitored by toxicity tests both before and after adsorption treatments with chitosan and microspheres. Physicochemical parameters, including pH and trace-metal concentration, as well as bioindicators of water pollution were used to that end. Wastewater samples colleted from drainage of underground coal mines, decantation pools, and contaminated rivers were scrutinized. Acute toxicity tests were performed using the Brine Shrimp Test (BST) in order to evaluate the remediation efficiency of different treatments. The results showed that the pH of treated wastewater samples were improved to values close to neutrality. Chitosan treatments were also effective in removing trace-metals. Pre-treatment with chitosan followed by microsphere treatment (CTS/PVA/TCP) was more effective in decreasing toxicity than the treatment using only chitosan. This was probably due to the elimination of pollutants other than trace-metals. Thus, the use of chitosan and microspheres is an adequate alternative towards remediation of water pollution from coal mining.

Hypolipidaemic activity of methanol extract of Aleurites moluccana

The lipid-lowering action of the leaves of the Aleurites moluccana methanol extract was studied in Triton W-1339 and high-fat-diet fed rats. The serum lipids (total cholesterol, LDL- and HDL-cholesterol and triglycerides) and body weight were found to be lowered by A. moluccana (300 mg/kg, b.w.) in rats with Triton-induced hypercholesterolaemia and on a hyperlipaemic diet. The results suggest that the lipid lowering action of this natural product is mediated through inhibition of hepatic cholesterol biosynthesis and reduction of lipid absorption in the intestine.

Time-dependent oxidative stress caused by benznidazole

Benznidazole (BZN) is a nitroimidazole derivative which has a notable trypanocide activity, and it is the only drug used in Brazil and Argentina for the treatment of Chagas' disease. The drug in current use is thought to act, at least in part, by inducing oxidative stress within the parasite. Imidazolic compounds are involved in the production of reactive oxygen species (ROS). In order to evaluate the effect of BZN on ROS production and on the antioxidant status of the host, male rats were treated for different periods of time (2, 4, 6, 10 and 30 days) with 40 mg BZN/kg body weight. After treatment, biomarkers of oxidative stress such as the activities of catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST) and glutathione reductase (GR), and also thiobarbituric acid reactive species (TBARS), reduced glutathione (GSH), total glutathione (TG) and oxidized glutathione (GSSG) concentrations, were measured in crude hepatic homogenates. Our results revealed that BZN is able to cause tissue damage as shown by increased TBARS content, inhibition of some antioxidants and induction of other antioxidants in a concentration- and time-dependent manner. The tissue damage measured as TBARS increased up to the 10th day of treatment. GST activity was inhibited during the BZN treatment. On the other hand, CAT and GR showed similar increased activities at the beginning, followed by decreased activities at the end of the treatment. After 30 days of treatment, GR activity remained low while CAT activity was high, compared to controls. The SOD activities remained unchanged throughout the experimental period. GSH showed lower values at the beginning of BZN treatment but the hepatic concentrations were enhanced at the end of the experimental period. Total glutathione showed a similar profile, and oxidized glutathione showed higher values in rats treated with BZN. In conclusion, these results indicate that, at therapeutic doses, BZN treatment elicits an oxidative stress in rat hepatocytes.

Influence of season and pollution on the antioxidant defenses of the cichlid fish acará (Geophagus brasiliensis)

The livers of Geophagus brasiliensis collected from both a non-polluted site and a polluted site were analyzed for different antioxidant defenses, O2 consumption, thiobarbituric acid-reactive substance (TBARS) levels, and histological damage. Compared to controls (116.6 +/- 26.1 nmol g-1), TBARS levels were enhanced at the polluted site (284.2 +/- 25.6 nmol g-1), as also was oxygen consumption (86.6 +/- 11.3 and 128.5 +/- 9.8 micromol O2 min-1 g-1, respectively). With respect to enzymatic antioxidants, increased catalase activities (8.7 +/- 1.3 and 29.2 +/- 2.4 mmol min-1 g-1, respectively), unchanged superoxide dismutase activities (767.2 +/- 113.3 and 563.3 +/- 70.2 U g-1, respectively), and diminished glutathione S-transferase activities (29.0 +/- 3.2 and 14.9 +/- 3.2 micromol min-1 g-1, respectively) were detected. Reduced glutathione (1.91 +/- 0.17 and 1.37 +/- 0.25 mM, respectively), oxidized glutathione (1.50 +/- 0.20 and 0.73 +/- 0.17 mM, respectively), and total glutathione (3.40 +/- 0.26 and 2.07 +/- 0.27 mM, respectively) concentrations were also below control values at the polluted site. Nevertheless, the observed ethoxyresorufin-O-deethylase activities (1.34 +/- 0.11 and 16.7 +/- 0.21 pmol min-1 mg-1, respectively) showed enhanced values at the polluted site. The main histological damage observed in the hepatocytes from fish collected at the polluted site was characterized by heavy lipid infiltration. Fish collected at the end of spring showed higher O2 consumption, higher superoxide dismutase and glutathione S-transferase activities, and higher total and oxidized glutathione concentrations compared to the beginning of autumn. No seasonal changes were observed in catalase activities, glutathione or TBARS levels. Fish chronically exposed to relatively high pollution levels seem to be unable to set up adequate antioxidant defenses, probably due to severe injury to their hepatocytes. The higher antioxidant defenses found at the end of spring are probably related to the enhanced activities during high temperature periods in thermoconforming organisms.

Gas exchange during exercise in different evolutional stages of chronic Chagas' heart disease

OBJECTIVE

To compare gas exchange at rest and during exercise in patients with chronic Chagas' heart disease grouped according to the Los Andes clinical hemodynamic classification.

METHODS

We studied 15 healthy volunteers and 52 patients grouped according to the Los Andes clinical and hemodynamic classification as follows: 17 patients in group IA (normal electrocardiogram and echocardiogram), 9 patients in group IB (normal electrocardiogram and abnormal echocardiogram), 14 patients in group II (abnormal electrocardiogram and echocardiogram, without congestive heart failure), and 12 patients in group III (abnormal electrocardiogram and echocardiogram with congestive heart failure). The following variables were analyzed: oxygen consumption (V O2), carbon dioxide production (V CO2), gas exchange rate (R), inspiratory current volume (V IC), expiratory current volume (V EC), respiratory frequency, minute volume (V E), heart rate (HR), maximum load, O2 pulse, and ventilatory anaerobic threshold (AT).

RESULTS

When compared with the healthy group, patients in groups II and III showed significant changes in the following variables: V O2 peak, V CO2 peak, V IC peak, V EC peak, E, HR, and maximum load. Group IA showed significantly better results for these same variables as compared with group III.

CONCLUSION

The functional capacity of patients in the initial phase of chronic Chagas' heart disease is higher than that of patients in an advanced phase and shows a decrease that follows the loss in cardiac-hemodynamic performance.

Liberação controlada da eosina impregnada em microesferas de copolímero de quitosana e poli(ácido acrílico)

Microesferas de quitosana com grau de desacetilação médio de 85,6% foram enxertadas com poli(ácido acrílico) para aplicação como sistemas de liberação controlada de fármacos. O corante eosina impregnado nas microesferas de quitosana modificada foi utilizado como marcador para estudo in vitro de liberação de fármacos. As microesferas de quitosana foram obtidas pelo método de inversão de fases com NaOH, seguidas de reticulação com glutaraldeído, redução com cianoboroidreto de sódio e enxertia com poli(ácido acrílico) na presença de uma solução de nitrato de cério (IV) amoniacal como iniciador redox. Os estudos in vitro de liberação da eosina a partir de microesferas de quitosana, mostraram que o corante foi liberado em função do tempo a pH 6,8 e 9,8 que simulam as condições fisiológicas do trato gastrointestinal, enquanto que nenhuma eosina foi liberada a pH 1,2.

Sera from chronic chagasic patients depress cardiac electrogenesis and conduction

We report results obtained with sera from 58 chronic chagasic patients that were evaluated for effects on heart rate and atrioventricular (AV) conduction in isolated rabbit hearts and screened for the presence of muscarinic and beta-adrenergic activity. We show that sera from 26 patients decreased heart rate, while 10 increased it and 22 had no effect. Additionally, sera from 20 of the 58 patients blocked AV conduction. Muscarinic activation seems to be involved in both effects, but is not the only mechanism, since atropine did not antagonize the decrease in heart rate in 23% of sera or AV block in 40%. Sera from patients with complex arrhythmias were significantly more effective in depressing both heart rate and AV conduction. Sera that induce increases in heart rate seem to operate exclusively through beta-adrenergic activation. Two of these sera, evaluated with respect to intercellular communication in primary cultures of embryonic cardiomyocytes were able to block gap junction conductance evaluated by a dye injection technique after 24-h exposure. The mechanisms underlying this uncoupling effect are currently being investigated.

Presence of antibodies against the third intracellular loop of the m2 muscarinic receptor in the sera of chronic chagasic patients

Patients in the chronic phase of Chagas' disease suffer from a slowly evolving inflammatory cardiomyopathy that can lead to severe cardiac dilatation, congestive heart failure, and death. This process appears to be caused by autoimmune recognition of heart tissue by a mononuclear cell infiltrate decades after infection with the parasite Trypanosoma cruzi. Recent evidence suggests that there are circulating antibodies in chronic chagasic patients that alter the physiological behavior of the heart on binding to G-protein-coupled cardiovascular receptors, including beta1-adrenergic and m2 muscarinic receptors. A 42 kDa fusion protein was constructed that contains the central part of the third intracellular loop (i3; Arg(267)-Arg(381)) of the human m2 muscarinic receptor, linked to glutathione S-transferase. This fusion protein was overexpressed in Escherichia coli and subsequently purified by affinity chromatography. Based on Western blots, the i3 loop is specifically recognized by the sera of chronic chagasic patients who have reached advanced stages of cardiac failure (according to the Los Andes classification). Analysis of the prevalence and distribution of these antibodies shows a strong association between seropositive patients and moderate (group II) to severe (group III) heart dysfunction.

Saliva ELISA: a method for the diagnosis of chronic Chagas disease in endemic areas

An indirect enzyme linked immunosorbent assay (ELISA) was applied to saliva to detect chronic infection by Trypanosoma cruzi in humans. Saliva samples from 114 Chagas' disease chronically infected individuals, characterized by three serological tests and clinical evaluation and from 100 healthy controls were tested for T. cruzi specific IgG antibodies. At dilution of 1 in 2, specific antibodies were detected in saliva samples from 103 of 114 samples from infected patients and 5 of 100 controls (sensitivity 90.4%, specificity 95%). There was no significant correlation between the antibody titre and cardiac or gastrointestinal tract disease. This assay possesses some advantages over other methods as saliva collection is non-invasive, requires no special equipment and whole saliva gave reproducible results. Although serology remains the gold standard for T. cruzi infection, these results suggest that T. cruzi specific salivary antibody detection may provide a screening diagnostic test and contribute to epidemiological studies of chronic trypanosomiasis infection in endemic areas.

Functionally active cardiac antibodies in chronic Chagas' disease are specifically blocked by Trypanosoma cruzi antigens

Antibodies of chronic chagasic patients have been shown to interfere with electric and mechanical activities of cardiac embryonic myocytes in culture and with whole mammalian hearts. A mechanism proposed for this effect involves interaction of the antibodies with G-protein-linked membrane receptors, thus leading to activation of beta adrenergic and muscarinic receptors; more specifically, IgG of chagasic patients would interact with the negatively charged regions of the second extracellular loop of these receptors. We performed competition experiments to test this hypothesis. We evaluated the effect of sera/IgG from patients previously known to depress electrogenesis and/or atrioventricular conduction in isolated rabbit hearts after incubation with live and lysed parasites, the peptide corresponding to the second extracellular loop (O2) of the M2 receptor, and different peptides derived from two ribosomal proteins of T. cruzi: P0 and P2beta. Our results indicate that 1) the antigenic factor inducing the functionally active IgGs in the chagasic patients is probably an intracellular T. cruzi antigen; 2) IgG/serum is interacting with the O2 region of the M2 receptor in the rabbit heart; and 3) the negative charges present in the ribosomal proteins of T. cruzi are important in mediating the interaction between the patients' serum/IgG and the receptor.

Sera from chronic chagasic patients with complex cardiac arrhythmias depress electrogenesis and conduction in isolated rabbit hearts

BACKGROUND

Immune dysfunction has long been proposed as a mechanism for the etiopathogenesis of the chronic phase of Chagas' disease. Antibodies of chagasic patients have been shown to interfere with electric and mechanical activity of embryonic myocardial cells in culture. Here, we demonstrate that antibodies derived from a group of chronic chagasic patients are able to induce disturbances in the electrogenesis and conduction in isolated adult rabbit hearts.

METHODS AND RESULTS

Sera from chronic chagasic patients with complex cardiac arrhythmias (ChA+) decreased heart rate (from 131+/-26 to 98+/-37 bpm [mean+/-SD]; n=6; P<.05) in isolated rabbit hearts when perfused at a dilution of 1:100 (vol:vol) by the Langendorff method. Sera from another experimental group of four chronic chagasic patients without complex arrhythmias (ChA-) and two control groups composed of five Wolff-Parkinson-White (WPW) syndrome patients and five orthopedic surgery patients did not affect heart rate when tested under similar conditions. In addition, sera from five of six ChA+ patients and from one WPW patient induced AV conduction blockade. Effects of the sera from ChA+ patients are due to their IgG fractions. Both serum and IgG effects are blocked by atropine (10 micromol/L).

CONCLUSIONS

Antibodies of ChA+ patients decrease heart rate and induce AV conduction block in isolated adult rabbit hearts through activation of muscarinic receptors.

[Anaerobic threshold detected using "V-slope analysis" in chronic chagasic disease]

Anaerobic threshold (AT) as measured by V-slope, is the best parameter of cardiac reserve in patients with heart failure. A reduction of AT reflects linearly a limited cardiopulmonary reserve in patients with heart disease. We measured the anaerobic threshold from 28 patients (18 men; age 47 +/- 6.7 years) classified into four groups: IA (normal ECG, without heart disease; 9 patients); IB (normal ECG, early left ventricular segmental abnormalities; 5 patients); II (abnormal ECG, advanced myocardial damage, no signs of heart failure, 7 patients); and III (abnormal ECG, end-stage, congestive heart failure; 7 patients). The analysis of variance indicated that the anaerobic threshold from patients of group LA was significantly greater than in groups IB, II and III (p = 0.001). Tukeys multiple comparison test showed no significative differences between mean AT in groups IB, II and III. The present study clearly demonstrates that occurrence of initial left ventricular contraction abnormalities is associated with definite reduction of cardiopulmonary reserve, and that this reduction is progressive and parallels the hemodynamic alterations. The most probable cause of this finding in group IB is diastolic dysfunction as clearly shown in echocardiogram.

[The proliferative response of T cells against cruzipain in chronic chagasic cardiopathy]

In this paper, we sought to determine if chronic chagasic patients with cardiopathy could be distinguished from those displaying non-chagasic cardiopathy on the basis of T cell proliferative responses to cruzipain (GP57/51), a major antigen of T. cruzi. Assays were performed with peripheral blood mononuclear cells from 24 individuals classified as follows: normal donors (n = 8), patients with non-chagasic cardiopathy (n = 8), patients with chronic chagasic cardiopathy without morbid associations (n = 8). The analysis of variance indicated that the proliferative responses stimulated by cruzipain were significantly higher in the group of chagasic patients (p = 0.0001). Turkey's multiple comparison test showed that the proliferative index medium from normal and non-chagasic cardiopathy was not significantly different from each other. We conclude that the T cell responses against T. cruzipain, as measured by proliferative indices of cells found in peripheral blood, are exclusively associated with Chagas, disease. In view of the abundance of cruzipain antigen in amastigotes it is possible that these T cell specificities contribute to the heart tissue damage observed in chronic Chagas, disease patients.

Analysis and partial epitope mapping of human T cell responses to Trypanosoma cruzi cysteinyl proteinase

Human infection with Trypanosoma cruzi (Chagas' disease) is usually accompanied by humoral and cellular immune responses to GP57/51, a major antigen that was recently identified as a prominent cysteinyl proteinase (cruzipain). The PBMC responses of 11 chronic chagasic patients and the properties of anti-cruzipain T cell lines are reported herein. GP57/51, isolated from Y strain epimastigotes (n-cruzipain) or the recombinant protein expressed in E. coli (r-cruzipain), elicited proliferative responses of variable intensity from the patient's PBMC. T cell lines were then generated using each of these antigens. These lines, which always carried the CD4+ phenotype, were reciprocally stimulated by n-cruzipain or r-cruzipain, the responses to the former being usually stronger. The analysis of cytokine production suggested that Th1-like subsets dominate the patient's responses: IFN-gamma was consistently induced on stimulation with either n-cruzipain or r-cruzipain. In contrast, IL-4 was present in very small concentrations or was undetectable. We then sought to define T cell epitopes of cruzipain using synthetic peptides spanning portions of the central (catalytic) domain and COOH-terminal extension. From a panel of 11 peptides, only one 33 mer peptide (P214) elicited a strong proliferative response on anti-cruzipain T cell lines, the intensity being comparable to that induced by r-cruzipain. Conversely, T cell lines started with P214 were responsive to either n-cruzipain or r-cruzipain, the proliferative responses again being accompanied by IFN-gamma production, but not IL-4. Interestingly, P214 is located in a conserved region of the catalytic domain of cruzipain, hence may propitiate opportunities for cross-recognition of other members of the papain superfamily. Fine epitope mapping should reveal whether structurally similar regions of host thiol-cathepsins can be potential targets for cross-reactive T cell responses during chronic human infection.

Analysis and partial epitope mapping of human T cell responses to Trypanosoma cruzi cysteinyl proteinase

Human infection with Trypanosoma cruzi (Chagas' disease) is usually accompanied by humoral and cellular immune responses to GP57/51, a major antigen that was recently identified as a prominent cysteinyl proteinase (cruzipain). The PBMC responses of 11 chronic chagasic patients and the properties of anti-cruzipain T cell lines are reported herein. GP57/51, isolated from Y strain epimastigotes (n-cruzipain) or the recombinant protein expressed in E. coli (r-cruzipain), elicited proliferative responses of variable intensity from the patient's PBMC. T cell lines were then generated using each of these antigens. These lines, which always carried the CD4+ phenotype, were reciprocally stimulated by n-cruzipain or r-cruzipain, the responses to the former being usually stronger. The analysis of cytokine production suggested that Th1-like subsets dominate the patient's responses: IFN-gamma was consistently induced on stimulation with either n-cruzipain or r-cruzipain. In contrast, IL-4 was present in very small concentrations or was undetectable. We then sought to define T cell epitopes of cruzipain using synthetic peptides spanning portions of the central (catalytic) domain and COOH-terminal extension. From a panel of 11 peptides, only one 33 mer peptide (P214) elicited a strong proliferative response on anti-cruzipain T cell lines, the intensity being comparable to that induced by r-cruzipain. Conversely, T cell lines started with P214 were responsive to either n-cruzipain or r-cruzipain, the proliferative responses again being accompanied by IFN-gamma production, but not IL-4. Interestingly, P214 is located in a conserved region of the catalytic domain of cruzipain, hence may propitiate opportunities for cross-recognition of other members of the papain superfamily. Fine epitope mapping should reveal whether structurally similar regions of host thiol-cathepsins can be potential targets for cross-reactive T cell responses during chronic human infection.

[A longitudinal electrocardiogram study of Chagas' disease from the acute phase]

Several studies have been done to analyse the relationship between the characteristics of the electrocardiogram (ECG) and mortality in the several stages of the disease, using different methods like multiple case and longitudinal studies. We analysed the ECG from the acute stage up to twenty years of follow-up (+/- 9 years) in 42 patients with Chagas' disease to determine their evolution and it's value like an index for therapeutic evaluation. The 42 patients (18 female, 24 males) were originally from the north of the State of Minas Gerais (Brazil) and the initial stage was mainly in the first two decades of age. All bad cardiac involvement and received full specific treatment. We utilized the following criteria for the ECG analyses: Modified Minnesota Code for Chagas' disease; WHO/ISFC TASK FORCE for inter ventricular conduction disturbances and Pieretti criteria for inactive electrical areas. We conclude that: a) The electrocardiogram changes tend to get worse with evolution into the chronic stage; b) The electrocardiogram is not a good index for therapeutic valuation.

Double-blind therapeutical evaluation based on the quantitative oogram technique, comparing praziquantel and oxamniquine in human schistosomiasis mansoni

Um total de 54 pacientes adultos, com esquistossomose mansônica crônica, nas formas intestinal ou hepatintestinal, participou de um ensaio clínico duplo-cego, para comparar o praziquantel com a oxamniquine. De acordo com uma distribuição aleatória, 27 casos receberam o praziquantel (65 mg/kg de peso corporal) e 27 a oxamniquine (18 mg/kg), administrados em dose oral única. A incidência, intensidade e duração dos efeitos colaterais foram similares para os dois medicamentos A avaliação da eficácia terapêutica baseou se na técnica do oograma quantitativo por biópsia da mucosa retal, realizada ao final de um, dois, quatro e seis meses depois do tratamento. Nessas mesmas ocasiões foram feitos exames de fezes pelos métodos de HOFFMAN, PONS e JANER e de KATO-KATZ, com a finalidade de confrontar seu resultados com os achados do oograma. Para averiguar o efeito imediato do tratamento sobre a atividade ovipositora do parasito, um número restrito de pacientes foi submetido a biópsias retáis no 6,° e 18.° dias subsequentes a administração da medicação. Ambas as drogas provaram ser ativas contra o esquistossoma, vez que os respectivos coeficientes de variação, determinados a partir de oogramas efetuados imediatamente após o tratamento, foram superiores a 60%. Ademais, dentre os 27 pacientes de cada grupo, 24 tratados com praziquantel e 22 com oxamniquine completaram o período de seis meses, requerido para controle parasitológico. Os índices de cura, segundo os achados do oograma e dos exames de fezes pelos métodos de HPJ e KK, foram, respectivamente, 29%,— 50% e 92% com o praziquantel; 23%, 50% e 86% com a oxamniquine. Apesar do baixo percentual de cura, observou-se nos oogramas pós tratamento, uma pronunciada queda no número de ovos vivos por grama de tecido. Esses resultados revelam que ambas as drogas foram semelhantemente eficazes, embora já se tenha comprovado que a susceptibilidade do S. mansoni não seja sempre igual para cada um desses medicamentos, pois linhagens resistentes à oxamniquine evidenciaram ser 100% sensíveis ao praziquantel. Por outro lado, constatou-se uma nítida diferença nos percentuais de cura em função do método utilizado para controle parasitológico. O oograma foi o mais preciso, seguido pelo HPJ e, finalmente, pelo K-K. Tendo ocorrido uma correlação direta entre o número de ovos vivos no oograma e a positividade dos exames de fezes, a percentagem de resultados falso-negativos aumentou acentuadamente após o tratamento, alcançando 47,3% com o HPJ e 92,9% com o K-K. Antes da medicação esses índices eram, respectivamente, 0% e 64,8%. Os autores depreendem que a diferença de precisão da metodologia aplicada para avaliar a eficácia terapêutica pode explicar a divergência encontrada entre o índice de cura obtido neste - ensaio clínico e os relatados por outros investigadores, tanto com o praziquantel quanto com a oxamniquine.