Parasitism of a capybara (Hydrochoerus hydrochaeris) by Amblyomma nodosum Neumann, 1899 and Amblyomma humerale Koch, 1844 in an Amazon forest area, Rondônia, Brazil / [Parasitismo por Amblyomma nodosum Neumann, 1899 e Amblyomma humerale Koch, 1844 em capivara (Hydrochoerus hydrochaeris) em área de Floresta Amazônica, Rondônia, Brasil]

Dois carrapatos adultos, sendo um Amblyomma nodosum e um Amblyomma humerale foram encontrados parasitando ativamente uma capivara (Hydrochoerus hydrochaeris) proveniente da região central do estado de Rondônia, Brasil, na zona rural do município de Ji-Paraná, localizado na Amazônia ocidental. Poucos trabalhos científicos relatam a presença de A. humerale em capivaras. Assim, esta é a primeira vez que A. nodosum é relatado parasitando essa espécie animal. Por não se tratar de um hospedeiro animal conhecido para A. nodosum ou comum para A. humerale, esses achados podem sugerir uma nova relação entre hospedeiros para eles. Portanto, são necessários mais estudos acerca da ecologia desses parasitas, principalmente por serem potenciais transmissores de patógenos de importância em medicina veterinária e saúde pública.(AU)

Environmental impact of biogenic silver nanoparticles in soil and aquatic organisms.

Synthetic silver nanoparticles (AgNPs) are being extensively used in our daily lives; however, they may also pose a risk to public health and environment. Nowadays, biological AgNPs are considered an excellent alternative, since their synthesis occurs by a green technology of low cost and easy scaling. However, studies with these biological nanomaterials (NM) are still limited. Thus, a more careful assessment of their industrial application, economic feasibility and ecotoxicological impacts is crucial. The aim of this study was to investigate the effects of different concentrations of mangrove fungus Aspergillus tubingensis AgNPs on the aerobic heterotrophs soil microorganisms, rice seeds (Oryza sativa) and zebrafish (Danio rerio). Biogenic AgNPs were less harmful for soil microbiota compared to AgNO3. On rice seeds, the AgNPs displayed a dose-dependent inhibitory effect on germination and their subsequent growth and development. The percentage of inhibition of rice seed germination was 30, 69 and 80% for 0.01, 0.1 and 0.5 mM AgNPs, respectively. After 24 h of AgNPs exposition at a limit concentration of 0.2 mM, it did not induce mortality of the zebrafish D. rerio. Overall, A. tubingensis AgNPs can be considered as a suitable alternative to synthetic nanoparticles.

Experimental sepsis induces sustained inflammation and acetylcholinesterase activity impairment in the hypothalamus.

Sepsis is one of the leading causes of mortality in intensive care units besides causing profound alterations in the brain. One of the structures notably affected during sepsis is the hypothalamus, resulting in important physiopathological consequences. Recently, we provided evidence that the presence of neuroinflammation, oxidative stress, and apoptosis in the hypothalamus of septic rats, is accompanied by impairment of arginine vasopressin (AVP) secretion. We had also demonstrated that sepsis survivor animals present attenuated AVP secretion after osmotic challenge, suggesting a persistent inflammation in the hypothalamus. However, the long-term course of inflammation in the hypothalamus remains unclear. Thus, we induced sepsis by cecal ligation and puncture (CLP) in Wistar rats and, five days after sepsis induction, the hypothalamus of each animal was collected for analysis. Nonmanipulated animals (naive) were used as controls. We found that CLP-induced morphological alterations in microglial cells are accompanied by an increase in Iba-1 immunoreactivity. Moreover, we observed enhanced expression of NF-κB and CREB transcription factors, which are well known to modulate the immune response. Additionally, we found that phosphorylation of GSK3α/ß (a kinase upstream to the CREB signaling pathway) was increased, as well as COX-2, iNOS, and IL-6 that are canonic inflammatory proteins. Thus, our results indicated the presence of sustained activation of resident glial cells that may result in neuroinflammation and cholinergic neurotransmission disruptions in the hypothalamus.

BDE-99 congener induces cell death by apoptosis of human hepatoblastoma cell line - HepG2.

Polybrominated Diphenyl Ethers (PBDEs) are an important class of flame retardants with a wide range of toxic effects on biotic and abiotic systems. The toxic mechanisms of PBDEs are still not completely understood because there are several different congeners with different chemical and biological characteristics. BDE-99 is one of these, widely found in the environment and biological samples, showing evidence of neurotoxic and endocrine disruption activities, but with little information about its action mechanism described in the current literature. This work investigated the effects of BDE-99 on the HepG2 cell line in order to clarify its toxic mechanism, using concentrations of 0.5-25 µM (24 and 48 h). Our results showed that BDE-99 could cause cell death in the higher concentrations, its activity being related to a decrease in mitochondrial membrane potential and an accumulation of ROS. It was also shown that BDE-99 induced the exposure of phosphatidylserine, caspases 3 and 9 activation and DNA fragmentation in HepG2 cells, without causing the release of LDH. Thus it was shown that BDE-99 could cause HepG2 cell death by apoptosis, suggesting its toxicity to the human liver.

Evaluation of the mutagenic activity of chrysin, a flavonoid inhibitor of the aromatization process.

Chrysin is one of the natural flavonoids present in plants, and large amounts are present in honey and propolis. In addition to anticancer, antioxidation, and anti-inflammatory activities, chrysin has also been reported to be an inhibitor of aromatase, an enzyme converting testosterone into estrogen. The present study evaluated the mutagenicity of this flavonoid using micronucleus (MN) with HepG2 cells and Salmonella. Cell survival after exposure to different concentrations of chrysin was also determined using sulforhodamine B (SRB) colorimetric assay in HepG2 cells and the influence of this flavonoid on growth of cells in relation to the cell cycle and apoptosis. The MN test showed that from 1 to 15 µM of this flavonoid mutagenic activity was noted in HepG2 cells. The Salmonella assay demonstrated a positive response to the TA100 Salmonella strain in the presence or absence of S9, suggesting that this compound acted on DNA, inducing base pair substitution before or after metabolism via cytochrome P-450. The SRB assay illustrated that chrysin promoted growth inhibition of HepG2 cells in both periods studied (24 and 48 h). After 24 h of exposure it was noted that the most significant results were obtained with a concentration of 50 µM, resulting in 83% inhibition and SubG0 percentage of 12%. After 48 h of incubation cell proliferation inhibition rates (97% at 50 µM) were significantly higher. Our results showed that chrysin is a mutagenic and cytotoxic compound in cultured human HepG2 cells and Salmonella typhimurium. Although it is widely accepted that flavonoids are substances beneficial to health, one must evaluate the risk versus benefit relationship and concentrations of these substances to which an individual may be exposed.

Cytotoxicity, antitumoral and antimycobacterial activity of tetrazole and oxadiazole derivatives.

In this study, the antimycobacterial activity of mono and di-substituted tetrazole and oxadiazole derivatives and their precursors was assayed on Mycobacterium tuberculosis H37Rv, and cytotoxicity was evaluated on J774 macrophages and on tumoral cell lines. Structure Activity Relationship (SAR) analysis was performed using Principal Component Analysis (PCA) to determine the relationship between these compounds and their biological activities.

Trypanocidal activity of 2-propen-1-amine derivatives on trypomastigotes culture and in animal model.

The cis and trans isomers (either E or Z isomers) of the unsubstituted and bromo-2-propen-1-amine derivatives were evaluated in vitro on Trypanosoma cruzi. The results showed that cis is the most active isomeric form against trypomastigote forms of T. cruzi, indicating that it may contribute most to the trypanocidal effect. All mice which received 5 mg kg(-1) daily for 9 consecutive days, or 200 mg kg(-1) in a single dose of the bromo derivative of 2-propen-1-amine, survived after an infection with 10(4) trypomastigotes/ml of the Y-strain of T. cruzi. They also had a significantly lower parasitemia than the controls. However, with 100 mg kg(-1) of benznidazol for 9 consecutive days, 25% of the animals died by the end of the evaluation 40 days after infection. The involvement of the biosynthesis of ergosterol in the trypanocidal effect of the unsubstituted 2-propen-1-amine derivative was investigated on proliferative epimastigote forms of the parasite. The chromatographic analyses of the lipid extracts obtained from parasites treated with 2-propen-1-amine derivatives and controls (not treated) revealed that growth inhibition is correlated with the accumulation of squalene and the decrease of ergosterol levels. These results suggest that inhibition of the biosynthesis of ergosterol is an important target for the action of the 2-propen-1-amine derivative on T. cruzi through the inhibition of the enzyme squalene epoxidase.

Immunotherapy with plasmid DNA encoding mycobacterial hsp65 in association with chemotherapy is a more rapid and efficient form of treatment for tuberculosis in mice.

Tuberculosis (TB) remains a threat for public health, killing around 3 million people a year. Despite the fact that most cases can be cured with antibiotics, the treatment is long and patients relapse if chemotherapy is not continued for at least 6 months. Thus, a better characterization of the working principles of the immune system in TB and identification of new immunotherapeutic products for the development of shorter regimens of treatment are essential to achieve an effective management of this disease. In the present work, we demonstrate that immunotherapy with a plasmid DNA encoding the Mycobacterium leprae 65 kDa heat-shock protein (hsp65) in order to boost the efficiency of the immune system, is a valuable adjunct to antibacterial chemotherapy to shorten the duration of treatment, improve the treatment of latent TB infection and be effective against multidrug-resistant bacilli (MDR-TB). We also showed that the use of DNA-hsp65 alone or in combination with other drugs influence the pathway of the immune response or other types of inflammatory responses and should augment our ability to alter the course of immune response/inflammation as needed, evidencing an important target for immunization or drug intervention.

2-propen-1-amine derivatives and their synthetic intermediates: activity against pathogenic trypanosomatids.

The potential activity of three new derivatives of 3-(4'-Y-[1,1'-biphenyl]-4-yl)-3-(4-X-phenyl)-N,N-dimethyl-2-propen-1-amine (2-PAMs) was assayed against Trypanosoma cruzi and Leishmania amazonensis. They showed higher activity against trypomastigotes and epimastigotes of T. cruzi than the standard drugs, crystal violet and nifurtimox. Besides these derivatives, a series of eleven 2-PAMs derivatives and the corresponding intermediates, biphenyl methanones (BPMs) were assayed against promastigotes of L. amazonensis, showing that the 2-PAMs were remarkably more active than the BPMs. The PAMs 2c, 2e and 2j were about 2-fold more active that pentamidine isothionate and between 27.2- and 46.4-fold less toxic to V79 mammalian cells. The present results encourage further studies, especially against intracellular parasites and in experimental animals.

Lafoensia pacari extract inhibits IL-5 production in toxocariasis.

Toxocariasis is an infection induced by Toxocara canis, an intestinal parasite of dogs. In this study, an experimental murine model of toxocariasis was used to evaluate the anti-inflammatory activity of an ethanolic extract of Lafoensia pacari stem bark. Mice infected with T. canis were treated with L. pacari extract (200 mg/kg, p.o.). Subsequently, we observed a reduction in the number of eosinophils in the peritoneal cavity, bronchoalveolar fluid, blood and bone marrow. Production of interleukin (IL)-5, a major cytokine involved in eosinophilic differentiation, proliferation and activation, is also an important marker for infection. The reduced levels of IL-5 observed in serum, lung homogenates and bronchoalveolar fluid demonstrated the anti-inflammatory mechanisms of L. pacari. Larvae recovery from infected mice treated with L. pacari was comparable with that from untreated mice, suggesting that L. pacari is not toxic to the parasite. Nonetheless, our results demonstrate a potential therapeutic effect of L. pacari extract in IL-5-mediated inflammatory diseases and provide new prospects for the development of drugs to treat IL-5-dependent allergic diseases such as parasite infection and asthma.

Synthesis, antimycobacterial activities and cytotoxicity on V79 of 3-[4'-Y-(1,1'-biphenyl)-4-yl]-N,N-dimethyl-3-(4-X-phenyl)-2-propen-1-amine derivatives.

The derivatives of 3-(4'-bromo-[1,1'-biphenyl]-4-yl)-3-(4-X-phenyl)-N,N-dimethyl-2-propen-1-amine (5a-m) were synthesised through a Friedel-Crafts acylation followed by Wittig reaction. The effects of the compounds on standard strains of Mycobacterium sp. (ATCC) and M. tuberculosis isolated from clinical specimens were evaluated. Also the toxicity was determined on V79 cells line using neutral red uptake (NRU), nucleic acid content (NAC) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction to measure the cellular viability.

Cytotoxic T cells and mycobacteria.

How the immune system kills Mycobacterium tuberculosis is still a puzzle. The classical picture of killing due to phagocytosis by activated macrophages may be only partly correct. Based on recent evidence, we express here the view that cytotoxic T lymphocytes also make an important contribution and suggest that DNA vaccines might be a good way to enhance this.

Antimycobacterial activity of 4'-bromo-[1,1'-biphenyl]-4-yl 4-x-phenylmethanone derivatives, and their acute toxicity and cytotoxicity.

The antimycobacterial activity of nine biphenyl methanone (BPM) derivatives against standard strains of Mycobacterium kansasii, M. avium and M. malmoense was determined by colorimetric assay in microplates with the dye Alamar Blue. Acute toxicity of these compounds was also analyzed by determination of CO2 concentration in a respirometric assay using Escherichia coli. The compounds showed weak antimycobacterial activity with a minimal inhibitory concentration (MIC) over 0.038 mmol l-1 and no toxicity was found in E. coli up to 400 mmol l-1. No cytotoxicity was observed on V79 cells up to 0.35 mmol l-1 with 7 of the BPM derivatives, with two exceptions (X = SO2CH3, NO2) that showed some toxicity. The greatest antimycobacterial activity was observed with the SO2CH3 derivative and the application of Principal Component Analysis (PCA) showed a relationship between structure and antimycobacterial activity of the compounds. Two descriptors, nucleophilic superdelocalizability of carbon atom and pi-hydrophobic constant, were necessary to describe this relationship.

Bothrops lanceolatus (Fer de lance) venom induces oedema formation and increases vascular permeability in the mouse hind paw.

The ability of snake venoms to increase vascular permeability and to induce oedema through the release of pharmacologically active substances is well known. We have studied the oedema and vascular permeability induced by Bothrops lanceolatus venom in male Swiss white mice. Paw oedema was induced by the subplantar injection of B. lanceolatus venom (125-1000 ng/paw) and was quantified as the increase in paw weight. Changes in vascular permeability were assessed by measuring the amount of Evans blue dye extravasation. The oedema and the increase in vascular permeability were maximal within 2 h and had resolved after 24 h. The administration of the vasodilator iloprost (20 ng/paw) immediately after B. lanceolatus venom potentiated the oedema and the increase in vascular permeability by approximately four-fold. Pretreating the mice with indomethacin, dexamethasone, NDGA or BW A4C inhibited the venom-induced oedema and the increase in vascular permeability. In contrast, histamine, serotonin and PAF-acether antagonists (mepyramine, cyproheptadine and WEB 2086, respectively) were ineffective. Histological examination showed that B. lanceolatus venom (250 ng and 500 ng/paw) caused thickening of the inner dermal layers which was accompanied by extensive intercellular spaces indicative of oedema. In addition, there was a marked infiltration of inflammatory cells, particularly neutrophils, into the underlying muscle layer. The latter, however, remained morphologically unaffected during the 3 h of observation. Venom doses larger than 500 ng/paw produced intense haemorrhage. These results indicate that B. lanceolatus venom induces oedema and increases vascular permeability in the mouse hind paw. The principal mediators of this inflammatory response are cyclooxygenase and lipoxygenase products.

Structure-activity relationship analysis of 4'-bromo-[1,1'-biphenyl]-4-yl 4-X-phenyl methanone derivatives and activity against Mycobacterium tuberculosis.

Principal Component Analysis (PCA) and Artificial Neural Network (ANN) were used to analyze the relationship between the structure and the activities of a series of nine biphenyl-phenyl methanone derivatives against Mycobacterium tuberculosis in vitro. Both PCA and ANN were able to classify these derivatives in two categories: low active and highly active compounds. Empirical and theoretical descriptors were used in the classification process. The descriptors selected by PCA indicated that the reactivity plays an important role in the determination of antimycobacterial activity of biphenylphenyl methanone derivatives (BPM). The BPM showed a moderate activity against the M. tuberculosis strain tested with the exception of chloride-, bromide- and nitroderivatives (when X = Cl, Br, NO2) which were the most actives against M. tuberculosis in vitro among all the methanones studied.

Inter-relaçäo entre doença periodontal e comportamento endodôntico / The interrelationship between periodontal disease and endodontic involvement

Foi feita a revisäo da literatura sobre a inter-relaçäo entre a doença periodontal (periodontite) e a polpa dental, evidenciando principalmente a existência da correlaçäo entre a patologia pulpar e doença periodontal, via canais acessórios, especialmente quando a polpa encontra-se necrosada. Embora alteraçäo pulpar avançada só ocorra quando a destruiçäo periodontal atinge a regiäo do ápice radicular, uma avaliaçäo mais detalhada das condiçöes periodontais e pulpares é sugerida

[Endomyocardial fibrosis: surgical treatment]. / Endomiocardiofibrose: tratamento cirúrgico.

The authors analyse the experience acquired for surgical treatment of endomyocardiofibrosis. Among the 15 patients submitted to the operation, nine had the biventricular form, four had the disease in the right ventricle and two only in the left ventricle. The surgery consisted of endocardioectomy of the ventricles (RV--04,LV--02, bilateral--08) and replacement of the diseased atrioventricular valves (mitral--02, tricuspid--06, mitral and tricuspid--07). In one patient there was severe obstruction of the anterior descending artery and a bypass was done. Three patients had associated rheumatic mitral stenosis. There was one early operative death and three late deaths (respectively 13.34 and 37 months later). Two patients required re-operation. The first one, 33 months later, to replace the mitral valve which had been preserved in the first procedure, and the second, 12 months later, who presented ventricular septal defect secondary to rupture of the weak septum. Of all the patients who underwent surgery, 11 survived and all, except one, have had a good course. The detailed analysis of this series permitted us to conclude that: 1st--the general use of the bidimensional echocardiography in high risk patients, allows early diagnosis in a greater number of them; 2nd, the surgery must be early to avoid cardiac and extracardiac injury due to the disease; 3rd--a low profile valve must be used; 4th--to this moment there have been no signs of recurrence; 5th--surgical treatment appears to improve the course of this terrible disease.