COVID-19 impedimetric biosensor based on polypyrrole nanotubes, nickel hydroxide and VHH antibody fragment: specific, sensitive, and rapid viral detection in saliva samples.

SARS-CoV-2 rapid spread required urgent, accurate, and prompt diagnosis to control the virus dissemination and pandemic management. Several sensors were developed using different biorecognition elements to obtain high specificity and sensitivity. However, the task to achieve these parameters in combination with fast detection, simplicity, and portability to identify the biorecognition element even in low concentration remains a challenge. Therefore, we developed an electrochemical biosensor based on polypyrrole nanotubes coupled via Ni(OH)2 ligation to an engineered antigen-binding fragment of heavy chain-only antibodies (VHH) termed Sb#15. Herein we report Sb#15-His6 expression, purification, and characterization of its interaction with the receptor-binding domain (RBD) of SARS-CoV-2 in addition to the construction and validation of a biosensor. The recombinant Sb#15 is correctly folded and interacts with the RBD with a dissociation constant (KD) of 27.1 ± 6.4 nmol/L. The biosensing platform was developed using polypyrrole nanotubes and Ni(OH)2, which can properly orientate the immobilization of Sb#15-His6 at the electrode surface through His-tag interaction for the sensitive SARS-CoV-2 antigen detection. The quantification limit was determined as 0.01 pg/mL using recombinant RBD, which was expressively lower than commercial monoclonal antibodies. In pre-characterized saliva, both Omicron and Delta SARS-CoV-2 were accurately detected only in positive samples, meeting all the requirements recommended by the World Health Organization for in vitro diagnostics. A low sample volume of saliva is needed to perform the detection, providing results within 15 min without further sample preparations. In summary, a new perspective allying recombinant VHHs with biosensor development and real sample detection was explored, addressing the need for accurate, rapid, and sensitive biosensors.

As diversas faces da morte de crianças na perspectiva de médicos e enfermeiros / The diverse faces of child death from the perspective of doctors and nurses

Introdução: Adoecimento e morte de crianças são eventos pouco aceitos na sociedade. Objetivo: Analisar a percepção de médicos e enfermeiros de terapia intensiva sobre a morte de crianças. Métodos: Estudo de aborda-gem qualitativa, com médicos e enfermeiros de três Unidades de Terapia Intensiva (UTI Pediátrica, UTI Neonatal e UTI Cardiológica) de um hospital de ensino. Foram realizadas entrevistas semiestruturadas gravadas, transcritas e analisadas segundo análise de conteúdo na modalidade temática. Resultados: Foram entrevistados 14 profis-sionais, com idade entre 28-53 anos, que possuíam tempo mínimo de dois anos de atuação em terapia intensiva e média de 43 horas semanais de trabalho. Os sentimentos e atitudes diante da morte emergiram da análise das falas e foram categorizados nos seguintes temas: percepção da morte na infância, obstinação terapêutica e so-frimento no encontro com as famílias. Os profissionais reconheceram lacunas na formação durante a graduação e pós-graduação para lidar com a morte de crianças. Sofrimento, ansiedade, culpa, frustração e impotência foram relatados, demonstrando a complexidade que envolve situações de morte de criança. A condição clínica e a capaci-dade de interação da criança influenciaram nas atitudes e na própria maneira do profissional lidar com a morte. A espiritualidade foi um importante mecanismo de enfrentamento. Conclusão: A morte de crianças em UTI provoca sentimentos ambivalentes em médicos e enfermeiros responsáveis pelo seu cuidado. Os profissionais sofrem pela morte de alguém que ainda não desfrutou da vida, porém a aceitam quando pensam no fim de uma vida marcada por sofrimentos e limitações impostos pela doença. O contato com o tema morte durante a formação profissional e nas discussões regulares dos serviços podem auxiliar na forma de lidar com esse evento. A espiritualidade foi um importante recurso de enfrentamento. (AU)

ntroduction: Sickness and death of children are little accepted events in society. Objective: To analyze the perception of intensive care doctors and nurses about the death of children. Methods: Qualitative approach study, with doctors and nurses from three Intensive Care Units (Pediatric ICU, Neonatal ICU and Cardiological ICU) of a teaching hospital. Recorded semi-structured interviews were carried out, transcribed and analyzed according to content analysis in the thematic modality. Results: 14 professionals were interviewed, aged 28-53 years, with a minimum of 2 years of intensive care experience time and an average of 43 hours of work per week. The feelings and attitudes towards death emerged from the speech analysis and were categorized in the following themes: per-ception of death in childhood, therapeutic obstinacy and suffering in meeting with families. Professionals recognized gaps in training during undergraduate and graduate studies to deal with the death of children. Suffering, anxiety, guilt, frustration, impotence and guilt were reported, demonstrating the complexity of child death situations. The clinical condition and the child's ability to interact influenced the attitudes and the professional's way of dealing with death. Spirituality was an important mechanism of confrontation. Conclusion: The death of children in ICU causes ambivalent feelings in doctors and nurses responsible for their care. Professionals suffer for the death of someone who has not yet enjoyed life, but accept it when they think about the end of a life marked by suffering and limitations imposed by the disease. Contact with the subject of death during professional training and in the regular discussions of services can help in the way to deal with this event. Spirituality was an important resource of coping. (AU)

Selection of common bean genotypes for the Cerrado/Pantanal ecotone via mixed models and multivariate analysis.

The common bean, Phaseolus vulgaris, is predominantly grown on small farms and lacks accurate genotype recommendations for specific micro-regions in Brazil. This contributes to a low national average yield. The aim of this study was to use the methods of the harmonic mean of the relative performance of genetic values (HMRPGV) and the centroid, for selecting common bean genotypes with high yield, adaptability, and stability for the Cerrado/Pantanal ecotone region in Brazil. We evaluated 11 common bean genotypes in three trials carried out in the dry season in Aquidauana in 2013, 2014, and 2015. A likelihood ratio test detected a significant interaction between genotype x year, contributing 54% to the total phenotypic variation in grain yield. The three genotypes selected by the joint analysis of genotypic values in all years (Carioca Precoce, BRS Notável, and CNFC 15875) were the same as those recommended by the HMRPGV method. Using the centroid method, genotypes BRS Notável and CNFC 15875 were considered ideal genotypes based on their high stability to unfavorable environments and high responsiveness to environmental improvement. We identified a high association between the methods of adaptability and stability used in this study. However, the use of centroid method provided a more accurate and precise recommendation of the behavior of the evaluated genotypes.

An effective approach for modifying carbonaceous materials with niobium single sites to improve their catalytic properties.

In this paper we show a very simple route for the incorporation of catalytically active niobium species on the surface of carbon materials, such as graphene oxide, carbon nanotubes and activated carbon. Some existing methods of incorporating a transition metal on a support have involved co-precipitation or wet impregnation, to obtain the corresponding oxides. These methods, however, cause reduction in the specific area of the support and can also form large metal oxide particles with loss of metal exposure. Therefore, here we present a novel way to add catalytically active species on the surfaces of different types of carbon through the formation of interaction complexes between the metal precursor and the functional groups of the carbon matrix. Because of the excellent catalytic properties exhibited by the niobium species we choose the NH4[NbO(C2O4)2(H2O)2]·2H2O salt as the model precursor. The characterization by XPS reveals the presence of the niobium species indicated by the displacement of the peaks between 206-212 eV related to the oxalate species according to the spectrum from pure niobium oxalate. Images obtained by TEM and SEM show the typical morphologies of carbonaceous materials without the niobium oxide formation signal, which indicates the presence of niobium complexes as isolated sites on the carbon surfaces. This new class of materials exhibited excellent properties as catalysts for pollutant oxidation. The presence of Nb promotes the catalytic activation of H2O2 generating hydroxyl radicals in situ, which allows their use in the organic compound oxidation processes. Tests for DBT oxidation indicate that Nb significantly improves the removal of such pollutants in biphasic reactions with removal around 90% under the tested conditions. Theoretical calculations showed that the most favorable adsorption model is an ionic complex presenting a ΔG = -108.7 kcal mol(-1) for the whole adsorption process.

Hydrocarbon concentration and source appraisal in atmospheric particulate matter (PM2.5) of an urban tropical area.

Polycyclic aromatic (46 PAHs) and aliphatic hydrocarbons (C12-C40) were studied in atmospheric particulate matter sampled in Rio de Janeiro Metropolitan Area (RJMA). In total, 236 samples from six different sites were collected simultaneously and weekly over 1 year (January-December 2011) allowing a robust atmospheric characterization of fine particulate matter (PM2.5). Hydrocarbon concentration was in general low compared to previous studies in the area (PAHs range 0.25-19.3 ng m(-3)), possibly due to changes in fuel composition over time. Precipitation is the main meteorological parameter that rules particulate and hydrocarbon concentration, modifying PAH typology by scavenging. Aliphatic and aromatic diagnostic ratios gave indications conflicting with combustion features. However, ratios showed differences among sites. Principal component analysis (PCA) associated to multiple linear regressions (MLR) allowed quantitative estimate of sources and effectively indicated vehicular emission as the main hydrocarbon source in the atmospheric particulate matter.

Physalis angulata: A New Natural Host of Tomato chlorosis virus in Brazil.

Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV) are the two Solanaceae-infecting Crinivirus species (family Closteroviridae) of worldwide importance. In Brazil, only ToCV has been detected under natural conditions infecting tomato (Solanum lycopersicum), sweet pepper (Capsicum annuum), and potato (S. tuberosum), causing foliar chlorosis (1, 3). However, there are no formal reports of alternative weed hosts of ToCV. During crop surveys in Capão Bonito, São Paulo State, Brazil (May 2011), a high incidence (above 20%) of plants of the weed, cut leaf ground cherry (Physalis angulata L.) growing around and within a tomato (cv. Alambra) field with a high incidence of ToCV, were found displaying interveinal chlorosis on the lower leaves, similar to those induced by magnesium deficiency. The P. angulata plants also had high populations of whiteflies (Bemisia tabaci biotype B). Ten leaf samples were taken from individual symptomatic ground cherry and tomato plants for Crinivirus testing. Total nucleic acids were extracted from 2 g of symptomatic and healthy leaf tissues of both hosts using Whatman CF-11 cellulose (Sigma) as described (4). The purified double stranded RNA samples were used as a template in reverse transcription (RT)-PCR using specific primers targeting the p22 gene region in the genome of ToCV (2). Only the 566-bp ToCV-specific amplicon was detected in all field samples. Sequences of samples from the P. angulata and tomato cDNA amplicons were identical to each other (GenBank Accession No. JX187514) and they showed 99% identity with the ToCV RNA 1 from a tomato isolate from Florida (AY903447). This confirmed the initial hypothesis of Crinivirus infection. Cuttings of symptomatic P. angulata plants were also obtained and kept in a voile cage under greenhouse conditions together with healthy seedlings of P. angulata and the begomovirus-resistant inbred tomato line 'TX-468RG.' Fifty aviruliferous B. tabaci (biotype B) adults were placed in the cage. Similar symptoms were observed 50 days after exposure to whiteflies in both hosts. Transmission to P. angulata and to 'TX-468RG' was also confirmed via sequencing of ToCV-specific amplicon, demonstrating the infectivity of the isolate to both hosts. To our knowledge, this is the first report of P. angulata as a natural host of ToCV in Brazil. This weed is often present in the commercial fields because of its natural tolerance to herbicides currently used in tomato production. The ToCV-infected P. angulata plants might serve as alternative sources of inoculum for the surrounding tomato fields. The environmental persistence of P. angulata combined with its intense whitefly colonization might allow a year-round ToCV exposure for tomato plants under field conditions in this major production area of Brazil where at least 25 million tomato plants are cultivated annually. References: (1) J. C. Barbosa et al. Trop. Plant Pathol. 36: 256, 2011. (2) M. I. Font et al. Plant Dis. 86:696, 2002. (3) D. M. S. Freitas et al. Plant Dis. 96:593, 2012. (4) R. A. Valverde et al. Plant Dis. 74:285, 1990.

Anatomy and lignification status of the Lophanthera lactescens Ducke plant grown in vitro.

This aim of this study was to evaluate the lignification in young stems of the Lophanthera lactescens Ducke plant grown in vitro L. lactescens (Malpighiaceae), a species endemic in the Brazilian Amazon that possesses both medicinal properties and could be used in the forest product industry. Plants grown in vitro condition in MS medium were analyzed using Infrared (IR) microspectroscopy in a diffuse reflectance mode, fluorescence microscopy. Moreover, histochemical tests such as the Wiesner and Maüle test were run to monitor the process of lignification in cell walls. The spectra of IR microscopy recorded using cross section tissue are representative of guaiacyl/syringyl lignin, based on the 1336 and 1246 cm-1 signal. Individuals presenting stem sprains, resulting from the marked development, produced gelatinous fibers with a clear cellulose layer. Initially, fluorescence microscopy demonstrated lignin deposition in the cell corner region having progressive deposition in the secondary wall of tracheary elements of the stem.

Serum total and bone alkaline phosphatase and tartrate-resistant acid phosphatase activities for the assessment of bone fracture healing in dogs / Fosfatase alcalina total, isoenzima óssea da fosfatase alcalina e fosfatase ácida resistente ao tartarato na monitorização da cicatrização de fraturas ósseas

O objetivo deste trabalho foi estudar o padrão de variação da atividade sérica da fosfatase alcalina total (tALP), da isoenzima óssea da fosfatase alcalina (BALP) e da fosfatase ácida resistente ao tartarato (TRAP), assim como a variação da concentração dos minerais séricos durante o processo de cicatrização de fraturas ósseas no cão. A variação sérica destes marcadores do metabolismo ósseo foi avaliada em nove cães com fraturas diafisárias fechadas de ossos longos, submetidas a tratamento cirúrgico para osteosíntese. Durante o período pós-operatório, sete animais evoluíram no sentido de uma normal união óssea, sendo que dois deles desenvolveram um processo de não união óssea. Foram observados, relativamente à BALP, valores de actividade sérica mais elevados e com diferença estatística (P<0,05) no grupo de animais que evoluiu no sentido de uma normal união óssea, comparativamente ao grupo de animais que evoluiu no sentido do processo de não união. No grupo de animais que evoluiu para a completa união óssea foram, adicionalmente, observados valores diminuidos (P<0,05) da atividade sérica da TRAP, até ao dia 60 do período pós-operatório seguido de uma elevação estatisticamente significativa após este período. Em conclusão, os biomarcadores do metabolismo ósseo poderão vir a constituir um método auxiliar de diagnóstico na monitorização do processo de cicatrização de fracturas ósseas, possibilitando, a detecção precoce de complicações pós-operatórias.

Serum total and bone alkaline phosphatase and tartrate-resistant acid phosphatase activities for the assessment of bone fracture healing in dogs / Fosfatase alcalina total, isoenzima óssea da fosfatase alcalina e fosfatase ácida resistente ao tartarato na monitorização da cicatrização de fraturas ósseas

O objetivo deste trabalho foi estudar o padrão de variação da atividade sérica da fosfatase alcalina total (tALP), da isoenzima óssea da fosfatase alcalina (BALP) e da fosfatase ácida resistente ao tartarato (TRAP), assim como a variação da concentração dos minerais séricos durante o processo de cicatrização de fraturas ósseas no cão. A variação sérica destes marcadores do metabolismo ósseo foi avaliada em nove cães com fraturas diafisárias fechadas de ossos longos, submetidas a tratamento cirúrgico para osteosíntese. Durante o período pós-operatório, sete animais evoluíram no sentido de uma normal união óssea, sendo que dois deles desenvolveram um processo de não união óssea. Foram observados, relativamente à BALP, valores de actividade sérica mais elevados e com diferença estatística (P<0,05) no grupo de animais que evoluiu no sentido de uma normal união óssea, comparativamente ao grupo de animais que evoluiu no sentido do processo de não união. No grupo de animais que evoluiu para a completa união óssea foram, adicionalmente, observados valores diminuidos (P<0,05) da atividade sérica da TRAP, até ao dia 60 do período pós-operatório seguido de uma elevação estatisticamente significativa após este período. Em conclusão, os biomarcadores do metabolismo ósseo poderão vir a constituir um método auxiliar de diagnóstico na monitorização do processo de cicatrização de fracturas ósseas, possibilitando, a detecção precoce de complicações pós-operatórias.(AU)

Leishmanicidal effect of LLD-3 (1), a nor-triterpene isolated from Lophanthera lactescens.

Leishmanicidal activity of 6alpha, 7alpha, 15beta, 16beta, 24-pentacetoxy-22alpha-carbometoxy-21beta,22beta-epoxy-18beta-hydroxy-27,30-bisnor-3,4-secofriedela-1,20 (29)-dien-3,4 R-olide (LLD-3 (1)) isolated from Lophanthera lactescens Ducke, a member of the Malpighiaceae, was demonstrated against intramacrophage amastigote forms (IC(50) of 0.41mug/mL). The in vitro leishmanicidal effect of Glucantime, the first choice drug for leishmaniasis treatment, was increased by LLD-3 (1) association. The leishmanicidal effect of LLD-3 (1) was not due to stimulation of nitric oxide production by macrophages. LLD-3 (1) was also not cytotoxic for mouse peritoneal macrophages or B cells as assessed by the XTT and Trypan blue exclusion assays. LLD-3 (1) was unable to affect proliferation of naïve or activated B and T cells, as well as the B cells immunoglobulin synthesis. Cellularity of different tissues, liver and kidney functions were not altered in mice treated with LLD-3 (1), as well as the histology pattern of different organs. Our results add LLD-3 (1) as a potential drug candidate for treatment of leishmaniasis.

Efeito clínico do uso do parecoxib em modelo de sinovite induzida em pôneis / Clinical effect of parecoxib in induced synovitis in horses

Um modelo experimental de sinovite em pôneis foi usado para avaliar o efeito do parecoxib, um antiinflamatório não-esteroidal (AINE) seletivo injetável. Cinco dias após indução da sinovite, três pôneis foram tratados com 0,55mg/kg/dia (IV) de parecoxib e três receberam solução salina 0,9 por cento (IV) por cinco dias. A avaliação de parâmetros clínicos dos animais e físico-químicos do líquido sinovial foi realizada antes da indução de sinovite, antes e 12, 24, 48, 72, 96 e 120 horas após o início do tratamento. A injeção intra-articular com adjuvante completo de Freund induziu sinovite de intensidade moderada a grave. Os pôneis tratados com parecoxib apresentaram diminuição do grau de claudicação; manutenção da flexão articular, do comprimento do passo, da temperatura retal e da freqüência cardíaca; e atenuação do grau de efusão articular. Embora o parecoxib, na dose utilizada, não tenha apresentado efeito sobre os parâmetros do líquido sinovial das articulações com sinovite, sua ação antipirética, antiinflamatória e principalmente analgésica foi observada.

An experimental synovitis model was used in ponies to evaluate the effect of parecoxib, a selective non steroidal anti-inflammatory drug (NSAID). Five days after synovitis induction, three ponies received parecoxib (IV) 0.55mg/kg/day and three ponies received sterile 0.9 percent saline solution (IV) for five days. Clinical parameters and synovial fluid were evaluated before synovitis induction, prior treatment and 12, 24, 48, 96, and 120 hours after the first treatment. The intra-articular injection of Freund's complete adjuvant induced a moderate to severe synovitis. The parecoxib treated ponies showed lameness reduction; maintenance of stride length, articular flexion, temperature, and heart rate; and attenuation of articular effusion. Although the used dosage of parecoxib had no effect on evaluated synovial fluid parameters, antipyretic, anti-inflammatory, and especially analgesic effects were observed.

Efeito clínico do uso do parecoxib em modelo de sinovite induzida em pôneis / Clinical effect of parecoxib in induced synovitis in horses

Um modelo experimental de sinovite em pôneis foi usado para avaliar o efeito do parecoxib, um antiinflamatório não-esteroidal (AINE) seletivo injetável. Cinco dias após indução da sinovite, três pôneis foram tratados com 0,55mg/kg/dia (IV) de parecoxib e três receberam solução salina 0,9 por cento (IV) por cinco dias. A avaliação de parâmetros clínicos dos animais e físico-químicos do líquido sinovial foi realizada antes da indução de sinovite, antes e 12, 24, 48, 72, 96 e 120 horas após o início do tratamento. A injeção intra-articular com adjuvante completo de Freund induziu sinovite de intensidade moderada a grave. Os pôneis tratados com parecoxib apresentaram diminuição do grau de claudicação; manutenção da flexão articular, do comprimento do passo, da temperatura retal e da freqüência cardíaca; e atenuação do grau de efusão articular. Embora o parecoxib, na dose utilizada, não tenha apresentado efeito sobre os parâmetros do líquido sinovial das articulações com sinovite, sua ação antipirética, antiinflamatória e principalmente analgésica foi observada.(AU)

An experimental synovitis model was used in ponies to evaluate the effect of parecoxib, a selective non steroidal anti-inflammatory drug (NSAID). Five days after synovitis induction, three ponies received parecoxib (IV) 0.55mg/kg/day and three ponies received sterile 0.9 percent saline solution (IV) for five days. Clinical parameters and synovial fluid were evaluated before synovitis induction, prior treatment and 12, 24, 48, 96, and 120 hours after the first treatment. The intra-articular injection of Freund's complete adjuvant induced a moderate to severe synovitis. The parecoxib treated ponies showed lameness reduction; maintenance of stride length, articular flexion, temperature, and heart rate; and attenuation of articular effusion. Although the used dosage of parecoxib had no effect on evaluated synovial fluid parameters, antipyretic, anti-inflammatory, and especially analgesic effects were observed.(AU)

A food-grade delivery system for Lactococcus lactis and evaluation of inducible gene expression.

The genetic improvement of Lactococcus lactis is a matter of biotechnological interest in the food industry and in the pharmaceutical and medical fields. However, to construct a food-grade delivery system, both the presence of antibiotic markers or plasmid sequences should be avoided and the maintenance and expression of the cloned gene should be guaranteed. The objective of this work was to produce crossover mutants of L. lactis with a reporter gene under the control of an inducible promoter in order to evaluate the level of gene expression. We utilized a nuclease gene of Staphylococcus aureus as a reporter gene, P(nisA) as the nisin-inducible promoter, a non-essential gene involved in histidine biosynthesis of L. lactis as the site for homologous recombination, and pRV300 as a suicide vector for the genomic integration in L. lactis NZ9000. Single- and double-crossover mutants were identified by genotype and phenotype. Relative to episomal transformants of L. lactis, the level of expression of the heterologous protein after nisin induction was similar in the crossover mutants, suggesting that a single copy of the heterologous gene can be used to produce the protein of interest.

[First epileptic crisis. Analysis of risk factors for recurrence]. / Crise epiléptica única. Análise dos fatores de risco para recorrência.

We studied children who presented with a first seizure and came to the outpatient clinic for childhood from September/1989 to July/1996. The following risk factors were assessed: age, sex, type and etiology of the seizure, sleep state at time of seizure, family history of seizures, electroencephalogram (EEG) and computerized tomography (CT). Our purpose was to assess the risk factors in univariable and multivariable analysis. We found two groups of patients according to the etiology: (a) idiopathic cases (IC) and (b) symptomatic cases (SC). This last group had only two patients and was excluded from the analysis. We studied only the IC group with 86 patients. Seizure recurrence was observed 29 children (33%), during 2.4 years. Only patients with abnormal EEG and family history for unprovoked seizures had a higher risk of recurrence (p < 0.003). After the first unprovoked seizure estimate of recurrence by survival curves was 18% at first semester, 27% at first year, 35% at second year and 38% at third year.

Quimioprofilaxia da doença de Chagas: bloqueio da transmissão transfusional por produtos naturais / Chemyprophylaxis of Chagas disease: blockage of blood transfusion transmission by natural products

Em busca da solução para o serio problema da transmissão transfusional da doença de Chagas em nosso meio, realizamos a avaliação de produtos naturais corn atividade tripanosomicida. Os testes "in vitro" foram realizados incubando-se a 4°C, sangue de camundongos contendo ± 10(6)/ ml formas tripomastigotas de Trypanosoma cruzi corn os extratos vegetais. Após diferentes períodos de incubação, frações sangüíneas foram examinadas em microscopia de fase. Os extratos que apresentaram atividade tripanosomicida ate 48 horas de incubação, foram examinados em microscopia eletrônica corn intuito de verificarmos sua toxicidade contra os elementos normais do sangue. Foram testados 242 extratos obtidos de 81 vegetais a 56 demonstraram atividade.

Considering the serius problem of blood transfusion transmission of Chagas disease in our environment, we realized the evalution of natural products against Chagas diseases. The tests were realized "in vitro" by in incubation at 4ºC mouse blood having ± 10(6)/ml of Trypanosoma cruzi, sample "y" and "Colombina" with the plant extracts. After different times of incubation, blood fractions were examined by phase microscopy. The drugs that showed activity until 48 hours of incubation, were examined by electron microscopy to virify the toxicity to blood elements. The tests were realized with 242 extracts from 81 plants and 56 extracts showed activity against T. cruzi.