Toxicity and physicochemical parameters of composts including distinct residues from agribusiness and slaughterhouse sludge.

Composting is useful for treatment of residues from agribusiness, but the potential toxicity of the final compost should be evaluated before its agricultural destination. The objective of this study was to evaluate the physicochemical characteristics and the toxicity of agribusiness residues using onion seeds as bioindicators. All tested treatments were composed by sludge from a swine slaughterhouse and sawdust. Besides the control, which included no additional materials, the other treatments included aviary bedding, rice husk and residue from tobacco industries as structuring materials. After 120 days of composting, for all treatments, the temperature inside the composting piles approached the environmental temperature, the physicochemical parameters indicated that the composts were stabilized and, except for the treatment including tobacco residues, that could be used for agriculture without impairing plant germination. Although the treatments including tobacco residues and rice husk showed evidence of cytotoxicity and genotoxicity at the beginning of the composting period, that was not observed for the treatment including aviary bedding. Such potential toxicity was not observed at the end of composting for any of the tested treatments.

Physicochemical and Microbiological Quality of Dietetic Functional Mixed Cerrado Fruit Jam during Storage.

The objective of the research was to evaluate changes of dietetic functional mixed cerrado fruit jam (marolo, sweet passion fruit, and soursop) processed in a vacuum pot and stored for 180 days in BODs at 25°C and 35°C. The parameters evaluated were pH, soluble solids (SS), titratable acidity (TA), total sugars (TS), total carotenoids (TC), total phenolics (TP), vitamin C, antioxidant activity (DPPH), and microbiological analysis. There was a significant effect of storage time on pH, SS, TA, TC, TS, and TP. Vitamin C and DPPH showed an effect for the temperature x storage time interaction. Statistical models are not adjusted for pH and SS, presenting an average of 4.15 and 61%, respectively. Carotenoids decreased up to105 days; total sugars increased up to 105 days. The TP, vitamin C, and DPPH, at the temperatures evaluated, showed a decrease up to 105 days. Yeasts and filamentous fungi were not detected.

Application of mesocellular siliceous foams (MCF) for surface-assisted laser desorption ionization mass spectrometry (SALDI-MS) Analysis of fingermarks.

Recent advances in nanotechnology applied in forensic sciences have contributed to consider new approaches including chemical evaluation of latent fingermarks. Significant improvement to the detection of small organic molecules has been reached with matrix-free methods associated to laser desorption/ionization mass spectrometry. The present study investigated the application of mesocellular siliceous foam (MCF) as an ionizing agent for laser desorption/ionization (LDI-MS) analysis of fingermarks as a proof of concept research. Fingermarks from three different donors were deposited directly onto a MALDI target plate and α-CHCA matrix solution, MCF ethanolic suspension or MCF/magnetic powder mixture were used for treatment. Microscopy characterization of MCF support showed particles with irregular morphology and variable sizes, and a unordered porous surface with pores diameter ranging from about 10 to 20 nm. Results showed less intense peaks in the spectra produced by the MCF support (control). Analysis of fingermarks showed ions related to endogenous and exogenous molecular components, including possible lipids from human sebum and quaternary ammonium cations commonly present in cosmetics. Promising and reproducible results were obtained for the fingermarks dusted with the MCF/magnetic powder mixture. Considering the forensic applications of nanomaterials for the analysis of small molecules in biological samples by matrix-free LDI techniques, the advantages of silica based materials should be further investigated.

Estabilidade da caranha em diferentes períodos de armazenamento / Stabilityof the caranhain differentstorage periods

O objetivo deste estudo foi verificar a influência do tempo de armazenamento na qualidade microbiológica, físico-química e sensorial do pescado caranha (Piaractusmesopotamicus). Os pescados foram estocados em gelo durante zero, sete, 14, 21 e 28 dias e submetidos às contagens de micro-organismos mesófilos, psicrotróficos, coliformes a 35ºC e 45ºC, Salmonella sp. e estafilococos coagulase positiva. Foram realizadas análises de temperatura, pH, acidez, bases voláteis, proteínas, lipídeos, cinzas, umidade, prova de cocção, bem como análise sensorial. As contagens de mesófilos, psicrotróficos, coliformes a 35ºC e 45ºC aumentaram com o tempo de armazenamento. A presença de Salmonella sp. não foi constatada, enquanto a contagem de estafilococos coagulase positiva foi de <10 (est) UFC/g em todos os períodos de estocagem. Observou-se, ainda, que o tempo de armazenamento apresentou influência em todas as variáveis físico-químicas, exceto para temperatura. Na análise sensorial, foi constatado um aumento linear do índice de qualidade (IQ) ao longo do armazenamento, e a rejeição ocorreu aos 14 dias.(AU)

The objective of this study was to verify the influence of storage time on the microbiological, physical-chemical, and sensorial quality of the fish (Piaractusmesopotamicus). The fish were stored on ice for 0, 7, 14, 21, and 28 days and submitted to counts of mesophilic, psychrotrophic, coliform microorganisms at 35ºC and 45ºC, Salmonella sp. and coagulase positive staphylococci. Analyzes of temperature, pH, acidity, volatile bases, proteins, lipids, ashes, humidity, cooking test, as well as sensorial analysis were performed. Counts of mesophiles, psychrotrophic, coliforms at 35°C and 45°C increased with storage time. The presence of Salmonella sp. was not observed, whereas the coagulase positive Staphylococcus count was <10 (est) CFU/g in all storage periods. It was also observed that the storage time had influence on all physical-chemical variables, except for temperature. In the sensorial analysis, a linear increase of the quality index (IQ) was verified throughout the storage and the rejection occurred at 14 days.(AU)

Utilização de técnicas de manejo comportamental e neuropsicológicas para intervenção dos transtornos de aprendizagem / Behavioral management and neuropsychological techniques for learning disabilies intervention

O diagnóstico de dislexia do desenvolvimento é um fator de risco para as dificuldades de aprendizagem da matemática e exige programas de intervenção específicos e alicerçados no perfil cognitivo desse grupo clínico. Além dos déficits cognitivos, esses indivíduos também apresentam prejuízos emocionais e sociais. O objetivo do estudo foi avaliar a eficácia de um programa de intervenção da matemática, focado na habilidade de transcodificação numérica. Técnicas de manejo comportamental foram associadas ao treino cognitivo para lidar com os prejuízos emocionais. A intervenção foi realizada em três pacientes com diagnóstico de dislexia e sintomas de baixa autoeficácia, desmotivação e ansiedade de desempenho. Os pacientes participaram de sessões individuais, sendo que o programa foi estruturado em 12 sessões de 60 minutos cada. Para avaliação da eficácia do programa utilizou-se um delineamento de pré e pós-teste. Os resultados demonstraram que todos os pacientes obtiveram ganhos tanto quantitativos, quanto qualitativos. Entretanto, nem todas as habilidades treinadas obtiveram uma melhora significativa, atribui-se esse desfecho a diferenças no perfil cognitivo e emocional dos pacientes...

The diagnosis of developmental dyslexia is a risk factor to mathematical learning difficulties and requires specific intervention programs grounded in the cognitive profile of this clinical group. Besides the cognitive deficits, these individuals have emotional and social impairment. The aim of the study was to evaluate the effectiveness of a math intervention program focused on numerical transcoding ability. Behavioral management techniques were used to deal with the emotional disregulation, during the cognitive intervention. The intervention was performed with three patients diagnosed with dyslexia and symptoms of low self-efficacy, demotivation and performance anxiety. Patients participated in individual sessions of the program which was structured in 12 sessions of 60 minutes each. In order to evaluate the effectiveness of the program, it was used pretest and posttest design. The results demonstrated that all patients had both quantitative and qualitative gain. However, some abilities did not show significative improvement. This scenario is related to pacients differences in cognitive and emotional profile

Valor nutritivo do resíduo da indústria processadora de abacaxi (Ananas comosus L.) em dietas para ovinos. 1. Consumo, digestibilidade aparente e balanços energético e nitrogenado / Nutritive value of pineapple by-product (Ananas comosus L.) in diets for sheep. 1. Intake, apparent digestibility, energetic and nitrogenous balance

O presente estudo foi conduzido para avaliar a influência da inclusão do resíduo do processamento de abacaxi (Ananas comosus L.) nas dietas sobre os consumos (por unidade de tamanho metabólico - UTM) e coeficientes de digestibilidade da matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), extrato etéreo (EE), fibra detergente neutro (FDN), fibra detergente ácido (FDA), hemiceluloses (HCEL), celulose (CEL) e energia de dietas experimentais isofibrosas e isoprotéicas. Avaliaram-se também os balanços nitrogenados e de energia dos animais. Vinte ovinos machos, inteiros receberam rações com quatro níveis de inclusão do resíduo (0; 11 por cento; 16 por cento; 27 por cento) em base de matéria seca, em delineamento inteiramente ao acaso, com cinco repetições por tratamento. Maiores consumos de matéria seca foram evidenciados quando as rações continham 11 por cento do resíduo. Maiores consumos de proteína bruta, fibra detergente neutro, fibra detergente ácido e celulose (g/UTM) e energia metabolizável (kcal/UTM) foram apresentados por animais alimentados com dietas contendo 11 por cento de resíduo em relação ao das dietas com 27 por cento de inclusão (P<0,05). Maior coeficiente de digestibilidade da FDA ocorreu para dietas que não continham o resíduo de abacaxi. Os coeficientes de digestibilidade da CEL foram semelhantes. Os balanços energéticos e protéicos foram positivos. Melhores resultados para os parâmetros analisados foram observados para dietas que incluíam até 16 por cento do resíduo de abacaxi na base da matéria seca.

The influence of increasing levels of pineapple by-product (Ananas comosus L.) on intake (unit metabolic size - UMS) and apparent digestibility ( percent) of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicelluloses (HCEL) and cellulose (CEL) and energy of isofibrous and isoproteic experimental diets of sheep were evaluated. Energetic and nitrogenous balance were also measured. Twenty rams were randomly allotted to four treatments in a completely randomized design with five replications. The treatments were formulated to contain zero; 11, 16 and 27 percent of pineapple by-product on DM basis. Higher dry matter intake was observed on 11 percent pineapple by-product diet. CP, NDF, ADF, CEL intake (g/UMS) and metabolizable energy intake (kcal/UMS) of 11 percent pineapple by-product diet were higher than 27 percent pineapple by-product diet (P<0.05). ADF digestibility was higher for 0 percent pineapple by-product diet. Energy and nitrogenous balances were positives. Diets formulated to contain up to 16 percent of pineapple by-product presented the best results.

Early use of terlipressin in catecholamine-resistant shock improves cerebral perfusion pressure in severe traumatic brain injury.

BACKGROUND: Maintaining adequate cerebral perfusion pressure is an essential aspect in the treatment of severe acute brain injury. To accomplish this therapeutic goal vasopressors are usually required. Vasopressin is an important endogenous stress hormone and the infusion of low-dose vasopressin and terlipressin has been used to reverse severe hypotension. CASE REPORT: A 14-year-old male patient was admitted to the emergency room after a motorcycle accident. The patient had suffered severe traumatic brain injury, the Glasgow coma score (GCS) was four and there were signs of aspiration of gastric contents. Systemic inflammatory response syndrome and shock refractory to fluid management, norepinephrine and steroid replacement ensued. A terlipressin infusion, as a bolus dose of 1 mg, is associated with the ability to improve cerebral perfusion pressure with concomitant reduction of 80% of norepinephrine doses. DISCUSSION: The present report illustrates the potential benefits of terlipressin in refractory shock in a patient with severe traumatic brain injury. An increase in cerebral perfusion pressure (CPP) and a huge decrease in the dose of norepinephrine were observed. In the setting of severe brain injury associated with refractory hypotension, terlipressin may improve mean arterial pressure and cerebral perfusion pressure. CONCLUSION: In the setting of severe brain injury associated with refractory hypotension, terlipressin may have a role as a rescue therapy.

The anti-IRBP IgG1 and IgG2a response does not correlate with susceptibility to experimental autoimmune uveitis.

Susceptibility to experimental autoimmune uveitis (EAU) in inbred mice has been associated with a dominant Th1 response. Elevated anti-inter-photoreceptor retinoid-binding protein (anti-IRBP) IgG2a/IgG1 antibody ratios have been implicated as candidate markers to predict disease severity. In the present study, both the anti-IRBP antibody isotype and severity of EAU phenotypes were examined in 4 non-isogenic genetically selected mouse lines to determine if they can be used as general markers of disease. Mice between 8 and 12 weeks old selected for high (H(III)) or low (L(III)) antibody response and for maximum (AIR(MAX)) or minimum (AIR(MIN)) acute inflammatory reaction (AIR) were immunized with IRBP. Each experiment was performed with at least 5 mice per group. EAU was evaluated by histopathology 21 days after immunization and the minimal criterion was inflammatory cell infiltration of the ciliary body, choroid and retina. Serum IgG1- and IgG2a-specific antibodies were determined by ELISA. EAU was graded by histological examination of the enucleated eyes. The incidence of EAU was lower in AIR(MIN) mice whereas in the other strains approximately 40% of the animals developed the disease. Low responder animals did not produce anti-IRBP IgG2a antibodies or interferon-gamma. No correlation was observed between susceptibility to EAU and anti-IRBP isotype profiles. Susceptibility to EAU is related to the intrinsic capacity to mount higher inflammatory reactions and increased production of anti-IRBP IgG2a isotype is not necessarily a marker of this immunologic profile.

The anti-IRBP IgG1 and IgG2a response does not correlate with susceptibility to experimental autoimmune uveitis

Susceptibility to experimental autoimmune uveitis (EAU) in inbred mice has been associated with a dominant Th1 response. Elevated anti-inter-photoreceptor retinoid-binding protein (anti-IRBP) IgG2a/IgG1 antibody ratios have been implicated as candidate markers to predict disease severity. In the present study, both the anti-IRBP antibody isotype and severity of EAU phenotypes were examined in 4 non-isogenic genetically selected mouse lines to determine if they can be used as general markers of disease. Mice between 8 and 12 weeks old selected for high (H III) or low (L III) antibody response and for maximum (AIR MAX) or minimum (AIR MIN) acute inflammatory reaction (AIR) were immunized with IRBP. Each experiment was performed with at least 5 mice per group. EAU was evaluated by histopathology 21 days after immunization and the minimal criterion was inflammatory cell infiltration of the ciliary body, choroid and retina. Serum IgG1- and IgG2a-specific antibodies were determined by ELISA. EAU was graded by histological examination of the enucleated eyes. The incidence of EAU was lower in AIR MIN mice whereas in the other strains approximately 40 percent of the animals developed the disease. Low responder animals did not produce anti-IRBP IgG2a antibodies or interferon-gamma. No correlation was observed between susceptibility to EAU and anti-IRBP isotype profiles. Susceptibility to EAU is related to the intrinsic capacity to mount higher inflammatory reactions and increased production of anti-IRBP IgG2a isotype is not necessarily a marker of this immunologic profile.

Caracterização demográfica da raça Mangalarga Marchador / Demographic characterization of Mangalarga Marchador breed

Data from the Brazilian Mangalarga Marchador Breed Association, including information on 292,012 animals borned from 1949 to 2000 were used to describe population structure. Frequency tables, central tendency and variation measurements according to owner, breeder, type of registration (known and unknown pedigree), year and month of births, progeny number for stallions and mares were presented. A total of 72.6 percent of the animals originated from the Southeast States of Brazil. The maximum number of birth (6.7 percent) was observed in 1990 and approximately 90.0 percent of the births occurred from September to March. Concerning progeny numbers, 73.6 percent of the 90,018 mares produced an average of 3.8 and a maximum of 22 offsprings. For the stallions these numbers were 26.2 and 1,322, respectively. The average generation interval was 8.9 years.

Fas-FasL interaction modulates nitric oxide production in Trypanosoma cruzi-infected mice.

During acute Trypanosoma cruzi infection in mice, many leucocytes undergo apoptosis. Although apoptosis has been ascribed to increased levels of nitric oxide (NO) and Fas-FasL interaction, the importance of this phenomenon in modulating the host response against T. cruzi is unknown. Herein, the role of NO- and Fas-FasL-induced apoptosis in modulating the immune response to T. cruzi was evaluated using mice deficient in Fas expression (MRL/MpJ-Fas lpr) and inducible nitric oxide synthase (iNOS) knockout mice (iNOS-/-). The results showed that besides decreasing apoptosis induction after infection, impairment of the Fas-FasL interaction resulted in decreased NO production, as a consequence of enhanced T helper 2 (Th2) cytokine production. Differently, blockage of NO-induced apoptosis resulted in uncontrolled cytokine production, rather than a biased Th2 cytokine pattern. Together, these results suggested that Fas and FasL-induced apoptosis could be implied in modulation of the immune response against T. cruzi by interfering with cytokine and NO production during the acute phase of the infection.

Detection of DNA in the plasma of septic patients.

Small amounts of plasma-free DNA have been observed both in healthy individuals and in patients with various diseases such as systemic lupus erythematosus, rheumatoid arthritis, viral hepatitis, and cancer. This communication demonstrates that septic patients also release DNA in plasma. After DNA extraction from plasma, exon 1 of the K-ras gene was amplified by PCR and products were analyzed by dot-blot hybridization. Plasmas from polytraumatic patients and control healthy individuals were used for comparisons with septic patients. Our results show that septic patients present DNA in their plasma. As far as we know, this is the first evidence of circulating DNA in septic patients.

Free DNA induces modification on the protein synthesis profile of human peripheral blood mononuclear cells of healthy donors.

Understanding how free DNA might act as a signal between cells is important for knowing how DNA orchestrates immune responses and for optimizing the therapeutic of cancer, infection and immunologic diseases. This communication demonstrates that DNAs from different origins (bacteria, T. cruzi, HeLa cells) and synthetic oligonucleotide containing an unmethylated CpG motif are capable of inducing alterations in the protein profile of normal human leukocytes. As far as we know there have been no similar studies regarding the comparative effects of different free DNAs on early protein synthesis of human peripheral blood mononuclear cells.

Trypanosoma cruzi-infected cardiomyocytes produce chemokines and cytokines that trigger potent nitric oxide-dependent trypanocidal activity.

BACKGROUND: The pathogenesis of myocarditis that occurs in Trypanosoma cruzi-infected mice is still poorly understood. Therefore, it is important to know the mediators that trigger leukocyte migration to the heart as well as the cellular source of these possible mediators. In this study, we investigated (1) NO synthase (NOS) induction, (2) NO synthesis, (3) trypanocidal activity, and (4) chemokine and cytokine mRNA expression by isolated cardiomyocytes infected with T cruzi. METHODS AND RESULTS: Mouse cardiomyocytes were isolated, infected with T cruzi, and evaluated for induction of inducible NOS (iNOS), nitrite production, trypanocidal activity, and cytokine and chemokine mRNA expression. We found that T cruzi-infected murine embryonic cardiomyocytes produced nitrite and expressed mRNAs for the chemokines chemokine growth-related oncogene, monokine induced by interferon-gamma, macrophage inflammatory protein-2, interferon-gamma-inducible protein, RANTES, and monocyte chemotactic protein, for iNOS, and for the cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta. Separate addition of IL-1beta, interferon-gamma, TNF-alpha or monocyte chemotactic protein, macrophage inflammatory protein-2, and interferon-gamma-inducible protein, to cultured cardiomyocytes resulted in NO production but low trypanocidal activity. However, simultaneous addition of IL-1beta, interferon-gamma, and TNF-alpha or the chemokines to cultures resulted in the induction of iNOS, high levels of nitrite, and a marked trypanocidal activity. The iNOS/L-arginine pathway mediated the latter activity, inasmuch as it was inhibited by treatment with N:(G)-monomethyl-L-arginine. CONCLUSIONS: These results indicate that iNOS activation and the proinflammatory cytokines and chemokines produced by cardiomyocytes are likely to control parasite growth and cell influx, thus contributing to the pathogenesis of chagasic cardiomyopathy seen in T cruzi-infected mice.

The adjuvant effect of jacalin on the mouse humoral immune response to trinitrophenyl and Trypanosoma cruzi.

We have evaluated the adjuvant action of jacalin, a lectin obtained from seeds of Artocarpus integrifolia, on humoral immune response against the trinitrophenyl (TNP) hapten when conjugated to it and to Trypanosoma cruzi. The protective effect of parasite-specific antibodies generated in mice immunized with epimastigote forms of T. cruzi plus jacalin was also evaluated by determining the parasitemia levels of animals after infection with 1000 trypomastigote forms. Immunization of mice with trinitrophenylated jacalin (TNP-JAC) in saline resulted in an antibody response to the TNP hapten that was eight and 16 times higher than that found in mice immunized with TNP-human gamma globulin (TNP-HGG) or TNP-bovine serum albumin (TNP-BSA), respectively. In addition, immunization with either a lysate or viable epimastigote forms of T. cruzi in the presence of jacalin resulted in a marked increase in the levels of anti-T. cruzi antibodies. The protective action of antibodies against acute infection by T. cruzi was evident when mice were immunized with 1.0 x 10(5) epimastigotes plus jacalin. These animals had a significantly lower parasitemia than those immunized with epimastigotes alone. In contrast, mice immunized with 1.0 x 10(6) epimastigotes developed very low levels of parasitemia, regardless of the presence of jacalin. These data suggest that jacalin is a potent adjuvant in the humoral response to TNP and T. cruzi, and that the protective action of the T. cruzi-specific antibodies depends on the number of parasites used in the immunization protocol.

Gamma interferon modulates CD95 (Fas) and CD95 ligand (Fas-L) expression and nitric oxide-induced apoptosis during the acute phase of Trypanosoma cruzi infection: a possible role in immune response control.

We have previously shown that splenocytes from mice acutely infected with Trypanosoma cruzi exhibit high levels of nitric oxide (NO)-mediated apoptosis. In the present study, we used the gamma interferon (IFN-gamma)-knockout (IFN-gamma(-/-)) mice to investigate the role of IFN-gamma in modulating apoptosis induction and host protection during T. cruzi infection in mice. IFN-gamma(-/-) mice were highly susceptible to infection and exhibited significant reduction of NO production and apoptosis levels in splenocytes but normal lymphoproliferative response compared to the infected wild-type (WT) mice. Furthermore, IFN-gamma modulates an enhancement of Fas and Fas-L expression after infection, since the infected IFN-gamma(-/-) mice showed significantly lower levels of Fas and Fas-L expression. The addition of recombinant murine IFN-gamma to spleen cells cultures from infected IFN-gamma(-/-) mice increased apoptosis levels, Fas expression, and NO production. In the presence of IFN-gamma and absence of NO, although Fas expression was maintained, apoptosis levels were significantly reduced but still higher than those found in splenocytes from uninfected mice, suggesting that Fas-Fas-L interaction could also play a role in apoptosis induction in T. cruzi-infected mice. Moreover, in vivo, the treatment of infected WT mice with the inducible nitric oxide synthase inhibitor aminoguanidine also led to decreased NO and apoptosis levels but not Fas expression, suggesting that IFN-gamma modulates apoptosis induction by two independent and distinct mechanisms: induction of NO production and of Fas and Fas-L expression. We suggest that besides being of crucial importance in mediating resistance to experimental T. cruzi infection, IFN-gamma could participate in the immune response control through apoptosis modulation.

Expression of heat shock protein 70 in leukocytes of patients with sepsis.

The heat shock proteins are known to protect cells against diverse injuries such as cytotoxicity by TNFalpha acting mainly as chaperones for denatured proteins. Lipopolysaccharide stimulates the production and the release of numerous endogenous mediators of sepsis: tumor necrosis factor alpha, interleukin-1, and interleukin-6 that induce fever production. Moreover, temperature at 40 degrees C is sufficient to induce heat shock and attenuate both TNFalpha and IL-1 expression. We demonstrate a distinct profile in gene expression of HSP 70 family in leukocytes obtained from different phases of septic patients. Our findings strongly suggest that HSP 70 may play a role in the outcome of septic shock patients.

Nitric oxide-induced apoptotic cell death in the acute phase of Trypanosoma cruzi infection in mice.

Production of gamma-interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) in Trypanosoma cruzi-infected mice results in the activation of inducible nitric oxide synthase (iNOS) and in elevated nitric oxide (NO) synthesis, which is important for the macrophage trypanocidal activity. However, NO has been shown to be involved in suppression of host immunity. In the present investigation, we studied the role of NO in inducing apoptosis in cells from BALB/c mice acutely infected by T. cruzi. Splenocytes from infected mice had a reduced cell viability and elevated levels of spontaneous apoptosis after 48 h in culture. Inhibition of NO production by the addition of the L-arginine analog NG-monomethyl-L-arginine (L-NMMA), or of monoclonal antibodies (mAbs) to IFN-gamma or TNF-alpha spleen cells, partially restored cell viability and caused a decrease in the levels of apoptosis in splenocytes from infected animals. Spleen cells from T. cruzi-infected mice had an apoptosis-specific pattern of internucleosomal DNA fragmentation which was most marked at the ninth day after infection when the plasma NO levels and parasitemia were increased. Treatment of infected mice with L-NMMA, anti-TNF-alpha, or anti-IFN-gamma mAbs caused reduction of both NO production and the amount of apoptotic cells, suggesting that NO plays a direct role in the induction of apoptosis in vivo. Taken together, these data support the hypothesis that, as well as modulating immunosuppression, NO produced by IFN-gamma and TNF-alpha activated macrophages plays a role in apoptosis induction during the acute phase of experimental T. cruzi infection.