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Research paper thumbnail of Investigations on surrogate fuels for high-octane oxygenated gasolines

Research paper thumbnail of Germinal center architecture disturbance during Plasmodium berghei ANKA infection in CBA mice

Malaria Journal, 2007

Background Immune responses to malaria blood stage infection are in general defective, with the n... more Background Immune responses to malaria blood stage infection are in general defective, with the need for long-term exposure to the parasite to achieve immunity, and with the development of immunopathology states such as cerebral malaria in many cases. One of the potential reasons for the difficulty in developing protective immunity is the poor development of memory responses. In this paper, the potential association of cellular reactivity in lymphoid organs (spleen, lymph nodes and Peyer's patches) with immunity and pathology was evaluated during Plasmodium berghei ANKA infection in CBA mice. Methods CBA mice were infected with 1 × 106P. berghei ANKA-parasitized erythrocytes and killed on days 3, 6–8 and 10 of infection. The spleen, lymph nodes and Peyer's patches were collected, fixed in Carson's formalin, cut in 5 μm sections, mounted in glass slides, stained with Lennert's Giemsa and haematoxylin-eosin and analysed with bright-field microscopy. Results Early (day 3) strong activation of T cells in secondary lymphoid organs was observed and, on days 6–8 of infection, there was overwhelming activation of B cells, with loss of conventional germinal center architecture, intense centroblast activation, proliferation and apoptosis but little differentiation to centrocytes. In the spleen, the marginal zone disappeared and the limits between the disorganized germinal center and the red pulp were blurred. Intense plasmacytogenesis was observed in the T cell zone. Conclusion The observed alterations, especially the germinal center architecture disturbance (GCAD) with poor centrocyte differentiation, suggest that B cell responses during P. berghei ANKA infection in mice are defective, with potential impact on B cell memory responses.

Research paper thumbnail of Brazilian Plasmodium falciparum isolates: investigation of candidate polymorphisms for artemisinin resistance before introduction of artemisinin-based combination therapy

Research paper thumbnail of Exogenous nitric oxide decreases brain vascular inflammation, leakage and venular resistance during Plasmodium berghei ANKA infection in mice

Journal of Neuroinflammation, 2011

Background Cerebral malaria (CM) is a lethal complication of Plasmodium falciparum infections. In... more Background Cerebral malaria (CM) is a lethal complication of Plasmodium falciparum infections. In the Plasmodium berghei ANKA (PbA) murine model, CM is associated with marked brain inflammation, increased expression of endothelial cell adhesion molecules and leukocyte and platelet accumulation in brain vessels, causing vascular occlusion and decreased blood flow, damaging the endothelium and leading to blood-brain barrier breakdown, leakage and hemorrhages. Exogenous nitric oxide (NO) administration largely prevents the syndrome. Here we evaluated whether the mechanism of action of NO in preventing murine CM is related to its anti-inflammatory properties and to protection of the endothelium. Methods C57Bl/6 mice infected with PbA were treated twice a day with saline or dipropylenetriamineNONOate (DPTA-NO). Endothelial cell adhesion molecule (ICAM-1, VCAM, E- and P-selectin) expression in brain tissue on day 6 of infection was assessed in both groups by western blot. For intravital microscopy studies, DPTA-NO-treated and saline-treated mice with a previously implanted closed cranial window were injected with albumin-FITC, anti-CD45-TxR and anti-CD41-FITC antibodies on day 6 of infection for quantification of albumin leakage, leukocyte and platelet adherence in pial vessels. Results PbA-infected mice treated with the NO-donor DPTA-NO showed decreased expression of ICAM-1 and P-selectin, but not VCAM-1, in the brain, compared to saline-treated mice. DPTA-NO treatment also decreased the number of adherent leukocytes and platelets in pial vessels, particularly in venules 30-50 μm in diameter, decreased inflammatory vascular resistance and prevented the occurrence of arteriolar and venular albumin leakage observed in saline-treated PbA-infected mice, as assessed by intravital microscopy. Conclusions These results indicate that the protective effect of exogenous NO on murine CM is associated with decreased brain vascular expression of inflammatory markers resulting in attenuated endothelial junction damage and facilitating blood flow.

Research paper thumbnail of Plasmodium berghei ANKA infection induces thymocyte apoptosis and thymocyte depletion in CBA mice

Memorias Do Instituto Oswaldo Cruz, 2006

Research paper thumbnail of Mining Cellular Automata DataBases throug PCA Models

Computing Research Repository, 2005

Research paper thumbnail of Aotus infulatus monkey is susceptible to Plasmodium falciparum infection and may constitute an alternative experimental model for malaria

Memorias Do Instituto Oswaldo Cruz, 2000

Research paper thumbnail of Algorithms to predict cerebral malaria in murine models using the SHIRPA protocol

Malaria Journal, 2010

Background Plasmodium berghei ANKA infection in C57Bl/6 mice induces cerebral malaria (CM), which... more Background Plasmodium berghei ANKA infection in C57Bl/6 mice induces cerebral malaria (CM), which reproduces, to a large extent, the pathological features of human CM. However, experimental CM incidence is variable (50-100%) and the period of incidence may present a range as wide as 6-12 days post-infection. The poor predictability of which and when infected mice will develop CM can make it difficult to determine the causal relationship of early pathological changes and outcome. With the purpose of contributing to solving these problems, algorithms for CM prediction were built. Methods Seventy-eight P. berghei-infected mice were daily evaluated using the primary SHIRPA protocol. Mice were classified as CM+ or CM- according to development of neurological signs on days 6-12 post-infection. Logistic regression was used to build predictive models for CM based on the results of SHIRPA tests and parasitaemia. Results The overall CM incidence was 54% occurring on days 6-10. Some algorithms had a very good performance in predicting CM, with the area under the receiver operator characteristic (auROC) curve ≥ 80% and positive predictive values (PV+) ≥ 95, and correctly predicted time of death due to CM between 24 and 72 hours before development of the neurological syndrome (auROC = 77-93%; PV+ = 100% using high cut off values). Inclusion of parasitaemia data slightly improved algorithm performance. Conclusion These algorithms work with data from a simple, inexpensive, reproducible and fast protocol. Most importantly, they can predict CM development very early, estimate time of death, and might be a valuable tool for research using CM murine models.

Research paper thumbnail of Interferência de caruru-de-mancha, Maria-pretinha, picão-preto e tiririca em tomateiro industrial

Bragantia, 2010

The objective of the present research was to study the effect of interference of slender amaranth... more The objective of the present research was to study the effect of interference of slender amaranth (Amaranthus viridis), American black nightshade (Bidens pilosa), purple nutsedge (Cyperus rotundus) and hairy beggarticks (Solanum americanum) on height, leaf area, chlorophyll content, dry mass and macronutrients accumulation and fruits fresh mass of processing tomato. The treatments were: (a) two tomato plants + two ones of A. viridis; (b) two tomato plants + two ones of B. pilosa; (c) two tomato plants + two ones of C. rotundus; e (d) two tomato plants + two ones of S. americanum. Moreover, a weed-free check with two tomato plants was maintained. For each weed species, the effect on tomato was the same for all evaluated characteristics, independently to distance used. A. viridis and S. americanum showed higher competitive potential than B. pilosa and C. rotundus. Chlorophyll content, plant height and leaf area of tomato was not affected by weed coexistence. B. pilosa and C. rotundus did not influenced on tomato macronutrients accumulation while A. viridis and S. americanum affected differentially it in function of distance used, and A. viridis was the most competitive species. Fresh mass of tomato fruits was not reduced due to coexistence with the four weed species.

Research paper thumbnail of Investigations on surrogate fuels for high-octane oxygenated gasolines

Research paper thumbnail of Germinal center architecture disturbance during Plasmodium berghei ANKA infection in CBA mice

Malaria Journal, 2007

Background Immune responses to malaria blood stage infection are in general defective, with the n... more Background Immune responses to malaria blood stage infection are in general defective, with the need for long-term exposure to the parasite to achieve immunity, and with the development of immunopathology states such as cerebral malaria in many cases. One of the potential reasons for the difficulty in developing protective immunity is the poor development of memory responses. In this paper, the potential association of cellular reactivity in lymphoid organs (spleen, lymph nodes and Peyer's patches) with immunity and pathology was evaluated during Plasmodium berghei ANKA infection in CBA mice. Methods CBA mice were infected with 1 × 106P. berghei ANKA-parasitized erythrocytes and killed on days 3, 6–8 and 10 of infection. The spleen, lymph nodes and Peyer's patches were collected, fixed in Carson's formalin, cut in 5 μm sections, mounted in glass slides, stained with Lennert's Giemsa and haematoxylin-eosin and analysed with bright-field microscopy. Results Early (day 3) strong activation of T cells in secondary lymphoid organs was observed and, on days 6–8 of infection, there was overwhelming activation of B cells, with loss of conventional germinal center architecture, intense centroblast activation, proliferation and apoptosis but little differentiation to centrocytes. In the spleen, the marginal zone disappeared and the limits between the disorganized germinal center and the red pulp were blurred. Intense plasmacytogenesis was observed in the T cell zone. Conclusion The observed alterations, especially the germinal center architecture disturbance (GCAD) with poor centrocyte differentiation, suggest that B cell responses during P. berghei ANKA infection in mice are defective, with potential impact on B cell memory responses.

Research paper thumbnail of Brazilian Plasmodium falciparum isolates: investigation of candidate polymorphisms for artemisinin resistance before introduction of artemisinin-based combination therapy

Research paper thumbnail of Exogenous nitric oxide decreases brain vascular inflammation, leakage and venular resistance during Plasmodium berghei ANKA infection in mice

Journal of Neuroinflammation, 2011

Background Cerebral malaria (CM) is a lethal complication of Plasmodium falciparum infections. In... more Background Cerebral malaria (CM) is a lethal complication of Plasmodium falciparum infections. In the Plasmodium berghei ANKA (PbA) murine model, CM is associated with marked brain inflammation, increased expression of endothelial cell adhesion molecules and leukocyte and platelet accumulation in brain vessels, causing vascular occlusion and decreased blood flow, damaging the endothelium and leading to blood-brain barrier breakdown, leakage and hemorrhages. Exogenous nitric oxide (NO) administration largely prevents the syndrome. Here we evaluated whether the mechanism of action of NO in preventing murine CM is related to its anti-inflammatory properties and to protection of the endothelium. Methods C57Bl/6 mice infected with PbA were treated twice a day with saline or dipropylenetriamineNONOate (DPTA-NO). Endothelial cell adhesion molecule (ICAM-1, VCAM, E- and P-selectin) expression in brain tissue on day 6 of infection was assessed in both groups by western blot. For intravital microscopy studies, DPTA-NO-treated and saline-treated mice with a previously implanted closed cranial window were injected with albumin-FITC, anti-CD45-TxR and anti-CD41-FITC antibodies on day 6 of infection for quantification of albumin leakage, leukocyte and platelet adherence in pial vessels. Results PbA-infected mice treated with the NO-donor DPTA-NO showed decreased expression of ICAM-1 and P-selectin, but not VCAM-1, in the brain, compared to saline-treated mice. DPTA-NO treatment also decreased the number of adherent leukocytes and platelets in pial vessels, particularly in venules 30-50 μm in diameter, decreased inflammatory vascular resistance and prevented the occurrence of arteriolar and venular albumin leakage observed in saline-treated PbA-infected mice, as assessed by intravital microscopy. Conclusions These results indicate that the protective effect of exogenous NO on murine CM is associated with decreased brain vascular expression of inflammatory markers resulting in attenuated endothelial junction damage and facilitating blood flow.

Research paper thumbnail of Plasmodium berghei ANKA infection induces thymocyte apoptosis and thymocyte depletion in CBA mice

Memorias Do Instituto Oswaldo Cruz, 2006

Research paper thumbnail of Mining Cellular Automata DataBases throug PCA Models

Computing Research Repository, 2005

Research paper thumbnail of Aotus infulatus monkey is susceptible to Plasmodium falciparum infection and may constitute an alternative experimental model for malaria

Memorias Do Instituto Oswaldo Cruz, 2000

Research paper thumbnail of Algorithms to predict cerebral malaria in murine models using the SHIRPA protocol

Malaria Journal, 2010

Background Plasmodium berghei ANKA infection in C57Bl/6 mice induces cerebral malaria (CM), which... more Background Plasmodium berghei ANKA infection in C57Bl/6 mice induces cerebral malaria (CM), which reproduces, to a large extent, the pathological features of human CM. However, experimental CM incidence is variable (50-100%) and the period of incidence may present a range as wide as 6-12 days post-infection. The poor predictability of which and when infected mice will develop CM can make it difficult to determine the causal relationship of early pathological changes and outcome. With the purpose of contributing to solving these problems, algorithms for CM prediction were built. Methods Seventy-eight P. berghei-infected mice were daily evaluated using the primary SHIRPA protocol. Mice were classified as CM+ or CM- according to development of neurological signs on days 6-12 post-infection. Logistic regression was used to build predictive models for CM based on the results of SHIRPA tests and parasitaemia. Results The overall CM incidence was 54% occurring on days 6-10. Some algorithms had a very good performance in predicting CM, with the area under the receiver operator characteristic (auROC) curve ≥ 80% and positive predictive values (PV+) ≥ 95, and correctly predicted time of death due to CM between 24 and 72 hours before development of the neurological syndrome (auROC = 77-93%; PV+ = 100% using high cut off values). Inclusion of parasitaemia data slightly improved algorithm performance. Conclusion These algorithms work with data from a simple, inexpensive, reproducible and fast protocol. Most importantly, they can predict CM development very early, estimate time of death, and might be a valuable tool for research using CM murine models.

Research paper thumbnail of Interferência de caruru-de-mancha, Maria-pretinha, picão-preto e tiririca em tomateiro industrial

Bragantia, 2010

The objective of the present research was to study the effect of interference of slender amaranth... more The objective of the present research was to study the effect of interference of slender amaranth (Amaranthus viridis), American black nightshade (Bidens pilosa), purple nutsedge (Cyperus rotundus) and hairy beggarticks (Solanum americanum) on height, leaf area, chlorophyll content, dry mass and macronutrients accumulation and fruits fresh mass of processing tomato. The treatments were: (a) two tomato plants + two ones of A. viridis; (b) two tomato plants + two ones of B. pilosa; (c) two tomato plants + two ones of C. rotundus; e (d) two tomato plants + two ones of S. americanum. Moreover, a weed-free check with two tomato plants was maintained. For each weed species, the effect on tomato was the same for all evaluated characteristics, independently to distance used. A. viridis and S. americanum showed higher competitive potential than B. pilosa and C. rotundus. Chlorophyll content, plant height and leaf area of tomato was not affected by weed coexistence. B. pilosa and C. rotundus did not influenced on tomato macronutrients accumulation while A. viridis and S. americanum affected differentially it in function of distance used, and A. viridis was the most competitive species. Fresh mass of tomato fruits was not reduced due to coexistence with the four weed species.