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Search Results: 1 - 10 of 13104 matches for " Marcelo Einicker-Lamas "
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Inositol metabolism in Trypanosoma cruzi: potential target for chemotherapy against Chagas' disease
OLIVEIRA, MECIA M.;EINICKER-LAMAS, MARCELO;
Anais da Academia Brasileira de Ciências , 2000, DOI: 10.1590/S0001-37652000000300015
Abstract: chagas' disease is a debilitating and often fatal disease caused by the protozoan parasite trypanosoma cruzi. the great majority of surface molecules in trypanosomes are either inositol-containing phospholipids or glycoproteins that are anchored into the plasma membrane by glycosylphosphatidylinositol anchors. the polyalcohol myo-inositol is the precursor for the biosynthesis of these molecules. in this brief review, recent findings on some aspects of the molecular and cellular fate of inositol in t. cruzi life cycle are discussed and identified some points that could be targets for the development of parasite-specific therapeutic agents.
Inositol metabolism in Trypanosoma cruzi: potential target for chemotherapy against Chagas' disease
OLIVEIRA MECIA M.,EINICKER-LAMAS MARCELO
Anais da Academia Brasileira de Ciências , 2000,
Abstract: Chagas' disease is a debilitating and often fatal disease caused by the protozoan parasite Trypanosoma cruzi. The great majority of surface molecules in trypanosomes are either inositol-containing phospholipids or glycoproteins that are anchored into the plasma membrane by glycosylphosphatidylinositol anchors. The polyalcohol myo-inositol is the precursor for the biosynthesis of these molecules. In this brief review, recent findings on some aspects of the molecular and cellular fate of inositol in T. cruzi life cycle are discussed and identified some points that could be targets for the development of parasite-specific therapeutic agents.
In Vitro Effects of Natrum muriaticum in Kidney Cell Lines MDCK and LLC-PK1
Rafael Harduim,Ven???-cio Veiga,Vanessa Baldez,Marcelo Einicker-Lamas
International Journal of High Dilution Research , 2011,
Abstract: Previous papers have indicated that homeopathic solutions modify the cellular and biochemical aspects of cells maintained in culture. In this study, the effects of Natrum muriaticum, a medicine used in the homeopathic clinic for the treatment of hypertension, were evaluated in kidney MDCK and LLC-PK1 cell lines. The following cellular parameters were analyzed: viability, morphology and expression of the (Na+-K+)-ATPase and the angiotensin II receptors AT1 and AT2. The cell lines were plated (5.0 x 104 cells/mL) in DMEM supplemented with 10% fetal calf serum (FCS). After 24 hours at 37 °C, DMEM was re-fed with the addition of 10% (V/V) and 1% (V/V) of the following samples: Natrum muriaticum 30CH, water 30CH and non-dynamized sterile distilled water to do the MTT assay. The results obtained from these groups were compared to those obtained by incubation of the cells in culture medium free of these solutions (Control). Cell viability was assessed by a colorimetric MTT ELISA assay (490nm). The values from four independent experiments performed in quintuplicate were plotted and statistically analyzed by Sigma Plot v.11 (Jandel Scientific). The morphology of MDCK cells was evaluated by optical microscope after Giemsa ¢a a ¢s staining. The expression of the (Na++K+)-ATPase and AT1/AT2 of LLC-PK1 cells was evaluated by Western Blot (WB) analysis. For this experimental set, 5.0x104 cells/mL were incubated in DMEM supplemented with 10% FCS and daily culture medium was replaced by a new one, containing: Natrum muriaticum 30CH and water 30CH. Additionally, cells were treated for 5, 10 and 15 days with 1% of specific solutions and the total protein was measured by the Lowry method, after cell lysis. The samples were analyzed by electrophoresis in SDS-PAGE (12% gel) and transferred to nitrocellulose membrane. This membrane was incubated with specific primary antibodies (anti-(Na++K+)-ATPase, anti-AT1 and AT2 or anti-anti-beta-actin). The detection was performed using ECL system and Hyperfilm. MTT assays showed a statistically significant reduction in cellular mitochondrial activity (p<0.001) probably attributed to an osmotic effect due to the use of 10% (V/V) concentration rather than 1% (V/V). The optical microscopy analysis revealed no significant morphological changes in MDCK and LLC-PK1 cells submitted to the different treatments when compared to controls groups. The WB analysis indicated a proportional increase in (Na++K+)-ATPase content according to an increase in the homeopathic stimuli. Although preliminary, these results show for the first time, that the
Platelet Activating Factor Blocks Interkinetic Nuclear Migration in Retinal Progenitors through an Arrest of the Cell Cycle at the S/G2 Transition
Lucianne Fragel-Madeira,Tamara Meletti,Rafael M. Mariante,Robson Q. Monteiro,Marcelo Einicker-Lamas,Robson R. Bernardo,Angela H. Lopes,Rafael Linden
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0016058
Abstract: Nuclear migration is regulated by the LIS1 protein, which is the regulatory subunit of platelet activating factor (PAF) acetyl-hydrolase, an enzyme complex that inactivates the lipid mediator PAF. Among other functions, PAF modulates cell proliferation, but its effects upon mechanisms of the cell cycle are unknown. Here we show that PAF inhibited interkinetic nuclear migration (IKNM) in retinal proliferating progenitors. The lipid did not, however, affect the velocity of nuclear migration in cells that escaped IKNM blockade. The effect depended on the PAF receptor, Erk and p38 pathways and Chk1. PAF induced no cell death, nor a reduction in nucleotide incorporation, which rules out an intra-S checkpoint. Notwithstanding, the expected increase in cyclin B1 content during G2-phase was prevented in the proliferating cells. We conclude that PAF blocks interkinetic nuclear migration in retinal progenitor cells through an unusual arrest of the cell cycle at the transition from S to G2 phases. These data suggest the operation, in the developing retina, of a checkpoint that monitors the transition from S to G2 phases of the cell cycle.
Metabolic Programming during Lactation Stimulates Renal Na+ Transport in the Adult Offspring Due to an Early Impact on Local Angiotensin II Pathways
Ricardo Luzardo,Paulo A. Silva,Marcelo Einicker-Lamas,Susana Ortiz-Costa,Maria da Gra?a Tavares do Carmo,Leucio D. Vieira-Filho,Ana D. O. Paix?o,Lucienne S. Lara,Adalberto Vieyra
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0021232
Abstract: Several studies have correlated perinatal malnutrition with diseases in adulthood, giving support to the programming hypothesis. In this study, the effects of maternal undernutrition during lactation on renal Na+-transporters and on the local angiotensin II (Ang II) signaling cascade in rats were investigated.
Undernutrition Affects Cell Survival, Oxidative Stress, Ca2+ Handling and Signaling Pathways in Vas Deferens, Crippling Reproductive Capacity
Humberto Muzi-Filho, Camila G. P. Bezerra, Alessandro M. Souza, Leonardo C. Boldrini, Christina M. Takiya, Felipe L. Oliveira, Renata T. Nesi, Samuel S. Valen?a, Marcelo Einicker-Lamas, Adalberto Vieyra, Lucienne S. Lara, Valeria M. N. Cunha
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069682
Abstract: Background The aim of this work was to investigate the mechanisms by which chronic malnutrition (CM) affects vas deferens function, leading to compromised reproductive capacity. Previous studies have shown that maternal malnutrition affects the reproductive tracts of adult male offspring. However, little is known about the effects of CM, a widespread life-long condition that persists from conception throughout growth to adult life. Methodology/Principal Findings Young adult male rats, which were chronically malnourished from weaning, presented decreased total and haploid cells in the vas deferens, hypertrophy of the muscle layer in the epididymal portion of the vas deferens and intense atrophy of the muscular coat in its prostatic portion. At a molecular level, the vas deferens tissue of CM rats exhibited a huge rise in lipid peroxidation and protein carbonylation, evidence of an accentuated increase in local reactive oxygen species levels. The kinetics of plasma membrane Ca2+-ATPase activity and its kinase-mediated phosphorylation by PKA and PKC in the vas deferens revealed malnutrition-induced modifications in velocity, Ca2+ affinity and regulation of Ca2+ handling proteins. The severely crippled content of the 12-kDa FK506 binding protein, which controls passive Ca2+ release from the sarco(endo) plasmic reticulum, revealed another target of malnutrition related to intracellular Ca2+ handling, with a potential effect on forward propulsion of sperm cells. As a possible compensatory response, malnutrition led to enhanced sarco(endo) plasmic reticulum Ca2+-ATPase activity, possibly caused by stimulatory PKA-mediated phosphorylation. Conclusions/Significance The functional correlates of these cellular and molecular hallmarks of chronic malnutrition on the vas deferens were an accentuated reduction in fertility and fecundity.
Mechanisms Involving Ang II and MAPK/ERK1/2 Signaling Pathways Underlie Cardiac and Renal Alterations during Chronic Undernutrition
Paulo A. Silva, Gustavo Monnerat-Cahli, Amaury Pereira-Acácio, Ricardo Luzardo, Luzia S. Sampaio, Marcia A. Luna-Leite, Lucienne S. Lara, Marcelo Einicker-Lamas, Rogério Panizzutti, Caroline Madeira, Leucio D. Vieira-Filho, Carmen Castro-Chaves, Valdilene S. Ribeiro, Ana D. O. Paix?o, Emiliano Medei, Adalberto Vieyra
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100410
Abstract: Background Several studies have correlated protein restriction associated with other nutritional deficiencies with the development of cardiovascular and renal diseases. The driving hypothesis for this study was that Ang II signaling pathways in the heart and kidney are affected by chronic protein, mineral and vitamin restriction. Methodology/Principal Findings Wistar rats aged 90 days were fed from weaning with either a control or a deficient diet that mimics those used in impoverished regions worldwide. Such restriction simultaneously increased ouabain-insensitive Na+-ATPase and decreased (Na++K+)ATPase activity in the same proportion in cardiomyocytes and proximal tubule cells. Type 1 angiotensin II receptor (AT1R) was downregulated by that restriction in both organs, whereas AT2R decreased only in the kidney. The PKC/PKA ratio increased in both tissues and returned to normal values in rats receiving Losartan daily from weaning. Inhibition of the MAPK pathway restored Na+-ATPase activity in both organs. The undernourished rats presented expanded plasma volume, increased heart rate, cardiac hypertrophy, and elevated systolic pressure, which also returned to control levels with Losartan. Such restriction led to electrical cardiac remodeling represented by prolonged ventricular repolarization parameters, induced triggered activity, early after-depolarization and delayed after-depolarization, which were also prevented by Losartan. Conclusion/Significance The mechanisms responsible for these alterations are underpinned by an imbalance in the PKC- and PKA-mediated pathways, with participation of angiotensin receptors and by activation of the MAPK/ERK1/2 pathway. These cellular and molecular alterations culminate in cardiac electric remodeling and in the onset of hypertension in adulthood.
Early Double-Negative Thymocyte Export in Trypanosoma cruzi Infection Is Restricted by Sphingosine Receptors and Associated with Human Chagas Disease
Ailin Lepletier,Liliane de Almeida,Leonardo Santos,Luzia da Silva Sampaio,Bruno Paredes,Florencia Belén González,Célio Geraldo Freire-de-Lima,Juan Beloscar,Oscar Bottasso,Marcelo Einicker-Lamas,Ana Rosa Pérez,Wilson Savino,Alexandre Morrot
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0003203
Abstract: The protozoan parasite Trypanosoma cruzi is able to target the thymus and induce alterations of the thymic microenvironmental and lymphoid compartments. Acute infection results in severe atrophy of the organ and early release of immature thymocytes into the periphery. To date, the pathophysiological effects of thymic changes promoted by parasite-inducing premature release of thymocytes to the periphery has remained elusive. Herein, we show that sphingosine-1-phosphate (S1P), a potent mediator of T cell chemotaxis, plays a role in the exit of immature double-negative thymocytes in experimental Chagas disease. In thymuses from T. cruzi-infected mice we detected reduced transcription of the S1P kinase 1 and 2 genes related to S1P biosynthesis, together with increased transcription of the SGPL1 sphingosine-1-lyase gene, whose product inactivates S1P. These changes were associated with reduced intrathymic levels of S1P kinase activity. Interestingly, double-negative thymocytes from infected animals expressed high levels of the S1P receptor during infection, and migrated to lower levels of S1P. Moreover, during T. cruzi infection, this thymocyte subset expresses high levels of IL-17 and TNF-α cytokines upon polyclonal stimulation. In vivo treatment with the S1P receptor antagonist FTY720 resulted in recovery the numbers of double-negative thymocytes in infected thymuses to physiological levels. Finally, we showed increased numbers of double-negative T cells in the peripheral blood in severe cardiac forms of human Chagas disease.
Taxonomia zoológica no Brasil: estado da arte, expectativas e sugest?es de a??es futuras
Marques, Antonio Carlos;Lamas, Carlos José Einicker;
Papéis Avulsos de Zoologia (S?o Paulo) , 2006, DOI: 10.1590/S0031-10492006001300001
Abstract: brazil is a megadiverse developing country and the knowledge on the current situation of brazilian taxonomy is a necessary step to establish future policies to deal with biodiversity. certainly, the most important issue for the understanding of biodiversity is the installing capacity of taxonomists. in fact, little is known concerning the number of taxonomists, scientific production, and the problems faced by taxonomists in each country. once brazilian biota is the richest of the world, it is undisputable that its knowledge is critical to understand world biodiversity patterns and to base conservation policies. we produced a technical report on brazilian zoological taxonomy for the brazilian ministry of science and technology, which provided a more objective view upon the brazilian biodiversity challenge. brazil accounts for 6.67% of the total species described (ca. 100,000 out of 1.5 million), but we expect a significantly higher number of species to be described. brazil has 542 taxonomists: 415 with permanent positions, publishing in all fields of zoology. their average age is 45-50 years old, with the majority still expecting to be active for more than 15-20 years. phd theses in taxonomy decreased during the 1990s, reflecting the worlds lack of interest in the area. the majority of taxonomists are concentrated in south east (51.7%) and south (21.6%) brazil, and extensive regions, including biomes like pantanal, cerrado (savannah), caatinga and the amazonian rainforest, count with continuously fewer experts. taxa with the larger number of taxonomists are "fishes" (53), crustacea (39), diptera (28), and mollusca (27) although no taxon is considered to have enough experts. several groups are in a more critical situation. poorly known ecosystems and biomes are deep waters, continental shelf, northern coastline, semi-arid caatinga, amazon rainforest, though no region is considered adequately known. 7,320 species were described (1978-1995, 430/year), a rhythm very slow
Two new Southern African Apatomyza Wiedemann (Diptera, Bombyliidae, Crocidiinae) with discussion on their phylogenetic position
Lamas, Carlos José Einicker;Evenhuis, Neal L.;
Papéis Avulsos de Zoologia (S?o Paulo) , 2005, DOI: 10.1590/S0031-10492005002300001
Abstract: two new species of apatomyza wiedemann from south africa, a. whocantell spec. nov. and a. angusticephala spec. nov., are described, illustrated, and placed within the most recent key to species. into the data matrix recently used to infer a phylogenetic hypothesis for the subfamily, were added the two new taxa, in order to verify their position and relationships. they form the most apical clade in apatomyza.
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