Papers by Edvaldo Trindade
Revista Brasileira de Ortopedia (English Edition), 2014
r e v b r a s o r t o p . 2 0 1 4;4 9(1):62-68 w w w . r b o . o r g . b r Original article Effec... more r e v b r a s o r t o p . 2 0 1 4;4 9(1):62-68 w w w . r b o . o r g . b r Original article Effect of hyaluronic acids as chondroprotective in experimental model of osteoarthrosis ଝ,ଝଝ Hyaluronic acid Anterior cruciate ligament Knee Rabbits a b s t r a c t Objective: to analyze the effects of hyaluronic acid of different molecular weights in an experimental model of osteoarthritis in rabbits.
Revista Brasileira de Ortopedia, 2014
r e v b r a s o r t o p . 2 0 1 4;4 9(1):62-68 w w w . r b o . o r g . b r Artigo Original Efeito... more r e v b r a s o r t o p . 2 0 1 4;4 9(1):62-68 w w w . r b o . o r g . b r Artigo Original Efeito dos ácidos hialurônicos como condroprotetores em modelo experimental de osteoartrose ଝ informações sobre o artigo Histórico do artigo: Recebido em 3 de fevereiro de 2013 Aceito em 9 de abril de 2013 Palavras-chave: Osteoartrose Ácido hialurônico Ligamento cruzado anterior Joelho Coelhos r e s u m o Objetivo: analisar os efeitos do ácido hialurônico de diferentes pesos moleculares em modelo experimental de osteoartrose em coelhos. Métodos: foram alojados de modo aleatório 44 coelhos da raça California, machos, em três grupos (PR, S e P) e submetidos a ressecção do ligamento cruzado anterior do joelho direito. Decorridas três semanas do procedimento cirúrgico iniciaram-se as três injeç ões intraarticulares semanais de ácido hialurônico nativo (Polireumin ® )-PR, ácido hialurônico de cadeia ramificada (Synvisc ® )-S e soro fisiológico 0,9%-P. Todos os animais foram sacrificados após 12 semanas do ato cirúrgico e os platôs tibiais dos joelhos infiltrados foram dissecados. Cortes histológicos da cartilagem das áreas de apoio com maior espessura dos platôs tibiais foram corados com Alcian Blue pH = 1,0, Alcian Blue pH = 2,5 e Azul de Toluidina para pesquisa da quantidade de proteoglicanos. A intensidade de coloração foi quantificada em um aparelho de microscopia ZeissImager Z2 Metasystems e analisada pelo software Meta-ferMsearch. A análise estatística consistiu no uso dos testes Kolmorov-Smirnov, análise de variância (Anova), t de Student e qui-quadrado. O nível de significância usado foi de 5%. Resultado: o efeito condroprotetor dos ácidos hialurônicos usados no estudo foi demonstrado quando comparado ao do grupo controle, porém, feita a comparação entre si, não houve diferença estatística quanto à condroproteção. Conclusão: os ácidos hialurônicos testados obtiveram efeito condroprotetor, sem diferença estatística com relação aos diferentes pesos moleculares. r e v b r a s o r t o p . 2 0 1 4;4 9(1):62-68
Inhalation therapy with M1 inhibits experimental melanoma development and metastases in mice
Homeopathy, 2015
M1 is a homeopathic medicine with immunostimulatory properties used mainly by cancer patients to ... more M1 is a homeopathic medicine with immunostimulatory properties used mainly by cancer patients to complement current therapies. Metastatic melanoma is a skin-originated form of cancer without a single therapy able to produce high rate and sustained responses, which attracts the use of complementary therapies such as M1. However, M1's anti-melanoma effects remain to be pre-clinically demonstrated. Therefore in the present work, we utilized a pulmonary metastatic melanoma model and a subcutaneous melanoma growth model to investigate the potential benefits of treatment with M1. C57BL/6 mice were injected intravenously or subcutaneously with B16F10 mouse melanoma cells. After 24 h, mice were treated with either M1 or vehicle (water) for 14 days, euthanized and harvested for multi-parameter pulmonary and tumor analyses. Mice treated with M1 had significantly lower tumor burden in the lungs and subcutaneous tissue than control mice. Furthermore, tumors were impaired in proliferation and tumor related angiogenesis by the inhibition of myeloid derived suppressor cells (MDSC) positive for angiotensin II type 1 receptor (AT1R). Altogether these data suggest M1 is an efficient candidate for melanoma therapy to be considered for future clinic studies as this study is the first supporting the idea that melanoma patients may benefit with the treatment. The treatment with M1 provides advantages considering the highly-diluted properties and a cost effective alternative to costly chemotherapeutic approaches with, if any, lower toxicity.
Brown spider (Loxosceles intermedia) venom triggers endothelial cells death by anoikis
Toxicon, 2012
Brown spider (Loxosceles sp.) venom affects the endothelium of vessels and triggers disruptive ac... more Brown spider (Loxosceles sp.) venom affects the endothelium of vessels and triggers disruptive activity in the subendothelial matrix. The vascular disorders observed after venom exposure include leukocyte and platelet activation, disseminated intravascular coagulation, an increase in vessel permeability and hemorrhage into the dermis. In this study, we report additional evidence regarding the mechanism of endothelial cell cytotoxicity induced by Loxosceles intermedia venom. Exposure to venom led to endothelial cell detachment in a time-dependent manner. Loss of cell anchorage and cell-cell adhesion following venom exposure was accompanied by changes in the distribution of the α₅β₁ integrin and VE-cadherin. An ultrastructural analysis of cells treated with venom revealed morphological alterations characteristic of apoptosis. Moreover, after venom exposure, the ratio between Bax and Bcl-2 proteins was disturbed in favor of Bax. In addition, late apoptosis was only observed in cells detached by the action of venom. Accordingly, there was no increase in apoptosis when cells were exposed to L. intermedia venom in suspension, suggesting that the loss of cell anchorage provides the signal to initiate apoptosis. Thus, L. intermedia venom likely triggers endothelial cell death indirectly through an apoptotic mechanism known as anoikis.
The Journal of Immunology, 2003
Journal of Cellular Physiology, 2012
Endothelial cells (ECs) are a source of physiologically important molecules that are synthesized ... more Endothelial cells (ECs) are a source of physiologically important molecules that are synthesized and released to the blood and/or to the subendothelial extracellular matrix such as a heparan sulfate proteoglycan (HSPG) with antithrombotic properties. Previously, we have shown that heparin stimulates the synthesis and modifies the sulfation pattern of this HSPG. Here the molecular mechanisms involved in the up-regulation of HSPG synthesis by heparin in endothelial cells were decoded. The cells were stimulated with heparin and the expression of HSPG and intracellular pathways were evaluated by a combination of methods involving confocal microscopy, flow cytometry, Western blotting analyses, and [ 35 S]-sulfate metabolically labeling of the cells. We observed that the up-regulation of HSPG synthesis evoked by heparin is dependent on the interaction of heparin with integrin since RGD peptide abolishes the effect. The activation of integrin leads to tyrosine-phosphorylation of focal adhesion-associated proteins such as FAK, Src, and paxillin. In addition, heparin induces ERK1/2 phosphorylation and inhibitors of Ras and MEK decreased heparin-dependent HSPG synthesis. Moreover, heparin also induced intracellular Ca 2þ release, PLCg1 (phospholipase Cg1) and CaMKII (calcium calmodulin kinase II) activation, as well as an increase in nitric oxide (NO) production. Finally, an intracellular Ca 2þ chelator, Ca 2þ signaling inhibitors, and an endothelial NO synthase inhibitor were all able to abolish the effect in heparan sulfate synthesis. In conclusion, the heparin-induced up-regulation of HSPG expression is associated with the phosphorylation of focal adhesion proteins and Ras/Raf/MEK/ERK MAP and Ca 2þ /NO pathways.
Structural and Hemostatic Activities of a Sulfated Galactofucan from the Brown Alga Spatoglossum schroederi: AN IDEAL ANTITHROMBOTIC AGENT?
Journal of Biological Chemistry, 2005
The brown alga Spatoglossum schroederi contains three fractions of sulfated polysaccharides. One ... more The brown alga Spatoglossum schroederi contains three fractions of sulfated polysaccharides. One of them was purified by acetone fractionation, ion exchange, and molecular sieving chromatography. It has a molecular size of 21.5 kDa and contains fucose, xylose, galactose, and sulfate in a molar ratio of 1.0:0.5:2.0:2.0 and contains trace amounts of glucuronic acid. Chemical analyses, methylation studies, and NMR spectroscopy showed that the polysaccharide has a unique structure, composed of a central core formed mainly by 4-linked beta-galactose units, partially sulfated at the 3-O position. Approximately 25% of these units contain branches of oligosaccharides (mostly tetrasaccharides) composed of 3-sulfated, 4-linked alpha-fucose and one or two nonsulfated, 4-linked beta-xylose units at the reducing and nonreducing end, respectively. This sulfated galactofucan showed no anticoagulant activity on several "in vitro" assays. Nevertheless, it had a potent antithrombotic activity on an animal model of experimental venous thrombosis. This effect is time-dependent, reaching the maximum 8 h after its administration compared with the more transient action of heparin. The effect was not observed with the desulfated molecule. Furthermore, the sulfated galactofucan was 2-fold more potent than heparin in stimulating the synthesis of an antithrombotic heparan sulfate by endothelial cells. Again, this action was also abolished by desulfation of the polysaccharide. Because this sulfated galactofucan has no anticoagulant activity but strongly stimulates the synthesis of heparan sulfate by endothelial cells, we suggested that this last effect may be related to the "in vivo" antithrombotic activity of this polysaccharide. In this case the highly sulfated heparan sulfate produced by the endothelial cells is in fact the antithrombotic agent. Our results suggested that this sulfated galactofucan may have a potential application as an antithrombotic drug.
Chemico-Biological Interactions, 2013
Please cite this article in press as: G.L. Sassaki et al., Galactofuranosyl glycosides: Immunomod... more Please cite this article in press as: G.L. Sassaki et al., Galactofuranosyl glycosides: Immunomodulatory effects on macrophages and in vivo enhancement of lethality on sepsis, Chemico-Biological Interactions (2013), http://dx.doi.org/10.1016/j.cbi.2013.05.014 82 are dominant immunogenic structures, suggesting that hIntL is the 83 specific lectin for recognizing galactofuranosyl units. In addition, 84 immunomodulator properties have been reported for many glyco-85 conjugates and polysaccharides that contain Galf; therefore, these 86 polysaccharides are able to activate the innate immune system 87 in vitro and in vivo [3,4]. 88 Since many pathogenic microorganisms have conserved Galf 89 glycan epitopes, here we investigate several galactofuranoside 90 derivatives for their in vitro immunomodulation in peritoneal mac-91 rophages and in vivo activity of polymicrobial sepsis. 92 2. Materials and methods 93 2.1. Preparation of galactofuranosides 94 The chemical strategies were based on: (a) the influence of the 95 anomeric configuration, (b) the size of the aglycone substituent, 96 and (c) selective blocking of the HO-5, 6 groups of the Galf deriva-97 tives (Fig. 1). 98 Galactose (500 mg) and Me-b-Galp were obtained from Sigma-99 Aldrich, MO, USA. Commercial galactose was stirred in a methano-100 lic solution (MeOH-H 2 SO 4 , 99.5:0.5 v/v, 100 mL) at 25°C for 16 h 101 until complete dissolution [7]. The solution was neutralised with 102 aq. NH 4 OH and filtered to remove precipitated (NH 4 ) 2 SO 4 . Ammo-103 nium methyl sulphate was removed with Amberlite IR-400 (OH À ). 104 The two anomers were separated by chromatography on a column 105 (30 Â 2.0 cm diameter) packed with 60G silica gel (Merck), the 106 eluents being progressive mixtures of CHCl 3 -MeOH, which gave 107 pure methyl b-and a-galactofuranosides (GFB-Me and GFA-Me, 108 respectively).n-Octyl galactofuranosides were prepared from the 109 Me/Galf mixture (100 mg), which was dissolved in MeOH, and 110 n-octanol was then added to give a final solution (10 mL) contain-111 ing octanol-MeOH-H 2 SO 4 (100:10:0.5, v/v/v). This solution was 112 maintained for 48 h at 25°C, then neutralised and treated with 113 an anionic resin, as described above. Fractionation was performed 114 using the previous protocol, and n-octyl b-and a-galactofurano-115 sides (GFB-O and GFA-O, respectively) were eluted with 116 CHCl 3 -2-PrOH. 117 5,6-O-isopropylidene galactofuranosides were obtained by the 118 addition of a mixture of 2 mL acetone containing 0.1% H 2 SO 4 to a 119 4 mL glass vial, where the mixtures were maintained for 4 h at 120 room temperature. The solutions were then neutralised with 121 160 lL aqueous 25% NH 4 OH solution, the precipitates were filtered 122 off, and the supernatants were evaporated, giving rise to 5,6-O-iso-123 propylidene galactofuranosides, named GFA-Me-IP and GFB-Me-IP. 124 2.2. Spectrometric and spectroscopic analyses of the 125 G.L. Sassaki et al. / Chemico-Biological Interactions xxx (2013) xxx-xxx 7 CBI 6839 No. of Pages 9, Model 5G
Carbohydrate Polymers, 2013
Fucan is a term used to denominate sulfated l-fucose rich polysaccharides. Here, a heterofucan, n... more Fucan is a term used to denominate sulfated l-fucose rich polysaccharides. Here, a heterofucan, named fucan B, was extracted from the Spatoglossum schröederi seaweed. This 21.5 kDa galactofucan inhibited CHO-K1 proliferation and migration when fibronectin was the substrate. Fucan B derivatives revealed that such effects depend on their degree of sulfation. Fucan B did not induce cell death, but promoted G 1 cell cycle arrest. Western blotting and flow cytometry analysis suggest that fucan B binds to fibronectin and activates integrin, mainly integrin ␣51, which induces FAK/RAS/MEK/ERK activation. FAK activation inhibits CHO-K1 migration on fibronectin and ERK blocks cell cycle progression. This study indicates that fucan B could be applied in developing new antitumor drugs.
BMC Complementary and Alternative Medicine, 2011
Background: In the search for new therapies novel drugs and medications are being discovered, dev... more Background: In the search for new therapies novel drugs and medications are being discovered, developed and tested in laboratories. Highly diluted substances are intended to enhance immune system responses resulting in reduced frequency of various diseases, and often present no risk of serious side-effects due to its low toxicity. Over the past years our research group has been investigating the action of highly diluted substances and tinctures on cells from the immune system. Methods: We have developed and tested several highly diluted tinctures and here we describe the biological activity of M1, M2, and M8 both in vitro in immune cells from mice and human, and in vivo in mice. Cytotoxicity, cytokines released and NF-B activation were determined after in vitro treatment. Cell viability, oxidative response, lipid peroxidation, bone marrow and lymph node cells immunophenotyping were accessed after mice in vivo treatment. Results: None of the highly diluted tinctures tested were cytotoxic to macrophages or K562. Lipopolysaccharide (LPS)-stimulated macrophages treated with all highly diluted tinctures decreased tumour necrosis factor alpha (TNF-α) release and M1, and M8 decreased IFN-g production. M1 has decreased NF-B activity on TNF-α stimulated reporter cell line. In vivo treatment lead to a decrease in reactive oxygen species (ROS), nitric oxide (NO) production was increased by M1, and M8, and lipid peroxidation was induced by M1, and M2. All compounds enhanced the innate immunity, but M1 also augmented acquired immunity and M2 diminished B lymphocytes, responsible to acquired immunity. Conclusions: Based on the results presented here, these highly diluted tinctures were shown to modulate immune responses. Even though further investigation is needed there is an indication that these highly diluted tinctures could be used as therapeutic interventions in disorders where the immune system is compromised.
Development of an enzyme-linked immunosorbent assay for benalaxyl and its application to the analysis of water and wine
Analytica Chimica Acta, 1999
Development of an enzyme-linked immunosorbent assay (ELISA) using highly-specific monoclonal antibodies against plumbagin
Analytica Chimica Acta, 2008
Muscarinic Acetylcholine Receptors: Relevance to Infertility and Male Contraception
Immunology‚ Endocrine & Metabolic Agents in Medicinal Chemistry, 2008
... These effects were abolished by atropine, a nonselective mAChR antagonist [Siu et al., unpubl... more ... These effects were abolished by atropine, a nonselective mAChR antagonist [Siu et al., unpublished data]. ... 8, No. 1 47 Activated ERK1/2 phosphorylate both cytoplasmic and nuclear substrates, including many enzymes, cytoskeletal proteins and tran-scription factors. ...
Fish & Shellfish Immunology, 2014
The non-steroidal anti-inflammatory drugs are emerging contaminants in aquatic ecosystems. This s... more The non-steroidal anti-inflammatory drugs are emerging contaminants in aquatic ecosystems. This study aimed to evaluate toxic effects of some representative drugs of this pharmaceutical group on primary culture of monocytic lineage of Hoplias malabaricus anterior kidney. The effects of diclofenac, acetaminophen and ibuprofen in cell viability, lipopolysaccharide (LPS)-induced NO production and genotoxicity were evaluated. Cytometry analysis CD11b þ cells showed 71.5% of stem cells, 19.5% of macrophages and 9% of monocytes. Cell viability was lower in the ficoll compared to percoll separation. LPS-induced NO production by these cells was blocked after treatment with dexamethasone and NG-Methyl-L-Arginine (L-NMMA). Exposure of the cells to diclofenac (0.2e200 ng/mL), acetaminophen (0.025e250 ng/mL) ibuprofen (10e1000 ng/mL) reduced basal NO production and inhibited LPS-induced NO production at all concentrations after 24 h of exposure. Genotoxicity occurred at the highest concentration of diclofenac and at the intermediary concentration of acetaminophen. Genotoxicity was also observed by ibuprofen. In summary, the pharmaceuticals influenced NO production and caused DNA damage in monocytic cells suggesting that these drugs can induce immunosuppression and genotoxicity in fish.
Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2009
When environmental analysis is performed, the high number of samples required and handling condit... more When environmental analysis is performed, the high number of samples required and handling conditions during the transport of these samples to the laboratory are common problems. The comet assay is a useful, highly sensitive tool in biomonitoring. Some studies in the literature aim to preserve slides in lysis solution for use in the comet assay. Until now, however, no efficient
In Vivo and In Vitro Cytotoxicity of Brown Spider Venom for Blood Vessel Endothelial Cells
Thrombosis Research, 2001
The effect of brown spider (Loxosceles intermedia) venom on endothelial cells was investigated in... more The effect of brown spider (Loxosceles intermedia) venom on endothelial cells was investigated in vivo and in vitro. Morphological and ultrastructural observations by light microscopy and transmission electron microscopy showed that the venom acts in vivo upon vessel endothelial cells of rabbits that were intradermally injected, evoking vessel instability, cytoplasmic endothelial cell vacuolization, and blebs. Likewise, treatment of rabbit endothelial cells in culture with the venom led to loss of adhesion of the cells to the substrate. Endothelial cells in culture were metabolically radiolabeled with sodium [35S]-sulfate and the sulfated compounds (proteoglycans and sulfated proteins) from medium, cell surface, and extracellular matrix (ECM) were analyzed. Agarose gel electrophoresis and SDS-PAGE showed that the venom is active on the ECM and on cell surface proteoglycans, shedding these molecules into the culture medium. In addition, when purified heparan sulfate proteoglycan (HSPG) and purified laminin-entactin (LN/ET) complex were incubated with the venom we observed a partial degradation of the protein core of HSPG as well as the hydrolysis of entactin. The above results suggest that the L. intermedia venom has a deleterious effect on the endothelium of vessels both in vivo and in culture, removing important constituents such as HSPG and entactin that are involved in the adhesion of endothelial cells and of subendothelial ECM organization.
Toxicon, 2010
Bites from brown spider (Loxosceles genus) can cause several clinical manifestations, including n... more Bites from brown spider (Loxosceles genus) can cause several clinical manifestations, including necrotic skin degeneration with gravitational spread, renal failure and haematological disturbances . Whole venom is a mixture of protein-based toxins and several of these have been identified and characterized. Among these toxins are ribonucleotide phosphohydrolases, hyaluronidases, serineproteases, metalloproteases and phospholipases-D [2]. Loxosceles intermedia venom affects endothelial cell stability, which has been demonstrated both in vivo and in vitro. Histological analysis of rabbit skin sections after treatment with whole venom showed subendothelial vacuoles, bleb formation, endothelial cell membrane degeneration with vessel disruption, fibrin and thrombus formation and massive accumulation of polymorphonuclear leukocytes in and around blood vessels . Exposure of isolated endothelial cells (RAEC -rabbit aorta endothelial cell line) to venom toxins demonstrated morphological alterations such as cell retraction, an increase in filopodia projections and disadhesion to the extracellular matrix . These direct cytotoxic effects could indirectly lead to leukocyte and platelet activation, disseminated intravascular coagulation and an increase in vessel permeability . Preliminary data indicate that the deleterious effects on the vessel endothelium result not only from degradation of the extracellular matrix molecule or massive leukocyte infiltration, but also from a direct and primary activity of the venom on endothelial cells . The interaction between the Loxosceles intermedia venom toxins and the endothelial cell surface and their possible internalization were investigated in the present study. As a surface marker, we used WGA lectin (an Nacetylglucosamine and sialic acid binding lectin). After treating endothelial cells with venom toxins, we observed that the venom interacts with cell surface and cause a change in the distribution pattern of the WGA . The interaction of venom toxins with the cell surface also results in a reduction in the amount of cell surface glycoconjugates (data not shown). In order to determine if endothelial cells could internalize L. intermedia venom, the detection of venom toxins was performed after cell permeabilization, to allow the access of the polyclonal antibody to intracellular compartments. Fluorescent confocal microscopy visualization revealed the co-localization of venom with Lyso Tracker-Red DND-99 in lysosomes ( . Considering that endocytosis is blocked at low temperatures the LysoTracker-Red® DND-99 assay was repeated with the cells incubated with venom at 4°C for 1 h. The lack of intracellular venom toxin s at low temperatures strongly suggests that the venom toxins were internalizated by endocytosis . To confirm that the venom toxins were indeed being internalized by an endocytic process the fluorescent dye Lucifer Yellow (LY) was used to label endocytic vesicles. After endothelial cells were exposed to venom and LY for 1 h, both LY and venom were found in the same vesicles . Additionally, we investigated the possible disruption of the lipid bilayer of the endosomal/lysosomal vesicle membranes and subsequent rupture of lysosomes in RAEC cells after treatment with L. intermedia venom. For this purpose, cells were exposed to the venom and then incubated with acridine orange (AO). No difference in the intensity of red or green fluorescence was observed when compared treated cells to control cells . Both control and treated cells showed a red fluorescence that was restricted to lysosomes and a green fluorescence localized in the nuclear compartments without any noticeable co-localization of the red and green fluorescence, suggesting that the integrity of the lysosomal membrane was maintained after venom treatment. These data suggest that the endocytosis of venom toxins is not important for the damage in these cells, and the fate of the internalized venom inside the lysosomes most likely is degradation. These findings further our knowledge of the action mechanism of L. intermedia venom and provide new perspectives for the analyses of cytotoxicity effects of venom on endothelial cells.
Heparin and a Cyclic Octaphenol-Octasulfonic Acid (GL-522-Y-1) Bind With High Affinity to a 47-kDa Protein From Vascular Endothelial Cell Surface and Stimulate the Synthesis and Structural Changes of Heparan Sulfate Proteoglycan
Thrombosis Research, 2001
The effect of a cyclic octaphenol-octasulfonic acid (GL-522-Y-1), upon the synthesis of a heparan... more The effect of a cyclic octaphenol-octasulfonic acid (GL-522-Y-1), upon the synthesis of a heparan sulfate proteoglycan synthesized by endothelial cells (rabbit aorta and human umbilical vein) were studied. The cells were exposed to the compounds at various concentrations for different periods of time and the synthesized heparan sulfates analyzed by a combination of agarose gel electrophoresis and enzymatic degradation. The GL-522-Y-1, like heparin, change the sulfation pattern and stimulate two- to three-fold the synthesis of heparan sulfate proteoglycan secreted by rabbit and human endothelial cells in culture. GL-522-Y-1, besides being 100 times more active than heparin, also produces a significant enhancement of cell surface heparan sulfate in human vein endothelial cells. The effect of GL-522-Y-1 is completely abolished by methylation or acetylation of its free hydroxyl groups. Both heparin and GL-522-Y-1 have high affinity for a 47-kDa protein present at the surface of endothelial cells. These and other results lead us to speculate that the antithrombotic activity of heparin and GL522 "in vivo" could be related, at least in part, to the increased production of the heparan sulfate proteoglycan by endothelial cells.
Fucan Inhibits Chinese Hamster Ovary Cell (CHO) Adhesion to Fibronectin by Binding to the Extracellular Matrix
Planta Medica, 2005
In recent years, sulfated fucans have emerged as an important class of natural biopolymers. In th... more In recent years, sulfated fucans have emerged as an important class of natural biopolymers. In this study, the anti-adhesive activity of a fucan from the brown seaweed Spatoglossum schröederi was analyzed using tumorigenic cells: wild-type Chinese hamster ovary cells (CHO-K1) and the mutant type deficient in xylosyltransferase (CHO-745). Fibronectin (FN) was used as substrate for cell attachment. For both cell types, this fucan has shown a dose-dependent anti-adhesive effect, reaching saturation at around 400 mug/mL. This effect was abolished by desulfation of the fucan. In addition, this polymer exhibited the highest inhibitory effect in comparison to other sulfated polysaccharides. The fucan was biotinylated and used as a probe to identify its action sites. Biotinylated fucan was detected in the extracellular matrix environment by confocal microscopy and flow cytometric analysis, but not at the cell surface. The results suggest that the fucan shows anti-adhesive activity by binding directly to FN, and blocking FN sites that are recognized by cell surface ligands, possibly the integrin family.
Parasitology International, 2006
Parasitic flatworms present several steps of body architecture rearrangement during their fast tr... more Parasitic flatworms present several steps of body architecture rearrangement during their fast transition from one developmental stage to another, which are, at least in part, responsible for their evasion from host immune response. Besides, different developmental stages present different degrees of susceptibility to drug action, and the identification of more susceptible stages is of importance for the definition of therapeutical approaches. Mesocestoides corti (syn. Mesocestoides vogae) is considered a good model to study cestode biology because it can be easily manipulated both in vivo and in vitro and due to its relatively close relationship to cestodes of medical relevance, such as those from genera Echinococcus or Taenia. We have analyzed the damaging action of two broad spectrum anthelmintic drugs (praziquantel and albendazole) throughout the in vitro strobilization process of M. corti in order to identify developmental stages or body structures more susceptible to these drugs. Tetrathyridia (larval stage) and segmented-induced worms were cultivated and treated with praziquantel and albendazole. Whole mounted samples, taken from different developmental stages, were fixed and stained with fluorophore-labeled WGA lectin and phalloidin for the analysis of tegument and muscles, respectively. Confocal laser scanning microscopy was used to identify anatomical changes and lesions caused by each anthelmintic drug in a 3D view. We demonstrated that both praziquantel and albendazole cause extensive tissue damage, especially on tegument, and that adult forms were the most susceptible to drug exposure.
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Papers by Edvaldo Trindade