RÉSUMÉ
Uma área de pesquisa que vem ganhando muita atenção nos últimos anos é a nanomedicina, com especial atenção para os sistemas com entrega controlada de fármacos, ou drug delivery. Dentre as diversas nanopartículas utilizadas para este fim, destacam-se os sistemas formados por lipídeos e polímeros, como por exemplo os lipossomos e os cubossomos. Neste trabalho, é estudada a influência estrutural da lisozima e da curcumina, proteínas modelo. A lisozima é uma enzima antimicrobiana produzida por animais e que faz parte do sistema imunológico. Ela é uma hidrolase glicosídica que catalisa a hidrólise dos componentes da parede celular de bactérias gram-positivas. Esta hidrólise, por sua vez, compromete a integridade das paredes celulares, causando a lise (e como consequência a morte) das bactérias. Curcumina é um composto cristalino de cor amarelada brilhante, encontrada no caule da Curcuma longa (ou açafrão), que tem sido utilizada como corante ou até mesmo como aditivo alimentar. Este composto tem sido uma grande aposta no tratamento de doenças crônicas como inflamação, artrite, síndrome metabólica, doença hepática, obesidade, doenças neurodegenerativas e principalmente canceres, sendo também utilizada em estudos como potencial agente antibacteriano. O principal objetivo deste trabalho é construir sistemas nanoestruturados com potencial de atuarem como sistemas antimicrobianos, com a liberação controlada de ambos dos fármacos. Estes sistemas são compostos por cubossomos de fitantriol (PHY) em ausência e presença da lisozima, da curcumina e de suas combinações, a fim de analisar ação antimicrobiana conjunta da lisozima e da curcumina. As técnicas biofísicas utilizadas para caracterizar essas partículas são SAXS (espalhamento de raios-X em baixos ângulos), DLS (espalhamento dinâmico de luz), Cryo-TEM (criomicroscopia eletrônica de transmissão) e NTA (análise de rastreamento de nanopartículas). Foi possível verificar que as formulações lipídicas são eficazes na formação de estruturas cúbicas com estabilidade desejável. As nanopartículas cúbicas demonstraram alta capacidade de encapsulação da lisozima e da curcumina. A cinética de liberação desses medicamentos mostrou-se promissora, sugerindo que a encapsulação dos fármacos é eficaz, bem como a liberação controlada e direcionada. Duas linhagens de bactérias foram estudadas, sendo que a E. coli, não sofreu nenhum dano citotóxico, enquanto a Bacillus subtilis sim. Tal resultado indica o potencial antimicrobiano do sistema para alguns tipos de bactérias
An area of research that has gained significant attention in recent years is nanomedicine, with a particular focus on drug delivery systems. Among the various nanoparticles used for this purpose, lipid and polymer-based systems, such as liposomes and cubosomes stand out. This study investigate the structural influence of encapsulating lysozyme and curcumin, model compounds. Lysozyme is an antimicrobial enzyme produced by animals and is part of the immune system. It is a glycosidic hydrolase that catalyzes the hydrolysis of components in the cell walls of gram-positive bacteria. This hydrolysis compromises the integrity of cell walls, leading to the lysis (and consequently the death) of bacteria. Curcumin is a bright yellow crystalline compound found in the stem of Curcuma longa (or turmeric), commonly used as a dye or even as a food additive. It has been a significant focus in the treatment of chronic diseases such as inflammation, arthritis, metabolic syndrome, liver disease, obesity, neurodegenerative diseases, and especially cancers. It is also studied as a potential antibacterial agent. The main objective of this study is to construct nanostructured systems with the potential to act as antimicrobial agents, with controlled release of both drugs. These systems consist of phytantriol (PHY) cubosomes in the absence and presence of lysozyme, curcumin, and their combinations to analyze the joint antimicrobial action of lysozyme and curcumin. Biophysical techniques used for characterization include Small-Angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS), Cryo-Transmission Electron Microscopy (Cryo-TEM), and Nanoparticle Tracking Analysis (NTA). It was observed that lipid formulations are effective in forming cubic structures with desirable stability. Cubic nanoparticles have demonstrated a high encapsulation capacity for lysozyme and curcumin. The release kinetics of these drugs have shown promise, suggesting that drug encapsulation is effective, as well as their controlled and targeted release. Two bacterial strains were studied, with E. coli showing no cytotoxic damage, while Bacillus subtilis did. This result indicates the antimicrobial potential of the system against types of bacteria
Sujet(s)
Lysozyme/effets indésirables , Curcumine/effets indésirables , Additifs alimentaires/classification , Bacillus subtilis/classification , Préparations pharmaceutiques/analyse , Maladie chronique/prévention et contrôle , Microscopie électronique en transmission à balayage/méthodes , Cryomicroscopie électronique/méthodes , Microscopie électronique à transmission/méthodes , Agents colorants/classification , Anti-infectieux/effets indésirablesRÉSUMÉ
Abstract Compound Danshen Dripping Pills (CDDPs) have been used in clinical treatment to protect the heart from ischemia/reperfusion (IR) injury for many years. However, the underlying mechanism implicated in the protective effects remains to be explored. Here, we determined the effects of CDDPs in Sprague-Dawley rats with the IR model. Cardiac function in vivo was assessed by echocardiography. Transmission electron microscopy, histological and immunohistochemical techniques, Western blotting and recombinant adeno-associated virus 9 transfection were used to illustrate the effects of CDDPs on IR and autophagy. Our results showed that pretreatment with CDDPs decreased the level of serum myocardial enzymes and infarct size in rats after IR. Apoptosis evaluation showed that CDDPs significantly ameliorated the cardiac apoptosis level after IR. Meanwhile, CDDPs pretreatment increased myocardial autophagic flux, with upregulation of LC3B, downregulation of p62, and increased autophagosomes and autolysosomes. Moreover, the autophagic flux inhibitor chloroquine could increase IR injury, while CDDPs could partially reverse the effects. Furthermore, our results showed that the activation of AMPK/mTOR was involved in the cardioprotective effect exerted by CDDPs. Herein, we suggest that CDDPs partially protect the heart from IR injury by enhancing autophagic flux through the activation of AMPK/mTOR.
Sujet(s)
Animaux , Mâle , Rats , Reperfusion/classification , Lésion d'ischémie-reperfusion/classification , Technique de Western/instrumentation , Coeur/physiopathologie , Ischémie/classification , Échocardiographie/méthodes , Microscopie électronique à transmission/méthodes , Infarctus/anatomopathologieRÉSUMÉ
Abstract To explore the effects and mechanisms of benzoylaconitine and paeoniflorin on collagen-induced arthritis (CIA) rats. Weight, paw swelling, arthritis index and joint pathologic changes were examined in each group after CIA induction. PGE2, IL-1ß, IL-6, IL-10, TNF-α, VEGF, MMP-3, IgG and anti-CII Ab were assessed by ELISA; STAT1 and STAT3 expressions were analyzed immunohistochemically, and the ultrastructure of synovial cells was observed by transmission electron microscopy. Therapeutic effects were determined in CIA rats via injecting benzoylaconitine and paeoniflorin, which could alleviate the degree of swelling and arthritis index (AI) and pathological lesions of the sacroiliac gland; decrease the levels of PGE2, IL-1ß, TNF-α, VEGF and IgG in serum; reduce STAT1 and STAT3 expression in the membrane tissue; and inhibit the secretion and proliferation of synovial cells. These results showed that benzoylaconitine and paeoniflorin could significantly palliate the arthritic symptoms of CIA rats, and better therapeutic effects could be achieved if the two components were used in combination
Sujet(s)
Animaux , Mâle , Rats , Arthrite expérimentale/induit chimiquement , Utilisations thérapeutiques , Test ELISA/méthodes , Dinoprostone/effets indésirables , Interleukine-6/pharmacologie , Interleukine-1/pharmacologie , Interleukine-10/pharmacologie , Matrix metalloproteinases , Microscopie électronique à transmission/méthodesRÉSUMÉ
A Leucemia Linfoide Aguda (LLA) é um câncer de maior incidência em crianças, e tem a Lasparaginase (ASNase) como fármaco amplamente utilizado no tratamento dos afetados. A ASNase catalisa a hidrólise do aminoácido L-asparagina (Asn), presente na corrente sanguínea, a ausência do aminoácido no meio extracelular leva à morte células leucêmicas, que necessitam deste aminoácido para as funções celulares. Fatores envolvendo a eficiência do tratamento com ASNase como reações adversas e curta meia-vida, principalmente devido ao reconhecimento pelo sistema imune e degradação por proteases, limitam a sua eficácia. A encapsulação da enzima em lipossomas pode conferir proteção à degradação, melhorar seu perfil farmacocinético e diminuir os efeitos adversos, de forma a melhorar o tratamento da LLA sendo este o objetivo desse trabalho. Lipossomas de DOPC (1,2-dioleoil-sn-glicero-3-fosfocolina) e DMPC (1,2-dimiristoil-snglicero-3-fosfocolina) foram desenvolvidos empregando-se o método de hidratação do filme lipídico e diferentes protocolos de preparo contendo ou não diferentes concentrações de 18:0 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polietilenogicol)-2000] (DSPE-PEG). Os lipossomas produzidos foram utilizados para encapsular a ASNase e os sistemas contendo ou não ASNase encapsulada foram caracterizados por espalhamento de luz dinâmico (DLS), potencial zeta, microscopia eletrônica de transmissão (MET) e criomicroscopia de transmissão. Adicionalmente, foram avaliados a taxa de encapsulação e o perfil de permeabilidade das vesículas à L-asparagina. As análises de DLS mostraram que as nanoestruturas formadas empregando-se agitação magnética a partir de sistemas contendo 10% e 20% de DSPE-PEG possuem diâmetro hidrodinâmico menor (~ 25 nm a 60 nm) que os mesmos sistemas sem o fosfolipídio peguilado (~190 nm a 222 nm), demonstrando a relação entre a diminuição do tamanho e o aumento da quantidade de fosfolipídio peguilado e possível formação de estruturas micelares ou bicelares. O emprego de agitação em vórtex para hidratação do filme lipídico, adição do antioxidante -tocoferol e redução da concentração de DSPE-PEG (5% e 10%) levou à formação de sistemas com diâmetro hidrodinâmico maior, sendo esse protocolo e concentrações de PEG definidos como padrão. As análises de MET comprovaram a formação de lipossomas com diâmetro hidrodinâmico semelhante ao observado por DLS; com a utilização da criomicroscopia foi possível observar os lipossomas sem deformações. Os lipossomas de DMPC/DSPE-PEG 10% apresentaram maior permeabilidade à L-asparagina ao longo do tempo e, portanto, poderiam funcionar como nanoreatores, depletando o aminoácido da circulação. Estudos in vitro com células tumorais devem ser realizados e em seguida estudos in vivo, para confirmar este potencial
L-asparaginase (ASNase) is a first-choice drug, combined with other drugs, in therapeutic schemes to treat Acute Lymphoblastic Leukemia (ALL) in children and adolescents. ASNase catalyzes the hydrolysis of L-asparagine (Asn) in the bloodstream; since ALL cells cannot synthesize this amino acid, protein synthesis is impaired leading to leukemic cells death by apoptosis. In spite of its therapeutic importance, treatment with ASNase is associated to side effects, mainly hypersensitivity and immunogenicity. Another drawback refers to degradation by plasma proteases that altogether with immunogenicity shortens the enzyme half-life. Encapsulation of ASNase in liposomes, vesicular nanostructures formed by the self-aggregation of phospholipids, is an attractive alternative that possibly will protect the enzyme from plasma proteases, resulting on better pharmacokinetics profile. In this work, we prepared by thin film hydration liposomal formulations of the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-dimyristoyl-sn-glycero-3- phosphocholine (DMPC) containing or not different concentrations of 18:0 1,2-distearoyl-snglycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG), and encapsulated ASNase by electroporation. The systems containing or not ASNase were analyzed by Dynamic Light Scattering, zeta potential and Electron Microscopy. The encapsulation efficiency and vesicles permeability were also evaluated. According to the DLS analysis, the nanostructures formed by film hydration under magnetic stirring employing 10% or 20% DSPE-PEG presented smaller hydrodynamic diameter (~ 25 nm to 60 nm) than the same systems without the pegylated phospholipid (~ 190 nm to 222 nm), demonstrating the relation between size and the amount of pegylated phospholipid that results in formation of micellar or bicellar structures. The protocol was stabilize by hydration of the lipid film under vortex agitation, addition of the antioxidant - tocopherol and reduction of the concentration of DSPE-PEG (5% and 10%), what altogether led to the formation of nanostructures of higher hydrodynamic diameter and monodisperse systems. TEM analyzes confirmed the formation of liposomes with hydrodynamic diameter similar to that observed by DLS; with the use of cryomicroscopy it was possible to observe the liposomes without deformations. Liposomes of DMPC/DSPE-PEG 10% showed permeability to L-asparagine over time and, therefore, could function as nanoreactors, depleting the circulating amino acid
Sujet(s)
Asparaginase/pharmacologie , Liposomes/analyse , Asparagine/antagonistes et inhibiteurs , Techniques in vitro/instrumentation , Préparations pharmaceutiques/analyse , Microscopie électronique/méthodes , Microscopie électronique à transmission/méthodes , Leucémie-lymphome lymphoblastique à précurseurs B et T/anatomopathologie , Antioxydants/effets indésirablesRÉSUMÉ
Abstract In this work, polystyrene-b-poly (acrylic acid) (PS-b-PAA) nanovesicles were coated by modified chitosans aiming at studying its physicochemical parameters. The chitosan (CS) was chemically modified to add hydrophilic and/or hydrophobic groups, obtaining three modified chitosans. The PS-b-PAA nanovesicles were obtained by organic (1,4-dioxane) cosolvent method in water, resulting in nanovesicles with less than 150 nm of diameter (polydispersibility index - PDI at 90° = 0.106), measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM), and negative zeta potential (-37.5 ± 3.2 mV), allowing the coating of its surface with oppositely charged polysaccharides, such as the CS and the modified chitosans. The coating process was made by mixing the colloidal suspensions with the CS and the modified chitosans at specific ENT#091;CS-xENT#093;/ENT#091;PS-b-PAAENT#093; ratios (0.001 to 1.0 wt %) and measuring the change in size and surface charge by DLS and zeta potential. Upon reaching maximum adsorption, the zeta potential parameter was positively stabilized (+26.7 ± 4.1 mV) with a hydrodynamic diameter slightly longer (< 200 nm of diameter). The encapsulation efficiency (EE) of minoxidil, quantified by capillary electrophoresis, was 50.7%, confirming their potential as drug delivery carriers and the coating process showed the possibility of controlling the surface charge nature of these nanovesicles
Sujet(s)
Chitosane/métabolisme , Minoxidil/analogues et dérivés , Microscopie électronique à transmission/méthodes , Rendement/classification , Diffusion dynamique de la lumière/instrumentation , MéthodesRÉSUMÉ
ABSTRACT Lisch corneal dystrophy is a rare corneal disease characterized by the distinctive feature of highly vacuolated cells. Although this feature is important, the nature of these vacuoles within corneal cells remains unknown. Here, we sought to analyze corneal cells from a patient diagnosed with Lisch dystrophy to characterize the vacuoles within these cells. Analyses using histopathology examination, confocal microscopy, and transmission electron microscopy were all consistent with previous descriptions of Lisch cells. Importantly, the vacuoles within these cells appeared to be autophagosomes and autolysosomes, and could be stained with an anti-microtubule-associated protein 1A/1B-light chain 3 (LC3) antibody. Taken together, these findings indicate that the vacuoles we observed within superficial corneal cells of a patient with Lisch corneal dystrophy constituted autophagosomes and autolysosomes; this finding has not been previously reported and suggests a need for further analyses to define the role of autophagy in this ocular disease.
RESUMO A distrofia corneana de Lisch é uma doença rara, caracterizada principalmente pela presença de células altamente vacuoladas. Embora esta característica seja importante, a natureza desses vacúolos dentro das células da córnea permanece des conhecida. Aqui, procuramos analisar as células da córnea de um paciente diagnosticado com distrofia de Lisch para caracte rizar os vacúolos dentro dessas células. Análises utilizando exame histopatológico, microscopia confocal e microscopia eletrônica de transmissão foram todas consistentes com descrições previas de células de Lisch. Importante, os vacúolos dentro dessas células pareciam ser autofagossomos e autolisossomos, e po deriam ser corados com um anticorpo proteico 1A/1B-cadeia leve 3 (LC3) da proteína anti-microtúbulo associado a microtúbulos. Em conjunto, esses achados indicam que os vacúolos observados nas células superficiais da córnea de um paciente com distrofia corneana de Lisch constituíram autofagossomos e autolisossomos. Esse achado não foi relatado anteriormente e sugere a necessidade de mais análises para definir o papel da autofagia nessa doença ocular.
Sujet(s)
Humains , Femelle , Adulte , Vacuoles/anatomopathologie , Dystrophies héréditaires de la cornée/anatomopathologie , Autophagosomes/anatomopathologie , Dystrophies héréditaires de la cornée/imagerie diagnostique , Microscopie confocale/méthodes , Opacité cornéenne/anatomopathologie , Opacité cornéenne/imagerie diagnostique , Tomographie par cohérence optique/méthodes , Microscopie électronique à transmission/méthodes , MicroautophagieSujet(s)
Humains , Mâle , Adulte d'âge moyen , Chaines légères kappa des immunoglobulines/analyse , Podocytes/immunologie , Maladies du rein/immunologie , Tubules contournés proximaux/immunologie , Paraprotéinémies/complications , Dexaméthasone/usage thérapeutique , Résultat thérapeutique , Créatinine/sang , Cristallisation , Cyclophosphamide/usage thérapeutique , Microscopie électronique à transmission/méthodes , Diagnostic différentiel , Albuminurie/étiologie , Association de médicaments , Podocytes/anatomopathologie , Podocytes/ultrastructure , Atteinte rénale aigüe/diagnostic , Bortézomib/usage thérapeutique , Maladies du rein/imagerie diagnostique , Tubules contournés proximaux/ultrastructure , Anti-inflammatoires/usage thérapeutique , Antinéoplasiques/usage thérapeutiqueRÉSUMÉ
Con la finalidad de evaluar la patogenia en cepas de Salmonella Typhimurium con mutaciones en los genes invG/invE de la Isla de Patogenicidad de Salmonella 1 (SPI-1) y de los genes ssaJ/ssaK en la SPI-2, se evaluaron los modelos asa intestinal ligada de ratón asociado a la observación de los tejidos por microscopía electrónica de transmisión (MET) y la producción de salmonelosis sistémica en ratón. Para ello, se utilizaron seis cepas de Salmonella: S. Typhimurium SL-1344 (cepa control) y sus derivadas mutantes: ∆invEG S. Typhimurium SL-1344 (mutante en SPI-1) y ∆ssaJK S. Typhimurium SL-1344 (mutante en SPI-2), S. Typhimurium (cepa clínica) y sus derivadas mutantes: ∆invEG S. Typhimurium y ∆ssaJK S. Typhimurium. Los resultados de MET permitieron verificar las alteraciones morfológicas del epitelio intestinal en el ratón infectado con cepas de Salmonella cuyos genes de patogenicidad estaban intactos. Fue comprobada la pérdida del poder invasivo solo en las cepas mutadas en la SPI-1. A través del modelo de salmonelosis sistémica en ratón se pudo comprobar la pérdida de la capacidad de diseminación en ambas mutantes. En conclusión los modelos permitieron verificar la importancia que tienen los genes invG/invE de la SPI-1 y ssaJ/ssaK de la SPI-2 en la patogenia de la salmonelosis, utilizando como modelo experimental de infección ratones BALB/c. Se sugieren estos modelos in vivo para evaluar mutantes de genes implicados en la patogenia de Salmonella, ya que representan una herramienta importante para la comprensión de la interacción Salmonella-hospedero(AU)
With the aim of evaluate the pathogenesis in Salmonella Typhimurium strains with mutations in genes invG/invE of Salmonella Pathogenicity Island 1 (SPI-1) and genes ssaJ/ssaK in the SPI-2 models were evaluated ligated intestinal loop associated mouse tissues by observation by transmission electron microscopy (TEM) and the production of mouse systemic salmonellosis. For this, we used six Salmonella strains: S. Typhimurium SL-1344 (control strain) and its derived mutants: ΔinvEG S. Typhimurium SL-1344 (mutant in SPI-1) and ΔssaJK S. Typhimurium SL-1344 (mutant in SPI-2), S. Typhimurium (clinical isolate) and its derived mutants: ΔinvEG S.Typhimurium and ΔssaJK S. Typhimurium. TEM results allowed us to verify the morphological alterations of the intestinal epithelium in mice infected with Salmonella strains whose pathogenicity genes were intact. It was proven invasive power loss only in strains mutated in the SPI-1. Through systemic salmonellosis model mouse we noted the loss of the ability to spread in both mutants. In conclusion, the models allowed us to verify the importance of the invG/invE genes of SPI-1 and ssaJ/ssaK of SPI-2 in the pathogenesis of salmonellosis, using BALB/c mice as an experimental model of infection. These in vivo models are suggested to evaluate mutants of genes involved in the pathogenesis of Salmonella, since they represent an important tool for the understanding of the Salmonella-host interaction(AU)
Sujet(s)
Animaux , Souris , Salmonella typhimurium/pathogénicité , Ilots génomiques/génétique , Microscopie électronique à transmission/méthodes , Mutation/génétiqueRÉSUMÉ
Abstract In Dentistry, restorative materials and oral bacteria are believed to be responsible for restoration failure. To make long-lasting restorations, antibacterial agents should be made. Inorganic nanoparticles and their nano composites are applied as good antibacterial agents. Objective The purpose of this study was to investigate the effect of silver nanoparticles on composite shear bond strength using one etch and rinse and one self-etch adhesive systems. Material and Methods Silver nanoparticles were prepared. Transmission electron microscope and X-ray diffraction were used to characterize the structure of the particles. Nanoparticles were applied on exposed dentin and then different adhesives and composites were applied. All samples were tested by universal testing machine and shear bond strength was assesed. Results Particles with average diameter of about 20 nm and spherical shape were found. Moreover, it was shown that pretreatment by silver nanoparticles enhanced shear bond strength in both etch and rinse, and in self-etch adhesive systems (p≤0.05). Conclusions Considering the positive antibacterial effects of silver nanoparticles, using them is recommended in restorative dentistry. It seems that silver nanoparticles could have positive effects on bond strength of both etch-and-rinse and self-etch adhesive systems. The best results of silver nanoparticles have been achieved with Adper Single Bond and before acid etching.
Sujet(s)
Humains , Argent/composition chimique , Collage dentaire/méthodes , Céments résine/composition chimique , Ciments dentaires/composition chimique , Dentine/effets des médicaments et des substances chimiques , Nanoparticules métalliques/composition chimique , Valeurs de référence , Argent/pharmacologie , Propriétés de surface/effets des médicaments et des substances chimiques , Mordançage à l'acide/méthodes , Diffraction des rayons X/méthodes , Test de matériaux , Reproductibilité des résultats , Analyse de variance , Résistance au cisaillement/effets des médicaments et des substances chimiques , Dentine/composition chimique , Microscopie électronique à transmission/méthodes , Antibactériens/composition chimiqueRÉSUMÉ
In cell culture, cell structures suffer strong impact due to centrifugation during processing for electron microscope observation. In order to minimise this effect, a new protocol was successfully developed. Using conventional reagents and equipments, it took over one week, but cell compression was reduced to none or the lowest deformation possible.
Sujet(s)
Animaux , Aedes/ultrastructure , Virus de la dengue/ultrastructure , Microscopie électronique à transmission/méthodes , Aedes/virologie , Techniques de culture cellulaire , Centrifugation/méthodes , Chlorocebus aethiops , Fixateurs , Indicateurs et réactifs , Cellules Vero/ultrastructureRÉSUMÉ
In embedment-free transmission electron microscopy without employing epoxy embedding media, the cytoplasmic matrix, in which cell organelles and elements including the cytoskeletons are held in place, lattices of strands are clearly and constantly disclosed in every cell. Their compactness is variable in different kinds of cells and in different domains of one and the same cell, and it is changeable under hypo- or hyper-osmolarity. In addition, the appearance of strand-lattices is duplicable in artificial proteins at different sol/gel states and concentrations. All taken together, a new and probable ultrastructural criteria has been proposed for identification of cytoplasmic sol/gel states with a hope that the dynamic properties of the cell is understood not only by the cytoskeleton but also by the sol/gel states of cytosolic proteins and their concentration in distinct association with cellular ultrastructural entities.
En microscopía electrónica de transmisión, la inclusión-libre sin el uso de medios de inclusión epoxi, la matriz citoplasmática (los orgánulos celulares y elementos, incluyendo los citoesqueletos) se mantienen en su lugar y las redes de hebras aparecen claramente y constantemente en cada célula. Su tamaño compacto es variable en diferentes tipos de células y en diferentes dominios de una y la misma célula, y es modificable bajo hipo o hiper-osmolaridad. Además, la aparición de redes de hebras es duplicable en las proteínas artificiales en diferentes estados de concentraciones sol / gel. En este contexto se ha propuesto un criterio ultraestructural nuevo y probable para la identificación de los estados sol / gel citoplasmáticos, con el objetivo de que las propiedades dinámicas de la célula se comprendan no solo a partir del citoesqueleto, sino también a partir de los estados sol / gel de proteínas citosólicas y su concentración en relación con una asociación indistinta con las entidades celulares ultraestructurales.
Sujet(s)
Cytoplasme/ultrastructure , Microscopie électronique à transmission/méthodes , Gels , Inclusion de tissuRÉSUMÉ
El uso creciente de nanomateriales en productos industriales y de consumo ha incrementado la preocupación mundial respecto a sus posibles efectos adversos en los sistemas biológicos. Como consecuencia de la falta de un marco legislativo y la ausencia de un consenso sobre los protocolos experimentales, las investigaciones ecotoxicológicas se llevan a cabo a un ritmo mucho más lento que la producción de nuevas nanopartículas. Por esta razón, existe una necesidad creciente de realizar estudios que aporten conocimiento sobre el riesgo de estos contaminantes emergentes de propiedades únicas. El objetivo del presente trabajo fue evaluar la frecuencia de micronúcleos (FMN) en eritrocitos de ejemplares juveniles de pacú (Piaractus mesopotamicus) expuestos a nanopartículas de plata (Nano-Ag) a las concentraciones de 0 μg·L-1 (control); 2,5 μg·L-1; 10 μg·L-1; y 25 μg·L-1, durante 24 horas. Se observó que la FMN se incrementó significativamente (p<0,01) en la concentración de 25 μg·L-1, mientras que no hubo diferencias significativas entre los grupos expuestos a 2,5 y 10 μg·L-1 y el control. Estos resultados sugieren que los eventos aneugénicos o clastogénicos podrían representar un posible mecanismo de toxicidad de Nano-Ag en esta especie.
The growing use of nanomaterials in consumer and industrial products has aroused global concern about possible adverse effects on biological systems. Due to the lack of a regulation framework and the absence of a consensus on the experimental protocols, ecotoxicological investigations are carried out much slower than the production of new nanoparticles. For this reason, there is a growing need for studies that provide knowledge about the risk of these emerging contaminants of unique properties. The objective of the present study was to evaluate the frequency of micronuclei (FMN) in erythrocytes of juvenile Piaractus mesopotamicus exposed to silver nanoparticles (nano-Ag; Nanotek SA) at concentrations of 0 μg·L-1 (control); 2.5 μg·L-1; 10 μg·L-1; and 25 μg·L-1, for 24 hours (n = 10 per treatment). The FMN show a significant increase (p <0.01) in fish exposed to 25 μg·L-1 of Nano-Ag, while there were no significant differences among the groups exposed to 2.5 and 10 μg·L-1 with the control. These results suggest that the aneugenics or clastogenics events may represent a possible mechanism of toxicity of Nano-Ag in this specie.
Sujet(s)
Nanoparticules métalliques/toxicité , Tests de micronucleus/méthodes , Microscopie électronique à transmission/méthodes , Tests de mutagénicité/statistiques et données numériquesRÉSUMÉ
Background: Circulatory power (CP) and ventilatory power (VP) are indices that have been used for the clinical evaluation of patients with heart failure; however, no study has evaluated these indices in patients with coronary artery disease (CAD) without heart failure. Objective: To characterize both indices in patients with CAD compared with healthy controls. Methods: Eighty-seven men [CAD group = 42 subjects and healthy control group (CG) = 45 subjects] aged 40–65 years were included. Cardiopulmonary exercise testing was performed on a treadmill and the following parameters were measured: 1) peak oxygen consumption (VO2), 2) peak heart rate (HR), 3) peak blood pressure (BP), 4) peak rate-pressure product (peak systolic HR x peak BP), 5) peak oxygen pulse (peak VO2/peak HR), 6) oxygen uptake efficiency (OUES), 7) carbon dioxide production efficiency (minute ventilation/carbon dioxide production slope), 8) CP (peak VO2 x peak systolic BP) and 9) VP (peak systolic BP/carbon dioxide production efficiency). Results: The CAD group had significantly lower values for peak VO2 (p < 0.001), peak HR (p < 0.001), peak systolic BP (p < 0.001), peak rate-pressure product (p < 0.001), peak oxygen pulse (p = 0.008), OUES (p < 0.001), CP (p < 0.001), and VP (p < 0.001) and significantly higher values for peak diastolic BP (p = 0.004) and carbon dioxide production efficiency (p < 0.001) compared with CG. Stepwise regression analysis showed that CP was influenced by group (R2 = 0.44, p < 0.001) and VP was influenced by both group and number of vessels with stenosis after treatment (interaction effects: R2 = 0.46, p < 0.001). Conclusion: The indices CP and VP were lower in men with CAD than healthy controls. .
Fundamento: Os índices da Potência Circulatória (PC) e Potência Ventilatória (PV) têm sido utilizados para avaliação clínica de pacientes com insuficiência cardíaca, mas nenhum estudo avaliou esses índices em pacientes com Doença Arterial Coronariana (DAC). Objetivo: Caracterizar ambos os índices em pacientes com DAC comparados a indivíduos saudáveis. Métodos: Oitenta e sete homens [grupo DAC = 42 sujeitos e, grupo controle (GC) = 45 sujeitos] com idade entre 45 e 65 anos foram incluídos. Um Teste de Exercício Cardiopulmonar (TECP) foi realizado em esteira e as seguintes variáveis foram obtidas: 1) consumo de oxigênio (VO2) pico; 2) Frequência Cardíaca (FC) pico; 3) Pressão Arterial (PA) pico; 4) duplo produto pico (PA sistólica pico x FC pico); 5) pulso de oxigênio pico (VO2 pico dividido pela FC pico); 6) eficiência ventilatória para o consumo de oxigênio (OUES); 7) eficiência ventilatória para a produção de dióxido de carbono (VE/VCO2 slope); 8) PC (VO2 pico x PA sistólica pico); e 9) PV (PA sistólica pico dividido pelo VE/VCO2 slope). Resultados: O grupo DAC apresentou valores significativamente menores das seguintes variáveis no pico do exercício: VO2 (p < 0,001), FC (p < 0,001), PA sistólica (p < 0,001), duplo produto (p < 0,001), pulso de oxigênio (p = 0,008), OUES (p < 0,001), PC (p < 0,001) e PV (p < 0,001), e valores significativamente maiores de PA diastólica (p = 0,004) e VE/VCO2 slope (p < 0,001) em relação ao GC. Uma análise de regressão pelo método stepwise mostrou que a PC foi influenciada pelo grupo (R2 = 0,44, p < 0,001) e a PV tanto pelo grupo quanto pelo número de vasos com estenose pós tratamento (efeito de interação: R2 = 0,46, p < 0,001). Conclusion: Os índices da PC e PV foram menores em homens com DAC comparados ao GC, podendo dessa forma ser utilizados na caracterização dessa população. .
Sujet(s)
Animaux , Humains , Oxyde d'aluminium/toxicité , Molécules d'adhérence cellulaire/métabolisme , Adhérence cellulaire/effets des médicaments et des substances chimiques , Endothélium vasculaire/effets des médicaments et des substances chimiques , Nanoparticules métalliques/toxicité , Cellules cultivées , Molécules d'adhérence cellulaire/génétique , Relation dose-effet des médicaments , Sélectine E/génétique , Sélectine E/métabolisme , Endothélium vasculaire/métabolisme , Endothélium vasculaire/ultrastructure , Expression des gènes/effets des médicaments et des substances chimiques , Molécule-1 d'adhérence intercellulaire/génétique , Molécule-1 d'adhérence intercellulaire/métabolisme , Microscopie électronique à transmission/méthodes , Monocytes/effets des médicaments et des substances chimiques , Monocytes/métabolisme , Monocytes/ultrastructure , Taille de particule , ARN messager/métabolisme , Suidae , Molécule-1 d'adhérence des cellules vasculaires/génétique , Molécule-1 d'adhérence des cellules vasculaires/métabolismeRÉSUMÉ
Background: Cetyl pyridinium chloride (CPC) liquefied sputum was shown to reduce AFB smear positivity presumably damaging cell wall of M. tuberculosis. Settings: National Institute for Research in Tuberculosis, Chennai, (Tamil Nadu). Objective: To assess the cell wall damage of mycobacteria in CPC liquefied sputum, by Transmission Electron Microscopy (TEM) and mycobacteriophage adsorption studies. Methods: Pooled sputum sample from smear positive pulmonary TB patients was homogenized and liquefied with CPC. It was examined in TEM daily for four days, to assess cell wall damage of M. tuberculosis, and photomicrographs were taken. M. smegmatis mc2155, treated with CPC, was infected with mycobacteriophage (phAE129) to study phage adsorption on cell wall and plaque formation. CPC untreated sputum and M. smegmatis formed controls. Results: Photomicrographs showed that cell wall of M. tuberculosis was intact in controls and damaged in CPC preserved sputum for 96 hours. Plaque formation was seen and absent respectively in CPC untreated and treated M. smegmatis cells. Conclusion: Exposure to CPC damaged the cell wall of M. tuberculosis within 96 hours. Mycobacteriophage failed to form plaques after M. smegmatis mc2155 was treated with CPC implying inhibition of phage adsorption on damaged cell wall and thus providing a clue for poor staining and smear positivity in microscopy.
Sujet(s)
Paroi cellulaire/composition chimique , Paroi cellulaire/physiologie , Cétylpyridinium/physiologie , Microscopie électronique à transmission/méthodes , Mycobactériophages/cytologie , Mycobactériophages/physiologie , Mycobacterium tuberculosis/cytologie , Mycobacterium tuberculosis/physiologieRÉSUMÉ
Trypanosoma brucei is a protozoan flagellate that causes African sleeping sickness. Flagellar function in this organism is critical for life cycle progression and pathogenesis, however the regulation of flagellar motility is not well understood. The flagellar axoneme produces a complex beat through the precisely coordinated firing of many proteins, including multiple dynein motors. These motors are found in the inner arm and outer arm complexes. We are studying one of the inner arm dynein motors in the T. brucei flagellum: dynein-f. RNAi knockdown of genes for two components of dynein-f: DNAH10, the a heavy chain, and IC138, an intermediate chain, cause severe motility defects including immotility. To determine if motility defects result from structural disruption of the axoneme, we used two different flagellar preparations to carefully examine axoneme structure in these strains using transmission electron microscopy (TEM). Our analysis showed that inner arm dynein size, axoneme structural integrity and fixed central pair orientation are not significantly different in either knockdown culture when compared to control cultures. These results support the idea that immotility in knockdowns affecting DNAH10 or IC138 results from loss of dynein-f function rather than from obvious structural defects in the axoneme.
Sujet(s)
Animaux , Axonème/métabolisme , Dynéines/composition chimique , Trypanosoma brucei brucei/métabolisme , Cycle cellulaire , Mouvement cellulaire , Dynéines/métabolisme , Flagelles/métabolisme , Modèles biologiques , Microscopie électronique à transmission/méthodes , Interférence par ARNRÉSUMÉ
Structural characteristics of discharged and undischarged nematocysts from the hydrozoans Millepora alcicornis and Millepora complanata, two fire corals collected in the Mexican Caribbean, were examined using transmission electron, scanning and light microscopy. In this study, we report for the first time images of the nematocysts found in these Mexican Caribbean venomous species. Two types of nematocysts were observed in both species, the more abundant identified as macrobasic mastigophore and the other a stenotele type. Macrobasic mastigophores were present in medium and large size classes while stenoteles appeared in only one size.
Sujet(s)
Animaux , Venins de cnidaires , Hydrozoa , Microscopie électronique à transmission/méthodesRÉSUMÉ
Biosynthesis of gold nanoparticles by Streptomycetes from Himalayan Mountain was undertaken for the first time. Out of 10 actinomycete strains tested, four strains (D10, HM10, ANS2 and MSU) showed evidence for the intracellular biosynthesis of gold nanoparticles, among which the strain HM10 showed high potency. Presence of spherical and rod shaped gold nanoparticles in mycelium of the strain HM10 was determined by transmission electron microscopy (TEM) and X-ray diffraction analysis. The average particle size ranged from 18-20 nm. UV spectral analysis indicated that the reduction of chloroauric acid (HAuCl4) occurred within 24 h of reaction period. Further, the strain HM10 showed enhanced growth at 1 and 10 mM concentration of HAuCl4. The gold nanoparticles synthesized by the strain HM10 showed good antibacterial activity against S. aureus and E. coli in well-diffusion method. The potential actinomycete HM10 strain was phenotypically characterized and identified as Streptomyces viridogens (HM10). Thus, actinomycete strain HM10 reported in this study is a newly added source for the biosynthesis of gold nanoparticles.
Sujet(s)
Actinobacteria/métabolisme , Antibactériens/biosynthèse , Antibactériens/composition chimique , Chlorures/composition chimique , Chlorures/métabolisme , Chlorures/pharmacologie , Escherichia coli/effets des médicaments et des substances chimiques , Composés de l'or/composition chimique , Composés de l'or/métabolisme , Composés de l'or/pharmacologie , Microscopie électronique à transmission/méthodes , Nanoparticules/composition chimique , Nanotechnologie/méthodes , Staphylococcus aureus/effets des médicaments et des substances chimiques , Streptomyces/métabolisme , Diffraction des rayons XRÉSUMÉ
The vesicourethral junction comprising the vesical trigone, is relevant in setting and positioning of the urinary bladder, along with the vesical neck, fixed by lateral ligaments of the bladder and tendinous arch of the pelvis fascia. Namely,the puboprostatic ligament (men) and the pubovesical (women). The circular set elastic fibers in this junction are important and valuable in the elasticity and plasticity of the area, allowing quick expansion and withdrawal with the flow of urine, and associated to smooth muscle tissue and nerve control form an important collective to maintain urinary continence. The objective of the present study is to describe the elastic system in the vesicouretral junction in relation to aging and its involvement in the states of urinary continence and incontinence, as well as the study of the vesicouretral junction in various age groups while evaluating with electron transmission microscopy. To carry out the study, 12 Wistar rats were used, divided into groups: neonate (4 animals), adult group (4 animals) and aged group (4 animals). Electron transmission microscopy with use of tanic acid technique associated to glutaraldehyde fixation, satisfactorily showed the extreme structural differences between mature elaunin and oxytalan fibers present between intercelular spaces and bundles of collagen fibers. The phases of elastogenesis in neonate animals and degradation of the elastic system of older animals were also evaluated.
La unión vesico-uretral, componente del trígono vesical, posee una relevante importancia en la fijación y posicionamiento de la vejiga urinaria conjuntamente con el cuello vesical, fijado por los ligamentos laterales de la vejiga y arco tendinoso de la fascia de la pelvis. Principalmente, sus componentes anteriores son: el ligamento puboprostático en los hombres y el ligamento pubovesical en las mujeres. Las fibras elásticas dispuestas circularmente en esta unión, son de valiosa importancia en la elasticidad y plasticidad de la región, permitiendo expansión y retiro rápido con el flujo de la orina, y asociado a musculatura lisa y control nervioso forman un conjunto importante para el mantenimiento de la continencia urinaria. Debido a existencia de puntos no esclarecidos en esta región en relación al sistema elástico y su participación en los estados de continencia/incontinencia urinaria, el presente trabajo tiene por objetivo el estudio de la unión vesico-uretral evaluándola en diferentes grupos etarios, a través de la microscopía electrónica de transmisión. Fueron utilizados 12 ratones Wistar, divididos en grupo de neonatos (4 animales), grupo adulto (4 animales) y grupo de ratones viejos (4 animales). La microscopía electrónica de transmisión, con uso de la técnica del ácido tánico asociado al fijador glutaraldeído, mostró satisfactoriamente las diferencias ultraestructurales entre las fibras elásticas maduras, elaunínicas y oxitalánicas, presentes entre los espacios intercelulares de las células musculares y haces de fibras colágenas, y también fases de elastogénesis en animales neonatos y envejecimiento y degradación del sistema elástico en los animales mayores.
Sujet(s)
Nouveau-né , Adulte , Sujet âgé , Rats , Urètre/anatomie et histologie , Urètre/chirurgie , Urètre/ultrastructure , Fibres musculaires squelettiques/anatomopathologie , Fibres musculaires squelettiques/ultrastructure , Microscopie électronique à transmission/méthodes , Tissu élastique/anatomie et histologie , Tissu élastique/physiologieRÉSUMÉ
This paper reports the natural poisoning by Sida carpinifolia (guanxuma, chá-da-índia) in cattle in Rio Grande do Sul, Brazil. Five cattle were affected in the period 2001-2008. Clinical signs included weight loss, incoordination, walking difficulty, generalized tremors, frequent falls, and death. Microscopically, the main changes were vacuolation of Purkinje neurons in the cerebellum, pancreatic acinar cells, and thyroid follicular cells. Transmission electron microscopy revealed vacuoles bordered by membrane containing finely granular material. Lectin histochemistry showed positive staining in neurons with the lectins Concanavalia ensiformis (Con-A), Triticum vulgaris (WGA), and Succinyl Triticum vulgaris (sWGA).
Relata-se a intoxicação natural por Sida carpinifolia (guanxuma, chá-da-índia) em bovinos no Rio Grande do Sul. Foram afetados cinco bovinos no período 2001-2008. O quadro clínico foi caracterizado por emagrecimento, incoordenação, dificuldade de locomoção, tremores generalizados, quedas frequentes e morte. Microscopicamente, as principais alterações foram vacuolização dos neurônios de Purkinje do cerebelo, das células acinares do pâncreas e das células foliculares da tireoide. A microscopia eletrônica evidenciou vacúolos com conteúdo finamente granulado e delimitado por membrana. Na lectina-histoquímica, observou-se marcação em neurônios com as lectinas Concanavalia ensiformis (Con-A), Triticum vulgaris (WGA) e Succinyl Triticum vulgaris (sWGA).
Sujet(s)
Animaux , Agglutinines germe blé/analyse , Malvaceae/effets indésirables , Malvaceae/intoxication , Malvaceae/toxicité , Végétaux toxiques/intoxication , Carcinome à cellules acineuses , Microscopie électronique à transmission/méthodes , Microscopie électronique à transmission/médecine vétérinaire , Cellules de Purkinje , Tumeurs de la thyroïdeRÉSUMÉ
El láser infrarrojo emitido por el diodo Arsenurio de Galio (904 nm) proporciona terapia a lesiones articulares por su acción analgésica, cicatrizante y antiinflamatoria, promoviendo a nivel celular síntesis de ATP mitocondrial, modulación de canales de calcio, activando el proceso mitótico e incremento en la síntesis de DNA y de proteínas. Para determinar las dosis que estimulen componentes celulares involucrados en síntesis proteica, del hígado de ratas fueron tomadas muestras de tejido normal e irradiado mediante láser infrarrojo con 1, 2, 4, 8 y 16 Joules/cm2 durante 15 días consecutivos. Fueron tratadas para microscopía electrónica de transmisión y se obtuvieron micrografías con aumentos de 10.000 X. Se realizaron estudios morfométricos, cuantificándose las fracciones volumétricas de núcleos, citoplasma, retículo endoplasmático rugoso (RER), inclusiones de glicógeno, nucleolos, eucromatina y heterocromatina, relación núcleo- citoplasmática y las áreas celulares y nucleares. Los resultados del presente estudio que compara hepatocitos normales e irradiados, indican que existen diferencias significativas en todos los parámetros evaluados. Se concluye que los hepatocitos estimulados alteran su morfología y por ende sus componentes celulares, modificando la función celular determinándose con exactitud la dosis de estimulación infrarroja donde estas células presentan un mayor desarrollo de su maquinaria citoplasmática involucrada en síntesis de proteínas.
The infrared lasser emitted by the Gallium Arsenide diode provides an adequate therapy for articular lessions due to their healing, analgesic, and anti-inflammatory powers. It also promotes at cellular level mitochondrial ATP synthesis, modulates Calcium channels and activate mitotic processes by increasing DNA and protein synthesis. To determine the effective doses which stimulates rat liver protein synthesis, several samples from normal and irradiated tissues to intensities of 1, 2, 4, 8, and 16 Joules/cm2 by 15 consecutive days were taken. These samples were later prepared and observed under transmission E.M. (10000X) and analyzed by morphometric studies, where volume and organelle distribution, such as nucleus, cytoplasm, endoplasmic reticulum, glycogen inclussions, nucleolus, eu and heterochromatin were accounted, together at nuclear-cytoplasmic relationships and the cellular and nuclear areas. Under comparison normal and irradiated hepatocytes presented a significative difference in all evaluated parameters. It can be concluded that at certain specific level of infrared irradiation, hepatocytes alter their morphology by modifyng those cellular components involved in protein síntesis.