ABSTRACT
Gold nanoparticle (AuNP) bioconjugates have been used as therapeutic and diagnostic tools; however, in vivo biocompatibility and cytotoxicity continue to be two fundamental issues. The effect of AuNPs (20 nm) conjugated with antibody [immunoglobulin G (IgG)], albumin, protein A, PEG4000, and citrate (cit) were evaluated in vitro using primary human cells of the vascular system. AuNP bioconjugates did not cause lysis of human erythrocytes, apoptosis or necrosis of human leukocytes, and endothelial cells in vitro, although AuNPs had been internalized and detected in the cytoplasm. Moreover, the influence of AuNPs on rheological parameters, blood and vessel wall characteristics was investigated in vivo by intravital microscopy assay using male Wistar rats mesentery microcirculation as model. Intravenous injection of AuNP-IgG or cit-AuNP did not cause hemorrhage, hemolysis or thrombus formation, instead suppressed the leukocyte adhesion to postcapillary vessel walls, an early stage of an inflammatory process. Furthermore, AuNP-IgG abrogated the expression of platelet-endothelial cell adhesion molecule-1, chemotaxis, and oxidative burst activation on neutrophils after leukotriene B4 stimulation, a membrane receptor-dependent stimulus, thus confirming their anti-inflammatory effects in vitro. The expression of oxidative burst activation was also suppressed after stimulating AuNP-IgG-treated neutrophils with lipid-soluble phorbol myristate acetate (PMA), confirming the direct intracellular action of AuNP-IgG on the inflammatory process in vitro. Our in vitro and in vivo experimental approaches highlighted the great potentiality of AuNP bioconjugates for therapeutic and diagnostic applications by parenteral routes.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/toxicity , Biocompatible Materials/toxicity , Endothelium, Vascular/drug effects , Gold/toxicity , Metal Nanoparticles/toxicity , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Apoptosis/drug effects , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Blood Flow Velocity/drug effects , Cell Survival/drug effects , Chemotaxis, Leukocyte/drug effects , Endothelium, Vascular/pathology , Erythrocytes/drug effects , Erythrocytes/metabolism , Erythrocytes/pathology , Gold/chemistry , Gold/pharmacology , Hemolysis/drug effects , Human Umbilical Vein Endothelial Cells , Humans , Immunoglobulin G/immunology , Leukocytes, Mononuclear/drug effects , Leukocytes, Mononuclear/metabolism , Leukocytes, Mononuclear/pathology , Male , Metal Nanoparticles/chemistry , Neutrophils/drug effects , Neutrophils/immunology , Particle Size , Rats, Wistar , Surface PropertiesABSTRACT
In the study of human hair, medulla is the less studied structure because it is believed that it has no influence on the fibre properties. The aim of this paper is to contribute to the better understanding of medulla morphology. Using reproducible methods for hair samples preparations allowed observing the inner fibre by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Three medulla subunits were observed in cryofractured samples. In addition, the application of plasma etching on samples allowed accessing chemical differences between them. Two kinds of medulla were identified using stereomicroscopy: thin and thick medulla. They were morphologically differentiated using TEM. These methods can be used to study systematically the effects of medulla on hair properties and to evaluate the efficiency of cosmetic products.
Subject(s)
Hair/ultrastructure , Cryoelectron Microscopy , Humans , Microscopy, Electron, Scanning , Microscopy, Electron, TransmissionABSTRACT
The remarkable occurrence of more than 4,500 conical siliceous mounds in an area of less than 1.5 square kilometres has been reported in the Paraná basin, near Anhembi, São Paulo, in southeastern Brazil. These structures, which are up to two metres high, are thought to have been formed at the margin of a very shallow, broad but waning internal sea, and it was originally suggested that they are stromatolites. Yet their restricted occurrence, unusual abundance and nearly pure siliceous composition have never been satisfactorily explained by this hypothesis. Here we report field and laboratory observations on their shape, construction, composition and mineralogy. On the basis of our data we suggest that the conical mounds are the result of subaqueous Late Permian vent activity in southwestern Gondwana. The present siliceous cone field differs considerably from other Palaeozoic siliceous hot spring deposits, such as those at Rhynie, Scotland, and the Drummond basin, Australia, and therefore represents an unusual occurrence of vent activity.
Subject(s)
Geologic Sediments/chemistry , Hot Springs/chemistry , Animals , Brazil , History, Ancient , Mollusca/chemistry , Oceans and Seas , Silicon/analysis , Silicon/chemistryABSTRACT
De há muito tempo, talvez mais de cem anos, fabricam-se instrumentos endodônticos especializados que pouco mudaram na sua morfologia ou na característica de uso. Um novo instrumento está sendo introduzido no mercado e a sua principal característica é a mudança da área de secção que segundo o fabricante não é mais quadrática e nem triangular. O presente trabalho visa mostrar, por meio de microscopia eletrônica de varredura, as alterações sofridas pelo uso sucessivo deste instrumento, o seu aspecto geral, e a sua capacidade de atuar no canal radicular
