29 research outputs found
Phylogenetic relationships among Toxocara spp. and Toxascaris sp. from different regions of the world
Toxocara and Toxascaris are parasitic nematodes that infect canids and felids although species of the genus
Toxocara also infect humans. This work aimed to establish the phylogenetic and phylogeographic relationship
between specimens of T. canis, T. cati, T. malaysiensis and Toxascaris leonina and to evaluate the degree of host
specificity. In total, 437 samples (adults and pools of eggs) were collected from canids and felids from eight
countries. Parasites were identified by morphology, PCR linked Restriction Fragment Length Polymorphism
(PCR-RFLP) and partial sequencing of the mitochondrial gene cox1. Phylogenetic trees were constructed and
genetic distance among isolates was estimated. Based on the molecular characterization all worms were identified in agreement with their respective hosts with the exception of three samples; two from cats and one from
dogs identified as T. canis and T. cati, respectively. There was no clear geographical clustering of the samples
despite this study including parasites from three continents. This is the first study, to our knowledge, to use
molecular methods to identify T. canis in cats and T. cati in dogs with host specificity being the most common
finding. Our developed PCR-RFLP method was found to be a facile and reliable method for identifying Toxocara
species.A91F-E8B8-FA62 | Teresa Susana Letra MateusN/
Sheddable Coatings for Long-Circulating Nanoparticles
Nanoparticles, such as liposomes, polymeric micelles, lipoplexes and polyplexes are frequently studied as targeted drug carrier systems. The ability of these particles to circulate in the bloodstream for a prolonged period of time is often a prerequisite for successful targeted delivery. To achieve this, hydrophilic ‘stealth’ polymers, such as poly(ethylene glycol) (PEG), are used as coating materials. Such polymers shield the particle surface and thereby reduce opsonization by blood proteins and uptake by macrophages of the mononuclear phagocyte system. Yet, after localizing in the pathological site, nanoparticles should deliver their contents in an efficient manner to achieve a sufficient therapeutic response. The polymer coating, however, may hinder drug release and target cell interaction and can therefore be an obstacle in the realization of the therapeutic response. Attempts have been made to enhance the therapeutic efficacy of sterically stabilized nanoparticles by means of shedding, i.e. a loss of the coating after arrival at the target site. Such an ‘unmasking’ process may facilitate drug release and/or target cell interaction processes. This review presents an overview of the literature regarding different shedding strategies that have been investigated for the preparation of sterically stabilized nanoparticulates. Detach mechanisms and stimuli that have been used are described