Apicomplexans pulling the strings: manipulation of the host cell cytoskeleton dynamics

Invasive stages of apicomplexan parasites require a host cell to survive, proliferate and advance to the next life cycle stage. Once invasion is achieved, apicomplexans interact closely with the host cell cytoskeleton, but in many cases the different species have evolved distinct mechanisms and pathways to modulate the structural organization of cytoskeletal filaments. The host cell cytoskeleton is a complex network, largely, but not exclusively, composed of microtubules, actin microfilaments and intermediate filaments, all of which are modulated by associated proteins, and it is involved in diverse functions including maintenance of cell morphology and mechanical support, migration, signal transduction, nutrient uptake, membrane and organelle trafficking and cell division. The ability of apicomplexans to modulate the cytoskeleton to their own advantage is clearly beneficial. We here review different aspects of the interactions of apicomplexans with the three main cytoskeletal filament types, provide information on the currently known parasite effector proteins and respective host cell targets involved, and how these interactions modulate the host cell physiology. Some of these findings could provide novel targets that could be exploited for the development of preventive and/or therapeutic strategies.

The contribution of cellblock – histogel – in bronchial washing samples

Introduction: The cellblock is a technique that enables the pathologist to study the morphological detail of residual samples and can be used when it is necessary to perform additional diagnostic techniques. Objective: Demonstrate the processing of bronchial washings in liquid based cytology to cellblock using HistoGel in residual samples, evaluating the morphology and preservation of cytological material. Methods: There were used 40 residual samples from bronchial washings in liquid based cytology, after determination of the clinical diagnosis, being made subsequently 40 cellblocks using HistoGel. For each cellblock there was made one histological section for analysis of cell morphology, which was subsequently stained with the routine histological staining. After microscope observation, the morphology was evaluated by 3 experts in the field of pathology, based on the parameters: Cellularity, Preservation and Background. Results: The average final score of 3 evaluators, on a scale of 0 to 100, in assessing the morphology of the 40 samples was 55.6. From the 40 histological sections, 5 of them were considered not viable for evaluation. Conclusions: The results obtained indicate median quality maintenance of morphology. However, it is noted that in only 5 cases it was not possible to determine an evaluation, knowing from the outset that these are residual samples with a very scant cellularity. Thus, it is possible to say that the processing of bronchial washings to cellblock using HistoGel contributes to a concentration of the cytological material, allowing its evaluation and subsequent diagnosis. Additional diagnostic techniques are shown equally viable in these cellblocks.