Biomedical subjects

J A Glenn

Publications and source records attributed to J A Glenn.

6 recordsLinked to original sources

PubMed2003

Can the effects of clinical reperfusion fluids on platelet aggregation in vitro predict the effects of administration of such fluids in a clinical study ex vivo?

Reperfusion fluids are administered routinely during surgical operations and following trauma. Studies performed wholly in vitro have indicated effects of some fluids on haemostasis through inhibition of platelet aggregation. Recently we performed a study to further evaluate the effects of reperfusion studies in vitro and also a study in a clinical setting to determine the extent to which the results of in vitro experiments can be extrapolated to the clinical situation. The results indicate that a combination of homeostatic and trauma response mechanisms complicate the ability to extrapolate from the findings in vitro.

Hemostasis↗

PubMed1995

Incident reports.

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Accidental Falls↗

PubMed1993

Histochemical evidence for microglia-like macrophages in the rat trigeminal ganglion.

Of the 4 major cell types in CNS parenchyma, microglia appear to serve the unique functional role of tissue macrophages. The distribution of equivalent cells in the PNS is unclear. Recently, the B4 isolectin of Griffonia simplicifolia was shown to bind selectively to microglia as well as to other macrophages under specific conditions. In the present study, this lectin was used to assess the existence of macrophages in the rat trigeminal ganglion. Vibratome sections of fixed ganglia were incubated with horseradish peroxidase (HRP)-conjugated isolectin, an HRP reaction subsequently performed, and sections processed for histology and viewed by light microscopy. Staining activity was found to be localised to a population of cells throughout the ganglion. These cells possessed small oval somata and several thin crenated processes, an appearance typical of ramified microglia. Stained cells also exhibited a regular, evenly spaced tissue distribution similar to CNS microglia. Finally, similar cells were also labelled by thiamine pyrophosphatase histochemistry, a cellular marker for CNS microglia/macrophages. It was concluded that there are microglia-like macrophages in the trigeminal ganglion and that these cells may function in immune reactions.

Animals↗

PubMed1992

Characterisation of ramified microglial cells: detailed morphology, morphological plasticity and proliferative capability.

Several cellular properties of brain microglia in the rat were investigated using both whole tissue and cultures of dissociated cerebral cortical cells. As revealed by thiamine pyrophosphatase histochemistry, tissue microglia possessed a highly distinctive cellular morphology. Stained microglia showed similar overall features of morphology and distribution in both preparations; however, the cells in culture displayed some slight differences from those of the tissue, including larger somata and less developed processes. Through studying living ramified cells in culture, both morphological plasticity as evidenced by patterned variations in soma size and mitotic activity were directly confirmed. It was concluded that ramified microglia definitely possess proliferative capability, and this may reduce the need for blood cell recruitment in brain immune responses. In addition, cultured microglia exist in a somewhat more activated state than those in normal tissue, and in some instances undergo further activation as macrophages. This cortical tissue culture system should provide an amenable preparation for investigating the regulation of microglial function.

Animals↗

PubMed1991

Pinocytotic activity in ramified microglia.

Pinocytotic activity was investigated in rat cerebral cortex using the soluble tracers horseradish peroxidase and Lucifer yellow. A subpopulation of cells selectively accumulated both compounds and the labelling was mainly present in pinocytotic vesicles associated with the cell body. Labelled cell bodies were small, round to oval, and distributed in an almost regular array throughout the tissue. Based on distinctive morphological features, some of the labelled cells could be determined as ramified microglia. This identification was confirmed by immunofluorescence staining with the monoclonal antibody OX-42, which specifically recognizes microglia; OX-42 staining consistently co-localized with pinocytotic labelling. The possibility that ramified microglial cells perform a normal function of continuous fluid exchange in brain tissue is discussed.

Animals↗

PubMed1989

Further studies on the identification of microglia in mixed brain cell cultures.

The investigation of brain microglia in primary cultures of dissociated cerebral cortical cells has been continued here utilizing a histochemical procedure for thiamine pyrophosphatase, which selectively stains microglia in whole tissue. This procedure also selectively stained a subpopulation of cells in the cortical cultures. The stained cells were small and exhibited quite variable morphology; from these features, a corresponding cell population could be identified in viable cultures. The stained cells, which were distinct from previously identified macrophage forms, were also distinguished from similar appearing cell types--small neurons and oligodendrocytes. Based on their staining properties, morphology, and distinction from other cell types, the identified cells are proposed as equivalents of ramified microglia.

Animals↗