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T A Sims

Publications and source records attributed to T A Sims.

11 recordsLinked to original sources
PubMed1995

Host-parasite relationship between congenital Toxoplasma infection and mouse brain: role of small vessels.

Small vessels showing inflammatory cell infiltrates were invariably observed in the vicinity of intact Toxoplasma tissue cysts within the brains of mice congenitally infected with the protozoan. Lymphocytes were observed in intimate contact with the luminal aspect of the endothelium, penetrating into the thickened basal lamina and in the perivascular area, which also contained macrophages and neutrophilic granulocytes. Rarely, lymphocytes were observed attached to the outer membrane of the host neurone which contained a Toxoplasma tissue cyst and within the inflammatory infiltrate associated with a disintegrating cyst. An hypothesis is presented which combines these morphological observations to explain the events associated with tissue cyst associated recrudescence of latent Toxoplasma infection in mouse brain.

Animals↗
PubMed1990

Ultrastructural immunocytochemistry of the intact tissue cyst of Toxoplasma in the brains of mice with congenital toxoplasmosis.

Electron immunocytochemistry, using rabbit polyclonal anti-Toxoplasma IgG as the primary layer in immunogold staining, was used to assess the distribution of Toxoplasma antigen within, and in relation to, intact tissue cysts in brain tissue from mice with congenital toxoplasmosis. Toxoplasma antigen was widely distributed in the matrix of the cyst, being most concentrated in the proximity of the inner surface of the parasitophorous vacuole membrane (PVM). Relatively little Toxoplasma antigen was detected directly associated with cystozoites. Small amounts of antigen were detected within the host cell components exterior to the PVM and in the host neuropil immediately adjacent to the tissue cyst.

Animals↗
PubMed1989

An electron microscope and immunohistochemical study of the intracellular location of Toxoplasma tissue cysts within the brains of mice with congenital toxoplasmosis.

The wall of intact Toxoplasma tissue cysts within the brains of mice with congenital toxoplasmosis was investigated. Smaller cysts were identified within the soma of neurones. With larger cysts, the contained cystozoites were shown by ultrastructural examination to be surrounded by a layer of microtubules; immunohistochemical staining revealed that this layer contained neurofilament protein. Interior to this layer was a much convoluted parasitophorus vacuole membrane; exterior was the host cell membrane. In most cases, synaptic plates were noted on the outer plasma membrane. In no instance were tissue cysts observed either within neuroglial cells or in the absence of host cells. These observations are discussed in relation to the pathogenesis of congenital toxoplasmosis in the brain.

Animals↗
PubMed1988

Host-parasite relationship in the brains of mice with congenital toxoplasmosis.

The wall of intact tissue cysts in the brains of mice with congenital toxoplasmosis was investigated using light and electron microscopy. Impregnation of the wall with reduced silver salts and protargol silver suggested that it was composed, at least in part, of components derived from the neuronal cytoskeleton. Electron microscopy extended these observations and revealed that intact cysts were separated from the extracellular compartment by a layer of neurofibrillae enclosed within the host cell membrane. It is suggested that this may be a means whereby intact Toxoplasma tissue cysts are protected from the host's immune response.

Animals↗
PubMed1984

Stereological analysis of non-Hodgkins lymphomas.

A detailed stereological analysis was carried out on 30 lymph nodes at 2 ultrastructural levels. They were classified as follows: 10 were reactive lymph nodes, 10 were of low-grade non-Hodgkins lymphomas and 10 were of high-grade non-Hodgkins lymphomas. The mean and median values and interquartile ranges of nuclear profile diameter, nuclear volume, volume of cytoplasm, cell volume and absolute number of ribosomes were recorded for each case. The model proved very efficient in establishing several significant differences between the highgrade and lowgrade lymphomas and between the highgrade lymphomas and reactive lymph nodes but did not discriminate between lowgrade lymphomas and reactive nodes, nor did it distinguish neoplastic cells from reactive cells in the neoplastic group. The significance of these findings is discussed.

Humans↗
PubMed1981

The use of polystyrene microcarriers to prepare cell monolayers for transmission electron microscopy.

A simple method is described, using polystyrene microcarrier beads, that allows cell monolayers to be prepared without distortion for transmission electron microscopy. Cells cultured on polystyrene beads (Biosilon R, Nunc, Kamstrup, Denmark) are held in an agar matrix. Before embedding, the beads are dissolved in 1,2-epoxypropane. The technique increased the number of observable cells, when compared to preparations of planar monolayers, and there is good preservation of morphological detail.

Cell Line↗