Biomedical subjects

Steven Thompson

Publications and source records attributed to Steven Thompson.

4 recordsLinked to original sources

PubMed2006

Phospholipase D1 regulates phagocyte adhesion.

Adhesion is a fundamental cellular response that is essential to the physiologic processes of development, differentiation, proliferation, and motility, as well as to the pathology of inflammation, transformation, and metastasis. Adhesion of phagocytic leukocytes is a critical modulator of antimicrobial and cytotoxic functions, including the respiratory burst, secretion, and apoptosis. Because phospholipase D (PLD) is linked to several signaling pathways implicated in these processes, we tested the hypothesis that PLD regulates phagocyte adhesion. Adhesion of primary human neutrophils and monocyte-derived macrophages to fibronectin was accompanied by marked stimulation of PLD activity. Similarly, adhesion of both human (PLB, THP-1) and murine (RAW) myeloid-macrophage cell lines to fibronectin, fibrinogen, collagen, or plastic resulted in significant activation of PLD. Stimulation of PLD activity was rapid and persisted for at least 90 min. Confocal microscopy indicated that PLD1 exhibited partial colocalization with actin filaments at the adherent interface, in proximity to the focal adhesion protein, paxillin. Reductions in PLD activity by chemical inhibitors or specific short-interfering RNA-induced knockdown of PLD1 resulted in significant inhibition of phagocyte adhesion and was accompanied by reductions in total cellular F-actin. These data support the hypotheses that adhesion stimulates PLD activity, and that PLD1 regulates the initial stages of phagocyte adhesion. Stimulation of PLD activity may promote adhesion-dependent phagocyte effector responses.

Actins↗

PubMed2006

"Carry-on" dermal baggage: a nodule from a dog. Pyogranulomatous inflammation with intralesional fungal agents.

A 2-year-old intact female Australian Cattle Dog presented with a 1-cm diameter nonexudative dermal nodule on the medial aspect of the right thigh. Fine-needle aspiration revealed pyogranulomatous inflammation and many ovoid, 2-4 microm diameter, thin-capsulated, basophilic bodies that appeared to be fungal spores or yeast. Results of CBC, serum chemistry panel, lymph node palpation, and radiographs were unremarkable. Excisional biopsy and histopathology revealed pyogranulomatous folliculitis, furunculosis, and perifolliculitis. Rare fungal hyphae and spore forms were intimately associated with, and occasionally within, hair shafts. A morphologic diagnosis of dermatophytosis was made and Microsporum canis infection was confirmed by fungal culture. M canis is a common infectious agent found within the follicles and superficial keratin layers of canine skin. The kerion-type clinical presentation observed in the dog of this case is uncommonly observed with M canis. Additionally, the cytologic finding of multiple arthroconidia without hyphae is unusual. In the absence of hyphae, M canis arthroconidia may be confused with other fungal yeast bodies; therefore close scrutiny of a cytologic sample for arthroconidia associated with keratin, hair fragments, or hyphal structures is recommended.

Animals↗

PubMed2004

Effect of age on immune parameters and the immune response of dogs to vaccines: a cross-sectional study.

The evaluation of anti-aging intervention strategies in dogs would benefit from reliable quantitative biomarkers of aging. In the present study, the expression of various immune parameters was measured in young and old dogs to identify potential biomarkers of aging. The second goal of the study was to determine the effect of age on the immune response to vaccines. The immune function, including the antibody response to vaccines, was determined in 32 young adult (3.15+/-0.8 years of age) and 33 old dogs (12.1+/-1.3 years of age) of various breeds. Old dogs had a significantly lower lymphocyte proliferative response and a lower percentage of CD4+ T cells and CD45R+/CD4+ T cells, and a higher percentage of CD8+ T cells and a higher concentration of serum and salivary IgA. The most significant differences (P<0.001) occurred in the lymphocyte proliferative responses to ConA and PHA, the CD4:CD8 ratio, and the percentage of CD45R+/CD4+ T cells suggesting that these parameters are potential biomarkers of aging. There was no difference in the percentage of total T and B lymphocytes and the concentration of serum IgM and IgG. Both groups of dogs had protective titers against distemper virus, parvovirus and rabies virus before annual revaccination. The pre-vaccination titer against rabies virus was higher in the old dogs than in the young dogs, and there were no differences in post-vaccination titers against any of the viruses. This suggests that annual vaccination protocols provide adequate protection for old dogs.

Age Factors↗

PubMed2003

To relieve the sufferings of humanity, irrespective of party, politics or creed?: conflict, consensus and voluntary hospital provision in Edwardian South Wales.

This article examines the provision of voluntary hospital facilities for injured workers in the mining valleys of Edwardian South Wales. It considers the co-operation and conflict that characterized efforts to establish hospitals, and examines the attitudes and activities of workers, employers, and other interested groups. Despite certain instances of disagreement and conflict, this article demonstrates the significant levels of co-operation and consensus that characterized the efforts of employers and workers to provide communities with hospital facilities. This co-operation was perhaps surprising considering the bitter industrial conflict and social unrest of that period. The article uses this material to question assertions that hospitals reflect the social and political milieus of the communities in which they were situated and argues that the social relations produced by hospital provision sometimes coincided with wider social and industrial relations, but at other times differed from them or transcended them. Furthermore, the article demonstrates that the co-operation between employers and workers in the provision of hospitals in Edwardian South Wales did not stabilize social and industrial relations in the way that historians of associational voluntarism in other contexts have found.

Accidents, Occupational↗