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Biomedical subjects

J Holliday

Publications and source records attributed to J Holliday.

48 records · Page 3Linked to original sources
PubMedDate not supplied

Phorbol ester and Epstein-Barr virus dependent transformation of normal primary human skin epithelial cells.

Substantial evidence has implicated Epstein-Barr virus (EBV) in the aetiology of two human neoplasms, nasopharyngeal carcinoma (NPC) and Burkitt's lymphoma. This is supported by the presence of high antibody titres to EBV early antigen and virus capsid antigen, as well as antibody to two viral-associated enzymes, DNase and DNA polymerase. Patients with NPC, particularly the undifferentiated form, are commonly found to have EBV DNA in the tumour. Ito and others have presented strong epidemiological evidence that phorbol esters are related to the unusual geographic distribution of NPC in southeastern regions of China. There appears to be a close link between the widespread EBV infection of the Asian population and the distinct regional distribution in China of plants that produce diterpene ester. Naturally occurring phorbol esters are produced by plants of the Euphorbiaceae and Thymelaeaceae, which are used as traditional herbal medicines. Although it has been established that EBV can infect epithelial cells isolated from NPC as well as certain normal epithelial cells, there has been no in vitro evidence that EBV induces neoplastic transformation in normal human epithelial cells with or without exposure to phorbol esters. We report here evidence that transformation of normal human epithelial cells results from exposure to infectious EBV and that transformation is dependent on the presence of phorbol esters.

Carcinogens↗
PubMedDate not supplied

Psychosocial modifiers of immunocompetence in medical students.

This study addressed the effects of a naturally occurring stressor on components of the immune response. Blood was drawn twice from 75 first-year medical students, with a baseline sample taken one month before their final examinations and a stress sample drawn on the first day of final examinations. Median splits on scores from the Holmes--Rahe Social Readjustment Rating Scale and the UCLA Loneliness Scale produced a 2 X 2 X 2 repeated measures ANOVA when combined with the trials variable. Natural killer (NK) cell activity declined significantly from the first to the second sample. High scorers on stressful life events and loneliness had significantly lower levels of NK activity. Total plasma IgA increased significantly from the first to second sample, while plasma IgG and IgM, C-reactive protein, and salivary IgA did not change significantly.

Adult↗
PubMedDate not supplied

Mutagenic effect of mercury (II) in eukaryotic cells.

Acute exposure of KB and Chinese hamster ovary cells (AS52) to low concentrations of mercury (II) results in a dose dependent binding of mercury to DNA. This binding of mercury (II) to the DNA occurs at concentrations of mercury that have little if any effect on glutatione levels or on superoxide dismutase activity. Mutational studies with AS52 cells demonstrated that concentrations (0.1 to 0.4 microM) of mercury (II) which were not cytotoxic caused an increase (1.7 to 3.1) in the frequency of mutations in the gpt gene when compared to non-treated controls. These results suggest that there may be risks associated with exposure to non-cytotoxic levels of mercury (II).

Animals↗