Biomedical subjects

A D Cook

Publications and source records attributed to A D Cook.

21 records · Page 2Linked to original sources

PubMed1993

Bacterial adhesion to protein-coated hydrogels.

Extended wear soft contact lenses have been implicated in the increased occurrence of corneal bacterial infections. This research investigated the effects of polymer chemistry, water content, and pre-sorbed proteins upon the adherence of Pseudomonas aeruginosa to model hydrogels with chemistries similar to those of extended wear soft contact lenses. The hydrogels were exposed to washed suspensions of P. aeruginosa in a laminar flow cell. Albumin, fibrinogen, desialylated fibrinogen, or mucin were deposited on the hydrogels before exposure to the bacteria. Results showed that with or without protein pre-exposure, bacterial adhesion decreased as water content increased. In the presence of the sorbed protein, the number of adherent bacteria increased by about 45%, and all four proteins caused similar increases in adhesion. Bacterial adhesion was not significantly influenced by the presence of sialic acid residues in the pre-sorbed protein.

Animals↗

PubMed1990

Distinction between 'inflammatory' and 'immune' macrophages killing Listeria monocytogenes in murine infection.

Two populations of efficiently phagocytic and bacteriolytic cells have been defined in the peritoneal cavity following infection of mice with Listeria monocytogenes. One was the result of a transient inflammatory response 2 days after intraperitoneal (i.p.) infection. It consisted of a mixture of monocyte/macrophages and neurotrophils which, when separated on Percoll gradients or by adherence, were both highly bacteriolytic compared with normal resident peritoneal macrophages. It was rich in recently divided cells as evidenced by in vivo labelling with tritiated thymidine. Although having the enlarged, vacuolated appearance of 'activated' macrophages, three-quarters of the monocyte/macrophages stained positive for myeloperoxidase (MPO), characteristic of monocytes rather than mature macrophages. In contrast, intravenous (i.v.) infection, which localizes in spleen and liver, did not produce this early response in the peritoneal cavity. However, 8 days after either i.v. or i.p. infection there existed in the peritoneal cavity a highly active population of cells comprising chiefly macrophages of typical foamy appearance which did not stain for MPO+. They were actively phagocytic and bacteriolytic and, like the early inflammatory exudate, produced increased amounts of oxygen degradative products. They appear to typify the concept of macrophages activated by T cell mediated immunity. Two day peritoneal exudates induced in these previously infected mice by i.p. rechallenge with L. monocytogenes organisms comprised mostly MPO- macrophages.

Animals↗

PubMed1975

Vanillyl mandelic acid excretion in unilateral electroconvulsive therapy (ECT).

The twenty-four hour urinary excretion of vanillyl mandelic acid was determined in a group of eleven psychiatric patients prior to and during the day of the fifth unilateral electroconvulsive treatment. The patients were all determined by their treating psychiatrists and by psychological testing to be psychotically depressed. In ten of the eleven patients a marked decrease in excreted vanillyl mandelic acid was apparent from the pretreatment level to the fifth treatment level. In one of the eleven patients there was a slight rise from the pretreatment level to the excreted level during the fifth day of treatment. The mean pretreatment determination of vanillyl mandelic acid was 4.2 mg per twenty-four hours; the mean determination made on the fifth treatment was 2.8 mg per twenty-four hours.

Depression↗