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Biomedical subjects

W D Johnson

Publications and source records attributed to W D Johnson.

At least 235 records · Page 13Linked to original sources
PubMed1975

Inhibition of multiplication of Toxoplasma gondii by human monocytes exposed to T-lymphocyte products.

The multiplication of Toxoplasma gondii was quantitated in human monocytes in vitro by phase-contrast microscopy. Toxoplasma multiplication was identical in monocytes from subjects byt was significantly inhibited in cells from both sources if the monocytes were preincubated with immune lymphocytes and toxoplasma monocytes were preincubated with immune lymphocytes and toxoplasma antigen. Supernates prepared from toxoplasma-immune lymphocytes incubated with toxoplasma antigen were also effective in inducing in monocytes the capacity to inhibit toxoplasma multiplication. Supernative acitivty was evident after lymphocytes and antigen were incubated for as little as 15 min. The instruction of monocytes was also repid and reversible. Monocytes were fully induced to inhibit toxoplasma multiplication after a 2 h exposure to an active supernate, but they lost their inhibitory capacity on culture in vitro for 48 h in the absece of immune cells or their products. The lymphocytes particupating in the monocyte induction were identified as t cells. The in vitro stimulation of monocytes appeared to exhibit some specificity, since no inhibition of toxopreotein derivative and lymphocytes from tuberculin-positive subjects, concanavalin a-stimulated lymphocytes, or their supermates. Supernates which induced monocytes to inhibit toxoplasma multiplication did not influence parasite growth in HeLa cells.

Adult↗
PubMed1975

Reappearance of anterior QRS forces after coronary bypass surgery. An electrovectorcardiographic study.

This report describes the reappearance of anterior QRS electrical forces in six patients after direct coronary arterial bypass surgery. Each patient had severe coronary artery disease including a segmental stenosis of the left anterior descending artery. Revascularization was performed by direct anastomosis of the left mammary artery to the left anterior descending coronary artery and saphenous vein bypass of other stenotic coronary arteries. Preoperative electrocardiograms and vectorcardiograms showed patterns of anterior wall myocardial infarction with absent or diminutive anterior QRS forces. In each case, postoperative studies demonstrated the regeneration of anterior QRS forces within 10 days of operation. Although these patients represent a small percent of those with a preoperative pattern of infarction who undergo coronary revascularization, the findings demonstrate that electrically silent areas of myocardium may be altered and are not always synonymous with myocardial cell death. Chronic myocardial ischemia may in certain instances produce electrocardiographic and vectorcardiographic patterns of myocardial infarction that may be reversible upon reestablishment of perfusion to ischemic areas.

Adult↗
PubMed1975

Adult toxoplasmosis presenting as polymyositis and cerebellar ataxia.

A patient with toxoplasmosis had cerebellar, spinal cord, nerve root, and skeletal muscle symptoms. Toxoplasma gondii was isolated from skeletal muscle, and toxoplasma antibody titers were persistently elevated. The disease has been recurrent during a 3-year period with only temporary response to specific antimicrobial therapy.

Antigens↗