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Biomedical subjects

J Johnson

Publications and source records attributed to J Johnson.

At least 631 records · Page 35Linked to original sources
PubMed1983

Effects of human T-cell subpopulations on B-cell proliferation as determined by (3H)-thymidine incorporation.

Human T-cell subgroups, fractionated by Fc receptor characteristics, have primarily been utilized to investigate their influence on B-cell immunoglobulin synthesis. We have investigated T subpopulation-B cell interaction by evaluating [3H]-thymidine incorporation of pokeweed mitogen-stimulated lymphocytes. DNA synthesis by B cells is dependent on T cells, but may be influenced by regulatory mechanisms that are distinct from those related to plasma cell differentiation. Peripheral blood mononuclear cells were divided into purified B cells, and three T-cell groups [T total (TI), T gamma (Fc receptors present for IgG), and T non-gamma (no Fc receptor on initial isolation)]. A fixed concentration of B cells (5 X 10(4) was then added to increasing concentrations of T gamma and irradiated TI or T non-gamma cells in the presence of PWM. The addition of irradiated T non-gamma enhanced [3H]-thymidine incorporation in a linear dose-dependent relationship. The addition of T gamma cells resulted in reduction in lymphocyte [3H]-thymidine incorporation is an alternative method for the evaluation of T-cell subgroup-dependent suppression or enhancement of human B-cell activity.

Antigens, Surface↗
PubMed1983

Coronary artery surgery and direct coronary artery thrombolysis during acute myocardial infarction.

Twelve patients underwent direct coronary artery streptokinase thrombolysis during acute evolving myocardial infarction. Ten patients had restoration of orthograde pulmonary blood flow. Eight patients had significant myocardial salvage and clinical stabilization. Nine patients had subsequent coronary artery bypass surgery with no major hematological or cardiac complications. Five of these had surgery performed immediately. Two patients with no myocardial salvage after streptokinase had urgent surgery because of other critical coronary lesions. Seven patients with thrombolytic salvage of myocardium underwent urgent coronary artery bypass surgery without incident. The occurrence of two reinfarctions in streptokinase-improved patients waiting for surgery suggests that delay is unwarranted and coronary bypass surgery is needed to insure success.

Arrhythmias, Cardiac↗
PubMed1983

Cerebral metabolic consequences of electrical cutaneous stimulation in normal individuals.

Local cerebral uptake of deoxyglucose labeled with fluorine (FDG) was measured by positron emission tomography in 21 normal adult controls. Seven subjects received FDG while resting in a dark room and fourteen while receiving unpleasant electrical stimulation of their right forearm in a dark room. All subjects showed greater glucose use in the anterior than in the posterior cerebral cortex. Electrical stimulation of the right forearm was associated with greater left than right glucose use in the region of the postcentral, but not precentral gyrus. The antero-posterior gradient in glucose use was increased at the level of the inferior frontal gyrus by the electrical stimulation. The data are consistent with the hyperfrontal pattern reported for regional cerebral blood flow and suggest that glucose use gradients across large brain areas are sensitive to sensory stimulation.

Adolescent↗
PubMed1983

Dietary saturated fatty acid content affects lymph lipoproteins: studies in the rat.

We examined effects on intestinal absorption of cholesterol and triglycerides and intestinal lipoprotein formation by feeding rats diets in which saturated fatty acids (palmitic plus stearic) comprised 78%, 68%, 48%, or 38% of triglyceride fatty acids. Absorption into lymph of radiolabeled cholesterol was proportional to triglyceride absorption. The rates of absorption of these lipids were related inversely to the % saturated fatty acids fed. The distribution of newly absorbed cholesterol and triglyceride into intestinal lipoproteins differed. With increasing cholesterol absorption more was recovered in very low density lipoproteins in contrast to the appearance preferentially in chylomicrons of larger quantities of fatty acid. Lymph lipid content did not reflect a consistent pattern in relation to the experimental diet fed. The fatty acid composition of triglyceride-rich lymph lipoproteins resembled the diet closely. One-quarter of the intestinal lymph particles from rats fed the highly saturated diets was flattened and polygonal as judged by electron microscopy if cooled to room temperature; whereas with the same diets, particles collected and isolated at 37 degrees C were round. Proportions of A-I and C apolipoproteins in triglyceride-rich intestinal particles varied inversely; apoA-I increased as fat/cholesterol absorption was greater. Diet-induced alterations in plasma lipoproteins and increased circulating triglycerides in this study in rats were unrelated to the variations in intestinal absorption or lymph lipoprotein formation.

Animals↗
PubMed1983

Computed axial tomography in ophthalmology.

Diagnostic accuracy of computed axial tomography (CT) of the eye and orbit is limited by resolving power and interpretation. Indiscriminate use of the scan is limited by radiation exposure and cost of the modality. The use of CT should be reserved in the ophthalmologist's supply of diagnostic modalities and be used as part of an orderly, logic scheme of diagnostic testing. The scheme proposed advises ordering a B-mode ultrasound before CT.

Adult↗
PubMed1982

A new system for gray-level surface distribution maps of electrical activity.

This report describes an integrated anatomical, electrophysiological and data management system for presenting cortical surface distribution maps. Approximately equal area projections (lateral and top) were constructed from a cross-sectional whole head atlas. Anatomical landmarks (major sulcus and gyrus locations) were also located on the outline. The outline and weights for interpolation are stored in the computer, with software for map generation directly from multilead EEG or evoked potential data. Electrode position and number can be easily varied and mapped onto any shaped space using the same program. Data derived from other sources such as xenon blood flow, brain scans or positron emission tomography can similarly be presented. The program uses a laboratory computer and emphasizes simplicity of data management and a mapping algorithm which is applicable to many forms of data.

Brain↗
PubMed1982

A prognostic index in primary breast cancer.

From a multiple-regression analysis of prognostic factors and survival in a series of 387 patients with primary breast cancer, a prognostic index has been constructed, based on lymph-node stage, tumour size and pathological grade. This index is more discriminating than lymph-node stage alone, and enables a larger group of patients to be identified with a very poor prognosis.

Adult↗
PubMed1982

Neonatal neurobehavioral effects of inhalation analgesia for vaginal delivery.

The authors studied the neonatal neurobehavioral effects of nitrous oxide:oxygen and enflurane:oxygen inhalation analgesia for vaginal delivery. Parturients were assigned randomly to receive no inhalation agent (Group 1, n = 21); enflurane, 0.3 to 0.8 per cent, and oxygen (Group 2, n = 22); or nitrous oxide, 30 to 50 per cent, and oxygen (Group 3, n = 18). Infants were tested at 15 min, 2 h, and 24 h of age using the Neurologic and Adaptive Capacity Score (NACS); and at 2 and 24 h using the Early Neonatal Neurobehavioral Scale (ENNS). No significant differences in neurobehavioral status occurred. For all groups, scores tended to be lowest at two hours of age. We conclude that neither enflurane nor nitrous oxide analgesia adversely affects neonatal neurobehavioral status at 15 min, 2 h, or 24 h of age.

Alphaprodine↗