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Biomedical subjects

C Johnson

Publications and source records attributed to C Johnson.

At least 505 records · Page 28Linked to original sources
PubMed1981

Plasma middle molecules in asymptomatic and "sick" uremic patients.

By using high speed gel filtration combined with ion exchange gradient elution chromatography, the concentrations of plasma (p) middle molecules (MM) were determined in 126 samples from 90 non-dialyzed azotemic patients and in 210 pre-dialysis samples from 53 regular hemodialysis and 24 intermittent peritoneal dialysis patients. Samples were taken, when the patients were free from major uremic symptoms (controls) and when they presented symptoms or signs of complication, i.e., intercurrent infection, edema, vomiting, pericarditis--in hemodialysis patients also malnutrition. Compared with the symptom-free controls, the patients with infection and malnutrition revealed higher p-MM fraction 7c. In patients with edema 7a and 7b were elevated. Vomiting was not associated with accumulation of MM. In non-dialyzed patients with symptoms, p-urea was higher than in the controls. No such difference was found in dialyzed patients. The p-creatinine concentrations did not differ between the groups studied. The results of this survey imply that uremic "sickness" is more often associated with high p-MM concentrations than with high urea or creatinine, whether the accumulation of MM is cause-effect related to uremic symptomatology or an epiphenomenon remains as an open question.

Chromatography, Gel↗
PubMed1980

Decreased motor activity of hyperactive children on dextroamphetamine during active gym program.

The motor activity of 10 hyperactive boys was measured during eight 1-hour active gym classes. Children received either dextroaomphetamine (0.5 mg/kg) or placebo elixir before each class, in a double-blind design. The program for each of the classes was participation in the active sports: hockey, basketball, and/or roller skating; the "task" throughout each hour was to play vigorously and continuously. The boys' mean hourly activity following amphetamine was slightly but significantly less than that following placebo. This finding is contradictory to the hypothesis that improved attention to an active task on stimulant would result in increased motor activity, and suggests the possibility of an independent direct effect of amphetamine on the motor system.

Attention↗
PubMed1980

Patellar malalignment: a treatment rationale.

A general review of present-day treatment for patellofermoral malalignment is presented. These regimens are viewed in light of known anatomical, biomechanical, and pathophysiological principles. We stress the need for a sound knowledge of biomechanical and pathophysiological principles prior to the initiation of surgical or rehabilitative techniques. Three major categories of surgery are discussed: 1) simple lateral release, 2) proximal "dynamic" realignment, and 3) distal patellar tendon realignment. A comprehensive rehabilitation program is presented based on sound biomechanical principles and known surgical techniques. We wish to stress the "non-surgical," conservative approach to patellofemoral malalignment through the use of a well-orgainzed and structured rehabilitation program.

Biomechanical Phenomena↗
PubMed1979

Trends in services for pregnant adolescents.

Because the rate of childbirth among adolescent girls in the United States is among the highest in the world, a pressing need exists for services for pregnant adolescents. After summarizing trends and indicating the complex problems in this area, the authors put forward recommendations for continued efforts.

Adolescent↗
PubMed1979

Severe right ventricular outflow tract obstruction caused by an intracavitary cardiac neurilemoma: succesful surgical removal and postoperative diagnosis.

A 32-year-old woman with a one-year history of progressive shortness of breath and chest pain was found to have a grade 4/6 systolic murmur at the base of the heart and left sternal border. Right ventricular enlargement was found by physical examination, ECG, and chest roentgenogram. Cardiac catheterization showed elevated right ventricular pressure, an intracavitary pressure gradient, and inability to enter the pulmonary artery. Angiography revealed a mass in the right ventricular outflow tract. Successful surgical removal of a large, well-encapsulated tumor mass was accomplished, and the tumor was interpreted as a benign neurilemoma. Postoperatively, the patient improved remarkably.

Adult↗
PubMed1979

Behaviour of human immunoregulatory cells in culture. I. Variables requiring consideration for clinical studies.

The suppressor function of lymphocytes stimulated with concanavalin A (Con A) provides a potential method for examining disorders of immunoregulation. Clinical application, however, requires definition of the culture conditions that influence the expression of normal suppressor cell activity. In the present studies culture conditions were modified until a sensitive assay for non-specific suppressor cell function was reproducible utilizing the response to varying doses of phytohaemagglutinin (PHA) as an indicator system. Practical conclusions included (1) that sensitivity was not lost if the suppressor cells and responder cells were allogenic; (2) that fresh responder cells were as sensitive as precultured responder cells; (3) that a wide range of Con A concentrations could induce suppressor activity; and (4) that the sensitivity of the assay was much enhanced by using suboptimal mitogen doses of PHA. Twelve percent of normal subjects gave false negative results but these could be avoided by studying cells at more than one time point after stimulation with Con A. Cells resting in culture for 7 days could be induced to suppress after stimulation with Con A and these suppressor cells were very sensitive to pharmacological doses of dexamethasone. Studies utilizing different times of cell pre-incubation before Con A stimulation and different periods of exposure to Con A revealed fluctuation in the induction of suppression that may represent alternating periods of suppression and amplifying activity among stimulated cells in vitro. Such variations will need to be taken into account in the application of this type of assay to clinical studies seeking disordered immunoregulation.

Cell Survival↗