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Biomedical subjects

J Warren

Publications and source records attributed to J Warren.

At least 163 records · Page 9Linked to original sources
PubMed1978

Changing electrocardiographic recording technology and diagnostic accuracy of myocardial infarction criteria. Improved standards for evaluation of ECG measurement precision.

An analytical study was performed to estimate the magnitude of the visual Q wave duration bias produced by pressurized ink round stylus electrocardiographic (ECG) recorders. With a paper speed of 25 mm/sec and the ECG tracing width of 0.25 mm, the visually measured Q waves are on the average 8 msec too short. The corresponding error with the older type flat stylus recorder is less than 2 msec. Considerable differences can thus be anticipated in the frequency of observed ECG abnormalities in studies which use different types of electrocardiographs. The effect of the visual Q wave duration measurement bias on the diagnostic ECG classification was investigated in a group of 237 patients with old myocardial infarction and 299 subjects with no clinical evidence of infarction. An 8 msec measurement bias toward too short Q wave duration was observed to result in a potential loss of diagnostic accuracy of about 25% in some ECG coding categories. As a corrective procedure, it is recommended that the baseline width produced by a round recording stylus of uniform thickness irrespective of the vertical deflection velocity should be less.

Diagnosis, Computer-Assisted↗
PubMed1978

Systemic lupus erythematosus. Management during pregnancy.

The course of 27 pregnancies in 13 patients with systemic lupus erythematosus (SLE) is presented. The overall incidence of fetal wastage was 33.3%, a figure significantly higher than that observed in the general population. Although serum C3 complement levels rise during normal pregnancy, mean C3 levels remain within the normal range. Since it is a fall in complement levels in patients with SLE which may herald the onset of symptoms and provide a guide to therapy, assay of serum C3 complement levels remains a valid monitoring device in management of these patients during pregnancy. Flares of SLE during pregnancy generally should be treated vigorously with corticosteroids rather than by therapeutic abortion. Continuation of corticosteroid treatment during the first 2 months postpartum is advised to limit the incidence of exacerbation of SLE activity following delivery.

Antibodies, Antinuclear↗
PubMed1978

Oxygen immunosuppression: modification of experimental allergic encephalomyelitis in rodents.

Using protocols that incorporated double blind examination of animals sensitized to CNS antigen, we confirmed and amplified earlier findings of the complete suppression of EAE in rodents by hyperbaric oxygen. The effects of O2 were related to the gas pressure and duration of treatment. The development of paralytic disease was prevented for 34 days after sensitization (the longest interval studied). Compressed air or normobaric O2 administered under similar conditions did not modify the course of illness. Within 7 to 10 days after the discontinuance of oxygen therapy the majority of treated guinea pigs developed typical signs of EAE with characteristic lesions in the CNS. The relapses occurred sooner in the Lewis rat. The development of the delayed hypersensitivity reaction to myelin basic protein and to tuberculin is also suppressed by O2 therapy indicating that its effects upon autoimmune encephalomyelitis involves fundamental alterations of the cellular components of the immune response, some or all of which are reversible.

Animals↗
PubMed1977

Spatial summation effects on lingual vibrotactile thresholds.

Ascending lingual vibrotactile thresholds at 250 Hz were obtained for four groups of normal-speaking adult subjects. Contactor areas were varied for each respective group. Threshold values in microns plotted as a function of the area of vibratory displacement indicated a spatial summation function for the larger contactors (greater than .02 cm2). Findings are discussed in terms of the nature of lingual-tactile mechanoreception and possible implications for neural control mechanisms subserving speech production.

Action Potentials↗
PubMed1976

Lymphocyte surface-attached immunoglobulins in some clinical conditions.

The TEAG rosette test was not devised as an immediate diagnostic indicator, but in order to detect gross differences over a period of time between the lymphocytes of patients with conditions where immune complexes may be formed, and those of normal people. In summary these results indicate that:- 1. Percentage TEAG rosettes were highly significantly increased in patients with SLE, active chronic hepatitis and carcinoma of lung compared with normal controls, when the tests were performed on suspensions, containing over 90% lymphocytes, separated from peripheral blood. 2. Estimates of mean B lymphocytes plus blood monocytes in the separated suspensions, as measured by EAC rosettes (and peroxidase and differential counts for monocytes) are exceeded by TEAG-rosetting cells in the patients tested. 3. Tests on patients with chronic autoimmune conditions (e.g. ACH and SLE) do not show a highly significant difference from normal controls with respect to mean total cells forming E-rosettes. 4. It may be speculated that some TEAG rosettes are formed by T-cells which could have immune complexes or autologous anti-lymphocyte globulin on their surface and that such a condition may account for the depressed T-cell function found in these conditions.

Adult↗