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Biomedical subjects

W Carson

Publications and source records attributed to W Carson.

At least 37 records · Page 2Linked to original sources
PubMed1993

Post-capillary Immobilon-P membrane fraction collection for capillary electrophoresis.

A simple, cost-effective and efficient method of continuous fraction collection for capillary electrophoresis is described. The method employs a membrane, such as polyvinylidene difluoride, onto which the separated components from a capillary electrophoresis capillary are directly collected to overcome the problem of analyte dilution and to facilitate the fraction collection process. Model proteins are separated and collected onto a polyvinylidene difluoride membrane.

Animals↗
PubMed1989

Vectorcardiograms in normal adult rats: with special reference to its pattern different from man.

To understand the vectorcardiographic (VCG) patterns in rats, we studied 50 adult male Long-Evans rats weighing 250-350g. Under anesthesia with pentothal, the rat was fixed to woodplate in a supine position with extremities extended. Surface electrocardiograms (ECG) and VCG of Frank lead system were then recorded in all rats. All variables of ECG and VCG were measured and compared with those of humans to determine the main difference. We found that rats have prominent anterior force of QRS complex and large ST vector in both ECG and VCG as compared to those of humans. The prominent anterior force of QRS complex may be due to different body shape between rat and human chests, and the large ST vector is probably related to early ventricular repolarization in rats. These findings should be considered in any experimental condition involving the ECG and VCG in rats.

Animals↗
PubMed1988

Maximal spatial ST vector of S-T segment elevation in the right praecordial leads on electrocardiogram due to acute pericarditis.

Three patients with acute pericarditis with S-T segment elevation in the right praecordial leads were studied by vectorcardiography. The vectorcardiographic findings suggested that, in acute pericarditis, the maximal spatial ST vector pointed to the left-anterior-inferior direction. The S-T segment elevations in the right praecordial leads in these patients were due to the large magnitude of the maximal spatial ST vector. Its magnitude indirectly caused S-T segment elevation in the right praecordial leads adjacent to it during the acute stage of pericarditis.

Acute Disease↗
PubMed1988

Vectorcardiographic criteria for acute right ventricular infarction.

Based on serial vectorcardiographic and cardiac scintigraphic studies of 62 patients with acute myocardial infarction, we propose vectorcardiographic criteria for the diagnosis of acute right ventricular infarction. These criteria are: (1) the direction of the maximal spatial ST vector points either to the right-anterior-inferior or to the right-posterior-inferior octant, and (2) the magnitude of the projection of the maximal spatial ST vector is greater than or equal to 0.15 mV in the horizontal plane. By using these criteria correlated with scintigraphic results, 92% sensitivity was achieved together with 98% specificity; the Kappa statistic was 0.90. In patients with acute inferior and right ventricular infarction, the serial maximal spatial ST vector swung to-and-fro like a 'tug of war' between right-anterior-inferior and right-posterior-inferior octants during the acute stage. In patients with acute inferior-posterior and right ventricular infarction, the serial maximal spatial ST vector pointed to the right-posterior-inferior octant during the whole course of the acute stage. Failure to recognize this electrical phenomenon may make the clinician inaccurate when judging the clinical course of acute right ventricular infarction or over-estimate the result of therapeutic intervention.

Adult↗
PubMed1988

Patterns of maximal spatial ST vector of S-T segment elevation in the right praecordial leads of the electrocardiogram in patients with acute inferior myocardial infarction.

Thirty patients with S-T segment elevation in the right praecordial leads during acute inferior myocardial infarction were studied by vectorcardiography. From the vectorcardiographic traces two types of maximal spatial ST vectors were seen. Their directions pointed either to: (1) the right-anterior-inferior, or (2) the right-posterior-inferior octant. This spatial ST vector could cause S-T segment elevation in the right praecordial leads in patients with acute inferior myocardial infarction in two ways. (1) The projection of the right-anterior-inferior maximal spatial ST vector on the horizontal plan pointing to right-anterior direction directly causes S-T segment elevation in the right praecordial leads--only a minority of patients (20%) show this. (2) The large magnitude of the right-posterior-inferior maximal spatial ST vector indirectly causes S-T segment elevation in the right praecordial leads adjacent to it. The majority of patients (80%) belong to this group. Therefore, the maximal S-T segment elevation in the electrocardiogram should be looked for in leads V5R to V8R. The direction of the vectors imply that in some patients there would be no S-T segment elevation in lead V4R. This study indicates that the use of S-T segment elevation in V4R, or several right praecordial leads, to claim that the maximal ST vector points to the right-anterior direction can be misleading. Without directional information, the use of single lead or several leads to detect the maximal spatial ST vector by a scalar electrocardiogram will give incomplete information.(ABSTRACT TRUNCATED AT 250 WORDS)

Bundle-Branch Block↗
PubMed1988

A modular spinal rod linkage system to provide rotational stability.

The effect of cross linkage on the in vitro stability of paired Harrington distraction rods was studied in an unstable fracture model using calf spine segments. Cross linkage used in conjunction with sublaminar wires significantly improved torsional stability, improved lateral bending stability, and had no adverse affect on stability for axial, forward flexion, or extension loading compared to rods alone, rods with bridges, and wired rods.

Equipment Design↗
PubMed1987

Human T-helper lymphocytes in myasthenia gravis recognize the nicotinic receptor alpha subunit.

Myasthenia gravis is a human disease caused by an autoimmune response against the nicotinic acetylcholine receptor (AcChoR). Since the molecular structure of AcChoR is well known, myasthenia gravis is an excellent system for studying the recognition of a complex membrane antigen in the human immune system. Human T-helper (TH) cell lines reactive to the AcChoR were isolated from four myasthenic patients by selection with native AcChoR from Torpedo californica. The selected TH cells could efficiently recognize native and fully denatured AcChoR. The vast majority of the TH-stimulating AcChoR epitopes were located on the denatured alpha subunit of AcChoR. Antibody competition experiments using a panel of rat anti-AcChoR monoclonal antibodies showed that 39-45% of the autoantibodies present in the sera of these same patients bound to the conformation-sensitive "main immunogenic region" (MIR), also located on the alpha subunit. However, AcChoR-induced stimulation of the T cells could not be inhibited with up to 20-fold molar excess of different rat anti-MIR monoclonal antibodies. These results suggest that the Torpedo AcChoR alpha subunit contains conformation-insensitive epitopes that play a role in the autosensitization of TH cells and that seem to be physically separated from the MIR. The specificity of the TH cell response may contribute to directing the B-cell response to other alpha-subunit determinants, such as the MIR itself.

Animals↗
PubMed1984

Vectorcardiographic features of acute right ventricular infarction.

A total of seven patients with acute inferior or inferior-posterior transmural myocardial infarction who had cardiac scintigraphically confirmed right ventricular (RV) involvement was studied. Series of vectorcardiographic tracings were taken using the Frank lead reference system from the second day after onset of acute symptoms; we found that in patients with acute inferior and RV infarction, the magnitude of the planar ST vector was greater than or equal to 0.15 mV and the projection of the ST vector pointed either to the right-anterior or right-posterior direction in the horizontal (H) plane. The serial spatial ST vector changed its direction either: 1) from right-anterior-inferior octant to right-posterior-inferior octant or vice versa; or 2) from right-posterior-inferior octant to right-anterior-superior octant. The larger the magnitude of the rightward ST vector, especially right-anterior direction in the H plane, the greater the probability of acute RV infarction. In patients with acute inferior-posterior and RV infarction, the magnitude of the ST vector in the H plane was greater than or equal to 0.2 mV. The spatial ST vector pointed to the right-posterior-inferior octant and its direction did not change from the original octant in the serial tracings during the course of the acute stage. Our data suggest that vectorcardiography--a non-invasive, non-nuclear polluting, and economical method--has shown great potential to become, in the near future, the primary non-invasive diagnostic test of choice for acute RV infarction.

Adult↗