PubMed HealthSearch

Biomedical subjects

S Mandel

Publications and source records attributed to S Mandel.

9 recordsLinked to original sources

Correlation analysis of somatosensory evoked potential waveforms.

Somatosensory evoked potential (SEP) waveforms were recorded over the spine and scalp in response to tibial nerve stimulation at the ankle for 28 subjects. The scalp data were analyzed with the correlation coefficient (CC) to determine the reproducibility of the signals and to identify side-to-side symmetry. The test for reproducibility uses the CC to verify validity, a low CC implying that the data are defective. The symmetry test uses the CC to obtain a measure of similarity of the responses to stimulation from opposite sides of the body. Statistics are presented showing the normal ranges of the CC values and their standard deviations. We conclude that the CC can provide objective and quantitative waveform information that complements latency and amplitude measurements in the clinical interpretation of tibial SEP waveforms.

Databases, Factual

Sympathetic dystrophies. Recognizing and managing a puzzling group of syndromes.

The sympathetic dystrophies are poorly understood and underdiagnosed, especially in their milder forms. Although the two major syndromes, causalgia and reflex sympathetic dystrophy, are similar in many aspects, significant differences remain in clinical presentation, pathogenesis, and management. This discussion of these syndromes focuses on clinical presentation and diagnosis for the primary care physician.

Adrenal Cortex Hormones

Indicator dilution measurement of 5-hydroxytryptamine clearance by human lung.

A double indicator dilution method to measure 5-hydroxytryptamine (5-HT) clearance by lungs of anesthetized patients is described. Immediately after a bolus injection of [3H]dextran and [14C]5-HT into the right atrial port of a Swan-Ganz catheter, blood from the radial artery is fractionated and the tritium and carbon-14 of each fraction is measured. The difference between the normalized curves of dextran and 5-HT vs. time reflect the extent to which 5-HT is extracted by the lung. This method gave a mean value of 61 +/- 3% (n = 10) for extraction of 5-HT, compared to 59 +/- 4% measured simultaneously by means of the pulmonary artery-left atrial gradient of 5-HT. Variations among three successive determinations in each patient made postoperatively were not statistically significant. This technique is applicable whenever Swan-Ganz and radial or brachial artery catheters are placed for routine clinical management and, therefore, may have wide application for measurement of pulmonary amine (or kinin) extraction in conscious human subjects or experimental animals. Because pulmonay clearance may be compromised by endothelial damage, 5-HT extraction measured in this manner could reflect early damage to human pulmonary endothelium--perhaps before clinical evidence of damage, such as interstitial edema and respiratory distress, is evident.

Carbon Radioisotopes

5-Hydroxytryptamine extraction by the lung.

Both 5-hydroxytryptamine and norepinephrine are removed from blood during a single passage through the pulmonary vasculature of the dog; 5-hydroxytryptamine is removed to a greater degree than is norepinephrine. The magnitude of extraction of both 5-hydroxytryptamine and norepinephrine is similar to that previously determined in man. In the intact dog, imipramine inhibits the uptake of 5-hydroxytryptamine by the lung in a dose-dependent manner.

Animals

Cardiopulmonary disease in Manson's schistosomiasis.

Five patients with cardiopulmonary manifestations of Manson's schistosomiasis are described. Two patients had pulmonary hypertension, two had cyanosis and one had the very rare combination of both. The results of routine pulmonary function tests--not sufficiently studied in this form of schistosomiasis--are discussed in detail. Aside from a tendency to hyperventilate, found in all cases, the only significant abnormality encountered was hypoxemia due to increased right-to-left shunt in the cyanotic patients. Although more studies are needed, the results suggest that the pulmonary lesions are mainly vascular in nature. The pathogenesis of cyanosis in this disease is briefly discussed.

Adolescent