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Biomedical subjects

M Bassan

Publications and source records attributed to M Bassan.

10 recordsLinked to original sources

Defining the proper role for self-administered sublingual nitroglycerin. A survey of physicians and patients.

Within a half-year period, we encountered six cases of patients harmed by the adverse effects of self-administered nitroglycerin--syncope, delayed definitive medical care, and the worsening of nonischemic symptoms. We therefore surveyed 112 patients after a remote myocardial infarction, and 121 cardiologists and internists, regarding the use of sublingual nitroglycerin. Of the physicians, 84 percent routinely prescribed nitroglycerin to patients after a myocardial infarction, and 79 percent of the patients had the tablets available (83 percent of these, at all times). Most patients used the tablets less than once per month, and 37 percent of the patients who always carried nitroglycerin had not used it at all during the preceding year. Although 89 percent of the patients claimed to know when to use the drug, 57 percent had used it or would use it for symptoms such as dizziness, rapid heartbeat, or presyncope. All patients having nitroglycerin claimed it relieved their symptoms, even if the relief was only partial, the time elapsed until relief could not be specified, and the symptoms were of a type unlikely to be relieved by the drug. We suggest that the practice of routinely prescribing nitroglycerin to patients after a myocardial infarction should be reassessed.

Administration, Sublingual

The day-long antianginal effectiveness of nitroglycerin patches. A double-blind study using dose-titration.

This study was designed to determine the day-long antianginal effectiveness of nitroglycerin patches in the nitrate-exposed patient, as well as the doses required. Eight men with chronic stable angina, a positive treadmill test, and demonstrated responsiveness to long-term oral isosorbide dinitrate were studied after they had been taking effective doses of isosorbide dinitrate three times a day for at least two weeks. Treadmill exercise bouts were performed every 1 to 2 hours over 1 day, after the 8 am application of active nitroglycerin patches in a previously titrated dose, and on another day after application of placebo patches. Mean necessary effective patch dose was 125 sq cm (60 to 220 sq cm). Mean exercise duration to angina rose from 271 to 480 s (p less than 0.001) 1 hour after active patches, while resting systolic blood pressure fell from 122 mm Hg to 100 mm Hg (p less than 0.001). (After placebo patches: +19 s and -2 mm Hg, respectively.) Active patches were superior to placebo throughout the day, but in declining degree (by 94 s at 7 pm, p less than 0.05). Thus, nitroglycerin patches can provide a significant day-long antianginal effect in the patient with long-term exposure to nitrate. However, the need for large doses and individual titration may make this therapy impractical.

Administration, Cutaneous

The effect upon coronary blood flow of coronary ostial intubation with an angiographic catheter.

Fifty-two patients undergoing cardiac catheterization were studied to determine whether intubation of the coronary ostium in the course of coronary angiographic studies interferes with coronary blood flow. Pressure at the tip of the catheter and coronary sinus blood flow were measured continuously during insertion of a No. 7.2 French Judkins' catheter into the left coronary ostium and during withdrawal of the catheter from it. In 48 of the 52 patients, there was no change in blood flow related to manipulation of the catheter. In four patients, either a drop in flow following insertion of the catheter or a rise following withdrawal or both were recorded. Two of these four patients had high-grade obstruction of the main left coronary artery, and in the other two the catheter inadvertently advanced and became wedged. In all four cases, reduction in coronary flow was indicated by a drop in or "ventricularization" of the catheter-tip pressure. It is concluded that in the large majority of instances, intubation of the coronary ostium during coronary angiographic studies causes no interference with resting coronary blood flow, but that monitoring of catheter-tip pressure is an important, as well as a valid, procedure for detecting such an interference if it should occur.

Cardiac Catheterization

The effect of intracoronary injection of contrast medium upon coronary blood flow.

The changes in coronary blood flow in response to intracoronary injection of 3 ml of 76% Renografin were studied in 47 patients using the thermodilution technique for continuous measurement of coronary sinus blood flow. Within seconds after left coronary injection, an increase in coronary sinus flow began which peaked at an average of 53% above control in 5-10 seconds. There was a corresponding decrease in coronary resistance. Flow returned to control level in almost all patients within one minute of injection. Twenty-four of 35 patients had no change in coronary sinus flow in response to right coronary injection. This can be explained by the fact that most of the venous flow from the right coronary artery returns in such a way that it cannot be measured by the coronary sinus catheter. Of the eleven patients who did show an increase, seven had angiographically documented right to left collaterals, suggesting that the increase in flow was the result of vasodilatation of the left coronary bed by contrast arriving via the right to left collaterals. The percent changes in flow and resistance in response to left coronary injection were isgnificantly greater in the 13 normals than in the 34 with obstructive disease of the left coronary artery (P lessthan 0.01). Flow rose 70 plus or minus 27% (mean plus or minus standard deviation) in the normals versus 46 plus or minus 25% in the patients with coronary artery disease, while resistance fell 44 plus or minus 9% versus 33 plus or minus 11%. The differences, however, were not sufficient for these changes to be of value in the assessment of the degree of impairment of the coronary arterial bed in the individual patient.

Blood Flow Velocity

Competitive binding assay for quantitative determination of GM1 ganglioside in plasma and cerebrospinal fluid.

A competitive binding assay for the quantitative determination of GM1 ganglioside is described. After extraction from biological fluids, GM1 was incubated with a known amount of cholera toxin B-subunit conjugated with horseradish peroxidase, and exposed to GM1 adsorbed onto polystyrene microwells. Since GM1 in solution blocks the binding of toxin B-subunit to GM1 adsorbed onto the solid phase, enzyme activity serves as a reciprocal measure of GM1 concentration in the sample. The assay was used to determine the basal level of GM1 in plasma and cerebrospinal fluid in different populations.

Adult