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Biomedical subjects

W S Harris

Publications and source records attributed to W S Harris.

At least 109 records · Page 6Linked to original sources
PubMed1971

Ventricular arrhythmias induced in monkeys by the inhalation of aerosol propellants.

After inhaling fluoroalkane gases, which are used as aerosol propellants, some people have died suddently and unexpectedly. Seeking an explanation, we had 14 monkeys inhale these gases. All developed ventricular premature beats, bigeminy, or tachycardia, which began at an average of 39 (SE +/-4.2) sec. Fluoroalkanes were present in blood, but arterial hypoxemia or hypercapnia was absent, and arterial pressure was reduced only slightly. In contrast, without fluoroalkanes, 3 min of asphyxia or anoxia caused arrhythmias in only one monkey whose arterial oxygen tension had fallen to 16 mm Hg. The ventricular arrhythmias caused in well oxygenated monkeys by fluoroalkane gases may either be mediated through beta adrenergic receptors, since propranolol abolished these arrhythmias, or result from a nonadrenergic, direct, toxic effect of these gases on the heart. These results suggest that some deaths after propellant inhalation may be caused by ventricular tachycardia or fibrillation.

Aerosols↗
PubMed1970

Glue sniffing causes heart block in mice.

In mice, the inhalation of airplane glue or toluene fumes slows the sinoatrial rate, prolongs the P-R interval, and sensitizes the heart to asphyxia-induced atrioventricular block. In humans who sniff glue or solvents, similar mechanisms may be a cause of sudden death.

Animals↗
PubMed1967

Effects of adrenergic receptor activation and blockade on the systolic preejection period, heart rate, and arterial pressure in man.

We have investigated the possibility that alterations in the duration of the systolic preejection period can be used to estimate adrenergic influences on the human left ventricle. The preejection period was determined from high speed, simultaneous recordings of the phonocardiogram, carotid pulse tracing, and electrocardiogram. The preejection period was shortened by isoproterenol, epinephrine, and moderate doses of norepinephrine-all of which activate beta adrenergic receptors-and by cedilanid-D. It was unaltered by changes in heart rate induced by atropine and right atrial electrical pacing. Beta adrenergic receptor blockade by propranolol abolished the shortening effects of the three catecholamines but did not inhibit that due to cedilanid-D. Vasoconstriction, both alpha adrenergic (epinephrine and norepinephrine after propranolol) and nonadrenergic (angiotensin), prolonged the preejection period. Most of the shortening of the preejection period by beta adrenergic receptor activating agents and cedilanid-D and all of the prolongation accompanying pharmacologic vasoconstriction occurred after the onset of the first heart sound, thereby excluding changes in electrical-mechanical delay as a major factor in the observed preejection period responses. Shortening of the preejection period by beta adrenergic activity induced with isoproterenol was dose-related. Increasing doses of propranolol produced parallel shifts to the right in the isoproterenol dose-response curve. In 37 normal resting subjects intravenous propranolol (10 mg) prolonged the preejection period an average of 10 (SE +/- 1) msec. In six patients with psychogenic sinus tachycardia and a patient with a pheochromocytoma the presence of excessive beta adrenergic influences on the left ventricle was demonstrated by the finding of an initially short preejection period which responded with an abnormally great prolongation to beta adrenergic receptor blockade.

Adult↗
PubMedDate not supplied

Inhibition of low density lipoprotein synthesis by dietary omega-3 fatty acids in humans.

Diets rich in omega-3 fatty acids derived from fish oils lower the plasma concentrations of low density lipoproteins (LDL) and very low density lipoproteins in humans. The present study was designed to examine the mechanism(s) by which diets enriched in omega-3 fatty acids reduce plasma LDL cholesterol levels in normal subjects. Seven healthy volunteers with normal plasma lipid levels consumed two metabolically controlled diets for a period of 4 weeks each. The control diet contained predominantly saturated and monounsaturated fatty acids, whereas the fish-oil diet contained 24 gm of omega-3 fatty acids per day. The total fat and cholesterol content of the two diets were similar for each subject. Total and LDL cholesterol levels decreased from 162 +/- 26 mg/dl and 103 +/- 27 mg/dl on the control diet to 124 +/- 26 mg/dl and 82 +/- 27 mg/dl on the omega-3-rich diet. Triglyceride levels fell from 91 +/- 34 mg/dl to 52 +/- 19 mg/dl. Kinetic studies of 125I-LDL metabolism disclosed a significantly lower rate of synthesis of LDL apoprotein B on the omega-3-rich diet (9.5 +/- 1.3 mg/kg/day) as compared to the control diet (13.6 +/- 3.7 mg/kg/day; p less than 0.05). In contrast, the fractional catabolic rate was similar on both diets. We conclude that dietary omega-3 fatty acids lower plasma LDL levels in normal human subjects by reducing the rate of synthesis of apoprotein B.

Adult↗
PubMedDate not supplied

Identification and characteristic of LDL-subfractions in human plasma.

Density gradient ultracentrifugation and high resolution polyacrylamide gel electrophoresis (Lipoprint LDL-system) were used to examine the discrete LDL subfraction patterns in normal and hyperlipidemic patients. Two new programs for LDL and VLDL subfractions were elaborated and a new method of evaluation for cholesterol content in LDL-subfractions, based on area distribution ratio of densitograms without density gradient ultracentrifugation, was created. The predominance of cholesterol and triglycerides in dense LDL3-subclass (d-1,048-1,063 g/ml) under hypercholesterolemia and hypertriglyceridemia was found. Lipoprint LDL-electrophoresis method was developed for the characteristic of lipemic state of organism and detection and quantitation of plasma LDL subfractions.

Electrophoresis, Polyacrylamide Gel↗