The Bezold-Jarisch reflex. A historical perspective of cardiopulmonary reflexes.

The Bezold-Jarisch reflex is an eponym for a triad of responses (apnea, bradycardia, and hypotension) following intravenous injection of veratrum alkaloids in experimental animals. The observation was first reported in 1867 by von Bezold and Hirt, and confirmed in 1938-1940 by Jarisch. The triad depends on intact vagi and is mediated through cranial nervous medullary centers controlling respiration, heart rate, and vasomotor tone.

Cardiovascular disease and occupational exposure to environmental tobacco smoke.

Results of chemical analysis, animal experiments, and human studies are reviewed, criticized, and found not to support claims of an association between workers exposed to environmental tobacco smoke (ETS) and occupational coronary heart disease. This review also recommends refinement of the use of dose surrogates, as presently practiced by the Occupational Safety and Health Administration (OSHA), for regulating indoor emissions from combustion engines, coal furnaces, tobacco leaf processing, rayon viscose manufacturing, and rubber curing. The work standards OSHA uses for regulation of these complex mixtures could also be used in evaluating ETS and relate to the following constituents of ETS: nicotine, carbon monoxide, benzo[a]pyrene, and carbon disulfide.

Cervical ganglionectomy alters the circadian rhythm of intraocular pressure in New Zealand White rabbits.

A circadian rhythm of intraocular pressure in rabbits could provide a useful model for understanding the daily rhythm of intraocular pressure in humans and for studying mechanisms which regulate intraocular pressure. Our results confirm earlier work showing that New Zealand White rabbits housed in an environment with a lighting cycle of 12 hours light and 12 hours dark have a rhythm of intraocular pressure, and that this rhythm persists in constant dark. We show further that the cycle of light and dark is the zeitgeber for entrainment of the rhythm of intraocular pressure, and therefore persistence of this rhythm in constant dark establishes it as a circadian rhythm.

Pentoxifylline: a new drug for the treatment of intermittent claudication. Mechanism of action, pharmacokinetics, clinical efficacy and adverse effects.

During the past decade, the effectiveness of peripheral vasodilator drugs in the treatment of chronic occlusive arterial disease has been questioned. Pentoxifylline is a hemorheologic agent with primary actions that include increasing erythrocyte flexibility, reducing blood viscosity and increasing microcirculatory flow and tissue perfusion. The result is improved supply of oxygen to ischemic muscles of the limbs.

Pharmacology of pentoxifylline, a hemorheologic agent for the treatment of intermittent claudication.

Physiological and pathophysiological aspects of systemic and cardiac haemodynamics are reviewed with appraisal of Carl J. Wiggers merits and contributions to the research and developments in this field and his early recognition of the significance of the flow properties of blood in impaired circulation. Pharmacological agents involved in treatment of peripheral vascular diseases are discussed with special regard to the haemorheologically active xanthine derivative pentoxifylline.

Inosine : a naturally occurring cardiotonic agent.

For many years, Inosine was considered to be a simple metabolite of adenosine which was devoid of any cardiovascular effects. This theoretical ineffectiveness can be explained in the light of recent studies by the use of inadequate doses. In fact, higher doses of inosine, a non-toxic nucleoside, have demonstrated, experimentally, a cardiovascular activity and the pharmacological profile of this naturally occurring substance has been defined.

Peripheral vasodilators versus pentoxifylline for the treatment of intermittent claudication.

It should be recalled that the seven-center study conducted in the United States was initiated at a time when American physicians had recognized that past attempts to prove efficacy of peripheral vasodilators in treadmill testing had failed. The positive results derived from pentoxifylline treatment are significant because, for the first time, treadmill testing can prove the effectiveness of a hemorheologic drug, such as pentoxifylline, in the treatment of patients with intermittent claudication. Since treadmill testing is regarded as the most objective measurement of therapeutic success in claudicant patients, the positive results can assure us that hemorheologic drugs increasing erythrocyte flexibility are highly desired in treating peripheral vascular insufficiency, such as intermittent claudication.

Effects of fluorocarbons, chlorinated solvents, and inosine on the cardiopulmonary system.

The effects of fluorocarbons and chlorinated solvents on the cardiopulmonary system are reviewed. The new information, not hitherto reported, relates to the antagonistic action of inosine, a naturally occurring nucleoside formed in the body by deamination of adenosine. The effect of inosine on methylene chloride toxicity was investigated in open chest dogs anesthetized with pentobarbital sodium.

[Pharmacoloby of the bronchomotor tonus during anesthesia].

In a patient under general anesthesia, the occurrence of bronchospasm can be readily treated provided the cause is diagnosed early. The corrective drugs to dilate are readily available: atropine, epinephrine and theophylline. In the choice of preanesthetics, anesthetics and adjuvants, it is important to remember that there are differences in the bronchomotor effects; most curareform drugs constrict except pancuronium; most inhalational anesthetics dilate in contrast to intravenous anesthetics.

A comparative study between the cardiovascular effects of cetiedil, a new vasodilator, and papaverine and aminophylline.

The cardiovascular effects of progressively increasing infusions of papaverine hydrochloride, aminophylline and cetiedil, a new vasodilator, were studied and compared in the anesthetized intact dog preparations. Papaverine and aminophylline had qualitatively the same effects on the various parameters, but in general the maximal effects of papaverine were of a greater order of magnitude. Cetiedil exhibited a different pattern of cardiovascular activity characterized by initial decrease in mean pulmonary arterial flow of 16% accompanied by an increase in systemic vascular resistance of 28% and in pulmonary vascular resistance of 19%, a stage of restoration of mean pulmonary arterial flow to control level accompanied by decrease in dp/dt of 25% and increase in pulmonary vascular resistance of 27% and a final stage of decrease in mean pulmonary arterial flow, representing toxic effects and accompanied by decrease in mean aortic pressure of 26%, dp/dt of 54% and heart rate of 27%, and an increase in pulmonary vascular resistance of 84%.

Hemodynamic effects of aerosol propellants. III. Vascular resistance in the canine hind limb.

The question as to whether or not the hypotension observed as part of the effect of tricholorofluoromethane (FC11), dichlorofluoromethane (FC 12), dichlorotetrafluoroethane (FC 114) and methyl chloroform was due to a vasodepressor component of action, in addition to the previously documented depression in myocardial contractile force, was answered by testing these agents in an anesthetized dog preparation in which one hind limb was perfused at constant flow through the femoral artery. 5% FC 11, 20% FC 12 and 20% FC 114 decreased vascular resistance of the perfused limb, as reflected by decrease in mean femoral arterial perfusion pressure, in vagotomized but not in intact preparations. Methyl chloroform decreased vascular resistance even in intact preparations.