Document NeKz3b9KdobaG5NKr0p75rqDy

Industrial Hygiene Digest April, 196o 353 Progress In Tetanus Prophylaxis: The Advent of Human Antitoxin. B. J. F. Percy. Can. Med. Assn. J. 94, 437-441 (Feb. 26, 1966). > Injections of tetanus antitoxin of animal origin frequently cause serious disability and some times death. Despite worldwide knowledge of these effects, millions of prophylactic injectio of equine tetanus antitoxin are gi'ven annually, and it is continually proposed that the dosage I Increased in order to obtain "higher protective" levels in the serum, a procedure which wool increase the incidence and severity of reactions. Furthermore, equine antitoxin frequently fails to prevent tetanus. Tetanus antitoxin of human origin is available which carries no risl of complications and confers a higher degree of immunity more quickly then equine antitoxin. The cost of treating reactions to horse serum, together with the financial loss incurred by work absence, far outweighs the <=oet of human antitoxin. In the author's opinion, the use in this country, (Canada) of antitoxin of animal origin is no longer medically acceptable and ma- well prove legally indefensible. There are 77 references. -- Author's abst. 354 Prevention of Allergic Immunlzati.on Reactions. J. Kawchak. J.Occ. Med. 8, 21*23 (Jan. 196 The procedure of administering opal chlorpheniramine permitted the author to immunize a large number of travelers to forei gn countries who had histories of allergy to substances in vaccines. On follow-up, none of tliese individuals demonstrated any evidence of allergic re action, The 8mg. repeat-action tablet is easily administered just prior to immunization, ant for most patients the antihlstamini.c activity of this one tablet last long enough so that no othe: administration is required. A review of 95 cases of patients with a history of sensitivity to allergenic substances showed that, with the aid of the prophylactic measure described, all we able to receive recommended imm.-unizatlons without untoward reactions either to the allergen in the vaccine or to the antihistamine. -- Author's conclusions 355 The Effects of Nitroglycerin and Azrayl Nitrite on Arteriolar and Venous Tone in the Human Forearm. D. T. Mason and E, Sraunwald. Circulation iZ, 755 (1965). In spite of the widespread use of nitroglycerin and amyl nitrite for relieving the pain of angim pectoris, considerable controversy* still surrounds the mechanism of action of these two drug! It has been proposed that they improve the relationship between coronary blood flow and the oxygen requirements of the heart b-y a direct dilating action on the coronary arteries, or that they diminish the oxygen requirements of the myocardium by diminishing the external work of the heart. Much of the confusion, concerning the actions of these drugs has arisen from the assumption that nitroglycerin and a-xnyl nitrite have similar effects. In order to determine whether the peripheral circulatory actions of nitroglycerin and amyl nitrite might play a role in their therapeutic effectB, the actions of these drugs on both the resistance and capacitance vessels of the forearm of normal huunan subjects were determined, and the results of these studies are described in this report. The authors emphasize that, since amyl nitrite and nitroglycerin have directionally oppo site effects on the venous bed, the efficacy of both of these drugs in angina pectoris can obviovasly not be explained by their effects on veins alone. In haled amyl nitrite results in a sudden and marked arteriolar dilatation, and it is probable that the coronary vessels participate in this Response. Ab a consequence of this arteriolar dila tation, systemic pressure declines markedly, thus also reducing myocardial oxygen require ments. It seems likely that the sahxtary dincial effects of this drug result from a combination of these two actions. -- Cond. from Can. Med. Assn. J. Absts. 35 6 Hemodynamic Effects of Nitroglvcer in in Patients With Coronary Heart Disease. B. Christensson, T. Karlefors, and H. Westling. Brit. Heart J. 27, 511 (1965). The hemodynamic effects of 0. Smg. nitroglycerin sublingually were determined at rest and during exercise on a bicycle ergome'Cer with the patient supine or sitting on the bicycle. Ar terial blood pressure, cardiac output: and oxygen consumption were measured. At rest the cardiac output and stroke volume decreased after nitroglycerin, A moderate tachycardia and a slight decrease in mean arterial pressure occurred. After nitroglycerin, exercise in the supine position was performed with a. lowered cardiac output and stroke volume and a higher calculated arteriovenous oxygen dlffe rence. These effects were more pronounced In the sit ting position. In the opinion of the authors, the results obtained give strong support to the view that nitroglycerin may relieve a-xglna pectoris by reducing the work of the heart. Some subjects studied were thus able to penrform an exercise which normally caused severe anginal pain, with a cardiac output that was mot much different from that at rest when they were free from pain. The reduction of cardiac output must mean that the exercise during nitroglycerin was performed with a high arterloveixaus oxygen difference. Nitroglycerin might thus be re garded as a drug that makes the circual&tory system more economical as regards flow and pressures. - Can. Med. Assn. J. Absts. 11 03122098