Roth, Grace M.

When 24 normal subjects under basal conditions smoked two thirds of 2 cigarettes, there was no appreciable rise in the levels of the fasting blood sugar and the epinephrine-like substances of the systemic venous blood. However, the smoking of two thirds of 2 cigarettes significantly raised the blood pressure and pulse rate, and decreased the skin temperature of fingers and toes.

In normal subjects smoking or the injection of nicotine produces transient vascular effects on the heart and blood vessels. Apparently tobacco angina or tobacco heart is a clinical entity. Abnormal vascular responses after smoking in normal subjects may be due to hypersensitivity to nicotine, such as occurs in tobacco heart, or to the effect of nicotine on a vascular system demonstrated to be hyperreactive by the cold pressor test. Tobacco is one of the most prominent contributing factors in thromboangiitis obliterans, as thromboangiitis is rarely found in nonsmokers. The question as to whether the effects of smoking are due to sudden increased work of the heart or constriction of the coronary artery has stimulated a great amount of research. There is evidence to support both theories. The findings of abnormal ballistocardiograms before and after smoking in the offspring of hypertensive parents and after smoking in the offspring of parents with coronary heart disease are highly important. Statistically coronary artery disease seems to occur more frequently and at an earlier age in the person who smokes much than in the nonsmoker. Likewise, the mortality rate is higher among younger persons with coronary disease who are smokers than among those who are nonsmokers.

Various indirect methods of measuring blood flow in the peripheral blood vessels of man are available. Irrespective of the method used for measuring blood flow, certain fundamental factors concerned with the status of the subject or patient influence the measurement of blood flow. These factors are environmental temperature, position of the extremities and food. The present investigation indicates that a consideration of the basal metabolic rate or basal heat production is another important factor.

Intradermal injection of a fluorescent dye (riboflavin) and ultraviolet light were used to demonstrate cutaneous lymphatic capillaries. The extremities of a control group and the nonedematous extremities of patients with arteriosclerosis obliterans were studied together with edematous extremities of patients with lymphedema, acute thrombophlebitis, chronic venous insufficiency and various other conditions. The lymphatic capillaries showed up more extensively after a higher percentage of injections into edematous extremities of patients with lymphedema than after injections into the other extremities. On the other edematous extremities except in the cases of nephrotic syndrome and on the normal extremities, either no lymph capillaries or only a few were visible after most of the injections.

The response of the intra-arterial pressure to the cold immersion stimulus was studied in 42 healthy young adults, continuous direct (arterial-pressure) recording being used. The average systolic elevation was 22.6 mm. Hg and the average diastolic elevation was 16.3 mm. Hg. The difference between direct and indirect methods of measuring blood pressure was studied in 351 simultaneous determinations in 35 of these young adults. The direct systolic pressure averaged 9.7 mm. Hg higher and the diastolic pressure was 7.3 mm. Hg lower than the indirect measurement.

The cold pressor test was performed three times at 15-minute intervals on 65 normotensive subjects and on 60 patients with essential hypertension both before and during treatment with antihypertensive drugs. The arterial pressure was recorded directly from the radial artery. On the basis of differences in the cold pressor response among individuals in the control group, the criteria for normal reaction and for hyperreaction were modified. The cold pressor response in the patients with essential hypertension was markedly depressed by the ganglionic blocking agents, but was not affected by various combinations of hydralazine, protoveratrine and reserpine.

The effect of hexamethonium on hypertension has been widely studied but its effect on the peripheral blood vessels of patients with severe occlusive vascular disease has been studied on only a few patients although the drug has been used empirically in the treatment of such disease. Observations were made on the effect of hexamethonium ion administered subcutaneously in increasing doses of 10 to 50 mg. on the skin temperature of the fingers and toes, the blood pressure and the pulse rates of a group of patients with severe arteriosclerosis obliterans. On this group of patients hexamethonium had little or no effect.

Fluorescent quantitation of epinephrine and norepinephrine in plasma of patients suspected of having pheochromocytomas is of considerable diagnostic value. The concentrations of these pressor amines in normal subjects, patients with various diseases with and without hypertension, and 13 patients with pheochromocytomas are reported. In all patients with pheochromocytomas and sustained hypertension the concentrations of pressor amines were significantly elevated. However, in patients with paroxysmal hypertension secondary to pheochromocytomas the pressor amine concentrations may be unelevated when the blood pressures are normal. In this latter group provocative tests with intravenous histamine are indicated to induce hypertension prior to quantitating pressor amines.