Myocardial perfusion and left ventricular performance during exercise-induced ST-segment depression in apparently healthy subjects

Ischemic-like ST-segment depression seen during exercise in apparently healthy subjects has previously been noted, but the cause of this change is unknown. The aim of this study was to investigate the pathophysiology of this electrocardiographic change. Ten healthy subjects who developed an electrocardiographic "ischemic" pattern of ST change during treadmill exercise testing were studied. All subjects underwent both thallium-201 myocardial perfusion imaging and radionuclide angiocardiography at rest and during exercise at a time when abnormal ST changes appeared, and demonstrated a normal homogeneous pattern of thallium-201 distribution on both rest and exercise images. Overall, left ventricular ejection fraction rose from 0.60 +/- 0.06 (mean +/- SD) at rest to 0.65 +/- 0.07 with exercise. None of the subjects had regional wall motion abnormalities at rest or during exercise. These results are different from the findings observed in patients with coronary heart disease and angina pectoris in whom regional abnormalities in both perfusion and left ventricular performance have been noted during exercise. Therefore it would seem that myocardial ischemia is not likely to be a tenable explanation for the electrocardiographic "ischemic" changes in these apparently healthy subjects.

Effect of low dosage of interferon on natural killer activity in patients with HBsAg-positive chronic active hepatitis

The effect of human leukocyte interferon (IFN) on natural killer (NK) activity in 7 patients with HBsAg-positive chronic active hepatitis was investigated. Human leukocyte IFN was intramuscularly given once a week for 4 consecutive weeks (10 X 10(5), 5 X 10(5), 2 X 10(5) and 1 X 10(5) U). 1 week after the initial injection, NK activity showed a significant rise compared with the preinjection levels (p less than 0.001) and remained elevated during the 1-month treatment, while it fell after the cessation of IFN therapy. 4 of 5 patients showed a marked decrease in Dane particle-associated DNA-polymerase activity. Serum HBeAg disappeared in 3 of 6 patients and serum transaminase levels markedly improved in all patients. Only a transient reduction in HBsAg was observed in 2 patients after the treatment period. The findings indicate that a low dosage of human leukocyte IFN such as 18 X 10(5) U, administered in decreasing doses, enhances NK activity in patients with HBsAg-positive chronic active hepatitis, and that the effect of IFN is involved in the immune mechanisms associated with natural cytotoxicity.

Determination of anaerobic threshold for assessment of functional state in patients with chronic heart failure

The use of anaerobic threshold in assessment of aerobic capacity was evaluated in 34 normal subjects and 47 patients with various kinds of chronic heart disease. Anaerobic threshold was determined as the oxygen consumption (VO2) at which a linear relationship between pulmonary ventilation (VE) and VO2 was lost during progressive treadmill exercise. Anaerobic threshold determined in this manner was validated with that determined by blood lactate measurements in eight normal subjects and nine cardiac patients (r = .962, p less than .001). Thereafter, anaerobic threshold was determined only by respiratory measurements. In symptom-limited, maximal exercise, anaerobic threshold was reached well before maximal effort and corresponded to 70% of maximal VO2 both in normal subjects and cardiac patients. Anaerobic threshold decreased as age progressed in normal subjects (r = - .70, p less than .001). Anaerobic threshold in cardiac patients was lower than that in the normal subjects and decreased progressively as New York Heart Association functional classification advanced (normal, 32.95 +/- 6.17 ml/min/kg; class I, 22.78 +/- 3.74; class II, 16.99 +/- 3.66; class III, 12.97 +/- 2.76; p less than .01 between each group other than between class II and class III). Anaerobic threshold in cardiac patients correlated poorly with other objective indices, e.g., cardiomegaly (r = -.54, p less than .001) and rise in pulmonary wedge pressure (r = -.64, p less than .001). At anaerobic threshold, cardiac patients subjectively graded the work load as light (13%), light-to-moderate (27%), moderate (30%), and moderate-to-heavy (28%). Thus determination of anaerobic threshold by respiratory measurements is a safe, accurate, and objective method to measure aerobic capacity in cardiac patients and in normal subjects.

Plasma norepinephrine concentration and plasma dopamine-beta-hydroxylase activity in patients with congestive heart failure

The relationship between plasma norepinephrine (NE), epinephrine (E) and dopamine-beta-hydroxylase activity (DBH) was studied in 90 cardiac patients (New York Heart Association [NYHA] classes I-IV), 85 healthy control subjects and 18 competitive skiers. The cardiac patients in NYHA classes III and IV had significantly higher NE (p less than 0.001) and lower DBH (p less than 0.001) levels than the controls, whereas the skiers had significantly lower NE (p less than 0.001) and higher DBH (p less than 0.05) levels than the controls. Seven cardiac patients in whom successful cardiac surgery was performed had decreased NE (p less than 0.001) and increased DBH (p less than 0.02), as well as significantly improved NYHA cardiac status (p less than 0.001). These findings demonstrate an inverse relationship between NE and DBH in a population of athletes, normal subjects and cardiac patients; the same inverse relationship holds for these patients when sequential studies are done after a change in cardiac status.

Therapeutic effect of a low dosage of human leukocyte interferon on chronic hepatitis B virus infection

A low dosage of human leukocyte interferon was intramuscularly given to 47 patients with hepatitis B surface antigen (HBsAg) positive chronic active hepatitis once a week for 4 consecutive weeks (10 X 10(5), 5 X 10(5), 2 X 10(5) and 1 X 10(5) U). After treatment, a reduction of serum HBsAg was observed in 26 patients; 3 of them showed no serum HBsAg and 1 of the 3 appeared to produce antibody to HBsAg. 31 of 34 patients investigated showed a significant decrease in Dane particle-associated DNA-polymerase activity (p less than 0.001). Among 17 patients positive for hepatitis B e antigen (HBeAg), 10 of them seroconverted to anti-HBe. Serum transaminase levels also significantly improved in 34 of 38 patients (p less than 0.001). Our findings indicate that a low dosage of human leukocyte interferon such as 18 X 10(5) U, administered in progressively decreasing doses, may be effective in the treatment of chronic hepatitis B virus infection.

Conditions for "coronary steal" caused by coronary vasodilator in man

This study was undertaken to assess the conditions necessary to cause the "coronary steal" phenomenon in human subjects. We studied 42 patients (36 males, 6 females, ages 27--70 years) with known or suspected coronary artery diseases using continuous monitoring of the changes in blood pressure and electrocardiogram, thallium-201 myocardial imaging and selective coronary arteriography. Dipyridamole in a dose of 0.4 mg/Kg was given as an intravenous infusion for 4 min and thallium-201 was injected at the 4th minute after completion of the dipyridamole infusion. None of the 20 patients without significant coronary artery disease complained of anginal chest pain or showed ischemic S-T segment depression. Dipyridamole images showed no perfusion abnormalities in 17 of the 20 patients. On the other hand, in 4 of the 22 patients with significant coronary artery disease, anginal chest pain accompanied with S-T segment depression occurred after the dipyridamole infusion. Dipyridamole images showed perfusion abnormalities in 18 of the 22 patients. The 4 patients who experienced an anginal attack had 3 vessel disease on the coronary arteriogram and showed regional perfusion defects on scintigrams corresponding to the regions receiving collaterals. Before the onset of pain, the double product (heart rate X systolic arterial pressure) was unchanged significantly but there was a reduction in the systemic blood pressure. The overall data exhibit the following conditions under which attacks of angina pectoris are induced by dipyridamole: 1) the presence of multiple vessel disease, 2) a fall in systemic blood pressure, and 3) regional malperfusion caused by dipyridamole.

Effect of a streptococcal preparation on the complement system

Streptococcal preparation OK-432 (Picibanil), clinically being used as an immunopotentiator, has been shown to activate the complement system either through the classical or the alternative pathway in vitro [15]. In this experiment, OK-432 was found to increase serum complement level in guinea pigs, and in human without malignancy, when investigated by hemolytic assay using sensitized sheep erythrocytes (EA) for the classical pathway activity and unsensitized rabbit erythrocytes (RaE) for the alternative pathway activity. Assay of complement components revealed a significant increase in C3, but decrease in Clq, while no specific tendency was observed in C4, C5, C9, properdin, C3 activator and Cl-inhibitor. These evidences suggested that OK-432 might potentiate immune response of the host by elevating serum complement level, in addition to activate the complement system.

Lipid peroxidation and lysosomal enzymes in D-galactosamine hepatitis and its protection by vitamin E

Role of lipid peroxidation on lysosomal instability in liver tissue was investiaged in an experimental model of D-galactosamine hepatitis in rats fed on vitamin E (V.E) deficient diet. Administration of D-galactisamine to V.E deficient rats resulted in a sudden increase of serum glutamic oxaloacetic transaminase (sGOT), glutamic pyruvic transaminase (sGPT), lipid peroxide value, as well as beta-glucuronidase and acid phosphatase activity examined as markers of lysosomal enzymes, when compared with control rats fed on V.E supplemented diet. Lipid peroxide in the liver tissue also showed significant increase in V.E deficient rats. In contrast, beta-glucuronidase and acid phosphatase in the liver tissue were found to decrease in V.E deficient rats by the administration of D-galactosamine, indicating that the enzymes in the lysosome were entirely released outside the liver cells as a result of cell destruction. It is concluded that the increase of lipid peroxide causes the instability of lysosomal membranes and releases various kinds of hydrolytic enzymes to lead further to cell damage. V.E might act on inhibiting lipid peroxidation to stabilize lysosomal membranes.

Effects of radiopaque material on coronary vascular reserve

The relationship between the increase in coronary blood flow (CBF) following contrast material injection and that following temporary occlusion was studied in the anesthetized dogs. The peak flow following a contrast injection was almost equivalent to the peak reactive hyperemia flow following a 10 sec occlusion (r equeals 0.86). An increase in coronary sinus blood oxygen pressure (Pcso2) occured in associated with an increase in CBF. Administration of dipyridamole diminished the increment of CBF following contrast injection with little changes in Pcso2. Thus, in the coronary system the increase in CBF after contrast injection, similar to that observed after temporary occlusion, is related to coronary vascular reserve and measurement of Pcso2 after coronary arteriography might be an aid to evaluate the coronary vascular reserve.