Effect of percutaneous transluminal coronary angioplasty on exercise ventilation in patients with coronary artery disease and normal left ventricular function

We evaluated the ventilatory response to exercise before and after percutaneous transluminal coronary angioplasty (PTCA) in 22 patients with coronary artery disease (CAD) and normal left ventricular systolic function to determine the effect of exercise-induced myocardial ischemia on the ventilatory response. Subjects performed a symptom-limited maximal ergometer exercise test in the sitting position. The ventilatory response was evaluated in terms of the slopes of minute ventilation (VE) and carbon dioxide production (VCO2) during exercise (slope 1 and slope 2, defined as below and above the respiratory compensation threshold, respectively). Slope 1 of the correlation between (VE) and (VCO2) was significantly greater in patients with CAD (27.3 +/- 2.6) than in the age-matched control group (23.7 +/- 2.6; p < 0.01). Slope 2 was also significantly greater in patients (41.0 +/- 4.8) than in the control group (29.7 +/- 2.9; p < 0.01). Slope 1 of the correlation between (VE) and (VCO2) decreased significantly in the 14 patients in whom PTCA was successful but did not decrease in the 8 patients in whom PTCA failed. Our results suggest that myocardial ischemia increases exercise ventilation in patients with CAD and normal left ventricular systolic function and that its effect is reversible.

Vasoconstriction by endothelin-1 in resistance and conduit portions of isolated human mesenteric arteries

Although physiological processes related to vascular function differ greatly between resistance arteries and conduit arteries, it is not known whether the effects of endothelin-1 on these arteries differ in humans. In the present study, the conduit portion and the resistance portion of isolated human mesenteric arteries were suspended in a Krebs-Ringer solution. Norepinephrine and endothelin-1 produced concentration-dependent contractions in both portions. The EC50 value of norepinephrine in the resistance portion (3.7 x 10(-7) M, n = 8) did not differ from that in the conduit portion (3.4 x 10(-7) M, n = 7). However, the EC50 value of endothelin-1 in the resistance portion (3.0 x 10(-9) M, n = 8) was significantly lower than that in the conduit portion (1.1 x 10(-8) M, n = 7, P < 0.05). Although the maximum response to norepinephrine in the resistance portion (calculated as the percentage of 50 mM KCl-induced contraction) did not differ from that in the conduit portion, the maximum response to endothelin-1 in the resistance portion was significantly greater than that in the conduit portion. These results indicate that endothelin-1 induces more potent constriction in resistance portion than in conduit portion in isolated human mesenteric arteries.

Endogenous endothelin-1 participates in the maintenance of cardiac function in rats with congestive heart failure. Marked increase in endothelin-1 production in the failing heart

BACKGROUND

Although it was demonstrated that circulating endothelin-1 (ET-1) levels are elevated in congestive heart failure (CHF), the production and roles of ET-1 in the failing heart are not known. We investigated the production of ET-1 in the heart and the density of myocardial ET receptors in rats with CHF. We also investigated the effects of intravenously infused BQ-123, an endothelin(A) (ETA) receptor antagonist, on both heart and myocardial contractility in rats with CHF.

METHODS AND RESULTS

We used the left coronary artery-ligated rat model of CHF (CHF rats). Three weeks after surgery, the rats developed CHF. Plasma ET-1 concentration was significantly higher in the CHF rats than in the sham-operated rats (P<.01). In the left ventricle, the expression prepro-ET-1 mRNA was markedly higher in the CHF rats than in the sham-operated rats. The peptide level of ET-1 in the left ventricle was also significantly higher in the CHF rats than in the sham-operated rats (500+/-41 versus 102+/-10 pg/g tissue, P<.01). Myocardial ET receptors were significantly higher in the CHF rats than in the sham-operated rats (243+/-20 versus 155+/-17 fmol/mg protein, P<.05). In the CHF rats, intravenous BQ-123 infusion (0.1 mg x kg(-1) x min(-1) for 120 minutes) significantly decreased both heart rate (P<.01) and LV+dP x dt(max) (P<.05) but not mean blood pressure. BQ-123 infusion did not affect these hemodynamic parameters in the sham-operated rats.

CONCLUSIONS

In the present study, we demonstrated that the production of ET-1 in the heart is markedly increased and that the density of myocardial ET receptors is significantly elevated in the CHF rats. Intravenous BQ-123 infusion significantly reduced both heart rate and LV+dP/dt(max) in the CHF rats but not in the sham-operated rats. Therefore, the ET receptor-mediated signal transduction system in the heart appears to be markedly stimulated in the CHF rats, and endogenous ET-1 may be involved in the maintenance of the cardiac function in these rats.

Long-term effects of doxazosin, an alpha 1-blocker, on serum lipids in hypertensive patients

Nowadays practical antihypertensive therapy involves not only simple normalization of blood pressure but also a reduction of the risks of cardiovascular disease. In this multicenter open-label study, the long-term effects of doxazosin, an alpha 1-adrenergic receptor blocker, on serum lipids were prospectively investigated in 253 patients with essential hypertension. They were treated with doxazosin for 1 year. The averaged the blood pressure was maintained at levels lower than 150/90 mmHg throughout 1 year, but heart rate did not increase. After 3 months of doxazosin therapy, total and low density lipoprotein-cholesterol levels in serum were significantly reduced by 3.3% and 3.4%, respectively, and these levels were maintained throughout the study period. This effect of doxazosin on serum lipids was especially prominent in patients with hypercholesterolemia. In addition, the lipid profile of these patients was favorably altered even when other antihypertensive drugs or lipid-lowering drugs had already been used or were used concurrently. These results constitute useful information for physicians who treat hypertension with alpha 1-blockers to reduce the overall risk of cardiovascular disease.

[Comparison of thrombolytic therapy and direct percutaneous transluminal coronary angioplasty for acute myocardial infarction: prospective multicenter trial at 16 clinical centers in Ibaraki prefecture TUGMI. Tsukuba University Group for Myocardial Infarction]

The efficacies of direct percutaneous transluminal coronary angioplasty (PTCA) and thrombolysis for the treatment of acute myocardial infarction were investigated in 80 patients treated within 12 hours of the onset of myocardial infarction by either PTCA (39 patients) or thrombolytic therapy (41 patients) followed by conservative care. The therapeutic approach was selected according to the treatment strategy at each of the 16 participating centers before the admission of the patients. The two treatment groups were closely matched in clinical characteristics except for the history of hypertension which occurred more in the thrombolysis group (22/39 vs 12/41, p = 0.026). The mean time before starting reperfusion therapy from the onset of symptoms was shorter in the thrombolysis group (2.3 +/- 1.5 vs 5.3 +/- 5.7 hours, p = 0.0001). Chest pain resolved more quickly in the PTCA group. Serial changes in the mean numbers of abnormal Q waves and mean values of the sum of elevated ST-segments on the electrocardiograms were similar in both groups. Serial changes of wall motion abnormality index on echocardiograms were similar in both groups. Coronary angiography after 4 weeks showed the thrombolysis group had greater residual luminal stenosis in the infarct-related artery. Left ventriculography after 4 weeks showed the PTCA group had better mean ejection fraction (68.1 +/- 11.2% vs 58.7 +/- 14.2%, p = 0.0263). Death (3/39 vs 1/41) and cardiac events (6/39 vs 6/41) after 4 weeks were similar in both groups. There was no significant difference in death and cardiac events between these two groups. However, the PTCA group had less severe residual luminal stenosis in the infarct-related artery and better left ventricular function after 4 weeks than the thrombolysis group.

Calcitonin gene-related peptide (CGRP) induces more potent vasorelaxation in the resistance portion than in the conduit portion of mesenteric arteries in humans

Although physiological processes related to vascular function differ greatly between resistance arteries and conduit arteries, it is not known whether the effects of calcitonin gene-related peptide (CGRP), a vasodilator neuropeptide, on these arteries differ in humans. In the present study, the conduit portion and the resistance portion of isolated human mesenteric arteries were suspended in a Krebs-Ringer solution. CGRP produced vasorelaxations in both portions. The EC50 values were very low both in the resistance portion (2.4 x 10(-9) M, n = 7) and in the conduit portion (2.2 x 10(-9) M, n = 7). The maximum response to CGRP in the resistance portion was significantly greater than that in the conduit portion (94.6 +/- 4.0% vs. 64.1 +/- 2.6% relaxation of methoxamine-induced precontraction, both n = 7, p < 0.01). These data suggest that CGRP is one of the most potent endogenous vasodilators in both the resistance portion and the conduit portion of the human mesenteric arteries, and that CGRP induces more potent vasorelaxation in the resistance portion than in the conduit portion of these arteries.

Resting asynchronous left ventricular contraction abnormality analyzed by a phase method in spastic angina pectoris

Quantitative phase analysis of equilibrium ventriculography was performed to study the character of left ventricular (LV) wall motion abnormalities in patients with spastic angina pectoris, who may have clinically and electrocardiographically silent ischemia combined with myocardial stunning, during rest and hyperventilation stress testing.

METHODS

Phase analysis of the left ventricle at rest was performed by equilibrium radionuclide ventriculography in 13 control subjects and 36 patients with spastic angina pectoris. First-pass methodology along with hyperventilation stress testing was performed to assess spasm occurrences. Phase analysis of equilibrium multigated blood-pool scintigrams was performed to evaluate LV asynchrony at rest.

RESULTS

The mean s.d. of LV phase distribution in the patients with variant and vasospastic angina was greater than that in the healthy control subjects (11.28 +/- 1.79 and 10.02 +/- 1.57 degrees versus 6.16 +/- 1.07 degrees). In addition, the mean s.d. of LV phase distribution in the variant angina group was greater than that in the vasospastic angina group. Furthermore, a linear correlation was found between the s.d. of LV phase distribution at rest and the percent decrease in ejection fraction during hyperventilation stress.

CONCLUSION

Asynchronous LV contraction without significant hypokinesis was detected at rest in spastic angina pectoris. The severity of this asynchronous contraction corresponded well with decreases in ejection fraction during hyperventilation stress testing. Thus, analysis of the s.d. of LV phase distribution at rest is expected to provide useful information regarding LV asynchrony in spastic angina pectoris.

Effects of L- and DL-carnitine on patients with impaired exercise tolerance

We designed this study to determine whether orally administered L- and DL-carnitine can improve exercise tolerance in a group of patients with exercise intolerance. Nineteen patients with cardiac disease were randomly divided into 2 groups, an L-carnitine treatment group (n = 9) and a DL-carnitine treatment group (n = 10). Eight additional age-matched patients served as an untreated control group. Subjects in both carnitine treatment groups underwent cardiopulmonary exercise testing on a cycle ergometer in order to determine peak exercise time, peak oxygen uptake (VO2), lactate threshold (LT) and ventilatory threshold (VT) before and after the oral administration of 900 mg/day of L- or DL-carnitine for 2 weeks. Basal values of peak exercise time, peak VO2, LT and VT did not differ significantly among the 3 groups. Peak exercise time and peak VO2 tended to be increased in the L-carnitine treatment group, and tended to be decreased in the DL-carnitine treatment group. Both LT and VT (ml/kg/min) were significantly improved (LT: from 9.7 +/- 0.6 to 10.8 +/- 1.0, p < 0.05; VT: from 9.8 +/- 0.8 to 11.8 +/- 1.9, p < 0.02) by the administration of L-carnitine, while LT was significantly decreased (from 11.0 +/- 2.0 to 9.6 +/- 1.2, p < 0.05) and VT tended to be decreased by the administration of DL-carnitine (from 11.6 +/- 2.0 to 10.8 +/- 2.4). In the untreated control group, no significant changes were observed in the values of exercise tolerance between the 2 series of exercise testings. In neither group did carnitine modify hemodynamic parameters at rest or during exercise. In conclusion, this study demonstrated that L-carnitine increases and DL-carnitine decreases exercise tolerance in patients with impaired exercise tolerance.

The diversity of left ventricular responses to isoproterenol and dibutyryl cyclic AMP infusion in patients with dilated cardiomyopathy

Sixteen patients with dilated cardiomyopathy were studied to define the abnormality of the beta-adrenergic pathway non-invasively, using echocardiographic left ventricular responses to isoproterenol (ISP; 0.02 microgram/kg/min) and dibutyryl cyclic AMP (DBcAMP; 0.1 mg/kg/min) infusion. The increase in fractional shortening induced by ISP (delta FS-ISP) was 9 +/- 6% and that by DBcAMP (delta FS-DBcAMP) was 7 +/- 3%. The patients could be divided into three groups according to their left ventricular response to each agent: Group A; normal response to ISP (delta FS-ISP > or = 11%), Group B-1; poor response to ISP but better response to DBcAMP (delta FS-ISP < 11%, delta FS-DBcAMP > or = 7%; damage to beta-receptors), and Group B-2; poor response to ISP and DBcAMP (delta FS-ISP < 11%, delta FS-DBcAMP < 7%; damage including post receptor levels). Seven patients were in Group A, four in Group B-1, and five in Group B-2. DCM patients had a diversity of left ventricular responses to ISP and DBcAMP, according to the site of damage in the beta-adrenergic pathway.

Response to isoproterenol as a prognostic indicator of evolution from hypertrophic cardiomyopathy to a phase resembling dilated cardiomyopathy

OBJECTIVES

We sought to assess whether isoproterenol stress echocardiography could detect in advance in which patients hypertrophic cardiomyopathy would progress to a phase resembling dilated cardiomyopathy.

BACKGROUND

In a few patients, hypertrophic cardiomyopathy has been reported to progress to a phase characterized by systolic dysfunction and left ventricular dilation, resembling dilated cardiomyopathy.

METHODS

Echocardiograms were recorded before and immediately after intravenous infusion of isoproterenol (0.02 microgram/kg body weight per min) for 5 min in 18 patients with typical hypertrophic cardiomyopathy (i.e., hypertrophied, hyperdynamic and nondilated) to determine the difference in fractional shortening. The patients were categorized into those with a good response (difference in fractional shortening > 7%, 14 patients) and those with a poor response (difference < or = 7%, 4 patients). Changes in left ventricular end-diastolic diameter and fractional shortening were evaluated by using serial echocardiography over an average follow-up period of 5.4 years.

RESULTS

In the good response group, neither end-diastolic diameter nor fractional shortening changed significantly during the follow-up period. In the poor response group, end-diastolic diameter significantly increased from a mean +/- SD of 41 +/- 5 to 53 +/- 5 mm (p < 0.05), and fractional shortening significantly decreased from 40 +/- 12% to 29 +/- 10% (p < 0.05). All patients in the poor response group showed a substantial decrease (> or = 5%) in fractional shortening and an increase (> or = 5 mm) in end-diastolic diameter. One patient developed congestive heart failure due to systolic dysfunction during the observation period.

CONCLUSIONS

The present study confirmed that impaired responses to isoproterenol infusion are related to future deterioration of left ventricular performance in patients with typical hypertrophic cardiomyopathy.

Malignant hyperthermia in a patient with Becker muscular dystrophy: dystrophin analysis and caffeine contracture study

We present a 17-year-old boy with Becker muscular dystrophy (BMD) who developed hyperthermia and heart failure after general anesthesia. He presented clinical features of malignant hyperthermia (MH), and had masseter spasm and elevated body temperature (38.7 degrees C) with very high serum CK activity (107,000 IUl-1). Dystrophin tests confirmed a clinical diagnosis of BMD in the patient, i.e. faint and patchy immunostaining pattern of skeletal muscle, truncated dystrophin protein and a deletion of exons 3 and 4 of the dystrophin gene. To inquire into the mechanism of MH associated in the patient, we tested caffeine contracture reaction by the skinned fiber method. We found an increased sensitivity to caffeine only in type 1 muscle fibers. The rate of Ca(2+)-induced Ca2+ release (CICR) was normal, suggesting that the mechanism of "MH" observed in our patient with BMD is not the same as that of classical MH. A possible mechanism might be related to derangements of the sarcoplasmic reticulum membrane in BMD, which sensitize the membrane to caffeine or other agents.

Exercise-induced rise in arterial potassium is enhanced in patients with impaired exercise tolerance

We assessed the changes in arterial potassium concentration during exercise and recovery in relation to exercise tolerance in patients with impaired exercise tolerance. Sixteen patients with cardiac disease were subjected to a cardiopulmonary exercise test on a cycle ergometer. Arterial potassium and lactate concentrations were measured every minute during and after exercise, and ventilatory threshold (VT) and lactate threshold (LT) were identified. Before exercise, arterial potassium concentration was 3.8 +/- 0.3 mEq/l. It increased to 4.1 +/- 0.3 mEq/l at LT (p < 0.002 versus at rest), to 4.2 +/- 0.3 mEq/l at VT, and to 4.8 +/- 0.5 mEq/l at peak exercise (p < 0.001 versus at LT, p < 0.001 versus at VT). At an exercise intensity equivalent to 30, 40, 50 or 60% of predicted maximum oxygen uptake, the increase in arterial potassium showed a negative and significant correlation with %LT (r = -0.62 approximately -0.72, p < 0.01 approximately 0.05) and %VT (r = -0.62 approximately -0.75, p < 0.001 approximately 0.05), where %LT and %VT represent the ratios of LT and VT to the predicted maximum oxygen uptake, respectively. There was a good correlation between the rate of fall in potassium concentration during recovery and its increase during exercise. It was concluded that in patients with impaired exercise tolerance, the greater the degree of exercise intolerance, the greater the increase in arterial potassium concentration during exercise, and the steeper the fall in potassium concentration during recovery. Because the rise in potassium concentration during exercise and its fall during recovery were greater when the exercise level exceeded the anaerobic threshold, exercise levels below the anaerobic threshold are recommended for patients with cardiac diseases.

Chronically decreased aortic distensibility causes deterioration of coronary perfusion during increased left ventricular contraction

OBJECTIVES

This study investigated the long-term effects of decreased aortic distensibility on the heart in relation to coronary perfusion.

BACKGROUND

Aortic distensibility is decreased in patients with atherosclerosis and hypertension and in the elderly. However, the effect of a long-term decrease in aortic distensibility on coronary perfusion has not been fully investigated.

METHODS

Twelve anesthetized dogs underwent thoracotomy and were allocated to two groups: Group I included six control dogs with a normal aorta; Group II included six dogs with decreased aortic distensibility produced by banding the descending aorta. After 4 to 6 weeks, the dogs had a second operation to measure coronary artery flow and transmural flow distribution. Because the effect of decreased aortic distensibility on coronary perfusion may be affected by ventricular contractility, measurements were performed at baseline and during increased ventricular contraction induced by isoproterenol infusion.

RESULTS

At baseline, arterial compliance was reduced by 35% in Group II, but there was no change in total mean arterial resistance. Hemodynamic variables, regional wall motion and coronary flow were also similar in both groups. However, during isoproterenol infusion, coronary flow increased more in Group II than in Group I (p < 0.01), and the coronary flow reserve ratio (maximal peak hyperemic flow divided by rest flow) decreased more in Group II than in Group I (mean [+/- SD] 1.9 +/- 0.4 vs. 2.4 +/- 0.3, p < 0.05). Moreover, although the transmural flow distribution was similar in the two groups at baseline, during isoproterenol infusion the endocardial flow increased less in Group II than in Group I (p < 0.05), and the endocardial/epicardial flow ratio was significantly decreased in Group II compared with Group I (mean [+/- SD] 0.70 +/- 0.18 vs. 0.99 +/- 0.22, p < 0.05). The subendocardial electrocardiogram showed ST segment elevation during isoproterenol infusion in Group II (p < 0.05) but not in Group I.

CONCLUSIONS

These results demonstrate that during increased ventricular contraction, chronically decreased aortic distensibility contributes to a further decrease in the coronary flow reserve ratio, impairs endocardial blood flow and may induce subendocardial ischemia even in the absence of coronary artery stenosis.

[A case of acute pandysautonomia and diffuse brain stem impairment associated with EB virus infection]

A 37-year-old woman with complaints of headache and nausea presented with temporary disturbance of consciousness, bulbar palsy and ataxic speech following flu-like symptoms. After the recovery of her consciousness, she developed orthostatic syncope and numbness all over the body. When she was admitted to our hospital two months later, she showed emaciation, diminished sweat production and butterfly-patch-like pigmentation. Neurologic examinations were remarkable for anisocoric pupils that sluggishly reacted to light, impaired left facial movements, bulbar palsy, numbness of the whole body, total loss of all tendon reflexes, incordination, ataxic gait and severe postural hypotension. Laboratory data included albuminocytogenic dissociation in cerebrospinal fluid, convergence nystagmus and dysmetria in electronystagmography, and right trigeminal paralysis in blink reflex. A sural nerve biopsy showed active axonal degeneration and severe loss of both myelinated and unmyelinated fibers. Examinations of autonomic nervous system disclosed diffuse impairment of sympathetic and parasympathetic postganglionic nerve. Based on these findings she was diagnosed as having acute pandysautonomia. High titer of serum EB virus antibody suggested that acute pandysautonomia and diffuse brainstem impairment may be related to EB virus infection.

Ventricular wall stress revisited. A keystone of cardiology

Wall stress has been used as one of the parameters of myocardial mechanics. The present review focuses on recently developed data on ventricular wall stress, especially in relation to other newly developed areas in cardiology. In hypertensive hearts, there is a broad continuous spectrum in the structural and functional changes: those with low wall stress (inappropriate hypertrophy), those with normal wall stress (appropriate hypertrophy) and those with high wall stress (inadequate hypertrophy). Among them, the responses to neurohumoral stimuli are various, and their clinical features and courses also varied. These differences in wall stress among the different categories of hypertensive hearts may be caused by the variable influences of non-mechanical factors, such as molecular, metabolic and neurohumoral ones. Wall stress is an essential determinant of myocardial oxygen consumption, and is also an important determinant of the myocardial contractile state and diastolic function. In contrast to excitation-contraction coupling, contraction-excitation feedback has been studied, suggesting the importance of wall stress regulating electrical phenomena. The interrelationship between mechanical factors (including wall stress) and non-mechanical factors (including molecular, metabolic, neurohumoral and genetic ones) has been investigated intensively. In conclusion, wall stress (or force on the myocardial cell) may be a keystone in cardiology, relating to each of the cardiac phenomena. If wall stress deviates from the normal range, even with compensatory mechanisms, severe cardiac events occur. The compensatory mechanisms for wall stress may act as a risk factor on the heart, especially when the wall stress remains outside the normal range.

Two cases of acute myocardial infarction associated with aplastic anemia during treatment with anabolic steroids

Thrombosis is a rare complication in patients with aplastic anemia because of the presence of coincidental thrombocytopenia. We have recently treated two cases, a 61-year-old male and a 59-year-old female, with acute myocardial infarction associated with aplastic anemia. Although their platelet counts were lower than normal in spite of treatment with anabolic steroids for aplastic anemia, the coronary angiographic findings strongly suggested coronary thrombosis in both cases. Anabolic steroids, which have been commonly used for the treatment of aplastic anemia, are a possible risk factor for coronary thrombosis because they have an accelerating effect on thrombus formation. We report two very rare but clinically important cases.

Increase in the chemically-induced differentiation of human leukemia cell lines by tubulin disruptors

The effect of various structural/functional tubulin disruptors (including colchicine-type disruptors, vinblastine, rhizoxin, maytansine, peptide-type disruptors, and taxol) on the chemically induced differentiation of human leukemia cell lines (HL-60 and K562) was examined. As differentiation-inducing agents, 12-O-tetradecanoylphorbol-13-acetate (TPA) was used for the differentiation of both HL-60 and K562 to monocyte/macrophages, retinoids were used for the differentiation of HL-60 to mature granulocytes, and hemin was used for the erythroid differentiation of K562. All the tubulin disruptors investigated increased the chemically-induced differentiation of HL-60 and K562 cell lines to the cognate mature cell types, regardless of the nature of the differentiation.

Endothelin receptor subtypes in human versus rabbit pulmonary arteries

We studied which endothelin (ET) receptor subtypes mediate ET-1-induced vasocontraction in the human pulmonary artery (PA) compared with the rabbit PA. ET-1 produced potent contraction in both human and rabbit isolated PAs. In human PA, ET-1-induced contraction was competitively antagonized by BQ-123 (an ETA receptor antagonist) with a pA2 value of 7.68. In rabbit PA, however, even a high concentration of BQ-123 (1 microM) did not affect the contraction. BQ-3020 (an ETB receptor agonist) produced potent contraction in rabbit PA but not in human PA. Binding assays of the membrane preparations showed that human and rabbit PAs contained ETA and ETB receptors in ratios of 93:7 and 23:77, respectively. These results suggest interspecies differences in the ET receptor subtypes that mediate ET-1-induced vasocontraction; ETA receptors are dominant in the human PA, whereas ETB receptors are dominant in the rabbit PA. Furthermore, the predominance of ETA receptors in human PA was supported by autoradiographical studies. If ET-1 acts as a physiological and/or pathophysiological vasocontractor in the human pulmonary circulation, an ETA receptor antagonist would function as a pulmonary vasodilator in humans.

[Characteristics of myocardial diseases in the elderly]

Myocardial diseases consist of cardiomyopathy of unknown origin and specific myocardial diseases of known origin. The former consists mainly of dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). In the latter, cardiac amyloidosis may be most frequently seen in the elderly. One hundred and twenty patients with cardiomyopathy were studied concerning their clinical courses. They were divided into 2 groups; i) young-middle-aged (Y) and ii) elderly (0). Group 1 was divided into 2 subgroups: 1a) followed up to an age less than 60 years old, and 1b) followed up to beyond age 60. In DCM, left ventricular posterior wall thickness and left atrial diameter increased significantly in the elderly. In HCM, young patients had obstructive type disease more frequently than the elderly. A history of mild hypertension was found more frequently in the middle-aged or elderly than in the young. Left ventricular end-diastolic diameter increased and left ventricular wall thickness decreased significantly in the elderly. Many patients with DCM usually die of congestive heart failure with ventricular arrhythmia, and those with HCM, both young or middle-aged, often die suddenly during sports activity. If there is an adaptive system, such as increased wall thickness in DCM or decreased wall thickness and increased diameter in HCM, which may contribute to the normalization of left ventricular wall stress, the patients might be able to survive to old age.

Decreased adrenergic response in hypertensive patients without left ventricular hypertrophy

To analyze the adrenergic responses and to compare them between hypertensive patients with and without left ventricular hypertrophy (LVH), left ventricular (LV) fractional shortening (FS) and end-systolic wall stress (ESS) were measured by echocardiography and the inotropic response to the infusion of isoproterenol (0.02 micrograms/kg/min for 5 min) was studied in 25 hypertensive patients without LVH [H(-)] and 30 hypertensive patients with LVH [H(+)]. LVH was determined by echocardiography. Age, gender, heart rate, systolic and diastolic blood pressures, LV end-systolic and end-diastolic diameters, and FS were matched between the groups. The tests were performed before introduction of antihypertensive treatment or 4 weeks after its discontinuation. ESS showed a significant inverse linear relation with FS in all the subjects before isoproterenol infusion. The inotropic response to isoproterenol was measured as the increase of FS corrected for the decrease of ESS (delta FS/-delta ESS), that is, the slope of the change of the relation between FS and ESS. The change in delta FS/-delta ESS was significantly smaller (0.49 +/- 0.15 cm2/g, mean +/- SD) in H(-) than in H(+) patients (1.01 +/- 0.57 cm2/g) (p < 0.001). It is concluded that, compared with the H(+) group, adrenergic response is depressed in H(-) patients. This depression might be etiologically related to the phenomenon that LVH did not develop in the H(-) group in spite of the same level of pressure load as in the H(+) group.

Visualization of penetrating transmural arteries in situ by monochromatic synchrotron radiation

BACKGROUND

Penetrating transmural arteries with a diameter of < 500 microns are considered to be a critical vascular component that causes a transmural variation of myocardial blood flow under various pathophysiological conditions. However, the conventional coronary angiographic system is not oriented to the visualization of such small arteries as these.

METHODS AND RESULTS

We magnified and monochromatized the inherently narrow beam (3 mm along the vertical direction) of synchrotron radiation by using an asymmetrically cut silicon crystal with 311 reflecting planes to obtain a monochromatic x-ray with relatively large beam size (60 x 25 mm) and with an energy of just above (+130 eV) the K-absorption edge of the contrast materials (33.17 and 37.41 ke V for iodine and barium, respectively). We irradiated dogs or excised hearts with the monochromatic x-ray and obtained coronary angiograms using an image intensifier and video system with a spatial resolution of 170 microns. In the anesthetized dog experiments, we visualized the transmural penetrating arteries (5 to 15 mm in length) arising every 4 to 7 mm from the epicardial branch. Visualization of these arteries filled with heavy element-loaded microspheres (15 microns in diameter) in the excised-heart experiments, in which the monochromatic x-ray was irradiated to the hearts through a 10- to 20-cm acrylic plate, indicated that this system could be used for human patients, in whom body absorption of x-ray is substantial.

CONCLUSIONS

Coronary angiogram by means of monochromatic x-ray is useful for a precise evaluation of coronary circulation, both in clinical setting and in physiological animal experiments.

Contribution of endogenous endothelin-1 to the progression of cardiopulmonary alterations in rats with monocrotaline-induced pulmonary hypertension

Endothelin-1 (ET-1) is known to have potent contractile and proliferative effects on vascular smooth muscle cells and is known to induce myocardial cell hypertrophy. We studied the pathophysiological role of endogenous ET-1 in rats with monocrotaline-induced pulmonary hypertension. Four-week-old rats were given a single subcutaneous injection of 60 mg/kg monocrotaline (MCT rats) or saline (control rats) and were killed after 6, 10, 14, 18, and 25 days. In the MCT rats, right ventricular systolic pressure progressively increased and right ventricular hypertrophy developed in a parallel fashion. The venous plasma ET-1 concentration also progressively increased, and this increase preceded the development of pulmonary hypertension. The isolated pulmonary artery exhibited a significantly weaker response to ET-1 in the MCT rats on day 25 but not on days 6 and 14. In the MCT rats, the expression of prepro ET-1 mRNA as measured by Northern blot analysis significantly increased in the heart on days 18 and 25, whereas it gradually decreased in the lungs. The peptide level of ET-1 in the lungs also significantly decreased in the pulmonary hypertensive stage. The expression of prepro ET-1 mRNA had increased by day 6 only in the kidneys. Continuous infusion of BQ-123, a selective ETA receptor antagonist, by an osmotic minipump (14.3 mg per day per rat for 18 days) significantly inhibited the progression of both pulmonary hypertension (right ventricular systolic pressure, 77.8 +/- 4.2 [mean +/- SEM] mm Hg [n = 10] versus 52.3 +/- 2.4 mm Hg [n = 7]; P < .01) and right ventricular hypertrophy (right ventricle/[left ventricle +/- septum], 0.56 +/- 0.03 [n = 10] versus 0.41 +/- 0.02 [n = 7]; P < .01). Histological examination revealed that BQ-123 also effectively prevented pulmonary arterial medial thickening. The inhibition of right ventricular hypertrophy by BQ-123 may be partly ascribed to the blockade of excessive stimulation of the heart by ET-1, in addition to the prevention of pulmonary hypertension. The present findings suggest that endogenous ET-1 contributes to the progression of cardiopulmonary alterations in rats with MCT-induced pulmonary hypertension.

Increased production of endothelin-1 in the hypertrophied rat heart due to pressure overload

Endothelin-1 (ET-1) has been demonstrated to induce hypertrophy in cultured cardiac myocytes. We investigated the production of ET-1 in the heart of aorta-banded rats in vivo. Seven days after the banding of the abdominal aorta, rats developed a significant left ventricular hypertrophy. The tissue content of mature ET-1 and the level of expression of prepro ET-1 mRNA were higher in the left ventricle of aorta-banded rats than in those of sham-operated rats. The expression of prepro ET-1 mRNA in the right ventricle was not different between the two groups. These findings indicate that the production of ET-1 increased in the hypertrophied left ventricle, thereby suggesting the possible involvement of endogenous ET-1 in the development of cardiac hypertrophy due to pressure overload.

Safety and efficacy of amlodipine. A new once-daily calcium antagonist in non-hypertensive patients with coronary artery disease

To analyze the effects of the treatment of 5 mg amlodipine on blood pressure and heart rate with a 24-hour ambulatory blood pressure monitoring device and to evaluate its antiischemic efficacy using treadmill exercise testing, 7 non-hypertensive patients with coronary artery disease were studied. The systolic and diastolic blood pressure and heart rate recorded over the entire day and during daytime did not change significantly after the treatment. On the other hand, the systolic blood pressure decreased significantly at night (122 +/- 19-->113 +/- 17 mmHg, p < 0.05) after treatment, but the change can be considered to be within the physiological range. Exercise duration increased significantly after the administration of amlodipine (9.7 +/- 4.8-->11.1 +/- 4.9 min, p < 0.05). Systolic blood pressure, heart rate and rate-pressure product decreased significantly and in addition, ST segment depression was significantly less marked (-0.25 +/- 0.09-->-0.21 +/- 0.09 mV, p < 0.05) after treatment, when compared at the same level of work load. Therefore, the new once-daily calcium antagonist amlodipine is safe and efficacious in non-hypertensive patients with coronary artery disease.

Unusual electrocardiographic findings associated with type A Wolff-Parkinson-White syndrome

A 50-year-old woman with Wolff-Parkinson-White (WPW) syndrome presented with unusual electrocardiographic (ECG) findings following the termination of paroxysmal supraventricular tachycardia. The ECG showed three different QRS complexes and irregular R-R intervals. These QRS complexes consisted of: (1) narrow QRS; (2) wide QRS with delta wave; and (3) wide QRS with left bundle branch block (LBBB). The mechanisms of these findings, revealed by electrophysiological study, were: (1) intermittent anterograde left-sided accessory pathway conduction; (2) rate-dependent ipsilateral LBBB; and (3) intermittent retrogradely conducted atrial echoes that occurred due to intraventricular conduction delay resulting from LBBB. Cases of WPW syndrome with these unusual ECG findings, which were clearly interpreted by electrophysiological study, are rare.

Age-related changes of sinus node function and autonomic regulation in subjects without sinus node disease--assessment by pharmacologic autonomic blockade

To assess the relationship between aging and autonomic regulation of sinus node function, 56 subjects of various ages (range 14-75 years, mean 43 +/- 19 years) without sinus node disease were studied. Heart rate, corrected sinus node recovery time and sinoatrial conduction time were measured before (basic) and after (intrinsic) pharmacologic autonomic blockade (propranolol + atropine i.v.). Percent chronotropies of the above parameters were calculated by a modified Jordan's method. Basic heart rate and basic corrected sinus node recovery time did not vary with age (r = -0.15, r = 0.08, respectively), while basic sinoatrial conduction time tended to increase with age (r = 0.32, p < 0.05). Intrinsic heart rate decreased (r = -0.76, p < 0.001), and intrinsic corrected sinus node recovery time and intrinsic sinoatrial conduction time both increased with age (r = 0.55, p < 0.001; r = 0.56, p < 0.001, respectively). The younger the subject, the more negative the percent chronotropies of the above parameters were, and the percent chronotropies correlated positively with age (r = 0.68, p < 0.001; r = 0.52, p < 0.001 and r = 0.34, p < 0.05, respectively). In conclusion, intrinsic sinus node functions deteriorated with age. Furthermore, parasympathetic tone on the sinus node functions decreased with age, which may compensate for age-related deterioration of intrinsic sinus node function.

Platelet cyclic GMP. A potentially useful indicator to evaluate the effects of nitroglycerin and nitrate tolerance

BACKGROUND

The present study was designed to investigate the intracellular production of cyclic GMP (cGMP) in platelets in response to nitroglycerin and to determine the potential clinical value of platelet cGMP as an indicator of the effects of nitroglycerin and nitrate tolerance.

METHODS AND RESULTS

Platelet cGMP levels and the diameters of the coronary arteries before and 2 minutes after intracoronary injection of 200 micrograms nitroglycerin were measured in 15 patients who had previously received nitrates (nitrates group) and in 16 who had not received any nitrates (no-nitrates group). Platelet cGMP levels increased significantly after nitroglycerin injection in the two groups, but plasma cGMP levels and plasma atrial natriuretic peptide levels did not change. The percent increase in platelet cGMP levels and the percent dilatation of the left anterior descending (LAD) and left circumflex (LCx) coronary arteries after nitroglycerin injection were higher in the no-nitrates group than in the nitrates group (platelet cGMP levels: artery, 74.2 +/- 18.3% versus 11.5 +/- 4.2%, P < .01; vein, 73.6 +/- 22.9% versus 9.0 +/- 3.1%, P < .01; coronary dilatation: LAD, 46.7 +/- 6.0% versus 9.9 +/- 2.5%, P < .01, LCx, 51.2 +/- 8.7% versus 6.1 +/- 3.0%, P < .01). The percent increase in platelet cGMP levels was significantly correlated with the percent dilatation of the coronary arteries (LAD: r = .90, P < .01; LCx: r = .92, P < .01) in the no-nitrates group and not in the nitrates group.

CONCLUSIONS

These results indicate that platelet cGMP can be used as an indicator for in situ evaluation of nitroglycerin effects and that patients who have received nitrates develop nitrate tolerance, which affects intracellular production of cGMP and vasodilation in the response to nitroglycerin.

Coronary circulation in dogs with an experimental decrease in aortic compliance

OBJECTIVES

This study was designed to investigate the effects of decreased aortic compliance on the coronary circulation.

BACKGROUND

A decrease in aortic compliance due to arteriosclerosis is observed in patients with coronary artery disease. However, the effects of decreased aortic compliance on the coronary circulation have not yet been investigated sufficiently.

METHODS

Hemodynamics, subendocardial electrocardiogram (ECG), myocardial segmental length and myocardial blood flow were investigated in six dogs with aortic bandaging (bandaged group) and five dogs with a sham operation (control group) at rest and during pacing 4 weeks after surgery.

RESULTS

Aortic compliance in the bandaged group was less than that in the control group (0.24 +/- 0.20 vs. 0.50 +/- 0.22 ml/mm Hg, p < 0.05). Pulse pressure and the tension-time index were significantly greater in the bandaged group than in the control group, but systemic vascular resistance was not altered significantly. The subendocardial/subepicardial flow ratio was lower in the bandaged group than in the control group (0.95 +/- 0.31 vs. 1.57 +/- 0.26, p < 0.05). In the region supplied by the left circumflex artery with a stenosis that was adjusted to eliminate reactive hyperemia, rapid atrial pacing (heart rate 200 beats/min) further decreased endocardial flow and the endocardial/epicardial flow ratio in the bandaged group. Moreover, both the reduction of segmental shortening and the ST elevation on the subendocardial ECG in the left circumflex-supplied region during pacing were greater in the bandaged group.

CONCLUSIONS

These results indicate that decreased aortic compliance greatly increases the risk of subendocardial ischemia in the presence of coronary stenosis.

Altered expression of ETB-receptor mRNA in the lung of rats with pulmonary hypertension

To investigate the pathophysiologic role(s) of endothelin-1 (ET-1) in pulmonary hypertension, we studied the expression of ETB-receptor mRNA in the lung and venous plasma concentrations of ET-1 in rats with monocrotaline-induced pulmonary hypertension (PH). Three weeks after s.c. injection of monocrotaline (60 mg/kg), rats (PH rats, n = 6) were sacrificed. Vehicle-injected rats (n = 6) served as controls. The right ventricular systolic pressure of PH rats [58.0 +/- 4.7 mm Hg (mean +/- SEM)] was significantly higher than that in the vehicle-treated control rats (29.2 +/- 2.1; p < 0.01). Northern blot analysis showed that the expression of ETB-receptor mRNA decreased in the lung of PH rats. The venous plasma concentration of ET-1 measured by a sandwich-enzyme immunoassay was significantly higher in PH rats than in control rats (5.1 +/- 0.7 versus 1.3 +/- 0.2 pg/ml; p < 0.01). The present findings suggest that the expression of ETB-receptor mRNA decreases in the lung of PH rats, which might be closely related to the increase in plasma ET-1 concentration in these rats.

Decreased aortic compliance aggravates subendocardial ischaemia in dogs with stenosed coronary artery

OBJECTIVES

The existence of decreased aortic compliance due to arteriosclerosis has been documented in patients with coronary artery disease. The aim of this study was to investigate the effects of decreased aortic compliance on coronary artery disease.

METHODS

To simulate coronary artery disease, a fixed stenosis was made in the left circumflex coronary artery in dogs. Ten anaesthetised open chest dogs were used. Aortic compliance was decreased by banding the thoracic aorta with adjustable plastic rings. The level of coronary stenosis was adjusted to reduce the baseline flow by no more than 10% but enough to eliminate reactive hyperaemia induced by a 10 s occlusion. Measurements of haemodynamics, regional myocardial segment length, subendocardial ECG, and myocardial tissue PO2 were performed at five stages (initial control stage, rest and pacing stages without aortic banding, and rest and pacing stages with the aortic banding).

RESULTS

Haemodynamic variables were not changed at any stage, except for increased pulse pressure secondary to the aortic banding. During pacing with aortic banding, subendocardial PO2 (Endo) levels were decreased, and subepicardial PO2 (Epi) levels were increased, compared to those without the aortic banding [Endo: 43.2(SD 9.8) v 36.8(10.0) mm Hg, p < 0.05; Epi: 34.0(11.5) v 44.4(7.9) mm Hg, p < 0.05]. ST elevation on the subendocardial ECG was greater, and myocardial segment shortening was less with the aortic bandage during pacing.

CONCLUSIONS

When the work of the heart is increased, a decrease in aortic compliance tends to compromise ischaemic myocardium further in the presence of an induced stenosis of a major coronary artery.

Plasma endothelin-1 concentrations in the coronary sinus in dogs with artificially induced myocardial infarction

We have previously reported the marked increase in plasma levels of endothelin-1 in patients with acute myocardial infarction (AMI). To investigate the effects of severe myocardial ischemia on the production of endothelin-1, plasma concentrations of endothelin-1 were measured by a sandwich-type enzyme immunoassay that we developed recently in both the coronary sinus and the aorta of dogs with artificially induced AMI. Dogs were anesthetized and chests were opened. The proximal left anterior descending coronary artery was completely occluded by ligation for 1 h and then was reperfused for 1 h. Throughout the experiment (at the end of occlusion for 1 h, at the beginning of reperfusion, at the end of reperfusion for 1 h), plasma endothelin-1 levels were not significantly altered either in the coronary sinus or in the aorta. The present findings indicate that severe myocardial ischemia itself does not affect the production of endothelin-1 in the coronary circulation of dogs.

Quantitative phase analysis of myocardial wall thickening by technetium-99m 2-methoxy-isobutyl-isonitrile SPECT

Regional wall thickening was assessed by ECG-gated SPECT using technetium-99m 2-methoxy-isobutyl-isonitrile (99mTc-MIBI). For myocardial segments with an optimal short axis, regional count changes from end-diastole to end-systole were used to calculate the regional wall thickening. Functional images displaying amplitude, % wall thickening (% WT), and phase were generated by a fundamental Fourier analysis. In the control subjects, % WT analysis showed heterogeneous contraction among the left ventricular wall segments. The amplitude values showed a similar pattern to the %WT values. Phase images demonstrated that the timing of ventricular contraction was almost homogenous between the various wall segments. In the CAD patients, regional decreases in amplitude and %WT corresponding to zones of reduced perfusion were shown in the ischemic segments. Phase images also indicated asynchronous contraction in these segments. Phase analysis of regional wall thickening in 99mTc-MIBI scintigraphy seems to be useful for understanding regional myocardial function in combination with perfusion scanning.

Vasoconstrictor effects of endothelin-1 on myocardium microcirculation studied by the Langendorff perfusion method: differential sensitivities among microvessels

An intravital fluorescence microscope system was used to investigate the pharmacological effects of endothelin-1 (ET-1) on the coronary microcirculation in the isolated beating hearts of rats. The heart was perfused by retrograde aortic steady flow with an oxygenated Krebs-Ringer solution containing FITC-dextran. Changes in diameters of coronary microvessels accompanying the cumulative injection of ET-1 in the perfusate were observed and recorded with a video camera system. Coronary perfusion pressure was also measured during each experiment. Bolus injections of ET-1 (1-300 pmole) elicited a dose-dependent increase in perfusion pressure from 54 +/- 6 mm Hg (mean +/- SEM; n = 10, before the ET-1 injection) to 144 +/- 9 mm Hg (n = 8, at the ET-1 dose of 300 pmole). A dose-dependent narrowing of microvessels was also observed. This vasoconstriction was especially prominent in small-sized arterioles; the maximum vasoconstriction of the smaller arterioles was significantly higher than that of the larger arterioles (P less than 0.05). The response induced by ET-1 dose of 3-10 pmole was significantly larger in arterioles than in postcapillary venules in the diameter range between 10 and 40 microns. The vasoconstriction produced by ET-1 was inhomogeneous. Some part of bifurcations of arterioles showed a prominent localized vasoconstriction, and occasionally showed a complete luminal obstruction. Such a segmental vasospasm might be attributed to localized sensitivities of arterioles to ET-1. These findings suggest that ET-1 may have an important role in governing the coronary resistance and regulating the capillary flow in the myocardium.

Left atrial function in ischemic heart disease assessed by intravenous digital subtraction angiography

To investigate changes in left atrial morphology and dimensions during the cardiac cycle, the atrium was visualized by intravenous digital subtraction angiography (DSA). The study subjects consisted of 22 male patients whose average age was 54.5 +/- 8.6 years. They had ischemic heart disease without mitral valve disease and were in sinus rhythm. They were 11 patients with old myocardial infarction (OMI group) and 11 who had chest pain without evidence of infarction (AP group). DSA was performed in the continuous mode. Contrast material (35 ml) was injected at a rate of 18 ml/sec via a catheter in the superior vena cava and subtraction images were obtained at a speed of 30 frames/sec in the right anterior oblique projection. The left atrial and left ventricular margins were traced manually, their areas were calculated, and fractional changes in area were analyzed. The left ventricular ejection fraction (LVEF) was calculated by densitometry. Cardiac catheterization was performed in 16 patients and the left ventricular end-diastolic pressure (LVEDP) and mean pulmonary arterial wedge pressure (PAWP) were measured. The entire left atrium was clearly imaged using DSA. Phase analysis of the time-area curves in the right anterior oblique projection revealed that the left atrial area was maximal during left ventricular end-systole (%LA1 = 100%), it decreased during early left ventricular diastole (%LA2), and then increased slightly again during mid-diastole (%LA3). After left atrial contraction, the minimum area was obtained (%LA4). The left atrium showed a two-stage decrease in the area due to passive emptying and active contraction during left ventricular diastole. Passive emptying (%LA1-%LA2) was significantly less in the OMI group than in the AP group (6.3 +/- 3.6 vs 13.3 +/- 4.8%, p < 0.01, respectively). In all 22 subjects, passive emptying correlated with LVEF (r = 0.70, p < 0.001) and LVEDP (r = -0.58, p < 0.05). There was no difference in active contraction (%LA3-%LA4) between the 2 groups (26.0 +/- 5.7% in the OMI group, 28.2 +/- 8.4% in the AP group), and it did not correlate with LVEF or LVEDP. The ratio of passive emptying to active contraction [(%LA1-%LA2)/(%LA3-%LA4)] correlated with LVEF (r = 0.63, p < 0.01). These findings suggested that impaired left ventricular diastolic function and a relative increase in atrial contraction were present in patients with a lower LVEF. The %LA4 correlated with LVEDP and PAWP (r = 0.65, r = 0.63, p < 0.01, respectively). In conclusion, DSA proved to be a useful method for investigating left atrial morphology and function.

Acute effects of intravenous nicardipine on hemodynamics and cardiac function in patients with a healed myocardial infarction and no evidence of congestive heart failure

Acute effects of intravenous nicardipine (10 micrograms/kg) on systemic hemodynamics and cardiac function were evaluated in 17 patients with a healed myocardial infarction and no evidence of congestive heart failure. Mean New York Heart Association functional class was 1.6 +/- 0.5 (mean +/- standard deviation). Aortic systolic pressure (p less than 0.001) and left ventricular end-diastolic pressure decreased (10 +/- 3 to 8 +/- 3 mm Hg, p less than 0.01), and systemic vascular resistance decreased significantly (p less than 0.001), whereas pulmonary and right atrial pressure and pulmonary arteriolar resistance did not change. Cardiac and stroke indexes showed biphasic changes. Although positive and negative maximal rate of left ventricular pressures decreased significantly (p less than 0.05 and p less than 0.01, respectively), they did not change significantly when aortic systolic pressure was corrected. There was a significant inverse correlation between the negative rate of left ventricular pressure/aortic systolic pressure before nicardipine infusion and its maximal percent increase after infusion (r = -0.56, p less than 0.05), indicating a beneficial effect on diastolic relaxation in patients with impaired diastolic function. Our data show that a low dose (10 micrograms/kg) of intravenous nicardipine exerts a favorable effect on impaired diastolic function, but depresses left ventricular pump function with much less effect on right heart circulation.

Endothelin-1 and endothelin-3 play different roles in acute and chronic alterations of blood pressure in patients with chronic hemodialysis

We measured plasma concentrations of endothelin-1 (ET-1), ET-3 and big ET-1 by sandwich-enzyme immunoassays in patients (Pt) with chronic hemodialysis (HD) (Pt-HD, n = 23) and age-matched normal subjects (NS, n = 17). In Pt-HD, plasma levels (before HD) of ET-1, ET-3 and big ET-1 were significantly higher than those in NS. Reverse-phase HPLC analysis indicated that plasma concentrations of ET-1, ET-3 and big ET-1 in both Pt-HD and NS can be precisely measured by these sandwich-enzyme immunoassays. In Pt-HD, although the plasma ET-3 or big ET-1 levels did not significantly correlate with blood pressure (BP), plasma ET-1 levels significantly (p less than 0.01) correlated with both the levels of systolic (r = 0.63) and diastolic (r = 0.54) BP. After 4-hour HD, the plasma level of ET-3, but not ET-1 or big ET-1, was significantly elevated and BP was significantly lowered. The present findings indicate that ET-1 and ET-3 play different roles in acute and chronic alterations of BP in Pt-HD.

[A case of transverse myelopathy caused by acupuncture]

A 54-year-old man received insertion of an acupuncture needle into the region extending from the posterior neck to the back on two occasions for the treatment of shoulder stiffness. Two weeks after the second acupuncture, he developed fever, dysarthria and mictionary disturbance, finally reaching the condition of tetraplegia. He was immediately admitted to an emergency room in our hospital, and was diagnosed as sepsis with DIC, ARDS, heart failure, renal failure, liver failure, and myelitis. After one month, he recovered with transverse myelopathy as a residual deficit. Neurological findings showed transverse myelopathy below the level of Th2 at that time. Cervical CT revealed an irregular low density at the periphery of the cervical vertebra from the C2 to C4 level. Cervical MRI revealed an irregular swelling of his spinal cord from the C2 to C7 level. We explained the mechanism of transverse myelopathy in this case as follows. After the acupuncture, he suffered a focal infection of the region of needle insertion, and then the infection expanded to the cervical vertebra, thus causing osteomyelitis, sepsis, and finally cervical myelitis. Direct injury of the spinal cord and nerve roots as a complication of acupuncture was previously reported, but indirect injury of the spinal cord due to myelitis had not been reported except our present case. Careful attentions should be paid to the complications of acupuncture.

Cardiorespiratory responses to standing arm ergometry in patients with ischemic heart disease. Comparison with the results of treadmill exercise

To compare cardiorespiratory responses to standing arm ergometry and treadmill exercise, two graded exercise stress tests were performed in 30 patients with ischemic heart disease (IHD). Cardiac catheterization and expired gas analyses were also done. Standing arm ergometry was discontinued because of arm fatigue in 15 (50%) patients, whereas treadmill exercise was stopped due to leg fatigue in 8 (27%) patients. Maximal increase in rate-pressure product and oxygen uptake, and magnitude of ST-segment depression during standing arm ergometry were significantly smaller (p less than 0.01, p less than 0.01 and p less than 0.05, respectively) than those during treadmill exercise. Furthermore correlations of maximal change in rate-pressure product, oxygen uptake and extent of ST-segment depression were not close between the two exercise tests (r = 0.76, r = 0.67 and r = 0.54, respectively). Our results indicate that the ability to detect IHD with standing arm ergometry is lower than that with treadmill exercise and that it is not possible to predict accurately one's capacity for arm exercise from the treadmill exercise test.

Plasma concentrations of endothelin-1 and endothelin-3 are altered differently in various pathophysiological conditions in humans

Several studies have indicated that endothelin-1 (ET-1) and endothelin-3 (ET-3) are produced by different cells. Although ET-1 is produced by vascular endothelial cells, these cells do not produce ET-3. In the present study, we measured plasma concentrations of both ET-1 and ET-3 by sandwich-enzyme immunoassays which we developed recently in patients on chronic hemodialysis, age-matched normal subjects, patients with acute myocardial infarction, patients undergoing surgery, and healthy subjects before and after strenuous endurance exercise. Plasma levels of ET-1 and ET-3 were demonstrated to be altered differently in the above conditions in humans. Although the exact origin of circulating endothelins has yet to be elucidated, the different alterations of plasma levels suggest that both ET-1 and ET-3 may play different roles in physiological and/or pathophysiological responses to various conditions in humans.