Coefficients in the CAVI Equation and the Comparison Between CAVI With and Without the Coefficients Using Clinical Data

Aim: The Cardio-Ankle Vascular Index (CAVI) is a stiffness index of the arterial tree from the origin of the aorta to the ankle, independent of blood pressure at the time of measurement. The CAVI equation includes the coefficients “a” and “b” to adjust it to the value of Hasegawa's pulse wave velocity, which is compensated for at 80 mmHg of diastolic pressure. To verify this adjustment with the coefficients, the clinical significance of CAVI and CAVI without the coefficients (haβ) were compared in both an epidemiological study and an acute clinical study.

Methods: In the epidemiological study, the significances of CAVI and haβ among people with or without coronary risks such as hypertension, dyslipidemia, hyperglycemia, and abnormal electrocardiography change, were compared. In the acute clinical study, nitroglycerin was administered to subjects in a control group and to coronary artery disease patients, observing CAVI and haβ values over a 20-min period.

Results: There was no discrepancy in terms of statistically significant differences between CAVI and haβ among subjects with or without risk factors. Furthermore, there was also no discrepancy in terms of statistically significant differences between CAVI and haβ during the changes of those values following nitroglycerin administration over a 20-min period.

Conclusion: In both the epidemiologic and clinical studies, there was no discrepancy in terms of significant differences between CAVI and haβ. These results suggest that both are valid as indices of stiffness of the arterial tree from the origin of the aorta to the ankle.

Laser induced injury caused hyperglycemia-like effect in Drosophila larva: a possible insect model for posttraumatic diabetes

Diabetic patients need particular care in case of infection, digestive disorder or external injury, because external stress often exasperates the glucose metabolism, which is known as “sick day management”. In addition, severe trauma can be a cause of hyperglycemia with insulin resistance. In spite of critical component of the treatment, the precise mechanisms of how trauma develops posttraumatic diabetes remain unknown. Here, we ablated body wall muscles in Drosophila larvae by laser beam and found that the level of trehalose, the principal sugar circulating in the hemolymph or in the tissues of most insects, was increased. The model may provide a helpful tool to understand the relationship between trauma and sugar metabolism.

Inhibition of rat vascular smooth muscle proliferation in vitro and in vivo by bone morphogenetic protein-2

Vascular proliferative disorders are characterized by the proliferation of vascular smooth muscle cells (SMCs) and excessive extracellular matrix synthesis. We found that bone morphogenetic protein-2 (BMP-2) inhibited serum-stimulated increases in DNA synthesis and cell number of cultured rat arterial SMCs in a fashion quite different from that in the case of transforming growth factor-beta1 (TGF-beta1). In addition, TGF-beta1 stimulated collagen synthesis in SMCs, whereas BMP-2 did not. In an in vivo rat carotid artery balloon injury model, the adenovirus-mediated transfer of the BMP-2 gene inhibited injury-induced intimal hyperplasia. These results indicate that BMP-2 has the ability to inhibit SMC proliferation without stimulating extracellular matrix synthesis, and suggest the possibility of therapeutic application of BMP-2 for the prevention of vascular proliferative disorders.

Effect of long-term cyclic mechanical load on protein synthesis and morphological changes in cultured myocardial cells from neonatal rat

We studied the effect of prolonged cyclic mechanical stimulation on protein synthesis and morphological changes in cultured cardiac myocytes isolated from 3-day-old neonatal rats to develop an in vitro model for cardiac hypertrophy induced by a mechanical load. Myocardial cells were cultured on deformative culture plates with M-199 culture medium in the presence or absence of fetal calf serum (FCS), and a cyclic mechanical load was applied for 2 hours up to 15 days. Mechanical stimulation for 2 hours increased the 14C-phenylalanine incorporation rate of myocardial cells, both in the absence and presence of FCS or when the myocardial cells were either beating or arrested with tetrodotoxin. The incorporation rate always increased by mechanical stimulation during 15 days of cell culture as compared to cells that sustained no mechanical stress. The cell size and protein content, which increased gradually with mechanical stimulation and reached a maximum at 10 days, were even greater in the presence of FCS. Within 10 days myocardial cells had aligned in the direction of the maximal cyclic mechanical load. In these cells electron microscopy revealed an increase in the number of myofilaments associated with the development of mitochondria as recognized in the adult myocardial cells. These results indicate that long-term cyclic mechanical loading of cultured myocardial cells may be a good in vitro model for the study of cardiac hypertrophy.

High incidence of mitral and tricuspid regurgitation in patients with Graves' disease detected by two-dimensional color Doppler echocardiography

With two-dimensional (2D) color Doppler echocardiography, the cardiac and valvular function of 24 consecutive patients with a history of Graves' disease (17 were hyperthyroid and 7 were euthyroid at the time of the examination) were evaluated. The incidences of mitral regurgitation (MR), tricuspid regurgitation (TR) and MR plus TR were significantly higher in the patients with Graves' disease than in the age-matched control group of patients without this disease. In the patients who had signs of congestive heart failure (CHF) while they were hyperthyroid, a significantly higher incidence of severe TR was observed. This is the first report of a 2D color Doppler echocardiography study on the incidences of TR and/or MR in patients with Graves' disease. Our data indicate that in Graves' disease valvular dysfunction can be caused by systemic disorders and that severe TR is a possible risk factor for CHF.

Pathological analysis of the right ventricular hypertrophy and ventricular interdependence in autopsied hearts with cor pulmonale and pulmonary hypertensive rat hearts

Thirty autopsied hearts with cor pulmonale and 20 experimental pulmonary hypertensive rat hearts were analysed macroscopically and histometrically. In autopsied hearts with cor pulmonale, right ventricle dilatated in oblique length, and right ventricular wall thickness significantly increased at pulmonary conus (PC) and posterior wall of right ventricle (RVP) compared with that at anterior wall of right ventricle (RVA). Mean diameters of myocardial fibers at PC, RVP, right ventricular side of interventricular septum (IVR) and mid layer of interventricular septum (IVM) significantly increased compared with that at mid layer of left ventricular wall (LVM). The wet weight and the diameter of myocardial fibers in right ventricle (RV) significantly correlated with those in interventricular septum (IVS). In pulmonary hypertensive rats, wet weights of RV and IVS increased significantly with the elevation of mean pulmonary arterial pressure. The diameters of myocardial fibers increased at RVP, RVA, IVR and IVM. There was no significant cardiac hypertrophy in left ventricle (LV), either microscopically or macroscopically. These results suggest that IVS responded morphometrically rather than in concord with RV but not with LV in the cor pulmonale heart.

Risk factors for the complication of cerebral infarction in Japanese patients with acute myocardial infarction

The incidence and risk factors for cerebral infarction in Japanese patients with acute myocardial infarction were evaluated. Seven (5.0%) of 140 patients with acute myocardial infarction suffered from cerebral infarction during their initial hospitalization. The incidence was slightly higher than those reported in Western countries. Anterior wall myocardial infarction and a past history of cerebrovascular disease were considered to be probable risk factors for the complication. A beneficial effect of anticoagulant therapy in preventing cerebral infarction in cases of acute myocardial infarction with those risk factors is suggested.

Mechanisms for improvement of cardiac performance by nifedipine in an acute mitral regurgitation in dogs

To elucidate the mechanisms of the beneficial hemodynamic action of nifedipine in congestive heart failure, the systolic and diastolic hemodynamic parameters were evaluated for 30 min after sublingual administration of 20 mg of nifedipine in 12 dogs with acute mitral regurgitation (group 1) and in 5 dogs without mitral regurgitation (group 2, sham operation group). An additional 6 dogs with mitral regurgitation were followed for 30 min without nifedipine (group 3). Nifedipine lowered both arterial pressure and systemic vascular resistance, increased coronary blood flow and stroke volume significantly in both groups 1 and 2. The left ventricular developed tension was increased by nifedipine only in group 1, probably due to the geometric changes in the expanded left ventricle in failure, secondary to left ventricular preload and afterload reduction. Nifedipine had no effects on ventricular relaxation properties in this study. This study suggests that the mechanisms responsible for the improvement of cardiac performance induced by nifedipine in heart failure caused by an acute mitral regurgitation are essentially a reduction in left ventricular afterload and an increase in left ventricular contractility secondary to afterload reduction.

Ambulatory electrocardiograms obtained by Holter monitoring system in patients with permanent demand pacemakers

Ventricular inhibited demand pacemakers (VVI) were implanted in 27 patients with complete A-V block and pacemaker arrhythmias were analyzed by Holter system ambulatory electrocardiograms and conventional electrocardiograms. With Holter ECG, 13 patients showed myopotential inhibition, 5 patients had sensing failure and premature ventricular contractions (PVC) were observed in all patients. On the contrary, myopotential inhibition and sensing failure were not detected by conventional ECG and the detection rate of PVC was only 30%. The transient recovery of A-V conduction was observed in 14 of 27 patients with Holter ECG, but was not detected by conventional ECG. The Holter system ambulatory electrocardiogram clearly demonstrated the complex cardiac arrhythmias. Therefore, it is useful for monitoring arrhythmias caused by VVI pacemakers.

[Mitral valve prolapse in patients with anorexia nervosa]

Mitral valve prolapse (MVP) is frequently observed in patients with low body weight and/or skeletal abnormalities such as pectus excavatum and straight spines. There may be a variety of associated autonomic dysfunctions. Whether MVP is a complication of anorexia nervosa which has similar clinical features, including weight loss, skeletal abnormalities and autonomic dysfunctions, has not been reported. The present study was an investigation of the incidence of MVP and cardiac function in anorexia nervosa by echocardiography. Two-dimensional and M-mode echocardiography, and systolic time intervals were evaluated for 19 women with anorexia nervosa, from 13 to 25 years of age and having a mean age of 18.2 years. Their body weights ranged from 23.9 to 43 kg with a mean of 33.5 kg, and were at least 25% less than their ideal body weights (ranges were from 25 to 52%). The same studies were performed for 19 women with MVP diagnosed echocardiographically and without anorexia nervosa as controls. Their ages ranged from 14 to 26 years. Results were as follows: MVP was observed in 74% of patients with anorexia nervosa. The mean heart rates were 51.7 and 70.5/min in the anorexia nervosa and control groups, respectively. A significant difference (p less than 0.001) was observed between the two groups. The mean heart rate of patients with anorexia nervosa having MVP of both leaflets and no MVP were 45.8 and 59.0/min, respectively. The difference between these two sub-groups was statistically significant (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Medical treatment of infective endocarditis and its limitations

In an attempt to establish an appropriate management program for patients with active infective endocarditis, 30 patients treated during the past 20 years were studied retrospectively. Microorganisms were confirmed in 27 of the 30 patients (90%) (86.7% by culture and 3.3% at surgery). Among these 27 patients, viridans streptococci were confirmed in 23 (85.2%), aureus staphylococci in 2 (7.4%), epidermidis staphylococci in one (3.7%) and candida albicans in one (3.7%). Twenty of the 23 patients (87%) with viridans streptococcal endocarditis were treated medically with good success, but 2 patients (8.7%), who developed severe congestive heart failure (NYHA 3-4 degrees), underwent emergency surgery, and one of them (4.3%) died from severe heart failure. The synergistic effects of the combined antibiotic therapy were not ascertained in the present series. It was noteworthy that a bolus intravenous administration of penicillin was more effective than its continuous drip infusion. Both patients with aureus staphylococcal endocarditis died before surgery. One patient with prosthetic valve endocarditis due to candida died after a second operation. It is concluded that most patients with active infective endocarditis can be medically treated successfully, but surgery should be performed urgently for patients with severe heart failure, poor response to antibiotics, aureus staphylococcal and candida endocarditis and prosthetic valve endocarditis.

Prinzmetal's variant angina induced only by alcohol ingestion

Prinzmetal's variant agina occurred in a 52-year-old man 10-11 h after the ingestion of alcohol, when blood levels of alcohol decreased almost to the zero level. Coronary arteriograms revealed significant narrowing in the left circumflex artery and the left anterior descending artery and minimal wall irregularity in the right coronary artery; however, both exercise and pharmacologic stress tests were negative. A withdrawal from an acute exposure to alcohol was discussed as a possible causative mechanism of the alcohol-induced Prinzmetal's variant angina in this case.

Hemodynamic effects of nifedipine in congestive heart failure

Nifedipine, a potent coronary vasodilator, was administered in a single sublingual dose of 20 mg to eight patients with mild to moderate congestive heart failure. Nifedipine produced a slight increase in heart rate (mean +/- standard error of the mean 73.3 +/- 3.2 versus 80.9 +/- 2.1 beats/min, p < 0.025) and an increase in cardiac index (from a control value of 3.51 +/- 0.22 to 4.06 +/- 0.31 liters/min per m2, p < 0.01). Arterial blood pressure decreased from 112.9 +/- 6.2/67.7 +/- 4.2 (mean 84.9 +/- 4.0) to 100.8 +/- 4.4/56.4 +/- 11.0 (mean 76.1 +/- 4.3) mm Hg (p < 0.01) and total systemic vascular resistance also decreased from a control value of 15.6 +/- 1.0 to 12.4 +/- 0.8 units (p < 0.01) after administration of nifedipine. These data suggest that nifedipine may be useful for vasodilation in congestive heart failure.

Some observations on serum concentrations of digitoxin and digoxin

Serum concentrations of digitoxin and digoxin were measured in 145 cases with various heart diseases receiving maintenance doses of digitalis. Digitalis toxicity was seen in only 2 cases (1.4%). Day-to-day variation of serum concentration while taking the same daily dose was small in digitoxin therapy (13.8%), but a considerable variation was seen in digoxin therapy (24.4%). Serum concentrations of both digitoxin and digoxin were measured in the patients receiving digitoxin, and there was a positive correlation between the two (r = 0.66, p less than 0.001). This fact suggested that the effect of digitoxin was the sum of the effects of digitoxin and its metabolite, digoxin. In the patients taking digoxin, digitoxin was not detected in the serum. Serum digitoxin level had a significantly positive correlation to serum albumin level, presumably because digitoxin was retained in serum in the bound form to albumin. Minimal effective level, 10 ng/ml, was however obtained with higher daily dose of digitoxin in patients with lower serum albumin.