High sensitivity of chicken's skeletal muscle sarcoplasmatic reticulum to effects of diltiazem or verapamil on calcium uptake and release.

In this study, the effects of two different calcium channel blockers, diltiazem and verapamil on calcium uptake and release from the membrane of heavy sarcoplasmic reticulum (SR) of chicken skeletal muscle were investigated. A fluorescent chelate probe technique was employed to determine calcium movement through the SR. Chlortetracycline was used as a fluorescent indicator which is able to penetrate the membrane, bind to the calcium on the inner face of the membrane and show an increase in fluorescence intensity when calcium uptake occurs. Addition of tris-ATP to the microsomes caused ATP-induced calcium uptake in a concentration dependent manner with half-maximal calcium uptake around 0.126 mM. Pretreatment of the medium containing sarcoplasmic reticulum with different concentrations of diltiazem or verapamil followed by added tris-ATP resulted a significant decrease in the fluorescence intensity of chlortetracycline, showing that these calcium channel blockers can diminish ATP-induced calcium uptake in a concentration-dependent manner. The maximum fluorescence intensity of tris-ATP falls to 50% in the presence of 1.75 microM diltiazem and 25 nM verapamil. In addition, diltiazem and verapamil can significantly induce rapid calcium release from the membrane of sarcoplasmic reticulum in a concentration-dependent manner. Therefore, membrane-bound or sequestered calcium in the sarcoplasmic reticulum may be targeted by these two calcium channel blockers in chicken skeletal muscle. Chicken SR is about 1000 times more sensitive to the effects of diltiazem on Ca2+ uptake and release than rabbit SR as shown previously.

Regression of pulmonary hypertension after mitral valve surgery in children. Operative management of rheumatic mitral valve disease.

Forty-one children with advanced chronic rheumatic disease of the mitral valve had preoperative and postoperative hemodynamic studies. Twenty-three cases had open mitral commissurotomy, and 20 had mitral valvular replacement. After surgery the average pulmonary arterial systolic pressure in the group with valve replacement decreased from 78 to 42 mm Hg, the pulmonary vascular resistance decreased from 974 to 313 dynes sec cm 5, and the cardiac index rose from 2.29 to 4.15 L/min sq m. In the group with mitral commissurotomy, the average pulmonary arterial systolic pressure decreased from 90 to 63 mm Hg, the pulmonary vascular resistance decreased from 1,201 to 616 dynes sec cm-5, and the cardiac index rose from 2.5 to 3.5 L/min sq m. While all patients with mitral valve replacement showed a drop in pulmonary arterial pressure, the postoperative pressures were higher after commissurotomy in four patients, two of whom required a second operation of valve replacement. The study shows that in children, even severe degrees of pulmonary hypertension secondary to mitral valve abnormality is corrected.

Modern management of the diabetic pregnancy.

The effect of modern antepartum and intrapartum fetal monitoring technics on the outcome of the pregnancy complicated with diabetes was studied by comparing the perinatal mortality of 2 groups of patients whose management differed primarily by the use of these tests. The perinatal death rate was halved to 9.2%, and when corrected for major congenital defects and referred fetal deaths it was 5.3%. Modern fetal diagnostic tests clearly add a degree of objectivity in the management of the diabetic pregnancy not previously available.

Modern management of hypertensive disorders of pregnancy.

Hypertensive disorders of pregnancy contribute significantly to perinatal mortality. Successful application of modern tests of antepartum fetal status and appropriately timed delivery, with monitored labor and liberal use of cesarean section led to significantly improved fetal and neonatal salvage in 242 patients with hypertensive disorders of pregnancy between 1973 and 1975. The reduction in perinatal mortality to a corrected rate of 12/1000 in the years 1973-1975, compared to a previous rate of 75/1000 between 1970 and 1972, justifies the modern aggressive management of hypertensive disorders in pregnancy.

Rupture of the uterus.

Sixty-four cases of rupture of the uterus were managed from March 1967 to March 1977. The maternal morbidity was 81.0%, and there were six maternal deaths (9.4%). Fifty-two patients (85.5%) had hysterectomies. The average hospital stay for patients who survived was 15.5 days. The fetal mortality rate was 89%. The etiology, diagnostic evaluation and the mode of prevention are discussed.

Enhanced BaZrO3 mechanosynthesis by the use of metastable ZrO2 precursors.

The current work assesses the impact of structural differences between stable and metastable ZrO2 precursors on the mechanochemical preparation of BaZrO3. Monoclinic (m-ZrO2) and tetragonal (t-ZrO2) zirconia polymorphs were prepared without stabilizing additives by slow alkaline precipitation. High-energy milling of the individual ZrO2 precursors induced different partial transformations in each case. The as-synthesized m-ZrO2 powders showed partial conversion to the tetragonal polymorph on mechanical activation, reaching about 10% t-ZrO2 after 420 min accompanied by increases in strain. In contrast, the as synthesized t-ZrO2 powders underwent the inverse transformation to the monoclinic phase, producing about 50% m-ZrO2 after 120 min with the liberation of strain. The t-ZrO2 precursor was shown to exhibit the higher reactivity with barium peroxide, yielding significantly earlier formation of barium zirconate under room-temperature mechanosynthesis. The progress of the mechanochemical formation of BaZrO3 has been discussed with respect to the differing behaviour of the ZrO2 precursors upon mechanical activation and associated thermodynamic perspectives.

Effect of morphine on the reduced uteroplacental perfusion model of pre-eclampsia in rats.

OBJECTIVES: To investigate the effect of morphine on the reduced uteroplacental perfusion pressure (RUPP) model of pre-eclampsia in rats. STUDY DESIGN: The abdominal aorta and ovarian arteries of pregnant rats were isolated and clipped on gestational day 14. The chronic morphine treatment group received naltrexone 5 mg/kg 1h before each dose of morphine. L-nitromonomethylarginine 2 mg/kg was administrated in the same pattern. The control group received saline 10 ml/kg. Systolic blood pressure, blood urea nitrogen (BUN), creatinine, creatinine clearance, urinary protein, urinary nitrite/nitrate excretion, and fetal and placental weights were determined. RESULTS: Morphine significantly reduced systolic blood pressure, fetal and placental weights, plasma BUN, creatinine and urinary protein in RUPP rats compared with control rats. Urinary nitrite/nitrate excretion and creatinine clearance were significantly increased in response to morphine treatment. CONCLUSION: Morphine reduced blood pressure and improved renal function in the RUPP model of pre-eclampsia, but this was associated with reduced fetal and placental weights.

Prediction of pulmonary arterial pressures from electrovectorcardiographic data in pediatric patients with rheumatic mitral valve disease.

The Frank vectorcardiogram (VCG) and the electrocardiogram (ECG) were used to predict pulmonary arterial pressures in 30 pediatric patients with rheumatic mitral valve disease. The patients' ages ranged from eight to 14 1/2 years. Eleven were male and 19 were female. Sixteen had mitral stenosis, eight had mitral regurgitation and six had mitral stenosis and regurgitation. Mean pulmonary arterial wedge pressure ranged from 5-32 mmHg. All patients underwent complete catheterization and angiocardiographic study. None had significant gradient across the right ventricular outflow tract. Right maximum spatial vector (Rmsv) was calculated using Frank VCG.R in V1 and S in V5 of ECG were also measured. Rmsv, RV1, and SV5 were correlated with pulmonary arterial pressures (systolic, diastolic and mean). Pulmonary artery systolic pressure and Rmsv bear the best correlation (r=0.773). The correlation coefficient for pulmonary artery diastolic pressure and Rmsv was 0.698. Rmsv as calculated from Frank VCG is useful in prediction of pulmonary arterial pressures (systolic and diastolic) in pediatric patients with rheumatic mitral valve disease.

Priorities of pediatric cardiology in the developed and developing countries.

Congenital heart disease and pediatric cardiology problems exist all over the world. The approach, however, including diagnosis and management varies considerably depending on manpower available, the clinical facility and the sociophilosophical climate prevailing in different parts of the world. In this article the priorities existing in the developed and developing countries concerning the approach to pediatric cardiology problems are discussed from the point of view of patient load, facilities available, teaching and research in this large field of highly specialized pediatric practice.

Antiarrhythmic effect of hypertonic sodium bicarbonate and sodium chloride in ouabain-induced arrhythmias.

Ouabain-induced tachyarrhythmias in cats can be abolished by bolus injection of NaHCO3 solution. This effect is consistent, rapid and of short duration. The antiarrhythmic effect appears to be due to high sodium concentration of this solution, as hypertonic NaCl solution with equal concentration of sodium exerts the same effect. Alkalinity and hyper-osmolality cannot account for the antiarrhythmic effect of NaHCO3 as respiratory alkalosis and mannitol solution with equal osmolality did not relieve the arrhythmias. Overdrive suppression is not responsible for this effect as the heart rate slows down during normalization of the cardiac rhythm. It is postulated that high Na+ concentration abolished ouabain-induced arrhythmias by competition with calcium ion in the myocardial cell sarcotubular system thus replacing it. This hypothesis is supported by the known effect of other agents such as sodium-EDTA and magnesium chloride, in digitalis-induced arrhythmias, which exert their antiarrhythmic properties by removal or displacement of calcium in the myocardial cells.

Isolated unilateral absence of the pulmonary artery. Review of the world literature and guidelines for surgical repair.

A 10-month-old boy is presented who had isolated unilateral absence of the right pulmonary artery. He suffered from hemoptysis and severe congestive heart failure. The patient underwent prosthetic anastomosis of the right to the main pulmonary artery. Although the hemodynamic response was favorable, his oxygenation did not improve due to diffuse pulmonary arteriovenous fistulae of the affected lung. The patient succumbed 3 months after operation due to massive uncontrollable hemoptysis from the right lung. Isolated unilateral absence of the pulmonary artery is a rare lesion. In our review of the world literature as of November 1976, 47 cases (including this report) of the unilateral absence of the pulmonary artery have been reported. Of these 25.5% had pulmonary hypertension and only 4 cases underwent successful repair of the lesion. Though repair of this defect can be carried out, the result may not be always gratifying. Our experience with this case has led us to consider a lung biopsy before proceeding to the surgical repair of the lesion. If the affected lung shows arteriovenous abnormalities the operation should not be recommended.

Simplified vectorcardiographic method for assessment of pulmonary arterial pressure in children with chronic rheumatic mitral valve disease.

We previously reported that pulmonary artery pressures can be assessed in children with chronic rheumatic mitral valve disease by measuring right maximum spatial vector from Frank vectorcardiogram. To simplify the calculation, pulmonary artery systolic pressure was correlated with maximum negative deflection on Frank scalar X-lead (SX), maximum negative deflection on scalar Z lead (SZ), sum total of SX and SZ (SX+SZ) and combined SX and SZ. The patient material consisted of 30 children with chronic rheumatic mitral valve disease, aged 8-14 1/2 years. Eleven were male and 19 were female. Sixteen had mitral stenosis, 8 had mitral regurgitation, and 6 had combined mitral regurgitation and stenosis, documented by cardiac catheterization and angiocardiographic study. The results showed a significant correlation between pulmonary artery systolic pressure and SX (r=0.782). As calculation of SX is considerably easier and less time consuming than that of right maximum spatial vector, this simplified method is preferable to right maximum spatial vector for prediction of the pulmonary artery systolic pressure of children with pulmonary hypertension due to chronic rheumatic mitral valve disease.

The vectorcardiogram as an aid to diagnosis in left ventricular-right atrial communication.

Frank vectorcardiograms (VCGs) in four patients with left ventricular-right atrial (LV-RA) communication were analyzed and compared with published values of VCGs of normal individuals and those from a group of patients with membranous ventricular septal defect. It was observed that the QRS-loops in the frontal and sagittal planes of the patients with LV-RA communication are shifted more superiorly than usual. Thus, almost 50% of the QRS-loop area was superior to the X- and Z-coordinates in the frontal and sagittal planes, whereas in the controls less than 10% of the frontal and sagittal plane QRS-loops were superior to the horizontal axes. The QRS-loops of patients with LV-RA communication thus seem to be halfway between normal and endocardial cushion defect loops. An unusual degree of superior orientation of the QRS-loop in a patient with clinical findings of a ventricular septal defect should arouse suspicion of a LV-RA communication. Also in patients with an isolated ventricular septal defect but with an exaggerated superior orientation of the QRS-loop in the frontal and sagittal planes, the interatrial septum should be examined at the time of operation to exclude the possibility of an associated LV-RA communication.

A morphometric study of the aortomitral valve apparatus in the embryonic and adult chicken heart. Implications on the developmental hypotheses of the transposition of the great arteries.

A comparative morphometric study was performed on the aortomitral valve apparatus of the embryonic and adult chicken hearts. It was found that the thickness of the aortic and mitral valve cusps diminishes dramatically as the embryo matures, however the relative length of the aortic valve, mitral valve and subaortic conus remains constant. A comparison of the aortomitral valve apparatus in chicken and man revealed that the subaortic conus is not completely resorbed in the fowl, whereas this process is well documented in the mammalian hearts. The implications of this observation on "the differential conal growth hypothesis" of transposition of the great arteries are discussed.

Pulmonary arteriovenous fistulas. Case presentations and clinical recognition.

This report describes characteristic features and clinical presentation of six young patients (ranging in age from five to 25 years) with various congenital forms of pulmonary arteriovenous fistulas as well as one 21-year old patient with traumatic intrapulmonary arteriovenous fistula. The former six patients were cyanotic, had clubbing of the digits and exertional dyspnea; two, additionally, had telangiectasia. All patients underwent cardiac catheterization and pulmonary angiography. None had pulmonary hypertension. Angiographically, four had diffuse arteriovenous fistulas in both lungs (Figures 1 and 3 to 5) and two had arteriovenous fistulas localized in one pulmonary segment. Four patients were additionally studied with radionuclide angiography and pulmonary perfusion scintigraphy. In three of these, substantial right-to-left shunt in the region of the lungs was detected; the diagnosis could not be established in only one of the latter with a small traumatic intrapulmonary arteriovenous shunt of less than 10%. While noninvasive methods provide adjunctive diagnostic support, pulmonary angiography is still required to assess, with certainty, the nature and localization of the lesion. In cyanotic patients with no evidence of cardiac disease, differential diagnostic consideration should be given to pulmonary arteriovenous fistulas.