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Biomedical subjects

S Kaplan

Publications and source records attributed to S Kaplan.

At least 469 records · Page 26Linked to original sources
PubMed1976

Maximal exercise stress testing in normal and hyperlipidemic children.

Electrocardiographic and cardiovascular responses during maximal exercise were evaluated in 103 normal children and in 82 children with familial hyperlipoproteinemia. The normal and hyperlipidemic children were comparable in regards to age, weight--height index, resting and exercise blood pressures, and maximal working capacity indices. The cohort of 82 hyperlipidemic children included 61 children (29 boys and 32 girls) with well defined "monogenic" familial hyperlipoproteinemia. Segmental ST depression on the exercise electrocardiogram occurred in 8 of these 29 boys (27.6%) as compared to 4 of 55 normal boys (7.3%), P less than 0.025 and in 6 of the 32 girls (19%) as compared to 7 of 48 normal girls (14.6%), P greater than 0.1. Segmental ST depression was present in 14 of 61 (23%) children with "monogenic" hyperlipoproteinemia, as compared to 11 of 103 (10.75%) normal (x2 = 4.47, P less than 0.05). An assessment of the clinical significance of an abnormal exercise electrocardiogram in male children with "monogenic" hyperlipoproteinemia must await the following: (1) two to four decades of observation and study of the development of morbid or mortal coronary disease, or (2) the future development of improved invasive or noninvasive techniques for the early detection of covert coronary occlusive disease. Currently, maximal exercise electrocardiography cannot be contemplated as a useful indicator of eventual premature coronary artery disease in asymptomatic hyperlipidemic children.

Adolescent↗
PubMed1976

Pharmacological evidence for stimulation of growth hormone secretion by a central noradrenergic system in dogs.

The role of brain catecholamines in the regulation of growth hormone secretion was investigated in pentobarbital-anesthetized dogs by using drugs which modify the function of adrenergic neurons and receptors. Intravenous administration of L-dopa produced a prompt, statistically significant increase in plasma growth hormone concentration. This response was not significantly reduced by blockade of peripheral dopa decarboxylase activity with carbidopa. Clonidine, an alpha-agonist which penetrates the brain, increased plasma growth hormone secretion. Norepinephrine, epinephrine, dopamine and isoproterenol, catecholamines which do not penetrate the blood-brain barrier, failed to affect plasma growth hormone concentration when administered intravenously. Apomorphine did not produce a statistically significant increase in plasma growth hormone concentration when administered directly into the the third ventricle, and pimozide failed to abolish the increase in plasma growth hormone produced by L-dopa. The increase in plasma growth hormone concentration produced by intravenous L-dopa and clonidine was prevented by administration of phentolamine or phenoxybenzamine directly into the third ventricle. The response to L-dopa was also abolished by intraventricular procaine. In dogs in which central beta-adrenergic blockade was produced by intraventricular L-propranolol, the growth hormone response to L-dopa was greater than it was in control dogs treated with intraventricular D-propranolol. The data indicate that in pentobarbital anesthetized dogs, the increase in growth hormone secretion produced by L-dopa is mediated by norepinephrine, rather than dopamine, that the site of action of the norepinephrine is central, above the median eminence and inside the 'blood-brain barrier', and that the norepinephrine acts via alpha-adrenergic receptors.

Adrenergic alpha-Antagonists↗
PubMed1976

The impact of methadone and drug-free treatment on criminal behavior.

The present study was initiated to evaluate the effect of methadone versus drug-free treatment on a series of criminal involvement measures. A 50% random sample of the 776 clients who had registered with the Central Intake Unit over a one year period was selected for intensive study. Data were collected through examination of intake and treatment files for pre- and post-admission time periods. Arrest, conviction and incarceration rates as well as correctional status were measured and compared across pre-treatment, intake and three month post-intake periods. The arrest rate for the total sample decreased radically from 92.8% upon entering treatment to 8% after three months in treatment. The subsequent rates at 6, 9 and 12 months decreased in a fairly consistent manner. This trend was similar in the methadone, drug-free, and methadone/drug-free groups for either arrests, convictions or incarceration rates with time in treatment. The relationship between arrests and employment and drug use was also examined. No association was found between use of opiates as measured by urinalysis results and frequency of arrest. Similarly, arrest rates showed no significant association with employment rates during the first nine months of treatment, although the comparison at twelve months was significant with only 16.7% of those employed clients being arrested.

Adult↗
PubMed1976

Cardiac performance and oxygen consumption during intracardiac operations in children.

Cardiac performance and oxygen consumption in 30 patients undergoing surgical treatment for congenital cardiac disease were determined from intraoperative measurements. Arterial pressure, cardiac index, mean left ventricular hydraulic output power, pulmonary artery oxygen saturation were obtained at average mean left atrial pressures of 8.1 and 15.2 cm H2O after cardiopulmonary bypass in 20 patients. These same variables were measured at an average pulmonary artery saturation of 65 and 75% in 30 patients. A composite of measurements of cardiac performance was desirable to guide precise patient care intraoperatively, especially if myocardial function was compromised. It is suggested that left atrial pressure be maintained at a level that results in a pulmonary artery saturation greater than 65%.

Adolescent↗
PubMed1976

Separation of inner and outer membranes of Rhodopseudomonas spheroides.

The separation of inner and outer membrane of Rhodopseudomonas spheroides has been achieved by means of sucrose density gradient (20%, 40%, 60%, w/w) centrifugation. The upper fraction of the gradient, with a specific density 1.181 (g/cm3), is high in cytochrome and succinate dehydrogenase activities, low in lipopolysaccharides and it is designated the inner membrane fraction. The bottom fraction of the gradient, with a specific density 1.240, is high in lipopolysaccharide and contains neither cytochrome nor succinate dehydrogenase activities. This fraction is the cell wall or outer membrane fraction. The intermediate band on the gradient is an unseparated fraction of inner and outer membrane fragments. This fraction has a specific denisty of 1.211 and represents less than 3% of total crude envelope. Thin sections of the vesicles of the inner membrane fraction and those of outer membrane provide morphological evidence for the identity of the individual membrane fractions. At least 22 protein bands are resolved by employing sodium dodecyl sulfate slab gel electrophoresis. Six bands are present only in the inner membrane and two bands are found exclusively in the outer membrane. Most of the remaining polypeptides are present in greater amounts in the inner membrane relative to the outer membrane fractions.

Bacterial Proteins↗
PubMed1976

Pediatric-psychiatric liaison as a model for teaching pediatric residents.

The pediatrician's function as a comprehensive family health practitioner has frequently been ignored. A major problem is that pediatric residents are not trained or are inadequately trained to assess emotional, behavioral, and family problems that may be an integral part of the patient's symptoms. At the Children's Hospital of Philadelphia, a pediatric-psychiatric liaison program has evolved in which pediatric residents learn the principles and skills necessary to manage these problems. Ultimately, the liaison program will enable the staff pediatricians who use these principles to assume appropriate responsibility for educating the pediatric trainees.

Child Psychiatry↗
PubMed1976

Mitral and tricuspid valve closure in congenital heart disease.

Echocardiography was used to evaluate mitral and tricuspid valve closure in patients 1 day to 20 years of age. When possible, simultaneous phonocardiograms were obtained. The difference in time between the Q wave of the electrocardiogram and mitral closure and between Q and tricuspid closure was designated the delta value. Four groups of patients were assessed: 1) normals (40), secundum atrial septal defect (ASD) (10), mitral valve prolapse syndrome (Barlow's syndrome) (13), pulmonary hypertension (12), and pulmonic stenosis (6); 2) Ebstein's anomaly (10); 3) transposition of the great vessels (15); 4) right bundle branch block (RBBB) (25). Ten patients with surgically induced right bundle branch block were studied by phonocardiography alone. Group I had values of 50 msec or less (-5 to 50 milliseconds) and served as controls. Ebstein's anomaly showed prolongation of the delta value to 65 msec or greater in eight out of ten patients. Patients with transposition of the great vessels showed a striking difference from the preceding groups in that an average negative delta value was obtained. Twenty-two patients of group 4 (RBBB) had delta values within the normal range. This study has shown that a delta value greater than 65 msec is suggestive of Ebstein's anomaly. In addition, if the delta value is negative, transposition of the great vessels can be suspected.

Adolescent↗
PubMed1976

Nitroprusside after open-heart surgery.

The effects of intravenous infusion of sodium nitroprusside were studied in 11 children immediately after open-heart surgery for congenital heart disease. The patients were selected because, following bypass, their cardiac index was below 2,0 L/min/m2 and their systemic vascular resistance exceeded 30 units. In order to eliminate the effects of preload, mean left atrial pressure was maintained at a constant level by blood transfusion. During infusion of nitroprusside the mean decrease of mean arterial pressure was 18.6%, of systemic vascular resistance was 53.7%, and the increase in cardiac index was 76.9%. All children recovered.

Blood Pressure↗
PubMed1976

Response to exercise in patients after total surgical correction of Tetralogy of Fallot.

Heart rate, blood pressure, physical working capacity, and electrocardiographic changes were evaluated during upright bicycle exercise in 43 asymptomatic patients, aged seven to 41 years, one to 14 years after total surgical correction of tetralogy of Fallot (TF). One hundred and nine normal subjects between the ages of five and 42 years served as controls. The patient and control groups, subdivided by sex and body surface area (BSA), were similar in height and weight. When comparing males to males and females to females with BSA greater than or equal to 1.2 m2, maximal heart rates and working capacities were lower in the patient groups than in the control groups. An inverse relationship was observed between maximal working capacity and age at surgery in both male and female patient groups. By contrast, especially in the males with BSA less than 1.2 m2, the mean maximal heart rates and working capacities did not differ significantly between the patient and control groups. Premature atrial or ventricular contractions were recorded in ten of 43 patients (23%) after exercise. Five of these ten patients had multifocal premature ventricular contractions (PVC) and four had unifocal PVC. In the five patients with multifocal PVC, a short burst of ventricular tachycardia occurred in two, coupling in one, and bigeminal rhythm in two. Cardiac arrhythmia was not observed in the control group. Although our current surgical results are excellent, this study suggests that impaired cardiovascular function persists after corrective surgery and that early surgical treatment may be more desirable. Furthermore, additional data suggest that the exercise procedure may be useful in detecting and managing patients who may develop life-threatening arrhythmias following intraventricular surgery.

Adolescent↗
PubMed1976

The isovolumic contraction time of the left ventricle. An echographic study.

The echographic isovolumic contraction time (ICT) of the left ventricle (LV) was measured in order to assess alterations of LV performance in children with various forms of cardiac disease. The echographic ICT was defined as the interval between coaptation of the anterior and posterior mitral valve leaflets and aortic cusp opening. Four groups of patients were evaluated: normal (48); LV myocardial disease (20); patent ductus arterosus (PDA) (19); and aortic stenosis (AS) (15). In normal children ICT shortened with decreasing age and increasing heart rate. Isovolumic contraction time was more influenced by heart rate (HR) than age, but the relationship was still weak (r = 0.61). In patients with LV myocardial disease ICT was markedly prolonged, while in children with patent ductus arteriosus and aortic stenosis it was shortened as compared with normal children (P less than 0.01).

Adolescent↗
PubMed1976

Evidence that blood pressure controls heart rate in the chick embryo prior to neural control.

Blood pressure increases will increase heart rate in intact chick embryos, prior to the development of neural control. Similarly, in surgically isolated hearts, increases in intraventricular fluid pressure will increase the rate of beat. However, fluid pressure applied equally to both interior and exterior surfaces of the isolated heart does not result in increased heart rate. Therefore, we conclude that the increased pressure stretches the heart muscle and that this stretch stimulates the increased heart rate. While heart rate is clearly influenced by blood pressure, the reverse is not true. Propranolol reduces the heart rate to about half normal in intact embryos but does not significantly alter the blood pressure.

Animals↗
PubMed1976

Echocardiographic evaluation of adriamycin cardiotoxicity in children.

Thirty children with malignant solid tumors receiving adriamycin had serial evaluation of left ventricular (LV) function by echocardiography. The echocardiographic studies showed a progressive decrease in myocardial contractility as evidenced by changes in several parameters of LV function with increasing cumulative doses of the drug. Using the patients as their own controls, serial echocardiography appears to be a reliable method for detecting early alteration of cardiac function in the asymptomatic patient. This technique may prove useful to prevent cardiomyopathy secondary to adriamycin and to prolong therapy beyond the currently established limits.

Adult↗
PubMed1975

Cardiac catheterization and selective angiography in infants with a new flow-directed catheter.

Preliminary experience with a new flow-directed pediatric angiography catheter in 35 infants indicates that catheterization of all cardiac chambers and both great vessels can be accomplished without risk of perforation or major arrhythmia. Antegrade access to the aorta from the left ventricle via the foramen ovale reduced the need for retrograde arterial catheterization. The maneuverability of this balloon-tipped catheter coupled with the ability to perform safely selective angiography at any site entered establishes a unique advantage over standard cardiac catheters now in use. The success with this catheter in performing right and left heart studies and the safety in its use promise to significantly reduce the risk of mechanical and angiographic accidents during the intracardiac investigation of critically ill infants with congenital heart disease.

Angiocardiography↗