Search PubMed⌕ Search

Biomedical subjects

S Subramanian

Publications and source records attributed to S Subramanian.

At least 325 records · Page 18Linked to original sources
PubMed1976

Coarctation of the aorta in children and adolescents. Surgical treatment and review of 120 patients.

Between September 1967 and April 1975, a total of 120 patients between one day and 20 years of age underwent surgery for coarctation of the thoracic aorta. Thirty-two patients were below two years of age (group 1) and 88 were above two years (group 3). All patients in group 1 initially had congestive heart failure. Twenty-eight had associated cardiac defects, and 18 had signficant pulmonary arterial hypertension (greater than 50 mm Hg). Operative deaths occurred only in group 1, all in infants below five months of age. Common features in the 13 deaths were congestive heart failure, pulmonary hypertension, patent ductus arteriosus, large ventricular septal defect, concomitant pulmonary arterial bandling or open-heart procedures. The only recurrence occurred in an infant first operated at 14 days of age. Resection of aortic coarctation can be safely performed as an elective procedure; however, it still presents a high surgical risk in infants with associated intracardiac defects. Late follow-up shows the salutary effects of repair of the coarctation on hypertension.

Adolescent↗
PubMed1976

Aneurysm of the membranous ventricular septum. Surgical consideration and experience in 29 cases.

Twnety-nine cases of aneurysm of the membranous septum in association with various cardiac abnormalities are described. These aneurysms are more common than has been previously thought (10% of the total associated anomalies managed surgically). The patients' ages ranged from 3 months to 28 years. All of the 29 patients were divided into three groups. Group I consisted of 15 patients with ventricular septal defect (VSD), 5 of whom had associated artrial septal defect (ASD). Group II consisted of 5 patients with VSD and pulmonic obstruction, and Group III comprised 9 patients with transposition of the great arteries (TGA). Complete correction was performed in all the patients, and the aneurysm was imbricated in the suture line of the VSD in all cases but one. There was only one hospital death, the result of subpulmonic obstruction. This occurred in the first patient of this series, who had aneurysm of the membranous septum in TGA and VSD and in whom the aneurysm was not suspected preoperatively and was overlooked at surgery. There were no late deaths. In 5 patients a small residual VSD and in 3 patients a small recurrent aneurysm were found in a postoperative study. When these accompanying aneurysms are encountered during surgery or are previously diagnosed, resection or imbrication of the sac should be accomplished in order to prevent further enlargement or postoperative arrhythmias and, especially in TGA, to avoid fatal subpulmonic obstruction as occurred in our only death. According to the present data, in the presence of an aneurysm, even a small VSD should be closed by a patch and the aneurysm should perhaps be excised.

Adolescent↗
PubMed1976

Human thymus cells. Excellent responders but poor stimulators in 'One Way' mixed lymphocyte reaction.

Human allogeneic 'one-way' mixed lymphocyte reactions between thymus cells and thymus cells were entirely absent. Of twenty-one mixed lymphocyte reactions between peripheral blood lymphocytes as responding cells and thymus cells as stimulating cells, only eleven had a weak but significant reaction. In contrast, a highly significant response was observed in each of eighteen mixed lymphocyte reactions between thymus cells as responding cells and peripheral blood lymphocytes as stimulating cells and in each of eleven mixed lymphocyte reactions between peripheral blood lymphocytes and peripheral blood lymphocytes. These findings indicate that the thymus cells (T lymphocytes) possess excellent proliferative capacity, with little or no stimulating capacity, while peripheral blood lymphocytes (T and B lymphocytes), on the other hand, are good responders, as well as good stimulators, in the mixed lymphocyte reaction.

Antibodies↗
PubMed1976

Human thymus cells: blastogenic response to mitogens, antigens and allogeneic cells.

Over 90 per cent of the thymus cells from each of twenty-six donors were T lymphocytes, identified by E-rosetting and less than 3 per cent of the cells were B lymphocytes identified by EAC-rosetting. With advancing age, the proportion of T lymphocytes decreased while that of B lymphocytes increased. The degree of (3H)thymidine incorporation of thymus cells was inversely proportional to the age of the thymus-cell donor. The PHA or PWM- induced blastogenic response of thymus cells gradually increased with advancing age when the response was expressed as the stimulation index. However, the actual rate of (3H)thymidine incorporation in all three groups was rather similar when cells were cultured with mitogens. The difference in stimulation index was due to the variation in incorporation rate in cultures without stimulants. The PHA response was approximately four-fold higher than that of PWM response. Thymus cell response to allogeneic lyphocytes, on the other hand, had no correlation with the age of thymus donor. The most surprising result in the present study was that the thymus cells from each of ten donors, aged 1-14 years, were incapable of responding to all four different recall antigens. Peripheral blood lymphocytes from nine to ten randomly selected age-matched children responded very well to one or more antigens.

Adolescent↗
PubMed1976

Congenital aortic stenosis. Experience with 43 patients.

Between September, 1967, and January, 1975, 43 patients underwent intracardiac repair for congenital aortic stenosis at the Buffalo Children's Hospital. The patients ranged in age from 2 days to 24 years, 6 of them being below one year of age. Valvular aortic stenosis was found in 21 cases (4 infants [Group I-A] and 17 older patients [Group I-B]), discrete subaortic membranous diaphragm in 11 (Group II); diffuse subvalvular muscular obstruction in 3 (Group III), supravalvular stenosis in 4 (Group IV), and multiple-level obstruction in 4 (2 infants [Group V-A] and 2 older patients [Group V-B]). Preoperatively, 58 per cent of the patients were symptomatic and 67 per cent had abnormal electrocardiograms. Associated congenital cardiac defects were found in 28 per cent of the cases. The over-all hospital mortality rate was 9 per cent (3 patients in Group I-A and one in Group V-A), with no deaths occurring in patients older than 3 months of age at the time of operation. Two late deaths occurred (Groups I-B and V-B). A complete heart block developed in one patient (Group III). The average intraoperative peak systolic left ventricular-aortic gradient decreased in all groups after repair but progressively increased in the late hemodynamic studies obtained in symptomatic patients. Six patients were reoperated upon for recurrent obstruction. Late results were evaluated on the basis of symptoms, electrocardiographic findings, valve function, and hemodynamic data. They showed excellent or satisfactory results in 59 per cent of the patients in Group I-B, in 45 per cent in Group II, in 66 per cent in Group III, and in 25 per cent in Group I-V. Results were fair or poor in Groups, I-A, V-A, and V-B. In children and adolescents, effective relief of the obstruction and of the symptoms can be obtained with minimal operative risk and minimal morbidity. In symptomatic infants, despite the high operative mortality rate, surgical intervention is indicated because of the poor prognosis.

Adolescent↗
PubMed1975

Thermodynamics of complex formation between bovine liver glutamate dehydrogenase and analogs of ADP.

A calorimetric study of the thermodynamic parameters for the binding of adenosine, AMP, ADP, and ATP to L-glutamate dehydrogenase shows that the variation of deltaG0 of binding is quite small and is correlated qualitatively both with the effectiveness of these ribonucleotides as activators of the L-glutamate dehydrogenase reaction and with size (for the first three). Much larger variations are observed for the deltaH0 of binding largely compensated by changes in deltaS0, with a zig-zag dependence on the number of phosphate groups. For comparison, the binding parameters are also obtained for the deoxyribose analogs of these compounds as well as cyclic adenosine 3':5'-monophosphate and purine riboside. Salt concentration and buffer composition were shown to affect mainly the entropy changes for ADP binding; and the deltaCp values for binding of AMP and ADP to the enzyme are quite small. It is suggested that the general area of the enzyme surface which includes the binding sites for ADP and its analogs contains a number of functional groups, each capable of an energetically small interaction with some group on one or more of the ligands, but so located that even the largest ligand cannot interact with all of them simultaneously. Each ligand minimizes the free energy of the system by selecting the best pattern of such individual interactions permitted by its geometry. Such a pattern of microheterogeneity of ligand-protein interactions may be a major source of the known specificity of binding in biological systems.

Adenosine↗
PubMed1975

Thermodilution cardiac output measurement in infants and small children following intracardiac surgery.

A modified catheter has been used in conjunction with a thermodilution cardiac output computer for postoperative assessment of cardiac function in infants and children. Because of the small amount of fluid required for each determination and the simplicity of the technique, serial measurements can be done safely. Its use has contributed to the early detection of low output states. It has also proven to be a useful tool for estimating the optimal heart rate in each patient and for assessing the effectiveness of therapeutic measures.

Cardiac Catheterization↗
PubMed1975

Corrective treatment of isolated ventricular septal defect in infancy.

Intracardiac correction of VSD in infants should be indicated if the mortality and morbidity of the operation at this age group is lower than cumulative mortality of pulmonary artery banding plus second-staged procedure mortality. Experience with closure of VSD in 23 patients under 1 yr of age with 4% mortality and low morbidity is presented. Indications for operation are: (1) intractable heart failure; (2) persistence or progression of pulmonary hypertension; and (3) failure of banding procedure. Deep hypothermia and circulatory arrest facilitated the intracardiac repair in all patients. Mortality and morbidity related to the banding procedure are emphasized, and it is suggested that banding be restricted only to patients with associated coarctation of the aorta or to patients with multiple muscular ventricular septal defects in whom left ventriculotomy can be safely performed at an older age.

Heart Failure↗
PubMed1975

Anomalous origin of the left coronary artery from the pulmonary artery. Definitive surgical treatment by saphenous vein interposition in a 17-month-old child.

A 17-month-old child underwent successful operative correction of anomalous origin of the left coronary artery from the pulmonary artery by saphenous vein interposition. The clinical, hemodynamic, and angiographic features of the anomaly are presented. Three months after the operation, cardiac catheterization and angiography revealed a patent graft with good antegrade flow and improvement in left ventricular function.

Age Factors↗
PubMed1975

A new instrument for surgical exposure of subaortic and subpulmonic stenosis.

An instrument for providing adequate visualization of the subvalvular area during repair of intracardiac defects is described. Essentially a type of modified nasal speculum, the instrument has proved helpful in performing resections in both subaortic and subpulmonic stenoses by exposing a wider surgical field.

Aortic Stenosis, Subvalvular↗