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Biomedical subjects

S Subramanian

Publications and source records attributed to S Subramanian.

At least 289 records · Page 16Linked to original sources
PubMed1978

Chemotherapy of sarcoma. A comparison of three regimens.

Three regimens have been used in the chemotherapeutic management of 75 adults with sarcoma. Methotrexate alone was used in 41 cases, a five-drug regimen was given in 12 cases, and adriamycin, T.I.C.-mustard, and methotrexate were given to 22 patients. Remissions, sometimes prolonged, were achieved with each regimen, and none was obviously better than the others. Because of the higher response-rate of primary or locally recurrent tumours it is suggested that sensitivity to drugs should be assessed earlier in the disease. It is proposed that a randomised study of methotrexate versus combination chemotherapy should be started in particular sarcoma subgroups, such as leiomyosarcoma and fibrosarcoma.

Adult↗
PubMed1978

Bilateral atrial myxomas. Echocardiographic considerations.

In this report we describe a patient with bilateral atrial myxomas, which were diagnosed preoperatively by echocardiography and angiography, and successfully removed. The excised tumor mass consisted of mobile right and left atrial myxomas connected by a common stalk which passed through the atrial septum, collectively resembling the shape of a dumbbell. Preoperative echocardiographic and angiographic observations were instrumental in planning the surgical approach, and correlated well with intraoperative findings and with the anatomic configuration of the intact pathologic specimen. Diagnostic aspects of echocardiography are emphasized as they relate to both isolated and bilaterally-occurring atrial myxomas.

Adult↗
PubMed1978

Thermodynamics of the glutamate dehydrogenase catalytic reaction.

The enthalpy change for the oxidative deamination of glutamate by NADP+ catalyzed by bovine liver glutamate dehydrogenase has been determined calorimetrically. The deltaH0 values are 64.6 +/- 1.2 kJ/mol and 70.3 +/- 1.2 kJ/mol at 25 and 35 degrees C respectively. The equilibrium constants for the reaction at the two temperatures were determined spectrophotometrically. This enabled the determination of deltaG0 and deltaS0 of the reaction as well. deltaH0 values were also determined for the reaction using an alternative coenzyme and the deuterated substrate.

Calorimetry↗
PubMed1978

Sinus venosus atrial septal defect associated with partial anomalous pulmonary venous drainage: surgical repair.

This report descrbies a new technique for the repair of sinus venosus atrial septal defect associated with partial anomalous pulmonary venous drainage. A right atrial wall flap is used both to deflect the anaomalous venous blood into the left atrium and to close the atrial septal defect. Then an atrioplasty is performed. This method does not employ any foreign materials, avoids injury to the sinoatrial node and internodal tracts, and minimizes the risk of obstruction of the ostia of the anomalous pulmonary veins and superior vena cava.

Adolescent↗
PubMed1978

Interaction of methotrexate, folates, and pyridine nucleotides with dihydrofolate reductase: calorimetric and spectroscopic binding studies.

The thermodynamic parameters, deltaG, deltaH, and deltaS characterizing the tight binding of methotrexate, folates, and pyridine nucleotides to chicken liver dihydrofolate reductase (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) have been determined from calorimetric and fluorescence measurements. At 25 degrees the binding of NADPH and NADP+ is characterized by small negative enthalpies and large positive entropies whereas the binding of the folates and methotrexate is accompanied by large negative enthalpies and small negative entropies. In addition, the enthalpy of methotrexate-enzyme interaction demonstrates a proton transfer associated with binding; this is not the case with folate and dihydrofolate, thus confirming the conclusions drawn from the observed difference spectra characteristic of the interaction of methotrexate and substrates with the enzyme. The implications of these results are discussed in terms of the nature of the binding process, conformational changes in the enzyme, and the nature of the active site region.

Animals↗
PubMed1978

Review: surgery for transposition of the great arteries in the first year of life.

Elective intracardiac repair by the Mustard operation is recommented in patients with transposition of the great arteries and intact ventricular septum in the first year of life (Fig. 1). In patients with associated ventricular septal defect in the first three months of life, early banding followed by early debanding before the first year of life is recommended. When the left ventricular outflow tract obstruction is discrete at valvular or subvalvular level, Mustard operation, closure of the ventricular septal defect and direct relief of out-flow obstruction is acceptable, but in patients with an unfavorable left ventricular outflow tract anatomy, a preliminary shunt followed by a Rastelli operation after the age of four years will probably result in a greater salvage. The utilization of surface induced profound hypothermia and circulatory arrest allows for more precise and rapid surgery and is shown to be a definite advantage in the very young infant.

Child, Preschool↗
PubMed1978

Further studies on pulmonary oedema of high altitude. Abnormal responses to hypoxia of men who had developed pulmonary oedema at high altitude.

101 Indian soldiers, 57 of whom had developed pulmonary oedema of high altitude (POHA) and 44 who had not developed this condition in spite of being at high altitudes for over 2 years, were investigated for observing the differences, if any, in their reaction to acute hypoxic stress. Each subject was made to breathe a 10% hypoxic mixture for 5 min. Haemodynamic parameters like pulmonary artery pressure (systolic, diastolic and mean), brachial artery pressure, wedge pressure, cardiac output, minute ventilation, arterial oxygen saturation and oxygen uptake before and at the end of hypoxic breathing were estimated. In addition, results of the cold pressor test were recorded and the Vd/Vt ratio was estimated. The results obtained in the present study confirmed those obtained in our previous studies. In addition, it was observed that oxygen uptake was significantly higher and oxygen saturation lower after hypoxia in the POHA subjects than in the controls. Certain parameters for screening of subjects possibly susceptible to POHA have been suggested.

Adult↗
PubMed1978

Deep hypothermia in infant cardiac surgery.

The value of infant cardiac surgery using deep hypothermia remains a debate. A steady number of cardiac centers have consented to this approach in spite of some filibuster. Physiologists are frightened, anesthetists may find it cumbersome, but surgeons using it enjoy the ease of correction in a bloodless and relaxed heart. The cardiologists may document acceptable results, but we also need the alert feedback from the provider of long-term health care--the pediatrician--to document possible flaws of this pristine modality. This article is intended to familiarize the pediatrician with the method of deep hypothermia: its origin, application, and appeal for consumer protection.

Cardiac Surgical Procedures↗
PubMed1978

RECONSTRUCTION OF THE RIGHT VENTRICULAR OUTFLOW TRACT WITH A POSTERIOR MONOCUSP VALVE.

Reconstruction of the right ventricular outflow tract with sections of pericardium or with Dacron patches often leads to pulmonary regurgitation. This report presents a technique for minimizing regurgitation by creating a single posterior leaflet using the patient's own valve. After incision of the pulmonary artery and valvular ring, the valve is brought forward to cover the opening of the reconstructed pulmonary artery. This time-saving technique avoids the risk of calcification which usually accompanies the use of homografts and heterografts.

Journal Article↗
PubMed1978

Free radicals produced in human lenses by a biphotonic process.

Cataractous and noncataractous human lenses were irradiated with ultraviolet (UV) light, and the resulting triplet and radical species were studied by electron paramagnetic resonance spectroscopy. Evidence is presented that free radicals are produced by a biphotonic process involving tryptophan as an intermediate triplet. This makes free radical production energetically feasible. A possible link between incident UV light and cataract formation is suggested.

Aged↗
PubMed1978

Mycetomas caused by Streptomyces pelletieri in Madras, India.

Biopsy specimens from 93 patients with mycetoma were examined histologically; Streptomyces pelletieri was found in 12 cases. In addition, two cases of actinomycetoma pedis in which S pelletieri has been isolated in culture are described. In both, the characteristic red granules were seen.

Adult↗
PubMed1978

Tetralogy of Fallot. Occlusion of the ventricular septal defect due to accessory tricuspid valve leaflet and an associated membranous aneurysm.

A unique case of tetralogy of Fallot is presented in a 3 7/12-yr-old white female. At surgical repair, a ventricular septal defect smaller than usual was demonstrated in the usual infracristal position. The ventricular septal defect was partially obstructed from the right side of the ventricular septum by adherence of an accessory tricuspid leaflet. An associated membranous aneurysm, presumably acquired, was occluding the ventricular septal defect at its outlet almost completely. The literature has been reviewed and the pathophysiology of this lesion is discussed, underlining the nature and plausible development of the membranous aneurysm.

Child, Preschool↗
PubMed1978

Current status of open heart surgery in infancy.

The enthusiasm for primary intracardiac surgery in symptomatic infants with congenital cardiac disease generated by early successful reports continues. The results obtained to data indicate that when surgery is carried out in extremely ill symptomatic infants, the mortality is high but still superior to staged procedures. When surgery is performed relatively electively, to prevent complications related to the unnatural history of the disease, the results of surgery are excellent. Profound hypothermia and circulatory arrest have contributed greatly towards facilitating technical surgery and postoperative management. An increasing number of centers are utilizing conventional cardiopulmonary bypass with hypothermia to achieve the same result. One of the major objections to using hypothermia and cardiocirculatory arrest has been the fear of cerebral complications, both neurological and psychomotor. Our follow-up studies on an unselected group of patients have shown very clearly that when the technique was applied carefully with strict attention to detail, late neurological and psychomotor complications were virtually nil. The IQs of these children fall within the normal distribution curve of a comparable group of noncardiac children. In view of these late follow-up findings, we feel that hypothermia and cardiocirculatory arrest are safe modalities in handling infants undergoing open intracardiac surgery. There is probably still a place for two-stage procedures in selected lesions and these are complex transposition of the great arteries and perhaps as a clinical trial in a randomized group of infants with tetralogy of Fallot. With the exception of these lesions, early correction of all operable symptomatic heart defects in infants is recommended.

Cardiopulmonary Bypass↗