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Biomedical subjects

A Saxena

Publications and source records attributed to A Saxena.

At least 307 records · Page 17Linked to original sources
PubMed1983

Isolation and reconstitution of the membrane-bound form of dopamine beta-hydroxylase.

Dopamine beta-hydroxylase is present in the bovine adrenal medulla in two forms, soluble and membrane bound. Previous isolation procedures for the membranous hydroxylase have resulted in a form of enzyme identical in subunit structure with the soluble type. We report here the isolation of a membrane-bound form of dopamine beta-hydroxylase which is structurally different from the soluble form. The isolated membranous enzyme has a large apparent molecular weight on gel filtration, is amphiphilic, and contains bound phospholipid which is predominantly phosphatidylserine. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate shows that the membranous hydroxylase contains two nonidentical subunits under both reducing and nonreducing conditions. Under reducing conditions the apparent molecular weights of the two subunits are 70,000 and 75,000 and both contain carbohydrate. The purified membranous hydroxylase binds to phospholipid vesicles and chymotryptic digestion of the bound enzyme suggests that two forms of the membranous hydroxylase exist.

Adrenal Medulla↗
PubMed1983

Antitumor activity of some diorganotin and tin(IV) complexes of Schiff bases.

Some new di-n-butyltin and tin(IV) complexes of the type Bu2SnL, Bu2SnL2 and SnL2 (where L = anions of Schiff bases derived from S-substituted dithiocarbazates and fluoro-aniline) have been prepared and screened for their antitumor activity in P 388 Lymphocyte Leukaemia system. These complexes do not show any toxicity at low dose levels and display T/C values in the range 94-124. Di-n-butyltin complex derived from salicylaldehyde-S-methyl dithiocarbazate has been found to be the most active in this series.

Animals↗
PubMed1980

Pulmonary mucormycosis (Phycomycetes) successfully treated by resection.

Pulmonary mucormycosis (Phycomycetes) is an uncommon fungus infection complicating diabetes mellitus, leukemia, lymphoma, and other debilitating diseases. A review of the literature revealed that of 21 diabetic patients in whom Phycomycetes occurred without underlying malignancy, only 7 survived. These 7 underwent operation. This report concerns another patient with pulmonary mucormycosis who was successfully treated by pulmonary resection.

Diabetes Complications↗
PubMed1979

Epicardial activation of the intact human heart without conduction defect.

To describe the epicardial ventricular activation sequence in the intact human heart, we obtained epicardial maps from 11 patients with normal QRS undergoing open heart surgery. Epicardial breakthrough (EBT), defined as the emergence of a radially propagating epicardial wavefront, occurred in three to five sites in each patient, and was earliest in the anterior right ventricle, 7--25 msec (mean 17 msec) after the onset of the QRS in all patients. Subsequent EBT occurred in the inferior right ventricle (10 sites in 10 patients), in the anterolateral left ventricle (13 sites in 10 patients), and the inferior left ventricle (eight sites in seven patients). Latest epicardial activation (LEA), defined as the latest site of recordable epicardial activity, occurred in the basal segments in all patients, anteriorly in the right ventricle in five patients, and inferiorly in six patients, four on the right and two on the left. LEA occurred 63--96 msec (mean 77 msec) after the onset of the QRS, and was recorded within 20 msec of the end of the QRS in all patients. Sequence of epicardial activation reflected a fusion process among the wavefronts. This descriptive and quantitative data should provide a suitable basis for comparison of abnormal ventricular activation sequences in patients undergoing surgery for preexcitation or ventricular tachycardia.

Adult↗
PubMed1978

Delayed mediastinal infection after ventricular aneurysm resection.

A patient developing delayed mediastinal infection following ventricular aneurysm resection and double coronary bypass is presented. The source of sepsis was infection of a ventriculotomy incision that had been closed with Teflon-felt buttresses. Diagnosis was established by an increasing opacity on the lateral chest roentgenogram with a stable sternal wound. Treatment was ultimately successful only after removal of the infected Teflon and replacement by simple mattress closure. The need to remove the infected foreign body was clearly established by the initially unsuccessful attempt at simple debridement.

Heart Aneurysm↗
PubMedDate not supplied

Is prognostication in congenital diaphragmatic hernia possible without sophisticated investigations?

Congenital diaphragmatic hernia is a complex disorder, in which the anatomical defect is only one part of the spectrum of disease. Hypoplasia of lung complicated by pulmonary hypertension and right to left shunting results in serious hypoxemia. Many factors, based on degree of alterations in respiratory physiology and involving analysis of blood gases and acid base systems, have been used in an attempt to prognosticate the outcome. Majority of these investigations are not available in a modest set up like ours. The case records of all 20 patients admitted and operated for congenital diaphragmatic hernia in pediatric surgery unit of Government Medical College Hospital, Jabalpur from 1978 to 1997 were reviewed retrospectively in an attempt to prognosticate without the sophisticated investigations. It was found that even in a very modestly equipped hospital it is possible to prognosticate--to some extent--the outcome in these cases. Major prognosticators found were APGAR score (if child born in hospital), late age of presentation, location of stomach and identification of hernial sac.

Female↗
PubMedDate not supplied

Clinical course of isolated ventricular septal defect: an Indian experience.

To define the clinical course of ventricular septal defect, 410 consecutive patients with isolated ventricular septal defect were evaluated over a period of 13 years. Their age ranged from 12 days to 24 years at the time of first visit to the hospital. Patients with less than 2 years follow-up period were excluded. One hundred and fifty seven patients were one year of age or less. The left to right shunt size remained the same in 52.4% of cases. In 34.4% the shunt size decreased, with complete closure of ventricular septal defect in 8.8%. Closure of ventricular septal defect was observed even in patients who had initially presented with large left to right flow, and congestive heart failure in infancy. Right ventricular outflow tract obstruction developed in 8.5% of patients usually between 2 and 10 years of age. Murmur of aortic regurgitation appeared in 8.9% on follow-up. Infective endocarditis developed in 6 cases. The unfortunate complication of Eisemenger's complex was seen in 3 patients; they had not returned for follow up for a long period of time. Hence, our data show that the left to right shunt across the ventricular septal defect decreases in about one-third of patients. However, a regular follow up is essential to prevent development of Eisenmenger's complex and for early detection of other complications like aortic regurgitation and right ventricular outflow tract obstruction.

Adolescent↗
PubMedDate not supplied

Prostaglandin E1: first stage palliation in neonates with congenital cardiac defects.

E-type prostaglandins (PGE1) can effectively maintain the patency of the ductus arteriosus in neonates. Its use, therefore can be life saving in infants born with ductus dependent congenital heart disease. Although PGE1 is available for over two decades in western world, it has been introduced in India only since April, 1995. Various cardiac defects where PGE1 is useful include (a) lesions with ductus dependent pulmonary blood flow e.g. pulmonary atresia with or without ventricular septal defect, critical valvular pulmonic stenosis etc, (b) lesions with ductus dependent systemic blood flow e.g. critical aortic stenosis, coarctation of aorta, interruption of aortic arch etc, and (c) admixture lesions like transposition of great arteries. The drug is given as a continuous intravenous infusion. The initial dose is 0.05 to 0.4 ug/kg/min, infusion rate must be decreased to 0.01 ug/kg/min as soon as the desired effect is achieved as incidence of side effects is more at higher doses. Serious side effects include apnoea, hypotension, hyperthermia, seizures etc. We have used this drug in 43 infants ranging in age from one to forty five days. Beneficial response was seen in 41 of 43 infants and the major side effect was apnoea (seen in 5 of 32 spontaneously breathing infants). Unfortunately the high cost of the drug prohibits its wide spread and long term use. PGE1 is a life saving drug for infants born with ductus dependent congenital cardiac malformations. It helps in stabilizing these patients prior to further surgical palliation or correction.

Alprostadil↗