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Biomedical subjects

S Sen

Publications and source records attributed to S Sen.

At least 433 records · Page 24Linked to original sources
PubMed1984

Sustained atrial flutter after cardiac surgery: successful termination by rapid atrial pacing.

For termination of sustained atrial flutter, 28 rapid atrial stimulations were performed in 26 patients undergoing cardiac surgery, including coronary bypass surgery, and valvular heart surgery as well as surgery for primum and secundum atrial septal defect and anomalous connection of the pulmonary veins. In 18 patients rapid atrial pacing was successful in directly converting a flutter to a sinus rhythm, in 5 patients after a short period of transient atrial fibrillation. Atrial flutter could be changed to atrial fibrillation in a further 3 patients who remained in permanent atrial fibrillation and subsequently underwent DC cardioversion. Our results demonstrate that rapid atrial pacing is very effective in the treatment of sustained atrial flutter in patients following cardiac surgery and may be used alternatively to DC countershock.

Adolescent↗
PubMed1984

Steroidogenic properties of a new aldosterone-stimulating factor: interaction with angiotensin II and adrenocorticotropin during variations of dietary sodium.

We investigated the in vitro steroidogenic activity of a new aldosterone-stimulating factor (ASF). Aldosterone responses of adrenal zona glomerulosa cells to ASF were assessed in response to variations in sodium intake and during incubation with either ACTH or angiotensin II (AII). Studies were performed in collagenase-dispersed adrenal capsular cells harvested from male New Zealand White rabbits that were on either regular or low sodium diets for 7-10 days. ASF, AII, and ACTH produced dose-dependent increases in aldosterone production. In cells from sodium-replete rabbits, the concentrations required to elicit the half-maximum response (ED50) were 2.2 +/- 0.3 (+/-SE) X 10(-11), 7.2 +/- 1.1 X 10(-10), and 3.4 +/- 0.5 X 10(-8) M for ACTH, AII, and ASF, respectively. Sodium depletion increased maximal responses but not sensitivity to AII and ACTH; responses to ASF were essentially unchanged. Large concentrations of ASF (10(-7) M) potentiated AII-induced aldosterone responses of adrenal capsular cells from sodium-depleted, but not sodium-replete, rabbits. In marked contrast, similar concentrations of ASF inhibited ACTH-induced aldosterone production of adrenal capsular cells from both sodium-replete and sodium-depleted rabbits. It is concluded that ASF has its own intrinsic steroidogenic activity. Furthermore, although large concentrations of ASF potentiate AII responses in sodium-depleted animals, ASF inhibits the aldosterone-stimulating activity of ACTH in both sodium-replete and sodium-depleted animals.

Adrenocorticotropic Hormone↗
PubMed1984

Sudden cardiac death during ambulatory Holter monitoring. Report on 3 documented cases.

Three cases are presented who died suddenly while being continuously monitored on ambulatory Holter ECG. Two patients with coronary artery disease and severe left ventricular dysfunction after multiple myocardial infarctions died instantly from ventricular fibrillation; this was preceded by a rapid uniform ventricular tachycardia in one patient with normal Q-T interval and by polymorphous ventricular tachycardia in the other whose Q-T was prolonged on combined antiarrhythmic therapy with propafenone and mexiletine. The third patient died from rapidly progressive circulatory failure and acute pulmonary edema due to secondary cardiomyopathy. Despite its occurrence within 30 min after the onset of symptoms, death was not primarily arrhythmic in origin.

Ambulatory Care↗
PubMed1984

Expression of endogenous murine leukemia virus in transplantable tumor cells and DNA methylation of the viral sequences.

A cell line derived from early passage of a transplantable tumor in athymic mice that initially had been injected with human breast adenocarcinoma cells produced a substantial amount of RNA sequences related to the Kirsten murine leukemia virus. The cell line derived from later passage of transplantation of these tumors diminished viral RNA production. Expression of the viral RNA sequences in these cell lines is inversely correlated with the level of viral DNA methylation in the mouse genome.

Adenocarcinoma↗
PubMed1984

Value of excretory cystography in the diagnosis of bladder tumours.

The value of excretory cystography in diagnosing bladder tumours was assessed in a randomised study. The 10-min, 20-min, and post-voiding films of intravenous urograms of 75 patients with biopsy-proved bladder tumours and of 25 patients with proved normal bladders were randomly reviewed. Overall, 60 of 75 bladder tumours (80%) were correctly diagnosed by review of the roentgenograms. Specificity and sensitivity were comparable (94 and 96% respectively) for patients with papillary tumours greater than or equal to 0.5 cm in diameter, but specificity was low (23%) for those with tumours smaller than 0.5 cm. It is concluded that excretory cystography makes a considerable contribution to the establishment of the diagnosis of papillary bladder tumours greater than or equal to 0.5 cm in diameter.

Carcinoma in Situ↗
PubMed1983

Regression of cardiac hypertrophy. Experimental animal model.

Regression of cardiac hypertrophy has been proven to occur in experimental animals following some types of antihypertensive therapy. However, no direct and necessary correlation can be found between hypertension and cardiac hypertrophy. The effect of different antihypertensive drugs on regression of cardiac hypertrophy varies despite the same degree of reduction in arterial pressure in hypertensive control subjects. Therapy with alpha-methyldopa resulted in reversal of hypertrophy with effective blood pressure control, whereas treatment with vasodilators, namely hydralazine and minoxidil, either did not alter (hydralazine) degree of myocardial hypertrophy or increase it (minoxidil) despite normalization of blood pressure. The biochemical profile of the myocardium after regression of hypertrophy following antihypertensive therapy is not homogeneous; for example, reversal with alpha-methyldopa is associated with increased collagen content, whereas reversal with Captopril did not alter collagen content of the heart. Adrenergic factors seem to play an important role in the modulation of myocardial structure to variations in arterial pressure. Furthermore, in each type of hypertrophy in hypertension, a combination of different factors might be responsible, and it may not be correct to assume that the same factors must be involved in the regression of all types of myocardial hypertrophy.

Age Factors↗
PubMed1983

Antibodies of predetermined specificity detect two retroviral oncogene products and inhibit their kinase activities.

Oligopeptides predicted from the nucleotide sequence of the oncogene v-fes of feline sarcoma virus (FeSV) were synthesized chemically and used to generate specific antibodies. Antisera against a 12-amino-acid-long oligopeptide (12-mer) located 42 residues from the carboxyl terminus of the v-fes coding sequence efficiently recognized the transforming proteins encoded by Snyder-Theilen (ST) and Gardner-Arnstein (GA) strains of FeSV. This 12-mer also contains 10 amino acid residues homologous in order and position to those predicted from the nucleotide sequence of the oncogene v-fps of avian Fujinami sarcoma virus (FSV). The anti-12-mer immunoprecipitated the FSV-specific transforming protein molecules from FSV-transformed cells. Binding of these antipeptide antibody molecules to the v-fes and the v-fps gene products inhibited their associated tyrosine-specific protein kinase (EC 2.7.1.37) activities. The ability to generate such site-specific antisera to the products of related oncogenes will be valuable in the molecular characterization of retroviral transforming proteins and their normal cellular homologs.

Antibody Specificity↗
PubMed1983

Primary peritonitis in children.

Thirty-one children with primary peritonitis were studied. Most of them had been healthy prior to the onset of peritonitis and only one had nephrotic syndrome. There were 27 girls and four boys. The predominant organism in girls was pneumococcus, and in boys staphylococcus. The causative organisms, identified in 27 children, were all Gram positive. Most of the children were between four and 10 years of age. The onset of their illness was sudden with fever, vomiting and abdominal pain. Since in recent years, primary pneumococcal peritonitis has been the commonest type of peritonitis in young girls, our earlier policy of routine laparotomy for peritonitis was given up and in girls aged between four and ten, an attempt at initial pre-operative diagnosis was made by Gram's staining of peritoneal aspirate or vaginal swab. If Gram positive peritonitis was diagnosed, early cases were treated with antibiotics alone and late cases with antibiotics and minilaparotomy for drainage of pus. There was one death. Morbidity and mortality were higher when the period without treatment exceeded one week. The contribution of pre-operative diagnosis by Gram's staining to the provision of optimum treatment is emphasized.

Child↗
PubMed1983

Regression of myocardial hypertrophy and influence of adrenergic system.

Studies of regression of myocardial hypertrophy in spontaneously hypertensive rats (SHR) suggest that the adrenergic system may play an important role in the reversal of hypertrophy. The effect of propranolol on reversal of hypertrophy, however, is still controversial. This study describes the effect of propranolol, given alone or in combination with hydralazine in different ratios for 4 wk, on blood pressure (BP), ventricular weight, and myocardial catecholamine (MC) concentrations. The data show that a certain ratio of propranolol to hydralazine (750:30) leads to moderate BP control (196-156 mmHg) without increased MC (634 vs. 552 ng/g) and moderately reduced hypertrophy. Reduction of BP alone with increased MC (hydralazine alone) or reduction of MC without BP control (propranolol alone) failed to reduce hypertrophy. A significant correlation between both ventricular weight and heart rate with MC (r = 0.6) was obtained by multiple regression analysis. This study suggests that adrenergic factors seem to play an important role in modulating structural cardiac response to variations in arterial pressure.

Animals↗
PubMed1983

Megamodulin, a cation binding protein from Escherichia coli and its effect on bacterial RNA polymerase.

The versatile multication binding protein, otherwise known as the stimulatory protein kinase modulator (PKMs) or megamodulin has been isolated from Escherichia coli and it has been found to stimulate E. coli RNA polymerase holoenzyme. It has been hypothesized that megamodulin may regulate RNA polymerase activity by blocking the pausing mechanism and/or increased chain elongation activity during the process of transcription, and also may play an important role in protein synthesis.

Bacterial Proteins↗
PubMed1983

Comparative estimation of octopamine in the aortic smooth muscle, plasma and red blood cells of spontaneously hypertensive and Wistar Koyoto control rats.

Octopamine is an alpha agonist, the levels of which vary with age and in pathophysiological conditions. The levels of octopamine were found to be higher in the aortic smooth muscle and red blood corpuscles, but lower in the plasma of spontaneously hypertensive rats (SHR) than in the Wistar Koyoto rats. The importance of these variations are discussed.

2-Hydroxyphenethylamine↗