Search PubMed⌕ Search

Biomedical subjects

R C Bansal

Publications and source records attributed to R C Bansal.

At least 37 records · Page 2Linked to original sources
PubMed1994

In vivo effects of isatin on certain enzymes, lipids & serotonergic system of rat brain.

Isatin (10 microM) strongly inhibited the activity of rat brain monoamine oxidase-B (MAO-B) in vitro. At millimolar concentrations (1-10 mM) it inhibited brain acetylcholinesterase (AChE) and sodium, potassium-adenosine triphosphatase (Na+, K(+)-ATPase) activity also. However, isatin did not affect these enzymes after both acute and chronic treatments in vivo. Administration of isatin to rats at 300 mg/kg body weight for 2 and 6 h significantly raised brain serotonin levels. Chronic treatment for 20 days resulted in enhanced brain glycolipids and plasmalogen levels. There was no change in the levels of 5-hydroxy indole acetic acid (5 HIAA), phospholipids, cholesterol and gangliosides under these conditions.

Animals↗
PubMed1994

Inhibition of rabbit intestinal brush border sucrase by indolin 2,3-dione (isatin) at pH 5.0.

Isatin (10 mM) inhibited the activity of rabbit brush border sucrase by 60% at pH 5.0 but it had no effect on enzyme activity around neutral pH. Isatin inhibition of sucrase was unaffected by Na+ ions but K+ and Cs+ ions reduced enzyme inhibition, partially. Kinetic analysis revealed that sucrase inhibition by isatin at acidic pH was non-competitive with Ki of the order 6.5-7.8 mM. Isatin together with 4 mM harmaline or iodoacetate (3 mM) or dithionitrobenzene (2 mM) yielded 80-85% inhibition of the enzyme. These observations suggest that inhibitory sites for isatin, harmaline and -SH group reacting agents are distinct in rabbit brush border sucrase.

Animals↗
PubMed1994

Determinants of the rate of right ventricular pressure rise by Doppler echocardiography: potential value in the assessment of right ventricular function.

Tricuspid regurgitation (TR) is common and the rate of right ventricular (RV) pressure rise in early systole can be obtained from the TR velocity profile. Right ventricular function has important implications in patients with valvular heart disease. Fifty five patients with mild or moderate TR and a wide range of pulmonary artery (PA) pressures were studied. The RV dP/dt was obtained as the ratio of the calculated rise in RV pressure from 0.5 m/s to 1.5 m/s of the TR velocity signal (8 mmHg based on simplified Bernoulli equation) to the time taken for this change. The RV dP/dt correlated positively with PA systolic pressure (r = 0.73, p < 0.001), tricuspid anular plane systolic excursion which is an echocardiographic index of RV ejection systolic function (r = 0.45, p < 0.001) and left ventricular (LV) fractional shortening (r = 0.40, p < 0.01). Multivariate analysis showed that all these three parameters independently influenced RV dP/dt (multivariate R = 0.83) accounting for 69% of its variability. In conclusion, it is suggested that right ventricular dP/dt is easily obtainable from Doppler TR velocity signal. It is influenced independently in a positive manner by PA systolic pressure and RV and LV systolic function. Despite its predominant dependence on PA systolic pressure, it may give useful insight into RV systolic function for a given level of PA pressure. It may also be useful for longitudinal follow up of the RV function in patients with heart disease.

Adult↗
PubMed1992

Transesophageal echocardiographic recognition of subaortic complications in aortic valve endocarditis. Clinical and surgical implications.

BACKGROUND: Secondary involvement of the mitral-aortic intervalvular fibrosa and the anterior mitral leaflet (subaortic structures) can occur in patients with aortic valve endocarditis. The secondary involvement of these structures occurs as a result of direct extension of the infection from the aortic valve or as a result of an infected aortic regurgitant jet striking the ventricular surfaces of the mitral-aortic intervalvular fibrosa and the anterior mitral leaflet. The abscess of mitral-aortic intervalvular fibrosa can expand to form an aneurysm. Subsequently, this mitral-aortic intervalvular fibrosa aneurysm can develop a perforation and communicate with the left atrium, resulting in the systolic regurgitation of blood from the left ventricular outflow tract into the left atrium. Secondary infection can also occur on the ventricular surface of the anterior mitral leaflet and result in the formation of an aneurysm or perforation of anterior mitral leaflet. METHODS AND RESULTS: This study examines the utility of transesophageal echocardiography in the detection of these subaortic complications in 55 consecutive patients with aortic valve endocarditis. A total of 24 patients (44%) had involvement of subaortic structures, including four with an abscess in the mitral-aortic intervalvular fibrosa, four with mitral-aortic intervalvular fibrosa aneurysm, seven with perforation of the mitral-aortic intervalvular fibrosa with communication into the left atrium, two with an aneurysm of the anterior mitral leaflet, and seven with perforation of the anterior mitral leaflet. The transesophageal echocardiographic findings were confirmed at surgery in 20 patients and at necropsy in two. By comparison, transthoracic echocardiography visualized these lesions in five of 24 patients (21%), including none of four with mitral-aortic intervalvular fibrosa abscesses, two of four with mitral-aortic intervalvular fibrosa aneurysms, one of seven with mitral-aortic intervalvular fibrosa perforations, one of two with anterior mitral leaflet aneurysms, and one of seven anterior mitral leaflet perforations. Eccentric mitral regurgitation-type systolic jets were noted in eight additional patients by transthoracic color flow imaging, and this finding suggested the possibility of these unusual subaortic complications. If these patients are included, then transthoracic echocardiography suggested the presence of these subaortic complications in 13 of 24 patients (54%). CONCLUSIONS: The results indicate that 1) involvement of the subaortic structures in patients with aortic valve endocarditis may be more common than previously recognized, 2) patients with aortic valve endocarditis and eccentric jets of mitral regurgitation on transthoracic echocardiography should undergo further evaluation by transesophageal echocardiography to exclude these unusual complications, 3) precise recognition of these complications is of value in the optimal medical and surgical management of these patients, and 4) these complications may be responsible for unexplained congestive heart failure and hemodynamic deterioration in some patients with aortic valve endocarditis.

Abscess↗
PubMed1990

Role of two-dimensional echocardiography, pulsed, continuous wave color flow Doppler techniques in the assessment of ventricular septal rupture after myocardial infarction.

Two-dimensional echocardiography, pulsed and continuous wave Doppler techniques were used for the evaluation of 15 consecutive patients (9 men, 6 women; mean age 71 years, range 61 to 79) with ventricular septal rupture due to acute myocardial infarction (7 anterior, 8 posterior). Standard and modified off-axis 2-dimensional echocardiographic views from parasternal, apical and subcostal windows correctly identified this defect in 14 of the 15 patients. Pulsed Doppler echocardiography confirmed the presence of left-to-right-sided shunt by showing a high-velocity, aliased, systolic flow and a low-velocity diastolic flow in the right ventricle in 14 patients. Continuous wave Doppler echocardiography showed a high-velocity systolic and low-velocity diastolic flow signal of left-to-right shunt in 14 patients. Color flow Doppler imaging identified a left-to-right shunt in all 6 patients in whom it was performed. Doppler and 2-dimensional echocardiographic studies missed a small apical septal defect in 1 patient with anteroseptal myocardial infarction. Two-dimensional echocardiography correctly diagnosed right ventricular infarction in all 5 patients with posteroinferior infarction. Ventricular septal rupture and/or left-to-right-sided shunt was confirmed in all 15 patients by the following: surgical inspection in 11, necropsy in 3, left ventricular cineangiography in 5 and right-sided heart catheterization and oximetry data in 13 patients. Data indicate that 2-dimensional echocardiography correctly shows the precise location of septal rupture in most patients after acute myocardial infarction and allows assessment of left and right ventricular infarction and function.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Platypnea-orthodeoxia as a cause of unexplained hypoxemia in an 82-yr-old female.

We describe an 82-yr-old patient with platypnea-orthodeoxia without identifiable lung disease in whom the diagnosis was suspected because of clinical history, echocardiography, and orthostatic measurement of arterial blood gases. Recumbent and upright cardiac catheterization techniques confirmed the presence of orthostatic variation in the degree of right to left shunt across the fossa ovalis. This was successfully treated by surgical closure of the interatrial communication in the region of the fossa ovalis.

Aged↗
PubMed1990

Left ventricular outflow tract to left atrial communication secondary to rupture of mitral-aortic intervalvular fibrosa in infective endocarditis: diagnosis by transesophageal echocardiography and color flow imaging.

Infection of the mitral-aortic intervalvular fibrosa occurs most commonly in association with infective endocarditis of the aortic valve. Infection of the aortic valve results in a regurgitant jet that presumably strikes this subaortic interannular zone of fibrous tissue and produces a secondary site of infection. Infection of this interannular zone then leads to the formation of subaortic abscess or pseudoaneurysm of the left ventricular outflow tract. This infected zone of mitral-aortic intervalvular fibrosa or subaortic aneurysm can subsequently rupture into the left atrium with systolic ejection of blood from the left ventricular outflow tract to the left atrium. This report describes the echocardiographic findings in three patients with pathologically proved left ventricular outflow tract to left atrial communication. Precise preoperative diagnosis is important, and this lesion should be differentiated from ruptured aneurysm of the sinus of Valsalva and perforation of the anterior mitral leaflet. Transthoracic echocardiography using color flow imaging and conventional Doppler techniques may show an eccentric mitral regurgitation type of signal in the left atrium originating from the region of the left ventricular outflow tract. However, transesophageal echocardiography provides an accurate preoperative diagnosis and should be used intraoperatively during repair of such lesions.

Adult↗
PubMed1990

Comparative evaluation of rate modulated dual chamber and VVIR pacing.

While dual chamber pacing is considered superior to VVI pacing at rest, there is a continuing debate as to the relative benefit of AV synchrony versus rate increase with exercise. To evaluate this question and to correlate different methods of evaluation, 14 patients with DDDR pacemakers were studied using serial treadmill exercise test with a CAEP protocol. Patients were exercised in DDD, DDDR, and VVIR modes. Echo-Doppler cardiac outputs were determined and pulmonary gas exchange was measured during exercise. There was a significant improvement in cardiac output with exercise in the DDDR versus VVIR modes, and in DDDR versus DDD modes in patients with chronotropic incompetence. There were small increases in exercise duration in DDDR versus VVIR modes, and small but consistent increases in VO2 at all levels of exercise, though not statistically significant. In this group of patients, DDDR pacing was superior to VVIR pacing, and superior to DDD pacing when chronotropic incompetence was present.

Aged↗
PubMed1990

Impact of transesophageal color flow Doppler echocardiography in current cardiology practice.

Of 3,480 patients who were referred for cardiac ultrasound evaluation, 230 patients (6.6%) underwent transesophageal echocardiography because the transthoracic study was not feasible, technically inadequate, or provided insufficient diagnostic information for optimal patient management. There were 149 inpatients and 81 outpatients. The majority (182 patients, 79%) had aortic or mitral disorders. In 166 patients (72%), transesophageal echocardiography played a significant role in patient management. Transesophageal echocardiography was most useful in evaluating diseases of the aorta (dissection, root abscess, or aneurysm), mitral prosthesis, complications of endocarditis, left atrial appendage thrombi, and in determining the cause of mitral insufficiency. Transesophageal echocardiography was useful in the evaluation of critically ill patients and those with severe lung disease.

Adolescent↗
PubMed1990

Visualization of mitral valve aneurysm by transesophageal echocardiography.

This article describes the transesophageal echocardiographic findings in a patient with pathologically proven mitral valve aneurysm. This aneurysm probably occurred as a complication of aortic valve endocarditis. Transesophageal echocardiography showed a saccular structure attached to the left atrial side of the anterior mitral leaflet with systolic expansion and diastolic collapse, and its orifice was visualized with excellent resolution. Transesophageal echocardiography is a useful diagnostic tool for evaluation of mitral valve aneurysm.

Aortic Valve↗
PubMed1990

Doppler-derived rate of left ventricular pressure rise. Its correlation with the postoperative left ventricular function in mitral regurgitation.

A new Doppler-derived index of the rate of left ventricular (LV) pressure rise (delta P/delta t) was evaluated for the prognostic stratification of patients with chronic mitral regurgitation. The index is derived from the continuous wave Doppler mitral regurgitation signal by dividing magnitude of LV-left atrial pressure gradient rise (delta p) between 1 and 3 m/sec of the mitral regurgitation velocity signal by the time taken (delta t) for this change. We studied the LV delta P/delta t and other echocardiographic indexes of LV function before and after mitral valve surgery in 25 patients with chronic, severe mitral regurgitation in the absence of significant coronary artery disease. There was a good correlation between postoperative ejection fraction (EF) and the derived LV delta P/delta t (r = 0.75, p less than 0.001). The other echocardiographic parameters that correlated with postoperative EF were LV end-systolic dimension (r = -0.7, p less than 0.001), end-systolic volume (r = -0.69, p less than 0.001), end-diastolic dimension (r = -0.58, p less than 0.01), end-diastolic volume (r = -0.57, p less than 0.01), preoperative EF (r = 0.69, p less than 0.001), end-systolic wall stress (r = -0.61, p less than 0.01), and end-systolic wall stress normalized for end-systolic volume index (r = -0.45, p less than 0.05). With multiple regression, the LV delta P/delta t and LV end-systolic dimension (ESD) were shown to be independent predictors of postoperative EF. The postoperative EF could defined by the equation: 43 + 0.8 square root delta P/delta t--0.53 ESD (mm) (r = 0.86).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗