Biomedical subjects

A Bhaskaran

Publications and source records attributed to A Bhaskaran.

6 recordsLinked to original sources

PubMed1999

Fish p53 as a possible biomarker for genotoxins in the aquatic environment.

The p53 gene is a tumour suppressor gene which has a fundamental role in cell cycle control and division, and in mammals certain genotoxic agents induce specific mutations in p53, leading to tumourigenesis. Fish have been investigated as models for studying carcinogens, but as yet very little data exists that links exposure to specific chemicals with the aetiology of tumours found in wild populations. In this study, p53 was sequenced from five species of fish with a view to the possible use of mutations in the highly conserved domains of p53 to identify genotoxins in the aquatic environment. A 0.8 kb fragment of the cDNA encompassing the conserved DNA-binding domain of p53 was sequenced in three Oncorhynchus salmonid fish: coho (O. kisutch), chum (O. keta), and chinook (O. tshawytscha) and full-length p53 cDNAs were sequenced in the puffer fish (Tetraodon miurus) and the barbel (Barbus barbus). The full-length puffer fish and barbel p53 cDNAs were 1834 bp and 1790 bp in length, encoding a 367 aa protein and a 369 aa protein, respectively. The deduced aa sequences of the p53 cDNA in the Oncorhynchus salmon shared a 100% identity in the five conserved regions (I-V). Comparisons of the deduced aa sequences for puffer fish and barbel p53 with other fish p53s revealed a high homology within the conserved DNA binding domain (68-86% for puffer fish and between 66-88% for barbel). "Conserved" domain I was not highly conserved in fish, as it is in mammals, and, therefore, conserved domains II-V are most likely to provide the valuable sequences in fish p53 for use in mutational studies to fingerprint genotoxins in the aquatic environment.

Amino Acid Sequence↗

PubMed1995

Coronary angioplasty for the control of intractable ventricular arrhythmia.

Ventricular arrhythmias (VAs) that occur following an acute extensive anterior myocardial infarction (MI) usually respond to conventional antiarrhythmic regimes of treatment. Rarely, the VA may prove intractable to therapy. This report is of three patients who presented at varying time frames (3 h to 10 weeks) following an anterior MI. They exhibited sustained monomorphic ventricular tachycardia and hemodynamic instability despite multiple antiarrhythmic drug therapy, intravenous magnesium, direct-current cardioversion (DCCV), overdrive pacing (in one case), and intra-aortic balloon counterpulsation (IABP). Although there was no clinical evidence of continuing ischemia and although coronary angiography that was done in each case showed the infarct-related artery (IRA) to subtend akinetic areas on left ventricular (LV) angiogram, percutaneous transluminal coronary angioplasty (PTCA) of the IRA was done in all three cases. Reestablishing patency of the IRA helped in controlling the VA dramatically with average therapeutic doses of antiarrhythmic drugs. All three patients showed this control to have been maintained over a follow-up period of more than 1 year, with partial improvement in LV function and signal-averaged electrocardiogram negative for late potentials. Thus, in patients with extensive infarction and intractable VA, PTCA of the IRA may provide control of VA even in the absence of clinical signs of active ischemia or viable muscle mass.

Angioplasty, Balloon, Coronary↗

PubMed1995

Multivessel coronary angioplasty with anomalous origin of the left main coronary artery.

We report a case of coronary angioplasty to the right coronary artery, the circumflex, and the left anterior descending artery in a patient with anomalous left main coronary artery arising from the right aortic sinus of Valsalva. At angiographically documented follow-up of more than 2 years, the patient remains well without restenosis. This case represents the only such report in the literature. Angioplasty hardware was an important factor in successful crossing and dilatation of multiple severe and distal stenoses in the anomalous left system; appropriate technical details are discussed.

Angioplasty, Balloon, Coronary↗

PubMed1993

A sampling and storage system for arbitrary biomedical waveforms.

This paper describes a microcontroller based system which can sample, monitor and store, and generate biomedical waveforms. The frequency of the output waveform is controllable. The inherent advantage of this system is the programming flexibility offered by the microcontroller. Applications include patient monitoring, test signal generator for repair and maintenance of EEG or ECG monitoring equipment, and a laboratory simulation device for student educational use.

Computer Simulation↗

PubMed1992

Electronic ECG simulator.

This paper describes the design of an ECG simulator which outputs both normal and abnormal waveforms. Both heart rate and signal amplitude may be controlled. Applications include a test signal source for repair/maintenance of ECG monitoring equipment, and as a laboratory simulation device for student educational use.

Computer Simulation↗

PubMedDate not supplied

Multiplane transesophageal echocardiography: our initial experience.

We present our experience in the diagnostic assessment of a wide spectrum of cardiovascular disorders using multiplane transesophageal echocardiography (MP-TEE). Two hundred and seventeen patients in the age range of 11-71 years were subjected to MP-TEE from January to November 1993. The male:female ratio was 1.1:1. One hundred and ten patients had predominantly mitral valve disease of rheumatic origin, eleven had mitral valve prolapse, twenty patients had aortic valve disease and thirty seven patients had more than one valve involvement. Six patients with suspected prosthetic heart valve dysfunction and ten patients of hypertrophic cardiomyopathy were also studied. Two patients had unexplained pulmonary hypertension, three had pericardial disease and three had proximal aortic dissections. Twenty six patients with congenital heart disease were studied of which nineteen had atrial septal defects, one had corrected transposition of great vessels with pulmonic stenosis and one adult had Ebstein's anomaly of the tricuspid valve. In our experience, MP-TEE enhances the versatility of TEE by providing incremental diagnostic information and enhancing delineation of pathology. The procedure was well-tolerated and no complications occurred.

Adolescent↗