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Biomedical subjects

A K Deshpande

Publications and source records attributed to A K Deshpande.

14 recordsLinked to original sources
PubMed1990

Physiological correlates of impedance plethysmographic waveform.

A review of investigations into the origin of impedance plethysmographic waveform is presented in this article. Attempts made by several investigators in the comparison of impedance plethysmographic estimations of peripheral blood flow with that obtained by standard methods are briefly described. Investigations indicating the negligible contribution from contact impedance at body electrode interface are highlighted. Temporal correlation of impedance plethysmographic waveform recorded from thorax with various important events of the cardiac cycle is summarised and various hypotheses on the genesis of this waveform are presented.

Cardiography, Impedance↗
PubMed1990

Diagnosis of aortic occlusive diseases using impedance plethysmography.

Impedance plethysmographic observations have been correlated with aortographic observations in 57 patients suspected of aortic occlusive diseases. Aortic occlusions have been characterised by marked decrease in blood flow index and significant increase in differential pulse arrival time at thigh level bilaterally. Atherosclerotic affection of the aorta has been featured by a bilateral decrease in the value of blood flow index as well as differential pulse arrival time at thigh level. Leriche's syndrome, however, has been found to decrease the blood flow index moderately at thigh in both the legs without any significant change in differential pulse arrival time. Aortography in all the patients has confirmed the diagnosis made by impedance plethysmography.

Aorta, Abdominal↗
PubMed1990

Diagnosis of peripheral arterial occlusive diseases using impedance plethysmography.

Impedance plethysmographic observations have been compared with arteriographic findings in 216 patients with peripheral arterial occlusive diseases. Impedance plethysmographic diagnosis in these patients was obtained by Parulkar's method without apriori knowledge of arteriographic diagnosis. But for minor discrepancy in the anatomical location of the block in few patients, impedance plethysmographic observations correlated very well with arteriographic findings. Impedance plethysmographic diagnosis was found to be correct in 312, wrong in 53, false negative in 8 limbs respectively, yielding a sensitivity of 97.5% and specificity of 98.1% of this technique.

Adolescent↗
PubMed1990

Impedance plethysmographic observations in thoracic outlet syndrome.

Forty patients with symptoms of neuro-vascular compression in the upper extremities were subjected to impedance plethysmographic study using Parulkar's method. Two patients recorded decreased blood flow (BFI) in supine position and were diagnosed as having partial occlusion at subclavian level. Sixteen of the patients recorded decreased BFI on 90 degrees abduction and hyper-abduction. Twelve of these patients had radiological evidence of anomalous cervicle ribs. In remaining four patients extrinsic impression on the subclavian artery due to fibrous deposits was confirmed by arteriography. Remaining 22 patients recorded normal impedance plethysmograms. Impedance plethysmography thus provided a non-invasive modality for confirmation of vascular compression in thoracic outlet syndrome.

Adolescent↗
PubMed1990

Impedance plethysmography of thoracic region: impedance cardiography.

Impedance plethysmograms were recorded from thoracic region in 254 normal subjects, 183 patients with coronary artery disease, 391 patients with valvular heart disease and 107 patients with congenital septal disorder. The data in 18 normal subjects and 55 patients showed that basal impedance decreases markedly during exercise in patients with ischaemic heart disease. Estimation of cardiac index by this technique in a group of 99 normal subjects has been observed to be more consistent than that of the stroke volume. Estimation of systolic time index from impedance plethysmograms in 34 normal subjects has been shown to be as reliable as that from electrocardiogram, phonocardiogram and carotid pulse tracing. Changes in the shape of plethysmographic waveform produced by valvular and congenital heart diseases are briefly described and the role of this technique in screening cardiac patients has been highlighted.

Cardiography, Impedance↗
PubMed1990

Effect of pulmonary circulation on vector impedance cardiogram.

Vector impedance cardiograms in horizontal lead configuration [VICG(H)] were recorded in 34 normal subjects, 18 patients with mitral stenosis, 9 patients with mitral regurgitation, 14 patients with aortic regurgitation and 13 patients with non- cyanotic septal disorders. Data in normal subjects revealed that most of the phase reversal points in VICG(H) waveform did not coincide with those of conventional impedance cardiogram. The shape of VICG(H) waveform and values of VICG indices were observed to be markedly affected in patients having significant alteration in the pulmonary circulation and the changes observed were specific of the type of the disorder. The results of the study suggested that right side of the heart had dominant contribution in generation of VICG(H) waveform.

Adolescent↗
PubMed1978

Acetylcholinesterase differentiation during myogenesis in early chick embryonic cells caused by an inducer RNA.

In the stage 4 chick blastoderm, an area located 0.6 mm posterior to Hensen's node, the post-nodal piece (PNP), consists of an undifferentiated population of cells, since the explants when cultivated in vitro in a variety of media do not develop into any histologically identifiable structures. However, addition of a specific low molecular weight RNA isolated from the 16-day-old chick embryonic heart promotes the appearance of a distinct mode of morphological and biochemical changes that is similar to that of embryonic cardiogenic process. The RNA-induced changes in the PNP also include a marked increase in acetylcholinesterase activity. The increase in enzymatic activity can be measured biochemically, as well as visualized histochemically.

Acetylcholinesterase↗
PubMed1977

A novel RNA affecting embryonic gene functions in early chick glastoderm.

A low molecular weight RNA species (CEH-RNA Fraction 1a) of about 7 S size was isolated from the 16-day-old chick embryonic heart. The RNA was capable of inducing a specific mode of changes in the early embryonic cells of Stage 4 (definitive primative streak stage) chick blastoderm cultivated in vitro. These changes were similar to those of embryonic heart differentiation. RNAs from other sources isolated under identical conditions and synthetic polynucleotides were not effective. In the absence of inducer CEH-RNA, the embryonic cells remained undifferentiated. The dependence of heart-like differentiation on a specific RNA species thus offers an opportunity to test the gene-regulating role of the RNA in an experimentally analyzable biological system.

Animals↗