Biomedical subjects
S Sharma
Publications and source records attributed to S Sharma.
Non-coronary cardiac interventions. The second report of the Non-Coronary Cardiac Intervention Registry, the Cardiological Society of India.
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Coronary artery disease in South Asians. Second meeting of the International Working Group. 16 March 1997, Anaheim, California.
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Epithelial hepatoblastoma in a middle aged woman.
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Acute effect of balloon mitral valvotomy on serial electrocardiographic changes and their haemodynamic correlation.
The effect of acute haemodynamic changes that occur following balloon mitral valvotomy on the electrocardiogram were studied in 25 patients with isolated rheumatic mitral stenosis. Statistically significant changes were observed in the characteristics of P-wave and QRS axis. Patients who showed changes in P-wave had significantly greater fall in left atrial mean pressure (p < 0.025), lesser residual transmitral gradient (p < 0.025) and greater percentage change in mitral valve area (p < 0.01) following balloon mitral valvotomy. Good correlation was seen between the decrease in right axis deviation of QRS axis and fall in mean pulmonary artery pressure (r = +0.56, p < 0.001) and pulmonary vascular resistance (r = +0.48, p < 0.05). Transient arrhythmias were seen in six patients. All these changes occurred within 72 hours, and in the majority of patients within 24 hours. These results demonstrate that the acute haemodynamic changes following balloon mitral valvotomy produce corresponding changes on electrocardiogram and these changes indicate a significantly greater degree of haemodynamic benefit from the procedure than when these changes are not seen.
Balloon dilatation of simple aortic coarctation in neonates and infants.
Twenty-one infants with isolated native coarctation of aorta (mean age 4.73 +/- 2.85 months, range 15 days-12 months) underwent balloon dilatation in the last seven years at our institute. Seven of them were less than three months and 14 were older than three months. The procedure was successful in relieving the coarctation (gradient < 20 mm Hg) in five of seven (71%) infants up to three months and 12 of 14 (86%) above three months. Peak systolic gradients decreased from 70.8 +/- 20.1 to 14.5 +/- 11 mm Hg in the younger infants and from 47.7 +/- 11.7 to 11.4 +/- 9.9 mm Hg in infants above three months. Post-dilatation angiogram showed the coarctation segment to be equal to the isthmus in both the groups, 0.96 +/- 0.14 and 0.96 +/- 0.12 respectively. One three months old infant died immediately after a successful dilatation possibly due to coronary embolism, and another neonate died a few days later of unrelated pre-existing septicemia. Left ventricular function improved in all the infants with depressed preprocedure ejection fraction. Restenosis defined as peak instantaneous echo-Doppler gradient above 20 mm Hg with a significant narrowing on two-dimensional echocardiography occurred in all the five infants up to three months over a period of 1 to 12 months. Follow-up information over a period of 4 to 24 months was available in 11 of 14 older infants of which three had restenosis. Gradients progressively increased in all the four infants (2 of either group) with an initial partially successful result. A small isthmus relative to the descending thoracic aorta at diaphragm is an important predictor of restenosis/inadequate result. This discrepancy was seen much more in smaller infants, post-dilatation coarctation index being 0.68 +/- 0.11 vs 0.81 +/- 0.16 (p = 0.07). Four of the infants underwent a repeat successful dilatation. Balloon dilatation is safe and effective in infants above three months of age. In infants up to three months the procedure is feasible and leads to improvement in left ventricular function, but restenosis occurs rapidly in all of them.
Isolated iliac artery aneurysm: treatment by percutaneous stent-graft placement.
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Magnetic resonance imaging features of submitral left ventricular aneurysm.
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Dendritic cells augment granulocyte-macrophage colony-stimulating factor (GM-CSF)/herpes simplex virus thymidine kinase-mediated gene therapy of lung cancer.
Lung cancer, the leading cause of cancer death in the United States, is resistant to most currently available therapies. To evaluate a multicomponent gene therapy approach that replaces tumor-bearing host immune deficits, we genetically modified Line 1 (L1C2), a weakly immunogenic alveolar cell carcinoma cell line. L1C2 was transduced ex vivo with a retroviral construct that contained two components: a cytokine gene (granulocyte-macrophage colony-stimulating factor) and a drug sensitivity gene (herpes simplex virus thymidine kinase). The third component of this therapy, in vitro-activated syngeneic bone marrow-derived dendritic cells, was included to augment antigen presentation. The addition of ganciclovir (GCV) caused the lysis of transduced tumor cells, resulting in the release of potential tumor antigens. Ex vivo-transduced tumor cells regressed in vivo following GCV therapy but were not effective in the treatment of established parental tumors. To treat established tumors, dendritic cells were administered in combination with transduced tumor cells and GCV. A total of 50% of these mice rejected the 5-day-old established tumors and were immune to rechallenge with parental L1C2 cells. Thus, this multicomponent gene therapy system leads to both the regression of established tumors and enhanced immunogenicity in this weakly immunogenic murine lung cancer model.