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Biomedical subjects

J Dhawan

Publications and source records attributed to J Dhawan.

24 records · Page 2Linked to original sources
PubMed1991

Paucity of risk factors in women with angina and normal coronary angiograms.

A significant proportion of women who undergo coronary arteriography for investigation of angina have normal coronary angiograms. We wanted to test the hypothesis that screening women with risk factors for coronary arterial disease would reduce the need for subjecting them to this invasive procedure. Comparisons were made between 100 women with normal coronary angiograms and 100 women with angiographic evidence of coronary arterial disease. Both groups had presented with angina and had undergone coronary angiography in 1985 or 1986. Women with angina and normal coronary angiograms had fewer risk factors than those with coronary arterial disease. They were younger (mean 49.0 and 55.9 years, respectively), had less severe angina on presentation (atypical or mild angina: 35% vs 16%), were less likely to have a family history of myocardial infarction (12% vs 53%), were more likely to have never smoked cigarettes (64% vs 13%), and fewer of them had a serum cholesterol in excess of 6 mmol/l (36% vs 64%). Five independent predictors of coronary arterial disease were identified; family history, myocardial infarction, age, hypertension and smoking habit. No women with angina and abnormal coronary angiograms were found to be free of risk factors, whereas 42% of women with angina and normal coronary angiogram were free of risk factors. The data suggests that coronary angiography will probably be normal in women with angina who are free of risk factors.

Adult↗
PubMed1990

Regulation of alpha 1 (I)-collagen gene expression in response to cell adhesion in Swiss 3T3 fibroblasts.

Nonadhesive conditions cause Swiss 3T3 fibroblasts to enter a quiescent state that is reversed upon reattachment to a surface. Previously, we demonstrated that adhesion in serum-free conditions is sufficient to activate suspension-arrested cells out of Go, with the induction of the growth-associated genes, c-fos, c-myc, and actin. In this study, we have employed this system to identify programs of gene expression that respond primarily to the adhesive state of the cell, rather than the growth state. We show that cells in different adhesive states can be distinguished by their patterns of protein synthesis. Analysis of one adhesion-responsive protein led to its identification as pro-alpha 1 (I)-collagen. Pro-alpha 1 (I)-collagen synthesis and mRNA levels are decreased up to 6-fold in suspension-arrested fibroblasts, but are enhanced up to 5-fold as cells approach confluence. This suggests that the reduced expression in suspension-arrested cells is not simply a result of quiescence. In addition, reattachment of suspended cells in serum-free conditions caused a 7-fold induction of collagen mRNA levels and a greater than 20-fold rise in the rate of procollagen synthesis. The expression of c-myc was induced during adhesion in serum-free medium as well as by serum addition to suspension-arrested cells. However, alpha 1 (I)-collagen gene expression was unaffected by serum in the absence of adhesion. These results indicate that collagen gene expression is directly responsive to cell adhesion, independent of the growth state.

Animals↗
PubMedDate not supplied

Safety and predictive value of exercise stress testing within three days after percutaneous transluminal coronary angioplasty.

The safety and efficacy of exercise stress testing within three days of successful coronary angioplasty was evaluated in 226 patients with coronary artery disease; 137 patients had single-vessel disease (SVD) and 89 had multi-vessel disease (MVD). Comparisons were made between patients with SVD and MVD and between patients whose vessels restenosed and those whose vessels remained patent. The post-angioplasty exercise test was positive in 48% of SVD and 49% of MVD patients. However, a positive result did not predict future restenosis. There was a significantly [p = 0.004] higher proportion of patients in the MVD group, compared with the SVD group, who exhibited greater than or equal to 2mm ST-depression, but again this was not indicative of restenosis. No complications as a direct result of having an early exercise test occurred. Exercise stress testing proved safe and was effective in demonstrating relief from angina in most patients early after coronary angioplasty. It did not, however, predict restenosis.

Adult↗