Aortic valve disease and left dominant coronary system a significant association.

OBJECTIVES: To study the dominance of coronary artery distribution in patients with aortic valve disease. MATERIAL AND METHODS: The prevalence of left dominant coronary artery system in patients with aortic valve disease was compared with patients without aortic valve disease undergoing coronary angiography. Group 1 consisted of 237 patients with symptomatic aortic valve disease and Group 2 consisted of 241 consecutive patients without aortic valve disease undergoing cardiac catheterisation. RESULTS: Forty two patients in Group 1 and 20 patients in Group 2 (p < 0.01) showed a left dominant pattern of supply. Fifteen patients in Group 1 and eight patients in Group 2 showed a co-dominant pattern of supply (p = NS). Among patients in Group 1, there was no significant difference in the increased prevalence of left dominant system between patients with congenital or acquired aortic valve disease or between the different categories of aortic valve lesions. CONCLUSION: Patients with aortic valve disease show a statistically significant higher prevalence of left dominant pattern of blood supply. This higher prevalence of left dominance is seen in all categories of aortic valve lesions, namely, predominant aortic stenosis, predominant aortic regurgitation and in combined aortic stenotic and regurgitant lesions.

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.

Hypoglycemic activity of Swertia chirayita (Roxb ex Flem) Karst.

Hexane fraction of S. chirayita (250 mg/kg body wt.) induced significant fall in blood sugar and significant increase in plasma IRI simultaneously after single oral administration without influencing liver glycogen concentration in albino rats. On the other hand, daily administration for 28 days resulted in significant lowering of blood sugar and increase in plasma IRI along with a significant rise in liver glycogen. Intestinal absorption of glucose was not inhibited by hexane fraction. It is suggested that hexane fraction of S. chirayita possibly acts through its insulin releasing effect.

Blood sugar lowering potentiality of selected Cucurbitaceae plants of Indian origin.

Using five experimental models, the blood sugar lowering efficacy of eight plants of Cucurbitaceae family has been assessed. The ethanolic extract of Cucumis sativus Linn, Cucumis melo utilissimum Roxb, Cucumis melo Linn, Benincasa hispida Thunb Cogn and Tricosanthes anguina Nees, when administered in 250 mg/kg dose, orally to rats failed to lower blood sugar or to depress the peak value, after glucose load. However, ethanolic extract of Momordica charantia Linn plant and Coccinia indica Whit and Arn root significantly lowered blood sugar in fasted model and depressed the peak value in glucose loaded model. Ethanolic extract of Tricosanthes dioica Roxb plant caused a significant lowering of blood sugar in fasted rats and depressed the peak value in glucose loaded single and longterm fed groups of rats. The ethanolic extract of the aerial part of T. dioica also induced significant depression in the peak values in the glucose loaded models.

Effects of prednisolone and dexamethasone on (pro)insulin biosynthesis and insulin release by rat islets of Langerhans.

Administration of either prednisolone or dexamethasone (10 mg/kg body wt/day/oral) to rats for 21 days resulted in inhibition of (pro)insulin biosynthesis and immunoreactive insulin release by isolated islets. A gradual reversal of prednisolone's effect was obtained after exposing islets to increasing glucose concentrations but glucose challenges failed to influence dexamethasone's effect.

Changes in pancreatic beta cell function during growth and reproductive maturity of rats.

An attempt has been made to study the changes, if any, in the efficiency of pancreatic beta cell function at different ages using one experimental model. For this, pancreatic islets were isolated from albino rats of 3, 8, 12 and 36 weeks of age and challenged with various concentrations of glucose (11.0, 16.7 and 22.2 mM). Significantly higher rate of glucose stimulated (pro)insulin biosynthesis was seen in the islets from 3 week old rats as compared to the islets obtained from 8, 12 and 36 week rats. On the other hand, immunoreactive insulin release was observed to be highest from islets of 8 week old rats followed by that of 12, 36 and 3 week old ones.

Anti-secretagogue effect of lithium on isolated rat islets of Langerhans.

Administration of lithium carbonate solution (50 mg/kg, po, twice daily) to Charles Foster male albino rats for 45 consecutive days caused an intolerance to oral glucose. Inhibition in (pro)insulin biosynthesis followed by a significant fall in immunoreactive insulin release was seen in islets isolated from identically treated rats. As the activities of acid phosphatase and cathepsin B were unaltered, it is possible that the anti-secretagogue effect is sequential to inhibition of (pro)insulin biosynthesis by lithium.