Prediction of coronary events following myocardial infarction using a discriminant function analysis

This study was undertaken to derive an index for predicting coronary events in the first year after a myocardial infarction in "low-risk" patients enrolling in a Cardiac Rehabilitation Program. Data from 145 consecutive patients were analysed. The events were classified as follows: angina requiring further therapy, re-infarction and coronary death. Seventy patients had events: Angina--52, Re-infarction--8, Coronary Death--10. A discriminant function analysis was performed to predict such events using data available at the time of discharge from hospital. The following were significant predictors: (1) previous infarction/angina, (2) radiological evidence of cardiomegaly or lung congestion in the Coronary Care Unit, (3) Non-Q wave infarction and (4, 5 and 6) angina, atrial arrhythmias and a decrease in R wave amplitude in V5 during a pre-discharge exercise test. The jack-knife method classified correctly 71.2% of those with events and 72.6% of those without events. In patients with discriminant scores greater than +0.2, 82% developed events.     

Morphological analysis of cementoenamel junction in premolars of Sri Lankans

Anatomical Science International - Cementoenamel junction is an anatomical landmark which indicates the meeting point of enamel of the crown and the cementum of the root. It is an important...     

Endothelium-dependent relaxation in experimental atherosclerosis in the rabbit

The effect of feeding a diet supplemented with lipids and containing 2% cholesterol on the endothelium-dependent relaxation of rabbit aorta to acetylcholine was assessed. The effect of feeding a standard rabbit diet after an initial period of 2% cholesterol feeding was assessed also. Age-matched male, New Zealand white rabbits were fed either a 2% cholesterol diet or a standard rabbit diet. The animals were anesthetized with pentobarbitone sodium (25 mg/kg) and killed either at the beginning of the study (0 weeks) or at 4, 8, or 10 weeks. The animals in the reversal study were fed the 2% cholesterol diet for 6 weeks and killed after an additional 14 and 32 weeks on standard diet. The extent of atherosclerosis in the aorta was assessed by Sudan Red staining, estimation of tissue cholesterol, and light and electron microscopy. The relaxation response to acetylcholine was measured in rings of the thoracic aorta following precontraction with norepinephrine (-6.0 log mol/l). The relaxation was significantly impaired in aortas from rabbits fed the 2% cholesterol diet compared to aortas from animals fed the standard diet. The impairment of relaxation was apparent as early as 4 weeks after the start of the 2% cholesterol diet and remained impaired over the next 6 weeks. No improvement in endothelium-dependent relaxation was seen in rabbits on the reversal diet for 14 and 32 weeks. Thus, endothelium-dependent relaxation is attenuated in animals fed a 2% cholesterol diet, and the loss of relaxation persists for at least 32 weeks after the animals are returned to a standard diet.     

A clinical study of dry socket in Sri Lanka

An investigation into the incidence and other features of dry socket in Sri Lanka was considered worthwhile as working conditions, general health of patients and related factors may be different in developing countries. The present study was conducted at two institutes which provide differing facilities and conditions. The overall incidence was found to be 3.5% which is similar to figures reported in the U.K. and Europe. The pattern of dry socket as seen at the two institutes regarding delayed onset, lower molar site specificity, female predominance and relation to difficulty of extraction was similar to each other and to those described in previous studies. These findings support a multifactorial aetiology as does a review of the recent literature.     

The bisphosphonate zoledronic acid impairs Ras membrane [correction of impairs membrane] localisation and induces cytochrome c release in breast cancer cells

Bisphosphonates are well established in the management of cancer-induced bone disease. Recent studies have indicated that these compounds have direct inhibitory effects on cultured human breast cancer cells. Nitrogen-containing bisphosphonates including zoledronic acid have been shown to induce apoptosis associated with PARP cleavage and DNA fragmentation. The aim of this study was to identify the signalling pathways involved. Forced expression of the anti-apoptotic protein bcl-2 attenuated bisphosphonate-induced loss of cell viability and induction of DNA fragmentation in MDA-MB-231 cells. Zoledronic acid-mediated apoptosis was associated with a time and dose-related release of mitochondrial cytochrome c into the cytosol in two cell lines. Rescue of cells by preincubation with a caspase-3 selective inhibitor and demonstration of pro-caspase-3 cleavage products by immunoblotting suggests that at least one of the caspases activated in response to zoledronic acid treatment is caspase-3. In both MDA-MB-231 and MCF-7 breast cancer cells, zoledronic acid impaired membrane localisation of Ras indicating reduced prenylation of this protein. These observations demonstrate that zoledronic acid-mediated apoptosis is associated with cytochrome c release and consequent caspase activation. This process may be initiated by inhibition of the enzymes in the mevalonate pathway leading to impaired prenylation of key intracellular proteins including Ras.     

Responses of airway rapidly adapting receptors to bradykinin before and after administration of enalapril in rabbits.

1. The present study was performed in anaesthetized, artificially ventilated, open-chested rabbits to examine whether (a) the rapidly adapting receptors of the airways were stimulated by exogenously administered bradykinin, and (b) if this sensitivity could be enhanced by the angiotensin-converting-enzyme inhibitor, enalapril. 2. Rapidly adapting receptor activity (n = 8) was recorded from the cervical vagus. Bradykinin was injected intravenously (0.25-1.0 microgram/kg) and a dose-response curve relating receptor activity to bradykinin was elicited. In the control state, the threshold dose of bradykinin required for stimulation of rapidly adapting receptors was 0.53 +/- 0.11 microgram/kg. Five minutes after the administration of enalapril maleate (2 mg intravenously), the dose-response curve was shifted to the left significantly (P < 0.01). 3. In seven other rapidly adapting receptors, enalapril (2 mg) increased the resting activity significantly (P < 0.05) over a period of 60 min. This increase was significantly different from the spontaneous variation in neural activity of rapidly adapting receptors (n = 7) recorded over a period of 60 min. 4. Bradykinin either alone (0.25-1.0 microgram/kg) or in the presence of enalapril did not stimulate the slowly adapting receptors (n = 5) of the airways. 5. These results show that (a) exogenous bradykinin stimulates the rapidly adapting receptors, (b) the sensitivity of rapidly adapting receptors to bradykinin is enhanced by enalapril and (c) enalapril increases the resting activity of rapidly adapting receptors. It is suggested that the cough reported after the administration of enalapril may be due to stimulation of rapidly adapting receptors of the airways.