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Biomedical subjects

L Cope

Publications and source records attributed to L Cope.

7 recordsLinked to original sources
PubMed1995

The influence of age, liver size and enantiomer concentrations on warfarin requirements.

1. We have tested the hypothesis that the fall in hepatic mass with age influences the age related increase in sensitivity to warfarin. In 39 otherwise healthy outpatients, aged 50-87 years, stabilised on warfarin for prophylaxis of thromboembolism, age, mean International Normalised Ratio (INR), and mean warfarin dosage were recorded. Liver volume was measured by ultrasound, and plasma was assayed for trough concentrations of (R)- and (S)-warfarin. 2. There was a negative correlation between age and liver volume (r = -0.41; P = 0.01) and age and dose (r = -0.53; P = < 0.001) and a positive correlation between liver volume and dose (r = 0.49; P = 0.002). There was no significant correlation between dosage and (R)- and (S)-warfarin concentrations, nor between dosage and INR. 3. The regression model including both age and liver volume data showed a better fit for estimation of warfarin dosage requirement than regression models based on age and liver volume data alone. Ninety-five per cent prediction intervals for warfarin dose requirements were wide, whether age alone, or age and liver volume were used in calculations. 4. Due to inter-individual variation in warfarin dosage requirements related to other influences, both explained and unexplained, routine measurement of age and liver volume would not contribute further clinically useful information to that obtained by the INR test currently used for predicting warfarin dosage requirements.

Age Distribution↗
PubMed1991

Transfemoral digital subtraction aortography. Are diluted high osmolar contrast media acceptable?

The ionic monomer, sodium diatrizoate at 150 mg I/ml (726 mosmol/kg) and the non-ionic monomer, iopamidol, diluted to the same iodine concentration but at 324.3 mosmol/kg, were randomly allocated to patients undergoing transfemoral intra-arterial digital subtraction angiography for lower limb peripheral vascular disease. The agents produced images of comparable quality and diagnostic efficacy. There were no significant differences between the media regarding sensations of pain and warmth. Minor neurological symptoms (headache and dizziness) occurred 7 times more frequently with the ionic monomer. There was a slight but temporary rise in plasma potassium one hour after injection of the ionic monomer but no evidence of appreciable intravascular haemolysis. The non-ionic monomer caused a slight fall in haemoglobin and haematocrit one hour after injection which is attributed to osmotic haemodilution. It is concluded that a diluted high osmolar contrast agent is an acceptable alternative to a low osmolar agent in transfemoral digital subtraction lower limb aortography.

Adult↗
PubMed1989

Knowledge management as a decision support method: a diagnostic workup strategy application.

We have explored the potential of a computer-based approach called "knowledge management" to aid in clinical problem solving and education. The major features of the approach are its ability to support flexible and immediate access by a user to relevant knowledge and annotation and organization of the knowledge for personal use and subsequent retrieval. We illustrate this approach with its application to diagnostic workup strategy problems. In this application, knowledge may be in the form of static narrative text, diagrams, pictures, graphs, tables, flow charts, or bibliographic citations. Other more dynamic forms of knowledge may be the result of simulations, "what if" analyses or modeling, quantitative mathematical or statistical calculation, or heuristic inference. User assessment has demonstrated the system's ease of use and user perception of its desirability, but underscores the need for a "critical mass" of knowledge before such an approach will be widely utilized.

Decision Support Techniques↗
PubMed1985

Basal, sham feed and pentagastrin stimulated gastric acid, pepsin and electrolytes after omeprazole 20 mg and 40 mg daily.

Gastric secretion was measured in nine patients with duodenal ulcer before, and after treatment for four weeks with omeprazole 20 mg or 40 mg daily. Basal acidity and acid output were affected variably by 20 mg, but inhibited totally by 40 mg daily. Sham feed stimulated acid output was reduced by 20 mg daily and completely inhibited by 40 mg daily. Maximal pentagastrin stimulated acid output was halved by 20 mg omeprazole daily and 84% inhibited by 40 mg daily. The reduction in acidity was always greater than the reduction of volume. Pepsin output after pentagastrin was little altered but with the reduced secretory volume pepsin concentrations were increased by both doses. The major cause of reduced aspirate acid output after omeprazole is decreased secretion of the primary acid component of the parietal cell by the proton pump H+K+ ATPase. Duodenogastric alkaline reflux is, however, markedly increased after omeprazole and is an additional factor in the resultant hypoacidity or even anacidity after this drug.

Adult↗
PubMedDate not supplied

Iliac artery injury following placement of the memotherm arterial stent.

Iliac rupture and aneurysm formation at the site of stent placement has rarely been described in the literature. We report four cases, three of iliac rupture, including a delayed rupture, and an aneurysm, with the use of a single type of stent, the Memotherm stent. We believe the design of the stent significantly contributed to damage to the arterial wall and subsequently prevented closure of the arterial tear by balloon tamponade in the two cases where this was attempted. Two patients, one with rupture and one with an aneurysm, were successfully treated with a covered stent obviating surgery and two ruptures resulted in death. We recommend that all interventionists carrying out iliac angioplasty and/or stenting should have access to covered stents for such emergencies.

Aged↗