Biomedical subjects
John Monro
Publications and source records attributed to John Monro.
Expressing the glycaemic potency of foods.
The glycaemic index (GI) was introduced to guide food exchanges within equicarbohydrate food categories, and it expresses the glycaemic potency of the available carbohydrate component in a food relative to that of glucose. As GI is a relative value based on 'available carbohydrate' it cannot guide food choice for glycaemic control unless the foods are equal in available carbohydrate. Furthermore, GI cannot respond to food intake or to effects on food glycaemic potency of replacing glycaemic ingredients with non-glycaemic ingredients. The glycaemic glucose equivalent (GGE) overcomes these limitations of GI. The GGE content of an amount of food is the weight of glucose (g) that would induce a glycaemic response equal to that induced by the food. Few studies have compared GI and GGE as guides to food choice for glycaemic control, but in a direct test of the predictive validity of GGE in a group of foods of differing carbohydrate and GI, GGE predicted glycaemic potency well, whereas GI was unrelated to glycaemic effect. Furthermore, an information-processing model of the use of food information in food choice shows that GI has fundamental flaws when used outside the restriction of equicarbohydrate food exchange categories. As a general guide to food choices for the control of glycaemia GI does not satisfy the criteria predictive validity, accuracy, safety, ease of use, flexibility, sufficiency and compatability, whereas GGE does. GGE is also a scientifically precise and meaningful term with which to express glycaemic potency than is 'glycaemic load'.
Surgical treatment of infective endocarditis.
OBJECTIVE: The objective of this study is to determine the surgical indication in the treatment of infective endocarditis. SETTING: Retrospective study in a tertiary care--Wessex Cardiothoracic--Centre. SUBJECTS AND DESIGN: Case records of patients admitted with infective endocarditis for surgical treatment between 1984 to 1994 at Wessex Cardiothoracic Centre were analysed. This analysis includes the age, sex, microbiology results, risk factors, surgical indication and early results. RESULTS: A total of 123 patients was admitted with bacterial endocarditis treated surgically since 1984. The mean age was 51.9 years with male:female ratio of 3:1. The most common causative organism was streptococcus (63%) and staphylococcus (30%). Native valve endocarditis occurred in 111 patients, affecting the aortic, mitral, combined aortic and mitral valve in 69%, 33%, and 8% of cases, respectively. Late prosthetic valve endocarditis occurred in 12 patients. The most common indication for surgery was heart failure (84%), uncontrolled sepsis (8%), and recurrent endocarditis (2.5%). Hospital mortality was 1.6%. Complete heart block and cerebrovascular accident developed in 4% and 2.4%, respectively. CONCLUSIONS: Heart failure is the main indication for surgery. Valve replacement with mechanical prosthesis is a safe procedure with a low rate of mortality and complication.
Redefining the glycemic index for dietary management of postprandial glycemia.
The glycemic index (GI) is a component-referenced index, defined as the effect on blood glucose of glycemic carbohydrate in a food as a percentage of the effect of an equal amount of glucose. GI is not suitable for dietary management of postprandial glycemia because it refers to glycemic carbohydrate, not to food, it is static, i.e., unresponsive to intake, and it is relative in that it can be used appropriately only for equicarbohydrate comparisons. Food values for dietary management, in contrast, must be food-based, intake responsive and sensitive to variations in composition typical of diets. The limitations of GI could be overcome by expanding its definition beyond glycemic carbohydrate, to foods. GI could then be used as a food-referenced index, expressed as glycemic glucose equivalents (GGE)/100 g food, and extrapolated to GGE per common standard measure (CSM) as a value for the glycemic load exerted by familiar food quantities. GI(food) and GGE/CSM would then be expressed as are nutrients in food composition databases, would lie on the same quantity-dependent continuum and could be used with nutrient information to provide a more complete nutritional profile of a food than is provided by nutrients alone. GI would then be a practical adjunct to food composition data, which was its intended role.