Does dietary fat influence insulin action?

What is clear from the research thus far is that dietary fat intake does influence insulin action. However, whether the effect is good, bad, or indifferent is strongly related to the fatty acid profile of that dietary fat. The evidence has taken many forms, including in vitro evidence of differences in insulin binding and glucose transport in cells grown with different types of fat in the incubation medium, in vivo results in animals fed different fats, relationships demonstrated between the membrane structural lipid fatty acid profile and insulin resistance in humans, and finally epidemiological evidence linking particularly high saturated fat intake with hyperinsulinemia and increased risk of diabetes.

Comparison between manual and semiautomated analysis of left ventricular volume parameters from short-axis MR images.

Purpose: The goal of this study was to evaluate a newly developed semiautomated contour detection algorithm for the quantitative analysis of cardiovascular MRI.

Method: Left ventricular function parameters derived from automatically detected endocardial and epicardial contours were compared with results derived from manually traced contours in short-axis multislice GRE MRI studies of 10 normal volunteers and 10 infarct patients.

Results: Compared with manual image analysis, the semiautomated method resulted in the following systematic and random differences (auto-manual; mean +/- SD): end-diastolic volume: -5.

Beneficial effect of enalapril on left ventricular remodelling in patients with a severe residual stenosis after acute anterior wall infarction.

Objective: The present study was designed to evaluate the effects of early angiotensin converting enzyme (ACE) inhibition on left ventricular enlargement in patients with anterior wall infarction following reperfusion therapy.

Methods: Seventy-one consecutive patients with an anterior wall myocardial infarction were randomly allocated to enalapril (n = 36) or placebo (n = 35). All patients received either thrombolytic therapy (n = 46) or underwent primary coronary angioplasty (n = 25).

Skeletal muscle triglyceride levels are inversely related to insulin action.

In animal studies, increased amounts of triglyceride associated with skeletal muscle (mTG) correlate with reduced skeletal muscle and whole body insulin action. The aim of this study was to test this relationship in humans. Subjects were 38 nondiabetic male Pima Indians (mean age 28 +/- 1 years).

Detection and quantification of dysfunctional myocardium by magnetic resonance imaging. A new three-dimensional method for quantitative wall-thickening analysis.

Background: Regional left ventricular dysfunction is a major consequence of myocardial ischemia, and its extent determines long-term prognosis. Accurate and reproducible analysis of left ventricular dysfunction is therefore useful for risk stratification and patient management.

Methods And Results: Short-axis cardiac cine magnetic resonance (MR) imaging was performed in 25 patients after anterior myocardial infarction at 21 +/- 2.

Reproducibility of left ventricular size, shape and mass with echocardiography, magnetic resonance imaging and radionuclide angiography in patients with anterior wall infarction. A plea for core laboratories.

After myocardial infarction, left ventricular volume and ejection fraction can be assessed by echocardiography, magnetic resonance imaging and radionuclide angiography to guide therapy and determine prognosis. Whether a measured parameter gives the same results irrespective of the method used and the observer who performs the analysis is only partly known. Intra-observer and inter-observer variability were determined for echo and magnetic resonance imaging.

Regional myocardial shape alterations in patients with anterior myocardial infarction.

Objective: To assess the impact of regional left ventricular curvature in patients with an acute anterior myocardial infarction on ventricular volume.

Methods: Left ventricular curvature was calculated at 100 points from apical four chamber echocardiograms of 68 patients with an acute anterior wall infarction. Curvature at any point of the contour was defined as the reciprocal of the radius of the circle that intersects that point tangentially and was independent of volume and geometric assumptions.

Interrelationships between muscle morphology, insulin action, and adiposity.

There is evidence that insulin resistance and obesity are associated with relative increases in the proportion of glycolytic type IIb muscle fibers and decreases in the proportion of oxidative type I fibers. Futhermore, insulin resistance and obesity are associated with the fatty acid (FA) profile of structural membrane lipids. The present study was undertaken to define interrelationships between muscle fiber type and oxidative capacity, muscle membrane FA composition, and insulin action and obesity.

Adiposity and body mass indices in children: Benn's index and other weight for height indices as measures of relative adiposity.

Objectives: Several forms of weight for height or body mass index (BMI) are in widespread epidemiological and clinical use as measures of relative adiposity. The form derived by Benn for adults has been advocated for use in children and practical aspects of this proposition are considered.

Methods: Height and weight data from 8492 Australian schoolchildren aged 7 to 15 were studied.

Changes in glucose and lipid metabolism following weight loss produced by a very low calorie diet in obese subjects.

Objective: To study the effects of a very low calorie diet (VLCD) on glucose and lipid metabolism in obese subjects, in particular, the effects on insulin sensitivity and the activities of the key enzymes of glucose disposal, glycogen synthase (GS) and the pyruvate dehydrogenase complex (PDHC).

Design: Clinical dietary intervention study (1.67 MJ (400 kcal)/day) until weight loss of > 10%.

Body mass index in screening for adiposity in children and adolescents: systematic evaluation using receiver operating characteristic curves.

Body mass index (BMI) has been recommended for use in adolescent screening programs to select subjects with excess body fat for appropriate interventions. No systematic evaluation of MBI in screening for high degrees of adiposity was available when these recommendations were formulated. The purpose of this paper was to evaluated the screening performance of BMI using appropriate epidemiologic methods.

Assessment of left ventricular volume and mass by cine magnetic resonance imaging in patients with anterior myocardial infarction intra-observer and inter-observer variability on contour detection.

Remodeling of the left ventricle after myocardial infarction can be documented by calculation of left ventricular volume and mass, using endocardial and epicardial tracings of multilevel multiphase short-axis cine magnetic resonance (MR) imaging series. We assessed left ventricular volume and mass from 8 slices and during 12 phases of the cardiac cycle in seven patients with an anterior wall myocardial infarction; one patient was studied twice, leaving eight MR examinations to be evaluated. Purpose of this study was to assess the intra-observer and inter-observer variability of epicardial volume, endocardial volume, and left ventricular mass from contours manually traced by two independent observers.

Skeletal muscle membrane lipids and insulin resistance.

Skeletal muscle plays a major role in insulin-stimulated glucose disposal. This paper reviews the range of evidence in humans and experimental animals demonstrating close associations between insulin action and two major aspects of muscle morphology: fatty acid composition of the major structural lipid (phospholipid) in muscle cell membranes and relative proportions of major muscle fiber types. Work in vitro and in vivo in both rats and humans has shown that incorporation of more unsaturated fatty acids into muscle membrane phospholipid is associated with improved insulin action.

Head-to-head comparison of 201Tl rest-redistribution scintigraphy and stress-immediate reinjection scintigraphy in the detection of myocardial viability.

Reinjection imaging with thallium-201 (201Tl) provides a reliable method of identifying viable myocardium. Reinjection of 201Tl immediately after completing the stress images followed by imaging 1 h after reinjection shortens the examination time to a maximum of 2.5 h and provides an alternative imaging approach in patients with coronary artery disease.

Body protein in prepubertal children with phenylketonuria.

Objective: To assess body protein and protein deposition in prepubertal children with phenylketonuria (PKU).

Design: Cross-sectional study with nested longitudinal cohort.

Setting: A tertiary referral paediatric hospital.

Skeletal muscle membrane lipid composition is related to adiposity and insulin action.

The cellular basis of insulin resistance is still unknown; however, relationships have been demonstrated between insulin action in muscle and the fatty acid profile of the major membrane structural lipid (phospholipid). The present study aimed to further investigate the hypothesis that insulin action and adiposity are associated with changes in the structural lipid composition of the cell. In 52 adult male Pima Indians, insulin action (euglycemic clamp), percentage body fat (pFAT; underwater weighing), and muscle phospholipid fatty acid composition (percutaneous biopsy of vastus lateralis) were determined.

Relationships between muscle membrane lipids, fiber type, and enzyme activities in sedentary and exercised rats.

Insulin resistance in skeletal muscle is associated with 1) relative increases in the proportion of glycolytic and fast-twitch muscle fibers and decreases in the proportion of more oxidative fibers and 2) a higher proportion of the saturated fatty acids in membrane structural lipids. Exercise is known to improve insulin action. The aims of the current studies were 1) to investigate the relationship between muscle fiber type and membrane fatty acid composition and 2) to determine how voluntary exercise might influence both variables.

Regional diastolic wall motion dynamics in anterior myocardial infarction: analysis and quantification with magnetic resonance imaging.

Background: Regional variability in systolic and diastolic cardiac function occurs in most cardiac disorders. The influence of this regional functional heterogeneity on global function is not well understood and is difficult to study with the common imaging modalities.

Methods: A midventricular short axis slice of the left ventricle was obtained with ECG-triggered magnetic resonance imaging in eight infarct patients and 10 control volunteers.

Recommended body mass index cutoff values for overweight screening programmes in Australian children and adolescents: comparisons with North American values.

Objective: Guidelines for screening children and adolescents for overweight have recently been published by a North American Expert Committee. As Australian clinicians might uncritically adopt these recommendations, we explore the consequences of applying North American body mass index (BMI) cutoff values to an Australian population.

Methodology: The Australian BMI cutoffs were calculated using the methods recommended from height and weight data for 8492 schoolchildren aged 7-15 years old.

Body composition measurement in normal children: ethical and methodological limitations.

There are significant ethical. practical and theoretical issues that need to be considered when measuring body composition in normal children. For example, when evaluating the use of techniques that involve ionizing radiation, then the benefit to the volunteer subject, or society at large, needs to be balanced against the likely harm to the subject.

Combining salicylate and enalapril in patients with coronary artery disease and heart failure.

Objective: To study the effects of adding a salicylate to the angiotensin converting enzyme inhibitor enalapril in patients with heart failure due to coronary artery disease.

Design: Double blind, crossover study for three days in hospital followed by an extended similar study outside hospital over two months of once daily enalapril plus salicylate and enalapril plus placebo.

Setting: Tertiary referral centre.

Total body nitrogen in children with chronic renal failure and short stature.

Objective: To directly assess the body protein content of children with chronic renal failure (CRF) and short stature.

Setting: A tertiary referral paediatric hospital.

Subjects: There were: (i) 17 patients (10 male, nine pre-pubertal; mean age 12.