A simplified radiometric assay for plasma norepinephrine and epinephrine.

Obesity is a significant health and social problem which has reached pandemic levels. The obesogenicity of an environment has been defined as ‘the sum of influences that the surroundings, opportunities, or conditions of life have on promoting obesity in individuals or populations’.1 Prevention and treatment of obesity has focused on pharmacological, educational and behavioural interventions, with limited overall success. A novel and a longer-term approach would be to investigate the environments that promote high energy intake and sedentary behaviour; this has not yet been fully understood. The obesity epidemic has attracted attention at all levels, from general media interest to policy and practice from health and other professions including urban designers and planners. Shaping the environment to better support healthful decisions has the potential to be a key aspect of a successful obesity prevention intervention. Thus in order to develop effective environmental interventions, in relation to obesity, w...

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Obesogenic environments: exploring the built and food environments

Resting hemodynamic measurements and plasma levels of catecholamines and renin activity were studied in 55 hospitalized treated patients with congestive heart failure in clinically stable condition. Plasma norepinephrine (mean ± standard error of the mean 594 ± 51 pg/ml, range 153 to 1,868) and plasma renin activity (mean 12.9 ± 2.4 ng/ml per hr, range 0.6 to 85.2) values were significantly (probability [p] It is concluded that patients with congestive heart failure can be categorized on the basis of neurohumoral activity. The statistically significant correlations between plasma norepinephrine and hemodynamic evidence of cardiac dysfunction suggest that the sympathetic response is either a marker of or a contributor to the hemodynamic derangement. Because hemodynamic abnormalities did not correlate with plasma renin activity despite a statistically significant correlation between plasma norepinephrine and plasma renin activity, it appears that the two systems are independently activated in congestive heart failure but that sympathetic stimulation may be one factor contributing to renin release. Further studies are needed to assess the usefulness of plasma hormone levels in evaluating and treating patients with congestive heart failure.

Activity of the sympathetic nervous system and renin-angiotensin system assessed by plasma hormone levels and their relation to hemodynamic abnormalities in congestive heart failure☆

Use of plasma norepinephrine for evaluation of sympathetic neuronal function in man.

The view from the road: implications for stress recovery and immunization

Validity of plasma-catecholamine estimations

Electrocardiograms were recorded in experienced motor-car drivers accustomed to busy city traffic while driving their own cars along familiar routes. The majority with normal hearts or a history of coronary heart disease increased their heart rates; brief periods when the rate exceeded 140/min. were recorded in both groups. ST changes not caused by tachycardia developed in 3 out of 32 normal drivers. Of 24 drivers with coronary heart disease 13 increased their ST and T abnormalities, the changes being gross in six. A further five developed multiple ventricular ectopic beats. Two coronary drivers experienced anginal pain and two left ventricular failure. Healthy motor-racing drivers increased their heart rates to 180/min. in the few minutes before the start of a race and to above 200/min. while racing.Little or no change in the plasma catecholamine levels was noted in three coronary subjects immediately after a city drive compared with resting levels. All the racing drivers showed a considerable increase in noradrenaline, and in one instance adrenaline, immediately after racing.Persons in whom angina is easily provoked when driving or who are in borderline left ventricular failure should be advised not to drive.

Some effects of motor car driving on the normal and abnormal heart.

https://www.bmj.com/content/bmj/4/5676/130.full.pdf

Some effects of motor-car driving on the normal and abnormal heart

Paired biopsy specimens from the right or left atrial appendage have been taken from patients undergoing cardiopulmonary bypass surgery after various periods of intermittent coronary artery occlusion and analysed for potassium, sodium, and chloride content, total tissue water, and extracellular fluid volume. Tissue potassium content is reduced after coronary artery occlusion, and potassium loss bears an apparently linear relationship to the duration of occlusion. After 150 minutes of occlusion the potassium content had decreased by nearly 50%. For the first 50 minutes of occlusion the myocardial cells swelled at the expense of the extracellular fluid volume. Thereafter there was movement of water in the opposite direction, with subsequent cell shrinkage. The loss of potassium and the alteration in cellular hydration exert profound effects on the calculated gradient of potassium across the cell membrane. This is discussed in relation to the arrhythmias and low cardiac output after myocardial ischaemia. An attempt to rationalize treatment is made.

Peter Taggart

Papers

Validity of plasma-catecholamine estimations

Some effects of motor car driving on the normal and abnormal heart.

Some effects of motor-car driving on the normal and abnormal heart

Significance of potassium in genesis of arrhythmias in induced cardiac ischaemia.

Addressing a medical meeting: effect on heart rate, electrocardiogram, plasma catecholamines, free fatty acids, and triglycerides.