Cerebral activations during viewing of food stimuli in adult patients with acquired structural hypothalamic damage: a functional neuroimaging study.

BACKGROUND/OBJECTIVES: Obesity is common following hypothalamic damage due to tumours. Homeostatic and non-homeostatic brain centres control appetite and energy balance but their interaction in the presence of hypothalamic damage remains unknown. We hypothesized that abnormal appetite in obese patients with hypothalamic damage results from aberrant brain processing of food stimuli. We sought to establish differences in activation of brain food motivation and reward neurocircuitry in patients with hypothalamic obesity (HO) compared with patients with hypothalamic damage whose weight had remained stable. SUBJECTS/METHODS: In a cross-sectional study at a University Clinical Research Centre, we studied 9 patients with HO, 10 age-matched obese controls, 7 patients who remained weight-stable following hypothalamic insult (HWS) and 10 non-obese controls. Functional magnetic resonance imaging was performed in the fasted state, 1 h and 3 h after a test meal, while subjects were presented with images of high-calorie foods, low-calorie foods and non-food objects. Insulin, glucagon-like peptide-1, Peptide YY and ghrelin were measured throughout the experiment, and appetite ratings were recorded. RESULTS: Mean neural activation in the posterior insula and lingual gyrus (brain areas linked to food motivation and reward value of food) in HWS were significantly lower than in the other three groups (P=0.001). A significant negative correlation was found between insulin levels and posterior insula activation (P=0.002). CONCLUSIONS: Neural pathways associated with food motivation and reward-related behaviour, and the influence of insulin on their activation may be involved in the pathophysiology of HO.

Implementation of regulations and promotion of standards for protective measures in the absence of statutory regulations.

Asbestos regulations in the UK and several other countries are described, and it is suggested that these could be used as a basis for similar regulations in other countries which do not yet have them. Those aspects of the UK regulations which make them particularly applicable to all occupational situations in which asbestos dust might be emitted are listed. As a result of such regulations, standards of control have improved; two examples are given.

Effect of changed working techniques on asbestos dust levels in the working environment.

The methods are presented for correcting the working environment when asbestos dust concentrations are too high. Asbestos dust, being fibrous, remains suspended longer than most industrial dusts, and has a tendency to pack and cling together. Sophisticated monitoring techniques have made possible the attainment of standards that are effective in controlling risks of asbestos related diseases. The most difficult situation to control is the dust produced in stripping old asbestos lagging, but predamping has greatly reduced the contamination. Special attention has been paid to the special needs of people working with asbestos on building sites. Special hoods have been designed to protect workers drilling, cutting and sanding asbestos material. The Environmental Control Committee has prepared a series of Control and Safety Guides and a Code of Practice for the Disposal of Asbestos Waste Material as part of activities to promote new and improved methods of dust control.