These data indicate that medial calcification in MS lesions is an active process potentially orchestrated by phenotypically modified VSMCs.

showed no response to naloxone. Three months later he was admitted in respiratory failure refractory to all treatment. Necropsy showed chronic bronchitis, bullous emphysema, and right ventricular hypertrophy. The intercostal muscles were thin and fibrous, and histology of these and the diaphragm and psoas showed changes of chronic denervation. Histology of the spinal cord was not obtained. DiscussionNaloxone reverses the apnoeic response to hypoxia in neonatal rabbits2 but, even in large doses, has no effect on respiration in hypoxic man.' Respiratory failure in this patient was thought to be caused by a combination of chronic airflow obstruction and weakness of the respiratory muscles (possibly due to chronic spinal muscular atrophy).4 Intravenous naloxone produced an increase in minute ventilation and general agitation when he was acutely ill. The increase in oxygen saturation was greater than expected for the increase in ventilation, suggesting improved ventilation-perfusion matching, but the response occurred only in the acute illness.These findings suggest that there may be overproduction of, or increased sensitivity to, endorphins in acute respiratory failure. Naloxone is beneficial in shock,5 the postulated mechanism being that endorphins inhibit the interaction of catecholamines with their receptors. Such an action might account for the changes in ventilation-perfusion balance in our patient. Medial arterial calcification and diabetic neuropathy M E EDMONDS, N MORRISON, J W LAWS, P J WATKINS Abstract X-ray examinations of the feet, knees, and hands were performed on 20 diabetics with severe neuropathy and 20 diabetics with no evidence of neuropathy but with a similar mean age and duration of diabetes. All were under 53 years old with no clinical evidence of peripheral vascular disease. Medial arterial calcification was much more common and extensive in the patients with neuropathy, occurring in the feet in 15 and in the hands in eight compared with in four (p <0 001) and none (p <0 001) of the controls respectively. Although there was some correlation between calcification and both proteinuria (p <0 05) and proliferative retinopathy (p <0 02), the association between calcification and neuropathy (p <0 001) was much stronger.Neuropathy, with sympathetic denervation of the smooth muscle of the tunica media, may be important in the aetiology of medial arterial calcification.

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