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Biomedical subjects

I M Stewart

Publications and source records attributed to I M Stewart.

15 recordsLinked to original sources

Relation of reduction in pressure to first myocardial infarction in patients receiving treatment for severe hypertension.

In order to examine the widely held belief that the aim of antihypertensive therapy should be to restore "normality," the relative risk of myocardial infarction and sudden death was related to the extent of pressure reduction in a survey of 169 patients with uncomplicated essential hypertension followed-up under treatment over a mean period of 6.25 years. Apart from the effects of the hypotensive agents, there were no statistically significant differences in coronary heart-disease (C.H.D.) risk factors between the patients who had and those who did not have an infarction. Overall average values for final diastolic pressure (F.D.P.), as last recorded before the end of the study, were almost the same in the two groups. But the relative risk of myocardial infarction in the patients with F.D.P. reduced to less than 90 mm Hg was more than five times that in the patients with F.D.P. 100--109 mm Hg (P less than 0.01), while in those who had developed infarcts with F.D.P.S of less then or equal to 90 mmHg the pressure falls were all markedly greater than in unaffected controls matched for C.H.D. risk factors that included form of treatment, age, sex, and established pre-treatment diastolic pressure (E.D.P.). Thus it would seem that, in severe middle-aged hypertensives, attempts at "normalisation" of high blood-pressure may precipitate as many infarctions as it prevents. Other cardiovascular complications did not exceed the incidence expected during treatment. The findings suggest that the blood-pressure in such patients should seldom be reduced by more than 22% or to diastolic levels less than 104--110 mm Hg.

Adult

Primary osteoathrosis of the hip and Heberden's nodes.

One hundred patients with primary osteoarthrosis of the hip were examined for evidence of generalised arthrosis associated with Heberden's nodes, and in addition their hips were graded by the radiographic pattern of loss of joint space. Twenty-nine patients had bilateral concentric loss of joint space, and 18 in this group had Heberden's nodes. None of the 17 patients with bilateral upper pole changes had Heberden's nodes, and only 7 of the 31 patients with unilateral upper pole changes had Heberden's nodes. None of the 6 patients with medial loss of joint space had Heberden's nodes. This study has shown an association between Heberden's nodes had primary osteoarthrosis of the hip where this is characterised by concentric loss of joint space. The association is most marked where hip changes are bilateral, suggesting that hip involvement in generalised osteoarthrosis is part of a generalised disorder with possible genetic or biochemical abnormalities.

Aged

Compared incidence of first myocardial infarction in hypertensive patients under treatment containing propranolol or excluding beta-receptor blockade.

1. After some exclusions, 169 severe uncomplicated essential hypertensive patients presenting consecutively were divided into two groups according to their treatment. Of these, 121 had been given longterm treatment containing propranolol (PC group) and forty-eight had been treated with hypotensive agents excluding any beta-receptor-blocker group, the non-beta-receptor-blocker (NBB) group. 2. There were no significant differences in myocardial infarction risk factors between the two groups. 3. After a mean follow-up of 5-25 years, nine of the 121 subjects (7-5%) in the PC group had suffered first infarctions and fifteen of the forty-eight subjects (31%) in the NBB group, a significant difference (P less than 0-01). 4. It was concluded that the presence of propranolol had prevented more or caused fewer infarctions, perhaps a combination of both, than had the older hypotensive agents unsupported by beta-receptor blockade.

Adult

Oesophageal motor changes in diabetes mellitus.

Radiography and manometry have been used to study oesophageal motor function in a group of 31 diabetics, 23 of whom had alimentary or genitourinary symptoms attributed to autonomic neuropathy. Peristalsis was of diminished amplitude and oesophageal emptying in the 15 degrees Trendelen-Peristalsis was of diminished amplitude and oesophageal emptying in the 15 degrees Trendelenburg position was delayed. The lower oesophageal sphincter pressure was reduced. The changes seldom caused symptoms and they were not confined to those diabetics with alimentary or genitourinary symptoms attributable to autonomic neuropathy. They suggest that autonomic neuropathy in diabetes is widespread and often subclinical. Degeneration of the ganglion cells of the oesophageal myenteric plexus is associated with hypersensitivity of the oesophageal smooth muscle to cholinergic agents. Bethanecol, a cholinergic drug with muscarinic actions, accelerated oesophageal emptying and increased the lower oesophageal sphincter pressure to normal levels in our diabetics but the hypersensitivity to this drug found in the presence of ganglion cell degeneration was not seen. This implies that in diabetic autonomic neuropathy the predominant lesion is in the preganglionic fibres of the vagus rather than in the myenteric plexus of the oesophageal wall.

Diabetes Mellitus

Vagal impairment of gastric secretion in diabetic autonomic neuropathy.

Gastric acid output in response to insulin-induced hypoglycaemia and pentagastrin was measured in 18 diabetic patients with symptoms of autonomic neuropathy. Two patients had achlorhydria but the rest responded normally to pentagastrin. The acid output evoked by insulin-induced hypoglycaemia was low in 10 of the 16 patients who secreted acid in response to pentagastrin. These changes suggest that vagal impairment is common in diabetics with autonomic symptoms, which might explain the infrequency of duodenal ulcer in diabetics.

Achlorhydria