Attenuation of coronary flow reserve and myocardial function after temporary subtotal coronary artery occlusion and increased myocardial oxygen demand in dogs.

OBJECTIVES: We examined whether subtotal coronary artery occlusion and reperfusion alter coronary flow reserve and regional myocardial function. BACKGROUND: Total coronary artery occlusion followed by reperfusion results in decreased coronary flow reserve and regional myocardial dysfunction. METHODS: Thirteen anesthetized dogs were subjected to subtotal occlusion of the left anterior descending coronary artery for 1 h, followed by reperfusion for 1 h. During subtotal left anterior descending occlusion, heart rate was increased by atrial pacing. After reperfusion, coronary flow reserve, indicated by reactive hyperemia, as well as coronary flow responses to acetylcholine and nitroglycerin, regional myocardial function and myocardial leukocyte accumulation were measured. RESULTS: After reperfusion, coronary flow reserve was decreased in the ischemic left anterior descending but not the nonischemic circumflex coronary artery region. Myocardial function was also depressed in the left anterior descending coronary region and did not improve on reperfusion. Histologic study showed no leukocyte infiltration in the ischemic left anterior descending coronary region. Myeloperoxidase, an index of myocardial leukocyte accumulation, was similar in the left anterior descending and circumflex coronary regions. Sensitivity of epicardial left anterior descending coronary artery rings to the thromboxane A2 analog U46,619 was enhanced, and relaxation of these rings in response to endothelium-dependent relaxants was decreased. CONCLUSIONS: Coronary flow reserve is reduced and regional myocardial function depressed after subtotal coronary artery occlusion and increased heart rate. A decreased synthesis or increased breakdown of endothelium-derived relaxing factor may be related to a decrease in coronary flow reserve. However, the reduction in coronary flow reserve appears to be unrelated to leukocyte accumulation in the reperfused region.

Acute renal failure secondary to fecal impaction.

A 23-year-old man presented with a massive fecal impaction, and was subsequently found to be in renal failure along with the presence of intraperitoneal free air on x-ray. Following disimpaction, the renal failure rapidly resolved and exploratory laporotomy revealed no colonic perforations. Obstructive renal failure resulting from fecal impaction is a rare but reported complication. In this report acute renal failure is attributed to severe fecal impaction.

Treatment of osteoporosis with sodium fluoride and calcium: effects on vertebral fracture incidence and bone histomorphometry.

This article contains a report of the results of a study of 10 postmenopausal women with uncomplicated osteoporosis who were treated with sodium fluoride, calcium supplementation, and vitamin D. Spinal fractures ceased by 18 months, trabecular bone mass increased 26 per cent per year, and patients reported symptomatic improvement.

Microsomal hydroxylation as measured by pentobarbital elimination in patients with idiopathic systemic lupus erythematosus.

A mechanism postulated for drug- or chemical-induced systemic lupus erythematosus (SLE) is that the chemical is covalently bound to nuclear macromolecules increasing the immunogenicity of the macromolecule. This may require metabolic activation by oxidation. There are many similarities between drug-induced and idiopathic SLE. Twelve patients with idiopathic SLE and 12 normal subjects were given 100 mg pentobarbital orally to evaluate their microsomal hydroxylating activity. Plasma pentobarbital concentration was measured by gas-liquid chromatography. Mean plasma pentobarbital half-life was 24 +/- 10 (mean +/- SD) hr in the SLE patients, which is only slightly shorter than the 26 +/- 12 hr in the control subjects. The mean apparent volume of distribution in the patients was 1.28 +/- 0.30 l/kg, which is slightly above the 1.00 +/- 0.37 l/kg in the normal subject (P less than 0.05). Mean metabolic clearance rate in the SLE patients was 0.045 +/- 0.022 l/hr/kg, which is more than the 0.028 +/- 0.008 l/hr/kg in the normal control subjects (P less than 0.02). Since the metabolic clearance rate of a drug is the proper value for evaluating metabolism rate, we conclude that patients with SLE hve an increased elimination rate for drugs or other foreign compounds that are biotransformed by microsomal oxidation and may more rapidly bioactivate chemicals to reactive compounds.

Acetylator phenotype in idiopathic systemic lupus erythematosus.

The acetylator phenotypes of 21 patients from New York City and 29 patients from Israel with idiopathic systemic lupus erythematosus (SLE) were determined with dapsone or isoniazid. Thirty were slwo acetylators, 17 were rapid, and 3 indeterminate. These cases plus published studies of acetylator phenotypes in idiopathic SLE show a worldwide distribution of 150 slow to 77 rapid instead of the expected 122:105 (P less than 0.001). The relationship between acetylator phenotype and possible etiologic agents is discussed.