Regional infusion of urokinase into occluded lower-extremity bypass grafts: long-term clinical results

The initial outcome, long-term patency rate, and rate of limb salvage were studied in patients after regional urokinase infusion for treatment of thrombosed lower-extremity grafts. Seventy-one infusions were performed in 53 patients. Complete clot lysis occurred in 75% of grafts, with establishment of antegrade blood flow in 66%. Variables that favorably influenced clot lysis and the reestablishment of antegrade blood flow through the graft were a short duration of occlusion and a suprainguinal graft position. The median duration of patency after infusion and adjunctive therapy was 162 days, with 75% limb salvage at 301 days. No statistically significant variables that influenced the length of patency were identified. These long-term patency results are inferior to the reported results in suprainguinal grafts after reoperation. They appear similar to reported results for occluded infrainguinal grafts treated with thrombectomy and patch grafting.     

Role of Gallbladder Mucus Hypersecretion in the Evolution of Cholesterol Gallstones: STUDIES IN THE PRAIRIE DOG

Because mucin glycoproteins may be important in the pathophysiology of gallstones, we studied the relationship among biliary lipids, gallbladder mucin secretion, and gallstone formation in cholesterol-fed prairie dogs. Organ culture studies of gallbladder explants revealed that the incorporation of [³H]glucosamine into tissue and secretory gallbladder glycoproteins was significantly increased at 3, 5, 8, and 14 d of feeding. Peak secretion of labeled mucin occurred at 5 d, when total tissue and secreted glycoprotein production was fivefold greater than control. Gel filtration of the secreted glycoprotein on Sepharose 4B indicated that the majority of radioactivity was present in a macromolecule of > 1 million molecular weight. The increased secretion of gallbladder mucin was organ specific, in that [³H]glucosamine incorporation into glycoproteins of stomach and colon was unaffected by cholesterol feeding. Similarly, the incorporation of [³H]mannose into gallbladder membrane glycoproteins was not altered by cholesterol feeding. The rate of glycoprotein synthesis and secretion returned to normal upon withdrawal of the cholesterol diet, and ligation of the cystic duct before cholesterol feeding prevented gallbladder mucin hypersecretion. Both results indicate that the stimulus to mucin secretion was a constituent of bile. Gallbladder bile after 5 d contained cholesterol in micelles, liquid crystals, and crystals, whereas hepatic bile remained a single micellar phase throughout cholesterol feeding. For this reason the cholesterol-saturation indices of gallbladder bile were compared in both homogenized and centrifuged samples. The micellar phase of gallbladder bile was appreciably less saturated than homogenized bile at 5 and 8 d, which reflects the continuous nucleation of cholesterol in the gallbladder. Purified human gallbladder mucin gels were shown to induce nucleation of lecithin-cholesterol liquid crystals from supersaturated hepatic bile. These in turn gave rise to cholesterol monohydrate crystals within 18 h. Control supersaturated hepatic bile could not be nucleated by the addition of other proteins, and was stable for days upon standing. These results suggest that the increase in cholesterol content of bile in cholesterolfed prairie dogs stimulates gallbladder mucus hypersecretion, and that gallbladder mucus gel is a nucleating agent for biliary cholesterol.     

Circulatory effects of ventilator rate and end-expiratory pressure in unparalysed preterm infants

Impairment of cerebrovascular autoregulation may be important in the pathogenesis of ischaemic brain injury in preterm infants. A previous study in ventilated preterm infants paralysed with pancuronium showed that changes in cerebral blood flow velocity (CBFV) were related to concomitant changes in arterial blood pressure. In a similar study in unparalysed infants, changes in CBFV in response to changes in ventilator rate or end-expiratory pressure were independent of associated changes in the arterial blood pressure. These results emphasize the importance of avoiding large swings in blood pressure in paralysed infants. Whether alternative paralysing agents have similar effects warrants further study.     

Sugar malabsorption in healthy neonates estimated by breath hydrogen

Carbohydrate malabsorption in 110 healthy, term neonates was studied by estimating expired hydrogen (H2) before and after a feed on day 6 or 7. Carbohydrate malabsorption was assumed to be present if the infant excreted > 20 parts per million (ppm) H2. The frequency of carbohydrate malabsorption in 49 breast-fed infants was 25% (n = 12), in 35 infants fed a 7.5% lactose formula it was 31% (n = 11), in 26 infants fed a formula containing 1% lactose and 7.3% maltodextrin it was 15% (n = 4). These differences in frequency were not significant. Peak H2 concentration of the malabsorbers in each group, indicating the degree of carbohydrate malabsorption, was 64, 52, and 32 ppm respectively. The degree of carbohydrate malabsorption did not differ significantly between the breast-fed and the high lactose formula groups, but both groups differed from the low lactose group. H2 excretion was studied for 5 months in an exclusively breast-fed infant. In the first 2 months high concentrations were found and the infant produced 3-5 stools a day. In the next 3 months however, most H2 estimations were normal and only 1-2 stools a week were passed. With the introduction of solids, daily bowel movements promptly reoccurred. Frequency of carbohydrate malabsorption in newborn infants is fairly high and is primarily related to the lactose intake. The frequency and degree of carbohydrate malabsorption were comparable in breast-fed infants and in infants fed on a high lactose formula; this differs from results previously reported.