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Nasogastric infusion of a human enteral feeding preparation was effective in reversing hyperlipemia in an anorectic miniature horse with an esophageal laceration. The nutrient preparation was delivered every 4 hours by gravity flow through a 12 F enteral feeding tube. Within 48 hours of initiating enteral nutrition, the hyperlipemia had resolved. Signs of intolerance to the preparation were not observed, and further weight loss was prevented. The use of a human enteral formula was a convenient and successful alternative for the treatment of hyperlipemia in the horse.

The interaction of histamine (Hist) and acetylcholine (ACh) on human isolated bronchial smooth muscle (HIBSM) contraction, and the influence of the epithelium, was assessed using HIBSM obtained from 15 patients undergoing thoracotomy. Cumulative concentration effect curves for ACh and Hist, together with combinations of equipotent concentrations of both agonists, were generated using both epithelium-intact and epithelium-denuded HIBSM. In epithelium-denuded HIBSM both ACh (p less than 0.05) and Hist (p less than 0.005) produced a significantly enhanced maximal response and a 2.1 fold increase in the potency of ACh (p less than 0.02, n = 13). When ACh and Hist were added simultaneously, in equipotent concentrations, to epithelium-intact HIBSM, a significantly less (p less than 0.0005, n = 13) than additive response occurred with only 60% of the predicted maximum response being observed. However, following epithelium removal, an additive interaction between the two agonists (n = 8) occurred. Using HIBSM from five of the original 15 patients, similar experiments were performed to determine the influence of the muscarinic receptor antagonist atropine (0.1 microM) and the H1 receptor antagonist mepyramine (10 microM). Both resulted in a significantly less than additive interaction (40-50% of predicted tensions). Similar experiments were also performed in the presence of the cyclo-oxygenase inhibitor indomethacin (5 microM) and these failed to reverse the inhibition observed in HIBSM contraction (n = 5). The inhibitory interaction between ACh and Hist appears to be epithelium dependent and is not mediated via the release of prostanoids. Thus, there appears to be a complex interaction between contractile agonists and the epithelium, which is not just a simple summation of the activation of individual receptors on HIBSM.

After a three day acclimatization period, six healthy, young (aged 4 to 20 days) orphan foals of mixed breeding were fed 100 per cent of their caloric needs (estimated at 523 kjoules/kg bodyweight [bwt] or 125 kcal/kg bwt/day) as a low residue isotonic feeding solution (LRF) for seven days. The solution provided 4.18 kjoules (1 kcal/ml) and was fortified with minerals and protein to meet estimated foal requirements. The solution was fed through an indwelling 12 French feeding tube. Five of the six foals completed the study; the loss of the sixth foal apparently was unrelated to the feeding protocol. The foals tolerated LRF well. Signs of intolerance were noted in two foals and were limited to flatulence, mild bloat and very mild abdominal pain associated with a decreased interval between two feedings during the first 48 h on 100 per cent LRF. Complete recovery without therapy occurred within 6 h and feedings were resumed. Growth in height and weight were comparable to published data for healthy foals raised with their dams. Feeding tubes were easily maintained with no apparent dysphagia, regurgitation or discomfort to foals. This low residue, calorically dense, isotonic feeding solution may be useful for enteral feeding of selected foals aged at least seven days.

The potential role of dietary copper in the development of cartilage defects in foals was investigated. Twenty-one mares were fed rations containing 13 ppm copper (CuC, control) or 32 ppm copper (CuS, supplemented) during the last three to six months of gestation and first three months of lactation. Their foals were fed pelleted concentrate containing 15 or 55 ppm Cu and were destroyed at 90 (5 CuC and 5 CuS foals) or 180 (6 CuC and 5 CuS foals) days. Focal cartilage lesions were found at multiple sites on necropsy. In foals killed at 90 days, there were over twice (9 versus 4) as many lesions of osteochondrosis and more than four times (9 versus 2) as many articular lesions of osteophyte formation or thinning in CuC foals compared with CuS foals. These differences were due predominantly to a higher number of lesions in one CuC foal. Two 90-day CuC foals had osteochondrosis of articular-epiphyseal (A-E) complex, one with thickenings and separation from subchondral bone and one with subchondral fibrosis. One 90-day CuS foal had a cartilage thickening of the A-E complex in the tibiotarsal joint with separation from subchondral bone. In foals killed at 180 days, there were seven times more articular lesions (21 versus 3) of osteophyte formation or thinning, nearly twice as many lesions of osteochondrosis (13 versus 8) [corrected] in the physis and over five times as many involving the A-E complex (11 versus 2) in six CuC foals compared with five CuS foals.(ABSTRACT TRUNCATED AT 250 WORDS)

Plutonium-237 decays mainly by electron capture with a half-life of 45 d. Alpha particles are emitted in only 5 x 10(-3)% of its disintegrations. This nuclide can now be produced with relatively small amounts of alpha-emitting contaminants so that, in principle, 237Pu can be used for studies of Pu biokinetics in man. However, because of its high specific activity, there was some doubt that its metabolism would be the same as that of the alpha- and beta-emitting isotopes of Pu normally encountered in the nuclear industry. In this study, the biokinetics of nearly "pure," high specific activity 237Pu are compared with those of lower specific activity, "impure" 237Pu containing significant amounts of alpha-emitting Pu, following administration to rats by intravenous injection as the citrate. Both the distribution and excretion of the "pure" and "impure" 237Pu used in the two studies were similar and also in good agreement with the results of previously reported studies using 239Pu and 241Pu citrate, thus validating the use of 237Pu for studies of Pu metabolism in man. Data on the biokinetics of 237Pu nitrate are also included.

Fifteen Shetland ponies were used in a 7-wk trial to study the effect of supplemental Se on humoral antibody production. Four 3-yr-old, five 2-yr-old and six yearling ponies were depleted of Se before being assigned randomly to either a low Se (.02 ppm) or higher Se (.22 ppm) diet. Each pony was challenged antigenically with 2 ml of sheep packed red blood cells upon receiving its respective diet and again 2 wk post-treatment. Blood samples were drawn weekly and assayed for glutathione peroxidase activity, Se and immunoglobulin concentration and antibody titers. Compared with those ponies receiving the low Se concentrate, ponies receiving the Se-supplemented diet had higher (P less than .01) glutathione peroxidase activities and blood Se concentrations during the later weeks of the experiment. An enhanced primary response was observed in Se-supplemented ponies as evidenced by increased hemagglutination titers. Higher IgG concentrations (P less than .01) also were observed in the Se-supplemented group. Dietary Se concentration of .02 ppm was inadequate for optimum immune function in the equine.

The respiratory epithelium produces a variety of inflammatory mediators which may be influencing the bronchial hyperreactivity observed in patients with asthma. Animal studies have demonstrated that removal of the epithelium from tracheal and bronchial smooth muscle causes enhanced responses to cholinergic agonists and histamine (Hist). In this study the effect of epithelium removal on human bronchial smooth muscle response to acetylcholine (ACh) and Hist was assessed. Bronchial smooth muscle was obtained fresh from the operating theatre from 12 patients undergoing thoracotomy. Cumulative concentration effect curves (CCEC) for Hist and ACh were generated for epithelium intact and epithelium denuded muscle strips. All CCEC's were performed in duplicate and all denuded strips were obtained from the same airway immediately adjacent to the intact strip. The mean (+/- SEM) maximum response for Hist for the intact strip was 8.6 +/- 1.1 (grams/gram wet weight) and 12.0 +/- 1.4 (grams/gram wet weight) for the denuded strip (p less than 0.05). For ACh the values were 9.3 +/- 1.3 (g/g wet weight and 14.3 +/- 1.8 (g/g wet weight), respectively (p less than 0.05). The pD2 (-log EC50) for ACh was increased two-fold following epithelium removal (p less than 0.05). For Hist there was a similar increase in pD2 but this did not reach statistical significance. Thus removal of the epithelium from human isolated bronchial smooth muscle appears to modulate responsiveness to ACh and Hist. This enhanced responsiveness consequent to epithelium loss may prove important with respect to the development of worsening asthma.

Exposure to (-)-isoprenaline (25 microM, 1 h) caused a stereoselective, time and concentration-related decrease in smooth muscle beta 2-adrenoceptor function in guinea-pig trachea. Furthermore, tracheal relaxant responsiveness to the beta-adrenoceptor agonists (+/-)-fenoterol and (-)-noradrenaline was reduced, while that to theophylline and nitroprusside was unaffected. Responsiveness to forskolin was marginally but significantly reduced. Indomethacin, a cyclooxygenase inhibitor and mepacrine, an inhibitor of phospholipid turnover, had no significant effect on the extent of isoprenaline-induced desensitization. Conversely, cortisol (25 microM) significantly reduced desensitization and enhanced the rate of spontaneous recovery of responsiveness to isoprenaline. Desensitization was not accompanied by a reduction in the density of beta-adrenoceptors in the trachea, as assessed by binding and light microscopic autoradiography using [125I]iodocyanopindolol [( 125I]CYP). Thus, desensitization was probably caused primarily by beta-adrenoceptor/adenyl cyclase uncoupling. This model may be useful in investigations of the effect of glucocorticoids on the beta-adrenoceptor dysfunction recognized in severe asthma.

Fourteen Quarter Horse foals were used to evaluate the effects of artificial rearing on growth. Seven foals were removed from their dams at 3 d of age and fed a reconstituted 26% crude protein (CP) milk replacer free choice for 1 mo, at which time ad libitum solid feeding began. Controls were weaned from their dams at 2 mo of age and fed a 21% CP concentrate ad libitum until the end of the trial. Variables measured during the 26-wk trial were live body weight, height at the withers and length of body from point of shoulder to point of hip. No significant differences were found between the two groups, except during wk 8 where 2-mo weaned foals were slightly heavier (P less than .10). Average daily gains for artificially reared and 2-mo weaned foals were .95 and .98 kg, respectively.