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Winston M. Hagler - One of the best experts on this subject based on the ideXlab platform.
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influence of duodenal Slaframine infusion on site of nutrient disappearance from the digestive tract of steers fed a high concentrate diet
Journal of Animal Science, 1995Co-Authors: M N Streeter, Mark A. Froetschel, W. J. Croom, Winston M. HaglerAbstract:The effect of duodenal Slaframine (SF) infusion on site and extent of digestion was determined using four steers equipped with ruminal, duodenal, and ileal cannulas in a 4 x 4 Latin square. A 77% dry-rolled corn diet was provided in 12 equal portions daily at a DMI of 2.26% BW. Slaframine in a .9% saline excipient was infused into the duodenum every 12 h with total daily dose of 0, 30, 60, or 90 micrograms /kg of BW. Slaframine infusion had no effect on ruminal pH, ruminal NH3 N, or solids and liquids passage rate. Slaframine increased (linear, P < .10) total tract OM and starch disappearance and digestibility and tended to increase (linear, P = .14) total tract N digestibility. Ruminal starch disappearance tended to be decreased (quadratic, P = .16) by SF. Small intestinal OM digestibility was increased (linear, P < .10) but starch digestibility in the small intestine was not affected by SF. Increased total tract starch digestibility was caused by increased (quadratic, P < .10) starch fermentation in the large intestine. Ruminal feed N digestibility decreased at the intermediate doses of SF (quadratic, P < .10). Total N digestibility in the small intestine tended to be increased (cubic, P = .13) with 30 and 90 micrograms of SF/kg of BW. Decreased ruminal feed N digestion was compensated for by increased (quadratic, P < .10) small intestinal feed N disappearance for steers treated with intermediate doses of SF. The potential of SF to increase starch digestion in the rumen and small intestine seems to be limited.
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The involvement of Slaframine and swainsonine in slobbers syndrome: a review.
Journal of Animal Science, 1995Co-Authors: Warren J. Croom, Mark A. Froetschel, Winston M. Hagler, A. D. JohnsonAbstract:The history of «slobbers syndrome,» a mycotoxicosis associated with Rhizoctonia leguminicola infestation of pastures and stored forages, is discussed. The chemistry and physiological effects of the two known biologically active alkaloids of R. leguminicola, Slaframine and swainsonine, are described. Slaframine administration is generally associated with increased exocrine function, especially salivation. Ingestion of swainsonine may be linked to serious and potentially lethal central nervous system defects similar to that described for locoism. However, the singular effects of these alkaloids do not completely account for the total clinical picture noted in the field during the occurrence of slobbers syndrome. It is possible that this phenomenon is the result of an interaction between both known and unidentified biologically active metabolites of R. leguminicola
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effects of abomasal Slaframine infusion on ruminal digesta passage and digestion in steers
Canadian Journal of Animal Science, 1995Co-Authors: Mark A. Froetschel, Henry E. Amos, W. J. Croom, M N Streeter, Winston M. HaglerAbstract:Slaframine was infused intra-abomasally once daily 3 h after feeding to four ruminally and abomasally cannulated Jersey steers (586 ± 88.6 kg) at 0 (saline control), 10, 20, or 30 μg kg−1 BW in a 4 × 4 Latin square design experiment. Periods were 14 d in length. On a DM basis, diets were a 38:62, sorghum silage: concentrate offered at 125% of the net energy required for maintenance. Ruminal, abomasal, and fecal samples were collected at 2-h intervals on days 10–12, and ruminal contents were completely evacuated and sampled at 3, 6, 12, and 24 h after feeding on days 13 and 14. Ruminal volume and pH increased (linear; P < 0.05) from 1.6 to 8.9% and from 0.10 to 0.22 units, respectively, with SF. Total ruminal VFA and ammonia concentrations decreased (linear; P < 0.05) with SF from 4.1 to 9.4% and from 5.3 to 10.2%, respectively. Apparent ruminal DM and starch digestion increased at the lowest dosage and decreased at higher dosages of SF (quadratic; P < 0.05). Ruminal NDF digestion decreased with SF (linear...
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the effect of Slaframine on salivary output and subacute and acute acidosis in growing beef steers
Journal of Animal Science, 1995Co-Authors: B Hibbard, W. J. Croom, J P Peters, S T Chester, J A Robinson, S F Kotarski, Winston M. HaglerAbstract:Experiments were conducted to determine 1) the effect of injecting Slaframine (SF) on salivary output in growing beef steers and 2) whether increased salivary output after SF injection would inhibit the decrease in ruminal pH that occurs after experimentally induced subacute and acute ruminal acidosis. In Exp. 1 and 2, we measured ruminal pH and salivary output in ruminally and esophageally cannulated beef steers fed an 88% concentrate diet. Injections of 66 or 100 micrograms of SF/kg BW increased salivary flow approximately 50% compared with controls. Those doses were tested in subacute and acute acidosis models using ruminally cannulated beef steers in Exp. 3 and 4, respectively. In these experiments, salivation was assessed indirectly using a visual scoring system. In the subacute acidosis model, SF reduced (P .10) in ruminal pH at 12 h after injection between control and SF-treated steers. Mean ruminal lactate concentrations for all treatment groups were between 87 and 112 mM. Although treatment with 66 micrograms of SF/kg BW reduced (P < .10) ruminal lactate concentrations, all ruminal lactate concentrations were indicative of acute acidosis. These results indicate that SF will reduce the decrease in ruminal pH associated with subacute acidosis in growing beef steers, but SF does not attenuate acute ruminal acidosis.
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Slaframine and swainsonine production by rhizoctonia leguminicola isolated from six outbreaks of slobbers in cattle and horses
1994Co-Authors: Linda R Daniel, Winston M. Hagler, Warren J. CroomAbstract:O’Dell et al. (1959) in Missouri reported their investigations into “slobbers,” a syndrome characterized by slobbering and other toxic symptoms in ruminants and horses consuming red clover (Trifolium pratense L.) and, rarely, other legume forages, particularly alfalfa (Medicago sativa L.). Death of an animal was unusual, but was reported in a few cases. Slobbers (salivary syndrome) in cattle and horses was shown during the late 1960’s to be due to the consumption of legume forages infected with a non-spore producing fungus Rhizoctonia leguminicola (Gough and Elliot, 1956). Smalley et al. (1962) first isolated the causative fungus and Gardiner et al. (1968) published the strcuture of an indolizidine alkaloid (1-acetoxy-6aminooctahydro-indolizine) given the trivial name, Slaframine, which reproduced the syndrome in livestock and laboratory animals (Aust et al., 1968) when administered in purified form. Hagler and Behlow (1981) were the first to directly identify the presence of Slaframine in samples of red clover hay that caused salivation in horses. Broquist et al. (1985) identified swainsonine (1,2,8-trihydroxyoctahydroindolizine), a structurally related alkaloid, in the same hay sample.
William H Pearson - One of the best experts on this subject based on the ideXlab platform.
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synthesis of Slaframine and related indolizidines
Journal of Organic Chemistry, 1992Co-Authors: William H Pearson, Stephen C Bergmeier, John P WilliamsAbstract:An enantioselective synthesis of the indolizidine alkaloid (-)-Slaframine 1 is reported. Reductive double cylization of the azido epoxy tosylate 48 afforded the indolizidine 52, which was converted to (-)-Slaframine in two steps. The cyclization substrate 48 was prepared in optically pure form from L-glutamic acid. A similar sequence starting with the epoxide 49 allowed the synthesis of (-)-1,8a-diepiSlaframine 56. Other routes routes to Slaframine were investigated, ofen using an intramolecular cycloaddition of an azide with an alkene as a key step
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a synthesis of Slaframine and 1 8a diepiSlaframine
Journal of Organic Chemistry, 1991Co-Authors: William H Pearson, Stephen C BergmeierAbstract:The first synthesis of natural (−)-Slaframine 1 was accomplished in 6% overall yield in 12 steps from N-benzyl-L-glutamic acid
Stephen C Bergmeier - One of the best experts on this subject based on the ideXlab platform.
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synthesis of Slaframine and related indolizidines
Journal of Organic Chemistry, 1992Co-Authors: William H Pearson, Stephen C Bergmeier, John P WilliamsAbstract:An enantioselective synthesis of the indolizidine alkaloid (-)-Slaframine 1 is reported. Reductive double cylization of the azido epoxy tosylate 48 afforded the indolizidine 52, which was converted to (-)-Slaframine in two steps. The cyclization substrate 48 was prepared in optically pure form from L-glutamic acid. A similar sequence starting with the epoxide 49 allowed the synthesis of (-)-1,8a-diepiSlaframine 56. Other routes routes to Slaframine were investigated, ofen using an intramolecular cycloaddition of an azide with an alkene as a key step
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a synthesis of Slaframine and 1 8a diepiSlaframine
Journal of Organic Chemistry, 1991Co-Authors: William H Pearson, Stephen C BergmeierAbstract:The first synthesis of natural (−)-Slaframine 1 was accomplished in 6% overall yield in 12 steps from N-benzyl-L-glutamic acid
Warren J. Croom - One of the best experts on this subject based on the ideXlab platform.
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The involvement of Slaframine and swainsonine in slobbers syndrome: a review.
Journal of Animal Science, 1995Co-Authors: Warren J. Croom, Mark A. Froetschel, Winston M. Hagler, A. D. JohnsonAbstract:The history of «slobbers syndrome,» a mycotoxicosis associated with Rhizoctonia leguminicola infestation of pastures and stored forages, is discussed. The chemistry and physiological effects of the two known biologically active alkaloids of R. leguminicola, Slaframine and swainsonine, are described. Slaframine administration is generally associated with increased exocrine function, especially salivation. Ingestion of swainsonine may be linked to serious and potentially lethal central nervous system defects similar to that described for locoism. However, the singular effects of these alkaloids do not completely account for the total clinical picture noted in the field during the occurrence of slobbers syndrome. It is possible that this phenomenon is the result of an interaction between both known and unidentified biologically active metabolites of R. leguminicola
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Slaframine and swainsonine production by rhizoctonia leguminicola isolated from six outbreaks of slobbers in cattle and horses
1994Co-Authors: Linda R Daniel, Winston M. Hagler, Warren J. CroomAbstract:O’Dell et al. (1959) in Missouri reported their investigations into “slobbers,” a syndrome characterized by slobbering and other toxic symptoms in ruminants and horses consuming red clover (Trifolium pratense L.) and, rarely, other legume forages, particularly alfalfa (Medicago sativa L.). Death of an animal was unusual, but was reported in a few cases. Slobbers (salivary syndrome) in cattle and horses was shown during the late 1960’s to be due to the consumption of legume forages infected with a non-spore producing fungus Rhizoctonia leguminicola (Gough and Elliot, 1956). Smalley et al. (1962) first isolated the causative fungus and Gardiner et al. (1968) published the strcuture of an indolizidine alkaloid (1-acetoxy-6aminooctahydro-indolizine) given the trivial name, Slaframine, which reproduced the syndrome in livestock and laboratory animals (Aust et al., 1968) when administered in purified form. Hagler and Behlow (1981) were the first to directly identify the presence of Slaframine in samples of red clover hay that caused salivation in horses. Broquist et al. (1985) identified swainsonine (1,2,8-trihydroxyoctahydroindolizine), a structurally related alkaloid, in the same hay sample.
Timothy Gallagher - One of the best experts on this subject based on the ideXlab platform.
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heterocyclic ketones as pre formed building blocks synthesis of Slaframine
Tetrahedron Letters, 1995Co-Authors: Peter Szeto, David Lathbury, Timothy GallagherAbstract:Summary A synthesis of lactam 2 , which constitutes a formal total synthesis of (−)-Slaframine 1 , is described with key steps being (a) intramolecular aldol reaction of ketoaldehyde 4 to establish the indolizidine framework and (b) diastereoselective reduction of enone 5 using the Corey oxazaborolidine 7 .