Nancy Shappell - Academia.edu (original) (raw)
Papers by Nancy Shappell
Journal of Animal Science, Jun 1, 2002
J Agr Food Chem, 2007
A novel preharvest technology that reduces certain pathogenic bacteria in the gastrointestinal tr... more A novel preharvest technology that reduces certain pathogenic bacteria in the gastrointestinal tracts of food animals involves feeding an experimental sodium chlorate-containing product (ECP) to animals 24-72 h prior to slaughter. To determine the metabolism and disposition of the active ingredient in ECP, four male Sprague-Dawley (approximately 350 g) rats received a single oral dose of sodium [36Cl]chlorate (3.0 mg/kg body weight). Urine, feces, and respired air were collected for 72 h. Radiochlorine absorption was 88-95% of the administered dose, and the major excretory route was the urine. Parent chlorate was the major species of radiochlorine present in urine at 6 h (approximately 98%) but declined sharply by 48 h (approximately 10%); chloride was the only other species of radiochlorine detected. Except for carcass remains (4.6% of dose), skin (3.2%), and gastrointestinal tract (1.3%), remaining tissues contained relatively low quantities of radioactivity, and >98% of radiochlorine remaining in the liver, kidney, and skeletal muscle was chloride. Chlorite instability was demonstrated in rat urine and bovine urine. The previously reported presence of chlorite in excreta of chlorate-dosed rats was shown to be an artifact of the analytical methods employed. Results from this study indicate that chlorate is rapidly absorbed and reduced to chloride, but not chlorite, in rats.
Environmental Science Technology, 2010
In Vitro Cell Dev Biol Animal, 2003
Journal of Animal Science
Journal of Nutrition
Ten pregnant heifers and 10 pregnant cows (three or more pregnancies) were assigned to groups of ... more Ten pregnant heifers and 10 pregnant cows (three or more pregnancies) were assigned to groups of five and fed either the recommended (low) amount of calcium or excess (high) calcium in their diet for 4 wk before parturition to determine the influence of prepartum calcium intake and age on hormonal control of peripartum calcium homeostasis. After parturition all groups received a diet with calcium adequate for lactation. Jugular blood samples from 21, 14, 7, 6, 5, 4, 3, 2, and 1 d prepartum through 0, 1, 2, 3, 5, 7, 14 and 21 d postpartum were assayed for concentration of parathyroid hormone, calcitonin, calcium, magnesium and phosphorus. Heifers and cows receiving high calcium diets had higher calcium and lower parathyroid hormone in blood serum before parturition than animals receiving the low calcium diets. Cows, but not heifers, fed high calcium diets exhibited severe hypocalcemia at parturition, remained hypocalcemic for 3 d and had low serum calcitonin. Regardless of dietary group, concentrations of parathyroid hormone and magnesium in serum increased after the first week of lactation. Feed intake during lactation, corrected for metabolic body weight, was similar for both dietary treatments and ages. Milk production per kilogram metabolic body weight was highest during the first week of lactation for cows fed low calcium diets before parturition. There was no correlation between hypocalcemia and loss of calcium in colostrum or milk. Feeding low dietary calcium to cows in the prepartum period was effective in the prevention of severe hypocalcemia at parturition. In contrast, dietary treatment of heifers had no effect on serum calcium concentration at parturition.(ABSTRACT TRUNCATED AT 250 WORDS)
Journal of Animal Science
Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), persistent pol... more Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), persistent pollutants that accumulate in the food chain, pose a risk to humans through consumption of tainted livestock. Clenbuterol, a leanness-enhancing agent, was tested for usefulness in PCDD/F body store reduction through body fat reduction (the predominant site of accumulation). To mimic the situation of contaminated animals, rats were given feed with or without a mixture of PCDD/F (0.6 to 2.7 ng/congener per day) for 10 d, followed by 16 d of feed with or without dietary clenbuterol (2 mg/kg feed). Clenbuterol reduced body fat by 28% (P < 0.05), increased muscle mass by 25% (P < 0.02), and decreased liver mass by 7% (P < 0.02). Although the concentrations of most PCDD/F per gram of fat were slightly increased after clenbuterol treatment, the total amount of PCDD/F that remained in fat was reduced by approximately 30%. Muscle PCDD/F concentrations and total burden were decreased by clenbuterol. In contrast, clenbuterol tended to increase concentration, but not total burden of PCDD/F in livers. One congener known to be rapidly metabolized and excreted, 2,3,7,8-TCDF, was the exception to this increase, decreasing 40% with clenbuterol treatment. This was also the congener that showed the greatest reduction in both fat and muscle. Examination of the ratio of PCDD/F in liver and fat revealed that clenbuterol increased the liver's share of the body burden of PCDD/F, from 38 to 75%. In a remediation/disposal context, these findings would be beneficial if clenbuterol lowered the meat and carcass burden of PCDD/F to safe levels, requiring only livers to be disposed of as hazardous waste.
Journal of Biological Chemistry
In MALME-3M human melanoma cells the polyamine analog N1,N12-bis(ethyl)spermine (BESPM) suppresse... more In MALME-3M human melanoma cells the polyamine analog N1,N12-bis(ethyl)spermine (BESPM) suppresses the key polyamine biosynthetic enzymes, ornithine and S-adenosylmethionine decarboxylase, and increases the polyamine catabolizing enzyme, spermidine/spermine N1-acetyl-transferase (SSAT) by more than 200-fold. In the present study increases in SSAT activity in MALME-3M cells treated with 10 microM BESPM were found to be accompanied by a substantial (up to 45-fold) accumulation of SSAT mRNA. By Northern blot analysis three RNA transcripts were found to hybridize with the coding region of human SSAT cDNA: a minor high molecular weight (approximately 3.5 kilobases) species designated form A and two lower molecular weight species designated forms B and C (approximately 1.5 and approximately 1.3 kilobases, respectively). Form A increased uniformly during BESPM treatment and was most obvious in nuclear RNA preparations. On the basis of size similarity to the transcribing region of the gene and hybridization with the coding region of SSAT cDNA and its prevalence in nuclear mRNA preparations, form A is thought to represent precursor SSAT RNA. Form C is present in control cells and increases steadily during treatment, whereas form B increases transiently during early treatment (1-3 h). By RNase H digestion assay, form B was found to have a 200-base pair longer poly(A) tract and as such may represent a precursor to form C. Accumulation of SSAT mRNA was found to be a result of increased gene transcription and stabilization of SSAT mRNA. Nuclear run-on studies indicated a 2-4-fold increase in the transcription rate of the SSAT gene. As indicated by actinomycin D studies, the SSAT mRNA half-life increased with BESPM treatment from 17 to 64 h. The natural polyamine, spermine, also increased SSAT mRNA (5.5-fold at 24 h) and behaved similarly to BESPM in inducing the appearance of the same three transcript forms. The polyamine was much less effective than the analog at increasing enzyme activity. Lowering intracellular polyamine pools with inhibitors of biosynthesis decreased basal SSAT mRNA levels by at least 70% indicating, that the gene can be down-regulated as well as up-regulated by polyamines. These findings indicate that SSAT represents a unique example of gene expression being positively influenced at the RNA level by polyamines and their analogs.
Dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the envi... more Dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the environmental fate and transport of steroidal estrogens. This study quantified the association of the natural occurring 17beta-estradiol (E2), with the DF and CF isolated from liquid swine manure (LSM), Soil, and LSM and Soil mixtures (Soil+LSM). The appropriate CF and DF size fractions of the Soil, Soil+LSM, and LSM materials were obtained by first filtering through a 0.45 µm filter, which provided the combined DF and CF (DF/CF). The DF/CF from the three media were spiked with radiolabelled (14C) E2, and then ultrafiltrated to isolate the CF (<0.45 mm and > 1 kDa) from the DF (<1 kDa). The average recoveries of the 14C E2 associated with the DF were 67%-72%, 67%-79%, and 76%-78% for the Soil, Soil+LSM and LSM, respectively. For the CF that was retained on the 1 kDa filter, organic carbon (OC) and 14C-E2 were dislodged with subsequent water rinses for all three media. The Soil media...
The effects of ractopamine (RAC) and ractopamine stereoisomers (RR, RS, SR, and SS) on cyclic AMP... more The effects of ractopamine (RAC) and ractopamine stereoisomers (RR, RS, SR, and SS) on cyclic AMP (cAMP) production, total protein, and DNA concentrations in mouse skeletal muscle cells (C2C12) were evaluated. The RAC (10 M) caused an ∼30% in- crease in cell number, protein, and DNA concentrations in myoblasts after 48 h; no differences were found in myotubes. The RAC-stimulated
Purifiedergopeptinealkaloidsareoften used in studies related to tall fescue toxicosis without reg... more Purifiedergopeptinealkaloidsareoften used in studies related to tall fescue toxicosis without regard to epimerization that occurs when ergopeptines are solvated. The objectives of this study were to mea- sure the rates of α-ergocryptine epimerization to α- ergocryptinine at room temperature and at −40°C, and to measure the rate of ergovaline epimerization to ergo- valinine at 37°C. α-Ergocryptine tartrate was stable (<
Ten pregnant heifersand 10 pregnant cows (three or more pregnancies)were assignedto groups of fiv... more Ten pregnant heifersand 10 pregnant cows (three or more pregnancies)were assignedto groups of five and fed either the recommended,(low) amount,of calcium or excess (high) calcium in their diet for 4 wk before parturitionto determine the influenceof prepartum calcium intake and age on hormonal control of peripartumcalcium homeostasis. After parturitionall groupsreceiveda diet with calciumadequatefor lactation.Jugular bloodsamplesfrom 21,14,7, 6, 5,4, 3,
The Science of the total environment, 2014
The dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the ... more The dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the environmental fate and transport of steroidal estrogens. The first objective of this study was to quantify the association of 17β-estradiol (E2) with the DF and CF isolated from (i) liquid swine manure (LSM), (ii) a soil:water mixture (soil), and (iii) a LSM:soil:water mixture (Soil+LSM). The appropriate CF and DF size fractions of the Soil, Soil+LSM, and LSM media were obtained by first filtering through a 0.45 μm filter, which provided the combined DF and CF (DF/CF). The DF/CF from the three media was spiked with carbon-14 ([(14)C]) radiolabeled E2 ([(14)C]-E2), and then ultrafiltered to isolate the CF (<0.45 μm and >1 kDa) from the DF (<1 kDa). The average recoveries of the [(14)C] associated with the DF were 67%-72%, 67%-79%, and 76%-78% for the Soil, Soil+LSM and LSM, respectively. For the CF that was retained on the 1 kDa filter, organic carbon and [(14)C]-E2 were dislodge...
Environmental science & technology, Jan 15, 2008
Endocrine disrupting chemicals (EDCs) impair living organisms by interfering with hormonal proces... more Endocrine disrupting chemicals (EDCs) impair living organisms by interfering with hormonal processes controlling cellular development Reduction of EDCs in water by an environmentally benign method is an important green chemistry goal. One EDC, 17alpha-ethinylestradiol (EE2), the active ingredient in the birth control pill, is excreted by humans to produce a major source of artificial environmental estrogenicity, which is incompletely removed by currenttechnologies used by municipal wastewater treatment plants (MWTPs). Natural estrogens found in animal waste from concentrated animal feeding operations (CAFOs) can also increase estrogenic activity of surface waters. An iron-tetraamidomacrocyclic ligand (Fe-TAML) activator in trace concentrations activates hydrogen peroxide and was shown to rapidly degrade these natural and synthetic reproductive hormones found in agricultural and municipal effluent streams. On the basis of liquid chromatography tandem mass spectrometry, apparent half-...
Journal of animal science, 2002
Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), persistent pol... more Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), persistent pollutants that accumulate in the food chain, pose a risk to humans through consumption of tainted livestock. Clenbuterol, a leanness-enhancing agent, was tested for usefulness in PCDD/F body store reduction through body fat reduction (the predominant site of accumulation). To mimic the situation of contaminated animals, rats were given feed with or without a mixture of PCDD/F (0.6 to 2.7 ng/congener per day) for 10 d, followed by 16 d of feed with or without dietary clenbuterol (2 mg/kg feed). Clenbuterol reduced body fat by 28% (P < 0.05), increased muscle mass by 25% (P < 0.02), and decreased liver mass by 7% (P < 0.02). Although the concentrations of most PCDD/F per gram of fat were slightly increased after clenbuterol treatment, the total amount of PCDD/F that remained in fat was reduced by approximately 30%. Muscle PCDD/F concentrations and total burden were decreased by clen...
Journal of animal science, 2002
Purified ergopeptine alkaloids are often used in studies related to tall fescue toxicosis without... more Purified ergopeptine alkaloids are often used in studies related to tall fescue toxicosis without regard to epimerization that occurs when ergopeptines are solvated. The objectives of this study were to measure the rates of alpha-ergocryptine epimerization to alpha-ergocryptinine at room temperature and at -40 degrees C, and to measure the rate of ergovaline epimerization to ergovalinine at 37 degrees C. Alpha-ergocryptine tartrate was stable (< 0.5% epimerization) in protic or aprotic solvents when stored at -40 degrees C for 20 to 52 d. At room temperature, alpha-ergocryptine epimerization in chloroform did not occur; epimerization was modest in acetone and acetonitrile (< 5%) but was substantial in methanol (78% by 38 d) and in a 70:30 water methanol mix (47% by 42 d). Ergovaline epimerization to ergovalinine occurred at 37 degrees C in 0.1 M phosphate buffers (pH 3, 7.5, and 9) in 9% aqueous solutions of fetal bovine serum (FBS), and in water, methanol, and acetonitrile. T...
Journal of animal science, 2000
The effects of ractopamine (RAC) and ractopamine stereoisomers (RR, RS, SR, and SS) on cyclic AMP... more The effects of ractopamine (RAC) and ractopamine stereoisomers (RR, RS, SR, and SS) on cyclic AMP (cAMP) production, total protein, and DNA concentrations in mouse skeletal muscle cells (C2C12) were evaluated. The RAC (10 microM) caused an approximately 30% increase in cell number, protein, and DNA concentrations in myoblasts after 48 h; no differences were found in myotubes. The RAC-stimulated increase of these variables in myoblasts was blocked by the presence of equimolar concentrations of propranolol. At a later passage, myoblasts failed to exhibit an increase in cell number, protein, or DNA upon exposure to RAC. Both myoblasts and myotubes increased cAMP production in response to 10 microM RAC. The RAC isomers ranked RR > SR > RS approximately SS in ability to stimulate cAMP production, with essentially no response to SS. The SR produced about 50% of the RR response. Coincubation of propranolol (10 microM) and RAC (10 microM) prevented RAC-stimulated cAMP production in my...
The Journal of nutrition, 1987
Ten pregnant heifers and 10 pregnant cows (three or more pregnancies) were assigned to groups of ... more Ten pregnant heifers and 10 pregnant cows (three or more pregnancies) were assigned to groups of five and fed either the recommended (low) amount of calcium or excess (high) calcium in their diet for 4 wk before parturition to determine the influence of prepartum calcium intake and age on hormonal control of peripartum calcium homeostasis. After parturition all groups received a diet with calcium adequate for lactation. Jugular blood samples from 21, 14, 7, 6, 5, 4, 3, 2, and 1 d prepartum through 0, 1, 2, 3, 5, 7, 14 and 21 d postpartum were assayed for concentration of parathyroid hormone, calcitonin, calcium, magnesium and phosphorus. Heifers and cows receiving high calcium diets had higher calcium and lower parathyroid hormone in blood serum before parturition than animals receiving the low calcium diets. Cows, but not heifers, fed high calcium diets exhibited severe hypocalcemia at parturition, remained hypocalcemic for 3 d and had low serum calcitonin. Regardless of dietary gr...
The Journal of nutrition, 2014
The earlier onset of puberty seen in young American girls has led researchers to question if a ca... more The earlier onset of puberty seen in young American girls has led researchers to question if a causal relation exists between dietary sources of estrogenic compounds and precocious puberty. Using the prepubertal gilt (young female pig) as an animal model, our hypothesis is that feeding beef obtained from cattle receiving growth-promoting steroidal implants postweaning does not alter the onset of puberty or the peripubertal body composition of gilts compared with contemporaries fed nonimplanted "natural" beef or a common meat alternative, tofu. The base diet was formulated using canola meal replacing soybean meal to reduce diet estrogenicity. Feed intake was monitored and controlled to ensure similar intake. Gilts were assigned to treatments based on dam and initial body weight (mean: 24.5 ± 3.20 kg) at 61 d of age. The negative control base diet was supplemented with daily feedings of a cooked patty from nonimplanted steers (natural), from steers that had been treated with...
Journal of Animal Science, Jun 1, 2002
J Agr Food Chem, 2007
A novel preharvest technology that reduces certain pathogenic bacteria in the gastrointestinal tr... more A novel preharvest technology that reduces certain pathogenic bacteria in the gastrointestinal tracts of food animals involves feeding an experimental sodium chlorate-containing product (ECP) to animals 24-72 h prior to slaughter. To determine the metabolism and disposition of the active ingredient in ECP, four male Sprague-Dawley (approximately 350 g) rats received a single oral dose of sodium [36Cl]chlorate (3.0 mg/kg body weight). Urine, feces, and respired air were collected for 72 h. Radiochlorine absorption was 88-95% of the administered dose, and the major excretory route was the urine. Parent chlorate was the major species of radiochlorine present in urine at 6 h (approximately 98%) but declined sharply by 48 h (approximately 10%); chloride was the only other species of radiochlorine detected. Except for carcass remains (4.6% of dose), skin (3.2%), and gastrointestinal tract (1.3%), remaining tissues contained relatively low quantities of radioactivity, and &amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;98% of radiochlorine remaining in the liver, kidney, and skeletal muscle was chloride. Chlorite instability was demonstrated in rat urine and bovine urine. The previously reported presence of chlorite in excreta of chlorate-dosed rats was shown to be an artifact of the analytical methods employed. Results from this study indicate that chlorate is rapidly absorbed and reduced to chloride, but not chlorite, in rats.
Environmental Science Technology, 2010
In Vitro Cell Dev Biol Animal, 2003
Journal of Animal Science
Journal of Nutrition
Ten pregnant heifers and 10 pregnant cows (three or more pregnancies) were assigned to groups of ... more Ten pregnant heifers and 10 pregnant cows (three or more pregnancies) were assigned to groups of five and fed either the recommended (low) amount of calcium or excess (high) calcium in their diet for 4 wk before parturition to determine the influence of prepartum calcium intake and age on hormonal control of peripartum calcium homeostasis. After parturition all groups received a diet with calcium adequate for lactation. Jugular blood samples from 21, 14, 7, 6, 5, 4, 3, 2, and 1 d prepartum through 0, 1, 2, 3, 5, 7, 14 and 21 d postpartum were assayed for concentration of parathyroid hormone, calcitonin, calcium, magnesium and phosphorus. Heifers and cows receiving high calcium diets had higher calcium and lower parathyroid hormone in blood serum before parturition than animals receiving the low calcium diets. Cows, but not heifers, fed high calcium diets exhibited severe hypocalcemia at parturition, remained hypocalcemic for 3 d and had low serum calcitonin. Regardless of dietary group, concentrations of parathyroid hormone and magnesium in serum increased after the first week of lactation. Feed intake during lactation, corrected for metabolic body weight, was similar for both dietary treatments and ages. Milk production per kilogram metabolic body weight was highest during the first week of lactation for cows fed low calcium diets before parturition. There was no correlation between hypocalcemia and loss of calcium in colostrum or milk. Feeding low dietary calcium to cows in the prepartum period was effective in the prevention of severe hypocalcemia at parturition. In contrast, dietary treatment of heifers had no effect on serum calcium concentration at parturition.(ABSTRACT TRUNCATED AT 250 WORDS)
Journal of Animal Science
Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), persistent pol... more Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), persistent pollutants that accumulate in the food chain, pose a risk to humans through consumption of tainted livestock. Clenbuterol, a leanness-enhancing agent, was tested for usefulness in PCDD/F body store reduction through body fat reduction (the predominant site of accumulation). To mimic the situation of contaminated animals, rats were given feed with or without a mixture of PCDD/F (0.6 to 2.7 ng/congener per day) for 10 d, followed by 16 d of feed with or without dietary clenbuterol (2 mg/kg feed). Clenbuterol reduced body fat by 28% (P < 0.05), increased muscle mass by 25% (P < 0.02), and decreased liver mass by 7% (P < 0.02). Although the concentrations of most PCDD/F per gram of fat were slightly increased after clenbuterol treatment, the total amount of PCDD/F that remained in fat was reduced by approximately 30%. Muscle PCDD/F concentrations and total burden were decreased by clenbuterol. In contrast, clenbuterol tended to increase concentration, but not total burden of PCDD/F in livers. One congener known to be rapidly metabolized and excreted, 2,3,7,8-TCDF, was the exception to this increase, decreasing 40% with clenbuterol treatment. This was also the congener that showed the greatest reduction in both fat and muscle. Examination of the ratio of PCDD/F in liver and fat revealed that clenbuterol increased the liver's share of the body burden of PCDD/F, from 38 to 75%. In a remediation/disposal context, these findings would be beneficial if clenbuterol lowered the meat and carcass burden of PCDD/F to safe levels, requiring only livers to be disposed of as hazardous waste.
Journal of Biological Chemistry
In MALME-3M human melanoma cells the polyamine analog N1,N12-bis(ethyl)spermine (BESPM) suppresse... more In MALME-3M human melanoma cells the polyamine analog N1,N12-bis(ethyl)spermine (BESPM) suppresses the key polyamine biosynthetic enzymes, ornithine and S-adenosylmethionine decarboxylase, and increases the polyamine catabolizing enzyme, spermidine/spermine N1-acetyl-transferase (SSAT) by more than 200-fold. In the present study increases in SSAT activity in MALME-3M cells treated with 10 microM BESPM were found to be accompanied by a substantial (up to 45-fold) accumulation of SSAT mRNA. By Northern blot analysis three RNA transcripts were found to hybridize with the coding region of human SSAT cDNA: a minor high molecular weight (approximately 3.5 kilobases) species designated form A and two lower molecular weight species designated forms B and C (approximately 1.5 and approximately 1.3 kilobases, respectively). Form A increased uniformly during BESPM treatment and was most obvious in nuclear RNA preparations. On the basis of size similarity to the transcribing region of the gene and hybridization with the coding region of SSAT cDNA and its prevalence in nuclear mRNA preparations, form A is thought to represent precursor SSAT RNA. Form C is present in control cells and increases steadily during treatment, whereas form B increases transiently during early treatment (1-3 h). By RNase H digestion assay, form B was found to have a 200-base pair longer poly(A) tract and as such may represent a precursor to form C. Accumulation of SSAT mRNA was found to be a result of increased gene transcription and stabilization of SSAT mRNA. Nuclear run-on studies indicated a 2-4-fold increase in the transcription rate of the SSAT gene. As indicated by actinomycin D studies, the SSAT mRNA half-life increased with BESPM treatment from 17 to 64 h. The natural polyamine, spermine, also increased SSAT mRNA (5.5-fold at 24 h) and behaved similarly to BESPM in inducing the appearance of the same three transcript forms. The polyamine was much less effective than the analog at increasing enzyme activity. Lowering intracellular polyamine pools with inhibitors of biosynthesis decreased basal SSAT mRNA levels by at least 70% indicating, that the gene can be down-regulated as well as up-regulated by polyamines. These findings indicate that SSAT represents a unique example of gene expression being positively influenced at the RNA level by polyamines and their analogs.
Dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the envi... more Dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the environmental fate and transport of steroidal estrogens. This study quantified the association of the natural occurring 17beta-estradiol (E2), with the DF and CF isolated from liquid swine manure (LSM), Soil, and LSM and Soil mixtures (Soil+LSM). The appropriate CF and DF size fractions of the Soil, Soil+LSM, and LSM materials were obtained by first filtering through a 0.45 µm filter, which provided the combined DF and CF (DF/CF). The DF/CF from the three media were spiked with radiolabelled (14C) E2, and then ultrafiltrated to isolate the CF (<0.45 mm and > 1 kDa) from the DF (<1 kDa). The average recoveries of the 14C E2 associated with the DF were 67%-72%, 67%-79%, and 76%-78% for the Soil, Soil+LSM and LSM, respectively. For the CF that was retained on the 1 kDa filter, organic carbon (OC) and 14C-E2 were dislodged with subsequent water rinses for all three media. The Soil media...
The effects of ractopamine (RAC) and ractopamine stereoisomers (RR, RS, SR, and SS) on cyclic AMP... more The effects of ractopamine (RAC) and ractopamine stereoisomers (RR, RS, SR, and SS) on cyclic AMP (cAMP) production, total protein, and DNA concentrations in mouse skeletal muscle cells (C2C12) were evaluated. The RAC (10 M) caused an ∼30% in- crease in cell number, protein, and DNA concentrations in myoblasts after 48 h; no differences were found in myotubes. The RAC-stimulated
Purifiedergopeptinealkaloidsareoften used in studies related to tall fescue toxicosis without reg... more Purifiedergopeptinealkaloidsareoften used in studies related to tall fescue toxicosis without regard to epimerization that occurs when ergopeptines are solvated. The objectives of this study were to mea- sure the rates of α-ergocryptine epimerization to α- ergocryptinine at room temperature and at −40°C, and to measure the rate of ergovaline epimerization to ergo- valinine at 37°C. α-Ergocryptine tartrate was stable (<
Ten pregnant heifersand 10 pregnant cows (three or more pregnancies)were assignedto groups of fiv... more Ten pregnant heifersand 10 pregnant cows (three or more pregnancies)were assignedto groups of five and fed either the recommended,(low) amount,of calcium or excess (high) calcium in their diet for 4 wk before parturitionto determine the influenceof prepartum calcium intake and age on hormonal control of peripartumcalcium homeostasis. After parturitionall groupsreceiveda diet with calciumadequatefor lactation.Jugular bloodsamplesfrom 21,14,7, 6, 5,4, 3,
The Science of the total environment, 2014
The dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the ... more The dissolved (DF) and colloidal fractions (CF) of soil and manure play an important role in the environmental fate and transport of steroidal estrogens. The first objective of this study was to quantify the association of 17β-estradiol (E2) with the DF and CF isolated from (i) liquid swine manure (LSM), (ii) a soil:water mixture (soil), and (iii) a LSM:soil:water mixture (Soil+LSM). The appropriate CF and DF size fractions of the Soil, Soil+LSM, and LSM media were obtained by first filtering through a 0.45 μm filter, which provided the combined DF and CF (DF/CF). The DF/CF from the three media was spiked with carbon-14 ([(14)C]) radiolabeled E2 ([(14)C]-E2), and then ultrafiltered to isolate the CF (<0.45 μm and >1 kDa) from the DF (<1 kDa). The average recoveries of the [(14)C] associated with the DF were 67%-72%, 67%-79%, and 76%-78% for the Soil, Soil+LSM and LSM, respectively. For the CF that was retained on the 1 kDa filter, organic carbon and [(14)C]-E2 were dislodge...
Environmental science & technology, Jan 15, 2008
Endocrine disrupting chemicals (EDCs) impair living organisms by interfering with hormonal proces... more Endocrine disrupting chemicals (EDCs) impair living organisms by interfering with hormonal processes controlling cellular development Reduction of EDCs in water by an environmentally benign method is an important green chemistry goal. One EDC, 17alpha-ethinylestradiol (EE2), the active ingredient in the birth control pill, is excreted by humans to produce a major source of artificial environmental estrogenicity, which is incompletely removed by currenttechnologies used by municipal wastewater treatment plants (MWTPs). Natural estrogens found in animal waste from concentrated animal feeding operations (CAFOs) can also increase estrogenic activity of surface waters. An iron-tetraamidomacrocyclic ligand (Fe-TAML) activator in trace concentrations activates hydrogen peroxide and was shown to rapidly degrade these natural and synthetic reproductive hormones found in agricultural and municipal effluent streams. On the basis of liquid chromatography tandem mass spectrometry, apparent half-...
Journal of animal science, 2002
Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), persistent pol... more Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), persistent pollutants that accumulate in the food chain, pose a risk to humans through consumption of tainted livestock. Clenbuterol, a leanness-enhancing agent, was tested for usefulness in PCDD/F body store reduction through body fat reduction (the predominant site of accumulation). To mimic the situation of contaminated animals, rats were given feed with or without a mixture of PCDD/F (0.6 to 2.7 ng/congener per day) for 10 d, followed by 16 d of feed with or without dietary clenbuterol (2 mg/kg feed). Clenbuterol reduced body fat by 28% (P < 0.05), increased muscle mass by 25% (P < 0.02), and decreased liver mass by 7% (P < 0.02). Although the concentrations of most PCDD/F per gram of fat were slightly increased after clenbuterol treatment, the total amount of PCDD/F that remained in fat was reduced by approximately 30%. Muscle PCDD/F concentrations and total burden were decreased by clen...
Journal of animal science, 2002
Purified ergopeptine alkaloids are often used in studies related to tall fescue toxicosis without... more Purified ergopeptine alkaloids are often used in studies related to tall fescue toxicosis without regard to epimerization that occurs when ergopeptines are solvated. The objectives of this study were to measure the rates of alpha-ergocryptine epimerization to alpha-ergocryptinine at room temperature and at -40 degrees C, and to measure the rate of ergovaline epimerization to ergovalinine at 37 degrees C. Alpha-ergocryptine tartrate was stable (< 0.5% epimerization) in protic or aprotic solvents when stored at -40 degrees C for 20 to 52 d. At room temperature, alpha-ergocryptine epimerization in chloroform did not occur; epimerization was modest in acetone and acetonitrile (< 5%) but was substantial in methanol (78% by 38 d) and in a 70:30 water methanol mix (47% by 42 d). Ergovaline epimerization to ergovalinine occurred at 37 degrees C in 0.1 M phosphate buffers (pH 3, 7.5, and 9) in 9% aqueous solutions of fetal bovine serum (FBS), and in water, methanol, and acetonitrile. T...
Journal of animal science, 2000
The effects of ractopamine (RAC) and ractopamine stereoisomers (RR, RS, SR, and SS) on cyclic AMP... more The effects of ractopamine (RAC) and ractopamine stereoisomers (RR, RS, SR, and SS) on cyclic AMP (cAMP) production, total protein, and DNA concentrations in mouse skeletal muscle cells (C2C12) were evaluated. The RAC (10 microM) caused an approximately 30% increase in cell number, protein, and DNA concentrations in myoblasts after 48 h; no differences were found in myotubes. The RAC-stimulated increase of these variables in myoblasts was blocked by the presence of equimolar concentrations of propranolol. At a later passage, myoblasts failed to exhibit an increase in cell number, protein, or DNA upon exposure to RAC. Both myoblasts and myotubes increased cAMP production in response to 10 microM RAC. The RAC isomers ranked RR > SR > RS approximately SS in ability to stimulate cAMP production, with essentially no response to SS. The SR produced about 50% of the RR response. Coincubation of propranolol (10 microM) and RAC (10 microM) prevented RAC-stimulated cAMP production in my...
The Journal of nutrition, 1987
Ten pregnant heifers and 10 pregnant cows (three or more pregnancies) were assigned to groups of ... more Ten pregnant heifers and 10 pregnant cows (three or more pregnancies) were assigned to groups of five and fed either the recommended (low) amount of calcium or excess (high) calcium in their diet for 4 wk before parturition to determine the influence of prepartum calcium intake and age on hormonal control of peripartum calcium homeostasis. After parturition all groups received a diet with calcium adequate for lactation. Jugular blood samples from 21, 14, 7, 6, 5, 4, 3, 2, and 1 d prepartum through 0, 1, 2, 3, 5, 7, 14 and 21 d postpartum were assayed for concentration of parathyroid hormone, calcitonin, calcium, magnesium and phosphorus. Heifers and cows receiving high calcium diets had higher calcium and lower parathyroid hormone in blood serum before parturition than animals receiving the low calcium diets. Cows, but not heifers, fed high calcium diets exhibited severe hypocalcemia at parturition, remained hypocalcemic for 3 d and had low serum calcitonin. Regardless of dietary gr...
The Journal of nutrition, 2014
The earlier onset of puberty seen in young American girls has led researchers to question if a ca... more The earlier onset of puberty seen in young American girls has led researchers to question if a causal relation exists between dietary sources of estrogenic compounds and precocious puberty. Using the prepubertal gilt (young female pig) as an animal model, our hypothesis is that feeding beef obtained from cattle receiving growth-promoting steroidal implants postweaning does not alter the onset of puberty or the peripubertal body composition of gilts compared with contemporaries fed nonimplanted "natural" beef or a common meat alternative, tofu. The base diet was formulated using canola meal replacing soybean meal to reduce diet estrogenicity. Feed intake was monitored and controlled to ensure similar intake. Gilts were assigned to treatments based on dam and initial body weight (mean: 24.5 ± 3.20 kg) at 61 d of age. The negative control base diet was supplemented with daily feedings of a cooked patty from nonimplanted steers (natural), from steers that had been treated with...