Plasma concentrations of prolactin, growth hormone, and luteinizing hormone in steers administered ergotamine or ergonovine

This research investigated whether ergot alkaloids associated with endophyte-infected tall fescue could alter plasma concentrations of pituitary hormones that regulate biological processes related to cattle performance. Seven Angus yearling steers received single i.v. injections of ergotamine tartrate, ergonovine maleate, or saline vehicle in a simple cross-over design. Each steer was given a different compound each week. Blood samples were collected at 15-min intervals for 45 min before and 240 min after treatments to assess plasma concentrations of prolactin, growth hormone, and LH. Respiratory rates were measured hourly to ascertain a systemic effect. Ambient temperature averaged 34 degrees C during data collection. Treatment x time was a significant source of variation for respiration rate and plasma concentrations of each hormone evaluated. Respiration rates were higher for ergonovine than for saline (P < .02) and ergotamine (P < .07) 30 min after treatment, but they were higher (P < .05) for ergotamine than for ergonovine and saline by 210 min after treatment. Both alkaloids transiently elevated (P < .01) plasma growth hormone concentrations compared with before alkaloid treatment and after saline treatment. Ergotamine reduced (P < .01) plasma concentrations of prolactin and LH throughout the 120-min period after treatment compared with concentrations before ergotamine treatment and after saline treatment. Ergonovine lowered (P < .01) prolactin concentrations for a shorter time than ergotamine and did not affect mean LH concentrations. Results indicated that ergot alkaloids implicated as contributing agents to fescue toxicosis can alter plasma concentrations of pituitary hormones important to cattle production.     

Oral and parenteral vaccination of mice with protein-ergotamine conjugates and evaluation of protection against fescue toxicosis

Acremonium coenophialum produces ergopeptide alkaloids in tall fescue (Festuca arundinacea Schreb.). These ergot alkaloids decrease serum alkaline phosphatase (ALP) activity, serum cholesterol and prolactin concentrations, as well as average daily gains (ADG) in cattle. The objective of this study was to evaluate the protection of anti-ergotamine antibodies induced by either oral or parenteral vaccination with protein-ergotamine conjugates or passive vaccination with anti-ergovaline, monoclonal antibodies in a murine model of fescue toxicosis. Ergotamine (EG) was conjugated to bovine serum albumin (BSA) and cholera toxin subunit B (CTB) by the Mannich reaction. Mice were blocked based on weight and randomly allocated into five groups of 10 mice each. Treatment groups were as follows: (1) group vaccinated intraperitoneally (ip) with a BSA-EG conjugate and fed an endophyte-infected (EI) fescue diet (BSA-EG group); (2) group orally vaccinated with a CTB-EG conjugate mixed with free cholera toxin (CT) and fed an EI fescue diet (CTB-EG group); (3) nonvaccinated group fed an EI fescue diet (EI group); (4) group passively vaccinated with anti-ergovaline, monoclonal antibodies and fed an EI fescue diet (MoAB group); and (5) nonvaccinated group fed an endophyte-free (EF) fescue diet (EF group). The EI diet contained 1.5 ppm of Ergovaline (EV), whereas no EV was detected in the EF diet.Respective diets were similar upon nutritional analysis. Unvaccinated mice in the EI group exhibited features of fescue toxicosis as indicated by decreased serum ALP activity and cholesterol, and decreased weight gain as compared to mice in the EF group. Antibodies against EG and EV were present in sera of mice in the BSA-EG and MoAB groups, respectively. Mice orally vaccinated with the CTB-EG conjugate developed secretory IgA (sIgA) antibodies and short-lived, systemic IgG responses against EG. Weight gains were increased in the BSA-EG and CTB-EG groups and tended to be increased in the MoAB group vs. the unvaccinated EI group. Serum ALP activity was decreased in the BSA-EG and MoAB groups as compared to the EF group. Serum ALP activity was further decreased in the BSA-EG vaccinated group as compared to the EI group. Cholesterol concentrations were decreased in the EI, BSA-EG and MoAB groups as compared to the EF group. Prolactin concentrations were similar in all groups.     

Effect of ergotamine and ergonovine on plasma concentrations of thyroid hormones and cortisol in cattle

Plasma samples from two experiments were processed to determine whether ergot alkaloids associated with endophyte-infected tall fescue altered peripheral thyroxine (T4), triiodothyronine (T3), or cortisol concentrations in cattle. In Exp. 1, seven Angus steers (294 kg) received i.v. bolus injections of saline (SAL), ergonovine maleate (7 mg; EM), or ergotamine tartrate (7 mg; ET) at weekly intervals, and they received all treatments during the study. Blood was sampled every 15 min for 5 h, and treatments were given after h 1. Mean ambient temperature was 34 degrees C. Treatment x time affected plasma concentrations of T3 (P < .05) and of cortisol (P < .001) but not that of T4 (P > .2). Plasma T3 concentrations were not affected by SAL, whereas concentrations increased (P < .01) after either EM or ET treatment. Plasma cortisol concentrations were not altered by SAL or EM, but they were increased (P < .001) by ET treatment. In Exp. 2, six Holstein cows (499 kg) nursing calves received a bolus i.v. injection of SAL, EM (9.5 mg), or ET (9.5 mg) per estrous cycle, and all treatments were given over three cycles. Blood was sampled every 20 min for 5 h; treatments were given after h 1. Mean ambient temperature was 26 degrees C. Treatment x time affected T3 (P = .08) and cortisol (P < .001) and tended to influence (P = .16) T4 concentrations. Plasma T3, T4, and cortisol concentrations were not influenced by SAL treatment. Plasma T3 was higher (P < or = .01) after EM or ET treatment compared with pretreatment concentrations. Concentrations of T4 during the 4 h after EM and ET were increased (P < .001) compared with pretreatment. Plasma cortisol concentrations were not altered by EM but were increased (P < .001) by ET. Ergot alkaloids implicated as contributing agents to fescue toxicosis alter plasma concentrations of hormones important to metabolic and thermoregulatory functions in cattle.     

Evaluation of humoral immune responses in cattle grazing endophyte-infected or endophyte-free fescue

Anecdotal reports suggest cattle with fescue toxicosis may not respond to vaccination and thus, experience increased incidence of Bovine Respiratory Disease Complex (BRDC) when shipped to feedlots. Fescue toxicosis causes hypoprolactemia in cattle. Hypoprolactemia decreases humoral immune responses in mice. Therefore, a study was conducted to compare the magnitude of primary and secondary humoral immune responses against specific antigens in cattle grazing endophyte-infected or endophyte-free fescue. Angus steers were blocked by weight and allocated into four groups. Two groups grazed endophyte-infected (EI) fescue and the other two groups grazed endophyte-free (EF) fescue. All steers were injected IM on d 0 and 21 with lysozyme without adjuvant and concanavalin. A (Con A) with sheep red blood cells (SRBC) in incomplete adjuvant of Freund. Steers were bled on days 0, 21 and 35 post-vaccination. Average daily gains (ADG), alkaline phosphatase (ALP) activity, cholesterol concentrations, rectal temperatures, and serum prolactin concentrations were measured to confirm fescue toxicosis in steers grazing EI fescue. Antibodies to Con A and SRBC were determined by ELISA and hemagglutination assay, respectively. The ADG were decreased for the EI group during the first month. Rectal temperature were elevated and serum prolactin concentrations were decreased in the EI group. Cholesterol and ALP concentrations also were decreased in the EI group. Primary and secondary immune responses against Con A tended to be increased and were increased against SRBC in the EI group. Antibodies against lysozyme were not induced in either group. In conclusion, cattle grazing EI fescue mounted similar humoral immune responses to vaccination, despite hypoprolactemia, as cattle grazing EF fescue. Increases in bovine respiratory disease in cattle maintained on EI fescue probably is not associated with lack of humoral immune response to vaccination protocols as a result of fescue toxicosis.     

An evidence-based approach to pressure- and volume-limited ventilation strategies

To assess the efficacy of ammoniation in the detoxification of endophyte-infected tall fescue (Festuca arundinacea Schreb), 40 male Harlan Sprague-Dawley rats were randomly assigned to the following four treatments for 28 d: endophyte-free (E-), endophyte-infected (E+), ammoniated (2% dry matter basis, 7 d) endophyte-free (AE-), and ammoniated endophyte-infected (AE+) tall fescue seed. Total pyrrolizidine alkaloid (N-acetyl and N-formyl loline) and ergovaline contents of endophyte-infected fescue seed were reduced 24 and 54%, respectively, by ammoniation. Endophyte-infected treatment groups had lower (P < 0.01) daily feed intakes (DFI), daily weight gains (DWG), feed efficiencies, and primary serum hemagglutination titers to sheep red blood cell (SRBC) immunization than endophyte-free treatment groups. Performance parameters were higher (P < 0.01) for ammoniated diets in comparison to non-ammoniated diets; however, anti-SRBC titers were not significantly different. When compared to the E+ diet, the AE+ diet increased (P < 0.01) DFI (24%), DWG (41%) and feed efficiency (13%).     

Influence of Neotyphodium coenophialum on copper concentration in tall fescue

Poor performance of livestock that graze tall fescue (Festuca arundinacea Schreb.) has been associated with the endophyte fungus Neotyphodium coenophialum [Morgan-Jones and Gams] Glenn, Bacon, and Hanlin). Recent evidence suggests lowered Cu status and a depression of Cu-related immune function in steers that graze endophyte-infected (E+) tall fescue. Greenhouse and field studies investigated relationships between the endophyte and Cu concentrations in tall fescue. Seventeen infected 'Kenhy' clones were divided, and one plant of each pair was treated three times with Benomyl to remove the endophyte (E-). Plants were watered with nutrient solution in a greenhouse for 6 mo before sampling. Copper concentrations were greater (P < .001) in E- than in E+ clones (3.4 vs 2.8 microg/g; SE, .06). In the second greenhouse experiment, genetically similar E+ and E- 'Kentucky'-31 (KY-31) and 'Georgia Jessup' were grown from seed and fertilized with nutrient solution to produce mature plants. Copper concentrations were higher (P < .05) in E- than in E+ tall fescue (8.6 vs 7.6 microg/g; SE, .3). In a field plot experiment in Texas, E+ and E- KY-31 were grown with 0, 50, and 100% replacement of potential evapotranspiration. By September, Cu concentrations were higher (P < .05) in E- than in E+ tall fescue (7.3 vs 6.6 microg/g; SE, .2). In pasture experiments, KY-31 E+ (> 70% infection level) and E- (< 5% infection level) tall fescue were grown in Virginia at two locations with three rates of N fertilizer. Copper concentrations were higher (P < .05) in E- than in E+ tall fescue (4.8 vs 4.5 microg/g; SE, .1) and increased (P < .01) linearly in response to N. Our data demonstrate that the presence of the endophyte is associated with lower Cu concentrations in tall fescue, which may contribute to lowered Cu status in animals and thus contribute to the etiology of fescue toxicity.     

Comparison of two ammoniation procedures to reduce the toxicity of endophyte-infected tall fescue seed fed to rats

To determine the effect of extending the duration of ammonia (2% dry matter basis) treatment ti'om 1 to 5 wk on the toxicity of endophyte-infected tall fescue seed, 60 male Harlan Sprague-Dawley rats were randomly assigned to the following six treatments during a 28-d trial: endophyte-free (E-), endophyte-infected (E+), 1 wk ammoniated endophyte-fee (1AE-), 1 wk ammoniated endophyte-infected (1AE+), 5 wk ammoniated endophyte-free (5AE-), and 5 wk ammoniated endophyte-infected (5AE+) tall fescue seed. The concentration of total pyrrolizidine alkaloids (N-acetyl and N-formyl loline) or E+ rescue was reduced from 4203 12 g/g to 3009 and 2533 I-tg/g by the 1AE+ and 5AE+ treatments, respectively. Ergovaline was lowered from 3.77 to 1.57 12 g/g by 1AE+ and eliminated by 5AE+. Endophyte-infected treatment groups had depressed (P < 0.0001) dally feed intakes (DFI), daily weight gains (DWG), feed efficiencies (G/F), primary antibody responses, and T cell and B cell mitogenic responses than endophyte-free treatment groups. Ammoniation of endophyte-infected rescue seed improved DFI and DWG (P < 0.0001) and G/F (P < 0.05); however, there was no difference in performance criteria between the 1-wk and 5-wk ammoniation treatments. Endophyte-induced depressions in immune function were not alleviated by ammoniation.     

Enhancing activity of mycobacterial cell-derived adjuvants on immunogenicity of recombinant human hepatitis B virus vaccine

In a previous study, we demonstrated that a lipophilic derivative of muramyl dipeptide [MDP-Lys(L18)] augmented antibody response to recombinant human hepatitis B surface antigen (rhHBsAg) when it was co-immunized with rhHBsAg solubilized in PBS. Here, we examined adjuvant activity of two bacterial cell-derived adjuvants such as Bacillus Calmette-Guérin cell wall skeleton (BCG-CWS) and trehalose-6,6'-dimycolate (TDM), to enhance immunogenicity of rhHBsAg, comparing their activity with that of MDP-Lys(L18). In an animal model where mice were immunized subcutaneously (s.c.) with rhHBsAg (25 micrograms/mouse) admixed with 100 micrograms/mouse of BCG-CWS (Vac/BCG-CWS) or 50 micrograms/mouse of TDM (Vac/TDM) in o/w emulsion formulation, both mice immunized with Vac/BCG-CWS and Vac/TDM showed higher antibody titres to HB antigen than those of mice immunized with the recombinant vaccine alone. The activity of BCG-CWS and TDM to enhance antibody induction seemed to be almost the same with that of MDP-Lys(L18). Furthermore, the enhanced antibody response raised by these adjuvants was shown to be due to high titres of HB antigen-specific IgG1. In addition, the activity of these three adjuvants to enhance antibody response was shown to be higher than that of the present clinical vaccine, aluminium hydroxide-attached rhHBsAg (rhHBsAg-alum). In an analysis of delayed-type hypersensitivity (DTH) reaction where mice were immunized with rhHBsAg admixed with or without each adjuvant in o/w emulsion and followed by intrafootpad (i.f.) injection of rhHBsAg 4 weeks after immunization, mice immunized with Vac/BCG-CWS and Vac/TDM as well as Vac/MDP-Lys(L18) showed a significant increment of swelling reaction. These results suggest that BCG-CWS, TDM and MDP-Lys(L18) are potential adjuvants to enhance the immunogenicity of rhHBsAg to induce humoral and cellular responses.     

The role of calcium ions in DEAE-dextran-induced stimulation of neutrophil migration

The polycation DEAE-dextran caused a strong enhancement of non-directed migration of rabbit peritoneal neutrophils. The activating effect on migration was completely annulled in the presence of the polyanion poly-D-glutamic acid, indicating that the effect depended on the positive charge of the macromolecule. Chemotaxis activated by the chemotactic peptide fMLP was only slightly affected by the polycation. In contrast with fMLP-activation, stimulation of migration by DEAE-dextran was dependent on the presence of extracellular Ca2+. DEAE-dextran also stimulated migration of electroporated neutrophils. The stimulation was absent when calcium was not present; the increase of migration was strongest at Ca(2+)-concentrations between 100 nM and 1 microM Ca2+. This indicates that the requirement for extracellular Ca2+ in intact cells is a reflection of the intracellular requirement. Several types of calcium blockers gave a moderate inhibition of DEAE-dextran activated migration. Activation of migration by DEAE-dextran of electroporated neutrophils was completely inhibited by calcium channel blockers, at very low concentrations. The results suggest that both Ca(2+)-fluxes across the plasma membrane and Ca2+ from intracellular stores are required for DEAE-activated migration, and that the calcium from the intracellular source is required on a place where the extracellular Ca2+ has no, or limited, admittance.     

Efficacy of a bovine Staphylococcus aureus vaccine using interleukin-2 as an adjuvant

The purpose of this study was to examine the efficacy of a vaccination protocol using recombinant bovine interleukin-2 (rBoIL-2) as an adjuvant with a Staphylococcus aureus vaccine. Holstein dairy cows were immunized with a S. aureus vaccine in conjunction with either saline solution (n = 3), Freund's incomplete adjuvant (FIA; n = 3) or rBoIL-2 (n = 3). Whey and serum were analysed for antibody titer to specific S. aureus antigens. Isolated blood mononuclear cells (BMC) were examined for their ability to proliferate and to produce interleukin-2 (IL-2) and interferon (IFN) after either mitogenic or antigenic stimulation in vitro. Efficacy of the vaccination protocols was assessed by challenging experimental animals intramammarily with 100 colony forming units of S. aureus. Regardless of treatment, all cows exhibited similar serum antibody titers to S. aureus pseudocapsule. Cows treated with saline exhibited a significant increase in serum alpha-toxin antibody titer when compared to levels observed in FIA and rBoIL-2-treated cows. However, cows receiving rBoIL-2 treatment exhibited significantly higher lacteal pseudocapsule antibody titer compared to the other adjuvant groups. Administration of rBoIL-2 did not enhance BMC proliferative responses to the mitogens concanavalin A (ConA), phytohemagglutinin (PHA), pokeweed mitogen (PWM) or interleukin-2 (IL-2) when compared to FIA or saline treated cows. Although cows receiving rBoIL-2 treatment exhibited enhanced cytokine production upon antigenic stimulation, efficacy of the vaccination protocol was inferior compared to the protection offered by saline treatment.     

Mortality of horn fly (Diptera: Muscidae) larvae in bovine dung supplemented with loline alkaloids from tall fescue

Larvae of arthropod ectoparasites of livestock, such as the horn fly, Haematobia irritans (L.), may be exposed to acyl-loline alkaloids in dung of ruminant livestock ingesting herbage of the tall fescue (Festuca arundinacea Schreb.)-endophyte association [Neotyphodium coenophialum (Morgan-Jones & W. Gams) Glenn, Bacon & Hanlin comb. nov.]. Biological activity of alkaloid-supplemented bovine dung was assayed by growth, development, and survival of 1st instars of horn fly. An extract from tall fescue seed, containing N-formyl loline (NFL), N-acetyl loline (NAL), and loline (59:21:20 by mass, respectively) caused 100% mortality of horn fly larvae when dung was supplemented at > or = 100 micrograms/g. Probit analysis of data corrected for natural mortality indicated a LD50 of 30 micrograms/g (95% fidicial limits: 20-49 micrograms/g). When horn fly larvae were introduced to dung supplemented with up to 50 microM of acyl-loline derivatives, mortality of larvae varied significantly between alkaloids (P < 0.0001). Probit analysis indicated that NFL [LD50: 34 microM (95% fidicial limits: 3-53 microM)] was more toxic than NAL [LD50: 46 microM (0-83 microM)], and that loline hydrochloride was not toxic.     

Immunological studies on the original endotoxin protein (OEP) of Pseudomonas aeruginosa. Adjuvant effect of OEP in vivo

OEP--Original Endotoxin Protein--is a protein moiety of endotoxin of Pseudomonas aeruginosa. An adjuvant action of OEP was investigated in mice immunized with sheep red blood cells (SRBC). Several features characteristic of the adjuvant action of OEP have been revealed; OEP shows no effect on simultaneous treatment with the antigen, and is most effective on successive treatments given after SRBC. The effective dosages of OEP as an adjuvant were in the range of 10 to 100 mug per mouse. Experimental data suggested that OEP might enhance the antibody production in its early phase. The adjuvant action of OEP was lost in mice pretreated with large dosage of OEP; OEP-tolerance could be induced to its adjuvant action. The mechanism of the adjuvant action of OEP was discussed comparing with other adjuvants.     

Ingestional aversion learning in preweanling rats.

In 4 experiments, ingestional aversions were conditioned in 12- and 15-day-old Sprague-Dawley rats by infusing a .5% solution of saccharin into the oral cavity and following this oral infusion by the injection of lithium chloride. At both ages, Ss for which the saccharin exposure was followed by lithium injection within 2–3 min drank less when the saccharin solution was again presented by oral infusion 12 hrs later; such suppressions of intake were not observed in Ss that previously received the saccharin and lithium in an unpaired fashion (Exps I and III). Ingestional aversions were also learned by 12-day-olds when a 30-min interval was introduced between saccharin exposure and lithium toxicosis but not when toxicosis was delayed by 120 min (Exp II). In contrast, 15-day-olds learned aversions with both the 30- and 120-min-delay intervals (Exp III). Despite the absence of long-delay learning in 12-day-olds, ingestional aversions conditioned at 12 days of age were retained for 2 wks (Exp IV). Results provide further evidence of the associative abilities of neonatal rats and illustrate a developmental aspect of long-delay learning. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Angiotensin-converting enzyme gene polymorphism is associated with coronary heart disease in non-insulin-dependent diabetic patients evaluated for 9 years

OBJECTIVES: To assess effects of vaccination against fescue toxicosis on weight gain, serum prolactin and cholesterol concentrations, and alkaline phosphatase (ALP) activity in mice fed an endophyte-infected (EI) or endophyte-free (EF) fescue diet. ANIMALS: 50 six-week-old male BALB/c mice. PROCEDURE: Mice were randomly allocated to the following 5 groups: 1, vaccinated intraperitoneally with a bovine serum albumin-ergotamine (EG) conjugate and fed an EI fescue diet; 2, orally vaccinated with cholera toxin (CT) subunit B-EG conjugate mixed with free CT and fed an EI fescue diet; 3, not vaccinated and fed an EI fescue diet; 4, passively vaccinated with monoclonal antibodies specific for ergovaline (EV) and fed an EI fescue diet; and 5, not vaccinated and fed an EF fescue diet. RESULTS: Antibodies against EG and EV were in serum of mice of groups 1 and 4, respectively. Secretory IgA and IgG coproantibodies against EG were induced in mice of group 2. Weight increased in groups 1 and 2 and tended to be increased in group 4 versus group 3. Prolactin concentration was similar in all groups; cholesterol concentration was decreased in groups 1, 3, and 4, compared with group 5. Compared with that in group 5, serum ALP activity decreased in groups 1 and 4 and was further decreased in group 1, compared with that in groups 2 and 3; it was negatively correlated with anti-EG titer. CONCLUSIONS AND CLINICAL RELEVANCE: Induction of anti-EG antibodies and administration of EV monoclonal antibodies tended to increase short-term weight gain in this murine model of fescue toxicosis. However, systemic IgG antibodies against EG or EV antibodies were not protective against decreases in serum ALP activity and cholesterol concentrations. Clinical significance of decreased ALP activity associated with vaccination is unknown, but represents a worsening of a response often associated with fescue toxicosis in cattle.     

Influence of adjuvants on the induction of autoantibodies to the thyrotropin receptor

To determine the influence of adjuvant on the induction of antibodies to thyrotropin receptor (TSHR), we immunized BALB/c mice with a extracellular domain of the TSHR (ETSHR) protein in complete Freund's adjuvant (CFA), Titer Max (TM) and Gerbu. Similarly, control groups of mice were immunized with bovine serum albumin (BSA) in each of the different adjuvants. As determined by ELISA, ETSHR given along with CFA elicited high titers of antibodies to ETSHR which were mainly restricted to the IgG1 subclass. Mice immunized with ETSHR in TM also developed high titers of anti-ETSHR antibodies but had higher levels of both IgG1 and IgG2a. However, immunization with ETSHR in Gerbu resulted in low titers of antibodies, restricted to IgG1 subclass. Immunization of mice with BSA in each of the three adjuvants induced higher antibody titers to BSA. The subclass of antibodies in mice immunized with BSA in CFA and TM were predominantly IgG1 and IgG2a with lower levels of IgG2b, whereas in Gerbu treated group, antibody to BSA was restricted to IgG1 subclass. Analysis of specificity of antibodies against ETSHR, in mice immunized with ETSHR, revealed that irrespective of the adjuvant used, the dominant reactivity was against peptide 1 (AA 22-41) with weaker reactivity against several other. peptides. The only exception was in mice immunized with ETSHR in TM which also showed significant reactivity against peptide 23 (AA 352-371). Mice immunized with the ETSHR in CFA or in TM showed elevated levels of serum TSH binding inhibitory immunoglobulins (TBII). However, mice immunized with ETSHR in Gerbu, which had lower titers of antibodies to ETSHR, showed normal TBII levels. These studies showed that adjuvant composition could influence the titer, subclass and fine specificity of antibodies to ETSHR which in turn could affect the development of TBII activity.     

Monocyte immune cell response and copper status in beef steers that grazed endophyte-infected tall fescue

A 3-yr study was conducted to evaluate immune response and Cu status of yearling beef steers as a consequence of grazing tall fescue (Festuca arundinacea Schreb.) infected (E+) with the endophyte fungus Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin). During a preliminary study in 1994, 24 weanling Angus and Angus x Hereford steers were blocked by breed and weight (initial BW 271 kg; SD 25) and were randomized to E+ and low endophyte (E-) fescue in pastures at Glade Spring, VA. Grazing began in April and was discontinued in July. In 1995 and 1996, 24 weanling Angus and Angus x Hereford steers (initial BW 249 kg, SD 20 and 240 kg, SD 15, respectively) were randomized to the E+ and E- pastures at Glade Spring during each year. Grazing began in April and continued until September in 1995 and October in 1996. In 1994, steers that grazed E+ fescue exhibited lower (P < .05) phagocytic activity, major histocompatibility complex (MHC) class II expression, ceruloplasmin, and serum Cu than steers that grazed E- tall fescue. During 1995, steers grazing E+ fescue had lower (P < .05) phagocytic activity and MHC class II expression than steers that grazed E- fescue. In 1996, one-half of the steers within each paddock received a Cu oxide bolus at the beginning of the grazing season. During 1996, phagocytic activity was lower (P < .01) and MHC class II expression tended (P < .07) to be lower in steers that grazed E+ tall fescue than in steers that grazed E- tall fescue. Copper supplementation increased (P < .05) MHC class II expression in July regardless of endophyte status over nonsupplemented steers. Steers that grazed E- tall fescue had higher (P < .05) plasma or serum Cu concentrations than steers that grazed E+ tall fescue in each year of the study. These data indicate that the endophyte compromised the immune function of grazing steers, and the data suggest a relationship with depressed Cu status.     

2-Buten-4-olide (2-B4O) inhibits experimental allergic encephalomyelitis (EAE) in Lewis rats

Starvation is well known to induce immune suppression. Moreover, the concentration of 2-B4O, an endogenous sugar acid, is elevated in the circulation during starvation. To determine if these events are related, the influence of 2-B4O on experimental allergic encephalomyelitis (EAE) in Lewis rats, a model of human multiple sclerosis (MS), was studied. EAE, characterized by paralysis of hind legs, was induced by immunization with residues 68 to 84 (MB 68-84) of the guinea pig myelin basic protein (MBP) in complete adjuvant H37Ra. Interestingly, the daily administration of 2-B4O intraperitoneally from the day of MB 68-84 immunization (day 0) to day 20 dramatically suppressed the clinical severity of EAE. The daily administration of 2-B4O intraperitoneally from day 0 to day 7 also markedly reduced the clinical symptoms of EAE. In fact, passively induced EAE, using Con A activated spleen cells from rats immunized with MB 68-84 in H37Ra, was also inhibited by daily administration of 2-B4O. Histological examination confirmed clinical findings and revealed that mononuclear cell infiltration into the central nervous system was significantly inhibited by 2-B4O. To clarify the mechanism(s) responsible for suppression of EAE, the effects of 2-B4O on the immune responses to MB 68-84 were examined. When rats were treated daily with 2-B4O for 15 days after immunization with MB 68-84 in H37Ra, the delayed-type hypersensitivity (DTH) response to MB 68-84 was significantly reduced in 2-B4O treated rats as compared with saline treated rats. The proliferative response to MB 68-84 of spleen cells from 2-B4O treated rats was also significantly lower than that of saline treated rats. Our data demonstrate that 2-B4O has the potential to suppress autoimmune responses in both inductive and effector phases. 2-B4O may have significant potential to treat autoimmune diseases.     

Soluble proteins modified with acetaldehyde and malondialdehyde are immunogenic in the absence of adjuvant

Recent studies have shown that the alcohol metabolites malondialdehyde and acetaldehyde can combine to form a stable adduct (MAA) on proteins. This adduct has been detected in the livers of rats chronically consuming ethanol, and serum antibodies to MAA have been observed at significantly higher concentrations in ethanol-fed when compared with pair-fed or chow-fed control rats. More recently, preliminary studies have strongly suggested that the MAA adduct is capable of stimulating antibody responses to soluble proteins in the absence of adjuvants. The antibodies produced recognize either the MAA epitope or the carrier protein itself. Therefore, it was the purpose of this study to examine the potential immunogenicity of MAA-modified exogenous proteins in the absence of adjuvants. Balb/c mice were immunized in the presence or absence of adjuvant with different concentrations of unmodified or MAA-modified proteins. The antibody response to both the MAA epitope and unmodified protein epitopes were determined by ELISA. In the absence of adjuvant, significant antibody responses were induced to both the MAA epitope and nonmodified protein epitopes. Smaller immunizing doses of MAA-protein conjugate favored the production of antibodies to nonmodified proteins, whereas larger doses induced a strong anti-MAA response. In studies to begin determining a mechanism for the specificity of the response in the absence of adjuvants, peritoneal macrophages were found to bind and degrade MAA-adducted proteins through the use of a scavenger receptor. This indicated that MAA-adducted proteins may be specifically taken up and epitopes presented to the humoral immune system in the absence of adjuvants. Importantly, these are the first data showing that an alcohol-related metabolite can induce an antibody response in the absence of adjuvant and suggesting a mechanism by which antibody to the MAA adduct or its carrier (exogenous or endogenous) proteins may be generated in vivo.     

Effect of chromium picolinate on growth and serum and carcass traits of growing-finishing pigs

Three experiments were conducted to evaluate chromium picolinate (CrPic) in growing-finishing pigs. Treatments were replicated four times within each experiment with three pigs per replicate in Exp. 1 and four pigs per replicate in Exp. 2 and 3. Average initial weights were 37.8, 30.5, and 22.4 kg in Exp. 1, 2, and 3, respectively. In Exp. 1, the basal corn-soybean meal diet (B, 120% NRC Lys) was supplemented with 0, 25, 50, 100, or 200 ppb of Cr from CrPic. Daily gain was increased (Cr cubic, P < .02) and serum cholesterol decreased (Cr cubic, P < .08) by addition of CrPic. In Exp. 2, the basal diet was supplemented with 0, 100, 200, 400, or 800 ppb of Cr from CrPic. Daily gain and ADFI were decreased (Cr linear, P < .05) by CrPic. Serum cholesterol also was decreased (Cr quadratic, P < .05) by CrPic. Longissimus muscle area (LMA) and percentage of muscling (MUS) were increased (Cr quadratic, P < .01) and 10th rib fat (TRF) was decreased (Cr quadratic, P < .01) by CrPic. In Exp. 3, pigs were allotted to the following treatments: 1) B, 2) B + 1,467 ppb of picolinate (Pic), 3) B + 200 ppb of Cr from CrCl3.6H2O, 4) B + 1,467 ppb of Pic + 200 ppb of Cr from CrCl3.6H2O, 5) B + 100 ppb of Cr from CrPic, or 6) B + 200 ppb of Cr from CrPic. Longissimus muscle area and MUS were increased (P < .01) and TRF decreased (P < .01) in pigs fed CrPic but not in pigs fed CrCl3.6H2O and(or) Pic.(ABSTRACT TRUNCATED AT 250 WORDS)     

Radioimmunoassay for serum thyroxine

A new procedure for radioimmunoassay (RIA) was applied to determine the serum concentration of thyroxine (T4). Mixtures of T4-methylester hydrochloride-bovine serum albumin complex and complete Freund's adjuvant were injected to rabbits to get them immunized. Specific anti-T4 rabbit serum, high in titer, could be obtained 18 months after the start of immunization. RIA for T4 extracted by ethanol from serum was performed by an application of dextran-coated charcoal to separate bound and free 125-i-t4. on the other hand, RIA for T4 performed directly in the serum containing 100 mg/100 ml of 8-anilino-1-naphthalene-sulfonic acid (ANS) gave a similar standard curve for T4 obtained by the ethanol-extraction method. Serum T4 values obtained by the methanol-extraction method were 9.7 +/- 3.3 mug/100 ml for patients with hyperthyroidism and 0.6 +/- 0.3 mug/100 ml for those with hypothyroidism. The corresponding figures obtained by RIA in the serum containing ANS were 11.1 +/- 2.1, 19.1 +/- 3.3 and 0.7 +/- 0.7 mug/100 ml, respectively. The figures positively correlated respectively to the serum T4 values obtained by the competitive protein-binding analysis method (Tetrasrob-125).