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Summary Retinal Müller glial cells are of vital importance for maintaining a physiological environment within the retina. To this end, they provide highly specialized physiological properties to support neurons in structure, nutrition and metabolism. The purpose of this study was to isolate Müller cells from the equine retina, determine their characteristics and subsequently establish a stable equine Müller cell line (eqMC) that will provide a prerequisite for investigations on their physiological properties. Dissociated retinal cells were obtained from equine retinas by a papain digestion technique followed by trituration and a cell attachment method by which pure Müller cell cultures were achieved. Morphological examination was performed using phase-contrast microscopy, and further characterization of different subcultures was accomplished by immunocytochemistry. Cells of passage 1 showed distinct signals for glutamine synthetase and vimentin, whereas glial fibrillary acidic protein expression was almost absent. Characteristic expression patterns remained unaltered in all subcultures. Furthermore, cultured Müller cells stably expressed the microfilament alpha-smooth muscle actin, the proliferation marker Ki67 and the membrane channels Kir4.1 and aquaporin 4. The present study introduces the eqMC-7 that will facilitate studies investigating the physiological role of Müller cells within the equine retina. [ABSTRACT FROM AUTHOR]

Using ruminally cannulated steers, we investigated how urinary allantoin excretion was related to variations in feed intake and stage of forage maturity. Further, different approaches were compared for predicting ruminal microbial crude protein (MCP) synthesis and its efficiency. Experimental diets were arranged in a replicated 3 × 3 Latin square design (experiment 1) and a 4 × 4 Latin square design (experiment 2). In experiment 1, a mixed diet [forage to concentrate, 68:32 on a dry matter (DM) basis] was fed at three intake levels corresponding to 1, 1.5 and 2 times maintenance energy requirements. In experiment 2, four silage-based diets were fed based on perennial ryegrass ( Lolium perenne L.), which was harvested at four maturity stages. Both experiments demonstrated the influence of diet on microbial growth rate and by this on efficiency of MCP synthesis, although the magnitude of the effects differed between approaches used for estimating MCP. Linear functions satisfactorily characterised the relationship between urinary allantoin excretion ( y) and digestible organic matter (OM) intake ( x, kg/day; experiment 1: y = 7.94 + 17.34 x; R2 = 0.785) or intake of OM effectively degraded in the rumen ( x, kg/day; experiment 2; y = 22.32 + 5.93 x; R2 = 0.695). Urinary excretion of allantoin permitted a semi-quantitative prediction of MCP synthesis: ranking of diets and magnitude of changes in MCP synthesis were reflected. [ABSTRACT FROM AUTHOR]

Fasting dogs do transport vitamin A (VA) in plasma not only as retinol but predominantly as retinyl esters. Contrary to retinol, nothing is known concerning the effects of athletic performance on plasma retinyl ester concentrations. The aim of this study was therefore to examine whether physical stress because of exercise and modification of the oxidative stress by supplementation of α-tocopherol influences the concentrations of retinol and retinyl esters in plasma of sled dogs. The study was carried out on 41 trained adult sled dogs, which were randomly assigned into two groups. One group (19 dogs) was daily substituted with 50 mg dl- α-tocopheryl acetate per kilogram body weight and the control group (22 dogs) was maintained on a basal diet during 3 months prior to exercise. The plasma concentrations of retinol, retinyl esters, α-tocopherol and triglycerides were measured immediately before, directly after and 24 h after exercise. The supplementation of α-tocopheryl acetate had no effect on plasma retinol and retinyl ester concentrations at any measurement time point. However, retinyl ester levels doubled in the non-supplemented group immediately after the race (p < 0.001), whereas in the supplemented group similar high levels were observed not until 24 h post-racing (p < 0.001). The high levels of retinyl esters were paralleled to some extent by an increase in plasma triglyceride concentrations, which were significantly higher 24 h post-racing than immediately before (p < 0.001) and after exercise (p < 0.001) in both groups. The increase in retinyl ester concentrations might be indicative of their mobilization from liver and adipose tissue. Whether plasma retinyl esters can be used as an indicator for the extent of nutrient mobilization during and post-exercise in sled dogs remains to be elucidated. [ABSTRACT FROM AUTHOR]

To measure the immunoglobulin G (IgG) concentration in colostrum, milk and serum samples, a sandwich enzyme-linked immunosorbent assay (ELISA) detection system was developed. The system provided high reproducibility and sensitivity for routine diagnostic purposes. The period of fluctuating serum concentrations of IgG was monitored in new-born foals and their mares for a period of 6 weeks postnatum and postpartum, respectively. All foals received colostrum from their mares. The mean IgG concentration in the precolostral mare serum was approximately 19.0 mg/ml and decreased significantly to 13.8 mg/ml within the first 24 h postpartum. The IgG value fell to a minimum of 11.2 mg/ml by day 21 and increased to 21.6 mg/ml by day 42 postpartum. Within the first 4 h postpartum, mean IgG concentrations of 54.5 mg/ml were measured in the colostrum. A significant decrease to 10.1 mg IgG/ml colostrum was then noted 9–12 h postpartum. The mean IgG concentrations in foal serum increased from 0.3 mg/ml (precolostral value) to 9.6 mg/ml within 5–8 h postnatum. After 13–16 h postnatum, the highest IgG value of 15.7 mg/ml was reached. Over time the mean IgG concentration decreased significantly to 7.9 mg/ml at day 35. At the end of the observation period (day 42 postnatum) the mean IgG concentration once again increased to 11.2 mg/ml serum. In addition, the possible influence of various parameters on IgG concentration were examined. No significant influences could be shown by the breed, mare age, number of pregnancies, days of gestation, month foaled, foal sex, or the different farms. Finally, the cumulative incidence of failure of passive transfer (FPT) defined as IgG levels < 4 mg/ml foal serum, and partial FPT (PFPT) at levels ranging from 4 to 8 mg/ml foal serum was determined. From a total of 70 foals, 10.0% showed FPT and 18.6% showed PFPT. [ABSTRACT FROM AUTHOR]

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Freund's Complete Adjuvant in the Chicken: Efficient Immunostimulation but Severe Local Inflammation To quantify the enhancing activity of Freund's complete adjuvant (FCA), the humoral immune response of hens to the antigen human serum albumin (HSA) injected intramuscularly combined with FCA was measured. Local tissue reaction was examined on macroscopic and microscopic level. Other hens were injected with HSA in physiological sodium-chloride solution and served as controls. The immunization of hens without using FCA resulted in a short-term rise in immunoglobulin G (IgG) antibody titres, while the hens injected with HSA and FCA developed a long-term response (plateau-form of antibody titres). Local tissue reaction after injection of HSA in sodium-chloride solution was a mild and transient form of interstitial myositis. The immunization with HSA combined with FCA regularly resulted in a persisting granulomatous myositis. It is therefore a matter of animal protection to demand restricted use of FCA and to promote adjuvants of comparable efficiency, but better tolerance. Zusammenfassung In der vorliegenden Arbeit wurden die humorale Immunantwort von Hühnern gegenüber dem intramuskulär in Kombination mit Freundschem komplettem Adjuvans (FCA) verabreichten Antigen humanes Serumalbumin (HSA) quantifiziert und lokale Gewebereaktionen auf makroskopischer und lichtmikroskopischer Ebene untersucht. Zum Vergleich wurde HSA in physiologischer Kochsalzlösung appliziert. Die Immunisierung von Hühnern ohne FCA führte zu zeitlich sehr begrenzten IgG-Antikörpertitern. Die Verwendung von FCA bei der Immunisierung mit HSA resultierte in der Ausbildung eines langanhaltenden, hohen Antikörpertiter-Plateaus. Die lokale Gewebereaktion nach Immunisierung mit HSA in physiologischer Kochsalzlösung war durch eine vorübergehende geringgradige interstitielle Myositis gekennzeichnet. Die Immunisierung unter Verwendung von FCA hatte regelmäßig die Entwicklung einer persistierenden granulomatösen Myositis zur Folge. Uinter dem Aspekt des Tierschutzes ist deshalb zu fordern, auf die Verwendung von FCA soweit als möglich zu verzichten und stattdessen besser verträgliche aber vergleichbar effiziente Adjuvantien zu entwickeln und einzusetzen. [ABSTRACT FROM AUTHOR]

The Influence of Rumen Metabolism on Cyclic N-Compounds in the Blood Plasma of Ruminants The purpose of this paper was to study the effect of rumen metabolism on the concentration of certain cyclic N-compounds in blood plasma. The plasma from two groups of lambs in the phase of rumen development during early and late weaning was used. As a second model, samples from steers fed at maintenance and after emptying of the rumen via cannula were used. Plasma samples were obtained from the jugular vein in regular intervals. The HPLC-technique was employed as analytical method. The plasma levels of allantoin and of hippuric acid increased about 2.2-3.7 fold and 2.4-6.4 fold in lambs during rumen development. They decreased to about 43 % and 13 % after emptying the rumen of steers. These metabolites appear to reflect rumen protein synthesis and fibre breakdown and are considered useful estimators of rumen function. Cytidine, uridine, uric acid and hypoxanthine were only influenced in part by rumen metabolism. Plasma pseudouridine was decreased and creatinine was increased in lambs in relation to body mass and remained unaffected in steers. Zusammenfassung Um den Einfluß des Pansenstoffwechsels auf bestimmte zyklische N-Verbindungen im Blutplasma von Wiederkäuern zu klären, wurden Proben aus zwei Untersuchungsreihen gewonnen und mittels HPLC analysiert: erstens von Lämmern vor und nach früher bzw. später Entwöhnung; zweitens von Ochsen mit Pansenkanülen vor und nach Entleerung des Pansens. Die Plasmawerte von Allantoin und Hippursäure erhöhten sich während der Pansenentwicklung 2, 2 bzw. 2, 4 fach (frühentwöhnte Gruppe) und 3, 7 bzw. 6, 4 fach (spätentwöhnte Gruppe). Die Metabolitkonzentration im Plasma von Ochsen nahmen nach Entleerung des Pansens auf rund 43 % (Allantoin) und 13 % (Hippursäure) der Normalwerte ab. Diese Metaboliten können zur Bewertung der Proteinsynthese bzw. der Faserverdauung im Pansen herangezogen werden. Die Konzentrationen von Uridin, Cytidin, Harnsäure und Hypoxanthin im Plasma hängen weniger deutlich vom Pansenstoffwechsel ab und unterliegen auch anderen Einflüssen. Pseudouridin und Kreatinin im Plasma waren unabhängig vom Pansenstoffwechsel. Ihre Konzentrationen fielen (Pseudouridin) bzw. stiegen (Kreatinin) mit der Körpermasse. [ABSTRACT FROM AUTHOR]

On the action of a glucocorticoid on glucose metabolism of pygmy goats 1st Communication: Some metabolites of energy metabolism In order to study mechanisms in ruminants responsible for glucocorticoid-induced hyperglycemia the effects of a single intravenous dose of a glucocorticoid on energy metabolism were investigated by measuring plasma levels of glucose, lactate, free fatty acids (FFA), 3-hydroxybutyrate (3-HOB) and acetoacetate (AcAc). Experiments were performed on four castrated male African pygmy goats at two metabolic states: 'fed' with a single daily meal of hey and 'fasted' with starvation for 3 days. The untreated goats served as their own control. The glucocorticoid application to fed animals resulted in an increase in glucose level (+43%) lasting more than 11 h and an irregular increase of lactate. The concentration of 3-HOB was increased especially before feeding (+64%). In contrast, FFA were decreased (-27%) the second day after glucocorticoid application. In fasted goats the glucocorticoid also caused an increase in glucose level (+ 25%). The effect was smaller than in fed animals. Concentrations of FFA, 3-HOB and AcAc were 10, 20 and 35 % lower than those of untreated goats. With regard to the antiketotic use of glucocorticoids the decrease of plasma levels of FFA and ketone bodies in starving animals is of special importance. Obviously the animals were able to use glucose again as a main energy source instead of FFA. Zusammenfassung Um bei Wiederkäuern Einblick in die für die Glucocorticoid-induzierte Hyperglykämie verant-wortlichen Mechanismen zu gewinnen, wurden die Auswirkungen einer einmaligen Glucocorticoid-Behandlung auf den allgemeinen Energiestoffwechsel anhand von Blutspiegelmessungen der Metabolite Glucose, Lactat, freie Fettsäuren (FFS), 3-Hydroxybutyrat (3-HOB) und Acetacetat (AcAc) untersucht. Als Versuchstiere wurden vier kastrierte Böcke der Rasse 'Afrikanische Zwergziege' zum einen im Stoffwechselzustand 'gefüttert' mit einer einmal täglichen Heu-Fütterung und zum anderen nach 3tägigem Futterentzug im Stoffwechselzustand 'hungernd' entweder unbehandelt oder nach intravenöser Glucocorticoid-Verabreichung untersucht. Die Glucocorticoid-Behandlung verursachte bei den gefütterten Tieren einen plateauartigen Anstieg (43%) des Glucosespiegels und einen unruhigen, insgesamt ansteigenden Verlauf der Lactat-konzentration. Die 3-HOB-Werte waren insbesondere vor der Futteraufnahme um 64% erhöht. Demgegeniiber zeigten die FFS erst am 2. Tag nach der Behandlung einen um 27% erniedrigten Tagesspiegel. Bei hungernden Tieren verursachte die Glucocorticoid-Behandlung ebenfalls einen Anstieg des Glucosespiegels (25%), der allerdings geringer ausfiel als bei gefütterten. Die Konzentration der FFS lag um 10%, die von 3-HOB um 20% und die von AcAc um 35% unter den Werten der unbehandelten Gruppe. Im Hinblick auf den antiketogenen Einsatz von Glucocorticoiden kommt dem Absinken der Plasmaspiegel der FFS und der Ketonkörper bei hungernden Tieren besondere Bedeutung zu. Den Tieren war es mit Einsetzen der Hyperglykämie offensichtlich möglich, ihren Energiebedarf wieder vermehrt über Glucose zu decken und die Verstoffwechslung alternativer Energiesubstrate (FFS) zu reduzieren. [ABSTRACT FROM AUTHOR]

Effects of a Glucocorticoid on Glucose Metabolism in Pygmy Goats 2. Glucose Turnover and Recycling In the present study glucose kinetic parameters like pool size, distribution volume and rates of total entry and irreversible loss were determined in four castrated male African pygmy goats during hyperglycemia induced by an intravenous glucocorticoid injection (0. 25 mg dexamethasone = DXM per kg body weight). Experiments were done at two different metabolic states, 'fed' once daily and 'fasted' after three days of starvation. The use of [U-14C]- together with [2-3H]- or [6-3H]-glucose made it possible to show changes in rates of gluconeogenesis, phosphorylation and specific recycling of glucose-C (e. g. lactate/alanine). During glucocorticoid induced hyperglycemia (+ 45%) in fed animals de novo synthesis of glucose (+5%) and lactate/alanine recycling increased (+4%). Rates of irreversible loss for all applied tracers in fasted animals formed only two thirds of the values of fed animals. During hyperglycemia (+40%) after DXM-injection de novo synthesis of glucose (+8%) and lactate/alanine recycling also increased (+27%). Furthermore the rate of phosphorylation of glucose decreased in fasted pygmy goats. The increase in availability of glucose both in fed and fasted animals is due to an increase in gluconeogenesis. In fasted animals additionally a decrease in the rate of phosphorylation and therefore of the peripheral glucose turnover has to be considered. Zusammenfassung In der vorliegenden Untersuchung wurden Pool, Verteilungsraum, Gesamteintrittsrate (GER) und irreversibler Verlust (IRL) als Parameter des Glucosestoffwechsels an vier kastrierten männlichen Afrikanischen Zwergziegen bei einer durch Glucocorticoid (0,25 mg Dexamethason / kg KGW, intravenös) induzierten Hyperglykämie bestimmt. Die Versuche wurden bei einmal täglich gefütterten Tieren und nach 3tägigem Futterentzug (hungernd) durchgeführt. Der Einsatz von [U-14C]- und [2-3H]- oder [6-3H]-Glucose ermöglichte die zusätzliche Darstellung von Veränderungen bei der Gluconeogenese, der Phosphorylierungsrate und spezifischer Recyclingraten von Glucose (z. B. über Lactat/Alanin). Bei den gefütterten Tieren war wahrend der Glucocorticoid-induzierten Hyperglykämie (+45%) die Neusyntheserate von Glucose um 5% und das Lactat/Alanin-Recycling um 4% erhöht. Die irreversiblen Verluste der hungernden Tiere lagen fur alle venvendeten Glucosemar-kierungen um ein Drittel niedriger als die Vergleichswerte gefiitterter Tiere. Nach DXM-Behandlung stieg wahrend der Hyperglykamie (+40%) auch die Neusynthese von Glucose um 8% und das Lactat/Alanin-Recycling um 27% an. Zusätzlich nahm in diesem Stoffwechselzustand die Phosphorylierungsrate von Glucose um 20% ab. Die bei beiden Stoffwechselzustanden festgestellte Zunahme der Glucoseverfugbarkeit ist auf eine Steigerung der Gluconeogenese zurückzuführen, wobei im Hungerzustand zusätzlich eine Abnahme der Phosphorylierungsrate und damit des peripheren Glucoseumsatzes zu berücksichtigen ist. [ABSTRACT FROM AUTHOR]

Focuses on the absorption and synthesis of immunoglobulins G in newborn calves in Germany. Importance of colostrum for the reduction of newborn mortality; Consideration of the body weight gain of the calves; Suggestion of further investigations on immunoglobulin absorption.

Editorial. Pays tribute to Manfred Kirchgebner who will resign from active duty as chief editor of the 'Journal of Animal Physiology and Animal Nutrition,' and become honorary editor of the journal at the end of December 2002. Career achievements; Dedication to the journal; Commitment to improving the content of the journal.

The time course of serum concentrations of the bovine IgG1 and IgG2 was monitored in 18 newborn colostrum-fed calves from birth to 11 weeks of age. All calves received three 1.5 l meals of a pooled colostrum with IgGl and IgG2 concentrations of 54.9 mg/ml and 4.2 mg/ml during the first 14 h post-natum. The mean IgG concentrations in calf serum increased from 0.15 mg IgG1/ml and 0.06 mg IgG2/ml (precolostral values) to 9.3 mg IgG1/ml and 0.8 mg IgG2/ml 12 h after the third colostrum meal. Thereafter, IgG1 decreased continuously to a minimum level of 4.9 mg/ml (p < 0.05) at day 28 post-natum and increased to 9.0 mg/ml at day 77. Postcolostral mean IgG2 was lowest (0.5 mg/ml) at day 11 and highest (1.2 mg/ml) at day 77. With these postcolostral IgG concentrations the respective body weight-corrected serum IgG pools approximately were calculated. According to that procedure the initially high IgG pool in the serum at day 2 corresponds to 11.3 and 8.7%, respectively, of the ingested colostral IgG1 and IgG2. The time course of these IgG pools in the serum could be characterized by four typical phases. After a rapid increase from 0.45 g to 22.6 g (12 h after the last colostrum meal) in phase I, the total serum IgG decreased to 17.6 g at day 11 post-natum (phase II) and levelled-out until day 28 post-natum at a value of 17.3 g (phase III). In phase IV total serum IgG increased to 49.3 g at the end of the observation period (week 11). Considering these IgG values, which had been standardized by body weight, the endogeneous IgG production seemed to start clearly (at week 1–2 post-natum) before the increase of the IgG concentration in the serum. To measure these IgG1 and IgG2 concentrations in the serum as well as in the colostrum, sandwich ELISA detection systems were developed which specifically quantify these IgG subclasses in cattle. The specific immunoglobulin Y (IgY) could be isolated from the egg yolk of laying hens which have been immunized with bovine IgG1... [ABSTRACT FROM AUTHOR]

Objective: Activation of basophils contributes to memory immune responses and results in exacerbation of collagen-induced arthritis (CIA). We undertook the present study to analyze the production and biologic effects of interleukin-3 (IL-3), a strong activator of basophils, in CIA., Methods: Arthritis was induced by immunization with type II collagen. Mice were treated with blocking monoclonal antibodies against IL-3 or with recombinant IL-3. Clinical scoring, histologic analysis, fluorescence-activated cell sorter analysis, enzyme-linked immunosorbent assay, and cell culturing were performed to assess disease activity and IL-3 production., Results: IL-3 was produced in large quantities by collagen-specific CD4+ T cells in the spleen and was present in the synovial tissue during onset of arthritis, but was down-regulated in paws with severe inflammation. Blockade of IL-3 during the time of arthritis onset resulted in profound improvement of the disease, with reductions in synovial leukocyte and cytokine levels, peripheral blood basophil levels, and anticollagen antibody titers. Blockade of IL-3 during the late phase of arthritis had no beneficial effect. Administration of recombinant IL-3 during onset of arthritis induced a marked exacerbation of the disease, with increased peripheral blood basophil and plasma IL-6 levels and increased titers of anticollagen antibody. In studies of the regulation of IL-3 expression in CD4+ T cells, IL-6 and IL-4 suppressed the release of IL-3 by activated CD4+ T cells, whereas lipopolysaccharide and CpG DNA up-regulated IL-3 secretion in activated CD4+ T cells by acting on costimulatory cells., Conclusion: Taken together, the present results demonstrate for the first time that IL-3 has an important role in the early phase of CIA.

Objective: The chemokine receptor CCR2 is highly expressed on monocytes and considered a promising target for treatment of rheumatoid arthritis. However, blockade of CCR2 with a monoclonal antibody (mAb) during progression of collagen-induced arthritis results in a massive aggravation of the disease. In this study we investigated why CCR2 antibodies have proinflammatory effects, how these effects can be avoided, and whether CCR2+ monocytes are useful targets in the treatment of arthritis., Methods: Arthritis was induced in DBA/1 mice by immunization with type II collagen. Mice were treated with mAb against CCR2 (MC-21), IgE, or isotype control antibodies at various time points. Activation of basophils and depletion of monocyte subsets were determined by fluorescence-activated cell sorter analysis and enzyme-linked immunosorbent assay., Results: Crosslinkage of CCR2 activated basophils to release interleukin-6 (IL-6) and IL-4. In vivo, IL-6 release occurred only after exposure to high doses of MC-21, whereas application of low doses of the mAb circumvented the release of IL-6. Regardless of the dose level used, the antibody MC-21 efficiently depleted Gr-1+,CCR2+ monocytes from the synovial tissue, peripheral blood, and spleen of DBA/1 mice. Activation of basophils with high doses of MC-21 or with antibodies against IgE resulted in a marked aggravation of collagen-induced arthritis and an increased release of IL-6. In contrast, low-dose treatment with MC-21 in this therapeutic setting had no effect on IL-6 and led to marked improvement of arthritis., Conclusion: These results show that depletion of CCR2+ monocytes may prove to be a therapeutic option in inflammatory arthritis, as long as the dose-dependent proinflammatory effects of CCR2 mAb are taken into account.

Objective: To study the role of the chemokine receptors CCR5 and CCR2 in patients with arthritis., Methods: CCR5 expression on peripheral blood leukocytes was compared with the expression on leukocytes isolated from the synovial fluid of 20 patients with different rheumatic joint diseases. Three additional samples were studied for CCR2 expression. The expression of chemokine receptors on blood and synovial fluid leukocytes was determined by 3-color flow cytometry analysis. To test CCR5 receptor down-modulation from the cell surface, leukocytes were incubated in vitro with a RANTES (regulated on activation, normal T cell expressed and secreted) derivative, aminooxypentane (AOP)-RANTES. Patients were genotyped for the delta32 CCR5 deletion by polymerase chain reaction., Results: A high percentage of CCR5-expressing CD4+ and CD8+ T cells (74% and 81%, respectively), monocytes (51%), and natural killer cells (35%) was found in the synovial fluid of all patients, whereas in the peripheral blood, only a small percentage of these cells expressed CCR5 (13%, 32%, 7.8%, and 4%, respectively). Infiltration of CCR5-positive leukocytes was not reduced in CCR5-heterozygous patients. A similar, but less pronounced, distribution was observed for CCR2-positive T cells. In vitro, CCR5 was completely down-modulated on synovial fluid leukocytes by AOP-RANTES., Conclusion: The predominance of CCR5-positive mononuclear cells in the synovial effusions of patients with arthritis suggests an important role for CCR5 in the process of joint inflammation, and identifies CCR5 as a possible new target for therapeutic intervention.