CXCL8((3-73))K11R/G31P antagonizes the neutrophil chemoattractants present in pasteurellosis and mastitis lesions and abrogates neutrophil influx into intradermal endotoxin challenge sites in vivo

Toxic products such as reactive oxygen intermediates released by activated polymorphonuclear neutrophil (PMN) have an important role in the pathophysiology of diseases associated with the deposition of immune complexes (IC) in tissues. IC-induced activation of PMN requires adhesion mediated by integrin adhesion receptors. Of the integrins expressed on PMN, the beta(2) family has been found to be of particular importance for activation of PMN by IC. beta(2) Integrin ligand binding must be activated to enable adhesion to IC. Both activating and inhibitory signals regulate beta(2) integrin ligand avidity and adhesion. The second messenger cyclic adenosine monophosphate (cAMP) has been demonstrated to inhibit the activation of PMN in response to a variety of stimuli. The purpose of this study is to test the hypothesis that cAMP-dependent signals inhibit beta(2) integrin-dependent adhesion of equine PMN to immobilized IC and subsequent adhesion-dependent activation of respiratory burst activity. Treatment of equine PMN with beta(2) adrenergic agonists isoproterenol or clenbuterol, which trigger an increase in intracellular cAMP concentration, inhibited adhesion of equine PMN to IC in a dose dependent manner. Similarly, inhibition of cAMP hydrolysis by the non-specific phosphodiesterase (PDE) inhibitor pentoxifylline and the PDE 4-specific inhibitor rolipram inhibited adhesion of equine PMN to IC. Elevation of intracellular cAMP levels with pentoxifylline, clenbuterol and rolipram also inhibited IC-induced activation of respiratory burst activity in equine PMN. Importantly, co-treatment of equine PMN with rolipram and either beta(2) adrenergic agonist synergistically inhibited both the adhesion of equine PMN to IC as well as the subsequent respiratory burst activity.     

Ultraviolet radiation and laying pullets

1. Responses to ultraviolet (UV) radiation were studied in two trials. In one trial, sexually mature pullets, that had been maintained on an 8L:16D regimen from 2 d of age, were exposed sequentially, for periods of 9 to 12 d, to a further 8 h of very dim visible light (VDV), to 8 h of UV radiation and, finally, to an extra 8 h of normal light (conventional 16L:8D). Individual ovipositions were recorded during the last 48 h of each treatment. In the second trial, sexually mature pullets which had been allowed to 'free-run' for 14 d under continuous normal illumination (LL), were given, in addition to the normal light, a 12-h period of UV radiation commencing at midday or midnight for a further 15 d. During the final 48 h oviposition times were recorded and 4 food intakes for each 12-h period were determined. 2. In trial 1, mean oviposition time under VDV and UV supplementation was not significantly different from that under the 8L:16D regimen. Transfer to a 16L:8D regimen altered mean time of oviposition by about 4 h. In trial 2, eggs continued to be laid almost at random in all groups. 3. Food intake was suppressed during the 12-h period of UV supplementation compared with that when the birds were not receiving UV. 4. It is concluded that the addition of 8 h of UV radiation (at the intensity used in these studies) to 8 h of normal light does not cause a phase shift in the timing of the 'open-period' for pre-ovulatory luteinising hormone release which determines the time of oviposition. Furthermore, the insertion of 12-h periods of UV into continuous illumination does not entrain egg laying. 5. The suppressing effect of UV on food intake but lack of influence on the timing of the ovulatory cycle suggests that UV (at the intensity used in this study) acts principally at the retinal level and, as a result, stimulates only behavioural responses in laying birds.     

Yield Effects of Barley yellow dwarf virus in Soft Red Winter Wheat

ABSTRACT Three cultivars of soft red winter wheat were evaluated to determine the relationship between the incidence and time of infection by Barley yellow dwarf virus (BYDV) and yield. Wheat was planted in 1995, 1996, and 1997 in a split-plot design with six replicates at sites in Indiana and Illinois. Yield plots were infested with different amounts of viruliferous aphids, and the incidence of BYDV in each plot was measured. In a 2-year study in Illinois with cv. Clark and the PAV-IL isolate of BYDV, yields were assessed following aphid infestation in fall, early spring, and late spring. Early spring infections resulted in larger yield reductions than late spring infections in both years and larger than fall infections in one year. Regression analyses to relate incidence of infection and yield with data from fall and early spring infections provided R(2) values of 0.89 and 0.51 for the 1996 to 1997 and 1997 to 1998 seasons, respectively. An additional study at the same site in the 1996 to 1997 season compared the yield responses of cvs. Clark, Y88-3e, and PT8935b. Increases in the incidence of BYDV correlated with decreases in yield, with R(2) values of 0.80, 0.78, and 0.90 for the three cultivars, respectively. Estimated yield losses in both studies and all cultivars ranged from 27 to 45 kg/ha or 0.34 to 0.55% for each percent increase in virus infection. In a third study over a 2-year period in Indiana with the same three wheat genot ypes and a second BYDV isolate (PAV-P), BYDV treatments resulted in significant reductions in yield, but yield loss and the incidence of BYDV were not linearly correlated. Given the differences in yield reductions caused by the two BYDV isolates, PAV-P may be an attenuated strain of BYDV and may cross-protect plants from naturally occurring strains of the virus.     

Farmers' attitudes towards techniques for improving oestrus detection in dairy herds in South West England

Unidentified heats contribute to declining fertility rates in English dairy herds. Several techniques have been advocated to improve heat detection rates. Despite demonstrable technical efficacy and cost-effectiveness, uptake is low. A study in South West England used the Theory of Reasoned Action (TORA) to explore dairy farmers' attitudes and beliefs towards heat detection techniques. Few farmers were convinced that following prescribed observation times, milk progesterone testing and using pedometers would fit their system or improve on their current heat detection practices. Perceived difficulty of using a technique was not a constraint on adoption. Without promotion that addresses identified barriers and drivers to adoption, little change in current practice can be expected.     

Stabilization of Sacroiliac Luxation in 40 Cats Using Screws Inserted in Lag Fashion

Objective: To (1) identify prognostic indicators for stability after stabilization of sacroiliac luxation with screws inserted in lag fashion and (2) report dorsoventral dimensions of the sacrum in cats. Study Design: Multicenter retrospective study. Sample Population: Cats (n=40) with sacroiliac luxation. Methods: Case records and radiographs of cats presented at the Queen's Veterinary School Hospital Cambridge and the Royal Veterinary College Hatfield for screw fixation of sacroiliac luxation were reviewed. Dorsoventral dimensions of 15 feline cadaveric sacral bodies were measured to identify the appropriate implant size for use in fixation with screws inserted in lag fashion. Results: Of 40 cats, 13 had left, 14 right, and 13 bilateral sacroiliac luxations. Of 48 screws analyzed, 42 (87.5%) were placed within the sacral body or exited ventrally and 6 (12.5%) were considered malpositioned. Screw purchase within the sacrum was statistically different between unstable and stable repairs (P=.001). Using confidence intervals for screw length within the sacrum and effect on stability, the lowest screw depth that contained 95% of the screws that did not loosen was ∼60% of the sacral width. Mean dorsoventral sacral dimension at its narrowest point was 5.9±1.14 mm. There was no significant difference in the incidence of implant loosening between those luxations that were 100% reduced and those that were <100% reduced (P=.7837). Conclusions: Screw purchase within the feline sacrum of at least 60% of the sacral width significantly reduces the risk of loosening. Clinical Relevance: Screw placement to a depth of 60% of the width of the feline sacrum is recommended.     

Measuring the benefits of disease control: Relationship between herd structure,productivity and health

Summary The influence of calving percentage and mortality levels on heard structures is studied. Standard herd structures with set levels of mortality are calculated for comparison with field data. Herd structures from field surveys in Zambia are studied in order to determine how these can be used to gain more information about herd input and output dynamics. Methods of calculating off-take and the problems relating to making such calculations are discussed.

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Resumen Se estudió la influencia de los niveles de nacimientos y mortalidad en la estructura del hato. Se calcularon estructuras de hatos estandar, con niveles preconcebidos de mortalidad, para compararlos con datos de campo. Se estudiaron las estructuras de hatos en Zambia datos adquiridos en el campo, para determinar cómo éstos pueden utilizarse para obtener mayor información acerca de la dinámica costo-beneficio. Se discuten los métodos para calcular las ganancias y los problemas relacionados con estos cálculos.

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Résumé L'influence du niveau des intrants et des extrants (taux de vêlage et mortalité) sur la structure des troupeaux est étudiée. Des compositions standards avec des taux de mortalité pré-établis sont calculées pour permettre la comparaison avec les données recueillies sur le terrain. A partir d'enquêtes conduites en Zambie, la structure des troupeaux est étudiée en vue de déterminer comment ces résultats peuvent être utilisés pour accro?tre les données relatives à la dynamique des ressources et des emplois pour un troupeau donné. Les méthodes de calcul du taux d'exploitation et les problèmes relatifs à l'élaboration de ces calculs sont discutés.

     

Severe Neutropenia Associated With Griseofulvin Therapy in Cats With Feline Immunodeficiency Virus Infection

Griseofulvin administration was associated with the development of absolute neutropenia in six of seven (86%) cats with feline immunodeficiency virus (FIV) infection. The neutropenia was severe (less than 400 neutrophils/microliter) in four of the six affected cats, and one cat died from sepsis. Neutrophil counts returned to baseline values within 15 days after drug withdrawal in all surviving cats. No symptoms or hematologic abnormalities were observed in four normal (FIV-seronegative) cats treated with the same lot of griseofulvin at equivalent doses. Neutropenia recurred in two of two FIV-seropositive cats upon griseofulvin rechallenge. Cats with FIV infections appear to be at increased risk for griseofulvin-associated neutropenia. This phenomenon may be analogous to the increased frequency of antibiotic-induced neutropenias observed in humans infected with the human immunodeficiency virus.