非典型猪繁殖和呼吸综合症的回顾

研究表明,猪繁殖和呼吸综合症病毒是造成近10年来美国所谓非典型猪繁殖和呼吸综合症流行的原因。美国的养猪业尽管取得了重大进展,但仍然容易受到各种疾病的侵害,因而需要开发出能快速鉴别新感染的手段。　　现在我们称之为猪繁殖和呼吸综合症的复杂的临床症候群,首次在1989年报告于北美。自那时以来,大量调查研究得出结论认为猪繁殖和呼吸综合症病毒是这一灾难性疾病的病原因子。九十年代早期展现在美国猪兽医面前的猪繁殖和呼吸综合症临床症状是:妊娠后期广泛性繁殖失败、妊娠母猪或公猪临床症状轻微或没有其它临床症状,以及幼猪出现呼吸…     

Chicken leptin: properties and actions

Chicken leptin cDNA shows a high homology to mammalian homologous, with an expression localized in the liver and adipose tissue. It is noteworthy, that the hepatic expression is most likely associated with the primary role that this organ plays in lipogenic activity in avian species. As in mammals, chicken leptin expression is regulated by hormonal and nutritional status. This regulation is tissue-specific and with a high sensitivity in the liver compared to adipose tissue. The blood leptin levels are regulated by the nutritional state with high levels in the fed state compared to the fasted state. The recombinant chicken leptin markedly inhibits food intake as reported in mammals, suggesting the presence of an hypothalamic leptin receptor. The chicken leptin receptor has been identified and all functional motifs are highly conserved compared to mammalian homologous. Chicken leptin receptor is expressed in the hypothalamus but also in other tissues such as pancreas, where leptin inhibits insulin secretion and thus may have a key role in regulating nutrient utilization in this species.     

Enhanced cutaneous hypersensitivity reactions are associated with ovine high and low cortisol responsiveness to acute endotoxin challenge

Inbred rodent studies have demonstrated that cutaneous hypersensitivity reactions are exacerbated in stress-susceptible, and attenuated in stress-resistant strains of mice. This physiological response was, in part, mediated by activation of the hypothalamic-pituitary-adrenal axis during the acute restraint stress. A study was conducted to examine whether or not cutaneous hypersensitivity reactions are also associated with variable cortisol responsiveness to inflammatory stress in an outbred ovine population. High (H), medium (M), and low (L) cortisol responsive sheep were identified from a population of 110 females based on their estimated breeding values for cortisol concentration measured 4 h post-systemic challenge with Escherichia coli endotoxin (400 ng kg(-1)). Cutaneous hypersensitivity reactions to phytohaemagglutinin (PHA), 1-chloro-2, 4-dinitrobenzene (DNCB), and Candida albicans cellular antigen (CAA) were measured in these variable cortisol-responding sheep, in addition to serum interleukin (IL)-6, interferon (IFN)-gamma, and ovalbumin (OVA)-specific IgG concentrations. When compared to the M cortisol responders, both H and L cortisol responders had significantly greater cutaneous swelling during the elicitation phase in response to DNCB (P < 0.05) and CAA (P < 0.05); a similar but not significant trend was observed during the PHA challenge. The primary, but not the secondary, IgG response to OVA was significantly lower in the H and L cortisol responders when compared to the M cortisol responders. Differences in serum IL-6 or IFN-gamma concentration were not observed across variable cortisol-responsive groups. Together, these results demonstrate that cutaneous hypersensitivity reactions are enhanced in outbred H and L cortisol-responding sheep, independent of systemic modulation by IL-6 and IFN-gamma.     

Evaluation of an arthroscopic approach for transection of the equine collateral sesamoidean ligament

Objective: To evaluate: (1) an arthroscopic technique for transection of the collateral sesamoidean ligament (CSL); and (2) the healing response using magnetic resonance (MR) and microscopic examination. Study Design: Experimental study. Animals: Adult horses (n=6). Methods: Six sound horses with normal front foot radiographic and MR examinations were used. Lameness examination was performed before surgery and monthly for 12 months. Front foot radiography was performed at 180 and 360 days after surgery. Front foot MR was performed before, and at 7, 90, 180, and 360 days after surgery. Arthroscopic CSL desmotomy was performed on 1 forelimb. Gross and microscopic examination was performed on the CSL from both forelimbs at 360 days after surgery. Lameness scores were compared over time using the nonparametric Friedman's test for paired groups. CSL measurements were compared using paired t‐tests with a 2‐tailed significance level of P<.05. Results: Radiographs remained normal throughout study period. Surgery resulted in lameness on the operated limb for up to 2 months, after which all horses returned to soundness. CSL transection was confirmed during arthroscopy and with MR examination 7 days after surgery. Gross and microscopic evaluation confirmed ligament healing. Conclusions: CSL desmotomy resulted in short‐term lameness after surgery followed by healing of the CSL confirmed by gross and microscopic analysis.     

Emesis in dogs: a review

Emesis is a common presenting sign in small animal practice. It requires a rational approach to management that is based upon a sound understanding of pathophysiology combined with logical decision making. This review, which assesses the weight of available evidence, outlines the physiology of the vomiting reflex, causes of emesis, the consequences of emesis and the approach to clinical management of the vomiting dog. The applicability of diagnostic testing modalities and the merit of traditional approaches to management, such as dietary changes, are discussed. The role and usefulness of both traditional and novel anti-emetic drugs is examined, including in specific circumstances such as following cytotoxic drug treatment. The review also examines areas in which common clinical practice is not necessarily supported by objective evidence and, as such, highlights questions worthy of further clinical research.     

Sortase anchored proteins of Streptococcus uberis play major roles in the pathogenesis of bovine mastitis in dairy cattle

Streptococcus uberis, strain 0140J, contains a single copy sortase A (srtA), encoding a transamidase capable of covalently anchoring specific proteins to peptidoglycan. Unlike the wild-type, an isogenic mutant carrying an inactivating ISS1 insertion within srtA was only able to infect the bovine mammary gland in a transient fashion. For the first 24 h post challenge, the srtA mutant colonised at a similar rate and number to the wild type strain, but unlike the wild type did not subsequently colonise in higher numbers. Similar levels of host cell infiltration were detected in response to infection with both strains, but only in those mammary quarters infected with the wild type strain were clinical signs of disease evident. Mutants that failed to express individual sortase substrate proteins (sub0135, sub0145, sub0207, sub0241, sub0826, sub0888, sub1095, sub1154, sub1370, and sub1730) were isolated and their virulence determined in the same challenge model. This revealed that mutants lacking sub0145, sub1095 and sub1154 were attenuated in cattle. These data demonstrate that a number of sortase anchored proteins each play a distinct, non-redundant and important role in pathogenesis of S. uberis infection within the lactating bovine mammary gland.     

Mannan-binding lectin (MBL) in two chicken breeds and the correlation with experimental Pasteurella multocida infection

The present study is the first demonstration of an association of the genetic serum Mannan-binding lectin (MBL) concentration with bacterial infections in chickens. The genetic serum MBL concentration was determined in two chicken breeds, and the association with the specific Pasteurella multocida humoral immune response during an experimental infection was examined. Furthermore, we examined the association of the genetic serum MBL concentration with systemic infection. The chickens with systemic infection had a statistically significant lower mean serum MBL concentration than the rest of the chickens, suggesting that MBL plays an important role against P. multocida. A statistically significant negative correlation was found between the specific antibody response and the genetic serum MBL concentration for both breeds. This indicates that MBL in chickens is capable of acting as the first line of defence against P. multocida by diminishing the infection before the adaptive immune response takes over.