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111.
Platelet activating factor (PAF) is known to be a chemoattractant for equine neutrophils in vivo and in vitro. In this study the in vitro migratory response of equine eosinophils and neutrophils to PAF has been examined and compared with that to leukotriene (LT)B4. PAF (10(-8) to 10(-5) M), but not lyso-PAF (10(-6) M), caused dose related migration of both equine eosinophils and neutrophils, maximal responses occurring at 10(-6) M. Responses to PAF were inhibited by the receptor antagonist WEB 2086. LTB4 (10(-8) to 10(-6) M) also induced migration of both cell types, although the maximum effect was observed with a 10-fold lower concentration. Moreover, the maximum response of equine eosinophils to LTB4 was significantly greater than to PAF. It is concluded that LTB4 and PAF, if released in vivo at sites of allergic or inflammatory reactions, could mediate the recruitment of leucocytes to the involved tissue. 相似文献
112.
Progressive ethmoidal haematoma was diagnosed in 12 Thoroughbreds, 1 part- Arab and 1 stock horse. Ages ranged from 3 to 18 years and both males and females were affected. Diagnosis was based on history, clinical signs, endoscopic and radiographic findings, and was confirmed histologically in 10 cases. Eleven (78%) of the lesions were unilateral and 3 (22%) were bilateral. Two horses were euthanased on diagnosis, 4 were treated conservatively. Of the latter, 3 were euthanased 6 to 24 months after diagnosis, due to progression of the lesions, while 1 case resolved completely within 13 months. Eight horses were treated by surgical excision of the lesion. Three died in the post-operative period, 3 were euthanased within 48 months after recurrence of the condition, and 2 had no recurrence within 60 and 72 months, respectively. 相似文献
113.
D L Cunningham 《British poultry science》1988,29(2):265-271
The Cornell (8L:10D:2L:4D) and (Ralston Purina) Biomittent lighting programmes were applied to a commercial strain of White Leghorn laying hens from 20 to 64 weeks of age. 2. The egg production of hens exposed to the Cornell lighting was reduced compared to the Bio-mittent programme. 3. Food consumption was less and efficiency of utilisation significantly improved for the Cornell programme during phase I (20 to 36 weeks) of the study. Significant differences were not observed during phase II (37 to 64 weeks) or for the whole cycle (20 to 64 weeks). 4. Body weights were significantly greater for hens exposed to the Bio-mittent programme during both phases I and II. 5. Egg weights, egg mass and egg weight distributions were not different for hens exposed to the 2 programmes. 6. Food costs and the margin of income over food costs were significantly in favour of the Cornell programme during phase I. However, differences for phase II and the complete cycle were not significant. 7. The Bio-mittent programme offered a computed advantage of 14.4% fewer hours of light usage compared to the Cornell programme. 相似文献
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Recurrent airway obstruction (RAO) and insect bite hypersensitivity (IBH) are allergic conditions that are commonly encountered in the horse. Whilst complete allergen avoidance is an effective management strategy for both diseases, this may not be achievable in all cases and treatment options are therefore required. The inflammatory response is the main therapeutic target for glucocorticoids given to horses with RAO and severe cases of IBH, whilst the bronchodilators used in RAO primarily target airway smooth muscle. Such drugs are effective in most but not all individuals and there may be unwanted adverse effects. This article will review how knowledge of drug action and the pathogenesis of RAO and IBH can be utilised to identify potential targets for novel therapeutic agents that, in the longer term, may be safer and/or more effective in managing the allergic horse. 相似文献
119.
1. A single injection into laying hens of 60 mg metyrapone 28 h after the final ovulation of a sequence induced increases in the plasma concentrations of LH and progesterone, followed by premature ovulation. Injection of metyrapone 8 h after ovulation, however, did not affect plasma concentrations of either LH or progesterone.
2. Injection of laying hens with 60 mg metyrapone on 5 successive days reduced the effectiveness of exogenous ACTH in increasing the plasma concentration of corticosterone and abolished the system of “ open “ and “ closed periods “ for pre‐ovulatory LH release. Thus, pre‐ovulatory LH surges and ovipositions occurred throughout the 24‐h day instead of being restricted to an 8 to 10‐h period of the day.
3. These observations suggest that changes in environmental stimuli such as light act via the adrenal gland in regulating the timing of the “ open period “ for the pre‐ovulatory release of LH in the hen. 相似文献
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