Intradermal testing of horses with chronic obstructive pulmonary disease and recurrent urticaria.

Six horses with chronic obstructive pulmonary disease (COPD) and 8 horses with recurrent urticaria were skin tested with 67 extracts from 58 allergens, including pollens, epidermals, cultivated farm plants, dusts, molds, and insects. Reactions were evaluated 3 times over a 24-hour period immediately after the injections. Results were compared with those obtained from 11 clinically normal horses. All horses had positive skin test reactions. Significant differences was evident between horses with COPD and clinically normal horses for only 3.0% of the possible extract reactions, and between horses with urticaria and clinically normal horses for only 4.5% of the possible extract reactions. Horses with COPD or urticaria had greater total percentage of allergen extract reactions than did clinically normal horses. Positive reactions were observed at all 3 evaluation periods, and late-onset reactions were not always preceded by positive reaction at earlier periods. All horses with COPD or urticaria had at least 1 skin test reaction that exceeded the mean +/- 2 SD, as calculated for each of the 67 extracts for the group of clinically normal horses.     

Radiographic changes in the lungs of horses with exercise-induced epistaxis

This paper describes the distinctive radiographic changes detected in the dorso-caudal lungfields of four racing thoroughbreds recently affected by exercise-induced epistaxis. A diffuse but localized increase in density was seen in all four cases, which demonstrated a variation from a predominantly alveolar density to an interstitial pattern and finally to increased bronchial markings. Evolution of the radiographic pattern of the pulmonary densities appeared to be related to the time that had elapsed since the bleeding incident. The implications of the changing pattern and site of the densities are discussed.     

First evidence of bluetongue virus in Kazakhstan

We report the results of the first serological survey for bluetongue virus in Kazakhstan. We analysed blood samples collected from 958 livestock and 513 wild saiga antelopes over a large area of the country, and found 23.2% seroprevalence in livestock and 0% in saigas. Seroprevalence in livestock did not vary by species, but increased significantly with age. There was no evidence for variation in seroprevalence at the regional level, but there was significant clustering at the farm level. Bluetongue has never before been reported in Kazakhstan, yet our results suggest that it may be endemic. We found seropositive animals at the furthest known northern limits of the bluetongue virus in this region of the world. Recorded vectors are not known to be present in Kazakhstan, so a novel vector is likely to be operating. The lack of evidence for bluetongue virus in saigas is unexpected and suggests a need for further investigation.     

Concentrations of substance P and prostaglandin E2 in synovial fluid of normal and abnormal joints of horses

OBJECTIVE: To correlate substance P content of synovial fluid with prostaglandin E2 content, radiographic evidence of joint abnormality, and anatomic location of the joint for normal and osteoarthritic joints of horses. SAMPLE POPULATION: Synovial fluid from 46 normal joints in 21 horses and 16 osteoarthritic joints in 10 horses. PROCEDURE: Normal and osteoarthritic joints were identified by clinical and radiographic examination, by response to nerve blocks, during scintigraphy or surgery, or by clinicopathologic evaluation. Substance P and prostaglandin E2 contents of synovial fluid were determined by radioimmunoassay. Radio-graphs of joints were assigned a numeric score reflecting severity of lesions. Joints were assigned a numeric score reflecting anatomic location. RESULTS: Median concentrations of substance P and prostaglandin E2 were significantly increased in osteoarthritic joints, compared with normal joints. A significant correlation was found between concentrations of substance P and prostaglandin E2 in synovial fluid, but a correlation was not detected between substance P concentration in synovial fluid and anatomic location of the joint or between radiographic scores of osteoarthritic joints and concentrations of substance P or prostaglandin E2. CONCLUSIONS AND CLINICAL RELEVANCE: A correlation existed between concentrations of substance P and prostaglandin E2 in synovial fluid obtained from normal and osteoarthritic joints. However, content of substance P in synovial fluid cannot be predicted by the radiographic appearance of the joint or its anatomic location. Substance P and prostaglandin E2 may share an important and related role in the etiopathogenesis of osteoarthritis, lending credence to the importance of neurogenic inflammation in horses.     

Requirement for DARPP-32 in progesterone-facilitated sexual receptivity in female rats and mice

DARPP-32, a dopamine- and adenosine 3',5'-monophosphate (cAMP)-regulated phosphoprotein (32 kilodaltons in size), is an obligate intermediate in progesterone (P)-facilitated sexual receptivity in female rats and mice. The facilitative effect of P on sexual receptivity in female rats was blocked by antisense oligonucleotides to DARPP-32. Homozygous mice carrying a null mutation for the DARPP-32 gene exhibited minimal levels of P-facilitated sexual receptivity when compared to their wild-type littermates. P significantly increased hypothalamic cAMP levels and cAMP-dependent protein kinase activity. These increases were not inhibited by a D1 subclass dopamine receptor antagonist. P also enhanced phosphorylation of DARPP-32 on threonine 34 in the hypothalamus of mice. DARPP-32 activation is thus an obligatory step in progestin receptor regulation of sexual receptivity in rats and mice.     

Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. I. Clinical profile of horses

Detailed physical and clinical examinations were performed on 26 Thoroughbred racehorses which were used subsequently in a series of studies to investigate the contribution of the pulmonary and bronchial arterial circulations to the pathophysiology of exercise-induced pulmonary haemorrhage (EIPH). Twenty-five of the horses had been retired from race training in Hong Kong during the 1984-85 season, all but four raced that season; one horse had been retired the previous season. The average number of races for the group that season was 4.1 +/- 2 with an average distance of 1502 +/- 216 metres, mean racing speed 15.5 +/- 0.5 metres/sec. Time from last race to necropsy was 177 +/- 155 days, range 12 to 572 days. All but one horse had a known history of either EIPH or epistaxis. Time from last recorded incident of expistaxis (17 horses) to necropsy was 156 +/- 141 days, range 12 to 513 days, with a longer interval since last recorded endoscopic observation of EIPH. Focal abnormal lung sounds were detected in the dorsocaudal lungfields on auscultation during rebreathing in three horses and six had tracheobronchial cytology consistent with previous episodes of pulmonary haemorrhage (haemosiderophages). No other characteristics which might have allowed separation of this group of horses from other Thoroughbred horses recently in race training were identified.     

Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. VI. Radiological/pathological correlations

This study was initiated to determine if the extent and intensity of lung lesions associated with exercise-induced pulmonary haemorrhage (EIPH) in horses could be predicted from thoracic radiographs. Sets of thoracic radiographs from 24 horses with varied histories of EIPH were subjectively coded for radiographic quality, and perceived extent and intensity of diffuse interstitial opacity by three radiologists who had no knowledge of the corresponding autopsy results. Codes assigned from radiographs for the chosen parameters were compared with coded estimates of lung surface staining assigned at post mortem and volume measurements of haemosiderin deposits and bronchial arterial neovascularisation recorded from lung slices in separate studies. The non-parametric Spearman rank correlation test was used to test for statistical significance. All radiographically coded estimates of lesion severity were positively correlated with post mortem measurements of actual lesion involvement, but only the correlation between coded estimates of lesion opacity versus haemosiderin deposits and bronchial artery neovascularisation were statistically significant (P less than 0.05). Correlations between radiographic codes for lesion extent versus haemosiderin deposits and neovascularisation were just beyond the level of significance (P greater than 0.05 less than 0.1). These findings indicate that there are graded, radiographically discernible increases in interstitial opacity related to actual lesion severity. However, under the conditions of the study, accurate prediction of lung pathology in individual cases based on radiographic criteria was precluded by the wide variance of the coded values. The authors believe that with good radiographic technique and careful criteria selection, satisfactory prediction of lesion severity in EIPH cases could be achieved.     

Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. VIII. Conclusions and implications

This paper reviews a series of clinical, post mortem and imaging studies on exercise-induced pulmonary haemorrhage (EIPH) performed on 26 Thoroughbred racehorses. Post mortem techniques included routine gross, subgross and histological examination; coloured latex perfusions of pulmonary and bronchial circulations; and microradiography and computerised tomography scans of lungs with contrast injected vasculature. The major lesions were multiple, separate and coalescing foci of moderately proliferative small airway disease accompanied by intense neovascularisation of the bronchial circulation. As a result of bronchial artery angiogenesis, the systemic circulation dominated the vascular supply of the air exchange structures in affected areas, producing an apparent left to right shunt. Extensive areas of sequestered haemosiderophages indicated previous haemorrhage from vessels apparently supplied by the bronchial arteries. Diffuse and focal parenchymal destruction and connective tissue reactions in affected areas were considered to be secondary to localised haemorrhage and macrophage-induced damage. The aetiology of EIPH was not determined, but the multifocal, small airway-centred lesions indicated that low grade bronchiolitis, possibly of viral origin, was a factor. Gravitational effects also appear to contribute to dorsal distribution of the lesions. The mild focal and subclinical lesions confined to secondary lobules are thought to evolve into the serious lung pathology observed in EIPH cases through the effects of localised hypoxia induced by maximal exercise and partial airway obstruction. Once initiated, a vicious cycle of increasing inflammatory damage and further local bleeding is set in motion.