Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses. 相似文献
The absorption of crystalline ascorbic acid, ascorbyl palmitate, ascorbyl stearate and a formulation of ascorbic acid was investigated in six mature Thoroughbred horses following oral administration. It was found that ascorbyl palmitate gave both highest plasma concentrations and greatest area under the curve (AUC) for ascorbic acid. Least variation between animals also occured for this preparation. No apparent absorption was seen in some animals given ascorbic acid or ascorbyl stearate. 相似文献
AIM: To examine the relationships between workplace bullying, destructive leadership and team conflict, and physical health, strain, self-reported performance and intentions to quit among veterinarians in New Zealand, and how these relationships could be moderated by psychological capital and perceived organisational support.
METHODS: Data were collected by means of an online survey, distributed to members of the New Zealand Veterinary Association. Participation was voluntary and all responses were anonymous and confidential. Scores for the variables measured were based on responses to questions or statements with responses categorised on a linear scale. A series of regression analyses were used to assess mediation or moderation by intermediate variables on the relationships between predictor variables and dependent variables.
RESULTS: Completed surveys were provided by 197 veterinarians, of which 32 (16.2%) had been bullied at work, i.e. they had experienced two or more negative acts at least weekly over the previous 6 months, and nine (4.6%) had experienced cyber-bullying. Mean scores for workplace bullying were higher for female than male respondents, and for non-managers than managers (p<0.01). Scores for workplace bullying were positively associated with scores for destructive leadership and team conflict, physical health, strain, and intentions to quit (p<0.001). Workplace bullying and team conflict mediated the relationship between destructive leadership and strain, physical health and intentions to quit. Perceived organisational support moderated the effects of workplace bullying on strain and self-reported job performance (p<0.05).
CONCLUSIONS: Relatively high rates of negative behaviour were reported by veterinarians in this study, with 16% of participants meeting an established criterion for having been bullied. The negative effects of destructive leadership on strain, physical health and intentions to quit were mediated by team conflict and workplace bullying. It should be noted that the findings of this study were based on a survey of self-selected participants and the findings may not represent the wider population of New Zealand veterinarians. 相似文献
The mass extinction at the end of the Permian was the most profound in the history of life. Fundamental to understanding its cause is determining the tempo and duration of the extinction. Uranium/lead zircon data from Late Permian and Early Triassic rocks from south China place the Permian-Triassic boundary at 251.4 +/- 0.3 million years ago. Biostratigraphic controls from strata intercalated with ash beds below the boundary indicate that the Changhsingian pulse of the end-Permian extinction, corresponding to the disappearance of about 85 percent of marine species, lasted less than 1 million years. At Meishan, a negative excursion in delta13C at the boundary had a duration of 165,000 years or less, suggesting a catastrophic addition of light carbon. 相似文献
A survey of 73 dairy farms in south-western Victoria was conducted to assess the cost and mean herd incidence of foot lameness for the period from calving to the end of November, 1985, and to identify the herd, management and environmental factors associated with foot lameness. The mean herd size was 125 cows (range 82 to 220). Lameness occurred in 64 (88%) herds, and the mean herd incidence was 7.0% (range 0.0 to 30.9%). The main clinical signs associated with lameness were the presence of overworn and/or bruised soles, or stones lodged in the interdigital cleft. Factors associated with lameness were: property and herd size, age of cow, bail feeding, voluntary entry into the bails, and features of the farm track including its length, the presence of steep slopes, the type of surface material, presence and treatment of broken sections and maintenance including rolling history. The association of these factors with specific clinical signs was examined. The mean cost was estimated to be $42.90 per lame cow due to loss of production, treatment, the culling or death of lame cows, and extra man hours spent managing lame cows. It was concluded that the site, construction, maintenance and use of the farm track were of major importance to the incidence of lameness in herds in this area and recommendations for reducing lameness are made. 相似文献
The distribution and morphology of fibrous astrocytes in the cervical spinal cord of normal horses and horses with chronic compressive myelopathy were demonstrated using immunohistochemical staining for glial fibrillary acidic protein. In the spinal cord from normal horses, astrocytes with stellate cell bodies and short processes were irregularly distributed in grey matter. In the white matter, their cell bodies were small and angular in areas adjacent to grey matter and larger and more stellate-shaped in the subpial area. Astrocyte processes were fine, and evenly distributed in a predominantly radial pattern in transverse sections of cord. Gliosis was marked in the spinal cords of horses with cervical compressive myelopathy. In the grey matter at the level of compression astrocytes were often enlarged and rounded, with short, blunt processes, but the gliosis was generally mild. In the white matter, gliosis was obvious in areas of nerve fibre swelling and degeneration at the level of compression and in areas of ascending and descending Wallerian degeneration. The fine radial pattern of astrocyte fibres was replaced by a dense, irregular arrangement. Gliosis persisted in the cords of chronically affected horses after active nerve fibre degeneration had subsided. The areas of gliosis coincided with the areas of Marchi staining for degenerating myelin and with areas of myelin loss in osmium tetroxide post-fixed tissue. Histological observations were consistent with astrocytes replacing areas of extracellular space that remained after nerve fibre degeneration. it is concluded that astrocytic gliosis is a prominent and persistent alteration of the spinal cord of horses with chronic cervical compressive myelopathy. 相似文献
