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61.
Carlos E Hernandez Tomas Thierfelder Kerstin Svennersten-Sjaunja Charlotte Berg Agustin Orihuela Lena Lidfors 《Acta veterinaria Scandinavica》2014,56(1)
Background
Measurement of salivary cortisol has been used extensively as a non-invasive alternative to blood sampling to assess adrenal activity in ruminants. However, there is evidence suggesting a considerable delay in the transfer of cortisol from plasma into saliva. Previous studies in cattle have used long sampling intervals making it difficult to characterise the relationship between plasma and salivary cortisol (PLCort and SACort, respectively) concentrations at different time points and determine whether or not such a time lag exist in large ruminants. Therefore, the objective of this study was to characterise the relationship between plasma and salivary cortisol and determine if there is a significant time lag between reaching peak cortisol concentrations in plasma and saliva across a 4.25 h time-period, using short sampling intervals of 10–15 min, following social separation in dairy cattle.Five cows were separated from their calves at 4 days after calving, and six calves were separated from a group of four peers at 8 weeks of age. Following separation, the animals were moved to an unfamiliar surrounding where they could not see their calves or pen mates. The animals were catheterised with indwelling jugular catheters 1 day before sampling. Blood and saliva samples were obtained simultaneously before and after separation.Results
In response to the stressors, PLCort and SACort increased reaching peak concentrations 10 and 20 min after separation, respectively. This suggested a 10 min time lag between peak cortisol concentrations in plasma and saliva, which was further confirmed with a time-series analysis. Considering the 10 min time lag, SACort was strongly correlated with PLCort (P < 0.0001).Conclusions
Salivary cortisol correlates well with plasma cortisol and is a good indicator of the time-dependent variations in cortisol concentrations in plasma following acute stress. However, there is a time lag to reach peak cortisol concentrations in saliva compared to those in plasma, which should be considered when saliva samples are used as the only measure of hypothalamic-pituitary-adrenal axis response to stress in cattle. 相似文献62.
K. Sjstrand G. Wess I. Ljungvall J. Hggstrm A‐C. Merveille M. Wiberg V. Gouni J. Lundgren Willesen S. Hans A‐S. Lequarr L. Mejer Srensen J. Wolf L. Tiret M. Kierczak S. Forsberg K. McEntee G. Battaille E. Seppl K. Lindblad‐Toh M. Georges Hannes Lohi V. Chetboul M. Fredholm K. Hglund 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2014,28(2):451-457
Background
Measurement of plasma concentration of natriuretic peptides (NPs) is suggested to be of value in diagnosis of cardiac disease in dogs, but many factors other than cardiac status may influence their concentrations. Dog breed potentially is 1 such factor.Objective
To investigate breed variation in plasma concentrations of pro‐atrial natriuretic peptide 31‐67 (proANP 31‐67) and N‐terminal B‐type natriuretic peptide (NT‐proBNP) in healthy dogs.Animals
535 healthy, privately owned dogs of 9 breeds were examined at 5 centers as part of the European Union (EU) LUPA project.Methods
Absence of cardiovascular disease or other clinically relevant organ‐related or systemic disease was ensured by thorough clinical investigation. Plasma concentrations of proANP 31‐67 and NT‐proBNP were measured by commercially available ELISA assays.Results
Overall significant breed differences were found in proANP 31‐67 (P < .0001) and NT‐proBNP (P < .0001) concentrations. Pair‐wise comparisons between breeds differed in approximately 50% of comparisons for proANP 31‐67 as well as NT‐proBNP concentrations, both when including all centers and within each center. Interquartile range was large for many breeds, especially for NT‐proBNP. Among included breeds, Labrador Retrievers and Newfoundlands had highest median NT‐proBNP concentrations with concentrations 3 times as high as those of Dachshunds. German Shepherds and Cavalier King Charles Spaniels had the highest median proANP 31‐67 concentrations, twice the median concentration in Doberman Pinschers.Conclusions and Clinical Importance
Considerable interbreed variation in plasma NP concentrations was found in healthy dogs. Intrabreed variation was large in several breeds, especially for NT‐proBNP. Additional studies are needed to establish breed‐specific reference ranges. 相似文献63.
以水体甲基汞不同浓度(μg/L)分别染毒鲤鱼24小时和1周。实验结果表明:在浓度高于50μg/L染毒24小时和浓度20μg/L染毒1周时,多数染毒鱼的血浆K+和Mg2+浓度增高,Na+和Cl-浓度下降,PO3-4值变化不明显。血浆Ca2+浓度仅在200μg/L染毒24小时和高于40μg/L染毒1周时,染毒鱼的血浆Ca2+出现极显著下降。甲基汞量高于100μg/L染毒24小时和80μg/L染毒1周,染毒鱼的血浆渗透压呈明显下降趋势。鳃线粒体Na+-K+-ATPase活性仅在染毒24小时浓度为25μg/L和50μg/L剂量时受到抑制。甲基汞还引起了血糖含量的明显增高。 相似文献
64.
A.G. Becker J.F. Gonçalves L.O. Garcia E.R. Behr F.J.K. Mallmann D.L. Graça B. Baldisserotto 《Fish physiology and biochemistry》2006,32(2):105-112
The levels of various ions (Na+, Cl−, Ca2+, Mg2+, K+) in the fluid phase of the gastrointestinal contents and of the plasma were determined in four teleosts with different feeding habits: traira (Hoplias malabaricus), hassar (Hoplosternum littorale), silver catfish (Rhamdia quelen), and grass carp (Ctenopharyngodon idella). The results showed that most ionic levels in the fluid phase of the gastrointestinal tract seem to be affected by feeding habit and that these levels can be different from those found in the plasma. In practical terms, these results suggest that ionic levels of the gastrointestinal contents should be considered when preparing solutions for studies of intestinal absorption in fishes. 相似文献
65.
66.
Steffen S. Madsen Stephen D. McCormick Graham Young Jeanette S. Endersen Richard S. Nishioka Howard A. Bern 《Fish physiology and biochemistry》1994,13(1):1-11
Several experiments were performed to investigate the physiology of seawater acclimation in the striped bass, Morone saxatilis. Transfer of fish from fresh water (FW) to seawater (SW; 31–32 ppt) induced only a minimal disturbance of osmotic homeostasis.
Ambient salinity did not affect plasma thyroxine, but plasma cortisol remained elevated for 24h after SW transfer. Gill and
opercular membrane chloride cell density and Na+,K+-ATPase activity were relatively high and unaffected by salinity. Average chloride cell size, however, was slightly increased
(16%) in SW-acclimated fish. Gill succinate dehydrogenase activity was higher in SW-acclimated fish than in FW fish. Kidney
Na+, K+-ATPase activity was slightly lower (16%) in SW fish than in FW fish. Posterior intestinal Na+,K+-ATPase activity and water transport capacity (Jv) did not change upon SW transfer, whereas middle intestinal Na+,K+-ATPase activity increased 35% after transfer and was correlated with an increase in Jv (110%). As salinity induced only minor changes in the osmoregulatory organs examined, it is proposed that the intrinsic euryhalinity
of the striped bass may be related to a high degree of “preparedness” for hypoosmoregulation that is uncommon among teleosts
studied to data. 相似文献
67.
Stephen D. McCormick Christopher D. Moyes James S. Ballantyne 《Fish physiology and biochemistry》1989,6(4):243-254
The effect of seawater acclimation and adaptation to various salinities on the energetics of gill and kidney of Atlantic salmon (Salmo salar) was examined. Smolts and non-smolts previously reared in fresh water were exposed to a rapid increase in salinity to 30 ppt. Plasma osmolarity, [Na+], [Cl–], [K+] and [Mg++] increased in both groups but were significantly lower in smolts than non-smolts. Gill Na+, K+-ATPase specific activity, initially higher in smolts, increased in both groups after 18 days in seawater. Kidney Na+, K+-ATPase specific activity was not affected by salinity in either group. Gill and kidney citrate synthase specific activity was not affected by seawater exposure in smolts but decreased in non-smolts. In a second experiment, Atlantic salmon smolts reared in fresh water were acclimated to 0, 10 or 30 ppt seawater for 3 months at a temperature of 13–14°C. Gill Na+, K+-ATPase was positively correlated with salinity, displaying 2.5- and 5-fold higher specific activity at 10 and 30 ppt, respectively, than at 0 ppt. Kidney Na+, K+-ATPase specific activity was not significantly affected by environmental salinity. Citrate synthase and cytochrome c oxidase specific activities in gill were slightly (6–13%) lower at 10 ppt than at 0 and 30 ppt, whereas kidney activities were lowest at 30 ppt. Oxygen consumption of isolated gill filaments was significantly higher when incubated in isosmotic saline and at 30 ppt than at 0 ppt, but was not affected by the prior acclimation salinity. The results indicate that although high salinity induces increased gill Na+, K+-ATPase activity, it does not induce substantial increases in metabolic capacity of gill or kidney. 相似文献
68.
A. Rodríguez M.A. Gallardo E. Gisbert S. Santilari A. Ibarz J. Sánchez F. Castelló-Orvay 《Fish physiology and biochemistry》2002,26(4):345-354
The osmoregulation capabilities of juvenile Siberian sturgeon exposed to three experimental osmolalities (22, 250 and 387 mOsmol kg−1) were studied over a 45-day period. Growth performance, haematological parameters, ion concentrations, gill and spiral valve
Na+-K+-ATPase activities, as well as gill and spiral valve histology, were measured. At the end of the period, the plasma osmolality
of fish kept in 250 and 387 mOsmol kg−1 was higher than that of fish kept in 22 mOsmol kg−1. Similar trends were observed in electrolyte concentrations. Spiral valve and gill Na+-K+-ATPase activity varied with exposure time and environmental salinity. Shortly after being transferred to hyperosmotic media,
spiral valve Na+-K+-ATPase activity fell, while gill Na+-K+-ATPase activity remained constant. At the end of the experiment, gill Na+-K+-ATPase activities in fish kept in isosmotic and hyperosmotic media had increased in comparison to those of the control fish.
Moreover, spiral valve Na+-K+-ATPase activities recovered and were similar to those recorded in fish kept in hyposmotic environments. Although some of
the morpho-physiological mechanisms were operational in juvenile Siberian sturgeon in their adaptation to hyperosmotic media,
fish cannot be considered hyperosmotic regulators as they were unable to maintain their plasma osmolality and electrolyte
equilibrium in salinities higher than 250 mOsmol kg−1. This suggests that the culture of juvenile Siberian sturgeon in brackish environments is unlikely to be successful. However,
our data indicate that in natural environments, juvenile Siberian sturgeon in migratory populations (Ob and Lena Rivers) would
be able to migrate successfully into estuarine brackish grounds with a salinity of up to 9%.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
69.
70.
在5~35℃区间设六个温度条件,研究了环境温度对鸡饲粮干物质表观代谢率(ADMR)、干物质真代谢(TDMR)、表观代谢能(AME)、真代谢能(TME)及血液中甲状腺激素水平的影响,并探讨了干物质代谢率、内源性干物质(EDM)、内源性能量(EEL)排出量及代谢能等与血浆中甲状腺激素水平的关系。共用78只成年京白公鸡进行了测定。结果表明:环境温度显著影响ADMR、TDMR、EDM、EEL、AME、TME及血浆中三碘甲腺原氨酸(T_3)的水平。ADMR、AME、EDM、EEL、TDMR、TME、血浆中T_3浓度与环境温度关系呈曲线型。本试验还探讨了ADMR、AME、EDM、EEL、TDMR、TME与血浆中T_3浓度的关系,相关关系极显著,呈现出令人感兴趣的趋势,但对其进一步的生理机制有待深入研究。 相似文献