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71.
Dynamics in the membrane organization of the mammalian sperm cell and functionality in fertilization
The capacitation process of sperm cells involves complex changes in the composition and orientation of molecules at the surface of the sperm cell. Here we focus on the lipid architecture in the sperm plasma membrane and demonstrate that the sperm plasma membrane is not static but is an extremely dynamic structure. Advanced fluoroscopic techniques enabled continuous monitoring of lipid organization in living cells and extremely rapid lipid movements were observed. The orientation of lipids in the sperm plasma membrane changed under capacitative treatments, was found to be sensitive for temperature and also changed upon binding of sperm cells to the zona pellucida. The changes in membrane properties coincided with an activation of protein kinases resulting in tyrosine phosphorylation of specific plasma membrane proteins. The detected membrane changes relate to intrinsic membrane properties such as fluidity, permeability, adhesiveness and fusibility. We think that these results may provide a physiological basis for new assays, able to discriminate between functional and non-physiological sperm cells. 相似文献
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Kovalik M Thoday KL Handel IG Bronsvoort BM Evans H van den Broek AH Mellanby RJ 《Veterinary dermatology》2011,22(2):173-180
The effect of ciclosporin A (CsA) on glucose homeostasis was investigated in 16 dogs with atopic dermatitis by determining plasma glucose, serum fructosamine and insulin concentrations, and serial insulin and glucose concentrations following a glucagon stimulation test, before and 6 weeks after CsA therapy at 5 mg/kg once daily. All dogs completed the study. Following CsA treatment, the median serum fructosamine concentrations were significantly higher (pretreatment 227.5 μmol/L; post-treatment 246.5 μmol/L; P = 0.001; reference range 162-310 μmol/L). Based on analyses of the areas under concentration-time curves (AUC) pre- and post-CsA treatment, plasma glucose concentrations were significantly higher (AUC without baseline correction 31.0 mmol/L/min greater; P = 0.021) and serum insulin concentrations were significantly lower (AUC without baseline correction 217.1 μIU/mL/min lower; P = 0.044) following CsA treatment. Peak glucose concentrations after glucagon stimulation test were significantly higher following CsA treatment (10.75 versus 12.05 mmol/L; P = 0.021), but there was no significant difference in peak serum insulin (52.0 versus 35.0 μIU/mL; P = 0.052). There was a negative correlation between baseline uncorrected insulin AUC and trough serum log CsA concentrations (r = -0.70, P = 0.005). The administration of CsA to dogs with atopic dermatitis leads to disturbances in glucose homeostasis. The clinical significance of this is unclear, but it should be taken into account when considering CsA treatment in dogs that already have such impairments. 相似文献
74.
Cox S Martin-Jimenez T van Amstel S Doherty T 《Journal of veterinary pharmacology and therapeutics》2011,34(3):259-264
The purpose of this study was to determine the pharmacokinetics of tramadol and its metabolite M1 after intravenous and intramuscular administration to llamas. Tramadol, a centrally acting analgesic whose efficacy is a result of complex interactions between opiate, adrenergic and serotonin receptor systems, has been used clinically to treat moderate to severe pain in humans. The pharmacokinetic parameters of tramadol and M1 in plasma were examined following intravenous and intramuscular administration to six healthy male llamas. Tramadol half-life, volume of distribution at steady-state and clearance after intravenous administration were 2.12 ± 0.37 h, 4.02 ± 1.16 L/kg and 1728.73 ± 152.82 mL/h/kg, respectively. The bioavailability was 110 ± 21% and half-life 2.54 ± 0.31 h following intramuscular administration of tramadol. M1 had a half-life of 10.40 ± 2.90 h and 7.71 ± 0.54 h following intravenous and intramuscular administration of tramadol. 相似文献
75.
Insect bite hypersensitivity (IBH) is a seasonal allergic skin disease in horses caused by bites of certain Culicoides spp. The aim of our study was to investigate the maternal effect on IBH and to estimate the heritability and repeatability of IBH in the Dutch Friesian horse population. Data consisted of 3,453 Dutch Friesian broodmares with 3,763 visual observations on IBH clinical symptoms scored by 12 inspectors during organized foal inspections in 2004 and 2008. Nine percent of the mares (n = 310) were scored in both years. Mares descended from 144 sires and 2,554 dams and 26.2% of the dams (n = 669) had more than 1 offspring in the data set (range: 2 to 6). Insect bite hypersensitivity was analyzed as a binary trait with a threshold animal model with and without a maternal effect, using a Bayesian approach. Observed IBH prevalence in Dutch Friesian broodmare population was 18.2%. Heritability on the liability scale was 0.16 (SD = 0.06); heritability on the observed scale was 0.07; and repeatability was 0.89 (SD = 0.03). Maternal effect was 0.17 (SD = 0.06) and significantly differed from zero, although the animal model without a maternal effect fitted the data better. These results show that genetic and permanent environmental factors affect IBH in Dutch Friesian horses. The dam affected the IBH development of her offspring through an additive genetic influence but also by being part of their rearing environment. 相似文献
76.
Lam TJ Jansen J van den Borne BH Renes RJ Hogeveen H 《New Zealand veterinary journal》2011,59(1):8-15
The veterinary practitioner is one of the most important advisors for farmers in the field of udder health. He or she has the tools to improve udder health if farmers are motivated to do so. Many farmers think that udder health is important, but this does not always mean that management of mastitis is up to standard. Many veterinarians are of the opinion that they are unable to convince their clients of the possible profits to be gained from investing in management of mastitis. Something is required to bridge this gap. This article, based on data and experiences from The Netherlands, describes the communication issues that can be considered in order to improve the role of the veterinarian as advisor, to achieve better udder health. The outcome is beneficial for both farmers and veterinarians, the former for reasons of economics, welfare and ease of work; the latter because it creates extra, challenging work. It is concluded that the veterinary practitioner is in an ideal situation to advise and motivate farmers to improve udder health but, to do this, the means of communication need to take account of the different learning styles of farmers. The most important aspects of such communication are found to be a pro-active approach, personalisation of messages, providing a realistic frame of reference for the farmer, and use of the farmer's social environment. Importantly, all persons and organisations in a farmer's social environment should articulate the same message. 相似文献
77.
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79.
A retrospective study was carried out of 224 horses operated for strangulating small intestine obstructions. Fifty-four horses were euthanized and 5 horses died during surgery which means that 165 (73%) were allowed to recover. Of these, 53 horses were euthanized or died in the clinic and 112 (50%) were discharged from the hospital. Of 90 horses available for follow-up 1 year postoperatively, 76 (84%) were still alive. The most important causes of death or reasons for euthanasia in the direct post-operative period were post-operative paralytic ileus, (adhesive) peritonitis and intra-abdominal haemorrhage. After discharge from the hospital the reasons were (adhesive) peritonitis and (recurrent) colic. Of the horses which survived for at least 1 year, 16% sometimes suffered from colic, 12% experienced problems with incisional woundhealing and 4% suffered from jugular vein thrombosis. All were in good or reasonable condition and 88% performed at (approximately) the same level as before the operation. The type of surgical intervention (i.e. enterotomy, enterectomy) did not significantly influence the outcome of surgery, whereas the type of anastomosis did. End-to-end jejunojejunostomy had a better prognosis than side-to-side jejunocaecostomy. It was concluded that strangulating obstructions of the small intestine still carry a poor to guarded prognosis. Mortality was highest in the direct peri-operative period. Once discharged from hospital, prognosis can be considered to be fair to good. Attempts to improve outcome should be directed at a better handling of the ileal stump during surgery and at the prevention of post-operative ileus and the formation of adhesions. 相似文献
80.
Busschers E van Weeren PR 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2001,48(7):413-427
The flexion test of the distal limb is a commonly used clinical tool in both lame and sound horses. In the latter use it is given some predictive value. In recent studies it has been shown that examiner-related factors (force, time) may strongly influence the outcome of the test. In the present study, the possible influences of a number of horse-related factors and short- and long-term repeatability were investigated. Flexion tests were performed by the same researcher in 100 clinically sound horses under standardized conditions. The outcome of the test was scored on a 9-point semiquantitative scale. The maximum flexion angles of the fetlock joints were measured and the range of motion (ROM) of the fetlock joint was calculated. In the second part of the study, flexion tests were repeated, at intervals of 10 min, 30 min, 48 h and 6 months in 23 horses to assess repeatability. Over 60% of the 100 sound horses had a positive flexion test. Of these, about 50% showed a slight lameness, 35% a mild lameness, and 15% a distinct lameness. There was no influence of weight, height or ROM on the score of the flexion test. The outcome of the flexion test increased significantly with age and was significantly higher in mares than in geldings. When repeating the flexion test with short intervals of 10 and 30 min, the score increased significantly after the second test. Repeated flexion after 48 h did not result in a significantly different outcome. Over a 6-month period, the outcome of the test decreased significantly and the ROM increased significantly. It is concluded that most clinically sound horses have a (slightly) positive flexion test of the distal limb. This and the lack of long-term consistency of the test cast doubt on the presumption that a positive flexion test may be an indication for subclinical joint disorders and question the possible value of the test as a predictor of future joint-related problems. There exists a wide individual variation in ROM of the fetlock joint with, in sound horses, no relationship between ROM and the outcome of the flexion test. The factors age and gender should be taken into account when interpreting the results of a flexion test. 相似文献