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排序方式: 共有596条查询结果,搜索用时 15 毫秒
11.
F. TÓTH N. FRANK T. MARTIN‐JIMÉNEZ S. B. ELLIOTT R. J. GEOR R. C. BOSTON 《Equine veterinary journal》2010,42(2):149-155
Reasons for performing study: Hyperinsulinaemia is detected in horses with insulin resistance (IR) and has previously been attributed to increased pancreatic insulin secretion. Connecting peptide (C‐peptide) can be measured to assess pancreatic function because it is secreted in equimolar amounts with insulin and does not undergo hepatic clearance. Hypothesis: A human double antibody radioimmunoassay (RIA) detects C‐peptide in equine serum and concentrations would reflect responses to different stimuli and conditions. Methods: A validation procedure was performed to assess the RIA. Six mature mares were selected and somatostatin administered i.v. as a primed continuous rate infusion, followed by 50 nmol human C‐peptide i.v. Insulin and C‐peptide concentrations were measured in horses (n = 6) undergoing an insulin‐modified frequently sampled i.v. glucose tolerance test, and in horses with insulin resistance (n = 10) or normal insulin sensitivity (n = 20). Results: A human RIA was validated for use with equine sera. Endogenous C‐peptide secretion was suppressed by somatostatin and median (range) clearance rate was 0.83 (0.15–1.61) ml/min/kg bwt. Mean ± s.d. C‐peptide‐to‐insulin ratio significantly (P = 0.004) decreased during the glucose tolerance test from 3.60 ± 1.95 prior to infusion to 1.03 ± 0.18 during the first 20 min following dextrose administration. Median C‐peptide and insulin concentrations were 1.5‐ and 9.5‐fold higher, respectively in horses with IR, compared with healthy horses. Conclusions: Endogenous C‐peptide secretion decreases in response to somatostatin and increases after dextrose infusion. Results suggest that relative insulin clearance decreases as pancreatic secretion increases in response to dextrose infusion. Hyperinsulinaemia in insulin resistant horses may be associated with both increased insulin secretion and decreased insulin clearance. Potential relevance: Both C‐peptide and insulin concentrations should be measured to assess pancreatic secretion and insulin clearance in horses. 相似文献
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Michael M Garner Sonia M Hernandez-Divers James T Raymond 《Veterinary Clinics of North America: Exotic Animal Practice》2004,7(3):653-71, vi
This retrospective study appears to be the largest publication to date regarding the prevalence of neoplasia in reptiles. As in previous publications, neoplasia is most common in snakes, followed by lizards, chelonians, and crocodilians. Several interesting trends were documented in this study, some of which appear to be previously unidentified, and some that support the findings of previous publications. 相似文献
14.
Zhang Q Lin J Pereira S 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2003,4(2):63-71
Thermophilic Campylobacter species, including Campylobacter jejuni and Campylobacter coli, are responsible for foodborne campylobacteriosis in humans and are increasingly resistant to fluoroquinolone (FQ) antimicrobials. The therapeutic use of FQ antimicrobial agents in food animal production, particularly in poultry, has become a concern for public health, because the practice may promote the emergence of FQ-resistant Campylobacter that can be transmitted to humans through the food chain. Recent studies have indicated that Campylobacter displays a hypermutable phenotype in response to in vivo treatment with FQ antimicrobials, resulting in the rapid emergence of resistant mutants. Distinct from other Gram-negative bacteria, the acquisition of FQ resistance in Campylobacter does not require stepwise accumulation of gyrA mutations and overexpression of efflux pumps, and is mainly mediated by single-step point mutations in gyrA in the presence of a constitutively expressed multidrug efflux pump, CmeABC. The simplicity of the resistance mechanisms may facilitate the rapid adaptation of Campylobacter to FQ treatment. The FQ-resistant Campylobacter mutants derived from chickens do not show a fitness cost in vivo and are ecologically competitive in the colonization of chickens even in the absence of antimicrobial selection pressure. These findings suggest that FQ-resistant Campylobacter may continue to persist regardless of antimicrobial usage, and highlight the need for extra effort to prevent the occurrence and spread of FQ-resistant Campylobacter in animal reservoirs. 相似文献
15.
ALEJANDRO VALDÉS-MARTÍNEZ RACHEL CIANCIOLO WILFRIED MAI 《Veterinary radiology & ultrasound》2007,48(4):357-360
The purpose of this study was to investigate the association between renal hypoechoic subcapsular thickening observed ultrasonographically and the presence of renal lymphosarcoma in cats. The ultrasonography database was retrospectively searched for cats that underwent ultrasound examination and ultrasound guided needle renal aspirate, renal biopsy, or necropsy. One radiologist unaware of the final diagnosis evaluated the images for the presence of hypoechoic subcapsular thickening and other abnormal findings. Fifty-four cats met the inclusion criteria. Hypoechoic subcapsular thickening was found in 21 cats of which 17 had lymphosarcoma; the remaining four cats had a different diagnosis. Eleven out of 33 cats without hypoechoic subcapsular thickening were positive for lymphosarcoma, and the rest had a different diagnosis. There was a significant association between hypoechoic subcapsular thickening and renal lymphosarcoma (P = 0.001). The positive predictive value of hypoechoic subcapsular thickening for lymphosarcoma was 80.9% and the negative predictive value was 66.7%. The sensitivity and specificity of hypoechoic subcapsular thickening for the diagnosis of renal lymphosarcoma were 60.7% and 84.6%, respectively. The results of this study indicate that the presence of hypoechoic subcapsular thickening in feline kidneys is associated with renal lymphosarcoma. 相似文献
16.
Comparative study of the characteristics of the carcass and the meat of the Chato Murciano pig and its cross with Iberian pig, reared indoors 总被引:1,自引:0,他引:1
Miguel GALIÁN Begoña PEINADO Carmen MARTÍNEZ María J. PERIAGO Gaspar ROS Angel POTO 《Animal Science Journal》2007,78(6):659-667
The Chato Murciano pig is a breed catalogued as a Special Protection breed in danger of extinction. At present it is commonly reared in an intensive system. We have studied the mineral composition and other characteristics of its carcass and meat. Samples from the Musculus longissimus lumborum were taken from a total number of 43 animals, divided into two groups, Chato Murciano and Chato Murciano crossed with Iberian, reared in a conventional indoor system. The resulting meat of the Chato Murciano pig and its cross with Iberian was especially rich in iron and copper, rich in phosphorus, and marginally poor in calcium and sodium. The evolution of the pH of the carcass was that of pigs which do not produce PSE (pale, soft and exudative) meat. Some relevant positive correlation coefficients between minerals (P ≤ 0.05) have been found. 相似文献
17.
We studied stomatal responses to decreasing predawn water potential (Psipd) and increasing leaf-to-air water vapor pressure difference (VPD) of co-occurring woody Mediterranean species with contrasting leaf habits and growth form. The species included two evergreen oaks (Quercus ilex subsp. ballota (Desf.) Samp. and Q. suber L.), two deciduous oaks (Q. faginea Lam. and Q. pyrenaica Willd.) and two deciduous shrubs (Pyrus bourgaeana Decne. and Crataegus monogyna Jacq.). Our main objective was to determine if stomatal sensitivity is related to differences in leaf life span and leaf habit. The deciduous shrubs had the least conservative water-use characteristics, with relatively high stomatal conductance and low stomatal sensitivity to soil and atmospheric drought. As a result, Psipd decreased greatly in both species during the growing season, resulting in early leaf abscission in the summer. The deciduous oaks showed intermediate water-use characteristics, having maximum stomatal conductances and CO2 assimilation rates similar to or even higher than those of the deciduous shrubs. However, they had greater stomatal sensitivity to soil drying and showed less negative Psipd values than the deciduous shrubs. The evergreen oaks, and especially the species with the greatest leaf longevity, Q. ilex, exhibited the most conservative water-use behavior, having lower maximum stomatal conductances and greater sensitivity to VPD than the deciduous species. As a result, Psipd decreased less during the growing season in the evergreens than in the deciduous species, which may contribute to greater leaf longevity by avoiding irreversible damage during the summer drought. However, the combination of low maximum CO2 assimilation rates and high stomatal sensitivity to drought must have a negative impact on the final carbon budget of leaves with a long life span. 相似文献
18.
ABSTRACT Applied behavior analysis can be used by development practitioners to improve the design and implementation of development programs. Programs are most successful when the goals and consequences of change agents, strategists, and adopters align, as we demonstrate with real-world examples from international agroforestry projects. We focus on the role of change agents acting as intermediaries between change strategists, such as large development agencies, and development adopters, the rural farmers who implement agroforestry projects. We describe three aspects that are particularly important for agroforestry projects: (1) identifying the rules being used, (2) assessing the roles and reinforcement contingencies of both individuals and larger groups, and (3) being flexible and able to respond to rapid change. 相似文献
19.
Irrigation effects on quality, phenolic composition, and selected volatiles of virgin olive oils cv. Leccino 总被引:1,自引:0,他引:1
Servili M Esposto S Lodolini E Selvaggini R Taticchi A Urbani S Montedoro G Serravalle M Gucci R 《Journal of agricultural and food chemistry》2007,55(16):6609-6618
Field-grown olive trees (Olea europaea L. cv. Leccino) were used over two growing seasons to determine the effect of deficit irrigation regimes on virgin olive oil (VOO) quality. Drip irrigation was managed to maintain a predawn leaf water potential (PLWP): (a) higher than -1.1 MPa (full irrigation: FI); (b) between -1.0 and -3.3 MPa (deficit irrigation: DI); (c) higher than -4.2 MPa (severe deficit irrigation: SI). The fruit yield and oil yield of DI trees were over 90% of those of FI treatments in both years, respectively, whereas yields of SI trees ranged from 61 to 76%. The irrigation regime had minor effects on the free acidity, peroxide value, and fatty acid composition of VOO. The concentrations of phenols and o-diphenols in VOO were negatively correlated with PLWP. The concentrations of the dialdehydic form of decarboxymethyl elenolic acid linked to (3,4-dihydroxyphenyl)ethanol (3,4-DHPEA-EDA), the isomer of the oleuropein aglycon (3,4-DHPEA-EA), and the dialdehydic form of decarboxymethyl elenolic acid linked to (p-hydroxyphenyl)ethanol (p-HPEA-EDA) were lower in FI than in SI treatments. The concentrations of lignans (+)-1-acetoxipinoresinol and (+)-1-pinoresinol were unaffected by the irrigation regime. The tree water status had a marked effect on the concentration of volatile compounds, such as the C(6)-saturated and unsaturated aldehydes, alcohols, and esters. 相似文献
20.
Bassarello C Bifulco G Montoro P Skhirtladze A Benidze M Kemertelidze E Pizza C Piacente S 《Journal of agricultural and food chemistry》2007,55(16):6636-6642
On the basis of the biological activities exhibited by the phenolic constituents of Yucca schidigera, the antioxidant activity of the methanol extract of Yucca gloriosa roots was evaluated in the TEAC assay. The strong activity exerted by this extract prompted investigation of its phenolic constituents, yielding three new phenolic derivatives, gloriosaols C, D, and E, along with gloriosaols A and B previously isolated from Y. gloriosa roots and yuccaols C-E isolated from Y. schidigera. ESIMS and NMR data of gloriosaols C-E closely resembled those reported for gloriosaols A and B, two diasteroisomers characterized by unusual spirostructures. Careful inspection of ROESY spectra revealed that gloriosaols C-E are diastereoisomers of gloriosaols A and B. A possible assignment of the relative configuration of gloriosaols C-E, derived according to an integrated NMR-quantum mechanical (QM) approach, which was already applied to the determination of the stereostructures of gloriosaols A and B, is also proposed. Gloriosaols A-E exhibited potent antioxidant activity measured by the TEAC assay, showing the potential use of Y. gloriosa as a source of antioxidant principles. 相似文献