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551.
Clinical and subclinical endometritis are common causes of infertility and subfertility in high producing dairy cattle, delaying the onset of ovarian cyclic activity after parturition, extending luteal phases and reducing conception rates. Escherichia coli and Arcanobacterium pyogenes cause endometrial damage and inflammation. Components of microbes, such as lipopolysaccharide (LPS), are detected by Toll-like receptors on endometrial cells, leading to secretion of cytokines, chemokines and antimicrobial peptides. Long luteal phases associated with endometritis are probably caused by a switch in endometrial prostaglandin production from prostaglandin F2a (PGF) to prostaglandin E2 . In addition, LPS impairs the function of the hypothalamus and pituitary, and directly perturbs ovarian granulosa cells steroidogenesis, providing mechanisms to explain the association between uterine disease and anovulatory anoestrus. Cows with uterine disease that ovulate have lower peripheral plasma progesterone concentrations that may further reduce the chance of conception associated with endometritis. 相似文献
552.
Jordheim M Aaby K Fossen T Skrede G Andersen ØM 《Journal of agricultural and food chemistry》2007,55(26):10591-10598
To improve accuracy in the determination of anthocyanin purity and succeeding antioxidant capacity, 1H and 13C nuclear magnetic resonance spectroscopy have been combined with high-performance liquid chromatography (HPLC) equipped with a diode array detector and UV-vis spectroscopy in the analysis of anthocyanidin 3-glycosides and 5-carboxypyranoanthocyanidin 3-glycosides. The molar absoptivity (epsilon) values were found to be relatively similar, in contrast to previously reported literature values, and the average epsilon values for both anthocyanidin 3-monoglycosides and 5-carboxypyranoanthocyanidin 3-glycosides were proposed to be 22,000 and 23,000 in acidified aqueous and methanolic solutions, respectively. To assess the influence of structure on the potential antioxidant capacity of anthocyanins, the 3-glucosides of pelargonidin (1), cyanidin (2), peonidin (3), delphinidin (4), petunidin (5), malvidin (6), 5-carboxypyranopelargonidin (8), 5-carboxypyranocyanidin (9), 5-carboxypyranodelphinidin (11), 5-carboxypyranopetunidin (12), and 5-carboxypyranomalvidin (13) and the 3-galactosides of cyanidin (7) and 5-carboxypyranocyanidin (14) were examined by a ferric ion reducing antioxidant power (FRAP) assay. The reducing capacities of the individual anthocyanins were in the range of 0.9-5.2 micromol of Trolox equivalents/micromol. The two 5-carboxypyranoanthocyanins 11 and 9 and the four common anthocyanins 2, 4, 7, and 14, all possessing pyrogallol or catechol type of B rings, showed the highest antioxidant capacity measured by FRAP. However, the inclusion of the 5-hydroxyl in the D ring and just one oxygen substituent on the B ring in 8 diminished the reducing capacity considerably. Correspondingly, electrochemical behavior of 5-carboxypyranoanthocyanidin 3-glucosides and anthocyanidin 3-glucosides was derived using HPLC coupled to a coulometric array detector set from 100 to 800 mV in increments of 100 mV. The relative order of the reducing capacity of the various 5-carboxypyranoanthocyanidin 3-glucosides and anthocyanidin 3-glucosides were nearly alike, whether determined by coulometric array detection or FRAP. 相似文献
553.
Puerarin and conjugate bases as radical scavengers and antioxidants: molecular mechanism and synergism with beta-carotene 总被引:2,自引:0,他引:2
Han RM Tian YX Becker EM Andersen ML Zhang JP Skibsted LH 《Journal of agricultural and food chemistry》2007,55(6):2384-2391
The 4'-hydroxyl group of puerarin, a C-glycoside of the isoflavonoid daidzein, was shown, using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical cation and stopped-flow spectroscopy and by comparison with the 7-propylpuerarin (A ring derivative) and 4'-propylpuerarin (B ring derivative), to be a more efficient radical scavenger as compared to the 7-hydroxyl group by a factor of 2, a difference increasing upon deprotonation. The difference in radical scavenging agreed with the oxidation potentials (cyclic voltammetry in acetonitrile, 0.1 M Bu4NBF4 at 25 degrees C): E/mV=862+/-3 for puerarin, 905+/-10 for 7-propylpuerarin, and 1064+/-2 for 4'-propylpuerarin relative to ferrocene/ferricenium. In aqueous solution, the reduction potential was shown to decrease for increasing pH, and deprotonation of the 4'-hydroxyl group increased radical scavenging more than deprotonation of the 7-hydroxyl group. The 7-hydroxyl was found to be more acidic (pKa1=7.20+/-0.01 in puerarin and pKa=7.23+/-0.01 in 4'-propylpuerarin) than the 4'-hydroxyl group (pKa2=9.84+/-0.08 in puerarin and pKa=9.51+/-0.02 in 7-propylpuerarin); aqueous solution, ionic strength of 0.1, and 25 degrees C. In phosphatidyl choline liposome of pH 7.4, puerarin and beta-carotene each showed a modest antioxidant activity measured as prolongation of the lag phase for formation of conjugate dienes and using the water-soluble radical initiator APPH with effects of puerarin and beta-carotene being additive. For the lipophilic initiator AMVN, the antioxidative effect decreased for puerarin and increased for beta-carotene as compared to APPH and showed a clear synergism. A regeneration of beta-carotene, effective in the liposome lipid phase as antioxidant, from the cation radical by deprotonated forms of puerarin was demonstrated in 9:1 chloroform/methanol using laser flash photolysis with k2=2.7x10(4) L mol-1 s-1 for the bimolecular process between the cation radical and the puerarin dianion. 相似文献
554.
Bertram HC Kristensen M Østdal H Baron CP Young JF Andersen HJ 《Journal of agricultural and food chemistry》2007,55(6):2342-2348
Water-binding properties of myofibrils extracted from porcine muscle, and added hemoglobin with and without exposure to H2O2, were characterized using low-field proton NMR T2 relaxometry. The effects of pH and ionic strength in the samples were investigated as pH was adjusted to 5.4, 6.2, and 7.0 and ionic strength was adjusted to 0.29, 0.46, and 0.71 M, respectively. The formation of dityrosine as a measure of oxidative protein cross-linking revealed a significant increase in dityrosine concentrations upon H2O2 activation. The formation of dityrosine was strongly pH-dependent and increased with decreasing pH. In addition, increased levels of thiobarbituric acid reactive substances were observed upon addition of H2O2, implying that lipid oxidation was enhanced, however, with a different oxidation pattern as compared to the myofibrillar proteins. Low-field NMR relaxation measurements revealed reduced T2 relaxation times upon H2O2 activation, which corresponds to reduced water-holding capacity upon oxidation. However, a direct relationship between degree of oxidation and T2 relaxation time was not observed with various pH values and ionic strengths, and further studies are needed for a complete understanding of the effect of oxidation on myofibrillar functionality. 相似文献
555.
Impact assessments of fishing on a stock require parameterization of vital rates: growth, mortality and recruitment. For ‘data‐poor’ stocks, vital rates may be estimated from empirical size‐based relationships or from life‐history invariants. However, a theoretical framework to synthesize these empirical relations is lacking. Here, we combine life‐history invariants, metabolic scaling and size‐spectrum theory to develop a general size‐ and trait‐based theory for demography and recruitment of exploited fish stocks. Important concepts are physiological or metabolic scaled mortalities and flux of individuals or their biomass to size. The theory is based on classic metabolic relations at the individual level and uses asymptotic size W∞ as a trait. The theory predicts fundamental similarities and differences between small and large species in vital rates and response to fishing. The central result is that larger species have a higher egg production per recruit than small species. This means that density dependence is stronger for large than for small species and has the consequence that fisheries reference points that incorporate recruitment do not obey metabolic scaling rules. This result implies that even though small species have a higher productivity than large species their resilience towards fishing is lower than expected from metabolic scaling rules. Further, we show that the fishing mortality leading to maximum yield per recruit is an ill‐suited reference point. The theory can be used to generalize the impact of fishing across species and for making demographic and evolutionary impact assessments of fishing, particularly in data‐poor situations. 相似文献
556.
Jr P. B. Jennings G. L. Andersen W. S. Mathey C. V. Okerberg 《The Journal of small animal practice》1990,31(7):349-352
Bone haemangiosarcoma in a young Belgian malinois initially presented as an abscess involving the Tight 10th rib. The dog responded promptly to abscess drainage and antibiotics. Anaemia and thrombocytopenia began one week later and ultrasonography revealed splenic and liver lesions. Exploratory surgery identified tumour masses in the spleen, liver, lung and rib. Histopathological diagnosis was hemangiosarcoma, possibly of bone origin. 相似文献
557.
Gary K. C. Lee Courtney Barbosa Gitte Andersen Christina J. Ramirez Matthew Kornya Anthony Abrams-Ogg Katherine Morrison Gabriella Diamantino R. Darren Wood Janet Beeler-Marfisi Fernanda Ampuero Laetitia Tatiersky Dorothee Bienzle 《Journal of veterinary diagnostic investigation》2022,34(6):1006
An 8-wk-old, male, mixed-breed puppy was adopted from a rescue organization. From the time of adoption, the puppy suffered episodes of illness affecting various organ systems, which resolved with supportive therapy but relapsed once medical therapy was discontinued. Review of the hematologic data revealed cyclic fluctuations in circulating blood cells. Cyclicity was most prominent in neutrophils, with recurrent severe neutropenia. Neutropenic episodes lasted 5–6 d, with regular cycles of 11–14 d between nadir neutrophil counts. Genetic testing determined that the patient was homozygous mutant for the frameshift mutation in the adaptor protein complex 3 β-subunit (AP3B1) gene, originally identified in gray collies with cyclic hematopoiesis (CH). Pedigree information was not available, but the patient’s features were phenotypically distinct from those of collies. We describe here a case of the AP3B1 mutation in a mixed-breed dog that did not resemble a collie, undescribed previously, to our knowledge. Our findings indicate that the AP3B1 mutation and CH are present within the general canine population and are not restricted to collies. 相似文献