Endothelial dysfunction contributes to the development of ungulate's laminitis. Although extensively studied in equines, the endothelial function is not fully examined in bovine digital veins (BDVs). BDVs were studied under isometric conditions to describe the acetylcholine (ACh) endothelium‐dependent relaxation. Concentration–response curves were constructed to phenylephrine, ACh, and sodium nitroprusside (SNP). Relaxation responses were evaluated using either phenylephrine or depolarizing high‐potassium Krebs solution (DKS) as precontraction agents. Endothelium denudation and incubation with L‐NAME (300 μM), indomethacin (10 μM) or both were used to explore endothelial‐mediated mechanisms. Endothelium denudation did not modify phenylephrine and SNP responses, however, significantly (p < 0.05) converted a relaxation (63.2 ± 5%) response to ACh into a contraction (30.3±9%). The ACh‐evoked relaxation was significantly (p < 0.05) reduced in the presence of indomethacin (37.5 ± 6%) and L‐NAME (6.40 ± 2%). The presence of both inhibitors abolished the ACh‐evoked relaxation. Although DKS caused a higher precontraction than phenylephrine, ACh‐evoked relaxation (22.4 ± 3.4%) was still observed and was reduced by the combination of inhibitors (7.0 ± 1.0%). The ACh endothelium‐dependent relaxation in BDVs is essentially mediated by nitric oxide and endothelium‐derived prostanoids. The BDV endothelium function is a dynamic component in the control of the bovine digital blood flow, particularly under endothelial dysfunction conditions when venoconstriction might lead to postcapillary resistance increase. 相似文献
1. Infectious laryngotracheitis is a respiratory disease that affects the poultry industry worldwide. It is common in flocks with high-bird density, causing major economic losses.
2. In this study, a SYBR® FAST polymerase chain reaction (PCR) double-strand DNA intercalating agent assay was performed for the detection of infectious laryngotracheitis virus (ILTV) in clinical samples in comparison with a conventional nested-PCR, both based on the glycoprotein E encoding gene. This assay amplified 56 bp and was capable of detecting 19 to 1 copies of virus.
3. In total, 164 clinical samples were obtained from birds with respiratory problems from the period of 2009–2016. In the nested-PCR, there were 45.12% positive samples and 54.88% negative samples, while in the real-time PCR (qPCR), there were 81.1% positive samples and 18.9% negative samples.
4. In conclusion, qPCR from the DNA double-strand intercalating agent SYBR® GREEN FAST was useful for the diagnosis of ILTV because it detected samples that were negative in nested-PCR. This assay has advantages, such as a shortened processing-time, and no need for post-amplification processing (electrophoresis) with additional reagents, such as MgCl2 and agarose. Hence, qPCR proved to be useful, rapid and low cost for use with clinical samples. 相似文献
Thirty days before expected time of parturition, 20 Holstein cows were divided into ?Cr and +Cr groups. From day 25 before parturition (BP ) up to day 30 after parturition (AP ), +Cr cows received 10 mg of Cr (chromium‐enriched yeast) daily. Muscle and adipose tissue samples were taken at days ?30, ?10, +7 and +10 related to parturition, when body condition score (BCS ) was also determined. Hepatic tissue samples were taken at days ?10 and +7. Tissue samples were used for determination of the insulin signalling pathway protein expressions. Intravenous glucose tolerance test (IVGTT ) was performed at days ?28, ?7, +10 and +30. Milk yield was recorded during first 14 weeks AP . Milk composition was obtained at days 7 and 28 AP . At day 10 BP , protein content of β ‐subunit of insulin receptor (IR β ) was significantly higher (p ? 0.05) in muscle, and phosphorylation of insulin receptor substrate 1 at serine 307 (pIRS ‐1 Ser307) was significantly lower (p ? 0.05) in hepatic tissue of +Cr group. After parturition, pIRS ‐1 Ser307 was significantly lower in muscle tissue at days 7 and 28 (p ? 0.05 and p ? 0.001, respectively), while phosphorylation of Akt at serine 473 (pA kt Ser473) was significantly higher (p ? 0.01) in hepatic tissue at day 7 AP in +Cr group. Chromium had opposite effect on insulin kinetics during IVGTT s obtained BP and AP . Insulin secretion was significantly reduced at day 7 BP and significantly enhanced at day 10 AP , when NEFA concentration was also significantly increased. Milk yield and ECM value were depressed in +Cr group. DMI and BCS were significantly enhanced in +Cr group at day 7 BP . In conclusion, chromium modulates insulin signalling pathway in dairy cows, but targeted signalling molecules are different in antepartal then post‐partal period, probably due to duration of exposure to chromium and different energy status between those periods. 相似文献
Amniotic fluid is a rich source of multipotent mesenchymal stem cells (MSCs). Amniotic fluid stem cells (AFSCs) have become a new source of stem cells; they have low immunogenicity and are easily harvested. For this reason, they may be useful in clinical tissue engineering. Moreover, AFSCs have anti‐inflammatory properties and can repair tissues. This study evaluated the utility of AFSC injection to treat bilateral ovarian dystrophy in Holstein‐Friesian cows. Bovine AFSCs (BAFSCs) were collected at slaughter from Holstein‐Friesian cows during the third or fourth month of pregnancy and cultured in vitro. The BAFSCs began to show a fibroblast‐like morphology. They were positive for β‐integrin, CD44, CD73, CD106 and Oct4 and negative for CD34 and CD45. After induction, the cells differentiated into mesodermal lineages. Bilateral ovarian dystrophy was confirmed by ultrasonography in 16 lactating cows. The subsequent experiment lasted 15 weeks. Serum was collected weekly to analyse progesterone concentrations, and weekly ultrasonography recorded ovarian changes. Each cow was equipped with an automatic heat detection system to facilitate oestrus observation and breeding records. The progesterone concentration of two cows in the treatment group (25%) significantly increased during weeks 10–15. On ultrasonography, the treatment group demonstrated mature follicles after BAFSCs injection, and foetuses were visualized approximately 40 days after artificial insemination (AI). Oestrus rates in the control and treatment groups were 0% (0/8) and 50% (4/8), respectively; pregnancy rates were 0% (0/8) and 25% (2/8), respectively. Calves were successfully delivered in both cases of pregnancy. These results show that BAFSCs can alleviate bovine ovarian dystrophy and restore fertility. 相似文献