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建立了蜂蜜中土霉素药物残留检测的超高效液相色谱-串联质谱检测方法.以McIlvaine-Na2EDTA缓冲液为提取液,经HLB固相萃取小柱净化,脱溶剂后用甲醇水溶解,在超高效液相色谱-串联质谱上进行检测.土霉素在0~200ng·ml-1浓度范围内呈良好的线性关系,相关系数R2>0.999.添加药物水平40~200μg·kg-1的回收率在65.1~98.7%.土霉素的检测限为5μg·kg-1,定量限为10μg·kg-1.方法快速简便,准确可靠,重现性好,可用于监测蜂蜜中土霉素的含量. 相似文献
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以维氏气单胞菌的核酸酶基因为靶基因建立了PCR快速检测方法。实验证明该方法具有良好的特异性与敏感性,对维氏气单胞菌基因组DNA的最低检测浓度为1.58×10-4ng;在人工模拟试验的30份样品中:使用PCR检测方法的样本检出率达到了86.7%(26/30),高于细菌分离培养的检出率73.3%(22/30)。该方法的建立为维氏气单胞菌的快速检测提供了新的方法。 相似文献
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采用直接竞争ELISA方法检测牛奶中孕酮含量.采用碳化二亚胺法,应用辣根过氧化物酶(HRP)标记11-α羟基孕酮琥珀酸酯(11α-OH-P4-HS),制备孕酮酶标抗原;酶标抗原与牛奶样品中的孕酮共同竞争结合固相包被的孕酮单克隆抗体,建立直接竞争ELISA反应体系.试验结果表明,最佳抗体包被浓度为1∶2 000,最佳酶标抗原工作浓度为1∶16 000,建立的标准曲线为y=-2.4598x+0.999(R2=0.996),牛奶中孕酮检测范围0.12～40 ng/mL,最低检测量为0.12 ng/mL,批内和批间变异系数分别为1.63%和2.49%.成功建立了可用于牛乳中孕酮快速检测的直接竞争ELISA方法. 相似文献
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本研究旨在探讨陕北白绒山羊毛囊外根鞘细胞的培养和VEGF对次级毛囊外根鞘细胞增殖、分化及细胞中增殖细胞核抗原(PCNA)、角蛋白10(K10)和成纤维细胞生长因子5(FGF5)mRNA表达量的影响。采集绒山羊体侧部皮肤,并利用消化等方法分离次级毛囊外根鞘细胞,置于37℃、5%CO_2、饱和湿度条件下培养;选用第5代次级毛囊外根鞘细胞,添加不同质量浓度血管内皮生长因子(VEGF),分别处理24、48h,噻唑兰比色法(MTT)检测细胞活力,EdU核酸标记技术检测细胞增殖;实时荧光定量PCR技术检测PCNA、K 10、FGF5mRNA的表达情况。结果显示:1)成功培养出次级毛囊外根鞘细胞,CK17和CK15细胞免疫组化呈阳性。2)VEGF可以促进绒山羊次级毛囊外根鞘细胞的增殖。相同浓度VEGF处理48h组的细胞活力极显著高于处理24h组(P0.01);在48h处理组中,100ng·mL~(-1)组的细胞活力极显著高于对照组、1ng·mL~(-1)组、10ng·mL~(-1)组(P0.01),并显著高于50ng·mL~(-1)组(P0.05),50ng·mL~(-1)组的细胞活力显著高于对照组(P0.05);100ng·mL~(-1)组和50ng·mL~(-1)组增殖细胞比例均极显著高于对照组、1ng·mL~(-1)组、10ng·mL~(-1)组(P0.01),100ng·mL~(-1)组显著高于50ng·mL~(-1)组(P0.05)。3)PCNA、K10、FGF5mRNA在次级毛囊外根鞘细胞中均有表达。在VEGF处理48h时,PCNA mRNA的表达量100ng·mL~(-1)组最高,极显著高于对照组(P0.01),显著高于10ng·mL~(-1)组(P0.05);K10mRNA的表达量对照组最高,极显著高于10ng·mL~(-1)组与100ng·mL~(-1)组(P0.01);FGF5mRNA的表达量对照组最高,极显著高于100ng·mL~(-1)组(P0.01)。综上表明,本研究成功分离培养了陕北白绒山羊次级毛囊外根鞘细胞;VEGF能够促进次级毛囊外根鞘细胞的增殖,抑制细胞的分化;VEGF可能通过抑制次级毛囊外根鞘细胞中FGF5基因的表达而促进毛囊生长。 相似文献
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鸡蛋和鸡肉中尼卡巴嗪残留检测高效液相色谱 串联质谱法研究 总被引：3，自引：2，他引：1
建立了鸡蛋和鸡肉中尼卡巴嗪残留标示物4,4'-二硝基碳酰替苯胺(DNC)检测的高效液相色谱-串联质谱方法(HPLC-MS/MS).液相色谱条件为色谱柱为XBridge C18柱(150 mm×2.1 mm,5 μm),流动相为甲醇 0.1 mol/L的乙酸铵水溶液(75 25,V/V),柱温30 ℃,流速0.2 mL/min,进样量20 μL.质谱条件为电喷雾离子源(ESI-),多反应监测(MRM)方式进行采集;DNC-D8同位素内标法定量.结果表明,DNC在10～500 ng/mL浓度范围内呈现良好的线性关系,R2为0.999 7;鸡蛋和鸡肉中DNC残留检测方法检测限均为0.5 ng/g,定量限均为1 ng/g;鸡蛋中从2、5和10 ng/g三个添加浓度检测结果可以看出,方法平均回收率为95.9%～102.2%,批内RSD为0.9%～4.4%,批间RSD为0.3%～2.1%.鸡肉组织从100、200和300 ng/g三个添加浓度检测结果可以看出,方法平均回收率为94.0%～103.3%,批内RSD为2.0%～6.3%,批间RSD为3.1%～5.2%. 相似文献
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《中国预防兽医学报》2020,(8)
为建立B型流感病毒(IBV)快速诊断方法,本研究采用真核表达系统表达并纯化了IBV中高度保守的核糖核蛋白(NP),以其为抗原,免疫小鼠制备IBV NP蛋白单克隆抗体(MAb),选取抗原表位长、特异性强的MAb2B3-5作为捕获抗体,选取抗原表位短、灵敏度高的MAb 3C3-7经HRP标记后作为检测抗体,经条件优化,建立了检测IBV NP蛋白的双MAb夹心ELISA检测方法。结果显示,该检测方法捕获抗体包被量为每孔100 ng,检测抗体使用量为每孔20 ng,NP蛋白浓度在3.9 ng/mL～62.5 ng/mL时与OD_(450nm)呈良好的线性关系,相关系数R20.99。利用该ELISA方法对多种病毒进行检测,结果显示该方法仅能与IBV发生反应,表明该方法特异性强;灵敏度试验结果显示,该方法对病毒NP蛋白的最低检测限为13.26 ng/mL,敏感性高;批内和批间重复性变异系数均小于8%,重复性好;捕获抗体可在25℃和37℃保存4 d,热稳定性好。利用本实验建立的ELISA方法和qPCR方法对本实验室保存的40份人咽拭子进行检测,该方法与qPCR方法相比符合率为70%,表明本研究建立的方法可用于临床检测。本研究建立的ELISA检测方法特异性强、灵敏度高、重复性好,为B型流感的快速诊断、NP蛋白功能研究及定量检测提供技术支持。 相似文献
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①目的:用高效液相色谱仪(HPLC)同时测定饲料中地西泮、安眠酮的含量。方法:在碱性条件下,用有机溶剂提取饲料中的地西泮和安眠酮,利用硅酸镁小柱对提取液进行富集、净化,用高效液相色谱仪进行检测。HPLC测定参数:C18柱(4.00mm×250mmi.d.,5μm);流动相乙腈—25mmol·L-1乙酸铵溶液(30:70);流速1.00mL·min-1;利用二极管阵列检测器测定地西泮、安眠酮紫外光区的特征光谱进行定性,外标法在254、226nm处进行定量。②结果:样品提取液中各组分分离良好,地西泮浓度在200ng·mL-1～100μg·mL-1范围内与峰面积呈线性相关,R=0.9992;平均回收率:92.28%～114.9%;变异系数(RSD)<5%;检测限(S/N=3)4ng。安眠酮浓度在250ng·ml-1～500μg·mL-1范围内与峰面积呈线性相关,R=0.9996;平均回收率:87.5%～112.9%;变异系数(RSD)<5%;检测限(S/N=3)1.2ng;其他常用镇静安眠药物在该条件下对地西泮、安眠酮均无干扰。③结论:是一种简便、快速、准确的方法。 相似文献
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Electroimmobilization and ovine plasma cortisol concentrations: effect of current intensity, current duration and diazepam 总被引：1，自引：0，他引：1
Whether the increases in plasma cortisol concentrations which are associated with electroimmobilization (E-IM) of conscious sheep are modified by current intensity, current duration or prior treatment with diazepam was assessed. Sheep were electroimmobilized at 30, 40 or 60 mA for one minute and at 40 mA for two or four minutes. After E-IM of one minute's duration, peak plasma cortisol concentrations occurred at 20 minutes and were 39.1 +/- 7.8 ng ml-1 at 0 mA (control), 56.7 +/- 9.6 ng ml-1 at 30 mA, 62.1 +/- 6.9 ng ml-1 at 40 mA and 78.4 +/- 3.2 ng ml-1 at 60 mA. Both the peak plasma cortisol concentrations and the integrated cortisol responses to E-Im were correlated with current intensity (P less than 0.01). The cortisol responses to E-Im at 40 mA for one, two and four minutes were not significantly different and the response to E-IM at 40 mA for one minute was not affected by the administration of diazepam (0.2 mg kg-1 intravenously) 15 minutes before E-IM. These results indicate that the cortisol response to E-IM is directly dependent on current intensity and that adrenocortical activation by E-IM may be minimised by choosing the lowest current at which effective restraint is maintained. 相似文献
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The present study was undertaken to examine whether beta-adrenergic blockade with propranolol might influence and make less variable the growth hormone (GH) response to exogenous GH releasing hormone (GHRH) 1-44 in the dog. On four separate occasions eight healthy beagles, one to two years old, randomly received either propranolol (40 micrograms kg-1 intravenously) or an equivalent volume of saline, 30 minutes before either GHRH 1-44 (1 microgram kg-1 intravenously) or vehicle was injected. After propranolol alone, GH secretion did not differ from saline (area under the curve [AUC]: 649.5 +/- 128.3 v 633.2 +/- 87.7 ng min ml-1, respectively). GHRH alone elicited a significant increase in GH secretion (AUC: 1230.5 +/- 210.5 ng min ml-1) with a peak concentration of 16.7 +/- 4.8 ng ml-1. When GHRH was injected after propranolol the mean peak (59.1 +/- 14.7 ng ml-1) and secretory area (AUC: 2631.0 +/- 474.4 ng min ml-1) were greater than those observed after GHRH alone. However, from a clinical point of view propranolol pretreatment does not modify the great individual variability of the GH response to GHRH. 相似文献
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Influence of arachidonic acid metabolites in vitro and in uterine washings on migration of equine neutrophils under agarose 总被引：1，自引：0，他引：1
The influence of arachidonic acid metabolites on migration of equine neutrophils under agarose was investigated. Leukotriene B4 (LTB4) was chemotactic at concentrations between 0.1 and 1000 ng ml-1 and prostaglandin E2 (PGE2) at 1 and 10 ng ml-1 but not at higher or lower concentrations. Prostaglandin F2 alpha (PGF2 alpha) was not chemotactic for equine neutrophils at any concentration. Random migration was significantly inhibited (P less than 0.05) by suspension of neutrophils in LTB4 (0.1 to 1000 ng ml-1) and PGF2 alpha (0.1 ng ml-1) but not at high concentrations. There was a significant positive correlation between random migration of neutrophils suspended in uterine washings from persistently endometritic mares and concentrations of endogenous PGF (P less than 0.002) and PGE2 (P less than 0.05) in washings. Thus certain metabolites of arachidonic acid affect migration of equine neutrophils and may play a significant role in recruitment of neutrophils to sites of inflammation in the horse. 相似文献
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采用超高效液相色谱-三重四级杆质谱(UPLC-MS/MS)建立厄贝沙坦及其复方制剂中N-亚硝基-N-甲基-4-氨基丁酸(NMBA)的测定方法。采用Waters ACQUITY UPLC○RHSS T3色谱柱进行分离,以0.005 mol/L甲酸铵(用甲酸调pH值至3.0)为流动相A,甲醇为流动相B,梯度洗脱,质谱检测器,流速为0.3 mL/min。结果显示NMBA的线性范围为0.156 6~3.132 6 ng/mL,相关系数r>0.99,方法检出限浓度为0.047 0 ng/mL(相当于样品浓度0.01μg/g),定量限浓度为0.156 6 ng/mL(相当于样品浓度0.03μg/g),样品加标回收率在80%~130%。说明该方法可以快速、简便、灵敏、准确地测定厄贝沙坦及其复方制剂中NMBA含量。 相似文献
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Dose response of two synthetic human growth hormone-releasing factors on growth hormone release in heifers and pigs 总被引：1，自引：0，他引：1
D Peticlerc G Pelletier H Lapierre P Gaudreau Y Couture P Dubreuil J Morisset P Brazeau 《Journal of animal science》1987,65(4):996-1005
This study was undertaken to evaluate the biological potency of two synthetic human growth hormone-releasing factors, hGRF (1-44)NH2 and hGRF (1-29)NH2, on growth hormone (GH) release in young dairy heifers (n = 10) and pigs (n = 10). In each species, the GH response to an iv injection (0, .067, .2, .6 and 1.8 nmol.kg-1 body weight) of each peptide was evaluated in a double 5 X 5 Latin square design. In each square, there were five animals injected with either hGRF (1-44)NH2 or hGRF (1-29)NH2. Main effects were doses (n = 5) of hGRF and days (n = 5) of injection. In both species, data indicated that hGRF (1-44)NH2 and hGRF (1-29)NH2 equally stimulate GH secretion at all doses. In dairy heifers, average peak concentrations (81.7, 94.7, 84.5 and 93.7 ng.ml-1 vs 91.5, 81.0, 94.3 and 91.6 ng.ml-1) and area under the GH response curve (3,661, 4,541, 7,196 and 6,788 ng.ml-1.min vs 3,000, 3,982, 5,639 and 6,724 ng.ml-1.min) were not different (P greater than .05) between hGRF(1-44)NH2 and hGRF(1-29)NH2 at .067, .2, .6 and 1.8 nmol.kg-1, respectively. Similarly, in pigs, average peak concentrations (35.6, 38.6, 76.5 and 73.8 ng.ml-1 vs 28.7, 30.0, 41.3 and 80.8 ng.ml-1) and area under the GH curve (1,576, 1,567, 3,299 and 3,622 ng.ml-1.min vs 1,115, 1,658, 1,482 and 2,528 ng.ml-1.min) were not different (P greater than .05) between both peptides. A biphasic release of GH after hGRF (1-44)NH2 and hGRH (1-29)NH2 injection was observed at the highest dose in heifers. The GH response to hGRF injection was much more variable in pigs as compared with dairy heifers. In conclusion, hGRF (1-44)NH2 and its (1-29)NH2 fragment are equipotent in stimulating GH release in dairy heifers and pigs. 相似文献
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S Binder M Beutel T Lindl 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1990,37(9):696-700
The examinations show, that it is possible to adapt MDBK-cells (ATCC CCL 22) to serum-poor (0.1% fetal calf serum) and to serum-free, adequate supplemented media. Morphology of the cells remained unchanged. The components of the serum-free medium are a 50:50 mixture of Dulbecco's modified Eagle's medium and HAM's F12 medium, supplemented with insulin (5 micrograms ml-1), transferrin (10 micrograms ml-1), thyroglobulin (10 micrograms ml-1), prostaglandin E1 (50-100 ng ml-1). Seeding cells at a density of 26.10(3) cm-2 at day 0 resulted in better multiplication than a higher seeding density. 相似文献
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In six heifers without sexual organs the effects were compared of the superanalogues LH-RH [(D-Tle6) and (D-Trp6)] on the secretion of luteinizing hormone (LH) and follicles of stimulating hormone (FSH). The superanalogues were given i. m. at dosages of 10, 50 and 100 micrograms pro toto. Dosages of 50 and 100 micrograms of both superanalogues had a greater effect on the secretion of LH than the dosage of 100 micrograms. The highest average concentration of LH during the time of application (D-Tle6) was recorded in the dosage of 10 micrograms (7.84 ng.ml-1). The average concentrations of LH after application (D-Trp6) were within the range of 5.46 to 9.29 ng.ml-1. Because of the great variability of the concentrations of LH no significant differences were ascertained due to the influence of dosage. From a comparison of the concentrations of LH with the same dosage it emerged that (D-Trp6) after an application of 50 micrograms significantly increased the concentration of LH from the 60th to the 240th minute and thus had a more protracted effect. With dosages of 10 and 100 micrograms of the superanalogues no statistically significant differences were recorded after two hours from application. With (D-Trp6) the higher stimulative effect on the secretion of LH was statistically confirmed. The highest concentrations of follicles of stimulation hormone (FSH) (204.6 and 228.6 ng.ml-1) were found from the 40th to the 100th minute after the application of dosages of 50 and 100 micrograms (D-Tle6). The protracted effect was greatest with a dosage of 100 micrograms (270 mins). (D-Trp6) at a dosage of 100 micrograms caused the greatest effect on the secretion of FSH (226.8 ng.ml-1 for a period of 180 mins). The lower dosages of analogues scarcely differed in response. The dosage of superanalogues has an influence on the concentration of FSH in peripheral blood and on the duration of the protracted effect. 相似文献
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A.T. Peter W.T.K. Bosu G.I. Perez G. Lord-Kujjo J.D. Gaines 《Research in veterinary science》1991,50(3):315-318
An experiment was conducted to measure the changes in serum cortisol and luteinising hormone (LH) concentrations in heifers during the luteal phase of the oestrous cycle after the administration of lipid X and Gram-negative endotoxin. Nine heifers whose oestrous cycles were synchronised with prostaglandin F2 alpha were assigned at random on day 10 after the second prostaglandin injection to one of the following groups. Group 1 heifers (n = 3) received 5 micrograms kg-1 bodyweight of Escherichia coli endotoxin as an intrauterine infusion and one hour later received an intravenous injection of lipid X (5 micrograms kg-1 bodyweight). The treatment was reversed in group 2 heifers (n = 3), endotoxin was administered one hour after the lipid X treatment. Group 3 heifers (n = 3) received endotoxin infusion and lipid X treatment at the same time. Similar dosages and routes of administration were used in all the groups for lipid X and endotoxin treatments. Blood samples were collected once every 15 minutes for seven hours, beginning once hour before and six hours after the initial treatment. In group 1 heifers there was a fourfold increase in serum cortisol concentrations within 30 minutes after both the treatments (from 6.5 to 24.6 ng ml-1 and from 7.3 to 29.5 ng ml-1 respectively). In group 2 heifers the cortisol concentrations increased from the baseline concentrations of 7.2 to 33.2 ng ml-1 within 30 minutes after lipid X treatment and remained at 22.5 ng ml-1 during endotoxin treatment. There was a further increase in cortisol concentrations (28.9 ng ml-1) after the endotoxin treatment.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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The suppressive effects of three different low dosages of dexamethasone (5, 10 and 15 micrograms kg-1) on serum cortisol concentrations were evaluated in 10 normal cats. On four different days, serum was collected before and at two, four, six and eight hours after the intravenous administration of saline or dexamethasone. Following the administration of saline, no significant difference in mean serum cortisol concentrations was noted between the basal or postinjection values. In contrast, mean serum cortisol concentrations decreased significantly (P less than 0.05) by two hours and remained significantly below mean basal values eight hours after injection of all three dosages of dexamethasone. The degree of cortisol suppression became progressively greater as the dosages of dexamethasone were increased. After administration of the highest dose of dexamethasone (15 micrograms kg-1), serum cortisol decreased to below 5 ng ml-1 by two to four hours and remained suppressed (under 5 ng ml-1) eight hours after injection in all cats. In contrast, two of the 10 cats showed a slight escape from cortisol suppression by eight hours after injection of dexamethasone at the dosage of 10 micrograms kg-1, whereas a dosage of 5 micrograms kg-1 failed to suppress cortisol concentrations below 10 ng ml-1 at any of the sampling times in one cat and was associated with increasing serum cortisol concentrations at eight hours after injection in three cats.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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The fluctuations in the concentrations of progesterone in peripheral blood of three intact coypus and three coypus after natural mating were investigated for the period of four months. Immediately after mating the concentrations of progesterone are low (1.5-2.4 ng.ml-1), the maximum values reach the peak between the 14th and 15th week of gravidity (12.50-20.72 ng.ml-1), whilst there is almost no change in the intact females. On the last days of gravidity the values of progesterone decrease rapidly and they are very low on the day of parturition (1.0-2.5 ng.ml-1). The concentration of progesterone in the blood plasma of intact females in the test period is low (0.09-3.18 ng.ml-1). 相似文献