Simultaneous steroids measurement in dogs with hyperadrenocorticism using a column-switching liquid chromatography-tandem mass spectrometry method

We developed an analytical method using an on-line column-switching liquid chromatography with triple quadrupole mass spectrometry (LC/MS/MS) for quantifying multiple steroids in serum. Using the developed method, we evaluated the serum concentration of nine steroids (cortisol, corticosterone, cortisone, 11-deoxycortisol, 21-deoxycortisol, deoxycorticosterone, progesterone, 17α-OH-progesterone and aldosterone) in dogs with hyperadrenocorticism (HAC). Serum was mixed with stable isotope internal standards and thereafter purified by the automated column-switching system. The limit of detection ranged 2–16 pg/ml for nine steroids. In the baseline samples, five steroids (cortisol, corticosterone, cortisone, 11-deoxycortisol, and 17α-OH-progesterone) were detected in all dogs. The concentrations of cortisone, 11-deoxycortisol, and 17α-OH-progesterone in dogs with HAC (n=19) were significantly higher those in dogs without HAC (n=15, P<0.02). After the adrenocorticotropic hormone stimulation test, six steroids (cortisol, corticosterone, cortisone, 11-deoxycortisol, 17α-OH-progesterone, and deoxycorticosterone) were above the limit of quantification in all dogs. Cortisol, corticosterone, cortisone, and deoxycorticosterone concentrations of dogs with HAC were significantly higher than those of dogs without HAC (P<0.02). In addition, 11-deoxycortisol and 17α-OH-progesterone concentration was higher in dogs with HAC than in dogs without HAC (P=0.044 and P=0.048, respectively). The on-line column-switching LC/MS/MS would be feasible for measuring multiple steroids in dog serum. The results suggest that cortisone, 11-deoxycortisol, and 17α-OH-progesterone would be related to HAC. Further studies are warranted to assess the clinical feasibility of steroid profile in dogs with HAC.     

液相色谱串联质谱法测定饲料中黄霉素A的含量

建立了液相色谱―串联质谱法测定饲料中黄霉素A含量的检测方法,样品中的黄霉素A经氨水甲醇提取,HLB柱净化后,以Agilent Ecillps C18色谱柱为分析柱,乙腈-10 mM的乙酸铵为流动相进行梯度洗脱,经液相色谱―串联四级杆质谱多反应监测（MRM）模式下检测。该方法黄霉素A的线性范围为100～5000 μg/L,相关系数（r）为0.999725。依据S/N≥10确定方法的定量限为100 μg/kg。添加浓度在100～1000 μg/kg时,回收率在75%～95%之间,相对标准偏差（RSD）在4.7%～6.4%之间（n=5）。     

Quantitative determination of 12-hydroxyeicosatetraenoic acids by chiral liquid chromatography tandem mass spectrometry in a murine atopic dermatitis model

Atopic dermatitis, one of the most important skin diseases, is characterized by both skin barrier impairment and immunological abnormalities. Although several studies have demonstrated the significant relationship between atopic dermatitis and immunological abnormalities, the role of hydroxyeicosatetraenoic acids (HETE) in atopic dermatitis remains unknown. To develop chiral methods for characterization of 12-HETE enantiomers in a 1-chloro-2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis mouse model and evaluate the effects of 12-HETE on atopic dermatitis, BALB/c mice were treated with either DNCB or acetone/olive oil (AOO) to induce atopic dermatitis, after which 12(R)- and 12(S)-HETEs in the plasma, skin, spleen, and lymph nodes were quantified by chiral liquid chromatography-tandem mass spectrometry. 12(R)- and 12(S)-HETEs in biological samples of DNCB-induced atopic dermatitis mice increased significantly compared with the AOO group, reflecting the involvement of 12(R)- and 12(S)-HETEs in atopic dermatitis. These findings indicate that 12(R)- and 12(S)-HETEs could be a useful guide for understanding the pathogenesis of atopic dermatitis.     

Sporozoite proteome analysis of Cryptosporidium parvum by one-dimensional SDS-PAGE and liquid chromatography tandem mass spectrometry

Despite the development of new technologies, new challenges still remain for large scale proteomic profiling when dealing with complex biological mixtures. Fractionation prior to liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis is usually the preferred method to reduce the complexity of any biological sample. In this study, a gel LC-MS/MS approach was used to explore the stage specific proteome of Cryptosporidium (C.) parvum. To accomplish this, the sporozoite protein of C. parvum was first fractionated using SDS-PAGE with subsequent LC-MS/MS analysis. A total of 135 protein hits were recorded from 20 gel slices (from same gel lane), with many hits occurring in more than one band. Excluding all non-Cryptosporidium entries and proteins with multiple hits, 33 separate C. parvum entries were identified during the study. The overall goal of this study was to reduce sample complexity by protein fractionation and increase the possibility of detecting proteins present in lower abundance in a complex protein mixture.     

高效液相色谱-串联质谱法测定熟制鸡肉制品中金刚烷胺

建立了高效液相色谱-串联质谱(HPLC-MS/MS)测定熟制鸡肉制品中金刚烷胺的分析方法。样品用乙腈提取,PXC小柱净化,经C18色谱柱分离,以电喷雾离子源(ESI)在正离子多反应监测(MRM)模式下进行测定,内标法定量。金刚烷胺的检出限为0.05μg/kg,定量限为0.15μg/kg,在0.3~150μg/L范围内线性关系良好,相关系数r2为0.9992。对于4种不同的熟制鸡肉制品,在4个加标水平下的平均回收率范围为87.2%~94.8%,批内精密度(n=6)为6.7%~10.0%,批间精密度(n=3)为8.5%~13.6%。该方法灵敏度高,准确性好,适用于熟制鸡肉制品中金刚烷胺残留量的测定。     

Prediction of vascular invasion using a 7‐point scale computed tomography grading system in adrenal tumors in dogs

BackgroundPrevious studies evaluating the accuracy of computed tomography (CT) in detecting caudal vena cava (CVC) invasion by adrenal tumors (AT) used a binary system and did not evaluate for other vessels.ObjectiveTest a 7‐point scale CT grading system for accuracy in predicting vascular invasion and for repeatability among radiologists. Build a decision tree based on CT criteria to predict tumor type.MethodsRetrospective observational cross‐sectional case study. Abdominal CT studies were analyzed by 3 radiologists using a 7‐point CT grading scale for vascular invasion and by 1 radiologist for CT features of AT.AnimalsDogs with AT that underwent adrenalectomy and had pre‐ and postcontrast CT.ResultsNinety‐one dogs; 45 adrenocortical carcinomas (50%), 36 pheochromocytomas (40%), 9 adrenocortical adenomas (10%) and 1 unknown tumor. Carcinoma and pheochromocytoma differed in pre‐ and postcontrast attenuation, contralateral adrenal size, tumor thrombus short‐ and long‐axis, and tumor and thrombus mineralization. A decision tree was built based on these differences. Adenoma and malignant tumors differed in contour irregularity. Probability of vascular invasion was dependent on CT grading scale, and a large equivocal zone existed between 3 and 6 scores, lowering CT accuracy to detect vascular invasion. Radiologists'' agreement for detecting abnormalities (evaluated by chance‐corrected weighted kappa statistics) was excellent for CVC and good to moderate for other vessels. The quality of postcontrast CT study had a negative impact on radiologists'' performance and agreement.Conclusions and Clinical ImportanceFeatures of CT may help radiologists predict AT type and provide probabilistic information on vascular invasion.     

高效液相色谱-串联质谱法同时测定水产品中残留的12种喹诺酮和磺胺类药物

建立水产品中有12种喹诺酮类（QNs）和磺胺类（SAs）药物残留量同时测定的高效液相色谱-串联质谱方法。以氘代试剂做内标,选择乙腈提取,用正己烷脱脂,旋转蒸发浓缩,采用LC—MS／MS选择反应监测（SRM）正离子模式测定进行定性、定量分析。结果表明,12种喹诺酮类（QNs）和磺胺类（SAs）药物的检出限（LOD）为1．0μg／kg,定量限（LOQ）为2．0μg／kg,检测结果的相对标准偏差为3．5％～14．6％（n=6）,加标回收率达到69．5％～121．9％。该方法具有比较高的重现性和选择性,在水产品中喹诺酮类和磺胺类药物的残留测定中具有很好的应用前景。     

超高效液相色谱-串联质谱法测定原料乳中苯并咪唑类药物

建立了超高效液相色谱—串联四级杆质谱法测定原料奶中苯并咪唑类药物残留量的检测方法。原料奶经乙酸乙酯提取,MCX固相萃取柱净化,用UPLC-MS/MS进行检测。色谱条件为：色谱柱为ACQUITYUPLCTMBEHC18柱（2.1 mm×100 mm,1.7μm）;流动相为：乙腈-0.1%甲酸水溶液,梯度洗脱,流速为0.3 mL/min。采用ESI正离子模式,多反应监测（MRM）模式检测,外标法定量。本方法检测测苯并咪唑类药物残留的检测限为0.5μg/kg,定量限为1.0μg/kg。     

超高效液相色谱-串联质谱法测定鸡蛋中氯霉素的两种前处理方法比较

为选择氯霉素超高效液相色谱串联质谱分析前处理方法,分别对乙酸乙酯提取,正己烷液液萃取净化和乙腈提取,LC-Si固相萃取柱萃取净化(GB/T22338-2008方法),两种前处理方法进行对比分析。结果显示:乙酸乙酯提取法的检测限为0.1μg/kg,在0.5~10ng/mL范围内线性关系良好,r>0.99,回收率为98.2%~104.8%,RSD为1.5%~7.2%;乙腈提取法的检测限为0.05μg/kg,在0.25~10ng/mL范围内线性关系良好,r>0.995,回收率为100.0%~104.0%%,RSD值为0.5%~2.1%。结果表明:两种方法的线性范围、回收率、检测限和相对偏差均能满足畜产品检验要求。乙酸乙酯提取法步骤简单,样品处理效率高,乙腈提取法虽步骤繁琐,但结果的精密度和灵敏度更高。     

超高效液相色谱-二极管阵列-四极杆静电轨道阱质谱法对杆菌肽组分的分析

开发建立了超高效液相色谱-二极管阵列-串联四级杆静电场轨道阱高分辨质谱联用分析杆菌肽组分的方法。采用(Phenomenex C₁₈100 mm×3.0 mm,2.6μm)色谱柱,以0.1%甲酸溶液-0.1%甲酸甲醇乙腈(75+25)溶液为流动相,0.3 mL/min线性梯度洗脱分离,紫外吸收波长为254 nm。采集杆菌肽各组分质谱母离子及其对应子离子,并进行解析,推测组分的结构。在所建立的条件下,检测出9个组分,杆菌肽各组分之间分离良好。利用紫外与质谱归一化法测定含量,两种结果相对偏差在0.01%~3.53%之间。建立的超高效液相色谱-二极管阵列-串联四级杆静电场轨道阱高分辨质谱法能有效分析多肽类药物杆菌肽各组成成分,为杆菌肽的质量控制和工艺优化提供了参考。     

超高效液相色谱串联高分辨四极杆飞行时间质谱法快速筛选鉴别猪血浆中的大环内酯类抗生素

采用超高效液相色谱串联高分辨四极杆飞行时间质谱法(UPLC-Q-TOP-MS)结合大环内酯类抗生素数据库,建立快速筛查鉴别猪血浆中常见大环内酯类抗生素的方法。猪血浆经甲醇提取,通过UPLC-Q-TOP-MS正离子模式全扫描分析,采用Agilent Extend-C18色谱柱(50×2.1 mm,1.8μm)分离,以乙腈-2 mmol/L乙酸铵水溶液(含0.1%甲酸)为流动相梯度洗脱,流速0.4 m L/min,柱温40℃,得到猪血浆中大环内酯类抗生素准分子离子峰精确质量数、主要碎片峰的精确质量数和保留时间后,结合大环内酯类抗生素数据库筛查,实现猪血浆中大环内酯类抗生素的快速定性识别。所建数据库包含26种常见猪血浆中大环内酯类抗生素的准分子离子峰精确质量数、主要碎片峰的精确质量数和保留时间,其中13种常见大环内酯类抗生素的检测限在1.00~8.00ng/g范围内。该方法分离度高、检测灵敏,可以作为快速筛查鉴别猪血浆中大环内酯类抗生素的有效方法。     

Identification and preservation of the parathyroid gland during total thyroidectomy in dogs with bilateral thyroid carcinoma: a report of six cases

Simultaneous removal of bilateral thyroid tumors was performed while preserving the parathyroid gland in six dogs. At least one external parathyroid gland was identified in all dogs. In five cases, the external parathyroid gland and its blood supply were preserved intact. In one dog, the vessels supplying the external parathyroid gland had been invaded by the tumor, and the gland was thus removed and reimplanted into the sternohyoid muscle. That dog required postoperative treatment with oral calcium gluconate and vitamin D₃. Local tumor recurrence was not observed in any of the cases. The mean survival time was 920 days. We found that the external parathyroid gland could be identified and preserved in most dogs undergoing total thyroidectomy.