Validation of human recombinant tissue factor-activated thromboelastography on citrated whole blood from clinically healthy dogs

BACKGROUND: Thromboelastography (TEG) is an analytical method that enables global assessment of hemostatic function in whole blood (WB) with evaluation of both plasma and cellular components of hemostasis. TEG has a largely unused potential in the diagnostic workup and monitoring of dogs with hemostatic disorders and it may be a valuable supplement to traditional coagulation parameters. OBJECTIVES: The objective of this study was to establish a clinically applicable reference interval for a TEG assay using recombinant human tissue factor (TF) as the activator on citrated WB from clinically healthy dogs and to evaluate the stability of citrated WB stored for 30 minutes (T30) and 120 minutes (T120) at room temperature (RT). Additionally, we evaluated the analytical variation in reaction time (R), clotting time (K), angle (alpha), and maximum amplitude (MA). METHODS: Blood was collected from 18 clinically healthy dogs. Duplicate TEG analyses with TF as the activator at a concentration of 1:50,000 were performed on canine citrated WB at T30 and T120. R, K, a, and MAwere analyzed. RESULTS: Mean TEG values at T30/T120 were R = 5.61/4.91 minutes, K = 4.20/3.34 minutes, alpha = 45.33/50.90 degrees , and MA = 47.96/50.19 mm. Significant differences in these values were observed after storage for T30 and T120 at RT, with a tendency towards hypercoagulability at T120. The mean coefficients of variation were low. CONCLUSIONS: Canine citrated WB can be used for TEG analysis with human recombinant TF as the activator when stored at RT for T30 or T120. At both time points, the analytical variation was low, suggesting that TEG analysis may be of value in evaluating dogs with hemostatic disorders. A fixed time point should be chosen for serial measurements.     

The role of tissue factor and tissue factor pathway inhibitor in health and disease states

Objective – To review the veterinary and human literature on the role of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in health and disease states.
Data Sources – Original research articles and scientific reviews from both human and veterinary literature were searched for relevance to TF and TFPI.
Human Data Synthesis – Interest in both TF and TFPI has grown widely over the last several years. The impact TF plays in coagulation, inflammation, angiogenesis, tumor metastasis, and cellular signaling has become apparent. Treatment with TFPI for severe sepsis has been examined and is still currently under investigation. Inhibition of the TF pathway is being studied as an aid in the treatment of neoplasia. The important physiologic and pathophysiologic role these molecules play has only begun to be understood.
Veterinary Data Synthesis – There is a paucity of publications that discuss the importance of TF and TFPI in veterinary medicine. An enhanced understanding of the TF pathway in human medicine, in experimental animal models treating sepsis with TFPI, and in animal models demonstrating the proangiogenic properties of TF provides relevance to veterinary medicine.
Conclusion – It is apparent that TF and TFPI are important in health and disease. An enhanced understanding of the physiologic and pathophysiologic roles of these factors provides better insight into coagulation, inflammation, angiogenesis, disseminated intravascular coagulation, and tumor metastasis. This greater understanding may provide for the development of therapeutics for sepsis, disseminated intravascular coagulation, and neoplasia.     

Expression of tissue factor in experimental bovine pneumonic pasteurellosis and endotoxemia

Tissue factor (TF), a cell surface-associated cofactor and activator of coagulation factor VII, has been implicated in the local and systemic activation of coagulation associated with sepsis. This study describes the pattern of TF expression in experimental bovine pneumonic pasteurellosis and endotoxemia. Immunohistochemical techniques were used to localize TF antigen in tissue sections. Tissue factor expression was not observed in tissues from control animals. In response to Pasteurella haemolytica challenge, TF was expressed within alveolar walls, by mononuclear inflammatory cells within alveoli, and in walls of arteries, arterioles, bronchi, and bronchioles. Tissue factor was not detected in unaffected lung, liver, spleen, lymph node or kidney tissue. Administration of Escherichia coli endotoxin intravenously resulted in tissue factor expression in lung, spleen, and lymph node tissue. Results of this study indicate that TF is expressed locally at sites of inflammation and systemically in endotoxemia. Therefore, TF may be involved in coagulation events associated with pneumonic pasteurellosis.     

Effects of storage time and freezing temperature on clinical chemical parameters from canine serum and heparinized plasma

To assess changes in 24 blood constituents in frozen serum and heparinized plasma, blood samples were drawn from 10 clinically normal German Shepherd army dogs. The storage characteristics of nine enzymes (ALP, ALT, amylase, AST, CK, GGT, GLDH, LDH, lipase), and 15 metabolites and minerals (albumin, bile acids, bilirubin, calcium, cholesterol, creatinine, fructosamine, glucose, magnesium, phosphate, potassium, protein, sodium, triglycerides, urea) were studied. Parallel samples of serum and heparinized plasma were stored for 90 and 240 days at two different storage temperatures, -200 degrees C and -700 degrees C. Sixteen of the 24 analytes (ALP, ALT, amylase, AST, CK, GGT, GLDH, LDH, bile acids, calcium, cholesterol, creatinine, fructosamine, magnesium, phosphate, urea) showed statistically significant (p < 0.05) changes during the storage period related to storage time, storage temperature, and sample type. Seven of the analytes (amylase, GGT, GLDH, LDH, bile acids, fructosamine, magnesium) showed changes of possible clinical importance with mean differences from baseline larger than 20% for the enzymes and 10% for the metabolites and minerals during the storage periods.     

A clinical study of plasminogen activator activity in gingival tissue in dogs with gingivitis and periodontitis

The aim of the present study was to evaluate plasminogen activator activity (PAA), tissue-type plasminogen activator (t-PA) antigen level and plasminogen activator inhibitor-1 (PAI-1) antigen in normal canine gingival tissue samples, gingivitis as well as in different stages of periodontal disease. Gingival tissue from 141 adult dogs were analysed spectrophotometrically in order to determine PAA. The tissues were also examined histopathologically. The Sulcus Bleeding Index was used to evaluate the active and inactive phase of periodontal disease. T-PA antigen as well as PAI-1 antigen level was measured by ELISA. There was a significant increase of PAA and t-PA antigen in samples from inflamed gingival tissue compared with normal gingival tissue, while PAI-1 antigen was not detected in either normal or inflamed gingiva. As the severity of periodontal disease was increasing, PAA and t-PA antigen values were significantly higher in periodontitis tissue sample groups, according to the pattern: gingivitismoderate bleeding>slight bleeding, P<0.001). In conclusion, this study indicates that PAA and t-PA antigen level may be used to evaluate the evolution of periodontal disease in dog.     

不同储藏方式对鸡蛋品质的影响

 为探讨夏季常温保存和低温冷藏两种储藏方式对鸡蛋品质的影响,选择540个鸡蛋随机分为9组,1组当天测定蛋品质,3组置于28.31 ℃、湿度为68.13%的室温下保存,5组置于4~8 ℃的冷藏室保存,分别于第7、14、21、42和56 d测定蛋品质。结果表明,常温储藏的鸡蛋随着存放时间延长,鸡蛋品质不断下降,储藏21 d后,蛋重降低5.30%（P<0.05）,蛋壳厚度变薄（P<0.05）;哈氏单位随着储藏时间的延长迅速下降,第0 d比第21 d的哈氏单位值高59.18%（P<0.05）;蛋黄比率随储藏时间的延长有不断变大的趋势,第0 d的蛋黄比率比第21 d低15.58%（P<0.05）。低温冷藏的鸡蛋储藏到21 d时,仅哈氏单位比第0 d低6.78%（P<0.05）;冷藏到56 d时,蛋重和哈氏单位比第0 d分别降低5.63%和15.07%（P<0.05）,蛋黄比率提高了5.21%（P<0.05）。试验表明,鸡蛋在室温下的新鲜度适宜保存期不应超过21 d;低温冷藏时可以保存到56 d。     

Evaluation of a modified thrombelastography assay initiated with recombinant human tissue factor in clinically healthy horses

Background: Thrombelastography (TEG) is used to evaluate the viscoelastic properties of blood during clotting and provides a global assessment of hemostasis and clot lysis. TEG analysis initiated with recombinant human tissue factor (TF) has not been evaluated in clinically healthy horses. Objectives: The purpose of this study was to determine whether TEG results are affected by the time elapsed between sampling and analysis (storage time) of equine blood samples and to establish a preliminary equine reference interval for a modified TEG assay, using recombinant human TF to initiate coagulation. Methods: Citrated blood samples were obtained from 20 clinically healthy adult horses. Thirteen samples were stored for 30, 60, and 120 minutes at room temperature before TEG analysis. Coagulation was initiated by adding 20 μL of CaCl₂ to 330 μL of blood and 10 μL of diluted recombinant TF for a final dilution of 1:3600. Reaction (R) and clotting (K) times, angle (α), and maximum amplitude (MA) were compared between time points. A preliminary reference interval (minimum–maximum values) was determined using data from all 20 horses after 30 minutes of sample storage. Results: There was a significant effect of storage time on R, K, and α but not MA. Reference intervals were: R, 3.65–6.4 minutes; K, 1.8–5.45 minutes; α, 33.4–66.2°; MA, 41.2–64.1 mm; lysis at 30 minutes post‐MA (LY30), <2.75%; and lysis at 60 minutes post‐MA (LY60), 1.55–9.5%. Conclusions: TEG can be performed on equine citrated blood samples using recombinant human TF to activate clot formation. TEG parameters were significantly affected by storage time, suggesting an incomplete inhibition of coagulation in citrated blood.     

标准物质在兽医生物制品质量控制中的应用状况分析

探讨了兽医生物制品标准物质的概念及其在生物制品质量控制中的应用状况,分析了我国现阶段兽医生物制品标准物质供应和使用中存在的问题。建议进一步明确有关概念,形成共识,建立科学的兽医生物制品标准体系,分清各有关单位在标准物质供应工作中的责任,努力形成合力共同推进我国兽医生物制品标准物质工作进步。     

Effects of moisture content in quail litter on the physical characteristics after pelleting using a Siriwan Model machine

Quail litter (QL), a combination of accumulated quail manures, feathers, spilled feed and bedding materials, is a potential plant fertilizer, ruminant feed ingredient and other value‐added applications. In general, utilization of this litter has been limited to within a few kilometers of quail farms, because it has low density. Pelleting is one possible way to enhance storage, transportation and off‐site utilization. The purposes of this study were to show the procedures of pelleting and determine the effects of moisture content in fresh QL on the values of physical characteristics. Results obtained showed that bulk and particle densities of QL pellets decreased and increased, respectively, with an increase in moisture content. Porosity, durability, rupture force and decomposition were also affected by moisture content. Pelleting increased the bulk density of QL. Thus, this method more economically transported the litter from the quail farm to distant areas.     

Internal quality control of a turbidimetric immunoassay for canine serum C-reactive protein based on pooled patient samples

BACKGROUND: Optimized internal quality control (IQC) procedures are important to ensure that only results without medically important errors are used for medical decision-making and to ensure that unnecessary rejection of valid analytical runs is avoided. Additionally, estimates of the analytical performance can be derived from IQC data. In the absence of available species-specific standards of a compound, the use of alternative control materials based on patient samples is a possibility, although investigations on the suitability of this approach are needed. OBJECTIVES: The objective of the study was to plan and implement a simple IQC procedure with control material based on pooled canine serum samples for a turbidimetric immunoassay (TIA) for the determination of human C-reactive protein (CRP) that recently was validated for the determination of canine serum CRP, and to assess the clinical analytical performance of the assay. METHODS: Proposed guidelines for the planning and implementation of IQC procedures were followed by using 2 control materials. Quality requirements of the assay were defined objectively by means of available data on biological variation, and goals for IQC performance were defined according to recommendations (probability of error detection [P(ed)] >.90 and of false rejection [P(fr)] <.05). Analytical performance was evaluated by means of medical decision charts. RESULTS: The control rule of 1(2.5s) (ie, rejection of the analytical run if at least 1 of 2 control materials deviates from the mean by more than 2.5 SD) fulfilled the criteria of predicted IQC performance (P(ed) =.94-1.00, P(fr) =.03). The IQC method was successfully implemented over a 14-week period. The observed coefficient of variation in the period of monitoring was 3.8% (low) and 2.9% (high), which equals excellent analytical performance. CONCLUSIONS: It was possible to plan and implement a simple IQC procedure for the CRP-TIA with control materials based on canine serum samples that fulfilled the criteria of high error detection and low false rejection of valid analytical runs. The assay showed excellent long-term analytical performance over a 14-week period.     

Evaluation of a chromogenic assay to measure the factor Xa inhibitory activity of unfractionated heparin in canine plasma

BACKGROUND: Unfractionated heparin (UFH) has a complex pharmacologic profile that necessitates patient monitoring to prevent inadequate anticoagulation or overdosage and hemorrhage. Factor Xa inhibitory assays (to measure anti-Xa activity) are used to adjust UFH dosage and define safe and effective regimens for specific thrombotic disorders in humans. OBJECTIVE: In this study, the accuracy, linearity, and clinical utility of a chromogenic assay were assessed for monitoring UFH anti-Xa activity in canine plasma samples. METHODS: A commercial assay (Rotachrom Heparin, Diagnostica Stago, Parsippany, NJ, USA) was used to measure anti-Xa activity in canine plasma samples spiked with different concentrations of UFH. Background absorbance and assay linearity were compared for canine and human plasmas. Percentage recovery of UFH anti-Xa activity and intra- and interassay imprecisions were investigated by multiple measurements of canine plasma to which known amounts of UFH were added. The spiked plasma samples also were used to determine the heparin sensitivity of an activated partial thromboplastin time (aPTT) test. RESULTS: Canine plasma samples were assayed at a higher dilution than were human plasma samples (3:8 versus 4:8) to eliminate higher background anti-Xa activity in canine plasma. Using this modification, the recovery of anti-Xa activity in canine plasma was linear (R2 > .9) at concentrations of 0 - 0.75 U/mL UFH. Intra- and interassay imprecisions for plasma samples containing 0.5 U/mL UFH were <10%, whereas samples containing 0.25 U/mL UFH had imprecisions of 13% and 24%, respectively. The anti-Xa activity range of 0.5 - 0.75 U/mL caused prolongation of aPTTs to 1.5 - 2.5 times the assay mean. CONCLUSION: Plasma anti-Xa activity of dogs treated with UFH can be accurately monitored using this commercially available chromogenic assay.     

几种药剂对脐橙储藏期病害的防治效果比较研究

用7组药剂分别对纽荷尔脐橙做浸果处理,处理至135天,结果显示：百可得 咪鲜胺处理组烂果率7.78%,病情指数4.81,防效75.5%;咪鲜胺处理组烂果率13.33%,病情指数8.52,防效56.6%;百可得 抑霉唑处理组烂果率14.44%,病情指数8.15,防效58.48%;清水处理组烂果率30%,病情指数19.63。百可得 咪鲜胺处理组储藏效果最好,其次是咪鲜胺处理组和百可得 抑霉唑处理组。在脐橙的储藏保鲜中推荐使用百可得与咪鲜胺或抑霉唑混配或咪鲜胺单剂。