Heparin monitoring in sheep by activated partial thromboplastin time

Heparin anticoagulation is utilized during and after vascular surgery in animals to reduce the risk of acute or chronic thromboembolic problems. In this study, we examined variation of activated partial thromboplastin time APTT) after the intravenous bolus IV bolus) and subcutaneous SC) heparin injection in order to monitor heparin therapy in sheep. Nine healthy sheep were assigned to 3 groups A, B, and C) according to their body weights: less than 40 kg, 40 to 80 kg, and more than 80 kg, respectively. All animals were treated with heparin 300 IU/kg body weight) through two routes, and the APTT, fibrinogen, and platelet count were measured before and every hour after treatment. This showed that the APTT was increased significantly between 1 to 4 hours after IV bolus injection and between 2 to 6 hours after SC injection P < 0.05). The APTT was returned to baseline values 6 and 10 hours after the respective treatments. The APTT in Group C was consistently higher than in Group A and B after heparin treatment by the two routes. The APTT ratio entered the subtherapeutic range 5 and 8 hours after IV bolus and SC injection, respectively. The APTT ratio was maintained in the therapeutic range for about 1 and 4 hours after IV bolus and SC injection, respectively. The highest APTT ratio in Group C after SC injection of heparin was significantly higher than that in Groups A and B P < 0.05). The mean platelet counts in Groups A, B, and C before the injection were 3197 +/- 365.6, 2886 +/- 78.2, and 1861 +/- 298.0 102/microL, respectively. The mean platelet count gradually decreased without significant variation after IV bolus and SC injection. These results produced elementary data for monitoring in sheep using APTT, and suggested that heparin should be administrated by the SC route at 4-hour intervals in order to remain in the therapeutic range, after an initial IV bolus dose.     

Correlation between activated partial thromboplastin time and anti‐Xa activity in patients who received low‐molecular weight heparin as anticoagulation for haemodialysis

Plasma anti‐Xa activity, the recommended test to monitor low‐molecular weight heparin (LMWH) therapy, is not readily available in many laboratories. In our clinical trials on the use of LMWH as anticoagulation for haemodialysis, a consistent prolongation of APTT in addition to the elevated anti‐Xa activity was observed in the patients after LMWH administration. Hence, the paired anti‐Xa activity and APTT data were re‐analyzed. The APTT ratio, which was the proportional change in APTT from the baseline value after LMWH administration, was found to have a strong correlation with anti‐Xa activity (coefficient of determination, R ² = 0.72, P < 0.001). In the receiver operating characteristic analysis, the APTT ratio was also found to be an excellent predictor of therapeutic anti‐Xa activity ≧0.5 IU/mL (area under curve = 0.93, P < 0.001). The sensitivity was 88% and the specificity was 83.3% when an APTT ratio ≧1.4 was used as the cut point to predict the achievement of therapeutic anti‐Xa activity. Our results illustrated that APTT is a potentially useful screening test to assess the degree of anticoagulation achieved by LMWH during haemodialysis, if the testing for plasma anti‐Xa activity is not available.     

Bedside testing with the new CoaguChek Pro activated clotting time assay in dialysis

The objective of this study was to assess the analytical performance of CoaguChek Pro activated clotting time (ACT) assay using 2 lots versus Hemochron Celite and glass ACT regarding ACT values and correlations versus heparin levels. Determinations were performed using 4 CoaguChek Pro meters and 1 Hemochron 801 meter. Samples were collected during hemodialysis before, after start of heparinization, and 2 h later. Agreement between CoaguChek Pro ACT and Hemochron Celite was good (r = 0.82, slope = 1.12) and moderate with Hemochron glass (r = 0.83, slope = 0.97). Agreement between both CoaguChek Pro lots was r = 0.98. Agreement between the activators, Hemochron Celite, and glass was r = 0.73. Correlation between CoaguChek Pro ACT and heparin concentration was r = 0.88 and 0.94; for Hemochron the correlation was r = 0.75 (Celite) and r = 0.73 (glass). CoaguChek Pro ACT is therefore suitable for monitoring heparin administration during dialysis.     

Comparison of five point-of-care prothrombin and activated partial thromboplastin time devices based on age of blood sample

Delays in processing statium (STAT) blood samples have led to the production of an increasing number of point-of-care tests. Product inserts recommend measuring blood samples immediately after procurement, suggesting that delays may invalidate the test results. We studied the effect of the age of blood samples on point-of-care (POC) prothrombin time (PT) and an activated partial thromboplastin time (aPTT) result. Informed consent was obtained from 11 patients undergoing cardiopulmonary bypass (CPB). Blood samples (40 mL) were taken from each patient. Each blood sample was used to perform five PT tests and six aPTT tests on five POC devices (Gem PCL, Hemochron 801, Hemochron Jr. Signature, Hemochron Response, Rapidpoint Coag) at three different sample ages [< 60 s (fresh blood), 10 and 18 min after sample collection]. Blood samples were procured in a plastic syringe devoid of air bubbles, which was left undisturbed between tests but was gently agitated before initiating the 10- and 18-min tests. For tests requiring citrated whole blood, a fraction of each sample was anticoagulated (3.8% citrate) at each age. Statistical analysis was used for comparison of test results for fresh blood to aged samples (10 and 18 min). Test values were recorded as International Normalized Ratio (INR) and seconds for PT and aPTT, respectively. Two devices, the Hemochron 801 and Hemochron response showed statistically, although not clinically, significant variation in PT test results when the samples were aged to 10 and 18 minutes. As for aPTT results, Hemochron 801, Hemochron response, Hemochron Jr. signature, and Gem PCL showed statistically significant variation at 18 minutes. One device (Hemochron 801) reported results with 10-min aged blood that were statistically different from fresh blood. None of the aPTT tests results from any device produced results with aged blood that were clinically different from fresh blood. This study suggests that, in the tests evaluated, blood samples that have aged 10 or 18 min will produce clinically relevant aPTT and PT results, respectively.     

Intraoperative measurement of graft blood flow — a necessity in liver transplantation

Portal venous and hepatic arterial flow was measured intraoperatively in the 70 most recent patients undergoing liver transplantation in our institution. Impaired graft flow due to vascular abnormalities was detected in six patients. One patient suffered from arterial steal due to stenosis of the recipient celiac trunk with blood shunting from the hepatic to the splenic artery. Ligation of the recipient hepatic artery restored the arterial graft flow. In two patients we found reduced portal venous flow due to large portosystemic collaterals. The collaterals accountable for the impaired portal flow were identified and ligated, which restored portal venous graft flow. Excessive sensitivity of the portal venous flow to the position of the graft was found in a 6-month-old boy. Portal venous flow varied considerably, depending upon the position of the graft, and intraoperative flow measurement allowed the best position of the graft to be identified. Two patients developed arterial thrombosis in the early postoperative course. Immediate laparatomy with thrombectomy resulted in good, palpable pulsation in the graft artery in both patients. Intraoperative flow measurement demonstrated satisfactory arterial flow in one patient, whereas there was no net flow in the other patient's graft artery. Pulsation in this patient was caused by blood oscillating in and out of the liver. In conclusion, we find that causes of primary graft dysfunction due to technically flawed reperfusion of the graft can be identified and alleviated by intraoperative measurement of the flow in the graft vessels.     

外科病人术前凝血指标异常的临床意义及对策

外科病人术前合并凝血机制障碍时,围手术期处理较为复杂。在术前凝血机制筛查指标中,PT和APTT对术前病人凝血机制状态的评估更具有实际意义。外科医生对术前筛查凝血指标异常的处理程序可能并不熟悉。应综合分析可能影响凝血指标的相关因素及系统性疾病,根据不同的异常指标,进行相应的处理。     

Comparison of a new neuromuscular transmission monitor compressomyograph with mechanomyograph

BACKGROUND: We developed a new neuromuscular transmission monitor, the compressomyograph (CMG, European patent number: EP 06018557.6, US patent number: US 60/824.541). This is the first preliminary report comparing neuromuscular block monitored by CMG and the Relaxometer mechanomyograph (MMG). METHODS: The two monitors were randomly allocated to the left or right hands of 16 patients. T1, first twitch of the train-of-four (TOF) expressed as percentage of control response, and the TOF ratio (T4:t1) were used to evaluate the neuromuscular block produced by rocuronium 0.6 mg kg(-1). RESULTS: The CMG monitor exhibited no pre-relaxation reverse fade (T4>T1) or T1 exceeding 100%. There was no significant difference in mean (SD) onset time, Dur(25) (time to T1 25% recovery), or Dur(0.9) (time to 0.9 TOF ratio recovery) measured by the CMG [2.4 (0.9), 22.6 (4.1), 43.1 (10.3) min, respectively] compared with MMG [2.1 (0.9), 22.9 (3.3), 43.3 (10.0) min, respectively]. According to Bland and Altman analysis, the bias (upper and lower limits of agreement) for T1% was -0.3% (+13.4% and -13.8%) and for TOF ratio was -0.009 (+0.068 and -0.085). CMG showed 100% sensitivity and 75% specificity in indicating full relaxation for tracheal intubation, and 80% sensitivity with 86% specificity in predicting MMG 0.9 TOF ratio. CONCLUSIONS: The CMG could be a reliable clinical monitor in the daily anaesthesia practice that does not require time to set up or rigid support of the arm.     

Effect of heparin, platelets, activated platelets, platelet fragments, and hematocrit on activated clotting time

Activated clotting time (ACT) is the most commonly used laboratory test to control the heparin effect during extracorporeal techniques. The study was undertaken in order to test in vitro the influence of heparin, platelet count, hematocrit, platelet fragmentation, and platelet activation on ACT. Blood was drawn from volunteer donors into syringes containing citrate. Platelet counts and hematocrit were modified. Platelets were fragmented by sonifier or activated by collagen and adenosine diphosphate (ADP). Different heparin final concentrations were created. Increasing concentrations of heparin had a significant effect on ACT. However, it was not predictable in every case in concentrations lower than 1.0 U/ml. Platelet count generally had no significant effect on ACT. The effect of hematocrit was detectable in a group but not in single cases. Fragmented platelets significantly shortened ACT only without addition of heparin, and the effect was only partly predictable. Activation of platelets by collagen and ADP induced no significant changes. Our results show that heparin is reflected by ACT but that effect is not predictable in every specific patient. Our results also show that other variables that may be altered during extracorporeal techniques such as platelet count, hematocrit, activation, and fragmentation of platelets do not severely influence the ACT.     

Evaluation of corrected flow time in oesophageal Doppler as a predictor of fluid responsiveness

Background: Corrected flow time (FTc) by oesophageal Doppler is consideredto be a ‘static’ preload index. We evaluated theability of FTc to predict fluid responsiveness and comparedthis with the abilities of other preload indices, such as pulsepressure variation (PPV), central venous pressure (CVP), andleft ventricular end-diastolic area index (LVEDAI). Methods: Twenty neurosurgical patients were studied. After inductionof anaesthesia, FTc, PPV, LVEDAI, CVP, and stroke volume index(SVI) were measured before and 12 min after fluid loading with6% hydroxyethyl starch solution (7 ml kg^–1). Respondersand non-responders were defined as those patients with an SVIincrease 10% or < 10% after fluid loading, respectively.Pearson's correlation was used to assess correlations betweenchanges in SVI and initial haemodynamic variables. Receiveroperating characteristic (ROC) curves were constructed and comparedto evaluate the overall performance of preload indices (FTc,PPV, LVEDAI, and CVP) in terms of predicting fluid responsiveness. Results: FTc and PPV before fluid loading differed between responders(n = 11) and non-responders (n = 9), and correlated with changesin SVI (r = –0.515 and r = 0.696, respectively), whichwas opposite to that observed for CVP or LVEDAI. Areas underROC curves for FTc [0.944 (SD 0.058)] and PPV [0.909 (0.069)]were significantly greater than those for CVP [0.540 (0.133),P < 0.001] and LVEDAI [0.495 (0.133), P < 0.001]. Theoptimal threshold value given by ROC analysis was 357 ms forFTc. Conclusions: In this study, FTc predicted fluid responsiveness. However,FTc should be used in conjunction with other clinical information.     

动脉置管处改良采血法检测血气分析与APTT的可行性研究

目的探讨从肝素维持的动脉置管处采集血标本的方法,避免浪费血液。方法对30例带有动脉测压置管患儿,用常规法(弃含有肝素的血液3mL)和改良法(不弃血)分别先后从动脉置管处采血。结果两组血气分析,生化指标即钾(K+)、钠(Na+)、红细胞压积(Hct)、活化部分凝血活酶时间(APTT)比较,差异无统计学意义(均P>0.05)。结论从以肝素维持的动脉置管中采血,不弃血采血法可以替代常规采血法,检测血气分析、生化指标可行。     

Validation of a point‐of‐care prothrombin time test after cardiopulmonary bypass in cardiac surgery

Point‐of‐care coagulation monitoring can be used for the guidance of haemostasis management. However, the influence of time on point‐of‐care prothrombin time testing following protamine administration after cardiopulmonary bypass has not been investigated. Bland–Altman and error grid analysis were used to analyse the level of agreement between prothrombin time measurements from point‐of‐care and laboratory tests before cardiopulmonary bypass, and then 3 min, 6 min and 10 min after protamine administration. Prothrombin times were expressed as International Normalised Ratios. While the point‐of‐care and laboratory prothrombin time measurements showed a high level of agreement before bypass, this agreement deteriorated following protamine administration to a mean (SD) bias of ?0.22 (0.13) [limits of agreement 0.48–0.04]. Error grid analysis revealed that 35 (70%) of the paired values showed a clinically relevant discrepancy in international normalised ratio. At 3 min, 6 min and 10 min after cardiopulmonary bypass there is a clinical unacceptable discrepancy between the point‐of‐care and laboratory measurement of prothrombin time.     

It is the goal of this section to publish material that provides information regarding specific issues, aspects of artificial organ application, approach, philospphy, suggestions, and/or thoughts for the future. New Bedside Test for Monitoring Anticoagulation During Hemodialysis

Heparin therapy in patients can be monitored bedside during dialysis treatment by activated partial thromboplastin time (APTT) measurements using portable coagulation monitors. We verified the efficacy of the CoaguChek Plus System (Boehringer Mannheim, GmbH, Mannheim, Germany) for this purpose. The first series of results was obtained using CoaguChek Plus APTT controls (Level 1 and Level 2) on 3 instruments. The coefficients of variation (CVs) were found to be in the range of 3.6 to 5.0% based on results per instrument (n = 20) and per control level (n = 60). The second series of results was obtained using whole blood drawn from the arterial lines of patients during dialysis treatment. Three determinations out of 1 ml of fresh whole blood gave an overall mean CV of 4.9% from the 123 samples tested. Samples were taken before the onset of heparin treatment, 2 h after treatment was started, and at the end of treatment. The CoaguChek Plus APTT measurements were compared to measurements made using laboratory routine method STA APTT (Boehringer Mannheim GmbH) with results from 104 whole blood samples. Regression analysis according to Passing and Bablok showed good correlation (r = 0.885) and good agreement ( y = 0.997 x − 6.6) between both methods. Ease of use, excellent performance, reliability, and rapid availability of results within 3 min make the CoaguChek Plus APTT measurements suitable for monitoring patients during dialysis.     

The detection of changes in heparin activity in the rabbit: a comparison of anti-xa activity,thrombelastography, activated partial thromboplastin time,and activated coagulation time

Thrombelastography (TEG) has been used to detect both exogenous and endogenous circulating heparin activity in clinical and laboratory settings. Thus, in this study I sought to compare the sensitivity of TEG, activated partial thromboplastin time (aPTT), and activated coagulation time (ACT) values with changes in anti-Xa activity after small-dose heparin administration in rabbits. Conscious rabbits (n = 11) had blood obtained from ear arteries for hematological analyses after the administration of 0, 10, 20, and 30 U/kg of IV heparin. Anti-Xa activities after the administration of 0, 10, 20, and 30 U/kg of heparin were, respectively, 38 +/- 9 mU/mL, 74 +/- 15 mU/mL, 105 +/- 14 mU/mL, and 134 +/- 17 mU/mL; all values were significantly different from each other. TEG variables (R and alpha) significantly (P < 0.05) changed between 0, 10, and 20 U/kg heparin doses, but a difference between 20 and 30 U/kg could not be discerned secondary to loss of a detectable clot. The aPTT was significantly (P < 0.05) different between 0, 20, and 30 U/kg doses. ACT values were significantly different between the 0 U/kg heparin dose and all other doses; however, there were no significant differences between the 10, 20, and 30 U/kg heparin doses. Changes in anti-Xa activity were significantly linearly related to R (r = 0.81, P < 0.0001), alpha (r = -0.85, P < 0.0001), aPTT (r = 0.74, P < 0.0001), and ACT (r = 0.41, P = 0.005). In this model of small-dose heparin administration, TEG variables were more sensitive to changes in heparin activity than aPTT and ACT. IMPLICATIONS: Changes in thrombelastography (TEG) variables more sensitively reflect changes in circulating heparin activity than activated partial thromboplastin time (aPTT) and activated coagulation time (ACT) after small-dose heparin administration in rabbits. Thus, TEG may be more helpful than aPTT and ACT in the detection of heparin in both laboratory and clinical settings wherein heparin may play a role in coagulopathy.     

Intraoperative gastric tonometric examinations in children and infants with a new probe, combined with measurement of the endtidal PCO2

Background: Important progress relating to the early prediction of postoperative complications was recently achieved through the combined use of endtidal PCO₂ (P_ETCO₂) and gastric tonometry. The aim of this article was to present results obtained with a new tonometric instrument, proving its feasibility and extending its use to the control of anesthetized infants and children. Methods: The new tonometric probe, which is balloon free, consists basically of silicone rubber tubing. The room air initially inside the tubes of the probe equilibrates with the PCO₂ of the body cavity throughout its full length. The PCO₂ content of the gastric cavity (P_gCO₂) and simultaneously P_ETCO₂ were measured with a microcapnograph. A total of 108 measurements were performed intraoperatively on 25 infants and young children operated on at the Surgical Unit of the Department of Pediatrics. The patients were divided into elective surgery cases <2 years of age, group I; elective surgery cases >2 years of age, group II; and acute surgery cases, independently of age, group III. To examine the degree of agreement between the measurements, Pearson’s correlation coefficients were determined and Bland–Altman analysis was performed. A mixed model repeated measurements anova was used to compare the differences between the groups. Results: P_ETCO₂ and P_gCO₂ for groups I and II were nearly identical, and statistically not significantly different (mean difference 0.10 mmHg and 0.85 mmHg, P = 0.96 and 0.45, respectively), whereas the corresponding data for group III differed significantly from those for groups I and II (P = 0.03 and 0.001, respectively). On Bland–Altman analysis, the bias value for groups proved to be statistically significantly different (P = 0.001). Conclusions: The tested new probe worked very well in small children. The clinical implications of the large gaps found between P_ETCO₂ and P_gCO₂ values in acutely ill children and children undergoing elective operations must be investigated further.     

Cardiac output measurement in children: comparison of Aesculon cardiac output monitor and thermodilution

Background: We compared cardiac output (CO) measurements by the non-invasiveelectrical velocimetry (Aesculon^®) monitor with the pulmonaryartery catheter (PAC) thermodilution method in children. Methods: CO values using the Aesculon^® monitor and PAC thermodilutionwere simultaneously recorded during cardiac catheterizationin children. Measurements were performed under general anaesthesia.To compare, three consecutive measurements for each patientwithin 3 min were obtained. The means of the three values werecompared using simple regression and Bland–Altman analysis.Data were presented as mean (SD). A mean percentage of <30%was defined to indicate clinical useful reliability of the Aesculon^®monitor. Results: A total of 50 patients with a median (range) age of 7.5 (0.5–16.5)yr were enrolled in the study. Mean CO values were 3.7 (1.5)litre min^–1 (PAC thermodilution) and 3.1 (1.7) litre min^–1(Aesculon^® monitor). Analysis for CO measurement showeda good correlation between the two methods (r=0.894; P<0.0001).The bias between the two methods was 0.66 litre min^–1with a precision of 1.49 litre min^–1. The mean percentageerror for CO measurements was 48.9% for the Aesculon^® monitorwhen compared with PAC thermodilution. Conclusions: Electrical velocimetry using the Aesculon^® monitor did notprovide reliable CO values when compared with PAC thermodilution.Whether the Aesculon^® monitor can be used as a CO trendmonitor has to be assessed by further investigations in patientswith changing haemodynamics.     

Predictors of warm ischemia time and perioperative complications in a multicenter, international series of robot-assisted partial nephrectomy

Background

Warm ischemia time (WIT) and complication rates are two important parameters for evaluating the perioperative results of robot-assisted partial nephrectomy (RAPN). Few data are available about the clinical predictors of WIT and overall complications.

Objective

To identify clinical predictors of WIT and perioperative complications.

Design, setting, and participants

This is a retrospective study including 347 patients who underwent RAPN for suspicious renal cell carcinoma (RCC) at four referral centers from September 2008 to September 2010.

Intervention

All patients underwent RAPN using the da Vinci S Surgical System with hilar clamping.

Measurements

WIT >20 min and overall complication rates were the main outcomes. Postoperative complications were classified according to the Clavien/Dindo system. Moreover, the following perioperative variables were considered: clinical tumor size, anatomical tumor characteristics according to Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) classification score, surgeon experience, console time, blood loss, and upper collecting system (UCS) repair.

Results and limitations

WIT >20 min was reported in 125 (36%) cases. Intraoperative and postoperative complications were observed in 10 (2.9%) and 41 (11.8%) cases, respectively. Surgeon experience (odds ratio [OR]: 6.381; 95% confidence interval [CI], 3.687-11.042; p < 0.001), clinical tumor size (OR: 1.022; 95% CI, 1.002-1.044; p = 0.03), the other anatomic characteristics determined by the PADUA classification score (OR: 1.294; 95% CI, 1.080-1.549; p = 0.005), and the UCS repair (OR: 2.987; 95% CI, 1.728-5.165; p < 0.001) turned out to be independent predictors of WIT >20 min. Similarly, surgeon experience (OR: 3.937; 95% CI, 2.011-7.705; p < 0.001), clinical tumor size (OR: 1.033; 95% CI, 1.009-1.058; p = 0.007), and the other anatomical characteristics determined by the PADUA classification score (OR: 1.427; 95% CI, 1.149-1.773; p < 0.001) turned out to be independent predictors of overall complication rates. The retrospective design is the main limitation of this multicenter, international study. Therefore, some patient characteristics and comorbidities were not recorded.

Conclusions

Anatomic tumor characteristics as determined by the PADUA classification score were independent predictors of WIT and overall complications, once adjusted for the effects of surgeon experience and clinical tumor size.     

Prospective study of robotic partial nephrectomy for renal cancer in Japan: Comparison with a historical control undergoing laparoscopic partial nephrectomy

Objectives

To evaluate the outcomes of robotic partial nephrectomy compared with those of laparoscopic partial nephrectomy for T1 renal tumors in Japanese centers.

Methods

Patients with a T1 renal tumor who underwent robotic partial nephrectomy were eligible for inclusion in the present study. The primary end‐point consisted of three components: a negative surgical margin, no conversion to open or laparoscopic surgery and a warm ischemia time ≤25 min. We compared data from these patients with the data from a retrospective study of laparoscopic partial nephrectomy carried out in Japan.

Results

A total of 108 patients were registered in the present study; 105 underwent robotic partial nephrectomy. The proportion of patients who met the primary end‐point was 91.3% (95% confidence interval 84.1–95.9%), which was significantly higher than 23.3% in the historical data. Major complications were seen in 19 patients (18.1%). The mean change in the estimated glomerular filtration rate in the operated kidney, 180 days postoperatively, was ?10.8 mL/min/1.73 m² (95% confidence interval ?12.3–9.4%).

Conclusions

Robotic partial nephrectomy for patients with a T1 renal tumor is a safe, feasible and more effective operative method compared with laparoscopic partial nephrectomy. It can be anticipated that robotic partial nephrectomy will become more widely used in Japan in the future.

     

Detection of awareness in surgical patients with EEG-based indices--bispectral index and patient state index

Background. Patient state index (PSI) and bispectral index (BIS)are values derived from the EEG, which can measure the hypnoticcomponent of anaesthesia. We measured the ability of PSI andBIS to distinguish consciousness from unconsciousness duringinduction and emergence from anaesthesia and a period of awarenessin surgical patients. Methods. Forty unpremedicated patients were randomized to receive:(1) sevoflurane/remifentanil (     

Isolation and partial characterization of crystal matrix protein as a potent inhibitor of calcium oxalate crystal aggregation: evidence of activation peptide of human prothrombin

In order to clarify the characteristics of crystal matrix protein (CMP), which exhibits a remarkable affinity for calcium oxalate crystals and may be important in stone pathogenesis, we have isolated CMP from macromolecular matrix substances of newly-formed calcium oxalate crystals. Purification of CMP consisted of calcium oxalate crystal formation, dissolution of crystals, electrodialysis, anion exchange chromatography and high-performance liquid chromatography. CMP showed the protein band of 31 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence of CMP was identical to that of human prothrombin. Both anti-CMP polyclonal antibody and antihuman prothrombin antibody cross-reacted well with human prothrombin and CMP in Western blotting. Its amino acid composition and its molecular weight of 31 kDa strongly suggest that CMP is the activation peptide of human prothrombin.