Evaluation of a new method and instrument for detection platelet aggregation function and its clinical application / 中国实验血液学杂志

This study was purpose to evaluate a new method and instrument for detecting platelet aggregation function, establish the reference intervals for PL-11 platelet analyzer, and evaluate its clinical application. The evaluation was based on the guidelines of Clinical and Laboratory Standards Institute (CLSI or NCCLS) and Clinical Laboratory Improvement Amendment 88. Intravenous blood samples anticoagulated with sodium citrate were detected by PL-11 platelet analyzer. The reference intervals were defined after statistic analysis. The clinical diagnostic significance of the PL-11 platelet analyzer was evaluated by testing the change rate of platelet maximum aggregation rate (MAR) of acute cerebral infarction (ACI) patients in the department of Neurology who took clopidogrel 7 d before and after. The result showed that all the parameters meet the standard of CLIA'88. The platelet MAR of 247 healthy volunteers which was induced by PLR-06, PLR-07, PLR-09 and PLR-10, was detected by the PL-11 platelet analyzer, respectively. The MAR is 58.8 ± 10.1 (%), 61.2 ± 11.8 (%), 51 ± 10.2 (%), 53.1 ± 9.2 (%), respectively. The MAR of ACI patients is significantly lower than that after taking clopidogrel. It is concluded that the PL-11 platelet analyzer is an ideal platelet function detector for early warning and diagnosis of thromboembolic disease, which is worthy to be extended and applied.

Evaluation of cardioprotective effect of ischemic preconditioning on ischemic myocardium using 99Tcm-Syt I-C2A in the myocardial ischemia-reperfusion rat model / 中华核医学杂志

Objective Precondition is an approach to myocardial protection during ischemia-reper-fusion by inhibiting myocardial cell apoptosis.The purpose of this study was to evaluate the cardioprotective effect using 99Tcm-syuaptotagmin I (Syt I)-C2A to detect myocardial cell apoptosis in the myocardial is-chemia-repedusion rat model.Methods (1) The C2A domain of Syt I was labeled with 99Tcm using 2-iminothiophene hydrochloride (IT) method.Radiochemical purity was determined with thin layer chroma-tography.The binding activity of radiolabeled protein was assessed using eamptothecin-treated Jurket cells.(2) One group of 6 rats was prepared for myocardial ischemia-reperfusion model(A group),and another group of 6 rats was prepared for myocardial ischemia precondition model(B group).99Tcm-Syt I-C2A was injected via the tail vein at a dosage of about 7.4 MBq.At 1h after injection,the rat was sacrificed,and the heart was removed to rinse with saline and dye with triphenyl tetrazolium eoride (TTC).According to the resdt of myocardial dye,theischemic myoeardium was separated from the viable myocardium and weight was measured,and then its radioactivity was determined by gamma counting.The difference of radioactive uptake in the ischemic myocardium between these two group models was compared using percentage activity of injection dose per gram of tissue(%ID/g)±standard deviation(x±s).SPSS 12.0 was used for data analy-sis,and t-test was used to compare data.Results (1) The radiochemical purity of 99Tcm-Syt I-C2A was (98.90±0.43)%,and the radioactivity in the camptothecin-treated group was (10.99±0.55) folds higher than that of non-treated viable control group.(2)In the ischemia-reperfusion model,the radioactive uptake of 99Tcm-Syt,I-C2A was(2.41±0.32)%ID/g in the ischemic myocardium,and(0.16±O.02)%ID/g in the nomud myocardiunm.However,in the myocardial ischemia precondition model,(0.46±0.05)%ID/g in the isehemic myocardium was measured,and(0.20±0.05)%ID/g in the normal myocardium.Uptake of 99Tcm-Syt I-C2A in ischemic myocrdium showed statistically significant difference (t=8.52,P<O.01) between these two groups of models.Conclusion 99Tcm-C2A-glutathione S-transferase (GST) may be used to quantita-tively detect cardioprotective effect of ischemic precondition,which could inhibit myocardium apoptosis on ischemic myocardium in the ischemia-reperfusion rat model.

Determination of ADAMTS13 antigen and activity levels in patients with acute myocardial infarction and acute ischemic stroke / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the ADAMTS13 antigen levels and activity in patients with acute myocardial infarction (AMI) and acute ischemic stroke (AIS), and explore its significance in these diseases.</p><p><b>METHODS</b>ADAMTS13 activity levels were detected by a new developed Frests-vWF73 kit, ADAMTS13 antigen levels by ELISA kit, and vWF multimers by electrophoresis.</p><p><b>RESULTS</b>ADAMTS13 antigen in normal control, AMI and AIS was (878 +/- 198), (618 +/- 188) and (702 +/- 155) U/L, and ADAMTS13 activity was (81.7 +/- 13.9)%, (59.2 +/- 22.1 )% and (65.4 +/- 15.8)%, respectively, being significantly decreased in AMI and AIS patients.</p><p><b>CONCLUSION</b>ADMATS13 might involve in arterial infarction diseases.</p>

Noninvasive detection of experimental vulnerable atherosclerotic plaques with 99Tc m labeled C2A domain of synaptotagmin I / 中华心血管病杂志

<p><b>OBJECTIVE</b>(99)Tc(m) labeled C2A domain of synaptotagmin I ((99)Tc(m)-Syt I-C2A) is used for noninvasive detection of vulnerable atherosclerotic plaque.</p><p><b>METHODS</b>Recombinant C2A domain of synaptotagmin I, overexpressed in E. Coli, was thiolated with 2-iminothiolane (2-IT) and labeled with (99)Tc(m). Atherosclerotic plaques were produced in 5 rabbits by deendothelialization of the abdominal aorta and the rabbits were fed with cholesterol diet for 3 months. Three rabbits not manipulated served as normal controls. All animals were injected with (99)Tc(m)-Syt I-C2A and underwent in vivo imaging thereafter. Aortas were then explanted for ex vivo imaging and histological characterization.</p><p><b>RESULTS</b>In deendothelialized animals, intense radio-uptake in abdominal aorta, showed by gamma camera at 2 h after injection, was visualized and T/B was 3.25 +/- 0.51 by ROI measurement, quantitative uptake ratio of abdominal aortas with atherosclerotic lesions to thoracic aortas was 8.39 +/- 1.74 in ex vivo imaging. The mean uptake in specimens of abdominal aortas with lesions was 12.6-fold higher than in control abdominal aortas, and 10.2-fold higher than in thoracic aortas of deendothelialized animals by gamma-counter.</p><p><b>CONCLUSION</b>(99)Tc(m)-Syt I-C2A has a high affinity for vulnerable atherosclerotic plaque and is a suitable a gent for the noninvasive detection of vulnerable atherosclerotic plaque.</p>

Technetium-99m labeled synaptotagmin I C2A detection of paclitaxel-induced apoptosis in non-small cell lung cancer / 中华肿瘤杂志

<p><b>UNLABELLED</b>Objective To evaluate the efficacy of 99mTc-labeled C2A probe in detection of apoptosis of non-small cell lung cancer (NSCLC) cells after chemotherapy.</p><p><b>METHODS</b>Imaging studies were performed in NSCLC H460-bearing mice. The mice were divided into 2 groups: the paclitaxel-treated group and control group. 99mTc-C2A was injected intravenously at 12, 24, 48 and 72 h after chemotherapy. Images were acquired at 3 h and 6 h after injection using a pinhole collimator. The regions of interest (ROI) were drawn in tumor area and contralateral nomal tissue, and the ratio of T/NT were caculated. The tumor sections were stained by HE and TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-nick-end labeling) staining to confirm the presence of apoptosis. Activated caspase-3 was also analyzed with flow cytometry.</p><p><b>RESULTS</b>Little uptake of 99mTc-C2A was found in baseline images, but tumor uptake increased very much after chemotherapy, the T/NT ratio was 1.79 +/- 0.34, 2.23 +/- 0.33 and 2.78 +/- 0.34, respectively. The T/NT ratio of control was 1.48 +/- 0.23. Tumor uptake (% ID/g) of 99mTc-C2A in chemotherapy groups were 2.82 +/- 0.90, 3.13 +/- 0.48 and 3.52 +/- 1.18, respectively. Tumor uptake (% ID/g) in the control group was 1.21 +/- 0.51. It in paclitaxel-treatment groups were 2.82 +/- 0.90, 3.13 +/- 0.48 and 3.51 +/- 1.18, respectively, significantly higher than that in untreated mice. Furthermore, the uptake of 99mTc-C2A correlated well with apoptotic index (r = 0.56, P < 0.01), and activated caspase-3 (r = 0.59, P < 0.01).</p><p><b>CONCLUSION</b>Our preliminary results demonstrated that 99mTc-C2A imaging in vivo for detection of cell death in solid tumors is feasible and well correlated with TUNEL staining and activated caspase-3. The C2A holds promise and warrants further development as a molecular probe to early predict cancer treatment efficacy.</p>

Expression of platelet collagen receptor-glycoprotein VI fragment in E. coli and its biological activities / 中国实验血液学杂志

This study was aimed to further investigate the function of platelet collagen receptor-glycoprotein VI and to screen its specific inhibitor. The extracellular domain of platelet glycoprotein VI (GPVI) in E. coli was expressed by recombinant technology, the extracellular domain cDNA of GPVI was amplified from pBluescript KS(-)-GPVI plasmid by PCR. Proved by sequencing, the expression vector pET-20b(+)-GPVI was constructed, which was then transformed into E. coli (BL21(DE3)pLysS) and induced by IPTG. The recombinant GPVI was purified on Ni-NTA resin column and renatured in PBS containing GSH and GSSG. The anti-penta His McAb and anti-GPVI polyclonal antibody were used to identify the recombinant GPVI in Western blotting. Collagen binding test was conducted to investigate the biological activity of recombinant GPVI. The results showed that the recombinant GPVI was expressed in E. coli and successfully purified, which was confirmed to be similar to the native GPVI in Western blotting. The recombinant GPVI can bind the type I collagen in dose-dependent manner. In conclusion, the recombinant GPVI can be achieved in E. coli and restore its native characteristics after renaturation.

Expression of von willebrand factor-A3 domain in E coli and its biological function / 中国实验血液学杂志

The interaction among collagen, von Willebrand factor (vWF) and glycoprotein Ib axis is the first step in hemostasis and thrombosis, especially under high shear condition. To develop a new remedy of anti-thrombosis, mRNA from endothelial cells was extracted, and reverse transcription PCR was adopted to amplify DNA of interest. After sequencing, recombinant expression vector was constructed. The amplified DNA fragment of vWF domain A3 was inserted into expression vector with 6 x his taq, pET20b(+), the recombinant was transformed into E coli (strain DE3) and induced by IPTG. Recombinant vWF-A3 was designated as a recombinant fragment comprising residues 918 - 1114 of mature vWF subunit. It was purified through Ni-NTA resin column and refolded in Tris buffer containing GSH and GSSG. The results showed that rvWF-A3 was expressed successfully in E coli (strain DE3), accounting for 46% of total bacterial protein with its purity of over 95%. It was identified that rvWF-A3 is capable to bind collagen and inhibit the wild vWF binding to collagen by competition. It is concluded that rvWF-A3 fragment might be an effective antithrombotic agent for preventing arterial thrombosis.

Molecular cloning of human vWF/A1 gene and its expression / 中国实验血液学杂志

To study the mechanism of thrombogenesis and search new anti-thrombotic agent, the cDNA for human vWF A1 domain was high-level expressed in E. coli and recombinant protein of vWF A1 with biologic activity was obtained. The gene encoding A1 domain was amplified by PCR from plasmid containing full length cDNA of human vWF. After confirming by DNA sequencing analysis, the recombinant expression plasmid pQE31-vWF/A1 was constructed and introduced into E. coli M15 strain, then induced by IPTG; the expressed protein was purified with Ni-NTA agarose, identified by Western blotting. The results showed that the 854 bp DNA fragment was obtained by PCR from the plasmid containing full length cDNA for human vWF and its sequence was identical to the published sequence. High level expression of A1 protein was yielded after 5 hour-induction, which amounted to 30% of total bacteria protein in inclusion body. Western blot demonstrated it possessed good antigenicity and high specificity. It is concluded that cDNA for vWF/A1 had been cloned successfully, high level expression of A1 protein was achieved in E. oli. This study will provide a basis for the further clinical and basic research on the role of vWF in thrombosis and hemostasis.