Effect of aspirin on function of human umbilical cord blood-derived late endothelial progenitor cells / 中国实验血液学杂志

This study was aimed to investigate whether aspirin has effect on function of late endothelial progenitor cells (EPC). Cord blood CD34(+) cells were purified using the ficoll density gradient centrifugation and human CD34 positive selection kit, then the cells were inoculated on fibronectin-coated culture plate. After culture for 2 weeks, adherent cells were identified as EPC by flow cytometry, immunofluorescence, RT-PCR, uptake of Dil-Ac-LDL and matrigel tube formation assay. EPC were treated with different concentrations of aspirin (0.1, 1, 10, 100, 1 000, 10 000 µmol/L) for 24 h, then the proliferation, adhesion and migration ability of these cells were analyzed by CCK-8 assay and transwell methods. The results indicated that the low concentrations of aspirin (0.1 and 1 000 µmol/L) promoted late EPC adhesive and migratory capacity, but no obvious effect on proliferation of late EPC were observed. On the other hand, the high concentrations of aspirin (10 000 µmol/L) inhibited proliferation and migratory capacity of EPC, but had no obvious effect on adhesive ability of EPC. It is concluded that low concentration of aspirin promotes migration and adhesion of late EPC, while the high concentration of aspirin decreases EPC proliferation and migratory capacity of EPC.

Increased susceptibility of recombinant type 2A von Willebrand factor mutant A1500E to proteolysis by ADAMTS13 / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the susceptibility of von Willebrand factor (VWF) type 2A mutant A1500E to proteolysis by metalloprotease ADAMTS13 and to provide the direct supports for the pathogenesis of VWF mutation A1500E responsible for von Willebrand disease (VWD) type 2A.</p><p><b>METHODS</b>Recombinant wild-type VWF (WT-VWF) and A1500E mutant VWF transiently expressed on transfected HeLa cell lines. Expression media were collected and concentrated, then cleaved directly by recombinant ADAMTS13 (rADAMTS13). Compared with WT-VWF, the susceptibility of A1500E mutant VWF to proteolysis by ADAMTS13 was analyzed using SDS-agarose gel VWF multimers analysis.</p><p><b>RESULTS</b>In vitro the expression of VWF:Ag in the supernatants of WT-VWF and A1500E mutant VWF were 1.10 U/ml and 0.78 U/ml, respectively, while VWF:Ag in cells lysates of A1500E mutant VWF was 90.6% of that of WT-VWF. The SDS-agarose gel VWF multimers analysis showed that there were no differences between WT-VWF and A1500E mutant VWF. The A1500E mutant VWF could be efficiently cleaved by ADAMTS13 under static condition without denaturants such as urea and guanidine HCl. VWF multimeric analysis showed that high and intermediate molecular weight multimers dramatically decreased while low molecular weight multimers obviously increased. Conversely, WT-VWF could not be cleaved by ADAMTS13 under the same condition.</p><p><b>CONCLUSION</b>The A1500E mutation resulted in VWF more susceptible to ADAMTS13-dependent proteolysis, which belonged to VWD type 2A group 2 mutation.</p>

Effect of vascular endothelial growth factor-C on the cell growth and angiogenesis in NB4 cell xenograft tumor / 中华血液学杂志

<p><b>OBJECTIVE</b>To establish NB4/VEGF-C cells xenograft in nude mice model, and explore the effect of VEGF-C on hematological malignancies</p><p><b>METHODS</b>NB4/VEGF-C or NB4/pcDNA3.1 cell lines were established by transfecting the recombinant pcDNA3.1-VEGF-C plasmid and the vacant pcDNA3.1 vector into NB4 cells. The recombinant VEGF-C was identified by RT-PCR and Western blotting. Eighteen male BALB/c nude mice aged 4 - 5 weeks were equally divided into two groups. Mice irradiated by 4 Gy ⁶⁰Co were subcutaneously injected with 1 × 10⁷NB4/VEGF-C or NB4/pcDNA3.1 cells into one side of axilla. The volumes of xenograft tumor was evaluated according to L × t² × 0.52. Microvessel density (MVD) on the xenograft tumor section was detected by IHC with VWF antibody.</p><p><b>RESULTS</b>NB4 cell xenograft tumors were developed in all mice of both the two groups. The growth of NB4/VEGF-C cells in nude mice was faster than in controls. There were statistically significant differences in the volume and weight of xenograft tumor between NB4/VEGF-C and NB4/pcDNA3.1 cell groups \[(631.44 ± 114.42) mm³ vs (491.22 ± 70.05) mm³\] (P = 0.006) and \[(321.78 ± 27.84) mg vs (288.57 ± 40.12) mg\] (P = 0.031), respectively. MVD in xenograft tumor of NB4/VEGF-C cells \[(50.8 ± 11.7)/mm²\] was higher than that in controls \[(18.9 ± 7.0)/mm²\] (P = 0.021). The Bcl-2 protein level in NB4/VEGF-C cells xenografts was higher than that in controls.</p><p><b>CONCLUSION</b>VEGF-C could promote proliferation of NB4 cells by inducing angiogenesis and inhibit cells apoptosis by upregulating antiapoptotic Bcl-2 protein expression in NB4 cells xenograft tumor.</p>

Expression of vWF73 and VWF114 fragments of von Willebrand factor A2 domain and their utilization in detecting ADAMTS13 activity / 中华血液学杂志

<p><b>OBJECTIVE</b>To construct the expression vectors of vWF73 and vWF114 fragments of von Willebrand factor (vWF) A2 domain, and to express glutathione S-transferase (GST) fusion proteins in E. coli, and to explore their values in measuring ADAMTS13 activity as substrates.</p><p><b>METHODS</b>The DNA fragments encoding vWF73 and vWF114 were generated using PCR and separately cloned into pGEX-6P-1, a Schistosoma japonicum GST fusion expression vector. The expression of GST-vWF73-H and GST-vWF114-H was induced in liquid culture, followed by purification with Ni-NTA agarose column. The cleavage of two GST fusion proteins by recombinant ADAMTS13 (rADAMTS13) or plasma from normal individuals and thrombotic thrombocytopenic purpura (TTP) patients were identified by Western blot. Based on an enzyme-linked immunosorbent assay (ELISA) with anti-GST and anti-His monoclonal antibodies, GST-vWF73-H and GST-vWF114-H were used to measure plasma ADAMTS13 activity as substrates.</p><p><b>RESULTS</b>Two small molecular substrates of ADAMTS13, GST-vWF73-H and GST-vWF114-H, are expressed and purified, which could be specifically cleaved by rADAMTS13 or plasma from healthy individuals, but not by plasma from congenital or idiopathic TTP patients. An ELISA assay was established to detect plasma ADAMTS13 activity using GST-vWF73-H and GST-vWF114-H as substrates.</p><p><b>CONCLUSIONS</b>Two GST fusion proteins in vWF A2 domain, vWF73 and vWF114, were expressed effectively using a prokaryotic expression system and could be used to detect ADAMTS13 activity as substrates.</p>

Research on the C-terminal domain of ADAMTS13 regulates its cleaving activity / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the influence of C-terminal domain of ADAMTS13 on its cleaving activity.</p><p><b>METHODS</b>The full-length wild-type (WT) and C-terminal domain truncated type (TT, TSP8 + CUB domains were deleted) of human ADAMTS13 recombinant protein were transfected into and permanent expressed on Hela cells. Western blot and R-CBA were used to directly detect the activities of the two recombinant proteins under the static and stressed condition respectively. ELISA was used to compare the binding abilities of the two proteins by coating with vWF.</p><p><b>RESULTS</b>The recombinant proteins were identified by Western blot with anti-his-tag or anti-ADAMTS13 antibodies. With pretreatment of 1.5 M urea, the enzyme activity of TT was significantly higher than that of WT, and so did in binding ability with vWF While, only WT could cleave vWF under high stress.</p><p><b>CONCLUSION</b>The distal carboxyl-terminal TSP8 together with CUB domains of ADAMTS13 may affect the enzyme activity by regulating the binding of ADAMTS13 to vWF in different conditions, and they are very important for the enzyme activity under high stress force condition.</p>

Inherited dysfibrinogenemia caused by Arg16His mutation in alpha chain of fibrinogen / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the phenotype and genotype of a family with inherited dysfibrinogenemia.</p><p><b>METHODS</b>Assays of coagulation, including activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT), were carried out with Stago Compact in the proband and his family members. The activity and antigen of fibrinogen in plasma were determined by Clauss and immunoturbidimetry, respectively. Fibrinogen and its constituent were analyzed by Western blot with nonreducing 4%-20% SDS-polyacrylamide gel electrophoresis (PAGE). All exons and exon-intron boundaries of fibringen genes FGA, FGB and FGG were analyzed by PCR and then direct sequencing.</p><p><b>RESULTS</b>The proband had normal APTT and PT, but prolonged TT. The activity of fibrinogen in plasma was decreased while its antigen level was normal. These abnormalities were also found in his mother and a sister. Genetic analysis revealed heterozygous G1233A in the exon 2 of FGA originating from his mother, which resulted in Arg16His missense mutation.</p><p><b>CONCLUSION</b>Inherited dysfibrinogenemia was caused by Arg16His mutation in exon 2 of FGA, and this is the first case reported in a Chinese family.</p>

Evaluation and clinical application of a new method for detecting ADAMTS13 activity / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>A severe deficiency of ADAMTS13 activity contributes to the pathogenesis of thrombotic thrombocytopenic purpura (TTP). Measuring the activity of ADAMTS13 is helpful for the diagnosis of TTP and the prognostic monitor in TTP patients. Most available assays are cumbersome and costly, so not easily adapted to routine laboratories. ADAMTS13 cleaves von Willebrand factor (VWF) within the domain A2, located between domains A1 and A3. Therefore, specific assays for ADAMTS13 activity could be based on the different structures of VWF before and after the cleavage. Using this hypothesis we try to establish a new and simple method to determine ADAMTS13 activity.</p><p><b>METHODS</b>First, plasma samples were exposed in denaturing condition to allow cleavage of VWF by ADAMTS13. Then, the ADAMTS13 activity was measured with two novel monoclonal antibodies, SZ-129 and SZ-125, which specifically recognize the VWF A1 and A3 domains by using a two-site sandwich ELISA. Compared with a residual-collagen binding assay (R-CBA), plasma ADAMTS13 activities in 161 samples were assessed, and the inhibitory activities of ADAMTS13 autoantibody in 24 TTP patients were determined. The relationship of these two assays was analyzed by linear correlation, and the sensitivity and specificity of the new assay was also evaluated.</p><p><b>RESULTS</b>Plasma ADAMTS13 activities in normal people and TTP, acute myocardial infarction (AMI), and idiopathic thrombocytopenic purpura (ITP) patients determined by the new assay were (89.75 +/- 7.93)%, (17.63 +/- 18.71)%, (68.55 +/- 18.08)%, (85.83 +/- 9.84)%, respectively. Results were consistent with those of R-CBA, the squared correlation factor was 0.9183 of the two assays. The new assay can easily discriminate a TTP plasma sample from a non-TTP plasma sample (P < 0.01), and the coefficient of variation for the new assay was 6.17%. In 23 idiopathic TTP patients, the inhibitor activity of ADAMTS13 autoantibody ranged from 12% to 100%, while no inhibitory activity was detected in one hereditary TTP patient.</p><p><b>CONCLUSION</b>This new and simple assay for ADAMTS13 activity could be used routinely in the clinic to determine the activity of ADAMTS13.</p>

Development of a monoclonal antibody to factor VIII C2 domain and its functional study / 中华血液学杂志

<p><b>OBJECTIVE</b>To develop a monoclonal antibody (mAb) directed to FVIII C2 domain and investigate its effect on FVIII activity.</p><p><b>METHODS</b>FVIII C2 protein was expressed in E. coli and purified. A murine antihuman FVIII C2 domain mAb SZ-132 was developed by standard hybridoma technology and characterized. In coagulation assays, different concentrations of SZ-132 were incubated with freshly collected pooled human plasma and the residual activity of FVIII and activated partial thromboplastin time (APTT) were determined. The effects of SZ-132 on rhFVIII binding to purified human vWF, phosphatidylserine (PS) and platelets were assessed by enzyme linked immunosorbent assays (ELISA).</p><p><b>RESULTS</b>SZ-132 could inhibit FVIII procoagulant activity in a dose-dependent manner within the concentrations of 0-25 microg/ml and the FVIII activity was completely inhibited on above 25 microg/ml. It could also prevent rhFVIII from binding to vWF, PS and platelets.</p><p><b>CONCLUSIONS</b>SZ-132 is a neutralizing mAb against FVIII C2 domain and can inhibit FVIII procoagulant activity by preventing FVIII from binding to vWF and PS.</p>

Effects of Annexin II gene silencing by siRNA on proliferation and invasive potential of Jurkat lymphoma cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of Annexin II (AnxA2) gene silencing by siRNA on proliferation and invasive potential of lymphoma cell line Jurkat cells.</p><p><b>METHODS</b>A synthesized siRNA duplex targeting to AnxA2 was transfected into Jurkat cells. Transfection efficiency was analyzed by real-time PCR and flow cytometry. MTT assay for cell proliferation and transwell plates for invasive potential were performed.</p><p><b>RESULTS</b>Compared with the negative controls, the cell proliferation inhibitory rate of the AnxA2 siRNA transfected Jurkat cells was significantly increased at 24 h, 48 h and 72 h [(17.4 +/- 2.3)%, (22.4 +/- 3.8)%, (37.6 +/- 1.5)% vs (-1.3 +/- 5.1)%, (-5.5 +/- 4.4)%, (-10.8 +/- 5.5)%, respectively, P<0.05]. The cell invasive potential of the transfected Jurkat cells was inhibited remarkably at 48 h (11.3 +/- 4.2 vs 54.3 +/- 8.7, P<0.01).</p><p><b>CONCLUSION</b>AnxA2 gene silenced by siRNA can inhibit the proliferation and the invasive potential of Jurkat cells remarkably.</p>

Expressions of vascular endothelial growth factor and cyclooxygenase-2 in patients with multiple myeloma and its significance / 中国实验血液学杂志

This study was aimed to investigate the expressions of vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) in patients with multiple myeloma (MM) and its clinical significance. Expression of VEGF was detected by enzyme linked immunosorbent assay (ELISA) and the level of COX-2 was detected by Western blot. The results showed that the serum VEGF level of multiple myeloma patients (365.34 +/- 65.63 pg/ml) was higher than that in the normal persons (122.52 +/- 39.29 pg/ml) (p < 0.05); the serum VEGF level of patients at advanced stage (395.07 +/- 54.90) pg/ml was higher than those at stable stage (300.33 +/- 44.22) pg/ml (p < 0.05). The serum Cox-2 positive rate in the patients (31%) was higher than that in normal persons (0%) (p < 0.01); the serum Cox-2 positive rate in the patients at advanced stage (50%) was higher than those at stable stage (21%) (p < 0.01). It is concluded that VEGF and COX-2 may play an important role in the pathogenesis and development of multiple myeloma, they can be used to evaluate the status of patients with MM.

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>

Characterization and functional studies of vWF A3 domain monoclonal antibodies that inhibit binding of vWF to collagen / 中华血液学杂志

<p><b>OBJECTIVE</b>To prepare anti-von Willebrand factor A3 (vWF-A3) domain monoclonal antibodies(mAbs) which block vWF-A3 binding to collagen, and characterize their biochemical properties and functions.</p><p><b>METHODS</b>BALB/c mice were immunized with purified recombinant vWF-A3 protein (rvWF-A3). Murine anti-human vWF-A3 mAbs were developed by standard hybridoma technology and identified with ELISA. The recognition of the mAbs with rvWF -A3 and reduced human vWF was identified by Western-blot. The effect of mAbs on binding of purified human vWF to human placenta or calf skin collagen III was studied with collagen binding inhibition test.</p><p><b>RESULTS</b>A group of 30 murine anti-human vWF-A3 mAbs was obtained, from which 2 clones were identified as inhibitory ones and designated as SZ-123 and SZ-125. SZ-123 and SZ-125 could react specifically with human vWF and rvWF-A3 respectively, while neither of them reacted with rvWF-A1 and rvWF-A2. Western-blot showed that SZ-123 and SZ-125 could recognize a 27 x 10(3) band of rvWF-A3 and 2 reduced human vWF bands at 250 x 10(3) and 170 x 10(3). SZ-123 and SZ-125 not only inhibited the binding of purified human vWF (1.5 and 3.0 microg/ml) to human type III collagen and to calf skin collagen III in a dose dependent manner, but also inhibited the binding of plasma vWF from human, rhesus monkeys or Beagle dogs to the two collagens.</p><p><b>CONCLUSION</b>SZ-123 and SZ-125 are neutralizing mAbs against vWF-A3 domain and may have therapeutic potential as an antithrombotic agent.</p>

Effects of amiodarone on funny current I(f) channel gene expression in neonatal rat ventricular myocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analysis the effect of amiodarone on funny current (I(f)) and hyperpolarization-activated cation channel (HCN) gene expressions of the neonatal rat ventricular myocytes.</p><p><b>METHODS</b>Ventricular myocytes of 1 - 3 days-old rats were isolated and cultured. The cardiomyocytes were treated by amiodarone (0.01, 0.1, 1, 10, 100 micromol/L) for 3 hours or amiodaron (10 micromol/L) for 0, 0.5, 1, 3, 6 hours. The I(f) and HCN 1 - 4 gene expressions were measured through the whole-cell configuration of the patch-clamp technique and real-time quantitative polymerase chain reaction (real-time PCR) using SYBR Green PCR kit.</p><p><b>RESULTS</b>(1) HCN1, HCN2, HCN3 and HCN4 represented (0.23 +/- 0.01)%, (83.58 +/- 0.04)%, (0.79 +/- 0.01)% and (15.44 +/- 0.01)% of total HCN mRNA, respectively. (2) Amiodaron resulted in a dose-dependent I(f) [(3.1 +/- 0.9)%, (9.7 +/- 2.4)%, (36.7 +/- 5.8)%, (80.3 +/- 1.8)% and (85.9 +/- 3.1)%, respectively at -145 mV, IC(50) (1.32 +/- 0.28) micromol/L], HCN2 [(2.1 +/- 0.8)%, (8.9 +/- 3.6)%, (30.1 +/- 4.2)%, (78.3 +/- 3.6)% and (81.1 +/- 1.9)%, respectively] and HCN4 decrease [(0.5 +/- 0.2)%, (2.1 +/- 2.6)%, (8.8 +/- 3.2)%, (60.1 +/- 4.6)% and (59.6 +/- 6.5)%, respectively]. (3) Amiodaron (10 micromol/L) also induced a time-dependent I(f) [(1.1 +/- 0.1)%, (12.6 +/- 2.3)%, (80.6 +/- 2.2)% and (80.1 +/- 2.1)%, respectively], HCN2 [(1.0 +/- 0.1)%, (9.8 +/- 3.9)%, (82.9 +/- 4.6)% and (83.9 +/- 1.7)%, respectively] and HCN4 decrease [(0.1 +/- 0.1)%, (1.9 +/- 1.1)%, (59.4 +/- 7.8)% and (60.9 +/- 3.1)%, respectively]. However, HCN1 and HCN3 expressions were not affected by amiodaron treatment.</p><p><b>CONCLUSION</b>Current density of I(f) and the expression of HCN2 and HCN4 were decreased by amiodaron which might be the possible antiarrhythmic working mechanisms of amiodaron.</p>

Mutation of Arg723Gly in beta-myosin heavy chain gene in five Chinese families with hypertrophic cardiomyopathy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Hypertrophic cardiomyopathy (HCM) is a form of cardiomyopathy with an autosomal dominant inherited disease, which is caused by mutations in at least one of the sarcomeric protein genes. Mutations in the beta-myosin heavy chain (beta-MHC) are the most common cause of HCM. This study was to reveal the disease-causing gene mutations in Chinese population with HCM, and to analyze the correlation between the genotype and phenotype.</p><p><b>METHODS</b>The exons 3 to 26 of MYH7 were amplified by PCR, and the PCR products were sequenced in five non-kin HCM patients. A 17-year-old patient was detected to be an Arg723Gly mutation carrier. Then his family was gene-screened, and the correlation between genotype and phenotype was analyzed.</p><p><b>RESULTS</b>The mutation of Arg723Gly in a Chinese family with HCM was detected for the first time. With a C-G transversion in nucleotide 13,619 of the MYH7 gene, located at the essential light chain interacting region in S1, the replacement of arginine by glycine took place at amino acid residue 723. A two-dimensional echocardiogram showed moderate asymmetrical septal hypertrophy with left atria enlargement. There was no obstruction in the left ventricular outflow tract. In his family, a total of 13 individuals were diagnosed HCM and 5 of them were dead of congestive heart failure at a mean age of 66-year-old. Eight living members were all detected to carry the mutation, in which 3 developed progressive heart failure. Moreover, the heart function of the people evidently deteriorates when their age are older than 50. The mutation and the disease show co-separated.</p><p><b>CONCLUSION</b>The Arg723Gly mutation is a malignant type. In Chinese the mutation has the similar characters to the former report but has low degree malignant.</p>

Malignant hypertrophic cardiomyopathy caused by the Arg723Gly mutation in beta-myosin heavy chain gene in a Chinese pedigree / 中华心血管病杂志

<p><b>OBJECTIVE</b>Hypertrophic cardiomyopathy (HCM) is a genetically and phenotypically heterogeneous disease and an Arg723Gly mutation in beta-myosin heavy chain (beta-MHC) gene was found in 3 Spanish families with malignant HCM. We detected this gene mutation in 5 Chinese pedigrees with hypertensive cardiomyopathy.</p><p><b>METHODS</b>Five Chinese pedigrees with HCM and 80 age-matched normal control subjects were chosen for the study. The exons in the functional regions of the beta-MHC gene were amplified with PCR and the products were sequenced, genotype and phenotype analyzed.</p><p><b>RESULTS</b>Arg723Gly mutation was identified in exon 20 in one pedigree. In this pedigree, 13 out of 25 family members were diagnosed as HCM, 5 died of heart failure, all HCM patients in this pedigree had Arg723Gly mutation and 3 of them had NYHA III and 2 of them were diagnosed as HCM before the age of 20.</p><p><b>CONCLUSIONS</b>Arg723Gly mutation was also one of the main disease-causing genes in Chinese familial HCM. The mutation of Arg723Gly is a malignant phenotype as shown by early progressive heart failure development and poor prognosis in this pedigree with Arg723Gly mutation.</p>

A novel genetic defect in a Chinese family with inherited coagulation factor XIII deficiency / 中华血液学杂志

<p><b>OBJECTIVE</b>To identify the genetic defect of inherited coagulation factor (F) deficiency in a Chinese family and to explore its molecular mechanism.</p><p><b>METHODS</b>The activity and antigen of plasma F were measured by photometric test and enzyme-linked immunosorbent assay, and rocket-electrophoresis, respectively. All the exons and exon-intron boundaries of the FA subunit gene were amplified by PCR and then DNA sequencing was performed. Restriction endonuclease analysis was used for the PCR products of the family members and 80 healthy donors to exclude gene polymorphism.</p><p><b>RESULTS</b>Rapid dissolution of the proband's fibrin clot occurred within 30 minutes, and antigen of his plasma F was significantly decreased, two compound heterozygous missense mutations (a C to T transition at nucleotide 177,246 which caused Arg703Trp, and a A to G transition at nucleotide 177,286 which caused His716Arg) in exon 15 of FA subunit gene were found. The possibility of gene polymorphism was excluded by restriction endonuclease analysing. Each of these two missense mutations was respectively found in his mother and father. Molecular modeling based on 3D crystallographic data predicted that the mutant protein decreased stability and was likely to be rapidly degraded.</p><p><b>CONCLUSIONS</b>The inherited F deficiency in the Chinese family is caused by two compound heterozygous missense mutations-Arg703Trp and His716Arg in the FA subunit, which to our knowledge, are reported for the first time.</p>

Determination of the ADAMTS13 antigen and its activity in TTP patients and carriers / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the antigen levels and activity of von Willebrand factor cleaving protease ADAMTS13 in thrombotic thrombocytopenic purpura (TTP) patients and carriers.</p><p><b>METHODS</b>28 samples from 13 TTP patients and 10 samples from the carriers were examined. The activity of ADAMTS13 was measured by residue collagen binding assay, and antigen by a newly developed sandwich ELISA.</p><p><b>RESULTS</b>The mean ADAMTS13 level in Chinese normal controls (CN) was (600.93 +/- 145.36) mU/ml (n = 26) comparable to the level (1000 mU/ml) in pooled normal Caucasian plasma, and the activity was (74.79 +/- 11.81)%. Both the antigen level and activity of ADAMTS13 in congenital TTP patients either before plasma exchange (pre-PE) or interval relapse were quite lower than those in normal control, but were increased after PE (post-PE). The antigen was (331.40 +/- 109.85) mU/ml (P < 0.01, n = 10), and activity was (66.79 +/- 12.82)% (P > 0.05). The ADAMTS13 levels pre-PE in idiopathic TTP was (98.7 +/- 82.08) mU/ml (n = 11, P < 0.01), and that post-PE was up to (449.4 +/- 232.33) mU/ml (P < 0.01, n = 10). The activity of ADAMTS13 in patients pre-PE and post-PE were (22.23 +/- 19.07)% (P < 0.01) and (60.92 +/- 22.33)% (P > 0.05) respectively. In a secondary TTP patient the ADAMTS13 antigen was much higher than that in CN, and the activity was 6.00%.</p><p><b>CONCLUSION</b>The antigen and activity of ADAMTS13 in most TTP patients pre-PE are deficient, and these two indices in most TTP patients are paralleled. The reason for ADAMTS13 deficiency is congenital shortage or clearance by immune system, but it is unknown that why in some patients the ADAMTS13 antigen is extremely high but its activity is quite low.</p>

The effect of on VEGF-C cDNA transfection on NB4 cell proliferation, differentiation and resistance to apoptosis / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the biological effect on NB4 cells proliferation, all-trans retinoic acid (ATRA) inducing differentiation and resistance to apoptosis by vascular endothelial growth factor (VEGF)-C cDNA transfection.</p><p><b>METHODS</b>The recombinant eukaryotic expression plasmid pcDNA3.1-VEGF-C and the vacant pcDNA3.1 vector were introduced separately into NB4 cells by lipofectamine mediation. The positive clones were screened by G418 and identified by reverse transcriptase-PCR (RT-PCR) and Western blotting. The proliferation capacity of NB4/VEGF-C cells was analysed by MTT assay and colony forming assay in vitro. After NB4/VEGF-C cells were induced by ATRA, the expression level of C/EBPalpha gene, CD11b on cells surface and morphological alteration were analysed by real-time quantitative PCR (RQ-PCR), flow cytometry (FCM), and Wright-Giemsa staining, respectively. FCM Annexin V-FITC/PI dual labeling technique was performed to investigate the etoposide (Vp16) induced NB4/VEGF-C cells apoptosis and bcl-2 gene expression level in these cells was analysed by RQ-PCR. The NB4/pcDNA3.1 cells was used as control in the above experiments.</p><p><b>RESULTS</b>A stable NB4 cell line that secrets VEGF-C and its control lines were established. The proliferation capacity of the former was stronger than that of the latter. The expression level of C/EBPalpha gene of NB4/VEGF-C cells on ATRA treatment was only 1/32 that of NB4/pcDNA3.1 cells. The CD11b level and the degree of differentiation of NB4/VEGF-C were weaker than that of NB4/pcDNA3.1 cells. The percentage of apoptotic NB4/VEGF-C cells induced by Vp16 [(7.20 +/- 2.52)%] was significantly lower than that of NB4/pcDNA3.1 cells [(16.07 +/- 3.58)%] (P = 0.005), but the bcl-2 gene expression level of NB4/VEGF-C cells is 2.28-fold that of NB4/pcDNA3.1 cells.</p><p><b>CONCLUSION</b>The VEGF-C via VEGFR-3 signaling pathway could promote the proliferation of leukemic cells by autocrine pathway and inhibit the cell differentiation mediated by ATRA and chemotherapy-induced apoptosis. VEGF-C/VEGFR-3 signaling loops might play an important role in disease progression and be potential therapeutic target for the treatment of leukemias.</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.

Identification of two novel mutations in ADAMTS13 gene in a patient with hereditary thrombotic thrombocytopenic purpura / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the gene mutations of ADAMTS13 in a highly suspected hereditary thrombocytopenic purpura (TTP) patient, and then make a progressive diagnosis and adjust the plan of therapy.</p><p><b>METHODS</b>ADAMTS13 activity and inhibitor were determined by residual-collagen binding assay during several episodes. Genomic DNA extracted from the proband's peripheral blood was used for amplification of 29 exons and exon/intron boundaries of ADAMTS13 by PCR. The PCR products were screened by direct sequencing and the gene alterations were further confirmed by direct sequencing in her family members.</p><p><b>RESULT</b>The activity of the proband's ADAMTS13 was significantly reduced while no inhibitor was found. Two novel missense mutations were found in the TSPI repeated motif domain of ADAMTS13. In both mutations, thymine substituted for cytidine, resulting in the substitution of leucine for serine in nt 2708, exon 21 (codon S903L), and tryptophan for arginine in nt 3283, exon 25(codon R1095W). These two mutations were revealed as each heterozygote in the proband's parents.</p><p><b>CONCLUSION</b>The deficiency of ADAMTS13 caused by two homozygote missense mutations might be responsible for episode of this TTP patient.</p>