Rapid detection of PAH gene mutations in Chinese people.

BACKGROUND: Phenylketonuria (PKU) is an autosomal recessive genetic disease, caused by the phenylalanine hydroxylase (PAH) deficiency in the metabolic pathway, which prevents phenylalanine from being converted into tyrosine, leading to a large amount of phenylalanine discharged from the urine. Therefore, it is necessary to establish a simple, fast, accurate and reliable PKU molecular diagnostic method for clinical diagnosis. METHODS: We established a novel diagnostic method by combining a single-tube multiplex PCR technique with molecular hybridization technique. The method was verified by DNA sequencing technology. The established new technology successfully detected 9 common PAH gene mutations in the Chinese population. RESULTS: Double-blind analysis indicated that the diagnostic accuracy and specificity of the PKU sample were all 100%. Frequencies of single mutation R111X, R176X, Ex6-96A, R241C, R243Q, R252Q, Y356X, V399 V and R413P genotypes were 8, 0.5, 16.5, 1.5, 27, 4.5, 13, 10.5, 8.5% respectively. CONCLUSIONS: The established method of combing single-tube multiplex PCR with molecular hybridization technology can accurately and rapidly detect PAH gene mutations in Chinese and is suitable for screening of large PKU populations with clinical samples.

A novel anti-tissue factor monoclonal antibody with anticoagulant potency derived from synthesized multiple antigenic peptide through blocking FX combination with TF.

Tissue factor (TF) has been implicated in the pathogenesis of various thrombotic disorders. Monoclonal antibodies (mAb) that specifically target TF may have potential as antithrombotic therapy. We designed a unique TF peptide (TFP) that was specific for the binding site to factor X (FX). This peptide was used to develop TF mAb that block the coagulation cascade by interfering with the combination of FX with the TF/FVIIa complex. Chemically synthesized TFP coupled to polylysine matrix was used as multiple antigenic peptide (TF-MAP) and this was used to immunize Balb/c mice for the preparation of hybridomas. One hybridoma cell line released an antibody, named TF4A12, which had high anticoagulant potency (by dilute prothrombin time assay). Western blotting showed that TF4A12 could bind TF-MAP and the soluble TF extracellular domain (sTF(1-219)). Results of FX activation assay and amidolytic activity assay showed that the anticoagulant ability of TF4A12 is due to blocking FX, but not FVII, binding to TF. Our study identified an efficient method of developing TF mAb that could block the coagulation cascade.

[Cloning, expression and biological characterization of hTFPI-2 gene].

OBJECTIVE: To clone the human tissue factor pathway inhibitor-2 (hTFPI-2) gene and express it by using prokaryotic expression system. METHODS: The hTFPI-2 coding region was obtained by RT-PCR from human placenta total RNA. The coding fragment was then inserted into prokaryotic expression vector pET19b and expressed in E. coli BL21 by IPTG induction. The produced inclusion bodies were dissolved by denaturalizing chemicals, purified by ion exchange chromatograph, and refolded in air to form proper disulfide bonds. Chromogenic and gelatin zymography methods were used to evaluate the inhibiting effects of hTFPI-2 on trypsin, plasmin and MMPs individually. The inhibitory activity of hTFPI-2 on fabrisarcoma was investigated by matrigel. RESULTS: The coding fragment of hTFPI-2 was cloned successfully and the protein was expressed as inclusion bodies which account for 20% - 30% of total host protein. The refolded hTFPI-2 could inhibit the invasive ability of fibrisarcoma HT-1080 as well as activity of plasmin, trypsin and MMPs. CONCLUSIONS: The activated hTFPI-2 is obtained by using prokaryotic expressed system effectively.