A positioning error measurement method in radiotherapy based on 3D visualization / 中国医疗器械杂志

The positioning error in radiotherapy is one of the most important factors that influence the location precision of the tumor. Based on the CT-on-rails technology, this paper describes the research on measuring the positioning error in radiotherapy by comparing the planning CT images with the treatment CT images using 3-dimension (3D) methods. It can help doctors to measure positioning errors more accurately than 2D methods. It also supports the powerful 3D interaction such as drag-dropping, rotating and picking-up the object, so that doctors can visualize and measure the positioning errors intuitively.

Detection of Schistosomia japonicum 5D gene by polymerase chain reaction and genechip technique / 中华流行病学杂志

<p><b>OBJECTIVE</b>In order to develop the diagnostic genechip for specific detection of Schistosoma japonicum (Chinese mainland strain).</p><p><b>METHODS</b>Probe and primers were designed based on the Schistosoma japonicum 5D gene encoding an immunogenic miracidial antigen. The probe for the conservative and specific gene sequence was spotted onto the specially treated glass slides by pin-based spotting robot Pixsys 5500 and was employed to make genechips. A polymerase chain reaction (PCR) protocol was designed to effectively amplify the 5D gene fragment containing the probe sequence from cercaria, egg, adult worm and infected Oncomelania DNA as well as other flukes DNA, respectively. After 35 cycles by PCR, the products were then labeled with fluorescent Cy3-labeled primer, using dissymmetrical PCR. The labeled PCR products of the target genes were hybridized to the diagnostic genechips for detection of Schistosoma japonicum and a fluorescent scanner (ScanArray 3000) was used to observe and record the hybridization signals.</p><p><b>RESULTS</b>The result obtained from the study showed that a 262 bp DNA fragment was amplified from cercaria, egg and adult worm with the designed primers and enable the genechip be applied to detect a single cercaria, egg and adult worm. When the genechip was used to detect Clonorchis sinensis, Fasciolopsis busk, and Paragonimus westermani DNA, the results showed negative, indicating that the genechip had good specificity.</p><p><b>CONCLUSION</b>The genchip technique for detection of Schistosoma japonicum was established successfully and having the characteristics of high sensitivity and specificity.</p>

Expression, purification and serological reactivity of a chimeric antigen of GRA6 with P30 from Toxoplasma gondii / 生物工程学报

Major surface protein (p30) and Dense Granule Antigen GRA6 of Toxoplasma gondii have good antigenicity, and could be used for detection of IgM against Toxoplasma gondii. GRA6 may complement P30 to reach more high sensitivity for detection of antibodies to Toxoplasma gondii, so, we try to express the chimeric protein of GRA6 and P30 by genetic engineering, identify its antignenicity and use for developing diagnosis reagent. Antigenic domains of p30 and GRA6 of Toxoplasma gondii were screened by analyzing their sequences using the software ANTHEWIN. Two DNA fragments encoding respectively antigenic domains of p30 and GRA6 were cloned, they were inserted into the same expression vector pET28a( + ) and expressed as a chimeric protein in Escherichia coli. BL21(DE3), the expressed chimeric protein of p30 with GRA6 in a form of inclusion body was about 25% of total proteins of E. coli. BL21(DE3). The inclusion body was washed once with 0.5% Triton X-100 and dissolved with 0.5% SKL, after renaturation by gradient dialysis, the recombinant protein was purified by DEAE-Sepharose FF cation column and then detected with 12% SDS-PAGE, it exists mainly in the eluted peak with 300 mmol/L NaCl and has high purity. By using enzyme-linked immunosorbent assay (ELISA), the recombinant protein was examined for reactivity with immunoglobulin M (IgM) antibodies in 6 sera from patients infected with Toxoplasma gondii ., it was reactive with all the 6 sera but not with sera from normal people, these results showed that the recombinant chimeric antigen has good antigenicity and specificity and could be used for detection of IgM against Toxoplasma gondii. The expressed chimeric protein could be used for epidemic investigation of Toxoplasma gondii, blood donor screening, especially for detection of pregnant women, and is of great significance in prevention of Toxoplasma gondii infection.

Expression of TPO mimetic peptide chimeric proteins with human IgG1 Fc fragments and their biological characters / 生物工程学报

Many antineoplastic agents can cause myelosuppression and thrombocytopenia. Thrombopoietin (TPO) is believed to be the major cytokine affecting the proliferation and maturation of megakaryocytes and increasing circulating platelet levels. We have designed and synthesized a TPO mimetic peptide, it can increase circulating platelet levels in vivo. For increasing half-life and forming dimer, the peptide was expressed as chimeric proteins with human IgG1 Fc fragments. The cDNA of TPO mimetic peptide was synthesized chemically and linked respectively to 5' terminus of human IgG1 Fc cDNA fragments in various length (Fc1: Fc 5' 648 bp; Fc2: Fc 5' 270 bp; Fc3: Fc 5' 267 bp; Fc4: Fc 5' 90 bp), and cloned into expression plasmid pET28a (+) for constructing four recombinant plasmids. By transforming the four recombinant plasmids into E. coli. BL21 (DE3) respectively, we got 3 kinds of engineered E. coli which express TPO + Fc chimeric proteins(28 kD TPO + Fc1, 12 kD TPO + Fc2 and 12 kD TPO + Fc3) at high level respectively, the expressed proteins were purified with DEAE-Sepharose FF and S-Sepharose FF column. The bioactivities of the expressed chimeric proteins(TPO + Fc1, TPO + Fc2 and TPO + Fc3), TPO mimetic peptide, and PEG4000 coupled TPO mimetic peptide were evaluated with Ba/F3-mp1 in vitro and with carboplatin-induced thrombocytopenia mice in vivo, the expressed chimeric proteins have higher activity than TPO mimetic peptide both in vitro and in vivo, the EC50 on Ba/F3-mp1 cells were 13, 10, 10, 50, and 25 nmol/L respectively, all of them can increase circulating platelet counts. Their imol/Lunogenicity were valuated in mice, none of them can elicit mice to produce antibodies to TPO mimetic peptide, meanwhile three TPO + Fc chimeric proteins can elicit mice to produce antibodies to human IgG1 Fc. These studies have laid basis for production of TPO mimetic peptide by genetic engineering.