Establishing the Blood Donor Deferral Criterion in TP ELISA Test / 中国实验血液学杂志

OBJECTIVE@#To Establish the shielding threshold value of TP antibody ELISA for unpaid blood donors, so as to shield true positive blood donors from returning to team management.@*METHODS@#The real serological status of 517 samples with anti-TP ELISA reactivity was determined by confirmation test of Treponema pallidum particle agglutination (TPPA). The shielding threshold of TP antibody was preliminarily determined by using 99% specificity of ROC and 95% positive predictive value of percentile method, respectively. 283 TP antibody reactivity specimens routinely tested in our laboratory were selected to determine the applicability of the initial shielding values obtained by the two methods, and finally to determine the shielding threshold values of TP antibody donors.@*RESULTS@#The specific S/CO values of reagent A 99% were 13.33-16.18, that of reagent B 99% was 6.34, that of reagent B 99% was 13.17-19.85, and that of 95% was 6.62. Empirical evidence: 99% specific threshold shielding true positive rates of reagents A and B were 100%, 95% positive expected value shielding true positive rates were 98.4%, 99%. Final determination of 99% specific shielding threshold as a low value of blood donors shielding threshold. The shielding limits of reagent A and B were 13.33 and 13.17.@*CONCLUSION@#The shielding threshold of TP antibody ELISA for blood donors established in this study can help to reduce the number of blood donors returning to team management.

Evaluation of the Cutoff of Anti-HCV Antibody Enzyme-Linked Immunosorbent Assay in 7 Blood Station Laboratories / 中国实验血液学杂志

OBJECTIVE@#To evaluate the necessity and suitability of the anti-HCV ELISA teot gray zone setted up by 7 blood station laboratories.@*METHODS@#7 blood station laboratories were coded as 1, 2, 3, 4, 5, 6 and 7 respectively; 8 kinds of ELISA reagents were coded as A, B, C, D, E, F, G and H respectively. 1 or 2 of 8 ELISA reagents produced by different manufactories were used to detect the anti-HCV in specimens of same group by 7 blood station laboratories; the Westen blot was used to detect the specimens with difference of detected results so as to difine the serological status of specimens. The true positive rate of specimens detected by laboratories and gray zone-comfirined positive rate of specimens were accounted so as to analyze the necessity of setting up the gray zone for anti-HCV ELISA test of 7 blood station laboratories; the optimal cut-off value for anti-HCV ELISA test was determined in 7 blood station laborafories by ROC curve and the changes of sensitivity and specificity of 3 different cut-off value(laboratory work cut-off value, manifactory-recommended cun-off value and optimal cut-off value) were compared so as to analyze the suitability of gray zone for anti-HCV ELISA test in 7 blood station laboratories.@*RESULTS@#The true positive rate detected by 7 blood station laboratories, out of which coded 1 laboratory used 2 kinds of coded A, B reagents was 95.40%(1A), 99.23% (1B), 94.25% (2C), 96.17% (3D), 98.08% (4E), 96.93% (5F), 97.32%(6G) and 93.10%(7H). Except for 2C(94.25%) and 7H(93.10%), the true positive rate detected by laboratoies which not sutted up gray zone, the gray zone-con-firmed positive rate in 6 blood station laboratories setted up gray zone: was 0.00%, 0.00%, 21.43%, 0.00%, 0.00%, 0.00% and 38.89%. The comparison of 3 different cut-off valuces by ROC curve showed that the anti-HCV cut-off values in 5 laboratories(1B, 2C, 4E, 5F and 6G) were as follows: optimal cut-off value＞manufactory recommeded cut-off value＞laboratory work cut-off value, thus use of manufactory-recommeded cut-off value abreadly has reached the high sensitivity requinements for laboratory screening; however, the optimal cut-off value in laboratories 1A, 3B and 7H, thas the appropriate gray zone should be used. In 6 laboratories setting up gray zone, the gensitivity in 3D, 7H laboratories only a little improved (1.60% and 2.70% raspectively) in Eamparison between laboratory work cut-off value and manufactorg-recommeded cut-off value; moreover, the sensitivity in other laboratories not is changed, but the specificity decreased (0.20%-0.50%).@*CONCLUSION@#In addition to setting up the appropriate gray zone in laboratories 1A, 3D and 5H, the gray zone in other laboratories may be cancelled. Even in the same laboratory, the setting up the gray zone also should be scientifically assessed, the same scale cannot be blindly used, thus appropniate strategies should be established.

Algorithm of digital demodulation and filtering in MRI spectrometers / 中国医疗器械杂志

In the design of RF receiver of the digital MRI spectrometer console, a digital demodulation and filtering algorithm is presented in this thesis. The MR signals are firstly converted to digital signals by the A/D converter, and then quadrature-demodulated from high frequency carrier wave. The CIC filter, half-band filter and linear phase FIR filter are designed to process the cascaded filtering and decimation of the demodulated signals. This method achieves a satisfying processing speed and filtering effect, and also reduces the data size obviously. The experiment based on the permanent magnetism resonance imaging system proves its effectiveness and practicability.

Finite element method-based optimal design of MRI permanent magnet / 中国医疗器械杂志

This paper presents a simulation method to study and improve the technology of designing magnets. With the finite element method, it analyzes the magnetic field distribution of the magnet model constructed by CAD software. Based on the distribution characteristics of magnetic field, the redundancy parts of the magnet configuration are removed accurately. The experiment results show that this method can significantly lighten the magnet.

Design of a digital spectrometer for the MRI system / 中国医疗器械杂志

A spectrometer is one of the most important parts in a Magnetic Resonance Imaging (MRI) system. This paper describes the design of a digital MRI spectrometer. It is constructed on a PXI platform with several data acquisition boards and a high-resolution timing board. All functions of a MRI spectrometer are realized by the specially- designed software. The software architecture and its implementing details are discussed and experimental results are introduced.

Research on designing MRI permanent magnet / 中国医疗器械杂志

Based on the theory of magnet circuits, the paper introduces the process of designing MRI (Magnetic Resonance Imaging) permanent magnet. The measurement of magnet properties is improved by simulation technology. In order to increase the magnetic field homogeneity. We have designed a shim-loop and a trapeziform shim-board to optimize the magnetic field distribution. The results of both simulation analysis and experiments show that the innovative design improves magnetic field properties significantly and the magnet structure accords with the technology requirements.

Cloning and expression of human interleukin-26 in Escherichia coli / 生物工程学报

To clone human interleukin-26 (hIL-26) and express it in E. coli efficiently. Two pairs of primers were synthesized according to the hIL-26 gene reported on GenBank. The hIL-26 gene was cloned by nest PCR following the first round RT-PCR from human peripherial blood monocytes total RNA, and then the PCR product was cloned into pMD18-T vector. Colony PCR, restriction analysis and sequence analysis showed that the gene cloned was the same as the reported hIL-26. The recombinant was cut with BamHI and EcoR I to obtain the hIL-26 fragment, and then the fragment was inserted into pBV220 which was cut with the same enzymes. The recombinant expression vector was induced to express hIL-26 at 42 degrees C, SDS-PAGE analysis showed that the recombinant protein accounted for up to 20% of the whole protein of E. coli, and the protein was also confirmed by Western blotting. Purity of the protein was found to be above 90% after purified with molecular sieve. After renaturalized with glutathione buffer, the promoting effect of it on the production of IFN-y in PBMC was detected by RT-PCR. A recombinant bacterial strain for expressing hIL-26 with biological activity was constructed successfully.

Correlation of thrombosis with increased platelet turnover in essential thrombocythemia / 中国实验血液学杂志

This study was aimed to investigate the correlation of thrombosis with increased platelet turnover in essential thrombocythemia. According to presence or absence of thrombosis, 26 patients with ET were divided into two groups. Reticulated platelets (RP) were measured by flow cytometry and 26 healthy volunteers were selected as healthy controls. The ET patients with thrombosis were treated with hydroxyurea and interferon-alpha. The results demonstrated that the ET patients with thrombotic events had a significantly higher RP percentage (14.8% +/- 7.2%) than that in both asymptomatic ET patients (4.5% +/- 2.3%) and normal control (3.3% +/- 1.5%), (P < 0.05); the RP percentage in asymptomatic ET patients did not differ significantly from controls. ET patients with thrombosis also had a significantly higher absolute RP (ARP) count than those in ET patients without thrombosis [(176 +/- 37) x 10(9)/L vs (46 +/- 12) x 10(9)/L]. The ET patients with thrombosis were successfully treated with hydroxyurea plus INF-alpha, the RP percentage and ARP counts obviously reduced. In conclusion, when the ET patients had thrombotic events, those patients had a significantly higher RP percentage and ARP compared with patients without thrombosis and healthy controls. The ET patients with thrombosis were successfully treated with hydroxyurea plus INF-alpha.

A rapid method of eddy current compensation in magnetic resonance imaging systems / 中国医疗器械杂志

Imaging objects are spatially encoded by gradient magnetic fields in magnetic resonance imaging systems. The eddy current caused by rapid switches of gradient fields will result in artifacts in the images. A method of eddy current compensation based on pre-emphasis of gradient current is presented in this thesis. The compensation parameters are acquired rapidly utilizing Faraday's induction theorem and data fitting method. The experiments prove that the method is efficient for reduction of the debugging time and for the improvement of the image quality.