A novel modi cation of real-time AS-qPCR by using locked nucleic acid-modified oligonucleotide probe as wild type allele amplification blockers for quantitative detection of the JAK2 V617F mutation / 中华血液学杂志

<p><b>OBJECTIVE</b>To develop a novel real-time PCR for sensitively quantitative detection of JAK2 V617F allele burden in peripheral blood.</p><p><b>METHODS</b>Based on the real-time allele-specific PCR (AS-qPCR), the locked nucleic acid (LNA)-modified oligonucleotide probe was used for selectively blocking amplification of wild-type alleles in AS-qPCR, and then a novel AS-LNA-qPCR method was established. The percentages of sample JAK2 V617F alleles were directly calculated by its threshold cycle (Ct) values according to the standard curve which generated by JAK2 V617F alleles with its Ct values. We validated intra- and inter-assay variability for quantifying JAK2 V617F. We also assayed 623 apparent healthy donors by our method to validate its clinical application value.</p><p><b>RESULTS</b>The quantitative lower limit of this method for JAK2 V617F was 0.01%, and the intra- and inter-assay average variability for quantifying percentage of JAK2 V617F in total DNA was 6.3% and 8.6%, respectively. Nineteen JAK2 V617F-positive individuals were identified using AS-LNA-qPCR in blood of 623 apparently healthy donors, and the range of percentages of JAK2 V617F alleles were 0.01%-5.49%.</p><p><b>CONCLUSION</b>The AS-LNA-qPCR with highly sensitive and reproducible quantification of JAK2 V617F mutant burden can be used clinically for diagnosis as well as evaluation of disease prognosis and efficacy of therapy in patients with myeloproliferative neoplasms.</p>

Detection of JAK2V617F mutation rate by real-time fluorescent quantitative PCR using allele specific primer and TaqMan-MGB probe for dual inhibiting amplification of wild type alleles / 中国实验血液学杂志

This study was purposed to develop a real-time PCR assay for sensitive quantification of JAK2V617F allele burden in peripheral blood and to evaluate the clinical value of this method. Both allele-specific mutant reverse primer and wild-type TaqMan-MGB probe were used for dual-inhibiting amplification of wild-type alleles in a real-time PCR, and then the JAK2V617F mutant alleles were amplified specially. The standard curve for quantification of JAK2V617F was established by percentages of JAK2V617F alleles with threshold cycle (Ct) values in a real-time PCR. Furthermore, 89 apparent healthy donors were tested by this method. The results showed that the quantitative lower limit of this method for JAK2V617F was 0.1%, and the intra- and inter-assay average variability for quantifying percentage of JAK2V617F in total DNA was 4.1% and 6.1%, respectively. Two JAK2V617F-positive individuals were identified (the percentage of JAK2V617F alleles were 0.64% and 0.98%, respectively) using this method in blood from 89 apparently healthy donors. It is concluded that the developed method with highly sensitive and reproducible quantification of JAK2V617F mutant burden can be used clinically for diagnosis and evaluation of disease prognosis and efficacy of therapy in patients with myeloproliferative neoplasms. Moreover, this technique can be also used for quantitative detection of variety of single nucleotide mutation.

Cyclooxygenase inhibitors in some dietary vegetables inhibit platelet aggregation function induced by arachidonic acid / 中国实验血液学杂志

The study was purposed to investigate whether the cyclooxygenase inhibitors from some dietary vegetables can inhibit platelet aggregation function by the arachidonic acid (AA). The vegetable juice was mixed with platelet rich plasma (PRP), and asprin was used as positive control. The maximum ratio of platelet aggregation induced by AA was measured on the aggregometer; heme and cyclooxygenase-1 (COX(1)) or cyclooxygenase-2 (COX(2)) were added to test tubes containing COX reaction buffer, the mixture was vortex-mixed and exposed to aspirin or vegetable juice, followed by addition of AA and then hydrochloric acid (1 mol/L) was added to stop the COX reaction, followed by chemical reduction with stannous chloride solution. The concentration of COX inhibitors was detected by the enzyme immunoassay kit; vegetable juice (aspirin as positive control) was mixed with whole blood, which was followed by the addition of AA, and then the reaction was stopped by adding indomethacin, centrifuged, then the supernatant was collected, and the plasma thromboxane B(2) (TXB(2)) was measured by radioimmunoassay. The results showed that spinach juice, garlic bolt juice, blanched garlic leave juice and Chinese leek juice could inhibit by 80% human platelet aggregation induced by AA. 4 kinds of vegetables were all found a certain amount of cyclooxygenase inhibitors, which COX(1) and COX(2) inhibitor concentrations of spinach were higher than that of aspirin; 4 vegetable juice could significantly reduce the human plasma concentrations of TXB(2) induced by AA (p < 0.05). It is concluded that 4 kinds of raw vegetables containing cyclooxygenase inhibitors inhibit the production of TXA(2) and thus hinder platelet aggregation. Raw spinach, garlic bolt, blanched garlic and chinese leek inhibit significantly AA-induced human platelet aggregation in vitro. 4 kinds of vegetables may have a good potential perspective of anti-platelet aggregation therapy or prevention of thrombosis.