Kinase domain insert containing receptor promoter controlled suicide gene system selectively kills human umbilical vein endothelial cells

AIM： To study the selective killing of human umbilical vein endothelial cells （HUVECs） by a double suicide gene under the regulation of a kinase domain insert containing receptor （KDR） promoter and mediated by an adenoviral gene vector. METHODS： Human KDR promoter was cloned by polymerase chain reaction （PCR）, and two recombinant adenoviral plasmids pAdKDR-CdgIyTK, pAdCMV-CDglyTK were constructed according to a two-step transformation protocol. These two newly constructed plasmids were then transfected into 293 packaging cells to grow adenovirus, which were further multiplied and purified. HUVECs and LoVo cells were infected with either of the two resultant recombinant adenoviruses （AdKDR-CDglyTK and AdCMV-CDglyTK） respectively, and the infection rates were estimated by detection of green fluorescent protein （GFP） expression. Infected cells were cultured in culture media containing different concentrations of 5-fiuoroo/tosine （5-FC） and ganciclovir （GCV）, and the killing effects were measured. RESULTS： The two recombinant adenoviral plasmids pAdKDR-CdglyTK, pAdCMV-CDglyTK were successfully constructed and transfected into 293 cells. The resultant recombinant adenoviruses infected cells caused similar infection rates; and the infected cells exhibited different sensitivity to the prodrugs： HUVECs infected with AdCMV-CDglyTK and LoVo cells infected with AdCMVo CDglyTK were highly sensitive to the prodrugs, and HUVECs infected with AdKDR-CDglyTK were similarly sensitive but significantly more sensitive than the LoVo cells infected with AdKDR-CdglyTK （P 〈 0.001）. CONCLUSION： Selective killing of HUVECs may be achieved by gene transfer of double suicide gene under the regulation of the KDR promoter. This finding may provide an optional way to target gene therapy of malignant tumors by abrogation of tumor blood vessels.

Myeloid neoplasm with eosinophilia and rearrangement of plateletderived growth factor receptor beta gene in children: Two case reports

BACKGROUND Myeloid neoplasm(MN)with eosinophilia and rearrangement of platelet-derived growth factor receptor beta(PDGFRB)shows a good therapeutic response to imatinib in adults.MN is rarely found in children,and the efficacy of imatinib on pediatric patients remain unclear.CASE SUMMARY We report 2 pediatric cases diagnosed with MN with eosinophilia and PDGFRB rearrangement who were treated with imatinib.Case 1 was a 1-year-old girl admitted to the hospital because of“abdominal distension with hyperleukocytosis for 3 mo”.She had leukocytosis,anemia,and eosinophilia(the absolute eosinophil count(AEC)was 8960/μL),and her fluorescence in situ hybridization(FISH)test revealed that PDGFRB rearrangement was detected in 70%of 500 interphase cells.Case 2 was a 2-year-old girl admitted to the hospital because of“recurrent fever and rashes for 1 mo”.Her blood cell count showed an AEC of 3540/μL.The FISH test revealed that PDGFRB rearrangement was detected in 71%of 500 interphase cells.Both patients were diagnosed as MN with eosinophilia and PDGFRB rearrangement.Imatinib was added into their treatment regimen.As expected,complete hematologic remission was achieved after 1 mo of treatment,and symptoms disappeared.CONCLUSION Although MN with eosinophilia and PDGFRB rearrangement usually occurs in adults,it can be found in children.The therapeutic benefits of imatinib in these 2 pediatric patients were consistent with its reported effects in adult patients.

The Patatin-Containing Phospholipase A pPLAIIα Modulates Oxylipin Formation and Water Loss in Arabidopsis thaliana

The patatin-related phospholipase A （pPLA） hydrolyzes membrane glycerolipids to produce monoacyl compounds and free fatty acids. Phospholipids are cleaved by pPLAIIα at the sn-1 and sn-2 positions, and galactolipids, including those containing oxophytodienoic acids, can also serve as substrates. Ablation of pPLAIIα decreased lysophosphatidylcholine and lysophosphatidylethanolamine levels, but increased free linolenic acid. pPLAIIα-deficient plants displayed a higher level of jasmonic acid and methyl jasmonate, as well as the oxylipin-biosynthetic intermediates 13-hydroperoxylinolenic acid and 12-oxophytodienoic acid than wild-type （WT） plants. The expression of genes involved in oxylipin production was also higher in the pPLAIlec-deficient mutant than in WT plants. The mutant plants lost water more quickly than WT plants. The stomata of WT and mutant plants responded similarly to abscisic acid. In response to desiccation, the mutant and WT leaves produced abscisic acid at the same rate, but, after 4 h of desiccation, the jasmonic acid level was much higher in mutant than WT leaves. These results indicate that pPLAIIα negatively regulates oxylipin production and suggest a role in the removal of oxidatively modified fatty acids from membranes.

A pruning algorithm with L_(1/2) regularizer for extreme learning machine

Compared with traditional learning methods such as the back propagation(BP)method,extreme learning machine provides much faster learning speed and needs less human intervention,and thus has been widely used.In this paper we combine the L1/2regularization method with extreme learning machine to prune extreme learning machine.A variable learning coefcient is employed to prevent too large a learning increment.A numerical experiment demonstrates that a network pruned by L1/2regularization has fewer hidden nodes but provides better performance than both the original network and the network pruned by L2regularization.