Biomedical subjects

Xue-Mei Sun

Publications and source records attributed to Xue-Mei Sun.

9 recordsLinked to original sources

PubMed2006

[Plant sulfate assimilation and regulation of the activity of related enzymes under cadmium stress].

The complexation and sequestration of heavy metal ions (e.g. Cd) by the cysteine-rich polypeptides known as phytochelatins (PC) are thought to confer heavy metal hyperaccumulation and tolerance in some plant species. PC is synthesized enzymatically from glutathione. The tripeptide glutathione is a product of primary sulfur metabolism. A variety of enzymes or proteins are involved in sulfur assimilation including sulfate transporters (STs), ATP sulfurylase (ATPS), APS reductase (APSR), sulfite reductase (SiR), glutathione synthetase (GS) and phytochelatin synthesis (PCS). These enzymes or proteins are upstream-regulated by Cd at either the metabolic or the genetic level under metal stress. Increasing evidence shows that enhancement of sulfate uptake and reduction occurs with the production of PC in plants under heavy metal stress. In this article, the key aspects of our recent understanding of regulatory mechanisms involved in the relation between the sulfate assimilation and phytochelatin synthesis are described.

Bismuth↗

PubMed2006

[Effects of sensitized donor lymphocyte infusion on the chimerism and graft-versus-host disease after nonmyeloablative allogeneic stem cell transplantation].

To explore whether the complete donor chimerism could be achieved and graft-versus-host disease could be alleviated by donor lymphocyte infusion which was sensitized by the skin of the recipient, female C57BL/6 mice (H-2(b), B6) as recipients received total body irradiation (TBI) of 5.5 Gy ((60)Co gamma-ray) on day 0 followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT). The allo-grafts consisted of 2 x 10(7) peripheral hematopoietic stem cells from mobilized male BALB/c (H-2(d)) donor mice with the granulocyte colony-stimulating factor (G-CSF). Day 2 after allo-HSCT, the recipient mice were given 200 mg/kg cyclophosphamide intraperitoneally. Afterwards these recipient mice were infused 2 x 10(6) sensitized or unsensitized-donor lymphocytes at the 28 days after transplantation. The results showed that the mice receiving sensitized-donor lymphocyte infusion did not suffer from GVHD and the phenotypic character of the recipient mice (black color) converted to that of the donor mice (white color), and to become full-donor chimerism. It was found that the ratio of CD4(+)/CD8(+) T lymphocytes of them decreased at the earlier period and increased after half month, but which were also lower than that of the normal value. While various grades of acute GVHD was observed in that of the control group and the mixed-chimeras were maintained, though it increased a little, and the ratio of CD4(+)/CD8(+) T lymphocytes increased at first, then decreased to the normal level half month later. It is concluded that sensitized DLI converted mixed to complete donor chimerism without GVHD, and the rate of CD4(+)/CD8(+) has close relation to the incidence of GVHD.

Animals↗

PubMed2006

[Effect of hematopoietic stem cell transplantation in malignant hematologic disease of lymphatic system].

The study was aimed to investigate the effect of hematopoietic stem cells transplantation (HSCT) in treatment for hematologic malignancies of lymphatic system. Through observing 8 patients with non-Hodgkin's lymphoma (NHL) and 3 patients with lymphoblastic leukemia, who received auto or allo-HSCT after chemotherapy, the hematopoietic reconstitution, complication and survival time were evaluated. The results showed that 11 patients (7 patients after auto-PBSCT, 4 patients after allo-PBSCT) all achieved hematopoietic reconstitution and complete remission (CR). Within three years following-up, 5 patients with NHL were survival, but one case of NHL died at the 2 months after auto-PBSCT, one patient suicided. From 4 cases received allo-PBSCT, one patient with NHL (NK cell) was died at 79 days later, one patient with chronic lymphoblastic leukemia was surviving, another 2 cases of acute lymphoblastic leukemia were dead at 17 months and 54 days respectively after allo-PBSCT. In conclusion HSCT is an effective treatment for hematologic malignancies of lymphatic system, but the replase would occur in some patients received auto-PBSCT. The others by allo-PBSCT might die of severe complication of transplantation.

Adolescent↗

PubMed2005

[Induction of immune tolerance for allogenic recipient mice by non-myeloablative bone marrow transplantation].

This study was aimed to explore the effects and mechanisms of transplantation tolerance induced by "TBI + cyclophosphamide (CTX)" regimen combined with intra-bone marrow injection of allogenic BMCs. On day 0 C57BL/6 (H-2(b), B6) mice received sublethal dose of total body irradiation (TBI) ((60)Co gamma-ray) followed by intrabone marrow-bone marrow transplantation (IBM-BMT) of 3 x 10(7) cells/30 microl BMCs from BALB/c (H-2(d)) mice. The recipient mice were given CTX intraperitoneally 2 days after IBM-BMT. On day 7 skin grafting was performed and the skin survival was observed. The tolerance mechanism was investigated by mixed lymphocyte reaction (MLR), IL-2 reverse test, adoptive transfer assay in vitro. The results showed that the mean survival time (MST) of skin allografts in group treated with TBI + CTX + BMT was significantly longer, compared with that of other groups (P < 0.01). On day 90 after IBM-BMT, the phenotypic character of the recipient mice (black color) began to convert to that of the donor mice (white color). The MLR demonstrated that the immune responses of recipient mice were donor-specific tolerance. Suppressive activity in the spleen cells of tolerant B6 mice was observed in adoptive transfer assay in vitro. IL-2 reversal and the phenotypic conversion showed that the tolerance mechanisms were involved in clonal anergy and the development of chimerism. It is concluded that the nonmyeloablative regimen combined with IBM-BMT can induce a long-term tolerance, and the multiple mechanisms including clonal anergy, suppressor cells and chimerism were involved in transplantation immune tolerance.

Animals↗

PubMed2004

Inhibitory effect of antisense vascular endothelial growth factor 165 eukaryotic expression vector on proliferation of hepatocellular carcinoma cells.

AIM: To construct antisense VEGF(165) eukaryotic expression vector PCDNA(3)-as-VEGF(165) and to study its expression and effect on the proliferation of hepatocarcinoma SMMC-7721 cells. METHODS: VEGF(165) cDNA was inserted into polylinker sites of eukaryotic expression vector PCDNA(3) to construct PCDNA(3)-as-VEGF(165). Then the vector was transferred into human hepatocarcinoma cell strain SMMC-7721 with cation lipofectamine 2000 mediated methods to evaluate the expression of VEGF protein and the inhibitory effect on the proliferation of hepatocarcinoma SMMC-7721 cells. RESULTS: The detection indicated the presence of VEGF cDNA in normally cultured SMMC-7721 cells by PCR. VEGF mRNA expression was notably decreased in SMMC-7721 cells by RT-PCR after PCDNA(3)-as-VEGF(165) transfection. The expression of VEGF protein was dramatically inhibited (142.01+/-7.95 vs 1 625.52+/-64.46 pg/ml(-1), P<0.01) 2 days after transfection, which correlated with the dose of PCDNA(3)-as-VEGF(165)5 gene. VEGF protein was most expressed in PCDNA(3) transferred SMMC-7721 cells but few in PCDNA(3)-as-VEGF(165) transferred cells by immunohistochemical staining. The apoptotic rate of hepatocarcinoma SMMC-7721 cells was significantly promoted (17.98+/-0.86% vs 4.86+/-0.27%, P<0.01) and the survival rate was notably decreased (80.99+/-3.20% vs 93.52+/-3.93%, P<0.05) due to antisense VEGF(165) by flow cytometry (FCM). The transfection of antisense VEGF(165) gene resulted in the inhibitory effect on the proliferation of hepatocarcinoma cells by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and the death of all hepatocarcinoma cells on day 6 after transfection. CONCLUSION: It is confirmed that antisense VEGF(165) can inhibit the expression of VEGF protein, interfere with the proliferation and induce the apoptosis of hepatocarcinoma cells in our study. Antisense VEGF(165) gene therapy may play an important role in the treatment of human hepatocarcinoma.

Carcinoma, Hepatocellular↗

PubMed2004

Abdominal aorta transplantation after programmed cryopreservation.

AIM: To study the morphologic and cellular immunologic changes after homologous transplantation of the abdominal aorta in rats after programmed cryopreservation (-196 degrees). METHODS: Abdominal aorta was harvested from anesthetized Spraque Dawley (SD) rats for cryopreservation (group B) or immediate implantation (group A). The survival rates and apoptotic rates of aortic endothelial cells (ECs) were examined. The patency rates, histology and cellular immunologic changes of the abdominal aorta were examined on days 1, 3, 7, 14, 30, 60 after transplantation respectively. RESULTS: The survival rate of ECs after programmed cryopreservation was 90.1+/-1.79%, about 3.4% lower than that of uncryopreservation (93.5+/-1.96%). The apoptotic rates of ECs was increased after cryopreservation (7.15% vs 4.86%, P<0.05). The patency rate of group B was significantly higher than that of group A (91.6+/-12.9% vs 62.5+/-26.2%, P<0.01). CD4/CD8 ratio, TCR alpha beta and CD11b/CD18 ratio of group B were significantly lower than those of group A (P<0.05). Revivification of the cryopreserved abdominal aorta showed normal adventitia and intact smooth muscle cells. CONCLUSION: Cryopreservation can reduce homologous abdominal aortic antigenecity. Even if without administration of immunosuppressive agents, it is still feasible to implement homologous artery grafting in rats.

Animals↗

PubMed2004

The association of calmodulin with central spindle regulates the initiation of cytokinesis in HeLa cells.

Calmodulin is a major cytoplasmic calcium receptor that performs multiple functions in the cell including cytokinesis. Central spindle appears between separating chromatin masses after metaphase-anaphase transition. The interaction of microtubules from central spindle with cell cortex regulates the cleavage furrow formation. In this paper, we use green fluorescence protein (GFP)-tagged calmodulin as a living cell probe to examine the detailed dynamic redistribution and co-localization of calmodulin with central spindle during cytokinesis and the function of this distribution pattern in a tripolar HeLa cell model. We found that calmodulin is associated with spindle microtubules during mitosis and begins to aggregate with central spindle after anaphase initiation. The absence of either central spindle or central spindle-distributed calmodulin is correlated with the defect in the formation of cleavage furrow, where contractile ring-distributed CaM is also extinct. Further analysis found that both the assembly of central spindle and the formation of cleavage furrow are affected by the W7 treatment. The microtubule density of central spindle was decreased after the treatment. Only less than 10% of the synchronized cells enter cytokinesis when treated with 25 microM W7, and the completion time of furrow regression is also delayed from 10 min to at least 40 min. It is suggested that calmodulin plays a significant role in cytokinesis including furrow formation and regression, The understanding of the interaction between calmodulin and microtubules may give us insight into the mechanism through which calmodulin regulates cytokinesis.

Anaphase↗

PubMed2004

[Immunophenotype analysis in 121 patients with lymphoproliferative diseases by flow cytometry].

BACKGROUND & OBJECTIVE: Multiple parameter immunophenotype analysis by flow cytometry (FCM) could improve the accuracy of diagnosis in lymphoproliferative diseases. This study was to analyze the immunophenotype of 135 samples, including lymph nodes, blood, bone marrow, and cerebrospinal fluid samples, from 121 patients with suspected lymphoid malignancies, to evaluate its role in diagnosis. METHODS: All samples were tested by routine morphological, pathological, and immunohistochemical methods, and analyzed by FCM in suspended single cells, to compare the accuracy of different diagnostic methods. RESULTS: (1) Three of 23 lymph nodes, which failed to be diagnosed by routine methods, were determined by flow cytometric immunophenotype analysis. (2) According to new WHO classification, 96 of 97 blood or bone marrow aspiration samples were diagnosed by flow cytometric immunophenotype analysis, while 88 of 97 samples were diagnosed by routine immunohistochemical method. (3) Multiple parameter immunophenotype analysis in cerebrospinal fluid samples by FCM improved the diagnostic accuracy of leukemia or lymphoma involvement of central nervous system. CONCLUSIONS: Multiple parameter immunophenotype analysis by FCM improves the accuracy of diagnosis in lymphoid malignancies, and can be used in diagnosis, differentiated diagnosis, and detection of minimal residue in lymphoproliferative diseases.

Adolescent↗

PubMed2003

Ischemic preconditioning decreases C-X-C chemokine expression and neutrophil accumulation early after liver transplantation in rats.

AIM: Polymorphonuclear neutrophil (PMN) plays a major role in liver ischemia/reperfusion injury. Protective effect of ischemic preconditioning (IP) has been confirmed in liver ischemia/reperfusion injury. The purpose of this study was to investigate the effect of IP on C-X-C chemokine expression and PMNs recruitment early after liver transplantation. METHODS: Male Sprague-Dawley rats were used as donors and recipients of orthotopic liver transplantation (OLT). The donor liver was stored 24 hours in University of Wisconsin (UW) solution at 4 degrees pre-implantation. IP was done by clamp of the portal vein and hepatic artery of the donor liver for 10 minutes followed by reperfusion for 10 minutes before harvesting. The neutrophilic infiltration in liver was quantified using a myeloperoxidase (MPO) assay. Intragraft expression of macrophage inflammatory protein-2 (MIP-2) mRNA was investigated with in situ hybridization. The serum levels of MIP-2 and tumor necrosis factor (TNF)-alpha were also monitored. RESULTS: After liver transplantation without IP, the hepatic MPO increased significantly compared with sham operated group. In IP group, PMN in liver indicated by MPO was reduced significantly. In situ hybridization showed no MIP-2 mRNA in sham group but dramatic expression in hepatocytes in non-IP group. In IP group, MIP-2 mRNA was significantly down-regulated. Similarly, serum MIP-2 and TNF-alpha levels were significantly elevated in non-IP group and both were reduced in IP group. CONCLUSION: IP might protect graft liver from preservation-reperfusion injury after OLT through down-regulating C-X-C chemokine expression of hepatocytes, and alleviating PMNs recruitment after reperfusion.

Animals↗