Search PubMed⌕ Search

Biomedical subjects

Bing Xu

Publications and source records attributed to Bing Xu.

At least 55 records · Page 3Linked to original sources
PubMed2004

Molecular recognition remolds the self-assembly of hydrogelators and increases the elasticity of the hydrogel by 10(6)-fold.

Addition of vancomycin (1, the receptor) to the supramolecular hydrogel of self-assembled pyrene-d-Ala-d-Ala (2, the ligand) increases the storage modulus of the hydrogel of 2 by about 106-fold. Rheology, microscopy, and spectroscopy investigations suggest that the two-dimensional polymers, formed by the ligand-receptor interaction between 1 and 2, and the self-dimerization of 1, are mainly responsible for the observed dramatic increase in elasticity.

Biomimetic Materials↗
PubMed2004

Dopamine as a robust anchor to immobilize functional molecules on the iron oxide shell of magnetic nanoparticles.

We report on the use of dopamine (DA) as a robust molecular anchor to link functional molecules to the iron oxide shell of magnetic nanoparticles. Using nitrilotriacetic acid (NTA) as the functional molecule, we created a system with an M/Fe2O3-DA-NTA (M = Co or SmCo5.2) nanostructure, which possesses high stability and specificity for separating histidine-tagged proteins. The well-established biocompatibility of iron oxide and the robust covalent bonds between DA and Fe2O3 render this strategy attractive for constructing biofunctional magnetic nanoparticles containing iron oxide.

Dopamine↗
PubMed2004

Facile one-pot synthesis of bifunctional heterodimers of nanoparticles: a conjugate of quantum dot and magnetic nanoparticles.

Sequential addition of sulfur and Cd(acac)2 into the colloid solution of FePt nanoparticles ( approximately 2.5 nm) under a reductive environment generates heterodimers of CdS and FePt with sizes of approximately 7 nm. The heterodimers exhibit both superparamagnetism and fluorescence, indicating that the discrete properties of the individual parts of the dimers are preserved. This simple methodology may lead to the production of large quantities of various heterostructures with tailored properties on the nanoscale.

Journal Article↗
PubMed2004

Nitrilotriacetic acid-modified magnetic nanoparticles as a general agent to bind histidine-tagged proteins.

Using Nalpha,Nalpha-bis(carboxymethyl)lysine to react with FePt magnetic nanoparticles, we synthesized the FePt-NTA conjugate, which immobilizes Ni2+ ions and selectively binds to histidine-tagged proteins at concentration as low as 0.5 pM. This simple system serves as a useful alternative to existing protocols for protein separation and also acts as a versatile agent for transporting and anchoring proteins.

Alloys↗
PubMed2004

[Detection of mutation and protein expression of PTEN gene in endometrial carcinoma].

BACKGROUND & OBJECTIVE: PTEN (phosphatase and tensin homolog deleted on chromosome ten), a novel tumor suppressor gene identified recently, is called the house-keeping gene of endometrium. However, little is known about its precise role in genesis and development of endometrial carcinoma. In the present study, the mutation and protein expression of PTEN gene were investigated to seek the clinical significance. METHODS: Fifty-two endometrial carcinoma samples and 10 normal endometrial tissues were collected. The mutations of exon 5 and exon 8 of PTEN gene were examined by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing analysis. The expression of PTEN protein was evaluated by immunohistochemistry method. The results associated with clinical pathological features were analyzed. RESULTS: In endometrial carcinomas, the rates of mutation and protein expression deletion of PTEN were 25% and 60%, respectively, which were significantly higher than that of normal endometrium (0%) (P< 0.05). The samples at pathological G(1) and G(2) and depth of myometrial invasion less than 1/2 demonstrated higher mutation rate than that of G3 and depth of myometrial invasion more than or equal to 1/2 (P< 0.05). In contrast, the rate of protein expression deletion of G(1) and G(2) was significantly lower than that of G3 (P< 0.05). Both mutation and protein expression deletion showed statistical differences between endometrioid adenocarcinoma and other types of endometrial carcinomas (P< 0.05), but no significant difference was found at different surgical-pathological stage (P >0.05). CONCLUSION: Mutation and positive protein expression of PTEN occurred more frequently in the endometrial carcinoma cases with low pathological stages.

Adult↗
PubMed2004

[Clinical efficacy and side effects of STI571 in treatment of patients with chronic myeloid leukemia].

BACKGROUND & OBJECTIVE: The aberrant regulation of the protein tyrosine kinase (PTK) activity of P210(BCR-ABL), which is the protein product of Bcr-Abl fusion gene leads to the pathogenesis of chronic myeloid leukemia (CML). Though STI571 can inhibit specifically the PTK activity of P210(Bcr-Abl) and greatly improve the clinic curative effect on CML in chronic phase, its effect on CML in accelerated phase and blast crisis is not clear. In this article, we attempted to analyze the clinic efficacy and side effect of STI571 treatment on CML patients in different phase. In addition, we analyzed the potential mechanism of STI571 resistance in accelerated/blast crisis CML with genetic methods. METHODS: A total of 22 cases of CML, 14 cases male and 8 female, 6 cases in chronic phase and 16 cases in accelerated/blast crisis phase, were treated with STI571. According to the efficacy standard, the hematological and cytogenetic response of 22 cases CML were analyzed, by determining the positive rate of Ph chromosome in bone marrow from the patients treated with STI571 for 3 months. Furthermore, the karyotype evolution of those patients showing STI571 resistance was analyzed. At the same time, the side effects and adverse events of STI571 treatment were evaluated. RESULTS: 6/6(100%) cases of CML patients in chronic phase acquired hematological CR and cytogenetic response. 4/16(25%) cases in accelerated phase or blast crisis acquired hematological CR and 8/16(50%) cases acquired cytogenetic response. 3 CML patients in blast crisis showed secondary STI571 resistance. The karyotype analysis shows 2 with 2 Ph chromosome and other additional abnormality. I/II grade non-hematological toxicity was observed in all the patients, including edema (77.3%), side effects of digestive system (36.4%) and myalgia (22.7%) et al. Severe hematological toxicities includes:(1)III/IV grade neutropenia (9 cases):1/6 cases of CML patients in chronic phase, 8/16 cases in accelerated phase or blast crisis; (2)III/IV grade thrombocytopenia (6 cases): 6/16 cases in accelerated phase or blast crisis. The percentage of III/IV grade neutropenia/thrombocytopenia in chronic phase and accelerated/blast crisis phase was compared and no significant statistical difference was observed. CONCLUSIONS: Hematological and cytogenetic responses of different degrees can be acquired in CML-CP and CML-AP/BC patients treated with STI571 and showing statistic difference. STI571 improves the clinic curative effect greatly on CML in chronic phase. CML patients in blast crisis have secondary STI571 resistance with novel 2 Ph chromosome and other additional abnormality, it furnishes the evidence of the gene changes. The slightness of non-hematological toxicity of STI571 in the treatment of chronic myeloid leukemia suggests this drug is relatively safe. Severe hematological toxicities, such as III/IV neutropenia and thrombocytopenia, are more common in accelerated/blast crisis than in chronic phase.

Adolescent↗
PubMed2004

[Hematopoietic stem cell transplantation for patients with chronic myelogenous leukemia].

BACKGROUND & OBJECTIVE: Chronic myelogenous leukemia (CML) is a malignant hematological disease.CML patients are commonly treated with hematopoietic stem cells transplantation (HSCT). This study was designed to evaluate the effect of HSCT on the patients with CML. METHODS: Forty-four patients with CML were treated by HSCT, including 8 cases treated with purging autologous transplantation, 30 cases with related donor allogeneic HSCT (allo-HSCT), and 6 cases with unrelated donor allo-HSCT. The conditioning regimen was TBI (total-body irradiation)+CY (CTX) protocol in 31 patients and modified BuCY (hydroxyurea, busulfan, Ara-C, CTX) protocal in 12 patients, and MACC (Melphalan, Ara-C, CTX and CCNU) protocol in one patient. CsA (cyclosporine) and MTX were used in the patients with related donor allo-HSCT, and CsA and MTX added to mycophenolate mofetil (MMF) and antithymocyte globulin (ATG) were used in the patients with unrelated donor all-HSCT for graft versus host disease (GVHD) prophylaxis. Otherwise, CsA was only used in the patients with accelerated phase(AP) and blast crisis(BC) for GVHD prophylaxis. Kaplan-Meier survival analysis model was used to estimate the overall survival (OS) and the disease-free survival (DSF) at 5 years after transplantation. RESULTS: Eight patients with autologous transplantation, except one case died of transplantation-related-complication, obtained part or complete cytogenetic remission within 3 months after transplantation. One patient, who was BC and obtained complete remission (CR) in hematology before transplantation,obtained complete molecular remission for 81 months after autologous transplantation. All patients obtained CR, except one patient died of hepatic veno-occlusive disease (VOD) and one case did not obtained CR, in 36 patients with allo-HSCT after transplantation. The incidence of infection and VOD during transplantation were 38.6% and 9.1%, respectively. The incidences of hemorrhagic cystitis (HC) and cytomegalovirus (CMV) pneumonia after transplantation were 15.9% and 11.4%, respectively. VOD, HC, and CMV pneumonia did not occur in the patients with autologous transplantation. The incidence of acute GVHD in the patients with related and unrelated donor transplantation were 40.0% and 33.3%, respectively. The incidence of chronic GVHD was 43.4% in the patients with related donor transplantation. The rates of transplant-related mortality (TRM) in the patients with autologous and allogeneic transplantation were 12.5% and 16.7%, respectively. The rates of relapse in patients with autologous and related donor transplantation were 37.5% and 13.3%, respectively. The DFSs at 5 years in patients with autologous and related donor transplantation after transplantation were 18.7% and 53.7%, respectively. The DFS at 5 years in patients with CP (chronic phase) or AP and BC before transplantation were 66.4% and 26.7%, respectively. CONCLUSION: all-HSCT shows higher clinical cure rate to CML patients with CP. CsA+MTX+MMF+ATG protocol is more effective for acute GVHD prophylaxis and can decrease the incidence and severity of acute GVHD in patients with unrelated donor transplantation. Autologous transplantation with bone marrow purged can prolong the survival time and a few patients may be cured with autologous transplantation in CML.

Adolescent↗
PubMed2004

[In vitro cleavage activity of the ribozymes constructed specifically for the second exons of pro alpha I and III collagen genes].

OBJECTIVE: To study the in vitro cleavage activity and the reaction conditions of the hammerhead ribozymes for the second exons of pro alpha 1I and III collagen genes, and observe the effect of the two ribozymes on collagen synthesis by the fibroblasts in scar tissue. METHODS: The fragments of the second exons of pro alpha 1I and III collagen genes were cloned into the plasmids pT-I and pT-III and labeled with (32)P during transcription to obtain the target RNA. The transcription products of the plasmids pT-gI and pT-gIII containing specific ribozymes were incubated with the label target RNAs, respectively, under various conditions, and the results observed by electrophoresis autoradiography. The constructed ribozymes were transduced into cultured fibroblasts via liposomes for investigation of their effects on mRNA synthesis of type I and III collagen protein by image analysis. RESULTS: The two ribozymes (rgI and rg III) could efficiently cleave their target RNAs at both 37 degrees Celsius and 42 degrees Celsius, in the presence of Mg(2+) within a relatively wide concentration range form 10 to 20 mmol/L. When the temperature was lowered from 65 degrees Celsius to 37 degrees Celsius and maintained at 37 degrees Celsius, the cleavage activity of the ribozymes reached the maximum. The expression of mRNA of I and III collagen decreased accompanied by reduced collagen synthesis. CONCLUSION: Hammerhead ribozymes for the fragments of the second exons of pro alpha 1I and III collagen genes can cleave its target RNAs in vitro and effectively inhibit the collagen synthesis by the scar-derived fibroblasts.

Cicatrix↗
PubMed2004

[Eosinophilic granuloma of the jaw: an analysis of 21 cases].

PURPOSE: To study the clinical features and treatment of eosinophilic granuloma of the jaw (EGJ) in 21 cases. METHODS: 21 patients with EGJ treated from 1983 to 2002 were reviewed, including the sexes, ages, extent of lesions, clinical features and treatment methods. RESULTS: The male to female rate was 13:8. 76% of the cases were among 2-10 years. The median age was 8 years, 18 lesions were in the mandible, 1 was in the maxilla and 2 involved the mandible and maxilla. CONCLUSIONS: EGJ was rarely seen clinically, lack of specificity. Pathology can confirm the diagnosis. Surgery is still the major treatment modality. Combination of radiotherapy or chemotherapy maybe valuable. The prognosis of the patients was generally good.

Age Factors↗
PubMed2004

[Establishment of a real time quantitative-PCR assay for detection of TCR VgammaI-Jgamma gene rearrangement in acute lymphoblastic leukemia patients].

OBJECTIVE: To improve the techniques for minimal residual disease (MRD) detection in acute lymphoblastic leukemia (ALL). METHODS: A real time quantitative PCR method was established for quantifying the clonal TCRVgammaI-Jgamma gene rearrangement in 36 ALL patients. RESULTS: The sensitivity of the established real time quantitative PCR was at 10(-4) level. The amount of TCRVgammaI-Jgamma gene rearrangement in newly diagnosed group, complete remission (CR) group and post hematopoietic stem cell transplantation (HSCT) group was (7.38 +/- 6.65) x 10(-2), (1.02 +/- 1.08) x 10(-2) and (3.89 +/- 5.65) x 10(-3) level, respectively. and the amount in newly diagnosed group was higher than that in CR group and HSCT group (P = 0.001). The MRD level of ALL patients in CR group was higher than that in HSCT group (P = 0.022). MRD can be detected in 6 ALL patients after HSCT, 2 of them with low MRD level (< 1 x 10(-3)) survived long disease-free survival, the other 4 with high MRD level relapsed within one year. CONCLUSION: The established real time quantitative PCR assay is simple, rapid, sensitive and specific. Use of this assay to evaluate MRD in the remission ALL cases is helpful for prognosis prediction.

Adolescent↗
PubMed2004

[Low-dose granulocyte colony-stimulating factor combined with granulocyte-macrophage colony-stimulating factor for mobilizing peripheral CD34+ hematopoietic progenitor cells].

OBJECTIVE: To study the efficacy of combined use of low-dose granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in mobilizing hematopoietic stem/progenitor cells. METHODS: Twenty adult patients with malignant hematologic diseases were paired using statistical methods, and the 10 pairs were divided into 2 equal groups. For non-Hodgkin lymphoma, the treatment regimen adopted intravenous infusion of cytoxan (2 g/d for 1 or 2 d) and VP16 (0.2 g/d for 1 to 3 d), while for acute non-lymphocytic leukemia, Ara-C (2 g/d for 1 to 3 d) and VP16 (0.2 g/d for 1 to 3 d) were used. When the while blood cell count (WBC) was below 1.0 x10(9)/L, G-CSF and GM-CSF were administered subcutaneously at the same dose of 2.5 microg/d.kg in the 10 patients in the experimental group, while the patients in the control group received only 5 microg/d.kg G-CSF, both for 5 to 6 d. After WBC>5.0 x 10(9)/L, the peripheral blood mononuclear cells (PBMNC) were separated by CS-3000 pluse separator and CD34+ cells were determined by flow cytometry. RESULTS: The purity of the isolated PBMNC was 95%-99%. In the experimental group, the mean number of CD34+ cells acquired was 9.4 x 10(6)/kg ranging from 8.4 x 10(6) to 10.2 x 10(6)/kg, and granulocyte-macrophage colony-forming unit (CFU-GM) was 42.4 x 10(4)/kg on average ranging from 21.9 x 10(4) to 72.8 x 10(4)/kg, as compared with 4.8 x 10(6)/kg [(4.1-8.3) x10(6)/kg] for CD34+ cells and 28.1 x 10(4)/kg [(7.1-60.2) x 10(4)/kg] for CFU-GM in the control group (P<0.05). No obvious difference was observed between the two groups in terms of the adverse effects of the treatment (P>0.05). CONCLUSION: Combined use of G-CSF and GM-CSF can be more effective than the exclusive use of GM-CSF for mobilizing CD34+ cells.

Adult↗
PubMed2004

[Detection of FLT3 gene and FLT3/ITD gene mutation in chronic myeloid leukemia and its significance].

BACKGROUND & OBJECTIVE: Fms-like tyrosine kinase 3 (FLT3)gene abnormal expression could be detected in most of acute myeloid leukemia (AML)patients, and 20%-30% of them have FLT3/ITD gene mutation which indicate poor prognosis. This study was to detect FLT3 gene expression, and FLT3/ITD gene mutation in chronic myeloid leukemia (CML)patients, and analyze their relationships with prognosis. METHODS: Polymerase chain reaction (PCR)was used to detect FLT3 gene expression, and FLT3/ITD gene mutation in 53 CML patients of chronic phase,and 34 CML patients of accelerated phase or blast crisis. RESULTS: FLT3 gene was detected in 5.7%(3/53)CML patients of chronic phase, and in 55.9% (19/34)CML patients of accelerated phase or blast crisis,the difference of FLT3 gene positive rate between these 2 groups was significant (P< 0.001). Only 2 of 87 CML patients (2.3%)were found with FLT3/ITD mutation. CONCLUSIONS: FTL3 gene expresses mainly in CML patients of accelerated phase or blast crisis. FTL3/ITD gene mutation was seldom involved in CML patients. The CML patients with FLT3 gene expression and FTL3/ITD gene mutation may have poor prognosis.

Adult↗
PubMed2004

[Therapeutic efficacy of hematopoietic stem cell transplantation in patients with chronic myelogenous leukemia].

OBJECTIVE: To evaluate the clineffects of autologous and allogeneic hematopoietic stem cell transplantation (HSCT) for chronic myelogenous leukemia (CML). METHODS: Fifty-seven patients with CML were treated by HSCT, including 8 patients treated with autologous transplantation in vivo and vitro purging minimal residual disease (MRD), 39 with related donor allogeneic HSCT (allo-HSCT), and 10 with unrelated donor allo-HSCT. For the conditioning regimen, total-body irradiation with cyclophosphamide (CTX) was given in 32 patients, modified BuCY protocol (hydroxyurea, busulfan, Ara-C, CTX) in 24 patients, and MACC protocol (melphalan, Ara-C, CTX and lomustine) in one patient. Cyclosporine (CsA) and methotrexate (MTX) were used in patients with related donor allo-HSCT, and the combination of CsA, MTX , mycophenolate mofetil (MMF), and antithymocyte globulin (ATG) in unrelated donor all-HSCT to prevent graft versus host disease (GVHD). Kaplan-Meier survival analysis model was used to estimate the overall survival and the disease-free survival (DFS) at 5 years after transplantation. RESULTS: In 8 patients with autologous transplantation, 7 obtained partial or complete cytogenetic remission (CR) within 3 months after transplantation and one died of transplantation-related complication. In 49 patients with allo-HSCT transplantation, all patients obtained CR except for two patients, one of whom failed to obtain CR and the other died of hepatic veno-occlusive disease. The incidence of infection and veno-occlusive disease during transplantation was 33.3% and 7.0%, respectively. The incidence of hemorrhagic cystitis and cytomegalovirus interstitial pneumonia after transplantation was 22.8% and 8.8%, respectively. Veno-occlusive disease, hemorrhagic cystitis or cytomegalovirus interstitial pneumonia did not occur in patients with autologous transplantation. The incidence of acute GVHD was 41.0% and 48.6%, and that of chronic GVHD 40.0% and 42.9% in patients with related and unrelated transplantation, respectively. The rate of relapse was 57.1% and 12.8%, with DFS at 5 years of 25.0% and 61.7%, respectively, in patients with autologous and related donor transplantation. The DFS at 5 years was 70.7% and 34.1%, respectively, in patients with chronic/accelerated phases and blast crisis be fore trans plantation. CONCLUSION: allo-HSCT can produce a higher clinical cure rate in CML patients in chronic phase CsA+MTX+MMF+ ATG protocol is more effective for prevention and alleviation of acute GVHD in patients with unrelated donor transplantation. Autologous transplantation with bone marrow purging helps prolong the patients' survival and even obtain clinical cure of CML.

Adolescent↗
PubMed2003

Using biofunctional magnetic nanoparticles to capture vancomycin-resistant enterococci and other gram-positive bacteria at ultralow concentration.

Covalently linked to vancomycin (Van), chemically stable and highly magnetic anisotropic FePt magnetic nanoparticles (3-4 nm) become water-soluble and capture vancomycin-resistant enterococci (VRE) and other Gram-positive bacteria at concentrations approximately 10(1) cfu/mL via polyvalent ligand-receptor interactions. When a pyramidal end of a magnet "focuses" the nanoparticles into approximately 1 mm(2) area, the bacteria can be observed by an optical microscope and further identified by electron micrograph (EM). Compared to the conventional use of magnetic particles (with the sizes of 1-5 microm) in biological separation or drug delivery, magnetic nanoparticles, combined with specific receptor-ligand interactions, promise a sensitive and rapid protocol to detect pathogens.

Alloys↗