Biomedical subjects

Rui Zhang

Publications and source records attributed to Rui Zhang.

At least 109 records · Page 6Linked to original sources

PubMed2005

[Study on apoptosis of human cervical carcinoma HeLa cells with RNA interference targeting hTERT].

AIM: To study the induction of tumor cell apoptosis by RNA interference-mediated inhibition of the expression of telomerase in cancer cells. METHODS: HeLa cells were transfected with the successfully established siRNA(small interfering RNA) expression vectors targeting hTERT (human telomerase reverse transcriptase). By electronic microscopy, Western blot and FCM (flow cytometry), the apoptosis of HeLa cells was tested. RESULTS: The established siRNA expression vectors could induce apoptosis of HeLa cells. CONCLUSION: Transfection of siRNA expression vectors targeting hTERT can induce apoptosis of HeLa cells.

Animals↗

PubMed2005

[Risk factors affecting the long-term outcome of IgA nephropathy].

OBJECTIVE: To study the risk factors predicting long-term renal survival of IgA nephropathy in Chinese. METHODS: Clinical and pathological data of 317 patients (124 males and 193 females) with IgA nephropathy confirmed by renal biopsy in our center from January 1987 to February 2003 were reviewed retrospectively and were correlated with outcomes. A semiquantitative scoring system was used to evaluate individual pathological lesion of the kidney. Patients were followed for at least 6 months and doubling of serum creatinine level was defined as endpoint of follow-up. Renal survival was calculated by Kaplan-Meier survival analysis and risk factors of progression were analyzed by using univariate and multi-variate Cox regression models. RESULTS: The average age at renal biopsy was (30.1 +/- 10.9) years and the average duration from onset of disease to the time of biopsy was (20.1 +/- 33.7) months. Thirty-two percent of the patients had 24 h-urinary protein excretion greater than 1.0 g at the time of biopsy. Thirty-two percent of the patients had hypertension and 20.8% had renal insufficiency. Thirty-five percent of the patients were of Lee's grade IV or above and 20.5% presented with small proportion of crescent formation (usually less than 20%). Patients were followed for an average duration of (43.5 +/- 32.2) months with 39 patients (12.3%) reaching the endpoint. The 1-, 3-, 5- and 10-year renal survival was 99.5%, 93.1%, 84.5% and 60.1% respectively. Univariate Cox regression analysis revealed that longer duration of the disease before biopsy, serum creatinine > 115 micromol/L, proteinuria > 1.0 g/d, hypertension, Lee's grading of IV-V, moderate-severe glomerulosclerosis, crescent formation, moderate-severe interstitial fibrosis and renal arteriolar lesion were risk factors of disease progression, with an odds ratio of 1.007, 9.61, 7.31, 3.97, 5.41, 5.78, 4.65, 14.05 and 2.28 respectively (P < 0.001). Episodic macro-hematuria had an odds ratio of 0.194 (P < 0.05). Age, sex, serum cholesterol and triglyceride level had no significant impact on prognosis. Proteinuria, elevated serum creatinine, glomerulosclerosis, crescent formation and interstitial fibrosis were confirmed to be independent risk factors by multi-variate Cox regression model while the remaining variables were not statistically significant. Patients with both renal insufficiency and proteinuria greater that 1.0 g/24 h at the time of biopsy had a very poor 5-year renal survival (41.8%). CONCLUSIONS: Proteinuria, renal insufficiency, glomerulosclerosis, crescent formation and interstitial fibrosis were independent risk factors predicting the renal survival. IgA nephropathy presented with proteinuria, hypertension and crescent formation may need intervention.

Adolescent↗

PubMed2005

[Tryptase relation to VEGF in acute leukemia].

In order to investigate the role of tryptase in angiogenesis of acute leukemia (AL), the expressions of tryptase and vascular endothelial growth factor (VEGF) in leukemic cells from 61 patients with AL were examined by using immunocytochemical method, and the correlation between tryptase and VEGF was analyzed. The results showed that tryptase positive expression was found in 15 out of 51 patients with acute myeloid leukemia (AML) (M(1) 1/3, M(2) 7/15, M(3) 5/20, M(5) 2/8). Tryptase positive expression was 29.4% in AML. However, none of 10 patients with acute lymphocytic leukemia (ALL) showed tryptase expression. There were no correlations between the amounts of cells with tryptase expression and patient age, WBC count, numbers of blood or marrow myeloblasts and neutrophil POX. VEGF expression was revealed in 41 patients with AML (80.4%) and only 3 with ALL (30%). Significant correlation has been found between the expression of tryptase and that of VEGF in AML-M(2) (r = 0.65, P < 0.05). It is concluded that tryptase appears to be a myeloid-specific marker in AML and may be involved in the angiogenesis of AML-M(2).

Biomarkers, Tumor↗

PubMed2005

[Luminescence properties of Gd2O3:Eu3+ sol-gel thin films].

In this paper, the sol-gel method with Re2O3 (Re=Gd, Eu) as parent compounds was introduced to produce Gd2O3:Eu3+ thin films. From the luminescence intensities of the films doped with different Eu3+ concentration and annealed at different temperatures, it was found that the optimal dopant concentration and annealing procedure was 10% and 800 degrees C for 2 hours, respectively. By comparing the excitation spectra of the Gd2O3:Eu3+ film and powder, the authors found that the film has higher efficiency for energy transfer from host to dopant, which means that the film would be more suitable than the powder as a radio-luminescence material. In addition, it was first discovered that the luminescence of the film nearly disappeared after 2 hours annealing at 1000 degrees C. The phenomenon was explained with the results of SEM and XRD experiments.

Europium↗

PubMed2005

[Co-expression of crystal protein gene cry26Aa and cry28Aa has an ability to form parasporal crystal inside exosporium in Bacillus thuringiensis subsp. finitimus].

Parasporal crystal in Bacillus thuringiensis subsp. finitimus T02 forms within the exosporium and remains attached to the spore after mother cell lysis, which leads to spore-crystal connection. According to the crystal protein gene sequence in B. thuringiensis subsp. finitimus, cry26 and cry28 were cloned from strain T02 by PCR amplification and transformed into the crystal negative Bacillus thuringiensis strain BMB171 by shuttle vectors, alone or in combination together. Crystal can be observed inside of exosporium when co-expression of these two genes. But crystal mainly formed outside of exosporium when they expressed alone. This suggests interaction between of the two crystal proteins may be involved in enclosure.

Bacillus thuringiensis↗

PubMed2004

Study of mixtures of n-dodecyl-beta-D-maltoside with anionic, cationic, and nonionic surfactant in aqueous solutions using surface tension and fluorescence techniques.

Surfactants of practical interest are invariably mixtures of different types. In this study, mixtures of sugar-based n-dodecyl-beta-D-maltoside with cationic dodecyltrimethylammonium bromide, anionic sodium dodecylsulfate, and nonionic pentaethyleneglycol monododecyl ether in solution, with and without supporting electrolyte, have been studied using surface tension and fluorescence spectroscopic techniques. Interaction parameters and mole fraction of components in mixed micelles were calculated using regular solution theory. The magnitude of interactions between n-dodecyl-beta-D-maltoside and other surfactants followed the order anionic/nonionic > cationic/nonionic > nonionic/nonionic mixtures. Since all surfactants have the same hydrophobic groups, strengths of interactions are attributed to the structures of hydrophilic headgroups. Electrolyte reduced synergism between n-dodecyl-beta-D-maltoside and ionic surfactant due to charge neutralization. Industrial sugar-based surfactant, dodecyl polyglucoside, yielded results similar to that with dodecyl maltoside, implying that tested commercial alkyl polyglucosides are similar to the pure laboratory samples in synergistic interactions with other surfactants. Fluorescence study not only supported the cmc results using tensiometry, but showed that interfaces of all the above mixed micelle/solution interfaces are mildly hydrophobic. Based on these results, an attempt is made to discover the nature of interactions to be a combination of intermolecular potential energies and free energy due to packing of surfactant molecules in micelles.

Anions↗

PubMed2004

Enhancement of the solubilization capacity of water in Triton X-100/cyclohexane/water system by compressed gases.

The effect of compressed CO2 and ethylene on the properties of Triton X-100/cyclohexane/water systems was studied at different temperatures and pressures. Surprisingly, it was discovered that the compressed gases had the functions of co-surfactants. At suitable pressures, the water-to-surfactant molar ratio (W0) was enhanced significantly by the dissolution of the gas in the solution. The microenvironment in the reverse micelles was investigated by UV-visible spectroscopy by using methyl orange (MO) as a probe. The influence of n-hexane, Na2CO3, NaHCO3, H2C2O4, and CaCl2 at various concentrations on the solubilization of water in the absence of compressed gases was also investigated in order to obtain some information about the mechanism of the interesting phenomenon. This new route to stabilize reverse micelles may have potential applications to other similar systems. Moreover, the results of this work provide some useful information to get insight into the mechanism of co-surfactants, because a conventional co-surfactant usually contains both polar group and hydrocarbon chain, and it is very difficult to clarify the functions these two groups, while the gases used in this work are small nonpolar molecules, which solely have the function of the hydrocarbon chain in a co-surfactant.

Journal Article↗

PubMed2004

Abnormal micellar growth in sugar-based and ethoxylated nonionic surfactants and their mixtures in dilute regimes using analytical ultracentrifugation.

To develop structure-property relationships for surfactants that control their adsorption, solubilization, and micellization behavior in mixed systems and to develop predictive models based on such relationships, it is necessary to acquire quantitative information on various species present in these complex systems. The analytical ultracentrifugation technique is selected for the first time to characterize the species present in mixed micellar solutions due to its powerful ability to separate particles on the basis of their size and shape. Two nonionic surfactants, n-dodecyl-beta-D-maltoside (DM) and nonyl phenol ethoxylated decyl ether (NP-10), and their 1:1 molar ratio mixture were investigated in this study. Micelles of the nonionic surfactants and their mixture are asymmetrical in shape at the critical micelle concentration (cmc). Interestingly, unlike ionic surfactants, the micellar growths of the nonionic surfactants were found to occur at concentrations immediately above the cmc. The results from both sedimentation velocity and sedimentation equilibrium experiments suggest coexistence of two types of micelles in nonyl phenol ethoxylated decyl ether solutions and in its mixture with n-dodecyl-beta-D-maltoside, while only one micellar species is present in n-dodecyl-beta-D-maltoside solutions. Type 1 micelles were primary micelles at the cmc, while type 2 micelles were elongated micelles. The differences in the micellar shapes of n-dodecyl-beta-D-maltoside and nonyl phenol ethoxylated decyl ether are attributed to packing parameters detected by their molecular structures.

Journal Article↗

PubMed2004

Effect of structure of PEO-PPO-PEO copolymers on reverse micelle formation induced by compressed CO2.

The micellization of PEO-PPO-PEO block copolymers in p-xylene has been studied in the presence of CO2. With the application of CO2, some copolymers with suitable molecular weights and EO ratios can form reverse micelles with critical micellization pressure up to 5.8 MPa. For the copolymers with the same length of PO block, higher EO ratios facilitate reverse micelle formation. For the copolymers with the same composition, higher molecular weight is favorable to form reverse micelles. With the suitable composition and molecular weight, the critical micelle pressure (CMP) of copolymers decreases with the increase in the lengths of PEO and PPO blocks due to the hydrophilic and folding effects, respectively. Both the EO ratios and the molecular weights are important for the formation of reverse micelle. The reverse micelle solution can solubilize water with W0 (molar ratio of water to EO segment) up to 3.3.

Journal Article↗

PubMed2004

A caspase-6 and anti-human epidermal growth factor receptor-2 (HER2) antibody chimeric molecule suppresses the growth of HER2-overexpressing tumors.

Clinical studies have suggested that human epidermal growth factor receptor-2 (HER2) provide a useful target for antitumor therapy. We previously described the generation of a chimeric HER2-targeted immunocasp-3 protein. In this study, we extend the repertoire of chimeric proapoptotic proteins with immunocasp-6, a construct that comprises a HER2-specific single-chain Ab, a single-chain Pseudomonas exotoxin A, and an active caspase-6, which can directly cleave lamin A leading to nucleus damage and inducing programmed cell death. We demonstrate that the secreted immunocasp-6 molecule selectively recognizes and induces apoptosis in HER2-overexpressing tumor cells in vitro, but not in cells with undetectable HER2. The immunocasp-6 gene was next transferred into BALB/c athymic mice bearing human breast SK-BR-3 tumors by i.m. injection of liposome-encapsulated vectors, by intratumor injection of adenoviral vectors, or by i.v. injection of PBMC modified by retroviral infection. Regardless of the method used, expression of immunocasp-6 suppressed tumor growth and prolonged animal survival significantly. Our data show that the chimeric immunocasp-6 molecule can recognize HER2-positive tumor cells, promptly attack their nucleus, and induce their apoptotic death, suggesting the potential of this strategy for the treatment of human cancers that overexpress HER2.

ADP Ribose Transferases↗

PubMed2004

Step-height measurement by means of a dual-frequency interferometric confocal microscope.

A novel instrument, the dual-frequency interferometric confocal microscope (DICM), which facilitates the measurement of step features, is investigated. It combines the advantages of the high resolution (subnanometer) of heterodyne interferometry and the relatively large measurement range (approximately 5 microm) of confocal microscopy. The axial response curves of the confocal microscopy system are compared in experiments in which microscopic objects with various numerical apertures and magnifications are used. The results prove that the variation in light intensity is enough to permit discrimination of different orders of interference fringes. The DICM has been successfully utilized to measure the step height of a standard mask, and the experimental results agree well with those measured by scanning probe microscopes. The results also show that the system has good repeatability, with a maximum deviation of 5 nm.

Journal Article↗

PubMed2004

CD40 ligand dysregulation in HIV infection: HIV glycoprotein 120 inhibits signaling cascades upstream of CD40 ligand transcription.

IL-12 production and up-regulation of CD40 ligand (CD40L) expression are impaired in the PBMC of HIV-infected donors, and exogenous CD40L rescues IL-12 production by such cells. In this study, we implicate dysregulation of CD40L expression in the IL-12 defect associated with HIV by demonstrating that induction of CD40L expression by anti-CD3/CD28 stimulation was directly correlated with the IL-12 productive capacity of PBMC. Further, we demonstrate marked decreases in the induction of CD40L protein and mRNA following anti-CD3/CD28 stimulation in HIV-infected donors compared with uninfected donors, with a tight association between these two levels. Inhibition of CD40L up-regulation was selective, as induction of CD69 or OX40 was not as severely affected. Increased instability of CD40L mRNA did not constitute a major mechanism in CD40L dysregulation, thus suggesting a potential defect in the signaling cascades upstream of transcription. The mechanisms by which HIV infection affects the induction of CD40L expression appear to involve HIV gp120-mediated engagement of CD4. Indeed, anti-CD4 mAb or inactivated HIV virions that harbor a conformationally intact gp120 significantly inhibited CD40L up-regulation at both the protein and mRNA levels. This inhibition was due to the native, virion-associated gp120, as coculture with soluble CD4 or heat treatment of inactivated HIV abolished their effect. These in vitro models mirror the CD40L defect seen in cells from HIV-infected donors and thus provide a suitable model to investigate HIV-induced CD40L dysregulation. Clear elucidation of mechanism(s) may well lead to the development of novel immunotherapeutic approaches to HIV infection.

Adult↗

PubMed2004

Negative regulation of hepatocellular carcinoma cell growth by signal regulatory protein alpha1.

Signal regulatory protein (SIRP) alpha1 is a member of the SIRP family that undergoes tyrosine phosphorylation and binds SHP-2 tyrosine phosphatase in response to various mitogens. The expression levels of SIRPalpha1 were decreased in HCC tissues, compared with the matched normal tissues. Exogenous expression of wild type SIRPalpha1, but not of a mutant SIRPalpha1 lacking the tyrosine phosphorylation sites, in SIRPalpha1-negative Huh7 human HCC cells resulted in suppression of tumor cell growth both in vitro and in vivo. Treatment of Huh7 transfectants with EGF or HGF induced tyrosine phosphorylation of SIRPalpha1 and its association with SHP-2, which were accompanied by reduced ERK1 activation. Expression of SIRPalpha1 significantly suppressed activation of NF-kappaB and also sensitized Huh7 cells to TNFalpha or cisplatin-induced cell death. In addition, SIRPalpha1-transfected Huh7 cells displayed reduced cell migration and cell spreading in a fashion that was dependent on SIRPalpha1/SHP-2 complex formation. In conclusion, a negative regulatory effect of SIRPalpha1 on hepatocarcinogenesis is exerted, at least in part, through inhibition of ERK and NF-kappaB pathways.

Antigens, Differentiation↗

PubMed2004

Experimental model for irradiating a restricted region of the rat brain using heavy-ion beams.

Heavy-ion beams have the feature to administer a large radiation dose in the vicinity of the endpoint in the beam range, its irradiation system and biophysical characteristics are different from ordinary irradiation instruments like X-rays or gamma-rays. In order to get clarify characteristic effects of heavy-ion beams on the brain, we have developed an experimental system for irradiating a restricted region of the rat brain using heavy-ion beams. The left cerebral hemispheres of the adult rat brain were irradiated at dose of 50 Gy charged carbon particles (290 MeV/nucleon; 5 mm spread-out Bragg peak). After irradiation, the characteristics of the heavy-ion beams and the animal model were studied. Histological examination and measurement showed that extensive necrosis was observed between 2.5 mm and 7.5 mm depth from the surface of the rat head, suggesting a relatively high dose and uniform dose was delivered among designed depths and the spread-out Bragg peak used here successfully and satisfactorily retained its high-dose localization in the defined region. We believe that our experimental model for irradiating a restricted region of the rat brain using heavy-ion beams is a good model for analyzing regional radiation susceptibility of the brain.

Animals↗

PubMed2004

Prophylaxis of neonatal respiratory distress syndrome by intra-amniotic administration of pulmonary surfactant.

BACKGROUND: Neonatal respiratory distress syndrome (NRDS) is caused by a deficiency in pulmonary surfactant (PS) and is one of the main reasons of neonatal mortality. This study was conducted to evaluate the efficacy and safety of intra-amniotic administration of pulmonary surfactant for prophylaxis of NRDS. METHODS: Forty-five pregnant women who were due for preterm delivery and whose fetuses' lungs proved immature were divided into two groups. Fifteen women (study group) were administered one dose of pulmonary surfactant injected into the amniotic cavity and delivered within several hours. Nothing was injected into the amniotic cavity of 30 women of the control group. The proportion of neonatal asphyxia, NRDS, mortality and the time in hospital were analyzed to determine if there was any difference between the two groups. RESULTS: There was no significant difference between the two groups for neonatal asphyxia. Foam tests showed that higher proportion of neonates in the study group than in the control group (56.3% vs 13.3%, P < 0.05) had lung maturity. A greater number of control neonates (11/30, 32.3%) had NRDS, compared with the neonates given PS via the amniotic cavity before delivery (1/16, 6.3%, P < 0.05). The neonates in the study group spent nearly 10 days less in hospital than the control group [(32.4 +/- 7.6) days vs (42.0 +/- 15.7) days, P < 0.05], but the difference in mortality between the two groups was not statistically significant. CONCLUSIONS: Intra-amniotic administration of pulmonary surfactant can significantly reduce the proportion of NRDS and the time in hospital of preterm neonates. Whether this method can reduce the mortality of preterm neonates needs to be evaluated further. Intra-amniotic administration of pulmonary surfactant provides an additional effectual means for NRDS prophylaxis.

Amnion↗

PubMed2004

[Susceptibility change to HBV in primary culture of first trimester human fetal hepatocytes].

OBJECTIVES: By culturing primary early (8 to 12-weeks-old) human fetal hepatocytes with different conditions, to study the status of cell susceptibility to HBV. METHODS: During primary culture of 10-weeks-old human fetal hepatocytes with serum-free medium adding different differentiation-induced ingredients, to inoculate cell with HBV at certain time. Cell shape, function and markers of HBV infection are measured. RESULTS: 6 days after seeding, markers of mature hepatocytes are observed in cells cultured with 2.5mmol/L phenobarbital sodium, and these cells show susceptibility to HBV. Other ingredients cannot render hepatocytes susceptible to HBV. CONCLUSION: Phenobarbital sodium induces differentiation and susceptibility to HBV in primary culture of early human fetal hepatocytes.

Cell Differentiation↗

PubMed2004

[Analysis of T cell repertoire in children with acute B lymphoblastic leukemia].

OBJECTIVE: The complementarity determining region 3 (CDR3) of T cell receptor (TCR) is the place through which T cells connect to the antigen. The lengths and DNA sequences of CDR3s are different according to different T cell clones. This leads to a diverse TCR CDR3 repertoires which can reflects the functional status of T cells precisely. This study aimed at elucidating the abnormality of TCR beta chain variable region (BV) CDR3 repertoires of children with acute B lymphoblastic leukemia, the pathogenesis of leukemia associated with T cell dysfunction and the immuno-reconstruction of T cells after the chemotherapy. METHODS: Twelve children aged from 3 to 13 years (average 4.50 +/- 3.78 years) with acute B lymphoblastic leukemia before chemotherapy and 8 healthy control donors aged from 6 to 16 years (average 10.30 +/- 3.00 years) were enrolled. Four of 12 patients were studied for the second time 3 months after complete remission (CR). Reverse transcription-polymerase chain reaction (RT-PCR) and polyacrylamide sequencing gel electrophoresis were used to detect the diversity of TCR BV CDR3 repertoires of these children. RESULTS: (1) The expression of BV2 and BV3 in 12 children increased and BV17 and BV18 decreased before the chemotherapy as compared with controls (P < 0.05). There were 4 children with a lower level expression of BV21 before the chemotherapy, and much lower level expression was found after the remission. (2) Normally each lane contained eight to ten bands, which represented unique CDR3 sizes for a given TCR BV family. Bands differed in size by 3 nucleotides and generally form a Gaussian distribution. There were 14% TCR BV families with abnormal CDR3 length distribution in 12 patients before therapy, which was significantly higher than that of controls (5.5%, P < 0.05). Restricted CDR3 length distribution was observed in BV14, BV1, BV16, BV20, BV13.1, BV13.2 and BV6. Every abnormal BV family recovered to normal Gaussian distribution 3 months after CR. CONCLUSION: T lymphocytes in children with acute B lymphoblastic leukemia revealed markedly skewed repertoires, which suggests the abnormality of T cell functions. Most abnormal T cell repertoires recovered to normal Gaussian distribution 3 months after the first CR, which suggests the immunological reconstitution of T cell repertoires.

Adolescent↗

PubMed2004

[Construction and functional study of truncated beta catenin genes].

AIM: To observe the subcellular location and the change of the transcriptional activity of truncated beta catenins in mammalian cells. METHODS: The full length wild type beta catenin gene was cloned by RT-PCR. The truncated beta catenins were constructed by deleting the N terminal, the C terminal or the Armadillo domain sequences, and were inserted into the EGFP expression vector. After they were transfected into 293 cells, the transcriptional activity of truncated beta catenins in 293 cells was detected by dual luciferase reporter system. The subcellular location of truncated beta catenin in transfected COS7 cells was observed under fluorescence microscope. RESULTS: The eukaryotic expression vector containing truncated beta catenin gene and expression vector of truncated beta catenin gene fused with EGFP gene were constructed successfully. C terminus-deleted beta catenin localized mainly in the cytoplasm of transfected COS7 cells, and the transcriptional activity of the N terminus- and the C terminus- deleted beta catenins was lower than that of the wild type beta catenin in transfected 293 cells. CONCLUSION: The different locations of truncated beta catenins in transfected COS7 cells suggest that the truncated ones play different roles in the transcriptional activity.

Animals↗