Biomedical subjects

Z Hu

Publications and source records attributed to Z Hu.

At least 73 records · Page 4Linked to original sources

PubMed2001

Expression of multidrug-associated protein, P-glycoprotein, P53 and Bcl-2 proteins in bladder cancer and clinical implication.

The expression of multidrug resistant proteins in bladder cancer and clinical implication was studied. Expression of multidrug-associated protein (MRP), P-glycoprotein (P-gp), P53 and Bcl-2 proteins were detected by using immunohistochemical method in 40 specimens of bladder transitional cell carcinoma. The results showed that the positive rate of MRP, P-gp, P53 and Bcl-2 was 52.5%, 57.5%, 47.5% and 62.5% respectively. The positive rate of MRP, P-gp, P53 and Bcl-2 in the grade I, II and III of tumors was 46.3%, 38.5%, 38.5%, 23.1%; 52.9%, 39.8%, 47.1%, 76.4%; 60.0%, 80.0%, 60.0%, 90.0% respectively. The positive rate of MRP, P-gp, P53 and Bcl-2 in 24 primary tumor specimens was 37.5%, 41.7%, 33.3%, 45.8% and that in 16 cases in recurrent specimens receiving chemotherapy 75.0%, 81.3%, 68.8%, 87.5% respectively. It was suggested the positive rate of MRP, P-gp, P53 and Bcl-2 was increased with the advance of tumor grade. The positive rate of four proteins in all recurrent cases was significantly increased (P < 0.05). The expression of MRP, P-gp, P53 and Bcl-2 proteins might be the important factors for chemotherapy failure.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

Prediction of programmed-temperature retention values of naphthas by wavelet neural networks.

The wavelet neural network (WNN) was used to predict the programmed-temperature retention values of naphthas. In WNN, a Morlet mother wavelet was used as a transfer function, and the convergence speed was faster than other neural networks. Sixty-four compounds (selected randomly from 94) were used as a training set, and the 30 remaining compounds were used as a test set. A very satisfactory result was obtained only after about 8000 training epochs. The other two methods, the artificial neural network (ANN) and the Simpson integral method, were also used for this study. The comparison of results obtained from three methods showed that the WNN is the most suitable tool in predicting programmed-temperature retention values of naphthas, consequently this method can be used to provide reliable data for the petrochemical industry.

Journal Article↗

PubMed2001

Prediction of enthalpy of alkanes by the use of radial basis function neural networks.

A new method for the prediction of enthalpy of alkanes between C6 and C10 from molecular structures has been proposed. Thirty five calculated descriptors were selected for the description of molecular structures. The first four scores of Principle Component Analysis on the calculated descriptors were used as inputs to predict the enthalpy of alkanes. Models relating relationships between molecular structure descriptors and enthalpy of alkanes were constructed by means of radial basis function neural networks. To get the best prediction results, some strategies were also employed to optimise the learning parameters of the radial basis function neural networks. For the test set, a predictive correlation coefficient of R = 0.9913 and root mean squared error of 0.5876 were obtained.

Journal Article↗

PubMed2001

Research and prediction of coordination reactions between CPA-mA and some metal ions using artificial neural networks.

The complex relationship between maximum absorption wavelength (lambda(max)), molar absorptivity (epsilon) of the coordination compounds formed from m-acetyl-chlorophosphonazo (CPA-mA) and the metal ions, the acidity of coordination reaction, some properties of metal ions and the properties of more than 20 coordination compounds were studied using artificial neural networks with extended delta-bar-delta EDBD back learning algorithms in this paper. Six parameters: the pH of coordination reactions, metal ion radius (R), relative atomic weight (Wt), ionic electronic energy (E), metal ion standard Gibbs' free energy (deltaG0) and hard-soft acid-base dual scale (f) were used as input parameters, to predict the lambda(max) and epsilon of the coordination compounds. The structures of networks and the learning times were optimized. The best networks structure is 6-7-2. The optimum number of learning times is about 160,196. It is shown that the maximum relative error is no more than 6% in the testing set. The trained networks are used to simulate the complicated relations between the metal ion properties, coordination reaction conditions and the properties of coordination compounds. This optimized networks have been used for the prediction of the lembda(max) and epsilon of coordination compounds formed from Tb3+, Ho3+ with CPA-mA separately and with satisfactory results.

Journal Article↗

PubMed2001

Topological regulation of cell division in E. coli. spatiotemporal oscillation of MinD requires stimulation of its ATPase by MinE and phospholipid.

Topological regulation of cell division in E. coli requires positioning a cell division inhibitor, MinC, at the poles of the cell, thus restricting the potential for division to midcell. This positioning is achieved through a rapid oscillation of MinC from pole to pole, a process requiring MinD and MinE. However, the mechanistic basis for this oscillation is not known. Here we report that MinE stimulates MinD ATPase activity, but only in the presence of phospholipid vesicles. Analysis of MinE mutants demonstrates that this stimulation is required for MinD oscillation and suggests that the level of stimulation determines the period of the oscillation. A model is presented in which the requirements for the MinD ATPase contribute spatial and temporal inputs that provide the mechanistic basis for the oscillation.

Adenosine Triphosphatases↗

PubMed2001

Fluorescence characteristic study of the ternary complex of fluoroquinolone antibiotics and cobalt (II) with ATP.

The results from the measurement of the fluorescence spectra of fluoroquinolone antibiotics including ofloxacin (OF), norfloxacin (NOR) and ciprofloxacin (CIP) complexed with cobalt (II) and ATP give information concerning the antibiotics-nucleotide interactions. From the fluorescence spectral data, it appears that the fluoroquinolone antibiotic cannot directly complex with ATP but indirectly complex with cobalt (II), which is playing an intermediary role. The interaction of fluoroquinolone antibiotic with the nucleotide occurs mainly through the phosphate group. The conclusion offers a more complete mechanism, which is important for understanding the interaction of these drugs with DNA.

Adenosine Triphosphate↗

PubMed2001

Five new insecticidal sesquiterpenoids from Celastrus angulatus.

Five new sesquiterpene polyol esters were isolated from the root bark of Celastrus angulatus by bioassay-guided fractionation. Their structures were determined by spectral data interpretation as 1alpha,2alpha,6beta,8beta,13-pentaacetoxy-9beta-benzoyloxy-4beta-hydroxy-beta-dihydroagarofuran (1), 1alpha,2alpha,6beta-triacetoxy-8alpha-(beta-furancarbonyloxy)-9beta-benzoyloxy-13-isobutanoyloxy-4beta-hydroxy-beta-dihydroagarofuran (2), 1alpha,2alpha,6beta-triacetoxy-8beta-isobutanoyloxy-9beta-(beta-furancarbonyloxy)-13-(alpha-methyl)butanoyloxy-4beta-hydroxy-beta-dihydroagarofuran (3), 1alpha,2alpha,6beta-triacetoxy-8alpha,13-diisobutanoyloxy-9beta-benzoyloxy-4beta-hydroxy-beta-dihydroagarofuran (4), and 1alpha,2alpha,6beta-triacetoxy-8alpha-isobutanoyloxy-9beta-benzoyloxy-13-(alpha-methyl)butanoyloxy-4beta-hydroxy-beta-dihydroagarofuran (5). Compounds 1-5 exhibited insecticidal activity against the larval of Mythimna separata.

Animals↗

PubMed2001

Nucleotide sequence and transcriptional analysis of a putative basic DNA-binding protein of Helicoverpa armigera nucleopolyhedrovirus.

A putative basic DNA-binding protein (BDBP) gene was identified in the fragment EcoRI-K of the Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HearNPV) genome. The ORF is 330 nucleotides long encoding a basic protein of 109 amino acids with a molecular mass of 11.6 kDa. It is the first BDBP identified in single nucleocapsid NPVs and a homologue of Autographa californica MNPV (AcMNPV) P6.9. A consensus late transcription motif, ATAAG, was found at 57 nt upstream of the translational start codon and a polyadenylation signal was observed at 172 nt downstream of the stop codon. A major transcript of 620 nt was first observed in HearNPV-infected Hz2e5 cells 16 h post infection. Primer extension analysis revealed that this transcript initiated from the first residue of the consensus ATAAG late transcription start motif. Comparison with other baculoviral BDBPs showed that they all contained two conserved cAMP- and cGMP-dependent protein kinase phosphorylation motifs, R-R-R-S. The HearNPV P6.9 homologue is the longest BDBP found so far in baculoviruses.

Amino Acid Sequence↗

PubMed2001

Study of the reaction of proteins with Beryllon II-AlIII by the Rayleigh light scattering technique and its application.

The determination of proteins with tetrasodium 2-(3,6-disulfo-8-hydroxynaphthylazo)-1,8-dihydroxynaphthalene-3,6-disulfonate (Beryllon II) by Rayleigh light scattering (RLS) was studied. The weak RLS of the Beryllon II-bovine serum albumin (BSA) complex can be greatly enhanced by the addition of Al3+ in the pH range 5.6-7.2; there was a maximum RLS platform at 400-420 nm. Based on the reaction between Beryllon II, Al3+ and proteins, a new method for the determination of proteins was developed. This method is very sensitive [0.20-41.42 micrograms ml-1 for BSA and 0.18-48.15 micrograms ml-1 for human serum albumen (HSA)], rapid (< 2 min), simple (one step) and tolerant towards most interfering substances. The effects of different surfactants were also examined. Four samples of protein in human serum were determined; the maximum relative error was no more than 5% and the recovery was 96-105%.

Aluminum↗

PubMed2001

p47phox is required for atherosclerotic lesion progression in ApoE(-/-) mice.

NADPH oxidase is upregulated in smooth muscle cells (SMCs) in response to growth factor stimulation, concomitant with increased reactive oxygen species (ROS) production. We investigated the role of ROS production by NADPH oxidase in SMC responses to growth factors and in atherosclerotic lesion formation in ApoE(-/-) mice. SMCs from wild-type, p47phox(-/-), and gp91phox(-/-) mice differed markedly with respect to growth factor responsiveness and ROS generation. p47phox(-/-) SMCs had diminished superoxide production and a decreased proliferative response to growth factors compared with wild-type cells, whereas the response of gp91phox(-/-) SMCs was indistinguishable from that of wild-type SMCs. The relevance of these in vitro observations was tested by measuring atherosclerotic lesion formation in genetically modified (wild-type, p47phox(-/-), ApoE(-/-), and ApoE(-/-)/p47phox(-/-)) mice. ApoE(-/-)/p47phox(-/-) mice had less total lesion area than ApoE(-/-) mice, regardless of whether mice were fed standard chow or a high-fat diet. Together, these studies provide convincing support for the hypothesis that superoxide generation in general, and NADPH oxidase in particular, have a requisite role in atherosclerotic lesion formation, and they provide a rationale for further studies to dissect the contributions of ROS to vascular lesion formation.

Animals↗

PubMed2001

X-deficient woodchuck hepatitis virus mutants behave like attenuated viruses and induce protective immunity in vivo.

The X protein (HBX) of the hepatitis B virus (HBV) has been shown to be important for the establishment of HBV infection in vivo. Our previous studies suggested that interaction of HBX with the proteasome complex may underlie the pleiotropic functions of HBX. In this study, we generated a series of woodchuck hepatitis virus (WHV) X mutants, including mutants of the domain interacting with the proteasome, and studied their infectivity in woodchucks. Many of the mutants were defective in transactivation but none of them were completely replication defective in vitro. In vivo, all the wild-type and some X mutant-transfected animals demonstrated evidence of infection with anti-WHc and/or anti-WHs seroconversion. Most of the wild-type- and X mutant-transfected animals had transient viremia. Some animals were later challenged with infectious WHV. Animals inoculated with X mutants, including those with no serologic evidence of infection, were protected from the challenge, suggesting previous infection with resulting protective immunity. Our study demonstrates that the previously described functional domains of HBX are biologically important and the X-defective mutants, possibly as attenuated viruses, are not completely replication defective in vivo.

Animals↗

PubMed2001

Application of pressure-controlled colon delivery capsule to oral administration of glycyrrhizin in dogs.

A colon delivery system has been used to improve the bioavailability of glycyrrhizin, a glycoside of glycyrrhetic acid. The bioavailability of glycyrrhizin is low when administered in conventional oral galenic dosage forms because glycyrrhizin is enzymatically hydrolysed both in the stomach and in the intestine. It was reasoned that if large amounts of glycyrrhizin were directly delivered to the colon, enzymatic activity should be reduced due to saturation so that intact glycyrrhizin could be absorbed into the systemic circulation. Based on this assumption, pressure-controlled colon delivery capsules (PCDCs) were used as a colon delivery system. Eight types of glycyrrhizin solution were prepared and were introduced into PCDCs. After oral administration of the test PCDCs to beagle dogs, blood samples were obtained over 24 h and plasma glycyrrhizin concentrations were measured by an HPLC method. With PCDCs containing aqueous glycyrrhizin and propylene glycol solutions, plasma glycyrrhizin levels were extremely low and the bioavailabilities of glycyrrhizin were 0.6% and 0.4%, respectively. When Labrasol was added to both types of glycyrrhizin solution, the bioavailability was improved to 4.6% for aqueous solution and 3.8% for propylene glycol solution. When a surfactant, Polysorbate 80, was added in combination with Labrasol, synergistic effects were not obtained. Furthermore, dose-dependent effects of Polysorbate 80 were not obtained. Labrasol, which is a component of self-emulsifying drug delivery systems (SEDDS), has been shown to strongly improve the bioavailability of glycyrrhizin from the colon.

Administration, Oral↗

PubMed2001

Vascular expression of integrin-associated protein and thrombospondin increase after mechanical injury.

BACKGROUND: Integrin-associated protein (IAP) is a thrombospondin (TSP)-binding, Gi protein-coupled cell surface receptor. The vascular function of IAP has not been defined, and it is not known whether TSP and IAP are expressed at the same time in injured arteries. METHODS: Left brachial arteries of baboons were injured using balloon withdrawal technique. Arteries were harvested 1 week after injury, and immunohistochemistry and in situ hybridization were performed using standard techniques. Uninjured right brachial arteries served as a control. Proliferation studies were performed using cultured human aortic smooth muscle cells (SMC). RESULTS: We found significant IAP expression in the media and neointima 7 days after injury using BRIC-126, an immunoglobulin (Ig) G2b monoclonal antibody that recognizes IAP with high specificity. In contrast, IAP staining in the uninjured vessel was only observed in the endothelium. Concurrent with IAP expression, TSP mRNA and protein expression in the neointima and media was enhanced 1 week after injury. In cultured SMC, activation of IAP was sufficient to elicit a proliferative response. TSP-induced proliferation was inhibited by antibodies that block TSP binding to IAP and mimicked by 4N1K, a 10-amino acid peptide derived from the IAP binding site within the carboxyl terminus of TSP. CONCLUSIONS: Vascular expression of IAP and TSP increased after mechanical injury and activation of IAP elicited a proliferative response in cultured SMC. These findings support the hypothesis that IAP participates in vascular healing responses.

Animals↗

PubMed2001

Determination of nucleic acids with crystal violet by a resonance light-scattering technique.

For the first time, Crystal Violet (CV) was used to determine nucleic acid concentrations using the resonance light-scattering (RLS) technique. Based on the enhancement of the RLS of CV by nucleic acids, a new quantitative determination method for nucleic acids in aqueous solutions has been developed. At pH 5.03 and ionic strength 0.005 mol kg-1, the interaction of CV with nucleic acids results in three characteristic RLS peaks at 344.0, 483.0 and 666.0 nm. With 4.0 x 10(-5) mol l-1 of CV, linear relationships were found between the enhanced intensity of RLS at 666.0 nm and the concentration of nucleic acids in the range 0-2.5 micrograms ml-1 for herring sperm DNA, 0-4.0 micrograms ml-1 for calf thymus DNA and 0-4.5 micrograms ml-1 for yeast RNA. The limits of determination were 13.8 ng ml-1 for herring sperm DNA, 36.8 ng ml-1 for calf thymus DNA and 69.0 ng ml-1 for yeast RNA. The assay is convenient, rapid, inexpensive and simple.

Animals↗

PubMed2001

[Rapid detection of Mycobacterium tuberculosis resistance to rifampin using DNA chip].

OBJECTIVE: To develop a new method, DNA chip, which can be used for rapid detection of Mycobacterium tuberculosis resistance to RFP. METHODS: Designing probe according to the sequence of Mycobacterium tuberculosis rpoB gene and fabricating DNA chip. The DNA fragment which contains hot mutation sites of rpoB gene was labelled with cy5 fluorescence and amplified by PCR technique. Then it was hybridized with DNA chip. DNA sequence was used as the control. RESULTS: 14 strains were detected out of 17 randomly selected Mycobacterium tuberculosis resistant to RFP using DNA chip. The efficiency was 83%. A little bit DNA in the sick sputa was sufficient for drug resistance detection without being incubated. CONCLUSION: It showed higher specialty and sensitivity using DNA chip to detect Mycobacterium tuberculosis resistance to RFP. This method was rapid and accurate and could be used for clinical detection of RFP-resistant strains.

Antibiotics, Antitubercular↗

PubMed2001

[Relationships between soil-plant nutrition, quality of agricultural products and human and livestock health].

The abundant and insufficient situation of essential elements such as calcium magnesium, sulphur, zinc and iron and beneficial elements such as selenium and iodine in soils was reviewed, and the influences of these elements and organic matter on the quality of agricultural products and human and livestock health were discussed. The trends of future research in the field of soil element science and plant nutrition, in particular, the quality of agricultural products were prospected.

Animals↗

PubMed2001

[Application of rapid detection for Mycobacterium tuberculosis with phage splitting assay].

OBJECTIVE: To study the significance of rapid identification for Mycobacterium tuberculosis with phage splitting assay. METHODS: Strains of Mycobacterium tuberculosis, non-tuberculosis mycobacterium, non-mycobacterium and samples of sputum with pulmonary tuberculosis were rapidly detected by phage spot technique. RESULTS: The strains of Mycobacterium tuberculosis H37Rv, bovis and africanum were all positive. The results of 10 strains of non-tuberculosis mycobacterium and 7 strains of non-mycobacterium were negative. All of 30 clinical isolates from the patients of the pulmonary tuberculosis were positive. 19 of 20 sputum specimen of pulmonary tuberculosis, which were all positive detected by smear and culture, were positive. There were 15 specimen positive in 21 sputum with negative tested by smear and positive by culture. Besides, 5 of 19 sputum specimen with negative by smear and culture were positive detected by this method. CONCLUSION: The phage splitting assay can be used for rapid identification of Mycobacterium tuberculosis, which possesses high specificity and sensitivity for detection of Mycobacterium tuberculosis in sputum specimen.

Animals↗

PubMed2001

Erythrocyte membrane protein abnormalities in beta-thalassemia of the Li nationality in Hainan.

OBJECTIVE: To determine the composition of abnormal red cell membrane skeleton. METHODS: By sodium dodecyl sulphate polyacrylamide gel electrophoresis of ghostcorpuscles, we quantified the amount of protein by densitometric evaluation. RESULTS: The results showed that in beta-thalassemia, the amount of spectrin, 4.5 protein and globin significantly increased compared with the controls (26.05 +/- 1.46, 21.69 +/- 1.86; 22.87 +/- 5.61, 12.99 +/- 2.33; 15.23 +/- 3.31 and 4.97 +/- 2.73, respectively, P < 0.05). CONCLUSION: These data suggest that the erythrocyte membrane protein composition matched with globin in patients with beta-thalassemia of the racial Li minority are different from the normal control. These factors increase rigidity but decrease deformability of the beta-thalassemic red cell membrane, which may lead to hemolytic anemia.

China↗