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Biomedical subjects

Hui Zhang

Publications and source records attributed to Hui Zhang.

At least 379 records · Page 21Linked to original sources
PubMed2002

Single domain antibody to human telomerase catalytic subunit: preparation and characterization.

OBJECTIVE: To develop a recombinant single domain antibody against hTERT, human telomerase catalytic subunit. METHODS: A previously prepared His-tagged hTERT fusion protein was used as the antigen, and the variable regions in heavy chain (VH) of immunized mice were RT-PCR amplified and cloned into the pCANTAB 5E, a phagemid vector. By transfection, the display library of mouse VH was developed. The candidate clones were selected by affinity panning, and soluble VH were obtained after expression in E. coli, HB2151. The resultant single VH antibodies were characterized on their binding potentials by western blotting. RESULTS: An about 350 bp VH fragment was amplified from spleen cells of mice immunized by His-tagged hTERT and expressed by phage displayed as VH library. The size of the library was 8 x 10(4). After three rounds of affinity panning, 4 independent clones were chosen and consequently expressed as soluble single domain antibodies (Mr = 16 000). In Western blot analysis, the single domain antibody from 2 of 4 clones proved to react with the His-tagged hTERT fusion protein (Mr = 167 000) without dependence of His-tags and also detect the native hTERT (Mr = 127 000) extracted from the human HeLa cancer cell line. DNA sequencing showed both of the single domain antibodies were encoded by the heavy chain variable region of the mouse. CONCLUSIONS: The single domain antibodies developed were hTERT recognizable and hTERT specific, thus providing a basis for application of recombinant single domain antibody in inhibition of telomerase activity and anticancer therapy.

Amino Acid Sequence↗
PubMed2002

Contents of four active components in different commercial crude drugs and preparations of danshen (Salvia miltiorrhiza).

AIM: To detect the contents of four active components of Salvia miltiorrhiza in various commercially available danshen crude drugs and preparations. METHODS: Commercially available danshen crude drugs from different sources, as well as danshen pills and intravenous injection preparations containing danshen alone or in combination with other herbs were collected. The composition of these danshen samples was analyzed using HPLC. Specifically, the amounts of magnesium tanshinoate B (MTB), danshensu, isotanshinone HA, and cryptotanshinone were determined. In some of these samples, the content of MTB was further confirmed by liquid chromatography-tandem mass spectrometer (LC-MS)/MS method. RESULTS: There were great variations in the amount of the four active ingredients in the commercially available danshen crude drugs and drug preparations in this study. The amount of MTB was the highest among the four components measured in the crude drugs. However, the amounts of MTB in all danshen preparations were much lower than those in crude drugs. The 2 lipophilic components, isotanshinone HA and cryptotanshinone, were very low or not detectable in both injection and oral preparations. CONCLUSION: MTB can be used to standardize the various forms of danshen crude drugs and drug preparations from different sources. In view of the variation in the amounts of MTB and other components, improvement in the production methods of danshen preparations is essential to ensure consistent amount of its active ingredients and reproducible pharmacological actions.

Chromatography, High Pressure Liquid↗
PubMed2002

[Computer-aided tissue expansion 3D profilometry and surgery planning system].

OBJECTIVE: To develop and evaluate the computer-aided system in measurement of expanded skin and preoperative planning. METHODS: Stereophotogrammetric technique was used to gain the 3D image-pairs, from which the contours of the expanded sites were restored. The 3D surface data were provided to the specially developed "computer-aided tissue expansion 3D profilometry and surgery planning system", to calculate the expansion area and help the preoperative design. RESULTS: The system has been applied clinically in 16 tissue expansion sites of 11 patients with fairly good results since March 1999. Compared with the traditional method, this system is accurate, repeatable and feasible. CONCLUSION: This technique is useful and promising for improving the operation of tissue expansion.

Adult↗
PubMed2002

[Finite element analysis of shape memory alloy intrasegmental fixator for lumbar spondylolysis].

OBJECTIVE: To study the tensile strength of shape memory alloy intrasegmental fixator and tensile stress distribution in the device during force loading with finite element method (FEM). METHODS: The designed parameters, scanning image, and mechanical properties of shape memory alloy intrasegmental fixator were input into computer for the construction of the FEM model of the device in inherent coordinate of ANSYS. The model was extended with restriction in different parts, and the tensile strength and the distribution of tensile stress in the model was calculated. RESULTS: When the device was loaded with pulling force to induce a relative displacement of 2 mm between the 2 hooks along the two midpoints, the pull was about 281 N, and the tensile stress concentrated more on the middle of device than on the two sides. CONCLUSION: The shape memory alloy intrasegmental fixator is strong enough against tensile stress, which concentrates in the middle portion of the device where fatigue breakage is liable to occur when excessive force is loaded.

Alloys↗
PubMed2002

[Cloning and expression of heavy chain variable region genes against telomerase protein hTERT].

Single domain antibodies against telomerase protein hTERT were prepared by technique of displayed on the surface of recombinant bacterio phages. Total RNA of spleen lymphocytes were extracted from mice immunized recombinant hTERT and transcripted to cDNA. First-strand cDNA was used as a template, heavy chain variable region genes against hTERT were amplified with VHfor and VHback primers by PCR technique. Amplification reaction yielded a fragment about 350 base pairs in length. Amplified cDNA were cloned into the vehide of bacteriophage PCANTAB 5E, the phagemid containing VH gene transformed into competent E. coli TG1, in the presence of helper phage M13K07, VH-g3 fusion proteins were display on the surface of recombinant phages. The phage carrying VH genes that encode binding activities could be detected directly with DOT BLOT. Single domain antibodies were generated successfully and had binding activities with hTERT. Results suggest that phage display technique be a new way of making antibodies. VH genes were cloned successfully, which could provide possibility for futher preparing single-chain antibodies(ScFv) anti-hTERT.

Animals↗
PubMed2002

[Study on the effects of cooking oil fume condensate on the DNA integrity].

The aim of this study was to study the DNA damage mechanisms of cooking oil fumes (COF) in vitro. The colorimetric MTT reduction assay was adopted to measure the effects of the cytotoxicity of COF condensate on type II pneumocytes from the lungs in the rats. The condensate of COF was of the dose-responsive effect on cell-inhibit rate to some extent (r = 0.943, P < 0.01). There is distinctive cytotoxicity on type II pneumocytes when concentration is higher than 20 micrograms/ml. The genotoxicities of COF condensate to type II pnemocytes were studied by modified alkaline single-cell gel using a electrophoresis(SCGE) assay(comet assay), the maximum concentration of condensate is below the concentration of cytotoxicity. The results showed that the condensate of COF was of the dose-responsive effect on the type II pneumocytes DNA damage to some extent(r = 0.918, P < 0.05) at the dosage of 0-5 micrograms/ml. The DNA damage reach to the maximum at the dosage of 10 micrograms/ml. The damaged DNA could be restored after been cultured for 2 hours. Calf thymus DNA cross-link after the administration of COF condensate were measured with ethidium bromide assay. It was found that condensate of COF was of the dose-responsive effect on the calf thymus DNA cross-links to some extent(r = 0.963, P < 0.01). The above results suggested that cooking oil fume condensate could induce DNA damage at much lower dosage and result in the increase of DNA cross-links in a certain concentration.

Air Pollution, Indoor↗
PubMed2002

[The expanded distant skin flap and its application].

OBJECTIVE: To summarize and present the experiences and results of the expanded distant skin flaps used in plastic and reconstructive operations. METHODS: 102 patients who had undergone expanded distant skin flap transfer were reviewed and followed up. RESULTS: Good results were obtained. Especially when there was no sufficient normal skin close to the lesion or defect, the distant skin flaps were employed. The expanded distant skin flap can be directly transferred as a pedicle skin flap or an island skin flap. It can be indirectly transferred with an intermediary carrier or as a free skin flap. CONCLUSION: The expanded distant skin flaps have many advantages, indications, worthy of recommendation.

Humans↗
PubMed2002

[Study on vertebral degenerations of coal miners with low back pain by means of computerized tomography].

OBJECTIVE: To study lumbar vertebral degenerations of coal miners with low back pain. METHODS: 40 underground miners with low back pain, aged from 30 to 50 years and employed for a length from 10 to 30 years, were taken as observation group. 30 ground workers without low back pain but with almost the same age, employment length and height etc. were selected as control group. Intervertebral discs at L3/L4, L4/L5, L5/S1 were scanned with computerized tomography, comparing herniated discs, sagittal diameter of vertebral canal, height of lateral recess, vertebral hypertostosis, ligament hypertrophy and calcification between two groups. RESULTS: L3/L4, L4/L5, L5/S1 herniated discs and narrow lateral recess in observation group(0.33 +/- 0.15, 0.53 +/- 0.25, 0.45 +/- 0.18 and 0.40 +/- 0.08, 0.31 +/- 0.05, 0.37 +/- 0.07) were more serious than that in control group(0.28 +/- 0.11, 0.32 +/- 0.21, 0.37 +/- 0.19 and 0.42 +/- 0.10, 0.43 +/- 0.07, 0.40 +/- 0.06), but only with significant difference at L4/L5 (P < 0.01). Sagittal diameter of vertebral canal in observation group is narrower than that in control group but of little significance(P > 0.05). Cases of vertebral hyperostosis, ligament hypertrophy and calcification were found more frequent in observation group(45.00%, 42.50%, 22.50%) than in control group(23.33%, 16.67%, 16.67%), but only ligament hypertrophy was remarkable(P < 0.05). CONCLUSIONS: As compared with control group lumbar vertebral degenerations are more serious in underground miners with manifestations like herniated disc and narrow lateral recess mainly at L4/L5.

Adult↗
PubMed2002

[The 3D PACS image system based on pipeline framework].

We put forward an image rendering system based on pipeline framework for processing and displaying medical images. Compared to original computer graphics algorithms divided into volume rendering and surface rendering, this framework can effectively comprehend methods of computer graphics and image processing, import some new concepts such as vertex buffer, pixel buffer and texture buffer. We implement Shaded Surface Display, Maximum Intensity Projection, Digitally Reconstructed Radiography, Multi planar Reformation, Curved Planar Reformation and Interactive Virtual Endoscopy in our new developed PACS image system.

Algorithms↗
PubMed2002

[DICOM in radiotherapy].

Digital Image Communication in Medicine (DICOM) defines a standard method to store and transmit digital medical image information, in which there is a piece of implemented protocol named DICOM-RT that specially addresses both the transmission of radiation therapy image data and the ancillary data. In this paper, we firstly introduce the DICOM-RT with the emphases on its components, relationship with radiotherapy and how to produce the DICOM-RT object that refer to some certain radiotherapy information. Then we expatiate on the impact that benefits from applying DICOM-RT to radiotherapy, with an aid to accelerate its application in China.

Computer Communication Networks↗
PubMed2001

Abnormalities in oxidative processes in non-neuronal tissues from patients with Alzheimer's disease.

Overwhelming evidence demonstrates that oxidative stress occurs in brains from patients with Alzheimer's Disease (AD). Whether the oxidative stress is secondary to neurodegeneration, or if it underlies the pathology is not clear. The persistence of AD-related abnormalities in oxidative processes in non-neuronal tissues, including cultured cells, infers that an imbalance in production and removal of reactive oxygen species is an inherent property of cells from AD patients. These results suggest that changes in oxidative processes in AD cells could precede and/or cause AD-related neuropathology. Abnormalities in oxidative processes may also cause changes in signal transduction systems such as calcium that occur in cells from AD patients. The ability to manipulate oxidative processes in peripheral tissues, especially cultured cells, from AD patients should facilitate a mechanistic understanding of the changes in oxidative processes in AD brain. The use of peripheral tissues has the potential to identify both state and trait dependent diagnostic markers, which could be used as endpoints for selecting treatments or monitoring therapeutic effectiveness.

Journal Article↗
PubMed2000

Expression of Reverse Cholesterol Transport Pathway Associated Protein Genes in Skeletal Muscle.

Viral and nonviral vectors containing apoAI, apoE or LCAT genes were constructed and transfected into myogenic cells in vitro or injected directly into mouse skeletal muscle. The expression efficiencies of these vectors were assaied to investigate the possibility of ectopic expression of these genes in skeletal muscle and to develop a safe and convenient gene therapy method for atherosclerosis. The results showed that the primary cultured mouse myoblasts, C2C12 cells transfected with pCMVapoE3 expressed human apoE3 successfully and the expressed product was secreted into the medium. Mouse skeletal muscle efficiently expressed apoE3 in vivo after direct plasmid injection. The expression level of Ad-RSV-apoAI in primary cultured mouse myoblasts was correlated with virus titer. Human apoAI was synthesized in mouse skeletal muscle by direct injection of recombinant virus and was secreted into blood continuously up to 30 days functional LCAT was expressed by C2C12 and 293 cells transfected with conventional vector or recombinant AAV plasmid DNA. The expression efficiency of recombinant AAV plasmid DNA was 2-5 times higher than that of conventional plasmid vector. The above results provided experimental data for further studying and developing a gene therapy method for atherosclerosis by enhancement of reverse cholesterol transport using skeletal muscle as target.

Journal Article↗
PubMedDate not supplied

High sensitive fluorophotometric determination of nucleic acids with Pyronine G sensitized by N,N-dimethylformamide.

In Tris-HCl buffer (pH 8.0), the fluorescence of Pyronine G emitted at 552 nm was quenched by nucleic acids when excited at 525 nm. Adding N, N-dimethylformamide (DMF) as a sensitive media can enhance the sensitivity greatly. Based on the fluorescence reactions sensitive fluorimetric methods for nucleic acids at nanogram levels were proposed. Under the optimum conditions, the calibration curves were linear in the range of 0.0032 - 2.5 microg mL(-1) for ct DNA and 0.0024 - 2.5 microg mL(-1) for hs DNA. The limits of determination were 3.2 ng mL(-1) and 2.4 ng mL(-1) respectively. This method has good selectivity and high sensitivity. It has been applied to the determination of DNA in the synthetic samples and real samples with satisfactory results.

Animals↗
PubMedDate not supplied

Eyelid fusion and epithelial differentiation at the ocular surface during mouse embryonic development.

PURPOSE: To investigate epithelial differentiation at the ocular surface of the developing mouse eye by examining temporal and spatial changes in the expression of specific keratins. METHODS: Ocular tissues, including the entire eyeball, conjunctiva, and eyelid, of mouse embryos at embryonic day (E) 12.5 to E18.5 as well as of adult mice were examined by hematoxylin-eosin staining and by immunohistochemistry with antibodies to keratins K4, K10, K12, and K14. RESULTS: Hematoxylin-eosin staining revealed that eyelid fusion occurred at E17.5. Keratin immunohistochemistry demonstrated that: (1) K4 was expressed before K12, which in turn was expressed before K10; (2) expression of K4, K12, and K14 was spatially heterogeneous in the epithelia of the eyelid invaginations before eyelid fusion, but thereafter was continuous and homogeneous in the entire conjunctival epithelium, corneal epithelium, and basal cell layer of the surface epithelia, respectively; and (3) K10 immunoreactivity was not detected before eyelid fusion but was apparent in the epidermis of the eyelid thereafter. CONCLUSIONS: Eyelid fusion is a critical period for differentiation of the ocular surface ectoderm into the epithelia of the conjunctiva, cornea, and eyelid skin. The conjunctival epithelium differentiates before the corneal epithelium, which in turn differentiates before the eyelid epidermis.

Animals↗
PubMedDate not supplied

Web-based tools for mining the NCI databases for anticancer drug discovery.

In this paper, we describe the development of a set of integrated Web-based tools for mining the National Cancer Institute's (NCI) anticancer databases for anticancer drug discovery. For data mining, three different correlation algorithms were implemented, which included the commonly used Pearson's correlation algorithm available from the NCI's COMPARE program, the Spearman's and Kendall's correlation algorithms. In addition, we implemented the p-value test to evaluate the significance of the correlation results. These Web-based data mining tools allow robust analysis of the correlation between the in vitro anticancer activity of the drugs in the NCI anticancer database, the protein levels and mRNA levels of molecular targets (genes) in the NCI 60 human cancer cell lines for identification of potential lead compounds for a specific molecular target and for study of the molecular mechanism action of a drug. Examples were provided to identify PKC ligands using a lead compound and to identify potential ErbB-2 inhibitors using the mRNA levels of ErbB-2 in the NCI 60 tumor cell lines.

Antineoplastic Agents↗
PubMedDate not supplied

Blockade of B7-H1 with sPD-1 improves immunity against murine hepatocarcinoma.

BACKGROUND: The B7-H1/PD-1 pathway has been demonstrated to be involved in tumor evasion. In a previous study, we constructed a eukaryotic expression plasmid (pPD-1A), which expresses soluble PD-1 (sPD-1). In this study, the question of whether or not the blockade of B7-H1 with sPD-1 in vivo and vitro can improve antitumor immunity was investigated. MATERIALS AND METHODS: The proliferation of lymphocytes activated by dendritic cells (DCs), which were treated with sPD-1 in vitro, was detected with MTT colorimetry. Mice inoculated with H22 cells were treated by intramuscular injection with pPD-1A. The mRNA expression was analyzed with RT-PCR. RESULTS: The early activation of lymphocytes in vitro was partly improved by sPD-1 blockade. The growth of H22 cells was inhibited significantly after pPD-1A administration. The mRNA expression of 4-1BB, B7.1, IFN-gamma and TNF-alpha of lymphocytes was up-regulated and that of OX40 and IL-10 was down-regulated after pPD-1A administration. CONCLUSION: Blockade of the PD-1/B7-H1 pathway with sPD-1 may be a promising strategy for immunotherapy for hepatocarcinoma. Both cytokines and co-stimulatory molecules of lymphocytes could be regulated by sPD-1 blockade.

Animals↗