Biomedical subjects

Lan Zhang

Publications and source records attributed to Lan Zhang.

49 records · Page 3Linked to original sources

PubMed2004

[Covert infection of severe acute respiratory syndrome in health-care professionals and its relation to the workload and the type of work].

OBJECTIVE: To study severe acute respiratory syndrome (SARS) covert infection in health-care professionals and its relation to work intensity and type of work. METHODS: Specific antibodies to SARS virus in 1 127 serum specimens from health-care professionals who had a close contact history with patients of SARS and 92 healthy persons were assayed with ELISA. RESULTS: The health-care professionals consisted of 287 men and 840 women, aged 21 - 55 years (mean 34 +/- 9 years). The overall positive rate of specific IgG and IgM was 2.57% (29/1 127); the positive rates in nurses, doctors and laboratory workers, and supervisors were 3.46%, 1.41%, 2.86%, respectively. 34.5% of the infected worked in the ICU, and 65.5% in the general wards. None of them presented clinical SARS. Medical examination was also carried out for 313 people who had close contact with the 29 antibody positive health care professionals, but no clinical SARS was found. CONCLUSIONS: Covert infection can be found in the health-care professionals and it showed no contagiousness. The positive rate of specific antibodies was higher in ICU where the work intensity was higher. The positive rate in nurses was higher than in doctors.

Adult↗

PubMed2004

[Expression of HSP70 induced by ketamine in the hippocampus of rat at different ages].

OBJECTIVE: This experiment was designed to explore the possible mechanism of the brain injury caused by ketamine. METHODS: Thirty-five adult SD rats randomly divided into a control group and 6 experiment groups were given intrapertioneal injections of normal saline, 20.0, 40.0, 60.0, 80.0, 100.0, 120.0 mg/kg of ketamine respectively. Another 35 SD rats at 0-10, 11-20, 21-30, 31-45, 46-60, 61-90, 91-120 days old were allocated to 7 corresponding age groups and were given intrapertioneal injection of ketamine 80.0 mg/kg. Immunocytochemistry was used to detect HSP70 expression in rat hippocampus, and MIAS-2000 photography analytic software was chosen to analyze HSP70 expression. RESULTS: Ketamine induced HSP70 expression in adult rat hippocampus. Below the dose of 80.0 mg/kg, ketamine induced higher level of HSP70 expression as the dose increased; however, above the dose of 80.0 mg/kg, ketamine induced lower level of HSP70 expression as the dose increased. Ketamine did not induce HSP70 expression in the rats under 20 days of age; it induced the same HSP70 expression in rats of 90 days and over; and analyses of the rats of 20-90 days revealed that the elder the rat is, the higher the HSP70 expression will be. CONCLUSION: Ketamine injures the neurons of rat hippocampus and induces the expression of HSP70, and the higher the dose is given, the more serious the injury is seen; and ketamine induces higher level of HSP70 expression in adult rats than in infant rats.

Age Factors↗

PubMed2004

[Molecular pharmacogenetic studies of drug responses to obsessive-compulsive disorder and six functional genes].

OBJECTIVE: To investigate the associations between the drug responses to obsessive -pulsive disorder (OCD) and six functional genes related with serotonin and dopamine. METHODS: One hundred and thirteen OCD nuclear families were collected. The OCD patients were treated with serotonin reuptake inhibitors (SRIs) for 8 weeks and the drug responses were assessed using the Yale-Brown obsessive-compulsive scale (Y-BOCS). The patients were divided into drug responders group and non-responders group according to the reducing rate of Y-BOCS score. The genotypes of six genes were determined with the Amp-FLP and Amp-RFLP techniques and analyzed by transmission disequilibrium test (TDT). The six genes are serotonin 2A receptor (5-HT2A), serotonin transporter (5-HTT), dopamine D2 receptor ( DRD2), dopamine D4 receptor (DRD4), catechol-O- methyltransferase (COMT) and monoamine oxidase A (MAOA). RESULTS: No association was found between the six genes and different drug responses groups. However, there was significant difference between the drug responders and non-responders in homozygosity at the 5-HT2A -1438G/A locus (chi(2)=4.69, P=0.03). CONCLUSION: The results suggested that the 5-HT2A may play some roles in the effects of drug treatment on OCD.

Adolescent↗

PubMed2004

[Effect of 1-MCP on senescence and quality in cold-stored edible podded pea].

The effects of 1-MCP (1-methylcyclo-propene) at 0.5, 1 and 2 muL/L on senescence and quality attributes in edible podded pea (Pisum sativum L.var.Saccharatum) during cold storage at 1 degrees C were investigated. The results indicated that treatments with 1 and 2 microL/L 1-MCP significantly inhibited respiratory rate, ethylene production and superoxide production, maintained higher levels of SOD, AsA-POD activities and chlorophyll and AsA contents, reduced the increases in MDA and fiber contents and decay index, thereby delayed the senescence process and quality deterioration. Treatment with 0.5 microL/L 1-MCP showed no significant effects on senescence and quality changes in harvested edible podded pea.

Cold Temperature↗

PubMed2004

[Study on removal of arsenic in drinking water by metal loaded materials].

OBJECTIVE: To study the effect of metal loaded multiporous materials on the removal of arsenic in drinking water. METHODS: Metal loaded materials were manufactured using active carbon, active alumina, silica gel and macroporous resin etc. as carriers and iron salts and zirconium salts etc. as activating reagents. Preparation condition as well as static and dynamic capacities of arsenic removal were examined. RESULTS: Active carbon and ferric nitrate were selected to prepare composite material for removal of arsenic in drinking water. Based on the state applicable limit of 0.05 mg/L for arsenic in drinking water, iron loaded active carbon tested in this study reduced arsenic at capacities of 2.94 mg/g for As(+3) and 2.56 mg/g for As(+5) in drinking waters spiked with 0.284 mg/L of As(+3) and 0.254 mg/L of As(+5) respectively. CONCLUSION: Iron loaded active carbon made from active carbon and ferric nitrate may remove arsenic in drinking water.

Aluminum Oxide↗

PubMed2004

[Effect of shenwu capsule on the peripheral blood lymphocyte DNA of rat model induced by beta-amyloid injection].

OBJECTIVE: To investigate the effect of the new Traditional Chinese Compound Shenwu Capsule on the damage of lymphocyte DNA and lipid peroxidation in peripheral blood of rats induced by beta-amyloid injection. METHOD: The animal model was made by injection of beta-amyloid25-35 into hippocampus of rats. DNA damage of lymphocytes was measured by the single cell gel electrophoresis (SCGE) combined with the laser scanning confocal microscopy (LSCM). The content of malondialdehyde (MDA) was determined by TBA assay. RESULT: Shenwu Capsule decreased the rate of the comet-like cell, comet-like cell lengh (TCL), and tail moment (TM) of lymphocytes in peripheral blood of model rats. Shenwu Capsule also declined the MDA content in serum of Abeta model rats. CONCLUSION: Shenwu Capsule has protective effect on peripheral blood lymphocyte DNA.

Amyloid beta-Peptides↗

PubMed2003

[Copper sorption and desorption by loess in water-sediment systems].

A series of experiments were designed to investigate copper sorption and desorption by loess in hyper-concentrated sediment systems. The results demonstrate that loess had large copper sorption capacity because of its specific adsorption and precipitation of carbonate and hydroxide. Copper sorption decreased with increasing ionic strength of solution, but the effects of varying cationic charge of supporting electrolyte were still detected. Less than 4% of copper was desorbed in the neutral saline solution, and increased with increasing ionic strength of solution. The pH was the most dominant factor on copper desorption. More than 70% of copper can be desorbed in the acid solution, and copper desorption increased with the decrease of solution pH. When pH of solid-liquid system was fixed, copper desorption from equivalent loess increased with the increase of solution volume, and copper desorption in the same sediment concentration increased with the adsorptive capacity.

Adsorption↗

PubMed2002

Structural insights into group II intron catalysis and branch-site selection.

Group II self-splicing introns catalyze autoexcision from precursor RNA transcripts by a mechanism strikingly similar to that of the spliceosome, an RNA-protein assembly responsible for splicing together the protein-coding parts of most eukaryotic pre-mRNAs. Splicing in both cases initiates via nucleophilic attack at the 5' splice site by the 2' OH of a conserved intron adenosine residue, creating a branched (lariat) intermediate. Here, we describe the crystal structure at 3.0 A resolution of a 70-nucleotide RNA containing the catalytically essential domains 5 and 6 of the yeast ai5gamma group II self-splicing intron, revealing an unexpected two-nucleotide bulged structure around the branch-point adenosine in domain 6.

Adenosine↗

PubMed2002

Enantioselective synthesis of no-carrier-added (NCA) 6-[18F]fluoro-L-DOPA.

The application of a chiral phase-transfer-catalyst (PTC) in the synthesis of N.C.A. 6-[18F]fluoro-L-DOPA has been recently developed. The 6-trimethylammoniumveratraldehyde triflate precursor and PTC (O-allyl-N-(9)-anthracenylcinchonidinium bromide) were synthesized and successful synthesis route was developed for the preparation of 6-[18F]fluoro-L-DOPA with high radiochemical yields (4-9%, decay uncorrected) and short synthesis time (80min). The radiochemical purity was over 99% and no D-isomer was detected by HPLC analysis using a chiral mobile phase.

Journal Article↗

PubMed2002

[The effects of non-pharmacotherapy in decreasing the levels of serum lipid in patients with hyperlipidemia].

OBJECTIVE: To develop a non-pharmacotherapy program for patients with hyperlipidemia and assess its effectiveness. METHODS: A cluster control trial was used. The experimental group was given non-pharmacotherapy for hyperlipidemia once a week for 6 weeks; the content of non-pharmacotherapy included the basic knowledge about hyperlipidemia, a guide of changing unhealthy diet and life-style. Patients were followed for once every two weeks in the department of out-patient. The control group received general care conducted by university clinicians, without the non-pharmacotherapy program. A self-completion questionnaire on hyperlipidemia-related knowledge level, questionnaires on diet and exercise, body weight, body height and the serum TG, TC were measured at entry point and at the end of 6 month. RESULTS: One hundred and fifty-four patients in experimental group and 150 patients in control group completed the study. The non-pharmacotherapy group showed a significant increase of knowledge on hyperlipidemia in the experimental group comparing with the control group: the mean (sd) score of hyperlipidemia-related knowledge were 22.5 (4.8), 17.4 (4.2) (95% CI: 4.1, 6.1). The diet score and the proportion of regular physical activity had increased 27.20%, 21.78% respectively in experimental group. The mean (sd) of serum TG, TC and body mass index (BMI) for experimental group [2.0 (0.9) mmol/L, 5.4 (0.9) mmol/L, 23.4 (1.9)] lowered significantly comparing to those for control group [2.4 (0.9) mmol/L, 5.9 (1.0) mmol/L, 24.2 (3.0)]. CONCLUSION: Non-pharmacotherapy seemed to be an important intervention for the patients with hyperlipidemia. If same patients with hyperlipidemia failed to respond to non-pharmacotherapy, it is necessary to use pharmacotherapy. However, non-pharmacotherapy should be viewed as basic therapy.

Adult↗

PubMed2002

[Repopulation with exogenous mitochondria in the cell].

To create human mitochondrial DNA (mtDNA)-transferred cells as cell model of mitochondria defects-related diseases, platelet of normal young and old subjects were isolated as donor of mtDNA, then fused with mtDNA-depleted cells (rho0 cells) under induction of PEG1500. Auxtrophy test, cytochrome c oxidase activity assay and PCR amplification of mtDNA were done to confirm the transferring of mtDNA. Cell clones were visible in the medium 10 to 15 days after fusion, which grew well in medium lacking uridine, had positive COX activity and contained objective fragment of mtDNA by PCR, opposite to rho0 cells. Transferring of mtDNA to rho0 cells was identified, and mtDNA-transferred cell models were successfully created.

Adult↗

PubMed2001

Coexpression of DNA Fragmentation Factor Subunits in E.coli by Two Incompatible Plasmids.

The human DNA fragmentation factor (DFF) is a heterodimer of 40 kD (DFF40/CAD) and 45 kD(DFF45/ICAD) subunits. Apoptotic DNA fragmentation and chromatin condensation are mediated by the caspase-activated DFF40 nuclease, which is inhibited by a chaperone-like subunit DFF45. In this work, the coding regions of human DFF45 and DFF40 mRNAs were amplified from total RNA of HeLa cells by RT-PCR. Two 1 kb DNA fragments were obtained and were cloned into a kanamycin-resistant bacterial expression vector, pET-28a( ), generating pET28a-DFF45 and pET28a-DFF40, which were then used to transform E.coli BL21(DE3), respectively. After induction with IPTG, DFF45 and DFF40 were expressed effectively, accounting for about 56% and 22% of total bacterial proteins, respectively. Since successful expression of properly folded DFF40 requires coexpression with DFF45, the full-length DFF45 cDNA was inserted into an ampicillin resistant expression vector, pET-21a( ), and the recombinant plasmid was designated pET21a-DFF45. Under screening pressure by ampicillin and kanamycin simultaneously, E.coli BL21(DE3) was cotransformed with pET21a-DFF45 and pET28a-DFF40. Upon induction with IPTG, DFF45 and DFF40 were coexpressed efficiently and the desired products comprised about 30% and 17% of total cell proteins, respectively. To further study the stability of the two incompatible plasmids'coexistance in E.coli, the cotransformant was cultured in liquid medium containing ampicillin and kanamycin for 14 h, and more than 75% of the cells were found to be resistant to the two antibiotics, that is, they carried both pET21a-DFF45 and pET28a-DFF40. Thus, a novel method of coexpressing different proteins using two incompatible plasmids was developed.

Journal Article↗

PubMed2001

Recombinant Human DFF45 Inhibits Apoptosis-specific Endonuclease in a Cell-free System of Xenopus Egg Extracts.

The human DNA fragmentation factor (DFF) is a heterodimer of 40 kD and 45 kD subunits. The 40 kD subunit (DFF40) has an intrinsic DNase activity responsible for the genomic DNA degradation into nucleosomal fragments during apoptosis. As an inhibitor for DFF40, the 45 kD subunit (DFF45) complexes with DFF40, inhibiting DNase activity until certain apoptosis signals are received. In cells undergoing apoptosis, the cleavage of DFF45 by activated caspase-3 frees DFF40from the complex and initiates the apoptosis-specific DNA fragmentation. In this report, the coding region of human DFF45 gene was amplified from the total RNA of HeLa cells by RT-PCR. The resulting 1 kb DNA fragment was cloned into the bacterial expression vector pET-28a(+) with a 6xhistidine tag fused to the N-terminus of DFF45, generating plasmid pET28a-DFF45, which was then used to transform E.coli BL21(DE3). Induced by IPTG, the recombinant DFF45 was expressed efficiently with a yield of 56.6% of total bacterial proteins. The product was purified to homogeneity through a nickel affinity column, followed by heat treatment, and approximately 4--6 mg of DFF was purified from 100 ml culture. Purified recombinant human DFF45, added into the apoptotic cell-free system of Xenopus egg extracts, could effectively inhibit both the digestion of lambdaDNA and the degradation of chromosomal DNA into nucleosomal fragments in the nuclei of chicken red blood cells. Our results demonstrated the existence of an apoptosis-specific endonuclease in this cell-free system, the activity of which could be inhibited by recombinant human DFF45.

Journal Article↗