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Z Lei

Publications and source records attributed to Z Lei.

At least 19 recordsLinked to original sources
PubMed2006

Effects of nutrient addition on phenol biodegradation rate in biofilm reactors for hypersaline wastewater treatment.

Hypersaline wastewater, generated by many industrial activities, is difficult to treat through conventional biological processes. In this kind of hypersaline environment, complex nutrients are needed for the normal growth of many microorganisms. For this paper, the organisms were taken from a municipal wastewater treatment plant and acclimated to 15% salinity in a biofilm treatment process (Sequencing Batch Biofilm Reactor) during the treatment of phenol-containing synthetic wastewater. They are used to evaluate the effects of nutrient addition on the phenol biodegradation rate. Adding yeast extract, glucose, KCl and four mineral nutrients into the shaking flasks containing wastewater and cultivating organisms, revealed phosphate as the crucial nutrient stimulating phenol biodegradation at 15% salinity. The operation results of the sequencing batch biofilm reactor indicates that phosphate content increased up to five times the original level can increase the phenol removal rate by 150%. A 99% phenol removal efficiency could be achieved by shortening the reaction time in the biofilm reactor from 40 h to 16 h, compared with basic nutrients added. In this article we applied an applicable and effective shaking-culture method to determine nutrient requirements in biotreatment processes without stopping the running reactors.

Biodegradation, Environmental↗
PubMed2004

Therapeutic drug monitoring of tacrolimus in early stage after heart transplantation.

INTRODUCTION: Little is known about the pharmacokinetic (PK) profiles of tacrolimus (Tac) within the first week after heart transplantation (HT) in adults. Our objective was to investigate the PK profiles of Tac in early after HT. METHODS: Twenty-three adult HT patients received Tac as primary immunosuppression. Tac was administered orally at a starting dosage of 0.10 mg/kg/d. The Tac dosages were adjusted to a target range of 10 to 20 ng/mL during the first 1 month after HT. The PK profiles were analyzed immediately after the first dose (PK1; n = 14), at day 3 (PK2; n = 10), and at day 7 (PK3; n = 8) to assess the relationships between PK parameters and acute rejection rates. RESULTS: The correlation between Tac trough levels and Tac-AUCs were r = .95 PK1; r = .82, PK2; and r = .88, PK3. When AUC(0-12h) was controlled in the range from 150 to 300 ng x h/mL (10 to 20 ng/mL trough levels), 17 of 18 patients (94.4%) did not show evidence of significant rejection (72.2% grade 0, 16.7% 1A, and 5.5% grade 1B). One patient displayed a grade 2 biopsy score (5.5%). Mean AUC(0-12h) values of Tac were significantly lower among patients who experienced acute rejection than those who remained rejection-free (89 vs 217 ng x h/mL, P = .023). CONCLUSION: The initial trough levels are good indicators of systemic exposure. To reduce the risk of rejection and renal toxicity, the trough levels should be controlled in range from 10 to 20 ng/mL in early stage after HT.

Adolescent↗
PubMed2001

Reconstruction of SEA-B7.1 double signals on human hepatocellular carcinoma cells and analysis of its immunological effect.

Since transfection of established tumors with immunostimulatory genes, such as superantigens (SAg), a family of bacterial and viral proteins with strong immunostimulatory properties, can elicit antitumor immunity, direct transfection of tumors with genes of staphylococcal enterotoxin A (SEA) could probably set up a new way of immunological pathway. In our study, human hepatocellular carcinoma (HCC) cell lines stably transduced with SEA and B7.1/SEA fused genes, HHCCSEA and HHCCBS, were obtained by using the method of retroviral mediated gene transduction. The results showed that human HCC cells could express SEA gene. Although a tiny quantity of expression was detected, a robust immune response was promoted. The cytotoxicity of CTL on HHCCBS was the same as that on HHCCSEA. But the K(m) value of the reaction of the former was lower than that of HHCCSEA. Furthermore, the activity assay of T cells by ELISPOT demonstrated that HHCCBS could elicit more CTL activity than HHCCSEA and HHCCB7.1. It suggested that the affinity of T cells to HHCCBS was higher and the maxim velocity of reaction could be attained at an early stage of the reaction. Transduced HCC cells were also analyzed for HLA expression, and it was found that a majority of the cells expressed HLA-I molecules but no HLA-DR molecules. After blocking the HLA-I molecules by HLA-I mAb, the cytotoxicity of T lymphocytes dropped remarkably. The results suggested that SEA were mainly presented by HLA-I molecules, and that B7.1 and SEA could have synergistic action at the early stage of the reaction, but the relationship between them in the consequent process needs to be clarified.

Carcinoma, Hepatocellular↗
PubMed2001

Capillary electrochromatography for separation of peptides driven with electrophoretic mobility on monolithic column.

A mode of capillary electrochromatography for separation of ionic compounds driven by electrophoretic mobility on a neutrally hydrophobic monolithic column was developed. The monolithic column was prepared from the in situ copolymerization of lauryl methacrylate and ethylene dimethacrylate to form a C12 hydrophobic stationary phase. It was found that EOF in this hydrophobic monolithic column was very poor, even the pH value of mobile phase at 8.0. The peptides at acidic buffer were separated on the basis of their differences in electrophoretic mobility and hydrophobic interaction with the stationary phase; therefore, different separation selectivity can be obtained in CEC from that in capillary zone electrophoresis (CZE). Separation of peptides has been realized with high column efficiency (up to 150,000 plates/meter) and good reproducibility (migration time with RSD <0.5%), and all of the peptides, including some basic peptides, showed good peak symmetry. Effects of the mobile phase compositions on the retention of peptides at low pH have been investigated in a hydrophobic capillary monolithic column. The significant difference in selectivity of peptides in CZE and CEC has been observed. Some peptide isomers that cannot be separated by CZE have been successfully separated on the capillary monolithic column in this mode with the same buffer used.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2001

Hybrid characteristics of oligonucleotides consisting of isonucleoside 2',5'-anhydro-3'-deoxy-3'-(thymin-1-yl)-D-mannitol with different linkage modes.

Oligonucleotides consisting of the isonucleoside repeating unit 2',5'-anhydro-3'-deoxy-3'-(thymin-1-yl)-D-mannitol (4) were synthesized with the monomeric unit 4 incorporated into oligonucleotides as 1'-->4' linkage 4a (oligomer I) or 6'-->4' linkage 4b (oligomer II). The hybrid properties of the two oligonucleotides I and II with their complementary strands were investigated by thermal denaturation and CD spectra. Oligonucleotide I (4a) formed a stable duplex with d(A)(14) with a slightly reduced T(m) value of 36.6 degrees C, relative to 38.2 degrees C for the control duplex d(T)(14)/d(A)(14), but oligomer II (4b) failed to hybridize with a DNA complementary single strand. The spectrum of the duplex oligomer I/d(A)(14) showed a positive CD band at 217 nm and a negative CD band at 248 nm attributable to a B-like conformation. Molecular modeling showed that in the case of oligomer I: the C6' hydroxy group of each unit could be located in the groove area when hybridized to the DNA single strand, which might contribute additional hydrogen bonding to the stability of duplex formation.

Circular Dichroism↗
PubMed2001

Enantiomer separation by strong anion-exchange capillary electrochromatography with dynamically modified sulfated beta-cyclodextrin.

A novel mode of capillary electrochromatography (CEC) based on a dynamically modified stationary phase was presented for chiral separation. The capillary column was packed with strong anion-exchange (SAX) stationary phase packing; the sulfated beta-cyclodextrin (S-CD), which was added to the mobile phase, was dynamically adsorbed to the packing surface. Separation of enantiomers was achieved by their different abilities to form an inclusion complex with the adsorbed S-CD. The enantiomers of tryptophan, praziquantel, atropine, metoprolol, and verapamil were successfully separated in this system with a column efficiency of 36000-412000 plates/m. The resolution value obtained for atropine was as high as 11.23. The superiority of CEC with a dynamically modified stationary phase over that with a physically adsorbed stationary phase was demonstrated. The influence of ionic strength, S-CD concentration, and methanol content on separation was also studied.

Anions↗
PubMed2001

Separation of basic, acidic and neutral compounds by capillary electrochromatography using uncharged monolithic capillary columns modified with anionic and cationic surfactants.

A mode of capillary electrochromatography (CEC), based on the dynamical adsorption of surfactants on the uncharged monolithic stationary phases has been developed. The monolithic stationary phase, obtained by the in situ polymerization of butyl methacrylate with ethylene dimethacrylate, was dynamically modified with an ionic surfactant such as the long-chain quaternary ammonium salt of cetyltrimethylammonium bromide (CTAB) and long-chain sodium sulfate of sodium dodecyl sulfate (SDS). The ionic surfactant was adsorbed on the surface of polymeric monolith by hydrophobic interaction, and the ionic groups used to generate the electroosmotic flow (EOF). The electroosmotic mobility through these capillary columns increased with increasing the content of ionic surfactants in the mobile phase. In this way, the synthesis of the monolithic stationary phase with binary monomers can be controlled more easily than that with ternary monomers, one of which should be an ionic monomer to generate EOF. Furthermore, it is more convenient to change the direction and magnitude of EOF by changing the concentration of cationic or anionic surfactants in this system. An efficiency of monolithic capillary columns with more than 140000 plates per meter for neutral compounds has been obtained, and the relative standard deviations observed for to and retention factors of neutral solutes were about 0.22% and less than 0.56% for ten consecutive runs, respectively. Effects of mobile phase composition on the EOF of the column and the retention values of the neutral solutes were investigated. Simultaneous separation of basic, neutral and acidic compounds has been achieved.

Anions↗
PubMed2001

Dynamics and mechanism of ultraviolet photolysis of atrazine on soil surface.

The photolysis of atrazine in the soil surface under UV light and the factors affecting this has been studied. A rate constant of 0.09-0.17 min-1, photolytic depth of 0.1-0.3 mm and half-life of 4-8 min were determined. The results show that soil granularity, pH, humidity, organic content, humic acid and surface-active agents could affect the photolysis of atrazine in soil. GC-MS showed three photolytic products: 1-sec-butyl-4,4-diethyl-1-tetrazene, N2,N4-diethyl-6-methyl-1,3,5-triazine-2,4-diamine and 6-chloro-N2-propyl-1,3,5-triazine-2,4-diamine. The mechanism of the photolytic process is discussed.

Atrazine↗
PubMed2001

Use of methanolysis for the determination of total ellagic and gallic acid contents of wood and food products.

Anhydrous methanolic HCl has been found to be an excellent reagent for releasing ellagic acid and gallic acid (as methyl gallate) from biomass substrates. Optimization of both the reaction conditions and the gradient HPLC analysis has led to the development of a new protocol. The method provides ellagic acid yields significantly higher than those obtained previously, indicating total ellagic acid contents of several substrates have previously been underestimated.

Alcoholic Beverages↗
PubMed2001

[Genotype polymorphism and its implications of mannose-binding protein allele in 5 Chinese nationalities].

OBJECTIVE: To detect the genotypes and sequences of the exon 1 of human mannose-binding protein (MBP) allele in 5 Chinese nationalities. METHODS: The genotypes of MBP gene of 5 Chinese nationalities were detected by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). The exon 1 of the MBP gene of 22 Chinese Hans was analyzed by using ABI 310 genetic analyzer. RESULTS: The DNA sequences of exon 1 of Chinese MBP gene were acquired. The allele frequencies of the codon 54 of the MBP gene (MBP-54) of 5 Chinese nationalities were 0.181(Hans), 0.128(Uygurs), 0.181(Mongols), 0.179(Tibetans) and 0.181(Yis). The allele distribution for MBP-54 mutation of 5 Chinese nationalities was in good agreement with Hardy-Weinberg equilibrium. Compared with the Hans, Uygurs had a lower MBP-54 mutation rate. There were no differences in the allele frequencies between the chronic hepatitis B patients and health controls in Chinese Hans. The mutations of the codons 52 and 57 were not detected in this study. CONCLUSION: A higher prevalence of MBP-54 mutation was found in 5 Chinese nationalities, MBP-54 mutation was not associated with the persistence of hepatitis B.

Adolescent↗
PubMed2001

[Multimedia environmental behavior of herbicide atrazine].

In the paper, taking the Baiyangdiang Lake area as a study field, on the basis of soil characterization, environmental monitoring, and studies of adsorption, biodegradation, hydrolysis and photolysis, the atrazine concentrations in soil, groundwater and corn plant during 30 years were predicted by multimedia environmental fugacity model.

Adsorption↗
PubMed2001

[Genotyping of HIV resistant alleles in indigenous Tibetan ethnic group of China: low frequency of CCR5triangle32 and high frequency of CCR2b-64I alleles].

OBJECTIVE: To investigate the allelic polymorphism of CCR5triangle32, CCR5m303, CCR2b-64I and SDF1-3'A in Tibetan population in Lasa area of China. METHODS: The genomic DNA samples from 330 Tibetan subjects' whole blood samples were purified by use of QIAgen Blood Kit and identified by PCR or PCR-RFLP analyses. RESULTS: The mutation frequencies of CCR5triangle32 and CCR5m303 alleles were lower than 0.15%, and those of CCR2 b-64I and SDF1-3'A alleles were 29.42% and 19.24% respectively in the study samples. The allelic polymorphisms of the four alleles of Tibetan population were similar to those of Chinese Han population. Genotype distribution of the four alleles was in accordance with Hardy-Weinberg equilibrium. The above results suggest that Tibetan population may be relatively susceptive to HIV-1. CONCLUSION: The Chinese Tibetan may have a lower frequency of CCR5triangle32 and a higher frequency of CCR2b-64I allele, compared with Caucasian.

Adolescent↗
PubMed2001

[Adenovirus-mediated transfer of human wild-type p53, GM-CSF, and B7-1 genes efficiently produces growth suppression and apoptosis of hepatocellular cells in vitro].

OBJECTIVE: To investigate the tumor suppressor activity of recombinant adenovirus vector expressing the human wild-type p53, GM-CSF, and B7-1 proteins (designated as BB-102) in human hepatocellular carcinoma cells (HCC) in vitro. METHODS: The wild-type p53 BEL-7402, mutant p53 HLE, and HuH-7 HCC cell lines were infected with BB-102 at MOI of 50 in vitro. Immunohistochemical assay was used to determine p53 expressed by BB-102. Tumor suppressor activity of the expressed p53 was identified by terminal deoxynucleotidy I transferase (TdT) assay in BB-102-infected HCC cell lines. RESULTS: p53 protein was found to express in a dose-dependent manner in BB-102-infected HCC cell lines. The proliferation of HCC cell lines were suppressed significantly at the average rates of 58.5%, 81.5%, and 71.1% for BEL-7402, HLE, and HuH-7 respectively from 4 to 10 days, accompanying inducing apoptosis in BB-102-infected HCC cell lines. CONCLUSIONS: Besides the expression of B7-1 and GM-CSF, BB-102 is able to express p53 protein in independent manner and exerts its anti-tumor activity, which suggests that BB-102 may be useful for gene therapy against HCC in vivo.

Adenoviridae↗
PubMed2001

Genotypes and polymorphisms of mutant CCR5-delta 32, CCR2-64I and SDF1-3' a HIV-1 resistance alleles in indigenous Han Chinese.

OBJECTIVE: To evaluate the frequencies and polymorphisms of CCR5-delta 32, CCR2-64I and SDF1-3' A alleles conferring resistance to HIV-1 infection in Chinese population from Han ethnic origin. METHODS: This cohort was comprised of 1251 subjects (915 men and 336 women) aged 15-80 years and none was HIV-1 positive. Genotyping of allelic CCR5-delta 32, CCR2-64I and SDF1-3' A variants was performed using PCR or PCR/RFLP assay, and further confirmed by direct DNA sequencing. RESULTS: Our finding shows that the delta 32 deletion mutation in the CCR5 gene does occur in this population and can be inherited in a Mendelian fashion in indigenous Han Chinese at a very low frequency of 0.00119 (n = 1254). The frequencies of mutant CCR2-64I and SDF1-3' A alleles were 0.20023 (n = 1251) and 0.2873 (n = 893), in this population, which are higher than those found in American Caucasians. Furthermore the polymorphisms of CCR2-64I and SDF1-3' A alleles in the Han Chinese population were different from those in American Caucasians. Statistical analysis showed that the genotype distribution of CCR5-delta 32, CCR2-64I and SDF1-3' A alleles was in equilibrium according to the Hardy-Weinberg equation. CONCLUSION: The CCR5-delta 32 mutation may not be a major resistant factor against HIV-1 infection in indigenous Han Chinese. The significance of higher frequencies of CCR2-641 and SDF1-3' A alleles (0.20023 and 0.2791) in the Han population remains to be clarified in HIV-1-positive carriers and AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed2001

[Influence of staphylococcal enterotoxin A on immunogenicity of hepatocellular carcinoma cells].

OBJECTIVE: To transduce the gene of staphylococcal enterotoxin A (SEA) into a HCC cell line HHCC and to make the cells to express the molecules of SEA for the purpose of improving the immunogenicity and inducing immune rejection of HCC. METHODS: Construct retroviral vector containing the gene of SEA and transduce it into HHCC cells. Then the integration, transcription and expression of recombinant were analyzed. At last cytotoxicity test of peripheral blood mixed lymphocytes was carried out. RESULTS: We obtained the retroviral vector pLXSN-SEA, transduced into HHCC cells and obtained the HCC cell line that expressed SEA toxin protein. The content of SEA in supernatant was at the level of pg. The cytotoxicity of HHCC transduced with SEA by T lymphocytes was 45.6%, which was higher than that of HHCC (20.7%). The Km value of T lymphocytes against HHCC transduced with SEA and without SEA was 5.18 x 10(4) and 2.92 x 10(5), separately. The difference had statistical significance. CONCLUSIONS: After transducing the SEA gene, although tiny quantity of expression is detected, the cytotoxicity assay proves that the expression of SEA lead to a robust immune response.

Carcinoma, Hepatocellular↗
PubMed2001

OxLDL upregulates growth-regulation oncogene alpha expression in human endothelial cells.

OBJECTIVE: To explore the effect of oxLDL on CXC chemokine growth-regulated oncogene alpha (GRO alpha) expression in human endothelial cells and the possible functional significance of the effect. METHODS: LDL was isolated by sequential ultracentrifugation and oxidized to oxLDL. Reverse transcription-polymerase chain reaction with GAPDH as internal standard was applied and CXC chemokine GRO alpha mRNA in endothelial ECV304 cells was examined. ELISA was used to determine GRO alpha protein expression on ECV304 cells surface and in the medium. With static cell adhesion assays, the physiological significance of elevated GRO alpha expression was tested. RESULTS: OxLDL, not LDL, treatment of ECV304 cells significantly induced the expression of GRO alpha mRNA that was not detectable in untreated cells. Induction of expression was first evident at 1 h, became maximal at 2 h, and was substantially decreased by 4 h. In a concentration- and time-dependent manner, oxLDL, and not LDL, induced a significant upregulation of GRO alpha surface expression in ECV304 cells that was at a barely detectable level in unstimulated ECV304 cells. GRO alpha protein in the medium did not change significantly. Exposure of ECV304 cells to 40 micrograms protein/ml oxLDL for 24 h resulted in a marked increase in the number of U937 cells bound to ECV304 cells and antibodies to GRO alpha inhibited adhesion. CONCLUSION: OxLDL functionally upregulated GRO alpha expression in endothelial cells.

Cell Adhesion↗
PubMed2000

Study on open tubular capillary affinity liquid chromatography.

A novel mode of affinity chromatography (AC) based on an open tubular capillary column (OTAC) is demonstrated. The OTAC column is prepared by immobilizing Cibacron blue F3GA onto the inner surface of a 50-microm-i.d. capillary column. The AC experiment is performed on a capillary electrophoresis instrument by using its pressure system as the driving force. Bovine serum albumin and lysozyme (Lys) are successfully separated with stepwise gradient elution. The relative standard deviation (RSD) for the elution time of the retained Lys is 0.08%, and good repeatability of its peak area and peak height with an RSD value lower than 2.12% for 10 consecutive runs is observed. The loading capacity and detection limit for the retained Lys are approximately 36 ng and 8.6 ng, respectively. It is also found that the amount of protein adsorbed is unaffected by the flow rate of the loading buffer, and OTAC can be used for the fast determination of biopolymers. Some of the advantages of OTAC over conventional modes of open tubular capillary liquid chromatography are that the detection sensitivity and loading capacity of a sample can be greatly improved, because the relatively large inner diameter of the capillary can be adopted and the whole capillary column can be used to adsorb the solute in OTAC.

Journal Article↗