[Preliminary clinical study on drug-induced liver lesions in 104 patients].
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Adolescent↗
Biomedical subjects
Hui Yang
Publications and source records attributed to Hui Yang.
[Landscape pattern variation of forest resources in typical forest zone of Changbai Mountains].
Based on GIS and RS data of 1985 and 1999 and the ground information from Lushuihe Forest Bureau, this paper studied the forest landscape pattern and its changes in typical forest zone of Changbai Mountains. According to the standard variance of patch areas in 1985 and 1999, the patch area distribution of mature conifer forest, mature broad-leaved forest, middle-aged conifer forest, and middle-aged broad-leaved forest was less symmetrical, showing that these land covers had landscape diversity and species diversity. According to landscape similarity index, the mature conifer forest, mature broad-leaved forest, middle-aged conifer forest and middle-aged broad-leaved forest, which were relatively stable than other land covers, made the majority of the landscape in the study area. According to patch density, the porosity of wetland was high in 1985 and 1999, indicating that wetland had little homogenization and formed more mosaics. The fragmentation extent of farming land, due to multiple cultivating types, azimuths and shapes, was high in both phases. Attributing greatly to anthropogenic factors, the fragmentation extent of wetland was high all along. In brief, the forest landscape pattern was changed greatly in the studied phases, and human activities affected heavily on it.
Biodiversity↗
[Macrolide-resistant Streptococcus pneumoniae in the pediatric population in Beijing].
OBJECTIVE: To analyze the mechanisms of macrolide resistance in Streptococcus pneumoniae from children in Beijing. METHODS: The MICs of penicillin and erythromycin were determined by the E-test methods for 200 Streptococcus pneumoniae isolates collected from 2002 to 2003 at Beijing Children's Hospital. MICs of azithrhomycin, clarithromycin, acetylspiramycin and clindamycin for 147 erythromycin-resistant isolates were detected by the agar dilution methods. For phenotyping, macrolide resistance induction tests were used in erythromycin-resistant isolates. PCR was used to determine the presence of the erythromycin-resistant genes. RESULTS: Of 200 Streptococcus pneumoniae isolates, 89.5% were resistant to erythromycin. In 147 erythromycin-resistant isolates, resistance rates were as follows: azithromycin, 100%; clarithromycin, 100%; acetylspiramycin, 95.2%; and clindamycin, 95.9%. The most common macrolide resistance phenotype was the cMIS phenotype (95.9%), 1.4% had the iMLS phenotype and 2.7% the M phenotype. Erythromycin-resistant isolates were characterized for the underlying resistance genotype, with 79.6% having the ermB genotypes, 17.7% having both ermB and mefA, 2.7% having the mefA, and none having neither ermB nor mefA genotypes. CONCLUSIONS: The rates of carriage of macrolide-resistant Streptococcus pneumoniae by children were high in Beijing during 2002 - 2003. cMLS was the most prevalent phenotype among erythromycin-resistant Streptococcus pneumoniae isolates, and ribosomal modification (ermB gene coded) was the main resistance mechanism against macrolides in Beijing region.
Anti-Bacterial Agents↗
[Studies of the expression, purification, renaturation and biologic activity of an anti-CEA immunotoxin].
A recombinant immunotoxin named CEA/PE38/KDEL was constructed, which was composed of anti-CEA single-chain Fv and the truncated and modified form of Pseudomonas exotoxin (PE38/KDEL). The CEA/PE38/KDEL immunotoxin was expressed in the E. coli strain BL21 (DE3)-star as inclusion bodies. The denatured inclusion bodies were purified with Ni-NTA chelate agarose, then the constant gradient dialysis was used to perform the refolding of the CEA/PE38/KDEL immunotoxin. Results of FACS and MTT assay indicate that the refolded immunotoxins keep potent and specific cytotoxicity to tumor cells bearing CEA antigens.
ADP Ribose Transferases↗
[Effects of CD/5-FC suicide gene therapy system on human malignant glioma cells in vitro].
OBJECTIVE: To investigate the killing effects of cytosine deaminase/5-fluorocytosine (CD/5-FC) suicide gene therapy system on human malignant glioma cells in vitro. METHODS: The pCMVCD plasmid was transfected into the U251 human malignant glioma cells using Lipofectamine 2000-mediated method. Resistant clones (named U251/CD cells) were isolated by screening with G418 presence. U251/CD cells were incubated with 5-FC in different concentrations to determine the number of viability cells (or cytotoxicity assay), and measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The concentrations of 5-fluorouracil (5-FU) in the media were measured by the high-performance liquid chromatography (HPLC) analysis. RESULTS: The untreated U251 cells were insensitive to 5-FC, with the IC50 about 6 500 micromol/L. After the transfection, the IC50 was dramatically reduced to about 10 micromol/L. Therefore, gene transfection made G418-resistant clones (U251/CD cells) highly sensitive to 5-FC. HPLC analysis showed that 5-FU was detected in U251/CD cell medium. CONCLUSION: The killing effects of U251 cells modified by CD gene were induced by 5-FC, and the CD/5-FC system was feasible to treat glioma.
Brain Neoplasms↗
Digital shearing method for three-dimensional data extraction in holographic particle image velocimetry.
We report a new digital shearing method for extracting the three-dimensional displacement vector data from double-exposure holograms. With this method we can manipulate both the phase and the amplitude of the recorded signal, which, like optical correlation analysis, is inherently immune to imaging aberration. However, digital shearing is not a direct digital implementation of optical correlation, and a considerable saving in computation time results. We demonstrate the power of the method by MATLAB simulation and discuss its performance with reference to optical analysis.
Journal Article↗
[Expression and assessment of double genes of tyrosine hydroxylase gene and aromatic L-amino acid decarboxylase gene in vitro].
The characteristic pathological changes of Parkinson s disease (PD) include a severe loss of dopamine neurons in the substantia nigra and a severe decrease in dopamine in the striatum. Since the expression of tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC) in the biosynthetic pathway for dopamine are low, a promising approach to the gene therapy of PD is to augment the gene expression of the enzymes in the biosynthetic pathway for dopamine. In the present study, human TH and AADC genes were reconstructed into retrovirous vectors pLHCX and pLNCX(2) respectively. Then pLHCX/TH and pLNCX(2)/AADC were transfected into packaging cell line PA317 with liposome. PA317/TH and PA317/AADC were selected by different antibiotics. Gene expression was examined by methods of immunohistochemistry and in situ hybridization. The catalytic activity of two cloned gene enzymes was assessed in vitro by HPLC-EC. Immunocytochemical staining showed that TH and AADC were expressed efficiently in vitro. Both TH and AADC mRNA were transcripted in PA317 cell lines by using in situ hybridazation. HPLC-EC experiments revealed that the transfected cells produced a significantly higher level of dopamine and L-dopa than the untransfected cells. The two genetically modified cells could improve the production of L-dopa and dopamine in response to suitable substrate. The present results suggest that not only recombinant TH and AADC genes are successfully expressed in vitro, but also the enzymes have respective functional activities. These results have set up a way for in vivo gene therapy of PD with TH and AADC genes.
Aromatic-L-Amino-Acid Decarboxylases↗
Effects of bile salts on percolation and size of AOT reversed micelles.
The effects of two trihydroxy bile salts, sodium taurocholate (NaTC) and 3-[(3-cholamidylpropyl)dimethylammonio]-1-propane sulfonate (CHAPS), on the size, shape and percolation temperature of reversed micelles formed by sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in isooctane were studied. The percolation temperature of the reversed micelles decreased upon inclusion of bile salts, indicating increased water uptake. Dynamic light scattering (DLS) measurements showed consistent enlargement of reversed micelles upon addition of the bile salts; the hydrodynamic radius increased sixfold in the presence of 10 mM CHAPS and doubled in the presence of 5 mM NaTC. Inclusion of the enzyme yeast alcohol dehydrogenase (YADH) increased the percolation temperature and distorted the spherical structure of the AOT reversed micelles. The spherical structure was restored upon addition of bile salt. These results may help to explain the increase in activity of YADH in AOT reversed micelles upon addition of bile salts.
Journal Article↗
Adaptive diversification of bitter taste receptor genes in Mammalian evolution.
The diversity and evolution of bitter taste perception in mammals is not well understood. Recent discoveries of bitter taste receptor (T2R) genes provide an opportunity for a genetic approach to this question. We here report the identification of 10 and 30 putative T2R genes from the draft human and mouse genome sequences, respectively, in addition to the 23 and 6 previously known T2R genes from the two species. A phylogenetic analysis of the T2R genes suggests that they can be classified into three main groups, which are designated A, B, and C. Interestingly, while the one-to-one gene orthology between the human and mouse is common to group B and C genes, group A genes show a pattern of species- or lineage-specific duplication. It is possible that group B and C genes are necessary for detecting bitter tastants common to both humans and mice, whereas group A genes are used for species-specific bitter tastants. The analysis also reveals that phylogenetically closely related T2R genes are close in their chromosomal locations, demonstrating tandem gene duplication as the primary source of new T2Rs. For closely related paralogous genes, a rate of nonsynonymous nucleotide substitution significantly higher than the rate of synonymous substitution was observed in the extracellular regions of T2Rs, which are presumably involved in tastant-binding. This suggests the role of positive selection in the diversification of newly duplicated T2R genes. Because many natural poisonous substances are bitter, we conjecture that the mammalian T2R genes are under diversifying selection for the ability to recognize a diverse array of poisons that the organisms may encounter in exploring new habitats and diets.
Amino Acid Sequence↗
Bioactive novel polyphenols from the fruit of Manilkara zapota (Sapodilla).
Activity-guided fractionation of a methanol extract from the fruit of Manilkara zapota cv. Tikal resulted in the isolation of two new antioxidants, methyl 4-O-galloylchlorogenate (1) and 4-O-galloylchlorogenic acid (2), along with eight known polyphenolic antioxidants, namely, methyl chlorogenate (3), dihydromyricetin (4), quercitrin (5), myricitrin (6), (+)-catechin (7), (-)-epicatechin (8), (+)-gallocatechin (9), and gallic acid (10). Of the 10 polyphenols, 1 showed the highest antioxidant activity (IC(50) = 12.9 microM) in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay and displayed cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC(50) values of 190 and 160 microM, respectively. Compound 2 showed high antioxidant activity (IC(50) = 23.5 microM) in the DPPH free-radical assay and displayed cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC(50) values of 154 and 134 microM, respectively.
Antioxidants↗
New bioactive polyphenols from Theobroma grandiflorum ("cupuaçu").
Activity-guided fractionation of Theobroma grandiflorum ("cupuaçu") seeds resulted in the identification of two new sulfated flavonoid glycosides, theograndins I (1) and II (2). In addition, nine known flavonoid antioxidants, (+)-catechin, (-)-epicatechin, isoscutellarein 8-O-beta-d-glucuronide, hypolaetin 8-O-beta-d-glucuronide, quercetin 3-O-beta-d-glucuronide, quercetin 3-O-beta-d-glucuronide 6' '-methyl ester, quercetin, kaempferol, and isoscutellarein 8-O-beta-d-glucuronide 6' '-methyl ester, were identified. Theograndin II (2) displayed antioxidant activity (IC(50) = 120.2 microM) in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay, as well as weak cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC(50) values of 143 and 125 microM, respectively. While 1 was less active as an antioxidant than 2, the known compounds were more potent in the DPPH assay (IC(50) range 39.7-89.7 microM).
Antineoplastic Agents, Phytogenic↗
Apoptosis and activation of Erkl/2 and Akt in astrocytes postischemia.
We have shown previously that in vitro ischemia could induce apoptosis in primary culture of astrocytes. In this paper we demonstrate that astrocytes in culture could undergo apoptosis during in vitro incubation postischemia. We also measured the changes of phosphorylated Erk1/2 (p-Erk1/2) and phosphorylated Akt (p-Akt) in order to determine whether these two pathways play a role in apoptosis. After 4 h in vitro ischemic incubation of cultured astrocytes, a limited amount of nuclear condensation was demonstrated by Hoechst 33342 staining. When ischemic incubation was halted and the cultures transferred to standard normoxic incubation (postischemia) conditions, DNA fragmentation and apoptosis were demonstrated by TUNEL and DNA laddering analysis. TUNEL-positive astrocytes began to appear at 6 h postischemia and increased in number from 12 h postischemia. Western blot analysis showed that both p-Erk1/2 and p-Akt were elevated in astrocytes subjected to 4 h of ischemia. Elevated p-Erk1/2 levels were sustained during the postischemia incubation for 12 h and decreased significantly afterward, but did not return to the levels in the control cultures that did not experience ischemic insult. In contrast, the p-Akt level continued to increase at 6 and 12 h postischemia before declining significantly. The changes in p-Erk1/2 and p-Akt correlated well with the appearance of apoptotic astrocytes in the culture.
Animals↗
Protective effect of nerve growth factor on neurons after traumatic brain injury.
The protective effect of nerve growth factor (NGF) on neurons after traumatic brain injury (TBI) was investigated. A brain trauma model of fluid-percussion in rats was established, and 7s NGF was infused continuously in its cerebral ventricle. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), and [Ca2+]i overloading in brain tissues was observed after giving exogenous NGF postinjury. We found that the activity of SOD, GSH-Px, and CAT was markedly higher in NGF-treated group than in the simple trauma group (P < 0.01). Although the level of [Ca2+]i in the NGF-treated group increased, the value was significantly lower than that in the simple trauma and control groups (P < 0.01). These findings suggest that exogenous NGF can (a) increase the activity of the major antioxidant enzymes in brain tissues and attenuate the injuries to neurons induced by oxygen-free radicals, (b) reduce the severe overload of [Ca2+]i and stabilize its homeostasis, and (c) provide clear protective effects on neurons after traumatic brain injury.
Animals↗
[Proteomics analysis and biochemical activity detection on facial nerve regeneration fluid].
OBJECTIVE: To explore the protein components and the biological neutrional activity upon motor neuron, so that take a general, basic study on the nerve regeneration microenvironment which be important to facial nerve regeneration. METHOD: The animal model of rabbit facial regeneration microenvironment is established. Advanced technology of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was used to study on the structural proteins in the regeneration fluid, as well as the motor neuron culture was used to test the biological activity in it. RESULT: 850 +/- 78 protein spots were detected in the regeneration fluid. The body area, neurite length and OD value of experimental group are higher than that of control group. CONCLUSION: We got the protein image of facial nerve regeneration fluid by 2-D PAGE, and proved that many kinds and number of proteins in the regeneration fluid have neutrional activity on motor neuron.
Animals↗
Effects of CD/5-FC suicide gene therapy system on human malignant glioma cells in vitro.
The purpose of this paper is to investigate the antitumor effects of cytosine deaminase/5-fluorocytosine (CD/5-FC) suicide gene therapy system on human malignant glioma cells in vitro. The pCMVCD plasmid was constructed through the CD gene insertion in the multicloning site of eukaryotic expression vector pcDNA3.0, and confirmed by restriction endonuclease digestion/gene sequencing. The construct was subsequently transfected into the U251 human malignant glioma cells by using LipofectAMINE2000-mediated method. Resistant clones (named U251/CD cells) were isolated by screening with G418 presence. U251/CD cells were incubated with 5-FC in different concentrations to determine viability ratios (or cytotoxicity assay), measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The concentrations of 5-fluorouracil (5-FU) in the media were measured by high-performance liquid chromatography (HPLC) detector. Our results suggested that the untreated U251 cells were insensitive to 5-FC, with the IC(50) about 6500 micromol/L. After transfection, the IC(50) was dramatically reduced to about 10 micromol/L. Therefore, gene transfection made G418-resistant clones (U251/CD cells) be highly sensitive to 5-FC. HPLC analysis showed that 5-FU was detected in U251/CD cell medium. Study on U251 cells genetically modified by CD gene in vitro will play an essential role in glioma gene therapy in vivo. In conclusion, our results indicated that the CD/5-FC system was feasible to treat glioma.
Cell Death↗
[Relationship between the Fnu4HI site polymorphism of monoamine oxidase A gene and Parkinson's disease].
OBJECTIVE: To study the association between the polymorphism of human monoamine oxidase type A (MAO-A) gene and Parkinson's disease(PD). METHODS: Fnu4HI restriction fragment length polymorphism(RFLP) and PCR-RFLP were used to detect the mutation of MAO-A gene. The frequencies of alleles and genotypes at the MAO-A Fnu4HI locus on the X chromosome in different PD group were compared with those of the control group. RESULTS: It was found that the frequencies of G allele in the patients with PD and controls were 0.613 and 0.527 respectively, P=0.039 "the frequencies of TT genotype were 0.303 and 0.415(P=0.014), and the frequencies of GG genotype were 0.564 and 0.451 respectively(P=0.021). When the patients were divided into two groups by age-onset, significant difference in the allelic and genotypic frequencies was observed only between early-onset PD group and control group. And when the PD patients were grouped by sex, significant difference was observed only between male PD group and male control group (the frequencies of G allele being 0.669 and 0.500 respectively, P=0.005). CONCLUSION: This study revealed significant differences between PD group and control group in allelic and genotypic frequencies. The findings supported the hypothesis about an association between MAO-A gene and PD, suggesting that age at onset of PD and gender predisposition might be related to the putative association, and Fnu4HI SNP be a risk factor for PD.
Alleles↗
[Identification of bone marrow stromal cells and expression of tyrosine hydroxylase gene in them].
The study is to establish the method of isolation and identification of bone marrow stromal cells and to investigate the ability of bone marrow stromal cells to accept and express TH gene. Cells were isolated by a density gradient (lymphocytes separation) and identified by BrdU labeling and fluorescence-activated cell sorting (FACS) technology using CD11b, CD45 and CD90 antibodies. TH and lacZ gene were transfected to rBMSCs with an adeno-associated virus vector. The results showed that most tightly adherent cells in the primary culture were fibroblast-like and formed foci of two to four cells. The cells in the foci remained dormant for 2 to 4 days and then began to multiply rapidly. After several passages, the adherent cells became more uniformly spindle-shaped in appearance. BrdU, indicating that BMSCs replicate actively, labeled about 74.9% of cultured cells. Data from FACS showed that about 75% of isolated cells were CD90(+)/CD45(-)/CD11b(-), which is the marker of bone marrow stromal cells. The efficiency of TH gene transfection was about 75%. BMSCs could readily be genetically engineered and could be useful delivery targets of gene therapy for Parkinson's disease.
Animals↗
[Using two-dimensional gel electrophoresis to analyze the regeneration microenvironment of facial nerve and its response to acupuncture].
OBJECTIVE: To investigate the distribution of proteins in the regeneration microenvironment of facial nerve and its response to acupuncture. METHODS: We created an animal model using rabbit to imitate the regeneration microenvironment of facial nerve and analyzed the proteins in the microenvironment through the two-dimensional gel electrophoresis. RESULTS: We found that most proteins in the regeneration fluid were under relative molecular mass 80 x 10(3) and in the range of pI 4-7. An average of 800 +/- 53 protein spots was found in the control group compared to the 850 +/- 78 spots in the acupuncture group. In the matching spots, more than ten proteins were different between the two groups. CONCLUSION: There is no evidence to show that acupuncture has a positive effect on the regeneration microenvironment of facial nerve.
Acupuncture↗