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Biomedical subjects

Wei Chen

Publications and source records attributed to Wei Chen.

At least 379 records · Page 21Linked to original sources
PubMed2004

[Accumulation and translocation of lead in soil-crop system of green food production].

In this paper, the accumulation and translocation of lead in soil-crop ecosystems were studied through fertilization with chemical fertilizer, manure and bio-fertilizer. The results showed that the soil total Pb content was decreased with soil depth. It was 11.14 and 9.37 mg x kg(-1) in 0-15 and 15-30 cm after harvest, respectively. Rice root absorbed lead from soil, and transferred it to stem-leaf and grain. The Pb content in rice plant was root>stem and leaf>grain, which was increased with rice growth. The grains of 606-14 and Liao 294 contained 0. 008 and 0.007 mg x kg(-1) of Pb, respectively, which is under the standard of green food. Variance analysis indicated that the grain yield of different varieties had a significant variance, but no significant variance was found among different treatments. It could be summarized that manure or bio-fertilizer could be the substitute of chemical fertilizer in producing rice.

Absorption↗
PubMed2004

[Relationship of overexpression of angiogenesis factors and their receptors with invasive growth of keloid].

OBJECTIVE: To study the relationship between invasive growth and the angiogenesis factors and their receptors in keloid. METHODS: Biopsies from 17 keloid (Ke) were divided into atrophy group (Ke-A, n = 9), proliferating group (Ke-P, n = 13), infiltrating group (Ke-I, n = 9), normal skin around Ke (Ke-N, n = 10) and normal skin (NS, n = 10). The histology, immunohistochemistry and computerized imaging analysis were used for the study. The levels of basic fibroblast growth factor (bFGF) and its receptor-Flg, vascular endothelial growth factor (VEGF) and VEGF/KDR complex (11B5), and platelet derived growth factor (PDGF-A) and its receptor-PDGFR-alpha, and alpha-smooth muscle actin (alpha-SMA) were determined in specimens with immuneohistochemical staining. RESULTS: In all 5 groups, bFGF, Flg, VEGF, 11B5, PDGF-A, and PDGFR-alpha were all expressed in fibroblasts (Fb), monocyte-phagocytes, vascular endothelial cells, adventitial cells, epidermal (cells and epithelial cells in appendage. The intensities of staining ranked as follows: Ke-I > Ke-N approximately equal to Ke-P > Ke-A approximately equal to NS, Flg > hFGF approximately equal to PDGFR-alpha > PDGF-A approximately equal to 11B5 > VEGF (P < 0.05 to approximately 0.01). 11B5 and VEGF were expressed (intensively in alpha-SMA positive myofibroblasts only in Ke-I group. The histological observation showed hyperplasia of endothelial cells and obliteration of microvessels. CONCLUSION: The invasive growth of keloid may be related to the overexpression of angiogenesis factors and their receptors. The abnormal expression of 11B5 in myofibroblasts may be one of the important factors associated with tumor-like growth feature in the invasive parts sites of keloid. The results suggest that inhibition of these biological activities would be of significance in clinical therapy.

Adolescent↗
PubMed2004

[The effects of combined reverse Nance and TPA on reinforcement of anchorage].

PURPOSE: To evaluate the effects of combined reverse Nance and TPA on anchorage control. METHODS: 16 female adults with Class II division 1 malocclusion were treated with the combined mechanism of reverse Nance and TPA in an attempt to reinforce molar anchorage. Cephalometric analysis and model measurements were conducted for the assessment of anchorage control. RESULTS: The mesial movement of the upper first molars were minimized within 1/5 extracted space, parameters such as UMVD, MP-FH, ANS-Me remained unchanged, indicating the molar anchorage was controlled effectively. CONCLUSION: The modified combination of reverse Nance and TPA might be effective in anchorage forcement.

Adolescent↗
PubMed2004

[Gene expression of extracellular-signal regulated protein kinase 5 and their MAPKK in fetal skin hypertrophic scars].

OBJECTIVE: To explore the change of gene expression of extracellular-signal regulated protein kinase 5 (ERK5) and its upstream signaling molecule (MEK5) in fetal skin of differentially developmental stages and hypertrophic scars. METHODS: After morphological characteristics of skin of different developmental stages and hypertrophic scars were detected with pathological methods, gene expression of ERK5 and MEK5 was examined with reverse transcription-polymerase chain reaction analysis (RT-PCR). RESULTS: In early gestational fetal skin, genes of ERK5 and MEK5 were strongly expressed, while in late gestational skin and children skin, the expression of ERK5 and MEK5 was apparently decreased (P < 0.05). In normal skin, the level of gene expression of ERK5 was lower. In proliferative hypertrophic scars, mRNA content of this gene was apparently increased. In mature scars, the content of this gene transcript was 3.2 times the normal skin. In contrast, the levels of MEK5 transcript in normal skin and hypertrophic scars of various phases showed no substantial changes (P > 0.05). CONCLUSION: ERKS medicating signaling pathway might be involved in regulating cutaneous development at the embryonic stage and determining cutaneous structure ad function. The increase of gene transcription of ERK5 and MEK5 in younger fetal skin might be a reason for rapid proliferation of the skin cells and scraless healing of skin. The activation of ERK5 gene expression in hypertrophic scars versus normal skin might be one of the mechanisms controlling the formation of hypertrophic scars, in which the role of MEK5 needed to be further studied.

Child↗
PubMed2004

[Brain-derived neurotrophin factor inhibits steroid biosynthesis by human granulosa-lutein cells].

OBJECTIVE: To study the effect of brain-derived neurotrophin factor (BDNF) on the synthesis of estradiol and progesterone in human granulose-lutein cells (HGLCs) and the expression of steroidogenic acute regulatory factor (STAR) mRNA. METHODS: HGLCs were obtained from infertile women undergoing ovulation induction for fertilization-embryo transfer (IVF-ET) for male or tubal factors. HGLCs were cultured in serum-free media 199 for 24 h and treated by BDNF at 25, 50 and 100 ng/ml. Radio immunoassay (RIA) was used to examine the concentration of estradiol and progesterone, and reverse transcriptional PCR (RT-PCR) employed to detect the expression of STAR mRNA after treatment with BDNF at the concentrations of 25, 50 and 100 ng/ml. RESULTS: BDNF significantly inhibited the production of progesterone (P(4)) in the culture media of HGLCs in a dose-dependent manner. BDNF did not change the level of 17beta-estradiol (E(2)), but decreased the expression of STAR mRNA dose-dependently. CONCLUSIONS: BDNF can inhibit the synthesis of P(4) in HGLCs and regulate ovarian steroidogenesis. BDNF may inhibit HGLCs from producing P(4) by decreasing the transcription level of STAR gene in human ovary, and plays an important role in luteal regression.

Adult↗
PubMed2004

Effect of different iodine intake on schoolchildren's thyroid diseases and intelligence in rural areas.

BACKGROUND: Reports are increasingly appearing on the side effects caused by excessive iodine intake. Our objective was to find out whether iodine excess would impair the thyroid function and intelligence of schoolchildren in rural areas of China. METHODS: A comparative epidemiological study was made on thyroid function and intelligence of the schoolchildren in the areas of low, moderate or excessive intake of iodine. In the area of low intake of iodine (Panshan, Liaoning province, median urinary iodine (MUI) was 99 microg/L), of moderate intake of iodine (Zhangwu, Liaoning Province, MUI was 338 microg/L) and of excessive intake of iodine (Huanghua, Hebei Province, MUI was 631 microg/L). The numbers of schoolchildren from each area selected to take part in a Chinese version of Raven's Test were 190, 236 and 313, respectively, and then 116, 110 and 112 of them were tested for thyroid function, thyroid autoantibody (TAA) and urinary iodine (UI). RESULTS: There were no significant differences in the incidences of overt hyperthyroidism, subclinical hyperthyroidism and overt hypothyroidism in Panshan, Zhangwu and Huanghua. But significant differences were found in the incidences of subclinical hypothyroidism (P = 0.001) in these three areas. The incidences of subclinical hypothyroidism in Huanghua and Zhangwu were 4.76 and 3.37 times higher than that in Panshan. TAA were negative in all the schoolchildren with subclinical hypothyroidism except for one. No significant difference was found among the rates of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) in these three areas. Mean serum thyroglobulin (TG) value of Huanghua was markedly higher than those of the other two (P = 0.02). Mean serum TG value of Zhangwu was higher than that of Panshan but the difference was not significant. Mean IQ value of the schoolchildren in Huanghua was markedly higher than that for Zhangwu (P = 0.001). Mean IQ value of the schoolchildren in Panshan was lower than that of Huanghua and higher than that of Zhangwu but, again, the differences were not significant. CONCLUSIONS: The increase of iodine intake may increase the risk for schoolchildren of subclinical hypothyroidism. In the area of iodine excess, most of the subclinical hypothyroidism cases are not of autoimmune origin. No obvious effect of excess iodine was found on mental development of schoolchildren.

Child↗
PubMed2004

[Dynamical examination of auditory event-related potentials P300 and sympathetic skin response in people with insomia of Sweet Dream Capsule therapy].

OBJECTIVE: To observe the change of auditory event-related potentials (P300) and sympathetic skin response (SSR) in people with insomia of Sweet Dream Capsule therapy. METHODS: 30 patients meeting criteria for primary insomnia and 30 healthy volunteers with age matching controls were selected for the study. P300 and SSR were measured before treatment of Sweet Dream Capsule and at week 4 , 8 of the therapeutic course. That the change of P300 and SSR before and after treatment and their relations with PSQI were studied. RESULT: Compared with those of normal controls, both P300 latency and SSR latency were prolonged while amplitude was decreased in patients with insomnia (P < 0.01). P300 amplitude was increased significantly at central (Cz) electrode sites only at week 8 when compared with amplitude before treatment (P < 0.05). With improvement of symptom and PSQI scores, latency and amplitude of SSR were improved at week 4 and week 8 (P < 0.05 and P < 0.01) . CONCLUSION: P300 has a some improvement in people with insomia of Sweet Dream Capsule therapy while SSR im proves significantly, and PSQI scores are ameliorated too.

Adult↗
PubMed2004

[Effect of clozapine and risperidone on serum cytokine levels in patients with first-episode paranoid schizophrenia].

OBJECTIVE: To study the effects of clozapine and risperidone on serum cytokine levels in patients with first-episode paranoid schizophrenia, and explore the role of the cytokines in the psychopathological basis of the illness. METHOD: Fifty-eight patients with first-episode paranoid schizophrenia were treated with either clozapine or risperidone, and before and at the end of the 4th, 8th weeks and 6th months after the medication respectively, the serum levels of interleukin (IL)-6, 2, 18,and tumor necrosis factor (TNF)alpha were measured with enzyme-linked immunosorbent assay (ELISA). The Positive and Negative Syndrome Scale (PANSS) was used to evaluate the psychotic symptoms. RESULT: In patients treated with risperidone, the levels of serum IL-6 and IL-2 after 4 weeks, TNFalpha after 8 weeks, and IL-18 after 6 months were all significantly lowered in comparison with the pretreatment levels (P<0.01 or 0.05). In clozapine group, the levels of IL-2 after 4 weeks and IL-6 and IL-18 after 6 months were lowered significantly (P<0.01 or 0.05). Before the medication, serum IL-6 level was positively correlated with Positive Syndrome scores (r=0.386, P<0.01), IL-2 with the total score and Positive Syndrome scores (r=0.338, 0.305; P<0.01, 0.05), and TNFalpha with the total score (r=0.283, P<0.05). The changes of IL-2 and IL-6 after 8 weeks was positively correlated with the change of Positive Syndrome scores (r=0.268, 0.375; P<0.05, 0.01). Six months after the medication, the change in IL-6 and TNFalpha levels was positively correlated with the change of total score (r=0.365, 0.362; P<0.05). Before treatment, IL-6 was positively correlated with IL-2 levels (r=0.356, P<0.01), and TNFalpha with IL-18 levels (r=0.291, P<0.05). TNFalpha was positively correlated with IL-6 levels (r=0.332, P<0.01) 8 weeks after the medication. The changes in IL-6 was positively correlated with the those in IL-2 levels 6 months after the medication (r=0.391, P< 0.05). CONCLUSION: Clozapine and risperidone have similar immunosuppression actions and may affect serum IL-6 levels in patients with paranoid schizophrenia, in the psychopathology of which the cytokines play their roles of various importance.

Adolescent↗
PubMed2004

[Inhibitory effect of sinomenine on expression of cyclooxygenase-2 in lipopolysaccharide-induced PC-12 cells].

OBJECTIVE: To study the effects of sinomenine (Sin) on cell proliferation, intracellular expression of cyclooxygenase-2 (COX-2), and production of PGE2 in lipopolysaccharide-induced PC-12 cells, To explore the Sin's mechanism on nerve cell. METHOD: PC-12 cells were cultured with nerve growing factors (NGF), and pretreated with Sin at various concentrations (0, 3 x 10(-6), 30 x 10(-6), 150 x 10(-6) mol x L(-1)) for 2 hours, then with or without stimulation of lipopolysaccharide (LPS). The proliferation activity of PC-12 cells was determined by 3H-TdR incorporation, and the production of PGE2 in culture supernatants of PC-12 cells was detected with competitive ELISA. Expression of COX-2 mRNA in PC-12 cells was analyzed by semi-quantitative RT-PCR, and expression of COX-2 protein was estimated by Western blot method and cellular enzyme immunoassay. Nuclear factor-kappa B (NF-kappaB) activity in whole-cell extract of PC-12 cells was also measured by an ELISA-based method. RESULT: The data showed that Sin down-regulated the expression of COX-2 mRNA and protein, and reduced the production of PGE2 in the LPS-stimulated PC-12 cells which correlated with Sin's concentrations positively. In addition, NF-kappaB activity in LPS-stimulated cells was suppressed significantly by Sin. No inhibition of proliferation of PC-12 cells due to Sin treatment was observed. CONCLUSION: Sin mediates the down-regulation of expression of COX-2 and production of induced PGE2 in PC-12 cells by suppressing the activity of NF-kappaB.

Animals↗
PubMed2004

[A probability analysis for HLA matching in adult stem cell transplantation treating nervous genetic diseases].

The aim of this study was to investigate the clinical feasibility of adult stem cell transplantation for lethal mono-gene inherited disease, Duchenne muscular dystrophy (DMD). A total of 30 blood samples from DMD patients were genotyped with HLA-A,-B and -DR alleles by means of polymerase chain reaction-reverse sequence specific oligonucleotide (PCR-RSSO). The HLA gene types in 30 DMD patients were compared with those of 668 unrelated donors from Umbilical Cord Blood Center of Guangdong Province and 34 910 unrelated donors from Chinese Bone Marrow Bank. The results showed that HLA gene of the DMD group was inherited in normal distribution. There was no striking difference of HLA-A, -B and -DR alleles expression between the DMD patients group and control healthy group. 25% of the DMD patients got suitable donors for stem cell transplantation, in which 15 patients found donors with >or= 5/6 HLA match at the Umbilical Cord Blood Center of Guangdong Province, i.e. occupying 50% of the total. Eight patients got 6/6 HLA matching donors at the Chinese Bone Marrow Bank, i.e. occupying 26% of the total. It is concluded that stem cells transplantation therapy for DMD patients is feasible, which will benefit these patients suffered from the lethal neuromuscular disease, and create a new way to treat this tough nervous system disease.

Adolescent↗
PubMed2004

[Cloning and characterization of a novel human ceg1 gene cDNA].

ceg1 gene was a novel human gene, which was cloned by bioinformatics research and RT-PCR. It was a single exon gene and located on human chromosome 14. The length of the cDNA was 2050 bp. Bioinformatics analysis predicted a 1340 bp complete open reading frame (ORF) which encoded a 446 amino acid protein, containing an EGF-like and CLECT domain. We found that the homologous genes of ceg1 in mouse embryo and chicken embryo were specifically expressed in the brain by in-situ hybridization. The result of RT-PCR of the mature mouse organs showed it was widely expressed in many organs. The result indicates that ceg1 gene may have an essential role in the development of brain and the maintenance of the organs' normal function. The analysis of expression and function profile of ceg1 gene may provide valuable insights into the functions of ceg1 in the development and function of human body.

Amino Acid Sequence↗
PubMed2004

[Fetal ECG monitoring system based on MCU processing].

In order to monitor the fetus in labor, the signal characteristic from fetal scalp electrode is researched, An adaptation algorithm and a peak to peak detecting technology are adopted in signal processing, and an adaptation gain control method is used to eliminate disturber from base-line shift. A fetal ECG monitoring system is designed on the basis of C8051F020 MCU.

Adult↗
PubMed2004

[Study on the ultraviolet-visible spectra of Au/Al2O3 catalysts].

A variety of synthesis parameters for the preparation of gold nanoparticles by NaBH4 solution reduction in the W/O microemulsion media consisting of Cetyl Trimethyl Ammonium Bromide (CTAB)/n-hexanol/water system was investigated. The results showed that the molar ratio of water to surfactant (rw) had nothing to do with the gold particle size, but the concentration of the aqueous gold salt solution had a significant effect on the size of gold particle. Through optimizing the preparation parameters, Au/Al2O3 catalysts were prepared with two different methods, then the catalysts were characterized by ultraviolet-visible spectra, XRD and TEM, and the effect of two different preparation methods on active component gold particle size in the catalysts was studied.

English Abstract↗
PubMed2004

[Self-assembly and characterization of Pt nanoparticles by electrochemistry and in-situ FTIR reflection spectroscopy].

Pt nanoparticles (Pt(n)) were prepared by chemical reduction method. The average dimension of Pt(n) is about 2.5 nm in diameter determined from TEM studies. The Pt nanoparticles were then self-assembled on massive Au substrate. The process of self-assembly was investigated with Fe(CN)(4-/3-)(6) for redox probe reaction. The result showed that the dithiol assembled on Au surface is inactive for electron transfer. However after assembly of Pt nanoparticles on the dithiol, the Au/SS-Pt(n) electrode becomes conductive again for electron transfer. The adsorption of CO on the Pt nanoparticles self-assembled on Au substrate in 0.1 mol x L(-1) H2SO4 was studied by using in situ FTIR reflection spectroscopy. IR absorption of linear and bridge bonded CO species was observed around 2030 and 1845 cm(-1) respectively. IR absorption of twin bounded CO adsorbed on the Pt nanoparticles was also observed about 2100 cm(-1). The results illustrated that the IR absorption of CO adsorbed on the Pt nanoparticles has been significantly enhanced. The present study is devoted to revealing the intrinsic properties of self-assembly system of nanoparticles, and is of importance in applications of electrocatalysis as well.

Catalysis↗
PubMed2004

[Study on the establishment of data management system of emergency response in fighting against flooding in China].

OBJECTIVE: To make the emergency response to the diseases control and prevention with flooding more scientific ally-based and efficient. METHODS: Hubei and Jiangxi province were chosen as the study fields and to establish a data management system of emergency response on flooding using remote sensing (RS) and geographical information system (GIS). RESULTS: Spatial and basic data together with data on flooding were linked to the code of location, and established on the platform of GIS. Through this system, information on flooding was able to be more rapidly and visually analysed. CONCLUSION: Using this system, the extent of flooding and the possible epidemic of some communicable diseases during flooding could be ascertained and predicted scientifically and the resource and capacity of emergency response to the disease control and prevention in flooding areas could also be evaluated.

China↗
PubMed2004

[Photosynthetic characteristics of main urban forest species Syringa oblata in Shenyang].

Using LI-6400 CO2 gas analysis system and by the methods of correlation analysis and multinomial regression, this paper studied the diurnal changes of Syringa oblata photosynthesis during different seasons and assessed the correlation between net photosynthetic rate and environmental factors. The results indicated that the photosynthetic rate showed a double-peak curve in spring and summer and a single peak curve in autumn. The major factors affecting the photosynthetic rate were the solar radiation and stomatal conductance in spring and summer, and the stomatal conductance and intercellular CO2 intensity in autumn. The related equation was also constructed in this paper.

China↗
PubMed2004

[Expression, purification and characterization of the recombinant anthrax protective antigen].

An expression plasmid carrying anthrax protective antigen (PA) gene was constructed, which has an OmpA signal sequence attached to the 5' end of PA gene. The plasmid was transformed into E. coli and induced to express recombinant PA (rPA) . The recombinant protein, about 10% of the total bacterial protein in volume, was secreted to the periplasmic space of the cell. After a purification procedure including ion-exchange, hydrophobic interaction chromatography, and gel filtration, about 15 mg of 95 % pure rPA was obtained from 1-liter culture. The bioactivity of rPA was proved by in vitro cytotoxicity assay. The polyclonal antiserum from rabbits immunized with rPA could inhibit the action of anthrax lethal toxin in vitro, which suggests that antibodies against rPA can provide high passive protection against anthrax. The results reported here may be helpful to develop a safe and efficacious recombinant PA vaccine against anthrax.

Amino Acid Sequence↗