PubMed Health⌕ Search

Biomedical subjects

Jing Chen

Publications and source records attributed to Jing Chen.

At least 199 records · Page 11Linked to original sources
PubMed2005

[Effects of simulated nitrogen deposition on weeds growth and nitrogen uptake].

In this paper, a greenhouse experiment was conducted to study the responses of different functional groups weeds to simulated nitrogen deposition (4.0 g N.m(-2).yr(-1)). Native weed species Poa annua, Lolium perenne, Avena fatua, Medicago lupulina, Trifolium repens, Plantago virginica, Veronica didyma, Echinochloa crusgalli var. mitis, Eleusine indica and Amaranthus spinosus in orchard ecosystem were used test materials, and their above-and underground biomass and nitrogen uptake were measured. The results showed that under simulated N deposition, the total biomass, shoot biomass and root biomass of all weed species tended increase, while the total biomass was differed for different functional groups of weeds. The biomass of C4 grass, legumes and C3 grass was significantly increased under N deposition, while that of C3 and C4 forbs was not significantly impacted. The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition, but that of Poa annu, Lolium perenne, Medicago lupulina, Trifolium repens and Amarathus spinosus was not impacted significantly. N deposition had no significant effect on plant N concentration, but significantly enhanced the N uptake of all test weed species except Amarathus spinosus, Poa annua and Veronica didyma. was suggested that the further increase of N deposition might speed up the changes of the community structure weed species due to their different responses to N deposition.

Avena↗
PubMed2005

[Preventive effects and mechanism of heme oxygenase-1 activation on acute respiratory distress syndrome in rats].

OBJECTIVE: To explore the possible mechanism of heme oxygenase-1 (HO-1) induction for its protective effects on acute respiratory distress syndrome (ARDS). METHODS: The production of HO-1 was induced by hemoglobin (Hb) injection into oleic acid (OA) induced ARDS rats. Western blot and RT-PCR techniques were used to observe the induction of HO-1 in vivo. Both the levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) in serum and bronchoalveolar lavage fluid (BALF) were measured by enzyme linked immunosorbent assay (ELISA). Combined with blood gas analysis and other indexes, the effect of HO-1 on ARDS could be clearly manifested. RESULTS: The expression of HO-1 mRNA was increased significantly 16 h after Hb injection, and the protein expression of HO-1 was also obviously increased 24 h later (P < 0.01). The levels of TNF-alpha and IL-8 in both serum and BALF were significantly lower in Hb + OA group than in OA group (P < 0.01). Arterial blood PaO(2), oxygen saturation, and oxygenated index in Hb + OA group [(56.28 +/- 6.71) mm Hg, (79.53 +/- 5.82)%, and (258.81 +/- 29.37) mm Hg respectively] were higher than in OA group [(35.08 +/- 4.59) mm Hg, (55.80 +/- 12.76)%, and (167.86 +/- 21.94) mm Hg]. Lung wet and dry weight, and pathological changes were also improved. CONCLUSION: The production of HO-1 was successfully induced by hemoglobin in vivo. Protective effects of HO-1 on ARDS might be related to the decreasing in inflammatory factors, such as TNF-alpha and IL-8.

Animals↗
PubMed2005

[Effect of zinc on thymulin level in mice].

OBJECTIVE: In order to investigate the roles of the different levels of zinc nutrition status on the thymulin of the mice. METHODS: The experiment included two periods: zinc depleted period and repletion period. In the depleted period, mice were divided into 3 dose groups: zinc deficient group (ZD, 5.2 mg/kg), zinc pair-fed group (PZ) and normal zinc group(NZ,25.6 mg/kg). In the repletion period, mice were divided into 3 dose groups: ZD group, DZ-NZ group and PZ-NZ group. RESULTS: The results showed that a signification decrease of thymulin level was observed as a result of zinc deficiency and was increased rapidly follow zinc supplement, while the plasma zinc was kept the same level. CONCLUSION: The thymulin is a sensitive biomarker for assess the zinc status.

Animals↗
PubMed2005

[Biological characteristics of mesenchymal stem cells from bone marrow of patients with aplastic anemia].

To investigate the differences of proliferation capacity and phenotype properties of mesenchymal stem cells (MSCs) derived from bone marrow (BM) of aplastic anemia patients, fetuses and children, MSCs were isolated from BM of patients with aplastic anemia and expanded in vitro; MSCs derived from BM of fetuses and children were used as normal control groups, three sources of MSCs were compared by morphology, in vitro proliferation capacity, phenotype and immunocytochemistry. The results showed that MSCs could be isolated and expanded from aplastic anemia patient BM. MSCs derived from BM of aplastic anemia patients shared a similar morphology and phenotype with derived MSCs from BM of fetuses and children. However, in vitro proliferation capacity of MSCs derived from BM of aplastic anemia patients after 20 population doublings (PD) was significantly lower, compared with MSCs from BM of fetuses and children. BM MSCs derived from children and fetuses proliferated for more than 30 PD. It is concluded that BM MSCs from aplastic anemia patients appears to be normal in phenotype but their proliferation capacity is lower in comparison with control groups.

Anemia, Aplastic↗
PubMed2005

[Expression of fusion protein of parathyroid hormone and transferrin N-terminal half-molecule in Pichia pastoris].

The fused gene (PTH-TFN) of parathyroid hormone (PTH) gene and transferring N-terminal half-molecule (TFN) gene was amplified by multiple PCR and inserted into pPIC9 vector. The recombinant plasmid pPIC9-PTH-TFN was transformed into Pichia pastoris GS115 by PEG. After methanol induction, the target protein was expressed in fermentation supernatant at high level. The fused protein PTH-TFN with purity being higher than 95% was finally obtained after purification through two-step chromatography: SP Sepharose Fast Flow and Phenyl Sepharose Fast Flow. Western blot analysis and adenylate cyclase assay proved that the fused protein exhibited the bioactivity to stimulate cAMP synthesis and the ability to bind Fe3+ in the Fe3+ saturation study as the recombinant TFN did indicating that TFN could be used as the transcellar carrier of PTH.

Artificial Gene Fusion↗
PubMed2005

[Effects of needling in Baihui (DU20), Shuigou (DU26) and Shenmen (HT7) on glucose metabolism in the lentiform nucleus in patients with vascular dementia].

OBJECTIVE: To observe the effect of needling in Baihui (DU20), Shuigou (DU26) and Shenmen (HT7) on glucose metabolism in the lentiform nucleus in patients with vascular dementia. METHODS: Ten patients with vascular dementia were randomized equally into control group to receive the treatment of needling in the routine acupoints for hemiplegia (chosen from 6 Yang meridians of hand and foot) and treatment group with needling in 3 additional acupoints of Baihui (DU20), Shuigou (DU26) and Shenmen (HT7) for dementia. All the patients were examined by positron emission tomography (PET) to detect glucose metabolism in the bilateral lentiform nuclei before and after treatment. RESULTS: Glucose metabolism in the lentiform nucleus in normal lateral brain was obviously enhanced in the treatment group, but not in the bilateral lentiform nuclei in the control group after treatment. CONCLUSION: The effect of needling in Baihui (DU20), Shuigou (DU26) and Shenmen (HT7) for treatment of vascular dementia may involve the enhancement of glucose metabolism in the lentiform nucleus.

Acupuncture Points↗
PubMed2005

[Edit and evaluation of Mandarin sentence materials for Chinese speech audiometry].

OBJECTIVE: To edit the sentence list for mandarin speech test materials (MSTM) and to test their equivalence in order to use the list as routine clinical speech tests for evaluation of cochlear implants and hearing aids in different stages of the intervention and rehabilitation. METHODS: Firstly, two groups of professionals were set up: one for establishing the principles of the edit, another for experiments. The criteria to guide the selection of spoken sentences were as following: (1) suitable for everyday speech audiometry, esp. clinically usage; (2) a normal sampling of everyday spoken sentences in mandarin. Totally, 300 sentences were selected in 30 lists for the experiment. The record cassette was used by a male speaker. The college students (54 persons,54 ears) with normal hearing participated in the equivalence test. Two statistic methods were used for equivalence analysis. RESULTS Through speech tests and statistic analysis, 2 sets with 29 lists (290 sentences) were selected as our equivalent lists for further evaluation and clinical trial. CONCLUSIONS: By setting up the strict criteria of selecting sentences, speech test method and statistic analysis, 2 sets of 29 lists (290) sentences were chosen as our speech evaluation materials, but it was necessary for further analysis in different laboratories and clinics. The sentence lists should also get used for hearing impaired subjects, hearing aid users and cochlear implant recipients.

Adult↗
PubMed2005

[Study on extraction methods of volatile oil from Mosla soochowensis].

OBJECTIVE: To study the different extraction methods of the volatile oil from Mosla soochowensis Matsuda and to determine the optimum extraction method. METHODS: The yields and the chemical constituents of volatile oil were used to compare the different extraction methods including SFE-CO2, steam distillation and organic solvent (petroleum ether) extraction. RESULTS: The yield of volatile oil by means of SFE-CO2 was 3.46%, which was higher than others. The quality of the oil by means of SFE-CO2 and steam distillation was better. Based on the result of GC-MS, the constituents of volatile oil were similar. It was mainly the methyleugenol, accounted for about 42%. The second was monocyclic terpene, such as bornene, dihydrocarvon, carvacrol, accounted for about 27%. The third was sesqutierpenoids, such as nerolidene etc, accounted for about 19%. CONCLUSION: SFEE-CO2 is the optimum extraction method of the volatile oil from Mosla soochowensis Matsuda.

Carbon Dioxide↗
PubMed2005

[Effect of zinc on immune function in mice spleen lymphocytes].

OBJECTIVE: In order to study the effects of different levels of zinc nutrition status on the immune function of mice spleen lymphocytes. METHODS: The experiment included two periods: zinc depleted period and repletion period. In the depleted period, mice were divided into 3 dose groups: zinc deficient group (ZD, 5.2mg/kg), zinc pair-fed group (PZ) and normal zinc group (NZ, 25.6 mg/kg). In the repletion period, mice were divided into 3 dose groups: ZD group, DZ-NZ group and PZ-NZ group. It was measured some biomarkers of immunity to assess the zinc nutritional status, including lymphocytes amount, lymphocytes proliferation index and IL-2 activity. RESULTS: The lymphocytes counts of ZD group spleen showed significant decline at seventy days fed zinc deficiency diets. The counts of ZD-NZ group were increased after 22 days of taking normal zinc diet. Zinc deficiency could suppressed the proliferation of the spleen lymphocytes. The spleen lymphocytes proliferation of the ZD-NZ group showed a moderate but non-significant increase compared with the ZD group. Zinc deficiency could decrease IL-2 production. The production of IL-2 of ZD group was lower than those of ZP (P < 0.05), IL-2 production increased following zinc supplement. CONCLUSION: It is found that zinc status can affect the immune function. Production of IL-2 in spleen lymphocyte is affected evidently by zinc.

Animals↗
PubMed2004

A yeast two-hybrid technology-based system for the discovery of PPARgamma agonist and antagonist.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is an important therapeutic drug target against several diseases such as diabetes, inflammation, dyslipidemia, hypertension, and cancer. Ligand binding to PPARgamma is responsible for controlling the biological functions, and developing new technology to measure ligand-PPARgamma binding is significant for both the function study of the receptor and ligand discovery. In this study, we exploited an efficient approach for the discovery of PPARgamma agonist and antagonist via a yeast two-hybrid system based on the fact that PPARgamma interacts with the coactivator CBP (CREP-binding protein) ligand-dependently. We employed the MEL1 reporter gene instead of the traditionally used LacZ gene to evaluate the protein-protein interactions by conducting a convenient alpha-galactosidase assay in the yeast strain AH109 with genes of PPARgamma-LBD (ligand-binding domain) and CBP N terminus introduced. With this built screening platform, the EC(50) values of the PPARgamma agonists rosiglitazone, troglitazone, pioglitazone, indomethacin, 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)), and GI262570 were investigated, and the quantitatively antagonistic effect by IC(50) of the PPARgamma typical antagonist GW9662 on the rosiglitazone agonistic activity was fully examined. The reliability of this presented system evaluated by the comparable agreement of EC(50) and IC(50) values for the test compounds with the reported ones indicated that this yeast two-hybrid-based approach is powerful for PPARgamma agonist and antagonist screening. In addition, because this screening system is designed for use in a microtiter plate format where numerous chemicals could be readily screened, it is hoped that this yeast two-hybrid screening approach may be adaptable for high-throughput settings.

Anilides↗
PubMed2004

In vitro biochemical and thermodynamic characterization of nucleocapsid protein of SARS.

The major biochemical and thermodynamic features of nucelocapsid protein of SARS coronavirus (SARS_NP) were characterized by use of non-denatured gel electrophoresis, size-exclusion chromatographic and surface plasmon resonance (SPR) techniques. The results showed that SARS_NP existed in vitro as oligomer, more probably dimer, as the basic functional unit. This protein shows its maximum conformational stability near pH 9.0, and it seems that its oligomer dissociation and protein unfolding occur simultaneously. Thermal-induced unfolding for SARS_NP was totally irreversible. Both the thermal and chemical denaturant-induced denaturation analyses showed that oligomeric SARS_NP unfolds and refolds through a two-state model, and the electrostatic interactions among the charge groups of SARS_NP made a significant contribution to its conformational stability.

Chromatography, Gel↗
PubMed2004

A new subtype of 3' region of cagA gene in Helicobacter pylori strains isolated from Zhejiang Province in China.

AIM: To isolate the subtypes of 3' region of cagA gene in Helicobacter pylori (H pylori) strains from Zhejiang Province in China and to investigate their relations to H pylori-associated gastroduodenal diseases. METHODS: One hundred and thirty-seven H pylori clinical strains were isolated from the gastric mucosa specimens of 74 patients with chronic gastritis, 61 with peptic ulceration, and 2 with gastric cancer. Bacterial genomic DNA was extracted and 3' region of cagA gene was amplified by polymerase chain reaction (PCR). Subtypes of 3' region of cagA gene were determined by the size of PCR amplified segments. The sequences of the subtypes were analyzed by PCR-based sequencing. RESULTS: Of the 137 H pylori isolates from Zhejiang Province, 132 (96.4%) yielded PCR products that could be classified into three groups of subtypes, named as subtypes I, II, and III according to their sizes. The sizes of subtypes I, II, and III were 648-650 bp, 705-707 bp, and 815 bp, respectively. Among the 132 cagA-positive H pylori strains, 123 (93.2%) belonged to the group of subtype I, 6 (4.5%) presented subtype II, 1 (0.8%) was subtype III, and 2 (1.5%) presented subtypes I and III both. The primary structure of subtype I was composed of 3 repeats of R1, 1 repeat of R2 and 1 repeat of R3. Subtype II possessing 4 repeats of R1, 2 repeats of R2 and 1 repeat of R3 was a newly found type of 3' region of cagA gene which had not been reported before. The primary structure of subtype III consisted of 4 repeats of R1, 1 repeat of R2 and 2 repeats of R3. Comparison of the sequences of subtype I strains with the corresponding sequences deposited in GenBank, showed a similarity of 95.0% (94.0-96.1%) for nucleotide sequences and 95.9% (94.9-97.4%) for deduced amino acid sequences. Comparison of the sequences of subtype III strains with the corresponding sequences deposited in GenBank, showed a similarity of 93.9% (90.8-96.9%) for nucleotide sequences and 93.2% (90.2-96.2%) for deduced amino acid sequences. Among subtype II strains, the nucleotide and deduced amino acid sequences showed a similarity of 95.2% (94.1-96.5%) and 96.4% (93.8-97.9%), respectively. There were no statistical differences in the distribution of subtypes of 3' region of cagA gene among different H pylori-associated gastroduodenal diseases (chi(2) = 11.544, P>0.05). CONCLUSION: There are three subtypes (I, II, and III) of 3' region of cagA gene in H pylori strains isolated from Zhejiang Province, and subtypeIis predominant. Subtype II is a newly found subtype of 3' region of cagA gene. The result of this study does not support the view that the subtypes of 3' region of cagA gene in H pylori isolated from Zhejiang Province are correlated with the clinical outcomes of H pylori infection.

Adolescent↗
PubMed2004

[The role of Cubilin in albumin-induced MCP-1, RANTES expression by renal tubular epithelial cells].

OBJECTIVE: To study the molecular mechanism of albumin-induced MCP-1 and RANTES expression by renal tubular epithelial cells (RTECs). METHODS: Ten nephrotic syndrome patients and eight hematuric patients were collected into this study. In vivo, albumin deposition, MCP-1 and RANTES expression in kidney tissues from these patients were examined by immunochemistry. In vitro, expression vector harboring sense or antisense cubilin gene fragment was transfected into HK2 cells with lipofectin DOTAP. Endocytosis of FITC labeled human serum albumin (FITC-HSA) by RTECs was detected by fluorescent microscope. MCP-1 and RANTES expression were determined by Western blot analysis. RESULTS: Under the light microscope, normal histological configuration was observed in the hematuric patients; obvious tubulointerstitial lesions such as inflammatory cell infiltration, tubular cell atrophy and tubulointerstitial fibrosis were shown in the nephrotic syndrome patients. By immunohistochemistry study, only a small quantity of albumin were found within the RTECs in the hematuric patients; but a large amount of albumin were seen within the RTECs and interstitium in the nephrotic syndrome patients. MCP-1 and RANTES were weakly expressed in the hematuric patients; but very strongly expressed in the nephrotic syndrome patients. In vitro, cubilin expression by HK2 cells was obviously inhibited by antisense cubilin (pCDNA-ACUB). HSA-FITC uptake was lower in HK2 cells transfected with pCDNA-ACUB than in the cells harboring sense cubilin (pCDNA-CUB) or Vector (pCDNA3.1(+)). Both MCP-1 and RANTES expression were significantly suppressed in HK2 cells transtected with pCDNA-ACUB when compared with the cells harboring pCDNA-CUB or pCDNA3.1(+), respectively. CONCLUSION: Excessive albumin reabsorption may have close relationship with over-expression of MCP-1 and RANTES by RTECs, which might be responsible for the tubulointersitial injury associated with proteinuria. Cubilin may play a key role in regulation of this process.

Adult↗
PubMed2004

Severe acute respiratory syndrome coronavirus 3C-like proteinase N terminus is indispensable for proteolytic activity but not for enzyme dimerization. Biochemical and thermodynamic investigation in conjunction with molecular dynamics simulations.

Severe acute respiratory syndrome (SARS) coronavirus is a novel human coronavirus and is responsible for SARS infection. SARS coronavirus 3C-like proteinase (SARS 3CL(pro)) plays key roles in viral replication and transcription and is an attractive target for anti-SARS drug discovery. In this report, we quantitatively characterized the dimerization features of the full-length and N-terminal residues 1-7 deleted SARS 3CL(pro)s by using glutaraldehyde cross-linking SDS-PAGE, size-exclusion chromatography, and isothermal titration calorimeter techniques. Glutaraldehyde cross-linking SDS-PAGE and size-exclusion chromatography results show that, similar to the full-length SARS 3CL(pro), the N-terminal deleted SARS 3CL(pro) still remains a dimer/monomer mixture within a wide range of protein concentrations. Isothermal titration calorimeter determinations indicate that the equilibrium dissociation constant (K(d)) of the N-terminal deleted proteinase dimer (262 microm) is very similar to that of the full-length proteinase dimer (227 microm). Enzymatic activity assay using the fluorescence resonance energy transfer method reveals that N-terminal deletion results in almost complete loss of enzymatic activity for SARS 3CL(pro). Molecular dynamics and docking simulations demonstrate the N-terminal deleted proteinase dimer adopts a state different from that of the full-length proteinase dimer, which increases the angle between the two protomers and reduces the binding pocket that is not beneficial to the substrate binding. This conclusion is verified by the surface plasmon resonance biosensor determination, indicating that the model substrate cannot bind to the N-terminal deleted proteinase. These results suggest the N terminus is not indispensable for the proteinase dimerization but may fix the dimer at the active state and is therefore vital to enzymatic activity.

Binding Sites↗
PubMed2004

Induction of apoptosis and tumor regression by vesicular stomatitis virus in the presence of gemcitabine in lung cancer.

Vesicular stomatitis virus (VSV) has been shown to replicate rapidly in vitro and kill selectively a variety of tumor cell lines. The present study was designed to determine whether gemcitabine potentiates the antitumor activity of VSV in vitro and in vivo. A549 human lung adenocarcinoma cells and LLC Lewis lung carcinoma cells were treated with VSV (0.1-10 plaque-forming units per cell) plus gemcitabine (20 nM to 20 microM). Mice bearing A549 or LLC were treated with VSV (5 x 10(4) to 1 x 10(8) plaque-forming units) daily for 5 days plus gemcitabine (5-125 mg/kg/day) once every 3 days for 4 times. Induction of apoptosis and effects on growth inhibition were assessed. The lung cancer cells treated with VSV plus gemcitabine displayed the apparently increased apoptotic cells compared with treatment with VSV or gemcitabine alone. The combined treatment with VSV plus gemcitabine induced the apparent antitumor activity with complete regression of the established lung cancer in both A549 and LLC lung cancer models and augmented the induction of apoptosis in lung cancer cells in vivo as well. This study suggests that the combined treatment with VSV plus gemcitabine may augment the induction of apoptosis in lung cancer cells in vitro and in vivo, and that the augmented antitumor activity in vivo may result from the increased induction of apoptosis in lung cancer cells. The present findings may be of importance to the further exploration of the potential application of this combined approach in the treatment of lung cancer.

Adenocarcinoma↗
PubMed2004

Dehydroepiandrosterone-sulfate did not mitigate sickness behavior in mice.

In response to lipopolysaccharide (LPS), macrophages secrete cytokines that transmit a message to the brain and induce sickness behavior. Because dehydroepiandrosterone (DHEA) and its sulfated ester (DHEA-S) reportedly improve mental health and modulate cytokine production, we hypothesized that DHEA-S administration would inhibit LPS-induced sickness behavior. Mice were provided drinking water with 0% or 0.01% DHEA-S for 2 weeks and then injected intraperitoneally with saline or LPS (1 microg). Sickness behavior was quantified using a social investigation paradigm, and DHEA-S in plasma and brain was determined at the study's end. DHEA-S did not affect water intake, food intake, or body weight during the 2-week period. As anticipated, LPS depressed social behavior. The maximum depression was observed 2 h postinjection, after which social investigation steadily increased until returning to baseline level at 8 h. DHEA-S did not mitigate the effects of LPS on social behavior even though DHEA-S in plasma and brain was increased 150- and 6-fold, respectively, in mice given DHEA-S. In a separate study, mice were given DHEA-S for 3 months and then challenged with LPS. Consistent with the first study, LPS reduced social behavior irrespective of DHEA-S treatment. However, 3 months administration of DHEA-S reduced the depression from baseline after injection of saline or LPS. DHEA-S in plasma and brain for mice given DHEA-S for 3 months was similar to that observed after 2 weeks. Collectively, these results suggest that DHEA-S has neuromodulatory effects but is ineffective at ameliorating LPS-induced sickness behavior.

Animals↗