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Biomedical subjects

Jing Chen

Publications and source records attributed to Jing Chen.

At least 91 records · Page 5Linked to original sources
PubMed2006

Extended conversion coefficients for use in radiation protection of the embryo and fetus against external neutrons from 10 MeV to 100 GeV.

External neutron exposure is of concern in the environment and in some workplaces. Dose assessments for neutrons frequently rely on fluence-to-absorbed dose conversion coefficients. A problem of concern in radiation protection is exposure of pregnant women to ionizing radiation because of the high radiosensitivity of the embryo and fetus. While neutron fluence-to-dose conversion coefficients for adults are recommended in ICRP publications and ICRU reports, conversion coefficients for embryos and fetuses are not given in the publications. This study uses the Monte Carlo code MCNPX to determine mean absorbed doses to the embryo and fetus when the mother is exposed to neutron fields. A previous study has dealt with neutrons from 1 eV to 10 MeV. In this study, monoenergetic neutrons ranging from 10 MeV to 100 GeV are considered. The irradiation geometries include antero-posterior, postero-anterior, lateral, rotational, and isotropic. At each of these standard irradiation geometries, absorbed doses to the fetal brain and body are calculated for the embryo of 8 wk and the fetus of 3, 6, or 9 mo. Neutron fluence-to-absorbed dose conversion coefficients are derived for the four prenatal ages. The results showed that the fetus at about 3 mo of prenatal age should receive more radiation protection to prevent long-term brain damage. During prenatal life, the fetus generally receives the highest absorbed dose per unit neutron fluence for antero-posterior irradiation. In cases where the irradiation geometry is not specified or not adequately known, conversion coefficients of AP-irradiation can therefore be used in a conservative dose assessment of fetus exposure to external neutrons.

Body Burden↗
PubMed2006

Transplantation of rat islets transduced with human heme oxygenase-1 gene using adenovirus vector.

OBJECTIVE: To investigate whether human heme oxygenase-1 (HO-1) gene has protective action on islets cultured in vitro, and to explore whether transduction of HO-1 gene to donor islets could enhance engrafted islets survival and suppress local lymphocytic infiltration in islet grafts. METHODS: Newly isolated rat islets were isolated from the Sprague-Dawley rats and were divided into 3 groups in vitro study as follows: enhanced green fluorescent protein (EGFP) group, islets transduced with adenovirus vectors containing EGFP gene using multiplicities of infection (MOI) = 2, 5, 10, and 20 to determine the transduction efficacy; HO-1 group, islets transduced with adenovirus vectors containing human HO-1 gene using MOI = 20; and control group, mock transduced islets. Flow cytometry was used to detect apoptotic cells after induction by recombinant human tumor necrosis factor-alpha (rTNF-alpha) and cycloheximide (CHX) for 48 hours. Diabetic recipients were randomly divided into the following groups: HO-1 group (n = 9), receiving islets transduced with recombinant adenovirus-HO-1; control group (n = 9), receiving mock transduced islets; and phosphate buffer solution (PBS) group (n = 6), receiving only 0.8 mL PBS. About 1200 rat islet equivalents were transplanted into each recipient rendered by streptozotocin using the portal vein as transplant site. Allograft survival, apoptosis, and the state of lymphocytic infiltration were analyzed. RESULTS: After treatment with rTNF-alpha and CHX, the apoptotic ratio of islet cells was 4.22% +/- 2.38% in the HO-1 group (MOI = 20), significantly lower than 23.81% +/- 8.51% in the control group (P < 0.05), and 28.76% +/- 14.76% in the EGFP group (MOI = 20; P < 0.05). Maintenance of normoglycemia was prolonged in the HO-1 group, indicated by results that islet survival time was 10.56 +/- 4.33 days significantly longer than that of untreated islets which was 5.33 +/- 4.18 days (P < 0.05). The lymphocytic infiltration degree in engrafted islets treated with HO-1 gene was lower than that in the control group. CONCLUSIONS: HO-1 gene overexpression in rat islets by adenovirus transduction can protect cultured islets against rTNF-alpha and CHX-mediated cytotoxicity. HO-1 gene has cytoprotective effects on engrafted islets, which could prolong engrafted islets survival in allogenic transplantation model, and diminish the degree of lymphocytic infiltration in islet grafts. These findings suggest a potential therapeutic application for HO-1 gene in improving islet survival/function in human islet transplantation.

Adenoviridae↗
PubMed2006

Amino acid 1-209 is essential for PDX-1-mediated repression of human CMV IE promoter activity.

AIM: To explore the different roles of pancreatic duodenal homeobox factors-1 (PDX-1) domains in PDX-1 mediated repression of human cytomegalovirus immediately early (CMV IE) promoter. METHODS: A series of truncated PDX-1 mutants were constructed. The binding of PDX-1 and CMV IE promoter was identified by electrophoretic mobility shift assay (EMSA). The dual-reporter assay was applied to examine the repression activities of PDX-1 mutants on CMV IE promoter. In addition, RNAi technology was used to specifically knock down the endogenous PDX-1 expression. RESULTS: The reporter assay indicated that compared to the mock controls (pEGFP-N2), overexpression of PDX-1 resulted in a 41% decrease of CMV IE promoter activity in the 293 cells (P< 0.05) and 43% decrease in HeLa cells (P< 0.05), and the repression levels of various truncated mutants played on CMV IE promoter were different. Specific knock down of the endogenous PDX-1 expression significantly restored the activity of CMV IE promoter. EMSA demonstrated that domain 3 is necessary for nuclear localization and DNA binding activity of PDX-1. However, binding of PDX-1 alone to CMV IE promoter was not sufficient to inhibit its transcriptional activity, and other domains of PDX-1 presented were also required. CONCLUSION: Our data suggested that the DNA binding activity of PDX-1 domain 3 and the cooperative binding of PDX-1 domain 1/2 with other proteins were required for PDX-1 mediated repression of CMV IE promoter.

Base Sequence↗
PubMed2006

A taxonomic study of Oconnorella (Enchytraeidae, Oligochaeta) from Changbaishan Mountain, China.

We describe three enchytraeid species, including two new species, from Mt. Changbaishan, Jilin Province, northeastern China. Oconnorella cheni sp. nov. is characterized by a simple spermatheca; absence of the oesophageal appendages and seminal vesicle; and nephridia from 6/7, with a distinct funnel and the efferent duct arising from the anterior part of the postseptale. Oconnorella globula sp. nov. is distinguished by a spermatheca with two diverticula; lack of oesophageal appendages and seminal vesicle; and nephridia from 6/7, with distinct funnel and the efferent duct arising from the mid-ventral or posteroventral part of the postseptale. We redescribe Oconnorella changbaishanensis (Xie et al., 2000) from type and live specimens, and amend some characters that cannot be investigated clearly from mounted specimens. We revise the generic diagnosis of Oconnorella.

Animals↗
PubMed2006

Solid phase extraction and spectrophotometric determination of Au(III) with 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine.

A new chromogenic reagent, 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine (HNATR) was synthesized. A highly sensitive, selective and rapid method for the determination microg l(-1) level of Au(III) based on the rapid reaction of Au(III) with HNATR and the solid phase extraction of the colored complex with a reversed phase polymer-based C(18) cartridge have been developed. The HNATR reacted with Au(III) to form a red complex of a molar ratio 1:2 (Au(III) to HNATR) in the presence of 0.05 - 0.5 mol l(-1) of phosphoric acid solution and emulsifier-OP medium. This complex was enriched by the solid phase extraction with a polymer-based C(18) cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 1.37 x 10(5) l mol(-1) cm(-1) at 520 nm in the measured solution. The system obeys Beer's law in the range of 0.01 - 3 microg ml(-1). The relative standard deviation for eleven replicates sample of 0.5 microg l(-1) level is 2.18%. The detection limit, based on the three times of standard deviation is 0.02 microg l(-1) in the original sample. This method was applied to the determination of gold in water and ore with good results.

Journal Article↗
PubMed2006

An overall picture of SARS coronavirus (SARS-CoV) genome-encoded major proteins: structures, functions and drug development.

A severe atypical pneumonia designated as severe acute respiratory syndrome (SARS) by The World Health Organization broke out in China and menaced to more than other 30 countries between the end of the year 2002 and June of the year 2003. A novel coronavirus called severe acute respiratory syndrome coronavirus (SARS-CoV) has been recently identified as the etiological agent responsible for the infectious SARS disease. Based on extensively scientific cooperation and almost two-year's studies, remarkable achievements have been made in the understanding of the phylogenetic property and the genome organization of SARS-CoV, as well as the detailed characters of the major proteins involved in SARS-CoV life cycle. In this review, we would like to summarize the substantial scientific progress that has been made towards the structural and functional aspects of SARS-CoV associated key proteins. The progress focused on the corresponding key proteins' structure-based drug and vaccine developments has been also highlighted. The concerted and cooperative response for the treatment of the SARS disease has been proved to be a triumph of global public health and provides a new paradigm for the detection and control of future emerging infectious disease threats.

Antiviral Agents↗
PubMed2006

Novel leptin receptor mutation in NOD/LtJ mice suppresses type 1 diabetes progression: II. Immunologic analysis.

Recently, we identified in normally type 1 diabetes-prone NOD/LtJ mice a spontaneous new leptin receptor (LEPR) mutation (designated Lepr(db-5J)) producing juvenile obesity, hyperglycemia, hyperinsulinemia, and hyperleptinemia. This early type 2 diabetes syndrome suppressed intra-islet insulitis and permitted spontaneous diabetes remission. No significant differences in plasma corticosterone, splenic CD4(+) or CD8(+) T-cell percentages, or functions of CD3(+) T-cells in vitro distinguished NOD wild-type from mutant mice. Yet splenocytes from hyperglycemic mutant donors failed to transfer type 1 diabetes into NOD.Rag1(-/-) recipients over a 13-week period, whereas wild-type donor cells did so. This correlated with significantly reduced (P < 0.01) frequencies of insulin and islet-specific glucose-6-phosphatase catalytic subunit-related protein-reactive CD8(+) T-effector clonotypes in mutant mice. Intra-islet insulitis was also significantly suppressed in lethally irradiated NOD-Lepr(db-5J)/Lt recipients reconstituted with wild-type bone marrow (P < 0.001). In contrast, type 1 diabetes eventually developed when mutant marrow was transplanted into irradiated wild-type recipients. Mitogen-induced T-cell blastogenesis was significantly suppressed when splenic T-cells from both NOD/Lt and NOD-Lepr(db-5J)/Lt donors were incubated with irradiated mutant peritoneal exudate cells (P < 0.005). In conclusion, metabolic disturbances elicited by a type 2 diabetes syndrome (insulin and/or leptin resistance, but not hypercorticism) appear to suppress type 1 diabetes development in NOD-Lepr(db-5J)/Lt by inhibiting activation of T-effector cells.

Adoptive Transfer↗
PubMed2006

[Progress in the study on DREB transcription factor].

DREB transcription factor is a dehydration responsive element (DRE) binding protein. It can specifically interact with the dehydration-responsive element/C-repeat (DRE/CRT) cis-acting element contained in the promoter region of many stress-inducible genes, and can therefore control the expression of many stress-inducible genes in plant and increase strong tolerance to drought, low temperature and high salt. In this paper we described the relation between DREB transcription factor and DRE/CRT cis-acting element, the functional and structural character, and expression and regulation of DREB. We also briefly introduced the progress of research on DREB gene cloning and identification. DREB transcription factor plays an important role in the expression of many stress-inducible genes in plant, so it thus shows a very broad application future in aspect of increasing strong tolerance to stress. At the same time, we described the DREB complexity in signal transduction and the mechanism for action and expression of gene.

Gene Expression Regulation, Plant↗
PubMed2006

[Clinical observation on chiropractics combined with acupuncture at Sifeng (EX-UE 10) for treatment of infantile anorexia].

OBJECTIVE: To search for an effective therapy for infantile anorexia. METHODS: Sixty-two cases of infantile anorexia were randomly divided into a treatment group and a control group, 31 cases in each group. The treatment group were treated with chiropractics plus acupuncture at Sifeng (EX-UE 10), and the control group with oral administration of zinc gluconate granules made by the pharmaceutical factory of the hospital, for 2 weeks. RESULTS: The effective rate was 93.5% in the treatment group, which was better than 74.2% in the control group (P < 0.05); there were significant differences in blood zinc content and urinary amylase activity in the two groups before and after treatment (P < 0.01), with more significant increase in the treatment group as compared with the control group (P < 0.05). CONCLUSION: Chiropractics combined with acupuncture at Sifeng (EX-UE 10) has a better therapeutic effect on infantile anorexia.

Acupuncture Points↗
PubMed2006

[Effect of surfactants on biodegradation of PAHs by white-rot fungi].

The impacts of surfactants (Tween80, Trition X-100, LAS and SDS) on PAHs degradation by white-rot fungi in aqueous system and soil-water system were studied. Results show that the type and concentration of surfactants, PAHs statues, pH value of the systems and temperature have impacts on the degradation of PAHs. In aqueous system, all the four surfactants restrained the degradation of PAHs. In soil-water system, Trition X-100 and SDS restrained the degradation of PAHs, while the impacts of Tween80 and LAS on PAHs degradation were influenced by the concentration of the surfactants. Low concentration Tween80 and LAS didn't promote the degradation of PAHs, and even played minor effects of restrain. But the degradation of PAHs could be enhanced with the increasing of the concentrations of Tween80 and LAS to certain levels. However, Tween80 and LAS with significant higher concentrations didn't show higher abilities on the promotion of PAHs degradation.

Biodegradation, Environmental↗
PubMed2006

[Study on mRNA expression of the human novel gene NM23-H1B in ovarian tumor].

OBJECTIVE: To study the expression of the human novel gene NM23-H1B in ovarian cancer. METHODS: Forty-eight samples from patients with ovarian tumor at different clinical stages and 8 from normal ovaries were examined for NM23-H1B mRNA expression by using RT-PCR, northern blot and in situ hybridization. RESULTS: All samples expressed NM23-H1B mRNA through RT-PCR, while the level of expression in ovarian tumor was higher than that of normal ovary. The level of expression in early stage (stage I and II) cancer was higher than in advanced (stage III and IV) cancer. The results of northern blot showed that NM23-H1B was over expressed in ovarian cancer while low expressed in normal ovary or low malignant potential (LMP) ovarian cancer. In early stage carcinoma, the expression level was related with the differentiation of tumor cell. Well-differentiated cancer expressed NM23-H1B mRNA at comparatively higher level. The result of in situ hybridization showed that positive expression rate of NM23-H1B mRNA in ovarian cancer (100%, 40/40) was significantly higher than that in normal ovary (0/8) or LMP ovarian cancer (2/8). CONCLUSION: The novel gene NM23-H1B is related to ovarian cancer.

Adolescent↗
PubMed2006

[Desorption of polycyclic aromatic hydrocarbons from soil in presence of surfactants].

Four types of surfactant were used to study their effects on polycyclic aromatic hydrocarbons (PAHs) desorption from artificially contaminated and oil-contaminated soil. The results show that the desoption of PAHs from soil is affected by the type and concentration of surfactant and also by the character and state of PAHs. Surfactants don't improve PAHs desorption from soil when their concentrations are below or near their critical micelle concentration (CMC) values. While, surfactants could obviously enhance the desorption process when the concentrations exceeded the CMC values. The desorption ratios of PAHs were increasing with the increase of surfactant concentrations. Comparatively, lower hydrophile lipophile balance(HLB) can lead to more obvious surfactant solubilization. There were linear relationship between PAHs desorption ratio and PAHs lgKow value. The desorption ratio of PAHs in artificially contaminated soil was higher than in oil-contaminated soil.

Adsorption↗
PubMed2006

[Maximum acceptable weight of lift for manual lifting tasks].

OBJECTIVE: To explore the maximum acceptable weight of lift (MAWL) in different lifting conditions and the suitable lifting equation for the stipulation of occupational health standard of manual lifting tasks in China. METHODS: The MAWL was investigated among the thirteen male and ten female students using psychophysical methodology and the recommended weight of limit (RWL) was compared. RESULTS: The MAWL of male and female subjects was decreased gradually with the increase of lifting height. Once the height of lifting was over shoulder, the MAWL was decreased dramatically. The RWL was greater than the MAWL at 25 cm horizontal distance in male subjects, but the RWL was smaller than the MAWL at the distance of 45 cm and 63 cm. The average MAWL of male subjects was 30.8% greater than that of female subjects. The MAWL was decreased gradually with increase of the horizontal distance at the same height of lifting. The result of the male subjects was consistent with that of the female subjects. For the asymmetric lifting tasks of the male subjects, the bigger the angle of rotation was, the less the MAWL became. The angle of rotation had negative correlation with the capability of lifting (r = -0.996 6, P < 0.01). When the subjects performed asymmetric lifting tasks, the RWL was smaller than the MAWL and the difference was significant. CONCLUSION: The revision is sufficient for the horizontal distance and asymmetric lifting in the NIOSH lifting equation, but it is not suitable for height, especially for the task of lifting over shoulder. The RWL for the task of lifting over shoulder should be lowered. The factor of gender should be taken into account in the lifting equation and the constant of gender S can be added. Then S = 1 for male while S = 0.692 for female.

Adult↗
PubMed2006

[Evaluation of work load and related factors during asymmetric lifting with surface electromyography].

OBJECTIVE: To evaluate the work load and related factors for asymmetric lifting tasks using surface electromyography (EMG). METHODS: Thirteen male volunteers lifted loads of 6 and 13 kg at two speeds, in varying angles of trunk rotation, from floor to knuckle height, performing 16 lifting tasks. During lifting, surface electromyography signals from the erector spinae, bilaterally at level of T10 and L3, was continually recorded. The work load and related factors for asymmetric lifting tasks were evaluated by comparing the average amplitude of EMG signals. RESULTS: The EMG average amplitude when lifting the load of 13 kg (43.30% MVE) was significantly greater than that when lifting the load of 6 kg (37.70% MVE) (P < 0.01). The EMG average amplitude when lifting at the higher speed (41.80% MVE) was significantly greater than that at the lower speed (39.19% MVE) (P < 0.05). The EMG average amplitude was increased with the increase of the trunk rotation angle without significant difference (P > 0.05). At T10, the EMG average amplitude was greater on the right side than that on the left side (50.31% MVE and 25.88% MVE respectively) while at L3, it was on the contrary (45.60% MVE on the left and 40.22% MVE on the right respectively) (P < 0.01). Multiple stepwise regression analysis showed that the load of lifting was the factor contributing most to the EMG average amplitude followed by the lifting speed. CONCLUSION: The risk factors related to work load for asymmetric lifting tasks are mainly the load and the speed of lifting. The EMG activity between the right and left side of erector spinae is different during such lifting.

Adult↗
PubMed2006

[Analysis of prognostic variables in childhood acute myeloid leukemia].

OBJECTIVE: To assess the prognostic value of the biological features and therapy-related factors in childhood acute myeloid leukemia (AML). METHODS: From January 1998 to May 2003, 75 patients with newly diagnosed AML were enrolled on the protocol AML-XH-99. Biological features at presentation [gender, age, white blood cells, platelet count, French-American-British (FAB) subtypes, cytogenetic abnormalities] and therapy-related factors [bone marrow (BM) blast cell counts at 48 h after the first induction course, complete remission (CR) rate after the first course of induction therapy] were analyzed. The probability of event-free survival (pEFS) was estimated by Kaplan-Meier analysis and the distributions of pEFS were compared using log-rank test. Chi-square analysis or Fisher exact test was used to compare differences in the distribution of presenting biological features. A Cox proportional hazards model was used to identify independent prognostic factors. RESULTS: (1) Univariate analysis of the proportion of patients attaining CR after induction indicate that FAB M(5), BM blasts >or= 0.150 at 48 h after the first induction course and no response to the first induction course were associated with lower CR rates (P = 0.001, 0.011, 0.000 respectively). Univariate analysis also demonstrated that the 5-year pEFS for patients with age < 1 year or > 10 years, platelet count < 20 x 10(9)/L, FAB M(5), hepatomegaly, BM blasts >or= 0.150 at 48 h after the first induction course and no response to the first induction course, central nervous system (CNS) leukemia was unfavorable, while the outcome of patients with cytogenetic abnormalities of t (8; 21) or t (15; 17) were better. (2) Multivariate analysis suggested that cytogenetic abnormality of t (15; 17), achieved CR after the first induction course and no CNS leukemia were independent favorable prognostic factors. CONCLUSIONS: Combined analysis of cytogenetic abnormalities with early treatment response has an important prognostic significance, and can predict outcomes.

Adolescent↗
PubMed2006

[Prognostic value of minimal residual disease in childhood B-cell acute lymphoblastic leukemia].

OBJECTIVE: To assess the prognostic value of minimal residual disease (MRD) in childhood B-cell acute lymphoblastic leukemia (ALL) after induction chemotherapy. METHODS: From September 2001 to October 2004, 102 patients with newly diagnosed B-ALL were enrolled in protocol ALL-XH-99. MRD after induction therapy, before high-dose methotrexate and early intensification as well as at 1 year and 2 year maintenance therapy was detected by multiparameter-flow-cytometry (MP-FCM). RESULTS: (1) The probability of 39-month event-free survival (EFS) for patients with a level of MRD < 10(-4), was significantly higher than for those with a higher MRD [(83.00 +/- 9.90)% vs 0.00%, P < 0.01]. (2) Univariate analysis indicated that the MRD level at achieving complete remission (CR) had no relationship with the biologic features at presentation (gender, age, white blood cells and cytogenetic abnormalities), but did with Philadelphia chromosome, the time reaching CR, ALL-XH-99 risk group and lymphoblasts in bone marrow on day 19 after induction therapy (P < 0.05). (3) Multivariate analysis suggested that MRD level after the first induction course was an independent prognostic factor (hazard ratio, 5.381; 95% CI 0.004 to 0.624; P < 0.05). CONCLUSION: The MRD level at achieving CR is one of important prognostic factor in the treatment of childhood B-cell ALL, and might be used to assess the early treatment response.

Adolescent↗