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Biomedical subjects

Yan Chen

Publications and source records attributed to Yan Chen.

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

[Effect of health education on the lung function and life quality in patients with stable chronic obstructive pulmonary diseases].

OBJECTIVE: To evaluate the effect of health education on the symptoms, lung function and life quality in patients with stable chronic obstructive pulmonary diseases (COPD). METHODS: Eighty-two patients were assigned into 2 groups randomly: The treatment group (n = 43) accepted health education for 6 months and the control group (n = 39) did not. Before and after the 6 months, we observed the number of smokers, Borg score, inhale treatment, times of acute episode, SGRQ score, lung function, and the therapeutic effect in the two groups. RESULTS: Six months later, the ratio of smokers in the treatment group was 13.95%, much lower than that in the control group (35.90%, P = 0.021); the Borg score of the treatment group decreased from 4.86 +/- 1.21 to 3.38 +/- 0.94 (P =0.000), but there was no difference in the control group; the ratios of accepted inhale treatment in the treatment group and the control group were 100% (43/43) and 20.51 % (8/39) respectively (P = 0.000), and the accuracy rates were 100% (43/43 ) in the treatment group and 12. 82% (5/39) in the control group (P =0. 000); the times of acute episode in the treatment group was 1.51 +/- 1.53, much lower than that in the control group (4.46 +/- 5.17, P = 0. 000); the indexes of lung function before and after the 6 months between the two groups had no significant difference. The total score, the symptom section score, the activity section score, and the impact section score of SGRQ after the 6 months of health education were much lower than those of 6 months before, and those in the control group had no significant difference. CONCLUSION: Six months of the health education can decrease the ratio of smokers and the times of acute episode, and to improve the life quality of patients with stable COPD.

Adult↗
PubMed2006

[Study on mismatch repair genes of chronic myeloid leukemia].

OBJECTIVE: To investigate the expression and regulation mechanism of mismatch repair (MMR) genes in chronic myeloid leukemia (CML). METHODS: Expression of MMR genes hMSH2, hMSH3, hMSH6, hMLH1 and hPMS2 mRNAs in 62 CML patients and K562 cell line were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Expression of bcr-abl mRNA and MMR genes mRNA were detected by RT-PCR in 26 CML patients with allogeneic peripheral blood stem cell transplantation (allo-PBSCT) and 4 CML patients on imatinib treatment. Expression of bcr-abl mRNA was detected by RT-PCR and tyrosine phosphorylation of BCR-ABL fusion protein by Western blot. RESULTS: Expression of hMSH2, hMSH3 and hMLH1 mRNA was significantly lower in CML and K562 cells than in normal control (P < 0.05). In 26 CML with allo-PBSCT and 4 CML patients on imatinib treatment, expressions of hMSH2, hMSH3 and hMLH1 mRNA was enhanced while expression of bcr-abl mRNA decreased. In CML MNC after imatinib treatment and in K562 cells, expression of hMSH2, hMSH3 and hMLH1 mRNA was enhanced while tyrosine phosphorylation of BCR-ABL fusion protein decreased. CONCLUSION: Expressions of hMSH2, hMSH3 and hMLH1 mRNA were down-regulated by bcr-abl fusion gene.

Adult↗
PubMed2006

[Foodborne diseases occurred in 2003--report of the National Foodborne Diseases Surveillance System, China].

OBJECTIVE: To study the foodborne disease outbreaks in the areas covered by National Foodborne Disease Surveillance System. METHODS: Total 13 provinces were included in the surveillance system, and the foodborne disease data in 2003 was collected. RESULTS: A total of 802 outbreaks of foodborne disease were reported. These outbreaks caused a reported 17462 persons to become ill. Among outbreaks for which the etiology was determined, bacterial pathogens caused the largest percentage of outbreaks (46.4%) and the largest percentage of cases (60.4%). Vibrio parahaemolyticus (40.1%) accounted for the largest number of outbreaks and cases. Chemical agents caused 24.1% of outbreaks and 13.9% of cases. CONCLUSION: More work needs to be done to improve the foodborne disease surveillance system.

China↗
PubMed2006

[Biological characteristics of hyperleukocytic acute leukemia].

The study was to investigate the biological characteristics of hyperleucocyte acute leukemia (HAL) and its clinical significance. Immunophenotyping was performed in 48 HAL patients and 73 NHAL patients by three-color flow cytometry analysis using CD45/SSC gating, meanwhile the cytogenetic analysis was performed in 74 patients. The results showed that as compared with NHAL group, HAL group had lower proportion of eryth-lineage in bone marrow (P < 0.05); in AML, the CD14 expression of HAL group was apparently higher than that of NHAL group (P < 0.05); in ALL, HAL group had higher expression of CD8 and lower expression of CD22, cCD79a compared with NHAL group (P < 0.05); the two groups had no significant difference in expression of special lineage antigens and overlapping lineage antigens (P > 0.05). The CR rate of HAL group was lower than that of NHAL group. It is concluded that bone marrow inhibition of HAL group is more severe than that of NHAL group. In AML, monocytic leukemia is easier to become into HAL than other leukemias. In ALL, T-lineage antigens of HAL group are more easily expressed than those of NHAL group; the leukemia cells of HAL group are naiver than those of NHAL group, meanwhile the prognosis of HAL is poor.

Adolescent↗
PubMed2006

[Trehalose loading red blood cells and freeze-drying preservation].

This study was aimed to investigate the feasibility of cryopreserving red blood cells (RBCs) by loading with trehalose and to evaluate the effect of trehalose on lyophilized RBCs. Based on the thermal properties of RBC plasma membrane, the RBCs were incubated in 0.8 mol/L trehalose solution at 37 degrees C for 7 hours, and RBCs incubated in phosphate-buffered saline were used as control. The morphology of RBCs was observed by light and scanning electron microscopy, the hemolysis rate of loaded RBCs was detected by using cyanohemoglobin kit, the intracellular trehalose levels were assayed by sulfate anthrone method, the intracellular ATP and 2, 3-DPG levels were determined by bioluminescence assay and 2, 3-DPG kit respectively, meanwhile the deformation and osmotic fragility of RBCs were measured. The results showed that the intracellular trehalose concentration was 36.56 +/- 7.95 mmol/L, the electronical microscopic images of trehalose-loaded RBCs showed the membrane integrity, the hemolysis rate in trehalose-loaded RBCs was 15.663 +/- 3.848%, while hemolysis rate in controlled RBC was 5.03 +/- 1.85% (P < 0.05). Maximum index of deformation in trehalose-loaded RBC was 0.0289 +/- 0.00738, while maximum index of deformation in control group was 0.1200 +/- 0.0121 (P < 0.05), The level of ATP in trehalose-loaded RBC was 2.67 +/- 0.54 micromol/gHb, while the level of ATP in control group was 5.22 +/- 1.10 micromol/gHb (P > 0.05). Osmotic fragility data showed that trehalose exerted osmotic protection on RBC. During loading period the level of 2, 3-DPG in trehalose-loaded RBC was maintained close to the level in control. When trehalose-loaded RBCs were lyophilized and rehydrated, the recovery rate of hemoglobin was about 46.44 +/- 4.14% and that in control was 8.33 +/- 2.34% (P < 0.001). The recovery rate of hemoglobin of trehalose-loaded RBC was higher than that of control. It is concluded that trehalose can be integrated in the membrane of RBC in lyophilization state, maintain the integrity of RBC membrane, and significantly enhance the recovery rate of hemoglobin of cryopreserved RBCs. Cryopreserving RBCs by loading with trehalose is feasible.

Blood Preservation↗
PubMed2006

[Association between polymorphisms of XPD gene and susceptibility to chronic benzene poisoning].

OBJECTIVE: To explore the relationship between genetic polymorphisms of XPD gene and susceptibility to chronic benzene poisoning. METHODS: A case control study was conducted. Eighty patients diagnosed with chronic benzene poisoning and 62 workers occupationally exposed to benzene who were engaged in the same working time and job title as patients were investigated. PCR-RFLP was used for detecting the single nucleotide polymorphisms (SNPs) on codon156, codon312 and codon751 of XPD gene. RESULTS: There was a 2.903 times (95% CI: 1.054 - 7.959, P = 0.039 2) increased risk of chronic benzene poisoning in the subjects carrying XPD 751Gln variant allele compared with those carrying XPD 751Lys/Lys genotype, after adjusted for sex, length of service, smoking and drinking status. CONCLUSION: The subjects with XPD 751Gln variant allele are more susceptive to benzene.

Alleles↗
PubMed2006

[Screen of media for insect cells (HzAm1) growth and its adaptation to low serum culture].

Insect cell-baculovirus system is a useful tool for both insecticidal virus production and the expression of medically useful foreign genes. Serum-free culture or low serum culture for insect cells is essential and significant. Media for the growth of insect cells HzAm1 from three kinds of commercial media TC-100,GRACE and IPL-41 with 10% serum were investigated and screened. The result shows that medium TC-100 is the most suitable medium for the growth of cells HzAm1. Adaptation of insect cells HzAm1 to cultures in medium TC-100 with serum reduction from 10% to 1% was carried out as cultures were supplemented with lactalbumin hydrolysate and yeastolate etc. Growth of insect cells HzAml in medium TC-100 with serum 1%, lactalbumin hydrolysate and yeastolate was well.

Adaptation, Physiological↗
PubMed2006

[Epigenetic modification in human leukemia].

Epigenetic modification, which involve DNA methylation, RNA-associated silencing and histone modification, is implicated in cell proliferation, differentiation, survival, apoptosis and malignant transformation. Some leukemogenesis has been shown to be aberrance of epigenetic modification. This paper discussed the potential causes of some of leukemias correlating with the methylation of cell cycle regulation genes, small interference RNA and modification abnormality of histone after translation. The study on epigenetic modification abnormality of leukemia cells provides a new strategy for treatment of leukemia.

DNA Methylation↗
PubMed2006

[Prognostic analysis of chronic myeloid leukemia with Cox model and the Sokal, Hasford score].

This study was aimed to analyze the prognostic factors of the patients with chronic myeloid leukemia (CML). Survival curve and survival rate of 204 patients with CML were estimated with Kaplan-Meier method and Logrank respectively. Univariate and multivariate analysis of prognostic factors carried out by Cox's regression model. The Sokal and Hasford score were used to discriminate the relative risk of Hu and IFN group. The results showed that among the 204 patients, the median survival time was 50 (32-65) months, and 5 year survival rate was 32.3% (95% CI, 23.7%-42.6%). The median survival times of IFN and Hu group were 56 (41-67) and 41 (19-56) months, and 5 year survival rates were 45.4% (95% CI, 37.5%-54.2%) and 26.8% (95% CI, 21.6%-33.3%) (P < 0.001) respectively. From the Cox stepwise regression model, Ph chromosome negative, high LDH, low Hct, percentage of peripheral blood basophils > or = 10%, marrow blasts + promyelocytes > or = 10% and presence of nucleated RBCs was associated with poor prognosis, and the treatment also played an important role in CML. According to the Sokal score, the high, intermediate and low risk rates of Hu group were 72.9%, 21.5% and 5.6%, the median survival time reached 34 (23-49) months, 43 (32-58) and 50 (38-62) months respectively; while censored by the Hasford score, the high, intermediate and low risk rates of IFN group were 17.6%, 25.1% and 57.3% respectively, the median survival time was 44 (33-57), 56 (45-70) and 66 (52-76) months respectively. It is concluded that Ph chromosome, concentration of LDH, percentage of Hct, peripheral blood basophils, marrow blasts, promyelocytes, presence of nucleated RBCs and treatment are the most important prognostic factors for CML. The Sokal score can not discriminate the relative risk of Hu group well, while the Hasford score can discriminate the relative risk of IFN group.

Adolescent↗
PubMed2006

[Study on degradation kinetics or potassium dehydroandrographolidi succinas].

OBJECTIVE: To investigate the hydrolytic degradation of the kinetic characteristics of Potassium Dehydroandrographolidi Succinas (DAS-K) in aqueous solution. METHODS: The HPLC method was used to determine the degradation kinetic parameters of DAS-K aqueous solution at different initial concentration, different pH, different ionic strength. various temperatures and in different buffer solutions. RESULTS: DAS-K hydrolytic degradation followed first-order kinetics as measured by HPLC. From pH 8, the hydrolytic degradation rate of DAS-K markedly increased with pH. DAS-K was unstable in alkaline pH solution. The species of buffer solutions seem to have different impact on the catalytic process. The ionic strength did not have significant effect on the stability of the drug. According to the Arrhenius plot, the dependence of the decomposition on temperature was a determining factor, the activation energy was estimated to be 95.68 KJ/mol in phosphate buffer solution at pH 8 and temperature from 60 to 90 degrees C. CONCLUSION: It was found that the hydrolytic degradation of DAS-K complied with first-order kinetics. The rate of hydrolytic degradation of DAS-K depended on the pH of solution, the buffer concentration, the buffer species and the temperature. Especially, pH value was an important factor in determining the rate of the hydrolytic degradation of the drug.

Diterpenes↗
PubMed2006

[Effects of triptolide and TNF-alpha on the expression of VEGF in Raji cells and on angiogenesis in ECV304 cells].

In order to study the relation of antitumour mechanisms of triptolide with neovascularization, the effect of triptolide and tumour necrosis factor (TNF)-alpha on the expression of vascular endothelial growth factor (VEGF) in Raji cell lines and their effect on angiogenesis in human umbilical vein endothelial cells (HUVECs)-derived cell line ECV304 were investigated. The inhibitory rate of cells treated by triptolide detected by MTT; the ELISA was employed to study the VEGF content secreted by Raji cell lines; angiogenesis was tested by network formation of endothelial cells on Matrigel, and the mRNA level of VEGF was measured by RT-PCR. The results showed that treatment of Raji cells with triptolide resulted in significantly enhanced antiproliferative effects in dose- and time-dependent manner. The content of VEGF secreted by Raji cells was increased by TNF-alpha and was suppressed by triptolide (P < 0.01). The mRNA expressions of VEGF(165) and VEGF(121) (containing 165 and 121 amino acid residues, respectively) could be detected in all fractions. TNF-alpha augmented the expression of VEGF(165) and VEGF(121) mRNA when triptolide reduced the expression (P < 0.01). No network and cord were formed in control and triptolide group. There was tube formation on matrigel in the supernatants of Raji culture group and the supernatants groups treated by VEGF and TNF-alpha in Raji cell. It is concluded that the expressions of VEGF in Raji cells are increased by TNF-alpha and suppressed by triptolide. VEGF and TNF-alpha induce angiogenesis and triptolide inhibits angiogenesis in ECV304 cells.

Angiogenesis Inhibitors↗
PubMed2006

[Clinical characteristics and immunophenotype of aged patients with acute leukemia].

In order to analyze the clinical characteristics and biological features of acute leukemia in elderly, 104 acute leukemia patients in elderly were retrospectively analyzed and compared with 71 acute leukemia patients below 60 years old. The results showed that: (1) the proportion of AML in the aged group (73%) was higher than that in the young group (54.9%), and the difference was statistically significant (P < 0.05), but AML (M3) was absent in the aged group; (2) the median of bone marrow blast cell in the aged group was significantly lower than that in the young group (P < 0.05); (3) in AML, the frequently of CD14 expression was higher in the aged group (18.8%) than that in the young group (2.6%), while the expression frequencies of CD15 (37.5%), CD117 (62.5%), and CD38 (59.4%) were respectively lower in the aged group than that in the young group which were (69.2%) for CD15, (89.7%) for CD17, and (84.6%) for CD38 respectively, and the difference was also statistically significant (P < 0.05). (4) CD19 was most frequently expressed in ALL of the aged group and the positive rate was 100%; (5) there was no significant difference in expression of special lineage antigens and overlapping lineage antigens between the aged group and the young group (P > 0.05); (6) the expression frequency of unfavorable karyotypes in the aged group was higher than that in the young group, and the difference was statistically very significant (P < 0.01); (7) the complete remission rate (CR rate) in the aged group was 42.9%, 2-year survival rate in the aged group was 5.4%, and treatment-related mortality rate in the aged group was 26.8%, while the CR rate in the young group was 76.6%, the difference was statistically significant (P < 0.05). It is concluded that the expression frequency of CD14 associated with unfavorable prognosis is higher in the aged group than that in the young group, while the expression frequency of CD15 associated with favorable prognosis is lower in the aged group than that in the young group. The expression frequency of unfavorable karyotypes in the aged group is higher than that in the young group. The CR rate of acute leukemia in elderly is low, thus the patients in elderly often have unfavorable prognosis.

Adult↗
PubMed2005

Effects of TNF-alpha and curcumin on the expression of VEGF in Raji and U937 cells and on angiogenesis in ECV304 cells.

BACKGROUND: To better understand the possibilities of antiangiogenic tumor therapy and to assess possible side effects, we investigated the effect of tumour necrosis factor (TNF)-alpha and curcumin on the expression of vascular endothelial growth factor (VEGF) in U937 and Raji cell lines and their effect on angiogenesis in a human umbilical vein endothelial cell (HUVECs)-derived cell line (ECV304), and also the relationship between Notch1 and VEGF. The aim of this study was to elucidate potential mechanisms controlling tumor neovascularization. METHODS: VEGF secreted by U937 and Raji cell lines was determined by ELISA. Angiogenesis was tested by network formation of endothelial cells on Matrigel. Levels of VEGF mRNA in U937 and Raji cells and Notch1 mRNA levels in EV304 cells were determined by RT-PCR. RESULTS: Secretion of VEGF by U937 and Raji cells was increased by TNF-alpha treatment and suppressed by curcumin (P < 0.01). The mRNA expression of VEGF165 and VEGF121 (containing 165 and 121 amino acid residues, respectively) were detected in any fractions. TNF-alpha augmented the expression of VEGF165 and VEGF121 mRNA and curcumin reduced the expression (P < 0.01). No networks or cords formed in control and curcumin groups. There was tube formation on matrigel in the supernatants of the Raji culture group and the supernatants groups treated by VEGF group and TNF-alpha in Raji cell. Notch1 mRNA was detected but there was no significant change in the VEGF group compared with control (P > 0.05). CONCLUSIONS: Expressions of VEGF mRNA in U937 and Raji cells were increased by TNF-alpha and suppressed by curcumin. VEGF and TNF-alpha can induce angiogenesis, and curcumin can inhibit angiogenesis in ECV304 cells.

Cell Line↗
PubMed2005

Prevalence of MDS subtypes in Shanghai, China: a comparison of the World Health Organization and French American British classifications.

The prevalence of subtypes of the myelodysplastic syndromes (MDS) was determined in a prospective series of 176 patients presenting at 28 Shanghai hospitals. Diagnosis was established in a single laboratory, analyzing morphologic, immunophenotypic, and cytogenetic data, using the World Health Organization (WHO) revised classification and directly compared to the French American British (FAB) criteria. The median age at diagnosis for all cases was 53 years. There was a striking increase in the prevalence of RCMD in younger patients relative to other subtypes (WHO). The overall frequency of clonal cytogenetic abnormalities was 26.5% (WHO) and 31% (FAB). The most frequently encountered lesions were trisomy 8, del(20)q, del(7q), and del(5q). These results are consistent with previously reported age-dependent differences in MDS and a decreased frequency of del(5q) abnormalities between China and the West. These results also indicate that multilineage dysplasia is a prominent feature in MDS developing in younger individuals in Shanghai and suggest distinguishing between RCMD and RA may be important in the design of studies to further understand regional differences in subtype prevalence and to elucidate the pathogenesis of this complex and multifactorial disease.

Adolescent↗
PubMed2005

Arsenite induces a cell stress-response gene, RTP801, through reactive oxygen species and transcription factors Elk-1 and CCAAT/enhancer-binding protein.

RTP801 is a newly discovered stress-response gene that is induced by hypoxia and other cell stress signals. Arsenic is a heavy metal that is linked to carcinogenesis in humans. Here, we investigated the mechanism by which arsenic induces RTP801 transcription. In HaCaT human keratinocytes, arsenite was able to induce a rapid rise in the RTP801 mRNA level. Correspondingly, arsenite treatment was capable of stimulating a 2.5 kb human RTP801 promoter. Such a stimulatory effect was inhibited by co-expression of superoxide dismutase or glutathione peroxidase, and was abrogated by N-acetylcysteine, implying that ROS (reactive oxygen species) were involved in transcriptional regulation of the RTP801 gene. A series of deletion studies with the promoter revealed a critical arsenic-responsive region between -1057 and -981 bp of the promoter. Point mutations of the putative Elk-1 site and the C/EBP (CCAAT/enhancer-binding protein) site within this region were able to reduce the stimulatory effect of arsenite, indicating that Elk-1 and C/EBP are involved in transcriptional regulation of the RTP801 gene by arsenite. Furthermore, a gel mobility-shift assay demonstrated that arsenite was able to mount the rapid formation of a protein complex that bound the arsenic-responsive region as well as the C/EBP-containing sequence. The arsenite stimulation on RTP801 transcription was partly mediated by the ERK (extracellular-signal-regulated kinase) pathway, since the effect of RTP801 was inhibited by a selective ERK inhibitor. In addition, overexpression of Elk-1 and C/EBPbeta was able to elevate the promoter activity. Therefore these studies indicate that RTP801 is a transcriptional target of arsenic in human keratinocytes, and that arsenic and ROS production are linked to Elk-1 and C/EBP in the transcriptional control.

Apoptosis↗