Biomedical subjects

Yi Chen

Publications and source records attributed to Yi Chen.

At least 163 records · Page 9Linked to original sources

PubMed2004

[Effect of postoperative transcatheter arterial chemoembolization on hepatocellular carcinoma patients with residual tumor].

OBJECTIVE: To evaluate the effect of postoperative adjuvant transcatheter arterial chemoembolization (TACE) on hepatocellular carcinoma (HCC) patients with residual tumor. METHODS: The patients were classified into intervention group (with adjuvant TACE) and control group (without adjuvant TACE) who were further stratified to those with high risk (patients with single tumor > 5 cm in diameter, or with multiple tumors, invasion to blood vessels), and low risk factors. Univariate analysis and Cox model were used to analyse prognostic factors. RESULTS: In low risk patients with residual tumor, the 1-, 2-, 3-, 4-year survival rate was 97.2%, 78.0%, 66.5% and 66.5% in the intervention group, and 91.2%, 81.4%, 70.3% and 54.4% in the control group, respectively. There was no statistical difference between the two groups in survival (log-rank P = 0.7667). Comparing with the control group, the 1-, 2-, 3-, 4-year survival rate was 89.5%, 73.4%, 59.2% and 53.8% in the intervention group, and 70.5%, 61.9%, 46.8% and 46.8% in the control group, respectively. Postoperative adjuvant TACE significantly prolonged the survival in high risk patients with residual tumor (P = 0.0029). Cox model revealed that the benefit of adjuvant TACE was significantly increased by the high risk factors in HCC patients with residual tumor. CONCLUSION: The beneficial effect of postoperative TACE was only observed in high risk patients with residual tumor but not in the low risk patients with residual tumor.

Adult↗

PubMed2004

[Study on the enantiomer separation of cetirizine dihydrochloride using proteinate- and amylose-based chiral stationary phase].

AIM: To study the chromatographic behavior of cetirizine dihydrochloride on the proteinate- and amylose- based chiral stationary phases so as to optimizate the chromatographic condition of its enantiomers separation. METHODS: When using amylose-based, alpha1-acid glycoprotein and ovomucoid protein chiral stationary phase, the mobile phase was hexane-isopropyl alcohol-alcohol-trifluoroacetic acid (430:45:25:1), acetonitrile-10 mmol x L(-1) phosphate buffer solution (adjusted to pH 7.0 with sodium hydroxide) (4:96) and acetonitrile-20 mmol x L(-1) KH, PO4 solution (adjusted to pH 7.0 with triethylamine) (12.7:87.3), respectively. The temperature of proteinate column was 25 degrees C. The detective wavelength was 230 nm. RESULTS: The two enantiomers could be separated on the two kinds of chiral stationary phases without derivatization and the resolution was above 2.0. The methods developed on the two kinds of chiral stationary phases are accurate, sensitive and specific. CONCLUSION: Both the proteinate- and amylose-based chiral stationary phases can be used to separate the enantiomers of cetirizine.

Amylose↗

PubMed2004

[Distribution of hepatitis B virus genotype in 5 cities of Fujian province and the clinical implications of HBV genotype].

OBJECTIVE: To study the prevalence of hepatitis B virus (HBV) genotype in 5 cities of Fujian province and the clinical implications of distinct genotypes in HBV-related liver diseases. METHODS: HBV genotype was determined by the restriction fragment length polymorphism analysis in patients with chronic HBV infection in 5 cities of Fujian province. The relationship between HBV genotype and its clinical implications was studied by multinomal logistic regression and correspondence analysis. RESULTS: Of the 431 HBV DNA positive patients detected by PCR, 275 (63.8%) belonged to HBV genotype B, 100 (23.2%) to genotype C, 51 (11.8%) to genotype D and D-mixed genotype. Genotype A, E and F were not found. Multinomal logistic regression showed that genotype B was more prevalent in Quanzhou and Sanming cities than in Fuzhou (P = 0.002, P = 0.006), and genotype B appeared significantly more common in asymptomatic carriers (ASC), chronic hepatitis B (CHB) and severe hepatitis (SH). Genotype C was most prevalent in patients with liver cirrhosis (LC) (47.0%) than in those with ASC (14.5%) and SH (14.7%) (P = 0.009, P < 0.001). The positive rate of hepatitis B e antigen was higher in patients with genotype C than in those with genotype B and genotype D (56.0% vs. 52.4%, P = 0.008, and 56.0% vs. 30.8%, P = 0.051, respectively). By correspondence analysis, genotype D and D-mixed genotype seemed to be correlated with hepatocellular carcinoma (HCC). CONCLUSIONS: (1) The major popular genotypes of HBV were B, C and D in Fujian. (2) Data of our study suggested that the geographic distribution of genotype B and C might be different in some cities of Fujian. (3) Genotype B might have a tendency to lead to SH in younger patients with chronic hepatitis B and the development of LC might be associated with genotype C among the elder patients. (4) Genotype D appeared to associate with development of HCC, which called for further study to confirm.

Adolescent↗

PubMed2004

[Apoptosis induced by hydroquinone in bone marrow mononuclear cells in vitro].

OBJECTIVE: To study the effect of hydroquinone on apoptosis of bone marrow mononuclear cells, and to evaluate the toxic effect of benzene on stem cells. METHODS: Cell morphology was observed by HT fluorescent stain method, and DNA fragments were analyzed by agarose gel electrophoresis. Anti-Annexin V FITC plus PI staining for apoptotic and necrotic rate was examined by flow cytometer. RESULTS: After adding different concentrations of hydroquinone to the cells for 6 h culture, the fluorescent intensity of nucleus increased, the color of nucleus became deep and inhomogeneous, and the chromatin was condensed and distributed around the neucleus. DNA ladder was detected in all samples. Cell apoptotic rate in different concentration of hydroquinone groups was significantly higher than that in blank control group (P < 0.05). With the increase of the concentration of hydroquinone, the apoptotic and necrotic rate also increased. The optimal concentration of hydroquinone was 50 micro mol/L. When it was >or= 75 micro mol/L, the necrotic rate increased significantly. Hydroquinone-induced apoptosis was associated with culture time at the concentration of 50 micro mol/L, and the peak apoptotic time was 10 h, then the apoptotic rate decreased and necrotic rate increased. CONCLUSION: Hydroquinone can induce apoptosis of bone marrow mononuclear cells in vitro with dose-effect and time-effect relationship.

Apoptosis↗

PubMed2004

[The protective effect of amifostine on hydroquinone-induced apoptosis in bone marrow].

OBJECTIVE: To evaluate the protective effect of amifostine on hydroquinone-induced apoptosis of bone marrow mononuclear cells in vitro. METHODS: The mononuclear cells were separated and divided into four groups: blank control, amifostine group, hydroquinone group, amifostine + hydroquinone group. The cell apoptotic rate was examined in separated group at different time point, and apoptosis was detected by HT stain, then cell morphology was observed under fluorescent microscope and DNA fragments was tested by agarose gel electrophoresis. In addition, apoptotic and necrotic rate was detected by flow cytometer. RESULTS: After 10 hour culture, DNA ladder was detected in the hydroquinone group, but not in other groups. The apoptotic rate was not significantly different between amifostine group and blank control group at different culture time (P > 0.05). After 8 - 12 hour culture, the apoptotic rate in amifostine + hydroquinone group was significantly lower than that in the group of hydroquinone alone (P < 0.01). After 18 - 48 hour culture, the necrotic rate in amifostine + hydroquinone group was lower than that in the group of hydroquinone alone (P < 0.05). CONCLUSION: Amifostine can protect cell from hydroguinone-induced bone marrow damage through inhibition on cell apoptosis, and decrease in cell necrosis.

Amifostine↗

PubMed2004

[Heat shock protein 90: novel target for cancer therapy].

The molecular chaperone heat shock protein 90 (Hsp90) is important in maintaining the conformation, stability, and function of many proteins involved in cell surviving. Hsp90 is of interest as an anticancer drug target because of its importance in maintaining the function of key oncogenic client proteins. Hsp90 inhibitors also have shown promising antitumor activity in vitro and in vivo preclinical model systems. One Hsp90 inhibitor, 17-allylamio-17- desmethoxygeldanamycin (17-AAG), is currently in clinical trial.

Animals↗

PubMed2004

Study on the pathological basis of classification of spleen deficiency in chronic gastritis.

BACKGROUND: Spleen in Traditional Chinese Medicine (TCM) is not actually the spleen in the anatomic sense designated in western medicine because its functions basically belong to the physiological category of digestive system in modern medicine, and it represents a macroscopic concept of digestion, absorption and nutrition metabolism. Spleen deficiency syndrome refers to the clinical phenomena such as hypofunction of digestion, absorption and nutrition metabolism. By integrating TCM with modern medicine, this paper is intended to explore the pathological basis of classification of spleen deficiency in chronic gastritis. METHOD: By means of optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and histochemical staining, we conducted histopathological and subcellular ultrastructural (nuclei and mitochondrial) analysis of gastric mucosa of 188 patients of spleen deficiency, and that of 42 voluntary blood donors without clinical symptoms. RESULTS: The gastric mucosa of patients with spleen Qi deficiency (SQD) and spleen yang deficiency (SyangD) could either be affected by organic lesion (type G-occurring on the basis of chronic superficial gastritis (CSG), chronic atrophic gastritis (CAG)) or unaffected (type F-chiefly belonging to functional indigestion); spleen yin deficiency (SyinD) and spleen deficiency with Qi stagnation (SDQS) both occurred on the basis of CSG and CAG; and the degree of mucosa inflammatory cells infiltration, the degree of decrease in glands propria, and the incidence of IMIIb in CSG and CAG were more serious than those of G-SQD and G-SyangD, P < 0.05 - 0.01. CONCLUSION: Spleen deficiency syndrome is likely to occur on the basis of organic lesion of gastric mucosa (disease with symptoms of both CSG or CAG and spleen deficiency symptoms), as well as on the basis of inorganic lesion of gastric mucosa (nondisease with symptoms, which is, despite spleen deficiency symptoms, there is no CSG or CAG). Besides, the clinical phenomenon of disease without symptoms (despite CSG or CAG, there is no spleen deficiency symptoms) occurres because of such factors as genetic diathesis and compensation. The lesion degree of CSG or CAG and the incidence of IMIIb of SyinD and SDQS are more serious than those CSG and CAG of G-SQD and G-SyangD.

Adult↗

PubMed2004

[Prognosis and risk factors for recurrence of small liver cancer after a single session of percutaneous radiofrequency ablation].

BACKGROUND & OBJECTIVE: As a new technique of local therapy for liver cancer, radiofrequency ablation (RFA) was widely used these years in China. This study was to evaluate the treatment efficacy of RFA on primary liver cancer (PLC), identify the risk factors of recurrence, and determine the indications of RFA for PLC. METHODS: Records of 94 primary small liver cancer patients underwent a single session of percutaneous RFA in Liver Cancer Institute/Zhongshan Hospital from Jan. 2001 to Dec. 2003 were reviewed retrospectively. Data analyses were performed using SPSS for windows Ver. 11.5 software. RESULTS: With a median follow-up of 16 months affer RFA treatment, the cumulative survival rate of 94 patients was 85.5% at 1 year, and 75.6% at 2 years. The cumulative recurrence-free survival rate was 31.3% at 1 year, and 10.4% at 2 years. The total recurrence rate was 66.0% (62/94). Log-rank test revealed that tumor with diameter of >3 cm (P< 0.05), proximity to intrahepatic vessels (P < 0.01), and subcapsular location (P< 0.05) were related to tumor recurrence,while gender, Child-pugh class, alpha fetoprotein (AFP) concentration, and combination therapy with percutaneous ethanol injection were not related to tumor recurrence. Cox regression analysis indicated that tumor proximity to intrahepatic vessels (95%CI, 2.102-7.899; P=0.000), and subcapsular location (95%CI, 1.672-6.289; P=0.001)were associated independently with recurrence after RFA treatment. Severe complications occurred in 2 cases (2.1%), including 1 case of bile duct hemorrhage, 1 case of sub-diaphragm effusion. No RFA related death and other severe complications occurred. CONCLUSIONS: RFA appears to be a safe treatment for liver cancer. Patients with tumor diameter of <or= 3 cm, no proximity to intrahepatic vessels, and subcapsular location may be the most suitable candidates for RFA.

Adult↗

PubMed2004

[Prospective randomized trial of RFA and chemotherapy for unresectable small hepatocellular carcinoma].

OBJECTIVE: To study the clinical safety and effect on local recurrence in unresectable small hepatocellular carcinoma treated by radiofrequency ablation (RFA) with and without chemotherapy through a prospective randomized trial. METHODS: Thirty-eight unresectable small hepatocellular carcinoma patients with diameter </= 3 cm were selected, of which 27 patients have been followed up for 1 year. Through a prospective randomized trial, 12 patients were in the RFA group and 15 patients in the RFA combined with systemic chemotherapy group. RFA was given image-guided. The regimen of systemic chemotherapy: EADM 50 mg on day 1, 3; CDDP 40 mg on day 1, 3 and FUDR 500 mg on day 1, 2, 3. After RFA treatment, liver function, WBC count and complications were observed on day 1, 4, 7; CT scan was performed in 1, 6, 12 months. The safety and local recurrence were analyzed. RESULTS: There was no local recurrence of the tumor in the two groups 1 month after RFA treatment. The 6- and 12-month local recurrence rates were significantly lower in the combined group than that in RFA group alone (P < 0.01). There were no severe complications in the two groups, and nor was there any significant difference in liver function and WBC count. CONCLUSION: RFA combined with systemic chemotherapy is safe, and it can reduce the local recurrence of unresectable small hepatocellular carcinoma </= 3 cm in diameter.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2004

[Distribution patterns of moss species in Shanghai city].

The mosses on the floor of 22 sites at 20 main parks and 2 chemical plants in Shanghai city were investigated and sampled. Based on 75 recorded moss species and their coverage, Two-way Indicator Species Analysis (TWINSPAN) and Detrended Correspondence Analysis (DCA) were used to analyze their distribution patterns. The results showed that the study sites could be identified as three groups. Group 1 included two chemical plants and two parks at the center of the city, with 23 moss species and the smallest total coverage of 21.29%; group 2 included part of the parks at the center of the city and surrounding areas, with 44 moss species and total coverage of 37.94%; and group 3 mainly included the parks at surrounding areas and suburbs of the city, with 49 moss species and total coverage of 49.66%. The results reflected a certain correlation of the distribution of moss species with different habitats and polluted and disturbed environments in the city.

Bryophyta↗

PubMed2004

[The emergent role of p38 MAPKs in the regulation of cell cycle].

The p38 MAPKs are members of the MAPK family. Its pathway has been traditionally associated with the stress and immune response. More recently, it has been reported that the p38 MAPKs pathway can also regulate apoptosis and some differentiation process. It can regulate cellular growth and cell cycle checkpoints in different ways depending on the cell type and the stimulus.

Animals↗

PubMed2003

Quantitative study of HIV-1 Tat peptide and TAR RNA interaction inhibited by poly(allylamine hydrochloride).

The interaction of poly(allylamine hydrochloride) (PAH) with TAR RNA has been studied by quartz crystal microbalance (QCM) cooperating with capillary electrophoresis (CE). Experimental results showed that PAH had high affinity for TAR RNA. In particular, PAH could disrupt the interaction of Tat peptide with TAR RNA, which is critical for HIV-1 virus replication. The approaches described here indicate that they are powerful for studying the binding processes of Tat peptide-TAR RNA and drug-TAR RNA, having great significance for the design of new drug.

Biosensing Techniques↗

PubMed2003

Divergent pro- and antiinflammatory roles for IL-23 and IL-12 in joint autoimmune inflammation.

Interleukin (IL) 23 is a heterodimeric cytokine composed of a p19 subunit and the p40 subunit of IL-12. IL-23 affects memory T cell and inflammatory macrophage function through engagement of a novel receptor (IL-23R) on these cells. Recent analysis of the contribution of IL-12 and IL-23 to central nervous system autoimmune inflammation demonstrated that IL-23 rather than IL-12 was the essential cytokine. Using gene-targeted mice lacking only IL-12 (p35-/-) or IL-23 (p19-/-), we show that the specific absence of IL-23 is protective, whereas loss of IL-12 exacerbates collagen-induced arthritis. IL-23 gene-targeted mice did not develop clinical signs of disease and were completely resistant to the development of joint and bone pathology. Resistance correlated with an absence of IL-17-producing CD4+ T cells despite normal induction of collagen-specific, interferon-gamma-producing T helper 1 cells. In contrast, IL-12-deficient p35-/- mice developed more IL-17-producing CD4+ T cells, as well as elevated mRNA expression of proinflammatory tumor necrosis factor, IL-1beta, IL-6, and IL-17 in affected tissues of diseased mice. The data presented here indicate that IL-23 is an essential promoter of end-stage joint autoimmune inflammation, whereas IL-12 paradoxically mediates protection from autoimmune inflammation.

Animals↗

PubMed2003

Synthesis and evaluation of chiral bicyclic proline FKBP12 ligands.

As part of our ongoing program to explore novel structural classes of FKBP12 ligands, we herein wish to report a new class of FKBP12 ligands containing chiral bicyclic proline analogues. Details of the synthetic routes, together with preliminary biological activity, will be presented.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed2003

Synthesis, molecular modeling and biological evaluation of aza-proline and aza-pipecolic derivatives as FKBP12 ligands and their in vivo neuroprotective effects.

Nonimmunosuppressant ligands, exemplified by GPI 1046 (1), for the peptidyl-prolyl isomerase FKBP12 have been found to unexpectedly possess powerful neuroprotective and neuroregenerative effects in vitro and in vivo. We have extensively explored the therapeutic utility of FKBP12 ligands based on analogues of proline and pipecolic acid. As part of our ongoing program to explore novel structural classes of FKBP12 ligands, we herein wish to report a new class of FKBP12 ligands containing aza-proline and aza-pipecolic acid analogues. Details of the synthetic studies, together with biological activity will be presented.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed2003

Synthesis and characterization of faceted hexagonal aluminum nitride nanotubes.

The synthesis of the faceted single-crystalline h-AlN nanotubes with the length of a few micrometers and diameters from 30 to 80 nm is first reported. This provides an ideal substrate for the construction of GaN-based nanoheterostructures in future nanoelectronics. The experimental results suggest the further extensive experimental and theoretical studies on the promising nonlayered nanotubular structures.

Journal Article↗

PubMed2003

3,5,6-Trisubstituted naphthostyrils as CDK2 inhibitors.

A novel class of 3,5,6-trisubstituted naphthostyril analogues was designed and synthesized to study the structure-activity relationship for inhibition of cyclin-dependent kinase 2 (CDK2). These compounds, particularly molecules with side-chain modifications providing additional hydrogen bonding capability, were demonstrated to be potent CDK2 inhibitors with cellular activities consistent with CDK2 inhibition. These molecules inhibited tumor cell proliferation and G1-S and G2-M cell-cycle progression in vitro. The X-ray crystal structure of a 2-aminoethyleneamine derivative bound to CDK2, refined to 2.5A resolution, is presented.

Antimetabolites↗

PubMed2003

Acute p38 MAPK activation decreases force development in ventricular myocytes.

Evidence suggests that p38 mitogen-activated protein kinase (MAPK) activation influences cardiac function on an acute basis. The characterization and mechanisms by which this occurs were investigated in the present study. Adult rat ventricular myocytes treated with 1 mM arsenite for 30 min had a 16-fold increase in p38 MAPK phosphorylation that was attenuated by SB-203580 (a p38 MAPK inhibitor). Extracellular signal-regulated protein kinase (ERK) and c-Jun NH2-terminal kinase (JNK) were also minimally activated, but this activation was not sensitive to SB-203580. In addition, arsenite caused a p38 MAPK-independent translocation/activation of protein phosphatase 2a (PP2a) and decrease in phosphorylation of myosin light chain 2 (LC2). Arsenite-p38 MAPK activation led to translocation of heat shock protein 27 but not alpha B-crystallin to the myofilaments. Using isolated cardiomyocytes, we determined that arsenite reduces isometric tension without a change in Ca2+ sensitivity of tension via p38 MAPK and lowers myofibrillar actomyosin Mg2+-ATPase activity in a p38 MAPK-independent manner. Thus arsenite induces a p38 MAPK-independent change in PP2a and LC2 that may account for the arsenite-dependent decrease in ATPase and a p38 MAPK-dependent modification of the myofilaments that decreases myocardial force development.

Actin Cytoskeleton↗