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Yan Li

Publications and source records attributed to Yan Li.

At least 703 records · Page 39Linked to original sources
PubMed2002

HER-2/Neu signaling and therapeutic approaches in breast cancer.

Amplification or overexpression of HER-2/neu occurs in 30% of human breast and ovarian cancers and is associated with a poor clinical outcome, including short survival and time to relapse. Recent advances in our understanding of HER-2/neu signaling pathways have significantly increased our understanding of the tumorigenesis of breast cancer and provided new targets for treating breast and ovarian tumors that overexpress HER-2/neu. In this review, we focus on the new signaling pathways mediated by HER-2/neu in breast cancer and discuss our understanding of these pathways, as they seem to be particularly important in mediating cell survival and growth under a wide variety of circumstances in breast cancer.

Journal Article↗
PubMed2002

[Effects of magnesium deficiency on senescence of Dimocarpus longana leaves].

180 days old Dimocarpus longana seedlings were grown in nutrition solution with three magnesium concentrations as 4 mmol.L-1 Mg2+ (sufficient supply), 0.4 mmol.L-1 Mg2+ (deficient supply), and Mg-free (without supply). Leaves were sampled 120 and 150 days later after treatment. With an increase in severity of Mg-deficient, the chlorophyll content, PS II activities, photosynthetic rate, protein, nucleic acid (DNA, RNA), and ZRs contents declined progressively. Whereas the content of H2O2, the rate of O2-. generation as well as the content of malondialdehyde (MDA) increased. The results suggested that magnesium deficiency had significant effect on the senescence of Dimocarpus longana leaves.

Aging↗
PubMed2002

Mcl-1 mediates cytokine deprivation induced apoptosis of human myeloma cell line XG-7.

OBJECTIVE: To investigate apoptosis in XG-7, a human myeloma cell line, induced by IL-6 deprivation and the function of three anti-apoptotic Bcl-2 proteins (Bcl-2, Bcl-kappa(L), Mcl-1) in the apoptotic process. METHODS: Apoptosis in XG-7 myeloma cells induced by IL-6 withdrawal was determined by flow cytometry with propidium iodide (PI) nuclear staining. Expressions of three Bcl-2 proteins in XG-7 cells were monitored by immunoblotting assay. RESULTS: In the absence of IL-6 for a certain time, a significant percentage of apoptiotic XG-7 cells can be observed, as well as down-regulated expression of one of the three anti-apoptotic proteins (Mcl-1) in XG-7 cells. IL-6 re-stimulation in XG-7 cells following cytokine removal up-regulated the expression of Mcl-1 and inhibited cell apoptosis. CONCLUSION: Mcl-1,instead of Bcl-2 and Bcl-kappa(L), plays an important role in IL-6 deprivation induced apoptosis in XG-7 human myeloma cells.

Apoptosis↗
PubMed2002

Effects of bicyclol on aflatoxin B1 metabolism and hepatotoxicity in rats.

AIM: To study the effect of new antihepatitis drug, bicyclol, on the metabolism and hepatotoxicity of aflatoxin B1 (AFB1) in rats. METHODS: Rats were given bicyclol 300 mg/kg/d ig for 3 d and then injected ip with AFB1 1.5 mg/kg. Liver damages were examined 16 h after ip AFB1. The in vitro metabolism of AFB1 by bicyclol-pretreated liver microsomes was investigated by HPLC assay. RESULTS: Bicyclol (300 mg/kg/d for 3 d) pretreatment provided protection against AFB1 hepatotoxicity as evidenced by the decrease of AFB1-elevated serum aminotransferase and hepatic malondialdehyde in rats. Bicyclol pretreatment slightly increased the production of the less toxic metabolite aflatoxin Q1. Bicyclol increased liver cytochrome P450 content, CYP 2B1-mediated 7-pentoxyresorufin O-dealkylase (PROD) activity, cytosolic glutathione (GSH) level, and GSH S-transferase (GST) activities. Moreover, bicyclol increased CYP 3A-mediated erythromycin-demethylase and CYP 1A-mediated 7-ethoxyresorufin O-deethylase (EROD) activities. CONCLUSION: Bicyclol protected rats against AFB1 hepatotoxicity by increasing the detoxifying metabolism of AFB1 in the liver.

Aflatoxin B1↗
PubMed2002

The expression of protein betaig-h3 inducible by transforming growth factor-beta in keratoconus and normal cornea.

OBJECTIVE: To observe the expression of a protein inducible by transforming growth factor-beta (betaig-h3) in normal cornea and keratoconus and discuss the effects of extracellular matrix on keratoconus. METHODS: In situ hybridization method was used to detect the expression of betaig-h3 in the cornea. The cDNA library was screened with human betaig-h3 cDNA probe to orient betaig-h3 mRNA in cells. The level of betaig-h3 was detected in normal cornea and keratoconus. RESULTS: betaig-h3 mainly expressed in the stroma in normal cornea and keratoconus. The positive expression decreased along with the increase of severity of the keratoconus. The negative expression was seen in severe lesions of keratoconus. The strong positive expression was seen at the interface area between the normal and the lesion of keratoconus. CONCLUSION: The decreasing of the level of betaig-h3 causes the diminution of corneal steadiness that is related to the formation of keratoconus.

Cornea↗
PubMed2002

[Effect of interleukin-1beta on aromatase activity in human osteoblast-like cells].

OBJECTIVE: To study the stimulation of interleukin (IL)-1beta and interleukin-1 receptor antagonist (IL-1ra) on aromatase activity in human osteoblast cells. METHODS: In the present study, the effect of IL-1beta and IL-1ra on aromatase (Arom) activity and mRNA expression in human osteoblast-like cells was investigated by [(3)H] water released upon the conversion of [1beta-(3)H] androstenedione to estrone and the reverse-transcription polymerase cain reaction (RT-PCR) method. The experimental group is divided into four group: G1 (IL-1beta 1 microgram/L), G2 (10 microgram/L), G3 (IL-1beta 10 microgram/L + IL-1ra 500 microgram/L) and G4 (IL-1ra 500 microgram,/L). RESULTS: The activity of G1 and G2 resulted in (4 211 +/- 348) pmol/10(6) cell.h(-1) and (4 958 +/- 231) pmol/10(6) cell.h(-1), respectively. IL-1ra neutralized the increased arom activity to control level in G3 (3 652 +/- 203) pmol/10(6) cell.h(-1). Arom mRNA expression was increased with the dose increasing of IL-1beta. CONCLUSION: These findings suggest that IL-1beta stimulates arom activity through the IL-1 receptor and addition of IL-1beta increased arom activity in a dose-dependent manner.

Aromatase↗
PubMed2002

Expression of betaig-h3 in keratoconus and normal cornea.

OBJECTIVES: To observe the expression of betaig-h3 in normal cornea and keratoconus and to elucidate the role of extracellular matrix in keratoconus. METHODS: In situ hybridization was used to detect the expression of betaig-h3 in the cornea. The cDNA library was screened with human betaig-h3 cDNA probe to locate betaig-h3 mRNA in cells. RESULTS: Expression of betaig-h3 was found mainly in the stroma of the normal cornea and keratoconus, but decrease depending on the degree of keratopathy. In some serious cases, no expression signal was detected. The strongest expression was seen at the border of the normal region and keratoconus. CONCLUSIONS: betaig-h3, the structural component of the extracellular matrix, can affect cell adhensiveness in the development of corneal fibrous interstitial organization. During the development of keratoconus, decreasing levels of betaig-h3 cause the diminution of corneal steadiness, which is related to formation of keratoconus.

Cornea↗
PubMed2002

[Aristolochic acid induced transdifferentiation and apoptosis in human tubular epithelial cells in vitro].

OBJECTIVE: To examine the possible role of aristolochic acid (AA) in transdifferentiation and apoptisis of human tubular epithelial cell line (HKC). METHODS: Cultured HKC cells were divided into five groups: serum-free (negative control) and treatment with AA at the concentrations of 5 mg/L, 10 mg/L, 20 mg/L and 40 mg/L for 48 hours, respectively. Transdifferentiation of HKC cells was observed with the following methods: detection of the expression of vimentin and cytokeratin of HKC cells with indirect immunoflourescence, determination of expression of E-cadherin and alpha-smooth muscle actin (alpha-SMA) by indirect immunohistochemical double staining, and determination of the proportion of alpha-SMA (+) HKC cells by flow cytometry. The apoptosis of HKC cells was observed with Giemsa staining, TUNEL reaction and agarose gel electrophoresis, and the ratio of apoptotic HKC cells was quantitatively analyzed by flow cytometry with propidium iodide staining. RESULTS: The expression of cytokeratin and E-cadherin reduced and that of vimentin increased in HKC cells treated with 10 mg/L of AA for 48 hours, and the expression of alpha-SMA (+) in HKC cells treated with 10 mg/L of AA (14.17 +/- 0.61)% was significantly higher than that in serum-free controls (3.57 +/- 0.52)%. Apoptosis of HKC cell treated with 40 mg/L of AA for 48 hours was 53.4%, significantly higher than that in serum-free controls (2%). Treatment with 5 mg/L of AA and 20 mg/L of AA could not induce apoptosis and transdifferentiation of cells. CONCLUSIONS: Treatment with relatively low concentration of AA (10 mg/L) might induce slight transdifferentiation in cultured HKC cells and that with higher concentration of AA (40 mg/L) for 48 hours might induce apparent apoptosis of these cells, which suggested that transdifferentiation and apoptosis of tubular epithelial cells probably played important roles in aristolochic acid-induced nephropathy.

Actins↗
PubMed2002

[Application of dendritic cells in clinical tumor therapy].

The active immunotherapy of dendritic cells is hot in tumor therapy research area. This article is a review of the source of dendritic cells, loading antigen, immunotherapy pathway, clinical application, choice of patients, and so on. It makes preparation for further research of dendritic cells.

Antigens, Neoplasm↗
PubMed2002

IL-6 inhibits apoptosis of human myeloma cell line XG-7 through activation of JAK/STAT pathway and up-regulation of Mcl-1.

BACKGROUND & OBJECTIVE: IL-6 can protect myeloma cells from apoptosis induced by various stimuli. A series of intracellular molecules might participate in this process. Our aim in this study is to investigate which anti-apoptotic Bcl-2 family proteins (Bcl-2, Bcl-XL, Mcl-1) and which signal transduction pathway(JAK/STAT, Ras/MAPK, PI-3K/Akt) can mediate the anti-apoptotic effect of IL-6 on a human myeloma cell line XG-7. METHODS: Apoptosis of XG-7 cells was analyzed by flow cytometry with propidium iodide(PI) staining of nuclei. The expression of three Bcl-2 family proteins in XG-7 cells were monitored by immunoblot assay. AG490, PD98059, and LY294002, three specific antagonists for JAK/STAT, Ras/MAPK, and PI-3K/Akt signal transduction pathways respectively, were used to determine which signal transduction pathway was responsible for the effect of IL-6 on XG-7 cells. RESULTS: IL-6 inhibited the apoptosis of XG-7 cells and up-regulated the expression of only one of the three anti-apoptotic Bcl-2 family proteins-Mcl-1. In addition, up-regulation of Mcl-1 expression induced by IL-6 was significantly inhibited in the presence of AG490, while not of PD98059 and LY294002. CONCLUSIONS: IL-6 inhibited apoptosis of XG-7 cells through up-regulation of Mcl-1 and the activation of JAK/STAT rather than Ras/MAPK nor PI-3K/Akt signal transduction pathway.

Apoptosis↗
PubMed2002

[Study on the biological activity and molecular mechanism of IFNalpha on human myeloma cell line Sko-007].

OBJECTIVE: To investigate the biological activity and molecular mechanism of interferon alpha (IFNalpha) on human myeloma cell line Sko-007. METHODS: The effect of IFNalpha on the growth of Sko-007 cells was measured by MTT assay. Cells cycle distribution and the expression of two IL-6 receptor chains (IL-6R and gp130) on Sko-007 cell surface in the absence or presence of IFNalpha were monitored by FACS analysis. The activation state of protein kinase ERK, which is involved in Ras/MAPK signal transduction pathway mediating cell survival and proliferation, and the expression of anti-apoptotic Bcl-2 family proteins-Bcl-2, Bcl-x(L) and Mcl-1 in Sko-007 cells with or without IFNalpha were determined by immunoblot assay. RESULT: IFNalpha arrested Sko-007 cell cycle progression. After stimulation with IFNalpha, an obvious increase in G(0)/G(1) phase (41.1%-->84.1%) and decrease in S phase (57.1%-->13.3%) of Sko-007 cell cycle distribution can be observed. Moreover, the proliferation of Sko-007 cells was dramatically inhibited in the presence of IFNalpha, with a maximal inhibitory rate up to 88%. In addition, the expression of gp130 on cell surface, the activation of protein kinase ERK and the expression of Bcl-2 and Bcl-x(L) were all down-regualted in IFNalpha-stimulated Sko-007 cells. CONCLUSION: The inhibitory effect of IFNalpha on the proliferation of Sko-007 cells was mediated by gp130 down-regulation, degradation of Bcl-2 family anti-apoptotic proteins and inhibition of ERK activation.

Antigens, CD↗
PubMed2002

[Drug resistance and genotyping of Klebsiella pneumoniae in lower respiratory tract infection].

OBJECTIVE: To understand the current drug resistance of Klebsiella pneumoniae in lower respiratory tract infection and the prevalence trend of extended spectrum beta-lactamase (ESBLs)-producing Klebsiella pneumoniae. METHODS: Drug resistance in 86 strains of Klebsiella pneumoniae and ESBLs-producing strains were genotyped by randomly amplified DNA polymorphisms (RAPD). RESULTS: ESBLs-producing strains accounted for 20.9% of the 86 strains, and 83.3% of the ESBLs-producing strains were from respiratory ICU. The drug resistance rate of ESBLs positive bacteria was much higher than that of ESBLs negative bacteria. ESBLs positive bacteria were resistant to both the quinolones and a minoglylosides. Eighteen ESBLs-producing strains were divided into 12 types. 3 strains had the same profile (genotype A), and 5 strains had an identical profile (genotype B), but other strains had different profiles. CONCLUSIONS: Chromosomal DNA analysis proved that certain types of ESBLs-producing Klebsiella pneumoniae were epidemic in respiratory ICU. RAPD was an economic, simple but reliable method in epidemic study.

Adolescent↗
PubMed2002

[Impact on IL-2 expression of lymphocytes in donors after G-CSF administration and its clinical significance].

In this study, to investigate the effect on expression of IL-2 in lymphocytes from bone marrow and peripheral blood of normal donors after they were mobilized by G-CSF in allo-BMT, 7 normal donors bone marrow and peripheral blood were harvested before and after G-CSF administration. The separated lymphocytes were measured by FCM after they were stained intracellularly by anti-IL-2, and their expressions of IL-2 were compared. The degree of aGVHD in patients after bone marrow transplantation was evaluated clinically, and it was compared with the status of aGVHD of 15 patients whose donors didn't receive G-CSF administration in our department, and 2 groups of patients are comparable in age, types of diseases and status of donors. The results showed that the expression of IL-2 in lymphocytes in 7 G-CSF mobilized donors decreased significantly after G-CSF administration and more severe aGVHD than grade II didn't develop in these recipient patients, and comparing with 15 patients received the bone marrow from donors who didn't receive G-CSF, the incidence of aGVHD decreased. It is suggested that the expression of IL-2 in lymphocytes was influenced by donors' G-CSF administration, and it is likely that thereby reduces the incidence of aGVHD in patients after BMT.

Adult↗
PubMed2002

[Establishment of a method for HLA-DRB genotyping in cord blood by reverse dot-blot hybridization technique].

The HLA system was discovered by virtue of the fact that it was polymorphic. The impetus for its discovery was the search for polymorphic antigens to match for transplantation, by analogy with the human red cell blood groups. The most usually DNA method of HLA typing is sequence specific oligonucleotides (SSO) and PCR sequence specific primers (SSP). SSO technique is perfectly suited for analyzing large number of samples, it is not suitable for individual or small numbers. The SSP method is ideal for typing individual samples, but it is costly and requires high capacity thermal cycles for larger numbers of samples. To set up a simple, quick, cheap and high resolution DNA method, were collected sixty-three cord blood samples from Guangzhou Cord Blood Bank, got DNA from blood by the traditional guanidine hydrochloride distillation method. Each sample was simultaneously typed by SSOP, PCR-SSP and reverse dot-blot hybridization (RDB) methods. All of typed is success. The results of three DNA methods are consistent each other. 60 HLA-DRB1 alleles could be accurately distinguished with the RDB method. Our results show that RDB method is a simple, quick, cheap and high resolution method for HLA-DRB types. It can be used in any HLA typing.

Fetal Blood↗
PubMed2002

[Cause of failure and false negative result in sentinel lymph node biopsy through vital blue injection in breast carcinoma].

OBJECTIVE: To investigate the cause of sentinel lymph node biopsy failure and false negative result in vital blue injection for breast cancer. METHODS: Eight-four female breast cancer patients were injected with vital blue to find the sentinel lymph nodes during operation. All patients were treated by the traditional radical or modified radical mastectomy with axillary dissection after sentinel node biopsy. All sentinel nodes, axillary lymph nodes and dissected specimens were submitted separately to pathological examination. RESULTS: Sentinel node was not identified at the time of operation in 11 patients, giving a failure rate of 13.1%. In 73 patients in whom sentinel nodes were identified, 32 (43.8%) revealed cancer invasion. Postoperative axillary node pathology showed cancer metastasis in all of them. Two patients who showed uninvaded sentinel nodes were demonstrated to have axillary node metastasis. These were the two false negative patients. Therefore, the prediction of axillary metastasis by the sentinel node biopsy showed a sensitivity of 90.4%, a specificity of 100% and a false negative rate of 2.7%. CONCLUSION: Failure in identifying the sentinel nodes in vital blue injection is related to the degree of mastering the technique and the method of injection. The cause of false negative result is due to an extensive primary tumor and the variation in the position of the sentinel lymph nodes.

Adult↗
PubMed2002

[Obtaining and construction of a novel gene from Schistosoma japonicum by expressed sequence tags].

OBJECTIVE: To look for new candidate vaccine molecule and characterize new genes from Schistosoma japonicum. METHODS: New genes of S. japonicum were obtained through expressed sequence tags and analyzed on line. One interest cDNA was cloned into anti-sense eukaryotic expression vector. RESULTS: An interest cDNA JAYL0230 was obtained. Analysis showed that homology existed between its deduced amino acid sequence and defender against apoptotic death 1 of human and pig, etc. Its anti-sense cDNA was cloned into eukaryotic expression vector pEGFP-N3. CONCLUSION: The combination of expressed sequence tags and bioinformatics is an effective way to find novel genes of creature. Construction of anti-sense eukaryotic vector is helpful in studying gene's function.

Amino Acid Sequence↗
PubMed2002

Effects of dimethyl diphenyl bicarboxylate on the metabolism and hepatotoxicity of aflatoxin B1 in rats.

AIM: To study the effect of antihepatitis drug, dimethyl diphenyl bicarboxylate (DDB) on the metabolism and hepatotoxicity of aflatoxin B1(AFB1) in rats. METHODS: Rats were given orally DDB 300 mg.kg-1.d-1 for 3 days and then injected intraperitioneally with AFB1 1.5 mg.kg-1. Serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were examined 16 hours after the injection of AFB1. The in vitro metabolism of AFB1 by DDB-pretreated rat liver microsome was investigated by HPLC assay. RESULTS: DDB (300 mg.kg-1) pretreatment provided significant protection against AFB1 hepatotoxicity as evidenced by the decrease of AFB1-elevated serum marker enzymes in rats. Pretreatment with DDB was shown to slightly increase the level of AFM1, the less toxic metabolite. DDB significantly increased the liver cytochrome P450 content, P450 isozyme 2B1-mediated 7-pentoxyresorufin O-dealkylase (PROD) activity, cytosolic glutahione (GSH) level and GSH S-transferase (GST) activities. In addition, DDB slightly increased P450 isozymes, 3A-mediated erythromycin-demethylase and 1A-mediated 7-ethoxyresorufin O-deethylase (EROD) activities. CONCLUSION: The results indicate that DDB protected rats against AFB1 hepatotoxicity by increasing the detoxifying metabolism of AFB1 in the liver.

Aflatoxin B1↗