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Biomedical subjects

Gang Li

Publications and source records attributed to Gang Li.

242 records · Page 14Linked to original sources
PubMed2002

[Expression of leukemia inhibitory factor gene in decidua from women with habitual abortion].

To evaluate the relationship between habitual abortion of unknown etiology and expression of leukemia inhibitory factor (LIF) gene in the decidua,the expression of LIF gene in the decidua were detected in 32 cases of habitual abortion of unknown etiology (abortion group) and 36 cases of normal pregnancy (control group) by reverse transcription-polymerase chain reaction (RT-PCR). The results showed that the level of LIF mRNA expression of the decidua in abortion group was 0.512+/-0.219, significantly lower than those in the control group (1.314+/-0.457, P<0.01). The findings indicated that the low expression of LIF gene in abortion group might be one of the causes of habitual abortion. Analysis on the LIF gene expression of decidua can be used as a index for diagnosis of the habitual abortion.

English Abstract↗
PubMedDate not supplied

The molecular structures of poly(ethylene glycol)-modified nonviral gene delivery polyplexes.

Polycations can complex with DNA and form compact nanoparticles (polyplexes) to facilitate gene transfection. Recently, poly(ethylene glycol) (PEG) was incorporated in the polyplexes to improve their in vivo stability and defer body clearance. This work provided a direct look using atomic force microscopy at the molecular conformation of PEG molecules on the polyplex surfaces. Individual PEG strands were seen to extend from the compact cores and intertwined with each other to form the protective surface layer.

DNA↗
PubMedDate not supplied

IFN gamma-induced up-regulation of PD-ECGF/TP enhances the cytotoxicity of 5-fluorouracil and 5'-deoxy-5-fluorouridine in bladder cancer cells.

BACKGROUND: PD-ECGF/TP is an essential enzyme in converting 5'DFUR and 5FU to their active metabolites and can be up-regulated by some cytokines. MATERIALS AND METHODS: PD-ECGF/TP mRNA and protein expressions were determined by RT-PCR and Western blot, respectively. The cytotoxicity of 5FU, 5'DFUR or MMC against RT-4 and T24 cells was evaluated by MTS assay. The PD-ECGF/TP expressions in primary bladder cancers were also analyzed. RESULTS: Levels of PD-ECGF/TP mRNA and protein were concomitantly elevated in RT-4 and T24 cells after IFN gamma treatment. IFN gamma decreased the IC50 of 5FU and 5'DFUR in both cell lines, while it did not alter the IC50 of MMC, which is not a substrate of PD-ECGF/TP. PD-ECGF/TP expression correlated with tumor stage and grade in primary bladder cancers. CONCLUSION: IFN gamma enhances the cytotoxicity of 5FU and 5'DFUR against human bladder cancer cells through induction of PD-ECGF/TP. The results imply that an IFN gamma/5FU or IFN gamma/5'DFUR combination therapy may be applicable to clinical bladder cancers.

Adult↗
PubMedDate not supplied

The p53-stabilizing compound, CP-31398, does not enhance chemosensitivity in human melanoma cells.

BACKGROUND: Malignant melanoma is a life-threatening disease with a poor prognosis due to its capacity for rapid metastasis and resistance to radio- and chemo-therapy. A pharmacological compound, CP-31398, was recently found to be able to stabilize wild-type p53 and rescue mutant p53 to enhance its transcriptional activity and suppress tumor growth in mice. Since many chemotherapeutic drugs induce p53-dependent apoptosis, we sought to investigate if CP-31398 would enhance chemosensitivity in human melanoma cells by stabilizing p53. MATERIALS AND METHODS: Human melanoma cell lines carrying either wild-type or mutant p53 were treated with CP-31398 and anticancer drugs, and the rate of cell survival or apoptosis was determined by sulforhodamine B, propidium iodide staining and flow cytometry. The p53 protein levels were determined by Western blotting. RESULTS: A non-toxic dose of CP-31398 elevated p53 protein levels in a wild-type (MMRU) and a mutant (Sk-mel-110) p53 melanoma cell line, but did not enhance cell death induced by camptothecin. Furthermore, pretreatment with CP-31398 did not enhance camptothecin-induced apoptosis or elevate p53 protein induction. In addition, pretreatment of MMRU with CP-31398 did not enhance cell death induced by cisplatin or vincristine. CONCLUSION: CP-31398 does not enhance chemosensitivity in human melanoma cells.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Tissue-specific regulation of Apaf-1 expression by p53.

The p53 tumor suppressor is a transcription factor that regulates cell cycle and apoptosis in response to a variety of environmental stress conditions. Recent studies indicated that the apoptotic protease activating factor-1 (Apaf-1) is a direct transcriptional target of p53 in DNA damage-induced apoptosis. However, the dependence of Apaf-1 expression on p53 has not been shown in normal physiological conditions. To further investigate their relationship, we first examined Apaf-1 protein levels in seven organs including brain, heart, kidney, liver, lung, spleen, and testis of wild-type (p53+/+) and p53-deficent (p53-/-) mice by Western blot analysis. The heart and spleen of the p53-/- mice showed a reduced Apaf-1 protein expression compared with the p53+/+ controls, while other organs did not show significant difference. The results from Western blot analysis were further confirmed by immunohistochemistry. Semi-quantitative RT-PCR was then employed to determine the expression of Apaf-1 transcripts. Similarly, we detected a lower Apaf-1 mRNA level in the heart and spleen of p53-/- mice compared with the p53+/+ controls, supporting a transcriptional upregulation of Apaf-1 by p53. Taken together, these results demonstrate that p53 regulation of Apaf-1 expression is tissue-specific.

Animals↗
PubMedDate not supplied

Comparison of bladder cancer survival among Japanese, Chinese, Filipino, Hawaiian and Caucasian populations in the United States.

BACKGROUND: Racial differences for bladder cancer survival have been reported for Caucasians and African-Americans. However, the survival experience of bladder cancer patients in Asian and Pacific Islander ethnic groups in the United States have not been fully explored. The purpose of this study was to compare the bladder cancer survival rates of Japanese, Chinese, Filipinos, Hawaiians and Caucasians in the U.S. population. MATERIALS AND METHODS: The data was from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute between 1973 and 1998. Cox proportional hazard models and Kaplan-Meier's estimates were used to study differences in survival between the ethnic groups, adjusting for factors including age at diagnosis, gender, year of diagnosis, histological grade, stage, surgery type, and radiation therapy. RESULTS: The overall bladder cancer survival was 66% for Japanese patients, 64% for Chinese patients, 61% for Caucasians, 59% for Filipino patients and 52% for Hawaiian patients. Differences in bladder cancer survival rates between Japanese and Chinese populations in the United States were not observed. In the Asian population, higher relative risks and lower 5-year survival were observed with increasing age at diagnosis (p for trend<0.0001), grade (p for trend<0.0001), and stage (p for trend<0.0001). Asian women had lower survival and a higher risk of death due to bladder cancer than Asian men. CONCLUSIONS: Japanese and Chinese bladder cancer patients had higher overall survival rates than Caucasians, while Filipino and Hawaiian patients had lower survival than Caucasians.

Age Factors↗
PubMedDate not supplied

Survival rates of invasive breast cancer among ethnic Chinese women born in East Asia and the United States.

BACKGROUND: Few studies have compared the breast cancer survival rates of US born ethnic Chinese women and the survival rates of Chinese immigrants. The main purpose of this study is to explore the difference of breast cancer survival rates between the two populations and compare the survival rates to those of Caucasians born in the US. METHODS: Between 1973 and 2002, 365,215 women who had been diagnosed with primary invasive breast cancer (ICD-O-2 C500:C509) were recorded in the Surveillance, Epidemiology, and End Results (SEER) registries. Of the 316,881 breast cancer patients who were white, 180,835 (57%) were born in the United States, 20,983 (7%) were born elsewhere, and 115,063 (36%) had unknown birthplaces. Among the 3,634 breast cancer patients who were ethnically Chinese, 952 (26%) patients were born in the US, 1,356 (37%) were born in East Asia, 146 (4%) were born elsewhere, and 1,180 (33%) had unknown birthplaces. We compared the survival rates and estimated the risk ratios (RRs) by the Kaplan-Meier estimates and the Cox proportional hazards models. RESULTS: A lower 5-year overall survival rate of breast cancer was observed among Chinese women born in East Asia (0.74, 95% CI=0.72-0.77) than those born in the U.S. (0.79, 95% CI=0.76-0.81), with an adjusted hazards ratio of 1.22 (95% CI=1.06-1.40). The 5-year survival rates for SEER stage were higher among Chinese women born in the U.S. (localized: 0.90, 95% CI=0.87-0.93; regional: 0.71, 95% CI=66-0.77; distant: 0.16, 95% CI=0.06-0.25) than that among Chinese women born in East Asia (localized: 0.86, 95% CI=0.83-0.89; regional: 0.68, 95% CI=0.63-0.73; distant: 0.16, 95% CI=0.07-0.25). Higher 5-year survival rates among Chinese women born in the U.S. in comparison to Chinese women born in East Asia were also observed in different calendar years (1973-1980, 1981-1990, 1991-2002), in surgery and radiation therapy. CONCLUSIONS: Our analysis showed that among the Chinese breast cancer patients, women born in East Asia had lower 5-year survival rates than women born in the United States. SEER stage, grade, and tumor size appear to be important prognostic factors. The poor 5-year survival rates among Chinese women born in East Asia indicate potential problems of accessing medical facilities for early detection, diagnosis and treatment because of potential language and culture barriers, lower education level, as well as stress of the first generation of migrant Chinese women in the United States.

Adult↗