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Biomedical subjects

L Li

Publications and source records attributed to L Li.

At least 55 records · Page 3Linked to original sources
PubMed2006

Overexpression of Pim-1 during progression of prostatic adenocarcinoma.

AIMS: Pim-1 is a serine/threonine kinase that has been shown to play an integral role in the development of a number of human cancers, such as haematolymphoid malignancies. Recently, evidence has shown Pim-1 to be important in prostatic carcinogenesis. In order to further our understanding of its role in prostate cancer, we investigated Pim-1 expression in normal, premalignant, and malignant prostate tissue. METHODS: Using immunohistochemistry, Pim-1 expression was analysed in prostate tissue from 120 radical prostatectomy specimens. In each case, Pim-1 staining was evaluated in benign prostatic epithelium, high grade prostatic intraepithelial neoplasia (PIN), and prostatic adenocarcinoma. The number of positively staining cells was estimated, and the intensity of staining was scored on a scale of 0 to 3+. RESULTS: Pim-1 immunoreactivity was identified in 120 cases (100%) of adenocarcinoma, 120 cases (100%) of high grade PIN, and 62 cases (52%) of benign glands. The number of cells staining in benign epithelium (mean 34%) was much lower than that in high grade PIN (mean 80%; p<0.0001) or adenocarcinoma (mean, 84%; p<0.0001). There was no significant difference between high grade PIN and adenocarcinoma in the percentage of cells staining positively for Pim-1 (p = 0.34). The staining intensity for Pim-1 was significantly lower in benign prostatic epithelium than in PIN and adenocarcinoma (p<0.001). There was no statistically significant correlation between the level of Pim-1 expression and Gleason score, patient age, tumour stage, lymph node metastasis, perineural invasion, vascular invasion, surgical margin status, extraprostatic extension, or seminal vesicle invasion. CONCLUSIONS: Pim-1 expression is elevated in PIN and prostatic adenocarcinoma compared with benign prostatic epithelium. This finding suggests that upregulation of Pim-1 may play a role in prostatic neoplasia.

Adenocarcinoma↗
PubMed2006

Mapping a new genetic locus for X linked retinitis pigmentosa to Xq28.

We have defined a new genetic locus for an X linked form of retinitis pigmentosa (RP) on chromosome Xq28. We examined 15 members of a family in which RP appeared to be transmitted in an X linked manner. Ocular examinations were performed, and fundus photographs and electroretinograms were obtained for selected patients. Blood samples were obtained from all patients and an additional seven family members who were not given examinations. Visual acuity in four affected individuals ranged from 20/40 to 20/80+. Patients described the onset of night blindness and colour vision defects in the second decade of life, with the earliest at 13 years of age. Examined affected individuals had constricted visual fields and retinal findings compatible with RP. Based on full field electroretinography, cone function was more severely reduced than rod function. Female carriers had no ocular signs or symptoms and slightly reduced cone electroretinographic responses. Affected and non-affected family members were genotyped for 20 polymorphic markers on the X-chromosome spaced at 10 cM intervals. Genotyping data were analysed using GeneMapper software. Genotyping and linkage analyses identified significant linkage to markers DXS8061, DXS1073, and DXS1108 with two point LOD scores of 2.06, 2.17, and 2.20, respectively. Haplotype analysis revealed segregation of the disease phenotype with markers at Xq28.

Adolescent↗
PubMed2006

HIV and syphilis in migrant workers in eastern China.

OBJECTIVE: To measure the prevalence of HIV and syphilis in migrant and urban workers in eastern China, and to determine their knowledge and attitudes towards HIV. METHODS: A cross sectional survey involving dried blood spot testing and self completion questionnaires. Migrants and urban workers in 39 work units in two districts of Hangzhou, Zhejiang Province, were recruited. Respondents completed a questionnaire about knowledge and attitudes towards HIV. Testing for antibodies to HIV-1 and syphilis was carried out on dried blood spots using a gelatin particle agglutination technique. RESULTS: Data were obtained from 4148 migrants and 2197 urban workers. There were no HIV infections detected in either the migrant or urban populations. Syphilis was detected, but the prevalence was not significantly different between urban workers (0.68%, 95% CI: 0.35 to 1.02) and migrant workers (0.48%, 95% CI 0.26 to 0.66, p = 0.07). 36% of the migrants had migrated with a partner, and 7% had also migrated with children. Urban workers were consistently more knowledgeable than migrants about HIV, but knowledge of the major modes of transmission was good in both groups. Traditional attitudes to sexual behaviour were still pervasive in both groups and attitudes towards individuals with HIV were generally intolerant. The use of sex workers appears rare and no more common in migrants than urban workers. CONCLUSION: At present HIV is probably not spreading in the internal migrant population in eastern China. Syphilis is a problem in both the migrant and urban populations. The tendency to migrate with partners makes migrants relatively low risk for engaging in casual sex.

Adolescent↗
PubMed2006

Modelling the nucleation and chirality selection of carbon nanotubes.

The selection of chiralities of single-walled carbon nanotubes is one of the key problems of nanotube science. We suggest that the chirality-selective growth of SWNTs could be achieved using chemical vapour deposition (CVD) by controlling the type of caps that form during the nucleation stage. As the catalyst can be solid during CVD, the formation of particular caps may be favoured by an epitaxial relationship to the catalyst surface. The corresponding tubes would then grow preferentially. We show by ab-initio calculations that the formation energy of some lattice-matched caps and tubes are 1-2 eV lower than the non lattice-matched structures.

Carbon↗
PubMed2006

A polysaccharopeptide complex and a condensed tannin with antioxidant activity from dried rose (Rosa rugosa) flowers.

In this study, the fraction (P) from an aqueous extract of dried rose (Rosa rugosa) flowers was obtained by ethanol precipitation. P was chromatographed on DEAE-cellulose. The components retained on DEAE-cellulose were eluted with a linear gradient of 0-2 M NaCl solution. Two fractions, eluted at concentrations of 0.5 M NaCl and 1 M NaCl, respectively, were obtained. These two components were designated as P1 and P2, respectively. P1 was further purified using gel filtration on Sephadex G-200. P(1) yielded two peaks, and the two components were designated as P(1-a) and P(1-b), respectively. P(1-a) was a polysaccharide-peptide complex, and P(1-b) exhibited chemical properties of a condensed tannin as revealed by FTIR and NMR assay of carbohydrate and protein contents and HPLC-ESI-MS. The molecular masses of P(1-a) and P(1-b) were 150 kDa and 8 kDa, respectively. Both P(1-a) and P(1-b) possessed antioxidant activity, with the activity of P(1-b) higher than that of P(1-a). This study demonstrated that different components from rose flowers exhibited antioxidant activity.

Animals↗
PubMed2006

Compounds from rose (Rosa rugosa) flowers with human immunodeficiency virus type 1 reverse transcriptase inhibitory activity.

The aqueous extracts and ethanol precipitates of aqueous extracts of 18 medicinal herbs traditionally used in China were screened for their ability to inhibit human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT) in-vitro. Among the samples screened at a concentration of 500 microg mL-1, dried rose (Rosa rugosa) flowers showed the strongest inhibition. The ethanol precipitate of the aqueous extract of R. rugosa was processed and two components (P1 and P2) were obtained after ion exchange chromatography on DEAE-cellulose. Then, P1-a (Mr 150 kDa) and P1-b (Mr 8 kDa) were isolated from P1 by gel filtration on Sephadex G-200. They inhibited the activity of HIV-1 RT with an IC50 of 158 nM and 148.16 microg mL-1 (18.5 microM), respectively. Further structural analyses revealed that P1-a was a polysaccharide-peptide complex, and P1-b was a polymer consisting of acteoside and acteoside derivatives identified by Fourier transform infrared spectroscopy, nuclear magnetic resonance, assays of carbohydrate and protein contents and high-performance liquid chromatography electrospray ionization mass spectrometry.

Chromatography, Gel↗
PubMed2006

Biopharmaceutical therapeutics for asthma remodeling.

Current asthma therapy is aimed at controlling disease symptoms. A subset of asthma patients remains symptomatic despite optimal therapy indicating that an unmet medical need exists for these patients. Innovative therapeutics are needed to treat the unmet need in asthma and biopharmaceutical approaches may provide an opportunity for identifying these agents. It is proposed that airway remodeling contributes to asthma symptoms and this feature of disease pathology may be a target for future therapies. The current review focuses on the contribution of one feature of airway remodeling, subepithelial fibrosis, towards disease and highlights some of the mechanisms that may contribute to this feature of airway remodeling. Further, some potential molecular targets are identified for consideration for therapeutic intervention.

Animals↗
PubMed2006

Role of chemokines in severe asthma.

The severe asthma phenotype is exhibited by a subset of asthma patients whose asthma symptom is poorly controlled by current therapies. Severe asthma represents a high unmet medical need and warrants research into the mechanisms driving the underlying pathophysiology. It is hypothesized that the underlying pathology associated with severe asthma is driving the symptoms experienced by these patients, which may share common features with mild to moderate asthma or may represent a unique pathological phenotype. For the purpose of this review, the pathophysiology associated with asthma in general are described and extended to incorporate severe asthma. Chemokines may contribute towards multiple features of asthma pathophysiology and this current review focuses on the biology of chemokines pertaining to asthma pathophysiology. Chemokines are important recruiters and activators of inflammatory cells and these infiltrating cells interact with resident cells, such as fibroblasts and it is through these pathways that chemokines appear to exert multiple biological actions. Clinical trials are underway with therapeutics targeting chemokine pathways for other inflammatory diseases. It is hoped that the information generated from these studies will contribute towards furthering our understanding of chemokine biology and be applied towards targeting severe asthma.

Animals↗
PubMed2006

Expression of RHAMM/CD168 and other tumor-associated antigens in patients with B-cell chronic lymphocytic leukemia.

Antigen targeted immunotherapies might represent a novel treatment for B-cell chronic lymphocytic leukemia (B-CLL). We screened the mRNA expression of tumor-associated antigens (TAAs) from the literature (fibromodulin, survivin, OFA-iLRP, BAGE, G250, MAGE1, PRAME, proteinase, syntaxin, hTERT, WT-1) and TAAs defined previously by serological analysis of cDNA expression libraries from leukemic cells (PINCH, HSJ2, MAZ, MPP11, RHAMM/CD168, NY-Ren60). Peripheral blood mononuclear cells from 43 B-CLL patients and 20 healthy volunteers (HVs) were examined by conventional and quantitative RT-PCR. mRNA of RHAMM/CD168, fibromodulin, syntaxin and NY-Ren60 was expressed in 55-90%, and mRNA of HSJ2, MAZ and OFAiLRP was expressed in 90-100% of the patients. No expression of WT-1, hTERT, BAGE, G250, MAGE1 or survivin was observed. Low (2-20%) expression frequencies of MPP11, PINCH, PRAME and proteinase were detected. RHAMM/CD168, fibromodulin, PRAME and MPP11 showed expression in B-CLL patients, but not in HVs. Because of the exquisite tissue expression of RHAMM/CD168 and its high expression frequency in CLL patients, mixed lymphocyte peptide culture (MLPC), enzyme-linked immunosorbent spot (ELISPOT) and flow cytometry were performed for antigen specific T-cells. In MLPC, RHAMM specific responses by CD8+HLA-A2/R3tetramer+CCR7-CD45RAhigh effector T-cells were detected. RHAMM/CD168 might be a possible target for future immunotherapies in both ZAP-70(+) and ZAP-70(-) B-CLL patients.

Adult↗
PubMed2006

Production of puerarin and isoflavones in cell suspension cultures of Pueraria lobata (Willd.): effects of medium supplementation with casein hydrolysate and coconut milk.

Callus induced from leaf explants of Pueraria lobata seedlings were suspended in Gamborg B5 medium supplemented with 1 mg l(-1) 2,4-dichlorophenoxyacetic acid, 1 mg l(-1) naphthalene acetic acid, 0.5 mg l(-1) kinetin and 30 g l(-1) sucrose. The effects of coconut milk and casein hydrolysate (CH) on cell growth and yields of puerarin and isoflavones in cells suspension were studied. The contents of total isoflavones and puerarin in suspension cultures were determined by spectrophotometry and HPLC. Coconut milk (10%, filter sterilized) decreased the growth of cell cultures and the accumulation of total isoflavones, while 0.2% CH promoted the growth of cell cultures and the accumulation and release of puerarin and total isoflavones. The total yield of puerarin and isoflavones were 34% and 40.8% higher than in the control, respectively. The optimum medium for cell cultures of leaves of P. lobata seedlings was B5 liquid medium supplemented with 2% sucrose, 1.0 mg l(-1) 2,4-D, 1.0 mg l(-1) NAA, 0.5 mg l(-1) kinetin and 20 mg l(-1) CH. The procedure use is a potentially useful for the production of isoflavones.

Caseins↗
PubMed2006

Transfection of nm23-H1 increased expression of beta-Catenin, E-Cadherin and TIMP-1 and decreased the expression of MMP-2, CD44v6 and VEGF and inhibited the metastatic potential of human non-small cell lung cancer cell line L9981.

Nm23 is a metastasis suppressor gene. In this report, we transfected nm23-H1 cDNA into L9981, a human large cell lung cancer cell line with nm23 negative expression, and made a stable transfectant. L9981-nm23-H1 cells exhibited lower cells proliferation rate, more G0/G1 phase growth and an increase in apoptosis with a dramatic decreased in the tumor cells ability to metastasize. L9981-nm23-H1 cells also demonstrated a significantly reduced lymph node and pulmonary metastatic capacity in vivo when injected into the nude mice. Furthermore, we used DNA microarray analysis to explore the change in expression of the metastasis-related genes in L9981-nm23-H1 cells. We found that the expression of beta-Catenin, E-Cadherin and TIMP-1 were significantly increased while expression MMP-2, CD44v6, and VEGF was dramatically decreased in L9981-nm23-H1, as confirmed by RT-PCR and western blot. These results demonstrated that nm23-H1 can suppress the mobility and metastatic capacity of cancer cells and the molecular mechanism by which nm23-H1 suppresses tumor metastasis may be via increasing the expression of metastasis-related genes such as beta-Catenin, E-Cadherin and TIMP-1 and decreasing the expression of MMP-2, CD44V6 and VEGF.

Adenocarcinoma↗
PubMed2005

Role of defect sites and Ga polarization in the magnetism of Mn-doped GaN.

We report a study of the Mn local structure, magnetism, and Ga moments in molecular beam epitaxy grown Mn-doped GaN films. Using x-ray absorption spectroscopy and magnetic circular dichroism, we find two distinct Mn sites and a Ga moment antiparallel to Mn. First-principles calculations reproduce this phenomenology and indicate that Mn preferentially populates Ga sites neighboring N split interstitial defects. These results show that defects may strongly affect the Mn ordering and magnetism, and that the GaN valence band is polarized, providing a long-range ferromagnetic ordering mechanism for Ga1-xMnxN.

Journal Article↗
PubMed2005

A combined crossed-beam and theoretical investigation of radical-radical reaction dynamics of O(3P)+t-C4H9-->OH+iso-C4H8.

The oxidation reaction dynamics of a saturated hydrocarbon radical t-butyl leading to the isobutene +OH (X 2Pi:v"=0, 1, 2) products in the gas phase were first investigated by applying a combination of high-resolution spectroscopy in a crossed-beam configuration and ab initio calculations. By comparing the nascent OH populations with the statistical theory, the reaction mechanism at the molecular level can be described in terms of two competing dynamic pathways: the major direct abstraction process leading to the inversion of vibrational populations, and the minor short-lived addition-complex process for hot rotational distributions.

Journal Article↗
PubMed2005

Treatment of pancreatic carcinoma by adenoviral mediated gene transfer of vasostatin in mice.

BACKGROUND: Tumour growth is angiogenesis dependent and antiangiogenesis therapy may represent a promising therapeutic option. AIMS: To evaluate the inhibitory effect of vasostatin gene mediated by a replication deficient recombinant adenovirus (Ad) on human pancreatic cancer in vivo and to investigate the mechanism of action of vasostatin. METHODS: Human umbilical vein endothelium derived ECV304 cells were infected with Ad-vasostatin and Ad-lacZ, and compared with phosphate buffered saline (PBS). MTT (3,-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay was used to estimate the proliferation of ECV304 cells; tube formation assay and choriallantoic membrane assay were used to evaluate angiogenesis in vivo and in vitro. Xenografted nude mice with pancreatic cancer were established to observe in vivo tumour growth suppression. Microvessel density revealed by CD31 immunohistochemical staining was measured. RESULTS: Growth and tube formation of ECV304 cells infected with Ad-vasostatin were suppressed significantly compared with cells infected with Ad-lacZ or cells treated with PBS. Neovascularisation in the Ad-vasostatin group was less than that in the PBS and Ad-lacZ groups, based on chorioallantoic membrane results. Volumes of pancreatic tumours in the Ad-vasostatin group were significantly smaller than those in the PBS and Ad-lacZ groups at the end of the treatment period. Microvessel density in the Ad-vasostatin group was significantly lower than that in the Ad-lacZ and PBS groups. CONCLUSION: The vasostatin gene mediated by adenovirus is efficient for gene therapy for pancreatic carcinoma. Suppression of vasostatin on proliferation of vascular endothelium cells and angiogenesis may account for its effect.

Adenoviridae↗
PubMed2005

Generation of watt-level single-longitudinal-mode output from cladding-pumped short fiber lasers.

We generate as much as 1.6 W of continuous-wave 1550 nm single-longitudinal-mode output from a cladding pumped Er-Yb codoped phosphate fiber laser. This power is to our knowledge among the highest in single-longitudinal-mode fiber lasers. The narrowband fiber Bragg grating output coupler is demonstrated to be an effective element for providing the single-longitudinal-mode selection.

Journal Article↗
PubMed2005

Skin ageing: a comparison between Chinese and European populations. A pilot study.

BACKGROUND: Although limited data are available, it is commonly considered that Europeans and Asians have different skin ageing features. OBJECTIVES: The present studies have been carried out to evaluate the influence of age and sun-exposure on the main clinical signs of Asian skin ageing. METHODS: One hundred and sixty Chinese and 160 French age-matched women (age range: 20-60 years old) were clinically examined and scored by the same dermatologist. Facial wrinkles (crow's-feet, glabella and perioral wrinkles) and pigmented spots (on face and hands) were assessed in situ and standardized photographs of the face were taken. Lifelong sun-exposure was estimated from answers to a questionnaire. Comparisons were made between 10-year age groups. RESULTS: Results show that, for each facial skin area, wrinkle onset is delayed by about 10 years in Chinese women as compared to French women. Facial wrinkling rate over the years is linear in French women and not linear in Chinese women who appear to experience a fast ageing process between age 40 and 50. Pigmented spot intensity is a much more important ageing sign in Chinese women (severe for 30% of women over 40) than in French women (severe for less than 8% of women, irrespective of age). CONCLUSION: These first results underline that main skin ageing features (wrinkles, spots) progress differently in the Chinese and French women we have studied. They require to be confirmed on broad multicentre studies involving larger cohorts.

Adult↗
PubMed2005

A novel transcriptome subtraction method for the detection of differentially expressed genes in highly complex eukaryotes.

We have designed a novel transcriptome subtraction method for the genome-scale analysis of differential gene expression in highly complex eukaryotes, in which suppression subtractive hybridization (SSH) is performed first to enrich the target and, after exchange of adapters, negative subtraction chain (NSC) is then used to eliminate the remaining background. NSC evolved from differential subtraction chain (DSC). We designed novel adapters which make the subtraction system more robust. SSH and NSC were then combined to successfully detect differentially expressed genes in Solanum. The combined technique improves qualitatively upon SSH, the only commercially available transcriptome subtraction system, by detecting target genes in the middle abundance class, to which most differentially expressed genes in highly complex eukaryotes are expected to belong. The main advantage of the combined technique with SSH/NSC is its ability to isolate differentially expressed genes quickly and cost-efficiently from non-standard models, for those microarrays are unavailable.

Gene Expression Profiling↗