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Yi Li

Publications and source records attributed to Yi Li.

At least 73 records · Page 4Linked to original sources
PubMed2006

Humoral immune responses induced by anti-idiotypic antibody fusion protein of 6B11scFv/hGM-CSF in BALB/c mice.

BACKGROUND: We have previously developed and characterized a monoclonal anti-idiotype antibody, designated 6B11, which mimics an ovarian carcinoma associated antigen OC166 - 9 and whose corresponding monoclonal antibody is COC166 - 9 (Ab1). In this study, we evaluate the humoral immune responses induced by the fusion protein 6B11 single-chain variable fragment (scFv)/human granulocyte macrophage colony-stimulating factor (hGM-CSF) and 6B11scFv in BALB/c mice. METHODS: The fusion protein 6B11scFv/hGM-CSF was constructed by fusing a recombinant single-chain variable fragment of 6B11scFv to GM-CSF. BALB/c mice were administrated by 6B11scFv/hGM-CSF and 6B11scFv, respectively. RESULTS: The fusion protein 6B11scFv/hGM-CSF retained binding to the anti-mouse F (ab) 2' and was also biologically active as measured by proliferation of human GM-CSF dependent cell TF1 in vitro. After immunization with the 6B11scFv/hGM-CSF and 6B11ScFv, BALB/c mice showed significantly enhanced Ab3 antibody responses to 6B11scFv/hGM-CSF compared with the 6B11scFv alone. The level of Ab3 was the highest after the first week and maintained for five weeks after the last immunization. Another booster was given when the Ab3 titer descended, and it would reach to the high level in a week. CONCLUSION: The fusion protein 6B11scFv/hGM-CSF can induce humoral immunity against ovarian carcinoma in vivo. We also provide the theoretical foundation for the application of the fusion protein 6B11scFv/hGM-CSF for active immunotherapy of ovarian cancer.

Animals↗
PubMed2006

[Inhibition of pulmonary fibrosis by doxycycline: an experiment with mice].

OBJECTIVE: To investigate the effect of doxycycline, an antimicrobial antibiotic inhibiting type IV collagenase, on the development of pulmonary fibrosis induced by bleomycin (BLM) in mice. METHODS: Gelatin zymography assay was used to detect the secretion of 72,000 and 92,000 type IV collagenase in HT-1080 cells and the activity of these enzymes in vitro. Experimental pulmonary fibrosis was induced by intra-tracheal administration of BLM in anesthetized mice. Total lung collagen content was determined by hydroxyproline assay. The histopathological changes of pulmonary fibrosis were evaluated by image analysis. RESULTS: The secretion of 72,000 and 92,000 type IV collagenase in HT-1080 cell was markedly inhibited by doxycycline at concentrations of 0.1 mg/ml and 0.05 mg/ml. The activity of type IV collagenase in vitro was also suppressed by doxycycline. The hydroxyproline level in the lung was decreased in mice treated with doxycycline at the dose of 100 mg/kg, down to 34.7% of that of the BLM model group. As shown by image analysis, the extensiveness of fibrotic lesions, the thickness of interalveolar septa, and the accumulation of nucleated cells were decreased in doxycycline treated group in comparison with BLM model group. CONCLUSION: This study provides evidence that doxycycline shows inhibitory effect on BLM induced pulmonary fibrosis.

Animals↗
PubMed2006

A salt-free zero-charged aqueous onion-phase enhances the solubility of fullerene C60 in water.

An onion-phase (multilamellar vesicular phase or Lalpha-phase) was prepared from salt-free zero-charged cationic and anionic (catanionic) surfactant mixtures of tetradecyltrimethylammonium hydroxide (TTAOH)/lauric acid (LA)/H2O. The H+ and OH- counterions form water (TTAOH + LA --> TTAL + H2O), leaving the solution salt free. The onion-phase solution has novel properties including low conductivity, low osmotic pressure and unscreened electrostatic repulsions between cationic and anionic surfactants because of the absence of salt. The spherical multilamellar vesicles have an average 250 nm radius as measured by freeze-fracture transmission electron microscopy (FF-TEM) and the maximum interlayer distance, i.e., the thickness of the hydrophobic bilayer and the water layer, was calculated to be around 52 nm by small-angle X-ray scattering (SAXS). Extremely hydrophobic C60 fullerene can be solubilized in this salt-free zero-charged aqueous onion-phase. As a typical result, 0.588 mg.mL(-1) (approximately 0.82 mmol.L(-1)) C60 has been successfully solubilized into a 50 mmol.L(-1) catanionic surfactant onion-phase aqueous solution. The weight ratio of fullerene to TTAL is calculated to be around 1:40. Solubilization of C60 in the salt-free catanionic onion-phase solution was investigated by using different sample preparation routes, and a variety of techniques were used to characterize these vesicular systems with or without encapsulated C60. The onion-phase solution changed color from slightly bluish to yellow or brown after C60 was solubilized. 1H and 13C NMR measurements indicated that the C60 molecules are located in the hydrophobic layers, i.e., in the central positions [omega-CH3 and delta-(CH2)x] of the hydrophobic layers of the TTAL onion-phase. Salt-free zero-charged catanionic vesicular aqueous solutions are good candidates for enhancing the solubility of C60 in aqueous solutions and may broaden the functionality of fullerenes to new potential applications in biology, medicine, and materials. Hopefully, our method can also be extended to solubilize functionalized carbon nanotubes in aqueous solutions.

Fullerenes↗
PubMed2006

Identification and characterization of compounds that potentiate NT-3-mediated Trk receptor activity.

Neurotrophins are a family of secreted proteins that play an important role in the development, differentiation, and survival of neurons. Studies also suggest that aberrant neurotrophin signaling may play a role in processes underlying disease states such as schizophrenia, Alzheimer's disease, and depression. Whereas the development of agents that selectively stimulate neurotrophin signaling has proven to be difficult, compounds have been identified that potentiate neurotrophin 3 (NT-3)-mediated activation of trk A. In the present studies, we extend those initial observations to identify compounds that also potentiate NT-3-mediated activation of trk B. Compound potentiation of NT-3 was observed using several readouts of transfected and endogenous trk receptor activity, including trk receptor phosphorylation, mitogen-activated protein kinase phosphorylation, reporter assay activity (beta-lactamase and luciferase), cell survival and neurite extension assays. Studies using chimeric trk receptors demonstrated that the extracellular domain is essential for compound potentiation and rule out interaction with intracellular signaling molecules as a mechanism of compound activity. Thus, the present studies demonstrate that trk B receptor activity can be potentiated by small-molecule compounds via the extracellular domain of the receptor and provide reagents for further evaluating the role of NT-3-mediated trk A and trk B activity in vivo.

Animals↗
PubMed2006

Examining the need for neck dissection in the era of chemoradiation therapy for advanced head and neck cancer.

OBJECTIVES: To (1) determine clinical factors that predict pathologic complete response (pCR) on neck dissection after sequential chemoradiotherapy (SCRT) for advanced head and neck cancer and (2) compare survival parameters between those who underwent neck dissection and those who did not among those patients with a clinical complete response (cCR) in the neck after SCRT, thus assessing the benefit of neck dissection in patients with a cCR in the neck. DESIGN: Retrospective review with a mean follow-up of 3.5 years. SETTING: Regional cancer center. PATIENTS: The study population comprised 55 patients undergoing SCRT for advanced head and neck cancer with N2 or N3 neck disease. Three patients developed progressive disease and were excluded, and 28 patients underwent neck dissection. INTERVENTIONS: Patients were assessed by physical examination and radiographically after SCRT. MAIN OUTCOME MEASURES: Physical examination and radiographic assessments of residual neck disease were compared with pathologic findings in those patients who underwent neck dissection. Survival comparisons were made between patients with a cCR in the neck who underwent neck dissection and those who did not. RESULTS: Of 28 patients who underwent neck dissection, 8 had persistent pathologically positive nodal disease: 5 (45%) of 11 had N3 and 3 (18%) of 17 had N2 disease. Individual clinical neck assessments after SCRT were fairly predictive of a negative pathologic finding at neck dissection. The negative predictive values were physical examination (75%), computed tomography or magnetic resonance imaging (71%), and positron emission tomography (75%). However, when physical examination, imaging studies, and positron emission tomography all indicated a complete response, this accurately predicted a pCR on neck dissection. There appeared to be no improvement in survival parameters when a neck dissection was performed on patients with a cCR in the neck. CONCLUSIONS: Patients with N3 disease are at high risk for residual neck metastasis after SCRT. Patients with N2 disease can be assessed with physical examination, imaging studies, and positron emission tomography. If these all indicate a cCR, then neck dissection is likely not needed. Neck dissection did not appear to further improve survival parameters for patients with a cCR in the neck.

Adult↗
PubMed2006

Rate of pathologic complete responses to docetaxel, cisplatin, and fluorouracil induction chemotherapy in patients with squamous cell carcinoma of the head and neck.

OBJECTIVE: To report the rate of pathological complete response after induction chemotherapy with the docetaxel, cisplatin, and fluorouracil (TPF) combination. DESIGN: Retrospective cohort analysis. SETTING: Tertiary care academic cancer center, between June 1999 and May 2004. PATIENTS: Seventy-two patients with newly diagnosed squamous cell carcinoma of the head and neck; 68 (95%) of the patients had stage IV, locally advanced disease. INTERVENTIONS: Three cycles of induction chemotherapy followed by a biopsy of the primary site. All patients subsequently underwent chemotherapy with 3 cycles of TPF. MAIN OUTCOME MEASURE: Rate of pathological complete response at the primary site after induction chemotherapy with 3 cycles of TPF. RESULTS: Biopsy results were negative for cancer in 64 patients (89%) and positive in 8 patients (11%). The median follow-up was 2 years. In the positive biopsy result group, 2 (25%) of 8 patients died of disease vs 3 (4%) of 64 patients in the negative biopsy result group. Twenty-nine neck dissections were performed; results were positive in 7 patients (all alive with no evidence of disease) and negative in 22 patients (21 alive with no evidence of disease). The overall 2- and 5-year progression-free survival is currently projected at 85% and 85%, respectively; the overall 2- and 5-year survival, at 95% and 90%, respectively. Importantly, T4 presentation did not predict a positive biopsy result at the primary site or a positive neck dissection result (P = .60 and P = .56, respectively). N3 presentation (12 patients) did not predict a positive biopsy result at the primary site (P = .87) but did correlate with positive neck dissection results in 6 of 12 patients (P<.001). CONCLUSIONS: Induction chemotherapy with the TPF regimen results in a high pathological complete response rate (89%). This rate is higher than with the cisplatin plus fluorouracil combination therapy, which was reported to be between 25% and 50% in previous studies. Chemoradiotherapy is currently an accepted standard of care, but induction chemotherapy continues to be investigated. Based on recent phase 3 trial results and the data presented herein, we propose that the 3-drug combination be used as the new platform when administering induction chemotherapy.

Adult↗
PubMed2006

Phase II trial of taxol in salivary gland malignancies (E1394): a trial of the Eastern Cooperative Oncology Group.

BACKGROUND: Malignant tumors of the salivary glands make up approximately 5% of head and neck cancers. The Eastern Cooperative Oncology Group (ECOG) initiated a phase II evaluation of paclitaxel in patients with locally recurrent or metastatic salivary gland malignancies. METHODS: Chemo-naive patients with histologically confirmed recurrent or metastatic carcinoma of salivary gland origin (mucoepidermoid, adenocarcinoma, or adenoid cystic) were eligible. Patients were treated with paclitaxel, 200 mg/m(2) IV, every 21 days for a minimum of four cycles. RESULTS: Forty-five patients were treated. Eight partial responses were seen among the 31 patients with mucoepidermoid or adenocarcinoma histologic findings for a response rate of 26%. No responses were seen in the adenoid cystic carcinoma group. No significant difference in overall survival was found among these three histologic subgroups. CONCLUSION: Paclitaxel demonstrates moderate activity in salivary gland tumors of mucoepidermoid and adenocarcinoma histology. The poor response rate in adenoid cystic carcinoma is consistent with prior reports in this chemoresistant histologic subtype.

Adenocarcinoma↗
PubMed2006

Bone marrow stromal cells induce BMP2/4 production in oxygen-glucose-deprived astrocytes, which promotes an astrocytic phenotype in adult subventricular progenitor cells.

Bone morphogenetic proteins (BMPs) affect cell proliferation and differentiation. Astrocytes in ischemic brain are highly responsive to bone marrow stromal cell (BMSC) treatment. We investigated the effects of BMSCs on astrocytes cultured under oxygen- and glucose-deprived conditions, which in part simulate in vivo stroke conditions, to test the hypothesis that BMSCs alter astrocytic expression of BMPs which may contribute to neurological functional recovery of stroke. Quantitative real-time RT-PCR showed that the expression of BMP2/4 mRNAs decreased within ischemic astrocytes, In contrast, BMP2/4 mRNA was significantly increased after cocultured with BMSCs. Western blotting also confirmed this increase at the protein level in the medium of ischemic astrocytes after coculture with BMSCs. As a source of neural stem and progenitor cells, cultured subventricular zone (SVZ) neurospheres exposed to medium obtained from ischemic astrocytes cocultured with BMSCs were significantly enriched in cells expressing the astrocytic marker glial fibrillary acidic protein (GFAP), but not at the expense of beta-III-tubulin-positive SVZ neuroblasts. The expression of BMP2/4 subsequently increased the phosphorylation of downstream effector Smad1 and the expression of notch signal pathway-induced protein Hes1 in cultured SVZ neurospheres. BMP antagonist Noggin blocked the elevation of phosphorylated Smad1 and the expression of Hes1 as well as reducing the percentage of astrocytic SVZ progenitor cells. Our results indicate that BMSCs increase BMP2/4 expression in ischemic astrocytes. These changes enhance subventricular progenitor cell gliogenesis by activating relevant signaling pathways. BMSC-stimulated signaling of endogenous astrocytes may alter the ischemic environment, promoting remodeling of brain and hence, improve functional recovery after stroke.

Animals↗
PubMed2006

Results of a union-based smoking cessation intervention for apprentice iron workers (United States).

OBJECTIVE: Blue-collar workers are more likely to smoke, smoke more heavily, and have less success in quitting compared to white-collar workers, and this occupational gap is growing over time. Effective smoking cessation interventions among blue-collar workers are needed to address growing class-based disparities. METHODS: We used a pre-post study design to test feasibility and effect size of a smoking cessation trial in a union apprenticeship training program for iron workers (n = 337). The 4-month intervention drew upon a health promotion-health protection model for smoking cessation among blue-collar workers. We conducted pairwise analyses to assess pre-post intervention differences in 7-day point prevalence smoking abstinence measured 1 month after intervention was completed. Additional secondary outcomes, including smoking frequency, intensity, intention and self-efficacy to quit, were also assessed. RESULTS: Baseline smoking prevalence was 41%. We observed a 19.4% post-intervention quit rate among baseline smokers. There were statistically significant positive changes pre- and post-intervention in intention to quit smoking, self-efficacy to quit, and a reduction in the number of days smoked. Participation in pro-active intervention components was associated with a three-fold (OR = 3.0, 1.15, 7.83) increase in the likelihood of quitting. Overall, participation in intervention components was low. CONCLUSIONS: Labor union apprenticeship programs represent a promising venue for smoking cessation interventions, particularly those that draw upon a health promotion-health protection model.

Adult↗
PubMed2006

Directed evolution of human T cell receptor CDR2 residues by phage display dramatically enhances affinity for cognate peptide-MHC without increasing apparent cross-reactivity.

The mammalian alpha/beta T cell receptor (TCR) repertoire plays a pivotal role in adaptive immunity by recognizing short, processed, peptide antigens bound in the context of a highly diverse family of cell-surface major histocompatibility complexes (pMHCs). Despite the extensive TCR-MHC interaction surface, peptide-independent cross-reactivity of native TCRs is generally avoided through cell-mediated selection of molecules with low inherent affinity for MHC. Here we show that, contrary to expectations, the germ line-encoded complementarity determining regions (CDRs) of human TCRs, namely the CDR2s, which appear to contact only the MHC surface and not the bound peptide, can be engineered to yield soluble low nanomolar affinity ligands that retain a surprisingly high degree of specificity for the cognate pMHC target. Structural investigation of one such CDR2 mutant implicates shape complementarity of the mutant CDR2 contact interfaces as being a key determinant of the increased affinity. Our results suggest that manipulation of germ line CDR2 loops may provide a useful route to the production of high-affinity TCRs with therapeutic and diagnostic potential.

Antigens↗
PubMed2006

Delayed embryo development in the ARABIDOPSIS TREHALOSE-6-PHOSPHATE SYNTHASE 1 mutant is associated with altered cell wall structure, decreased cell division and starch accumulation.

The tps1 mutant, which is disrupted in the TREHALOSE-6-PHOSPHATE SYNTHASE 1 gene, has been previously characterized as a recessive embryo lethal. tps1 embryos do not develop past late torpedo or early cotyledon stage. We report here that at the ultrastructural, biochemical, and transcriptional levels tps1 exhibits many features typically associated with the maturation phase. The appearance of storage reserve transcripts and organelles follows the same temporal pattern in tps1 and wild-type (WT) embryos in the same silique as does accumulation of storage lipid and protein. The mutant plastids accumulate large starch granules that persist until the end of seed development, in contrast with WT plastids where starch accumulation is transient. The transcriptome of tps1 embryos shows a coordinate downregulation of genes involved in starch and sucrose degradation. Interestingly, genes involved in lipid mobilization and gluconeogenesis are induced in tps1 embryos. The cell walls of tps1 embryos show a remarkable degree of thickening at the ultrastructural level and immunodetection of cell wall components shows that altered deposition of pectins accounts for this altered morphology. Consistent with this at the transcriptome level, genes involved in sugar nucleotide and pectin metabolism are altered in the mutant. The frequency of cell division in tps1 embryos is half that of the wild type at the heart and torpedo stages. These results suggest that TPS1 may play a major role in coordinating cell wall biosynthesis and cell division with cellular metabolism during embryo development.

Arabidopsis↗
PubMed2006

Expression of baculovirus late and very late genes depends on LEF-4, a component of the viral RNA polymerase whose guanyltransferase function is essential.

Baculovirus lef-4 encodes one subunit of the viral RNA polymerase. Here, we demonstrate the essential nature of LEF-4 by RNA interference and bacmid knockout technology. Silencing of LEF-4 in wild-type virus-infected cells suppressed expression of structural genes, while early expression was unaffected, demonstrating its essential role in late gene expression. After transfection of insect cells with lef-4 mutant bacmid, no viral progeny was produced, further defining its central role in infection. Cotransfection with wild-type lef-4 plasmid restored normal replication, but plasmid encoding a guanyltransferase-deficient version failed to rescue. These results emphasize the importance of the mRNA capping function of LEF-4.

Animals↗
PubMed2006

Protein kinase Czeta and glucose uptake.

Protein kinase Czeta (PKCzeta) is a member of the PKC family, serving downstream of insulin receptor and phosphatidylinositol (PI) 3-kinase. Many evidences suggest that PKCzeta plays a very important role in activating glucose transport response. Not only insulin but also glucose and exercise can activate PKCzeta through diverse pathways. PKCzeta activation and activity are impaired with insulin resistance in muscle and adipose tissues of type II diabetes individuals, but heightened in liver tissue, wherein it also increases lipid synthesis mediated by SREBP-1c (sterol-regulatory element-binding protein). Many studies have focused on linkage between PKCzeta and GLUT4 translocation and activation. Exploring the molecular mechanisms and pathways by which PKCzeta mediates glucose transport will highlight the insulin-signaling pathway.

Animals↗
PubMed2006

Wnt-1 is dominant over neu in specifying mammary tumor expression profiles.

Wnt-1 and Neu collaborate to induce mammary tumors in bitransgenic mice carrying both MMTV-Wnt-1 and MMTV-Neu. In this report, gene expression profiles were determined for tumors from these bitransgenic mice, and compared with expression profiles of tumors from mice singly transgenic for MMTV-Wnt-1 or MMTV-Neu. While very different from tumors arising in MMTV-Neu transgenic mice, tumors from these bitransgenic mice were found not to have identifiable differences from tumors from MMTV-Wnt-1 transgenic mice, using clustering and multidimensional scaling analyses (unsupervised and supervised), One-way Analysis of Variance (ANOVA), and two sample t test (the later two of which were combined with false discovery rate computation). These observations suggest that Wnt-1 is dominant over Neu in specifying mammary tumor expression profiles.

Animals↗
PubMed2006

Comprehensive analysis of the ATM, CHEK2 and ERBB2 genes in relation to breast tumour characteristics and survival: a population-based case-control and follow-up study.

BACKGROUND: Mutations in the ataxia-telangiectasia mutated (ATM) and checkpoint kinase 2 (CHEK2) genes and amplification of the v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 (ERBB2) gene have been suggested to have an important role in breast cancer aetiology. However, whether common variation in these genes has a role in the development of breast cancer or breast cancer survival in humans is still not clear. METHODS: We performed a comprehensive haplotype analysis of the ATM, CHEK2 and ERBB2 genes in a Swedish population-based study, which included 1,579 breast cancer cases and 1,516 controls. We followed the cases for 8.5 years, on average, and retrieved information on the date and cause of death during that period from the nationwide Swedish causes of death registry. We selected seven haplotype-tagging SNPs (tagSNPs) in the ATM gene, six tagSNPs in the CHEK2 gene and seven tagSNPs in the ERBB2 gene that predicted both haplotypic and single locus variations in the respective genes with R2 values > or = 0.8. These tagSNPs were genotyped in the complete set of cases and controls. We computed expected haplotype dosages of the tagSNP haplotypes and included the dosages as explanatory variables in Cox proportional hazards or logistic regression models. RESULTS: We found no association between any genetic variation in the ATM, CHEK2 or ERBB2 genes and breast cancer survival or the risk of developing tumours with certain characteristics. CONCLUSION: Our results indicate that common variants in the ATM, CHEK2 or ERBB2 genes are not involved in modifying breast cancer survival or the risk of tumour-characteristic-defined breast cancer.

Aged↗
PubMed2006

Glucuronidation of trans-resveratrol by human liver and intestinal microsomes and UGT isoforms.

Resveratrol (trans-resveratrol, trans-3,5,4'-trihydroxystilbene) is a naturally occurring stilbene analogue found in high concentrations in red wine. There is considerable research interest to determine the therapeutic potential of resveratrol, as it has been shown to have tumour inhibitory and antioxidant properties. This study was performed to investigate the glucuronidation of resveratrol and possible drug interactions via glucuronidation. Two glucuronide conjugates, resveratrol 3-O-glucuronide and resveratrol 4'-O-glucuronide, were formed by human liver and intestinal microsomes. UGT1A1 and UGT1A9 were predominantly responsible for the formation of the 3-O-glucuronide (Km = 149 microM) and 4'-O-glucuronide (Km = 365 microM), respectively. The glucuronide conjugates were formed at higher levels (up to 10-fold) by intestinal rather than liver microsomes. Resveratrol was co-incubated with substrates of UGT1A1 (bilirubin and 7-ethyl-10-hydroxycamptothecin (SN-38)) and UGT1A9 (7-hydroxytrifluoromethyl coumarin (7-HFC)). No major changes were noted in bilirubin glucuronidation in the presence of resveratrol. Resveratrol significantly inhibited the glucuronidation of SN-38 (Ki = 6.2 +/- 2.1 microM) and 7-HFC (Ki = 0.6 +/- 0.2 microM). Hence, resveratrol has the potential to inhibit the glucuronidation of concomitantly administered therapeutic drugs or dietary components that are substrates of UGT1A1 and UGT1A9.

Animals↗