Biomedical subjects

Qian Huang

Publications and source records attributed to Qian Huang.

At least 37 records · Page 2Linked to original sources

PubMed2005

[In vitro transdifferentiation of adult human retinal pigment epithelium cells to neuro-like cells induced by blocking VEGF expression].

OBJECTIVE: To investigate the effects of blocking VEGF expression on the retinal pigment epithelium (RPE) in vitro. METHODS: RPE was transfected with plasmid encoding anti-sense of VEGF by lipofectin. RPE clones with stable expression of anti-sense of VEGF were screened by neomycin (G418). The changes of RPE and the level of VEGF secreted by RPE were observed by immunofluorescence immunohistochemical staining, Elisa and inverted-microscope. RESULTS: Transdifferentiation of cultured adult human retinal pigment epithelium cells to neurons was induced by blocking VEGF expression. The transdifferentiation was a direct phenotypic change from RPE cell to neurons without cell differentiation. The transdifferentiated neurons showed up-regulated expression of VEGF receptor 2 (Flk-1) and expressed several markers of retinal ganglion cell, including Thy1.1 and neurofilament. CONCLUSION: Blocking of VEGF expression and up-regulation of Flk-1 can induce transdifferetiation of adult human retinal pigment epithelium cells into ganglion cells.

Adult↗

PubMed2005

[Protective effects of transplantation of hCNTF-transfected cell line on axotomy-induced degeneration of retinal ganglion cells].

OBJECTIVE: To investigate the protective effects of transplantation of cell line stably expressing and secreting human ciliary neurotrophic factor (hCNTF) on the degeneration of retinal ganglion cells (RGCs) after optic nerve transection. METHODS: Plasmid encoding hCNTF was transfected into human lung fibroblast (HLF) cell line, then the stably transfected clones were selected with methopterin. In adult SD rats, RGCs were labeled with retrograde axonal tracer fluorogold (FG) injected to their targets including dorsal lateral geniculate nuclei (dLGN) and superior colliculi (SC). Seven days later, the optic nerve was transected alone or in combination with transplantation of HLF cells. Five, 14, 17, 21 and 28 days after axotomy, the retinas were mounted and examined under fluorescence microscope to observe the RGCs. RESULTS: Compared to the controls, the density of RGC in axotomy group decreased by 67.44% and 82.73% on the 14th and 28th day, respectively. In the eyes with hCNTF-transfected HLF cells transplantation, RGC density was higher than that of the axotomy group on the 5th, 17th, 21st day after axotomy (P < 0.05). On the 5th day, the morphology of RGC in the hCNTF group remained the same as the controls, whereas the morphology of RGC in the axotomy alone group began to change. CONCLUSIONS: hCNTF administered at the time of optic nerve transection can protect RGC from degeneration, increasing the numbers of surviving RGCs and delaying the death of RGCs.

Animals↗

PubMed2005

[Surgery of osteomas of the sinuses].

OBJECTIVE: To explore the different surgical choices for treating osteomas of the sinuses. To summarize the management and characteristics of each surgical operation. METHOD: A retrospective evaluation of thirty-one patients with osteomas of the sinuses from June 1993 to December 2001 was presented. Fourteen patients were operated through a lateral rhinotomy with radical operation in 13 cases. Eight patients were operated by nasal endoscopic management, osteomas were completely removed. Eight osteomas were removed with a coronal incision. One case underwent Caldwell-Luc surgery. The clinical symptoms, location of osteomas, and surgical procedures were analyzed. RESULT: The complications of brain spinal fistula occurred in 2 cases, but they were treated in the same time of operations. One patient had a single blindness after the operation. Twenty-eight cases were followed-up for 1 to 9 years with an average of three point seven years. Twenty-six patients had no recurrence, two cases lived with the remains of osteomas. CONCLUSION: The choice of surgical operations on osteomas of the sinuses was mainly decided by the location and size of osteomas, and the anatomic characteristics of sinuses, in the meanwhile, the organ function, the cosmetology, and the doctors experience were taken into account.

Adolescent↗

PubMed2005

[Analysis of angiogenesis associated factors of retinoblastoma cell line and tumor tissues].

OBJECTIVE: To investigate the factors regulating angiogenesis of retinoblastoma. METHODS: Cultured retinoblastoma cells from HXO-Rb-44 cell lines were inoculated subcutaneously into the leg of nude-mice. Experimental retinoblastoma was studied by immunohistochemistry staining for the expression of angiogenesis factors (VEGF-A, VEGF-C, VEGF-D and bFGF), vascular endothelial cell membrane receptor tyrosine kinases (Flt-1, Flt-4, Flk-1, Tie-2 and FGFR), transcription regulated factor, Hif-1, matrix metalloproteinase (MMP-2, MMP-7 and MMP-9) and tissue inhibitor of metalloproteinase (TIMP-1 and TIMP-2). RESULTS: There were plenty of capillaries and small vessels in the retinoblastoma. Some retinoblastoma cells expressed Hif-1 and most cells expressed VEGF at a high level, especially VEGF-D. Flt-1, Flt-4 and FGFR were found in vascular endothelial cells in the retinoblastoma. Three matrix metalloproteinases were positive and two tissue inhibitors of metalloproteinases were negative in the retinoblastoma. CONCLUSIONS: Down-regulated TIMP and up-regulated MMP and VEGF signal transduction play an important role in the occurrence of angiogenesis in the retinoblastoma. This could be considered as the target of retinoblastoma treatment.

Animals↗

PubMed2005

[Relationship between allergic factors and chronic sinusitis with or without nasal polyps].

OBJECTIVE: To explore the effects of allergic factors in chronic sinusitis and nasal polyps. METHOD: Eosinophil in nasal secretions and allergen skin test of 1882 patients with chronic sinusitis and nasal polyps were examined before endoscopic sinus surgery. The occurrence ratios of allergic symptoms and syndromes were analyzed and compared with clinical stages of chronic sinusitis and nasal polyps. RESULTS: (1) Allergic symptoms (or syndromes) were presented in 60.4% (1137 cases) of patients in different degrees, 25.3% (477 cases) patients suffered from allergic rhinitis, 2.1% (39 cases) patients had asthma; (2) The morbidities of allergic rhinitis and asthma, the positive rates of eosinophil and allergen skin test, the occurrence rates of allergic symptoms were rising with the clinical stages in type I and type II, especially in type II stage 3; (3) There were 42.2% (795 cases) positive patients in allergen skin test, among them, 94% were sensitive to perennial allergens; (4) Allergic symptoms appeared in 26.3% (495 cases) patients, among them, 99.8% attacked perennially; (5) Of all patients, there were 38.9% (732 cases) had been operated cases before, among them 38.3% (280 cases) with allergy rhinitis. In chronic sinusitis with allergy rhinitis patients, 58.7% (477 cases) were suffered from operation. CONCLUSIONS: Allergic factors,especially perennial allergic rhinitis, are relative to clinical stages of chronic sinusitis and nasal polyps. Allergic rhinitis is an important factors in recurrence.

Adolescent↗

PubMed2005

Cytokine and immuno-gene therapy for solid tumors.

Despite recent progress in our understanding of cancer biology and in many areas of cancer treatment, the success rate for cancer therapy remains dismal. Immunotherapy for cancer has long been an exciting field for many cancer researchers due to the possibility to mobilize the body's own immune system to eradicate cancer not only locally but also systemically. Since its initial discovery, cytokine-based immunotherapy has been vigorously and extensively investigated for cancer treatment due to the perception of it as a relatively easily purifiable, injectable form of cancer treatment agent. However, so far most cytokine-based therapy trials have fallen short of expectations. One of main obstacles is the difficulty to achieve therapeutically relevant dosage in patients without generating excessive normal tissue toxicity. The emergence of novel gene therapy approach to deliver therapeutic cytokine to tumors locally generated great excitement since it has the potential of generating sustained high local concentration of immunostimulatory cytokine without raising the systemic levels of the cytokines, which is responsible for most of the observed toxicity. In this review, we will attempt to provide an overview of the field and discuss some of the problems associated with cytokine-based immuno-gene therapy and potential solutions.

Adenoviridae↗

PubMed2005

[Modified intranasal endoscopic Lothrop procedure].

OBJECTIVE: To report the experience of modified endoscopic Lothrop procedure (MELP) in 6 cases and to discuss the operative technique and indications. METHODS: Six patients (four males and 2 females) aged from 6 to 63 years old with frontal sinus diseases were enrolled in this study, including 3 cases of frontal mucocele, 1 case of recurrent hemangioma, 1 case of recurrent inverted papilloma and 1 case of osteoma. All patients were underwent intranasal modified Lothrop procedure with the guidance of nasal endoscope. The image-guided navigational system was used for the location of frontal sinus in 2 cases. RESULTS: The operation was successful in all 6 patients without any operative and postoperative complications. The average operation time was 3.2 h. The endoscopic examination demonstrated the wide communicational frontal sinus openings and well epithelization after 6-40 months follow-up. The patients were asymptomatic up to now and no recurrence was found. CONCLUSIONS: The modified intranasal endoscopic Lothrop procedure is an ideal surgical approach for recalcitrant frontal sinus disorders on the basis of proper selection of surgical equipments and patients by the experienced surgeon.

Adolescent↗

PubMed2005

[Endoscopic surgery for nasal septal perforation].

OBJECTIVE: To describe the relevant factors of endoscopic surgery in patients with nasal septal perforation. METHODS: Twenty-three patients with nasal septal perforation were treated under nasal endoscope. Four kinds of reconstruction materials were used to accomplish the closure of perforation: residual osseous septum or temporalis fascia, inverting septal mucoperichondrial flap, autologous connective tissue insert overlaid with mucous flaps and turbinate flap. The reconstructed septum was packed by moist dressing with silicone or plastic splints. RESULTS: Seven patients underwent direct closure. Inverting flap repair for five cases, shifting flap closure for ten cases, and repair with turbinate flap in one case. During the follow-up ranging from four weeks to seven months, the successful reconstruction was achieved in 19 cases (82.6%). The problems in the remaining four cases were: mucosal flap displacement, fascia flap shrank and so caused reperforation, two perforations present with only the larger one repaired, the mucosal flap was smaller in size than the perforation. CONCLUSIONS: Intranasal endoscopic reconstruction surgery is a reasonable management for nasal septal perforation.

Endoscopy↗

PubMed2005

[Achieving pathogenesis understanding of ocular diseases by deciphering the underlying molecular pathways].

The field of ophthalmology research has experienced a revolution since the 1970's, when molecular biology techniques were gradually and widely adopted. Many of the developments generated impact that went far beyond the field of ophthalmology. A classic case was the identification and characterization of the Retinoblastoma susceptibility gene (Rb), whose impact went far beyond the rare and obscure disease, as it provides key evidence for the concept of tumor suppressor gene and the "two hit" theory of tumor formation. The identification of scores of genes involved in retinitis pigmentosum (pigmentosa), on the other hand, show cases the complexity of multi-factorial diseases. Ophthalmology researchers in China have been quick in integrating these novel tools into their research. However, the field still lags behind in the effective use of these technologies to carry out in-depth inquiries into key disease mechanisms. The advent of "omics" technologies heralded a new era in biomedical research that allows for the global and rapid survey of genetic and biochemical profiles. Effective integration of these novel technologies into ophthalmology research will have far-reaching impact for the whole field.

Biotechnology↗

PubMed2005

[Tumor targeting gene transfer mediated by electroporation for growth suppression of retinoblastoma in vivo].

OBJECTIVE: To explore the effects and mechanisms of electroporation on the therapy of transplanted retinoblastoma tumor (RB) by transferring the expressive plasmids of sFlk-1 and ExTek. METHODS: The effects and mechanisms of sFlk-1 and ExTek on RB is validated both in vitro and in vivo. In vitro, pCI-sFlk-1 was transfected into HEK293 (human embryonic kidney 293) cells with DMRIE-C Reagent, and its supernatant was collected 24 h later to mix with RPMI-1640 medium as 1:1, 2:1 and 3:1. RB cells were cultured in the mixed medium and the cell growth curve were analyzed 6 days later. The suspension of 1 x 10(7) RB cells were inoculated in 40 nude mice subcutaneously. The nude mice with RB were divided into 2 groups. The experimental group was treated with transfer of pCI-sFlk-1 (15 microg) and pCI-ExTek (15 microg) by electroporation once a week, while the control group was treated with physiological saline solution. After 3 weeks' therapy, the animals were observed for one more week. During this period the tumors were measured to draw the growth curve of the tumors and to calculate the anti-tumor rate. The vessel endothelium were tagged with smooth muscle actin (SMA) by immunohistochemical methods to inspect the micro vessel density (MVD) of the tumors. Moreover, the expression of vascular endothelial growth factor (VEGF) and its receptor Flk-1 of the tumors was confirmed by immunohistochemical staining. RESULTS: sFlk-1 exhibited no inhibiting effects on the growth of RB cells in vitro, while sFlk-1 combined with ExTek restrained the growth of the transplanted tumors obviously in vivo, and the anti-growth rate is 80.04%. The MVD of the experimental group is 26.69 +/- 2.95, which is evidently lower than that of the control group (44.51 +/- 6.11). The difference between these 2 groups was statistically significant (P < 0.05). As to the expression of VEGF, there was no significant difference between these 2 groups, while the expression of Flk-1 of the experimental group was much stronger than that of the control group. CONCLUSION: Transfer the expressive plasmids of sFlk-1 and ExTek by electroporation in vivo restrained the growth of the transplanted RB tumor, and the effect is due to the inhibition of angiogenesis process.

Animals↗

PubMed2004

Identification of a small molecule nonpeptide active site beta-secretase inhibitor that displays a nontraditional binding mode for aspartyl proteases.

A small molecule nonpeptide inhibitor of beta-secretase has been developed, and its binding has been defined through crystallographic determination of the enzyme-inhibitor complex. The molecule is shown to bind to the catalytic aspartate residues in an unprecedented manner in the field of aspartyl protease inhibition. Additionally, the complex reveals a heretofore unknown S(3) subpocket that is created by the inhibitor. This structure has served an important role in the design of newer beta-secretase inhibitors.

Acetamides↗

PubMed2004

Enhancement of hypoxia-induced tumor cell death in vitro and radiation therapy in vivo by use of small interfering RNA targeted to hypoxia-inducible factor-1alpha.

Hypoxia-inducible factor-1alpha (HIF-1alpha) is an important transcriptional factor that is activated when mammalian cells experience hypoxia, a tumor microenvironmental condition that plays pivotal roles in tumor progression and treatment. In this study, we examined the idea of down-regulating HIF-1alpha in tumor cells for therapeutic gain. We show that the expression levels of HIF-1alpha can be significantly attenuated by use of the recently established small interfering RNA technology in combination with adenovirus-mediated gene transfer. Down-regulation of the HIF-1alpha protein enhanced hypoxia-mediated tumor cell apoptosis in vitro. Subcutaneous tumor growth was also prevented from cells with attenuated HIF-1alpha expression. In addition, intratumoral injection of adenovirus encoding the HIF-1alpha-targeted small interfering RNA had a small but significant effect on tumor growth when combined with ionizing radiation. Therefore, our results provide proof of HIF-1alpha as an effective target for anticancer therapy. They also suggest that an adenovirus-based small interfering RNA gene transfer approach may be a potentially effective adjuvant strategy for cancer treatment.

Apoptosis↗

PubMed2004

GW112, a novel antiapoptotic protein that promotes tumor growth.

GW112 is a novel gene that has little homology to other known genes. It is overexpressed in a number of human tumor types, especially in those of the digestive system. We show here that GW112 is associated with GRIM-19, a protein known to be involved in regulating cellular apoptosis. Functionally, GW112 could significantly attenuate the ability of GRIM19 to mediate retinoic acid-IFN-beta-mediated cellular apoptosis and apoptosis-related gene expression. In addition, GW112 demonstrated strong antiapoptotic effects in tumor cells treated with other stress exposures such as hydrogen peroxide. Finally, forced overexpression of GW112 in murine prostate tumor cells led to more rapid tumor formation in a syngeneic host. Taken together, our data suggest that GW112 is an important regulator of cell death that plays important roles in tumor cell survival and tumor growth.

Apoptosis↗

PubMed2004

A role for Toll-like receptor 4 in dendritic cell activation and cytolytic CD8+ T cell differentiation in response to a recombinant heat shock fusion protein.

Recombinant heat shock fusion proteins (Hsfp) injected into mice without added adjuvants can stimulate production of CD8 cytolytic T cells. Because initiation of productive immune responses generally requires dendritic cell (DC) activation, the question arises as to whether the Hsfp can activate DC independently of contaminating LPS. Using microarray analyses of DC from LPS-insensitive mice having a point mutation in Toll-like receptor 4 (Tlr4) (C3H/HeJ), or lacking Tlr4 (B10/ScNCr), we show here that unlike a LPS standard, Hsfp activated DC from HeJ mice almost as well as DC from wild-type mice. Consistent with the microarray analysis, the Hsfp's ability to activate DC was not eliminated by polymyxin B but was destroyed by proteinase K. The Hsfp did not, however, stimulate DC from mice lacking Tlr4. In vivo the CD8 T cell response to the Hsfp in mice lacking Tlr4 was impaired: the responding CD8 cells initially proliferated vigorously but their development into cytolytic effector cells was diminished. Overall, the results indicate that this Hsfp can activate DC independently of LPS but still requires Tlr4 for an optimal CD8 T cell response.

Animals↗

PubMed2004

A novel conditionally replicative adenovirus vector targeting telomerase-positive tumor cells.

PURPOSE: To develop a novel conditionally replicative adenovirus vector that targets telomerase-positive cancer cells. EXPERIMENTAL DESIGN: A telomerase gene-derived promoter was used to control the expression of the E1a gene so that the E1a gene is only expressed in telomerase-positive tumor cells. In addition, a reporter gene was also engineered into the vector so that its infection and replication can be monitored easily. RESULTS: A novel recombinant adenovirus vector that could selectively replicate in telomerase-positive cancer cells was made successfully. This vector showed active replication in a panel of cancer cells and minimal replication in normal human fibroblast or epithelial cells. The recombinant vector could effectively lyse various cultured tumor cells even at very low multiplicity of infection. The replication efficiency in tumor cells is over 10(3)-fold more than normal fibroblast and epithelial cells. In s.c. tumor models, the newly developed telomerase-selective adenovirus vectors exhibited significantly more virus replication and reporter gene expression. CONCLUSIONS: The telomerase-targeted adenovirus vector has significant potential as an oncolytic virus as well as a tumor-specific therapeutic gene delivery vehicle.

Adenoviridae↗

PubMed2004

[A new orthotopic retinoblastoma model expressing green fluorescent protein].

OBJECTIVE: In order to observe the growth and metastasis of the tumor directly, a new orthotopic retinoblastoma model was established with human RB cells expressing green fluorescent protein (GFP). METHODS: pEGFP-N(1), the eukaryotic expressive plasmid of GFP, was transferred into human RB cell line HXO-RB(44) by liposome Dosper. Then, the cell clones expressing GFP steadily were selected by means of neomycin, fluorescence microscope, and flow cytometer. Two microliters of RB cells (density at 4.5 x 10(8) - 5.5 x 10(8) cells per ml) were injected into the subretinal space of 30 nude mice (60 eyes) under binocular operating microscope. The growth of transplanted RB was observed in vivo using fluorescence stereomicroscope. The nude mice were killed at different times post-operatively to investigate the metastasis process of the tumor to the optic nerve, brain, and other organs including lung, liver and kidney. RESULTS: The spread process of the tumor in the subretinal space was successfully observed under stereomicroscope. Transplanted RB developed into extra-ocular stage phase at 34 - 37 days after the operation. And metastasis to the cranium along the optic nerve was observed, with green RB cells distributing along the optic nerve sheath and long posterior ciliary artery. The histopathological characteristics of the transplanted tumor were similar to the human RB. Immunohistochemical staining showed positive expression of GFP in the tumor cells. CONCLUSION: The established orthotopic RB model expressing GFP via injection of human RB cells into the subretinal space of nude mice provides a new approach to exploring the growth and metastasis processes of RB in natural situations.

Animals↗

PubMed2004

[Subretinal transplantation of genetically modified human retinal pigment epithelium cells delay photoreceptor degeneration and functional deterioration in rats].

OBJECTIVE: To investigate whether subretinal transplantation of genetically modified human retinal pigment epithelium cells can rescue photoreceptor degeneration in RCS rats. METHODS: A spontaneously derived adult human retinal pigment epithelium (RPE) cell line (CRL-2302) was infected by gfp retrovirus, then transfected by liposome mediated CNTF expression plasmid transfer. Around 1 x 10(5) genetic modified cells were injected to subretinal space of the right eye at 4 - 5 weeks old, the left eye was left without injection or injected with PBS as controls. RESULTS: The GFP expression cells under the retina were observed from 1 to 6 weeks after transplantation. Histologic and ultrastructural assessment demonstrated substantial sparing of photoreceptors and correction of RPE phagocytosis defect. Electrophysiological assessment revealed an increased sensitivity of treated eyes to white light. CONCLUSION: The results demonstrate that potential of genetically modified RPE cells for ultimate application in therapeutic transplantation strategies for human retinal degenerative diseases.

Animals↗

PubMed2004

[The structual and temporal characteristics of four intermediate filament proteins during retinal development of rat].

OBJECTIVE: To investigate the markers of retinal progenitor cells and their spatio-temporal characteristics during retinal development of rat. METHODS: The time sequence, location and intensity of the expression of four intermediate filament proteins in retina were studied in rats (from postnatal day 0 to 12 months) by means of immunohistochemistry staining. RESULTS: Retinal differentiation of rat was not accomplished until 2 weeks after birth. Nestin positive cells were seen in neurocytes, glial cells and capillary endothelial cells of rat retina 2 weeks after birth. The number of Nestin positive cells and intensity of Nestin staining in rat retina decreased obviously after 2 weeks of birth then turned to negative at 4 weeks after birth. However, the expression of Nestin was persisted in cells from a few ciliary processes during the development and the intensively positive staining cells were observed in ciliary process, mostly in pigment epithelium cells in adult. In addition, Nestin positive cells were also found in the optic nerve of adult rat. The expression pattern of Vimentin is similar to that of Nestin within 2 weeks after birth. But the expression of Vimentin was persisted with high level lifetime in all glial cells and nonpigment epithelium cells of ciliary. Besides the horizontal cells, positive staining of Vimentin was also found in Muller cells and amacrine cells at 4 weeks after birth. The positive expression of GFAP and neurofilament were only found in mature glial cells and in the axons of ganglion cells, respectively. CONCLUSION: Nestin could be considered as the marker of retinal progenitor cells. Retinal progenitor cells of adult rat are also present in optic nerve and in a few ciliary processes.

Animals↗