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Biomedical subjects

X Dong

Publications and source records attributed to X Dong.

At least 145 records · Page 8Linked to original sources
PubMed1998

[The studies on MTS1/p16 gene deletion during transformation of human bronchial epithelial cells].

OBJECTIVE: To detect the deletion of MTS1/p16 and the expression of P16 protein during the transformation of human bronchial epithelial cell line M. METHODS: Dual-color fluo-rescence in situ hybridization (FISH), immunohistochemical staining and western blot analysis were carried out. RESULTS: No deletion of MTS1/p16 gene was found in MP18 cells of the cell line M. But partial deletions occurred in the MP36 and MP120 cells of the cell line M. Immunohistochemical analysis and western blot test showed lower expression of P16 protein in the MP120 cells than in MP20 cells. CONCLUSIONS: MTS1/p16 gene deletion contributes to the malignant transformation of the human bronchial epithelial cell line M. Also FISH is a useful technique in detecting gene deletion.

Bronchi↗
PubMed1998

[A preliminary observation on nuclear changes of human corneal endothelial cells in different kinds of corneal diseases].

OBJECTIVE: To investigate the influence of different kinds of corneal diseases on corneal endothelial cells. METHODS: The endothelial cells of 91 corneal buttons obtained at the time of penetrating keratoplasty (PKP) were stained by 1% alizarin red and 0.25% trypan blue and observed under biomicroscope. RESULTS: Binuclear and polynuclear endothelial cells were found in every buttons. CONCLUSION: Under special conditions, the human corneal endothelial cells possibly have stronger ability of mitosis and compensation.

Adolescent↗
PubMed1998

[Congenital cataract extraction with intraocular lens implantation in children].

OBJECTIVE: To evaluate the results of cataract extraction with intraocular lens (IOL) implantation in children. METHODS: Cataract extracapsular extraction with anterior vitrectomy and IOL implantation was performed on 104 eyes of 64 children with congenital cataract aged 1.5 - 14 years old. The visual acuity and possible complications were followed up for a mean period of 22 months. RESULTS: After operation 86.4% patients were relieved from blindness, 62.7% obtained corrected vision >or= 0.3, binocular vision and stereopsis were restored in 41.8% and 30.6% respectively. In 3 eyes secondary cataract developed and in 5 eyes slight iris capture occurred. CONCLUSIONS: Cataract extraction with anterior vitrectomy and IOL implantation is effective in pediatric cataract treatment. Most patients get remarkable improvement in visual acuity and visual function with minimal complications after surgery. The influence factors on the postoperative visual function need further study.

Adolescent↗
PubMed1998

[Treatment of intraocular fibrinous membrane by anterior chamber injection of tissue plasminogen activator after IOL implantation].

OBJECTIVE: To investigate the method of treatment of intraocular fibrinous membrane by tissue plasminogen activator (t-PA) after intraocular lens (IOL) implantation and evaluate its clinical results. METHODS: 58 eyes of 43 patients after cataract surgery were divided into three groups, and received t-PA anterior chamber (AC) injection or combined with YAG laser therapy at different times after the operation. Group 1 included 26 eyes which received 4 microg t-PA AC injection at the end of operation. In group 2, 22 eyes whose fibrinous membrane was formed 5 - 7 days after the operation were injected with 4 microg t-PA at that time. In group 3, 10 eyes with thicker membrane were given YAG laser treatment at postoperative 5 - 9 days and then 4 microg t-PA was injected into the AC. RESULTS: In group 1, hyphema occurred in 4 eyes, in 8 eyes at the pupillary region the fibrinous membrane was formed which was completely lysed after t-PA AC injection at postoperative 3 - 5 days. In group 2, the membrane was lysed within 24 hours in 20 of 22 eyes and no hyphema was found. In group 3, the membrane was lysed within 4 - 24 hours after t-PA injection in all cases, and no hyphema occurred. CONCLUSION: It is very effective to treat fibrinous membrane formation after IOL implantation by t-PA AC injection at postoperative 1 week when the AC inflammation is well controlled. The combined use of YAG laser with t-PA AC injection is much more effective for the treatment of such a membrane.

Adolescent↗
PubMed1998

[The choice of intraocular lens before cataract extraction for cases with high myopia].

OBJECTIVE: To study the choice of diopter and size of optical portion of intraocular lens (IOL) before cataract extraction for cases with high myopia. METHODS: Extracapsular cataract extraction (ECCE) or phacoemulsification with IOL implantation was performed on 60 cases (94 eyes) with high myopia (axial length > 26mm). The posterior chamber IOL selected and inserted was the one with the diopter and size of the optical portion suitable for the recipient to have a postoperative low myopia and easy to be examined with an ophthalmoscope. RESULTS: The postoperative eyes were of low myopia, -2.07 +/- 1.95 D. The larger size of optical portion was more suitable for ocular fundus examination. Great care was taken for phacoemulsification for cataractous nucleus below III grade. CONCLUSIONS: For patients with axial myopia, the IOL implanted should create low myopia postoperatively. Larger optic size is better for fundus examination. Phacoemulsification can produce less astigmatism and damage, but the indication must be controlled strictly.

Adolescent↗
PubMed1998

[YY1 and its repressive effect on human papillomavirus 16 early promoter P97 existed widely among human epithelial cell lines].

Cellular transcription factor YY1 represses the activity of early promoter P97 of HPV 16. Removal of the specific binding sites for YY1 in HPV 16 LCR can increase the P97 activity. To analyse the expression of YY1 and the existence of the activation effect on P97 due to removing YY1 binding sites in the LCR region, we extracted nuclear proteins from four cervical cancer cell lines and two human keratinocytes. EMSA assays were carried out in vitro. At the same time, we transiently transfected the luciferase reporter plasmids, which contain HPV 16 reference and mutated LCR sequences, respectively, into the different cells and determined the luciferase expressions. The results showed that all the analysed cell lines contained biologically functional YY1 proteins. No remarkable difference in the concentration of native YY1 proteins could be detected among the tested cells. Removal of YY1 binding sites in HPV 16 LCR could elevate P97 activity in several analysed cell lines, including normal human primary kerationcytes from foreskin. It suggests that YY1 regulatory system exists widely in human epithelial cell lines. We also found that the transcription activator NF1 was more highly expressed in C33a cell than in HT3 cell, indicating an unevenly distribution of functional proteins in various cell lines.

Cells, Cultured↗
PubMed1998

[Implementing a relatively rigorous algorithm of dynamic EIT problem on the modified FEM model].

We deduced a relatively rigorous algorithm of dynamic EIT problem-general inverse algorithm, and implemented it on the computer FEM model. Images which can show the changing of the resistivity(i.e. dynamic resistivity images) were gained. Also we modified the ordinary FEM model according to the characteristic of the EIT problem and implemented the general inverse algorithm on the modified model. The ill-posed condition of the forward matrix based on the modified model was fairly improved. It can be seen from the results that the general inverse algorithm with modified FEM model is an algorithm better than the back-projection algorithm in terms of object locating, image definition, and the ability of dealing with complex object and noise.

Algorithms↗
PubMed1997

roughex down-regulates G2 cyclins in G1.

Cell cycle arrest in G1 at the onset of patterning in the Drosophila eye is mediated by roughex. In roughex mutants, cells accumulate Cyclin A protein in early G1 and progress into S phase precociously. When Roughex is overexpressed in S/G2 cells, Cyclin A is mislocalized to the nucleus and degraded, preventing mitosis. Whereas Roughex inhibits Cyclin A accumulation, Cyclin E down-regulates Roughex protein in vivo. Roughex binds to Cyclin E and is a substrate for a Cyclin E-Cdk complex in vitro. These data argue that Roughex inhibits Cyclin A accumulation in early G1 by targeting Cyclin A for destruction. In late G1, Roughex is destabilized in a Cyclin E-dependent process, releasing Cyclin A for its role in S/G2.

Animals↗
PubMed1997

The Arabidopsis NPR1 gene that controls systemic acquired resistance encodes a novel protein containing ankyrin repeats.

The Arabidopsis NPR1 gene controls the onset of systemic acquired resistance (SAR), a plant immunity, to a broad spectrum of pathogens that is normally established after a primary exposure to avirulent pathogens. Mutants with defects in NPR1 fail to respond to various SAR-inducing treatments, displaying little expression of pathogenesis-related (PR) genes and exhibiting increased susceptibility to infections. NPR1 was cloned using a map-based approach and was found to encode a novel protein containing ankyrin repeats. The lesion in one npr1 mutant allele disrupted the ankyrin consensus sequence, suggesting that these repeats are important for NPR1 function. Furthermore, transformation of the cloned wild-type NPR1 gene into npr1 mutants not only complemented the mutations, restoring the responsiveness to SAR induction with respect to PR-gene expression and resistance to infections, but also rendered the transgenic plants more resistant to infection by P. syringae in the absence of SAR induction.

Amino Acid Sequence↗
PubMed1997

Control of G1 in the developing Drosophila eye: rca1 regulates Cyclin A.

In the developing eye of Drosophila melanogaster, cells become synchronized in the G1 phase of the cell cycle just prior to the onset of cellular differentiation and morphogenesis. In roughex (rux) mutants, cells enter S phase precociously because of ectopic activation of a Cyclin A/Cdk complex in early G1. This leads to defects in cell fate and pattern formation, and results in abnormalities in the morphology of the adult eye. A screen for dominant suppressors of the rux eye phenotype led to the identification of mutations in cyclin A, string (cdc25), and new cell cycle genes. One of these genes, regulator of cyclin A (rca1), encodes a novel protein required for both mitotic and meiotic cell cycle progression. rca1 mutants arrest in G2 of embryonic cell cycle 16 with a phenotype very similar to cyclin A loss of function mutants. Expression of rca1 transgenes in G1 or in postmitotic neurons promotes Cyclin A protein accumulation and drives cells into S phase in a Cyclin A-dependent fashion.

Amino Acid Sequence↗
PubMed1997

Human autoantibodies stabilize the quaternary structure of Ku antigen.

OBJECTIVE: To examine humoral immune responses to the native Ku antigen and to evaluate the role of autoantibodies in stabilizing intermolecular contacts between the p70 and p80 Ku subunits. METHODS: Recombinant free human p70 and p80 Ku subunits and p70/p80 heterodimers were expressed in Sf9 (insect) cells using baculovirus vectors. Affinity-purified recombinant human p70, p80, and p70/p80 dimer were studied by enzyme-linked immunosorbent assay (ELISA) and immunoprecipitation to evaluate autoantibody specificities in sera from 58 patients with systemic autoimmune disease. RESULTS: Anti-Ku antibodies were detected by ELISA or immunoprecipitation using K562 cell Ku antigen. All of the sera were reactive with the native recombinant p70, p80, or p70/p80 antigens: 47% were anti-p70+,anti-p80+ and 32% were anti-p70-,anti-p80+, but only 3% were anti-p70+,anti-p80-. Unexpectedly, 18% of the sera recognized the p70/p80 dimer but did not recognize native p70 or p80 alone. A subset of sera containing autoantibodies that prevent the dissociation of p70 from p80 by high salt and detergent treatment was identified; monoclonal antibody (MAb) 162, a murine anti-Ku MAb, displays the same property. Autoantibodies that stabilize the p70-p80 interaction were found most frequently in sera containing both anti-p70 and anti-p80 antibodies. CONCLUSION: Autoantibodies to the native p80 subunit of Ku are more common than are anti-p70 antibodies. When anti-p70 antibodies were detected, they generally were found together with anti-p80. A novel type of autoantibody capable of stabilizing the p70/p80 heterodimer was identified in human sera for the first time. These "stabilizing" autoantibodies are found in sera containing both anti-p70 and anti-p80 antibodies, and also are produced by mice immunized with human Ku antigen. Autoimmunity to Ku may be initiated with an immune response to p80, followed by spreading to p70. We hypothesize that stabilizing antibodies could facilitate the spreading of autoimmunity from one subunit of Ku to another by altering the processing of p70 or p80 by antigen-presenting cells.

Animals↗
PubMed1997

Generation of H2O2 by human neutrophils and changes of cytosolic Ca2+ and pH of rat thymocytes in response to galactoside-binding proteins (lectins or immunoglobulins).

In contrast to plant agglutinins, biological activities of animal/human lectins are not well defined yet. Testing a panel of seven mammalian carbohydrate-binding proteins we have found that the dimeric lectin from chicken liver (CL-16) was a stimulator of H2O2 release from human neutrophils as well as effector for induction of cytosolic Ca2+ and pH increase in rat thymocytes. Activity of this lectin was comparable to potent galactoside-specific plant lectins such as Viscum album L. agglutinin. The activities of the tested plant lectins depended significantly on their nominal carbohydrate specificity as well as on the source. The results indicate that endogenous lectins may be involved in the regulation of neutrophil and lymphocyte functions by elicitation of selective biosignaling reactions.

Amiloride↗
PubMed1997

Expression of soluble, active human macrophage colony stimulating factor in Escherichia coli.

Human macrophage colony stimulating factor (M-CSF) has been successfully overexpressed in Escherichia coli AD494 (DE3) with an expression level of approximate 26% of the total cellular proteins. The truncated human M-CSF gene encoding the amino-terminal 149 amino acids was subcloned into the prokaryotic expression vector pET11d under the control of the inducible T7 promoter. Nearly 40% of the recombinant protein was in the soluble fraction which showed obvious stimulating effects on mouse macrophage colony formation and had an M-CSF specific activity of approximately 1 x 10(6) units/mg soluble protein.

Animals↗
PubMed1997

Glycine68 to histidine73 has an important role in the function of human tumor necrosis factor alpha.

Mutant human tumor necrosis factor alpha(hTNF alpha) genes have been constructed by in vitro mutagenesis and expressed in Escherichia coli. A deletion involving Gly68 to His73 in hTNF alpha remarkably decreased the solubility and biological activity of hTNF alpha. From the above and results of a molecular dynamics simulation it is proposed that the region of Gly68 to His73 in hTNF alpha has an important role in the maintenance of the 3-D structure and modulation of the biological activity of hTNF alpha.

Amino Acid Sequence↗
PubMed1997

The cpr5 mutant of Arabidopsis expresses both NPR1-dependent and NPR1-independent resistance.

The cpr5 mutant was identified from a screen for constitutive expression of systemic acquired resistance (SAR). This single recessive mutation also leads to spontaneous expression of chlorotic lesions and reduced trichome development. The cpr5 plants were found to be constitutively resistant to two virulent pathogens, Pseudomonas syringae pv maculicola ES4326 and Peronospora parasitica Noco2; to have endogenous expression of the pathogenesis-related gene 1 (PR-1); and to have an elevated level of salicylic acid (SA). Lines homozygous for cpr5 and either the SA-degrading bacterial gene nahG or the SA-insensitive mutation npr1 do not express PR-1 or exhibit resistance to P. s. maculicola ES4326. Therefore, we conclude that cpr5 acts upstream of SA in inducing SAR. However, the cpr5 npr1 plants retained heightened resistance to P. parasitica Noco2 and elevated expression of the defensin gene PDF1.2, implying that NPR1-independent resistance signaling also occurs. We conclude that the cpr5 mutation leads to constitutive expression of both an NPR1-dependent and an NPR1-independent SAR pathway. Identification of this mutation indicates that these pathways are connected in early signal transduction steps and that they have overlapping functions in providing resistance.

Arabidopsis↗
PubMed1997

[Cataract extraction combined intraocular lens implantation through corneal incision].

OBJECTIVE: We reported the clinical results of the extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation through a corneal incision. METHODS: The ECCE with IOL implantation was performed through a stepped corneal incision within limbus 1.0-1.5 mm. The changes of intraocular pressure (IOP), endothelia and astigmatism were observed. RESULTS: The IOP has no significant changes, and the rate of endothelial cells loss (12.55%) also has no significant differences compared with routine cataract extraction. The corneal astigmatism became 0.96 DC with the rule after operation. CONCLUSION: For complicated cataract after trabeculectomy, uveitis with pupillary block, and serious diabetic cataract, the intraocular surgery through a corneal incision is effective and safe.

Adolescent↗
PubMed1997

[Voice rehabilitation with double-valve voice prosthesis after laryngectomy].

Between March 1993 and November 1996, 97 laryngectomized patients underwent voice rehabilitation with prostheses designed by ourselves. Of these patients, 84 were males and 13 females. The age ranged from 35 to 78 years. 20 cases had the prosthesis inserted during the laryngectomy operation (first stage), while other 77 cases were inserted after the laryngectomies (second stage). The results showed that all of the patients had clear voice with their own local dialect. 34 of them could even sing songs. 68 cases had been followed-up for 2 years. All could speak during the effective time of the prosthesis and no misswallow occurred.

Adult↗