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Biomedical subjects

Bin Yu

Publications and source records attributed to Bin Yu.

At least 55 records · Page 3Linked to original sources
PubMed2004

Posterior selective thoracic fusion in adolescent idiopathic scoliosis.

OBJECTIVE: To define the criteria of posterior selective thoracic fusion in patients with adolescent idiopathic scoliosis. METHODS: By reviewing the medical records and roentgenograms of 17 patients with adolescent idiopathic scoliosis who underwent posterior selective thoracic fusion, the curve type, Cobb angle, apical vertebral rotation and translation, trunk shift, and thoracolumbar kyphosis were measured and analyzed. RESULTS: There were 17 King type II patients (PUMC type: IIb, 13, IIc3 4). The coronal Cobb angle of thoracic curve before and after operation were 56.9 degrees and 21.6 degrees respectively, the mean correction rate was 60.1%. The coronal Cobb angle of lumbar curve before and after operation were 34.8 degrees and 12.1 degrees respectively, and the mean spontaneous correction rate was 64.8%. At final follow-up, the coronal Cobb angle of thoracic and lumbar curve were 23.5 degrees and 15.2 degrees respectively, there were no significant changes in the coronal Cobb angle, apical vertebral translation and rotation compared with that after operation. One patient had 12 degrees of thoracolumbar kyphosis after operation, no progression was noted at final follow-up. There was no trunk decompensation or deterioration of the lumbar curve. In this group, 3.9 levels were saved compared with fusing both the thoracic and lumbar curves. CONCLUSION: Posterior selective thoracic fusion can be safely and effectively performed in King type II patients with a moderate and flexible lumbar curve, which can save more mobile segments and at the same time can maintain a good coronal and sagittal balance.

Adolescent↗
PubMed2004

[Study on the synthesis, characterization of structure and fluorescence properties of the solid complex of europium ion with 1,10-phenanthroline and 2-thiopheneglyoxylic acid].

The complex of europium with 1,10-phenanthroline and 2-thiopheneglyoxylic acid (HL) was synthesized. Its chemical formula was determined to be [EuL2 x phen x (H2O)3]NO3 by elemental analysis, electrical conductivity, IR and 1H NMR. It was found that the europium ion coordinated to the O atoms of 2-thiopheneglyoxylic acid and H2O, and to the N atoms of 1,10-phenanthroline. Its fluorescence property was determined by the excitation and emission spectra at room temperature, the emission peaks at 592 and 618 nm were assigned to the 5D0-7F1 and 5D0-7F2, respectively. It was also observed that the title complex emits strong red fluorescence under ultraviolet light at room temperature. In the IR spectrum, the characteristic absorption nu(C=O) (1719 cm(-1)), nu(C-O) (1232 cm(-1)), delta(O-H) (909 cm(-1)) of 2-thiopheneglyoxylic acid disappeared in the complex, the nu(as) and nu(s) of -COO- appeared at 1642 and 1408 cm(-1) in the complex respectively. In 1H NMR, the signals of 2-thiopheneglyoxylic acid were shifted upfield, and those of 1,10-phenanthroline downfield. It is proved by the TG curve that the complex is stable from ambient temperature to 250 degrees C.

Europium↗
PubMed2003

Full-length dominant-negative survivin for cancer immunotherapy.

PURPOSE: The goal of this study is to investigate the possible utility of dendritic cells (DCs) transduced with the human full-length dominant-negative survivin for cancer immunotherapy. EXPERIMENTAL DESIGN: Mononuclear cells were collected from HLA-A2-positive healthy volunteers and patients with prostate cancer. DCs were transduced with an adenoviral vector containing a full-length, dominant-negative survivin gene. After three rounds of stimulation, the T-cell response against three different survivin-derived HLA-A2-matching peptides was tested in IFN-gamma enzyme-linked immunospot and CTL assays. RESULTS: Seven of eight healthy volunteers and cancer patients showed a significant response to at least two different survivin-derived epitopes in the enzyme-linked immunospot assay. One patient responded to only one peptide. All four healthy volunteers and two of three patients tested demonstrated a specific CTL response against T2 target cells loaded with one survivin-derived epitope. Two donors and two patients had a significant CTL response against two different epitopes. Significant cytotoxic activity was seen against HLA-A2-positive MCF-7 tumor cells that express survivin. That response was specific for survivin and was MHC class I restricted. Because survivin is expressed in CD34(+) hematopoietic progenitor cells (HPCs), we tested whether the antisurvivin CTLs can recognize normal HPCs. The incubation of survivin-specific CTLs with CD34(+) cells did not significantly decrease the colony-forming ability of HPCs. CONCLUSIONS: DCs transduced with dominant-negative survivin induce potent survivin-specific CTL responses able to recognize and kill tumor cells. This response does not significantly affect HPCs. Thus, this study may provide rationale for immunotherapeutic clinical trials using a DC vaccine transduced with the dominant-negative survivin.

Adenoviridae↗
PubMed2003

Role of an N-terminal site of Ubc9 in SUMO-1, -2, and -3 binding and conjugation.

Covalent posttranslational modification of target proteins with ubiquitin and ubiquitin-like proteins regulates many important cellular processes. However, the molecular mechanisms by which these proteins are activated and conjugated to substrates has yet to be fully understood. NMR studies have shown that the ubiquitin-like proteins SUMO-1, -2, and -3 interact with the same N-terminal region of the E2 conjugating enzyme Ubc9 with similar affinities. This is correlated to their almost identical utilization by Ubc9 in the SUMO conjugation pathway. To investigate the functional significance of this interaction, site-directed mutagenesis was used to alter residues in the SUMO binding surface of Ubc9, and the effect of the amino acid substitutions on binding and conjugation to SUMO-1 and target protein RanGAP1 was investigated by isothermal titration calorimetry and biochemical analysis. R13A/K14A and R17A/K18A mutations in Ubc9 disrupted the interaction with SUMO-1 but did not completely abolish the interaction with E1. While these Ubc9 mutants displayed a significantly reduced efficiency in the transfer of SUMO-1 from E1 to E2, their ability to recognize substrate and transfer SUMO-1 from E2 to the target protein was unaffected. These results suggest that the noncovalent binding site of SUMO-1 on Ubc9, although distant from the active site, is important for the transfer of SUMO-1 from the E1 to the E2. The conservation of E2 enzymes across the ubiquitin and ubiquitin-like protein pathways indicates that analogous N-terminal sites of E2 enzymes are likely to have similar roles in general.

Amino Acid Sequence↗
PubMed2003

Local estrogen formation by nontumoral, cirrhotic, and malignant human liver tissues and cells.

We have investigated the activity and expression of aromatase enzyme in nontumoral, cirrhotic, and malignant human liver tissues and cells using both chromatographic and reverse transcription (RT)-PCR analyses. After 24- and 72-h incubation of tissue minces or hepatic cell lines with either testosterone or androstenedione as androgen precursor, human hepatocellular carcinoma (HCC) tissues and HepG2 hepatoma cells showed elevated aromatase activity, with estrogen formation rates being 20 and >95%, respectively, as opposed to nontumoral hepatic tissues and nonmalignant Chang liver (CL) cells, where no aromatase activity could be detected. Cirrhotic samples exhibited intermediate enzyme activity. Notably, exposure of HepG2 cells to the aromatase inhibitor Letrozole resulted in a striking decrease of estrogen formation, which became virtually absent at a Letrozole dose of 0.4 nM. RT-PCR analysis revealed markedly lower aromatase mRNA in both CL cells and nontumoral liver tissues, as compared with HepG2 cells and HCC samples. Cirrhotic specimens displayed variable transcript levels, in turn comparable with those observed in nontumoral or HCC tissues. Exon-specific RT-PCR showed prominent expression of exon I.3A-containing message and exon I.4-containing message in CL and HepG2 cells, as in nontumoral and HCC tissues, respectively. The present evidence implies that locally elevated estrogen formation in malignant human liver tissues and cells may have a role in the development and/or maintenance of human HCC, eventually leading to develop alternative strategies for treatment of HCC patients using antiaromatase agents.

Androgens↗
PubMed2003

All-trans-retinoic acid eliminates immature myeloid cells from tumor-bearing mice and improves the effect of vaccination.

Tumor-induced immunosuppression is one of the crucial mechanisms of tumor evasion of immune surveillance. It contributes greatly to the failure of cancer vaccines. Immature myeloid cells (ImCs) play an important role in tumor-induced immunosuppression. These cells accumulate in large numbers in tumor-bearing hosts and directly inhibit T-cell functions via various mechanisms. In this study, we tried to eliminate ImCs in an attempt to improve antitumor response. In vivo administration of all-trans-retinoic acid (ATRA) dramatically reduced the presence of ImCs in all tested tumor models. This effect was not because of a direct antitumor effect of ATRA or decreased production of growth factors by tumor cells. Experiments with adoptive transfer demonstrated that ATRA differentiated ImC in vivo into mature dendritic cells, macrophages, and granulocytes. Decreased presence of ImC in tumor-bearing mice noticeably improved CD4- and CD8-mediated tumor-specific immune response. Combination of ATRA with two different types of cancer vaccines in two different tumor models significantly prolonged the antitumor effect of the treatment. These data suggest that elimination of ImC with ATRA may open an opportunity to improve the effect of cancer vaccines.

Adenocarcinoma↗
PubMed2003

Simultaneous gene clustering and subset selection for sample classification via MDL.

MOTIVATION: The microarray technology allows for the simultaneous monitoring of thousands of genes for each sample. The high-dimensional gene expression data can be used to study similarities of gene expression profiles across different samples to form a gene clustering. The clusters may be indicative of genetic pathways. Parallel to gene clustering is the important application of sample classification based on all or selected gene expressions. The gene clustering and sample classification are often undertaken separately, or in a directional manner (one as an aid for the other). However, such separation of these two tasks may occlude informative structure in the data. Here we present an algorithm for the simultaneous clustering of genes and subset selection of gene clusters for sample classification. We develop a new model selection criterion based on Rissanen's MDL (minimum description length) principle. For the first time, an MDL code length is given for both explanatory variables (genes) and response variables (sample class labels). The final output of the proposed algorithm is a sparse and interpretable classification rule based on cluster centroids or the closest genes to the centroids. RESULTS: Our algorithm for simultaneous gene clustering and subset selection for classification is applied to three publicly available data sets. For all three data sets, we obtain sparse and interpretable classification models based on centroids of clusters. At the same time, these models give competitive test error rates as the best reported methods. Compared with classification models based on single gene selections, our rules are stable in the sense that the number of clusters has a small variability and the centroids of the clusters are well correlated (or consistent) across different cross validation samples. We also discuss models where the centroids of clusters are replaced with the genes closest to the centroids. These models show comparable test error rates to models based on single gene selection, but are more sparse as well as more stable. Moreover, we comment on how the inclusion of a classification criterion affects the gene clustering, bringing out class informative structure in the data. AVAILABILITY: The methods presented in this paper have been implemented in the R language. The source code is available from the first author.

Algorithms↗
PubMed2003

Black diaphragm intraocular lens implantation in aphakic eyes with traumatic aniridia and previous pars plana vitrectomy.

PURPOSE: To evaluate the efficacy of secondary black diaphragm intraocular lens (IOL) implantation in aphakic eyes with traumatic aniridia and previous pars plana vitrectomy (PPV). SETTING: Shandong Eye Institute and Hospital, Qingdao, China. METHODS: This retrospective study comprised 15 aphakic eyes with aniridia and no vitreous that had implantation of a secondary black diaphragm IOL 6 to 72 months after PPV. The PPV was performed as a result of trauma to the posterior segment. Before implantation of the IOL, all patients had reduced visual acuity from aphakia and intolerable glare from aniridia. Eyes were aphakic as a result of previous extracapsular cataract extraction (1 eye), lens extrusion during trauma (3 eyes), or simultaneous cataract lensectomy during PPV (11 eyes). Significant iris defects were present, with 9 eyes being aniridic after the injury. The mean follow-up was 17 months (range 3 to 34 months). The postoperative visual acuity, intra- ocular pressure (IOP), endothelial cell density, IOL centration, and intraocular inflammation were monitored. RESULTS: All 15 eyes had improved visual acuity and marked glare reduction after IOL implantation. No major IOL decentration was seen. Five patients had increased IOP 3 to 5 days after IOL implantation; 3 were known to have secondary glaucoma from trauma before surgery and their IOP was controlled preoperatively (< 21 mm Hg) with timolol 0.5% eyedrops. The other 2 patients had normal- appearing angles, and 1 was diagnosed with hemolytic glaucoma after IOL insertion. Postoperative elevated IOP was controlled by timolol eyedrops (4 eyes) or selective laser trabeculoplasty (1 eye). Hyphema was seen in 1 patient on the first day after IOL implantation, but no further bleeding was noted. Vitreous hemorrhage was seen the first day after IOL insertion in 2 patients. One resolved without sequelae; the other required vitreous washout. Retinal detachment and cystoid macular edema did not occur in any patient. CONCLUSIONS: Black diaphragm IOL implantation can be considered in eyes with coexisting aphakia and aniridia and without vitreous. Intraoperative IOP regulation is crucial in vitrectomized eyes to prevent complications such as expulsive hemorrhage. In general, visual function was better after IOL insertion as a result of better visual acuity and glare reduction. Although this IOL appears to be safe, long-term results must be assessed in studies with a longer follow-up and a larger study group.

Adolescent↗
PubMed2003

Production of ribosome components in effector CD4+ T cells is accelerated by TCR stimulation and coordinated by ERK-MAPK.

Effector CD4+ T cells rapidly activate high-level cytokine expression following TCR stimulation. Consistent with accelerated protein production in these cells, global mRNA profiles revealed that, after cytokines, the most impressive cluster of activated genes encode rRNA-maturation factors. Activation of these genes was ERK-MAPK dependent, accompanied by increased rRNA transcription and faster maturation kinetics, and much greater in effector CD4+ T cells than in naive cells. Ribosomal protein subunit (RPS) synthesis was also ERK-MAPK dependent and increased to match rRNA production, but without evident increase in RPS mRNA. Instead, stimulation promoted polysome loading of RPS mRNA via cis-acting, 5'-terminal oligopyrimidines. These results demonstrate how, in response to extracellular signals, effector CD4+ T cells coordinately increase multiple ribosomal components to accommodate burgeoning cytokine production.

Animals↗
PubMed2003

Anionic lipids are required for chloroplast structure and function in Arabidopsis.

Photosynthetic membranes of plants primarily contain non-phosphorous glycolipids. The exception is phosphatidylglycerol (PG), which is an acidic/anionic phospholipid. A second major anionic lipid in chloroplasts is the sulfolipid sulfoquinovosyldiacylglycerol (SQDG). It is hypothesized that under severe phosphate limitation, SQDG substitutes for PG, ensuring a constant proportion of anionic lipids even under adverse conditions. A newly constructed SQDG and PG-deficient double mutant supports this hypothesis. This mutant, sqd2 pgp1-1, carries a T-DNA insertion in the structural gene for SQDG synthase (SQD2) and a point mutation in the structural gene for phosphatidylglycerolphosphate synthase (PGP1). In the sqd2 pgp1-1 double mutant, the fraction of total anionic lipids is reduced by approximately one-third, resulting in pale yellow cotyledons and leaves with reduced chlorophyll content. Photoautotrophic growth of the double mutant is severely compromised, and its photosynthetic capacity is impaired. In particular, photosynthetic electron transfer at the level of photosystem II (PSII) is affected. Besides these physiological changes, the mutant shows altered leaf structure, a reduced number of mesophyll cells, and ultrastructural changes of the chloroplasts. All observations on the sqd2 pgp1-1 mutant lead to the conclusion that the total content of anionic thylakoid lipids is limiting for chloroplast structure and function, and is critical for overall photoautotrophic growth and plant development.

Anions↗
PubMed2003

[Treatment of 48 cases of frozen shoulder with manual therapy under brachial plexus anesthesia through a retained tube].

Manual therapy was adopted for treatment of 48 patients with frozen shoulder, under brachial plexus block through a tube that was not withdrawn until 1 to 2 weeks after the initiation of the treatment course. Satisfactory results were achieved in most of the patients after the treatment, indicating the safety and feasibility of brachial plexus block for pain relief through long-term retention of the tube.

Adult↗
PubMed2003

Effective combination of chemotherapy and dendritic cell administration for the treatment of advanced-stage experimental breast cancer.

PURPOSE: The goal of this study was to investigate the utility of a new approach to the treatment of advanced stage breast cancer, a combination of chemotherapy and dendritic cell (DC) administration. EXPERIMENTAL DESIGN: Mice bearing mammary adenocarcinoma expressing a model tumor antigen, influenza virus HA (DA3-HA), and parental tumor (DA3) were treated with different doses of paclitaxel with or without DCs. Paclitaxel was injected three times weekly, DCs were injected either i.v. or into tumor site (t.s.) 36 h after each injection of paclitaxel. Apoptosis was measured using Annexin V binding or terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assays. CD8-mediated response of T cells to HA-derived peptide epitope was measured in an enzyme-linked immunospot (ELISPOT) assay. CD4-mediated response of T cells to HA-derived peptide was measured in proliferation assay. Nonspecific T-cell proliferation was measured in response to ConA and immobilized anti-CD3 and anti-CD28 antibodies. RESULTS: We have selected the dose of paclitaxel that induced a substantial level of apoptosis and moderate inhibition of T-cell function. Combined treatment resulted in the induction of HA-specific CD8-mediated response in all nine of the tested mice, and CD4-mediated responses in four of six treated mice. These effects were observed only if DCs were injected into tumor site, but not when injected i.v. No specific responses were found in mice treated with either chemotherapy or DCs alone. Injection of dexamethasone together with paclitaxel did not affect the induction of immune responses. Significant antitumor effect of combined treatment was observed in DA3-HA tumor-bearing mice as well as in mice bearing parental DA3 tumor. CONCLUSION: The combination of DC administration with repeated cycles of chemotherapy and dexamethasone (conditions similar to real clinical practice) resulted in the induction of antitumor response despite the immunosuppression induced by such treatment.

Animals↗
PubMed2003

[Comparison of incidence of BPH and related factors between urban and rural inhabitants in district of Wannan].

OBJECTIVES: To investigate the difference of BPH incidence in two groups. METHODS: 309 cadres and 314 farmers over 60 years old in district of Wannan have been investigated. The investigation included prostate volume (V), IPSS, L, Qmax, residual urine (R) and dietary constituents. RESULTS: The intake of animal protein in cadres is more than that in farmers (u = 24.10, P < 0.01), and the incidence rate of BPH is significantly higher (91.1% vs 11.8%, chi 2 = 24.64, P < 0.001). Logistic regression shows that the intake of animal protein has a parallel relationship with BPH. CONCLUSIONS: In the district of Wannan, the incidence of BPH in cadres is significantly higher than that of farmers, and it may be correlated with the amount of animal protein intake.

Aged↗
PubMed2003

[In vitro degradation and subsequent biomechanical changes of poly(lactide-co-glycolide) scaffolds prepared by mild heating under high pressure].

OBJECTIVE: To study the changes in biomechanics and such indices as intrinsic viscosity poly (lactide-co-glycolide) (PLGA) scaffolds produced by mild heating under high pressure after in vitro degradation. METHODS: PLGA scaffolds with the porosity of 90.0% and 92.5% respectively were immerged in 37 degrees Celsius; saline for 8 weeks, and the changes in their mass, intrinsic viscosity and loss of compressive strength were assessed on a weekly basis, and the acidity of the degradation solution was also measured regularly. RESULTS: Significant differences was noted in the mass reduction between the scaffolds, and the intrinsic viscosity began to decrease in both groups in the first week to half of the original value till the sixth week. A 50% reduction in the compressive strength of the scaffolds occurred at the fourth week, and till the eighth week, obvious structural collapse was observed. Along with the changes, the acidity of the degradation solution increased from 6.0 to 6.5, and the solution of 90.0% porosity group had lower pH value during the first 4 weeks than 92.5% porosity group, but such difference was no longer seen afterwards. CONCLUSIONS: PLGA scaffolds made by mild heating under high pressure have stable biomechanical performance with the half-life of approximately 6 weeks, which can be applicable for tissue engineering.

Biomechanical Phenomena↗
PubMed2003

[Effect of antioxidant vitamins on the exercise performance of rats].

OBJECTIVE: To investigate the effect of antioxidant vitamins (vitamin E and vitamin C) on the exercise performance of rats. METHODS: Fifty male SD rats were randomly divided into control group (C), exhausting exercise control group (E), vitamin E group (M1), vitamin C group (M2) and vitamin E plus vitamin C group (M3). The rats in the exercising groups (E, M1, M2, M3) were propelled for repeated exhausting runs on the treadmill for 4 weeks. RESULTS: Exclusive use of oral vitamin E or in combination with vitamin C significantly improved the body mass, total exercise treadmill length and net mass of rat quadriceps femoris after the 4-week exercise. No difference was noted between the rats taking oral vitamin C or E alone. The rats in M1, M2 and M3 groups had lower malondialdehyde (MDA) and free calcium content in the quadriceps femoris than the control rats, and SOD activities in the quadriceps femoris mitochondria of rats in the former 3 groups were significantly higher than those of the control group. CONCLUSIONS: Vitamin E can protect the mitochondria in the skeletal muscles and improve the exercise performance of rats, the effect of which can be enhanced by vitamin C, but vitamin C alone can not sufficiently achieve the effects.

Animals↗
PubMed2003

[Ultrastructural changes of the skeletal muscle cells of rats subjected to exhausting exercises and the protective effect of vitamin E].

OBJECTIVE: To investigate the ultrastructural changes of the mitochondria in the skeletal muscle cells of rats subjected to repeated exhausting exercises on treadmill and the protective effect of oral vitamin E. METHODS: Thirty male SD rats were randomized into control group (n=10), exhausting exercise group (n=10) and exhausting exercise group with oral vitamin E treatment (n=10), with the latter two groups taking repeated exhausting running exercises on the treadmill in a course of 4 weeks. At the end of the course of exercises, the rats were sacrificed and the quadriceps femoris muscles isolated for observation the ultrastructures of the skeletal muscle cells by transmission electron microscope (TEM). RESULTS: After 4-week exhausting exercises, the myofilaments of the skeletal muscle were seen in disordered alignment, and the mitochondria exhibited abnormal morphological changes of swelling and vacuolar degeneration. In vitamin E-treated rats also undertaking the exercise, the ultrastructures of the skeletal muscle cells were almost normal as compared with the normal control group. CONCLUSION: Vitamin E can protect the function of the skeletal muscle mitochondria of rats taking repeated exhausting exercises.

Animals↗
PubMed2003

[Anterior thoracoscopic approach of thoracic spine in adolescent idiopathic scoliosis].

The use of anterior surgical techniques for the treatment of adolescent idiopathic scoliosis (AIS) has increased recently and anterior discectomy, anterior release and fusion, instrumentation of the thoracic scoliosis can be performed through a thoracoscopic approach. The thoracoscopic approach has several advantages: small surgical trauma, early return to work, reduced postoperative pain and improved postoperative respiratory functions. Although the thoracoscopic approach still has some shortcomings currently, it will be widely accepted with further development of this technique and instrumentations in the future.

Adolescent↗