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Biomedical subjects

X Song

Publications and source records attributed to X Song.

At least 73 records · Page 4Linked to original sources
PubMed2000

[Cause and management of dislocated nuclear fragments during phacoemulsification].

OBJECTIVE: To investigate the cause and management of posteriorly dislocated lens nucleus in the vitreous cavity during phacoemulsification. METHODS: The authors performed a retrospective study of 18 patients with dislocation of nuclear fragment into vitreous cavity during phacoemulsification at Tong Ren Hospital from August 1994 to January 1999. RESULTS: 4 cases with dislocated nuclei floated in the anterior vitreous were removed by a lens loop from limbal extensive incision. 2 cases with their dislocated nuclei less than 1/4 of the normal size were under follow-up for 3 - 4 years, and no complications were observed. The final outcome in 1 case with a dislocated nucleus half of its normal size was ocular atrophy as a result of phacoanaphylactic endophthalmitis. 11 cases underwent pars plana vitrectomy. In the operation the nuclei were floated anteriorly by injection of perfluoro-1, 3-dimethylcyclohexane, then they were removed by a lens loop through the limbus and in 2 cases they were fragmented by ultrasound. The main post-operative complication was corneal edema. The final visual acuities generally were improved in varying degrees in 1 month to 4 years of follow-up. CONCLUSIONS: During phacoemulsification, the dislocation of a nucleus is liable to first occur in the peripheral sculpting stage, and secondly in central sculpting stage. A radial tear extending posteriorly from a discontinuous anterior capsulorrhexis is the major risk factor predisposing to posterior dislocation of the nucleus or nuclear fragment. During phacoemulsification, vitrectomy should be performed as soon as possible for a nucleus dislocated into middle or posterior vitreous cavity, and it is a safe and effective method for management of dislocated nucleus.

Adult↗
PubMed2000

[The ultrastructure of human and mouse cataractous lens epithelial cell apoptosis].

OBJECTIVE: To observe the relation between human senile cataract, mouse congenital cataract and lens epithelial cell apoptosis. METHODS: Transmission electron microscope was used to observe the apoptotic morphology of the lens epithelial cells in 4 cases with senile cataract and in 2 mice with congenital cataract. The comparisons were made between the cataractous and normal transparent lens epithelial cells in human being and mice. RESULTS: The apoptotic cells were found in senile cataract and mouse congenital cataract lens epithelial cells, while in all control lens epithelial cells they were few. CONCLUSION: Lens epithelial cells apoptosis is related to senile cataract and mouse congenital cataract formation.

Animals↗
PubMed2000

[Trabeculectomy combined with phacoemulsification for treatment of glaucoma complicated with cataract].

OBJECTIVE: To evaluate the effectiveness of small-incision triple procedure, including phacoemulsification, posterior chamber intraocular lens implantation and trabeculectomy, in patients with coexisting glaucoma and cataract. METHODS: Twenty patients (26 eyes) with coexisting glaucoma and cataract underwent 3.5 mm-incision triple procedure. The mean follow-up was 16.1 months (3 - 41 months). RESULTS: The mean preoperative intraocular pressure (IOP) was (23.01 +/- 2.63) mm Hg (1 mm Hg = 0.133 kPa) which decreased to a mean postoperative IOP of (13.93 +/- 1.85) mm Hg (P < 0. 001). Seventeen (65%) of 26 eyes had a best-corrected visual acuity of >or= 0.6 at the last follow-up (range, 0.05 - 1.0). The mean magnitude of astigmatism was 0.81 D (range, 0 - 3.00 D), 4 eyes had no astigmatism. Although 2 eyes used antiglaucoma medications shortly after the surgery, no eyes used any medications at the last follow-up. The early postoperative complications included corneal edema in 5 eyes (19%) and shallow anterior chamber in 3 eyes (12%). The late complication was mainly the after cataract in 6 eyes (23%). CONCLUSIONS: The small-incision triple procedure appears effective for treating selected patients with coexisting cataract and glaucoma, improving the valid visual acuity rapidly, reducing intraocular pressure with less medications and having less postoperative complications.

Adult↗
PubMed2000

[The effect of fluoride-arsenic exposure on the lipid peroxidation and antioxidation of the offspring of rats].

OBJECTIVE: To provide information on the effects of the offspring of rats exposed to fluoride-arsenic. METHODS: The levels of lipid peroxidation and the abilities of antioxidation were determined in the blood of the rats and their offsprings under two generations-one nest reproductive test. RESULTS: The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the blood decreased with the increase of exposure dose. For example, the activity of SOD, was 14.56, 13.74, 11.89 and 11.21 micromol x min(-1) x mg Hb(-1) in different dose groups of F(2), respectively. In contrast, the concentration of lipid peroxides (LPO) increased. Eight weeks after exposure, the activities of SOD and GSH-Px increased, the activity of SOD was 13.97, 13.55, 13.47 and 12.76 micromol x min(-1) x mg Hb(-1), respectively, and the concentration of LPO returned to normal level. CONCLUSION: Fluoride-arsenic exposure can cause oxidative damage of the rat's offspring.

Animals↗
PubMed2000

[Study on the DNA gyrA gene mutation with resistance to fluoroquinolones in Staphylococcus aureus isolated from patients].

This study was aimed at the mechanism of resistance to fluoroquinolones in Staphylococcus aureus isolated from patients in Chengdu. The relationship between the point mutations in the gyrA genes and the resistance of 63 strains (57 fluoroquinone-resistant strains and 6 wild types) isolated clinically in Chengdu were investigated by a combination of restriction fragment length polymorphism analysis. The results revealed that there are 67.27%-92.5% of the fluoroquinolone-resistant strains against norfloxacin, fleroxacin, tosufloxacin, cipofloxacin, ofloxacin and sparfloxacin had a Hinf I site mutation in the gyrA genes, and most of such strains with such mutation in the gyrA genes showed high-level resistance. These indicate that Hinf site mutation in gyrA genes is the mainly cause of the resistance of fluoroquinolone-resistant strains of Staphylococcus aureus in Chengdu region.

Anti-Infective Agents↗
PubMed2000

[The clinical study of tongue flaps repairing after resecting pharyngeal neoplasm and laryngeal neoplasm].

OBJECTIVE: To study the repair methods of the defect after resecting pharyngeal neoplasm and laryngeal neoplasm. METHODS: Four kinds of tongue flap, such as 1/3 tongue flap, 1/2 tongue base flap, tongue base flap and transverse tongue flap were devised and applied in 15 patients with pharyngeal neoplasm and laryngeal neoplasm. RESULTS: These tongue flaps were alive in all patients. The wound of 13 patients healed in I stage. Two patients dehiscenced because of infection and healed after treatment. All the patients deglutited well. One-year, 3-year, disease-free survive rate were 92.9% (13/14), 72.7% (8/11) respectively. CONCLUSION: Tongue flaps are obtained easily, with enough blood flow, adapted to pharyngeal environment, easily alive and low complication in repairing the pharyngeal defect. We think that these tongue flaps should be applied in clinic.

Adult↗
PubMed2000

[Induction of skin immune tolerance of mouse to rat xenogeneic transplantation].

OBJECTIVE: To explore a moderate and effective project which will be clinically suitable to induce donor-specific tolerance across xenogeneic barriers. METHODS: 4 x 10(7) Lewis rat bone marrow cells were infused to 300 rad total body irradiated (TBI) C57BL/6 (B6) mice, combined with intraperitoneal administration of cyclophosphamide (CTX) and intravenous injection of anti-mouse CD4 monoclonal antibody. Recipient B6 mice were characterized for the tolerance status with donor Lewis rat skin graft, mixed lymphocyte reaction (MLR), and delayed-type hypersensitivity (DTH) assays after 30 days. Adoptive transfer and the effect of IL-2 on MLR were detected to further explore the tolerance mechanism. RESULTS: Survival time of donor rat skin grafts was specifically prolonged in the tolerant B6 mice. The results of MLR and DTH assays showed donor-specific hyporeactivity, while the tolerant B6 mice were still immunocompetent to MHC-disparate third party BALB/c mouse or DA rat stimulator cells. CONCLUSIONS: A reliable xenogeneic transplantation tolerance of mouse to rat was achieved by this project of tolerance induction. The result of in vitro and in vivo adoptive transfer of spleen cells from tolerant B6 mice demonstrated that the suppressor cells were unlikely to exert effect in the tolerance. The inhibition of specific MLR could be reversed by adding IL-2, indicating that clonal anergy instead of clonal deletion is responsible for the tolerant maintenance.

Animals↗
PubMed1999

Generation of anti-hirudin antibodies in heparin-induced thrombocytopenic patients treated with r-hirudin.

BACKGROUND: Hirudin is a small protein with strong thrombin inhibition that may be antigenic. The generation and disappearance of anti-hirudin antibodies were investigated in patients with heparin-induced thrombocytopenia who were treated with recombinant hirudin (r-hirudin) for >/=5 days. METHODS AND RESULTS: The IgA, IgE, IgG, and IgM isotypes of anti-hirudin antibodies were determined by ELISA before and after the start of r-hirudin therapy. A total of 56% of patients (13 of 23) developed >/=1 antibody isotype during therapy. No IgE antibodies were generated. IgA, IgG, and IgM antibodies were detected in 30% (7 of 23), 52% (12 of 23), and 17% (4 of 23) of patients, respectively. Four patients generated only IgG, 2 patients developed either IgM or IgG and IgM, 5 patients IgG and IgA, and 2 patients IgG, IgM, and IgA antibodies. IgM antibodies disappeared within 8 days of the cessation of r-hirudin. IgA and IgG antibodies disappeared within 1 year in all but 1 patient. Binding of purified IgG to r-hirudin in IgG antibody-positive patients (n=7) was demonstrated by competitive ELISA for r-hirudin. Of the 7 IgG antibody samples, 1 each neutralized or enhanced the anticoagulant activity of r-hirudin. CONCLUSIONS: R-hirudin may be antigenic in patients with heparin-induced thrombocytopenia. More comprehensive investigations will be required to determine the biological relevance of this and to establish the antibody-generation pattern in other diseases.

Adult↗
PubMed1999

Inhibition of bacterial cell wall-induced leukocyte recruitment and hepatic granuloma formation by TGF-beta gene transfer.

Intraperitoneal injection of streptococcal cell walls (SCW) into Lewis rats results in dissemination of SCW to the liver, spleen, bone marrow, and peripheral joints. The uptake of SCW by Kupffer cells in the liver initiates a chain of events largely mediated by T lymphocytes and macrophages. Local synthesis and secretion of cytokines and growth factors in response to the persistent SCW lead to the evolution and maintenance of a chronic T cell-dependent granulomatous response and result in granuloma formation and irreversible hepatic fibrosis. In an attempt to impede the development of the chronic granulomatous lesions in the liver, we injected a plasmid DNA encoding TGF-beta 1 i.m. to the SCW animals to determine the effect of TGF-beta 1 gene transfer on the course of liver inflammation and fibrosis. A single injection of plasmid DNA encoding TGF-beta 1 resulted in virtual abolition of the development of the SCW-induced hepatic granuloma formation and matrix expansion. TGF-beta 1 DNA not only reduced key proinflammatory cytokines including TNF-alpha, IL-1 beta, IFN-gamma, and IL-18, but also inhibited both CXC and CC chemokine production, thereby blocking inflammatory cell recruitment and accumulation in the liver. Moreover, TGF-beta 1 gene delivery inhibited its own expression in the liver tissue, which is otherwise up-regulated in SCW-injected animals. Our study suggests that TGF-beta 1 gene transfer suppresses hepatic granuloma formation by blocking the recruitment of inflammatory cells to the liver, and thus may provide a new approach to the control of hepatic granulomatous and fibrotic diseases.

Animals↗
PubMed1999

Direct, ultrasensitive, and selective optical detection of protein toxins using multivalent interactions.

Three highly sensitive, selective, and reagent-free optical signal transduction methods for detection of polyvalent proteins have been developed by directly coupling distance-dependent fluorescence self-quenching and/or resonant-energy transfer to the protein-receptor binding events. The ganglioside GM1, as the recognition unit for cholera toxin (CT), was covalently labeled with fluorophores and then incorporated into a biomimetic membrane surface. The presence of CT with five binding sites for GM1 causes dramatic change for the fluorescence of the labeled GM1. (1) In the scheme using fluorescence self-quenching as a signal-transduction mechanism, the fluorescence intensity drops significantly as a result of aggregation of the fluorophore-labeled GM1 on a biomimetic surface. (2) By labeling GM1 with a fluorescence energy transfer pair, aggregation of the labeled GM1 results in a decrease in donor fluorescence and an increase in acceptor fluorescence, providing a unique signature for selective protein-receptor binding. (3) In the third scheme, using the biomimetic surface as part of signal transduction and combining both fluorescence self-quenching and energy-transfer mechanisms to enhance the signal transduction, a signal amplification was achieved. The detection systems can reliably detect less than 0.05 nM CT with fast response (less than 5 min). This approach can easily be adapted to any biosensor scheme that relies on multiple receptors or co-receptors. The methods can also be applied to investigate the kinetics and thermodynamics of the multivalent interactions.

Albumins↗
PubMed1999

Advanced glycation in D-galactose induced mouse aging model.

It was first reported in China that injection of a low dose of D-galactose into mice could induce changes which resembled accelerated aging. The aging model shows neurological impairment, decreased activity of anti-oxidant enzymes, and poor immune responses. However, the underlining mechanism remains largely unknown. D-galactose is a reducing sugar that can form advanced glycation endproducts (AGE) in vivo. To investigate the role of AGE in this aging model, a group of 5-month-old C57 mice were injected daily with D-galactose, D-galactose modified AGE-lysine (AGE-lysine), L-glucose, L-lysine, or control buffer for 8 weeks. Two additional groups were treated with the AGE formation inhibitor, aminoguanidine. The results show that D-galactose, L-glucose, and AGE-lysine treated mice had a significant increase in serum AGE levels, memory latency time and error rate, and skin hydroxyproline content. Similar to aged controls, these mice also had a significant decrease in motor activity, lymphocyte mitogenesis, interleukin-2 (IL-2) production, and superoxide dismutase (SOD) enzyme activity. The aminoguanidine treated D-galactose-injected mice, however, showed no significant changes in these parameters in comparison with young controls. These data indicate that D-galactose and L-glucose form AGEs in vivo and that elevated AGEs may accelerate the aging process. The fact that both D-galactose and AGE treated mice resemble aged mice suggests that advanced glycation, at least partially, accounts for the mechanism of this aging model.

Aging↗
PubMed1999

[Effects of cooking oil fume condensate on cellular immunity and immunosurveillance in mice].

Rapeseed oil fume, soyabean oil fume and salad oil fume condensate were injected respectively to female Kunming mice. The results showed that, compared to control group, in mice exposed to low level of rapeseed oil fume condensate, the delayed hypersensitivity responses were inhibited, while in mice exposed to high level of that, the delayed hypersensitivity responses and the NK cells activity were inhibited. In mice exposed to high level of soyabean oil fume condensate the delayed hypersensitivity responses, the NK cells activity and CaM activity were inhibited. The results of these parameters were all statistically significantly different from those in control mice. In mice exposed to low level of salad oil fume condensation, the delayed hypersensitivity responses and the NK cells activity were significantly inhibited. The results indicated that cooking oil fume could affect immune system of animals.

Air Pollutants↗
PubMed1999

Mitogen-activated protein kinase is involved in the degradation of p53 protein in the bryostatin-1-induced differentiation of the acute promyelocytic leukemia NB4 cell line.

Overexpression of mutant p53 has been reported to promote tumorigenicity in several cancers. However, despite its potential importance, the signals regulating mutant p53 protein expression are not known. Here we show that a form of p53 that is incapable of binding DNA is overexpressed in the acute promyelocytic leukemia NB4 cell line. Our results demonstrate that treatment of NB4 cells with bryostatin-1, which induces differentiation in this cell line, leads to hyperphosphorylation of this DNA binding-impaired form of p53 via mitogen-activated protein kinase. After this phosphorylation, the p53 protein is degraded by the ubiquitin/proteasome pathway. Furthermore, we show that inhibition of p53 hyperphosphorylation blocks p53 protein degradation and cell differentiation. In addition, inhibition of the ubiquitin/proteasome pathway also blocks p53 protein degradation and cell differentiation. These findings suggest a role for mitogen-activated protein kinase in the degradation of the DNA binding-impaired form of p53 protein and in the bryostatin-induced differentiation observed in this cell line. The implications of these results with respect to the functional significance of p53 phosphorylation and degradation in cell differentiation are discussed.

Bryostatins↗
PubMed1999

Determination of heparin-induced IgG antibody by fluorescence-linked immunofiltration assay (FLIFA).

A fluorescence-linked immunofiltration assay (FLIFA) was developed for the determination of heparin-induced IgG in heparin-induced thrombocytopenia (HIT) type II patients. Protein A was immobilized on a nitrocellulose membrane to bind heparin-induced IgG of HIT type II patients. Fluorescein-5-isothiocynate (FITC)-heparin was added to platelet factor 4 present in normal serum to form the neo-antigen which was captured by heparin-induced IgG. The heparin-induced IgG was quantified by the relative fluorescence intensity (RFI) of bound FITC-heparin. Values were expressed as a RFI ratio (RFI patient / RFI normal) and were 1.965+/-0.413 in HIT type II patients (n = 36) and 1.064+/-0.162 in healthy controls (n = 50, p<0.0001). The intra- and inter-assay coefficients of variation were 4.9 and 10.4%, respectively. The heparin-induced IgG FLIFA will be useful in individual and epidemiological studies in patients during treatment with heparin. The FLIFA technique offers an alternative, rapid and sensitive methodological approach for studies on the interaction between antigen-antibody or ligand-receptor.

Anticoagulants↗
PubMed1999

Immunologic response to recombinant hirudin in HIT type II patients during long-term treatment.

We prospectively investigated 27 patients with heparin-induced thrombocytopenia (HIT) type II who were subsequently treated with r-hirudin. Patients with venous or arterial thromboembolism were treated with activated partial thromboplastin time (aPTT)-controlled intravenous r-hirudin (n = 19; mean 19.3 d) followed by subcutaneous r-hirudin (n = 6; mean 22.5 d) and oral anticoagulation. Patients without thromboembolism were treated with subcutaneous r-hirudin (n = 8; mean 25.9 d). Four patients were readmitted to subcutaneous r-hirudin for a mean duration of 32 d. The incidence of r-hirudin antibodies was 84% for intravenously treated patients and 50% in subcutaneously treated patients. The patients (n = 27) showed a 74% overall incidence of r-hirudin antibodies, mainly of the IgG-subclass, without seroconversion before day 6 and after day 32 of r-hirudin treatment or during r-hirudin treatment. None of the patients showed onset or recurrence of venous or arterial thromboembolism, systemic allergic reactions or IgE-antibody development. During intravenous and subcutaneous administration of r-hirudin the aPTT and the ecarin clotting time was increased in the antibody-positive patients compared to antibody-negative patients. Therefore we assume that r-hirudin antibodies may reduce r-hirudin metabolism.

Adult↗
PubMed1999

Childhood-onset primary open angle glaucoma in a Canadian kindred: clinical and molecular genetic features.

OBJECTIVE: To describe the clinical features and identify the molecular etiology of childhood-onset primary open angle glaucoma (POAG) in a Canadian kindred. METHODS: Members of a Canadian Caucasian family with POAG were examined and DNA obtained. Single-strand conformation polymorphism analysis was performed using reported primers from exon 3 of the myocilin gene. A single-stranded conformation polymorphism was characterized by polymerase chain reaction-based sequencing. RESULTS: Two affected half-sibs had onset of severe glaucoma at age 3 and 9. Their mother had lost vision in one eye from glaucoma by age 17. All three affected subjects had undergone bilateral glaucoma filtering surgery. Both fathers were unaffected. A single-stranded conformation polymorphism was identified in the mother and the two affected daughters and was absent in one father. A single base change from C-->T at nucleotide position 1109 was identified in the affected members of the family by direct sequencing. This mutation, which causes a nonconservative amino acid change (Pro370Leu), was not found on 192 normal chromosomes from Caucasian individuals. CONCLUSION: We report a Canadian family with childhood-onset, severe POAG due to a mutation in the myocilin gene.

Adult↗
PubMed1999

Studies of hydroxypropyl methylcellulose donut-shaped tablets.

Simple uncoated compressed tablets with a central hole (donut shape) or multihole tablets were prepared. Theophylline and diltiazem hydrochloride were used as model drugs to investigate in vitro drug release from donut-shaped tablets. The effects of hole size, the number of holes, drug solubility, and stirring rate on release kinetics were investigated. As for the donut-shaped tablets, the duration of zero-order drug release could be up to 80-90%. When the hole size was increased, the release rate increased, and the duration of linear drug release was longer. The durations of linear drug release of two-hole and three-hole tablets were longer than that of the single-hole tablets. As the drug solubility increased, the duration of linear drug release was shortened. However, three stirring rates (50 rpm, 100 rpm, 150 rpm) had little effect on the drug release.

Diltiazem↗