Biomedical subjects

Rong Chen

Publications and source records attributed to Rong Chen.

At least 73 records · Page 4Linked to original sources

PubMed2004

[The T-lymphocytes subsets expression in the human recurrent nasal polyps].

OBJECTIVE: To investigate the expression of T-lymphocyte subsets (CD4+, CD8+ and CD45RO+ cells) in human recurrent nasal polyps. METHOD: Nasal polyps tissue samples and peripheral blood were obtained from 17 patients, normal human inferior turbinate mucosa and peripheral blood were obtained as well. Flow cytometry was adopted to detect the expression of surface markers of the T-lymphocytes. All data were analyzed with t-test. RESULT: There were significantly large number of CD4+, and CD45RO+ cells in the tissue of recurrent nasal polyps. The expression percentage of CD3+ CD4+ cells was significantly higher than that of CD3+ CD8+ cells. Ratio of CD3+ CD4+/CD3+ CD8+ was 1.956 +/- 0.093. CONCLUSION: There were generous of T-lymphocytes expression in human recurrent nasal polyps. The ratio of the T-lymphocytes subsets was abnormal high than the usual and this indicated the immunological function were in disorder in the local area. The abnormally higher expression of CD3+ CD4+ cells in the local area may play an important role in the recurrence of human nasal polyps.

Adolescent↗

PubMed2004

[Experimental study on antioxidant and calcium channel blockade preventing testicular fibrosis in rats].

OBJECTIVE: To investigate the preventive effect of antioxidant and calcium channel blockade on testicular fibrosis in rats, and to explore the ideal drug for preventing it. METHODS: Eighty Wistar rats were divided into a control group (Group A, n = 10), a treatment group (Group B, n = 57) and a testicular fibrosis model group (Group C, n = 13). And the treatment group was further divided into a higher dosage group (Group a, n = 20), a medium dosage group (Group b, n =20) and a lower dosage group (Group c, n = 17). Testicular fibrosis was duplicated with altered Wang Tao's method. From the second day of the first immunization, the higher dosage group was given antioxidant vitamins 90 mg/(kg x d) and verapamil 50 mg/(kg x d), the medium dosage group antioxidant vitamins 90 mg/(kg x d) and verapamil 25 mg/(kg x d), and the lower dosage group antioxidant vitamins 90 mg/(kg x d) and verapamil 12.5 mg/(kg x d), all for 150 days. The control and the model groups received no treatment. The sperm count, sperm deformity rate, testis length and seminiferous tubule intradiameter were measured, and the changes of the testis interstitial substance and spermatogenic cells were observed by light microscope and transmission electron microscope. RESULTS: Testicular fibrosis was significantly prevented by the higher- and medium-dosage treatment in the rats. In the higher dosage group, the intradiameter of the seminiferous tubules and the thickness of the limiting membrane were almost the same as in the control. In the lower dosage group the thickness of the limiting membrane was thicker and the damage to the spermatogenic cells was heavier than in the control, but the pathological changes of the testis structure was lighter than in the model group, in which Hyperplasia and fibroblast increase in the interstitial substance were significant, interstitial mast cells and peritubular mast cells increased, the thickness of the limiting membrane of the seminiferous tubules seriously thickened, and the damage to the spermatogenic cells was severe. CONCLUSION: Testicular fibrosis in rats can be significantly prevented by antioxidant and calcium channel blockade.

Animals↗

PubMed2004

[Determination of four nucleosides in Banlangen injections using capillary zone electrophoresis].

The contents of cytidine, adenosine, guanosine and uridine in Banlangen Injections were determined by capillary zone electrophoresis. Shorter fused silica capillary (32.5 cm x 50 microm i. d. with effective length of 23.5 cm) was used. The samples were analyzed with 60 mmol/L borate-10% (v/v) 2-propanol-20% (v/v) acetonitrile running buffer at 20 kV voltage (25 degrees C capillary temperature). Pressure injection of 1 kPa x 10 s was employed, and the detection wavelength was 254 nm. Factors of the electrophoresis condition were investigated, such as the kinds and concentration of the electrolyte, buffer pH value, the type and concentration of organic modifier, separation voltage and temperature. The samples were filtered through 0.45 microm membrane, then direct injection was employed. External calibration of peak area versus concentration was used in the determination. Linear calibrations of four nucleosides were obtained within 12.5 - 250 mg/L (r > 0.999 1). The limits of detection (mg/L) were 6.2 of cytidine, 4.6 of adenosine, 6.7 of guanosine, and 9.0 of uridin. The average recoveries of the four nucleosides were between 95.1% - 102.3% with RSDs of 0.3% - 4.9%. The method is simple, rapid, reproducible and accurate. It can be used for the routine analysis of the four nucleosides in Banlangen Injections.

Adenosine↗

PubMed2003

[One-stage urethroplasty using colonic mucosa in the treatment of complex lengthy urethral stricture].

OBJECTIVE: To investigate the feasibility of urethral reconstruction with colonic mucosa graft in the treatment of complex lengthy urethral stricture. METHODS: Between October 2000 and May 2003, 19 male patients with complex lengthy urethral stricture that had undergone unsuccessful urethral repair 3 times on average, aged 18 - 65, were treated with free graft of colonic mucosa 10 to 17 cm (mean 13.2 cm) long. The patients were followed-up for 6 - 36 months (17 months on average) by retrograde urethrography, urethroscopy, and uroflometry. RESULTS: Meatal stenosis that needed reoperation was developed in 1 patient 3 months postoperatively. This patient became voiding very well with a urinary peak flow of 28.7 ml per second during the follow-up of 12 months after the second operation. Hyperplasia of verumontanum was observed during urethroscopy in 1 patient 14 months postoperatively. Uroflometry examination showed a urinary peak flow of 46.5 ml/s after transurethral colliculectomy. The other 17 patients were voiding well with a urinary peak flow greater than 15 ml/s (16 to 28.5 ml/s). CONCLUSION: Colonic mucosa graft urethroplasty is a feasible procedure for the treatment of complex lengthy urethral stricture, particularly when the more conventional options fail or are contraindicated.

Adolescent↗

PubMed2003

The role of exogenous testosterone in cocaine-induced behavioral sensitization and plasmalemmal or vesicular dopamine uptake in castrated rats.

The possible interaction between testosterone and cocaine on behavioral and neurochemical alterations was investigated. In castrated (CAST) rats, chronic administration of testosterone propionate (TP, 2 mg/kg, s.c.) delayed and reduced chronic cocaine-induced (24 mg/kg, i.p.) focused stereotypy sensitization measured by a force-plate actometer, while the absence of TP was associated with robust behavioral sensitization to cocaine. TP itself did not produce focused stereotypy. Postmortem assays revealed that TP administration to CAST rats partially, but significantly, restored the cocaine-induced reduction of striatal plasmalemmal dopamine (DA) uptake compared to CAST rats without TP. In contrast, TP treatment did not significantly differ from the oil treatment of CAST rats in cocaine-associated enhancement of vesicular DA uptake. Thus, testosterone may modulate cocaine-induced alteration of homeostasis between extracellular and cytosolic DA pools, which may play a role in behavioral sensitization.

Animals↗

PubMed2003

RDOCK: refinement of rigid-body protein docking predictions.

We present a simple and effective algorithm RDOCK for refining unbound predictions generated by a rigid-body docking algorithm ZDOCK, which has been developed earlier by our group. The main component of RDOCK is a three-stage energy minimization scheme, followed by the evaluation of electrostatic and desolvation energies. Ionic side chains are kept neutral in the first two stages of minimization, and reverted to their full charge states in the last stage of brief minimization. Without side chain conformational search or filtering/clustering of resulting structures, RDOCK represents the simplest approach toward refining unbound docking predictions. Despite its simplicity, RDOCK makes substantial improvement upon the top predictions by ZDOCK with all three scoring functions and the improvement is observed across all three categories of test cases in a large benchmark of 49 non-redundant unbound test cases. RDOCK makes the most powerful combination with ZDOCK2.1, which uses pairwise shape complementarity as the scoring function. Collectively, they rank a near-native structure as the number-one prediction for 18 test cases (37% of the benchmark), and within the top 4 predictions for 24 test cases (49% of the benchmark). To various degrees, funnel-like energy landscapes are observed for these 24 test cases. To the best of our knowledge, this is the first report of binding funnels starting from global searches for a broad range of test cases. These results are particularly exciting, given that we have not used any biological information that is specific to individual test cases and the whole process is entirely automated. Among three categories of test cases, the best results are seen for enzyme/inhibitor, with a near-native structure ranked as the number-one prediction for 48% test cases, and within the top 10 predictions for 78% test cases. RDOCK is freely available to academic users at http://zlab.bu.edu/ approximately rong/dock.

Algorithms↗

PubMed2003

ZDOCK predictions for the CAPRI challenge.

The CAPRI Challenge is a blind test of protein-protein-docking algorithms that predict the complex structure from the crystal structures of the interacting proteins. We participated in both rounds of this blind test and submitted predictions for all seven targets, relying mainly on our Fast Fourier Transform based algorithm ZDOCK that combines shape complementarity, desolvation, and electrostatics. Our group made good predictions for three targets and had at least some success with three others. Implications of the treatment of prior biological information as well as contributions of manual inspection to docking predictions are also discussed.

Algorithms↗

PubMed2003

ZDOCK: an initial-stage protein-docking algorithm.

The development of scoring functions is of great importance to protein docking. Here we present a new scoring function for the initial stage of unbound docking. It combines our recently developed pairwise shape complementarity with desolvation and electrostatics. We compare this scoring function with three other functions on a large benchmark of 49 nonredundant test cases and show its superior performance, especially for the antibody-antigen category of test cases. For 44 test cases (90% of the benchmark), we can retain at least one near-native structure within the top 2000 predictions at the 6 degrees rotational sampling density, with an average of 52 near-native structures per test case. The remaining five difficult test cases can be explained by a combination of poor binding affinity, large backbone conformational changes, and our algorithm's strong tendency for identifying large concave binding pockets. All four scoring functions have been integrated into our Fast Fourier Transform based docking algorithm ZDOCK, which is freely available to academic users at http://zlab.bu.edu/~ rong/dock.

Algorithms↗

PubMed2003

A protein-protein docking benchmark.

We have developed a nonredundant benchmark for testing protein-protein docking algorithms. Currently it contains 59 test cases: 22 enzyme-inhibitor complexes, 19 antibody-antigen complexes, 11 other complexes, and 7 difficult test cases. Thirty-one of the test cases, for which the unbound structures of both the receptor and ligand are available, are classified as follows: 16 enzyme-inhibitor, 5 antibody-antigen, 5 others, and 5 difficult. Such a centralized resource should benefit the docking community not only as a large curated test set but also as a common ground for comparing different algorithms. The benchmark is available at (http://zlab.bu.edu/~rong/dock/benchmark.shtml).

Algorithms↗

PubMed2003

Behavioral sensitization to amphetamine in rats: changes in the rhythm of head movements during focused stereotypies.

RATIONALE: The indirect-acting dopamine agonist amphetamine induces in rats, motor stereotypies that have served as the primary behavioral end points in studies related to schizophrenia, drug abuse, and L-dopa-induced dyskinesias. Despite the experimental importance of this rodent response to this drug, little is known about the rhythmic character of the behavior and how such rhythms change (or sensitize) in response to repeated treatment with amphetamine. OBJECTIVE: To address this lack of quantitative information, the rhythms of focused stereotypies (characterized by a lack of locomotion and rapid head movements) were measured in a force-plate actometer that permitted the quantification of behavioral rhythmicity. METHODS: Focused stereotypies were induced by d-amphetamine sulfate (2.5 and 5.0 mg/kg) after acute and repeated treatment with fixed doses of the drug in separate groups of rats, and the drug-induced behaviors were recorded in 1-h sessions in the actometer. RESULTS: The two doses of amphetamine produced focused stereotypies characterized by a 10-Hz rhythm of head movements. Detailed analyses of the data for 5.0 mg/kg amphetamine showed that the rhythm in the 10-Hz region of the power spectrum increased significantly within a 1-h period, while five intermittent, repeated drug treatments significantly reduced the rhythm, possibly reflecting either tolerance or sensitization. CONCLUSIONS: Aside from providing a new quantitative approach to studying focused stereotypies, these observation direct attention to the possibility that practice-mediated processes involved in motor skill enhancement may be a part of the neural adaptations that parallel the development of sensitization to indirect-acting dopamine agonists.

Amphetamine↗

PubMed2003

A novel shape complementarity scoring function for protein-protein docking.

Shape complementarity is the most basic ingredient of the scoring functions for protein-protein docking. Most grid-based docking algorithms use the total number of grid points at the binding interface to quantify shape complementarity. We have developed a novel Pairwise Shape Complementarity (PSC) function that is conceptually simple and rapid to compute. The favorable component of PSC is the total number of atom pairs between the receptor and the ligand within a distance cutoff. When applied to a benchmark of 49 test cases, PSC consistently ranks near-native structures higher and produces more near-native structures than the traditional grid-based function, and the improvement was seen across all prediction levels and in all categories of the benchmark. Without any post-processing or biological information about the binding site except the complementarity-determining region of antibodies, PSC predicts the complex structure correctly for 6 test cases, and ranks at least one near-native structure in the top 20 predictions for 18 test cases. Our docking program ZDOCK has been parallelized and the average computing time is 4 minutes using sixteen IBM SP3 processors. Both ZDOCK and the benchmark are freely available to academic users (http://zlab.bu.edu/~ rong/dock).

Binding Sites↗

PubMed2003

Multifunctional Alloys Obtained via a Dislocation-Free Plastic Deformation Mechanism.

We describe a group of alloys that exhibit "super" properties, such as ultralow elastic modulus, ultrahigh strength, super elasticity, and super plasticity, at room temperature and that show Elinvar and Invar behavior. These "super" properties are attributable to a dislocation-free plastic deformation mechanism. In cold-worked alloys, this mechanism forms elastic strain fields of hierarchical structure that range in size from the nanometer scale to several tens of micrometers. The resultant elastic strain energy leads to a number of enhanced material properties.

Journal Article↗

PubMed2003

Marked variation in clinical presentation and age of onset in a family with a heterozygous parkin mutation.

Parkin gene mutations have been detected in families with early-onset autosomal recessive parkinsonism. We report a novel heterozygous 40 base pair deletion in exon 3 of the parkin gene that increases the susceptibility of carriers to develop parkinsonism/dystonia and manifests remarkable variability in regard to age of onset and phenotype in a single family. After identifying the new mutation in the proband of this kindred, family members were contacted and evaluated by a movement disorders specialist using standardized protocols and prospectively set diagnostic criteria. Importantly, examining physicians and family members were blinded to the genetic testing. Five affected members in two generations carried the parkin mutation. The proband and one of his brothers had disease onset at 24 years of age while another brother had disease at age 44. One exhibited multi-focal dystonia and parkinsonism of 17 years duration, another suffered a unilateral slowly progressive parkinsonism over 13 years while the third suffered dystonia-parkinsonism of recent onset. A sibling pair in the preceding generation had mild previously undiagnosed parkinsonism. Clinicians should be aware that patients carrying a parkin gene mutation may present with dystonia-parkinsonism or very subtle parkinsonism with a markedly varied age of onset.

Adult↗

PubMed2003

Crystallization and preliminary crystallographic analysis of San Miguel sea lion virus: an animal calicivirus.

The Caliciviridae is a family of nonenveloped, icosahedral, positive-sense single-stranded RNA viruses. This family of viruses consists of both animal and human pathogens. Adapting human caliciviruses to cell culture has not been successful, whereas some animal caliciviruses, including San Miguel sea lion virus, have been successfully propagated in vitro. Here we report the crystallization of San Miguel sea lion virus serotype 4 (SMSV4) and the preliminary X-ray crystallographic analysis of the crystals. SMSV4 have been crystallized using the hanging-drop method. These crystals diffracted to approximately 3A resolution using a synchrotron radiation source. A single crystal under cryo-conditions yielded a complete set of diffraction data. Data processing of the diffraction patterns showed that SMSV crystals belong to I23 space group with cell dimensions a=b=c=457 A. The crystallographic asymmetric unit includes five icosahedral asymmetric units, each consisting of three capsid protein subunits. In the space group I23, given the icosahedral symmetry and the size of the virus particle, the location of the particle is constrained to be at the point where the crystallographic 2- and 3-fold axes intersect. The orientation of the virus particle in the unit cell was ascertained by self-rotation function calculations.

Capsid↗

PubMed2003

One-stage urethral reconstruction using colonic mucosa graft: an experimental and clinical study.

AIM: To investigate the possibility of urethral reconstruction with a free colonic mucosa graft and to present our preliminary experience with urethral substitution using a free graft of colonic mucosa for treatment of 7 patients with complex urethral stricture of a long segment. METHODS: Ten female dogs underwent a procedure in which the urethral mucosa was totally removed and replaced with a free graft of colonic mucosa. A urodynamic study was performed before the operation and sacrifice. The dogs were sacrificed 8 to 16 weeks after the operation for histological examination of urethra. Besides, 7 patients with complex urethral stricture of a long segment were treated by urethroplasty with the use of a colonic mucosal graft. The cases had undergone an average of 3 previous unsuccessful repairs. Urethral reconstruction with a free graft of colonic mucosa ranged from 10 to 17 cm (mean 13.1 cm). Follow-up included urethrography, urethroscopy and uroflowmetry. RESULTS: Urethral stricture developed in 1 dog. The results of urodynamic studies showed that the difference in the maximum urethral pressure between the pre-operation and pre-sacrifice in the remaining 9 dogs was not of significance (P>0.05). Histological examination revealed that the colonic free mucosa survived inside the urethral lumen of the 10 experimental dogs. Plicae surface and unilaminar cylindric epithelium of the colonic mucosa was observed in dogs sacrificed 8 weeks after the operation. The plicae surface and unilaminar cylindric epithelium of the colonic mucosa was not observed, and metaplastic transitional epithelium covered a large proportion of the urethral mucosa in dogs sacrificed 12 weeks after the operation. Clinically, the patients were followed up for 3-18 months postoperatively (mean 8.5 months). Meatal stenosis was developed in 1 patient 3 months postoperatively and needed reoperation. The patient was voiding very well with urinary peak flow 28.7 ml/s during the follow-up of 9 months after reoperation. The other patients were voiding well with urinary peak flow greater than 15 ml/s. Urethrogram revealed a patent urethra with an adequate lumen with no significant graft sacculation. Neither necrosis of neourethral mucosa nor stenosis at the anastomosis sites has been observed on urethroscopy in 4 patients over 6 months after operation. CONCLUSION: Urethral mucosa can be replaced by colonic mucosa without damaging the continence mechanism in female dogs. Colonic mucosa graft urethral substitution is a feasible procedure for the treatment of complex urethral stricture of a long segment. The technique may be considered when more conventional options have failed or are contraindicated.

Adult↗

PubMed2003

Response of antioxidase in viscera of Pagrosuma major larvae to water soluble fraction of hydrocarbons in No.0 diesel oil.

Pagrosomus major larvae were exposed to the water-soluble fraction of hydrocarbon in No.0 diesel oil (corresponding to No.2 fuel oil) at concentrations of 0, 0.17, 1.22 and 8.82 mg/L for up to 15 days. Larvae were sampled on days 9 and 15 of the experiment. Supernatants of viscera tissue extractions were assayed for biochemical response in terms of oxidative stress-superoxide dismutase(SOD), activity of selenium-dependant glutathione peroxidase(Se-GPx) and catalase (Ca), and the concentration of reduced glutathione (GSH). On day 9 of exposure, statistically significant dose-related increases in Se-GPx and SOD activity, and GSH concentration were ohserved in all cases except for Se-GPx activity under the highest dosage of hydrocarbon. However, on day 15 of exposure, a similar dose-related response was only observed for Se-GPx activity. GSH concentration decreased and SOD activity showed no statistical difference as compared to controls. However, a significant decrease in compared to day 9 Se-GPx activity and GSH concentration, in contrast to increase SOD activity at day 15 as indicates an accelerated accumulation of H2O2 and potential oxidative damage under long-term exposure of larvae to hydrocarbons. No statistical changes were observed in Ca activity throughout the experiment, possibly owing to the high efficiency of Se-GPx. A recovery experiment was performed on indicating that the response of antioxidants measured tending to return to their control levels. These results prove the function of the antioxidant defense system of the larvae to the water-soluble fraction of hydrocarbons in No.0 diesel oil.

Animals↗

PubMed2003

[Simultaneous determination of tryptophan and tyrosine in injection by artificial neural network and fluorescence spectrum method].

A new fluorescence method by artificial neural network for the simultaneous determination of tryptophan and tyrosine was developed. The determination was carried out in the KH2PO4-K2HPO4 buffer solution (pH = 7.15) and at the EX (excitation) wavelength of 224 nm. In the range of 290-400 nm, the fluorescence intensities at fourteen wavelengths were taken as characteristic parameters of the artificial neural network, and the samples were arranged by the method of equality design. The mean recoveries of tryptophan and tyrosine were 100.9% and 101.6% respectively. The RSDs of the results were 4.18% and 4.17%. The method has been applied to the determination of tryptophan and tyrosine in compound amino acid injection, and the relative errors were 4.0% and 2.6%, respectively. The results were better than those of other networks in training speed and accuracy. In conclusion, the new network spectrofluorimetry is a good choice for multicomponent resolving analysis.

Amino Acids↗

PubMed2002

Screening of ferritin light polypeptide 460-461InsA mutation in Parkinson's disease patients in North America.

An insertional (460-461InsA) mutation in the ferritin light polypeptide (FTL) gene was recently reported in some patients with a familial form of basal ganglia degeneration with varying extrapyramidal manifestations. Some of the affected family members presented with a phenotype indistinguishable from typical Parkinson's disease (PD). In this study, 253 patients with a clinical diagnosis of idiopathic PD were screened for the insertion in the FTL gene by polymerase chain reaction-restriction fragment length polymorphism method. The results showed that none of them had the mutation, indicating that genetic defects in the FTL gene are unlikely to be a common cause of typical PD, at least in a North America population.

DNA Mutational Analysis↗