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Biomedical subjects

Ming Chen

Publications and source records attributed to Ming Chen.

At least 145 records · Page 8Linked to original sources
PubMed2003

Bcl10 protein can act as a transcription activator in yeast.

The Bcl10 gene has recently been cloned from the chromosomal translocation t(1:14) (p22; q32) in a low-grade mucosa-associated lymphoid tissue (MALT) lymphoma, and was implicated in the pathogenesis of this and several other tumor types. In yeast two hybrid systems, when it was fused to Gal4 DNA-binding domain of pGBT9, this fusion protein can activate the expression of reporter genes without Gal4-AD domain. Through deletion assay and secondary structure prediction, we found that the N-terminal of Bcl10 contributed more to activation than the C-terminal. It has been recently reported that Bcl10 expression is correlated with the activation of NF-kappaB in eukaryotic cells, so it may represent an important role in protein expression. Our research is the first to demonstrate a new function of Bcl10: transcription activation in yeast.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Male genital schwannoma, review of 5 cases.

AIM: To study the clinical features of male genital schwannoma. METHODS: Five male patients with genital schwannoma admitted from 1991 to 2000 were reviewed. The lesions were located in the prostate, spermatic cord, testis or penis. Tumors were simply resected in 3 patients and radically eradicated in 2. RESULTS: The average age of the cohort was 37 years. The most common sign at presentation was a palpable genital mass accidentally discovered by the patient or detected by the physician during a physical check. Diagnosis was made through postoperative pathological examination. Follow-up ranged from 2 years to 6 years (mean 4.5 years). Four cases were cured by simple excision and 1 patient with malignant testis schwannoma died of recurrence 1 year after surgery. CONCLUSION: Owing to the lack of characteristic clinical manifestation, the final diagnosis relies on postoperative pathological examination. S-100 and vimentin are useful markers for the diagnosis of these tumors.

Adult↗
PubMed2003

Quantitative Petri net model of gene regulated metabolic networks in the cell.

A method to exploit hybrid Petri nets (HPN) for quantitatively modeling and simulating gene regulated metabolic networks is demonstrated. A global kinetic modeling strategy and Petri net modeling algorithm are applied to perform the bioprocess functioning and model analysis. With the model, the interrelations between pathway analysis and metabolic control mechanism are outlined. Diagrammatical results of the dynamics of metabolites are simulated and observed by implementing a HPN tool, Visual Object Net ++. An explanation of the observed behavior of the urea cycle is proposed to indicate possibilities for metabolic engineering and medical care. Finally, the perspective of Petri nets on modeling and simulation of metabolic networks is discussed.

Algorithms↗
PubMed2003

[Cardiac presentations in patients with SARS].

OBJECTIVE: To investigate the impact of SARS on heart initially. METHODS: The clinical and laboratory data of 86 patients with SARS were collected and analyzed statistically. RESULTS: In recovery phase, the rest heart rates in 64% of patients with SARS exceeded 90 bpm, and the heart rates after mild exercises in 72.1% of patients with SARS exceeded 100 bpm. CONCLUSION: SARS, which mainly resulted in pulmonary damage, may involve heart.

Heart Rate↗
PubMed2003

[Studies on sexual dysfunction in male patients with chronic renal insufficiency].

OBJECTIVES: To investigate the prevalence, main manifestation and related factors of sexual dysfunction in male patients with chronic renal insufficiency (CRI). METHODS: A cross-section study was conducted by six hospitals in Sichuan Province. The prevalence and severity of sexual dysfunction were assessed by SCASF microsoft among patients with chronic renal disease. Logistic regression was used to examine and test the association between sexual dysfunction and other medical conditions. RESULTS: The prevalence of sexual dysfunction was wider in patients with CRI than in those without. The main manifestations in male patients were decreased libido, erectile dysfunction and premature ejaculation. Stratified analysis in uremia showed that the prevalence and severity of sexual dysfunction were similar between patients on haemodialysis(HD) and those on peritoneal dialysis(PD). The patients receiving no replacement treatment suffered more decreased libido and performance anxiety than dialyzed patients (HD and PD) and transplantation patients(Tx). The patients receiving no replacement treatment and dialysis suffered more erectile dysfunction than Tx men. A multivariable analysis demonstrated that the duration, creatinine clearance(Ccr), parathyroid hormone (PTH), albumin(Alb) were not associated with sexual dysfunction. The use of beta-blocker, anemia and depression were risky factors for decreased libido, and increasing age was a risky factor for erectile dysfunction. The use of angiotensin-converting-enzyme inhibitor(ACEI)/angiotention receptor antagonist (ARB) and recombinant human erythropoietin(r-HuEpo) were protective factors for erectile dysfunction. CONCLUSIONS: The main manifestations of sexual dysfunction in male patients with CRI are decreased libido, erectile dysfunction and premature ejaculation. The replacement therapy, especially transplantation, can decrease the prevalence or severity of sexual dysfunction. The genesis of sexual dysfunction is multifactorial, including age, physiological factors, psychological factors and medical conditions.

Adult↗
PubMed2003

[Spectral analysis of electromyography of low back muscle fatigue induced by simulated driving].

OBJECTIVE: To evaluate the effects of different vibration frequency on the back muscle fatigue during simulated driving. METHODS: Thirty-six subjects performed three simulated driving experiments under three vertical vibration frequencies which were 1.8, 4.0, 6.0 Hz respectively and the driving time was 90 minutes. At the same time the electromyography of low back was recorded. RESULTS: The median frequencies calculated from the power spectrum were decreased exponentially under three vertical vibration frequencies, especially under 4.0 Hz vibration frequency. CONCLUSION: The 4.0 Hz vibration frequency has the most important effect on the back muscle fatigue under simulated driving condition.

Adult↗
PubMed2002

Impacts of phosphate amendments on lead biogeochemistry at a contaminated site.

Soil amendments can be used to cost-effectively reduce the bioavailability and mobility of toxic metals in contaminated soils. In this study a field demonstration was conducted at a Pb-contaminated site to evaluate the effectiveness of P-induced Pb immobilization. Phosphate was applied at a 4.0 molar ratio of P to Pb with three treatments: T1, 100% of P from H3PO4; T2, 50% P from H3PO4 + 50% P from Ca(H2PO4)2; and T3, 50% P from H3PO4 + 5% phosphate rock. Phosphate amendments effectively transformed soil Pb from the nonresidual (sum of exchangeable, carbonate, Fe/Mn, and organic) to the residual fraction, with residual Pb increase by 19-48% for T1, 22-50% for T2, and 11-55% for T3, respectively. Lead immobilization was attributed to the P-induced formation of chloropyromorphite [Pb10(PO4)6Cl2], which was identified in the surface soil, subsurface soil, and plant rhizosphere soil. Occurrence of chloropyromorphite was evident 220 days after P addition for T1 and T2 treatments and 330 days for T3. Visual MINTEQ model and activity-ratio diagram indicated that lead phosphate minerals controlled Pb2+ activities in the P-treated soils. Phosphate treatments significantly reduced Pb translocation from the roots to the shoots in the St. Augustine grass (Stenotaphrum secundatum), possibly via the formation of chloropyromorphite on the cell walls of roots. This field observation suggested that P amendments are efficient in reducing Pb mobility via in situ formation of insoluble chloropyromorphite minerals at a field setting. Lead immobilization shows a long-term stability. A mixture of H3PO4 and phosphate rock yields the best overall results for in situ Pb immobilization, with less soil pH change and less P leaching. Application of combined H3PO4 with phosphate rock may provide an effective alternative to the current phosphate remediation technologies for contaminated soils.

Calcium↗
PubMed2002

Effect of magnitopuncture on sympathetic and parasympathetic nerve activities in healthy drivers--assessment by power spectrum analysis of heart rate variability.

The object of this study was to assess the effects of magnitopuncture applied to Dazhui (DU14) point and Neiguan (PC6) points on sympathetic and parasympathetic nerve activities by power spectrum analysis of heart rate variability in healthy drivers during simulated driving. Using power spectrum analysis, the low frequency (LF) and high frequency (HF) components of heart rate variability can be calculated reflecting the sympathetic and parasympathetic activity. The 40 healthy male subjects were randomly divided into two groups: A (study group) and B (control group). All subjects were required to be well rested before the experiment. The subjects of both groups were required to perform a simulated driving task for 3 h. During the driving, magnitopunctures were applied to the DU14 and PC6 points for A while the subject performed the task for 2.5 h, and for B magnitopunctures were applied to non-acupuncture points which were 1.5 cm away from the two acupuncture points respectively over the same time. Subjective response to a questionnaire was obtained after the simulated task in the two groups. At the end of the driving task the LF component in normalized units (NU) had decreased significantly ( P<0.05) indicating a reduced sympathetic nerve activity and the HF component (NU) increased significantly ( P<0.05) indicating a increased parasympathetic nerve activity for A compared with pre-stimulation while for B no significant differences were observed. There were significant group differences in LF (NU), HF (NU) and LF:HF at the end of the driving task ( P<0.05). It was concluded that a modulating effect of magnitopuncture on sympathetic and parasympathetic nerve activities in healthy subjects was associated with the acupuncture points. The findings represent physiological evidence that magnitopuncture may reduce mental fatigue in healthy drivers.

Acupuncture↗
PubMed2002

Pro-apoptotic actions of exisulind and CP461 in SW480 colon tumor cells involve beta-catenin and cyclin D1 down-regulation.

Exisulind and its analogues are inhibitors of cyclic GMP phosphodiesterases (PDEs) that have been shown to activate and induce protein kinase G, resulting in the induction of apoptosis in colon cancer cells. These drugs also reduce beta-catenin protein levels and decrease cyclin D1 mRNA levels in SW480 cells. Herein we report on studies pertaining to exisulind regulation of beta-catenin levels and activity in colon tumor cells. Exisulind and its higher-affinity PDE analogues, (Z)-5-fluoro-2-methyl-(4-pyridylidene)-3-(N-benzyl)-indenylacetamide hydrochloride (CP461) and (Z)-1H-indene-3-acetamide, 5-fluoro-2-methyl-N-(phenylmethyl)-1-[(3,4,5-trimethoxyphenyl)methylene] (CP248), reduced beta-catenin, including the nuclear beta-catenin in SW480 cells (EC(50) approximately 200 microM, 1 microM, and <1 microM, respectively). The 50% reduction of beta-catenin was seen in 8-14 hr. There was no change in beta-catenin mRNA. Exisulind-induced beta-catenin reduction was blocked by the proteasomal inhibitor MG132 (Z-leu-Leu-Leu-CHO), indicating that the effect of exisulind involved ubiquitin-proteasomal degradation. A consequence of reduced beta-catenin in SW480 cells was that exisulind, CP461, and CP248 caused a concentration- and time-dependent decrease in cyclin D1 levels (EC(50) approximately 300 microM, 1 microM, and <1 microM, respectively) in 4 hr. The effect was via decreased cyclin D1 mRNA levels. Exisulind-induced degradation of beta-catenin was not blocked by the inhibition of caspase-3 activity and/or apoptosis, and some SW480 cells showed a reduction in beta-catenin levels before the appearance of early apoptosis indicators. Expression of the N-terminal 170 amino acid fragment of beta-catenin reduced the effects of beta-catenin degradation, cyclin D1 reduction, and the apoptosis response to exisulind. These results indicate that exisulind-induced beta-catenin degradation precedes the induction of apoptosis and that the down-regulation of inappropriate beta-catenin-activated genes accounts in part for the pro-apoptotic effects of exisulind and CP461 in colon tumor cells.

Adenomatous Polyposis Coli↗
PubMed2002

Synthesis of light harvesting polymers by RAFT methods.

Polymers prepared by RAFT polymerisation containing acenaphthyl energy donors and a terminal anthryl energy acceptor have a narrow molecular weight distribution and exhibit excitation energy transfer efficiencies up to 70%.

Journal Article↗
PubMed2002

Bioluminescence of Aequorea macrodactyla, a common jellyfish species in the East China Sea.

Studies of the bioluminescent mechanisms of jellyfish have been mainly confined to one species, Aequorea victoria. We describe the luminescent system of another species, Aequorea macrodactyla, which is commonly found in the warmer waters on the coastal region of East China Sea. The luminescent system of this species consists of a green fluorescent protein (GFP) and one or more aequorins. The GFP gene is 1042 bp. It encompasses a coding sequence of 717 bp organized as 3 exons, and it is predicted to specify a 27-kDa peptide, which shares 80% amino acid sequence identity with the GFP of A. victoria. The entire coding sequence was cloned into the pTO-T7 expression vector and expressed in Escherichia coli. Compared with GFP of A. victoria, the purified expressed protein exhibited an excitation peak at a higher wavelength of 476 nm and an emission peak at a lower wavelength of 496 nm, with a higher quantum yield of 1.0. The other photoprotein, aequorin, is encoded in a single open reading frame of 585 bp specifying a 23-kDa apoprotein. The gene was cloned in to the same expression vector and expressed in E. coli. The activity of the photoprotein was reconstituted by incubating the expressed apoprotein with coelenterazine f. In the presence of Ca(2+) the reconstituted aequorin exhibits an emission peak at 470 nm. The kinetics of regeneration and the photoactivities of the reconstituted aequorins of the 2 species of jellyfish are similar. Nevertheless, Aequorea macrodactyla is expected to appear brighter and more "blue" than Aequorea victorea because of the differences in the photoactivity of their GFPs.

Journal Article↗
PubMed2002

Nizatidine and omeprazole enhance the effect of metronidazole on Helicobacter pylori in vitro.

Treatment failures are common in patients infected with metronidazole-resistant Helicobacter pylori in the gastric mucosa when triple therapy including metronidazole is used. In patients with treatment failure and metronidazole-resistant H. pylori, a higher eradication rate for H. pylori was found after secondary treatment with bismuth/ranitidine in combination with antibiotics including metronidazole, compared with the same antibiotics combined with a standard dose of omeprazole. This agrees with our previous finding that bismuth was able to reduce the susceptibility of H. pylori to metronidazole. In this study, we have found that nizatidine, an H(2)-receptor antagonist, is also able to reduce the susceptibility of H. pylori to metronidazole in vitro, despite having no direct inhibitory effect on the growth of H. pylori. This agrees with earlier findings that compounds having the ability to reverse antibiotic resistance do not necessarily have an antibiotic or chemotherapeutic effect in the sense of growth inhibition. Therefore, it was decided to investigate the effect of nizatidine and omeprazole on the oxidative respiratory chain, as it is known that metronidazole is able to inhibit the activity of fumarate reductase of H. pylori. This enzyme is a key enzyme in the alternative respiratory chain under anaerobic conditions. Nizatidine was, in these preliminary experiments, found to inhibit fumarate reductase in a dose-dependent way, like metronidazole, whereas omeprazole had almost no effect on fumarate reductase. No other significant effects on the enzymes of the respiratory chain were found. The synergistic effect of nizatidine on metronidazole resistant H. pylori strains could be explained by the effect on fumarate reductase, whereas the effect of omeprazole is different and could be an inhibition of a proton pump in H. pylori. Reversal of antimicrobial resistance with the help of different non-antibiotics seems to be possible by using quite different compounds, and is therefore to be explained by different molecular mechanisms.

Anti-Bacterial Agents↗
PubMed2002

In vitro antimycobacterial and antilegionella activity of licochalcone A from Chinese licorice roots.

Licochalcone A, extracted and purified from Chinese licorice roots, showed in vitro inhibitory effect on human pathogenic Mycobacteria species and Legionella species. M. tuberculosis, M. bovis and BCG were inhibited by < 20 mg/l licochalcone A, whereas all non- M. tuberculosis complex species were resistant to > 20 mg/l Legionella pneumophila (serogroups 1 - 7) and L. bozemanii, L. dumoffii, L. feelei, L. longbeacheae and L. wadsworthii were inhibited by licochalcone A 1 - 4 mg/l, whereas L. gormanii and L. micdadei were inhibited by licochalcone A 500 - 1000 mg/l. These data indicate that licochalcone A might be of interest as a new class of antibacterial drug in the treatment of severe lung-infections.

Anti-Bacterial Agents↗
PubMed2002

Mechanism of lovastatin-induced apoptosis in intestinal epithelial cells.

We earlier showed that lovastatin potentiated the chemopreventive effects of sulindac against colon neoplasia in a rodent model and augments apoptosis induced by 5-FU and cisplatin in human colon cancer cells. In the present study, we investigated effects of lovastatin in spontaneously immortalized rat intestinal epithelial cells, IEC-18 and their K-ras transformed clones. Lovastatin induced morphologic changes (cell rounding and detachment) and apoptosis that were not influenced by K-ras mutations, but were prevented by geranylgeranyl-pyrophosphate or by mevalonate. Clostridium difficile toxin B, which directly inactivates rho, induced similar morphologic changes and apoptosis. Cycloheximide prevented these effects of lovastatin, but not C. difficile toxin B. Lovastatin decreased the amounts of membrane bound rhoA and rhoB. Cycloheximide and geranylgeranyl-pyrophosphate prevented lovastatin induced morphologic changes and apoptosis but did not inhibit lovastatin-induced changes in membrane translocation of rho. Our data suggest that lovastatin induces morphologic changes and apoptosis by inhibiting geranylgeranylation of small GTPases of the rho family and thereby inactivating them. Restoration of membrane translocation of rho is not necessary for preventing lovastatin-induced morphologic changes or apoptosis.

Animals↗
PubMed2002

Prognostic factors for local control in non-small-cell lung cancer treated with definitive radiation therapy.

Radiotherapy plays an important role as a treatment for locally advanced non-small-cell lung cancer (NSCLC), but local failure still occurs in 70% to 80% of the patients. A retrospective analysis was carried out to evaluate the local control predictors for non-SCLC. From January 1990 to December 1996, 256 patients with stages I-IIIb NSCLC entered this analysis. All patients received definitive radiotherapy. The significance of prognostic variables on local control was evaluated using univariate analysis and Cox stepwise regression model. The prognostic index was calculated according to the value of each prognostic factor on local control. Median local progression-free survival time of the whole group was 9.7 months, and 1-, 3-, and 5-year actuarial local progression-free survival were 54%, 24%, and 19%, respectively. Univariate and multivariate analyses showed patients with smaller tumor volume, earlier clinical staging, and treated with higher total dose in shortened overall treatment time had better local control. Tumor volume, clinical staging, and radiotherapy methods were independent prognostic factors on local control. The prognostic index model could predict the local control condition of NSCLC treated with radiation therapy more effectively than a single variable such as TNM staging.

Adult↗
PubMed2002

Ureaplasma urealyticum induces apoptosis in human lung epithelial cells and macrophages.

Chronic lung disease (CLD) of prematurity remains a significant cause of morbidity among premature infants. It is a multifactorial disorder and characterized by an early increased number of neutrophils and alveolar macrophages, with later architectural epithelial and endothelial cell damage. Recently, apoptosis of type 2 pneumocytes in the lung of preterm neonates with acute and chronic lung disease has been examined and apoptosis of mesenchymal cells was detected in the chronic stage of bronchopulmonary dysplasia. Infection and inflammatory responses in the lungs play important roles. However, the contribution of Ureaplasma urealyticum to the development of CLD is debated. We found that U. urealyticum induced apoptosis in human type II lung epithelial cells (A549 cell line) and macrophages (derived from human monocytic cell line THP-1) by measuring the outer leaflets translocation of phosphatidylserine (flow cytometry analysis and fluorescence microscopy assessment), DNA fragmentation analysis, cell morphology changes such as diminution in cell volume, increased cytoplasmic staining, and nuclear pyknosis (hematoxylin and eosin staining) and viable counting (trypan blue exclusion). Anti-TNF-alpha monoclonal antibody partially protected the macrophages from undergoing apoptosis after infection with U. urealyticum. Our findings imply that U. urealyticum might be involved in impairing lung structure and host immune response during the development of CLD.

Antibodies, Monoclonal↗
PubMed2002

Implications of amyloid precursor protein and subsequent beta-amyloid production to the pharmacotherapy of Alzheimer's disease.

Alzheimer's disease is the most common type of dementia in older people. It is highly prevalent, affecting 35-45% of those aged 85 years or older. This disease has devastating consequences to patients, their families, caregivers, and the health care system. Much has been learned about its pathobiology, which has led to the beta-amyloid (Abeta) hypothesis. This hypothesis continues to be the predominant postulate of the pathobiology of Alzheimer's disease. Under this hypothesis, abnormal accumulation of Abeta is followed by a cascade of neurotoxic effects, which eventually result in neurodegeneration and development of Alzheimer's disease. This is thought to be the result of altered processing of the amyloid precursor protein (APP), preferentially by beta- and gamma-secretase enzymes rather than nonamyloidogenic processing by alpha-secretase. The growing body of knowledge regarding the processing of APP to various forms of Abeta has resulted in new approaches to the investigation of putative anti-Alzheimer's disease compounds, including immune-based therapies and various agents that can positively affect APP processing.

Alzheimer Disease↗