Search PubMed⌕ Search

Biomedical subjects

Ming Chen

Publications and source records attributed to Ming Chen.

At least 37 records · Page 2Linked to original sources
PubMed2006

BNArray: an R package for constructing gene regulatory networks from microarray data by using Bayesian network.

UNLABELLED: BNArray is a systemized tool developed in R. It facilitates the construction of gene regulatory networks from DNA microarray data by using Bayesian network. Significant sub-modules of regulatory networks with high confidence are reconstructed by using our extended sub-network mining algorithm of directed graphs. BNArray can handle microarray datasets with missing data. To evaluate the statistical features of generated Bayesian networks, re-sampling procedures are utilized to yield collections of candidate 1st-order network sets for mining dense coherent sub-networks. AVAILABILITY: The R package and the supplementary documentation are available at http://www.cls.zju.edu.cn/binfo/BNArray/.

Algorithms↗
PubMed2006

Methotrexate induces cell swelling and necrosis in renal tubular cells.

BACKGROUND: The present study was carried out to investigate if methotrexate (MTX) has a direct lethal effect in renal tubular cells, and if so, to further clarify the mechanisms of cell death. MATERIALS AND METHODS: Renal tubular cells (LLC-PK(1) cells) were incubated with MTX (0.01 microM, 0.1 microM, and 1 microM), either alone or in combination with 0.1 microM amiloride (Na(+)/H(+) antiporter inhibitor) or 1 microM carbachol (M-cholinergic agonist). Cell viability was then determined by means of trypan blue (TB) exclusion tests and MTT assays. RESULTS: After 4 hr incubation with 0.1 microM MTX the number of viable cells was decreased by 18% in comparison with control cells, and the proportion of dead cells was increased by 38%. Cell death induced by MTX was time-dependent and did not show apoptotic features. On the contrary, cell swelling was discovered. This cell death was prevented by co-incubating the cells with amiloride or carbachol. CONCLUSIONS: MTX induces cell swelling and cell death in renal tubular LLC-PK(1) cells. The tubular cell death induced by MTX is time-dependent. Cell death can be prevented by co-incubating with amiloride, thus indicating that the Na(+)/H(+) antiporter and possibly other volume regulatory factors in renal tubular cells are involved in MTX-induced renal failure.

Amiloride↗
PubMed2006

P-selectin mediates adhesion of leukocytes, platelets, and cancer cells in inflammation, thrombosis, and cancer growth and metastasis.

Stimulated endothelial cells and activated platelets express P-selectin (CD62P), a member of the selectin family of cell adhesion molecules, which interacts with P-selectin glycoprotein ligand-1 (PSGL-1, CD162) for leukocyte rolling on stimulated endothelial cells and heterotypic aggregation of activated platelets onto leukocytes. Cross-linking of PSGL-1 by P-selectin also primes leukocytes intracellularly for cytokine and chemoattractant-induced beta2-integrin activation for firm adhesion of leukocytes. Furthermore, P-selectin mediates heterotypic aggregation of activated platelets to cancer cells and adhesion of cancer cells to stimulated endothelial cells. Here we provide a comprehensive summary of the functional roles and the biological importance of P-selectin-mediated cell adhesive interactions in the pathogeneses of inflammation, thrombosis, and the growth and metastasis of cancers.

Blood Platelets↗
PubMed2006

Specific conductance and ionic characteristics of farm canals in the everglades agricultural area.

Specific conductance in farm canals of the Everglades Agricultural Area (EAA) in south Florida is an important water quality parameter that was categorized as a parameter of concern according to an observed frequency of >5% excursions over the Class III water quality criterion and needed to be addressed as a part of the Everglades Regulatory Program. This study was conducted to evaluate specific conductance in farm canals of the EAA. Specific conductance was monitored at 10 representative farms (a total of 12 pump stations) in the EAA using multi-parameter water quality data loggers, for periods ranging from 24 to 83 mo. Cation and anion concentrations were also determined. Nonparametric Mann-Kendall trend analyses and Sen's slope analysis of specific conductance were conducted to determine specific conductance trends. Mean specific conductance ranged from 0.74 to 1.68 dS m(-1) and only 2 of the 10 farms were above the State Class III water quality criterion of 1.275 dS m(-1). Statistically significant downward trends were observed at 3 of the 10 farms. Determination of ion compositions in grab samples at 8 of the 10 farms indicated that the major ions contributing to the increase in specific conductance in the EAA were Cl-, HCO3-, and Na+. Mean Na/Cl ratios in most of the EAA canals ranged from 0.57 to 0.78, whereas those of SO4/Cl ranged from 0.46 to 0.98. Investigation of historical data and literature indicates that elevated specific conductance in parts of the EAA is a natural phenomenon due to entrapment of connate seawater in the Everglades formation. Sulfur contributes minor increases in specific conductance in the EAA with probable sources from organic soil mineralization, ground water, Lake Okeechobee, and S fertilizers.

Agriculture↗
PubMed2006

Microglial morphology and its transformation after challenge by extracellular ATP in vitro.

The novel morphological characteristics of N9 microglial cells and primary cultured rat microglial cells were examined using the bitotin-IB4 and streptavidin-FITC system. Numerous fine, long processes of both microglial cell preparations formed a network, beginning after 30 min in culture. Dye coupling studies did not show communication between neighbouring cells via the processes in normal conditions. The network of microglial cell processes was well formed into a 'resting state' by 16-24 hr after re-plating. After being challenged by 3 mM ATP the microglial cells were activated, became amoeboid-like cells within 2 hr and finally floated in the culture medium. The complicated network of processes did not retract to the microglial cell body. Flow cytometry analysis showed that the majority of these floating cells were alive and could recover to the resting state after ATP was removed from the culture medium.

Adenosine Triphosphate↗
PubMed2006

A novel heterozygous missense mutation 377T > C (V126A) of TGIF gene in a family segregated with holoprosencephaly and moyamoya disease.

OBJECTIVES: To identify whether any mutations of candidate genes including SHH, ZIC2, SIX3, and TGIF exist in a Taiwanese family segregated with holoprosencephaly (HPE) and moyamoya disease. METHODS: Genotypes of the candidate genes SHH, ZIC2, SIX3, and TGIF were determined in the family members who were available for analysis by sequencing. In addition, genomic regions of another 50 unrelated Taiwanese (100 chromosomes) were studied to verify whether the nucleotide changes we found were mutations or polymorphisms. RESULTS: A novel missense mutation 377T > C and two polymorphisms (420A > G and 487C > T) in the TGIF gene were identified. No mutations in SHH, ZIC2 and SIX3 were found. The mother of the three HPE fetuses was found to be afflicted with moyamoya disease. A brief review of the mutations as well as polymorphisms reported in the TGIF gene up to 2005 is given. CONCLUSION: Molecular diagnosis can help genetic counseling in HPE, which is a heterogeneous disorder with its phenotypic and genotypic spectrum highly widened and variable. The possible association between TGIF mutation and moyamoya disease noted in our study also appeared to be novel.

Adult↗
PubMed2006

Perinatal findings and molecular cytogenetic analyses of de novo interstitial deletion of 9q (9q22.3-->q31.3) associated with Gorlin syndrome.

OBJECTIVES: To present the perinatal findings and the molecular cytogenetic analyses of a de novo interstitial deletion of 9q (9q22.3-->q31.3) associated with Gorlin syndrome. METHODS: Amniocentesis was performed at 18 weeks' gestation on a 27-year-old woman at a community hospital because of a high Down syndrome risk of 1/178, a low maternal serum alpha-fetoprotein (MSAFP) level of 0.66 multiples of the median (MoM), and a high maternal serum human chorionic gonadotrophin (MShCG) level of 3.13 MoM. The karyotype was initially determined to be 46,XY. However, fetal macrocephaly and overgrowth were found at 30 weeks' gestation. Postnatally, the infant manifested characteristic features of Gorlin syndrome. High-resolution chromosomal bandings of the peripheral blood lymphocytes, polymorphic DNA marker analysis to determine the parental origin of the deletion, array comparative genomic hybridization (CGH) to determine the extent of the chromosomal deletion, and fluorescence in situ hybridization (FISH) to determine the deletion of the PTCH gene were performed. RESULTS: The 850-band level of resolution showed an interstitial deletion of 9q (9q22.3-->q31.3). The parental karyotypes were normal. The karyotype of the proband was 46,XY,del(9)(q22.3q31.3)de novo. Polymorphic DNA marker analysis revealed that the deletion was of paternal origin. Array CGH revealed that the deleted region was about 12 Mb, encompassing the segment from 9q22.32 to 9q31.3. FISH analysis using the BAC probe RP11-34D4 and the probe RP11-43505 indicated the deletion of the PTCH gene. CONCLUSIONS: Fetuses with an interstitial deletion of 9q (9q22.3-->q31.3) may be associated with a low level of MSAFP and a high level of MShCG in the second trimester, and sonographic findings of overgrowth and macrocephaly in the third trimester.

Adult↗
PubMed2006

Persistent fifth aortic arch associated with 22q11.2 deletion syndrome.

BACKGROUND: Chromosome 22q11.2 deletion is frequently associated with conotruncal malformations and aortic arch anomalies. This study investigated the association of chromosome 22q11.2 deletion with clinical manifestations in four pediatric patients with persistent fifth aortic arch. METHODS: Four patients with persistent fifth aortic arch treated between July 1997 and June 2004 were included in this retrospective study. There were two girls and two boys, aged 2 days to 11.3 years, with persistent fifth aortic arch and cardiac conotruncal malformations. Chart recordings, plain chest films, two-dimensional and Doppler echocardiograms, cardiac catheterization with angiograms, surgical findings, and cytogenetic study were analyzed. RESULTS: Clinically, all four patients had the cardinal phenotypic features of 22q11.2 deletion syndrome, including cardiovascular malformations (conotruncal malformations and aortic arch anomalies), abnormal facies, thymic hypoplasia, canopy anomaly of the palate (high-arched palate, rather than cleft palate), and hypocalcemia (or hypoparathyroidism). All four patients were confirmed to have chromosome 22q11.2 deletion. CONCLUSION: Congenital conotruncal malformations, including tetralogy of Fallot with pulmonary atresia or stenosis, and aortic arch anomalies including a persistent fifth aortic arch or a right aortic arch, should lead to suspicion of chromosome 22q11.2 deletion when manifested together with any one of the other four cardinal phenotypic features.

Aorta, Thoracic↗
PubMed2006

Interaction between NifL and NifA in the nitrogen-fixing Pseudomonas stutzeri A1501.

Pseudomonas stutzeri strain A1501 isolated from rice fixes nitrogen under microaerobic conditions in the free-living state. This paper describes the properties of nifL and nifA mutants as well as the physical interaction between NifL and NifA proteins. A nifL mutant strain that carried a mutation non-polar on nifA expression retained nitrogenase activity. Complementation with a plasmid containing only nifL led to a decrease in nitrogenase activity in both the wild-type and the nifL mutant, suggesting that NifL acts as an antiactivator of NifA activity. Using the yeast two-hybrid system and purified protein domains of NifA and NifL, an interaction was shown between the C-terminal domain of NifL and the central domain of NifA, suggesting that NifL antiactivator activity is mediated by direct protein interaction with NifA.

Bacterial Proteins↗
PubMed2006

New strategy to prevent ascending cholangitis in larger choledochoduodenal fistula.

BACKGROUND: Choledochoduodenal fistula (CDF) is a complication of common bile duct stones or cholangitis in Asia. It is unclear as to which type of the fistula needs surgical treatment. METHODS: To determine whether the sizes of CDF imply different clinical presentations and treatments, we reviewed 50 patients with CDF and their treatments during a recent 14-year period. For treatments of CDF, we applied the conventional methods, including removal of stone and complete decompression of biliary obstruction to treat the original bile lesions. In addition, according to the sizes of fistula and the frequencies of ascending cholangitis, we proposed the following strategies for fistula treatments: (i) for fistula orifices larger than 1 cm, a transection of common bile duct was applied to prevent the reflux of duodenal juice; (ii) for fistula orifices between 0.5 and 1.0 cm, an effective biliary drainage was applied; and (iii) for fistula orifices less than 0.5 cm, non-surgical treatments were applied. RESULTS: We found that hepatic biliary duct stones and hepatic biliary duct strictures were associated with more severe cholangitis (P = 0.037 and P = 0.009, respectively), but not with the episodes of cholangitis (P = 0.654 and P = 0.664, respectively). In contrast, the sizes of fistula >1 cm were associated with more frequent episodes of cholangitis (r = 0.774; P < 0.001). CONCLUSION: The larger fistula increases frequency of cholangitis episodes and needs surgical treatment for fistula itself.

Bile Duct Diseases↗
PubMed2006

[Detection of proinflammatory cytokine levels in sera from patients with Kaschin-Beck disease].

AIM: To explore the role of proinflammatory cytokines (TNF, IL-1beta and IL-6) in the pathogenesis of Kaschin-Beck disease (KBD). METHODS: The levels of serum TNF, IL-1beta and IL-6 from 62 KBD patients and 60 healthy persons were detected by double antibody sandwich ELISA. RESULTS: The levels of serum IL-1beta and IL-6 in KBD patients were (238.4+/-698.5) ng/L and (164.4+/-661.4) ng/L, respectively, but they were higher than those in healthy persons, being (74.5+/-130.0) ng/L and (52.2+/-154.6) ng/L, respectively. There were no significant differences between them (P>0.05). However, the level of serum TNF in KBD patients [(109.2+/-145.3) ng/L] was significantly higher than that in healthy persons [(40.9+/-89.7) ng/L] (P<0.01). Moreover, there was no correlation between serum TNF and IL-1beta levels (r=0.0387, P>0.05) and TNF and IL-6 in KBD patients (r=0.2135, P>0.05), but there was positive correlation between serum IL-1beta and IL-6 levels (r=0.346, P<0.01). CONCLUSION: The elevated proinflammatory cytokine levels in sera may relate to the pathogenesis of Kaschin-Beck disease.

Adult↗
PubMed2006

[Neuroprotection of chloride channel blockers against NMDA-induced apoptosis of cultured rat hippocampal neurons].

Activation of N-methyl-d-aspartic acid (NMDA) receptor plays an important role in neuronal apoptosis induced by cerebral ischemia but the underlying mechanisms are still unclear. The present study examined the neuroprotection of three chloride blockers in an in vitro cell model of cerebral ischemia established by treatment of cultured rat hippocampal neurons with NMDA. Hoechst 33258 staining and MTT assay were used to detect neuronal apoptosis and cell viability, respectively. The neuroprotective effects of chloride channel blockers on the cell viability and neuronal apoptosis were only observed when the blockers were applied before NMDA exposure. In comparison with DIDS, SITS showed more potent protective effect in a dose-dependent manner, whereas NPPB showed no significant neuroprotective effect. The results demonstrate that pretreatment with both SITS and DIDS have protective effect against neuronal apoptosis, which is achieved by blocking both NMDA receptor and chloride channel.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2006

[Characteristics of free Ca2+ distribution in cultured osteoclast-like cells].

OBJECTIVE: To study the spatial distribution of free Ca2+ in osteoclast-like cells cultured on glass. METHODS: To detect the free Ca2+ in osteoclast-like cells, the images were analyzed with image software, using the laser scanning confocal microscope and fluorescent probe. RESULTS: At 37 degrees C the free Ca2+ in osteoclast-like cells could be labelled effectively with 10 micromol/L Fluo-3/AM, the intensity of Ca2+ fluorescent signal in the central part was greater than that in the peripheral part and in the same section the signal was not distributed evenly. CONCLUSION: The intensity of Ca2+ fluorescent signal is different among various organellae in osteoclast-like cell, which suggests the osteoclast-like cell modulate its own function through the spatial difference of free Ca2+ concentration.

Aniline Compounds↗