Biomedical subjects

Bing Chen

Publications and source records attributed to Bing Chen.

At least 37 records · Page 2Linked to original sources

PubMed2006

The influence of various genotypes on the metabolic activity of NAT2 in a Chinese population.

AIM: To determine the phenotype and genotype of NAT2 in a Chinese population and study the influence of various NAT2 genotypes on the NAT2 activity. METHODS: A reverse dot blot method was used to detect the genotype of NAT2 in 120 healthy Chinese subjects. All subjects were given a single dose of 500 mg sulphadimidine (SM(2)). The plasma concentration of SM(2) and acetyl-SM(2) (AcSM(2)) 6 h after administration was determined. Molar metabolic ratio (MR) was calculated by the ratio of AcSM(2) to AcSM(2)+SM(2). RESULTS: Totals of 53 (44.2%), 47 (39.2%) and 20 (16.7%) subjects were homozygotes for wild type (wt/wt), heterozygotes for mutant (m/wt) and homozygotes for mutant (m/m), respectively. The MR of 120 subjects was 0.714+/-0.237. Twenty subjects (16.7%) were classified as poor metabolizers. All subjects in the m/m group were poor metabolizers. The MRs of the wt/wt, m/wt and m/m groups were 0.886+/-0.060, 0.719+/-0.089 and 0.246+/-0.105 (P<0.001), respectively. There was a significant difference between different NAT2 m/wt genotypes (P<0.001) and m/m genotypes (P<0.001). MR correlated well with NAT2 genotypes (r=0.947). CONCLUSION: Various NAT2 genotypes have a significant impact on the metabolic activity of NAT2 in Chinese people.

Adult↗

PubMed2006

Effects of codon modification on human BMP2 gene expression in tobacco plants.

Bone morphogenetic protein 2 (BMP2) has great potential in therapeutic applications. We are working on generating transgenic plants as a bioreactor to produce BMP2. We have studied the effects of codon optimization on the expression of human BMP2 (hBMP2) in tobacco plants. Three modified hBMP2 genes were transformed into tobacco under the control of either cauliflower mosaic virus 35S (CaMV35S) promoter or double-CaMV35S promoter plus alfalfa mosaic virus (AMV) enhancer. The fused beta-glucuronidase (GUS) reporter gene was used to facilitate the assay of protein expression. The results indicated that codon optimization could increase the protein expression level obviously under CaMV35S promoter. However, under relatively stronger initiation condition (double-CaMV35S promoter plus AMV enhancer), only the gene with the lowest degree of codon optimization could increase the protein expression level. Our findings suggest that the action of codon optimization may be influenced by the factors of promoter strength and A+T content in tobacco plants.

Base Sequence↗

PubMed2006

Neoplastic transformation of human diploid fibroblasts after long-term serum starvation.

Serum starvation for several days has been considered as a positive effect on the efficiency of nuclear transfer using donor cells. The effects of longer period serum starvation are not clear while similar starvation might occur in vitro maintained cells (i.e. tissue engineering products) and in vivo such as ischemia of human tissues or organs. We found human dermis fibroblasts were transformed for about 70 days caused by serum starvation (0.5% serum). The transformed cells became round and had more than one nucleolus. In 0.5% serum medium they kept almost constant growth rate as the normal fibroblasts in 10% serum medium. Abnormal karyotype including aneuploidy and structural aberrations was observed. The transformed cells had high telomerase activities, in contrast, normal fibroblasts had no detectable telomerase activities. C-myc was up-regulated while cdk2, cyclin A, p21 were down in transformed cells. Cell transplantation into SCID nude mice confirmed that the cells had the capacity of forming solid tumors. The results indicated that long-term serum starvation could lead to cell chromosomal instability and transformation.

Animals↗

PubMed2006

[Challenges in management of cerebral ischemia due to Takayasu's arteritis].

OBJECTIVE: To explore the management of cerebral ischemia caused by Takayasu's arteritis. METHODS: One hundred and three cases treated from 1984 to 2003 were reviewed including 92 females. Seven cases underwent ascending aorta to bilateral internal carotid artery (ICA) bypass, 38 cases to the axillary artery with graft to single ICA bypass. Six cases underwent ascending aorta to axillary bypass with 3 graft to single ICA bypasses as the second stage surgery. Three cases underwent ascending aorta to right ICA bypass with 2 graft to left ICA bypasses as well as 6 subclavian to carotid bypass, PTA in 5 and stenting in 3 cases, etc. RESULTS: Twenty-seven patients with less clinical severity received conservative therapy, 9 of them had mostly temporarily improvement, 15 had slight improvement or basically no change, 1 had hemiplegia and 2 died of stroke and myocardial infarction respectively. Surgically, the short-term effective rate was 87% and operative death 7.8%. Fifty-five patients were followed up, a mean follow-up time was 48 months, and the follow-up rate was 80.9%. The excellently, good, fair, no change and death rate were 36.4%, 38.2%, 20.0%, 3.6% and 1.8% respectively. All patients with PTA or stent had an immediate good response and all recurred within 3 to 5 months. CONCLUSIONS: For treating severe cerebral ischemia caused by Takayasu's arteritis, the ascending aorta to axillary and single ICA reconstruction or the ascending aorta-bilateral axillary bypass for patients with subclavian steal syndrome is advocated; second stage operation from graft to contralateral ICA can be carried out if necessary.

Adolescent↗

PubMed2006

The frontal-temporal nerve triangle: a new concept of locating the motor and sensory nerves in upper third of the face rhytidectomy.

BACKGROUND: How to avoid damage to the temporal branch of the facial nerve has long been a central topic of discussion. Recently, damage to the supraorbital nerve, the auriculotemporal nerve, and other branches of the trigeminal nerve divisions has attracted much attention. Focusing on frontal and temporal rhytidectomy, the authors have investigated the course and distribution of the facial nerve branches, the supraorbital nerve, the auriculotemporal nerve, and other branches of trigeminal division. In this article, they present the concept of the frontal-temporal nerve triangle; its contents, vicinity, and clinical significances are discussed. METHODS: An anatomical study was performed using 30 temporal-parietal regions of 10 fixed adult cadavers and five fresh cadavers. A step-by-step dissection from the superficial layer to the deep layer was involved; all the measurement data were analyzed, and the mean and standard deviation were calculated and expressed in centimeters. RESULTS: The frontal-temporal nerve triangle is an approximately triangular area formed by the temporal branch of the facial nerve, the supraorbital nerve, and the auriculotemporal nerve. Together with its contents and vicinal structures, it forms a complicated three-dimensional rather than two-dimensional structure. Anatomical structures closely associated with rhytidectomy are located in or near this area. CONCLUSIONS: Acting as the anatomical body surface landmark for preoperatively locating the temporal branch, the supraorbital nerve, the auriculotemporal nerve, and its related structures, the concept of the frontal-temporal nerve triangle has practical significance in designing incisions and selecting planes of dissection in upper third of the face rhytidectomy.

Facial Nerve↗

PubMed2006

NANOGP8 is a retrogene expressed in cancers.

Nanog is a transcription factor that plays key roles in the self-renewal and maintenance of pluripotency in human embryonic stem (ES) cells. Among Nanog's 11 pseudogenes, NANOGP8 theoretically could be a retrogene, but was considered unlikely as it has not been identified in any expressed sequence tags (ESTs). In this study, we found that NANOGP8 was expressed in several cancer cell lines and in all cancer tissues tested. The complete coding sequence was cloned and the sequence is highly homologous to that of Nanog. We were also able to detect its protein expression using anti-Nanog antibody in recombinant Escherichia coli and some cancer cell lines tested. In addition, expression of NANOGP8 in NIH3T3 cells can promote cell proliferation. The expression of NANOGP8 in cancer cell lines and cancer tissues suggests that NANOGP8 may play important roles in tumorigenesis. This work not only has potential significance in stem cell and cancer research, but it also raises the possibility that some of the human pseudogenes may have regulatory functions.

Animals↗

PubMed2006

Trans-cyclopropanation of mycolic acids on trehalose dimycolate suppresses Mycobacterium tuberculosis -induced inflammation and virulence.

Recent studies have shown that fine structural modifications of Mycobacterium tuberculosis cell envelope lipids mediate host cell immune activation during infection. One such alteration in lipid structure is cis-cyclopropane modification of the mycolic acids on trehalose dimycolate (TDM) mediated by proximal cyclopropane synthase of alpha mycolates (pcaA), a proinflammatory lipid modification during early infection. Here we examine the pathogenetic role and immunomodulatory function of mycolic acid cyclopropane stereochemistry by characterizing an M. tuberculosis cyclopropane-mycolic acid synthase 2 (cmaA2) null mutant (Delta cmaA2) that lacks trans-cyclopropanation of mycolic acids. Although titers of WT and Delta cmaA2 organisms were identical during mouse infection, Delta cmaA2 bacteria were hypervirulent while inducing larger granulomas than WT M. tuberculosis. The hypervirulence of the Delta cmaA2 strain depended on host TNF-alpha and IFN-gamma. Loss of trans-cyclopropanation enhanced M. tuberculosis-induced macrophage inflammatory responses, a phenotype that was transferable with petroleum ether extractable lipids. Finally, purified TDM lacking trans-cyclopropane rings was 5-fold more potent in stimulating macrophages. These results establish cmaA2-dependent trans-cyclopropanation of TDM as a suppressor of M. tuberculosis-induced inflammation and virulence. In addition, cyclopropane stereochemistries on mycolic acids interact directly with host cells to both positively and negatively influence host innate immune activation.

Animals↗

PubMed2006

The molecular cytogenetic aberration analyzed by comparative genomic hybridization and its significance in diffuse large B-cell lymphoma.

OBJECTIVE: To identify genetic alterations in diffuse large B-cell lymphoma (DLBCL) and to analyse the relationship between the genetic aberrations and the clinical characteristics. METHODS: Using comparative genomic hybridization (CGH) to investigate the genomic changes in 24 cases of DLBCL and to analyse the relationship between these aberrations and clinical parameters including Ann arbor stage, systemic symptoms, chemotherapy efficacy and survival. RESULTS: Aberrations were detected in 62.5% patients of 24 cases; the most common chromosomal alterations included loss of 6q15-21 as well as gain of 18q11-ter, of which the incidences were 20.8% and 16.7%, respectively; with comparing clinical parameters between patients with normal CGH and abnormal CGH, we found that patients with abnormal CGH suffered more from stage III-IV and had higher incidence of systemic symptoms, poor chemotherapy efficacy and poor survival (P<0.05), but there was no difference observed in the incidence of extranodal involvement between two groups. CONCLUSION: The gains and/or losses of genomic DNA from DLBCL patients are the common molecular cytogenetic aberrations; loss of 6q15-21 and gain of 18q11-ter are nonrandom event to DLBCL patients; abnormal CGH is a clinical parameter reflecting malignant progressive course and poor survival to DLBCL patients.

Chromosome Aberrations↗

PubMed2006

[Clinical research about the distribution of perineural vascular plexus of the facial nerve].

OBJECTIVE: To objectively evaluate the usefulness and the reliability of the perineural vascular plexus as a landmark for facial nerve as well as whether it will be a landmark for identification of the facial nerve in surgery for otology and neurotology by means of investigating the location of the facial nerve for prevention of iatrogenic facial palsy. METHODS: Prospective case series were designed. Three hundred and eleven consecutive patients were studied which required tympanoplasty for chronic otitis media or microsurgery for facial nerve decompression and congenitally malformation of the ear from July 2002 to July 2005. All the patients were operated by the first author. Perineural vascular plexus as a landmark for identification of the facial nerve in surgery were observed to assess the utility. RESULTS: The well recognized perineural vascular plexus were seen on the horizontal mesotympanic segment of the nerve in 95.8% of patients (298 cases), and only in 4.2% of the patients (13 cases), the vessel plexus was difficult to identify. The 95% confidence interval was from 93.6% to 98.0%. CONCLUSIONS: The vascular plexuses around or over the horizontal portion of the facial nerve provide an early and direct indicator of the location of the facial nerve. The perineural vascular plexus could be a dependable and reliable landmark for the identification the horizontal part of the facial nerve in surgery for otology and neurotology.

Adolescent↗

PubMed2006

[Vocal sound study in supracricoid partial laryngectomy].

OBJECTIVE: Vocal sound was studied in 21 patients underwent supracricoid partial laryngectomy using Dr. Speech. METHOD: Vocal sound tests and frequency spectrum analysis were used in 4 different approaches (CHEP, CHP, TCHEP, TCHP) both before and after the operation. RESULT: Vibration pattern of new glottidis formed after the four different operation approaches was approximately the same demonstrating an augmentation of mucous membrane fluctuation. This vibration pattern were increasing and stabilizing gradually with time. CONCLUSION: Retaining on both sides and one side in supracricoid partial laryngectomy facilitates restoration of vocal function.

Aged↗

PubMed2006

[Preparation of new protein carrier of vaccine against pneumococcal otitis media with genetic engineering technology].

OBJECTIVE: To prepare pneumolysin as a new protein carrier of vaccine against otitis media with genetic engineering technology and establish the base of the study on pneumococcal conjugative vaccines. METHODS: Genomic DNA was isolated from streptococcus pneumoniae. A pair of primers which included two restriction sites was designed based on the published pneumolysin gene sequence. The pneumolysin gene was amplified from pneumococcal DNA with PCR technology. The restriction enzyme digested fragment was linked into the cloning vector PET-28a and the recombinant plasmid DNA containing pneumolysin was then transfected into host cell E. coli JM109 (DE3). RESULTS: DNA fragments were subcloned to construct the complete pneumolysin gene by a conventional coning and PCR. The inserted pneumolysin gene sequence was confirmed by DNA sequencing and the pneumolysin protein was successfully expressed. The relative molecular mass of the expressed product was 52 000. The expressed product amounted to 8% of the total host cell protein. CONCLUSIONS: The pneumolysin gene was successfully cloned into host cell using genetic engineering technology. The recombinant pneumolysin was expressed and purified for preparation. This work laid a foundation of the preparation of pneumococcal conjugative vaccines.

Bacterial Proteins↗

PubMed2006

[The dynamic study of retinoic acid and its alginate sodium microspheres in rabbit eye].

OBJECTIVE: To obtain a intravitreous delay release system by injection of biodegradable polymers (alginate sodium-retinoic acid microspheres, AGS-RA microspheres) to the rabbit vitreous and study the release character of RA delivery system in vitro. METHODS: RA was mixed with 1.5% alginate sodium and microspheres was made by a special electrostatic generator after dissolved in organic solvent; The content of AGS-RA in the microspheres and its release from the microspheres were measured by spectrophotometer. The characteristic of the metabolic dynamics of AGS-RA in the microspheres was analyzed by HPLC. RESULTS: The size of microspheres we manufacture is (95.2443 +/- 8.6265) microm; Medicine contain quantity of RA is (1.7644 +/- 0.0453) microg/mg; Vitro test show that RA in the microspheres is release evenly in the 28 days of observation; Inject medicine to vitreous cavity show no poisonous side effect; The medicine dynamics research of microspheres showed that medicine is being even in 6 weeks releasing [the aqueous RA density of 1, 3 d, 1, 2, 3, 4, 5, 6 weeks is (23.79 +/- 0.15), (33.45 +/- 0.48), (19.95 +/- 0.79), (21.12 +/- 0.47), (19.65 +/- 0.35), (20.01 +/- 0.25), (18.24 +/- 0.27), (18.5 +/- 0.68) ng/ml, respectively]. Just in the 3rd day there is a release summit. CONCLUSION: In vivo and in vitro tests show that AGS-RA microspheres can delay RA release uniformity.

Alginates↗

PubMed2005

Expression of Nanog gene promotes NIH3T3 cell proliferation.

Cells are the functional elements in tissue engineering and regenerative medicine. A large number of cells are usually needed for these purposes. However, there are numbers of limitations for in vitro cell proliferation. Nanog is an important self-renewal determinant in embryonic stem cells. However, it remains unknown whether Nanog will influence the cell cycle and cell proliferation of mature cells. In this study, we expressed Nanog in NIH3T3 cells and showed that expression of Nanog in NIH3T3 promoted cells to enter into S phase and enhanced cell proliferation. This suggests that Nanog gene might function in a similar fashion in mature cells as in ES cells. In addition, it may provide an approach for in vitro cell expansion.

Animals↗

PubMed2005

Distribution of alkylphenols in the Pearl River Delta and adjacent northern South China Sea, China.

The occurrence of alkylphenols (APs) was investigated in surface water and sediments from the Pearl River Delta and adjacent northern South China Sea. Most of the water samples contained detectable amounts of APs, ranging up to 0.628 microg l(-1) for nonylphenol (NP) and 0.068 microg l(-1) for octylphenol (OP). APs were found in all of the sediment samples with concentrations ranging from 59 to 7808 microg kg(-1) for NP and from 1 to 93 microg kg(-1) for OP. The Zhujiang River showed the highest concentrations of APs in both water and sediments. Significant decrease of APs concentrations going from the Zhujiang River to the Shiziyang River was observed. The Xijiang River contained concentrations of APs slightly higher in water but relatively lower in sediments than the Lingding Bay, which might be attributed to their different hydrodynamic and sedimentary characteristics. There was a decreasing trend of APs in water from the rivers to the estuary and further to the sea on the whole. In the Lingding Bay and its outer waters, concentrations of APs in sediments increased to a maximum and then decrease seaward, which was consistent with the distribution trend of the sediment organic carbon contents. Linear regression analyses showed the concentrations of APs were markedly correlated with the sediment organic carbon contents, indicating that the sediment organic carbon is an important factor controlling the levels of APs in sediments.

China↗

PubMed2005

[Primary experimental study on the construction of tissue engineering blood vessel].

OBJECTIVE: To explore the primary experimental methods to construct tissue engineering blood vessel. METHODS: Using the collagen-chitosan to prefabricate the scaffolds with 3-dimensional structure, the proliferated human endothelial cells (ECs), smooth muscle cells (SMCs) and fibroblasts act as the seed cells. The cells were seeded to scaffolds in two-step method, and engineering tissue were matured by static culture or bioreactor culture. Extracellular matrix contents and the platelet aggregation were examined in engineering tissue, tissue engineering blood vessels were taken as patches to repair the man-made defaults on the rats aorta. RESULTS: The proliferated human ECs, SMCs and fibroblast can hold activity and act as seed cells. The prefabricated scaffolds, with excellently cell and tissue biocompatibility, can facilitated cells adherence and upgrowth, the cells quantities and extracellular matrix contents in engineered tissue are time dependent increase (P < 0.05). Platelet aggregation tests confirm the tissue engineering blood vessel have some anti-coagulability. Using the engineering tissue patch to repair the default, 6 aortas in 8 animal were patency till 10 days post-operation. CONCLUSIONS: The seeding cells can be seeded on the 3-dimensional collagen-chitosan scaffolds and matured, the tissue engineering blood vessel can be constructed primarily.

Animals↗

PubMed2005

The influence of NAT2 genotypes on the plasma concentration of isoniazid and acetylisoniazid in Chinese pulmonary tuberculosis patients.

BACKGROUND: Isoniazid (INH) is widely used in the therapy of tuberculosis. Poor metabolizer (PM) of the NAT2 is an important reason of inter-individual difference of the plasma INH concentration. We studied the relationship between NAT2 genotype and INH and its metabolite acetylisoniazid (AcINH) concentration in Chinese people. METHOD: Forty-six tuberculosis patients were enrolled in the study. Each patient took 300 mg INH daily for at least 7 days. Two hours after the INH was given, the vein blood was drawn. NAT2 genotypes of patients were detected by a reverse dot blot (RDB) method. The plasma concentration of INH and AcINH was determined by a precolumn derivation HPLC method. RESULTS: In 46 patients, homozygous mutant (m/m), heterozygous mutant (m/wt) and homozygous wild-type (wt/wt) subjects were 7, 22 and 17, respectively. Plasma concentration of INH and AcINH were 12.74+/-10.51 and 12.49+/-9.61 micromol/l, respectively. There was no statistical difference among 3 genotypes. The ratios of AcINH and INH (R(A/I)) of 3 genotypes were 0.67+/-0.34, 0.88+/-0.40 and 1.69+/-0.66, respectively. The R(A/I) of m/m and m/wt group were significantly lower than wt/wt group (P<0.01). CONCLUSION: The results suggest that various NAT2 genotypes in Chinese tuberculosis patients have great impact on the metabolism capacity of NAT2. This finding maybe valuable in the rational use of relevant drugs.

Antitubercular Agents↗

PubMed2005

1-(2-Methyl-5-phenyl-3-thienyl)-2-(3-methyl-5-phenyl-2-thienyl)-3,3,4,4,5,5-hexafluorocyclopent-1-ene: a novel photochromic hybrid diarylethene.

The title compound, C27H18F6S2, a novel photochromic hybrid diarylethene derivative containing 2- and 3-thienyl substituents, is one of the most promising photochromic candidates with shorter wavelength for optical storage and other optoelectronic devices. In the crystal structure, the molecule adopts a photoactive antiparallel conformation. The distance between the two reactive C atoms, i.e. the ring C atoms to which the methyl groups are attached, is 3.430 (4) A. The dihedral angles between the thienyl and adjacent phenyl rings are 26.8 (2) and 33.98 (9) degrees.

Journal Article↗

PubMed2005

Can greenhouses eliminate the development of cold resistance of the leafminers?

Latitudinal patterns for quantitative traits in insect are commonly used to investigate climatic adaptation. We compare the cold resistance of the leafminer (Liriomyza sativae) pupa among populations distributed from tropical to temperate regions, incorporating the thermal overwintering limit of the insect's range. The patterns of cold resistance for northern and southern populations differ. The southern populations significantly increased their cold resistance with latitude, showing a latitudinal pattern independent of seasons, acclimation regimes, and assay methods. In contrast, the northern populations showed no stable patterns; they were always intermediate in cold hardiness between the low-latitude and high-latitude populations within the overwintering limit. Integration of these data with those of the biologically similar congeneric leafminer, L. huidobrensis, suggests that a pattern shift in stress tolerance associated with the overwintering range limit is probably a general adaptive strategy adopted by freeze-intolerant species that have a high-latitude boundary of distribution, but can only overwinter and develop in protected greenhouses in harsh seasons. Considering the widespread availability of greenhouses for overwintering insects in northern China, we speculated that the large-scale existence of thermally-buffered microhabitats in greenhouses might eliminate the development of cold resistance of the leafminer populations. However, results suggest a strong selection for increased cold resistance for natural populations of Liriomyza species at higher latitudes that can overwinter in the field, but not for populations at latitudes above the thermal limit. Thus, habitat modification associated with greenhouses can limit gene flow and reduce cold tolerances even at latitudes above where the leafminers can overwinter in the field.

Adaptation, Biological↗