Biomedical subjects

B Chen

Publications and source records attributed to B Chen.

At least 127 records · Page 7Linked to original sources

PubMed2001

[The effects of DiBaiRen decoction on the proliferation of human keratinocytes and its in vitro anti--oxidation role].

OBJECTIVE: To investigate the effects of DiBaiRen decoction on the proliferation of human keratinocytes and its in vitro anti -- oxidation role. METHODS: Human keratinocytes were cultured in vitro in the media containing gradient diluted DiBaiRen decoction. The cell proliferation rates at different culture times were recorded. Cellular oxidation injury inflicted by superoxide anion and hydroxyl anion was produced by adding hypoxanthine -- xanthine oxidase and hydrogen peroxide to the culture media. MTT colorimetry was employed to determine cellular activity. The antagonistic effects of DiBaiRen decoction on cellular oxidation injury were analyzed. RESULTS: In the case that DiBaiRen decoction was added to the culture in concentrations of 30 ml/L to 100 ml/L, there exhibited obvious accelerated proliferation of the keratinocytes, with evident shortening of the cell fusion time. In addition, the oxidation injury of cultured keratinocytes caused by hypoxanthine -- xanthine oxidase and hydrogen peroxide was ameliorated or eliminated by the addition of DiBaiRen decoction, and the effects were dose -- dependent. CONCLUSION: DiBaiRen decoction might possess anti -- oxidation effects and could promote the in vitro proliferation of cultured human keratinocytes, and it might be beneficial in wound protection and epithelization.

Antioxidants↗

PubMed2001

[SFE-CGC determination of tanshinone in Salvia miltiorrhiza Bunge].

AIM: To analyze tanshinone IIA in Salvia miltiorrhiza Bunge by supercritical fluid extraction (SFE) coupled with capillary gas chromatography (CGC). METHODS: The solution pressure was predicted by solubility parameter theory, the extraction conditions were confirmed by orthogonal design in which temperature, volume of modifier and dynamic extracting volume had been studied in three levels. RESULTS: This method is quick, convenient, precise and accurate, added sample recovery is 95.3%, RSD = 4.27%. CONCLUSION: Compared with the method of ultrasonic extraction, significantly better qualitative and quantitative result could be obtained by SFE-CGC and expend less organic solvent then make less pollution.

Abietanes↗

PubMed2001

[Allele specific amplification for CYP2D6 gene related to intermediate metabolizer in Chinese subjects].

AIM: To establish an allele specific PCR amplification (ASA-PCR) for determination of the genotype of CYP2D6* 10B polymorphism in Chinese subjects. METHODS: CYP2D6* 10B alleles of 65 healthy Chinese subjects were analyzed by a two-step PCR assay and the correlation of genotype and phenotype was studied. RESULTS: There were 20 CYP2D6* 10B heterozygous genotypes subjects (wt/m) in 35 very extensive metabolizers (VEMs), which consisted the major part of VEM subjects (57%). Meanwhile, 20 subjects consisting 69% of 29 intermediate metabolizers were CYP2D6* 10B homozygous mutant genotypes (m/m). The poor metabolizer was also m/m. The metabolic ratio of CYP2D6* 10B m/m subjects were larger than wt/m and wild type, the values were -1.49 +/- 0.54, -2.20 +/- 0.49 and -2.47 +/- 0.61 (P < 0.01). CONCLUSION: PCR-ASA was shown to be a rapid and specific method. It can be used to study the genetic polymorphism, especially CYP2D6 intermediate metabolism.

Adult↗

PubMed2001

[Relative bioavailability of effervescent tablet of potassium chloride in healthy volunteers].

AIM: To probe the approach by which the pharmacokinetics and relative bioavailability of endogenous medicinal substances can be studied. METHODS: A randomized three-crossover study was performed in 18 healthy male volunteers. In two of the three study periods, a single 2 g dose of either effervescent tablet or common tablet of potassium chloride was administered; whereas in one of three periods no drug treatment was given to allow the nondrug-related (endogenous) potassium in urine to be determined. In each period the urine samples were collected at the following intervals: 0-2, 2-4, 4-6, 6-8, 8-10, 10-12, 12-24, 24-48 h after dose. Urine potassium was determined and the cumulative urine potassium-time data were fitted to a one-compartment model with first-order absorption. Bioavailability was represented by cumulative amount of potassium excreted in urine during 48 hours after drug administration and the bioequivalence of the two formulations was evaluated by analysis of variance and two one-sided t-test. RESULTS: The pharmacokinetic parameters were as follows: effervescent tablet T1/2 ke = (6 +/- 5) h, T1/2 ka = (0.08 +/- 0.08) h, ku = (0.09 +/- 0.04) h-1, Xmax/f = (18 +/- 8) mmol; common tablet T1/2 ke = (8 +/- 5) h, T1/2 ka = (0.11 +/- 0.11) h, ku = (0.07 +/- 0.04) h-1, Xmax/f = (18 +/- 8) mmol. Relative bioavailability of effervescent tablet was 97.5% +/- 15.2% compared with common tablet. CONCLUSION: The two formulations were of bioequivalence. The methods used in this study might be applicable to other similar studies involving endogenous medicinal substances.

Adult↗

PubMed2001

[Surgical sutures and their clinical applications].

This article describes the development of surgical sutures and their clinical spplications. It is classified as absorbable and non-absorbable sutures. Besides it discusses the suture's tension strength and tissue reaction, points out the advantages and the shortcomings.

Absorption↗

PubMed2001

The tree shrew apolipoprotein C-I cDNA: sequence and its expression.

A rabbit anti-serum to tree shrew apolipoprotein C-I (apo C-I) was used to screen an expression cDNA library constructed by us from tree shrew (TS) liver tissue. Two apo C-I cDNA clones were obtained. The longer one consists of 380 nucleotides, including 21 bp and 95 bp at the 5' and 3' end of the non-translated regions respectively, and a 264-bp fragment in an open reading frame encoding 88 amino acids prepropeptide which contains 26 amino acids of signal peptide and a mature protein (62 amino acids). Comparing the amino-acid sequence deduced from this cDNA with those of the published mammalian apo C-Is reveals that it shared some structural similarity with rat, mouse and dog apo C-I, but it had 5 more amino acids than that of human and baboon. The expression of apo C-I mRNA in 8 different tissues were also assayed with Northern blot. The results demonstrated that liver had the highest expression, intestine had much less expression and no expression in other tissues, which is much different from human and other species. This study has laid down a good foundation for further studying on the function and the stucture of tree shrew apo C-I gene.

Amino Acid Sequence↗

PubMed2001

[Monte Carlo simulation of FCS in a laser gradient field].

Fluorescence correlation spectroscopy (FCS) is a powerful tool for probing biological process inside living cells. It measures fluorescence fluctuations of small number of molecules and derive information on molecular kinetics and reactions. We have developed a Monte Carlo model to simulate Browning motion of Rayleigh particles in a laser gradient field. The simulation reveals relations between laser field strength and measured parameters from FCS, such as diffusion coefficient and number density of the particles. The simulated results agree qualitatively to the experimental results obtained using fluorescent spheres. Empirical relations from the simulation are also discussed.

Computer Simulation↗

PubMed2001

[A study on the concentration quenching of Tm3+ upconversion luminescence].

In this work, we have a designation and preparation of MFT glasses for upconversion, the glasses consisted of TeO2 and fluoride: PbF2, AlF3, BaF2, NaF and the impurity Tm2O3. In this glass system the oxide improve forming ability, the fluorides improve the microscopic environment around RE ions in glasses. In this glass host the content of Tm2O3 achieves to 4% mol and crystallization no occurred. A detail study on the concentration quenching of upconversion luminescence for 1G4-->3H6 and 1D2-->3H4 transitions was completed. The experimental results directed that the quenching concentration was 0.6 mol.% and higher 3 times than in other glasses materials. The cross relaxation and mechanism of concentration quenching were discussed.

Attention↗

PubMed2001

[In situ IR study of the reaction behavior of clusters [VnCr3-n (mu 3-O) (mu-O2CCH3)6(THF)3]X[n = 0-3, X = Cl-, ClO4-, (VO5)0.5-] and [VnFe3-n(mu 3-O) (mu-O2CCH3)6(THF)3]X(n = 0-3, X = Cl-) in nitrogen atmosphere].

The reaction behavior of the title complexes have been investigated by means of in situ IR in nitrogen atmosphere. It has been found that they enabled the acetic acid to convert to acetone and methane in different temperatures. The results indicate that the sequence of the ketonization reaction activity for the clusters was [V3OAT] > [VFe2OAT], [V2CrOAT] > [Fe3OAT], [VCr2OAT] > [Cr3OAT] [OAT = (mu 3-O) (mu-O2CCH3)6 (THF)3], and the sequence of the methanation reaction activity for the clusters was [Cr3OAT] > [VCr2OAT], [V2CrOAT] > [V3OAT] > [VFe2OAT], [Fe2OAH]. The ketonization reaction activity of [Fe3OAT] were obviously lower than that of [Fe3OAH] [OAH = (mu 3-O) (mu-O2CCH3)6 (H2O)3] and the methanation reaction activity of [Cr3OAT] were also much lower than that of [Cr3OAH]. The difference between [Fe3OAH], [Cr3OAT] and [Fe3OAH], [Cr3OAH] mentioned above were discussed.

English Abstract↗

PubMed2001

[In situ IR study of the reaction behavior of transition metal oxides-propionic acid system, Fe2Cr(mu 3-O) (mu-O2CC2H5)6(H2O)3Cl.xH2O and Cr3 (mu 3-O) (mu-O2CC2H5)6(H2O)3NO3.xH2O].

The reaction behavior of the title complexes have been investigated by means of in situ IR in nitrogen atmosphere. It has been found that they enabled the propionic acid to convert to acetaldehyde and pentanone in different temperature. The sequence of the ketonization reaction activity for metal oxides Fe3O4 > MnO2 > Cr2O3 > Co2O3 > Ni2O3 has analogy to that for metal clusters [Fe2MnOPH] > [Fe3OPH] > [Fe2CrOPH] > [Fe2CoOPH] > [Fe2NiOPH] > [Cr3OPH][OPH = (mu 3-O)(mu-O2CC2H5)6(H2O)3]. For the ketonization reactions, the reaction temperatures of transition-metal oxides were much higher than that of corresponding metal clusters [Fe2MOPH]. It has been verified that the active component of metal cluster [Fe2MOPH] is not the corresponding transition-metal oxides. The difference between Fe3O4 and Fe2O3 which catalyze the conversion of propionic acid to acetaldehyde and pentanone respectively were demonstrated.

English Abstract↗

PubMed2001

[Endovascular treatment for peripheral arterial stenosis with endoluminal stent].

OBJECTIVE: To initially evaluate the effect and security of endovascular treatment for arterial stenosis with endoluminal stent. METHODS: Thirty-four cases of arterial stenosis were treated with endoluminal stent from March 1999 to May 2001. The stenosis involved descending aorta (1 case), iliac artery (2), femoral artery (2), carotid artery (1), subclavian artery (2) and renal artery (1). Thiry-three cases had arteriosclerosis and one Takayasu's arteritis. Twenty-six cases were percutaneously punctured and eight cases were punctured directly. RESULTS: All the 34 cases had the stents successfully implanted. However, one case of descending aorta stenosis died on the operation day due to rupture of the descending aorta. Dissection was performed in thirteen cases after balloon dilation and hematoma was seen at the puncturing point in eleven cases. TIA (transient ischemia attack) and cerebral infarction did not occur in the case of carotid arterial stenosis. For those with stenosis in lower extremities, ABI (ankle-brachial index) increased from 0.45 to 0.72 postoperatively. The brachial pressure of two cases of subclavian arterial stenosis returned to normal postoperatively. The blood pressure of case of renal arterial stenosis reduced from 180/120 mm Hg to 140/90 mm Hg. All the cases were followed up for one month to 26 months. Thrombosis of the arteries treated occurred in two cases of iliac arterial stenosis four and six months postoperatively. CONCLUSIONS: The effect of endovascular treatment for arterial stenosis with endoluminal stent is satisfactory. Endovascular therapy is especially suitable for iliac arterial and limited stenosis of the subclavian artery. However, it should be cautiously used in the stenosis of the carotid artery.

Adult↗

PubMed2000

The effect of surface coatings on the association of orthophosphate with natural colloids.

A new method has been utilised for the characterisation of natural particle surface coatings. The method involves the use of sedimentation field-flow fractionation (SdFFF), radiolabelling and inductively coupled plasma-high resolution mass spectrometry (ICP-HR MS) techniques to study the effect of colloidal surface coatings on the adsorptive behaviour of orthophosphate. Colloidal river sediment and soil samples were chemically treated in an attempt to selectively remove metal hydroxyoxides and natural organic matter. The samples were then radiolabelled with 33PO4(3-) and analysed by SdFFF to determine the surface adsorption density (SAD) of orthophosphate as a function of particle size. The SdFFF unit was directly coupled to an ICP-HR MS to determine the chemical composition of the colloidal samples as a function of particle size. Element concentration/UV detector signal and element atomic molar ratios were plotted against particle size, and the trends used in the interpretation of SAD distribution (SADD) changes for the samples were studied. In general, non-constant trends in the orthophosphate SADDs were found, except for the river sediment treated with hydroxylamine hydrochloride. The results indicated that, in the soil sample studied, the Mn oxide coating was a dominant factor in determining phosphorus adsorption. This method could also be applicable to other industrial or similar samples.

Adsorption↗

PubMed2000

Increased hippocampal supragranular Timm staining in subjects with bipolar disorder.

Biochemical and structural abnormalities have been reported in hippocampus of subjects with mood disorders. This study examined the organization of mossy fibers in anterior hippocampus of subjects obtained from the Stanley Neuropathology Consortium. Frozen postmortem hippocampal sections from subjects with major depression, bipolar disorder, schizophrenia and non-psychiatric controls were stained using the Neo-Timm procedure, which selectively stains mossy fibers. Increased Timm staining in the supragranular layer was found in subjects with bipolar disorder relative to control subjects. These results are suggestive of neuronal sprouting in hippocampus of subjects with bipolar disorder. There were no significant associations between supragranular Timm staining and suicide, length illness or drug treatment at the time of death.

Adult↗

PubMed2000

Expression, purification, and characterization of gp160e, the soluble, trimeric ectodomain of the simian immunodeficiency virus envelope glycoprotein, gp160.

The envelope glycoprotein, gp160, of simian immunodeficiency virus (SIV) shares approximately 25% sequence identity with gp160 from the human immunodeficiency virus, type I, indicating a close structural similarity. As a result of binding to cell surface CD4 and co-receptor (e.g. CCR5 and CXCR4), both SIV and human immunodeficiency virus gp160 mediate viral entry by membrane fusion. We report here the characterization of gp160e, the soluble ectodomain of SIV gp160. The ectodomain has been expressed in both insect cells and Chinese hamster ovary (CHO)-Lec3.2.8.1 cells, deficient in enzymes necessary for synthesizing complex oligosaccharides. Both the primary and a secondary proteolytic cleavage sites between the gp120 and gp41 subunits of gp160 were mutated to prevent cleavage and shedding of gp120. The purified, soluble glycoprotein is shown to be trimeric by chemical cross-linking, gel filtration chromatography, and analytical ultracentrifugation. It forms soluble, tight complexes with soluble CD4 and a number of Fab fragments from neutralizing monoclonal antibodies. Soluble complexes were also produced of enzymatically deglycosylated gp160e and of gp160e variants with deletions in the variable segments.

Animals↗

PubMed2000

Chronic valproate treatment increases expression of endoplasmic reticulum stress proteins in the rat cerebral cortex and hippocampus.

BACKGROUND: Sodium valproate is a highly effective treatment for bipolar disorder, but its mechanism of action remains poorly understood. We recently found with differential display polymerase chain reaction that valproate regulates the expression of the endoplasmic reticulum stress protein GRP78 in the rat cerebral cortex. In our study, we investigated the effect of this drug on the other members of the endoplasmic reticulum stress protein family, GRP94 and calreticulin, and we studied the brain regional distribution of GRP78, GRP94, and calreticulin. METHODS: Immunohistochemistry was used to measure protein levels of GRP78, GRP94, and calreticulin after treatment with sodium valproate (300 mg/kg, intraperitoneal) in specific rat brain regions. RESULTS: We report here that chronic treatment with valproate also increased expression of other members of the endoplasmic reticulum stress protein family, such as GRP94 and calreticulin. The brain regional distribution of these changes was similar for all three proteins, with marked increase detected in the frontal cortex, parietal cortex, and CA1 region of the hippocampus. CONCLUSIONS: Because GRP78, GRP94, and calreticulin possess molecular chaperone activity and bind Ca(2+) in the endoplasmic reticulum, the pharmacologic action of valproate may involve one or more of these processes.

Animals↗

PubMed2000

Chemical grafting of molecularly imprinted homopolymers to the surface of microplates. Application of artificial adrenergic receptor in enzyme-linked assay for beta-agonists determination.

A technique for coating of microplate wells with a molecularly imprinted polymer (MIP), specific for epinephrine, is presented. 3-Aminophenylboronic acid was polymerized in the presence of epinephrine using oxidation of the monomer by ammonium persulfate. This process resulted in the grafting of a thin polymer layer onto the polystyrene surface of the microplates. The polymer affinity was determined by an enzyme-linked assay using a conjugate of horseradish peroxidase and norepinephrine (HRP-N). It was found that imprinting resulted in increased affinity of the polymer toward HRP-N and epinephrine. Influence of the buffer pH and concentration on the polymer affinity was analyzed. It was shown that the MIP-coated microplates could be used for assay development and drug screening. The high stability of the polymers and good reproducibility of the measurements make MIP coating an attractive alternative to traditional antibodies or receptors, used in ELISA.

Adrenergic beta-Agonists↗

PubMed2000

Persistence of Mycobacterium tuberculosis in macrophages and mice requires the glyoxylate shunt enzyme isocitrate lyase.

Mycobacterium tuberculosis claims more human lives each year than any other bacterial pathogen. Infection is maintained in spite of acquired immunity and resists eradication by antimicrobials. Despite an urgent need for new therapies targeting persistent bacteria, our knowledge of bacterial metabolism throughout the course of infection remains rudimentary. Here we report that persistence of M. tuberculosis in mice is facilitated by isocitrate lyase (ICL), an enzyme essential for the metabolism of fatty acids. Disruption of the icl gene attenuated bacterial persistence and virulence in immune-competent mice without affecting bacterial growth during the acute phase of infection. A link between the requirement for ICL and the immune status of the host was established by the restored virulence of delta icl bacteria in interferon-gamma knockout mice. This link was apparent at the level of the infected macrophage: Activation of infected macrophages increased expression of ICL, and the delta icl mutant was markedly attenuated for survival in activated but not resting macrophages. These data suggest that the metabolism of M. tuberculosis in vivo is profoundly influenced by the host response to infection, an observation with important implications for the treatment of chronic tuberculosis.

Animals↗

PubMed2000

The glioma-associated protein SETA interacts with AIP1/Alix and ALG-2 and modulates apoptosis in astrocytes.

Expression of the src homology 3 (SH3) domain-containing expressed in tumorigenic astrocytes (SETA) gene is associated with the tumorigenic state in astrocytes. SETA encodes a variety of adapter proteins containing either one or two SH3 domains, as suggested by the sequence heterogeneity of isolated cDNAs. Using both SH3 domains in a yeast two-hybrid screen of a glial progenitor cell cDNA library, we isolated the rat homolog of the ALG-2-interacting protein 1 or ALG-2-interacting protein X (AIP1/Alix). In vitro confrontation experiments showed that the SH3-N domain of SETA interacted with the proline-rich C terminus of AIP1. In co-immunoprecipitation experiments, SETA and AIP1 interacted and could form a complex with apoptosis-linked gene 2 protein. Endogenous SETA and AIP1 proteins showed similar patterns of staining in primary rat astrocytes. Misexpression of a variety of SETA protein isoforms in these astrocytes revealed that they localized to the actin cytoskeleton. Furthermore, SETA proteins containing the SH3-N domain were able to sensitize astrocytes to apoptosis induced by UV irradiation. Expression of the isolated SH3-N domain had the greatest effect in these experiments, indicating that interference in the interaction between endogenous SETA and AIP1 sensitizes astrocytes to apoptosis in response to DNA damage.

Actins↗