Search PubMed⌕ Search

Biomedical subjects

X Yang

Publications and source records attributed to X Yang.

At least 613 records · Page 34Linked to original sources
PubMed1999

[Determination of baicalin and chlorogenic acid in yinhuang granule by capillary electrophoresis].

Yinhuang Granule is a kind of complex formulae made up of extract of Flos lonicerae and that of Radix scutellariae, of the fuctions of dispelling wind-heat to reduce fever, detoxicating, relieving inflammation, promoting urination and tranquilizimg the mind and can be applied to upper respiratory tract infection and tonsillitis. Baicalin and chlorogenic acid are referred to main effective components of it. In this paper, the separation and determination of baicalin and chlorogenic acid in Yinhuang Granule by capillary electrophoresis is described. The experimental conditions are stated as follow: separation column: bare fused-sillica capillary (50 microns i.d., 370 microns o.d., total length 47 cm, 40 cm from the inlet to UV detector); electrolyte: 25 mmol/L borax, pH 8.5; detection wavelength: 310 nm; sampling: 17 kPa.s; running voltage: 25 kV, polarity from anode (inlet) to cathode (outlelt); temperature: 25 degrees C; internal standard: p-nitrobenzoic acid. The linear ranges of determination for baicalin and chlorogenic acid were 160-960 mg/L(r = 0.9993, RSD = 1.76%-2.33%) and 80-960 mg/L(r = 0.9989, RSD = 1.07%-2.51%), respectively. The recoveries of baicalin and chlorogenic acid were (102.09 + 1.74)% (RSD = 1.71%, n = 6) and (99.81 + 3.11)% (RSD = 3.12%, n = 6). The method is simple, fast and accurate. It can be used for the quality control of Yinhuang Granule and its related Chinese medicines.

Anti-Infective Agents↗
PubMed1999

[Chromatographic properties of tetradecylamine bonded stationary phase for reversed-phase liquid chromatography].

A novel bonded stationary phase, tetradecylamine bonded stationary phase (TABP), for reversed-phase HPLC was prepared by bonding 1-tetradecylamine to YWG-80 silica gel through 3-glycidoxypropyltrimethoxysilane. Hydrophobicity, selectivity and silanophilic activity of TABP were evaluated by using aromatic compounds as analytes and methanol-water as binary mobile phase. The orgainc components including acidic, basic and neutral aromatic analytes could be separated satisfactorily with excellent selectivity and peak shape. The relative retention alpha for ethylbenzene-toluene was found to be 1.66 and the asymmetry factors of basic aniline, p-toluidine and N,N-dimethylaniline were found to be 1.26, 1.21 and 1.10, respectively, with the V(methanol):V(water) = 55:45 mobile phase. Aniline was eluted before phenol due to the suppress of the ion exchange activity of residual silanols by the internal masking interaction.

Amines↗
PubMed1999

[Determination of epinephrine, chlorpromazine and promethazine by capillary electrophoresis with scanning voltammetric detector].

With a self-constructed electrochemical detection system, the determination of epinephrine, chlorpromazine and promethazine has been studied by using capillary electrophoresis with scanning voltammetric detector. Scanning potential generation and data acquisition were carried out with D/A and A/D converter board that mounted on a 486DX66 computer. A complex software, which was written by authors in BORLAND C++, was serve to data acquisition, abstraction of three-dimension data, display and print of the electrophorograms. Using a 25 microns x 70 cm fused-silica capillary, the optimum conditions for separation and detection of titled drugs are 10 mmol/L K2HPO4 + H3PO4 (pH 3.0) running electrolyte, 20 kV separation voltage, hydrodynamic injection 10 s at 20 cm height, scanning potential from +0.4 to +1.0 V vs. SCE. With the optimizing condition, the separation of titled drugs is satisfactory, and good reproducibility and low limit are obtained. In this study, all experiments are carried out under air-conditioning (18 degrees C) and constant humidity (relative humidity 50%). In comparison to amperometric detection, scanning voltammetric detection has the advantages of minimizing fouling of the working electrode surface, and direct identification of unknown chemicals by voltammetric curves.

Chlorpromazine↗
PubMed1999

[Separation and determination of the ingredients of cold medicines by capillary electrophoresis with amperometric detection].

Determination and separation of three ingredients--chlorphenamine maleate, acetaminophen and vitamin C in cold medicines by capillary electrophoresis with amperometric detection were carried out. The effects of detection potential and organic modifier were extensively investigated. Separation efficiency could be improved by adding 1, 2-propanediol into buffer. On optimizing condition, chlorphenamine maleate, acetaminophen and vitamin C were separated satisfactorily and eluted within 12 min. The detection limits were 0.02, 0.08 and 0.01 mg/L respectively. The ingredients in several cold medicines were detected successfully. The recoveries of the samples were 94.2%-102.8%. The method is simple, rapid and highly reliable for routine analysis.

Acetaminophen↗
PubMed1999

[Study on proteins of allele by using the microisoelectric focusing].

Clear protein electrophoresis pattern of single pollen grain from Cucurbita pepo L. was obtained with isoelectric focusing and supersensitive stain technique. The results showed that there were two special distributing protein bands near acidity pole. In species I, the two protein bands were a little near to acidity pole and in species II, that was a little far from acidity pole. In species III, the two protein bands distributed either like species I or like species II and the distributed ratio was 1:1. Moreover, we discuss how to identify relative purity of gene with the sorts of the special proteins.

Alleles↗
PubMed1999

[The effect of age on the regional blood flow of neck of femur in normal Chinese].

This study aimed to assess the effect of age on the regional blood flow of neck of femur in normal Chinese. 133Xe washout method was adopted. The result showed that the femur regional blood flow of normal Chinese decreased slowly with the increase of their age. The relation between age and femur blood flow might be expressed as F = -0.042Y + 9.01(F refers to blood flow, Y refers to age). The average femur regional blood flow of normal Chinese was 7.37 +/- 0.62 ml.(100 g.min)-1 for 21-40 years old. The authors suggest this result can be considered to stand for regional femur blood flow of young healthy adults.

Adolescent↗
PubMed1999

[Cloning, sequencing and expression of Sinorhizobium meliloti strain 042B gene nodD].

S. meliloti strain 042B is a rhizobium strain which can form nodules both on alfalfa and on soybean. In this study, nodD gene of 042B was cloned into pBBR1MCS-5. By functional analysis in the system of R. leguminosarum bv. viciae LPR5045 (pSym-, pMP154), it was found that the NodD has responses both to luteolin and to genistein. This result showed that the 042B nodD gene is probably a specific nodulation determinant which determined its capability of nodulation on both alfalfa and soybean. The nodD fragment was then cloned into the expressional vector pThioHis A, B and C, and three recombinant plasmids pXDA, pXDB and pXDC were constructed. The plasmid pXDC was identified to be in the same open reading frame with the trxA gene of pThioHis C throuth sequencing analysis. Inducing IPTG and analyzing with SDS-PAGE, it was found that the fusion protein expressed from E. coli Top10(pXDC) with the molecular weight of TrXA and NodD together. The Western bolt result demonstrated that the expression result is the target gene nodD product.

Amino Acid Sequence↗
PubMed1999

[Effects of combined treatment with flouride and 1,25-dihydroxyvitamin D3 on the histomorphometry and biomechanical properties of bone in ovariectomized rats].

OBJECTIVE: To evaluate the potential use of a combination of bone formation-promoting agents and a differentiation agent of osteoblast as a treatment for postmenopausal osteoporosis. METHODS: The effects of combined and separate administration of flouride-Ca (0.45 ng F- + 13.56 mg Ca2+)/(kg.d) and 1,25-dihydroxyvitamin D (135 pmol/d s.c.) on the histomorphometric parameters in the secondary spongiosa of proximal tibia and biomechanical properties of femoral midshaft in ovariectomized (OVX) rats were examined. RESULTS: Compared with OVX group, OVX + fluoride-Ca group (O + F) and OVX + Fluoride-Ca + 1,25-dihydroxyvitamin D(O + F + D) two kinds of treatment caused 42%, 91% more in %Tb Ar, 14%, 38% more in Tb Wi, 24%, 46% more in Tb N, 26%, 43% less in Tb Sp, 45%, 42% less in % E Pm, 30%, 60% more in Ob Pm respectively. W Wi in O + F treatment had no significant difference from OVX group but 15.2% in O + F + D treatment compared with sham group, MLT increased 16% in O + F group, had no difference from O + F + D. No significant alteration of mechanical strength at femoral midshaft in both O + F and O + F + D was found. There were significant difference in above changes of parameters except % Ob Pm. CONCLUSIONS: Above two treatments could prevent the loss of cancellous bone, reduced the resorption caused by OVX, protected trabecular microarchitecture, and stimulated bone formation significantly. The combined treatment avoided potential mineralization defect caused by F-Ca treatment alone, and two treatments maintained mechanical strength at femoral midshaft.

Animals↗
PubMed1999

[Functional analysis of human A gamma-globin gene promoter with-173 T-->C mutation].

OBJECTIVE: To investigate the effect of the human A gamma-globin gene-173 T-->C mutation on the binding of transacting factors to the promoter and the activity of the promoter. METHODS: Electrophoretic mobility shift assay and transient transfection assay were used in this study. RESULTS: The A gamma-globin gene-173 T-->C mutation decreased the affinity of GATA-1 to the mutant promoter fragment (-201(-)-158) 96% (P < 0.01) and the binding of Oct-1 to the same DNA fragment 55% (P < 0.05). The activity of the mutant promoter was 2-fold (P < 0.05) as strong as that of the normal one in MELGM979 cells. The mutant and the normal promoters exhibited basically same activities in K562 and Hela cells. CONCLUSIONS: The -173 T-->C mutation decreased dramatically the binding of GATA-1, implicating that GA-TA-1 may act as a negative regulator of A gamma-globin gene in adults. The -173 T-->C mutation may enhance the activity of A gamma-globin gene promoter in the adult erythroid cell environment.

Adult↗
PubMed1999

[Overexpression of Bcl-2 inhibited T lymphocyte apoptosis mediated by CD3 epsilon molecule].

OBJECTIVE: To study the role of bcl-2 gene overexpression in T lymphocyte apoptosis mediated by CD8 epsilon chimera molecule. METHODS: The cells expressed CD8 epsilon chimera molecule were transfected with a bcl-2 expression vector. The cells with Bcl-2 overexperssion were selected by G418 and limited dilution, and then treated with anti-CD8 antibody. The cell death was evaluated with flow cytometry. RESULTS: It was shown that there were only 2.6% of cells with Bcl-2 overexpression died by apoptosis. Comparing with Jurkat and TJK cells without Bcl-2 expression, in which there were 6.1% and 33.7% of cell death respectively, suggesting that Bcl-2 overexpression remarkbly inhibited apoptosis of the T lymphocytes mediated by CD8 epsilon chimera molecule. CONCLUSIONS: Bcl-2 overexpression could block T lymphocyte apoptosis mediated by CD3 epsilon molecule and the mechanisms remained to be clarified in detail.

Antibodies, Monoclonal↗
PubMed1999

[Design of blood cell analyzers by using stationary suspending laser light scattering method].

The paper analyses the technology development of automatic blood cell analyzers, put forward the new method of blood cell counting and classification by stationary suspending laser light scattering. The new automatic blood cell analyser is designed by using this method. The design idea of the light route and data acquisition system is stressly provided in the paper. The calibration is performed by using the standard blood cell particulate.

Adult↗
PubMed1999

[The immunological cause of auricular pseudocyst].

OBJECTIVE: To elucidate the relationship between the auricular pseudocyst and the systemic and local immunological status. METHODS: The cyst fluid and blood samples of 44 cases were collected to measure contents of IgG, IgA, IgM and complement C3 by radial immunodiffusion, the content of immune complex by polyethylene glycol turbidimetry, DNA of cytomegalovirus in the fluid by polymerose chain reaction, anti-nuclear antibody(ANA) by immunofluorescent technique and reactions between samples and frozen sections of healthy white rat. RESULTS: Contents of IgG, IgA, IgM and C3 in the cyst fluid were significantly lower than those in the serum (P < 0.01). No immune complex could be detected in both serum and cyst fluid. No DNA of cytomegalovirus was found in cyst fluid, whereas ANA was discovered. Reactive immunocomplex in the auricular cartilaginous tissue was found in the frozen sections of white rats. CONCLUSION: The results suggest that auriular pseudocyst may be an autoimmune disease involving the auricle. The possible mechanism may be an accumulation of reactive exudate due to immunoreactions of autologous antibody and auricular tissue.

Adult↗
PubMed1999

Diagnosis and treatment of the malignant gestational trophoblastic tumor with pulmonary metastasis complicated with pulmonary tuberculosis.

OBJECTIVE: To evaluate the diagnosis and treatment for malignant gestational trophoblastic tumor (MGTT) with pulmonary metastasis complicated with pulmonary tuberculosis. METHODS: To analyze ten cases of MGTT with pulmonary metastasis complicated with pulmonary tuberculosis in our hospital from 1980 to 1997 retrospectively. RESULTS: From the x-ray film, there are great resemblances between MGTT with pulmonary metastasis and pulmonary tuberculosis. Of 10 patients, 7 of them were examined out pulmonary tuberculosis during the chemotherapy of MGTT. Pulmonary tuberculosis appeared six months before chemotherapy in three cases. All of the patients were treated with multiagent chemotherapy. Seven patients achiceved a complete remission, 2 patients developed drug resistance and died of cerebral haemorrhage and cerebral herniation, 1 woman who had achieved a complete remission from MGTT for 14 months died of miliary tuberculosis. CONCLUSION: It is very important to make differential diagnosis of the MGTT with pulmonary metastasis complicated with pulmonary tuberculosis. Trying to avoid excessive anti-tumor treatment owing to mistake pulmonary tuberculosis for pulmonary metastasis, and avoiding missing an opportunity of anti-tuberculosis treatment because of missed diagnosis should be emphasized.

Adult↗
PubMed1999

[A multichannel laser Raman spectral detecting system].

A multichannel laser Raman spectral detecting system is described. It consists of Ar+ laser, outer optics, polychrometer and optical multichannel analyzer (OMA II). Raman spectra of CCl4, C6H6 and C6-H12 were detected. Tests showed that the time required to acquire a Raman spectrum with this/multichannel system is greatly reduced, but the integral time per channel can be expanded to 10-50 s in contrast with a conventional single channel Raman spectrometer. When the working temperature of the multichannel detector is dropped to 5 degrees C, the Raman spectra with high signal to noise ratio, high sensitivity and good quality can be obtained. Processing Raman spectral curves with differential software, the Raman lines which are nearly submerged in Rayleigh line can be picked up.

English Abstract↗
PubMed1999

[A comparison of Fe, Zn, Cu, Cr, Cd and Pb concentration in serum determined by ICP-AES using different sample preparation procedures].

Fe, Zn, Cu, Cr, Cd and Pb concentrations in serum of 21 arteriosclerosis (AS) and 18 healthy control (CK) were determined by ICP-AES, and sample solution was prepared using acid digestion (Dig.) and acid dilution (Dil.) procedure. Serum total Fe, Zn and Cr were significantly higher using Dig. than that using Dil. Serum Cu and Pb were of no significant differences using the both procedures. Serum Cd was significantly lower using Dig. than that using Dil. The results of Fe, Cu, Zn and Cr were positively correlated between Dig. and Dil., but those of Pb and Cd were of no significant correlation. Six elements concentrations in serum determined were significantly different between AS and CK using Dig. The digestion procedure was recommended for serum trace elements analysis using ICP-AES.

Case-Control Studies↗
PubMed1998

Pex18p and Pex21p, a novel pair of related peroxins essential for peroxisomal targeting by the PTS2 pathway.

We have identified ScPex18p and ScPex21p, two novel S. cerevisiae peroxins required for protein targeting via the PTS2 branch of peroxisomal biogenesis. Targeting by this pathway is known to involve the interaction of oligopeptide PTS2 signals with Pex7p, the PTS2 receptor. Pex7p function is conserved between yeasts and humans, with defects in the human protein causing rhizomelic chondrodysplasia punctata (RCDP), a severe, lethal peroxisome biogenesis disorder characterized by aberrant targeting of several PTS2 peroxisomal proteins, but uncertainty remains about the subcellular localization of this receptor. Previously, we have reported that ScPex7p resides predominantly in the peroxisomal matrix, suggesting that it may function as a highly unusual intraorganellar import receptor, and the data presented in this paper identify Pex18p and Pex21p as key components in the targeting of Pex7p to peroxisomes. They each interact specifically with Pex7p both in two-hybrid analyses and in vitro. In cells lacking both Pex18p and Pex21p, Pex7p remains cytosolic and PTS2 targeting is completely abolished. Pex18p and Pex21p are weakly homologous to each other and display partial functional redundancy, indicating that they constitute a two-member peroxin family specifically required for Pex7p and PTS2 targeting.

Acetyl-CoA C-Acetyltransferase↗