Biomedical subjects

L Yang

Publications and source records attributed to L Yang.

At least 163 records · Page 9Linked to original sources

PubMed2001

[High level secretion expression of porcine somatoropin gene in Pichia pastoris and N-glycosylation analysis of products].

The porcine somatoropin gene was inserted into the Pichia pastoris expression vector of pPICZ alpha A which contains AOX I promoter and alpha-factor signal sequence. The recombinant plasmid of pPICZ alpha A-pST was linearnized by Sac I and transformed into X-33 by electroporation. The multi-copy insert transformants were selected and cultivated in flasks. SDS-PAGE and Western blot analysis showed that PST gene products were observed in the supernants with a little larger molecular weight size than the natural PST's, however, the molecular weight size of the PST gene products in the soluble cellular proteins were identical to the natural PST's. Retransformation of the linearnized pPICZ alpha-pST showed the expression level was improved greatly and rPST has the same antigenicity as natural one. The expressed rPST accumulated up to about 956 mg/L. The N-glycosylation analysis showed rPST had no N-glycosylation.

Animals↗

PubMed2001

[Study on active constituents of traditional Chinese medicine reversing multidrug resistance of tumor cells in vitro].

OBJECTIVE: To screen drugs reversing multidrug resistance of tumor cells from active constituents of traditional Chinese medicine and to study the reversal action. METHODS: The kill effects of the drugs on tumor cell lines in vitro were determined with MTT method. The Jin's formula was used to analyse the effect of drug combination. RESULTS: 5 micrograms/ml rhynchophylline, 2 micrograms/ml jatrorrhizine and 1.25 micrograms/ml indirulin could reverse multidrug resistance for vincristine on KBv200 cell line by 16.8, 5.1 and 4 fold respectively. 1.56-12.5 micrograms/ml curcumine combining with vincristine could sensitize antitumor effect both on KB and KBv200 cell lines. CONCLUSION: All rhynchophylline, jatrorrhizine and indirulin could reverse multidrug resistance for vincristine on KBv200 cell line. Curcumine combinating vincristine could sensitize antitumor effect both on kB and kBv200 cell lines.

Antineoplastic Agents, Phytogenic↗

PubMed2001

[Study on the quality standards for xianghe suppository].

The quality standards for Xianghe suppository were studied. The TLC methods for identification of Rhizoma Coptidis, Radix Sophorae Flavescentis and Flos Caryophylli were established. A simple high performance liquid chromatographic method was established for determination of berberine and palmatine. The mobile phase was acetonitrile-water(1:1, containing KH2PO4 3.4 g, CH3(CH2)11 SO4Na 1.7 g per 1000 ml). UV detecting wavelength was 345 nm. This method is suitable for the quality control of Xianghe suppository.

Berberine↗

PubMed2001

[Influence of transfection of sense- and antisense-cyclin A gene on human squamous cell carcinoma of tongue].

OBJECTIVE: To investigate the effect of human sense- and antisense-cyclin A gene on human squamous cell carcinoma of tongue cell line (Tca 8113). METHODS: Tca8113 cells were transfected with an expression vector containing a full length human sense-cyclin A or antisense-cyclin A gene by gene transfer with DNA-liposome. A series of methods, such as the changes of cell proliferation, DNA-flow cytometric analysis, silver binding nucleolar organizer regions (AgNORs) and expressions of cyclin A and Ki-67 were studied on transfected cell and untransfected cell. RESULTS: The cells transfected by antisense-cyclin A gene showed growth inhibition in vitro and decreased proliferation. The proliferation index(PI) was reduced (0.231 vs 0.421) as compared with untransfected cell group, and FCM analysis showed that Tca8113 cells transfected with antisense-cyclin A were arrested at G0/1 phase. The mechanism of such changes described might be associated with the lower expression of cyclin A mRNA in antisense-cyclin A gene transfected cells. However, opposing changes were observed in the sense-cyclin A gene transfected cells. CONCLUSIONS: Antisense cyclin A could inhibit target gene expression and partly reverse malignant phenotype of squamous cell carcinoma of tongue.

Carcinoma, Squamous Cell↗

PubMed2001

Sesquiterpene polyol esters from Euonymus phellomana Loes.

Three new (1-3) and six known (4-9) beta-dihydroagarofuran sesquiterpene polyol esters were isolated from a methanol extract of the seed oil of Euonymus phellomana Loes. and their structures were established on the basis of spectral analysis, including 2D-NMR spectroscopy.

China↗

PubMed2001

Changes of blood circulation of the extremity after external fixation for tibia shaft defect: an experimental study.

OBJECTIVE: To assess and compare two approaches, end to end compression with lengthening (EECL) and segmental bone transport by lengthening (STBL), for long tubular bone defect and nonunion. METHODS: Ten goats were used to establish the bone defect model of the mid-tibia. The bone defect ends were shortened step by step with a sulcated half-ring external fixator. Changes of the blood flow of the distal extremity were measured with pulse-Doppler monitor and angiography. RESULTS: The blood flow in the distal extremity was not affected when bone defect was less than 15% of the original length. Blood circulatory disorder would appear in the distal extremity when bone defect ranged 15%-20% of the original length. The necrosis would appear in the extremity because of the blood circulatory obstacle when bone defect was more than 20% of the original length. CONCLUSIONS: EECL is an appropriate alternative of treatments if bone defect is less than 15%; while SBTL may be feasible if bone defect is over 20% of the original length. When bone defect ranges between 15% and 20%, EECL should be applied with great care on condition of keeping watch on the extremity circulation with pulse-Doppler monitor.

Angiography↗

PubMed2001

[A simplified and quantitative method for culturing and isolating Legionella from air condition cooling waters].

OBJECTIVE: To establish simplified technique to investigate the distribution of Legionella from air condition cooling waters in a district in Shanghai. METHODS: Using simplified method to make GVPC agar plates; using candle jar to replace CO(2) incubator; initial identification was only relied on colony appearance but no growth on the blood agar plate; and a simple formula was used to quantify the Legionella in waters. RESULTS: From July 1997 to June 1999 in Luwan District Shanghai, the simplified methods were used to culture and isolate 185 Legionella strains from 371 water samples (47 fixed spots of hotels, markets, resident buildings, hospitals, subway stations, cinemas and stadiums), with a detection rate of 49.87% with highest at the subway stations (69.36%), which were significantly higher than repeated in the literature in this country and abroad. CONCLUSIONS: Simplified methods were established for culturing, isolating and quantifying Legionella. These methods had been used for 3 years to have got a high Legionella detection rate from the cooling waters. The high detection rate and quantity of Legionella in cooling waters of subway stations call for more attention to the fact that Legionellosis might exist in these waters.

Air Conditioning↗

PubMed2001

[Overexpression of bcl-2 protects HCC-9204 hepatoma cells from ethanol-induced apoptosis].

OBJECTIVE: To explore the effect of apoptosis-associated gene bcl-2 overexpression on ethanol-induced apoptosis in hepatocellular carcinoma (HCC) cells. METHODS: The plasmid of retrovirus expression vector pDOR-SB, which contains human bcl-2 cDNA, was transfected into a HCC cell line HCC-9204 cells whose bcl-2 protein expression is below detectable level. The expression of bcl-2 protein was detected by immunohistochemical ABC method. The cells were cloned continually until a monoclonal cell strain which expressed bcl-2 protein at a 100% positive rate was obtained, and the cells were detected with flow cytometry. After the above cells were treated with 6% ethanol for 6 h, the happening of apoptosis were detected by MTT assay, TUNEL assay and flow cytometry. RESULTS: bcl-2 protein expression was detected in most of the cells which had been transfected with pDOR-SB, while it was bcl-2 protein negative in cells transfected with pDOR empty vector or non-transfected HCC-9204 cells. The obtained monoclonal cell strain expressed bcl-2 protein at a 100% positive rate under flow cytometer after being cloned 3 times in succession, and was named HCC-bcl-2. After being treated with 6% ethanol, the optical absorbance data of HCC-bcl-2 cells and non-transfected HCC-9204 cells detected by MTT assay were 0.519 +/- 0.053 and 0.366 +/- 0.046, respectively, the former was significantly higher than the latter (P < 0.01). Their TUNEL index was 0.387 and 0.613 respectively, and their sub-G1 apoptotic peak scale was 3.8% and 10.7% respectively, the former were all lower than the latter (P < 0.05). CONCLUSION: Overexpression of bcl-2 protein can suppress ethanol-induced apoptosis in HCC-9204 hepatoma cells.

Apoptosis↗

PubMed2001

[The effects of rhGH on macrophages in scalded mice].

OBJECTIVE: To investigate the effects of rhGH and IGF-1 on the CD14 mRNA expression and cytokine secretion of peritoneal macrophages (Mphi) in scalded rats. METHODS: Reverse-transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosordent assay (ELISA) were employed to observe the postburn changes of CD14 expression and cytokines secretion of the Mphi treated in vivo and in vitro by rhGH and IGF-1. RESULTS: It was demonstrated that in vivo postburn application of rhGH and IGF-1 could enhance the transcription of CD14 mRNA and the secretion of cytokines from the peritoneal Mphi in mice. But it seemed that there was no additive effect between the two factors. Additionally, rhGH (at 40 ng/ml) and IGF-1 (at all tested concentrations) could activate the secretion of TNF and IL-6 from cultured mice Mphi in vitro. CONCLUSION: Postburn application of rhGH might activate Mphi by IGF-1 induction, enhancing Mphi CD14 expression, which promoted more secretion of cytokines, and promote the enhancement of immune function.

Animals↗

PubMed2001

[The study of low dose radiation inducing hormesis effect on hematopoietic system].

OBJECTIVE: To study the hormesis effect on hematopoietic system induced by low dose radiation. METHOD: CFU-GM and BFU-E were cultured in methylcellulose semi-solid culture system, levels of GM-CSF and IL-3 were assayed by ELISA and mRNA levels of GM-CSF, G-CSF, IL-3 by in situ hybridization, narrow line hybridization and Northern blot. RESULTS: (1) The in vitro yields of CFU-GM and BFU-E from radiated mice was higher than that from the control. (2) The serum protein level of GM-CSF increased obviously than that of controls; (3) mRNA levels of GM-CSF and G-CSF were also increased. CONCLUSION: There is hormesis effect on hematopoietic system induced by low dose radiation, which may be related to the increasing of cytokines.

Animals↗

PubMed2001

[Clinical study of P-gp, and bcl-2 protein expression in non-Hodgkin's lymphomas patients].

OBJECTIVE: To investigate the relationship between the expression of P-gp, P26-bcl-2 and the prognosis in intermediate and high grade non-Hodgkin's lymphomas (NHL). METHODS: Sixty cases of intermediate and high grade NHL were retrospectively reviewed using immunohistochemical method. All patients were received CHOP chemotherapy over 4 courses. RESULTS: P-gp was identified in 15 and P26-bcl-2 in 25 cases. The 3-year survival rates for patients with P26-bcl-2 (+) and P26-bcl-2 (-) were 37.64% and 76.80%, respectively (P < 0.005), and for patients with both positive P-gp and P26-bcl-2 and both negative were 15.38% and 48.48%, respectively (P = 0.038). CONCLUSIONS: There is direct relationship between the P-gp, P26-bcl-2 protein expression and the prognosis in intermediate and high grade non-Hodgkin's lymphoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

[Measurement of central respiratory drive and inspiratory muscles strength in patients with uremia].

OBJECTIVE: To investigate the changes of central respiratory drive and inspiratory muscles function in patients with uremia. METHODS: We performed the measurement of forced vital capacity (FVC), maximal voluntary ventilation (MBC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), maximal midexpiratory flow (MMEF), expiratory flow of 25 per cent of FVC (V25), lung carbon monoxide diffusing capacity (DLco), maximal inspiratory mouth pressure (MIP) and airway occlusion pressure (P0.1) in 25 patients with uremia and 20 normal subjects. RESULTS: In patients with uremia, the FVC, MBC, FEV1, PEF, MMEF and V25 which reflect the lung ventilatory function and the DLco which reflects the lung diffusing function were significantly lower than those in normal subjects. The patients' MIP which reflects inspiratory muscles strength was significantly lower and their P0.1 which reflects the central respiratory drive was significantly higher, compared with the normal subjects'. CONCLUSION: Our findings suggest that on the basis of the disorder of ventilation and diffusing function of the lungs, the inspiratory muscles function of the patients with uremia is significantly decreased and the central respiratory drive of the patients is increased.

Aged↗

PubMed2001

[Establishment and identification of squamous cell lines carcinoma of tongue transferred with anti-sense cyclin A gene].

OBJECTIVE: The aim of this study is to investigate the relationship between cyclin A and cycle regulation of squamous cells carcinoma of tongue, and to provide basis for cancer gene therapy. METHODS: Eukaryocyte expression vector (pAS-A) containing anti-sense and the full-length human cyclin A complementary DNA (cDNA) (1.77 kb) was constructed and was transferred into squamous carcinoma of the tongue cell line (Tca8113) by Lipofect AMINETM introduction. The positive cell clones were selected with G418. Transcription of Neo gene mRNA and cyclin A mRNA were determined by in situ hybridization. The stable expression of anti-sense cyclin A in the Tca8113 cell line was determined using immunohistochemical methods. RESULTS: After G418 selection, cells transferred anti-sense cyclin A were obtained successfully. The positive cells of in situ hybridization of specific-stained Neoprobe were observed in cells transferred eukaryocyte expression vector. The positive cells of in situ hybridization of cyclin A in cells transferred anti-sense cyclin A were significantly fewer than those in cells transferred cyclin A. The positive rate of cyclin A immunohistochemical stain in cells transferred anti-sense cyclin A was significantly lower than that in cells transferred cyclin A. CONCLUSION: Human anti-sense cyclin A gene is stably expressed in the Tca8113 cell lines.

Carcinoma, Squamous Cell↗

PubMed2001

[Study on sampling preconcentration method combining electrostacking with isotachophoresis in capillary electrophoresis].

A sampling preconcentration method combining electrostacking with isotachophoresis is presented in this paper. The optimum conditions for electrostacking and isotachophoresis were investigated. With the preconcentration conditions of 70 s electrostacking and 40 s isotachophoresis, two medicines, propranolol and metoprolol, with similar structures were separated by capillary zone electrophoresis. The working voltage for all the steps was 15 kV. Being adjusted to pH 4.0, 30 mmol/L NaAc-HAc, 30 mmol/L beta-alanine-HAc and 1.5 mmol/L NaAc-HAc were employed as the background, viz. leading, terminating and sample buffer solutions respectively. In comparing with the conventional electro-migration injection, the enhancement factors in peak height of the present method were about 250 and 160 for propranolol and metoprolol respectively. Total analysis time was similar to that of the conventional one.

Electrolytes↗

PubMed2001

[Study of the adsorption properties in chromatographic separation of the citric acid].

A new method studying the change of thermodynamic properties at different temperatures to screen suitable stationary phases for chromatographic separation of the citric acid (CA) on an analytical column has been developed. The applied method is mainly based on using CA with a series of solute concentrations (0 g/L-250 g/L) as mobile phase to seriously overpass the unloaded stationary phase to find the breakthrough curves of CA. The adsorption isotherms were calculated from the retention times of breakthrough curve. The bed porosity of column was calculated from the elution time of a peak of the blue dextran as non-adsorbed tracer. The stationary phase, which has been selected through this method, for the separation of CA from fermentation broth, showed a very high adsorption capacity for CA, even under very low concentrations, so it can even be used in the separation and purification process of minute amounts of CA. The separation effect of this stationary phase for citric acid can be greatly enhanced through the technique of change of temperature. This new separation process can shorten the old process path, improve the yield of finished products more than 10%, and reduce the cost more than 10%. At the same time, the pollution of the production of citric acid can be reduced. It turned out that this method will play an important role in the synthesis of stationary phase for the separation of citric acid and the study of its structure.

Adsorption↗

PubMed2001

[Cloning and expression of the envelope glycoprotein gD gene of pseudorabies virus EA strain].

The envelope glycoprotein gD gene of pseudorabies virus Ea strain was cloned via PCR technique. Sequence analysis displayed 98% nucleotide sequence homology and 97% deduced amino acid sequence homology between our cloned gD gene and PRV Rice strain gD gene. The recombinant transfer plasmid pSX35A-gD was obtained by inserting D gene into the baculovirus transfer vector pSX35A with whole-phase promoter cassette, then transfected insect cell Hi5 with linearized AcMNPV-OCC- virus DNA, and formed recombinant baculoviruses AcMNPV-OCC(+)-gD by homologous recombination in insect cell. Recombinant baculoviruses infected insect cell Hi5 after being purified by plaque assay. Both SDS-PAGE and Western-blotting showed glycoprotein gD with a molecular weight of about 47 kD was expressed specifically, product was about 6.2% of total cellular protein, and expressed gD was of immunogenicity.

Animals↗

PubMed2001

[Expression of human interleukin-12 in Baculovirus expression system].

Human Interleukin-12 (hIL-12) is a key immunoregulatory cytokine and the only heterodimeric cytokine found by far. It is a disulfide-linked heterodimer composed of a 35 kD light chain (P35) and a 40 kD heavy chain (P40). Two recombinant transfer vector plasmids pAcAB3-p35 (including hIL-12 p35 gene) and pAcAB3-p40 (including hIL-12 p40 gene) were constructed and co-transfected the insect cells Sf9 with AcNPV BaculoGold Linearized Baculovirus DNA. The obtained recombinant viruses, AcNPV-OCC(-)-hiL-12 (p35) and AcNPV-OCC(-)-hIL-12 (p40), were used to infect the Sf9 cells separately, and the supernatants of culture and cell lysate were examined by using SDS-PAGE and Western blot. Results showed that both hIL-12 p35 and p40 gene were successfully expressed in insect cells and secreted. The expression productions had immunogenicity.

Animals↗

PubMed2001

[Expression of human leukemia inhibitory factor gene in Pichia pastoris].

The 575 bp artificial synthesized human leukemia inhibitory factor (hLIF) gene was cloned into vector pPICZ alpha A and the constructed expression vector pPICZ alpha A-hLIF was linearized by SacI and transformed into Pichia pastoris X-33. After the screening for Mut phenotype and the PCR analysis of the transformants, hLIF gene expressed in Pichia pastoris. SDS-PAGE and Western blot analysis of the culture supernatants showed that hLIF gene could express as 58.5 kD protein with the desired immunogenicity. Density scanning of the SDS-PAGE gel revealed that the targeted protein accounted for 32.8% of the total protein in the supernatants. The expressed products can inhibit the clone formation of murine's teratoma cells.

Animals↗