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Biomedical subjects

Y Chen

Publications and source records attributed to Y Chen.

At least 991 records · Page 55Linked to original sources
PubMed2000

[Separation and determination of baicalin in prescriptions containing Scutellaria baicalensis Georgi by HPCE].

Qingkailing Oral Tonic and Shuanghuanglian Oral Tonic are two kinds of complex formlae of Chinese traditional patent medicine, and both contain Scutellaria baicalensis Georgi. Baicalin is referred to the main active component with functions of dispelling wind-heat to reduce fever and detoxicating, and takes effect on uppering respiratory tract infection and tonsillities. In this work a high performance capillary electrophoresis (HPCE) method was established for separation and quantitative analysis of baicalin in prescriptions containing Scutellaria baicalensis Georgi, based on the mode of capillary zone electrophoresis. Electrophoretic conditions are as follows: uncoated fused silica capillary (34.8/39.5 cm x 50 microns i.d.), 40 mmol/L borax buffer(pH 9.0), applied voltage 17 kV, polarity anode (inlet) to cathode (outlet), temperature 25 degrees C, detection wavelength 285 nm, injection 68.95 kPa x s. Under the optimum conditions, baicalin was separated successfully from other components within 15 minutes. The relative peak area of baicalin increased linearly with the increase of its concentration in the range of 10-640 mg/L. The recoveries were (100.31 +/- 1.98)% for Qingkailing Oral Tonic and (100.60 +/- 2.36)% for Shuanghuanglian Oral Tonic. The analytical results demonstrate the method is simple, rapid and well reproducible, and can be used as a reliable tool for the quality control of Chinese traditional medicines containing Scutellaria baicalensis Georgi.

Anti-Infective Agents↗
PubMed2000

[Separation and determination of glibenclamide in xiaotangling tablets by micellar electrokinetic capillary chromatography].

A high performance capillary electrophoresis method has been developed for separation and quantitative analysis of glibenclamide in Xiaotangling tablets. Electrophoretic conditions were as follows: micellar electrokinetic capillary chromatography (MECC) mode, trimethoprimum as internal standard, uncoated fused silica capillary (34.8 cm/39.5 cm(effective/total length), 50 microns i.d.), 25 mmol/L borax-30 mmol/L SDS(pH 9.0), applied voltage 17 kV, (+)-->(-), temperature 28 degrees C, detection wavelength 228 nm, pressure injection 68.95 kPa.s. Glibenclamide was separated successfully from other components within 14 minutes under the optimum conditions, and the relative peak area of glibenclamide increased linearly with the increase of its concentration within the range of 25 mg/L-275 mg/L. The recovery was (100.6 +/- 1.4)%. The method is simple, rapid and well reproducible, and can be used as a reliable tool for the quality control of Chinese traditional medicine containing glibenclamide.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2000

[Transcription regulation of intercellular adhesion molecule (ICAM-1) on lymphatic endothelial cells of rectum adenocarcinoma of human].

This study inquired into the mechanism of cancer lymphatic metastasis. The immunohistochemistry method and DNA hybridization in situ were employed in examining the peritumoral rectum tissues and metastatic lymph nodes from 8 rectum carcinoma patients and the rectum tissues and lymph nodes from 5 normal subjects. The results showed that the proteins of ICAM-1 and nuclear factor kappa B (NF kappa Bp65) were expressed on the lymphatic endothelial cells of the rectum adenocarcinoma patients, and there was a NF kappa B binding consensus sequences on ICAM-1 promoter in lymphatic endothelial cells of rectum adenocarcinoma patients. When DIG-AKP labeled 38 bp oligonucleotide probe was used, there was no the expression of ICAM-1 and NF kappa Bp65 on the lymphatic endothelial cells of the normal human lymph node and rectum tissues. It is suggested that the activation of ICAM-1 promoter may critically depend on NF kappa Bp65 homodimers or heterodimers binding to a variant kappa B site on the lymphatic endothelial cells of the rectum adencarcinoma of human. These observations may indicate the potential roles of NF kappa B in cancer metastasis, thus giving clues to facilitate the development of a novel anti-metastasis strategy, that is obstruction the NF kappa B-activation pathways.

Adenocarcinoma↗
PubMed2000

[The expression of trkC in spared dorsal root ganglion following unilateral dorsal root rhizotomy].

This study sought to explore the expression of trkC in spared dorsal root ganglion(DRG) following unilateral dorsal root rhizotomy. 15 cats were divided into three groups: the intact group, the 3-day and 10-day groups after operation (unilaterral L1-L5 DRG and L7-S2 DRG were sectioned, but L6 DRG was spared). The animals were sacrificed on the 3rd day and 10th day after operation, respectively. The L6 DRG from the three groups were taken and cut into frozen sections (20 microns). The sections were stained using specific antiserum for trkC by the immunohistochemical ABC method. The numbers of large sized neurons (> 57 microns) and small sized neurons (< 42 microns) for trkC-IR were counted respectively. The results showed that the number of positive large sized neurons for trkC of the 10-day group after operation decreased significantly than that of the intact group and the 3-day group after operation, while the number of positive small sized neurons for trkC of the 10-day group increased apparently than that of the intact group and the 3-day group after operation (P < 0.05). This experiment demonstrated that unilateral partial dorsal root rhizotomy could change the expression of trkC might in large neurons and small sized neurons, and the results suggested that trkC might involve in the spinal cord plasticity following partial dorsal root rhizotomy.

Animals↗
PubMed2000

[Study on the production of beta-mannanase by Bacillus M50].

Bacillus sp. M50 produced beta-mannanase efficiently in the medium composed of 4% konjac powder, 1.0% (NH4)2SO4 and 0.35% Na2CO3. Fermentation of beta-mannanase by Bacillus sp. M50 has been carried out in 100 L tank. The temperature, ventitation quantity and agitation speed were 30-32 degrees C, 1:0.75 vvm and 220 r/min respectively. the fermentation cycle was 28 h and the highest beta-mannanase activity was 330 u/mL. The optimal temperature and pH for beta-mannanase reaction were 50 degrees C and 6.0 respectively. It was stable at pH 4.0-7.0 and below 50 degrees C. The activity of the enzyme was strongly inhibited by Fe3+, Al3+, EDTA, Hg2+ and slightly stimulated by Ba2+, Mn2+. Treatment of ramie-fibers with crude enzyme preparations from Bacillus sp. M50 showed a good degradation for hemicellulose of ramie-fibers residues.

Bacillus↗
PubMed2000

[Effect of sugars and pH on the fermentation of decane 1,10-dicarboxylic acid].

Some sugars, such as lactose, maltose, raffinose, glucose etc. can increase the purity of DC12 compared with sucrose. The value of pH can affect the process of producing DC12. Controlling the pH value between 7.5-8.0 can highly improve the production of DC12. Candida tropicalis can symport the DC12 with H+ to the outside of the cell.

Candida tropicalis↗
PubMed2000

[Detection of Neisseria gonorrhoeae(NG), Chlamydia trachomatis(CT) and Ureaplasma urealyticum(UU) by multiple primer PCR].

For the detection of Neisseria gonorrhoeae(NG), Chlamydia trachomat is(CT) and Ureaplasma urealyticum(UU) in urogenital infection in one specimen, multiple primer PCR was used in 156 sex transmitted disease patients, it was shown that in 156 specimens there were 40 NG positive and 31 CT positive and 27 UU positive, 10 NG + CT positive, 4 NG + UU positive, 3 CT + UU positive and 2 NG + CT + UU positive respectively. The results were in correspondence with each other. It is suggested that multiple primer PCR is a quick, sensitive, simple and specific technique which can be applied in clinical test.

Animals↗
PubMed2000

[L-lactic acid fermentation by immobilized Rhizopus oryzae in a three-phase fluidized-bed].

L-lactic acid fermentation in a three-phase fluidized-bed bioreactor was studied by using immobilized Rhizopus oryzae cells with polyurethane particles as supporter. The results indicated that the immobilized cells were stable after used for 8 batches repeatedly. The rate and the yield of lactic acid fermentation with glucose as carbon source were 19.1 g h-1.L (bead)-1 and 82.5%, respectively. With the hydrolyzate of corn cob residue from xylose manufacturer by cellulase hydrolysis, the yield of lactic acid reached 71.9%.

Bioreactors↗
PubMed2000

[Effect of lysophosphatidylcholine on endothelial cell surface expression of adhesion molecules].

Extensive monocyte recruitment is an early phenomenon associated with the development of atherosclerotic lesion, in which adhesion molecules expressed by endothelial cell play an active role. In this study we examined the effects of Lysophosphatidylcholine(Lyso-PC), a major phospholipid component of atherogenic lipoproteins, on the expression of adhesion molecules for monocytes, such as intercellular adhesion molecule-1(I-CAM-1), endothelial-leukocyte adhesion molecule-1(E-selectin) and vascular cell adhesion molecule-1(VCAM-1), in cultured human umbilical vein endothelial cells(HUVECs). After treating HUVECs with different concentration Lyso-PC at different times, the expression of adhesion molecules on the surface of HUVECs induced by Lyso-PC were analyzed using flow cytometry. The results showed that compared with control group, the surface expression of ICAM-1 and VCAM-1 was increased on HUVECs treated with Lyso-PC. ICAM-1 and VCAM-1 expression was maximally induced 1 h after stimulated with 50 micrograms/mg Lyso-PC, compared to basal values. At the 3 h after stimulation, ICAM-1 dropped to basal level while VCAM-1 dropped below to basal level. The effects of Lyso-PC on E-selection expression were negligible with in 3 h. However, at the 3 h of treatment with 50 micrograms/ml, the E-selectin expression on HUVECs began to be up-regulated significantly. We conclude that in addition to its monocyte chemoatractant activity, Lyso-PC can selectively induce ICAM-1 and VCAM-1 expression on the surface of HUVECs. Lyso-PC may play an important role in monocyte recruitment into athersclerotic lesions.

Cells, Cultured↗
PubMed2000

[Synthesis of droloxifene citrate and its new bioactivity].

AIM: To investigate a feasible synthetic procedure of droloxifene and study on its new bioactivities. METHODS AND RESULTS: Droloxifene was synthesized using methoxybenzene and phenylacetic acid as starting materials, via Friedel-Crafts acylation, alkylation, demethylation, etherification, Grignard addition, elimination-dehydration, conversing configuration and forming citrate, totally 8 steps, overall yield 14.7% (9.2%). By pharmacological test, droloxifene citrate shows two new bioactivities: (1) obvious effect on reversing the MDR of K562/A02 cells and modulating mdrl, GST pi and TopoII alpha expression. (2) inducing apoptosis in cultured rat luteal cell. CONCLUSION: The improved synthetic procedure is shorter than the reported method by two steps and has advantages of simple separation, purification and conversion of configuration; easily available starting materials and reagents; concise operation. Two new bioactivities on reversing MDR and inducing apoptosis of luteal cell offered a clue in new drugs research and widened clinic application of droloxifene.

Animals↗
PubMed2000

[Inhibition of extracts of ampelopsis sinica roots on DHBVsAg in sera of ducklings].

The ducklings, which are infected with Duck HBV to produce DHBVsAg in sera in advance, are treated with extracts from Ampelopsis sinica roots and some of them are treated with interferon alpha (INF) as positive control group. According the titer of DHBVsAg in Ducklings sera and the results of observing the tissues of the duckling's livers, it is demonstrated that the extracts of Ampelopsis sinica roots possess a certain action inhibiting DHBV and the action is enduring.

Ampelopsis↗
PubMed2000

Spatio-temporate expression of P53, Bcl-2 and Fas in the retina of RD, Rds and C3H mice.

PURPOSE: To investigate the expression status of p53, Fas and bcl-2 in the development of retinal degeneration in C3H, rd and rds mice. METHODS: Expression of p53, Fas and bcl-2 in the retina of rd, rds and C3H mice as well as in normal C3B mice in different periods was examined by immunohistochemical technique. RESULTS: The expression of Fas and p53 was not detected in normal C3B mice. Fas and p53 were expressed in the ganglionic layer in the early stage and then in the inner nuclear layer, while the scale and intense increased in the ganglionic layer. There is no difference of bcl-2 expression between the normal mice and mice with retinal degeneration. CONCLUSION: Fas and p53 may be involved in the retinal cell death in rd, rds, and C3B, but bcl-2 may not. It is unknown why p53 and Fas appeared first in ganglion layer but not in the outer nuclear layer where retinal cells death was noticed in early stage.

Animals↗
PubMed2000

[Applications of micromechatronics in minimally invasive surgery].

With the development of Micro Electro Mechanical System(MEMS), it's application in the fields of biomedical engineering becomes a vital consideration. This paper describes the advantages of Minimally invasive Surgery (MIS) and its applications. A novel medical endoscope driven by micro robot is also introduced.

Biomedical Engineering↗
PubMed2000

[Preparation and identification of monoclonal antibodies against human apoptosis-related protein TFAR19].

OBJECTIVE: To obtain mouse anti-human TFAR19 monoclonal antibodies for further study of the structure and function of the apoptosis-related protein TFAR19. METHODS: BALB/c mice were immunized with recombinant human TFAR19, hybridoma cells were screened by cell fusion and subcloning approach. The monoclonal antibodies were identified by ELISA and Western blotting. RESULTS: Three hybridoma cells (C1, C10, 2C12) stable in secreting anti-TFAR19 monoclonal antibodies were obtained. The monoclonal antibodies showed high specificity and high titer to TFAR19 with various affinity. All of them belong to IgG1 subclass. CONCLUSIONS: These monoclonal antibodies could bind specifically to TFAR19 protein.

Animals↗
PubMed2000

[Interactions between domains within the NH2- and COOH-terminal fragments of presenilins].

OBJECTIVE: To analyze the interactions between domains within the NH2- and COOH-terminal regions of presenilins. METHODS: The various constructions corresponding to NH2-terminal fragment (NTF) and COOH-terminal fragment (CTF) derivatives of presenilin 1 (PS1) and presenilin 2 (PS2) were generated by RT-PCR, and their interactions were assayed by yeast two-hybrid system. RESULTS: Domains within the NH- and COOH-terminal fragments of presenilins could directly interact with each other, and therefore form high molecular weight complex. The interaction site between domains within PS1 located at amino acid 361-447 of PS1 CTF, without the involvement of other partners. Similar interaction was not observed between PS11-360 and PS2341-448, PS2(1)-340 and PS1(361)-467. CONCLUSIONS: Intramolecular interaction between domains within the NH2- and COOH-terminal regions of presenilins may be critical to the folding and assembly of mature PS molecules.

Binding Sites↗
PubMed2000

[Impact of glutamine of gut permeability and clinical prognosis on the aging patients undergoing gastric-intestinal operation].

OBJECTIVE: To evaluate the impact of parenteral nutrition supplemented glutamine on aging patients undergoing gastric-intestinal operation. METHODS: 30 patients above 60 years old undergoing gastric-intestinal operation, a randomized double-blind protocol was designed, divided into two groups, received impact isocaloric parenteral nutrition. The study group received alanyl-glutamine [0.5 g/(kg.d)]. To observe plasma amino acids profile, nitrogen balance, intestinal permeability and clinical prognosis, examine clinical chemistry variables and observe the adverse reactions in order to find out its safety. RESULTS: The patients in both groups were comparable prior to the operation. The plasma glutamine level of study group is higher than the control group, it's cumulative nitrogen balance values were prior to the control group, L/M ratio was lower than the control group. The complications related to infection was observed more in the control group. No adverse reaction was observed in both groups. CONCLUSIONS: Ala-Gln-supplemented PN improved nitrogen balance and maintained intestinal permeability, reduced complications.

Aged↗
PubMed2000

[Somatostatin receptor subtype 2 mRNA expression in human gastric immortalized cell line and tumor cell lines].

OBJECTIVE: Inhibition of somatostatin on cell proliferation via somatostatin receptor subtype 2 (SS-R2), suggested this receptor subtype may be involved in tumor growth. Present study is to demonstrate whether SS-R2 was expressed in tumor cell lines extensively as well as in human gastric epithelia immortalized cell line. Meanwhile, the effect of p53 mutation on SS-R2 expression in gastric cancer cell line was also elucidated. METHODS: Full-length human somatostatin receptor subtype 2 cDNA was cloned by RT-PCR. Using cDNA as the probe and RT-PCR, expression of mRNA for SS-R2 in 9 cancer cell lines and human gastric immortalized cell line was detected. RESULTS: Data revealed that most cancer cell lines but a pancreatic cancer cell line expressed SS-R2 mRNA. CONCLUSION: Regardless whether p53 mutation or not in human gastric cancer cell lines, SS-R2 mRNA was transcribed.

Cell Line↗