Biomedical subjects

Juan Xu

Publications and source records attributed to Juan Xu.

28 records · Page 2Linked to original sources

PubMed2005

[Expansion ex vivo of human bone marrow mesenchymal stem cells and cord blood CD34+ cells].

The aim was to study the roles that the bone marrow mesenchymal stem cells (MSC) and cytokines play in cord blood CD34(+) cell expansion ex vivo and the influence of culture ex vivo on expression of the adhesive molecule of CD44. CD34(+) cells sorted from cord blood cells had been cultured in each well of 24 well culture plates containing culture medium supplemented with mesenchymal stem cells layer or/and cytokines for a week, and then all kinds of indexes of different groups were compared. The results showed that as for cord blood cell expansion, there was no significant difference between the groups with cytokines SDF-1alpha + SCF + TPO + FL and SCF + TPO + FL no matter if MSC layer existed or not. The groups with MSC layer and cytokines were superior to the corresponding groups without MSC layer. In addition, the expression of the adhesion molecule CD44 had no distinct change after culture. It is concluded that SDF-1alpha has no distinct influence on the effect of cytokines SCF + TPO + FL on cord blood cell expansion ex vivo. MSC enhance the effect of cytokines on cord blood cell expansion ex vivo. Such expansion ex vivo may not influence the expression of the adhesive molecule CD44 on cord blood cells.

Antigens, CD34↗

PubMed2004

Effect of foliar application of selenium on the antioxidant activity of aqueous and ethanolic extracts of selenium-enriched rice.

Selenium fertilizer was foliar applied to determine the effects of antioxidant activity of selenium-enriched rice assessed by alpha,alpha-diphenyl-beta-picylhydrazyl (DPPH) radical scavenging and the ferric thiocyanate (FTC) method. Results showed that selenium concentration in rice was significantly enhanced dose dependently. Aqueous or ethanolic extracts of rice displayed significantly higher antioxidant activity against lipid peroxidation. The activities of aqueous extracts were significantly higher than those of ethanolic extracts and increased with the increasing selenium concentration in rice. The DPPH assay showed that the kinetic behaviors of aqueous extracts were complex and slow, while ethanolic extracts reacted quickly with DPPH radical. Aqueous extracts of rice exhibited higher antiradical efficiencies than ethanolic extracts, and rice (1.275 mg Se kg(-)(1)) presented the lowest EC(50) values of 533.46 +/- 0.58 microg mL(-)(1). As compared to rice extracts, all of the reference antioxidants showed more than 4-fold antiradical efficiencies than rice extracts. This radical scavenging activity was significantly correlated with selenium concentrations in rice (R = 0.862, p < 0.05), while ethanolic extracts were inversely correlated with selenium concentration in rice.

Antioxidants↗

PubMed2004

Antioxidant activity of extracts of black sesame seed (Sesamum indicum L.) by supercritical carbon dioxide extraction.

Antioxidant activities of extracts derived from sesame seed by supercritical carbon dioxide (SC-CO(2)) extraction and by n-hexane were determined using alpha,alpha-diphenyl-beta-picylhydrazyl (DPPH) radical scavenging and linoleic acid system methods. The highest extracted yield was given at 35 degrees C, 40 MPa, and a CO(2) flow rate of 2.5 mL min(-1) by an orthogonal experiment. The yields of extracts increased with increasing pressure, and yields at 40 and 30 MPa were higher than that by solvent extraction at 46.50%. Results from the linoleic acid system showed that the antioxidant activity follows the order: extract at 35 degrees C, 20 MPa > BHT > extract at 55 degrees C, 40 MPa > extract at 55 degrees C, 30 MPa > Trolox > solvent extraction > alpha-tocopherol. The SC-CO(2) extracts exhibited significantly higher antioxidant activities comparable to that by n-hexane extraction. The extracts at 30 MPa presented the highest antioxidant activities assessed in the DPPH method. At 20 MPa, the EC(50) increased with temperature, which indicated that the antioxidant activity was decreased in a temperature-dependent manner. The significant differences of antioxidant activities were found between the extracts by SC-CO(2) extraction and n-hexane. However, no significant differences were exhibited among the extracts by SC-CO(2) extraction. The vitamin E concentrations were also significantly higher in SC-CO(2) extracts than in n-hexane extracts, and its concentrations in extracts corresponded with the antioxidant activity of extracts.

Antioxidants↗

PubMed2004

[Human complement components C4 and Bf polymorphisms and their complotypes in Guangdong Chinese Han population].

OBJECTIVE: To investigate the genetic polymorphism of human complement components C(4) and Bf and their complotype frequencies in Chinese Han population in Guangdong Province of China. METHODS: The genetic polymorphisms and complotypes of Bf, C(4)A and C(4)B, which were 3 components of HLA-III, were analyzed in 144 chromosomes of subjects from healthy Han families in Guangdong Province. RESULTS: Thirteen variable complotypes were identified, led by the complotypes of S(32), S(31), S(42) and F(42) among which strong linkage disequilibria were observed. The most common phenotypes were BFS, C(4)A(3), C(4)A(4), C(4)B(2) and C(4)B(1). CONCLUSION: The genetic polymorphism of C(4) and Bf and their complotypes have their own genetic predisposition in Chinese Han population in Guangdong Province.

Asian People↗

PubMed2003

Evaluation of antioxidant potential of aloe vera (Aloe barbadensis miller) extracts.

The polysaccharide and flavonoid concentrations of two-, three-, and four-year-old Aloe vera were determined, and their antioxidant activities were evaluated compared to BHT and alpha-tocopherol by the DPPH radical scavenging method and the linoleic acid system at 100 microg of soluble solids per mL of ethanol. The results showed that three-year-old Aloe vera contained significantly higher levels of polysaccharides and flavonoids than two- and four-year-old Aloe vera, and no significant differences in flavonoid levels were found between three- and four-year-old Aloe vera. All the aloe extracts showed significant antioxidant activity. The antioxidant activity of Aloe vera extracts and reference compounds followed the order: three-year-old Aloe vera > BHT > four-year-old Aloe vera > alpha-tocopherol > two-year-old Aloe vera. The three-year-old extract exhibited the strongest radical scavenging activity of 72.19%, which is significantly higher than that of BHT at 70.52% and alpha-tocopherol at 65.20%. These data suggest that the growth stage plays a vital role in the composition and antioxidant activity of Aloe vera.

Aloe↗

PubMed2003

Effect of selenium on the yield and quality of green tea leaves harvested in early spring.

Foliar applications of a fertilizer of selenite or selenate were carried out to determine the influence of selenium on the yield and quality of green tea leaves harvested in early spring. Numbers of sprouts and the yield were significantly increased by the application of selenium. The sweetness and aroma of green tea leaves were also significantly enhanced, and bitterness was significantly decreased by the application of selenium. However, no significant differences were found in sweetness, bitterness, and aroma between tea leaves fertilized with selenite and selenate. Se concentration was significantly increased by selenium fertilization, and tea enriched by sodium selenate had a significantly higher selenium content than did tea enriched by sodium selenite. Total amino acid and vitamin C contents were significantly enhanced by the application of selenium. Tea polyphenol contents were significantly decreased by fertilization with selenium. The marked difference of tea polyphenols was also found between applications of selenite and selenate.

Camellia sinensis↗

PubMed2003

Effect of selenium on increasing the antioxidant activity of tea leaves harvested during the early spring tea producing season.

This research was to determine the effect of foliar application of selenium on increasing the antioxidant activity of tea harvested during the early spring tea producing season using a alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical scavenging method and the linoleic acid system. The results showed that the radical scavenging ability of the tea extracts followed this order during the first 60 min: selenium-enriched tea obtained by fertilization with selenate > BHT > selenium-enriched tea obtained by fertilization with selenite > alpha-tocopherol > regular tea. Se-enriched tea obtained by fertilization with selenate exhibited the highest inhibition percentage of 84.29% at 30 min. Se-enriched tea extracts provided higher hydrogen-donating capabilities than regular tea and contrasts with BHT and alpha-tocopherol at the concentration of 100 microg of solids/mL of ethanol. There was a little change in the sequence of radical scavenging ability during the later 60 min: Se-enriched tea obtained by fertilization with selenate > Se-enriched tea obtained by fertilization with selenite > BHT > regular tea > alpha-tocopherol. The individual activity of tea extracts and references measured by the linoleic acid system showed that the tea extracts, BHT, and alpha-tocopherol manifested almost the same patterns of activity as the DPPH method. Tea enriched in selenium by fertilization with selenate still exhibited the highest inhibition activity of lipid oxidation, whereas alpha-tocopherol showed the lowest inhibition. The antioxidant activity of Se-enriched green tea harvested during the early spring tea producing season is enhanced compared to regular tea.

Antioxidants↗

PubMed2003

[The effect of granulocyte colony stimulating factor on T-cell subsets in peripheral blood and its correlation with the mobilization effect of CD34+ cells].

The objective was to observe the effect of G-CSF as a mobilizer of hematopoitic stem cells on the absolute counts of T-cell subsets in peripheral blood and their relevance with the mobilized CD34(+) cells. The examples of peripheral blood from 26 patients performed of autologous stem cell transplantation were taken before and after mobilization by G-CSF. Flow cytometry was used for detecting CD3(+), CD3(+)CD4(+), CD3(+)CD8(+), CD3(+)CD4(+)CD8(+) and CD3(+)CD4(-)CD8(-) cells. Concurrently, their correlations with mobilized CD34(+) cells in peripheral blood were compared. The results showed that after the mobilization by G-CSF, the amounts of CD3(+), CD3(+)CD4(+), CD3(+)CD4(+)CD8(+) and CD3(+)CD4(-)CD8(-) cells in peripheral blood increased by 2.23, 2.62, 2.99 and 10.96 fold respectively, but that of CD3(+)CD4(-)CD8(+) cells was nearly no changed (P = 0.243). The correlation coefficient of CD3(+)CD4(-)CD8(-) cells and mobilized CD34(+) cells was 0.796, (P = 0.000) and no correlation with other T-cell subsets. It was concluded that when CD34(+) cells were mobilized by G-CSF from bone marrow to peripheral blood, the absolute counts of the peripheral T-cell subsets got changed. The increase of CD3(+)CD4(-)CD8(-) cells had correlated with mobilization effect of CD34(+) cells into peripheral blood.

Adolescent↗

PubMed2002

Determination of selenium concentration of rice in china and effect of fertilization of selenite and selenate on selenium content of rice.

A method of hydride generation atomic fluorescence spectrometry was applied to the determination of the selenium concentration of regular polished rice in China and selenium-enriched polished rice obtained by foliar application of selenium-enriched fertilizer in the forms of selenite and selenate. The average selenium content of regular rice was 0.025 +/- 0.011 microg g(-)(1). On the basis of a daily dietary rice intake of 300-500 g suggested by the China Nutrition Society, the total selenium intake from regular rice was calculated to be 7.5-12.5 microg per person per day for an adult. The selenium contents of rice were significantly increased to 0.471-0.640 microg g(-)(1) by foliar application of selenium-enriched fertilizer at rate of 20 g of Se ha(-)(1) in the forms of sodium selenite and sodium selenate. The selenium content of rice by application of a fertilizer of selenate was 35.9% higher than that by a fertilizer of selenite, which showed that Se-enriched fertilizer in selenate exhibited greater efficiency in increasing Se content in rice products. The Se-enriched rice products can increase daily Se intake on average by 100-200 microg of Se per day by the consumption of 400 g of rice products if the Se level of rice products is controlled at 0.3-0.5 microg of Se g(-)(1). Because rice is a staple food in China, selenium-enriched rice obtained by bioenrichment of selenium to increase the Se content of rice could be a good selenium source for the population in selenium-deficient regions.

China↗

PubMed2002

[Immunophenotyping of eighty six children with acute lymphoblastic leukemia by three-color flow cytometry].

OBJECTIVES: To evaluate the specificity of three-color flow cytometry in childhood acute lymphoblastic leukemia (ALL) immunophenotyping. METHODS: Immunophenotyping was performed by three-color flow cytometry analysis using CD(45)/SSC gating. RESULTS: The percentage of blasts was correlated better with leukemic cell count compared with that of FSC/SSC, and the false positive results were low. Among eighty six cases of ALL, 95.3% was B-ALL, in which common-ALL and Pro-B-ALL were 76.8% and 6.1%, respectively, and 2.3% was T-ALL. CD(34)(+) and myeloid-associated antigen expression were observed in 57.0% and 34.9% of the cases, respectively, among which Pro-B-ALL was the commonest. CD(33) was more commonly expressed than CD(13) in Pro-B-ALL cases, but no difference in the expression between these two antigens in other subtypes. CONCLUSION: Gating of CD(45)/SSC eliminated effection of normal cells to blasts in bone marrow, with which the immunophenotyping results were more reliable.

Antigens, CD↗