Biomedical subjects

Xia Sun

Publications and source records attributed to Xia Sun.

26 records · Page 2Linked to original sources

PubMed2003

[Nutrient distribution and its controlling mechanism in the adjacent area of Changjiang River estuary].

In this paper, the nutrient distribution, its structural characteristic and controlling mechanism around the Changjiang River estuary during Autumn 1997 and Spring 1998 were discussed, and a clear seasonal variation of nutrient distribution and structure was observed in this area. The concentrations of NO3(-)-N, SiO3(2-)-Si, PO4(3-)-P, DOP, PP and TP in Autumn 1997 were higher than those in Spring 1998, and their average concentrations were 4.97, 11.6, 0.44, 0.26, 0.82 and 1.52 mumol.L-1, respectively. However, the concentrations of NO2(-)-N, NH4(+)-N, DON, PN and TN in Spring 1998 were higher than those in Autumn 1997, with the average concentration of 0.70, 2.26, 9.88, 7.88 and 25.3 mumol.L-1, respectively. The main form of phosphorus in Autumn 1997 was PP, with the percentage about 54%, while PO4(3-)-P was the dominant fraction, with about 51% of phosphorus in Spring 1998. Both DON and PN were the main fractions of nitrogen in Autumn 1997 and Spring 1998 as well. Due to the influences of the Changjiang dilution water, the concentrations of phosphate, nitrate and silicate along the coastal area were higher than those in the outer area, except the phosphate in Spring 1998, which mainly came from Taiwan warm current. It indicated that the distribution of the nutrients in the survey area was mainly controlled by the Changjiang dilution water and the high salinity sea-water from the Taiwan warm current, and the influence of Taiwan warm current on phosphate was larger in Spring than in Autumn.

China↗

PubMed2003

[Distributions of COD and petroleum hydrocarbons and their relationships with occurrence of red tide in East China Sea].

Based on the data of COD and petroleum hydrocarbons collected in the cruise from April 25 to May 2, 2002 in intensive red tide occurrence areas in East China Sea, the distribution of COD, and petroleum hydrocarbons and the eutrophication index(EI) were analyzed. The results showed that the EI and COD value were both high in coastal water, and decreased gradually away from shore. After the preliminary study on the relationships between correlative factors and occurrence of red tide, it was found that high EI and COD were necessary. There would be great chances for the red tide to break out under conditions that the EI was between 2.5 and 15 and COD concentration was between 0.8 to 1.4 mg.L-1 in seawater, along with the favorable temperature and salinity.

China↗

PubMed2003

[Nutrient distribution and its relationship with occurrence of red tide in coastal area of East China Sea].

Nutrient (NO3(-)-N, PO4(3-)-P, Sio3(2-)-Si, NH4(+)-N, etc.) concentrations in coastal area of East China Sea were measured during April 25 to May 2, 2002, and the relationship between the spatial distribution of the nutrients and the red tide occurrence in the studied area was analyzed. The results showed that compared to the 1st class seawater quality of the national standard, the concentrations of dissolved inorganic nitrogen (DIN) and PO4(-)-P were 46% and 60% higher, respectively, showing that the studied area, especially the Changjiang River estuary and the Hangzhou Bay, was at a disadvantage of eutrophication. Furthermore, the nutrient concentrations inshore were much higher than those offshore, and the isolines nearly paralleled with the coastline, meaning that the nutrient distributions were mainly influenced by terrestrial discharges. It also showed that the relatively high concentrations of nutrients, especially DIN and PO4(3-)-P, might result in the red-tide occurrence. However, the red tide did not occur in the area with the highest concentrations of the nutrients, further demonstrating that the eutrophication was not the unique environmental factor inducing red-tide occurrence.

China↗

PubMed2002

Early diagnosis of ataxia-telangiectasia using radiosensitivity testing.

OBJECTIVES: To utilize radiosensitivity testing to improve early diagnosis of patients with ataxia-telangiectasia (A-T). STUDY DESIGN: We established normal ranges for the colony survival assay (CSA) by testing cells from 104 patients with typical A-T, 29 phenotypic normal patients, and 19 A-T heterozygotes. We also analyzed 61 samples from patients suspected of having A-T and 25 patients with related disorders to compare the CSA with other criteria in the diagnosis of A-T. RESULTS: When cells were irradiated with 1.0 Gy, the mean survival fraction (microSF +/- 1 SD) for patients with A-T was 13.1% +/- 7.2% compared with 50.1% +/- 13.5% for healthy control patients. These data served to define a diagnostic range for the CSA (ie, <21%), a normal range (>36%), and a nondiagnostic intermediate range of 21% to 36%. The mutations of patients with A-T with intermediate radiosensitivity tended to cluster around the functional domains of the ATM gene. CONCLUSIONS: The CSA is a useful adjunctive test for confirming an early clinical diagnosis of A-T. However, CSA is also abnormal in other chromosomal instability and immunodeficiency disorders.

Ataxia Telangiectasia↗

PubMed2002

[Effect of lead acetate on the apoptosis and the expression of bcl-2 and bax genes in rat brain cells].

OBJECTIVES: To explore the effect of lead acetate on the apoptosis of rat brain neural cells and the relationship between the apoptosis and the bcl-2 as well as bax gene expression. METHODS: Lead acetate was given to SD rats by intraperitoneal injection for 5 days at the dosage of 25, 50 and l00 mg/kg body weight respectively. The rates of apoptosis and the expression of bcl-2 (Bcl-2) and bax (Bax) in neural cells from cerebral cortex, hippocampus and carebellum were measured respectively by flow cytometry (FCM). RESULTS: The rates of apoptosis in neural cells from cerebral cortex, hippocampus and cerebellum in every treatment group were significantly higher than that of control (P < 0.01), and there was a significant dose-response relationship (r = 0.998, 0.989 and 0.997 respectively). The expression of bcl-2 was significantly decreased, whereas bax was significantly increased, in neural cells from cerebral cortex, hippocampus and cerebellum in every lead acetate treatment group (FI) compared with the control group, and there was a significant dose-response relationship (r = -0.886, -0.787 and -0.832 respectively for bcl-2, r = 0.971, 0.988 and 0.991 respectively for bax). The value of Bcl-2/Bax in every treatment group decreased significantly compared with control, and there was a nice dose-response relationship (r = -0.863, -0.829 and -0.999, respectively). Correlation analysis showed that rates of apoptosis were inversely correlated with the expression of bcl-2 (r = -0.750, -0.509, and -0.667, respectively), whereas positively correlated with the expression of bax (r = 0.748, 0.56l, and 0.668, respectively). And there were inverse correlations between the rates of apoptosis and Bcl-2/Bax expression. CONCLUSION: Lead may induce apoptosis in rat brain neural cells through the down regulation of bcl-2 and the up regulation of bax gene expression.

Animals↗

PubMed2002

[Quantitative genetic analysis and multiple trait selection of pharmaceutical composition on Ginkgo biloba L. leaves].

The China possesses more than 70% Ginkgo resources in the world. The purposes of this research are to collect fine seedling and grafting clones in China, to probe genetic law on flavone glycosides and terpenes on Ginkgo leaves, and select leaf-used cultivars of high-pharmaceutical composition. In this research, we have collected 87 clones from 13 provenances and have carried out randomized block experiment at Tancheng, Laizhou and Yaoxiang in Shandong Province. Flavone glycosides and terpenes were determined through HPLC method from an improved Van Beek (1991) techniques and Shimadzu Lc-10 AD (Japan). Data and breeding analyses were carried out through IBMPC and SPQG30 software. The results of variance analyses show that there are significant differences to flavone glycosides, terpenes in clones, and the law of genetic parameters on heritability (h2) and genetic variability coefficient (Gcv), is clone > sex > provenance to flavone glycosides in ginkgo leaves. The sigma g2, h2, Gcv and delta G' in male tree clone leaves are higher than female clone leaves on flavone glycosides. We have found that there is a maximum flavone content clone among males and a maximum terpene clone among females. The results of Q-cluster analyses are consistent with R-factor analyses of twenty higher terpenes clones. The results of index selection show that the ri.Y2, E(I) and CGS' of multiple traits selection including (gamma) trait are higher than single trait and multiple traits selection excluding gamma. The direct or index selection is more suited to leaf-used cultivars of Ginkgo. The genetic stability of each clone was appraised by Wricke's ecovalence method and Nassar & Huhu noparameter method. Flavone glycosides and terpenes are more than 2.09%-2.57% and 0.33%-0.41%, respectively, and we have selected four clones.

Breeding↗

PubMedDate not supplied

A new silymarin preparation based on solid dispersion technique.

Silymarin is a hepatoprotective agent that is poorly soluble in water. The present study describes a new preparation of solid dispersions in the form of "dripping pills" designed to enhance solubility. Dripping pills of silymarin were prepared at a 1:4 ratio by the traditional fusion method with the use of a mixture of silymarin and polyethylene glycol 6000 (PEG 6000). The prepared dripping pills were spherical and 3 to 4 mm in diameter, with an average weight of 30 mg per pill and with each pill containing 5 mg of silymarin. The dissolution rates of silymarin in dripping pill and of 3 other silymarin preparations, including Yiganling Film-Coating Tablet, Yiganling Sugar-Coating Tablet, and Legalon Capsule, were determined in pH 1.2 medium. The dissolution rate (T50) of the silymarin dripping pill was found to be significantly higher (by a factor of 7.5-11) than those of the other 3 preparations.

Polyethylene Glycols↗

PubMedDate not supplied

Preparation of indapamide slow-release pellets.

During the process of developing a slow-release formulation of indapamide, researchers created a drug-containing pellet coated with Eudragit RS100 (Rohm GMbH & Co. KG, Darmstadt, Germany) to control the rate at which the drug was released. The two main variables were the agglomerants used in the pellet preparation and the amount of Eudragit RS100 used to coat them. The optimal outcome was indicated by the greatest number of drug-containing pellets recovered through an 18- to 24-mesh sieve and a satisfactory 24-hour release curve. The kinetics of dissolution fit the Higuchi kinetics model. Stability tests of the drug pellets showed no notable changes in the rate of drug release, related substances (mean byproducts or impurities from interactions or decompositions), and drug content.

Biological Availability↗