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Biomedical subjects

Tao Xia

Publications and source records attributed to Tao Xia.

26 records · Page 2Linked to original sources
PubMed2004

[Preparation and component analysis of tea pigments].

OBJECTIVE: To prepare tea pigments. METHODS: Tea pigments are prepared by solvent extraction from Sri lanka black tea. RESULTS: Tea pigments contains the components as follows: caffeine 1.77%, epigallocatechin 1.37%, catechin 1.20%, epicatechin 9.55%, epigallocatechin gallate 10.52%, epicatechin gallate 9.94%, theaflavin 10.34%, theaflavin monogallate 9.57%, theaflavin digallate 4.81%, thearubigin about 40.93%. CONCLUSION: The best proportions of the compound that are obtained with HPLC analysis.

Biflavonoids↗
PubMed2003

[Effect evaluation of three cell culture models].

Primary rat hepatocytes were cultured using three kinds of models in vitro and the enzyme leakage, albumin secretion, and cytochrome P450 1A (CYP 1A) activity were observed. The results showed that the level of LDH in the medium decreased over time in the period of culture. However, on 5 days, LDH showed a significant increase in monolayer culture (MC) while after 8 days LDH was not detected in sandwich culture (SC). The levels of AST and ALT in the medium did not change significantly over the investigated time. The basic CYP 1A activity gradually decreased with time in MC and SC. The decline of CYP 1A in rat hepatocytes was faster in MC than that in SC. This effect was partially reversed by using cytochrome P450 (CYP450) inducers such as omeprazol and 3-methylcholanthrene (3-MC) and the CYP 1A induction was always higher in MC than that in SC. Basic CYP 1A activity in bioreactor was keeped over 2 weeks and the highest albumin production was observed in bioreactor, and next were SC and MC. In conclusion, our results clearly indicated that there have some advantages and disadvantages in each of models in which can address different questions in metabolism of toxicants and drugs.

Albumins↗
PubMed2002

Qualitative study of three cell culture methods.

Primary rat hepatocytes were cultured using different in vitro models and the enzyme leakage, albumin secretion, and cytochrome P450 1A (CYP 1A) activity were observed. The results showed that the level of LDH was decreased over time in culture. However, on day 5, LDH showed a significant increase in monolayer culture (MC) while after day 8 no LDH was detectable in sandwich culture (SC). The levels of AST and ALT did not change significantly over the investigated time. The CYP 1A activity was gradually decreased in a time-dependent manner in MC and SC. The decline of CYP 1A was faster in MC than in SC. This effect was partially reversed by using cytochrome P450 (CYP450) inducer such as Omeprazol and 3-methylcholanthrene (3-MC) and the CYP 1A induction was always higher in MC than in SC. In bioreactor basic CYP 1A activity was preserved over 2 weeks and the highest albumin production was observed in bioreactor followed by SC and MC. Taken together, it was indicated each investigated model had its advantages and disadvantages. It was also underlined that various in vitro models may address different questions.

Albumins↗
PubMed2002

Identification and characterization of a NaCl-inducible vacuolar Na+/H+ antiporter in Beta vulgaris.

We have cloned, by RT-PCR and the use of degenerate oligonucleotide primers, a Na+/H+ antiporter from Beta vulgaris that is homologous to NHX1 of Arabidopsis thaliana and is a member of the family of recently cloned plant NHX-genes. This antiporter, BvNHX1, partially complements the salt-sensitive phenotype of a Deltaena1-4Deltanhx1 yeast strain. Antibodies were raised against a central portion of the BvNHX1 open reading frame that was predicted from the cloned cDNA. This antiporter was found to be highly enriched in tonoplast membranes isolated from plant tissues. BvNHX1 transcript abundance increased after salt treatments, in both suspension-cell cultures and whole plants. BvNHX1 protein abundance in the tonoplast-enriched membranes was also elevated after salt treatments. The vacuolar Na+/H+ antiporter activity increased up to 3-fold when the cell were exposed to 100 mM NaCl. The increase in protein abundance in response to the salt treatment, together with the salt-induced vacuolar Na+/H+ antiporter activity in B. vulgaris suggests that BvNHX1 plays an important role in salinity tolerance.

Journal Article↗
PubMed2002

[Effects of selenium and zinc on rat renal apoptosis and change of cell cycle induced by fluoride].

OBJECTIVE: This study was conducted to study the effects of sodium fluoride (NaF) on rat renal apoptosis and proliferation, the antagonistic effect of selenium-zinc preparation (Se-Zn) to NaF. METHODS: Wistar rats were provided with distilled water containing NaF (50 mg/L) and administered by gavage with different dosed of Se-Zn for six months. Kidney cell apoptosis and the cell cycle of proliferation were detected by TUNEL (TdT-mediated dUTP Nick End Labelling) and flow cytometry. RESULTS: NaF caused rat renal apoptosis, reduce the cell number of G(2)/M period in cell cycle and decrease the relative content of DNA significantly. Se-Zn inhibited the effects of NaF on apoptosis and increased the cell number of G(2)/M period in cell cycle, but failed to increase relative content of DNA. CONCLUSION: It was suggested that NaF could induce apoptosis and change the cell cycle in rat renal cells and Se-Zn could antagonize apoptosis and the changes of cell cycle induced by NaF.

Animals↗
PubMed2002

[Studies on DNA damage and apoptosis in rat brain induced by fluoride].

OBJECTIVE: To explore the DNA damage effects and apoptosis in brain cells of rats induced by sodium fluoride. METHODS: SD rats were divided into two groups, i.e. control group and fluoride treated group, which were injected intraperitoneally with distilled water and sodium fluoride (20 mg.kg(-1).d(-1)) respectively. On the hand, 5 mmol/L NaF were used in in vitro study. Single Cell Gel Electrophosis (SCGE or Comet Assay) was utilized to measured DNA damage and apoptosis was detected by the TUNEL method and Flow Cytometry (FCM). RESULTS: The DNA damage in pallium neurons in rats of the fluoride group was much more serious compared with those of the control group, with the Ridit value being 0.351 and 0.639 respectively (P < 0.01) in vivo, and 0.384 4 and 0.650 1 respectively (P < 0.01) in vitro. TUNEL positive cells were found in pallium, hippocampus and cerebellar granule cells in rats of fluoride group, whereas those in the control group were rare. It was demonstrated by FCM results that the percentages of apoptotic cells both in pallium and hippocampus were significantly higher (P < 0.01) in rats of fluoride group (27.12 +/- 3.08, 34.97 +/- 5.46) than those in control group (4.63 +/- 0.98, 5.35 +/- 0.79), (P < 0.01). CONCLUSION: Sodium fluoride could induce DNA damage and apoptosis in rats brain.

Animals↗
PubMed2002

[Effects of selenium and fluoride on apoptosis and lipid peroxidation in human hepatocytes].

OBJECTIVE: To study the influence of selenium and fluoride on apoptosis and lipid peroxidation in human hepatocytes in vitro. METHODS: The apoptosis, cell cycle, GSH content and lipid peroxides (LPO) level in human hepatocytes, LPO level and LDH, AST and ALT activity in cell culture supernatants were investigated after hepatocytes were incubated with selenium and/or fluoride for around 12 hours periods in vitro. RESULTS: The percentage of hepatocyte apoptosis bodies (15.557 +/- 2.056)%, the number of cells in S phase (4.823 +/- 0.454)% and LPO level in liver tissue and supernatant [(2.884 +/- 0.589) and (3.547 +/- 0.561) nmol/L MDA/mg.prot, respectively], AST and LDH activity in supernatants (91.1 +/- 36.4 and 140.4 +/- 7.6 U/L, respectively) in the fluoride treated group was higher than the control group [(10.313 +/- 1.023)%, (3.253 +/- 0.743)%, (1.473 +/- 0.401) nmol/L MDA/mg.prot, (1.694 +/- 0.443) nmol/L MDA/mg.prot, (54.5 +/- 3.2) U/L and (126.4 +/- 2.6) U/L, respectively], The GSH content in live tissue [(4.225 +/- 0.781) microgram/mg.prot] is lower than control group [(7.595 +/- 1.042) microgram/mg.prot]. Selenium treatment reduced these kinds of toxicity of fluoride through raising GSH content, reducing LPO level, LDH and AST activity and percentage of apoptosis bodies. CONCLUSIONS: Selenium can antagonist apoptosis and lipid peroxidation of hepatocytes induced by fluoride.

Alanine Transaminase↗