Search PubMed⌕ Search

Biomedical subjects

Tao Bo

Publications and source records attributed to Tao Bo.

27 records · Page 2Linked to original sources
PubMed2004

Separation and determination of biphenyl nitrile compounds by microemulsion electrokinetic chromatography with mixed surfactants.

A mixture of six biphenyl nitrile compounds and three related substances with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The microemulsion system contained 100 mM sodium dodecyl sulfate (SDS), 80 mM sodium cholate (SC), 0.81% v/v heptane, 7.5% v/v n-butanol, 10% v/v acetonitrile, and 10 mM borate. The addition of SC, organic modifiers, sample preparation, and temperature all showed remarkable effects on the separation. The capacity factor (k) was calculated by using dodecyl benzene as the marker for microemulsion, and the calculated partition coefficient log P(o/w) of the solutes was in the range of 3.35-7.38. The log k values matched well with the log P(o/w) with a correlation coefficient of 0.96. In addition, the linear correlation coefficients of each compound between peak area and concentration were from 0.996 to 0.998 with the repeatability RSD value < 1.2% for migration time and < 4.8% for peak area, and the highest theoretic plate number was > 586000. MEEKC was compared with micellar electrokinetic chromatography (MEKC) indicating that the former method is more suitable for this separation and can be used for the quality control of biphenyl nitrile compounds in the synthesis of liquid crystals.

Biphenyl Compounds↗
PubMed2004

Phospholipid-lysozyme coating for chiral separation in capillary electrophoresis.

A phospholipid coating with lysozyme as chiral recognition reagent permeated into the phospholipid membrane was developed for the chiral capillary electrophoretic (CE) separation of D- and L-tryptophan. As a kind of carriers, coated as phospholipid membranes onto the inner wall of a fused-silica capillary, liposomes are able to interact with basic proteins such as lysozyme, which may reside on the surface of the phospholipid membrane or permeate into the middle of the membrane. The interaction results in strong immobilization of lysozyme in the capillary. Coatings prepared with liposomes alone did not allow stable immobilization of lysozyme into the phospholipid membranes, as seen from the poor repeatability of the chiral separation. When 1-(4-iodobutyl)-1,4-dimethylpiperazin-1-ium iodide (M1C4) was applied as a first coating layer in the capillary, the electroosmotic flow (EOF) was effectively suppressed, the phospholipid coating was stabilized, and the lysozyme immobilization was much improved. The liposome composition, the running buffer, and the capillary inner diameter all affected the chiral separation of D- and L-tryptophan. Coating with 4 mM M1C4 and then 1 mM phosphatidylcholine (PC)/phosphatidylserine (PS) (80:20 mol%), with 20 mM (ionic strength) Tris at pH 7.4 as the running buffer, resulted in optimal chiral separation with good separation efficiency and resolution. Since lysozyme was strongly permeated into the membrane of the phospholipids on the capillary surface, the chiral separation of D- and L-tryptophan was achieved without lysozyme in the running buffer. The effects of different coating procedures and separation conditions on separation were evaluated, and the M1C4-liposome and liposome-lysozyme interactions were elucidated. The usefulness of protein immobilized into phospholipid membranes as a chiral selector in CE is demonstrated for the first time.

Electrophoresis, Capillary↗
PubMed2003

[Effect of glucose-free treatment on the neural precursor cells in vitro].

OBJECTIVE: To investigate the survival, division, and differentiation of neural precursor cells (NPCs) following glucose-free treatment in vitro. METHODS: Cultured neonatal rat hippocampal NPCs were exposed to glucose-free media for 6 hours, and then were returned to regular media containing normal level glucose. At different time points after glucose-free treatment, trypan blue staining was used to determine cell viability, MTT assay to measure cell metabolic rate, 5'-bromo-deoxyuridine (BrdU) incorporation to determine the NPCs division, and immunocellulochemistry and western blot analysis to study the NPCs differentiation. RESULTS: (1) At different time points (0, 1, 7 d) after glucose-free treatment, NPCs viability decreased compared with NPCs control. On 0 and 1 d after glucose-free treatment, NPCs viability was higher than neurons viability. (2) On 0 and 1 d after glucose-free treatment, NPCs metabolic rates decreased significantly compared with NPCs control. On 0, 1, and 7 d after glucose-free treatment, NPCs metabolic rates were higher than that in neurons. (3) After glucose-free treatment, BrdU incorporation of NPCs was similar to NPCs control (P>0.05). (4) After glucose-free treatment, NPCs differentiation didn't change significantly (P>0.05). CONCLUSION: These findings demonstrated that glucose-free treatment impaired NPC's viability, but didn't affect the division and differentiation of NPCs.

Animals↗
PubMed2003

[Long-term effects of recurrent seizures in neonatal rats on NMDA receptor expression in the brain].

OBJECTIVE: To study the long-term effect of flurothyl-induced recurrent seizures in neonatal rats on cognition, seizure susceptibility, and NMDA receptor expression in adult rat brain. METHODS: Seizures were induced by inhalant flurothyl for 6 days, starting from postnatal day 6 (P6). On P60, rats were tested for spatial memory by using the Morris water maze task. Seizure threshold was examined by intraperitoneal injection of pentylenetetrazol (PTZ) on P75. Brain homogenates were made at the same time. Expression of NMDA receptor protein in cerebral cortex and hippocampus was examined with Western blotting analysis. RESULTS: Compared with the control group, flurothyl-treated rats showed significant spatial deficits in the Morris water maze on P60. There was no difference in seizure threshold. In the cerebral cortex of flurothyl-treated rats, the protein expressions of NR1, NR2A, and NR2B decreased significantly, but NR2C increased significantly. In the hippocampus of flurothyltreated rats, the protein expression of NR2A decreased significantly, the protein expression of NR2C increased significantly, and NR1 and NR2B were similar to that in the hippocampus of control group. CONCLUSION: Recurrent seizures in neonatal rats might cause long-term cognitive deficit and modify NMDA receptor subunit expressions in cerebral cortex and hippocampus of adult rats. This phenomenon raised the possibility that abnormal NMDA receptor expression might play an important role in long-term cognitive deficit induced by early life recurrent seizures.

Anesthetics, Local↗
PubMed2003

Investigation of the effect of space environment on the contents of atropine and scopolamine in Datura metel by capillary zone electrophoresis.

The seeds of Datura metel were carried aboard a retrievable satellite and exposed to space environment. The effects of space environment (weightlessness and ionizing radiation) on the contents of atropine and scopolamine in D. metel were investigated by using an effective capillary zone electrophoresis (CZE) method, which employed 50 mmol/l phosphate buffer (pH 8) containing 10% (v/v) tetrahydrofuran as the running buffer. The results showed that the contents of atropine and scopolamine varied to some extent, and the earth-control group has the lowest content of atropine. However, the variation of atropine and scopolamine contents in three groups was not obvious based on t-test. At the same time, the optimization of the separation was discussed in detail and the two compounds were completely separated within 10 min with satisfactory repeatability and calibration linearity.

Atropine↗
PubMed2003

Capillary electrophoretic behaviors of pharmacologically active xanthones from Securidaca inappendiculata with beta-cyclodextrin as a buffer additive.

The capillary electrophoretic (CE) behaviors of ten xanthones in the presence of beta-cyclodextrin (CD) are investigated, and apparent analyte-selector binding constants between beta-CD and the xanthones in the CE running buffer are calculated to elucidate the migration order. Also, the separation selectivity with beta-CD additive is compared with that of sulfated beta-CD additive. It is indicated that beta-CD can greatly change the separation selectivity of xanthones, and the electrophoretic behaviors of xanthones are rather different when using beta-CD from that when using sulfated beta-CD as an additive.

Buffers↗
PubMed2003

[Cortical neuron injury occurs following recurrent epileptiform discharges induced by magnesium-free treatment in vitro].

OBJECTIVE: To study cortical neuron injury following recurrent epileptiform discharges induced by magnesium-free treatment in vitro. METHODS: Cultured embryo cortical neurons were exposed to magnesium-free media for 3 h, then they were returned to regular media containing normal level magnesium. At different time after Mg(2+)-free treatment, trypan blue staining and determination of LDH activity were used to determine the cell viability, flow cytometry was applied to measure neuronal apoptosis, and MTT assay to study metabolic rate. RESULTS: (1) Neuronal morphology on light microscopy following Mg(2+)-free treatment showed that there were no prominent alterations. (2) At different time (6, 12, 72 h) after Mg(2+)-free treatment, neuronal viability by trypan blue staining and LDH activity showed modest changes compared with time-matched control in different culture days (6, 12, 17 d) (P > 0.05). (3) Cell apoptosis increased mildly at different time after Mg(2+)-free treatment in neurons cultured for different days, but the increase was not significant (P > 0.05). (4) Metabolic rate decreased at 6 h after Mg(2+)-free treatment (P < 0.05) in neurons cultured for 6 d, and was 86.4% of that of the control; while the rate at 24 h in neurons cultured for 12 d and 17 d also decreased (P < 0.05), being 78.7% and 70.9%, respectively, of that of the control. CONCLUSIONS: These findings demonstrated that the injury occurred on cultured cortical neurons caused by magnesium-free-treatment-induced recurrent epileptiform discharges was mainly functional and relatively mature neurons displayed more severe and much later mitochondrial function impairment than immature neurons.

Animals↗
PubMed2002

[Determination of sildenafil in medicines for erectile dysfunction by capillary electrophoresis].

A method has been developed for the determination of sildenafil in the medicines for erectile dysfunction by capillary electrophoresis. The samples were analyzed with 60 mmol/L NaH2PO4(pH 5.0) running buffer at 35 degrees C capillary temperature and 30 kV voltage. A linear calibration was obtained from 0.07 g/L to 1.05 g/L of sildenafil (r = 0.9985) with the RSD of 4.7% for peak area, and the average recovery was 97.4%. The results were compared with those of HPLC, showing that the method is precise, simple and cost-effective, and can be used as a complementary method to HPLC.

Calibration↗