Biomedical subjects

Mei Li

Publications and source records attributed to Mei Li.

At least 37 records · Page 2Linked to original sources

PubMed2006

Removal of disperse blue 2BLN from aqueous solution by combination of ultrasound and exfoliated graphite.

This paper reports an efficient and convenient removal of disperse blue 2BLN from aqueous solution by the combination of ultrasound and exfoliated graphite. The various affecting factors were studied. The removal ratio of disperse blue 2BLN is 96.9% for the initial concentration of 200 mg/L using 600 mg/L exfoliated graphite (exfoliation volume of 300 mL/g) at 45 degrees C within 120 min under ultrasound. The combination method was more effective than sonolysis or exfoliated graphite treatment individually.

Absorption↗

PubMed2006

Synthesis and characterization of cerium phosphate nanowires in microemulsion reaction media.

Synthesis of CePO4 in water-in-oil microemulsions produces crystalline nanowires with uniform thickness (mean width = 3.7 nm) and straight or branched morphologies. The nanowires develop within a period of 1 month by surfactant-mediated slow crystallization from amorphous primary filaments with highly convoluted morphology. Electron microscopy and dynamic light scattering studies suggest that CePO4 crystallization occurs within the confined reaction spaces of preformed Ce(III)-containing rod-shaped micelles, rather than by mesophase aggregation and transformation of primary surfactant-coated nanoparticles.

Cerium↗

PubMed2006

CXCL12/CXCR4 expression in trophoblasts takes part in materno-fetal immune tolerance and vascular remodeling.

In this study, we investigated the expression of CXCL12 (SDF-1)/CXCR4 in trophoblasts and the role they play in the gestation. Immunochemistry was used to detect the expression of CXCR4 and CXCL12 in human villi and placenta. Highly purified extra-villous trophoblasts (EVTs) ere detected for CXCR4 and CXCL12 in vitro by immunocytochemistry. The chemotaxis of CXCL12 was tested in transwell and the chemotactic activity was quantitatively examined. It was suggested that both CXCR4 and CXCL12 were expressed in trophoblasts and were decreased with the gestation time P < 0.05). In a certain coverage, CXCL12 exhibited chemotactic activity which was positively correlated with its concentration [(r) = 0.68, P < 0.01], the maximum chemotactic index (CI) was 1.62 +/- 0.12. Our results suggest that interaction between CXCR4 and CXCL12 is involved in materno-fetal immunological tolerance in all three trimesters of gestation and contributes to the invasion of EVTs during pregnancy.

Adult↗

PubMed2006

Bioactive isomalabaricane triterpenoids from Rhabdastrella globostellata that stabilize the binding of DNA polymerase beta to DNA.

Four isomalabaricane triterpenoids were isolated from an extract of the sponge Rhabdastrella globostellata that was active in an assay measuring stabilization of the binding of DNA with DNA polymerase beta. The known compounds stelliferin riboside (1) and 3-epi-29-acetoxystelliferin E (2) were shown to induce 29% and 23% binding, respectively, at 28 microg/mL, while the new compound stellettin J (3) induced 5% binding at 28 microg/mL. The new compound stellettin K (4) had no activity in the binding assay. The compounds were characterized by spectroscopic methods. These compounds displayed varying levels of activity toward the A2780 ovarian cancer cell line, revealing structure-based effects on both the level of cytotoxicity and DNA-polymerase beta binding. This is the first report of natural products with the ability to promote stabilization of the DNA-polymerase beta covalent binary complex.

Animals↗

PubMed2006

Chronic long-standing headache due to neurocysticercosis.

A 35-year-old Chinese woman presented with a 26-year history of persistent headache, relieved only by diuretics. Characteristic CT findings, peripheral eosinophilia, lymphocytic CSF pleocytosis, elevated CSF IgG, positive oligoclonal bands, antibody-positive ELISA, and Western blot results with Taenia solium antigen, and a favorable response to albendazole led to the diagnosis of neurocysticercosis.

Adult↗

PubMed2006

Study of the interaction of indirubin with bovine serum albumin.

This study examined the interaction of indirubin with bovine serum albumin (BSA) at three temperatures (286, 297, 308 K) at pH 7.40. In the presence of indirubin, the drug-BSA binding mode, binding constant and the protein structure changes in aqueous solution were determined by fluorescence quenching methods including Fourier transform infrared (FT-IR) spectroscopy and UV-Vis spectroscopy. The FT-IR change indicates that indirubin binds to BSA. The change in protein secondary structure accompanying ligand binding has been proved by fluorescence spectra data. The thermodynamic parameters, the enthalpy change (DeltaH), and the entropy change (DeltaS) calculated by the van't Hoff equation possess small negative (-2.744 kJ.mol(-1)) and positive values (112.756 J.mol(-1).K(-1)), respectively, which indicated that hydrophobic interactions play the main role in the binding of indirubin to BSA. Furthermore, the displacement experiment shows that indirubin can bind to the subdomain IIA and the distance between the tryptophan residues in BSA and indirubin bound to site I was estimated to be 2.24 nm according to Föster's equation on the basis of fluorescence energy transfer.

Animals↗

PubMed2006

[Construction of a plant effective expression vector containing the gene of hepatitis B virus surface antigen].

OBJECTIVE: To construct a plant effective expression vector driven by a fruit specific promoter for the expression of hepatitis B virus surface antigen (HBsAg), to further improve the expression of exogenous gene in plant, and to prepare for the development of an effective anti-hepatitis vaccine. METHODS: Tomato fruit-specific promoters' gene 2A12 and E8 were respectively introduced to pBPFOmega7 to form pB2A12 and pBE8. The DNA fragment containing HBsAg-s gene from plasmid YEP-HBs was inserted respectively into pB2A12 and pBE8 to form pB2A12-HBs and pBE8-HBs. The fragment containing "p35S+2A12+Omega+HBsAg-s+Tnos" of the pB2A12-HBs was sub-cloned into plasmid pCAMBIA1301 to yield the reconstructed plant binary expression plasmid pCAM2A12-HBs, and the fragment containing "p35S+E8+Omega+HBsAg-s+Tnos" of the pBE8-HBs was sub-cloned into plasmid pCAMBIA1301 to yield the plasmid pCAME8-HBs. The inserted gene HBsAg and fruit-specific promoters in the reconstructed plant binary expression vectors were confirmed by sequencing. Then, pCAM2A12-HBs and pCAME8-HBs were directly introduced into Agrobacterium tumefaciens strain EHA105. RESULTS: Digestion with restriction enzymes proved that all recombinant vectors had the inserts with expected length of the target fragments, and the sequencing results were confirmed correct. CONCLUSION: In this study, plant expression vector containing HBsAg gene driven by fruit specific promoter and CaMV35s promoter was successfully constructed.

Cloning, Molecular↗

PubMed2006

[Removal of coliphages by wastewater treatment processes].

The concentrations of somatic coliphages (SC) and F-specific RNA bacteriophages in effluent of three wastewater treatment plants in Beijing city were detected. Somatic coliphages and F-RNA bacteriophages in source wastewater were 6.25 x 10(3) - 1.34 x 10(4) PFU x mL(-1) and 2.4 x 10 - 2.4 x 10(3) PFU x mL(-1) respectively, and the corresponding average removal rates were 72.45% - 99.89 % and 57.84% - 93.06% by the wastewater processes, and which were lower than that of faecal coliforms. Biological aerated stage appeared to be the most efficient step in reducing the numbers of phages in wastewater, but not obviously in sand filter. The result of predicted concentrations of enteroviruses according to concentrations of F-RNA bacteriophages in water show that there are 0.65 - 15.8 PFU x L(-1) of the enteroviruses in final effluent.

Coliphages↗

PubMed2006

[Skeletal biomechanical properties improvement in ovariectomized osteoporotic rats of teriparatide was retarded by alendronate].

OBJECTIVE: To implore the effects of teriparatide (PTH) and alendronate (Alen) on skeletal biomechanical properties of ovariectomized (OVX) osteoporotic rats. METHODS: 70 female Wistar rats of 6 months were randomly divided into 7 groups: (1) Baseline: sacrificed at baseline; (2) OVXb: sacrificed in 6 weeks after OVX; (3) Sham operation; (4) OVXe: sacrificed 14 weeks after OVX; (5) PTH: 40 microg.kg(-1).d(-1); (6) Alen: 100 microg.kg(-1).d(-1); (7) A + P: PTH 40 microg.kg(-1).d(-1) and Alen 100 microg.kg(-1).d(-1). In group (5)-(7), different medicines were injected 5 times per week from 6th to 14th week after OVX. The cancellous biomechanical properties were measured with indentation test and the cortical properties were investigated with three-point bending test. RESULTS: (1) The can load and can stiff of distal femur of OVXb were significantly lower than those of baseline (P < 0.01). It is indicated that osteoporotic rat models with impaired bone strength were established. (2) The can load and can stiff of distal femur of PTH [(36.3 +/- 9.2) N, (160.7 +/- 48.0) N/mm(2)], Alen [(42.7 +/- 13.0) N, (122.9 +/- 35.6) N/mm(2)] and A + P [(44.3 +/- 18.2) N, (105.2 +/- 58.4) N/mm(2)] groups were all higher than those of OVXe [(19.5 +/- 8.5) N, (83.2 +/- 37.7) N/mm(2), P < 0.001 or P < 0.01]. In femoral shaft, maximal load and elastic load in PTH, Alen and A + P groups were higher than those of OVXe (P < 0.001, P < 0.01 or P < 0.05). (3) Can stiff in distal femur was higher in PTH than that in Alen and A + P groups (P < 0.05). Elastic load, maximal load and energy absorption in femoral shaft were higher in PTH and A + P groups than those in Alen group (P < 0.05), and maximal stress was higher in PTH than that in A + P and Alen group (P < 0.05). CONCLUSION: PTH and Alen were effective in improving the skeletal mechanical properties of OVX rats, but improvement in Alen and A + P was not so good as that in PTH group. It is indicated that anabolic effects of PTH was retarded by Alen's significant inhibition of bone turnover, therefore, PTH and Alen should not be utilized simultaneously.

Alendronate↗

PubMed2006

[Oocyte activation with calcium ionophore A23187 and puromycin on human oocytes that fail to fertilize after intracytoplasmic sperm injection].

OBJECTIVE: To investigate the effect of assisted oocyte activation with calcium ionophore A23187 and puromycin on human oocytes that fail to fertilize after intracytoplasmic sperm injection (ICSI). METHODS: All 113 discarded oocytes that showed no evidence of fertilization at 16 - 18 hours after in vitro maturation (IVM)-ICSI cycles and conventional ICSI were assigned to four groups according to the time after ICSI: IVM-ICSI 22-hour group (n = 33), IVM-ICSI 44-hour group (n = 18), ICSI 44-hour group (n = 37) and ICSI 68-hour group (n = 25). All unfertilized oocytes were exposed to calcium ionophore A23187 (5 micromol/L) for 5 minutes and subsequently incubated with puromycin (10 microg/ml) for 4 hours. After incubation, the oocytes were cultured in vitro for 3 - 5 days. The activation rate, proportion of oocytes that showed pronucleus formation and cleavage rate were calculated after activation. Sex chromosomal analysis was performed by dual color fluorescence in situ hybridization (FISH) on the embryos that displayed two pronuclei and a second polar body. RESULTS: The combination of calcium ionophore A23187 with puromycin could activate the unfertilized oocytes 22 - 68 hours after ICSI. Best results were achieved in IVM-ICSI 22-hour group, which elicited 88% (29/33) of activation rate, 62% (18/29) of cleavage rate and 28% (5/18) of 4-cell embryos. One embryo in this group developed to the morular stage. The activation rate and developmental potential of the activated embryos in IVM-ICSI 44-hour group, ICSI 44-hour group and ICSI 68-hour group decreased. FISH analysis showed 4 embryos with XX and 9 embryos with XY in 16 embryos. CONCLUSIONS: The combination of calcium ionophore A23187 with puromycin could effectively activate unfertilized oocytes 22 - 68 hours after ICSI. The cultured time of unfertilized oocytes after ICSI affects activation efficiency and developmental potential of the activated embryos. The activated zygotes that display two pronuclei and a second polar body can develop normally.

Calcimycin↗

PubMed2006

[The application of multi-slice computed tomograph in diagnosis and operation of hypopharyngeal carcinoma].

OBJECTIVE: To evaluate the clinical application of multi slice CT(MSCT) in hypopharyngeal carcinoma and serve otolaryngologist to institute proper operation. METHOD: Forty-five patients with hypopharyngeal carcinoma scanned by MSCT were studied and confirmed by operation and pathologic examination. The operation material were retrospectively analyzed. All the cases were used for the enhancement scanning, whose scope was from hard palate to cervical segments of esophagus. RESULT: Of 45 cases, 34 cases derived from piriform fossa, 7 cases were from the postcricoid region and 4 cases were in the posterior wall of hypopharynx. The tumor showed isodense or mixed density and slightly enhancement, piriform fossa became narrow or disappeared, retropharyngeal soft tissue thickened, laryngeal cartilage and esophageal ostium were invaded and lymph nodes of neck became metastasis. The tumor pushed the annular and arytenoids cartilage displacement anteriorly; the thyroid arytenoidal gap and cricothyroid joint were widened. The operation plan that was made according as MSCT was almost agreed with actual operation. The consistent rate is 91.1% (41/45). CONCLUSION: MSCT examination can accurately diagnose and exhibit the extension of the tumors and detect metastasis to lymph nodes, and provide reliable basis for surgery therapy.

Adult↗

PubMed2006

[Genotypic analysis of familial dilated vestibular aqueduct syndrome].

OBJECTIVE: To analyze clinical manifestation of patients from two families with dilated vestibular aqueduct syndrome (DVAS). Their genotypic patterns were discriminated with the genetic testing methods for PDS gene. METHOD: The twin sisters from pedigree and the brother and sister from pedigree 2 all suffered from sensorineural hearing loss. All patients from these two families were confirmed to have enlarged vestibular aqueduct by temporal bone CT scan. Exon 7+8 and their flanking area sequences were analyzed by direct sequencing. All other exons and their flanking sequences were screened by DHPLC. The amplicons of exons which showed abnormal DHPLC wave pattern were further sequenced. RESULT: The parents of two families are non-consanguineous, hearing normal couples with no other family members with hearing loss. Both families have two offspring with DVAS. The clinical features of all patients were progressive hearing loss, good communication ability but with thickness pronunciation. Both twin sisters from pedigree are homozygous for the splice site mutation (IVS 7-2 A-G) affecting the 3 splice site consensus sequence of intron 7. The brother and sister of pedigree 2 are compound heterozygotes for 1199 ins T mutation and a missense mutation (1229 C-T). CONCLUSION: Familial DVLS is typical hereditary disease. The patients with DVLS have similar clinical manifestation and the same genotypic changes in PDS.

Adult↗

PubMed2006

[Orientation taping magnetic granules at auricular points and Neiguan (PC 6) for prevention and treatment of 102 cases of motion sickness].

OBJECTIVE: To observe therapeutic effect of orientation taping magnetic granules at auricular points and Neiguan (PC 6) on motion sickness. METHODS: All 200 cases of motion sickness were divided into a treatment group (n = 102) and a control group (n = 98). The treatment group were treated with orientation taping magnetic granules at auricular points and Neiguan (PC 6), and the control group with oral administration of theohydramine. RESULTS: There was a significant difference between the two groups in the total effective rate (P < 0.05), and clinical symptoms disappeared more rapidly in the treatment group as compared with the control group (P < 0.05). The therapeutic effect in the mild and moderate patients of the treatment group was better than that of the control group, and there was no significant difference in the therapeutic effect for the severe patients between the two groups. In the treatment group, the therapeutic effect of the mild patient was the best, the moderate patient was next and the severe patient was the worst, with a very significant difference (P < 0.005). CONCLUSION: Orientation Taping magnetic granules at auricular points and Neiguan (PC 6) has an obvious therapeutic effect on motion sickness, with less adverse reactions.

Acupuncture Points↗

PubMed2006

[Comparison of the outcome of intracytoplasmic single sperm injection between two motile sperm separation methods].

OBJECTIVE: To evaluate the efficiency of density gradient and improved swim-up methods for motile sperm isolation from fresh semen samples in intracytoplasmic sperm injection and embryo transfer (ICSI-ET) program, thus guiding the clinical application. METHODS: The fertilization rate, cleavage rate, high-quality embryo rate, clinical pregnancy rate, sperm abnormal rate and recovery rate of 42 cycles were studied prospectively. The cycles were divided into two groups with respect to the motile sperm isolation methods. RESULTS: No obvious difference was found in the fertilization rate, cleavage rate, high-quality embryo rate and clinical pregnancy rate between the two methods. The abnormal sperm rate induced by the improved swim-up method was significantly higher than that of the density gradient method (P < 0.01). For severe oligozoospermia, the recovery rate of motile sperm with density gradient was higher than that of improved swim-up (P < 0.01). CONCLUSION: In the ICSI-ET, there is no obvious difference in clinical pregnancy outcome between the two methods. The method of improved swim-up can be used for all patients but those with severe oligozoospermia.

Adult↗

PubMed2006

[Effect of nitrite on aerobic phosphate uptake by phosphate accumulating organisms].

Effect of nitrite at various concentration levels on aerobic phosphate uptake was investigated through a series of batch experiments. Furthermore, the effect of nitrite accumulated in the process of nitrification on aerobic phosphate uptake was studied in saline wastewater treatment. The results show that NO2(-) -N concentration of 4 mg/L inhibits aerobic phosphate uptake by phosphate uptake by phosphate accumulating organisms (PAO) and phosphate uptake rate decreases 8%. Exposure to higher nitrite concentration levels inhibits aerobic phosphate uptake severely. At NO2(-) -N concentration of 15 mg/L, phosphate uptake rate decreases 61%. The toxic effect of nitrite is presumed to be linked with free nitrous acid (FNA). Significant inhibition on aerobic phosphate uptake appeared at 0.000 2 mg/L of FNA concentration. The inhibiting effect of nitrite is found to occur only when nitrite is present. The ability of accumulating phosphate resumes afternitrite is no longer present. During the process of nitrification of nitrification of saline wastewater, the inhibition of nitrite on aerobic phosphate uptake is slight at the initial 1 - 2 h due to low nitrite accumulation. With the build-up of NO2(-) -N(up to about 8 to 9 mg/L), the inhibiting effect of nitrite increases gradually. It is found that higher ammonium concentration causes lower pH value and higher FNA concentration, which could decrease the amount of phosphate uptake.

Bacteria, Aerobic↗

PubMed2006

[Profiles of sediment porewater nutrient concentrations on tidal flat of turbidity maximum zone in Changjiang (Yangtze River) estuary].

Profiles of nutrients (i.e., NH4+, NO2-, NO3-, PO4(3-), and SiO3(2-)) in porewater of sediment were investigated monthly in the intertidal flat of Chongming Dongtan in Changjiang (Yangtze River) estuary during March 2005 to February 2006. The results indicate that concentrations of NH4+ and SiO3(2-) in porewater are always in the range of 200 micromol/L to 500 micromol/L and show different patterns of distribution profile among high, middle, and low marshes. Compared to high and middle marsh, low marsh, without vegetation coverage and of coarser grain size, generally contains higher NH4+ and lower SiO3(21) concentrations. SiO3(2-) concentrations are predominantly determined by seasonal temperature change, but variations of NH4+ are more complicated and prone to exhibit lower values in spring and summer when the vegetation above show relatively high growth rate. Concentrations of NO2- + NO3- and PO4(3-) in porewater are commonly much lower than NH4+ and SiO3(2-) by 2 to 3 orders of magnitude, however, due to factors such as bioturbation, the concentrations in top sediment may be higher than 10 micromol/L. The relatively high NO3- concentration in top sediment,together with the rapid transfer from oxygenic to anoxic environment, make it possible that significant denitrification happens, which may draw its remarkable influence on the biogeochemical cycles of nutrient elements in the land-sea interaction area in Changjiang (Yangtze River) estuary.

China↗

PubMed2006

[Application of SELDI-TOF MS technology analyzing serum protein profiling for distinguishing laryngeal carcinoma from ordinary people].

OBJECTIVE: To analyze the spectrometric serum protein profiling of laryngeal carcinoma and healthy controls by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS), to establish serum marker pattern for the diagnosis of laryngeal carcinoma. METHOD: The serum samples of 46 cases of laryngeal carcinoma, 51 cases of healthy controls on WCX2 proteinchip, were collected. the spectrometric protein profiling was defected by SELDI-TOF-MS, the data were analyzed by Biomarker Patterns Software provided by Ciphergen Corp. A primary diagnosis model of laryngeal carcinoma was set up. This model was further evaluated by blind test with other l2 cases patients and 13 cases healthy controls. RESULT: Seventy-six protein peaks were detected at the molecular range of 2000-20000 Da., among which 27 ones were significantly different between laryngeal carcinoma and controls( P < 0.05). A diagnostic pattern consisting of 3 protein peaks was established with of accuracy 88.7% (86/97), sensitivity 87% (40/46), specificity 90.2% (46/51), Blind test generated a sensitivity of 83.3% (10/12)and specificity of 84.6% (11/13) respectively. CONCLUSION: It is successful to develop and evaluate the different spectrometric protein profiling patterns of laryngeal carcinoma and healthy control by SELDI-TOF-MS. This affords possibly a new method to early diagnosis of laryngeal carcinoma.

Adult↗

PubMed2005

Two different O-polysaccharides from Escherichia coli O86 are produced by different polymerization of the same O-repeating unit.

The structure of a new O-polysaccharide from Escherichia coli O86:K62:B7 was determined using NMR and methylation analysis. The structure is as follows: [carbohydrate: see text]. Comparison with the previously published structure from E. coli O86:K2:H2 revealed that the O-polysaccharides from these two E. coli O86 serotypes share the same branched pentasaccharide repeating unit. However, they differ in the anomeric configuration of the linkage, the linkage position, and the identity of the residue through which polymerization occurs. The immunochemical activity of these two forms of LPS toward anti-B antibody was studied and compared. The results showed that LPS from E. coli O86:K2:H2 strain possesses higher blood group B reactivity. The immunoreactivity difference was explained by modeling of the O-repeating unit tetrasaccharide fragments. This finding provides a good system for the further study of O-polysaccharide biosynthesis especially the repeating unit polymerization mechanism.

ABO Blood-Group System↗