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Biomedical subjects

Jun Li

Publications and source records attributed to Jun Li.

At least 469 records · Page 26Linked to original sources
PubMed2004

[Association studies of G352A polymorphism of dopamine transporter gene in Han Chinese attention deficit hyperactivity disorder patients].

OBJECTIVE: To investigate association of the new polymorphism G352A in the dopamine transporter gene (DAT1) exon 15 with attention deficit hyperactivity disorder (ADHD) in Han Chinese children. METHODS: The new mutant polymorphism G352A in the dopamine transporter gene (DAT1) exon 15 was found by the fluorescently-labeled dye-terminators assay. The study samples were comprised of 337 ADHD children, 207 unrelated controls and 201 integrated ADHD trios (included proband and biological parents). Associations of polymorphisms with ADHD and its subtypes were examined by: (i) comparing cases and controls; and (ii) using family-based association study in transmission-disequilibrium test (TDT). RESULTS: The allele frequencies at the DAT1 G352A locus in the control samples were 79.5% for 352G and 20.5% for 352A respectively. Association studies revealed no association between G352A in exon 15 of DAT1 and ADHD. But after a stratification by gender, there was possible association between G352A and ADHD girls: the 352G allele had a tendency to be preferentially transmitted to ADHD girls. CONCLUSION: There is no association between G352A, the new polymorphism, in exon 15 of DAT1 and ADHD. The 352G allele has a tendency to be preferentially transmitted to ADHD girls, but the findings require replication before drawing a definitive conclusion.

Adolescent↗
PubMed2004

[One new phenylethanoid glycoside from Corallodiscus flabellata].

AIM: To study the antivirus chemical constituents of Corallodiscus flabellata. METHODS: The compounds were isolated with macroporous absorption resin, Diaion HP-20, Sephadex LH-20, silica gel column chromatography and identified on the basis of their physio-chemical and spectral data. RESULTS: Four compounds were obtained and identified as 1'-O-beta-D-(3,4-dihydroxyphenyl)-ethyl-6'-O-vanilloylglucopyranoside (1); 1'-O-beta-(4-hydroxyphenyl)-ethyl-beta-D-apiofuranosyl-(1-->2')-glucopyranoside (2); 4-hydroxyphenethyl alcohol (3); bis (2-hydroxyethyl) ether (4). CONCLUSION: Compound 1 is a new compound, compounds 2-4 were isolated from Corallodiscus flabellata for the first time.

Magnoliopsida↗
PubMed2004

[The significance of beta-catenin and matrix metalloproteinase-7 expression in colorectal adenoma and carcinoma].

OBJECTIVE: To investigate the relationship between beta-catenin and matrix metalloproteinase-7 (MMP-7) expression and development/biologic behavior of human colorectal cancer. METHODS: Immunohistochemical study for beta-catenin and MMP-7 was carried out on colorectal adenoma-carcinoma tissue microarrays and results analyzed. RESULTS: The nuclear beta-catenin expression rate was 35.9% in adenoma with malignant transformation, significantly higher than that in adenoma (16.7%) and carcinoma (19.7%) (both P < 0.05). The cytoplasmic and nuclear beta-catenin expression rate in adenoma with severe dysplasia was significantly higher than that in adenoma with mild dysplasia (both P < 0.05). The nuclear beta-catenin expression rate in adenocarcinomas of the ulcerative type, with lymph node metastasis and in the late tumor stages were all significantly higher than that in adenocarcinomas of the polypoid type, with negative lymph node and in the early tumor stages (P < 0.05 or P < 0.01). The MMP-7 expression rate in adenocarcinoma (69.2%) was significantly higher than that in normal colorectal mucosa (15.0%), adenoma (35.0%) and adenoma with malignant transformation (46.2%, P < 0.05 or P < 0.01). The MMP-7 expression rate in ulcerative type adenocarcinoma with lymph node metastasis and in late tumor stages was significantly higher than that in polypoid type adenocarcinoma with negative lymph node and in early tumor stages (all P < 0.05). The cytoplasmic and nuclear beta-catenin expression was thus in positive correlation with the expression of MMP-7 (both P < 0.01). CONCLUSIONS: The cytoplasmic and nuclear beta-catenin expression, probably an early event, was related to the development of colorectal cancer. beta-catenin may enhance the degradative function of the target gene MMP-7 through nuclear translocation and may further facilitate local invasion and metastasis by the colorectal cancer cells.

Adenocarcinoma↗
PubMed2004

[Comparative study on lipogenic and lipolytic gene expression in intramuscular fat tissue between growing Erhualian and large white pigs].

To investigate the mechanism of difference in intramuscular fat deposition between Erhualian and Large White pigs,single tube relative-quantitative RT-PCR method was used to investigate the development patterns of lipogenic (ACX, LPL, ME) and lipolytic (HSL) gene expression with 18S internal standard control. Sixteen Large White boars and twenty Erhualian boars were selected and raised according to normal nutrition standard respectively. The animals were selected randomly and slaughtered at 15 kg, 40 kg, 60 kg and 90 kg for Large White pigs and at 18 kg, 40 kg, 60 kg, 80 kg and 90 kg for Erhualian pigs respectively; with four animals of each breed at each time. The supraspinatus and semimembranosus muscles were removed for total RNA extraction and longisimus dorsi muscle for intramuscular fat (IMF) analysis using ether extract method. The results showed: (1) The property of IMF between Erhualian and Large White boars was similar during early growing period (before 40 kg) (P > 0.05) ,thereafter, IMF level of Erhualian boars increased dramatically to 4% at 60 kg and over 5% at 90 kg while Large White boars kept steadily at about 2% (P < 0.05); (2) The pattern of lipogenic and lypolytic gene expression was similar between semimembranosus and supraspinatus muscle in each breed; (3) The tendency for LPL and ME mRNA expression coincided with that of IMF development among 20 approximately 60 kg in Erhualian pigs. The results suggest that the development of IMF between 20 kg and 60 kg in Erhualian pigs may play a meaningful role in deposition of IMF,and that the expression of ME and LPL mRNA may contribute to fast sediment of IMF in Erhualian pigs.

Adipose Tissue↗
PubMed2004

[Soil respiration characteristics in winter wheat field in North China Plain].

Experiments were conducted at the Yucheng Comprehensive Experimental Station of the Chinese Academy of Sciences during 2002-2003 to investigate the respiration of a pulverous sandstone soil under cultivation of winter wheat over a growth season. The effluent CO2 was collected and analyzed by the static-chamber/gas chromatography (GC) method at a frequency of once a week in spring and autumn, once two weeks in winter, twice a week for straw manure treatment, once a week for no straw manure treatment and nitrogen fertilization treatment in summer. The results indicated that diurnal variation of soil respiration rate showed a single peak in typical winter wheat farmlands in the North China Plain, and reached the highest at about 13 o'clock, and the lowest at about 4 o'clock in the early morning. In winter wheat growth season, the soil respiration rate was 31.23-606.85 mg x m(-2) x h(-1) under straw manure, 28.99-549.66 x m(-2) x h(-1) under no straw manure, 10.46-590.86 mg x m(-2) x h(-1) in N0, 16.11-349.88 mg x m(-2) x h(-1) in N100, 12.25-415.00 mg x m(-2) x h(-1) in N200, and 23.01-410.58 mg x m(-2) x h(-1) in N300, showing a similar seasonal variation tendency with soil temperature. Among all treatments, the straw manure had the most distinct soil respiration, though the soil respiration also increased slightly with increasing nitrogen fertilization. Soil respiration increased exponentially with increasing soil temperature, and the correlation of soil temperature at the depth of 5 cm was the best. This relationship was usually described with the Q10 model, which represented the sensitivity of soil respiration to temperature. Q10 was not a fixed value, which varied with the depth at which the temperature was measured and the depth of the active soil layer and soil temperature. At same time, the Q10 value decreased with increasing soil temperature. Soil water content was another important factor affecting soil respiration rate, but in this region, the relationship between soil respiration and soil moisture was poor, and no distinct rules were shown. The average net photosynthesis rate of winter wheat had a close relation with soil respiration rate. The differences between them showed that the photosynthetic uptake of CO2 was beyond emission of soil respiration during the period from return green to mature, and the winter wheat farmland was a sink of CO2.

Carbon Dioxide↗
PubMed2004

[Distribution and prognostic significance of microvessel density in supraglottic laryngeal squamous cell carcinomas].

OBJECTIVE: To study the distribution and prognostic significance of microvessel density (MVD) in supraglottic laryngeal squamous cell carcinomas (SGLSCC). METHOD: The patients of 59 primary SGLSCC received surgical treatment and 19 vocal cord polyps (VCP) were studied with CD31 immunohistochemical staining using Two Steps System Kits. RESULT: There were many microvessels in the stroma of SGLSCC compared with the connective-tissue under epithelium of VCP. Kendall's ranked correlation analysis indicated that only MVD and nodal status had significant correlation (P<0.01) in all clinicopathological parameters. Both between N0 and N+ and between SGLSCC and VCP MVD were significantly different (P<0.01) by independent-samples t test. Kaplan-Meier survival analysis showed significant relationship existed in MVD and cumulative survival rate of SGLSCC patients (P<0.01). CONCLUSION: This study further proves that angiogenesis plays important roles in tumorigenesis, invasiveness and metastasis. MVD could predict the lymph node metastasis and are significantly associated with the prognosis of SGLSCC patients.

Adult↗
PubMed2004

[Function of nanoparticles in transdermal and transmucosal drug delivery systems].

Nanoparticles had received much attention in the development of new kind of pharmaceutical formation because of the special nano-effectivity. Recently, some studies discovered the special functions of the nanoparticles in transdermal and transmucosal drug delivery systems. Even though the acting mechanism of the nanoparticles in these drug delivery systems are not known, these discoveries of the special function of the nanoparticles provide new developing prospect to the drug delivery systems. This paper mainly reviews the present studying results about the nanoparticles used in the transdermal and transmucosal drug delivery systems, including the lipid nanopaticles, natural polymer and the synthesized polymer nanoparticles.

Administration, Cutaneous↗
PubMed2004

[Electron spectra of chemical assembly mesoporous MCM-41 with transition metal complexes].

In the paper the complexes of metal cobalt(III), manganese(III), iron(III) and copper(II) with Schiff-base N,N-ethylenebis(salicylideneaminnato) have been synthesized and characterized. The nanosized porous material MCM-41 has been functionalized by the modification of the internal pore surface with gamma-aminopropyl and was assembled by the modification groups with metal complex of Schiff-base. These metal complexes and functionalized nanosized porous materials were charcterized by XRD, IR and UV-Vis. It is indicated by spectral analysis that the synthesized nanosized porous materials have been confirmed to be MCM-41 with hexagon bores, and the gamma-aminopropyls have been bonded on their internal pore surface. And the complexes of metal cobalt(III), manganese(III), iron(III) and copper(II) with Schiff-base N,N-ethylenebis(salicylideneaminnato) were assembled into MCM-41. The IR spectra of these samples show that there were characteristic absorptions of the amino and the Schiff base groups, and the absorption of amino shifted to longer wavelength.

Cobalt↗
PubMed2004

[Preparation and spectra of the complexes of the first series transition metals with diphenic acid].

The ligand diphenic acid has been synthesized and the corresponding complexes of transition metal Co, Ni and Mn with diphenic acid have been prepared and characterized by the elementary analysis, IR spectra and ultraviolet-visible spectra. The results of IR show that the vas and vs of -CO2- in the complexes are lower than those of ligand diphenic acid, which can be explained by the coordinating between metal and ligand. In addition, compared with the complex IR spectra, the IR spectra of ligand became complicated due to the ligand polymerization through hydrogen bond. The UV-Vis spectra show that the ligand has three absorption peaks at 288, 273 and 270 nm, respectively, and these are slightly shifted in the complexes. Because the metal d-d absorption is weak, only in Co(C14H8O4) x 2H2O there is a d-d absorption at 537 nm.

Biphenyl Compounds↗
PubMed2004

[Cu and Pb contents in Dichondra repens leaf and their effects on its physiological indexes].

This paper analyzed the contents of Cu and Pb in Dichondra repens grown on Cu and Pb contaminated soil to determine if this plant is a hyperaccumulator of two elements. The results indicated that total content of Cu (44.8 g x kg(-1)) in the plant was higher than that of Pb (25.59 g x kg(-1)), and the contents of two elements were higher in roots and stems than in leaves and increased with increasing soil contamination. The accumulation coefficient of Cu (0.784) was higher than that of Pb (0.465). With the increasing concentrations of two heavy metals, the chlorophyll a content and chlorophyll a/b ratio in leaf decreased, the SOD activity increased to the peak and decreased subsequently, while the POD activity always maintained an increasing trend. The membrane permeability of cell was not significantly varied.

Copper↗
PubMed2004

The role of innate immune cells in the response of heat-treated Mycobacterium tuberculosis (M.tb) antigens stimulating PBMCs.

The proliferation response of gammadelta T cells to the antigen from heat-treated Mycobacterium tuberculosis H37Ra (M.tb Ag) was used as a good model in gammadeltaT cell research. From preliminary research it is found that activated NK cells positively elevated gammadeltaT cells proliferation after simulating PBMCs with M.tb Ag. To investigate different behaviors of NK cells, gammadeltaNKT cells, gammadeltaT cells and relationships between these cell subsets, activation and proliferation of different cell subsets of PBMCs in response to M.tb Ag were analyzed. We demonstrated that NK cells, gammadeltaNKT cells and gammadeltaT cells could be activated after stimulation with M.tb Ag. gammadeltaNKT cells and gammadelta T cells proliferated while the number of NK cells decreased after 11 day-simulation with M.tb Ag. Meanwhile, at the early time of stimulation the cytotoxicity of PBMCs was enhanced.

Antigens, Bacterial↗
PubMed2004

System optimization for the development of ultrasensitive electronic biosensors using carbon nanotube nanoelectrode arrays.

Vertically aligned multi-walled carbon nanotubes (MWCNTs) have been reported in fabricating nanoelectrode arrays. Further studies on optimizing this system for the development of ultrasensitive DNA sensors are reported here. The mechanical stability of the as-grown MWCNT array can be improved by polymer coating or SiO2 encapsulation. The latter method provides excellent electronic and ionic insulation to the sidewall of MWCNTs and the underlying metal layer, which is investigated with electrochemical impedance spectroscopy. The insulation ensures well-defined nanoelectrode behavior. A method is developed for selectively functionalizing biomolecules at the open end of MWCNTs while keeping the SiO2 surface passivated, using the unique graphitic chemistry. An ultrahigh sensitivity approaching the limit of fluorescence techniques is obtained with this system for DNA detection.

Base Sequence↗
PubMed2003

[Association between tryptophan hydroxylase gene polymorphisms and attention deficit hyperactivity disorder with or without learning disorder].

OBJECTIVE: To investigate the relationship between two tryptophan hydroxylasec (TPH) gene polymorphisms, A218C and A-6526G polymorphisms, and attention deficit hyperactivity disorder (ADHD) with or without learning disorder (LD). METHODS: Blood samples were taken from 132 trios with probands of ADHD with LD and 221 trios with probands of ADHD without LD. DNA was extracted and PCR was performed to amplify the fragments of A218C amd A-6526G polymorphisms. NheI and MboI were used to detect different alleles of the two polymorphisms separately. transmission disequilibriumtest (TDT) and haplotype analysis were used to test the association of the two polymorphisms of TPH gene and ADHD with or without LD. RESULTS: Haplotype block composed by A218C and A-6526G polymorphisms was related to ADHD with LD (chi(2) = 9.362, df = 3, P = 0.025). The haplotype of 218A/-6526G was significantly untransmitted to the probands with ADHD with LD (chi(2) = 9.252, df = 1, P = 0.002). CONCLUSION: TPH gene and the haplotype of 218A/-6526G may be related to ADHD with LD.

Adolescent↗
PubMed2003

A novel recombinant antigen for immunodiagnosis of human cystic echinococcosis.

A pool of serum samples from mice infected with oncospheres (eggs) of Echinococcus granulosus was used to screen a cDNA library constructed with RNA extracted from protoscolex larvae from sheep hydatid cysts. One immunoreactive clone, designated EpC1, was shown to encode a protein of 76 residues. The complementary DNA (cDNA) fragment was subcloned into an expression vector, pET-41b(+), and the resulting recombinant EpC1 glutathione S-transferase (GST) fusion protein (rEpC1-GST) was expressed in Escherichia coli and was affinity purified against the GST tag. Immunoglobulin G was the dominant antibody isotypes generated against rEpC1-GST. A total of 896 human serum samples were used to evaluate the diagnostic sensitivity and specificity of the fusion protein by immunoglobulin G immunoblotting; 324 serum samples from patients with cystic echinococcosis (CE), 172 from patients with neurocysticercosis, 89 from patients with alveolar echinococcosis, and 241 from patients with other infections or clinical presentations, as well as 70 from confirmed-negative control subjects, yielded an overall sensitivity of 92.2% and an overall specificity of 95.6%. The combined levels of sensitivity and specificity achieved with the rEpC1-GST fusion protein for diagnosis of CE are unprecedented, taking into account the large panel of serum samples that were tested.

Amino Acid Sequence↗
PubMed2003

Real-time monitoring of nucleic acid ligation in homogenous solutions using molecular beacons.

Nucleic acids ligation is a vital process in the repair, replication and recombination of nucleic acids. Traditionally, it is assayed by denatured gel electrophoresis and autoradiography, which are not sensitive, and are complex and discontinuous. Here we report a new approach for ligation monitoring using molecular beacon DNA probes. The molecular beacon, designed in such a way that its sequence is complementary with the product of the ligation process, is used to monitor the nucleic acid ligation in a homogeneous solution and in real-time. Our method is fast and simple. We are able to study nucleic acids ligation kinetics conveniently and to determine the activity of DNA ligase accurately. We have studied different factors that influence DNA ligation catalyzed by T4 DNA ligase. The major advantages of our method are its ultrasensitivity, excellent specificity, convenience and real-time monitoring in homogeneous solution. This method will be widely useful for studying nucleic acids ligation process and other nucleic acid interactions.

DNA Ligases↗