Biomedical subjects

Yan Li

Publications and source records attributed to Yan Li.

At least 415 records · Page 23Linked to original sources

PubMed2005

[Tryptase relation to VEGF in acute leukemia].

In order to investigate the role of tryptase in angiogenesis of acute leukemia (AL), the expressions of tryptase and vascular endothelial growth factor (VEGF) in leukemic cells from 61 patients with AL were examined by using immunocytochemical method, and the correlation between tryptase and VEGF was analyzed. The results showed that tryptase positive expression was found in 15 out of 51 patients with acute myeloid leukemia (AML) (M(1) 1/3, M(2) 7/15, M(3) 5/20, M(5) 2/8). Tryptase positive expression was 29.4% in AML. However, none of 10 patients with acute lymphocytic leukemia (ALL) showed tryptase expression. There were no correlations between the amounts of cells with tryptase expression and patient age, WBC count, numbers of blood or marrow myeloblasts and neutrophil POX. VEGF expression was revealed in 41 patients with AML (80.4%) and only 3 with ALL (30%). Significant correlation has been found between the expression of tryptase and that of VEGF in AML-M(2) (r = 0.65, P < 0.05). It is concluded that tryptase appears to be a myeloid-specific marker in AML and may be involved in the angiogenesis of AML-M(2).

Biomarkers, Tumor↗

PubMed2005

[Establishment of a cell model targeted to NFAT signal transduction pathway for preliminary screening of FK506-like immunosuppressants].

To screen NFAT antagonistic drugs and research signal transduction pathway related to NFAT. Four recombinant vectors were constructed. Each consists of three tandem copies of the human IL-2 distal NFAT-AP1 binding site in the context of the minimal IL-2 enhancer, either the sequence from -326 - +46 or the sequence from -89 - +46 (containing only the TATA box), driving a luciferase reporter gene or a destabilized enhanced green fluorescence protein (d2EGFP) reporter gene, respectively. Transient transfection of Jurkat cells was achieved by electroporation with 5 - 10 microg of the above plasmid and one pulse at 200V, 65ms. Plasmid pEFBos-mNFAT1 constitutively expressing murine full length NFAT1 protein was used for transient cotransfection. The results showed that neither of non-stimulation nor PMA or ionomycin stimulation alone could activate the reporter gene except PMA plus ionomycin costimulation. Furthermore, overexpressed murine NFAT1 augmented the activation of either IL-2 promoter or NFAT-AP1 enhancer drived reporter gene compared to the endogenous did. However, the reporter gene expression was nearly completely inhibited by pretreatment for 1h with FK506 at 5 microg/mL and then stimulation for 6-12h with PMA plus ionomycin in the presence of FK506. These findings indicated that such a transient Jurkat cell model offered a potential platform for preliminary screening of FK506 or CsA-like immunosuppressive agents.

Animals↗

PubMed2005

[Clinical observation on acupuncture and moxibustion for treatment of aorto-arteritis of arterial type in the head and arm].

OBJECTIVE: To search for an effective therapy for aorto-arteritis of arterial type in the head and arm. METHODS: Eighty cases were randomly divided into an acupuncture and moxibustion group and a medication group, 40 cases in each group. Renying (ST 9), Taiyuan (LU 9), Jiquan (HT 1) and other acupoints were selected in the acupuncture group, and the medication group were treated with intravenous dripping of Fufang Danshen Liquid. Their therapeutic effects were observed. RESULTS: The clinical cured rate and the total effective rate were 15.0% and 95.0% in the acupuncture group, and 0 and 75.0% in the medication group, respectively, with a very significant difference between the two groups in the therapeutic effect (P<0.01). CONCLUSION: Acupuncture and moxibustion has a definite therapeutic effect, which is significantly superior to that of the routine medication for aorto-arteritis of arterial type in the head and arm.

Acupuncture Points↗

PubMed2005

[Effects of pricking blood therapy on ACTH contents in the hypothalamus-pituitary-adrenal axis in the rat of experimental allergic rhinitis].

OBJECTIVE: To explore the mechanism of pricking blood therapy (PBT) for allergic rhinitis (AR). METHODS: The model rat of experimental allergic rhinitis (EAR) was established by administration of ovoglohulin and they were divided into five groups randomly: a model group, a PBT group, a TCM point application group, a beclomethasone dipropionate (BDP) treatment group, and a health control group. Adrenocorticotrophic hormone (ACTH) contents in hypothalamus, pituitary gland, adrenal gland and plasma were determined by radioimmunoassay before and after treatment. RESULTS: The ACTH levels in the hypothalamus, pituitary gland, adrenal gland and plasma in the rat of EAR were lower than those in the health control group (P < 0.01). After treatment of pricking blood ther, ACTH levels in the above tissues increased significantly (P < 0.01), with very significant differences (P < 0.01) as compared with the model group, similar to those in the BDP group (P > 0.05). CONCLUSION: Pricking blood therapy has a regulatory action on ACTH in HPA axis of rats with experimental allergic rhinitis.

Adrenocorticotropic Hormone↗

PubMed2005

[LASEK for the correction of residual myopia and astigmatism after LASIK].

OBJECTIVE: To determine the visual and refractive outcome of LASEK for the correction of residual myopia and astigmatism after laser in situ keratomileusis (LASIK). METHODS: In this prospective study of noncomparative case series, LASEK was performed with minimum of 6 months in 66 eyes (34 patients) that developed myopic regression after LASIK. Mean follow-up was 13.2 months after laser ablation (12 to 18 months). The postoperative symptom, epithelial flap, wavefront aberration, and haze formation were investigated. RESULTS: Postoperative results revealed a reduction in the residual myopia and astigmatism. Higher order aberration was increased postoperatively. No eye lost best corrected Snellen visual acuity. No intraoperative or postoperative complications occurred. CONCLUSIONS: LASEK performed in eyes with myopic regression after LASIK result in an improvement in uncorrected visual acuity.

Adult↗

PubMed2005

[Association of C-159T polymorphism in promoter region of CD14 and coronary heart disease].

OBJECTIVE: To investigate the distribution of CD14 promoter gene -159(C>T) polymorphism in Hubei Han population of China and analyze the association of CD14 polymorphisms with coronary heart disease (CHD). METHODS: Genotypes of CD14 were typed in 162 CHD patients and 196 controls by polymerase chain reaction-restriction fragment length polymorphism. Selected coronary angiography was performed in 162 CHD patients. RESULTS: CD14 promoter -159 genotype frequencies of CC, CT and TT were 27.4%, 45.6%, 27.0% and 14.8%, 46.5%, 38.7% in normal control group and CHD group respectively. Genotype distribution was in accordance with Hardy-Weinberg equilibrium. There existed statistically significant difference in frequencies of allele and genotype in CD14 C-159T polymorphism between CHD group and control group (Genotype: Chi2=0.654, P < 0.05, CT vs CC, OR=1.245, 95%CI: 1.001-1.473, TT vs CC, OR=2.374, 95%CI 2.012-2.649; Allele: Chi2=0.547, P < 0.05, T vs C, Chi2=0.547, P < 0.05, OR=3.105, 95%CI: 2.493-3.539). The distributions of allele and genotype in CD14 -159(C>T) were of statistically significant difference between non-myocardial infarction subgroup and myocardial infarction subgroup (Genotype: Chi2=0.782, P < 0.05, CT vs CC, OR=2.375, 95%CI: 2.017-2.689, TT vs CC, OR=3.459, 95%CI: 3.003-3.846. Allele: Chi2=2.374, P < 0.05, T vs C, Chi2=2.374, P < 0.05, OR=4.011, 95%CI: 3.814-4.279). However, no statistically significant difference was found among the subgroups of oneìtwo and three stenosed vessels. CONCLUSION: The T allele of the C-159T polymorphism of CD14 gene may be a risk factor for myocardial infarction.

Adult↗

PubMed2005

[Soil properties and water holding capacites of Michelia macclurei, Schima superba and Castanopis fissa stands].

The study showed that the soil density, total porosity, natural water capacity and capillary moisture capacity were 1.19 g x cm(-3), 56.73%, 15.7% and 43.2% in Michelia nacclurei stand, 1.26 g x cm(-3), 54.18%, 13.0% and 37.8% in Schima superb stand, and 1.06 g x cm(-3), 60.74%, 19.4%, and 45.8% in Castanopsis fissa stand, respectively. Soil water holding capacity and aeration were good in Castanopsis fissa stand but bad in Schima superba stand, whereas Michelia macclurei stand had a medium water holding capacity and a bad aeration. The water holding capacity of litter per tree was in order of Michelia nuacclurei (20 kg) > Castanopsis fissa (15 kg) > Schima superba (8 kg), whereas that of litter in stand was Castanopsis fissa (17 t x hm(-2)) > Michelia macclurei (16 t x hm(-2)) > Schima superba (13 t x hm(-2)). The nutrient storage of litter per tree was 112.71, 31.20 and 87.30 g in Michelia macclurei, Schima superba and Castanopsis fissa stands, respectively, and that of litter in stand was 84.35,51.86 and 98.11 kg x hm(-2), respectively. The soil in the three stands was strong acidic, and the content of soil organic matter, total N, total P, total K, alkalized N, available P and available K was 18.43 g x kg(-1), 0.69 g x kg(-1), 0.17 g x kg(-1), 5.83 g x kg(-1), 45.67 mg x kg(-1), 0.83 mg x kg(-1) and 23.13 mg x kg(-1) in Michelia macclurei stand, 13.40 g x kg(-1), 0.68 g x kg(-1), 0.20 g x kg(-1), 12.32 g x kg(-1), 40.78 mg x kg(-1), 0.85 mg x kg(-1) and 90.63 mg x kg(-1) in Schima superba stand, and 28.50 g x kg(-1), 0.97 g x kg(-1), 0.23 g x kg(-1), 18.77 g x kg(-1), 73.40 mg x kg(-1), 1.45 mg x kg(-1) and 66.50 mg x kg(-1) in Castanopsis fissa stand, respectively. Soil bacteria accounted for > 94% of soil microbes, and their individuals were 41 x 105, 34 x 104 and 5.3 x 104 g(-1) in Michelia macclurei, Schima superba and Castanopsis fissa stands, respectively. The activities of soil urease, catalase and phosphatase in Castanopsis fissa stand were the greatest among the three stands, while soil cellulase activity in Michelia macclurei stand was greater than that in other two stands. In a word, soil fertility of Castanopsis fissa stand was the highest among three test stands.

Ecosystem↗

PubMed2005

[Application and improvement of partial-least-squares in Fourier transform infrared spectroscopy].

Partial least squares(PLS) algorithm is an effective chemometric tool. It takes the advantages of multipal linear regression (MLR) and principal component regression (PCR), which makes Fourier transform infrared spectrometry (FTIR) more powerful and useful. Accompanied with increasing use of FTIR, the algorithm is modified and corrected under different circumstances. The applications of PLS to FTIR were mentioned. Improved algorithms were presented, such as moving windows PLS(MWPLS), robust PLS (RPLS), weighted PLS(WPLS), and non-linear PLS. Data pre-processing, selection of variable, noise elimination and non-linear model of PLS were introduced.

English Abstract↗

PubMed2005

[Advances in passive OP-FTIR].

As an OP-FTIR(Open Path FTIR) technology, passive OP-FTIR not only has the advantages of OP-FTIR, but also has the ability to collect data from any direction without prior background information. This technology allows mobile, fast, man-held and stand-off detection of hazardous chemical cloud.The present paper presents some developments of passive OP-FTIR, including high altitude atmospheric pollution detection, auto-detection of toxic cloud, hot gases detection (such as the determination of major combustion products in aircraft exhausts, remote sensing of smoke plumes, and remote sensing of volcano emissions), temperature and combustion products determination (including cloud temperature determination). The present paper also gives the application of passive OP-FTIR in the military. With the development of FTIR and computer science, more and more applications of OP-FTIR to environment supervision, aviation and space flight, engine exhausts, combustion and military will be fulfilled.

English Abstract↗

PubMed2005

The effect of CD3-specific monoclonal antibody on treating experimental autoimmune myasthenia gravis.

CD3-specific monoclonal antibody was the first one used for clinical practice in field of transplantation. Recently, renewed interests have elicited in its capacity to prevent autoimmune diabetes by inducing immune tolerance. In this study, we tested whether this antibody can also be used to treat another kind of autoimmune disease myasthenia gravis (MG) and explored the possible mechanisms. MG is caused by an autoimmune damage mediated by antibody- and complement-mediated destruction of AChR at the neuromuscular junction. We found that administration of CD3-specific antibody (Fab)2 to an animal model with experimental autoimmune myasthenia gravis (EAMG) (B6 mice received 3 times of AChR/CFA immunization) could not significantly improve the clinical signs and clinical score. When the possible mechanisms were tested, we found that CD3 antibody treatment slightly down-regulated the T-cell response to AChR, modestly up-regulating the muscle strength. And no significant difference in the titers of IgG2b was found between CD3 antibody treated and control groups. These data indicated that CD3-specific antibody was not suitable for treating MG, an antibody- and complement- mediated autoimmune disease, after this disease has been established. The role of CD3-specific antibody in treating this kind of disease remains to be determined.

Animals↗

PubMed2005

[Expression of somatostatin receptor reporter gene and its correlation with targeted imaging in vivo for detection of pancreas carcinoma].

OBJECTIVE: To evaluate the value of (99 m)Tc-sandostatin scintigraphy in targeted diagnosis of pancreas carcinoma and the correlation with expression of somatostatin receptor (SSTR) reporter gene in tumor tissue. METHODS: Nude mice bearing human pancreas carcinoma xenograft were established in advance. (99 m)Tc-sandostatin imaging was performed in 18 nude mice and tumor to normal tissue ratio (T/NT) was calculated. mRNA expression of SSTR1, SSTR2 and SSTR5 in tumor tissue was detected by RT-PCR. RESULTS: Out of 18 nude mice, 13 mice showed intense uptake of (99 m)Tc-sandostatin. Six hours after (99 m)Tc-sandostatin administration, the T/NT ratio was 2.53 +/- 0.84. Five mice showed negative findings, and the T/NT ratio was 1.04 +/- 0.06. Positive correlations were obtained between the T/NT ratio and the expression of SSTR1 and SSTR2 mRNA, especially SSTR2 (r = 0.807, P < 0.01). CONCLUSION: High expression of SSTR1, SSTR2 and SSTR5 mRNA were found in human pancreas tumor xenograft in nude mice, especially SSTR2. There is a significant correlation between the tumor uptake of (99 m)Tc-sandostatin and SSTR2 mRNA level. This approach may allow SSTR-targeted diagnosis and therapy of human pancreas cancer.

Animals↗

PubMed2005

[Polyethylene glycol-accompanied ion-exchange chromatography to purify recombinant hepatitis B virus surface antigen].

The dissociation of virus-like particles of Hepatitis B surface antigen (HBsAg) during the adsorption-desorption on the solid-phase of chromatography is a main challenge for its purification. Herein, poly (ethylene glycol) (PEG) was applied as an additive during the purification of HBsAg from recombinant Chinese hamster ovary (CHO) cell culture to improve the HBsAg recovery and protect its structural assembly. The presence of 1% of PEG10000 in the mobile phase of ion-exchange chromatography (IEC) of DEAE-Sepharose FF column could increase the recovery of HBsAg from about 55% to 80%, with a similar purification (-fold) (about 12) compared with the absence of PEG. Importantly, glycosylated protein forms of HBsAg were reserved well by PEG-accompanied chromatography. Furthermore, size exclusion chromatography-multiangle laser light scattering (SEC-MALLS) analysis was performed on line to monitor the aggregates, particle size and molecular weight distribution of HBsAg. The results demonstrated that the HBsAg particle size and assembly are more homogenous after adding PEG in the mobile phase of IEC than no PEG added in the mobile phase.

Animals↗

PubMed2005

[Study on the intercellular molecule-1 polymorphisms in an Chinese population with myocardial infarction].

OBJECTIVE: To investigate the association between intercellular adhesion molecule-1 (ICAM-1) gene + 12959G/A and + 13848A/G polymorphism and myocardial infarction (MI). METHODS: Polymerase chain reaction-sequence specific primers (PCR-SSP) technology and PCR-restriction fragment length polymorphism(PCR-RFLP) were used for the detection of ICAM-1 genotypes in 165 patients with MI(including acute MI and old MI) and 199 healthy controls. Plasma lipid levels and hyper sensitive C reactive protein (quantitive ELISA method was used) levels were measured in all subjects. RESULTS: + 12959G/A polymorphism was not detected in our study. The frequencies of AA,AG and GG Genotypes of + 13848A/G were 58.2% and 45.7%, 37.0% among patients and 45.2%, 4.8% and 9.0% among controls,respectively. There were statistically significant differences in the distributions of the genotype frequencies (P<0.05) between two groups, and the relative risk suffered from MI of AA genotype was 1.651 times of the GG and GA genotype (OR = 1.651, 95% CI: 1.089-2.504). CONCLUSION: There was no + 12959G/A polymorphism found in Chinese people. The coding single nucleotide polymorphism + 13848 A/G in the exon 6 of ICAM-1 gene was associated to MI and the allele A might serve as a risk factor for MI in Chinese.

Asian People↗

PubMed2005

[Study on spectral behavior of trimethoxyphenylflurone with cadmium in microemulsion].

In the present paper, the spectral behavior of cadmium with trimethoxyphenylflurone (TM-PF) in microemulsion was studied. In the buffer medium of borax-NaOH at pH 10.40, cadmium (II) reacts with TM-PF to form a stable 1:2 complex. Its apparent molar absorptivity is 6.10 x 10(4) L x mol(-1) x cm(-1) at 560 nm. Beer's law is obeyed in the range of 0-0.60 microg x mL(-1). The coexistent metal ions can be separated, and cadmium can be enriched by sulfhydryl dextrane gel (SDG), greatly improving the selectivity and sensibility of the system. The method possesses high sensitivity as well as h igh selectivity, and can be used to determine trace amount of cadmium in environmental samples successfully.

English Abstract↗

PubMed2004

An atlas of differential gene expression during early Xenopus embryogenesis.

We have carried out a large-scale, semi-automated whole-mount in situ hybridization screen of 8369 cDNA clones in Xenopus laevis embryos. We confirm that differential gene expression is prevalent during embryogenesis since 24% of the clones are expressed non-ubiquitously and 8% are organ or cell type specific marker genes. Sequence analysis and clustering yielded 723 unique genes displaying a differential expression pattern. Of these, 18% were already described in Xenopus, 47% have homologs and 35% are lacking significant sequence similarity in databases. Many of them encode known developmental regulators. We classified 363 of the 723 genes for which a Gene Ontology annotation for molecular function could be attributed and found 'DNA binding' and 'enzyme' the most represented terms. The most common protein domains encoded in these embryonic, differentially expressed genes are the homeobox and RNA Recognition Motif (RRM). Fifty-nine putative orthologs of human disease genes, and 254 organ or cell specific marker genes were identified. Markers were found for nasal placode and archenteron roof, organs for which a specific marker was previously unavailable. Markers were also found for novel subdomains of various other organs. The tissues for which most markers were found are muscle and epidermis. Expression of cell cycle regulators fell in two classes, containing proliferation-promoting and anti-proliferative genes, respectively. We identified 66 new members of the BMP4, chromatin, endoplasmic reticulum, and karyopherin synexpression groups, thus providing a first glimpse of their probable cellular roles. Cluster analysis of tissues to measure tissue relatedness yielded some unorthodox affinities besides expectable lineage relationships. In conclusion, this study represents an atlas of gene expression patterns, which reveals embryonic regionalization, provides novel marker genes, and makes predictions about the functional role of unknown genes.

Animals↗

PubMed2004

Altered apoptotic response in MCF 10A cells treated with the equine estrogen metabolite, 4-hydroxyequilenin.

Excessive exposure to synthetic and endogenous estrogens has been associated with the development of cancer in several tissues including the breast. 4-Hydroxyequilenin (4-OHEN), a major catechol metabolite of equine estrogens present in Premarin, an estrogen replacement formulation, has been shown to induce apoptosis and DNA damage in human breast cancer cells. It also has the potential to be a tumor initiator or promoter and complete carcinogen. To further understand the effects and mechanisms of equine catechol estrogen metabolite 4-OHEN action in vitro, human non-tumorigenic mammary epithelial MCF 10A cell line was used to study the toxic effects of 4-OHEN. In this study, we observed that 4-OHEN caused dose-dependent increases in apoptosis and DNA damage as measured by the DAPI nuclear screening assay and the Comet assay, respectively. Interestingly, cells treated with 100 nM 4-OHEN biweekly for 4 weeks became resistant to cisplatin-induced apoptosis. The resistance to apoptosis of the 100 nM 4-OHEN-treated cells was through multiple regulatory mechanisms. Compared to the DMSO-treated cells, the 100 nM 4-OHEN-treated cells had higher GSH levels and total SOD activity, and a stronger GSH response after cisplatin treatment. Expression levels of several genes involved in cell growth, DNA repair, and apoptosis were either up- or down-regulated. These data indicate that long-term low-level equine estrogen metabolite exposure could induce DNA damage and initiate cells to become resistant to apoptosis.

Apoptosis↗

PubMed2004

Late treatment with a protective antigen-directed monoclonal antibody improves hemodynamic function and survival in a lethal toxin-infused rat model of anthrax sepsis.

BACKGROUND: In animal models, treatment with 5H3, a fully human protective antigen-directed monoclonal antibody (PA-MAb), improved survival when administered close to the time of Bacillus anthracis lethal toxin (LeTx) bolus or live bacterial challenge. However, treatment with PA-MAb would be most valuable clinically if it were beneficial even when administered after the onset of shock and lethality due to LeTx. METHODS: We investigated the effects of PA-MAb versus placebo administered in rats (n=324) at the time of or 3, 6, 9, or 12 h after the initiation of a 24-h LeTx infusion. RESULTS: In rats receiving placebo, mean arterial blood pressure (MBP) and heart rate (HR) were decreased in nonsurvivors, compared with those in survivors, at 6 h and then worsened further, with lethality first evident at 8 h (median, 16 h; range, 8-152 h). At each treatment time, survival rates were greater for PA-MAb than for placebo, although improvement was decreased at later treatment times (P=.001, for the effect of time). Compared with placebo, PA-MAb significantly increased MBP during the 12 h after the initiation of treatment, but the increase was greatest for treatment at 3 h; similarly, PA-MAb significantly increased HR at all treatment times. CONCLUSION: In this rat model, improvements in outcome due to PA-MAb were significant when it was administered up to 6 h (and approached significance when administered up to 12 h) after initial exposure to LeTx. Clinically, PA-MAb may be beneficial even when administered after the onset of shock and lethality due to LeTx.

Animals↗

PubMed2004

Effects of lycorine on HL-60 cells via arresting cell cycle and inducing apoptosis.

As a natural anti-cancer alkaloid extracted from Amaryllidaceae, lycorine shows various biological effects on tumor cells. The survival rate of HL-60 cells exposed to lycorine was decreased in a dose-dependent manner with 1 microM as the 50% inhibitory concentration (IC50), cell growth was slowed down by arresting cell cycle at G2/M phase, and cell regeneration potential was inhibited. HL-60 cells exhibited typical apoptotic morphological changes, apoptotic DNA "ladder" pattern, and sub-G1 peak in cell phase distribution, showing apoptosis of HL-60 cells. To further understand the apoptotic molecular mechanism of lycorine on HL-60 cells, caspase activity was tested by colorimetric assay, and the expression of Bcl-2 and Bax proteins was examined by Western blotting. The increase of caspase-8, -9, -3 activities demonstrated that caspase was a key mediator of apoptotic pathways induced by lycorine. Under-expression of Bcl-2 and increase of Bax:Bcl-2 ratio showed that Bcl-2 family proteins were involved in apoptosis. Our finding suggests that lycorine can suppress leukemia growth and reduce cell survival via arresting cell cycle and inducing apoptosis of tumor cells.

Amaryllidaceae Alkaloids↗