Biomedical subjects

Xia Li

Publications and source records attributed to Xia Li.

172 records · Page 10Linked to original sources

PubMed2002

Evaluation of in vitro chemosensitivity of vaccine-associated feline sarcoma cell lines to vincristine and paclitaxel.

OBJECTIVE: To determine the in vitro sensitivity of 4 vaccine-associated feline sarcoma (VAFS) cell lines to the chemotherapeutic agents vincristine and paclitaxel. SAMPLE POPULATION: Cell lines derived from 4 VAFS specimens. PROCEDURES: Cell lines were cultured in vitro and individually exposed to various concentrations of vincristine and paclitaxel. Survival was estimated after 24 and 72 hours of exposure to each drug, and the drug concentrations that resulted in 50 and 90% reduction in number of viable cells (IC50 and IC90, respectively) were calculated. RESULTS: Both vincristine and paclitaxel had significant dose-dependent effects on the viability of the VAFS cell lines. After 72 hours of drug exposure, the IC50 and IC90 of vincristine for the 4 cell lines were between 0.005 to 0.039 microg/ml and 0.045 to 1.027 microg/ml, respectively. The IC50 and IC90 values for paclitaxel were between 0.037 to 0.092 microg/ml and 2.450 to 15.413 microg/ml, respectively. CONCLUSIONS: Results of pharmacokinetic studies on vincristine and paclitaxel in other species suggest that concentrations greater than the IC50 values may be possible for both drugs in feline patients as well. The drug concentrations at which viable cell numbers were reduced by 90% may also be attained in vivo for some cases, but detailed information is needed regarding the distribution, concentration, duration of availability, and toxicity of various drugs in cats. Carefully chosen combinations of antineoplastic agents need to be screened to identify treatment protocols that may be further evaluated clinically for the treatment of VAFS.

Animals↗

PubMed2002

[Effect of Chrysanthemum morifolium Ramat on apoptosis of bovine aortic smooth muscle cells]

OBJECTIVE: To observe the effect and the mechanism of Chrysanthemum morifolium Ramat on apoptosis of bovine aortic smooth muscle cells. METHODS: Vascular smooth muscle cells were isolated from thoracic aorta of fetal calf and cultured, then incubated with different concentration of Chrysanthemum morifolium Ramat. Apoptosis was measured by flow cytometry. SOD and MDA were measured by spectrophotometer. RESULTS: We found that: (1) the number of apoptotic cells was reduced from (4.425+/-0.624)% to (2.875+/-0.640)% in Chrysanthemum morifolium Ramat group, in a concentration dependent manner; (2) the value of SOD was increased from (1.683+/-0.149)X10(4) U/L to (2.297+/-0.230)X104 U/L and the value of MDA was reduced from(166.454+/-56.805)&mgr;mol/L to (73.068+/-27.203)&mgr;mol/L in Chrysanthemum morifolium Ramat group, also in a concentration dependent manner. CONCLUSION: Chrysanthemum morifolium Ramat can inhibit apoptosis of vascular smooth muscle cells in a concentration-dependent manner.

Journal Article↗

PubMed2002

Effects of different compounding of formulae on content of gardenoside in Yin Chen Hao decoction.

In order to observe the effects of the ground and intact Zhi Zi (Fructus Gardeniae) and different combinations of the ingredients and refined single Chinese drug granules in Yin Chen Hao Decoction compound prescription on the contents of gardenoside (an effective component of the prescription), the contents of gardenoside were determined with reversed phase high performance liquid chromatography (HPLC), with acetonitrile-water (15:85) as mobile phase, at wave length 238 nm. The results indicated that the gardenoside-decocted-out rates in the decoctions prepared by different combinations of the ingredients with the ground Zhi Zi (Fructus Gardeniae) all were higher significantly than those in the decoction with intact Zhi Zi (Fructus Gardeniae), and generally, different combinations of the ingredients in the decoction had only little effect on the gardenoside-decocted-out rate.

Chromatography, High Pressure Liquid↗

PubMed2002

[The detection of living triploid of Haliotis discus hannai--directly making chromosome sample of mantle and epipedium tentacle].

Ploidy detection method of living body is a very important component part in polyploid breeding. There were few reports about chromosome ploidy detection of adult abalone (Haliotis discus hannai), except preparing adult abalone chromosome by means of chopping method using gill tissues and squashing method using gonad, also with these methods the abalone should be killed for getting these tissues. In polyploid breeding living triploid abalones are needed, so ploidy detection technique of living abalone is especially important. In this paper the orthogonal experiment of three factors and three levels L9(3(4)) using mantle and epipodium tentacle as material of living tissues which were vido immersing in PHA solution for preparing chromosome and count the frequence of cell division was first reported. Three factors and three levels were raising temperature: 16 degrees C, 18 degrees C, 20 degrees C; PHA concentration: 0.5%, 1.0%, 1.5%; sampling time: 5:00-6:00, 17:00-18:00, 23:00-24:00, respectively. The tests were repeated two times. The test results showed that the optimal patterns effecting the mitotic frequency of three factors and three levels in triploid abalone detection of chromosome from mantles and epipodium of living bodies were: raising temperature 20 degrees C, PHA concentration 1.0%, and sampling time 17:00-18:00. The order of three factors was: raising temperature-->PHA concentration-->sampling time. Under optimal pattern of three factors and three levels many clear, proper in length and well-scattered metaphase chromosomes could be obtained. The advantages of preparing chromosome using mantles and epipodium tentacle were sampling convenient, no body size restriction and no influence of survival of abalone. After using PHA treated tissues, mitotic frequency could be improved and 1.00% PHA concentration was the best. The key of chromosome preparation was the cells in mitotic metaphase, so the time of sampling was important. During 17:00-18:00, sampling of abalone many mitotic cells could be obtained because abalones were vigorously active at night. Biological zero degree of abalone was 7.6 degrees C. Under 7.6 degrees C abalone could not grow. At 20 degrees C abalones move and prey the most vigorously and grow fastest. Therefore a lot of cells are in mitotic metaphase.

Animals↗

PubMed2002

[Preliminary analysis on the gene expression profiles of different types of gliomas with cDNA array].

BACKGROUND & OBJECTIVE: There is great signification to classify the molecular pathogenesis of gliomas. Gene chip is able to profile the gene expression of tumors, which may become a new method for studying molecular pathology of tumors. The cDNA was used in order to detect the differences in gene expression profiles of different types of gliomas. METHODS: cDNA probes tagged with 32P were converted from total RNA extracted from 4 samples of 3 different pathological types, including oligodendrogliomas, anaplastic astrocytomas and ependymomas, and one sample of normal human brain tissue as well, which were then hybridized to the Atlas array. After autoradiography, the gene expression profiles were analyzed with the special software and by the cluster analysis. RESULTS: As compared to the normal brain tissue, the number of differential expressed genes in these tumor samples ranging from 11 to 118 was found. These 4 samples could be divided into 3 kinds of types when 107 differential expressed genes were selected to be as the cluster analysis index. This result was in accordance with the neuropathological diagnosis. CONCLUSION: cDNA array is able to profile gene expression in different types of gliomas. Combined with the bioinformational method, we may further obtain useful information about molecular pathology of gliomas.

Gene Expression Profiling↗

PubMed2002

[Synthesis and spectroscopic analysis of complex Eu(o-ClC6H4OCH2COO)3.2,2'-bipy].

This work has synthesized a title complex using rare earth ion Eu3+ with the o-chlorophenoxyacetic acid and 2,2'-bipyridine. The chemical formula of the complex was determined to be Eu(o-ClC6H4OCH2COO)3.2,2'-bipy by elemental analysis, analysis of IR, UV, fluorescence spectra. The ternary turopium complex display intense fluorescence, the intensity of 5D0-->7F2 line in much higher than that of the 5D0-->7F1 line, which shows low symmetry of the Fe3+ ion site in the complex.

2,2'-Dipyridyl↗

PubMedDate not supplied

Rosiglitazone combined with insulin preserves islet beta cell function in adult-onset latent autoimmune diabetes (LADA).

BACKGROUND: LADA is thought to result from the chronic autoimmune destruction of the insulin-producing pancreatic beta cells. In addition to antidiabetic effects, the newly developed insulin sensitizer-thiazolidinediones have the potential to increase the insulin content of islet cells by downregulating local inflammation and autoimmune response. Therefore, we hypothesized that LADA patients might benefit from thiazolidinediones treatment. METHODS: LADA patients, with a fasting C-peptide (FCP) of 0.3 nmol/L or more, were enrolled and randomly assigned to receive subcutaneous insulin alone (insulin group, n = 12) or rosiglitazone plus insulin (insulin + RSG group, n = 11) to compare the impacts on islet beta cell function. Plasma glucose, HbA 1c, fasting C-peptide (FCP) and C-peptide after 2 h 75-g glucose load (PCP) were determined every 6 months. GAD-Ab and C-peptide were measured with radioimmune assays. Islet beta cell function was evaluated by PCP and DeltaCP(DeltaCP = PCP-FCP). RESULTS: All of the 23 patients have been followed up for 6 months, 17 cases for 12 months and 14 for 18 months. (1) During 6 months' follow-up, there were no significant changes for DeltaCP and PCP levels in both groups. (2) PCP and DeltaCP levels in insulin + RSG group patients stayed steady during the 12 months' observation (P = 0.161 for both PCP and DeltaCP), while in the insulin alone group, both FCP (P = 0.021) and PCP (P = 0.028) levels decreased significantly. Furthermore, PCP (P = 0.004) and DeltaCP(P = 0.015) differences between 12th month and baseline were higher in insulin + RSG group than those in the insulin group. (3) When observed up to 18 months, PCP and DeltaCP levels in insulin + RSG group patients still stayed steady, while PCP and DeltaCP levels decreased more in the insulin alone group. CONCLUSIONS: This pilot study suggests that rosiglitazone combined with insulin may preserve islet beta cell function in LADA patients.

Age of Onset↗

PubMedDate not supplied

Novel monoclonal antibodies with specificity for chelated uranium(VI): isolation and binding properties.

A derivative of 1,10-phenanthroline that binds to UO(2)(2+) with nanomolar affinity was found to be a very effective immunogen for the generation of antibodies directed toward chelated complexes of hexavalent uranium. This study describes the synthesis of 5-isothiocyanato-1,10-phenanthroline-2,9-dicarboxylic acid and its use in the generation and functional characterization of a group of monoclonal antibodies that recognize the most soluble and toxic form of uranium, the hexavalent uranyl ion (UO(2)(2+)). Three different monoclonal antibodies (8A11, 10A3, and 12F6) that recognize the 1:1 complex between UO(2)(2+) and 2,9-dicarboxy-1,10-phenanthroline (DCP) were produced by the injection of BALB/c mice with DCP-UO(2)(2+) covalently coupled to a carrier protein. Equilibrium dissociation constants for the binding of DCP-UO(2)(2+) to antibodies 8A11, 10A3, and 12F6 were 5.5, 2.4, and 0.9 nM, respectively. All three antibodies bound the metal-free DCP with roughly 1000-fold lower affinity. The second-order rate constants for the bimolecular association of each antibody with soluble DCP-UO(2)(2+) were in the range of 1 to 2 x 10(7) M(-1) s(-1). Binding studies conducted with structurally related chelators and 21 metal ions demonstrated that each of these three antibodies was highly specific for the soluble DCP-UO(2)(2+) complex. Detailed equilibrium binding studies conducted with three other derivatives of DCP, either complexed with UO(2)(2+) or metal-free, suggested that the antigen binding sites on the three antibodies have significant functional and structural similarities. Biomolecules that bind specifically to uranium will be at the heart of any new biotechnology developed to monitor and control uranium contamination. The three antibodies described herein possess sufficient affinity and specificity to support the development of immunoassays for hexavalent uranium in environmental and clinical samples.

Animals↗

PubMedDate not supplied

Study of apolipoprotein E genetic polymorphism in patients with atherosclerotic cerebral infarction.

OBJECTIVE: To explore the frequency and significance of ApoE gene polymorphisms in Chinese patients with atherosclerotic cerebral infarction (ACI). METHODS: Polymerase chain reaction and gene sequencing, single nucleotide polymorphisms of ApoE gene were used to analyze 33 cases of patients with ACI and 35 controls. RESULTS: The frequencies of ApoE gene single nucleotide polymorphisms 465C/G, 462C/G and 451delC in the ACI group were significantly higher than those in the control group (P<0.05). The prevalence of polymorphism 486G/T in the control group was significantly higher than that in the ACI group (P=0.011). CONCLUSIONS: 465C/G,462C/G and 451delC polymorphisms might be associated with ACI.486GT allele might have protective effect on the pathogenesis of ACI.

Aged↗

PubMedDate not supplied

Peeling off the hidden genetic heterogeneities of cancers based on disease-relevant functional modules.

Discovering molecular heterogeneities in phenotypically defined disease is of critical importance both for understanding pathogenic mechanisms of complex diseases and for finding efficient treatments. Recently, it has been recognized that cellular phenotypes are determined by the concerted actions of many functionally related genes in modular fashions. The underlying modular mechanisms should help the understanding of hidden genetic heterogeneities of complex diseases. We defined a putative disease module to be the functional gene groups in terms of both biological process and cellular localization, which are significantly enriched with genes highly variably expressed across the disease samples. As a validation, we used two large cancer datasets to evaluate the ability of the modules for correctly partitioning samples. Then, we sought the subtypes of complex diffuse large B-cell lymphoma (DLBCL) using a public dataset. Finally, the clinical significance of the identified subtypes was verified by survival analysis. In two validation datasets, we achieved highly accurate partitions that best fit the clinical cancer phenotypes. Then, for the notoriously heterogeneous DLBCL, we demonstrated that two partitioned subtypes using an identified module ("cellular response to stress") had very different 5-year overall rates (65% vs. 14%) and were highly significantly (P < 0.007) correlated with the clinical survival rate. Finally, we built a multivariate Cox proportional-hazard prediction model that included 4 genes as risk predictors for survival over DLBCL. The proposed modular approach is a promising computational strategy for peeling off genetic heterogeneities and understanding the modular mechanisms of human diseases such as cancers.

Databases, Genetic↗