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Li Cai

Publications and source records attributed to Li Cai.

At least 19 recordsLinked to original sources
PubMed2006

Role of topoisomerase IIbeta in the expression of developmentally regulated genes.

Mice lacking topoisomerase IIbeta (TopIIbeta) are known to exhibit a perinatal death phenotype. In the current study, transcription profiles of the brains of wild-type and top2beta knockout mouse embryos were generated. Surprisingly, only a small number (1 to 4%) of genes were affected in top2beta knockout embryos. However, the expression of nearly 30% of developmentally regulated genes was either up- or down-regulated. By contrast, the expression of genes encoding general cell growth functions and early differentiation markers was not affected, suggesting that TopIIbeta is not required for early differentiation programming but is specifically required for the expression of developmentally regulated genes at later stages of differentiation. Consistent with this notion, immunohistochemical analysis of brain sections showed that TopIIbeta and histone deacetylase 2, a known TopIIbeta-interacting protein, were preferentially expressed in neurons which are in their later stages of differentiation. Chromatin immunoprecipitation analysis of the developing brains revealed TopIIbeta binding to the 5' region of a number of TopIIbeta-sensitive genes. Further studies of a TopIIbeta-sensitive gene, Kcnd2, revealed the presence of TopIIbeta in the transcription unit with major binding near the promoter region. Together, these results support a role of TopIIbeta in activation/repression of developmentally regulated genes at late stages of neuronal differentiation.

Animals↗
PubMed2006

Studies of Langmuir-Blodgett films of an ion pair metal complex containing Eu(III)-Ru(II) dual chromophores.

A surfactant ion-pair complex, [Ru(bpy)(2)L][Eu(NTA)(4)](2) (in which L = 1-docosyl-2-(2- pyridyl)benzimidazole, bpy = 2,2'-bipyridine, and NTA = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedionato) has been synthesized. The surface pressure-area isotherm measurements show that the complex forms a stable Langmuir film at the air-water interface without adding any electrolytes into the subphase. The monolayers formed at the surface pressures of 5 mN m(-1) and 20 mN m(-1), have been successfully transferred onto glass and quartz substrates with the transfer ratios close to unity. The Langmuir-Blodgett films were studied by UV-visible, infrared, and emission spectroscopies, atomic force microscopy, and cyclic voltammetry. The optical, redox, and morphology properties of the LB films were found to be significantly affected by the target surface pressures used for the film depositions.

Journal Article↗
PubMed2006

Testing differences between nested covariance structure models: Power analysis and null hypotheses.

For comparing nested covariance structure models, the standard procedure is the likelihood ratio test of the difference in fit, where the null hypothesis is that the models fit identically in the population. A procedure for determining statistical power of this test is presented where effect size is based on a specified difference in overall fit of the models. A modification of the standard null hypothesis of zero difference in fit is proposed allowing for testing an interval hypothesis that the difference in fit between models is small, rather than zero. These developments are combined yielding a procedure for estimating power of a test of a null hypothesis of small difference in fit versus an alternative hypothesis of larger difference.

Analysis of Variance↗
PubMed2006

Limited-information goodness-of-fit testing of item response theory models for sparse 2 tables.

Bartholomew and Leung proposed a limited-information goodness-of-fit test statistic (Y) for models fitted to sparse 2(P ) contingency tables. The null distribution of Y was approximated using a chi-squared distribution by matching moments. The moments were derived under the assumption that the model parameters were known in advance and it was conjectured that the approximation would also be appropriate when the parameters were to be estimated. Using maximum likelihood estimation of the two-parameter logistic item response theory model, we show that the effect of parameter estimation on the distribution of Y is too large to be ignored. Consequently, we derive the asymptotic moments of Y for maximum likelihood estimation. We show using a simulation study that when the null distribution of Y is approximated using moments that take into account the effect of estimation, Y becomes a very useful statistic to assess the overall goodness of fit of models fitted to sparse 2(P) tables.

Binomial Distribution↗
PubMed2006

Multi-response permutation procedure as an alternative to the analysis of variance: an SPSS implementation.

A permutation test typically requires fewer assumptions than does a comparable parametric counterpart. The multi-response permutation procedure (MRPP) is a class of multivariate permutation tests of group difference useful for the analysis of experimental data. However, psychologists seldom make use of the MRPP in data analysis, in part because the MRPP is not implemented in popular statistical packages that psychologists use. A set of SPSS macros implementing the MRPP test is provided in this article. The use of the macros is illustrated by analyzing example data sets.

Behavioral Research↗
PubMed2006

Cost-effectiveness analysis of influenza and pneumococcal vaccinations among elderly people in Japan.

During the periods of seasonal flu in 2003 and 2004, it was found that about 45 percent of elderly people in Japan had been inoculated with influenza vaccines. Comparatively, however, the proportion of inoculation with pneumococcal vaccine was only 0.1 percent. Taking into account such incongruent proportions, this study assesses health and economic benefits of vaccination strategies for both influenza and pneumonia particularly for the elderly population in Japan. To accomplish this objective, a cost-effectiveness analysis was conducted with the use of the Monte Carlo simulation based on the data from medical literature as well as from the public organizations, wherein three strategic patterns were delineated and compared (i) no vaccination (ii) influenza vaccine only, and (iii) combined influenza with pneumococcal vaccines. The cost for one year of life saved by each strategy was compared with the scenario of no vaccinations. It was found that for 100,000 elderly people over 65 years of age in Japan, the cost-effectiveness ratio of influenza-only vaccination was 516,332 Japanese yen per one year of life saved, while the combined vaccinations of influenza with pneumococcal was 459,874 Japanese yen for the same benefit. The incremental cost-effectiveness ratio of the strategies (iii) versus (ii) was 426,698 Japanese yen per one year of life saved for 100,000 people. Consequently it was indicated that the combined vaccinations would be more cost-effective than the vaccination for influenza only.

Aged↗
PubMed2006

[Analysis of genes related to sensitivity to navalbine and docetaxel in 10 lung cancer cell lines].

OBJECTIVE: To analyze the drug-sensitivity-related genes to anti-tumor drugs navalbine (NVB) and docetaxel (Doc) in four SCLC and six NSCLC cell lines. METHODS: The sensitivity of 4 SCLC lines and 6 NSCLC lines to NVB and to Doc was determined with MTT test. The expression of 1291 anti-tumor drug sensitivity-related genes in the 10 cell lines was assayed by cDNA macroarray technique, and cluster analysis was performed to find the relationship between the results obtained by the above mentioned two measurements. RESULTS: (1) The anti-tumor effect of NVB on the 10 cell lines was apparently better than that of Doc. (2) The drug sensitivity-related genes in these 10 cell lines showed a more close positive correlation with Doc than that with NVB, whereas more genes showed negative correlation with NVB than that with Doc. But in 6 NSCLC cell lines, more genes showed the same positive or negative correlation with the two drugs. (3) 51 genes in the 10 cell lines showed correlation with Doc or NVB. 13 of them had negative correlation with Doc, 11 of them showed positive correlation. 24 of them showed negative correlation with NVB, 3 of them showed positive correlation. 67 genes in 6 NSCLC cell lines showed a correlation with sensitivity to Doc or NVB, among them 34 had negative correlation with Doc, 4 had positive correlation. 25 genes had negative correlation with NVB, 4 had positive correlation. (4) Rab 1, Rab 3, Rho B, Rho C, Rac 1, Rac 2, Gho GDI beta, CD44, integrin alpha5, integrin alpha6, integrin beta5, vinculin showed to be cytoskeleton-related genes differently expressing in SCLC or NSCLC cell lines. CONCLUSION: There is obvious difference in the drug sensitivity-related genes to NVB or Doc between SCLC and NSCLC cell lines.

Antineoplastic Agents↗
PubMed2005

[Application of keyhole approach in operation of intracranial aneurysms].

OBJECTIVE: To explore the operative technique and evaluate the effect of intracranial aneurysms via keyhole approach. METHODS: Fifty-six intracranial aneurysm patients, 23 with anterior communicating artery (AcomA) aneurysm, 29 with posterior communicating artery (PcomA) aneurysm, and 4 with internal carotid artery-posterior communicating artery aneurysm, totally with 58 lesions, were treated by microsurgery, via supraorbital keyhole approach in 22 cases, pterional approach in 18, and transorbital approach in 16. Adjuvant endoscopy was used in 33 patients. RESULTS: Fifty-eight lesions of aneurysm were clipped in all the patients and no one died. No approach-related severe complication occurred. Bilateral PcomA aneurysms in 2 cases were clipped via unilateral keyhole approach. CONCLUSION: It is workable to treat intracranial aneurysms via keyhole approach. Keyhole approach not only reduces the operation-related trauma and shorten the operation time, but also obtains ideal results.

Adult↗
PubMed2005

Distinct epigenetic changes in the stromal cells of breast cancers.

Increasing evidence suggests that changes in the cellular microenvironment contribute to tumorigenesis, but the molecular basis of these alterations is not well understood. Although epigenetic modifications of the neoplastic cells in tumors have been firmly implicated in tumorigenesis, it is not known whether epigenetic modifications occur in the non-neoplastic stromal cells. To address this question in an unbiased and genome-wide manner, we developed a new method, methylation-specific digital karyotyping, and applied it to epithelial and myoepithelial cells, stromal fibroblasts from normal breast tissue, and in situ and invasive breast carcinomas. Our analyses showed that distinct epigenetic alterations occur in all three cell types during breast tumorigenesis in a tumor stage- and cell type-specific manner, suggesting that epigenetic changes have a role in the maintenance of the abnormal cellular microenvironment in breast cancer.

Breast Neoplasms↗
PubMed2005

Effects of navelbine and docetaxel on gene expression in lung cancer cell strains.

AIM: To search genes sensitivity to the anti-cancer drugs navelbine (NVB) and docetaxel (DOC) in small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) cell strains. METHODS: The sensitivity of 4 strains of SCLC and 6 strains of NSCLC to NVB and DOC was evaluated using the MTT assay. The expression of 1291 sensitive-related genes to the anti-cancer drugs in 10 lung cancer cell strains was measured using cDNA macroarrays and the relationship was analyzed. RESULTS: In total, there were 56 (r > or = 0.4) genes sensitive to NVB and DOC. For NVB: 36 genes were sensitive to NVB, 20 co-expressed genes between the SCLC+NSCLC set and the NSCLC set; 27 expressed genes and 7 specially expressed genes in the SCLC+NSCLC set; and 29 expressed genes and 9 specially expressed genes in the NSCLC set. For DOC, 50 genes were sensitive to DOC, 12 co-expressed genes between the SCLC+NSCLC set and the NSCLC set; 24 expressed genes and 12 specially expressed genes in the SCLC+NSCLC set; and 38 expressed genes and 26 specially expressed genes in the NSCLC set. The genes sensitive to NVB and DOC in lung-cancer cell stains were mainly divided into the following 4 categories: signal transduction molecules, cell factors, transcription factors and metabolism-related enzymes and inhibitors. CONCLUSIONS: There were obvious differences in genes related to NVB and DOC between SCLC and NSCLC cell strains, but the same as categories of function.

Antineoplastic Agents, Phytogenic↗
PubMed2005

[Cold storage of platelet suspension by adding trehalose].

The study was aimed to explore the trehalose method for storing platelets in cold. (51)Cr-labeling platelet was used to detect the platelet survival. The platelet function in vitro was performed by platelet aggregate analyzer. After treatment with 50 mg/ml trehalose at 37 degrees C for 4 hours, the rabbit platelet concentrates (PC, 2.0 x 10(9)/ml) were stored in 4-8 degrees C refrigeration, the platelet function in vitro and survival of chilled platelets transfused into self-rabbits were observed. The results showed that trehalose could protect the chilled rabbit platelets. After PC stored at 20-24 degrees C and 4-8 degrees C for up to 24 hours, the platelet aggregate in vitro in response to 11.2 micromol/L ADP were (75.3 +/- 9.8)% and (80.5 +/- 12.5)%, the survival of PC stored at 20-24 degrees C and 4-8 degrees C for 24, 48, 72 hours after transfused into self-rabbits were (78.1 +/- 7.9)%, (65.4 +/- 6.7)%, (57.5 +/- 7.2)% and (5.1 +/- 2.5)%, (2.8 +/- 2.0)%, (0.9 +/- 0.8)%, respectively. The PC treated with 50 mg/ml trehalose were remained stable for up to 12 days of refrigerated storage in autologous plasma. The platelet aggregate in vitro in response to 11.2 micromol/L ADP at 12 days after stored in refrigeration was (77.8 +/- 9.5)%, the survival on 24, 48, 72 hours of platelet transfused into self-rabbits were (75.7 +/- 11.0)%, (67.0 +/- 8.5)%, (56.8 +/- 8.0)%, respectively. Compared with control group of storing at 20-24 degrees C for 24 h, P > 0.05. In conclusion, trehalose can protect the chilled blood platelets, prolong the circulation of refrigerated rabbit platelets, and not impair chilled rabbit platelet function.

Adenosine Diphosphate↗
PubMed2005

[Application of cationic propyl gallate as inducer of thrombocyte aggregation for evaluating the platelet function of platelet donors].

The purpose of study was to investigate the feasibility of the application of cationic propyl gallate (C-PG) as inducer of platelet aggregation for evaluating the platelet function of single-donor plateletpheresis and identifying the incidence of defective platelet function among donors. Experiments were as follows: 3 healthy volunteers' platelet aggregation induced by 100-300 micromol/L C-PG was determined by LG-PABER analyzer to observe the effect of C-PG concentration on platelet aggregation; 30 healthy volunteers' platelet aggregation before and 24 hours after administration of 200-400 mg acetylsalicylic acid (ASA) was examined after induction by 200 micromol/L C-PG for determining the cut-off value to discriminate platelet dysfunction donors; the platelet aggregation of 483 platelet donors was detected and the activated plasma clotting time (APCT) of donors who have deficiency in platelet aggregation was examined for investigating the incidence of defective platelet function among donors. The results showed that platelets were activated by C-PG induction in a dose dependent manner, when concentration of C-PG reached 200 micromol/L, the percentage of platelet aggregation was highest. It significantly decreased after 24 hours with ASA than that before the administration (P < 0.001), especially in 180 seconds induced by C-PG. If cut-off point was fixed on the platelet aggregation < 20% in 180 seconds, donors of platelet dysfunction can be selected effectively. 25 of defective platelet aggregation function among 483 donors were detected, and 11 out of 25 platelet dysfunction donors had the deficiency in procoagulant activity with prolonged APCT. It is concluded that C-PG as inducer of platelet aggregation is feasible to screen the platelet function of donors. Five percent of platelet donors has function defect examined by C-PG as inducer of platelet aggregation.

Antioxidants↗
PubMed2004

Insights into developmental mechanisms and cancers in the mammalian intestine derived from serial analysis of gene expression and study of the hepatoma-derived growth factor (HDGF).

The vertebrate intestine is a model for investigating inductive cellular interactions and the roles of epithelial stem cells in tissue regeneration, and for understanding parallels between development and cancer. We have used serial analysis of gene expression to measure transcript levels across stages in mouse intestine development. The data (http://genome.dfci.harvard.edu/GutSAGE) identify novel differentiation products, potential effectors of epithelial-mesenchymal interactions, and candidate markers and regulators of intestinal epithelium. Transcripts that decline significantly during intestine development frequently are absent from the adult gut. We show that a significant proportion of such genes may be reactivated in human colon cancers. As an example, hepatoma-derived growth factor (HDGF) mRNA is expressed prominently in early gut tissue, with substantially reduced levels after villous epithelial differentiation. HDGF expression is dramatically increased in human colorectal cancers, especially in tumors proficient in DNA mismatch repair, and thus represents a novel marker for a distinctive tumor subtype. HDGF overexpression in fetal intestine explants inhibits maturation, suggesting a role in epithelial differentiation. To investigate the molecular basis for HDGF functions, we isolated components of a nuclear HDGF complex, including heterogeneous nuclear ribonucleoproteins implicated in processing RNA. These genes are regulated in tandem with HDGF during intestine development and one factor, TLS/Fus, is commonly overexpressed in colon cancers. Tumor expression of fetal genes may underlie similarities between developing and malignant tissues, such as self-renewal, invasion and angiogenesis. Our findings also advance understanding of HDGF functions and implicate this developmentally regulated gene in RNA metabolic pathways that may influence malignant behaviors in colorectal cancer.

Animals↗
PubMed2004

Clustering analysis of SAGE data using a Poisson approach.

Serial analysis of gene expression (SAGE) data have been poorly exploited by clustering analysis owing to the lack of appropriate statistical methods that consider their specific properties. We modeled SAGE data by Poisson statistics and developed two Poisson-based distances. Their application to simulated and experimental mouse retina data show that the Poisson-based distances are more appropriate and reliable for analyzing SAGE data compared to other commonly used distances or similarity measures such as Pearson correlation or Euclidean distance.

Animals↗
PubMed2004

Genomic analysis of mouse retinal development.

The vertebrate retina is comprised of seven major cell types that are generated in overlapping but well-defined intervals. To identify genes that might regulate retinal development, gene expression in the developing retina was profiled at multiple time points using serial analysis of gene expression (SAGE). The expression patterns of 1,051 genes that showed developmentally dynamic expression by SAGE were investigated using in situ hybridization. A molecular atlas of gene expression in the developing and mature retina was thereby constructed, along with a taxonomic classification of developmental gene expression patterns. Genes were identified that label both temporal and spatial subsets of mitotic progenitor cells. For each developing and mature major retinal cell type, genes selectively expressed in that cell type were identified. The gene expression profiles of retinal Müller glia and mitotic progenitor cells were found to be highly similar, suggesting that Müller glia might serve to produce multiple retinal cell types under the right conditions. In addition, multiple transcripts that were evolutionarily conserved that did not appear to encode open reading frames of more than 100 amino acids in length ("noncoding RNAs") were found to be dynamically and specifically expressed in developing and mature retinal cell types. Finally, many photoreceptor-enriched genes that mapped to chromosomal intervals containing retinal disease genes were identified. These data serve as a starting point for functional investigations of the roles of these genes in retinal development and physiology.

Animals↗
PubMed2004

Molecular characterization of the tumor microenvironment in breast cancer.

Here we describe the comprehensive gene expression profiles of each cell type composing normal breast tissue and in situ and invasive breast carcinomas using serial analysis of gene expression. Based on these data, we determined that extensive gene expression changes occur in all cell types during cancer progression and that a significant fraction of altered genes encode secreted proteins and receptors. Despite the dramatic gene expression changes in all cell types, genetic alterations were detected only in cancer epithelial cells. The CXCL14 and CXCL12 chemokines overexpressed in tumor myoepithelial cells and myofibroblasts, respectively, bind to receptors on epithelial cells and enhance their proliferation, migration, and invasion. Thus, chemokines may play a role in breast tumorigenesis by acting as paracrine factors.

Biomarkers, Tumor↗
PubMed2003

Cardiac conductive system excitation maps using intracardiac tissue Doppler imaging.

OBJECTIVE: To precisely visualize cardiac anatomic structures and simultaneously depict electro-mechanical events for the purpose of precise underblood intervention. METHODS: Intracardiac high-resolution tissue Doppler imaging was used to map real time myocardial contractions in response to electrical activation within the anatomic structure of the cardiac conductive system using a canine open-chest model. RESULTS: The detailed inner anatomic structure of the cardiac conductive system at different sites (i.e., sino-atrial, atrial wall, atrial-ventricular node and ventricular wall) with the inside onset and propagation of myocardial velocity and acceleration induced by electrical activation was clearly visualized and quantitatively evaluated. CONCLUSION: The simultaneous single modality visualization of the anatomy, function and electrical events of the cardiac conductive system will foster target pacing and precision ablation.

Animals↗