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Biomedical subjects

Song Luo

Publications and source records attributed to Song Luo.

9 recordsLinked to original sources
PubMed2006

[Neuroprotective effect of electroacupuncture therapy on damaged cholinergic neurons in rats with Alzheimer's disease].

OBJECTIVE: To explore the neuroprotective effect of electroacupuncture therapy on damaged cholinergic neurons in hippocampus in aged rats with Alzheimer's disease (AD). METHODS: Thirty six aged male rats were randomly divided into normal control group, sham-operated group, untreated group and electroacupuncture group. Animal model of AD was established with fimbria-fornix transection. The rats in the electroacupuncture group received electroacupuncture on Baihui (DU 20), Yongquan (KI 1), Taixi (KI 3) and Xuehai (SP10). The activity of choline acetyltransferase (ChAT) in septal area of brain was detected by radioimmunoassay, and the protein expressions of nerve growth factor (NGF) and c-fos in CA3 region of hippocampus were detected by immunohistochemical assay. RESULTS: The ChAT activity and the expression levels of NGF and c-fos proteins in the electroacupuncture group were significantly higher than those in the untreated group. CONCLUSION: Electroacupuncture therapy can protect cholinergic neurons in hippocampus in aged rats with AD by means of promoting synthesis of c-fos protein and increasing the expression level of NGF.

Alzheimer Disease↗
PubMed2005

Differential rates of local and global homogenization in centromere satellites from Arabidopsis relatives.

Higher eukaryotic centromeres contain thousands of satellite repeats organized into tandem arrays. As species diverge, new satellite variants are homogenized within and between chromosomes, yet the processes by which particular sequences are dispersed are poorly understood. Here, we isolated and analyzed centromere satellites in plants separated from Arabidopsis thaliana by 5-20 million years, uncovering more rapid satellite divergence compared to primate alpha-satellite repeats. We also found that satellites derived from the same genomic locus were more similar to each other than satellites derived from disparate genomic regions, indicating that new sequence alterations were homogenized more efficiently at a local, rather than global, level. Nonetheless, the presence of higher-order satellite arrays, similar to those identified in human centromeres, indicated limits to local homogenization and suggested that sequence polymorphisms may play important functional roles. In two species, we defined more extensive polymorphisms, identifying physically separated and highly distinct satellite types. Taken together, these data show that there is a balance between plant satellite homogenization and the persistence of satellite variants. This balance could ultimately generate sufficient sequence divergence to cause mating incompatibilities between plant species, while maintaining adequate conservation within a species for centromere activity.

Amino Acid Sequence↗
PubMed2004

Whole-genome fractionation rapidly purifies DNA from centromeric regions.

The condensed centromeric regions of higher eukaryotic chromosomes contain satellite sequences, transposons and retroelements, as well as transcribed genes that perform a variety of functions. These chromosomal domains nucleate kinetochores, mediate sister chromatid cohesion and inhibit recombination, yet their characterization has often lagged behind that of chromosome arms. Here, we describe a whole-genome fractionation technique that rapidly identifies bacterial artificial chromosome (BAC) clones derived from plant centromeric regions. This approach, which relies on hybridization of methylated genomic DNA, revealed BACs that correspond to the genetically mapped and sequenced Arabidopsis thaliana centromeric regions. Extending this method to other species in the Brassicaceae family identified centromere-linked clones and provided genome-wide estimates of methylated DNA abundance. Sequencing these clones will elucidate the changes that occur during plant centromere evolution. This genomic fractionation technique could identify centromeric DNA in genomes with similar methylation and repetitive DNA content, including those from crops and mammals.

Arabidopsis↗
PubMed2004

[The active expression of CenpB, a constitutive protein in the centromeres of chromosomes, in breast cancer tissues].

At present, a point that cell biologists and medicine scientists focus their close attention on is the mechanisms of cell proliferation and carceration. Breast cancer, one of the frequently occurring cancers, is often been studied intensively. Centromere constitutive molecules, related to various regulatory factors, play an important role in cell proliferation check point regulation. Cell cycle engine molecules, oncogenes, anti-oncogenes and other molecules conform a cell proliferation network. The basic courses of all tumors are associated to this network. However, there are still many problems to be resolved in the analyses of cancer related genes which cause tumors and tumor gene markers. In the current study, using Northern blot, 31 samples of breast cancer tissues and their normal (not cancerous) tissues a little far away from them in the same individuals showed that, in the majority of the tests (87.1%), the mRNA of centromere protein CenpB over expressed in breast cancer tissues, and moreover, tissue in situ hybridization also revealed that all of the CenpB-over-expressed cancer tissues, having identified with Northern blot, over expressed CenpB mRNA. Analyzing the same samples by means of Western blot, the result was highly consistent to the studies in the RNA level. A conclusion was drawn that the over expression of CenpB gene probably relates to malignant cell proliferation in breast gland. It has been testified by researchers that a few of CenpB homogenous proteins are co-operative, the loss of their genes resulting in chromosomes' separating abnormally and cell growth's slowing down. Having transfected HeLa (Tet-Off) cells with anti-sense Cenp in a previous experiment, we ever got a result that cellular duplicating time was prolonged for another 32.8 h, and together with the inhibition of centromere assembly, the mitotic index dropped sharply. In another research, we drew a conclusion that CenpG may be related to cancer, and its differential expressing probably relates to malignant cell proliferation. Combined with these researches, the results obtained from the current study are beneficial to further recognition of the mechanism of cancer.

Autoantigens↗
PubMed2003

Ceramides modulate programmed cell death in plants.

The balance between the bioactive sphingolipid ceramide and its phosphorylated derivative has been proposed to modulate the amount of programmed cell death (PCD) in eukaryotes. We characterized the first ceramide kinase (CERK) mutant in any organism. The Arabidopsis CERK mutant, called accelerated cell death 5, accumulates CERK substrates and shows enhanced disease symptoms during pathogen attack and apoptotic-like cell death dependent on defense signaling late in development. ACD5 protein shows high specificity for ceramides in vitro. Strikingly, C2 ceramide induces, whereas its phosphorylated derivative partially blocks, plant PCD, supporting a role for ceramide phosphorylation in modulating cell death in plants.

Apoptosis↗
PubMed2003

Strand-biased DNA methylation associated with centromeric regions in Arabidopsis.

The Arabidopsis genome project assembled 15 megabases of heterochromatic sequence, facilitating investigations of heterochromatin assembly, maintenance, and structure. In many species, large quantities of methylcytosine decorate heterochromatin; these modifications are typically maintained by methyltransferases that recognize newly replicated hemimethylated DNA. We assessed the extent and patterns of Arabidopsis heterochromatin methylation by amplifying and sequencing genomic DNA treated with bisulfite, which converts cytosine, but not methylcytosine, to uracil. This survey revealed unexpected asymmetries in methylation patterns, with one helix strand often exhibiting higher levels of methylation. We confirmed these observations both by immunoprecipitating methylated DNA strands and by restriction enzyme digestion of amplified, bisulfite-treated DNA. We also developed a primer-extension assay that can monitor the methylation status of an entire chromosome, demonstrating that strand-specific methylation occurs predominantly in the centromeric regions. Conventional models for methylation maintenance do not explain these unusual patterns; instead, new models that allow for strand specificity are required. The abundance of Arabidopsis strand-specific modifications points to their importance, perhaps as epigenetic signals that mark the heterochromatic regions that confer centromere activity.

Arabidopsis↗
PubMed2003

A project plan for construction and cabling of picture archiving and communication system network.

OBJECTIVE: To determine a network solution to meet the network requirements of the heavy data flow, load balance, and potential network storms from expansion of picture archiving and communication system (PACS) application. METHODS: Intel Netstructure 480T Giga Switch was used as the main switch and connected to each building by fiber channel at 1 Giga speed to archive 100 MB/s to each port. At the same time, the in-dependence of the original network construction was physically kept. The layer 3 and 4 switchers were used as load balance to reduce the heavy load of the network, and all the cabling for PACS used the super CAT5 along with the Intel NetStructure 1520 to prepare for potential network storms. RESULTS: An advanced intranet was set up to fully meet the high standard requirement of the PACS. The foundation for upgrading the whole network system to 1 Giga application was built to achieve sharing and transmission of images, information, and patient data within the hospital. The base was established for the standardized management of the hospital. CONCLUSION: Good planning is the first step in setting up PACS, and the equipment forms the necessary platform to run PACS and all kinds of hospital information system (HIS). The networking construction is the foundation of e-hospital.

Computer Communication Networks↗
PubMed2003

Set-up and preliminary performance of a digital radiology conference system.

OBJECTIVE: To investigate the set-up and preliminary performance of a digital radiology conference system and its characteristics. METHODS: The imaging system included a dual-screen image-text workstation with a Matrox G450 demonstration dual-head card, two multimedia projectors, a large screen, and a line-pair and grey scale test card. Patient information on radiology information system (RIS) and images on picture archiving and communication system (PACS) were fetched with GE Radworks software based on Intranet and PACS. The fetching velocity and resolution and grey scale of the images were measured. RESULTS: Patient information in the form of texts and images were demonstrated successfully on two screens with Matrox G450 demonstration dual-head card and switched rapidly between text-image two-screen and image two-screen. The image fetching velocity was fast, the resolution was high, and the grey scale was good. CONCLUSION: The digital conference radiology system is good, and should be popularized.

Audiovisual Aids↗