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Biomedical subjects

Jun Song

Publications and source records attributed to Jun Song.

At least 37 records · Page 2Linked to original sources
PubMed2005

Analysis of the loss resulting from point defects for an etched diffraction grating demultiplexer by using the method of moments.

An effective method for analyzing the effect of point defects (e.g., dust grains and air bubbles) on an etched diffraction grating demultiplexer is presented by using the method of moments. This method leads to a deep insight into the influence of point defects on the loss of the demultiplexer. Numerical results show that strong resonance losses can be produced at some special point defects and incident light.

Journal Article↗
PubMed2005

Fast analysis method for polarization-dependent performance of a concave diffraction grating with total-internal-reflection facets.

A fast simulation method for a waveguide-based concave grating with total-internal-reflection (TIR) facets is presented using the Kirchhoff-Huygens principle. Unlike the conventional scalar method, modifications are made to take into account the influence of the Goos-Hänchen (GH) shift. The simple method is in good agreement with a numerical method based on rigorous coupled-wave analysis for a wide range of practical device parameters and can provide an insightful physical explanation for the numerical results. It is shown that the GH shift is a main contributing factor for the loss and the polarization-dependent loss of an etched diffraction grating demultiplexer with TIR facets.

Journal Article↗
PubMed2005

[Study on the validation of the computer science application's activity monitor in assessing the physical activity among adults using doubly labeled water method].

OBJECTIVE: Using doubly labeled water method to validate the colmputer science application's activity monitor (CSA) in assessing physical activity of free-living adults in Beijing, in order to develop equations to predict total daily energy expenditure (TEE) and activity related energy expenditure (AEE) from activity counts (AC) and anthropometric variables. METHODS: A total of 72 healthy adults (33 males and 39 females, mean age 43.6 +/- 4.0 yr) were monitored for 7 consecutive days by CSA. TEE was simultaneously measured using doubly labeled water method. Average AC (counts/min(-1)) was compared with TEE, AEE and physical activity level (PAL). RESULTS: Physical activity determined by AC was significantly related to data on energy expenditures: TEE (r = 0.31, P < 0.01), AEE (r = 0.30, P < 0.05), and PAL (r = 0.26, P < 0.05). Multiple stepwise regression analysis showed that TEE was significantly influenced by gender, fat-free mass (FFM) or BMI and AC (R(2) = 0.52 - 0.70) while AEE was significantly influenced by gender, FFM and AC (R(2) = 0.25 - 0.32). CONCLUSION: AC from CSA activity monitor seemed a useful measure in studying the total amount of physical activity in free-living adults while AC significantly contributed to the explained variation in TEE and AEE.

Activities of Daily Living↗
PubMed2005

[Angiogenesis promoting effects of Chinese herbal medicine for activating blood circulation to remove stasis on chick embryo chorio-allantoic membrane].

OBJECTIVE: To observe the angiogenesis promoting effects of clinical common used Chinese herbal medicines (CHM) for activating blood circulation to remove stasis on chick embryo chorio-allantoic membrane (CAM). METHODS: Chicken CAM model was established and mice blood serum containing different kinds of medicines, including Radix Peaoniae rubra, Radix Angelicae sinensis, Flos Carthami, Rhizoma Chuanxiong, Radix Salviae miltiorrhizae, Astragalus membranaceus, and their complex prescriptions, Danggui Buxue Decoction, Xuefu Zhuyu Decoction, Xiongshao Capsule, was applied on it respectively to observe the condition of angiogenesis 72 hrs after incubation. Besides, the normal saline group, blank serum group, blank group and basic fibroblast growth factor (bFGF) group were set up for control. RESULTS: All the CHM applied and bFGF had the CAM angiogenetic promoting effect, among them, Radix Salviae Miltiorrhizae and the three complex prescriptions showed better effects than the three negative control groups in capillary formation and count, with the efficacy similar to that of bFGF. The effect of complex prescriptions was superior to that of single herb except Radix Salviae miltiorrhizae. CONCLUSION: Radix Salviae miltiorrhizae, Danggui Buxue Decoction, Xuefu Zhuyu Decoction and Xiongshao Capsule have good angiogenesis promoting effect on CAM. This study elucidated, from a certain aspect, the mechanism of action of CHM on ischemic diseases, and unfolded the scientific evidence of applying complex prescription.

Angiogenesis Inducing Agents↗
PubMed2004

Gene silencing in androgen-responsive prostate cancer cells from the tissue-specific prostate-specific antigen promoter.

The success of gene therapy using a RNA interference approach relies on small interfering RNA (siRNA) expression from a highly tissue-specific RNA polymerase II promoter rather than from ubiquitous RNA polymerase III. Accordingly, we have developed a prostate-specific vector that expresses siRNAs from the human prostate-specific antigen promoter, a RNA polymerase II promoter. Our data demonstrate androgen-dependent and tissue-specific siRNA-mediated gene silencing in the androgen-responsive prostate cancer cell line, LNCaP. The biological significance was evidenced by altered apoptotic activity through the inhibition of the apoptosis-related regulatory gene. These results demonstrate that siRNA-mediated gene silencing from a tissue-specific RNA polymerase II promoter could be a potential tool for tissue-specific gene therapy.

Androgens↗
PubMed2004

Poly(U) and polyadenylation termination signals are interchangeable for terminating the expression of shRNA from a pol II promoter.

Most short hairpin RNA (shRNA)-expressing vectors use RNA polymerase III promoters, as expression of shRNAs from RNA polymerase II promoters is not well understood, due to the lack of defined transcription initiation sites and functional localization of the transcription termination signal. Here we describe a modified cytomegavirus (CMV) promoter, an RNA polymerase II promoter, to express shRNAs with only four overhangs at the 5' end. The expression of shRNAs from the modified CMV promoter was terminated by the transcription termination, the polyadenylation, or the poly(U) termination signal. These results demonstrated that the poly(U) and polyadenylation termination signals are interchangeable for terminating the expression of shRNAs from the CMV promoter and result in similar efficacies in inhibiting endogenous target genes in mammalian cells.

Base Sequence↗
PubMed2004

Cyclophilin A is required for retinoic acid-induced neuronal differentiation in p19 cells.

Stable transfectants with expression of small interfering RNA for targeting cyclophilin A (CypA) in p19 cells lose their potential for retinoic acid (RA)-induced neuronal differentiation but not Me(2)SO-induced mesodermal differentiation. This difference suggests that CypA is specifically required for the RA-induced neuronal pathway. In addition to the loss of RA-induced RA receptor beta expression and retinoic acid response element (RARE)-binding activity, a dramatic reduction in RA-induced RARE-mediated luciferase activity in the CypA knockdown cell line suggests that CypA affects RARE-mediated regulation of gene expression. Silent mutation of target sequences confirms the specificity of RNA interference in p19 embryonal carcinoma cells. Collectively, our data reveal that a novel function of CypA is required in the processing of RA-induced neuronal differentiation in p19 embryonal carcinoma cells.

Animals↗
PubMed2004

Isolation and characterization of an IAA-responsive gene from Gossypium barbadense L.

The full-length cDNA of an IAA-responsive gene was cloned from Gossypium barbadense L. (designated as Gbiaa-Re) by rapid amplification of cDNA ends (RACE). Gbiaa-Re gene was 1043-bp long and contained a 573-bp open reading frame encoding a polypeptide of 190 amino acid residues. Homology analysis revealed that Gbiaa-Re strongly resembled known plant IAA-responsive genes. The conserved integrated domain "AUX_IAA, AUX/IAA family" resided within the region from L11, to V190 of GbIAA-RE, and the 4 typically conserved domains of IAA-responsive gene family were all found in GbIAA-RE. The secondary structure of GbIAA-RE consisted of 20.53% alpha helix, 13.68% extended strand and 65.79% random coil. In total, 12 phosphorylation sites, 1 N-glycosylation site and 4 O-beta-GlcNAc attachment sites were predicted. Southern blot analysis indicated that Gbiaa-Re belonged to a low-copy gene family. Semi-quantitative PCR analysis indicated that the expression of Gbiaa-Re gene was inducible by IAA. Our studies suggested that Gbiaa-Re was a new member of plant AUX/IAA gene family.

Amino Acid Sequence↗
PubMed2003

Effects of altered expression and localization of cyclophilin A on differentiation of p19 embryonic carcinoma cells.

1. The retinoblastoma susceptibility gene product, p105Rb (RB), is an important regulator in the control of cell proliferation, differentiation, and apoptosis. Several cellular factors that complex with RB and exert their cellular regulatory functions have been identified, such as the RB:cyclophilin A (CypA) complex. 2. CypA is a cytoplasmic immunophilin and known for its involvement in T-cell differentiation and proliferation. Although CypA has a pivotal role in the immune response, its function in other signaling pathways is largely unknown. 3. In this study, we used a model of neuronal differentiation to demonstrate that the nuclear translocation of CypA, the appearance of hypophosphorylated RB and the enhancement of RB: CypA complex formation correlates with retinoic acid induced neuronal differentiation. 4. Inhibition of CypA expression results in repression of both the hypophosphorylated RB and the neuron-specific differentiation marker, class III beta tubulin. 5. The evidence of enriched CypA and colocalization of RB with CypA in the nucleus of primary adult sensory neurons substantiated the important event of RB-mediated neuronal differentiation of p19 EC cells.

Animals↗
PubMed2003

Cloning and molecular characterization of a novel lectin gene from Pinellia ternata.

The full-length cDNA of Pinellia ternata agglutinin (PTA) was cloned from inflorescences using RACE-PCR. Through comparative analysis of PTA gene (pta) and its deduced amino acid sequence with those of other Araceae species, pta was found to encode a precursor lectin with signal peptide and to have extensive homology with those of other Araceae species. PTA was a heterotetrameric mannose-binding lectin with three mannose-binding boxes like lectins from other Araceae and Amaryllidaceae species. Southern blot analysis of the genomic DNA revealed that pta belonged to a low-copy gene family. Northern blot analysis demonstrated that pta constitutively expressed in various plant tissues including root, leaf, stem and inflorescence. The pta cDNA sequence encoding for mature PTA protein was cloned into pET-32a plasmid and the resulting plasmid, pET-32a-PTA containing Trx-PTA fusion protein, was investigated for the expression in E. coli BL21. SDS-PAGE gel analysis showed that the Trx-PTA fusion protein was successfully expressed in E. coli BL21 when induced by IPTG. Artificial diet assay revealed that PTA fusion protein had significant levels of resistance against peach potato aphids when incorporated into artificial diet at 0.1% (w/v). The cloning of the pta gene will enable us to further test its effect in depth on aphids by transferring the gene into crop plants.

Amino Acid Sequence↗
PubMed2003

Isolation and expression of cold-regulated cDNA from Chinese cabbage (Brassica pekinensis).

It has been established that changes in gene expression occur during cold acclimation in a wide range of plants. Here we present a novel cDNA encoding a protein with a calculated molecular mass of 25 kDa, designated cor25, from Brassica pekinensis cv. Zaoshu 5 (Chinese cabbage) that was similar with a cold-regulated Arabidopsis thaliana L. gene, cor47. Protein sequence alignment showed that COR25 had 53.5% of identity with COR47 and 59.6% of identity with ERD10, an Arabidopsis thaliana L. early-responsive gene to dehydration stress. Northern blot analysis revealed that the cor25 expression was cold inducible. Moreover, the transcripts of the cor25 accumulated in plants in response to exogenous application of ABA and water stress. The possible functions of the cold-regulated gene and the mechanism for plants to cope with low temperature are discussed.

Amino Acid Sequence↗
PubMed2003

Molecular cloning and characterization of a new Na+/H+ antiporter gene from Brassica napus.

A new Na+/H+ vacuolar antiporter gene from Brassica napus was cloned. The full-length cDNA of B. napus antiporter gene (BnNHX1, GenBank Acc. No. AY189676) was 1819 bp and contained a 1545 bp open reading frame encoding a protein of 515 amino acids. Homology analysis and molecular modeling revealed that BnNHX1 strongly resembled other Na+/H+ antiporter genes. Its encoded protein belonged to a typical sodium/hydrogen exchanger superfamily and shared consensus sequences within predicted transmemberane segments. Southern blot analysis indicated there were multi-copies of BnNHX1 gene present in B. napus genome, which was different from that in Oryza sativa previously reported. Northern blot analysis revealed that BnNHX1 was salt-inducible and its transcript level was most abundant after 24 h treatment with 200 mM sodium chloride. Our studies suggested that BnNHX1 was a new member of the family of recently cloned plant NHX-genes.

Amino Acid Sequence↗
PubMed2003

Transcriptional regulation by zinc-finger proteins Sp1 and MAZ involves interactions with the same cis-elements.

Various transcription factors, such as Sp1 and MAZ, include C2H2-type zinc-finger motifs and are able to bind to GC-rich cis-elements that are distributed in the promoter regions of numerous mammalian genes. The consensus sequence of Sp1-binding sites is very similar to that of MAZ-binding sites. In fact, Sp1 and MAZ bind to the same cis-elements in the promoters of the genes for the receptor for serotonin 1A (HT1Ar), endothelial nitric-oxide synthase (eNOS), phenylethanolamine N-methyltransferase (PNMT), the receptor for parathyroid hormone (PTHr), MAZ and the major late promoter of adenovirus (AdMLP). It appears that two consecutive zinc-finger motifs of Sp1 and MAZ might be essential for the interaction of each protein with DNA. Sp1 and MAZ activated the expression of the genes for HT1Ar and PTHr, as well as AdMLP. Both Sp1 and MAZ inhibited the expression of the gene for MAZ, while expression of the gene for eNOS was enhanced by Sp1 and repressed by MAZ. These observations suggest that both Sp1 and MAZ might have dual functions in the regulation of gene expression. Our results suggest, furthermore, that histone deacetylases are involved in autorepression of the gene for MAZ, while expression of DNA methyltransferase I is associated with suppression of the expression of the gene for MAZ by Sp1. Thus, both deacetylation and methylation might be involved in the regulation of expression of individual genes, with different zinc-finger proteins binding to the same cis-elements but recruiting different proteins, such as methylases and acetylases, to the transcriptional complex.

Amino Acid Sequence↗
PubMed2002

Effects of pregnancy cocaine exposure on the mother and fetus: a murine model.

The aim of the experiments was to develop and characterize a murine model for investigating the effects of prenatal cocaine exposure on the mother and fetus. Pregnant mice were separated into three groups: group 1 was treated with cocaine HCl at 10 mg/kg twice daily (COC); group 2 was treated with saline at 10 ml/kg twice daily (SAL); and group 3 was pair-fed with the COC dams and was injected with saline following the same schedule (SPF) from embryonic day (E) 8 to 17. We utilized high-pressure liquid chromatography (HPLC) with UV detector and electrochemical detector to test the concentrations of cocaine, dopamine and serotonin, as well as HE staining to observe morphological alterations of liver and placenta. Though less food intake and lower weight gain were observed in COC and SPF groups but not in SAL dams, lower fetal body weight and brain weight were only seen in COC offspring. Pharmacological analysis revealed that cocaine was found in fetal plasma at 15 min following intraperitoneal administration on E17, accompanied with elevated concentrations of dopamine (DA) and serotonin (5-HT) in fetal brain. We also observed morphological changes in liver and placenta of cocaine-exposed fetuses. The present study indicates that pregnancy cocaine exposure can lead to maternal undernutrition and developmental abnormality of the fetal brain, liver and placenta. It is suggested that the developmental abnormality of the fetuses induced by cocaine is due to the toxicological effect of cocaine but not to maternal undernutrition.

Animals↗