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Biomedical subjects

Ping Yu

Publications and source records attributed to Ping Yu.

At least 55 records · Page 3Linked to original sources
PubMed2005

[Partial vertical laryngectomy with epiglottis reconstruction--Tucker technique].

OBJECTIVE: To evaluate the results of partial supracricoid laryngectomy with Tucker's reconstruction in T1b and T2 stages of glottic laryngocarcinoma. METHOD: One hundred and thirty-nine patients received partial supracricoid laryngectomy with Tucker's reconstruction were analyzed, among them, 127 patients (T1b-48, T2-79) had never been treated, 12 patients with glottic cancer (Tr) recurred after radiotherapy or cordectomy. We calculate survival rate and evaluate the function of larynx according to the stage. RESULT: For carcinology: 5-years survival rate for T1, T2 and Tr stages was 91%, 86% and 64% respectively; 5-years local control rate for T1, T2 and Tr stages was 100%, 94% and 82% respectively. With respect to the laryngeal function, the rate of decannulation is 100%, the average duration of decannulation is 10 days. The rate of the oblation of the naso-gastric tube is 99.3%. Six patients had accepted gastrotomy with difficulty during the deglutition of liquids; 1 patient had to have total laryngectomy because of incurable disorder of the deglutition. The time of the ablation of the naso-gastric tube is 15 days on average. One hundred and twenty-one patients (87%) presentented a satisfactory voice and only 18 patients have a medium voice quality. CONCLUSION: Tucker technique is a reliable intervention on the carcinology and laryngeal function for the glottic lesions of T1b and T2.

Adult↗
PubMed2005

[Preliminary study on human embryonic kidney cell line HEK-293 after porcine endogenous retrovirus infection].

OBJECTIVE: To assess the infectivity of porcine endogenous retrovirus (PERV) via in vitro infection of human embryonic kidney cell line HEK-293. METHODS: PERV particles were detected by immunoelectron microscopy. PERV DNA and mRNA were studied in HEK-293 24 hours after the infection using polymerase chain reaction and reverse transcriptase-PCR respectively. The PERV types were also analyzed. PERV-gag protein was observed by confocal microscopy. RESULTS: Retroviral particles were round under electron microscope. PERV-gag pol gene and gag protein were detected and expressed in the infected HEK-293 cells. The types of PERV were PERV-A and PERV-B. PERV-gag protein was also identified in the cytoplasm of infected cells by confocal microscopy. CONCLUSIONS: PERV is able to infect HEK-293 cell line in vitro; types of PERV-gag protein is also expressed as a result. Further studies are thus necessary in order to evaluate the possibility of xenozoonoses in pig-to-human xenotransplantation.

Animals↗
PubMed2005

[Studies on the hypoglycemia and lipids regulating effects of Plantago depressa var. montata].

OBJECTIVE: To investigate the effects of Pantago depressa var. montata. Extract (PDM) on the metabolisms of glucose and lipids in mice as well as the underlined mechanism. METHOD: Fasting serum glucose (FSG) in normal mice was determined after oral administration of PDM. The effects of PDM on diabetic mice induced by alloxan were investigated by observing the changes of glucose tolerance, the contents of FSG, glycosylated serum protein (GSP), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO) and the injured degree of pancreatic islet. Effects of PDM on the injured human umbilical vein endothelial cell lines (ECV304) induced by H2O2 were also investigated. RESULT: PDM showed no any significant effect on FSG in normal mice. However, in the mice with diabetes induced by alloxan PDM could remarkably decrease serum glucose tolerance, the contents of FSG, GSP, TC, TG and LDL-C and significantly increased the ratio of HDL-C/TC, the activity of SOD and the concentration of NO. The damage of pancreatic islet induced by alloxan was also significantly attenuated by PDM. Furthermore, PDM promoted the viability of injured ECV304, elevated SOD level and reduced the contents of MDA. CONCLUSION: The results in the present study suggest that PDM can significantly attenuate hyperlipidemia and hyperglycemia in diabetic mice, which are probably due to its effects of antioxidation and amelioration of damaged pancreatic islet induced by free radicals.

Animals↗
PubMed2005

[Intergration and epression of porcine endogenous retrovinus in the immortal cell line of Banna Minipig Inberd Line-Mesenhymal Stem Cells].

OBJECTIVE: To detect the integration and expression of porcine endogenous retrovirus (PERV) in the immortal cell line of Banna Minipig Inbred Line-Mesenchymal Stem Cells (BMI-MSCs). METHODS: DNA and total RNA of the immortal cell line of BMI-MSCs were extracted and PCR, RT-PCR were performed to detect PERV-gag, pol and env gene, and the type of PERV was also detected. RESULTS: PERV-gag, pol and env gene were all detected in the primary culture and immortal cell line (passage 150 and passage 180) of BMI-MSCs, and the type of PERV was PERV-A, B. Functional expression of PERV-gag and pol mRNA was also detected. CONCLUSION: In this laboratory, PERV was not lost during the proceeding of pig inbred and since has been in long-term culture of pig cells in vitro. PERV has integrated into the genome of its natural host, and virus mRNA can effectively express. So it is very essential to evaluate the possibility of xenozoonoses in pig-to-human xenotransplantation.

Animals↗
PubMed2005

[Kinetic spectrophotometric determination of trace chromium(VI) with sensitized function of microemulsion].

A sensitive catalytic spectrophotometric method for determining microg x L(-1) of chromium(VI) has been developed. The method, based on the catalytic effect of Cr(VI)on the oxidation of aligarin red with hydrogen peroxide, was monitored spctrophotornetrically in the medium of microemulsion which consists of CTMAB, n-pentanol, n-heptane and water. The variables affecting the rate of the reaction were investigated. The linearity range of the calibration graph is dependent on the reaction temperature. The sensitivity of this method is 72.5% higher in the microemulsion medium than in CTMAB medium. The apparent active energy of the catalytic reaction is 55.7 kJ x mol(-1). The calibration graph is linear for 2.4-75 microg x L(-1) Cr(VI)at 80 degrees C, the detection limit is 4.27 x 10(-10) g x mL(-1), and the relative standard deviation of eleven determinations of 60 microg x L(-1) Cr(VI)was 1.84%. The method has been successfully applied to the determination of chromium(IV) in the electroplating waste water.

English Abstract↗
PubMed2004

A sudden decline in active membrane-bound TGF-beta impairs both T regulatory cell function and protection against autoimmune diabetes.

Autoimmunity presumably manifests as a consequence of a shortfall in the maintenance of peripheral tolerance by CD4(+)CD25(+) T regulatory cells (Tregs). However, the mechanism underlying the functional impairment of Tregs remains largely undefined. In this study a glutamic acid decarboxylase (GAD) diabetogenic epitope was expressed on an Ig to enhance tolerogenic function, and the resulting Ig-GAD expanded Tregs in both young and older insulitis-positive, nonobese diabetic (NOD) mice, but delayed autoimmune diabetes only in the former. Interestingly, Tregs induced at 4 wk of age had significant active membrane-bound TGF-beta (mTGF-beta) and sustained protection against diabetes, whereas Tregs expanded during insulitis had minimal mTGF-beta and could not protect against diabetes. The Tregs probably operate suppressive function through mTGF-beta, because Ab blockade of mTGF-beta nullifies protection against diabetes. Surprisingly, young Tregs that modulated pathogenic T cells maintained stable frequency over time in the protected animals, but decreased their mTGF-beta at the age of 8 wk. More strikingly, these 8-wk-old mTGF-beta-negative Tregs, which were previously protective, became unable to confer resistance against diabetes. Thus, a developmental decline in active mTGF-beta nullifies Treg function, leading to a break in tolerance and the onset of diabetes.

Aging↗
PubMed2004

Holographic optical coherence imaging of rat osteogenic sarcoma tumor spheroids.

Holographic optical coherence imaging is a full-frame variant of coherence-domain imaging. An optoelectronic semiconductor holographic film functions as a coherence filter placed before a conventional digital video camera that passes coherent (structure-bearing) light to the camera during holographic readout while preferentially rejecting scattered light. The data are acquired as a succession of en face images at increasing depth inside the sample in a fly-through acquisition. The samples of living tissue were rat osteogenic sarcoma multicellular tumor spheroids that were grown from a single osteoblast cell line in a bioreactor. Tumor spheroids are nearly spherical and have radial symmetry, presenting a simple geometry for analysis. The tumors investigated ranged in diameter from several hundred micrometers to over 1 mm. Holographic features from the tumors were observed in reflection to depths of 500-600 microm with a total tissue path length of approximately 14 mean free paths. The volumetric data from the tumor spheroids reveal heterogeneous structure, presumably caused by necrosis and microcalcifications characteristic of some human avascular tumors.

Animals↗
PubMed2004

Targeted deletion of the kynurenine aminotransferase ii gene reveals a critical role of endogenous kynurenic acid in the regulation of synaptic transmission via alpha7 nicotinic receptors in the hippocampus.

It has been postulated that endogenous kynurenic acid (KYNA) modulates alpha7* nicotinic acetylcholine receptor (nAChR) and NMDA receptor activities in the brain.a To test this hypothesis, alpha7* nAChR and NMDA receptor functions were studied in mice with a targeted null mutation in the gene encoding kynurenine aminotransferase II (mKat-2-/- mice), an enzyme responsible for brain KYNA synthesis. At 21 postnatal days, mKat-2-/- mice had lower hippocampal KYNA levels and higher spontaneous locomotor activity than wild-type (WT) mice. At this age, alpha7* nAChR activity induced by exogenous application of agonists to CA1 stratum radiatum interneurons was approximately 65% higher in mKat-2-/- than WT mice. Binding studies indicated that the enhanced receptor activity may not have resulted from an increase in alpha7* nAChR number. In 21-d-old mKat-2-/- mice, endogenous alpha7* nAChR activity in the hippocampus was also increased, leading to an enhancement of GABAergic activity impinging onto CA1 pyramidal neurons that could be reduced significantly by acute exposure to KYNA (100 nM). The activities of GABA(A) and NMDA receptors in the interneurons and of alpha3beta4* nAChRs regulating glutamate release onto these neurons were comparable between mKat-2-/- and WT mice. By 60 d of age, KYNA levels and GABAergic transmission in the hippocampus and locomotor activity were similar between mKat-2-/- and WT mice. Our findings that alpha7* nAChRs are major targets for KYNA in the brain may provide insights into the pathophysiology of schizophrenia and Alzheimer's disease, disorders in which brain KYNA levels are increased and alpha7* nAChR functions are impaired.

Acetylcholine↗
PubMed2004

Priming of naive T cells inside tumors leads to eradication of established tumors.

The tumor barrier comprised of nonantigenic stromal cells may contribute to the failure of tumor rejection. The tumor-necrosis factor superfamily member LIGHT (also known as TNFSF-14) is a ligand of stromal cell-expressed lymphotoxin-beta receptor and T cell-expressed herpes viral entry mediator (HVEM). Here we show that forced expression of LIGHT in the tumor environment induces a massive infiltration of naive T lymphocytes that correlates with an upregulation of both chemokine production and expression of adhesion molecules. Activation of these infiltrating T cells, possibly through HVEM, leads to the rejection of established, highly progressive tumors at local and distal sites. Our study indicates that targeting the tumor barrier may be an effective strategy for cancer immunotherapy.

Animals↗
PubMed2004

NMR structural studies of domain 1 of receptor-associated protein.

The 39 kDa receptor-associated protein (RAP) is an endoplasmic reticulum resident protein that binds tightly to the low-density lipoprotein receptor-related protein (LRP) as well as to other members of the low-density lipoprotein receptor superfamily. The association of RAP with LRP prevents this receptor from interacting with ligands. RAP is a three-domain protein that contains two independent LRP binding sites; one located within domains 1 and 2, and one located within domain 3. As the first step toward defining the structure of the full-length protein and understanding the interaction between RAP and this family of receptors, we have determined the 3D structure of domain 1 using constraints derived from heteronuclear multi-dimensional NMR spectra, including NOEs, dihedral angles, J-couplings and chemical shifts, as well as two sets of non-correlated residual dipolar couplings measured from the protein solutions in anisotropic media of Pf1 and 6% polyacrylamide gel. The backbone C(alpha) rmsd between the current structure and a homo-nuclear NOE-based structure is about 2 A. The large rmsd mainly reflects the significant differences in helical orientation and in the structural details of the long helix (helix 2) between the two structures.

Acrylic Resins↗
PubMed2004

Effect of Zn(II) on the structure and biological activity of natural beta-NGF.

Only beta-NGF, the subunit of the 7S NGF complex, exhibits NGF activity, but the function of the zinc ion in native beta-NGF has received little attention. Flameless atomic absorption spectroscopy (FAAS) measurements reveal that native beta-NGF contains Zn(II) with a Zn(II)/beta-NGF stoichiometry of 1:14.6. The presence of Zn(II) in the native molecule results in significant changes of the secondary structure and local tertiary structure around Trp(s) with respect to those of apo beta-NGF, as suggested by spectra of fluorescence and circular dichrosim. Stopped-flow studies show that there are at least two steps during the interaction of Zn(II) with the apo form. In comparison with its apo form, the native beta-NGF shows a higher ability to trigger the proliferation of TF1 cells and mediate the survival of PC12. Thus it is most likely that the structural changes caused by the presence of Zn(II) directly lead to the increase in the biological activity of beta-NGF. All results indicate that Zn(II) in native beta-NGF plays an important role in the structure and the biological activity of the protein.

Animals↗
PubMed2004

Biochemical and phenotypic abnormalities in kynurenine aminotransferase II-deficient mice.

Kynurenic acid (KYNA) can act as an endogenous modulator of excitatory neurotransmission and has been implicated in the pathogenesis of several neurological and psychiatric diseases. To evaluate its role in the brain, we disrupted the murine gene for kynurenine aminotransferase II (KAT II), the principal enzyme responsible for the synthesis of KYNA in the rat brain. mKat-2(-/-) mice showed no detectable KAT II mRNA or protein. Total brain KAT activity and KYNA levels were reduced during the first month but returned to normal levels thereafter. In contrast, liver KAT activity and KYNA levels in mKat-2(-/-) mice were decreased by >90% throughout life, though no hepatic abnormalities were observed histologically. KYNA-associated metabolites kynurenine, 3-hydroxykynurenine, and quinolinic acid were unchanged in the brain and liver of knockout mice. mKat-2(-/-) mice began to manifest hyperactivity and abnormal motor coordination at 2 weeks of age but were indistinguishable from wild type after 1 month of age. Golgi staining of cortical and striatal neurons revealed enlarged dendritic spines and a significant increase in spine density in 3-week-old mKat-2(-/-) mice but not in 2-month-old animals. Our results show that gene targeting of mKat-2 in mice leads to early and transitory decreases in brain KAT activity and KYNA levels with commensurate behavioral and neuropathological changes and suggest that compensatory changes or ontogenic expression of another isoform may account for the normalization of KYNA levels in the adult mKat-2(-/-) brain.

Animals↗
PubMed2004

Solution structure of the pseudo-5' splice site of a retroviral splicing suppressor.

Control of Rous sarcoma virus RNA splicing depends in part on the interaction of U1 and U11 snRNPs with an intronic RNA element called the negative regulator of splicing (NRS). A 23mer RNA hairpin (NRS23) of the NRS directly binds U1 and U11 snRNPs. Mutations that disrupt base-pairing between the loop of NRS23 and U1 snRNA abolish its negative control of splicing. We have determined the solution structure of NRS23 using NOEs, torsion angles, and residual dipolar couplings that were extracted from multidimensional heteronuclear NMR spectra. Our structure showed that the 6-bp stem of NRS23 adopts a nearly A-form duplex conformation. The loop, which consists of 11 residues according to secondary structure probing, was in a closed conformation. U913, the first residue in the loop, was bulged out or dynamic, and loop residues G914-C923, G915-U922, and U916-A921 were base-paired. The remaining UUGU tetraloop sequence did not adopt a stable structure and appears flexible in solution. This tetraloop differs from the well-known classes of tetraloops (GNRA, CUYG, UNCG) in terms of its stability, structure, and function. Deletion of the bulged U913, which is not complementary to U1 snRNA, increased the melting temperature of the RNA hairpin. This hyperstable hairpin exhibited a significant decrease in binding to U1 snRNP. Thus, the structure of the NRS RNA, as well as its sequence, is important for interaction with U1 snRNP and for splicing suppression.

Avian Sarcoma Viruses↗
PubMed2004

Codon-optimized cloning, expression and characertization of the C-terminal region of human apoptotic protein GADD34 in Escherichia coli.

The human GADD34 (Growth Arrest and DNA Damage-inducible 34) is the product of an apoptosis- and DNA-damage-inducible gene. The C-terminus domain of GADD34 is highly homologous to HSV-1 gamma-1 34.5, HSV-2 and the African swine fever virus virulence-associated factor NL-S. Among these viral proteins, HSV-1 gamma 34.5 protein is known to prevent apoptosis of viral-infected cells. Because of the difficulty in expressing GADD34 protein or any of its fragments, including the C-terminus (amino acids 533-632) in E. coli, partially due to sub-optimal expression of eukaryotic codons in prokaryotic E. coli, we used a codon-optimized cloning scheme to construct the eukaryotic gene that codes for GADD34(533-632). We derived a novel PCR protocol to assemble 20 oligonucleotides into the synthetic GADD34(533-632) gene. The clear advantage of using this protocol is that the assembled gene is without the mutation and deletion that are usually of a major problem in constructing synthetic genes. The synthetic GADD34(533-632) gene was cloned, expressed, and purified in large quantity. We obtained approximately 50 mg of GADD34(533-632) protein per liter minimum-medium culture. To our knowledge, this is the first report of a large-scale production of the C-terminus of GADD34. The production and purification of GADD34(533-632) in large quantity are essential for structure determination as well as for understanding its interactions with other proteins such as phosphatase 1-alpha using NMR spectroscopy and other biophysical methods.

Amino Acid Motifs↗
PubMed2004

[Preliminary linkage analysis on autosomal dominant microphthalmia with 12 microsatellite markers].

In this preliminary study a Chinese autosomal dominant microphthalmia family were investigated and the linkage analyses were performed with six previously reported loci (CHX10, MITF, RX, MCOP, NNO1, NNO2) and six microsatellite markers on chromosome 11 as well. The allelic polymorphisms of those microsatellite markers were identified by using polymerase chain reaction, polyacrylamide gel electrophoresis and silver-staining techniques. The LOD scores between microsatellite markers and the disease were obtained by using MLINK software. Our results showed that the linkage between the microphthalmia in this family with the 6 known loci could be excluded, indicating that the defect gene in this microphthalmia family was probably distinct from those of previously reported microphthalmia families.

Asian People↗
PubMed2004

[Genetic diversity of common wild rice (Oryza rufipogon Griff) by using SSR markers and phenotypic traits in Guangxi Province].

In this paper, allelic variation and genetic diversity among geographies and growth habit types were studied by using 223 accessions of common wild rice primary core collection in Guangxi Province, with 34 SSR primers locating on 12 chromosomes of rice and 19 phenotypic traits. In the results, 24.91 alleles were detected per locus on average with a range from 7 to 48. Compared to the cultivated rice, the wild rice showed more allelic variations. The ratio of heterozygote of SSR locus was 32.01% on average, and it's range was 1.35% 81.31%. The frequency of heterozygote of SSR locus in Oryza rufipogon Griff was much higher than in Oryza sativa L. The geographical distribution of genetic diversity measured by SSR markers was not completely accordant with that by phenotypic traits. At DNA level, more wild rice individuals and higher genetic diversity were included within the area covering north latitude 22 degrees - 23 degrees and 23 degrees - 24 degrees (comprising Longan, Fusui, Yongning, Xiangzhou, Laibin, Xuanwu, Yulin and Guigang county), which formed the center of genetic diversity. But the center of genetic diversity at the phenotypic level located within north latitude 21 degrees - 22 degrees and 22 degrees - 23 degrees. Among the four growth habit types, the genetic diversity from high to low was found respectively in prostrate type, sloping type, slighting type, and erect type at both DNA and phenotypic levels.

Genetic Markers↗