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Biomedical subjects

W Song

Publications and source records attributed to W Song.

At least 91 records · Page 5Linked to original sources
PubMed2000

Rapid assay of A1c-type glycosylated hemoglobin in blood of diabetic rats using fast protein liquid chromatography.

AIM: To develop a fast protein liquid chromatography (FPLC) method for the assay of Alc-type glycosylated hemoglobin in diabetic rats. METHODS: Venous blood was collected from rats. After the erythrocytes were washed and sedimented, the hemolysate was prepared and diluted with isotonic saline as a sample for the assay. Samples were then separated on Mono_S_HR_5/5 cation exchange column by a lithium chloride gradient elution system. The Alc-type glycosylated hemoglobin was monitored by measuring the absorbance at 415 nm. RESULTS: The Alc-type glycosylated hemoglobin was well separated from total hemoglobin. The average HbAlc amount in diabetic rats was determined to be (3.6% +/- 0.6%, n = 7), while the corresponding figure in normal rats was (1.4% +/- 0.4%, n = 7, P < 0.01). CONCLUSION: This FPLC method is easy, rapid and reproducible, and can be used for an assay of diabetic rat HbAlc to evaluate and screen new drugs for diabetes mellitus therapy.

Animals↗
PubMed2000

[The diagnosis and treatment of microgenia].

OBJECTIVE: This article is to elucidate the indications of horizontal advancement osteotomy of the mandible or bone grafting for microgenia. METHODS: After understanding the characteristics of a patient's inferior one-third facial malformation through physical and cephalometric measurement, we correct the malformation of moderate or serious degree with osteotomy genioplasty. RESULTS: Eight patients received the operation and obtained good results. CONCLUSION: Understanding the characteristics of microgenia and choosing a rational method is the prerequisite for a good operative result.

Adult↗
PubMed2000

[A primary study on distribution and binding forms of arsenic in polluted crop seeds].

The distribution, binding form and processing removal of arsenic in rice and wheat seeds were studied. The result shows that the distribution of arsenic in seed parts was uneven, as concentration in rice seed was embryo > seed capsule > chaff > endosperm, and that in wheat seed was embryo > seed capsule > endosperm. Arsenic was mainly accumulated in endosperm, and mainly in the form of protein-binding. With the removal of chaff, coarse rice bran and fine rice bran in the processing, the content of arsenic decreased by 16.51%, 12.41% and 10.26%, respectively. Similarly, with the removal of coarse wheat bran and fine wheat bran, it decreased by 22.0% and 45.6%, respectively.

Arsenic↗
PubMed2000

[The effects of relieving space to stress distribution of mandibular implant-supported overdenture].

OBJECTIVE: To study the effects of relieving space to stress distribution of mandibular implant-supported overdenture under shocking loads. METHODS: 3-DFE method was used to make a comparative study of the effects of relieving space to stress distribution of the implant-supported overdenture under shocking loads. RESULTS: The application of stress relieving space can lower the stress peaks of the implants, periimplant tissue and the denture base. The highest stress of compression in lateral bone-implants interface reduced 52%. CONCLUSION: The application of stress relieving space can be helpful to protect implants, periimplant tissue and denture base.

Dental Prosthesis, Implant-Supported↗
PubMed2000

[Research of indole-3-acetic acid biosynthetic pathway of Klebsiella oxytoca SG-11 by HPLC and GC-MS].

The plant growth promoting bacteria are closely associated to plant. The bacteria are used to adhering to plant rhizoplane, promoting plant growth by fixing nitrogen from atmosphere, secreting stimulating substances or producing antagonistic to plant pathogens. It was indicated that the biological nitrogen fixation played an important role in plant growth promoting function. In fact, it was verified recently by overall research that IAA does it. Therefore research of IAA production and biosynthetic pathway of plant growth-promoting bacteria is much more important. The various ways of IAA production indicated the strong or weak promoting function of bacterium to plants in general. The purpose of this paper is to determine whether IAA exists in cultured medium of Klebsiella axytoca SG-11 and biosynthetic pathway of IAA, in order to opimize cultural conditions for IAA production. Klebsiella axytoca SG-11 is a plant growth promoting bacterium, isolated from rice rhizoplane, which can fix nitrogen. The supernatant of SG-11 cultured medium determined by HPLC showed that 47.4 mg/L of IAA existed in LB medium and 1.2 mg/L of IAA, in basal medium. IAA in metabolite was identified by GC/MS as well. The intermediate determination of tryptamine, indole-3-acetamide, tryptophol and indole-3-acetonitrile indirectly indicated that IAA was biosynthesized in a pathway of indole-3-pyruvic acid. Meanwhile, tryptophol in metabolite of SG-11 was verified by GC/MS. The direct intermediates of indole-3-pyruvic acid and indole-3-acetaldehyde in the pathway can not be determined, because both are unstable under normal condition. As reversible conversion existed between indole-3 pyruvic aldehyde and tryptophol, the presence of tryptophol also proved the pathway of indole-3-pyruvic acid in the synthesis of IAA by Klebsiella axytoca SG-11. The results laid basis for further research of plant growth-promoting function of the bacterium.

Chromatography, High Pressure Liquid↗
PubMed1999

Cadmium-induced apoptosis and changes in expression of p53, c-jun and MT-I genes in testes and ventral prostate of rats.

Apoptosis and a change in the expression of p53, c-jun and MT-I genes occurred in rats exposed to cadmium in a way known to cause carcinogenesis in testes and ventral prostate. In situ end labelling (ISEL), DNA electrophoresis, and RT-PCR methods were used in present study. Adult male Wistar rats were given a single (s.c.) injection of 0, 5, 10, or 20 micromol/kg CdCl2. Then 12, 48 or 96 h after administration of cadmium, animals were sacrificed. It was observed that cadmium markedly induced apoptosis in the testes at the dose of 5 micromol/kg while 10 and 20 micromol/kg cadmium caused more necrosis than apoptosis. Apoptosis in the ventral prostate was markedly induced by all the doses of cadmium and there was an obvious time- and dose-dependent relationship between apoptotic index (AI) and cadmium treatment. Far fewer apoptotic cells appeared in liver, compared to the testes and ventral prostate. p53 mRNA expression was clearly enhanced in the ventral prostate but clearly suppressed in the testes by cadmium exposure, and the time- and dose-effect was very clear. The expression level of p53 in the liver was not affected by cadmium treatment. Cadmium-induced overexpression of c-jun gene appeared at 12 h in the liver, but not until 96 h in the testes and ventral prostate. Although the MT-I gene was found to be expressed in all tissues, marked induction by cadmium of the expression of MT-I gene was only observed in the liver. These results indicate: (1) that apoptosis is an early mechanism of acute tissue damage by cadmium in the testes and ventral prostate; (2) that p53 and c-jun genes may be involved in cadmium-induced cytotoxicity (apoptosis) and related carcinogenicity in male reproductive tissues; and (3) that the enhanced expression of MT-I in the liver could protect this organ from cadmium-induced cytotoxicity (apoptosis) and carcinogenicity.

Animals↗
PubMed1999

A role for the proteasome in the light response of the timeless clock protein.

The cyclic expression of the period (PER) and timeless (TIM) proteins is critical for the molecular circadian feedback loop in Drosophila. The entrainment by light of the circadian clock is mediated by a reduction in TIM levels. To elucidate the mechanism of this process, the sensitivity of TIM regulation by light was tested in an in vitro assay with inhibitors of candidate proteolytic pathways. The data suggested that TIM is degraded through a ubiquitin-proteasome mechanism. In addition, in cultures from third-instar larvae, TIM degradation was blocked specifically by inhibitors of proteasome activity. Degradation appeared to be preceded by tyrosine phosphorylation. Finally, TIM was ubiquitinated in response to light in cultured cells.

Acetylcysteine↗
PubMed1999

MHC class II antigen processing in B cells: accelerated intracellular targeting of antigens.

Processing and presentation by Ag-specific B cells is initiated by Ag binding to the B cell Ag receptor (BCR). Cross-linking of the BCR by Ag results in a rapid targeting of the BCR and bound Ag to the MHC class II peptide loading compartment (IIPLC). This accelerated delivery of Ag may be essential in vivo during periods of rapid Ag-driven B cell expansion and T cell-dependent selection. Here, we use both immunoelectron microscopy and a nondisruptive protein chemical polymerization method to define the intracellular pathway of the targeting of Ags by the BCR. We show that following cross-linking, the BCR is rapidly transported through transferrin receptor-containing early endosomes to a LAMP-1+, beta-hexosaminadase+, multivesicular compartment that is an active site of peptide-class II complex assembly, containing both class II-invariant chain complexes in the process of invariant chain proteolytic removal as well as mature peptide-class II complexes. The BCR enters the class II-containing compartment as an intact mIg/Igalpha/Igbeta complex bound to Ag. The pathway by which the BCR targets Ag to the IIPLC appears not to be identical to that by which Ags taken up by fluid phase pinocytosis traffick, suggesting that the accelerated BCR pathway may be specialized and potentially independently regulated.

Animals↗
PubMed1999

Proteolytic release and nuclear translocation of Notch-1 are induced by presenilin-1 and impaired by pathogenic presenilin-1 mutations.

The Notch family of proteins consists of transmembrane receptors that play a critical role in the determination of cell fate. Genetic studies in Caenorhabditis elegans suggest that the presenilin proteins, which are associated with familial Alzheimer's disease, regulate Notch signaling. Here we show that proteolytic release of the Notch-1 intracellular domain (NICD), an essential step in the activation of Notch signaling, is markedly reduced in presenilin-1 (PS1)-deficient cells and is restored by PS1 expression. Nuclear translocation of the NICD is also markedly reduced in PS1-deficient cells, resulting in reduced transcriptional activation. Mutations in PS1 that are associated with familial Alzheimer's disease impair the ability of PS1 to induce proteolytic release of the NICD and nuclear translocation of the cleaved protein. These results suggest that PS1 plays a central role in the proteolytic activation of the Notch-1-signaling pathway and that this function is impaired by pathogenic PS1 mutations. Thus, dysregulation of proteolytic function may underlie the mechanism by which presenilin mutations cause Alzheimer's disease.

Alzheimer Disease↗
PubMed1999

Ig alpha and Ig beta are required for efficient trafficking to late endosomes and to enhance antigen presentation.

The B cell Ag receptor (BCR) is a multimeric complex, containing Ig alpha and Ig beta, capable of internalizing and delivering specific Ags to specialized late endosomes, where they are processed into peptides for loading onto MHC class II molecules. By this mechanism, the presentation of receptor-selected epitopes to T cells is enhanced by several orders of magnitude. Previously, it has been reported that, under some circumstances, either Ig alpha or Ig beta can facilitate the presentation of Ags. However, we now demonstrate that if these Ags are at low concentrations and temporally restricted, both Ig alpha and Ig beta are required. When compared with the BCR, chimeric complexes containing either chain alone were internalized but failed to access the MHC class II-enriched compartment (MIIC) or induce the aggregation and fusion of its constituent vesicles. Furthermore, Ig alpha/Ig beta complexes in which the immunoreceptor tyrosine-based activation motif tyrosines of Ig alpha were mutated were also incapable of accessing the MIIC or of facilitating the presentation of Ag. These data indicate that both Ig alpha and Ig beta contribute signaling, and possibly other functions, to the BCR that are necessary and sufficient to reconstitute the trafficking and Ag-processing enhancing capacities of the intact receptor complex.

Animals↗
PubMed1999

Trafficking of the Igalpha/Igbeta heterodimer with membrane Ig and bound antigen to the major histocompatibility complex class II peptide-loading compartment.

The binding of antigen to the B cell antigen receptor (BCR) initiates two major cellular events. First, upon cross-linking by antigen, the BCR induces signal transduction cascades leading to the transcription of a number of genes associated with B cell activation. Second, the BCR internalizes and delivers antigens to processing compartments, where processed antigenic peptides are loaded onto major histocompatibility complex (MHC) class II molecules for presentation to T helper cells. The BCR consists of membrane Ig (mIg) and Igalpha/Igbeta heterodimer (Igalpha/Igbeta). The Igalpha/Igbeta, the signal transducing component of the BCR, has been indicated to play a role in antigen processing. In order to understand the function of the Igalpha/Igbeta in antigen transport, we studied the intracellular trafficking pathway of the Igalpha/Igbeta. We show that in the absence of antigen binding, the Igalpha/Igbeta constitutively traffics with mIg from the plasma membrane, through the early endosomes, to the MHC class II peptide-loading compartment. Cross-linking the BCR does not alter the trafficking pathway; however, it accelerates the transport of the Igalpha/Igbeta to the MHC class II peptide-loading compartment. This suggests that the Igalpha/Igbeta heterodimer is involved in BCR-mediated antigen transport through the entire antigen transport pathway.

Dimerization↗
PubMed1999

[Identification of mutations in the phenylalanine hydroxylase gene and exon 5 novel mutation Y166X(C-->G) in Yunnan].

OBJECTIVE: To identify the mutations of the phenylalanine hydroxylase gene in Yunnan so as to enhance the gene diagnosis of classical phenylketonuria (PKU) in that south-western province of China. METHODS: Exons 4,5,6,7,10,11 and 12 of the phenylalanine hydroxylase(PAH) were analyzed in 13/14 children affected with classical PKU from Yunnan by using PCR-single strand conformation polymorphism (PCR-SSCP),PCR-ASO dot blot hybridization,allele specific polymerase chain reaction(ASPCR) and PCR-direct sequencing. RESULTS: Five missense mutations, i.e. R243Q. (5/26), Y204C(3/28), G247V(1/26),R413P(2/28) and T418P(1/28);three nonsense mutations,i.e. Y166X(C-->G)(2/26),W326X(1/28) and Y356X(2/26);and one silent mutation(V399V)(2/26) were identified. The nonsense mutation Y166X(C-->G) should be a novel mutation as compared with the PAH Mutation Database. CONCLUSION: Five kinds of popular PAH gene mutation (R243Q,Y204C,V399V,Y356X and R413P) identified in the people of Yunnan are similar to those in the northern people, but such characteristic is different from that in the southern people. This finding will enhance the efficacy in gene diagnosis of PKU and will be of reference value for studies of population and regional difference in the pattern of PAH mutation distribution.

Child↗
PubMed1999

Retinal neovascularization is suppressed with a matrix metalloproteinase inhibitor.

OBJECTIVES: To determine the role of extracellular proteinases in ischemia-induced retinal neovascularization in an animal model and to examine the effect of proteinase inhibitors on retinal neovascularization. METHODS: Retinal neovascularization was induced in newborn mice exposed to 75% oxygen for 5 days, followed by room air. Retinal extracts underwent zymographic analysis to measure the activity of urokinase and matrix metalloproteinases (MMPs). Some animals under the same conditions also received intraperitoneal injections of an MMP inhibitor. Histological analysis was done to quantitate the neovascular response in these animals. RESULTS: Levels of urokinase and MMPs (MMP-2 and MMP-9) in retinas were significantly increased in animals with induced retinal neovascularization. Neovascularization was significantly inhibited with intraperitoneal administration of an MMP inhibitor. CONCLUSION: Systemic inhibition of MMPs may have therapeutic potential in preventing retinopathy associated with retinal neovascularization. CLINICAL RELEVANCE: Because up-regulation and activation of proteinases represents a final common pathway in the process of retinal neovascularization, pharmacological intervention of this pathway may be an alternative therapeutic approach to proliferative retinopathy.

Animals↗
PubMed1999

Hepatocyte growth factor expression in the developing myocardium: evidence for a role in the regulation of the mesenchymal cell phenotype and urokinase expression.

During development of the heart, the endocardium of the developing cushion tissue transforms into mesenchymal cells that rapidly invade the underlying extracellular matrix. This invasive process, along with subsequent proliferation and differentiation of the mesenchyme, are essential for the normal formation of valvular and septal structures. Several factors have been identified that appear to initiate and/or control this transformation process, including the growth factor TGF-beta. In these studies we have investigated whether hepatocyte growth factor/scatter factor (HGF/SF) may also be involved in some aspects of this transformation process. Using an immunohistochemical approach we have detected a spatially restricted localization of HGF/SF to the myocardial cells of the cushion tissue. HGF was detected in extracts of the developing heart, and the presence of the active form correlated with the onset of the transformation process and the elevation of urokinase activity. The endocardial-derived mesenchymal cells of the cushion tissue were found to express the c-met HGF receptor. Isolated endocardial cells responded to the addition of HGF with increases in motility, proliferation, and urokinase production. The results from these studies suggest that HGF may function as a myocardial-derived mediator of the epithelial-mesenchymal transformation by inducing and/or maintaining the mesenchymal cell phenotype. The increase in urokinase expression by the cushion tissue cells, in response to HGF, may facilitate the invasive abilities of these cells and also provide a means of maintaining high levels of active HGF required for the stimulation of cell proliferation and migration.

Animals↗
PubMed1999

Trichodinid ectoparasites (Ciliophora: Peritrichida) from the gills of cultured marine fishes in China, with the description of Trichodinella lomi n. sp.

Three species of cultured percoids, each heavily infested by trichodinid ectoparasites, were examined from over-wintering pools in Qingdao, China during the winter of 1995. A total of five species of trichodinids belonging to three genera, Trichodinella Sramek-Husek, 1953, Dipartiella Shtein, 1961 and Trichodina Ehrenberg, 1838 were recorded. One new species, Trichodinella lomi n. sp., is described, the denticle of which is characterised by its acutely triangular blade, comma-like central part and inconspicuous ray. The morphology of Trichodina murmanica Poljansky, 1955 was re-investigated. Three other little-known species are redescribed: Dipartiella simplex (Raabe, 1959) Shtein, 1961, Trichodina japonica Imai, Miyazaki & Nomura, 1991 and T. domerguei (Wallengren, 1897).

Animals↗
PubMed1999

Trichodinid ectoparasites (Ciliophora: Peritrichida) from the gills of mariculture molluscs in China, with the descriptions of four news species of Trichodina Ehrenberg, 1838.

Four new species of the genus Trichodina, found on gills of marine molluscs from aquaculture beds off the coast of Qingdao (Tsingao), China, are described: T. chlamydis n. sp. from Azumapecten (Chlamys)farreri (Pectinidae), T. sinonovaculae n. sp. from Sinonovacula constricta (Solenidae), T. liana n. sp. from Solen (Plectosolen) gracilis (Solenidae) and T. meretricis n. sp. from Meretrix meretrix (Veneridae). The descriptions presented here include morphometric data obtained from examinations of specimens prepared using the wet silver nitrate and protargol-impregnation techniques. Comparisons with closely related species are provided for each of the four.

Animals↗
PubMed1999

[Changes of free radicals in fetal rats brain and liver following intrauterine fetal distress].

OBJECTIVE: To analysis the effect of superoxide dismutase (SOD) and malondialdehyde (MDA) on different organs in intrauterine fetal distress. METHODS: The times of clamping uterine artery in A, B, C groups were 5, 10, 20 minites respectively. By clamping the matenal uterine vessels, we made the model of fetal rat distress. Slam group (13 pups) was used as control. After clamping 10 minutes, Group D (11 pups) was reperfused 5 minutes, and E (8 pups) 20 minutes. We measured the level of SOD and MDA in fetal brains and livers. RESULTS: The activity of cerebral SOD in group B and C decreased significantly than that of control (P < 0.05, P < 0.01). MDA in group C increased significantly than that of control (P < 0.05). As for liver, only SOD in group C decreased significantly (P < 0.05). In that of reperfusion group, only in group E, cerebral SOD and MDA changed significantly (P < 0.01, < 0.05), livers SOD decreased significantly (P < 0.05). CONCLUSION: After severe intrauterine fetal distress, changes of free radicals occurred in brains firstly, which provides the proof of early treatment for neonatal hypoxia ischemia brain damage.

Animals↗