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Biomedical subjects

Y Jiang

Publications and source records attributed to Y Jiang.

At least 577 records · Page 32Linked to original sources
PubMed1995

[Expression of adhesion molecules on lymphocyte in patients with systemic lupus erythematosus].

Peripheral blood lymphocyte phenotype (CD3, CD4, CD8, CD20, CD45RA and CD45RO) and adhesion molecule phenotype (CD11a/LFA-1 alpha, CD18/LFA-1 beta and CD54/ICAM-1) were investigated in 35 patients with systemic lupus erythematosus (SLE) by using flow cytometric analysis and dual immunofluorescence staining method. Results demonstrated increase in CD8+ cell and decrease in CD4+ cell, CD4+/CD8+, and CD4+/CD45RA+ cell, as well as decrease in expression of CD11a and CD18 on CD4+ cell surface, Expression of CD11a and CD18 on CD8+ cell, and CD54 on CD20+ cell increased, Moreover, increase in CD18 on CD8+ cell correlated inversely with decrease in CD4+ CD45RA+ cell (P < 0.05) and positively with increase in CD54 on CD20+ cell (P < 0.01). These data suggest that adhesion molecule LFA-1 and ICAM-1 may play an important role in the pathogenesis of SLE.

Adolescent↗
PubMed1995

An evaluation on smoking-induced health costs in China (1988-1989).

A study on smoking-attributable health economic costs in China was conducted from 1988-1992, in which three major categories of chronic diseases, diseases of cancer, diseases of circulatory system, and diseases of respiratory system were included. A prevalence-based method which estimated the cumulative effect of cigarette smoking during the past 20-30 years was used. The results show that in 1989, the total smoking-attributable economic costs to health sectors in China were about 27.1 billion of Chinese Yuan, including about 7 billion Yuan in direct medical costs and 20 billion Yuan in indirect costs, which include indirect morbidity costs and indirect mortality costs. The relatively low direct costs reflected the low medical costs at hospitals in China at that time. And the high proportion of indirect costs relative to the total costs shows the high potential years of life lost due to cigarette smoking. The results also show the heavier health burden in urban areas than in rural areas, reflecting the worse situation in urban China at nowadays. But if considering that almost 80% of the Chinese are rural farmers with the higher smoking prevalence and relatively shorter history of manufactured cigarette smoking than their urban counterparts, the very frightful situation due to cigarette smoking would be for China in the next century.

Cardiovascular Diseases↗
PubMed1995

[A preliminary observation of preventive and blocking effect of Gynostemma pentaphyllum (Thunb) Makino on esophageal cancer in rats].

Gynostemma pentaphyllum (Thunb) Makino is a kind of natural plant growing in the southern provinces of China. In this experiment, rats were given drinks of 2% Gynostemma Pentaphyllum (Thunb) makino aqua boiled solution freely for 2 weeks before administration of carcinogen. Subsequently, the rats were injected with carcinogen (MANA) for 18 weeks and were sacrificed at intervals. The result showed that the number of cases of esophageal epithelial papilloma, the average number of tumor and the incidence of esophageal cancer in the experimental group were lower than those in the control group (MANA only), though no statistical significant difference was found. The initiation of cancer was delayed for 6 weeks. These indicated that Gynostemma Pentaphllum Makino might have some preventive and blocking effect on esophageal cancer in rats.

Animals↗
PubMed1995

[Gastrointestinal smooth muscle tumors: a study of DNA content and the association with clinicopathology].

Quantitative analysis of DNA content and ploidy pattern was performed in 84 cases of smooth muscle tumors of the gastrointestinal tract by flow cytometry, and the results were correlated with histopathologic features. The aneuploid rate was found to be 0, 50%, 75%, 92.8% and 100% respectively in the tumors with mitotic figures of 0,1, 2-4, 5-9, or over 10/10HPF (P < 0.005), as to be 3.2%, 60%, 95.8% and 100% in tumors with zero, mild, moderate or severe cellular atypia (P < 0.005). There were no aneuploidy in the 30 cases of leiomyomas, but all 40 cases of leiomyosarcomas were aneuploidy, while in the 14 potentially malignant smooth muscle tumors, there were 4 cases of aneuploidy (P < 0.01). The aneuploid rate was significantly higher in tumors with contiguous organ inveasion or distant metastasis (79.5%), and in tumors of large size (64.5%) as well as in tumors with center necrosis (68.3%). 5 year survival rate in patients with aneuploid tumors (41.6%) was significantly lower than those with diploid tumors (96%) (P < 0.005). The results suggested that DNA content and ploidy pattern be used as an objective parameter to distinguish malignants from benigns and predict the prognosis of patients with gastrointestinal smooth muscle tumors.

Adolescent↗
PubMed1995

[Acoustic characteristics of external auditory meatus after tympanoplasty with open mastoid reconstruction].

This study investigated the effects of down-wall tympanoplasty (open technique included skeletonizing of mastoid) upon external auditory meatus resonance characteristics. The probe tube microphone measurement was performed twice pre and post operatively. The resonance frequency of external auditory meatus remained constant, but the peak amplitude was increased by 0.83dB SPL (P < 0.05). The results indicated that a tympanoplasty with standard open techniques did not affect the normal external auditory meatus resonance characteristics.

Acoustics↗
PubMed1995

[A comparison of attachment rates between SF6 and silicone oil tamponades following vitrectomy for treatment of complicated retinal detachment].

In this study, 215 eyes with rhegmatogenous retinal detachment and proliferative vitreoretinopathy (PVR) including giant tears, macular holes, perforating injury and traction caused by retinal vascular diseases were treated by vitrectomy and SF6 or silicone oil. The anatomic attachment rates were compared between gas and silicone oil groups in non-vitrectomized eyes and previously vitrectomized eyes, respectively. Both gas and silicone oil groups showed higher attachment rates in stage C of PVR, giant tears with PVR less than stage C2 and macular holes. The gas group showed lower attachment rates in cases with stage D of PVR, giant tear larger than 180 degrees or with PVR C3 or greater than C3, after perforating injury and traction-rhegmatogenous retinal detachment, while silicone oil group showed better attachment rates. The choice of tamponades should be based on different indications.

Adolescent↗
PubMed1994

Ypt1p implicated in v-SNARE activation.

Synaptobrevin-like membrane proteins that reside on transport vesicles, called the vesicle SNARE (v-SNARE), play a key role in ensuring that a vesicle targets and fuses with its correct acceptor compartment. Here we show that Bos1p, the v-SNARE of yeast endoplasmic reticulum-to-Golgi transport vesicles, pairs with another integral membrane protein of similar topology (Sec22p) on vesicles. This pairing, which appears to require functional Ypt1p (Rab in mammalian cells), may aid the activity of Bos1p on this compartment. These findings suggest that Rabs regulate the specificity of membrane fusion by selectively activating the v-SNARE on carrier vesicles. Because the v-SNARE resides on more than one membrane, such a regulated activation step may be necessary to prevent the premature fusion of donor and acceptor compartments.

Biological Transport↗
PubMed1994

RNA polymerase II phosphorylation: uncoupling from GAL4-VP16 directed open complex formation and transcription in a reconstituted system.

An activated transcription system was constructed using substantially purified liver factors, Hela TFIID and GAL4-VP16. The system was used to study the relationship between RNA polymerase II large subunit phosphorylation and other ATP-dependent processes occurring during activated transcription. When C-terminal domain (CTD) kinase activity was inhibited, activator dependent open promoter complex formation proceeded normally. These open complexes could function to produce RNA in the absence of CTD phosphorylation, although the level of RNA produced was changed somewhat. The results demonstrate that RNA polymerase II CTD phosphorylation is not generally required for the formation of activator-dependent, functional open promoter complexes. Taken together with prior results the experiments suggest that a requirement for CTD phosphorylation may be situation-dependent and thus serve a regulatory function.

Adenosine Triphosphate↗
PubMed1994

Alternatively spliced mRNAs encoding soluble isoforms of the erythropoietin receptor in murine cell lines and bone marrow.

32D Epo and 32D GM cells are subclones of the murine 32D cell line which are selectively dependent for proliferation and survival on erythropoietin (Epo) or granulocyte/macrophage colony-stimulating factor (GM-CSF), respectively. 32D GM cells were previously shown to express significant levels of the Epo receptor mRNA and protein which was retained intracellularly and did not appear on the cell surface. We have now analyzed the EpoR mRNA from the 32D GM line, using PCR followed by direct sequencing. Several alternatively spliced products were detected. In some molecules, intron 5 (I5) or part of I6 or both were retained. Retention of I5 results in a mRNA potentially encoding an almost complete extracellular domain, while retention of I6 gives rise to a mRNA encoding the complete extracellular and transmembrane domains. A different type of splicing results in the loss of exon 5 (E5), giving rise to a sequence encoding a truncated extracellular domain. These alternatively spliced sequences are differentially represented in 32D Epo versus 32D GM cells. All are additionally present in normal bone marrow cells. Apart from these alternatively spliced EpoR RNAs, no other abnormalities were detected in EpoR RNA from 32D GM cells that could account for the intracellular retention of EpoR in the non-erythroid subclones of 32D.

Alternative Splicing↗
PubMed1994

Regulation of human DNA polymerase delta during the cell cycle.

The expression of polymerase delta (pol delta) during the cell cycle was studied in Molt 4 cells separated by counter-flow centrifugal elutriation. Northern blotting showed that pol delta mRNA levels increased by 3-fold at the G1/S border. Levels of pol delta protein determined by Western blotting also peaked at the G1/S border with qualitatively similar changes as the mRNA levels. Thus, pol delta gene expression appears to be regulated during the cell cycle at the transcriptional level. The mRNA half-life for pol delta was determined to be about 8 h and the protein half-life about 10 h. Parallel examination of the expression of proliferating cell nuclear antigen showed that the mRNA levels also increased about 2-fold at the G1/S border, while the protein levels of proliferating cell nuclear antigen increased steadily through the whole cell cycle period, and remained high at G2/M. Analysis of pol alpha expression showed qualitatively similar behavior as pol delta, but the magnitude of the changes were higher. Pulse labeling of cells metabolically arrested in G1,S, or G2/M with 32Pi showed that pol delta is a phosphoprotein and that it is most actively phosphorylated during the S phase.

Cell Cycle↗
PubMed1994

Chemical modification of the hydroxylase of soluble methane monooxygenase gives one form of the protein with significantly increased thermostability and another that functions well in organic solvents.

Proteolysis of the hydroxylase component of soluble methane monooxygenase (MMO) with trypsin yielded a protein which retained 50% activity in a standard MMO assay. In an H2O2-driven assay, in which H2O2 replaced two of the protein components, NADH and O2 used in the standard assay, the proteolysed hydroxylase retained full activity for ethane, propane and propene, but had a 2-3-fold increase with methane as substrate. Several crosslinking reagents have been tested for their ability to stabilise the proteolysed form of the hydroxylase. Using polyoxyethylene bis(imidazolyl carbonyl) (M(r) 3350) as the crosslinking agent, increased thermostability of the hydroxylase was observed. Activated methoxypolyethylene glycol (M(r) 5000) was used to modify the hydroxylase which was now soluble in organic solvents as well as water and could be activated by H2O2. The glycol-modified hydroxylase functioned well in organic solvents in the catalysis of propene oxidation.

Enzyme Stability↗
PubMed1994

A study on superoxide dismutase activity of some model compounds.

The synthesis and characteristics of a binuclear ligand N,N,N',N'-tetrakis (2'-benzimidazolyl methyl)-1,4-diethylene amino glycol ether (EGTB) and its series of coordination compounds containing copper(II), iron(III), and manganese(II) with and without exogenous bridging ligand which was imidazolate ion (Im-), bipyridine (bpy), or 1,10-phenanthroline (phen) are reported. Depending on the redox potentials by cyclic voltammetry, the coordination compounds can act as catalysts for the dismutation of superoxide radicals (O2-). The detection of the rate constant of the reaction of superoxide ion with nitroblue tetrazolium (NBT) which is inhibited by superoxide dismutase (SOD) and its model compounds of the EGTB system has been performed by a modified illumination method. The rate constants kQ of the catalytic dismutation have been obtained.

Copper↗
PubMed1994

Molecular determinants of bioactivity of the Saccharomyces cerevisiae lipopeptide mating pheromone.

The a-factor of Saccharomyces cerevisiae (YIIKGVF-WDPAC(Farnesyl)-OCH3) is a peptide pheromone in which post-translational modification with a farnesyl isoprenoid and carboxyl methyl group is required for export and bioactivity. Truncated and carboxyl-terminal modified analogs of the a-factor were synthesized in order to determine the effect of such modifications on bioactivity. Bioactivity studies on carboxyl-terminal analogs in which the chirality, the cysteine thioether, and the carboxyl ester were varied in an attempt to study the influence of topology on a-factor activity indicate that the hydrophobicity conferred by the farnesyl moiety and not its specific spatial orientation is a key determinant of a-factor potency. Analyses on truncated a-factors suggest that sequential removal of NH2-terminal residues leads to a gradient of potency loss, with some amino acids exhibiting a slightly greater contribution to bioactivity than others. Random oligonucleotide-targeted mutagenesis of the gene encoding a-factor was coupled to a biological screen to identify altered a-factor peptides which are secreted yet exhibit a loss of a-factor bioactivity. Transformants exhibiting this phenotype were examined to identify codon changes presumably responsible for the altered phenotype, thus indicating residues that may contribute significantly to a-factor bioactivity.

Amino Acid Sequence↗
PubMed1994

DNA polymerase delta is involved in the cellular response to UV damage in human cells.

We have used antibodies specific for either polymerase delta (pol delta) or its accessory protein, proliferating cell nuclear antigen (PCNA), to demonstrate that they can markedly inhibit the capacity of HeLa nuclear extracts to effect repair of UV-damaged plasmid DNA. This provides the first unambiguous evidence for the involvement of pol delta in DNA repair synthesis. The mRNA levels of both pol delta and PCNA were significantly stimulated subsequent to UV irradiation of cultured cells, providing the first evidence that the cellular response to UV damage may involve regulation of pol delta and PCNA at the gene level. Thus, DNA polymerase delta and its accessory proteins, in addition to their function in replicative DNA synthesis, also function in DNA repair synthesis.

Catalysis↗
PubMed1994

Identification of yeast component A: reconstitution of the geranylgeranyltransferase that modifies Ypt1p and Sec4p.

Members of a large family of small GTP-binding proteins, termed Rabs in mammalian cells or Ypt and Sec4 in yeast, regulate vesicular traffic in all eukaryotic cells. These proteins are able to bind to membranes because they are modified by the type II geranylgeranyltransferase (GGTase-II), a multisubunit complex. Component A, encoded by the choroideremia gene in humans, is an escort protein that brings Rabs to component B, the catalytic alpha/beta heterodimer. Mutations in the catalytic subunits of the yeast GGTase-II (Bet2p/Mad2p) disrupt the membrane attachment of Ypt1p and Sec4p and this in turn blocks membrane traffic. In mammalian cells, deletions in choroideremia lead only to retinal degeneration, even though GGTase-II activity is defective. The yeast MRS6 gene encodes a protein that is approximately 30% identical to the choroideremia gene product. Here we show that the addition of recombinant Mrs6p to bacterially expressed Bet2p (beta subunit) and Mad2p (alpha subunit) reconstitutes GGTase-II activity in vitro, demonstrating that Mrs6p is yeast component A. Like Bet2p and Mad2p, Mrs6p is required for the membrane attachment of Ypt1p and Sec4p in vivo. In contrast to what has been observed before for the loss of function of the choroideremia gene, the depletion of Mrs6p from yeast cells blocks vesicular transport. Thus, these findings suggest that there is one essential escort protein in yeast, while more than one may exist in mammalian cells.

Alkyl and Aryl Transferases↗
PubMed1994

RNA polymerase binding using a strongly acidic hydrophobic-repeat region of sigma 54.

sigma 54 is a rare bacterial protein that substitutes for sigma 70 in the case of Escherichia coli genes transcribed by certain activators with enhancer protein-like properties. It contains a strongly acidic region of previously unknown function. Gel mobility-shift assays using sigma 54 deletion mutants show that this region is essential for sigma 54 to bind the core RNA polymerase and recruit it to the promoter. Multiple-point mutational analysis shows that the acidic amino acids and overlapping periodic hydrophobic amino acids are necessary for this binding. Related sequences are not found within the core binding determinant of sigma 70, which binds the same core RNA polymerase. This comparison suggests that the core RNA polymerase interacts differently with the two sigma factors, likely contributing to the critical differences in transcription mechanism in the two cases.

Amino Acid Sequence↗