[Cloning of cDNA encoding asparagine peptidase of Chinese strain of Schistosoma japonicum and its expression in BALB/c mice].
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Animals↗
Biomedical subjects
Y Shi
Publications and source records attributed to Y Shi.
[Distribution of human hsp90 beta gene in active chromatin upon heat shock].
OBJECTIVE: To study the distribution of human hsp90 beta gene in active chromatin of Jurkat cells subjected to heat shock. METHODS: Active and inactive chromatin were isolated by using organomercurial affinity chromatography from Jurkat cells with or without heat shock. Slot-blot hybridization was then carried out with human hsp90 beta cDNA probe. And the efficiency of mRNA expression was studied by Northern blot hybridization. RESULTS: The content of the hsp90 beta gene distributed in the active chromatin was increased upon heat shock which was comparable with the highly efficient mRNA expression induced by the same treatment. CONCLUSIONS: The results suggested chromatin activity was a prerequisite for heat shock induction of hsp90 beta gene.
Chromatin↗
[The development of model DYC-I multi-purpose device for lumbar vertebra puncture].
A multi-purpose device for lumbar Vertebra puncture, which is ablete obtain cerebrospinal fluid (csf) and to determine the intracranial pressure, is presented here. This device has the functions of avoiding blindness of puncture, measuring pressure hermetically, liquid crystal display and controlling the flow of CSF.
Equipment Design↗
[Preliminary study on relationship between different viral pathogenesis and disease prognosis in patients with severe viral hepatitis].
OBJECTIVE: To study the relationship between different viral pathogenesis and disease prognosis in severe viral hepatitis. METHODS: Different viral pathogenesis of 87 dead and live cases with severe viral hepatitis were compared. RESULTS: Total mortality of 87 patients with severe hepatitis was 74.71% (65/87), total prevalence of HBV infection alone in these patients was 41.38% (36/87). The detection rates of HBV infection alone and superinfection of different hepatitis viruses in 68 patients with chronic severe hepatitis (CSH) were 41.18% (28/68) and 58.82% (40/68) respectively. The prevalences of superinfection of HBV and HEV or HAV and superinfection of HBV and CMV in patients with CSH were 27.94% (19/68) and 10.29 (7/68) respectively. The mortality of superinfection of HBV and CMV (85.71%) was the highest, followed by HBV infection alone (77.78%). In addition, the prevalence and mortality of HBV infection alone in 19 patients with acute or subacute severe hepatitis was the highest. CONCLUSION: HBV, HEV or HAV infection alone was the main viral pathogenesis of severe hepatitis. Superinfection of different viruses in patients with CSH was the most common viral infection type. An unpromising prognosis of superinfection of HBV and CMV in CSH is noted.
Adolescent↗
[A review of the study on swainsonine--toxic elements of locoweed].
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Adjuvants, Immunologic↗
[Detection of low temperature rheologic behavior of lubricating oil by FTIR].
The composition and structure of lubricating oil expressed by FTIR were used for its characterization. Artificial nervous network was used as a mathematical model. CCS-15C viscosity of base oil was forecasted and good result was obtained. The result has shown that the artificial nervous network is an effective mathematical model for studying the relation between the composition and structure of lubricating oil and its performance.
English Abstract↗
[Spectrophotometric determination of iron using eriochrome cyanine R as extractant with phase-separation].
Spectrophotometric determination of iron by using eriochrome cyanine R as extractant and color-developing agent in organic solvents was studied. The complex was extracted by PEG phase from the water solutions of pH4.5-6.5 (NaAc-HAc). The maximum absorption of the complex is at 560 nm and the molar absorptivity is 5.36 x 10(4) L x mol(-1) x cm(-1). Beers law was obeyed in the range of 0-40 microg Fe. Iron and eriochrome cyanine R formed a stable complex with a molar ratio of 1:2. The proposed method has been applied to the determination of copper in aluminium alloys with satisfactory results.
Benzenesulfonates↗
Solution structure of a fragment of the dimerization domain of DP-1 determined by 1H-nuclear magnetic resonance and distance geometry.
The structure of a synthesized peptide with the sequence of NHILPNESAYDQKNIRRRVYDALNVLMAMNIISK that corresponds to residues 151-184 of transcription factor DP-1 (Girling et al., Nature 362 (1993) 83-87) was determined by 1H-nuclear magnetic resonance in water and 40% d3-trifluoroethanol/water, respectively. Nuclear Overhauser effect cross peaks, alphaH chemical shifts and J-coupling constants of alphaH-NH show that the peptide consists a helix from Ser-8 to Ser-33 in solution. Fifty structures were constructed with 288 upper distance limits and 21 angle constraints by DIANA (Guntert et al., J. Mol. Biol. 217 (1991) 517-530). Although the N-terminal of the peptide exhibits a random conformation, the 20 best structures show a root mean square deviation of 0.89+/-0.36 A for backbone atoms and 1.80+/-0.34 A for heavy atoms from residue Ser-8 to Ser-33. This result supports the proposal that DP-1 and E2F-1 may dimerize with a coiled-coil type interaction.
Amino Acid Sequence↗
Methylation of the androgen receptor promoter CpG island is associated with loss of androgen receptor expression in prostate cancer cells.
Androgen-independent metastatic prostate cancer is characterized by a heterogeneous loss of androgen receptor (AR) expression among tumor cells. In this study, we evaluate DNA hypermethylation as a potential transcriptional regulatory mechanism in AR-negative prostate cancer cell lines. Nucleotide sequence analysis demonstrates an approximately 15-kb CpG island in the AR gene that encompasses the transcription start site and exon 1. Using Southern blotting with methylation-sensitive restriction enzymes and methylation-specific PCR, we find aberrant methylation in the AR expression-negative cell lines Du145, DuPro, TSU-PR1, and PPC1. Incomplete methylation in the AR CpG island is also seen in normal female breast and ovarian tissues consistent with the inactivation of one X chromosome by hypermethylation. In contrast, prostate cancer cell lines LNCaP and PC3 express AR and are unmethylated. Normal prostate epithelial cell strains demonstrate no methylation. Exposure of AR-negative prostate cancer cell lines to 5-aza-2' deoxycytidine, a demethylating agent, induces the reexpression of AR RNA in DuPro and TSU-PR1. This reexpression is associated with a demethylation of this region. Prostate-specific antigen, an androgen-responsive gene, is also specifically induced in these lines after AR reexpression. Therefore, in vitro DNA methylation of the 5' CpG AR island may be associated with the loss of AR expression. Furthermore, our results demonstrate that treatment with demethylating agents may engender the reexpression and function of the androgen receptor in AR-negative cell lines.
CpG Islands↗
Mapping of the human PAWR (par-4) gene to chromosome 12q21.
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Apoptosis Regulatory Proteins↗
Solution structure of a fragment of the dimerization domain of E2F-1 determined by circular dichroism, 1H nuclear magnetic resonance and distance geometry.
The structure of a synthesized peptide with the sequence GVVDLNWAAEVLKVQKRRIYDITNVLEGIQ which corresponds to residues 149-178 of transcription factor E2F-1 was determined by 1H nuclear magnetic resonance in 40% d3-TFE/water. NOE cross peaks and alphaH chemical shifts indicate that the peptide consists of a helix from Ala-8 to Leu-26 in this solution. Circular dichroism measurements confirm the presence of nearly 45% helix in TFE/water solution but show no evidence of helicity in water solution of this peptide. Fifty structures were constructed with 329 upper distance limits by DIANA. The 20 best conformers show a RMSD of 0.78 A for backbone atoms and 1.78 A for heavy atoms from residue Ala-8 to Leu-26. This result, together with our previous work on the solution structure of a fragment of DP-1, supports the proposal that E2F-1 and DP-1 may dimerize with a coiled-coil type interaction.
Amino Acid Sequence↗
Fungal metabolite FR901228 inhibits c-Myc and Fas ligand expression.
Activation of T lymphocytes often leads to cellular activation, production of cytokines, entry into cell cycle, and expression of Fas (CD95) and Fas ligand (FasL). Although it is well established that the interaction of Fas and FasL results in apoptosis, mechanisms for regulated expression of Fas and FasL are unclear. Our previous work with antisense oligodeoxynucleotides suggested that the protooncogene c-myc is obligatory for activation-induced apoptosis. To study the relationship between c-myc and the Fas/FasL expression, we employed the antisense method and a newly identified fungal metabolite, FR901228, which has been shown to specifically inhibit expression of c-myc in fibroblasts. We found that FR901228 could effectively block activation-induced apoptosis in T cell hybridomas and this was correlated with its specific inhibition of c-myc expression. Both FR901228 and antisense oligodeoxynucleotide to c-myc had similar effect in inhibiting FasL expression. These treatments did not affect activation-induced production of IL-2, nor the expression of Fas. In addition, FR901228 inhibited the expression of FasL in 3T3 fibroblasts, but not these transfected with c-myc, supporting a specific role of c-myc in this process. Thus, c-Myc plays a fundamental role in the regulation of the expression of FasL, but not Fas and IL-2. Our data further defined the requirement of c-Myc in activation-induced apoptosis in T cells.
3T3 Cells↗
Crystal structure of a Smad MH1 domain bound to DNA: insights on DNA binding in TGF-beta signaling.
The Smad family of proteins, which are frequently targeted by tumorigenic mutations in cancer, mediate TGF-beta signaling from cell membrane to nucleus. The crystal structure of a Smad3 MH1 domain bound to an optimal DNA sequence determined at 2.8 A resolution reveals a novel DNA-binding motif. In the crystals, base-specific DNA recognition is provided exclusively by a conserved 11-residue beta hairpin that is embedded in the major groove of DNA. A surface loop region, to which tumorigenic mutations map, has been identified as a functional surface important for Smad activity. This structure establishes a framework for understanding how Smad proteins may act in concert with other transcription factors in the regulation of TGF-beta-responsive genes.
Amino Acid Sequence↗
Protein kinase C regulates Fas (CD95/APO-1) expression.
Fas (CD95/APO-1) is a transmembrane protein of the TNF/neuron growth factor receptor family. Ligation of Fas by specific Abs or Fas ligand (FasL/CD95 ligand) induces rapid apoptotic cell death in a variety of cell types. Despite progress in understanding the death signals transduced from Fas, very little is known with regard to the mechanisms by which Fas expression is regulated. Using our previously established murine T cell hybridoma model A1.1, we show that specific protein kinase C (PKC) inhibitors could block activation-induced Fas expression and apoptosis. The activation of PKC with PMA or 1-oleoyl-2-acetyl-sn-glycerol could mimic the TCR signal by inducing the expression of Fas but not FasL. PKC-dependent Fas expression was also observed in several murine and human tumor cell lines. Since the inhibition of Ca2+ redistribution by an inhibitor of intracellular Ca2+ mobilization, 8-(diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride, inhibited TCR-induced FasL but not Fas, the expression of Fas appears to be independent of Ca2+ mobilization. Significantly, expression of the newly identified Fas-regulatory gene, TDAG51, was found to be dependent upon the activity of PKC. PKC activation only induced Fas expression in cells expressing wild-type TDAG51. Thus, Fas expression is likely mediated by PKC through TDAG51.
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
Determinants of specificity in TGF-beta signal transduction.
Signal transduction by the TGF-beta family involves sets of receptor serine/threonine kinases, Smad proteins that act as receptor substrates, and Smad-associated transcription factors that target specific genes. We have identified discrete structural elements that dictate the selective interactions between receptors and Smads and between Smads and transcription factors in the TGF-beta and BMP pathways. A cluster of four residues in the L45 loop of the type I receptor kinase domain, and a matching set of two residues in the L3 loop of the Smad carboxy-terminal domain establish the specificity of receptor-Smad interactions. A cluster of residues in the highly exposed alpha-helix 2 of the Smad carboxy-terminal domain specify the interaction with the DNA-binding factor Fast1 and, as a result, the gene responses mediated by the pathway. By establishing specific interactions, these determinants keep the TGF-beta and BMP pathways segregated from each other.
Activin Receptors, Type I↗
Association of p27Kip1 levels with recurrence and survival in patients with stage C prostate carcinoma.
BACKGROUND: There are few biologic determinants that are prognostic for patients with localized prostate cancer. We examined whether cellular levels of the cyclin-kinase inhibitor p27Kip1 (also known as p27) in prostate tumors could be used to predict progression of this disease. METHODS: Levels of p27 in tumor cell nuclei were assessed by immunohistochemical analysis of tissue sections from the primary tumors of 96 patients with stage C prostate carcinoma who had been treated by radical prostatectomy. Tumors were classified into one of the following three groups on the basis of the percentage of tumor cells showing nuclear p27 reactivity: low (0%-10%), moderate (11%-50%), and high (>50%). The Mantel-Haenszel test, Kaplan-Meier analysis, and the logrank test were used to calculate the probability that nuclear p27 levels were associated with tumor grade and substage, with a serum prostate-specific antigen (PSA) recurrence (defined as the finding of a detectable level [0.4 ng/mL or greater] of serum PSA following radical prostatectomy), with the recurrence of clinically evident disease, and with survival. All reported P values are two-sided. RESULTS: Luminal cells and basal cells of normal prostate glands showed high levels of nuclear p27 immunoreactivity in all tissue sections examined. Fifty-three tumors showed high p27 reactivity, 31 showed moderate reactivity, and 12 showed low or no detectable reactivity. Decreased levels of p27 were associated with tumor grade (P = .004). Tumor levels of p27 were not associated with preoperative prostate-specific antigen levels (P = .360) or with tumor substage (P = .320). However, decreased p27 reactivity was significantly associated with an increased probability of recurrence (P = .004) and decreased survival (P = .010). The median recurrence-free interval for patients with tumors showing high, moderate, or low p27 reactivity was 13.7 years, 8.4 years, and 4.7 years, respectively. Median survival times were more than 14 years, more than 13.5 years, and 8.1 years for patients in the high, moderate, and low p27 reactivity groups, respectively. CONCLUSION: Levels of nuclear p27 immunoreactivity in the primary tumor can be used to predict recurrence and survival among patients with localized prostate cancer.
Aged↗
The role of tumor necrosis factor alpha in modulating the quantity of peripheral blood-derived, cytokine-driven human dendritic cells and its role in enhancing the quality of dendritic cell function in presenting soluble antigens to CD4+ T cells in vitro.
Because dendritic cells (DC) are critically involved in both initiating primary and boosting secondary host immune responses, attention has focused on the use of DC in vaccine strategies to enhance reactivity to tumor-associated antigens. We have reported previously the induction of major histocompatibility complex class II-specific T-cell responses after stimulation with tumor antigen-pulsed DC in vitro. The identification of in vitro conditions that would generate large numbers of DC with more potent antigen-presenting cell (APC) capacity would be an important step in the further development of clinical cancer vaccine approaches in humans. We have focused attention on identifying certain exogenous cytokines added to DC cultures that would lead to augmented human DC number and function. DC progenitors from peripheral blood mononuclear cells (PBMC) were enriched by adherence to plastic, and the adherent cells were then cultured in serum-free XVIVO-15 medium (SFM) for 7 days with added granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). At day 7, cultures contained cells that displayed the typical phenotypic and morphologic characteristics of DC. Importantly, we have found that the further addition of tumor necrosis factor alpha (TNFalpha) at day 7 resulted in a twofold higher yield of DC compared with non-TNFalpha-containing DC cultures at day 14. Moreover, 14-day cultured DC generated in the presence of TNFalpha (when added at day 7) demonstrated marked enhancement in their capacity to stimulate a primary allogeneic mixed leukocyte reaction (8-fold increase in stimulation index [SI]) as well as to present soluble tetanus toxoid and candida albicans (10- to 100-fold increases in SI) to purified CD4+ T cells. These defined conditions allowed for significantly fewer DC and lower concentrations of soluble antigen to be used for the pulsing of DC to efficiently trigger specific T-cell proliferative responses in vitro. When compared with non-TNFalpha-supplemented cultures, these DC also displayed an increased surface expression of CD83 as well as the costimulatory molecules, CD80 and CD86. Removal of TNFalpha from the DC cultures after 2 or 4 days reduced its enhancing effect on DC yield, phenotype, and function. Thus, the continuous presence of TNFalpha over a 7-day period was necessary to achieve the maximum enhancing effect observed. Collectively, our findings point out the importance of exogenous TNFalpha added to cultures of cytokine-driven human DC under serum-free conditions, which resulted in an enhanced number and function of these APC. On the basis of these results, we plan to initiate clinical vaccine trials in patients that use tumor-pulsed DC generated under these defined conditions.
Antigen Presentation↗
Secondary structure of an antibacterial peptide Abp3 studied by two-dimensional proton-NMR.
An antibacterial peptide Abp3, an analogue of cecropin B, was investigated by two-dimensional proton-NMR at pH 5.0 in aqueous solution with 15% (v/v) hexafluoroisopropanol. The peptide, which consists of 35 amino acids, was synthesized chemically. Most resonances of the main-chain and side-chain protons were assigned. Several medium range NOE connectivities were observed, showing two separate alpha-helices with one amphiphilic in N-terminal domain (residues 5-21) and the other hydrophobic in C-terminal domain (residues 25-35) and a hinge region between them. The J coupling constants and the chemical shifts in these sections also supported the conclusion.
Amino Acid Sequence↗