Predicted c(2 x 2) buckling reconstruction of monolayer Mn on Fe(001) and its importance to the interfacial magnetic ordering.
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Journal Article↗
Biomedical subjects
R Wu
Publications and source records attributed to R Wu.
Structure and bonding at metal-ceramic interfaces: Ag/CdO(001).
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Journal Article↗
Metal-ceramic interfaces: Overlayer-induced reconstruction and magnetism of 4d transition-metal monolayers.
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Journal Article↗
Two nuclear proteins in tracheal epithelial cells are recognized by antibodies specific to a squamous differentiation marker, sprI.
In cell-free translations of RNA from primary cultures of pig trachea surface epithelial cells we observed that a mRNA encoding a 20 kDa proline-rich protein (sPRP) was dramatically induced during culturing (Tesfaigzi et al., 1990, Biochem. Biophys. Res. Commun., 172:M1304-1309). This mRNA was not detected in tracheal tissue or in epithelial cells prior to culturing. Antisera were raised to synthetic peptide sequences corresponding to 23 amino acids on the C-terminus (C23-antiserum) and 29 amino acids on the N-terminus (N29 antiserum) of sPRP. On Western blot analysis, C23 antiserum reacted with a 20 kDa protein in cytosolic extracts from pig tracheal cells maintained in culture for 4 days. The reaction with the 20 kDa protein was inhibited by adding C23 peptide. Two nuclear proteins (66 and 70 kDa) obtained by micrococcal nuclease treatment of tracheal cell nuclei were detected on Western blots with C23 antiserum. These proteins were present in cells both before and after culturing. Sucrose gradient fractionation indicated that these nuclear proteins are associated with chromatin. Small amounts of the 66 and 70 kDa proteins were obtained from nuclear matrix fractions. These nuclear proteins also reacted with N29 antiserum. Since these proteins share similar epitopes with the N- and C-termini of sPRP, it is likely that the 20 kDa protein (sPRP) is part of these proteins. However, purification of the nuclear proteins followed by an amino acid sequence analysis is necessary to clarify whether sPRP is part of these proteins.
Amino Acid Sequence↗
Expression of the rice Osgrp1 promoter-Gus reporter gene is specifically associated with cell elongation/expansion and differentiation.
To study the expression and regulation of a rice glycine-rich cell wall protein gene, Osgrp1, transgenic rice plants were regenerated that contain the Osgrp1 promoter or its 5' deletions fused with the bacterial beta-glucuronidase (GUS) reporter gene. We report here a detailed histochemical analysis of the Osgrp1-Gus expression patterns in transgenic rice plants. In roots of transgenic rice plants, GUS expression was specifically located in cell elongation and differentiation regions, and no GUS expression was detectable in the apical meristem and the mature region. In shoots, GUS activity was expressed only in young leaves or in the growing basal parts of developing leaves, and little GUS activity was expressed in mature leaves or mature parts of developing leaves. In shoot apices, GUS activity was detected only in those leaf cells which were starting to expand and differentiate, and GUS expression was not detected in the apical meristem and the young meristematic leaf primordia. GUS activity was highly expressed in the young stem tissue, particularly in the developing vascular bundles and epidermis. Thus, the expression of the Osgrp1 gene is closely associated with cell elongation/expansion during the post-mitotic cell differentiation process. The Osgrp1-Gus gene was also expressed in response to wounding and down-regulated by water-stress conditions in the elongation region of roots. Promoter deletion analysis indicates that both positive and negative mechanisms are involved in regulating the specific expression patterns. We propose a simple model for the developmental regulation of the Osgrp1 gene expression.
Base Sequence↗
A gibberellin-stimulated ubiquitin-conjugating enzyme gene is involved in alpha-amylase gene expression in rice aleurone.
A ubiquitin-conjugating enzyme (UBC) gene, induced by gibberellin (GA) within an hour, was identified in rice (Oryza sativa) seeds by the mRNA differential display technique. GA inducibility was confirmed by RNA hybridization. A full-length UBC cDNA clone and a genomic clone have been isolated and sequenced. The deduced amino acid sequence shares a significant identity with several known UBC sequences, which are probably involved in the pathway responsible for degrading short-lived regulatory proteins. In vivo transient assays using the UBC gene promoter, joined to the luciferase cDNA as the reporter gene, showed that the sequence located between positions 231 and 159 upstream of the transcription start site of this promoter is crucial for GA-dependent activation of the luciferase cDNA. Finally, trans-activation experiments indicated that this UBC gene is involved in gibberellin-stimulated alpha-amylase gene expression.
Amino Acid Sequence↗
Growth and biochemical effects of unsymmetrically substituted polyamine analogues in human lung tumor cells 1.
Three unsymmetrically substituted polyamine analogues demonstrate significant and selective antitumor effects. Each of the analogues N1-ethyl-N11-propargyl-4,8-diazaundecane (PENSpm), N1-ethyl-N11-(cyclobutyl)methyl-4,8-diazaundecane (CBENSpm), and N1-ethyl-N11-(cyclopropyl)methyl-4,8-diazaundecane (CPENSpm) is cytotoxic to a representative non-small-cell lung carcinoma line, NCI H157, while being only growth-inhibitory to a representative small-cell-lung carcinoma line, NCI H82. Cytotoxicity is accompanied by a significant increase in expression of the polyamine catabolic enzyme spermidine/spermine N1-acetyltransferase (SSAT) at the levels of activity and steady-state mRNA. These new analogues are significant both for their cell-type-specific activity and as synthetic prototypes for the addition of SSAT-activated functional groups.
Acetyltransferases↗
Structure-function studies of mEGF: probing the type I beta-turn between residues 25 and 26.
The interaction between epidermal growth factor (EGF) and its receptor molecule is not completely understood and has received much attention recently. Studies combining site-directed mutagenesis and NMR spectroscopy have identified a number of EGF residues that are required for activity and are believed to interact directly with the receptor. Instead of focusing on these residues, this study combines site-directed mutagenesis and NMR spectroscopy to probe the role of the type I beta-bend located between residues 25 and 26 of the N-terminal subdomain of the protein. Ser25 of murine EGF is replaced by Pro in an attempt to stabilize this turn conformation to produce a variant of mEGF with increased activity relative to that for the native protein. Ser25 is also replaced by Ala, which is found at position 25 in human EGF (hEGF), as a more conservative replacement. Receptor binding studies demonstrate that both mutations produce about a 30% reduction in binding affinity, which is shown to result from local changes within the loop or minor perturbations of residues neighboring the loop rather than from long-range perturbations of the beta-sheet of the N-terminal subdomain. The type I beta-turn appears to remain intact in both mutants; however, replacement with Pro seems to introduce more flexibility into this region of the protein. These results demonstrate that perturbation of this beta-turn has little effect on EGF-receptor interactions.
Animals↗
Thermostabilization of live virus vaccines by heavy water (D2O).
Eradication of poliomyelitis is based on the mass administration of oral poliovirus vaccine (OPV). Delivery of effective vaccines in the developing world, especially in tropical areas, is compromised when refrigeration cannot be assured. The OPV, prepared with three live attenuated polioviruses (Sabin strains, serotypes 1, 2 and 3), is considered to be the most thermolabile of vaccines in the World Health Organization's Expanded programme on Immunization. To be effective, the initial concentration (potency of each of the three component serotypes, measured in tissue culture infective doses, should not decrease by more than 0.5 log10 before vaccine delivery. High concentration (1 M) of MgCl2 is currently used as stabilizer for OPV. The stabilizing effect of D2O was tested here on OPV strains. By diluting the viral suspension with D2O-based salt and buffer solutions, in a manner similar to that involved in OPV production an 87% concentration of D2O in the final viral preparation was achieved. In severe conditions of testing (incubation for 3 days at 45 degrees C), the Sabin 3 virus lost an average of 2.7 log10 potency in the presence of 87% D2 as compared to 3.0 log10 in H2O-based 1 M MgCl2, and to 5.7 log10 in the H2O-based control solutions. When tested in a combined 87% D2O and 1 M MgCl2 treatment, the Sabin 3 virus lost only 1.3 log10 potency after 3 days at 45 degrees C. Similar thermostabilizing effects were obtained for Sabin 1 and Sabin 2 strains, but the level of stabilization was slightly lower. Tested in standard conditions at 37 degrees C for 7 days, the infectivity of the three D2O MgCl2-treated OPV strains remained in the limit of requirements ( < or = 0.5 log10). The stabilizing effect of D2O was also demonstrated on yellow fever 17D vaccine virus strain.
Cell Line↗
A rice membrane calcium-dependent protein kinase is induced by gibberellin.
A rice (Oryza sativa) seed plasma-membrane calcium-dependent serine/threonine protein kinase (CDPK) has been partially purified. Comparing results in seeds that were treated with and without the plant hormone gibberellin (GA) for 10 min showed that rice CDPK was highly induced by GA. After separating solubilized membrane proteins by sodium dodecyl sulfate-gel electrophoresis, followed by renaturation, a radiolabeled phosphoprotein band of approximately 58 kD was detected, and it was apparently produced by autophosphorylation. There are five aspects of the rice CDPK that show similarity to mammalian protein kinase C (PKC) and to other plant CDPKs: (a) Histone IIIS and PKC peptide-ser25 (19-31) are phosphorylated by rice CDPK. (b) The phosphorylation reaction is strictly dependent on calcium. (c) The activity of the rice CDPK is inhibited by either staurosporine or the PKC inhibitory peptide (19-36). (d) Addition of calmodulin has no effect on the activity of the enzyme; however, the CDPK is inhibited by the calmodulin antagonists trifluoperazine and W-7. (e) The rice CDPK reacts with a mammalian anti-PKC antibody in immunoblotting analysis. However, there is one major difference between the rice CDPK and other CDPKs: the rice CDPK is induced by GA, whereas no mammalian PKC or other plant CDPKs are known to be induced by any hormone.
Animals↗
Autoantibodies against oxidized low density lipoproteins (oxLDL): characterization of antibody isotype, subclass, affinity and effect on the macrophage uptake of oxLDL.
Circulating antibodies against oxLDL are present in several inflammatory and autoimmune conditions. Such antibodies are also present in patients with atherosclerosis, although the pathogenic significance of the antibodies is still not known. We have characterized the antibodies with regard to isotype, subclass, affinity and effect on macrophage uptake of oxLDL. Antibodies of IgG and IgM isotype were most common and found both in patients with atherosclerosis and in normal individuals. The subclass of IgG antibodies was mainly IgG2 and IgG3. Scatchard analyses of IgG and IgM antibodies showed that IgG antibodies were heterogeneous with regard to affinity, whereas only one population of high-affinity antibodies was found in the IgM antibody population. The high-affinity populations had an average equilibrium constant (K0) of 8.84 x 10(9) M-1 for IgG antibodies and of 1.65 x 10(9) M-1 for IgM antibodies. Incubation of 125I-oxLDL with purified IgG and IgM from sera with high amounts of antibodies enhanced the uptake of 125I-oxLDL in the monocyte-like U937 cell line. Antibody preparations from sera containing no anti-oxLDL antibodies and from sera with antibodies against LDL had less effect on this uptake. The increased uptake was competitively decreased by adding unlabelled oxLDL. This study shows that antibodies against oxLDL are mainly IgG2, IgG3 and IgM. Both IgG and IgM antibodies have a high affinity for the antigen and increase the uptake of oxLDL in a monocyte-like cell line.
Antibody Affinity↗
Encephalocraniocutaneous lipomatosis with a mutation in the NF1 gene.
Encephalocraniocutaneous lipomatosis (ECCL) is a congenital hamartomatous disorder characterised by unilateral skin lesions, lipomas, and ipsilateral ophthamological and cerebral malformations. The disorder is thought to represent a localised form of Proteus syndrome. In this report, a child is described with ECCL and a de novo nonsense mutation in exon 29 (S1745X) of the neurofibromatosis type 1 (NF1) gene. Although it is possible that both ECCL and NF1 occur coincidentally in this patient, we favour the hypothesis that in exceptional cases a mutation in the NF1 gene might give rise to severe congenital malformations such as ECCL. Possible pathogenetic mechanisms for these malformations are discussed.
Base Sequence↗
BamHI and HindIII repetitive DNA families in the rice genome.
In this paper we describe a novel method of cloning representative members of different repetitive DNA families based on the screening of a rice (Oryza sativa) genomic library using DNA from different C0t fractions as probes. Two genomic clones, which represent two different repetitive DNA families in rice, were isolated by this method and have been characterized. Their nucleotide sequences, copy numbers, distributions in major rice genome types, methylation patterns, and chromosomal localizations were determined.
Base Sequence↗
Glutathione S-transferases in tracheobronchial epithelium.
The purpose of this study is to characterize glutathione S-transferase (GST) gene expression in airway epithelium both in vivo and in vitro. Immunohistochemical staining of nonhuman primate lungs of well-controlled healthy animals reveals the presence of alpha- and pi-class GST isoenzymes in ciliated bronchial epithelium. The stain of mu-GST antibody is either very low or absent in some of these monkey lungs. We observed that primary tracheobronchial epithelial (TBE) cells isolated from human and monkey pulmonary tissues maintain a relatively high level of GST enzymatic activity in culture, compared with various immortalized human TBE cell lines and other nonpulmonary cell lines. Northern blot analysis demonstrated the presence of mu-, pi-, and microsomal-GST messages but not the alpha-class message in cultures of primary TBE cells as well as in various human TBE cell lines. The expression of mu- and pi-class GST genes can be further regulated in culture by various environmental factors; however, most of these regulating factors are associated with TBE cell differentiation in culture. For instance, vitamin A treatment, which was shown to enhance mucous cell differentiation in vitro, stimulated the message levels of mu- and pi-class GST. Furthermore, plating cells on collagen gel substrata, which also enhanced mucous cell differentiation in culture, instead of plastic culture surface, enhanced total GST enzymatic activity by eightfold, and this enhancement is related to an increase in the expression of the pi-class GST gene. These results demonstrated that GST genes are differentially expressed and regulated by various environmental factors in primary TBE cells and various cell lines, and the regulation is correlated to the mucous cell differentiation in culture.
Animals↗
Patients with early-onset peripheral vascular disease have increased levels of autoantibodies against oxidized LDL.
Oxidative modification of LDL has been proposed as an early and crucial step in the development of atherosclerosis, and antibodies against such modified LDL are found in both healthy individuals and patients with atherosclerosis. In this study, 62 patients who were surgically treated for peripheral arterial occlusive disease below the age of 50 were investigated and compared with age- and sex-matched healthy individuals in a case-control study. Autoantibodies against oxidized LDL were measured with an enzyme-linked immunosorbent assay method. Risk factors such as smoking, hypertension, family history of premature cardiovascular events, and lipoprotein levels were also determined. The patients had significantly higher levels of autoantibodies against oxidized LDL; significantly higher levels of total cholesterol, LDL cholesterol, triglycerides, and apo A-I; and significantly lower levels of HDL cholesterol than did control subjects. In multivariate analyses autoantibodies against oxidized LDL discriminated better between patients and control subjects than did any of the different lipoprotein analyses. Among patients, the presence of hypertension and a family history of cardiovascular events were the only factors significantly associated with increased levels of autoantibodies against oxidized LDL.
Adult↗
Changes in pulmonary function test results after 1 year of therapy as predictors of survival in patients with idiopathic pulmonary fibrosis.
The study group consisted of 58 patients with idiopathic pulmonary fibrosis (IPF) recognized between 1970 and 1991 who were treated for their pulmonary disease, survived for at least 1 year from the time of initiation of treatment, and had forced vital capacity (FVC) measurements at the time of diagnosis and 9 to 15 months later. Forty-four of the patients also had a single-breath diffusing capacity (Dsb) measured initially and after 9 to 15 months of treatment and 33 patients had an arterial blood gas, breathing room air at the time of diagnosis and 9 to 15 months into therapy. Patients' conditions were classified as improved, unchanged, or worse after the year of treatment based on each of the three pulmonary function tests. A > or = 10% increase in FVC, > or = 20% increase in Dsb, and > or = 5 mm Hg decrease in alveolar-arterial difference in oxygen partial pressure [P(A-a)O2] defined improved function. A > or = 10% decrease in FVC, > or = 20% decrease in Dsb, and > or = 5 mm Hg increase in P(A-a)O2 defined worse function. Patients with < 10% change in FVC, < 20% change in Dsb, and < 5 mm Hg change in P(A-a)O2 were regarded as having unchanged conditions. Kaplan-Meier survival plots and the Cox proportional hazard regression model were used to analyze survival time in relation to change in pulmonary function after 1 year of therapy. Patients with an improved or unchanged FVC at 1 year had no difference in survival (p = 0.75), but both showed enhanced survival compared with patients with a > or = 10% reduction in FVC with 1 year of treatment (p < 0.001). Patients with an improved or unchanged Dsb at 1 year also had no difference in survival (p = 0.21) but again, both showed enhanced survival compared with patients with > or = 20% decrease in Dsb with 1 year of treatment (p < 0.001). Changes in gas exchange after 1 year of treatment did not correlate with survival in the three groups. There was a trend for longer survival in improved patients compared with those with worsening gas exchange, but the p value was not significant at 0.17. We conclude that changes in the FVC and Dsb after 1 year of treatment are strongly predictive of duration of survival in patients with IPF.
Adult↗
[Relation between selenium and cancer of uterine cervix].
Selenium (Se) concentration in serum, hair, normal cervix tissue or tissue of cervix cancer of 20 cases with cancer of uterine cervix (survey group), 21 with myoma of the uterus and 1 with cervical polys (control group), but also in rice, water and soil in the high and low incidence areas of cervical cancer was determined. The results showed that Se concentration in serum and cancer tissue of uterine cervix in patients with cancer of uterine cervix was significantly lower than that in the control group (P < 0.05), but no significant difference of Se concentration in hair was observed (P > 0.05), However Se concentration in rice, water and soil in the high incidence areas of cervical cancer was significantly lower than that in the low incidence areas (P < 0.05). Se deficiency may play a role in the carcinogenesis of uterine cervix.
Adenocarcinoma↗
[Morphometric studies of effects of clomiphene citrate on histological characteristics of proliferative endometrium].
OBJECTIVES: To analyse quantitatively the effects of clomiphene citrate (CC) on histological characteristics of proliferative endometrium. METHODS: Endometrium biopsies were performed on day 12th of both natural and CC cycles in 14 infertile patients. Nuclear size, shapes and DNA contents of epithelial and glandular epithelial cells, stromal cells were measured or calculated after HE and Feulgeu staining by computerized image analysis technique. Results were compared before and after CC treatment. RESULTS: The average area, girth and maximal diameter of the nucler of glandular and epithelial cells in CC cycles were significantly smaller than those of natural cycles (P < 0.05), while the shape factor of stromal nuclea in CC cycles was larger than the natural ones (P < 0.05). DNA contents of glandular, epithelial and stromal nuclea in CC cycles were also smaller than those of natural cycles (P < 0.02). The difference of nuclear DNA content between the 2 cycles was positively correlated with the difference of nuclear area of glandular and epithelial cells (P < 0.01). CONCLUSIONS: CC treatment inhibited the endometrial mitosis and proliferation. This effects may begin at the stage of DNA synthesis, therfore DNA contents of endometrial glandular and stromal nuclea also decreased. The action of CC may be related to estrogen receptor synthesis.
Adult↗