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121.
The acid-induced unfolding of bovine liver glutamate dehydrogenase (GDH) was studied using various spectroscopic methods such as far- and near-UV circular dichroism (CD), intrinsic and 1-anilino naphthalene-8-sulphonate (ANS) extrinsic fluorescence spectroscopy, light scattering and fluorescence quenching in 20 mM mixed buffer at various pHs. CD spectra show that at pH 3.5, GDH retains its secondary structure substantially, whereas its tertiary structure content is reduced considerably. Intrinsic fluorescence of GDH and ANS binding suggest that, at pH 3.5, the hydrophobic surface of enzyme is more exposed in comparison to the native form. Acrylamide quenching indicates more exposure of tryptophan residues of enzyme at pH 3.5 in comparison to pH 7.5. Another partially unfolded intermediate was detected at pH 5.0, which with its ANS binding capacity lies between the pH 3.5 intermediate and the native form of the enzyme. Gel filtration results revealed that the enzyme at pH 3.5 is dissociated into trimeric species whereas it exists as hexamer at pH 7.5 and 5.0. All the data taken together suggest the existence of two partially unfolded states of GDH at moderate acidic pHs which may be considered as molten and pre-molten globule-like states. 相似文献
122.
M. Laura Ramos James J. Huntley Soheila J. Maleki Peggy Ozias-Akins 《Plant molecular biology》2009,69(3):325-335
Peanut (Arachis hypogaea L.), can elicit type I allergy becoming the most common cause of fatal food-induced anaphylactic reactions. Strict avoidance
is the only effective means of dealing with this allergy. Ara h 2, a peanut seed storage protein, has been identified as the
most potent peanut allergen and is recognized by approximately 90% of peanut hypersensitive individuals in the US. Because
peanut has limited genetic variation, wild relatives are a good source of genetic diversity. After screening 30 Arachis duranensis accessions by EcoTILLing, we characterized five different missense mutations in ara d 2.01. None of these polymorphisms induced major conformational modifications. Nevertheless, a polymorphism in the immunodominant
epitope #7 (S73T) showed a 56–99% reduction in IgE-binding activity and did not affect T cell epitopes, which must be retained
for effective immunotherapy. The identification of natural hypoallergenic isoforms positively contributes to future immunological
and therapeutic studies and peanut cultivar development.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
123.
Soheila Sarmadi Narges Izadi-Mood Kambiz Sotoudeh Seyed Mohammad Tavangar 《Diagnostic pathology》2009,4(1):1-6
Background
Primary non-Hodgkin lymphoma (NHL) of the breast represents 0.04–0.5% of malignant lesions of the breast and accounts for 1.7–2.2% of extra-nodal NHL. Most primary cases are of B-cell phenotype and only rare cases are of T-cell phenotype. Anaplastic large cell lymphoma (ALCL) is a rare T-cell lymphoma typically seen in children and young adults with the breast being one of the least common locations. There are a total of eleven cases of primary ALCL of the breast described in the literature. Eight of these cases occurred in proximity to breast implants, four in relation to silicone breast implant and three in relation to saline filled breast implant with three out of the eight implant related cases having previous history of breast cancer treated surgically. Adjuvant postoperative chemotherapy is given in only one case. Secondary hematological malignancies after breast cancer chemotherapy have been reported in literature. However in contrast to acute myeloid leukemia (AML), the association between lymphoma and administration of chemotherapy has never been clearly demonstrated.Case Presentation
In this report we present a case of primary ALCL of the breast arising in reconstruction mamoplasty capsule of saline filled breast implant after radical mastectomy for infiltrating ductal carcinoma followed by postoperative chemotherapy twelve years ago.Conclusion
Primary ALK negative ALCL arising at the site of saline filled breast implant is rare. It is still unclear whether chemotherapy and breast implantation increases risk of secondary hematological malignancies significantly. However, it is important to be aware of these complications and need for careful pathologic examination of tissue removed for implant related complications to make the correct diagnosis for further patient management and treatment. It is important to be aware of this entity at this site as it can be easily misdiagnosed on histologic grounds and to exclude sarcomatoid carcinoma, malignant melanoma and pleomorphic sarcoma by an appropriate panel of immunostains to arrive at the correct diagnosis of ALCL. 相似文献124.
Mohammad Hossein Karimi Padideh Ebadi Ali Akbar Pourfathollah Zahra Soheila Soheili Seyed Mohammad Moazzeni 《Cytotechnology》2010,62(3):195-199
CD40-CD154 interaction is an important process for cellular and humoral immunity regulation and can be effective in the body’s
defense against tumors. In the present study, we evaluated the expression of CD40 in Wehi-164 cell line. CD40 expressions
on the cell surface and in the cytoplasm were assessed by flow cytometry and intracellular staining assay, respectively. Also,
the mRNA expression was identified by real time-PCR. The obtained results showed the high mRNA and cytoplasmic protein expression
of CD40 but no surface expression. These results suggest that the Wehi-164 cell line down regulates expression of CD40 on
the surface for evasion of immune system. 相似文献
125.
The objectives of this study were to characterize the effects of a chronic lithium (Li+) treatment on serotonin (5-HT) uptake sites and on 5-HT1A receptors, and to determine the eventual reversibility of the treatment. The experiments were carried out with membranes from rat cerebral cortex using 8-hydroxy-2-(propylamino)tetralin, or [3H]8-OH-DPAT, and [3H]citalopram to label 5-HT1A receptors and 5-HT uptake sites, respectively. Endogenous levels of 5-HT and 5-hydroxyindole-3-acetic acid (5-HIAA) were measured by high-performance liquid chromatography in the cingulate cortex. The saturation curves with [3H]8-OH-DPAT were always best fitted a two-site model. After a treatment with Li+ for 28 days, no alterations in the binding parameters of [3H]8-OH-DPAT to the high- and low-affinity binding sites could be documented. However, competition curves with 5-HT to inhibit [3H]8-OH-DPAT binding revealed a decreased proportion of sites with high affinity for the agonist, together with an increased density of sites with low affinity for 5-HT, suggesting an alteration in the coupling efficacy between 5-HT1A receptors and their transduction systems. Saturation studies with [3H]citalopram showed an increase (>40%) in the density of 5-HT uptake sites after chronic Li+, suggesting a more efficient 5-HT uptake process for the treated animals, in accord with clinical observations. Although 5-HT contents in cingulate cortex remained unchanged after the treatment, 5-HIAA levels decreased (>30%), leading to a diminished (almost 50%) 5-HT turnover; and also reflecting a more efficient uptake in the treated rats, so that less 5-HT could be degraded by extracellular monoamine oxidase. All the effects revealed by [3H]8-OH-DPAT and [3H]citalopram were reversed following a recovery period of two days without Li+. Since symptoms of bipolar affective disorders may reappear if the chronic Li+ treatment is interrupted, the reversibility of the observed effects further supports the importance of central 5-HT synaptic transmission in the pathophysiology and treatment of human affective disorders. 相似文献
126.
† Kim S. Sugamori † Soheila A. Hamadanizadeh ‡Mark A. Scheideler ‡Rolf Hohlweg §Philippe Vernier † Hyman B. Niznik 《Journal of neurochemistry》1998,71(4):1685-1693
Abstract: Although members of the multiple vertebrate/mammalian dopamine D1 receptor gene family can be selectively classified on the basis of their molecular/phylogenetic, structural, and tissue distribution profiles, no subtype-specific discriminating agents have yet been identified that can functionally differentiate these receptors. To define distinct pharmacological/functional attributes of multiple D1-like receptors, we analyzed the ligand binding profiles, affinity, and functional activity of 12 novel NNC compounds at mammalian/vertebrate D1/D1A and D5/D1B, as well as vertebrate D1C/D1D, dopamine receptors transiently expressed in COS-7 cells. Of all the compounds tested, only NNC 01-0012 displayed preferential selectivity for vertebrate D1C receptors, inhibiting [3 H]SCH-23390 binding with an estimated affinity (∼0.6 n M ) 20-fold higher than either mammalian/vertebrate D1/D1A or D5/D1B receptors or the D1D receptor. Functionally, NNC 01-0012 is a potent antagonist at D1C receptors, inhibiting to basal levels dopamine (10 µ M )-stimulated adenylyl cyclase activity. In contrast, NNC 01-0012 (10 µ M ) exhibits weak antagonist activity at D1A receptors, inhibiting only 60% of maximal cyclic AMP production by dopamine, while acting as a partial agonist at vertebrate D1B and D1D receptors, stimulating adenylyl cyclase activity by ∼33% relative to the full agonist dopamine (10 µ M ), an effect that was blocked by the selective D1 receptor antagonist NNC 22-0010. These data clearly suggest that the benzazepine NNC 01-0012, despite lacking the N -methyl residue in the R3 position, is a selective and potent D1C receptor antagonist. Moreover, the differential signal transduction properties exhibited by NNC 01-0012 at these receptor subtypes provide further evidence, at least in vertebrates, for the classification of the D1C receptor as a distinct D1 receptor subtype. 相似文献
127.
Nader Riyahi-Alam Zhaleh Behrouzkia Alexander Seifalian Soheila Haghgoo Jahromi 《Biological trace element research》2010,137(3):324-334
Nanosized materials of gadolinium oxide can provide high-contrast enhancement in magnetic resonance imaging (MRI). The aim
of this research was to characterize a novel emulsion composed of a silicon-based nanocomposite polymer (NCP) and gadolinium
(III) oxide (Gd2O3) nanoparticles. The size and morphological structure of this nanoparticle are determined by particle size analysis device
(zeta sizer) and transmission electronic microscope. We determined composition of Gd2O3 nanoparticles with energy dispersive X-ray analysis (EDXA) and magnetic resonance signal by T
1-weighted MRI. Cytotoxicity of Gd2O3 nanoparticles in SK-MEL-3 cancer cells was evaluated. Zeta sizer showed Gd2O3 nanoparticles to be 75 nm in size. EDXA indicated the two main chemical components of gadolinium-nanocomposite polymer emulsion:
gadolinium and silicon and MRI also showed a significantly higher incremental relaxivity for Gd2O3 nanoparticles compared to Magnevist (conventional contrast agent). In such concentrations, the slope of R1 relaxivity (1/T
1) vs. concentration curve of Magnevist and Gd2O3 were 4.33, 7.98 s−1 mM−1. The slope of R2 relaxivity (1/T
2) vs. concentration curve of Magnevist and Gd2O3 were 5.06, 13.75 s−1 mM−1. No appreciable toxicity was observed with Gd2O3 nanoparticles. Gadolinium-nanocomposite polymer emulsion is well characterized and has potential as a useful contrast agent
for magnetic resonance molecular imaging. 相似文献
128.
The interaction of native calf thymus DNA with Diazinon, an organophophorus insecticide, in HEPES buffer at neutral pH, was monitored by UV absorption spectrophotometry, circular dichroism (CD), electrochemical technique, and fluorescence spectroscopy. UV spectra showed hyperchromicity and blue shift with the increase of Diazinon concentration. Fluorescence spectroscopy results indicated that the probable quenching mechanism of DNA-ethidium bromide (EB) fluorescence by Diazinon is a dynamic quenching procedure, because the Stern-Volmer quenching constant (K(SV)) increased with the temperature rising. Unchanging of the CD signal around 280 nm with increasing ratio of Diazinon to DNA is an important evidence for non-intercalative-binding mode of Diazinon with DNA. Stoichiometry measurement of the DNA-nDiazinon indicated that a stable 1:2 complex of DNA-Diazinon was formed under the selected conditions. The electrochemical study of the Diazinon-DNA interaction was carried out by incubation of DNA with Diazinon in the presence of varying amounts of selenium (Se). This technique revealed that Se is able to diminish the DNA damage effect of Diazinon. 相似文献
129.
A novel one-pot three-component condensation reaction of an aldehyde, β-ketoester and 2-aminobenzimidazole or 2-aminobenzothiazole in 1,1,3,3-N,N,N′,N′-tetramethylguanidinium trifluoroacetate as an ionic liquid is described. During the course of this reaction 4H-pyrimido[2,1-b]benzimidazoles or 4H-pyrimido[2,1-b]benzothiazoles are formed in high yields at 100 °C. The ionic liquid can be recovered conveniently and reused efficiently. 相似文献
130.
The control of virulence gene expression in the human pathogen Staphylococcus aureus is under the partial control of the two-component quorum-sensing system encoded by genes of the agr locus. The product of the agrA gene has been shown by amino acid sequence similarity to be the putative response regulator; however, binding of AgrA to promoters under its control has not yet been demonstrated. In this study, we isolated and purified soluble AgrA by expression under osmotic shock conditions and ion-exchange chromatography. Purified AgrA showed high-affinity binding to the RNAIII-agr intergenic region by electrophoretic mobility shift assays. Binding was localized by DNase I protection assays to a pair of direct repeats in the P2 and P3 promoter regions of the agr locus. We found that this binding was enhanced by the addition of the small phosphoryl donor, acetyl phosphate. The difference in binding affinity between these two promoters was found to result from a 2-bp difference between the downstream direct repeats of the P2 and P3 sites. Mutation of these base pairs in the P3 site to match those found in the P2 site increased the affinity of AgrA for the P3 site relative to that for the P2 site. These results are consistent with the function of AgrA as a response regulator with recognition sites in the promoter regions of RNAIII and the agr locus. 相似文献