julilili42/papers huggingface dataset:
AML1/MTG8 oncogene suppression by small interfering RNAs supports myeloid differentiation of t(8;21)-positive leukemic cells
2003-04-02

Abstract The translocation t(8;21) yields the leukemic fusion gene AML1/MTG8 and is associated with 10%-15% of all de novo cases of acute myeloid leukemia. We demonstrate the efficient and specific suppression of AML1/MTG8 by small interfering RNAs (siRNAs) in the human leukemic cell lines Kasumi-1 and SKNO-1. siRNAs targeted against the fusion site of the AML1/MTG8 mRNA reduce the levels of AML1/MTG8 without affecting the amount of wild-type AML1. These data argue against a transitive RNA interference mechanism potentially induced by siRNAs in such leukemic cells. Depletion of AML1/MTG8 correlates with an increased susceptibility of both Kasumi-1 and SKNO-1 cells to tumor growth factor β1 (TGFβ1)/vitamin D3–induced differentiation, leading to increased expression of CD11b, macrophage colony-stimulating factor (M-CSF) receptor, and C/EBPα (CAAT/enhancer binding protein). Moreover, siRNA-mediated AML1/MTG8 suppression results in changes in cell shape and, in combination with TGFβ1/vitamin D3, severely reduces clonogenicity of Kasumi-1 cells. These results suggest an important role for AML1/MTG8 in preventing differentiation, thereby propagating leukemic blast cells. Therefore, siRNAs are promising tools for a functional analysis of AML1/MTG8 and may be used in a molecularly defined therapeutic approach for t(8;21)-positive leukemia.
Continental European Eemian and early Würmian climate evolution: comparing signals using different quantitative reconstruction approaches based on pollen
2003-04-04

Analyses of Eemian climate dynamics based on different reconstruction methods were conducted for several pollen sequences in the northern alpine foreland. The modern analogue and mutual climate sphere techniques used, which are briefly presented, complement one another with respect to comparable results. The reconstructions reveal the occurrence of at least two similar thermal periods, representing temperate oceanic conditions warmer and with a higher humidity than today. Intense changes of climate processes become obvious with a shift of winter temperatures of about 15 °C from the late Rissian to the first thermal optimum of the Eemian. The transition shows a pattern of summer temperatures and precipitation increasing more rapidly than winter temperatures. With the first optimum during the Pinus–Quercetum mixtum–Corylus phase (PQC) at an early stage of the Eemian and a second optimum period at a later stage, which is characterised by widespread Carpinus, climate gradients across the study area were less intense than today. Average winter temperatures vary between −1.9 and 0.4 °C (present-day −3.6 to 1.4 °C), summer temperatures between 17.8 and 19.6 °C (present-day 14 to 18.9 °C). The timberline expanded about 350 m when compared to the present-day limit represented by Pinus mugo. Whereas the maximum of temperature parameters is related to the first optimum, precipitation above 1100 mm is higher during the second warm period concomitant to somewhat reduced temperatures. Intermediate, smaller climate oscillations and a cooling becomes obvious, which admittedly represent moderate deterioration but not extreme chills. During the boreal semicontinental Eemian Pinus–Picea–Abies phase, another less distinct fluctuation occurs, initiating the oscillating shift from temperate to cold conditions.
Human malignant glioma cells express semaphorins and their receptors, neuropilins and plexins
2003-04-07

Abstract Semaphorins comprise a family of molecules implicated in the guiding of growing axons and neuronal progenitor cells. Further, semaphorins have been suggested to play a role in cancer metastasis. Neuropilins 1 and 2 are cell surface receptors for soluble class 3 semaphorins. Plexins are direct receptors for membrane‐bound semaphorins and, by binding to neuropilins, coreceptors necessary for class 3 semaphorin signaling. We here report that human malignant glioma cell lines express neuropilins 1 and 2 mRNA and protein, as well as either plexin A1, A2, or B1. Further, all glioma cell lines express SEMA3A and SEMA3C and exhibit SEMA3A binding sites. Exogenous SEMA3A expressed in 293 or U87MG cells has no collapsing or chemorepulsive activities on glioma cells as determined by F‐actin staining and collagen coculture assays. In summary, human glioma cells express class 3 semaphorins and receptors for soluble and membrane‐bound semaphorins, suggesting a possible role of the semaphorin/neuropilin system in the interactions of human malignant glioma with the host's central nervous and immune systems. GLIA 42:379–389, 2003. © 2003 Wiley‐Liss, Inc.
Rearing in different photic and spectral environments changes the optomotor response to chromatic stimuli in the cichlid fish Aequidens pulcher
2003-04-07

SUMMARY Developmental plasticity of spectral processing in vertebrates was investigated in fish by using an innate behavior, the optomotor response. Rearing blue acara (Aequidens pulcher; Cichlidae) under white lights of different intensities as well as deprivation of long wavelengths induced significant changes in the animals' responses to chromatic stimuli. Deprivation of short wavelengths had no effect. With this and previous studies on animals reared under similar conditions, we have demonstrated that developmental plasticity in spectral processing is present at a wide range of neural levels, spanning from photoreceptors to behavior. We hypothesize that earlier studies did not reveal such effects because of the rearing and testing conditions used.
Effect of endothelin‐1 on astrocytic protein content
2003-04-07

Abstract The astrocytic endothelin (ET) receptors, ET A and ET B , modulate calcium signaling and the astrocytic gap junctional network. The nonselective ET receptor ligand ET‐1 inhibits gap junction permeability, an effect that can be blocked by tolbutamide. This mechanism may play a role in pathophysiological conditions such as ischemic stroke, characterized by elevated tissue ET‐1 levels and hypertrophic‐appearing reactive astrocytes. Therefore, the effect of ET‐1 on cellular protein content was investigated in confluent once‐passaged rat astrocyte cultures under serum‐free conditions, by the Lowry method. Gap junction permeability was determined by the dye transfer technique. ET‐1 prevented the decrease in astrocytic protein content observed in controls. The effect of ET‐1 on cellular protein content was most pronounced in cultures seeded at high density, but it was attenuated in ET B ‐deficient (sl/sl) astrocytes. This effect could be blocked by the nonselective ET antagonist LU 302872 (10 μM), as well as by the protein synthesis inhibitor cycloheximide (10 μM). This increase in astrocytic protein content was inhibited by the ATP‐sensitive K + channel blocker tolbutamide, which also antagonized the ET‐1‐induced reduction of gap junction permeability and reversed the morphological changes observed in astrocytes upon ET‐1 treatment. Cytosine arabinoside (10 μM), a DNA synthesis blocker, inhibited the ET‐1‐induced BrdU uptake without affecting the ET‐1‐induced increase in astrocytic protein content. To conclude, ET‐1 induces an increase in astrocytic protein content as well as changes in astrocyte morphology in vitro. This hypertrophic response involves uncoupling of the astrocytic gap junctional network and is not dependent on DNA synthesis. GLIA 42:390–397, 2003. © 2003 Wiley‐Liss, Inc.
Characterization of the Aspergillus nidulans transporters for the siderophores enterobactin and triacetylfusarinine C
2003-04-09

The filamentous ascomyceteAspergillus nidulans produces three major siderophores: fusigen, triacetylfusarinine C, and ferricrocin. Biosynthesis and uptake of iron from these siderophores, as well as from various heterologous siderophores, is repressed by iron and this regulation is mediated in part by the transcriptional repressor SREA. Recently we have characterized a putative siderophore-transporter-encoding gene (mirA). Here we present the characterization of two further SREA- and iron-regulated paralogues (mirB and mirC), including the chromosomal localization and the complete exon/intron structure. Expression of mirA and mirB in a Saccharomyces cerevisiae strain, which lacks high affinity iron transport systems, showed that MIRA transports specifically the heterologous siderophore enterobactin and that MIRB transports exclusively the native siderophore triacetylfusarinine C. Construction and analysis of an A. nidulans mirA deletion mutant confirmed the substrate specificity of MIRA. Phylogenetic analysis of the available sequences suggests that the split of the species A. nidulans and S. cerevisiae predates the divergence of the paralogous Aspergillus siderophore transporters.
Tetramethylphosphonium Fluoride:  “Naked” Fluoride and Phosphorane
2003-04-09

Me(4)PF was investigated in the solid state, in the gas phase, and in solutions. Vibrational spectra of the solid and a single-crystal structure show an ionic tetramethylphosphonium fluoride. The compound crystallizes in the space group Pbca with a = 1016.0(1), b = 1018.0(1), c = 1205.8(4) pm, and Z = 8. The fluoride ion is nearly trigonal planar surrounded by three Me(4)P+ cations forming six H...F contacts between 218 and 240 pm. The compound is stable below 120 degrees C and sublimes in a vacuum. It possesses a phosphorane structure in the gas phase that was studied by electron diffraction and vibrational spectra, and additionally by theoretical calculations. The Me(4)PF molecule has a trigonal bipyramidal structure with one methyl group and the fluorine atom in axial positions and bond lengths of d(PC(eq)) = 182.6(4) pm, d(PC(ax)) = 188.4(8) pm, and d(PF) = 175.3(6) pm. The compound is remarkably soluble in acetonitrile, water, and alcohols, and slightly soluble in benzene, dimethyl ether, and diethyl ether. The solutions were studied by (1)H, (13)C, (19)F, and (31)P NMR spectroscopy. The hygroscopic Me(4)PF forms a tetrahydrate which crystallizes in the space group I4(1)/a with a = 1106.1(1) pm, c = 816.3(1) pm, and Z = 4. The fluoride ion in Me(4)PF.4 H(2)O is surrounded by four water molecules. These units form a three-dimensional network in which the Me(4)P+ cations are embedded without any contacts.
Hexokinase, Jack-of-All-Trades
2003-04-10

Certain enzymes have dual functions having both catalytic and signaling activities. To this group can now be added plant hexokinases, as [Frommer and colleagues][1] discuss in their Perspective. Elegant work with Arabidopsis mutants reveals that plant hexokinases not only phosphorylate glucose but also sense glucose levels and participate in the glucose signaling pathway. [1]: http://www.sciencemag.org/cgi/content/full/300/5617/261
Muscle fibres and cultured muscle cells express the B7.1/2-related inducible co-stimulatory molecule, ICOSL: implications for the pathogenesis of inflammatory myopathies
2003-04-10

Inducible co-stimulator ligand (ICOSL), a member of the B7 family of co-stimulatory molecules related to B7.1/2, regulates CD4 as well as CD8 T-cell responses via interaction with its receptor ICOS on activated T cells. Here we examined the expression and the functional relevance of ICOSL in human muscle cells in vivo and in vitro. We investigated 25 muscle biopsy specimens from patients with polymyositis, dermatomyositis, inclusion body myositis, Duchenne muscular dystrophy and non-myopathic controls for ICOSL expression by immunohistochemistry. Normal muscle fibres constitutively express low levels of ICOSL. However, ICOSL expression is markedly increased in muscle fibres in inflammatory myopathies. Cell surface staining was most prominent in the contact areas between muscle fibres and inflammatory cells, which in turn show expression of ICOS as a marker of T-cell activation. Muscle endothelial cells show constitutive expression of ICOSL under normal and pathological conditions. We also detected mRNA and cell surface protein expression of ICOSL on myoblasts cultured from control subjects and patients as well as in TE671 muscle rhabdomyosarcoma cells. ICOSL expression was upregulated by tumour necrosis factor-alpha (TNF-alpha), whereas interferon-gamma (IFN-gamma) had no such effect. Co-culture experiments of major histocompatibility complex (MHC) class II-positive myoblasts with CD4 T cells together with superantigen demonstrated that the expression of muscle-related ICOSL has functional consequences: the production of Th1 (IFN-gamma) and Th2 cytokines [interleukin (IL)-4 and IL-10] by CD4 T cells was markedly reduced in the presence of a neutralizing anti-ICOSL monoclonal antibody (mAb HIL-131), thus showing the importance of ICOSL co-stimulation for T-cell activation. Taken together, our results demonstrate that human muscle cells express ICOSL, a functional co-stimulatory molecule distinct from B7.1 and B7.2. ICOSL-ICOS interactions may play an important role in inflammatory myopathies, providing further evidence for the antigen-presenting capacity of muscle cells.
Solvent Isotope Effect on the Reaction Catalysed by the Pyruvate Dehydrogenase Complex from Escherichia coli
2003-04-10

Abstract The pyruvate dehydrogenase from Escherichia coli showed a primary kinetic isotope effect when its overall reaction or the partial reaction of the pyruvate dehydrogenase component were tested in deuterium oxide. The Michaelis constants for pyruvate were nearly unchanged, but the maximum velocities in water and deuterium oxide differed, their ratio being DV = 1.7 for the overall reaction and DV = 2.1 for the E1p reaction. The pH profile and, accordingly, the δpK1 and δpK2 values were shifted by 0.6 units to higher pL values. A linear proton inventory curve was obtained when varying the atom fractions of protons relative to deuterons from 100 to 0%. This is an indication for a single proton transfer. It is proposed that this relatively weak primary isotope effect may be caused by the protonation of the N1 nitrogen at the pyrimidine ring of the cofactor by an adjacent glutamate residue. The proton of its carboxylic group exchanges very fast with deuterons of the solvent.
Structure and Mathematical Modelling
2003-04-10

This chapter contains sections titled: Decagon clusters in perfect and random decagonal structures Introduction The framework of cluster coverings Random cluster covering model Unit-cluster approach for Penrose-type structures Summary Coverings in the structure of quasicrystals Introduction: Geometric concepts in the structure of quasicrystals Tiling models and the triangle tiling From tiling to covering Windows for the Delone covering of the Δ tiling Colouring the tiles in the triangle tiling Covering for icosahedral tilings Summary Wavelets in the structure and physics of quasicrystals Introduction Haar wavelets for dyadic and Fibonacci tilings Haar wavelets on the triangle and the Penrose tiling Haar wavelets for the icosahedral Danzer tiling From Haar wavelets to differentiable spline wavelets Summary and future applications of quasiperiodic wavelets The surface structure of i-Al-Pd-Mn, a modeling approach Introduction Experiment Geometric model for the atomic positions Discussion Conclusion Structural order of decagonal phases at temperatures up to 1000 °C Introduction and aims Experimental Transient ordering states Domain models Superlattice formation in d-Al70+xCoyNi30–x–y Long-range fluctuations One-dimensional superstructure along the periodic direction Conclusions Combinatorial problems of (quasi-)crystallography Introduction Counting general sublattices Counting similarity sublattices Counting coincidence sublattices Central shelling Averaged shelling Other combinatorial questions Open problems Delone dynamical systems: Ergodic features and applications Introduction Delone sets and Delone dynamical systems Ergodic and combinatorial features of DDS The associated algebras and operators The integrated density of states and Shubins trace formula Conclusion Which distributions of matter diffract? – Some answers Introduction Mathematical diffraction theory Model sets Lattice substitution systems Paperfolding sequence as model set Systems with disorder Outlook
The cranial osteology of the ichthyosaurLeptonectescf.tenuirostrisfrom the Lower Jurassic of England
2003-04-11

Abstract For the first time, a three-dimensionally preserved skull of the Lower Jurassic leptonectid ichthyosaur Leptonectes cf. tenuirostris is described. The specimen reveals a wealth of new data on the cranial anatomy of basal leptonectid neoichthyosaurs. The osteology of the skull roof differs fundamentally from other well-known post-Triassic ichthyosaurs and is highly autapomorphic. The structure of the sclerotic ring, which is well preserved in situ, is described and it appears plausible that L. cf. tenuirostris was capable of stereoscopic vision. Inadequate description makes comparison to other leptonectids difficult. It can be demonstrated, however, that L. cf. tenuirostris is most similar to L. tenuirostris among known leptonectids. It is fundamentally different from the Upper Liassic Eurhinosaurus longirostris in the osteology of the skull roof and the size and orientation of the major skull openings, making generic distinction of these two species a necessity. At the moment, no autapomorphies are known of the genus Leptonectes, which therefore must be considered as a metataxon that comprises basal leptonectids from the Lower to Middle Liassic.
Laser-scanning endoscope with enhanced attributes
2003-04-11

Contemporary methods for minimally invasive interventions are gaining wide acceptance in various everyday operations, offering extremely localised treatment, reduced suffering and practically no risk for the patient as well as great benefits to diagnostic examinations and surgeries that require continuous monitoring. Many established endoscope systems offer the aforementioned advantages without the risks and restrictions of the computer-aided tomography techniques but with limitations in the resolution and chromatic representation provided. A microscanning specific-endoscope device has been developed aiming to provide superior resolution and chromatic representation in comparison with the above endoscopes. The key technology employed in the design of this endoscope relies on the use of tinny microelectro-mechanical silicon mirrors for the scanning of three laser beams over the target tissue area. The so-developed microscanning endoscope system provides color imaging wit h high resolution at near video rates targeting at macroendoscopy applications. The optical design and implementation of this endoscope system will be presented in this communication together with a brief description of the overall endoscope device developed. In addition results are given from the study of the metamery effect that is utilised in the realised endoscope, together with a presentation of the procedure followed for the objective evaluation of its optical performance and first results from system operation.
Expression and Regulation of the Na+‐K+‐2Cl− Cotransporter NKCC1 in the Normal and CFTR‐Deficient Murine Colon
2003-04-15

Defective regulation and/or reduced expression of the Na + ‐K + ‐2Cl − cotransporter NKCC1 may contribute to the severe secretory defect that is observed in cystic fibrosis, but data concerning the expression and function of NKCC1 in cystic fibrosis transmembrane conductance regulator (CFTR)‐deficient cells are equivocal. We therefore investigated NKCC1 mRNA expression, Na + ‐K + ‐2Cl − cotransport activity and regulation by cAMP in crypts isolated from the proximal colon of CFTR‐containing (CFTR (+/+)) and CFTR‐deficient (CFTR (−/−)) mice. mRNA expression levels were determined by semiquantitative PCR, transport rates were measured fluorometrically in 2′,7′‐bis(carboxyethyl)‐5(6)‐carboxyfluorescein acetomethylester (BCECF)‐loaded crypts, cytoplasmic volume changes were assessed by confocal microscopy, and [Cl − ] i changes were examined by N ‐(ethoxycarbonylmethyl)‐6‐methoxyquinolinium bromide (MQAE) quenching. NKCC1 mRNA expression levels were not significantly reduced in CFTR (−/−) crypts compared to controls. Azosemide‐sensitive NH 4 + influx (used as a measure of Na + ‐K + ‐2Cl − cotransport) was 2.23 ± 0.72 vs . 1.56 ± 0.16 m m min −1 , and increased by 63.6 % in (+/+) and 87.3 % in (−/−) crypts upon stimulation for 5 min with forskolin. After 20 min of stimulation with forskolin, the Na + ‐K + ‐2Cl − cotransport rates in (−/−) and (+/+) crypts were identical. Crypt cross‐sectional area and [Cl − ] i decreased only in (+/+) crypts upon stimulation. In conclusion, normal NKCC1 expression levels, somewhat reduced Na + ‐K + ‐2Cl − cotransport rates, but preserved activation by cAMP were found in colonic crypts from CFTR (−/−) mice, ruling out a severe dysfunction of the Na + ‐K + ‐2Cl − cotransporter in the CF intestine. Furthermore, these studies establish the existence of a direct, cell‐volume‐ and [Cl − ] i ‐independent activation of colonic NKCC1 by an increase in intracellular cAMP.
Conjugated Molecules for the Smart Filtering of Intense Radiations
2003-04-15

The practical realization of smart optical filters, i.e. devices which change their optical transmission in a suitable way to keep a working state for a general light sensitive element , can involve the use of conjugated molecules whose light absorption properties are light- intensity dependent (nonlinear optical effect). The verification of optical limiting displayed by some particular conjugated molecules, e.g. phthalocyanines, is quite noteworthy and can be successfully exploited for the realization of such smart optical devices. In the present contribution the analysis of the relevant molecular feature of a phthalocyanine are analyzed with the aim of determining useful correlations between optical limiting performance and phthalocyanine chemical structure. In particular , the electronic nature of the substituent is considered as a key factor for the explanation of some observed optical limiting trends.
Paleolithic burnt bone horizons from the Swabian Jura: Distinguishing between in situ fireplaces and dumping areas
2003-04-16

Abstract Hohle Fels Cave is one of several Upper Paleolithic sites on the eastern extension of the Swabian Alb in southwestern Germany. Several phases of excavations have been conducted since 1870. The archaeological inventories comprise a broad range of artifacts produced from stone, bone, teeth, ivory, and antler. The site has also yielded Paleolithic rock art, sculpture, and engravings. The Pleistocene inventories unearthed so far belong to the Magdalenian, Gravettian, and Aurignacian; Middle Paleolithic horizons may well be uncovered as excavations continue. The chronology of three main occupation phases has been established with numerous 14 C measurements. The Magdalenian dates to about 13,000 yr B.P., and the richest Gravettian deposit contains a burnt bone‐layer extending over ca. 12 m 2 that dates to about 29,000 yr B.P. The underlying Aurignacian horizons predate 30,000 yr B.P. The Gravettian burnt bone layer (archaeological layer IIcf) is a key horizon because of its distinct composition and color and its large horizontal extension. Layer IIcf has been examined using a combination of analytical techniques including micromorphological analysis of thin sections with polarizing light microscopy and scanning electron microscopy for fabric and identification of mineral and biogenic constituents. The bone mineral composition was analyzed by Fourier transform infrared spectroscopy (FTIR) and electron probe microanalytical techniques. These investigations in tandem with the field observations indicate intense burning of bones as fuel. The micromorphological and contextual archaeological data suggest that layer IIcf is a secondary dump rather than an in situ accumulation. This deposit and other Paleolithic burnt deposits in the Swabian Jura appear to reflect intense periods of winter occupation in these caves. © 2003 Wiley Periodicals, Inc.