Intrinsic Features (intrinsic + feature)

Distribution by Scientific Domains

Selected Abstracts

Comparison of bone marrow and peripheral blood ZAP-70 status examined by flow cytometric immunophenotyping in patients with chronic lymphocytic leukemia

CYTOMETRY, Issue 4 2006
Rachel Sheridan
Abstract Background: The mutational status of the immunoglobulin heavy chain variable gene in patients with chronic lymphocytic leukemia correlates with prognosis. Patients with mutated IgVH genes fare better than those with unmutated genes. Gene expression profiling studies identified the tyrosine kinase ZAP-70 to be expressed in unmutated CLL samples. Flow cytometric examination of ZAP-70 expression in tumor cells has been proposed to be a convenient surrogate marker for IgVH mutational status. However, a few studies have shown a small number of discordant results between ZAP-70 positivity, IgVH mutational status, and clinical outcome. There have been no reported studies comparing bone marrow samples with peripheral blood for ZAP-70 expression in CLL patients. Methods: We searched our flow cytometry files from October 2004 through April 2006 and identified CLL in 311 bone marrow and peripheral blood specimens from 256 patients. We defined ZAP-70 positivity as greater than 30% of the CD19+ B-cells above the isotype control value that coexpress ZAP-70. Statistical analyses were performed using the Fisher exact test and student t -test. Results: A significantly greater number of bone marrow specimens were positive for ZAP-70 when compared with the number of peripheral blood specimens. Of all the ZAP-70 negative specimens, CLL cells from bone marrow had a greater mean percentage of ZAP-70 positive cells when compared with the CLL cells from peripheral blood. Finally, six patients were identified who were ZAP-70 positive in the bone marrow but ZAP-70 negative in the peripheral blood. Conclusions: These results may be due to either an increase in the false positive rate in bone marrow specimens or to an intrinsic feature of CLL cells in the compartment that is biologically distinct from peripheral tumor cells. As prognosis and treatment decisions may be based on ZAP-70 results from either specimen type, it is prudent to further examine this observation. © 2006 International Society for Analytical Cytology [source]

Unexpected complexity of the budding yeast transcriptome

IUBMB LIFE, Issue 12 2008
Takashi Ito
Abstract The genome of the budding yeast Saccharomyces cerevisiae was sequenced over a decade ago and has been annotated to encode ,6,000 genes. However, recent high throughput studies using tiling array hybridization and cDNA sequencing have revealed an unexpectedly large number of previously undescribed transcripts. They largely lack protein-coding capacity and are transcribed from both strands of intragenic and intergenic regions in the genome. Accordingly, pervasive transcription leading to a plethora of noncoding RNAs, which was first revealed for mammalian genomes to attract intense attentions, is likely an intrinsic feature of eukaryotic genomes. Although it is not clear what fraction of these transcription events are functional, some were shown to induce transcriptional interference or histone modifications to regulate gene expression. The budding yeast may serve as an excellent model to study pervasive transcription and noncoding RNAs. © 2008 IUBMB IUBMB Life, 60(12): 775,781, 2008 [source]

Independent association of rheumatoid arthritis with increased left ventricular mass but not with reduced ejection fraction

Rebecca L. Rudominer
Objective Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with premature atherosclerosis, vascular stiffening, and heart failure. This study was undertaken to investigate whether RA is associated with underlying structural and functional abnormalities of the left ventricle (LV). Methods Eighty-nine RA patients without clinical cardiovascular disease and 89 healthy matched controls underwent echocardiography, carotid ultrasonography, and radial tonometry to measure arterial stiffness. RA patients and controls were similar in body size, hypertension and diabetes status, and cholesterol level. Results LV diastolic diameter (4.92 cm versus 4.64 cm; P < 0.001), mass (136.9 gm versus 121.7 gm; P = 0.004 or 36.5 versus 32.9 gm/m2.7; P = 0.01), ejection fraction (71% versus 67%; P < 0.001), and prevalence of LV hypertrophy (18% versus 6.7%; P = 0.023) were all higher among RA patients versus controls. In multivariate analysis, presence of RA was an independent correlate of LV mass (P = 0.004). Furthermore, RA was independently associated with presence of LV hypertrophy (odds ratio 4.14 [95% confidence interval 1.24, 13.80], P = 0.021). Among RA patients, age at diagnosis and disease duration were independently related to LV mass. RA patients with LV hypertrophy were older and had higher systolic pressure, damage index scores, C-reactive protein levels, homocysteine levels, and arterial stiffness compared with those without LV hypertrophy. Conclusion The present results demonstrate that RA is associated with increased LV mass. Disease duration is independently related to increased LV mass, suggesting a pathophysiologic link between chronic inflammation and LV hypertrophy. In contrast, LV systolic function is preserved in RA patients, indicating that systolic dysfunction is not an intrinsic feature of RA. [source]

The cause of superchrons

J A Jacobs
Superchrons , long periods in the geomagnetic record when the Earth's magnetic field did not reverse its polarity , are a challenge to observers and theorists. Jack Jacobs outlines the problems and some possible solutions. Reversals of polarity are a feature of the geomagnetic record for all the time it has been documented. Although not regular, reversals are sufficiently frequent for their absence to be noticeable. When the Earth's magnetic field retains the same polarity for over 20 million years, a superchron is established. Superchrons demand the attention of geophysicists concerned with the generation of the Earth's field: either they must result from an intrinsic feature of the geodynamo, or they reflect the influence of some external force. Here I discuss internal and external mechanisms for the formation of superchrons, including the role of the inner core, true polar wander, Earth's orbital variations and tides. [source]

Influence of Growth Temperature and Carrier Flux on the Structure and Transport Properties of Highly Oriented CrO2 on Al2O3 (0001),

M. Sousa
Abstract In this work we report on the structure and magnetic and electrical transport properties of CrO2 films deposited onto (0001) sapphire by atmospheric pressure (AP)CVD from a CrO3 precursor. Films are grown within a broad range of deposition temperatures, from 320 to 410,°C, and oxygen carrier gas flow rates of 50,500,sccm, showing that it is viable to grow highly oriented a -axis CrO2 films at temperatures as low as 330,°C i.e., 60,70,°C lower than is reported in published data for the same chemical system. Depending on the experimental conditions, growth kinetic regimes dominated either by surface reaction or by mass-transport mechanisms are identified. The growth of a Cr2O3 interfacial layer as an intrinsic feature of the deposition process is studied and discussed. Films synthesized at 330,°C keep the same high quality magnetic and transport properties as those deposited at higher temperatures. [source]

Deforming DNA: From Physics to Biology

CHEMPHYSCHEM, Issue 9-10 2009
Chantal Prévost Dr.
Abstract DNA molecules do the twist: The DNA double helix is a remarkably adaptable molecule that can undergo major conformational rearrangements without being irreversibly damaged. Indeed, DNA deformation is an intrinsic feature of many biological processes. In this Minireview, the authors summarize recent advances in the study of DNA deformation. The picture shows five different conformations of the double helix of DNA. The DNA double helix has become a modern icon which symbolizes our understanding of the molecular basis of life. It is less widely recognized that the double helix proposed by Watson and Crick more than half a century ago is a remarkably adaptable molecule that can undergo major conformational rearrangements without being irreversibly damaged. Indeed, DNA deformation is an intrinsic feature of many of the biological processes in which it is involved. Over the last two decades, single-molecule experiments coupled with molecular modeling have transformed our understanding of DNA flexibility, while the accumulation of high-resolution structures of DNA,protein complexes have demonstrated how organisms can exploit this property as a useful feature for preserving, reading, replicating, and packaging the genetic message. In this Minireview we summarize the information now available on the extreme,and the less extreme,deformations of the double helix. [source]

Movement trajectories and habitat partitioning of small mammals in logged and unlogged rain forests on Borneo

Summary 1Non-volant animals in tropical rain forests differ in their ability to exploit the habitat above the forest floor and also in their response to habitat variability. It is predicted that specific movement trajectories are determined both by intrinsic factors such as ecological specialization, morphology and body size and by structural features of the surrounding habitat such as undergrowth and availability of supportive structures. 2We applied spool-and-line tracking in order to describe movement trajectories and habitat segregation of eight species of small mammals from an assemblage of Muridae, Tupaiidae and Sciuridae in the rain forest of Borneo where we followed a total of 13 525 m path. We also analysed specific changes in the movement patterns of the small mammals in relation to habitat stratification between logged and unlogged forests. Variables related to climbing activity of the tracked species as well as the supportive structures of the vegetation and undergrowth density were measured along their tracks. 3Movement patterns of the small mammals differed significantly between species. Most similarities were found in congeneric species that converged strongly in body size and morphology. All species were affected in their movement patterns by the altered forest structure in logged forests with most differences found in Leopoldamys sabanus. However, the large proportions of short step lengths found in all species for both forest types and similar path tortuosity suggest that the main movement strategies of the small mammals were not influenced by logging but comprised generally a response to the heterogeneous habitat as opposed to random movement strategies predicted for homogeneous environments. 4Overall shifts in microhabitat use showed no coherent trend among species. Multivariate (principal component) analysis revealed contrasting trends for convergent species, in particular for Maxomys rajah and M. surifer as well as for Tupaia longipes and T. tana, suggesting that each species was uniquely affected in its movement trajectories by a multiple set of environmental and intrinsic features. [source]

Omnidirectional Vision and Inertial Clues for Robot Navigation

Irem Stratmann
The structural features inherent in the visual motion field of a mobile robot contain useful clues about its navigation. The combination of these visual clues and additional inertial sensor information may allow reliable detection of the navigation direction for a mobile robot and also the independent motion that might be present in the 3D scene. The motion field, which is the 2D projection of the 3D scene variations induced by the camera-robot system, is estimated through optical flow calculations. The singular points of the global optical flow field of omnidirectional image sequences indicate the translational direction of the robot as well as the deviation from its planned path. It is also possible to detect motion patterns of near obstacles or independently moving objects of the scene. In this paper, we introduce the analysis of the intrinsic features of the omnidirectional motion fields, in combination with gyroscopical information, and give some examples of this preliminary analysis. © 2004 Wiley Periodicals, Inc. [source]

IN FOCUS: Activation of platelets by heparin-induced thrombocytopenia antibodies in the serotonin release assay is not dependent on the presence of heparin

Summary., The serotonin release assay (SRA) tests for antibodies responsible for heparin-induced thrombocytopenia (HIT). By definition, SRA-positive antibodies cause platelet serotonin release in vitro, in the presence of low concentrations of heparin, but not with excess heparin. Many SRA-positive sera activate platelets in the presence of saline without drug, either as a result of residual heparin in the specimen, or because of intrinsic features of the HIT antibodies. The present experiments show that neither exhaustive heparinase treatment, nor chromatographic removal of heparin abrogates the spontaneous platelet activation caused by these HIT antibodies. This is the first study to systematically demonstrate that in vitro activity of HIT antibodies can be independent of heparin. In addition, T-gel chromatography demonstrated differences among fractions of enzyme-linked-immunosorbent assay (ELISA)-positive HIT antibodies within individual specimens. Certain ELISA-positive fractions had SRA activity while others did not, and the SRA activity was not proportional to HIT antibody ELISA titer. These data suggest that antibodies formed as a result of heparin treatment are heterogeneous, and that some can contribute to the pathogenesis of HIT even when heparin is no longer present. [source]

NMR characterization of new 10-membered-ring macrolactones and dihydrobenzophenazine-5-one, oxidized derivatives of benzo[a]phenazines

Marília O. F. Goulart
Abstract Peroxidation of the phenazine of ,-lapachone using m -ClC6H4CO3HCH2Cl2 furnished a macrolactone with a rigid 10-membered ring, and the corresponding N -oxide, along with a dihydrobenzophenazine-5-one. All of the new compounds were fully characterized by spectroscopic methods, with the unambiguous assignment of the hydrogens and carbon NMR signals for the N -oxide, with the aid of 2-D NMR, mainly COSY, HMQC, HSQC and HMBC. For the other two compounds some signals could not be assigned owing to their own intrinsic features. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Grip force abnormalities in de novo Parkinson's disease

Stuart J. Fellows PhD
Abstract In recent years it has been shown that a variety of movement disorders are associated with abnormalities of the fine motor control of the hand. In Parkinson's disease (PD), these changes consist of a slowing of the rate of grip force development and the use of abnormally large grip forces both during lifting and static holding of an object. It has been suggested, however, that these changes are a direct effect of the patient's levodopa medication or associated with levodopa induced dyskinesias. Accordingly, we examined the performance of de novo Parkinson patients in a precision lifting task. All patients (n = 6) were newly diagnosed and showed rigidity, bradykinesia, or both, but were unaffected by tremor or dyskinesia. None of the patients had received antiparkinson medication. Grip force was abnormally high in both the lifting and hold phases. This exaggeration was equal in magnitude to that observed previously in medicated patients. Thus we conclude that the abnormalities in grip force observed here are intrinsic features of PD and not the result of dopamine medication or its side effects. © 2004 Movement Disorder Society [source]

II,Reflections on the Reasonable and the Rational in Conflict Resolution

Ruth Chang
Most familiar approaches to social conflict moot reasonable ways of dealing with conflict, ways that aim to serve values such as legitimacy, justice, morality, fairness, fidelity to individual preferences, and so on. In this paper, I explore an alternative approach to social conflict that contrasts with the leading approaches of Rawlsians, perfectionists, and social choice theorists. The proposed approach takes intrinsic features of the conflict,what I call a conflict's evaluative ,structure',as grounds for a rational way of responding to that conflict. Like conflict within a single person, social conflict can have a distinctive evaluative structure that supports certain rational responses over others. I suggest that one common structure in both intra- and interpersonal cases of conflict supports the rational response of ,self-governance'. Self-governance in the case of social conflict involves a society's deliberating over the question, ,What kind of society should we be?' In liberal democracies, this rational response is also a reasonable one. [source]

Structural and thermodynamic encoding in the sequence of rat microsomal cytochrome b5,

BIOPOLYMERS, Issue 5 2008
Juliette T. J. Lecomte
Abstract The water-soluble domain of rat microsomal cytochrome b5 is a convenient protein with which to inspect the connection between amino acid sequence and thermodynamic properties. In the absence of its single heme cofactor, cytochrome b5 contains a partially folded stretch of ,30 residues. This region is recognized as prone to disorder by programs that analyze primary structures for such intrinsic features. The cytochrome was subjected to amino acid replacements in the folded core (I12A), in the portion that refolds only when in contact with the heme group (N57P), and in both (F35H/H39A/L46Y). Despite the difficulties associated with measuring thermodynamic quantities for the heme-bound species, it was possible to rationalize the energetic consequences of both types of replacements and test a simple equation relating apoprotein and holoprotein stability. In addition, a phenomenological relationship between the change in Tm (the temperature at the midpoint of the thermal transition) and the change in thermodynamic stability determined by chemical denaturation was observed that could be used to extend the interpretation of incomplete holoprotein stability data. Structural information was obtained by nuclear magnetic resonance spectroscopy toward an atomic-level analysis of the effects. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 428,442, 2008. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at [source]

Message Properties, Mediating States, and Manipulation Checks: Claims, Evidence, and Data Analysis in Experimental Persuasive Message Effects Research

Daniel J. O'Keefe
This article addresses the conceptualization and definition of message variables in persuasion effects research. Two central claims are advanced. First, effect-based message variable definitions (in which a message variation is defined in terms of effects on psychological states, as when fear appeal variations are defined on the basis of differences in aroused fear) impede progress in understanding persuasion processes and effects and hence should be avoided in favor of definitions expressed in terms of intrinsic message features. Second, when message variations are defined in terms of intrinsic features, message manipulation checks, under that description, are unnecessary but similar measures may usefully be understood and analyzed as assessments of potential mediating states. [source]