Extramedullary expansion of hematopoietic progenitor cells in interleukin (IL)-6-sIL-6R double transgenic mice

Soluble cytokine receptors modulate the activity of their cognate ligands. Interleukin (IL)-6 in association with the soluble IL-6 receptor (sIL-6R) can activate cells expressing the gp130 signal transducer lacking the specific IL-6R. To investigate the function of the IL-6-sIL-6R complex in vivo and to discriminate the function of the IL-6-sIL-6R complex from the function of IL-6 alone, we have established a transgenic mouse model. Double-transgenic mice coexpressing IL-6 and sIL-6R were generated and compared with IL-6 and sIL-6R single-transgenic mice. The main phenotype found in IL-6-sIL-6R mice was a dramatic increase of extramedullary hematopoietic progenitor cells in liver and spleen but not in the bone marrow. In IL-6 single-transgenic mice and sIL-6R single-transgenic mice no such effects were observed. The high numbers of hematopoietic progenitor cells were reflected by a strong increase of peripheral blood cell numbers. Therefore, activators of the gp130 signal transducer like the IL-6-IL-6R complex may represent most powerful stimulators for extramedullary hematopoietic progenitor cells. gp130 activators may become important for the expansion of hematopoietic progenitor cells in vivo and in vitro.     

Photon echoes and combination tones--A comparison between their polarization dependence

The effects of level degeneracy on the polarization dependence of photon echoes and of combination tones in gases are compared. A remarkable similarity in behavior is found to exists, with quantitative agreement in the case of several simple transitions. By analogy, the echo behavior for elliptically polarized input pulses is suggested.     

The quantitative humoral immune response to the hepatitis C virus is correlated with disease activity and response to interferon-alpha

BACKGROUND/AIM: Virus-host interactions may have pathogenetic significance in chronic hepatitis. Thus the humoral immune response was evaluated during the clinical course of HCV-infected patients. METHODS: Eighteen selected chronic HCV patients received three doses of 3 or 6 MU interferon-alpha 2a weekly for 6 to 12 months and were followed up for 6 to 60 months. Anti-HCV antibody levels were serially measured either in end-point diluted sera with the Matrix-Assay or with quantitative anti-HC34-IgG and -IgM ELISA. Circulating immune complexes were assessed by flow cytometry and the results were correlated with histology, quantitative HCV-RNA levels and genotypes. RESULTS: Nine complete responders (CR; genotypes 1a n = 4; 1b n = 1; 2a n = 1; 3a n = 3) showing sustained virus elimination and ALT normalisation had low HCV-RNA pretreatment levels (mean 14 x 10(3) copies/ml) compared to six nonresponders and three partial responders (NR/PR; genotypes 1a n = 2; 1b n = 7) who had significantly higher HCV-RNA pretreatment levels (mean 254 x 10(3) copies/ml; p < 0.01). In untreated NR/PR the HC34 core-antigen was most immunogenic, in CR the NS3-derived HC29-antigen. Pre-treatment levels of anti-HC 34-IgG and -IgM antibody levels in NR/PR were higher than in CR (IgM/IgG p = 0.05, n.s.) and these differences became significant during or after therapy (3 months therapy: IgM p < 0.02/IgG p < 0.07; end of therapy: IgM 0.006/IgG p < 0.04; 6 months post-therapy: IgM p < 0.002/IgG p < 0.004). The PR patients showed recurrent anti-HC34 antibody levels that preceded disease reactivation and detectable HCV-RNA in serum. Immune complex formation increased in some patients during treatment but did not correlate with disease activity, quantitative viraemia, antibody levels or therapy outcome. CONCLUSION: Anti-HC34 antibodies, i.e. of the IgM-subtype, correlated quantitatively with viraemia and disease activity. Monitoring the antibody levels may predict the long-term therapy outcome during interferon-alpha treatment.     

Role of specific instances in controlling a dynamic system.

This article examines the claim that the learning of a dynamic control task is mediated by a lookup table consisting of previously successful trials on the task. Consistent with the predictions of a lookup table, in 2 experiments participants tended to give the same response to situations in which they had previously been successful rather than unsuccessful. Further, in both experiments, participants' knowledge did not generalize to new dissimilar situations, unless the dynamic control task was governed by a highly salient rule. A version of G. Logan's (1988) instance theory, which assumes that participants store each successful response as a separate instance linking the situation to the response, was able to quantitatively match a range of measures of participants' performance with 1 free parameter, except in the case in which the control task was governed by a salient rule. In a complementary way, an alternative rule-based model could only match participants' performance when the control task was governed by a highly salient rule. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cross-phase modulation in a semiconductor laser amplifierdetermined by a dispersive technique

Cross-phase modulation in a semiconductor laser diode amplifier is reported. A simple expression for the chirp imparted on a weak signal pulse by the action of a strong pump pulse is derived. A novel dispersive technique for characterizing the resulting nonlinear chirp is introduced and used in the present experiment. A maximum frequency excursion of 16 GHz, due to the cross-phase modulation, was measured. A value of 6 was found for α_xpm, which is a factor for characterizing the cross-phase modulation in a similar manner to the conventional linewidth enhancement factor α     

A discussion of material rotation and stress rate

Summary Characterization of material behavior can be divided into two parts, the analysis of deformation and the underlying physics, though these are intimately related. A significant advance in the analysis of deformation was made when the polar decomposition theorem was introduced, making it possible to separate large deformations into a stretch and a rotation. Consequences of the theorem affect the way rate processes should be characterized. In particular, rate of material rotation is different from vorticity, and the stress rate for finite strains is different from the usual stress rate of Zaremba, Jaumann, and Noll. It is convenient to define a strain rate that is different from the stretching that is the symmetric part of the velocity gradient. These concepts are described in detail in a 1979 paper. Various criticisms of that paper have appeared in the Journal of Applied Mechanics, which are discussed herein. To illustrate the distinction it is shown that the rate of rotation in a classical vortex does not vanish, though the vorticity is zero. It is also shown that the rate of material rotation recently computed by Nemat-Nasser, which involves an eigenvalue expansion, is equivalent to the one given in the 1979 paper, which makes use of matrix inversion, and it is asseverated that the matrix inversion approach is computationally more efficient.     

Intracellular accumulation of incompletely processed transforming growth factor-alpha polypeptides in ground glass hepatocytes of chronic hepatitis B virus infection

BACKGROUND: Transforming growth factor-alpha is an intracellularly processed and secreted polypeptide that induces a proliferative response in epithelial target cells and represents a potential regulatory factor in embryonic development, liver regeneration, and also hepatocarcinogenesis. We have observed focal transforming growth factor-alpha expression in liver tissues with chronic hepatitis B virus infection. METHODS: To further elucidate the nature of this focal transforming growth factor-alpha accumulation we have analyzed overall 23 different liver tissues with chronic hepatitis B virus and hepatitis C virus infection as well as normal liver tissues by immunohistology, ELISA, and Western immunoblot with and without immunoprecipitation. RESULTS: By immunohistology transforming growth factor-alpha polypeptides showed focal subcellular accumulation in ground glass hepatocytes, the histological hallmark of chronic hepatitis B virus infection, in co-localization with HBV-preS1 antigen. By ELISA and Western immunoblot increased tissue concentrations of transforming growth factor-alpha were demonstrated in chronically hepatitis B virus-infected liver tissues with ground glass hepatocytes, especially a 15-kD polypeptide, most likely representing an incompletely processed transforming growth factor-alpha polypeptide. Transforming growth factor-alpha retention in ground glass hepatocytes is not a general unspecific effect, since it was not observed for several other secretory liver proteins. Accumulated transforming growth factor-alpha in ground glass hepatocytes does not co-localize with Epidermal Growth Factor Receptor expression. CONCLUSION: Thus evidence is presented that a principally secreted (viral) polypeptide (HBV-preS1) can interfere with the secretion and processing of a second (cellular) protein (transforming growth factor-alpha). Accumulation of transforming growth factor-alpha may result from alteration of the endoplasmic reticulum due to storage of hepatitis B virus surface antigen particles. No evidence was found for transforming growth factor-alpha in ground glass hepatocytes to intracellularly interact with the Epidermal Growth Factor Receptor.     

On the analysis of rotation and stress rate in deforming bodies

Summary When a solid element experience large deformations, the components of stress will, in general, vary as a result of material rotation. These changes occur even in the absence of additional strain, and need to be accounted for in formulating constitutive laws that involve the rate of change of stress. In this paper the correction terms are extended to the case when material axes become strongly skewed. An expression for the rate of material rotation as an explicit function of vorticity, rate of deformation and stretch is derived. It is then shown that the rate of change of stress depends on the rate of material rotation. As an example, expressions for material rotation and stress are derived for a hypoelastic material undergoing uniform, rectilinear, shear. The shear stress is compared with a solution that neglects skewing of the axes, and it is found that, for the example, skewing may be neglected for strains less than 0.4. Finally, the use of these relations in numerical calculations involving finite deformation is discussed.

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Zur Untersuchung der Rotations-und Spannungsgeschwindigkeit in sich deformierenden Körpern

Zusammenfassung Wenn ein Festkörper große Verformungen erfährt, werden sich die Spannungskomponenten im allgemeinen als Folge der Materialrotation ändern. Diese Veränderungen treten sogar in Abwesenheit zusätzlicher Verzerrung auf, und müssen bei der Formulierung der Zustandsgleichungen, welche die Rate der Spannungsänderung berücksichtigen, in Betracht gezogen werden. In dieser Arbeit werden die Korrekturglieder erweitert zu dem Fall, wenn die materialachsen stark schräg zueinander werden. Abgeleitet wird ein Ausdruck für die Werkstoffrotationsgeschwindigkeit als eine explizite Funktion der Wirbel, Verformungs-und Ausdehnungsgeschwindigkeit. Es wird dann gezeigt, daß die Änderung der Spannung von der Materialrotationsgeschwindigkeit abhängig ist. Als Beispiel werden Ausdrücke für Werkstoffrotation und Spannung für einen hypo-elastischen Werkstoff, der gleichförmigen, geradlinigen Schub aufweist, hergeleitet. Die Schubspannung wird mit einer Lösung verglichen, die die Schräge der Achsen vernachlässigt, und es ergibt sich, daß, für dieses Beispiel, die Schräge für Verzerrungen weniger als 0,4 zu vernachlässigen ist. Abschließend wird die Anwendung dieser Beziehungen in numerischen Rechnungen für endliche Deformationen erörtert.

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With 1 Figure