Free propagation phase-contrast breast CT provides higher image quality than cone-beam breast-CT at low radiation doses: a feasibility study on human mastectomies

In this study we demonstrate the first direct comparison between synchrotron x-ray propagation-based CT (PB-CT) and cone-beam breast-CT (CB-CT) on human mastectomy specimens (N = 12) including different benign and malignant lesions. The image quality and diagnostic power of the obtained data sets were compared and judged by two independent expert radiologists. Two cases are presented in detail in this paper including a comparison with the corresponding histological evaluation. Results indicate that with PB-CT it is possible to increase the level of contrast-to-noise ratio (CNR) keeping the same level of dose used for the CB-CT or achieve the same level of CNR reached by CB-CT at a lower level of dose. In other words, PB-CT can achieve a higher diagnostic potential compared to the commercial breast-CT system while also delivering a considerably lower mean glandular dose. Therefore, we believe that PB-CT technique, if translated to a clinical setting, could have a significant impact in improving breast cancer diagnosis.

Synthetic Cargo Internalization Receptor System for Nanoparticle Tracking of Individual Cell Populations by Fluorine Magnetic Resonance Imaging

Specific detection of target structures or cells lacking particular surface epitopes still poses a serious problem for all imaging modalities. Here, we demonstrate the capability of synthetic "cargo internalization receptors" (CIRs) for tracking of individual cell populations by ¹H/¹⁹F magnetic resonance imaging (MRI). To this end, a nanobody for green fluorescent protein (GFP) was used to engineer cell-surface-expressed CIRs which undergo rapid internalization after GFP binding. For ¹⁹F MR visibility, the GFP carrier was equipped with "contrast cargo", in that GFP was coupled to perfluorocarbon nanoemulsions (PFCs). To explore the suitability of different uptake mechanisms for this approach, CIRs were constructed by combination of the GFP nanobody and three different cytoplasmic tails that contained individual internalization motifs for endocytosis of the contrast cargo (CIR1-3). Exposure of CIR⁺ cells to GFP-PFCs resulted in highly specific binding and internalization as confirmed by fluorescence microscopy as well as flow cytometry and enabled visualization by ¹H/¹⁹F MRI. In particular, expression of CIR2/3 resulted in substantial incorporation of ¹⁹F cargo and readily enabled in vivo visualization of GFP-PFC recruitment to transplanted CIR⁺ cells by ¹H/¹⁹F MRI in mice. Competition experiments with blood immune cells revealed that CIR⁺ cells are predominantly loaded with GFP-PFCs even in the presence of cells with strong phagocytotic capacity. Importantly, binding and internalization of GFP-PFCs did not result in the activation of signaling cascades and therefore does not alter cell physiology. Overall, this approach represents a versatile in vivo imaging platform for tracking of individual cell populations by making use of cell-type-specific CIR⁺ mice.

Soluble gp130 prevents interleukin-6 and interleukin-11 cluster signaling but not intracellular autocrine responses

Interleukin-6 (IL-6) is a proinflammatory cytokine of the IL-6 family, members of which signal through a complex of a cytokine-specific receptor and the signal-transducing subunit gp130. The interaction of IL-6 with the membrane-bound IL-6 receptor (IL-6R) and gp130 stimulates “classic signaling,” whereas the binding of IL-6 and a soluble version of the IL-6R to gp130 stimulates “trans-signaling.” Alternatively, “cluster signaling” occurs when membrane-bound IL-6:IL-6R complexes on transmitter cells activate gp130 receptors on neighboring receiver cells. The soluble form of gp130 (sgp130) is a selective trans-signaling inhibitor, but it does not affect classic signaling. We demonstrated that the interaction of soluble gp130 with natural and synthetic membrane-bound IL-6:IL-6R complexes inhibited IL-6 cluster signaling. Similarly, IL-11 cluster signaling through the IL-11R to gp130 was also inhibited by soluble gp130. However, autocrine classic and trans-signaling was not inhibited by extracellular inhibitors such as sgp130 or gp130 antibodies. Together, our results suggest that autocrine IL-6 signaling may occur intracellularly.

Association between the oxidative status, Vitamin D levels and respiratory function in asthmatic children

AIM

We studied the relationship between plasma concentrations of oxidative system markers, vitamin D, and respiratory functions in children with asthma.

MATERIALS AND METHODS

Ninety one children aged 6-17 years with stable asthma seen in the clinic had the serum concentrations of oxidative system markers [total antioxidant capacity (TAC), total oxidative status (TOS), paraoxonase-1 activity (PON-1), and 25-hydroxyvitamin D3] and respiratory functions were measured.

RESULTS

There was no statistical correlation between TAC and age and FEV1. There was a significant positive correlation between TAC and 25(OH)D3 (r = 0.214, P = 0.021), TAC and TOS (r = 0.218, P = 0.007), TAC and PON-1 (r = 0.230, P = 0.028), TAC and IgE (r = 0.194, P = 0.033), and inverse correlation between TAC and PEF (r = -0.208, P = 0.024). In the backward multiple regression analysis, 25(OH)D3 (t = 2.613, P = 0.011), age (t = -2.158, P = 0.034), TOS (t = 2.158, P = 0.000), and OSI index (t = -13.859 P = 0.000) maintained an independent relationship with TAC (r = 0.858, r2 = 0.737, F = 21.436, P = 0.000).

CONCLUSION

Oxidative stress correlates with the serum vitamin D concentrations. Clinical trials are required to confirm that increasing serum 25OHD may improve asthma control, as measured by clinical and oxidative stress markers.

The balance of interleukin (IL)-6, IL-6·soluble IL-6 receptor (sIL-6R), and IL-6·sIL-6R·sgp130 complexes allows simultaneous classic and trans-signaling

Interleukin (IL-)6 is the major pro-inflammatory cytokine within the IL-6 family. IL-6 signals via glycoprotein 130 (gp130) and the membrane-bound or soluble IL-6 receptor (IL-6R), referred to as classic or trans-signaling, respectively. Whereas inflammation triggers IL-6 expression, eventually rising to nanogram/ml serum levels, soluble IL-6R (sIL-6R) and soluble gp130 (sgp130) are constitutively present in the upper nanogram/ml range. Calculations based on intermolecular affinities have suggested that systemic IL-6 is immediately trapped in IL-6·sIL-6R and IL-6·sIL-6R·sgp130 complexes, indicating that sIL-6R and sgp130 constitute a buffer system that increases the serum half-life of IL-6 or restricts systemic IL-6 signaling. However, this scenario has not been experimentally validated. Here, we quantified IL-6·sIL-6R and IL-6·sIL-6R·sgp130 complexes over a wide concentration range. The amounts of IL-6 used in this study reflect concentrations found during active inflammatory events. Our results indicated that most IL-6 is free and not complexed with sIL-6R or sgp130, indicating that the level of endogenous sgp130 in the bloodstream is not sufficient to block IL-6 trans-signaling via sIL-6R. Importantly, addition of the single-domain antibody VHH6, which specifically stabilizes IL-6·sIL-6R complexes but did not bind to IL-6 or sIL-6R alone, drove free IL-6 into IL-6·sIL-6R complexes and boosted trans-signaling but not classic signaling, demonstrating that endogenous sIL-6R has at least the potential to form complexes with IL-6. Our findings indicate that even though high concentrations of sIL-6R and sgp130 are present in human serum, the relative ratio of free IL-6 to IL-6·sIL-6R allows for simultaneous classic and trans-signaling.

Split2 Protein-Ligation Generates Active IL-6-Type Hyper-Cytokines from Inactive Precursors

Trans-signaling of the major pro- and anti-inflammatory cytokines Interleukin (IL)-6 and IL-11 has the unique feature to virtually activate all cells of the body and is critically involved in chronic inflammation and regeneration. Hyper-IL-6 and Hyper-IL-11 are single chain designer trans-signaling cytokines, in which the cytokine and soluble receptor units are trapped in one complex via a flexible peptide linker. Albeit, Hyper-cytokines are essential tools to study trans-signaling in vitro and in vivo, the superior potency of these designer cytokines are accompanied by undesirable stress responses. To enable tailor-made generation of Hyper-cytokines, we developed inactive split-cytokine-precursors adapted for posttranslational reassembly by split-intein mediated protein trans-splicing (PTS). We identified cutting sites within IL-6 (E¹³⁴/S¹³⁵) and IL-11 (G¹¹⁶/S¹¹⁷) and obtained inactive split-Hyper-IL-6 and split-Hyper-IL-11 cytokine precursors. After fusion with split-inteins, PTS resulted in reconstitution of active Hyper-cytokines, which were efficiently secreted from transfected cells. Our strategy comprises the development of a background-free cytokine signaling system from reversibly inactivated precursor cytokines.

The compromise of dynamic disulfide/thiol homeostasis as a biomarker of oxidative stress in trichloroethylene exposure

In this study, we aimed to investigate disulfide/thiol homeostasis in trichloroethylene (TCE) exposure. The study was carried out in 30 nonsmoker TCE-exposed workers with a variety of occupations. Additionally, 30 healthy nonsmoker volunteers were recruited as the control group. TCE exposure was determined by measuring urinary trichloroacetic acid (TCA) concentration. Median urinary TCA levels of exposed workers (20.5 mg/L) were significantly higher than control subjects (5 mg/L). Thiol and disulfide concentrations were determined using a novel automated method. Disulfide/thiol ratio was significantly higher in the exposed group ( p < 0.001). Thiol/disulfide homeostasis was found to be disturbed in TCE-exposed workers. We predict that in TCE-exposed workers this disturbance can be a therapeutic target, and the efficiency of the treatment can easily be monitored by the novel method we used.

Non-canonical interleukin 23 receptor complex assembly: p40 protein recruits interleukin 12 receptor β1 via site II and induces p19/interleukin 23 receptor interaction via site III

IL-23, composed of the cytokine subunit p19 and the soluble α receptor subunit p40, binds to a receptor complex consisting of the IL-23 receptor (IL-23R) and the IL-12 receptor β1 (IL-12Rβ1). Complex formation was hypothesized to follow the "site I-II-III" architectural paradigm, with site I of p19 being required for binding to p40, whereas sites II and III of p19 mediate binding to IL-12Rβ1 and IL-23R, respectively. Here we show that the binding mode of p19 to p40 and of p19 to IL-23R follow the canonical site I and III paradigm but that interaction of IL-23 to IL-12Rβ1 is independent of site II in p19. Instead, binding of IL-23 to the cytokine binding module of IL-12Rβ1 is mediated by domains 1 and 2 of p40 via corresponding site II amino acids of IL-12Rβ1. Moreover, domains 2 and 3 of p40 were sufficient for complex formation with p19 and to induce binding of p19 to IL-23R. The Fc-tagged fusion protein of p40_D2D3/p19 did, however, not act as a competitive IL-23 antagonist but, at higher concentrations, induced proliferation via IL-23R but independent of IL-12Rβ1. On the basis of our experimental validation, we propose a non-canonical topology of the IL-23·IL-23R·IL-12Rβ1 complex. Furthermore, our data help to explain why p40 is an antagonist of IL-23 and IL-12 signaling and show that site II of p19 is dispensable for IL-23 signaling.

Interleukin-6, but not the interleukin-6 receptor plays a role in recovery from dextran sodium sulfate-induced colitis

Interleukin (IL)-6-deficient, but not IL-6 receptor (IL-6R)‑deficient mice present with a delayed skin wound healing phenotype. Since IL-6 solely signals via the IL-6R and glycoprotein 130 (gp130), Il-6r-deficient mice are expected to exhibit a similar phenotype as Il-6-deficient mice. However, p28 (IL-30) and ciliary neurotrophic factor (CNTF) have been identified as additional low‑affinity ligands of the IL-6R/gp130/LIFR complex. IL-6 plays an inflammatory and regenerative role in inflammatory bowel disease (IBD). In the present study, we compared Il-6r-deficient mice with mice treated with neutralizing IL-6 monoclonal antibody (mAb) in a model of dextran sodium sulfate (DSS)-induced colitis. Our results, in agreement with those of previous reports, demonstrated that IL-6 mAbs slightly attenuated DSS-induced colitis during the regeneration phase. Il-6r-deficient mice and mice with tissue-specific deletion of the Il-6r in the myeloid cell lineage (LysMCre) with acute and chronic DSS-induced colitis were, however, indistinguishable from wild-type mice. Our data suggest that IL-6 and IL-6R have an additional role in colitis, apart from the IL-6/IL-6R classic and trans-signaling.

Minimal interleukin 6 (IL-6) receptor stalk composition for IL-6 receptor shedding and IL-6 classic signaling

Signaling of the pleiotropic cytokine Interleukin-6 (IL-6) is coordinated by membrane-bound and soluble forms of the IL-6 receptor (IL-6R) in processes called classic and trans-signaling, respectively. The soluble IL-6R is mainly generated by ADAM10- and ADAM17-mediated ectodomain shedding. Little is known about the role of the 52-amino acid-residue-long IL-6R stalk region in shedding and signal transduction. Therefore, we generated and analyzed IL-6R stalk region deletion variants for cleavability and biological activity. Deletion of 10 amino acids of the stalk region surrounding the ADAM17 cleavage site substantially blocked IL-6R proteolysis by ADAM17 but only slightly affected proteolysis by ADAM10. Interestingly, additional deletion of the remaining five juxtamembrane-located amino acids also abrogated ADAM10-mediated IL-6R shedding. Larger deletions within the stalk region, that do not necessarily include the ADAM17 cleavage site, also reduced ADAM10 and ADAM17-mediated IL-6R shedding, questioning the importance of cleavage site recognition. Furthermore, we show that a 22-amino acid-long stalk region is minimally required for IL-6 classic signaling. The gp130 cytokine binding sites are separated from the plasma membrane by ~96 Å. 22 amino acid residues, however, span maximally 83.6 Å (3.8 Å/amino acid), indicating that the three juxtamembrane fibronectin domains of gp130 are not necessarily elongated but somehow flexed to allow IL-6 classic signaling. Our findings underline a dual role of the IL-6R stalk region in IL-6 signaling. In IL-6 trans-signaling, it regulates proper proteolysis by ADAM10 and ADAM17. In IL-6 classic-signaling, it acts as a spacer to ensure IL-6·IL-6R·gp130 signal complex formation.

Selective imidazolidine ring opening during complex formation of iron(III), copper(II), and zinc(II) with a multidentate ligand obtained from 2-pyridinecarboxaldehyde N-oxide and triethylenetetramine

The condensation of 2-pyridinecarboxaldehyde N-oxide and triethylenetetramine yields a product with two imidazolidine rings, as proven by a solid-state X-ray structure analysis as well as by NMR solution spectra. This ligand, L1, undergoes a ring-opening reaction on complex formation with Cu(II), yielding [CuL2]2+ where L2 functions as a pentadentate ligand, containing only one imidazolidine ring. On complexation with Zn(II) and Fe(III), both rings are opened and the complexes [ZnL3]2+ and [FeL3]3+ with a hexadentate L3 ligand are formed. The recrystallization of [ZnL3]2+ from DMSO solution results in the complex [ZnL1(DMSO)2]2+ in which L1 behaves as a tetradentate ligand. Thus L1, L2, and L3 are structural isomers with two, one, or no imidazolidine rings, as confirmed by X-ray structure analyses. The intramolecular ring formation is the result of the nucleophilic addition of the N(amino) group to the electrophilic sp2-hybridized -HC delta+=N site. Owing to the absence of the chelate effect on the sp3-hybridized carbon atom belonging to the imidazolidine ring, the ring opening is facilitated and readily observed upon complex formation with Cu(II), Zn(II), and Fe(III).

[Adverse effects of the work process in relation to pregnancy]

Some characteristics of the working activity of pregnant women were investigated during statistical analysis of data pertaining to 6166 naturally terminated pregnancies in the Gottwaldov district (1981-1983). The threatening element from the aspect of spontaneous abortions in the first trimester is work done during most of the shift in a standing position without movement. There also the highest incidence of small-for-age and hypotrophic foetuses was found. Work involving constant movement is a risk and may lead to premature delivery. Manipulation with loads threatens pregnancy by reproductive losses (in particular a higher incidence of haemorrhage during the first trimester) and by prematurity. Social tension at the place of work also threatens pregnancy - at conflict in work places a significantly increased risk was proved. It was also proved that it is important to respect medical recommendation to transfer pregnant women to other work. As to associated factors, commuting was investigated and its adverse effect is particularly apparent when the distance is more than 25 km.

[The occupation of the pregnant woman in relation to the course and outcome of pregnancy]

Some occupations are associated with an extra risk during pregnancy. Intensive action is not involved (the relative risk does not exceed the value of 2,000) but with regard to the number of women in these categories it is a significant extensive factor. Based on the results of an analysis of a group of all naturally terminated pregnancies in the district of Gottwaldov in 1981-1983 (6166 pregnancies), as compared with the mean an increased ratio of reproductive losses was recorded in charwomen, hairdressers, teachers, engineers with university education. Prematurity was recorded in particular in waitresses, shop-assistants, nurses, other health workers and women doctors. Workers on the whole have relatively favourable results, however, the risk in these occupation more frequently develops into actual failure of pregnancy (haemorrhage in the 1st trimester, imminent premature child birth). These workers are also more protected by legal leave after a previous childbirth, as compared with other occupations.

The Convergence of Computing and Telecommunications Systems

Since we do not know of any completely workable solutions to the problems we have considered, we shall settle for a few general observations: 1) The public availability of socially useful computer communications services is and has been held back by legal battles that are now under way between the potential suppliers. 2) No simple resolution of these issues in the near future seems likely in view of the past conceptual separation of computers and communications doctrines. 3) The current policy is to determine whether the nation shall or shall not have certain computer communications services, by the adversary process. In this process, often only the voices of the loudest adversary suppliers are heard. 4) Although there can be no certainty that better alternatives cannot be devised, we believe that such a possibility assumes a higher probability if the key actors come from the technical community sectors more representative of the future consumers. 5) If we are to have the new services that are possible, we need an approach that makes better use of the technologists' dreams and goals rather than have future prospects excessively bound by lawyers paid to preserve the interests of their clients, irrespective of any secondary consequences. 6) We cannot be sanguine about this possibility, as technological statesmanship is too easily corrupted by the same forces that have placed us in this predicament. Furthermore, even if not corrupted, beneficial cooperation can too readily be regarded as simply collusion. 7) Although we do not have any clear answer, we do know that present approaches are not taking us where we want to go very rapidly and that alternative approaches should at least be considered.