Dying autologous cells as instructors of the immune system

In an organism, cell death occurs at many different sites and in many different forms. It is frequently part of normal development or serves to maintain cell homeostasis. In other cases, cell death not only occurs due to injury, disease or infection, but also as a consequence of various therapeutic interventions. However, in all of these scenarios, the immune system has to react to the dying and dead cells and decide whether to mount an immune response, to remain quiet or to initiate healing and repopulation. This is essential for the organism, testified by many diseases that are associated with malfunctioning in the cell death process, the corpse removal, or the ensuing immune responsiveness. Therefore, dying cells generally have to be considered as instructors of the immune system. How this happens and which signals and pathways contribute to modulate or shape the immune response is still elusive in many conditions. The articles presented in this Special Issue address such open questions. They highlight that the context in which cell death occurs will not only influence the cell death process itself, but also affect the surrounding cellular milieu, how the generation and presence of 'eat me' signals can have an impact on cell clearance, and that the exact nature of the residual 'debris' and how it is processed are fundamental to determining the immunological consequences. Hopefully, these articles initiate new approaches and new experiments to complete our understanding of how cell death and the immune system interact with each other.

Altered glycosylation of complexed native IgG molecules is associated with disease activity of systemic lupus erythematosus

In addition to the redundancy of the receptors for the Fc portion of immunoglobulins, glycans result in potential ligands for a plethora of lectin receptors found in immune effector cells. Here we analysed the exposure of glycans containing fucosyl residues and the fucosylated tri-mannose N-type core by complexed native IgG in longitudinal serum samples of well-characterized patients with systemic lupus erythematosus. Consecutive serum samples of a cohort of 15 patients with systemic lupus erythematosus during periods of increased disease activity and remission were analysed. All patients fulfilled the 1982 American College of Rheumatology classification criteria. Sera of 15 sex- and age-matched normal healthy blood donors served as controls. The levels and type of glycosylation of complexed random IgG was measured with lectin enzyme-immunosorbent assays. After specifically gathering IgG complexes from sera, biotinylated lectins Aleuria aurantia lectin and Lens culinaris agglutinin were employed to detect IgG-associated fucosyl residues and the fucosylated tri-mannose N-glycan core, respectively. In sandwich-ELISAs, IgG-associated IgM, IgA, C1q, C3c and C-reactive protein (CRP) were detected as candidates for IgG immune complex constituents. We studied associations of the glycan of complexed IgG and disease activity according to the physician's global assessment of disease activity and the systemic lupus erythematosus disease activity index 2000 documented at the moment of blood taking. Our results showed significantly higher levels of Aleuria aurantia lectin and Lens culinaris agglutinin binding sites exposed on IgG complexes of patients with systemic lupus erythematosus than on those of normal healthy blood donors. Disease activity in systemic lupus erythematosus correlated with higher exposure of Aleuria aurantia lectin-reactive fucosyl residues by immobilized IgG complexes. Top levels of Aleuria aurantia lectin-reactivity were found in samples taken during the highest activity of systemic lupus erythematosus. Our results show that native circulating IgG complexes from active systemic lupus erythematosus patients expose fucosyl residues and their glycan core is accessible to soluble lectins. Two putative mechanisms may contribute to the increased exposure of these glycans: (1) the canonical N-glycosylation site of the IgG-CH2 domain; (2) an IgG binding non-IgG molecule, like complement or C-reactive protein. In both cases the complexed IgG may be alternatively targeted to lectin receptors of effector cells, e.g. dendritic cells.

Ein Beitrag zur photoinduzierten Desaminierung substituierter 1.2.4-Triazinone / A Contribution to the Photoinduced Desamination of 1,2,4-Triazinones

Solution-phase photoreactions of 4-amino-substituted 1,2,4-triazin-5(4H)-ones (1a-j) in different solvents using UV light with wavelengths greater than 290 nm have been investigated. The results show, that the desamination reaction is influenced by both oxygen and water. The photoexperiments showed clearly that OOH-radicals take part in the first step of reaction.

The Role of Reactive Oxygen Species in the Light-Induced Deformation of DNA

Dimerizations and reactions with water of pyrimidine bases are the primary steps held respon­sible for the deformation of DNA at short wavelengths in vitro and in vivo experiments. However the influence of oxygen in combination with water on the UV deformation at wavelengths rep­resentative for troposphere is evident from the observed data and both together are needed to change the DNA structure. The only plausible explanation for the effect of oxygen is the forma­tion of reactive oxygen species during the UV irradiation of DNA. In the present work the deformation of DNA by different oxygen species like singlet oxygen (1O2), superoxideanion (O2 -), hydroxyradical (·OH), ozone (O3) and hydrogenperoxide (H2O2) is excluded with the help of chemical-trapping experiments. The photo-induced transformation proceeds via excited states of DNA. which react with groundstate oxygen to afford peroxide.

Preferential host switching and codivergence shaped radiation of bark beetle symbionts, nematodes of Micoletzkya (Nematoda: Diplogastridae)

Host-symbiont systems are of particular interest to evolutionary biology because they allow testable inferences of diversification processes while also providing both a historical basis and an ecological context for studies of adaptation. Our investigations of bark beetle symbionts, predatory nematodes of the genus Micoletzkya, have revealed remarkable diversity of the group along with a high level of host specificity. Cophylogenetic analyses suggest that evolution of the nematodes was largely influenced by the evolutionary history of beetles. The diversification of the symbionts, however, could not be attributed to parallel divergence alone; our results indicate that adaptive radiation of the nematodes was shaped by preferential host shifts among closely related beetles along with codivergence. Whereas ecological and geographic isolation have played a major role in the diversification of Micoletzkya at shallow phylogenetic depths, adaptations towards related hosts have played a role in shaping cophylogenetic structure at a larger evolutionary scale.

Detection of nosocomial Clostridium difficile infections with toxigenic strains despite negative toxin A and B testing on stool samples

A two-step diagnostic algorithm is recommended to detect Clostridium difficile infections; however, samples are regularly found that are glutamate dehydrogenase (GDH) positive but stool toxin negative. In the present single-centre prospective study we focused on these 'difficult-to-interpret' samples and characterized them by anaerobic culture, toxigenic culture, slpA sequence typing and multiplex PCR (GenoType CDiff). The majority of stool toxin A and B-negative samples have been caused by toxigenic strains including ribotype 027. The multiplex PCR was faster and more sensitive compared with culture and allowed preliminary identification of hypervirulent strains in stool samples on the same day.

Addendum to "Two-fluid confined flow in a cylinder driven by a rotating endwall"

In a recent paper [Phys. Rev. E 85, 016308 (2012)], we reported on numerical simulations of swirling two-phase flows in which for cases where the viscosity of the upper fluid is sufficiently smaller than that of the lower fluid, a small region of reversed flow is present on the interface. In this Brief Report, we show that the reported reversed flow is grid converged and comment further on its physical origin.

Structural and Magnetic Properties of e-Beam Prepared CoxPt1-x Alloy Films

We have investigated structural and magnetic properties of CoPt alloy films with strong perpendicular magnetic anisotropy in the thickness range between 100Å and 400A. From a detailed x-ray analysis we find highly (111) -textured CoPt Microcrystal-lites in all samples. STM studies reveal a granular topography with grain diameters of up to 250Å. Measurements of hysteresis loops yield a saturation field which increases with thickness, and which is consistent with a freely mobile domain Model. Brillouin light scattering measurements of the frequencies of the surface and standing spin wave modes yield a bulk exchange constant, which is strongly dependent on the Pt content.

Autoantibodies against galectin-2 peptides as biomarkers for the antiphospholipid syndrome

Autoantibodies against opsonins of dying and dead cells mediate Fcγ receptor-dependent phagocytosis of autologous apoptotic and necrotic cells and hereby tend to elicit inflammation instead of silent clearance. We analysed sera of patients with chronic autoimmune diseases for the occurrence of IgG autoantibodies recognizing galectins. These pluripotent effectors can also bind to apoptotic or necrotic cells. Patients with antiphospholipid syndrome (APS; n = 104) and systemic lupus erythematosus (SLE; n = 62) were examined, healthy donors ( n = 31) served as controls. Selected peptides of galectin (Gal)-2 were employed for peptide-based ELISAs. Levels of anti-Gal-2PEP-IgG were significantly increased in SLE and APS when compared with controls. In addition, patients with APS showed significantly higher levels of anti-Gal-2PEP-IgG compared with patients with SLE. Anti-Gal-2PEP-IgG may, therefore, be considered novel biomarkers for APS.

Does increased sunlight exposure work as a strategy to improve vitamin D status in the elderly: a cluster randomised controlled trial

SUMMARY

Sunlight exposure by improving vitamin D status could be a simple public health strategy in reducing falls among frail elder people. In a randomised controlled trial, adherence to sunlight exposure was low (median adherence, 26%) and no effect of increased UV exposure on falls risk was observed (incidence rate ratio (IRR) 1.06, P = 0.73).

INTRODUCTION

This study aimed to determine whether increased sunlight exposure was effective to improve vitamin D status and reduce falls in the elderly.

METHODS

In a cluster randomised controlled trial (NCT00322166 at ClinicalTrials.gov), 602 residents aged 70 or more (mean age, 86.4 years; 71% female) were recruited from 51 aged care facilities in Northern Sydney, Australia. Participants were randomised by facility to receive either increased sunlight exposure (additional 30-40 min/day in the early morning) with (UV+) or without (UV) calcium supplementation (600 mg/day) or neither (control) for a year. The co-primary endpoints were change in serum 25 hydroxy vitamin D (25OHD) and falls incidence after 12 months.

RESULTS

Adherence to sunlight exposure was low (median adherence, 26%; IQR, 7%-45%). Serum 25OHD levels were low at baseline (median, 32.9 nmol/L) and increased only slightly depending on the number of sunlight sessions attended over 12 months (P = 0.04). During the study, 327 falls occurred in 111 (54%) subjects in the control group, 326 falls in 111 (58%) subjects in the UV only group and 335 falls in 108 (52%) subjects in the UV+ group. By intention-to-treat analysis, there was no significant effect of increased UV exposure on falls risk (IRR, 1.06; 95% CI, 0.76-1.48; P = 0.73). However, in 66 participants who attended ≥130 sessions per year (adherence, ≥50% of 260 sessions-five per week), falls were significantly reduced (IRR, 0.52; 95% CI, 0.31-0.88; P = 0.01) compared with the control group.

CONCLUSIONS

Increased sunlight exposure did not reduce vitamin D deficiency or falls risk in frail older people. This public health strategy was not effective most likely due to poor adherence to the intervention.

Two-fluid confined flow in a cylinder driven by a rotating end wall

The flow of two immiscible fluids completely filling an enclosed cylinder and driven by the rotation of the bottom end wall is studied numerically. The simulations are in parameter regimes where there is significant advection of angular momentum, i.e., the disk rotation rate is fast compared to the viscous diffusion time. We consider two classes of scenarios. The first consists of cases that are straightforward to reproduce in physical experiments where only the rotation rate and the viscosity ratio of the fluids are varied. Then we isolate different forces acting on the system such as inertia, surface tension, and gravity by studying variations in individual governing parameters. The viscosity ratio determines how quickly the upper fluid equilibriates dynamically to the flow in the lower fluid and plays a major role in determining how vortex lines are bent in the neighborhood of the interface between the two fluids. This in turn determines the structure of the interfacial layer between the two swirling fluids, which is responsible for the flow in the upper fluid. The simulations show that even when there is significant interfacial deformation, both the dynamics and the equilibrium flow are dominated by vortex bending rather than vortex stretching. The simulations show that for the range of immiscible fluids considered, surface tension effects are significant. Increased surface tension reduces the degree to which the interface is deformed and the limit of zero surface tension is not an appropriate approximation.

Torsional bridge setup for the characterization of integrated circuits and microsensors under mechanical shear stress

We present a torsional bridge setup for the electro-mechanical characterization of devices integrated in the surface of silicon beams under mechanical in-plane shear stress. It is based on the application of a torsional moment to the longitudinal axis of the silicon beams, which results in a homogeneous in-plane shear stress in the beam surface. The safely applicable shear stresses span the range of ±50 MPa. Thanks to a specially designed clamping mechanism, the unintended normal stress typically stays below 2.5% of the applied shear stress. An analytical model is presented to compute the induced shear stress. Numerical computations verify the analytical results and show that the homogeneity of the shear stress is very high on the beam surface in the region of interest. Measurements with piezoresistive microsensors fabricated using a complementary metal-oxide-semiconductor process show an excellent agreement with both the computational results and comparative measurements performed on a four-point bending bridge. The electrical connection to the silicon beam is performed with standard bond wires. This ensures that minimal forces are applied to the beam by the electrical interconnection to the external instrumentation and that devices with arbitrary bond pad layout can be inserted into the setup.

[Multi-dose packaging of drugs as the causative vehicle for multidrug-resistant Enterobacter cloacae: new results from a case-control study]

Hospital hygiene faces cross-cutting and methodological challenges that are time consuming and require specialised knowledge. In outbreak situations German federal states can request assistance from infectious disease epidemiologists at the Robert Koch Institute (RKI). The presented study describes the successful collaboration of local hygienists, microbiologists, clinicians, health authorities and the epidemiologists of the RKI in the investigation of an outbreak of multidrug-resistant Enterobacter (E.) cloacae in 2009 in a children's hospital. The outbreak was discovered in July 2009 when E. cloacae was detected in 12 patients in the neonatal and paediatric intensive care unit (NICU). Hygiene measures were intensified for infection control, and the RKI was invited by the responsible regional health authorities in October 2009 to assist in the outbreak investigation. We conducted a retrospective matched case-control study to identify risk factors for E. cloacae colonisation and infection. We identified a case as any child in the NICU from 1st May to 5th October 2009 with laboratory confirmation of the outbreak clone. Controls were patients staying in the NICU (> 72 h before the case's diagnosis) and swab-negative for the outbreak clone. We used standardised questionnaires to collect demographic and medical information. Matched odds ratios (mOR) were calculated by bivariate and multivariable conditional logistic regression. Environmental investigations were conducted. We identified 28 colonised and 3 bacteraemic cases. 29 matched case-control pairs were included in the study. Multivariable analysis revealed an association between E. cloacae diagnosis and the receipt of oral drugs at the bed-side from multidose packaging (mOR=1.8/drug; p=0.006). No specific drug was identified; microbiological investigation of drugs was negative. This multiresistant E. cloacae outbreak was most likely distributed by oral application using contaminated multidose drug packaging extrinsically contaminated via hands of personnel. No further cases occurred for 6 weeks after protocols for handling oral drugs were changed (smaller packaging, patient-based storage, and limited circulation time). Special attention and thorough hygiene protocols are needed for the distribution of oral medication. In NICUs the use of multi-dose medications should be avoided. The cooperation between locally available expertise and infectious disease epidemiologists enabled the discovery of a previously unidentified risk factor.

Significant decreases of circulating endothelial cells but no changes of endothelial progenitor cells or mesenchymal stem cells during antidepressant treatment

Objective

We examined leukocyte numbers, circulating endothelial progenitor cells (CD34+, CD133+), circulating mesenychmal stem cells (CD105+) and circulating endothelial cells (CD146+) at the beginning, after 4 weeks and at the end of an inpatient antidepressant treatment.

Methods

24 insufficiently pretreated inpatients with major depression were included. At admission, after four weeks and at demission blood samples were obtained, and cell numbers were counted by flow cytometric analysis (FACS). At each examination the severity of the depression was evaluated with the Beck Depression Inventory (BDI). We were especially interested in the changes of cell numbers during the antidepressant treatment. The data were statistically analyzed using SPSS 14.0.

Results

The mean BDI score fell from 34 ± 7 at the beginning to 26.5 ± 6.6 after four weeks and 13.5 ± 5.7 at demission. The longer the overall duration of the depressive illness, the higher the number of leukocytes at admission (P < 0.0001). The lower the depression score at demission, the lower the final number of leukocytes (P < 0.001). During the antidepressant treatment the BDI depression score improved significantly (P < 0.0001). The number of CD146+ cells showed a significant decrease (P < 0.006). We did not find any significant changes of circulating CD34+, CD105+, or CD133+ cells during the antidepressant treatment.

Conclusions

The leukocyte results suggest an activation of the immune system in major depression and a deactivation due to antidepressant treatment.

High hydrostatic pressure treatment generates inactivated mammalian tumor cells with immunogeneic features

Most of the classical therapies for solid tumors have limitations in achieving long-lasting anti-tumor responses. Therefore, treatment of cancer requires additional and multimodal therapeutic strategies. One option is based on the vaccination of cancer patients with autologous inactivated intact tumor cells. The master requirements of cell-based therapeutic tumor vaccines are the: (a) complete inactivation of the tumor cells; (b) preservation of their immunogenicity; and (c) need to remain in accordance with statutory provisions. Physical treatments like freeze-thawing and chemotherapeutics are currently used to inactivate tumor cells for vaccination purposes, but these techniques have methodological, therapeutic, or legal restrictions. For this reason, we have proposed the use of a high hydrostatic pressure (HHP) treatment (p >or= 100 MPa) as an alternative method for the inactivation of tumor cells. HHP is a technique that has been known for more than 100 years to successfully inactivate micro-organisms and to alter biomolecules. In the studies here, we show that the treatment of MCF7, B16-F10, and CT26 tumor cells with HHP >or= 300 MPa results in mainly necrotic tumor cell death forms displaying degraded DNA. Only CT26 cells yielded a notable amount of apoptotic cells after the application of HHP. All tumor cells treated with >or= 200 MPa lost their ability to form colonies in vitro. Furthermore, the pressure-inactivated cells retained their immunogenicity, as tested in a xenogeneic as well as syngeneic mouse models. We conclude that the complete tumor cell inactivation, the degradation of the cell's nuclei, and the retention of the immunogeneic potential of these dead tumor cells induced by HHP favor the use of this technique as a powerful and low-cost technique for the inactivation of tumor cells to be used as a vaccine.