Transgenic expression of a CD83-immunoglobulin fusion protein impairs the development of immune-competent CD4-positive T cells

The murine transmembrane glycoprotein CD83 is an important regulator for both thymic T cell maturation and peripheral T cell response. CD83 deficiency leads to a block in the thymic maturation of CD4-positive T cells, and interference with peripheral CD83/CD83 ligand interaction by addition of soluble CD83 suppresses immune responses in vivo and in vitro. Here we report the generation of a mouse transgenic for a fusion protein consisting of the extracellular domain of murine CD83 fused to the constant part of human IgG1 heavy chain. Thymic selection of CD4-positive T cells was unchanged in CD83Ig transgenic and in CD83Ig/OT-2 double-transgenic mice. However, thymic and peripheral CD4-positive T cells derived from CD83Ig/OT-2 transgenic mice displayed a reduced cytokine response to antigenic stimulation in vitro, whereas CD83Ig/OT-1-derived CD8-positive T cells showed normal cytokine secretion. The T cell defect was relevant in vivo, since a sub-lethal infection with Trypanosoma cruzi led to an increased parasitemia and reduced survival rate of CD83Ig transgenic mice compared to wild-type C57BL/6 mice. In contrast, in vivo application of recombinant CD83Ig did not result in an increase in parasitemia. Taken together our data suggest that thymic selection in the presence of CD83Ig leads to an intrinsic T cell defect of CD4-positive T cells resembling the phenotype described for CD4-positive T cells derived from CD83-deficient mouse strains.     

Gesundheitsförderung für Pflegeheimbewohner?

Background

Institutions of long-term care provide a special setting for health promotion in old age, which has been payed little attention to so far. Although various studies have proved the effects of health promotion even in old age and its contribution to quality of life, there is a lack of health promoting strategies for elderly people who are in need of care, especially for those who live in a nursing home.

Methods

In this study the concepts of health and the special health-related needs among nursing home residents were analyzed in order to identify the spectrum of possible health promoting interventions for this target group. Data was collected in 15 qualitative interviews (12 women and 3 men) with biographical and narrative elements. Data was analyzed on the basis of Faltermaier (Gesundheitsbewusstsein und Gesundheitshandeln – Über den Umgang mit Gesundheit im Alltag. Beltz, Weinheim, 1994) and Glaser und Strauss (The discovery of grounded theory: strategies for qualitative research. Aldine, New York, 1967).

Results

Data analysis showed a very extensive comprehension of health among the participants, which included mental, social and ethical dimensions. On the basis of these concepts, concrete interventions could be developed to improve health and well-being in nursing homes. Most of these interventions are settled on psychosocial and ethical level, because these aspects was attached great importance related to their experience of health in the current life situation. In detail, the following health promoting measures can be recommended: support of autonomy and one’s own initiative, offers to leave the room and the facility, promotion of social contacts within and beyond the institution, promotion of self-determination by scopes for decision-making, consideration of individual habits and wishes, offers to varied activities, offer and allocation of assignments and responsibilities, assurance of security and reliability, support of individual health-related beliefs and behavior as well as promotion and making aware of resources.

Conclusions

The results of the study can serve as a science-based groundwork for a health-oriented long-term care. To pursue this way purposefully and sustainably, there are various needs for action, especially regarding the organizational structures in nursing homes and the qualification of the personnel. In order to implement the recommended procedures successfully, nurses primarily need social and communicative skills and a special caring attitude which is characterized by empathy, empowerment and participation. In addition, further research is required, concerning the possibilities of health promotion for nursing home residents with dementia.     

Erlotinib resistance in EGFR-amplified glioblastoma cells is associated with upregulation of EGFRvIII and PI3Kp110δ

Background

The treatment efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors like erlotinib has not met expectations for glioblastoma therapy, even for EGFR-overexpressing tumors. We determined possible mechanisms of therapy resistance using the unique BS153 glioblastoma cell line, which has retained amplification of the egfr gene and expression of EGFR variant (v)III.

Methods

Functional effects of erlotinib, gefitinib, and cetuximab on BS153 proliferation, migration, and EGFR-dependent signal transduction were systematically compared in vitro. The tumor-initiating capacity of parental and treatment-resistant BS153 was studied in Naval Medical Research Institute/Foxn1^nu mice. Potential mediators of resistance were knocked down using small interfering (si)RNA.

Results

Erlotinib and gefitinib inhibited proliferation and migration of BS153 in a dose-dependent manner, whereas cetuximab had no effect. BS153 developed resistance to erlotinib (BS153^resE) but not to gefitinib. Resistance was associated with strong upregulation of EGFRvIII and subsequent activation of the phosphatidylinositol-3-OH kinase (PI3K) pathway in BS153^resE and an increased expression of the regulatory 110-kDa delta subunit of PI3K (p110δ). Knockdown of EGFRvIII in BS153^resE largely restored sensitivity to erlotinib. Targeting PI3K pharmacologically caused a significant decrease in cell viability, and specifically targeting p110δ by siRNA partially restored erlotinib sensitivity in BS153^resE. In vivo, BS153 formed highly invasive tumors with an unusual growth pattern, displaying numerous satellites distant from the initial injection site. Erlotinib resistance led to delayed onset of tumor growth as well as prolonged overall survival of mice without changing tumor morphology.

Conclusions

EGFRvIII can mediate resistance to erlotinib in EGFR-amplified glioblastoma via an increase in PI3Kp110δ. Interfering with PI3Kp110δ can restore sensitivity toward the tyrosine kinase inhibitor.     

Adaptive Designs for Two Candidate Primary Time-to-Event Endpoints

In clinical trials, the choice of an adequate primary endpoint is often difficult. Besides its clinical relevance, the endpoint must be measurable within reasonable time and must allow differentiating between the treatments. Often, the most relevant endpoint is ‘’time-to-death,” but if the overall survival prognosis is good, only a few deaths are observed during the study duration. A possible solution is to use surrogate endpoints instead. However, various examples from the literature demonstrate that surrogates do not always perform as intended. Sometimes, the surrogate effect is smaller than for the original endpoint, or the latter shows a higher effect than anticipated so using the surrogate is not reasonable. In this work, different adaptive design strategies for two candidate endpoints are proposed to solve these problems. The idea is to base the efficacy proof on the significance of at least one endpoint. At an interim analysis, both candidates are evaluated. If it is not possible to stop the study early, the sample size is recalculated based on the more promising endpoint. The new methods are illustrated by a clinical study example and compared in terms of power and sample size using Monte Carlo simulations. The software code is provided as supplementary material.     

Corneal confocal microscopy reveals small nerve fibre loss correlating with motor function in adult spinal muscular atrophy

Background

5q Spinal muscular atrophy (SMA) is a progressive, inherited, and severely disabling – yet treatable – motor neuron disease. Although treatment options have evolved in recent years, biomarkers for treatment monitoring and prognosis prediction remain elusive. Here, we investigated the utility of corneal confocal microscopy (CCM), a non-invasive imaging technique to quantify small corneal nerve fibres in vivo, as a diagnostic tool in adult SMA.

Methods

In this cross-sectional study, 19 patients with SMA type 3 and 19 healthy controls underwent CCM to measure corneal nerve fibre density (CNFD), corneal nerve fibre length (CNFL), and corneal nerve branch density (CNBD), as well as corneal immune cell infiltration. Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM) scores and a 6-Minute Walk Test (6MWT) were conducted to explore any correlation between CCM findings and motor function.

Results

Corneal nerve fibre parameters were decreased in SMA patients versus healthy controls (CNFD: p = 0.030; CNFL: p = 0.013; CNBD: p = 0.020) in the absence of relevant immune cell infiltration. CNFD and CNFL correlated with HFMSE scores (CNFD: r = 0.492, p = 0.038; CNFL: r = 0.484, p = 0.042) and distance covered in the 6MWT (CNFD: r = 0.502, p = 0.042; CNFL: r = 0.553, p = 0.023).

Conclusions

Corneal confocal microscopy CCM reveals sensory neurodegeneration in SMA, thereby supporting a multisystem view of the disorder. Subclinical small nerve fibre damage correlated with motor function. Thus, CCM may be ideally suited for treatment monitoring and prognosis.     

Fourteen new microsatellite markers for the Visayan tarictic hornbill (Penelopides panini) and their cross-species applicability among other endangered Philippine hornbills

Fourteen microsatellite markers were isolated and characterized for the endangered Visayan tarictic hornbill (Penelopides panini, Aves: Bucerotidae). In an analysis of 76 individuals, the number of alleles per locus varied from one to 12. Expected and observed heterozygosity ranged from 0.00 to 0.87 and from 0.00 to 0.89, respectively. All primers also amplify microsatellite loci in Luzon tarictic hornbill (Penelopides manillae), Mindanao tarictic hornbill (Penelopides affinis), the critically endangered Walden??s hornbill (Aceros waldeni) and the near-threatened writhed hornbill (Aceros leucocephalus). Two loci which are monomorphic in P. panini were found polymorphic in at least one of the other species. These 14 new microsatellite markers specifically developed for two genera of Philippine hornbills, in combination with those already available for the hornbill genera Buceros and Bucorvus, comprise a reasonable number of loci to genetically analyse wild and captive populations of these and probably other related, often endangered hornbills.     

Experimental Studies on Facial Nerve Regeneration

Insufficient recovery after injury of a peripheral motor nerve is due to (1) inappropriate pathfinding as a result of axonal regrowth to inappropriate targets, (2) excessive collateral axonal branching at the lesion site, and (3) polyinnervation of the neuromuscular junctions (NMJs). The rat facial nerve model is often used because of its simple and reliable readout to measure recovery of function (vibrissal whisking). Over the last decades scientists have concentrated their efforts to combat mostly NMJ polyinnervation, because it turned out to be very difficult to reduce collateral axonal branching and impossible to navigate thousands of axons toward the original fascicles. In the past, several groups of scientists concentrated their efforts to reduce the activity-dependent polyinnervation of NMJs by electrical stimulation of the muscles (square 0.1 msec pulses at 5 Hz). The results showed no recovery of functions and a severe reduction in the number of innervated NMJs to approximately one fifth of those observed in intact animals. More recent experiments, however, have shown that motor recovery improved significantly following mechanical stimulation of the denervated facial muscles (vibrissal and orbicularis oculi) and that restored functions could invariably be linked to reduced polyinnervation at the NMJ while the number of innervated NMJ remained the same. These results suggest that clinically feasible and effective therapies could be developed and tested in the near future. Anat Rec, 302:1287–1303, 2019. © 2019 Wiley Periodicals, Inc.     

Ischemic stroke and dose adjustment of oral Factor Xa inhibitors in patients with atrial fibrillation

Journal of Neurology - Oral Factor Xa inhibitors for the prevention of stroke in atrial fibrillation require dose adjustment based on certain clinical criteria, but the off-label use of the reduced...