The adhesion receptor CD155 determines the magnitude of humoral immune responses against orally ingested antigens

CD155, originally known as the cellular receptor for poliovirus, is the founding member of a subfamily of immunoglobulin-like adhesion receptors. Apart from its function in establishing adherens junctions between contacting epithelial cells, the engagement of CD155 with two recently identified ligands, CD226 and CD96, mediates immunologically relevant processes such as NK cell-driven killing of tumor cells in humans. Here we report on the generation and immunological analysis of mice constitutively deficient of CD155. Moreover, the expression profile of CD155 on hematopoietic cells has been determined using newly established antibodies. CD155-deficient mice develop normally without displaying an overt phenotype. However, the animals are distinguished by distinct deficits in the development of a regular humoral immune response. Whereas systemic challenges revealed no differences, orally administered antigen evoked less efficient IgG and IgA antibody responses despite of normal IgM titers when compared to wild-type mice. Therefore, CD155 may assist in an efficient humoral immune response generated within the intestinal immune system.     

IL-10-producing monocytes differentiate to alternatively activated macrophages and are increased in atopic patients

BACKGROUND: Recently the immune regulatory role of T cell-derived IL-10 in allergic disease has been extensively studied. In contrast, there is mounting evidence that IL-10 might also have a role in the perpetuation of allergic inflammation and fibrotic remodeling. It has been reported that alternatively (IL-4) activated macrophages (aaMPhi) produce large quantities of IL-10 and lack IL-12 production. OBJECTIVE: Bearing this in mind, we hypothesized whether functionally different properties of IL-10-producing monocytes could be identified. METHODS: Intracellular cytokine expression of IL-10, IL-12, and IL-6 in peripheral blood CD14(+) monocytes was measured in 19 atopic patients and 18 healthy control subjects by means of flow cytometry. In addition, IL-10-secreting monocytes were sorted by means of flow cytometry. Capabilities of these cells regarding further differentiation, accessory cell capacity, and surface molecule expression were analyzed. RESULTS: Our data show a dichotomous expression pattern of either IL-10 or IL-12p40/p70 in peripheral blood monocytes after LPS stimulation. Compared with healthy control subjects, the percentage of IL-10-producing monocytes was significantly increased in atopic patients. IL-10-secreting monocytes were isolated by using an IL-10 secretion assay, and functional analysis of these sorted cells revealed that IL-10-secreting monocytes preferentially differentiate into suppressor of cytokine signaling 3 expressing aaMPhi, which perpetuate T(H)2 immune response. CONCLUSION: Our study shows the existence of an IL-10-producing monocyte subset, which is increased in atopic disease and which might facilitate allergic inflammation and fibrotic remodeling by differentiation into aaMPhi. CLINICAL IMPLICATIONS: Controlling aaMPhi in T(H)2-driven inflammatory processes might be a novel target for intervention strategies.     

Sequence Analysis of TNFRSF13b, Encoding TACI, in Patients with Systemic Lupus Erythematosus

B cell activating factor belonging to the TNF family (BAFF) and a proliferation inducing ligand (APRIL), and their receptors BAFF receptor (BAFFR), B cell maturation antigen (BCMA), and transmembrane activator and CAML interactor (TACI) are involved in the regulation of B cell homeostasis and differentiation. BAFF overexpression leads to systemic lupus erythematosus (SLE) in mice and elevated BAFF levels have been observed in human SLE and mouse models for SLE. Furthermore, genetic inactivation of TACI in mice results in a SLE-like phenotype. Based on our recent finding that TACI is mutated in patients with common variable immunodeficiency, of whom more than 30% suffer from autoimmune conditions, we analyzed TACI in humans with SLE. Sequence analysis of TNFRSF13b/TACI in 119 unrelated SLE patients revealed four variants: R20C in exon 1, R72H in exon 3, the silent variation c.327 G > A in exon 3, and A181E in exon 4. No significant association with any of these variants was found, when compared to the frequencies of the variants in a healthy control cohort. Furthermore, the mutated alleles R20C and R72H did not segregate with the SLE phenotype in familial cases of SLE. Thus, our evaluation of the coding region of TNFRSF13b/TACI did not reveal any deleterious or disease-associated mutations. Inga Melchers and Bodo Grimbacher contributed equally to this work.     

In Vitro Pharmacodynamic Studies of L-749,345 in Comparison with Imipenem and Ceftriaxone against Gram-Positive and Gram-Negative Bacteria

L-749,345 is a new parenteral carbapenem with a very long half-life similar to that of ceftriaxone. The aim of the present study was to investigate different pharmacodynamic parameters of L-749,345 in comparison with those of ceftriaxone and imipenem. The following studies were performed: (i) comparative studies of the MICs of L-749,345, imipenem, and ceftriaxone for 70 strains of gram-positive and gram-negative bacteria; (ii) comparative studies of the rate of killing of gram-positive and gram-negative bacteria by L-749,345, imipenem, and ceftriaxone; (iii) studies of the postantibiotic effects of L-749,345, imipenem, and ceftriaxone; and (iv) studies of the postantibiotic sub-MIC effects of L-749,345, imipenem, and ceftriaxone. Significantly lower MICs of L-749,345 compared with those of ceftriaxone were found for all gram-negative organisms except Haemophilus influenzae. The MICs of L-749,345 were similar to those of imipenem for all organisms except Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus, for which the MICs of L-749,345 were higher. A concentration-dependent killing of methicillin-resistant S. aureus but not methicillin-susceptible strains was noted for both L-749,345 and imipenem. All three of the investigated drugs exhibited a postantibiotic effect against the gram-positive strains but exhibited no postantibiotic effect against the gram-negative strains.     

Activities of naphthylisoquinoline alkaloids and synthetic analogs against Leishmania major

The current treatments for leishmaniasis are unsatisfactory due to their toxic side effects, high costs, and increasing problems with drug resistance. Thus, there is an urgent need for alternative drugs against leishmaniasis. Different approaches have been used to identify novel pharmacophores against Leishmania sp. parasites, and one strategy has been the analysis of naturally occurring plant-derived compounds, including naphthylisoquinoline alkaloids. In the present study, we examined the abilities of these alkaloids to inhibit the growth of Leishmania major promastigotes and evaluated their effects on macrophages, dendritic cells, and fibroblasts. Furthermore, we determined the efficacy of selected compounds in decreasing the infection rate of macrophages and regulating their production of cytokines and nitric oxide. Our results demonstrate that the naphthylisoquinoline alkaloids ancistrocladiniums A and B (compounds 10 and 11) and the synthetic isoquinolinium salt (compound 14) were effective against intracellular amastigotes in the low submicromolar range, while toxicity against mammalian cells was observed at concentrations that were significantly higher than those needed to impair parasite replication. The activities of compounds 11 and 14 were mainly directed against the amastigote stage of L. major. This effect was not associated with the stimulation of host macrophages to produce nitric oxide or secrete cytokines relevant for the leishmanicidal function. In conclusion, our data suggest that ancistrocladiniums A and B (compounds 10 and 11) and the synthetically prepared isoquinolinium salt (compound 14) are promising candidates to be considered as lead compounds for leishmanicidal drugs.     

Patient participation in nursing care from a patient perspective: a Grounded Theory study

The study's rationale: Patients’ active participation in their own care is expected to contribute to increased motivation to improve their own condition, better treatment results and greater satisfaction with received care. Knowledge of patients’ understanding of participation is of great importance for nurses in their efforts to meet patient expectations and for quality of nursing care. Aim: The aim was to explore the meaning of patient participation in nursing care from a patient point of view. Methodological design and justification: Six tape‐recorded focus group interviews with 26 Swedish informants described opinions on and experiences of patient participation. The informants consisted of patients in somatic inpatient care as well as discharged patients from such a setting. The Grounded Theory method was used and the data were analysed using constant comparative analysis. Ethical issues and approval: The ethics of scientific work was followed. Each study participant gave informed consent after verbal and written information. The Ethics Committee of Göteborg University approved the study. Findings: The patients emphasised the importance of collaboration to improve participation. The core category, Insight through consideration, was generated from four inter‐related categories: (i) Obliging atmosphere; (ii) Emotional response; (iii) Concordance; and (iv) Rights and their 15 subcategories. Conclusions: The meaning structures of patient participation in nursing care revealed from a patient point of view, seemed to mainly consist of not only external factors presented by the institutions – by the professionals – but also internal patient factors. The patients’ view of participation should be considered to a greater degree in nursing practice and education, as should also further development of nursing care policy programmes, evaluation and quality assurance criteria. For further development, studies are needed in similar and other settings.     

Oropharyngeal Dysphagia and Impaired Motility of the Upper Gastrointestinal Tract—Is There a Clinical Link in Neurocritical Care?

Patients in the neurological ICU are at risk of suffering from disorders of the upper gastrointestinal tract. Oropharyngeal dysphagia (OD) can be caused by the underlying neurological disease and/or ICU treatment itself. The latter was also identified as a risk factor for gastrointestinal dysmotility. However, its association with OD and the impact of the neurological condition is unclear. Here, we investigated a possible link between OD and gastric residual volume (GRV) in patients in the neurological ICU. In this retrospective single-center study, patients with an episode of mechanical ventilation (MV) admitted to the neurological ICU due to an acute neurological disease or acute deterioration of a chronic neurological condition from 2011–2017 were included. The patients were submitted to an endoscopic swallowing evaluation within 72 h of the completion of MV. Their GRV was assessed daily. Patients with ≥1 d of GRV ≥500 mL were compared to all the other patients. Regression analysis was performed to identify the predictors of GRV ≥500 mL/d. With respect to GRV, the groups were compared depending on their FEES scores (0–3). A total of 976 patients were included in this study. A total of 35% demonstrated a GRV of ≥500 mL/d at least once. The significant predictors of relevant GRV were age, male gender, infratentorial or hemorrhagic stroke, prolonged MV and poor swallowing function. The patients with the poorest swallowing function presented a GRV of ≥500 mL/d significantly more often than the patients who scored the best. Conclusions: Our findings indicate an association between dysphagia severity and delayed gastric emptying in critically ill neurologic patients. This may partly be due to lesions in the swallowing and gastric network.     

Novel human p53 mutations that are toxic to yeast can enhance transactivation of specific promoters and reactivate tumor p53 mutants.

Since highly expressed human p53 can inhibit human and yeast cell growth, we predicted that p53 mutants could be generated with increased growth inhibition of the yeast Saccharomyces cerevisiae and that these would be useful for characterizing p53 functions and tumor p53 mutants. A random mutagenesis screen led to the isolation of mutations in the DNA binding domain that result in p53 being lethal even at moderate expression levels in yeast. Three independent mutants had an alanine change at the evolutionary invariant V122 in the L1 loop. The other toxic mutations affected codons 277 (C277R, C277W) and 279 (G279R). This latter amino acid change was also reported in tumors, while all the other mutations are novel. A recently developed rheostatable GALI promoter system that provides graded increases in expression of p53 was used to examine the transactivation function of the toxic mutations when expression was greatly reduced and cells were viable. At low expression levels the toxic mutants lacked transactivation from a 3xRGC responsive element (RE). Surprisingly some exhibited enhanced transactivation with p21 and bax REs. The V122A mutant was able to re-activate transactivation of various p53 tumor mutants and retained growth inhibition when co-expressed with dominant-negative tumor mutations. Upon expression in human Saos-2 cells the V122A p53 mutant caused growth suppression, was capable of transactivation and exhibited higher than wild type activity with the bax promoter in luciferase assays. A non-functional p53 tumor mutant was partially reactivated by V122A for both transactivation and growth suppression. Thus, the screen for toxic p53 mutants in yeast can identify novel p53 variants that may be useful in dissecting p53 regulated cellular responses and in developing p53-based cancer therapies.     

An isolated perfused pig heart model for the development,validation and translation of novel cardiovascular magnetic resonance techniques

Background

Novel cardiovascular magnetic resonance (CMR) techniques and imaging biomarkers are often validated in small animal models or empirically in patients. Direct translation of small animal CMR protocols to humans is rarely possible, while validation in humans is often difficult, slow and occasionally not possible due to ethical considerations. The aim of this study is to overcome these limitations by introducing an MR-compatible, free beating, blood-perfused, isolated pig heart model for the development of novel CMR methodology.

Methods

6 hearts were perfused outside of the MR environment to establish preparation stability. Coronary perfusion pressure (CPP), coronary blood flow (CBF), left ventricular pressure (LVP), arterial blood gas and electrolyte composition were monitored over 4 hours. Further hearts were perfused within 3T (n = 3) and 1.5T (n = 3) clinical MR scanners, and characterised using functional (CINE), perfusion and late gadolinium enhancement (LGE) imaging. Perfusion imaging was performed globally and selectively for the right (RCA) and left coronary artery (LCA). In one heart the RCA perfusion territory was determined and compared to infarct size after coronary occlusion.

Results

All physiological parameters measured remained stable and within normal ranges. The model proved amenable to CMR at both field strengths using typical clinical acquisitions. There was good agreement between the RCA perfusion territory measured by selective first pass perfusion and LGE after coronary occlusion (37% versus 36% of the LV respectively).

Conclusions

This flexible model allows imaging of cardiac function in a controllable, beating, human-sized heart using clinical MR systems. It should aid further development, validation and clinical translation of novel CMR methodologies, and imaging sequences.