Regulation of murine dendritic cell functions in vitro by taurine chloramine, a major product of the neutrophil myeloperoxidase-halide system

Taurine chloramine (TauCl) is a major chloramine generated in activated neutrophils as a result of the reaction of highly toxic hypochlorous acid and taurine, the most abundant free amino acid in cytosol. In this study we have tested the influence of TauCl on the properties of murine dendritic cells (DC), the major cell population involved in the initiation of an adaptive immune response against pathogenic organisms. N418+, MHC II+, B7-2+ dendritic cells, generated from the mouse bone marrow cells cultured in the presence of granulocyte-macrophage colony-stimulating factor, were stimulated by interferon-gamma and lipopolysaccharide to produce nitric oxide, reactive oxygen species, interleukin-6 (IL-6), tumour necrosis factor-alpha, and IL-12, in the presence of different doses of TauCl. TauCl differently inhibited the generation of these inflammatory mediators in a dose-dependent manner. Furthermore, TauCl selectively modulated the ability of DC to induce the release IL-2 and IL-10 from T cells. These results suggest that neutrophil-derived mediators, such as TauCl, at a site of inflammation, may affect the functions of sentinel DC and macrophages, and play a role in maintaining the balance between the inflammatory response and the induction of an antigen-specific immune response.     

Cancer immunotherapy based on killing of Salmonella-infected tumor cells

A major obstacle for the development of effective immunotherapy is the ability of tumors to escape the immune system. The possibility to kill tumor cells because they are recognized as infected rather than as malignant could help overcome immune escape mechanisms. Here we report a conceptually new approach of cancer immunotherapy based on in vivo infection of tumors and killing of infected tumor cells. Attenuated but still invasive, Salmonella typhimurium can be successfully exploited to invade melanoma cells that can present antigenic determinants of bacterial origin and become targets for anti-Salmonella-specific T cells. However, to fully appreciate the anticancer therapeutic properties of S. typhimurium, tumor-bearing mice need to be vaccinated against S. typhimurium before intratumoral Salmonella injection. Tumor infection when coupled to anti-Salmonella vaccination leads to 50% to 100% tumor-free mice with a better outcome on larger tumors. Invasive Salmonella also exert an indirect toxic effect on tumor cells through the recruitment of inflammatory cells and the cross-presentation of tumor antigens, which allow induction of tumor-specific immune response. This is effective in retarding the growth of untreated established distant tumors and in protecting the mice from subsequent tumor challenges.     

Mongolian spots with involvement of mandibular area

A 1-year-old boy had grayish pigmentation on the left side of his face over the area supplied by the mandibular branch of the trigeminal nerve. Upon further examination, the lesion was also found on the left side of the neck, shoulder, upper arm, right lower back and buttock. The pigmentation was uniform in intensity. This case report demonstrates that Mongolian spots can occur on the face in the area supplied by the mandibular branch of the trigeminal nerve. These spots should not be misdiagnosed as nevus of Ota.     

Changes in the Health of Adolescent Athletes: A Comparison of Health Measures Collected Before and During the COVID-19 Pandemic

ContextIn spring 2020, schools closed to in-person teaching and sports were cancelled to control the transmission of COVID-19. The changes that affected the physical and mental health among young athletes during this time remain unknown.ObjectiveTo identify changes in the health (mental health, physical activity, and quality of life) of athletes that occurred during the COVID-19 pandemic.DesignCross-sectional study.SettingSample recruited via social media.Patients or Other ParticipantsA total of 3243 Wisconsin adolescent athletes (age = 16.2 ± 1.2 years, 58% female) were surveyed in May 2020 (During COVID-19). Measures for this cohort were compared with previously reported data for Wisconsin adolescent athletes (n = 5231; age = 15.7 ± 1.2 years, 47% female) collected in 2016 to 2018 (PreCOVID-19).Main Outcome Measure(s)Demographic information included sex, grade, and sport(s) played. Health assessments included the Patient Health Questionnaire-9 Item to identify depression symptoms, the Pediatric Functional Activity Brief Scale to gauge physical activity, and the Pediatric Quality of Life Inventory 4.0 to evaluate health-related quality of life. Univariable comparisons of these variables between groups were conducted via t or χ² tests. Means and 95% CIs for each group were estimated using survey-weighted analysis-of-variance models.ResultsCompared with preCOVID-19 participants, a larger proportion of During COVID-19 participants reported moderate to severe levels of depression (9.7% versus 32.9%, P < .001). Scores of the During COVID-19 participants were 50% lower (worse) on the Pediatric Functional Activity Brief Scale (mean [95% CI] = 12.2 [11.9, 12.5] versus 24.7 [24.5, 24.9], P < .001) and the Pediatric Quality of Life Inventory 4.0 compared with the PreCOVID-19 participants (78.4 [78.0, 78.8] versus 90.9 [90.5, 91.3], P < .001).ConclusionsDuring the COVID-19 pandemic, adolescent athletes described increased symptoms of depression, decreased physical activity, and decreased quality of life compared with adolescent athletes in previous years.     

Wheat germ agglutinin-conjugated chitosan–Ca–alginate microparticles for local colon delivery of 5-FU: Development and in vitro characterization

The aim of this work was to prepare lectin-conjugated chitosan–Ca–alginate microparticles (MPs) loaded with acid-resistant particles of 5-fluorouracil (5-FU) for efficient local treatment of colon cancer. MPs were prepared by a novel one-step spray-drying technique and after wheat germ agglutinin (WGA) conjugation, they were characterized for size, swelling behavior, surface charge, entrapment efficiency and in vitro drug release. Prepared particles were spherical, with 6.73 μg/mg of WGA conjugated onto their surface. The size and zeta potential increased after conjugation, from 6.6 to 14.7 μm and from 9.6 to 15.3 mV, while drug encapsulation was 75.6 and 72.8%, respectively after conjugation. The swelling behavior of beads was mainly determined by properties of the cross-linked chitosan–alginate network. In vitro drug release studies carried out in simulated in vivo conditions with respect to pH, confirmed the potential of the particles to release the drug in a controlled manner. Also, the drug release was not significantly affected by WGA conjugation. The retention of biorecognitive activity of WGA after covalent coupling to MPs was confirmed by haemagglutination test. Functionalized MPs showed excessive mucoadhesiveness in vitro, due to the positive surface charge, pH-dependent swelling of the matrix and lectin–sugar recognition.     

Investigations on the pharmacology of the cardioprotective guanidine ME10092

The guanidine compound ME10092 (1-(3,4-dimethoxy-2-chlorobenzylideneamino)-guanidine), which possesses a strong cardioprotective effect to ischemia-reperfusion, was assessed for different pharmacological actions that may underlie its cardioprotective effect. In the living rat ME10092 decreased the blood pressure and heart rate in a dose-dependent manner. We found ME10092 to bind to alpha 1- and alpha 2-adrenoreceptors with moderate affinity (Ki values 1-4 microM), and to block adrenaline-elicited contractile responses in isolated guinea pig aortas. Our results indicate that ME10092 possesses a certain anti-oxidant profile. Thus, in a competitive manner and with low affinity it inhibited the bovine milk xanthine oxidase enzyme, as well as NAD(P)H oxidase driven oxyradical formation in membrane fractions isolated from the rat brain. By using electron paramagnetic resonance we here show that, after its systemic administration, ME10092 modulates the nitric oxide (NO) content in several tissues of the rat in a time-dependent manner. However, in vitro ME10092 inhibited the activities of nitric oxide synthases nNOS and eNOS, but not that of iNOS. Our data give evidence that the cardioprotective effect of ME10092 could be mediated through pharmacological mechanisms that include some modulation of NO production, as well as possible inhibition of radical formation during ischemia-reperfusion.     

Co-operative regulation of ligand binding to melanocortin receptor subtypes: evidence for interacting binding sites

This study evaluates the binding the melanocyte stimulating hormone peptide analogue [125I]NDP-MSH to melanocortin receptors MC1, MC3, MC4 and MC5 in insect cell membranes produced by baculovirus expression systems. The presence of Ca2+ was found to be mandatory to achieve specific [125I]NDP-MSH binding to the melanocortin receptors. Although association kinetics of [125I]NDP-MSH followed the regularities of simple bimolecular reactions, the dissociation of [125I]NDP-MSH from the melanocortin receptors was heterogeneous. Eleven linear and cyclic MSH peptides studied displaced the [125I]NDP-MSH binding to the studied melanocortin receptors, with the shapes of their competition curves varying from biphasic or shallow to super-steep (Hill coefficients ranging from 0.4 to 1.5). Notably the same peptide often gave highly different patterns on different melanocortin receptor subtypes; e.g. the MC4 receptor selective antagonist HS131 gave a Hill coefficient of 1.5 on the MC1 receptor but 0.5-0.7 on the MC(3-5) receptors. Adding a mask of one of the peptides to block its high affinity binding did not prevent other competing peptides to yield biphasic competition curves. The data indicate that the binding of MSH peptides to melanocortin receptors are governed by a complex dynamic homotropic co-operative regulations.     

Modulation of dendritic cell endocytosis and antigen processing pathways by Escherichia coli heat-labile enterotoxin and mutant derivatives

Escherichia coli heat-labile enterotoxin (LT) is known to be a potent adjuvant of both the mucosal and systemic immune systems but the mechanism of action leading to adjuvant activity remains incompletely understood. This study investigates the action of LT and LT mutants with impaired enzymatic activity, on the function of dendritic cells. Wild-type LT and LTR72, which retains some ADP ribosyltransferase activity, induced a selective increase in cell surface expression of B7.1, and a selective decrease of CD40 expression on mouse bone marrow derived dendritic cells. LTK63 and LT-B had no obvious effect on the expression of these antigens on similar dendritic cells. LT-treated dendritic cells also showed a profoundly impaired ability to present protein antigen (ovalbumin) to cognate T cells, although this effect was not observed with non-toxic LT mutants. LT and LTR72-treated cells showed a slower rate of receptor-mediated endocytosis as measured by flow cytometric analysis of uptake of fluorescently labelled dextran. Furthermore, confocal microscopy showed changes in the intracellular distribution of endocytosed molecules, and of the class II containing acidic antigen processing compartments. This response of dendritic cells to toxin is likely to play an important role in determining the adjuvant activity of these molecules.     

Microevolution of Monophasic Salmonella Typhimurium during Epidemic,United Kingdom, 2005–2010

Microevolution associated with emergence and expansion of new epidemic clones of bacterial pathogens holds the key to epidemiologic success. To determine microevolution associated with monophasic Salmonella Typhimurium during an epidemic, we performed comparative whole-genome sequencing and phylogenomic analysis of isolates from the United Kingdom and Italy during 2005–2012. These isolates formed a single clade distinct from recent monophasic epidemic clones previously described from North America and Spain. The UK monophasic epidemic clones showed a novel genomic island encoding resistance to heavy metals and a composite transposon encoding antimicrobial drug resistance genes not present in other Salmonella Typhimurium isolates, which may have contributed to epidemiologic success. A remarkable amount of genotypic variation accumulated during clonal expansion that occurred during the epidemic, including multiple independent acquisitions of a novel prophage carrying the sopE gene and multiple deletion events affecting the phase II flagellin locus. This high level of microevolution may affect antigenicity, pathogenicity, and transmission.