Mycoplasma pneumoniae Compared to Streptococcus pneumoniae Avoids Induction of Proinflammatory Epithelial Cell Responses despite Robustly Inducing TLR2 Signaling.

Mycoplasma pneumoniae and Streptococcus pneumoniae are the most common bacterial causes of pneumonia in children. The clinical characteristics of pneumonia differ significantly between the two bacteria. We aimed to elucidate the differences in pathogenesis between M. pneumoniae and S. pneumoniae by characterizing the respiratory epithelial cell immune response to both pathogens. Using primary human bronchial epithelial cells in air-liquid interface cultures, we observed lower production of the proinflammatory cytokines interleukin-6 (IL-6) and IL-8 in response to M. pneumoniae than to S. pneumoniae. In contrast to the differences in proinflammatory cytokine production, Toll-like receptor 2 (TLR2)-mediated signaling in response to M. pneumoniae was stronger than to S. pneumoniae. This difference largely depended on TLR1 and not TLR6. We found that M. pneumoniae, but not S. pneumoniae, also induced signaling of TLR10, a coreceptor of TLR2 that has inhibitory properties. M. pneumoniae-induced TLR10 signaling on airway epithelial cells was partially responsible for low IL-8 production, as blocking TLR10 by specific antibodies increased cytokine production. M. pneumoniae maintained Th2-associated cytokine production by epithelial cells, which concurs with the known association of M. pneumoniae infection with asthma. M. pneumoniae left IL-33 levels unchanged, whereas S. pneumoniae downregulated IL-33 production both under homeostatic and Th2-promoting conditions. By directly comparing M. pneumoniae and S. pneumoniae, we demonstrate that M. pneumoniae avoids induction of proinflammatory cytokine response despite its ability to induce robust TLR2 signaling. Our new findings suggest that this apparent paradox may be partially explained by M. pneumoniae-induced signaling of TLR2/TLR10.

A Water-Soluble Iridium Photocatalyst for Chemical Modification of Dehydroalanines in Peptides and Proteins.

Dehydroalanine (Dha) residues are attractive noncanonical amino acids that occur naturally in ribosomally synthesised and post-translationally modified peptides (RiPPs). Dha residues are attractive targets for selective late-stage modification of these complex biomolecules. In this work, we show the selective photocatalytic modification of dehydroalanine residues in the antimicrobial peptide nisin and in the proteins small ubiquitin-like modifier (SUMO) and superfolder green fluorescent protein (sfGFP). For this purpose, a new water-soluble iridium(III) photoredox catalyst was used. The design and synthesis of this new photocatalyst, [Ir(dF(CF3 )ppy)2 (dNMe3 bpy)]Cl3 , is presented. In contrast to commonly used iridium photocatalysts, this complex is highly water soluble and allows peptides and proteins to be modified in water and aqueous solvents under physiologically relevant conditions, with short reaction times and with low reagent and catalyst loadings. This work suggests that photoredox catalysis using this newly designed catalyst is a promising strategy to modify dehydroalanine-containing natural products and thus could have great potential for novel bioconjugation strategies.

Differential effects of long-term aerobic versus cognitively-engaging physical activity on children's visuospatial working memory related brain activation: A cluster RCT.

Different types of physical activity are thought to differentially affect children's brain activation, via physiological mechanisms, or by activating similar brain areas during physical and cognitive tasks. Despite many behavioral studies relying on these mechanisms, they have been rarely studied. This study looks at both mechanisms simultaneously, by examining effects of two physical activity interventions (aerobic vs. cognitively-engaging) on children's brain activation. Functional Magnetic Resonance Imaging (fMRI) data of 62 children (48.4% boys, mean age 9.2 years) was analyzed. Children's visuospatial working memory related brain activity patterns were tested using a Spatial Span Task before and after the 14-week interventions consisting of four physical education lessons per week. The control group followed their regular program of two lessons per week. Analyses of activation patterns in SPM 12.0 revealed no activation changes between pretest and posttest (p > .05), and no differences between the three conditions in pretest-posttest changes in brain activation (p > .05). Large inter-individual differences were found, suggesting that not every child benefited from the interventions in the same way. To get more insight into the assumed mechanisms, further research is needed to understand whether, when, for whom, and how physical activity results in changed brain activation patterns.

Relationships between gross motor skills, cardiovascular fitness, and visuospatial working memory-related brain activation in 8- to 10-year-old children.

Relationships between gross motor skills and cardiovascular fitness with visuospatial working memory (VSWM) in children are hypothesized to be mediated by underlying functional brain mechanisms. Because there is little experimental evidence to support this mechanism, the present study was designed to investigate the relationships of gross motor skills and cardiovascular fitness with VSWM-related brain activation in 8- to 10-year-old children. Functional magnetic resonance imaging data obtained during a VSWM-task were analyzed for 80 children from grades 3 (47.5%) and 4 of 21 primary schools in the Netherlands (51.3% girls). Gross motor skills (Korper Koordinationstest für Kinder and Bruininks-Oseretsky Test of Motor Proficiency - 2nd Edition) and cardiovascular fitness (20-meter Shuttle Run Test) were assessed. VSWM-related brain activation was found in a network involving the angular gyrus, the superior parietal cortex, and the thalamus; deactivation was found in the inferior and middle temporal gyri. Although behavioral results showed significant relations of gross motor skills and cardiovascular fitness with VSWM performance, gross motor skills and cardiovascular fitness were not related to VSWM-related brain activation. Therefore, we could not confirm the hypothesis that brain activation underlies the relationship of gross motor skills and cardiovascular fitness with VSWM performance. Our results suggest that either the effects of physical activity on cognition do not necessarily go via changes in gross motor skills and/or cardiovascular fitness, or that brain activation patterns as measured with the blood-oxygen-level dependent (BOLD) signal may not be the mechanism underlying the relationships of gross motor skills and cardiovascular fitness with VSWM.

Catalytic Modification of Dehydroalanine in Peptides and Proteins by Palladium-Mediated Cross-Coupling.

Dehydroalanine (Dha) is a remarkably versatile non-canonical amino acid often found in antimicrobial peptides. Herein, we present the catalytic modification of Dha by a palladium-mediated cross-coupling reaction. By using Pd(EDTA)(OAc)2 as water-soluble catalyst, a variety of arylboronic acids was coupled to the dehydrated residues in proteins and peptides, such as Nisin. The cross-coupling reaction gave both the Heck product, in which the sp2 -hybridisation of the α-carbon is retained, as well as the conjugated addition product. The reaction can be performed under mild aqueous conditions, which makes this method an attractive addition to the palette of bio-orthogonal catalytic methods.

Chemical Modification of Dehydrated Amino Acids in Natural Antimicrobial Peptides by Photoredox Catalysis.

Dehydroalanine (Dha) and dehydrobutyrine (Dhb) are remarkably versatile non-canonical amino acids often found in antimicrobial peptides. This work presents the selective modification of Dha and Dhb in antimicrobial peptides through photocatalytic activation of organoborates under the influence of visible light. Ir(dF(CF3 )ppy)2 (dtbbpy)PF6 was used as a photoredox catalyst in aqueous solutions for the modification of thiostrepton and nisin. The mild conditions and high selectivity for the dehydrated residues show that photoredox catalysis is a promising tool for the modification of peptide-derived natural products.

Exploring the relations among physical fitness, executive functioning, and low academic achievement.

Physical fitness seems to be related to academic performance, at least when taking the role of executive functioning into account. This assumption is highly relevant for the vulnerable population of low academic achievers because their academic performance might benefit from enhanced physical fitness. The current study examined whether physical fitness and executive functioning are independent predictors of low mathematics and spelling achievement or whether the relation between physical fitness and low achievement is mediated by specific executive functions. In total, 477 students from second- and third-grade classes of 12 primary schools were classified as either low or average-to-high achievers in mathematics and spelling based on their scores on standardized achievement tests. Multilevel structural equation models were built with direct paths between physical fitness and academic achievement and added indirect paths via components of executive functioning: inhibition, verbal working memory, visuospatial working memory, and shifting. Physical fitness was only indirectly related to low achievement via specific executive functions, depending on the academic domain involved. Verbal working memory was a mediator between physical fitness and low achievement in both domains, whereas visuospatial working memory had a mediating role only in mathematics. Physical fitness interventions aiming to improve low academic achievement, thus, could potentially be successful. The mediating effect of executive functioning suggests that these improvements in academic achievement will be preceded by enhanced executive functions, either verbal working memory (in spelling) or both verbal and visuospatial working memory (in mathematics).

[Usefulness of repetitive transcranial magnetic stimulation (rTMS) in the treatment of bipolar depression]. / Repetitieve transcraniële magnetische stimulatie (rTMS) als behandeling van bipolaire depressie.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) has been found to be an effective technique in the treatment of unipolar depression. However, it is not yet clear whether rTMS is also useful in the treatment of bipolar depression. AIM: To evaluate the available evidence that rTMS is effective in the treatment of bipolar depression. METHOD: Review of available literature (RCTs and open-label studies). RESULTS: We looked closely at four RCTs and four open-label studies. In three of the four RCTs the results for patients who had received rTMS were no better than those for patients who had received a placebo. Patients in all four open-label studies showed significant improvement. One individual developed hypomanic symptoms. The studies used many different parameters; some studies included diagnoses, some referred to the type of medication used. CONCLUSION: So far, there is a lack of high quality studies on which we can base our conclusions about the effectiveness of rTMS for the treatment of bipolar depression. The use of rTMS to treat patients with bipolar depression does not seem to increase the risk that a patient will develop (hypo)mania.

Modulation of charge transport across double-stranded DNA by the site-specific incorporation of copper bis-phenanthroline complexes.

The site-specific incorporation of transition-metal complexes within DNA duplexes, followed by their immobilization on a gold surface, was studied by electrochemistry to characterize their ability to mediate charge. Cyclic voltammetry, square-wave voltammetry, and control experiments were carried out on fully matched and mismatched DNA strands that are mono- or bis-labeled with transition-metal complexes. These experiments are all consistent with the ability of the metal centers to act as a redox probe that is well coupled to the DNA π-stack, allowing DNA-mediated charge transport.

A randomized controlled trial of a standard 4-week protocol of repetitive transcranial magnetic stimulation in severe treatment resistant depression.

BACKGROUND: Treatment options for major depressive disorder (MDD) in individuals who are depressed for at least 2 years and failed two or more different types of therapeutic intervention, remain scarce. Being less invasive than electroconvulsive therapy, repetitive transcranial magnetic stimulation (rTMS) might be an alternative treatment option. RESEARCH QUESTION: Does high frequency rTMS applied over the left prefrontal cortex ameliorate depressive symptoms in patients with treatment resistant major depressive disorder and is the efficacy dependent on treatment resistance? METHOD: We performed a randomized controlled trial investigating the effect of twenty sessions of real or sham-rTMS, during 4 consecutive weeks. Efficacy was blindly rated with the Hamilton depression rating scale (HDRS-17) at baseline and 1 week after end of treatment, and the Dutch method for quantification of treatment resistance in Depression (DM-TRD) was assessed at baseline. RESULTS: An interim analysis showed no differences in antidepressant response between real and sham rTMS and we therefore discontinued the RCT after 31 patients. The mean difference of the HDRS score between baseline and post-treatment was 3.7 (± 4.0; change 16%), indicating a small but significant improvement across time (F(1,30)=25.4;p < 0.01). There were no differences however between the treatment arms (F(1.30) = 1.5;p = 0.23). We did find a negative correlation between the change in HDRS score and DM-TRD in the active rTMS group, but this correlation was not significantly different from the sham group. CONCLUSION: "Standard" 4-week rTMS treatment is not effective in chronic, severe treatment-resistant depressed patients. While a replication of our data in this patient group may be ethically difficult, further research with less treatment resistant patients might help in positioning rTMS within the current stepped care approach to depression.

Multinuclear non-heme iron complexes for double-strand DNA cleavage.

The cytotoxicity of the anti-tumor drug BLM is believed to be related to the ability of the corresponding iron complex (Fe-BLM) to engage in oxidative double-strand DNA cleavage. The iron complex of the ligand N4Py (Fe-N4Py; N4Py = N,N-bis(2-pyridyl)-N-bis(2-pyridyl)methylamine) has proven to be a particularly valuable spectroscopic and functional model for Fe-BLM. It is also a very active oxidative DNA-cleaving agent. However, like all other synthetic Fe-BLM mimics, it gives only single-strand DNA cleavage. Since double-strand DNA cleavage requires the delivery of two oxidizing equivalents to the DNA, it was envisaged that multinuclear iron complexes might be capable of effecting double-strand cleavage. For this purpose, a series of ditopic and tritopic N4Py-derived ligands has been synthesized and the corresponding iron complexes have been evaluated for their efficacy in the oxidative cleavage of supercoiled pUC18 plasmid DNA. The dinuclear iron complexes showed significantly enhanced double-strand cleavage activity compared to mononuclear Fe-N4Py, which was relatively independent of the structure of the linking moiety. Covalent attachment of a 9-aminoacridine intercalator to a dinuclear complex did not give rise to improved double-strand DNA cleavage. The most efficient oxidative double-strand cleavage agents proved to be the trinuclear iron complexes. This is presumably the result of increased probability of the simultaneous delivery of two oxidizing equivalents to the DNA.

Characterization of Membrane Properties in Desiccation-Tolerant and -Intolerant Carrot Somatic Embryos.

In previous studies, we have shown that carrot (Daucus carota L.) somatic embryos acquire complete desiccation tolerance when they are treated with abscisic acid during culture and subsequently dried slowly. With this manipulable system at hand, we have assessed damage associated with desiccation intolerance. Fast drying caused loss of viability, and all K+ and carbohydrates leached from the somatic embryos within 5 min of imbibition. The phospholipid content decreased by about 20%, and the free fatty acid content increased, which was not observed after slow drying. However, the extent of acyl chain unsaturation was unaltered, irrespective of the drying rate. These results indicate that, during rapid drying, irreversible changes occur in the membranes that are associated with extensive leakage and loss of germinability. The status of membranes after 2 h of imbibition was analyzed in a freeze-fracture study and by Fourier transform infrared spectroscopy. Rapidly dried somatic embryos had clusters of intramembraneous particles in their plasma membranes, and the transition temperature of isolated membranes was above room temperature. Membrane proteins were irreversibly aggregated in an extended [beta]-sheet conformation and had a reduced proportion of [alpha]-helical structures. In contrast, the slowly dried somatic embryos had irregularly distributed, but non-clustered, intramembraneous particles, the transition temperature was below room temperature, and the membrane proteins were not aggregated in a [beta]-sheet conformation. We suggest that desiccation sensitivity of rapidly dried carrot somatic embryos is indirectly caused by an irreversible phase separation in the membranes due to de-esterification of phospholipids and accumulation of free fatty acids.

Reduction of blood pressure with oral magnesium supplementation in women with mild to moderate hypertension.

In a double-blind controlled trial, 91 middle-aged and elderly women with mild to moderate hypertension who were not on antihypertensive medication were randomly assigned to treatment with magnesium aspartate-HCl (20 mmol Mg/d) or placebo for 6 mo. Magnesium aspartate-HCl in the given dose was well-tolerated and was not associated with an increased frequency of diarrhea compared with placebo. At the end of the study, systolic blood pressure had fallen by 2.7 mm Hg (95% CI -1.2, 6.7; P = 0.18) and diastolic blood pressure by 3.4 mm Hg (1.3, 5.6; P = 0.003) more in the magnesium group than in the placebo group. Blood pressure response was not associated with baseline magnesium status, as measured by dietary magnesium intake and urinary magnesium excretion. Urinary magnesium excretion in the magnesium group increased by 50% during the intervention period. No changes were seen in other biochemical indexes, including serum concentrations of total and high-density-lipoprotein cholesterol. The findings suggest that oral supplementation with magnesium aspartate-HCl may lower blood pressure in subjects with mild to moderate hypertension.

Serum selenium, vitamin antioxidants, and cardiovascular mortality: a 9-year follow-up study in the Netherlands.

The association between low serum selenium, vitamin A, and vitamin E levels and mortality from cardiovascular disease (CVD) was investigated in a case-control study nested in a 9-yr prospective study in the Netherlands. For 10,532 persons aged greater than or equal to 5 yr who participated in a 1975-1978 medical survey, serum was stored at -20 degrees C. For the 84 of 106 subjects aged 37-87 yr who died of CVD after the baseline exam, 168 cohort members alive at the end of 1983 and matched for age and gender were selected as controls. No significant associations between serum selenium. vitamin A, vitamin E, and CVD mortality were observed before and after multivariate analyses. The adjusted risk of death from CVD for subjects in the lowest selenium quintile (less than 105.0 micrograms/L) was 1.6 (95% CI, 0.8-3.2). For coronary and stroke death risk, estimates were 1.1 (95% CI, 0.5-2.6) and 3.2 (95% CI, 0.8-12.1). Our findings do not show a clear CVD risk from low selenium and vitamin levels. Although some of the risk estimates were strong, larger studies are required for definitive conclusions.

Lipoproteins and apolipoproteins in the young and familial risk of coronary atherosclerosis.

The aim of this study was to assess the predictive value of lipoproteins and apolipoproteins at a young age for the development of coronary artery disease at middle and older ages. Because children of coronary artery disease patients are at high risk themselves we compared lipoprotein and apolipoprotein levels between the offspring of parents with and without coronary artery disease. We selected a group of male patients (n = 90), who had severe coronary atherosclerosis at angiography, and a reference group of male controls (n = 62), who had no coronary atherosclerosis at angiography. Lipoprotein and apolipoprotein levels were determined in 115 sons and 73 daughters of the patients with severe coronary atherosclerosis. These were compared to levels in 68 sons and 47 daughters of controls. Additionally, lipoprotein and apolipoprotein levels were compared between patients and controls as well as between their spouses. In sons of patients, lower levels of HDL3 cholesterol (-0.07 mmol/1, standard error of the mean (SEM) 0.03, P < 0.05) and apolipoprotein A2 (-5.1 mg/dl (SEM, 1.4), P < 0.0001) were found compared to sons of controls. Similar differences were observed in daughters of such patients without, however, achieving statistical significance. No significant differences between the groups of offspring were found for total cholesterol, LDL cholesterol, HDL and HDL2 cholesterol, triglycerides and apolipoproteins A-I and B. Patients had higher levels of total (group difference 0.6 mmol/1 (SEM, 0.18), P < 0.001) and LDL cholesterol (0.6 mmol/1 (SEM, 0.17), P < 0.001), triglycerides (0.6 mmol/1 (SEM, 0.16), P < 0.001) and apolipoprotein B (21.2 mg/dl (SEM, 5.1), P < 0.001), and lower HDL cholesterol (0.1 mmol/1 (SEM, 0.04), P < 0.05) than controls. Spouses of patients had higher levels of triglycerides (0.23 mmol/1 (SEM, 0.11), P < 0.05). Our findings add to the growing evidence that predictors for atherosclerotic disease can be detected relatively early in life. It is concluded that reduced levels of HDL3 cholesterol and apolipoprotein A2 may be early risk indicators for coronary atherosclerosis later in life.

The effect of the diffusion medium on quantification of human IgM by radial immunodiffusion.

The results of quantification of human IgM by radial immunodiffusion (RID) are influenced by the charge of the diffusion medium and by the radio of IgM to other serum proteins. Agarose has almost no influence, while some heavily charged agars are unsuitable for RID, even after reduction of the IgM. Reference and test sera should not differ too widely in IgM levels. The interaction between charged agar and human IgM explains the subgroup phenomenon described earlier by Klein et al. (1973).

Selenium status and chronic disease mortality: Dutch epidemiological findings.

This paper summarizes Dutch epidemiological findings on the impact of a low selenium (Se) status on mortality from cardiovascular disease (CVD) and cancer. Se status parameters of Dutch subjects are compared to those from Finland and the USA, and the concept of a threshold effect for Se on disease risk is discussed. Case-control analyses of prospective data suggest that low serum Se (below 105 micrograms/l) is not clearly associated with an excess risk of CVD death (relative risk RR = 1.6, 90% confidence interval Cl = 0.9-2.9). Se cancer findings indicate a possible gender difference in risk (in males RR = 2.7, 90% Cl = 1.2-6.2; in females RR = 1.5, 90% Cl = 0.5-4.5). Larger studies, monitoring a combination of Se status parameters are recommended.

Neuroimmune alterations in the complex regional pain syndrome.

This review focuses on some clinical aspects of the complex regional pain syndrome, such as oedema, local temperature changes and chronic pain, as a result of supposed neurogenic inflammation. Involvement of the immune system could imply the subsequent release of neuropeptides, pro-inflammatory cytokines and eicosanoids, which in turn leads to a complex cross-talk of primary and secondary generated mediators of inflammation. The development and application of drugs that act through selective receptor antagonism or enzymatic synthesis inhibition to prevent further stimulation of this cascade that could inevitably lead to chronicity of this disease are extensively discussed.