336 research outputs found
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Gene expression in human brain implicates sexually dimorphic pathways in autism spectrum disorders.
Autism spectrum disorder (ASD) is more prevalent in males, and the mechanisms behind this sex-differential risk are not fully understood. Two competing, but not mutually exclusive, hypotheses are that ASD risk genes are sex-differentially regulated, or alternatively, that they interact with characteristic sexually dimorphic pathways. Here we characterized sexually dimorphic gene expression in multiple data sets from neurotypical adult and prenatal human neocortical tissue, and evaluated ASD risk genes for evidence of sex-biased expression. We find no evidence for systematic sex-differential expression of ASD risk genes. Instead, we observe that genes expressed at higher levels in males are significantly enriched for genes upregulated in post-mortem autistic brain, including astrocyte and microglia markers. This suggests that it is not sex-differential regulation of ASD risk genes, but rather naturally occurring sexually dimorphic processes, potentially including neuron-glial interactions, that modulate the impact of risk variants and contribute to the sex-skewed prevalence of ASD
Solubility of precursors and carbonation of waterglass-free geopolymers
Geopolymers have the potential to function as an environmentally friendly substitute for ordinary Portland cement, with up to 80% less CO emission during production. The effect is best utilized for geopolymers prepared with amorphous silica instead of waterglass (NaSiO) to adjust the Si:Al ratio. The reactivity of the precursors with the alkaline activator affects the final mineralogical properties of the binder. The purpose of the present study was to investigate the amount of different phases formed during geopolymerization and to understand the quantitative evolution of carbonation during geopolymer synthesis by determining the solubility of metakaolinite and amorphous SiO in NaOH at various concentrations. The solubility was studied by ICP-OES measurements. X-ray diffraction was used for qualitative and quantitative phase analysis of the geopolymers. The solubility of the precursors increased with calcination temperature of metakaolinite, reaction time for amorphous SiO, and at higher NaOH concentrations. Partial dissolution resulted in free Na, which is a source for the formation of carbonates in the geopolymers. Thermonatrite occurred prior to trona formation in all samples
Macrophage Sub-Populations and the Lipoxin A4 Receptor Implicate Active Inflammation during Equine Tendon Repair
Macrophages (Mϕ) orchestrate inflammatory and reparatory processes in injured connective tissues but their role during different phases of tendon healing is not known. We investigated the contribution of different Mϕ subsets in an equine model of naturally occurring tendon injury. Post mortem tissues were harvested from normal (uninjured), sub-acute (3–6 weeks post injury) and chronically injured (>3 months post injury) superficial digital flexor tendons. To determine if inflammation was present in injured tendons, Mϕ sub-populations were quantified based on surface antigen expression of CD172a (pan Mϕ), CD14highCD206low (pro-inflammatory M1Mϕ), and CD206high (anti-inflammatory M2Mϕ) to assess potential polarised phenotypes. In addition, the Lipoxin A4 receptor (FPR2/ALX) was used as marker for resolving inflammation. Normal tendons were negative for both Mϕ and FPR2/ALX. In contrast, M1Mϕ predominated in sub-acute injury, whereas a potential phenotype-switch to M2Mϕ polarity was seen in chronic injury. Furthermore, FPR2/ALX expression by tenocytes was significantly upregulated in sub-acute but not chronic injury. Expression of the FPR2/ALX ligand Annexin A1 was also significantly increased in sub-acute and chronic injuries in contrast to low level expression in normal tendons. The combination of reduced FPR2/ALX expression and persistence of the M2Mϕ phenotype in chronic injury suggests a potential mechanism for incomplete resolution of inflammation after tendon injury. To investigate the effect of pro-inflammatory mediators on lipoxin A4 (LXA4) production and FPR2/ALX expression in vitro, normal tendon explants were stimulated with interleukin-1 beta and prostaglandin E2. Stimulation with either mediator induced LXA4 release and maximal upregulation of FPR2/ALX expression after 72 hours. Taken together, our data suggests that although tenocytes are capable of mounting a protective mechanism to counteract inflammatory stimuli, this appears to be of insufficient duration and magnitude in natural tendon injury, which may potentiate chronic inflammation and fibrotic repair, as indicated by the presence of M2Mϕ
High‐speed photoconductivity and infrared to visible up‐conversion in GaP light‐emitting diodes
In GaP:N (Zn,Te) light‐emitting diodes extrinsic photoconductivity and infrared to visible up‐conversion have been investigated by short laser pulses at 10‐μm wavelength. A time constant of the order of 1 ns was observed indicating that free infrared excited hole to bound donor recombination yields the fast response
The bovine chemokine receptors and their mRNA abundance in mononuclear phagocytes
<p>Abstract</p> <p>Background</p> <p>The chemokine and chemokine receptor families play critical roles in both the healthy and diseased organism mediating the migration of cells. The chemokine system is complex in that multiple chemokines can bind to one chemokine receptor and <it>vice versa</it>. Although chemokine receptors have been well characterised in humans, the chemokine receptor repertoire of cattle is not well characterised and many sequences are yet to be experimentally validated.</p> <p>Results</p> <p>We have identified and sequenced bovine homologs to all identified functional human chemokine receptors. The bovine chemokine receptors show high levels of similarity to their human counterparts and similar genome arrangements. We have also characterised an additional bovine chemokine receptor, not present in the available genome sequence of humans or the more closely related pigs or horses. This receptor shows the highest level of similarity to CCR1 but shows significant differences in regions of the protein that are likely to be involved in ligand binding and signalling. We have also examined the mRNA abundance levels of all identified bovine chemokine receptors in mononuclear phagocytic cells. Considerable differences were observed in the mRNA abundance levels of the receptors, and interestingly the identified novel chemokine receptor showed differing levels of mRNA abundance to its closest homolog CCR1. The chemokine receptor repertoire was shown to differ between monocytes, macrophages and dendritic cells. This may reflect the differing roles of these cells in the immune response and may have functional consequences for the trafficking of these cells <it>in vivo</it>.</p> <p>Conclusions</p> <p>In summary, we have provided the first characterisation of the complete bovine chemokine receptor gene repertoire including a gene that is potentially unique to cattle. Further study of this receptor and its ligands may reveal a specific role of this receptor in cattle. The availability of the bovine chemokine receptor sequences will allow further characterisation of the function of these genes and will confer wide-reaching benefits to the study of this important aspect of the bovine immune response.</p
Problematic use of the internet during the COVID-19 pandemic: Good practices and mental health recommendations.
With the onset of the COVID-19 pandemic and the accelerated spread of the SARS-CoV-2 virus came jurisdictional limitations on mobility of citizens and distinct alterations in their daily routines. Confined to their homes, many people increased their overall internet use, with problematic use of the internet (PUI) becoming a potential reason for increased mental health concerns. Our narrative review summarizes information on the extent of PUI during the pandemic, by focusing on three types: online gaming, gambling and pornography viewing. We conclude by providing guidance for mental health professionals and those affected by PUI (with an outline of immediate research priorities and best therapeutic approaches), as well as for the general public (with an overview of safe and preventative practices)
High‐speed photoconductivity and infrared to visible up‐conversion in GaP light‐emitting diodes
Mammalian lectin arrays for screening host-microbe interactions
Many members of the C-type lectin family of glycan-binding receptors have been ascribed roles in the recognition of microorganisms and serve as key receptors in the innate immune response to pathogens. Other mammalian receptors have become targets through which pathogens enter target cells. These receptor roles have often been documented with binding studies involving individual pairs of receptors and micro-organisms. To provide a systematic overview of interactions between microbes and the large complement of C-type lectins, here we developed a lectin array and suitable protocols for labeling of microbes that could be used to probe this array. The array contains C-type lectins from cow, chosen as a model organism of agricultural interest for which the relevant pathogen–receptor interactions have not been previously investigated in detail. Screening with yeast cells and various strains of both Gram-positive and -negative bacteria revealed distinct binding patterns, which in some cases could be explained by binding to lipopolysaccharides or capsular polysaccharides, but in other cases suggested the presence of novel glycan targets on many of the microorganisms. These results are consistent with interactions previously ascribed to the receptors, but also highlight binding to additional sugar targets that have not previously been recognized. Our findings indicate that mammalian lectin arrays represent unique discovery tools for identifying both novel ligands and new receptor functions
Probing host pathogen cross-talk by transcriptional profiling of both Mycobacterium tuberculosis and infected human dendritic cells and macrophages
This study provides the proof of principle that probing the host and the microbe transcriptomes simultaneously is a valuable means to accessing unique information on host pathogen interactions. Our results also underline the extraordinary plasticity of host cell and pathogen responses to infection, and provide a solid framework to further understand the complex mechanisms involved in immunity to M. tuberculosis and in mycobacterial adaptation to different intracellular environments
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