Host and bacterial factors linking periodontitis and rheumatoid arthritis

Observations from numerous clinical, epidemiological and serological studies link periodontitis with severity and progression of rheumatoid arthritis. The strong association is observed despite totally different aetiology of these two diseases, periodontitis being driven by dysbiotic microbial flora on the tooth surface below the gum line, while rheumatoid arthritis being the autoimmune disease powered by anti-citrullinated protein antibodies (ACPAs). Here we discuss genetic and environmental risk factors underlying development of both diseases with special emphasis on bacteria implicated in pathogenicity of periodontitis. Individual periodontal pathogens and their virulence factors are argued as potentially contributing to putative causative link between periodontal infection and initiation of a chain of events leading to breakdown of immunotolerance and development of ACPAs. In this respect peptidylarginine deiminase, an enzyme unique among prokaryotes for Porphyromonas gingivalis, is elaborated as a potential mechanistic link between this major periodontal pathogen and initiation of rheumatoid arthritis development.

Clinics and genetic background of hereditary gingival fibromatosis

BACKGROUND

Hereditary gingival fibromatosis (HGF) is a rare condition characterized by slowly progressive overgrowth of the gingiva. The severity of overgrowth may differ from mild causing phonetic and masticatory issues, to severe resulting in diastemas or malposition of teeth. Both, autosomal-dominant and autosomal-recessive forms of HGF are described. The aim of this review is a clinical overview, as well as a summary and discussion of the involvement of candidate chromosomal regions, pathogenic variants of genes, and candidate genes in the pathogenesis of HGF. The loci related to non-syndromic HGF have been identified on chromosome 2 (GINGF, GINGF3), chromosome 5 (GINGF2), chromosome 11 (GINGF4), and 4 (GINGF5). Of these loci, pathogenic variants of the SOS-1 and REST genes inducing HGF have been identified in the GINGF and the GINGF5, respectively. Furthermore, among the top 10 clusters of genes ranked by enrichment score, ATP binding, and fibronectin encoding genes were proposed as related to HGF.

CONCLUSION

The analysis of clinical reports as well as translational genetic studies published since the late'90s indicate the clinical and genetic heterogeneity of non-syndromic HGF and point out the importance of genetic studies and bioinformatics of more numerous unrelated families to identify novel pathogenic variants potentially inducing HGF. This strategy will help to unravel the molecular  mechanisms as well as uncover specific targets for novel and less invasive therapies of this rare, orphan condition.

Mapping chromatin accessibility and active regulatory elements reveals pathological mechanisms in human gliomas

Chromatin structure and accessibility, and combinatorial binding of transcription factors to regulatory elements in genomic DNA control transcription. Genetic variations in genes encoding histones, epigenetics-related enzymes or modifiers affect chromatin structure/dynamics and result in alterations in gene expression contributing to cancer development or progression. Gliomas are brain tumors frequently associated with epigenetics-related gene deregulation. We perform whole-genome mapping of chromatin accessibility, histone modifications, DNA methylation patterns and transcriptome analysis simultaneously in multiple tumor samples to unravel epigenetic dysfunctions driving gliomagenesis. Based on the results of the integrative analysis of the acquired profiles, we create an atlas of active enhancers and promoters in benign and malignant gliomas. We explore these elements and intersect with Hi-C data to uncover molecular mechanisms instructing gene expression in gliomas.

Breakup of finite-size liquid filaments: Transition from no-breakup to breakup including substrate effects⋆

This work studies the breakup of finite-size liquid filaments, when also including substrate effects, using direct numerical simulations. The study focuses on the effects of three parameters: Ohnesorge number, the ratio of the viscous forces to inertial and surface tension forces, the liquid filament aspect ratio, and where there is a substrate, a measure of the fluid slip on the substrate, i.e. slip length. Through these parameters, it is determined whether a liquid filament breaks up during the evolution toward its final equilibrium state. Three scenarios are identified: a collapse into a single droplet, the breakup into one or multiple droplets, and recoalescence into a single droplet after the breakup (or even possibly another breakup after recoalescence). The results are compared with the ones available in the literature for free-standing liquid filaments. The findings show that the presence of the substrate promotes the breakup of the filament. The effect of the degree of slip on the breakup is also discussed. The parameter domain regions are comprehensively explored when including the slip effects. An experimental case is also carried out to illustrate the collapse and breakup of a finite-size silicon oil filament supported on a substrate, showcasing a critical length of the breakup in a physical configuration. Finally, direct numerical simulations reveal striking new details into the breakup pattern for low Ohnesorge numbers, where the dynamics are fast and the experimental imaging is not available; our results therefore significantly extend the range of Ohnesorge number over which filament breakup has been considered.

Giant visible and infrared light attenuation effect in nanostructured narrow-bandgap glasses

A unique effect of Bi on the optical and electrical properties of mixed Ga-containing Ge-Se and Ge-Te glasses is discovered. It is shown that glass with a low Bi content is completely transparent in a 3-16 μm spectral range, while the glass with a slightly higher Bi content possesses a large (>10  db/mm) attenuation coefficient, making a ∼millimeter thick glass sample fully opaque to VIS-IR radiation. Despite this contrast, both types of glass are found to retain their semiconducting properties, the DC conductivity at room temperature, σ_DC∼10^-3  S/m, being comparable to that of silicon.

Nanoscale Inhomogeneities Mapping in Ga-Modified Arsenic Selenide Glasses

Nanoscale inhomogeneities mapping in Ga-modified As₂Se₃ glass was utilized exploring possibilities of nanoindentation technique using a Berkovitch-type diamond tip. Structural inhomogeneities were detected in Ga_x(As_0.40Se_0.60)_100-x alloys with more than 3 at.% of Ga. The appeared Ga₂Se₃ nanocrystallites were visualized in Ga-modified arsenic selenide glasses using scanning and transmission electron microscopy. The Ga additions are shown to increase nanohardness and Young's modulus, this effect attaining an obvious bifurcation trend in crystallization-decomposed Ga₅(As_0.40Se_0.60)₉₅ alloy.

Free-Volume Nanostructurization in Ga-Modified As2Se3 Glass

Different stages of intrinsic nanostructurization related to evolution of free-volume voids, including phase separation, crystalline nuclei precipitation, and growth, were studied in glassy As2Se3 doped with Ga up to 5 at. %, using complementary techniques of positron annihilation lifetime spectroscopy, X-ray powder diffraction, and scanning electron microscopy with energy-dispersive X-ray analysis. Positron lifetime spectra reconstructed in terms of a two-state trapping model testified in favor of a native void structure of g-As2Se3 modified by Ga additions. Under small Ga content (below 3 at. %), the positron trapping in glassy alloys was dominated by voids associated with bond-free solid angles of bridging As2Se4/2 units. This void agglomeration trend was changed on fragmentation with further Ga doping due to crystalline Ga2Se3 nuclei precipitation and growth, these changes being activated by employing free volume from just attached As-rich glassy matrix with higher content of As2Se4/2 clusters. Respectively, the positron trapping on free-volume voids related to pyramidal AsSe3/2 units (like in parent As2Se3 glass) was in obvious preference in such glassy crystalline alloys.

[Use of filgrastim (RHU G-CSF) in supplemental treatment of non Hodgkin's lymphoma (NHL) in children]

Clinical application of glycoproteins stimulating the growth (G-CSF), differentiation and activity of the cells of granulocyte line has become a landmark in the treatment of patients with neutropenia. It has been proved that filgrastim (rHU G-CSF) applied after intensive chemotherapy shortens the duration of neutropenia and decreases the frequency of occurrence of infections. The paper discusses the efficiency and tolerance of filgrastim in children treated for NHL. Filgrastim was applied in children with NHL T cell and B cell treated according to BFM 86 protocols. It was given in a dose of 5 micrograms/kg daily i.v. The duration of therapy ranged from 5-20 days. Altogether 47 cycles were performed. 25 cycles were performed in 12 children during granulocytopenia (< 1 x 10(9)/l). The median time of neutropenia recovery, the frequency of severe infection and chemotherapy retardation were significantly lower in the examined than in the control group (p < 0.05). In 6 children 22 courses of filgrastim were given prophylactically after the cycles of intensive chemotherapy of NHL. Only during two courses due to neutropenia the chemotherapy retardation was necessary. Toleration of filgrastim was good. Application of filgrastim right after the intensive chemotherapy in children with NHL has considerably improved persistent realization of treatment programmes. Tolerance of the drug was good.