The Relation between Oral Candida Load and Bacterial Microbiome Profiles in Dutch Older Adults.

Currently there are no evidence-based ecological measures for prevention of overgrowth and subsequent infection by fungi in the oral cavity. The aim of this study was to increase our knowledge on fungal-bacterial ecological interactions. Salivary Candida abundance of 82 Dutch adults aged 58-80 years was established relative to the bacterial load by quantitative PCR analysis of the Internal Transcribed (ITS) region (Candida) and 16S rDNA gene (bacteria). The salivary microbiome was assessed using barcoded pyrosequencing of the bacterial hypervariable regions V5-V7 of 16S rDNA. Sequencing data was preprocessed by denoising and chimera removal, clustered in Operational Taxonomic Units (OTUs) and assigned to taxonomy. Both OTU-based (PCA, diversity statistics) and phylogeny-based analyses (UniFrac, PCoA) were performed. Saliva of Dutch older adults contained 0-4 × 108 CFU/mL Candida with a median Candida load of 0.06%. With increased Candida load the diversity of the salivary microbiome decreased significantly (p<0.001). Increase in the Candida load correlated positively with class Bacilli, and negatively with class Fusobacteria, Flavobacteria, and Bacteroidia. Microbiomes with high Candida load were less diverse and had a distinct microbial composition towards dominance by saccharolytic and acidogenic bacteria - streptococci. The control of the acidification of the oral environment may be a potential preventive measure for Candida outgrowth that should be evaluated in longitudinal clinical intervention trials. © 2012 Kraneveld et al

Differential Modulation by Akkermansia muciniphila and Faecalibacterium prausnitzii of Host Peripheral Lipid Metabolism and Histone Acetylation in Mouse Gut Organoids.

The gut microbiota is essential for numerous aspects of human health. However, the underlying mechanisms of many host-microbiota interactions remain unclear. The aim of this study was to characterize effects of the microbiota on host epithelium using a novel ex vivo model based on mouse ileal organoids. We have explored the transcriptional response of organoids upon exposure to short-chain fatty acids (SCFAs) and products generated by two abundant microbiota constituents, Akkermansia muciniphila and Faecalibacterium prausnitzii. We observed that A. muciniphila metabolites affect various transcription factors and genes involved in cellular lipid metabolism and growth, supporting previous in vivo findings. Contrastingly, F. prausnitzii products exerted only weak effects on host transcription. Additionally, A. muciniphila and its metabolite propionate modulated expression of Fiaf, Gpr43, histone deacetylases (HDACs), and peroxisome proliferator-activated receptor gamma (Ppar¿), important regulators of transcription factor regulation, cell cycle control, lipolysis, and satiety. This work illustrates that specific bacteria and their metabolites differentially modulate epithelial transcription in mouse organoids. We demonstrate that intestinal organoids provide a novel and powerful ex vivo model for host-microbiome interaction studies

Air versus fluorinated gas tamponades in pars plana vitrectomy treatment for primary rhegmatogenous retinal detachment

PURPOSE: To compare the treatment success of air with fluorinated gas (20% SF(6) or 14% C(3) F(8) ) tamponade in pars plana vitrectomy for primary rhegmatogenous retinal detachment. METHODS: A retrospective cohort study comprised of 1023 consecutive primary retinal detachment cases between 2014 and 2020. We employed a univariate multivariable binary logistic regression model. RESULTS: We used intraocular gas tamponades in 872 cases with PVR grade B or lower: air tamponade was used in 414 eyes and 458 eyes were treated with a type of fluorinated gas tamponade. There was no significant difference in the type of tamponade with regard to the re-detachment rate (95% CI -1.0% and 4.1%). Additionally, also in the subgroup of rhegmatogenous retinal detachments with inferior located retinal defects we found no significant difference between the two types of tamponade (p = 0.54 Fisher's exact). The multivariable model, which included tamponade, PVR grade, a retinal detachment involving the 6 o'clock position and age as covariates, also showed no significant effect of tamponade choice on treatment success (OR 0.5, 95% 0.2-1.0, p = 0.10). CONCLUSION: We found no difference in treatment success with air tamponade versus fluorinated gas tamponades in the repair of primary retinal detachments, this also includes inferiorly located retinal tears and detachments

Diffraction analysis of nonuniform stresses in surface layers:Application to cracked TiN coatings chemically vapor deposited on Mo

Variations of residual stresses in layers on substrates can occur in directions parallel and perpendicular to the surface as a result of compositional inhomogeneity and/or porosity or cracks. Diffraction methods to evaluate such stress variations are presented. Comparison of the experimental value for the stress with a calculated value of the “diffraction-averaged stress,” on the basis of a model for the local stresses, proved to be a useful method of stress analysis. It is shown that a direct evaluation of occurring stress-depth profiles is less practical. The method of stress analysis proposed, is applied to chemically vapor deposited TiN coatings on Mo substrates. In these coatings a large tensile stress parallel to the surface develops during cooling from the deposition temperature, due to difference in thermal shrink between coating and substrate. As a result of the cooling-induced stress, cracking of the coating occurs. The mesh width of the crack pattern allows determination of the fracture-surface energy and the fracture toughness of the coating material. Conceiving the cracked coatings as assemblies of freestanding columns, and assuming full elastic accommodation of the thermal mismatch at the column/substrate interface, the stress variations in the coating are calculated. On this basis the diffraction-averaged stress and the depth profile of the laterally averaged stress can be predicted accurately for the cracked TiN layers