Comparison of Optical Coherence Tomography Measurement Reproducibility between Children and Adults

Purpose

To compare the reproducibility of SD-OCT (spectral-domain optical coherence tomography) measurements of RNFL (retinal nerve fiber layer) and macular thickness between children and adults.

Methods

Seventy-one eyes of 71 children and 71 eyes of 71 adults were prospectively enrolled. RNFL and macular thicknesses were measured by one operator, with a brief rest between measurements. The two measurements were obtained using the eye tracking and retest function of Spectralis SD-OCT. Reproducibility was evaluated with reference to COVs (coefficients of variation) and ICCs (intraclass correlation coefficients). The ICC values of the RNFL and macular thicknesses were compared, respectively between the two groups, by Fisher’s z-test.

Results

The RNFL and macular thicknesses did not differ between the two groups. The COVs of the RNFL measurements ranged from 0.945 to 4.531% in the children group and from 0.496 to 1.391% in the adults group. In most of the RNFL sectors, the ICCs of the children group (range: 0.731–0.987) were significantly lower than those of the adults group (range: 0.986–0.993). The COVs of the macular measurements ranged from 0.496 to 1.157% in the children group and from 0.275 to 0.656% in the adults group. The ICCs (range: 0.860–0.974) in the children group, significantly lower than for the adults (range: 0.989–0.995), in all of the macular sectors.

Conclusions

The reproducibility of SD-OCT RNFL and macular measurements for children was excellent, albeit statistically lower than that for adults.     

Orthotopic Hind Limb Transplantation in the Mouse

In vivo animal model systems, and in particular mouse models, have evolved into powerful and versatile scientific tools indispensable to basic and translational research in the field of transplantation medicine. A vast array of reagents is available exclusively in this setting, including mono- and polyclonal antibodies for both diagnostic and interventional applications. In addition, a vast number of genotyped, inbred, transgenic, and knock out strains allow detailed investigation of the individual contributions of humoral and cellular components to the complex interplay of an immune response and make the mouse the gold standard for immunological research. Vascularized Composite Allotransplantation (VCA) delineates a novel field of transplantation using allografts to replace "like with like" in patients suffering traumatic or congenital tissue loss. This surgical methodological protocol shows the use of a non-suture cuff technique for super-microvascular anastomosis in an orthotopic mouse hind limb transplantation model. The model specifically allows for comparison between established paradigms in solid organ transplantation with a novel form of transplants consisting of various different tissue components. Uniquely, this model allows for the transplantation of a viable vascularized bone marrow compartment and niche that have the potential to exert a beneficial effect on the balance of immune acceptance and rejection. This technique provides a tool to investigate alloantigen recognition and allograft rejection and acceptance, as well as enables the pursuit of functional nerve regeneration studies to further advance this novel field of transplantation.     

Emerging power of proteomics for delineation of intrinsic tumor subtypes and resistance mechanisms to anti-cancer therapies

Introduction: Despite extreme genetic heterogeneity, tumors often show similar alterations in the expression, stability, and activation of proteins important in oncogenic signaling pathways. Thus, classifying tumor samples according to shared proteomic features may help facilitate the identification of cancer subtypes predictive of therapeutic responses and prognostic for patient outcomes. Meanwhile, understanding mechanisms of intrinsic and acquired resistance to anti-cancer therapies at the protein level may prove crucial to devising reversal strategies.

Areas covered: Herein, we review recent advances in quantitative proteomic technology and their applications in studies to identify intrinsic tumor subtypes of various tumors, to illuminate mechanistic aspects of pharmacological and oncogenic adaptations, and to highlight interaction targets for anti-cancer compounds and cancer-addicted proteins.

Expert commentary: Quantitative proteomic technologies are being successfully employed to classify tumor samples into distinct intrinsic subtypes, to improve existing DNA/RNA based classification methods, and to evaluate the activation status of key signaling pathways.     

Circulating serum vitamin D levels and total body bone mineral density: A Mendelian randomization study

Until recently, randomized controlled trials have not demonstrated convincing evidence that vitamin D, or vitamin D in combination with calcium supplementation could improve bone mineral density (BMD), osteoporosis and fracture. It remains unclear whether vitamin D levels are causally associated with total body BMD. Here, we performed a Mendelian randomization study to investigate the association of vitamin D levels with total body BMD using a large‐scale vitamin D genome‐wide association study (GWAS) dataset (including 79 366 individuals) and a large‐scale total body BMD GWAS dataset (including 66,628 individuals). We selected three Mendelian randomization methods including inverse‐variance weighted meta‐analysis (IVW), weighted median regression and MR‐Egger regression. All these three methods did not show statistically significant association of genetically increased vitamin D levels with total body BMD. Importantly, our findings are consistent with recent randomized clinical trials and Mendelian randomization study. In summary, we provide genetic evidence that increased vitamin D levels could not improve BMD in the general population. Hence, vitamin D supplementation alone may not be associated with reduced fracture incidence among community‐dwelling adults without known vitamin D deficiency, osteoporosis, or prior fracture.     

Interferon‐gamma production in Lyme arthritis synovial tissue promotes differentiation of fibroblast‐like synoviocytes into immune effector cells

Lyme arthritis (LA), a late disease manifestation of Borrelia burgdorferi infection, usually resolves with antibiotic therapy. However, some patients develop proliferative synovitis lasting months to several years after spirochetal killing, called postinfectious LA. In this study, we phenotyped haematopoietic and stromal cell populations in the synovial lesion ex vivo and used these findings to generate an in vitro model of LA using patient‐derived fibroblast‐like synoviocytes (FLS). Ex vivo analysis of synovial tissue revealed high abundance of IFNγ‐producing T cells and NK cells. Similar to marked IFNγ responses in tissue, postinfectious LA synovial fluid also had high levels of IFNγ. HLA‐DR‐positive FLS were present throughout the synovial lesion, particularly in areas of inflammation. FLS stimulated in vitro with B. burgdorferi, which were similar to conditions during infection, expressed 68 genes associated primarily with innate immune activation and neutrophil recruitment. In contrast, FLS stimulated with IFNγ, which were similar to conditions in the postinfectious phase, expressed >2,000 genes associated with pathogen sensing, inflammation, and MHC Class II antigen presentation, similar to the expression profile in postinfectious synovial tissue. Furthermore, costimulation of FLS with B. burgdorferi and IFNγ induced greater expression of IL‐6 and other innate immune response proteins and genes than with IFNγ stimulation alone. These results suggest that B. burgdorferi infection, in combination with IFNγ, initiates the differentiation of FLS into a highly inflammatory phenotype. We hypothesise that overexpression of IFNγ by lymphocytes within synovia perpetuates these responses in the postinfectious period, causing proliferative synovitis and stalling appropriate repair of damaged tissue.     

Focal adhesion kinase is negatively regulated by phosphorylation at tyrosine 407

Focal adhesion kinase (FAK) mediates signal transduction in response to multiple extracellular inputs via tyrosine phosphorylation at specific residues. Although several tyrosine phosphorylation events have been linked to FAK activation and downstream signal transduction, the function of FAK phosphorylation at Tyr(407) was previously unknown. Here, we show for the first time that phosphorylation of FAK Tyr(407) increases during serum starvation, contact inhibition, and cell cycle arrest, all conditions under which activating FAK Tyr(397) phosphorylation decreases. Transfection of NIH3T3 cells with a phosphorylation-mimicking FAK 407E mutant decreased autophosphorylation at Tyr(397) and inhibited both FAK kinase activity in vitro and FAK-mediated functions such as cell adhesion, spreading, proliferation, and migration. The opposite effects were observed in cells transfected with nonphosphorylatable mutant FAK 407F. Taken together, these data suggest the novel concept that FAK Tyr(407) phosphorylation negatively regulates the enzymatic and biological activities of FAK.