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Expanded polytetrafluoroethylene (ePTFE), also known as Gore-Tex, is widely used as an implantable biomaterial in biomedical applications because of its favorable mechanical properties and biochemical inertness. However, infection and inflammation are two major complications with ePTFE implantations, because pathogenic bacteria can inhabit the microsized pores, without clearance by host immune cells, and the limited biocompatibility can induce foreign body reactions. To minimize these complications, we covalently grafted a biomembrane-mimic polymer, poly(2-methacryloyloxylethyl phosphorylcholine) (PMPC), by partial defluorination followed by UV-induced polymerization with cross-linkers on the ePTFE surface. PMPC grafting greatly reduced serum protein adsorption as well as fibroblast adhesion on the ePTFE surface. Moreover, the PMPC-grafted ePTFE surface exhibited a dramatic inhibition of the adhesion and growth of Staphylococcus aureus, a typical pathogenic bacterium in ePTFE implants, in the porous network. On the basis of an analysis of immune cells and inflammation-related factors, i.e., transforming growth factor-β (TGF-β) and myeloperoxidase (MPO), we confirmed that inflammation was efficiently alleviated in tissues around PMPC-grafted ePTFE plates implanted in the backs of rats. Covalent PMPC may be an effective strategy for promoting anti-inflammatory and antibacterial functions in ePTFE implants and to reduce side effects in biomedical applications of ePTFE.

Aggregatibacter actinomycetemcomitans lipopolysaccharide (Aa.LPS) is a major virulence factor associated with aggressive periodontitis. Although the recognition of Aa.LPS is potentially initiated by salivary proteins in the oral cavity, Aa.LPS-binding proteins (Aa.LPS-BPs) in saliva are poorly characterized. The purpose of this study was to capture and identify Aa.LPS-BPs in human saliva using a LTQ-Orbitrap hybrid Fourier transform mass spectrometry. Aa.LPS conjugated onto N-hydroxysuccinimidyl-Sepharose(®) 4 Fast Flow beads (Aa.LPS-beads) activated Toll-like receptor 4 and produced nitric oxide and Interferon gamma-inducible protein-10, implying that the conjugation process did not alter the biological properties of Aa.LPS. Aa.LPS-BPs were subsequently isolated from the nine human saliva samples from healthy individuals with the Aa.LPS-beads followed by identification with the mass spectrometry. Aa.LPS-BPs include α-amylase, serum albumin, cystatin, lysozyme C, submaxillary gland androgen-regulated protein 3B, immunoglobulin subunits, polymeric immunoglobulin receptor, deleted in malignant brain tumors 1, prolactin-inducible protein, lipocalin-1, and basic salivary proline-rich protein 2. Specific binding was validated using a pull-down assay with α-amylase which was captured at the highest frequency. Alpha-amylase demonstrated to interfere with the adherence and biofilm formation of A. actinomycetemcomitans. Even heat-inactivated α-amylase showed the interference to the same extent. Conclusively, we identified unique Aa.LPS-BPs that provide useful information to understand bacterial pathogenesis and host innate immunity in the oral cavity.

Background To classify waist circumference (WC) trajectories and examine each trajectory’s association with risk of incident type 2 diabetes mellitus (T2DM). Methods In Korean Genome and Epidemiology Study (KoGES 2001–2014), 4992 participants aged 40 years and above who received biennial health examinations from wave 1 to wave 4 (2001–2008) were selected. Five distinct trajectory groups were identified for WC using group-based trajectory modeling methods such as censored normal model. Cox proportional hazards model was used to examine the association of trajectories with risk of T2DM. Results During 31,118 person-years of follow-up (mean follow-up duration, 6.2 years), 276 incident cases of T2DM were identified. Through trajectory analysis, 5 distinct WC patterns were found during wave1 to wave 4, which were “Group A” was stable on very low levels, “Group B” was stable on low levels, “Group C” was stable on moderate levels, “Group D” had increasing pattern on elevated levels, “Group E” was shown increasing on high levels. Age-standardized incidences rates per 100,000 person-years were increased with WC expanding trajectory group (193.9 for Group A, 498.4 for Group B, 661.9 for Group C, 1845.9 for Group D, and 2045.0 for Group E). In multivariate analysis after adjusting for confounding variable at wave 4, Group B (Hazard ratio (HR), 2.2; 95% confidence interval (CI), and 1.1–4.6), Group C (HR: 2.5, 95% CI: 1.2–5.0), Group D (HR: 5.4, 95% CI: 2.7–10.9), Group E (HR: 7.3, 95% CI: 3.5–15.4) had a higher risk of T2DM than Group A. After further adjusting for body mass index strongly correlated with WC, the association was attenuated. Conclusions WC trajectory was a significant predictor of T2DM risk in increasing trajectories on high level. This finding indicate the importance of WC management across prolong lifespan by assessing the prognosis and prevention strategies of high-risk populations for T2DM in middle-aged adults. Electronic supplementary material The online version of this article (10.1186/s12889-019-7077-6) contains supplementary material, which is available to authorized users.

This study investigated the association between depressive symptoms and cognitive function according to four different trajectories of depressive symptoms in the late middle-aged and older South Korean population. Panel data from the Korean Longitudinal Study of Ageing were analyzed. We used latent class trajectory models to identify four trajectories of depressive symptoms. We performed linear mixed-effects regression analysis to assess associations between depressive-symptom trajectories and MMSE scores. Of 4,374 participants, 18.4%, 4.9%, 55.2%, and 21.5% were classified as having a low, increasing, moderate declining, and high depressive-symptom trajectory, respectively. Individuals with an increasing trajectory (β = −0.729, P ≤ 0.001), moderate trajectory (β = −0.278, P = 0.003), and high trajectory (β = −1.605, P ≤ 0.001) had lower MMSE scores compared with those in the low trajectory group. These relationships were particularly strong among women; individuals who were physically inactive; those who were separated, divorced, or single; and those with hypertension or cerebrovascular disease. Each trajectory group for depressive symptoms was associated with cognitive decline. Moreover, female, physically inactive, and single individuals, as well as those with hypertension and cerebrovascular disease should be particularly mindful of their mental and physical health to prevent cognitive decline.

The Markov modulated fluid model with finite buffer of size β is analyzed using a stochastic discretization yielding a sequence of finite waiting room queueing models with iid amounts of work distributed as exp(nλ). The n-th approximating queue's system size is bounded at a value q n such that the corresponding expected amount of work q n /(nλ) → β as n → ∞. We demonstrate that as n → ∞, we obtain the exact performance results for the finite buffer fluid model from the processes of work in the system for these queues. The necessary (strong) limit theorems are proven for both transient and steady state results. Algorithms for steady state results are developed fully and illustrated with numerical examples.