A counter-rotating Couette apparatus to study deformation of a sub-millimeter sized particle in shear flow

We describe a new counter-rotating Couette apparatus that has been developed for deformation studies of single sub-millimeter sized particles in shear flow. New features are the adaption to the low viscosities of water-based systems and temperature control of the device. The inner to outer radius ratio of the cylinders used is 0.9785 and the height to width aspect ratio of the gap is 4.0, while the inner radius is 100 mm. Because of the limited particle size a high mechanical accuracy of the Couette geometry is necessary. The swing of the inner cylinder is less than 2 μm and that of the outer cylinder less than 4 μm. We achieved this by carefully choosing the design parameters of the aerostatic bearing and the coupling between cylinder and motor unit. Furthermore, special drive units give a shear rate resolution of 0.018 s−1, while the maximum shear rate is 100 s−1. For a liquid viscosity on the order of 1 mPas the effective maximum shear rate is 30 s−1. We have shown that deformations as small as (L−B)/(L+B) ≈ 0.01 of giant bilayer vesicles (typical radius 10 μm) with length L and width B can be observed with our device

Klimaat onderzoek bij het Nederlands Instituut voor Onderzoek der Zee

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Efficacy of pectins with different degrees of methyl-esterification and of blockiness in preventing gut epithelial cell barrier disruption and the impact on sodium-glucose co-transporter expression under low and high glucose conditions

Pectins support intestinal barrier function and have anti-diabetic effects, and can differ in the degree of methyl-esterification (DM) and the distribution of non-esterified galacturonic acid residues (DB). The mechanisms and effects of pectin type at different glucose levels are unknown. Pectins with different DM/DB on T84 cells were tested in the presence and absence of the barrier disruptor A23187 at 5 mM and 20 mM glucose. DM19 and DM43 pectins with high DB do rescue the intestinal barrier from disruption. Their effects were as strong as those of the barrier-rescuing anti-diabetic drug metformin, but effects with metformin were restricted to high glucose levels while pectins had effects at both low and high glucose levels. At high glucose levels, DM43HB pectin, which enhanced trans-epithelial electrical resistance, also increased the expressions of claudin1, occludin, and ZO-1. Low and high DM pectins decrease the apical expression of the sodium-glucose co-transporter (SGLT-1) and thereby influence glucose transport, explaining the anti-diabetogenic effect of pectin. Higher DB pectins had the strongest effect. Their impact on SGLT-1 was stronger than that of metformin. Pectin's rescuing effect on barrier disruption and its impact on glucose transportation and anti-diabetogenic effects depend on both the DB and the DM of pectins.</p

Intradermal Administration of Influenza Vaccine with Trehalose and Pullulan-Based Dissolving Microneedle Arrays

Most influenza vaccines are administered via intramuscular injection which has several disadvantages that might jeopardize the compliance of vaccinees. Intradermal administration of dissolving-microneedle-arrays (dMNAs) could serve as minimal invasive alternative to needle injections. However, during the production process of dMNAs antigens are subjected to several stresses, which may reduce their potency. Moreover, the needles need to have sufficient mechanical strength to penetrate the skin and subsequently dissolve effectively to release the incorporated antigen. Here, we investigated whether blends of trehalose and pullulan are suitable for the production of stable dMNA fulfilling these criteria. Our results demonstrate that production of trehalose/pullulan-based dMNAs rendered microneedles that were sharp and stiff enough to pierce into ex vivo human skin and subsequently dissolve within 15 min. The mechanical properties of the dMNAs were maintained well even after four weeks of storage at temperatures up to 37°C. In addition, immunization of mice with influenza antigens via both freshly prepared dMNAs and dMNAs after storage (four weeks at 4°C or 37°C) resulted in antibody titers of similar magnitude as found in intramuscularly injected mice and partially protected mice from influenza virus infection. Altogether, our results demonstrate the potential of trehalose/pullulan-based dMNAs as alternative dosage form for influenza vaccination.Drug Delivery Technolog

Radiation-Induced Myocardial Fibrosis in Long-Term Esophageal Cancer Survivors

Purpose: Radiation-induced cardiac toxicity is a potential lethal complication. The aim of this study was to assess whether there is a dose-dependent relationship between radiation dose and myocardial fibrosis in patients who received neoadjuvant chemoradiation (nCRT) for esophageal cancer (EC). Methods and Materials: Forty patients with EC treated with a transthoracic esophagectomy with (n = 20) or without (n = 20) nCRT (CROSS study regimen) were included. Cardiovascular magnetic resonance imaging (1.5 Tesla) for left ventricular (LV) function, late gadolinium enhancement, and T1 mapping were performed. Extracellular volume (ECV), as a surrogate for collagen burden, was measured for all LV segments separately. The dose-response relationship between ECV and mean radiation dose per LV myocardial segment was evaluated using a mixed-model analysis. Results: Seventeen nCRT and 16 control patients were suitable for analysis. The mean time after treatment was 67.6 +/- 8.1 (nCRT) and 122 +/- 35 (controls) months (P = .02). In nCRT patients, we found a significantly higher mean global ECV of 28.2% compared with 24.0% in the controls (P < .001). After nCRT, LV myocardial segments with elevated ECV had received significantly higher radiation doses. In addition, a linear dose-effect relation was found with a 0.136% point increase of ECV for each Gy (P < .001). There were no differences in LV function measures and late gadolinium enhancement between both groups. Conclusions: Myocardial ECV was significantly higher in long-term EC survivors after nCRT compared with surgery only. Moreover, this ECV increase was linear with the radiation dose per LV segment, indicating radiation-induced myocardial fibrosis. (C) 2021 The Author(s). Published by Elsevier Inc

Late cardiac toxicity of neo-adjuvant chemoradiation in esophageal cancer survivors:A prospective cross-sectional pilot study

Purpose: Although cure rates in esophageal cancer (EC) have improved since the introduction of neoadjuvant chemoradiation (nCRT), evidence for treatment-related cardiac toxicity is growing, of which the exact mechanisms remain unknown. The primary objective of this study was to identify (subclinical) cardiac dysfunction in EC patients after nCRT followed by surgical resection as compared to surgery alone. Materials and Methods: EC survivors followed for 5-15 years after curative resection with (n = 20) or without (n = 20) nCRT were enrolled in this prospective cross-sectional pilot study. All patients underwent several clinical and diagnostic tests in order to objectify (sub)clinical cardiac toxicity including cardiac CT and MRI, echocardiography, ECG, 6-minutes walking test, physical examination and EORTC questionnaires. Results: We found an increased rate of myocardial fibrosis (Linear late gadolinium enhancement (LGE) 4 vs. 1; p = 0.13; mean extracellular volume (ECV) 28.4 vs. 24.0; p < 0.01), atrial fibrillation (AF) (6 vs. 2; p = 0.07) and conduction changes in ECG among patients treated with nCRT as compared to those treated with surgery alone. The results suggested an impact on quality of life in terms of worse role functioning for this patient group (95.0 vs. 88.8; p = 0.03). Conclusion: Based on our analyses we hypothesize that in EC patients, radiation-induced myocardial fibrosis plays a central role in cardiac toxicity leading to AF, conduction changes and ultimately to decreased role functioning. The results emphasize the need to verify these findings in larger cohorts of patients. (C) 2021 The Author(s). Published by Elsevier B.V

Clinical selection strategy for and evaluation of intra-operative brachytherapy in patients with locally advanced and recurrent rectal cancer

Background and purpose: A radical resection of locally advanced rectal cancer (LARC) or recurrent rectal cancer (RRC) can be challenging. In case of increased risk of an R1 resection, intra-operative brachytherapy (IOBT) can be applied. We evaluated the clinical selection strategy for IOBT. Materials and methods: Between February 2007 and May 2018, 132 LARC/RRC patients who were scheduled for surgery with IOBT standby, were evaluated. By intra-operative inspection of the resection margin and MR imaging, it was determined whether a resection was presumed to be radical. Frozen sections were taken on indication. In case of a suspected R1 resection, IOBT (1 x 10 Gy) was applied. Histopathologic evaluation, treatment and toxicity data were collected from medical records. Results: Tumour was resected in 122 patients. IOBT was given in 42 patients of whom 54.8% (n = 23) had a histopathologically proven R1 resection. Of the 76 IOBT-omitted R0 resected patients, 17.1% (n = 13) had a histopathologically proven R1 resection. In 4 IOBT-omitted patients, a clinical R1/2 resection was seen. In total, correct clinical judgement occurred in 72.6% (n = 88) of patients. In LARC, 58.3% (n = 14) of patients were overtreated (R0, with IOBT) and 10.9% (n = 5) were undertreated (R1, without IOBT). In RRC, 26.5% (n = 9) of patients were undertreated. Conclusion: In total, correct clinical judgement occurred in 72.6% (n = 88). However, in 26.5% (n = 9) RRC patients, IOBT was unjustifiedly omitted. IOBT is accompanied by comparable and acceptable toxicity. Therefore, we recommend IOBT to all RRC patients at risk of an R1 resection as their salvage treatment. (c) 2021 The Author(s). Published by Elsevier B.V. Radiotherapy and Oncology 159 (2021) 91 & ndash;97 This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

The level and distribution of methyl-esters influence the impact of pectin on intestinal T cells, microbiota, and Ahr activation

Pectins are dietary fibres that modulate T cell immunity, microbiota composition, and fermentation profiles, but how this is influenced by the degree of methyl-esterification (DM) and degree-of-blockiness (DB) of pectin is unknown. Here, we demonstrate that supplementation of DM19(high-DB), DM49(low-DB) and DM43(high-DB) pectins at a low dose increased the frequencies of intestinal T-helper (Th)1 and Th2 cells after 1 week of pectin supplementation in mice, whereas DM18(low-DB) did not. After 4 weeks of supplementation with those pectins, Th1 and Th2 frequencies returned to control levels, whereas Rorγt+ regulatory T-cell frequencies increased. These structure-dependent effects could derive from induced shifts in microbiota composition that differed between DM18(low-DB) pectin and the other pectins. T-cell-modulating effects were not short-chain-fatty acid-dependent, but rather through an increase in Aryl-hydrocarbon-receptor-activating components. Thus, pectins with a specific combination of DM and DB have an impact on intestinal T cell-immunity in mice, when supplemented at a low dose