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In three-dimensional light microscopy, the heterogeneity of the optical density in a specimen ultimately limits the achievable penetration depth and hence the three-dimensional resolution. The most direct approach to reduce aberrations, improve the contrast and achieve an optimal resolution is to minimise the impact of changes of the refractive index along an optical path. Many implementations of light sheet fluorescence microscopy operate with a large chamber filled with an aqueous immersion medium and a further inner container with the specimen embedded in a possibly entirely different non-aqueous medium. In order to minimise the impact of the latter on the optical quality of the images, we use multi-facetted cuvettes fabricated from vacuum-formed ultra-thin fluorocarbon (FEP) foils. The ultra-thin FEP-foil cuvettes have a wall thickness of about 10–12 µm. They are impermeable to liquids, but not to gases, inert, durable, mechanically stable and flexible. Importantly, the usually fragile specimen can remain in the same cuvette from seeding to fixation, clearing and observation, without the need to remove or remount it during any of these steps. We confirm the improved imaging performance of ultra-thin FEP-foil cuvettes with excellent quality images of whole organs such us mouse oocytes, of thick tissue sections from mouse brain and kidney as well as of dense pancreas and liver organoid clusters. Our ultra-thin FEP-foil cuvettes outperform many other sample-mounting techniques in terms of a full separation of the specimen from the immersion medium, compatibility with aqueous and organic clearing media, quick specimen mounting without hydrogel embedding and their applicability for multiple-view imaging and automated image segmentation. Additionally, we show that ultra-thin FEP foil cuvettes are suitable for seeding and growing organoids over a time period of at least ten days. The new cuvettes allow the fixation and staining of specimens inside the holder, preserving the delicate morphology of e.g. fragile, mono-layered three-dimensional organoids.
Background: Organoids are morphologically heterogeneous three-dimensional cell culture systems and serve as an ideal model for understanding the principles of collective cell behaviour in mammalian organs during development, homeostasis, regeneration, and pathogenesis. To investigate the underlying cell organisation principles of organoids, we imaged hundreds of pancreas and cholangiocarcinoma organoids in parallel using light sheet and bright-field microscopy for up to 7 days.
Results: We quantified organoid behaviour at single-cell (microscale), individual-organoid (mesoscale), and entire-culture (macroscale) levels. At single-cell resolution, we monitored formation, monolayer polarisation, and degeneration and identified diverse behaviours, including lumen expansion and decline (size oscillation), migration, rotation, and multi-organoid fusion. Detailed individual organoid quantifications lead to a mechanical 3D agent-based model. A derived scaling law and simulations support the hypotheses that size oscillations depend on organoid properties and cell division dynamics, which is confirmed by bright-field microscopy analysis of entire cultures.
Conclusion: Our multiscale analysis provides a systematic picture of the diversity of cell organisation in organoids by identifying and quantifying the core regulatory principles of organoid morphogenesis.
Background: Age and preoperative anaemia are risk factors for poor surgical outcome and blood transfusion. The aim of this study was to examine the effect of iron supplementation in iron-deficient (ID) elderly patients undergoing major surgery.
Method: In this single-centre observational study, patients ≥ 65 years undergoing major surgery were screened for anaemia and ID. Patients were assigned to the following groups: A− (no anaemia); A−,ID+,T+ (no anaemia, iron-deficient, intravenous iron supplementation); A+ (anaemia); and A+,ID+,T+ (anaemia, iron-deficient, intravenous iron supplementation).
Results: Of 4,381 patients screened at the anaemia walk-in clinic, 2,381 (54%) patients were ≥ 65 years old and 2,191 cases were included in analysis. The ID prevalence was 63% in patients with haemoglobin (Hb) < 8 g/dl, 47.2% in patients with Hb from 8.0 to 8.9 g/dl, and 44.3% in patients with Hb from 9 to 9.9 g/dl. In severely anaemic patients, an Hb increase of 0.6 (0.4; 1.2) and 1.2 (0.7; 1.6) g/dl was detected with iron supplementation 6–10 and > 10 days before surgery, respectively. Hb increased by 0 (-0.1; 0) g/dl with iron supplementation 1–5 days before surgery, 0.2 (-0.1; 0.5) g/dl with iron supplementation 6–10 days before surgery, and 0.2 (-0.2; 1.1) g/dl with supplementation > 10 days before surgery (p < 0.001 for 1–5 vs. 6–10 days). Overall, 58% of A+,ID+,T+ patients showed an Hb increase of > 0.5 g/dl. The number of transfused red blood cell units was significantly lower in patients supplemented with iron (0 (0; 3)) compared to non-treated anaemic patients (1 (0; 4)) (p = 0.03). Patients with iron supplementation > 6 days before surgery achieved mobility 2 days earlier than patients with iron supplementation < 6 days.
Conclusions: Intravenous iron supplementation increases Hb level and thereby reduces blood transfusion rate in elderly surgical patients with ID anaemia.