A Multifunctional Nanostructured Hydrogel as a Platform for Deciphering Niche Interactions of Hematopoietic Stem and Progenitor Cells.

For over half a century, hematopoietic stem cells (HSCs) have been used for transplantation therapy to treat severe hematologic diseases. Successful outcomes depend on collecting sufficient donor HSCs as well as ensuring efficient engraftment. These processes are influenced by dynamic interactions of HSCs with the bone marrow niche, which can be revealed by artificial niche models. Here, a multifunctional nanostructured hydrogel is presented as a 2D platform to investigate how the interdependencies of cytokine binding and nanopatterned adhesive ligands influence the behavior of human hematopoietic stem and progenitor cells (HSPCs). The results indicate that the degree of HSPC polarization and motility, observed when cultured on gels presenting the chemokine SDF-1α and a nanoscale-defined density of a cellular (IDSP) or extracellular matrix (LDV) α4ß1 integrin binding motif, are differently influenced on hydrogels functionalized with the different ligand types. Further, SDF-1α promotes cell polarization but not motility. Strikingly, the degree of differentiation correlates negatively with the nanoparticle spacing, which determines ligand density, but only for the cellular-derived IDSP motif. This mechanism potentially offers a means of predictably regulating early HSC fate decisions. Consequently, the innovative multifunctional hydrogel holds promise for deciphering dynamic HSPC-niche interactions and refining transplantation therapy protocols.

A Digital Asset Inheritance Model to Convey Online Persona Posthumously.

The astounding growth of the Internet has generated digital asset extensively. Users are concerned about asset management so that the asset can be conveyed successfully to the descendent posthumously. Very few works have addressed designing and modeling of digital asset inheritance (DAI) from a technical design perspective. They have several inherent limitations such as incorrect death confirmation, high participation of nominee, the possibility of failure to obtain recovery key, and are based on many unreasonable assumptions, thus inefficient to design in the real life. In this paper, we have formalized the different categories of digital assets and defined the various security goals, required functionalities, and necessary entities to build an asset inheritance model. We have also proposed a new protocol named digital asset inheritance protocol (DAIP) using certificateless encryption (CLE) and identity-based system (IBS) to convey the user's online persona efficiently to the descendent after his death. DAIP allows the nominee to successfully retrieve the asset after the user's demise, even if a nominee is uninformed regarding the asset. We, then, provide rigorous security proofs of various properties using real-ideal worlds paradigm. Finally, we have implemented DAIP model using PBC and pycryptodome library. The simulation results affirm that it can be practically efficient to implement.

Safety, effectiveness and sustainability of a laboratory intervention to de-adopt culture of midstream urine samples among hospitalized patients.

OBJECTIVE: To assess the safety, sustainability, and effectiveness of a laboratory intervention to reduce processing of midstream urine (MSU) cultures. DESIGN: Prospective observational cohort. SETTING: Medical and surgical inpatients in a tertiary-care hospital. PARTICIPANTS: The study included 1,678 adult inpatients with an order for MSU culture. METHODS: From 2013 to 2019, ordered MSU cultures were not processed unless the laboratory was called. Patients were interviewed on days 0 and 4; from 2017 to 2019, day-30 follow-up was added. Primary outcome was serious adverse events due to not processing MSU cultures. Secondary outcomes were nonserious adverse events due to not processing MSU cultures, rates of MSU cultures submitted, proportion of MSU cultures processed, proportion of patients prescribed urinary tract infection (UTI)-directed antibiotics, and laboratory workload. RESULTS: Among 912 and 459 patients followed to days 4 and 30, respectively, no serious adverse events attributable to not processing MSU cultures were identified. However, 6 patients (0.66%) had prolonged urinary symptoms potentially associated with not processing MSU cultures. We estimated that 4 patients missed having empiric antibiotics stopped in response to negative MSU cultures, and 99 antibiotic courses for asymptomatic bacteriuria (ASB) and 8 antibiotic-associated adverse events were avoided. The rate of submitted MSU samples and proportion of patients receiving empiric UTI-directed antibiotics did not change. The proportion of MSU cultures processed declined from 59% to 49% (P < .0001), and total laboratory workload was reduced by 185 hours. CONCLUSIONS: De-adopting the processing of MSU cultures from medical and surgical inpatient units is safe and sustainable, and it reduces antibiotic prescriptions for ASB at a cost of prolonged urinary symptoms in a small proportion of patients.

Canalicular domain structure and function in matrix-free hepatic spheroids.

Liver is pivotal in organism metabolism. This organ is receiving nutriments from the portal vein and then storing, metabolizing, distributing in the circulation or excreting excess and xenobiotics in bile. Liver architecture and hepatocyte polarization are crucial to achieve these functions. To study these mechanisms in details, relevant cell culture systems are required, which is not the case with standard 2D cell culture. Besides, primary hepatocytes rapidly de-differenciate making them inefficient in forming physiological system. Herein, we used an hepatoma-derived cell line to produce matrix-free hepatic spheroids and developed an integrated structural cell biology methodology by combining light sheet fluorescence microscopy and 3D electron microscopy to study their function and structure. Within these spheroids, hepatocytes polarize and organize to form bile canaliculi active for both organics and inorganics excretion. Besides, live imaging revealed the high dynamic of actin networks in basal membranes compared to their high stability in the apical pole that constitutes bile canaliculi. Finally, the first structure of active bile canaliculi was solved at nm resolution and showed the very high density of microvilli coming from all cells constituting the canaliculus. Therefore, this study is the first comprehensive and in-depth functional and structural study of bile canaliculi in a physiological-relevant context.