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There is an interesting and long history of prostheses designed for those with upper-limb difference, and yet issues still persist that have not yet been solved. Prosthesis needs for children are particularly complex, due in part to their growth rates. Access to a device can have a significant impact on a child’s psychosocial development. Often, devices supporting both cosmetic form and user function are not accessible to children due to high costs, insurance policies, medical availability, and their perceived durability and complexity of control. These challenges have encouraged a grassroots effort globally to offer a viable solution for the millions of people living with limb difference around the world. The innovative application of 3D printing for customizable and user-specific hardware has led to open-source Do It Yourself “DIY” production of assistive devices, having an incredible impact globally for families with little recourse. This paper examines new research and development of prostheses by the maker community and nonprofit organizations, as well as a novel case study exploring the development of technology and the training methods available. These design efforts are discussed further in the context of the medical regulatory framework in the United States and highlight new associated clinical studies designed to measure the quality of life impact of such devices.

An algorithm that allows rare cell type identification in a complex population of single cells, based on single-cell mRNA-sequencing, is applied to mouse intestinal cells, revealing novel subtypes of enteroendocrine cells and showing that the Lgr5-expressing population consists of a homogenous stem cell population with a few rare secretory cells, including Paneth cells. Rare cells stand out from the crowd Identifying and tracking rare cell types of physiological importance in a mixed population is a challenge. This study, a collaboration between the labs of Hans Clevers and Alexander van Oudenaarden, tackles the issue by applying single-cell mRNA sequencing to mouse intestinal organoids. The authors develop an algorithm, called RaceID, that allows rare cell type identification in a complex population of single cells. They define a marker for rare enteroendocrine cells of the intestine. Analysis of cells from a primary mouse intestine using this method, reveals that the Lgr5 -expressing population consists of a homogenous stem cell population with a few rare secretory cells, including Paneth cells. Understanding the development and function of an organ requires the characterization of all of its cell types. Traditional methods for visualizing and isolating subpopulations of cells are based on messenger RNA or protein expression of only a few known marker genes. The unequivocal identification of a specific marker gene, however, poses a major challenge, particularly if this cell type is rare. Identifying rare cell types, such as stem cells, short-lived progenitors, cancer stem cells, or circulating tumour cells, is crucial to acquire a better understanding of normal or diseased tissue biology. To address this challenge we first sequenced the transcriptome of hundreds of randomly selected cells from mouse intestinal organoids 1 , cultured self-organizing epithelial structures that contain all cell lineages of the mammalian intestine. Organoid buds, like intestinal crypts, harbour stem cells that continuously differentiate into a variety of cell types, occurring at widely different abundances 2 . Since available computational methods can only resolve more abundant cell types, we developed RaceID, an algorithm for rare cell type identification in complex populations of single cells. We demonstrate that this algorithm can resolve cell types represented by only a single cell in a population of randomly sampled organoid cells. We use this algorithm to identify Reg4 as a novel marker for enteroendocrine cells, a rare population of hormone-producing intestinal cells 3 . Next, we use Reg4 expression to enrich for these rare cells and investigate the heterogeneity within this population. RaceID confirmed the existence of known enteroendocrine lineages, and moreover discovered novel subtypes, which we subsequently validated in vivo . Having validated RaceID we then applied the algorithm to ex vivo -isolated Lgr5 -positive stem cells and their direct progeny. We find that Lgr5 -positive cells represent a homogenous abundant population of stem cells mixed with a rare population of Lgr5 -positive secretory cells. We envision broad applicability of our method for discovering rare cell types and the corresponding marker genes in healthy and diseased organs.

Haematopoietic stem cells (HSCs) are generated from haemogenic endothelial (HE) cells via the formation of intra-aortic haematopoietic clusters (IAHCs) in vertebrate embryos. The molecular events controlling endothelial specification, endothelial-to-haematopoietic transition (EHT) and IAHC formation, as it occurs in vivo inside the aorta, are still poorly understood. To gain insight in these processes, we performed single-cell RNA-sequencing of non-HE cells, HE cells, cells undergoing EHT, IAHC cells, and whole IAHCs isolated from mouse embryo aortas. Our analysis identified the genes and transcription factor networks activated during the endothelial-to-haematopoietic switch and IAHC cell maturation toward an HSC fate. Our study provides an unprecedented complete resource to study in depth HSC generation in vivo. It will pave the way for improving HSC production in vitro to address the growing need for tailor-made HSCs to treat patients with blood-related disorders. Haematopoietic stem cells (HSCs) are generated from haemogenic endothelial (HE) cells in vertebrate embryo aortas. Here, the authors perform single-cell RNA-sequencing of cells isolated from embryonic mouse aortas to identify genes and transcription factor networks activated during the endothelial-to-haematopoietic switch.

MDM2 is the principal antagonist of the tumor suppressor p53. p53 binds to its cognate DNA element within promoters and activates the transcription of adjacent genes. These target genes include MDM2. Upon induction by p53, the MDM2 protein binds and ubiquitinates p53, triggering its proteasomal degradation and providing negative feedback. This raises the question whether MDM2 can also remove p53 from its target promoters, and whether this also involves ubiquitination. In the present paper, we employ the MDM2-targeted small molecule Nutlin-3a (Nutlin) to disrupt the interaction of MDM2 and p53 in three different cancer cell lines: SJSA-1 (osteosarcoma), 93T449 (liposarcoma; both carrying amplified MDM2), and MCF7 (breast adenocarcinoma). Remarkably, removing Nutlin from the culture medium for less than five minutes not only triggered p53 ubiquitination, but also dissociated most p53 from its chromatin binding sites, as revealed by chromatin immunoprecipitation. This also resulted in reduced p53-responsive transcription, and it occurred much earlier than the degradation of p53 by the proteasome, arguing that MDM2 removes p53 from promoters prior to and thus independent of degradation. Accordingly, the short-term pharmacological inhibition of the proteasome did not alter the removal of p53 from promoters by Nutlin washout. However, when the proteasome inhibitor was applied for several hours, depleting non-conjugated ubiquitin prior to eliminating Nutlin, this compromised the removal of DNA-bound p53, as did an E1 ubiquitin ligase inhibitor. This suggests that the ubiquitination of p53 by MDM2 is necessary for its clearance from promoters. Depleting the MDM2 cofactor MDM4 in SJSA cells did not alter the velocity by that p53 was removed from promoters upon Nutlin washout. We conclude that MDM2 antagonizes p53 not only by covering its transactivation domain and by destabilization, but also by the rapid, ubiquitin-dependent termination of p53–chromatin interactions.

The Mdm4 (alias MdmX) oncoprotein, like its paralogue and interaction partner Mdm2, antagonizes the tumor suppressor p53. p53-independent roles of the Mdm proteins are emerging, and we have reported the ability of Mdm2 to modify chromatin and to support DNA replication by suppressing the formation of R-loops (DNA/RNA-hybrids). We show here that the depletion of Mdm4 in p53-deficient cells compromises DNA replication fork progression as well. Among various deletion mutants, only full-length Mdm4 was able to support DNA replication fork progression. Co-depletion of Mdm4 and Mdm2 further impaired DNA replication, and the overexpression of each partially compensated for the other’s loss. Despite impairing replication, Mdm4 depletion only marginally hindered cell proliferation, likely due to compensation through increased firing of replication origins. However, depleting Mdm4 sensitized p53−/− cells to the nucleoside analog gemcitabine, raising the future perspective of using Mdm4 inhibitors as chemosensitizers. Mechanistically, Mdm4 interacts with members of the Polycomb Repressor Complexes and supports the ubiquitination of H2A, thereby preventing the accumulation of DNA/RNA-hybrids. Thus, in analogy to previously reported activities of Mdm2, Mdm4 enables unperturbed DNA replication through the avoidance of R-loops.

Thanksgiving is a time for me to enjoy being with my family. Besides eating a fantastic dinner, we go shopping and watch football games. We also begin decorating our house for Christmas. I love the Thanksgiving holiday, because it gives my family time to relax together. Once school starts in August, the days pass very quicky, and November brings a welcome rest from the stress of school. The Thanksgiving holiday allows us to stop and enjoy the blessings of family. Thanksgiving is a very blithe time of year for people nationwide. This holiday is a time to express our thanks to God for everything we have and all he has done. Many people celebrate Thanksgiving by gathering with family and friends to eat lots of food. Families feast on the classic turkey, gravy, mashed potatoes and the traditional cranberry sauce. As the temperature falls, the common green leaves of summer change to the unique red and yellow leaves of autumn. Thanksgiving is definitely [a time] to thank God for all we are blessed with, including the beautiful world we live in. Thanksgiving is a wonderful time of year. You can express to those in your life how thankful you are to have them. You can thank God for everything that you have. All the while eating the classic turkey, gravy, mashed potatoes and, of course, pie. I love Thanksgiving because the weather is great outside and everyone is very cheerful. Thanksgiving is a time to pause, give prayers of thanks ... and then eat.

Patients with hypermobile Ehlers-Danlos syndrome (hEDS) frequently suffer from poor balance and proprioception and are at an increased risk for falls. Here we present a means of assessing a variety of balance and postural conditions in a fast and non-invasive manner. The equipment required is commercially available and requires limited personnel. Patients can be repeatedly tested to determine balance and postural differences as a result of disease progression and aging, or a reversal following balance/exercise interventions.

Refractory cancers may arise either through the acquisition of resistance mechanisms or represent distinct disease states. The origin of childhood T-cell acute lymphoblastic leukaemia (T-ALL) that does not respond to initial treatment, i.e. refractory disease, is unknown. Refractory T-ALL carries a poor prognosis and cannot be predicted at diagnosis. Here, we perform single cell mRNA sequencing of T-ALL from 58 children (84 samples) who did, or did not respond to initial treatment. We identify a transcriptionally distinctive blast population, exhibiting features of innate-like lymphocytes, as the major source of refractory disease. Evidence of such blasts at diagnosis heralds refractory disease across independent datasets and is associated with survival in a large, contemporary trial cohort. Our findings portray refractory T-ALL as a distinct disease with the potential for immediate clinical utility. T-cell acute lymphoblastic leukemia is a highly aggressive disease with varying recurrence rates. Here, the authors build a single cell transcriptomic atlas of childhood T-cell acute lymphoblastic leukaemia (T-ALL). They identified a distinctive cancer cell state that correlates with high risk, treatment refractory T-ALL.

The surge in critically ill patients has pressured hospitals to expand their intensive care unit capacities and critical care staff. This was difficult given the country's shortage of intensivists. This paper describes the implementation of a multidisciplinary central line placement team and its impact in reducing the vascular access workload of ICU physicians during the height of the COVID-19 pandemic. Vascular surgeons, interventionalists, and anesthesiologists, were redeployed to the ICU Access team to place central and arterial lines. Nurses with expertise in vascular access were recruited to the team to streamline consultation and assist with line placement. While 51 central and arterial lines were placed per 100 ICU patients in 2019, there were 87 central and arterial lines placed per 100 COVID-19 ICU patients in the sole month of April, 2020. The ICU Access Team placed 107 of the 226 vascular access devices in April 2020, reducing the procedure-related workload of ICU treating teams by 46%. The ICU Access Team was able to complete a large proportion of vascular access insertions without reported complications. Given another mass casualty event, this ICU Access Team could be reassembled to rapidly meet the increased vascular access needs of patients.