Tracking the gene expression programs and clonal relationships that underlie mast, myeloid, and T lineage specification from stem cells.

T cells develop from hematopoietic progenitors in the thymus and protect against pathogens and cancer. However, the emergence of human T cell-competent blood progenitors and their subsequent specification to the T lineage have been challenging to capture in real time. Here, we leveraged a pluripotent stem cell differentiation system to understand the transcriptional dynamics and cell fate restriction events that underlie this critical developmental process.

The effects of slope-adaptive prosthetic feet on sloped gait performance and quality in unilateral transtibial prosthesis users: A scoping review.

Introduction: In non-impaired human locomotion, sagittal-plane slope adaptation of the foot-ankle complex is a volitional function driven by neuromotor control to support upright posture and forward ambulation. Loss of this adaptation due to transtibial amputation can lead to instability and compensatory motions as most commercially-available prosthetic feet do not permit automatic slope adjustments. A selection of slope-adaptive feet (SAF) have been developed to promote biomimetic ankle motion while ambulating over slopes.

Changes in Dynamic Mean Ankle Moment Arm in Unimpaired Walking Across Speeds, Ramps, and Stairs.

Understanding the natural biomechanics of walking at different speeds and activities is crucial to develop effective assistive devices for persons with lower-limb impairments. While continuous measures such as joint angle and moment are well-suited for biomimetic control of robotic systems, whole-stride summary metrics are useful for describing changes across behaviors and for designing and controlling passive and semi-active devices. Dynamic mean ankle moment arm (DMAMA) is a whole-stride measure representing the moment arm of the ground reaction impulse about the ankle joint-effectively, how "forefoot-dominated" or "hindfoot-dominated" a movement is.

Optimizing throughput of babies with infantile hypertrophic pyloric stenosis.

Background: Definitive surgical care is often delayed in hypertrophic pyloric stenosis (HPS). Our aim is to evaluate the effect modifiable factors in preoperative HPS management have on efficiency of care.

Methods: A retrospective review of all patients undergoing pyloromyotomy for HPS at two US children's hospitals between 2008 and 2018 was performed.

Categorization and recommendations for outcome measures for lower limb absence by an expert panel.

Background: Understanding the psychometric strengths and limitations of outcome measures for use with people with lower limb absence (LLA) is important for selecting measures suited to evaluating patient outcomes, answering clinical and research questions, and informing health care policy. The aim of this project was to review the current psychometric evidence on outcome measures in people with LLA to determine which measures should be included in a stakeholder consensus process.

Methods: An expert panel was assembled, and a 3-stage review process was used to categorize outcome measures identified in a systematic literature review into 3 distinct categories (recommended for measures with better than adequate psychometric properties; recommended with qualification; and unable to recommend).

Sensorimotor function and standing balance in older adults with transtibial limb loss.

Background: Limited research has focused on older prosthesis users despite the expected compounded effects of age and amputation on sensorimotor function, balance, and falls. This study compared sensorimotor factors and standing balance between older individuals with and without transtibial amputation, hypothesizing that prosthesis users would demonstrate worse sensorimotor function. Secondarily we assessed the relationship between standing balance and somatosensation in prosthesis users.

Validating a fear-of-falling-related activity avoidance scale in lower limb prosthesis users.

Background: Limited available data suggest that fear of falling (FoF) may be common among lower limb prosthesis users (LLPUs) and associated with negative rehabilitation outcomes. The impact of FoF on outcomes may be exacerbated when fear leads to self-imposed declines in activity. There is a need to identify the validity of fear-of-falling-related activity avoidance scales in LLPUs.

Socket-residuum coupling integrity affects perception of external stimuli: Effects of altering the transtibial interface using vacuum-assisted suspension.

Background: Relative movement between the socket and residual limb can impair function in prosthesis users. It is plausible that, in addition to its mechanical effect, the integrity of the socket-residuum interface influences the ability of an individual to sense tactile cues through the prosthesis. Vacuum-assisted suspension (VAS) has been shown to reduce relative movement at this interface, providing a means to test this premise.

Internal iliac artery aneurysm in a patient with proximal occlusion at its origin.

We present the case of an 87-year-old man with a ruptured right internal iliac artery aneurysm with hemoperitoneum. The right internal iliac artery aneurysm appeared to fill from the retrograde profunda femoris artery in the setting of a previously repaired abdominal aortic aneurysm with aorta-bi-iliac bypass with ligation of the bilateral internal iliac arteries. Abdominal computed tomography revealed an aneurysm of the right internal iliac artery measuring 8.

Dynamic Balance During Walking in Transfemoral Prosthesis Users: Step-to-Step Changes in Whole-Body and Segment Angular Momenta.

Transfemoral prosthesis users (TFPUs) typically have a high risk of balance loss and falling. Whole-body angular momentum ( [Formula: see text] is a common measure for assessing dynamic balance during human walking. However, little is known about how unilateral TFPUs maintain this dynamic balance through segment-to-segment cancellation strategies.

Sex biased human thymic architecture guides T cell development through spatially defined niches.

Within the thymus, regulation of the cellular cross-talk directing T cell development is dependent on spatial interactions within specialized niches. To create a holistic, spatially defined map of tissue niches guiding postnatal T cell development we employed the multidimensional imaging platform CO-detection by indEXing (CODEX), as well as CITE-seq and ATAC-seq. We generated age-matched 4-5-month-old postnatal thymus datasets for male and female donors, and identify significant sex differences in both T cell and thymus biology.

Systematic Assessment of Prosthesis Stiffness on User Biomechanics Using the Lower Leg Trajectory Error Framework and Its Implication for the Design and Evaluation of Ankle-Foot Prostheses.

Advances in understanding the effects the mechanical characteristics of prosthetic feet on user biomechanics have enabled passive prostheses to improve the walking pattern of people with lower limb amputation. However, there is no consensus on the design methodology and criteria required to maximize specific user outcomes and fully restore their mobility. The Lower Leg Trajectory Error (LLTE) framework is a novel design methodology based on the replication of lower leg dynamics.

DLL4 and VCAM1 enhance the emergence of T cell-competent hematopoietic progenitors from human pluripotent stem cells.

T cells show tremendous efficacy as cellular therapeutics. However, obtaining primary T cells from human donors is expensive and variable. Pluripotent stem cells (PSCs) have the potential to provide a renewable source of T cells, but differentiating PSCs into hematopoietic progenitors with T cell potential remains an important challenge.

Defining Duplex Ultrasound Criteria for In-Stent Restenosis of the Carotid Artery Using Computed Tomographic Angiography.

Introduction Duplex ultrasound (DUS) velocity measurement is the preferred method for evaluating carotid artery stenosis. However, velocity criteria based upon native carotid arteries may not apply to internal carotid artery stents. Previously, catheter-based angiography was used to determine DUS velocity criteria for in-stent restenosis (ISR), but conventional angiography is invasive and can be limited.

The Use of Paclitaxel-Coated Devices in the Treatment of Peripheral Arterial Disease is Not Associated With Increased Mortality or Amputations.

Background: Strategies for the most effective treatment for peripheral arterial disease (PAD) remain controversial among clinicians. Several trials have shown improved primary patency of femoropopliteal interventions with the utilization of paclitaxel-coated balloons or stents compared to conventional balloons or stents. However, a 2018 meta-analysis suggested an increased mortality risk for patients receiving drug-coated balloons or stents (DCBS), resulting in an international pause in the use of DCBS.

Biomechanical evaluation over level ground walking of user-specific prosthetic feet designed using the lower leg trajectory error framework.

The walking pattern and comfort of a person with lower limb amputation are determined by the prosthetic foot's diverse set of mechanical characteristics. However, most design methodologies are iterative and focus on individual parameters, preventing a holistic design of prosthetic feet for a user's body size and walking preferences. Here we refined and evaluated the lower leg trajectory error (LLTE) framework, a novel quantitative and predictive design methodology that optimizes the mechanical function of a user's prosthesis to encourage gait dynamics that match their body size and desired walking pattern.

Comparison of Ischial Containment and Subischial Sockets Effect on Gait Biomechanics in People With Transfemoral Amputation: A Randomized Crossover Trial.

Objective: To compare gait biomechanics of the Northwestern University Flexible Sub-Ischial Vacuum (NU-FlexSIV) Socket to the ischial containment (IC) socket.

Design: Randomized crossover trial with 2, 7-week periods.

Setting: Private prosthetic clinics and university research laboratory.

Effects of walking speed and prosthetic knee control type on external mechanical work in transfemoral prosthesis users.

During human locomotion, each limb performs step-to-step work on the body center of mass to maintain forward walking. This energy exchange relies on physiological mechanisms which are altered or impaired in transfemoral prosthesis users (TFPUs). Exploring step-to-step energy exchange modifications displayed by TFPUs at greater walking speeds may provide insight into their means for improving gait efficiency.

Effects of women's footwear on the mechanical function of heel-height accommodating prosthetic feet.

The loaded mechanical function of transtibial prostheses that result from the clinical assembly, tuning, and alignment of modular prosthetic components can directly influence an end user's biomechanics and overall mobility. Footwear is known to affect prosthesis mechanical properties, and while the options of footwear are limited for most commercial feet due to their fixed geometry, there exists a selection of commercial prosthetic feet that can accommodate a moderate rise in heel height. These feet are particularly relevant to women prosthesis users who often desire to don footwear spanning a range of heel heights.