Generation and Characterization of Erythroid Cells from Human Embryonic Stem Cells and Induced Pluripotent Stem Cells: An Overview

Because of the imbalance in the supply and demand of red blood cells (RBCs), especially for alloimmunized patients or patients with rare blood phenotypes, extensive research has been done to generate therapeutic quantities of mature RBCs from hematopoietic stem cells of various sources, such as bone marrow, peripheral blood, and cord blood. Since human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) can be maintained indefinitely in vitro, they represent potentially inexhaustible sources of donor-free RBCs. In contrast to other ex vivo stem-cell-derived cellular therapeutics, tumorigenesis is not a concern, as RBCs can be irradiated without marked adverse effects on in vivo function. Here, we provide a comprehensive review of the recent publications relevant to the generation and characterization of hESC- and iPSC-derived erythroid cells and discuss challenges to be met before the eventual realization of clinical usage of these cells

Robust Affinity Propagation using Preference Estimation

Affinity propagation is a novel unsupervised learning algorithm for exemplar-based clustering without the priori knowledge of the number of clusters (NC). In this article, the influence of the “preference” on the accuracy of AP output is addressed. We present a robust AP clustering method, which estimates what preference value could possibly yield an optimal clustering result. To demonstrate the performance promotion, we apply the robust AP on picture clustering, using local SIFT, global MPEG-7 CLD, and the proposed preference as the input of AP. The experimental results show that over 40% enhancement of ARI accuracy for several image datasets

Adaptive RF Pigtail Probe Modeling for De-embedding of RF Measurements

This disclosure describes techniques for accurate estimation and de-embedding of the effects of pigtail probes in circuits. An adaptive pigtail model is developed and described that can accurately de-embed the effects of pigtail probes in digital circuits. Example parameters are identified that include pigtail length, tip length, pigtail tilt degree, ground distance, and solder amount. A pigtail simulation model is developed to model the soldered pigtail probe. The dependency of circuit impedance on the identified parameters is determined by experimentation which indicates that circuit performance can be boosted by short ground distance lengths, low tilt angles, thick support wires, short pin and cable lengths, and thick support wires. The pigtail model can be utilized to derive de-embedded results for different pigtail probe configurations without a need for explicitly measuring de-embedded results for those configurations

Soft-tissue Tumor Differentiation Using 3D Power Doppler Ultrasonography With Echo-contrast Medium Injection

BackgroundWe aimed to evaluate the ability of 3-dimensional power Doppler ultrasonography to differentiate soft-tissue masses from blood flow and vascularization with contrast medium.MethodsTwenty-five patients (mean age, 44.1 years; range, 12-77 years) with a palpable mass were enrolled in this study. Volume data were acquired using linear and convex 3-dimensional probes and contrast medium injected manually by bolus. Data were stored and traced slice by slice for 12 slices. All patients were scanned by the same senior sonologist. The vascular index (VI), flow index (FI), and vascular-flow index (VFI) were automatically calculated after the tumor was completely traced. All tumors were later confirmed by pathology.ResultsThe study included 8 benign (mean, 36.5 mL; range, 2.4-124 mL) and 17 malignant (mean, 319.4 mL; range, 9.9-1,179.6 mL) tumors. Before contrast medium injection, mean VI, FI and VFI were, respectively, 3.22, 32.26 and 1.07 in benign tumors, and 1.97, 29.33 and 0.67 in malignant tumors. After contrast medium injection, they were, respectively, 20.85, 37.33 and 8.52 in benign tumors, and 40.12, 41.21 and 17.77 in malignant tumors. The mean differences between with and without contrast injection for VI, FI and VFI were, respectively, 17.63, 5.07 and 7.45 in benign tumors, and 38.15, 11.88 and 16.55 in malignant tumors. Tumor volume, VI, FI and VFI were not significantly different between benign and malignant tumors before and after echo-contrast medium injection. However, VI, FI and VFI under self-differentiation (differences between with and without contrast injection) were significantly different between malignant and benign tumors.ConclusionThree-dimensional power Doppler ultrasound is a valuable tool for differential diagnosis of soft-tissue tumors, especially with the injection of an echo-contrast medium

Trisomy Correction in Down Syndrome Induced Pluripotent Stem Cells

SummaryHuman trisomies can alter cellular phenotypes and produce congenital abnormalities such as Down syndrome (DS). Here we have generated induced pluripotent stem cells (iPSCs) from DS fibroblasts and introduced a TKNEO transgene into one copy of chromosome 21 by gene targeting. When selecting against TKNEO, spontaneous chromosome loss was the most common cause for survival, with a frequency of ∼10−4, while point mutations, epigenetic silencing, and TKNEO deletions occurred at lower frequencies in this unbiased comparison of inactivating mutations. Mitotic recombination events resulting in extended loss of heterozygosity were not observed in DS iPSCs. The derived, disomic cells proliferated faster and produced more endothelia in vivo than their otherwise isogenic trisomic counterparts, but in vitro hematopoietic differentiation was not consistently altered. Our study describes a targeted removal of a human trisomy, which could prove useful in both clinical and research applications

Bizarre parosteal osteochondromatous proliferation on a phalanx with periosteal erosion

SummaryBizarre parosteal osteochondromatous proliferation (BPOP) is an uncommon benign hand tumor with a high rate of local recurrence, marked proliferative activity, and an atypical histological appearance. The aim of this paper is to present a rare and illustrative example of BPOP with periosteal erosion. A 64-year-old male presented with a 10-year history of a mass, measuring approximately 3 cm in diameter, on the dorsal aspect of the right index finger. On physical examination, the mass was hard, indolent, and located at the level of the proximal phalanx. Roentgenograms displayed a soft tissue mass over the right index finger with erosion of the periosteum. Magnetic resonance imaging revealed a few well-defined lobulated tumors over the right index finger proximal interphalangeal joint with periosteal reaction. The soft tissue tumors were excised and found to have soft consistencies. Pathological findings demonstrated that the tumor was compatible with BPOP. BPOP is a benign but locally aggressive fibro-osseous mass yielding radiographic findings that bear striking clinical similarities to those of other diseases, such as osteochondroma, osteosarcoma, and myositis ossificans. As the radiographic findings of BPOP are equivocal, the differential diagnosis must be based on the pathological results. With this case report, we aim to inform physicians that a hand tumor with an aggressive clinical picture may be benign in origin

Drumhead Surface States and Topological Nodal-Line Fermions in TlTaSe2

A topological nodal-line semimetal is a new condensed matter state with one-dimensional bulk nodal lines and two-dimensional drumhead surface bands. Based on first-principles calculations and our effective k . p model, we propose the existence of topological nodal-line fermions in the ternary transition- metal chalcogenide TlTaSe2. The noncentrosymmetric structure and strong spin-orbit coupling give rise to spinful nodal-line bulk states which are protected by a mirror reflection symmetry of this compound. This is remarkably distinguished from other proposed nodal-line semimetals such as Cu3NPb(Zn) in which nodal lines exist only in the limit of vanishing spin-orbit coupling. We show that the drumhead surface states in TlTaSe2, which are associated with the topological nodal lines, exhibit an unconventional chiral spin texture and an exotic Lifshitz transition as a consequence of the linkage among multiple drumhead surface-state pockets.Comment: Related papers at http://physics.princeton.edu/zahidhasangroup/index.htm