Search

Applied a between-grade design to the estimation of school effectiveness and examined the agreement between the resulting estimates and those obtained from the traditional statistical control model. Analysis of data from 11,099 intermediate-grade students in Israel shows that neither method produced estimates that were stable across grade level and achievement domain, raising questions about the concept of school effectiveness. (SLD)

Background: Pluripotent cell-derived islet replacement therapy offers promise for treating Type 1 diabetes (T1D), but concerns about uncontrolled cell proliferation and tumorigenicity present significant safety challenges. To address the safety concern, this study aims to establish a proof-of-concept for a glucose-responsive, insulin-secreting cell line integrated with a built-in FailSafe kill-switch., Method: We generated β cell-induced progenitor-like cells (βiPLCs) from primary mouse pancreatic β cells through interrupted reprogramming. Then, we transcriptionally linked our FailSafe (FS) kill-switch, HSV-thymidine kinase (TK), to Cdk1 gene using a CRISPR/Cas9 knock-in strategy, resulting in a FailSafe βiPLC line, designated as FSβiPLCs. Subsequently we evaluated and confirmed the functionality of the drug-inducible kill-switch in FSβiPLCs at different ganciclovir (GCV) concentrations using our PDMS-based transcapillary microfluidic system. Finally, we assessed the functionality of FSβiPLCs by characterizing the dynamics of insulin secretion in response to changes in glucose concentration using our microfluidic perfusion glucose-stimulated insulin secretion (GSIS) assay-on- chip., Results: The βiPLCs exhibited Ins1, Pdx1 and Nkx6.1 expression, and glucose responsive insulin secretion, the essential properties of pancreatic beta cells. The βiPLCs were amenable to genome editing which allowed for the insertion of the kill-switch into the 3'UTR of Cdk1, confirmed by PCR genotyping. Our transcapillary microfluidic system confirmed the functionality of the drug-inducible kill-switch in FSβiPLCs, showing an effective cell ablation of dividing cells from a heterogeneous cell population at different ganciclovir (GCV) concentrations. The Ki67 expression assessment further confirmed that slow- or non-dividing cells in the FSβiPLC population were resistant to GCV. Our perfusion glucose-stimulated insulin secretion (GSIS) assay-on-chip revealed that the resistant non-dividing FSβiPLCs exhibited higher levels of insulin secretion and glucose responsiveness compared to their proliferating counterparts., Conclusions: This study establishes a proof-of-concept for the integration of a FailSafe kill-switch system into a glucose-responsive, insulin-secreting cell line to address the safety concerns in stem cell-derived cell replacement treatment for T1D. The microfluidic systems provided valuable insights into the functionality and safety of these engineered cells, demonstrating the potential of the kill-switch to reduce the risk of tumorigenicity in pluripotent cell-derived insulin-secreting cells., Competing Interests: Declarations. Ethics approval and consent to participate: Details of ethics approvals: Title of the approved project: Characterizing the reprogramming process in vivo by using pancreatic endocrine cells to compensate for the beta cell ablated pancreas. Name of the institutional approval committee: The ethics board of The Centre for Phenogenomics (TCP). Approval number: AUP#0182. Date of approval (dd-mm-yy): 08–03-2018. Authors confirm that no human participant was involved in this study; thus, ‘patient consent’ was not applicable for this study. Consent for publication: All authors confirm their consent for publication. Competing interests: The authors declare that they have no competing interests., (© 2024. The Author(s).)

Background: Immune checkpoint inhibitor (ICI) therapies have become increasingly popular treatment options for patients with cancer, even for patients in non-metastatic settings. Survival and responses have been reported for individual tumor types, but little is known about these outcomes, collectively. We sought to provide an overview of overall survival (OS) and progression-free survival (PFS) in ICI drugs tested in registration trials., Methods: In a cross-sectional analysis of US FDA oncology ICI drug approvals (2011-2023), we searched for supporting ICI registration trials. We characterized these trials, regarding differences in median OS and PFS between patients in intervention and control arm participants in ICI registration trials; percentage of patients who receive ICI crossover; and whether there is correlation between the percentage of crossover and differences in OS or PFS., Results: Fifty-six (54.4 %) approvals had trials that reported median OS for both intervention and control arms (median difference was 2.8 months; IQR: 2.2 to 5.0 months). Sixty-five (63.1 %) approvals had trials that reported PFS data for both arms (median of 0.9 months; IQR: -0.2 to 3.0 months). Subsequent therapy was common (median=18.9 %) and was significantly correlated with a higher difference in median OS in all studies with reported differences (R2 =0.15; p = 0.001)., Conclusion: ICIs are increasingly used in the treatment of cancer, yet the median OS improvement is modest, and many ICIs have not been tested for OS benefit. OS is the outcome most meaningful for patients, and drug regulation should require better testing and reporting of these data., Competing Interests: Declaration of Competing Interest V.P. receives research funding from Arnold Ventures through a grant made to UCSF, and royalties for books and writing from Johns Hopkins Press, MedPage, and the Free Press. He declares consultancy roles with UnitedHealthcare and OptumRX; He hosts the podcasts, Plenary Session, VPZD, Sensible Medicine, writes the newsletters, Sensible Medicine, the Drug Development Letter and VP's Observations and Thoughts, and runs the YouTube channel Vinay Prasad MD MPH, which collectively earn revenue on the platforms: Patreon, YouTube and Substack. AH, MSK, and JE have no disclosures to report., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Hypertension (HTN) is a major cardiovascular risk factor and a significant contributor to disease burden in the United States. Despite therapeutic advances, gaps remain between clinical trials and practice. This study aims to bridge those gaps by evaluating antihypertensive strategies. This was a retrospective analysis of HTN patients seen at a hospital clinic from 2016 to 2022 with 3- and 12-month follow-up appointments. Demographics, history, blood pressure (BP), and medication regimen were recorded. Treatment strategies were categorized as follows: adding medication (AM), increasing dosage (ID), switching medications (SM), dropped medications (DrM), or no change (NC). Changes in systolic blood pressure (SBP) were compared using linear regressions to assess the efficacy of HTN management. Of 873 patient charts reviewed, 332 patients were included. The AM group had an adjusted ∆SBP of -11 mm Hg at 3 months ( p  < 0.001) and -9 mm Hg at 12 months ( p  = 0.006). The ID group had an ∆SBP of -8.5 mm Hg at 3 months ( p  = 0.074) and -7 mm Hg at 12 months ( p  = 0.3). ∆SBP between the AM and ID groups was not statistically significant ( p  = 0.8). SM was associated with an ∆SBP of -3 mm Hg at 3 months ( p  = 0.6) and -3 mm Hg at 12 months ( p  = 0.7). There are meaningful differences in SBP reduction between antihypertensive medication adjustment strategies. AM had the greatest effect on lowering SBP, with ID having a slightly lesser effect. The difference in ∆SBP between the AM versus ID groups was not significant. While further study with a larger dataset is warranted, our findings highlight trends in the efficacy of HTN management strategies to help guide therapeutic regimens., Competing Interests: Conflict of Interest None declared., (International College of Angiology. This article is published by Thieme.)

Background: The US Food and Drug Administration (FDA) has expanded the use of surrogate markers in drugs approved for oncology/hematology indications. This has likely resulted in a greater number of approvals and possibly drugs coming to market faster, but it is unknown whether these drugs also improve overall survival (OS) for patients taking them., Methods: We sought to estimate the percentage of oncology drugs that have shown to improve OS in a cross-sectional analysis of US FDA oncology drug approvals (2006-2023). We searched for OS data in registration trials and the peer-reviewed literature., Results: We found 392 oncology drug approvals. Eighty-seven (22%) drug approvals were based on OS, 147 drug approvals were later tested for OS benefit (38% of all approvals and 48% of drugs approved on a surrogate), and 130 (33%) have yet to be tested for OS benefit. Of the 147 drug approvals later tested for OS, 109 (28% of all approvals and 74% of drugs later tested for OS) have yet to show OS benefit, whereas 38 (10% of all approvals and 26% of drugs later tested for OS benefit) were later shown to have OS benefit. In total, 125 out of 392 (32%) drugs approved for any indication have been shown to improve OS benefit at some point, and 267 (68%) have yet to show approval., Conclusion: About 32% of all oncology drug approvals have evidence for an improvement in OS. Higher standards are needed in drug regulation to ensure that approved drugs are delivering better patient outcomes, specifically in regards to survival., (© 2024 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: This study aimed to investigate the efficacy and safety of subcutaneous injection of peginterferon lambda in patients hospitalized with COVID-19., Methods: In this study (NCT04343976), patients admitted to hospital with COVID-19 confirmed by RT-PCR from nasopharyngeal swab were randomly assigned within 48 h to receive peginterferon lambda or placebo in a 1:1 ratio. Participants were subcutaneously injected with a peginterferon lambda or saline placebo at baseline and day 7 and were followed up until day 14., Results: We enrolled 14 participants; 6 participants (85.7%) in the peginterferon lambda group and 1 participant (14.3%) in the placebo group were treated with remdesivir prior to enrollment. Fifty percent of participants were SARS-CoV-2 RNA negative at baseline although they tested SARS-CoV-2 RNA positive within 48 h of randomization. Among participants who were SARS-CoV-2 positive at baseline, 2 out of 5 participants (40%) in the peginterferon lambda group became negative at day 14, while 0 out of 2 participants (0%) in the placebo group achieved negativity for SARS-CoV-2 by day 14 ( p  > 0.05). The median change in viral load (log copies per ml) was +1.72 (IQR -2.78 to 3.19) in the placebo group and -2.22 (IQR -3.24 to 0.55) in the peginterferon lambda group at day 14 ( p  = 0.24). Symptomatic changes did not differ between the two groups. Peginterferon lambda was well tolerated with a few treatment-related adverse effects., Conclusion: Peginterferon lambda appears to accelerate SARS-CoV-2 viral load decline and improve plasma disease progression markers in hospitalized patients with COVID-19., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Kim, Elbaz, Jilg, Gustafson, Xu, Hatipoglu, Nohelty, Kim and Chung.)

Engineered bacteria could perform many functions in the environment, for example, to remediate pollutants, deliver nutrients to crops or act as in-field biosensors. Model organisms can be unreliable in the field, but selecting an isolate from the thousands that naturally live there and genetically manipulating them to carry the desired function is a slow and uninformed process. Here, we demonstrate the parallel engineering of isolates from environmental samples by using the broad-host-range XPORT conjugation system (Bacillus subtilis mini-ICEBs1) to transfer a genetic payload to many isolates in parallel. Bacillus and Lysinibacillus species were obtained from seven soil and water samples from different locations in Israel. XPORT successfully transferred a genetic function (reporter expression) into 25 of these isolates. They were then screened to identify the best-performing chassis based on the expression level, doubling time, functional stability in soil, and environmentally-relevant traits of its closest annotated reference species, such as the ability to sporulate and temperature tolerance. From this library, we selected Bacillus frigoritolerans A3E1, re-introduced it to soil, and measured function and genetic stability in a contained environment that replicates jungle conditions. After 21 months of storage, the engineered bacteria were viable, could perform their function, and did not accumulate disruptive mutations., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Revealing the molecular events associated with reprogramming different somatic cell types to pluripotency is critical for understanding the characteristics of induced pluripotent stem cell (iPSC) therapeutic derivatives. Inducible reprogramming factor transgenic cells or animals-designated as secondary (2°) reprogramming systems-not only provide excellent experimental tools for such studies but also offer a strategy to study the variances in cellular reprogramming outcomes due to different in vitro and in vivo environments. To make such studies less cumbersome, it is desirable to have a variety of efficient reprogrammable mouse systems to induce successful mass reprogramming in somatic cell types. Here, we report the development of two transgenic mouse lines from which 2° cells reprogram with unprecedented efficiency. These systems were derived by exposing primary reprogramming cells containing doxycycline-inducible Yamanaka factor expression to a transient interruption in transgene expression, resulting in selection for a subset of clones with robust transgene response. These systems also include reporter genes enabling easy readout of endogenous Oct4 activation (GFP), indicative of pluripotency, and reprogramming transgene expression (mCherry). Notably, somatic cells derived from various fetal and adult tissues from these 2° mouse lines gave rise to highly efficient and rapid reprogramming, with transgene-independent iPSC colonies emerging as early as 1 wk after induction. These mouse lines serve as a powerful tool to explore sources of variability in reprogramming and the mechanistic underpinnings of efficient reprogramming systems.

Introduction: For epidermal growth factor receptor mutation-positive (EGFRm) non-small-cell lung cancer (NSCLC), EGFR-tyrosine kinase inhibitors (EGFR-TKIs) are the preferred first-line (1 L) treatment in the advanced setting. Osimertinib, a third-generation EGFR-TKI, received full approval in 2017 for second-line (2 L) treatment of EGFR T790M-positive NSCLC. The REFLECT study characterizes real-world treatment/testing patterns, attrition rates, and outcomes in patients with EGFRm advanced NSCLC treated with 1 L first-/second-generation (1G/2G) EGFR-TKIs before 1 L osimertinib approval., Methods: Retrospective chart review (NCT04031898) of European/Israeli adults with EGFRm unresectable locally advanced/metastatic NSCLC, initiating 1 L 1G/2G EGFR-TKIs 01/01/15-30/06/18 (index date)., Results: In 896 patients (median follow-up of 21.5 months), the most frequently initiated 1 L EGFR-TKI was afatinib (45%). Disease progression was reported in 81%, including 10% (86/896) who died at 1 L. By the end of study, most patients discontinued 1 L (85%), of whom 33% did not receive 2 L therapy. From index, median 1 L real-world progression-free survival was 13.0 (95% confidence interval (CI): 12.3-14.1) months; median overall survival (OS) was 26.2 (95% CI: 23.6-28.4) months. 71% of patients with 1 L progression were tested for T790M; 58% were positive. Of those with T790M, 95% received osimertinib in 2 L or later. Central nervous system (CNS) metastases were recorded in 22% at index, and 15% developed CNS metastases during treatment (median time from index 13.5 months). Median OS was 19.4 months (95% CI: 17.1-22.1) in patients with CNS metastases at index, 24.8 months (95% CIs not available) with CNS metastases diagnosed during treatment, and 30.3 months (95% CI: 27.1, 33.8) with no CNS metastases recorded., Conclusion: REFLECT is a large real-world study describing treatment patterns prior to 1 L osimertinib availability for EGFRm advanced NSCLC. Given the attrition rates highlighted in the study and the impact of CNS progression on outcomes, offering a 1 L EGFR-TKI with CNS penetration may improve patient outcomes in this treatment setting., Competing Interests: Conflict of interest statement: The authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: AA received honoraria from AstraZeneca, BMS, Eli Lilly, MSD, Pfizer, Roche and Takeda outside the submitted work. MH received honoraria for speaker’s bureau from AstraZeneca, BMS, Boehringer Ingelheim, MSD, Roche and Takeda, and served on advisory boards for AstraZeneca, BMS, Boehringer Ingelheim, MSD, Roche and Takeda. UJ served on advisory councils or committees for AstraZeneca, Boehringer Ingelheim, MSD and Roche, and received honoraria from AstraZeneca, BMS, Boehringer Ingelheim, MSD, Pfizer and Roche. ED served on advisory councils or committees for AstraZeneca, BMS, Novartis, Pfizer, Roche, Sanofi, and Takeda, received honoraria from AstraZeneca, BMS, MSD, Novartis, Pfizer, Roche, Sanofi, Pfizer, and Takeda and received consulting fees from AstraZeneca, BMS, Novartis, Pfizer, Roche, Sanofi, and Takeda, all outside the submitted work. AC served on advisory councils or committees for ASTRA, Boehringer Ingelheim and MSD, received honoraria from ASTRA, BMS, MSD and Roche and received consulting fees from ASTRA and Boehringer Ingelheim, outside the submitted work. AP has received personal fees and non-financial support from AstraZeneca, BMS, Boehringer Ingelheim, Pfizer and Roche, and personal fees from MSD, and Takeda outside the submitted work. TC served on advisory councils or committees for Amgen, Astellas, AstraZeneca, BMS, Boehringer Ingelheim Janssen, MSD. Roche, and Pfizer outside the submitted work. ISD has no disclosures to declare. JE and JA are employees of AstraZeneca. RO is an employee of AstraZeneca AG and owns stocks/shares in AstraZeneca AG. NP served on advisory councils or committees for AstraZeneca, Bayer, Boehringer Ingelheim, BMS, Eli Lilly, FoundationMedicine, Guardant360, Merck, MSD, Novartis, NovellusDx, Pfizer, Roche and Takeda, received honoraria and consulting fees from AstraZeneca, Bayer, Boehringer Ingelheim, BMS, Eli Lilly, FoundationMedicine, Guardant360, Merck, MSD, Novartis, NovellusDx, Pfizer, Roche and Takeda, and received grants or funds from AstraZeneca, Bayer, Boehringer Ingelheim, BMS, Eli Lilly, Merck, MSD, Novartis, Pfizer, Roche and Takeda., (© The Author(s), 2021.)

DNA nanotechnology is leading the field of in vitro molecular-scale device engineering, accumulating to a dazzling array of applications. However, while DNA nanostructures' function is robust under in vitro settings, their implementation in real-world conditions requires overcoming their rapid degradation and subsequent loss of function. Viruses are sophisticated supramolecular assemblies, able to protect their nucleic acid content in inhospitable biological environments. Inspired by this natural ability, we engineered in vitro and in vivo technologies, enabling the encapsulation and protection of functional DNA nanostructures inside MS2 bacteriophage virus-like particles (VLPs). We demonstrate the ssDNA-VLPs nanocomposites' (NCs) abilities to encapsulate single-stranded-DNA (ssDNA) in a variety of sizes (200-1500 nucleotides (nt)), sequences, and structures while retaining their functionality. Moreover, by exposing these NCs to hostile biological conditions, such as human blood serum, we exhibit that the VLPs serve as an excellent protective shell. These engineered NCs pose critical properties that are yet unattainable by current fabrication methods.

Background: Georgia is leading one of the world's first hepatitis C (HCV) elimination programs alongside interventions to combat a HIV epidemic concentrated among high-risk groups. Although progress has been substantial, neither strategy accounts for the nearly 150,000 internally displaced persons residing in collective centers (CC-IDPs) who are susceptible to deeply integrated risk environments that could promote infection. Achieving dedicated goals for HCV elimination and HIV suppression requires a clear understanding of the risks facing CC-IDPs., Objectives: This literature review aims to consolidate what is known about the socio-economic and physical/mental health status of IDPs living in collective centers in Georgia, and to assess their vulnerability to HIV and HCV in light of local and global epidemiological trends., Methods: Sources were compiled from journal publications, reports by government ministries and transnational organizations, and the Integrated Household Survey database (2009-2018; updated annually by the National Statistics Office of Georgia) through manual searches in PUBMED, Google Scholar and Search, ProQuest, and digital repositories of government offices., Findings: Reports indicate that CC-IDPs are more susceptible to poverty, poor living conditions, mental illness, disability, substance use, and in some cases infectious disease; although, the correlation is not always present and subject to variability. These factors were linked to increased transmission and acquisition of HIV/HCV in both displacement and non-displacement contexts abroad. The geographic concentration of HIV/HCV in areas with greater clusters of CC-IDPs, and shared characteristics with local high-risk groups, indicate the possibility of inordinate transmission among CC-IDPs in Georgia., Conclusions: The disproportionate prevalence of psychosocial and clinical harms among CC-IDPs testifies to the serious potential of a greater burden of HIV and hepatitis C. Going forward, targeted research is needed to inform interventions and clarify the health status of CC-IDPs in Georgia., Competing Interests: The author has no competing interests to declare., (Copyright: © 2020 The Author(s).)

The ability to create nanoscaffolds within living cells using DNA has the potential to become a powerful tool in synthetic biology. However, to date, genetically encoded DNA nanostructures are limited to simple architecture due to the lack of genetic parts that can produce multiple ssDNAs in a single bacterium. Here, we develop a system that overcomes this challenge by using a single oligo gene mimicking operons. This was achieved by converting a noncoding RNA into a long ssDNA that self-cleaves into multiple ssDNAs using R3-DNAzymes (DNAzyme-based operon). We demonstrate the ability to apply the DNAzyme-based operon to produce a four-ssDNA crossover nanostructure (25 nm) that recruits split YFPs when properly assembled. This system enables the formation of more complex DNA nanostructures in vivo and thus paves the way to further integrate the field of DNA nanotechnology into living bacteria for basic biology, bioengineering, and medicine applications.

In nature, intracellular microcompartments have evolved to allow the simultaneous execution of tightly regulated complex processes within a controlled environment. This architecture serves as the blueprint for the construction of a wide array of artificial cells. However, such systems are inadequate in their ability to confine and sequentially control multiple central dogma activities (transcription, translation, and post-translational modifications) resulting in a limited production of complex biomolecules. Here, an artificial cell-on-a-chip comprising hierarchical compartments allowing the processing and transport of products from transcription, translation, and post-translational modifications through connecting channels is designed and fabricated. This platform generates a tightly controlled system, yielding directly a purified modified protein, with the potential to produce proteoform of choice. Using this platform, the full ubiquitinated form of the Parkinson's disease-associated α-synuclein is generated starting from DNA, in a single device. By bringing together all central dogma activities in a single controllable platform, this approach will open up new possibilities for the synthesis of complex targets, will allow to decipher diverse molecular mechanisms in health and disease and to engineer protein-based materials and pharmaceutical agents., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The ability to generate induced pluripotent stem cells from differentiated cell types has enabled researchers to engineer cell states. Although studies have identified molecular networks that reprogram cells to pluripotency, the cellular dynamics of these processes remain poorly understood. Here, by combining cellular barcoding, mathematical modeling, and lineage tracing approaches, we demonstrate that reprogramming dynamics in heterogeneous populations are driven by dominant "elite" clones. Clones arise a priori from a population of poised mouse embryonic fibroblasts derived from Wnt1-expressing cells that may represent a neural crest-derived population. This work highlights the importance of cellular dynamics in fate programming outcomes and uncovers cell competition as a mechanism by which cells with eliteness emerge to occupy and dominate the reprogramming niche., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

The field of DNA nanotechnology has harnessed the programmability of DNA base pairing to direct single-stranded DNAs (ssDNAs) to assemble into desired 3D structures. Here, we show the ability to express ssDNAs in Escherichia coli (32-205 nt), which can form structures in vivo or be purified for in vitro assembly. Each ssDNA is encoded by a gene that is transcribed into non-coding RNA containing a 3'-hairpin (HTBS). HTBS recruits HIV reverse transcriptase, which nucleates DNA synthesis and is aided in elongation by murine leukemia reverse transcriptase. Purified ssDNA that is produced in vivo is used to assemble large 1D wires (300 nm) and 2D sheets (5.8 μm(2)) in vitro. Intracellular assembly is demonstrated using a four-ssDNA crossover nanostructure that recruits split YFP when properly assembled. Genetically encoding DNA nanostructures provides a route for their production as well as applications in living cells.

Reprogramming is a dynamic process that can result in multiple pluripotent cell types emerging from divergent paths. Cell surface protein expression is a particularly desirable tool to categorize reprogramming and pluripotency as it enables robust quantification and enrichment of live cells. Here we use cell surface proteomics to interrogate mouse cell reprogramming dynamics and discover CD24 as a marker that tracks the emergence of reprogramming-responsive cells, while enabling the analysis and enrichment of transgene-dependent (F-class) and -independent (traditional) induced pluripotent stem cells (iPSCs) at later stages. Furthermore, CD24 can be used to delineate epiblast stem cells (EpiSCs) from embryonic stem cells (ESCs) in mouse pluripotent culture. Importantly, regulated CD24 expression is conserved in human pluripotent stem cells (PSCs), tracking the conversion of human ESCs to more naive-like PSC states. Thus, CD24 is a conserved marker for tracking divergent states in both reprogramming and standard pluripotent culture.

Purpose: The objectives of this study were to compare demographic, clinical, radiographic, scintigraphic, and histologic differences between the 2 main types of condylar hyperplasia (CH) and to suggest a new therapeutic management based on such findings., Methods: This was a retrospective study based on 28 patients who presented either vertical (group 1) or horizontal (group 2) forms of CH and underwent surgical treatment. Every patient had a complete preoperative clinical and radiological examination as well as a single-photon emission computed tomography scan. A histologic analysis of each resected condyle was performed. These various parameters were then compared in the 2 patient groups., Results: The mean age at time of the diagnosis was 25.8 years (range, 12-50 years), and there were 22 females and 6 males. Nineteen patients had the vertical form of CH, and 9 had the horizontal form. Scintigraphic analysis showed moderate to extensive radionucleotide uptake in cases with rapid growth. Four cases had negative single-photon emission computed tomography scan uptake, and all were vertical forms, but there was no statistically significant difference between the 2 groups. The histologic analysis showed both a global thickening of the cartilage cap and of the prechondroblastic cells layer with no statistically significant difference between the 2 groups., Conclusions: Condylar hyperplasia is a pathologic condition affecting mainly young females and whose origin remains unknown. Single-photon emission computed tomography scans as an indicator of the rapidity of the disease progress are essential in assessing the condylar hyperplasia and to guide the therapeutic approach.

The assembly of DNA machines represents a central effort in DNA nanotechnology. We report on the first DNA rotor system composed of a two-ring catenane. The DNA rotor ring rotates in dictated directions along a wheel, and it occupies three distinct sites. Hg(2+)/cysteine or pH (H(+)/OH(-)) act as fuels or antifuels in positioning the rotor ring. Analysis of the kinetics reveals directional clockwise or anticlockwise population of the target-sites (>85%), and the rotor's direction is controlled by the shortest path on the wheel.

In 2006, Shinya Yamanaka and colleagues discovered how to reprogram terminally differentiated somatic cells to a pluripotent stem cell state. The resulting induced pluripotent stem cells (iPSCs) made a paradigm shift in the field, further nailing down the disproval of the long-held dogma that differentiation is unidirectional. The prospect of using iPSCs for patient-specific cell-based therapies has been enticing. This promise, however, has been questioned in the last two years as several studies demonstrated intrinsic epigenetic and genomic anomalies in these cells. Here, we not only review the recent critical studies addressing the genome integrity during the reprogramming process, but speculate about the underlying mechanisms that could create de novo genome damage in iPSCs. Finally, we discuss how much an elevated mutation load really matters considering the safety of future therapies with cells heavily cultured in vitro., (Copyright © 2013 WILEY Periodicals, Inc.)

The preparation of a DNA rotaxane consisting of a circular nucleic acid interlocked, through hybridization, on a nucleic acid axle and stoppered by two 10-nm-sized Au nanoparticles (NPs) is described. By the tethering of 5-nm- or 15-nm-sized Au NPs on the ring, the supramolecular structure of the rotaxane is confirmed. Using nucleic acids as "fuels" and "anti-fuels", the cyclic and reversible transition of the rotaxane ring across two states is demonstrated. By the functionalization of the ring with fluorophore-modified nucleic acids in different orientations, the transitions of the rings between the sites are followed by fluorescence quenching or surface-enhanced fluorescence. The experimental results are supported by theoretical modeling.

DNA nanotechnology is a rapidly developing research area in nanoscience. It includes the development of DNA machines, tailoring of DNA nanostructures, application of DNA nanostructures for computing, and more. Different DNA machines were reported in the past and DNA-guided assembly of nanoparticles represents an active research effort in DNA nanotechnology. Several DNA-dictated nanoparticle structures were reported, including a tetrahedron, a triangle or linear nanoengineered nanoparticle structures; however, the programmed, dynamic reversible switching of nanoparticle structures and, particularly, the dictated switchable functions emerging from the nanostructures, are missing elements in DNA nanotechnology. Here we introduce DNA catenane systems (interlocked DNA rings) as molecular DNA machines for the programmed, reversible and switchable arrangement of different-sized gold nanoparticles. We further demonstrate that the machine-powered gold nanoparticle structures reveal unique emerging switchable spectroscopic features, such as plasmonic coupling or surface-enhanced fluorescence.

Nature performs complex information processing circuits, such the programmed transformations of versatile stem cells into targeted functional cells. Man-made molecular circuits are, however, unable to mimic such sophisticated biomachineries. To reach these goals, it is essential to construct programmable modular components that can be triggered by environmental stimuli to perform different logic circuits. We report on the unprecedented design of artificial pH-programmable DNA logic arrays, constructed by modular libraries of Mg(2+)- and UO(2)(2+)-dependent DNAzyme subunits and their substrates. By the appropriate modular design of the DNA computation units, pH-programmable logic arrays of various complexities are realized, and the arrays can be erased, reused, and/or reprogrammed. Such systems may be implemented in the near future for nanomedical applications by pH-controlled regulation of cellular functions or may be used to control biotransformations stimulated by bacteria.

Completion of the first meiotic division, manifested by extrusion of the first polar body (PBI), depends on proteasomal degradation of cyclin B1 and securin and the subsequent respective CDK1 inactivation and chromosome segregation. We aimed at identifying the polyubiquitin signal that mediates proteasomal action and at a better characterization of the role of CDK1 inactivation at this stage of meiosis. Microinjections of mutated ubiquitin proteins into mouse oocytes revealed that interference with lysine-11 polyubiquitin chains abrogated chromosome segregation and reduced PBI extrusion by 63% as compared to WT ubiquitin-injected controls. Inactivation of CDK1 in oocytes arrested at first metaphase by a proteasome inhibitor fully rescued PBI extrusion. However, removal of CDK1 inhibition failed to allow progression to the second metaphase, rather, inducing PBI reengulfment in 62% of the oocytes. Inhibition of either PLK1 or MEK1/2 during the first anaphase changed spindle dimensions. The PLK1 inhibitor also blocked PBI emission and prevented RhoA translocation. Our results identified lysine-11 rather than the canonic lysine-48 ubiquitin chains as the degradation signal in oocytes resuming meiosis, further disclosing that CDK1 inactivation is necessary and sufficient for PBI emission. This information significantly contributes to our understanding of faulty chromosome segregation that may lead to aneuploidy.

The Zn(2+)-dependent ligation DNAzyme is implemented as a biocatalyst for the amplified detection of a target DNA by the autonomous replication of a nucleic acid reporter unit that is generated by the catalyzed ligation process. The reporter units enhance the formation of active DNAzyme units, thus leading to the isothermal autocatalytic formation of the reporter elements. The system was further developed and applied for the amplified detection of Tay-Sachs genetic disorder mutant, with a detection limit of 1.0 × 10(-11) M. Besides providing a versatile paradigm for the amplified detection of DNA, the system reveals a new, enzyme-free, isothermal, autocatalytic mechanism that introduces means for effective programmed synthesis.

Fundamental aspects of embryonic and post-natal development, including maintenance of the mammalian female germline, are largely unknown. Here we employ a retrospective, phylogenetic-based method for reconstructing cell lineage trees utilizing somatic mutations accumulated in microsatellites, to study female germline dynamics in mice. Reconstructed cell lineage trees can be used to estimate lineage relationships between different cell types, as well as cell depth (number of cell divisions since the zygote). We show that, in the reconstructed mouse cell lineage trees, oocytes form clusters that are separate from hematopoietic and mesenchymal stem cells, both in young and old mice, indicating that these populations belong to distinct lineages. Furthermore, while cumulus cells sampled from different ovarian follicles are distinctly clustered on the reconstructed trees, oocytes from the left and right ovaries are not, suggesting a mixing of their progenitor pools. We also observed an increase in oocyte depth with mouse age, which can be explained either by depth-guided selection of oocytes for ovulation or by post-natal renewal. Overall, our study sheds light on substantial novel aspects of female germline preservation and development., Competing Interests: A patent on the cell lineage analysis method applied in this manuscript has been filed by Yeda Ltd, the licensing arm of the Weizmann Institute.

A systematic study of the amplified optical detection of DNA by Mg(2+)-dependent DNAzyme subunits is described. The use of two DNAzyme subunits and the respective fluorophore/quencher-modified substrate allows the detection of the target DNA with a sensitivity corresponding to 1 × 10(-9) M. The use of two functional hairpin structures that include the DNAzyme subunits in a caged, inactive configuration leads, in the presence of the target DNA, to the opening of one of the hairpins and to the activation of an autonomous cross-opening process of the two hairpins, which affords polymer DNA wires consisting of the Mg(2+)-dependent DNAzyme subunits. This amplification paradigm leads to the analysis of the target DNA with a sensitivity corresponding to 1 × 10(-14) M. The amplification mixture composed of the two hairpins can be implemented as a versatile sensing platform for analyzing any gene in the presence of the appropriate hairpin probe. This is exemplified with the detection of the BRCA1 oncogene.

Two engineered DNA nanostructures consisting of a nucleic acid functional hairpin and a DNA "tweezers" assembly act as pH-switchable devices for the "ON-OFF" activation/deactivation of the horseradish-peroxidase-mimicking DNAzyme., (This journal is © The Royal Society of Chemistry 2011)

Stem cell dynamics in vivo are often being studied by lineage tracing methods. Our laboratory has previously developed a retrospective method for reconstructing cell lineage trees from somatic mutations accumulated in microsatellites. This method was applied here to explore different aspects of stem cell dynamics in the mouse colon without the use of stem cell markers. We first demonstrated the reliability of our method for the study of stem cells by confirming previously established facts, and then we addressed open questions. Our findings confirmed that colon crypts are monoclonal and that, throughout adulthood, the process of monoclonal conversion plays a major role in the maintenance of crypts. The absence of immortal strand mechanism in crypts stem cells was validated by the age-dependent accumulation of microsatellite mutations. In addition, we confirmed the positive correlation between physical and lineage proximity of crypts, by showing that the colon is separated into small domains that share a common ancestor. We gained new data demonstrating that colon epithelium is clustered separately from hematopoietic and other cell types, indicating that the colon is constituted of few progenitors and ruling out significant renewal of colonic epithelium from hematopoietic cells during adulthood. Overall, our study demonstrates the reliability of cell lineage reconstruction for the study of stem cell dynamics, and it further addresses open questions in colon stem cells. In addition, this method can be applied to study stem cell dynamics in other systems., Competing Interests: The authors have declared that no competing interests exist.

The assembly of a "bipedal walker" and of a "bipedal stepper" using DNA constructs is described. These DNA machines are activated by H(+)/OH(-) and Hg(2+)/cysteine triggers. The bipedal walker is activated on a DNA template consisting of four nucleic acid footholds. The forward "walking" of the DNA on the template track is activated by Hg(2+) ions and H(+) ions, respectively, using the thymine-Hg(2+)-thymine complex or the i-motif structure as the DNA translocation driving forces. The backward "walking" is activated by OH(-) ions and cysteine, triggers that destroy the i-motif or thymine-Hg(2+)-thymine complexes. Similarly, the "bipedal stepper" is activated on a circular DNA template consisting of four tethered footholds. With the Hg(2+)/cysteine and H(+)/OH(-) triggers, clockwise or anticlockwise stepping is demonstrated. The operation of the DNA machines is followed optically by the appropriate labeling of the walker-foothold components with the respective fluorophores/quenchers units.