An EGFR Targeted PET Imaging Probe for the Detection of Colonic Adenocarcinomas in the Setting of Colitis

Colorectal cancer is a serious complication associated with inflammatory bowel disease, often indistinguishable by screening with conventional FDG PET probes. We have developed an alternative EGFR-targeted PET imaging probe that may be used to overcome this difficulty, and successfully assessed its utility for neoplastic lesion detection in preclinical models. Cetuximab F(ab′)2 fragments were enzymatically generated, purified, and DOTA-conjugated. Radiolabeling was performed with 67Ga for cell based studies and 64Cu for in vivo imaging. Competitive binding studies were performed on CT26 cells to assess affinity (KD) and receptors per cell (Bmax). In vivo imaging using the EGFR targeted PET probe and 18F FDG was performed on CT26 tumor bearing mice in both control and dextran sodium sulfate (DSS) induced colitis settings. Spontaneous adenomas in genetically engineered mouse (GEM) models of colon cancer were additionally imaged. The EGFR imaging agent was generated with high purity (> 98%), with a labeling efficiency of 60 ± 5% and ≥99% radiochemical purity. The KD was 6.6 ± 0.7 nM and the Bmax for CT26 cells was 3.3 ± 0.1 × 106 receptors/cell. Target to background ratios (TBR) for CT26 tumors compared to colonic uptake demonstrated high values for both 18F-FDG (3.95 ± 0.13) and the developed 64Cu-DOTA-cetuximab-F(ab′)2 probe (4.42 ± 0.11) in control mice. The TBR for the EGFR targeted probe remained high (3.78 ± 0.06) in the setting of colitis, while for 18F FDG, this was markedly reduced (1.54 ± 0.08). Assessment of the EGFR targeted probe in the GEM models demonstrated a correlation between radiotracer uptake in spontaneous colonic lesions and the EGFR staining level ex vivo. A clinically translatable PET imaging probe was successfully developed to assess EGFR. The imaging agent can detect colonic tumors with a high TBR for detection of in situ lesions in the setting of colitis, and opens the possibility for a new approach for screening high-risk patients

Measuring vertebrate telomeres: applications and limitations

Telomeres are short tandem repeated sequences of DNA found at the ends of eukaryotic chromosomes that function in stabilizing chromosomal end integrity. In vivo studies of somatic tissue of mammals and birds have shown a correlation between telomere length and organismal age within species, and correlations between telomere shortening rate and lifespan among species. This result presents the tantalizing possibility that telomere length could be used to provide much needed information on age, ageing and survival in natural populations where longitudinal studies are lacking. Here we review methods available for measuring telomere length and discuss the potential uses and limitations of telomeres as age and ageing estimators in the fields of vertebrate ecology, evolution and conservation

Market Competition, Balanced Scorecard, and Their Effects on Hotel Organizational Performance and Manager's Satisfaction

This study examines the effect of market competition as a determinant of the balanced scorecard (BSC) system and the two consequences of organizational performance and managers' satisfaction. Four hypotheses are tested using partial least squares structural equation modeling. The data were collected from 145 valid responses from four- and five-star hotels in Turkey and focused on the pandemic period. The results revealed that market competition does not affect the use of BSC. Nevertheless, the BSC leads to better organizational performance and system satisfaction for managers. Managers' satisfaction with the BSC was also positively related to the performance of hotel organizations

The Strategic Performance Measurement System and Organisational Performance Through the Lenses of Contextual Factors: Empirical Evidence from the Hotel Industry

The unprecedented effects of COVID-19 have been problematic for hotels. Therefore, implementing a performance measurement system (PMS) has become critical for hotel organisations. This study thus examined how the balanced scorecard (BSC) as a strategic PMS has a function in revealing hotel performance. Two contextual factors of hotels-external environmental uncertainty (EEU) and decentralised decision-making-were also investigated to understand their effects on the use of the BSC, which, in turn, determines hotel performance. A survey was conducted involving 145 four- and five-star hotels in Turkey. Partial least squares structural equation modelling was used to test the hypotheses. It was found that EEU is significantly related to decentralised decision-making but not to the BSC. Meanwhile, the BSC does not have an indirect effect on the relationship between EEU and hotel performance; however, it was found to act as a mediator between the decentralisation of decision-making and hotel performance. Finally, decentralised decision-making was found to act as a mediator between EEU and the BSC

Loss of function of hNav1.5 by a ZASP1 mutation associated with intraventricular conduction disturbances in left ventricular noncompaction

BACKGROUND: Defects of cytoarchitectural proteins can cause left ventricular noncompaction, which is often associated with conduction system diseases. We have previously identified a p.D117N mutation in the LIM domain-binding protein 3-encoding Z-band alternatively spliced PDZ motif gene (ZASP) in a patient with left ventricular noncompaction and conduction disturbances. We sought to investigate the role of p.D117N mutation in the LBD3 NM_001080114.1 isoform (ZASP1-D117N) for the regulation of cardiac sodium channel (Na(v)1.5) that plays an important role in the cardiac conduction system. METHODS AND RESULTS: Effects of ZASP1-wild-type and ZASP1-D117N on Na(v)1.5 were studied in human embryonic kidney-293 cells and neonatal rat cardiomyocytes. Patch-clamp study demonstrated that ZASP1-D117N significantly attenuated I(Na) by 27% in human embryonic kidney-293 cells and by 32% in neonatal rat cardiomyocytes. In addition, ZASP1-D117N rightward shifted the voltage-dependent activation and inactivation in both systems. In silico simulation using Luo-Rudy phase 1 model demonstrated that altered Na(v)1.5 function can reduce cardiac conduction velocity by 28% compared with control. Pull-down assays showed that both wild-type and ZASP1-D117N can complex with Na(v)1.5 and telethonin/T-Cap, which required intact PDZ domains. Immunohistochemical staining in neonatal rat cardiomyocytes demonstrates that ZASP1-D117N did not significantly disturb the Z-line structure. Disruption of cytoskeletal networks with 5-iodonaphthalene-1-sulfonyl homopiperazine and cytochalasin D abolished the effects of ZASP1-D117N on Na(v)1.5. CONCLUSIONS: ZASP1 can form protein complex with telethonin/T-Cap and Na(v)1.5. The left ventricular noncompaction-specific ZASP1 mutation can cause loss of function of Na(v)1.5, without significant alteration of the cytoskeletal protein complex. Our study suggests that electric remodeling can occur in left ventricular noncompaction subject because of a direct effect of mutant ZASP on Na(v)1.5

Portable Microfluidic Integrated Plasmonic Platform for Pathogen Detection

Timely detection of infectious agents is critical in early diagnosis and treatment of infectious diseases. Conventional pathogen detection methods, such as enzyme linked immunosorbent assay (ELISA), culturing or polymerase chain reaction (PCR) require long assay times, and complex and expensive instruments, which are not adaptable to point-of-care (POC) needs at resource-constrained as well as primary care settings. Therefore, there is an unmet need to develop simple, rapid, and accurate methods for detection of pathogens at the POC. Here, we present a portable, multiplex, inexpensive microfluidic-integrated surface plasmon resonance (SPR) platform that detects and quantifies bacteria, i.e., Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) rapidly. The platform presented reliable capture and detection of E. coli at concentrations ranging from ∼105 to 3.2 × 107 CFUs/mL in phosphate buffered saline (PBS) and peritoneal dialysis (PD) fluid. The multiplexing and specificity capability of the platform was also tested with S. aureus samples. The presented platform technology could potentially be applicable to capture and detect other pathogens at the POC and primary care settings. © 2015, Nature Publishing Group. All rights reserved

VEZF1 elements mediate protection from DNA methylation

There is growing consensus that genome organization and long-range gene regulation involves partitioning of the genome into domains of distinct epigenetic chromatin states. Chromatin insulator or barrier elements are key components of these processes as they can establish boundaries between chromatin states. The ability of elements such as the paradigm β-globin HS4 insulator to block the range of enhancers or the spread of repressive histone modifications is well established. Here we have addressed the hypothesis that a barrier element in vertebrates should be capable of defending a gene from silencing by DNA methylation. Using an established stable reporter gene system, we find that HS4 acts specifically to protect a gene promoter from de novo DNA methylation. Notably, protection from methylation can occur in the absence of histone acetylation or transcription. There is a division of labor at HS4; the sequences that mediate protection from methylation are separable from those that mediate CTCF-dependent enhancer blocking and USF-dependent histone modification recruitment. The zinc finger protein VEZF1 was purified as the factor that specifically interacts with the methylation protection elements. VEZF1 is a candidate CpG island protection factor as the G-rich sequences bound by VEZF1 are frequently found at CpG island promoters. Indeed, we show that VEZF1 elements are sufficient to mediate demethylation and protection of the APRT CpG island promoter from DNA methylation. We propose that many barrier elements in vertebrates will prevent DNA methylation in addition to blocking the propagation of repressive histone modifications, as either process is sufficient to direct the establishment of an epigenetically stable silent chromatin stat

Epigenetic memory in induced pluripotent stem cells

Somatic cell nuclear transfer and transcription-factor-based reprogramming revert adult cells to an embryonic state, and yield pluripotent stem cells that can generate all tissues. Through different mechanisms and kinetics, these two reprogramming methods reset genomic methylation, an epigenetic modification of DNA that influences gene expression, leading us to hypothesize that the resulting pluripotent stem cells might have different properties. Here we observe that low-passage induced pluripotent stem cells (iPSCs) derived by factor-based reprogramming of adult murine tissues harbour residual DNA methylation signatures characteristic of their somatic tissue of origin, which favours their differentiation along lineages related to the donor cell, while restricting alternative cell fates. Such an ‘epigenetic memory’ of the donor tissue could be reset by differentiation and serial reprogramming, or by treatment of iPSCs with chromatin-modifying drugs. In contrast, the differentiation and methylation of nuclear-transfer-derived pluripotent stem cells were more similar to classical embryonic stem cells than were iPSCs. Our data indicate that nuclear transfer is more effective at establishing the ground state of pluripotency than factor-based reprogramming, which can leave an epigenetic memory of the tissue of origin that may influence efforts at directed differentiation for applications in disease modelling or treatment.National Institutes of Health (U.S.) (NIH grant RO1-DK70055)National Institutes of Health (U.S.) (NIH Grant RO1-DK59279)National Institutes of Health (U.S.) (American Recovery and Reinvestment Act (RC2-HL102815))National Institutes of Health (U.S.) (NIH (K99HL093212-01))Cooley’s Anemia FoundationNational Institutes of Health (U.S.) (NIH LLS (3567-07))National Institutes of Health (U.S.) (NIH grant R37CA054358)National Institutes of Health (U.S.) (NIH grant P50HG003233)National Institutes of Health (U.S.) (NIH grant R01AI047457)National Institutes of Health (U.S.) (NIH Grant R01AI047458)National Institutes of Health (U.S.) (CA86065)National Institutes of Health (U.S.) (HL099999)Thomas and Stacey Siebel FoundationCalifornia Institute for Regenerative Medicine (Fellowship T1-00001