Fabrication and evaluation of bilateral Helmholtz radiofrequency coil for thermo-stable breast image with reduced artifacts

PURPOSE: The positron emission tomography (PET)-magnetic resonance (MR) system is a newly emerging technique that yields hybrid images with high-resolution anatomical and metabolic information. With PET-MR imaging, a definitive diagnosis of breast abnormalities will be possible with high spatial accuracy and images will be acquired for the optimal fusion of anatomic locations. Therefore, we propose a PET-compatible two-channel breast MR coil with minimal disturbance to image acquisition which can be used for simultaneous PET-MR imaging in patients with breast cancer. MATERIALS AND METHODS: For coil design and construction, the conductor loops of the Helmholtz coil were tuned, matched, and subdivided with nonmagnetic components. Element values were optimized with an electromagnetic field simulation. Images were acquired on a GE 600 PET-computed tomography (CT) and GE 3.0 T MR system. For this study, we used the T1-weighted image (volunteer; repetition time (TR), 694 ms; echo time (TE), 9.6 ms) and T2-weighted image (phantom; TR, 8742 ms; TE, 104 ms) with the fast spin-echo sequence. RESULTS: The results of measuring image factors with the proposed radiofrequency (RF) coil and standard conventional RF coil were as follows: signal-to-noise ratio (breast; 207.7 vs. 175.2), percent image uniformity (phantom; 89.22%-91.27% vs. 94.63%-94.77%), and Hounsfield units (phantom; -4.51 vs. 2.38). CONCLUSIONS: Our study focused on the feasibility of proposed two-channel Helmholtz loops (by minimizing metallic components and soldering) for PET-MR imaging and found the comparable image quality to the standard conventional coil. We believe our work will help significantly to improve image quality with the development of a less metallic breast MR coil

O-GlcNAc modulation at Akt1 Ser473 correlates with apoptosis of murine pancreatic β cells

O-GlcNAc transferase (OGT)-mediated modification of protein Ser/Thr residues withO-GlcNAc influences protein activity, similar to the effects of phosphorylation. The anti-apoptotic Akt1 is both activated by phosphorylation and modified with O-GlcNAc. However, the nature and significance of the Akt1 O-GlcNAc modification is unknown. The relationship of O-GlcNAc modification and phosphorylation at Akt1 Ser473 was examined with respect to apoptosis of murine β-pancreatic cells. Glucosamine treatment induced apoptosis, which correlated with enhanced O-GlcNAc modification of Akt1 and concomitant reduction in Ser473 phosphorylation. Pharmacological inhibition of OGT or O-GlcNAcase revealed an inverse correlation between O-GlcNAcmodification and Ser473 phosphorylation of Akt1. MALDI-TOF/TOFmass spectrometry analysis of Akt1 immunoprecipitates fromglucosamine-treated cells, but not untreated controls, showed a peptide containing S473/T479 that was presumably modified withO-GlcNAc. Furthermore, in vitroO-GlcNAc-modification analysis of wildtype and mutant Akt1 revealed that S473 was targeted by recombinant OGT. A S473A Akt1 mutant demonstrated reduced basal and glucosamine-induced Akt1 O-GlcNAc modification compared with wildtype Akt1. Furthermore, wildtype Akt1, but not the S473A mutant, appeared to be associated with OGT following glucosamine treatment. Together, these observations suggest that Akt1 Ser473 may undergo both phosphorylation and O-GlcNAc modification, and the balance between these may regulatemurine β-pancreatic cell fate

A Case of Anaphylaxis After the Ingestion of Yacon

Anaphylaxis is a potentially life-threatening systemic allergic reaction, often with an explosive onset; the symptoms range from mild flushing to upper respiratory obstruction, with or without vascular collapse. Foods are common offending allergens and remain the leading cause of outpatient anaphylaxis in most surveys. Yacon (Smallanthus sonchifolius) is a plant native to the Andes region, where its root is cultivated and consumed mainly as food. Unlike most edible roots, yacon contains large amounts of ructooligosaccharides. Traditionally, yacon tubers have been used as a source of natural sweetener and syrup for people suffering from various disorders. We report the case of a 55-year-old woman who developed syncope and generalized urticaria after ingesting yacon roots. The patient had positive skin prick and intradermal tests to yacon extract. An open food challenge test was performed to confirm food anaphylaxis and was positive 10 minutes after the consumption of yacon roots. To our knowledge, this is the first reported case of anaphylaxis after the ingestion of yacon roots

Korea HIV/AIDS Cohort Study: study design and baseline characteristics

The number of persons infected by HIV/AIDS has consistently increased in Korea since the first case of HIV/AIDS infection in 1985 and reached 15,208 by 2016. About 1,100 new patients with HIV/ AIDS infections have emerged every year since 2013. In Korea, the Korea HIV/AIDS Cohort Study was established for the evidenced-based prevention, treatment, and effective management of patients infected with human immunodeficiency virus (HIV) in December 2006. This study monitored 1,438 patients, who accounted for about 10% of all patients with HIV/AIDS in Korea, for 10 years with the following aims: (1) to develop an administrative system for the establishment of a HIV/AIDS cohort-based study; (2) to standardize methodologies and the case report forms; and (3) to standardize multi-cohort data and develop a data cleaning method. This study aims to monitor at least 1,000 patients (excluding those for whom investigation had been completed) per year (estimated number of patients who can be monitored by January 2018: 939). By December 2016, the sex distribution was 93.3% for men, and 6.7% for women (gender ratio, 13.9:1.0), and 98.9% of all participants were Korean. More than 50.0% of the participants were confirmed as HIV positive after 2006. This study reports competitive, long-term research that aimed to develop policies for the prevention of chronic infectious diseases for patients with HIV. The data collected over the last decade will be used to develop indices for HIV treatment and health promotion

Regulation of BRCA1 stability through the tandem UBX domains of isoleucyl-tRNA synthetase 1

Aminoacyl-tRNA synthetases possess unique domains. In this study the structure of the vertebrate IARS1 and EARS1 complex reveals that vertebrate IARS1 protects the DNA repair factor BRCA1 from proteolytic degradation via its UBX-fold domain. Aminoacyl-tRNA synthetases (ARSs) have evolved to acquire various additional domains. These domains allow ARSs to communicate with other cellular proteins in order to promote non-translational functions. Vertebrate cytoplasmic isoleucyl-tRNA synthetases (IARS1s) have an uncharacterized unique domain, UNE-I. Here, we present the crystal structure of the chicken IARS1 UNE-I complexed with glutamyl-tRNA synthetase 1 (EARS1). UNE-I consists of tandem ubiquitin regulatory X (UBX) domains that interact with a distinct hairpin loop on EARS1 and protect its neighboring proteins in the multi-synthetase complex from degradation. Phosphomimetic mutation of the two serine residues in the hairpin loop releases IARS1 from the complex. IARS1 interacts with BRCA1 in the nucleus, regulates its stability by inhibiting ubiquitylation via the UBX domains, and controls DNA repair function

Raman spectroscopy: techniques and applications in the life sciences

Raman spectroscopy is an increasingly popular technique in many areas including biology and medicine. It is based on Raman scattering, a phenomenon in which incident photons lose or gain energy via interactions with vibrating molecules in a sample. These energy shifts can be used to obtain information regarding molecular composition of the sample with very high accuracy. Applications of Raman spectroscopy in the life sciences have included quantification of biomolecules, hyperspectral molecular imaging of cells and tissue, medical diagnosis, and others. This review briefly presents the physical origin of Raman scattering explaining the key classical and quantum mechanical concepts. Variations of the Raman effect will also be considered, including resonance, coherent, and enhanced Raman scattering. We discuss the molecular origins of prominent bands often found in the Raman spectra of biological samples. Finally, we examine several variations of Raman spectroscopy techniques in practice, looking at their applications, strengths, and challenges. This review is intended to be a starting resource for scientists new to Raman spectroscopy, providing theoretical background and practical examples as the foundation for further study and exploration

Molecular diagnosis of hereditary spherocytosis by multi-gene target sequencing in Korea: matching with osmotic fragility test and presence of spherocyte

Background Current diagnostic tests for hereditary spherocytosis (HS) focus on the detection of hemolysis or indirectly assessing defects of membrane protein, whereas direct methods to detect protein defects are complicated and difficult to implement. In the present study, we investigated the patterns of genetic variation associated with HS among patients clinically diagnosed with HS. Methods Multi-gene targeted sequencing of 43 genes (17 RBC membrane protein-encoding genes, 20 RBC enzyme-encoding genes, and six additional genes for the differential diagnosis) was performed using the Illumina HiSeq platform. Results Among 59 patients with HS, 50 (84.7%) had one or more significant variants in a RBC membrane protein-encoding genes. A total of 54 significant variants including 46 novel mutations were detected in six RBC membrane protein-encoding genes, with the highest number of variants found in SPTB (n = 28), and followed by ANK1 (n = 19), SLC4A1 (n = 3), SPTA1 (n = 2), EPB41 (n = 1), and EPB42 (n = 1). Concurrent mutations of genes encoding RBC enzymes (ALDOB, GAPDH, and GSR) were detected in three patients. UGT1A1 mutations were present in 24 patients (40.7%). Positive rate of osmotic fragility test was 86.8% among patients harboring HS-related gene mutations. Conclusions This constitutes the first large-scaled genetic study of Korean patients with HS. We demonstrated that multi-gene target sequencing is sensitive and feasible that can be used as a powerful tool for diagnosing HS. Considering the discrepancies of clinical and molecular diagnoses of HS, our findings suggest that molecular genetic analysis is required for accurate diagnosis of HS.Support was provided by: the National Research Foundation of Korea (NRF) grant funded by the Korea government(MSIT) (NRF-2017R1A2A1A17069780) http://www.nrf.re.kr/

Angiogenic Effects of Collagen/Mesoporous Nanoparticle Composite Scaffold Delivering VEGF165

Vascularization is a key issue for the success of tissue engineering to repair damaged tissue. In this study, we report a composite scaffold delivering angiogenic factor for this purpose. Vascular endothelial growth factor (VEGF) was loaded on mesoporous silica nanoparticle (MSN), which was then incorporated within a type I collagen sponge, to produce collagen/MSN/VEGF (CMV) scaffold. The CMV composite scaffold could release VEGF sustainably over the test period of 28 days. The release of VEGF improved the cell proliferation. Moreover, the in vivo angiogenesis of the scaffold, as studied by the chick chorioallantoic membrane (CAM) model, showed that the VEGF-releasing scaffold induced significantly increased number of blood vessel complexes when compared with VEGF-free scaffold. The composite scaffold showed good biocompatibility, as examined in rat subcutaneous tissue. These results demonstrate that the CMV scaffold with VEGF-releasing capacity can be potentially used to stimulate angiogenesis and tissue repair

Dynamic Mechanical and Nanofibrous Topological Combinatory Cues Designed for Periodontal Ligament Engineering.

Complete reconstruction of damaged periodontal pockets, particularly regeneration of periodontal ligament (PDL) has been a significant challenge in dentistry. Tissue engineering approach utilizing PDL stem cells and scaffolding matrices offers great opportunity to this, and applying physical and mechanical cues mimicking native tissue conditions are of special importance. Here we approach to regenerate periodontal tissues by engineering PDL cells supported on a nanofibrous scaffold under a mechanical-stressed condition. PDL stem cells isolated from rats were seeded on an electrospun polycaprolactone/gelatin directionally-oriented nanofiber membrane and dynamic mechanical stress was applied to the cell/nanofiber construct, providing nanotopological and mechanical combined cues. Cells recognized the nanofiber orientation, aligning in parallel, and the mechanical stress increased the cell alignment. Importantly, the cells cultured on the oriented nanofiber combined with the mechanical stress produced significantly stimulated PDL specific markers, including periostin and tenascin with simultaneous down-regulation of osteogenesis, demonstrating the roles of topological and mechanical cues in altering phenotypic change in PDL cells. Tissue compatibility of the tissue-engineered constructs was confirmed in rat subcutaneous sites. Furthermore, in vivo regeneration of PDL and alveolar bone tissues was examined under the rat premaxillary periodontal defect models. The cell/nanofiber constructs engineered under mechanical stress showed sound integration into tissue defects and the regenerated bone volume and area were significantly improved. This study provides an effective tissue engineering approach for periodontal regeneration-culturing PDL stem cells with combinatory cues of oriented nanotopology and dynamic mechanical stretch