STRUCTURAL AND FUNCTIONAL STUDIES OF SYNAPTIC ENZYMES

Thimet oligopeptidase (TOP, EC 3.4.24.15) and neurolysin (EC 3.4.24.16) are zincdependent metallopeptidases that metabolize small bioactive peptides. The two enzymes share60 % sequence identity and their crystal structures demonstrate that they adopt nearly identicalfolds. They generally cleave at the same sites, but they recognize different positions on somepeptides, including neurotensin, a 13-residue peptide involved in modulation of dopaminergiccircuits, pain perception, and thermoregulation.On the basis of crystal structures and previous mapping studies, four residues(E469/R470, M490/R491, H495/N496, and R498/T499, TOP residues listed first) in thesubstrate-binding channel appear positioned to account for differences in specificity. TOPmutated to the neurolysin residues at all four position cleaves neurotensin at the neurolysin siteand neurolysin mutated to the TOP residues at all four sites cleaves at the TOP position. Using aseries of constructs mutated at only three sites, it was determined that only two of the mutations,E469/R470 and R498/T499, are required to swap the specificity of TOP and neurolysin. Theseresults were confirmed by testing the two mutation constructs, and either single mutant of TOPshown an intermediate specificity, cleaving at both sites.Crystal structures of the two mutation constructs of TOP and neurolysin unligandedforms, the mutations do not perturb local structure, but side chain conformations at theR498/T499 position differ from those of the mimicked enzyme. A model for differentialrecognition of neurotensin based on differences in surface charge distribution in the substratebinding sites is proposed. The model is supported by finding that reducing the positive charge onthe peptide results in cleavage at both hydrolysis sites.This dissertation also includes a description of the production and crystallization trials ofhuman neprilysin (E.C. 3.4.24.11), which will be used as another model system for studyingspecificity in metallopeptidases. In addition, the production and crystallization, and crystalcharacterization of human choline acetyltransferase (EC 2.3.1.6) is described

Chirality of Intermediate Filaments and Magnetic Helicity of Active Regions

Filaments which form either between or around active regions (ARs) are called intermediate filaments. In spite of various theoretical studies, the origin of the chirality of filaments is still uncovered. We investigated how intermediate filaments are related to their associated ARs, especially from the point of view of magnetic helicity and the orientation of polarity inversion lines (PILs). The chirality of filaments has been determined based on the orientations of barbs observed in BBSO full-disk Halpha images taken during the rising phase of solar cycle 23. The sign of magnetic helicity of ARs has been determined using S/inverse-S shaped sigmoids from Yohkoh SXT images. As a result, we have found a good correlation between the chirality of filaments and the magnetic helicity sign of ARs. Among 45 filaments, 42 filaments have shown the same sign as helicity sign of nearby ARs. It has been also confirmed that the role of both the orientation and the relative direction of PILs to ARs in determining the chirality of filaments is not significant, against a theoretical prediction. These results suggest that the chirality of intermediate filaments may originate from magnetic helicity of their associated ARs.Comment: 13 pages, 7 figures, Accepted for Ap

Radiomics signature on 3T dynamic contrast-enhanced magnetic resonance imaging for estrogen receptor-positive invasive breast cancers: Preliminary results for correlation with Oncotype DX recurrence scores

To evaluate the ability of a radiomics signature based on 3T dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to distinguish between low and non-low Oncotype DX (OD) risk groups in estrogen receptor (ER)-positive invasive breast cancers.Between May 2011 and March 2016, 67 women with ER-positive invasive breast cancer who performed preoperative 3T MRI and OD assay were included. We divided the patients into low (OD recurrence score [RS] <18) and non-low risk (RS ≥18) groups. Extracted radiomics features included 8 morphological, 76 histogram-based, and 72 higher-order texture features. A radiomics signature (Rad-score) was generated using the least absolute shrinkage and selection operator (LASSO). Univariate and multivariate logistic regression analyses were performed to investigate the association between clinicopathologic factors, MRI findings, and the Rad-score with OD risk groups, and the areas under the receiver operating characteristic curves (AUC) were used to assess classification performance of the Rad-score.The Rad-score was constructed for each tumor by extracting 10 (6.3%) from 158 radiomics features. A higher Rad-score (odds ratio [OR], 65.209; P <.001), Ki-67 expression (OR, 17.462; P = .007), and high p53 (OR = 8.449; P = .077) were associated with non-low OD risk. The Rad-score classified low and non-low OD risk with an AUC of 0.759.The Rad-score showed the potential for discrimination between low and non-low OD risk groups in patients with ER-positive invasive breast cancers. Copyright © 2019 the Author(s)

Age of first experience of gender incongruence among transgender and non-binary individuals

Objective Gender incongruence (GI) is a condition in which an individual’s gender identity, role, and expression differ from their assigned sex. This study aimed to evaluate when GI first arises in transgender and non-binary individuals seeking hormone therapy and their years living untreated in South Korea. Methods This retrospective study analyzed GI patients seeking gender-affirming hormone therapy (GAHT) or surgery between 2015 and 2021. The recorded data included gender identity, legal transition status, age of onset of GI, age at the initiation of therapy, and total therapy duration. Results In total, 337 patients were enrolled, including 149 (44.2%) transgender men, 153 (45.4%) transgender women, and 35 (10.4%) non-binary individuals. The mean age of onset of GI was 10.6 years (standard deviation, 5.1). Of the total patients, 29% had an onset of GI before age 6 years (preschool), 61% before age 12 (elementary-school), and 87% before age 15 (middle-school). Patients lived with GI for almost 14 years before GAHT initiation at a median age of 23.0 years. 90% of transgender men, 82.3% of transgender women, and 85% of non-binary patients disclosed their gender identities to their families. Regarding social transition, 31.5% of transgender men, 16.3% of transgender women, and none of the non-binary patients (P<0.005) changed their legal gender markers. Conclusion Many transgender and non-binary individuals experience GI early in life. These findings emphasized the need for early evaluation, timely gender-affirming care, and more accessible legal processes for gender marker changes in South Korea, aiming to enhance the safety and well-being of these individuals

Viable stretchable plasmonics based on unidirectional nanoprisms

Well-defined ordered arrays of plasmonic nanostructures were fabricated on stretchable substrates and tunable plasmon-coupling-based sensing properties were comprehensively demonstrated upon extension and contraction. Regular nanoprism patterns consisting of Ag, Au and Ag/Au bilayers were constructed on the stretchable polydimethylsiloxane substrate. The nanoprisms had the same orientation over the entire substrate (3 x 3 cm(2)) via metal deposition on a single-crystal microparticle monolayer assembly. The plasmonic sensor based on the Ag/Au bilayer showed a 6-fold enhanced surface enhanced Raman scattering signal under 20% uniaxial extension, whereas a 3-fold increase was observed upon 6% contraction, compared with the Au nanoprism arrays. The sensory behaviors were corroborated by finite-difference time-domain simulation, demonstrating the tunable electromagnetic field enhancement effect via the localized surface plasmon resonance coupling. The advanced flexible plasmonic-coupling-based devices with tunable and quantifiable performance herein suggested are expected to unlock promising potential in practical bio-sensing, biotechnological applications and optical devices.11Ysciescopu