Synthesis and characterization of oligonucleotides containing 2′-fluorinated thymidine glycol as inhibitors of the endonuclease III reaction

Endonuclease III (Endo III) is a base excision repair enzyme that recognizes oxidized pyrimidine bases including thymine glycol. This enzyme is a glycosylase/lyase and forms a Schiff base-type intermediate with the substrate after the damaged base is removed. To investigate the mechanism of its substrate recognition by X-ray crystallography, we have synthesized oligonucleotides containing 2′-fluorothymidine glycol, expecting that the electron-withdrawing fluorine atom at the 2′ position would stabilize the covalent intermediate, as observed for T4 endonuclease V (Endo V) in our previous study. Oxidation of 5′- and 3′-protected 2′-fluorothymidine with OsO(4) produced two isomers of thymine glycol. Their configurations were determined by NMR spectroscopy after protection of the hydroxyl functions. The ratio of (5R,6S) and (5S,6R) isomers was 3:1, whereas this ratio was 6:1 in the case of the unmodified sugar. Both of the thymidine glycol isomers were converted to the corresponding phosphoramidite building blocks and were incorporated into oligonucleotides. When the duplexes containing 2′-fluorinated 5R- or 5S-thymidine glycol were treated with Escherichia coli endo III, no stabilized covalent intermediate was observed regardless of the stereochemistry at C5. The 5S isomer was found to form an enzyme–DNA complex, but the incision was inhibited probably by the fluorine-induced stabilization of the glycosidic bond

Longitudinal observation of insulin secretory ability before and after the onset of immune checkpoint inhibitor-induced diabetes mellitus: A report of two cases

Immune checkpoint inhibitor-induced diabetes mellitus is a rare immune-related adverse event. This report illustrates clinical data and insulin secretory ability before and after the onset of immune checkpoint inhibitor-induced diabetes

Chemical synthesis of oligodeoxyribonucleotides containing the Dewar valence isomer of the (6–4) photoproduct and their use in (6–4) photolyase studies

The pyrimidine(6–4)pyrimidone photoproduct, a major UV lesion formed between adjacent pyrimidine bases, is transformed to its Dewar valence isomer upon exposure to UVA/UVB light. We have synthesized a phosphoramidite building block of the Dewar photoproduct formed at the thymidylyl(3′–5′)thymidine site and incorporated it into oligodeoxyribonucleotides. The diastereoisomers of the partially protected dinucleoside monophosphate bearing the (6–4) photoproduct, which were caused by the chirality of the phosphorus atom, were separated by reversed-phase chromatography, and the (6–4) photoproduct was converted to the Dewar photoproduct by irradiation of each isomer with Pyrex-filtered light from a high-pressure mercury lamp. The Dewar photoproduct was stable under both acidic and alkaline conditions at room temperature. After characterization of the isomerized base moiety by NMR spectroscopy, a phosphoramidite building block was synthesized in three steps. Although the ordinary method could be used for the oligonucleotide synthesis, benzimidazolium triflate as an alternative activator yielded better results. The oligonucleotides were used for the analysis of the reaction and the binding of Xenopus (6–4) photolyase. Although the affinity of this enzyme for the Dewar photoproduct-containing duplex was reportedly similar to that for the (6–4) photoproduct-containing substrate, the results suggested a difference in the binding mode

Expression of Long-form N-Acetylglucosamine-6-O-Sulfotransferase 1 in Human High Endothelial Venules

Two members of the N-acetylglucosamine-6-O-sulfotransferase (GlcNAc6ST) family, GlcNAc6ST-1 and GlcNAc6ST-2, function in the biosynthesis of 6-sulfo sialyl Lewis X-capped glycoproteins expressed on high endothelial venules (HEVs) in secondary lymphoid organs. Thus, both enzymes play a critical role in L-selectin-expressing lymphocyte homing. Human GlcNAc6ST-1 is encoded by a 1593-bp open reading frame exhibiting two 5' in-frame methionine codons spaced 141 bp apart. Both resemble the consensus sequence for translation initiation. Thus, it has been hypothesized that both long and short forms of GlcNAc6ST-1 may be present, although endogenous expression of either form has not been confirmed in humans. Here, the authors developed an antibody recognizing amino acid residues between the first two human GlcNAc6ST-1 methionines. This antibody specifically recognizes the long form of the enzyme, a finding validated by Western blot analysis and immunofluorescence cytochemistry of HeLa cells misexpressing long and/or short forms of human GlcNAc6ST-1. Using this antibody, the authors carried out immunofluorescence histochemistry of human lymph node tissue sections and found endogenous expression of the long form of the enzyme in human tissue, predominantly in the trans-Golgi network of endothelial cells that form HEVs. (J Histochem Cytochem 60:397-407, 2012)ArticleJOURNAL OF HISTOCHEMISTRY & CYTOCHEMISTRY. 60(5):397-407 (2012)journal articl

Changes in the Corneal Endothelium of Aphakic Patients Following Extended Soft Contact Lens Wear

The contact lenses used for visual correction of aphakia are mostly soft contact lenses for extended wear because most aphakic patients are elderly. The effects of extended wear of such contact lenses on corneal endothelial cells have been recently reported. In this study, two groups, an extended wear SCL group and a spectacles group, were compared with respect to various parameters by means of specular microscopy following surgery for cataract. The SCL group consisted of 16 subjects and 16 eyes. The average age at operation was 67.8 years and the wearing period was 1 to 5 years after operation. The spectacles group consisted of 14 subjects and 16 eyes; the average age at operation was 70.1 years, and the wearing period was 1 to 5 years after surgery. Using a wide field specular microscope (mode1 SP-1), endothelial cells in the central part of the cornea were observed and photographed. The endothelial cell picture was then enlarged to a final magnification of 450 times, and the image was analyzed using the KC-8VA cell analyzer system. There was no significant difference in the mean cell area (μm2) and mean cell density (cell counts/mm2) between the two groups, but the coefficient of variation (CV) was significantly elevated in the SCL group after operation. The percentage of hexagonal cells was also significantly lower in the SCL group after operation. Therefore extended wear of soft contact lenses appears to make corneal endothelial cells unstable and accelerates changes in cornet endothelial cells due to aging

Characterization of a Y-Family DNA Polymerase eta from the Eukaryotic Thermophile Alvinella pompejana

Human DNA polymerase η (HsPolη) plays an important role in translesion synthesis (TLS), which allows for replication past DNA damage such as UV-induced cis-syn cyclobutane pyrimidine dimers (CPDs). Here, we characterized ApPolη from the thermophilic worm Alvinella pompejana, which inhabits deep-sea hydrothermal vent chimneys. ApPolη shares sequence homology with HsPolη and contains domains for binding ubiquitin and proliferating cell nuclear antigen. Sun-induced UV does not penetrate Alvinella's environment; however, this novel DNA polymerase catalyzed efficient and accurate TLS past CPD, as well as 7,8-dihydro-8-oxoguanine and isomers of thymine glycol induced by reactive oxygen species. In addition, we found that ApPolη is more thermostable than HsPolη, as expected from its habitat temperature. Moreover, the activity of this enzyme was retained in the presence of a higher concentration of organic solvents. Therefore, ApPolη provides a robust, human-like Polη that is more active after exposure to high temperatures and organic solvents

Harada\u27s Disease (Vogt-Koyanagi-Harada Syndrome; VKH Syndrome)

We studied the course and outcome of 44 patients with Harada\u27s disease (17 males and 27 females) who were treated in the Department of Ophthalmology of Kawasaki Hospital, an affiliated hospital of Kawasaki Medical School, between April 1980 and March 1990. The age at onset ranged from 14 to 77 years with the mean age±SD being 46.5 ± 15.6 years. Thus the disease was frequent among the elderly. The posterior and optic types of the disease were most frequently found in our patients. As extraocular symptoms, perceptive deafness and an increase in the cell count of the cerebrospinal fluid were frequently observed, and these were important factors in the diagnosis of the disease. Systemic administration of steroids was the main treatment, with immunosuppressive agents being administereted to patiens with the delayed type of the disease. As for the visual prognosis, the final corrected visual acuity was 1.0 in 79% of the patients. As eye complications, cataracts and glaucoma were frequently noted, and various other lesions of the fundus were also observed with increasing age. Patients with the delayed type of the disease accounted for 34.1% of the patients studied

A Novel CLEIA for FGF23

Introduction: Measurement of fibroblast growth factor 23 (FGF23) has been reported to be clinically useful for the differential diagnosis of chronic hypophosphatemia. However, assays for research use only are available in Japan. Thus, the objective of this study was to examine the clinical utility of a novel and automated chemiluminescent enzyme immunoassay for the measurement of FGF23. Materials and Methods: Participants were recruited from July 2015 to January 2017 at six facilities in Japan. Thirty-eight patients with X-linked hypophosphatemic rickets (XLH; 15 males, 23 females, age 0–66 years), five patients with tumour-induced osteomalacia (TIO; 3 males, 2 females, age 60–73 years), and twenty-two patients with hypophosphatemia (11 males, 11 females, age 1–75 years) caused due to other factors participated in this study. Results: With the clinical cut-off value of FGF23 at 30.0 pg/mL indicated in the Diagnostic Guideline of Rickets/Osteomalacia in Japan, the sensitivity and specificity of FGF23-related hypophosphatemic rickets/osteomalacia without vitamin D deficiency (disease group-1) were 100% and 81.8%, respectively, which distinguished it from non-FGF23-related hypophosphatemia (disease group-2). Furthermore, the diagnostic sensitivity of FGF23-related hypophosphatemia with vitamin D deficiency remained at 100%. Among the four patients with FGF23 levels ≥ 30.0 pg/mL in disease group-2, two patients with relatively higher FGF23 values were suspected to have genuine FGF23-related hypophosphatemia, due to the ectopic production of FGF23 in pulmonary and prostate small cell carcinomas. Conclusion: The novel FGF23 assay tested in this study is useful for the differential diagnosis of hypophosphatemic rickets/osteomalacia in a clinical setting