Examining the role of patient-reported external factors and risk of relapse in anti-neutrophilic cytoplasmic autoantibody vasculitis

The role of stressors, insect bites, and infections on disease relapse of ANCA vasculitis has yet to be entirely explored, with limited retrospective studies focused on disease onset from small participant cohorts. Our study analyzes longitudinal survey data from 2011–2022 to evaluate this perspective from a large ANCA vasculitis cohort. We collected surveys every three to six months to obtain information on self-reported psychological stressors and significant life events, insect bites, and infections throughout clinical disease. We defined cohorts as those who relapsed (Relapse Cohort) and controls as those who did not relapse (Remission Cohort) during the study period. Survey responses were retrospectively reviewed during a 15-month timeframe prior to relapse or during 15 months of remission and categorized by type of stress event, insect bite, and infections at every available 3-month interval. There were no significant differences in stress and insect bites between the relapse and remission cohorts. Patients who relapsed reported more frequent upper respiratory infections and other infections, such as those affecting the skin and eyes, but there were no significant differences in the incidence of pulmonary or urinary infections compared to the remission cohort. There was a significant difference in reported upper respiratory infections 9 to 15 months prior to the relapse date, indicating a remote history of infections as a potentially significant physical stressor that may contribute to disease relapse. More frequent patient-reported infections, specifically upper respiratory infections, may contribute to patient vulnerability to relapse. Counseling and close monitoring of patients after infectious symptoms could aid in earlier detection of disease flares. Future studies are essential to further understand the importance of distal risk factors and how they impact relapse

Selenium-containing amino acids are targets for myeloperoxidase-derived hypothiocyanous acid: determination of absolute rate constants and implications for biological damage

Elevated MPO (myeloperoxidase) levels are associated with multiple human inflammatory pathologies. MPO catalyses the oxidation of Cl−, Br− and SCN− by H2O2 to generate the powerful oxidants hypochlorous acid (HOCl), hypobromous acid (HOBr) and hypothiocyanous acid (HOSCN) respectively. These species are antibacterial agents, but misplaced or excessive production is implicated in tissue damage at sites of inflammation. Unlike HOCl and HOBr, which react with multiple targets, HOSCN targets cysteine residues with considerable selectivity. In the light of this reactivity, we hypothesized that Sec (selenocysteine) residues should also be rapidly oxidized by HOSCN, as selenium atoms are better nucleophiles than sulfur. Such oxidation might inactivate critical Sec-containing cellular protective enzymes such as GPx (glutathione peroxidase) and TrxR (thioredoxin reductase). Stopped-flow kinetic studies indicate that seleno-compounds react rapidly with HOSCN with rate constants, k, in the range 2.8×103–5.8×106 M−1·s−1 (for selenomethionine and selenocystamine respectively). These values are ~6000-fold higher than the corresponding values for H2O2, and are also considerably larger than for the reaction of HOSCN with thiols (16-fold for cysteine and 80-fold for selenocystamine). Enzyme studies indicate that GPx and TrxR, but not glutathione reductase, are inactivated by HOSCN in a concentration-dependent manner; k for GPx has been determined as ~5×105 M−1·s−1. Decomposed HOSCN did not induce inactivation. These data indicate that selenocysteine residues are oxidized rapidly by HOSCN, with this resulting in the inhibition of the critical intracellular Sec-dependent protective enzymes GPx and TrxR

Preparation & Characterization of Some Organoplatinum(IV) Complexes Containing Pyridylpyrazoles

1019-102

Tertiary phosphines containing 2-thienyl group and their coordination chemistry

135-143Tertiary phosphines containing 2-thienyl group of the type PRnth3-n (R = Me, Et or Ph; th = 2-thienyl; n = 1 or 2) have been prepared and their coordination chemistry has been studied. Series of complexes of the types [PdCl2(PRnth3-n)2], [PdX2(PRnth3-n)2] (X = Cl, I, Me), [PdXY(PRnth3-n)2], (X = Cl; Y = Me or SnCl3), [PtMe(py) (PRnth3-n)2][PF6], [MCl(μ-Cl)(PR2th)]2 (M = Pd or Pt ), [PtCl2(CO)(PR2th)], [RhCl3(PEt2th)3] and [RhCl(CO) (PRnth3-n)2] have been synthesized with these phosphines and characterized by elemental analyses, IR, 1H, 31P, 119Sn, 195Pt NMR spectroscopy. In all the cases phosphine acts as a monodentate ligand with only phosphorus-metal coordination

Preparation and characterization of platinacycloalkanes containing nitrogen donor ligands

974-979Platinacycloalkanes of the type [PtX2(CH2)n(NN)] and [PtCl2(C3H5Me)(NN)] (where X = Cl, I; n = 3 or 4; NN = bis(1-pyrazolyl) methane, bis(3,5-dimethyl- l-pyrazolyl) methane, bis (2-pyridyl) methane and 2,2'-b ipyridyl) have been prepared and characterized by elemental analyses, IR, 1H and 13C NMR spectroscopy. The compounds [PtCl2(C3H5Me)(NN)] exist as mixtures of 2- and 3- methyl platinacyclobutane isomers. In solution these compounds possess an octahedral geometry in which halo groups occupy the axial positions

Synthesis of tertiary arsines containing N,N'-dimethylaminobenzyl group

983-985Tertiary arsines of the type [RAs(C6H4CH2NMe2)2] (R = Me, Et, Ph) and [Me2As(C6H4CH2NMe2)] have been prepared by the salt elimination reactions of Li[C6H4CH2NMe2)] with an appropriate organoarsenic (III) halide. These arsines have been characterized by elemental analysis, IR, mass and NMR (1H and 13C) spectral data

Synthesis and spectroscopic studies of di-<em>s</em>-and <em>t</em>-butyltin(IV) carboxylates

861-864Di-s- and t-butyltin(IV) carboxylates, [BuSn(OOCAr)2] (x = sec. or tert.; Ar = C6H5, C6H4OMe-2, 2-C4H3O, 2-C4H3S, 2-C5H4N, 2-C9H6N and 2-C4H3N2) have been prepared and characterized. Carboxylate moiety acts in a bidentate fashion either by coordination through both the oxygen atoms in an asymmetrical manner or chelating through nitrogen in case of ligands containing nitrogen heterocycles. Spectroscopic data (IR and NMR) suggest that these compounds adopt a six-coordinate configuration in solution

Synthesis and characterization of azaphosphole complexes of ruthenium and rhodium

506-512Reaction of azaphospholes (L) [2-phosphaindolizines (1) and 1,3-azaphospholo[5, 1-a]isoquinolines (2)] with [η5-Cp*RhCl2]2 (Cp* = pentamethylcyclopentadienyl) and [Ru(η6-cymene)Cl2]2 in 2:1 molar ratio in dichloromethane yields mononuclear complexes of the type [Cp*RhCl2(L)] .H2O and [Ru(cymene) Cl2(L)] .H2O. These complexes have been characterized by elemental analysis, FAB mass, IR and NMR (1H and 31P) spectral data. Stereochemistry of these complexes has been discussed based on NMR data. <span style="mso-bidi-font-weight: bold">NMR studies reveal a dynamic equilibrium between covalent and ionic forms of the complexes derived from 1 in solution. </span