Hematuria and proteinuria in rheumatoid arthritis (RA) are commonly associated with drug therapy but occur independently of drugs, amyloid or urologic disorders. The latter occurrences suggest a primary renal lesion associated with RA. Review of reported renal biopsies identifies mesangial glomerulopathy as a common finding in RA patients without associated drug therapy and that it is frequently associated with hematuria in nonrheumatoid patients. Moreover, immunoglobulins have been shown to concentrate in the mesangium in experimental animals, suggesting that a functional response by the kidney mesangium to remove IgM rheumatoid factor (RF)-IgG complexes could lead to this mesangial lesion. We describe 3 patients with RA who had a mesangiopathy characterized by increased quantities of mesangial matrix and deposition of IgM without other lesions. Together, these observations suggest that: (1) mesangial glomerulopathy is common in RA; (2) removal of circulating RF-IgG complexes is a function of the mesangium and might produce this renal lesion; (3) mesangial glomerulopathy may be responsible for much of the hematuria observed in RA patients and, in many cases, may not be drug related and thus may not require discontinuing beneficial therapy.
The complexes of Ni2+, Cu2+, and Zn2+ with two closely related pendant-arm penta-aza macrocycles 11-(2′-dimethylaminoethyl)-1,4,7,11-tetra-azacyclotetradecane, L1, and 7-(2′-dimethylaminoethyl)-3,7,11,17-tetra-azabicyclo[11.3.1]heptadeca-1(17),13,15-triene, L2, have been characterised spectroscopically. The square-planar complex of the protonated ligand L1, [Ni(HL1)][ClO4]3, previously reported to be a mixture of two isomers, has been found to isomerise in hot aqueous solution to give two further isomers. Six-co-ordinate thiocyanato-complexes of formula [Ni(L1)(NCS)]ClO4 and [Ni(HL1)(NCS)2]ClO4 have been isolated. For the protonated copper(II) complex of the ligand (L1)(but not L2), a temperature-dependent equilibrium of the type [Cu(L1)]2++ H+⇌[Cu(HL1)]3+ exists in aqueous solution, and a variable-temperature visible spectroscopic study shows that, at 298.2 K, K=(2.2 ± 0.3)× 103 dm3 mol–1 and ΔG⊖=–19.05 ± 0.29 kJ mol–1. Isomerisation of the protonated copper complex was not observed. The complexes of formula [Zn(L)][NO3]2(L = L1 or L2) were found to be single isomers which do not isomerise even at elevated temperatures. 13C N.m.r. studies show that in [Zn(L1)][NO3]2 the macrocycle is asymmetric whereas in [Zn(L2)][NO3]2 the macrocycle is in a symmetric configuration. The new, related macrocycle, 11-methyl-1,4,7,11-tetra-azacyclotetradecane, L3, and its complexes with Ni2+, Cu2+, and Zn2+ have been prepared. 13C N.m.r. studies show that the diamagnetic, planar complex [Ni(L3)][ClO4]2 is a single symmetric species, whereas [Zn(L3)][NO3]2 is a 1 : 2 mixture of a symmetric and an asymmetric species.
Abstract Die l:1‐Komplexe von Pb‐nitrat mit den Liganden (Ia und b) wurden durch Reaktion des Pb‐Sa1‐ zes mit den festen Makrocyclen in DMSO dargestellt (Ausb. für den Komplex von (Ia) 89%) und in DMSO NMR‐spektroskopisch untersucht.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
In dimethyl sulphoxide (dmso) as solvent, the rate constant at 298·1 K for formation of the mono-complex of NiII ion with the unidentate ligand 4-phenylpyridine (kf= 1·64 × 103l mol–1 s–1) is ca. 24 and 63 times as large as corresponding values for the polydentate ligands 2,2′-bipyridine (bipy) and 2,2′,2″-terpyridine (terpy) respectively, and nearer to the solvent-exchange rate (kex= 7·4 × 103 s–1). These results are in marked contrast to values reported in aqueous solution where the rates of formation are about the same for py, bipy, and terpy, and a rate-determining chelate-ring-closure mechanism is postulated for the polydentate ligands in dmso. This postulate is supported by kinetic studies of the, HgII and H+ induced dissociations of the (2,2′-bipyridine)nickel(II) ion in dmso solution which indicate that, for 2,2′-bipyridine at 298·1 K, the rate of chelate-ring closure (rate constant krc) is ca. 60 times slower in dmso (krcca. 47 s–1) than in water (krcca. 3 × 103 s–1).
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