Purpose: We have extended our previous observation that the percent occurrence of calcium oxalate stones decreased while that of calcium phosphate stones increased with each new stone event.Materials and Methods: The National VA Crystal Identification Center has analyzed veteran patient urinary tract stones from VA hospitals throughout the United States since 1983. We reviewed the composition of 33,198 stones with emphasis on the changes in composition. More than 11,786 stones came from 5,088 recurrent stone formers. Stones were analyzed using high resolution x-ray powder diffraction and Fourier transform infrared spectroscopic techniques. When the stones were investigated as a function of time, it was determined that there was greater variability when samples were more than 30 days apart.Results: The percent occurrence of whewellite, weddelite, apatite, brushite and uric acid in stones increased between 1.0% and 5.9% since our previous study, The percent occurrence of struvite decreased by 2.6%. The percent of calcium oxalate stones decreased while that of calcium phosphate stones increased with each new event. However, the total percent occurrence of all calcium containing stones did not significantly change with recurrent stone events.Conclusions: Our study suggests a strong trend for the conversion of stone disease from calcium oxalate to calcium phosphate containing stones, which could influence the progression and severity of disease.

Background: The interaction between kidney urothelium and crystals is a critical event in the growth of renal calculi. When studying calcium oxalate monohydrate (COM) crystal binding to Madin-Darby canine kidney (MDCK) cells in culture, we observed that crystals also attached to areas on the coverslips devoid of cells. This phenomenon could be the result of substances produced by the cells that adhere to the glass and subsequently bind COM crystals. We investigated the characteristics of this COM binding substance.Methods: Media was collected from cultures of MDCK cells (conditioned media) and proteins were separated by high performance liquid chromatography. The molecular weights and purity of isolated proteins were determined by polyacrylamide gel electrophoresis. The conditioned media and each separated fraction were applied to glass and to MDCK cells and COM-binding ability determined using C-14-labeled crystals. The binding of radio-labelled calcium oxalate dihydrate, brushite, uric acid, and apatite to coverslips were also studied.Results: Fourteen times more COM bound to coverslips incubated with conditioned media than those with control media. The molecular weight of the protein bound to the glass was determined to be 200 kDa. The COM crystals binding to this protein was 1.5 mug/ng. Other crystals bound to a lesser extent. The incubation of cells with this protein inhibited COM binding by 39%.Conclusion: The MDCK cells produce a 200-kDa protein that has a high binding affinity for COM crystals. This protein binds to glass and is responsible for crystal binding to areas devoid of cells. This protein also has an inhibitory effect on COM binding to MDCK cells in culture.

The chemistry and molecular bonding characteristics of the CaPPi family of compounds are very complex. The unique molecular flexibility of the PPi anion and the potential variability of Ca coordination geometries have allowed for a broad spectrum of CaPPi type structures. The structure of t-CPPD has the smallest P-OB-P angle of the known CaPPi structures, both Ca atoms are 7 coordinate which is the maximum allowable contacts for Ca atoms, and the two water molecules of crystallization not only serve to fill molecular space, but they are also involved in direct contact to the PPi anions and the Ca atoms. The structure of t-CPPD appears to be very stable and the structural characteristics support the observation that the crystals are sparingly soluble in an aqueous environment. Unfortunately, the structure of m-CPPD is not known and comparisons cannot be made. The solution model studies have resulted in the observation that t-CPPD and m-CPPD crystals can be grown in an aqueous environment at conditions far less harsh than those required for the standard synthetic procedure. However, the synthetic procedure, in contrast to the solution models, yields the prismatic crystal growth morphology of t-CPPD and the rod morphology of m-CPPD observed in vivo. The solution models showed that increasing Mg or Pi retarded crystal formation. At physiologic levels of Mg and Pi, a-CaPPi formed, but neither t-CPPD nor m-CPPD would form. In all solution studies, the final Ca and PPi were not determined and therefore a correlation could not be made between the ionic concentrations and crystal type formed. The gel models using silica, polyacrylamide, and biologic grade gelatin all highlighted that the time of incubation of Ca and PPi ions was a critical parameter in determining the type of crystal formed. The biologic grade gelatin model studies that we conducted indicated that the formation of the two in vivo crystals was mediated by the formation of intermediate crystalline materials and the subsequent dissolution of those species. This formation/dissolution/reformation mechanism allows for a very localized ionic concentrating process to occur. In our model system, we measured the final Ca and PPi levels at all points of crystallization and could map the ionic concentration gradients and compare them to the crystal type formed with respect to the time of incubation. However, the crystal growth morphologies for t-CPPD and m-CPPD still did not match the morphologies observed in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)

Crystalline hydroxyapatite is a component of bone, teeth, and numerous pathological calcifications. The apatite crystal structure can accommodate a wide variety of atomic substitutions which gives apatite crystals an unusually high degree of variability in biochemical and physical properties. Apatite crystallites interact with numerous cellular systemsin vivo, and some of these interactions may lead to altered cellular function. One measure of crystal-membrane interactions is crystal-induced membranolysis of human red blood cells. Hemolytic potentials at constant crystal surface areas were measured at 1, 2, and 4 hours for 29 different preparations of apatite. Each apatite sample was characterized by its morphology, particle size, % CO3, zeta potential, and broadening of the (211), (112), (300), (202), and (002) diffraction maxima. Only the surface area/g and the X-ray powder diffraction line broadening showed a significant inverse correlation with hemolytic potential. These parameters were related to each other, and are indications of the degree of crystallinity.

Tissue deposits of basic calcium phosphate (BCP) crystals are associated with various clinical manifestations of inflammation. We addressed the possibility that native proteins modify the ability of hydroxyapatite (HA) crystals to stimulate human inflammatory cells. Neutrophil superoxide release and chemiluminescence in response to HA crystals (0.3-4.0 mg/ml) were blunted by serum and plasma. Inhibitory activity was progressively removed from serum by sequential adsorption with HA crystals, suggesting that the inhibitors were crystal-bound proteins. Thus, we characterized HA crystal-bound plasma proteins by O'Farrell gels: Fibronectin, transferrin, albumin, alpha 2-HS glycoprotein (AHSG), alpha 1-proteinase inhibitor, alpha 1-acid glycoprotein, Gc globulin, haptoglobin, and high density lipoprotein apolipoproteins were major bound species. Of these, AHSG was the most active inhibitor of HA-induced neutrophil superoxide release, and this glycoprotein partially (60%) restored inhibitory activity to HA-adsorbed serum. AHSG also bound in vitro to the related BCP crystal, octacalcium phosphate, but only minimally to calcium pyrophosphate dihydrate crystals and monosodium urate crystals. Suppressive effects on neutrophil stimulation exhibited by AHSG were also specific for BCP crystals. AHSG was present in noninflammatory synovial fluids bound to synthetic HA crystals in vitro, and AHSG could be detected on native synovial fluid HA crystals. We conclude that the binding of AHSG may modulate the inflammatory potential of BCP crystals.

The role of the complement system in the pathogenesis of crystal-induced pulmonary inflammation and fibrosis was evaluated using a mouse model of silicosis and congenitally complement-deficient mice. Mice lacking the fifth component of complement (B10.D2/o) were compared to C5-sufficient animals (B10.D2/n) for pulmonary changes following intratracheal instillation of silica crystals. Complement-deficient mice demonstrated a significant reduction compared to complement-sufficient mice in both cell number and protein content of lung lavage fluid throughout the 12 weeks following silica exposure. Lung hydroxyproline content (indicative of collagen deposition) was equivalent for both strains and significantly higher than controls at all times points following silica instillation. Moreover, studies in vitro have shown that silica crystals are capable of activating complement via the alternative pathway. These studies indicate that the complement system may be responsible for some of the pulmonary inflammation, but not fibrosis elicited by silica exposure.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConvergent synthesis of polyether ionophore antibiotics: an approach to the synthesis of the monensin tetrahydropyran-bis(tetrahydrofuran) via the ester enolate Claisen rearrangement and reductive decarboxylationRobert E. Ireland, Daniel W. Norbeck, Gretchen S. Mandel, and Neil S. MandelCite this: J. Am. Chem. Soc. 1985, 107, 11, 3285–3294Publication Date (Print):May 1, 1985Publication History Published online1 May 2002Published inissue 1 May 1985https://doi.org/10.1021/ja00297a039RIGHTS & PERMISSIONSArticle Views1561Altmetric-Citations89LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Ca2P2O7·4H2O, monoclinicP21/c, a=6.008(1),b=25.034(4),c=6.837(1) Å,β=109.7 (1)°,Z=4,D0=2.20,D c =2.24 g cm−3. The structure was solved by direct methods and refined by block-diagonal matrix least squares to a finalR value of 0.038. Both calcium atoms are seven coordinate. The\(\overline {P - O_T } \) distance is 1.510(6) Å, whereas the\(\overline {P - O_B } \) distance is 1.619(1) Å and the P-OB-P angle is 125.9(1)°.

Deposition of crystalline triclinic (t) and monoclinic (m) calcium pyrophosphate dihydrate (CPPD) in fibrocartilage and articular cartilage is the hallmark of chondrocalcinosis. Using biologic grade gelatin to model this crystal growth process, t-CPPD, m-CPPD, amorphous calcium pyrophosphate, orthorhombic calcium pyrophosphate tetrahydrate (o-CPPT), and 3 mixed calcium/sodium pyrophosphate salts were grown at physiologic pH. Amorphous and o-CPPT appeared to be kinetic precursor crystals in the formation of t-CPPD and m-CPPD. Optimal concentration ranges for the different crystals were determined.

Deposition of crystalline triclinic (t) and monoclinic (m) calcium pyrophosphate dihydrate (CPPD) in fibrocartilage and articular cartilage is the hallmark of chondrocalcinosis. Using biologic grade gelatin to model this crystal growth process, t-CPPD, m-CPPD, amorphous calcium pyrophosphate, orthorhombic calcium pyrophosphate tetrahydrate (o-CPPT), and 3 mixed calcium/sodium pyrophosphate salts were grown at physiologic pH. Amorphous and o-CPPT appeared to be kinetic precursor crystals in the formation of t-CPPD and m-CPPD. Optimal concentration ranges for the different crystals were determined.

AbstractAcylieren der lithiierten Oxazoline (I) bzw. (IV) mit den Acylchloriden (II) ergibt die stereoisomeren β‐Dicarbonylverbindungen (III) bzw. (V) mit stabilen chiralen Zentren.

The title compound is C16H20O5, MW=292.3, orthorhombic,P212121,a=9.741(2),b=29.391(7),c=5.354(1) Å from diffractometer measurements,V=1532.8 Å3,Z=4,D c =1.267 g cm−3,D o =1.271 g cm−3 (ether/1,1,2,2-tetrabromoethane), λ(Mo Kα)=0.71069 Å,F(000)=624,μ=1.02 cm−1, crystal dimensions 0.23×0.23×0.40 mm,R=0.049 for 1164 observed reflections. The molecule contains a possibly significant asymmetric ether linkage between the oxacyclohexane ring and the highly anisotropic benzyl ring. The packing consists of zigzagged chains parallel to thea-axis formed by hydrogen bonds. The chains are separated by van der Waals contacts.