Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CRYSTALLIZATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1995

A new subgroup of lectin-bound biliary proteins binds to cholesterol crystals, modifies crystal morphology, and inhibits cholesterol crystallization.

Biliary proteins inhibiting or promoting cholesterol crystallization are assumed to play a major role in cholesterol gallstone pathogenesis. We now report a new group of biliary proteins that bind to cholesterol crystals, modify crystal morphology, and inhibit cholesterol crystallization. Various glycoprotein mixtures were extracted from abnormal human gallbladder bile using lectin affinity chromatography on concanavalin A, lentil, and Helix pomatia columns and were added to supersaturated model bile. Independent of the protein mixtures added, from the cholesterol crystals harvested, the same four GPs were isolated having molecular masses of 16, 28, 63, and 74 kD, respectively. Each protein was purified using preparative SDS-PAGE, and influence on cholesterol crystallization in model bile was tested at 10 microg/ml. Crystal growth was reduced by 76% (GP63), 65% (GP16), 55% (GP74), and 40% (GP28), respectively. Thus, these glycoproteins are the most potent biliary inhibitors of cholesterol crystallization known so far. Evidence that the inhibiting effect on cholesterol crystallization is mediated via protein-crystal interaction was further provided from scanning electron microscopy studies. Crystals grown in presence of inhibiting proteins showed significantly more ordered structures. Incidence of triclinic crystals and regular aggregates was shifted from 30 to 70% compared with controls. These observations may have important implications for understanding the role of biliary proteins in cholesterol crystallization and gallstone pathogenesis.

Analysis of Variance↗
PubMed2001

Laboratory multiple-crystal X-ray topography and reciprocal-space mapping of protein crystals: influence of impurities on crystal perfection.

Double-axis multiple-crystal X-ray topography, rocking-curve measurements and triple-axis reciprocal-space mapping have been combined to characterize protein crystals using a laboratory source. Crystals of lysozyme and lysozyme crystals doped with acetylated lysozyme impurities were examined. It was shown that the incorporation of acetylated lysozyme into crystals of lysozyme induces mosaic domains that are responsible for the broadening and/or splitting of rocking curves and diffraction-space maps along the direction normal to the reciprocal-lattice vector, while the overall elastic lattice strain of the impurity-doped crystals does not appear to be appreciable in high angular resolution reciprocal-space maps. Multiple-crystal monochromatic X-ray topography, which is highly sensitive to lattice distortions, was used to reveal the spatial distribution of mosaic domains in crystals which correlates with the diffraction features in reciprocal space. Discussions of the influence of acetylated lysozyme on crystal perfection are given in terms of our observations.

Acetylation↗
PubMed2001

Irreversible single-crystal to polycrystal and reversible single-crystal to single-crystal phase transformations in cyanurates.

4,6-Dimethoxy-3-methyldihydrotriazine-2-one (1) undergoes a single-crystal to single-crystal reversible phase transformation at 319 K. The low-temperature phase crystallizes in monoclinic space group P2(1)/n with two crystallographically independent molecules in the asymmetric unit. The high-temperature phase is obtained by heating a single crystal of the low-temperature phase. This phase is orthorhombic, space group Pnma, with the molecules occupying a crystallographic mirror plane. The enthalpy of the transformation is 1.34 kJ mol(-1). The small energy difference between the two phases and the minimal atomic movement facilitate the single-crystal to single-crystal reversible phase transformation with no destruction of the crystal lattice. On further heating, the high-temperature phase undergoes methyl rearrangement in the solid state. 2,4,6-Trimethoxy-1,3,5-triazine (3), on the other hand, undergoes an irreversible phase transformation from single-crystal to polycrystalline material at 340 K with an enthalpy of 3.9 kJ mol(-1); upon further heating it melts and methyl rearrangement takes place.

Journal Article↗
PubMed1998

Protein crystal growth in the Advanced Protein Crystallization Facility on the LMS mission: a comparison of Sulfolobus solfataricus alcohol dehydrogenase crystals grown on the ground and in microgravity.

Crystals of alcohol dehydrogenase from Sulfolobus solfataricus were grown in the Advanced Protein Crystallization Facility during the Life and Microgravity Sciences Spacelab mission on the US Space Shuttle. Large diffracting crystals were obtained by dialysis, whereas only poor-quality crystals were obtained by vapour diffusion. The quality of both the microgravity and ground-based crystals was analysed by X-ray diffraction. There was some improvement in terms of size and diffraction resolution limit for the microgravity crystals. However, the twinning observed in the Earth-grown crystals was also present for those grown in microgravity.

Alcohol Dehydrogenase↗
PubMed1997

[Polarizing microscopy of crystalline drugs based on the crystal habit determination for the purpose of a rapid estimation of crystal habits, particle sizes and specific surface areas of small crystals].

In 1939 the author reported the results of measured refractive indices of about a hundred crystalline drugs listed in [JP V] at the Takeda Research Laboratory using a Leitz PM polarizing microscope and newly developed immersion oils. When the author had reopened the study of crystalline drugs using a polarizing microscope at the Kobe-Gakuin University starting from 1975 one of the main purposes was to clarify the relation between crystal habits and refractive indices. It had been found that in most cases of crystal habits refractive indices were uniquely measured from a predominant pair of faces forming superior the habit, and they were called as "key refractive indices". The author and his co-workers tried to investigate the possibility of measuring the key refractive indices widely from all the obtainable crystalline drugs listed in the [JP X] or [JP XI], co-operating with the Pharmacy of Kobe University Hospital. Thus, more than 170 kinds of crystalline drugs were tested for their key refractive indices and found that they were measured from about 60-70% of tested drugs. It was also clarified that the difference of 2 key refractive indices, (n2 - n1), the birefringence of the section, was also an unique invariable number for the habit, and it played an important role not only for the graphic representation of log(n2 - n1), abscissa, against (n1, n2), ordinate, for the sake of an analytical purpose but also to measure a thickness of a section (habit) using a retardation color. Then, it had been cleared that the similarity of crystal habits in the microscopic field was based on the facts of measuring the same key refractive indices, and the author had developed a chart for measuring key refractive indices as well as producing a 3 dimensional orthographic projection of a crystal habit simultaneously applying a thickness measuring method using a birefringence. Finally 3 dimensional parameter a, b, c of a crystal habit and "habit coefficients" T: square root of ab/c and L: b/c were determined from the orthographic projection. In conclusion using the similarity in crystal habits the distributions of particle sizes and specific surface areas of all the crystals in the microscopic field had been calculated by a personal computer putting in necessary habit coefficients and obtained data of parameter b. The relation between 2 dispersions of particle sizes in log (V) and specific surface areas in log (SSA) were shown under the rectangular coordinates log (V) on the abscissa and log (SSA) on the ordinate, where the loci of log (SSA) formed simple striped pattern composed of parallel straight lines depending on habit coefficients. It would be possible to estimate the value of a specific surface area of any crystalline substance by plotting the value of log (V) on the straight line of a locus of log (SSA) having the same habit coefficients.

Biological Availability↗
PubMed2001

Diels-Alder topochemistry via charge-transfer crystals: novel (thermal) single-crystal-to-single-crystal transformations.

The solid-state [4+2] cycloaddition of anthracene to bis(N-ethylimino)-1,4-dithiin occurs via a unique single-phase topochemical reaction in the intermolecular (1:1) charge-transfer crystal. The thermal heteromolecular solid-state condensation involves the entire crystal, and this rare crystalline event follows topochemical control during the entire cycloaddition. As a result, a new crystalline modification of the Diels-Alder product is formed with a crystal-packing similar to that of the starting charge-transfer crystal but very different from that of the (thermodynamically favored) product modification obtained from solution-phase crystallization. Such a single-phase transformation is readily monitored by X-ray crystallography at various conversion stages, and the temporal changes in crystallographic parameters are correlated with temperature-dependent (solid-state) kinetic data that are obtained by 1H NMR spectroscopy at various reaction times. Thus, an acceleration of the solid-state reaction over time is found which results from a progressive lowering of the activation barrier for cycloaddition in a single crystal as it slowly and homogeneously converts from the reactant to the product lattice.

Journal Article↗
PubMed1989

Calcium pyrophosphate and monosodium urate crystal interactions with neutrophils: effect of crystal size and lipoprotein binding to crystals.

"Small" (between 75-98% of crystals less than or equal to 10 microns) and "large" (between 81-93% of crystals greater than 10 microns) size fractions of monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate triclinic (CPPD) crystals were incubated with human neutrophils and crystal induced neutrophil cytolysis monitored by measuring the release of lactate dehydrogenase. "Small" size fractions of MSUM and CPPD gave higher percent lysis values than "large" crystals. The binding of high density lipoproteins (HDL) and low density lipoproteins (LDL) to the crystals was quantitated. HDL and LDL bound in significant amounts to both CPPD and MSUM and strongly inhibited CPPD and MSUM induced neutrophil cytolysis. We propose that HDL and LDL bound to MSUM and CPPD may play important roles in the regulation of gouty inflammation.

Apolipoproteins↗
PubMed1993

Evidence for crystal environment dominating base sequence effects on DNA conformation: crystal structures of the orthorhombic and hexagonal polymorphs of the A-DNA decamer d(GCGGGCCCGC) and comparison with their isomorphous crystal structures.

We have determined the structure of the A-DNA decamer d(GCGGGCCCGC) in two crystal forms, orthorhombic and hexagonal, at 1.7- and 1.8-A resolution, respectively. In the orthorhombic form, the fifth guanine residue has nearly trans-trans conformations for the alpha-gamma backbone torsions, as in the isomorphous orthorhombic structure d(CCCGGCCGGG) [Ramakrishnan, B., & Sundaralingam, M. (1993) J. Mol. Biol. 231, 431-444]. However, in the hexagonal form, the eighth cytosine residue adopts the trans-trans conformations for the backbone alpha-gamma torsions, as in the isomorphous hexagonal structure d(ACCGGCCGGT) [Frederick, C. A., Quigley, G. J., Teng, M.-K., Coll, M., van der Marel, G. A., van Boom, J. H., Rich, A., & Wang, A. H.-J. (1989) Eur. J. Biochem. 181, 295-307]. Even though the average helix and base-pair parameters are nearly the same in the two polymorphous crystal forms having the same sequence, many of the base-dependent local helix parameters are quite different. However, in the isomorphous crystal forms, in spite of the differing base sequences, the local helix and base-pair parameters of the duplexes are nearly the same. This indicates that, in crystals, the local conformation of a DNA structure is affected severely by the crystal packing environment rather than by the base sequence.

Base Sequence↗
PubMed2002

Crystallization and preliminary X-ray diffraction analysis of the trigonal crystal form of Saccharomyces cerevisiae alcohol dehydrogenase I: evidence for the existence of Zn ions in the crystal.

Saccharomyces cerevisiae alcohol dehydrogenase I crystallized as trigonal plates using 20% 2-propanol and 20% PEG 4000 in 0.1 M sodium citrate buffer pH 5.6 in the presence of 1 mM NAD(+). The crystals diffract to 3.0 A resolution and belong to the trigonal space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 146.3, c = 68.1 A, alpha = beta = 90, gamma = 120 degrees. X-ray data were collected from frozen crystals at the 17-ID beamline of the Advanced Photon Source. A Zn fluorescence scan of the crystal produced a peak at 9671.6 eV, suggesting the existence of Zn ions in the crystal.

Alcohol Dehydrogenase↗
PubMed1987

Crystal structure of two crystal forms of 9 alpha-fluorocortisol acetate: variation of the conformation of the A ring of steroids due to crystal packing.

This paper reports the crystal structure of the propanol solvate of 9 alpha-fluorocortisol acetate, which crystallizes in the monoclinic space group P21 [a = 7.470 (6), b = 14.78 (1), c = 12.310 (9), beta = 105.2 degrees, Z = 2, R = 0.061, and the tetragonal unsolvated crystal form (a = b = 9.208 (2), c = 49.284 (9), P4(1)2(1)2, Z = 8, R = 0.050)]. The molecular structure of fluorocortisol acetate in the two crystal forms differs primarily in the A ring and acetoxy orientation. The A ring of the steroid in the tetragonal crystal was found to be disordered, and exists in both a normal and inverted conformation. The A ring of the steroid in the monoclinic propanol solvate has the normal (1 alpha, 2 beta half-chain) conformation. The differences in the conformation of the side chain and the A ring appear to reflect the conformational variability in 9 alpha-fluorocortisol acetate.

Fludrocortisone↗
PubMed1988

Structural rearrangements during crystal-liquid-crystal and gel-liquid-crystal phase transitions in aqueous dispersions of dipalmitoylphosphatidylethanolamine. A time-resolved X-ray diffraction study.

The mechanism and kinetics of the crystal-liquid-crystal (Lc----L alpha) and gel-liquid-crystal (L beta----L alpha) transitions of the L-enantiomer and racemic dipalmitoylphosphatidylethanolamine have been examined in temperature scans and jumps using time-resolved X-ray diffraction methods. The Lc----L alpha transformations (at 66 degrees C for L-dipalmitoylphosphatidylethanolamine and 82 degrees C for DL-dipalmitoylphosphatidylethanolamine) were found to be two-state (first-order) processes characterised by co-existence of the initial Lc and final L alpha states during the transition with the absence of any detectable intermediates states. The transition mechanism involves firstly, disordering of the hydrocarbon chains which makes a major contribution to the transition enthalpy and secondly by a transition in the lamellar repeat spacing. The overall relaxation time of the Lc----L alpha transition of L-dipalmitoylphosphatidylethanolamine during temperature jumps of 4.5 degrees C/s was about 10 s. A gradual increase in the gel-state interchain spacing during the L beta----L alpha transitions of L- and DL-dipalmitoylphosphatidylethanolamine preceded a broadening of the wide-angle diffraction peak. There was a concomitant and continuous increase of the lamellar repeat spacing to values typical of the L alpha phase with increasing temperature. This sequence of events is completely reversible on cooling with a temperature hysteresis of 5-6 degrees C. The relaxation times of the L beta---L alpha transitions during jumps of 4.5 degrees C/s were about 2 s in both the heating and cooling directions.

Crystallization↗
PubMed2001

Electro-optic behavior of liquid-crystal-filled silica opal photonic crystals: effect of liquid-crystal alignment.

Photonic crystals made of nematic liquid crystal intercalated into the void space of close-packed silica spheres (synthetic porous opal) exhibit significant electric-field-induced shift of the optical Bragg reflection peak when the liquid crystal has the long molecular axis oriented parallel to the sphere surfaces. No such effect is observed for comparable fields when the long-axis orientation is normal to the sphere surfaces.

Journal Article↗
PubMed1995

The application of crystal soaking technique to study the effect of zinc and cresol on insulinotropin crystals grown from a saline solution.

PURPOSE: The purpose of this study is to investigate the effect of zinc and cresol on the structure of insulinotropin crystals. METHODS: Insulinotropin crystals grown from a saline solution were treated with zinc and/or m-cresol using a crystal soaking technique. The effects of these additives on the crystal structure were investigated with powder X-ray diffraction, photomicrography, and differential scanning calorimetry. The molecular interaction between insulinotropin and m-trifluorocresol in solution was also studied by 19F NMR: RESULTS: The data suggest that the original crystals grown from a saline solution have relatively weak lattice forces. After the addition of m-cresol to the suspension of the insulinotropin crystals, the crystals were immediately rendered amorphous. The m-cresol molecules which diffused into the crystals through solvent channels may have disturbed the lattice interactions that maintain the integrity of the crystal. In contrast, the zinc added to the suspension stabilized the crystal lattice so that the subsequent addition of m-cresol did not alter the integrity of the crystals. A marked increase in melting point (206 degrees versus 184 degrees) and heat of fusion (24.6 J/g versus 1.4 J/g) of the crystals was observed after the treatment with zinc. The solubility of the zinc treated crystals in a pH 7.1 phosphate buffered saline was 1/20 of that of the original crystals. CONCLUSION: When the insulinotropin crystals were treated with the additives using a crystal soaking method, the crystals underwent structural changes. Zinc stabilized the crystal lattice, and reduced the solubility of the peptide.

Amino Acid Sequence↗
PubMed1995

Improved static compression behaviors and tablettabilities of spherically agglomerated crystals produced by the spherical crystallization technique with a two-solvent system.

PURPOSE: Poorly compressible crystals of acebutolol hydrochloride were agglomerated by the spherical crystallization technique with a two-solvent system to improve the compressibility for direct tabletting. The mechanism of improvements in static compression behaviors and tablettabilities of the spherically agglomerated crystals were investigated. METHODS: The improvement of static compression behaviors of the agglomerated crystals was determined by measuring the stress relaxations and elastic recoveries of compressed powder of original and agglomerated crystals. The improved tablettability of agglomerated crystals was evaluated by the pressure transmission ratio upon compression, the ejection pressure for releasing the tablet from the die and the tablet strength, i.e., tensile strength required for breaking. RESULTS: The higher relaxation pressure and the lower elastic recovery of the agglomerated crystals than of the original crystals were found. The pressure transmission ratio data showed that the friction pressures of the two crystals were similar during the compression period. The ejection pressure of the agglomerated crystals was lower than that of the original crystals. The tensile strength of the tablet of agglomerated crystals was greater than that of the original crystals. CONCLUSIONS: The compressibility and tablettability of the spherically agglomerated crystals prepared by the spherical crystallization technique were much improved due to their increased plastic property and reduced adhesive property compared to the original crystals.

Acebutolol↗
PubMed1994

Phospholipid molecular species influence crystal habits and transition sequences of metastable intermediates during cholesterol crystallization from bile salt-rich model bile.

Despite its importance in cholesterol gallstone formation, crystallization of cholesterol from bile is poorly understood, especially with respect to the influences of other biliary lipids. We reported recently (Konikoff et al. J. Clin. Invest. 1992. 90: 1155-1160) that cholesterol can crystallize from model and native biles as filamentous crystals covered by a surface layer of lecithin molecules. During growth, filamentous crystals transformed via metastable intermediates into classical plate-like cholesterol monohydrate crystals. Using the same dilute (1.2 g/dl total lipid) bile salt-rich (97.5 moles %) model bile supersaturated with cholesterol, we have studied the effects of natural egg yolk, soy bean as well as single molecular species of lecithins, other phospholipids and related lipid classes on early filamentous cholesterol crystallization, as well as transformations between crystal habits and their growth to equilibrium cholesterol monohydrate plates. After extraction and derivatization, HPLC analysis revealed that the surfaces of filamentous crystals were enriched preferentially with lecithin molecular species having longer and more saturated sn-1 and sn-2 acyl chains compared to mixed lecithin species of whole bile. In contrast, the molecular species distribution of lecithins on equilibrium plate-like crystals resembled that of whole bile. After incubation of pre-formed anhydrous cholesterol and cholesterol monohydrate crystals in cholesterol-free lipid solutions, we demonstrated that surface-adsorbed lecithins were not preferentially enriched excluding nonspecific lecithin adsorption. Time-sequences and transformations between metastable crystalline intermediates were altered markedly by specific phospholipid species: model biles composed of saturated short-chain, medium-chain, and polyunsaturated long-chain lecithins induced rapid precipitation of short filamentous crystals that became plate-like slowly by an "arborization pattern." Long-chain saturated lecithins and natural sphingomyelins retarded cholesterol crystallization markedly, and filamentous as well as metastable intermediate crystals made transient appearances only after plate-like crystals had formed. These observations suggest that phospholipid molecular species and class influence the earliest events in cholesterol crystallization from bile salt-rich model bile. Furthermore, as the molecular species of lecithins adsorbed onto filamentous cholesterol crystals were more saturated than in whole bile and essentially identical to those in biliary vesicles, this finding provides chemical evidence for a vesicular origin of the critical cholesterol nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)

Adsorption↗
PubMed1993

Crystallization of Old Yellow Enzyme illustrates an effective strategy for increasing protein crystal size.

Old Yellow Enzyme (OYE) was the first flavoenzyme discovered, and has been widely used as a model flavoenzyme. Three crystal forms have been grown from natural protease-nicked OYE and one has been grown from intact recombinant OYE. The recombinant OYE crystals are best suited for structure determination and grow from a solution containing polyethylene glycol and MgCl2. They belong to space group P4(3)2(1)2 with unit cell dimensions a = b = 142.88 A, c = 43.01 A and have a single OYE chain per asymmetric unit. In order to optimize the production of large single crystals, we have carried out a systematic study of crystal size versus drop volume. Crystallographic lore holds that the volume of the medium in which the crystals are grown should have a significant effect on the final size of the crystals produced. However, a systematic investigation of the degree to which the volume of the crystallization sample affects the final size of the crystals has not been reported. In order to investigate this phenomenon, drops were set up in both hanging and sandwich geometry at a variety of drop volumes, but otherwise identical crystallization conditions. A 60-fold increase in drop volume produced a 730-fold increase in crystal volume, and a simultaneous increase in the effective diffraction limit of the crystals from near 2.5 A to well beyond 2.0 A resolution. The dramatic crystal volume increase appears to be due both to the increased amount of protein and the slower equilibration rates associated with larger drops. Our results also emphasize that the quality of diffraction data may often be limited by crystal size rather than intrinsic crystal order even in the case of reasonably sized (200 to 400 microns) crystals.

Crystallization↗
PubMed2000

Citrate determines calcium oxalate crystallization kinetics and crystal morphology-studies in the presence of Tamm-Horsfall protein of a healthy subject and a severely recurrent calcium stone former.

BACKGROUND: The aim of this study was to measure the effects of normal (nTHP) and abnormal stone former Tamm-Horsfall protein (SF-THP) on calcium oxalate (CaOx) nucleation and aggregation as well as on crystal morphology, in presence or absence of citrate. METHODS: Nucleation and aggregation of CaOx crystals from a supersaturated, stirred solution (200 mM NaCl, 10 mM Na-acetate, pH 5.70, 5 mM Ca and 0.5 mM Ox) were studied by spectrophotometric time-course measurements of OD at 620 nm (OD(620)). Measured parameters were induction time t(I) (time to induce formation of detectable particles), S(N), (slope of increase of OD(620), mainly due to crystal nucleation), and S(A), (slope of decrease of OD(620) after equilibrium has been reached, due to crystal aggregation). Effects of citrate, nTHP and SF-THP on these parameters were measured, and scanning electron microscopy (SEM) was performed. RESULTS: At 1.5, 2.5 and 3.5 mM, citrate increased t(I) and inhibited crystal nucleation (by 78-87%) as well as aggregation (by 63-70%), and smaller CaOx crystals (length/width ratio 1.7+/-0.1) than under standard conditions (length/width 3.9+/-0.5) were visible (P<0.001). Normal THP at 30 and 40 mg/l inhibited crystal nucleation and, more strongly, aggregation (inhibition 76-81%). SEM revealed a decrease in length/width ratio to 2.6+/-0.4 (P=0.051 vs standard conditions) and less aggregation than without nTHP. At all concentrations tested, SF-THP reduced t(I) (P=0.0001 vs standard conditions) and promoted aggregation (inhibition -48 to -33%); crystals were elongated with a length/width ratio of 4.3+/-0.6 (P<0. 05 vs nTHP). When simultaneously present with nTHP, citrate enhanced the inhibitory effects of nTHP, producing the smallest (length/width 1.5+/-0.1) and least aggregated crystals. Finally, 3.5 mM citrate turned promotory SF-THP into a crystallization inhibitor with abundant small and clustered, but not aggregated crystals. CONCLUSION: Citrate appears to be the main determinant of CaOx crystallization rates and crystal morphology in the presence of nTHP as well as SF-THP. Its effects appear to predominate over those of THP, since even promotory SF-THP is turned into a crystallization inhibitor in the presence of citrate. This re-emphasizes at a morphological level what has been concluded from functional as well from clinical studies, namely that citrate is needed in urine at equimolar concentrations to calcium in order to prevent the formation of large crystal aggregates in presence of abnormal THP.

Adult↗
PubMed2002

Urinary crystallization inhibitors do not prevent crystal binding.

PURPOSE: Renal stone formation requires the persistent retention of crystals in the kidney. Calcium oxalate monohydrate (COM) crystal binding to Madin Darby canine kidney strain I (MDCK-I), a cell line that resembles the epithelium in the renal distal tubule/collecting duct, is developmentally regulated, while LLC-PK1 cells (American Type Tissue Collection), which are widely used as a model of the renal proximal tubule, bind crystals irrespective of their stage of epithelial development. Whereas to our knowledge the binding molecules for COM at the surface of LLC-PK1 cells are still unknown, crystals adhere to the hyaluronan (HA) rich pericellular matrix transiently expressed by mobile MDCK-I cells. In the current study we investigated whether crystal binding to either cell type is influenced by urinary substances, including glycoprotein inhibitors of crystallization MATERIALS AND METHODS: We studied crystal binding to MDCK-I cells during wound repair, to confluent LLC-PK1 cells and to HA immobilized on a solid surface using [14C] COM pretreated or not pretreated with urine from healthy male volunteers. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis were performed to assess whether the crystals became coated with urine derived proteins RESULTS: Western blot analysis demonstrated that pretreated COM crystals were covered with protein inhibitors of crystallization. However, this protein coat had no significant effect on the level of crystal binding to either cell type. In contrast, the adherence of urine treated crystals to immobilized HA was significantly reduced CONCLUSIONS: The adherence of crystals to pericellular matrixes may encompass more than their simple fixation to the polysaccharide HA. Calcium oxalate crystal retention is not prevented by coating crystals with urinary constituents such as glycoproteins and, therefore, may predominantly depend on the surface properties of the renal tubular epithelium.

Animals↗