Simultaneous measurements of calcium oxalate crystal nucleation and aggregation: impact of various modifiers

1995 ◽  
Vol 23 (4) ◽  
pp. 231-238 ◽  
Author(s):  
B. Hess ◽  
U. Meinhardt ◽  
L. Zipperle ◽  
R. Giovanoli ◽  
P. Jaeger
Keyword(s):  
Calcium Oxalate ◽  
Crystal Nucleation ◽  
Calcium Oxalate Crystal ◽  
Simultaneous Measurements

scholarly journals Urinary calcium oxalate crystal growth inhibitors.

1994 ◽  
Vol 5 (5) ◽  
pp. S46
Author(s):  
E M Worcester
Keyword(s):  
Crystal Growth ◽  
Calcium Oxalate ◽  
Stone Formation ◽  
Bone Matrix ◽  
Urinary Calcium ◽  
Crystal Nucleation ◽  
Calcium Oxalate Crystal ◽  
Stone Formers ◽  
High Concentrations ◽  
Renal Tubular

Calcium stones occur because renal tubular fluid and urine are supersaturated with respect to calcium oxalate and phosphate. The process of stone formation includes crystal nucleation, growth, aggregation, and attachment to renal epithelia. Urine contains macromolecules that modify these processes and may protect against stone formation. Attention has focused especially on inhibitors of crystal growth, and several have been isolated from urine, including nephrocalcin, an acidic phosphorylated glycoprotein that contains several residues of gamma-carboxyglutamic acid per molecule; osteopontin (uropontin), a phosphorylated glycoprotein also found in bone matrix; uronic acid-rich protein, which contains a covalently bound glycosaminoglycan residue; and several others. Abnormalities in structure and/or function have been detected in some of these proteins in stone formers' urine. However, the overall ability of urinary macromolecules to inhibit calcium oxalate crystal growth is often normal in stone formers. Recently, attention has been focused on the ability of these molecules to inhibit other stages in stone formation. Nephrocalcin can inhibit crystal nucleation, for example, and both nephrocalcin and Tamm-Horsfall protein inhibit crystal aggregation. Nephrocalcin and Tamm-Horsfall protein from stone formers are less active in preventing aggregation, and under some conditions, Tamm-Horsfall protein may promote the formation of crystal aggregates, especially in the presence of high concentrations of calcium. The structural abnormalities responsible for impaired inhibitory activity are not completely understood.

An SEM study of raphide crystal initials in the leaves of vitis (grape)

1995 ◽  
Vol 53 ◽  
pp. 984-985
Author(s):  
H. J. Arnott ◽  
M. A. Webb ◽  
L. E. Lopez
Keyword(s):  
Calcium Oxalate ◽  
Water Soluble ◽  
Calcium Oxalate Crystals ◽  
Calcium Oxalate Crystal ◽  
Oxalate Crystals ◽  
Large Numbers ◽  
Sem Study ◽  
The Matrix ◽  
Crystal Cells ◽  
Crystal Idioblast

Many papers have been published on the structure of calcium oxalate crystals in plants, however, few deal with the early development of crystals. Large numbers of idioblastic calcium oxalate crystal cells are found in the leaves of Vitis mustangensis, V. labrusca and V. vulpina. A crystal idioblast, or raphide cell, will produce 150-300 needle-like calcium oxalate crystals within a central vacuole. Each raphide crystal is autonomous, having been produced in a separate membrane-defined crystal chamber; the idioblast''s crystal complement is collectively embedded in a water soluble glycoprotein matrix which fills the vacuole. The crystals are twins, each having a pointed and a bidentate end (Fig 1); when mature they are about 0.5-1.2 μn in diameter and 30-70 μm in length. Crystal bundles, i.e., crystals and their matrix, can be isolated from leaves using 100% ETOH. If the bundles are treated with H2O the matrix surrounding the crystals rapidly disperses.

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