Measurement of Urine Crystallites and Its Influencing Factors by Nanoparticle Size Analyzer

Abstract

The difference of urine crystallites under 1000 nm in 10 patients with urolithiasis and 10 healthy subjects with no history of urolithiasis was comparatively studied with the nanoparticle size analyzer. By comparing the differences of intensity-autocorrelation curve, polydispersity index (PDI), Zeta potential, and relative error of average diameter of the two kinds of urine crystallites, it was concluded that the urine crystallites of healthy subjects were more stable than those of patients. The urine crystallites of healthy subjects had a narrower size distribution from 100 nm to 350 nm and a better dispersion (PDI < 0.3). However, the urine crystallites of patients with urolithiasis had a wider distribution from dozens of nanometers to 1000 nm and a worse dispersion (PDI > 0.5). The best processing method for urine crystallites detection was found: after antisepticising and protein-coagulating with formaldehyde, the urine was diluted with distilled water of the same volume, then filtrated through a micropore film of 3 microm, and the filtrate was centrifugalized at 4000 rpm for 15 minutes. This method can remove the cell fragments and macromolecular substances in the urine without affecting the detection of the urine crystallites under 1000 nm. The results were consistent with those obtained by transmission electron microscope (TEM).

Changes in urinary nanocrystallites in calcium oxalate stone formers before and after potassium citrate intake

“…A smaller particle corresponds to a faster Brownian movement, leading to a faster scattering intensity change and an inferior signal correlation as well as quick variations in the attenuation of curves. [22][23][24] A faster attenuation of the autocorrelation curve corresponds to a steeper curve and shorter decay time. By contrast, larger particles correspond to slower Brownian movement, leading to a slower scattering intensity change and corresponding in turn, to better signal correlations and slower attenuation of the autocorrelation curve.…”

“…[1][2][3] Therefore, the crystallites in urine are crucial factors affecting the formation of uroliths. [4][5][6] Previous studies 5,6 have found differences between the urinary crystallites (,1000 nm in size) of patients with urolithiasis and healthy subjects without any urolithiasis history. These studies concluded that the morphology, particle size, aggregation, and crystal phase of nanocrystallites in the urine of lithogenic patients remarkably differ from those of healthy persons.…”

Interaction between submicron COD crystals and renal epithelial cells

“…10 However, the current research on adhesion between renal tubular epithelial cells and crystals mainly focuses on micron grade COM and COD crystals. 6,11 Only a few studies about nanocrystals in urine are available, 12,13 and the interaction between renal tubular epithelial cells and CaOxa crystals with a size of less than 200 nm has yet to be reported. In fact, numerous submicron microcrystals exist in urine, and these microcrystals are the basis for the formation of micron grade crystals.…”

Dietary Oxalate Induces Urinary Nanocrystals in Humans

“…The nanocrystals observed (i.e., 100-300 nm) were consistent with another study that reported urinary crystallites from healthy subjects ranging from 100 to 350 nm in size. 55 A large proportion of crystals we observed were larger than urinary exosomes, which range from 20 to 100 nm. 56,57 To ensure optimal measurements, we used a consistent camera level, detection threshold, focus, and flow rate, as each of these parameters could affect particle assessment.…”