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An 80-year-old man presented to the emergency department after a fall at home. Serum studies demonstrated an anion and osmolal gap. Examination of the urine sediment showed calcium oxalate monohydrate crystals, suggestive of ethylene glycol toxicity.

Crystallization process has a major role in urolithiasis. In the present study, effect of two indigenous plants extracts namely Boerhavia diffusa and Bryophyllum pinnatum extract was determined on the crystallization of calcium oxalate crystals. Effect on the number, size and type of calcium oxalate crystals was observed. Results showed significant activity of both extracts against calcium oxalate crystallization at different concentrations (P < 0.05). Size of the crystals gradually reduced with the increasing concentration of both extracts. The number of calcium oxalate monohydrate crystals which are injurious to epithelial cells gradually reduced and at the highest concentration of extracts (100 mg/ml) completely disappeared (P < 0.05). These results confirm that B. diffusa and B. pinnatum extracts have antiurolithic activity and have the ability to reduce crystal size as well as to promote the formation of calcium oxalate dihydrate (COD) crystals rather than monohydrate (COM) crystals. Control of crystal size and formation of COD rather than COM crystals, in combination with the diuretic action of extracts is an important way to control urolithiasis.

When seen, some habits of calcium oxalate monohydrate crystals (whewellite) are so typical of ethylene glycol intoxication that they may be helpful for its diagnosis when circumstances are not clearly established.

Chitosan is widely used in the biomedical field due its chemical and pharmacological properties. However, intake of chitosan results in renal tissue accumulation of chitosan and promotes an increase in calcium excretion. On the other hand, the effect of chitosan on the formation of calcium oxalate crystals (CaOx) has not been described. In this work, we evaluated the antioxidant capacity of chitosan and its interference in the formation of CaOx crystals in vitro. Here, the chitosan obtained commercially had its identity confirmed by nuclear magnetic resonance and infrared spectroscopy. In several tests, this chitosan showed low or no antioxidant activity. However, it also showed excellent copper-chelating activity. In vitro, chitosan acted as an inducer mainly of monohydrate CaOx crystal formation, which is more prevalent in patients with urolithiasis. We also observed that chitosan modifies the morphology and size of these crystals, as well as changes the surface charge of the crystals, making them even more positive, which can facilitate the interaction of these crystals with renal cells. Chitosan greatly influences the formation of crystals in vitro, and in vivo analyses should be conducted to assess the risk of using chitosan.

Calcium oxalate (CaOx) is the main compound of human kidney stones, specifically calcium oxalate monohydrate crystals (COM). Normal human urine contains small crystals of calcium oxalate dihydrate (COD), which have reduced capacity to form stable aggregates and strong adhesion contacts to renal epithelial cell thus protecting kidney stone formation. Here, we report the preparation of a new monomethylitaconate grafted polymethylsiloxaner, which was able to promote and stabilize COD crystals. Although the mechanisms involved in control of CaOx polymorphism still remain unclear, we believe that research using synthetic polymers would provide interesting chemical clues to develop calculi preventing-compounds.

Human urine, and nephrocalcin (NC), a glycoprotein of probable kidney cell origin, greatly reduce consumption of calcium and oxalate from metastably supersaturated solutions seeded with calcium oxalate crystals, a phenomenon usually referred to as inhibition of crystal growth. We seeded metastably supersaturated calcium oxalate solutions with calcium oxalate monohydrate crystals under conditions of ion clamping to maintain constant composition and measured ion consumption from pump delivery rates. Consumption rates increased continuously with time as if the solutions were autocatalytic. After incubation, the seeds were covered with innumerable crystallites, which were also free and numerous in the solution, reflecting self-nucleation. The addition of 20% whole, dialyzed urine, or purified NC reduced ion consumption rates markedly, and the only crystals observed at the end of incubation were the large original seeds. Crystals precoated with concentrated dialyzed urine or NC also showed reduced ion consumption. Urine and NC from patients with nephrolithiasis inhibited nucleation less than normal controls. Self-nucleation seems to be the preferred response in sparsely seeded, ion-clamped, supersaturated solutions, such as exist in the nephron. Urine and NC suppress self-nucleation in vitro by adsorbing to the surface of calcium oxalate crystals.

This 73-year-old man presented with a self-inflicted stab wound, plasma ethanol level of 27 mg per deciliter, and a pH of 6.91. Analysis of the urine showed calcium oxalate monohydrate crystals. Free crystals were extensive.

Crystal-induced membranolysis of human red blood cells has been quantltated for calcium oxalate monohydrate and calcium oxalate dihydrate crystals. Calcium oxalate monohydrate crystals are significantly more membranolytic than calcium oxalate dihydrate crystals at constant surface area. If the crystal morphology of calcium oxalate monohydrate is altered by grinding, the lytic potential at constant surface area is markedly reduced. However, altered calcium oxalate dihydrate crystals are as lytic as natural calcium oxalate dihydrate crystals at constant surface area. Differences in the calcium oxalate monohydrate and dihydrate crystal structures, specifically the structural characteristics of the disordered water channel in calcium oxalate dihydrate, can explain these different membranolytic characteristics.

Urine sediments of dogs with experimentally induced ethylene glycol poisoning were examined by light microscopy and X-ray diffraction. Massive calcium oxalate crystalluria was observed in all poisoned dogs. By light microscopy, the frequency with which six-sided hippurate-like prisms and envelope forms of calcium oxalate dihydrate occurred was approximately equal. The hippurate-like crystals were shown to be calcium oxalate monohydrate by X-ray diffractometry.

Seed experiments on the growth of calcium oxalate monohydrate in vitro have given the following results. Chondroitin sulphate does not influence the growth but only the agglomeration. The main influence of heparin at all concentrations is to inhibit the agglomeration, but at concentrations greater than about 10−8 mol/l the growth is also inhibited. In the range 0.05–30 μmol/l there is a linear dependence between the percentage inhibition of the growth and the concentration of heparin.

Methods are described for growing calcium oxalate in silica and gelatin gels under different conditions. The results obtained indicate that, in silica gel, calcium oxalate grows into single individual crystals, twins, and rosettes. Bipyramidal calcium oxalate dihydrate crystals similar to those present in the urine of stone formers were prepared in the silica gel system. The gelatin gel offered a suitably structured substrate on which calcium oxalate monohydrate crystals grow into aggregates. The orientation pattern of calcium oxalate crystals suggests that the growth process is controlled by the stereospecificity of the gelatin medium supporting growth.

An attempt has been made to elucidate the role of alkalinization and chelation in the dissolution of both calcium oxalate monohydrate crystals and stones. Dissolution by these agents has been, measured at various concentrations over the pH range from 4 to 8. The alkalinizing agents used were sodium orthophosphate and sodium bicarbonate. The chelating agents were sodium ethylenediaminetetraacetate (EDTA) and sodium citrate.