An improved colorimetric procedure for urine oxalate.

Fungal mats of Hysterangium crassum (Tul. and Tul.) Fischer occupied a mean of 9.6% of the upper 10 cm of soil developed under a 40–65 yr old stand of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in Oregon. This hypogeous basidiomycete exudes large amounts of oxalic acid, some of which precipitates with Ca in microscopic crystals of calcium oxalate, resulting in a mean CaC2O4 content of 82g m−2 for the entire soil. Soil oxalate concentration was significantly greater within fungal mats (P

Calcium oxalate accumulation and soil weathering in mats of the hypogeous fungus Hysterangium crassum

Abstract In seven patients with resection of the distal ileum, calcium oxalate nephrolithiasis and increased urinary excretion of oxalate (64 to 135 mg per 24 hours) developed. Cholestyramine therapy (4 g four times a day) lowered the 24-hour urinary excretion of oxalate to normal in the four patients in whom it was used. Urinary excretion of oxalate was measured in an additional 42 patients with various types of intestinal disorders without evidence of nephrolithiasis. Five of 18 patients with ileal resection, two of seven with bacterial over-growth, and six of 15 with miscellaneous conditions, including nontropical sprue and cirrhosis, had hyperoxaluria.

Acquired hyperoxaluria, nephrolithiasis, and intestinal disease. Description of a syndrome.

OBJECTIVE

To evaluate the prophylactic potential of a herbal decoction from Herniaria hirsuta, a medicinal plant widely used in Morocco to treat kidney stones, by assessing the effect of oral administration in experimentally induced calcium oxalate (CaOx) nephrolithiasis in rats.



MATERIAL AND METHODS

Two groups of six rats each were rendered nephrolithic by treating with ethylene glycol 0.75% and ammonium chloride 1% for 3 days, and then ethylene glycol only for 3 weeks. Maintained on ethylene glycol, one group of rats was also given 1 mL/day of the plant decoction, while the others received 1 mL of water instead for 2 weeks. Urine samples (24 h) were collected individually at 1, 3, 7, and 14 days for physicochemical analysis. On completing the treatment the kidneys were collected and analysed by light microscopy.



RESULTS

The water intake and diuresis decreased in the treated rats; there was no significant difference in urinary pH between the groups. Urinary chemistry was apparently unaffected by the plant extract, except for the magnesium content, which was higher in treated rats. Crystalluria was characterized by the excretion of large CaOx monohydrate and dihydrate crystals in untreated, but smaller crystals in treated rats. The histology showed large deposits of CaOx crystals in all parts of the kidney in untreated rats but with almost no deposits in those of treated rats.



CONCLUSION

H. hirsuta has an impressive prophylactic effect on CaOx stones in nephrolithic rats; the effect did not seem to be mediated by biochemical or diuretic changes.

Prophylaxis of calcium oxalate stones by Herniaria hirsuta on experimentally induced nephrolithiasis in rats

Protective effect of the hydro-alcoholic extract of Rubia cordifolia roots against ethylene glycol induced urolithiasis in rats

The properties of oxalic acid are reviewed, together with the use that may be made of these in various methods of oxalate analysis, which are critically compared. Information is given on the oxalate content of biological fluids, urinary calculi, tissues, and foods.

A. Hodgkinson

Papers

Determination of Oxalic Acid in Biological Material