[Hydatid cyst fluid (Echinococcus granulosus) biochemistry. Influence of site on cyst permeability].

Eleven metabolites were determined in 19 hydatid cyst fluids of variable size and localization, and in patients plasma before surgery. Specific indirect immunofluorescent antibody titration was carried out. Sodium (132 +/- 5.2 mmol/l), chloride (92.9 +/- 6.5 mmol/l) and bicarbonate (22.1 +/- 1.5 mmol/l) were found at the same concentration than in plasma. Potassium (5.4 +/- 0.3 mmol/l) and calcium levels (4.7 +/- 0.9 mmol/l) were higher than in plasma, and phosphate (0.1 +/- 0.03 mmol/l) decreased tenfold. Glucose (3.4 +/- 0.8 mmol/l), creatinine (39.3 +/- 7.2 mumol/l) and urea nitrogen (4.6 +/- 0.8 mmol/l) showed great variations. Cholesterol levels 0.06 +/- 0.03 mmol/l) were a hundredfold lower than in plasma. Total protein levels (0.34 +/- 0.09 g/l) were found at very low concentrations. Extra-pulmonary cysts showed significantly higher antibody titers than pulmonary cysts. No correlation was observed between the size of the cysts and the level of the immune response. Significant difference about the relative cholesterol concentration (cystic concentration/plasmatic concentration) was observed between pulmonary and extra-pulmonary cysts (respectively 0.0048 +/- 0.0032 and 0.018 +/- 0.01--p less than 0.05). No correlation was observed between the size of the cyst, or the corresponding levels of the immune response, and the cholesterol levels. The hypothesis of a greater membrane permeability in extra-pulmonary cyst is discussed.