The use of Daphnia magna for detection of okadaic acid in mussel extracts.

Okadaic acid (OA), the main toxin responsible for diarrheic shellfish poisoning (DSP) has toxicity for Daphnia magna (EC50 = 15 +/- 1.8 micrograms/l). A Daphnia bioassay was developed and used to analyse okadaic acid in mussel extracts. A linear correlation was found between OA concentration determined by the Daphnia bioassay and by HPLC assay (r = 0.85; p < 0.001). The Daphnia bioassay can measure OA levels 10 times below the threshold of the mouse bioassay method. It is an inexpensive sensitive tool which can be used in replacement of mouse bioassay for the screening of OA and some co-extracting toxins in mussel extracts.

[Fibronectin in the ascitic fluid: its diagnostic significance]. / La fibronectine dans le liquide d'ascite: sa signification diagnostique.

We studied fibronectin concentration in the ascitic fluid of 102 patients, 71 with cirrhosis, 13 with hepatocellular carcinoma, 12 with malignant peritonitis, and six with miscellaneous disease. Fibronectin concentrations in the first three groups were 45 +/- 45 mg/l, 54 +/- 84 mg/l, and 144 +/- 123 mg/l, respectively. The difference between patients with cirrhosis and malignant peritonitis was significant (p less than 0.01). However, fibronectin concentration greater than 100 mg/l had a sensitivity of 58 per cent and a specificity of 86 per cent for the diagnosis of malignant peritonitis. Ascitic fluid protein content over 30 g/l had the same sensitivity and specificity was 90 per cent. Among cirrhotic patients, high fibronectin concentrations were demonstrated in those with long-standing ascites (m = 134 +/- 58 mg/l) whereas the lowest concentrations were found in patients with severe hepatocellular failure (m = 12 +/- 9 mg/l). Concentrations were significantly different, according to whether or not spontaneous bacterial peritonitis occurred later (20 +/- 13 mg/l versus 52 +/- 49 mg/l); 83 per cent of patients with spontaneous bacterial peritonitis during their clinical course had initial fibronectin concentrations above 30 mg/l in their ascites. We conclude that: 1) measurement of fibronectin concentration in ascitic fluid is of poor diagnostic value for discrimination between malignant and non malignant ascitic, 2) low concentrations of fibronectin are associated with the occurrence of spontaneous bacterial peritonitis in cirrhotic patients. Hypothetically, the quantitative defect of fibronectin could be responsible for bacterial opsonization impairment in these patients.