Biochemical and physiological responses after exposure to microcystins in the crab Chasmagnathus granulatus (Decapoda, Brachyura).

Microcystins are usually the predominant cyanotoxins present in both drinking and recreational waters after cyanobacterial blooms. Their classic toxic effect is hepatotoxicity through inhibition of serine/threonine phosphatases. However, recent studies also reported oxidative stress generation and disruption of ion regulation in aquatic organisms after microcystins exposure. In the present study, aqueous extracts of Microcystis aeruginosa were administered to the estuarine crab Chasmagnathus granulatus (Decapoda, Brachyura) by gavage in variable doses (from 34 to 860 microg kg(-1)) and exposure times (6, 12, and 72 h). A control group was exposed to saline solution. Analyzed variables included oxygen consumption, lipid peroxidation (LPO), enzyme activities (glutathione S-transferases or GST; alanine aminotransferase or ALT; aspartate aminotransferase or AST; and lactate dehydrogenase or LDH), glycogen, and microcystins content. Oxygen consumption increased in organisms exposed for 12h to 860 microg kg(-1) of microcystins and a similar result was observed after 72 h at doses equal to or higher than 34 microg kg(-1). LPO levels increased in doses equal to or higher than 34 microg kg(-1) after 72 h. GST and LDH activities increased after 12 h (at a dose of 860 microg kg(-1)), but ALT and AST activities remained unaltered in all experimental conditions. Glycogen content decreased after 72 h exposure at doses equal to or higher than 172 microg kg(-1). After 12h of exposure to 860 microg kg(-1) of microcystins, the concentration found in the hepatopancreas of C. granulatus was 13.17+/-0.56 microg kg(-1). In crabs exposed to doses higher than 172 microg kg(-1) during 72 h this value raised to 32.14+/-4.12 microg kg(-1). The obtained results indicated that microcystins exposure led the tissue to an oxidative stress condition (high LPO levels), at least in part favored by the augment of oxygen consumption, altering the glycogen metabolism. GST responses were only observed in the short-term experiment (12 h) and no effect on classical markers of vertebrate liver damage (ALT and AST) was observed. Although the hepatopancreas from C. granulatus accumulated a relatively low concentration of toxins, it was enough to induce physiological and biochemical disturbances.

Repeatability of the sonographic assessment of fetal sucking and swallowing movements.

OBJECTIVE: To test the repeatability of sonography in the assessment of fetal sucking and swallowing movements. METHODS: Eighty normal fetuses of pregnant women with no systemic abnormalities were examined sonographically at 30-38 weeks of gestation. Sucking and swallowing movements were observed for 15 min and the face was visualized in frontal and lateral views. The examinations were recorded for later analysis by two independent observers and the 95% limits of agreement (Bland and Altman) method was used for inter- and intraobserver comparison. RESULTS: The mean +/- SD number of swallowing movements, sucking bursts and total sucking movements recorded by Observer 1 were 8.3 +/- 4.7, 9.9 +/- 9.3 and 35.8 +/- 48.0 and the equivalent values for Observer 2 were 8.2 +/- 4.8, 9.8 +/- 9.3 and 36.4 +/- 49.0, respectively. The mean (95% limits of agreement) interobserver difference was 0.1 (-1.4; 1.6), 0.1 (-2.2; 2.3) and -0.6 (-9.0; 7.9), and the mean (95% limits of agreement) intraobserver difference was 0.4 (-3.1; 3.9), 0.1 (-2.0; 2.2) and 1.0 (-10.7; 12.7) for swallowing movements, sucking bursts and total sucking movements, respectively. CONCLUSIONS: The high degree of intra- and interobserver repeatability disclosed in the sonographic analysis of fetal sucking and swallowing movements supports the applicability of sonographic assessment in normal fetuses.