Seasat altimeter calibration: initial results.

Preliminary analysis of radar altimeter data indicates that the instrument has met its specifications for measuring spacecraft height above the ocean surface (+/- 10 centimeters) and significant wave height (+/- 0.5 meter). There is ample evidence that the radar altimeter, having undergone development through three earth orbit missions [Skylab, Geodynamics Experimental Ocean Satellite 3 (GEOS-3), and Seasat], has reached a level of precision that now makes possible its use for important quantitative oceanographic investigations and practical applications.

Protective effect of natural honey against acetic acid-induced colitis in rats.

AIMS: The protective effects of natural honey against acetic acid-induced colitis were investigated in rats. METHODS: Honey and glucose, fructose, sucrose, maltose mixture were administered, orally and rectally, daily for a period of 4 days. Induction of colitis was done on the third day using 3% acetic acid. Animals were killed on day 4 two hours after administration of the dose and colonic biopsies were taken for macroscopic scoring, histopathological and biochemical studies. RESULTS: Honey dose-dependently afforded protection against acetic acid-induced colonic damage. There was almost 100% protection with the highest dose (5 g/kg) used while glucose, fructose, sucrose, maltose mixture produced no significant protective effect. Also, honey prevented the depletion of the antioxidant enzymes reduced glutathione and catalase and restored the lipid peroxide malondialdehyde towards normal levels. CONCLUSIONS: Further studies are required to explore the active ingredients responsible for the antioxidant effect of honey and its therapeutic potential in humans.

The protective effect of glutathione administration on adriamycin-induced acute cardiac toxicity in rats.

Adriamycin (ADR) is a potent antitumor antibiotic drug known to cause severe cardiac toxicity. Although ADR generates free radicals, the role of these radicals in the development of cardiac toxicity is still not well understood. In the present study, we evaluated the effect of glutathione (GSH) supplementation or depletion on ADR-induced cardiotoxicity in male Wistar rats. Cardiac toxicity was induced by a single intraperitoneal injection of ADR (20 mg kg(-1)) and manifested by an increase in heart rate, blood pressure elevation, and increased serum creatine kinase (CK) and lactate dehydrogenase (LDH). The extent of lipoprotein oxidation, lipid peroxide measured as malondialdhye (MDA), total homocysteine (tHcy), lipid profile, and atherogenic index were markedly elevated, whereas cardiac GSH content was dramatically decreased in ADR rats. Pre- and co-treatment of ADR rats with GSH (5 mm kg(-1)) (ADR +GSH) markedly reduced the levels of CK, LDH, lipoprotein oxidation susceptibility, cardiac MDA, tHcy and atherogenic index, and elevated GSH levels in cardiac tissues. In contrast, GSH depletion through administration of l-buthionine-(S,R)-sulfoximine (BSO) (15 mm kg(-1)) before and after ADR injection (ADR +BSO) greatly exacerbated ADR cardiotoxicity compared to the control and ADR groups. Finally, there were also severe cardiac histopathological changes in ADR and ADR +BSO groups, which were nearly restored by GSH treatment. These results suggest that GSH inhibits ADR cardiotoxicity and might serve as a novel combination with ADR to limit free radical-mediated organ injury.

Protective effect of natural honey against acetic acid-induced colitis in rats.

AIMS: The protective effects of natural honey against acetic acid-induced colitis were investigated in rats. METHODS: Honey and glucose, fructose, sucrose, maltose mixture were administered, orally and rectally, daily for a period of 4 days. Induction of colitis was done on the third day using 3% acetic acid. Animals were killed on day 4 two hours after administration of the dose and colonic biopsies were taken for macroscopic scoring, histopathological and biochemical studies. RESULTS: Honey dose-dependently afforded protection against acetic acid-induced colonic damage. There was almost 100% protection with the highest dose (5 g/kg) used while glucose, fructose, sucrose, maltose mixture produced no significant protective effect. Also, honey prevented the depletion of the antioxidant enzymes reduced glutathione and catalase and restored the lipid peroxide malondialdehyde towards normal levels. CONCLUSIONS: Further studies are required to explore the active ingredients responsible for the antioxidant effect of honey and its therapeutic potential in humans.