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The influence of static magnetic fields with intensity of 30-50 mT on the early cleavage division of the sea urchinEchinometra mathaei was investigated. The exposure of fertilized eggs to 30, 40, and 50 mT of magnetic fields delayed the onset of early cleavage division. A delay in the first cleavage of 15, 30, and more than 60 min was caused by application of 30, 40, and 50 roT, respectively. The data also showed a significant decrease in cleaved cells for the exposed embryos. Moreover, the exposed eggs to magnetic fields showed more abnormalities compared to the control group. As the intensity of the magnetic field is increased, earlier appearances of abnormalities were observed. That is, deformed fertilization membrane appeared after only 15 min of exposure to 50 mT compared to 30 rain in 30 and 40 mT exposures and 90-105 rain in the control group. Index Terms--Embryonic development, fertilization membrane, sea urchin, static magnetic field.

Magnetization curves for normal, sickle, and beta thalasemia major erythrocytes at different hemoglobin states (normal and reduced) are discussed. The effective magnetic moment for the reduced hemoglobin molecule was estimated using VSM measurements.

Background: The mechanisms of ELF-EMFs action on the brain are still poorly understood. One of the possible explanations of these effects could be due to the increase in the intracellular Ca2+. This increase in Ca2+ may lead to a decrease in cholinergic activity. These changes in brain activities may lead to changes in motor coordination and motor learning and the possibility that calcium channel blockers might exert neuroprotective effects. Objective: To evaluate the protective effect of calcium channel blocker (Amlodipine) on deficiency in motor learning abilities of exposed mice to extremely low-frequency electromagnetic Fields ELF-EMFs (1 mT, 50 Hz). Setting: Animal House, Arabian Gulf University, Kingdom of Bahrain. Design: An Experimental Animal Study. Method: Mice were divided randomly into four groups: Group I: (Control group) 8 mice; Group II: 8 mice exposed to ELF-EMF (2 h/day) immediately before each session of training; Group III: 8 mice exposed to ELF-EMF and treated previously by calcium channel blockers (3mg/kg/day) for four weeks; Group IV: 8 mice exposed to ELF-EMF but left to rest for two weeks with no electromagnetic field exposure, then trained. Rotarod experiments were performed on the four groups. The effect of rotation speed (45,50,55,60 rpm) was tested on a 5-day course. Result: Result revealed statistically significant enhancement in the motor coordination performance in Group II, III and IV, over the five days of training, but showed an appreciable deficit in motor learning abilities for Group II. The results from Group III revealed that learning abilities for exposed mice were improved by giving the mice a therapeutic dose treatment of calcium channel blockers Amlodipine. These results indicate that the deficiency in motor learning abilities effects is partially due to the increase of the calcium levels in specific parts of mice brains, namely; hippocampus and brainstem, which was supported by an earlier study. Conclusion: Treating the mice with calcium channel blocker might prevent deficiency in motor learning abilities of exposed mice to ELF-EMF. [ABSTRACT FROM AUTHOR]