All parts of the jimsonweed plant are poisonous to horses and humans; toxicity is caused by tropane alkaloids. Symptoms of poisoning in horses include a weak, rapid pulse, dilated pupils, dry mouth, incoordination, diarrhea, convulsions, coma, and sometimes death.
Meningioma Causes. The causes of meningioma are not yet fully understood. In fact, several research studies suggest that many meningiomas develop spontaneously, or without a known cause. Sometimes, these tumors can disappear spontaneously as well. Meningiomas, like other solid tumors, develop when healthy cells undergo genetic mutations that cause them to replicate uncontrollably.
Meningiomas are benign, slow-growing tumors, classified as brain tumors, but actually growing in the three protective membranes that surround the brain (meninges). Sometimes they cause thickening or thinning of adjoining skull bones. Meningiomas do not spread to other areas of the body.