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 named according to their location (Fig 1) and cause various symptoms: 1  Convexity meningiomas: grow on the surface of the brain. They may not produce symptoms until they reach a large size. 2  Falx and parasagittal meningiomas: grow from the dura fold that runs between the left and right sides of the brain.