ascorbic-acid and Pseudotumor-Cerebri

Vitamins contain reactive functional groups necessary to their established roles as coenzymes and reducing agents. Their reactive potential may produce injury if vitamin concentration, distribution, or metabolism is altered. However, identification of vitamin toxicity has been difficult. The only well-established human vitamin neurotoxic effects are those due to hypervitaminosis A (pseudotumor cerebri) and pyridoxine (sensory neuropathy). In each case, the neurological effects of vitamin deficiency and vitamin excess are similar. Closely related to the neurological symptoms of hypervitaminosis A are symptoms including headache, pseudotumor cerebri, and embryotoxic effects reported in patients given vitamin A analogs or retinoids. Most tissues contain retinoic acid (RA) and vitamin D receptors, members of a steroid receptor superfamily known to regulate development and gene expression. Vitamin D3 effects on central nervous system (CNS) gene expression are predictable, in addition to the indirect effects owing to its influence on calcium and phosphorus homeostasis. Folates and thiamine cause seizures and excitation when administered in high dosage directly into the brain or cerebrospinal fluid (CSF) of experimental animals but have rarely been reported to cause human neurotoxicity, although fatal reactions to i.v. thiamine are well known. Ascorbic acid influences CNS function after peripheral administration and influences brain cell differentiation and 2-deoxyglucose accumulation by cultured glial cells. Biotin influences gene expression in animals that are not vitamin-deficient and alters astrocyte glucose utilization. The multiple enzymes and binding proteins involved in regeneration of retinal vitamin A illustrate the complexity of vitamin processing in the body. Vitamin A toxicity is also a good general model of vitamin neurotoxicity, because it shows the importance of the ratio of vitamin and vitamin-binding proteins in producing vitamin toxicity and of CNS permeability barriers. Because vitamin A and analogs enter the CNS better than most vitamins, and because retinoids have many effects on enzyme activity and gene expression, Vitamin A neurotoxicity is more likely than that of most, perhaps all other vitamins. Megadose vitamin therapy may cause injury that is confused with disease symptoms. High vitamin intake is more hazardous to peripheral organs than to the nervous system, because CNS vitamin entry is restricted. Vitamin administration into the br

Topics: Abnormalities, Drug-Induced; Animals; Ascorbic Acid; Avitaminosis; Blood-Brain Barrier; Carrier Proteins; Coenzymes; Drug Interactions; Folic Acid; Humans; Injections, Spinal; Liver; Methotrexate; Nervous System Diseases; Oxidation-Reduction; Pseudotumor Cerebri; Pyridoxine; Self Medication; Vitamin A; Vitamins

The authors present their results regarding the use of a buffered solution of glycerol 30%-sodium ascorbate 20% (GLIAS) for the treatment of brain oedema and intracranial hypertension. GLIAS was perfused intravenously in 80 patients with several types of brain oedema. In every patients serum and urinary osmolarity, diuresis, main blood and urine parameters, and ICP were monitored. Following GLIAS infusion an increase in plasma osmolarity was observed, changing the average basal value plus 13.4% after 15 min., 10.5% after 30'. At the same time there was a reduction of ICP and improvement in cerebral compliance. In each case there was a decrease in intracranial hypertension and brain oedema without significant collateral effects.

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Brain Edema; Brain Injuries; Brain Neoplasms; Buffers; Cerebral Hemorrhage; Child; Dose-Response Relationship, Drug; Female; Glycerol; Humans; Hypertonic Solutions; Infusions, Intravenous; Intracranial Aneurysm; Intracranial Pressure; Male; Middle Aged; Postoperative Complications; Pseudotumor Cerebri

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Brain Edema; Child; Child, Preschool; Drug Therapy, Combination; Female; Glycerol; Humans; Injections, Intravenous; Male; Middle Aged; Pseudotumor Cerebri