Chapters authored
Autoimmune Epilepsy: New Development and Future Directions
In recent years, there has been accumulating evidence to support an autoimmune etiology for some patients with drug-resistant seizures, typically in the context of an antibody-mediated encephalopathy; any seizure disorder that may be caused by pathogenic autoantibodies, are an example of autoimmune epilepsy. Autoimmunity is characterized by loss of immune tolerance that causes the destruction of cells and tissues. The largest complex histocompatibility system has had a strong association with autoimmune disease, although certain genes encoding cytokines and co-stimulatory molecules increase genetic susceptibility. In spite of having scientific advances in this research area, the conditions underlying mechanisms are unknown.Goal: this chapter aims to present in synthesized form, the genetic, immunological, and environmental factors role in the autoimmunity to epilepsy, as well as the therapeutic approach that has been used to control seizures, mainly where there is a suspected anti-neuronal-antibodies circulation. Methods: a review of the work achieved during the last years in patients with this condition provides information and experience in the diagnosis and treatment of this epilepsy type. For this, a systematic search of PUBMED is conducted using the search terms “autoimmune and epilepsy, auto antibodies and epilepsy, NMDA and epilepsy, AMPA and epilepsy, and GAD and epilepsy.” The list of identified articles was complemented by additional searches for relevant articles in the reference section of the publications captured by the initial search.
Part of the book: Seizures
Revisiting Pharmacokinetics and Pharmacogenetics of Methadone in Healthy Volunteers
Methadone acts as a μ opioid agonist, a serotonin and norepinephrine reuptake inhibitor, and a noncompetitive N-methyl-D-aspartate receptor antagonist. These actions altogether are responsible for its efficacy in the management of chronic pain. It is available as a racemic mixture of (R)- and (S)-methadone, both being stereoisomers responsible for its analgesic effect. Methadone elimination occurs mainly through metabolism in the liver by CYP3A4, CYP2B6, and CY2C19 and to a lesser extent by CYP2D6 and in the intestine by CYP3A4. The relative intestinal content of CYP2B6 and CY2C19 is unknown but it seems that CYP2B6 is not present at the intestine. CYP3A4, CYP2B6, and CYP2C19 convert methadone mainly into 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine(EDDP). CYP2B6 and CYP2C19 are stereoselective to S- and R-enantiomer, respectively. The pharmacokinetic study carried out in healthy volunteers by our research group confirmed that MTD undergoes recirculation via gastric secretion and intestinal reabsorption and revealed that the drug is extensively metabolized in the liver but intestinal metabolism is not only relevant but also stereoselective. Polymorphisms of the CYP2B6 and CYP2C19 isoenzymes and their relationship with the pharmacokinetics of MTD were also assessed.
Part of the book: Drug Discovery and Development