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4-Hydroxybutyric aciduria
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
Other compounds found in the urine of patients include dicarboxylic acids, which might suggest a disorder of fatty acid oxidation [35]. 4-Hydroxybutyric acid is, after all, a short chain fatty acid. They could result from secondary inhibition of mitochondrial fatty acid oxidation. 4,5-dihydroxyhexanoic acid identified in the urine of these patients [35] has not been found in other metabolic diseases and so may be a specific marker for this disease. It could arise from the condensation of a 2-carbon moiety with succinic semialdehyde. The occurrence of 3-hydroxypropionic acid and glycine in the urine of some patients might suggest a diagnosis of a disorder of propionate metabolism. Identification of the key compound, 4-hydroxybutyric acid, should avoid any confusion. Glycine would be a product of glycolic acid, which can be formed from β-oxidation of 4-hydroxybutyric acid [36].
Bowel obstruction following ingestion of superabsorbent polymers beads: literature review
Published in Clinical Toxicology, 2022
Weniko Caré, Laurène Dufayet, Nathalie Paret, Jacques Manel, Hervé Laborde-Casterot, Ingrid Blanc-Brisset, Jérôme Langrand, Dominique Vodovar
Three children developed seizures related to hyponatremia caused by vomiting [25,32,34]. There is no evidence to suggest that SAPs could be responsible for neurological toxicity. The onset of neurological toxicity (decreased consciousness or even coma) following the ingestion of colored BindeezTM beads (Moose Enterprise Pty Ltd., Victoria, Australia) and Aqua DotsTM (Spin Master Ltd., Toronto, Canada) has been reported [54]. However, these beads are not a superabsorbent polymer-made product. They were sold as toys that allow the creation of multi-dimensional shapes after melting the beads in contact with water. Toxicological analysis showed γ-hydroxybutyric acid in the poisoned children’s urine, leading to the discovery that the manufacturer had substituted 1,5-pentandiol with 1,4-butanediol (a precursor of γ-hydroxybutyric acid) for cost reasons [55].
Ganaxolone treatment for epilepsy patients: from pharmacology to place in therapy
Published in Expert Review of Neurotherapeutics, 2021
Simona Lattanzi, Antonella Riva, Pasquale Striano
Like many other GABA-enhancers, GNX has been shown to exacerbate spike-wave discharges in pentylenetetrazol, γ-hydroxybutyric acid, and genetic animal models of absences [27]. However, it suppressed discharges when microinjected into the perioral region of the primary somatosensory cortex in WAG/Rij rats [34]. As the pathogenesis of absence seizures is associated with GABA hyperfunction rather than hypofunction [47], the worsening of absence seizures may be due to the enhancement of the GABA-ergic inhibition at the level of thalamic relay neurons. The suppression of spike-wave discharges following cortical GNX injection could be, instead, responsible for the activation of an inhibitory circuit within the cortical area with subsequent inhibition of excitatory projections from the cortex to the thalamus [34]. Of note, the neocortex can also be involved: an increase in synaptic excitability mediated by NMDA receptors has been observed in neurons located in neocortical deep layers in the experimental model of absence seizures, and this mechanism may play a role in initiating and maintaining generalized spike and wave discharges in vivo [48].
Interpreting γ-hydroxybutyrate concentrations for clinical and forensic purposes
Published in Clinical Toxicology, 2019
Francesco Paolo Busardò, Alan Wayne Jones
γ-Hydroxybutyric acid (4-hydroxybutyric acid, GHB) is a straight chain carboxylic acid comprised of four carbon atoms and a single hydroxyl (–OH) group bonded to C-4 (Figure 1). Its molecular weight is 104.1 g/mol. The acid (–COOH) and alcohol (–OH) functional groups in close proximity mean that GHB can undergo intramolecular esterification. In aqueous solution, depending on time, temperature, and pH, GHB is converted to the corresponding cyclic ester (γ-butyrlolactone, GBL), as depicted in Figure 1. Accordingly, at low pH (acid catalyzed) the cyclization is favored and GHB is dehydrogenated to yield GBL. In basic media (high pH) the reverse reaction occurs and GBL is hydrolyzed back to GHB [1].