Incriase of the serotonin metabolite, 5-hydroxyindoleacetic acid, in cerebro-spinal fluid and spinal cord of bovines affected with the paraplegic syndrome

The paraplegic syndrome of bovines is a condition characterized by impairment of locomotion, hypoalgesia and finally death within 72 h. The pathogenesis of the syndrome has not been established. In the present work we determined the levels of monoamines and their metabolites in cerebro-spinal fluid and spinal cord of affected animals in order to investigate the functional state of these neurotransmitters. The content of the main metabolite of serotonin, 5-hydroxyindoleacetic acid, was elevated in the cerebro-spinal fluid and in the gray matter of the spinal cord of paraplegic bovines. Serotonin content in the spinal cord did not differ with respect to control animals, but was decreased in the cerebro-spinal fluid of affected animals. Modifications in the noradrenergic system were also observed, but were less consistent, for which reason further studies are needed. These observations indicate an increase in the turnover rate of serotonin in the paraplegic syndrome. The meaning of the described alterations is unknown at the moment

Estabilidade química do ácido homovanílico em amostras biológicas / Chemical stability of homovanilic acid in biological samples

A determinação do ácido homovanílico em amostras de urina pode ser utilizada tanto no diagnóstico laboratorial de casos de neuroblastomas, quando na monitorização biológica de exposições ocupacionais ao manganês. O presente trabalho objetivou estudar a estabilidade química deste composto, em amostras de urinas armazenadas a 4 °C e –20 °C, procurando fornecer aos laboratórios de análises clínicas e toxicológicas subsídios para um melhor controle de qualidadde analítico, especialmente tem relação à coleta, armazenamento e transporte das amostras. Os resultados deste trabalho mostraram que, na ausência de qualquer conservante, o ácido homovanílico armazenado a 4 °C ou a –20 °C é estável, pelo menos, por 25 dias em amostras de urina.