RESUMO
The validation of the analytical technique for the determination of polyamines in cerebral tissue using HPLC based on o-phthalaldehyde post-column derivatization is described. The polyamines were separated in a LiChrospher100 RP18 column. Elution gradient was formed with two mobile phases: A (sodium acetate 0.1 M + sodium octanesulphonate 0.01 M, pH = 4.5) and B (sodium acetate 0.2 M + sodium octanesulphonate 0.01 M)/acetonitrile (10:3), pH = 4.5) in a 1.2 ml/min flow rate. The derivative eluent was monitored by fluorescence (excitation, 345 nm; emission, 455 nm). Besides excellent linearity (putrescine, r = 0.9816; spermidine, r = 0.9920; spermine, r = 0.9901), the technique demonstrated intra and inter-day precision (< 20 percent) as well as recovery (spermidine = 92.56 percent; spermine = 84.47 percent). Quantification limits were 0.22 pM for putrescine, 76.44 pM for spermidine and 51.44 pM for spermine. The method demonstrated to be robust, simple and highly reproducible for polyamine determination in tissues.
A validação técnica analítica para determinação de poliaminas em tecido cerebral utilizando cromotografia líquida de alta eficiência (HPLC) e derivação pós-coluna com o-ftaldialdeído é descrita. A separação das poliaminas deu-se em coluna LiChrospher 100 RP18. O gradiente de eluição foi formado por duas fases móveis A (acetato de sódio 0,1M + octanossulfonato de sódio 0,01 M) e B (acetato de sódio 0,2 M + octanossulfonato de sódio 0,01 M)/acetonitrila (10:3), fluxo de 1,2 ml/min. O eluente foi monitorado por fluorescência (excitação, 345 nm; emissão, 455 nm). Além da excelente linearidade (putrescina, r = 0,9816; espermidina, r = 0,9920; espermina, r = 0,9901), a técnica demonstrou adequada precisão intra e interdia (< 20 por cento) e recuperação (espermidina = 92,56 por cento; espermina = 84,47 por cento). Os limites de quantificação foram 0,22 pM para putrescina, 76,44 pM para espermidina e 51,44 pM para espermina. O método demonstrou ser consistente, simples e altamente reprodutível para a determinação proposta.
RESUMO
The present study investigated the effects of protein malnutrition and environmental stimulation on biochemical and behavioral parameters in rats. The concentrations of polyamines in the frontal cortex, striatum, and hippocampus, as well as plasma corticosterone levels, were measured. The exploratory behavior was analyzed using the elevated plus-maze (EPM) test. Rats received either 16 percent (well-nourished - W) or 6 percent (malnourished - M) protein diets and were divided into stimulated or non-stimulated groups. Malnutrition increased corticosterone levels and decreased plasma protein and anxiety. Non-stimulated rats tested in the EPM had increased corticosterone levels and decreased frontal cortex, striatum and hippocampus protein and polyamines contents. Stimulation decreased open arm entries in the EPM in M animals and increased closed arm entries in the W ones. Stimulation increased frequency and time spent in risk-assessment behaviors. These results suggest that both malnutrition and EPM testing are distressing situations, as indicated by increased corticosterone levels. These results are consistent with lower anxiety and/or higher impulsiveness in M animals.
RESUMO
There is evidence that the auditory evoked potential (AEP) is altered by malnutrition both in laboratory animals and in humans. The objective of the present study was to determine whether changes in the AEP caused by malnutrition could be reversed by nutritional rehabilitation and sensorymotor and environmental stimulation during hospitalization. Six children aged 5-33 months with severe malnutrition (kwashiorkor, marasmus and marasmic-kwashiorkor) were admitted to the Pediatric Ward of a University Hospital. Normal age and sex-matched children from the hospital day-care center were enrolled as a control group. The AEP was tested in an electrically and acoustically isolated room using a Nicolet CA 2000 microcomputer. Clicks of 90; 80; 70 and 60 dBn HL were presented through earphones. The results suggest that malnutrition leads to an increase in wave I latencies in patients with marasmus, and in waves I, III and V in those with kwashiorkor or marasmic-kwashiorkor type at 90 dB HL. At discharge, all but one patient with kwashiorkor showed reduced latencies of waves I, III and V compared to the values on admission. Despite the small sample, these preliminary results pointed out that the process of sensory stimulation used in our study in a properly directed, systematic and individualized manner showed encouraging results in terms of AEP recovery in these children.