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Biomedical subjects

M L Nunes

Publications and source records attributed to M L Nunes.

At least 19 recordsLinked to original sources
PubMed2005

Assessment of the essential element and heavy metal content of edible fish muscle.

The aim of this work was to determine the concentrations of some essential and toxic elements in the muscle of ten species of commercial fish consumed in Portugal. We combined two different techniques for determination of the elements--energy-dispersive X-ray fluorescence (EDXRF) was used to quantify K, Ca, Fe, Zn, Se, Rb, and Sr and flame atomic-absorption spectrometry for analysis of Cr, Ni, Cu, Cd, Hg, and Pb. The latter technique was used because of its higher sensitivity, because these elements were not detected by EDXRF. The results obtained show a similar pattern for the trace elements. K and Ca are present at the highest concentrations in all the samples studied, from 0.6-1.3% and from 0.04-0.08%, respectively, followed by Zn, Fe, Sr, Se, and Rb. Sr is present at higher concentrations than Rb in all the species studied except meagre. Concentrations of the elements in octopus do not follow this pattern--Fe is present at a higher concentration than Zn. Low concentrations of Cr (0.66-1.5 microg g(-1)), Ni (0.11-0.24 microg g(-1)), Cd (0.01-0.08 microg g(-1)), Hg (0.49-2.74 microg g(-1)), and Pb (0.02-0.06 microg g(-1)) were observed in all the samples analysed. The concentration of Hg was highest in Helicolenus dactylopterus--5.4 microg g(-1) in one sample.

Animals↗
PubMed2005

Changes in amino acids and lipids during embryogenesis of European lobster, Homarus gammarus (Crustacea: Decapoda).

We studied the amino acid and lipid dynamics during embryogenesis of Homarus gammarus. Major essential amino acids (EAA) in the last stage of embryonic development were arginine, lysine and leucine; major nonessential amino acids (NEAA) were glutamic acid, aspartic acid, valine and glycine. The highest percent of utilization occurred in respect to EAA (27.8%), mainly due to a significant decrease (p<0.05) of methionine (38.3%) and threonine (36.0%). NEAA also decreased significantly (p<0.05, 11.4%), namely serine (38.1%), tyrosine (26.4%) and glutamic acid (25.7%). In contrast, the free amino acid content increased significantly (p<0.05) during embryonic development, especially the free nonessential amino acids (FNEAA). In the last stage, the most abundant FNEAA were glycine, proline, alanine and taurine, and the major free essential amino acids (FEAA) were arginine, lysine and leucine. Lipid content decreased significantly (p<0.05) during embryonic development. A substantial decrease in all neutral lipid classes was observed (>80% of utilization). Major fatty acids were 16:0, 18:0, 18:1n-9, 18:2n-6, 18:3n-3, 20:5n-3 and 22:6n-3. Unsaturated (UFA) and saturated fatty acids (SFA) were used up at similar rates (76.5% and 76.3%, respectively). Within UFA, monounsaturates (MUFA) were consumed more than polyunsaturates (PUFA) (82.9% and 67.5%, respectively).

Amino Acids↗
PubMed2005

Changes in tissue biochemical composition and energy reserves associated with sexual maturation in the ommastrephid squids Illex coindetii and Todaropsis eblanae.

The aim of this study was to investigate the biochemical changes that occur during sexual maturation of the squids Illex coindetii and Todaropsis eblanae. In both species, amino acids and protein content increased in the gonad throughout maturation, but the allocation of these nitrogen compounds from the digestive gland and muscle was not evident. A significant (P < 0.05) increase in the content of lipids and fatty acids was observed in the gonad and digestive gland. It seems that both species take energy for egg production directly from food, rather than from stored products. Analyses for cholesterol revealed a significant (P < 0.05) increase in the gonad, and the lipid content differences between species are potentially related to different feeding ecologies. The glycogen reserves in the gonad increased significantly (P < 0.05), suggesting that glycogen has an important role in the maturation process. It was evident that sexual maturation had a significant effect upon the gonad energy content, but because the energy variation in the digestive gland and muscle was nonsignificant (P > 0.05), there was no evidence that storage reserves are transferred from tissue to tissue.

Amino Acids↗
PubMed2004

Biochemical dynamics of spermatogenesis and oogenesis in Eledone cirrhosa and Eledone moschata (Cephalopoda: Octopoda).

The effect of spermatogenesis and oogenesis on protein, lipid, glycogen, cholesterol and energy contents, total amino acid and fatty acid profiles of Eledone cirrhosa and Eledone moschata tissues (gonad, digestive gland and muscle) was investigated. A significant (p<0.05) increase in the amino acids and protein content of the gonad throughout sexual maturation (namely in oogenesis) was observed, but the allocation of these nitrogen compounds from the digestive gland and muscle was not evident. The major essential amino acids (EAA) in the three tissues were leucine, lysine and arginine. The major nonessential amino acids (NEAA) were glutamic acid, aspartic acid and alanine. A significant increase in lipid and fatty acid contents of gonad and digestive gland was observed. There was also little evidence of accumulated lipid storage reserves being used for egg production. It seems that for egg production Eledone species use energy directly from food, rather than from stored products. Most of saturated fatty acid (SFA) content of the three tissues was presented as 16:0 and 18:0, monounsaturated fatty acid (MUFA) content as 18:1 and 20:1 and polyunsaturated fatty acid (PUFA) content as 20:4n-6, 20:5n-3 and 22:6n-3. Cholesterol and glycogen contents significantly increased in gonad and digestive gland throughout maturation while the muscle revealed no obvious pattern. If Eledone's component sterols are of a dietary origin, a considerable variation in the cholesterol content between species might be expected on the basis of the sterol composition of their prey. Although spermatogenesis and oogenesis had a significant effect (p<0.05) in gonad and digestive gland energy content, the biochemical composition of digestive gland and muscle may not be primarily influenced by sexual maturation, but rather by other biotic factors such as feeding activity, food availability, spawning and brooding.

Animals↗
PubMed2002

Nutrition and brain function: a multidisciplinary virtual symposium.

A few months ago, the Brazilian Society for Neuroscience and Behavior (SBNeC) promoted a "virtual symposium" (by Internet, under the coordination of R.C.A. Guedes) on "Nutrition and Brain Function". The discussions generated during that symposium originated the present text, which analyzes current topics on the theme, based on the multidisciplinary experience of the authors. The way the brain could be non-homogeneously affected by nutritional alterations, as well as questions like early malnutrition and the development of late obesity and hormone abnormalities were discussed. Also, topics like the role of essential fatty acids (EFAs) on brain development, increased seizure susceptibility and changes in different neurotransmitters and in cognitive performance in malnourished animals, as well as differences between overall changes in nutrient intake and excess or deficiency of specific nutrients (e.g. iodine deficiency) were analyzed. It was pointed out that different types of neurons, possibly in distinct brain structures, might be differently affected by nutritional manipulation, including not only lack-but also excess of nutrient intake. Such differences could help in explaining discrepancies between data on humans and in animals and so, could aid in determining the basic mechanisms underlying lesions or changes in brain function and behavior.

Brain↗
PubMed2001

Cerebral aneurysmal dilatation in an infant with perinatally acquired HIV infection and HSV encephalitis.

Although most children with human immunodeficiency virus (HIV) infection have neurological dysfunction, in childhood the incidence of symptomatic cerebrovascular disease is low. Cerebral aneurysmal arteriopathy in childhood AIDS has been reported in the past and considered to have a relatively long latency following the primary infection. We report a 1 month-old infant with congenitally acquired HIV infection, and herpes encephalitis; she presented a sudden cardiorespiratory arrest followed by coma and was found to have a giant saccular aneurysm of the left basilar artery. Literature review showed that cerebral aneurysmal artheriopathy is an unusual manifestation in newborns and infants and this case is possibly the youngest patient reported with aneurysma, herpes encephalitis and AIDS. The role of HIV and herpes simplex infections in the pathogenesis of this lesion is discussed.

Encephalitis, Herpes Simplex↗
PubMed2001

[Neurochristopathy in the differential diagnosis of newborn's apnea: case report].

OBJECTIVE: to include neurocristopathy on the etiological workup of neonatal apneas and discuss the importance of polysomnography in this diagnosis. METHOD: case report and critical review of the literature. RESULTS: we report on a newborn that presented respiratory failure in the first hours of life associated to abdominal distention. Continuous ventilatory support was necessary, and the respiratory distress increased during sleep. After polysomnographic confirmation of hypoventilation the newborn was submitted to neuroradiolgic tests and colon byopsy, positive to Hirschsprung's disease. CONCLUSION: Neurocristopathy syndrome can have many different clinical expression, and sometimes the syndrome can be misdiagnosed. Polysomnography confirms central hypoventilation. This diagnosis should be considered in the newborn's persistent apnea workup.

Hirschsprung Disease↗
PubMed2001

[Seizures in the neonatal period]

OBJECTIVE: To characterize and differentiate neonatal seizures from those that occur at different ages, based on a critical assessment of the available literature and also on the authorś clinical experience. SOURCES: Literature review, including up-to-date and classical studies that helped us to better understand clinical, neurophysiological and physiopathological aspects related to seizures in the newborn. SUMMARY OF THE FINDINGS: The authors present clinical and electroencephalographic characteristics of neonatal seizures, discuss their classification, treatment and prognosis. CONCLUSIONS: Neonatal seizures have a distinct clinical pattern, which justifies the necessity of an appropriate classification. The etiology is predominantly symptomatic and multifactorial; the treatment should follow a routine protocol, and the prognosis seems to be closely related to etiology.

Journal Article↗
PubMed2000

Duration of rhythmic EEG patterns in neonates: new evidence for clinical and prognostic significance of brief rhythmic discharges.

OBJECTIVE: This study aimed at identifying the characteristics - especially the duration - of rhythmic discharges in neonatal EEG, and their association with clinical neonatal problems. Specifically, we aimed at testing the diagnostic and prognostic validity of using 10 s as minimal duration for defining electroencephalographic seizures. DESIGN AND METHODS: The polysomnographies of 340 neonates were reviewed, and episodes of rhythmic discharges were identified, analyzed, and quantified. The study sample was divided into 3 groups: one in which the maximal duration of rhythmic discharges was shorter than 10 s (brief rhythmic discharges, BRD), a second one in which there were rhythmic discharges longer than 10 s (long rhythmic discharges, LRD), and finally a group in which no rhythmic discharge was found (No-RD). These 3 groups of subjects were compared for the baseline and outcome clinical data. RESULTS: From the 340 neonates studied, 210 did not present any form of rhythmic discharge, 67 (19. 7%) had only BRD episodes, and 63 (18.5%) had at least one LRD episode. Prevalence of rhythmic discharges was low among healthy full term newborns, and was significantly higher among preterm and high-risk newborns. Electrophysiological characteristics of rhythmic discharges did not differ between healthy neonates and high-risk ones. Accompanying clinical manifestations were present in 26.3% of the LRD group, but also in 15.9% of the BRD group. The presence of BRD was significantly associated with leukomalacia and with hypoglycemia in the cross-sectional analysis of baseline data, and with an increased risk for abnormal neurodevelopmental outcome after a mean follow-up period of 47 months (adjusted relative risk=4.90, P<0.01). CONCLUSIONS: The present data demonstrate an association between BRD and clinical history of hypoxic-ischemic encephalopathy, especially when complicated by leukomalacia, and also with a prognosis of increased risk for abnormal neurodevelopmental outcome. The clinical and prognostic significance of isolated BRD justifies the need to include these brief episodes in future studies of neonatal seizures.

Brain↗
PubMed2000

Polysomnography in neonatal seizures.

Seizures are one of the most frequent problems in the neonatal period, and are frequently associated with high mortality and morbidity rates. On the other hand, neonatal seizures may represent a first or even the only sign of central nervous system dysfunction. However, establishing the diagnosis of neonatal seizures poses several problems, and clinical observation is not sufficient in many cases. Neonatal polysomnography is a valuable tool both in the diagnostic and in the prognostic assessment of neonatal seizures. The present text reviews some technical aspects related to neonatal polysomnographies, and its usefulness in the area of suspected neonatal seizures. Moreover, some questions are raised regarding rhythmic discharges and their significance as a possible ictal and interictal epileptic pattern in the neonate.

Brain↗
PubMed2000

Differences in the dynamics of frontal sharp transients in normal and hypoglycemic newborns.

OBJECTIVE: This study focuses on the characteristics of frontal sharp transients (FST), a normal variant of neonatal EEG, in newborns with hypoglycemia. METHODS: The EEG from 20 newborns with symptomatic hypoglycemia were compared with a control group of normal newborns matched by conceptional age. The dynamics of these transients were evaluated concerning sleep stages. The density, type and bilateral synchrony of FST were also calculated. The results were compared in the two groups by Student's t test. RESULTS: When compared with controls, hypoglycemic newborns have increased density of frontal sharp transients in all sleep stages but less bilateral synchrony (P<0.05). FST density was even higher in small for gestational age newborns. CONCLUSIONS: The data suggests that normal patterns of neonatal EEG as FST can be influenced by systemic disturbances.

Electroencephalography↗
PubMed2000

Malnutrition increases dentate granule cell proliferation in immature rats after status epilepticus.

PURPOSE: Nutritional insults early in life have a profound and often permanent effect on the development of the central nervous system. A direct relationship between malnutrition and epilepsy has not been established; however, it is believed that inadequate nutrition may predispose the brain to seizures. This study was designed to determine whether neonatally malnourished rats are different from nourished rats in terms of flurothyl seizure susceptibility at postnatal day (P)15, in the behavioral manifestations of seizures, and in status epilepticus-induced hippocampal injury. METHODS: Sprague-Dawley rat pups were maintained on a starvation regimen from P2 until P17. Age-matched control rats were not exposed to starvation. At P15, all animals were exposed to flurothyl-induced status epilepticus. At P17, the rats received a single injection of bromodeoxyuridine (50 mg/kg intraperitoneal) to determine the extent of genesis of new cells in the dentate gyrus. At P18, the rats were killed, and the brains were processed for histology and immunohistochemistry. RESULTS: Preliminary analysis indicates that early malnutrition did not modify flurothyl seizure susceptibility or the behavioral manifestations of seizures at P15. Histological assessment did not reveal any evidence of hippocampal cell loss after status epilepticus in either group. Malnutrition per se induced an increase in the genesis of new cells in the anterior dentate granule cell layer. Although exposure to status epilepticus augmented the expression of new cells in the dentate gyrus in both groups, this expression was more pronounced in the malnourished group. CONCLUSIONS: The findings suggest that malnutrition early in life alters dentate plasticity but not the susceptibility to flurothyl seizures. Although status epilepticus can increase the expression of new cells in the dentate gyrus in immature rats, malnutrition followed by status epilepticus further increases dentate granule cell proliferation.

Animals↗
PubMed1999

Congenital intramedullary tumor with neonatal manifestations.

The authors report on a 45-day-old boy with a congenital intramedullary tumor with clinical manifestations since birth. Neurologic examination disclosed severe bilateral lower-limb hypotonia and diplegia, with exacerbated deep tendon reflexes and clonus associated with severe pain at manipulation. Further evaluation of this patient included screening for infections, computed tomographic scan, myelography, and somatosensory evoked potentials. The definite diagnosis was a solid holocord astrocytoma. This report discusses a rare disorder in the neonatal period and makes other medical practitioners aware of this diagnosis. Previously published literature is also reviewed.

Astrocytoma↗
PubMed1999

Subacute sclerosing panencephalitis. Clinical aspects and prognosis. The Brazilian registry.

Subacute sclerosing panencephalitis (SSPE) is an inflammatory neurodegenerative disease related to the persistence of measles virus. Although its frequency is declining because of measles eradication, we still have some cases being diagnosed. With the aim to describe epidemiological aspects of SSPE in Brazil, we sent a protocol to Child Neurologists around the country, 48 patients were registered, 27 (56%) were from the southeast region, 34 (71%) were male and 35 (73%) white, 27 (56%) had measles, 9 (19%) had measles and were also immunized, 7 (14%) received only immunization, 1 patient had a probable neonatal form. Mean time between first symptoms and diagnosis was 12 months (22 started with myoclonus or tonic-clonic seizures, 7 (14%) with behavioral disturbances); 36 patients (75%) had EEG with pseudoperiodic complexes. Follow up performed in 28 (58%) patients showed: 12 died, 2 had complete remission and the others had variable neurological disability. Our data shows endemic regions in the country, a high incidence of post-immunization SSPE and a delay between first symptom and diagnosis.

Adolescent↗
PubMed1997

Polysomnographic quantification of bioelectrical maturation in preterm and fullterm newborns at matched conceptional ages.

We analyzed the relationship between normal neonatal EEG features and gestational age and conceptional age, and evaluated the normal aspects of EEG maturation in preterm babies compared to term babies. We report 46 newborns, divided into two groups. Group I consisted of 11 newborns with gestational age between 30 and 32 weeks, followed with weekly polysomnograms until they reach 42 weeks' conceptional age. Group II (control) consisted of 35 newborns with gestational ages of 34 weeks (n = 5), 36 weeks (n = 10), 38 weeks (n = 10) and 40 weeks (n = 10) evaluated with one polysomnogram in their first 24-48 h of life. In each examination one 5 min epoch in REM and NREM sleep was analyzed to quantify the number of delta brushes, the presence of frontal and temporal sharp transients, the presence of delta frontal rhythmic activity, the grade of concordance between EEG patterns and sleep stages, the percent of interhemispheric synchrony and the duration of interburst interval. The age dependent variability of the EEG patterns was evaluated during the subsequent weeks with group comparisons at weeks 34, 36, 38 and 40. Our results show that the number of delta brushes and the duration of the interburst interval decrease as gestational and conceptional age increase. The percent of interhemispheric synchrony increases with gestational and conceptional age. The presence of frontal sharp transients and delta frontal rhythmic activity suggest that the newborn is fullterm. The presence of temporal sharp transients suggest a preterm newborn. The degree of concordance between behavioral sleep patterns and EEG was more helpful in recognizing sleep stages than in estimating gestational or conceptional age. Although the EEG patterns were comparable between the groups at the same age, analyses of the behavioral patterns of concordance in NREM sleep showed that newborns in Group I had a more immature behaviour than newborns in Group II. Our results also suggest that extrauterine life of preterm babies does not seem to accelerate EEG maturation but may influence the acquisition of behavioral patterns during NREM sleep.

Age Factors↗
PubMed1997

Vigabatrin in refractory childhood epilepsy. The Brazilian Multicenter Study.

Children, 47, with various types of severe drug-resistant epilepsy were entered into a prospective, add-on, open trial with vigabatrin. Patients with West syndrome and idiopathic generalized epilepsies were excluded. Seven children had the drug withdrawn, five because of increase in seizure frequency and two because of adverse effects. Drug efficacy, measured according to seizure type, showed a 100% decrease in seizure frequency in 18.6% of partial seizures and 17.3% of the generalized seizures. There was a higher than 50% decrease in 39.5% of partial and 60.8% of generalized seizures, and less than 50% decrease or increase in seizure frequency in 41.8% and 21.8% of partial and generalized seizures, respectively. Vigabatrin mean dosage during phase 3 was 63.6 mg/kg per day (S.D. = 30.5), ranging from 19.3 to 110.5 mg/kg per day. Parametric statistical analysis (Student's t-test) of seizure frequency between phases 1 and 3 showed a significant decrease in seizure frequency for partial (P = 0.022), and generalized seizures (P < 0.0001). Drug-related adverse effects were observed in 18/47 cases (38.3%), consisting mainly of irritability, hyperactivity, dizziness, somnolence and gastrointestinal symptoms.

Adolescent↗
PubMed1997

[Phasic activity of REM sleep in newborns and infants and its relationship with apnea episodes].

When the apnea hypothesis turned to be an explanation for sudden infant death syndrome (SIDS) many authors tried to find if near-miss or apparent life-threatening events (ALTE) could be markers of SIDS. It was suggested that phasic REM activity is associated with increased respiratory neuron activity and prevents prolonged apnea in near-miss SIDS. In a previous retrospective study with newborns we did not confirm these results, nevertheless we had several babies with serious neurological disturbances. The aim of this study was to verify the relationship of phasic activity (rapid eyes movement and sucking bursts) with both apneic and non-apneic epochs during REM sleep. We studied 86 children referred for evaluation because they presented an ALTE during sleep or apneas. The subjects were divided in three groups by age (newborns, n = 31; 1-6 months, n = 48; and > 6 < 12 months, n = 7). They were all submitted to a clinical and neurological evaluation in order to detect possible etiological factors to the apneic episode. The polysomnograms (PS) consisted of EEG, submental EMG, electro-oculogram and cardiorespiratory monitoring. The records were made between 11 am and 15 pm for 2 or 3 hours. The electrodes were disposed in the 10-20 system. During one five-minutes epoch of REM sleep we verified the incidence of phasic activity (rapid eyes movement or sucking bursts) time locked to apneic episodes and compared with a similar duration non-apneic epoch. To evaluate the relationship of phasic activity with apneic and non-apneic eopchs we compared the incidence of rapid eyes movements and sucking bursts in each group. Our results showed that phasic activity of REM sleep (sucking bursts) seems to be more frequent in newborns in non-apneic epochs (p < 0.05). Between 1-6 months the number of rapid eyes movements were more frequent in non-apneic epochs (p = 0.001). In conclusion our findings suggest that phasic activity of REM sleep seems to be more evident in nonapneic epochs during the first six months of life. Although central apneas may have their origin in an intrinsic disturb of the respiratory control center they may be influenced by the phasic activity of REM sleep. The rapid eyes movements and sucking bursts may have a protection effect against apneas at least in the first 6 months of life. which is the predominant period for SIDS. We suggest that the excitatory driving related to generation of phasic activity in REM sleep may block or atenuate tonic inhibition of respiratory motoneuron and avoid apnea. It is still open for discussion the possible relation between failure of this protective mechanism and SIDS.

Female↗