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Long-term potentiation (LTP) induced in the lateral entorhinal cortex by theta-patterned tetanic stimulation of the piriform cortex was analyzed in the isolated guinea pig brain maintained in vitro. Monosynaptic excitatory postsynaptic potentials (EPSPs) evoked by stimulation of the piriform cortex are composed of an early and late component selectively blocked by non-N-methyl-D-aspartate (non-NMDA) and NMDA receptor antagonists, respectively. LTP induction was dependent on NMDA receptor activation, being blocked by perfusing the preparation with 2-amino-5-phosphonovalerate (AP-5). LTP was expressed through synaptic enhancement of both early non-NMDA and late, possibly NMDA receptor-mediated responses.

In 10 children with cystic fibrosis and persisting steatorrhoea, supplementation with taurine (30-40 mg/kg/day) was given for two months as an adjunct to the usual pancreatic enzyme treatment. A three day fat and energy balance was performed in patients with cystic fibrosis, before and after the supplementation, and in seven healthy controls who did not receive taurine. Faecal fat was measured by a gravimetric method and stool energy was determined using a bomb calorimeter. Patients with cystic fibrosis, before and after taurine, and healthy controls received the same fat and energy intake (calculated by a dietitian). In patients with cystic fibrosis taurine did not produce any improvement of steatorrhoea (mean (SD) faecal fat 8.7 (3.3) v 11.2 (7.0) g/day, respectively before and after the supplementation), of faecal energy loss (0.978 (0.468) v 1.133 (0.539) MJ/day), of faecal fat expressed as percent of fat intake (13.4 (5.6) v 15.1 (9.8)%), and of faecal energy expressed as percent of energy intake (9.9 (3.6) v 11.2 (5.7)%). Healthy controls had significant lower fat (3.5 (2.3) g/day) and energy 0.576 (0.355) MJ/day faecal losses. In conclusion, taurine failed to decrease significantly fat and energy losses. Our study does not support the use of taurine supplementation in the nutritional management of cystic fibrosis.

The role of the reticular thalamic nucleus (RTN) in pacing rhythmic cortical activities subserving spike-waves (SW) discharges has been investigated in rats. Intracellular recordings from thalamic slices in vitro demonstrated that RTN neurons from control animals possess a set of Ca2+/K+ membrane conductances which enable them to produce rhythmic oscillatory activities. In vivo, studies of Ca(2+)-conductance blockade by intrathalamic injections of Cd2+ were performed on 24 callosotomized Wistar rats displaying spontaneous SW discharges, bred at the Centre de Neurochimie, Strasbourg. A significant decrement in ipsilateral SW activity was consistently observed in all RTN-injected animals 40 min after Cd2+ injection. By contrast, animals which received Cd2+ injection into the ventroposterior complex (VP) showed only small changes in ipsilateral SW. It is concluded that Ca(2+)-dependent oscillatory properties of the RTN are critical for the expression of genetically determined SW discharges in the Wistar model.

The viability and general electrophysiological properties of the limbic system in the adult mammalian brain isolated and maintained in vitro by arterial perfusion are described. The isolated brain preparation combines the advantages of intact synaptic connectivity and accessibility of different areas of the encephalic mass with those of the in vitro approach, i.e., stability and control of the ionic environment. Extracellular field potential as well as intracellular recordings were performed at different levels in the limbic system of isolated adult guinea pig brains. The results demonstrate that in the piriform, entorhinal, and hippocampal cortices, the intrinsic electrical properties of individual cells as well as the spontaneous and evoked electrical activity in the neuronal ensembles they comprise, were virtually identical to those observed in vivo. The properties of the limbic system loop were determined.

Long-term potentiation (LTP) was investigated in the mammalian entorhinal cortex by using two in vitro preparations, the isolated brain and the entorhinal cortex slice. Hebbian and non-Hebbian types of LTP appear to be present in layer II entorhinal cortex cells as demonstrated using two protocols: (i) tetanic stimulation of the piriform-entorhinal cortex afferent pathway to generate homosynaptic potentiation and (ii) postsynaptic subthreshold rhythmic membrane potential manipulation not paired to presynaptic activation, which gives rise to non-Hebbian LTP. The induction and the expression of both types of LTP were found to be dependent on activation of N-methyl-D-aspartate receptors as shown by their sensitivity to the receptor agonist D-2-amino-5-phosphonovalerate. This is in contrast to LTP in the hippocampus [Zalutsky, R. A. & Nicoll, R. A. (1990) Science 248, 1619-1624], where LTP is expressed by quisqualate receptors. Since, in the entorhinal cortex, LTP is linked to a selective increase of the N-methyl-D-aspartate-receptor-mediated synaptic responses, this enhancement is most likely due to postsynaptic factors.

Metabolic balances were carried out in nine preterm very-low-birth-weight (VLBW) infants, five of whom were fed on expressed breast milk and four on a preterm formula. In 39 stool samples from these infants, there was a very close relationship between the fecal fat and the fecal water (r = -0.95; p less than 0.001), independent of the type of feed. This relationship was present over a very wide range of fat and water contents. Validation experiments confirmed the reproducibility and reliability of this relationship. The correlation is clinically and experimentally so close that measurement of stool water by freeze-drying a sample is an accurate indirect measure of fecal fat in VLBW infants when the daily stool weight was known.

We performed metabolic balance studies in 77 preterm infants fed on human milk or adapted formulas, to determine the renal solute load and compared it with the potential renal solute load estimated by the composition of the diet or the urine according to Ziegler's, Bergman's, and Shaw's calculations. The renal solute load found in preterm infants was lower than that observed in young full term infants. Although all calculations predicted the renal solute load well, the equation proposed by Ziegler and Fomon from dietary protein and electrolyte load appears to be the simplest to calculate renal solute load accurately in preterm infants.

Protein, fat and carbohydrate absorption in preterm infants fed on human milk or formulae are reviewed. Even in the most premature infants absorption of protein is satisfactory. Nitrogen net absorption is about 85-90% of intake and results slightly lower with human milk than with formulae. The lower apparent digestibility of human milk is probably due to the poorly degraded IgA immunoglobulins and the rapid transit time. Lactose is well tolerated by the preterm infants despite the low lactase activity at birth. Glucose polymers, which have a low osmotic activity and are suitable for increasing carbohydrate intake of formulae, are well absorbed probably for the activity of salivary amylase and brush border glucoamylase, which have been shown to be well developed at birth. Premature infants absorb fat poorly. This malabsorption that increases with the lowering of gestational age is due to low pancreatic lipase activity and to low intraluminal concentration of bile salts. Due to its bile stimulated lipase activity, non-heat-treated human milk used at least in part is an effective method to improve fat absorption in preterm infants. Faecal energy determined using a calorimetric bomb appears to be a simple and an accurate method to predict faecal fat and avoiding expensive and cumbersome analysis.

This paper reports on a preterm infant with meconium peritonitis in which prenatal sonography demonstrated calcified peritoneal meconium associated with fetal ascites. His spontaneous and favorable outcome is described and other causes of neonatal abdominal calcifications are discussed.

During a five years period 8 newborns on 2035 admissions developed septic arthritis representing a very low incidence of 4%. Umbilical catheters were used in 3 patients. Staphylococcus aureus was the most frequent etiologic agent and in 6/8 cases blood cultures were positive for the same pathogen agent. Because of the paucity of clinical signs in the first period in the sick neonate, detection of the disorder by the radiologist assumes great importance in the neonatal intensive care unit, as early recognition and therapy may prevent residual deformity.

Serum diamine oxidase (DAO) activities were measured in 9 pregnant women and in 33 neonates during the 1st week of life. The radiometric method was used. Very high values were found in the mothers (mean +/- SE: 720 +/- 143 pmol ml-1 h-1). Neonates showed significantly elevated values (mean +/- SE: 178 +/- 54 pmol ml-1 h-1) on the 1st postnatal day when compared to the 7th day values (mean +/- SE: 27 +/- 5.7 pmol ml-1 h-1). Serial determinations showed a progressive decline from day 1 to day 7 after birth. We suggest the high serum DAO levels in neonates during the first days of life are due to leakage of placental enzyme into the circulation either at birth or during fetal life. Consequently, serum DAO cannot be used as a marker of small bowel functional integrity in the 1st postnatal week.

The preterm newborn infant for his very high growth rate is especially vulnerable to any deficiency or excess of the nutritional intake. Moreover he differs from the older infant because of the immaturity of many biological function. Such immaturity is temporary in the term newborn, while lasts longer in the preterm newborn infant. In this paper needs for energy, proteins, lipids, carbohydrates and minerals in the preterm newborn are reported. They are based on metabolic balance studies carried out in preterm newborn infants fed either human milk or different formulas. The own mother fresh milk, supplemented with phosphorus, appears to be the best feeding for the preterm infant. Formulas conveniently adapted in carbohydrates, proteins, lipids and minerals content may be used as reasonable substitutes. On the contrary the pooled pasteurized human milk is not advisable.

This study was performed in order to evaluate possible changes in behavior in jaundiced infants without perinatal complications other than hyperbilirubinemia treated with phototherapy. Thirty jaundiced infants (mean bilirubinemia 13.3 mg/100 ml, range 8.4-17.5) born spontaneously at term and undergoing phototherapy for 6 h or more, and 30 comparison subjects similar for sex, birthweight, gestational age, Apgar score, obstetrical history and father's profession were examined during the 3rd day of life according to Brazelton Neonatal Behavior Assessment Scale (BNBAS). For 6 of 26 items we found higher values for comparison group (Wilcoxon's Test): inanimate visual median (m.) 5 vs. 3 (P less than 0.05); animate visual m. 5 vs. 3.5 (P less than 0.01); visual and auditory 5.5 vs. 4 (P less than 0.005); pull-to-sit m. 6 vs. 5 (P less than 0.01); cuddliness m. 5 vs. 4 (P less than 0.01); alertness m. 5 vs. 4 (P less than 0.005). Visual orientation responses were the most compromised. On the 4th day of life, 14 infants who had terminated phototherapy at least 2 h before (mean 9.9 h) were compared with their matched comparison group subjects and the same significantly poorer performances, mainly in visual orientation, were found. At one month of age, 12 of these infants treated with phototherapy still showed a significantly poorer performance in 2 items of orientation: inanimate visual m. 6 vs. 4.5 (P less than 0.05); visual and auditory m. 6.5 vs. 4 (P less than 0.05). Whether these results depend on the jaundice or on the phototherapy remain to be established.

This study was undertaken to assess to what extent estimated energy content of 13 infant formulas was related to gross energy measured by bomb calorimetry. Measured gross energy exceeded significantly metabolizable energy as claimed by the manufacturers by applying the classical Atwater's factors by about 12% (range, 6-17%). Measured gross energy also exceeded significantly gross energy calculated by applying either FAO/WHO or our own values of heat combustion of nutrient by 6% (range, 3-9%) and 3.5% (range, 1-6%), respectively. It is concluded that for reasons of symmetry and simplicity, the labeling of the energy content of infant formulas should continue to be calculated by applying the classical Atwater's factors to the nutrient composition. However, when accurate energy balance studies are carried out, the energy content of the diet should be measured by bomb calorimetry rather than be estimated by applying conversion factors to claimed or determined nutrient composition.

The effects of the excitatory amino acids on the nucleus reticularis thalami were examined by intracellular recordings from rat thalamic slices. Non-N-methyl-D-aspartate receptor agonists and glutamate induced a membrane depolarization and a reduction in input resistance, while N-methyl-D-aspartate and aspartate induced a prolonged discharge, which in some neurons took the form of a burst firing associated with an apparent increase in membrane input resistance. Both the N-methyl-D-aspartate and the aspartate effects were blocked by D-2-amino-5-phosphonovalerate, while the effects of glutamate, kainate and quisqualate were not. The excitatory postsynaptic potential evoked by corticothalamic fiber stimulation shows two components: an early, short-lasting, 2-amino-5-phosphonovalerate-insensitive portion, and a late, 2-amino-5-phosphonovalerate-sensitive decay phase. It is suggested that glutamate acts in nucleus reticularis thalami cells preferentially on the non-N-methyl-D-aspartate receptors, while aspartate shows an N-methyl-D-aspartate-like effect. The two excitatory amino acids glutamate and aspartate play a determinant role in the modulation of thalamic activity driven by corticothalamic projection.

Jaundiced babies undergoing phototherapy often develop diarrhoea. The cause of it is still uncertain. Increasing evidence supports a role of a secretory mechanism for the diarrhoea. We therefore studied the effects of bile from congenitally jaundiced rats undergoing phototherapy and of unconjugated bilirubin on rat small intestine in vivo and in vitro. Results suggest that: (1) the bile from homozygous Gunn rats under phototherapy has an anti-absorptive effect when tested in the perfused jejunum of normal Wistar rats; (2) unconjugated bilirubin has a dose dependent secretory effect on the intestinal transport of water and electrolytes, when tested in the same system. Alteration of cyclic AMP or cyclic GMP, known intracellular mediators of secretion, was not observed. We conclude that free bilirubin is an intestinal secretagogue acting by an as yet unknown mechanism, that may mediate the secretory type of diarrhoea in jaundiced neonates undergoing phototherapy.

The etiopathogenesis and the clinical implications of fat malabsorption in preterm infants are reviewed. Low pancreatic lipase activity and impaired solubilization of lipids due to low intraluminal concentration of bile salts appear to be the main factors of the inadequate lipid absorption. The compensatory role of intragastric lipolysis could be important. Currently available informations suggest that, chylomicron formation and transport of lipids are not limiting steps, but the efficiency of these processes in neonates needs further investigations. Due to its bile-stimulated lipase activity, non-heat-treated human milk used at least in part, appears to be the most effective method to improve fat absorption in the preterm infant.

Mean birth weights and percentile charts are given for 161 singleton infants born between 24 and 30 weeks' gestation at the 2nd School of Medicine of Naples. This chart is the first for a Mediterranean population. Our data are similar to those reported from a United Kingdom population and from Japan, suggesting that ethnic differences in birth weight at this gestational age are unimportant.

We studied the behaviour of 20 preterm infants (average gestational age 33 weeks) brought to term, without any serious disorder. These infants were compared with a group of 21 healthy term infants. To evaluate behaviour we used the 26 items of the Brazelton Neonatal Behavioural Assessment Scale (BNBAS). Our preterm infants had on the whole better scores than those reported in the literature for preterm infants with various disorders. Apart from lower ability to bring hand to mouth and in getting used to visual stimuli (these differences are statistically significant) they had, in the items of orientation a lower score only in ability to follow a voice and a face (not statistically significant). These results show that preterm infants reaching term without any serious disorder do on the whole as well as full-term infants. This correlates with the observations of Dubowitz on behaviour and particularly on visual function of preterm infants and confirms the preliminary report of Daum regarding the influence of the type of neonatal pathology on the ability of orientation at the moment of term.

1. Neurones of the nucleus reticularis thalami of the rat were studied by intracellular recordings from in vitro slices. The resting membrane potential was -56.28 +/- 5.86 mV (mean value +/- S.D.); input resistance was 43.09 +/- 9.74 M omega; the time constant tau was 16.51 +/- 3.99 ms. At the resting membrane potential tonic firing is present, while at membrane potentials more negative than -60 mV a burst firing mode gradually prevails. 2. Prolonged depolarizing current pulses superimposed on a steady hyperpolarization consistently activated sequences of burst-after-hyperpolarization complexes. The all-or-none burst response consisted of Na+-mediated, TTX-sensitive fast action potentials superimposed on a low threshold spike (LTS). The burst was followed by a stereotyped after-hyperpolarization lasting 100-120 ms (BAHP), with a maxima -85 mV. The BAHP was blocked by Cd2+ and apamine but not by 8-Br cyclic AMP. The early component of BAHP was significantly attenuated by TEA. The oscillatory rhythmic discharges were abolished by agents which blocked the BAHP. 3. The presence of strong after-hyperpolarizing potentials (SAHP and BAHP) in RTN neurones plays a significant role in determining two different functional states, defined as tonic and oscillatory burst firing modes, respectively.

This paper describes two cases of gangrene in the buttock secondary to infusion of a hyperosmolar solution into the umbilical artery at birth. Because of the frequent dilatation of the umbilical arteries in asphyxiated infants, needle puncture should not be used to infuse fluids into the umbilical vein. Moreover, hypertonic solutions that can produce vascular thrombosis should be avoided in metabolic resuscitation in the delivery room.

Energy and nitrogen balances were performed in 12 very low birthweight infants fed on either human milk or on a preterm formula. Energy and nitrogen retention were significantly higher in those given the formula feed (p less than 0.05). Highly significant correlations were found between nitrogen intake and nitrogen retention and between energy retention and nitrogen retention (p less than 0.001). Multiple regression analysis failed to show any effect of energy retention on the correlation between nitrogen intake and nitrogen retention in babies fed on human milk. Protein deficiency seems to be the most likely explanation of poor growth in infants fed on human milk.

The perinatal histories of 27 newborn infants with NEC were compared to those of 54 infants of equivalent birth weight who did not have NEC during an 8-year study period to see if possible predisposing factors were independent of the confounding effect of birth weight. No differences were observed in gestational age, degree of intrauterine growth retardation, premature rupture of membranes, perinatal asphyxia, skin temperature at admission, haematocrit, presence or absence of respiratory distress syndrome, umbilical catheter placement, start and type of feeding or presence of positive blood cultures. Prematurity is the greatest risk factor predisposing to the development of NEC and the perinatal problems which precede the onset of NEC are common among all premature infants.

This study was performed to determine whether covering the eyes with an opaque screen over the head end of the bassinet instead of the normal patch would improve the behavioral organization of jaundiced, but otherwise healthy, term infants treated with phototherapy. 38 matched infants were randomly assigned to have a patch or a screen. Serum bilirubin at the time of observation was 11.2-17.5 mg/100 ml (mean = 13.7, patch) and 9.4-16.4 mg/100 ml (mean = 13.4, screen). 19 infants, of whom 11 were jaundiced (6.2-14.3 mg/100 ml, mean = 10.3), served as control subjects. The infants were examined with the Brazelton scale on the 3rd day after birth, when the patch subjects had been under blue light from 6 to 45 h (mean = 23.9), and the screen subjects from 6 to 61.5 h (mean = 22.6). The control subjects scored better (all differences, p less than 0.05) than the patch subjects on inanimate visual, animate visual, visual and auditory, alertness. The control subjects also did better than the screen subjects on inanimate visual, animate visual, animate auditory, visual and auditory, alertness, but poorer on motor maturity and consolability. The screen subjects did poorer than the patch subjects only on skin color lability. At 1 month of age, 9 sets of matched infants were examined. The only difference was that the control subjects did better than the patch subjects on animate visual and lability of state. Our data confirm the poorer short-term orientation performance of jaundiced infants treated with phototherapy but do not indicate that covering the eyes with an opaque screen improves behavioral organization.

Thirty jaundiced neonates with diarrhoea who were being treated with phototherapy and 30 matched control infants were studied to try and find out the cause of the diarrhoea. Faecal osmolality and electrolyte concentrations were measured, which gave clear evidence that the diarrhoea arose from intestinal secretion. Rectal water and electrolyte absorption in 10 jaundiced infants receiving phototherapy, in 10 jaundiced infants not receiving phototherapy, and in 10 healthy controls was measured with a rectal dialysis bag. A further group of eight jaundiced infants was also studied both during and after phototherapy to document the reversal of ion transport changes. Absorption of water, sodium chloride, and potassium was significantly impaired in the patients receiving phototherapy compared with each of the control groups. Such impairment was transient, as it was not apparent when the jaundice faded and phototherapy was stopped. These data show that the colon plays a part in the pathogenesis of secretory diarrhoea and that both hyperbilirubinaemia and phototherapy are necessary for such an effect to develop.

The prolonged and total separation of a premature infant from its parents in a Neonatal Intensive Care Unit is an additional element of anxiety in a family already upset by the premature birth itself. However, while encouraging parents to participate in the care of their child lessens some problems, it also tends to create others. The environment of intensive care and continuous contact with the nursing of the infant may give rise to distress, and parental reactions may interfere with the running of the department. We report some results from 60 semistructured interviews between a clinical psychologist and 30 couples whose preterm infants had spent at least 10 days in the Neonatal Intensive Care Unit (NICU) of the 2nd School of Medicine of Naples. For more than 4 years we have encouraged parents to take care of their infants, to touch them, change them and feed them. The results of our study appear to suggest that allowing parents unrestricted access to the Unit stimulates paternal interest in the child.

This study is aimed at the investigation of the morphological and electrophysiological characteristics of neurons from the nucleus reticularis thalami in rat thalamic slices incubated in vitro. Ten neurons were recorded in the ventrobasal complex, four of which were successfully injected following horseradish peroxidase injection. Two main types of reticular thalamic neurons were morphologically identified: (1) the small fusiform 'f' cells characterized by a very elongated perikaryon, dendritic arborization prevalent in the rostrocaudal and dorsoventral planes, and an axon without any collaterals branching within the nucleus reticularis thalami; and (2) the large fusiform 'F' neurons with dendrites arborizing mainly in the horizontal plane and with axonal branches within the nucleus reticularis thalami. The electrophysiological properties of the neurons were similar in F and f cells. The reticular neurons showed, in resting conditions, a single spike response followed by a postexcitatory hyperpolarizing potential. The hyperpolarization of these neurons transformed the single spike response into a burst discharge similar to that observed in thalamic relay neurons at resting membrane potential. The same phenomenon was observed when bicuculline was administered by perfusion to the slices and, in this case, a recovery to a single spike response was obtained by a depolarizing d.c. current injection. By contrast, the local administration of GABA induced a depolarization with a pronounced decrease in input resistance. The present data demonstrate the presence of at least two neuronal subtypes within the nucleus reticularis thalami, suggesting that only one is responsible for the phenomenon of auto-inhibition by means of intrinsic axon collaterals. Moreover, it is hypothesized that intranuclear GABAergic collaterals could control neuronal excitability of reticular thalamic cells by both shunting the membrane and shifting the burst firing to a single spike firing mode.

Significant production of breath hydrogen has been shown in premature infants, suggesting limited intestinal capacity for digestion of carbohydrate. To evaluate net absorption of carbohydrate 24 three day balance studies were carried out in seven preterm infants fed pasteurised banked human milk and in 17 preterm infants fed a formula containing 75% lactose and 25% glucose polymers. Because carbohydrate reaching the colon may be converted to organic acids by bacterial flora, carbohydrate net absorption was determined by quantitating the faecal excretion of energy derived from carbohydrate. The carbohydrate derived energy content of milk and stools was calculated as the difference between the measured gross energy and the sum of energy related to nitrogen and fat. Faecal loss of carbohydrate derived energy was lower in the group fed formula (1.9 (SD 1.2) kcal/kg/day) than in the group fed human milk (4.0 (SD 1.8) kcal/kg/day). Net absorption of carbohydrate derived energy was 97.0 (SD 1.9)% as opposed to 92.6 (SD 3.9)%, respectively. Within each group there was no significant relation between carbohydrate energy absorption and fat, nitrogen, or gross energy absorption. Thus, although less complete with human milk than with formula, apparent absorption of energy derived from carbohydrate seemed quite satisfactory in these preterm infants.