[Refeeding syndrome]. / Syndrome de renutrition inappropriée.

Refeeding syndrome (RS) is a rare but severe condition that is poorly understood, often under-diagnosed and can lead to death. It occurs within 5 days after refeeding in patients after prolonged fasting or in a context of undernutrition. As a consequence of the abrupt transition from catabolism to anabolism, RS is defined as a decrease in plasma levels of phosphorus, potassium and/or magnesium, whether or not associated with organ dysfunction resulting from a decrease in one of the electrolytes or a thiamine deficiency, after refeeding. The clinical symptoms are varied and non-specific and are related to hydro electrolyte disorders, sodium-hydroxide retention or failure of one or more organs. Patient management should be appropriate with regular clinical examination and careful biological monitoring, including hydro electrolyte monitoring. The correction of hydroelectrolytic disorders and systematic thiamine supplementation are essential during refeeding, that must be done carefully and very progressively, whatever its form (oral, enteral or parenteral). The severity of the refeeding syndrome indicates that its prevention and screening are the corners of its management in at-risk patients.

Sensory-specific satiety for a food is unaffected by the ad libitum intake of other foods during a meal. Is SSS subject to dishabituation?

Sensory-specific satiety (SSS) is defined as a decrease in the pleasantness of a specific food that has just been eaten to satiation, while other non-eaten foods remain pleasant. The objectives of this study were the following: (1) to investigate whether SSS for a food is affected by the ad libitum intake of other foods presented sequentially during a meal, (2) to compare the development of SSS when foods are presented simultaneously or sequentially during a meal, and (3) to examine whether SSS is modified when foods are presented in an unusual order within a meal. Twelve participants participated in three tasting sessions. In session A, SSS for protein-, fat- and carbohydrate-rich sandwiches was measured after the ad libitum consumption of single type of each of these foods. In session B, SSS was measured for the same three foods consumed ad libitum but presented simultaneously. Session C was identical to session A, except that the presentation order of the three foods was reversed. The results indicate that once SSS for a given food is reached, the ad libitum consumption of other foods with different sensory characteristics does not decrease SSS, regardless of the order in which the foods are presented. Once reached, SSS is thus not subject to dishabituation during a meal.

Variety enhances food intake in humans: role of sensory-specific satiety.

Twenty-one subjects were studied to evaluate the effect of renewal of sensory stimulations of previously eaten foods on sensory-specific satiety and intake. The subjects ate French fries then brownie cakes ad libitum in three situations: "monotonous" - fries then brownies were consumed alone; "simultaneous" - condiments (ketchup and mayonnaise for the fries, vanilla cream and whipped cream for the brownies) were added during intakes; "successive" - after intake of fries alone, ketchup then mayonnaise were available with fries and, after intake of brownies alone, vanilla cream then whipped cream were offered with brownies. The quantities eaten in the "simultaneous" and "successive" situations were higher (p<0.001) than those in the "monotonous" one (1485+/-582 and 1682+/-777 kcal vs 1195+/-552 kcal, respectively). In the "successive" situation, hedonic ratings for fries diminished during intake but increased after the introduction of ketchup, leading to additional intake of fries. Similarly, hedonic ratings for brownies diminished during intake and increased after the introduction of vanilla cream leading to additional brownie intake (mayonnaise and whipped cream had no significant effect). Food variety, obtained by adding condiments can increase food intake in the short term. The mechanism by which food consumption is increased after the addition of condiments is introduced is at least partly related to the attenuation of sensory-satiety for a given food.

Alliesthesia in visual and auditory sensations from environmental signals.

'Alliesthesia' describes the fact that sensory stimuli can arouse pleasant or unpleasant sensations according to the internal state of a person. In the present work, the hedonicity aroused by stimuli from the environment in visual and auditory sensations was evaluated in 5 situations: 1) daytime without sensory stimulations (no video-tape); 2) daytime with poor sensory stimulations (uninteresting video-tape film); 3) daytime with rich sensory stimulations (interesting chosen movie on video-tape); 4) night-time without sensory stimulations (no video-tape); 5) night-time with poor sensory stimulations (uninteresting video-tape). During the day, hedonic ratings decreased with time in the no- and uninteresting video-tape film conditions (p<0.01), but increased with the chosen movie (p<0.05). During the night, hedonic ratings decreased similarly to daytime ratings with the uninteresting video-tape film (p<0.01) but rose in the no-video-tape environment (p<0.01). The time course of motivation to leave the environment mirrored that of hedonic ratings. Changes in hedonic ratings as well as motivation to leave the environment correlated with the state of tiredness in the day-no-video and night-no-video situations (r=0.541 and r=-0.593; p<0.01). Thus, alliesthesia occurred in visual and auditory sensations that originated from the environment, and motivated behavior that was not consummatory. Such results suggest that alliesthesia is a general property of all sensations, and emphasizes the fundamental role of pleasure in motivation for all behaviors.

Sensory-specific satiety with simple foods in humans: no influence of BMI?

OBJECTIVE: Olfacto-gustatory sensory-specific satiety plays an important role in the termination of food ingestion. A defect in this mechanism, by increasing food intake, could be a factor in development of overweight. The present study was conducted to explore whether sensory-specific satiety in the overweight may be different from that in normal-weight subjects. SUBJECTS: 144 subjects (half men, half women; age range: 17-62 years; BMI range: 17-39 kg m(-2)). MEASUREMENTS: Olfactory pleasure (OP) and flavor pleasure (FP) were evaluated before and after ingestion of a single chosen food. Six foods from three classes were offered: cucumber and tomato, pineapple and banana, and peanut and pistachio. According to the subjects' preference for one of them, subjects were classified into six groups (24 subjects each with equal sex ratio). The experimental sequence was (1) evaluation of the six foods (OP), (2) ad libitum intake of the preferred food (FP) and (3) second evaluation of the six foods (OP). RESULTS: Food intake was limited by sensory-specific satiety (that is, a decline in FP for the ingested food) in overweight subjects just as it was in the leanest. There was no significant correlation between BMI and hedonic parameters (OP and FP) or intakes (quantity and volume). Pre-ingestive OP and FP correlated with the ingested food's weight (OP: r=0.468; FP: r=0.415; P<0.01), volume (OP: r=0.428; FP: r=0.407; P<0.01) and intake duration (OP: r=0.184; FP: r=0.343; P<0.05). The decline in OP, but not in FP, correlated with ingested weight (r=0.271, P<0.01) and volume (r=0.263, P<0.01) but not with duration. CONCLUSION: After intake of a single food, olfacto-gustatory sensory-specific satiety correlated with the ingested food's weight and volume and with the duration of ingestion, but not with bodyweight. This suggests that overweight and lean subjects have similar hedonic control of food intake with simple foods.

Effects of two types of fatigue on the VO(2) slow component.

The aim of the study was to test the hypothesis of the involvement of type II fibres in the V.O (2) slow component phenomenon by using two prior fatiguing protocols on the knee extensor muscles. Nine subjects performed three constant-load cycling exercises at a work rate corresponding to 80 % of their V.O (2) max: (i) preceded by a 20-min fatiguing protocol using electromyostimulation (EMS), (ii) preceded by a 20-min fatiguing protocol using voluntary contractions (VOL), and (iii) without fatiguing protocol (NFP). Voluntary and evoked neuromuscular properties of the knee extensor muscles were tested before (PRE) and after (POST) the two fatiguing protocols. Results show a significant reduction in voluntary force after both fatiguing protocols (-19.9 % and -11.8 %, in EMS and VOL, respectively p<0.01). After EMS, this decrease was greater than after VOL (p<0.05) and was combined with a slackening of muscle contractile properties which was absent after VOL (p<0.05). Regarding the effects on oxygen uptake kinetics, the appearance of the slow component was delayed after EMS and its amplitude was lower than those obtained in VOL and NFP conditions (0.48+/-0.07 vs. 0.75+/-0.09 and 0.69+/-0.08 L . min (-1), respectively; p<0.05). It can thus be concluded that exercises dedicated to preferentially fatiguing type II fibres may alter V.O (2) kinetics.

Postprandial thermogenesis and alimentary sensory stimulation in human subjects.

OBJECTIVE: To study the role of alimentary sensory stimulation on the thermic effect of food. SUBJECTS: Nine male healthy volunteers (age: 20-34y, body mass index (BMI): 17.4-25.3kg/m2). DESIGN AND MEASUREMENTS: Four experimental situations were investigated on different days. Subjects: 1) ate a four course meal containing 2582kJ (meal), 2) saw, smelt and tasted the same courses (alimentary sensory stimulation), 3) saw, smelt and tasted non-alimentary substances (non-alimentary sensory stimulation), 4) received directly into the stomach the previous meal (tube feeding). Energy expenditure (EE) was measured over a 20 min rest period, then for 110 min. RESULTS: The changes over midday rest EE were: meal = +12.0%; alimentary sensory stimulation = +3.2%; non-alimentary sensory stimulation= -2.6%; tube feeding = +5.7%. The increase in EE was higher after the meal than after either alimentary sensory stimulation (P < 0.01) or tube feeding (P < 0.01); the increases after the last two were, in turn, greater than after non-alimentary sensory stimulation (P < 0.05). Only after alimentary sensory stimulation, was the increment in EE significantly correlated with BMI (r= -0.700; P < 0.05). CONCLUSIONS: The early phase of postprandial thermogenesis therefore depends on both sensory and metabolic events. Furthermore, the sensory component was more pronounced in the lean subjects.

Central sleep apnoea in Arnold-Chiari malformation: evidence of pathophysiological heterogeneity.

We report on the case of two young patients with type I Arnold-Chiari malformation (ACM), as revealed by a central sleep apnoea (CSA) syndrome without any other neurological defect. Case 1 was a 14-yr-old male patient, who developed severe alveolar hypoventilation and needed long-term mechanical ventilation via a tracheostomy. Case 2 was a 39-yr-old male patient, who developed features suggestive of sleep apnoea and responded to nasal continuous positive airway pressure ventilation despite the central type of apnoeas. These two cases illustrate the different pathophysiological mechanisms involved in CSA, namely a blunted chemical drive (in hypercapnic patients) and an increased chemical drive, which destabilizes the breathing pattern during sleep (in normo/hypocapnic patients). Central sleep apnoea can be the initial manifestation of Arnold-Chiari malformation and can lead to a life-threatening condition.

Satiety power of dietary fat: a new appraisal.

Accumulating evidence suggest that a good way to compare the satiety power of meals with different compositions or energy contents is to measure the onset latency of the next meal when freely requested by subjects deprived of any time cues. This study was performed in normal-weight young men (aged 19-24 y) isolated from time cues. At sessions 1 and 2, we studied the effects of two high-carbohydrate pasta lunchs with either 50 g low-energy butter substitute (lunch A) or 50 g butter (lunch B) on hunger ratings, on the latency of the dinner request, and on energy and nutrient intakes at the offered ad libitum dinner. Sessions 3 and 4 were designed to examine the effects of the two lunchs on the postlunch and predinner profiles of plasma glucose, insulin, glucagon, and lipids; consequences on the metabolic and hormonal responses to the fixed dinner offered on request also were tested. The addition of 1588 kJ butter to the pasta lunch compared with the addition of 67 kJ butter substitute had no effect on hunger ratings but significantly delayed the onset of dinner by approximately 38 min; however, neither energy intake nor nutrient intakes were different. The high-fat lunch led to a slightly different postlunch plasma glucose concentration profile but, as expected, to higher plasma triacylglycerol and fatty acid concentrations. The high-fat lunch also led to postdinner glucose intolerance with normal insulin and high fatty acid concentrations that may help explain the partial and delayed adjustment in energy intake after a high-fat meal as reported by some studies.

[Evaluation of the ventilatory function in elderly subjects]. / Evaluation de la fonction ventilatoire chez le sujet âgé.

OBJECTIVES: Many elderly subjects are at risk of respiratory failure due to effect of age on ventilatory system and the deleterious effects of toxins and respiratory diseases. As spirometry is the main technique currently used to detect altered ventilatory function we first used this method in very elderly subjects then compared the results with clinical measurements of chest and abdominal ampliation. METHODS: Among 65 subjects over 75 years of age, with no cardiorespiratory or neuropsychologic impairment and who had undergone spirometry and chest and abdominal ampliation measurements in 1991, 24 were re-examined in 1994 using exactly the same techniques. Forced vital capacity and maximum expiratory volume/second were measured at the patient's home with a previously calibrated spirometer. All tests were run according to the recommendations of the European Respiratory Society. Variations in upper chest, lower chest and abdominal circumferences were also recorded. RESULTS: Mean age of the subjects was 84.1 +/- 3.7 years and all spirometric tests were reproductible within a given measurement session. There was no significant difference for forced vital capacity or for maximum expiratory volume/second between the 1991 and the 1994 values with variations of 2.1 +/- 0.4 and 9.4 +/- 3.4% respectively. Four of the 24 initially asymptomatic subjects had signs of obstruction which resolved in 2 with the salbutamol and/or ipratropium bromide. The correlations between spirometric data and chest and abdominal ampliations were significative. CONCLUSIONS: Spirometry can be an effective tool in elderly patients. In addition to frequent discovery of reversible bronchial obstruction (7 to 41% according to the series), it can be used to screen for reduced ventilatory "reserve". Chest ampliations measures also appear to be simple means of determining which subjects could benefit from physical therapy aimed at improving chest and abdominal musculature.

The energetic cost of some daily activities: a comparison in a young and old population.

We compared the energetic costs of some daily activities in two groups, 10 young people (24.3 +/- 2.8 years) and 10 old people (74.4 +/- 2.2 years): rising and sitting back down on a seat, getting up from and lying down on a bed and getting up from the floor. We measured the oxygen consumption and the time necessary for the activities. The results showed a noteworthy economical energetic procedure when rising and sitting back down on a seat among the older group. The values of the energy expenditure were respectively 3.9 +/- 1.3 cal/kg in the older group and 5.8 +/- 1.6 in the younger one with a standard seat (45 cm) and 2.7 +/- 1.2 vs 5.2 +/- 1.5 with a raised seat (60 cm). The activities did not vary significantly in time in the two age groups. This procedure could be understood as an adaptation of the energy expenditure to the reduced aerobic capacity with ageing. Conversely, getting up from and lying down on the floor or a standard hospital bed involved the same energy expenditure in the older and younger group, but performing these activities took significantly longer for the older people (+60% for getting up from the floor, +33% from the bed). As these activities revealed no economical energetic procedure in the older group, they appeared responsible for a strong factor of dependence. The importance of a learning process particularly for the most usual movements in everyday life is discussed.

Lung function in advanced age: study of ambulatory subjects aged over 75 years.

Spirometric parameters including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and various parietal parameters (superior and inferior rib cage and abdominal maximal expansion amplitudes) were measured in 65 ambulatory subjects aged over 75 years. The population was divided into three age groups: group 1: 75-79; group 2; 80-84, group 3: 85 and older. A marked decrease in clinical and spirometric results was observed between groups 1 and 2, and 1 and 3, but there was no difference between groups 2 and 3. Such findings might be attributed to a survival effect. There was a high correlation between the parietal parameters and FVC and FEV1. In clinical practice, this simple parietal assessment may be of value in the identification of elderly subjects at risk of acute respiratory distress.

Hyperventilation does not increase alveolar surfactant phospholipids in the anesthetized rat.

Pulmonary distension elicits an increase of the surfactant secretion. Effects of hyperventilation on this same secretion are less precise since they were observed under particular experimental conditions. We report a study of the effects of hyperventilation on the phospholipid content of alveolar lining fluid in the rat. One hour's hyperventilation induced by addition of a dead space to the tracheal cannula of anesthetized rats did not affect the phospholipid content of broncho-alveolar lavage fluid collected in situ immediately after killing. Phospholipid content (4.82 +/- 1.39 mg.g-1 dry lung weight) did not differ significantly from that in anesthetized spontaneously breathing rats (4.00 +/- 1.09 mg.g-1 dry lung weight). Furthermore, phospholipid content was not found to increase in animals maintained at 37 degrees C for 20 min (4.43 +/- 1.30 mg.g-1 dry lung weight) or 60 min (3.55 +/- 0.88 mg.g-1 dry lung weight) after killing. In conclusion the constancy of phospholipid content can be due either to a normal secretion or to a hypersecretion with a concomitant removal.

Effect of quinacrine on lipid content of bronchoalveolar lavage fluid in guinea pigs sensitized to ovalbumin.

In both ovalbumin-sensitized and ovalbumin-challenged guinea pigs, the phospholipid content of bronchoalveolar lavage fluid is decreased with respect to that of controls. In the sensitized guinea pig, the activity of lung membrane phospholipase is increased and the phospholipid content of lung membranes is decreased. In determining whether alveolar phospholipids are metabolized in a similar way, quinacrine, a phospholipase A2 inhibitor, was administered (10 mg/kg intravenously) to control, sensitized, and challenged animals before inhalation of ovalbumin. Pulmonary ventilation and lung mechanics were measured both before and after the injection of quinacrine and inhalation of ovalbumin. Phospholipid content was measured in the bronchoalveolar lavage fluid. In the control and sensitized groups quinacrine had no effect on pulmonary ventilation and lung mechanics, and in the challenged group it reduced the intensity of anaphylactic bronchospasm. In control animals it did not change the phospholipid content, whereas in the sensitized and challenged animals it suppressed the decrease of phospholipid content. The results suggest that in the sensitized and challenged guinea pigs alveolar phospholipids are degraded by phospholipase A2, the activity of which is increased.

Reduction of negative alliesthesia for sweet gustatory stimuli by cyproheptadine, a serotonin antagonist.

Cyproheptadine (CH) is a serotonin antagonist that increases food intake and body weight. In order to elucidate its mechanism of action on the control of food intake, hunger ratings, pleasure-displeasure to sweet gustatory stimuli and negative alliesthesia induced by a 50 g glucose load were compared in 14 healthy subjects after they had received a placebo or 16 mg of CH. Cyproheptadine did not affect the hunger rating, nor the affective rating in fasted subjects, but it reduced significantly the negative alimentary alliesthesia induced by the glucose load. It was concluded that CH increases food intake more by reducing satiation than by increasing hunger. This is in line with the anti-serotoninergic properties of CH, and the action of serotonin on the control of food intake.

Alveolar phospholipids, hyperventilation and temperature of conservation of rat lungs.

Hyperventilation has been found to increase the phospholipid content of broncho-alveolar lavage fluids. Had the temperature of conservation of the lungs an influence? Two groups of rats were allowed to ventilate normally (NV), and two groups (HV) were induced to hyperventilate for 1 h by addition of a dead space. After sacrifice, the isolated lungs were kept for 25 min at 37 degrees C (NV37 and HV37), or 10 degrees C (NV10 and HV10), and then washed at the same temperatures. The phospholipid content of lavage fluid was only found to be increased in the HV37 group (P less than 0.05). Neither hyperventilation followed by conservation of lungs at 10 degrees C nor normal ventilation followed by conservation of lungs at 37 degrees C led to an increase in phospholipid content. It was the association of hyperventilation and conservation of lungs at 37 degrees C that led to the increase. In vivo hyperventilation is thought to lead to an equal increase in secretion and reabsorption of alveolar phospholipids, and conservation of the lungs at 37 degrees C was thought to lead to an imbalance between these two processes.

Role of palatability on meal-induced thermogenesis in human subjects.

To study the possible participation of food-induced sensory stimulation on meal thermogenesis an experiment was performed with eight female subjects. On alternate days subjects were fed either a highly palatable meal (HPM), containing 710 calories, or a nonpalatable meal (NPM). The NPM was prepared by mixing all the ingredients of the HPM and was presented to the subjects as a desiccated biscuit. The subjects were not informed about the composition of the NPM, which they rated as tasteless and unappetizing. The increase in O2 consumption was approximately 20% during the 90 min following the HPM compared with 12% with the NPM (P less than 0.01). With comparable increases in plasma glucose, plasma insulin level was significantly (P less than 0.01) lower following NPM ingestion than with ingestion of the HPM. At that time a significant increase in plasma norepinephrine was also observed but only following ingestion of the HPM. It would appear that both central sensory stimulation or plasma insulin level, as affected by food palatability, could be considered at this time as possible activators of the increased sympathetic activity observed following ingestion of the HPM. It is suggested that a part of meal thermogenesis is due to food palatability and that the concomitant activation of the sympathetic system may be related to this action.

Palatability and postprandial thermogenesis in dogs.

The role of palatability on postprandial thermogenesis was determined in six mongrel dogs of approximately 16 kg. Oxygen uptake (VO2) was continuously monitored by indirect calorimetry for 1 h before and 2 h after a standard meal of 1,390 kcal. In the first experiment each dog was given access to the meal, which was ingested within 5 min. In a second experiment the same meal was sham fed and collected into an esophageal pouch. In a third experiment the dogs were tube fed. In the first experiment a biphasic response was found in the postprandial increase in metabolic rate; a first phase lasting approximately 40 min and the other from 40 to 125 min. In the second experiment the increase in VO2 was comparable with that of the first experiment for the first 40 min but almost abolished for the remaining period; the sight and smell of food alone produced a similar effect. In the third experiment tube feeding caused a small increase in VO2, which was four times smaller than that found in both the first and the second experiment during the initial phase. However, during the second phase the increase in VO2 was comparable with that of experiment 1. An initial phase of feeding lasting approximately 40 min is identified with food palatability, whereas the second phase would correspond to a large extent to specific dynamic action of food.