Leftward oculomotor prismatic training induces a rightward bias in normal subjects.

Wedge prisms shifting the visual field laterally create a mismatch between the straight ahead position signalled by vision and that encoded by extraretinal and head-on-trunk proprioceptive information. Short-term adaptation to left-deviating prisms in normal subjects results in a visuomotor attentional bias towards the right-hand side (aftereffect). Prismatic adaptation (PA) is usually induced through a training consisting in repeated ballistic movements of the dominant arm towards visual targets, while participants are wearing prismatic goggles. The present study demonstrates that an original oculomotor PA procedure with leftward deviating prisms-without pointing movements and only consisting in repeated gaze shifts towards visual targets-can induce a rightward bias in normal subjects as assessed by visual straight ahead and line bisection tasks (Experiments 1 and 2). We show that oculomotor PA induces a bias in line bisection similar to that reported after visuomotor PA (Experiment 2). We suggest that a conflict between retinal, extraretinal and proprioceptive information about the straight ahead location causes the observed effects. In follow-up experiments 3, 4, and 5, we demonstrate that neither eye deviation without prisms nor shift of the visual field without eye deviation induces PA biases. We propose that an optimal integration model of visual and proprioceptive inputs can best account for the observed results.

The role of the right parietal lobe in anorexia nervosa.

BACKGROUND: Patients with anorexia nervosa (AN) overestimate their size despite being severely underweight. Whether this misperception echoes an underlying emotional disturbance or also reflects a genuine body-representation deficit is debatable. Current measures inquire directly about subjective perception of body image, thus distinguishing poorly between top-down effects of emotions/attitudes towards the body and disturbances due to proprioceptive disorders/distorted body schema. Disorders of body representation also emerge following damage to the right parietal lobe. The possibility that parietal dysfunction might contribute to AN is suspected, based on the demonstrated association of spatial impairments, comparable to those found after parietal lesion, with this syndrome. METHOD: We used a behavioral task to compare body knowledge in severe anorexics (n=8), healthy volunteers (n=11) and stroke patients with focal damage to the left/right parietal lobe (n=4). We applied a psychophysical procedure based on the perception, in the dark, of an approaching visual stimulus that was turned off before reaching the observer. Participants had to predict whether the stimulus would have hit/missed their body, had it continued its linear motion. RESULTS: Healthy volunteers and left parietal patients estimated body boundaries very close to the real ones. Conversely, anorexics and right parietal patients underestimated eccentricity of their left body boundary. CONCLUSIONS: These findings are in line with the role the parietal cortex plays in developing and maintaining body representation, and support the possibility for a neuropsychological component in the pathogenesis of anorexia, offering alternative approaches to treatment of the disorder.

The updating of the representation of visual space in parietal cortex by intended eye movements.

Every eye movement produces a shift in the visual image on the retina. The receptive field, or retinal response area, of an individual visual neuron moves with the eyes so that after an eye movement it covers a new portion of visual space. For some parietal neurons, the location of the receptive field is shown to shift transiently before an eye movement. In addition, nearly all parietal neurons respond when an eye movement brings the site of a previously flashed stimulus into the receptive field. Parietal cortex both anticipates the retinal consequences of eye movements and updates the retinal coordinates of remembered stimuli to generate a continuously accurate representation of visual space.

The mental representation of hand movements after parietal cortex damage.

Recent neuroimagery findings showed that the patterns of cerebral activation during the mental rehearsal of a motor act are similar to those produced by its actual execution. This concurs with the notion that part of the distributed neural activity taking place during movement involves internal simulations, but it is not yet clear what specific contribution the different brain areas involved bring to this process. Here, patients with lesions restricted to the parietal cortex were found to be impaired selectively at predicting, through mental imagery, the time necessary to perform differentiated finger movements and visually guided pointing gestures, in comparison to normal individuals and to a patient with damage to the primary motor area. These results suggest that the parietal cortex is important for the ability to generate mental movement representations.

Schema cells in the macaque hippocampus.

Concept cells in the human hippocampus encode the meaning conveyed by stimuli over their perceptual aspects. Here we investigate whether analogous cells in the macaque can form conceptual schemas of spatial environments. Each day, monkeys were presented with a familiar and a novel virtual maze, sharing a common schema but differing by surface features (landmarks). In both environments, animals searched for a hidden reward goal only defined in relation to landmarks. With learning, many neurons developed a firing map integrating goal-centered and task-related information of the novel maze that matched that for the familiar maze. Thus, these hippocampal cells abstract the spatial concepts from the superficial details of the environment and encode space into a schema-like representation.

Protection of oligodeoxynucleotides against nuclease degradation through association with self-assembling peptides.

Aggregates of the self-assembling peptide EAK16II or EAK16IV and oligodeoxynucleotides (ODNs) were prepared, and their stability upon diluting the solution was investigated by UV-vis spectroscopy. The aggregates prepared at pH 4 and pH 7 did not dissociate after the solution was diluted 5- and 10-fold. The resistance against Escherichia coli exonuclease I of the ODN located in the EAK-ODN aggregates was studied by fluorescence resonance energy transfer (FRET) after the ODN had aggregated with EAK16II or EAK16IV at pH 4 or pH 7. The effect that the peptide sequence, peptide concentration, pH, and centrifugation had on protecting the aggregated ODN against nuclease degradation was investigated. Significant nuclease resistance was obtained after the EAK-ODN aggregates had been prepared at pH 4, with an EAK16IV concentration greater than a threshold value, and ensuring that the solution was not centrifuged immediately after sample preparation. Centrifuging the EAK16IV-ODN solution immediately after sample preparation resulted in the loss of this nuclease protection. However, if the solution of EAK-ODN aggregates was centrifuged 24 h after sample preparation, the nuclease protection afforded by the EAK16IV-ODN aggregates to the ODN was maintained even after being subject to a 10-fold dilution and up to 4 rounds of centrifugation over 4 days.

Antipyretic efficacy and safety of a single intravenous administration of 15 mg/kg paracetamol versus 30 mg/kg propacetamol in children with acute fever due to infection.

OBJECTIVES: An intravenous formulation of paracetamol and an intravenous formulation of propacetamol (prodrug of paracetamol) were compared in children with acute fever due to infection in order to determine the antipyretic efficacy and safety during the 6-hour period after administration. METHODS: A total of 67 patients aged 1 month to 12 years and with a rectal body temperature between 38.5 degrees C and 41 degrees C, were randomized to receive either intravenous paracetamol 15 mg/kg (n = 35) or propacetamol 30 mg/kg (n = 32) under double-blind conditions. RESULTS: The non-inferiority of intravenous paracetamol compared to propacetamol was demonstrated (non-inferiority margin = 0.5 degrees C) by the median body temperature reduction of 1.9 degrees C in the intravenous paracetamol group and the reduction of 2.05 degrees C in the propacetamol group. The difference in the incidence of local adverse events was statistically significant (p = 0.0134) with more local adverse events in the propacetamol group (9, 28.1%) than in the intravenous paracetamol group (2, 5.7%). CONCLUSION: This double-blind, randomized, clinical trial demonstrates the non-inferiority of a single administration of 15 mg/kg intravenous paracetamol in comparison to 30 mg/kg propacetamol in terms of body temperature reduction in children aged 1 month to 12 years with acute fever due to infection. It confirms the better local safety of intravenous paracetamol in comparison to propacetamol.

[Pseudomonas aeruginosa and cystic fibrosis: first colonization to chronic infection]. / Pseudomonas aeruginosa et mucoviscidose: "de la primocolonisation a l'infection chronique".

Pseudomonas aeruginosa (Pa) is the most common virulent respiratory pathogen in cystic fibrosis and is characterized by an important capacity of adaptation, adherence and communication. The factors of virulence of Pa play a major part in adherence with the respiratory epithelial cells and in occurrence of infectious episodes. The factors responsible for the transition of first Pa acquisition to the chronic infection are not elucidated yet. The system of secretion of type III and the quorum sensing (QS) play an important role. The QS would intervene in the maturation of the biofilm of Pa, responsible for the "mucoid" phenotype of Pa, associated to a degradation of the respiratory function. We made a retrospective study on the period 1984-2005 within the Center of Cystic fibrosis of Caen allow to determine the percentage of firstly-colonized and chronic infected patients with Pa according to age. At 6 months of life, 11% of the infants were colonized with Pa reaching 48% to 7 years and 85% at the 18 years age. The percentage of chronic children carrying Pa was 0% at 1 year, 11% at 4 years, 44% at 12 years and 74% at 18 years according to the method of Kaplan-Meier. Comparing the period 1984-1994 with that of 1995-2005, the firstly-colonization and the chronic carrying of Pa occurred earlier and significantly during the second period. The current objective, beside the respiratory care, comprises the maintenance of an optimal nutritional statute and, waiting for an effective vaccine, the development of new therapeutic targets in order to attenuate the virulence of the stocks of Pa and as much as possible to delay the age of firstly-colonization and the age of chronic colonization with mucoid Pa.

The triangular test to assess the efficacy of metoclopramide in gastroesophageal reflux.

BACKGROUND: Sequential methods are particularly interesting when recruitment is difficult because they may allow a study to be stopped early while maintaining type I and II error rates. METHODS: This placebo-controlled, randomized double-blind study was aimed at assessing the efficacy of metoclopramide (0.2 mg/kg three times daily during 14 days) on gastroesophageal reflux in infancy. The main end point was the relative variation of the percentage of time at pH < 4 between inclusion (day 0) and evaluation (day 14) assessed on two 24-hour esophageal pH recordings. Statistical analysis was performed with use of a sequential method, the triangular test. RESULTS: The study was stopped after the seventh analysis (39 infants evaluated: 20 placebo and 19 metoclopramide) without showing the expected benefit. Improvement on the main end point was 30% +/- 48% (mean +/- SD). Corresponding unbiased median estimates were 22% for placebo and 39% for metoclopramide (p = 0.28, sequential analysis). On day 14, the percentage of time at pH < 4 was 8.1% +/- 11.7% for placebo and 6.7% +/- 9.2% for metoclopramide (p = 0.68, t test), and the number of reflux episodes > 5 minutes was 3.0 +/- 3.5 for placebo and 1.9 +/- 3.0 for metoclopramide (p = 0.33, t test). CONCLUSION: If a tendency for a superior improvement with metoclopramide than with placebo was observed on the main end point, it was lower than expected and the difference was not significant. Compared with the corresponding single-stage design, the triangular test allowed to stop the study with a 15% reduction in sample size.

Molybdenum content of term and preterm human milk during the first 2 months of lactation.

To assess the molybdenum supply and requirements of preterm infants, Mo concentration was determined in milk from mothers of 6 term and 11 preterm newborns; no difference was found between fore- and hindmilk and no diurnal variations were found during 24-h collections. Respective values (means +/- SD) of term and preterm milks were 10.2 +/- 3.7 and 4.0 +/- 3.7 micrograms/L (106.2 +/- 38.5 and 41.7 +/- 38.5 nmol/L) at 3-5 d of lactation, 4.8 +/- 3.9 and 3.7 +/- 3.8 micrograms/L (50.0 +/- 4.6 and 38.5 +/- 39.6 nmol/L) at 7-10 d, 1.5 +/- 1.4 and 1.4 +/- 0.9 micrograms/L (15.6 +/- 14.6 and 14.6 +/- 9.6 nmol/L) at 14 d, 2.6 +/- 2.2 and 1.9 +/- 1.4 micrograms/L (27.1 +/- 22.9 and 19.8 +/- 14.6 nmol/L) at 1 mo, and 0.2 and 1.2 +/- 0.5 micrograms/L (2.1 and 12.5 +/- 5.2 nmol/L) at 2 mo. A statistical difference was found between term and preterm milk at 3-5 d of lactation. During lactation significant changes were found between the periods 3-5 d and 7-10 d, 14 d, 1 mo (p less than 0.01) and 2 mo (p less than 0.05) of lactation and between 7-10 d and 14 d (p less than 0.05). According to the requirements of the preterm infant, a supplementation of 2-3 micrograms.kg-1.d-1 by enteral route is suggested.

Heterogeneity of extrastriate visual areas and multiple parietal areas in the macaque monkey.

The definition of visual areas remains a key problem in the effort to elucidate cortical functions. Visual areas vary along a number of dimensions and are increasingly difficult to define according to traditional criteria at higher levels of the hierarchy. Three recently discovered areas in monkey parietal association cortex illustrate a new approach to this problem. Their definition depends on assessment of neuronal response properties in the alert, behaving animal combined with precise reconstruction of recording sites. This approach permits recognition of functionally distinct areas in the absence of retinotopic maps.

Deep dysphasia in a case of phonemic deafness: role of the right hemisphere in auditory language comprehension.

Deep dysphasia, an analogue of deep dyslexia in the auditory modality is a rare and peculiar pattern of repetition disturbance, which has been used to validate Morton's (Deep Dyslexia, pp. 189-196. Routledge & Kegan Paul, London, 1980) logogen theory. Such a case is reported here in which there was strong evidence of destruction of the left temporal lobe auditory areas. Examination of linguistic performance emphasized levels of auditory speech decoding. It was found that this patient had a profound phonemic discrimination deficit, yet could accomplish many lexical operations. It is argued that this case, in which a left temporal lobe lesion was associated with impaired phonological analysis, provides evidence that deep dysphasia may reflect the right hemisphere's non-phonological mode of speech processing.

Detection of viral, Chlamydia pneumoniae and Mycoplasma pneumoniae infections in exacerbations of asthma in children.

BACKGROUND: A high frequency of virus infections has been recently pointed out in the exacerbations of asthma in children. OBJECTIVES: To confirm this, using conventional and molecular detection methods, and expanding the study to younger children. STUDY DESIGN: One hundred and thirty-two nasal aspirates from 75 children hospitalized for a severe attack of asthma were studied (32 infants, mean age 9.1 months; and 43 children, mean age 5.6 years). According to the virus, a viral isolation technique, immunofluorescence assays (IFA) or both were used for the detection of rhinovirus, enterovirus, respiratory syncytial (RS) virus, adenovirus, coronavirus 229E, influenza and parainfluenza virus. Polymerase chain reaction (PCR) assays were used for the detection of rhinovirus, enterovirus, RS virus, adenovirus, coronavirus 229E and OC43, Chlamydia pneumoniae and Mycoplasma pneumoniae. RESULTS: Using IFA and viral isolation techniques, viruses were detected in 33.3% of cases, and by PCR techniques, nucleic acid sequences of virus, Chlamydia pneumoniae and Mycoplasma pneumoniae were obtained in 71.9% of cases. The combination of conventional and molecular techniques detects 81.8% of positive samples. Two organisms were identified in the same nasal sample in 20.4% of the cases. The percentage of detections was higher (85.9%) in the younger group than in the other (77%). The most frequently detected agents were rhinovirus (46.9%) and RS virus (21.2%). Using PCR rather than conventional techniques, the detection rates were increased 5.8- and 1.6-fold in rhinovirus and RS virus infections, respectively. The detection levels of the other organisms are as follows: 9.8, 5.1, 4.5, 4.5, 4.5, 3.7, and 2.2% for enterovirus, influenza virus, Chlamydia pneumoniae, adenovirus, coronavirus, parainfluenza virus, and Mycoplasma pneumoniae, respectively. CONCLUSION: These results confirm the previously reported high frequency of rhinovirus detection in asthmatic exacerbations in children. They also point out the frequency of RS virus detection, and emphasize the fact that PCR assays may be necessary to diagnose respiratory infections in asthma.

Spatial representations for action in parietal cortex.

Parietal cortex contains multiple representations of visual space. Single neurons in area LIP encode attended locations relative to the fovea, while some VIP neurons encode stimulus location relative to the head and some MIP neurons may encode location relative to the arm. These multiple representations are tailored to guide specific kinds of actions: eye movements, head movements and arm movements, respectively. The function of parietal cortex is to signal the location of attended objects relative to the observer. It does so in order to allow the organism to act on its environment. The many different kinds of actions that can be performed are likely to be supported by these very different kinds of spatial representations.

Eye position encoding in the macaque ventral intraparietal area (VIP).

Many neurons in area VIP encode the location of visual stimuli in a non-retinocentric frame of reference. In this context the question needed to be addressed whether the underlying coordinate transformation of the incoming visual signals could be generated within area VIP or whether this information would have to arrive from other areas. We tested 74 neurons in area VIP of two awake monkeys for an influence of eye position while animals performed a fixation task. More than half of the neurons (40/74) revealed an eye position effect. At the population level, however, this effect was balanced out. We suggest that local connections within area VIP could be used to generate an encoding of visual information in a non-retinocentric frame of reference.

Congruent unilateral impairments for real and imagined hand movements.

The chronometry of imagined and actual movements was investigated in a patient with a unilateral lesion of the motor cortex. Motor imagery generated highly accurate estimates of motor performance in a variety of situations, reflecting the hypokinesia of the contralesional hand. There were parallel increases in mental and actual movement times from proximal to distal limb segments. Bimanual movements adopted the slower speed of the impaired hand in both conditions. Imagined motor sequences to the beat of a metronome predicted the maximum speed reached in actual performance. Finally, visually guided pointing showed the same target-size effects in the imagery and movement conditions. The results are in agreement with the hypothesis that common cerebral motor representations are activated when imaging and planning voluntary movements.

Manual pointing to auditory targets: performances of right versus left handed subjects.

In order to test the existence of an hemispheric asymmetry at a basic level of spatial information processing, six right handed and six left handed normal subjects were submitted to a manual pointing task to auditory targets. Results showed a shift in perceived target position according to the hand used for pointing, a striking asymmetry between the two auditory hemispaces reflected in both groups in directional error and dispersion.

Audio-spatial deficits in humans: differential effects associated with left versus right hemisphere parietal damage.

In order to study auditory spatial localization in subjects with posterior damage involving the parietal lobe, we investigated their manual pointing performances to linguistic and white noise signals distributed over six sound sources situated in the anterior auditory field at ear level. The results showed: (1) A striking difference between patterns of deficits associated with right and left damage. In subjects with right damage, auditory localization deficits occurred in the horizontal plane, were manifested as restrictions in the peripheral left auditory hemifield and tended to be related to left visual neglect. In subjects with left damage, auditory localization deficits occurred in the entire auditory field in the horizontal as well as vertical planes, and they were particularly strong in the antero-frontal region. (2) One subject with right damage and visual neglect but no left auditory spatial restriction, showed deficits in the right hemifield where sound source location tended to be overestimated. This subject also showed a better discrimination of the origin of a white noise than of a linguistic signal. Results are discussed in terms of hemispheric asymmetries of function.

A selective impairment of hand posture for object utilization in apraxia.

This study reports the case of an apraxic patient who was impaired in all aspects of gestural behavior following bilateral posterior parietal cortex lesions. The main impairment concerned manual prehension of objects during their utilization. The deficit contrasted with both normal movement trajectories of the arm during execution of such gestures, and with accurate manual prehension in the context of simple reaching movements. Although recognition of gestures and pantomimes made by the examiner was preserved, the patient showed a striking inability to visually discriminate or describe manual prehension associated with object utilization. We thus propose the existence of specialized cortical mechanisms for the representation and activation of the postural schemata of the hand required for complex actions.

Blood and urinary amino acids in children receiving total parenteral nutrition.

Plasma concentrations and urinary outputs of amino acids were estimated in nineteen patients receiving intravenous hyperalimentation to evaluate the adequacy of dosage and composition of the infusates for the maintenance of normal blood concentrations of essential amino acids. The use of high concentrations of branched chain amino acids seems to be appropriate for valine and isoleucine but not for leucine. The high concentration of cysteine in the infusates used induces a very high urinary excretion of cysteine and cystine and are ineffective to bring the decreased plasma cystine levels back to normal.