Showing papers by "Paris Descartes University published in 1994"

A second locus for Marfan syndrome maps to chromosome 3p24.2-p25.

Abstract: Marfan syndrome (MFS) is an autosomal dominant connective-tissue disorder characterized by skeletal, ocular and cardiovascular defects of highly variable expressivity. The diagnosis relies solely on clinical criteria requiring anomalies in at least two systems. By excluding the chromosome 15 disease locus, fibrillin 1 (FBN1), in a large French family with typical cardiovascular and skeletal anomalies, we raised the issue of genetic heterogeneity in MFS and the implication of a second locus (MFS2). Linkage analyses, performed in this family, have localized MFS2 to a region of 9 centiMorgans between D3S1293 and D3S1283, at 3p24.2–p25. In this region, the highest lod score was found with D3S2336, of 4.89 (θ=0.05). By LINKMAP analyses, the most probable position for the second locus in MFS was at D3S2335.

Caractérisation du timbre des sons complexes.II. Analyses acoustiques et quantification psychophysique

Abstract: A timbre space represents the mental organization of sound events at equal pitch, loudness, and duration. The geometric distance between two timbres corresponds to their degree of perceived dissimilarity. The dimensions of such a three-dimensional space, established by Krumhansl [1] for a set of 21 synthesized sounds, were investigated with respect to their acoustic characteristics. Several acoustical parameters based on the temporal and frequency properties of the sounds were calculated. The high degree of correlation of several parameters with the perceptual axes lend support to previous interpretations of the qualitative character of two perceptual dimensions and their semantic attributes. The perceptual dimensions «brightness» and «rapidity of attack» turn out to be quantitatively explainable by the center of gravity of the sound spectrum (CGS) and the rise time on a logarithmic scale (LTM), respectively. The third dimension, initially called «spectral flux» corresponds partially to the standard deviation of the timeaveraged harmonic amplitudes from a spectral envelope (IRR). A new verbal descritor, «spectral fine structure» seems to fit better with the results of acoustic analyses

Functional relationship between mast cells and C-sensitive nerve fibres evidenced by histamine H3-receptor modulation in rat lung and spleen

Abstract: 1. Mast cell populations in rat lung and spleen were characterized by the presence of two specific protease markers, rat mast cell protease I and II, using both histochemical and radioimmunoassay techniques. Three mast cell populations with different size, morphology, and localization were found in lung and spleen and were identified according to the expression of rat mast cell protease I (RMCPI+) or rat mast cell protease II (RMCPII+) or of both proteases (RMCPI/II+). 2. All three mast cell types were in the vicinity of calcitonin-gene-related-peptide-immunoreactive (CGRP+) nerve fibres in controls as well as in rats infected by Nippostrongylus brasiliensis in which a large increase in the number of both RMCPII+ and RMCPI/II+ mast cells was found. Ablation of the CGRP+ fibres by neonatal treatment with capsaicin resulted in a marked increase in the number of RMCPII+ and RMCPI/II+ cells in lung and, even more, in spleen of adult rats. 3. The interaction of mast cells with CGRP+ C-fibres was assessed pharmacologically by evaluation of the effects of histamine H3-receptor ligands known to act on various types of nerve endings, including those of C-fibres. The effects of H3-receptor ligands were assessed in controls, nematode-infected rats and neonatally capsaicinized rats. Mast cell activity was evaluated by measurement of [3H]histamine synthesis from [3H]histidine. In control rats, administration of the H3-receptor agonist (R)-alpha-methylhistamine and antagonist thioperamide, decreased and enhanced respectively [3H]histamine synthesis in lung and spleen, indicating a tonic control of mast cell activity by histamine via H3-receptors. Such effects were not found in the jejunum, although RMCPII+ mast cells are in close apposition with neuropeptide-containing fibres. The effects of the H3-receptor agents were maintained in lung and spleen of nematode-infected rats, but were almost suppressed in capsaicinized rats. 4. It is concluded that the control of mast cells by histamine acting at H3-receptors involves neuropeptide-containing nerves and presumably reflects the operation of a local neuron-mast cell feedback loop controlling processes such as 'neurogenic inflammation'. This loop still functions when mast cells proliferate in an inflammatory condition. These observations suggest that the use of histamine H3-receptor agonists may constitute a novel therapeutic approach to limit excessive inflammatory responses resulting from dysregulation of this feedback loop.

Langerhans' cell histiocytosis cells are activated Langerhans' cells

Abstract: Langerhans' cell histiocytosis (LCH) is characterized by the presence of large mononucleated cells, associated with inflammatory cells. The Langerhans' cell (LC) lineage of the mononucleated cells is suggested by the presence of Birbeck granules and the expression of CD1a. We investigated the presence of 14 markers expressed by normal LCs in vitro. Nine skin and one lymph node frozen biopsies of LCH children were analysed by in situ immunohistochemistry. The data were compared with six skin and five lymph node frozen biopsies. LCH cells of the ten samples were positive for all 14 LC markers. We observed three different groups of markers, according to the respective staining of normal LCs and LCH cells. Group 1 included DR, DQ, CD1a, CD1c, and ICAM-3. Markers of group 1 were present on the majority of both normal LCs and LCH cells. Group 2 included CD1b, CD4, LFA-1, LFA-3, CD32, and CD68. Markers of group 2 were detected on the majority of LCH cells, but only on a fraction of normal LCs. Group 3 included CD11b, CD24, and B7/BB1. Markers of this group were detected on LCH cells, but not on normal LCs. This in situ immunohistochemical study confirms that LCH cells belong to the LC lineage. The different clinical LCH syndromes had the same immunohistochemical staining. The expression of some markers of groups 2 and 3 is known to be related to the activation of LCs in vitro. Our study suggests that LCH cells are activated LCs.

The Computation of Contour Information in Complex Objects

Abstract: Perceptual organisation, and especially the computation of contour information, has been the object of considerable interest in the last few years. In the first part of the paper we review recent accounts on the mechanisms involved in the processing of contour. In the second part we report an experiment designed to examine (1) how physical parameters such as spatial proximity and collinearity of elements affect the integration of global contour in objects and (2) whether the activation of stored representations of objects facilitates the computation of contour. Incomplete forms varying in the spacing and the alignment of line segments on their contour were used as stimuli in a matching task. Subjects were asked to decide which of two laterally displayed figures matched a reference form presented previously. The matching target and the distractor were physically identical but differed in their orientation. In one condition the reference object was always an outline drawing of an object. In a second condition the reference object was either a complete object or a more or less identifiable incomplete form. Little variation in performance was found for forms having continuous and discontinuous contour up to a spacing of 5 pixels (10.8 min) between elements. Response times and errors increased abruptly beyond this limit. This effect occurred in the two conditions of reference stimulus, suggesting that the computation of contour information is more affected by physical constraints at early processes than by high-level processes involving activation of stored structural representations of objects.

Real-time sleep-wake scoring in the rat using a single EEG channel

Abstract: A new method of analysis of sleep in the rat based on the electrocorticogram (ECoG) is described. Three states, awake (W), nonrapid eye movement (NREM) and rapid eye movement (REM) sleep are automatically classified by the system. After amplification of the ECoG over a restricted bandwidth (3.18-25 Hz) and sampling at 512 Hz, the data are processed in 8-second epochs by a microcomputer, which generates three statistical and two harmonic variables. Each 8-second epoch is thus compressed into five numerical values occupying 10 bytes of memory. Epochs for each state of vigilance are identified by an expert observer to produce three reference models. The program classifies each epoch into the appropriate state by the least quadratic distance. The system was validated by comparing the results with a visual analysis of polygraph recordings. The agreement between the program and the two independent scorers for 24-hour tracings of six rats was 83% for REM sleep, 96% for W and 97% for NREM sleep.

Identification of two nuclear N‐acetylglucosamine‐binding proteins

Abstract: Using neoglycoproteins, lectins that recognize different sugars, including N-acetylglucosamine resi- dues, were previously detected in animal cell nuclei. We report herein the isolation of two N-acetylglucosamine-binding proteins from HL60 cell nuclei: i) a 22 kDa polypeptide (CBP22) with an isoelectric point of 4.5 was isolated for the first time and ii) a 70 kDa polypeptide with an isoelectric point of 7.8. This latter protein corresponds to the glucose-binding protein (CBP70) previously isolated, based on the following similarities: i) they have the same molecular mass, ii) they have the same isoelectric point, iii) they are recognized by antibodies raised against CBP70, and iv) both are lectins from the C group of Drickamer's classification. CBP7O appeared to recognize glucose and N-acetylglucosamine; however, its affinity for N-acetylglucosamine was found to be twice that for glucose. The presence in the nucleus of two nuclear N-acetylglucosamine-binding proteins and their potential ligands, such as 0-N-acetylglucosamine glycoproteins, strongly argues for possible intranuclear glycoprotein-lectin interactions.

Iodopolatinate visualization of phospholipids in rat incisor predentine and dentine, compared with malachite green aldehyde

Abstract: The iodoplatinate (IP) reaction, a selective method for visualization of phospholipids, was applied to the predentine and dentine of rat incisors and compared with malachite green aldehyde (MG) fixation/staining. Spot tests indicated (1) that IP specifically stains phospholipids, but not amino acids, displaying as do phospholipids, quaternary ammonium groups; and (2) phosphatidylserine and sphingomyelin were also stained by MGA. Although this reagent is known to interact with phosphorus, phosphoproteins remained unstained. In the rat incisor, an IP-positive network including granules and thin filaments was seen in predentine in the inter-collagen spaces, in many cases closely associated with collagen fibres and their periodic striations. In dentine, positively stained needle-like structures were located along individual collagen fibres, or at the surface of groups of collagen fibres. This staining pattern was unchanged on sections of material pretreated with acetone, whereas the staining was abolished or markedly reduced when the samples were treated either with chloroform/methanol or phospholipase C prior to the IP reaction. Pretreatment of the samples with hyaluronidase promoted subsequent diffusion of the staining. A very similar staining pattern was observed with MGA, in accordance with earlier reports. The present findings validate the histochemical results reported previously on the distribution and potential role(s) of phospholipids in dentine biomineralization.

Physicochemical and immunological comparisons between angiotensin I-converting enzymes purified from different mammalian species

Abstract: Angiotensin I-converting enzyme (ACE) was purified from lungs of pig, rat, monkey and human for comparison of its physicochemical, enzymatic and immunological properties. The protocol involved three chromatographic steps after detergent extraction, i.e. DEAE-Spherodex ion exchange, lisinopril-Sepharose affinity and Superose 12 HPLC, plus Mono-Q HPLC for monkey ACE. Purified ACE's presented numerous homologies: in particular, closely similar specific activities, catalytic efficiencies, Km's, optimal pH and chloride activations; the molecular weights were about 170 kDa by SDS-PAGE and 320 kDa by gel-filtration on Superose 12; the isoelectric points were about 4.5-4.7. Specific polyclonal antibodies recognized the antigen (porcine ACE) as well as rat, monkey and human ACEs. In contrast, three monoclonal antibodies (F02.4.1, F01.1.3 and F03) produced against porcine ACE showed some differences: they only reacted with pig enzyme and only one (F0.2.4.1) was anticatalytic. Moreover, the cross-reactivity judged on ELISA with porcine ACE characterized different epitopes specific for the porcine enzyme. In particular, the binding of F02.4.1 was not diminished by previous treatment with saturating concentrations of synthetic competitive ACE inhibitors. Thus, the extrapolation to human of data obtained on animal models should be possible at least for pharmacological and medical trials.

LDV assessment of methyl nicotinate biological response in aqueous solution against that of a w/o microemulsion system.

Abstract: Synopsis The aim of this work was to check if the specific microstructure of a water/oil nonionic microemulsion could induce a modification of the bioavailability of a probe (methyl nicotinate). The vasodilatory drug effects were recorded by laser doppler velocimetry in vivo, in man. The results show a quicker activity, and a better release of the drug in the microemulsion, than in the well-known kinetics of an aqueous solution.

Passage des antibiotiques dans le lait maternel

Abstract: Resume Au cours de l'allaitement, les antibiotiques sont administres pour traiter une infection maternelle. Le choix des antibiotiques va se porter sur des molecules qui s'eliminent peu dans le lait et qui sont peu susceptibles d'entrainer des effets indesirables pour le nouveau-ne. La plupart des antibiotiques passent dans le lait. Le plus souvent, les quantites auxquelles l'enfant est expose sont faibles et le traitement antibiotique ne constitue pas une contre-indication a l'allaitement. Toutefois, le risque d'effets indesirables, parfois peut-etre plus theorique que pratique, fait eviter l'allaitement au cours du traitement antibiotique ou, plus souvent, fait eliminer du choix l'antibiotique a risque : principalement, les phenicoles, les tetracyclines, les sulfamides, la clindamycine, la lincomycine, les aminosides et certains antiseptiques urinaires.

Incidence of narcissism in adolescent thought processes

Abstract: Some normally intelligent children succeed in school until they reach adolescence and start to fail in academic achievements. These adolescents display some features which confirm the role of adolescent changes in the phenomenon. This article presents the theoretical considerations, the hypotheses, the methods and the findings of a study exploring the impact of the narcissistic challenges on thought processes and on the mechanism of sublimation. The study involves two groups of adolescents, succeeding and not succeeding in school who underwent a psychological assessment including the WAIS or WISC-R, the Rey Figure, the Rorschach and the TAT. The relevant test factors are presented. Findings show that narcissistic disorders brought about by adolescence has a different impact according to the previous quality of narcissism. It can have a traumatic impact enabling creativity, with varied effects on academic achievement, or a paralyzing impact on thought. It is thus confirmed that adolescence is revealing of the past.

The effect of situation familiarity on the establishment of co-references between mother and infant

Abstract: The purpose of this study was to determine whether the familiarity or the novelty of play objects available during mother-infant interaction has an effect on the mother's ability to capture and maintain the infant's attention. Twelve mother-infant dyads with 5- and 9-month-old infants were filmed during two 5-minute sessions with familiar or unfamiliar toys. Changes in the infant's visual orientation preceded by a maternal behaviour within a 3-sec interval were studied. In the familiar toy situation, the infants focused more frequently on the maternal referent than with the unfamiliar toys. The mother's verbal and non-verbal interventions were more effective at initiating and maintaining co-reference, because the infant was more frequently in an receptive state. Conversely, when the toys were unfamiliar, the baby was often the initiator. Unfamiliar objects, which appear more attractive, may compete with the mother's attempts to gain the child's attention.

Discrimination de tempo chez des bébés de 4 mois

Abstract: The present experiment tested the tempo discrimination abilities of four month-old infants, as a function of tempo range, to investigate whether a similar range of tempo sensitivity is found in infants as in adults. Isochronous auditory sequences were presented with a tempo of 100, 300 or 600 ms inter-onset interval (IOI). Infants were conditioned to associate the auditory sequence and a red light. In an habituation phase, sequences of equal IOI were presented successively, until an habituation criterion was reached. Then for the next three trials, 24 infants (mean age 4;7) heard a sequence with a 15% faster IOI, and the control group of 15 infants (mean age 4;18) heard the unchanged standard IOI. A reaction to novelty, expressed by longer visual fixations to the light was expected in the experimental group if the two tempi were discriminated. The results show that infants are sensitive to a 15% IOI increment for habituation IOI of 300 and 600 ms, but not for 100 ms IOI. Infants discriminate isochronous sequences on the basis of tempo variations, in the same tempo range as adults. These data support the hypothesis that regularity extractor mechanisms are functional at the age of 4 months

Islets of langerhans and pancreas transplantation tomorrow

Abstract: Pancreatic tissue grafting as a substitution for insulin deficiency of diabetes is by far the most physiological therapeutic approach of the disease. Both islets and pancreatic gland have been successfully implanted in experimental animal diabetes and in patients, resulting in full normalisation of glucose homeostasis and, in animals, prevention of chronic complications. The need for heavy immunosuppressive drugs is a major drawback not yet overcome and auto and cotransplantation have limited indications. The future lies in intensive research aiming at the discovery of alternative strategies to avoid immunosuppression. Immunoprotection and immunoalteration are attempts to hide or delete harmful pancreatic antigens. Perfusion of MHC soluble donor antigens, anticytokine treatment, xenogenic bone marrow chimerism, use of genetically modified islets, intrathymic islet graft to induce donor specific unresponsiveness are among the numerous trials in progress. Parallely islet banking by cryopreservation and development of a physiological beta cell line are also needed and improving but the absence of a biological marker of pancreatic tissue rejection is a cruel lack. Even only one achievement among these trials could be enough to see the explosion of the development of pancreatic tissue graft. While waiting for that success, it could be wise to accept that such a graft can already bring an amelioration with partial insulin restoration before being able to give a complete cure. We have also to keep in mind that animal models are far away from diabetic patients and much more easy to treat. It is not an unrealistic dream to claim that a xenogenic pancreatic tissue graft without any immunosuppression will be available very soon for every diabetic patient.

Sensibilité au tempo en audition : mesure et modélisation

Abstract: The ability of listeners to detect slight changes in tempo of isochronous auditory sequences was investigated by measuring differential thresholds for tempi (with interonset intervals IOI ranging from 100 to 1500 ms) of sequences varying in the number of intervals tbey contain. A multiple-look model presented previously [3] predicts that sensitivity increases as the number of intervals in the sequence increases, since multiple observations afford the elaboration of a more precise mental representation involving the coding of the average duration and degree of dispersion of the intervals in the sequence. The results of the present study indicate that an additional parameter, that of the total duration of the sequence is also involved: the faster the tempo of the sequence, the more intervals are necessary to obtain the lowest JNDs. The upper limit of this «temporal window» is about one second for sequences of 50 to 300 ms IOI and about 2.5 seconds for sequences of 500 to 1500 ms IOI

Computational modelling of auditory streaming phenomena

Abstract: A computer model is described that uses simple physiological principles that operate mainly at a peripheral level to account for perceptual coherence among successive pure tones of changing frequency. Using a single set of parameter values, the model is able to reproduce a number of fundamental auditory streaming phenomena. These include the build-up of auditory stream segregation over time, and the temporal coherence and fission boundaries of human listeners. Whereas these streaming phenomena are generally accounted for in terms of a high-level auditory scene-analysis process, the success of the model in reproducing experimental data obtained from humans justifies the potential value of a low-level analysis for explaining auditory grouping phenomena, and suggests that some auditory grouping may be the product of low-level auditory processing

Liaison Et Information Dans Les Tableaux De Contingence: Comnientaire De L'Article De Frederic Michel:

Abstract: Links and Information in Contingency Tables - Corrimentary on Frederic Michel's Article. Frederic Michel's article ("Link Strength and Volume of Information in Contingency Tables- Two Problems of Measure in Data Analysis") published in this Issue, proposes solutions to a certain number of problems. lt would be helpful for research on these problems to sltuate the author's solutions in the framework of preceding research on the question.