Showing papers by "Collège de France published in 1983"
TL;DR: In this article, the results of two searches made on data recorded at the CERN SPS Proton-Antiproton Collider were reported, one for isolated large-E T electrons, the other for large E T neutrinos using the technique of missing transverse energy.
957 citations
TL;DR: 3H-PAT seems to be a useful ligand for studying the biochemical and pharmacological characteristics of presynaptic autoreceptors in selected regions of rat brain.
Abstract: Binding studies with appropriate labelled ligands have revealed the existence of two types of serotonin (5-HT) receptor, 5-HT1 and 5-HT2, in the central nervous system of mammals1. The 5-HT1 type is characterized by a higher affinity for agonists than for antagonists, whereas the 5-HT2 type binds preferentially to antagonists. However, neither of these receptor types apparently corresponds to the presynaptic autoreceptor controlling 5-HT release2. In an attempt to identify the presynaptic autoreceptor directly, we synthesized the tritiated derivative of 8-hydroxy-2-(di-n-propylamino) tetralin (PAT), a new tetralin derivative with potent 5-HT agonist properties3 and carried out binding studies with rat brain membranes. As we report here, in the hippocampus, the properties of 3H-PAT binding sites correspond closely to those of 5-HT1 sites. In contrast, in the striatum, 3H-PAT binding sites exhibit a subcellular distribution and pharmacological characteristics usually associated with presynaptic autoreceptors. Furthermore, a marked loss of 3H-PAT binding sites occurs in the striatum (but not in the hippocampus) after the selective degeneration of serotoninergic fibres in 5,7-hydroxytryptamine (5,7-HT)-treated rats. Conversely, the sprouting of additional 5-HT terminals in the brain stem of adult rats treated at birth with 5,7-HT is associated with an increased density of 3H-PAT binding sites in this region. 3H-PAT thus seems to be a useful ligand for studying the biochemical and pharmacological characteristics of presynaptic autoreceptors in selected regions of rat brain.
762 citations
TL;DR: In this paper, the signature of a two-body decay of a particle of mass ∼ 95 GeV/c2 was observed, which fit well with the hypothesis that they are produced by the process p + p → Z 0 + X (with Z 0 → l + + + l − ), where Z 0 is the Intermediate Vector Boson postulated by the electroweak theories as the mediator of weak neutral currents.
733 citations
483 citations
TL;DR: It is shown that the 70K early two-cell-specific proteins are identical to two of the mouse heat shock proteins, HSP 68 and HSP 70.
Abstract: In many species, the early post-fertilization development of the egg appears to occur mainly under maternal control and does not require transcription of the embryonic genome. In the mouse this situation is restricted to the one-cell stage; activation of the embryonic genome occurs at the late two-cell stage and results in a drastic change in the spectrum of proteins synthesized. This activation is preceded by a decrease in the overall synthesis of proteins at the end of the one-cell stage and the appearance, at the early two-cell stage, of a set of new polypeptides of molecular weight approximately 70,000 (70K) (refs 2, 8, 9). This can be compared with the series of events that occur after hyperthermia in differentiated cells. Heat shock results in an arrest of most transcription and translation; subsequently, expression of a limited set of genes, the heat shock genes, precedes the overall reactivation of cellular genome. Here we show that the 70K early two-cell-specific proteins are identical to two of the mouse heat shock proteins, HSP 68 and HSP 70.
382 citations
TL;DR: It is shown here that committed precursors of peripheral neurons are present in the crest before the migration of its cells has started, and that conditions stimulating proliferation of crest cells are incompatible with promotion of neuronal differentiation and vice-versa.
195 citations
TL;DR: Data in the literature together with the own results suggest that the same three HSP are also spontaneously expressed in high amounts in the early mouse embryo.
Abstract: When submitted to a heat-shock, mouse embryonal carcinoma (EC) and fibroblast cells show very different behavior. All the EC cells so far analyzed express very high levels of several heat-shock proteins (HSP) in the absence of stress and independent of their origin and culture conditions. In such cells, the 89-kd, 70-kd and 59-kd HSP are the most prominent proteins after actin. In addition, the 89-kd and 59-kd HSP are not stimulated by an arsenite shock in contrast to what is observed with fibroblasts or cells of the parietal yolk sac type. Arsenite induces the synthesis of a 105-kd polypeptide in fibroblasts but not in EC cells. In vitro differentiation of F9 cells induced by retinoic acid and dibutyryl cAMP is accompanied by a decrease in the spontaneous relative abundance of HSP and restores the arsenite-induced synthesis of the 105-kd polypeptide. EC cells are usually believed to be similar to inner cell mass cells of mouse blastocyst. Furthermore, data in the literature together with our own results suggest that the same three HSP are also spontaneously expressed in high amounts in the early mouse embryo.
178 citations
TL;DR: Results show that the peripheral ganglia are differentially sensitive to the presence of the neural tube and the notochord, among the various ganglia of the peripheral nervous system, spinal and sympathetic Ganglia are the only ones which require the existence of these axial structures.
169 citations
TL;DR: In this article, a sample of 52 Intermediate Vector Boson decays in the ( v e e) channel is described. They were produced at the CERN SPS Collider for an integrated luminosity of 0.136 pb −1.
144 citations
TL;DR: Biologic investigations of sexual dimorphism and sex determination were initiated in the last century and histo-chemical and histoenzymological data were used to define the ontogenesis, localization, and activity of steroidogenic cells in the gonads, both during embryonic development and after hatching.
140 citations
TL;DR: In this article, the authors measured the total transverse energy spectrum for pp collisions at s 1 2 = 540 GeV up to ΣE T = 130 GeV in the pseudo-rapidity range.
TL;DR: It is found that soluble TH from the rat striatum could be activated by a Ca2+-dependent process in optimal conditions for producing the phosphorylation of proteins and this activation corresponded exactly to that resulting from the incubation of striatal slices in K+-enriched medium.
Abstract: Tyrosine hydroxylase (tyrosine 3-monoxygenase, EC 1.14.16.2, TH) catalyses the rate limiting step of catecholamine biosynthesis, In vitro, TH from central dopaminergic1–4 as well as from central5,6 and peripheral6,7 noradrenergic neurones can be activated by a cyclic AMP-dependent phosphorylation process and several authors7–9 have proposed that this process can be responsible for the in vivo activation of TH resulting from the electrical stimulation of these neurones. However, this is unlikely to be the case for TH in central dopaminergic neurones because depolarization produces an enzyme activation which is additive with that due to the cyclic AMP-dependent phosphorylation process10–12. In the case of tryptophan hydroxylase in central serotoninergic neurones, recent evidence indicates that a Ca2+-dependent instead of a cyclic AMP-dependent phosphorylation process is responsible for the increased enzyme activity triggered by depolarization13. This finding led us to investigate whether a Ca2+-dependent phosphorylation process also accounts for the activation of TH inside depolarized dopaminergic terminals. We found that soluble TH from the rat striatum could be activated by a Ca2+-dependent process in optimal conditions for producing the phosphorylation of proteins. This activation corresponded exactly to that resulting from the incubation of striatal slices in K+-enriched medium and indeed TH activity from depolarized dopaminergic terminals could not be further stimulated by Ca2+-dependent phosphorylating conditions. In contrast, in situ TH activation by cyclic AMP-dependent phosphorylation (triggered by dibutyryl cyclic AMP or forskolin) did not prevent subsequent stimulation by Ca2+-dependent phosphorylation. These findings suggest that TH activation in depolarized dopaminergic terminals involves a Ca2+-dependent phosphorylation process similar to that controlling tryptophan hydroxylase activity in serotoninergic neurones.
TL;DR: Binding characteristics of 125I‐labeled Bolton‐Hunter substance P (125I‐BHSP), a radioactive analogue of substance P, were studied with a crude synaptosomal fraction of the rat brain and a specific binding that was saturable, reversible, and temperature dependent was demonstrated.
Abstract: :
Binding characteristics of 125I-labeled Bolton-Hunter substance P (125I-BHSP), a radioactive analogue of substance P, were studied with a crude syn-aptosomal fraction (P2) of the rat brain. A specific binding of 125I-BHSP that was saturable, reversible, and temperature dependent was demonstrated. Under the conditions of the binding assay (20°C, 5 min), nonspecific binding represented no more than 25% of total binding, and in contrast to [3H]dopamine 125I-BHSP was not taken up within synaptosomes by a ouabain-sensitive process. Scatchard analysis indicated the existence of a single population of noninteracting sites with a high affinity (KD, 470 pM) and a low-density (Bmax, 13 fmol/mg protein). Substance P and different substance P analogues were tested for their competitive potencies in inhibiting 125I-BHSP binding to synaptosomes. (Tyr8) substance P, substance P, and BHSP strongly inhibited 125I-BHSP specific binding. Among various tachykinins, physalaemin was the most potent (one fourth the potency of substance P). When substance P C-terminal fragments were tested for their ability to compete with 125I-BHSP binding, a good relationship was found between competitive activity and peptide length. N-terminal fragments of substance P were ineffective. However, (nor-Leu11)substance P and the methyl ester of substance P1-11 slightly reduced 125I-BHSP binding. (D-Pro2, D-Phe7, D-Trp9) substance P and (D-Pro2, D-Trp7,9)substance P, two substance P antagonists, were also tested. (D-Pro2, D-Trp7,9) substance P was the only one to inhibit 125I-BHSP binding even slightly. Results were compared with those previously obtained concerning 125I-BHSP binding to mesencephalic embryonic cells in primary cultures using similar conditions for the binding assay.
TL;DR: In this article, high statistics samples of dimuon events (∼35,000) produced from π± on platinum target in the mass interval 4.2≦Mμμ≦8.5 GeV at 150, 200 and 280 GeV/c.
Abstract: We have studied high statistics samples of dimuon events (∼35,000) produced from π± on platinum target in the mass interval 4.2≦Mμμ≦8.5 GeV at 150, 200 and 280 GeV/c. The π structure function is obtained by a fit ofd2σ/dx1dx2 to π+ and π− data. At 200 GeV, the simultaneous use of π+ and π− data allows a separate determination of the valence and sea structure functions of the π. Furthermore, the 150 and 280 GeV data allow an accurate determination of the shape of the valence structure function and give an estimate of its evolution betweenQ2=25 and 50 GeV2.
TL;DR: In this article, a detailed study of hadronic jets obtained in a data sample taken in the UA1 detector with a localized transverse energy trigger is presented, and the average shape of jets in terms of energy and charged particle content is discussed.
TL;DR: In this paper, the authors consider a porous solid, partially filled with a nonwetting fluid, just above the injection threshold: the injected regions have the topology of the infinite cluster in a percolation problem, and they split into a backbone part plus dead ends.
Abstract: We consider a porous solid, partially filled with a non-wetting fluid, just above the injection threshold: the injected regions have the topology of the infinite cluster in a percolation problem, and they split into a ‘backbone’ part plus ‘dead ends’. Under a steady Darcy flow, a dye molecule moves by convection on the backbone, and by molecular diffusion on the dead ends. The process has some similarity with solute transport in chromatographic columns. However, because the ‘dead ends’ have a broad distribution of sizes, special singularities may occur, which are reminiscent of non-Gaussian transport for charge carriers in amorphous semiconductors.We ultimately predict the existence of a well-defined diffusion coefficient D|| for motion parallel to the average flow, in the limit of slow molecular diffusion. We find the macroscopic flow velocity and Da the diffusion coefficient of an ‘ant’ on the infinite cluster (i.e. the macroscopic diffusion constant measured in the absence of flow).
TL;DR: In this article, it was shown that the monomer concentration profile Φ(x) for isolated polymer chains in a good solvent and in close proximity to an adsorbing wall exhibits a singular behaviour, i.e., Φ (x) ∼ (a/x) m, where a is a monomer dimension and m ≅ 1/3.
Abstract: We interpret some recent calculations of Eisenriegler, Kremer, and Binder [1], and related multi-critical results of Diehl and Dietrich [2]. They show that the monomer concentration profile Φ(x) for isolated polymer chains in a good solvent and in close proximity to an adsorbing wall exhibits a singular behaviour ; i.e., Φ(x) ∼ (a/x) m, where a is a monomer dimension and m ≅ 1/3. Taking into account the proximal exponent m, we correct earlier scaling results [3, 4] for the interfacial tension of semi-dilute polymer solutions in good solvents. We also find good agreement with a recent result by Ishinabe [5] on the single chain energy.
TL;DR: The ability to synthesize and degrade ACh is expressed at least in some neural crest cells at an early stage of development, as indicated by the presence of the specific AChE all along the neural axis.
TL;DR: In this paper, the existence of two new mesophases in the two enantiomers of 1 (methyl)-heptyl terephthalidene bis amino cinnamate is established.
Abstract: Microscopical, miscibility and X-ray studies establish the existence of two new mesophases in the two enantiomers of 1 (methyl)-heptyl terephthalidene bis amino cinnamate. In one of this two mesophases the two enantiomers do not exhibit a total miscibility range; while for the second the untwisted form observed with the racemic mixture has a higher temperature range of stability than the twisted form observed for the pure enantiomers. Information about the structures of the two phases is given and a comparison is made with the S*C and SD phases. Nevertheless the location of these two phases in the sequence of the presently known calamitic mesophases is not yet completely established.
TL;DR: It is demonstrated that each of the four fatty acids studied was incorporated into phospholipids, and among several combinations of fatty acids, only 20:4 and 22:6, when added to the culture in a ratio of 2:1, restored a fatty acid profile similar to controls.
Abstract: The biochemical and morphological effects of polyunsaturated fatty acids on fetal brain cells grown in a chemically defined medium were studied. Fetal brain cells were dissociated from mouse cerebral hemispheres taken on the 16th day of gestation. After cells had grown in chemically defined medium for 8 days, the proportion of polyunsaturated fatty acids of cultured cells was only one-half of that observed at day 0 and about 1.5 times less than that of cells grown in serum-supplemented medium. Fatty acid 20:3(n-9) was present in cultured cells grown in either chemically defined or serum-supplemented medium, demonstrating the deficiency of essential fatty acids. The reduced amount of polyunsaturated fatty acids in cells grown in the chemically defined medium was balanced by an increase in monounsaturated fatty acids. The saturated fatty acids were not affected. When added at the seeding time, linoleic, linolenic, arachidonic, or docosahexaenoic acid stimulated the proliferation of small dense cells. Besides, we demonstrate that each of the four fatty acids studied was incorporated into phospholipids. Adding fatty acids of the n-6 series increased the content of n-6 fatty acids in the cells, but also provoked an increase in the n-3 fatty acids. Among several combinations of fatty acids, only 20:4 and 22:6, when added to the culture in a ratio of 2:1, restored a fatty acid profile similar to controls (i.e. in vivo tissue taken at postnatal day 5).
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01 Jan 1983TL;DR: In this paper, the main purpose of this chapter is to combine ==================¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯DIFFERENTIAL ALGEBRA,============¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ORDER,¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯DISEQUENCE,DESCAPE,DESCAPE,DESPAGE,DESPACE,DESSAGE, DESPAGE and DESSAGEGE GEOMETRY in a unique framework, called Difference Differential AlgebRA.
Abstract: The main purpose of this Chapter is to combine
DIFFERENTIAL ALGEBRA,
DIFFERENTIAL GEOMETRY, and
ALGEBRAIC GEOMETRY
in a unique framework, called DIFFERENTIAL ALGEBRAIC GEOMETRY.
TL;DR: It is concluded that in the conditions of the back-transplantation experiments, the postmitotic neurons contained in the donor ganglion do not survive and indicates that besides sensory neuron precursors the embryonic DRG cell population also contains precursor cells for the autonomic differentiation pathway.
TL;DR: Dopaminergic cell bodies surrounded by met-enkephalinergic varicosities were seen in most groups, particularly in the lateral substantia nigra and medioventral tegmentum, which was reminiscent of the distribution of neostriatal and pallidal afferents in rodents.
TL;DR: In this article, the authors used the form exp (bt ) with b = 17.1 ± 1.18 GeV su 2 and b = 13.7 ± 0.2 GeV −2 for | t | = 0.21−0.04 t 2.
TL;DR: When measured in post-mortem human control brains, a significant reduction in the levels of both peptides was found in the pallidum and putamen whereas only Met5-enkephalin levels were decreased in the substantia nigra and ventral tegmental area, suggesting that Met5 and Leu5 may be located in different neuronal populations in the human brain.
TL;DR: In this article, the diffusion coefficient of a polymer solution in cyclohexane solvents is investigated in three regimes: the many chain regime (qg q 1/03BE), the entangled single chain regime and the single-chain regime.
Abstract: 2014 A polymer solution forms a transient network of lifetime Tr. In good solvents, the mesh size l is identical to the correlation length 03BE for the fluctuations of the monomer concentration c. But in « 03B8 » solvents (where the pair interaction vanishes), / is much smaller than 03BE. The dynamics involve then two quantitatively very different elastic moduli E : :1) at low frequencies, E = E0 = kT/03BE3 N c3 is small; 2) at higher frequencies, E = E gel kTc2 and Egel > E0. This leads to two modes in photon-beat experiments at wave vectors q larger than a certain value qg, the high frequency mode being the gel mode. Although this gives only a small fraction of the total scattered light, it still dominates the slope of the dynamical structure factor S(q, t) at small times. We investigate the corresponding diffusion coefficient D g in the three regimes : a) « many chain » regime (qg q 1/03BE), Dg ~ kT/6 03C0~s a is very high (a is a monomer size and ~s the solvent viscosity) ; b) entangled « single chain » regime (03BE-1 q l-1 ), Dg(q) ~ 1/q; c) disentangled « single chain » regime (ql > 1), Dg ~ q. The regimes b) and c) could be observed only in neutron experiments. But the cross-over from a) to b) could explain certain photon-beat results on PS in cyclohexane. J. Physique 44 (1983) 39-43 JANVIER 1983, Classification Physics Abstracts 46.60 78.35 61.12 (*) Equipe de Recherche associee au C.N.R.S. (no 542). Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphys:0198300440103900
TL;DR: It is proposed that brain tubulin microheterogeneity is associated with the presence of neurons and not of glia and may, therefore, play a specific role in maintaining neuronal shape and function.
Abstract: The microheterogeneity of the alpha and beta isoforms of tubulin in brain cells in culture was studied The cells were prepared from two precise regions of the embryonic mouse brain (ED15), the striatum and the mesencephalon It was possible to maintain virtually pure cultures of neuronal or glial cells up to 1 and 4 weeks in vitro, respectively The tubulin heterogeneity of striatal and mesencephalic neurons was found to be very similar after a few days in culture More precise examination of pure neurons from the striatum revealed that their tubulin content after 7 days in vitro exhibited the same degree of complexity as a control extract from a 4 day-old mouse brain In fact, we could detect the presence of at least six alpha and nine beta tubulin isoforms Among these isoforms a specific family of beta proteins (beta' tubulin) and the more acidic alpha proteins were present Since these isoforms have, up to now, been found only in tubulin extracts prepared from the nervous system, our experiments suggest that they belong to the neuronal subpopulation of this tissue This point is reinforced by their complete absence from the tubulin proteins extracted from pure glial cells even after several weeks in vitro These results lead us to propose that brain tubulin microheterogeneity is associated with the presence of neurons and not of glia and may, therefore, play a specific role in maintaining neuronal shape and function
TL;DR: The effects of naloxone on alcohol intake in ethanol naive and dependent rats are interpreted in relation to a general non-specific action of nalanxone on preferred or aversive flavoured solutions.
Abstract: Acute effects of the opiate antagonist, naloxone, on alcohol intake have been examined and compared in naive and behaviorally dependent rats. In naive rats the aversion to an 8% alcohol solution exhibited in a 30 min presentation was selectively augmented by an IP administration of naloxone (1 mg/kg) 30 min before a morning drinking session. In other rats, behavioral dependence was established by 15 days of IG administration of intoxicating doses of alcohol. This dependence was exhibited by a sustained preference for ethanol for 6 days. Naloxone (1 mg/kg) abolishes the acquired preference for ethanol tested during an 8 hour day time presentation. These effects of naloxone on alcohol intake in ethanol naive and dependent rats are interpreted in relation to a general non-specific action of naloxone on preferred or aversive flavoured solutions.
University of Rochester1, Collège de France2, Rutgers University3, University of Oklahoma4, Syracuse University5, Vanderbilt University6, Cornell University7, Lawrence Berkeley National Laboratory8, Massachusetts Institute of Technology9, CERN10, Ithaca College11, Harvard University12, University of Wisconsin-Madison13, Ohio State University14
TL;DR: In this paper, the charged-$B$ mass is 5270.0 MeV and the neutral-$B $ mass was 5274.5 MeV. The charged/$B$-meson decays to final states consisting of a ${D}^{0}$ or ${D]^{*\ifmmode\pm\else\textpm\fi{}}$ and one or two charged pions have been observed.
Abstract: $B$-meson decays to final states consisting of a ${D}^{0}$ or ${D}^{*\ifmmode\pm\else\textpm\fi{}}$ and one or two charged pions have been observed. The charged-$B$ mass is 5270.8 \ifmmode\pm\else\textpm\fi{} 2.3 \ifmmode\pm\else\textpm\fi{} 2.0 MeV and the neutral-$B$ mass is 5274.2 \ifmmode\pm\else\textpm\fi{} 1.9 \ifmmode\pm\else\textpm\fi{} 2.0 MeV.
TL;DR: It is concluded that the short-term stimulation of Na−K-ATPase in the collecting tubule, after an acute administration of aldosterone, may be responsible for the simultaneous increase in sodium transport.
Abstract: The short-term effect of one single injection of aldosterone on the renal sodium transport on one hand, and the Na−K-ATPase activity on the other hand, was studied in chronic adrenalectomized rats. Sodium transport was estimated by clearances, and Na−K-ATPase was measured in microdissected fragments of the nephron, according to our microtechnique previously described. Five to eight days after adrenalectomy, only 30% of the initial enzyme activity was recovered in the cortical collecting tubule (CCT). Administration of aldosterone completely restored the ATP-ase activity within three hours. Adrenalectomy also curtailed by 20–45% the activity of other nephron segments but aldosterone had no stimulatory effect on them. Sodium-reabsorption also increased after the hormone injection, following the same time (0.5