A light and electron microscope study of spherical structures in the test cells of an ascidianCiona intestinalis L.

1984

Spherical structures in the test cells that surround the embryos of the ascidianCiona intestinalis L. (Tunicata, phylum Chordata) were studied by both light and electron microscope. Our data support the view that these structures are microorganism-like cells living in symbiosis with the test cells. Their possible role is discussed.

Evaluation of Hemodynamic Parameters for Adaptive Control of the Artificial Heart by Simulation of the Vascular System

1984

Abstract A nonlinear dynamic mathematical model of the cardiovascular system is outlined, which is employable to analyse the hemodynamic system behaviour under normal as well as under pathological conditions. By modifying this model, assuming that cardiac output is constant at a preset level (which is in accordance with most of the total artificial heart systems, since their pumps output is preselected with fixed driving parameters), the hemodynamic behaviour of a circulation system with an artificial heart was simulated. Comparing the simulation results with those obtained from total artificial heart experiments, a good agreement in right atrial and aortic pressure under exercise condition…

Determination of the total photo-absorption cross section of 197Au from () reaction cross sections

1984

Abstract Cross sections for the reactions 197Au ( γ, ℩ n ) (x ⩽ 12) have been measured for bremsstrahlung end-point energies in the range 60–340 MeV. From these dominant cross sections, the total photon absorption cross section is determined using a cascade-evaporation calculation to account for the missing reaction channels. The enhancement factor for the classical E1 sum rule is found to be 0.93 ± 0.10.

Conformational study of methyl esters of some aliphaticerythro- andthreo-dichlorocarboxylic acids

1984

The average conformations of methyl esters of some aliphatic erythro- and threo-dichlorocarboxylic acids in dilute carbon tetrachloride solutions have been determined from the vicinal proton–proton coupling constants and 1H NMR shifts. The 13C shift differences between the erythro and threo forms are compared and discussed with regard to the differences in the average conformations.

Primary megaureter in adults.

1984

The terminology of megaureters, their histological findings and etiology vary greatly in the literature. Primary obstructed megaureters must be clearly differentiated from megaureters caused by infravesical obstruction. The characterization and therapeutical consequences of the two types also differ. In a retrospective study, 43 adult patients with 54 primary obstructed megaureters (male:female = 30:13) were studied. This diagnosis excluded infravesical obstruction, reflux and neurogenic disorders. The main symptoms were flank pain, infection and hematuria. An operation was performed in 25 patients; 29 were treated conservatively. The criteria for surgery are discussed in relation to sympto…

Immunohistological differential diagnosis of inflammatory colonic diseases.

1984

Immunohistological investigations were carried out on human colonic tissue from, I healthy mucosa, 2 slightly inflamed mucosa, 3 mucosa with ulcerative colitis, 4 mucosa with Crohn's colitis, using antibodies against immunoglobulins and complement components. All our antibodies, including F(ab')2 fragments, demonstrated a progressive increase of labelled cells from healthy mucosa through slightly inflamed mucosa to mucosa with ulcerative colitis, in contrast to a complete absence of labelled cells in cases of Crohn's disease. The results are discussed with regard to their pathogenesis and their clinical significance for the differentiation of ulcerative colitis and Crohn's colitis.

Temporal changes of chromosomal polymorphism in natural populations of Drosophila subobscura

1984

The behaviour of the chromosomal polymorphism of D. subobscura was analyzed in relation to temporal changes, daily, seasonal and annual. Firstly, chromosome analyses were carried out over a year in a natural population. Samples were taken at monthly intervals in Tibidabo, a locality close to Barcelona. In all the months except January, the number of individuals captured was enough to carry out a chromosome analysis of that population. The A, E and O chromosomes showed a great uniformity in the frequencies of gene arrangement over the year. However, significant changes occur in the frequencies of J and U chromosomes. The J1 and U1+2+8 arrangements showed a similar tendency, with two maxima, …

Book Review: Isotopeneffekte bei chemischen Reaktionen. By Alfred V. Willi

1984

Evaluation of advanced silica packings for the separation of biopolymers by high-performance liquid chromatography

1984

Abstract In the separation of proteins and peptides by the various modes of high-performance liquid chromatography, the nature of the substrates requires the use of microparticulate silica packings with bonded ligands of appropriate design. Agglomeration of monodisperse silica hydrosols of defined size distribution into beaded particles provides a useful method of controlling the pore size, the size distribution, the particle porosity and surface area of these packings. The particle porosity is shown to be a major factor governing the packing density and packing stability of the column. For size-exclusion chromatography of proteins, parent silicas of pore size 10 and 100 nm with a narrow po…

The distribution of blood group antigens in rodent epithelia

1984

The pattern of distribution of antigens cross-reacting with antibodies to human blood group antigens A and B and two precursor molecules was examined by immunofluorescence in the epidermis, oral mucosa and forestomach of rats and mice. Staining for blood group antigen A was negative. In all epithelia examined, blood group antigen B was present at the surface of basal and parabasal cells, and the H antigen at the surface of spinous cells. N-acetyllactosamine was present on the cell membranes in the upper spinous and granular cell layers of epidermis and forestomach epithelium and was not expressed in the oral epithelia except for a limited area in the dorsal tongue epithelium. Thus, the expr…

false

1984

Studies in organic mass spectrometry. IV. Electron impact induced fragmentation of 2-substituted 3-(5-isoxazolyl)-4(3H)-quinazolinones of pharmaceuti…

1984

The fragmentation under electron impact of thirteen 2-substituted-3-(5-isoxazolyl)-4(3H)-quinazolinones has been investigated with the aid of metastable ion detection and high resolution measurements. Molecular ions are always abundant and the main primary fragmentation route involves acetonitrile elimination through isoxazole ring opening. The other common processes, particularly those leading to the abundant [R-C8H4N2]+ ion (b or b'), as well as those due to the nature of the 2-substituent are reported and discussed.

false

1984

The synthesis and phase behaviour of azo dye containing liquid crystalline side group copolymers are described. These Copolymers show the same electro-optical effects as low molar mass guest-host systems. Their macroscopic oriented nematic structure can be frozen in below the glass transition temperature resulting in a polymer film with dichroic properties. The behaviour of the copolymers (phase behaviour, surface and electric field orientation) can be improved via mixtures with low molar mass liquid crystals.

Determination of hexacelsian by infrared spectroscopy.

1984

Hexacelsian has been determined by infrared spectroscopy with KBr discs and K(4)Fe(CN)(6) as internal standard. A KBr particle size of40 mum gave better homogenization of the sample-KBr mixture than a particle size in the 40-70 mum range. For determinations of hexacelsian in synthetic samples containing amorphous phase or celsian, calibration curves were constructed. A least-squares fit yielded correlation coefficients of 0.998 and 0.997.

Zwei Muskelrezeptoren an der Mandibel von Leuctra (Insecta, Plecoptera) ? Beispiele f�r nicht-cili�re Sinnesorgane mit Tubulark�rper-�hnlichen Strukt…

1984

Beide Muskelrezeptoren an der Mandibel von Leuctra ziehen vom vorderen Tentorium-Arm zur Mandibel-Basis. Der ventrale Rezeptor besteht aus zwei dunnen Muskelfasern (6 bis 7 μm Durchmesser) und mindestens 10 multiterminalen Sinneszellen, deren Dendriten sich im Innern der Fasern verzweigen und an den Z-Scheiben enden. Der dorsale Rezeptor besitzt drei ahnlich dunne Muskelfasern, aber nur eine einzelne multiterminale Sinneszelle. Ihre Dendriten enden im Ansatzgebiet des Muskels, zwischen Muskelfasern und Epidermiszellen.

Transcription in bacteriophage f1-infected Escherichia coli: RNA synthesized on DNA of deletion mutant PII shows the existence of a two-site terminat…

1984

Two different transcripts are synthesized on the DNA of deletion mutant PII of bacteriophage f1 in E. coli cells infected with this miniphage. Both RNA species appear to be primary transcripts and differ by about 100 nucleotides at their 3'OH end. Mapping of these molecules on the miniphage genome suggests that a two-site terminator is active at the end of the I region of transcription of bacteriophage f1.

A Study of Lipid-Lipid and Lipid-Polypeptide Interactions by High Performance Liquid Chromatography

1984

Abstract Ternary systems containing phosphatidylcholine-cholesterol, phosphatidylcholine-gramicidin A or cholesterol-gramicidin A in tetrahydrofuran have been examined by high performance liquid chromatography. Preferential solvation of cholesterol and especially gramicidin A by phosphatidylcholine is observed. These results are interpreted in terms of hydrophobic interactions between membrane components.

Electrophysiological properties of rat pinealocytes: Evidence for circadian and ultradian rhythms

1984

Extracellular single-unit recordings were made during day- and night-time in the pineal gland of urethane-anesthetized adult male Sprague-Dawley rats. All cells exhibiting spontaneous electrical activity had firing frequencies from less than 1 Hz to about 100 Hz, and their discharge patterns were characterized as regular, irregular or bursting. While most of the spontaneously active cells (n = 163) showed a uniform activity level throughout the recording period (30-120 min), a group of 9 cells exhibited oscillatory rhythms with periods of 4-8 min. In addition, long-term recordings across day- and night-time from five cells revealed increasing activity during night-time in three cells, while…

Les coûts et les dépenses d'enseignement : le cas de la France

1984

référence interne : 84018

PHOSPHORORGANISCHE VERBINDUNGEN 1091DIE SYNTHESE FLUORESZIERENDER REAGENTIEN MIT CHEMOSELEKTIVEN ANKERGRUPPEN

1984

Abstract A route for the synthesis of type B-compounds is reported. Compound 5 is a strong fluorescent and is O-selective. Type C-compounds, for example 10a to 10d show a high fluorescence and are O-selective. They are obtained via 6 and 7 (n=2–4,6; R=Me, X=F). Boc-serine is O-phosphonylated by the methyl-phosphonicacid-esterfluorides, for example 10c. ω-(9-Acridinyl)alkyl-phosphonicacid-alkyl-esterfluorides, like 22, are available in only moderate yields via 15a-e as intermediates. More but unsuccessful experiments for the synthesis of fluorescent and O-selective acridine compounds are reported shortly. Die Synthese von Verbindungen vom Typ B wird beschrieben. Die Verbindung 5 verbindet Fl…

Isolation and structural characterization of polypeptide antibiotics of the peptaibol class by high-performance liquid chromatography with field deso…

1984

Abstract A number of polypeptide antibiotics of the peptaibol class, i.e., trichotoxin, alamethicin, suzukacillin, hypelcin and paracelsin, have been separated into components and isolated by high-performance liquid chromatography on spherical, porous octadecylsilyl bonded phases. All peptaibols were found to reveal a strong microheterogeneity due to single or multiple amino acid exchange. Most of the closely related and partially isobaric sequence analogue could be resolved using mixed alcohol—water eluents. As demonstrated by the structure analysis of the paracelsins and the main component of trichotoxin A-50, high-performance liquid chromatography with field desorption and fast atom bomb…

Observation et évaluation du dispositif de formation et d'insertion des jeunes de 16 à 18 ans en Bourgogne : les entreprises et l'alternance

1984

false

1984

Influence de la structure de chaine sur le type de phase et relation entre la masse moleculaire et les temperatures de transition

Les entreprises et l'alternance en Bourgogne

1984

The inhibitory effect of D-glucosamine on thymidine kinase in chick embryo retinas and HeLa cells

1984

D-Glucosamine markedly inhibits thymidine incorporation into the TCA-insoluble fraction and thymidine kinase activity in HeLa cells. Both the inhibitory effects are also observed in isolated retinas of chick embryos. In this case the inhibitory effects are age-dependent and the magnitude of the responses decreases with embryonic development. In addition the time of exposure to D-glucosamine which is necessary to reveal the inhibitory effect on thymidine kinase increases with the age of the embryos.

Photochemie des 1,3,5‐Tristyrylbenzols

1984

In Abhangigkeit von den Reaktionsbedingungen erhalt man bei der Belichtung der Titelverbindung 1 das Cyclophan 5, das Pyrenderivat 6 oder das polykondensierte aromatische System 9. Fur den neuen Cyclophantyp 5, bei dem zwei Benzolringe selbst wieder durch Ringe verbruckt sind, wurde eine Rontgenstrukturanalyse durchgefuhrt. Photochemistry of 1,3,5-Tristyrylbenzene Depending on the reaction conditions the irradiation of the title compound 1 yields the cyclophane 5, the pyrene derivative 6, or the polycondensed aromatic system 9. An X-ray analysis was performed for 5, representing a new type of cyclophane in which two benzene rings are bridged again by rings.

Double-blind, crossover study of the clinical efficacy and the hemorheological effects of pentoxifylline in patients with occlusive arterial disease …

1984

The effect of a 3 month daily administration of 800 mg pentoxifylline (Trental 400 bds) or placebo was assessed under double blind crossover design in 18 patients (12 males and 6 females) with peripheral occlusive arterial disease in respect of painfree walking distance and various hemorheological and hemostasiological variables, platelet aggregation, serum cholesterol and triglycerides. In first treatment period walking distance significantly increased with pentoxifylline by 46% from baseline 121 ± 15 m and by 4% with placebo from baseline 134 ± 18 m. Pentoxifylline administration furthermore yielded significant decrease in whole blood and plasma viscosity and significant increase in eryt…

Preparation and reactions of 1-methylpyrid-6-one-2-yl compounds of palladium(II) and platinum(II)

1984

Abstract The compounds trans -[MCl{(1-Me)C 5 H 3 (6-O)N- C 2 }(L) 2 ] (M = Pd, Pt; L = PPh 3 , PMe 2 Ph), can be prepared from the reaction of the corresponding 1-methyl-6-chloro-2-pyridylium cationic complexes, trans -[MCl{(1-Me)C 5 H 3 (6-Cl)N- C 2 }(L) 2 ]ClO 4 , with a mixture of acetic acid, ethanol, and triethylamine in the molar ratio M/MeCO 2 H/EtOH/NEt 3 of 1/3/3/4. The rate is slow compared to that of the 1-methyl-2-chloropyridinium cation under similar conditions, and is markedly affected by the steric and electronic effects of the trans -MCl(L) 2 unit. The novel 1-methylpyrid-6-one-2-yl derivatives have been characterized by conventional spectroscopic techniques and by reactions…

Insertion of isocyanides into the 2-one-1-propyl—palladium(II) bond: A convenient synthetic route to C1-palladated 1-amino-3-one-1-butene compounds

1984

Abstract Migratory insertion of isocyanides CNR (R = p -C 6 H 4 OMe, Me) into the palladium—carbon σ bond of trans -[PdCl(CH 2 COMe)(PPh 3 ) 2 ] (I) yields the 1-amino-3-one-1-butenyl complexes trans -[PdCl{C(NHR)CHCOMe}(PPh 3 ) 2 ] (IIa, R = p -C 6 H 4 OMe; IIb, R = Me), which have been characterized by IR, 1 H and 31 P NMR spectra. The reaction of IIa with nickel acetate gives a diamagnetic bischelate complex of the type [Ni(ON) 2 ] , in which the deprotonated 1-amino-3-one-1-butenyl moiety acts as a bidentate O,N ligand.

WEITERE SELEKTIVITÄTSSTUDIEN AM BEISPIEL EINES ARYLSULFONYLACETYLENS

1984

Abstract With 1-(phenylsulfonyl)propyne-(1) 1 as a model compound, we have investigated the competition reactions with RSH, RNH2 and ROH (R=n-Bu). With RSH and RNH2, the cis-trans-isomeric olefins 2 to 5 are formed. ROH does not react under these conditions. The compounds 6 and 7 are obtained only with ROH as the alcoholate. The reactivity of 1 with nucleophiles is increased in comparison to phenylvinyl sulfone; the selectivity of 1 is, however, decreased. The difference in reactivity of 1 and phenylvinyl sulfone corresponds to ca. 10:1. Mit 1-(Phenylsulfonyl)-propin-(1) 1 als Modellverbindung haben wir die konkurrierenden Umsetzungen mit RSH, RNH2 und ROH (R=n-Bu) studiert. Mit RSH und RNH…

Mycorrhizal dependency of several plant species under field conditions in a soil of moderate P. fertility

1984

International audience

Les systèmes de comportement du jeune enfant dans un groupe de pairs, aspects fonctionnels et ontogénétiques

1984

International audience

Studien zum Vorgang der Wasserstoffübertragung, 73. Die Reduktion prochiraler Alkyl(aryl)ketone zu Carbinolen und Pinakolen mit Alkaliamalgamen

1984

Es werden die Faktoren ermittelt, welche die Stereochemie und das Mengenverhaltnis (C/P) des bei der Reduktion von Acetophenon mit Lithium-, Natrium- und Kaliumamalgam (Li/Hg, Na/Hg, K/Hg) gebildeten Carbinols (C) und Pinakols (P) bestimmen. Das C/P-Verhaltnis wird beeinflust a) durch Protonendonatoren, b) durch quartaren Ammoniumsalze, c) durch bis-tertiare Amine. Bei Anwesenheit von optisch aktiven quartaren Ammoniumsalzen und optisch aktiven bis-tertiaren Aminen wird sowohl beim Pinakol als auch beim Carbinol eine geringe optische Induktion beobachtet. Bei der Reduktion von Pivalophenon mit Li/Hg entsteht das anomale Dimerisierungsprodukt 20. Studies on the Occurrence of Hydrogen Transfe…

Offre d'équipements socio-culturels et sportifs et comportement des élèves

1984

International audience

BASE-SPECIFIC RIBONUCLEASES POTENTIALLY INVOLVED IN HETEROGENEOUS NUCLEAR-RNA PROCESSING AND POLY(A) METABOLISM

1984

Abstract Polyadenylation and splicing of heterogeneous nuclear RNA, two crucial steps in mRNA processing, are apparently enzymically mediated processes. This contribution summarizes the properties and the presumed functions of the known poly(A) catabolic enzymes (endoribonuclease IV and V, 2′,3′-exoribonuclease) as well as those of the pyrimidine-specific endoribonucleases associated with snRNP—hnRNP complexes (endoribonuclease VII, acidic p I 4.1 endoribonuclease and poly(U)-specific U1 snRNP-nuclease).

Sister-chromatid exchange in cultured lymphocytes of ewes and their newborn lambs

1984

The incidence of sister-chromatid exchange (SCE) in cultured lymphocytes of ewes and their newborn lambs was determined using the BrdU-Giemsa technique. In all ewe-lamb pairs, the SCE rate in the lambs was less than that of the ewes. The mean SCE frequencies per chromosome of the ewes after lambing and of the newborn lambs were 0.1909 and 0.1581, respectively. The statistical analysis shows that a significant difference exists between SCE in the adult female sheep and their lambs. At the same time, a negative correlation was observed between SCE rate and cell proliferation. The results of this study are compared with those of previous reports on age-dependency of SCE.