Present state of the MAMI control system

1990

Abstract MAMI (Mainz Microtron) is an electron accelerator consisting of a cascade of three race-track microtrons, with an output electron beam of 855 MeV and 100 μA cw [1]. The first two stages (output energy 180 MeV) were operative for nuclear-physics experiments from 1983 to 1987 and have since been transferred to a new building. They will serve as an injector for the third stage, now under construction. The control system for MAMI was based on a versatile process communication software system for a network of processors with multiprocess operating systems. This system has previously proved very successful, so we decided to rely on it as control system for the new, upgraded accelerator, …

Pancuronium improves the neuromuscular transmission defect of human organophosphate intoxication.

1990

Two patients with acute severe organophosphate intoxication showed (1) single evoked compound muscle action potentials (CMAP) with repetitive discharges and (2) prominent decremental responses of CMAP with 20 and 50 Hz supramaximal nerve stimulation. Following the intravenous injection of single small doses of pancuronium, marked improvement in these abnormalities occurred and persisted for several hours. We postulate that the physiologic improvement following low-dose pancuronium results from blockade of acetylcholine receptors, especially those located on the terminal axon responsible for antidromic backfiring.

Calix[4]arenes bridged at the lower rim

1990

Calix[41 arenes, in which two opposite p-positions are linked by an aliphatic chain, and their derivatives show transport or complexation properties strongly dependent on the length of this chain. Bicyclo-calix[4]arenes, a special case of 1,3-bridged calix[41 arenes, and annelated calix[41 arenes, a special case of 1 ,&bridged calix [4] arenes, are also described. Although the preferred conformation of calix[4]arenes is the coneconformation due to its stabilization by a cyclic array of hydrogen bonds between the phenolic hydroxyl goups, these molecules are flexible, with a cone to cone inversion rate of about 150 8-1 for a calix[glarene at 47OC (ref. 1). The cone (or any other) conformation…

An ?-Adrenoceptor Facilitating the Stimulation-Evoked Acetylcholine Release in the Rat Perfused Heart

1990

Mechanical relaxation in miscible polymer systems: the glass transition regime in poly(vinylmethylether) (PVME)-cross-polystyrene (PS) semi-interpene…

1990

Abstract Miscible semi-interpenetrating polymer networks (semi-IPN) of varying composition are prepared by crosslinking polystyrene containing few maleic anhydride groups with a diamine in the presence of linear poly(vinylmethylether) (PVME). The resulting PVME-c-P(ScoMA) semi-IPNs are characterized by their thermal and thermomechanical behaviour. Comparison with the corresponding uncrosslinked material proves that weak crosslinking has a negligible effect on the location of the glass transition as measured by d.s.c. Both the Tg data and the temperatures of the loss modulus maximum E″ (at 1 rad/s) show the same non-linear curved composition dependence. Contrary to this the tan δ maximum var…

Rat liver endothelial and Kupffer cell-mediated mutagenicity of polycyclic aromatic hydrocarbons and aflatoxin B1.

1990

The ability of isolated rat liver endothelial and Kupffer cells to activate benzo(a)pyrene (BP), trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene (DDBP), trans-1,2-dihydroxy-1,2-dihydrochrysene (DDCH), and aflatoxin B1 (AFB1) to mutagenic metabolites was assessed by means of a cell-mediated bacterial mutagenicity assay and compared with the ability of parenchymal cells to activate these compounds. Endothelial and Kupffer cells from untreated rats were able to activate AFB1 and DDBP; DDBP was activated even in the absence of an NADPH-generating system. Pretreating the animals with Aroclor 1254 strongly enhanced the mutagenicity of the dihydrodiol, whereas the mutagenicity of AFB1 showed a sligh…

Study on the histamine-like activity of guanfacine

1990

Abstract The effects of guanfacine have been studied on guinea-pig isolated atria and diethylstilboestrol-treated rat isolated uterus to determine whether it possesses histamine-like activity. Guanfacine produced a concentration-dependent negative chronotropic effect which was not modified by ranitidine (0.1 μM). In rat isolated uterus contracted by KCl, clonidine (5–5000 μM) produced concentration-dependent relaxation which was blocked by ranitidine (0.1 μM), but guanfacine only produced relaxation at high concentrations (100–1000 μM), and this was not affected by ranitidine (0.1 μM). It is concluded that guanfacine, unlike clonidine, does not produce effects due to activation of H2-recept…

6-Phosphofructokinase from frog skeletal muscle: purification and properties

1990

The electromigration and diffusion of hydrogen in molybdenum

1990

Abstract The electromigration and diffusion of hydrogen atoms in molybdenum were investigated using the resistance method in the temperature range 293–773 K. The following dependence of the diffusion coefficient D and electrical mobility vE on temperature were obtained: D = (5.3 ± 1.53) × 10 −10 exp {− (0.8 ± 0.01) eV kT } { m 2 s −1 } v E = (1.24 ± 0.19) × 10 −8 exp {− (0.9 ± 0.01) eV kT }{ m 2 ( V s ) −1 } . The hydrogen migrates towards the cathode and the effective valency grows with temperature, fulfilling the relation Z eff = (1.42 ± 0.03) − (5.0 ± 0.2) × 10 −8 (Ω m ) ρ ; where ρ is the specific electric resistance.

Antibacterial polypeptides of Lactobacillus species

1990

Twelve of 79 strains of the genus Lactobacillus, mainly isolated from plants or fermenting material, were found to inhibit at least one of the nine indicator strains of the species Lact. brevis, Pediococcus damnosus and Leucanostoc oenos. The antimicrobial activities from Lact. brevis B 37 and Lact. casei B 80 were caused by polypeptides detectable in the culture liquids. They are bacteriocins with a narrow antimicrobial spectrum. Brevicin 37 from Lact. brevis B 37 was active against many lactic acid bacteria and Nocardia corallina, whereas caseicin 80 from Lact. casei B 80 inhibits only one other strain of Lact. casei. Brevicin 37 is stable at 121dC, caseicin 80 is inactivated above 60dC, …

Alternative sites for ecdysteroid production in insects

1990

Summary Several evidences have been obtained in various insect species demonstrating that, besides prothoracic glands and ovaries, other tissues could be alternative sites of moulting hormone production. After a detailed review on the various methods of investigation and criteria required to validate such observations, the nature of these sites, namely oenocytes, epidermis and testes, is discussed. Their possible involvement in moulting and/or reproduction is analyzed, giving the opportunity to put forward several new hypotheses. In particular, autocrine and paracrine secretions of ecdysteroids could play a role in localized developmental events, more difficult to control from endocrine gla…

Growth control in mammalian cells by cell-cell contacts.

1990

Growth of normal diploid mammalian cells in vitro is strongly regulated by the actual cell density. Cell-cell contacts via specific plasma membrane glycoproteins whose glycan moieties interact with specific receptors has been found to be a main growth regulatory principle. Malignant growth is suggested to result from impaired function of these receptors.

Lysosomal trafficking in rat cardiac myocytes.

1990

By immunolabeling of cryosections, we have characterized in rat cardiac myocytes the cation-independent mannose-6-phosphate receptor (MPR), a lysosomal membrane glycoprotein, lgp120, and a lysosomal enzyme, MEP (homologous to cathepsin L). Most of the MPR label was located in large membrane-filled structures (MPR structures) in large clusters of mitochondria adjacent to but distinct from the Golgi complex. Lpg120 and MEP showed typical lysosomal localization throughout the cell, often associated with regions that appeared to contain autophagosome-like structures. In addition, MEP and lgp120 co-localized within MPR structures. MEP and MPR were localized inside the lumen of MPR structures. M…

Star representations of E(2)

1990

We give a complete and explicit realization of the unitary irreducible representations of the universal covering group G of E(2), the Euclidean group in two dimensions, by deformation of the algebra of functions on the dual g* of the Lie algebra of G. We define an adapted Fourier transform for G which gives a natural description of the harmonic analysis of G.

L'evaluation economique du cout et du traitement de la pneumocystose

1990

Photophysical behavior of norharmane related to proximity effect

1990

Abstract Solvent and temperature effects of fluorescence and its polarization characteristics for norharmane were studied. From the results obtained it is concluded that the fluorescent state changes from the φφ ∗ -type in a polar solvent (EPA) to nφ ∗ -type in a nonpolar solvent (MC), and also that lowest singlet excited states (φφ ∗ -type and nφ ∗ -type) interact by vibronic coupling. In the nonpolar solvent (MC) the lowest singlet excited states are very close in energy and consequently the vibronic coupling is stronger. At high temperatures, in a nonpolar solvent (MC), the emission is from both the φφ ∗ - and nφ ∗ -states due to thermal equilibration, while at low temperatures the emiss…

Liquid crystal polymers from swallow-tailed mesogens

1990

Abstract Swallow-tailed compounds containing an acetylenic unit have been synthesized. Only those compounds with a three ring structure exhibited liquid-crystalline phases. The platinum catalysed addition of these monomers to compounds containing Si-H groups was used to synthesize polymeric materials. Only those polymers with the tetramethyldisiloxane unit showed mesophases. The synthesis, characterization, and phase behaviour are described.

Two-dimensional electrical ordering in physisorbed monolayers

1990

Abstract Monolayers of polar molecules CF3H, CF3Cl and CF2Cl2 have been physisorbed on the graphite (001) surface and studied by X-ray diffraction and dielectric measurements. The temperature-coverage phase diagrams of the quasitwodimensional crystalline phases are presented. The structures of the paraelectric and the electrically ordered phases have been determined. The phase transitions are discussed.

Establishment of different T cell sublines using either interleukin 2 or interleukin 4 as growth factors

1990

Purified protein derivative reactive T cell lines were established under identical conditions with the exception that different lymphokines, namely interleukin (IL) 2 and IL 4 were employed as growth factors. IL 2 favored the development of T cell lines (LNC.2) which upon activation by concanavalin A (Con A) secreted predominantly lymphokines characteristic of TH1 cells. By contrast, T cell lines established with the aid of IL 4 as growth factor (LNC.4) produced mainly lymphokines representative of TH2 cells. Apart from their pattern of lymphokine secretion LNC.2 and LNC.4 T cells were found to differ in their proliferative response to lymphokines and Con A. LNC.2 T cells proliferated only …

Competition for nest-boxes among four vertebrate species: an experimental study in orange groves

1990

The experiment was carried out in eastern Spain from 1986 to 1988. The nest-boxes were placed at the height where natural holes occur, visited twice a week, and cleaned after every breeding season. Four vertebrate species used the nest-boxes: great tit Parus major, house sparrow Passer domesticus, tree sparrow Passer montanus, and black rat Rattus rattus. The first species to occupy the nest-boxes, the great tit, was the least able to defend them. During the third year breeding by the great tit in the nest-boxes decreased markedly, probably due to the increase of house sparrow and black rat occupation. We suggest that differences among species in their ability to discover and use new holes …

Synthesis and phase behaviour of liquid-crystalline side group polyesters

1990

Abstract Several series of liquid-crystalline side group polymers with a polyester backbone structure have been synthesized using mesogenic diethylmalonate and 1,3-propanediol derivatives. The structures of the polymer backbone and the mesogenic units have been varied systematically. As shown by differential scanning calorimetry, polarizing microscopy and X-ray diffraction, the side group polyesters exhibit nematic and/or smectic mesophases. Polyesters synthesized from mesogenic diethylmalonate derivatives can tolerate long non-mesogenic segments in the polymer main chain without losing their liquid crystal properties. X-ray studies suggest that some of the smectic polymers exhibit interdig…

Staphylococcus aureus alpha-toxin attack on human platelets promotes assembly of the prothrombinase complex.

1990

alpha-Toxin, the major cytolysin of Staphylococcus aureus, promotes blood coagulation by its attack on human platelets (Bhakdi S., Muhly, M., Mannhardt, U., Hugo, F., Klapettek, K., Mueller-Eckhardt, C., and Roka, L. (1988) J. Exp. Med. 168, 527-542). In the present study we demonstrate that toxin attack on gel-filtered human platelets initiates the assembly of prothrombinase complexes at rates up to 10-fold of controls. Treatment of platelets with 0.1 microgram/ml alpha-toxin resulted in generation of 1.4 units of thrombin/10(8) platelets. A similar rate of thrombin generation was noted when platelets were subjected to three cycles of freezing and thawing. However, the alpha-toxin-induced …

Single cell transplantation reveals interspecific cell communication in Drosophila chimeras

1990

Abstract Cell –cell communication is not only a common strategy for cell fate specification in vertebrates, but plays important roles in invertebrate development as well. We report here on experiments testing the compatibility of mechanisms specifying cell fate among six different Drosophila species. Following interspecific transplantation, the development of single ectodermal cells was traced in order to test their abilities to proliferate and differentiate in a heterologous environment. Despite considerable differences in cell size and length of cell cycle among some of the species, the transplants gave rise to fully differentiated clones that were integrated into the host tissue. Clones …

Analysis of radiolucent gallstones by computed tomography for in vivo estimation of stone components.

1990

. Successful oral litholytic and other non-operative therapies of gallstones require exact determination of the stone components. Since computed tomography (CT) provides highly sensitive measurement of density, we performed a study to evaluate whether CT measurement of stone density allows a prediction of the composition of radiolucent gallstones. Twenty-eight patients presenting with 29 radiolucent gallbladder (n= 17) or common bile duct stones (n=12) were included. Prior to operative or endo-scopic therapy the attenuation values (Hounsfield Units, HU) were assessed in vivo by CT under standardized conditions (Somatom II, 125 KV, 130 mAs). After surgical or endoscopic stone removal the con…

Evidence that adenosine is not involved in the non-adrenergic non-cholinergic relaxation in the rat duodenum.

1990

In rat isolated duodenal segments, adenosine induced, in the presence of atropine and guanethidine, a dose-dependent, long-lasting (about 20 s), tetrodotoxin (TTX)-resistant relaxation both in endoluminal pressure and in isometric tension. Electrical field stimulation (EFS) induced, in the presence of atropine and guanethidine, a TTX-sensitive short-lasting (about 6 s) relaxation followed by a sustained rebound contraction. Theophylline, a P1 receptor antagonist, at the concentration of 100 microM caused a marked inhibition of the adenosine-induced relaxation, while the EFS-induced relaxation was not modified. Our results suggest that adenosine induces relaxation of the rat duodenal smooth …

Studies of the expression of the cytochrome P450IA, P450IIB, and P450IIC gene family in extrahepatic and hepatic tissues.

1990

We have studied the expression of three P-450 gene subfamilies in hepatic and extrahepatic tissues using the sensitive RNAse A protection assay. Members of the P450IA subfamily, which encodes the major methylcholanthrene-inducible cytochromes P-450, were found to be not expressed in extrahepatic tissues of untreated animals, raising the question whether these P-450 play a role in the metabolism of carcinogens in unexposed individuals. In contrast, members of the P450IIB family, some of which encode the major phenobarbital-inducible cytochromes P-450, were found to be expressed in some extrahepatic tissues of untreated rats and here most notably in the lung and in sebaceous glands. Members o…

Electron microscopic immunogold cytochemistry reveals chromogranin A confined to secretory granules of porcine Merkel cells

1990

By ultrastructural immunohistochemistry using the immunogold technique, immunoreactive (ir) Chromogranin A (CGA) was found to be confined to the secretory vesicles of porcine Merkel cells. CGA was present predominantly in the periphery of the electron-dense core and on the clear halo. These findings indicate that CGA is a regular constituent of Merkel cell secretory granules but probably not exclusively responsible for their electron opacity.

Role of Levinson’s theorem in neutron-deuteron quartetS-wave scattering

1990

The real part of the phase shift for elastic neutron-deuteron scattering in the quartet {ital S} wave channel, as calculated with the exact three-body theory, assumes at threshold the value {pi} if normalized to zero at infinity; that is, it does not comply with the expectations raised by a naive application of Levinson's theorem since no bound state exists in this channel. A description of this situation on an equivalent two-body level via a potential, constructed by means of the Marchenko inverse scattering theory, necessitates the introduction of a fictitious bound state. This predominantly attractive, equivalent local potential can be related via supersymmetry to a strictly phase equiva…

Sulfotransferase-mediated chlorination of 1-hydroxymethylpyrene to a mutagen capable of penetrating indicator cells.

1990

Methylated polycyclic aromatic hydrocarbons are common in the human environment. Many of them are stronger carcinogens than their purely aromatic congeners. They may be metabolized to benzylic alcohols. We report here on biochemical and toxicological characteristics of 1-hydroxymethylpyrene (HMP), a typical representative of this class of compounds. Rat liver cytosol, fortified with 3'-phosphoadenosine-5'-phosphosulfate, converted HMP into its sulfate ester (HMPS), HMPS bound covalently to isolated DNA. In physiological buffer at 37 degrees C, HMPS had a half-life of 2 min, the major decomposition product being HMP. Thus, cyclic activation is possible. When Cl- anions were present at physio…

Kinematics of the patellofemoral joint. Investigations on a computer model with reference to patellar fractures.

1990

Patellofemoral kinematics were studied on a computer model. The articulating point of the patella moves from distal to proximal during flexion, until the quadriceps tendon starts to turn around the femur tendo-femoral gliding. The pattern of patellofemoral movement consists of a gliding and rolling component, the latter at its maximum at the beginning of flexion. The pathway of the instant centers of motion moves from dorsal to ventral during flexion. Stress analysis shows that the contact area is at all times the area of maximum bending stress. The distal part of the patella is the part with mechanical stress at all angles of flexion. The conclusions to be drawn for treatment are that frac…

Caseicin 80: purification and characterization of a new bacteriocin from Lactobacillus casei

1990

When grown in complex or synthetic media, Lactobacillus casei B 80 synthesizes a mitomycin C-inducible polypeptide with very specific bactericidal activity against the sensitive strain Lactobacillus casei B 109. The amount of secreted bacteriocin in the culture solution was low, about 1 mg/l. The bacteriocin which we called caseicin 80, was also detectable in cell extracts, although only 2% of the total activity was retained intracellularly. Caseicin 80 was concentrated by ultrafiltration and purified by cation exchange chromatography with Cellulose SE-23 and Superose. The molecular weight was in the range of M r=40,000–42,000 and the isoelectric point was pH 4.5.

Application of small angle neutron scattering to micellar fluids

1990

Abstract In this paper we present a short overview of the application of small angle neutron scattering (SANS) to micellar fluids. In the first part of the paper a general expression of the scattering equation is derived, with particular emphasis on the approximations involved and on their practical consequences. In the second part of the paper we present six selected test cases (such as mono- and polydisperse fluids, critical fluids, shapes other than spherical, etc.) taken from our own work, to demonstrate the kind of analysis performed in each case to extract the information from SANS data.

Stereoselective metabolism of dibenz(a,h)anthracene to trans-dihydrodiols and their activation to bacterial mutagens.

1990

Dibenz(a,h)anthracene (DBA), a carcinogenic, polycyclic aromatic hydrocarbon ubiquitous in the environment, is metabolized by the hepatic microsomal fraction of immature Sprague-Dawley rats pretreated with Aroclor 1254 to 27 ethyl acetate-extractable metabolites. More than half of these metabolites (51%) consisted of trans-1,2-; -3,4-; and -5,6-dihydrodiols including their identified secondary metabolites. The three trans-dihydrodiols (4.9, 15.8, and 0.6% of total metabolic conversion) were highly enriched in their R,R enantiomers (85, 71, and 98%) as determined by high performance liquid chromatography on suitable chiral stationary phases. This is explained on the basis of the stereoselect…

Eukaryotic tRNAs(Pro): primary structure of the anticodon loop; presence of 5-carbamoylmethyluridine or inosine as the first nucleoside of the antico…

1990

The modified nucleoside U*, located in the first position of the anticodon of yeast, chicken liver and bovine liver tRNA(Pro) (anticodon U*GG), has been determined by means of TLC, HPLC, ultraviolet spectrum and gas chromatography-mass spectrometry. The structure was established as 5-carbamoylmethyluridine (ncm5U). In addition, we report on the primary structures of the above-mentioned tRNAs as well as those which have the IGG anticodon. In yeast, the two tRNA(Pro) (anticodons U*GG and IGG) differ by eight nucleotides, whereas in chicken and in bovine liver, both anticodons are carried by the same 'body tRNA' with one posttranscriptional exception at position 32, where pseudouridine is asso…

Senile cataract: a review on free radical related pathogenesis and antioxidant prevention

1990

Abstract Glutathione metabolism plays an essential role in the homeostasis of the lens. Thus, it is not surprising that experimental depletion of this substance leads to a process of lens disorganization similar to senile cataract and that in all types of irreversible cataract there is a decrease in the glutathione content of the lens. Therefore, it may be useful in preventive geriatrics to raise the glutathione concentration of the lens and, since glutathione monoethyl ester can cross the capsule and membranes of the lens, administration of this compound may be the treatment of choice. This could be complemented by long-term administration of small doses of acetylsalicylic acid, in the ear…

ChemInform Abstract: First Electrophilic Substitutions of 3-Substituted Indoles with Diethoxycarbenium Tetrafluoroborate: Functionalized Indole Deriv…

1990

The indoles 2a-2c react with diethoxycarbenium tetrafluoroborate (1) to furnish the indolecarbaldehydes 3a-3d. In the thermodynamically controlled reaction of 3-methylindole (2a) with 1 the tris(indolyl)methane 4 and diskatole (5), are formed in addition. The limitations of these reactions are discussed and evidence is presented for a C-3-ipso-attack and a Wagner-Meerwein rearrangement, respectively, leading to the formation of 3b or 3d. Erste elektrophile Substitution von 3-substituierten Indolen mit Diethoxycarbenium-Tetrafluoroborat: Funktionalisierte Indol-Derivate Die Indole 2a-2c reagieren mit dem per se synthetisierten Diethoxycarbenium-Tetrafluoroborat (1) zu den Indolcarbaldehyden …