Bleomycin inhibition of DNA synthesis in isolated enzyme systems and in intact cell systems.

1975

Abstract Blcomycin (BLM) inhibits DNA and RNA synthesis in different isolated enzyme systems. The inhibition effect can be reduced by adcling RNA to the reaction mixture. The activity of the RNA dependent DNA polymerase and of a cell-free protein synthesizing system is not affected by BLM. The antibiotic reduces cell proliferation (L5178y mouse lymphoma cells) in vitro at low concentrations by cytostatis and at higher concentrations by cytotoxicity. In BLM-treated L5178y cells DNA synthesis is strongly reduced, while RNA and protein synthesis are not affected. In vivo , using growing quail oviducts, cell proliferation and cytodifferentiation are markedly inhibited after BLM treatment. This …

Comparison of neutron and X-ray scattering of dilute myoglobin solutions.

1975

Experimental results obtained by neutron scattering of dilute solutions of myoglobin are compared with those obtained by X-ray scattering. X-ray scattering remains the more powerful technique at wider angles above 0.3 A−1, where neutron experiments are less accurate because of low coherent scattering probability and high incoherent background. Neutron scattering is preferable at momentum transfers below 0.2 A−1; the conditions for applying the contrast variation method for the evaluation of the three basic scattering functions, which are due to shape and internal structure, equation (3), are ideally fulfilled in this region. Furthermore, neutrons allow observation of the hydrogen-deuterium …

Rhythmische Änderungen der Reaktion auf verschiedene olfaktorische Reize beim Krallenfrosch (Xenopus laevis)

1975

The behavioural response ofXenopus laevis to olfactory cues shows different rhythmical oscillations which do not depend on the chemical nature and the concentration of the stimulus itself. Habituation to such cues occurs very slowly, pointing to their special importance in the feeding behaviour of this species.

Influence of Light on the Bioelectric Potential of the Bean (Phaseolus vulgaris) Hypocotyl Hook

1975

By use of surface electrodes electropotenlial measurements were carried out on hypocotyl hooks of Phaseolus vulgaris seedlings. The hooks were illuminated with a small spot of white, blue, red or far red light. The potential changes in bean hypocotyl hooks do not show the red-far red reversible characteristics of phytochrome-mediated processes. By experimenting with inhibitors of photosynthesis we could demonstrate that the light-triggered potential changes in green bean hooks are correlated to photosynthetic electron transport phenomena. The red-light-induced transient is a depolarization, whereas blue light induces a hyperpolarization. Etiolated beans exhibit no bioelectric potential chan…

The role of dislocations in the solid-state polymerization of monomers having conjugated triple bonds: A study of 2,4-hexadiyne-1,6-diol bis(p-toluen…

1975

The crystal structure of the monomer bis(p-toluene sulfonate) ester of 2,4-hexadiyne-1,6-diol (pT) is conducive from the viewpoint of both the separation distances and molecular configuration, to polymerization, irrespective of whether initiation is thermal, photochemical, or mechanical. The dislocations present in the monomer and polymer structures have been characterized by employing optical microscopic techniques. The slip system (102)[010] is found to be present in both monomer and polymer crystals but the (010)[001] system is found only in the monomer. On this basis a crystal structure for the monomer is proposed based on existing crystallographic information relating to the structure …

Polyreactions in oriented systems, VIII.. Polymerization of a liquid crystalline monomer under the influence of a high magnetic field

1975

Nicethamid‐Analoge, VII. Darstellung eines nicethamid‐analogen Pyrrolo [3,4‐ b ]‐ und Pyrrolo [3,4‐ c ]pyridinons

1975

Die Synthese der potentiell analeptisch wirksamen cyclischen Nicethamid-Analoga 6-Athyl-6,7-dihydro-5H-pyrrolo[3,4-b]pyridin-5-on (9a) und 2-Athyl-2,3-dihydro-1H-pyrrolo[3,4-c]pyridin-3-on (9b) sowie der entsprechenden ringoffenen Verbindungen N-Athyl-2-methylnicotinamid (12a) and N-Athyl-4-methylnicotinamid (12b) wird beschrieben. Nicethamide-Analogues, VII. Synthesis of a Pyrrolo[3,4-b]- and Pyrrolo [3,4-c]pyridinone as Nicethamide Analogues The synthesis of the potentially analeptically active cyclic nicethamide analogues, 6-ethyl-6,7-dihydro-5H-pyrrolo[3,4-b]pyridin-5-one(9a) and 2-ethyl-2,3-dihydro-1H-pyrrolo[3,4-c]pyridin-3-one (9b) as well as the corresponding open-ring compounds N-e…

Activities of Two Peptidases in Resting and Germinating Seeds of Scots Pine, Pinus sylvestris

1975

Extracts prepared from resting seeds of Scots pine, Pinus sylvestris L., rapidly hydrolysed two peptides, Leu–Tyr and Ala–Gly, at pH 8.6 and 7.8, respectively. In gel chromatography on Sephadex G-100 the two activities were eluted as separate peaks, which indicates that they are due to two different peptidases. The seeds were allowed to germinate at 20°C, the activities of the two enzymes were assayed separately on extracts from the endosperm and seedling tissues at different stages of germination, and compared with corresponding changes in dry weight and total nitrogen. Both enzyme activities were relatively high in the endosperm of resting seeds, and they increased about 2- and 3-fold dur…

Vereinfachte Rekursionen zur Richardson-Extrapolation in Spezialf�llen

1975

Recursions are given for Richardson-extrapolation based on generalized asymptotic expansions for the solution of a finite algorithm depending upon a parameterh>0. In particular, these expansions may contain terms likeh ?·log(h), (?>0). Simplified formulae are established in special cases. They are applicable to numerical integration of functions with algebraic or logarithmic endpoint singularities and provide a Romberg-type quadrature.

Les exclus du système français de bourses

1975

International audience

Signal Characteristics of EMG with Special Reference to Reproducibility of Measurements

1975

Reliability and constancy of recordings of EMG signal characteristics were investigated from the measurements taken with miniature size surface electrodes during submaximal and maximal contraction of the rectus femoris muscle. The following EMG variables were studied: integrated EMG (IEMG) various bandwidths of the power spectral density function, mean power frequency (MPF), and rise time, amplitude and number of spikes of the averaged motor unit potential (AMUP). The results indicated that for most of the variables studied the reproducibility of measurements was better within the test session (reliability) than between the different test days (constancy). The reliability values for IEMG, M…

Influence of molecular weight of DNA on the determination of anti-DNA antibodies in systemic lupus erythematosus (SLE) sera by radioimmunoassay

1975

Using a radioimmunoassay (RIA) based on the Farr technique with radioactively labeled 3-H-DNA for quantitative measurements of anti-DNA antibodies in sera of patients with systemic lupus erythematosus (SLE), the influence of molecular weight of DNA (ranging from 0.1 times 10-6 to 22.0 times 10-6 daltons) on binding and precipitation in this system has been investigated. Comparing our results with mathematical models it follows that one antibody molecule is fixed on the average to a statistical DNA segment of 2 times 10-6 to 4 times 10-6 daltons. Furthermore binding capacity of the DNA was found to be independent of the molecular weight, as demonstrated in a double label experiment using 14-…

The behaviour of 2-nitrothiophene and of 3-nitrothiophene with some nucleophiles

1975

The reactivity of 2-nitrothiophene (1) and of 3-nitrothiophene (II) with some nucleophiles has been studied. According to calculated electronic densities I can receive nucleophilic attack at C3 and C5 depending on the nucleophile used, but II only at C2. With N-lithium piperidine both I and II also give coupling products (VII and XI respectively) of the hithienyl type.

Rôle du flux thermique à l'interface dans l'interprétation de l'effet Smith Topley

1975

International audience

Effective-Lagrangian formulation of generalized vector dominance. II

1975

As in a preceding paper we generalize the Lagrangian of Lee and Zumino to include several mutually interacting vector mesons. The treatment is more general in the sense that all possible interactions between the vector mesons, compatible with the field-current proportionality relations, are now discussed. It is moreover demonstrated that also the fields corresponding to the physical vector mesons satisfy a field-current proportionality relation of exactly the same form. Comparison of the different schemes and their implications for the magnetic moments of the vector mesons are discussed.

Nuclear Magnetic Moments ofBi205,207,209Isotopes—Hyperfine Structure of the 15-dayBi2053067-Å Line

1975

ChemInform Abstract: COMPLEXES OF ORGANOMETALLIC COMPOUNDS PART 42, SPECTROSCOPIC STUDIES OF N,N′-ETHYLENEBIS(ACETYLACETONEIMINE) AND N,N′-ETHYLENEBI…

1975

Abstract The nature of the 1 1 adducts formed from the ligands N,N′-ethylenebis(acetylacetonemine) and N,N′-ethylenebis(salicylideneimine) with Ph2PbCl2 and PhTlCl2 was investigated in the solid state and in methanol solution by IR, electronic and PMR spectroscopy, and by osmometry and conductivity. The adducts exist only in the solid state and dissociate fully into the parent compounds in solution. Polymeric structures are proposed for the solids, in which bis-monodentate ligands bridge the organometallic moieties.

Muonic Isotope Shifts in the Even Fe Nuclei

1975

Einige Bemerkungen zu den regionalstatistischen Einheiten der Europäischen Gemeinschaften

1975

Cross-sections for the (γ, n) reaction in9Be,12C and16O at 60 MeV photon energy

1975

Gelchromatographie, 12. Gelchromatographisches Verhalten von Polyvinylalkoholgelen

1975

Durch Hydrolyse von Copolymeren aus Vinylacetat und 1,4-Bis(vinyloxy)butan werden vernetzte Polyvinylalkoholgele hergestellt und ihre Eignung als hydrophile stationare Phase bei gelchromatographischen Trennungen mit Dextranen, Poly(athylenoxid)en und Proteinen als Testsubstanzen gepruft. Die Gele sind druck- und biostabil und zeigen keine storende Adsorption. Je nach Herstellungsbedingungen werden Ausschlusmolekulargewichte bis zu 106 erzielt. Hydrolysis of copolymers from vinyl acetate and 1,4-bis(vinyloxy)butane results in crosslinked poly(vinyl alcohol) gels. Their applicability as hydrophilic stationary phase in gel permeation chromatography is investigated using dextranes, poly(ethylen…

The biological activity of bacteriophage DNA, prepared by the cationic detergent dilution technique

1975

Abstract The preparation of phage lambda DNA infecting E. coli K 12 with cationic detergent is described. This DNA infects E. coli spheroblasts with the same efficiency as DNA prepared by phenol methods.

Ein schnelles on-line trennsystem unter anwendung von helium-jet- und zentrifugentechnik

1975

Abstract A centrifuge for continuous liquid-liquid phase separation is described. It is designed for rapid solvent extraction of short-lived radioactive isotopes (half-lives in the order of seconds). The centrifuge is characterized by simple construction and operation principle, easy handling, low cost, and a minimum hold-up time of less than five seconds (phase purity 99.0–99.9%). The on-line connection to a helium-jet transport system is described. Problems concerning the transfer of activities into a liquid phase from the helium-jet at atmospheric pressure are discussed.

Heavy-metal and or?anic-carbon content of recent sediments near mainz

1975

Inhibition by oxotremorine of acetylcholine resting release from guinea pig-ileum longitudinal muscle strips

1975

1. Longitudinal muscle strips of the guinea-pig ileum were incubated in Tyrode solution containing either DFP or physostigmine as cholinesterase inhibior. After a 90 min preincubation period the acetylcholine resting release into the medium was determined. Acetylcholine was estimated by gas chromatography. 2. The resting release was 0.39 nmol/g×min irrespective of the cholinesterase inhibitor used. In the presence of hexamethonium, or after omission of external calcium, the resting release fell by 50 and 55%, respectively. 3. Oxotremorine (10−5 and 10−4 M) significantly inhibited the resting release of acetylcholine by 25 and 33%, respectively. The inhibitory effect of oxotremorine was comp…

Spin and magnetic moment of25Na by ?-radiation detected optical pumping

1975

25Na (T1/2 = 60 sec) has been produced in a22Ne target by the (α,p) reaction and polarized by means of spin-exchange scattering with optically pumped87Rb. The asymmetry in the β decay of polarized nuclei served to detect rf transitions between hfs Zeeman levels of the atomic ground state, yielding spinI = 5/2 and hyperfine splitting ΔW= 2648.5(3.0) MHz, from which the magnetic moment μI = 3.683(4)nm (corrected for diamagnetism) was deduced.

Anomalies in the temperature dependence of the 1.2-? absorption of liquid water

1975

The weakly absorbed 1.2-μ combination band of water was accurately studied as a function of temperature, in both its profile and first derivative, to obtain information on the bulk properties of liquid water. Arrhenius plots of integrated component intensity ratios showed well aligned experimental points, except for a neatly defined break occurring in the 30 to 40°C temperature interval for pure water A similar break, shifted by some 18°C towards lower temperature, was found in the case of 1M NaClO4 aqueous solutions. The breaks are tentatively assumed to result from abrupt though subtle changes involving low-frequency modes. This tentative, assumption appears independent of specific models…

Eine neue Methode zur Messung des anatomischen Totraumes mit Hilfe des Totluft-Plateaus

1975

Im Exspirationsrohr eines Atemventils, welches sich nahe am Mund des Probanden befindet werden gleichzeitig O2-Partialdruck mit einer O2-Elektrode und exspiriertes Volumen mit einem Pneumotachographen gemessen. Die PO2-Anzeige hat eine 90%-Einstellzeit von 40 ms. Wahrend der Totluft-Bolus die O2-Elektrode passiert, wird das sogenannte Totluft-Plateau gemessen. Das bis zum Ende des (korrigierten) Totluft-Plateaus exspirierte Volumen entspricht dem Totraumvolumen. Das Totluft-Plateau wird durch Stromungs- und Diffusionsverbreiterung im Respirationstrakt verkurzt. Die Verbreiterung wird im Exspirationsrohr simuliert, sowie mit einer zweiten O2-Elektrode gemessen und als Korrektur berucksichtig…

Die Stereochemie der Spaltung chiraler acyclischer quartärer Phosphoniumsalze zu tertiären Phosphinoxiden mit Alkalialkoholat

1975

Die beobachtete Brutto-Stereochemie der Spaltung chiraler acyclischer quartarer Phosphoniumsalze 1–5 zu tertiaren Phosphinoxiden 6–10 mittels Natriumathylat ist — mit einer Ausnahme — prinzipiell die gleiche wie bei der Spaltung der betreffenden Salze mit Natrium-hydroxid. Die Stereoselektivitat ist dagegen bei der Spaltung mit Alkoholat meist deutlich geringer als bei der Reaktion mit Natriumhydroxid. Stereochemistry of the Alkali Alcoholate-induced Fission of Chiral Acyclic Quaternary Phosphonium Salts to Tertiary Phosphine Oxides The stereochemical course of the sodium ethanolate-induced fission of chiral acyclic quaternary phosphonium salts 1–5 to tertiary phosphine oxides 6–10 is (with…

Is a low-mass Z° in general SU (2) ⊗ U (1) gauge theories compatible with experiment?

1975

Abstract It is shown that any simple SU (2) ⊗ U (1) gauge theory with a Z° mass much lower than the W ± mass leads to serious conflicts with experiment. The case of deep inelastic neutral current reactions is discussed in greater detail.

On the determination of the proton RMS-radius from electron scattering data

1975

It is shown that the proton rms radius should be determined from fitting a polynomial of second order to the low-q 2 form factors. The commonly used polynomial of first order yields radius values which are too small. The proton rms radius has been redetermined from an analysis of the electron scattering data measured at three laboratories. The best fit value is 〈r E 2 〉1/2=0.87±0.02 fm.

The decay of105Tc to levels in105Ru

1975

Theβ−-decay of 7.6-min105Tc has been investigated byβ- andγ-ray singles and coincidence measurements. The activities have been produced by thermal-neutron-induced fission of235U or239Pu and subsequent chemical separation of the technetium fraction from the fission product mixture. AQβ-value of 3.2±0.2 MeV has been determined. In a delayed coincidence experiment the lifetime of the first excited state in105Ru at 20.55 keV has been measured to be 340±15 nsec. A level scheme of105Ru is proposed and compared with the results of recent nuclear reaction studies like104Ru(d, p) and104Ru(n, γ). From beta branching ratios to levels in105Ru, ground state spin and parity of 5/2+ can be suggested for10…

Untersuchungen zur Hepatitis B-Antigen(HBAg)-Fixation an peripheren Lymphocyten und isolierten Leberzellen bei Patienten mit entz�ndlichen Lebererkra…

1975

Bei 127 Patienten mit verschiedenen entzundlichen Lebererkrankungen wurde die Fixation von HBAg an peripheren Lymphocyten untersucht. Bei 60 von diesen Patienten wurden im Parallelansatz die Fixation von HBAg an peripheren Lymphocyten und isolierten Leberzellen sowie die Fixation von IgG an isolierten Leberzellen gepruft.

Limiting concepts in extensional flow

1975

A characteristic feature of extensional flows is their potential capability of determining a stable, oriented structure in liquid materials containing elongated particles. With reference to flexible linear macromolecules, either in solution or as polymer melts, the limiting conditions under which such an oriented structure is actually possible are critically reviewed. It is seen that orientation can be obtained either when entanglements are present, i.e. when the polymer molecules form some sort of network, or, if the molecules behave entirely individually, only under very special circumstances. Further, if the objective is the “freezing” of the oriented structure in a partly crystalline, h…

Test of a separable approximation to a local soft-core potential in the three-body system

1975

Three-nucleon observables below the break-up threshold are calculated employing the pole approximation to the soft-core Malfliet-Tjon potentials. The results are compared in detail to those obtained with the local potentials and to those calculated with the usual Yamaguchi interactions.

Measurement of substrate-induced oxygen uptake during microsomal drug oxidation using a gold micro-electrode.

1975

1. A resin-coated gold micro-electrode has been used for polarographic determination of oxygen concentration in liver microsomal suspensions from phenobarbital-pretreated rats. 2. The rate of oxygen uptake on addition of an NADPH-regenerating system and the rate after addition of various substrates of the mixed function oxidase system were measured. The rate of oxygen uptake was faster in the presence of substrate than in the presence of NADPH alone. 3. Kinetic constants (Km and V max) for biphenyl, hexobarbital, ethylmorphine, naphthalene and SKF 525-A measured by this technique compare favourably with those obtained either by measurements of NADPH oxidation, or chemical measurements of su…