Showing papers by "Heidelberg University published in 1970"

On the interpretation of measurement in quantum theory

Abstract: It is demonstrated that neither the arguments leading to inconsistencies in the description of quantum-mechanical measurement nor those “explaining” the process of measurement by means of thermodynamical statistics are valid. Instead, it is argued that the probability interpretation is compatible with an objective interpretation of the wave function.

The genetic basis of the normal human electroencephalogram (EEG)

Abstract: The genetic basis of the normal human electroencephalogram (EEG) was analyzed. Twin investigations showed complete concordance for most EEG characteristics in monozygotic twins of all age groups. Differences in high age include focal abnormalities and dysrhythmic groups. These differences failed to show a relation to mental performance. For a number of special EEG variants, population frequencies were determined, and the mod of inheritance was established. The following variants were analyzed: 1. Variants of the alpha rhythm: a) The low voltage EEG (simple autosomal dominance), b) Borderline cases of the low voltage EEG (mixed genetic basis), c) Quick (16–19/sec) alpha variants (simple autosomal dominance), d) Slow (4–5/sec) alpha variants (mode of inheritance still unknown; behavioral abnormalities), e) Monotonous α-waves (probably simple autosomal dominance). 2. The EEG with β-waves: a) Differences in relation to age and sex were analyzed. β-waves are especially frequent in elderly women. b) Certain types of β-groups in frontal and precentral leads show a simple autosomal dominant mode of inheritance. c) For the diffuse β-waves, the general model of multifactorial inheritance in combination with a threshold effect seems to be appropriate.

Theory of a three-level gas laser amplifier

Abstract: A laser amplifier to be treated in this work consists of an ensemble of atoms three energy levels of which form two coupled transitions of arbitrary frequencies. Two classical monochromatic travelling light waves are to be close to resonance with the transitions. The gain profile (or spontaneous emission) on the transition corresponding to the weak “probe” wave, modified by the perturbing field on the other transition, is calculated via a susceptibility. Within this framework, the atoms are described by an ensemble-averaged density matrix with full account of level degeneracies, light polarizations, and inelastic and dephasing collisions; an extension to elastic collisions and disorientation is straightforward. An integration over the thermal velocity distribution gives results applicable to gas discharges: directionally anisotropic narrow structures superimposed on the Doppler-broadened probe-gain profile due to non-linear interference effects in addition to saturation. At alower probe frequency, a peculiar non-Lorentzian signal appears even with transparency on the perturbing transition. At low intensities a distinction is reasonable of frequency correlations due to generalized two-quantum processes, and of a dynamic Stark splitting. These effects permit an information on the linewidth of the third forbidden transition. The connection with numerous related approaches is pointed out.

The slow inward current and the action of manganese ions in guinea-pig's myocardium.

Abstract: In guinea-pig's myocardium the slow inward current, which seems to be related to the positive plateau of the myocardial action potential, was studied by voltage clamp technique. This current could be displayed when the initial rapid inward current was inactivated by shifting the holding potential to levels positive to the resting potential. The threshold potential for the slow inward current was about −40 mV and the current was maxium at depolarizations to between −10 mV and +10 mV. The reversal potential was about +70 mV. A similar slow inward current was obtained when the preparation was bathed either in a sodium-free solution which contained calcium ions or in a calcium-free solution which contained sodium ions. In the latter solution, the reversal potential was between +30 mV and +50 mV. It seems possible that not only calcium but also sodium ions contribute to the slow inward current in normal Tyrode's solution. Manganese ions in concentrations of 5–20 mM depressed the slow inward current, especially when the depolirizations were small. In a calcium-free solution, the amplitude of the slow inward current flowing during large depolarizations was increased by manganese ions. In a calcium and sodium-free solution, a slow inward current was obtained when manganese ions were present.

Initiation of RNA Synthesis: the Function of σ in the Binding of RNA Polymerase to Promoter Sites

Abstract: In the presence of σ, E. coli RNA polymerase forms rifampicin resistant complexes with DNA in the absence of nucleoside triphosphates. These complexes only form at promoter sites, so the number of σ-recognized promoters per genome for several DNA phages could be determined.

Effect of Sodium Restriction on Renal Hypertension and on Renin Activity in the Rat

Abstract: Control rats and rats with experimental renal hypertension due to unilateral stenosis of one renal artery received a standard diet (0.23% sodium) and a sodium-deficient diet (0.004% sodium), alternately, during which time blood pressure and plasma renin activity were determined. At the end of the experiment, renin content of the kidneys was measured. In normotensive control rats, the sodium-deficient diet did not affect blood pressure, but plasma renin activity and renin content of the kidneys increased. In rats with renal hypertension, restriction of sodium supply was followed by a fall in blood pressure to normotensive levels, provided that an intact contralateral kidney was present. Similarly, sodium-deficient diet prevented the development of hypertension if given immediately after placing the clip on one renal artery. Restriction of sodium supply provoked a marked increase in plasma renin activity, whereas renin content of the ischemic kidney was only slightly, but significantly, higher than in rats with normal sodium intake. Contrary to this, in unilaterally nephrectomized rats with renal hypertension, neither hypertension nor plasma renin activity or renin content of the kidneys was affected by sodium-deficient diet. In control rats with unilateral nephrectomy, plasma renin activity was only half that of intact rats, and restriction of sodium provoked no more than an increase up to normal values of intact rats. Sodium loss by the contralateral kidney may contribute to both the antihypertensive effect of a sodium-deficient diet and the increase in plasma renin activity.

The structural implications of the linear electrical properties of cardiac Purkinje strands.

Abstract: An attempt has been made to decide upon the most reasonable equivalent circuit that will describe the passive linear properties of the Purkinje strands of sheep heart muscle. In order to do this, measurements were made of the phase angle of the characteristic admittance as well as the longitudinal impedance, both as functions of frequency. The results of both types of experiments indicate the presence of a longitudinally oriented capacity with a time constant of about 60–70 µsec. It is suspected that this capacity and time constant represent the connection between the cells, both radially and longitudinally. The plasma membrane contains another capacity with a time constant of about 15 msec.

Voltage and Time Dependence of Excitatory Sodium Current in Cooled Sheep Purkinje Fibres

Abstract: Very small Purkinje fibre preparations were cooled down to 4–5°C in order to slow the activation of the excitatory sodium current to such an extent that the latter could be separated from the capacitive membrane current. Although the resting potential of the membrane decreased to −30 mV at the low temperature, it was possible to trigger the sodium carrying system by conditioning the membrane with hyperpolarizing pulses applied under voltage clamp conditions. The sodium currents flowing after sudden depolarizations starting from various conditioning prepotentials and going to various clamp potentials were analyzed according to the Hodgkin-Huxley equations. It turned out that the results could be satisfactorily fitted by the equations, although the absolute values and the potential dependences of the rate constants differed from those found for the squid giant axon in a characteristic manner. Particularlyh, the variable describing the inactivation of the sodium carrying system, had a remarkable potential dependence at the low temperature extending from unity at a potential as high as −180 mV to zero at a potential −100 mV. The time course of the removal of inactivation showed a similar dependence on conditioning prepotential and time to that found for the squid giant axon. Conditioning pulses of up to 10 s were necessary to remove inactivation at a prepotential of −110 mV. The decay of the sodium current flowing after depolarizations from various conditioning prepotentials to the same clamp potential differed from that of the squid axon in a way that it could better be fitted by two time constants rather than one. By comparison of the data with those obtained from experiments carried out at 20°C extrapolations of the results to body temperature were made. These suggest that at 37°C the sodium carrying system should be almost entirely inactivated when the action potential reaches its crest.

Untersuchungen zur Taxonomie, Biologie und Ökologie einiger Köcherfliegenarten der Gattung Hydropsyche Pict. (Insecta, Trichoptera)

Abstract: Taxonomic and Ecological Studies on Some Species of Hydropsyche Pict. (Insecta, Trichoptera)

Struktur der Triarymethyl-Dimeren

Abstract: 13C-NMR-Spektren des [α-13C]Triphenylmethyl-Dimeren, dessen Synthese beschrieben wird, beweisen die Struktur 3 fur das dimere Triphenylmethyl (1). Das 1H-NMR-Spektrum des Tris-[4-deutero-phenyl]-methyl-Dimeren bestatigt ebenfalls die Interpretation der Protonenresonanz des 1-Dimeren2 im Sinne der Formel 3. Fur das 9-Phenyl-fluorenyl-Dimere wird dagegen auf Grund des 1H-NMR-Spektrums die Struktur eines echten Hexaarylathans 4 vorgeschlagen. Structure of Triarylmethyl Dimers Structure 3 is confirmed for the dimer of triphenylmethyl (1) by 13C. n.m.r. spectra of [α-13C]triphenylmethyl dimer, the synthesis of which is described. The interpretation given for the proton resonance of 1-dimer2 is also supported by the 1H. n.m.r. spectrum of tris-(4-deuterophenyl)methyl dimer. However, for 9-phenylfluorenyl dimer the hexaarylethane structure 4 is proposed on the basis of the 1H. n.m.r. spectrum.

Single unit responses in the cervical sympathetic trunk upon somatic nerve stimulation.

Abstract: 1. In cats anesthetized with chloralose single unit activity was recorded from filaments of the cervical sympathetic trunk dissected caudal to the upper cervical ganglion. The characteristics of the spontaneous and evoked spike discharges of these preganglionic units upon somatic nerve stimulation were studied. The vagus and carotid sinus nerves were cut. 2. More than 500 units were identified. Their conduction velocities ranges from 20 m/s to less than 0.5 m/s. The units with conduction velocities below 2 m/s (28% of our sample) were considered to be unmyelinated fibers. The peak of the conduction velocity histogram of the myelinated fibers was at 4–6 m/s. 3. Both in the myelinated and in the unmyelinated fiber range mainly two types of sympathetic units were found: about 70% were not spontaneously active and did not exhibit evoked discharges, whereas 25% had both properties. The other 5% had either one or the other property. 4. As a rule the evoked response of a unit consisted of one spike only. More rarely units with 2–4 evoked discharges per stimulus were seen. In any given unit the evoked discharges occurred with a certain propability, which, for the majority of units, was between 40–60% in a series of 20 trials. 5. The sympathetic units responded either to cutaneous volleys, or to cutaneous and muscle volleys. No units were seen which responded to a muscle afferent volley but not to a cutaneous one. 6. The spontaneous activity was of low frequency. In the myelinated fiber range the average was 1.7 Hz. In the unmyelinated fiber range an average of 2.9 Hz was found. Following somatic nerve stimulation the spontaneous discharge was reduced or abolished for periods up to 1 s independent of the occurrence of an evoked response. The maximum depression appeared immediately after the onset of the inhibition.

The Oxygen Effect

Abstract: The term “oxygen effect” refers to the observation that the radiation sensitivity of macromolecules and biological systems irradiated in the presence of oxygen or air is generally higher than when they are irradiated under vacuum or in an inert atmosphere. This only applies, however, with ionizing radiations; in UV irradiation experiments, an oxygen effect is only rarely observed. As with the temperature effect, justice is not done to the oxygen effect by treating it merely as a troublesome side-effect of radiation action. It is actually a phenomenon of great heuristic importance for the elucidation of the molecular nature of radiation damage. It is a pity that here, as in many other aspects of radiation biology, relevant experiments are scarce and the many facets of the oxygen effect tend in general to produce confusion rather than understanding. It is therefore not surprising that there is no satisfactory interpretation of the oxygen effect as yet. Nevertheless, an attempt will be made to describe the oxygen effect quantitatively, with the aid of known physico-chemical data and taking specific aspects of the inactivation of microorganisms into account. The chemical mechanisms underlying the oxygen effect will be studied, in the light of experiments on the radiation inactivation of biological macromolecules.

Über einige Strukturbesonderheiten der Suspensorzellen vonPhaseolus vulgaris

Abstract: Die Suspensorzellen vonPhaseolus vulgaris wurden nach Anzucht unter verschiedenen Temperaturbedingungen elektronenmikroskopisch untersucht. Auffallige Strukturbesonderheiten sind ein gut entwickeltes, glattes endoplasmatisches Reticulum (das manchmal auch im Karyoplasma vorkommt), Wandprotuberanzen und Piastiden von sehr unterschiedlicher, oft bizarrer Form und verschiedenen Binnenstrukturen. Von den unregelmasig geformten, hoch endopolyploiden Kernen werden gelegentlich degenerierende Plasmainseln eingeschlossen. Die Suspensorzellen beiPhaseolus unterscheiden sich in ihrer Feinstruktur sehr von denen beiCapsella; ihre mogliche Funktion wird diskutiert.

Zur Spaltung tertiärer Phosphine. I

Abstract: Durch Kommutieren von 1-Phenylphospholan und 1-Phenylphosphorin mit Phosphortrichlorid bei 280° erhalt man 1-Chlor-phospholan, C4H8PCl, und 1-Chlor-phosphorin, C5H10PCl, die mit Schwefel oder Chlor oxidiert werden konnen. Hydrolyse in Gegenwart von Wasserstoffperoxid ergibt Tetramethylen- und Pentamethylen-phosphin-, saure. Reduktion mit Lithiumaluminiumhydrid fuhrt zu cyclischen, sekundaren Phosphinen dem 1-Phospholan, C4H8PH und dem 1-Phosphorin, C5H10PH. Commutation of 1-phenylphospholane and 1-phenylphosphorin with phosphorus trichloride at 280°C yields 1-chlorophospholane, C4H8PCl, and 1-chlorphosphorin, C5H10PCl, respectively which may be oxidized by elemental sulphur or chlorine, and hydrolyzed in the presence of hydrogen peroxide to from tetramethylene- and pentamethylene-phosphinic acid. Reduction by means of LiAlH4 gives the cyclic secondary phosphines 1-phospholane, C4H8PH, and 1-phosphorin, C5H10PH.

The Temperature Effect

Abstract: In Chapter 5, target molecular weights for various enzymes were calculated from the 37%-doses measured at room temperature, and the results compared with the true molecular weights of the irradiated biomolecules. As there is no rational reason to attach any special significance to the results obtained at room temperature, the dependence of inactivation rate on the temperature during exposure will now be examined. In some ways, this chapter could be considered as an extension of the target theory; furthermore, some additional features of the indirect effect (see Chapter 6) will become apparent, the significance of which is enhanced by the observation of a remarkable uniformity in the temperature-dependence of many biological systems under irradiation.

Zur Konjugation in makrocyclischen Bindungssystemen, XV. Benzo[12]annulene: 5.6.11.12.17.18-Hexadehydro-tribenzo[a.e.i]cyclododecen

Abstract: 5.6-Didehydro-tribenzo[a.e.i]cyclododecen (6) wurde ausgehend von 2.2′- Bis-brommethyl-diphenylacetylen durch doppelte Wittig-Reaktion mit Phthaldehyd erhalten. Bromierung von 6 und HBr-Eliminierung ergab 5.6.11.12.17.18-Hexadehydro-tribenzo[a.e.i]cyclododecen (1). UV-, IR-, Raman-und 1H-NMR-Spektren von 1 sowie das ESR-Spektrum des 1-Radikal-anions werden unter dem Gesichtspunkt der starren ebenen Tribenzo[12]annulen-Struktur von 1 und der Intramolekularen Wechselwirkung zwischen den Dreifachbindungen diskutiert. Uber Isomerisierungs-und Komplexbildungsversuche mit 1 wird berichtet. Conjugation in Macrocyclic Systems, XV. Benzo[12]annulenes: 5,6,11,12,17,18-Hexadehydrotribenzo[a, e, i]cyclododecene 5.6-Didehydrotribenzo[a,e,i]cyclododecen (6) was obtained by a double Wittig reaction with phthaldialdehyde starting from 2.2′-bis-(bromomethyl)diphenylacetylene. Bromination of 6 and HBr elimination yielded 5,6,11,12,17,18-hexadehydrotribenzo[a, e, i]cyclododecene (1). U.v., i.r., Raman and 1 H n.m.r. spectra of 1 and the e.s.r. spectrum of 1-radicalanion are discussed with regard to the rigid planar benzo[12]annulene structure of 1 and to the intramolecular interactions between the triple bonds. Experiments on isomerisation and complex formation of 1 are reported.

Der Aminosäuren-Stoffwechsel des normalen menschlichen Gehirns

Abstract: Bei 15 gesunden freiwilligen Versuchspersonen haben wir die Hirndurchblutung, die cerebrale Aufnahme von Sauerstoff und Glucose sowie die Abgabe von Kohlensaure und Lactat aus dem Gehirn gemessen. Ferner wurden die cerebralen arteriovenosen Differenzen von Taurin, Harnstoff, Asparaginsaure, Threonin-Asparagin, Serin, Glutaminsaure, Prolin, Citrullin, Glycin, Alanin, Valin, Cystin, Methionin, Isoleucin, Leucin, Tyrosin, Phenylalanin, Ammoniak, Ornithin, Lysin und Histidin bestimmt. Die fur den Normalfall ermittelten Werte von Hirndurchblutung, Sauerstoff- und Glucoseverbrauch des Gehirns sowie Abgabe von Kohlensaure und Milchsaure aus dem Gehirn stimmen mit denen anderer Untersucher uberein. Die Differenzen der Aminosaurenkonzentrationen zwischen arteriellem und hirnvenosem Mischblut zeigten im Durchschnitt entweder eine positive (Aufnahme), negative (Abgabe) oder keine Differenz. Lediglich die sog. glucoplastischen Aminosauren zeigten eine grosere cerebrale arteriovenose Differenz. Unter normalen Bedingungen findet zwar ein Austausch von Aminosauren zwischen Blut und Hirngewebe statt, die entscheidende Bildung von Aminosauren erfolgt jedoch erst im Gehirn in dem um einen γ-Aminobuttersaure-shunt erweiterten Krebscyclus. Normalerweise werden in die beiden im Gehirn befindlichen Aminosaurepools mehr Aminosauren eingeschleust als fur funktionelle oder strukturelle Aufgaben notwendig ist, so das der „Uberschus“ aus dem Gehirn abgegeben wird.

Electrical activity and metabolism in cardiac tissue: An experimental and theoretical study

Abstract: (1) Effects of the metabolic inhibitor 2,4-dinitrophenol (DNP) on electrical activity in frog atria were studied by means of the sucrose-gap technique and in tracer experiments. (2) Voltage-clamp studies of ionic membrane currents showed a suppression by DNP of peak Na inward current without marked changes in the kinetics of the Na-carrying system and an increase of steady state outward current to three to five times its normal value. In42K tracer experiments, DNP increased K resting efflux by about 10% and decreased K influx by 25 to 30%. (3) The depression of Na inward current is regarded as being caused by a partial block of Na channels and an increase of internal Na concentration after inhibition of active Na extrusion. (4) The strong rise in outward current is probably not caused by a K current since K efflux fails to show a correspondingly large change. As a possible explanation for current and flux changes, an electrogenic K pump is discussed. (5) A mathematical model of a carrier system transporting a single ion species is described. The system is designed as a direct “potential” pump. Uphill transport requires an asymmetry of the rate constants governing the cyclic formation and breakdown of carrier-ion complex. The asymmetry is brought about by an input of metabolic energy. Reduction of energy input decreases the asymmetry and induces a carrier-mediated downhill ion movement, with corresponding changes in membrane current and ion fluxes. (6) A model of electrogenic K inward transport is calculated that approximately accounts for the steady state current and the K flux changes experimentally observed after inhibition.

An analysis of the reflex activity in the cervical sympathetic trunk induced by myelinated somatic afferents.

Abstract: 1. The characteristics of the mass reflex response recorded monophasically from the cervical sympathetic trunk upon somatic nerve stimulation were studied in cats anesthetized with urethane and/or chloralose. The vagus and carotid sinus nerves of the animals were cut. 2. A single peripheral stimulus evoked a mass discharge with three initial negative deflections (components) having latencies of about 40, 70 and 110 ms respectively. Occasionally a small forth component with a latency of 280 ms was seen. Thereafter the potential became more positive than the control value. The negative deflections were the result of evoked spike discharges in the trunk fibers, whereas the positive deflection was due to the inhibition of the spontaneous spike activity (post-excitatory-depression, silent period). 3. There was a considerable variability of the amplitudes and latencies of the different components both in a succession of trials in the same animal and in different animals, but through the use of averaging techniques it was shown that the basic pattern was always preserved. No relation was found between the variability of sympathetic and of somatic reflexes evoked by the same afferent input. The variability of the sympathetic reflexes was not locked to the cardiac or to the respiratory cycle. 4. Volleys in low threshold cutaneous fibers (Group II fibers) were by far the most powerful afferents in evoking sympathetic reflexes. If cutaneous Group III fibers were included in the volley there was a further increase in reflex size. Activation of Group I afferents from muscle never produced sympathetic reflexes, but Group II and III afferents were quite effective. 5. The reflexes were followed by a silent period (post-excitatory-depression) during which the spontaneous discharge and the reflex effects of afferent volleys were suppressed. The time course of this silent period was investigated for a variety of conditioning-testing situations.