Showing papers by "Ludwig Maximilian University of Munich published in 1977"
TL;DR: All available colloid volume substitutes carry the risk of anaphylactoid reactions, but the frequency of severe reactions was low for plasma-protein solutions, hydroxyethyl starch, 0-008% for dextran, and 0-038% for gelatin solutions.
1,053 citations
TL;DR: The work function at first decreases, exhibits a (temperature-dependent) minimum at θ = 13, attains nearly the value of the clean surface at 12 and again exhibits a second (shallow) minimum around 0.68 as mentioned in this paper.
721 citations
TL;DR: Starch synthesis in leaves was increased by phosphate starvation or by treatments which decreased cytoplasmic orthophosphate levels (such as mannose feeding) and it is suggested that this control is exerted via the phosphate translocator and the known allosteric regulation of ADP-glucose pyrophosphorylase.
Abstract: Starch synthesis in leaves was increased by phosphate starvation or by treatments which decreased cytoplasmic orthophosphate levels (such as mannose feeding). Usually less than 30% of the total carbon fixed during CO(2) assimilation was incorporated into starch in spinach (Spinacia oleracea L.), spinach beet (Beta vulgaris), and tobacco (Nicotiana tabacum) leaves.In isolated spinach chloroplasts, formation of starch from CO(2) was usually less than in leaves. In the absence of significant levels of 3-phosphoglycerate, concentrations of phosphate as low as 1 mm (in the medium) or 10 mm (in the stroma) almost completely inhibited starch synthesis. The inhibitory action of phosphate could be overcome by 3-phosphoglycerate. The controlling factor of starch synthesis appeared to be the ratio of phosphoglycerate to orthophosphate rather than the stromal hexose monophosphate concentration, and it is suggested that this control is exerted via the phosphate translocator and the known allosteric regulation of ADP-glucose pyrophosphorylase. Starch synthesis was also favored by the presence of dihydroxyacetone phosphate and by high light and high temperature. Oxygen was inhibitory, probably owing to carbon drain into glycolate. Starch formation by intact chloroplasts could not be promoted by added glucose or glucose 6-phosphate.Starch mobilization in the dark was promoted by orthophosphate and phosphate-dependent mobilization was inhibited by phosphoglycerate. The principal products of starch breakdown in the presence of phosphate were the transport metabolites dihydroxyacetone phosphate and 3-phosphoglycerate. Formation of these compounds from starch was stimulated by ATP or oxaloacetate. In a phosphate-independent reaction, starch was also converted to neutral products such as maltose and glucose. The rates of phosphate-dependent starch degradation phosphorolysis were very much higher than those of starch hydrolysis for which there was no phosphate requirement.
374 citations
TL;DR: In this article, the adsorption of N2 on clean Fe(100) and Fe(111) single-crystal surfaces was studied in the temperature range 140-1000 K by means of Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), ultraviolet photoelectron spectroscopic (UPS), thermal-desorption (TDS) and work-function measurements (Δφ).
349 citations
TL;DR: It appears conceivable that in ventricular myocardium endogenously formed adenosine may serve 2 functions: dilation of the coronary arteries and limitation of the inotropic and metabolic effects of catecholamines.
Abstract: Infusion of adenosine into the coronary arteries of isolated guinea pig hearts produced a dose-dependent inhibition of dP/dtmax caused by bolus injections of isoproterenol (4 X 10(-11) moles). Threshold concentration of adenosine was 10(-7) M and maximal inhibition (90%) occurred at 10(-5) M. Coronary dilation induced by papaverine did not influence the contractile response to catecholamines. In addition to its influence on cardiac performance, adenosine (10(-5) M) effectively inhibited the isoproterenol (10(-7)M) induced initial rise in myocardial levels of cyclic 3'5'-AMP, glucose-1-phosphate and glucose-6-phosphate. Adenosine also antagonized the effect of isoproterenol on adenylate cyclase activity in a crude membrane preparation from guinea pig ventricles; it was without effect on the activity of the membrane phosphodiesterase. Theophylline inhibited the actions of adenosine both on adenylate cyclase activity and on contractile force development. Upon infusion of isoproterenol (3 X 10(-7)M) into the coronary arteries of the isolated heart (perfusion at constant pressure), the adenosine concentration in the effluent perfusate increased within 45 s from 10(-8) M to about 10(-6) M. It thus appears conceivable that in ventricular myocardium endogenously formed adenosine may serve 2 functions: dilation of the coronary arteries and limitation of the inotropic and metabolic effects of catecholamines.
343 citations
TL;DR: In this article, the adsorption of NO on Pd(111) was studied by means of LEED, UPS and thermal desorption measurements, and the results showed that the strong decrease of the adorption energy was explained in terms of pronounced short-range repulsive interactions between neighbouring adsorbate molecules.
289 citations
TL;DR: The surface region of Pd(111) is characterized by three different types of oxygen atoms, which may be distinguished by their thermal, chemical, structural and electronic properties as discussed by the authors.
280 citations
TL;DR: The adsorption of hydrogen on Fe(110, (100) and (111) single crystal planes has been studied by means of low energy diffraction (LEED), thermal desorption spectroscopy (TDS), work function measurements and ultraviolet photoelectron spectroscopic (UPS).
269 citations
TL;DR: In this article, the formation of two ordered surface structures (I and II) was observed with two equivalent domain orientations with the mirror plane along the [001] direction, and it is most probably that these large unit cells reflect the reconstruction of the topmost layer of Fe atoms.
230 citations
224 citations
TL;DR: Oleic acid found in Tween 80 as well as in Cremophor El seems to be the most effective constituent, but the alcohol seems also to be important for the histamine-releasing capacity.
Abstract: Several preparations of Cremophor El®, several of other non-ionic detergents and several components of Cremophor El were tested for their histamine-releasing capacity in dogs. Lutensol AP 10 and a derivative of 1,2-propylenglycol were ineffective, but showed excellent properties as detergents. Thus the histamine-releasing capacity was not necessarily combined with the tenside effect of the surfactants. Oleic acid found in Tween 80 as well as in Cremophor El seems to be the most effective constituent, but the alcohol seems also to be important for the histamine-releasing capacity. The development of a non-toxic solubilizer for lipophilic drugs seems of considerable clinical interest.
TL;DR: In this article, the authors give an algebraic condition in order that a completely positive dynamical semigroup of an N-level system has a unique (invariant) equilibrium state and that every initial state approaches this equilibrium state as t→∞.
Abstract: We give an algebraic condition in order that a completely positive dynamical semigroup of an N-level system has a unique (invariant) equilibrium state and that every initial state approaches this equilibrium state as t→∞. We apply our result to a semigroup arising in the weak coupling limit.
TL;DR: It is concluded that under these conditions the ATP-ADP exchange is largely electrical.
Abstract: The relation between the intramitochondrial and extramitochondrial ratio ATP/ADP, the transmembrane potential and pH gradient is investigated in the present communication. For this purpose mitochondria are equilibrated with added [14C]ATP in the presence of substrate and oligomycin for eliminating phosphate transfer by ATPase. The membrane potential was measured by the distribution of 86Rb+ in the presence of valinomycin, the deltapH by the distribution of [14C]acetate. In the energized state by varying deltapsi between 60 and 160 mV, the internal (ATP/ADP)i is decreased 30-fold, the external (ATP/ADP)e remains largely constant. As a result, the deltalog (ATP/ADP)e/(ATP/ADP)i = deltalogphi is increased linerly with deltapsi according to the following relation: deltalogphi = 0.85 deltapsi - 0.35. The deltapH was changed between 0.1 and 0.8 by increasing the Pi concentration causing only a minor decrease of deltalogphi would be expected if the ATP-ADP exchange has a significant electroneutral portion. Also in the uncoupled and respiration-inhibited state the same function between deltalogphi and deltapsi is found as in the energized states. It is concluded that under these conditions the ATP-ADP exchange is largely electrical.
TL;DR: The data indicate that the greater part of the adaptive changes of vascular resistance during hypoxia and autoregulation can be attributed to adenosine which is formed at an enhanced rate under these conditions, however, other factors might be involved as well.
Abstract: In an attempt to test the hypothesis whether adenosine is involved in the regulation of coronary flow, adenosine, inosine and hypoxanthine were measured in the effluent perfusate and in the tissue of isolated guinea pig hearts under various experimental conditions. In addition, the release of14C-adenosine,14C-inosine and14C-hypoxanthine was determined after prelabeling cardiac adenine nucleotides with14C-adenine.
TL;DR: In this article, a 1:2-Komplexe with AuCl, Aul, and AuCH3 is described, and the results are of interest with respect to the short but nonbonding AuAu distance.
Abstract: Bis(diphenylphosphino)methan bildet 1:2-Komplexe mit AuCl, Aul und AuCH3 (1a–c). Auch von 2,2-Bis(diphenylphosphino)propan kann ein analoger AuCl-Komplex erhalten werden (2a). Zusatzlich zur ublichen analytischen und spektroskopischen Charakterisierung werden Au-Mosbauer- und Au-ESCA-Spektren aufgenommen und von 1a eine Rontgenstrukturanalyse angefertigt. Die Ergebnisse sind wegen des kurzen, aber nichtbindenden AuAu-Abstandes von Interesse.
Gold Complexes of Diphosphinomethanes, I. Synthesis and Crystal Structure of Binuclear Gold(I) Compounds
Bis(diphenylphosphino)methane forms 1:2 complexes of AuCl, Aul, and AuCH3 (1a–c). From 2,2-bis(diphenylphosphino)propane an analogous AuCl complex could also be obtained (2a). in addition to the usual analytical and spectroscopic characterization, Au-Mosbauer and Au-ESCA spectra have been recorded, and an X-ray analysis of 1a has been carried out. The results are of interest with respect to the short, but nonbonding AuAu distance.
TL;DR: Bromocriptine (CB 154), which suppressed PRL, improved glucose tolerance and decreased insulin towards normal in a second OGTT, might be a useful drug in improving glucose utilization in hormone-active pituitary tumours.
Abstract: During an oral glucose tolerance test (OGTT) glucose and insulin levels were measured in 26 patients with prolactin-producing pituitary tumours without growth hormone excess. Basal glucose and insulin levels did not differ from the values of an age-matched control group. After glucose load the hyperprolactinaemic patients showed a decrease in glucose tolerance and a hyperinsulinaemia. Bromocriptine (CB 154), which suppressed PRL, improved glucose tolerance and decreased insulin towards normal in a second OGTT. — Human PRL or CB 154 had no significant influence on insulin release due to glucose in the perfused rat pancreas. — These findings suggest a diabetogenic effect of PRL. CB 154 might be a useful drug in improving glucose utilization in hormone-active pituitary tumours.
TL;DR: Neither muramic acid and glucosamine nor d-glutamic acid or other amino acids typical of peptidoglycan were found in cell walls of two strains of Methanosarcina barkeri, and the structural component of the cell wall most likely consists of an acid heteropolysaccharide, resembling that of Halococcus morrhuae.
Abstract: Neither muramic acid and glucosamine nor d-glutamic acid or other amino acids typical of peptidoglycan were found in cell walls of two strains of Methanosarcina barkeri. The main components are galactosamine, neutral sugars and uronic acids. Therefore, the structural component of the cell wall most likely consists of an acid heteropolysaccharide, resembling that of Halococcus morrhuae. It is, however, not sulfated.
TL;DR: It is concluded that d-glucose and other hexoses are transported by carrier-mediated diffusion across the inner envelope membrane, similar to the transport of d- glucose into erythrocytes.
Abstract: The uptake of radioactively labeled hexoses and pentoses into the sorbitol-impermeable (3)H(2)O space (the space surrounded by the inner envelope membrane) of spinach (Spinacia oleracea L.) chloroplasts has been studied using silicone layer filtering centrifugation. Of the compounds tested, d-xylose, d-mannose, l-arabinose, and d-glucose are transported most rapidly, followed by d-fructose and l-arabinose. The rate of l-glucose uptake is only about 5% of that of d-glucose.The transport of d-glucose and d-fructose shows saturation characteristics, the K(m) for d-glucose was found to be about 20 mm. All sugars transport and phloretin inhibit d-glucose transport. The temperature dependency of d-glucose transport appears to have an activation energy of 17 kcal/mol.With low external concentrations of d-glucose the transport into the chloroplasts proceeds until nearly the external concentration is reached inside the chloroplasts.d-glucose transport is inhibited by high d-glucose concentrations in the medium. It is concluded that d-glucose and other hexoses are transported by carrier-mediated diffusion across the inner envelope membrane. This transport is similar to the transport of d-glucose into erythrocytes.
TL;DR: The formation of metabolites in the stroma compartment of isolated chloroplasts during carbon fixation, and their export to the medium, have been investigated using improved techniques and it was concluded that the efflux of phosphoglycerate was restricted.
TL;DR: The results suggest that newly synthesized mitochondrial proteins exist in an extra-mitochondrial pool from which they are imported into the mitochondria.
Abstract: The transport of cytoplasmically synthesized mitochondrial proteins was investigated in whole cells of Neurospora crassa, using dual labelling and immunological techniques. In pulse and pulse-chase labelling experiments the mitochondrial proteins accumulate label. The appearance of label in mitochondrial protein shows a lag relative to total cellular protein, ribosomal, microsomal and cytosolic proteins. The delayed appearance of label was also found in immunoprecipitated mitochondrial matrix proteins, mitochondrial ribosomal proteins, mitochondrial carboxyatractyloside-binding protein and cytochrome c. Individual mitochondrial proteins exhibit different labelling kinetics. Cycloheximide inhibition of translation does not prevent import of proteins into the mitochondria. Mitochondrial matrix proteins labelled in pulse and pulse-chase experiments can first be detected in the cytosol fraction and subsequently in the mitochondria. The cytosol matrix proteins and those in the mitochondria show a precursor-product type relationship. The results suggest that newly synthesized mitochondrial proteins exist in an extra-mitochondrial pool from which they are imported into the mitochondria.
TL;DR: Blood volume was studied in infants and children aged from one hour to 14 years and linear and logarithmic regression equations relating blood volume to weight, height and surface area were calculated.
Abstract: Blood volume was studied in 160 infants and children aged from one hour to 14 years. From these data linear and logarithmic regression equations relating blood volume to weight, height and surface area were calculated. Equations utilizing combined weight and logarithmic weight values were found to be the most accurate for predicting blood volume. Therefore, nomograms were constructed for reading blood volume directly from height and weight.
TL;DR: In this article, the photoabsorption cross section of molecular H2O and D2O has been determined in the range from hν = 10eV to 20 eV with 0.03 A resolution.
TL;DR: In the case of α-cyano-cis-stilbene oxide, the disrotatory process was shown to occur in this article, which was predicted by the Woodward-Hoffmann rules.
Abstract: Substituents capable of stabilizing negative charge endow ethylene oxides with the ability to undergo electrocyclic ring opening at the CC bond; heating or irradiation generates small equilibrium concentrations of carbonyl ylides which can engage in 1,3-dipolar cycloadditions. Apart from the normal conrotatory mode of ring opening, predicted by the Woodward-Hoffmann rules, the disrotatory process, forbidden by orbital symmetry, also appears to occur in the case of α-cyano-cis-stilbene oxide. Kinetic studies on α-cyano-trans -and -cis-stilbene oxide permit construction of the energy profile for electrocyclic ring opening to give the stereoisomeric carbonyl ylides and for their recyclization and rotation.
TL;DR: A procedure for the isolation of large quantities of pure mitochondrial DNA from these mitochondria is described and further purification of the mitochondria by urografin isopycnic centrifugation leads to 50% recovery of whole cell respiration activity in a vesicular fraction of respiratory chain enzymes.
TL;DR: It is concluded that the satellite DNA, which appears homogeneous by digestion with endo R-EcRII, contains distinct segments each susceptible to degradation with one of the other nucleases, which has certain implications for theories on the evolution of mouse satellite DNA.
Abstract: The long-range periodicity of mouse satellite DNA has been analyzed by digestion with five restriction nucleases. With all nucleases tested, a major repeat unit approximately 245 nucleotide pairs became apparent. Minor registers of shorter length were also detected. The total number of cleavage sites per haploid genome for each restriction enzyme as well as their positions relative to each other were determined. While endo R-EcoRII was known to cleave all of the satellite DNA, the other four restriction enzymes were found to generate only weak degradation patterns. The results taken together with quantitative analyses of codigestion experiments indicate that the recognition sequences for each of these four nucleases are clustered on separate parts of the satellite DNA. It is concluded that the satellite DNA, which appears homogeneous by digestion with endo R-EcRII, contains distinct segments each susceptible to degradation with one of the other nucleases. These results have certain implications for theories on the evolution of mouse satellite DNA. A simple mechanism of multiplication and divergence by mutation is not sufficient to explain the data. Additional and alternative processes which are relevant to the evolutionary considerations are discussed.
TL;DR: In this paper, the photoabsorption cross section of molecular N 2 has been determined in the range from 10-35 eV utilizing the continuum of synchrotron radiation from the DORIS storage ring.
TL;DR: In this paper, the X-ray structure analysis shows that the two gold atoms of the centrosymmetric eight-membered ring are surrounded by two phosphorus and one chlorine atom in an approximately trigonal planar configuration.
Abstract: Aus Bis[(chloroaurio)diphenylphosphino]methan (1) entsteht mit weiterem Bis(diphenylphosphino)methan eine metallocyclische Verbindung 2, die in polaren Losungsmitteln nur wenig dissoziiert ist und in ein Tetraphenylborat 3 umgewandelt werden kann. — Die Rontgenstrukturanalyse zeigt, das die beiden Goldatome des centrosymmetrischen achtgliedrigen Ringsystems angenahert trigonal planar von zwei Phosphoratomen und einem Chloratom umgeben sind. Gleichzeitig bilden die beiden Metalle eine auffallend kurze Au–Au-Achse (296 pm), die auf den P2AuCl-Ebenen senkrecht steht. Sie last auf eine transannulare Metall-Metall-Wechselwirkung schliesen.
Gold Complexes of Diphosphinomethanes, II. Synthesis and Crystal Structure of Eight-membered Heterocycles of Gold(I) with Au–Au Interaction
From bis[(chloroaurio)diphenylphosphino]methane (1) and additional bis(diphenylphosphino)-methane a metallocyclic complex 2 is formed which is only slightly dissociated in polar solvents. The chloride can be converted into a tetraphenylborate 3. — The X-ray structure analysis shows that the two gold atoms of the centrosymmetric eight-membered ring are surrounded by two phosphorus and one chlorine atom in an approximately trigonal planar configuration. The two metals form a surprisingly short Au–Au axis (296 pm), which lies perpendicular to the P2AuCl planes, indicating a transannular metal-metal interaction.
TL;DR: There was a significantly diminished ratio of subendocardial/subepicardial flow in the hypertrophy group during moderate exercise, which indicates an insufficient growth of the vascular bed in these hypertrophied hearts.
Abstract: Left ventricular hypertrophy was induced by banding of the ascending aorta in puppies at the age of 6 weeks At the age of one year left ventricular weight per body weight was increased by 87% compared to control litter mates While myocardial perfusion and myocardial oxygen consumption per 100 g were identical in the hypertrophy and control group, there was a significantly diminished ratio of subendocardial/subepicardial flow in the hypertrophy group during moderate exercise With maximal coronary dilation subendocardial diastolic resistance (mm Hg/ml · min-1 per 100 g) was 016 ± 003 in the control group and 026 ± 003 in the hypertrophy group This diminished coronary reserve indicates an insufficient growth of the vascular bed in these hypertrophied hearts
TL;DR: The main purpose of this paper is to prove Miyadera's theorem on perturbations of semigroup generators under reduced assumptions as discussed by the authors, and to obtain the perturbed semigroup by an iteration similar to the iteration used in the proof for bounded perturbation.
Abstract: The main purpose of this note is to prove Miyadera's theorem on perturbations of semigroup generators (Miyadera [4]; see Remark 2, c) below) under reduced assumptions. In our proof we obtain the perturbed semigroup by an iteration similar to the iteration used in the proof for bounded perturbations. By an example we show that the theorem is optimal with respect to a constant occurring in the theorem. In the followingX will be a Banach space. For a linear operator TinX we denote by D(T) its domain of definition and by R(T) its range. ~(X) denotes the bounded linear operators X ~X. A s.c. (strongly continuous) semigroup on X is a family (W(t);t>O) in ~(X) satisfying W(0) = I, W(t t + t2)= W(t,)W(t2) (tl, t2 =>0), [0, oo)~t~-~W(t)x is continuous (x6X). A s.c. semigroup satisfies an estimate If W(t)H < Le ~ (t ~ 0). The linear operator T defined by D(T)" = {xeX;Tx:= lim t-'(W(t)-I)x exists} t~O+
TL;DR: It is suggested that cytoplasmically synthesized mitochondrial proteins exist in an extramitochondrial pool prior to import; that the site of this pool is the cytosol for at least some of the mitochondrial proteins; and that the precursors in the extamit mitochondrial pool differ in structure or conformation from the functional proteins in the mitochondria.
Abstract: The results suggest that the transport of cytoplasniically synthesized mitochondrial proteins is essentially independent of cytoplasmic translation ; that cytoplasmically synthesized mitochondrial proteins exist in an extramitochondrial pool prior to import; that the site of this pool is the cytosol for at least some of the mitochondrial proteins; and that the precursors in the extramitochondrial pool differ in structure or conformation from the functional proteins in the mitochondria. In the preceding paper we studied the transport of cytoplasmically synthesized proteins into the mitochondria in intact cells of Neurosporu crassu [l]. la whole cells, the processes of synthesis and transport are not easily separated. Furthermore, post-labelling fractionation artifacts may obscure the intracellular location of mitochondrial proteins which are on their path from the site of synthesis to the site of function. In considering systems in vitro a number of possibilities exist, ranging Crom cell-free homogenates to reconstituted systems involving isolated and purified protein and organelle components. In the present study we have investigated synthesis and transport in a cell-free homogenate. We. have employed this system in an attempt lo decide between two mechanisms currently proposed for the transport of mitochondria] proteins. The first mechanism is based on observations with whole IC’emrospora cells [l]. This mechanism proposes the existence of extramitochondrial pools of mitochondrial proteins from which they are imported into the mitochondria. The second mechanism is that proposed by Butow and his colleagues [3 - 61. This latter mechanism proposes a special class of cytoplasmic ribosomes which are attached to the mitochondria at specific sites. The nascent polypeptides from these ribosomes are discharged in a vectorial manner into the mitochondria. The results we present here support our earlier proposal on the existence of extrarnitochondrial precursors of mitochondria1 proteins [I, 21.