Showing papers by "Ludwig Maximilian University of Munich published in 1984"
TL;DR: In this paper, a model of density fluctuations in simple fluids and glasses is proposed and analyzed analytically and numerically, based on a microscopic theory developed recently, and a dynamical model is proposed for density fluctuations.
Abstract: Based on a microscopic theory developed recently, a dynamical model of density fluctuations in simple fluids and glasses is proposed and analyzed analytically and numerically. The model exhibits a liquid-glass transition, where the glassy phase is characterized by a zero-frequency pole of the longitudinal and transverse viscosities indicating the systems' stability against stress. This also implies an elastic peak in the density-fluctuation spectrum. Approaching the glass transition the slowing down of density fluctuations is controlled by the increasing longitudinal viscosity, which in turn is coupled via a nonlinear feedback mechanism to the slowly decaying density fluctuations. This causes a divergence of the structural relaxation time at a certain critical coupling constant ${\ensuremath{\lambda}}_{c}$. At the glass transition density fluctuations decay with a long-time power law $\ensuremath{\Phi}(t)\ensuremath{\sim}{t}^{\ensuremath{-}\ensuremath{\alpha}}$ with $\ensuremath{\alpha}=0.395$ and approaching the transition the viscosity diverges proportional to ${\ensuremath{\epsilon}}^{\ensuremath{-}\ensuremath{\mu}}$ and ${\ensuremath{\epsilon}}^{\ensuremath{-}\ensuremath{\mu}}$, where $\ensuremath{\epsilon}=|1\ensuremath{-}\frac{\ensuremath{\lambda}}{{\ensuremath{\lambda}}_{c}}|$ and $\ensuremath{\mu}=\frac{(1+\ensuremath{\alpha})}{2\ensuremath{\alpha}}$, ${\ensuremath{\mu}}^{\ensuremath{'}}=\ensuremath{\mu}\ensuremath{-}1$ below and above the transition, respectively. The long-time tail "paradox" in dense fluids is briefly discussed.
704 citations
TL;DR: It is found that sequences between −90 and −160 base pairs upstream of the coding region are essential for correct transcription in gene transfer experiments and may be involved in the control of immunoglobulin gene transcription.
Abstract: Transcription of the immunoglobulin κ light-chain genes depends on the presence of a TATA box upstream of the leader gene segment1,2 and is regulated by an enhancer sequence in the large intron3,4. In studying a rearranged mouse κ light-chain gene we have now found that sequences between −90 and −160 base pairs (bp) upstream of the coding region are essential for correct transcription in gene transfer experiments. This region contains the deca- and pentadecanucleotide sequences TNATTTGCAT and TGCAGCTGTGNCCAG, which we call dc and pd, respectively. Sequences related to dc and pd were found upstream of all human and mouse κ-chain variable region (Vκ) genes, upstream of λ-chain variable region (Vλ) genes, and within the mouse heavy-chain enhancer5,6. An inverted and complementary form of the dc element (ATGCAAATNA, called cd) occurs upstream of all heavy-chain variable region (VH) genes. The newly defined sequences may be involved in the control of immunoglobulin gene transcription.
509 citations
TL;DR: Carbene complexes have been shown to be suitable as carbene-transfer agents and undergo interesting cycloadditions with other ligands in the co-ligand sphere as mentioned in this paper.
Abstract: Transition metals are finding increasing use in organic synthesis on the borderline between “organic” and “inorganic” chemistry. Advantage is taken thereby of the fact that metal-induced CC bond formation often takes place with remarkable selectivity. The rapid development that has taken place in this area of chemistry is clearly demonstrated by the carbene complexes, examples of which are now known for almost all transition elements, and which have transformed from organometallic curiosities into synthetically useful reagents in less than two decades since the first studies of E. O. Fischer. They are not only suitable as carbene-transfer agents but also undergo interesting cycloadditions with other ligands in the co-ligand sphere. Their manipulation requires techniques no more complicated than those for Grignard reactions. Thus, carbene complexes can also be used in the synthesis of natural products such as vitamins or antibiotics.
481 citations
TL;DR: The topical and laminar distribution of corticotectal cells, as well as their size and morphology, were studied in the macaque monkey with the horseradish peroxidase (HRP) technique.
Abstract: The topical and laminar distribution of corticotectal cells, as well as their size and morphology, were studied in the macaque monkey with the horseradish peroxidase (HRP) technique. After HRP injections restricted primarily to the superficial layers of the colliculus, labelled cells were found in visual cortex (areas 17, 18, and 19) and both in the frontal eye field (area 8) and the adjacent part of premotor cortex (area 6). The clustering of labelled cells in visual cortex indicated that each of the anatomically and functionally distinct visual areas has its own set of collicular projections. When intermediate and deeper layers of the colliculus were injected, labelled cells were found also in posterior parietal cortex (area 7) where they were concentrated mainly on the posterior bank of the intraparietal fissure, in inferotemporal cortex (areas 20 and 21), in auditory cortex (area 22), in the somatosensory representation SII (anterior bank of sylvian fissure, area 2), in upper insular cortex (area 14), in motor cortex (area 4), in premotor cortex (area 6), and in prefrontal cortex (area 9). In the motor and premotor cortex, labelled cells formed a continuous band which appeared to stretch across finger-hand-arm-shoulder-neck representation. Similarly, the cluster of labelled cells in area 2 may correspond to the finger-hand representation of SII. The cortical regions not containing labelled cells were the somatosensory representation SI (areas 3, 1 and 2) and the infraorbital cortex. Labelled cells were restricted to layer V of all cortical areas except in the primary visual cortex, where labelled cells were found in both layer V and layer VI. The size spectrum of corticotectal cells ranged from 14.8 micron (average diameter) in area 17 to 27.8 micron in area 6, comprising cells as small as 8 micron and as large as 45 micron. Labelled cells in posterior parietal (area 7), in auditory (area 22), and in motor cortex (area 4) were small and distributed over only a narrow range of sizes. Those in premotor cortex (area 6) were often large and had a wide range in size distribution. The differences in size and morphology of corticotectal neurons suggest that they do not form a uniform class of neurons.
461 citations
TL;DR: It is shown here that the major urinary metabolite of endogenous prostaglandin I3 is present in subjects that have ingested either cod liver oil or mackerel, and provides the first direct evidence for in vivo formation of prostaglandsin I2 in man.
Abstract: Greenland Eskimos who live on a traditional marine diet rich in long chain omega 3-polyunsaturated fatty acids have a low incidence of cardiovascular disease and myocardial infarction. In their plasma and platelet lipids, arachidonic acid, the precursor of dienoic prostanoids, is partly replaced by eicosapentaenoic acid (C20:5, omega 3; EPA), the precursor of trienoic prostanoids. Studies with an Eskimo diet or a Western diet supplemented with sea fish or fish oil rich in EPA resulted in an 'Eskimo-like' pattern of plasma and platelet lipids. Moreover, less reactive platelets, a reduced ex vivo formation of proaggregatory thromboxane A2 and a blunted circulatory response to pressor hormones were reported. These favourable functional effects may be induced by a shift of prostanoid formation from the dienoic to the trienoic series. We show here that the major urinary metabolite of endogenous prostaglandin I3 is present in subjects that have ingested either cod liver oil (approximately 4 g EPA per day) or mackerel (approximately 10-15 g EPA per day). Our studies provide the first direct evidence for in vivo formation of prostaglandin I3 in man.
459 citations
TL;DR: The effective reflectance of the foam on the ocean surface together with the fraction of the surface covered with foam describes the optical influence of whitecaps in the solar spectral range, which leads to a good agreement with satellite measured radiances and albedo values.
Abstract: The effective reflectance of the foam on the ocean surface together with the fraction of the surface covered with foam describes the optical influence of whitecaps in the solar spectral range. This effective reflectance is found to be ~22% in the visible spectral range and is presented as a function of wavelength for the solar spectral range. With the fraction of the surface covered with foam, taken from the literature, the results lead to a good agreement with satellite measured radiances and albedo values. The effective reflectance is more than a factor of 2 lower than reflectance values used to date in remote sensing and radiation budget studies. Consequently, the optical influence of whitecaps can be assumed to be much less important than formerly supposed.
347 citations
TL;DR: In this paper, an analogue of the classical duality theorem of linear programming is established, imposing only weak conditions on the topology of the spaces Xi and the measurability resp. boundedness of the function h.
Abstract: Given topological spaces X1, ..., Xn with product space X, probability measures μi on Xi together with a real function h on X define a marginal problem as well as a dual problem. Using an extended version of Choquet's theorem on capacities, an analogue of the classical duality theorem of linear programming is established, imposing only weak conditions on the topology of the spaces Xi and the measurability resp. boundedness of the function h. Applications concern, among others, measures with given support, stochastic order and general marginal problems.
319 citations
TL;DR: It is concluded that a detailed history, physical examination, and basic laboratory tests are sufficient in most patients for the positive diagnosis of irritable bowel syndrome and the exclusion of any underlying organic diseases.
318 citations
TL;DR: The experience with extracorporeal shock wave lithotripsy (ESWL) and the new therapeutic aspects it has generated and the current state of technology are discussed.
305 citations
TL;DR: The reduced toxicity with full efficacy favours a low and infrequent dosage of aspirin, which effectively blocked platelet throm boxane formation and thromboxane-supported aggregation on collagen and was safe in the postoperative phase.
297 citations
TL;DR: The Carbenkomplexe eignen sich nicht nur als Carbenubertrager, sondern gehen auch interessante Cycloadditionen with weiteren Substraten aus der Coligandensphare ein this paper.
Abstract: An der Nahtstelle von „Organischer” und „Anorganischer” Chemie werden Ubergangsmetalle verstarkt in der Organischen Synthese angewendet. Dabei nutzt man die Erfahrung, das metallinduzierte CC-Verknupfungen oft bemerkenswert selektiv verlaufen. Der rasche Fortschritt wird am Beispiel der Carbenkomplexe deutlich, die heute von fast allen Nebengruppenelementen bekannt sind und die sich in weniger als zwei Jahrzehnten — seit den ersten Arbeiten von E. O. Fischer — von Raritaten zu nutzlichen Reagentien fur die Synthese entwickelt haben. Sie eignen sich nicht nur als Carbenubertrager, sondern gehen auch interessante Cycloadditionen mit weiteren Substraten aus der Coligandensphare ein. Ihre Handhabung erfordert keine aufwendigere Technik als fur Grignard-Reaktionen. So lassen sich Carbenkomplexe auch zur Naturstoffsynthese, etwa von Vitaminen oder Antibiotica, heranziehen.
TL;DR: In this paper, it was shown that desorption energies can be extracted from thermal desion spectra without any assumption on the preexponential, ν, regardless of coverage.
TL;DR: Investigation of the Kiel classification of non‐Hodgkin lymphomas found marked improvement of prognosis was solely possible by induction of complete remissions whereas in corresponding low‐grade malignant lymphomas also partial remissions were prognostically relevant.
Abstract: Clinical and prognostic relevance of the Kiel classification of non-Hodgkin lymphomas (NHL) was investigated in 1127 patients entering a prospective multicenter observation study Survival of the 782 (694 per cent) patients with low-grade malignant NHL (lymphocytic lymphomas, predominantly B-CLL, LP immunocytoma, centrocytic lymphoma, centroblastic-centrocytic lymphoma) exceeded that of the 341 patients (302 per cent) with high-grade malignant NHL (centroblastic, immunoblastic, lymphoblastic lymphomas) Prognosis was best in centroblastic-centrocytic lymphoma and in B-CLL and least favorable in immunoblastic and lymphoblastic lymphomas Survival of LP immunocytoma and centrocytic lymphoma patients was intermediate after 2 to 25 years of follow-up Corresponding to histopathology, pattern of survival curves of low-grade malignant NHL (slow decline, no plateauing) differed from that of high-grade malignant NHL (rapid decline, subsequent plateauing) Prognosis of B-CLL was superior to that of LP immunocytoma Stages I and II were more frequent in centroblastic-centrocytic lymphoma (21 per cent) than in LP immunocytoma (25 per cent) and centrocytic lymphoma (11 per cent) Ability of radiotherapy to induce stable complete remissions in stage III of centroblastic-centrocytic lymphoma indicates prolonged restriction of lymphoma to the lymphatic system In immunoblastic and centroblastic lymphomas, stages I and II were diagnosed in 34 and 38 per cent of cases, respectively, but only in stage I/IE of centroblastic lymphoma prolonged remissions were achieved by radiotherapy In advanced high-grade malignant NHL marked improvement of prognosis was solely possible by induction of complete remissions whereas in corresponding low-grade malignant lymphomas also partial remissions were prognostically relevant
TL;DR: Using serpentine fluorescence as an indicator of alkaloid production in cultured CATHARANTHUS ROSEUS cells, 6 cell lines producing alkaloids in excess of 300 mg/l were selected from more than 2 x 10 (5) individual colonies and their alkaloidal production was monitored over a period of 8 years.
Abstract: Using serpentine fluorescence as an indicator of alkaloid production in cultured CATHARANTHUS ROSEUS cells, 6 cell lines producing alkaloid in excess of 300 mg/l were selected from more than 2 × 10 5 individual colonies and their alkaloid production was monitored over a period of 8 years. Rapid loss of productivity invariably occurred during the first few months of cultivation, and spontaneous recovery of the initial production rates was never observed. Production of the indole alkaloid precursor, secologanin, followed the same pattern. Recovery of high alkaloid yielding strains was, however, possible at any time by repetition of the clonal selection procedure, but these strains were again instable. Clonal selection of high yielding plant cell strains apparently favours an inherent instability.
TL;DR: In this article, photoelectron spectroscopy and high-resolution electron energy loss spectrograms were used to identify a surface complex in which both nitrogen atoms interact with the metal and formed the immediate precursor to dissociation.
Abstract: ${\mathrm{N}}_{2}$ chemisorbed on Fe(111) is identified by photoelectron spectroscopy and high-resolution electron energy-loss spectroscopy as a $\ensuremath{\pi}$-bonded surface complex in which both nitrogen atoms interact with the metal. This species forms the immediate precursor to dissociation.
TL;DR: Color carboxymethylation of cysteine residues with a new chromophoric reagent dimethylaminoazobenzene iodoacetamide, was applied to the micro‐sequence analysis of hirudin, a thrombin specific inhibitor.
TL;DR: Echolocation has most probably evolved in context with catching flying insects which is illustrated by the fact that all but one genus of the frugivorous Megachiroptera do not echolocate at all, but instead feature excellent night vision.
Abstract: Sympatrically living echolocating bat species search for prey in different foraging zones. Structure of echolocation calls and audition are adapted to the specific foraging areas and hunting behaviors. Long pure-tone and narrow-band echolocation signals are described as adaptations to long-range echolocation and to fluttering-insect detection in echo cluttering environments. Echolocation with brief broadband signals is discussed in context with target texture discrimination and range finding by measuring echo travel times. I n the history of mammalian evolution the bats (Chiroptera) provide an impressive story of success. The well preserved fossiles from Grube Messel near Darmstadt and from Wyoming, USA tell us that already in the wake of mammalian development, some 50-60 million years ago, bats had achieved a status of sophisticated design as perfect as in recent species. Chiroptera ramified into more than 900 different species indicating that they enjoyed a niche of living little impaired by competitors from other mammalian stock or vertebrate phyla. Bats owe this flourishing existence to two unique specializations: they extended foraging on insects from the ground and vegetation into the air by developing wings and escaped the strong predatory impact of the faster flying birds by restricting their foraging flights to the night. This they could achieve because they integrated vocalization and audition into an effective echolocation system [1]. Echolocating bats emit brief sounds of high frequencies (15-200 kHz) through the mouth or the nostrils and listen to the echoes reflected from prey and objects around them. Due to the limited energy available in emitted sounds and sound absorption in air echolocation only operates over shorter distances of maximally 30-40 meters. The information from the echoes provides the bat with an auditory representation of its surroundings precise and good enough to do without any visual information. Thus unlike owls echolocating bats skillfully fly and catch prey in complete darkness [2]. Echolocation has most probably evolved in context with catching flying insects which is illustrated by the fact that all but one genus of the frugivorous Megachiroptera do not echolocate at all, but instead feature excellent night vision. Even though some echolocating bats have specialized on eccentric food like pollen, fish, frogs or warm blood most species feed on insects. In this report I shall focus the discussion on the insect-eating species. Sound recordings from about 150 of the more than 600 echolocating bat species have disclosed that the structure of echolocation pulses are widely diverse (e.g. [3-6], and many others). The frequency of the main energy emitted may range from 17 kHz to over 200 kHz and sound duration may vary from 0.3 to 200 ms. Echolocation pulses might be brief frequency-downward-modulated sweeps (FM) consisting of one to several harmonics which broaden the frequency band of the signal to up to 120 kHz. In other species, notably horseshoe bats and hipposiderids, sounds consist of combinations of long pure tones, so-called constant-fre-
TL;DR: A new low-molecular weight protein inhibitor of cysteine proteinases, human cystatin, was isolated from sera of patients with autoimmune diseases and is identical with human gamma-trace, a microprotein of known sequence but hitherto unknown function.
TL;DR: In this article, a selfconsistent theory for Frenkel excitons coupled to optical phonons is presented and tested by comparison with numerical calculations, and it is found that the mean-field approach fails to predict accurately vibronic excitations at the upper band edges of the exciton zero-and one-phonon bands.
TL;DR: In this paper, the authors report on their clinical experience in the use of extracorporeally generated, focused shock waves in the treatment of stone disease in the upper urinary tract.
TL;DR: It was concluded that the basic defects are a reduced excitability and an increased sodium conductance, and that these defects are aggravated on reduction of the extracellular potassium concentration.
Abstract: To study the mechanism of attacks in familial hypokalemic paralysis, we recorded resting membrane potentials, action potentials, current-voltage relationships, and isometric forces in intercostal muscle fibers from three patients. In normal extracellular medium, the resting potential was reduced, but membrane conductance was not different from control. Excitability was reduced and the action potentials had no overshoot. On exposure to a 1-mM potassium solution, with or without insulin, the cells depolarized to about -50 mV, and became inexcitable. Over the tested membrane potential range from -120 to -40 mV, the slope conductance in the 1-mM potassium solution was not different from that of control fibers in a 1-mM potassium solution. In particular, the potassium component conductance was not reduced. Depolarized fibers could not be completely repolarized by returning to a 3.5-mM potassium solution. An experimentally induced transient shift of the chloride equilibrium potential to a highly negative value caused stable repolarization. Paralysis could also be induced by replacement of extracellular chloride with an impermanent anion, a treatment which causes myotonia in healthy fibers. It was concluded that the basic defects are a reduced excitability and an increased sodium conductance, and that these defects are aggravated on reduction of the extracellular potassium concentration.
TL;DR: It is concluded that 85% of all patients with stones can be cured by nonsurgical means and an experienced urologic surgeon can best decide which of the available therapies is best suited for an individual patient.
Abstract: Four years of experience with extracorporeal shock wave lithotripsy (ESWL) for renal and ureteral calculi is summarized. Ninety-nine percent of treated patients had a satisfactory clinical result; 90% of them were stone-free. No significant complications were encountered. We conclude that 85% of all patients with stones can be cured by nonsurgical means. Surgical and other therapeutic modalities will still have a place in the future, but an experienced urologic surgeon can best decide which of the available therapies is best suited for an individual patient.
TL;DR: The concept that the release of kinins in the brain during an acute cerebral lesion mediates secondary damaging processes by the enhancement of blood–brain barrier dysfunction is supported.
Abstract: The effect of bradykinin on the permeability and vasomotor response of pial vessels has been studied to enhance our understanding of the pathophysiological role of the kallikrein-kinin system in cerebral tissue. Intravital fluorescence microscopy of the pia arachnoidea was conducted using Na+-fluorescein, FITC-dextran, and FITC-albumin as low and high molecular weight blood-brain barrier indicators. Massive arterial dilatation evolved immediately upon administration of bradykinin by superfusion of the exposed cerebral surface. An increase of the arterial diameter by 40% was the maximal response found at bradykinin concentrations of 4 x 10(-5) M. Arterial dilatation became attenuated with continuous superfusion of the preparation with bradykinin. In pial veins, a moderate reduction of the vessel diameter was observed, however, only after prolonged superfusion of the preparation. Bradykinin led to selective opening of the blood-brain barrier for Na+-fluorescein at superfusate concentrations of greater than or equal to 4 x 10(-7) M, but not for FITC-dextran or FITC-albumin. Topical administration of l-isoproterenol (10(-4) M) was found to prevent extravasation of Na+-fluorescein in the presence of bradykinin concentrations of 4 x 10(-6) M. Protection of the blood-brain barrier by isoproterenol was not observed when higher concentrations of bradykinin were employed. Intracarotid infusion of bradykinin were employed. Intracarotid infusion of bradykinin led also to a selective opening of the blood-brain barrier for Na+-fluorescein, but not for FITC-dextran or FITC-albumin. In contrast to superfusion, this route of administration did not induce changes of the vasomotor behavior of the arteries or veins. Additional experiments with B1-agonists and -antagonists suggest that bradykinin causes the openings of the blood-brain barrier th rough an interaction with B2-receptors on endothelial cells, and arterial dilatation via interaction with B2-receptors on vascular smooth muscle cells. Our findings support the concept that the release of kinins in the brain during an acute cerebral lesion mediates secondary damaging processes by the enhancement of blood-brain barrier dysfunction.
TL;DR: There is an effective overproduction of epithelial cells amounting to 10% per day in Hydra attenuata and evidence suggests that these excess cells are phagocytized by neighboring cells in the tissue.
TL;DR: In this paper, it was shown that the catalytic activity of carbons increases parallel to the incorporation of a nitrogen species which is pyridine-like, i.e. incorporated in the aromatic layers.
TL;DR: Significantly elevated antibody titers against ixodid tick spirochetes were observed in 45% of 44 cases with erythema migrans disease, in 72% of 29 cases of lymphocytic meningoradiculitis, in all of nine patients with acrodermatitis chronica atrophicans and in four investigated patients with lymphocytoma.
Abstract: An indirect immunofluorescence technique for the determination of antibodies against ixodid tick spirochetes is described. Differences in the reactivity between Ixodes ricinus spirochete and Ixodes dammini spirochete antigens were not observed. Cross-reacting antibodies against Treponema pallidum and Treponema phagedenis can be eliminated by quantitative absorption with T. phagedenis. Cross-reactions with leptospira were not observed by immunofluorescence. In the IgM test, false negative reactions caused by high-titered specific IgG antibodies or false positive reactions caused by rheumatoid factor occur. This can be avoided by testing the IgM fraction (19S-IgM-test) or using sera previously treated with anti-IgG serum. Significantly elevated antibody titers against ixodid tick spirochetes were observed in 45% of 44 cases with erythema migrans disease, in 72% of 29 cases of lymphocytic meningoradiculitis, in all of nine patients with acrodermatitis chronica atrophicans and in all of four investigated patients with lymphocytoma (lymphadenosis benigna cutis).
TL;DR: It is concluded that congestion of the outer medulla is a key event in ischemic renal failure, its occurrence is coincidental with the reduction in deep nephron perfusion and urinary concentrating power in the early and maintenance phase and its disappearance heralds the restoration of deep neephron perfusions and urinary concentrate ability in the recovery phase.
TL;DR: Transport of alkaloids across the tonoplast into the vacuolar space has been characterized as an active, engergy-requiring mechanism, which is sensitive to the temperature and pH of the surrounding medium and inhibited by N,N′-dicyclohexylcarbodiimid and Cu2+.
Abstract: Vacuoles were isolated from different plant cell cultures and the transport mechanism for alkaloid uptake at the tonoplast membrane, as well as the compartmentation of enzymes and products inside the cells were investigated. While serpentine, the major alkaloid of Catharanthus roseus cells, is definitely located inside the vacuole, two key enzymes of the indole-alkaloid pathway, strictosidine synthase and a specific glucosidase, are located in the cytosol. Transport of alkaloids across the tonoplast into the vacuolar space has been characterized as an active, engergy-requiring mechanism, which is sensitive to the temperature and pH of the surrounding medium, stimulated by K+ and Mg2+, and inhibited by N,N′-dicyclohexylcarbodiimid and Cu2+. The alkaloids accumulate inside the vacuoles against a concentration gradient, and the uptake system is specific for alkaloids indigenous to the plant from which the vacuoles have been isolated.