Showing papers by "University of Göttingen published in 1979"
TL;DR: GIP, although important, is not the onlyincretin, and an exaggerated GIP response (usually secondary to the disease) may participate in the pathogenesis of hyperinsulinaemia of patients with obesity and duodenal ulcer.
Abstract: 1.|The insulinogenic factor of the gastrointestinal mucosa named“incretin” is only one part of the complex enteroinsular axis. — 2. Of the chemically defined gastrointestinal hormones GIP is the strongestincretin candidate. — 3. Because of the dual function of GIP as gastrone and insulinotropic substance several safeguards against GIP-mediated insulin hypoglycaemia exist. — 4. No pathological condition has yet been found which is causally related to hyper- or hyposecretion of GIP. However, an exaggerated GIP response (usually secondary to the disease) may participate in the pathogenesis of hyperinsulinaemia of patients with obesity and duodenal ulcer. — 5. The injection of GIP antibodies only partially abolishes theincretin effect. Therefore, GIP, although important, is not the onlyincretin.
691 citations
TL;DR: The findings suggest that myocardial infarction had been caused by thrombotic occlusion in four patients, and that spasm of the infarct vessel could have been an additional factor in two of these patients.
Abstract: In five patients with acute myocardial infarction, the effects of both intracoronary nitroglycerin (NTG) and subsequent intracoronary streptokinase application were evaluated. In addition, transluminal recanalization was performed in one of these patients. Injection of NTG into the infarct-related coronary artery resulted in improved distal filling of the subtotally occluded left circumflex artery in one patient, and in transient patency of the completely occluded right coronary artery in a second patient. In a third patient patency of the totally occluded left anterior descending artery (LAD) was achieved by transluminal recanalization with a guide wire. In a forth patient with occulsion of the LAD, there was no response to intracoronary NTG and mechanical recanalization was not attempted. Subsequent intracoronary infusion of streptokinase (1,000--2,000 U/min for 15--60 min) resulted in a further and long-term reduction of narrowing at the site of acute occlusion in patients I-III and in opening of the completely occluded LAD in patient IV. Improvement of lumen was paralleled by alleviation of symptoms. In a fifth patient, in whom the LAD was subtotally occluded, the degree of coronary obstruction could not be changed by intracoronary application of NTG or by lysis. In this patient, symptoms and ECG changes improved with reduction of pathologically elevated blood pressure values. The findings suggest that myocardial infarction had been caused by thrombotic occulsion in four patients, and that spasm of the infarct vessel could have been an additional factor in two of these patients. In the fifth patient, an increase of afterload in the presence of a subtotal lesion might have caused the critical imbalance between oxgen supply and demand, resulting in cell death.
382 citations
TL;DR: Improved speech quality is obtained by efficient removal of formant and pitch-related redundant structure of speech before quantizing, and by effective masking of the quantizer noise by the speech signal.
Abstract: Predictive coding methods attempt to minimize the rms error in the coded signal. However, the human ear does not perceive signal distortion on the basis of rms error, regardless of its spectral shape relative to the signal spectrum. In designing a coder for speech signals, it is necessary to consider the spectrum of the quantization noise and its relation to the speech spectrum. The theory of auditory masking suggests that noise in the formant regions would be partially or totally masked by the speech signal. Thus, a large part of the perceived noise in a coder comes from frequency regions where the signal level is low. In this paper, methods for reducing the subjective distortion in predictive coders for speech signals are described and evaluated. Improved speech quality is obtained: 1) by efficient removal of formant and pitch-related redundant structure of speech before quantizing, and 2) by effective masking of the quantizer noise by the speech signal.
376 citations
TL;DR: In this article, the authors used hot-film sensors and flush-mounted wall elements to study the vortex structures associated with the bursting phenomenon and found that pairs of counter-rotating streamwise vortices occur frequently in the wall region of a bounded turbulent shear flow.
Abstract: The streamwise and spanwise velocity components and the gradients of these components normal to the wall were examined by using hot-film sensors and flush-mounted wall elements to study the vortex structures associated with the bursting phenomenon. Quadrant probability analysis and conditional sampling techniques indicated that pairs of counter-rotating streamwise vortices occur frequently in the wall region of a bounded turbulent shear flow. A streamwise momentum defect occurred between the vortices as low-speed fluid was ‘pumped’ away from the wall by the vortex pair. The defect region was long and narrow and possibly forms the low-speed streak as observed in visualization studies. The velocity defect was terminated by a strong acceleration followed by a high speed region.
296 citations
TL;DR: In this article, the transition from the steady to the oscillatory Marangoni convection in a floating zone under reduced influence of the gravity is visualized by means of the already proved method of light-cut-technique.
232 citations
TL;DR: The membrane-bound hydrogenase of Alcaligenes eutrophus was solubilized from washed membranes of autotrophically grown cells and reacted only with few artificial electron acceptors.
232 citations
TL;DR: A detailed experimental study of the susceptibility at the spin-glass transition in (Eu,Sr)S is presented in this article exhibiting a strong sensitivity of $\ensuremath{\chi}({T}{f})$ and ${T}_{f}$ to small external magnetic fields and different measuring frequencies.
Abstract: A systematic experimental study of the magnetic properties in insulating ${\mathrm{Eu}}_{x}{\mathrm{Sr}}_{1\ensuremath{-}x}\mathrm{S}$ is reported, giving evidence of spin-glass behavior for concentrations $0.13l~xl~0.5$ due to short-ranged exchange interactions with opposite sign. The magnetic properties below the spin-glass transition temperature ${T}_{f}$ are explored by low-field magnetization, ac susceptibility, and neutron-diffraction measurements. The magnetization and remanent magnetization are found to depend on the thermomagnetic history. An unusually pronounced maximum is observed in the thermoremanent magnetization as function of the previously applied field. The saturation values of the remanent magnetizations remain only a few percent of the saturation magnetizations, even for the high Eu concentrations. Their temperature, field, and time dependence are studied. Comparison is made with metallic spin-glass samples. A detailed experimental study of the susceptibility at the spin-glass transition ${T}_{f}$ in (Eu,Sr)S is presented exhibiting a strong sensitivity of $\ensuremath{\chi}({T}_{f})$ and ${T}_{f}$ to small external magnetic fields and different measuring frequencies. In an attempt to analyze the data, the distinction between the spin-glass phenomenon and superparamagnetism is stressed. Near the percolation threshold of the exchange interactions, ${x}_{p}=0.13$, a transition from spin-glass behavior to "pure" superparamagnetism is clearly observed in ${\mathrm{Eu}}_{x}{\mathrm{Sr}}_{1\ensuremath{-}x}\mathrm{S}$.
215 citations
TL;DR: The results suggest the presence of at least two forms of UDP-glucuronyltransferase in rat liver, and factors affecting enzyme activity in purified and membrane-bound states are discussed.
Abstract: Glucuronidation reactions catalysed by rat liver microsomal UDP-glucuronyltransferase are differentially inducible by 3-methylcholanthrene and phenobarbital. To elucidate the molecular basis of this functional heterogeneity the enzyme was purified from livers of rats pretreated with the inducing agents.
Using cholate solubilization, chromatography on Bio-Gel A-1.5m and on DEAE-cellulose in the presence of the nonionic detergent Brij 58, two enzyme forms could be separated. Both forms were subsequently purified to apparent homogeneity by affinity chromatography on UDP-hexanolamine Sepharose 4B. 3-Methylcholanthrene-inducible enzyme activity towards 1-naphthol, 4-nitrophenol, 3-hydroxybenzo(a)pyrene and N-hydroxy-2-naphthylamine copurified with one enzyme form (enzyme 1). In contrast phenobarbital-inducible enzyme activity towards morphine, chloramphenicol and 4-hydroxybiphenyl was associated with the other enzyme fraction (enzyme 2). Sodium dodecylsulfate/polyacrylamide gels showed similar molecular weights of 54000 for enzyme 1 and 56000 for enzyme 2.
The results suggest the presence of at least two forms of UDP-glucuronyltransferase in rat liver. Factors affecting enzyme activity in purified and membrane-bound states are discussed.
207 citations
TL;DR: Results of this pilot study suggest that transluminal recanalization in the early phases of acute myocardial infarction might result in limitation ofMyocardial injury.
Abstract: In 7 patients, the recently occluded infarct-related vessel was recanalized by transluminal catheter techniques during acute myocardial infarction (Group A). 4 patients had single-vessel disease, 2 patients two-vessels disease and one, involvement of three vessels. Control angiography was performed in 6 patients, 8 days to 7 months later. Changes of coronary artery anatomy and left ventricular function were compared with a group of 9 conventionally treated patients, who were found to have occlusion of the infarct-related vessel in the acute stage (Group B). Five Group B patients had one-vessel disease, 3 patients two-vessel disease and 1 patient, involvement of all three vessels. In the chronic stage, all transluminally recanalized vessels were found to be patent in Group A. There was spontaneous recanalization of the infarct vessel in 4 of 9 Group B patients. In Group A, the length of the akinetic segment (AKS) decreased significantly (p less than 0.05) from 145.4 +/- 48.5 mm to 73.2 +/- 73.4 mm (mean +/- SD). Volume parameters did not change significantly. In Group B, length of the AKS did not change significantly, EDVI increased significantly from 81.1 +/- 19.8 to 106.8 +/- 4.6 ml/m2 (p less than 0.05); ESVI increased significantly from 41.7 +/- 13.7; ml/m2 to 66.8 +/- 37.9 ml/m2 (p less than 0.01). In the acute stage, length of the AKS and volume parameters did not differ significantly between the two groups. In the chronic stage, AKS was significantly shorter (A: 73.2 +/- 63.4 mm; 144.9 +/- 59 mm (p less than 0.0025) and EF was significantly higher (A: 54.6 +/- 11.6%; B: 40.9 +/- 14.5% (p less than 0.05) in Group A. Peak CPK was lower in Group A (A: 1009 +/- 827 U/l; B: 1324 +/- 655 U/l), but this difference did not achieve statistical significance. Results of this pilot study suggest that transluminal recanalization in the early phases of acute myocardial infarction might result in limitation of myocardial injury. However, further research will be needed to improve the technique and to test its results.
175 citations
TL;DR: In this paper, a theoretical model is derived in which isotopic fractionations can be calculated as a function of variations in dissolved carbonate species on CO 2 degassing and calcite precipitation.
161 citations
TL;DR: A new genus of marine methanogenic bacteria and two species within this genus are described, which are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern.
Abstract: A new genus of marine methanogenic bacteria and two species within this genus are described.Methanogenium is the proposed genus andMethanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells ofMethanogenium marisnigri are of similar shape but smaller diameter thanM. cariaci. The colonies ofM. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens.
TL;DR: The evidence presented indicates that the ADP/ATP carrier is synthesized as a polypeptide with the same molecular weight as the mature monomeric protein and does not carry an additional sequence.
Abstract: ADP/ATP carrier protein was synthesized in heterologous cell-free systems programmed with Neurospora poly(A)-containing RNA and homologous cell-free systems from Neurospora. The apparent molecular weight of the product obtained in vitro was the same as that of the authentic mitochondrial protein. The primary translation product obtained in reticulocyte lysates starts with formylmethionine when formylated initiator methionyl-tRNA (fMet-tRNAfMet) was present. The product synthesized in vitro was released from the ribosomes into the postribosomal supernatant. The evidence presented indicates that the ADP/ATP carrier is synthesized as a polypeptide with the same molecular weight as the mature monomeric protein and does not carry an additional sequence.
TL;DR: The spatial relationship of interstitial metazoans to sources of oxygen has been studied on a tidal flat in the Wadden Sea near Sylt and it is found that a specific meiofauna confined to oxygen-deficient horizons of the sediment does not exist.
Abstract: The spatial relationship of interstitial metazoans to sources of oxygen has been studied on a tidal flat in the Wadden Sea near Sylt (eastern part of the North Sea). Consistently, meiofauna remains in close proximity to oxygenated layers or pocket areas within the sediment. This is exemplified by the pattern of meiofaunal abundance and species composition alongside oxic burrows of the lugworm Arenicola marina L. A specific meiofauna confined to oxygen-deficient horizons of the sediment does not exist.
TL;DR: The pronounced temperature dependence and characteristic lineshape of the signals obtained with hydrogenase in 80--85% dimethylsulphoxide demonstrated that iron-sulPHur centres of both the [2Fe-2S] and [4Fe-4S] types are present in the enzyme.
TL;DR: It is concluded that the initial capacity to augment the glucose-induced insulin release (incretin activity) of hydrochloric acid is due to its ability to release GIP, which is a direct effect of intraduodenal acid.
TL;DR: Silver-staining in the nuclei and chromosomes of spermatogenesis of four species of mammals was investigated qualitatively and quantitatively and reveals minor differences between the species investigated with regard to the times and extents of maximum activation.
Abstract: Silver-staining in the nuclei and chromosomes of spermatogenesis of four species of mammals (Man, Mus musculus, Rattus norvegicus, and Cavia cobaya) was investigated qualitatively and quantitatively. These species show a very similar pattern of activity of the nucleolus organizer regions (NORs) during the various stages of spermatogenesis. Silver precipitates are detectable in growing spermatogonia and up until the pachytene stage of meiotic prophase. During the meiotic metaphases I and II and during interkinesis silver-stainability disappears completely. A resumption of silverstainability occurs in round spermatids indicating a postmeiotic reactivation of NORs. This process does not persist beyond the early elongation phase. The quantitative determination of the silver-covered areas in relation to the total nuclear areas reveals minor differences between the species investigated with regard to the times and extents of maximum activation. The known localizations of the NORs in the karyotypes of the species investigated was confirmed using metaphase-preparations derived from somatic tissues.
01 Jan 1979
TL;DR: In this paper, an experimental study to establish the basic mechanisms of transition from deflagration to spherical detonation downstream of flow obstructions has been performed, and it was found that large scale eddies are essential for detonation.
Abstract: An experimental study to establish the basic mechanisms of transition from deflagration to spherical detonation downstream of flow obstructions has been performed. The flow obstructions consist of circular and rectangular orfice plates, multiple rectangular orifice plates and circular hole perforated plates. In order to keep the apparatus reasonably small and also to facilitate photographic observations at low initial pressures, acetylene-oxygen mixtures at equimolar composition were used throughout. The principal diagnotics were stereoscopic streak and framing schlieren photography. The apparatus consists of a spherical flame chamber connected to a cylindrical detonation chamber via an orifice plate mounted in the port-hole connecting the two chambers. The mechanism of detonation initiation is found to be due to the intense mixing of the hot combustion products with the unburned gases. Large scale eddies are found to be essential for detonation. These eddies provide the main mechanism of entrainment, and are also partially responsible for providing energy to maintain the intensity of the finer scale turbulence. When wire screens are used in conjunction with the orifice plates, the formation of detonation is facilitated, indicating that the fine scale turbulence which is produced plays a role in rapid mixing of the entrained gases inside the large scale eddies. Under critical conditions, when the initiation results from one single eddy, it appears that shock wave amplification by coherent energy release (SWACER) inside an eddy, where a gradient field of induction time due to entrainment is present, is most probable. This suggests that the minimum size of the required eddies must be at least of the order of the detonation kernel (i.e., transverse wave spacing) of the mixture. The present experimental findings that the obstructions which produce eddies of size of the order of transverse wave spacing lead readily to detonation initiation support this view.
TL;DR: It is concluded that in the Wadden Sea abundance of permanent meiofauna (Nematoda, Turbellaria, Ostracoda, Copepoda) is only locally or temporarily regulated by macrobenthic predators.
Abstract: The role of meiofauna in the trophic web of marine ecosystems is a controversial topic. During an experimental study on tidal flats in the eastern part of the North Sea, potential predators on meiofauna were kept in enclosures. A gobiid fish, shrimp, crabs, an amphipod, four polychaete worms and a nemertine were tested for their ability to decimate nematodes, turbellarians, ostracods and benthic copepods. Only few macrobenthic species preyed heavily on permanent meiofauna: juveniles of the shore crabCarcinus maenas, the hermit crabPagurus bernhardus with the colonial hydrozoanHydractinia echinata on its shells, and the rag wormNereis diversicolor. When benthic infauna was protected from these predators with exclosures, juvenile macrofauna responded with a marked increase in number, while the permanent meiofauna remained unaltered except for a limited increase in nematodes. It is concluded that in the Wadden Sea abundance of permanent meiofauna (Nematoda, Turbellaria, Ostracoda, Copepoda) is only locally or temporarily regulated by macrobenthic predators.
TL;DR: It is demonstrated that apocytochrome c synthesized in a heterologous cell-free system can be converted to holocy tochrome c by addition of mitochondria isolated from Neurospora cells.
TL;DR: Any indices that do not incorporate potentially important changes of MV⩽O2 related to both myocardial contractility and ventricular dimensions show unsatisfactory correlations with MV̇O2 at extreme changes of hemodynamics.
Abstract: The purpose of this study was to examine any reported indices for estimating myocardial oxygen consumption (MVO2) under uniform experimental conditions at maximal variation of hemodynamics and MVO2. One hundred sixty-two steady states were analyzed in 10 closed-chest dog experiments. Myocardial blood flow was directly measured by a differential pressure catheter in the coronary sinus. The indirect values of MVO2 calculated from 24 indices were compared with directly measured MVO2. Throughout a wide range of hemodynamic states, the best correlate with MVO2 was found to be the additive parameter Et (r = 0.96). Any indices that do not incorporate potentially important changes of MVO2 related to both myocardial contractility and ventricular dimensions show unsatisfactory correlations with MVO2 at extreme changes of hemodynamics. Tension-time index (TTI) correlates poorly with MVO2 (r = 0.63). This result is due to the neglect of contractility. Pressure-heart rate product (P × HR) correlates with MVO2 with r = 0.86. Better results for TTI and P × HR, as reported in previous works, are reproducible by dividing our data into two groups of different inotropic states. At normal and moderate inotropic stimulation the correlation for TTI rises to r = 0.96, and for P × HR to r = 0.91. This augmentation is to be referred to the close relationship (r = 0.92) of peak ventricular pressure to maximum rate of pressure rise in this group. The additive parameter Et is the best, both at moderate (r = 0.97) and at maximal inotropic stimulation (r = 0.87), and is to be preferred for indirect estimation of MVO2. Results are discussed with regard to the clinical application of MVO2 indices.
TL;DR: The selection of groups of MS patients with particular symptomatology and course of the disease for prospective, detailed study resulted in a pathognomonic pattern highly indicative of the diagnosis of MS.
TL;DR: The ratio of methanogenic to acetogenic bacteria in sludge and lake sediment samples has been found to be approximately 100 to 1 and Acetogenic bacteria could not be detected in rumen samples.
Abstract: A method has been worked out that allows the detection and isolation of bacteria fermenting molecular hydrogen and carbon dioxide to acetic acid. The ratio of methanogenic to acetogenic bacteria in sludge and lake sediment samples has been found to be approximately 100 to 1. Acetogenic bacteria could not be detected in rumen samples.
TL;DR: Theα-glucosidehydrolase inhibitor (α-GHI) exerted a potent inhibitory effect on glucoamylase, sucrase, and maltase, was minimally effective on isomaltases, and did not affect trehalase and lactase activity.
Abstract: The effect of a new complex oligosaccharide (Bay g 5421) of microbial origin on human intestinalα-glucosidehydrolase activity was tested in mucosal homogenate from human small bowel biopsy specimens.
TL;DR: It is concluded that the increased nitrate reductase activity after light onset is regulated via nitrate uptake, and evidence for a regulation in this direction is shown by the action of ammonium in terms of the regulation of the nitrate consuming system.
Abstract: Nitrate uptake was followed continuously in cultures of Chlorella sorokiniana using ionsensitive electrodes. During the lifecycle of the synchronous cell cultures, a drastic increase occurred in the first hour after the onset of the light. Nitrate uptake rate was shown to be dependent on illumination intensity, nitrate concentration, and temperature. These results point to an energy-linked uptake process. From the different timecourses of nitrate uptake rate and nitrate reductase activation, one can conclude that the increased nitrate reductase activity after light onset is regulated via nitrate uptake. Further evidence for a regulation in this direction is shown by the action of ammonium on nitrate uptake and nitrate reductase activity. The results are discussed in terms of the regulation of the nitrate consuming system.
TL;DR: Rapid diagnosis of acute hepatitis B infection is therefore now possible in those cases which are HBsAg‐negative but anti‐HBc‐positive, provided the sample was diluted in an excess of aggregated IgG.
Abstract: IgM antibody against core antigen of the hepatitis B virus (anti-HBc IgM) was selectively determined by a new enzyme immunoassay (EIA). Microtiter plates were coated with anti-human micro chain immunoglobulin. On addition of serum IgM is bound by a factor of about 4,000 more than IgG. After removing the sample, HBcAg is added to the IgM-coated surface. Binding takes place if the IgM contained anti-HBc and was demonstrated by the aid of a conjugate made from anti-HBc IgG and horse radish peroxidase. Quantitation may be achieved without testing a dilution series. The assay was not disturbed by a large excess of anti-HBc IgG in the sample and rheumatoid factor did not produce false-positive results, provided the sample was diluted in an excess of aggregated IgG. The diagnostic relevance of the assay was demonstrated in selected cases of acute hepatitis B. Rapid diagnosis of acute hepatitis B infection is therefore now possible in those cases whihc are HBsAg-negative but anti-HBc-positive.
01 Jan 1979
TL;DR: In this paper, the influence of low concentrations of alkali and alkaline-earth metals on soot particle size and number density in atmospheric-pressure premixed flat flames was investigated using laser light scattering and extinction measurements.
Abstract: The influence of low concentrations of alkali and alkaline-earth metals on soot particle size and number density in atmospheric-pressure premixed flat flames is investigated using laser light scattering and extinction measurements. Additions of the alkali metals (Na, K, Cs) only weakly suppress the total amount of soot formed, but they do result in a greater number (up 25 times) of particles than in the unseeded flame. The number of soot particles present correlates with the observed ability of the additive to promote ionization (Cs>K>Na) in the early stages of soot formation. It is proposed that incipient soot particles are charged earlier in the presence of these metals—once charged, these particles resist further collisional growth, so that their number density remains high and their size small. Of the alkaline-earth metlas (Ca, Sr, Ba), only Ba produces enough ions to suppress coagulation in the manner of the alkali metals. However, these metals, Ba included, do reduce the amount of soot formation. These results provide evidence that the influence of metallic additives involves both electrical and chemical factors.
TL;DR: The relationship between HLA determinants on effector and target cells and cell-mediated cytotoxicity was studied using the release of 51Cr from measles virus-infected PHA-blasts and it is suggested that HLA-dependent killer cells represent specific cytotoxic T lymphocytes.
Abstract: The relationship between HLA determinants on effector and target cells and cell-mediated cytotoxicity was studied using the release of 51Cr from measles virus-infected PHA-blasts. HLA compatibility between effector and target cells was not required if effector lymphocytes were derived from measles seropositive adults, from a patient with SSPE, and from children after live measles vaccination. Cytotoxicity was always abolished after removal of Fc receptor-bearing lymphoid cells. In these donors, the effect is, therefore, probably due to K cells. In contrast, lymphocytes from children with acute measles preferentially killed those virus-infected target cells with which they shared HLA antigens. Selective lytic activity was still observed after elimination of Fc receptor-bearing lymphoid cells. It is suggested that HLA-dependent killer cells represent specific cytotoxic T lymphocytes. These cells seem to be limited to the acute phase of measles.
TL;DR: Pigment preparations of 800 μm thickness and Golgi studies of the isocortex in juvenile neuronal ceroid-lipofuscinosis revealed giant axonal dilatations of IIIab-pyramids and severe numerical reduction of neurons in the ganglionic layer.
Abstract: Pigment preparations of 800 micrometer thickness and Golgi studies of the isocortex in juvenile neuronal ceroid-lipofuscinosis, morphologically proven by electron microscopy, revealed: 1. giant axonal dilatations of IIIab-pyramids. These expansions exceeded by far those found in pyramidal cell axons of other isocortical layers. 2. severe numerical reduction of neurons in the ganglionic layer.