Showing papers by "University of Bern published in 1977"
TL;DR: In this paper, it was shown that lepton number conservation, purely left-handed charged weak currents and vanishing neutrino masses are a limiting case of a parity symmetric SU2L × SUR × U2V gauge theory.
4,076 citations
TL;DR: A mathematical model of membrane action potentials of mammalian ventricular myocardial fibres is described, based as closely as possible on ionic currents which have been measured by the voltage‐clamp method.
Abstract: 1. A mathematical model of membrane action potentials of mammalian ventricular myocardial fibres is described. The reconstruction model is based as closely as possible on ionic currents which have been measured by the voltage-clamp method.2. Four individual components of ionic current were formulated mathematically in terms of Hodgkin-Huxley type equations. The model incorporates two voltage- and time-dependent inward currents, the excitatory inward sodium current, i(Na), and a secondary or slow inward current, i(s), primarily carried by calcium ions. A time-independent outward potassium current, i(K1), exhibiting inward-going rectification, and a voltage- and time-dependent outward current, i(x1), primarily carried by potassium ions, are further elements of the model.3. The i(Na) is primarily responsible for the rapid upstroke of the action potential, while the other current components determine the configuration of the plateau of the action potential and the re-polarization phase. The relative importance of inactivation of i(s) and of activation of i(x1) for termination of the plateau is evaluated by the model.4. Experimental phenomena like slow recovery of the sodium system from inactivation, frequency dependence of the action potential duration, all-or-nothing re-polarization, membrane oscillations are adequately described by the model.5. Possible inadequacies and shortcomings of the model are discussed.
1,414 citations
TL;DR: Results suggest that in platelets, as in muscle, cyclic AMP is a regulatory factor in the control of cytoplasmic calcium.
287 citations
TL;DR: The time span between the maximum of the initial signs and the beginning of recovery seemed to be particularly long in patients who showed residual signs on follow-up, and these patients also seemed frequently to have had a severe tetraparesis in the initial phase.
248 citations
TL;DR: The genetic maps of the fission yeast Schizosaccharomyces pombe were extended through the use of haploidization (spontaneous or induced by m-fluorophenylalanine), as well as by tetrad, random spore and mitotic analysis.
Abstract: The genetic maps of the fission yeast Schizosaccharomyces pombe were extended through the use of haploidization (spontaneous or induced by m-fluorophenylalanine), as well as by tetrad, random spore and mitotic analysis. A new diploidization method utilizing a meiosis-deficient mutant and improved haploidization techniques was employed. As a result of these and previous studies, 118 genetic markers have been assigned to 3 linkage groups. Centromere markers for all 3 chromosomes were identified and genetic maps containing a total of 71 genes were constructed. Our experiments indicate that 3 is very likely to be the haploid chromosome number of S. pombe .
232 citations
TL;DR: Isotope measurements on two adjacent cores through the Devon Island ice cap provide a well-dated climatic record for the past 5000 yr as discussed by the authors, which helps to separate climatic changes from changes in ice thickness or flow pattern.
Abstract: Isotope measurements on two adjacent cores through the Devon Island ice cap provide a well-dated climatic record for the past 5000 yr. Fluctuations in annual values include much ‘noise’, and ice flow over a rough bed produces distortions in the lowest 5% of core which covers roughly 120,000 yr. Comparison with the Camp Century, Greenland, record helps to separate climatic changes from changes in ice thickness or flow pattern.
199 citations
TL;DR: Intraoral radiographs are a valuable adjunct for the periodontal diagnosis and the diagnosis of trauma from occlusion and with standardized systems, radiographs may furnish additional quantitative data in clinical research.
Abstract: Intraoral radiographs are widely used in periodontal diagnosis and research. However, accurate radiographic interpretation is only possible with high quality images. Some of the technical and geometric variables to consider have been presented. Early periodontal lesions are not detected in radiographs. The amount of periodontal destruction in more advanced disease is generally underestimated. The accurate topography of periodontal pockets and the buccal and lingual aspects of the teeth cannot be visualized. Clinical probing is therefore a prerequisite for a complete periodontal diagnosis. However, radiographs are a valuable adjunct for the periodontal diagnosis and the diagnosis of trauma from occlusion. With standardized systems, radiographs may furnish additional quantitative data in clinical research.
168 citations
TL;DR: It is suggested that the various patterns of proliferation are merely morphologic variations of the same basic defect and nesidioblastosis may result from inappropriately controlled development of the endocrine pancreas that is not arrested but carries on beyond birth and during infancy.
Abstract: Seven surgical specimens of pancreas, obtained at laparotomy from infants suffering from persistent hyperinsulinemic hypoglycemia, were analyzed by qualitative and quantitative immunocytochemistry and by electron microscopy In five cases a multifocal ductuloinsular proliferation, in one a focal adenomatosis, and in one a solitary encapsulated nodule (adenoma) were observed Combinations of the different patterns of proliferation were seen in six cases Budding off from the ductular epithelium and interposition of endocrine cells between ductular epithelial cells were prominent features common to all cases An almost fivefold increase of the mean total area occupied by endocrine tissue was found over that of age-matched controls Four cell types were seen to participate regularly in the proliferation, and their ratios were remarkably constant in all cases, mean figures being 62:21:9:8 per cent for B:A:D:D 1 cells, respectively The ratio of B cells per total endocrine area in nesidioblastosis was very close to that per islet of the controls (62:59 per cent) Since common features were found in all or in the majority of cases, it is suggested that the various patterns of proliferation are merely morphologic variations of the same basic defect Nesidioblastosis may result from inappropriately controlled development of the endocrine pancreas that is not arrested but carries on beyond birth and during infancy The application of specific immunocytochemistry as a necessity for full appreciation of the extent of endocrine proliferation is stressed
143 citations
TL;DR: The major platelet membrane glycoproteins have been solubilized in 1.0% sodium deoxycholate and subjected to affinity chromatography on the lectins from Lens culinaris, wheat germ and Abrus precatorius to allow the distinction of at least seven separate glycoprotein entities.
124 citations
TL;DR: Two groups of patients with either low (osteoporosis), or high (Paget's disease), bone turnover were studied before and after sodium fluoride (NaF) and diphosphonate (EHDP) treatment, respectively, and correlations were not possible to draw any conclusions regarding the absolute "true" value of bone formation.
Abstract: The extent to which histomorphometric analysis of bone biopsies correlates with Ca kinetic and biochemical parameters to reflect true bone formation and resorption in adult man remains an unsolved issue. Two groups of patients with either low (osteoporosis), ( n = 15) or high (Paget's disease, n = 6) bone turnover were studied before and after sodium fluoride (NaF) and diphosphonate (EHDP) treatment, respectively. Histomorphometry of iliac crest biopsies permitted precise quantitation of the osteoblast layers (S Vob ), osteoid seams (S Vos ), the number of osteoclasts (N Aocl ) and the Howship's lacunae (S Vhl ). These determinations were correlated with serum alkaline phosphatase (aPh), urinary hydroxyproline (HyPro), Ca accretion rate (Vo + ), and Ca mobilization rate (Vo − ). In both patient groups bone formation indices were significantly correlated: S Vob Vo + , r = 0.85; S Vos Vo + , r = 0.83; and aPh Vo + , r = 0.97. Provided that bone matrix formation and mineralization progress at the same rate, bone formation may be assessed by measuring either aPh, Vo + , S Vob , or S Vos . From these correlations it is not possible to draw any conclusions regarding the absolute “true” value of bone formation, be it in terms of Ca kinetics, alkaline phosphatase, or histomorphometry. However, since Vo + retains its proportionality to all the other bone formation parameters tested, the so-called “slow exchange”, which refers to pure physicochemical Ca exchange processes in the bone mineral, does not perturb Vo + in an unsystematic way. Vo + as well as aPh and histomorphometric indices are thus reliable, though not absolute indices of bone formation. Bone resorption indices correlated less well than bone formation indices: N Aocl Vo − , r = 0.68 and S Vhl Vo − , r = 0.63 with both groups. In the osteoporotic group, a negative correlation existed between the empty Howship's lacunae S Vhe and Vo + , r = −0.62. Consequently, the overall extent of Howship's lacunae S Vhl is influenced both by bone resorption and bone formation. On the other hand, the best correlation of HyPro was with the sum of Vo + and Vo − , r = 0.97, confirming that HyPro is a sensitive index for the change of bone turnover.
118 citations
TL;DR: The results suggest that in the isolated membranes small amounts of phosphatidylcholine can be incorporated into an additional region which is unavailable for the membrane lecithinase.
TL;DR: Evidence is presented suggesting that genes of higher eukaryotes correspond to much larger DNA segments than in microorganisms, and may well be restricted to small regions of the genome, possibly corresponding to the structural genes.
Abstract: THE size of the eukaryotic genome increases with the evolutionary complexity of the organism, although this relation is somewhat obscured by large differences in the haploid DNA content of closely related species Yet the total number of genes is believed to be fairly constant, suggesting that genes of higher eukaryotes correspond to much larger DNA segments than in microorganisms1 In that case, only a small fraction of each gene would code for the ultimate gene product, the remainder being ‘spacer’ DNA with still ill-defined functions The sequence coding for the gene product will be hereafter designated as the structural gene The complex organisation of chromatine in higher organisms raises the problem of its possible influence on the distribution of recombination events I shall present here evidence suggesting that they may well be restricted to small regions of the genome, possibly corresponding to the structural genes
TL;DR: In this article, a cw dye laser is tuned over the B, A, X transitions of Na 2 /K 2 while a second laser or a high pressure lamp ionizes the excited states.
TL;DR: The haemolymph of winter bees in contrast to that of summer bees has a low juvenile hormone titre and a high protein titre, suggesting that the winter bee physiology may be brought about by low JH-production.
Abstract: The haemolymph of winter bees (long life span) in contrast to that of summer bees (short life span) has a low juvenile hormone titre and a high protein titre. It is suggested that the winter bee physiology may be brought about by low JH-production.
TL;DR: There is evidence that during later phase of primary stimulation (day 3–13), the increase in synthesis of vitellogenin cannot be attributed anymore to a significant accumulation ofvitellagenin mRNA, which implies that there is a coincidence between appearance and extent of synthesis ofViteLLogenin and the abundance of vITEllogen in mRNA in the cytoplasm.
TL;DR: It is proposed that a function of the alkaline phosphatase of matrix vesicles in vivo is to hydrolyze the substrates PPi, ADP, and ATP, which are known inhibitors of calcium phosphate precipitation.
Abstract: Some of the characteristics of the pyrophosphatase and ATPase activities studied in isolated cartilage matrix vesicles were found to be similar to those already reported for the solubilized and purified bone alkaline phosphatase. Thus, the pH optimum of the pyrophosphatase activity responded similarly to changes in the concentration of Mg2+, Ca2+, and PPi. Further, the ATPase activity was not activated by Ca2+ in the presence of an optimal Mg2+ concentration. It is proposed that a function of the alkaline phosphatase of matrix vesicles in vivo is to hydrolyze the substrates PPi, ADP, and ATP, which are known inhibitors of calcium phosphate precipitation.
TL;DR: It is concluded that only the glycerophospholipids in the human erythrocyte membrane are involved in the maintenance of the (Ca2+ + Mg2+)-ATPase activity, and in particular that fraction of these phospholipid fraction located in the inner half of the membrane.
TL;DR: A vesicular fraction obtained from homogenized platelets indeed accumulates Ca actively; this Ca-pump is stimulated by cyclic AMP and protein kinase; it may be involved in the recovery of platelets after activation.
Abstract: The increase of the cytoplasmic Ca-concentration plays a central role in the initiation of platelet activation. Four kinds of movements of Ca-ions are presumed to occur during this process: a) Ca-ions liberated from membranes induce the rapid shape change. b) Vesicular organelles release Ca-ions into the cytoplasm which initiate the release reaction. c) The storage organelles called dense bodies, secrete their contents including Ca-ions to the outside during the release reaction. d) At the same time a rearrangement of the plasma membrane occurs, resulting in an increase in its permeability for Ca-ions as well as in an increase in the number of Ca-binding sites. Since most processes occurring during platelet activation are reversible, the platelet must be equipped with a mechanism which removes Ca-ions from the cytoplasm. A vesicular fraction obtained from homogenized platelets indeed accumulates Ca actively. This Ca-pump is stimulated by cyclic AMP and protein kinase; it may be involved in the recovery of platelets after activation.
TL;DR: Using experimental pain models reliable results are not to be expected as anxiety fluctuates intra‐ and interindividually in an unpredictable and uncontrollable manner.
Abstract: A study was made of a number of factors that might be responsible for the unreliable results obtained in experimentally induced pain in man. In a randomised, double-blind, cross-over study on 32 healthy, male volunteers, the ischaemic pain test [14] and several psychological tests were performed. The influence of the following factors on the pain test results were examined: (a) ingestion of single, oral doses of 1000 mg aspirin (ASA) and placebo, (b) practice effect, (c) initial pain sensitivity, (d) anxiety, coping behaviour, attitude to the experiment and personality factors. The analgesic activity of ASA could not be demonstrated. An interaction between primary pain sensitivity and the sequence of drug administration was found. Furthermore, anxiety had a marked influence on the test results. Using experimental pain models reliable results are not to be expected as anxiety fluctuates intra- and interindividually in an unpredictable and uncontrollable manner.
TL;DR: The Planck mass arises spontaneously through the coupling of gravity to a system of scalar fields, in a scale invariant way as mentioned in this paper, and the same scalars generate all masses of leptons, quarks and vector bosons responsible for the matter interactions in the limit of weak gravitational fields.
TL;DR: The History of Drug Metabolism: Discoveries of the major Pathways in the 19th Century as mentioned in this paper... is a history of drug metabolism from the early 19th century to the present.
Abstract: (1977). History of Drug Metabolism: Discoveries of the Major Pathways in the 19th Century. Drug Metabolism Reviews: Vol. 6, No. 1, pp. 1-50.
TL;DR: The anomalous g −factor a ≡ ( g −2)/2 has been measured for muons of both charges in the Muon Storage Ring at CERN as mentioned in this paper, which is very close to the most recent theoretical prediction 1165921(10) × 10 −9.
TL;DR: It is concluded from the present study that the rested- state contraction may be regulated primarily by Ca ions flowing into the cell during the action potential, while the stimulated steady-state contraction seems to be determined by the amount of Ca ions released from the sarcoplasmic reticulum.
Abstract: In this study simultaneous measurements of action potentials and force of contraction of isolated ventricular muscle from cat and calf hearts were performed under stimulated steady-state and rested-state conditions. It is shown that time-to-peak force of the rested-state contraction correlates well with electrically induced changes in the duration of the platcau phase of the corresponding action potential. Moreover, adrenaline (0.2 and 0.6 μM) and theophylline (2 and 5 mM) increase the amplitude of the rested-state and stimulated steady-state contractions. The concentrations of these drugs were about equi-effective in increasing stimulated steady-state force of contraction. However, the effect of adrenaline on the rested-state contraction is small in comparison to that of theophylline. The effect of both drugs on the rested-state contraction is accompanied by an increase in the plateau amplitude of the corresponding action potential. Since the plateau phase of the cardiac action potential is maintained by the slow inward current mainly carried by Ca ions and since adrenaline and methylxanthines increase this current, it is concluded from the present study that the rested-state contraction may be regulated primarily by Ca ions flowing into the cell during the action potential, while the stimulated steady-state contraction seems to be determined by the amount of Ca ions released from the sarcoplasmic reticulum.
TL;DR: The duration of the compound sensory action potentials recorded from the median nerve at the wrist and elbow shows a negative temperature coefficient and the peak-to-peak amplitude of these potentials increases from 22° to approximately 26°C and then decreases progressively again up to 36°C.
Abstract: Sensory conduction velocities of normal subjects are increasing linearly with rising temperature. The duration of the compound sensory action potentials recorded from the median nerve at the wrist and elbow shows a negative temperature coefficient. The peak-to-peak amplitude of these potentials increases from 22° to approximately 26°C and then decreases progressively again up to 36°C. It is believed that this behavior is due to a combination of decreasing temporal dispersion, height and duration of the individual spike potentials.
TL;DR: The rapid FPA assay is thus of particular interest in those clinical emergencies associated with a low plasma fibrinogen and a negative ethanol test.
TL;DR: In this article, the cross-sections of photon-hadron scattering and hadron-Hadron scattering are calculated in terms of the quark and gluon distribution functions of hadrons.
TL;DR: The DNA coding for ribosomal RNA in Physarum polycephalum exists as a collection of extra-chromosomal molecules of molecular weight 37 X 10(6) and replicating molecules observed by electron microscopy are all linear.
Abstract: The DNA coding for ribosomal RNA in Physarum polycephalum exists as a collection of extra-chromosomal molecules of molecular weight 37 X 10(6). We have investigated the replication of rDNA, with the following results. (a) Replication of rDNA is unscheduled. This means that molecules that are replicated at any particular time in one mitotic cycle have an equal probability of replicating again in each time interval in the subsequent cycle. Similarly, in a single cycle, some molecules replicate more than once, and some not at all. (b) Replication forks appear to move bidirectionally from points 45% or 33% from one end of the DNA. Replicating molecules observed by electron microscopy are all linear.
TL;DR: In this article, the anisotropic rotation of perylene in paraffin is investigated by time-dependent fluorescence depolarization as a function of temperature between −20°C and +50°C.
TL;DR: Several systems capable of performing functions resembling human intellectual activity are commerically available; one, the OctopusTM, is described in detail.
TL;DR: In this paper, the electron temperature of plasma generated by 35psec 1.06-m laser pulses, focused onto perspex targets, has been measured as a function of laser polarization and incidence angle.
Abstract: The electron temperature of plasma generated by 35-psec 1.06-\ensuremath{\mu}m laser pulses, focused onto perspex targets, has been measured as a function of laser polarization and incidence angle. These measurements demonstrate that resonance absorption contributes significantly to the total absorption of obliquely incident laser radiation. The relative magnitudes of resonance and classical absorption have been measured together with the density of "hot electrons" heated by the resonance process.