Steroide und Fibroblastenwachstum

Summary To clarify the contradictory results concerning the influence of different corticosteroids on growth of fibroblasts, the rate proliferation ofl-cells under increasing doses of prednisolone and-methazone was studied by measuring³H-thymidine uptake. Growth was inhibited in a linear fashion by an increasing concentration of steroids.-methazone had a 10 times stronger effect compared with an equal quantity of prednisolone.

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Mit Unterstützung der Strebel-Stiftung Mannheim.     

Influence de l'anaérobiose et de différentes tensions d'oxygène sur la libération d'histamine dans la réaction anaphylactiquein vitro

Summary The influence of anaerobiose and of varied oxygen tensions upon respiration and histamine release during anaphylactic reaction in guineapig lung slicesin vitro was studied.No histamine was liberated in the absence of oxygen. With increasing oxygen tensions, increasing histamine quantities were released; these quantities reached the control values when the atmosphere contained 10% oxygen.These results indicate that the mechanism of histamine release in the anaphylactic reaction is linked with the aerobic metabolism of the cell.

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Boursicrs du Consclho Nacional de Pesquisas.     

Influence of host plant and larval diet on ovarian productivity inAcrolepiopsis assectella Z. (Lepidoptera: Acrolepiidae)

Summary Females ofAcrolepiopsis assectella, reared on a semi-synthetic diet and laying on artificial substrates, do not respond to external stimuli by increasing ovarian production. When returned to the natural host (Allium porrum) for only one generation, ovarian production again rises and reaches the same level as in wild females, but its variability is strongly reduced. We conclude that selection under artificial conditions eliminates individuals which strictly depend on host plants for stimulation of larval nutrition and of reproduction.     

Cross-resistance of trichomonads to 5-nitroimidazole-derivatives

Summary The strainT. foetus KV 1/M 100, a sub-strain ofT. foetus Kv 1, was made highly resistant to metronidazole by several passages in mice under increasing drug pressure. This drug resistance was accompained by a remarkable cross-resistance to all 5-nitroimidazole-derivatives tested in vitro and in vivo.     

Pollen carryover and neighbourhood inRanunculus bulbosus

The pattern of gene flow has a major influence on the spatial scale of evolutionary processes. In plant populations pollen carryover will influence the pattern of gene flow. InRanunculus bulbosus L. pollen carryover was found to occur over a maximum of 5 flowers, with seed set per flower decreasing in a curvilinear fashion with increasing visit number in a sequence of visits by a bee after pollen pick-up from a donor plant. The effect of pollen carryover is to increase both neighbourhood area and neighbourhood size by two-fold.     

Multiple prediction intervals for time series: Comparison of simultaneous and marginal intervals

Simultaneous prediction intervals for forecasts from time series models that contain L (L ≤ 1) unknown future observations with a specified probability are derived. Our simultaneous intervals are based on two types of probability inequalities, i.e. the Bonferroni- and product-types. These differ from the marginal intervals in that they take into account the correlation structure between the forecast errors. For the forecasting methods commonly used with seasonal time series data, we show how to construct forecast error correlations and evaluate, using an example, the simultaneous and marginal prediction intervals. For all the methods, the simultaneous intervals are accurate with the accuracy increasing with the use of higher-order probability inequalities, whereas the marginal intervals are far too short in every case. Also, when L is greater than the seasonal period, the simultaneous intervals based on improved probability inequalities will be most accurate.     

Short‐Term Forecasts of French GDP: A Dynamic Factor Model with Targeted Predictors

In recent years, factor models have received increasing attention from both econometricians and practitioners in the forecasting of macroeconomic variables. In this context, Bai and Ng (Journal of Econometrics 2008; 146 : 304–317) find an improvement in selecting indicators according to the forecast variable prior to factor estimation (targeted predictors). In particular, they propose using the LARS‐EN algorithm to remove irrelevant predictors. In this paper, we adapt the Bai and Ng procedure to a setup in which data releases are delayed and staggered. In the pre‐selection step, we replace actual data with estimates obtained on the basis of past information, where the structure of the available information replicates the one a forecaster would face in real time. We estimate on the reduced dataset the dynamic factor model of Giannone et al. (Journal of Monetary Economics 2008; 55 : 665–676) and Doz et al. (Journal of Econometrics 2011; 164 : 188–205), which is particularly suitable for the very short‐term forecast of GDP. A pseudo real‐time evaluation on French data shows the potential of our approach. Copyright © 2013 John Wiley & Sons, Ltd.     

When a theory of aging ages badly

According to the widely acknowledged mitochondrial free radical theory of aging (MFRTA), the macromolecular damage that results from the production of toxic reactive oxygen species (ROS) during cellular respiration is the cause of aging. However, although it is clear that oxidative damage increases during aging, the fundamental question regarding whether mitochondrial oxidative stress is in any way causal to the aging process remains unresolved. An increasing number of studies on long-lived vertebrate species, mutants and transgenic animals have seriously challenged the pervasive MFRTA. Here, we describe some of these new results, including those pertaining to the phenotype of the long-lived Mclk1 ^+/− mice, which appear irreconcilable with the MFRTA. Thus, we believe that it is reasonable to now consider the MFRTA as refuted and that it is time to use the insight gained by many years of testing this theory to develop new views as to the physiological causes of aging.     

Judgemental revision of sales forecasts: The relative performance of judgementally revised versus non-revised forecasts

The judgemental revision of sales forecasts is an issue which is receiving increasing attention in the forecasting literature. This paper compares the performance of forecasts after revision by managers with that of the forecasts which were accepted by them without revision. The data set consists of sales forecasting data from an industrial company, spanning six quarterly periods and relating to some 900 individual products. The findings show that, in general, the improvements made by managers bring the forecast errors of revised forecasts more into line with non-revised forecasts, but the change is often marginal, and the best result is equivalence between revised and non-revised forecasts.     

Regulation of cross-bridge detachment by Ca ions at high ionic strength in molluscan catch muscle

Summary Changes in the profile of equatorial intensities of X-ray diffraction from an intact, anterior byssal retractor muscle (ABRM) ofMytilus were examined at rest, during contracture brought about by acetylcholine (ACh) and a subsequent rigor-like contraction caused by raising the tonicity of the external solution, and after returning the tonicity to normal. The results suggest that the cross-bridges formed between thick and thin actin filaments during the ACh-contracture were maintained in the hypertonic solution and broken on decreasing the tonicity before the recovery of spacing of the actin filament lattice. A similar rigor-like contraction was induced in glycerinated ABRM by increasing salt concentration during active contraction. The rigor-like force declined rapidly when Ca⁺⁺ concentration decreased. The results suggest that the detachment of the cross-bridge from the actin filament is regulated by Ca⁺⁺ at high ionic strength in the ABRM.     

Mean cytoplasmic protein concentration of host erythrocytes and the reticulocyte response inPlasmodium berghei infected mice

Summary the decreasing mean cytoplasmic protein concentration (MPC) ofP. berghei host cells is paralled by an increasing parasitemia and percent reticulocyte response. The reticulocyte response parallels the percent parasitemia except during a period of accelerated reticulocytosis noted during the midpoint of the infection at which time the percent reticulocytes increases at a rate more than double the rate of increase of percent parasitemia. Although the reticulocyte population and the host cell population are usually equivalent, the disparity noted suggests the existence of unique characteristics in the reticulocyte response ofP. berghei infected mice.     

δ-Opioid receptors protect from anoxic disruption of Na+ homeostasis via Na+ channel regulation

Hypoxic/ischemic disruption of ionic homeostasis is a critical trigger of neuronal injury/death in the brain. There is, however, no promising strategy against such pathophysiologic change to protect the brain from hypoxic/ischemic injury. Here, we present a novel finding that activation of δ-opioid receptors (DOR) reduced anoxic Na⁺ influx in the mouse cortex, which was completely blocked by DOR antagonism with naltrindole. Furthermore, we co-expressed DOR and Na⁺ channels in Xenopus oocytes and showed that DOR expression and activation indeed play an inhibitory role in Na⁺ channel regulation by decreasing the amplitude of sodium currents and increasing activation threshold of Na⁺ channels. Our results suggest that DOR protects from anoxic disruption of Na⁺ homeostasis via Na⁺ channel regulation. These data may potentially have significant impacts on understanding the intrinsic mechanism of neuronal responses to stress and provide clues for better solutions of hypoxic/ischemic encephalopathy, and for the exploration of acupuncture mechanism since acupuncture activates opioid system.     

Kepler,Tycho, and the ‘Optical Part of Astronomy’: the genesis of Kepler's theory of pinhole images

In the last half of the 16^th century, the method of casting a solar image through an aperture onto a screen for the purposes of observing the sun and its eclipses came into increasing use among professional astronomers. In particular, Tycho Brahe adapted most of his instruments to solar observations, both of positions and of apparent diameters, by fitting the upper pinnule of his diopters with an aperture and allowing the lower pinnule with an engraved centering circle to serve as a screen. In conjunction with these innovations a method of calculating apparent solar diameters on the basis of the measured size of the image was developed, but the method was almost entirely empirically based and developed without the assistance of an adequate theory of the formation of images behind small apertures. Thus resulted the unsuccessful extension of the method by Tycho to the quantitative observation of apparent lunar diameters during solar eclipses. Kepler's attention to the eclipse of July 1600, prompted by Tycho's anomalous results, gave him occasion to consider the relevant theory of measurement. The result was a fully articulated account of pinhole images. Dedicated to the memory of Ronald Cameron Riddell (29.1.1938–11.1.1981)     

Sonnenflecken und ihre terrestrischen Wirkungen

Summary After a discussion of the 11-year solar-cycle as regarded from the standpoint of the eruption-hypothesis, which offers a possibility to predict the solar activity for several years and after a review of the magnetic properties of the sun and the sunspots, the paper deals with the new theories of the spots and the solar-cycle as suggested byAlfvén andWalén.The terrestrial effects of the phenomena associated with the solar cycle are classified into 4 groups: effects produced by a) a wave radiationW _k emitted continuously by the sun, b) a wave radiationW _e emitted from the chromospheric eruptions, c) a particle radiationP _k emitted by the so-called M-regions, and d) a particle radiationP _e ejected from the eruptions. The connection between the solar eruptions and the radiationsP _e ,W _e is a well established fact; on the other hand the radiationsW _k ,P _k could be connected by the author with the solar corona and the stationary solar prominences respectively.To account for the intensity of theW _k -radiation a temperature of the solar corona of one million degree is required in agreement with the observed temperature. The heating of the corona occurs in the electric field around an increasing sunspot. As in the corona the mean free path amounts to several kilometers, particles may be accelerated up to 1000 eV, so far the conditionh=0 is fulfilled. Generally speaking acceleration is possible only in such regions whereh andh are not perpendicular to each other.     

Stimulation of sporulation ofClostridium perfringens by papaverine

Summary Papaverine induced sporulation inClostridium perfringens, strains FD-1 and PS52; growth was markedly slowed under these conditions. Papaverine induced sporulation in the presence of glucose, a sporulation repressor, although increasing glucose concentrations overcame the papaverine effect. Papaverine induced sporulation of strain FD-1 more effectively than did theophylline.The author wishes to thank Mrs P.A. Thompson for excellent technical assistance.     

The Penicillium chrysogenum antifungal protein PAF, a promising tool for the development of new antifungal therapies and fungal cell biology studies

In recent years the interest in antimicrobial proteins and peptides and their mode of action has been rapidly increasing due to their potential to prevent and combat microbial infections in all areas of life. A detailed knowledge about the function of such proteins is the most important requirement to consider them for future application. Our research in recent years has been focused on the low molecular weight, cysteine-rich and cationic antifungal protein PAF from Penicillium chrysogenum, which inhibits the growth of opportunistic zoo-pathogens including Aspergillus fumigatus, numerous plant-pathogenic fungi and the model organism Aspergillus nidulans. So far, the experimental results indicate that PAF elicits hyperpolarization of the plasma membrane and the activation of ion channels, followed by an increase in reactive oxygen species in the cell and the induction of an apoptosis-like phenotype. Detailed knowledge about the molecular mechanism of action of antifungal proteins such as PAF contributes to the development of new antimicrobial strategies that are urgently needed. Received 09 August 2007; received after revision 17 September 2007; accepted 19 September 2007     

Passaggio di nucleoli attraverso la membrana nucleare negli ovociti in accrescimento diPatella coerulea L. (Moll. Gast. Pros.)

Summary The author has found in increasing ovocytes ofPatella coerulea, particularly in the nuclear membrane, a real passage of small nucleoli from the nucleus to the cytoplasm. Thus not all the nucleoli which appear little by little in the nucleus are amphinucleoli.