Strong and deep Atlantic meridional overturning circulation during the last glacial cycle.

Extreme, abrupt Northern Hemisphere climate oscillations during the last glacial cycle (140,000 years ago to present) were modulated by changes in ocean circulation and atmospheric forcing. However, the variability of the Atlantic meridional overturning circulation (AMOC), which has a role in controlling heat transport from low to high latitudes and in ocean CO2 storage, is still poorly constrained beyond the Last Glacial Maximum. Here we show that a deep and vigorous overturning circulation mode has persisted for most of the last glacial cycle, dominating ocean circulation in the Atlantic, whereas a shallower glacial mode with southern-sourced waters filling the deep western North Atlantic prevailed during glacial maxima. Our results are based on a reconstruction of both the strength and the direction of the AMOC during the last glacial cycle from a highly resolved marine sedimentary record in the deep western North Atlantic. Parallel measurements of two independent chemical water tracers (the isotope ratios of (231)Pa/(230)Th and (143)Nd/(144)Nd), which are not directly affected by changes in the global cycle, reveal consistent responses of the AMOC during the last two glacial terminations. Any significant deviations from this configuration, resulting in slowdowns of the AMOC, were restricted to centennial-scale excursions during catastrophic iceberg discharges of the Heinrich stadials. Severe and multicentennial weakening of North Atlantic Deep Water formation occurred only during Heinrich stadials close to glacial maxima with increased ice coverage, probably as a result of increased fresh-water input. In contrast, the AMOC was relatively insensitive to submillennial meltwater pulses during warmer climate states, and an active AMOC prevailed during Dansgaard-Oeschger interstadials (Greenland warm periods).

[Mucormycosis due to Mycocladus corymbiferus in a fattening pig]. / Mucormykose durch Mycocladus corymbiferus bei einem Mastschwein.

A fattening pig with enlarged head and abdominal lymph nodes was examined. An aspirate of the abscesses did not produce a conclusive diagnosis. Only an excision with subsequent histological and bacteriological examination showed the mould Mycocladus corymbiferus (syn. Absidia corymbifera) to be present. Similar abscesses should be examined as actinomycosis and leucosis are the main differential diagnoses.

Forest fertilization with wood ash: effect on the distribution and storage of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs).

Before wood ash can be safely used as a fertilizer in forests, possible negative effects such as input of organic contaminants or remobilization of contaminants already stored in the soil must be investigated. The objective of this study was to examine the effects of wood ash application on concentrations, storage, and distribution of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in a Swiss forest soil. In May 1998, we added 8 Mg wood ash ha(-1) to a forest soil. We determined 20 PAHs and 14 PCBs in the organic layer, in the bulk mineral soil, and in soil material taken from preferential flow paths and from the matrix before and after the wood ash application. In the control plots, the concentrations of PAHs in the organic layer indicated moderate pollution (sum of 20 PAHs: 0.8-1.6 mg kg(-1)), but sum of PCB concentrations was high (21-48 microLg kg(-1)). The wood ash had high concentrations of PAHs (sum of 20 PAHs: 16.8 mg kg(-1)), but low concentrations of PCBs (sum of 14 PCBs: 3.4 microg kg(-1)). The wood ash application increased the PAH concentrations in the organic horizons up to sixfold. In contrast, PCB concentrations did not change in the Oa horizon and decreased up to one third in the Oi and Oe horizons. The decrease was probably caused by the mobilization of stored PCBs because of the high pH of the wood ash. This probably results in a higher mobility of dissolved organic matter, acting as PCB carrier. In the mineral soil, the preferential flow paths of the A horizon contained more PAHs and PCBs (+20 +/- 15% and +43 +/- 60%, respectively) than the matrix. This was particularly true for higher molecular weight compounds (molecular weight > 200 g mol(-1)). Below 50 cm depth, concentrations of PAHs and PCBs were smaller in the preferential flow paths, suggesting that in deeper depths, processes acting as sinks dominated over inputs in the preferential flow paths.

Comparison between standard radiography and spiral CT with 3D reconstruction in the evaluation, classification and management of tibial plateau fractures.

The aim of this study was to compare the diagnostic efficiency of plain film and spiral CT examinations with 3D reconstructions of 42 tibial plateau fractures and to assess the accuracy of these two techniques in the pre-operative surgical plan in 22 cases. Forty-two tibial plateau fractures were examined with plain film (anteroposterior, lateral, two obliques) and spiral CT with surface-shaded-display 3D reconstructions. The Swiss AO-ASIF classification system of bone fracture from Muller was used. In 22 cases the surgical plans and the sequence of reconstruction of the fragments were prospectively determined with both techniques, successively, and then correlated with the surgical reports and post-operative plain film. The fractures were underestimated with plain film in 18 of 42 cases (43%). Due to the spiral CT 3D reconstructions, and precise pre-operative information, the surgical plans based on plain film were modified and adjusted in 13 cases among 22 (59%). Spiral CT 3D reconstructions give a better and more accurate demonstration of the tibial plateau fracture and allows a more precise pre-operative surgical plan.

Critical examination of trace element enrichments and depletions in soils: As, Cr, Cu, Ni, Pb, and Zn in Swiss forest soils.

The aim of this study was to obtain an overview of trace element concentrations in Swiss forest soils and to critically assess the measured values with respect to anthropogenic input vs. lithogenic background. Twenty-three sites were selected which represent a broad range of natural forest sites, bedrock material and soil types of Switzerland. At each site, samples were collected from all genetic soil horizons down to a C or B/C horizon. Total concentrations of As, Cr, Cu, Ni, Pb, and Zn in all samples were determined by X-ray fluorescence spectrometry. There were distinct differences in the geological background values estimated from the concentrations measured in the samples from the lowest soil horizon. Background concentrations for Cr and Ni were lowest in granite and gneiss, whereas Pb and Zn were highest in limestone and marl. Enrichment or depletion of the trace elements was assessed using Zr as reference element. Within the same profile, the six trace elements showed completely different enrichment/depletion patterns with depth. The various natural processes and anthropogenic inputs that can lead to these patterns are critically discussed. Based on this critical assessment, pollution of the investigated forest soils was found to be most severe for Pb and Zn and to a somewhat lesser extent for As and Cu, whereas anthropogenic input of Cr and Ni seems to be less important. The data suggest that a critical evaluation of enrichment factors is a better tool to assess soil pollution with trace elements than the use of maximum allowable concentrations (MAC) for topsoil samples. The enrichment factors calculated as described here consider the effects of geological variation on metal abundances whereas the MAC does not. In order to obtain an estimate of soil solution concentrations, water extracts of the samples collected from a subset of 10 soil profiles were analyzed for the same trace elements. Solubility of all elements generally decreased with soil depth. An exception was Cr, Cu, and Ni solubility in the humus layer, which was lower than in the underlying mineral horizon. For all elements, solubility was higher for the collective of soil samples depleted in this element when compared to the samples, in which the element was enriched.

A new approach for quantifying cumulative, anthropogenic, atmospheric lead deposition using peat cores from bogs: Pb in eight Swiss peat bog profiles.

Peat cores taken from eight Swiss peatlands were used to calculate inventories of anthropogenic Pb using either Sc or Zr to quantify Pb derived from rock weathering. The shapes of the Pb/Sc and Pb/Zr profiles suggest that Pb was supplied exclusively by atmospheric deposition at all sites. At one of the sites (Etang de la Gruère), anthropogenic Pb was calculated using both Sc and Zr as the conservative reference element. Lithogenic Pb determined using Sc was twice that obtained using Zr, possibly because Zr resides only in zircons which are dense compared to pyroxene and amphibole which are the main Sc-bearing phases in the earth's crust. However, the inventory of 'natural' Pb (supplied almost entirely by soil dust) is dwarfed by the anthropogenic inventory such that anthropogenic Pb calculated using Sc and Zr agree to within 5%. The total amount of anthropogenic Pb accumulated in the bogs was calculated by simply adding the mass of anthropogenic Pb for each peat slice over the length of each core. Cumulative, anthropogenic Pb calculated in this way ranged from 1.0 to 9.7 g/m2 and showed pronounced regional differences: the site south of the Alps (Gola di Lago in Canton Ticino) with direct exposure to the heavily industrialized region of northern Italy received nearly 10 times more anthropogenic Pb as the sites in more remote alpine regions (Schöpfenwaldmoor in Canton Berne, and Mauntschas in Canton Grisons). The approach used here to calculate cumulative, anthropogenic, atmospheric Pb (CAAPb) is simple and robust, independent of the chronology of Pb deposition, and makes no assumptions about the immobility of Pb within the peat profile. Given the worldwide distribution of peat bogs, it should be possible to undertake continental and global inventories of atmospheric metal deposition, for both the natural and anthropogenic components of most trace metals of environmental interest.

[Value of 3D CT in diagnosis and treatment of fractures of the tibial plateau]. / Apport du CT-3D dans le diagnostic et le traitement des fractures des plateaux tibiaux.

A precise classification and an optimal understanding of tibial plateau fractures are the basis of a conservative treatment or adequate surgery. The aim of this prospective study is to determine the contribution of 3D CT to the classification of fractures (comparison with standard X-rays) and as an aid to the surgeon in preoperative planning and surgical reconstruction. Between November 1994 and July 1996, 20 patients presenting 22 tibial plateau fractures were considered in this study. They all underwent surgical treatment. The fractures were classified according to the Müller AO classification. They were all investigated by means of standard X-rays (AP, profile, oblique) and the 3D CT. Analysis of the results has shown the superiority of 3D CT in the planning (easier and more acute), in the classification (more precise), and in the exact assessment of the lesions (quantity of fragments); thereby proving to be of undeniable value of the surgeon.

Equilibrium ion exchange method: methodology at low ionic strength and copper(II) complexation by dissolved organic matter in a leaf litter extract.

The equilibrium ion exchange method (EIM) is a powerful tool for the investigation of metal cation complexation by dissolved organic matter (DOM) in natural systems. Tests with different ion exchange resins demonstrated that under low ionic strength conditions (0.01 mol/kg) and in the presence of DOM, equilibration times of at least 24 h are required for experiments with Cu(II). The classical approach to the EIM was modified by using nonlinear reference adsorption isotherms in order to expand the method to a broader range of experimental conditions. For Cu(II) at low ionic strength (0.01 mol/kg), the reference isotherms between pH 4 and 6 were identical and were mathematically modeled in terms of Langmuir adsorption parameters. The EIM using nonlinear reference isotherms was validated between pH 4 and 6 by the correct determination of the stability constants for the complexes CuOxalate and Cu(Oxalate)(2). Then the method was used to quantitatively characterize the Cu(II) complexation behavior of DOM in an aqueous chestnut leaf litter extract between pH 4 and 6. In contrast to the classical approach to the EIM, data were analyzed by using plots [Cu](bound)/[Cu](free)vs. [Cu](bound). This allowed the determination of both, conditional stability constants and metal binding capacities for two different binding site classes. The logarithmic values of the stability constants were about 8 for the strong binding sites and 5.5-6 for the weak binding sites. The total Cu(II) binding capacity increased from 0.22 mol/(kg C) at pH 4 to 2.85 mol/(kg C) at pH 6.

Toxicity and mutagenicity of anthraquinones from Aspergillus chevalieri.

More than 100 strains of the Aspergillus glaucus group were cultivated on synthetic media for 11 days at 28 degrees C. Organic extracts of fungal material were screened by thin-layer chromatography (TLC) for the mycotoxins aflatoxins B1,2 and G1,2, sterigmatocystin, ochratoxin A, gliotoxin, patulin, and xanthocillin X. None of these toxins were produced in detectable amounts under experimental conditions. Nevertheless, organic extracts exhibited high toxicity after intraperitoneal (i.p.) administration in mice. Aspergillus chevalieri strain ZT 8268 was selected for further investigation of its toxic metabolites. The main toxic action was attributed to the four anthraquinone derivatives, physicion, physcionanthrone B, physciondianthrone, and erythroglaucin, which were isolated and identified. No toxic effects were found after oral administration. Using the Salmonella/mammalian microsome test, mutagenic activity (frame-shift) was detected in strain TA 1537 in the presence of S-9 liver microsome preparation.

Timing of neuronal death following successive blockade of protein synthesis and axoplasmic transport in the axonal target territory.

Neurons in the isthmo-optic nucleus (ION) of chick embryos can withstand a substantial cycloheximide-induced reduction in protein synthesis in their target territory, the retina, at the very time when their survival is known to depend on a retrograde signal from the latter. We here test the hypothesis that this resistance to the cycloheximide injection might be due to the accumulation in the ION of a reserve of retina-derived trophic molecules (or of resulting second messengers). Following an intraocular injection of cycloheximide at E15 to deplete the hypothetical reserve in one ION, both eyes received injections of colchicine (which blocks axoplasmic transport) at E16. The resulting time course of cell death was very similar in the two IONs, which refutes the hypothesis. The most plausible alternative is that there is a reserve of trophic substance in the retina capable of maintaining the ION for about 1 day.

Limits to the dependence of developing neurons on protein synthesis in their axonal target territory.

Our basic question was whether the survival of developing neurons is critically dependent on the level of protein synthesis in the axonal target region. The experiments were carried out on the projection from the isthmo-optic nucleus (ION) to the contralateral retina in chick embryos. The ION is known to undergo almost 60% neuronal death between embryonic days (E) 12 and E17 and to be critically dependent on the retina for trophic support throughout this period and shortly afterwards. Various concentrations of the protein synthesis inhibitor cycloheximide were infused into one eye from E15 to E19. Moderate inhibition (up to about 40%) of retinal protein synthesis, which did not lead to retinal degeneration, had no detectable effects on the number of neurons, nor on the general morphology, in the ION. Only when the inhibition was as high as 50%, leading to widespread degeneration in the retina, did massive degeneration occur also in the ION. It was also shown that a single intraocular injection of cycloheximide at E15 that inhibited retinal protein synthesis by as much as 70-90% during the subsequent 24 h had little effect on the ION in embryos fixed at E19. These results indicate that although the ION neurons are critically dependent on the retina, they can resist major reductions in the level of retinal protein synthesis, which argues against the widespread belief that neuronal survival during development is regulated by the limited production of trophic molecules in the axonal target area. The data are, however, compatible with alternative hypotheses. Most plausibly, survival may be regulated by limited access to a nonlimiting supply of trophic molecules.

Retrograde modulation of dendritic geometry in the vertebrate brain during development.

The neurons of the chick's isthmo-optic nucleus (ION) are known to innervate the retina. We here show that removing the retinal primordia causes the ION dendritic trees to be much less polarized than normal. Our observations were made at 11 embryonic days, which is before the isthmo-optic neurons become dependent on the retina for survival. Other parameters such as neuronal size were unchanged, so the effect seems to have been specific to dendritic shape. Our interpretation is that early target removal eliminates a retrograde signal that normally enhances dendritic polarization.

[Comparison of methods for the quantitative detection of moulds in foods. III. Comparison of different culture media for the mould plate count (author's transl)]. / Vergleichende Untersuchungen zur quantitativen Erfassung des Schimmelpilzbefalls bei Lebensmitteln. III. Vergleich verschiedener Nährmedien zur kulturellen Koloniezahlbestimmung.

The mould plate count and taxonomical grouping of the mould flora of 9 moulded non-fluid foods were compared on totally 12 different media, which are commonly used for the detection of moulds.--In contrary to the bacteriological practice, moulds should only be counted on plates with 20-50 colonies, as on plates covered densely with a mixed mould flora, simple colonies are often no more detectable. Mould plate counts of all tested products were in the same range on all media with a sugar content of 1-2% (dextrose, maltose). With fruits and vegetables, less colonies were isolated on the Sugar Free Agar, Yeast Extract Agar and Aspergillus Differential Medium than on the other media. On those three media and on Plate Count Agar sporulation of many fungi was rather inhibited. On Aspergillus Differential Medium, on which Aspergillus flavus and Aspergillus parasiticus can be differentiated, no false positive colonies were to be seen.--On Malt Extract Agar with 7.5% NaCl the hydrophilic species were supressed, the xerophilic fungi were represented in greater number. The addition of 200 ppm rose bengal inhibited the growth of many fungi, but brought no rising of the colony count compared to Malt Extract Agar without rose bengal.--For the quantitive and qualitative mould plate count, Malt Extract Agar with 50 ppm Chloramphenicol and Chlortetracycline is recommended. For the detection of xerophilic moulds 7.5% NaCl should be added to that medium.--A proposition for the proceeding for the detection of moulds in foods is given.

[Comparison of methods for the quantitative detection of moulds in foods. II. Communication: effect of homogenisation conditions on mould plate count (author's transl)]. / Vergleichende Untersuchungen zur quantitativen Erfassung des Schimmelpilzbefalls bei Lebensmitteln. II. Mitteilung: Einffluss der Homogenisationsbedingungen auf die Schimmepilz-Koloniezahl.

The different effects of homogenisation of four commonly used homogenisating apparatus, such as Stomacher, Ultraturrax, Waring-Blender, Bühler-homogenisator) were compared with each other by applying 1 artificially and 6 naturally moulded, non-fluid food products. Furthermore the influence of sedimentation in the homogenisate as well as the time of homogenisation was examined. One part of the examination was the direct microscopic observation on stained Breed-smears, the other part the cultural methods (number of mould plate count on malt extract agar). The homogenisation effect of the Stomacher was as good as with all other mentioned apparatus with the food products applied, except for the home-made smoked sausage. With this home made smoked sausage, much better results were obtained by these homogenisating apparatus, especially by the Bühler Homogenisator. This is due to the fact that the sausage was minced to a much higher degree and thus the inner mould flora was set free.--A more tender effect of the Stomacher on hyphal elements could not be achieved.--Prolonging the time of homogenisation from 1 minute to 2 up to 4 minutes did not give any better results.--A short sedimentation of coarser food particles facilitates the pipetting of the homogenisates without influencing the mould counts.--The naturally moulded foods, which were kept at room temperature for several weeks, showed a significantly smaller number of plate count than of total mould count in contrary to those foods moulded just before experimental beginning.

[Comparison of methods for the quantitative detection of moulds in foods. I. Communication: selective staining procedures for the directmicroscopic mould count (author's transl)]. / Vergleichende Untersuchungen zur quantitativen Erfassung des Schimmelpilzbefalls bei Lebensmitteln. I. Mitteilung: Selektive Pilzfärbungen für den direktmikroskopischen Schimmelpilznachweis.

The most important proposed direct microscopic method for the detection of moulds were critically compared in 9 different nonfluid foods, of which 7 were naturally and 2 were artifically moulded.--Neither the Rot fragment test, nor the Howard Mould count or the NaOH treatment method proposed by Mossel (1975) were satisfying with non-fluid foods.--A significant improvement of the direct microscopic detection in the Breed-smear could be achieved by selective product specific staining of the fungi elements.--For low protein foods, a modified Pianese staining, and for low polysaccharide foods the Perjod-Schiff reaction proved to be appropriate and easy to carry out.--The slides of the selectively stained Breed-smears also allow a microscopic examination with high magnifications, so that a differenciation of fungus spores and hyphaes is possible.--Fungus spores, yeast cells and hyphal fragments can be counted by the method of Seck (1976). Hyphal fragments can also be recorded according to the prescription of the Howard Mould Count method.

[Psychosomatic aspects of breast carcinoma]. / Zur Psychosomatik des Mamma-Carcinoms

Psychological differences were compared between 25 female patients with carcinoma of the breast (mamma) and 25 patients with mastopathia cystica fibrosa. Our methods consisted in psychoanalytical interviews and MMPI-tests. We investigated the early childhood-period, the object relationships, the structurs of the personality and the psychological stress before the beginning of the physical illness. Patients with carcinoma of the breast show more frequent broken home situations, and inclination to idealize the past, depressive traits and a tendency to repress inner conflicts. The sexual behavior shows statistically more frequent abortions in the cancer group. In the beginning of the cancer we found statistically more frequent the loss of a meaningful personal relationships (e.g. death of the mother). Several differences between the personal structure were also found in the MMPI-tests.