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The sensitivity of the climate system to changes in radiative forcing is crucial for our understanding of past and future climates. Especially important are feedbacks related to melting of ice sheets like the Greenland ice sheet (GIS) and its potential impact on the Atlantic meridional overturning circulation (AMOC). These effects are likely to delay and dampen predicted long-term warming trends. Estimates of climate sensitivity may be deduced from palaeoclimate-reconstructions, but this raises the question whether past climate sensitivity is applicable to the future. Therefore we have analysed the impact of GIS melt water on the AMOC strength in two past warm climates (last interglacial and early present interglacial) and three future scenarios with three different model parameter sets. These model parameter sets represent three different model sensitivities to freshwater perturbation: low, moderate and high. In both the moderate and high sensitivity versions, we find for lower GIS melt rates (below 54 mSv, Sv = 10 m/s) a clear difference between past and future warm climates in the sensitivity of the AMOC to GIS melt. This difference is connected to the convective activity in the Labrador Sea and the amount of additional surface freshening due to sea ice melting. In contrast, for higher GIS melt rates (over 54 mSv) we find similar reductions of the AMOC strength in all cases. Considering the low sensitivity version of our model, we find that for all GIS melt rates the influence of freshwater forcing on the AMOC is independent of the background climate. Our results and implications are thus strongly determined by the parameter set considered in our model. Nonetheless, our results from two out of three model versions suggest that proxy-based reconstructions of past AMOC sensitivity to GIS melt are likely to be misleading if interpreted for future applications. [ABSTRACT FROM AUTHOR]

The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene Thermal Maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveal a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from a previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in a ocean surface cooling of up to 2K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that the modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come. [ABSTRACT FROM AUTHOR]

Tests for antivimentin antibodies (AVA) were performed on 50 systemic lupus erythematosus (SLE) and 63 control sera by indirect immunofluorescence and enzyme linked immunosorbent assay (ELISA). The prevalence was significantly raised in SLE (38% and 50% of sera positive for IgM-AVA and IgG-AVA, respectively, by immunofluorescence; 36% and 64% of sera positive for IgM-AVA and IgG-AVA, respectively, by ELISA) in comparison with the control sera. A significant correlation existed between IgM-AVA, on the one hand, and anticardiolipin antibodies (ACA) and anti-single-stranded DNA (ssDNA), on the other. A stepwise principal component analysis demonstrated that IgM-AVA and IgG-AVA accounted for 71% of the total variance in SLE (50 patients x 5 parameters = total variance). Twenty ACA positive serum samples from patients with syphilis were therefore tested for the presence of AVA, but hardly any were found to be positive. IgM-AVA from patients with SLE were inhibited by cardiolipin and absorbed with ssDNA. An association between AVA positivity and arthralgia was also shown in SLE. [ABSTRACT FROM PUBLISHER]

Twenty-five patients with idiopathic Raynaud's phenomenon were followed prospectively for a mean period of 48 months. Clinical and laboratory assessments were performed on admission and on followup. The sera were analyzed for the presence of autoantibodies (antinuclear, antiskeleton and antiorganelle antibodies). Sixteen patients were antinuclear antibody positive and 2 anticentromere antibody positive. Eight patients produced antivimentin, 5 antimitochondrial, 4 anti-Golgi complex, and 3 anticentriol antibodies. Eleven patients produced antidesmosome antibodies. Only one patient (anti-RNP and antidesmosome antibody positive) developed a systemic disease (mixed connective tissue disease) during followup. The initial screening of sera may help to classify Raynaud's phenomenon as idiopathic more accurately.

The determination of non-organ-specific autoantibodies is a major tool in the serological diagnosis of rheumatic disorders. Antinuclear antibodies (ANA) are routinely determined by indirect immunofluorescence (IFL) testing on cryostat sections, but the use of cultured cell lines now allows to detect new antibody specificities that are obscured on tissue sections. Titres and IFL patterns of antibodies add further information to the interpretation of results. Homogeneous or perimembranous patterns point to systemic lupus erythematosus (SLE) which is better characterized by the presence of antibodies to double-stranded DNA or to the Smith-antigen (Sm-antigen) detected by other methods. Antibodies to extractable nuclear antigens (ENA) are strongly correlated with connective tissue disease, the main representatives of which may now be identified serologically by the presence of marker anti-ENA antibodies.

The detection of circulating serum antibodies that react with various nuclear or cytoplasmic antigens of cell substrates has become an established investigation in the diagnosis of autoimmune diseases. Antinuclear antibodies as well as some non-organ-specific anticytoplasmic autoantibodies might be of diagnostic significance. Some examples are anti-mitochondrial antibodies in autoimmune liver diseases, anti-cytoskeletal antibodies in chronic active hepatitis, polymyositis and infectious diseases and microsomal antibodies in juvenile cryptogenic liver cirrhosis. New techniques and methods such as indirect immunofluorescence on tissue culture substrates, enzymelinked immunoassays and immunoblotting tests now form the basis of further studies. These tests allow a more sensitive and specific assay for lysosomal and Golgi apparatus antigens. It may be possible to more precisely associate particular anti-cytoplasmic antibodies that react with autoimmune diseases.