Compositional turnover and variation in Eemian pollen sequences in Europe

Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes...     

Detection of bacterial endotoxin in human tissues

Detection of bacterial lipopolysaccharide (LPS) in the absence of overt infection is a challenging problem in tissue homogenates and other complex samples. We found that conventional Limulus amebocyte lysate (LAL) assays are not suitable for this purpose due to interference from beta-glucan-like molecules. In contrast, a modified LAL assay that is unaffected by beta-glucan-like molecules was able to detect LPS in infected tissue and in a subset of clinically aseptic tissues. A two-step LAL assay was used to exclude the possibility of false positives due to nonspecific amidases. False positives due to sample color were also excluded, as were false negatives due to assay inhibition. This is the first report to successfully detect LPS in tissue in the absence of overt infection. This approach may be extremely useful in assessing recent hypotheses that subclinical levels of bacteria contribute to a wide range of chronic diseases.     

Some problems of forest transformation at the transition to the oligocratic/<Emphasis Type="Italic">Homo sapiens</Emphasis> phase of the Holocene interglacial in northern lowlands of central Europe

The paper discusses the main changes in the composition of mixed deciduous forests which occurred mostly between 5,000 and 2,000 b.p., based on selected pollen diagrams from the lowlands of Germany, Denmark and Poland, and including two pollen diagrams from varved sediments, used as reference sites, and on isopollen maps for Poland. The Ulmus retreat is shown on maps, and additional data for its pathogenic origin are presented. Corylus declines at ca. 3,500 b.p. at both reference sites, and its connection with Fagus expansion in the west and Carpinus expansion in the east is discussed. The nature of post-Atlantic transitory shrub–forest communities with dominant Corylus and Quercus is presented. Relationships between the history of Fagus and Carpinus and the development of human settlements are shown. Human impact has been admitted as one of the most important driving forces determining vegetational development since the time of fully developed Neolithic cultures. Other very important abiotic factors were the climate (particularly after 2,500 b.p.), and soil degradation.     

Cytokines synergistically induce osteoclast differentiation: support by immortalized or normal calvarial cells

Conditionally immortalizedmurine calvarial (CIMC) cells that support differentiation ofprecursors into mature osteoclasts were isolated. All six CIMC celllines supported osteoclast differentiation in response to1,25-dihydroxyvitamin D₃ or interleukin (IL)-11. CIMC-4cells also supported osteoclast differentiation in response to tumornecrosis factor (TNF)-, IL-1, or IL-6. The resultant multinucleated cells expressed tartrate-resistant acid phosphatase andformed resorption lacunae on mineralized surfaces. CIMC-4 cells,therefore, establish an osteoclast differentiation assay that isresponsive to many cytokines and does not rely on isolation of primarystromal support cells. Low concentrations of the cytokines synergistically stimulated differentiation when osteoclast precursors were cocultured with either CIMC-4 cells or primary calvarial cells.Osteoclast differentiation induced by all stimuli other thanTNF- was completely blocked by osteoprotegerin, whether thestimulators were examined alone or in combination. Moreover, study ofprecursors that lack TNF- receptors showed that TNF- inducesosteoclast differentiation primarily through direct actions onosteoclast precursors, which is a distinct mechanism from that used bythe other bone-resorptive agents examined in this study.