Platyamoeba nucleolilateralis n. sp. from the Chesapeake Bay Region

Members of the genus Platyamoeba are among the most common of the free-living brackish and marine amoebae; yet, to date only twelve species have been documented in the literature and only a limited number of habitats have been sampled globally. During the course of a systematic survey of salt-marsh amoebae along the east coast of the United States, a new species of Platyamoeba was discovered in sediment samples obtained from a salt marsh at Assateague Island, VA. The species can be distinguished from all other described species within the genus by the presence of a nucleus with a single parietal nucleolus and a floating form with long tapering pseudopods. Its shape varies from flabellate to spatulate as described for species of Platyamoeba and Vannella. The fine structure of the glycocalyx, however, is characteristic of Platyamoeba.     

The history of surface electromyography

The history of muscle pain and dysfunction is viewed through the lens of a four factor theory of histologic (tissue related) issues, psychologic (emotional) issues, sensory motor (movement) issues, and biomechanical (postural) issues. The historical antecedents of surface electromyography are reviewed.     

Haplotype blocks and linkage disequilibrium in the human genome

There is great interest in the patterns and extent of linkage disequilibrium (LD) in humans and other species. Characterizing LD is of central importance for gene-mapping studies and can provide insights into the biology of recombination and human demographic history. Here, we review recent developments in this field, including the recently proposed 'haplotype-block' model of LD. We describe some of the recent data in detail and compare the observed patterns to those seen in simulations.     

Natural versus adaptive regulatory T cells

The regulation of immune responses to self-antigens is a complex process that involves maintaining self-tolerance while retaining the capacity to mount robust immune responses against invading microorganisms. Over the past few years, many new insights into this process have been gained, leading to the re-emergence of the idea that regulatory T (T(Reg)) cells are a central mechanism of immune regulation. These insights have raised fundamental questions concerning what constitutes a T(Reg) cell, where they develop and what signals maintain T(Reg)-cell populations in a functional state. Here, we propose the existence of two subsets of CD4+ T(Reg) cells--natural and adaptive--that differ in terms of their development, specificity, mechanism of action and dependence on T-cell receptor and co-stimulatory signalling.     

Lymphotoxin/light,lymphoid microenvironments and autoimmune disease

Much of the efficiency of the immune system is attributed to the high degree of spatial and temporal organization in the secondary lymphoid organs. Signalling through the lymphotoxin (LT) pathway is a crucial element in the maintenance of this organized microenvironment. The effect of altering lymphoid microenvironments on immune responses remains relatively unexplored. Inhibitors of the LT and LIGHT pathways have been shown to reduce disease in a wide range of autoimmune models. This approach has provided a tool to probe the effect of manipulation of the microenvironment on both normal and pathological immune responses.