Regulatory T Cells in the Pathogenesis and Healing of Chronic Human Dermal Leishmaniasis Caused by Leishmania (Viannia) Species

The immune inflammatory response is a double edged sword. During infectious diseases, regulatory T cells can prevent eradication of the pathogen but can also limit inflammation and tissue damage. We investigated the role of regulatory T cells in chronic dermal leishmaniasis caused by species of the parasite Leishmania that are endemic in South and Central America. We found that although individuals with chronic lesions have increased regulatory T cells in their blood and at skin sites where immune responses to Leishmania were taking place compared to infected individuals who do not develop disease, their capacity to control the inflammatory response to Leishmania was inferior. However, healing of chronic lesions at the end of treatment was accompanied by an increase in the number and capacity of regulatory T cells to inhibit the function of effector T cells that mediate the inflammatory response. Different subsets of regulatory T cells, defined by the expression of molecular markers, were identified during chronic disease and healing, supporting the participation of distinct regulatory T cells in the development of disease and the control of inflammation during the healing response. Immunotherapeutic strategies may allow these regulatory T cell subsets to be mobilized or mitigated to achieve healing

Impaired Limb Shortening following Stroke: What’s in a Name?

Difficulty advancing the paretic limb during the swing phase of gait is a prominent manifestation of walking dysfunction following stroke. This clinically observable sign, frequently referred to as 'foot drop', ostensibly results from dorsiflexor weakness.Here we investigated the extent to which hip, knee, and ankle motions contribute to impaired paretic limb advancement. We hypothesized that neither: 1) minimal toe clearance and maximal limb shortening during swing nor, 2) the pattern of multiple joint contributions to toe clearance and limb shortening would differ between post-stroke and non-disabled control groups.We studied 16 individuals post-stroke during overground walking at self-selected speed and nine non-disabled controls who walked at matched speeds using 3D motion analysis.No differences were detected with respect to the ankle dorsiflexion contribution to toe clearance post-stroke. Rather, hip flexion had a greater relative influence, while the knee flexion influence on producing toe clearance was reduced.Similarity in the ankle dorsiflexion, but differences in the hip and knee, contributions to toe clearance between groups argues strongly against dorsiflexion dysfunction as the fundamental impairment of limb advancement post-stroke. Marked reversal in the roles of hip and knee flexion indicates disruption of inter-joint coordination, which most likely results from impairment of the dynamic contribution to knee flexion by the gastrocnemius muscle in preparation for swing. These findings suggest the need to reconsider the notion of foot drop in persons post-stroke. Redirecting the focus of rehabilitation and restoration of hemiparetic walking dysfunction appropriately, towards contributory neuromechanical impairments, will improve outcomes and reduce disability

Macropore effects on phosphorus acquisition by wheat roots – a rhizotron study

Background and aimsMacropores may be preferential root pathways into the subsoil. We hypothesised that the presence of macropores promotes P-uptake from subsoil, particularly at limited water supply in surface soil. We tested this hypothesis in a rhizotron experiment with spring wheat (Triticum aestivum cv. Scirocco) under variation of fertilisation and irrigation.MethodsRhizotrons were filled with compacted subsoil (bulk density 1.4 g cm−3), underneath a P-depleted topsoil. In half of these rhizotrons the subsoil contained artificial macropores. Spring wheat was grown for 41 days with and without irrigation and 31P–addition. Also, a 33P–tracer was added at the soil surface to trace P-distribution in plants using liquid scintillation counting and radioactive imaging.ResultsFertilisation and irrigation promoted biomass production and plant P-uptake. Improved growing conditions resulted in a higher proportion of subsoil roots, indicating that the topsoil root system additionally promoted subsoil nutrient acquisition. The presence of macropores did not improve plant growth but tended to increase translocation of 33P into both above- and belowground biomass. 33P–imaging confirmed that this plant-internal transport of topsoil-P extended into subsoil roots.ConclusionsThe lack of penetration resistance in macropores did not increase plant growth and nutrient uptake from subsoil here; however, wheat specifically re-allocated topsoil-P for subsoil root growth