Potential of Macrostomum lignano to recover from γ-ray irradiation

Stem cells are the only proliferating cells in flatworms and can be eliminated by irradiation with no damage to differentiated cells. We investigated the effect of fractionated irradiation schemes on Macrostomum lignano, namely, on survival, gene expression, morphology and regeneration. Proliferating cells were almost undetectable during the first week post-treatment. Cell proliferation and gene expression were restored within 1 month in a dose-dependent manner following exposure to up to 150 Gy irradiation. During recovery, stem cells did not cross the midline but were restricted within lateral compartments. An accumulated dose of 210 Gy resulted in a lethal phenotype. Our findings demonstrate that M. lignano represents a suitable model system for elucidating the effect of irradiation on the stem cell system in flatworms and for improving our understanding of the recovery potential of severely damaged stem-cell systems

Dynamic Imaging of the Effector Immune Response to Listeria Infection In Vivo

Host defense against the intracellular pathogen Listeria monocytogenes (Lm) requires innate and adaptive immunity. Here, we directly imaged immune cell dynamics at Lm foci established by dendritic cells in the subcapsular red pulp (scDC) using intravital microscopy. Blood borne Lm rapidly associated with scDC. Myelomonocytic cells (MMC) swarmed around non-motile scDC forming foci from which blood flow was excluded. The depletion of scDC after foci were established resulted in a 10-fold reduction in viable Lm, while graded depletion of MMC resulted in 30–1000 fold increase in viable Lm in foci with enhanced blood flow. Effector CD8+ [CD8 superscript +] T cells at sites of infection displayed a two-tiered reduction in motility with antigen independent and antigen dependent components, including stable interactions with infected and non-infected scDC. Thus, swarming MMC contribute to control of Lm prior to development of T cell immunity by direct killing and sequestration from blood flow, while scDC appear to promote Lm survival while preferentially interacting with CD8+ [CD8 superscript +] T cells in effector sites.National Institutes of Health (U.S.) (Grant P01AI-071195

Decreased postural control in adolescents born with extremely low birth weight

This is an accepted manuscript of an article published by Springer in Experimental Brain Research on 14 March 2015, available online: https://doi.org/10.1007/s00221-015-4239-3 The accepted version of the publication may differ from the final published version.The survival rates of infants born preterm with extremely low birth weight (ELBW ≤ 1000 g) have gradually improved over the last decades. However, these infants risk to sustain long-term disorders related to poor neurodevelopment. The objective was to determine whether adolescents born with ELBW have decreased postural control and stability adaptation. Twenty-nine ELBW subjects performed posturography with eyes open and closed under unperturbed and perturbed standing by repeated calf vibration. Their results were compared with twenty-one age- and gender-matched controls born after full-term pregnancy. The ELBW group had significantly decreased stability compared with controls in anteroposterior direction, both during the easier quiet stance posturography (p = 0.007) and during balance perturbations (p = 0.007). The ELBW group had similar stability decrease in lateral direction during balance perturbations (p = 0.013). Statistically, the stability decreases were similar with eyes closed and open, but proportionally larger with eyes open in both directions. Both groups manifested significant adaptation (p ≤ 0.023) to the balance perturbations in anteroposterior direction, though this adaptation process could not compensate for the general stability deficits caused by ELBW on postural control. Hence, adolescent survivors of ELBW commonly suffer long-term deficits in postural control, manifested as use of substantially more recorded energy on performing stability regulating high-frequency movements and declined stability with closed and open eyes both in anteroposterior and lateral direction. The determined relationship between premature birth and long-term functional deficits advocates that interventions should be developed to provide preventive care in neonatal care units and later on in life.Published versio