SEROLOGICAL ANALYSIS OF THYMUS AND SPLEEN GRAFTS

Thymus and spleen grafts from neonatal C57BL mice were implanted beneath the kidney capsule of (A x C57BL) F1 hybrids. At various intervals after implantation, the grafts were analyzed serologically. Cells of each graft were tested for the presence of cells of host origin, TL (thymus-leukemia) antigenicity, and sensitivity to the cytotoxic effect of guinea pig serum (GPS). Thymus grafts showed partial repopulation by host cells 11 days after grafting, and some grafts were completely repopulated by host cells 13 days after grafting. All thymus grafts were fully repopulated 18 days after grafting. With one exception, thymus grafts contained no significant number of TL-positive cells within 14 days after grafting. TL-positive cells appeared in thymus grafts examined 15 days after implantation, and their number increased up to the 18th day after implantation. Cells residing in thymus grafts remained sensitive to GPS throughout the period of observation. The acquisition of thymus-distinctive serological properties by host cells repopulating thymus grafts was similar in intact and in thymectomized recipients. Spleen grafts were completely repopulated by host cells as early as 8 days after grafting. The cells residing in spleen grafts remained TL-negative throughout the period of observation, and were refractory to the cytotoxic effect of GPS. It is thus apparent that, while both spleen and thymus grafts are invaded by TL-negative cells, only those entering the thymus acquire the antigen. The nature of the process by which the thymus endows thymus-distinctive properties on cells entering it is discussed

Mechanisms of action of hESC-secreted proteins that enhance human and mouse myogenesis.

Adult stem cells grow poorly in vitro compared to embryonic stem cells, and in vivo stem cell maintenance and proliferation by tissue niches progressively deteriorates with age. We previously reported that factors produced by human embryonic stem cells (hESCs) support a robust regenerative capacity for adult and old mouse muscle stem/progenitor cells. Here we extend these findings to human muscle progenitors and investigate underlying molecular mechanisms. Our results demonstrate that hESC-conditioned medium enhanced the proliferation of mouse and human muscle progenitors. Furthermore, hESC-produced factors activated MAPK and Notch signaling in human myogenic progenitors, and Delta/Notch-1 activation was dependent on MAPK/pERK. The Wnt, TGF-β and BMP/pSmad1,5,8 pathways were unresponsive to hESC-produced factors, but BMP signaling was dependent on intact MAPK/pERK. c-Myc, p57, and p18 were key effectors of the enhanced myogenesis promoted by the hECS factors. To define some of the active ingredients of the hESC-secretome which may have therapeutic potential, a comparative proteomic antibody array analysis was performed and identified several putative proteins, including FGF2, 6 and 19 which as ligands for MAPK signaling, were investigated in more detail. These studies emphasize that a youthful signaling of multiple signaling pathways is responsible for the pro-regenerative activity of the hESC factors

Is Professional Soccer a Risk for Their “Lives Afterwards”? A Social-Sciences-Based Examination of Retired Professional Soccer Players from a Long-Term Perspective

Most professional soccer players’ careers end before their forties. Consequently, many of them face a relatively early retirement from their profession, thus facing multifaceted changes and potential issues of adjustments in different areas of their lives. Public discussion and therein expressed concerns have led to increased attention on the topic, notably among practitioners and researchers. This study described and analyzed central retirement transition and adjustment outcomes of ex-professional soccer players from a social sciences and long-term perspective. A total of 78 exprofessionals completed the online questionnaire, most of them having played in the highest German soccer division for several years and having retired from professional soccer 10 years or more ago. Overall, 8.9% (95% CI 2.5 to 21.2; n = 45) showed signs of mental health problems. Compared to the results of a gender- and age-matched sample from the German population, retired ex-professionals were significantly more satisfied with their life and their personal income, and assessed themselves as having a higher subjective social status. Although further evidence is necessary to draw any final conclusion, our results do not point to those publicly discussed concerning central retirement transition and adjustment outcomes of (average) former professional soccer players in the long run

hESC-secreted proteins can be enriched for multiple regenerative therapies by heparin-binding.

This work builds upon our findings that proteins secreted by hESCs exhibit pro-regenerative activity, and determines that hESC-conditioned medium robustly enhances the proliferation of both muscle and neural progenitor cells. Importantly, this work establishes that it is the proteins that bind heparin which are responsible for the pro-myogenic effects of hESC-conditioned medium, and indicates that this strategy is suitable for enriching the potentially therapeutic factors. Additionally, this work shows that hESC-secreted proteins act independently of the mitogen FGF-2, and suggests that FGF-2 is unlikely to be a pro-aging molecule in the physiological decline of old muscle repair. Moreover, hESC-secreted factors improve the viability of human cortical neurons in an Alzheimers disease (AD) model, suggesting that these factors can enhance the maintenance and regeneration of multiple tissues in the aging body

THE DIFFERING SURVIVAL OF NORMAL AND SENSITIZED SPLEEN CELLS TRANSFERRED TO ALLOGENEIC HOSTS

Normal and isoimmune C3H and C57BL spleen cells were transferred intravenously into normal and irradiated allogeneic recipients and the fate of the donor cells determined by differential cytotoxicity and radioautographic techniques. It was found that spleen cells sensitized against their prospective recipients could be identified in the host's spleen for 1 day, whereas normal donor cells survived 2 to 3 days. Spleen cells presensitized with an indifferent antigen had survival times similar to normal donor cells. Irradiation of the recipients prior to cell transfer eliminated any difference in survival times between normal and presensitized donor cells in allogeneic hosts. It is concluded that the host plays an important role in the rapid destruction of spleen cells presensitized against host antigens. Experiments in which sensitized and normal C57BL spleen cells were mixed and transferred into normal C3H mice indicated that as little as 5 to 10 per cent of the donor cell population need be sensitized for the entire mixture to behave as if it were obtained from a sensitized animal, as shown by its elimination in the 1-day interval

Kafka stochastisch. Rekontextualisierung und Recodierung in computergestützten Textgeneratoren

Computergestützte kombinatorische Textgeneratoren arbeiten mit Strukturen und Vokabularen von Ausgangstexten, die im Prozess der Textgenerierung zur Herstellung neuer Texte verwendet werden. Auf eine Dekontextualisierung und Detextualisierung durch eine Zerlegung des Ausgangstexts folgt eine Retextualisierung und Rekontextualisierung durch die Herstellung und Publikation der generierten Texte. Anhand der Textgeneratoren von Theo Lutz: Stochastische Texte (1959) und Kathrin Passig: Gomringador (2018-) arbeitet der Beitrag das analytische Potenzial eines Rekontextualisierungskonzepts in den jeweils spezifischen mediengeschichtlichen Zusammenhängen heraus