β2-microglobulin is a systemic pro-aging factor that impairs cognitive function and neurogenesis

Aging drives cognitive and regenerative impairments in the adult brain, increasing susceptibility to neurodegenerative disorders in healthy individuals. Experiments using heterochronic parabiosis, in which the circulatory systems of young and old animals are joined, indicate that circulating pro-aging factors in old blood drive aging phenotypes in the brain. Here we identify β2-microglobulin (B2M), a component of major histocompatibility complex class 1 (MHC I) molecules, as a circulating factor that negatively regulates cognitive and regenerative function in the adult hippocampus in an age-dependent manner. B2M is elevated in the blood of aging humans and mice, and it is increased within the hippocampus of aged mice and young heterochronic parabionts. Exogenous B2M injected systemically, or locally in the hippocampus, impairs hippocampal-dependent cognitive function and neurogenesis in young mice. The negative effects of B2M and heterochronic parabiosis are, in part, mitigated in the hippocampus of young transporter associated with antigen processing 1 (Tap1)-deficient mice with reduced cell surface expression of MHC I. The absence of endogenous B2M expression abrogates age-related cognitive decline and enhances neurogenesis in aged mice. Our data indicate that systemic B2M accumulation in aging blood promotes age-related cognitive dysfunction and impairs neurogenesis, in part via MHC I, suggesting that B2M may be targeted therapeutically in old age.

Wirksamkeit der umfassenden kardiologischen Rehabilitation und Sekundärprävention: klinische und epidemiologische Evidenz

Zusammenfassung Die umfassende kardiologische Rehabilitation ist die Summe von koordinierten Maßnahmen, welche die Folgen von Herzerkrankungen vermindern, die Morbidität und Mortalität reduzieren und die gesundheitsbezogene Lebensqualität einschließlich der psychosozialen Situation der Patienten verbessern sollen. Dazu ist die Bereitstellung strukturierter sekundärpräventiver Strategien besonders wichtig. Schwerpunkte dieser Maßnahmen sind die Trainingstherapie und Aktivitätsberatung sowie Ernährungstherapie und -beratung, Raucherentwöhnung, psychosoziale Intervention und Pharmakotherapie (Ades 2001).

(Table 1) Calcium isotope composition, Mg/Ca, Sr/Ca and U/Ca ratios of calcareous cysts of Thoracosphaera heimii

We investigated the influences of temperature, salinity and pH on the calcium isotope as well as trace and minor element (uranium, strontium, magnesium) to Ca ratios on calcium carbonate cysts of the calcareous dinoflagellate species Thoracosphaera heimii grown in laboratory cultures. The natural habitat of this species is the photic zone (preferentially at the chlorophyll maximum depth) of temperate to tropical oceans, and it is abundant in deep-sea sediments over the entire Cenozoic. In our experiments, temperatures ranged from 12 to 30 °C, salinity from 36.5 to 38.8 and pH from 7.9 to 8.4. The delta44/40Ca of T. heimii cysts resembles that of other marine calcifiers, including coccolithophores, foraminifers and corals. However, its temperature sensitivity is considerably smaller and statistically insignificant, and T. heimii might serve as a recorder of changes in seawater delta44/40Ca over geologic time. The Sr/Ca ratios of T. heimii cysts show a pronounced temperature sensitivity (0.016 mmol/mol °C**-1) and have the potential to serve as a palaeo-sea surface temperature proxy. No clear temperature- and pH-dependences were observed for Mg/Ca. U/Ca seems to be influenced by temperature and pH, but the correlations change sign at 23 °C and pH 8.2, respectively.

Dinoflagellate cyst counts and age model from sediment samples of ODP Hole 175-1085A

Sediment samples from ODP Site 1085 were investigated in order to obtain more information on the initiation and development of the Benguela upwelling system during the middle and upper Miocene. In particular, our intent was to establish the causes of the upwelling as well as the response of the upwelling regime to the development of the Antarctic Circumpolar Current. Based on changes in the calcareous dinoflagellate cyst association, we found an initial increase of the dinoflagellate cyst productivity, probably related to the initiation of upwelling about 11.8 Ma ago. Two distinct increases in cyst productivity in conjunction with temperature decreases of the upper water masses reflect upwelling pulses off Namibia and occur at the end of the Miocene cooling events Mi5 (about 11.5 Ma) and Mi6 (about 10.5 Ma). Both cooling events are associated with an ice volume increase in Antarctica and are thought to have led to an increase in southeasterly winds, possibly causing these two upwelling pulses. We demonstrate a decrease in dinoflagellate cyst productivity and enhanced terrigenous input via the Orange River after the Mi5 event. At about 11.1 Ma, the dinoflagellate cyst productivity increases again. The polar cyst species Caracomia arctica occurs here for the first time. This implies an influence of subantarctic mode water and therefore a change in the quality of the upwelling water which allowed the Benguela upwelling to develop into modern conditions. From about 10.4 Ma, C. arctica forms a permanent part of the association, pointing to an establishment of the upwelling regime.

Investigar problemas ambientales en Antropología Social Pertinencia Social y Científica: una aproximación al campo. En: Avá, nº 18

Este texto abordará la importancia de la investigación de problemas ambientales en antropología social. Podemos afirmar que la relación entre sociedad y naturaleza se ha mantenido como tema de interés desde los inicios de la antropología como disciplina, primeramente, con aportes desde el determinismo ambiental, y luego, con estudios sobre la etnociencia, las clasificaciones y conocimiento de la flora y fauna (Conklin, 955; Berlin, 1973), la adaptación ecológica y ecosistemas (Steward, 1968; Rappaport, 1968), y la relación entre hombres y otras especies (White, 1949; Ingold, 1986; Haraway, 2003; Raffles, 2010). Este interés se ha acentuado en las últimas décadas al incrementar la atención en la situación climática, la crisis ecológica y los problemas ambientales Haenn & Wilk, 2006) que han dado un giro a la forma en que experimentamos nuestro entorno, así como en las construcciones y entendimientos de estos problemas.