Five regionally significant Weichselian glacial events, each separated by terrestrial and marine interstadial conditions, are described from northwestern Russia. The first glacial event took place in the Early Weichselian. An ice sheet centred in the Kara Sea area dammed up a large lake in the Pechora lowland. Water was discharged across a threshold on the Timan Ridge and via an ice‐free corridor between the Scandinavian Ice Sheet and the Kara Sea Ice Sheet to the west and north into the Barents Sea. The next glaciation occurred around 75–70 kyr BP after an interstadial episode that lasted c. 15 kyr. A local ice cap developed over the Timan Ridge at the transition to the Middle Weichselian. Shortly after deglaciation of the Timan ice cap, an ice sheet centred in the Barents Sea reached the area. The configuration of this ice sheet suggests that it was confluent with the Scandinavian Ice Sheet. Consequently, around 70–65 kyr BP a huge ice‐dammed lake formed in the White Sea basin (the ‘White Sea Lake’), only now the outlet across the Timan Ridge discharged water eastward into the Pechora area. The Barents Sea Ice Sheet likely suffered marine down‐draw that led to its rapid collapse. The White Sea Lake drained into the Barents Sea, and marine inundation and interstadial conditions followed between 65 and 55 kyr BP. The glaciation that followed was centred in the Kara Sea area around 55–45 kyr BP. Northward directed fluvial runoff in the Arkhangelsk region indicates that the Kara Sea Ice Sheet was independent of the Scandinavian Ice Sheet and that the Barents Sea remained ice free. This glaciation was succeeded by a c. 20‐kyr‐long ice‐free and periglacial period before the Scandinavian Ice Sheet invaded from the west, and joined with the Barents Sea Ice Sheet in the northernmost areas of northwestern Russia. The study area seems to be the only region that was invaded by all three ice sheets during the Weichselian. A general increase in ice‐sheet size and the westwards migrating ice‐sheet dominance with time was reversed in Middle Weichselian time to an easterly dominated ice‐sheet configuration. This sequence of events resulted in a complex lake history with spillways being re‐used and ice‐dammed lakes appearing at different places along the ice margins at different times.
Preterm birth, bacterial colonization, and formula feeding predispose to necrotizing enterocolitis (NEC). Antibiotics are commonly administered to prevent sepsis in preterm infants, but it is not known whether this affects intestinal immunity and NEC resistance. We hypothesized that broad-spectrum antibiotic treatment improves NEC resistance and intestinal structure, function, and immunity in neonates. Caesarean-delivered preterm pigs were fed 3 days of parenteral nutrition followed by 2 days of enteral formula. Immediately after birth, they were assigned to receive either antibiotics (oral and parenteral doses of gentamycin, ampicillin, and metronidazole, ANTI, n ϭ 11) or saline in the control group (CON, n ϭ 13), given twice daily. NEC lesions and intestinal structure, function, microbiology, and immunity markers were recorded. None of the ANTI but 85% of the CON pigs developed NEC lesions by day 5 (0/11 vs. 11/13, P Ͻ 0.05). ANTI pigs had higher intestinal villi (ϩ60%), digestive enzyme activities (ϩ53-73%), and goblet cell densities (ϩ110%) and lower myeloperoxidase (Ϫ51%) and colonic microbial density (10 5 vs. 10 10 colony-forming units, all P Ͻ 0.05). Microarray transcriptomics showed strong downregulation of genes related to inflammation and innate immune response to microbiota and marked upregulation of genes related to amino acid metabolism, in particular threonine, glucose transport systems, and cell cycle in 5-day-old ANTI pigs. In a follow-up experiment, 5 days of antibiotics prevented NEC at least until day 10. Neonatal prophylactic antibiotics effectively reduced gut bacterial load, prevented NEC, intestinal atrophy, dysfunction, and inflammation and enhanced expression of genes related to gut metabolism and immunity in preterm pigs.
BB, Thymann T. Similar efficacy of human banked milk and bovine colostrum to decrease incidence of necrotizing enterocolitis in preterm piglets. Am J Physiol Regul Integr Comp Physiol 305: R4 -R12, 2013. First published May 8, 2013 doi:10.1152/ajpregu.00094.2013.-Preterm birth and formula feeding predispose to necrotizing enterocolitis (NEC) in infants. As mother's milk is often absent following preterm delivery, infant formula (IF) and human donor milk (HM) are frequently used as alternatives. We have previously shown that porcine and bovine colostrum (BC) provide similar NEC protection in preterm piglets relative to IF. We hypothesized that HM exerts similar effects and that this effect is partly species-independent. Preterm piglets (n ϭ 40) received 2 days of total parenteral nutrition, followed by a rapid transition to full enteral feeding (15 ml·kg Ϫ1 ·2 h Ϫ1 ) for 2 days using BC (n ϭ 13), HM (n ϭ 13), or IF (n ϭ 14). Intestinal passage time and hexose absorption were tested in vivo. Body and organ weights were recorded on day 5, and macroscopic NEC lesions in the gastrointestinal tract were assessed. Intestinal samples were collected for determination of histomorphology, histopathology, tissue IL-6 and IL-8, organic acids, bacterial adherence by fluorescence in situ hybridization score, and digestive enzyme activities. Relative to IF, pigs from BC and HM showed longer intestinal passage time; higher weight gain, hexose absorptive capacity, mucosal proportion, and enzyme activities; lower NEC incidence, organic acid concentration, and IL-8 concentration; and reduced histopathology lesions. Tissue IL-6 concentration and bacterial adherence score were lower for HM, relative to both BC and IF groups. We conclude that BC and HM are both superior to IF in stimulating gut structure, function, and NEC resistance in preterm piglets.
August): Depositional environments and sea-level changes deduced from Middle Weichselian tidally influenced sediments, Arkhangelsk region, northwestern Russia. Boreas, Vol. 35, pp. 521 Á538. Oslo. ISSN 0300-9483.Deposits from a Middle Weichselian transgression, the Mezen Transgression, are found in coastal sections in the Mezen and Chyorskaya Bays, northwestern Russia. The marine event is bracketed between two ice advances from the Barents and Kara Sea shelves and dated by Optically Stimulated Luminescence (OSL) to around 60 kyr BP. The deposits represent a shallowing upward succession from offshore marine to intertidal coastal environments. Relative sea-level maximum was at least 40 m above the present owing to significant isostatic subsidence. The sedimentary record is dominated by shallow-marine, subtidal deposits bounded below by an erosion surface representing a downward shift in facies and above by subaerial exposure. The succession reflects deposition during forced regression due to isostatic uplift. A rapidly aggrading succession of subtidal deposits at one site suggests a relative sea-level rise or stillstand superimposed on the isostatically controlled sea-level fall. The rhythmic tidal deposits allow identification of semi-monthly to yearly cycles, providing an estimate of the sedimentation rate of 39 cm/year. This implies a high sediment yield and a rapid relative sea-level rise. We correlate this signal with the rapid eustatic sea-level rise at the end of OIS 4 known from deep-sea records.
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