Characterization of B cells in healthy pregnant women from late pregnancy to post-partum: a prospective observational study

Abstract BACKGROUND: B cells play a role in pregnancy due to their humoral and regulatory activities. To our knowledge, different maturational stages (from transitional to memory) of circulating B cell subsets have not yet been characterized (cell quantification and phenotype identification) in healthy pregnant women. Thus, the objective of our study was to characterize these subsets (as well as regulatory B cells) from late pregnancy to post-partum and to compare them with the circulating B cells of non-pregnant women. METHODS: In all of the enrolled women, flow cytometry was used to characterize the circulating B cell subsets according to the expression of IgD and CD38 (Bm1-Bm5 classification system). Regulatory B cells were characterized based on the expression of surface antigens (CD24, CD27, and CD38) and the production of IL-10 after lipopolysaccharide stimulation. RESULTS: Compared to the absolute counts of B cells in the non-pregnant women (n = 35), those in the pregnant women (n = 43) were significantly lower (p < 0.05) during the 3rd trimester of pregnancy and on delivery day (immediately after delivery). The percentages of these cells on delivery day and at post-partum were significantly lower than those in the non-pregnant women. In general, the absolute counts and percentages of the majority of the B cell subsets were significantly lower in the 3rd trimester of pregnancy and on delivery day than in the non-pregnant women. However, these counts and percentages did not differ significantly between the post-partum and the non-pregnant women. The most notable exceptions to the above were the percentages of naïve B cells (which were significantly higher in the 3rd trimester and on delivery day than in the non-pregnant women) and of CD24(hi)CD38(hi) regulatory B cells (which were significantly higher in the post-partum than in the non-pregnant women). CONCLUSION: According to our study, the peripheral B cell compartment undergoes quantitative changes during normal late pregnancy and post-partum. Such findings may allow us to better understand immunomodulation during human pregnancy and provide evidence that could aid in the development of new strategies to diagnose and treat pregnancy-associated disturbances. Our findings could also be useful for studies of the mechanisms of maternal responses to vaccination and infection.

Age determination and stable isotope records of sediment core M78/1_235-1

Paleoenvironmental studies and climate models demonstrate that fluvial runoff and moisture availability in the Caribbean hinterland react very sensitively to climatic variations. Late Pleistocene and Holocene climate records document pronounced dry and wet periods over tropical South America mainly caused by shifts of the Intertropical Convergence Zone (ITCZ). However, forcing mechanisms for changes in the ITCZ position remain controversial. Here we present high-resolution foraminiferal Ba/Ca and d18Oseawater records from a core located within the Orinoco River outflow documenting abrupt hydrological changes in the Orinoco catchment area during the deglacial and Holocene. Our data, obtained from the surface-dwelling foraminifera Globigerinoides ruber (pink), show an abrupt increase in Ba/Ca ratios in the early Holocene, starting ~600 yr after the end of the Younger Dryas (YD) cold interval at ca. 10.8 ka and suggesting a massive reorganization of moisture sources in northern South America. In contrast, the salinity dependent d18Oseawater from the same samples shows a gradual decrease starting at the end of the YD. The offset of our Ba/Ca peak excludes meltwater release in conjunction with the northern Andean glacier retreat well before the end of the YD as a forcing mechanism. We suggest that the Ba/Ca record documents an abrupt increase in Ba-rich waters of a northern Andean source caused by the insolation-driven shift of the ITCZ and/or enhanced monsoon activity.

Seasonal changes in sediment core PS1795-2

The Weddell Sea and the associated Filchner-Rønne Ice Shelf constitute key regions for global bottomwater production today. However, little is known about bottom-water production under different climate and icesheet conditions. Therefore, we studied core PS1795, which consists primarily of fine-grained siliciclastic varves that were deposited on contourite ridges in the southeastern Weddell Sea during the Last Glacial Maximum (LGM). We conducted high-resolution X-ray fluorescence (XRF) analysis and grain-size measurements with the RADIUS tool (Seelos and Sirocko, 2005, doi:10.1111/j.1365-3091.2005.00715.x) using thin sections to characterize the two seasonal components of the varves at sub-mm resolution to distinguish the seasonal components of the varves. Bright layers contain coarser grains that can mainly be identified as quartz in the medium-to-coarse silt grain size. They also contain higher amounts of Si, Zr, Ca, and Sr, as well as more ice-rafted debris (IRD). Dark layers, on the other hand, contain finer particles such as mica and clay minerals from the chlorite and illite groups. In addition, Fe, Ti, Rb, and K are elevated. Based on these findings as well as on previous analyses on neighbouring cores, we propose a model of enhanced thermohaline convection in front of a grounded ice sheet that is supported by seasonally variable coastal polynya activity during the LGM. Accordingly, katabatic (i.e. offshore blowing) winds removed sea ice from the ice edge, leading to coastal polynya formation. We suggest that glacial processes were similar to today with stronger katabatic winds and enhanced coastal polynya activity during the winter season. Under these conditions, lighter coarser-grained layers are likely glacial winter deposits, when brine rejection was increased, leading to enhanced bottom-water formation and increased sediment transport. Vice versa, darker finer-grained layers were then deposited during less windier season, mainly during summer, when coastal polynya activity was likely reduced.

Figure 5. Trace metal analysis of sediment core PS1506-1

An increase in whole ocean alkalinity during glacial periods could account, in part, for the drawdown of atmospheric CO2 into the ocean. Such an increase was inevitable due to the near elimination of shelf area for the burial of coral reef alkalinity. We present evidence, based on down-core measurements of benthic foraminiferal B/Ca and Mg/Ca from a core in the Weddell Sea, that the deep ocean carbonate ion concentration, [CO3 2-], was elevated by ~25 µmol/kg during each glacial period of the last 800 kyrs. The heterogeneity of the preservation histories in the different ocean basins reflects control of the carbonate chemistry of the deep glacial ocean in the Atlantic and Pacific by the changing ventilation and chemistry of Weddell Sea waters. These waters are more corrosive than interglacial northern sourced waters, but not as undersaturated as interglacial southern sourced waters. Our inferred increase in whole ocean alkalinity can be reconciled with reconstructions of glacial saturation horizon depth and the carbonate budget, if carbonate burial rates also increased above the saturation horizon as a result of enhanced pelagic calcification. The Weddell records display low [CO3 2-] during deglaciations and peak interglacial warmth, coincident with maxima in %CaCO3 in the Atlantic and Pacific Oceans. Should the burial rate of alkalinity in the more alkaline glacial deepwaters outstrip the rate of alkalinity supply, then pelagic carbonate production by the coccolithophores, at the end of the glacial maximum could drive a decrease in ocean [CO3 2-] and act to trigger the deglacial rise in pCO2.

Pleistocene rhyolithic tephra of ODP Leg 181 sites

Taupo Volcanic Zone (TVZ), in the North Island, New Zealand, is arguably the most active Quaternary rhyolitic system in the world. Numerous and widespread rhyolitic tephra layers, sourced from the TVZ, form valuable chronostratigraphic markers in onshore and offshore sedimentary sequences. In deep-sea cores from Ocean Drilling Program (ODP) Leg 181 Sites 1125, 1124, 1123 and 1122, located east of New Zealand, ca 100 tephra beds are recognised post-dating the Plio-Pleistocene boundary at 1.81 Ma. These tephras have been dated by a combination of magnetostratigraphy, orbitally tuned stable-isotope data and isothermal plateau fission track ages. The widespread occurrence of ash offshore to the east of New Zealand is favoured by the small size of New Zealand, the explosivity of the mainly plinian and ignimbritic eruptions and the prevailing westerly wind field. Although some tephras can be directly attributed to known TVZ eruptions, there are many more tephras represented within ODP-cores that have yet to be recognised in near-source on-land sequences. This is due to proximal source area erosion and/or deep burial as well as the adverse effect of vapour phase alteration and devitrification within near-source welded ignimbrites. Despite these difficulties, a number of key deep-sea tephras can be reliably correlated to equivalent-aged tephra exposed in uplifted marine back-arc successions of Wanganui Basin where an excellent chronology has been developed based on magnetostratigraphy, orbitally calibrated sedimentary cycles and isothermal plateau fission track ages on tephra. Significant Pleistocene tephra markers include: the Kawakawa, Omataroa, Rangitawa/Onepuhi, Kaukatea, Kidnappers-B, Potaka, Unit D/Ahuroa, Ongatiti, Rewa, Sub-Rewa, Pakihikura, Ototoka and Table Flat Tephras. Six other tephra layers are correlated between ODP-core sites but have yet to be recognised within onshore records. The identification of Pleistocene TVZ-sourced tephras within the ODP record, and their correlation to Wanganui Basin and other onshore sites is a significant advance as it provides: (1) an even more detailed history of the TVZ than can be currently achieved from the near-source record, (2) a high-resolution tephrochronologic framework for future onshore-offshore paleoenvironmental reconstructions, and (3) well-dated tephra beds correlated from the offshore ODP sites with astronomically tuned timescales provide an opportunity to critically evaluate the chronostratigraphic framework for onshore Plio-Pleistocene sedimentary sequences (e.g. Wanganui Basin, cf. Naish et al. (1998, doi:10.1016/S0277-3791(97)00075-9).

Salem Township (Mich.) residences, ca. 1874

Left to right: Res. of Daniel T. Birch, Sec. 31, Salem Tp. Mich.; Res. of J.L. Bennett, Sec. 15, Salem Tp. Mich.; Res. of Calvin Wheeler, Sec. 27, Salem Tp. Mich.; Res. of G.N.B. Renwick, Sec 27, Salem Tp. Mich.; Res. of Eli O. Smith, Sec 14, Salem Tp. Mich.; Res. of T.B. Gorton, Sec 3. Salem Tp. Mich. Publication information: Chicago, Ill. : Everts & Stewart, 1874.

Webster and Dexter Township (Mich.) residences, ca. 1874

Left to right: Res. of Samuel H. Ball, Sec 5, Webster Tp. Mich.; Res. of Alexander Mallion, Sec 28, Wester Tp., Mich.; Res. of J.B. Arms, Sec 4, Webster Tp. Mich.; Res. of Frederick Lee, Sec 30, Webster Tp. Mich.; Res. of Patrick Fleming, Sec 25, Dexter Tp. Mich.; Res. of W.. Brass, Sec 31, Webster Tp. Mich. Publication information: Chicago, Ill. : Everts & Stewart, 1874.

Augusta Township (Mich.) residences and business, ca. 1874

Left to right: Res. of Addison Osborn, Sec. 32, Augusta Tp. Mich.; Res. of Hiram McCarty, Sec. 9, Augusta Tp. Mich.; Res. & saw mill of Geo. Moffit, Sec. 28, Augusta Tp. Mich.; Res. of Mrs. W.M. McGraw, Stony Creek P.O., Augusta Tp. Mich.; Res. of J.B. Olcott, Sec. 7, Augusta Tp. Mich.; Res. of Peter Dansingburg, Sec. 18, Augusta Tp. Mich. Publication information: Chicago, Ill. : Everts & Stewart, 1874.

York, Saline, Ypsilanti, Lyndon, Sharon (Mich.) Township residences, ca. 1874

Left to right: Res. of C. Parsons, Saline, Mich.; Res. of D.B. Green, Ypsilanti, Mich.; Res. of Justus Corwin, Sec. 17, York Tp. Mich.; Res. of Robert Howlett, Sec. 20, Lyndon Tp. Mich.; Res. of Wm. Basom, Sec. 2, York Tp. Mich.; Res. of Jay Everett, Sec. 2, sharon Tp. Mich. Publication information: Chicago, Ill. : Everts & Stewart, 1874.

Lyndon, Saline and Ann Arbor (Mich.) residences and business, ca. 1874

Left to right: Woodside Res. of N.B. Cole, Ann Arbor, Mich. for sale; Res. of John K. Yocum, Sec. 30, Lyndon Tp. Mich; Corner Main & Liberty Sts., Ann Arbor, Mich.; C. Parsons, dealer in dry goods, boots & shoes, hats, caps &c., Saline Mich. Publication information: Chicago, Ill. : Everts & Stewart, 1874.

The gardeners labyrinth, or, A new art of gardening : wherein is laid down new and rare inventions and secrets of gardening not heretofore known : for sowing, planting, and setting all manner of roots, herbs, and flowers, both for the use of the kitchen garden, and a garden of pleasure ... /

"Reprinted for the first time since the edition dated 1652, from the copy now owned by Mrs. Rosetta E. Clarkson."--T.p. verso.

Hans, the Eskimo; his story of Arctic adventure with Kane, Hayes, and Hall,

Mode of access: Internet.

The diary of Dr. Thomas Cartwright, bishop of Chester; commencing at the time of his elevation to that see, August M.DC.LXXXVI,; and terminating with the visitation of St. Mary Magdalene college, Oxford, October M.DC.LXXXVII.

Mode of access: Internet.

The Spanish military nun; and, Revolt of the Tartars.

Added t.p.

Athenian letters: or, The epistolary correspondence of an agent of the king of Persia, residing at Athens during the Peloponnesian war. A new edition; to which is prefixed a geographical index. In two volumes. Illustrated with engravings, and a map of ancient Greece ...

The work of a group of English writers each letter being signed by an initial indicating the author, as follows. P.-Philip Yorke; C.-Charles Yorke; R.-G.H. Rooke; G.-John Green; W.-Daniel Wray; H.-Henry Heaton; E.-Wm. Heberden; O.-Henry Coventry; L.-John Lawry; T.-Catherine Talbot; B.-Thomas Birch; S.-Samuel Salter. The work was edited by Thomas Birch, the brothers Yorke having the largest share in the composition of the letters.