Prebiotic feeding elevates central brain derived neurotrophic factor, N-methyl-D-aspartate receptor subunits and D-serine

The influence of the gut microbiota on brain chemistry has been convincingly demonstrated in rodents. In the absence of gut bacteria, the central expression of brain derived neurotropic factor, (BDNF), and N-methyl-d-aspartate receptor (NMDAR) subunits are reduced, whereas, oral probiotics increase brain BDNF, and impart significant anxiolytic effects. We tested whether prebiotic compounds, which increase intrinsic enteric microbiota, also affected brain BDNF and NMDARs. In addition, we examined whether plasma from prebiotic treated rats released BDNF from human SH-SY5Y neuroblastoma cells, to provide an initial indication of mechanism of action. Rats were gavaged with fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS) or water for five weeks, prior to measurements of brain BDNF, NMDAR subunits and amino acids associated with glutamate neurotransmission (glutamate, glutamine, and serine and alanine enantiomers). Prebiotics increased hippocampal BDNF and NR1 subunit expression relative to controls. The intake of GOS also increased hippocampal NR2A subunits, and frontal cortex NR1 and d-serine. Prebiotics did not alter glutamate, glutamine, l-serine, l-alanine or d-alanine concentrations in the brain, though GOSfeeding raised plasma d-alanine. Elevated levels of plasma peptide YY (PYY) after GOS intake was observed. Plasma from GOS rats increased the release of BDNF from SH-SY5Y cells, but not in the presence of PYY antisera. The addition of synthetic PYY to SH-SY5Y cell cultures, also elevated BDNF secretion. We conclude that prebiotic-mediated proliferation of gut microbiota in rats, like probiotics, increases brain BDNF expression, possibly through the involvement of gut hormones. The effect of GOS on components of central NMDAR signalling was greater than FOS, and may reflect the proliferative potency of GOS on microbiota. Our data therefore, provide a sound basis to further investigate the utility of prebiotics in the maintenance of brain health and adjunctive treatment of neuropsychiatric disorders

The Earth: Plasma Sources, Losses, and Transport Processes

This paper reviews the state of knowledge concerning the source of magnetospheric plasma at Earth. Source of plasma, its acceleration and transport throughout the system, its consequences on system dynamics, and its loss are all discussed. Both observational and modeling advances since the last time this subject was covered in detail (Hultqvist et al., Magnetospheric Plasma Sources and Losses, 1999) are addressed

The palaeoecological record of Holocene environmental change in southwest Turkey

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Climatic, vegetation and cultural change in the eastern Mediterranean during the mid-Holocene environmental transition.

The eastern Mediterranean region witnessed changes in human culture of the highest importance between ~9000 and ~2500 cal. BP (7000—500 BC) and over the same time period was affected by very significant shifts in climate. Stable isotope data from lake and deep-sea sediment cores and from cave speleothems show an overall trend from a wetter to a drier climate during the mid Holocene. Superimposed on this trend were multicentennial oscillations in climate, with notable arid phases occurring around 5300—5000 BP, 4500—3900 BP, and 3100—2800 BP (all ages are expressed in calibrated/ calendar years). These phases coincide with major archaeological transitions across the eastern Mediterranean region (Chalcolithic to early Bronze Age, EBA to MBA, and LBA to Iron Age) implying that environmental stress or opportunity may have acted as a pacemaker for cultural change and re-organisation. We use14C and δ13C analysis of archaeobotanical samples from two protohistoric sites in Syria to illustrate the linkage between water availability, climate and cultural change during the third and second millennia BC. Specific societal responses to environmental change were not predictable in advance, but resulted instead from contingent processes involving antecedent conditions, human choice and adaptive strategies. Pollen analysis highlights how changes in climate were coupled to increasing human impacts to transform the region’s landscapes. Initial human-induced land-cover transformation commonly took place during Bronze Age times, sometimes coinciding with phases of drier climate, although the pattern and precise timing varied between sites. Changes in climate between the early and late Holocene thus helped to transform eastern Mediterranean landscape ecologies and human cultures, but in complex, non-deterministic ways.</jats:p

A 500 yr speleothem-derived reconstruction of late autumn-winter precipitation, northeast Turkey

A verified instrumental calibration of annually resolved δ18O for a stalagmite from Gümüşhane in northeast Turkey is presented and cross-validated using a ‘leave-one-out’ technique. The amount of late autumn to winter precipitation is negatively correlated with stalagmite δ18O between AD 1938 and 2004. The observed relationship is extrapolated back to ~ AD 1500 leading to the first long winter precipitation reconstruction for this region. Modern day October to January precipitation is linked to pressure fields in Western Russia. Anomalously lower reconstructed rainfall is recorded in AD 1540–1560 at which time higher pressure over the Caspian Sea region is inferred

Measuring airway dimensions during bronchoscopy using anatomical optical coherence tomography

Airway dimensions are difficult to quantify bronchoscopically because of optical distortion and a limited ability to gauge depth. Anatomical optical coherence tomography (aOCT), a novel imaging technique, may overcome these limitations. This study evaluated the accuracy of aOCT against existing techniques in phantom, excised pig and in vivo human airways. Three comparative studies were performed: 1) micrometer-derived area measurements in 10 plastic tubes were compared with aOCT-derived area; 2) aOCT-derived airway compliance curves from excised pig airways were compared with curves derived using an endoscopic technique; and 3) airway dimensions from the trachea to subsegmental bronchi were measured using aOCT in four anaesthetised patients during bronchoscopy and compared with computed tomography (CT) measurements. Measurements in plastic tubes revealed aOCT to be accurate and reliable. In pig airways, aOCT-derived compliance measurements compared closely with endoscopic data. In human airways, dimensions measured with aOCT and CT correlated closely. Bland - Altman plots showed that aOCT diameter and area measurements were higher than CT measurements by 7.6% and 15.1%, respectively. Airway measurements using aOCT are accurate, reliable and compare favourably with existing imaging techniques. Using aOCT with conventional bronchoscopy allows real-time measurement of airway dimensions and could be useful clinically in settings where knowledge of airway calibre is required

Elastic properties of the central airways in obstructive lung diseases measured using anatomical optical coherence tomography

Rationale: Our understanding of how airway remodeling affects regional airway elastic properties is limited due to technical difficulties in quantitatively measuring dynamic, in vivo airway dimensions. Such knowledge could help elucidate mechanisms of excessive airway narrowing. Objectives: To use anatomical optical coherence tomography (aOCT) to compare central airway elastic properties in control subjects and those with obstructive lung diseases. Methods: After bronchodilation, airway lumen area (Ai) was measured using aOCT during bronchoscopy in control subjects (n = 10) and those with asthma (n = 16), chronic obstructive pulmonary disease (COPD) (n = 9), and bronchiectasis (n = 8). Ai was measured in each of generations 0 to 5 while airway pressure was increased from -10 to 20 cm H2O. Airway compliance (Caw) and specific compliance (sCaw) were derived from the transpulmonary pressure (PL) versus Ai curves. Measurements and Main Results: Caw decreased progressively as airway generation increased, but sCaw did not differ appreciably across the generations. In subjects with asthma and bronchiectasis, Caw and sCaw were similar to control subjects and the PL-Ai curves were left-shifted. No significant differences were observed between control and COPD groups. Conclusions: Proximal airway elastic properties are altered in obstructive lung diseases. Although central airway compliance does not differ from control subjects in asthma, bronchiectasis, or COPD, Ai is lower in asthma and the PL-Ai relationship is left-shifted in both asthma and bronchiectasis, suggesting that airways are maximally distended at lower inflating pressures. Such changes reflect alteration in the balance between airway wall distensibility and radial traction exerted on airways by surrounding lung parenchyma favoring airway narrowing