bluuebunny/crossref_metadata_2025 huggingface dataset:
Analogues of cholecystokinin methylated in the side chain of carboxyterminal phenylalanine
Authors: Hlaváček Jan , Pírková Jana , Majer Pavel , Žertová Miroslava , Maletínská Lenka , Slaninová Jiřina
Published: August 2009

In the course of our study on cholecystokinin (CCK) a series of Boc-CCK-7 was synthesized. Their carboxyterminal part was modified by phenylalanine derivatives containing 2 or 4 and 2,6 or 2,4,6 methylated aromatic side-chain. During the synthesis, the racemic phenylalanine derivatives were used and peptides containing either L- or D- methylated phenylalanine were separated using a preparative HPLC. Gall bladder contraction, anorectic, sedative and analgetic bioassays of these analogues revealed that all of them behaved as CCK-8 agonists. While the analogues containing L-form of the methylated phenylalanines had almost the same potency (80% - 130%) in comparison to CCK-8, the presence of the D-form decreased the biological activity of corresponding analogues to 8 – 62% of the CCK-8 potency. These results are in agreement with the suggestion that phenylalanine residue in C-terminus takes part in biological activity transduction only.
Synthesis of some new N-substituted quinolimides with antibacterial activities
Authors: Mohamed Thana A. , Kandeel Maymona M. , Awad Ibrahim M. A. , Youssef Mohamed Salah K.
Published: August 2009

Article without abstract
Synthesis and circular dichroism characterization of new optically active transition metal complexes:M[(-)bdtp]3, M = Co3+, Rh3+, Ir3+
Authors: Biscarini Paolo
Published: August 2009

The chiral octahedral diastereoisomeric tris[(-)cyclic O,O’,1(R),2(R)(-)dimethylethylene dithiophosphato]metal(III) complexes, M[(-)bdtp]3, M(III) = Co, Rh, Ir, have been obtained stereoselectively in the Λ or Δ absolute configuration at the metal centre. The formation reaction and the characterization of the obtained complexes have been followed by circular dichroism spectroscopy. The complexes prove optically labile in various solvents. A configuration inversion has been observed in all complexes giving diastereoisomeric equilibria Λ(R,R)(R,R)(R,R) = Δ(R,R)(R,R)(R,R) with an excess of one form, occasionally stabilized by the solvent.
Circular dichroism measurements in the VUV
Authors: Gedanken Aharon
Published: August 2009

The extension of circular dichroism measurements into the VUV region was motivated by the need to provide supplementary techniques to the absorption studies lacking rotational and vibrational structure. CD as one of these techniques is determined by selection rules which differ from those in absorption and thus enables the assignment of excited electronic states. Another application of VUVCD measurements is the use of correlation between the sign of the CD signal and the absolute configuration to formulate sector rules of chromophores absorbing only in the VUV. In this review we will present results obtained on our home-made instrument capable of measuring CD signal down to 150 nm. These applications of VUVCD will be demonstrated in systems such as the oxirane chromophore, the methylenecyclohexene chromophore and the amine chromophore. The role of singlet-triplet transitions and their contribution to CD and ORD will also be discussed.
Excited-state chiral discrimination in aqueous solutions of lanthanide(III): 2,6-pyridinedicarboxylate complexes
Authors: Wu Shuguang , Bedard Thomas C. , Riehl James P.
Published: August 2009

Addition of resolved-Ru(phenanthroline)32+ to aqueous solutions of racemic complexes of Ln(2,6-pyridinedicarboxylate)33- (where Ln = Eu(III) and Tb(III) results in efficient quenching of lanthanide emission. The terbium complex is quenched more than the europium complex illustrating the importance of electronic overlap. The emission is also circularly polarized indicating that the quenching mechanism is enantioselective. Comparison with previous data allows for the identification of the enantiomer in excess, and, thus, of the favored enantioselective energy transfer pair.
Euthanasia and eudaimonia
Authors: Shaw D M
Published: August 2009

This paper re-evaluates euthanasia and assisted suicide from the perspective of eudaimonia, the ancient Greek conception of happiness across one’s whole life. It is argued that one cannot be said to have fully flourished or had a truly happy life if one’s death is preceded by a period of unbearable pain or suffering that one cannot avoid without assistance in ending one’s life. While death is to be accepted as part of life, it should not be left to nature to dictate the way we die, and it is fundamentally unjust to grant people liberal latitude in how they live their lives while granting them little control over the conclusion of their life narratives. Three objections to this position are considered and rejected; the paper also offers an explanation of why we think killing can be a benefit. Ultimately, euthanasia may be necessary in some cases in order to achieve eudaimonia.
Amplified fragment length polymorphism analysis reveals high genetic variation in the Ouachita Mountain endemic Carex latebracteata (Cyperaceae)
Authors: Ford Bruce A. , Worley Anne C. , Naczi Robert F. C. , Ghazvini Habibollah
Published: August 2009

Species with limited geographic ranges are often of conservation concern because they may possess low levels of genetic variability and thus have a reduced ability to respond to stochastic events. As a consequence, an important conservation strategy is to maximize a species’ adaptive potential by preserving natural levels of genetic variation. With this goal in mind, we assessed genetic variation within and among six populations of the Ouachita Mountain endemic Carex latebracteata Waterfall using 653 amplified fragment length polymorphism (AFLP) loci. Indices of genetic variation [% polymorphic loci, expected heterozygosity (HE), population differentiation (ΦPT)] were most consistent with an outcrossing or mixed mating system despite an inflorescence morphology that seems conducive to self-pollination. An analysis of molecular variance (AMOVA) showed that >80% of the variation occurred within populations, suggesting high levels of gene flow. The close geographic proximity of most populations, which are often adjacent to streams, may facilitate long-distance seed dispersal and help to maintain high intra-population genetic variation. Conservation strategies focused on maintaining the ecological integrity of rivers and streams, and the provision of naturally vegetated buffers would likely assist in the conservation of this and other Ouachita Mountain endemics.
Opportunistic heterotrophy in gametophytes of the homosporous fernCeratopteris richardii
Authors: Alongi Deborah A. , Hill Jeffrey P. , Germino Matthew J.
Published: August 2009

Fern gametophytes are extremely shade-tolerant, potentially existing for long periods under conditions of extreme light limitation. Many previous studies have demonstrated an increase in gametophyte growth and incidence of spontaneous transition to sporophyte morphology (apogamy) under culture on media containing exogenous sugar. However, these studies did not verify sugar uptake or quantify relative growth on media containing different sugar types. Here, we examine the extent of heterotrophy and underlying mechanisms of sugar transport in photosynthetic gametophytes of the fern Ceratopteris richardii Brongn. Exogenous sugar uptake, growth, and sugar transport were evaluated with assays of exogenous glucose depletion, experimental culture of gametophytes under different sugar and light conditions, and bioinformatic approaches. The glucose from the growth media was significantly depleted by gametophytes growing under all conditions, especially those in the dark compared with those exposed to higher light. Gametophyte area increased similarly when cultured on equimolar concentrations of either glucose or the disaccharide sucrose, likely due to preferential uptake of one of the monomers of sucrose. Although at least one gene with similarity to sucrose transporters is expressed in germinating spores, our results suggest a reliance on monosaccharide transport for exogenous sugar uptake. Glucose assimilation in both light and dark conditions constitutes nutritional opportunism and may enhance gametophyte survival in very low light.
Aegilops sharonensis:Origin, genetics, diversity, and potential for wheat improvement
Authors: Olivera Pablo D. , Steffenson Brian J.
Published: August 2009

Aegilops sharonensis  Eig (Sharon goatgrass; section Sitopsis) is an annual diploid grass species growing endemically in the coastal plains of Israel and southern Lebanon. It is a wild relative of wheat, with a genome closely related to the B genome of cultivated bread wheat. With the most limited distribution of any species in the genus Aegilops, Ae. sharonensis is rapidly losing its habitats, owing to the combined effects of modern agricultural intensification and expansion of urban and industrial areas. Aegilops sharonensis is known to be a rich source of genes providing resistance to important wheat diseases and abiotic stresses, but it has not been widely exploited. The presence of gametocidal genes that control preferential transmission of chromosome 4Sshincreases the difficulty of introgressing genes from Ae. sharonensis into wheat. However, successful introgression of the genes for resistance to leaf rust, stripe rust, and powdery mildew has been achieved. Studies on genetic and phenotypic diversity indicated that Ae. sharonensis is a highly diverse species, comparable with others that have a wider geographic distribution and more variable environments. Targeting the regions and sites with the highest diversity in Ae. sharonensis will facilitate the capture of the greatest variability and also the identification of novel and diverse genes for wheat improvement.
Isolation-by-distance within naturally established populations of European beech (Fagus sylvatica)
Authors: Chybicki Igor J. , Trojankiewicz Magdalena , Oleksa Andrzej , Dzialuk Artur , Burczyk Jaroslaw
Published: August 2009

In plants, the magnitude of seed and pollen dispersal plays a pivotal role in shaping genetic structure of populations. Restricted dispersal of genes can stimulate the increase of inbreeding as well as spatial clustering of relatives. These phenomena are explained by the theory of isolation-by-distance. Because of its biology, European beech ( Fagus sylvatica L.) seems to be susceptible to isolation-by-distance. However, to date fine-scale effects, including biparental inbreeding and a spatial genetic structure are not fully recognized for this species. In this study, two populations of European beech were investigated, both representing a dense beech forest, typical for Central Europe. Using nine microsatellite markers and a recently developed method, we found a significant level of biparental inbreeding in both populations. Spatial autocorrelation analysis revealed that both populations exhibit clustering of related individuals up to 40 m. The observed spatial genetic structure fit well to the log-linear regression model. Thus, results confirmed our hypothesis of the presence of the isolation-by-distance effect. Furthermore, based on these results we inferred a dispersal mode, both for seeds and pollen; in particular, seed dispersal was 10–100 times more restricted than pollen flow, although a significant portion of short-distance pollinations responsible for biparental inbreeding cannot be excluded.
Plankton Size Spectra in Relation to Ecosystem Productivity, Size, and Perturbation
Authors: Sprules W. Gary , Munawar M.
Published: August 2009

Quantification and comparisons of the structure of open-water plankton communities from 25 inland lakes of Ontario, from the Laurentian Great Lakes Superior, Huron, St. Clair, Ontario, and Erie, and from the Central Gyre in the North Pacific Ocean were made on the basis of the normalized biomass size spectrum. Residual variation around the fitted straight lines (corresponding to a theoretical steady state) was least for the large, oligotrophic Lake Superior and the North Pacific Gyre and greatest for eutrophic Saginaw Bay and shallow Lake Erie, suggesting progressive departure from steady-state conditions with increasing system productivity. The slopes of the normalized spectra decrease with increasing eutrophy, indicating that nannoplankton abundances are similar in all communities studied, but that associated zooplankton abundances vary by 2.5 orders of magnitude. Our results suggest that parameterization of particle-size models for prediction of potential fish production must be adjusted according to the size and productivity of the ecosystem, and that routine monitoring of communities by the normalized biomass spectrum could provide early warning of nutrient or toxic stress in aquatic ecosystems.
Analysis of the Phytoplankton Composition of 95 Labrador Lakes, with Special Reference to Natural and Anthropogenic Acidification
Authors: Earle J. Chris , Duthie Hamish C. , Scruton David A.
Published: August 2009

Phytoplankton abundances and accompanying morphometric, physical, and chemical data from 95 Labrador lakes were subjected to statistical analysis to determine the structure of the phytoplankton communities and to relate environmental factors to the patterns observed. Factor analysis of the 22 measured physical and chemical variables reduced the data to six derived environmental factors: hardness, dystrophy, lake size, salinity, oligotrophy, and seasonality. The analysis showed that the low-pH lakes are associated with dystrophy and hence are likely to be naturally acidic. There was no evidence of anthropogenic acidification. Eight groups of co-occurring taxa were recognized from the data set, and all but two exhibited relatively consistent habitat preferences. It was suggested that the groups represent "species associations" in the sense that each group contains taxa that occur together because of similar requirements for a specific set of environmental conditions. Several lake types were identified as potentially influencing the distribution of phytoplankton in Labrador: small, dystrophic lakes; clear, softwater lakes; clear, hardwater lakes; large, hardwater lakes; and coloured, hardwater lakes.
Three-Dimensional Distribution of Winter Stonefly Nymphs, Allocapnia pygmaea, within the Substrate of a Southern Ontario River
Authors: Pugsley C W. , Hynes H. B. N.
Published: August 2009

Changes in the three-dimensional distribution patterns of stonefly nymphs, Allocapnia pygmaea, beneath the streambed in the Speed River, southern Ontario, were monitored throughout their 1-yr life cycle using 270 colonization chambers. These were filled with organism-free, sieved stream gravel and buried in vertical groups of three, at three depth intervals, in three trenches positioned across a riffle. Nymphs were present throughout the year. Seasonal changes in the distribution pattern of nymphs indicated that they were able to move beneath the streambed in both the horizontal and vertical planes. Nymphs were most abundant at depth during the summer diapause, but moved up to the surface once diapause had been broken in the autumn. There was no evidence of any bankwards migration of nymphs prior to emergence. We have therefore confirmed in detail previous suggestions that stream insects move freely into and out of the hyporheic, using it as a refuge from adverse conditions on the streambed. Stream ecologists should therefore be aware of the possibilities of movement to and from the hyporheic when working with benthic invertebrates.
Relationships Between Stream and Intragravel Temperatures in Coastal Drainages, and Some Implications for Fisheries Workers
Authors: Shepherd Bruce G. , Hartman Gordon F. , Wilson William J.
Published: August 2009

By a depth of 10 cm into the streambed, water temperatures are likely to be different from those in the open water of the stream. Combined results from three independent studies on disparate streams on the Pacific Northwest coast indicated that there are widespread similarities in the thermal behavior of intragravel water. In general, the thermal mass of the substrate causes parallel but lagged and buffered heating and cooling trends in infiltration-source intragravel water compared with surface water. Intragravel mean daily temperatures were generally 0.5–1.0 °C warmer in winter and 0.5–1.5 °C cooler in summer, with cross-overs around March and October; intragravel daily maximum temperatures could be up to 6 °C different in summer (a difference of 4 °C was common). The degree of difference showed considerable site-specific variation, and potentially can be affected by several factors. Such intragravel temperature differences have implications for those involved in salmonid egg incubation and fry emergence studies, enhancement projects, benthic invertebrate research, and environmental impact assessments.
MIMO DS-BPAM UWB SYSTEM WITH SRAKE RECEIVER OVER MULTIPATH FADING CHANNELS
Authors: BAI ZHIQUAN , XU YUANQUAN , LI XIAOTONG , LI RONGKAI , YUAN DONGFENG , KWAK KYUNGSUP
Published: August 2009

In this paper, we investigate the multiple input multiple output (MIMO) direct sequence bipolar pulse amplitude modulation (DS-BPAM) ultra wideband (UWB) system over indoor multipath fading channels based on the research of Alamouti space-time block codes (STBC) and DS-BPAM UWB system. Selective Rake (SRake) receiver is employed in this paper in order to deal with the multipath effects. Theoretical bit error probability of the MIMO DS-BPAM UWB system with SRake receiver is derived. Simulation results of the MIMO DS-BPAM UWB system with SRake receiver and conventional coherent receiver over multipath fading channels are provided. The results show the efficiency of the MIMO DS-BPAM UWB system with SRake receiver.
PCB INDUCTOR IMPEDANCE CALCULATION BASED ON WAVELET-MoM
Authors: DONG HUI , ZHU YI-SHENG , CHEN WAI-KAI
Published: August 2009

Planar PCB inductors, being printed directly on the PCB board, are employed in various electronic systems. The resistance and inductance of a square PCB inductor are calculated in this paper. For this a multiconductor transmission-line model is constructed and its coupling integral equations are given. These equations are solved by wavelet-MoM, in which a [0, 1] Coifman intervallic scarlet is used. Finally, the inductance and resistance versus frequency plots are presented.
Evolution of Genomic Imprinting: Insights from Marsupials and Monotremes
Authors: Renfree Marilyn B. , Hore Timothy A. , Shaw Geoffrey , Marshall Graves Jennifer A. , Pask Andrew J.
Published: August 2009

Parent-of-origin gene expression (genomic imprinting) is widespread among eutherian mammals and also occurs in marsupials. Most imprinted genes are expressed in the placenta, but the brain is also a favored site. Although imprinting evolved in therian mammals before the marsupial-eutherian split, the mechanisms have continued to evolve in each lineage to produce differences between the two groups in terms of the number and regulation of imprinted genes. As yet there is no evidence for genomic imprinting in the egg-laying monotreme mammals, although these mammals also form a placenta (albeit short-lived) and transfer nutrients from mother to embryo. Therefore, imprinting was not essential for the evolution of the placenta and its importance in nutrient transfer but the elaboration of imprinted genes in marsupials and eutherians is associated with viviparity. Here we review the recent analyses of imprinted gene clusters in marsupials and monotremes, which have served to shed light on the origin and evolution of imprinting mechanisms in mammals.
Genetics of Athletic Performance
Authors: Ostrander Elaine A. , Huson Heather J. , Ostrander Gary K.
Published: August 2009

Performance enhancing polymorphisms (PEPs) are examples of natural genetic variation that affect the outcome of athletic challenges. Elite athletes, and what separates them from the average competitor, have been the subjects of discussion and debate for decades. While training, diet, and mental fitness are all clearly important contributors to achieving athletic success, the fact that individuals reaching the pinnacle of their chosen sports often share both physical and physiological attributes suggests a role for genetics. That multiple members of a family often participate in highly competitive events, such as the Olympics, further supports this argument.

In this review, we discuss what is known regarding the genes and gene families, including the mitochondrial genome, that are believed to play a role in human athletic performance. Where possible, we describe the physiological impact of the critical gene variants and consider predictions about other potentially important genes. Finally, we discuss the implications of these findings on the future for competitive athletics.
Genomic Analyses of Sex Chromosome Evolution
Authors: Wilson Melissa A. , Makova Kateryna D.
Published: August 2009

Sex chromosomes have evolved multiple times in many taxa. The recent explosion in the availability of whole genome sequences from a variety of organisms makes it possible to investigate sex chromosome evolution within and across genomes. Comparative genomic studies have shown that quite distant species may share fundamental properties of sex chromosome evolution, while very similar species can evolve unique sex chromosome systems. Furthermore, within-species genomic analyses can illuminate chromosome-wide sequence and expression polymorphisms. Here, we explore recent advances in the study of vertebrate sex chromosomes achieved using genomic analyses.
Global Legal Pluralism
Authors: Michaels Ralf
Published: August 2009

Some challenges of legal globalization closely resemble those formulated earlier for legal pluralism: the irreducible plurality of legal orders, the coexistence of domestic state law with other legal orders, the absence of a hierarchically superior position transcending the differences. This review discusses how legal pluralism engages with legal globalization and how legal globalization utilizes legal pluralism. It demonstrates how several international legal disciplines—comparative law, conflict of laws, public international law, and European Union law—have slowly begun to adopt some ideas of legal pluralism. It shows how traditional themes and questions of legal pluralism—the definition of law, the role of the state, of community, and of space—are altered under conditions of globalization. It addresses interrelations between different legal orders and various ways, both theoretical and practical, to deal with them. And it provides an outlook on the future of global legal pluralism as theory and practice of global law.
Protease activation during in vivo pancreatitis is dependent on calcineurin activation
Authors: Shah Ahsan U. , Sarwar Amna , Orabi Abrahim I. , Gautam Samir , Grant Wayne M. , Park Alexander J. , Shah Adnan U. , Liu Jun , Mistry Pramod K. , Jain Dhanpat , Husain Sohail Z.
Published: August 2009

The premature activation of digestive proenzymes, specifically proteases, within the pancreatic acinar cell is an early and critical event during acute pancreatitis. Our previous studies demonstrate that this activation requires a distinct pathological rise in cytosolic Ca2+. Furthermore, we have shown that a target of aberrant Ca2+in acinar cells is the Ca2+/calmodulin-dependent phosphatase calcineurin (PP2B). In this study, we hypothesized that PP2B mediates in vivo protease activation and pancreatitis severity. To test this, pancreatitis was induced in mice over 8 h by administering hourly intraperitoneal injections of the cholecystokinin analog caerulein (50 μg/kg). Treatment with the PP2B inhibitor FK506 at 1 and 8 h after pancreatitis induction reduced trypsin activities by greater than 50% ( P < 0.005). Serum amylase and IL-6 was reduced by 86 and 84% relative to baseline ( P < 0.0005) at 8 h, respectively. Histological severity of pancreatitis, graded on the basis of pancreatic edema, acinar cell vacuolization, inflammation, and apoptosis, was reduced early in the course of pancreatitis. Myeloperoxidase activity from both pancreas and lung was reduced by 93 and 83% relative to baseline, respectively ( P < 0.05). These data suggest that PP2B is an important target of the aberrant acinar cell Ca2+rise associated with pathological protease activation and pancreatitis.
Mechanisms underlying modulation of monocarboxylate transporter 1 (MCT1) by somatostatin in human intestinal epithelial cells
Authors: Saksena Seema , Theegala Saritha , Bansal Nikhil , Gill Ravinder K. , Tyagi Sangeeta , Alrefai Waddah A. , Ramaswamy Krishnamurthy , Dudeja Pradeep K.
Published: August 2009

Somatostatin (SST), an important neuropeptide of the gastrointestinal tract has been shown to stimulate sodium chloride absorption and inhibit chloride secretion in the intestine. However, the effects of SST on luminal butyrate absorption in the human intestine have not been investigated. Earlier studies from our group and others have shown that monocarboxylate transporter (MCT1) plays an important role in the transport of butyrate in the human intestine. The present studies were undertaken to examine the effects of SST on butyrate uptake utilizing postconfluent human intestinal epithelial Caco2 cells. Apical SST treatment of Caco-2 cells for 30–60 min significantly increased butyrate uptake in a dose-dependent manner with maximal increase at 50 nM (∼60%, P < 0.05). SST receptor 2 agonist, seglitide, mimicked the effects of SST on butyrate uptake. SST-mediated stimulation of butyrate uptake involved the p38 MAP kinase-dependent pathway. Kinetic studies demonstrated that SST increased the maximal velocity ( Vmax) of the transporter by approximately twofold without any change in apparent Michaelis-Menten constant ( Km). The higher butyrate uptake in response to SST was associated with an increase in the apical membrane levels of MCT1 protein parallel to a decrease in the intracellular MCT1 pool. MCT1 has been shown to interact specifically with CD147 glycoprotein/chaperone to facilitate proper expression and function of MCT1 at the cell surface. SST significantly enhanced the membrane levels of CD147 as well as its association with MCT1. This association was completely abolished by the specific p38 MAP kinase inhibitor, SB203580. Our findings demonstrate that increased MCT1 association with CD147 at the apical membrane in response to SST is p38 MAP kinase dependent and underlies the stimulatory effects of SST on butyrate uptake.
Extracellular activation of arginase-1 decreases enterocyte inducible nitric oxide synthase activity during systemic inflammation
Authors: Miki Keita , Kumar Abhai , Yang Runkuan , Killeen Meaghan E. , Delude Russell L.
Published: August 2009

Liver dysfunction secondary to severe inflammation is associated with the release of enzymes normally sequestered within hepatocytes. The purpose of these studies was to test the hypothesis that these enzymes are released, at least in part, to modulate potentially deleterious inflammatory processes in distant tissues like the gut. Human Caco-2BBeenterocyte-like cells were exposed to cytomix (IFN-γ, TNF-α, and IL-1β) in the absence or presence of human liver cytosol (LC). Nitric oxide (NO•) and inducible nitric oxide synthase (iNOS) protein production were measured by the Griess assay and Western analysis, respectively. Cytomix induced the expression of iNOS and release of NO•. LC protein (400 μg/ml) added to the basal compartment but not apical compartment completely blocked the release of NO•but only slightly decreased the magnitude of iNOS protein induction. Ultrafiltration and ultracentrifugation studies demonstrated that microsome-associated arginase-1 activity was the iNOS-suppressing activity in LC. Liver arginase required activation by a <10-kDa factor that was present in supernatants of cytomix-stimulated cells. The selective iNOS inhibitor l- N6-(1-iminoethyl)-lysine·2HCl prevented production of this factor. The biotin switch assay detected increased S-nitrosylation of arginase-1 after incubation with supernatants from immunostimulated Caco-2 cells. Serum from endotoxemic mice contained significantly greater arginase activity compared with serum from control mice. Furthermore, the ratio of mucosal monomeric to dimeric iNOS increased in endotoxemic mice compared with controls. Thus reciprocal activation of arginase-1 and modulation of mucosal iNOS activity may be protective because it would be expected to decrease NO•-dependent intestinal barrier dysfunction on that basis.
Effects of hypercapnia with and without acidosis on hypoxic pulmonary vasoconstriction
Authors: Ketabchi Farzaneh , Egemnazarov Bakytbek , Schermuly Ralph T. , Ghofrani Hossein A. , Seeger Werner , Grimminger Friedrich , Shid-Moosavi Mostafa , Dehghani Gholam A. , Weissmann Norbert , Sommer Natascha
Published: August 2009

Acute respiratory disorders and permissive hypercapnic strategy may lead to alveolar hypoxia and hypercapnic acidosis. However, the effects of hypercapnia with or without acidosis on hypoxic pulmonary vasoconstriction (HPV) and oxygen diffusion capacity of the lung are controversial. We investigated the effects of hypercapnic acidosis and hypercapnia with normal pH (pH corrected with sodium bicarbonate) on HPV, capillary permeability, gas exchange, and ventilation-perfusion matching in the isolated ventilated-perfused rabbit lung. No alteration in vascular tone was noted during normoxic hypercapnia with or without acidosis compared with normoxic normocapnia. Hypercapnia with normal pH resulted in a transient increase in HPV during the course of consecutive ventilation maneuvers, whereas hypercapnic acidosis increased HPV over time. Hypercapnic acidosis decreased exhaled NO during hypoxia more than hypercapnia with normal pH and normocapnia, whereas intravascular NO release was unchanged. However, inhibition of NO synthesis by nitro-l-arginine (l-NNA) resulted in a loss of the increased HPV caused by hypercapnic acidosis but not that caused by hypercapnia with normal pH. Furthermore, capillary permeability increased during hypoxic hypercapnia with normal pH but not hypoxic hypercapnic acidosis. This effect was NO-dependent because it disappeared during l-NNA administration. Ventilation-perfusion matching and arterial Po2 were improved according to the strength of HPV in hypercapnia compared with normocapnia during Tween nebulization-induced lung injury. In conclusion, the increased HPV during hypercapnic acidosis is beneficial to lung gas exchange by improving ventilation-perfusion matching and preserving the capillary barrier function. These effects seem to be linked to NO-mediated pathways.
Rat alveolar type I cells proliferate, express OCT-4, and exhibit phenotypic plasticity in vitro
Authors: Gonzalez Robert F. , Allen Lennell , Dobbs Leland G.
Published: August 2009

Alveolar type I (TI) cells are large, squamous cells that cover 95–99% of the internal surface area of the lung. Although TI cells are believed to be terminally differentiated, incapable of either proliferation or phenotypic plasticity, TI cells in vitro both proliferate and express phenotypic markers of other differentiated cell types. Rat TI cells isolated in purities of >99% proliferate in culture, with a sixfold increase in cell number before the cells reach confluence; >50% of the cultured TI cells are Ki67+. At cell densities of 1–2 cells/well, ∼50% of the cells had the capacity to form colonies. Under the same conditions, type II cells do not proliferate. Cultured TI cells express RTI40 and aquaporin 5, phenotypic markers of the TI cell phenotype. By immunofluorescence, Western blotting, and Q-PCR, TI cells express OCT-4A (POU5F1), a transcription factor associated with maintenance of the pluripotent state in stem cells. Based on the expression patterns of various marker proteins, TI cells are distinct from either of two recently described putative pulmonary multipotent cell populations, the bronchoalveolar stem cell or the OCT-4+ stem/progenitor cell. Although TI cells in adult rat lung tissue do not express either surfactant protein C (SP-C) or CC10, respective markers of the TII and Clara cell phenotypes, in culture TI cells can be induced to express both SP-C and CC10. Together, the findings that TI cells proliferate and exhibit phenotypic plasticity in vitro raise the possibility that TI cells may have similar properties in vivo.
Expression Levels of Insulin-Like Growth Factor-1 and Multidrug Resistance-Associated Protein-1 Indicate Poor Prognosis in Patients with Gastric Cancer
Authors: Ge Jie , Chen Zhikang , Wu Shaobin , Chen Jinxiang , Li Xiaoli , Li Jun , Yin Jiye , Chen Zihua
Published: August 2009

Background/Objectives: Insulin-like growth factor-1 receptor (IGF-1R) displays a key role in tumor transformation and metastasis. It also makes tumor cells more resistant to chemotherapy. The aim of this study was to investigate the correlation between IGF-1R and multidrug resistance-associated protein-1 (MRP-1), and the clinical significance of their expression in gastric carcinoma (GC). Methods: IGF-1R and MRP-1 expressed in 113 specimens were detected by immunohistochemistry. The correlation between IGF-1R and MRP-1 expression was determined. In addition, the association of their expression with clinicopathological features and survival data of GC was also analyzed. Results: IGF-1R (75.2%) and MRP-1 (69.0%) were frequently expressed in GC. IGF-1R was associated with tumor size, quantity of stroma, depth of wall invasion, lymph node metastasis, TNM stages and differentiation status of GC (p < 0.05). MRP-1 was associated with tumor size, quantity of stroma, lymph node metastasis, distant metastasis and TNM stages (p < 0.05). IGF-1R over-expression positively correlated with MRP-1 over-expression (rp = 0.39, p < 0.01). IGF-1R and MPR-1 over-expression were correlated with poor prognosis of GC (p < 0.01). 102 patients receiving adjuvant FOLFOX-4 chemotherapy who co-expressed IGF-1R/MRP-1 had poor prognosis (p < 0.05). Conclusions: The levels of co-expression of IGF-1R/MRP-1 in GC may predict the therapeutic effect of chemotherapy and prognosis of GC.
Increased Renal Proximal Convoluted Tubule Transport Contributes to Hypertension in Cyp4a14 Knockout Mice
Authors: Quigley Raymond , Chakravarty Sumana , Zhao Xueying , Imig John D. , Capdevila Jorge H.
Published: August 2009

Background/Aims:Disrupting the enzyme Cyp4a14 in mice leads to hypertension, which is more severe in the male mice and appears to be due to androgen excess. Because the Cyp4a14 enzyme is located in the proximal tubule of the kidney, we hypothesized that there could be dysregulation of transport in this segment that could contribute to the hypertension. Methods: Wild-type (SV/129) mice and mice that had targeted disruption of the Cyp4a14 gene were studied. Proximal convoluted tubules (PCT) from knockout and wild-type mice were dissected and perfused in vitrofor measurement of volume absorption (JV). Expression of the sodium-hydrogen exchanger 3 (NHE3), the predominant transporter responsible for sodium transport in this segment, was measured by immunoblot. Renal vascular (afferent arteriole) responses to angiotensin and endothelin were also measured. Results: PCT volume absorption was elevated in tubules from the Cyp4a14 knockout mice as compared to the wild-type mice. Brush border membrane NHE3 expression was almost 2-fold higher in Cyp4a14 knockout mice than in wild-type mice. No difference was found in the afferent arteriolar response. Conclusion: Thus, hypertension in the Cyp4a14 knockout mice appears to be driven by excessive fluid reabsorption in the proximal tubule, which is secondary to overexpression of NHE3.
Nucleus Caudalis Dorsal Root Entry Zone Lesions: A Clinical-Radiographic Case Report
Authors: Samreen Naziya , Friedman William A.
Published: August 2009

Objective: The purpose of this paper is to report on a case of a successful dorsal root entry zone procedure done for the treatment of postherpetic neuralgia and to provide unique MRI documentation outlining the precise location of the surgical lesion. Clinical Presentation: A 79-year-old female presented with postherpetic neuralgia in the left V1 distribution following a herpes zoster infection in that area 7 weeks earlier. She described the pain as constant, burning, aching, and throbbing, rating it as a 10 on a scale from 1 to 10. Prior to surgery, the patient was on large doses of narcotics, which were causing her to be severely somnolent. Intervention or Technique: A dorsal root entry zone electrode with 2 mm of exposed tip was sequentially inserted into the dorsal root entry zone where 30-second, 80-degree lesions were made. The lesions were superficially continuous over the entire dorsal root entry zone from the upper cervical region to the obex. The postherpetic pain completely resolved immediately after surgery and the patient continued to have total pain relief 1 year later. An MRI performed 2 weeks after surgery clearly showed the location of the lesions. Conclusion: This unique clinical radiographic correlation shows that a nucleus caudalis dorsal root entry zone lesion, performed according to the described procedure, will be largely confined to the nucleus caudalis.
Repetitive Lumbar Punctures as Treatment for Normal Pressure Hydrocephalus
Authors: Lim T.S. , Yong S.W. , Moon S.Y.
Published: August 2009

Selected normal pressure hydrocephalus (NPH) patients cannot be treated by shunt operation because of the procedure’s high complication rate. We have treated cases in which prolonged clinical improvement of NPH was experienced after one or two lumbar punctures (LPs). We evaluated the predictors of prolonged improvement of NPH symptoms by repeated LP. Thirty-one NPH patients were retrospectively evaluated (age 72.5 ± 5.8 years). Gait disturbance, urinary incontinence, and cognitive impairment were semiquantified. We divided the patients into three groups (non-responders, temporary responders, and prolonged responders) according to their responses after LP. We analyzed the characteristics of the groups. Gait disturbance (p = 0.046) and urinary incontinence (p = 0.040) scores and total NPH symptom score (p = 0.007) after cerebrospinal fluid drainage were more significantly improved in prolonged responders than in temporary responders. On multiple logistic regression analyses, total NPH score improvement was the only predictor of the prolonged responders (p = 0.03, odds ratio 0.148). Our study showed that some NPH patients could maintain favorable courses for at least 1 year after LP without shunt operation. Repeated LP could be an alternative treatment in selected NPH patients.
Gait Variability among Healthy Adults: Low and High Stride-to-Stride Variability Are Both a Reflection of Gait Stability
Authors: Beauchet Olivier , Allali Gilles , Annweiler Cédric , Bridenbaugh Stephanie , Assal Frederic , Kressig Reto W. , Herrmann François R.
Published: August 2009

Background: It has been suggested that high stride-to-stride variability (STV) is a reflection of gait instability. However, both low and high STV has been shown in fallers and in nonfallers; therefore, the interpretation of STV of spatiotemporal gait parameters remains difficult. Thus, we sought to characterize and compare STV of spatial and temporal stride parameters among young and older healthy adults, and to determine the extent to which opposite results in STV could provide similar implications in terms of gait stability. Methods: Mean values of coefficients of variation of spatiotemporal gait parameters were collected from 30 young adults (14 men and 16 women; mean age 28.1 ± 6.0 years) and 33 older adults (2 men and 31 women; mean age 74.4 ± 7.1 years) walking at self-chosen normal walking speed over a GAITRite® System. Results: An age-related increase in STV was only observed with stride width (p = 0.012), whereas increased stride length and stance time variability in older adults were related to decreased walking speed (p = 0.006 and p = 0.018). In addition, both low and high STV was found in both groups of subjects and the highest value was observed for stride width (p < 0.001). Conclusion: The two main implications of the present results are that decreased walking speed should be taken into account when exploring age-related effects on gait variability, and that both low and high spatiotemporal STV may reflect gait stability in healthy adults.
Phosphorylation of Caveolin-1 Regulates Oxidant–Induced Pulmonary Vascular Permeability via Paracellular and Transcellular Pathways
Authors: Sun Yu , Hu Guochang , Zhang Xiumei , Minshall Richard D.
Published: August 2009

Rationale:

Oxidants are important signaling molecules known to increase endothelial permeability, although the mechanisms underlying permeability regulation are not clear.

Objective:

To define the role of caveolin-1 in the mechanism of oxidant-induced pulmonary vascular hyperpermeability and edema formation.

Methods and Results:

Using genetic approaches, we show that phosphorylation of caveolin-1 Tyr14 is required for increased pulmonary microvessel permeability induced by hydrogen peroxide (H
2
O
2
). Caveolin-1–deficient mice (
cav-1
−/−
) were resistant to H
2
O
2
-induced pulmonary vascular albumin hyperpermeability and edema formation. Furthermore, the vascular hyperpermeability response to H
2
O
2
was completely rescued by expression of caveolin-1 in
cav-1
−/−
mouse lung microvessels but was not restored by the phosphorylation-defective caveolin-1 mutant. The increase in caveolin-1 phosphorylation induced by H
2
O
2
was dose-dependently coupled to both increased
125
I-albumin transcytosis and decreased transendothelial electric resistance in pulmonary endothelial cells. Phosphorylation of caveolin-1 following H
2
O
2
exposure resulted in the dissociation of vascular endothelial cadherin/β-catenin complexes and resultant endothelial barrier disruption.

Conclusions:

Caveolin-1 phosphorylation–dependent signaling plays a crucial role in oxidative stress-induced pulmonary vascular hyperpermeability via transcellular and paracellular pathways. Thus, caveolin-1 phosphorylation may be an important therapeutic target for limiting oxidant-mediated vascular hyperpermeability, protein-rich edema formation, and acute lung injury.
A Longitudinal View of Apathy and Its Impact After Stroke
Authors: Mayo Nancy E. , Fellows Lesley K. , Scott Susan C. , Cameron Jill , Wood-Dauphinee Sharon
Published: August 2009

Background and Purpose—

Stroke survivors are often described as apathetic. Because apathy may be a barrier to participation in promising therapies, more needs to be learned about apathy symptoms after stroke. The specific objective was to estimate the extent to which apathy changes with time over the first year after stroke and the impact of apathy on recovery.

Methods—

The Apathy Assessed cohort was formed from stroke survivors participating in a longitudinal study of health-related quality of life after stroke. A family caregiver completed an apathy questionnaire by telephone at 1, 3, 6, and 12 months after stroke (n=408). Group-based trajectory modeling and ordinal regression were used to identify distinctive groups of individuals with similar trajectories of apathy over the first year after stroke and predictors of apathy trajectory.

Results—

Both 3- and 5-group trajectory models fit the data. We used the 5-group model because of the potential to further explore the apathy construct. The largest group (50%) had low apathy and 33% had minor apathy that remained stable throughout the first year after stroke. A small proportion (3%) of the study sample had high apathy that remained high. Two other groups of almost equal size (7%) showed worsening and improving apathy. Poor cognitive status, low functional status, and high comorbidity predicted higher apathy. High apathy had a significant negative effect on physical function, participation, health perception, and physical health over the first 12 months after stroke.

Conclusion—

Some degree of apathy was prevalent and persistent after stroke and was predicted by older age, poor cognitive status, and low functional status after stroke. Even a minor level of apathy had an important and statistically significant impact on stroke outcomes.
The History of "Religious" Consciousness and the Diffusion of Culture: Strategies for Surviving Dissolution
Authors: Lease Gary
Published: August 2009

In this essay, Gary Leason advances a sweeping theory of religion as a specific technology of power which dissolves its own conditions of possibility. Religion, simply put, is its own gravedigger because the strategies employed to impose patterns of consistency and control on the messy reality of contradiction and contingency must eventually succumb to unmanageable paradoxes.
Fluctuation of Mass Flux in a Cloud-Resolving Simulation with Interactive Radiation
Authors: Davoudi J. , McFarlane N. A. , Birner T.
Published: August 2009

It was shown by Craig and Cohen that fluctuations of cumulus clouds under homogeneous large-scale forcing satisfy the Gibbs canonical ensemble in a strict radiative–convective equilibrium (RCE). In the limit of random noninteracting convective cells, an analytical expression for the distribution function of total mass flux over a region of given size was derived.

The authors examine the consistency of the Gibbs canonical ensemble as a representation for the mass flux fluctuations when the large-scale forcing is time dependent. A cloud-resolving simulation (CRM) with interactive radiation, fixed imposed surface temperature, and diurnally varying solar forcing to mimic the diurnal cycle over the tropical ocean is used.

As a necessary condition for the existence of a state of quasi-equilibrium, the time-scale separation between convective processes and forcing is studied. Detailed evaluation of time scales of convective adjustment and memory in a three-month run confirms the hypothesis of time-scale separation.

The Craig and Cohen theory, in a varying range of heights between the cloud base up to the level of neutral buoyancy (LNB), is tested. It is shown that, although the theory is capable of reproducing the qualitative features of the variability, systematic deviations are detected. By quantifying the spatial distribution of the clouds, the authors suggest that deviations are associated with clustering effects.