julilili42/papers huggingface dataset:
“Sleep High - Train Low” Exerts Adaptative Effects On Ventilatory Response To Moderate Endurance Exercise
2005-05-01

PURPOSE This study determined whether repeated exposure to hypoxia in terms of sleep high - train low (SH) leads to adaptive changes in aerobic capacity, aerobic performance and the ventilatory response to exercise. METHODS Six non-altitude acclimated runners (H) spent 20 consecutive nights (10h/night) in normobaric hypoxia (FiO2 13.8%, corresponding to an altitude of 3300 above SL), whilst 6 control athletes (C) with similar training regimens slept under normoxic conditions. Before and after SH, a ramp test and an incremental exercise test on the treadmill were performed to determine maximum oxygen consumption (VO2max), maximum ventilation (VEmax) and running velocity at the individual anaerobic threshold (IAT), respectively. Before and after SH, the subjects additionally participated in a 15 min treadmill run (constant running velocity 75% IAT) in normoxia (CR-N), which was followed by an identical run in acute hypoxia (CR-H, FiO2 15.3%). RESULTS In H, oxygen saturation averaged 89.2 ± 2.4% at night. VO2max (before 66.6 ± 4.7/after 63,6 ± 4.9 ml/min/kg), VEmax (158.0 ± 18.3/159.0 ± 24.0 l) and IAT (17.1 ± 1.0/17.0 ± 1.5 km/h) were not affected by SH. In contrast, ventilation during CR-N (72.6 ± 12.7/78.9 ± 12.8 l) and CR-H (83.7 ± 14.9/90.7 ± 15.1 l) was significantly (p<0.05) higher after SH. This finding was not apparent in C. During CR-H, adaptation of ventilation to SH was paralleled by higher partial oxygen pressures (52.0 ± 5.8/57.3 ± 3.1 mmHg) and lower blood lactate concentrations (1.92 ± 0.36/1.34 ± 0.37 mmol/l) with no concomitant changes in C. CONCLUSIONS Passive exposure to repeated hypoxia as performed in the present study does not augment aerobic capacity, aerobic performance or maximal ventilation in endurance-trained athletes. However, SH enhances ventilatory response to moderate endurance exercise in normoxia as well as in hypoxia. This adaptive effect of SH is paralleled by a lower degree of hypoxemia and lower lactate concentrations if endurance exercise is performed in hypoxia. Thus, SH may be advantageous in acclimation to moderate endurance exercise at altitude. Supported by the Institut für Sportwissenschaft, Bonn, Germany
Yang-Mills wave functional in Coulomb gauge
2005-05-02

We investigate the dependence of the Yang-Mills wave functional in Coulomb\\ngauge on the Faddeev-Popov determinant. We use a Gaussian wave functional\\nmultiplied by an arbitrary power of the Faddeev-Popov determinant. We show,\\nthat within the resummation of one-loop diagrams the stationary vacuum energy\\nis independent of the power of the Faddeev-Popov determinant and, furthermore,\\nthe wave functional becomes field-independent in the infrared, describing a\\nstochastic vacuum. Our investigations show, that the infrared limit is rather\\nrobust against details of the variational ans\\\\"atze for the Yang-Mills wave\\nfunctional. The infrared limit is exclusively determined by the divergence of\\nthe Faddeev-Popov determinant at the Gribov horizon.\\n
Protein Determination
2005-05-03

Abstract Protein determination aims at estimating the concentration of protein by comparing the unknown sample with a known standard. Sample preparation and choice of a suitable standard are the most important criteria for the accuracy of the results.
Disturbed overt but normal covert shifts of attention in adult cerebellar patients
2005-05-04

In an attempt to provide a common denominator for cognitive deficits observed in cerebellar patients, it has been suggested that they might be secondary to impaired control of attention, a 'dysmetria of attention', conceptually analogous to motor dysmetria. Albeit appealing and quite influential, the concept of attentional dysmetria as a consequence of cerebellar disease remains controversial. In an attempt to test this concept in a direct way, we compared the performance of patients with cerebellar disorders to that of normal controls on tasks requiring either overt or covert shifts of spatial attention. In the first experiment, visually guided saccades, i.e. overt shifts of spatial attention, were elicited. In the second experiment, covert shifts of attention were evoked by the need to discriminate the orientation of a Landolt C observed during controlled fixation and presented in the same locations as the saccade targets in the previous experiment. The allocation of attention was assessed by comparing acuity thresholds determined with and without spatial cueing. The patients exhibited dysmetric saccades as reflected by larger absolute position errors or a higher number of corrective saccades compared to controls. In contrast, the ability to shift attention covertly was unimpaired in the patients, as indicated by a robust improvement in visual acuity induced by spatial cueing which did not differ from the one observed in the controls and which was independent of the range of SOAs (stimulus onset asynchronies) tested. Finally, the individual amount of saccadic dysmetria did not correlate with the individual performance in the covert attentional paradigm. In summary, we conclude that the contributions of the cerebellum to attention are confined to overt manifestations based on goal-directed eye movements.
Long-term outcome of conservative treatment in patients with diverticulitis of the sigmoid colon
2005-05-06

Despite a high rate of recurrences after conservative treatment of acute diverticulitis, lethal complications are rare. Surgery should thus mainly be undertaken to achieve relief of symptoms rather than to prevent death from complications.
Prolonged lesional expression of RhoA and RhoB following spinal cord injury
2005-05-06

Inhibition of the small GTPase ras homology protein (Rho) or its downstream target, the Rho-associated kinase (ROCK), has been shown to promote axon regeneration and to improve functional recovery following spinal cord injury (SCI) in the adult rat. Here, we have analyzed the expression of RhoA and RhoB following spinal cord injury in order to assess whether Rho is a possible target for late pharmacological intervention. In control spinal cords, RhoA(+) cells were almost absent, whereas RhoB was localized to some ependymal cells, a few microglia, and some dissociated neurons. In injured spinal cords, RhoA(+) and RhoB(+)cells accumulated at perilesional areas and in the developing necrotic core early after injury at day 1. After reaching their maximum levels (RhoA at day 3; RhoB at day 1), RhoA(+) and RhoB(+) cell numbers remained significantly elevated until day 28. In areas remote from the lesion (> or =0.75 mm), a more discrete accumulation of RhoA(+) and RhoB(+) cells was observed, primarily in areas of ongoing Wallerian degeneration. RhoA and RhoB were predominantly expressed by polymorphonuclear granulocytes, ED1(+) microglia/macrophages, oligodendrocytes, some neurons, and swollen axons/neurites. Furthermore, expression was located to lesional, reactive astrocytes and fibroblastoid cells confined to areas of scar formation. Our experiments have determined that most RhoA(+) and RhoB(+) cells (>70%) are of mononuclear origin. The persistent presence of lesional RhoA(+) and RhoB(+) axon/neurite fibers over a period of 4 weeks after injury suggests that Rho inhibition is a putative therapeutic concept also for delayed intervention after SCI.
Human immunosenescence: is it infectious?
2005-05-09

Summary: Morbidity and mortality due to infectious disease is greater in the elderly than in the young, at least partly because of age‐associated decreased immune competence, which renders individuals more susceptible to pathogens. This susceptibility is particularly evident for novel infectious agents such as in severe acute respiratory syndrome but is also all too apparent for common pathogens such as influenza. Many years ago, it was noted that the elderly possessed oligoclonal expansions of T cells, especially of CD8 + cells. At the same time, it was established that cytomegalovirus (CMV) seropositivity was associated with many of the same phenotypic and functional alterations to T‐cell immunity that were being reported as biomarkers associated with aging. It was discovered that CMV was the prime driving force behind most of the oligoclonal expansions and altered phenotypes and functions of CD8 cells. Independently, longitudinal studies of a free‐living population of the very old in Sweden over the past decade have led to the emerging concept of an ‘immune risk phenotype’ (IRP), predicting mortality, which was itself found to be associated with CMV seropositivity. These findings support our hypothesis that the manner in which CMV and the host immune system interact is critical in determining the IRP and hence is predictive of mortality. In this sense, then, we suggest that immunosenescence is contagious.
Organic Molecular Beam Deposition: Growth Studies beyond the First Monolayer
2005-05-09

This chapter contains sections titled: Introduction Organic molecular beam deposition General concepts of thin film growth Issues specific to organic thin film growth Overview of popular OMBD systems Films on oxidized silicon PTCDA DIP Phthalocyanines Pentacene Films on aluminium oxide PTCDA DIP Phthalocyanines Pentacene Films on metals PTCDA Structure and epitaxy of PTCDA/Ag(111) Comparison with other substrates Dewetting and thermal properties Real-time growth DIP Phthalocyanines Pentacene Films on other substrates More complex heterostructures and technical interfaces Summary and Conclusions
First evidence supporting a potential role for the BMP/SMAD pathway in the progression of oestrogen receptor‐positive breast cancer
2005-05-12

Abstract Oestrogen receptor expression is generally a sign of better tumour differentiation and comparatively good clinical outcome in invasive breast cancer. However, oestrogen receptor‐positive, poorly differentiated carcinomas with a poor clinical outcome exist. The underlying genetic mechanisms and the genes involved remain obscure, even though chromosome 7p gains seem to be associated with these uncommon tumours. In this study, we compared two subsets of oestrogen receptor‐positive breast cancers, which differed in tumour grade, cytogenetic instability, and tumour proliferation, for their differential gene expression in order to identify proteins involved in the progression of oestrogen receptor‐positive breast cancers. We were able to show by means of subtractive suppression hybridization, real‐time reverse transcriptase PCR, and tissue microarray analysis that expression of the bone morphogenetic protein receptor IB (BMPR‐IB) is a major hallmark of the progression and dedifferentiation of breast cancer. Strong expression of BMPR‐IB was associated with high tumour grade, high tumour proliferation, cytogenetic instability, and a poor prognosis in oestrogen receptor‐positive carcinomas. Western blot analysis revealed that downstream signalling of this receptor is mainly mediated via phosphorylation of SMAD 1 in oestrogen receptor‐positive breast cancer. Even though BMPR‐IB was expressed in oestrogen receptor‐positive and ‐negative breast cancers, an impact on tumour grade, proliferation, and cytogenetic instability, as parameters of tumour progression, could only be demonstrated in oestrogen receptor‐positive carcinomas. This pro‐proliferative effect was complemented by significant anti‐apoptotic activity, indicated by XIAP and IAP‐2 expression in BMPR‐IB‐positive carcinomas. These results show that the BMP/SMAD pathway is activated in breast cancer and may contribute to breast cancer progression and dedifferentiation in oestrogen receptor‐positive breast cancer. The definition of this pathway characterizes a new potential target in the molecular treatment of invasive breast cancer. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley &amp; Sons, Ltd.
Unusual trafficking pattern of Bartonella henselae -containing vacuoles in macrophages and endothelial cells
2005-05-12

Bartonella henselae, the agent of cat-scratch disease and vasculoproliferative disorders in humans, is a fastidious facultative intracellular pathogen, whose interaction with macrophages and endothelial cells (ECs) is crucial in the pathogenesis of these diseases. However, little is known about the subcellular compartment in which B. henselae resides. Two hours after infection of murine macrophages and human ECs, the majority of B. henselae-containing vacuoles (BCVs) lack typical endocytic marker proteins, fail to acidify, and do not fuse with lysosomes, suggesting that B. henselae resides in a non-endocytic compartment. In contrast to human umbilical vein endothelial cells, bacterial death and lysosomal fusion with BCVs is apparent in J774A.1 macrophages at 24 h. This phenomenon of delayed lysosomal fusion requires bacterial viability, and is confined to the BCV itself. Using magnetic selection, we enriched for transposon-mutagenized B. henselae trapped in lysosomes of macrophages 2 h after infection. Genes affected appear to be relevant to the intracellular lifestyle in macrophages and ECs and include some previously implicated in Bartonella pathogenicity. We conclude that B. henselae has a specific capacity to actively avoid the host endocytic pathway after entry of macrophages and ECs, from within a specialized non-endocytic membrane-bound vacuole.
Scientific findings of Alexander von Humboldt's expedition into the Spanish-American Tropics (1799-1804) from a geographical point of view
2005-05-12

Alexander von Humboldt's expedition from 1799 till 1804 to the "equinoctial regions of the new world" led through Venezuela, Cuba, Colombia, Ecuador, Peru, and Mexico. In Europe an increased knowledge of the "New World" was connected with the privately funded journey, which served purely scientific purposes and had nothing to do with the exploration and exploitation of natural resources. Besides the research results, which were based on new measuring methods and the quantitative ascertainment of scientific basics, the journey also made possible detailed descriptions in matters of regional studies including social, socio-economic, political, and economic-geographic circumstances, which were based on empirical field studies. The expedition took place shortly before the political change in Latin America. Humboldt, who still experienced the feudal character of global economy based on slave labor in the colonies, vehemently criticized this economic structure - although he was a noble - and its unbearable social conditions. This is the reason why Humboldt is still admired in Latin America till this day. In Europe the scientific insights of his journey to the tropics and his innovative impulses in geog raphy as well as in many other disciplines brought him fame and lasting recognition as a universal scholar, who had crucial influence on the development of the sciences during the first half of the 19th century.
Autophagy promotes MHC class II presentation of peptides from intracellular source proteins
2005-05-13

MHC–peptide complexes mediate key functions in adaptive immunity. In a classical view, MHC-I molecules present peptides from intracellular source proteins, whereas MHC-II molecules present antigenic peptides from exogenous and membrane proteins. Nevertheless, substantial crosstalk between these two pathways has been observed. We investigated the influence of autophagy on the MHC-II ligandome and demonstrated that peptide presentation is altered considerably upon induction of autophagy. The presentation of peptides from intracellular and lysosomal source proteins was strongly increased on MHC-II in contrast with peptides from membrane and secreted proteins. In addition, autophagy influenced the MHC-II antigen-processing machinery. Our study illustrates a profound influence of autophagy on the class II peptide repertoire and suggests that this finding has implications for the regulation of CD4 + T cell-mediated processes.
Alpha‐synuclein and Parkinson's disease: Implications from the screening of more than 1,900 patients
2005-05-13

Abstract Data on the frequency of α‐ synuclein mutations in Parkinson's disease (PD) are limited. Screening the entire coding region in 1,921 PD patients with denaturing high performance liquid chromatography and subsequent sequencing we only detected silent mutations (g.2654A&gt;G, g.10151G&gt;A, and g.15986A&gt;T) and the c.209G&gt;A substitution corresponding to the p.A53T mutation. These results demonstrate that mutations in the α‐ synuclein gene are rare and suggest that other factors contribute to α‐ synuclein aggregation in the majority of PD patients. © 2005 Movement Disorder Society
Steroid Profile in an Adrenocortical Carcinoma Producing Aldosterone
2005-05-13

We report a rare case of primary aldosteronism due to an adrenocortical carcinoma. A 61-year-old woman with a history of hypertension and hypokalemia was referred for evaluation of a 4.2 cm measuring adrenal mass without secondary signs of malignancy. Endocrinological testing was consistent with primary aldosteronism. The patient underwent surgical resection of the adrenal mass; histology revealed an adrenocortical carcinoma. Postoperatively blood pressure, serum potassium, and aldosterone returned to normal. Four months after adrenalectomy, the patient presented again with hypokalemic hypertension and was found to have metastatic disease. Endocrinological investigation revealed primary aldosteronism and subclinical autonomous glucocorticoid hypersecretion. Careful hormonal investigation should be obtained in patients with adrenal masses causing excessive aldosterone secretion. In uncertain cases of primary aldosteronism, we would suggest to measure 18-hydroxycortisol levels, as excessive amounts may indicate adrenocortical carcinoma.
Visualizing structural properties of irregular parallel computations
2005-05-14

An important task in parallel programming is the appropriate distribution of work on the processors. This distribution is usually dynamically changing and hard to predict, further it is very sensitive to the change of parameters. Even with advanced analysis tools this problem is hard to be solved. We propose to visualize the program structure as it changes over the execution time. We therefore present a new automatic layout algorithm based on Sugiyama's framework, which enables the user to detect structural patterns which might be fatal for the performance of the program - patterns which might be impossible to detect in a more analytical way. Furthermore it assists the user to find appropriate timing parameters for load balancing. We integrate our visualization into an integrated development environment that supports the implementation, execution, and analysis of parallel programs.
Lack of Wall Teichoic Acids inStaphylococcus aureusLeads to Reduced Interactions with Endothelial Cells and to Attenuated Virulence in a Rabbit Model of Endocarditis
2005-05-15

Wall teichoic acids (WTAs) are major surface components of gram-positive bacteria that have recently been shown to play a key role in nasal colonization by Staphylococcus aureus. In the present study, we assessed the impact that WTAs have on endovascular infections by using a WTA-deficient S. aureus mutant ( Delta tagO). There were no significant differences detected between the isogenic parental strain (SA113) and the Delta tagO mutant in polymorphonuclear leukocyte-mediated opsonophagocytosis; killing by a prototypic platelet microbicidal protein; or binding to platelets, fibronectin, or fibrinogen. However, compared with the parental strain, the Delta tagO mutant adhered considerably less well to human endothelial cells, especially under flow conditions (70.3% reduction; P<.05). Beads coated with WTA bound to endothelium in a dose-dependent manner, suggesting that WTA contributes specifically to this interaction. These in vitro data closely paralleled those from a rabbit model of infective endocarditis in which the Delta tagO mutant was compared with the parental strain. Clearances of staphylococcus from the bloodstream were equivalent, but the Delta tagO mutant showed a significantly reduced capacity to both colonize sterile cardiac vegetations (P<.05) and proliferate within these vegetations, the kidneys, and the spleen (P<.001). We conclude that WTA is an important factor in the induction and progression of endovascular S. aureus infection, likely through a specific interaction with endothelial cells.
The Sickle Cell Trait Is Associated with Enhanced Immunoglobulin G Antibody Responses toPlasmodium falciparumVariant Surface Antigens
2005-05-15

The sickle cell trait (HbAS) protects against severe Plasmodium falciparum malaria in young African children. We investigated the extent of the association between HbAS and antibodies directed to parasite-derived variant surface antigens (VSAs) on the membrane of infected erythrocytes. We measured immunoglobulin G (IgG) responses with specificity for VSAs of 2 heterologous parasite isolates in 458 Gabonese children aged between 6 months and 11 years. Logistic regression analyses showed a highly significant independent association (P<.001) between carriage of HbAS and the presence of IgG anti-VSA responses; this association was related specifically to IgG1 and IgG4 subclasses in the anti-VSA profile. IgG2 and IgG3 anti-VSA responses were both independently associated with older age, consistent with the pattern observed in semi-immune adults. The results imply that enhanced levels of cross-reactive anti-VSA responses in children with HbAS may be intimately associated with the protection they have against malaria.
Activation Status of Cord Blood γδ T Cells Reflects In Utero Exposure toPlasmodiumfalciparumAntigen
2005-05-15

The findings imply that treatment of P. falciparum malaria during pregnancy leads to enhanced innate immune T cell activation and proinflammatory cytokine responses in both maternal and fetal compartments. Ongoing placental P. falciparum infection, conversely, is associated with an absence of such activity.