bluuebunny/crossref_metadata_2025 huggingface dataset:
Avian Influenza A Virus Polymerase Association with Nucleoprotein, but Not Polymerase Assembly, Is Impaired in Human Cells during the Course of Infection
Authors: Rameix-Welti Marie-Anne , Tomoiu Andru , Dos Santos Afonso Emmanuel , van der Werf Sylvie , Naffakh Nadia
Published: November 2008

Strong determinants of the host range of influenza A viruses have been identified on the polymerase complex formed by the PB1, PB2, and PA subunits and on the nucleoprotein (NP). In the present study, molecular mechanisms that may involve these four core proteins and contribute to the restriction of avian influenza virus multiplication in human cells have been investigated. The efficiencies with which the polymerase complexes of a human and an avian influenza virus isolate assemble and interact with the viral NP and cellular RNA polymerase II proteins were compared in mammalian and in avian infected cells. To this end, recombinant influenza viruses expressing either human or avian-derived core proteins with a PB2 protein fused to the One-Strep purification tag at the N or C terminus were generated. Copurification experiments performed on infected cell extracts indicate that the avian-derived polymerase is assembled and interacts physically with the cellular RNA polymerase II at least as efficiently as does the human-derived polymerase in human as well as in avian cells. Restricted growth of the avian isolate in human cells correlates with low levels of the core proteins in infected cell extracts and with poor association of the NP with the polymerase compared to what is observed for the human isolate. The NP-polymerase association is restored by a Glu-to-Lys substitution at residue 627 of PB2. Overall, our data point to viral and cellular factors regulating the NP-polymerase interaction as key determinants of influenza A virus host range. Recombinant viruses expressing a tagged polymerase should prove useful for further studies of the molecular interactions between viral polymerase and host factors during the infection cycle.
Infection with Human Metapneumovirus Predisposes Mice to Severe Pneumococcal Pneumonia
Authors: Kukavica-Ibrulj Irena , Hamelin Marie-Ève , Prince Gregory A. , Gagnon Constance , Bergeron Yves , Bergeron Michel G. , Boivin Guy
Published: November 2008

Human metapneumovirus (hMPV) is a recently described paramyxovirus that causes respiratory tract infections. Prior clinical studies have highlighted the importance of respiratory viruses, such as influenza virus, in facilitating secondary bacterial infections and increasing host immunopathology. The objective of the present work was to evaluate the effects of initial viral infection with hMPV or influenza A virus followed byStreptococcus pneumoniaesuperinfection 5 days later in a murine model. Both groups of superinfected mice demonstrated significant weight loss (mean of 15%) and higher levels of airway obstruction (mean enhanced pause value of 2.7) compared to those of mice infected with hMPV, influenza virus, or pneumococcus alone. Bacterial counts increased from 5 × 102CFU/lung in mice infected with pneumococcus only to 107and 109CFU/lung in mice with prior infections with hMPV and influenza A virus, respectively. A more pronounced interstitial and alveolar inflammation correlated with higher levels of inflammatory cytokines and chemokines such as interleukin-1α (IL-1α), IL-1β, IL-6, IL-12, monocyte chemotactic protein 1, macrophage inflammatory protein 1α, KC, and granulocyte colony-stimulating factor, as well as greater expression of Toll-like receptor 2 (TLR2), TLR6, TLR7, and TLR13 in the lungs of superinfected animals compared to results for single infections, with similar immunological effects seen in both coinfection models. Prior infection with either hMPV or influenza A virus predisposes mice to severe pneumococcus infection.
RNA Silencing against Geminivirus: Complementary Action of Posttranscriptional Gene Silencing and Transcriptional Gene Silencing in Host Recovery
Authors: Rodríguez-Negrete Edgar A. , Carrillo-Tripp Jimena , Rivera-Bustamante Rafael F.
Published: November 2008

RNA silencing in plants is a natural defense system mechanism against invading nucleic acids such as viruses. Geminiviruses, a family of plant viruses characterized by a circular, single-stranded DNA genome, are thought to be both inducers and targets of RNA silencing. Some natural geminivirus-host interactions lead to symptom remission or host recovery, a process commonly associated with RNA silencing-mediated defense.
Pepper golden mosaic virus
(PepGMV)-infected pepper plants show a recovery phenotype, which has been associated with the presence of virus-derived small RNAs. The results presented here suggest that PepGMV is targeted by both posttranscriptional and transcriptional gene silencing mechanisms. Two types of virus-related small interfering RNAs (siRNAs) were detected: siRNAs of 21 to 22 nucleotides (nt) in size that are related to the coding regions (Rep, TrAP, REn, and movement protein genes) and a 24-nt population primarily associated to the intergenic regions. Methylation levels of the PepGMV A intergenic and coat protein (CP) coding region were measured by a bisulfite sequencing approach. An inverse correlation was observed between the methylation status of the intergenic region and the concentration of viral DNA and symptom severity. The intergenic region also showed a methylation profile conserved in all times analyzed. The CP region, on the other hand, did not show a defined profile, and its methylation density was significantly lower than the one found on the intergenic region. The participation of both PTGS and TGS mechanisms in host recovery is discussed.
Baculovirus Data Suggest a Common but Multifaceted Pathway for Sorting Proteins to the Inner Nuclear Membrane
Authors: Braunagel Sharon C. , Cox Virginia , Summers Max D.
Published: November 2008

Multiple unique protein markers sorted to the inner nuclear membrane (INM) from the
Autographa californica
nucleopolyhedrovirus occlusion-derived virus (ODV) envelope were used to decipher common elements of the sorting pathway of integral membrane proteins from their site of insertion into the membrane of the endoplasmic reticulum (ER) through their transit to the INM. The data show that during viral infection, the viral protein FP25K is a partner for all known ODV envelope proteins and that BV/ODV-E26 (designated E26) is a partner for some, but not all, such proteins. The association with the ER membrane of FP25K, E26, and the cellular INM-sorting protein importin-α-16 is not static; rather, these sorting proteins are actively recruited to the ER membrane based upon requirements of the proteins in transit to the INM. Colocalization analysis using an ODV envelope protein and importin-α-16 shows that during viral infection, importin-α-16 translocates across the pore membrane to the INM and then is incorporated into the virus-induced intranuclear membranes. Thus, the association of importin-α-16 and INM-directed proteins appears to remain at least through protein translocation across the pore membrane to the INM. Overall, the data suggest that multiple levels of regulation facilitate INM-directed protein trafficking, and that proteins participating in this sorting pathway have a dynamic relationship with each other and the membrane of the ER.
The groin triangle: a patho-anatomical approach to the diagnosis of chronic groin pain in athletes
Authors: Falvey E C , Franklyn-Miller A , McCrory P R
Published: November 2008

Chronic groin pain is a common presentation in sports medicine. It is most often a problem in those sports that involve kicking and twisting movements while running. The morbidity of groin pain should not be underestimated, ranking behind only fracture and anterior cruciate ligament reconstruction in terms of time out of training and play. Due to the insidious onset and course of pathology in the groin region it commonly presents with well-established pathology. Without a clear clinical/pathological diagnosis, the subsequent management of chronic groin pain is difficult. The combination of complex anatomy, variability of presentation and the non-specific nature of the signs and symptoms make the diagnostic process problematical. This paper proposes a novel educational model based on patho-anatomical concepts. Anatomical reference points were selected to form a triangle, which provides the discriminative power to restrict the differential diagnosis and form the basis of ensuing investigation. This paper forms part of a series addressing the three-dimensional nature of proximal lower limb pathology. The 3G approach (groin, gluteal and greater trochanter triangles) acknowledges this, permitting the clinician to move throughout the region, considering pathologies appropriately.
A prospective longitudinal study to assess psychological changes following anterior cruciate ligament reconstruction surgery
Authors: Langford J L , Webster K E , Feller J A
Published: November 2008

Objective:

To determine whether the psychological characteristics of athletes who have undergone an anterior cruciate ligament (ACL) reconstruction change during rehabilitation are related to returning to competitive sport.

Design:

Prospective longitudinal study.

Method:

87 athletes completed the Emotional Response of Athletes to Injury Questionnaire (ERAIQ) and the ACL Return to Sport after Injury scale (ACL-RSI) at 3, 6 and 12 months following ACL reconstruction surgery. Physical outcome measures were also taken at each time point.

Results:

At 12 months 44 (51%) participants had returned to competitive sport and 43 (49%) participants had not returned. There were no differences in physical recovery or scores on the ERAIQ between the two groups. Participants who had returned to competitive sport at 12 months, however, scored significantly higher on the ACL-RSI scale (reflecting a more positive psychological response about sport participation) at both 6 and 12 months than participants who had not returned to competitive sport.

Conclusions:

During rehabilitation there are significant psychological differences regarding sport resumption between athletes who do, and do not, resume competitive sport 12 months following ACL reconstruction. These differences occur as early as 6 months postoperatively and highlight the importance of addressing all aspects of an athlete’s recovery in order to help facilitate the athlete returning to sport.
Nutrient Availability for Phytoplankton Production in a Multiple-Impoundment Series
Authors: Elser James J. , Kimmel Bruce L.
Published: November 2008

We investigated the availability of nitrogen (N) and phosphorus (P) for phytoplankton production and the importance of inter-reservoir nutrient transfers in a headwater-to-mainstream series of three hypolimnetic-discharge impoundments during June–December 1982. Dissolved nutrient analyses and enrichment experiments indicated that P, rather than N, was the primary limiting nutrient for plankton growth throughout the reservoir series. Phytoplankton P deficiency, as reflected by chlorophyll-specific alkaline phosphatase activity (APA), peaked in late August, and then decreased during the fall and winter. Late in the growing season, APA levels increased downstream within each reservoir, reflecting uplake-to-downlake decreases in P availability, but decreased downstream from reservoir to reservoir, indicating increased P availability down the impoundment series. In this reservoir series, hypolimnetic releases of water and nutrients from upstream impoundments during the growing season appear to enhance nutrient availability for phytoplankton production in impoundments downstream. This result suggests that the productivity of reservoirs located in multiple-impoundment series should be viewed in the context of the limnological dynamics resulting from river basin-level reservoir operations.
A Stochastic Population Model for Managing the Atlantic Menhaden (Brevoortia tyrannus) Fishery and Assessing Managerial Risks
Authors: Ruppert D. , Reish R. L , Deriso R. B. , Carroll R. J.
Published: November 2008

A model including an age-structure, a stochastic egg-recruitment relationship, density-dependent juvenile growth, age-dependent fishing mortality, and fecundity dependent upon size as well as age was used to investigate three types of harvesting strategies: constant yearly catch policies, constant fishing mortality rate policies, and "egg escapement" policies, which are defined in the article. Because of stochastic recruitment, constant yearly catch policies appear unsuitable for managing Atlantic menhaden (Brevoortia tyrannus). Both other types of policies are suitable, but the egg escapement policies have higher long-term average catches. Using decision theory, we investigated risks due to the randomness of recruitment and to the estimation errors for the biographical parameters in our model. The risks appear to be acceptable.
Organization of Microsatellites Differs between Mammals and Cold-water Teleost Fishes
Authors: Brooker Amanda L. , Cook Doug , Bentzen Paul , Wright Jonathan M. , Doyle Roger W.
Published: November 2008

Microsatellites, in particular (dG-dT)nand (dG-dA)ndinucleotide repeats, are abundant and display a high degree of length polymorphism and heterozygosity in eukaryotic genomes. Here, we report the cloning and characterization of 64 microsatellite sequences from Atlantic cod, Gadus morhua. The microsatellites were classified as perfect, imperfect, and compound repeats. The length and integrity of these repeats were compared with microsatellites characterized from two other teleosts, rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar), and from three mammalian genomes, human, porcine, and canine. Differences were found in the proportions of the repeat classes; however, the most significant difference between microsatellites from teleost fishes and mammals was the propensity of the former to be of greater length: some cod and rainbow trout microsatellites were more than twice the size of the longest microsatellite repeats reported for any mammalian genome. Primers for PCR amplification were constructed for seven of the cod microsatellites. Allele frequencies, degree of polymorphism, and heterozygosity were estimated for a sample population. Amplification with these cod primers was also carried out on a number of related gadids. These polymorphic microsatellite loci have enormous potential utility as genetic markers for use in population, breeding, and evolutionary studies.
An Inverse Model Analysis of Planktonic Food Webs in Experimental Lakes
Authors: Vézina Alain F. , Pace Michael L.
Published: November 2008

We used inverse methods to reconstruct carbon flows in experimental lakes where the fish community had been purposely altered. These analyses were applied to three years of data from a reference lake and two experimental lakes located in Gogebic County, Michigan. We reconstructed seasonally averaged flows among two size groups of phytoplankton, heterotrophic bacteria, microzooplankton, cladocerans, and copepods. The inverse analysis produced significantly different flow networks for the different lakes that agreed qualitatively with known chemical and biological differences between lakes and with other analyses of the impact of fish manipulations on food web structure and dynamics. The results pointed to alterations in grazing pressure on the phytoplankton that parallel changes in the size and abundance of cladocerans and copepods among lakes. Estimated flows through the microbial food web indicated low bacterial production efficiencies and small carbon transfers from the microbial food web to the larger zooplankton. This study demonstrates the use of inverse methods to identify and compare flow patterns across ecosystems and suggests that microbial flows are relatively insensitive to changes at the upper trophic levels.
Maturation of White Sucker,Catostomus commersoni, Populations in Ontario
Authors: Chen Y. , Harvey H. H.
Published: November 2008

White sucker, Catostomus commersoni, were sampled from 13 Ontario lakes. Two growth parameters (growth rate in length as dL/dt at age t0and age at maximum growth rate in weight as dW/dt) were estimated by fitting length- and weight-at-age data to the two reparameterized von Bertalanffy growth functions for each of 13 populations. Two maturation parameters (length and age at 50% maturity, ML and MA) were estimated using the linear regression method for both sexes. Two regression approaches were used in analyzing experimental data: a traditional geometric means (GM) method and a two-step procedure of robust regression analysis which includes applying the least median squares method to identify possible outliers and applying the GM method to data exclusive of the defined outliers. Great among-population variation in the estimated growth and maturation parameters was observed for both female and male white sucker. White sucker growing faster at young ages tended to mature earlier. High population density might result in white sucker having slower growth rates in their earlier ages and larger MA's. This study indicated that maturation of white sucker is food dependent, and early growth rate is an important factor in determining the timing of maturity.
ORDERED AND $\mathcal{J}$-TRIVIAL SEMIGROUPS AS DIVISORS OF SEMIGROUPS OF LANGUAGES
Authors: VERNITSKI ALEXEI
Published: November 2008

A semigroup of languages is a set of languages considered with (and closed under) the operation of catenation. In other words, semigroups of languages are subsemigroups of power-semigroups of free semigroups. We prove that a (finite) semigroup is positively ordered if and only if it is a homomorphic image, under an order-preserving homomorphism, of a (finite) semigroup of languages. Hence it follows that a finite semigroup is [Formula: see text]-trivial if and only if it is a homomorphic image of a finite semigroup of languages.
THE EFFICIENCY OF GRAVITATIONAL BREMSSTRAHLUNG PRODUCTION IN THE COLLISION OF TWO SCHWARZSCHILD BLACK HOLES
Authors: ARANHA R. F. , DE OLIVEIRA H. P. , DAMIÃO SOARES I. , TONINI E. V.
Published: November 2008

In this paper, we examine the efficiency of gravitational bremsstrahlung production in the process of head-on collision of two boosted Schwarzschild black holes. We construct initial data for the characteristic initial value problem in Robinson–Trautman space–times, which represent two instantaneously stationary Schwarzschild black holes in motion toward each other with the same velocity. The Robinson–Trautman equation is integrated for these initial data using a numerical code based on the Galerkin method. The resulting final configuration is a boosted black hole with Bondi mass greater than the sum of the individual masses of the individual initial black holes. Two relevant aspects of the process are presented. The first relates the efficiency Δ of the energy extraction by gravitational wave emission to the mass of the final black hole. This relation is fitted by a distribution function of nonextensive thermostatistics with entropic parameter q ≃ 1/2; the result extends and validates analysis based on the linearized theory of gravitational wave emission. The second aspect is a typical bremsstrahlung angular pattern in the early period of emission at the wave zone, a consequence of the deceleration of the black holes as they coalesce; this pattern evolves to a quadrupole form for later times.
DECAY OF MASSIVE DIRAC HAIRS ON BRANE-WORLD BLACK HOLES
Authors: JING JILIANG , PAN QIYUAN , DING CHIKUN
Published: November 2008

The late-time evolution of massive Dirac fields in the backgrounds of brane-world black holes is investigated. We find that the dumping exponent depends on both the multiple number of the wave mode and the mass of the Dirac fields, but almost does not depend on the parameter ϒ of the brane-world black holes. We also find that the decay rate of the asymptotic late-time tail is t-5/6. Our results show that the decay of massive Dirac hairs on brane-world black holes has the same behavior as that of the Schwarzschild black hole.
A NOVEL ALGORITHM FOR SPEEDING UP KEYPOINT DETECTION AND MATCHING
Authors: LI JING , YANG TAO , PAN QUAN , CHENG YONG-MEI , HOU JUN
Published: November 2008

This work proposes a novel keypoint detector called QSIF (Quality and Spatial based Invariant Feature Detector). The primary contributions include: (1) a multilevel box filter is used to build the image scales efficiently and precisely, (2) by examining pixels in quality and spatial space simultaneously, QSIF can directly locate the keypoints without scale space extrema detection in the entire image spatial space, (3) QSIF can precisely control the number of output keypoints while maintaining almost the same repeatability of keypoint detection. This characteristic is essential in many real-time application fields. Extensive experimental results with images under scale, rotation, viewpoint and illumination changes demonstrate that the proposed QSIF has a stable and satisfied repeatability, and it can greatly speed up the keypoint detect and matching.
IN VIVO MAPPING BRAIN MICROCIRCULATION BY LASER SPECKLE CONTRAST IMAGING: A MAGNETIC RESONANCE PERSPECTIVE OF THEORETICAL FRAMEWORK
Authors: WANG ZHENG
Published: November 2008

The fundamental limitations of most vascular-based functional neuroimaging techniques are placed by the fact how fine the brain regulates the blood supply system. In vivo mapping of the cerebral microcirculation with high resolution and sensitivity hence becomes unprecedentedly compelling. This paper reviews the theoretical background of the laser speckle contrast imaging (LSCI) technique and attempts to present a complete framework stemming from a simple biophysical model. Through the sensitivity analysis, more insights into the tool optimization are attained for in vivo applications. Open questions of the technical aspects are discussed within this unified framework. Finally, it concludes with a brief perspective of future research in a way analogous to the magnetic resonance imaging (MRI) technique. Such exploration could catalyze their development and initiate a technological fusion for precise assessment of blood flow across various spatial scales.
ATP and adenosine in the local regulation of water transport and homeostasis by the kidney
Authors: Rieg Timo , Vallon Volker
Published: November 2008

Regulation of body water homeostasis is critically dependent on the kidney and under the control of AVP, which is released from the neurohypophysis. In the collecting duct (CD) of the kidney, AVP activates adenylyl cyclase via vasopressin V2receptors. cAMP-dependent activation of protein kinase A phosphorylates the water channel aquaporin-2 and increases water permeability by insertion of aquaporin-2 into the apical cell membrane. However, local factors modulate the effects of AVP to fine tune its effects, accelerate responses, and potentially protect the integrity of CD cells. Nucleotides like ATP belong to these local factors and act in an autocrine and paracrine way to activate P2Y2receptors on CD cells. Extracellular breakdown of ATP and cAMP forms adenosine, the latter also induces specific effects on the CD by activation of adenosine A1receptors. Activation of both receptor types can inhibit the cAMP-triggered activation of protein kinase A and reduce water permeability and transport. This review focuses on the role and potential interactions of the ATP and adenosine system with regard to the regulation of water transport in the CD. We address the potential stimuli and mechanisms involved in nucleotide release and adenosine formation, and discuss the corresponding signaling cascades that are activated. Potential interactions between the ATP and adenosine system, as well as other factors involved in the regulation of CD function, are outlined. Data from pharmacological studies and gene-targeted mouse models are presented to demonstrate the in vivo relevance to water transport and homeostasis.
Urinary fatty acid-binding protein 1: an early predictive biomarker of kidney injury
Authors: Noiri Eisei , Doi Kent , Negishi Kousuke , Tanaka Tamami , Hamasaki Yoshifumi , Fujita Toshiro , Portilla Didier , Sugaya Takeshi
Published: November 2008

In the development of novel therapeutic strategies for kidney disease, new renal biomarkers for early detection and accurate evaluation of renal injury are urgently required for both acute kidney injury (AKI) and chronic kidney disease (CKD). Fatty acid-binding protein 1 (FABP1) is expressed in renal proximal tubule cells and shed into urine in response to hypoxia caused by decreased peritubular capillary blood flow. To clarify the role of urinary FABP1 in kidney disease, we established human FABP1 transgenic mice and evaluated the responses of FABP1 to several AKI and CKD models. Moreover, there are accumulating clinical data that urinary FABP1 can detect human AKI earlier than serum creatinine and can distinguish the risk population for AKI. Investigation with “humanized” FABP1 transgenic mice and measurement of clinical samples allowed us to develop urinary FABP1 as a new renal biomarker. Further clinical studies are necessary to confirm the potential of urinary FABP1 for clinical application.
The difference in ventilation heterogeneity between asthmatic and healthy subjects quantified using hyperpolarized 3He MRI
Authors: Tzeng Yang-Sheng , Lutchen Kenneth , Albert Mitchell
Published: November 2008

In this pilot study, algorithms for quantitatively evaluating the distribution and heterogeneity of human ventilation imaged with hyperpolarized (HP) 3He MRI were developed for the goal of examining structure-function relationships within the asthmatic lung. Ten asthmatic and six healthy human subjects were imaged with HP 3He MRI before bronchial challenge (pre-MCh), after bronchial challenge (post-MCh), and after a series of deep inspirations (post-DI) following challenge. The acquired images were rigidly coregistered. Local voxel fractional ventilation was computed by setting the sum of the pixel intensity within the lung region in each image to 1 liter of inhaled 3He mixture. Local ventilation heterogeneity was quantified by computing regional signal coefficient of variation. Voxel fractional ventilation histograms and overall heterogeneity scores were then calculated. Asthmatic subjects had a higher ventilation heterogeneity to begin with ( P = 0.025). A methacholine challenge elevated ventilation heterogeneity for all subjects (difference: P = 0.08). After a DI postchallenge, this heterogeneity reversed substantially toward the baseline state for healthy subjects but only minimally in asthmatic subjects. This difference was significant in absolute quantity (difference: P = 0.007) as well as relative to the initial increase (difference: P = 0.03). These findings suggest that constriction heterogeneity is not a characteristic unique to asthmatic airway trees but rather a behavior intrinsic to all airway trees when provoked. Once ventilation heterogeneity is established, it is the lack of reversal following DIs that distinguishes asthmatics from non-asthmatics.
Thermal manipulations in late-term chick embryos have immediate and longer term effects on myoblast proliferation and skeletal muscle hypertrophy
Authors: Piestun Yogev , Harel Michal , Barak Miriam , Yahav Shlomo , Halevy Orna
Published: November 2008

We investigated the cellular and molecular bases for the promotion of muscle development and growth by temperature manipulations (TMs) during late-term chick embryogenesis. We show that incubation at 39.5°C (increase of 1.7°C from normal conditions) from embryonic days 16 to 18 (E16 to E18) for 3 or 6 h daily increased diameter of myofibers as of day 13 of age and enhanced absolute muscle growth relative to controls, until day 35 of age. TMs had immediate (E17) and later (up to 2 wk posthatch) effects in elevating muscle cell proliferation relative to controls. This was indicated by higher DNA incorporation of thymidine and a higher number of cells expressing PCNA in intact muscle, accompanied by higher Pax7 levels, all reflecting a higher number of myogenic cells, and suggesting that the increased hypertrophy can be attributed to a higher reservoir of myogenic progeny cells produced in response to the TM. IGF-I levels were higher in the TM groups than in controls, implying a mechanism by which heat manipulations in chicks affect muscle development, with locally secreted IGF-I playing a major role. Whereas hypertrophy was similar in both TM groups, cell proliferation and Pax7 levels were more robust in the 6-h muscle, mainly posthatch, suggesting a differential effect of various TM periods on cell reservoir vs. hypertrophy and a high sensitivity of myoblasts to relatively small changes in heat duration with respect to these processes, which is manifested in the short and long term.
Force Regulation of Ankle Extensor Muscle Activity in Freely Walking Cats
Authors: Donelan J. M. , McVea D. A. , Pearson K. G.
Published: November 2008

To gain insight into the relative importance of force feedback to ongoing ankle extensor activity during walking in the conscious cat, we isolated the medial gastrocnemius muscle (MG) by denervating the other ankle extensors and measured the magnitude of its activity at different muscle lengths, velocities, and forces accomplished by having the animals walk up and down a sloped pegway. Mathematical models of proprioceptor dynamics predicted afferent activity and revealed that the changes in muscle activity under our experimental conditions were strongly correlated with Ib activity and not consistently associated with changes in Ia or group II activity. This allowed us to determine the gains within the force feedback pathway using a simple model of the neuromuscular system and the measured relationship between MG activity and force. Loop gain increased with muscle length due to the intrinsic force–length property of muscle. The gain of the pathway that converts muscle force to motoneuron depolarization was independent of length. To better test for a causal relationship between modulation of force feedback and changes in muscle activity, a second set of experiments was performed in which the MG muscle was perturbed during ground contact of the hind foot by dropping or lifting the peg underfoot. Collectively, these investigations support a causal role for force feedback and indicate that about 30% of the total muscle activity is due to force feedback during level walking. Force feedback's role increases during upslope walking and decreases during downslope walking, providing a simple mechanism for compensating for changes in terrain.
Ischemic Postconditioning in Pigs
Authors: Skyschally Andreas , van Caster Patrick , Boengler Kerstin , Gres Petra , Musiolik Judith , Schilawa Dustin , Schulz Rainer , Heusch Gerd
Published: November 2008

Ischemic postconditioning (IPoC) reduces infarct size following ischemia/reperfusion. Whether or not phosphorylation of RISK (reperfusion injury salvage kinases) (AKT, ERK1/2, P70S6K, GSK3β) is causal for protection by IPoC is controversial. We therefore studied the impact of RISK on IPoC in anesthetized pigs subjected to 90 minutes of left anterior descending coronary artery hypoperfusion and 120 minutes of reperfusion. In protocol 1, IPoC, by 6 cycles of 20/20 seconds of reperfusion/reocclusion (n=13), was compared with immediate full reperfusion (IFR) (n=15). In protocol 2, IPoC (n=4) or IFR (n=4) was performed with pharmacological RISK blockade by IC coinfusion of Wortmannin and U0126. Infarct size was determined by TTC staining, and the expression of phosphorylated RISK proteins by Western blot analysis in biopsies. In protocol 1, infarct size was 20±3% (percentage of area at risk; mean±SEM) with IPoC and 33±4% (
P
<0.05) with IFR. RISK phosphorylation increased with reperfusion but was not different between IPoC and IFR. In protocol 2, Wortmannin and U0126 blocked the increases in RISK phosphorylation during reperfusion, but infarct size was still smaller with IPoC (15±7%) than with IFR (35±6%;
P
<0.05).
Paradoxes of Collaboration
Authors: Cunningham Robert , Olshfski Dorothy , Abdelrazek Reem
Published: November 2008

Collaboration is a warm, friendly word currently used to describe a cooperative manager—subordinate relationship. In this study, the authors first specify a meaning for collaboration and then, from stories told by competent cabinet members at the state level, extract evidence of collaborative and directive managerial relationships in problem solving. Based on these stories, collaboration is usefully seen as one tool among several (directive, devolution, collaboration) rather than as a consistent manager style. Therefore, from the perspective of style, managerial behavior is more paradoxical than consistent. As a sidebar, devolution emerges as closer to directive behavior than to collaborative behavior as a way of relating to subordinates.
ATSDR evaluation of health effects of benzene and relevance to public health
Authors: Wilbur S , Wohlers D , Paikoff S , Keith LS , Faroon O
Published: November 2008

As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals found at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) sites that have the greatest public health impact. These profiles comprehensively summarize toxicological and environmental information. This article constitutes the release of portions of the Toxicological Profile for Benzene. The primary purpose of this article is to provide public health officials, physicians, toxicologists, and other interested individuals and groups with an overall perspective on the toxicology of benzene. It contains descriptions and evaluations of toxicological studies and epidemiological investigations and provides conclusions, where possible, on the relevance of toxicity and toxicokinetic data to public health.
Tainted Money and Charity
Authors: Morris Donald
Published: November 2008

This article examines the right of a 501(c)(3) organization to refuse an unrestricted cash donation, concluding that such right is generally illusory. If a charity disagrees with the donor on a moral issue, it may see nothing improper in turning away a would-be benefactor. When this occurs in the context of a 501(c)(3) organization, its exempt purpose requires looking beyond the conscience of the individuals making the decision. Specifically, the question of the organization's moral right to turn away funding occurs in the context of its pursuit of a legally sanctioned purpose. The organization's agreement with the IRS in seeking tax-exempt status produces a fiduciary responsibility with its stakeholders. These include donors, potential recipients of the organization's goods or services, taxpayers, and the government. Viewed from this perspective, turning down a gift, it is argued, is comparable to mismanagement in squandering scarce resources.
Financial development and economic growth in developing countries
Authors: Dawson P.J.
Published: November 2008

The hypothesis that financial development promotes economic growth in developing countries is largely supported by empirical studies, though contrary evidence also exists. This relationship is re-examined using annual panel data for 44 developing countries for 1974–2001. Three sources-of-growth equations, which are specified from aggregate production functions, are estimated: two are theoretically consistent, while the third uses a common proxy (DEPTH) for financial development. Results show conflicting evidence: the theoretically consistent models show a positive and statistically significant relationship between financial development and economic growth, whereas the proxy version shows the opposite. Measuring financial development appropriately appears critical for policy advice
Interleukin-6/STAT3 signaling regulates the ability of naive T cells to acquire B-cell help capacities
Authors: Eddahri Fouad , Denanglaire Sébastien , Bureau Fabrice , Spolski Rosanne , Leonard Warren J. , Leo Oberdan , Andris Fabienne
Published: November 2008

The conditions leading to the activation/differentiation of T-helper (Th) cells dedicated for B-cell antibody production are still poorly characterized. We now demonstrate that interleukin-6 (IL-6) promotes the differentiation of naive T lymphocytes into helper cells able to promote B-cell activation and antibody secretion. IL-6–driven acquisition of B-cell help capacity requires expression of the signal transducer and activator of transcription 3 (STAT3), but not STAT4 or STAT6 transcription factors, suggesting that the ability to provide help to B cells is not restricted to a well-defined Th1 or Th2 effector population. T cell–specific STAT3-deficient mice displayed reduced humoral responses in vivo that could not be related to an altered expansion of CXCR5-expressing helper T cells. IL-6 was shown to promote IL-21 secretion, a cytokine that was similarly found to promote the differentiation of naive T cells into potent B-cell helper cells. Collectively, these data indicate that the ability to provide B-cell help is regulated by IL-6/IL-21 through STAT3 activation, independently of Th1, Th2, Th17, or follicular helper T cell (TFH) differentiation.
Gypsy endogenous retrovirus maintains potential infectivity in several species of Drosophilids
Authors: Llorens Jose V , Clark Jonathan B , Martínez-Garay Isabel , Soriano Sirena , de Frutos Rosa , Martínez-Sebastián María J
Published: November 2008

Background

Sequences homologous to the gypsy retroelement from Drosophila melanogaster are widely distributed among drosophilids. The structure of gypsy includes an open reading frame resembling the retroviral gene env, which is responsible for the infectious properties of retroviruses.

Results

In this study we report molecular and phylogeny analysis of the complete env gene from ten species of the obscura group of the genus Drosophila and one species from the genus Scaptomyza.

Conclusion

The results indicate that in most cases env sequences could produce a functional Env protein and therefore maintain the infectious capability of gypsy in these species.
Good adherence to HAART and improved survival in a community HIV/AIDS treatment and care programme: the experience of The AIDS Support Organization (TASO), Kampala, Uganda
Authors: Abaasa Andrew M , Todd Jim , Ekoru Kenneth , Kalyango Joan N , Levin Jonathan , Odeke Emmanuel , Karamagi Charles AS
Published: November 2008

Background

Poor adherence to highly active antiretroviral therapy (HAART) may result in treatment failure and death. Most reports of the effect of adherence to HAART on mortality come from studies where special efforts are made to provide HAART under ideal conditions. However, there are few reports of the impact of non-adherence to HAART on mortality from community HIV/AIDS treatment and care programmes in developing countries. We therefore conducted a study to assess the effect of adherence to HAART on survival in The AIDS Support Organization (TASO) community HAART programme in Kampala, Uganda.

Methods

The study was a retrospective cohort of 897 patients who initiated HAART at TASO clinic, Kampala, between May 2004 and December 2006. A total of 7,856 adherence assessments were performed on the data. Adherence was assessed using a combination of self-report and pill count methods. Patients who took ≤ 95% of their regimens were classified as non-adherent. The data was stratified at a CD4 count of 50 cells/mm3. Kaplan Meier curves and Cox proportional hazards regression models were used in the analysis.

Results

A total of 701 (78.2%) patients had a mean adherence to ART of > 95%. The crude death rate was 12.2 deaths per 100 patient-years, with a rate of 42.5 deaths per 100 patient-years for non-adherent patients and 6.1 deaths per 100 patient-years for adherent patients. Non-adherence to ART was significantly associated with mortality. Patients with a CD4 count of less than 50 cells/mm3had a higher mortality (HR = 4.3; 95% CI: 2.22–5.56) compared to patients with a CD4 count equal to or greater than 50 cells/mm3(HR = 2.4; 95% CI: 1.79–2.38).

Conclusion

Our study showed that good adherence and improved survival are feasible in community HIV/AIDS programmes such as that of TASO, Uganda. However, there is need to support community HAART programmes to overcome the challenges of funding to provide sustainable supplies particularly of antiretroviral drugs; provision of high quality clinical and laboratory support; and achieving a balance between expansion and quality of services. Measures for the early identification and treatment of HIV infected people including home-based VCT and HAART should be strengthened.
Transplantation of genetically engineered cardiac fibroblasts producing recombinant human erythropoietin to repair the infarcted myocardium
Authors: Ruvinov Emil , Sharabani-Yosef Orna , Nagler Arnon , Einbinder Tom , Feinberg Micha S , Holbova Radka , Douvdevani Amos , Leor Jonathan
Published: November 2008

Background

Erythropoietin possesses cellular protection properties. The aim of the present study was to test the hypothesis that in situ expression of recombinant human erythropoietin (rhEPO) would improve tissue repair in rat after myocardial infarction (MI).

Methods and results

RhEPO-producing cardiac fibroblasts were generated ex vivo by transduction with retroviral vector. The anti-apoptotic effect of rhEPO-producing fibroblasts was evaluated by co-culture with rat neonatal cardiomyocytes exposed to H2O2-induced oxidative stress. Annexin V/PI assay and DAPI staining showed that compared with control, rhEPO forced expression markedly attenuated apoptosis and improved survival of cultured cardiomyocytes. To test the effect of rhEPO on the infarcted myocardium, Sprague-Dawley rats were subjected to permanent coronary artery occlusion, and rhEPO-producing fibroblasts, non-transduced fibroblasts, or saline, were injected into the scar tissue seven days after infarction. One month later, immunostaining identified rhEPO expression in the implanted engineered cells but not in controls. Compared with non-transduced fibroblasts or saline injection, implanted rhEPO-producing fibroblasts promoted vascularization in the scar, and prevented cell apoptosis. By two-dimensional echocardiography and postmortem morphometry, transplanted EPO-engineered fibroblasts did not prevent left ventricular (LV) dysfunction and adverse LV remodeling 5 and 9 weeks after MI.

Conclusion

In situ expression of rhEPO enhances vascularization and reduces cell apoptosis in the infarcted myocardium. However, local EPO therapy is insufficient for functional improvement after MI in rat.
Intracerebral atypical calcification in nongalenic pial arteriovenous fistula: a case report
Authors: Tabatabai Seyed Ali Fakhr , Zadeh Mehdi Zeinali , Habibi Zohreh , Meybodi Ali Tayebi , Hashemi Mohammad
Published: November 2008

Nongalenic intradural arteriovenous fistulas, although uncommon, are clinically important. Choosing the appropriate therapeutic approach has been a controversial issue within the last decade.

A 15-year-old male was presented with a calcified nongalenic arteriovenous fistula in the left parietal region, supplied by the left middle cerebral artery, and draining into the left lateral sinus. The patient was managed surgically with traditional clipping the feeder artery, along with piecemeal resection of the huge calcified mass. Although endovascular methods may be the treatments of choice in similar cases, in such huge calcified lesion, non-amenable to endovascular occlusion, open surgery seems to be preferred.
The utility of gravity and water-level monitoring at alluvial aquifer wells in southern Arizona
Authors: Pool D. R.
Published: November 2008

Coincident monitoring of gravity and water levels at 39 wells in southern Arizona indicate that water-level change might not be a reliable indicator of aquifer-storage change for alluvial aquifer systems. One reason is that water levels in wells that are screened across single or multiple aquifers might not represent the hydraulic head and storage change in a local unconfined aquifer. Gravity estimates of aquifer-storage change can be approximated as a one-dimensional feature except near some withdrawal wells and recharge sources. The aquifer storage coefficient is estimated by the linear regression slope of storage change (estimated using gravity methods) and water-level change. Nonaquifer storage change that does not percolate to the aquifer can be significant, greater than [Formula: see text], when water is held in the root zone during brief periods following extreme rates of precipitation. Monitor-ing of storage change using gravity methods at wells also can improve understanding of local hydrogeologic conditions. In the study area, confined aquifer conditions are likely at three wells where large water-level variations were accompanied by little gravity change. Unconfined conditions were indicated at 15 wells where significant water-level and gravity change were positively linearly correlated. Good positive linear correlations resulted in extremely large specific-yield values, greater than 0.35, at seven wells where it is likely that significant ephemeral streamflow infiltration resulted in unsaturated storage change. Poor or negative linear correlations indicate the occurrence of confined, multiple, or perched aquifers. Monitoring of a multiple compressible aquifer system at one well resulted in negative correlation of rising water levels and subsidence-corrected gravity change, which suggests that water-level trends at the well are not a good indicatior of overall storage change.
Neuronal programmed cell death induces glial cell division in the adultDrosophilabrain
Authors: Kato Kentaro , Awasaki Takeshi , Ito Kei
Published: November 2008

Although mechanisms that lead to programmed cell death (PCD) in neurons have been analysed extensively, little is known about how surrounding cells coordinate with it. Here we show that neuronal PCD in the Drosophilabrain induces glial cell division. We identified PCD in neurons and cell division in glia occurring in a consistent spatiotemporal manner in adult flies shortly after eclosion. Glial division was suppressed when neuronal PCD was inhibited by ectopic expression of the caspase inhibitor gene p35, indicating their causal relationship. Glia also responded to neural injury in a similar manner: both stab injury and degeneration of sensory axons in the brain caused by antennal ablation induced glial division. Eiger, a tumour necrosis factor superfamily ligand, appears to be a link between developmental PCD/neural injury and glial division, as glial division was attenuated in eiger mutant flies. Whereas PCD soon after eclosion occurred in eiger mutants as in the wild type, we observed excess neuronal PCD 2 days later, suggesting a protective function for Eiger or the resulting glial division against the endogenous PCD. In older flies, between 6 and 50 days after adult eclosion, glial division was scarcely observed in the intact brain. Moreover, 8 days after adult eclosion, glial cells no longer responded to brain injury. These results suggest that the life of an adult fly can be divided into two phases: the first week, as a critical period for neuronal cell death-associated glial division, and the remainder.