bluuebunny/crossref_metadata_2025 huggingface dataset:
Two Amino Acid Substitutions within the First External Loop of CCR5 Induce Human Immunodeficiency Virus-Blocking Antibodies in Mice and Chickens
Authors: Pastori Claudia , Clivio Alberto , Diomede Lorenzo , Consonni Roberto , De Mori Giacomo M. S. , Longhi Renato , Colombo Giorgio , Lopalco Lucia
Published: February 2008

Antibodies to the first loop (ECL1) of CCR5 have been identified in human immunodeficiency virus (HIV)-exposed uninfected individuals (ESN) and in HIV-positive nonprogressing subjects. Thus, these antibodies may confer resistance against HIV infection. To define which amino acids are involved in antibody binding to CCR5, we performed a peptide-scanning assay and studied the immunogenicity of peptides in animal models. A panel of synthetic peptides spanning the CCR5-ECL1 region and displaying glycine or alanine substitutions was assayed for antibody binding with a pool of natural anti-CCR5 antibodies. We used mice and chickens to study the immunogenicity of mutagenized peptide. Structural characterization by nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics simulations were performed to better understand the structural and conformational features of the mutagenized peptide. Amino acid substitutions in positions Ala95 and Ala96 (A95-A96) increased antibody-peptide binding compared to that of the wild-type peptide (Asp95-Phe96). The Ala95-96 peptide was shown to induce, in mice and chickens, antibodies displaying biological activity at very low concentrations. Strikingly, chicken antibodies to the Ala95-96 peptide specifically recognize human CCR5 molecules, downregulate receptors from lymphocytes, inhibit CCR5-dependent chemotaxis, and prevent infection by several R5 viruses, displaying 50% inhibitory concentrations of less than 3 ng/ml. NMR spectroscopy and molecular dynamics simulations proved the high flexibility of isolated epitopes and suggested that A95-A96substitutions determine a slightly higher tendency to generate helical conformations combined with a lower steric hindrance of the side chains in the peptides. These findings may be relevant to the induction of strong and efficient HIV-blocking antibodies.
Venezuelan Equine Encephalitis Virus Capsid Protein Inhibits Nuclear Import in Mammalian but Not in Mosquito Cells
Authors: Atasheva Svetlana , Garmashova Natalia , Frolov Ilya , Frolova Elena
Published: February 2008

Venezuelan equine encephalitis virus (VEEV) represents a continuous public health threat in the United States. It has the ability to cause fatal disease in humans and in horses and other domestic animals. We recently demonstrated that replicating VEEV interferes with cellular transcription and uses this phenomenon as a means of downregulating a cellular antiviral response. VEEV capsid protein was found to play a critical role in this process, and its ∼35-amino-acid-long peptide, fused with green fluorescent protein, functioned as efficiently as did the entire capsid. We detected a significant fraction of VEEV capsid associated with nuclear envelope, which suggested that this protein might regulate nucleocytoplasmic trafficking. In this study, we demonstrate that VEEV capsid and its N-terminal sequence efficiently inhibit multiple receptor-mediated nuclear import pathways but have no effect on the passive diffusion of small proteins. The capsid protein of the Old World alphavirus Sindbis virus and the VEEV capsid, with a previously defined frameshift mutation, were found to have no detectable effect on nuclear import. Importantly, the VEEV capsid did not noticeably interfere with nuclear import in mosquito cells, and this might play a critical role in the ability of the virus to develop a persistent, life-long infection in mosquito vectors. These findings demonstrate a new aspect of VEEV-host cell interactions, and the results of this study are likely applicable to other New World alphaviruses, such as eastern and western equine encephalitis viruses.
Cone moisture and relative humidity effects on seed release from lodgepole pine cones from Alberta
Authors: Hellum A. K.
Published: February 2008

Cones from two stands of lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) from southwestern Alberta were bulked for approximately 10 trees per location. The effects of cone moisture content and relative humidities (RH) on seed release within the extraction kiln were noted.Cone moisture content was the most important factor for seed extraction and the greater the moisture loss the more seed was released. Kiln RH of 10, 15, and 20% were equally effective, as was dropping the RH from 20 to 10% during extraction. A final RH of < 10% probably is required for full seed release.
Heterogeneity of decomposition and nutrient dynamics of oak (Quercus) logs during the first 2 years of decomposition
Authors: Schowalter T.D.
Published: February 2008

Decomposition of oak (Quercus spp.) logs (25–35 cm diameter, 3 m long) was compared among log substrates in Oregon, Minnesota, Kansas, and North Carolina during the first 2 years on the ground. Decomposition rates (k) for integrated logs averaged 0.28 ± 0.04 year−1 (mean ± 1 SD)) during this initial period. Decomposition reflected qualitative differences among log substrates (outer and inner bark, sapwood and heartwood). Inner bark had the highest nutritional quality and was the focus of insect and microbial activity during this early stage of decomposition; only 20% of initial mass remained after 2 years (k = 0.59 ± 0.15 year−1). Sapwood decayed more slowly than heartwood, with an overall decay rate of 0.20 ± 0.15 year−1). Heartwood lost 50% of its mass during the 1st year, but showed no further loss during the 2nd year, for an overall decay rate of 0.31 ± 0.05 year−1. Nutrient content generally declined during decomposition, but P accumulated in heartwood and Na accumulated in sapwood and heartwood during the 2nd year. Results indicate that decomposition of whole logs integrates different decomposition rates and lag times (i.e., time prior to initiation of decomposition) among log substrates varying in qualitative factors. Multiple-exponential models may be necessary to predict rates and sources of carbon and nutrient release to the atmosphere and soil.
Cycling of acid and base cations in deciduous stands of Huntington Forest, New York, and Turkey Lakes, Ontario
Authors: Foster N.W. , Mitchell M.J. , Morrison I.K. , Shepard J.P.
Published: February 2008

Annual nutrient fluxes within two forests exposed to acidic deposition were compared for a 1-year period. Calcium (Ca2+) was the dominant cation in throughfall and soil solutions from tolerant hardwood dominated Spodosols (Podzols) at both Huntington Forest (HF), New York, and the Turkey Lakes watershed (TLW), Ontario. There was a net annual export of Ca2+ and Mg2+ from the TLW soil, whereas base cation inputs in precipitation equaled outputs at HF. In 1986, leaching losses of base cations were five times greater at TLW than at HF. A higher percentage of the base cation reserves was leached from the soil at TLW (5%) than at HF (1%). Relative to throughfall, aluminum concentrations increased in forest-floor and mineral-soil solutions, especially at HF. The TLW soil appears more sensitive to soil acidification. Deposited atmospheric acidity, however, was small in comparison with native soil acidity (total and exchangeable) and the reserves of base cations in each soil. Soil acidity and base saturation, therefore, are likely only to change slowly.
Optimal sampling strategies for weighted linear regression estimation
Authors: Schreuder H.T. , Ouyang Z.
Published: February 2008

Our strong effort to find an optimal sampling strategy that was clearly superior to other strategies for a range of linearity conditions and variance structures for linear models showed that several sampling strategies turned out to be equally efficient. Each of these stratified the population to the maximum extent feasible, i.e., used n strata based on a covariate. Which of two ways of stratification to use and how units in each stratum were selected (simple random sampling or sampling with probability proportional to size) did not seem to matter much. Two regression estimators, one considering both probability and variance weights (Ŷgr) and one considering only probability weights (Ŷpi), are preferred estimators with the five efficient sampling selection schemes that select one unit per stratum with either equal or unequal probability sampling. The bootstrap variance estimator is generally the least biased, yet conservative, variance estimator and yields reliable coverage rates with 95% confidence intervals for most populations studied.
Focal point seed zones: site-specific seed zone delineation using geographic information systems
Authors: Parker William H.
Published: February 2008

A new site-specific approach to defining seed zones in North American conifers is described. Using focal point seed zones, an individual site to be reforested becomes the focal point, and a unique seed zone is established for that site as needed. This approach depends upon (i) obtaining good comparative data in adaptive characteristics from throughout the range to beregenerated based upon a series of short-term growth tests in a common garden and (or) greenhouse and (ii) graphic analysis of multivariate summary scores by geographic information systems software to delimit boundaries of unique seed zones for any location to be reforested. A sample focal point seed zone is delineated for jack pine (Pinusbanksiana Lamb.) reforestation of a site in northern Ontario. This approach has considerable potential to help prevent decreased growth and yield due to the planting of maladapted seed.
Auxin: The Looping Star in Plant Development
Authors: Benjamins René , Scheres Ben
Published: February 2008

The phytohormone auxin is a key factor in plant growth and development. Forward and reverse genetic strategies have identified important molecular components in auxin perception, signaling, and transport. These advances resulted in the identification of some of the underlying regulatory mechanisms as well as the emergence of functional frameworks for auxin action. This review focuses on the feedback loops that form an integrative part of these regulatory mechanisms.
The Role of Glutathione in Photosynthetic Organisms: Emerging Functions for Glutaredoxins and Glutathionylation
Authors: Rouhier Nicolas , Lemaire Stéphane D. , Jacquot Jean-Pierre
Published: February 2008

Glutathione, a tripeptide with the sequence γ-Glu-Cys-Gly, exists either in a reduced form with a free thiol group or in an oxidized form with a disulfide between two identical molecules. We describe here briefly the pathways involved in the synthesis, reduction, polymerization, and degradation of glutathione, as well as its distribution throughout the plant and its redox buffering capacities. The function of glutathione in xenobiotic and heavy metal detoxification, plant development, and plant-pathogen interactions is also briefly discussed. Several lines of evidence indicate that glutathione and glutaredoxins (GRXs) are implicated in the response to oxidative stress through the regeneration of enzymes involved in peroxide and methionine sulfoxide reduction. Finally, emerging functions for plant GRXs and glutathione concern the regulation of protein activity via glutathionylation and the capacity of some GRXs to bind iron sulfur centers and for some of them to transfer FeS clusters into apoproteins.
Plant Proteases: From Phenotypes to Molecular Mechanisms
Authors: van der Hoorn Renier A. L.
Published: February 2008

Plant genomes encode hundreds of proteases, which represent dozens of unrelated families. The biological role of these proteases is mostly unknown, but mutant alleles, gene silencing, and overexpression studies have provided phenotypes for a growing number of proteases. The aim of this review is to show the diversity of the processes that are regulated by proteases, and to summarize the current knowledge of the underlying molecular mechanisms. The emerging picture is that plant proteases are key regulators of a striking variety of biological processes, including meiosis, gametophyte survival, embryogenesis, seed coat formation, cuticle deposition, epidermal cell fate, stomata development, chloroplast biogenesis, and local and systemic defense responses. The functional diversity correlates with the molecular data: Proteases are specifically expressed in time and space and accumulate in different subcellular compartments. Their substrates and activation mechanisms are elusive, however, and represent a challenging topic for further research.
A Genetic Regulatory Network in the Development of Trichomes and Root Hairs
Authors: Ishida Tetsuya , Kurata Tetsuya , Okada Kiyotaka , Wada Takuji
Published: February 2008

Trichomes and root hairs differentiate from epidermal cells in the aerial tissues and roots, respectively. Because trichomes and root hairs are easily accessible, particularly in the model plant Arabidopsis, their development has become a well-studied model of cell differentiation and growth. Molecular genetic analyses using Arabidopsis mutants have demonstrated that the differentiation of trichomes and root hair/hairless cells is regulated by similar molecular mechanisms. Transcriptional complexes regulate differentiation into trichome cells and root hairless cells, and formation of the transcriptional complexes is inhibited in neighboring cells. Control of cell growth after fate determination has also been analyzed using Arabidopsis mutants. The progression of endoreduplication cycles, reorientation of microtubules, and organization of the actin cytoskeleton play important roles in trichome growth. Various cellular components such as ion channels, the actin cytoskeleton, microtubules and cell wall materials, and intracellular signal transduction act to establish and maintain root hair tip growth.
How Translocons Select Transmembrane Helices
Authors: White Stephen H. , von Heijne Gunnar
Published: February 2008

Like all cellular proteins, membrane proteins are synthesized by ribosomes. But unlike their soluble counterparts, highly hydrophobic membrane proteins require auxiliary machineries to prevent aggregation in aqueous cellular compartments. The principal machine is the translocon, which works in concert with ribosomes to manage the orderly insertion of α-helical membrane proteins directly into the endoplasmic reticulum membrane of eukaryotes or into the plasma membrane of bacteria. In the course of insertion, membrane proteins come into thermodynamic equilibrium with the lipid membrane, where physicochemical interactions determine the final three-dimensional structure. Much progress has been made during the past several years toward understanding the physical chemistry of membrane protein stability, the structure of the translocon machine, and the mechanisms by which the translocon selects and inserts transmembrane helices. We review this progress and consider the connection between the physical principles of membrane protein stability and translocon selection of transmembrane helices.
Intermediate filaments in smooth muscle
Authors: Tang Dale D.
Published: February 2008

The intermediate filament (IF) network is one of the three cytoskeletal systems in smooth muscle. The type III IF proteins vimentin and desmin are major constituents of the network in smooth muscle cells and tissues. Lack of vimentin or desmin impairs contractile ability of various smooth muscle preparations, implying their important role for smooth muscle force development. The IF framework has long been viewed as a fixed cytostructure that solely provides mechanical integrity for the cell. However, recent studies suggest that the IF cytoskeleton is dynamic in mammalian cells in response to various external stimulation. In this review, the structure and biological properties of IF proteins in smooth muscle are summarized. The role of IF proteins in the modulation of smooth muscle force development and redistribution/translocation of signaling partners (such as p130 Crk-associated substrate, CAS) is depicted. This review also summarizes our latest understanding on how the IF network may be regulated in smooth muscle.
Identification of FXYD protein genes in a teleost: tissue-specific expression and response to salinity change
Authors: Tipsmark Christian Kølbæk
Published: February 2008

It is increasingly clear that alterations in Na+-K+-ATPase kinetics to fit the demands in specialized cell types is vital for the enzyme to execute its different physiological roles in diverse tissues. In addition to tissue-dependent expression of isoforms of the conventional subunits, α and β, auxiliary FXYD proteins appear to be essential regulatory components. The present study identified genes belonging to this family in Atlantic salmon by analysis of expressed sequence tags. Based on the conserved domain of these small membrane proteins, eight expressed FXYD isoforms were identified. Phylogenetic analysis suggests that six isoforms are homologues to the previously identified FXYD2, FXYD5, FXYD6, FXYD7, FXYD8, and FXYD9, while two additional isoforms were found (FXYD11 and FXYD12). Using quantitative PCR, tissue-dependent expression of the different isoforms was analyzed in gill, kidney, intestine, heart, muscle, brain, and liver. Two isoforms were expressed in several tissues (FXYD5 and FXYD9), while six isoforms were distributed in a discrete manner. In excitable tissues, two isoforms were highly expressed in brain (FXYD6 and FXYD7) and one in skeletal muscle (FXYD8). In osmoregulatory tissues, one isoform was expressed predominantly in gill (FXYD11), one in kidney (FXYD2), and one equally in kidney and intestine (FXYD12). Expression of several FXYD genes in kidney and gill differed between fresh water and seawater salmon, suggesting significance during osmoregulatory adaptations. In addition to identifying novel FXYD isoforms, these studies are the first to show the tissue dependence in their expression and modulation by salinity in any teleosts.
Whole body norepinephrine kinetics in ANG II-salt hypertension in the rat
Authors: King Andrew J. , Novotny Martin , Swain Greg M. , Fink Gregory D.
Published: February 2008

The purpose of this study was to investigate total body norepinephrine (NE) kinetics as an index of global sympathetic nervous system (SNS) outflow in a rat model of chronic ANG II-salt hypertension. Male Sprague-Dawley rats fed a 0.4% (normal salt, NS) or 2% (HS) NaCl diet were instrumented with arterial and venous catheters. After 5 days of recovery and a 3-day control period, ANG II (150 ng·kg−1·min−1) was given subcutaneously by minipump for 14 days. Plasma NE levels and total body NE spillover and clearance were determined on control day 3 and ANG II infusion days 7 and 14 using radioisotope dilution principles. To perform this analysis, 3H-NE and NE were measured in arterial plasma after a 90-min infusion of tracer amounts of 3H-NE. Mean arterial pressure (MAP) was similar during the control period in NS and HS rats; however, MAP increased to a higher level in HS rats. During the control period, plasma NE tended to be lower in rats on HS, whereas NE clearance tended to be higher in HS rats. As a result NE spillover was similar in NS and HS rats during the control period. In NS rats, plasma NE, NE spillover, and NE clearance were unchanged by ANG II. In contrast, in rats on the HS diet, plasma NE and NE spillover increased during ANG II infusion, whereas NE clearance was unchanged. In conclusion, a HS diet alone or ANG II infusion in animals fed NS do not affect global sympathetic outflow. However, the additional hypertensive response to ANG II in animals fed HS is accompanied by SNS activation.
Functional characterization of mouse urea transporters UT-A2 and UT-A3 expressed in purifiedXenopus laevisoocyte plasma membranes
Authors: MacIver Bryce , Smith Craig P. , Hill Warren G. , Zeidel Mark L.
Published: February 2008

Urea is a small solute synthesized by many terrestrial organisms as part of the catabolism of protein. In mammals it is transported across cellular membranes by specific urea transporter (UT) proteins that are the products of two separate, but closely related genes, referred to as UT-A and UT-B. Three major UT-A isoforms are found in the kidney, namely UT-A1, UT-A2, and UT-A3. UT-A2 is found in the thin, descending limb of the loop of Henle, whereas UT-A1 and UT-A3 are concentrated in the inner medullary collecting duct. UT-A2 and UT-A3 effectively represent two halves of the whole UT-A gene and, when joined together by 73 hydrophilic amino acids, constitute UT-A1. A biophysical characterization of mouse UT-A2 and UT-A3 was undertaken by expression in Xenopus laevis oocytes and subsequent preparation of highly enriched plasma membrane vesicles for use in stopped-flow fluorometry. Both isoforms were found to be highly specific for urea, and did not permeate water, ammonia, or other molecules closely related to urea (formamide, acetamide, methylurea, and dimethylurea). Single transporter flux rates of 46,000 ± 10,000 and 59,000 ± 15,000 (means ± SE) urea molecules/s/channel for UT-A2 and UT-A3, respectively, were obtained. Overall, the UT-A2 and UT-A3 isoforms appear to have identical functional kinetics.
Mediation of angiotensin II-induced Ca2+signaling by polycystin 2 in glomerular mesangial cells
Authors: Du Juan , Ding Min , Sours-Brothers Sherry , Graham Sarabeth , Ma Rong
Published: February 2008

Ca+influx across the plasma membrane is a major component of mesangial cell (MC) response to vasoconstrictors. Polycystin 2 (PC2), the protein product of the gene mutated in type 2 autosomal dominant polycystic kidney disease, has been shown to function as a nonselective cation channel in a variety of cell types. The present study was performed to test the hypothesis that PC2 and its binding partners constitute a Ca2+-permeable channel and contribute to ANG II-induced Ca2+signaling in MCs. Western blot and immunocytochemistry showed PC2 expression in cultured human MCs. The existence of PC2 in MCs was further confirmed by immunohistochemsitry in rat kidney sections. Coimmunoprecipitation displayed a selective interaction of PC2 with canonical transient receptor potential (TRPC) proteins TRPC1 and TRPC4. Cell-attached patch-clamp experiments revealed that ANG II-induced membrane currents were enhanced by overexpression of pkd2 but significantly inhibited by knock down of pkd2, 30 μM Gd3+(a PC2 channel blocker), and dominant-negative pkd2 mutant (pkd2-D511V). Corresponding to the increase in channel currents, ANG II stimulation increased expression of PC2 on the cell surface of MCs and interaction with TRPC1 and TRPC4. Furthermore, ANG II-induced MC contraction was significantly reduced in pkd2-knocked down MCs. These data suggest that PC2 selectively assembles with TRPC1 and TRPC4 to form channel complexes mediating ANG II-induced Ca2+responses in MCs.
Glucose Metabolism, Insulin Resistance, and Renal Pathology in Non-Diabetic Chronic Kidney Disease
Authors: Ikee Ryota , Hamasaki Yoshifumi , Oka Machiko , Maesato Kyoko , Mano Tsutomu , Moriya Hidekazu , Ohtake Takayasu , Kobayashi Shuzo
Published: February 2008

Background: The relation between insulin resistance and atherosclerosis is widely recognized, but it remains unknown whether glucose metabolism/insulin resistance is related to renal pathology in humans. Methods: We quantitatively evaluated pathological changes in the glomeruli, tubulointerstitium, and vessels in renal biopsy specimens from 23 patients with non-diabetic chronic kidney disease (CKD), all of whom took a 75-gram oral glucose tolerance test. We correlated the renal pathological changes with fasting plasma glucose (FPG), fasting plasma insulin, 2-hour plasma glucose (2-h PG), 2-hour plasma insulin (2-h PI), homeostasis model assessment of insulin resistance (HOMA-IR), and body mass index. Results: HOMA-IR exceeded 1.73 in 11 patients (47.8%), and 2-h PI exceeded 64.0 µU/ml in 14 (60.9%). FPG significantly correlated with interstitial fibrosis (r = 0.532, p = 0.009). The significance was marginal in the correlation between FPG and tubular atrophy and arterio-arteriolosclerosis. Statistically significant correlation was also found between 2-h PG and arterio-arteriolosclerosis (r = 0.422, p = 0.04) and between HOMA-IR and interstitial fibrosis (r = 0.416, p = 0.04). Conclusion: Although precise mechanisms remain unknown, glucose metabolism/insulin resistance seem to play pathogenic roles in formation and progression of renal pathological changes, especially tubulointerstitial and vascular lesions, in non-diabetic CKD.
Cochlear Implantation Outcome in Prelingually Deafened Young Adults
Authors: Santarelli Rosamaria , De Filippi Roberta , Genovese Elisabetta , Arslan Edoardo
Published: February 2008

The outcome of cochlear implantation in patients with deafness of prelingual onset is largely unpredictable due to high individual variability. This study evaluated speech perception performances in a group of 18 prelingually deafened subjects (aged 13–30 years) which was homogeneous with respect to duration of deafness, hearing aid use before cochlear implantation, mode of communication and administration of auditory-oral speech therapy. Word discrimination length, word and sentence identification, phoneme identification and word and sentence recognition were tested before cochlear implantation and at 6 months, 1, 2 and 3 years of cochlear implant use. Scores on all tests significantly improved after cochlear implantation, although mean values were lower compared to those achieved by postlingually deafened patients. Speech performances on both word and sentence recognition continued to increase over time also beyond 1 year after cochlear implantation. Moreover, scores on sentence recognition tests were significantly higher compared to disyllabic words at 3 years of cochlear implant use. The presence of an auditory input delivered by hearing aids before cochlear implantation associated with auditory-oral therapy and a good level of education may positively influence the cochlear implant outcome in prelingually deafened adults.
Time Trends in Oligodendroglial and Astrocytic Tumor Incidence
Authors: McCarthy Bridget J. , Propp Jennifer M. , Davis Faith G. , Burger Peter C.
Published: February 2008

Background: We hypothesized that the incidences of oligodendrogliomas, anaplastic oligodendrogliomas, and mixed gliomas have significantly increased from the early 1990s forward, while the incidences of anaplastic and grade II astrocytic tumors have significantly decreased. Methods: Data for the years 1973–2004 from the Surveillance, Epidemiology and End Results (SEER) public-use data and for 1985–2004 from six collaborating registries of the Central Brain Tumor Registry of the US (CBTRUS) were obtained. SEER*Stat was used to estimate age-adjusted incidence trends and annual percent change (APC) for selected histologies. Joinpoint regression was used to identify sharp changes in incidences occurring over time. Results: Using CBTRUS data, the incidences (per 100,000 person-years) of oligodendrogliomas (APC = 4.7), mixed gliomas (APC = 3.9) and anaplastic oligodendrogliomas (APC = 12.5) have all increased over time, while the incidences of astrocytoma not otherwise specified (APC = –8.1) and fibrillary astrocytoma (APC = –2.1) have decreased. Restricting the analyses to later years (1992–2004) using SEER data shows the incidence of oligodendrogliomas leveling off (APC = 0.5), while joinpoint analyses demonstrate a decreasing trend after 1998. Conclusions: This study has demonstrated that increases in oligodendroglial tumor incidence correspond to decreases in astrocytic tumor incidence over the same time period. Minimizing misclassification of glial tumors will be essential for accurately assessing incidence, survival, and mortality rates, as well as for identifying homogeneous subgroups for epidemiologic and treatment studies.
Origin of the Springtime Westerly Bias in Equatorial Atlantic Surface Winds in the Community Atmosphere Model Version 3 (CAM3) Simulation
Authors: Chang Ching-Yee , Nigam Sumant , Carton James A.
Published: February 2008

This study makes the case that westerly bias in the surface winds of the National Center for Atmospheric Research (NCAR) Community Atmosphere Model, version 3 (CAM3), over the equatorial Atlantic in boreal spring has its origin in the rainfall (diabatic heating) bias over the tropical South American continent. The case is made by examination of the spatiotemporal evolution of regional precipitation and wind biases and by dynamical diagnoses of the westerly wind bias from experiments with a steady, linearized dynamical core of an atmospheric general circulation model. Diagnostic modeling indicates that underestimating rainfall over the eastern Amazon region can lead to the westerly bias in equatorial Atlantic surface winds.

The study suggests that efforts to reduce coupled model biases, especially seasonal ones, must target continental biases, even in the deep tropics where ocean–atmosphere interaction generally rules.
Sub-hourly simulation of residential ground coupled heat pump systems
Authors: Kummert Michaël , Bernier Michel
Published: February 2008

Residential Ground Coupled Heat Pump systems are usually characterised by an ON/OFF behaviour of the heat pump with typical cycling frequencies of 1—4 cycles per hour. The ground loop fluid pump has the same ON/OFF behaviour and the borehole heat exchanger operates either in full flow or no flow conditions. Typical hourly simulations of GCHP systems use steady-state models for the heat pump and the borehole fluid (transient models being used for buildings and heat transfer in the ground). This paper reviews the models used in typical hourly simulations as well as transient models that are available and compares the results obtained using the two classes of models within the TRNSYS simulation environment. Both the long-term energy performance and the optimum system design are compared. It is shown that using steady-state models leads to an overestimation of the energy use that ranges from a few percents with oversized borehole heat exchangers to 75% for undersized exchangers. A simple Life Cycle Cost analysis shows that using steady-state models can lead to selecting a very different design than the one that would have been selected using dynamic models.
Factors Associated With Advance Care Planning Among Older Adults in Southwest Florida
Authors: Black Kathy , Reynolds Sandra L. , Osman Hana
Published: February 2008

As the nation's population continues to age, many older adults will face care needs that can be anticipated in advance. However, little is known about older adults' advance care plans and the characteristics of those who plan. This study used a stratified random sampling design to survey older adults (n = 203) in the state of Florida regarding their attitudes toward future care and planning behavior in social-environmental, health, and financial domains. Regression analyses were conducted to determine factors most predictive of older adults' attitudes toward future care and planning behavior by domain. Results suggests that gender, age, and functional status predict greater planning behavior and more accepting attitudes toward long-term care, whereas living alone and poor health status are associated with less advance care planning behavior and greater nonaccepting attitudes. Factors associated with a greater likelihood to have advance care planning documents and concrete plans for future care include increased age, higher educational attainment, and female gender.
Addressing Fidelity in Evidence-Based Health Promotion Programs for Older Adults
Authors: Frank Janet C. , Coviak Cynthia P. , Healy Tara C. , Belza Basia , Casado Banghwa Lee
Published: February 2008

This article addresses health behavior change program fidelity using the five components of fidelity from the National Institute of Aging's Behavior Change Consortia: fidelity in design, training, delivery, receipt, and enactment. Fidelity is a key issue in successful translational research projects into community settings. The authors examine four programs sponsored by the Administration on Aging that target health behavior change in physical activity (EnhanceFitness), chronic disease self-management (Partners on the PATH [Personal Action Toward Health]), fear of falling and falls prevention (Matter of Balance), and depression management (Healthy IDEAS). This article (a) describes the tools and strategies used by these projects to track and enhance fidelity to the core elements of the original intervention studies, (b) compares and contrasts each project's mechanisms of fidelity, (c) provides examples of fidelity outcomes, and (d) discusses themes and lessons learned that may be useful to others in developing the “next generation” of program translation.
Detection Strategies for Malingering With the Miller Forensic Assessment of Symptoms Test
Authors: Vitacco Michael J. , Jackson Rebecca L. , Rogers Richard , Neumann Craig S. , Miller Holly A. , Gabel Jason
Published: February 2008

Two of the most widely used measures for the assessment of malingering in forensic populations are the Miller Forensic Assessment of Symptoms Test (M-FAST) and the Structured Interview of Reported Symptoms (SIRS). The underlying dimensions of the SIRS have been well established in the literature, but the structure of the M-FAST remains relatively untested. Understanding of its dimensions is critical for construct validity and guiding its proper use. Confirmatory factor analysis was used to provide evidence of a single parsimonious malingering factor to account for the covariation of the M-FAST items in a sample of 244 forensic patients. In addition, the model was cross-validated with an independent sample of 210 forensic patients. Finally, the M-FAST factor was modeled in conjunction with two factors of the SIRS. Results provide further validation of the underlying detection strategy found in the M-FAST.
Platelet-derived CD154 enables T-cell priming and protection against Listeria monocytogenes challenge
Authors: Elzey Bennett D. , Schmidt Nathan W. , Crist Scott A. , Kresowik Timothy P. , Harty John T. , Nieswandt Bernhard , Ratliff Timothy L.
Published: February 2008

Collagen exposure in tissue activates platelets, initiates wound healing, and modulates adaptive immunity. In this report, data are presented to demonstrate a requirement for platelet-derived CD154 for both collagen-induced augmentation of T-cell immunity and induction of pro-tective immunity to Listeria challenge. Specifically, we demonstrate that Ad5 encoding the membrane-bound form of ovalbumin (Ad5-mOVA) delivered in collagen induces higher ovalbumin-specific cytotoxic T lymphocyte (CTL) activity in a dose-dependent manner compared with Ad5-mOVA delivered in PBS. Increased CTL activity was dependent on the ability of platelets to respond to collagen and to express CD154. Furthermore, mice immunized with low-dose Ad5-mOVA in collagen were able to control a challenge of Listeria monocytogenes recombinant for ovalbumin expression (Lm-OVA), whereas mice immunized with low-dose Ad5-mOVA in PBS were not. These data indicate that in a physiologic setting that mimics wounding, platelets perform a sentinel function when antigen dose is too low to provoke an efficient immune response, and can enhance the generation of antigen-specific CD8 T cells that are functionally relevant to the host.
Intracellular survival and vascular cell-to-cell transmission of Porphyromonas gingivalis
Authors: Li Ling , Michel Raynald , Cohen Joshua , DeCarlo Arthur , Kozarov Emil
Published: February 2008

Background

Porphyromonas gingivalis is associated with periodontal disease and invades different cell types including epithelial, endothelial and smooth muscle cells. In addition to P. gingivalis DNA, we have previously identified live invasive bacteria in atheromatous tissue. However, the mechanism of persistence of this organism in vascular tissues remains unclear. Therefore, the objective of this study was to analyze the ability of intracellular P. gingivalis to persist for extended periods of time, transmit to and possibly replicate in different cell types.

Results

Using antibiotic protection assays, immunofluorescent and laser confocal microscopy, we found that after a prolonged intracellular phase, while P. gingivalis can still be detected by immunostaining, the intracellular organisms lose their ability to be recovered in vitro. Surprisingly however, intracellular P. gingivalis could be recovered in vitro upon co incubation with fresh vascular host cells. We then demonstrated that the organism was able to exit the initially infected host cells, then enter and multiply in new host cells. Further, we found that cell-to-cell contact increased the transmission rate but was not required for transmission. Finally, we found that the invasion of new host cells allowed P. gingivalis to increase its numbers.

Conclusion

Our results suggest that the persistence of vascular tissue-embedded P. gingivalis is due to its ability to transmit among different cell types. This is the first communication demonstrating the intercellular transmission as a likely mechanism converting latent intracellular bacteria from state of dormancy to a viable state allowing for persistence of an inflammatory pathogen in vascular tissue.
Epidemiology and outcomes of community-onset methicillin-susceptible Staphylococcus aureusbacteraemia in a university hospital in Singapore
Authors: Chia Jonathan Wei-Zhong , Hsu Li-Yang , Chai Louis Yi-Ann , Tambyah Paul Ananth
Published: February 2008

Background

Methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia remains a condition associated with considerable morbidity and mortality worldwide. It is a common but little-studied problem outside of Europe and North America.

Methods

A single-centre retrospective case series profiling all patients with community onset-MSSA bacteraemia presenting between March 2005 and February 2006 to a tertiary acute-care university hospital in Singapore. In addition to epidemiological and clinical data collection, risk factors for complicated bacteremia and attributable mortality were analysed.

Results

A total of 100 patients met the case definition. Patients were more likely to be male (65%) and below 65 years of age (69%). Seventeen patients were intravenous drug abusers, while 38 had diabetes mellitus. There were 18 cases of endocarditis, with 11 occurring in intravenous buprenorphine abusers. Attributable mortality was 11%, and 46% of patients developed complicated bacteremia. On multivariate analysis, age > 65 years and presence of chronic pulmonary disease were the only significant risk factors for the former, while valvular heart disease was a significant risk factor for the latter.

Conclusion

MSSA bacteraemia is associated with a significant risk of serious complications in Singapore. Other Asian cities should be alert to the risk factors for adverse outcomes for this important cause of morbidity and mortality.
Finding exonic islands in a sea of non-coding sequence: splicing related constraints on protein composition and evolution are common in intron-rich genomes
Authors: Warnecke Tobias , Parmley Joanna L , Hurst Laurence D
Published: February 2008

Background

In mammals, splice-regulatory domains impose marked trends on the relative abundance of certain amino acids near exon-intron boundaries. Is this a mammalian particularity or symptomatic of exonic splicing regulation across taxa? Are such trends more common in species that a priori have a harder time identifying exon ends, that is, those with pre-mRNA rich in intronic sequence? We address these questions surveying exon composition in a sample of phylogenetically diverse genomes.

Results

Biased amino acid usage near exon-intron boundaries is common throughout the metazoa but not restricted to the metazoa. There is extensive cross-species concordance as to which amino acids are affected, and reduced/elevated abundances are well predicted by knowledge of splice enhancers. Species expected to rely on exon definition for splicing, that is, those with a higher ratio of intronic to coding sequence, more introns per gene and longer introns, exhibit more amino acid skews. Notably, this includes the intron-rich basidiomycete Cryptococcus neoformans, which, unlike intron-poor ascomycetes (Schizosaccharomyces pombe, Saccharomyces cerevisiae), exhibits compositional biases reminiscent of the metazoa. Strikingly, 5 prime ends of nematode exons deviate radically from normality: amino acids strongly preferred near boundaries are strongly avoided in other species, and vice versa. This we suggest is a measure to avoid attracting trans-splicing machinery.

Conclusion

Constraints on amino acid composition near exon-intron boundaries are phylogenetically widespread and characteristic of species where exon localization should be problematic. That compositional biases accord with sequence preferences of splice-regulatory proteins and are absent in ascomycetes is consistent with selection on exonic splicing regulation.
R-spondin 2 is required for normal laryngeal-tracheal, lung and limb morphogenesis
Authors: Bell Sheila M. , Schreiner Claire M. , Wert Susan E. , Mucenski Michael L. , Scott William J. , Whitsett Jeffrey A.
Published: February 2008

Herein, we demonstrate that Lrp6-mediated R-spondin 2 signaling through the canonical Wnt pathway is required for normal morphogenesis of the respiratory tract and limbs. We show that the footless insertional mutation creates a severe hypomorphic R-spondin 2 allele (Rspo2Tg). The predicted protein encoded by Rspo2Tg neither bound the cell surface nor activated the canonical Wnt signaling reporter TOPFLASH. Rspo2 activation of TOPFLASH was dependent upon the second EGF-like repeat of Lrp6. Rspo2Tg/Tg mice had severe malformations of laryngeal-tracheal cartilages, limbs and palate, and lung hypoplasia consistent with sites of Rspo2 expression. Rspo2Tg/Tg lung defects were associated with reduced branching, a reduction in TOPGAL reporter activity, and reduced expression of the downstream Wnt target Irx3. Interbreeding the Rspo2Tg and Lrp6- alleles resulted in more severe defects consisting of marked lung hypoplasia and absence of tracheal-bronchial rings, laryngeal structures and all limb skeletal elements.
Spliced leader trans-splicing in the nematode Trichinella spiralis uses highly polymorphic, noncanonical spliced leaders
Authors: Pettitt Jonathan , Müller Berndt , Stansfield Ian , Connolly Bernadette
Published: February 2008

The trans-splicing of short spliced leader (SL) RNAs onto the 5′ ends of mRNAs occurs in a diverse range of taxa. In nematodes, all species so far characterized utilize a characteristic, conserved spliced leader, SL1, as well as variants that are employed in the resolution of operons. Here we report the identification of spliced leader trans-splicing in the basal nematode Trichinella spiralis, and show that this nematode does not possess a canonical SL1, but rather has at least 15 distinct spliced leaders, encoded by at least 19 SL RNA genes. The individual spliced leaders vary in both size and primary sequence, showing a much higher degree of diversity compared to other known trans-spliced leaders. In a survey of T. spiralis mRNAs, individual mRNAs were found to be trans-spliced to a number of different spliced leader sequences. These data provide the first indication that the last common ancestor of the phylum Nematoda utilized spliced leader trans-splicing and that the canonical spliced leader, SL1, found in Caenorhabditis elegans, evolved after the divergence of the major nematode clades. This discovery sheds important light on the nature and evolution of mRNA processing in the Nematoda.
The politics of symbolism: Richard Nixon's appeal to white ethnics and the frustration of realignment 196972
Authors: Merton Joe
Published: February 2008

Sensing a tangible political opportunity to bolster his and his party's minority status, Richard Nixon made an unprecedented attempt to align disaffected ethnic Americans with the Republican Party in the late 1960s and early 1970s. Nixon possessed a keen awareness of the ethnic revival
of the early 1970s and engaged with specifically ethnic issues such as parochial school aid and ethnic heritage studies, and also shaped much of his early substantive policy to appeal to ethnics, culminating in the publication of the Rosow Report on blue-collar workers in May 1970. However,
Nixon's presidential style and eventual prioritisation of symbolic or ephemeral issues, notably the appointment of ethnic Americans to government positions, over more substantive policy doomed any attempt to build a new Republican majority to failure. If white ethnic voters were to realign,
Nixon would need to offer enduring presidential policy that appealed to their ethnic and class interests, but his politics of symbolism subjugated his plans for a new Republican majority to quick-fix tactics for ensuring his re-election.
The Complexities of Perceived Risk in Cross-Cultural Services Marketing
Authors: Keh Hean Tat , Sun Jin
Published: February 2008

Previous research has found that cultural differences influence consumer risk evaluation. From a cross-national perspective, the authors explore the individual and cultural causes, as well as the consequences, of postpurchase personal and nonpersonal risks for a credence service (i.e., insurance). Using survey data from 309 Chinese consumers and 193 Singaporean consumers, the authors find that two cultural dimensions (self-transcendence/self-enhancement versus conservation/openness to change) and individual contextual factors (involvement and face consciousness) exert differential effects on consumer perceived risk in the two countries. In addition, the authors find that personal and nonpersonal risks have varying levels of impact on perceived value and customer satisfaction in the two countries.
Brand Origin Identification by Consumers: A Classification Perspective
Authors: Balabanis George , Diamantopoulos Adamantios
Published: February 2008

The authors apply a classification perspective to (1) examine the extent to which consumers can identify the correct country of origin (COO) of different brands of consumer durables, (2) investigate the factors facilitating/hindering correct COO identification, and (3) trace the implications of correct/incorrect COO identification on brand evaluation. The results from a U.K. sample indicate that consumers’ ability to classify brands correctly according to their origin is limited and also reveal substantial differences in the classification of different brands to their COO. Moreover, the key antecedent of correct COO identification is consumer ethnocentrism, with sociodemographics (e.g., age, gender) also playing a role. Finally, the authors find that though there are differences in brand evaluations depending on whether the correct COO was identified, such differences are not observed for all brands investigated.
Wie volkstümlich ist die byzantinische Volksliteratur?
Authors: Cupane Carolina
Published: February 2008

Gegenstand unserer Frage und der Überlegungen dazu ist ein Corpus von Texten, die grosso modo zwischen dem XIV. und dem XV. Jahrhundert enstanden sind, in jener Epoche also, die nach dem Namen der regierenden Dynastie auch als Palaiologenzeit bezeichnet wird. In Gegensatz zur sonstigen byzantinischen Literatur, die sich antikisierend am attischen Griechisch orientierte, sind sie in einer Sprachform verfaßt, die viele Ähnlichkeiten mit dem modernen neugriechischen Idiom aufweist. Diese neue Texte kennzeichnet bei aller inhaltlichen Vielfalt – abenteuerliche, heldenhafte, romanhafte Themen werden gleich satirischen, didaktischen und paränetischen behandelt – eine strenge formale Einheitlicheit insofern, als sie beinahe alle in dem auch für die neugriechische (Volks)dichtung charakteristischen Versmaß, dem ungereimten, von den Byzantinern selbst πολιτιϰὸς στίχος genannten Fünfzehnsilber verfaßt sind und eine mehr oder weniger starke Formelhaftigkeit in der poetischen Diktion aufweisen. Darüber hinaus runden weitere äußerliche Eigenschaften, etwa die instabile, variantenreiche und sehr spät einsetzende handschriftliche Überlieferung oder die durchgehende Anonymität der Werke, die homogene Erscheinung des volksprachlichen Literaturcorpus ab.