bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulated contact frequencies at gene-rich loci support a statistical helix model for mammalian chromatin organization
Authors: Court Franck , Miro Julie , Braem Caroline , Lelay-Taha Marie-Noëlle , Brisebarre Audrey , Atger Florian , Gostan Thierry , Weber Michaël , Cathala Guy , Forné Thierry
Published: May 2011

Background

Despite its critical role for mammalian gene regulation, the basic structural landscape of chromatin in living cells remains largely unknown within chromosomal territories below the megabase scale.

Results

Here, using the 3C-qPCR method, we investigate contact frequencies at high resolution within interphase chromatin at several mouse loci. We find that, at several gene-rich loci, contact frequencies undergo a periodical modulation (every 90 to 100 kb) that affects chromatin dynamics over large genomic distances (a few hundred kilobases). Interestingly, this modulation appears to be conserved in human cells, and bioinformatic analyses of locus-specific, long-range cis-interactions suggest that it may underlie the dynamics of a significant number of gene-rich domains in mammals, thus contributing to genome evolution. Finally, using an original model derived from polymer physics, we show that this modulation can be understood as a fundamental helix shape that chromatin tends to adopt in gene-rich domains when no significant locus-specific interaction takes place.

Conclusions

Altogether, our work unveils a fundamental aspect of chromatin dynamics in mammals and contributes to a better understanding of genome organization within chromosomal territories.
Relaxin Induces Rapid Dilation of Rodent Small Renal and Human Subcutaneous Arteries via PI3 Kinase and Nitric Oxide
Authors: McGuane Jonathan T. , Debrah Julianna E. , Sautina Laura , Jarajapu Yagna P. R. , Novak Jacqueline , Rubin J. Peter , Grant Maria B. , Segal Mark , Conrad Kirk P.
Published: May 2011

The peptide hormone relaxin is a potent vasodilator with therapeutic potential in diseases complicated by vasoconstriction, including heart failure. However, the molecular mediators and magnitude of vasodilation may vary according to duration of exposure and artery type. The objective of these studies was to determine mechanisms of rapid (within minutes) relaxin-induced vasodilation and to examine whether relaxin dilates arteries from different animal species and vascular beds. Rat and mouse small renal, rat mesenteric, and human sc arteries were isolated, mounted in a pressure arteriograph, and treated with recombinant human relaxin (rhRLX; 1–100 ng/ml) after preconstriction with phenylephrine. Rat and mouse small renal as well as human sc arteries dilated in response to rhRLX, whereas rat mesenteric arteries did not. Endothelial removal or pretreatment with l-NG-monomethyl arginine (L-NMMA) abolished rapid relaxin-induced vasodilation; phosphatidylinositol-3-kinase (PI3K) inhibitors also prevented it. In cultured human endothelial cells, rhRLX stimulated nitric oxide (assessed using 4-amino-5-methylamino-2′7′-difluorofluorescein) as well as Akt and endothelial NO synthase (eNOS) phosphorylation by Western blotting but not increases in intracellular calcium (evaluated by fura-2). NO production was attenuated by inhibition of Gαi/o and Akt (using pertussis toxin and the allosteric inhibitor MK-2206, respectively), PI3K, and NOS. Finally, the dilatory effect of rhRLX in rat small renal arteries was unexpectedly potentiated, rather than inhibited, by pretreatment with the vascular endothelial growth factor receptor inhibitor SU5416. We conclude that relaxin rapidly dilates select arteries across a range of species. The mechanism appears to involve endothelial Gαi/o protein coupling to PI3K, Akt, and eNOS but not vascular endothelial growth factor receptor transactivation or increased calcium.
Inhibition of SRY-Calmodulin Complex Formation Induces Ectopic Expression of Ovarian Cell Markers in Developing XY Gonads
Authors: Sim Helena , Argentaro Anthony , Czech Daniel P. , Bagheri-Fam Stefan , Sinclair Andrew H. , Koopman Peter , Boizet-Bonhoure Brigitte , Poulat Francis , Harley Vincent R.
Published: May 2011

The transcription factor sex-determining region of the Y chromosome (SRY) plays a key role in human sex determination, because mutations in SRY cause disorders of sex development in XY individuals. During gonadal development, Sry in pre-Sertoli cells activates Sox9 gene transcription, committing the fate of the bipotential gonad to become a testis rather than an ovary. The high-mobility group domain of human SRY contains two independent nuclear localization signals, one bound by calmodulin (CaM) and the other by importin-β. Although XY females carry SRY mutations in these nuclear localization signals that affect SRY nuclear import in transfected cells, it is not known whether these transport mechanisms are essential for gonadal development and sex determination. Here, we show that mouse Sry protein binds CaM and that a CaM antagonist reduces CaM binding, nuclear accumulation, and transcriptional activity of Sry in transfected cells. CaM antagonist treatment of cultured, sexually indifferent XY mouse fetal gonads led to reduced expression of the Sry target gene Sox9, defects in testicular cord formation, and ectopic expression of the ovarian markers Rspondin1 and forkhead box L2. These results indicate the importance of CaM for SRY nuclear import, transcriptional activity, testis differentiation, and sex determination.
Maternal Nutrient Restriction During Late Gestation and Early Postnatal Growth in Sheep Differentially Reset the Control of Energy Metabolism in the Gastric Mucosa
Authors: Sebert S. P. , Dellschaft N. S. , Chan L. L. Y. , Street H. , Henry M. , Francois C. , Sharma V. , Fainberg H. P. , Patel N. , Roda J. , Keisler D. , Budge H. , Symonds M. E.
Published: May 2011

Fetal growth restriction followed by accelerated postnatal growth contributes to impaired metabolic function in adulthood. The extent to which these outcomes may be mediated centrally within the hypothalamus, as opposed to in the periphery within the digestive tract, remains unknown. In a sheep model, we achieved intrauterine growth restriction experimentally by maternal nutrient restriction (R) that involved a 40% reduction in food intake through late gestation. R offspring were then either reared singly to accelerate postnatal growth (RA) or as twins and compared with controls also reared singly. From weaning, all offspring were maintained indoors until adulthood. A reduced litter size accelerated postnatal growth for only the first month of lactation. Independently from postnatal weight gain and later fat mass, R animals developed insulin resistance as adults. However, restricted accelerated offspring compared with both the control accelerated and restricted restricted offspring ate less and had higher fasting plasma leptin as adults, an adaptation which was accompanied by changes in energy sensing and cell proliferation within the abomasum. Additionally, although fetal restriction down-regulated gene expression of mammalian target of rapamycin and carnitine palmitoyltransferase 1-dependent pathways in the abomasum, RA offspring compensated for this by exhibiting greater activity of AMP-activated kinase-dependent pathways. This study demonstrates a role for perinatal nutrition in the peripheral control of food intake and in energy sensing in the gastric mucosal and emphasizes the importance of diet in early life in regulating energy metabolism during adulthood.
Lack of Maternal Glutamate Cysteine Ligase Modifier Subunit (Gclm) Decreases Oocyte Glutathione Concentrations and Disrupts Preimplantation Development in Mice
Authors: Nakamura Brooke N. , Fielder Thomas J. , Hoang Yvonne D. , Lim Jinhwan , McConnachie Lisa A. , Kavanagh Terrance J. , Luderer Ulrike
Published: May 2011

Glutathione (GSH) is the most abundant intracellular thiol and an important regulator of cellular redox status. Mice that lack the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in GSH synthesis, have decreased GSH synthesis. Nicotinamide nucleotide transhydrogenase, an inner mitochondrial membrane protein, catalyzes the interconversion of reduced nicotinamide adenine dinucleotide and reduced nicotinamide adenine dinucleotide phosphate; reduced nicotinamide adenine dinucleotide phosphate is required for reduction of GSH disulfide. Previous work supports roles for GSH in preimplantation development. We hypothesized that Gclm−/− mice have increased preimplantation embryonic mortality and that this effect is enhanced by absence of a functioning Nnt gene. Gclm−/− females produced significantly fewer pups per litter than Gclm+/+ littermates. Numbers of oocytes ovulated in a natural estrous cycle or upon superovulation did not differ by genotype. Fewer uterine implantation sites were observed in the Gclm−/− females. Prepubertal Gclm−/− and Gclm+/+ females were superovulated, then mated overnight with a Gclm+/+ male. At 0.5 d postcoitum, Gclm−/− females had significantly lower percentages of zygotes with two pronuclei and higher percentages of zygotes with one pronucleus than Gclm+/+ or Gclm+/− females. At 3.5 d postcoitum, a significantly lower percentage of blastocyst stage embryos was recovered from uteri of Gclm−/− females than Gclm+/+ females. Embryonic development to the blastocyst stage, but not the two-cell stage, was significantly decreased after in vitro fertilization of oocytes from Gclm−/− females compared with Gclm+/+ females. The Nnt mutation did not enhance the effects of Gclm genotype on female fertility. These results demonstrate critical roles for maternal GSH in supporting normal preimplantation development.
Interdependency of cell adhesion, force generation and extracellular proteolysis in matrix remodeling
Authors: Kirmse Robert , Otto Hannes , Ludwig Thomas
Published: May 2011

It is becoming increasingly evident that the micromechanics of cells and their environment determine cell fate and function as much as soluble molecular factors do. We hypothesized that extracellular matrix proteolysis by membrane type 1 matrix metalloproteinase (MT1-MMP) depends on adhesion, force generation and rigidity sensing of the cell. Melanoma cells (MV3 clone) stably transfected with MT1-MMP, or the empty vector as a control, served as the model system. α2β1 integrins (cell adhesion), actin and myosin II (force generation and rigidity sensing) were blocked by their corresponding inhibitors (α2β1 integrin antibodies, Cytochalasin D, blebbistatin). A novel, anisotropic matrix array of parallel, fluorescently labeled collagen-I fibrils was used. Cleavage and bundling of the collagen-I fibrils, and spreading and durotaxis of the cells on this matrix array could be readily discerned and quantified by a combined set-up for fluorescence and atomic force microscopy. In short, expression of the protease resulted in the generation of structural matrix defects, clearly indicated by gaps in the collagen lattice and loose fiber bundles. This key feature of matrix remodeling depended essentially on the functionality of α2β1 integrin, the actin filament network and myosin II motor activity. Interference with any of these negatively impacted matrix cleavage and three-dimensional matrix entanglement of cells.
Membrane potential depolarization decreases the stiffness of vascular endothelial cells
Authors: Callies Chiara , Fels Johannes , Liashkovich Ivan , Kliche Katrin , Jeggle Pia , Kusche-Vihrog Kristina , Oberleithner Hans
Published: May 2011

The stiffness of vascular endothelial cells is crucial to mechanically withstand blood flow and, at the same time, to control deformation-dependent nitric oxide release. However, the regulation of mechanical stiffness is not yet understood. There is evidence that a possible regulator is the electrical plasma membrane potential difference. Using a novel technique that combines fluorescence-based membrane potential recordings with atomic force microscopy (AFM)-based stiffness measurements, the present study shows that membrane depolarization is associated with a decrease in the stiffness of endothelial cells. Three different depolarization protocols were applied, all of which led to a similar and significant decrease in cell stiffness, independently of changes in cell volume. Moreover, experiments using the actin-destabilizing agent cytochalasin D indicated that depolarization acts by affecting the cortical actin cytoskeleton. A model is proposed whereby a change of the electrical field across the plasma membrane is directly sensed by the submembranous actin network, regulating the actin polymerization:depolymerization ratio and thus cell stiffness. This depolarization-induced decrease in the stiffness of endothelial cells could play a role in flow-mediated nitric-oxide-dependent vasodilation.
Temperature-dependent modification of muscle precursor cell behaviour is an underlying reason for lasting effects on muscle cellularity and body growth of teleost fish
Authors: Steinbacher Peter , Marschallinger Julia , Obermayer Astrid , Neuhofer Alois , Sänger Alexandra M. , Stoiber Walter
Published: May 2011

Temperature is an important factor influencing teleost muscle growth, including a lasting (‘imprinted’) influence of embryonic thermal experience throughout all further life. However, little is known about the cellular processes behind this phenomenon. The study reported here used digital morphometry and immunolabelling for Pax7, myogenin and H3P to quantitatively examine the effects of thermal history on muscle precursor cell (MPC) behaviour and muscle growth in pearlfish (Rutilus meidingeri) until the adult stage. Fish were reared at three different temperatures (8.5, 13 and 16°C) until hatching and subsequently kept under the same (ambient) thermal conditions. Cellularity data were combined with a quantitative analysis of Pax7+ MPCs including those that were mitotically active (Pax7+/H3P+) or had entered differentiation (Pax7+/myogenin+). The results demonstrate that at hatching, body lengths, fast and slow muscle cross-sectional areas and fast fibre numbers are lower in fish reared at 8.5 and 13°C than at 16°C. During the larval period, this situation changes in the 13°C-fish, so that these fish are finally the largest. The observed effects can be related to divergent cellular mechanisms at the MPC level that are initiated in the embryo during the imprinting period. Embryos of 16°C-fish have reduced MPC proliferation but increased differentiation, and thus give rise to larger hatchlings. However, their limited MPC reserves finally lead to smaller adults. By contrast, embryos of 13°C-fish and, to a lesser extent, 8.5°-fish, show enhanced MPC proliferation but reduced differentiation, thus leading to smaller hatchlings but allowing for a larger MPC pool that can be used for enhanced post-hatching growth, finally resulting in larger adults.
Minimum daily core body temperature in western grey kangaroos decreases as summer advances: a seasonal pattern, or a direct response to water, heat or energy supply?
Authors: Maloney Shane K. , Fuller Andrea , Meyer Leith C. R. , Kamerman Peter R. , Mitchell Graham , Mitchell Duncan
Published: May 2011

Using implanted temperature loggers, we measured core body temperature in nine western grey kangaroos every 5 min for 24 to 98 days in spring and summer. Body temperature was highest at night and decreased rapidly early in the morning, reaching a nadir at 10:00 h, after ambient temperature and solar radiation had begun to increase. On hotter days, the minimum morning body temperature was lower than on cooler days, decreasing from a mean of 36.2°C in the spring to 34.0°C in the summer. This effect correlated better with the time of the year than with proximate thermal stressors, suggesting that either season itself or some factor correlated with season, such as food availability, caused the change. Water saving has been proposed as a selective advantage of heterothermy in other large mammals, but in kangaroos the water savings would have been small and not required in a reserve with permanent standing water. We calculate that the lower core temperature could provide energy savings of nearly 7%. It is likely that the heterothermy that we observed on hot days results either from decreased energy intake during the dry season or from a seasonal pattern entrained in the kangaroos that presumably has been selected for because of decreased energy availability during the dry season.
The hydrodynamic disturbances of two species of krill: implications for aggregation structure
Authors: Catton Kimberly B. , Webster Donald R. , Kawaguchi So , Yen Jeannette
Published: May 2011

Krill aggregations vary in size, krill density and uniformity depending on the species of krill. These aggregations may be structured to allow individuals to sense the hydrodynamic cues of neighboring krill or to avoid the flow fields of neighboring krill, which may increase drag forces on an individual krill. To determine the strength and location of the flow disturbance generated by krill, we used infrared particle image velocimetry measurements to analyze the flow field of free-swimming solitary specimens (Euphausia superba and Euphausia pacifica) and small, coordinated groups of three to six E. superba. Euphausia pacifica individuals possessed shorter body lengths, steeper body orientations relative to horizontal, slower swimming speeds and faster pleopod beat frequencies compared with E. superba. The downward-directed flow produced by E. pacifica has a smaller maximum velocity and smaller horizontal extent of the flow pattern compared with the flow produced by E. superba, which suggests that the flow disturbance is less persistent as a potential hydrodynamic cue for E. pacifica. Time record analysis reveals that the hydrodynamic disturbance is very weak beyond two body lengths for E. pacifica, whereas the hydrodynamic disturbance is observable above background level at four body lengths for E. superba. Because the nearest neighbor separation distance of E. superba within a school is less than two body lengths, hydrodynamic disturbances are a viable cue for intraspecies communication. The orientation of the position of the nearest neighbor is not coincident with the orientation of the flow disturbance, however, which indicates that E. superba are avoiding the region of strongest flow.
What causes wing wear in foraging bumble bees?
Authors: Foster Danusha J. , Cartar Ralph V.
Published: May 2011

Flying is an ecologically important behaviour in many insects, but it often results in permanent wing damage. Although wing wear in insects is often used as a method to determine insect age, and is associated with an increased risk of mortality, the causes of wing wear are unresolved. In this paper, we examine whether wing use while foraging explains wing wear in bumble bees (Bombus spp.). Wing wear may result from three distinct flight characteristics during foraging: time spent in flight, flight frequency and frequency of wing collisions with vegetation. To test these hypotheses for causes of wing wear, we recorded digital video of individually marked bumble bees foraging in nature on 12 different plant species that result in variation in these flight characteristics, and recaptured these individuals to photograph their wings over time. Bumble bees with a higher frequency of wing collisions showed an increased loss of wing area, which became more severe over time. Neither time in flight nor flight frequency was uniquely and significantly associated with wing wear. Therefore, the collision frequency hypothesis best explained wing wear in bumble bees. We conclude that wing use during foraging in bumble bees results in wing wear. Wing wear reflects behaviour, not simply age. Because wing wear has elsewhere been shown to increase mortality, this study provides an important mechanism linking foraging behaviour with lifespan.
What triggers the aerobic dive limit? Patterns of muscle oxygen depletion during dives of emperor penguins
Authors: Williams Cassondra L. , Meir Jessica U. , Ponganis Paul J.
Published: May 2011

The physiological basis of the aerobic dive limit (ADL), the dive duration associated with the onset of post-dive blood lactate elevation, is hypothesized to be depletion of the muscle oxygen (O2) store. A dual wavelength near-infrared spectrophotometer was developed and used to measure myoglobin (Mb) O2 saturation levels in the locomotory muscle during dives of emperor penguins (Aptenodytes forsteri). Two distinct patterns of muscle O2 depletion were observed. Type A dives had a monotonic decline, and, in dives near the ADL, the muscle O2 store was almost completely depleted. This pattern of Mb desaturation was consistent with lack of muscle blood flow and supports the hypothesis that the onset of post-dive blood lactate accumulation is secondary to muscle O2 depletion during dives. The mean type A Mb desaturation rate allowed for calculation of a mean muscle O2 consumption of 12.4 ml O2 kg–1 muscle min–1, based on a Mb concentration of 6.4 g 100 g–1 muscle. Type B desaturation patterns demonstrated a more gradual decline, often reaching a mid-dive plateau in Mb desaturation. This mid-dive plateau suggests maintenance of some muscle perfusion during these dives. At the end of type B dives, Mb desaturation rate increased and, in dives beyond the ADL, Mb saturation often reached near 0%. Thus, although different physiological strategies may be used during emperor penguin diving, both Mb desaturation patterns support the hypothesis that the onset of post-dive lactate accumulation is secondary to muscle O2 store depletion.
Post-prandial changes in protein synthesis in red drum (Sciaenops ocellatus) larvae
Authors: McCarthy Ian D. , Fuiman Lee A.
Published: May 2011

Protein synthesis is one of the major energy-consuming processes in all living organisms. Post-prandial changes in protein synthesis have been studied in a range of animal taxa but have been little studied in fish larvae. Using the flooding-dose method, we measured post-prandial changes in whole-body rates of protein synthesis in regularly fed red drum Sciaenops ocellatus (Linnaeus) larvae for 24–28 h following their daily meal. Fractional rates of protein synthesis increased from a baseline (pre-feeding) rate of 16% day–1 to a post-prandial peak of 48% day–1 ca. 8 h after feeding before declining to 12% day–1 after 24–28 h. The overall mean daily rate of protein synthesis was calculated as 27% day–1. Although suggested as energetically impossible in larval poikilotherms, our results show that rates in excess of 30% day–1 can be attained by larval fishes for a few hours but are not sustained. The average daily energetic cost of protein synthesis was estimated as 34% of daily total oxygen consumption, ranging from 19% immediately before feeding to 61% during the post-prandial peak in protein synthesis. This suggests that during the post-prandial peak, protein synthesis will require a large proportion of the hourly energy production, which, given the limited metabolic scope in fish larvae, may limit the energy that could otherwise be allocated to other energy-costly functions, such as foraging and escape responses.
Tarantulas cling to smooth vertical surfaces by secreting silk from their feet
Authors: Rind F. Claire , Birkett Chris Luke , Duncan Benjamin-James A. , Ranken Alexander J.
Published: May 2011

Like all spiders, tarantulas (family Theraphosidae) synthesize silk in specialized glands and extrude it from spinnerets on their abdomen. In one species of large tarantula, Aphonopelma seemanni, it has been suggested that silk can also be secreted from the tarsi but this claim was later refuted. We provide evidence of silk secretion directly from spigots (nozzles) on the tarsi of three distantly related tarantula species: the Chilean rose, Grammostola rosea; the Indian ornamental, Poecilotheria regalis; and the Mexican flame knee, Brachypelma auratum, suggesting tarsal silk secretion is widespread among tarantulas. We demonstrate that multiple strands of silk are produced as a footprint when the spider begins to slip down a smooth vertical surface. The nozzle-like setae on the tarsi responsible for silk deposition have shanks reinforced by cuticular thickenings, which serve to prevent the shanks' internal collapse while still maintaining their flexibility. This is important as the spigots occur on the ventral surface of the tarsus, projecting beyond the finely divided setae of the dry attachment pads. We also reveal the structure and disposition of the silk-secreting spigots on the abdominal spinnerets of the three tarantula species and find they are very similar to those from the earliest known proto-spider spinneret from the Devonian period, giving another indication that silk secretion in tarantulas is close to the ancestral condition.
Photoalignment and Photoinduced Molecular Reorientation of Photosensitive Materials
Authors: Kawatsuki Nobuhiro
Published: May 2011

Photosensitive materials for photoalignment of liquid crystals (LCs) and photoinduced molecular reorientation are described, especially focusing on azobenzene-containing materials and photocrosslinkable polymers. All the materials generate photoinduced optical anisotropy by means of linearly polarized (LP) light exposure. The large optical anisotropy is induced when the axis-selective photoreaction is accompanied by molecular reorientation.
Synthesis of a Chiral-structured Molecular Magnet Based on a Cyano-bridged Co–W Bimetal Assembly
Authors: Komori Orisaku Keiko , Nakabayashi Koji , Ohkoshi Shin-ichi
Published: May 2011

A three-dimensional chiral-structured molecular magnet based on a Co–W bimetal assembly, [CoII(H2O)2][CoII(pyrimidine){(R)-1-(4-pyridyl)ethanol)}]2[WV(CN)8]2·7.5H2O, is synthesized. This compound exhibits a spontaneous magnetization due to ferromagnetic ordering between CoII (S = 3/2) and WV (S = 1/2) with a Curie temperature of 19 K and coercive field of 3600 Oe.
A Biomimetic Approach for Creating Thermally Stable Polyimide-coated Honeycomb Films
Authors: Yabu Hiroshi , Nakamichi Yuki , Hirai Yuji , Shimomura Masatsugu
Published: May 2011

In this paper, we show a simple biomimetic approach for fabricating thermally stable porous films with multilayered structures by mimicking beetle wings. Honeycomb-patterned porous films (honeycomb films) of poly(1,2-butadiene) (PB) were successfully prepared by casting chloroform solution of PB and amphiphilic polymer under humid conditions. After formation of layer-by-layer (LbL) film of poly(amic acid) (PAA), which is a precursor of polyimide, and poly(allylamine hydrochloride) (PAH) onto the surface of PB honeycomb films, PAA was successfully converted to polyimide by chemical imidization. After imidization, the LbL-coated honeycomb films have high thermal stability.
Telaprevir: An NS3/4A Protease Inhibitor for the Treatment of Chronic Hepatitis C
Authors: Smith Lisa S , Nelson Michael , Naik Sagar , Woten Joanna
Published: May 2011

Objective:

To review the use of telaprevir for the treatment of chronic hepatitis C.

Data Sources:

Clinical studies were identified through MEDLINE (1966-January 2011), bibliographies of articles, clinicaltrials.gov, and fda.gov, using key words VX-950, telaprevir, and chronic hepatitis C.

Study Selection and Data Extraction:

Phase 1, 2, and 3 human and animal studies describing the pharmacology, pharmacokinetics, efficacy, and safety of telaprevir were identified. Additional articles were identified from the bibliographies of articles retrieved through MEDLINE.

Data Synthesis:

Telaprevir is an NS3/4A protease inhibitor under investigation for the treatment of chronic hepatitis C virus (HCV) with pegylated interferon and ribavirin. Telaprevir competes with viral peptide substrates for the active site of NS3 and inhibits NS3-NS4A protease activity. Telaprevir has activity against HCV genotype 1 infection in vitro and in vivo, but monotherapy results in rapid viral resistance. In 3 Phase 2 and 3 Phase 3 randomized placebo-controlled trials, 12 weeks of telaprevir, along with varying durations of ribavirin treatment, induced higher sustained virologic response (SVR) compared with ribavirin alone. SVR was approximately 70% in treatment-naïve patients, 50-60% for patients in whom SVR had not occurred with prior ribavirin treatment, and 40-45% of those who received ribavirin alone. There was a high incidence of maculopapular rash (52% in 1 trial) and anemia (27% in 1 trial) in telaprevir-treated patients. The average dropout rate in Phase 3 trials as a result of adverse effects was 13%.

Conclusions:

Twelve weeks of telaprevir with concomitant ribavirin treatment increases SVR for treatment-naïve and non-naïve patients with genotype 1 chronic HCV compared to 48 weeks of ribavirin treatment. Telaprevir may shorten the length of ribavirin therapy for some patients with extended rapid viral response, but viral mutations, adverse effects, and a high dropout rate may reduce the SVR seen in clinical practice.
Diabetes and Cardiovascular Disease Interventions by Community Pharmacists: A Systematic Review
Authors: Evans Charity D , Watson Erin , Eurich Dean T , Taylor Jeff G , Yakiwchuk Erin M , Shevchuk Yvonne M , Remillard Alfred , Blackburn David
Published: May 2011

Objective:

To systematically review and assess the quality of studies evaluating community pharmacist interventions for preventing or managing diabetes or cardiovascular disease (CVD) and/or their major risk factors.

Data Sources:

A comprehensive literature search was performed using MEDLINE (1950-February 2011), EMBASE (1980-February 2011), International Pharmaceutical Abstracts (1970-February 2011), Cumulative Index to Nursing and Allied Health Literature (1982-June 2007), and Cochrane Central Register of Controlled Trials (1898-February 2011). Search terms included: community pharmacy(ies), community pharmacist(s), cardiovascular, diabetes, and intervention. The grey literature was searched using the ProQuest Dissertations and Theses, Theses Canada, and OAlster databases.

Study Selection and Data Extraction:

Articles published in English or French with all study designs were considered for the review. Studies were included if they contained interventions designed to reduce the incidence, risk, or mortality of CVD or diabetes; affect clinical indicators of CVD or diabetes mellitus (including hypertension, dyslipidemia, or hemoglobin A1c); and/or improve adherence to treatment strategies. Only studies involving interventions carried out primarily by pharmacists in community pharmacy settings were included. Study quality was assessed using a checklist validated for both randomized and nonrandomized studies.

Data Synthesis:

A total of 4142 studies were initially identified, with 40 meeting our inclusion criteria. Eleven studies were randomized controlled trials, 4 were cluster randomized trials, and 2 studies had randomized before-after designs. The remaining studies were controlled before-after (n = 2), cohort (n = 4), and uncontrolled before-after (n = 17) designs. Interventions focused on diabetes (n = 12), hypertension (n = 9), medication adherence (n = 9), lipids (n = 5), evidence-based medication initiation or optimization (n = 3), risk factor prediction scores (n = 1), and body mass index (n = 1). All studies contained interventions focused at the patient level and the majority of studies (34/40) involved interventions directed at both the physician and patient. No specific intervention emerged as superior, and study quality was generally poor, making it difficult to determine the true effect of the interventions.

Conclusions:

Poor study quality, time-intensive interventions, and unproven clinical significance warrant the need for further high-quality studies of community pharmacist interventions for preventing or managing diabetes or CVD and/or their major risk factors.
Coiled coils as possible models of protein structure evolution
Authors: Gáspári Zoltán , Nyitray László
Published: May 2011

Coiled coils are formed by two or more α-helices wrapped around one another. This structural motif often guides di-, tri- or multimerization of proteins involved in diverse biological processes such as membrane fusion, signal transduction and the organization of the cytoskeleton. Although coiled coil motifs seem conceptually simple and their existence was proposed in the early 1950s, the high variability of the motif makes coiled coil prediction from sequence a difficult task. They might be confused with intrinsically disordered sequences and even more with a recently described structural motif, the charged single α-helix. By contrast, the versatility of coiled coil structures renders them an ideal candidate for protein (re)design and many novel variants have been successfully created to date. In this paper, we review coiled coils in the light of protein evolution by putting our present understanding of the motif and its variants in the context of structural interconversions. We argue that coiled coils are ideal subjects for studies of subtle and large-scale structural changes because of their well-characterized and versatile nature.
Effect of apolipoprotein E polymorphism on statin-induced decreases in plasma lipids and cardiovascular events
Authors: Hubacek Jaroslav A. , Vrablik Michal
Published: May 2011

Hypercholesterolemia or dyslipidemia is an independent risk factor for cardiovascular disease and statins (inhibitors of a key enzyme of cholesterol synthesis, 3-hydroxymethyl glutaryl coenzyme A reductase) are the drugs of choice for decreasing plasma cholesterol. It has been estimated that genetic factors can explain 40%–60% of final cholesterol concentrations and approximately 70% of the efficacy of statin treatment. The gene most often analyzed in the context of statin efficacy is the gene for apolipoprotein E (APOE). This review summarizes evidence of the association between variations in theAPOEgene locus and the response of plasma lipids to statin therapy. Although the results are not consistent, carriers of theAPOE4allele seems to be less responsive to statins than carriers ofAPOE2andAPOE3alleles. This effect is partially context-dependent (gene-gender interactions; gene-nutrition and gene-smoking interactions have not yet been studied) and the absolute differences vary between different population groups.
Impaired GABA and Glycine Transmission Triggers Cardinal Features of Rapid Eye Movement Sleep Behavior Disorder in Mice
Authors: Brooks Patricia L. , Peever John H.
Published: May 2011

Rapid eye movement (REM) sleep behavior disorder (RBD) is a neurological disease characterized by loss of normal REM motor inhibition and subsequent dream enactment. RBD is clinically relevant because it predicts neurodegenerative disease onset (e.g., Parkinson's disease) and is clinically problematic because it disrupts sleep and results in patient injuries and hospitalization. Even though the cause of RBD is unknown, multiple lines of evidence indicate that abnormal inhibitory transmission underlies the disorder. Here, we show that transgenic mice with deficient glycine and GABA transmission have a behavioral, motor, and sleep phenotype that recapitulates the cardinal features of RBD. Specifically, we show that mice with impaired glycine and GABAAreceptor function exhibit REM motor behaviors, non-REM muscle twitches, sleep disruption, and EEG slowing—the defining disease features. Importantly, the RBD phenotype is rescued by drugs (e.g., clonazepam and melatonin) that are routinely used to treat human disease symptoms. Our findings are the first to identify a potential mechanism for RBD—we show that deficits in glycine- and GABAA-mediated inhibition trigger the full spectrum of RBD symptoms. We propose that these mice are a useful resource for investigatingin vivodisease mechanisms and developing potential therapeutics for RBD.
Neuronal Nitric Oxide Contributes to Neuroplasticity-Associated Protein Expression through cGMP, Protein Kinase G, and Extracellular Signal-Regulated Kinase
Authors: Gallo Eduardo F. , Iadecola Costantino
Published: May 2011

Nitric oxide (NO) synthesized by neuronal NO synthase (nNOS) has long been implicated in brain plasticity. However, it is unclear how this short-lived mediator contributes to the long-term molecular changes underlying neuroplasticity, which typically require activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) signaling pathway and gene expression. To address this issue, we used a neuroplasticity model based on treatment of neuronal cultures with bicuculline and a model of experience-dependent plasticity in the barrel cortex. In neuronal cultures, NOS inhibition attenuated the bicuculline-induced activation of ERK and the expression of c-Fos, Egr-1, Arc, and brain-derived neurotrophic factor (BDNF), proteins essential for neuroplasticity. Furthermore, inhibition of the NO target soluble guanylyl cyclase or of the cGMP effector kinase protein kinase G (PKG) reduced both ERK activation and plasticity-related protein expression. NOS inhibition did not affect phosphorylation of cAMP response element-binding protein (CREB), a well-established ERK nuclear target, but it attenuated the nuclear accumulation of the CREB coactivator TORC1 and suppressed the activation of Elk-1, another transcription factor target of ERK. Consistent with thesein vitroobservations, induction of c-Fos, Egr-1, and BDNF was attenuated in the D1 cortical barrel ofnNOS−/−mice subjected to single whisker experience. These results establish nNOS-derived NO as a key factor in the expression of proteins involved in neuroplasticity, an effect mediated through cGMP, PKG, and ERK signaling. These actions of NO do not depend on CREB phosphorylation but may involve TORC1 and Elk-1. Our data unveil a previously unrecognized link between neuronal NO and the molecular machinery responsible for the sustained synaptic changes underlying neuroplasticity.
Nerve Growth Factor Contribution via Transient Receptor Potential Vanilloid 1 to Ectopic Orofacial Pain
Authors: Shinoda Masamichi , Asano Masatake , Omagari Daisuke , Honda Kuniya , Hitomi Suzuro , Katagiri Ayano , Iwata Koichi
Published: May 2011

It is well known that oral inflammation causes tenderness in temporomandibular joints or masseter muscles. The exact mechanism of such an orofacial ectopic hyperalgesia remains unclear. Here, we investigated the functional significance of interaction of nerve growth factor (NGF) and transient receptor potential vanilloid 1 (TRPV1) in relation to heat hyperalgesia in the whisker pad skin caused by complete Freund's adjuvant (CFA) injection into the lower lip. CFA injection induced heat hyperalgesia of the ipsilateral whisker pad skin. Moreover, it leads to enhancement of spontaneous activity and heat responses in trigeminal ganglion (TG) neurons that was elicited by heat stimulation of the whisker pad skin. The heat hyperalgesia was dose-dependently reversed by intraperitoneal TRPV1 antagonist administration, also diminished by neutralizing anti-NGF antibody administration into the lower lip and intraganglionic administration of K252a, a tyrosine kinase receptor inhibitor. Nerve fibers in bundle of mandibular nerve and TG neurons that innervates the whisker pad skin and lower lip both expressed labeled NGF, which was administrated into the lower lip. Moreover, the NGF concentrations in ophthalmic-maxillary and mandibular divisions of the TG increased after CFA injection into the lower lip. The number of TRPV1-positive neurons that innervates the whisker pad skin and lower lip was increased after CFA injection into the lower lip, and this increase was annulled by anti-NGF administration. The present findings suggest that inflammation in the lower lip induces release of NGF that regulates TRPV1 expression in TG neurons. This TRPV1 overexpression may underlie ectopic heat hyperalgesia in the whisker pad skin.
AKAP79/150 Signal Complexes in G-Protein Modulation of Neuronal Ion Channels
Authors: Zhang Jie , Bal Manjot , Bierbower Sonya , Zaika Oleg , Shapiro Mark S.
Published: May 2011

Voltage-gated M-type (KCNQ) K+channels play critical roles in regulation of neuronal excitability. Previous work showed A-kinase-anchoring protein (AKAP)79/150-mediated protein kinase C (PKC) phosphorylation of M channels to be involved in M current (IM) suppression by muscarinic M1, but not bradykinin B2, receptors. In this study, we first explored whether purinergic and angiotensin suppression ofIMin superior cervical ganglion (SCG) sympathetic neurons involves AKAP79/150. Transfection into rat SCG neurons of ΔA-AKAP79, which lacks the A domain necessary for PKC binding, or the absence of AKAP150 inAKAP150−/−mice, did not affectIMsuppression by purinergic agonist or by bradykinin, but reducedIMsuppression by muscarinic agonist and angiotensin II. Transfection of AKAP79, but not ΔA-AKAP79 or AKAP15, rescued suppression ofIMby muscarinic receptors inAKAP150−/−neurons. We also tested association of AKAP79 with M1, B2, P2Y6, and AT1receptors, and KCNQ2 and KCNQ3 channels, via Förster resonance energy transfer (FRET) on Chinese hamster ovary cells under total internal refection fluorescence microscopy, which revealed substantial FRET between AKAP79 and M1or AT1receptors, and with the channels, but only weak FRET with P2Y6or B2receptors. The involvement of AKAP79/150 in Gq/11-coupled muscarinic regulation of N- and L-type Ca2+channels and by cAMP/protein kinase A was also studied. We found AKAP79/150 to not play a role in the former, but to be necessary for forskolin-induced upregulation of L-current. Thus, AKAP79/150 action correlates with the PIP2(phosphatidylinositol 4,5-bisphosphate)-depletion mode ofIMsuppression, but does not generalize to Gq/11-mediated inhibition of N- or L-type Ca2+channels.
Stages of Nonsymbolic Number Processing in Occipitoparietal Cortex Disentangled by fMRI Adaptation
Authors: Roggeman Chantal , Santens Seppe , Fias Wim , Verguts Tom
Published: May 2011

The neurobiological mechanisms of nonsymbolic number processing in humans are still unclear. Computational modeling proposed three successive stages: first, the spatial location of objects is stored in an object location map; second, this information is transformed into a numerical summation code; third, this summation code is transformed to a number-selective code. Here, we used fMRI-adaptation to identify these three stages and their relative anatomical location. By presenting the same number of dots on the same locations in the visual field, we adapted neurons of human volunteers. Occasionally, deviants with the same number of dots at different locations or different numbers of dots at the same location were shown. By orthogonal number and location factors in the deviants, we were able to calculate three independent contrasts, each sensitive to one of the stages. We found an occipitoparietal gradient for nonsymbolic number processing: the activation of the object location map was found in the inferior occipital gyrus. The summation coding map exhibited a nonlinear pattern of activation, with first increasing and then decreasing activation, and most activity in the middle occipital gyrus. Finally, the number-selective code became more pronounced in the superior parietal lobe. In summary, we disentangled the three stages of nonsymbolic number processing predicted by computational modeling and demonstrated that they constitute a pathway along the occipitoparietal processing stream.
Cellular Morphine Tolerance Produced by βArrestin-2-Dependent Impairment of μ-Opioid Receptor Resensitization
Authors: Dang Vu C. , Chieng Billy , Azriel Yael , Christie MacDonald J.
Published: May 2011

Chronic morphine treatment produces behavioral and cellular opioid tolerance that has been proposed to be caused by attenuated μ-opioid receptor (MOR) recovery from desensitization (resensitization). The process of MOR resensitization is thought to require βarrestin-2 (βarr-2)-dependent trafficking of desensitized receptors to endosomal compartments, followed by recycling of resensitized receptors back to the plasma membrane. However, there is little direct evidence for this, particularly in native neurons. This study used whole-cell patch-clamp recording in locus ceruleus (LC) neurons from wild-type (w.t.) and βarr-2 knock-out (k.o.) mice to examine whether βarr-2/dynamin-dependent trafficking is required for MOR resensitization in neurons from opioid-naive and morphine-treated mice. Surprisingly, recovery of MOR from acute desensitization in LC neurons does not require βarr-2- or dynamin-dependent trafficking. To the contrary, MOR resensitization was accelerated by disruption of either βarr-2 or dynamin function. Chronic morphine treatment caused cellular MOR tolerance and concurrently impaired MOR resensitization in neurons from w.t. mice, as expected from previous studies, but neither occurred in neurons from βarr-2 k.o. mice. Moreover, the impairment of MOR resensitization caused by chronic morphine was reversed in w.t. neurons when G-protein-coupled receptor kinase-2 (GRK2) or dynamin function was disrupted. Together, these results establish that βarr-2/dynamin-dependent receptor regulation is not required for MOR resensitization in LC neurons. Furthermore, chronic morphine treatment modifies GRK2–βarr-2–dynamin-dependent MOR trafficking to impair receptor resensitization, thereby contributing to opioid tolerance in LC neurons by reducing the number of functional receptors on the surface membrane.
The Endogenous Cannabinoid 2-Arachidonoylglycerol Is Intravenously Self-Administered by Squirrel Monkeys
Authors: Justinová Zuzana , Yasar Sevil , Redhi Godfrey H. , Goldberg Steven R.
Published: May 2011

Two endogenous ligands for cannabinoid CB1receptors, anandamide (N-arachidonoylethanolamine) and 2-arachidonoylglycerol (2-AG), have been identified and characterized. 2-AG is the most prevalent endogenous cannabinoid ligand in the brain, and electrophysiological studies suggest 2-AG, rather than anandamide, is the true natural ligand for cannabinoid receptors and the key endocannabinoid involved in retrograde signaling in the brain. Here, we evaluated intravenously administered 2-AG for reinforcing effects in nonhuman primates. Squirrel monkeys that previously self-administered anandamide or nicotine under a fixed-ratio schedule with a 60 s timeout after each injection had their self-administration behavior extinguished by vehicle substitution and were then given the opportunity to self-administer 2-AG. Intravenous 2-AG was a very effective reinforcer of drug-taking behavior, maintaining higher numbers of self-administered injections per session and higher rates of responding than vehicle across a wide range of doses. To assess involvement of CB1receptors in the reinforcing effects of 2-AG, we pretreated monkeys with the cannabinoid CB1receptor inverse agonist/antagonist rimonabant [N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide]. Rimonabant produced persistent blockade of 2-AG self-administration without affecting responding maintained by food under similar conditions. Thus, 2-AG was actively self-administered by monkeys with or without a history of cannabinoid self-administration, and the reinforcing effects of 2-AG were mediated by CB1receptors. Self-administration of 2-AG by squirrel monkeys provides a valuable procedure for studying abuse liability of medications that interfere with 2-AG signaling within the brain and for investigating mechanisms involved in the reinforcing effects of endocannabinoids.