bluuebunny/crossref_metadata_2025 huggingface dataset:
SPATIAL SCALE OF LOCAL BREEDING HABITAT QUALITY AND ADJUSTMENT OF BREEDING DECISIONS
Authors: Doligez Blandine , Berthouly Anne , Doligez Damien , Tanner Marion , Saladin Verena , Bonfils Danielle , Richner Heinz
Published: May 2008

Experimental studies provide evidence that, in spatially and temporally heterogeneous environments, individuals track variation in breeding habitat quality to adjust breeding decisions to local conditions. However, most experiments consider environmental variation at one spatial scale only, while the ability to detect the influence of a factor depends on the scale of analysis. We show that different breeding decisions by adults are based on information about habitat quality at different spatial scales. We manipulated (increased or decreased) local breeding habitat quality through food availability and parasite prevalence at a small (territory) and a large (patch) scale simultaneously in a wild population of Great Tits (Parus major). Females laid earlier in high‐quality large‐scale patches, but laying date did not depend on small‐scale territory quality. Conversely, offspring sex ratio was higher (i.e., biased toward males) in high‐quality, small‐scale territories but did not depend on large‐scale patch quality. Clutch size and territory occupancy probability did not depend on our experimental manipulation of habitat quality, but territories located at the edge of patches were more likely to be occupied than central territories. These results suggest that integrating different decisions taken by breeders according to environmental variation at different spatial scales is required to understand patterns of breeding strategy adjustment.
STATISTICAL ANALYSIS OF MULTIDIMENSIONAL FUZZY SET ORDINATIONS
Authors: Roberts David W.
Published: May 2008

A protocol for the creation and statistical analysis of multidimensional fuzzy set ordinations (MFSO) is presented, including a simple forward stepwise variable selection algorithm and goodness‐of‐fit statistics. Mapping sample point distributions from the fuzzy topological space of fuzzy set ordination (FSO) to a Euclidean space enables analysis by a broad range of parametric statistical methods. The results obtained exhibit immediate interpretability, as each axis in an MFSO represents a single environmental variable and is orthogonal to all other axes by design. MFSO is tested on five data sets: three simulated coenospaces, and vegetation data from Bryce Canyon National Park, Utah, USA, and the Shoshone National Forest, Wyoming, USA. The resulting ordinations on the test data sets achieve (1) high efficiency in representing the underlying dissimilarity matrix in low dimensionality (>90% of the efficiency of principal coordinates analysis); (2) a high level of fidelity in reconstructing the location and configuration of samples in the simulated coenospaces; (3) a high level of resistance to noise in vegetation or environment data; and (4) a low level of sensitivity to sample size or placement along simulated environmental gradients. Environmental variable effect sizes are easily estimated, and probabilities of observing the results obtained are easily calculated by parametric distributions or permutation statistics.
SEX AND LIFE‐HISTORY STAGE ALTER HERBIVORE RESPONSES TO A CHEMICALLY DEFENDED RED ALGA
Authors: Vergés Adriana , Paul Nicholas A. , Steinberg Peter D.
Published: May 2008

Intraspecific variation in resistance to herbivory among genders and life‐history phases of primary producers can significantly alter the ecological and evolutionary consequences of plant–herbivore interactions. Seaweeds (macroalgae) with complex life histories have multiple distinct phases with associated variation in traits that can potentially lead to differences in resistance to consumers and provide a unique system in which to simultaneously test the effects of sex and life‐history stage on herbivory. We tested the susceptibility to grazing of the three life‐history stages and separate sexes of the chemically defended red alga Asparagopsis armata against the sea hare Aplysia parvula, and we related this to the plant quality traits of different stages and genders. Differences in nutrient content and halogenated secondary metabolites between life‐history phases were highly sex dependent. Male gametophytes had a low concentration of secondary metabolites and the highest nutrient content. The highest secondary metabolite content was found within the female gametophyte, in the wall of the reproductive structures (cystocarps) that contain the microscopic carposporophyte phase. Feeding choices by A. parvula were consistent with differences in algal quality and defense and resulted in the haploid male gametophytes being the most preferred food type. The diploid carposporophyte found inside the chemically rich cystocarps was the least consumed life‐history stage. Selective herbivory of male gametophytes by A. parvula is consistent with an observed shift in gametophyte sex ratio in the field from unity at the beginning of the reproductive season to female bias at the end. The variation in susceptibility to herbivory found between sex and life‐history stages of A. armata represents the first example of sex‐biased consumption in seaweeds and may contribute to the maintenance of complex life histories such as those found in red algae.
INTERHEMISPHERIC COMPARISON OF RECRUITMENT TO INTERTIDAL COMMUNITIES: PATTERN PERSISTENCE AND SCALES OF VARIATION
Authors: Navarrete Sergio A. , Broitman Bernardo R. , Menge Bruce A.
Published: May 2008

Recruitment variation can be a major source of fluctuation in populations and communities, making it difficult to generalize results. Determining the scales of variation and whether spatial patterns in the supply of individuals are persistent over time can provide insight into spatial generality and the application of conservation and metacommunity models. We examined these issues using eight‐year‐long data sets of monthly recruitment of intertidal mussels (Mytilus spp., Perumytilus purpuratus, Semimytilus algosus, Brachidontes granulata) and barnacles (Balanus glandula, Chthamalus dalli, Jehlius cirratus, Notochthamalus scabrosus) at sites spanning >900 km along the coasts of Oregon–northern California (OR–NCA, 45.47–39.43° N) and central Chile (CC, 29.5–34.65° S). We evaluated four general “null” hypotheses: that despite different phylogenies and great spatial separation of these taxa, their similar life history strategies and environmental settings lead to similar patterns of recruitment (1) between hemispheres, (2) in time, (3) in space, and (4) at larger and smaller spatial scales. Hypothesis 1 was rejected: along the OR–NCA coast, rates of recruitment were between two and three orders of magnitude higher, and patterns of seasonality were generally stronger and more coherent across space and time than along CC. Surprisingly, however, further analysis revealed regularities in both time and space for all species, supporting hypotheses 2 and 3. Temporal decorrelation scales were 1–3 months, and characteristic spatial scales of recruitment were ∼250 km. Contrary to hypothesis 4, for the ecologically dominant species in both hemispheres, recruitment was remarkably persistent at larger mesoscales (kilometers) but was highly stochastic at smaller microscales (meters). Across species, increased recruitment variation at large scales was positively associated with increased persistence. Our results have several implications. Although the two regions span distinct latitudinal ranges, potential forcing processes behind these patterns include similar large‐scale climates and topographically locked hydrographic features, such as upwelling. Further, spatial persistence of the recruitment patterns of most species at the mesoscale supports the view that marine protected areas can be powerful conservation and management tools. Finally, persistent and yet contrasting spatial patterns of recruitment among competing species suggest that recent metacommunity models might provide useful representations of the mechanisms involved in species coexistence.
SCALE‐DEPENDENT CHANGES IN THE IMPORTANCE OF LARVAL SUPPLY AND HABITAT TO ABUNDANCE OF A REEF FISH
Authors: White J. Wilson , Caselle Jennifer E.
Published: May 2008

While there is great interest in the degree to which local interactions “scale‐up” to predict regional patterns of abundance, few studies in marine systems have simultaneously examined patterns of abundance at both the large scale (tens of kilometers) typical of larval movement and the small scale (meters) typical of post‐settlement interactions. We addressed this gap by monitoring larval supply, adult survivorship, and giant kelp (Macrocystis pyrifera, a primary habitat‐forming species) abundance for 13 populations of kelp bass (Paralabrax clathratus) spread over ∼200 km in the Santa Barbara Channel, California, USA. At the small, within‐site scale, both recruitment and adult survivorship of kelp bass were density‐dependent and positively related to kelp abundance. At the larger, among‐site scale, the spatial pattern of adult kelp bass abundance was predicted well by the pattern of kelp bass larval supply, but there was a consistent negative spatial relationship between kelp abundance and kelp bass larval supply despite the positive effects of kelp on kelp bass at the smaller spatial scale. This large‐scale negative relationship was likely a product of a channel‐wide spatial mismatch between oceanographic conditions that favor kelp survival and those that concentrate and distribute fish larvae. These results generally support the recruit–adult hypothesis: kelp bass populations are limited by recruitment at low recruit densities but by density‐dependent competition for food resources and/or predator refuges at high recruit densities. At the same time, spatial variation in kelp abundance produced substantial spatiotemporal heterogeneity in kelp bass demographics, which argues for a multispecies, metacommunity approach to predicting kelp bass dynamics.
CONTINUOUS‐TIME CORRELATED RANDOM WALK MODEL FOR ANIMAL TELEMETRY DATA
Authors: Johnson Devin S. , London Joshua M. , Lea Mary-Anne , Durban John W.
Published: May 2008

We propose a continuous‐time version of the correlated random walk model for animal telemetry data. The continuous‐time formulation allows data that have been nonuniformly collected over time to be modeled without subsampling, interpolation, or aggregation to obtain a set of locations uniformly spaced in time. The model is derived from a continuous‐time Ornstein‐Uhlenbeck velocity process that is integrated to form a location process. The continuous‐time model was placed into a state–space framework to allow parameter estimation and location predictions from observed animal locations. Two previously unpublished marine mammal telemetry data sets were analyzed to illustrate use of the model, by‐products available from the analysis, and different modifications which are possible. A harbor seal data set was analyzed with a model that incorporates the proportion of each hour spent on land. Also, a northern fur seal pup data set was analyzed with a random drift component to account for directed travel and ocean currents.
ANTIPREDATOR DEFENSES ALONG A LATITUDINAL GRADIENT IN RANA TEMPORARIA
Authors: Laurila Anssi , Lindgren Beatrice , Laugen Ane T.
Published: May 2008

Antipredator defenses are expected to decrease toward higher latitudes because predation rates are predicted to decrease with latitude. However, latitudinal variation in predator avoidance and defense mechanisms has seldom been studied. We studied tadpole antipredator defenses in seven Rana temporaria populations collected along a 1500‐km latitudinal gradient across Sweden, along which previous studies have found increasing tadpole growth and development rates. In a laboratory common garden experiment, we measured behavioral and morphological defenses by raising tadpoles in the presence and absence of a predator (Aeshna dragonfly larva) in two temperature treatments. We also estimated tadpole survival in the presence of free‐ranging predators and compared predator densities between R. temporaria breeding ponds situated at low and high latitudes. Activity and foraging were generally positively correlated with latitude in the common garden experiment. While all populations responded to predator presence by decreasing activity and foraging, high‐latitude populations maintained higher activity levels in the presence of the predator. All populations exhibited defensive morphology in body and tail shape. However, whereas tail depth tended to increase with latitude in the presence of predator, it did not change with latitude in the absence of the predator. Predator presence generally increased larval period and decreased growth rate. In the southern populations, predator presence tended to have a negative effect on metamorphic size, whereas in the northern populations predators had little or a positive effect on size. Latitude of origin had a strong effect on survival in the presence of a free‐ranging predator, with high‐latitude tadpoles experiencing higher mortality than those from the low latitudes. In the wild, predator densities were significantly lower in high‐latitude than in mid‐latitude breeding ponds. Although the higher activity level in the northern populations seems to confer a significant survival disadvantage under predation risk, it is probably needed to maintain the high growth and development rates. However, the occurrence of R. temporaria at high latitudes may be facilitated by the lower predator densities in the north.
ABOVEGROUND AND BELOWGROUND EFFECTS OF SINGLE‐TREE REMOVALS IN NEW ZEALAND RAIN FOREST
Authors: Wardle David A. , Wiser Susan K. , Allen Robert B. , Doherty James E. , Bonner Karen I. , Williamson Wendy M.
Published: May 2008

There has been considerable recent interest in how human‐induced species loss affects community and ecosystem properties. These effects are particularly apparent when a commercially valuable species is harvested from an ecosystem, such as occurs through single‐tree harvesting or selective logging of desired timber species in natural forests. In New Zealand mixed‐species rain forests, single‐tree harvesting of the emergent gymnosperm Dacrydium cupressinum, or rimu, has been widespread. This harvesting has been contentious in part because of possible ecological impacts of Dacrydium removal on the remainder of the forest, but many of these effects remain unexplored. We identified an area where an unintended 40‐year “removal experiment” had been set up that involved selective extraction of individual Dacrydium trees. We measured aboveground and belowground variables at set distances from both individual live trees and stumps of trees harvested 40 years ago. Live trees had effects both above and below ground by affecting diversity and cover of several components of the vegetation (usually negatively), promoting soil C sequestration, enhancing ratios of soil C:P and N:P, and affecting community structure of soil microflora. These effects extended to 8 m from the tree base and were likely caused by poor‐quality litter and humus produced by the trees. Measurements for the stumps revealed strong legacy effects of prior presence of trees on some properties (e.g., cover by understory herbs and ferns, soil C sequestration, soil C:P and N:P ratios), but not others (e.g., soil fungal biomass, soil N concentration). These results suggest that the legacy of prior presence of Dacrydium may remain for several decades or centuries, and certainly well over 40 years. They also demonstrate that, while large Dacrydium individuals (and their removal) may have important effects in their immediate proximity, within a forest, these effects should only be important in localized patches containing high densities of large trees. Finally, this study emphasizes that deliberate extraction of a particular tree species from a forest can exert influences both above and below ground if the removed species has a different functional role than that of the other plant species present.
Factors influencing the partitioning and toxicity of nanotubes in the aquatic environment
Authors: Kennedy, Alan J , Hull Matthew S , Steevens Jeffery A , Dontsova Katerina M , Chappell Mark A , Gunter Jonas C , Weiss, Charles A
Published: May 2008

Carbon nanotubes (NTs) may be among the most useful engineered nanomaterials for structural applications but could be difficult to study in ecotoxicological evaluations using existing tools relative to nanomaterials with a lower aspect ratio. Whereas the hydrophobicity and van der Waals interactions of NTs may suggest aggregation and sedimentation in aquatic systems, consideration regarding how engineered surface modifications influence their environmental fate and toxicology is needed. Surface modifications (e.g., functional groups and coatings) are intended to create conditions to make NTs dispersible in aqueous suspension, as required for some applications. In the present study, column stability and settling experiments indicated that raw, multiwalled NTs (MWNTs) settled more rapidly than carbon black and activated carbon particles, suggesting sediment as the ultimate repository. The presence of functional groups, however, slowed the settling of MWNTs (increasing order of stability: hydroxyl > carboxyl > raw), especially in combination with natural organic matter (NOM). Stabilized MWNTs in high concentrations of NOM provided relevance for water transport and toxicity studies. Aqueous exposures to raw MWNTs decreased Ceriodaphnia dubia viability, but such effects were not observed during exposure to functionalized MWNTs (>80 mg/L). Sediment exposures of the amphipods Leptocheirus plumulosus and Hyalella azteca to different sizes of sediment-borne carbon particles at high concentration indicated mortality increased as particle size decreased, although raw MWNTs induced lower mortality (median lethal concentration [LC50], 50 to >264 g/kg) than carbon black (LC50, 18–40 g/kg) and activated carbon (LC50, 12–29 g/kg). Our findings stress that it may be inappropriate to classify all NTs into one category in terms of their environmental regulation.
Ecotoxicity of silica nanoparticles to the green alga pseudokirchneriella subcapitata: Importance of surface area
Authors: Van Hoecke Karen , De Schamphelaere Karel A. C , Van der Meeren Paul , Lcucas Stéphane , Janssen Colin R
Published: May 2008

To date, (eco)toxicological information on industrial nanoparticles is very limited. In the present study, the hypothesis that the ecotoxicity of nanoparticles (NPs) is related to their surface area and not to their mass was tested using a freshwater green algal species. Particle diameter and morphology were assessed using light scattering and electron microscopy techniques. To assess the toxicity of silica (SiO2) nanoparticles, the growth inhibition of the alga Pseudokirchneriella subcapitata when exposed to stable silica suspensions was monitored. Commercial LUDOX® suspensions of nanoparticles with 12.5 and 27.0 nm diameter were found to be toxic, with 72-h 20% effect concentrations for growth rate (ErC20) values ± standard deviation (n = 5) of 20.0 ± 5.0 and 28.8 ± 3.2 mg/L, respectively. The toxicity was attributable to the solid nanospheres, because no aggregation was observed and dissolution of the nanoparticles was negligible. When expressing the concentration as a surface area, the difference in toxicity was not significant. In the latter case, 72-h ErC20 values ± standard deviation (n = 5) were 4.7 ±1.2 and 3.9 ± 0.4 m2/L. Silica bulk material was found to be nontoxic up to 1 g/L. In an additional experiment with 100 mg/L of 12.5 and 27.0 nm SiO2 NPs, the interaction between the nanoparticles and algal cells was studied using transmission electron microscopy. Although the particles clearly adhered to the outer cell surface, no evidence was found for particle uptake.
Las Krudas, Spatial Practice, and the Performance of Diaspora
Authors: Armstead Ronni
Published: May 2008

This essay argues that female rappers Las Krudas are, with their music, engaging in trangressive spatial practice. Las Krudas are especially helping to disrupt the classificatory eye's orientalist gaze—which visually and aurally disciplines space through the distribution of bodies and voices—through their public performances. In the tourist zones the classificatory eye looks upon a sanitized space, producing, in concert with the ear, ordered visual and aural landscapes evocative of the “authentic” Cuba. I suggest that sound can make visible spatial practice. Las Krudas perform music and theater—aimed at disrupting the definition of who is authentically Cuban—in the heart of the tourist zone.

Widening the “circle of the we,” the space Las Krudas' music elaborates is seemingly heterotopic in that it may not be represented physically, yet it presupposes a “system of opening and closing that both isolates . . . and makes [it] impenetrable” (Foucault 1986, 26), making the heterotopia a space that erects its own fluid and autonomous boundaries. Las Krudas' music also expands diasporic space, transgresses geographic borders, and links sound to place: La Habana. In La Habana, Las Krudas borrow from shared diasporic resources (hip-hop culture/rap music, African drum rhythms and chants) when fashioning a musical aesthetic that allows for the articulation of the “local” as well as the “global.”

Finally, I move beyond Foucault's spatial model of disciplinary power by citing de Certeau's walking in the city as analogous to the agential speech act. I suggest that the creation of sound/aural landscape/music is a particularly powerful productive tool for speaking back to and ultimately destabilizing disciplinary power.
Meri Awaaz Suno
Authors: Sundar Pavitra
Published: May 2008

“Meri Awaaz Suno: Women, Vocality, and Nation in Hindi Cinema” analyzes the theme sony of the Bollywood blockbuster Lagaan (2001) to understand how playback singers' voices become sites for the construction of national identity. Lata Mangeshkar monopolized female playback singing for over four decades, and is known as the ideal voice of Indian femininity. The Lagaan theme song juxtaposes a saccharine, ultra-feminine Mangeshkaresque voice with two female choruses—one sensual and aggressive, the other light and airy. These varied female voices embody a range of sexual, national, and racial meanings, evoking an India that seems inclusive and progressive. Yet within Lagaan's utopian nation, and certainly within the film industry and broader social milieu, women with “ethnic” and sexually provocative voices are often deemed dangerous and are disallowed from speaking (or singing) for the nation. The social norms embedded in Lagaan's female singing voices thus reveal the limits that Hindi film music imposes on the voice of the nation, and vice versa.
Still
Authors: Moor Ayanah
Published: May 2008

Images of women surrounding male rap stars in music videos are as common as the jewel-encrusted subject matter of today's rap lyrics. Females are seen in packs hovering around male rap stars, playing the part of enthusiastic cheerleader or die-hard groupie. Rap music videos sell not only hip-hop culture, but also the very image of its women. They serve as eye candy designed to satisfy an assumed male video audience, affirming critiques of the culture as hyper-masculine and misogynist. “Still” is a series of photographs from contemporary rap music videos. These artworks invite a second look at the hip-hop video vixen, displaying an interest in moments unintended by music video narratives. Some stills reveal agency rather than victimization, while others provide reminders of the narrow representations of women in hip-hop.
Hip-Hop Honeys and Da Hustlaz
Authors: Miller-Young Mireille
Published: May 2008

Hip-hop pornography propels the conventions of the nearly soft-core hip-hop video to the extreme, the explicit, the hard-core. The convergence of the outlaw cultures of hip-hop and pornography offers a compelling narrative about how black sexual subjects define authority, legitimacy, legibility, and power. Hip-hop porn provides black women and men an arena for labor and accumulation as well as self-presentation, mediation, and mobility. As a space for work, survival, consumption, and identity-formation, the genre proffers an opportunity to explore the gendering of black (post)modern desires, as well as the potential to think through historical echoes of the current controversies and debates around exactly what constitutes “appropriate” black sexuality. Even as it offers a venue for acts of self-representation, pleasure, and exchange, hip-hop porn's brand of eroticism raises important questions about contemporary black gender and sexual politics. Within the space of hip-hop porn, these gender and sexual politics are produced within a sexual economy of illicit eroticism. The “illicit erotic” challenges ideas that fix the hypersexuality of the black body as always already repugnant, by using fetishized hypersexuality to strategically work with and through modern capitalism. This essay is primarily concerned with exploring how black sexual subjects engage illicit erotic economies as sites to self-fashion themselves according to the values and practices of “radical consumerism,” “play-labor,” and self- or counter-fetishization.
Hotep and Hip-Hop
Authors: McMurray Anaya
Published: May 2008

“Black Muslim women and hip-hop? . . . real Muslims don't listen to hip-hop.” For many it is almost unfathomable that black Muslim women would have any involvement with hip-hop music. While several scholars have explored the connections between hip-hop and Islam, hip-hop scholarship usually neglects in-depth conversations about black Muslim women. Using the examples of Erykah Badu, Eve, and myself, this paper explores the ways in which black Muslim women of the hip-hop generation use our music to negotiate faith and culture. Creating improvisation zones that highlight the flexibility of religion as it moves through cultures and spaces of resistance, black Muslim women successfully reconcile hotep and hip-hop.
Fundectomy-Evoked Osteopenia in Pigs Is Mediated by the Gastric-Hypothalamic-Pituitary Axis
Authors: Tatara Marcin R. , Krupski Witold , Śliwa Ewa , Maciejewski Ryszard , Dabrowski Andrzej
Published: May 2008

The aim of the study was to determine the effects of gastric impairment in pigs on the axial and peripheral skeletal system properties and to test the hypothesis that fundectomy-evoked osteopenia is related to disturbed gastric-hypothalamic-pituitary axis function. Forty-day-old male piglets were subjected to experimental fundectomy (FX group, n = 6) to induce osteopenia, while sham operation was performed in the controls (SHO group, n = 6). At the age of 8 months, serum samples were collected, and the animals were sacrificed to obtain lumbar vertebrae (L1–L6) and right humerus for analysis. Using quantitative computed tomography (QCT) and dual-energy x-ray absorptiometry (DEXA) methods, bone mineral density and bone mineral content of the vertebrae and humerus were measured. The compression and three-point bending tests were applied to determine mechanical properties of lumbar vertebrae and humerus, respectively. Furthermore, geometric properties of humerus were assessed. Serum concentrations of ghrelin, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and selected macro- and microelements were also determined. Performed fundectomy decreased body weight in pigs by 66% compared with pair-fed sham operated pigs ( P < 0.0001). Bone weight, bone mineral density, and bone mineral content of the lumbar vertebrae and humerus were significantly decreased in the fundectomized pigs ( P < 0.01). Mechanical parameters of the lumbar spine and humerus were decreased after the fundectomy, as well. Serum concentrations of ghrelin, GH, and IGF-1 were lowered by 74.4%, 90.6%, and 54.6% in the fundectomized pigs, respectively (all P < 0.001). Moreover, the serum concentrations of calcium, magnesium, iron and copper in the fundectomized animals were significantly decreased by 15.5%, 45.3%, 26.7%, and 26.2%, respectively ( P ≤ 0.05). In conclusion, the results obtained showed that both the disturbed gastric-hypothalamic-pituitary axis function and impaired mineral metabolism are associated with development of postfundectomy osteopenia of axial and peripheral skeleton in pigs.
Chemotherapy-Induced Mucositis Is Associated with Changes in Proteolytic Pathways
Authors: Leblond Jonathan , Le Pessot Florence , Hubert-Buron Aurélie , Duclos Célia , Vuichoud Jacques , Faure Magali , Breuillé Denis , Déchelotte Pierre , Coëffier Moïse
Published: May 2008

Mucositis, a common toxic side effect of chemotherapy, is characterized by an arrest of cell proliferation and a loss of gut barrier function, which may cause treatment reduction or withdrawal. Gut integrity depends on nutritional and metabolic factors, including the balance between protein synthesis and proteolysis. The effects of methotrexate (MTX; a frequently used chemotherapeutic agent) on intestinal proteolysis and gut barrier function were investigated in rats. Male Sprague-Dawley rats received 2.5 mg/kg of MTX subcutaneously during 3 days and were euthanized at Day 4 (D4) or Day 7 (D7). We observed at D4 that MTX induced mucosal damage and increased intestinal permeability (7-fold) and the mucosal concentration of interleukin (IL)-1β and IL-6 (4- to 6-fold). In addition, villus height and glutathione content significantly decreased. Intestinal proteolysis was also affected by MTX as cathepsin D activity increased at D4, whereas chymotrypsin-like proteasome activity decreased and calpain activities remained unaffected. At D7, cathepsin D activity was restored to control levels, but proteasome activity remained reduced. This disruption of proteolysis pathways strongly contributed to mucositis and requires further study. Lysosomal proteolytic activity may be considered the main proteolytic pathway responsible for alteration of mucosal integrity and intestinal permeability during mucositis, as cathespin D activity was found to be correlated with mucosal atrophy and intestinal permeability. Proteasome regulation could possibly be an adaptive process for survival. Future investigation is warranted to target proteolytic pathways with protective nutritional or pharmacological therapies during mucositis.
A BRIEF COMMUNICATION
Authors: Šošic-Jurjević Branka , Filipović Branko , Ajdžanović Vladimir , Brkić Dejan , Ristić Nataša , Stojanoski Milica Manojlović , Nestorović Nataša , Trifunović Svetlana , Sekulić Milka
Published: May 2008

Nutritional supplements containing soybean phytoestrogens, the isoflavones genistein (G) and daidzein (D), are increasingly used as alternative therapy for osteoporosis, cancer, and cardiovascular and other diseases with a frequency that increases with advancing age. In this study we examined the effects of subcutaneous administration of either G or D on serum lipid levels in orchidectomized (Orx) and intact (IA) middle-aged male rats, which are experimental models of andropause. Sixteen-month-old Wistar rats were treated with 10 mg/kg and 30mg/kg of either G or D. The control groups received testosterone, estradiol, or vehicle for 3 weeks, after which the total serum cholesterol (TC), low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), and total triglycerides (TT) were measured. Compared with the matching vehicle-treated controls, the higher doses of G and D and testosterone treatment significantly ( P < 0.05) lowered the TC and lipoprotein cholesterol levels. The greatest effect was observed regarding LDL-C in both Orx and IA males after G and D treatments, in which LDL-C decreased by more than 30%. The lower isoflavone doses induced a significant cholesterol-lowering effect ( P < 0.05) only in the Orx group. Like the estradiol treatment, the higher doses of G and D increased the TT levels in both rat models by more than 50% ( P < 0.05). The lower doses of isoflavones increased TT only in the Orx group. In male middle-aged rats, injections of higher doses of G and D decreased the serum cholesterol levels, as did testosterone injection, and brought about an increase in serum triglycerides similar to that observed after estradiol treatment.
Vitamin B12 Sources and Bioavailability
Authors: Watanabe Fumio
Published: May 2008

The usual dietary sources of vitamin B12 are animal foods, meat, milk, egg, fish, and shellfish. As the intrinsic factor-mediated intestinal absorption system is estimated to be saturated at about 1.5–2.0 μg per meal under physiologic conditions, vitamin B12 bioavailability significantly decreases with increasing intake of vitamin B12 per meal. The bioavailability of vitamin B12 in healthy humans from fish meat, sheep meat, and chicken meat averaged 42%, 56%–89%, and 61%–66%, respectively. Vitamin B12 in eggs seems to be poorly absorbed (< 9%) relative to other animal food products. In the Dietary Reference Intakes in the United States and Japan, it is assumed that 50% of dietary vitamin B12 is absorbed by healthy adults with normal gastro-intestinal function. Some plant foods, dried green and purple lavers (nori) contain substantial amounts of vitamin B12, although other edible algae contained none or only traces of vitamin B12. Most of the edible blue-green algae (cyanobacteria) used for human supplements predominately contain pseudovitamin B12, which is inactive in humans. The edible cyanobacteria are not suitable for use as vitamin B12 sources, especially in vegans. Fortified breakfast cereals are a particularly valuable source of vitamin B12 for vegans and elderly people. Production of some vitamin B12-enriched vegetables is also being devised.
Structure and Function of Basement Membranes
Authors: LeBleu Valerie S. , MacDonald Brian , Kalluri Raghu
Published: May 2008

Basement membranes (BMs) are present in every tissue of the human body. All epithelium and endothelium is in direct association with BMs. BMs are a composite of several large glycoproteins and form an organized scaffold to provide structural support to the tissue and also offer functional input to modulate cellular function. While collagen I is the most abundant protein in the human body, type IV collagen is the most abundant protein in BMs. Matrigel is commonly used as surrogate for BMs in many experiments, but this is a tumor-derived BM–like material and does not contain all of the components that natural BMs possess. The structure of BMs and their functional role in tissues are unique and unlike any other class of proteins in the human body. Increasing evidence suggests that BMs are unique signal input devices that likely fine tune cellular function. Additionally, the resulting endothelial and epithelial heterogeneity in human body is a direct contribution of cell-matrix interaction facilitated by the diverse compositions of BMs.
Progressive Resistance Training Without Volume Increases Does Not Alter Arterial Stiffness and Aortic Wave Reflection
Authors: Casey Darren P. , Beck Darren T. , Braith Randy W.
Published: May 2008

Endurance exercise is efficacious in reducing arterial stiffness. However, the effect of resistance training (RT) on arterial stiffening is controversial. High-intensity, high-volume RT has been shown to increase arterial stiffness in young adults. We tested the hypothesis that an RT protocol consisting of progressively higher intensity without concurrent increases in training volume would not elicit increases in either central or peripheral arterial stiffness or alter aortic pressure wave reflection in young men and women. The RT group ( n = 24; 21 ± 1 years) performed two sets of 8–12 repetitions to volitional fatigue on seven exercise machines on 3 days/week for 12 weeks, whereas the control group ( n = 18; 22 ± 1 years) did not perform RT. Central and peripheral arterial pulse wave velocity (PWV), aortic pressure wave reflection (augmentation index; AIx), brachial flow–mediated dilation (FMD), and plasma levels of nitrate/nitrite (NOx) and norepinephrine (NE) were measured before and after RT. RT increased the one-repetition maximum for the chest press and the leg extension ( P < 0.001). RT also increased lean body mass ( P < 0.01) and reduced body fat (%; P < 0.01). However, RT did not affect carotid-radial, carotid-femoral, and femoral-distal PWV (8.4 ± 0.2 vs. 8.0 ± 0.2 m/sec; 6.5 ± 0.1 vs. 6.3 ± 0.2 m/sec; 9.5 ± 0.3 vs. 9.5 ± 0.3 m/sec, respectively) or AIx (2.5% ± 2.3% vs. 4.8% ± 1.8 %, respectively). Additionally, no changes were observed in brachial FMD, NOx, NE, or blood pressures. These results suggest that an RT protocol consisting of progressively higher intensity without concurrent increases in training volume does not increase central or peripheral arterial stiffness or alter aortic pressure wave characteristics in young subjects.
Chymase Inhibition Reduces the Progression to Heart Failure After Autoimmune Myocarditis in Rats
Authors: Palaniyandi Suresh S. , Nagai Yusuke , Watanabe Kenichi , Ma Meilei , Veeraveedu Punniyakoti T. , Prakash Paras , Kamal Fadia A. , Abe Yuichi , Yamaguchi Ken’ichi , Tachikawa Hitoshi , Kodama Makoto , Aizawa Yoshifusa
Published: May 2008

Chymase has been known as a local angiotensin II–generating enzyme in the cardiovascular system in dogs, monkeys, hamsters, and humans; however, recently it was reported that chymase also has various other functions. Therefore, we decided to examine whether the inhibition of chymase improves disease conditions associated with the pathophysiology of dilated cardiomyopathy in rats and its possible mechanism of action as rat chymase is unable to produce angiotensin II. We examined the effect of TY-51469, a novel chymase inhibitor (0.1 mg/kg/day [group CYI-0.1, n = 15] and 1 mg/kg/day [group CYI-1, n = 15]), in myosin-immunized postmyocarditis rats. Another group of myosin-immunized rats was treated with vehicle (group V, n = 15). Age-matched normal rats without immunization (group N, n = 10) were also included in the study. After 4 weeks of treatment, we evaluated cardiac function; area of fibrosis; fibrogenesis; levels of transforming growth factor (TGF)-β1 and collagen III; hypertrophy and its marker, atrial natriuretic peptide (ANP); and mast cell activity. Survival rate and myocardial functions improved dose-dependently with chymase inhibitor treatment after myosin immunization. A reduction in the percent area of myocardial fibrosis, fibrogenesis, myocardial hypertrophy, and mast cell activity along with a reduction in TGF-β1, collagen III, and ANP levels in the myocardium were noted in postmyocarditis rats that received chymase inhibitor treatment. The treatment also decreased myocardial aldosterone synthase levels in those animals. Inhibition of chymase reduces the pathogenesis of postmyocarditis dilated cardiomyopathy and progression to heart failure by preventing the pathological remodeling and residual inflammation in rats.
Long-Chain Polyunsaturated Fatty Acids and the Regulation of Bone Metabolism
Authors: Poulsen Raewyn C. , Moughan Paul J. , Kruger Marlena C.
Published: May 2008

The role of prostaglandin E2 (PGE2) in the regulation of bone remodeling is well established. There is increasing evidence that various long-chain polyunsaturated fatty acids (LCPUFAs), as well as nonprostanoid LCPUFA metabolites, also have critical roles in regulating bone metabolism and may have therapeutic potential in the management of postmenopausal osteoporosis. Although only the 18-carbon precursors for the n-3 and n-6 LCPUFAs are deemed “dietary essential,” the ability of the body to convert these precursor fatty acids into the more highly unsaturated 20- and 22-carbon LCPUFAs decreases with aging, menopause, and various lifestyle factors (e.g., smoking). Increasing dietary LCPUFA intake increases tissue and blood LCPUFA concentrations, as well as the concentrations of their metabolites. Modification of dietary LCPUFA content, particularly increasing the intake of n-3 LCPUFAs, has been shown to minimize the decline in bone mass caused by menopause in women and ovariectomy in animal models. This review summarizes findings from both in vivo and in vitro studies and outlines the effects of LCPUFAs and their metabolites on calcium balance, osteoblastogenesis, osteoclastogenesis, and osteoblast and osteoclast function.
Voluntary Running Improves In Vivo Insulin Resistance in High-Salt Diet–Fed Rats
Authors: Qin Bolin , Oshida Yoshiharu , Li Ping , Kubota Masakazu , Nagasaki Masaru , Sato Yuzo
Published: May 2008

It is well known that exercise training, including voluntary running (VR), improves insulin resistance. However, the effect of VR on insulin resistance induced by high salt intake is unclear. The aim of this study was to determine whether VR would improve the glucose utilization in normal male Sprague-Dawley rats fed a high-salt diet (HSD) on 2-week early prevention and 1-week midway intervention protocols. In vivo glucose utilization was measured by euglycemic clamp technique. Further analyses of the possible changes in insulin signaling occurring in skeletal muscle were performed by Western blot and reverse transcription polymerase chain reaction (RT-PCR). The glucose infusion rates (GIRs) after 2 weeks of HSD feeding were decreased (HSD vs. control: 21.5 ± 0.8 vs. 27 ± 0.5 mg/kg body wt/min; P < 0.05), and improved by 2 weeks VR to 30.5 ± 1.5 mg/kg body wt/min. Additionally, the GIRs after 3 weeks of HSD feeding were decreased (HSD vs. control: 20.0 ± 0.3 vs. 26.5 ± 0.6 mg/kg body wt/min; P < 0.05), and they also improved by the third week of VR (28.5 ± 0.7 mg/ kg body wt/min vs. sedentary; P < 0.01). There were no differences in skeletal muscle for the total mass of insulin receptor-beta (IR-β), IR substrate-1 (IRS-1), Akt, and glucose transporter 4 (GLUT4) in any of the groups of 2 weeks of HSD loading control and VR. VR did not regulate the enhanced tyrosine phosphorylation of IR-β and IRS-1 by 2 weeks of HSD feeding. However, the enhanced serine phosphorylation of Akt and the tyrosine phosphorylation of GLUT4 were significantly inhibited by the early VR. HSD also impaired GLUT4 content in the plasma membrane and mRNA expression, but the decreases were improved by 2 weeks of VR. These results suggest that early voluntary exercise would prevent the development of insulin resistance induced by an HSD due in part by enhancing the impaired GLUT4 translocation and mRNA expression in skeletal muscle.
QiHong Prevents Death in Coxsackievirus B3–Induced Murine Myocarditis Through Inhibition of Virus Attachment and Penetration
Authors: Song Xiaodong , Liu Zhe , Wang Hu , Xin Ying , Wang Xiaojian , Chen Jingzhou , Shi Yi , Zhang Channa , Hui Rutai
Published: May 2008

Viral myocarditis affects about 5% to 20% of the population. So far, there are not many effective antiviral treatments available. QiHong, the combination of the extracts from Astragali (Huangqi), Rhadiola rosea (Hongjingtian), and Sophora flavescens (Kushen), was developed based on laboratory research. The aim of this study was to investigate the effect and mechanism of QiHong on coxsackievirus B3 (CVB3)–induced myocarditis. The antiviral activity of QiHong in vitro was evaluated on HeLa and Vero cells infected by CVB3. Ribavirin was chosen as positive control. Our results showed that QiHong possessed potent antiviral effects on CVB3 by sodium 3′-[1-(phenylamino-carbonyl)-3, 4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid and plaque-forming assay (50% inhibitory concentrations [IC50] were 7.16 ± 0.8 μg/ml and 2.63 ± 0.5 μg/ml, respectively). The 50% cytotoxicity concentration (CC50) was 16-fold higher in QiHong-treated cells than in ribavirin-treated cells. Time course studies demonstrated that the antiviral effect of QiHong was mainly found during 0–4 hrs of infection, and it blocked the attachment and penetration of CVB3 into cells. In vivo 4-week-old male Balb/C mice were used and inoculated intraperitoneally with CVB3 suspension or normal saline. At 48 hrs after inoculation, the infected mice were gavaged with QiHong or ribavirin. On Day 6, myocardial virus titers were significantly lower in the QiHong-treated group than in the viral-infected groups. On Day 14, QiHong significantly ameliorated CVB3-induced myocardium necrosis; on Day 28, QiHong treatment increased survival rate 4-fold compared with CVB3-infected controls (64% vs. 16%; P < 0.05). The results showed that QiHong is a very promising potent antiviral agent with a highly significant favorable effect on survival and pathologic changes in CVB3-induced myocarditis with less toxicity than ribavirin. The antiviral activity of QiHong is at least partially due to an inhibitory effect on virus attachment and penetration.
Mechanistic Analysis of Electroporation-Induced Cellular Uptake of Macromolecules
Authors: Zaharoff David A. , Henshaw Joshua W. , Mossop Brian , Yuan Fan
Published: May 2008

Pulsed electric field has been widely used as a nonviral gene delivery platform. The delivery efficiency can be improved through quantitative analysis of pore dynamics and intracellular transport of plasmid DNA. To this end, we investigated mechanisms of cellular uptake of macromolecules during electroporation. In the study, fluorescein isothiocyanate-labeled dextran (FD) with molecular weight of 4,000 (FD-4) or 2,000,000 (FD-2000) was added into suspensions of a murine mammary carcinoma cell (4T1) either before or at different time points (ie, 1, 2, or 10 sec) after the application of different pulsed electric fields (in high-voltage mode: 1.2–2.0 kV in amplitude, 99 μsec in duration, and 1–5 pulses; in low-voltage mode: 100–300 V in amplitude, 5–20 msec in duration, and 1–5 pulses). The intracellular concentrations of FD were quantified using a confocal microscopy technique. To understand transport mechanisms, a mathematical model was developed for numerical simulation of cellular uptake. We observed that the maximum intracellular concentration of FD-2000 was less than 3% of that in the pulsing medium. The intracellular concentrations increased linearly with pulse number and amplitude. In addition, the intracellular concentration of FD-2000 was ~ 40% lower than that of FD-4 under identical pulsing conditions. The numerical simulations predicted that the pores larger than FD-4 lasted <10 msec after the application of pulsed fields if the simulated concentrations were on the same order of magnitude as the experimental data. In addition, the simulation results indicated that diffusion was negligible for cellular uptake of FD molecules. Taken together, the data suggested that large pores induced in the membrane by pulsed electric fields disappeared rapidly after pulse application and convection was likely to be the dominant mode of transport for cellular uptake of uncharged macromolecules.