bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue concentration of transforming growth factor β1 and basic fibroblast growth factor in skin wounds created with a CO2 laser and scalpel: A comparative experimental study, using an animal model of skin resurfacing
Authors: Manolis Evangelos N. , Kaklamanos Ioannis G. , Spanakis Nicholas , Filippou Dimitrios K. , Panagiotaropoulos Theophanis , Tsakris Athanassios , Siomos Konstadinos
Published: March 2007

Although a number of ablative‐laser techniques based on CO2 and Er: YAG laser devices have been successfully developed and used in the clinical setting, the bio‐molecular processes influencing wound healing after exposure to laser energy are not well elucidated. In this study, we aim to assess the impact of the mechanism of injury on the secretion of transforming growth factor β1 (TGF‐β1) and basic fibroblast growth factor (bFGF) in various stages of wound healing, in wounds created with a CO2 laser and scalpel. Ten Wistar rats were used to determine the levels of growth factor proteins TGF‐β1 and bFGF after CO2 laser‐ and scalpel‐induced skin injury. Tissue was excised on day 0 for untreated skin (control sites), and on days 1, 10, 30, and 90 following laser and scalpel surgery. Specimens were processed for histopathological analysis and for determining the concentration of growth factors by a Western blot technique. The concentration of TGF‐β1 increased markedly, at day 1 postinjury, from a baseline of 130±16 mm2 (mean surface area of blotted‐protein lanes) to 261±23 mm2 and 394±22 mm2 for laser‐inflicted injury and scalpel wounds, respectively; the latter values were found to differ significantly (p<0.001). The concentration of b‐FGF on day 10 postinjury differed significantly (p<0.001) between the laser sites (553±45 mm2) and the corresponding scalpel sites (418±41 mm2). Laser energy alters local tissue secretion of TGF‐β1 and bFGF of skin injuries created with the CO2 laser compared with wounds created with a scalpel. These differences might have an impact on various aspects of wound healing of skin injuries created by a laser.
Local injection of insulin‐zinc stimulates DNA synthesis in skin donor site wound
Authors: Zhang Xiao‐jun , Chinkes David L. , Sadagopa Ramanujam V. M. , Wolfe Robert R.
Published: March 2007

Our group has reported the ability of local insulin‐zinc injection to accelerate skin wound healing. This experiment was conducted to investigate the metabolic mechanisms of locally injected insulin‐zinc in accelerating wound healing. A partial thickness skin donor site wound was created on the back, and indwelling catheters were placed in the carotid artery and jugular vein in anesthetized rabbits. On day 7 after injury, the wound was either injected with 0.2 U of insulin‐zinc, 0.4 μg zinc (the amount of zinc in 0.2 U of insulin‐zinc), or not injected; stable isotope tracers were infused for measurement of wound DNA synthetic rate as a reflection of cell proliferation. Wound protein synthetic and breakdown rates were also measured. The local insulin‐zinc injection increased wound insulin concentration from below 5 pmol/L to 1,260±780 pmol/L with minor changes in blood glucose concentration that did not require exogenous glucose replacement. In the insulin‐zinc–injected wound, the total DNA synthetic rate was increased by ∼50% (p<0.05 vs. control). In the zinc‐injected wound, whereas total DNA synthetic rate was increased (p<0.05 vs. control), net protein deposition (synthesis–breakdown) was less (p<0.05) than those in the control and insulin‐zinc groups. We conclude that local insulin‐zinc injection stimulates wound DNA synthesis, which would be expected to accelerate wound reepithelialization.
Hyperbaric oxygen stimulates epidermal reconstruction in human skin equivalents
Authors: Kairuz Evette , Upton Zee , Dawson Rebecca A. , Malda Jos
Published: March 2007

The crucial role of oxygen during the complex process of wound healing has been extensively described. In chronic or nonhealing wounds, much evidence has been reported indicating that a lack of oxygen is a major contributing factor. Although still controversial, the therapeutic application of hyperbaric oxygen (HBO) therapy can aid the healing of chronic wounds. However, how HBO affects reepithelization, involving processes such as keratinocyte proliferation and differentiation, remains unclear. We therefore used a three‐dimensional human skin–equivalent (HSE) model to investigate the effects of daily 90‐minute HBO treatments on the reconstruction of an epidermis. Epidermal markers of proliferation, differentiation, and basement membrane components associated with a developing epidermis, including p63, collagen type IV, and cytokeratins 6, 10, and 14, were evaluated. Morphometric analysis of hematoxylin and eosin‐stained cross sections revealed that HBO treatments significantly accelerated cornification of the stratum corneum compared with controls. Protein expression as determined by immunohistochemical analysis confirmed the accelerated epidermal maturation. In addition, early keratinocyte migration was enhanced by HBO. Thus, HBO treatments stimulate epidermal reconstruction in an HSE. These results further support the importance of oxygen during the process of wound healing and the potential role of HBO therapy in cutaneous wound healing.
Digit tip regrowth and differential gene expression in MRL/Mpj, DBA/2, and C57BL/6 mice
Authors: Chadwick Robert B. , Bu Liming , Yu Hongrun , Hu Yan , Wergedal Jon E. , Mohan Subburaman , Baylink David J.
Published: March 2007

MRL/Mpj mice are the only known strain of mouse that can regenerate cardiac lesions and completely heal ear punches without scarring. This study was undertaken to determine if MRL mice also have greater regrowth capabilities in amputated digit tips. Right paw digit tips of neonatal MRL mice were dissected, with the left front paws as uncut controls. Controls used for regrowth comparison were the DBA/2 and C57BL/6 inbred mouse strains. Consecutive x‐ray images were captured of front paws at 0, 7, 14, 21, and 28 days postamputation. MRL mouse digit tips were found to distally regrow more quickly and reform nails partially and completely to a greater degree in comparison with DBA and B6 mice (p<0.05). We next undertook microarray expression analysis to identify the genes involved in digit tip regrowth. Four hundred genes out of 15,000 were significantly differentially expressed (p<0.05) in MRL, DBA, and B6 mice at day 4 in comparison with day 0 control tissue. Multiple differences between MRL, DBA, and B6 strains were found in genes that are implicated in the WNT signaling pathway and transcription. We conclude that MRL mice regrow digits distally more rapidly and partially and completely regrow nails to a greater degree than B6 and DBA strains. This enhanced regrowth is likely due to strain‐specific increased expression of genes involved in growth and development.
FIRST REPORT OF THE CYANOTOXIN ANATOXIN‐A FROM APHANIZOMENON ISSATSCHENKOI (CYANOBACTERIA)1
Authors: Wood Susanna A. , Rasmussen John Paul , Holland Patrick T. , Campbell Rebecca , Crowe Anna L. M.
Published: March 2007

The taxonomy and toxicity of a single‐filament isolate from a filamentous cyanobacterial bloom in Lake Hakanoa (New Zealand) were examined by microscopy and liquid chromatography–mass spectrometry. Based on a morphological examination of environmental and cultured material, strain CAWBG02 was identified as Raphidiopsis mediterranea Skuja; however, subsequent phylogenetic analysis of the 16S rRNA gene sequence demonstrated that CAWBG02 was most likely to be a single culture of Aphanizomenon issatschenkoi (Usacev) Proshkina‐Lavrenko. Toxin testing confirmed that the original bloom and A. issatschenkoi isolate produced anatoxin‐a but did not produce homoanatoxin‐a or any cylindrospermopsins, saxitoxins, or microcystins. Despite the absence of cylindrospermopsin production, genes implicated in the biosynthesis of cylindrospermopsin were successfully amplified from A. issatschenkoi strain CAWBG02. To our knowledge, this is the first confirmation of an anatoxin‐a‐producing species in the Southern Hemisphere and the first report of anatoxin‐a production by A. issatschenkoi.
CHARACTER EVOLUTION IN POLYKRIKOID DINOFLAGELLATES1
Authors: Hoppenrath Mona , Leander Brian S.
Published: March 2007

A synthesis of available data on the morphological diversity of polykrikoid dinoflagellates allowed us to formulate a hypothesis of relationships that help explain character evolution within the group. Phylogenetic analyses of new SSU rDNA sequences from Pheopolykrikos beauchampii Chatton, Polykrikos kofoidii Chatton, and Polykrikos lebourae Herdman helped refine this hypothetical framework. Our results demonstrated that “pseudocolonies” in dinoflagellates evolved convergently at least three times independently from different Gymnodinium‐like ancestors: once in haplozoans; once in Ph. beauchampii; and at least once within a lineage containing Ph. hartmannii, P. kofoidii, and P. lebourae. The Gymnodiniales sensu stricto was strongly supported by the data, and the type species for the genus, namely Gymnodinium fuscum (Ehrenb.) F. Stein, formed the nearest sister lineage to a well‐supported Polykrikos clade. The best synapomorphy for the Polykrikos clade was the presence of two nuclei irrespective of zooid number. Two unidentified Gymnodinium species formed the nearest sister clade to Ph. beauchampii, which has four nuclei and four zooids per pseudocolony. The chain‐forming dinoflagellate G. catenatum L. W. Graham branched closely to the clade containing all members of Polykrikos and Pheopolykrikos, suggesting that an ancestral capacity toward chain formation existed before the evolution of pseudocolonies in this group. Our results also clarified the phylogenetic significance of nematocysts, ocelloids, and photosynthesis in reconstructing the evolution of polykrikoids and warnowiids. The molecular phylogenies exposed taxonomic problems associated with Polykrikos, Pheopolykrikos, and Gymnodinium, and suggested that a revision for some of these genera is warranted.
RECOGNIZING DINOFLAGELLATE SPECIES USING ITS rDNA SEQUENCES1
Authors: Wayne Litaker R. , Vandersea Mark W. , Kibler Steven R. , Reece Kimberly S. , Stokes Nancy A. , Lutzoni François M. , Yonish Bryan A. , West Melissa A. , Black Megan N. D. , Tester Patricia A.
Published: March 2007

Dinoflagellate taxonomy is based primarily on morphology and morphometric data that can be difficult to obtain. In contrast, molecular data can be rapidly and cost‐effectively acquired, which has led to a rapid accumulation of sequence data in GenBank. Currently there are no systematic criteria for utilizing taxonomically unassigned sequence data to identify putative species that could in turn serve as a basis for testable hypotheses concerning the taxonomy, diversity, distribution, and toxicity of these organisms. The goal of this research was to evaluate whether simple, uncorrected genetic distances (p) calculated using ITS1/5.8S/ITS2 (ITS region) rDNA sequences could be used to develop criteria for recognizing putative species before formal morphological evaluation and classification. The current analysis used sequences from 81 dinoflagellate species belonging to 14 genera. For this diverse assemblage of dinoflagellate species, the within‐species genetic distances between ITS region copies (p=0.000–0.021 substitutions per site) were consistently less than those observed between species (p=0.042–0.580). Our results indicate that a between‐species uncorrected genetic distance of p≥0.04 could be used to delineate most free‐living dinoflagellate species. Recently evolved species, however, may have ITS p values <0.04 and would require more extensive morphological and genetic analyses to resolve. For most species, the sequence of the dominant ITS region allele has the potential to serve as a unique species‐specific “DNA barcode” that could be used for the rapid identification of dinoflagellates in field and laboratory studies.
Insurance, Bond Covenants, and Under‐ or Over‐investment With Risky Asset Reconstitution
Authors: Hau Arthur
Published: March 2007

Abstract

Traditional theory predicts that the shareholders of a limited liability company financed partly by bonds may underinvest by not replacing damaged company assets. It also precludes the possibility of overinvestment. By relaxing the restrictive assumption maintained under traditional theory, namely, that the effects of reconstituting damaged assets are nonstochastic, this article shows that both over and underinvestment are possible. It is shown that these moral hazard problems can be mitigated by incorporating appropriate insurance requirements into bond covenants. Moreover, it is shown that the insurance requirements for alleviating underinvestment and overinvestment are quite different. Particularly, for underinvestment, the required insurance only needs to make the bonds riskless in the best asset reconstitution states of the loss states in which the company value falls short of the promised bond repayment; however, for overinvestment, the required insurance should make the bonds totally riskless. The difference in insurance requirements is especially important when insurance is actuarially unfavorable such that more‐than‐required insurance is always undesirable.
Adverse Selection in Term Life Insurance Purchasing due to the BRCA1/2 Genetic Test and Elastic Demand
Authors: Viswanathan Krupa S. , Lemaire Jean , Withers Kate , Armstrong Katrina , Baumritter Agnieszka , Hershey John C. , Pauly Mark V. , Asch David A.
Published: March 2007

Abstract

Consumer groups fear that the use of genetic testing information in insurance underwriting might lead to the creation of an underclass of individuals who cannot obtain insurance; thus, these groups want to ban insurance companies from accessing genetic test results. Insurers contend that such a ban might lead to adverse selection that could threaten their financial solvency. To investigate the potential effect of adverse selection in a term life insurance market, a discrete‐time, discrete‐state, Markov chain is used to track the evolution of twelve closed cohorts of women, differentiated by family history of breast and ovarian cancer and age at issue of a 20‐year annually renewable term life insurance policy. The insurance demand behavior of these women is tracked, incorporating elastic demand for insurance. During the 20‐year period, women may get tested for BRCA1/2 mutations. Each year, the insurer calculates the expected premiums and expected future benefit payouts which determine the following year's premium schedule. At the end of each policy year, women can change their life insurance benefit, influenced by their testing status and premium changes. Adverse selection could result from (i) differentiated benefits following test results; (ii) differentiated lapse rates according to test results; and (iii) differentiated reactions to price increases. It is concluded that with realistic estimates of behavioral parameters, adverse selection could be a manageable problem for insurers.
Securitization of Longevity Risk: Pricing Survivor Bonds With Wang Transform in the Lee‐Carter Framework
Authors: Denuit Michel , Devolder Pierre , Goderniaux Anne‐Cécile
Published: March 2007

Abstract

Longevity risk is a major issue for insurers and pension funds, especially in the selling of annuity products. In that respect, securitization of this risk could offer great opportunities for hedging. This article proposes to design survivor bonds which could be issued directly by insurers. In order to guaranty some transparency in the product, the survivor bond is based on a public mortality index. The classical Lee‐Carter model for mortality forecasting is used to price a risky coupon survivor bond based on this index.
Household Life Cycle Protection: Life Insurance Holdings, Financial Vulnerability, and Portfolio Implications
Authors: Lin Yijia , Grace Martin F.
Published: March 2007

Abstract

Using the Survey of Consumer Finances, we examine the life cycle demand for different types of life insurance. Specifically, we test for the consumer's aversion to income volatility resulting from the death of a household's wage‐earner through the purchase of life insurance. We first develop a financial vulnerability index to control for the risk to the household. We then examine the life cycle demand for life insurance using several definitions of life insurance. We find, in contrast to previous research, that there is a relationship between financial vulnerability and the amount of term life or total life insurance purchased. In addition, we find older consumers use less life insurance to protect a certain level of financial vulnerability than younger consumers. Secondly, our study provides evidence that life insurance demand is jointly determined as part of a household's portfolio. Finally, we consider the impact of family members' nonmonetary contribution on the household's life cycle protection decision. Our results provide some evidence that households take into account the value of nonmonetary contribution in their insurance purchase.
Wealth, Income, and Optimal Insurance
Authors: Lee Kangoh
Published: March 2007

Abstract

This article considers the decision to purchase insurance against possible losses of a property or wealth. The decision involves a standard economic trade‐off between the benefit of protection against loss and the cost of insurance premium. The premium is paid out of the income and decreases the consumption of other goods and services, rather than out of wealth and decreases the property or wealth. The demand for insurance depends mainly on the income and preferences. As a result, unlike in the standard model, a fair premium is neither necessary nor sufficient for the optimality of full coverage insurance. Rather, the individuals with higher incomes purchase full coverage insurance even at unfair prices of insurance while the individuals with lower income purchase partial coverage insurance at a fair price.
Population ecology and prey consumption by fathead minnows in prairie wetlands: importance of detritus and larval fish
Authors: Herwig B. R. , Zimmer K. D.
Published: March 2007

Abstract –  The fathead minnow Pimephales promelas occurs in high densities in wetlands of the prairie pothole region (PPR) of North America, but food resources sustaining these populations are poorly known. We assessed population dynamics and prey consumption of fathead minnow populations in three PPR wetlands for 2 years. Fish density peaked at 107 fish per m2 for all age classes combined. Larval and juvenile fish dominated these populations in terms of abundance and accounted for 83% of total prey consumption. Detritus dominated fish diets, representing 53%, 40% and 79% of diet mass for larval, juvenile and adult fish respectively. Detritus consumption was positively related to minnow density and negatively related to invertebrate abundance, but only for adult fish. Seasonal production:biomass ratios were unrelated to proportions of detritus in the diet for all ages of fish, indicating that detritus is an important food resource capable of meeting metabolic demands and sustaining fish growth in high‐density populations. Detritus consumption may also weaken links between abundance of invertebrate prey and minnows, promoting dense fish populations with strong, consistent influences on wetland ecosystems.
Evaluation of passive integrated transponder tags for marking the bullhead (Cottus gobio), a small benthic freshwater fish: effects on survival, growth and swimming capacity
Authors: Knaepkens G. , Maerten E. , Tudorache C. , De Boeck G. , Eens M.
Published: March 2007

Abstract –  This study examined potential adverse effects of surgically implanted passive integrated transponder (PIT) tags (12 × 2.1 mm) on bullhead (Cottus gobio L.) of three different length‐classes (I: 50–64 mm, II: 65–79 mm, III: 80–94 mm). During a 7‐week laboratory experiment, the rate of PIT tag loss, incision closure time, survival, growth and swimming capacity were tested. The PIT tag weight to fish body weight ratio varied between 1.04% and 4.85%. The mean incision closure time differed significantly among length‐classes and varied between 2.8 (I) and 4.3 (III) weeks. Nevertheless, PIT tag retention did not differ among length‐classes and was ≥90%. The survival of untagged, sham‐tagged and PIT‐tagged bullheads was ≥90% and did not differ within or among length‐classes. Finally, within each length‐class, there was no difference in growth and swimming capacity among treatments. Hence, these results suggest the applicability of PIT tags for individually tagging bullheads ≥50 mm.
A mineralization‐associated membrane protein plays a role in the biological functions of the peptide‐coated bovine hydroxyapatite
Authors: Yuan K. , Huang J.‐S. , Hsu C.‐W. , Hung I.‐J.
Published: March 2007

Background and Objective:  Anorganic bovine mineral coated with a cell‐binding peptide (P‐15) is superior to anorganic bovine mineral alone in the treatment of periodontal osseous defects. However, the molecular interactions between P‐15 and periodontal ligament fibroblasts remain unclear.

Material and Methods:  We first compared the in vitro osteogenic activities between periodontal ligament fibroblasts cultured with anorganic bovine mineral alone and with the P‐15/anorganic bovine mineral combination. We then harvested the periodontal ligament cell lysate, incubated it with various graft materials, and then washed it to remove unbound proteins. The bound proteins were eluted from graft materials and analyzed using electrophoresis, followed by mass spectrometry and then western blotting. Finally, a neutralizing antibody against one bound protein was added to the cell cultures to repeat the osteogenic assays to clarify its role in the in vitro effects of the P‐15/anorganic bovine mineral combination.

Results:  Cells treated with P‐15/anorganic bovine mineral were more viable and showed greater osteogenic activities than cells treated with anorganic bovine mineral alone and the no‐graft control. Annexin II, a mineralization‐associated protein, bound to P‐15/anorganic bovine mineral significantly more than to anorganic bovine mineral alone. The addition of neutralizing antibody for annexin II decreased the osteogenic activities of the P‐15/anorganic bovine mineral combination.

Conclusion:  Annexin II of periodontal ligament fibroblasts interacted with the peptide of P‐15, and was partially responsible for better in vitro osteogenesis in the P‐15 graft.
Human β defensin‐1 and ‐2 expression in the gingiva of patients with specific periodontal diseases
Authors: Vardar‐Sengul S. , Demirci T. , Sen B. H. , Erkizan V. , Kurulgan E. , Baylas H.
Published: March 2007

Background and Objective:  β defensin antimicrobial peptides are important in epithelial innate immunity, and their differential expression is associated with periodontal diseases. The aims of this study were to determine the mRNA expression of human β defensin‐1 and ‐2 in the gingival tissue of patients with gingivitis, aggressive periodontitis and chronic periodontitis, and to evaluate the relationship between defensin expression and type and/or severity of periodontal destruction.

Material and Methods:  Fifteen patients in each group with gingivitis, aggressive periodontitis and chronic periodontitis, and 10 healthy subjects, were included in the study (n = 55). The periodontal status of the subjects was determined by periodontal clinical measurements and radiographical evaluations. Transcriptional levels of human β defensin‐1 and ‐2 genes in gingival samples were assessed by using the quantitative real‐time polymerase chain reaction technique, and the data were evaluated statistically by the relative expression Software Tool 2 for groupwise comparisons.

Results:  Expression of the human β defensin‐1 gene was lower in gingivitis and aggressive periodontitis groups, and significantly higher in the chronic periodontitis group, than in the control group (p < 0.001). Human β defensin‐2 mRNA expression in the gingivitis group was lower than in the control group; however, the difference was statistically significant only in half of the gingivitis patients (p < 0.001). Human β defensin‐2 mRNA levels were higher in some chronic periodontitis patients, but lower in the others when compared with the control group (p < 0.001). Expression of the human β defensin‐2 gene increased in the aggressive periodontitis group relative to the control group.

Conclusion:  This study suggests that human β defensin‐1 and ‐2 genes in the gingival epithelium show differential expression in patients with specific periodontal diseases, and aggressive and chronic periodontitis types demonstrate different gingival β defensin‐1 and ‐2 expression patterns.
Use of the Reviscometer® for measuring cosmetics‐induced skin surface effects
Authors: Paye M. , Mac‐Mary S. , Elkhyat A. , Tarrit C. , Mermet P. , Humbert P. H.
Published: March 2007

Background/purpose: The Reviscometer® RVM600 that measures resonance running time (RRT) has been shown to be inversely related to the skin stiffness. However, very few publications describe the use of this instrument for testing the effect of cosmetic products.

Methods: Slight xerotic skin condition was induced by using an alkaline soap for 1 week. Skin has then been rehydrated with a lotion or further dehydrated and dried with sodium lauryl sulfate (SLS). Skin condition at the different stages of the study was evaluated by visual assessment for dryness and redness and by non‐invasive methods (Corneometer®, Cutometer®, Reviscometer®, Evaporimeter® and squamometry).

Results: All methods showed highly significant changes after the slight drying phase with the soap usage. They illustrated skin repair after lotion treatment and further skin impairment after SLS application. Nevertheless, the Reviscometer® was able to better statistically discriminate between the treatments (water, lotion, SLS) than the Cutometer®. Measurement of the RRT along the transversal axis of the forearms was the most sensitive for differentiating between normal and dry skin and between the treatments on the basis of skin mechanical properties.

Conclusion: The Reviscometer® RVM600 is a sensitive instrument able to detect slight skin surface effect of cosmetics. Combined with published literature on the interpretation of RRT measurements on polymeric gel or in different skin conditions (elderly skin and photoaged skin), the Reviscometer® looks to be a recommendable instrument to measure slight changes in SC stiffness/suppleness induced by cosmetic products.
A device for the color measurement and detection of spots on the skin
Authors: Pladellorens Josep , Pintó Agustí , Segura Jordi , Cadevall Cristina , Antó Joan , Pujol Jaume , Vilaseca Meritxell , Coll Joaquín
Published: March 2007

Background/purpose: In this work, we present a new and fast easy‐to‐use device that allows the measurement of color and the detection of spots on the human skin. The developed device is highly practical for relatively untrained operators and uses inexpensive consumer equipment, such as a CCD color camera, a light source composed of LEDs and a laptop. The knowledge of the color of the skin and the detection of spots can be useful in several areas such as in dermatology applications, the cosmetics industry, the biometrics field, health care, etc.

Methods: In order to perform these measurements the system takes a picture of the skin. After that, the operator selects the region of the skin to be analyzed on the displayed image and the system provides the CIELAB color coordinates, the chroma and the ITA parameter (Individual Tipology Angle), allowing the comparison with other reference images by means of CIELAB color differences. The system also detects spots, such as freckles, age spots, sunspots, pimples, black heads, etc., in a determined region, allowing the objective measurement of their size and area.

Results: The colorimetric information provided by a conventional spectrophotometer for the tested samples and the computed values obtained with the new developed system are quite similar, meaning that the developed system can be used to perform color measurements with relatively high accuracy. On the other hand, the feasibility of the system in order to detect and measure spots on the human skin has also been checked over a great amount of images, obtaining results with high precision.

Conclusion: In this work, we present a new system that may be very useful in order to measure the color and to detect spots of the skin. Its portability and easy applicability will be very useful in dermatologic and cosmetic studies.
Selective detection of superoxide anion radicals generated from macrophages by using a novel fluorescent probe
Authors: Gao Jing Jing , Xu Ke Hua , Tang Bo , Yin Ling Ling , Yang Gui Wen , An Li Guo
Published: March 2007

Quantitation of superoxide radical (O 2–·) production at the site of radical generation remains challenging. A simple method to detect nanomolar to micromolar levels of superoxide radical in aqueous solution has been developed and optimized. This method is based on the efficient trapping of O2–· using a novel fluorescent probe (2‐chloro‐1,3‐dibenzothiazolinecyclohexene), coupled with a spectra character‐signaling increase event. A high‐specificity and high‐sensitivity fluorescent probe was synthesized in‐house and used to image O2–· in living cells. Better selectivity for O2–· over competing cellular reactive oxygen species and some biological compounds illustrates the advantages of our method. Under optimal conditions, the linear calibration range for superoxide anion radicals was 5.03 × 10−9−3.33 × 10−6 m. The detection limit was 1.68 × 10−9 m. Fluorescence images of probe‐stained macrophages stimulated with 4β‐phorbol 12‐myristate 13‐acetate were obtained successfully using a confocal laser scanning microscope.
Gender and Biodiversity: A New Approach to Linking Environment and Development
Authors: Momsen Janet Henshall
Published: March 2007

The 1992 Convention on Biological Conservation and the International Treaty on Plant Genetic Resources for Food and Agriculture (1996) reflect the growing importance of biodiversity for environmental conservation and as a way of maintaining the genetic variety needed for plant breeding and providing new sources of medicines. More recently, agrobiodiversity has been seen as vital for food security in developing countries. This article considers the need to understand decision‐making for biodiversity at the grassroots. To achieve this, gender roles, as influenced by gender divisions of labour in food production and the gendered use of different environmental spaces, have to be considered. Women's roles in seed selection and seed saving and use of wild plants for food and medicines play a major role in biodiversity conservation, but these roles are not unchanging and are increasingly influenced by global trade networks and geographical context.
Intergenerational Geographies: Age Relations, Segregation and Re‐engagements
Authors: Vanderbeck Robert M.
Published: March 2007

Research on age in geography has become highly compartmentalized into separate literatures on younger and older generations that rarely intersect. As such, the geographies of intergenerational relationships – and particularly, extrafamilial intergenerational relationships – remain substantially under‐researched. This essay reviews how geographers have approached issues of intergenerational relationships while also drawing on recent work from other fields (including sociology, anthropology and queer theory) that can extend current thinking on the geographies of intergenerationality and age relations. How does space facilitate and limit intergenerational contact and relationships? How do the geographies of intergenerational relationships vary between social groups and contexts? And if generational separation and segregation are problems (as a substantial body of work suggests), how can this be ameliorated? Throughout the essay, I examine how social scientists have attempted to address these questions while also identifying the significant gaps that remain in our understanding.
Relationship Between Solidification Depth of Granitic Rocks and Formation of Hydrothermal Ore Deposits
Authors: Uchida Etsuo , Endo Sho , Makino Mitsutoshi
Published: March 2007

Chemical analysis of biotite in representative granitic rocks in Japan shows that the total Al (TAl) content changes with the metal type of the accompanying hydrothermal ore deposits and increases in the following order: Pb‐Zn and Mo deposits < Cu‐Fe and Sn deposits < W deposits < non‐mineralized granitic rocks. The TAl content of biotite in granitic rocks may be a useful indicator for distinguishing between mineralized and non‐mineralized granitic rocks. A good positive correlation is seen between the TAl content of biotite and the solidification pressure of the granitic rocks estimated by sphalerite and hornblende geobarometers and the mineral assemblages of the surrounding rocks. These facts suggest that the TAl content of biotite can be used to estimate the solidification pressure (P) of the granitic rocks. The following empirical equation was obtained:

image

where TAl designates the total Al content in biotite on the basis O = 22. According to the obtained biotite geobarometer, it is estimated that Pb‐Zn and Mo deposits were formed at pressures below 1 kb, Cu‐Fe and Sn deposits at 1–2 kb, W deposits at 2–3 kb and non‐mineralized granitic rocks were solidified at pressures above 3 kb.
Geology and Metallogenesis of the Sawayaerdun Gold Deposit in the Southwestern Tianshan Mountains, Xinjiang, China
Authors: Yang Fuquan , Mao Jingwen , Wang Yitian , Bierlein Frank P. , Ye Huishou , Li Mengwen , Zhao Caisheng , Ye Jinhua
Published: March 2007

The Sawayaerdun gold deposit, located in Wuqia County, Southwest Tianshan, China, occurs in Upper Silurian and Lower Devonian low‐grade metamorphic carbonaceous turbidites. The orebodies are controlled by a series of NE‐NNE‐trending, brittle–ductile shear zones. Twenty‐four gold mineralized zones have been recognized in the Sawayaerdun ore deposit. Among these, the up to 4‐km‐long and 200‐m wide No. IV mineralized zone is economically the most important. The average gold grade is 1–6 g/t. Gold reserves of the Sawayaerdun deposit have been identified at approximately 37 tonnes and an inferred resource of 123 tonnes. Hydrothermal alteration is characterized by silicification, pyritization, arsenopyritization, sericitization, carbonatization and chloritization. On the basis of field evidence and petrographic analysis, five stages of vein emplacement and hydrothermal mineralization can be distinguished: stage 1, early quartz stage, characterized by the occurrence of quartz veins; stage 2, arsenopyrite–pyrite–quartz stage, characterized by the formation of auriferous quartz veinlets and stockworks; stage 3, polymetallic sulfide quartz stage, characterized by the presence of auriferous polymetallic sulfide quartz veinlets and stockworks; stage 4, antimony–quartz stage, characterized by the formation of stibnite–jamesonite quartz veins; and stage 5, quartz–carbonate vein stage. Stages 2 and 3 represent the main gold mineralization, with stage 4 representing a major antimony mineralization episode in the Sawayaerdun deposit. Two types of fluid inclusion, namely H2O–NaCl and H2O–CO2–NaCl types, have been recognized in quartz and calcite. Aqueous inclusions show a wide range of homogenization temperatures from 125 to 340°C, and can be correlated with the mineralization stage during which the inclusions formed. Similarly, salinities and densities of these fluids range for each stage of mineralization from 2.57 to 22 equivalent wt% NaCl and 0.76 to 1.05 g/cm3, respectively. The ore‐forming fluids thus are representative of a medium‐ to low‐temperature, low‐ to medium‐salinity H2O–NaCl–CO2–CH4–N2system. The δ34SCDTvalues of sulfides associated with mineralization fall into a narrow range of −3.0 to +2.6‰ with a mean of +0.1‰. The δ13CPDBvalues of dolomite and siderite from the Sawayaerdun gold deposit range from −5.4 to −0.6‰, possibly reflecting derivation of the carbonate carbon from a mixed magmatic/sedimentary source. Changes in physico‐chemical conditions and composition of the hydrothermal fluids, water–rock exchange and immiscibility of hydrothermal fluids are inferred to have played important roles in the ore‐forming process of the Sawayaerdun gold–antimony deposit.
Intestinal and hepatic metabolism of glutamine and citrulline in humans
Authors: Van De Poll Marcel C. G. , Ligthart‐Melis Gerdien C. , Boelens Petra G. , Deutz Nicolaas E. P. , Van Leeuwen Paul A. M. , Dejong Cornelis H. C.
Published: March 2007

Glutamine plays an important role in nitrogen homeostasis and intestinal substrate supply. It has been suggested that glutamine is a precursor for arginine through an intestinal–renal pathway involving inter‐organ transport of citrulline. The importance of intestinal glutamine metabolism for endogenous arginine synthesis in humans, however, has remained unaddressed. The aim of this study was to investigate the intestinal conversion of glutamine to citrulline and the effect of the liver on splanchnic citrulline metabolism in humans. Eight patients undergoing upper gastrointestinal surgery received a primed continuous intravenous infusion of [2‐15N]glutamine and [ureido‐13C–2H2]citrulline. Arterial, portal venous and hepatic venous blood were sampled and portal and hepatic blood flows were measured. Organ specific amino acid uptake (disposal), production and net balance, as well as whole body rates of plasma appearance were calculated according to established methods. The intestines consumed glutamine at a rate that was dependent on glutamine supply. Approximately 13% of glutamine taken up by the intestines was converted to citrulline. Quantitatively glutamine was the only important precursor for intestinal citrulline release. Both glutamine and citrulline were consumed and produced by the liver, but net hepatic flux of both amino acids was not significantly different from zero. Plasma glutamine was the precursor of 80% of plasma citrulline and plasma citrulline in turn was the precursor of 10% of plasma arginine. In conclusion, glutamine is an important precursor for the synthesis of arginine after intestinal conversion to citrulline in humans.
Auto‐inhibition of rat parallel fibre–Purkinje cell synapses by activity‐dependent adenosine release
Authors: Wall Mark J. , Dale Nicholas
Published: March 2007

Adenosine is an important signalling molecule involved in a large number of physiological functions. In the brain these processes are as diverse as sleep, memory, locomotion and neuroprotection during episodes of ischaemia and hypoxia. Although the actions of adenosine, through cell surface G‐protein‐coupled receptors, are well characterized, in many cases the sources of adenosine and mechanisms of release have not been defined. Here we demonstrate the activity‐dependent release of adenosine in the cerebellum using a combination of electrophysiology and biosensors. Short trains of electrical stimuli delivered to the molecular layerin vitro, release adenosine via a process that is both TTX and Ca2+sensitive. As ATP release cannot be detected, adenosine must either be released directly or rapidly produced by highly localized and efficient extracellular ATP breakdown. Since adenosine release can be modulated by receptors that act on parallel fibre–Purkinje cell synapses, we suggest that the parallel fibres release adenosine. This activity‐dependent adenosine release exerts feedback inhibition of parallel fibre–Purkinje cell transmission. Spike‐mediated adenosine release from parallel fibres will thus powerfully regulate cerebellar circuit output.
Inhibition of nitric oxide and prostaglandins, but not endothelial‐derived hyperpolarizing factors, reduces blood flow and aerobic energy turnover in the exercising human leg
Authors: Mortensen Stefan P. , González‐Alonso José , Damsgaard Rasmus , Saltin Bengt , Hellsten Ylva
Published: March 2007

Prostaglandins, nitric oxide (NO) and endothelial‐derived hyperpolarizing factors (EDHFs) are substances that have been proposed to be involved in the regulation of skeletal muscle blood flow during physical activity. We measured haemodynamics, plasma ATP and at rest and during one‐legged knee‐extensor exercise (19 ± 1 W) in nine healthy subjects with and without intra‐arterial infusion of indomethacin (Indo; 621 ± 17 μg min−1), Indo +NG‐monomethyl‐l‐arginine (l‐NMMA; 12.4 ± 0.3 mg min−1) (double blockade) and Indo +l‐NMMA + tetraethylammonium chloride (TEA; 12.4 ± 0.3 mg min−1) (triple blockade). Double and triple blockade lowered leg blood flow (LBF) at rest (P < 0.05), while it remained unchanged with Indo. During exercise, LBF and vascular conductance were 2.54 ± 0.10 l min−1 and 25 ± 1 mmHg, respectively, in control and they were lower with double (33 ± 3 and 36 ± 4%, respectively) and triple (26 ± 4 and 28 ± 3%, respectively) blockade (P < 0.05), while there was no difference with Indo. The lower LBF and vascular conductance with double and triple blockade occurred in parallel with a lower O2 delivery, cardiac output, heart rate and plasma [noradrenaline] (P < 0.05), while blood pressure remained unchanged and O2 extraction and femoral venous plasma [ATP] increased. Despite the increased O2 extraction, leg was 13 and 17% (triple and double blockade, respectively) lower than control in parallel to a lower femoral venous temperature and lactate release (P < 0.05). These results suggest that NO and prostaglandins play important roles in skeletal muscle blood flow regulation during moderate intensity exercise and that EDHFs do not compensate for the impaired formation of NO and prostaglandins. Moreover, inhibition of NO and prostaglandin formation is associated with a lower aerobic energy turnover and increased concentration of vasoactive ATP in plasma.
Sarcomere length dependence of rat skinned cardiac myocyte mechanical properties: dependence on myosin heavy chain
Authors: Korte F. Steven , McDonald Kerry S.
Published: March 2007

The effects of sarcomere length (SL) on sarcomeric loaded shortening velocity, power output and rates of force development were examined in rat skinned cardiac myocytes that contained either α‐myosin heavy chain (α‐MyHC) or β‐MyHC at 12 ± 1°C. When SL was decreased from 2.3 μm to 2.0 μm submaximal isometric force decreased ∼40% in both α‐MyHC and β‐MyHC myocytes while peak absolute power output decreased 55% in α‐MyHC myocytes and 70% in β‐MyHC myocytes. After normalization for the fall in force, peak power output decreased about twice as much in β‐MyHC as in α‐MyHC myocytes (41%versus 20%). To determine whether the fall in normalized power was due to the lower force levels, [Ca2+] was increased at short SL to match force at long SL. Surprisingly, this led to a 32% greater peak normalized power output at short SL compared to long SL in α‐MyHC myocytes, whereas in β‐MyHC myocytes peak normalized power output remained depressed at short SL. The role that interfilament spacing plays in determining SL dependence of power was tested by myocyte compression at short SL. Addition of 2% dextran at short SL decreased myocyte width and increased force to levels obtained at long SL, and increased peak normalized power output to values greater than at long SL in both α‐MyHC and β‐MyHC myocytes. The rate constant of force development (ktr) was also measured and was not different between long and short SL at the same [Ca2+] in α‐MyHC myocytes but was greater at short SL in β‐MyHC myocytes. At short SL with matched force by either dextran or [Ca2+], ktr was greater than at long SL in both α‐MyHC and β‐MyHC myocytes. Overall, these results are consistent with the idea that an intrinsic length component increases loaded crossbridge cycling rates at short SL and β‐MyHC myocytes exhibit a greater sarcomere length dependence of power output.
Mechanosensitive activation of K+ channel via phospholipase C‐induced depletion of phosphatidylinositol 4,5‐bisphosphate in B lymphocytes
Authors: Nam Joo Hyun , Lee Hoo‐Se , Nguyen Yen Hoang , Kang Tong Mook , Lee Sung Won , Kim Hye‐Young , Kim Sang Jeong , Earm Yung E. , Kim Sung Joon
Published: March 2007

In various types of cells mechanical stimulation of the plasma membrane activates phospholipase C (PLC). However, the regulation of ion channels via mechanosensitive degradation of phosphatidylinositol 4,5‐bisphosphate (PIP2) is not known yet. The mouse B cells express large conductance background K+ channels (LKbg) that are inhibited by PIP2. In inside‐out patch clamp studies, the application of MgATP (1 mm) also inhibited LKbg due to the generation of PIP2 by phosphoinositide (PI)‐kinases. In the presence of MgATP, membrane stretch induced by negative pipette pressure activated LKbg, which was antagonized by PIP2 (> 1 μm) or higher concentration of MgATP (5 mm). The inhibition by PIP2 was partially reversible. However, the application of methyl‐β‐cyclodextrin, a cholesterol scavenger disrupting lipid rafts, induced the full recovery of LKbg activity and facilitated the activation by stretch. In cell‐attached patches, LKbg were activated by hypotonic swelling of B cells as well as by negative pressure. The mechano‐activation of LKbg was blocked by U73122, a PLC inhibitor. Neither actin depolymerization nor the inhibition of lipid phosphatase blocked the mechanical effects. Direct stimulation of PLC by m‐3M3FBS or by cross‐linking IgM‐type B cell receptors activated LKbg. Western blot analysis and confocal microscopy showed that the hypotonic swelling of WEHI‐231 induces tyrosine phosphorylation of PLCγ2 and PIP2 hydrolysis of plasma membrane. The time dependence of PIP2 hydrolysis and LKbg activation were similar. The presence of LKbg and their stretch sensitivity were also proven in fresh isolated mice splenic B cells. From the above results, we propose a novel mechanism of stretch‐dependent ion channel activation, namely, that the degradation of PIP2 caused by stretch‐activated PLC releases LKbg from the tonic inhibition by PIP2.
The emergence of proteinase‐activated receptor‐2 as a novel target for the treatment of inflammation‐related CNS disorders
Authors: Bushell Trevor
Published: March 2007

The signalling molecules that are involved in inflammatory pathways are now thought to play a part in many disorders of the central nervous system (CNS). In common with peripheral chronic inflammatory diseases such a rheumatoid arthritis and ulcerative colitis, evidence now exists for the involvement of inflammatory cytokines, for example tumour necrosis factor (TNF) and interleukins (IL), in neurological disorders. A common factor observed with the up‐regulation of these cytokines in peripheral inflammatory diseases, is the increased expression of the proteinase‐activated receptor (PAR) subtype PAR‐2. Indeed, recent evidence suggests that targeting PAR‐2 helps reduce joint swelling observed in animal models of arthritis. So could targeting this receptor prove to be useful in treating those CNS disorders where inflammatory processes are thought to play an intrinsic role? The aim of this review is to summarize the emerging data regarding the role of PAR‐2 in neuroinflammation and ischaemic injury and discuss its potential as an exciting new target for the prevention and/or treatment of CNS disorders.