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A growing body of evidence suggests the interaction between arc magmas and crustal carbonates may play a large role in outgassed CO2 at arcs. We examine magma–carbonate interactions within the shallow (< 0.2 GPa) crust in the Jurassic Bonanza arc on Vancouver Island, a well-exposed island arc crustal section. Detailed mapping in the Merry Widow mountain area revealed unique, late-stage orbicular mafic dikes that only occur above the stratigraphic level of subsurface carbonates. The orbicular dikes are primitive, show physical and chemical evidence of interaction with limestone, including high CaO/SiO2 and low REE (~ 10–20× chondrite) that correlate with orbicule abundance, and are geochemically discordant from other rocks of the Bonanza arc. The orbicules have identical intergranular textures to the host melt but markedly higher Ca/Si. Simple binary mixing and MELTS modeling indicates the orbicular dike compositions are a mixture of a primitive hydrous arc basalt with 3–25% limestone addition. Comparisons to published experimental data on basalt–calcite reaction suggest some of the dike compositions result from > 25% calcite assimilation, producing up to 11 wt% CO2, orders of magnitude higher than the CO2 solubility of the parent melt (0.11 wt% CO2). We interpret the orbicules as Ca-rich hybrid melts produced from limestone assimilation that did not homogenize with the host dike magma and underwent crystallization during rapid ascent, possibly propelled by the excess CO2. Our results inform on the amount and mechanism of CO2 transport at low crustal pressures (< 0.5 GPa) in island arcs built on carbonate platforms. We estimate the CO2 flux of the Jurassic Bonanza arc to have ranged from 0.14 to > 1.16 Tg CO2/year during its ~ 34 Myr lifespan. [ABSTRACT FROM AUTHOR]

Purpose: Cancer registry survival analyses have shown that adolescent and young adult patients with low socioeconomic status (SES) have reduced survival compared to those with higher SES. The objective of this study was to determine whether neighborhood- (nSES) and/or individual-level SES (iSES) also predicted current quality of life in adolescent and young adult survivors. Methods: The Socioeconomics and Quality of Life study surveyed adolescent and young adult survivors of leukemia and lymphoma at least one year post-diagnosis using population-based ascertainment. Factor analysis was used to create a multidimensional age-relevant iSES score and compared with a preexisting census-block-group derived nSES score. Four quality of life domains were assessed: physical health, psychological and emotional well-being, social relationships, and life skills. Nested multivariable linear regression models were run to test the associations between both SES measures and quality of life and to compare the explanatory power of nSES and iSES. Results: Data from 110 individuals aged 16-40 were included in the final analysis. After adjustment for sociodemographic confounders, low nSES was associated only with poorer physical health, whereas low iSES was related to poorer quality of life in all four domains with iSES accounting for an additional 14, 12, 25, and 10 % of the variance, respectively. Conclusions: Measures of SES at the individual as compared to the neighborhood level may be stronger indicators of outcomes in adolescents and young adults, which has important implications for SES measurement in the context of cancer surveillance. [ABSTRACT FROM AUTHOR]

The discovery of long-lived epithelial stem cells in the bulge region of the hair follicle led to the hypothesis that epidermal renewal and epidermal repair after wounding both depend on these cells. To determine whether bulge cells are necessary for epidermal renewal, here we have ablated these cells by targeting them with a suicide gene encoding herpes simplex virus thymidine kinase (HSV-TK) using a Keratin 1–15 (Krt1-15) promoter. We show that ablation leads to complete loss of hair follicles but survival of the epidermis. Through fate-mapping experiments, we find that stem cells in the hair follicle bulge do not normally contribute cells to the epidermis which is organized into epidermal proliferative units, as previously predicted. After epidermal injury, however, cells from the bulge are recruited into the epidermis and migrate in a linear manner toward the center of the wound, ultimately forming a marked radial pattern. Notably, although the bulge-derived cells acquire an epidermal phenotype, most are eliminated from the epidermis over several weeks, indicating that bulge stem cells respond rapidly to epidermal wounding by generating short-lived 'transient amplifying' cells responsible for acute wound repair. Our findings have implications for both gene therapy and developing treatments for wounds because it will be necessary to consider epidermal and hair follicle stem cells as distinct populations. [ABSTRACT FROM AUTHOR]

The hair follicle bulge possesses putative epithelial stem cells. Characterization of these cells has been hampered by the inability to target bulge cells genetically. Here, we use a Keratin1-15 (Krt1-15, also known as K15) promoter to target mouse bulge cells with an inducible Cre recombinase construct or with the gene encoding enhanced green fluorescent protein (EGFP), which allow for lineage analysis and for isolation of the cells. We show that bulge cells in adult mice generate all epithelial cell types within the intact follicle and hair during normal hair follicle cycling. After isolation, adult Krt1-15-EGFP-positive cells reconstituted all components of the cutaneous epithelium and had a higher proliferative potential than Krt1-15-EGFP-negative cells. Genetic profiling of hair follicle stem cells revealed several known and unknown receptors and signaling pathways important for maintaining the stem cell phenotype. Ultimately, these findings provide potential targets for the treatment of hair loss and other disorders of skin and hair. [ABSTRACT FROM AUTHOR]

The herbivorous insects of tropical forests constitute some of the most diverse communities of living organisms. For this reason it has been difficult to discover the degree to which these communities are structured, and by what processes. Interspecific competition for resources does occur, but its contemporary importance is limited because most pairs of potentially competing insects feed on different host plants. An alternative way in which species can interact is through shared natural enemies, a process called apparent competition. Despite extensive theoretical discussion there are few field demonstrations of apparent competition, and none in hyper-diverse tropical communities. Here, we experimentally removed two species of herbivore from a community of leaf-mining insects in a tropical forest. We predicted that other species that share natural enemies with the two removed species would experience lower parasitism and have higher population densities in treatment compared with control sites. In both cases (on removal of a dipteran and a coleopteran leaf-miner species) we found significantly lower parasitism, and in one case (removal of the dipteran) we found significantly higher abundance a year after the manipulation. Our results suggest that apparent competition may be important in structuring tropical insect communities. [ABSTRACT FROM AUTHOR]

A chemically defined medium containing 1.2 m M Ca has been developed for the culture of primary epidermal keratinocytes from untreated adult mice such that proliferation is accompanied by the formation of desmosomes and stratification. Cultured cutaneous explants of 1 mm from the backs of untreated, control, and carcinogen-exposed mice all demonstrated epithelial outgrowth within 1 wk, and by 5 wk approached confluence with characteristics of terminal differentiation such as desmosomes and stratification. Addition of 12- O-tetradecanoylphorbol-13-acetate (TPA) to the medium in concentrations of 0.001, 0.01, and 0.1 µg/ml resulted in a delay of approximately 1 wk in the outgrowth of the explants compared with the acetone controls and in a 30% decrease in the diameter of the epithelial outgrowth at 3 wk. The inhibition in outgrowth was overcome at higher concentrations (0.5, 1.0, and 10 µg/ml TPA). No obvious differences in morphology or in the rate of epidermal outgrowth within a 5-wk interval among explants from normal untreated epidermis, epidermis from mice treated with acetone, or epidermis from mice treated with an initiating application of 7,12-dimethylbenz[ a]anthracene were observed. The defined composition of this medium and its ability to support reproducibly and conveniently both proliferation and differentiation of normal as well as treated primary adult murine epidermal cells suggest that it should be useful for a number of studies not previously possible that are relevent to the biology of the skin, to toxicology, and to carcinogenesis in the murine model system. [ABSTRACT FROM AUTHOR]

We used allogeneic bone marrow transplantation (BMT) and a mouse multistage cutaneous carcinogenesis model to probe recruitment of bone marrow-derived epithelial cells (BMDECs) in skin tumors initiated with the carcinogen, dimethylbenz[a]anthracene (DMBA), and promoted with 12-O-tetradecanolyphorbol-13-acetate (TPA). BMDECs clustered in the lesional epithelium, expressed cytokeratins, proliferated, and stratified. We detected cytokeratin induction in plastic-adherent bone marrow cells (BMCs) cultured in the presence of filter-separated keratinocytes (KCs) and bone morphogenetic protein 5 (BMP5). Lineage-depleted BMCs migrated towards High Mobility Group Box 1 (HMGB1) protein and epidermal KCs in ex vivo invasion assays. Naive female mice receiving BMTs from DMBA-treated donors developed benign and malignant lesions after TPA promotion alone. We conclude that BMDECs contribute to the development of papillomas and dysplasia, demonstrating a systemic contribution to these lesions. Furthermore, carcinogen-exposed BMCs can initiate benign and malignant lesions upon tumor promotion. Ultimately, these findings may suggest targets for treatment of non-melanoma skin cancers. Bone marrow-derived epithelial cells can be recruited to sites of chronic inflammation. Here, the authors using allogenic bone marrow transplantation in a multistage murine cutaneous carcinogenesis model show that bone marrow-derived epithelial cells and hair follicle stem cells are recruited to cutaneous neoplasms during tumor promotion of carcinogen-exposed skin and bone marrow. [ABSTRACT FROM AUTHOR]