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Sansivero G, Galloway M, Dixon D. Abstract No. 149: Registered professional nurses placing central vascular access catheters via the internal jugular vein at the bedside: One year evaluation of a pilot program. J Vasc Interv Radiol 2010. [DOI: 10.1016/j.jvir.2009.12.305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Veit AC, Painter JT, Miller RA, Hardisty JF, Dixon D. Characterization of uterine granular cell tumors in B6C3F1 mice: a histomorphologic, immunohistochemical, and ultrastructural study. Vet Pathol 2008; 45:654-62. [PMID: 18725470 DOI: 10.1354/vp.45-5-654] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The granular cell tumor is most often a benign neoplasm of uncertain origin. Four uterine granular cell tumors in control and treated female B6C3F1 mice were identified in chronic studies at the National Toxicology Program. Two tumors occurred in untreated control animals and 2 in treated animals receiving different compounds. Tissue sections were evaluated histologically and stained with hematoxylin and eosin, periodic acid-Schiff with diastase resistance, Masson's trichrome, toluidine blue, phosphotungstic acid-hematoxylin, and stained immunohistochemically with a panel of antibodies to muscle (desmin, alpha smooth muscle actin), neural (S-100, neuron specific enolase), epithelial (wide-spectrum cytokeratin), and macrophage (F4/80) markers. The main histomorphologic feature of tumor cells was the presence of abundant cytoplasmic eosinophilic granules that stained positive for periodic acid-Schiff with diastase resistance. Tumors varied in appearance and were comprised of sheets and nests of round to polygonal cells with distinct borders. Nuclei were hyperchromatic, pleomorphic, and centrally to eccentrically located and often contained single nucleoli. Occasional multinucleated giant cells were observed. Tumors were pale pink and homogeneous with trichrome stain and negative with toluidine blue. Three tumors had positive to weakly positive immunoreactivity for desmin, and 1 was positive for alpha smooth muscle actin. Expression of S-100, wide-spectrum cytokeratin, and neuron-specific enolase was negative for all tumors. Ultrastructurally, prominent electron-dense cytoplasmic granules were abundant and contained secondary lysosomes with heterogeneous lysosomal contents. The characteristics of these uterine granular cell tumors were suggestive of a myogenic origin.
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Noonan W, Koch K, Nakane M, Ma J, Dixon D, Bolin A, Reinhart G. Differential effects of vitamin D receptor activators on aortic calcification and pulse wave velocity in uraemic rats. Nephrol Dial Transplant 2008; 23:3824-30. [DOI: 10.1093/ndt/gfn375] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Di X, Yu L, Moore AB, Castro L, Zheng X, Hermon T, Dixon D. A low concentration of genistein induces estrogen receptor-alpha and insulin-like growth factor-I receptor interactions and proliferation in uterine leiomyoma cells. Hum Reprod 2008; 23:1873-83. [PMID: 18492705 DOI: 10.1093/humrep/den087] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Previously, we found that genistein at low concentrations stimulates the growth of human uterine leiomyoma (LM) cells, but not uterine smooth muscle (myometrial) cells (SMC). The aim of this study was to understand the molecular mechanism whereby genistein causes hyperproliferation of LM cells. METHODS The effects of genistein at 1 microg/ml on LM cells and SMC were evaluated using estrogen response element gene reporter, real-time RT-PCR, western blot, immunoprecipitation and cell proliferation assays. RESULTS Elevated estrogen receptor (ER) transactivation, increased mRNA expression of early estrogen-responsive genes, progesterone receptor and insulin-like growth factor-I (IGF-I), and decreased protein levels of ER-alpha (ER alpha) were found in genistein-treated LM cells, but not SMC. Additionally, extracellular regulated kinase (ERK), Src homology/collagen (Shc) and ER alpha were transiently activated, and interactions between ER alpha and IGF-I receptor (IGF-IR) were rapidly induced by genistein in LM cells. Using ER antagonist ICI 182,780 and MAPK/ERK kinase (MEK) inhibitor PD98059, we found that these early events were inhibited and the proliferative effect of genistein on LM cells was abrogated. CONCLUSIONS ER alpha is involved in the transient activation of ERK/mitogen activated protein kinase (MAPK) by genistein via its early association with IGF-IR, leading to hyper-responsiveness of LM cells and confirming that ER signaling is enhanced by activation of ERK/MAPK in LM cells.
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Moore AB, Castro L, Yu L, Zheng X, Di X, Sifre MI, Kissling GE, Newbold RR, Bortner CD, Dixon D. Stimulatory and inhibitory effects of genistein on human uterine leiomyoma cell proliferation are influenced by the concentration. Hum Reprod 2007; 22:2623-31. [PMID: 17725991 PMCID: PMC2366995 DOI: 10.1093/humrep/dem185] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Due to dietary exposure of women to genistein, a soy-derived phytoestrogen, and the estrogen responsiveness of uterine leiomyomas 'fibroids', we evaluated the effects of genistein (0.001-50 microg/ml) on human uterine leiomyoma (UtLM) cells versus uterine smooth muscle cells (UtSMCs) in vitro. METHODS Light microscopy was used to determine the effects of genistein on cell morphology. Proliferation was assessed using a colorimetric assay and proliferating cell nuclear antigen (PCNA) immunocytochemistry. Flow cytometry was used to quantitate cells in the S-phase and those undergoing apoptosis. A fluorometric assay and confocal microscopy were used to detect caspase-3 activity and apoptotic bodies, respectively. RESULTS In UtLM cells, low concentrations (< or = 1 microg/ml) of genistein stimulated proliferation, increased PCNA labeling and the percentage of cells in the S-phase, but this did not occur in UtSMCs. Higher concentrations (> or = 10 microg/ml) of genistein adversely affected the morphology, significantly inhibited proliferation, decreased PCNA labeling, increased caspase-3 activity and induced apoptosis in both cell types. CONCLUSIONS Genistein's effects are concentration-dependent in both cell lines. Lower concentrations elicit proliferative effects on UtLM cells only; whereas, higher concentrations alter morphology, inhibit proliferation, and increase caspase activity and apoptosis in both cell types, with the latter two effects being more extensive in UtSMCs.
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Pekovic V, Kill I, Benham A, Dixon D, Edwards R, Bushby K, Foisner R, Hutchison C. The functional involvement of lamin A and LAPa in human ageing: the role for lamina protein redox modifications in senescence signaling. Comp Biochem Physiol A Mol Integr Physiol 2007. [DOI: 10.1016/j.cbpa.2007.01.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pekovic V, Kill I, Benham A, Dixon D, Edwards R, Bushby K, Foisner R, Hutchison C. The functional involvement of lamin A and LAPα in human ageing: The role for lamina protein redox modifications in senescence signaling. Comp Biochem Physiol A Mol Integr Physiol 2007. [DOI: 10.1016/j.cbpa.2007.01.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Dixon D, Brown A, Meenan BJ, Eatock J. Experiences of new product development in the medical device industry. MEDICAL DEVICE TECHNOLOGY 2006; 17:20-2. [PMID: 16736659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A survey of medical device professionals has revealed the factors that influence the development time and market success of new products. The vital elements that deliver commercial success are reported here.
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Aoyama H, Couse JF, Hewitt SC, Haseman JK, He H, Zheng X, Majstoravich S, Korach KS, Dixon D. Upregulation of estrogen receptor expression in the uterus of ovariectomized B6C3F1 mice and Ishikawa cells treated with bromoethane. Toxicol Appl Pharmacol 2006; 209:226-35. [PMID: 15922381 DOI: 10.1016/j.taap.2005.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Revised: 04/07/2005] [Accepted: 04/08/2005] [Indexed: 11/26/2022]
Abstract
In a 2-year NTP bioassay, Bromoethane (BE) was found to induce endometrial neoplasms in the uterus of B6C3F1 mice [; ]. In women, hormonal influences, such as "unopposed" estrogenic stimulus, have been implicated as important etiologic factors in uterine cancer. BE, however, does not affect the serum concentrations of sex hormones in female B6C3F1 mice [] and the mechanism of BE-induced uterine carcinogenesis still remains unclear. In the present study, we examined the estrogenic effects of BE on the uterus of ovariectomized B6C3F1 mice and on Ishikawa cells. Groups of 6 mice were given daily s.c. injections of 0, 100, 500 or 1000 mg BE/kg for 3 consecutive days. Mice treated with 17beta-estradiol served as positive controls. Mice were necropsied 24 h after the final injection, and uteri were weighed and examined histologically and immunohistochemically along with the vagina. Changes observed in the estrogen-treated mice included increased uterine weights, edema and inflammation of the endometrium, increased epithelial layers of the uterine and vaginal lumens and keratinization of the vaginal epithelium. In the BE-treated mice, no such changes occurred; however, immunohistochemical staining of the uterus revealed a significant increase in immunoexpression of the estrogen receptor alpha (ERalpha) in the two higher dose groups. Analysis of mRNA also showed slightly increased uterine ERalpha expression in these groups. Upregulated expression of ERalpha was confirmed in BE-treated Ishikawa cells, in which Western blotting analyses identified an intense signal at approximately 66 kDa, which is consistent with ERalpha. These data suggest that upregulated expression of ERalpha may be important in the induction of endometrial neoplasms in BE-treated mice.
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Swartz CD, Afshari CA, Yu L, Hall KE, Dixon D. Estrogen-induced changes in IGF-I, Myb family and MAP kinase pathway genes in human uterine leiomyoma and normal uterine smooth muscle cell lines. Mol Hum Reprod 2005; 11:441-50. [PMID: 15879465 DOI: 10.1093/molehr/gah174] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Many studies have implicated numerous hormones, growth factors, cytokines and other signal transduction molecules in the pathogenesis of uterine leiomyoma. Estrogen and estrogen-related genes are thought to play a key role in the growth of uterine leiomyomas, but the molecular mechanisms are unclear. In an attempt to investigate various pathways that might be involved in estrogen-regulated uterine leiomyoma growth as well as to identify any novel effector genes, microarray studies comparing estrogen-treated uterine leiomyoma cells (UtLM) and normal myometrial cells to untreated cells were performed. Several genes were differentially expressed in estrogen treated UtLM cells, including insulin-like growth factor-I (IGF-I) and others potentially involved in the IGF-I signalling pathway, specifically genes for A-myb, a transcription factor which promotes cell cycle progression and for MKP-1, a dual specificity phosphatase that dephosphorylates mitogen-activated protein kinase. IGF-I and A-myb were up-regulated in estrogen-treated cells while MKP-1 was down-regulated. Two other cell cycle promoting genes, c-fos and myc, were also down-regulated in estrogen treated UtLM cells. These genes are typically up-regulated in response to estrogen in some cells, notably breast epithelial cells, yet consistently have lower expression levels in uterine leiomyoma tissue when compared to autologous myometrium. Our results demonstrate some novel genes that may play a role in the growth of uterine leiomyoma, strengthen the case for involvement of the IGF-I pathway in the response of UtLM to estrogen and corroborate evidence that uterine smooth muscle cells respond to estrogen with a different gene expression pattern than that seen in epithelial cells.
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Dixon D, Goldberg R, Schneiderman N, Delamater A. Gender differences in TNF-alpha levels among obese vs nonobese Latino children. Eur J Clin Nutr 2004; 58:696-9. [PMID: 15042140 PMCID: PMC2776054 DOI: 10.1038/sj.ejcn.1601852] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To examine the relationships between TNF-alpha, obesity, and insulin resistance among prepubescent children. DESIGN Cross-sectional study. SETTING AND SUBJECTS Data were collected from 112 nondiabetic Latino schoolchildren from public schools in three South Florida communities. Of the enrolled participants, 43.8% were obese (BMI 95th percentile) and 51.8% presented with a family history of type 2 diabetes mellitus (T2DM). With one exception, all demonstrated normal glucose tolerance. INTERVENTIONS Plasma TNF-alpha levels were determined with enzyme-linked immunosorbance assay (ELISA). Homeostasis model assessment (HOMA-IR) was calculated as an index of insulin resistance. Mean levels of TNF-alpha among obese vs nonobese children were compared with a one-way analysis of variance with two groups, and the association between TNF-alpha and HOMA-IR was assessed with a Pearson's correlation. RESULTS Higher circulating TNF-alpha levels were revealed among nonobese vs obese children. Nonobese girls demonstrated higher TNF-alpha levels than obese girls, whereas there were no significant differences for boys. There were no significant differences after stratifying for family history of T2DM. There was a modest relationship between increased TNF-alpha levels and decreased insulin resistance. CONCLUSIONS The observed elevated circulating TNF-alpha concentrations among leaner participants may reflect an inflammatory process that has been associated with higher levels of physical fitness in both adults and prepubescent children. This effect may remain stronger for prepubescent girls, and the mechanism may be attenuated by the hormonal changes that occur with the onset of puberty.
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Menzin J, Lang K, Earle C, Foster T, Dixon D, Van Gool R. Treatment patterns and costs associated with acute myeloid leukemia in the elderly: A population-based analysis. J Clin Oncol 2004. [DOI: 10.1200/jco.2004.22.90140.6613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Hercule HC, Pamugo J, Dixon D, Oyekan AO. Interactions of the renin-angiotensin system and alpha-1 adrenoceptors on renal hemodynamics in healthy and acute renal failure rats: the role of nitric oxide. Blood Press 2003; 10:238-46. [PMID: 11800063 DOI: 10.1080/08037050152669765] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The renin-angiotensin (RAS) and the alpha1 sympathetic nervous system (SNS) interact at different levels in cardiovascular regulation. Concurrent use of angiotensin-converting enzyme (ACE) inhibitors and alpha1 receptor antagonists result in a synergistic antihypertensive action and is of wide utility in cardiovascular therapy. We examined the impact of concurrent inhibition of RAS (captopril or losartan) and the SNS (prazosin) before and after acute nitric oxide (NO) synthase inhibition with L-nitro-L-arginine methyl ester (L-NAME) on renal cortical perfusion (RCF) and blood pressure (MAP) in healthy and acute ischemic renal failure (ARF) rats (n = 6). Captopril or losartan reduced MAP and increased RCF more in healthy (p < 0.001) and ARF rats (p < 0.02). Prazosin alone reduced both MAP and RCF (p < 0.001). The combination of prazosin with captopril or losartan caused an additive fall in MAP, and mitigated the fall in RCF. Captopril + prazosin caused a profound fall in RCF following L-NAME, in healthy but not ARF rats (p < 0.001). Acetylcholine (Ach), a vasodilator which stimulates endogenous NO production caused a profound paradoxical fall in RCF in ARF, but not in healthy rats (p < 0.001 ANOVA). These results indicate a significant interaction between angiotensin II and phenylephrine in renal vasomotion. It establishes that endogenous NO homeostatically opposes angiotensin II-alpha1-mediated renal vasoconstriction, and that the vasodilator role of NO is diminished in ARF. The paradoxical fall in RCF induced by Ach in ARF is speculated to result, at least in part, from the formation of peroxynitrite (ONOO-), which acts as a renal vasoconstrictor, following the combination of ischemia-generated super oxide anion (O-2), with endothelial NO released by Ach.
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Leark RA, Dixon D, Hoffman T, Huynh D. Fake bad test response bias effects on the test of variables of attention. Arch Clin Neuropsychol 2002. [DOI: 10.1093/arclin/17.4.335] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Mehta DV, Kim YS, Dixon D, Jetten AM. Characterization of the expression of the retinoid-related, testis-associated receptor (RTR) in trophoblasts. Placenta 2002; 23:281-7. [PMID: 11969338 DOI: 10.1053/plac.2001.0779] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Previous studies have provided evidence indicating that the nuclear orphan receptor RTR plays an important role during embryonic development and in spermatogenesis. In this study, we examine the expression of RTR in murine placenta and several human placental choriocarcinoma cell lines. Northern blot analysis showed high expression of RTR mRNA in placental tissue. In contrast to murine testis, which contains 7.4 and 2.3 kb transcripts, placental tissue expressed only the larger transcript. Examination of RTR expression in murine placental tissue by immunohistochemistry demonstrated the presence of RTR protein in the nuclei of giant trophoblasts and spongiotrophoblasts. RTR mRNA was also expressed in rat choriocarcinoma Rcho-1 cells and in the human placental choriocarcinoma cell lines BeWo, JAR, and JEG-3. In trophoblasts, RTR was co-expressed with the estrogen-related receptors ERR alpha and ERR beta. Giant trophoblast differentiation in Rcho-1 cells, characterized by induction of placental lactogen I (PL-I), was accompanied by a steady decrease in the expression of RTR mRNA and down-regulation of ERR beta expression while levels of ERR alpha mRNA did not change significantly. RTR was able to inhibit ERR alpha-mediated transactivation through the consensus RTR-response element (RTRE) likely by competing with ERR alpha for binding to the RTRE. These results suggest the possibility of cross-talk between RTR and ERR alpha receptor signalling pathways in trophoblasts.
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MESH Headings
- Animals
- Cell Differentiation
- Cell Line
- Choriocarcinoma/genetics
- Choriocarcinoma/metabolism
- DNA-Binding Proteins
- Female
- Gene Expression
- Humans
- Immunohistochemistry
- Male
- Mice
- Nuclear Receptor Subfamily 6, Group A, Member 1
- Pregnancy
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Receptor Cross-Talk
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Estrogen/genetics
- Receptors, Estrogen/metabolism
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/metabolism
- Testis/metabolism
- Trophoblasts/cytology
- Trophoblasts/metabolism
- Uterine Neoplasms/genetics
- Uterine Neoplasms/metabolism
- ERRalpha Estrogen-Related Receptor
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Dixon D, Martin P, Harkin-Jones E. The Effect of Material Factors on the Density and Cell Morphology of Chemically Foamed Polypropylene. CELLULAR POLYMERS 2001. [DOI: 10.1177/026248930102000603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This paper assesses the effect of various material factors on the cell morphology and density of extruded expanded polypropylene (EPP), rod samples produced using a range of commercial chemical blowing agents (CBAs). This work is part of a research project into the optimisation of the extrusion and subsequent thermoforming of EPP sheet for food packaging applications. In each case the agents were added to PP and extruded under identical processing conditions, and the resulting variations in foam density and cell morphology are reported and discussed. Trials were also carried out to quantify the effects on the foam of additives, such as pigment, sodium benzoate, co-polymer and regrind, and the grade of polymer used (nucleated and un-nucleated). A design of experiment (DOE) methodology was adopted for all of these latter tests. The chemical blowing agents tested, produced foams with markedly different cellular structures with cell densities in the range 4.77×104 to 1.45×106 cells/cm3. Of the other material factors tested the change in polymer grade and the addition of sodium benzoate were found to most significantly affect the density and cell morphology.
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Combs D, Gouvier W, Dixon D. The role of attention in affect perception: an examination of Mirsky's four-factor model of attention in chronic schizophrenia. Arch Clin Neuropsychol 2001. [DOI: 10.1093/arclin/16.8.801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Couse JF, Dixon D, Yates M, Moore AB, Ma L, Maas R, Korach KS. Estrogen receptor-alpha knockout mice exhibit resistance to the developmental effects of neonatal diethylstilbestrol exposure on the female reproductive tract. Dev Biol 2001; 238:224-38. [PMID: 11784006 DOI: 10.1006/dbio.2001.0413] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Data indicate that estrogen-dependent and -independent pathways are involved in the teratogenic/carcinogenic syndrome that follows developmental exposure to 17beta-estradiol or diethylstilbestrol (DES), a synthetic estrogen. However, the exact role and extent to which each pathway contributes to the resulting pathology remain unknown. We employed the alphaERKO mouse, which lacks estrogen receptor-alpha (ERalpha), to discern the role of ERalpha and estrogen signaling in mediating the effects of neonatal DES exposure. The alphaERKO provides the potential to expose DES actions mediated by the second known ER, ERbeta, and those that are ER-independent. Wild-type and alphaERKO females were treated with vehicle or DES (2 microg/pup/day for Days 1-5) and terminated after 5 days and 2, 4, 8, 12, and 20 months for biochemical and histomorphological analyses. Assays for uterine expression of the genes Hoxa10, Hoxa11, and Wnt7a shortly after treatment indicated significant decreases in DES-treated wild-type but no effect in the alphaERKO. In contrast, the DES effect on uterine expression of Wnt4 and Wnt5a was preserved in both genotypes, suggesting a developmental role for ERbeta. Adult alphaERKO mice exhibited complete resistance to the chronic effects of neonatal DES exposure exhibited in treated wild-type animals, including atrophy, decreased weight, smooth muscle disorganization, and epithelial squamous metaplasia in the uterus; proliferative lesions of the oviduct; and persistent vaginal cornification. Therefore, the lack of DES effects on gene expression and tissue differentiation in the alphaERKO provides unequivocal evidence of an obligatory role for ERalpha in mediating the detrimental actions of neonatal DES exposure in the murine reproductive tract.
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Gerdom LE, Dixon D, Dipalma JA. Hemorrhoids, genital warts, and other perianal complaints. JAAPA 2001; 14:37-9, 43-4, 47. [PMID: 11599281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Bolto B, Dixon D, Eldridge R, King S. Cationic polymer and clay or metal oxide combinations for natural organic matter removal. WATER RESEARCH 2001; 35:2669-2676. [PMID: 11456166 DOI: 10.1016/s0043-1354(00)00552-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effect of adding suspended matter in the form of clay or metal oxide when a cationic polymer was employed as the primary coagulant was found to be beneficial. The solids provide both an adsorbent for natural organic matter (NOM) and a nucleating species for precipitating the NOM-polymer complex. Metal oxides in conjunction with a cationic polymer were more promising than clay, with effectiveness in the order Fe2O3 > Fe3O4 > Al2O3 > MnO2. Magnesium oxide at a much lower dose was nearly as effective as ferric oxide, but of course raised the pH level significantly. A simpler and more convenient way of having reactive solids present was to add alum to form flocs; for one of the waters studied the alum dose could be reduced by 67% by adding 1 mg/L of polymer, to give equal or better performance than alum alone at the optimum dose.
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Arai M, Billker O, Morris HR, Panico M, Delcroix M, Dixon D, Ley SV, Sinden RE. Both mosquito-derived xanthurenic acid and a host blood-derived factor regulate gametogenesis of Plasmodium in the midgut of the mosquito. Mol Biochem Parasitol 2001; 116:17-24. [PMID: 11463462 DOI: 10.1016/s0166-6851(01)00299-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Gametogenesis of Plasmodium in vitro can be induced by the combined stimulus of a 5 degrees C fall in temperature and the presence of xanthurenic acid (XA). In-vitro experiments showed that P. gallinaceum (EC(50)=80 nM) is much more sensitive to XA than P. berghei (9 microM), P. yoelii (8 microM), and P. falciparum (2 microM). However, in the mosquito vector, we do not know whether the temperature shift and XA are the only gametocyte-activating factors (GAF), nor do we know with certainty the true source(s) of XA in the mosquito blood meal. Previous studies indicate that XA is the only source of GAF in the mosquito. By defining, and then contrasting, the ability of an XA-deficient mutant of Aedes aegypti, with the wild-type mosquito to support exflagellation and ookinete formation in vivo, we determined the roles of parasite-, mosquito- and host blood-derived GAF in the regulation of gametogenesis of P. gallinaceum. Removal of both host and vector sources of GAF totally inhibited both exflagellation and ookinete production, whilst the lack of either single source resulted in only a partial reduction of exflagellation and ookinete formation in the mosquito gut. Both sources can be effectively replaced/substituted by synthetic XA. This suggests (1) both mosquito- and vertebrate-derived factors act as GAF in the mosquito gut in vivo; (2) the parasite itself is unable to produce any significant GAF activity. Studies are underway to determine whether vertebrate-derived GAF is XA. These data may form the basis of further studies of the development of new methods of interrupting malarial transmission.
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Rosengarten P, Kelly AM, Dixon D. Does routine use of the 15-lead ECG improve the diagnosis of acute myocardial infarction in patients with chest pain? EMERGENCY MEDICINE (FREMANTLE, W.A.) 2001; 13:190-3. [PMID: 11482857 DOI: 10.1046/j.1442-2026.2001.00210.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE It has been suggested that the use of additional electrocardiogram leads might improve the diagnostic sensitivity of this test, thus potentially expanding eligibility for thrombolysis for patients suffering myocardial infarction. The aims of this study were to evaluate the role of the 15-lead electrocardiogram in the emergency department chest pain population and to determine whether the routine use of the extra leads expands the group of patients eligible to receive thrombolysis. METHODS Blinded, individual and independent analysis by two emergency physicians of paired 12- and 15-lead electrocardiograms from adult patients with a primary complaint of chest pain. The main outcome measure was the diagnosis of myocardial infarction eligible for thrombolysis. Data were analysed using descriptive statistics and kappa statistics for agreement between raters. RESULTS 540 electrocardiograms (270 sets) were analysed. Myocardial infarction qualifying for thrombolysis was identified (by consensus) in 21 cases. In no case did the 15-lead electrocardiograph identify a myocardial infarction qualifying for thrombolysis that was not identified on the 12-lead electrocardiogram. CONCLUSION In this study, the 15-lead electrocardiogram did not increase the number of thrombolysis-eligible myocardial infarctions identified when compared with the 12-lead electrocardiogram. This study is limited by the small patient sample size, and a large multicentre trial is recommended to compare the 12- and 15-lead electrocardiograms in the emergency department population where the incidence of posterior and right-sided myocardial infarction is ultimately known.
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Dixon D. Children's magazines and science in the nineteenth century. VICTORIAN PERIODICALS REVIEW 2001; 34:228-238. [PMID: 18572490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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