2,273 research outputs found

    Be a ‘Do-Bee’: Take a Magic Mirror Journey Inside Romper Room

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    In the interest of adding to the general awareness and understanding of early educational television for children, this article explores a specific television program from the 1960s, Romper Room, chiefly via an interview with one of the show’s local hosts. This host – my mother Joyce Kramer – certainly had a magical job with new educational television, and it made her a celebrity in the town of Ottumwa, Iowa, in that time and for years afterward. I recall strangers calling to her from their passing vehicles if they spied her on a sidewalk, “Hi, Miss Joyce!” Impressive to my young mind as her celebrity was, it was only much later when I considered the impact the show had on young viewers both in our small town and, from other television areas, on the nation, as well as the impact on my mother’s later teaching. At this article’s basic function, eliciting her memories of the show helped to clarify how the show worked and why it was effective. Juxtaposed with her interview remarks are thoughts on the show in comparison with other educational television of the 1960s, the milieu of the times, and the legacy of the Romper Room on educational television for children in America

    Mechanisms Underlying Rapid Aldosterone Effects in the Kidney

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    The steroid hormone aldosterone is a key regulator of electrolyte transport in the kidney, and contributes to both homeostatic whole body electrolyte balance and also to the development of renal and cardiovascular pathologies. Aldosterone exerts its action principally through the mineralocorticoid receptor (MR), which acts as a ligand-dependent transcription factor in target tissues. Aldosterone also stimulates the activation of protein kinases and secondary messenger signaling cascades that act independently on specific molecular targets in the cell membrane and also modulate the transcriptional action of aldosterone through MR. This review describes current knowledge regarding the mechanisms and targets of rapid aldosterone action in the nephron, and how these responses are integrated into the regulation of renal physiology by aldosterone

    Cytosolic phospholipase A2 activation correlates with HER2 overexpression and mediates estrogen-dependent breast cancer cell growth.

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    Cytosolic phospholipase A(2)alpha (cPLA(2)alpha) catalyzes the hydrolysis of membrane glycerol-phospholipids to release arachidonic acid as the first step of the eicosanoid signaling pathway. This pathway contributes to proliferation in breast cancer, and numerous studies have demonstrated a crucial role of cyclooxygenase 2 and prostaglandin E(2) release in breast cancer progression. The role of cPLA(2)alpha activation is less clear, and we recently showed that 17beta-estradiol (E2) can rapidly activate cPLA(2)alpha in MCF-7 breast cancer cells. Overexpression or gene amplification of HER2 is found in approximately 30% of breast cancer patients and correlates with a poor clinical outcome and resistance to endocrine therapy. This study reports the first evidence for a correlation between cPLA(2)alpha enzymatic activity and overexpression of the HER2 receptor. The activation of cPLA(2)alpha in response to E2 treatment was biphasic with the first phase dependent on trans-activation through the matrix metalloproteinase-dependent release of heparin-bound epidermal growth factor. EGFR/HER2 heterodimerization resulted in downstream signaling through the ERK1/2 cascade to promote cPLA(2)alpha phosphorylation at Ser505. There was a correlation between HER2 and cPLA(2)alpha expression in six breast cancer cell lines examined, and inhibition of HER2 activation or expression in the SKBR3 cell line using herceptin or HER2-specific small interfering RNA, respectively, resulted in decreased activation and expression of cPLA(2)alpha. Pharmacological blockade of cPLA(2)alpha using a specific antagonist suppressed the growth of both MCF-7 and SKBR3 cells by reducing E2-induced proliferation and by stimulating cellular apoptosis and necrosis. This study highlights cPLAalpha(2) as a potential target for therapeutic intervention in endocrine-dependent and endocrine-independent breast cancer

    Non-genomic actions of aldosterone: From receptors and signals to membrane targets.

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    In tissues which express the mineralocorticoid receptor (MR), aldosterone modulates the expression of membrane targets such as the subunits of the epithelial Na(+) channel, in combination with important signalling intermediates such as serum and glucocorticoid-regulated kinase-1. In addition, the rapid \u27non-genomic\u27 activation of protein kinases and secondary messenger signalling cascades has also been detected in aldosterone-sensitive tissues of the nephron, distal colon and cardiovascular system. These rapid actions are variously described as being coupled to MR or to an as yet unidentified, membrane-associated aldosterone receptor. The rapidly activated signalling cascades add a level of fine-tuning to the activity of aldosterone-responsive membrane transporters and also modulate the aldosterone-induced changes in gene expression through receptor and transcription factor phosphorylation

    Aldosterone as a renal growth factor

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    Aldosterone regulates blood pressure through its effects on the cardiovascular system and kidney. Aldosterone can also contribute to the development of hypertension that leads to chronic pathologies such as nephropathy and renal fibrosis. Aldosterone directly modulates renal cell proliferation and differentiation as part of normal kidney development. The stimulation of rapidly activated protein kinase cascades is one facet of how aldosterone regulates renal cell growth. These cascades may also contribute to myofibroblastic transformation and cell proliferation observed in pathological conditions of the kidney. Polycystic kidney disease is a genetic disorder that is accelerated by hypertension. EGFR-dependent proliferation of the renal epithelium is a factor in cyst development and trans-activation of EGFR is a key feature in initiating aldosterone-induced signalling cascades. Delineating the components of aldosterone-induced signalling cascades may identify novel therapeutic targets for proliferative diseases of the kidney

    Self-Organizing: From Child’s Play to An Effective Wellness Program

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    This article examines the exercise practices of a group of faculty members at a regional university who for a decade have participated in their own racquetball league. These professors self-organized their exercise regimen and during the period of their participation have found significant benefits beyond the physical benefits, as a result. Through the production of reflective narratives focused on the impact of their racquetball participation, their self-reported data show two broad themes and numerous sub-themes that emerge from their exercise experience. They reveal significant health benefits, and they express more deeply the benefits of the positive social interaction that impacts many aspects of their personal and professional lives. The self-reported data from six players was requested and collected during a 6-week period. Faculty members were asked to write freely on the self-organizational aspects of their racquetball participation as well as their perceived benefits of this particular exercise. A qualitative textual analysis was applied to these narratives after they were coded for anonymity. Subsequent conclusions were drawn from the analyses of the content of each narrative

    Estrogen increases ENaC activity via PKCδ signaling in renal cortical collecting duct cells.

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    The most active estrogen, 17β-estradiol (E2), has previously been shown to stimulate a female sex-specific antisecretory response in the intestine. This effect is thought to contribute to the increase in whole body extracellular fluid (ECF) volume which occurs in high estrogen states, such as in the implantation window during estrous cycle. The increased ECF volume may be short-circuited by a renal compensation unless estrogen exerts a proabsorptive effect in the nephron. Thus, the effect of E2 on ENaC in kidney cortical collecting duct (CCD) cells is of interest to understand estrogen regulation of ECF volume. Previous studies showed a rapid stimulatory effect of estrogen on ENaC in bronchial epithelium. In this study we examined if such a rapid effect on Na(+) absorption could occur in the kidney. Experiments were carried out on murine M1-CCD cell cultures. E2 (25 nmol/L) treatment caused a rapid-onset (min) and sustained increase in the amiloride-sensitive Na(+) current (INa) in CCD monolayers mounted in Ussing chambers (control, 1.9 ± 0.2 μA/cm(2); E2, 4.7 ± 0.3 μA/cm(2); n = 43, P \u3c 0.001), without affecting the ouabain-sensitive Na(+)/K(+) pump current. The INa response to E2 was inhibited by PKCδ activity antagonism with rottlerin (5 μmol/L), inhibition of matrix metalloproteinases activity with GM6001 (1 μmol/L), inhibition of EGFR activity with AG1478 (10 μmol/L), inhibition of PLC activity with U-73122 (10 μmol/L), and inhibition of estrogen receptors with the general ER antagonist ICI-182780 (100 nmol/L). The estrogen activation of INa could be mimicked by the ERα agonist PPT (1 nmol/L). The nuclear excluded estrogen dendrimer conjugate (EDC) induced similar stimulatory effects on INa comparable to free E2. The end target for E2 stimulation of PKCδ was shown to be an increased abundance of the γ-ENaC subunit in the apical plasma membrane of CCD cells. We have demonstrated a novel rapid \u22nongenomic\u22 function of estrogen to stimulate ENaC via ERα-EGFR transactivation in kidney CCD cells. We propose that the salt-retaining effect of estrogen in the kidney together with its antisecretory action in the intestine are the molecular mechanisms causing the expanded ECF volume in high-estrogen states

    Genomic priming of the antisecretory response to estrogen in rat distal colon throughout the estrous cycle.

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    The secretion of Cl(-) across distal colonic crypt cells provides the driving force for the movement of fluid into the luminal space. 17beta-Estradiol (E2) produces a rapid and sustained reduction in secretion in females, which is dependent on the novel protein kinase C delta (PKC delta) isozyme and PKA isoform I targeting of KCNQ1 channels. This sexual dimorphism in the E2 response is associated with a higher expression level of PKC delta in female compared with the male tissue. The present study revealed the antisecretory response is regulated throughout the female reproductive (estrous) cycle and is primed by genomic regulation of the kinases. E2 (1-10 nm) decreased cAMP-dependent secretion in colonic epithelia during the estrus, metestrus, and diestrus stages. A weak inhibition of secretion was demonstrated in the proestrus stage. The expression levels of PKC delta and PKA fluctuated throughout the estrous cycle and correlated with the potency of the antisecretory effect of E2. The expression of PKC delta and PKA were up-regulated by estrogen at a transcriptional level via a PKC delta-MAPK-cAMP response element-binding protein-regulated pathway indicating a genomic priming of the antisecretory response. PK Cdelta was activated by the membrane-impermeant E2-BSA, and this response was inhibited by the estrogen receptor antagonist ICI 182,780. The 66-kDa estrogen receptor-alpha isoform was present at the plasma membrane of female colonic crypt cells with a lower abundance found in male colonic crypts. The study demonstrates estrogen regulation of intestinal secretion both at a rapid and transcriptional level, demonstrating an interdependent relationship between both nongenomic and genomic hormone responses

    Tamoxifen Suppresses the Growth of Malignant Pleural Mesothelioma Cells.

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    INTRODUCTION: Malignant pleural mesothelioma (MPM) is a rare but highly aggressive malignancy most often associated with exposure to asbestos. Recent evidence points to oestrogen receptor (ER)-β having a tumour-suppressor role in MPM progression, and this raises the question of whether selective modulators of ERs could play a role in augmenting MPM therapy. MATERIALS AND METHODS: We investigated the action of tamoxifen in inhibiting the growth and modulating the cisplatin sensitivity of four MPM cell lines. RESULTS: Tamoxifen inhibited the growth of MPM cells and also modulated their sensitivity to cisplatin. The MPM cell lines expressed ERβ, but the actions of tamoxifen were not blocked by antagonism of nuclear ERs. Tamoxifen treatment repressed the expression of cyclins by MPM cells, resulting in cell-cycle arrest and caspase-3-coupled apoptosis signaling. CONCLUSION: The ER-independent actions of tamoxifen on MPM cell proliferation and cell-cycle progression may have clinical benefits for a subset of patients with MPM

    Transcriptional Activation by NFκB Increases Perlecan/HSPG2 Expression in the Desmoplastic Prostate Tumor Microenvironment

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    Perlecan/HSPG2, a heparan sulfate proteoglycan typically found at tissue borders including those separating epithelia and connective tissue, increases near sites of invasion of primary prostatic tumors as previously shown for other proteins involved in desmoplastic tissue reaction. Studies of prostate cancer cells and stromal cells from both prostate and bone, the major site for prostate cancer metastasis, showed that cancer cells and a subset of stromal cells increased production of perlecan in response to cytokines present in the tumor microenvironment. In silico analysis of the HSPG2 promoter revealed two conserved NFκB binding sites, in addition to the previously reported SMAD3 binding sites. By systematically transfecting cells with a variety of reporter constructs including sequences up to 2.6 kb from the start site of transcription, we identified an active cis element in the distal region of the HSPG2 promoter, and showed that it functions in regulating transcription of HSPG2. Treatment with TNF-α and/or TGFβ1 identified TNF-α as a major cytokine regulator of perlecan production. TNF-α treatment also triggered p65 nuclear translocation and binding to the HSPG2 regulatory region in stromal cells and cancer cells. In addition to stromal induction of perlecan production in the prostate, we identified a matrix-secreting bone marrow stromal cell type that may represent the source for increases in perlecan in the metastatic bone marrow environment. These studies implicate perlecan in cytokine-mediated, innate tissue responses to cancer cell invasion, a process we suggest reflects a modified wound healing tissue response co-opted by prostate cancer cells
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