95 results on '"Murnane J"'
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2. Mice, men, mustards and methylated xanthines: the potential role of caffeine and related drugs in the sensitization of human tumours to alkylating agents
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Byfield, JE, Murnane, J, Ward, JF, Calabro-Jones, P, Lynch, M, and Kulhanian, F
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Biomedical and Clinical Sciences ,Oncology and Carcinogenesis ,Cancer ,Development of treatments and therapeutic interventions ,5.1 Pharmaceuticals ,Alkylating Agents ,Animals ,Caffeine ,Cell Survival ,Cells ,Cultured ,Cyclophosphamide ,DNA Repair ,DNA Replication ,DNA ,Neoplasm ,HeLa Cells ,Humans ,Melphalan ,Mice ,Neoplasms ,Experimental ,Rats ,Ultraviolet Rays ,Xanthines ,Hela Cells ,Public Health and Health Services ,Oncology & Carcinogenesis ,Oncology and carcinogenesis - Abstract
The relationships between DNA damage from UV radiation, alkylating drugs and the methylated xanthines (MX) have been studied in normal and malignant rodent and human cells. A comparison of the level of DNA excision repair (repair replication and unscheduled DNA synthesis) confirms that some forms of alkylating-agent damage (probably mono-filar DNA adducts) are less completely removed by both normal and malignant rodent cells than by their human counterparts, rendering rodent cells more susceptible to the toxic potential of unexcised lesions. The toxicity of alkylating agents can be increased by the presence of several MXs during the period of DNA replication which follows infliction of the damage. Human cells appear capable of excising more DNA damage, rendering them somewhat less susceptible to enhancement of cytotoxicity by MX. This resistance of human cells is only quantitative, however, since 2 human cancer cell lines (HeLa and HT-29) could be sensitized to a variety of alkylating agents by appropriate concentrations of MX. Trimethylxanthine (caffeine) and the 2 clinically useful dimethylxanthines (theophylline and theobromine) appeared equally effective in sensitizing cells. The sensitization was dependent upon a slightly cytotoxic concentration of the MX and a suitably prolonged period of post-damage MX exposure. Of these 3 classic MXs, only theobromine might be clinically useful. The levels required for alkylating-agent sensitization exceed the clinically tolerable level of theophylline, and probably approach the tolerance of man to caffeine. The most likely mechanism by which MX sensitization is achieved is reversal of the inhibition of DNA replicon initiation which follows the infliction of significant DNA damage. Through the selection of suitable clinically useful alkylating agents (those dependent on active cellular transport for cell penetration) and appropriate MX scheduling, an enhanced therapeutic ratio might be achieved, potentially increasing the clinical usefulness of these alkylating agents. MX would thus form a useful class of agents adjuvant to conventional anti-cancer drugs. more...
- Published
- 1981
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3. Zeolite Combined with Alum and Polyaluminum Chloride Mixed with Agricultural Slurries Reduces Carbon Losses in Runoff from Grassed Soil Boxes.
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Murnane, J. G., Brennan, R. B., Fenton, O., and Healy, M. G.
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ZEOLITES ,SLURRY ,POLYALUMINUM chloride - Abstract
Carbon (C) losses from agricultural soils to surface waters can migrate through water treatment plants and result in the formation of disinfection by-products, which are potentially harmful to human health. This study aimed to quantify total organic carbon (TOC) and total inorganic C losses in runoff after application of dairy slurry, pig slurry, or milk house wash water (MWW) to land and to mitigate these losses through coamendment of the slurries with zeolite (2.36-3.35 mm clinoptilolite) and liquid polyaluminum chloride (PAC) (10% Al
2 O3 ) for dairy and pig slurries or liquid aluminum sulfate (alum) (8% Al2 O3 ) for MWW. Four treatments under repeated 30-min simulated rainfall events (9.6 mm h-1 ) were examined in a laboratory study using grassed soil runoff boxes (0.225 m wide, 1 m long; 10% slope): control soil, unamended slurries, PAC-amended dairy and pig slurries (13.3 and 11.7 kg t-1 , respectively), alum-amended MWW (3.2 kg t-1 ), combined zeolite and PAC-amended dairy (160 and 13.3 kg t-1 zeolite and PAC, respectively) and pig slurries (158 and 11.7 kg t-1 zeolite and PAC, respectively), and combined zeolite and alumamended MWW (72 and 3.2 kg t-1 zeolite and alum, respectively). The unamended and amended slurries were applied at net rates of 31, 34, and 50 t ha-1 for pig and dairy slurries and MWW, respectively. Significant reductions of TOC in runoff compared with unamended slurries were measured for PACamended dairy and pig slurries (52 and 56%, respectively) but not for alum-amended MWW. Dual zeolite and alum-amended MWW significantly reduced TOC in runoff compared with alum amendment only. We conclude that use of PAC-amended dairy and pig slurries and dual zeolite and alum-amended MWW, although effective, may not be economically viable to reduce TOC losses from organic slurries given the relatively low amounts of TOC measured in runoff from unamended slurries compared with the amounts applied. [ABSTRACT FROM AUTHOR] more...- Published
- 2016
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4. Use of Zeolite with Alum and Polyaluminum Chloride Amendments to Mitigate Runoff Losses of Phosphorus, Nitrogen, and Suspended Solids from Agricultural Wastes Applied to Grassed Soils.
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Murnane, J. G., Brennan, R. B., Healy, M. G., and Fenton, O.
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ZEOLITES ,ALUM ,POLYALUMINUM chloride ,AGRICULTURAL pollution ,AGRICULTURAL wastes - Abstract
Diffuse pollutant losses containing phosphorus (P), nitrogen (N), and suspended solids (SS) can occur when agricultural wastes are applied to soil. This study aimed to mitigate P, N, and SS losses in runoff from grassed soils, onto which three types of agricultural wastes (dairy slurry, pig slurry, and dairy-soiled water [DSW]), were applied by combining amendments of either zeolite and polyaluminum chloride (PAC) with dairy and pig slurries or zeolite and alum with DSW. Four treatments were investigated in rainfall simulation studies: (i) control soil, (ii) agricultural wastes, (iii) dairy and pig slurries amended with PAC and DSW amended with alum, and (iv) dairy and pig slurries amended with zeolite and PAC and DSW amended with zeolite and alum. Our data showed that combined amendments of zeolite and PAC applied to dairy and pig slurries reduced total P (TP) in runoff by 87 and 81%, respectively, compared with unamended slurries. A combined amendment of zeolite and alum applied to DSW reduced TP in runoff by 50% compared with unamended DSW. The corresponding reductions in total N (TN) were 56% for dairy slurry and 45% for both pig slurry and DSW. Use of combined amendments reduced SS in runoff by 73 and 44% for dairy and pig slurries and 25% for DSW compared with unamended controls, but these results were not significantly different from those using chemical amendments only. The findings of this study are that combined amendments of zeolite and either PAC or alum reduce TP and TN losses in runoff to a greater extent than the use of single PAC or alum amendments and are most effective when used with dairy slurry and pig slurry but less effective when used with DSW. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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5. Human fibroblasts expressing hTERT show remarkable karyotype stability even after exposure to ionizing radiation.
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Pirzio, L. M., Freulet-Marrière, M. -A., Bai, Y., Fouladi, B., Murnane, J. P., Sabatier, L., and Desmaze, C.
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FIBROBLASTS ,CONNECTIVE tissue cells ,CELLS ,KARYOTYPES ,CHROMOSOMES ,GENETICS ,IONIZING radiation ,RADIOACTIVITY - Abstract
Ectopic expression of telomerase results in an immortal phenotype in various types of normal cells, including primary human fibroblasts. In addition to its role in telomere lengthening, telomerase has now been found to have various functions, including the control of DNA repair, chromatin modification, and the control of expression of genes involved in cell cycle regulation. The investigations on the long-term effects of telomerase expression in normal human fibroblast highlighted that these cells show low frequencies of chromosomal aberrations. In this paper, we describe the karyotypic stability of human fibroblasts immortalized by expression of hTERT. The ectopic overexpression of telomerase is associated with unusual spontaneous as well as radiation-induced chromosome stability. In addition, we found that irradiation did not enhance plasmid integration in cells expressing hTERT, as has been reported for other cell types. Long-term studies illustrated that human fibroblasts immortalized by telomerase show an unusual stability for chromosomes and for plasmid integration sites, both with and without exposure to ionizing radiation. These results confirm a role for telomerase in genome stabilisation by a telomere-independent mechanism and point to the possibility for utilizing hTERT-immortalized normal human cells for the study of gene targeting. Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR] more...
- Published
- 2004
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6. Interstitial telomeric repeats are not preferentially involved in radiation-induced chromosome aberrations in human cells.
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Desmaze, C., Pirzio, L. M., Blaise, R., Mondello, C., Giulotto, E., Murnane, J. P., and Sabatier, L.
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TELOMERES ,CHROMOSOMES ,CHROMOSOMAL rearrangement ,GENETIC mutation ,RADIATION ,CELLS ,GENETICS ,CELL nuclei ,GENETIC transformation - Abstract
Telomeric repeat sequences, located at the end of eukaryotic chromosomes, have been detected at intrachromosomal locations in many species. Large blocks of telomeric sequences are located near the centromeres in hamster cells, and have been reported to break spontaneously or after exposure to ionizing radiation, leading to chromosome aberrations. In human cells, interstitial telomeric sequences (ITS) can be composed of short tracts of telomeric repeats (less than twenty), or of longer stretches of exact and degenerated hexanucleotides, mainly localized at subtelomeres. In this paper, we analyzed the radiation sensitivity of a naturally occurring short ITS localized in 2q31 and we found that this region is not a hot spot of radiation-induced chromosome breaks. We then selected a human cell line in which approximately 800 bp of telomeric DNA had been introduced by transfection into an internal euchromatic chromosomal region in chromosome 4q. In parallel, a cell line containing the plasmid without telomeric sequences was also analyzed. Both regions containing the transfected plasmids showed a higher frequency of radiation-induced breaks than expected, indicating that the instability of the regions containing the transfected sequences is not due to the presence of telomeric sequences. Taken together, our data show that ITS themselves do not enhance the formation of radiation-induced chromosome rearrangements in these human cell lines. Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR] more...
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- 2004
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7. The contribution of DNA ploidy to radiation sensitivity in human tumour cell lines.
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Schwartz, J.L., Murnane, J., and Weichselbaum, R.R.
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CANCER cells , *RADIATION , *CANCER treatment , *MEDICAL research - Abstract
The contribution of DNA ploidy to radiation sensitivity was investigated in a group of eight human tumour cell lines. As previous studies suggest, while more aneuploid tumours tend to be more radioresistant, there is no significant relationship between ploidy and radiation sensitivity (SF2). The failure to observe a significant effect of ploidy on radiation sensitivity is due to the complex and multifactorial basis of radiation sensitivity. When we determined the relationship between survival and radiation-induced chromosome aberration frequency, a measure independent of most other modifiers of sensitivity, we observed a direct relationship between ploidy and mean lethal aberration frequency. The mean lethal frequency of aberrations increased from about 1 for diploid cells to about 2 for tetraploid cells. The mean lethal frequency of aberrations was independent of DNA repair variations. These observations demonstrate that changes in DNA ploidy are an important contributor to radiation sensitivity variations in human tumour cell lines. Therefore, any battery of predictive assays should include DNA ploidy measurements. © 1999 Cancer Research Campaign [ABSTRACT FROM AUTHOR] more...
- Published
- 1999
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8. The influence of interstitial telomeric sequences on chromosome instability in human cells.
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Desmaze, C., Alberti, C., Martins, L., Pottier, G., Sprung, C. N., Murnane, J. P., and Sabatier, L.
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TELOMERES ,CHROMOSOMES ,PLASMIDS ,DNA ,IONIZING radiation ,CYTOGENETICS - Abstract
Although most telomere repeat sequences are found at the ends of chromosomes, some telomeric repeat sequences are also found at intrachromosomal locations in mammalian cells. Several studies have found that these interstitial telomeric repeat sequences can promote chromosome instability in rodent cells, either spontaneously or following ionizing radiation. In the present study we describe the extensive cytogenetic analysis of three different human cell lines with plasmids containing telomeric repeat sequences integrated at interstitial sites. In two of these cell lines, Q18 and P8SX, instability has been detected in the chromosome containing the integrated plasmid, involving breakage/fusion/bridge cycles or amplification of the plasmid DNA, respectively. However, the data suggest that the instability observed is characteristic of the general instability in these cell lines and that the telomeric repeat sequences themselves are not responsible. Consistent with this interpretation, the chromosome containing an integrated plasmid with 500 bp of telomeric repeat sequences is highly stable in the third cell line, SNG28, which has a relatively stable genome. The stability of the chromosome containing the integrated plasmid sequences in SNG28 makes this an excellent cell line to study the effect of ionizing radiation on the stability of interstitial telomeric sequences in human cells. [ABSTRACT FROM AUTHOR] more...
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- 1999
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9. Expression of the Candidate A-T Gene ATDC Is Not Detectable in a Human Cell Line with a Normal Response to Ionizing Radiation.
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Murnane, J. P., Zhu, Y., Young, B. R., and Christman, M. F.
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- 1994
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10. Targeting the Process of Mitotic Chromosome Segregation as a Novel Sensitizing Target to Radiation Treatment.
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Laughney, A., Murnane, J., Genovese, G., Elizalde, S., Compton, D., Kabeche, L., Spratt, D.E., Zaki, B., and Bakhoum, S.
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- *
MITOSIS , *CANCER radiotherapy , *CHROMOSOME segregation , *MEDICAL research , *ONCOLOGY - Published
- 2015
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11. The effect of lowering salt intake on blood pressure and biochemical indices of cardiovascular and bone health in adult subjects with slightly elevated blood pressure.
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Leenhardt, F., Arendt, E., Kerry, J., Kenny, S., Murnane, J., and Cashman, K. D.
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- 2011
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12. Nucleotide sequence analysis of a candidate gene for ataxia-telangiectasia group D (ATDC)
- Author
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Murnane, J [Univ. of California, San Francisco, CA (United States)]
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- 1994
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13. A Mitotic Pathway for Radiation-Induced Genome Damage.
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Bakhoum, S., Kabeche, L., Wood, M., Suriawinata, A., Louie, R., Chan, D., Petritsch, C., Murnane, J., Compton, D., and Zaki, B.
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- *
IONIZING radiation , *CANCER cell culture , *CHROMOSOME segregation , *CANCER radiotherapy , *BIOLOGICAL assay - Published
- 2013
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14. An Electronic Health Record-integrated Web Application Augments a QI-directed Morbidity & Mortality Conference and Improves Quality of Care.
- Author
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Sajankila N, Javens T, Hampl J, Coleman C, Murnane J, Kenney BD, and Besner GE
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- Humans, Morbidity, Internet, Congresses as Topic, Electronic Health Records, Quality Improvement
- Abstract
Background: In 2014, we developed a QI-directed Morbidity and Mortality (M&M) Conference, prioritizing discussion of individual and system failures, as well as development of action items to prevent failure recurrence. However, due to a reliance on individual electronic documents to store M&M data, our ability to assess trends in failures and action item implementation was hindered. To address this issue, in 2019, we created a secure electronic health record (EHR)-integrated web application (web app) to store M&M data., Study Design: In this study, we assessed the impact of our web app on efficient review and tracking of M&M data, including system failure occurrence and closure of action items. Additionally, in 2021, it was discovered that a backlog of action items existed. To address this issue, we implemented a QI initiative to reduce the backlog, and used the web app to compare action item closure over time., Results: Use of the web app dramatically improved review of M&M data. During the study period, there was a 67.0% reduction in the occurrence of the most common system failures. Additionally, our QI initiative resulted in a 97.7% reduction in the duration of time to complete a single action item and a 61.1% increase in the on-time closure rate for action items., Conclusions: Integration of a web app into a QI-directed M&M Conference enhanced our ability to track system level failures and action item closure over time. Using this web app, we demonstrated that our M&M Conference achieved its intended goal of improving the quality of patient care., Level of Evidence: IV., Competing Interests: Conflicts of interest None., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.) more...
- Published
- 2024
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15. Influence of sediment quality and microbial community on the functioning capacity of a constructed wetland treating alkaline leachate after 5.5 years in operation.
- Author
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Hudson A, Murnane JG, O'Dwyer T, Pawlett M, and Courtney R
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- Wetlands, Metals chemistry, Aluminum Oxide chemistry, Trace Elements, Microbiota
- Abstract
Constructed wetlands (CWs) have been demonstrated as a cost-effective alternative to chemical treatment systems for mine waters, with the microbial communities attributed to promoting carbonation and aiding pH neutralization. However, few data are available for the long-term use of CWs treating alkaline leachates nor the activity of microbes within them. To investigate the feasibility of CW to buffer alkaline pH, a pilot-scale wetland was implemented in 2015 to treat alkaline bauxite residue leachate. After 5.5 years, samples of supernatant water and sediment were taken at 0.5 m increments along the 11 m long wetland. Waters were analysed for pH, EC and metal(loid) content, while sediment was subjected to physico-chemical assessment and element fractionation. Microbial biomass and community were assessed by phospholipid fatty acid analysis (PLFA) and functionality by the Rapid Automated Bacterial Impedance Technique (RABIT). Evidence presented demonstrates that the CW operating for 66 months effectively treats bauxite residue leachate, with reduced influent pH from 11.5 to 7.8. Trace element analysis revealed effective reduction in Al (94.9 %), As (86.7 %) and V (57.6 %) with substrate analysis revealing a frontloading of elevated pH and trace element content in the first 5 m of the wetland. Sediment Al, As and V were present mostly (>94 % of total) in recalcitrant forms. Sediment Na was mostly soluble (48-62 %), but soils were not sodic (ESP < 15 %). Investigations into the microbial community revealed greatest biomass was in the first 5 m of the wetland, where pH, EC and metal contents were greatest. Microbial respiration using endemic Phragmites australis as a substrate demonstrates an ability to cycle recalcitrant carbon sources within a CW system. These novel microbial findings highlight the need for further investigation into the microbial communities in alkaline CWs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.) more...
- Published
- 2023
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16. Evaluating connectivity risk of farm roadway runoff with waters - Development and sensitivity analysis of a semi quantitative risk model.
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Rice P, Daly K, Tuohy P, Murnane JG, Nag R, and Fenton O
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- Farms
- Abstract
Farm roadways are an important sub-component of the nutrient transfer continuum (NTC) and roadway runoff (RR), leading to nutrient pressures in receiving waters at different times of the year at catchment scale. This study developed a semi-quantitative risk assessment model for dairy farms that once populated with data identifies roadway sections where RR enters waters. The model contains parameters that represent source, mobilisation and transport-connectivity stages of the NTC defined as continuous or categorical variables. Each parameter has a corresponding scoring system in terms of connectivity likelihood to waters (L) and the associated impact on water quality (I) from which field data can be converted to a risk score (RS). The connectivity or impact risk of any roadway section is a sum of all parameter scores, i.e. 'Total Risk Score' (TRS). The risk scores were classified into 5 categories (very low, low, moderate, high and very high). Field data from seven farms enabled five equal interval risk score classifications to be developed (very low (110-134), low (135-158), moderate (159-182), high (183-206), very high (207-230)). Fieldwork data showed differences between the number of mapped roadway sections ranging from 35 to 76, with the lowest and highest risk scores being 110 and 230, respectively. Out of all sections scored 25.9 %, 45.6 %, 20.4 %, 6.4 %, and 2 % were in very low, low, moderate, high and very high categories, respectively. In terms of management, only 8.4 % (i.e. high or very high scores) had all components of the NTC and required RR mitigation. An examination of the mobilisation parameter showed that the % of roadway sections needing mitigation is likely to increase if rainfall increases on these farms. An uncertainty assessment limiting the model to different levels of connectivity confirmed that all components of the NTC and those with greater than moderate risk should only be considered in future mitigation plans. Future work should concentrate on adapting this methodology to a wide range of farm enterprises., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.) more...
- Published
- 2022
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17. Coupling cognitive and brainstem dysfunction in multiple sclerosis-related chronic neuropathic limb pain.
- Author
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Foley P, Kong Y, Dirvanskiene R, Valdes-Hernandez M, Bastiani M, Murnane J, Sellar R, Roberts N, Pernet C, Weir C, Bak T, Colvin L, Chandran S, Fallon M, and Tracey I
- Abstract
Chronic pain in multiple sclerosis is common and difficult to treat. Its mechanisms remain incompletely understood. Dysfunction of the descending pain modulatory system is known to contribute to human chronic pain conditions. However, it is not clear how alterations in executive function influence this network, despite healthy volunteer studies linking function of the descending pain modulatory system, to cognition. In adults with multiple sclerosis-associated chronic neuropathic limb pain, compared to those without pain, we hypothesized altered functional connectivity of the descending pain modulatory system, coupled to executive dysfunction. Specifically we hypothesized reduced mental flexibility, because of potential importance in stimulus reappraisal. To investigate these hypotheses, we conducted a case-control cross-sectional study of 47 adults with relapsing remitting multiple sclerosis (31 with chronic neuropathic limb pain, 16 without pain), employing clinical, neuropsychological, structural, and functional MRI measures. We measured brain lesions and atrophy affecting descending pain modulatory system structures. Both cognitive and affective dysfunctions were confirmed in the chronic neuropathic limb pain group, including reduced mental flexibility (Delis Kaplan Executive Function System card sorting tests P < 0.001). Functional connectivity of rostral anterior cingulate and ventrolateral periaqueductal gray, key structures of the descending pain modulatory system, was significantly lower in the group experiencing chronic neuropathic pain. There was no significant between-group difference in whole-brain grey matter or lesion volumes, nor lesion volume affecting white matter tracts between rostral anterior cingulate and periaqueductal gray. Brainstem-specific lesion volume was higher in the chronic neuropathic limb pain group ( P = 0.0017). Differential functional connectivity remained after correction for brainstem-specific lesion volume. Gabapentinoid medications were more frequently used in the chronic pain group. We describe executive dysfunction in people with multiple sclerosis affected by chronic neuropathic pain, along with functional and structural MRI evidence compatible with dysfunction of the descending pain modulatory system. These findings extend understanding of close inter-relationships between cognition, function of the descending pain modulatory system, and chronic pain, both in multiple sclerosis and more generally in human chronic pain conditions. These findings could support application of pharmacological and cognitive interventions in chronic neuropathic pain associated with multiple sclerosis., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain.) more...
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- 2022
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18. Loss of TGFβ signaling increases alternative end-joining DNA repair that sensitizes to genotoxic therapies across cancer types.
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Liu Q, Palomero L, Moore J, Guix I, Espín R, Aytés A, Mao JH, Paulovich AG, Whiteaker JR, Ivey RG, Iliakis G, Luo D, Chalmers AJ, Murnane J, Pujana MA, and Barcellos-Hoff MH
- Subjects
- DNA Breaks, Double-Stranded, DNA Damage, DNA Repair genetics, Humans, Transforming Growth Factor beta, DNA End-Joining Repair, Neoplasms genetics
- Abstract
Among the pleotropic roles of transforming growth factor-β (TGFβ) signaling in cancer, its impact on genomic stability is least understood. Inhibition of TGFβ signaling increases use of alternative end joining (alt-EJ), an error-prone DNA repair process that typically functions as a "backup" pathway if double-strand break repair by homologous recombination or nonhomologous end joining is compromised. However, the consequences of this functional relationship on therapeutic vulnerability in human cancer remain unknown. Here, we show that TGFβ broadly controls the DNA damage response and suppresses alt-EJ genes that are associated with genomic instability. Mechanistically based TGFβ and alt-EJ gene expression signatures were anticorrelated in glioblastoma, squamous cell lung cancer, and serous ovarian cancer. Consistent with error-prone repair, more of the genome was altered in tumors classified as low TGFβ and high alt-EJ, and the corresponding patients had better outcomes. Pan-cancer analysis of solid neoplasms revealed that alt-EJ genes were coordinately expressed and anticorrelated with TGFβ competency in 16 of 17 cancer types tested. Moreover, regardless of cancer type, tumors classified as low TGFβ and high alt-EJ were characterized by an insertion-deletion mutation signature containing short microhomologies and were more sensitive to genotoxic therapy. Collectively, experimental studies revealed that loss or inhibition of TGFβ signaling compromises the DNA damage response, resulting in ineffective repair by alt-EJ. Translation of this mechanistic relationship into gene expression signatures identified a robust anticorrelation that predicts response to genotoxic therapies, thereby expanding the potential therapeutic scope of TGFβ biology., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.) more...
- Published
- 2021
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19. Soil phosphorus dynamics following land application of unsaturated and partially saturated red mud and water treatment residuals.
- Author
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Brennan RB, Murnane JG, Sharpley AN, Herron S, Brye KR, and Simmons T
- Subjects
- Fertilizers, Phosphorus, Soil, Soil Pollutants, Water Purification
- Abstract
The secondary use of P-sorbing industrial by-products as a fertilizer or soil conditioner is gaining increased attention, particularly in light of diminishing reserves of rock phosphate traditionally used to manufacture P fertilizer. This study examined applications of red mud (RM) and water treatment residuals (WTR) at two levels of P saturation (i.e. 'as received' and partially saturated) in a soil incubation and runoff plot study. When incubated with soils ranging in texture and initial P concentration, P-sorbing residuals that were less enriched with P decreased water-extractable soil P (WEP) concentration to a greater extent than more P saturated residuals. In contrast to WTR treatments, not all of the RM applications decreased soil WEP concentrations below those of the control soils. The runoff study investigated soil P dynamics when partially P-saturated RM and WTR's were surface applied to grass plots at 2 t ha
-1 on Day 0, followed by three rainfall simulations (7 cm h-1 for 30 min, Days 2, 7 and 28) and at 3 t ha-1 on Day 70 followed by two more rainfall simulations (Days 77 and 96). Application of residuals at these rates did not significantly increase dissolved reactive P (DRP) in runoff compared with unamended controls during the study. Forage cuttings taken 90 days after the first rainfall simulation indicated that nutrient uptake was not compromised by the application of the residuals. Overall results indicate that WTRs may be a more suitable soil amendment than RM residuals given their greater ability to reduce soil WEP across a range of soils without simultaneously increasing Mehlich-3 extractable soil P concentrations above the upper threshold limit (150 mg P kg-1 ), and their minimal impact on plant nutrient uptake., (Copyright © 2019 Elsevier Ltd. All rights reserved.) more...- Published
- 2019
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20. Misrepair in Context: TGFβ Regulation of DNA Repair.
- Author
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Liu Q, Lopez K, Murnane J, Humphrey T, and Barcellos-Hoff MH
- Abstract
Repair of DNA damage protects genomic integrity, which is key to tissue functional integrity. In cancer, the type and fidelity of DNA damage response is the fundamental basis for clinical response to cytotoxic therapy. Here we consider the contribution of transforming growth factor-beta (TGFβ), a ubiquitous, pleotropic cytokine that is abundant in the tumor microenvironment, to therapeutic response. The action of TGFβ is best illustrated in head and neck squamous cell carcinoma (HNSCC). Survival of HNSCC patients with human papilloma virus (HPV) positive cancer is more than double compared to those with HPV-negative HNSCC. Notably, HPV infection profoundly impairs TGFβ signaling. HPV blockade of TGFβ signaling, or pharmaceutical TGFβ inhibition that phenocopies HPV infection, shifts cancer cells from error-free homologous-recombination DNA double-strand-break (DSB) repair to error-prone alternative end-joining (altEJ). Cells using altEJ are more sensitive to standard of care radiotherapy and cisplatin, and are sensitized to PARP inhibitors. Hence, HPV-positive HNSCC is an experiment of nature that provides a strong rationale for the use of TGFβ inhibitors for optimal therapeutic combinations that improve patient outcome. more...
- Published
- 2019
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21. The use of brain functional magnetic resonance imaging to determine the mechanism of action of gabapentin in managing chronic pelvic pain in women: a pilot study.
- Author
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Seretny M, Murray SR, Whitaker L, Murnane J, Whalley H, Pernet C, and Horne AW
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- Adolescent, Adult, Brain Mapping, Chronic Pain drug therapy, Female, Humans, Magnetic Resonance Imaging, Middle Aged, Pain Measurement, Pilot Projects, Surveys and Questionnaires, Young Adult, Analgesics administration & dosage, Brain diagnostic imaging, Gabapentin administration & dosage, Pelvic Pain drug therapy
- Abstract
Objective: To inform feasibility and design of a future randomised controlled trial (RCT) using brain functional MRI (fMRI) to determine the mechanism of action of gabapentin in managing chronic pelvic pain (CPP) in women., Design: Mechanistic study embedded in pilot RCT., Setting: University Hospital., Participants: Twelve women (18-50 years) with CPP and no pelvic pathology (follow-up completed March 2014)., Intervention: Oral gabapentin (300-2700 mg) or matched placebo., Outcome Measures: After 12 weeks of treatment, participants underwent fMRI of the brain (Verio Siemens 3T MRI) during which noxious heat and punctate stimuli were delivered to the pelvis and arm. Outcome measures included pain (visual analogue scale), blood oxygen level dependent signal change and a semi-structured acceptability questionnaire at study completion prior to unblinding., Results: Full datasets were obtained for 11 participants. Following noxious heat to the abdomen, the gabapentin group (GG) had lower pain scores (Mean: 3.8 [SD 2.2]) than the placebo group (PG) (Mean: 5.8 [SD 0.9]). This was also the case for noxious heat to the arm with the GG having lower pain scores (Mean: 2.6 [SD 2.5]) than the PG (Mean: 6.2 [SD 1.1]). Seven out of 12 participants completed the acceptability questionnaire. 71% (five out of seven) described their participation in the fMRI study as positive; the remaining two rated it as a negative experience., Conclusions: Incorporating brain fMRI in a future RCT to determine the mechanism of action of gabapentin in managing CPP in women was feasible and acceptable to most women., Trial Registration Number: ISRCTN70960777., Competing Interests: Competing interests: The funders did not have any influence on the study design, data collection, analysis or interpretation of results., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY. Published by BMJ.) more...
- Published
- 2019
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22. Subjugation of TGFβ Signaling by Human Papilloma Virus in Head and Neck Squamous Cell Carcinoma Shifts DNA Repair from Homologous Recombination to Alternative End Joining.
- Author
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Liu Q, Ma L, Jones T, Palomero L, Pujana MA, Martinez-Ruiz H, Ha PK, Murnane J, Cuartas I, Seoane J, Baumann M, Linge A, and Barcellos-Hoff MH
- Subjects
- Animals, Cell Line, Tumor, Cell Survival, Disease Models, Animal, Flow Cytometry, Gene Expression Profiling, Gene Expression Regulation, Neoplastic, Humans, Mice, Squamous Cell Carcinoma of Head and Neck pathology, Xenograft Model Antitumor Assays, Papillomaviridae, Papillomavirus Infections complications, Papillomavirus Infections virology, Recombinational DNA Repair, Signal Transduction, Squamous Cell Carcinoma of Head and Neck etiology, Squamous Cell Carcinoma of Head and Neck metabolism, Transforming Growth Factor beta metabolism
- Abstract
Purpose: Following cytotoxic therapy, 70% of patients with human papillomavirus (HPV)-positive oropharyngeal head and neck squamous cell carcinoma (HNSCC) are alive at 5 years compared with 30% of those with similar HPV-negative cancer. Loss of TGFβ signaling is a poorly studied consequence of HPV that could contribute to patient outcome by compromising DNA repair., Experimental Design: Human HNSCC cell lines ( n = 9), patient-derived xenografts ( n = 9), tissue microarray ( n = 194), TCGA expression data ( n = 279), and primary tumor specimens ( n = 10) were used to define the relationship between TGFβ competency, response to DNA damage, and type of DNA repair., Results: Analysis of HNSCC specimens in situ and in vitro showed that HPV associated with loss of TGFβ signaling that increased response to radiation or cisplatin. TGFβ suppressed miR-182, which inhibited both BRCA1, necessary for homologous recombination repair (HRR), and FOXO3, required for ATM kinase activity. TGFβ signaling blockade by either HPV or inhibitors released miR182 control, compromised HRR and increased response to PARP inhibition. Antagonizing miR-182 rescued the HRR deficit in HPV-positive cells. Loss of TGFβ signaling unexpectedly increased repair by error prone, alternative end-joining (alt-EJ)., Conclusions: HPV-positive HNSCC cells are unresponsive to TGFβ. Abrogated TGFβ signaling compromises repair by HRR and increases reliance on alt-EJ, which provides a mechanistic basis for sensitivity to PARP inhibitors. The effect of HPV in HNSCC provides critical validation of TGFβ's role in DNA repair proficiency and further raises the translational potential of TGFβ inhibitors in cancer therapy., (©2018 American Association for Cancer Research.) more...
- Published
- 2018
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23. Impacts of zeolite, alum and polyaluminum chloride amendments mixed with agricultural wastes on soil column leachate, and CO 2 and CH 4 emissions.
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Murnane JG, Fenton O, and Healy MG
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- Agriculture, Alum Compounds, Animals, Carbon Dioxide, Nitrogen, Soil, Swine, Aluminum Hydroxide, Manure, Zeolites
- Abstract
This study aimed to quantify leaching losses of nitrogen (N), phosphorus (P) and carbon (C), as well as carbon dioxide (CO
2 ) and methane (CH4 ) emissions from stored slurry, and from packed soil columns surface applied with unamended and chemically amended dairy and pig slurries, and dairy soiled water (DSW). The amendments to the slurries, which were applied individually and together, were: polyaluminum chloride (PAC) and zeolite for pig and dairy slurry, and liquid aluminium sulfate (alum) and zeolite for DSW. Application of pig slurry resulted in the highest total nitrogen (TN) and nitrate-nitrogen (NO3 -N) fluxes (22 and 12 kg ha-1 ), whereas corresponding fluxes from dairy slurries and DSW were not significantly (p < 0.05) higher than those from the control soil. There were no significant (p < 0.05) differences in leachate N losses between unamended and amended dairy slurries, unamended and amended pig slurries, and unamended and amended DSW. There were no leachate P losses measured over the experimental duration. Total cumulative organic (TOC) and inorganic C (TIC) losses in leachate were highest for unamended dairy slurry (82 and 142 kg ha-1 ), and these were significantly (p < 0.05) reduced when amended with PAC (38 and 104 kg ha-1 ). The highest average cumulative CO2 emissions for all treatments were measured for pig slurries (680 kg CO2 -C ha-1 ) followed by DSW (515 kg CO2 -C ha-1 ) and dairy slurries (486 kg CO2 -C ha-1 ). The results indicate that pig slurry, either in raw or chemically amended form, poses the greatest environmental threat of leaching losses and gaseous emissions of CO2 and CH4 and, in general, amendment of wastewater with PAC, alum or zeolite, does not mitigate the risk of these losses., (Copyright © 2017 Elsevier Ltd. All rights reserved.) more...- Published
- 2018
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24. Assessment of intermittently loaded woodchip and sand filters to treat dairy soiled water.
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Murnane JG, Brennan RB, Healy MG, and Fenton O
- Subjects
- Animals, Cattle, Female, Silicon Dioxide, Soil, Water, Water Purification, Filtration, Waste Disposal, Fluid
- Abstract
Land application of dairy soiled water (DSW) is expensive relative to its nutrient replacement value. The use of aerobic filters is an effective alternative method of treatment and potentially allows the final effluent to be reused on the farm. Knowledge gaps exist concerning the optimal design and operation of filters for the treatment of DSW. To address this, 18 laboratory-scale filters, with depths of either 0.6 m or 1 m, were intermittently loaded with DSW over periods of up to 220 days to evaluate the impacts of depth (0.6 m versus 1 m), organic loading rates (OLRs) (50 versus 155 g COD m(-2) d(-1)), and media type (woodchip versus sand) on organic, nutrient and suspended solids (SS) removals. The study found that media depth was important in contaminant removal in woodchip filters. Reductions of 78% chemical oxygen demand (COD), 95% SS, 85% total nitrogen (TN), 82% ammonium-nitrogen (NH4N), 50% total phosphorus (TP), and 54% dissolved reactive phosphorus (DRP) were measured in 1 m deep woodchip filters, which was greater than the reductions in 0.6 m deep woodchip filters. Woodchip filters also performed optimally when loaded at a high OLR (155 g COD m(-2) d(-1)), although the removal mechanism was primarily physical (i.e. straining) as opposed to biological. When operated at the same OLR and when of the same depth, the sand filters had better COD removals (96%) than woodchip (74%), but there was no significant difference between them in the removal of SS and NH4N. However, the likelihood of clogging makes sand filters less desirable than woodchip filters. Using the optimal designs of both configurations, the filter area required per cow for a woodchip filter is more than four times less than for a sand filter. Therefore, this study found that woodchip filters are more economically and environmentally effective in the treatment of DSW than sand filters, and optimal performance may be achieved using woodchip filters with a depth of at least 1 m, operated at an OLR of 155 g COD m(-2) d(-1)., (Copyright © 2016 Elsevier Ltd. All rights reserved.) more...
- Published
- 2016
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25. Analysis of dose distribution and risk of pneumonitis in stereotactic body radiation therapy for centrally located lung tumors: a comparison of robotic radiosurgery, helical tomotherapy and volumetric modulated arc therapy.
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Kannarunimit D, Descovich M, Garcia A, Chen J, Weinberg V, Mcguinness C, Pinnaduwage D, Murnane J, Gottschalk AR, and Yom SS
- Subjects
- Aged, Female, Humans, Lung Neoplasms diagnostic imaging, Lung Neoplasms pathology, Male, Middle Aged, Neoplasm Staging, Organs at Risk, Radiometry, Radiotherapy Dosage, Radiotherapy Planning, Computer-Assisted, Radiotherapy, Image-Guided adverse effects, Radiotherapy, Intensity-Modulated adverse effects, Risk, Robotic Surgical Procedures, Tomography, Spiral Computed, Lung Neoplasms complications, Lung Neoplasms therapy, Radiation Pneumonitis epidemiology, Radiosurgery methods
- Abstract
Stereotactic body radiation therapy (SBRT) to central lung tumors is associated with normal -tissue toxicity. Highly conformal technologies may reduce the risk of complications. This study compares physical dose characteristics and anticipated risks of radiation pneumonitis (RP) among three SBRT modalities: robotic radiosurgery (RR), helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT). Nine patients with central lung tumors ≤5 cm were compared. RR, HT and VMAT plans were developed per RTOG 0831. Dosimetric comparisons included target coverage, conformity index, heterogeneity index, gradient index, maximal dose at 2 cm from target (D2 cm), and dose-volume parameters for organs at risk (OARs). Efficiency endpoints included total beam-on time and monitor units. RP risk was derived from Lyman-Kutcher-Burman modeling on in-house software. The average GTV and PTV were 11.6 ± 7.86 cm(3) and 36.8 ± 18.1 cm(3). All techniques resulted in similar target coverage (p = 0.64) and dose conformity (p = 0.88). While RR had sharper fall-off gradient (p = 0.002) and lower D2 cm (p = 0.02), HT and VMAT produced greater homogeneity (p < 0.001) and delivery efficiency (p = 0.001). RP risk predicted from whole or contralateral lung volumes was less than 10%, but was 2-3 times higher using ipsilateral volumes. Using whole (p = 0.04, p = 0.02) or ipsilateral (p = 0.004, p = 0.0008) volumes, RR and VMAT had a lower risk of RP than HT. Using contralateral volumes, RR had the lowest RP risk (p = 0.0002, p = 0.0003 versus HT, VMAT). RR, HT and VMAT were able to provide clinically acceptable plans following the guidelines provided by RTOG 0813. All techniques provided similar coverage and conformity. RR seemed to produce a lower RP risk for a scenario of small PTV-OAR overlap and small PTV. VMAT and HT produced greater homogeneity, potentially desirable for a large PTV-OAR overlap. VMAT probably yields the lowest RP risk for a large PTV. Understanding subtle differences among these technologies may assist in situations where multiple choices of modality are available., (© The Author(s) 2014.) more...
- Published
- 2015
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26. Decoding the fine-scale structure of a breast cancer genome and transcriptome.
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Volik S, Raphael BJ, Huang G, Stratton MR, Bignel G, Murnane J, Brebner JH, Bajsarowicz K, Paris PL, Tao Q, Kowbel D, Lapuk A, Shagin DA, Shagina IA, Gray JW, Cheng JF, de Jong PJ, Pevzner P, and Collins C more...
- Subjects
- Cell Line, Tumor, Chromosomes, Artificial, Bacterial metabolism, Chromosomes, Human, Female, Gene Expression Profiling methods, Genome, Human, Humans, In Situ Hybridization, Fluorescence, Molecular Sequence Data, Polymerase Chain Reaction, Reproducibility of Results, Breast Neoplasms genetics, Sequence Analysis, DNA methods, Transcription, Genetic
- Abstract
A comprehensive understanding of cancer is predicated upon knowledge of the structure of malignant genomes underlying its many variant forms and the molecular mechanisms giving rise to them. It is well established that solid tumor genomes accumulate a large number of genome rearrangements during tumorigenesis. End Sequence Profiling (ESP) maps and clones genome breakpoints associated with all types of genome rearrangements elucidating the structural organization of tumor genomes. Here we extend the ESP methodology in several directions using the breast cancer cell line MCF-7. First, targeted ESP is applied to multiple amplified loci, revealing a complex process of rearrangement and co-amplification in these regions reminiscent of breakage/fusion/bridge cycles. Second, genome breakpoints identified by ESP are confirmed using a combination of DNA sequencing and PCR. Third, in vitro functional studies assign biological function to a rearranged tumor BAC clone, demonstrating that it encodes anti-apoptotic activity. Finally, ESP is extended to the transcriptome identifying four novel fusion transcripts and providing evidence that expression of fusion genes may be common in tumors. These results demonstrate the distinct advantages of ESP including: (1) the ability to detect all types of rearrangements and copy number changes; (2) straightforward integration of ESP data with the annotated genome sequence; (3) immortalization of the genome; (4) ability to generate tumor-specific reagents for in vitro and in vivo functional studies. Given these properties, ESP could play an important role in a tumor genome project. more...
- Published
- 2006
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27. TP53-dependent chromosome instability is associated with transient reductions in telomere length in immortal telomerase-positive cell lines.
- Author
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Schwartz JL, Jordan R, Liber H, Murnane JP, and Evans HH
- Subjects
- Clone Cells, DNA Replication genetics, Gene Expression Regulation, Neoplastic genetics, Humans, Mutation, Telomerase metabolism, Tumor Cells, Cultured enzymology, Cell Line, Transformed enzymology, Chromosome Aberrations, Genes, p53 genetics, Telomerase biosynthesis, Telomere genetics
- Abstract
Telomere shortening in telomerase-negative somatic cells leads to the activation of the TP53 protein and the elimination of potentially unstable cells. We examined the effect of TP53 gene expression on both telomere metabolism and chromosome stability in immortal, telomerase-positive cell lines. Telomere length, telomerase activity, and chromosome instability were measured in multiple clones isolated from three related human B-lymphoblast cell lines that vary in TP53 expression; TK6 cells express wild-type TP53, WTK1 cells overexpress a mutant form of TP53, and NH32 cells express no TP53 protein. Clonal variations in both telomere length and chromosome stability were observed, and shorter telomeres were associated with higher levels of chromosome instability. The shortest telomeres were found in WTK1- and NH32-derived cells, and these cells had 5- to 10-fold higher levels of chromosome instability. The primary marker of instability was the presence of dicentric chromosomes. Aneuploidy and other stable chromosome alterations were also found in clones showing high levels of dicentrics. Polyploidy was found only in WTK1-derived cells. Both telomere length and chromosome instability fluctuated in the different cell populations with time in culture, presumably as unstable cells and cells with short telomeres were eliminated from the growing population. Our results suggest that transient reductions in telomere lengths may be common in immortal cell lines and that these alterations in telomere metabolism can have a profound effect on chromosome stability., (Copyright 2000 Wiley-Liss, Inc.) more...
- Published
- 2001
28. The relationship between spontaneous telomere loss and chromosome instability in a human tumor cell line.
- Author
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Fouladi B, Sabatier L, Miller D, Pottier G, and Murnane JP
- Subjects
- Base Sequence, Blotting, Southern, Chromosome Aberrations, DNA, Neoplasm analysis, Herpesvirus 1, Human genetics, Herpesvirus 1, Human metabolism, Humans, In Situ Hybridization, Fluorescence, Karyotyping, Mitosis, Molecular Sequence Data, Plasmids genetics, Sequence Homology, Nucleic Acid, Telomere chemistry, Thymidine Kinase genetics, Transfection, Tumor Cells, Cultured physiology, Chromosomes, Human genetics, Telomere genetics, Urinary Bladder Neoplasms genetics
- Abstract
Chromosome instability plays an important role in cancer by promoting the alterations in the genome required for tumor cell progression. The loss of telomeres that protect the ends of chromosomes and prevent chromosome fusion has been proposed as one mechanism for chromosome instability in cancer cells, however, there is little direct evidence to support this hypothesis. To investigate the relationship between spontaneous telomere loss and chromosome instability in human cancer cells, clones of the EJ-30 tumor cell line were isolated in which a herpes simplex virus thymidine kinase (HSV-tk) gene was integrated immediately adjacent to a telomere. Selection for HSV-tk-deficient cells with ganciclovir demonstrated a high rate of loss of the end these "marked" chromosomes (10-4 events/cell per generation). DNA sequence and cytogenetic analysis suggests that the loss of function of the HSV-tk gene most often involves telomere loss, sister chromatid fusion, and prolonged periods of chromosome instability. In some HSV-tk-deficient cells, telomeric repeat sequences were added on to the end of the truncated HSV-tk gene at a new location, whereas in others, no telomere was detected on the end of the marked chromosome. These results suggest that spontaneous telomere loss is a mechanism for chromosome instability in human cancer cells. more...
- Published
- 2000
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29. Document this...the important role providers play in today's managed care maze.
- Author
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Murnane J
- Subjects
- Ambulances, Emergency Medical Services economics, Humans, Insurance, Health, Reimbursement, Professional Competence, United States, Documentation standards, Emergency Medical Services organization & administration, Forms and Records Control standards, Managed Care Programs organization & administration
- Published
- 2000
30. Telomere instability in a human cancer cell line.
- Author
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Sprung CN, Afshar G, Chavez EA, Lansdorp P, Sabatier L, and Murnane JP
- Subjects
- Blotting, Southern, Carcinoma, Squamous Cell, Chromosome Aberrations genetics, Chromosome Disorders, DNA analysis, Humans, In Situ Hybridization, Fluorescence, Plasmids genetics, Repetitive Sequences, Nucleic Acid, Telomerase metabolism, Transfection, Tumor Cells, Cultured, Telomere genetics
- Abstract
Telomere maintenance is essential in immortal cancer cells to compensate for DNA lost from the ends of chromosomes, to prevent chromosome fusion, and to facilitate chromosome segregation. However, the high rate of fusion of chromosomes near telomeres, termed telomere association, in many cancer cell lines has led to the proposal that some cancer cells may not efficiently perform telomere maintenance. Deficient telomere maintenance could play an important role in cancer because telomere associations and nondisjunction have been demonstrated to be mechanisms for genomic instability. To investigate this possibility, we have analyzed the telomeres of the human squamous cell carcinoma cell line SQ-9G, which has telomere associations in approximately 75% of the cells in the population. The absence of detectable telomeric repeat sequences at the sites of these telomere associations suggests that they result from telomere loss. The analysis of telomere length by quantitative in situ hybridization demonstrated that, compared to the human squamous cell carcinoma cell line SCC-61 which has few telomere associations, SQ-9G has more extensive heterogeneity in telomere length and more telomeres without detectable telomeric repeat sequences. The dynamics of the changes in telomere length also demonstrated a higher rate of fluctuation in telomere length, both on individual telomeres and coordinately on all telomeres. These results demonstrate that telomere maintenance can play a role in the genomic instability seen in cancer cells. more...
- Published
- 1999
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31. A return on investment evaluation of the Citibank, N.A., health management program.
- Author
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Ozminkowski RJ, Dunn RL, Goetzel RZ, Cantor RI, Murnane J, and Harrison M
- Subjects
- Adolescent, Adult, Aged, Cost-Benefit Analysis, Female, Humans, Male, Middle Aged, Models, Econometric, North America, Regression Analysis, Health Expenditures, Health Promotion economics, Occupational Health Services economics, Risk Management economics
- Abstract
Objectives: Citibank, N.A., initiated a comprehensive health, demand, and disease management program in 1994, using program services offered by Healthtrac, Inc., of Menlo Park, California. Program components included an initial screening of employees, computerized triage of subjects into higher and lower risk intervention programs, extensive follow-up with the higher risk subjects, and general health education and awareness building. The objective of this study was to estimate the financial impact of this program on medical expenditures., Methods: A quasiexperimental design was applied comparing medical expenditures before vs. after the intervention for program participants and nonparticipants. The 22,838 subjects (11,194 program participants and 11,644 nonparticipants) were followed for an average of 38 months before and after administration of a Healthtrac health risk appraisal (HRA) instrument that triggered the start of the program. To adjust for selection bias to the extent possible with these data, multiple regression models were used to estimate the savings in medical expenditures associated with program participation. The resulting dollar savings were compared to program costs to estimate the economic return on the company's investment in the program., Results: The return on investment (ROI) was estimated to be between $4.56 and $4.73 saved per dollar spent on the program, depending on the discount rate applied. These results are similar to published evaluations of Healthtrac programs implemented with other populations., Conclusions: Despite limitations inherent in any retrospective observational study, the strong, positive ROI shown here suggests that a well-designed health management program (HMP), which focuses interventions on high risk populations, can result in monetary savings to an organization. more...
- Published
- 1999
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32. Characterization of a human gene with sequence homology to Saccharomyces cerevisiae SIR2.
- Author
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Afshar G and Murnane JP
- Subjects
- Amino Acid Sequence, Base Sequence, Cloning, Molecular, DNA Primers, Humans, Molecular Sequence Data, Sequence Homology, Amino Acid, Sirtuin 1, Sirtuin 2, Sirtuins, Tumor Cells, Cultured, DNA-Binding Proteins genetics, Fungal Proteins genetics, Histone Deacetylases, Saccharomyces cerevisiae genetics, Silent Information Regulator Proteins, Saccharomyces cerevisiae, Trans-Activators genetics
- Abstract
The proteins encoded by the SIR1, SIR2, SIR3 and SIR4 genes in yeast repress transcription at the mating type loci and telomeres. Among the SIR genes, SIR2 is the most evolutionarily conserved, and a number of genes with homology to SIR2 have been identified. In addition to transcriptional silencing, the product of SIR2 gene (Sir2p) has been shown to be involved in DNA repair and suppression of rDNA recombination. In the present study, the complete sequence of a human gene, SIR2L, with homology to the yeast SIR2 gene is presented. Comparison of the predicted sequence of the protein encoded by the SIR2L gene (SIR2Lp) with Sir2p or other proteins with homology to Sir2p reveals 20-33% overall identity and four highly conserved regions, the significance of which is unknown. SIR2L codes for a 2.1kb transcript which is expressed in various human tissues. The expression level of the transcript is found to be relatively high in the heart, brain and skeletal muscle tissues and low in lung and placenta. The intracellular location of SIR2Lp was visualized by fusion to the Green Fluorescent Protein or with a FLAG-tag. The results indicate that unlike Sir2p in yeast, SIR2Lp in human cells is found primarily in the cytoplasm. Using a mammalian inducible expression system, we also observed that unlike SIR2 in yeast, overexpression of SIR2L in human cancer cells has no effect on cell growth. Thus, although the human SIR2L gene appears to be related to the yeast SIR2 gene, it does not appear to have similar functions. more...
- Published
- 1999
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33. Chromosome healing in mouse embryonic stem cells.
- Author
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Sprung CN, Reynolds GE, Jasin M, and Murnane JP
- Subjects
- Animals, Mice, Chromosomes, DNA Repair, Stem Cells, Telomere chemistry
- Abstract
The addition of new telomeres to the ends of broken chromosomes, termed chromosome healing, has been extensively studied in unicellular organisms; however, its role in the mammalian cell response to double-strand breaks is unknown. A system for analysis of chromosome healing, which involves the integration of plasmid sequences immediately adjacent to a telomere, has been established in mouse embryonic stem cells. This "marked" telomere contains a neo gene for positive selection in G418, an I-SceI endonuclease recognition sequence for introducing double-strand breaks, and a herpes simplex virus thymidine kinase gene for negative selection with ganciclovir for cells that have lost the telomere. Transient expression of the I-SceI endonuclease results in terminal deletions involving telomeric repeat sequences added directly onto the end of the broken chromosome. The sites of addition of the new telomeres contain short regions of complementarity to telomeric repeat sequences. The most common site of addition is the last A of the ATAA 3' overhang generated by the I-SceI endonuclease, without the loss of a single nucleotide from the end of the chromosome. The next most frequent site involved 5 bp of complementarity, which occurred after the loss of four nucleotides from the end of the chromosome. The new telomeres are generally much shorter than in the parental cell line, and most increase in size with time in culture. These results demonstrate that chromosome healing is a mechanism for repair of chromosome breaks in mammalian cells. more...
- Published
- 1999
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34. Telomere dynamics in a human cancer cell line.
- Author
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Sprung CN, Sabatier L, and Murnane JP
- Subjects
- Carcinoma, Squamous Cell enzymology, Chromosomes, Human enzymology, Chromosomes, Human genetics, Clone Cells chemistry, Clone Cells enzymology, HeLa Cells, Humans, In Situ Hybridization, Fluorescence, Telomerase chemistry, Telomere enzymology, Tumor Cells, Cultured, Carcinoma, Squamous Cell chemistry, Carcinoma, Squamous Cell genetics, Telomere chemistry
- Abstract
Telomere maintenance is thought to be essential for immortalization of human cancer cells to compensate for the loss of DNA from the ends of chromosomes and to prevent chromosome fusion. We have investigated telomere dynamics in the telomerase-positive squamous cell carcinoma cell line SCC-61 by marking the ends of chromosomes with integrated plasmid sequences so that changes in the length of individual telomeres could be monitored. Despite having very short telomeres, SCC-61 has a relatively stable genome and few telomere associations. The marked telomeres in different SCC-61 clones have similar mean lengths which show little change with increasing time in culture. Thus, each marked telomere is maintained at a specific length, which we term the equilibrium mean length (EML). The Gaussian distribution in the length of the marked telomeres demonstrates that telomeres continuously fluctuate in length. Consistent with this observation, the mean lengths of the marked telomere in subclones of these cell lines initially differ, but then gradually return to the EML of the original clone with increasing time in culture. The analysis of a clone with two marked telomeres demonstrated that changes in telomere length can occur on each marked telomere independently or coordinately on both telomeres. These results suggest that the short telomeres in many tumor cell lines do not result from an inability to properly maintain telomeres at a specific length., (Copyright 1999 Academic Press.) more...
- Published
- 1999
- Full Text
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35. Comments on "Telomere-mediated chromosome healing" by P. Slijepcevic and P. E. Bryant (Radiat. Res. 148, 293, 1997)
- Author
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Murnane JP
- Subjects
- DNA Damage, DNA Repair, Humans, Chromosomes radiation effects, Telomere
- Published
- 1998
36. Immortalized cells with no detectable telomerase activity. A review.
- Author
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Reddel RR, Bryan TM, and Murnane JP
- Subjects
- Cell Cycle, Cell Line, Transformed, Cellular Senescence, Humans, Restriction Mapping, Telomerase analysis, Telomere genetics, Telomere ultrastructure, Tumor Cells, Cultured, Telomerase metabolism, Telomere physiology
- Abstract
Immortalization of human cells in culture is usually associated with expression of telomerase activity. In some cases, however, no telomerase activity is detectable even though comparison of the terminal restriction fragment (TRF) pattern before and after immortalization shows that lengthening of telomeres has occurred. The extreme heterogeneity in telomere length and the differences in the dynamics of telomere maintenance in telomerase-negative cell lines compared to telomerase-positive cell lines indicate that these cells have utilized one or more alternative mechanisms for lengthening of telomeres (ALT). All telomerase-negative immortalized cell lines examined to date show evidence of ALT activity, consistent with the hypothesis that telomere maintenance either by telomerase or by ALT is required for immortalization. The nature of the ALT mechanism(s) is currently unknown, but studies of telomere dynamics in an ALT cell line containing a marker just proximal to the telomeric sequences show gradual shortening of the telomere followed by rapid elongation. This is consistent with a non-reciprocal recombinational mechanism similar to that found in telomerase-defective mutant yeast strains. more...
- Published
- 1997
37. Normal telomere maintenance in immortal ataxia telangiectasia cell lines.
- Author
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Sprung CN, Bryan TM, Reddel RR, and Murnane JP
- Subjects
- Ataxia Telangiectasia genetics, Cell Line, Transformed, Humans, Lymphocytes, Telomerase metabolism, Ataxia Telangiectasia pathology, Telomere
- Abstract
Telomeres are maintained in germ line cells and immortal cell lines, but shorten with each cell division in most somatic cells. Blood lymphocytes from individuals with ataxia telangiectasia (AT) demonstrate an accelerated rate of telomere shortening and high levels of telomere associations. This accelerated loss of telomeres in somatic cells in AT could be due to either the loss of more telomeric DNA with every cell division or an increased rate of cell division. The gene for AT shares homology with the yeast TEL1 gene, in which mutations result in abnormally shortened telomeres. Thus, mutations in the gene for ataxia telangiectasia may also influence the ability of germ line cells and immortal cell lines to properly maintain telomere homeostasis. To investigate a possible defect of telomere maintenance in AT we have analyzed 8 simian virus 40 (SV40)-immortalized AT cell lines and twelve SV40-immortalized non-AT cell lines for both telomerase activity and telomere length. The results demonstrate that telomere length in AT cells is maintained via telomerase or an alternative (ALT) pathway in a manner indistinguishable from cell lines derived from normal cells. We also investigated telomere dynamics in one telomerase-positive AT cell line by analyzing the changes in the length of a single telomere, and found that this telomere maintained its equilibrium mean length (EML) similar to normal cell lines with stable chromosomes. The combined results show no significant differences between the telomeres of immortal AT and non-AT cell lines, demonstrating that the absence of wild-type ATM does not result in a fundamental defect in telomere maintenance in these cells. more...
- Published
- 1997
- Full Text
- View/download PDF
38. Effect of telomere length on telomeric gene expression.
- Author
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Sprung CN, Sabatier L, and Murnane JP
- Subjects
- Blotting, Southern, Cell Line, Transformed, Chromosomes, Human, Pair 13, Humans, Kanamycin Kinase, Phosphotransferases (Alcohol Group Acceptor) genetics, Plasmids, Simplexvirus enzymology, Simplexvirus genetics, Structure-Activity Relationship, Thymidine Kinase genetics, Transcription, Genetic, Gene Expression Regulation, Telomere physiology
- Abstract
Telomeres gradually shorten as human somatic cells divide and a correlation has been observed between the average telomere length and cell senescence. It has been proposed that the genes responsible for cell senescence are located near the telomere and are activated when telomere length reaches a critical point. This is consistent with evidence from Saccharomyces cerevisiae, in which genes are regulated differently depending on their distance from the telomere. We investigated the possibility that differential gene expression is conferred by telomere length in human cells. A plasmid containing the neomycin phosphotransferase (neo) gene was transfected into the SV40-transformed human fibroblast cell line LM217. In one transfectant the plasmid was integrated at the telomere of chromosome 13. Subclones of this cell line that had various lengths of telomeric repeat sequences on the end of this chromosome were isolated. No effect on neo gene expression was found when the length of the telomere varied between 25 and 0.5 kb, as demonstrated by colony forming ability, growth rates and RNA blot analysis. These results therefore suggest that putative chromatin structural differences conferred by telomere length do not affect the expression of genes located near telomeres. more...
- Published
- 1996
- Full Text
- View/download PDF
39. Role of induced genetic instability in the mutagenic effects of chemicals and radiation.
- Author
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Murnane JP
- Subjects
- Animals, Chromosome Aberrations, Genetic Diseases, Inborn genetics, Humans, Neoplasms genetics, Point Mutation, Alkylating Agents toxicity, Mutagenesis, Mutagens, Radiation, Ionizing
- Abstract
Recent studies have demonstrated that cells exposed to ionizing radiation or alkylating agents can develop prolonged genetic instability. Induced genetic instability is manifested in multiple ways, including delayed reproductive death, an increased rate of point mutations, and an increased rate of chromosome rearrangements. In many respects these changes are similar to the genetic instability associated with cancer and some human genetic diseases. Therefore, as with cancer cells, multiple mechanisms may be involved, some occurring in the early stages and some in the later stages. The high percentage of cells that develop induced genetic instability after exposure to stress, and the prolonged period over which the instability occurs, indicates that the instability is not in response to residual damage in the DNA or mutations in specific genes. Instead, changes affecting most of the exposed cells, such as epigenetic alterations in gene expression or chain reactions of chromosome rearrangements, are a more likely explanation. Learning more about the mechanisms involved in this process is essential for understanding the consequences of exposure of cells to ionizing radiation or alkylating agents. more...
- Published
- 1996
40. The product of the ataxia-telangiectasia group D complementing gene, ATDC, interacts with a protein kinase C substrate and inhibitor.
- Author
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Brzoska PM, Chen H, Zhu Y, Levin NA, Disatnik MH, Mochly-Rosen D, Murnane JP, and Christman MF
- Subjects
- Amino Acid Sequence, Animals, Ataxia Telangiectasia metabolism, Binding Sites, Breast Neoplasms, Cattle, Cell Line, Cell Line, Transformed, Cells, Cultured, Chromatography, Affinity, DNA-Binding Proteins genetics, DNA-Binding Proteins isolation & purification, Fibroblasts metabolism, Fibroblasts radiation effects, Genetic Complementation Test, Humans, Leucine Zippers, Molecular Sequence Data, Protein Kinase C antagonists & inhibitors, Protein Kinase C chemistry, Radiation, Ionizing, Sequence Homology, Amino Acid, Transcription Factors, Tumor Cells, Cultured, Vimentin chemistry, Zinc Fingers, Ataxia Telangiectasia genetics, DNA-Binding Proteins metabolism, Protein Kinase C metabolism, Vimentin metabolism
- Abstract
Ataxia-telangiectasia (AT) is an autosomal recessive human genetic disease characterized by immunological, neurological, and developmental defects and an increased risk of cancer. Cells from individuals with AT show sensitivity to ionizing radiation, elevated recombination, cell cycle abnormalities, and aberrant cytoskeletal organization. The molecular basis of the defect is unknown. A candidate AT gene (ATDC) was isolated on the basis of its ability to complement the ionizing radiation sensitivity of AT group D fibroblasts. Whether ATDC is mutated in any AT patients is not known. We have found that the ATDC protein physically interacts with the intermediate-filament protein vimentin, which is a protein kinase C substrate and colocalizing protein, and with an inhibitor of protein kinase C, hPKCI-1. Indirect immunofluorescence analysis of cultured cells transfected with a plasmid encoding an epitope-tagged ATDC protein localizes the protein to vimentin filaments. We suggest that the ATDC and hPKCI-1 proteins may be components of a signal transduction pathway that is induced by ionizing radiation and mediated by protein kinase C. more...
- Published
- 1995
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41. Use of a mammalian interspersed repetitive (MIR) element in the coding and processing sequences of mammalian genes.
- Author
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Murnane JP and Morales JF
- Subjects
- Alternative Splicing, Animals, Base Sequence, Biological Evolution, Consensus Sequence genetics, DNA genetics, DNA Transposable Elements genetics, Databases, Factual, Humans, Molecular Sequence Data, Poly A genetics, Receptors, Cholinergic genetics, Gene Expression Regulation genetics, Mammals genetics, Repetitive Sequences, Nucleic Acid genetics
- Abstract
The mammalian interspersed repetitive (MIR) element was amplified in mammals 130 million years ago. The MIR element is at least 260 bp in length and is found in approximately 105 copies in the mammalian genome. We analyzed copies of the MIR element in the DNA of various mammals to determine its relationship to the structure and function of genes, in an attempt to identify specific uses of the MIR element within the mammalian genome. We found that alternative splicing within the acetylcholine receptor gene in humans takes place within the MIR element and results in the incorporation of part of the MIR element into the coding sequence of this gene. Furthermore, the polyadenylation signal (AATAAA) at the 3' end of four different mammalian genes is derived from the MIR element. These uses of the MIR element suggest that other regulatory sequences found within the mammalian genome originated from ancient transposable elements, many of which may no longer be recognizable. more...
- Published
- 1995
- Full Text
- View/download PDF
42. Simian virus 40 transformation alters the actin cytoskeleton, expression of matrix metalloproteinases and inhibitors of metalloproteinases, and invasive behavior of normal and ataxia-telangiectasia human skin fibroblasts.
- Author
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Hansell EJ, Frisch SM, Tremble P, Murnane JP, and Werb Z
- Subjects
- Ataxia Telangiectasia enzymology, Cell Transformation, Neoplastic, Cells, Cultured, Collagenases biosynthesis, Cytoskeleton physiology, Fibroblasts cytology, Fibroblasts enzymology, Fibroblasts metabolism, Gene Expression, Glycoproteins biosynthesis, Humans, Matrix Metalloproteinase 3, Metalloendopeptidases antagonists & inhibitors, Protein Biosynthesis, Signal Transduction, Simian Immunodeficiency Virus, Skin cytology, Skin enzymology, Tissue Inhibitor of Metalloproteinase-2, Tissue Inhibitor of Metalloproteinases, Ataxia Telangiectasia metabolism, Cell Transformation, Viral, Metalloendopeptidases biosynthesis, Protease Inhibitors metabolism, Skin metabolism
- Abstract
Alterations in the actin cytoskeleton of normal cells result in changes in cell shape and adhesiveness and induce expression of matrix-degrading matrix metalloproteinases. We examined the effect of simian virus 40 transformation of normal and ataxia-telangiectasia human skin fibroblasts, a process that produces actin reorganization, altered cell morphology, and altered cell behavior, on expression of genes of the matrix metalloproteinase and tissue inhibitor of metalloproteinases gene families. Simian virus 40 transformation induced collagenase-1 gene expression; in contrast, stromelysin-1, 72-kDa gelatinase (gelatinase A), tissue inhibitor of metalloproteinases-1, and tissue inhibitor of metalloproteinases-2 genes were repressed. Transformation also altered the response of the fibroblasts to 12-O-tetradecanoylphorbol-13-acetate. Collagenase mRNA was induced in 12-O-tetradecanoylphorbol-13-acetate treated transformed cells up to 50-fold more than in untreated transformed cells or in 12-O-tetradecanoylphorbol-13-acetate treated untransformed parent cells. In contrast, 12-O-tetradecanoylphorbol-13-acetate did not overcome the attenuated expression of stromelysin-1 in the simian virus 40 transformants. In addition, 92-kDa gelatinase (gelatinase B) was induced by 12-O-tetradecanoylphorbol-13-acetate only in the simian virus 40 transformants. The responses of gelatinase A and tissue inhibitor of metalloproteinases-1 to 12-O-tetradecanoylphorbol-13-acetate were unchanged. The pattern of altered proteinase expression after transformation was accompanied by a phenotypic alteration in cell invasion. The simian virus 40 transformants exhibited enhanced invasiveness through a basement-membrane-like matrix. These data demonstrate that enhanced invasiveness in simian virus 40 transformed cells is accompanied by changes in actin organization and expression of proteinases and inhibitors, as well as in the balance between proteinases and inhibitors in favor of proteinases. more...
- Published
- 1995
- Full Text
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43. A role for genomic instability in cellular radioresistance?
- Author
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Morgan WF and Murnane JP
- Subjects
- Animals, Cell Cycle radiation effects, Cell Survival radiation effects, Cell Transformation, Neoplastic radiation effects, Chromosome Aberrations, DNA Damage genetics, DNA Damage physiology, DNA Repair genetics, DNA Repair physiology, Gene Expression Regulation, Neoplastic radiation effects, Genome, Human, Humans, Telomere genetics, Telomere radiation effects, Genome, Mutation, Neoplasms radiotherapy, Radiation Tolerance
- Abstract
Inherent cellular radioresistance plays a critical role in the failure of radiotherapy. Although the consequences of radioresistance are well known, the molecular, biological, and cellular bases of radioresistance remain a mystery. We propose that genomic instability, the increased rate of acquisition of alterations in the mammalian genome, can directly modulate cells' sensitivity to radiation. In particular, destabilization of chromosomes occurring as a consequence of genomic instability may result in enhanced 'plasticity of the genome'. This increased plasticity of the genome allows cells to better adapt to changes in local environment(s) during tumor progression, or improve cell survival following exposure to DNA damage encountered during radiotherapy protocols, thereby contributing to radioresistant cell populations found in tumors both before and after radiotherapy. more...
- Published
- 1995
- Full Text
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44. Cell cycle regulation in response to DNA damage in mammalian cells: a historical perspective.
- Author
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Murnane JP
- Subjects
- Animals, Apoptosis drug effects, Apoptosis genetics, Ataxia Telangiectasia genetics, Caffeine pharmacology, Cell Cycle Proteins genetics, DNA Repair genetics, Gene Expression Regulation, Humans, Mammals, Mutation, Tumor Suppressor Protein p53 deficiency, Tumor Suppressor Protein p53 genetics, Cell Cycle genetics, DNA Damage
- Abstract
Cell cycle delay has long been known to occur in mammalian cells after exposure to DNA-damaging agents. It has been hypothesized that the function of this delay is to provide additional time for repair of DNA before the cell enters critical periods of the cell cycle, such as DNA synthesis in S phase or chromosome condensation in G2 phase. Recent evidence that p53 protein is involved in the delay in G1 in response to ionizing radiation has heightened interest in the importance of cell cycle delay, because mutations in p53 are commonly found in human cancer cells. Because mammalian cells defective in p53 protein show increased genomic instability, it is tempting to speculate that the instability is due to increased chromosome damage resulting from the lack of a G1 delay. Although this appears at first glance to be a highly plausible explanation, a review of the research performed on cell cycle regulation and DNA damage in mammalian cells provides little evidence to support this hypothesis. Studies involving cells treated with caffeine, cells from humans with the genetic disease ataxia telangiectasia, and cells that are deficient in p53 show no correlation between G1 delay and increased cell killing or chromosome damage in response to ionizing radiation. Instead, G1 delay appears to be only one aspect of a complex cellular response to DNA damage that also includes delays in S phase and G2 phase, apoptosis and chromosome repair. The exact mechanism of the genomic instability associated with p53, and its relationship to the failure to repair DNA before progression through the cell cycle, remains to be determined. more...
- Published
- 1995
- Full Text
- View/download PDF
45. Telomere dynamics in an immortal human cell line.
- Author
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Murnane JP, Sabatier L, Marder BA, and Morgan WF
- Subjects
- Cell Line, Transformed, Humans, In Situ Hybridization, Fluorescence, Kinetics, Polymorphism, Genetic, Repetitive Sequences, Nucleic Acid, Telomere metabolism
- Abstract
The integration of transfected plasmid DNA at the telomere of chromosome 13 in an immortalized simian virus 40-transformed human cell line provided the first opportunity to study polymorphism in the number of telomeric repeat sequences on the end of a single chromosome. Three subclones of this cell line were selected for analysis: one with a long telomere on chromosome 13, one with a short telomere, and one with such extreme polymorphism that no distinct band was discernible. Further subcloning demonstrated that telomere polymorphism resulted from both gradual changes and rapid changes that sometimes involved many kilobases. The gradual changes were due to the shortening of telomeres at a rate similar to that reported for telomeres of somatic cells without telomerase, eventually resulting in the loss of nearly all of the telomere. However, telomeres were not generally lost completely, as shown by the absence of polymorphism in the subtelomeric plasmid sequences. Instead, telomeres that were less than a few hundred base pairs in length showed a rapid, highly heterogeneous increase in size. Rapid changes in telomere length also occurred on longer telomeres. The frequency of this type of change in telomere length varied among the subclones and correlated with chromosome fusion. Therefore, the rapid changes in telomere length appeared occasionally to result in the complete loss of telomeric repeat sequences. Rapid changes in telomere length have been associated with telomere loss and chromosome instability in yeast and could be responsible for the high rate of chromosome fusion observed in many human tumor cell lines. more...
- Published
- 1994
- Full Text
- View/download PDF
46. Formation of extrachromosomal circular DNA in HeLa cells by nonhomologous recombination.
- Author
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van Loon N, Miller D, and Murnane JP
- Subjects
- Base Sequence, Blotting, Southern, Cloning, Molecular, Genetic Complementation Test, HeLa Cells, Humans, Molecular Sequence Data, Polymerase Chain Reaction, DNA, Circular biosynthesis, Recombination, Genetic
- Abstract
Extrachromosomal circular DNA (eccDNA) generated from chromosomal DNA is found in all mammalian cells and increases with cell stress or aging. Studies of eccDNA structure and mode of formation provide insight into mechanisms of instability of the mammalian genome. Previous studies have suggested that eccDNA is generated through a process involving recombination between repetitive sequences. However, we observed that approximately one half of the small eccDNA fragments cloned from HeLa S3 cells were composed entirely of nonrepetitive or low-copy DNA sequences. We analyzed four of these fragments by polymerase chain reaction and nucleotide sequencing and found that they were complete eccDNAs. We then screened a human genomic library with the eccDNAs to isolate the complementary chromosomal sequences. Comparing the recombination junctions within the eccDNAs with the chromosomal sequences from which they were derived revealed that nonhomologous recombination was involved in their formation. One of the eccDNAs was composed of two separate sequences from different parts of the genome. These results suggest that rejoining of ends of fragmented DNA is responsible for the generation of a substantial portion of the eccDNAs found in HeLa S3 cells. more...
- Published
- 1994
- Full Text
- View/download PDF
47. Nucleotide sequence analysis of a candidate gene for ataxia-telangiectasia group D (ATDC).
- Author
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Leonhardt EA, Kapp LN, Young BR, and Murnane JP
- Subjects
- Amino Acid Sequence, Ataxia Telangiectasia classification, Base Sequence, Cosmids, DNA, Complementary genetics, Genetic Complementation Test, HeLa Cells, Humans, Molecular Sequence Data, Polymerase Chain Reaction, Transcription Factors, Ataxia Telangiectasia genetics, DNA-Binding Proteins genetics, Genes
- Abstract
A radioresistant cell clone (1B3) was previously isolated after transfection of an ataxia-telangiectasia (AT) group D cell line with a human cosmid library. A cosmid rescued from the integration site in 1B3 contained human DNA from chromosome position 11q23, the same region shown by both genetic linkage and chromosome transfer to contain the genes for AT complementation groups A/B, C, and D. A gene within the cosmid (ATDC) was found to produce mRNAs of different sizes. A cDNA for one of the most abundant mRNAs (3.0 kb) was isolated from a HeLa cell library. In the present study, we sequenced the 3.0-kb cDNA and the surrounding intron DNA in the cosmids. We used polymerase chain reaction, with primers in the introns, to confirm the number of exons and to analyze DNA from AT group D cells for mutations within this gene. Although no mutations were found, we do not rule out the possibility that mutations may be present within the regulatory sequences or coding sequences found in other mRNAs specific for this gene. From the sequence analysis, we found that the ATDC gene product is one of a group of proteins that share multiple zinc finger motifs and an adjacent leucine zipper motif. These proteins have been proposed to form homo- or heterodimers involved in nucleic acid binding, consistent with the fact that many of these proteins appear to be transcriptional regulatory factors involved in carcinogenesis and/or differentiation. The likelihood that the ATDC gene product is involved in transcriptional regulation could explain the pleiomorphic characteristics of AT, including abnormal cell cycle regulation. more...
- Published
- 1994
- Full Text
- View/download PDF
48. Cell checkpoint and radiosensitivity.
- Author
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Murnane JP and Schwartz JL
- Subjects
- Ataxia Telangiectasia pathology, Caffeine pharmacology, Cell Cycle drug effects, Cell Cycle physiology, Cell Cycle radiation effects, DNA Damage, G1 Phase, Humans, Radiation Tolerance, Tumor Suppressor Protein p53 physiology
- Published
- 1993
- Full Text
- View/download PDF
49. A radiation hybrid map of human chromosome 11q22-q23 containing the ataxia-telangiectasia disease locus.
- Author
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Richard CW 3rd, Cox DR, Kapp L, Murnane J, Cornelis F, Julier C, Lathrop GM, and James MR
- Subjects
- Animals, Base Sequence, Cell Line, Chromosome Mapping, Cricetinae, Fibroblasts radiation effects, Genetic Markers, Humans, Hybrid Cells ultrastructure, Likelihood Functions, Molecular Sequence Data, Ataxia Telangiectasia genetics, Chromosomes, Human, Pair 11 ultrastructure
- Abstract
We describe a high-resolution radiation hybrid map of human chromosome 11q22-q23 containing the ataxia-telangiectasia (AT) disease gene loci. The order and intermarker distances of 32 chromosome 11q22-q23 markers were determined by a multipoint maximum likelihood method of analysis of the cosegregation of markers in 100 radiation hybrids. The radiation hybrid map of polymorphic loci was consistent with genetic linkage maps of common markers. Several genes, including alpha B-crystallin, adrenal ferrodoxin, CBL2, collagenase, dopamine receptor type 2, neural cell adhesion molecule, progesterone receptor, and stromelysins 1 and 2, were placed in relation to previously ordered, genetically mapped polymorphic loci. Five new markers (alpha B-crystallin, adrenal ferrodoxin, CJ52.114, CJ52.3, and D11S535) were ordered within the current published flanking markers for the AT group A and group C disease loci. A candidate AT group D gene (ATDC) identified by Kapp et al. (1992, Am. J. Hum. Genet. 51: 45-54) was mapped telomeric to THY1, outside the flanking markers identified by multipoint linkage analysis for the major AT locus. more...
- Published
- 1993
- Full Text
- View/download PDF
50. A critical look at the association of human genetic syndromes with sensitivity to ionizing radiation.
- Author
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Murnane JP and Kapp LN
- Subjects
- Ataxia Telangiectasia genetics, DNA Repair physiology, Genes, Tumor Suppressor radiation effects, Genetic Diseases, Inborn etiology, Heterozygote, Humans, Neoplasms, Radiation-Induced genetics, Genetic Diseases, Inborn genetics, Radiation Tolerance genetics
- Abstract
Individuals with inherited heterozygosity for mutations involving tumor suppressor genes may be at greater risk for ionizing radiation-induced cancer even though their cells may not show increased cytotoxicity or chromosome damage. In addition, many human genetic syndromes have been reported to show increased sensitivity to ionizing radiation. In most instances the effects are small and/or not reproducible. Only in the genetic disease ataxia-telangiectasia (AT) is radiosensitivity consistently outside the normal range. Even AT heterozygotes (0.68 to 7.7% of the population) appear to be slightly radiosensitive, and their elevated cancer risk may result from exposure to ionizing radiation. Current research has concentrated on the isolation of the gene or genes responsible for this disease. more...
- Published
- 1993
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