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Taylor WC, Chan W, Cummings SS, Simons-Morton BG, Day RS, Sangi-Haghpeykar H, Pivarnik JS, Mueller WH, Detry MA, Wei II, Johnson-Masotti AP, Hsu HA. Healthy Growth: project description and baseline findings. Ethn Dis 2003; 12:567-77. [PMID: 12477144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023] Open
Abstract
OBJECTIVES The purpose of the study was to describe the physical activity, blood pressure, and body fat patterns of sixth-grade, African-American girls (N = 82), who participated in the Healthy Growth Study. The purpose of the primary study questions was to determine which sets of variables best predict blood pressure, physical activity, and body fat. DESIGN AND METHODS This paper is a cross sectional analysis of the first assessment of a 5-year longitudinal project. Standard procedures were used to assess height, weight, skinfolds, blood pressure, physical activity, predictors of physical activity, maturation, dietary intake, fitness level, and health behaviors. RESULTS The average age of the subjects was 12.3 years; almost two-thirds of the girls had reached menarche. Fifty-two percent of the 13-year-olds had body mass index (BMI) values greater than the 85th percentile for their age and sex compared to 32% of the 12-year-olds. None of the variables were significantly related to diastolic or systolic blood pressure. Physical activity was significantly and negatively related to total percent of calories from fat and to breast stages and positively related to waist/thigh ratio. Body mass index (BMI) was significantly and positively related to breast stages. CONCLUSIONS Important developmental differences between 12- and 1 3-year-olds were evident. Body mass index (BMI) was mainly dependent on physical maturity. No relationship was found between BMI and blood pressure. The relationship between physical activity and waist/thigh ratio merits further study. The importance of BMI and physical inactivity as potential indicators of cardiovascular risk in adolescent girls is discussed. Developmentally appropriate and culturally competent interventions are recommended to increase physical activity and healthy eating behaviors among adolescents.
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Hoelscher DM, Day RS, Kelder SH, Ward JL. Reproducibility and validity of the secondary level School-Based Nutrition Monitoring student questionnaire. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 2003; 103:186-94. [PMID: 12589324 DOI: 10.1053/jada.2003.50031] [Citation(s) in RCA: 193] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To evaluate the reproducibility and validity of the School-Based Nutrition Monitoring (SBNM) secondary level student questionnaire. DESIGN Reproducibility was evaluated using a test-retest study design by administering the questionnaire on the same day (morning and afternoon, n=254) and, when appropriate, 9 to 14 days apart (n=259). Validity was assessed by comparing foods selected on the questionnaire with foods reported from a single 24-hour recall covering the same referent period (yesterday) in 209 students. SUBJECTS/SETTING Eighth grade students in middle schools from central Texas were used: male and female, approximately 75% white, for the reproducibility study, with 15% Hispanic, 6% African American; for the validation study, approximately 38% white, 41% Hispanic, and 17% African American. STATISTICAL ANALYSIS Spearman rank order correlation, kappa statistic, and percentage agreement were used for both reproducibility and the validation. RESULTS For the reproducibility study, agreement for questions about food intake "yesterday" were 70% to 98%, with kappa statistics ranging from 0.54 to 0.93 and correlations between 0.66 and 0.97. Questions on recent physical activity had high agreement (66% to 89%) as did "usual" physical activity items, weight loss, and food selection behaviors. Nutrition knowledge items showed relatively weaker reliability: agreements ranged from 47% to 92%, with kappa statistics between 0.30 and 0.56. Attitude questions had weaker agreement (50% to 87%), kappa statistics (0.27 to 0.52), and correlations (0.33 to 0.63). For the validation study, correlation coefficients ranged from 0.32 for breads to 0.68 for milk and beans. Percentage agreement ranged from 38% for breads to 89% for gravy. APPLICATIONS/CONCLUSIONS Most questions on the SBNM secondary questionnaire were found to have acceptable reproducibility, whereas validation of food choice behaviors showed results similar to or better than other dietary assessment instruments for this age group. This questionnaire is a useful epidemiologic tool for surveillance, assessing broad intervention effects among groups or providing needs assessment data on selected nutrition and physical activity-related constructs.
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Lari SU, Day RS, Dobler K, Paterson MC. Initiation of strand incision at G:T and O(6)-methylguanine:T base mismatches in DNA by human cell extracts. Nucleic Acids Res 2001; 29:2409-17. [PMID: 11376160 PMCID: PMC55701 DOI: 10.1093/nar/29.11.2409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Extracts of the human glioma cell line A1235 (lacking O(6)-methylguanine-DNA methyltransferase) are known to restore a G:T mismatch to a normal G:C pair in a G:T-containing model (45 bp) DNA substrate. Herein we demonstrate that substitution of G:T with O(6)-methylguanine:T (m6G:T) results in extract-induced intra-strand incision in the DNA at an efficiency comparable to that of complete repair of the G:T-containing substrate, although the m6G:T mispair serves as a poor substrate for later repair steps (e.g. gap filling, as judged by defective DNA repair synthesis). The A1235 extract, when supplemented with ATP and the four normal dNTPs, incises 5' to the mismatched T, as inferred by the generation of a single-stranded 20mer fragment. Unlike its parental (A1235) counterpart, an extract of the alkylation-tolerant derivative cell line A1235-MR4 produces no 20mer fragment, even when thymine-DNA glycosylase (TDG) is added to the reaction mixture. In contrast, the A1235 extract, when augmented with TDG, catalyzes enhanced incision at m6G:T in the 45 bp DNA, yielding 5-10-fold greater 20mer than that of either extract or TDG alone. Interestingly, the absence of m6G:T incision activity in the A1235-MR4 extract is similar to that seen for extracts of several known mismatch repair-deficient cell lines of colon tumor origin. Together these results suggest that derivative A1235-MR4 cells are defective in m6G:T incision activity and that the efficiency of this activity in the parental (A1235) cells may depend on the presence of several ill-defined mismatch repair recognition proteins along with TDG and ATP.
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Day RS, Sun F, Cutler PH, King WF. Comparison of statistical and Lindgren conduction-core exchange approximations in a priori pseudopotential calculations for the lattice dynamics of metals. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0305-4608/7/7/001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Hmelo CE, Ramakrishnan S, Day RS, Shirey WE, Brufsky A, Johnson C, Baar J, Huang Q. Oncology thinking cap: scaffolded use of a simulation to learn clinical trial design. TEACHING AND LEARNING IN MEDICINE 2001; 13:183-191. [PMID: 11475662 DOI: 10.1207/s15328015tlm1303_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
BACKGROUND Physicians often are called on to participate in and interpret clinical trials, but their training in this area may not provide them with the inquiry skills that are needed. Simulations have the potential to be a promising tool for helping medical students learn the skills involved in clinical trial design. However, simulations may be complex and require additional scaffolding to support learning. DESCRIPTION The goal of this study was to teach aspects of cancer clinical trial design through the scaffolded use of a simulation, the Oncology Thinking Cap. The software-based scaffolding provided guidance in designing the trial. Subsequently, the simulation allowed students to run the designed trial, which produces detailed patient histories. This feedback then could be used to redesign the trial. EVALUATION Twenty-four 4th-year medical students were asked to design a clinical trial in advance, on paper, to test a new anticancer drug. Student groups then designed and simulated running the clinical trial assisted by the software environment. Instructional effectiveness was measured using a pretest-posttest design that included having students (a) write a group research proposal and (b) individually critique a flawed proposal. At the group level (N = 6 groups), students demonstrated a 34% increase in the number of elements of a clinical trial that they included in their research proposals. At the individual level (N = 24), students improved by 48% in their critiques of flawed proposals. CONCLUSIONS Scaffolding embedded in the simulator is a promising approach to helping students learn about clinical trial design.
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Zamboni WC, Egorin MJ, Van Echo DA, Day RS, Meisenberg BR, Brooks SE, Doyle LA, Nemieboka NN, Dobson JM, Tait NS, Tkaczuk KH. Pharmacokinetic and pharmacodynamic study of the combination of docetaxel and topotecan in patients with solid tumors. J Clin Oncol 2000; 18:3288-94. [PMID: 10986062 DOI: 10.1200/jco.2000.18.18.3288] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE The sequence in which chemotherapeutic agents are administered can alter their pharmacokinetics, therapeutic effect, and toxicity. We evaluated the pharmacokinetics and pharmacodynamics of docetaxel and topotecan when coadministered on two different sequences of administration. PATIENTS AND METHODS On cycle 1, docetaxel was administered as a 1-hour infusion at 60 mg/m(2) without filgrastim and at 60, 70, and 80 mg/m(2) with filgrastim on day 1, and topotecan was administered at 0.75 mg/m(2) as a 0.5-hour infusion on days 1 to 4. On cycle 2, topotecan was administered on days 1 to 4, and docetaxel was administered on day 4. Cycles were repeated every 21 days. Blood samples for high-performance liquid chromatography measurement of docetaxel (CL(DOC)) and topotecan (CL(TPT)) total clearance were obtained on day 1 of cycle 1 and day 4 of cycle 2. CL(DOC) and CL(TPT) were calculated using compartmental methods. RESULTS Mean +/- SD CL(DOC) in cycles 1 and 2 were 75.9 +/- 79.6 L/h/m(2) and 29.2 +/- 17.3 L/h/m(2), respectively (P: <.046). Mean +/- SD CL(TPT) in cycles 1 and 2 were 8.5 +/- 4.4 L/h/m(2) and 9.3 +/- 3.4 L/h/m(2), respectively (P: >. 05). Mean +/- SD neutrophil nadir in cycles 1 and 2 were 4,857 +/- 6, 738/microL and 2,808 +/- 4,518/microL, respectively (P: =.02). CONCLUSION Administration of topotecan on days 1 to 4 and docetaxel on day 4 resulted in an approximately 50% decrease in docetaxel clearance and was associated with increased neutropenia.
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Konety BR, Nguyen TS, Dhir R, Day RS, Becich MJ, Stadler WM, Getzenberg RH. Detection of bladder cancer using a novel nuclear matrix protein, BLCA-4. Clin Cancer Res 2000; 6:2618-25. [PMID: 10914702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
We have identified previously six nuclear matrix proteins (NMPs) that are bladder cancer specific. In this study, we analyzed the expression of one of these proteins, BLCA-4, in bladder tumors and normal bladder tissue. We also examined the appearance of BLCA-4 in the urine as a biomarker for bladder cancer. BLCA-4 was isolated from nuclear matrix preparations of bladder tumors, and its peptide sequence was determined. The antibodies generated against the resulting BLCA-4 peptides were then used to detect its presence in immunoblots and in urine samples by immunoassay. We analyzed tissue samples of bladder tumor and normal donor bladders and urine obtained from 51 normal individuals and 54 patients with pathologically confirmed bladder cancer. The BLCA-4 peptide sequences do not resemble any known human protein sequences. On immunoblot analysis, BLCA-4 expression was detectable in tumor and normal tissues from patients with bladder cancer but not in any of the normal bladder tissue obtained from organ donors. Using a prospectively determined cutoff level of 13 A (absorbance) units/microg protein, all 51 normal individuals tested were negative for BLCA-4 expression, whereas 53 of 55 samples from patients with bladder cancer were positive. These results suggest that BLCA-4 is present throughout the bladder in both the tumor and morphologically normal areas in bladder cancer patients. BLCA-4 is a very sensitive (96.4%) and specific (100%) marker for bladder cancer. BLCA-4 is a bladder cancer-specific marker that can be detected using a urine-based assay and can be used in the diagnosis of bladder cancer.
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Kirkwood JM, Mascari RA, Edington HD, Rabkin MS, Day RS, Whiteside TL, Vlock DR, Shipe-Spotloe JM. Analysis of therapeutic and immunologic effects of R(24) anti-GD3 monoclonal antibody in 37 patients with metastatic melanoma. Cancer 2000; 88:2693-702. [PMID: 10870051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
BACKGROUND Antitumor effects of antibodies against ganglioside antigens of melanoma have been reported, but neither optimal doses nor mechanisms have been established. METHODS This Phase IB trial of the murine immunoglobulin IgG(3) monoclonal antibody R(24) against disialoganglioside GD3 was conducted with 37 patients to define better the dose-response relation and mechanism of action of R(24) in patients with metastatic melanoma. RESULTS Dose-limiting toxicity consisted of a pulmonary capillary leak syndrome in 3 of 5 patients in the 80 mg/M(2)/day dosage tier. Serial blood and tumor biopsy samples were obtained prior to therapy and on Days 5, 9, and 22 following R(24) infusion. Tumor biopsy-infiltrating lymphocytes were enumerated in peritumoral, endotumoral, and perivascular compartments: endotumoral CD4(+) and CD8(+) T cells and HLA-DR(+) T cells increased over time on R(24) antibody. Endotumoral CD4 lymphoid infiltrate activation (DR expression) and antibody-dependent cytotoxicity were the greatest in the one patient who achieved a complete response. CONCLUSIONS Clinical response was associated with depression in natural killer (CD56(+) and CD56(+)DR(+)) blood cells (P = 0.03) and was associated with R(24) dosage (P = 0.01). A complete response that lasted 2 years and a partial response that lasted 2 months occurred at a dose of 1 mg/M(2)/day. The limited number of clinical responses observed in this trial hampered the correlation of antitumor and immune parameters but provided a rational foundation for the future evaluation of antiganglioside antibodies.
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Joe BN, Fukui MB, Meltzer CC, Huang QS, Day RS, Greer PJ, Bozik ME. Brain tumor volume measurement: comparison of manual and semiautomated methods. Radiology 1999; 212:811-6. [PMID: 10478251 DOI: 10.1148/radiology.212.3.r99se22811] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To compare the reliability of two approaches to measuring enhancing brain tumor volumes--the conventional manual trace method and a threshold-based, semiautomated computer software method. MATERIALS AND METHODS Two operators rated contrast material-enhanced, T1-weighted axial magnetic resonance (MR) image data sets from 16 patients aged 21-71 years with high-grade gliomas. Each MR data set was rated twice by using manual tracing and twice by using the semiautomated method. The semiautomated measurement method involved a thresholding algorithm based on mixture modeling. The data collection time for each method was recorded. Reliability was measured by using inter- and intraoperator agreement indexes. RESULTS Mean intraoperator agreement indexes (+/- SD) were 0.90 +/- 0.09 (operator 1) and 0.83 +/- 0.15 (operator 2) for the manual trace method and 0.83 +/- 0.17 (operator 1) and 0.84 +/- 0.16 (operator 2) for the semiautomated measurement method. The mean interoperator agreement was 0.85 +/- 0.14 for the manual method and 0.82 +/- 0.18 for the semiautomated method. The semiautomated method was faster than the manual trace method by an average of 4.6 minutes per patient. CONCLUSION The semiautomated computer method of measuring tumor volume was faster than the manual trace method. Semiautomated computer approaches offer an alternative to manual tracing for measuring serial tumor volumes in patients with high-grade brain neoplasms.
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Day RS, Rasouli-Nia A, Meservy J, Lari SU, Dobler K, Tsunoda S, Miyakoshi J, Takebe H, Murray D. Decreased host-cell reactivation of UV-irradiated adenovirus in human colon tumor cell lines that have normal post-UV survival. Photochem Photobiol 1999; 70:217-27. [PMID: 10461460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
An ongoing study in our laboratories is to examine the relationship of DNA repair defects to human cancer. Our underlying hypothesis has been that human tumors may arise that lack interesting DNA repair pathways if these pathways are important in preventing cancer. In this study, we found that the UV-irradiated adenoviruses showed hypersensitivity when assayed on monolayers of certain human colon tumor cell lines, including three that are reported to have defects in long patch DNA mismatch repair genes and one with no reported defect in mismatch repair. The survival curves showed two components. The first sensitive component was characteristic of 77-95% of the infections depending upon the cell line and the experiment and had an average slope indicating 4.8-fold hypersensitivity to UV. The average of the second-component slopes indicated that the remainder of the infections was accompanied by near-normal repair. Although the value of the first component indicated that the colon tumor lines supported the growth of UV-damaged adenoviruses poorly, the cell lines themselves showed the same post-UV colony-forming ability as did normal human fibroblasts, and their ability to support the growth of N-methyl-N'-nitro-N-nitrosoguanidine-damaged adenoviruses was normal, i.e. it parallelled their ability to repair O6-methylguanine in vitro. We previously observed two-component survival curves when assaying UV-irradiated adenovirus on monolayers of all of seven strains of fibroblasts from Cockayne's syndrome patients. By contrast, single-component curves have been obtained using 21 strains of normal human fibroblasts and seven other tumor lines. We interpret the two-component survival curves in terms of the defective transcription-coupled repair of UV-induced DNA damage that is characteristic both of Cockayne's and certain colon tumor cell lines. In addition, four mismatch repair-deficient colon tumor lines were resistant to killing by elevated levels of dG.
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Godbout R, Bisgrove DA, Shkolny D, Day RS. Correlation of B-FABP and GFAP expression in malignant glioma. Oncogene 1998; 16:1955-62. [PMID: 9591779 DOI: 10.1038/sj.onc.1201740] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The murine brain fatty acid binding protein (B-FABP) is encoded by a developmentally regulated gene that is expressed in radial glial cells and immature astrocytes. We have cloned the human B-FABP gene and have mapped it to chromosome 6q22-23. We show that B-FABP mRNA is expressed in human malignant glioma tumor biopsies and in a subset of malignant glioma cell lines, as well as in human fetal retina and brain. Malignant glioma tumors are characterized by cytoplasmic bundles of glial fibrillary acidic protein (GFAP), a protein normally expressed in mature astrocytes. Establishment of malignant glioma cell lines often results in loss of GFAP. The subset of malignant glioma cell lines that express GFAP mRNA also express B-FABP mRNA. Co-localization experiments in cell lines indicate that the same cells produce both GFAP and B-FABP. We suggest that some malignant gliomas may be derived from astrocytic precursor cells which can express proteins that are normally produced at different developmental stages in the astrocytic differentiation pathway.
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Ramakrishnan S, Hmelo CE, Day RS, Shirey WE, Huang Q. The integration of a novice user interface into a professional modeling tool. Proc AMIA Symp 1998:678-82. [PMID: 9929305 PMCID: PMC2232361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
This paper describes a software tool, the Oncology Thinking Cap (OncoTCAP) and reports on our efforts to develop a novice user interface to simplify the task of describing biological models of cancer and its treatment. Oncology Thinking Cap includes a modeling tool for making relationships explicit and provide dynamic feedback about the interaction between cancer cell kinetics, treatments, and patient outcomes. OncoTCAP supports student learning by making normally invisible processes visible and providing a representational tool that can be used to conduct thought experiments. We also describe our novice interface and report the results of initial usability testing.
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Getzenberg RH, Light BW, Lapco PE, Konety BR, Nangia AK, Acierno JS, Dhir R, Shurin Z, Day RS, Trump DL, Johnson CS. Vitamin D inhibition of prostate adenocarcinoma growth and metastasis in the Dunning rat prostate model system. Urology 1997; 50:999-1006. [PMID: 9426741 DOI: 10.1016/s0090-4295(97)00408-1] [Citation(s) in RCA: 173] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Risk factors for prostate cancer (PCa)-related mortality include old age, black race, and residence in northern latitudes. The objectives of this study are to examine the in vitro and in vivo effects of 1,25-dihydroxycholecalciferol (1,25-D3) and less-hypercalcemic analogues on the Dunning rat prostate adenocarcinoma model. METHODS To evaluate the effect of 1,25-D3 on PCa in vitro, we used the highly metastatic Mat-lylu (MLL) and moderately metastatic R3327-AT-2 (AT-2) Dunning prostate cell lines, and examined effects on growth, clonogenicity, differentiation, and cell cycle. In vivo analysis included examination of the effects of these compounds on tumor growth and metastasis. RESULTS Using both the 3-day MTT and 7-day clonogenic assay, 1,25-D3 demonstrated a growth inhibitory effect with a concentration for 50% inhibition (IC50) of approximately 20 microM for both MLL and AT-2. Cell cycle analysis of treated MLL cells (10 microM 1,25-D3 for 48 hours) had 25% more cells in the G0/G1 phase than did control cells. To examine the in vivo effect of 1,25-D3 and the less hypercalcemic vitamin D analogue, Ro25-6760 (or 6760), on MLL PCa growth and metastasis, tumors (5 x 10(5) cells) were implanted subcutaneously into the flank of Copenhagen rats on the same day that treatment was initiated with 1,25-D3 (1 microgram) or 6760 (1 or 5 micrograms); rats received treatment three times a week. After 3 weeks, 1,25-D3 and 6760 (5 micrograms dosing) resulted in an inhibition of tumor volume and a reduction in the number and size of lung metastases. CONCLUSIONS These preclinical studies demonstrate the profound in vitro, or in vivo, or both antiproliferative and differentiating effects of 1,25-D3 and 6760 on PCa and suggest that these drugs may have potential beneficial effects in the treatment of advanced PCa.
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Wang J, Hu L, Allalunis-Turner MJ, Day RS, Deen DF. Radiation-induced damage in two human glioma cell lines as measured by the nucleoid assay. Anticancer Res 1997; 17:4615-8. [PMID: 9494578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We measured radiation-induced damage and repair in MO59J and MO59K human glioma cell lines using the nucleoid halo assay. Although these two cell lines have different radiosensitivities when assayed for colony forming efficiency, our results indicated that there was no significant difference between the two in terms of the unwinding and rewinding of DNA supercoils, radiation-induced changes in nucleoid halo size or the kinetics of nucleoid halo lysis. The only differences noted were in the kinetics of recovery of radiation-induced changes in nucleoid halo size, with the more sensitive cell line (MO59J) showing a slightly faster recovery than the more resistant cell line (MO59K). However, this difference was not statistically different. Our data indicate that the different cellular radiosensitivities of MO59J and MO59K cells are probably not due to any differences in their supercoiled DNA structure as measured by the nucleoid halo assay.
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Allalunis-Turner J, Barron GM, Day RS. Intact G2-phase checkpoint in cells of a human cell line lacking DNA-dependent protein kinase activity. Radiat Res 1997; 147:284-7. [PMID: 9052673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cells respond to radiation-induced DNA damage in a cell cycle phase-specific manner as shown by (1) variation in radiosensitivity across the cell cycle and (2) checkpoints in G1 and G2 phase at which arrest of progression of cells through the phases of the cell cycle occurs. We studied these processes in cells of human glioma cell lines which lack (M059J(PK-)) or express (M059K(PK+)) DNA-dependent protein kinase (DNA-PK) activity. Cell populations enriched with cells of a specific cell cycle phase were y-irradiated and analyzed for cell survival. Although both cell lines were relatively sensitive in G1 phase and resistant in S phase, the differential sensitivity was greater in M059J(PK-) cells. In the studies on checkpoints, unsynchronized cells were irradiated and examined for evidence of cell cycle arrest. Neither cell line showed a postirradiation G1-phase arrest, presumably because of mutant p53 status. For M059J(PK-) cells, all doses tested (2.5-10 Gy) resulted in a significant increase in the proportion of G2/M-phase cells; however, for M059K(PK+) cells, a significant increase in G2/M phase was observed only after 10 Gy. These results suggest that the ability to activate the G2-phase checkpoint remains intact in cells which lack DNA-PK activity.
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Miyakoshi J, Kitagawa K, Yamagishi N, Ohtsu S, Day RS, Takebe H. Increased radiosensitivity of p16 gene-deleted human glioma cells after transfection with wild-type p16 gene. Jpn J Cancer Res 1997; 88:34-8. [PMID: 9045893 PMCID: PMC5921252 DOI: 10.1111/j.1349-7006.1997.tb00298.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The A1235 and T98 cell lines derived from human gliomas have homozygous deletions in their p16 genes and are radiosensitive and radioresistant, respectively, with respect to other established glioma cell lines. These differences in radiosensitivity may be due to variations to some extent among cell lines, rather than genetically defined resistance or sensitivity. We examined the effect on radiation sensitivity of introducing a wild-type p16 gene into both p16-deficient glioma cell lines. The plasmid pOPMTS containing human wild-type p16 cDNA and a neomycin resistance gene, or the control plasmid pOPRSV1, were transfected into these cells. Clones from both cell lines, which expressed wild-type p16 mRNA constitutively after transfection with pOPMTS, were more radiosensitive than the parental cells and clones obtained after transfection with the negative control plasmid.
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Hoover DR, Peng Y, Saah AJ, Detels RR, Day RS, Phair JP. Using multiple decrement models to estimate risk and morbidity from specific AIDS illnesses. Multicenter AIDS Cohort Study (MACS). Stat Med 1996; 15:2307-21; discussion 2337-40. [PMID: 8931203 DOI: 10.1002/(sici)1097-0258(19961115)15:21<2307::aid-sim450>3.0.co;2-i] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A simple non-parametric approach is developed to simultaneously estimate net incidence and morbidity time from specific AIDS illnesses in populations at high risk for death from these illnesses and other causes. The disease-death process has four-stages that can be recast as two sandwiching three-state multiple decrement processes. Non-parametric estimation of net incidence and morbidity time with error bounds are achieved from these sandwiching models through modification of methods from Aalen and Greenwood, and bootstrapping. An application to immunosuppressed HIV-1 infected homosexual men reveals that cytomegalovirus disease, Kaposi's sarcoma and Pneumocystis pneumonia are likely to occur and cause significant morbidity time.
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Gallinari P, Xu YZ, Goodman MF, Bloom LB, Jiricny J, Day RS. Base analog and neighboring base effects on substrate specificity of recombinant human G:T mismatch-specific thymine DNA-glycosylase. Biochemistry 1996; 35:12926-32. [PMID: 8841138 DOI: 10.1021/bi961022u] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We studied the substrate specificity of the human G:T mismatch-specific thymine glycosylase that initiates the repair of G:T and G:U base mismatches to G:C base pairs. Such mismatches arise when 5-methylcytosine or cytosine deaminate spontaneously (and hydrolytically) in DNA. Substrates were 45-bp DNA heteroduplexes that bore single G:T, m6G:T, 2,6-diaminopurine:T, 2-amino-6-(methylamino)-purine:T, 2-aminopurine:T, and G:m4T mispairs. The bases 5' to the poorly matched G were altered in selected G:T substrates to yield mispairs in four different contexts, ApG, CpG, GpG, and TpG. The recombinant thymine glycosylase was incubated with the 45-bp DNA substrates, each labeled at the 5'-terminus of the strand containing the mismatched T. The DNAs were then treated with 0.1 N NaOH to catalyze phosphodiester bond breakage at the newly-generated AP sites, and the products were analyzed on DNA sequencing gels. As indicated by the amounts of the 20-nt incision product, the removal of the thymine base by the enzyme increased linearly between 0 and 40 min at which time the generation of product from all substrates ceased, probably because of enzyme inactivation. The rate of incision was greatest (0.7 fmol/min) with DNA containing the G:T mispair followed by the DNA containing the m6G:T mispair (0.38 fmol/min) and the DNA with the 2-amino-6-(methylamino)purine:T mispair (0.15 fmol/ min); the extent of reaction was 90%, 40%, and 20% respectively. By contrast to previous findings with cell-free extracts, DNA substrates containing 2,6-diaminopurine:T, 2-aminopurine:T, and G:m4T mispairs were not incised (< 2%). The amount of incision of the 45-bp DNA substrates containing G:T mispairs in the CpG context was 3-12-fold greater than in the TpG, GpG, and ApG contexts.
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Reha-Krantz LJ, Nonay RL, Day RS, Wilson SH. Replication of O6-methylguanine-containing DNA by repair and replicative DNA polymerases. J Biol Chem 1996; 271:20088-95. [PMID: 8702729 DOI: 10.1074/jbc.271.33.20088] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The biological consequences of O6-methylguanine (m6G) in DNA are well recognized. When template m6G is encountered by DNA polymerases, replication is hindered and trans-lesion replication results in the preferential incorporation of dTMP opposite template m6G. Thus, unrepaired m6G in DNA is both cytotoxic and mutagenic. Yet, cell lines tolerant to m6G in DNA have been isolated, which indicates that some cellular DNA polymerases may replicate m6G-containing DNA with reasonable efficiency. Previous reports suggested that mammalian pol beta could not replicate m6G-containing DNA, but we find that pol beta can catalyze trans-lesion replication; however, the lesion must reside in the optimal context for pol beta activity, single- or short nucleotide gapped substrates. Primed single-stranded DNA templates, with or without template m6G, were poor substrates for pol beta as reported in earlier studies. In contrast, trans-lesion replication by bacteriophage T4 DNA polymerase was observed for primed single-stranded DNA templates. Replication of m6G-containing DNA by T4 DNA polymerase required the gp45 accessory protein that clamps the polymerase to the DNA template. The rate-limiting step in replicating m6G-containing DNAs by both DNA polymerases tested was incorporation of dTMP across from the lesion.
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Allalunis-Turner MJ, Zia PK, Barron GM, Mirzayans R, Day RS. Radiation-induced DNA damage and repair in cells of a radiosensitive human malignant glioma cell line. Radiat Res 1995; 144:288-93. [PMID: 7494872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The induction and repair of DNA double-strand breaks were studied in cells of two isogenic human malignant glioma cell lines which vary in their SF2 values by a factor of approximately 30. M059J cells are radiosensitive (SF2 = 0.02) and lack the p350 component of DNA-dependent protein kinase (DNA-PK); M059K cells are radioresistant (SF2 = 0.64) and express normal levels of DNA-PK. Zero integrated field gel electrophoresis and alkaline sucrose gradient experiments indicated that equivalent numbers of DNA lesions were produced by ionizing radiation in M059J and M059K cells. To compare the capacity of both lines to repair sublethal damage, the split-dose recovery experiment after exposure to equitoxic doses of radiation was carried out. Significant sublethal damage repair was shown for M059K cells, with a 5.8-fold increase in relative survival peaking at 4 h, whereas M059J cells showed little repair activity. Electrophoresis studies indicated that more double-strand breaks were repaired by 30 min in M059K cells than in M059J cells. These results suggest that deficient DNA repair processes may be a major determinant of radiosensitivity in M059J cells.
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Yamagishi N, Miyakoshi J, Ohtsu S, Day RS, Takebe H. Modification of the radiosensitivity of human cells to which simian virus 40 T-antigen was transfected. JOURNAL OF RADIATION RESEARCH 1995; 36:239-247. [PMID: 8913374 DOI: 10.1269/jrr.36.239] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Effects of the introduction of the Simian virus 40 T-antigen (SV40 T-Ag) gene to cultured human cells were examined in relation to radiosensitivity. Two relatively radioresistant tumor cell lines (T98 and G361) became significantly radiosensitive after the introduction of SV40 T-Ag, whereas radiosensitive tumor cell lines did not show a change in radiosensitivity. In contrast, a human fibroblast cell line became radioresistant after SV40 T-Ag introduction. T98 cells which have a mutation at codon 237 in the p53 gene were unable to form a complex between p53 protein and SV40 T-Ag, whereas G361, which became radiosensitive by a SV40 T-Ag introduction, formed the complex. This indicates that the status of p53 is independent of the change in radiosensitivity in the cell lines studied.
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Allalunis-Turner MJ, Lintott LG, Barron GM, Day RS, Lees-Miller SP. Lack of correlation between DNA-dependent protein kinase activity and tumor cell radiosensitivity. Cancer Res 1995; 55:5200-2. [PMID: 7585574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Lack of DNA-dependent protein kinase (DNA-PK) activity confers radiosensitivity and defective DNA double-strand break repair. Nine human malignant glioma cell lines were studied to determine whether differences in DNA-PK activity reflect differences in inherent radiosensitivity or are predictive of tumor treatment response. DNA-PK activity was present in all cell extracts, as were the DNA-PK proteins, DNA-PK catalytic subunit, Ku p70, and Ku p80. No correlation was found between the levels of DNA-PK activity and inherent radiosensitivity or in the tumor treatment response. These preliminary results suggest that variation in DNA-PK activity may not be a determinant of clinical response in malignant glioma.
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Xu YZ, Day RS. Incision at diaminopurine: thymine base pairs but not at guanine:O4-methylthymine base pairs in DNA by extracts of human cells. Biochemistry 1995; 34:7438-42. [PMID: 7779786 DOI: 10.1021/bi00022a017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cell-free extract from the A1235 human malignant glioma cell line was employed to study the possibility of incision at 2,6-diaminopurine:T (DiAP:T), 2-amino-6-methylaminopurine:T (AMAP:T), and G:O4-methylthymine (G:m4T) mismatches, each placed in a 45 bp DNA at a defined site. The incision of a 45 bp DNA containing a G:T mispair at the same site was followed to determine the relationship between base pair structure and repair activity (ies) in the extract. The cell-free extract incised DNAs containing DiAP:T, AMAP:T, and G:T pairs similarly. Reminiscent of the known pattern of incision at G:T mismatches, products from each substrate were consistent with two incisions, one immediately 5' and one immediately 3' to the mismatched T, and only in the strand containing the mismatched T. While DNA with an O6-methylguanine:T (m6G:T) pair was also incised, DNA containing the G:m4T pair was not, but was rendered inciseable by pretreatment with O6-methylguanine-DNA methyltransferase. Incision of DiAP:T-containing DNA by the extract was less in the presence of unlabeled DNA containing G:T mispairs than in the presence of A:T- or G:A-containing DNA or in the absence of competing DNA. We suggest that the mechanism operating on DiAP:T and/or AMAP:T pairs may be the same as the human G:T repair pathway, possibly initiated by the action of a glycosylase as described by Wiebauer and Jiricny [Wiebauer, K., & Jiricny, J. (1989) Nature 339, 234-236; Wiebauer, K., & Jiricny, J. (1990) Proc. Natl. Acad. Sci, U.S.A. 87, 5842-5845].(ABSTRACT TRUNCATED AT 250 WORDS)
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Day RS. Site specificity of incisions at G:T and O6-methylguanine:T base mismatches in DNA by human cell-free extracts. Biochemistry 1995; 34:6869-75. [PMID: 7756318 DOI: 10.1021/bi00020a034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cell-free extract from human tumor cell line A1235 (lacking O6-methylguanine-DNA methyltransferase) was employed to compare incision at G:T base mispairs with that at O6-methylguanine (m6G):T pairs at two different sites (sites 20 and 25) in 45-bp heteroduplexes. To study the effect of neighboring bases on the activity(ies), the base pair immediately 5' to the mismatched G at each site was varied to provide four contexts: CpG:T, TpG:T, ApG:T, and GpG:T (and two analogous series for m6G:T pairs). At site 20, cell-free extract produced observable incision only in the 45-bp DNA with the G:T mispair in the CpG:T context, giving a product with incisions immediately 5' and 3' to the mismatched T. We observed incision of neither the strand containing the mismatched G nor the DNAs with the site 20 ApG:T, GpG:T, and TpG:T mismatches. By contrast, at site 25, incision specificity was different. All four G:T mismatched DNAs were incised, and the ApG:T-25, GpG:T-25, and TpG:T-25 DNAs were incised 1-3 bonds 3' to the mismatched T, while similar in other respects to the CpG:T-25 DNA, which showed a pattern like the CpG:T-20 DNA. CpG:T-20 specific incision activity in the extract was strongly inhibited by both CpG:T (sites 20 and 25) DNAs, but at least 10-fold more poorly by DNAs with Apg:T-25 and GpG:T-25 pairs.(ABSTRACT TRUNCATED AT 250 WORDS)
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Lees-Miller SP, Godbout R, Chan DW, Weinfeld M, Day RS, Barron GM, Allalunis-Turner J. Absence of p350 subunit of DNA-activated protein kinase from a radiosensitive human cell line. Science 1995; 267:1183-5. [PMID: 7855602 DOI: 10.1126/science.7855602] [Citation(s) in RCA: 426] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The radiosensitive rodent mutant cell line xrs-5 is defective in DNA double-strand break repair and lacks the Ku component of the DNA-activated protein kinase, DNA-PK. Here radiosensitive human cell lines were analyzed for DNA-PK activity and for the presence of related proteins. The radiosensitive human malignant glioma M059J cell line was found to be defective in DNA double-strand break repair, but fails to express the p350 subunit of DNA-PK. These results suggest that DNA-PK kinase activity is involved in DNA double-strand break repair.
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