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91.
Characterization of ataxia telangiectasia fibroblasts with extended life-span through telomerase expression 总被引:8,自引:0,他引:8
Wood LD Halvorsen TL Dhar S Baur JA Pandita RK Wright WE Hande MP Calaf G Hei TK Levine F Shay JW Wang JJ Pandita TK 《Oncogene》2001,20(3):278-288
Ataxia-telangiectasia (A-T) is an autosomal recessive disease characterized by progressive cerebellar degeneration, immunodeficiencies, genomic instability and gonadal atrophy. A-T patients are hypersensitive to ionizing radiation and have an elevated cancer risk. Cells derived from A-T patients require higher levels of serum factors, exhibit cytoskeletal defects and undergo premature senescence in culture. We show here that expression of the catalytic subunit of telomerase (hTERT) in primary A-T patient fibroblasts can rescue the premature senescence phenotype. Ectopic expression of hTERT does not rescue the radiosensitivity or the telomere fusions in A-T fibroblasts. The hTERT+AT cells also retain the characteristic defects in cell-cycle checkpoints, and show increased chromosome damage before and after ionizing radiation. Although A-T patients have an increased susceptibility to cancer, the expression of hTERT in A-T fibroblasts does not stimulate malignant transformation. These immortalized A-T cells provide a more stable cell system to investigate the molecular mechanisms underlying the cellular phenotypes of Ataxia-telangiectasia. 相似文献
92.
93.
Hjarnaa PJ Jonsson E Latini S Dhar S Larsson R Bramm E Skov T Binderup L 《Cancer research》1999,59(22):5751-5757
A new class of recently discovered antineoplastic agents, the pyridyl cyanoguanidines, exert a potent antitumor activity in rodents after oral administration. Optimization in vitro and in vivo has resulted in the selection of the lead candidate CHS 828 (N-(6-chlorophenoxyhexyl)-N'cyano-N"-4-pyridylguanidine). CHS 828 was found to exert potent cytotoxic effects in human breast and lung cancer cell lines, with lesser effects on normal fibroblasts and endothelial cells. In a study using a panel of cell lines with different resistance patterns, the effects of CHS 828 showed a low correlation with the activity patterns of known anticancer agents, and no sensitivity to known mechanisms of multidrug resistance was observed. In nude mice bearing human tumor xenografts, CHS 828, at doses from 20 to 50 mg/kg/day p.o., inhibited the growth of MCF-7 breast cancer tumors and caused regression of NYH small cell lung cancer tumors. Oral administration of CHS 828 once weekly improved efficacy without increasing toxicity. CHS 828 was found to compare favorably with established chemotherapeutic agents such as cyclophosphamide, etoposide, methotrexate, and paclitaxel. In mice with NYH tumors, long-term survival (>6 months) was observed after treatment with CHS 828 was stopped. In conclusion, CHS 828 is an effective new antitumor agent, with a potentially new mechanism of action. CHS 828 is presently being tested in Phase I clinical trials in collaboration with the European Organization for Research and Treatment of Cancer. 相似文献
94.
Expression and subcellular localization of cyclin D1 protein in epithelial ovarian tumour cells 总被引:1,自引:0,他引:1
Dhar KK Branigan K Parkes J Howells RE Hand P Musgrove C Strange RC Fryer AA Redman CW Hoban PR 《British journal of cancer》1999,81(7):1174-1181
The expression of cyclin D1 protein in tumour sections from 81 patients with epithelial ovarian cancer was analysed using immunohistochemistry. The tumours that overexpressed cyclin D1 in more than 10% of neoplastic cells were considered positive. Thus overexpression of cyclin D1 was observed in 72/81 (89%) of the cases examined. Protein was detected in both the nucleus and the cytoplasm in 24/81 (30%) and localized exclusively in the cytoplasm in 48/81 (59%) of the tumours. Cyclin D1 was overexpressed in both borderline and invasive tumours. There was no association between protein overexpression and tumour stage and differentiation. Furthermore, no correlation between cyclin D1 expression and clinical outcome was observed. However, in tumours overexpressing cyclin D1 (n = 72), the proportion displaying exclusively cytoplasmic localization of protein was higher in those with serous compared with non-serous histology (P = 0.004, odds ratio 4.8, 95% confidence interval 1.4-19.1). Western analysis using a monoclonal antibody to cyclin D1 identified a 36 kDa protein in homogenates from seven tumours displaying cytoplasmic only and one tumour demonstrating both nuclear and cytoplasmic immunostaining. Using restriction fragment length polymorphism polymerase chain reaction and PCR-multiplex analysis, amplification of the cyclin D1 gene (CCND1 was detected in 1/29 of the tumours demonstrating overexpression of cyclin D1 protein. We conclude that deregulation of CCND1 expression leading to both cytoplasmic and nuclear protein localization is a frequent event in ovarian cancer and occurs mainly in the absence of gene amplification. 相似文献
95.
96.
Ilufredo Y. Tantoy Bruce A. Cooper Anand Dhruva Janine Cataldo Steven M. Paul Yvette P. Conley Marilyn Hammer Fay Wright Laura B. Dunn Jon D. Levine Christine Miaskowski 《Journal of pain and symptom management》2018,55(3):808-834
Context
Studies on multiple dimensions of the symptom experience of patients with gastrointestinal cancers are extremely limited.Objective
Purpose was to evaluate for changes over time in the occurrence, severity, and distress of seven common symptoms in these patients.Methods
Patients completed Memorial Symptom Assessment Scale, six times over two cycles of chemotherapy (CTX). Changes over time in occurrence, severity, and distress of pain, lack of energy, nausea, feeling drowsy, difficulty sleeping, and change in the way food tastes were evaluated using multilevel regression analyses. In the conditional models, effects of treatment group (i.e., with or without targeted therapy), age, number of metastatic sites, time from cancer diagnosis, number of prior cancer treatments, cancer diagnosis, and CTX regimen on enrollment levels, as well as the trajectories of symptom occurrence, severity, and distress were evaluated.Results
Although the occurrence rates for pain, lack of energy, feeling drowsy, difficulty sleeping, and change in the way food tastes declined over the two cycles of CTX, nausea and numbness/tingling in hands/feet had more complex patterns of occurrence. Severity and distress ratings for the seven symptoms varied across the two cycles of CTX.Conclusions
Demographic and clinical characteristics associated with differences in enrollment levels as well as changes over time in occurrence, severity, and distress of these seven common symptoms were highly variable. These findings can be used to identify patients who are at higher risk for more severe and distressing symptoms during CTX and to enable the initiation of preemptive symptom management interventions. 相似文献97.
98.
P Reed D Bhatnagar H Dhar P H Winocour 《Clinica chimica acta; international journal of clinical chemistry》1986,161(2):191-199
A precise and easy method for measuring glycated serum albumin using affinity chromatography and immunoturbidimetry on a centrifugal analyser, ensuring complete recovery of serum albumin is described. 相似文献
99.
OBJECTIVE: Inability to understand speech in noise has been cited repeatedly as the principal complaint of hearing aid users. While data exist documenting the benefit provided by hearing aids with directional microphones when listening to speech in noise, little work has been done to develop a standard clinical protocol for fitting these hearing aids. Our goal was to evaluate a clinical measure of the acoustic directivity of a directional hearing aid, including its association with a test of speech perception in noise. DESIGN: The performance of two commercially available directional behind-the-ear (BTE) hearing aids was evaluated using the Hearing in Noise Test (HINT) and the Real Ear Aided Response (REAR) on 24 adult participants with symmetric, mild to moderately severe, sensorineural hearing loss. The HINT was conducted with the speech signal presented from 0 degrees and the noise from 180 degrees and either 135 degrees or 225 degrees, depending on the ear tested. REAR was measured at the above three angles using swept pure tones, and these measures were used to compute in situ directivity for each subject and hearing aid. CONCLUSIONS: Directional benefit for the HINT was greatest when noise was presented from the azimuth of the published polar diagram null of a given hearing aid in its directional mode (180 or 135/225 degrees). The only significant correlation between HINT and REAR results, however, was found when the noise source was at 180 degrees. These results confirm the validity of using real ear measures as a way to assess directionality in situ, but also indicate the complexity of predicting perceptual benefit from them. These data suggest that factors beyond acoustic directionality may contribute to improvement in speech perception in noise when such improvements are found. 相似文献
100.
Graphene supports in vitro proliferation and osteogenic differentiation of goat adult mesenchymal stem cells: potential for bone tissue engineering 下载免费PDF全文
Hoda Elkhenany Lisa Amelse Andersen Lafont Shawn Bourdo Marc Caldwell Nancy Neilsen Enkeleda Dervishi Oshin Derek Alexandru S. Biris David Anderson Madhu Dhar 《Journal of applied toxicology : JAT》2015,35(4):367-374
Current treatments for bone loss injuries involve autologous and allogenic bone grafts, metal alloys and ceramics. Although these therapies have proved useful, they suffer from inherent challenges, and hence, an adequate bone replacement therapy has not yet been found. We hypothesize that graphene may be a useful nanoscaffold for mesenchymal stem cells and will promote proliferation and differentiation into bone progenitor cells. In this study, we evaluate graphene, a biocompatible inert nanomaterial, for its effect on in vitro growth and differentiation of goat adult mesenchymal stem cells. Cell proliferation and differentiation are compared between polystyrene‐coated tissue culture plates and graphene‐coated plates. Graphitic materials are cytocompatible and support cell adhesion and proliferation. Importantly, cells seeded on to oxidized graphene films undergo osteogenic differentiation in fetal bovine serum‐containing medium without the addition of any glucocorticoid or specific growth factors. These findings support graphene's potential to act as an osteoinducer and a vehicle to deliver mesenchymal stem cells, and suggest that the combination of graphene and goat mesenchymal stem cells provides a promising construct for bone tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献