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Léonard F, Stewart DA. Properties of short channel ballistic carbon nanotube transistors with ohmic contacts. NANOTECHNOLOGY 2006; 17:4699-4705. [PMID: 21727600 DOI: 10.1088/0957-4484/17/18/029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present self-consistent, non-equilibrium Green's function calculations of the characteristics of short channel carbon nanotube transistors, focusing on the regime of ballistic transport with ohmic contacts. We first establish that the band line-up at the contacts is renormalized by charge transfer, leading to Schottky contacts for small diameter nanotubes and ohmic contacts for large diameter nanotubes, in agreement with recent experiments. For short channel ohmic contact devices, source-drain tunnelling and drain-induced barrier lowering significantly impact the current-voltage characteristics. Furthermore, the ON state conductance shows a temperature dependence, even in the absence of phonon scattering or Schottky barriers. This last result also agrees with recently reported experimental measurements.
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Parkins MD, Bahlis N, Brown C, Savoie L, Chaudhry A, Russell JA, Stewart DA. Overnight storage of autologous stem cell apheresis products before cryopreservation does not adversely impact early or long-term engraftment following transplantation. Bone Marrow Transplant 2006; 38:609-14. [PMID: 16980991 DOI: 10.1038/sj.bmt.1705501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To reduce costs and avoid inconvenient overtime work, our institution changed policy in September 2000 so that autologous stem cell apheresis products were stored overnight before cryopreservation rather than immediately processed. This retrospective review was conducted to evaluate the possible impact of this policy change on hematopoietic engraftment following autologous stem cell transplantation (ASCT). In total, 229 consecutive lymphoma patients who underwent a single, unpurged ASCT in Calgary between January 1995 and November 2003 were evaluated. Of these patients, 131 patients' autografts underwent immediate processing and cryopreservation before September 2000, and 98 patients' autografts underwent next-day cryopreservation after overnight storage following this date. Results of univariate and multivariate analyses demonstrated no adverse effect of overnight storage before cryopreservation on the number of days to initial engraftment of platelets or neutrophils, on the proportion of patients with low blood counts 6 months post-ASCT, or on lymphoma relapse rates or overall survival post-ASCT. These data suggest that overnight storage of the autograft before cryopreservation does not adversely affect graft viability or influence long-term disease status, and support the continued use of overnight storage of stem cells before cryopreservation as a convenient, cost reduction measure.
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Shoaib T, Stewart DA, Mackie RM, Gray HW, Soutar DS. The unexpected sites of melanoma regional recurrences. J Plast Reconstr Aesthet Surg 2006; 59:955-60. [PMID: 16920588 DOI: 10.1016/j.bjps.2005.12.036] [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] [Received: 06/14/2005] [Revised: 11/02/2005] [Accepted: 12/09/2005] [Indexed: 11/18/2022]
Abstract
UNLABELLED Sentinel node biopsy is a means of identifying nodal involvement in melanoma and lymphoscintigraphy identifies unpredictable sites of melanoma sentinel nodes in up to 25% of cases. Whilst there is a dearth of recent publications in this area, it nevertheless remains an interesting observation that unpredictable sites of sentinel nodes are so common as to be accepted as normal. This study was performed to determine if this high rate of unpredictable lymphatic drainage was reflected in clinical practice, where therapeutic lymph node dissections were performed for pathologically confirmed regional disease. METHODS Patients undergoing regional lymph node dissections for histologically proven malignant melanoma were identified from a computer database. Patient details were analysed from case records. RESULTS Two hundred and forty-three case records were examined and 237 were suitable for analysis. The site of the primary was the head and neck in 50 (21%), trunk in 73 (31%), upper limb in 27 (11%) and lower limb in 87 (37%). In 15 cases (6%), the first site of regional disease was unpredictable. In these 15 cases, the site of the primary was the head and neck in two, trunk in 11, upper limb in one and lower limb in one. In 37 cases (16%), a subsequent site of nodal recurrence was unpredictable. Clinicians should be aware that patients with melanomas, particularly of the trunk, especially those in whom a therapeutic nodal dissection has been performed, may have nodal disease at unpredictable sites. However, unexpected sites of regional disease are not as common as sentinel node biopsy would suggest. Guidelines for lymph node examination in cutaneous melanoma are suggested based on these findings.
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Velev JP, Belashchenko KD, Stewart DA, van Schilfgaarde M, Jaswal SS, Tsymbal EY. Negative spin polarization and large tunneling magnetoresistance in epitaxial Co/SrTiO(3)/Co magnetic tunnel junctions. PHYSICAL REVIEW LETTERS 2005; 95:216601. [PMID: 16384165 DOI: 10.1103/physrevlett.95.216601] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Indexed: 05/05/2023]
Abstract
We perform an ab initio study of spin-polarized tunneling in epitaxial Co/SrTiO(3)/Co magnetic tunnel junctions with bcc Co(001) electrodes. We predict a large tunneling magnetoresistance in these junctions, originating from a mismatch in the majority- and minority-spin bands both in bulk bcc Co and at the Co/SrTiO(3)/Co interface. The intricate complex band structure of SrTiO(3) enables efficient tunneling of the minority d electrons which causes the spin polarization of the Co/SrTiO(3)/Co interface to be negative in agreement with experimental data. Our results indicate that epitaxial Co/SrTiO(3)/Co magnetic tunnel junctions with bcc Co(001) electrodes are a viable alternative for device applications.
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Stewart DA, Paterson AHG, Ruether JD, Russell J, Craighead P, Smylie M, Mackey J. High-dose mitoxantrone–vinblastine–cyclophosphamide and autologous stem cell transplantation for stage III breast cancer: final results of a prospective multicentre study. Ann Oncol 2005; 16:1463-8. [PMID: 15946980 DOI: 10.1093/annonc/mdi268] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Stage III breast cancer patients continue to suffer high relapse and death rates despite standard chemotherapy regimens. High-dose alkylator chemotherapy does not further improve outcome. This phase II study evaluated a novel high-dose chemotherapy regimen which combined active breast cancer agents with differing mechanisms of action. PATIENTS AND METHODS Eligibility included at least seven involved axillary nodes (AxLNs) for tumours <5 cm, at least four AxLNs for tumours >5 cm or locally advanced breast cancer (LABC). Patients received four cycles of fluorouracil-adriamycin-cyclophosphamide (FAC) followed by one cycle of mitoxantrone 63 mg/m(2)-vinblastine 12.5 mg/m(2)-cyclophosphamide 6 g/m(2) (MVC) with autologous blood stem cell transplantation (ASCT). RESULTS Between April 1995 and December 1998, 92 patients aged 21-65 years (median 45 years) were enrolled, of whom 25 were treated preoperatively for LABC and 67 were treated postoperatively. Although there was no early treatment-related mortality, one late death occurred from secondary acute myeloid leukaemia. The 7-year event-free and overall survival rates were 53% (95% confidence interval 42-64%) and 62% (95% CI 52-73%), respectively, with no significant difference between pre- and postoperative groups. CONCLUSION FAC followed by MVC-ASCT is feasible and reasonably well tolerated, but does not result in improved survival rates compared with other conventional or high-dose regimens for stage III breast cancer.
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Thirukkumaran CM, Luider JM, Stewart DA, Alain T, Russell JA, Auer IA, Forsyth P, Morris DG. Biological purging of breast cancer cell lines using a replication-competent oncolytic virus in human stem cell autografts. Bone Marrow Transplant 2005; 35:1055-64. [PMID: 15821774 DOI: 10.1038/sj.bmt.1704931] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autologous hematological stem cell transplantation (ASCT) is used for the treatment of many hematological and several solid cancers. ASCT, however, has proven disappointing as a therapeutic strategy for breast cancer. Our group and others have previously shown that breast cancer micrometastases found in patients' apheresis products (APs) predict shorter progression-free and overall survival. The implications of this finding are twofold: (i) contaminating tumor cells (CTCs) in AP reflect a higher systemic disease burden and/or (ii) reinfused CTCs contribute to relapse/progressive disease. To date, purging strategies have been disappointing. We have previously demonstrated the oncolytic properties of reovirus in in vitro, in vivo and ex vivo systems. In the present study, we tested the hypothesis that reovirus purges CTCs in a breast cancer cell line purging model. Reovirus-infected human breast cancer cell lines (HTB 133, HTB 132, SKBR3 and MCF7) exhibited cell death within days. Admixtures of AP with cells from breast tumor cell lines, which were then exposed to reovirus, showed complete purging of CTCs (assessed via flow cytometry/tumor cell outgrowth analysis) without deleterious effect on CD34+ cells. Our results provide preclinical support for the ex vivo use of reovirus as a purging modality for breast cancer during ASCT.
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Chow LQM, Bahlis N, Russell J, Chaudhry A, Morris D, Brown C, Stewart DA. Autologous transplantation for primary systemic AL amyloidosis is feasible outside a major amyloidosis referral centre: the Calgary BMT Program experience. Bone Marrow Transplant 2005; 36:591-6. [PMID: 16062177 DOI: 10.1038/sj.bmt.1705112] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent reports from large amyloidosis referral centers suggest that primary systemic AL amyloidosis patients treated with high-dose melphalan (HDM) and autologous stem cell transplantation (ASCT) survive longer than historical controls treated with less intensive chemotherapy, despite high transplant-related mortality (TRM) rates of >10%. A retrospective review was conducted to determine if the outcome of ASCT for AL amyloidosis at our institution was similar to that reported at major amyloidosis referral centers. Over a 7 year period, we treated a total of 15 AL amyloidosis patients with ASCT, including four with poor prognosis cardiac or multisystem involvement. No TRM was observed. Overall, 10 patients (67%) achieved a complete hematological response and four patients (27%) achieved a complete organ response. The 4-year event-free and overall survival rates were 60% (95% CI 32-89%) and 75% (95% CI 50-100%), respectively. One patient, who presented with cardiac failure and multiorgan involvement with colonic bleeding currently remains in complete remission 62 months post-ASCT. In conclusion, ASCT for primary AL amyloidosis can safely be performed at experienced transplant centers that are not associated with major amyloidosis referral centers, and is feasible for patients who have multisystem involvement, particularly for motivated patients with good performance status.
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Stewart DA, Léonard F. Energy conversion efficiency in nanotube optoelectronics. NANO LETTERS 2005; 5:219-222. [PMID: 15794599 DOI: 10.1021/nl048410z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present theoretical performance estimates for nanotube optoelectronic devices under bias. Current-voltage characteristics of illuminated nanotube p-n junctions are calculated using a self-consistent nonequilibrium Green's function approach. Energy conversion rates reaching tens of percent are predicted for incident photon energies near the band gap energy. In addition, the energy conversion rate increases as the diameter of the nanotube is reduced, even though the quantum efficiency shows little dependence on nanotube radius. These results indicate that the quantum efficiency is not a limiting factor for use of nanotubes in optoelectronics.
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Stewart DA, Léonard F. Photocurrents in nanotube junctions. PHYSICAL REVIEW LETTERS 2004; 93:107401. [PMID: 15447449 DOI: 10.1103/physrevlett.93.107401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2003] [Revised: 06/14/2004] [Indexed: 05/24/2023]
Abstract
Photocurrents in nanotube p-n junctions are calculated using a nonequilibrium Green function quantum transport formalism. The short-circuit photocurrent displays band-to-band transitions and photon-assisted tunneling, and has multiple sharp peaks in the infrared, visible, and ultraviolet. The operation of such devices in the nanoscale regime leads to unusual size effects, where the photocurrent scales linearly and oscillates with device length. The oscillations can be related to the density of states in the valence band, a factor that also determines the relative magnitude of the photoresponse for different bands.
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Cheng T, Forsyth P, Chaudhry A, Morris D, Glück S, Russell JA, Stewart DA. High-dose thiotepa, busulfan, cyclophosphamide and ASCT without whole-brain radiotherapy for poor prognosis primary CNS lymphoma. Bone Marrow Transplant 2003; 31:679-85. [PMID: 12692608 DOI: 10.1038/sj.bmt.1703917] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Treatment of primary central nervous system lymphoma (PCNSL) with combined high-dose methotrexate (HD-MTX)-based chemotherapy and whole-brain radiotherapy (WBRT) is associated with severe neurotoxicity, but high relapse rates are associated with the use of either modality alone. In an attempt to improve upon these dismal results, we treated seven PCNSL patients with HD-MTX-based induction therapy followed by thiotepa, busulfan, cyclophosphamide (TBC), and autologous stem cell transplant (ASCT), without WBRT. Six of these patients had at least one of the following poor prognostic features: Karnofsky performance status (KPS) <or=50%, age >60 years, or relapsed disease. All but one patient tolerated the treatment well and experienced improvements in neurological function and overall performance status post-transplant. No treatment-induced neurotoxicity (dementia, ataxia, and incontinence) was observed although the follow-up is short. One early treatment-related death occurred in a patient with multiple comorbid medical conditions. The other six patients achieved a complete response (CR) after TBC and ASCT. Five patients are currently alive and relapse-free at 5, 8, 24, 36, and 42 months from diagnosis. One additional patient relapsed and died 33 months after diagnosis. Two of the seven patients received TBC/ASCT as the only treatment after disease progression following their initial chemotherapy and both remain relapse-free at the time of this report, 22 and 31 months post-TBC/ASCT. In conclusion, prolonged CR can be attained after chemotherapy-only treatment of poor prognosis PCNSL. Furthermore, this small series suggests that high-dose chemotherapy for PCNSL should include drugs that penetrate the CNS such as busulfan and thiotepa rather than standard lymphoma regimens such as BEAM.
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Zia MI, Forsyth P, Chaudhry A, Russell J, Stewart DA. Possible benefits of high-dose chemotherapy and autologous stem cell transplantation for adults with recurrent medulloblastoma. Bone Marrow Transplant 2002; 30:565-9. [PMID: 12407430 DOI: 10.1038/sj.bmt.1703725] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2002] [Accepted: 05/21/2002] [Indexed: 11/09/2022]
Abstract
In an attempt to improve the dismal prognosis of adults with recurrent medulloblastoma, six patients were treated with aggressive salvage therapy including high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT). At relapse, all patients underwent surgical debulking followed by HDCT/ASCT and then radiotherapy when possible. The treatment plan included two cycles of HDCT/ASCT; first with cyclophosphamide, etoposide and carboplatin (CECb) and then 2 months later with cyclophosphamide and thiotepa (CT). Three of the six patients received the planned therapy. One patient experienced severe toxicity requiring life-sustaining therapy. This patient developed multi-organ dysfunction including multiple enhancing lesions in both cerebral hemispheres that slowly resolved over several months. Two other patients did not mobilize sufficient stem cells for two ASCT procedures. They received one ASCT conditioned with cyclophosphamide, thiotepa and carboplatin (CTCb). Three of six patients had a complete response (CR); the other three had a partial response (PR). Following the first ASCT, median duration of response was 13.5 months (range 9-29 months) and median survival was 21.5 months (range 12-42 months). There was no treatment-related mortality. We conclude that HDCT/ASCT with CECb-CT or CTCb is active against recurrent medulloblastoma in adults and may be associated with prolonged remissions. Multiple enhancing cerebral lesions on brain MRI early post-HDCT/ASCT may be a consequence of the treatment rather than metastatic disease.
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Jenkins D, DiFrancesco L, Chaudhry A, Morris D, Glück S, Jones A, Woodman R, Brown CB, Russell J, Stewart DA. Successful treatment of post-transplant lymphoproliferative disorder in autologous blood stem cell transplant recipients. Bone Marrow Transplant 2002; 30:321-6. [PMID: 12209355 DOI: 10.1038/sj.bmt.1703603] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2002] [Accepted: 03/22/2002] [Indexed: 11/09/2022]
Abstract
We report three cases of post-transplant lymphoproliferative disorder (PTLD) in the context of autologous stem cell transplantation (ASCT) for multiple myeloma (MM) and non-Hodgkin's lymphoma. The first two cases received ASCT for MM, one with a CD34-selected autograft and the other with an unmanipulated autograft. Both these cases of PTLD achieved a complete response following treatment with IVIG, gancyclovir, solumedrol and interferon (IFN). The third case received ASCT with an unmanipulated autograft for relapsed angioimmunoblastic lymphoma. He also achieved a complete response but only after rituximab was added to IVIG, gancyclovir, solumedrol and IFN. None of these patients experienced a relapse of their PTLD with follow-up ranging from 1.5 to 5 years. These cases highlight the importance of considering PTLD in the differential diagnosis of lymphadenopathy and fever post ASCT. They also demonstrate the possibility of durable complete remission of post-ASCT PTLD following antiviral and immune modulating therapy.
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Stewart DA, Thomas SD, Mayfield CA, Miller DM. Psoralen-modified clamp-forming antisense oligonucleotides reduce cellular c-Myc protein expression and B16-F0 proliferation. Nucleic Acids Res 2001; 29:4052-61. [PMID: 11574688 PMCID: PMC60243 DOI: 10.1093/nar/29.19.4052] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The c-myc protooncogene plays an important role in the abnormal growth pattern of melanoma cells. In an attempt to inhibit c-Myc expression and the growth of an established murine melanoma cell line, we targeted homopurine sequences within the mouse myc mRNA with modified antisense oligonucleotides (AS ODNs). Psoralen was conjugated to the 5'-end of these clamp-forming oligonucleotides (clamp ODNs). Gel mobility shift analysis demonstrated a sequence-specific interaction between the active clamp ODNs (Myc-E2C and Myc-E3C) and the 1.4 kb c-myc mRNA, but no interaction with the control clamp ODN (SCR**). This association was further confirmed by thermal denaturation studies. In vitro translation assays demonstrated that both Myc-E2C and Myc-E3C at 5 microM inhibited c-Myc expression >99% after UV activation at 366 nm. Immunostaining of B16-F0 cells with a c-Myc monoclonal antibody revealed a significant reduction in c-Myc after clamp ODN treatment compared with the untreated or SCR** control-treated cells. This result was corroborated by western blot analysis. Utilizing the MTT assay to determine the effects of ODN-mediated c-Myc reduction on B16-F0 growth, we observed 60 and 64% reductions in growth after treatment with 5 microM Myc-E3C and Myc-E2C, respectively. We attribute the enhanced effectiveness of the clamp ODNs to psoralen activation. Our preliminary data suggest that inhibiting c-Myc overexpression results in a significant reduction in abnormal proliferation of B16-F0 melanoma cells and that the increased efficiency of clamp ODNs may provide an important advantage for their use in antisense therapies.
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Forsyth PA, Stewart DA. Oligodendrogliomas: the Achilles' heel of malignant gliomas. Can J Neurol Sci 2001; 28:187-8. [PMID: 11513335 DOI: 10.1017/s0317167100001311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Stewart DA, Guo D, Luider J, Auer I, Klassen J, Morris D, Brown CB, Chaudhry A, Glück S, Russell JA. The CD3- 16+ 56+ NK cell count independently predicts autologous blood stem cell mobilization. Bone Marrow Transplant 2001; 27:1237-43. [PMID: 11548841 DOI: 10.1038/sj.bmt.1703070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Better predictive factors for autologous blood stem cell mobilization (BSCM) are needed. The purpose of this study was to determine if an independent association exists between lymphocyte or NK cell counts and BSCM. Data were analyzed on 141 consecutive patients aged 19-69 years (median 45) who received combined chemotherapy plus G-CSF for BSCM, and who had measurements of immune cells prior to BSCM. Of the 141 patients, 41% had breast cancer, 14% Hodgkin's disease, 34% non-Hodgkin's lymphoma, and 11% other diagnoses. BSCM involved dose-intensive cyclophosphamide, etoposide, cisplatin (DICEP) plus G-CSF 300 microg (<70 kg) or 480 microg (>70 kg) for 45% of patients, while the remaining 55% received other chemotherapy plus similar doses of G-CSF. Only a single apheresis was performed for 94% of patients. The following factors were analyzed for predictors of BSCM: age, gender, prior chemotherapy, prior radiotherapy, diagnosis, disease status, marrow involvement, mobilization regimen, Hb, WBC, platelet count, B cell, T cell, and NK cell counts. The peripheral blood CD34+ counts on the first day of apheresis (PBCD34) were 6-1783 x 10(6)/l (median 150). The PBCD34 count correlated strongly with the number of CD34+ cells collected/l blood apheresed and with the number of CD34+ cells collected/kg. By multivariate analysis using continuous variables, relapsed status (P = 0.0003), not using DICEP mobilization (P = 0.0001), female gender (P = 0.0057), low platelet count (P = 0.051), and low CD3- 16+ 56+ count (P = 0.0158) were associated with low PBCD34 counts. Using categorical variables, the only factors that independently predicted a PBCD34 count <150 x 10(6)/l were: >1 prior chemotherapy regimen (odds ratio = 5.12, P = 0.0003), not using DICEP mobilization (odds ratio = 4.94, P = 0.0001), and CD3- 16+ 56+ count <125 x 10(6)/l (odds ratio= 2.58, P = 0.0157). In conclusion, the CD3- 16+ 56+ count may be a useful additional predictor of BSCM and warrants further study.
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Carter JC, Stewart DA, Fairburn CG. Eating disorder examination questionnaire: norms for young adolescent girls. Behav Res Ther 2001; 39:625-32. [PMID: 11341255 DOI: 10.1016/s0005-7967(00)00033-4] [Citation(s) in RCA: 256] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This paper reports young adolescent female norms for the Eating Disorder Examination Questionnaire (EDE-Q). The standardization sample was comprised of 808 girls aged between 12 and 14 years from three single-sex schools (one private and two state schools). Means, standard deviations and percentile ranks for raw EDE-Q subscale scores are presented. Prevalence figures for key eating disorder behaviors over the previous two weeks were as follows: 4% self-induced vomiting; 1% laxative misuse; 0.4% diuretic misuse; and 8% regular binge eating.
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Stewart DA, Carter JC, Drinkwater J, Hainsworth J, Fairburn CG. Modification of eating attitudes and behavior in adolescent girls: A controlled study. Int J Eat Disord 2001; 29:107-18. [PMID: 11429973 DOI: 10.1002/1098-108x(200103)29:2<107::aid-eat1000>3.0.co;2-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the effectiveness of a school-based eating disorder prevention program designed to reduce dietary restraint and concern about shape and weight among adolescent girls. METHOD A total of 474 girls aged 13-14 years received the program as part of their normal school curriculum. An assessment-only control group included 386 pupils. Measures of eating disorder features, self-esteem, and knowledge were administered before and after the intervention and at 6-month follow-up. RESULTS Immediately following the intervention, there was a small reduction in dietary restraint and attitudes to shape and weight in the index group, whereas there was no change in the control group. This reduction was not maintained at 6-month follow-up although the dietary restraint scores of the index group remained lower than those of the control group. DISCUSSION This prevention program achieved change in eating attitudes and behavior, although the change was modest in size and not sustained. Focusing on a high-risk subgroup of dieters might be a more fruitful primary prevention strategy.
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Jakubczak JL, Rollence ML, Stewart DA, Jafari JD, Von Seggern DJ, Nemerow GR, Stevenson SC, Hallenbeck PL. Adenovirus type 5 viral particles pseudotyped with mutagenized fiber proteins show diminished infectivity of coxsackie B-adenovirus receptor-bearing cells. J Virol 2001; 75:2972-81. [PMID: 11222722 PMCID: PMC115923 DOI: 10.1128/jvi.75.6.2972-2981.2001] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2000] [Accepted: 11/20/2000] [Indexed: 11/20/2022] Open
Abstract
A major limitation of adenovirus type 5 (Ad5)-based gene therapy, the inability to target therapeutic genes to selected cell types, is attributable to the natural tropism of the virus for the widely expressed coxsackievirus-adenovirus receptor (CAR) protein. Modifications of the Ad5 fiber knob domain have been shown to alter the tropism of the virus. We have developed a novel system to rapidly evaluate the function of modified fiber proteins in their most relevant context, the adenoviral capsid. This transient transfection/infection system combines transfection of cells with plasmids that express high levels of the modified fiber protein and infection with Ad5.beta gal.Delta F, an E1-, E3-, and fiber-deleted adenoviral vector encoding beta-galactosidase. We have used this system to test the adenoviral transduction efficiency mediated by a panel of fiber protein mutants that were proposed to influence CAR interaction. A series of amino acid modifications were incorporated via mutagenesis into the fiber expression plasmid, and the resulting fiber proteins were subsequently incorporated onto adenoviral particles. Mutations located in the fiber knob AB and CD loops demonstrated the greatest reduction in fiber-mediated gene transfer in HeLa cells. We also observed effects on transduction efficiency with mutations in the FG loop, indicating that the binding site may extend to the adjacent monomer in the fiber trimer and in the HI loop. These studies support the concept that modification of the fiber knob domain to diminish or ablate CAR interaction should result in a detargeted adenoviral vector that can be combined simultaneously with novel ligands for the development of a systemically administered, targeted adenoviral vector.
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Stewart DA, Law MC, Rosenbaum P, Willms DG. A qualitative study of the transition to adulthood for youth with physical disabilities. Phys Occup Ther Pediatr 2001; 21:3-21. [PMID: 12043171 DOI: 10.1300/j006v21n04_02] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of this qualitative study was to explore the experiences, perceptions, and needs of youth with physical disabilities in transition from adolescence to adulthood. Purposeful sampling strategies were used to select 34 study participants who lived in three regions of south-central Ontario, Canada. Data collection methods were individual and focus group interviews, and were guided by a set of open-ended questions. An editing style of analysis sorted the text into codes for description and interpretation. Themes emerged about context, the transition process, needs, and services. Participants identified a poor fit between young persons with disabilities and the adult world they were entering. They recommended that services be focused on environmental supports to enable them to "build their own bridges" to the adult world. Community-based transition services need to be planned in collaboration with youth with disabilities and their parents. Concepts of person-environment fit and health promotion can be incorporated into services to enable young persons with disabilities to experience a smooth transition from adolescence to adulthood.
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Duggan PR, Guo D, Luider J, Auer I, Klassen J, Chaudhry A, Morris D, Glück S, Brown CB, Russell JA, Stewart DA. Predictive factors for long-term engraftment of autologous blood stem cells. Bone Marrow Transplant 2000; 26:1299-304. [PMID: 11223969 DOI: 10.1038/sj.bmt.1702708] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Data from 170 consecutive patients aged 19-66 years (median age 46 years) who underwent unmanipulated autologous blood stem cell transplant (ASCT) were analyzed to determine if total CD34+ cells/kg infused, CD34+ subsets (CD34+41+, CD34+90+, CD34+33-, CD34+38-, CD34+38-DR-), peripheral blood CD34+ cell (PBCD34+) count on first apheresis day, or various clinical factors were associated with low blood counts 6 months post ASCT. Thirty-four patients were excluded from analysis either because of death (n = 17) or re-induction chemotherapy prior to 6 months post ASCT (n = 13), or because of lack of follow-up data (n = 4). Of the remaining 136 patients, 46% had low WBC ( < 4 x 10(9)/l), 41% low platelets (<150 x 10(9)/l), and 34% low hemoglobin ( < 120 g/l) at a median of 6 months following ASCT. By Spearman's rank correlation, both the total CD34+ cell dose/kg and the PBCD34+ count correlated with 6 month blood counts better than any subset of CD34+ cells or any clinical factor. The PBCD34+ count was overall a stronger predictor of 6 month blood counts than was the total CD34+ cells/kg infused. Both factors retained their significance in multivariate analysis, controlling for clinical factors. In conclusion, subsets of CD34+ cells and clinical factors are inferior to the total CD34+ cell dose/kg and PBCD34+ count in predicting 6 month blood counts following ASCT.
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Akamatsu CT, Stewart DA, Becker BJ. Documenting English syntactic development in face-to-face signed communication. AMERICAN ANNALS OF THE DEAF 2000; 145:452-463. [PMID: 11191824 DOI: 10.1353/aad.2012.0130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The authors explored the face-to-face English competence of five students who were participating in a larger study of teachers' use of English-based signing. Using case studies, the authors report on the students' development of English-based signing at the beginning and end of their involvement in this 4-year study. Grammatical forms similar in English and American Sign Language (ASL) were initially more readily produced when tested for in English, and showed consistently higher attainment levels across all the students, than grammatical forms that are different in English and ASL. The authors found emerging English forms that could be documented (a) between prompted and imitated utterances and (b) within blocks of test items examining the same grammatical constructions. The authors conclude that teachers' concerted efforts to use English-based signing as a language of instruction enhance deaf students' English acquisition. Such signing helps build a bridge between native sign language and the development of English skills necessary for literacy.
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Chen CT, Lin J, Li Q, Phipps SS, Jakubczak JL, Stewart DA, Skripchenko Y, Forry-Schaudies S, Wood J, Schnell C, Hallenbeck PL. Antiangiogenic gene therapy for cancer via systemic administration of adenoviral vectors expressing secretable endostatin. Hum Gene Ther 2000; 11:1983-96. [PMID: 11020798 DOI: 10.1089/10430340050143417] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
A growing number of antiangiogenesis strategies have been investigated for the treatment of cancer and other angiogenesis-dependent diseases. One of the most promising strategies is to systemically administer one or more antiangiogenic proteins frequently enough to achieve a sufficient long-term steady state level of the protein(s) to achieve the maximum beneficial effect. However, the utility of this strategy is limited because of many technical difficulties, including obtaining both the quantity and quality of the protein(s) necessary for optimal therapeutic benefit. To overcome these difficulties, we hypothesized that a single administration of a replication-defective adenoviral vector expressing a secretable antiangiogenic protein could achieve an optimal long-term systemic concentration. We constructed a recombinant adenoviral vector, Av3mEndo, which encodes a secretable form of murine endostatin. We demonstrated secretion of endostatin from several cell lines transduced with Av3mEndo. Partially purified endostatin secreted from Av3mEndo-transduced mammalian cells was shown to potently inhibit endothelial cell migration in vitro. A single intravenous administration of Av3mEndo in mice was shown to result in (1) prolonged and elevated levels of circulating endostatin, (2) partial inhibition of VEGF-induced angiogenesis in a VEGF implant angiogenesis model, and (3) prolonged survival and in 25% of mice the complete prevention of tumor growth in a prophylactic human colon/liver metastasis xenograft murine model. These results support our contention that adenoviral vector-mediated expression of an antiangiogenic protein(s) represents an attractive therapeutic approach to cancer and other angiogenesis-dependent diseases.
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MESH Headings
- Adenoviridae/genetics
- Amino Acid Sequence
- Animals
- Cell Line
- Cell Movement
- Cells, Cultured
- Collagen/blood
- Collagen/genetics
- Colonic Neoplasms/therapy
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Electrophoresis, Polyacrylamide Gel
- Endostatins
- Endothelial Growth Factors/antagonists & inhibitors
- Endothelium, Vascular/metabolism
- Enzyme-Linked Immunosorbent Assay
- Female
- Genetic Therapy/methods
- Genetic Vectors
- Humans
- Liver Neoplasms/therapy
- Lymphokines/antagonists & inhibitors
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Nude
- Models, Genetic
- Molecular Sequence Data
- Neoplasm Transplantation
- Neoplasms/therapy
- Neoplasms, Experimental/therapy
- Neovascularization, Pathologic/therapy
- Peptide Fragments/blood
- Peptide Fragments/genetics
- Polymerase Chain Reaction
- Time Factors
- Transduction, Genetic
- Tumor Cells, Cultured
- Umbilical Veins/metabolism
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
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Nash CL, Price LM, Stewart DA, Sepandj F, Yilmaz S, Barama A. Early gastric post-transplantation lymphoproliferative disorder and H pylori detection after kidney transplantation: a case report and review of the literature. CANADIAN JOURNAL OF GASTROENTEROLOGY = JOURNAL CANADIEN DE GASTROENTEROLOGIE 2000; 14:721-4. [PMID: 11185538 DOI: 10.1155/2000/135385] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The incidence of post-transplantation lymphoproliferative disorder (PTLD) in the adult renal transplant population ranges from 0.7% to 4%. The majority of cases involve a single site and arise, on average, seven months after transplantation. Histopathology usually reveals B-cell proliferative disease and has been standardized into its own classification. Treatment modalities consist of decreased immunosuppression, eradication of Epstein-Barr virus, surgical resection, systemic chemotherapy and monoclonal antibody therapy; however, mortality remains high, typically with a short survival time. In patients who have undergone renal transplantation, approximately 10% of those with PTLDs present with gastrointestinal symptomatology and disease. Reported sites include the stomach, and small and large bowel. Very few cases of Helicobacter pylori or mucosal-associated lymphoid tissue have been described in association with PTLD. In the era of cyclosporine immunosuppression, the incidence of PTLD affecting the gastrointestinal tract may be increasing in comparison with the incidence seen with the use of older immunosuppression regimens. A case of antral PTLD and H pylori infection occurring three months after renal transplantation is presented, and the natural history and management of gastric PTLD are reviewed.
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Stewart DA, Guo D, Glück S, Morris D, Chaudhry A, deMetz C, Klassen J, Brown CB, Russell JA. Double high-dose therapy for Hodgkin's disease with dose-intensive cyclophosphamide, etoposide, and cisplatin (DICEP) prior to high-dose melphalan and autologous stem cell transplantation. Bone Marrow Transplant 2000; 26:383-8. [PMID: 10982284 DOI: 10.1038/sj.bmt.1702541] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We previously reported a 50% (95% CI = 33-76%) 5 year event-free survival (EFS) rate for 23 patients with Hodgkin's disease (HD) who received salvage therapy with single agent high-dose melphalan (HDM) and autologous stem cell transplantation (ASCT). Predictors of poor outcome included bulky disease and initial remission <1 year. Since 1995, similar poor prognosis patients have been treated with double high-dose therapy consisting of dose-intensive cyclophosphamide 5.25 g/m2, etoposide 1.05 g/m2, cisplatin 105 mg/m2 (DICEP) for tumor cytoreduction and stem cell mobilization followed by HDM/ASCT. The purpose of the present study is to determine if the use of DICEP is associated with improved event-free (EFS) and overall survival (OAS) for patients treated with HDM/ASCT. From February 1981 to June 1999, 46 consecutive patients received HDM/ASCT for relapsed (n = 35) or refractory (n = 11) HD. DICEP re-induction and blood stem cell mobilization was used for 21 patients. Factors considered for univariate and multivariate analyses included age at transplant, number of failed chemotherapy regimens, prior radiotherapy, length of initial remission, relapsed or refractory disease status, extranodal relapse, B symptoms at relapse, bulk, post-ASCT radiotherapy, and DICEP re-induction therapy. Cox proportional hazards models were constructed for both event and death. DICEP and HDM were well tolerated with no early treatment-related mortality or toxicity requiring life-sustaining measures. For all 46 patients, the projected 5 year EFS was 52% (95% CI = 38-72%) and OAS was 57% (95% CI = 40-82). Factors independently associated with relapse in multivariate analysis included bulk >5 cm (RR = 6.38, P = 0.002), prior radiotherapy (RR = 3.59, P = 0.027), and not using DICEP (RR = 5.29, P = 0.005). Factors independently associated with death included bulk >5 cm (RR = 5.13, P = 0.009), > or =3 prior chemotherapy regimens (RR = 4.72, P = 0.019), and not using DICEP (RR = 7.49, P = 0.015). This study demonstrates that DICEP re-induction prior to HDM/ASCT is feasible. The preliminary data are sufficiently encouraging to warrant a multicenter phase II or a phase III trial evaluating DICEP followed by HDM/ASCT as salvage therapy for HD.
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Abstract
Outpatient high-dose chemotherapy and autologous stem cell transplantation (ASCT) has been shown to be feasible in terms of physical morbidity and mortality outcomes, but few data exist on the psychosocial impact of delivering such aggressive therapy in this manner. The purpose of this observational study was to compare effects of inpatient (n = 20) and outpatient (n = 21) modes of care on physical status, psychological well-being, quality of life, personal finances and caregiver burden. Most patients were treated according to their preference for inpatient or outpatient care. Those choosing outpatient care were screened for eligibility according to established criteria for ambulatory management. Measures were taken at baseline, then at days 4-6, 12-16 and 30 post ASCT. Results showed that overall, the psychological, physical, social and financial outcomes of the outpatient ASCT group were comparable, to or better than inpatients. Factors that seem to be important for successful outpatient management are previous experience with cancer treatment, a satisfying quality of life, physical well-being, patient's preference for a particular mode of care and physical proximity to the treatment centre. The study results suggest that outpatient ASCT is an efficient, effective and acceptable form of care for motivated patients and caregivers who have the physical and psychological capability and desire to receive cancer treatment in this manner.
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