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1.
Sci Rep ; 14(1): 2958, 2024 Feb 05.
Article in English | MEDLINE | ID: mdl-38316798

ABSTRACT

During homogenisation of the AA3104 cast ingot, a phase transformation of intermetallic particles from ß-Al6(Fe,Mn) orthorhombic phase to harder α-Alx(Fe,Mn)3Si2 cubic phase occurs. The large constituent intermetallic particles, regardless of phase, assist in the recrystallisation nucleation process through particle stimulated nucleation (PSN). Ultimately, this helps to refine grain size. The sub-micron dispersoids act to impede grain boundary migration through a Zener drag mechanism. For this reason, the dispersoids that form during homogenisation are critical to the recrystallisation kinetics during subsequent rolling, with smaller dispersoids being better suited to instances where the minimisation of recrystallisation is required during hot rolling. This work simulates an industrial two-step homogenisation practice with variations in the peak temperature of the first step between 560 °C and 580 °C. The effect of this temperature variation on the intermetallic particle phase evolution is investigated. The aim is to identify the ideal intermetallic phase balance and the dispersoid structure that are best suited for the minimisation of recrystallisation during hot rolling through maximising Zener drag and maintaining galling resistance. The results indicate a trend where an increase in homogenisation temperature from 560 °C to 580 °C yields, firstly, an increase in the volume fraction of the α-phase particles to greater than 50% of the total volume fraction at both the edge and the centre of the ingot and, secondly, it yields an increased dispersoid size. Thus, a lower temperature homogenisation practice produces a near-ideal combination of intermetallic particle phase distribution, as well as dispersoid size, which is critical for Zener drag and the minimization of recrystallisation during the hot rolling processes.

2.
J Exp Clin Cancer Res ; 39(1): 78, 2020 May 06.
Article in English | MEDLINE | ID: mdl-32375866

ABSTRACT

The majority of high-risk neuroblastomas can be divided into three distinct molecular subgroups defined by the presence of MYCN amplification, upstream TERT rearrangements or alternative lengthening of telomeres (ALT). The common defining feature of all three subgroups is altered telomere maintenance; MYCN amplification and upstream TERT rearrangements drive high levels of telomerase expression whereas ALT is a telomerase independent telomere maintenance mechanism. As all three telomere maintenance mechanisms are independently associated with poor outcomes, the development of strategies to selectively target either telomerase expressing or ALT cells holds great promise as a therapeutic approach that is applicable to the majority of children with aggressive disease.Here we summarise the biology of telomere maintenance and the molecular drivers of aggressive neuroblastoma before describing the most promising therapeutic strategies to target both telomerase expressing and ALT cancers. For telomerase-expressing neuroblastoma the most promising targeted agent to date is 6-thio-2'-deoxyguanosine, however clinical development of this agent is required. In osteosarcoma cell lines with ALT, selective sensitivity to ATR inhibition has been reported. However, we present data showing that in fact ALT neuroblastoma cells are more resistant to the clinical ATR inhibitor AZD6738 compared to other neuroblastoma subtypes. More recently a number of additional candidate compounds have been shown to show selectivity for ALT cancers, such as Tetra-Pt (bpy), a compound targeting the telomeric G-quadruplex and pifithrin-α, a putative p53 inhibitor. Further pre-clinical evaluation of these compounds in neuroblastoma models is warranted.In summary, telomere maintenance targeting strategies offer a significant opportunity to develop effective new therapies, applicable to a large proportion of children with high-risk neuroblastoma. In parallel to clinical development, more pre-clinical research specifically for neuroblastoma is urgently needed, if we are to improve survival for this common poor outcome tumour of childhood.


Subject(s)
Neuroblastoma/therapy , Telomere/physiology , Cell Line, Tumor , Child, Preschool , Female , Humans , Infant , Male , Neuroblastoma/drug therapy , Neuroblastoma/genetics , Telomere/drug effects , Telomere/genetics , Telomere/metabolism
3.
Leukemia ; 25(5): 800-7, 2011 May.
Article in English | MEDLINE | ID: mdl-21321569

ABSTRACT

Untreated de novo (n=421) and secondary (n=189) acute myeloid leukemia (AML) patients ≥60 years received intensified chemotherapy, including daunorubicin 60 mg/m(2) and etoposide 100 mg/m(2) during days 1, 2, 3 with cytarabine 100 mg/m(2) during days 1-7, with a second induction if needed and one consolidation course with these drugs and doses for 2, 2 and 5 days, respectively. In all, 287 (47%) achieved complete remission (CR), 136 (22%) died and 187 (31%) were non-responders. CR rates were 27, 44 and 52% for complex karyotypes, rare aberrations and neither (P<0.001), 52 and 37% for de novo and secondary AML (P=0.003), and 53 and 42% for age 60-69 and ≥70 years (P=0.015). In multivariable analysis, CR predictors included non-complex/non-rare karyotypes (P<0.001), de novo AML (P<0.001), better performance status (PS) (P<0.001) and younger age (P=0.001). Disease-free (DFS) and overall (OS) survival medians were 6.8 (95% CI: 6.2, 7.8) and 7.2 (95% CI: 6.4, 8.6) months. In multivariable analysis, DFS was shorter for complex karyotypes (P<0.001) and increasing white blood count (WBC) (P<0.001) and age (P=0.038), and OS for complex karyotypes (P<0.001), increasing WBC (P=0.001) and age (P<0.001), poorer PS (P<0.001) and secondary AML (P=0.010). Outcomes and prognostic factors were similar to those in previous Cancer and Leukemia Group B studies.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Leukemia, Myeloid, Acute/drug therapy , Aged , Aged, 80 and over , Cytarabine/therapeutic use , Daunorubicin/therapeutic use , Etoposide/therapeutic use , Female , Humans , Karyotyping , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/mortality , Male , Middle Aged , Remission Induction , Survival Rate , Treatment Outcome
6.
Disabil Rehabil ; 24(16): 860-6, 2002 Nov 10.
Article in English | MEDLINE | ID: mdl-12450462

ABSTRACT

BACKGROUND: Most stroke-related studies have consisted of people over the age of 65. This study examined the unmet needs of young people with stroke, living in community housing in the UK. METHOD: People with a stroke (>1 year ago), in two age bands (18-45; 46-65) were sent the Southampton Needs Assessment Questionnaire for people with Stroke. RESULTS: 315 out of 639 (49%) questionnaires were returned (mean age 55, SD 9; 189 males, 126 females). The median number of unmet needs reported was two (IQR 0-6). The most frequently reported unmet needs were: provision of information about the responders' stroke (45%); assistance with finances (24%); non-care activities (19%); and intellectual fulfillment (17%). Responders in the younger age group reported significantly more unmet needs than responders in the older age group (for a holiday, intellectual fulfillment and family support). Responders with poor mobility reported significantly more unmet needs than responders with average and good mobility for 15 unmet needs (three most pressing: respite care/short breaks; adaptations; and access to community environment). Responders who did not return to work reported significantly more unmet needs than responders who had reduced hours or changed jobs and people who returned to the same job with the same hours for seven unmet needs (three most pressing: help with finances; a holiday and speech therapy). CONCLUSION: People of younger age, with poorer mobility and those unable to return to work, report most unmet needs. Further work needs to be done within the community, with employers and professionals, in relation to education and the provision of specifically targeted information in order to facilitate participation and autonomy for people with stroke.


Subject(s)
Stroke Rehabilitation , Adolescent , Adult , Aged , Employment , Female , Humans , Male , Middle Aged , Social Support , Statistics, Nonparametric , United Kingdom
7.
Cancer Res ; 61(19): 7233-9, 2001 Oct 01.
Article in English | MEDLINE | ID: mdl-11585760

ABSTRACT

The FLT3 gene is mutated by an internal tandem duplication (ITD) in 20-25% of adults with acute myeloid leukemia (AML). We studied 82 adults <60 years of age with primary AML and normal cytogenetics, who received uniform high-dose therapy and found FLT3 ITD in 23 (28%) patients. When the 23 FLT3 ITD+ cases were compared with the 59 cases with wild-type (WT) FLT3, disease-free survival (DFS) was inferior (P = 0.03), yet overall survival (OS) was not different (P = 0.14). However, 8 (35%) of 23 FLT3 ITD/+ cases also lacked a FLT3 WT allele (FLT3(ITD-R)) as determined by PCR and loss of heterozygosity. Thus, three genotypic groups were identified: normal FLT3(WT/WT), heterozygous FLT3(ITD/WT), and hemizygous FLT3(ITD/-). DFS and OS were significantly inferior for patients with FLT3(ITD/-) (P = 0.0017 and P = 0.0014, respectively). Although DFS and OS for FLT3(WT/WT) and FLT3(ITD/WT) groups did not differ (P = 0.32 and P = 0.98, respectively), OS of the FLT3(ITD/-) group was worse than the FLT3(WT/WT) (P = 0.0005) and FLT3(ITD/WT) (P = 0.008) groups. We propose a model in which FLT3(ITD/-) represents a dominant positive, gain-of-function mutation providing AML cells with a greater growth advantage compared with cells having the FLT3(WT/WT) or FLT3(ITD/WT) genotypes. In conclusion, we have identified the FLT3(ITD/-) genotype as an adverse prognostic factor in de novo AML with normal cytogenetics. A poor prognosis of the relatively young FLT3(ITD/-) adults (median age, 37 years), despite treatment with current dose-intensive regimens, suggests that new treatment modalities, such as therapy with a FLT3 tyrosine kinase inhibitor, are clearly needed for this group of patients.


Subject(s)
Gene Duplication , Leukemia, Myeloid/genetics , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Acute Disease , Adult , Alleles , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Clinical Trials, Phase I as Topic , Clinical Trials, Phase II as Topic , Disease-Free Survival , Female , Humans , Karyotyping , Leukemia, Myeloid/drug therapy , Male , Middle Aged , Mutation , Tandem Repeat Sequences , Treatment Outcome , fms-Like Tyrosine Kinase 3
8.
N Engl J Med ; 345(10): 707-14, 2001 Sep 06.
Article in English | MEDLINE | ID: mdl-11547739

ABSTRACT

BACKGROUND: Previous studies have suggested that people with human immunodeficiency virus (HIV) infection who are coinfected with GB virus C (GBV-C, or hepatitis G virus) have delayed progression of HIV disease. GBV-C is related to hepatitis C virus but does not appear to cause liver disease. METHODS: We examined the effect of coinfection with GBV-C on the survival of patients with HIV infection. We also evaluated cultures of peripheral-blood mononuclear cells infected with both viruses to determine whether GBV-C infection alters replication in vitro. RESULTS: Of 362 HIV-infected patients, 144 (39.8 percent) had GBV-C viremia in two tests. Forty-one of the patients with GBV-C viremia (28.5 percent) died during the follow-up period, as compared with 123 of the 218 patients who tested negative for GBV-C RNA (56.4 percent; P<0.001). The mean duration of follow-up for the entire cohort was 4.1 years. In a Cox regression analysis adjusted for HIV treatment, baseline CD4+ T-cell count, age, sex, race, and mode of transmission of HIV, the mortality rate among the 218 HIV-infected patients without GBV-C coinfection was significantly higher than that among the 144 patients with GBV-C coinfection (relative risk, 3.7; 95 percent confidence interval, 2.5 to 5.4). HIV replication, as measured by the detection of p24 antigen in culture supernatants, was reproducibly inhibited in cultures of peripheral-blood mononuclear cells by GBV-C coinfection. Coinfection did not alter the surface expression of HIV cellular receptors on peripheral-blood mononuclear cells, as determined by flow cytometry. CONCLUSIONS: GBV-C infection is common in people with HIV infection and is associated with significantly improved survival.


Subject(s)
Flaviviridae , HIV Infections/mortality , Hepatitis, Viral, Human/complications , Adult , CD4 Lymphocyte Count , Cells, Cultured , Chi-Square Distribution , Female , Flaviviridae/genetics , Flaviviridae/growth & development , Flaviviridae/isolation & purification , Follow-Up Studies , HIV/growth & development , HIV/isolation & purification , HIV Infections/complications , Humans , Leukocytes, Mononuclear , Male , Proportional Hazards Models , RNA, Viral/analysis , Receptors, HIV , Survival Analysis , Viremia , Virus Replication
9.
Blood ; 98(3): 548-53, 2001 Aug 01.
Article in English | MEDLINE | ID: mdl-11468148

ABSTRACT

The treatment of older patients with acute myeloid leukemia (AML) remains unsatisfactory, with complete remission (CR) achieved in only approximately 50% and long-term disease-free survival in 10% to 20%. Three hundred eighty-eight patients (60 years of age and older) with newly diagnosed de novo AML were randomly assigned to receive placebo (P) or granulocyte-macrophage colony-stimulating factor (GM-CSF) or GM in a double-blind manner, beginning 1 day after the completion of 3 days of daunorubicin and 7 days of cytarabine therapy. No differences were found in the rates of leukemic regrowth, CR, or infectious complications in either arm. Of 205 patients who achieved CR, 169 were medically well and were randomized to receive cytarabine alone or a combination of cytarabine and mitoxantrone. With a median follow-up of 7.7 years, the median disease-free survival times were 11 months and 10 months for those randomized to cytarabine or cytarabine/mitoxantrone, respectively. Rates of relapse, excluding deaths in CR, were 77% for cytarabine and 82% for cytarabine/mitoxantrone. Induction randomization had no effect on leukemic relapse rate or remission duration in either postremission arm. Because cytarabine/mitoxantrone was more toxic and no more effective than cytarabine, it was concluded that this higher-dose therapy had no benefit in the postremission management of older patients with de novo AML. These results suggest the need to develop novel therapeutic strategies for these patients. (Blood. 2001;98:548-553)


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Cytarabine/administration & dosage , Leukemia, Myeloid/drug therapy , Actuarial Analysis , Acute Disease , Aged , Cytarabine/standards , Cytarabine/toxicity , Disease-Free Survival , Dose-Response Relationship, Drug , Double-Blind Method , Follow-Up Studies , Humans , Leukemia, Myeloid/complications , Middle Aged , Mitoxantrone/administration & dosage , Mitoxantrone/standards , Mitoxantrone/toxicity , Remission Induction , Survival Rate , Time Factors , Treatment Outcome
10.
Cancer ; 91(8): 1444-50, 2001 Apr 15.
Article in English | MEDLINE | ID: mdl-11301391

ABSTRACT

BACKGROUND: The authors tested the hypothesis that children with a longer duration of symptoms prior to diagnosis of medulloblastoma have more advanced disease. In addition, they evaluated whether there are correlations between gender, duration of presenting symptoms, and disease stage. METHODS: The study population consisted of 122 patients with medulloblastoma who were evaluated between 1974 and 1999. The data abstracted from each chart included the date of diagnosis, date of birth, gender, race, presenting symptoms, duration of symptoms in weeks, and disease stage. RESULTS: There were 70 males (57%) and 52 females (43%); 105 Caucasians (86%), 16 non-Caucasians (13%), and 1 patient of unknown race. Eighteen percent of the patients were age < or = 3 years, 59% were ages 4-16 years, and 23% were age > or = 17 years. The presenting stage was determined in 108 patients. Thirty-eight patients (35%) had high stage disease (T1-T4 M1-M4), and 70 patients (65%) had low stage disease (T1-T4 M0). The most common presenting symptoms were emesis (68%), headache (66%), nausea (40%), and ataxia (40%). The median symptom durations for patients ages 0-3 years were 4 weeks and 8 weeks for both those ages 4-16 years and those age > or = 17 years, respectively (P > 0.11). The median symptom duration for males (8 weeks) was longer than for females (5 weeks; P = 0.08). Patients with low stage disease had a median duration of symptoms (8 weeks) that was significantly greater compared with patients with high stage disease (4 weeks; P = 0.01). Relating patient age to disease stage, 47% of patients ages 0-3 years had high stage disease; 36% of patients ages 4-16 years had high stage disease; and 24% of patients age > or = 17 years had high stage disease (P = 0.20). Relating disease stage to gender, 40% of males had high stage disease compared with 28% of females (P = 0.20). Of the factors age, gender, race, and duration of symptoms, only the later was correlated significantly with disease stage at the time of presentation in both univariate and multivariate analyses. CONCLUSIONS: Contrary to expectations, the duration of presenting symptoms was correlated inversely with disease state at the time of presentation. This finding has implications for lawsuits alleging that a "delay in diagnosis" leads to more advanced disease. There is weak evidence (P = 0.08) that males have a longer duration of symptoms than females. This may be related to gender-associated behavior expectations.


Subject(s)
Cerebellar Neoplasms/pathology , Medulloblastoma/pathology , Neoplasm Staging , Adolescent , Adult , Ataxia/etiology , Cerebellar Neoplasms/diagnosis , Child , Child, Preschool , Diagnosis, Differential , Female , Headache/etiology , Humans , Infant , Infant, Newborn , Male , Medulloblastoma/diagnosis , Nausea/etiology , Prognosis , Retrospective Studies , Severity of Illness Index , Sex Factors , Time Factors , Vomiting/etiology
11.
Stat Med ; 20(2): 193-213, 2001 Jan 30.
Article in English | MEDLINE | ID: mdl-11169597

ABSTRACT

This paper considers several permutation tests for treatment-by-centre interaction in multi-centre clinical trials in which the endpoint is survival time subject to censoring. Some of the tests are based on existing tests and some are new. To evaluate and compare the tests with respect to power under different conditions, we generated survival times and censoring times through simulation. We used special methodology to handle the unusual problems that arise in power simulations when the tests under study are permutation tests. Different conditions yielded different interaction tests as the best performers. Although one test gave comparatively good power under almost all conditions, some of the other tests also appear to be useful. For the sample sizes and configurations in the simulations, power is generally low; thus it may not be possible to detect interaction reliably when it exists, a finding in agreement with the known low power for interaction tests in general.


Subject(s)
Computer Simulation , Multicenter Studies as Topic/methods , Randomized Controlled Trials as Topic/methods , Statistics as Topic/methods , Aged , Antineoplastic Agents, Alkylating/pharmacology , Aziridines/pharmacology , Benzoquinones/pharmacology , Brain Neoplasms/drug therapy , Carmustine/pharmacology , Glioma/drug therapy , Granulocyte-Macrophage Colony-Stimulating Factor/pharmacology , Humans , Leukemia, Myeloid/drug therapy , Remission Induction
12.
Control Clin Trials ; 21(5): 415-27, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11018560

ABSTRACT

The characteristics of scientific fraud and its impact on medical research are in general not well known. However, the interest in the phenomenon has increased steadily during the last decade. Biostatisticians routinely work closely with physicians and scientists in many branches of medical research and have therefore unique insight into data. In addition, they have methodological competence to detect fraud and could be expected to have a professional interest in valid results. Biostatisticians therefore are likely to provide reliable information on the characteristics of fraud in medical research. The objective of this survey of biostatisticians, who were members of the International Society for Clinical Biostatistics, was to assess the characteristics of fraud in medical research. The survey was performed between April and July 1998. The participation rate was only 37%. We report the results because a majority (51%) of the participants knew about fraudulent projects, and many did not know whether the organization they work for has a formal system for handling suspected fraud or not. Different forms of fraud (e.g., fabrication and falsification of data, deceptive reporting of results, suppression of data, and deceptive design or analysis) had been observed in fairly similar numbers. We conclude that fraud is not a negligible phenomenon in medical research, and that increased awareness of the forms in which it is expressed seems appropriate. Further research, however, is needed to assess the prevalence of different types of fraud, as well as its impact on the validity of results published in the medical literature.


Subject(s)
Biometry , Research , Scientific Misconduct , Data Collection , Scientific Misconduct/trends
13.
Br J Cancer ; 83(7): 959-63, 2000 Oct.
Article in English | MEDLINE | ID: mdl-10970702

ABSTRACT

Health Related Quality of Life (HRQoL) instruments are increasingly important in evaluating health care, especially in cancer trials. When planning a trial, one essential step is the calculation of a sample size, which will allow a reasonable chance (power) of detecting a pre-specified difference (effect size) at a given level of statistical significance. It is almost mandatory to include this calculation in research protocols. Many researchers quote means and standard deviations to determine effect sizes, and assume the data will have a Normal distribution to calculate their required sample size. We have investigated the distribution of scores for two commonly used HRQoL instruments completed by lung cancer patients, and have established that scores do not have the Normal distribution form. We demonstrate that an assumption of Normality can lead to unrealistically sized studies. Our recommendation is to use a technique that is based on the fact that the HRQoL data are ordinal and makes minimal but realistic assumptions.


Subject(s)
Quality of Life , Randomized Controlled Trials as Topic/methods , Statistics as Topic/methods , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carcinoma, Small Cell/drug therapy , Cyclophosphamide/administration & dosage , Etoposide/administration & dosage , Humans , Lung Neoplasms/drug therapy , Methotrexate/administration & dosage , Normal Distribution , Sample Size , Surveys and Questionnaires , Vincristine/administration & dosage
14.
Stat Med ; 18(24): 3435-51, 1999 Dec 30.
Article in English | MEDLINE | ID: mdl-10611617

ABSTRACT

Recent cases of fraud in clinical trials have attracted considerable media attention, but relatively little reaction from the biostatistical community. In this paper we argue that biostatisticians should be involved in preventing fraud (as well as unintentional errors), detecting it, and quantifying its impact on the outcome of clinical trials. We use the term 'fraud' specifically to refer to data fabrication (making up data values) and falsification (changing data values). Reported cases of such fraud involve cheating on inclusion criteria so that ineligible patients can enter the trial, and fabricating data so that no requested data are missing. Such types of fraud are partially preventable through a simplification of the eligibility criteria and through a reduction in the amount of data requested. These two measures are feasible and desirable in a surprisingly large number of clinical trials, and neither of them in any way jeopardizes the validity of the trial results. With regards to detection of fraud, a brute force approach has traditionally been used, whereby the participating centres undergo extensive monitoring involving up to 100 per cent verification of their case records. The cost-effectiveness of this approach seems highly debatable, since one could implement quality control through random sampling schemes, as is done in fields other than clinical medicine. Moreover, there are statistical techniques available (but insufficiently used) to detect 'strange' patterns in the data including, but no limited to, techniques for studying outliers, inliers, overdispersion, underdispersion and correlations or lack thereof. These techniques all rest upon the premise that it is quite difficult to invent plausible data, particularly highly dimensional multivariate data. The multicentric nature of clinical trials also offers an opportunity to check the plausibility of the data submitted by one centre by comparing them with the data from all other centres. Finally, with fraud detected, it is essential to quantify its likely impact upon the outcome of the clinical trial. Many instances of fraud in clinical trials, although morally reprehensible, have a negligible impact on the trial's scientific conclusions.


Subject(s)
Biometry , Clinical Trials as Topic/statistics & numerical data , Fraud/prevention & control , Scientific Misconduct/statistics & numerical data , Humans , Quality Control , Reproducibility of Results
15.
J Clin Oncol ; 17(9): 2831-9, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10561359

ABSTRACT

PURPOSE: The Cancer and Leukemia Group B conducted parallel phase I trials of cytarabine, daunorubicin, and etoposide (ADE) with or without PSC-833 (P), a modulator of p-glycoprotein-mediated multidrug resistance. PATIENTS AND METHODS: One hundred ten newly diagnosed patients > or = 60 years of age with de novo acute myeloid leukemia (AML) were treated. All patients received cytarabine by continuous infusion for 7 days at 100 mg/m(2)/d. The starting dose of daunorubicin was 30 mg/m(2)/d for 3 days. Etoposide was administered at a dose of 100 mg/m(2)/d for 3 days, except in the last cohort administered ADEP, who received 60 mg/m(2). PSC-833 was given intravenously with a loading dose of 1.5 mg/kg over 2 hours and a simultaneous continuous infusion of 10 mg/kg/d continued until 24 hours after the last dose of daunorubicin or etoposide. RESULTS: There was no toxicity attributed to the PSC-833. Dose-limiting toxicity was primarily gastrointestinal (diarrhea, mucositis in the ADEP group). The estimated maximum-tolerated doses, calculated using a logistic regression model, were daunorubicin 40 mg/m(2)/d for 3 days with etoposide 60 mg/m(2) for 3 days in the ADEP group and daunorubicin 60 mg/m(2)/d for 3 days and etoposide 100 mg/m(2)/d for 3 days in the ADE group. Twenty-one (48%) of 44 patients achieved complete remission with ADE, compared with 29 (44%) of 66 patients treated with ADEP. CONCLUSION: It is necessary to decrease the doses of daunorubicin and etoposide when they are administered with PSC-833, presumably because of the effect of the modulator on the pharmacokinetics of these agents. A phase III trial comparing the regimens derived from this phase I trial has recently begun.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Cyclosporins/administration & dosage , Leukemia, Myeloid/drug therapy , Acute Disease , Aged , Aged, 80 and over , Cyclosporins/adverse effects , Cytarabine/administration & dosage , Cytarabine/adverse effects , Daunorubicin/administration & dosage , Daunorubicin/adverse effects , Drug Resistance, Neoplasm , Etoposide/administration & dosage , Etoposide/adverse effects , Female , Humans , Male , Middle Aged
16.
Int J Hyperthermia ; 15(5): 383-98, 1999.
Article in English | MEDLINE | ID: mdl-10519690

ABSTRACT

In this study, whole body hyperthermia (WBH) was assessed as a means of heating intracranial tumours uniformly. Twenty-five dogs received radiation therapy and 20 the combination of radiation and WBH. Total radiation dose was randomly assigned and was either 44, 48, 52, 56 or 60 Gy. Because of WBH toxicity, intercurrent disease or tumour progression, seven of the 45 dogs received less than the prescribed radiation dose. For WBH, the target rectal temperature was 42 degrees C for 2h and three treatments were planned. In five of the 20 dogs randomized to receive WBH, only one WBH treatment was given because of toxicity. WBH toxicity was severe in six dogs, and resulted in death or interruption in treatment. Most tumours did not undergo a complete response, making it impossible to differentiate tumour recurrence from brain necrosis as a cause of progressive neuropathy. Therefore, survival was the major study endpoint. There was no survival difference between groups. One-year survival probability (95% CI) for dogs receiving radiation therapy alone was 0.44 (0.25, 0.63) versus 0.40 (0.19, 0.63) for dogs receiving radiation and WBH. There was no difference in the incidence of brain necrosis in the two treatment groups. Results suggest that use of WBH alone to increase the temperature of intracranial tumours as a means to improve radiation therapy outcome is not a successful strategy.


Subject(s)
Brain Neoplasms/veterinary , Dog Diseases/therapy , Hyperthermia, Induced , Animals , Brain Neoplasms/radiotherapy , Brain Neoplasms/therapy , Combined Modality Therapy , Dog Diseases/radiotherapy , Dogs , Hyperthermia, Induced/adverse effects , Radiotherapy Dosage , Survival Analysis , Temperature
17.
Control Clin Trials ; 20(5): 395-407, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10503800

ABSTRACT

Most large randomized clinical trials have a data monitoring committee that periodically examines efficacy and safety results. A typical data monitoring committee meets every 6 months, but the interim monitoring guidelines for many trials specify formal analyses that are years apart. In this article we argue that study protocols should include monitoring guidelines with formal looks at each data monitoring committee meeting. Such guidelines are shown to reduce the average duration of a trial with negligible effect on power and estimation bias. Some of the common statistical monitoring guidelines require extreme evidence to stop a trial early and do not distinguish between stopping a trial during active accrual and follow-up stages. We propose practical solutions for these issues.


Subject(s)
Randomized Controlled Trials as Topic/methods , Bayes Theorem , Data Interpretation, Statistical , Guidelines as Topic , Humans , Professional Staff Committees , Randomized Controlled Trials as Topic/standards , Randomized Controlled Trials as Topic/statistics & numerical data
20.
J Gen Intern Med ; 13(11): 753-6, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9824521

ABSTRACT

OBJECTIVE: To describe the current policies regarding statistical review of clinical research in biomedical journals. DESIGN: Cross-sectional survey. PARTICIPANTS: Editors of biomedical journals that publish original clinical research. MEASUREMENTS: General policies on statistical review, types of persons used for statistical reviewing, compensation of statistical reviewers, percentage of articles subject to such review, percentage of time statistical review makes an important difference, journal circulation, and selectivity. MAIN RESULTS: Of 171 journals, 114 (67%) responded to the survey. About one third of journals had policies that guaranteed statistical review for all accepted manuscripts. In approximately half of the journals, articles were sent for statistical review at the discretion of the editor. There was some evidence that statistical review policies differed between journals of different circulation size. In journals in the top quartile of circulation (> 25,000) the probability of definitely having a statistical review before an acceptance decision was 52%, but it was only 27% in journals in the lower three quartiles (p = .09). The probability of a statistical consultant on staff ranged from 31% in the bottom quarter, to 58% in the middle two, to 82% in the highest quarter (p < .001). Editors judged that statistical review resulted in an important change in a manuscript about half of the time. CONCLUSIONS: Except in the largest circulation medical journals, the probability of formal methodologic review of original clinical research is fairly low. As readers and researchers depend on the journals to assess the validity of the statistical methods and logic used in published reports, this is potentially a serious problem. This situation may exist because the cost of such statistical review can be considerable, and because finding appropriate reviewers can be difficult. It may also exist partly because editors or publishers may not regard such review as important. The professions of medical publishing, statistics, epidemiology, and other quantitative disciplines should work together to address this problem.


Subject(s)
Periodicals as Topic/standards , Publishing/standards , Statistics as Topic , Cross-Sectional Studies , Humans , Linear Models , Peer Review, Research/standards , Surveys and Questionnaires
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