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Group Protocol (group + protocol)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Artificial and bioartificial support systems for liver failure: a Cochrane Hepato-Biliary Group Protocol

LIVER INTERNATIONAL, Issue 5 2002
Jianping Liu
Abstract: Aims/Background: Liver support systems may bridge patients to liver transplantation or recovery from liver failure. This review is to evaluate the beneficial and harmful effects of artificial and bioartificial support systems for acute and acute-on-chronic liver failure. Data Sources: Randomized trials on any support system versus standard medical therapy will be included irrespective of publication status or language. Non-randomized studies are included in explorative analyses. Trials will be identified through bibliographies, correspondence with original investigators, and electronic searches (Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Controlled Trials Register, MEDLINE, EMBASE, and The Chinese Biomedical Database). Methods of the review: The extracted data will include characteristics of trials, patients, interventions, and all outcome measures. Methodological quality will be assessed by the randomization, follow up, and blinding. The RevMan and STATA will be used for statistical analyses. Sources of heterogeneity and methodological quality in the assessment of the primary outcome will be explored by sensitivity analyses and meta-regression. [source]

A hierarchical modelling approach to analysing longitudinal data with drop-out and non-compliance, with application to an equivalence trial in paediatric acquired immune deficiency syndrome

JOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 1 2002
Joseph W Hogan
Longitudinal clinical trials with long follow-up periods almost invariably suffer from a loss to follow-up and non-compliance with the assigned therapy. An example is protocol 128 of the AIDS Clinical Trials Group, a 5-year equivalency trial comparing reduced dose zidovudine with the standard dose for treatment of paediatric acquired immune deficiency syndrome patients. This study compared responses to treatment by using both clinical and cognitive outcomes. The cognitive outcomes are of particular interest because the effects of human immunodeficiency virus infection of the central nervous system can be more acute in children than in adults. We formulate and apply a Bayesian hierarchical model to estimate both the intent-to-treat effect and the average causal effect of reducing the prescribed dose of zidovudine by 50%. The intent-to-treat effect quantifies the causal effect of assigning the lower dose, whereas the average causal effect represents the causal effect of actually taking the lower dose. We adopt a potential outcomes framework where, for each individual, we assume the existence of a different potential outcomes process at each level of time spent on treatment. The joint distribution of the potential outcomes and the time spent on assigned treatment is formulated using a hierarchical model: the potential outcomes distribution is given at the first level, and dependence between the outcomes and time on treatment is specified at the second level by linking the time on treatment to subject-specific effects that characterize the potential outcomes processes. Several distributional and structural assumptions are used to identify the model from observed data, and these are described in detail. A detailed analysis of AIDS Clinical Trials Group protocol 128 is given; inference about both the intent-to-treat effect and average causal effect indicate a high probability of dose equivalence with respect to cognitive functioning. [source]

MDM2 polymorphism increases susceptibility to childhood acute myeloid leukemia: A report from the Children's Oncology Group,

PEDIATRIC BLOOD & CANCER, Issue 2 2010
Christine L. Phillips MD
Abstract Background The variant polymorphism in the gene MDM2, SNP309, leads to increased level of mdm2 protein and subsequent downregulation of p53 tumor suppressor pathway. Presence of this single nucleotide polymorphism (SNP) has been associated with earlier tumorigenesis in patients with Li,Fraumeni syndrome, as well as decreased survival in patients with CLL. In addition, cells homozygous (G/G) for SNP 309 were found to have 10-fold increase resistance to topoisomerase II inhibitors in vitro. Procedure We genotyped children (n,=,575) with de novo acute myeloid leukemia (AML) treated on three Children's Oncology Group protocols (CCG 2941/2961/AAML 03P1) for the presence of SNP309. Healthy blood donors were genotyped as control population. Results The variant G/G genotype was associated with an increased susceptibility to AML (OR 1.5; P,=,0.049). However, the presence of the variant allele at SNP309 did not modify disease response or toxicity in children treated on CCG protocols 2941/2961. Conclusions The variant SNP 309 influences susceptibility to pediatric AML, but does not impact overall response to therapy. Pediatr Blood Cancer. 2010;55:248,253. © 2010 Wiley,Liss, Inc. [source]

WT1 expression at diagnosis does not predict survival in pediatric aml: A report from the Children's Oncology Group

PEDIATRIC BLOOD & CANCER, Issue 6 2009
Suzie A. Noronha MD
Abstract WT1 is a transcription factor that is aberrantly overexpressed in acute and chronic leukemias. Overexpression of WT1 in pediatric acute myeloid leukemia has been reported, but the prognostic significance is unclear because sample sizes in these studies have been relatively small. WT1 expression was measured by quantitative RT-PCR in samples obtained at diagnosis from 155 pediatric AML patients treated on a cooperative group protocol. Neither overall survival nor event-free survival was correlated with WT1 expression. Pediatr Blood Cancer 2009;53:1136,1139. © 2009 Wiley-Liss, Inc. [source]