Blind and naive classification of toxicity by fish chromatophores

Cellular and molecular pathways involved in the ability of animals to change color have been studied previously as biosensors and cytosensors of active and toxic agents, but such studies generally have been limited to just a few standardized agents. Here we describe the performance of cultured chromatophore pigment cells from the fin tissue of Siamese fighting fish as sensors of toxic agents under blind sampling conditions at the September 2002 EILATox-Oregon Workshop. Detection was accomplished by monitoring motor protein-mediated movements of cellular pigment in chromatophores at both the gross population level as well as in singly imaged cells. Pigment responses were recorded both during the exposure of chromatophores to each blind sample as well as afterwards when the cells were examined for after-effects by challenging them with clonidine, an adrenergic drug that induces standardized pigment movements. After recording all results and upon breaking the key to reveal the identities of the toxic agents, it was found that all of the toxic samples in the study had been distinguished accurately from non-toxic controls that were included among the blind samples. Furthermore, it was revealed that most of the toxic agents detected had never before been tested or calibrated against chromatophores, demonstrating that detection can be achieved under naive conditions that have not been optimized for the analysis of any particular toxic agent. Finally, by organizing the results into categories of pigment responses, a binary classification tree was generated that distinguished each toxic agent as having a distinct response pattern from the others. Thus, chromatophore-based cytosensors can discover toxicity in the absence of prior knowledge of the agent in question, and the categories of responses of the cells can be used to distinguish one toxic agent from another.     

Equity in resource allocation in the Irish health service. A policy Delphi study

Resource allocation in the Irish health service, based on historical allocations with incremental increases, is widely believed to be inequitable. Using a three-round policy Delphi survey, which seeks to explore both consensus and disagreement surrounding policy issues, the views of 52 senior health service personnel were sought in order to determine ways to improve equity in resource allocation. Panelists provided several reasons why the current method of resource allocation is inequitable and several suggestions for improving equity. The level of consensus on views was determined by calculating the percentage of ratings in each category based on a series of rating scales. The main suggestion centred around the development and implementation of a needs based resource allocation formula. Panelists reached a high consensus in favour of this but only reached a low consensus as to its feasibility. Potential obstacles identified included methodological difficulties, insufficient resources and resistance from potential losers. These findings highlight concerns about the lack of transparency in the resource allocation process and openness to the development of a more equitable needs based resource allocation model, a move which is becoming more common internationally. Feasibility concerns should not preclude an attempt to begin this process.     

21q22 balanced chromosome aberrations in therapy-related hematopoietic disorders: report from an international workshop

The International Workshop on the relationship between prior therapy and balanced chromosome aberrations in therapy-related myelodysplastic syndromes (t-MDS) and therapy-related acute leukemia (t-AL) identified 79 of 511 (15.5%) patients with balanced 21q22 translocations. Patients were treated for their primary disease, including solid tumors (56%), hematologic malignancy (43%), and juvenile rheumatoid arthritis (single case), by radiation therapy (5 patients), chemotherapy (36 patients), or combined-modality therapy (38 patients). 21q translocations involved common partner chromosomes in 81% of cases: t(8;21) (n = 44; 56%), t(3;21) (n = 16; 20%), and t(16;21) (n = 4; 5%). Translocations involving 15 other partner chromosomes were also documented with involvement of AML1(CBFA2/RUNX1), identifying a total of 23 different 21q22/AML1 translocations. The data analysis was carried out on the basis of five subsets of 21q22 cases, that is, t(8;21) with and without additional aberrations, t(3;21), t(16;21), and other 21q22 translocations. Dysplastic features were present in all 21q22 cases. Therapy-related acute myeloid leukemia (t-AML) at presentation was highest in t(8;21) (82%) and lowest in t(3;21) (37.5%) patients. Cumulative drug dose exposure scores for alkylating agents (AAs) and topoisomerase II inhibitors indicated that t(3;21) patients received the most intensive therapy among the five 21q22 subsets, and the median AA score for patients with secondary chromosome 7 aberrations was double the AA score for the entire 21q22 group. All five patients who received only radiation therapy had t(8;21) t-AML. The median latency and overall survival (OS) for 21q22 patients were 39 and 14 months (mo), compared to 26 and 8 mo for 11q23 patients, 22 and 28 mo for inv(16), 69 and 7 mo for Rare recurring aberrations, and 59 and 7 mo for Unique (nonrecurring) balanced aberration (latency P < or = 0.016 for all pairwise comparisons; OS, P < or = 0.018 for all pairwise comparisons). The percentages of 21q22 patients surviving 1 year, 2 years, and 5 years were 58%, 33%, and 18%, respectively. Noticeable differences were observed in median OS between 21q22 patients (n = 7) receiving transplant (BMT) (31 mo) compared to 21q22 patients who received intensive non-BMT therapy (n = 46) (17 mo); however, this was nonsignificant because of the small sample size (log-rank, P = 0.33). t-MDS/t-AML with balanced 21q22 aberrations was associated with prior exposure to radiation, epipodophyllotoxins, and anthracyclines, dysplastic morphologic features, multiple partner chromosomes, and longer latency periods when compared to 11q23 and inv(16) t-MDS/AML Workshop subgroups. In general, patients could be divided into two prognostic risk groups, those with t(8;21) (median OS, 19 mo) and those without t(8;21) (median OS, 7 mo) leukemia (log-rank, P = 0.0007).     

Rasburicase for the treatment and prevention of hyperuricemia

OBJECTIVE: To review the information currently available on rasburicase for treatment and prevention of hyperuricemia. DATA SOURCES: MEDLINE (1966-August 2002) was searched for primary and review articles. STUDY SELECTION/DATA EXTRACTION: Studies evaluating rasburicase, including abstracts and proceedings, were considered for inclusion. English-language literature was evaluated for the pharmacology, pharmacodynamics, pharmacokinetics, therapeutic use, and adverse effects of rasburicase. DATA SYNTHESIS: Rasburicase, a recombinant urate oxidase, has been shown to be effective in lowering uric acid and preventing uric acid accumulation in patients with hematologic malignancies who had hyperuricemia or who were at high risk for developing hyperuricemia. It has been approved for pediatric use in the US. CONCLUSIONS: In addition to allopurinol, hydration, and urinary alkalinization, rasburicase is a new alternative for the treatment and prevention of hyperuricemia in patients with hematologic malignancies. Its rapid onset of action and the ability to lower preexisting elevated uric acid levels are the advantages of rasburicase compared with allopurinol. It may allow the patient to receive chemotherapy treatment without delay.     

Technology evaluation: Onyvax-105, Onyvax

Onyvax, under license from the Cancer Research Campaign, is developing Onyvax-105 (105AD7), an anti-idiotype monoclonal antibody, for the potential treatment of colorectal cancer. Onyvax initiated phase II clinical trials in May 2000.