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Biomedical subjects

Christopher Arthur

Publications and source records attributed to Christopher Arthur.

4 recordsLinked to original sources
PubMed2005

Inflatable rescue boat-related injuries in Queensland surf lifesavers: the epidemiology - biomechanics interface.

The objective was to describe the relationship between epidemiological and biomechanical factors in the causal pathway of inflatable rescue boat (IRB)-related injuries in Australian surf lifesavers; to develop epidemiological and biomechanical methodologies and measurement instruments that identify and measure the risk factors, for use in future epidemiological studies. Epidemiological and biomechanical models of injury causation were combined. Host, agent and environmental factors that influenced total available force for transfer to host were specified. Measurement instruments for each of the specified risk factors were developed. Instruments were piloted in a volunteer sample of surf lifesavers. Participant characteristics were recorded using demographic questionnaires; IRB operating techniques were recorded using a custom-made on-board camera (Grand RF-Guard) and images of operating techniques were coded by two independent observers. Ground reaction forces transmitted to the host through the lifesaver's feet at the time of wave impact were measured using a custom-built piezoelectric force platform. The demographic questionnaire was found practical; the on-board camera functioned successfully within the target environment. Agreement between independent coders of IRB operating technique images was significant (p < 0.001) with Kappa values ranging from 0.5 to 0.7. Biomechanical instruments performed successfully in the target environment. Peak biomechanical forces were 415.6N (left foot) and 252.9N (right foot). This study defines the relationship between epidemiological and biomechanical factors in modifying the risk of IRB-related injury in a population of surf lifesavers. Preliminary feasibility of combining epidemiological and biomechanical information has been demonstrated. Further testing of the proposed model and measurement instruments is required.

Acceleration↗
PubMed2004

A randomized trial of high-versus conventional-dose cytarabine in consolidation chemotherapy for adult de novo acute myeloid leukemia in first remission after induction therapy containing high-dose cytarabine.

The value of administering sequential courses of chemotherapy containing high-dose cytarabine in both induction and consolidation therapy for acute myeloid leukemia (AML) has not been assessed in a prospective randomized trial. Two hundred ninety-two AML patients aged 15 to 60 years were enrolled in the Australasian Leukaemia and Lymphoma Group (ALLG) AML trial number 7 (M7) protocol to evaluate this question. All received induction therapy with the ICE protocol (idarubicin 9 mg/m2 x 3; cytarabine 3 g/m2 twice a day on days 1, 3, 5, 7; etoposide 75 mg/m2 x 7). Complete remission was achieved in 234 (80%) patients. Two hundred two patients in remission were then randomized to either a further identical cycle of ICE or 2 attenuated courses (cytarabine 100 mg/m2 daily x 5, idarubicin x 2, etoposide x 5 [IcE]). ICE consolidation therapy was more toxic than IcE, however, the treatment-related death rate was not significantly different. There was no difference between the 2 consolidation arms for relapse-free survival at 3 years (49% for ICE vs 46% for IcE; P = .66), survival following randomization (61% vs 62%; P = .91), or the cumulative incidence of relapse (43% vs 51%; P = .31), and there was no difference within cytogenetic risk groups. Intensive induction chemotherapy incorporating high-dose cytarabine results in high complete remission rates, but further intensive consolidation treatment does not appear to confer additional benefit.

Acute Disease↗
PubMed2003

Development of an immunosensor based on pressure transduction.

Traditional strategies for signal transduction in immunosensors are based on piezoelectric, thermometric, electrochemical, magnetic and optical methods. The use of pressure as a signal transduction method in immunosensors has not been reported previously. An immunosensor incorporating the detection of a change in pressure as the signal-transducing mechanism was investigated. A commercially available ultra-low pressure sensor was used in conjunction with a sealed chamber to assess the feasibility of this strategy. A key feature of the current approach is the use of a thin membrane (or film) in which to perform an immunoassay and subsequently to detect production of gas. The thinness contributes to efficient gas evolution and minimizes the effect of liquid acting as a "sink" for gas molecules. This feature also simplifies measurement of evolved gas, which traditionally was based on the use of bulk solutions, shaking and pH changes to "release" dissolved gas (especially carbon dioxide). Gas generation in the current approach is achieved by the coupling of catalase to haptens or antibodies for use in competitive or sandwich immunoassays, respectively. Hydrogen peroxide is used as the substrate. Performance characteristics of the sensor apparatus were assessed in several ways. Injection of various volumes of air from a gas-tight syringe produced an essentially linear relationship from 0.2 to 2.0 microl of injected volume, with a slope of approximately 5 V/microl. Depending on the duration of the sampling period, specific signals in excess of 2 V have been obtained for 0.01 units of catalase (approximately 0.4 ng of protein). Development and use of this sensing apparatus will be described for both competitive and sandwich immunoassays.

Aflatoxins↗