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Biomedical subjects

B Kirk

Publications and source records attributed to B Kirk.

At least 19 recordsLinked to original sources
PubMed2006

Motorcycling freedom: a paraplegics dream.

People with disabilities have the same rights as other members of society in directing and implementing the decisions which affect their lives, although it is not always afforded them due to physical limitations. A chance encounter by the author, a University of Western Australia mechanical engineering student, with a paraplegic man who expressed his dream of being able to ride a motorcycle again led to the design and build of a specially modified motorcycle that could be ridden safely and comfortably by a person without the use of their legs. The prototype involved several modifications which allow it to be ridden by a paraplegic person. They included, a thumb controlled pneumatic gear shifter, an integrated front and rear brake actuated with a single hand lever, ergonomic supports to hold the riders legs in place and an automatic stabilising system to balance the motorcycle at low speeds. The benefits that result from the inclusion of people with disabilities into regular leisure activities include normalisation as well as a sense of independence and freedom for the individual. It also allowed one man the chance to reach for his dreams.

Equipment Design↗
PubMed1999

Collisionally processed rocks on mars

The Pathfinder landing site on Mars has boulders that may be cratered (Stimpy), split (Chimp), fragmented (Book End and Flat Top), or otherwise partly destroyed (Yogi and Frog) by collisional processes. Atmospheric-entry calculations show that centimeter-sized projectiles survive passage through the martian atmosphere and encounter the surface of Mars at velocities of a few kilometers per second. Craters less than 1 meter in diameter may contribute to the evolution of the martian surface and its soils.

Journal Article↗
PubMed1991

Disruption of a coronary stent during atherectomy for restenosis.

Directional coronary atherectomy is being used in the treatment of atherosclerotic lesions in coronary vessels and vein grafts. This report describes the use of atherectomy for the treatment of restenosis of a coronary stent. The procedure was complicated by disruption of the stent which was snared by the atherectomy cutter.

Aged↗
PubMed1987

Bone marrow hypoplasia during intensive care: bone marrow culture studies implicating ranitidine in the suppression of haemopoiesis.

Two seriously ill patients with renal failure developed bone marrow hypoplasia and peripheral blood cytopenias during admission to an Intensive Care Unit (ICU). Both patients were being treated with ranitidine and, in both, there was evidence of drug accumulation. Serum from the patient with the highest concentration of ranitidine inhibited granulocyte-macrophage colony growth from normal bone marrow. The addition of ranitidine to cultures of normal bone marrow also produced a concentration-dependent inhibition of colony growth. Ranitidine should be used with caution in patients with renal failure where drug accumulation may seriously impair bone marrow function.

Aged↗
PubMed1985

Six-member stimulus classes generated by conditional-discrimination procedures.

In conditional-discrimination procedures with three sets of stimuli, A, B, and C, three stimuli per set (A1A2A3, B1B2B3, and C1C2C3), subjects (children and adults) learned to select Set-B and Set-C comparisons conditionally upon Set-A samples (A1B1, A1C1, A2B2, A2C2, A3B3, A3C3). If the conditional-discrimination procedures also generated equivalence relations, three 3-member stimulus classes would be demonstrable, A1B1C1, A2B2C2, and A3B3C3. In addition to these three sets, the present experiments used three other sets of stimuli--D, E, and F. The subjects learned to select Set-E and Set-F comparisons conditionally upon Set-D samples (D1E1, D1F1, D2E2, D2F2, D3E3, D3F3). This established a second group of three 3-member stimulus classes, D1E1F1, D2E2F2, and D3E3F3. In all, two groups of three 3-member classes were established by teaching subjects 12 conditional discriminations. The two groups of 3-member classes were then combined (successfully for 5 of 8 subjects) into a single group of three 6-member classes by teaching the subjects three more conditional relations (E1C1, E2C2, and E3C3). With three other children, enlarging the classes one member at a time also produced 6-member classes. As a consequence of class formation, 60 untrained conditional relations emerged from 15 that had been explicitly taught. Six of the subjects also proved capable of naming the stimuli consistently in accord with their class membership, but two subjects demonstrated class formation even in the absence of consistent naming.

Adult↗
PubMed1984

Gas exchange during ventilator treatment: a validation of a computerized technique and its comparison with the Douglas bag method.

In recent years a number of commercial instruments for on-line gas exchange measurements has been introduced. One of them, the Engström Metabolic Computer (EMC), is here clinically validated as compared to the standard Douglas bag method for gas sampling and a Centronic Mass Spectrometer (CMS) for gas analysis. VO2, VCO2 and RQ were simultaneously measured and calculated with both methods. Twenty individual gas exchange determinations were made at different times on 12 critically ill patients at the intensive care unit. There was a small but significant difference (P less than 0.025) of 4.3% +/- 8.4% (s.d.) between the two methods when they were used to measure VO2 (the EMC giving the lower value). The corresponding value of VCO2 was 2.4% +/- 9.1% (s.d.), and for RQ the difference was -1.98% +/- 7.1% (s.d.). These differences are not significant at the 95% level of significance. Determinations of oxygen uptake during ventilator treatment with standard methods usually involve technical difficulties and are associated with errors of method around 10%. Our results indicate a probable error of about 8.5% for VO2 in clinical situations. Considering the difficulties involved in determinations of gas exchange, the EMC method seems to be a valuable technique with an accuracy within acceptable limits.

Adult↗
PubMed1982

Comparison of respirable dust specifications with recent lung data.

This paper compares the two major respirable dusts size specifications with lung models derived from a recent review using computer simulation in logarithmic normal dust clouds. It was found that either specification gives reasonable reproductibility with respect to either the nose or mouth breathing lung models over the usual range of industrial dust clouds, and either could be chosen as a standard with only a slight adjustment in the corresponding dust control limit.

Air Pollutants, Occupational↗
PubMed1981

Evaluation of a prototype micro-electronic autoclave cycle integrator.

Instability and non-uniformity of spore preparations and the non-conformity of chemical indicators to the temperature coefficients of spore inactivation are problems associated with current methods of autoclave cycle monitoring. A prototype micro-electronic instrument, which largely overcomes these problems, is described. It monitors autoclave cycles in terms of the integral F0 and Nabla functions. Its thermometric and integrating accuracy is demonstrated. A discussion of the problems associated with the use of sensitive electronic instruments in the autoclave room environment reveals the need for independent monitoring areas when such devices are used. Inactivation constants were determined for spores of the organism Bacillus stearothermophilus, NCTC 10 003 and were described using D115 (12.0 min) and Z (9.0 degrees C) values and the first order reaction Arrhenius constants A 10(41.2) min-1) and Ea (74.4 kcal mol-1, 311 kJ mol-1). These have been compared with recently published values. The standardization of F0 and Nabla is discussed with reference to the setting of minimum values related to product bioburden and maximum values related to an acceptable degree of product degradation.

Electronics↗
PubMed1977

A canine model for reaginic hypersensitivity and allergic bronchoconstriction.

Immunization of neonatal dogs with a conjugate of 2,4-dinitrobenzene and ovalbumin (DNP2-OA), using aluminum hydroxide as the adjuvant, elicited long-lasting (over 30 wk) anti-DNP and anti-OA IgE antibody responses of high titers as determined by homologous passive cutaneous anaphylaxis. Low antigen doses of 10 or 50 mug were more effective than the higher doses of 250 or 1,250 mug in inducing high IgE antibody levels. However, this method of immunization failed to elicity any detectable IgE antibody response in adult dogs. Bronchoprovocation with antigen of sensitized animals having IgE antibody titers in excess of 64 resulted in a marked increase in airflow resistance, which could be corrected by the administration of nebulized isoproterenol. On the other hand, sensitized animals with IgE antibody titers in the order of 64 did not manifest significant bronchoconstriction on inhalation challenge but developed anaphylaxis following intravenous injection of the antigen.

Aging↗
PubMed1976

Blast crisis of chronic myeloid leukaemia (CML). I. Presentation simulating acute lymphoid leukaemia (ALL).

Seven patients presenting as an acute leukaemia caused difficulty in diagnosis. The lymphoid appearance of the balst cells either initially or during treatment suggested acute lymphoid leukaemia (ALL). In each case the Philadelphia chromosome was shown to be present thus suggesting that these cases were examples of chronic myeloid leukaemia (CML) presenting in blast crisis without a detectable chronic phase. The implications of these findings are discussed and the difficulty in achieving a precise diagnosis in the acute leukaemias is emphasised. Cytogenetic analysis should be carried out whenever the type of acute leukaemia present is of critical importance.

Adolescent↗