Biomedical subjects
Publications and source records attributed to B Kirk.
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.
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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.
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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.
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.
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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.
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.
Fourteen cases of philadelphia chromosome (Ph1) positive chronic myeloid leukaemia in blast transformation have been investigated using cell surface markers. Morphologically eight cases were lymphoid and the remainder myeloid in appearance. All cases were negative with surface markers for thymocytes and T and B lymphocytes. Five of the lymphoid cases reacted with an antiserum specific for acute lymphoid leukaemia )ALL) of non-T non-B type and were also weakly reactive with a lymphocyte reactive antiserum. A sixth patient, whose blast cells were anti-ALL negative (ALL-) at presentation, subsequently developed central nervous system leukaemia with anti-ALL positive (ALL+) blast cells in the CSF. In all cases the leukaemic blast cells showed greatly diminished expression of cholera toxin receptors when compared to granulocytic cells from the chronic phase of CML. This parallels weak or negligible expression of the cholera toxin receptor in ALL and AML. These results suggest that the blastic phase of CML may involve different cellular derivatives of a pluripotential stem cell in which the primary malignant/genetic changes reside. The blast crisis of CML can therefore be heterogeneous with respect to cellular expression and in a significant proportion of patients involves a cell which is by membrane markers and morphological criteria indistinguishable from that seen in the common form of ALL. In these cases the Philadelphia chromosome may be the only distinguishing cellular characteristic.
24 patients with Philadelphia chromosome positive chronic myeloid leukaemia (CML) in blast crisis were treated with intensive chemotherapy. 16 patients showed either partial or complete response to this treatment, but median survival remained short (13 weeks), and much of this time was spent in hospital. These results were not significantly better than those obtained by others using vincristine and prednisolone alone, and this combination of drugs can often be given on an outpatient basis. It is concluded that until more effective intensive therapy becomes available patients in CML blast crisis should be managed in such a way that the quality of life is not impaired; and that at present vincristine and prednisolone appears to be the most impaired; and that at present vincristine and prednisolone appears to be the most appropriate initial treatment, though even this is far from satisfactory.
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