Should relatives be allowed in the resuscitation room?
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Biomedical subjects
Publications and source records attributed to I Dukes.
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The effect of cytosolic free Mg2+ concentration on the regulation of myocardial function was studied by dialyzing isolated guinea pig ventricular myocytes with different internal Mg2+ concentrations [( Mg2+]i). We found that elevation of [Mg2+]i shortened the action potential and suppressed the Ca2+ current. Mean values recorded for action potential duration in cells dialyzed with solutions containing 0, 1.3, and 9.4 mM Mg2+ were 620 +/- 40, 400 +/- 25, and 60 +/- 10, respectively. The suppressive effect of [Mg2+]i on the action potential duration correlated significantly with the suppressive effects of [Mg2+]i on the Ca2+ current. In cells dialyzed with nominally zero Mg2+, calcium current was prominent (3.5 +/- 0.58 nA). At [Mg2+]i of 1.4 mM, calcium current was significantly smaller than in zero [Mg2+]i and was almost completely inhibited by dialysis of the cell with 9.4 mM Mg2+. The Mg2+-induced block of the Ca2+ current was due to steady-state inactivation of the high threshold calcium channel. The block was observed in the presence or absence of adenosine 3',5'-cylic monophosphate and was not reversed by elevation of external Ca2+ concentration, addition of adrenaline, or large negative potentials. These data suggest that cytosolic Mg2+ regulates Ca2+ channel activity by a novel mechanism, unrelated to its effect as a blocking particle of the open channel.
Transformation to an acute promyelocytic leukaemia occurred in a patient approximately 2 years after having been diagnosed as suffering from chronic myeloid leukaemia (CML). At this time, in addition to the Ph1 chromosomal aberration, an isochromosome 17q [i(17q)] was noted. The t(15:17) was absent. The implications of this are discussed.
The karyotype, leukemia cell morphology (FAB classification), ethnic group, age, sex, and survival were compared in 60 patients with acute nonlymphocytic leukemia (ANLL), to determine their diagnostic and prognostic significance. An ethnic age difference was observed; a significantly greater number of black patients were children. The majority of children were males. A higher frequency of chromosome abnormalities was detected in children, yet they survived longer than adults. A specific, significant association between a (8; 21) karyotype and M2-ANLL was confirmed; four of ten patients with M2-ANLL showed this translocation. The more mature morphology of M2-ANLL was associated with a longer survival irrespective of karyotype, ethnic group, and age. The specificity of t(15; 17) in M3-ANLL and nonrandom monosomy 7 in preleukemic children was confirmed. Patients, particularly adults, with normal karyotypes tended to survive longer than those with abnormal karyotypes. The patient's age and the differentiative capacity of the leukemic cell appear to be as important as the karyotype in determining survival. The nonrandom association of certain chromosome aberrations in ANLL appears to be worldwide.
Gait was analyzed in seven otherwise healthy males at least 11 mo after they had recovered from a traumatic unilateral transmetatarsal amputation incurred during the course of their usual occupation. All seven were fitted with a semirigid foot orthosis. Four were also fitted with a Chopart prosthesis. Gait was evaluated with forceplate measurements of ground reaction force during free walking, by clinical observation of such ambulation on videotape, and by the subjective impression of the men as obtained by a questionnaire. In all men, with unmodified footwear, with the orthosis, and with the prosthesis, the forceplate data showed an abnormal pattern characterized by reduced stance duration and deficient forward propulsion on the amputated side. The abnormality and asymmetry of ground-reaction forces were less with greater preserved stump length and for a given stump length were with the above-ankle concept (Chopart) prosthesis than with the below-ankle concept. These features were recognized during the clinical analysis of all footwear, but there was an extra irregularity of weight progression noted with the fixed ankle of the Chopart prosthesis. The questionnaire reported stump problems to be the principal difficulty, and the follow-up revealed persistent attempts at surgical management including consideration of amputation at a higher level. It was concluded that the patient and the surgeons are likely to choose preservation of limb length over considerations of function during acute care and that the prosthetic concept best suited to deal with the resulting stump should emphasize unloading the distal part of the stump and smoothing out the impulsive force peak on the stump in late stance to minimize pain and to enhance ambulation capacity.