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Biomedical subjects

C Ricketts

Publications and source records attributed to C Ricketts.

At least 19 recordsLinked to original sources
PubMed1992

Benefits and weaknesses of a cardiac rehabilitation programme.

The British Heart Foundation and the Chest, Heart and Stroke Association have allocated funds to develop cardiac rehabilitation programmes. We have recently completed and now evaluate an exercise-based rehabilitation course reinforced with advice about return to normal activity for 110 patients who had suffered acute myocardial infarction. Patients admitted to the Plymouth cardiac care unit were randomised into groups: a control group to receive standard hospital care, and a rehabilitation group who, in addition, received an exercise programme reinforced with advice. Patients were assessed at entry to the study and at intervals thereafter. Assessment was by questionnaire and objective tests consisting of a 12-minute walking test and weekly outpatient pedometry. In the rehabilitation group patients were able to walk further and faster, return to work earlier, undertake more housework, and resume normal sexual activity; they were less short of breath and did not experience more angina. However, the rehabilitation course brought little benefit to the patients' perception of well-being and their anxiety about health or their outlook on life. Exercise and advice are important components of a rehabilitation programme, but more attention needs to be given to the psychological aspects of recovery from a heart attack.

Adult↗
PubMed1979

Erythropoiesis and iron metabolism in Hodgkin's disease.

Recently developed techniques for the investigation of iron kinetics were used to study the disturbance of iron metabolism in 19 untreated patients with Hodgkin's diseases (HD). The erythroid abnormality in newly diagnosed HD appears to be confined to those patients with systemic symptoms of weight loss, night sweats and fever, and consists of depression of marrow erythroid activity. These patients had a significnatly lower haemoglobin and serum iron concentration and a higher serum ferritin concentration, both when compared to normal subjects and to those patients with HD who lacked systemic symptoms. Ineffective erythropoiesis and red-cell destruction were not significantly increased. The present findings, confirm that HD patients with systemic symptoms have a depression of erythropoiesis, and that in these patients the marrow fails to respond to the stimulus of mild anaemia.

Adolescent↗
PubMed1979

Erythropoiesis, iron stores and tissue iron exchange in man.

1. The exchange of iron between plasma and erythroid and non-erythroid tissues was measured in 14 normal subjects, 17 iron-deficient patients, nine patients with primary idiopathic haemochromatosis and in 13 patients with haemolytic disorders. 2. The two main factors determining tissue iron turnover were shown to be the level of iron stores and the erythropoietic activity of the bone marrow.

Adult↗
PubMed1979

An evaluation of two methods of laboratory quality control.

Two methods for quality control of automated blood counters have been compared: (1) monitoring results from patients' samples, and (2) analysis of results of a stable whole-blood control. The latter method proved better able to distinguish calibration changes from patient variation.

Erythrocyte Indices↗
PubMed1979

Measurement of haemolysis in patients with prosthetic heart valves.

Haemolysis following prosthetic heart valve insertion can be precisely and sensitively measured by means of a 59Fe ferrokinetic technique. Results obtained in a small series of patients with either Starr-Edwards or Brunwald-Cutter valve replacement are presented.

Aortic Valve↗
PubMed1979

Studies in desferrioxamine and ferrioxamine metabolism in normal and iron-loaded subjects.

Plasma concentrations of desferrioxamine and ferrioxamine were measured following bolus injections of desferrioxamine and during 24 h infusions of the drug. [59Fe]ferrioxamine clearance and urinary iron excretion were also measured. Higher plasma ferrioxamine concentrations were found in iron loaded subjects and higher desferrioxamine concentrations in subjects with normal ironloads. There is a correlation between the circulating concentration of ferrioxamine during an infusion and the 48 h urinary iron excretion. The data suggests that the amount of iron chelated in vivo is related to an increase in the size of an intermediate chelatable pool rather than the total amount of the iron load. The well-recognized delay in urinary iron excretion appears to be related to active tubular reabsorption of ferrioxamine.

Blood Transfusion↗
PubMed1979

A method for the investigation of reticuloendothelial iron kinetics in man.

A colloidal suspension of hydrolysed radio-iron of high specific activity has been developed for the investigation of reticuloendothelial (RE) iron kinetics in man. Following intravenous injection this material is cleared rapidly by the RE system and the iron released intn to the endogenous RE iron load, and it has proved possible to measure RE iron release without disturbing the normal iron flow.

Anemia, Hypochromic↗
PubMed1979

Variability of serum ferritin concentration in normal subjects.

Serum ferritin concentrations were measured in normal subjects over periods of 1 day, 1 week and 7 weeks. The variation of the results was compared with variation of control of control sera. In most of the subjects the variation in the results could be attributed to the variation in the method of measurement. No diurnal variation in serum ferritin concentration was observed.

Circadian Rhythm↗
PubMed1978

Ferrokinetics: methods and interpretation.

The measurement of erythroid activity is based on the study of plasma iron kinetics. The radioiron injected should be bound specifically to transferrin, and the measurement of plasma 59Fe activity should be corrected for variation in plasma iron concentration. In addition, 59Fe-transferrin activity should be measured free of 59Fe-haemoglobin contamination. Analysis of the plasma 59Fe clearance curve over 14 days can give measures of total, effective and ineffective erythropoiesis, together with the red cell lifespan. Simpler ferrokinetic studies cannot be reliably used to assess erythropoiesis.

Bone Marrow↗
PubMed1977

Ferrokinetics and erythropoiesis in man: red-cell production and destruction in normal and anaemic subjects.

Recent advances in the analysis of plasma 59Fe clearance have produced a unified method for measuring effective and ineffective erythropoiesis (Ricketts et al, 1975). We have used this method to investigate the balance between red-cell production and destruction in normal subjects and in patients with megaloblastic anaemia, iron deficiency anaemia, and refractory hypoplastic anaemia. The results show that the normal marrow can maintain an appropriate red-cell mass by altering red-cell production to match destruction. In the anaemias we have studied there is an increased rate of either intra- or extra-medullary red-cell destruction. The response of the marrow may be limited by iron supply, by defective nuclear maturation or by some intrinsic marrow defect.

Adult↗
PubMed1977

Ferrokinetics and erythropoiesis in man: an evaluation of ferrokinetic measurements.

The plasma iron clearance half-time and plasma iron turnover have usually been interpreted as measures of total erythroid activity and the red-cell utilization of 59Fe has been equated with effective red-cell production. Erythrocyte iron turnover has sometimes been calculated as the product of plasma iron turnover and percentage utilization. We have assessed these measurements as estimates of erythroid activity by comparing them with total marrow iron turnover and red-cell iron turnover determined by the method of Ricketts et al (1975) in 10 normal subjects and 51 patients with an uncomplicated haematological disorder. The results show that the plasma iron clearance half-time does not reflect erythroid activity and that plasma iron turnover can be particularly misleading in patients with reduced marrow activity. Red-cell utilization and erythrocyte iron turnover give a distorted reflection of effective erythropoiesis except in patients with erythroid hypoplasia. Marrow iron turnover and red-cell iron turnover provide more realistic and generally applicable assessments of the degree and effectiveness of erythroid activity.

Bone Marrow↗
PubMed1977

The measurement of red cell lifespan using 59Fe.

Red cell lifespan has been measured using 51Cr and 59Fe in 19 patients. 59Fe can be used to give results which agree closely with those obtained using 51Cr provided that the plasma 59Fe clearance curve is properly defined and the data analysed correctly. In some patients elution of 51Cr may be more than three times the normal level and the use of 59Fe may provide the only reliable estimate of red cell lifespan.

Chromium Radioisotopes↗
PubMed1977

Erythropoiesis in the anaemia of chronic disease.

The amount and effectiveness of erythropoiesis was measured using 59Fe in 10 patients with the anaemia of chronic disease and in 10 iron deficient patients with a comparable degree of anaemia. In both conditions the anaemia was the result of the failure of the marrow to compensate for a modest degree of peripheral haemolysis but ineffective erythropoiesis was significantly greater in iron deficiency than in chronic disease. The results suggest that although the peripheral blood picture is similar in both conditions the anaemia of chronic disease cannot be attributed simply to iron deficient erythropoiesis.

Anemia↗