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Biomedical subjects

I Cavill

Publications and source records attributed to I Cavill.

At least 55 records · Page 3Linked to original sources

The measurement of the total volume of red cells in man: a non-radioactive approach using biotin.

Present methods for measuring red cell volume are based on the dilution of radioactively labelled cells. This precludes the investigation in neonates and pregnant women. We present a simple method for labelling red cells with biotin. These cells may be injected intravenously and subsequently detected using streptavidin-FITC and flow-cytometry. A comparison of the red cell volume estimated using both 51Cr and biotin labelled cells in 19 patients showed no consistent clinically significant difference between the two. This novel label appears to allow red volume to be reliably estimated without using radioactivity.

Bacterial Proteins↗

Haemoglobinopathy screening in a 'low-risk' area of the United Kingdom: South Glamorgan, Wales.

Figures collected over 2 1/2 years of screening of women attending the antenatal clinics of South Glamorgan, Wales, showed that the percentage of women identified as a risk for haemoglobinopathy trait (7.4%) was almost twice that estimated from the 1981 Census data (4.1%) and that the incidence of a thalassaemia trait in these women (0.38% beta; 0.68% alpha) was similar to that of an area of supposedly greater risk in London (0.46% beta; 0.42% alpha). Figures from one laboratory showed that without a scrutiny of all antenatal clinic blood counts for thalassaemic indices some thalassaemia traits will be missed. The apparent incidence of the HbS trait was 0.13%, and reasons for this being an underestimate are given.

Female↗

Erythropoiesis in pregnancy.

The reticulocyte count, serum ferritin and serum erythropoietin concentrations were measured during the course of pregnancy in 41 women. A decrease in iron stores early in pregnancy was accompanied by a significant rise in the reticulocyte count until the 28th week. Erythropoietin levels did not rise significantly until the 28th week of pregnancy and had fallen to the post-natal level by 40 weeks. The results are consistent with an increase in erythropoietic activity early in pregnancy which did not appear to depend upon increased plasma erythropoietin levels.

Adult↗

Erythropoiesis in the anaemia of chronic renal failure: the response to CAPD.

Fifteen patients with chronic renal failure commencing CAPD treatment were studied by a sensitive ferrokinetic technique. All were severely anaemic with a low red cell volume (RCV). Plasma volume (PV) was raised in twelve. Mean red cell lifespan (MRCL) was reduced in eleven subjects, and marrow iron turnover (MIT) was inappropriately low but this was not related to erythropoietin levels. Six patients were restudied after several months CAPD. PV fell in four and RCV increased in all six. MRCL rose to normal in three. The other three subjects has an increase in MIT. Erythropoietin levels did not change significantly. The major cause of uraemic anaemia is a failure of erythropoiesis to match fully the demands of red cell destruction.

Adult↗

Quantitation of reticuloendothelial iron kinetics in humans.

Reticuloendothelial iron kinetics were investigated in a simultaneous dual-isotope study in 10 healthy adult subjects in whom 55Fe-ferric hydroxide phosphate colloid was used to label the reticuloendothelial iron pools, and 59Fe-transferrin was used to define plasma iron kinetics. The simultaneous clearance of 55Fe and 59Fe from plasma and the uptake of each into red blood cells were measured over 14 days. The 55Fe-colloid was cleared almost immediately, and its iron was rapidly released to bind to plasma transferrin. Red cell incorporation of 55Fe was, however, much slower than that of 59Fe bound to transferrin in vitro. The data were analyzed by a new model of reticuloendothelial iron metabolism that contained two reticuloendothelial iron pools; one had a rapid turnover and donated iron to transferrin, and the other, a storage pool, had a slower turnover. The transit pool contained a mean of 164 mumol iron with little variation between subjects, whereas the storage pool was somewhat larger (mean 873 mumol iron) and showed more marked variation between subjects. In general an equal proportion of the iron leaving the transit pool went to transferrin and to the storage pool. The distribution between the two routes did not appear to be related either to plasma iron concentration, latent iron-binding capacity, or transferrin saturation.

Adult↗

Assessment of cellularity in bone marrow fragments.

Bone marrow cellularity was measured using the Quantimet 720 Image Analyser in 50 biopsy samples. In haematologically normal subjects the percentage cellularity of the marrow was between 40 and 63%. Subjective assessment of cellularity was an unreliable indicator of the quantitative measure.

Biopsy↗

Anaemia in patients with myelomatosis.

Twenty-four untreated patients with myelomatosis were studied in order to characterize their anaemia, using standard haematological and ferrokinetic techniques, together with measurements of circulating erythropoietin, erythropoietin sensitivity of marrow cultures and in vitro measurements of haem synthesis. There is a reduction in total erythroid output by the marrow, together with a minor degree of plasma expansion. In patients with normal renal function there is an appropriate increase in erythropoietin in response to anaemia, but in a few cases there may be reduced response of CFU-E to the hormone in vitro. No abnormality of iron status or haem synthesis was found. One case of folate deficiency was discovered.

Adult↗

Erythropoiesis in the anaemia of rheumatoid arthritis.

Erythropoietic activity and mean red-cell lifespan were measured using 59Fe-transferrin in 32 anaemic patients with active rheumatoid arthritis (RA) and in 20 haematologically normal subjects. Marrow iron turnover (MIT) in the patients was normal and in only 11 was red-cell lifespan less than 70 d. Ineffective iron turnover (IIT) was significantly increased in those patients in whom there was evidence of iron deficiency (serum ferritin less than 12 microgram/l) but in the remaining patients IIT was significantly less than in the normal subjects. In a further 19 patients with simple iron deficiency anaemia IIT was significantly increased. The marrow response to chronic inflammatory disease is clearly distinct from that seen in simple iron deficiency and this suggests different pathogenic mechanisms for these two anaemias.

Adult↗

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↗