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Biomedical subjects

N Veall

Publications and source records attributed to N Veall.

At least 55 records · Page 3Linked to original sources
PubMed1976

The clinical measurement of skeletal blood flow.

1. A new method for measurement of skeletal blood flow is described which depends on the complete extraction of 18F in a single passage through bone. 2. Plasma concentration and urinary excretion are measured over a 2 h period. The technique of impulse analysis is used to determine the initial transfer rate of 18F to bone and extravascular extracellular fluid (ECF). The ECF component is evaluated by using a second tracer (51 Cr-EDTA or 82Br) and the bone transfer rate obtained by difference. The 51Cr-EDTA data also provide an estimate of glomerular filtration rate and enable a correction to be applied for urinary bladder retention when necessary. 3. Duplicate measurements of skeletal blood flow in eight normal male volunteers gave mean flows between 4-4 and 5-9% of blood volume/min, or about 4 ml min-1 100 g-1 of bone. The variation between normal subjects was least when the results were expressed as % of blood volume/min rather than ml/min, ml min-1 kg-1 or ml min-1 1-73 m-2 body surface area. The precision of the technique was estimated to be 16-4%. 4. Addition of 1-5% random noise to the input data resulted in an uncertainty of 8-5% in the measurement of skeletal blood flow, suggesting that improved precision depends on closer control of physiological variables. 5. In six patients with severe untreated Paget's disease of bone, skeletal blood flow was 8-4-15-3% of blood volume/min. The increase was significant in all cases. 6. The absorbed radiation dose is low, so that the measurement can be repeated.

Adult↗
PubMed1974

Effects of therapy on rate of absorption of calcium from gut in disorders of calcium homoeostasis.

A development of the double-tracer calcium absorption test, in which a function is derived for single-passage entry rate from the gut with time, has been assessed in various disorders of calcium homoeostasis. Single tests are diagnostically useful in calcium malabsorption but because of the wide spectrum of normal values a single test can only moderately enhance the accuracy of the diagnosis of hypercalcaemic states made primarily by other methods. On the other hand serial studies in the same subject can be much more informative because the test is normally highly reproducible if conditions are unchanged. Serial studies play an important part in assessing the efficacy of established methods of treatment in disorders of calcium homoeostasis and should be particularly helpful in studying the effects of new forms of therapy on the absorption process.

Adult↗