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Title: Blood volume studies on domesticated animals
Author: Lauder, Ian M.
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1966
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Methods for determination of blood volume in man and common laboratory animals have been the subject of many investigations over the past twenty years, The availability of Isotopic markers for red blood cells and plasma proteins made such studies technically easier and more accurate. By comparison these methods and measurements have been applied relatively seldom to the domesticated animals. The aim of the work described in this thesis was to apply to the domestic animals blood volume techniques which had proved to be successful in man. Early on in this work it became clear that because of species differences modifications of existing methods would have to be made, e.g. it was found that the uptake [32]P by red cells showed very wide species differences. Perhaps the most important species anomaly was found in the measurement of "trapped plasma" in the haematoorit. This is a very important correction which has to be applied in all precise work, particularly where efforts are being made to measure true blood volume by simultaneous estimation of red cell volume and plasma. This species anomaly had not been formerly reported. A critical approach to the technicalities of measuring trapped plasma was made, and a method developed which overcomes many of the difficulties involved in the 'direct' procedure. Using this method a substantial number of determinations of trapped plasma were carried out on the bloods of normal horse, oow, shoep, pig and dog, under centrifugation conditions suitable for each species. While centrifuge condition were being investigated an important temperature effect on trapped pleasma observed. A study was also made of the distribution of trapped plasma in the red cell column, thus allowing variations in hematocrit to be taken into account in correcting for trapped plasma. In the estimation of trapped plasma in the foregoing experiments centrifugation was carried out in polythene tubes or Wintrobe hematocrit tubes at an RCF of 1500 g for varying periods of time. Chien, Dellenback, Ussmi and Gergesene (1965) compared trapped plasma in the hematocrit of various species when the blood was spun at 1500 g for 30 minutes in Wintrobe tubes and when spun at 15000 g for five minutes in micro-hematocrit capillary tubes. Though the latter method of centrifugation resulted in a much lower proportion of trapped plasma, a species difference was still quite obvious. Even after centrifugation at the higher impulse, the red cell columns of goat and sheep bloods were found to contain 9 per cent and 4 per cent trapped plasma respectively. Marked species differences were found in the uptake of [32]P by red blood corpusooles. Red cells of the ruminants, cow and sheep, and the cells of the horse labelled relatively slowly with this isotope. Some species differences of this nature had been noticed previously by Hansard et al (1953) and Sohambye (1952a) . It was found that removal of plasma from the cells before addition of the isosope increased the amount and rate of uptake of [32]P and in the larger species this was of marked practical value. In studying the persistence of [32]P-labelled cells in the circulation the radioactivity of samples was related to a common haematocrit, but although this was done with a correct allowance for trapped plasma the disappearance curves showed significant fluctuations. The rate of disappearance however was less than that described by Hansard et al (1953). When [51]Cr became available it was used for labelling red cells simulataneously with [32]P and the uptake and loss from the circulation of the tow isotopes was compared. It was found that the red cells of all the species studied took up [51]Cr rapidly and effectively. The loss of [51]Cr from the circulation was less rapid than that of [32]P but it was found that in the farm animals the rate of loss of [51]Cr was distinctly greater than the loss rate described in man and the dog. Blood volumes based in labelled cells in general were in agreement with the results reported in the literature of the last fifteen years. Blood volumes based on [51]Cr-labelled cells were smaller than those based on [32]P-labelled cells in all the species examined. As the red cells of species which labelled poorly with [32]P labelled rapidly and effectively with [51]Cr, and as the less of [51]Cr from the circulation was less, it was considered to be the label of choice for blood volume estimations based on labelled cells. It was considered that the results obtained by the use of labelled cells were not quite satisfactory and that the use of plasma protein labelled with [131]I might give better results and was worthy of further investigation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available