Studies in thiamine deficiency in man and experimental animals

This thesis deals with biochemical manifestations of thiamine deficiency in man and in dogs, and with the problems of detecting sub-clinical thiamine deficiency and of assessing the extent of clinical deficiency by biochemical means. The first section is a resume of the literature pertaining to the chemical estimations involved in the detection of thiamine deficiency viz, pyruvic acid and thiamine. The various tests of thiamine deficiency, involving these two estimations as used by the different workers in this field have been discussed. The chemical estimations of pyruvic acid and thiamine have been studied in detail and certain modifications have been introduced. A measure of the fasting and. resting blood, pyruvate concentration, and of the urinary excretion of thiamine in the 4 hours following a 1 mg, intravenous dose - the most widely used teat a of thiamine deficiency- have been employed in the investigation of thiamine nutrition in poet-gastrectomy patients, A comparison of the thiamine status of 17 post-gastrectomy patients and 24 normal subjects has been made. An outbreak of thiamine deficiency in greyhounds led to a controlled study of this condition in dogs. The deficiency was due to the destruction of thiamine in the preparation of the food prior to its being fed to the dogs. This diet was shown by chemical analysis to have a very low thiamine content. The course of thiamine depletion and the subsequent states of sub-clinical and clinical thiamine deficiency were studied biochemically. Blood pyruvate concentrations in the fasting and resting state, and following mild exercise, were followed throughout the duration of the experiment. Blood pyruvate concentrations have also been studied at Intervals during exercise. The effect of the ingestion of glucose on the blood pyruvate concentration has been studied. Once before, and three times during the course of the experiment urinary thiamine excretions were estimated following an intravenous test dose. The results of feeding this same thiamine deficient diet was also studied using collies and terriers as experimental animals. The stability of thiamine at various pH values was next investigated; the effect of heat was also studied. Thiamine deficiency in post-gastrectomy patients was discussed in relation to the stability of thiamine at the pH of the gastro-intestinal tract. Thiamine deficiency in the greyhounds was discussed in relation to the stability of thiamine under the conditions of the preparation of food. Finally the various methods of detecting thiamine deficiency have been critically reviewed in the light of the work recorded in this thesis.