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dc.contributor.authorGordon, Neil S.en
dc.date.accessioned2018-09-13T15:57:51Z
dc.date.available2018-09-13T15:57:51Z
dc.date.issued1943
dc.identifier.urihttp://hdl.handle.net/1842/32328
dc.description.abstracten
dc.description.abstractThe experimental and theoretical data on the actions and uses of Vitamin E. is so conflicting, and in many cases so indefinite, that little more can be done than to point out what has been the most valuable of the experimental work and what are the most likely of the theories brought forward to explain the possible effect of its lack. Points that have already been discussed will only be referred to pi/in this section with An indication as to where this has been done.en
dc.description.abstractA short history of the vitamin is given to start with. Then the chemical isolation of the vitamin is traced from when a _n. a -'known factor influencing normal reproduction was first thought to be present in wheat germ oil till the vitamin was synthesised. Details of the chemical tests are given and it is noted that Emmerie and Engel's method is the best. The test may be applied to estimations of the Vitamin E. content of the blood serum. Methods of biological assay of the vitamin are discussed and the difficulties in performing this are noted. There does not seem to be a very close agreement between the two methods for estimating quantities of Vitamin E, but if it was proved both by chemical tests and biological assay that synthetic tocooherol and natural Vitamin E had similar effects on experimental animals, it would be possible to dispense with the latter test and use only the former. Little information on the action of Vitamin E is derived from the chemical studies except that it is unlikely to play a part in the oxidation -reduction processes of the cell, as when tocopherol is oxidised it gives rise to physiolosically inert substances.en
dc.description.abstractThe next section deals with certain physiological problems. It is noted that defects,in absorption in individual animals and human beings may explain why conditions stated to be due to deficiency of the Vitamin may arise only in certain cases while others remain normal on the same diet. These individual variations may also apply to the utilisation of the vitamin. Examples of diets used to produce Vitamin E. deficiency in experimental animals are given and the evidence for the occurrence of a natural deficiency of Vitamin E. in animal and human diets is reviewed. The occurrence of the vitamin in nature is so widespread that this seems unlikely although the question cannot be settled till the absolute quantity of the vitamin in various diets is estimated and till it is known what are the minimal requirements for the vitamin, if any, needed by various animals and by man.en
dc.description.abstractas these requirements are not known the dose of the vitamin needed to cure pathological st,etes due to deficiency of the vitamin can only be estimated by the effect that various doses have in curing these conditions. There is no doubt that lack of the vitamin caused disturbances of the reproductive and nervous systems of rats, but it is not so certain that similar conditions in human beings ere also caused by this deficiency. So in the present state of our knowledge the only way to estimate the curative dose in man, is to find the amount of the vitamin which cures a similar condition in the rat, and calculate it by means of relativ: wei hts. This is obviously unsatisfactory but till it is known whether the vitamin is needed by man at all, it would be better to have a standard scale of dosage so that the work of various investigators could be more easily compared. A list of the proprietary preparations used in clinical medicine is given and in most cages the amount of tocopherol that these contain is stated.en
dc.description.abstractThe fact that little storage of the vitamin occurs in the body is noted. The storage that does occur1takes place mainly in the subcutaneous and intraperitoneal fat. The means of supply of the vitamin from the mother to the young in experimental animals is described. It takes place almost entirely through the mammary gland and very little through the placenta. That the supply is small in amount is proved by the fact that it is insufficient in females to prevent resorption in the first gestation or to protect males from testicular damage for more than seventy to eighty days.en
dc.description.abstractExcess of the vitamin apparently produces no harmful effects but certain ceses of hypersensitivity to the vitamin are quoted. It is not quite certain if these were really due to the vitamin itself or to other impurities in the preparations used.en
dc.description.abstractFinally it is noted that excretion of the vitamin only occurs when the intake is high and that excretion in the faeces occurs at a lower intake than excretion in the urine.en
dc.description.abstractAfter these introductory sections a study is made of the results of a deficiency of the vitamin on the various systems of man and of animals. First the effect of. Vitamin E deficiency on cell metabolism is considered. It is thought that the vitamin may be needed for the normal function of the cell nucleus and that lack of it may result in an interference with cell division. It may act as a morphological hormone necessary for synthesis of the nuclear chromatin or for its physio- chemical structure. Certainly if this was so it would offer a common etiological cause for all the effects of Vitamin E deficiency, the occurrence of lesions in certain situations such as the nervous system, the developing embryo and the germinal layers of the testis, being an acute manifestation of the deficiency in cells which are rapidly dividing or have been previously damaged by some other noxious agent. Changes in the cytoplasm of these cells are almost certainly secondary to nuclear changes. Against this theory of restricted cell division is the occurrence of signs of uncontrolled cell proliferation which has been found to occur in developing chicks deprived of Vitamin E.en
dc.description.abstractIt is also suggested that Vitamin E plays a part in the oxidation -reduction processes of the cells, especially in those of the fats. There is little evidence for this as the oxidation processes and general metabolism of Vitamin E deficient animals d. e not lowered. It is possible that the Vitamin has an anti-oxigenic action, protecting the cells against harmful antoxidising fatty acids, although this is improbable also has its protecting power does not correspond to its Vitamin E activity in the various types of tocopherol.en
dc.description.abstractThe next section deals with the pathological conditions of cells deprived of Vitamin E. In chick embryos it is found that lack of Vitamin E results in some of the cells proliferating in an uncontrolled fashion. Actual lymphosareoma and reticular cell sarcoma were noted in some of the animals although it is doubtful if these were primarily clue to Vitamin E deficiency. The occurrence of fibroma of the uterus is apparently more frequent in Vitamin E. deficient rats and some Authors have found that Vitamin E. raised the threshold of resistance to the production of experimental tumours in these animals. Many other Authors have failed to confirm this latter finding. Other Experimenters produced tumours by administration of wheat germ oil, but this was almost certainly due to carcinogenic substances in the oil and not to Vitamin E. However the fact that Vitamin E. is supposed to stimulate the growth of cells and its deficiency to prevent cellular division, and that it is chemically related to human carcinogenic agents makes it more lusty that excess of the vitamin and not a lack should result in malignant changes. This question cannot be cleared up till further experiments are carried out and till it is known if Vitamin E has similar functions in different species of animals.en
dc.description.abstractIt was thought that lack of the vitamin might effect the haematological organs. A leukaemic litre condition and a haemolytic anaemia have been noted in chicks deprived of Vitamin E. but it has not been proved if this was the real cause of these conditions. The bulk of experimental evidence indicates that Vitamin E excess or deficiency has no effect on the blood picture or on iron metabolism. Vitamin E has no place in the therapy of blood diseases in clinical medicine. It has been tried in wounds and such conditions where cellular proliferation is taking place, but, although there have been some reports of its value in these conditions, they have been insufficient for any conclusions to be drawn from them.en
dc.description.abstractThen the effect of Vitamin E. defeciency on the female reproductive system Is no doubt that the vitamin is necessary for the normal completion of pregnancy in rats. If it is deficient the embryo dies and is absorbed. The pathological changes occurring in the embryo prior to and after death are described in detail. It is noted that the foetal placenta is primarily affected, showing such changes as atrophic allontoic projections, but the maternal placenta is apparently only involved secondarily to the foetal changes. Lesions in the embryos of Vitamin E. deficient chicks are also described as they differ from those described in the case of the rat.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2018 Block 20en
dc.relation.isreferencedbyen
dc.titleVitamin E: with special reference to its application in clinical medicine and the experimental evidence on which this is foundeden
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnameMD Doctor of Medicineen


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