Vitamin A and bone growth : the reversibility of vitamin A-deficiency changes / by E. Mellanby.

  • Mellanby, Edward, Sir, 1884-1955.
Date:
[1947?]
Catalogue details

Licence: In copyright

Credit: Vitamin A and bone growth : the reversibility of vitamin A-deficiency changes / by E. Mellanby. Source: Wellcome Collection.

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    J. Physiol. (1947) io5) ^8^-399 . , 612.392.015 .. I VITAMIN A AND BONE GROWTH: THE REVERSIBILITY OF VITAMIN A-'DEFICIENCY CHANGES By E. MELLANBY From the Nutrition Building, National Institute for Medical Research, Mill Hill, London, N.W.l 0 (Received 1 July 1946) In a series of publications (Mellanby, 1926, 1931, 1933, 1934, 1935) it lias been shown that a deficiency of vitamin A in the diet of growing animals causes ; widespread nerve degeneration, both peripheral and central. Of the cranial i nerves, the olfactory, the optic, the trigeminal (first and second divisions) and I the auditory (both cochlear and vestibular divisions) are specially liable to ( suffer destructive changes. For the most part, under the conditions of these : experiments, the cranial motor nerves escape. In the spinal cord, afferent nerves having their origin in the posterior root ganglia are often destroyed, together with their neurones passing into the cord. In addition, some of the j endogenous ascending fibres are affected, especially the anterior and posterior cerebellar tracts. A cause of this widespread degeneration was suggested when the examination of serial sections of the labyrinth and its capsule revealed that vitamin A i deficiency results in a large bone hypertrophy which injures or destroys the nerve fibres and the cells of the spiral ganglion by pressing on the VIII nerve 5 (Mellanby, 1938). Other observations made it clear that in vitamin A- deficient animals the whole of the nervous system was under greatly increased pressure (Mellanby, 1939 a); the brain and spinal cord Were closely packed into ] the cranium and spinal canal, and it soon became evident that, because of their t abnormal growth, the skull and vertebrae had lost their primary function of protecting the nervous system and had become destructive agents. Later (Mellanby, 19395, 1941, 1943) descriptions were given of the abnormal . bone growth near the spinal and cranial nerve cells, and in the Croonian Lecture > of the Royal Society in 1943 a more detailed analysis of the abnormal growth I in two positions, namely, the basi-occipital bone and the vertebral column, was . presented (Mellanby, 1944). It was shown that the bone dysplasia which | resulted from vitamin A deficiency and had such grave effects on the nervous i system could be largely, if not entirely, explained by altered osteoclastic and i osteoblastic activity. I