Carotene and vitamin A : the anti-infective action of carotene / H.N. Green and E. Mellanby.

  • Green, H. N. (Harry Norman)
Date:
[1930?]
Catalogue details

Licence: In copyright

Credit: Carotene and vitamin A : the anti-infective action of carotene / H.N. Green and E. Mellanby. Source: Wellcome Collection.

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    of growth and improvement in health could be effected. Thus in Experiment I the test consisted essentially of determining the prophylactic, and in Experiment III the curative action of carotene. DISCUSSION OF RESULTS. It is obvious from the above results that carotene acts as a very potent anti-infective agent. From Tables I-IV it will be seen that the response to carotene is as reasonably quantitative as could be expected. Complete protection against infection was always found when greater amounts than O’04 mgm. of carotene were given daily, even when a prolonged depletion period on a — vitamin A diet had preceded the addition of the carotene. Many of these animals must have developed an infection in the depletion period (on the basis of previous results) and yet complete recovery and good health followed. In the case of one animal in Experiment III receiving 0’04 mgm. of carotene no recovery followed and the animal died on the I07th day. This is an exceptional result, for even when only 0’02 mgm. of carotene was given to 3 animals in the same experiment they remained healthy and continued to grow throughout the feeding period. In the case of the animals receiving only O’Ol mgm. of carotene the protection against infection was less certain, and some died with organs invaded by micro-organisms. With 0’005 mgm. of carotene the protection afforded was still less, although even in this case, when the animals are compared with the controls receiving no carotene, there is evidence of an increased resistance. It is difficult to state the exact protective dose of carotene in the case of the rat, but probably in the average animal when no running-out period {i. e. deprival of vitamin A) is allowed, a daily dose of 0’02 mgm. is sufficient. After the animal’s body has been completely deprived of vitamin A and infective foci have probably started prior to the addition of carotene, a dose of 0’02 mgm. seems to be enough to restore perfect health and Table I.—The Cojnparative Effects of Varying Quantities of Carotene on Resistance to Infection. Exp. I: No Preliminary Depletion Period. Duration of experiment, 119 days. Nature of Survival Site and intensity of Growth response Remarks. supplement. time. • infection. (in gm.). O'Ol mgm. To end of . M.E. . 35-122 General condition good, carotene Ditto experiment Ditto . M.E.; mastoid . 34-140-131 . 5? . M.E. . 40-130 9? 9? ? 5 0‘005 mgm. * ? ? • ?) . T.A. + -f- . 35-119-97 . Scanty abdominal fat. carotene Ditto • V T.A.-b-t- . 39-124-111 . 95 99 5 J 106 . X.+ ; T.A.-h; M.E.-f; . 36-96-76 No Nil 50 bladder stone . T.A. -f -f 4- ; enteritis ; . 47-119-106 . ... • 5 39 uterus (cornu); X.+ . X.-b; T.A. + + A; . 42-129-121 . • ? ? 59 N.S.; bladder; kid- ney . T.A.-b-b-b ; M.E.-f + . 39-101-84 . T.A. - ' longue abscess. X. Xerophthalmia. N.S. = Nasal sinus. M.E. = Middle ear.