Paul György

Experimental Production of Dietary Liver Injury (Necrosis, Cirrhosis) in Rats.

Liver injury, mainly in the form of acute diffuse necrosis combined with fat infiltration, has occurred irregularly in young rats fed a diet devoid of vitamin B (casein 18%, sucrose 68, melted butter fat 8, cod liver oil 2, salt mixture 4) and supplemented with thiamine, riboflavin and pyridoxine. 1 In some of these livers there was diffuse periportal fibrosis. Rats fed the same basal diet plus yeast, or concentrated yeast extract, were free from any pathological changes in the liver. Later, the occurrence of cirrhosis of the liver on a nutritional basis and its prevention similarly by the addition of yeast to the diet were reported in rabbits 2 and in guinea pigs. 3 The unpredictable and irregular incidence of liver injury in rats has been indirectly regarded as a basis for the assumption that the proper experimental conditions for the regular production of liver injury have not been provided by the experimental technic used. In view of the well known lipotropic activity of casein, 4 the high proportion (18%) of casein in the basal diet was considered to be possibly one important factor which might counteract other conditions that would be conducive to liver injury. Consequently, rats weighing between 100 and 250 g were put on a diet that had the following composition: casein 10%, sucrose 64, lard 20, cod liver oil 2 and salt mixture 4. This modified basal diet was supplemented with thiamine, riboflavin, pyridoxine and pantothenic acid. In this group of rats the incidence of liver injury rose from an irregular occurrence, as it was in the rats on the original diet (with casein 18% and butter instead of lard), to a regular complication. Necrosis with or without cirrhosis and cirrhosis without necrosis were observed in rats that died between the 100th and 150th experimental days or were killed on the 150th day.

Necrosis, Cirrhosis and Cancer of Liver in Rats Fed a Diet Containing Dimethylaminoazobenzene.∗

It was recently reported 1 that dietary liver injury (necrosis, cirrhosis) seen in rats fed a synthetic ration is determined in great part by the absence of the lipotropic activity of casein. These changes can be prevented to a large extent by the addition of casein to the diet, but this is accomplished more effectively by the combined oral administration of cystine and choline. During the last 2 years similar investigations have been carried out with the purpose of elucidating the cause of cirrhosis and cancer of the liver in rats brought about by the addition of butter yellow (dimethylaminoazobenzene, dissolved in oil) to a diet consisting of rice and carrots, as first described by Kinosita. 2 The question arose whether or not the same mechanism that proved effective in the prevention of simple dietary liver injury 1 may also play a rôle in the prevention of changes in the liver which follow the administration of butter yellow.‡ Results. 1. In a control group of rats fed basal diet A, consisting of rice, carrots, and dimethylaminoazobenzene in oil (0.6 g per kilo of diet), supplemented with 20 μg daily each of thiamine, riboflavin and pyridoxine and with 100 μg daily of pantothenic acid, cirrhosis, atypical, nodular proliferation of bile ducts and carcinoma§ of the liver were a regular feature. In different groups the incidence of these changes fluctuated from 80 to 100%. However, only 40% of rats fed the same diet with the addition of 18% casein∥ showed similar changes. These observations are in close agreement with the results obtained by Kensler and his collaborators 4 just published. 2. Sixty rats were put on basal diet A (rice, carrots, dimethylaminoazobenzene) with the usual supplements of thiamine, riboflavin, pyridoxine and pantothenic acid. In addition sub-group 1 (16 rats) of this experiment received from 10 to 20 mg of choline daily, sub-group 2 (12 rats) received from 25 to 50 mg of cystine daily and sub-group 3 (12 rats) received daily from 25 to 50 mg of cystine plus from 10 to 20 mg of choline. Sub-group 4 (20 rats) received no supplement. The results are summarized in Table I.

Effect of Dietary Hepatic Injury on Inactivation of Estrone

Summary Liver damage produced in rats by diets low in protein and high in fat was consistently reflected in the living animal by impairment in ability to inactivate estrone. The curative effect of large doses of yeast could be demonstrated. Vitamin B-complex deficiency was usually accompanied by a similar but less constant hepatic impairment and without anatomical damage to the liver. There appeared to be a strain difference in susceptibility. A mixture of known vitamins was only partially effective in abolishing the effect of the diet, while yeast was distinctly and more consistently effective.

Nutritional Dermatoses in Rats

Hitherto all scaly dermatoses produced in rats by means of diets have been broadly characterized as pellagra or pellagra-like. Failure properly and exactly to describe the scaly diseases of the rat and to differentiate one disease from another has led to confusion and controversy in the field of nutritional investigation. At least 3 scaly dermatoses can be produced in the rat and prevented or cured by nutritional means. They are due to (1) vitamin H deficiency (egg-white injury), (2) vitamin B6 deficiency, and (3) lactoflavin deficiency. (1) Vitamin H 1 deficiency disease is the name given to the general disorder experimentally produced in the rat by inclusion of a high proportion (15 to 40%) of egg-white in an otherwise well-balanced diet which contains all the well-known vitamins. Administration of vitamin H cures this condition. Rats kept on a diet of this kind exhibit in from 4 to 6 weeks typical symptoms of sebor-rheid 2 dermatitis, such as erythema, intertrigo particularly around the neck and genitalia, a brown crusting chiefly over the back that is similar to “cradle cap,” and scaling that progresses from the areas of intertrigo to involve the entire surface of the body and that leads finally to a generalized exfoliative dermatitis. Generalized alopecia and exquisite pruritus are also manifest. The hind legs and the ears escape involvement. Excoriations heal slowly. Skin abscesses are rare; when present they are ecthyma-like. Mild sublingual ulcers are fairly common. The microscopic picture reveals that in the earliest stages of the disease there is edema in the upper portion of the corium; there is also acanthosis with intercellular and intracellular edema. Altération cavitaire and spongiosis of the stratum spinosum precede the formation of intra-epithelial vesicles.

Distribution of Biotin and Avidin in Hen's Egg

Conclusions 1. Whole egg contains an excess of avidin, as the amount of biotin in the whole yolk is unable to neutralize the amount of avidin in the white of the same egg. 2. Biotin in egg yolk is present in a high molecular, undialyzable form which is physiologically active in yeast growth tests or in tests made on rats with egg-white injury.

Further experiments on nutritional achromotrichia in rats and mice.

From the results of previous experiments it has been concluded that “concentrates of pantothenic acid, with a purification up to 40 to 50%, appear to contain one factor but not the only factor concerned in the cure of nutritional achromotrichia in rats.” 1 Later, it became evident that this factor, which proved to be heat labile in alkaline solution, is identical with pantothenic acid. 2 In a group of rats kept on a diet free from pantothenic acid, administration of daily doses of from 75 to 100 μg of synthetic pantothenic acidf brought about cure of the nutritional achromotrichia in from 5 to 7 weeks. 2 In some rats the cure was slower and in a few it was never quite complete. These experiments were repeated with black mice‡ kept under similar nutritional conditions. The diet used was particularly conducive 3 to the production of acrodynia in rats. It consisted of 18 parts of purified casein,§ 10 of dried heated egg white, 58 of sucrose, 8 of melted butter fat, 2 of cod liver oil and 4 of salt mixture. Raw egg white was heated over a steam bath for 3 hours in order to destroy the injurious effect (“egg white injury” 4 ) it has on animals. The diet fed both to the rats and the mice was supplemented with 20 μg each of thiamin chloride, pyridoxine and riboflavin. In from 3 to 5 weeks, apart from the skin lesions, the fur of the mice became gray or brownish, similar in color to the fur of wild house mice or more silvery. Daily doses of from 50 to 100 μg of calcium pantothenate (synthetic, Merck) produced quick and definite effect on the depigmentation of the fur, with practical cure in from 3 to 5 weeks. The therapeutic effect on the cutaneous manifestations was even more rapid. 5 These lesions were similar to those described in rats as Type II 6 and to those recently observed in mice under similar conditions by Norris and Hauschildt. 7

Effect of Biotin Deficiency on Duration of Infection with Trypanosoma lewisi in the Rat.

Summary Biotin deficiency has been found to prolong the infection with T. lewisi in the rat. This effect can be negated by the administration of biotin to the deficient rat during the course of infection. Biotin appears to be instrumental directly or indirectly in the activation of the immune bodies in this infection.

Pediculosis in Rats Kept on a Riboflavin-Deficient Diet

Summary Chronic riboflavin deficiency in rats is often accompanied by pediculosis. This disease has never been observed in rats manifesting symptoms of a deficiency of other factors of the vitamin B2 complex. Administration of riboflavin by mouth has a curative effect on this type of pediculosis in rats.

The liberation of biotin from the avidin-biotin complex (AB).

Summary 1. Under the experimental conditions used biotin could not be liberated from combination with avidin by the proteolytic enzymes—pepsin, trypsin, pancreatin, and papain—nor by incubation with liver, kidney, muscle, or blood. 2. Biotin could be liberated from the avidin-biotin complex by oxidation with 0.45% H2O2. Amounts of yeast active material equivalent to 10 to 20% of the biotin originally bound were found.

Experiments on the Antidermatitis Component of the Filtrate Factor in Rats

Summary A purified but still crude zinc salt of pantothenic acid proved to be active in the cure of specific skin lesions and in promotion of growth in rats fed a diet devoid of the filtrate fraction. Autoclaving at pH 10 destroyed the activity of the preparation.‡