George R. Sharpless

A New Goiter-Producing Diet for the Rat

Summary In 4 to 8 weeks, a diet containing 75% raw soy flour induces in the thyroid of young rats an enlargement of 3 to 5 times normal. The enlargement is accompanied by hyperplasia and loss of colloid. Although the diet contains more iodine than would be expected, additional iodine will completely prevent the enlargement.

Limitation of Fluorine Toxicosis in the Rat with Aluminum Chloride.

Fluorine fed in low concentration has been shown to cause defective teeth in guinea pigs, rats, dogs, and cattle. In higher concentrations it causes inferior reproduction, poor bones and inferior growth or death. 1 Recently it has been shown that mottled enamel of human teeth is caused by the toxic action of fluorides present in drinking water. 2 This is a report of some work done in the search for a substance that would limit the toxic action of fluorine. Salts of lanthanum, cerium, thorium, and boron, which form insoluble or complex fluorides were found to give either no protection or, as in the case of lanthanum, only slight protection. Aluminum chloride was found to inhibit to a large extent the toxic effect of fluorine. The basal diet used was as follows: yellow corn meal 30.0 parts, ground whole wheat 30.0 parts, whole milk powder 30.0 parts, linseed meal 5.0 parts, alfalfa meal 3.0 parts, and wheat germ 1.0 part. Fluorine was added to this diet as a solution of sodium fluoride. Aluminum chloride was also added in solution. When both were added the solutions were combined. Sodium fluoride was fed in 2 concentrations, 0.025 and 0.1% of the diet. Aluminum chloride was fed in concentrations of 0.5% and 2.0%, which is equivalent to 0.056 and 0.224% aluminum respectively. Effect upon Growth. Sodium fluoride fed at a level of 0.025% of the diet had no effect on the rate of growth. Animals fed the diet containing 0.1% sodium fluoride grew at approximately two-thirds the normal rate. By adding 0.056% aluminum to the diet as the chloride, normal growth was obtained. Since it has been shown that calcium fluoride is less toxic to growth than sodium fluoride 3 the effect of calcium salts added in place of the aluminum was also studied.

Choline and epithelial hyperplasia in the forestomach of rats.

Summary Choline is necessary to help maintain normal squamous epithelium in the forestomach of rats fed white flour. This observation explains why protein tends to prevent and fat tends to increase hyperplasia of the forestomach epithelium.

Failure of Phenosulfazole (Darvisul) in Treating Experimental Viral Infections

Conclusion Phenosulfazole (Darvisul) showed no beneficial effect in the treatment of mice infected with the Columbia SK virus and other neurotropic viruses, including a rodent adapted strain of poliomyelitis (MEF-1 strain). The lack of therapeutic effectiveness of the drug was also observed in monkeys infected intranasally with the Brunhilde strain of poliomyelitis virus. In other viral and rickettsia1 infections of mice and of developing chick embryos treatment with pheno-sulfazole was of no therapeutic value, with the possible exception of psittacosis in which a slight inhibition of growth in the developing chick embryos was observed. However, even in the latter case the effectiveness of phenosulfazole therapy was of much lower magnitude than that observed with other sulfonamides,4-6 or antibiotics.7

Vitamin C Nutrition in Artificial Fever

Summary Studies of Vitamin C excretion before and after periods of artificial fever show that fever increases the Vitamin C requirement of man. Studies of Vitamin C stores in adrenals and kidneys of guinea pigs show that artificial fever increases the requirement or accelerates the destruction of Vitamin C. Since guinea pigs cannot lose Vitamin C in sweat, an increase in the physiological need for Vitamin C during fever is indicated.

Neoplastic hyperplasia of gastric mucosa in rats.

This is a report of the production and prevention of morphological changes in the fore-stomach of rats by means of the diet. Pappenheimer and Larimore 1 described lesions in the fore-stomachs of rats which appeared as round or oval discs with a small central ulcerated depression. The cause of the lesion was not found, but excess base or acid or Vitamin A deficiency were found not to be the etiological agents. Findlay 2 described changes in the fore-stomach associated with Vitamin B deficiency. Fujimaki has published a number of reports on the production of similar morphological changes in the fore-stomachs of rats by feeding different purified diets. His first hypothesis 3 , 4 was that the condition was caused by Vitamin A deficiency, but later 5 , 6 found that butterfat and/or cod liver oil caused a more marked change. The conclusion was drawn 6 that any of a number of fatty acids might play a partial etiological rôle. The basal diet used to produce the lesion described here is as follows: Casein (vitamin free) 4.0%; dried brewers yeast 5.0%; salts McCollum No. 185, 4.0%; butterfat, 5.0%; carbohydrate (starch, sugar, or dextrin), 82.0%; viosterol (15 drops per kilo of food). Rats 28 to 35 days old, weighing 60 to 110 gm. were used. The lesion develops within 3 months, and all of the animals on the above diet which have been examined to date (40) have been affected. The macroscopic appearance of the lesion varies from a few small elevated round or oval discs to long ridges of thickened epithelium with small papillomatous projections. There is a depression in the center of ridges and discs which may show ulceration. The normal fore-stomach is thin and elastic, but in animals with a severe lesion the epithelium is so greatly thickened that its elasticity has been lost. Older lesions may show from 2 to 8 epithelial cysts which vary in size up to 6 mm. in diameter. The most frequent site of occurrence is near the ridge separating the fore-stomach from the glandular portion, but it may occur in any one or all parts of the fore-stomach.