THE EFFECT OF PORTA-CAVAL ANASTOMOSIS UPON THE ENERGY STATE AND UPON ACID-BASE PARAMETERS OF THE RAT BRAIN

Abstract— In order to evaluate the influence of porta-caval anastomosis upon the energy state of the brain, lightly anaesthetized rats were studied either 1 or 5 weeks after the shunting procedure and the brains (frontal lobe, cerebellum and brainstem) were analysed for carbohydrate substrates and organic phosphates. The ammonia contents of arterial blood, cerebrospinal fluid (CSF) and tissue increased progressively in the shunted groups and at 5 weeks the increases were three- to six-fold. In all brain structures studied there were decreases in the glucose and in the aspartate contents but regional differences existed for glucose-6-phosphate, α-ketoglutaratc and glutamate. In the brainstem the tissue contents of glucose-6-phosphate and α-ketoglutarate fell while glutamate was unchanged. Calculation of the cytoplasmatic redox state from the lactate dehydrogenase (LDH) and the malate dehydrogenase (MDH) equilibria indicated that the NADH/NAD⁺ ratio increased in the shunted groups. However, since there was no significant fall in the calculated adenylate energy charge, it is concluded that porta-caval anastomosis, and the accompanying hyperammonemia, do not disrupt the balance between production and utilization of energy in the brain.     

THE INFLUENCE OF ALCOHOL UPON THE GROWTH OF SEEDLINGS

In this paper it is shown that if the dry seeds of the cantaloupe (Cucumis melo) are soaked for 3 hours in solutions of ethyl alcohol of concentration ranging from 2 to 16 per cent by volume, and then germinated and grown in distilled water in the dark, the total growth attained is greater by amounts ranging from 9 to 35 per cent than is that made by seeds treated in every way identically except that they are initially soaked in distilled water instead of alcohol. It is shown that this result is not due simply to differences in osmotic pressure in the different alcohol solutions. It is probably due to a simple selective action of the alcohol which eliminates the constitutionally weak and defective seeds.     

THE EFFECT OF TEMPERATURE UPON SOME OF THE PROPERTIES OF CASEIN

1. The investigations dealing with the properties of casein as an acid were reviewed. 2. The solubility of uncombined casein in water was measured at 5°C. and found to be 0.70±0.1 mg. of N per 100 gm. of water. 3. Robertson''s solubility measurements of casein in bases at various temperatures were recalculated and found to agree well with more recent measurements. 4. By combining the observations of several investigators, as well as the author''s measurements of the solubility of casein, in base, at various temperatures, the following conclusions were reached: (a) The solubility of casein in base is affected by the temperature in a discontinuous manner. (b) There exist two ranges of temperature, one, extending from about 21° to 37°C. and the other from about 60° to 85°C. where the solubility of casein in base is practically independent of temperature. (c) From 37° to 60° the equivalent combining weight of casein rises from the value 2100 to about 3700 gm. 5. By comparing the values of base bound by 1 gm. of casein at the two temperature ranges with a constant, the value of base necessary to saturate the same amount of casein, it was found that the latter value is a common multiple of the former values, indicating the stoichiometric nature of the effect of temperature.