Branched chain amino acid administration and metabolism during starvation, injury, and infection

Branched chain amino acids were administered intragastrically in a septic-fractured rat model to determine the degree and mechanism of their protein-sparing ability. The septic injury model was first shown to produce a metabolic response characterized by hyperglycemia, reduced ketonemia and increased nitrogen loss. Branched chain amino acids were then administered either alone or as 25% or 50% (w/w) of a complete crystalline amino acid solution. L-(U-14C)-tyrosine was added to the diet to estimate protein synthesis in individual tissues. Branched chain amino acids, when given alone, spared total body nitrogen as compared with fasting by increasing the fractional synthesis of both mixed liver and muscle protein. Although the two complete amino acid mixtures produced similar nitrogen preservation and muscle synthesis in the septic animals, the crystalline amino acid diet containing 50% branched chain amino acids resulted in the greatest preservation of total liver nitrogen and the highest fractional synthetic rate. The effect of branched chain amino acids would not appear to be explained by their nitrogen content alone, and in starvation with injury and infection, increased intakes may have potential benefit. Clinical trials in starved, injured man appear to be indicated.

Growth-stimulating factor in regenerating canine liver

Extracts from dog livers which had been regenerating for 24, 48, and 72 h after hepatectomy were infused for 6 h into the left portal vein of animals which had fresh portacaval shunts (Eck fistula) and which were killed 2 and 3 days later. The brief exposure to the 48-h and especially the 72-h regenerating liver extracts induced a delayed proliferative response predominantly in the left liver lobes, with a slight spillover effect to the right liver lobes but none to the kidney. The response reached its peak 3 days later. In the left but not the right liver lobes, both the 48-h and the 72-h regenerating liver extract reversed the atrophy ordinarily caused by Eck fistula in 3 days and partly prevented the ultrastructural hepatocyte deterioration characteristic of Eck fistula. The active liver extracts apparently contained a growth-control factor or factors which is (are) not insulin or glucagon.

Effects of atropine upon the hippocampal electrical activity in rats with special reference to paradoxical sleep

In freely moving male rats with implanted electrodes, the influence of atropine sulphate (5-30 mg/kg, i.p.) on the hippocampal theta activity was studied with special emphasis on paradoxical sleep (PS). In accordance with previous work with cats and rabbits, atropine was found to inhibit PS, in delaying its first appearance as well as in decreasing the duration of the first PS episode. The hippocampal theta activity during PS was also changed after atropinization. In particular, when REM occurred often, theta activity was increased not only in frequency but also in amplitude; however, with no or little REM, theta frequency was not changed but the regularity of theta rhythms was markedly disturbed. These findings are in contrast with the theta activity associated with gross body movement, which was not affected by atropine as was previous reported by Vanderwolf (1975). Thus, in contrast to commonly held views, the hippocampal theta activity during gross body movement may be different in its underlying mechanisms from that during PS.

Effect of PS-K, a protein polysaccharide, on pulmonary metastases of a C3H mouse squamous cell carcinoma

We studied the effects of PS-K, a protein polysaccaride isolated from a basidiomycete, on the formation of blood-borne metastases. Experimental tumors were fifth-generation isotransplants of a spontaneous C3Hf mouse squamous cell carcinoma that was weakly antigenic. A single-cell suspension from fourth generation tumors was transplanted, and the tumor-bearing legs of the mice were amputated when transplants reached a certain diameter. Daily administrations of PS-K followed immediately, and both lungs were excised on the 21st postamputation day. The number of lung colonies formed on the surfaces of both lungs was counted and total volumes of metastatic colonies were estimated. PS-K, if administered alone, did not inhibit the lung colony formation. Marked reduction in this formation was observed when five daily doses of PS-K were administered simultaneously with cyclophosphamide. These observations indicate that PS-K may be a potent agent in the therapy of cancer if used as an adjuvant to a chemotherapeutic agent.