Operations upon the aged

From the point of view of the surgeon, as repeatedly emphasized in the surgical literature, the mortality rate for operations upon old persons is only slightly higher for elective surgical operations than for the same operations on younger persons when proper preoperative and postoperative precautions are taken. However, the mortality rate for emergency operations is much higher in old persons than in younger ones. Many surgeons believe, therefore, that disease for which operation is otherwise indicated should be treated surgically irrespective of the age of the patient per se. The authors' experience with operations upon old persons at the San Francisco Hospital accords with these conclusions.     

Influence of prostaglandins upon adenosine release and of adenosine upon prostaglandin release in the isolated rabbit heart.

Prostaglandin (PG) E1 with its high effect of coronary dilation causes a distinct increase in the adenosine release from the isolated rabbit heart (Langendorff technique). Compared to this, an equal dose of PGF2alpha increases the release of adenosine only to a small extent. Conversely, application of adenosine results in a considerable release of PG-like substances from the rabbit heart in vitro. The present investigations support the hypothesis that, apart from adenosine, PG's too, are involved in coronary regulation as modulators.     

Effects of Cerulenin upon the Syntheses of Lipid and Protein and upon the Formation of Respiratory Enzymes in Adapting, Lipid-Limited Saccharomyces cerevisiae

When bakers' yeast cells were grown anaerobically in a medium supplemented with Tween 80 and ergosterol, exposure during aeration to the fatty acid synthesis inhibitor, cerulenin, had little effect upon respiratory adaptation, the induction of enzymes of electron transport, or the in vivo incorporation of [(14)C]leucine into mitochondrial membranes. These lipid-supplemented cells were apparently able to undergo normal respiratory adaptation utilizing endogenous lipids alone. The level of cerulenin used (2 mug/ml) inhibited the in vivo incorporation of [(14)C]acetate into mitochondrial membrane lipids by 96%. If, however, the cells were deprived of exogenous lipid during anaerobic growth, subsequent exposure to cerulenin severely reduced their capacity to undergo respiratory adaptation, to form enzymes of electron transport, and to incorporate amino acid into both total cell and mitochondrial membrane proteins. This cerulenin-mediated inhibition of enzyme formation and of protein synthesis was nearly completely reversed by the addition of exogenous lipid during the aeration of the cells. In lipid-limited cells, chloramphenicol also had dramatic inhibitory effects, both alone (75%) and together with cerulenin (85%), upon total cell and mitochondrial membrane [(14)C]leucine incorporation. This marked chloramphenicol-mediated inhibition was also largely reversed by exogenous lipid. It is concluded that, in lipid-limited cells, either cerulenin or chloramphenicol may prevent the emergence of a pattern of lipids required for normal levels of protein synthetic activity. The effect of cerulenin upon the formation of mitochondrial inner membrane enzymes thus appears to reflect a nonspecific effect of this antilipogenic antibiotic upon total cell protein synthesis.     

Effects of iodine upon the structure and function of mitochondria

The influence of iodine in its positive and negative monovalent form upon the oxygen consumption in euthyroid and thyroidectomized rats and the oxidative phosphorylation in liver mitochondria isolated from both groups of animals, as well as the spontaneous swelling and total ATPase activity of mitochondria have been studied.It was established that the administration of ICI increased the oxygen consumption of normal and thyroidectomized rats while under the same conditions no effect was found with NaI. IBr stimulated the oxygen consumptionin vitro in liver mitochondria isolated both from normal and thyroidectomized rats and decreased the P/O ratio while NaI had no effect. I₂ and IBr increased the swelling and inhibited the ATPase activity of isolated rat liver mitochondria, while these effects were not observed when KI was used. The thyroidstatic 1-methyl-2-mercaptoimidazol decreased the stimulating effect of iodine upon the swelling of mitochondria and to a certain extent lowered its inhibiting effect upon the ATPase activity.It is concluded that iodine in its positive monovalent form has a thyroxine-like effect upon the structure and function of isolated rat liver mitochondria, as well asin vivo upon the respiration of euthyroid and thyroidectomized rats.     

The effects of undernutrition upon the energy reserve of the brain and upon other selected metabolic intermediates in brains and livers of infant rats

—Rats undernourished from the first to the ninth day of life exhibited no decrease in the energy reserve (P-creatine, ATP, glucose and glycogen) of the brain, although they underwent a 41 per cent decrease in body weight. The apparent increase in the cerebral levels of glucose-6-phosphate and the decreases in hepatic glucose and lactate in the starved animals were probably a consequence of the fact that they froze faster than the control animals rather than of any essential differences in vivo. However, decreases in cerebral glutamate (11 per cent) and hepatic glutamate (33 per cent) in the undernourished animals cannot be explained on this basis. Possible explanations for this decrease in cerebral glutamate content are: a decreased supply of glutamate from the liver, a decreased synthesis of glutamate by the brain, or an increased use of glutamate as an energy source. Since levels of glutamate in the brain increase progressively during the first weeks of life, another interesting possibility is that the lower level of cerebral glutamate in undernourished rats represents a biochemical indicator of a delay in the maturation of specific morphological components which are rich in glutamate and are characteristic of the brain.