Rats subjected to a brief anoxia can survive go sec in a second anoxia, compared to a 60-sec survival time of control animals. Slower disappearance of ATP concentration in the brain during the second exposure indicates this longer survival is due to an altered cerebral energy metabolism. Initial cerebral ATP concentration is no higher in pre-exposed animals than in controls. When glycolysis is inhibited by iodoacetate before testing in anoxia, the advantage of pre-exposure disappears, suggesting the longer survival may be due to increased anacrobic glycolysis. Lactate accumulates faster during anoxia in the brains of pre-exposed animals than in controls, suggesting that increased anaerobic glycolysis is the cause of the prolonged survival. This effect is not due to increased cerebral glucose concentration. A possible reason for this increased glycolysis, and thus the prolonged survival, could be an increase of a compound, such as pyruvate, capable of oxidizing NADH. The initial pyruvate is higher in pre-exposed animals than in controls and injection of pyruvate increases the survival time slightly.

That the short chain fatty acids have an inhibitory action on many metabolic reactions has been shown in baker's yeast (1), bacteria (2-4), fungi (5), cell-free yeast extracts (1), and mammalian muscle (6). However, the effects of the short chain fatty acids on "intact" animals have not been studied in similar detail, except for a few studies on the toxicity of butyrate (7), ,-hydroxybutyrate (8, 9), acetone (10) and acetoacetate (11). The present work is a study of the narcotic action of the neutralized salts of the short chain fatty acids upon "intact" rats. METHODSSolutions of the fatty acid salts were prepared daily by adding a weighed amount of the acid (Fisher Scientific Co.) to distilled water and neutralizing it to a pH of 7.4 with 20 per cent w/v NaOH. The pH was determined with a glass electrode pH meter while air bubbled through the solution to insure adequate mixing. In this connection, pH determinations are subject to error because these acids tend to form two phase systems and colloidal gels. In the present experiments care was taken to neutralize all the free fatty acid and only homogeneous preparations were used. The concentration of the fatty acid anion is specified in the individual cases. The f-hydroxybutyrate was purchased as the sodium salt (Nutritional Biochemical Corp.) and solutions were prepared by dissolving a weighed amount in distilled water and bringing it to a pH of 7.4.The rats used in these experiments were females from a Sprague-Dawley strain maintained on Nutrena@ dog food nuggets and weighing between 50 and 200 grams. They were fasted 24 hours before experimentation and weighed immediately prior to the fatty acid injection. For species comparisons, mice, guinea pigs, dogs, chicks and frogs were used; however, detailed data were collected only with rats.Nephrectomized rats were prepared according to the directions of Farris and Griffith (12). With the animal under ether anesthesia a dorsal midline incision was made, the renal connections isolated and tied off at the hilum, then the kidney excised. With the operation concluded,

• Background Little information is available nationally about critical care units and nurses. What is known about nurses in hospitals is generally not broken down among all the specialties. • Objectives To describe issues of workforce, compensation, and care specific to critical care units and nurses who work in them. • Methods The American Association of Critical-Care Nurses conducted a survey of randomly selected facilities with critical care units in the United States. Facilities were solicited via e-mail to respond to a survey on the World Wide Web and provide information on operations, evaluations, nursing staff reimbursement and incentives, staffing, and quality indicators. Responding facilities also provided contact information for units in the facilities. Those units were surveyed about operations, acuity systems, staffing, policies on visitation and end-of-life care, administrative structure, documentation, certification, professional advancement, vacancy/floating, staff satisfaction, orientation, association membership, wages, advanced practice nursing, and quality indicators. • Results The initial response rate (120 of 658 eligible facilities) was 18.2%, and 300 of 576 solicited units nominated by the facilities responded, yielding a 52.1% response rate for the second phase. • Conclusions These survey data define the scope and intensity of services offered and provide more specific figures about staffing issues and unit practices than has been accessible before. Healthcare providers may use this information for benchmarking purposes, especially for instances in which the tables provide data for each particular type of critical care unit.

The rate of adenosinetriphosphate (ATP) disappearance in the brain after inhibition of aerobic and anaerobic metabolism was investigated. It was found that the rate increases with increasing age in the neonatal rat and that the effect of lowering the body temperature, which slows the rate, is greater in the 21-day rat than in the newborn. Calculation from the data gives 0.5 µm/sec/gm as the rate of high-energy phosphate utilization in the 21-day rat, and 0.04 µm/sec/gm in the 1-day rat. This increase in the rate of energy utilization during neonatal maturation is compared with the capacity to generate ATP; the utilization increase is found to be six times that of the capacity to generate ATP. The Q10 of the high-energy phosphate utilization in the 21-day rat is 1.7 in the 37°–25°C range, but is 10. in the 25°–15°C range. It is concluded that the rate of high-energy phosphate utilization is closely related to the amount of neuronal activity and, further, that the energy cost per average nerve impulse probably is greater in the adult brain than in the neonatal brain.