The effect of epinephrine on small-dose hyperbaric bupivacaine spinal anesthesia: clinical implications for ambulatory surgery

The effect of adding epinephrine to small doses of spinal bupivacaine on the duration of sensory motor block has not been carefully investigated. Twelve volunteers underwent hyperbaric bupivacaine spinal anesthesia (7.5 mg) with and without epinephrine (0.2 mg) in a randomized, double-blind, cross-over fashion. Sensory block was assessed with pinprick, transcutaneous electrical stimulation (TES) equivalent to surgical stimulation (at umbilicus, pubis, knee, and ankle), and tolerance of a pneumatic thigh tourniquet. Motor block was assessed with isometric force dynamometry. Discharge criteria were defined as return of pinprick sensation to dermatome S2, ability to ambulate, and ability to urinate. Extent of sensory block to pinprick over time was unaffected by the addition of epinephrine. However, epinephrine prolonged tolerance of TES at the pubis, knee, and ankle (33-48 min, P < 0.05) and of thigh tourniquet (30 min, P < 0.01). Motor block was prolonged by epinephrine at the quadriceps and gastrocnemius muscles (by 23 and 51 min, respectively, P < 0.002). Achievement of discharge criteria was prolonged by 48 min by the addition of epinephrine (P < 0.01). Thus, epinephrine may prolong surgical anesthesia for lower abdominal and lower extremity surgery and delay time until patients achieve discharge criteria. Implications: Using a cross-over study design, 12 volunteers underwent bupivacaine spinal anesthesia with and without epinephrine. This study suggests that adding epinephrine to bupivacaine may prolong surgical anesthesia and also delay patients' discharge.     

T-Waves in the Exercise ECG: Their Location and Occurrence

The automated location of T-wave fiducial points in single lead exercise ECG's is facilitated by using R-Tmax and R-Tend intervals predicted from heart rate. Predictive equations for these intervals were developed; algorithms were subsequently designed and tested on 8380 averaged ECG beats from 146 patients. Of 6775 ECG beats with monophasic T-waves, 98 percent of Tmax and 96 percent of Tend fiducial points were correctly identified by these algorithms. The predictive equations and associated algorithms are discussed.     

Is there a special flashbulb-memory mechanism?

Many people report vivid recollections of the circumstances in which they learned of major events, such as the assassination of President Kennedy, or the assassination attempt on President Reagan. Brown and Kulik (1977) argued that this phenomenon, which they labeled flashbulb memory, implies the existence of a special memory mechanism that creates a detailed, permanent record of the individual's experience when triggered by an event exceeding criterial levels of surprise and consequentiality. In this article we evaluate the special-mechanism hypothesis, arguing on empirical and logical grounds that the flashbulb-memory phenomenon does not motivate the postulation of a special flashbulb-memory mechanism. We suggest instead that flashbulb memories should be viewed as products of "ordinary" memory mechanisms, and hence as phenomena that may offer insights into the nature of these mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object request broker: Foundation for distributed simulation

Real-time, human-in-the-loop simulation of air traffic control is naturally distributed across computing platforms because of the need for many input and display devices, the need for computing power, and the need to integrate legacy simulations that run on a variety of platforms. Object orientation has a long history of fruitful application to simulation problems, including real-time simulation. Thus there is great interest in commercial products for distributed object management. We have examined the suitability of object request broker (ORB) technology for simulation control, i.e. applications-as-objects, and for supporting truly object-oriented, distributed, real-time simulation. Our experience with DEC's ORB shows that at present the former is feasible but the latter is probably not; however the available implementations are changing rapidly. ORB technology can also bring the distributed interactive simulation (DIS) protocol of the DoD into an object-oriented framework.     

Microcomputer vs. mainframe simulations: A case study

A comparison was made between using a simulation language to run models on a mainframe computer and on a microcomputer with a hard disk. The study was performed at NASA Langley using both the SLAM II mainframe and PC versions. The procedure for executing SLAM II on a PC is given. A batch job was created to simplify this procedure and allows PCs with a hard disk to execute simulations with one command. NASA's space transportation system operations model and the examples in the SLAM II text were used as a basis for the comparison. The PC simulations completed in predictable times. These were almost always faster than the more unpredictable mainframe times.     

Sex and race composition of assessment center groups as a determinant of peer and assessor ratings.

Evaluated the effects of sex and race composition of assessment center groups on assessment center ratings for 54 racially and sexually mixed groups. Results indicate that there were minimal effects as a result of the race–sex composition of the group, but some assessment ratings for Black females were negatively and significantly correlated with the number of White males in the assessment group. The ratings of White males tended to be higher when the number of White males in the assessment group increased. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of pre-treatment with phenobarbitone on the activation of aflatoxin B1 by rat liver

Microsomes prepared from rats pre-treated with phenobarbitone are more effective in activating aflatoxin B1 in vitro to a metabolite which inhibits RNA polymerase than are microsomes obtained from control animals. This result is in contrast with the situation in vivo where pre-treatment with phenobarbitone protects against inhibition of RNA synthesis by aflatoxin B1. The hypothesis is advanced that, in vivo, the activation of aflatoxin B1 which is significant in terms of inhibition of nucleic acid synthesis largely occurs on the outer nuclear membrane, and that by increasing activation by the microsomes, phenobarbitone pre-treatment reduces the amount of aflatoxin B1 available for the nuclear activation.