Executive functions in aphasia: A novel aphasia screening for cognitive flexibility in everyday communication.

Besides language deficits, persons with aphasia can present with impairments in executive functions such as cognitive flexibility. Since these impairments can restrict communicative abilities, diagnostics for aphasia should include their assessment. However, tests of executive functions, including symptoms expressed in everyday communication, are lacking for aphasia. Thus, our aim was to fill this gap and study the basic psychometric properties of the novel Cognitive Flexibility in Aphasia Screening. For a pilot evaluation, 26 German patients were examined with tests for language and cognitive flexibility as well as the novel screening. Moreover, 20 non-aphasic persons conducted the latter. We performed a Receiver Operating Characteristic analysis to investigate specificity and sensitivity, and multidimensional scaling to examine similarities between the screening and language/cognitive skills. We found good specificity and sensitivity and showed that the screening is correlated with language skills and verbal cognitive flexibility, revealing promising construct validity and feasibility of the new screening.

Clinical aspects of CRNA practice. Regional anesthesia.

Regional techniques have become increasingly popular for anesthesia and analgesia for surgical patients. It is also frequently used for the patient with nonsurgical pain such as cancer. New discoveries in physiology, pharmacology, pain modulation and transmission as well as pain management therapies are a dynamic field of study in regional anesthesia and analgesia. Nurse-anesthetists provide regional techniques as part of their armamentarium of clinical skills.

Endoproteolysis of presenilin 1 and accumulation of processed derivatives in vivo.

The majority of early-onset cases of familial Alzheimer's disease (FAD) are linked to mutations in two related genes, PS1 and PS2, located on chromosome 14 and 1, respectively. Using two highly specific antibodies against nonoverlapping epitopes of the PS1-encoded polypeptide, termed presenilin 1 (PS1), we document that the preponderant PS1-related species that accumulate in cultured mammalian cells, and in the brains of rodents, primates, and humans are approximately 27-28 kDa N-terminal and approximately 16-17 kDa C-terminal derivatives. Notably, a FAD-linked PS1 variant that lacks exon 9 is not subject to endoproteolytic cleavage. In brains of transgenic mice expressing human PS1, approximately 17 kDa and approximately 27 kDa PS1 derivatives accumulate to saturable levels, and at approximately 1:1 stoichiometry, independent of transgene-derived mRNA. We conclude that PS1 is subject to endoproteolytic processing in vivo.

Subjective experiences of anesthesiologists undergoing epidural anesthesia.

BACKGROUND AND OBJECTIVES: This study reports subjective experiences of nine anesthesiologists undergoing three consecutive epidural anesthetics. METHODS: Eight anesthesiologists and one nurse anesthetist, all ASA physical status 1, underwent three lumbar epidural anesthetics as part of another study. Epidural catheters were inserted via a 17-gauge Tuohy needle without sedation after local anesthesia with pH adjusted lidocaine at the second, third, or fourth lumbar interspace. Three local anesthetics (2% lidocaine HCl, 3% chloroprocaine HCl, and 0.75% bupivacaine HCl) were administered each separated by at least 48 hours. The local anesthetic was incrementally injected via the epidural catheter to achieve at least a T-1 dermatome level of analgesia. Each subject completed a written questionnaire at the end of the study regarding their experience. RESULTS: Most of the subjects (7 of 9) had no prior epidural anesthesia. Eight of nine subjects experienced at least one paresthesia during catheter insertion; this was uniformly described as a "poorly localized burning sensation," radiating to the hip or leg. All subjects reported difficulty taking a deep breath and coughing with a T-1 level of analgesia. Eight of nine subjects reported dysphoria during lidocaine epidural anesthesia. Eight of nine subjects reported moderate back pain after dissipation of chloroprocaine epidural anesthesia. CONCLUSIONS: All volunteers stated that they would change their anesthetic practice as a result of participation in this study. They believed that having experienced an epidural anesthetic made them better qualified to prepare patients for this anesthetic technique.

Does the choice of local anesthetic affect the catecholamine response to stress during epidural anesthesia?

BACKGROUND: Previous work has established that 2-chloroprocaine epidural anesthesia has no effect on circulating plasma epinephrine concentrations in young, healthy, resting volunteers, and results in a decrease in norepinephrine concentration only when a level of analgesia to pinprick of C-8 is reached. The current study was performed to evaluate the possibility that this finding is unique to 2-chloroprocaine. METHODS: Nine healthy volunteers were studied on three occasions at least 48 h apart; each received three local anesthetics (0.75% bupivacaine, 2% lidocaine, and 3% 2-chloroprocaine, all without epinephrine). After placement of lumbar epidural and central venous catheters, blood samples were drawn from the central venous catheter at the following stages: (1) 20 min after catheter placement (baseline), (2) during the first cold pressor test (CPT; hand held in an ice water bath for 90 s), (3) 20 min after reaching epidural analgesia to T-1 level of analgesia, and (4) during a second CPT (epidural analgesia to T-1). Monitoring consisted of noninvasive cardiac output (impedance), noninvasive blood pressure, and EKG. RESULTS: Extensive epidural block (stage 3) altered measured variables only minimally with respect to resting baseline state. During stage 2 (first CPT), mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), epinephrine, and norepinephrine increased. During stage 4 (second CPT), increases in HR and CI were not attenuated by any of the three local anesthetics. Increases in MAP were attenuated by epidural anesthesia with all three local anesthetics. Bupivacaine and 2-chloroprocaine epidural anesthesia significantly attenuated increases in plasma catecholamines, but lidocaine epidural anesthesia did not. CONCLUSIONS: Epidural anesthesia with all three local anesthetic agents tested resulted in an incomplete sympathectomy in the resting state in healthy young men, judged by plasma catecholamine concentrations and cardiovascular variables minimally changed from resting baseline. Lidocaine epidural anesthesia did not attenuate the catecholamine response to CPT, indicating decreased blockade of sympathetic efferent neural traffic compared with bupivacaine and chloroprocaine epidural anesthesia.

The "learning curve" in the performance of laparoscopic cholecystectomy.

Laparoscopic cholecystectomy was successfully performed on 23 of the first 28 patients in whom this was attempted (82.1%). After the first ten cases, the success rate increased to 94.4%. There was only one major complication which prolonged hospital stay but did not require re-operation. Operative time decreased markedly from a mean of 160 minutes for the first ten cases to 61 minutes for the remainder. This increase in operative speed was not accompanied by an increase in complications, in spite of a liberalization of patient selection criteria. It is clear that a steep "learning curve" exists for this procedure and must be recognized and appreciated if laparoscopic cholecystectomy is to become a safe and efficient procedure.

Preoperative evaluation of the patient for regional anesthesia.

The preoperative evaluation of the surgical patient is important for optimizing the anesthetic management. The evaluation process for the regional anesthesia candidate is reviewed. Patient selection, a review of organ systems, and the impact of medications and selected diseases are also discussed.

Sedation and analgesia techniques for regional anesthesia.

The use of adjuvant drugs for regional anesthesia may be indicated for a variety of reasons. Some general patient considerations, indications for the commonly used sedatives and analgesics, and administration techniques for these agents for patients having regional anesthesia are discussed.

Differential epidural block.

BACKGROUND AND OBJECTIVES: Loss of sensation to pinprick and cold are commonly used to test the extent of epidural anesthesia. To see what difference exists between the level of epidural block determined by various sensory modalities, we performed this study in ten volunteers using epidural anesthesia with plain 3% chloroprocaine hydrochloride. METHODS: Four injections of chloroprocaine were made via an epidural catheter inserted at L2-3 with increasing larger volumes. Sensory modalities tested were (1) absence of sensation when tested by pinprick (anesthesia), (2) loss of a sharp sensation compared to an unblocked dermatome when tested by pinprick (analgesia), and (3) loss of cold sensation when tested with an alcohol swab compared to an unblocked dermatome. RESULTS: At 20 minutes after each injection the level of anesthesia was found to be most caudad and the level of analgesia most cephalad. The zone of differential block was greater than four dermatomes at the highest level of block tested. The level of loss of cold sensation was found between the other two levels. Differences between the levels of analgesia and cold sensation tended to be greater with more extensive block. Differences between levels of anesthesia and cold sensation did not significantly change as the extent of epidural anesthesia was increased. CONCLUSIONS: This study establishes the existence of a differential epidural anesthesia during high thoracic block with chloroprocaine and suggests that the intensity of block diminishes as distance from site of injection increases.

Changes in human plasma catecholamine concentrations during epidural anesthesia depend on the level of block.

To test the hypothesis that increasing levels of epidural analgesia will produce progressive decreases in circulating catecholamines, we sequentially produced three levels of analgesia, T8, T4, and C8, to pin prick in young, healthy volunteers. Three percent chloroprocaine (plain) was used as the local anesthetic. The epidural analgesia was allowed to dissipate following the T8 and T4 levels of block. After the C8 level the block was reinforced to study the effect of a "top-up" dose. Blood samples were drawn from a central venous catheter. Plasma concentrations of norepinephrine and epinephrine were determined by the single isotope radioenzymatic method. Despite extensive block, hemodynamic alterations were minimal, and no significant decrease in plasma epinephrine was observed as the level of analgesia was raised to the C8 dermatome. When the level of analgesia was raised above T8, there was a trend for norepinephrine to decrease, but this decrease did not become statistically significant until analgesia reached the C8 dermatome. Reinforcing the epidural block at the C8 level of analgesia resulted an insignificant decrease in epinephrine and norepinephrine NE. Under the conditions of the present study, epidural block with a sensory analgesia level as high as C8 did not significantly decrease the plasma concentration of epinephrine in unstressed volunteers. The plasma concentration of norepinephrine significantly decreased only when the level of sensory analgesia was approximately C8.

Intrathecal morphine does not reduce minimum alveolar concentration of halothane in humans: results of a double-blind study.

The effect of intrathecal morphine on the minimum alveolar concentration (MAC) of halothane was investigated in 22 patients undergoing elective abdominal surgery. The patients were randomly assigned to the control (CTRL) or intrathecal morphine sulfate (ITMS)-treated groups. Approximately 2.5 h before induction of anesthesia with halothane, the ITMS-treated group received 15 micrograms/kg preservative-free ITMS (Duramorph; Elkins-Sinn, Cherry Hill, NJ) while in the right lateral decubitus position. The CTRL group was treated in an identical fashion except that, after placement of the introducer needle, actual dural puncture was omitted. After inhalational induction with halothane as the sole anesthetic agent, the patients' responses to surgical incision were recorded. MAC was determined with the modified up-down method of Dixon and verified with probit analysis. MAC (+/- SE) after ITMS was 0.76 +/- 0.06, compared with a CTRL MAC of 0.78 +/- 0.15 (not significant). Under the conditions of this study, the MAC of halothane in humans was not significantly affected by ITMS.

The effect of pH adjustment of 0.5% bupivacaine on the latency of epidural anesthesia.

pH adjustment of lidocaine and 2-chloroprocaine has been reported to decrease the latency of epidural anesthesia (EA). The effect of alkalinization of bupivacaine on onset of surgical anesthesia has not been adequately studied to date. To determine what effect raising the pH of 0.5% bupivacaine has on the latency of EA in patients undergoing lower extremity surgery, we performed a randomized, double-blind study. Forty patients were randomly divided into two groups. Group I patients received 15 ml of a local anesthetic (LA) solution containing 0.5% bupivacaine and 0.15 mEq of NaHCO3. Group II patients received 15 ml of a standard solution of 0.5% bupivacaine. Both solutions contained freshly added epinephrine (1:200,000). After injection of LA via Tuohy needle, sensory testing was conducted using a safety pin. The pH of the LA used for Group I was 6.96 +/- 0.01 and for Group II was 5.33 +/- 0.11. No statistically significant difference was found between the anesthetic parameters tested in each group. On this basis, we find no advantage of pH adjustment of 0.5% bupivacaine for EA.

Effects of fructose and glucose preloads on subsequent food intake.

To determine how the nutrient content of one eating event might affect amount consumed at the next, we evaluated whether equicaloric fructose and glucose preloads differentially influence subsequent food intake. Subjects consumed 50 g of glucose or fructose in 500 ml of water or water alone and were given a "buffet" containing a variety of foods two and a quarter hours later. Subjects in glucose conditions ate, on the average, 252 X 7 calories more than subjects in the water condition, who in turn ate, on the average, 225 X 9 calories more than subjects in the fructose condition. The fructose and glucose preloads did not differentially affect the amount eaten of different types of nutrients (carbohydrate, fat and protein). This study, employing several sensory and cognitive controls, suggests that type of nutrient ingested, in and of itself, plays a role in determining subsequent intake for humans. The data are discussed in terms of possible physiological mechanisms that might account for these effects.

Dynamics of globular clusters.

In their attempt to reach kinetic equilibrium, through gravitational encounters between separate stars, globular clusters are driven to destruction, with their cores collapsing and their outer regions expanding. The effects of core collapse, which apparently produces x-ray sources, are not yet fully understood, but white dwarfs and neutron stars, probably in binary systems, are thought to be involved, and possibly black holes as well.

Environmental determinants of memory improvement in late adulthood.

Two studies were conducted with nursing home residents to determine whether memory could be improved. This was accomplished by increasing the cognitive demand of the environment and then varying the extent to which residents were motivated to attend to and remember these environmental factors. In Study 1, motivation to practice recommended cognitive activities was manipulated by varying the degree of reciprocal self-disclosure offered by interviewers in a series of dyadic interactions. In Study 2, motivation to practice recommended cognitive activities was manipulated by varying whether positive outcomes were contingent on attending to and remembering these activities, which increased in demand over time. Whether as a function of interpersonal (Study 1) or practical (Study 2) incentives, engaging in cognitive activity resulted in improvement on standard short-term memory tests, including probe recall and pattern recall, as well as in improvement on nurses' ratings of alertness, mental activity, and social adjustment for experimental groups relative to controls.