An electrophysiological study of boundary conditions for control of recollection in the exclusion task.

Event-related potentials (ERPs) were collected in a memory retrieval task that was designed to assess the resolution with which people exerted control over memory retrieval. Participants were first required to indicate whether the objects denoted by concrete nouns (i) had pleasant or unpleasant connotations, (ii) were typically smaller or larger than a shoebox, or (iii) were easy or difficult to draw. They then completed a retrieval task where old (studied) and new words were presented. Participants pressed one key for words encountered in the drawing task, and a second key for all other test words (new words as well as those encountered in the pleasantness and size judgment tasks). The left-parietal ERP old/new effect--an electrophysiological index of recollection--was reliable for words from the drawing task only. This finding is consistent with the view that participants were successful at prioritising recollection of some kinds of information over others. The data also provide an insight into the resolution with which this prioritisation can be implemented, because there was little evidence of a left-parietal ERP old/new effect for words to which a size judgment was made, despite the fact that visual imagery is likely to have been employed for drawing as well as for size judgments.

Bone marrow transplant today--home tomorrow: ambulatory care issues in pediatric marrow transplantation.

Pediatric marrow transplantation is now an accepted and increasingly successful intensive therapy for a wide range of disorders in children. Supportive therapies that were once thought to be possible only in the acute care setting can now be safely managed in the outpatient arena. This shift is influenced by scientific and patient care advances and by managed care and cost containment trends. The purpose of this article is to examine the interrelated aspects of change in health care delivery and their impact on pediatric bone marrow transplant recipients and families. Nurses working in all aspects of pediatric marrow transplantation have an opportunity and responsibility to impact quality patient care in the outpatient setting.

Kochia (Kochia scoparia) toxicosis in cattle: results of four experimental grazing trials.

Four kochia grazing trials were completed over a period of 3 years. Yearling steers were allowed to graze pure stands of irrigated and fertilized kochia (Kochia scoparia) for periods of 14 to 105 days. A total of 116 steers were given kochia as their sole forage. Twenty control steers were allowed to graze native grass pasture, and 20 steers were allowed to graze both native grass and kochia pastures. Steers grazing only kochia lost weight or gained poorly compared with control steers grazing native grass. Steers that grazed both kochia and native grass had intermediate rates of gain. Signs of toxicosis were observed only in steers grazing kochia alone. Considerable variability in the degree of toxicosis was observed from one year to another. Morbidity in the steers grazing only kochia varied from 0% (Trial 4) to 28% (Trial 1), and mortality varied from 0% (Trials 3 and 4) to 10% (Trial 2). The most common signs observed in clinically affected steers were depression, dehydration, weight loss, muscular weakness, photosensitization, ocular discharge, and crusty muzzle. In all 4 trials, significant elevations in serum glutamic oxaloacetic transaminase (GOT) and serum gamma glutamyl transpeptidase (GGT) were observed in steers grazing kochia. In 3 of the 4 trials, significant elevations in serum bilirubin, serum calcium, and serum protein were also observed in kochia-fed steers. Necropsies were performed on 6 of 9 steers that died or were euthanized. The primary pathologic findings were severe chronic nephrosis (5 steers) and degenerative hepatopathy (5 steers).(ABSTRACT TRUNCATED AT 250 WORDS)

Taking charge of high-tech equipment purchases.

Today's rising operating costs and declining revenues have focused attention on the importance of materiel managers in influencing their hospital's struggle to balance fiscal responsibility with the need to remain in step with advancing technology. This change in the status has left some materiel managers still struggling to find ways to fulfill the expectations of their hospital's administration and many members of the staff. One way materiel managers can respond is by taking the lead in establishing a strategic planning mechanism for capital equipment purchases; by insisting that equipment purchase decisions be made in the context of the whole hospital; by insisting that purchase decisions look beyond price to return on investment; and by insisting that each acquisition be a worthwhile, long-term investment for the hospital. The obvious justification for these demands is that they make economic sense.

Comparison of four serotests for the detection of Dirofilaria immitis infection in dogs.

Three hundred two dogs were tested with 4 serotests for heartworm antigen (AG) or antibody (AB) and with the Knott test. The 4 serotests evaluated were an enzyme-linked immunosorbent assay (ELISA) for adult heartworm-specific AB (AB-ELISA), a quantitative, indirect immunofluorescent assay (IFA) for adult heartworm-specific AB (AB-IFA), an IFA test for microfilaria (MF)-specific AB (MF-IFA), and an ELISA for adult heartworm AG (AG-ELISA). The presence of heartworms was ascertained in all dogs by necropsy examination. Of 302 dogs, 20 (6.6%) had heartworms in the heart at necropsy. Of infected dogs, 9 (45%) had occult infections. Test sensitivities were 75%, 95%, 70%, and 75% for the AB-ELISA, AB-IFA, MF-IFA, and AG-ELISA, respectively. Test specificities were 85% (AB-ELISA), 77% (AB-IFA), 87% (MF-IFA), and 99% (AG-ELISA). The best agreement between serotest results and necropsy findings was obtained with the AG-ELISA (97%). The 4 serotests detected 86% (AB-ELISA), 100% (AB-IFA), 67% (MF-IFA), and 78% (AG-ELISA) of the dogs with occult heartworm infection. A significant (P less than 0.05) association between intestinal parasitism and positive heartworm test results was found with only AB-IFA. Seemingly, the Knott test, or some other concentration method for detecting circulating MF should be the first heartworm test performed. If the examination for MF is negative, the dog has clinical signs, and radiographic findings are suggestive of occult heartworm infection, then a serotest for adult heartworm AG is recommended.

Five-month oral (diet) toxicity/infectivity study of Bacillus thuringiensis insecticides in sheep.

Bacillus thuringiensis insecticides (Bt) [Dipel (test substance D or Thuricide-HP (test substance T)] were administered in the diet for 5 months to castrated mixed rambouillet/merino sheep (24-34 kg at the beginning of the study) at a dose of 500 mg/kg/day (approximately 10(12) spores per day). No treatment-related effect was seen on weight gain or clinical chemistry parameters nor were significant gross clinical changes observed. Several blood and tissue samples taken just prior to the time the animals were killed or at necropsy were found to be positive for Bt when cultured. Detailed gross and microscopic pathologic examination of the sheep revealed several incidental lesions. However, the only lesion that may have been associated with the treatment was lymphocytic hyperplasia in Peyer's patches seen in the cecum of three sheep and it was not considered to be clinically significant.

Infusion therapy devices: selection, cost and maintenance.

Each healthcare facility must formulate and justify their policies and procedures for providing infusion therapy. The materials manager and/or central supply manager should be involved in this process. Each facility must address and define its own specific applications and justify the decisions within the respective medical, nursing, technical and administrative staffs. Furthermore, the facility's policy and procedures should not be static. They must be reviewed and upgraded at regular intervals because of the changes in medical technology and pharmacology. Proper understanding of the definitions addressed in this article will assist in simplifying committee decisions and provide for a more comprehensive and rational policy.

Development and evaluation of electrically actuated abdominal left ventricular assist systems for long-term use.

A long-term, totally implantable, electrically actuated, abdominally positioned left ventricular assist system (ALVAS) is being developed, characterized in vitro, and evaluated in vivo for utilization in patients with end-stage cardiac failure refractory to conventional therapeutic techniques. The first two major subsystems of the ALVAS (the pusher-plate blood pump and electrical-mechanical energy converters) have been integrated and are undergoing in vitro characterization and long-term in vivo evaluations in calves. Duration of these studies has exceeded 6 months. System performance in terms of hemodynamic effectiveness, mechanical reliability, and biocompatibility has been excellent and no untoward effects have been observed. Long-term effectiveness of the ALVAS remains to be established in continuing experiments, with a 2 year period of clinical use as an ultimate goal.

RIGHT AND LEFT VENTRICULAR HEMODYNAMIC INDICES AS PREDICTORS OF THE NEED FOR AND OUTCOME OF POST-CARDIOTOMY MECHANICAL INTRAAORTIC BALLOON PUMP SUPPORT.

Preoperative cardiac catheterization data of 21 patients requiring intraaortic balloon pumping (IABP) for weaning from cardiopulmonary bypass were analyzed and compared with similar data in 28 patients who underwent nearly similar operative procedures, but did not require IABP for weaning. Cardiac index (CI) and systemic vascular resistance (SVR) were found to have predictive value for the need of IABP for weaning from cardiopulmonary bypass and differentiated survival from non-survival. Left ventricular end diastolic pressure (LVEDP) was not found to be predictive. Ejection fraction (EF) was significantly lower in those who required IABP than those who did not; EF did not predict the outcome. Pulmonary capillary wedge pressure ([unk]), pulmonary artery pressure ([unk]) and pulmonary vascular resistance (PVR) were predictive of the need for IABP, but not the outcome. Left ventricular minute work index (LVMWI) was significantly lower in those requiring IABP, right ventricular minute work index (RVMWI) was predictive of survival with IABP. Together, LVMWI and RVMWI were predictive of the need for and outcome of IABP following cardiopulmonary bypass. Twenty-seven of 28 control RVMWI's were normal. No patient requiring IABP had depressed RVMWI's preoperatively. Elevated preoperative RVMWI's were associated with 80% survival with postcardiotomy IABP; normal RVMWI's were associated with a 56% survival with post-cardiotomy IABP. Elevated preoperative RVMWI's reflected moderate to maximal right ventricular compensatory capacity in response to depressed left ventricular function. Normal preoperative RVMWI's in the presence of depressed LVMWI's were indicative of decreased right ventricular compensatory capacity in post-cardiotomy IABP-support settings. Right ventricular function is as important as left ventricular function as a prognosticator for the need and outcome of IABP support of the failing post-cardiotomy circulation.

CLINICAL TRIALS OF THE ABDOMINAL LEFT VENTRICULAR ASSIST DEVICE (ALVAD): PROGRESS REPORT.

An abdominal left ventricular assist device (ALVAD) is undergoing controlled clinical trials in our institution. The ALVAD is pneumatically-actuated, synchronously or asynchronously with an external console and is interposed between the apex of the left ventricle and the infrarenal abdominal aorta. It is an order of magnitude more effective than conventional intraaortic balloon pumping. Thus far, we have implanted this pump in 21 patients (15 males and six females). The average age has been 50. The duration of cardiopulmonary bypass with intensive pharmacologic support and IABP until ALVAD implantation has been nearly 4 hours. The plasma hemoglobins prior to ALVAD implantation have averaged 168 mg%. The platelet counts at implantation have averaged 68,000 mm(3). The average duration of ALVAD support has been in excess of one day and the longest trial extended for one week. We have been able to remove the pump after ventricular recovery in two instances and effected cardiac allografting in one instance of ALVAD dependency. We have found that (1) the profoundly depressed left (and right) ventricles can recover if totally supported with this device; (2) the device can function in the presence of ventricular fibrillation and/or standstill; (3) the device can effectively replace both left and right ventricular function in the presence of normal pulmonary vascular resistance and microcirculatory hemodynamics; and (4) in the presence of impending multiple organ failure, procrastination in use is to be avoided.

PREFABRICATION DESIGN CONSIDERATIONS FOR A LONG-TERM ELECTRICALLY-ACTUATED ABDOMINAL LEFT VENTRICULAR ASSIST DEVICE (E-TYPE ALVAD).

The conceptual design and development of a long-term, low-profile intracorporeal left ventricular assist device is a multifaceted project involving a series of technical, anatomic and physiologic considerations. Patients with severe left ventricular failure refractory to all other forms of therapy could benefit from such a device. Prior to fabrication of such a blood pump, consideration must be given to physiologic parameters of the projected patient population. The pump must be designed to meet physiologic demands and yet conform to the anatomic constraints posed by the patient population. We measured the body surface area (BSA) of a group of patients (n=50) and found the mean BSA for this group to be 1.804 +/- 0.161 m(2). Using 25 ml/m(2) as a stroke volume index indicative of left ventricular failure and a stroke volume index of 45 ml/m(2) as normal, distributions of stroke volumes (normal and in left ventricular failure) were plotted for a potential population and demonstrated that 63% of the projected population can be returned to normal by a pump with a stroke volume >/= 83 ml. Cadaver fitting studies established that 73% of the potential population can accommodate an ALVAD 10.8 cm in diameter. In-vitro tests demonstrated that a pump stroke volume >/= 83 ml could be achieved by the proposed pump with a 15 mmHg filling pressure at rates up to 125 B/min. A pusher-plate stroke of 0.56 inches would be necessary to provide a stroke volume >/= 83 ml. The percent of the patient population that could be served was determined by excluding those in whom the pump would not fit or in whom it would provide less than a normal resting stroke volume. Approximately 73% of the projected patient population would accommodate this pump and be returned to normal circulatory dynamics.