Search PubMed⌕ Search

Biomedical subjects

E Snyder

Publications and source records attributed to E Snyder.

52 records · Page 3Linked to original sources
PubMed1976

Auditory evoked potentials during multichannel selective listening: role of pitch and localization cues.

Auditory evoked potentials were recorded from subjects who listened selectively to tone pips arriving over one of three input channels. Their task was to detect occasional target tones of a slightly longer duration. In different runs the three channels were distinguished from one another by (a) pitch cues alone (800, 1,800, and 2,800 Hz), (b) localization cues alone (right ear, midline, ane left ear), and (c) both of these cues conjointly. In all three conditions the direction of attention was reflected in the amplitude of the N1 wave of the evoked potential, which was selectively enhanced to tones in the attended channel; tones in the central channels in the single-cue conditions, however, produced the least N1 lability and were the least discriminable. The N1 wave was interpreted as a sign of an initial stimulus set or filtering mode of selective attention, whereas a subsequent P3 wave was specifically associated with detections of the target stimuli.

Adult↗
PubMed1973

Influence of methodology upon apparent concentrations of antibiotics in tissue.

This study compares the diffusion in agar of antibiotics prepared in homogenates of tissue, tissue supernatant fluids, whole serum, and buffer solution. Penicillin, erythromycin, cephalothin, gentamicin, and colistin sulfate were studied. With the exception of erythromycin in supernatant fluid of human tonsil, zones of inhibition in agar were consistently smaller in homogenate and supernatant fractions of tissue than in serum and buffer. Thus, a significant error of underestimation occurred when a buffer standard curve was used for assaying antimicrobial activity in homogenates of tissue. This error ranged from 23 to 66% in 10% guinea pig liver homogenate and from 43 to 78% in 20% liver homogenate. A similar, but smaller error of under-estimation resulted with supernatant fractions of tissue except with erythromycin, for which a 25 to 56% error of overestimation occurred when activity in supernatant fraction of tonsil was read off a buffer standard curve. These results emphasize the importance of preparing the standard antibiotic curve with material having agar diffusion properties similar to those of the material being assayed.

Animals↗
PubMedDate not supplied

Dorzolamide versus pilocarpine as adjunctive therapies to timolol: a comparison of patient preference and impact on daily life.

The purpose of this study was to compare 2% dorzolamide three times daily with 2% pilocarpine four times daily to determine patient preference, tolerability, and impact on daily life in patients concurrently receiving 0.5% timolol twice daily for treatment of elevated intraocular pressure (IOP). Seventy-five patients were enrolled in this 4-week, randomized, two-period, crossover study. The Comparison of Ophthalmic Medications for Tolerability questionnaire was used to assess patient preference and perception of side effects and activity limitations resulting from the study medications. IOP measurements were obtained 2 hours after drops were instilled and visual field tests were performed at baseline and at the end of each crossover period. Significantly more patients receiving pilocarpine than dorzolamide reported adverse experiences and discontinued the drug because of these adverse experiences. Similarly, patients reported more interference with their daily life because of side effects and activity limitations when receiving pilocarpine. Vision difficulties, accommodation difficulties, and brow ache were reported more often and were considered more bothersome by patients receiving pilocarpine. Bitter/unusual taste was reported more frequently and was considered more bothersome by patients receiving dorzolamide. Patients also reported missing fewer doses and were more satisfied with their medication when receiving dorzolamide. All of these changes were considered statistically significant. IOP control was not significantly different with either dorzolamide or pilocarpine. However, patients experienced a significant worsening of the mean defect of automated visual field examinations when receiving pilocarpine. At the end of the study, among patients with a preference, dorzolamide was preferred to pilocarpine by a ratio of more than 9:1. Overall, 81.9% of patients preferred dorzolamide. Thus dorzolamide demonstrated better tolerability and less adverse impact on daily life than pilocarpine.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Cost-effectiveness analysis of entacapone in Parkinson's disease: a Markov process analysis.

OBJECTIVE: The objective of this study was to examine the cost-effectiveness of a complementary treatment with entacapone versus usual care only in patients with Parkinson's disease. METHODS: The setting for this study was the Netherlands. A Markov process model was constructed to model the average quality-adjusted life years (QALYs) and the costs of both treatments. The model examined a period of 5 years in order to capture the influence of symptom improvement and disease progression. Data for the construction of the model were derived from published literature, including large, multicenter, randomized clinical trials in patients with end-of-dose motor fluctuations. Costs were obtained from published sources. RESULTS: The results of the baseline analysis showed that the use of entacapone as complementary therapy in Parkinson's disease slightly decreased the total average discounted costs from NLG 111,317 to NLG 110,038, while effectiveness increased from 2.42 to 2.56 QALYs (a 6% increase). In addition, entacapone substantially increased time without severe fluctuations by 0.63 years. Sensitivity analyses confirmed the robustness of these findings. CONCLUSION: The study shows that entacapone is a cost-effective treatment in patients with Parkinson's disease: entacapone yields higher effectiveness in terms of both effectiveness measures (time without severe fluctuations and QALYs), while costs remain quite similar to those for usual care. The additional drug costs for entacapone are offset by reductions in other costs.

Aged↗
PubMedDate not supplied

Administration of microaggregate filtered blood using a manual infusion pump.

Administration sets containing in-line plastic blood pumps are commonly used to transfuse blood. Flow rates were measured while six units of whole blood and red blood cells were infused through a blood pump administration set coupled to either a large pore 260-micron filter or a 20-micron microaggregate blood filter. Using the same type of blood pump administration system and three units of whole blood, the flow rates achieved by the currently available microaggregate blood filters were compared. Results showed that despite a smaller pore size the 20-micron microaggregate blood filter achieved flow rates that were faster than or equal to those recorded for the larger pore (260-micron) filter. This was attributed to the larger filtration surface area possessed by the smaller pore filter, 140 cm2 versus only 30 cm2 for the 260-micron filter. All of the microaggregate filters studied were able to filter three units of whole blood at flow rates in excess of 80 ml/minute. There was no evidence of blood pump induced hemolysis. We concluded that a manual infusion pump can be used to transfuse microaggregate filtered blood rapidly enough to be acceptable for routine clinical or intraoperative use.

Blood Flow Velocity↗
PubMedDate not supplied

Plasma separation using a hollow fiber membrane device.

A disposable hollow fiber device was evaluated by collecting approximately 550 ml of normal donor plasma (n = 43) and by performing sham (n = 10) and therapeutic (n = 12) plasma exchanges. Blood was processed at 70 ml per min, and plasma flux averaged 23 (collection) and 25 (exchange) ml per min (mean separation efficiencies of 52 and 60%, respectively). The procedures were tolerated well by all donors and patients. The plasma hemoglobin concentration in separated plasma averaged 1 mg per dl, and cell contamination was negligible (mean of 1, 3, and 6 RBCs, platelets and WBCs/microliter, respectively). There was no evidence of in vivo classical or alternative pathway complement activation as assessed by total hemolytic complement generation (CH50), alternative pathway hemolytic activity (AP50), C3 conversion, or C5 activation, nor were unexpected changes seen in the results of laboratory tests performed after the procedure. Sieving coefficients during sham plasma exchange averaged as follows: albumin, 1.03; IgM, 1.0, IgG, 1.0; IgA, 0.98; factor V, 1.07; factor VII, 0.89; factor VIII, 1.05; and factor IX, 1.19. The device appears to be useful for separation of cell-free plasma from blood during therapeutic plasma exchange procedures.

Blood Component Removal↗
PubMedDate not supplied

The relative effects of health and income on life satisfaction.

The relative effects of health and income on life satisfaction were analyzed using data collected in three recent national surveys. Financial situation was a slightly stronger predictor of life satisfaction for persons under age sixty-five, whereas health condition had a stronger impact on the life satisfaction of persons over age sixty-four. An attempt was made to quantify the relative impact of health and income on life satisfaction through an analysis of conjoint influence with contingency tables.

Adult↗
PubMedDate not supplied

Test your troubleshooting knowledge.

While troubleshooting and repairing medical instrumentation may be all that BMETs would like to do, it's just too limited in scope to perform the job effectively. Flattened organizations can require greater responsibility for BMETs--and lead to greater ambiguity. Besides electronic troubleshooting skills, mechanical ability, and the knowledge of how medical equipment normally operates, additional skills are required of the BMET to effectively facilitate a repair--such as knowledge of pertinent codes and standards, job safety laws and guidelines, politeness, and empathy for the equipment user. You will notice that many of these relate to interpersonal relations. The ability to interact with fellow health care workers in a non-threatening manner and to have an appreciation for their perspectives are valuable customer service skills--potentially more valuable than being able to do component-level troubleshooting!

Biomedical Engineering↗