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Biomedical subjects

E Ackerman

Publications and source records attributed to E Ackerman.

16 recordsLinked to original sources
PubMed1992

Iontophoretic delivery of morphine for postoperative analgesia.

Iontophoresis is a method of transdermal administration of ionized drugs in which electrically charged molecules are propelled through the skin by an external electrical field. This was a prospective, randomized, single-blind study to determine the effectiveness of iontophoretically delivered morphine HCl for the control of postoperative pain. Thirty-eight patients who underwent total knee or hip replacement completed this clinical trial. Informed consent was obtained before surgery and patients were instructed on the use of a patient-controlled analgesia (PCA) device. Postoperatively, pain in the recovery room was initially controlled with IV meperidine, and thereafter with PCA therapy using meperidine, 2 mg/cc, with a dose of 10 mg IV and a lock-out period of 15 min. The dose was adjusted as necessary and the lock-out period remained the same. The number of patient requests and the dose (mg) administered was recorded hourly. On the morning following surgery, iontophoresis devices were attached for 6 hr to patients who received either morphine HCl or lactated ringers solution. During this period and for 12 hr following completion of iontophoresis, PCA analgesia remained available to patients. Venous blood samples for determination of morphine levels were obtained every 30 min during iontophoresis, then every 60 min for 2 hr following iontophoresis. Of the 38 patients, 17 received iontophoresed morphine, and 21 received iontophoresed lactated ringers. The morphine group utilized the PCA device more than the control group during the baseline period. However, following the institution of iontophoresis and continuing up to 12 hr following completion of iontophoresis, the morphine group used significantly less PCA meperidine to maintain analgesia than the control group (p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Pancreatitis induced by mesalamine.

Sulphasalazine is an active agent in the treatment of chronic inflammatory bowel disease, but there are a number of well-known side effects, including pancreatitis. The newer 5-ASA agents are thought to be equally effective but less toxic. Here we describe a patient who developed a pancreatitis due to mesalamine; this was confirmed at rechallenge.

Acute Disease↗
PubMed1991

Polychotomous multivariate models for coronary heart disease simulation. I. Tests of a logistic model.

Stochastic compartmental modeling techniques have been employed to simulate coronary heart disease morbidity and mortality. In the current paper, polychotomous logistic models are used to describe the relationship between risk of disease and multiple risk factors, effect modification and confounding variables. The process of estimating the parameters for two risk factors and three types of outcomes is described for a population followed for five years. A Statistical Analysis System (SAS) procedure was used to estimate risk factor coefficients based on two partial periods and on the entire five year epoch. Most of the estimated coefficients were found to be statistically significant. The model performance was evaluated by comparing the observational data with simulated outcomes using a micropopulation and Monte Carlo techniques. Two different tests of goodness of fit were used. Satisfactory fits were obtained both for the risk coefficients based on two partial periods and those based on the entire epoch. This indicates that the model is suitable for simulation of the effects of intervention strategies. The use of the entire epoch involved estimates of one half as many parameters as did the use of two partial periods. Accordingly, it is concluded that only the entire epoch need be considered for future studies of this population.

Adult↗
PubMed1991

An expert system for simulation of coronary heart disease risk factor interventions.

The feasibility of using an expert system to support intervention studies within CRISPERS was investigated. A prototype expert system named CRISPERT was designed to accept user inputs, adjust the values to CRISPERS requirements, start a sequence of simulations, and analyze and interpret the results. The rule-based system was implemented using the expert system development language OPS5 combined with FORTRAN, as well as SAS procedures and DEC VMS system service routines. Results of initial tests suggest that using an expert system as an interface between users and CRISPERS is a viable approach. The development of CRISPERT facilitates the usability of CRISPERS for intervention studies of coronary heart disease.

Computer Simulation↗
PubMed1990

Cardiovascular effects of large doses of pentamorphone in the dog.

The cardiovascular effects of large doses of pentamorphone were evaluated in nine mongrel dogs basally anesthetized with sodium thiopental, 25 to 30 mg/kg, intravenously. All dogs were mechanically ventilated with 100% oxygen, and the PaCO2 was maintained between 35 and 40 mm Hg. Mean arterial pressure (MAP), central venous pressure, heart rate (HR), cardiac output (CO), pulmonary artery pressure, and pulmonary artery occluded pressure were measured, and stroke volume and systemic and pulmonary vascular resistances were calculated. Baseline measurements were obtained, then pentamorphone, 10 micrograms/mL, was given as an intravenous infusion at 2.5 micrograms/kg/min. Additional data were obtained after infusion of 25, 50, 75, 100, 125, 150, 200, 250, 300, and 350 micrograms/kg of pentamorphone. The inspired gases were then changed to 50% nitrous oxide in oxygen, and after a 20-minute equilibration period, an additional set of data was collected. Pentamorphone, 25 micrograms/kg, decreased HR 50%, MAP 65%, and CO 54%. No further changes in any measured or calculated variables were observed with additional doses of pentamorphone. The addition of 50% nitrous oxide to the inspired gas mixture had no effect on any measured or calculated hemodynamic variable. The minimal hemodynamic effects of pentamorphone in the dog suggest that further investigation into its use as an anesthetic is warranted.

Analysis of Variance↗
PubMed1979

Immunonephelometric assays.

Nephelometry, the measurement of scattered light, determines the size, shape, and concentration of the scattering particles (at least in theory). For the applications of nephelometry in immunoassays, the scatterers are the antigen-antibody complexes formed. The rationale for using nephelometry includes the advantages of greater simplicity and improved precision as compared to other assay methods. There are, however, other factors which limit the immunological assays in which nephelometry is employed, most notably its sensitivity to noise due to dust and occasional large aggregates of antigen-antibody complexes. Nephelometers commercially available for immunoassays use a variety of light sources; most measure the scattered light at a single angle, and several incorporate microcomputers. A review of the theory of light scattering by small spheres is introduced to indicate fashions in which future developments may make nephelometry the method of choice for an even wider range of immunoassays.

Humans↗
PubMed1978

Investigation of statistical decision rules for sequential hematologic laboratory tests.

A statistical data processing program for identifying patients who are likely to have abnormalities on various hematologic laboratory tests is described. The prediction of abnormal levels of serum vitamin B12, serum folate, transferrin saturation, and reticulocyte counts is based on a statistical analysis of the patient's age, sex, and routine blood cell measurements. The program was developed using data from normal-value studies and data from patients who had these laboratory abnormalities. The sensitivity and specificity of the program were evaluated in a controlled prospective study of about 5,000 ambulatory adult patients. The program's predictions also were compared with the laboratory tests requested by the patients' attending physicians. The program was most sensitive for predicting low serum vitamin B12 (74%) and low transferrin saturation (78%). In the prospective evaluation, the predictive values varied from 11% for predicting low serum folate to 65% for predicting low transferrin saturation.

Adult↗
PubMed1978

Relative merits of two electrophoretic and two column-chromatographic kets for determining serum creatine kinase isoenzyme MB activity.

Prospective analysis (by use of commercially available kits) of 339 validated admission specimens from patients consecutively admitted to a cardiac monitoring unit revealed sensitivities of 68 and 63% for two electrophoretic assays (Bioware and Helena) and up to 73 and 77% for two chromatographic assays (Roche and Worthington). Specificities were 94.8, 96,6, 90.2, and 89.7% and efficiencies were 90.2, 90.7, 87.0, and 87.0, respectively. Although these results differ from early reports, they agree well with several recent studies. However, 86 (25%) of the specimens gave at least one discrepant result based on clinical evaluation of the patients, and 68 (20%) gave at least one discrepant result between methods.

Chromatography, Ion Exchange↗
PubMed1977

Economic impact of a computer-based centralized organization in a clinical laboratory.

The Department of Laboratory Medicine, University of Washington, has explored various management of organizational approaches over the past seven years. The Centralized Processing Area supported by a computerized information system has evolved from these efforts. Despite a decrease in U.W. hospital usage since 1968-69, laboratory volume has steadily increased. The cost of these services is shown in relation both to three successive management systems and to the impact of inflation on laboratory costs. Chemistry and hematology costs per procedure, including administration and computer costs, are compared with microbiology cost per procedure, where the management system was not used. There is growing acceptance of the intangible benefits of computerization in the laboratory. Economic benefits are often presumed but have not been proven. Favorable economic effects of the Centralized Processing Area together with the computerized information system are demonstrated.

Autoanalysis↗
PubMed1976

An influenza simulation model for immunization studies.

A stochastic simulation epidemic model based on discrete time intervals and appropriate for any infectious agent spread by person-to-person contacts is presented. The population is highly structured, allowing for five age groups and for subgrouping mixing in families, neighborhoods, schools, and preschool playgroups as well as total community mixing. With proper choice of relative susceptibility by age, length of latency and infectivity periods, pathogenicity and withdrawal patterns, and the relative infectiousness of silent infections, the model becomes highly agent-specific. The model includes flexible immunization routines and variable vaccine response patterns. The model is applied to the 1957 Asian and 1968 Hong Kong pandemic strains of influenza A. The results of several schedules of immunization of school children are presented and compared for the two strains.

Adolescent↗
PubMedDate not supplied

Polychotomous multivariate models for coronary heart disease simulation. II. Comparisons of risk functions.

This is the second in a series of papers dealing with models of coronary heart disease. Three different types of statistical models are considered as risk functions: the multivariate logistic model, the Cox proportional hazard model and the Neyman exponential risk avoidance model. The types of models differ in the form hypothesized for the probability of occurrence of coronary heart disease outcomes: incident myocardial infarct, cardiac death, and death from other causes. Although the three risk functions are strikingly different, they can all be tested using the CRISPERS chronic disease simulation system. Simulations were performed using data from North Karelia, Finland. The polychotomous multivariate logistic risk function is convenient for studies involving increasing numbers of risk factors. The Cox proportional hazard regression model is shown to be unsuitable for the cohort dataset used as well as for some of the intended uses of the simulation models. The Neyman exponential risk avoidance model involves time in a quite different fashion. It has the inherent advantage of being easier to relate to underlying biological mechanisms because it is the integral of first order rate equations. It is concluded that more than one risk function should be evaluated for simulations of coronary heart disease.

Adult↗
PubMedDate not supplied

Polychotomous multivariate models for coronary heart disease simulation. III. Model sensitivities and risk factor interventions.

This is the third in a series of papers dealing with models of coronary heart disease. Sensitivity analyses of the logistic risk function and the Neyman risk function are reported. The resulting response surfaces are also used to investigate the optimality of the set of values for the risk coefficients. It is shown that the coefficients estimated by maximum likelihood are preferable to the sets from an optimisation procedure. Two different sets of risk coefficients estimated using short periods and entire epochs for the logistic risk function are shown to lead to similar conclusions concerning simulated primary intervention strategies. However, the corresponding risk factor reductions using the Neyman risk function lead to somewhat different effects. Additional information is needed to distinguish between these two assumptions of the risk function used to model coronary heart disease. This underscores the need to understand the effects of the underlying risk function assumed when interpreting simulated outcomes of intervention strategies.

Computer Simulation↗