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E Ackerman

Publications and source records attributed to E Ackerman.

At least 19 recordsLinked to original sources
PubMed2000

[Does incidence of hepatitis A increase during shmitah (the Sabbatical year)?].

In Israel the biblical injunction of the sabbatical year (shmitah) prevails, whereby all Jewish-owned land should lie fallow during every seventh year. Consequently, it is customary for members of the orthodox Jewish community to eat only produce grown by non-Jews (Arabs). Many Arab farmers use sewage water for irrigation and since such water could be infected with hepatitis A virus (HAV), there is concern about the possibility of HAV epidemics during the sabbatical year. We therefore we examined the data of the Israeli Center for Disease Control (ICDC). We found no obvious increase in incidence of viral hepatitis during, nor in the year immediately after, all sabbatical years since 1951. However, the data was not comprehensive as it included only partial information on morbidity from HAV in our Jewish inhabitants. Also, there was no data specific for the orthodox Jewish community, which is especially at risk for HAV from sewage-irrigated vegetables. Irrespective of shmitah, there should be constant effort to prevent HAV infection in Israel.

Agriculture↗
PubMed2000

Diffusion of n-butyl-p-aminobenzoate (BAB), lidocaine and bupivacaine through the human dura-arachnoid mater in vitro.

INTRODUCTION: Epidural administration of a suspension of n-butyl-p-aminobenzoate (BAB) to humans resulted in a selective, ultra-long lasting sensory block without motor function impairment. The absence of motor block was attributed to 'spatial' confinement of active concentrations of dissolved BAB within the epidural space. This study was designed to investigate the diffusion of BAB through the human dura-arachnoid membrane in vitro relative to lidocaine and bupivacaine and to quantify the influence of the composition of the suspension formulation on this flux. MATERIALS AND METHODS: Human dura-arachnoid specimens were mounted between the donor and the receiver compartment of a diffusion cell. Five concentrations of BAB, lidocaine and bupivacaine in phosphate-buffered saline, pH 7.4, were added to the donor compartment and the increase of the concentration of the agent in time in the receiver compartment was measured by automated UV-spectrometry. Fluxes and permeabilities were calculated. The influence of pH, polysorbate 80 (PS 80) and polyethylene glycol 3350 (PEG 3350) on the flux of BAB in solution and in suspension formulations were analyzed. RESULTS: The flux of both lidocaine and bupivacaine at pH 4 was considerably smaller than at pH 7.4. Permeabilities decreased in the order bupivacaine>lidocaine&z.Gt;BAB and at the level T12>T1. PS 80 at concentrations exceeding 0.025 mg/ml and PEG 3350 decreased the flux of BAB from BAB-solutions. Used in the preparation of the suspension, PS 80 and PEG 3350 did significantly reduce the permeability. DISCUSSION: The results of this study are consistent with the hypothesis that the selective action of epidurally applied BAB suspension can be attributed to the spatial confinement of active BAB-concentrations within the epidural space. Additives used in the preparation of the aqueous suspension formulation may substantially influence the local pharmacokinetics and by that the pharmacodynamic effects.

Anesthetics, Local↗
PubMed2000

Intrafamilial transmission of hepatitis C virus: a systematic review.

To examine the risk of hepatitis C virus (HCV) transmission between patients infected with HCV and their household members (siblings, offspring and parents), as well as their stable heterosexual partners, a systematic search of the MEDLINE database was undertaken for all relevant articles published up to June 1997. English language publications or those supplemented with an English abstract that reported studies concerning hepatitis C, and household, intrafamilial, sexual and intraspousal transmission of HCV, were reviewed. Data from uncontrolled and controlled studies were collected and analysed separately. Studies reporting the exclusive use of first-generation anti-HCV antibodies without supplemental tests were excluded. Pre- or postnatal mother-to-child transmission of HCV and homosexual and heterosexual transmission of HCV among non-permanent couples were not included. Unweighted data from individual studies were pooled for each category of family member. Data were also analysed separately for Japanese and non-Japanese studies because there is evidence that intrafamilial transmission may differ, based on endemicity of the viral infection. Comparisons were drawn only from controlled studies that reported the prevalence of HCV in family members of both HCV-positive and HCV-negative controls. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated for each family category. In uncontrolled studies, the pooled prevalence of anti-HCV among 4250 stable sexual contacts of patients with HCV-related chronic liver disease (CLD) was 13.48%, while the pooled prevalence of anti-HCV among 580 stable sexual contacts of patients who contracted HCV as a result of multiple transfusions was 2.41%. In controlled studies, the pooled prevalence of anti-HCV among 175 siblings and household contacts of patients with CLD was 4.0% compared with 0% among 109 contacts of anti-HCV-negative controls (OR 9.75, 95% CI 0.91 ad infinitum). The pooled prevalence of anti-HCV among offspring of Japanese HCV-infected CLD patients was 17% compared with 10.4% among offspring of HCV-negative Japanese controls (OR 1.77, 95% CI 1.21-2. 58, P=0.002). The pooled prevalence of anti-HCV among spouses of non-Japanese HCV-infected CLD patients was 15.2% compared with 0.9% in the spouses of non-Japanese HCV-negative controls (OR 20.57, 95% CI 6.05-84.08, P=0.0001). The prevalence of anti-HCV among non-Japanese offspring and Japanese spouses of HCV-infected patients was not increased compared with controls. HCV genotype homology and mutant analysis studies in pairs of HCV-infected patients and their HCV-infected contacts showed that concordant genotype homology was found in 66% of non-sexual contacts and in 74% of sexual contacts. Sequence homology of greater than 92% was found in 19 out of 35 pairs. Hence, evidence exists that familial, non-sexual and sexual transmission of HCV does occur. In Japanese patients, transmission probably occurs in younger family members while, in non-Japanese patients, transmission probably occurs at an older age, after contact with an HCV-infected spouse.

Disease Transmission, Infectious↗
PubMed1998

Preliminary evidence for aberrant cortical development in abused children: a quantitative EEG study.

The objectives of this study were to investigate cortical development and hemispheric asymmetry in abused children. Fifteen hospitalized children (mean age 10.7 +/- 2.5 years) with severe physical or sexual abuse and 15 normal children (10.1 +/- 3.1 years) were studied with quantitative EEG. Abused children had higher levels of left hemisphere coherence and a reversed asymmetry, with left hemisphere coherence significantly exceeding right hemisphere coherence. Left hemisphere coherence decreased more rapidly across electrode distance in normal subjects, suggesting that increased left coherence in abused patients stemmed from a deficit in left cortical differentiation. These findings support the hypothesis that early severe abuse may have a deleterious effect on brain development.

Adolescent↗
PubMed1995

Simulation of micropopulations in epidemiology: tutorial. 4. Evaluations of simulation models. A series of tutorials illustrated by coronary heart disease models.

The first tutorial in this series (Ackerman E: Simulation of micropopulations in epidemiology: Tutorial 1. Simulation: an introduction, Int J Biomed Comput, 36 (1994) 229-238) introduces the general approach of simulation of micropopulation models of coronary disease using Monte Carlo techniques. The modeling process includes the selection of functional forms to represent the probability of state transfers. Alternative functional forms are described in the second tutorial (Ackerman E: Simulation of micropopulations in epidemiology: Tutorial 2. Analytic forms of event probabilities, Int J Biomed Comput, 37 (1994) 139-149). The third tutorial (Ackerman E: Simulation of micropopulations in epidemiology: Tutorial 3. Simulation model evaluation methods, Int J Biomed Comput, 37 (1994) 195-204) considers the actual risk factors used in the models and the compartmentalization of the population. However, that tutorial emphasizes the methods of evaluating different models of coronary heart disease. In the current tutorial, the evaluation methods are applied to the models previously introduced. Essential to this is the concept of degrees of freedom. Limitations of that concept are discussed with specific reference to models of coronary heart disease. The estimation of optimal values for the risk coefficients is considered further. The various tests of appropriateness are applied to specific models and the role of sensitivity analysis is further illustrated. Discussions of intervention strategies and their simulation is deferred to the following tutorial.

Adult↗
PubMed1994

Simulation of micropopulations in epidemiology: tutorial 1. Simulation: an introduction. A series of tutorials illustrated by coronary heart disease models.

This is the first in a series of tutorials concerning the simulation of micropopulation models for use in epidemiological research. The series emphasizes the techniques that are in use at the National Micropopulation Simulation Resource at the University of Minnesota. This initial series of tutorials uses chronic disease models, specifically coronary heart disease models, to illustrate the principles and methodologies employed. The series is intended for persons having some familiarity with electronic, digital computation and desiring to know more about a specific class of simulations, namely those that apply Monte Carlo techniques in the simulation of micropopulation models as a part of biomedical research. It is the author's hope that these tutorials will be particularly useful for students in medical informatics; they could also be of interest to professionals in both the computational and the biomedical sciences.

Chronic Disease↗
PubMed1994

Simulation of micropopulations in epidemiology: tutorial 2. Analytic forms of event probabilities. A series of tutorials illustrated by coronary heart disease models.

This is the second in a series of tutorials concerning the simulation of micropopulation models to support epidemiological research. The series emphasizes techniques that are included in studies at the National Micropopulation Simulation Resource at the University of Minnesota. For pedagogic purposes, applications to coronary heart disease models are used to illustrate the principles and methodologies employed. All of the models presented are implemented using available software. Both interpretation of the results of survey and surveillance data, and the simulation for predictive purposes of micropopulation models, depend upon the form chosen to represent the probability of the occurrence of an event associated with coronary heart disease. Four different forms are discussed; each can be used to represent the probability of transfer from the healthy state to one of the disease states or, in other words, the probability of occurrence of an event of interest. These four forms are by no means all-inclusive; rather they are ones that are convenient to use with micropopulation simulation models and that exhibit a variety of the different possibilities.

Computer Simulation↗
PubMed1993

Simulation of stochastic micropopulation models--I. The SUMMERS simulation shell.

A generic, abstract model and the simulation shell based on it, both called SUMMERS, are used as a framework for the implementation of stochastic micropopulation models; in these, each individual is followed separately while moving through a sequence of states. The shell supports groups of interacting members, individual characteristics and multiple simultaneous activities. Stochastic decisions may be made using Monte Carlo rules. Keywords control the simulations and the reports generated. A sensitivity analysis utility allows assessment of the dependency of outcomes on model features. Extensive use has been made of software engineering techniques. Specializations of SUMMERS are described in subsequent papers.

Data Collection↗
PubMed1993

Simulation of stochastic micropopulation models--II. VESPERS: epidemiological model implementations for spread of viral infections.

This second paper concerning stochastic micropopulation simulations describes VESPERS, which can serve as a framework for simulation models of the epidemic spread of infection. The versions described are implemented using the simulation shell, SUMMERS, which includes the generic commonalities of several micropopulation models. Population members in VESPERS move through states related to the individual's status relative to the infective agent. Features of the models include mixing groups, member demographics, susceptibility and infectiousness, and co-circulation of infectious agents. The sensitivity of the simulation outcomes to quantitative features of the model has been analyzed. The user can select reports of desired distributions and averages of simulation outcomes.

Demography↗
PubMed1993

Simulation of stochastic micropopulation models--III. COGNET: an artificial neural network for visual recognition.

COGNET, based on a neural network first described by Fukushima, demonstrates the relationship between connectionist and other micropopulation models. Its success and physiological orientation led to an implementation using the SUMMERS simulation shell. After self-supervised learning, COGNET uses forward and backward propagation of signals to recognize partial and noisy patterns, and to reconstruct the originals. Stochastic features include variable thresholds for neuronal firing and occasional cell death. The successful implementation of COGNET demonstrates the generality of the concepts embodied in SUMMERS, which in turn promotes the reusability of software and facilitates the extension of computational models in biomedical research. COGNET itself forms a framework for building other physiologically oriented neural network models.

Computer Simulation↗
PubMed1993

Parameter sensitivity of a model of viral epidemics simulated with Monte Carlo techniques. I. Illness attack rates.

This is the first of a series of papers concerning sensitivity analyses of stochastic micropopulation models. A model of epidemic spread of viral infection is used in this series to illustrate the principles and performance of the sensitivity analysis system. For these studies the analysis system now known as SENSEN was redesigned and extended to use the principles and modules of the SUMMERS simulation shell. The latter was used in the implementation of the epidemic model as well as a number of others. The SENSEN system can be used with any of these. The advantages of sensitivity analysis for stochastic micropopulation models are discussed. Its general form and operation are illustrated by a comparison of illness attack rates with infection attack rates.

Adult↗
PubMed1993

Parameter sensitivity of a model of viral epidemics simulated with Monte Carlo techniques. II. Durations and peaks.

This is the second of a series of papers concerning sensitivity analyses of stochastic micropopulation models. A model of epidemic spread of viral infection is used in the series to illustrate the principles and performance of the sensitivity analysis system. For these studies the analysis system now known as SENSEN was redesigned; it can be used with any specialization of the SUMMERS simulation shell. Previous applications of SENSEN and its predecessors studied the sensitivity simultaneously to at most six input parameters. The applicability of SENSEN when twelve input parameters are selected is illustrated by sensitivity analyses of epidemic durations. A time-related output, day of the epidemic at which the peak number of cases are present, is also studied.

Adult↗
PubMed1993

Parameter sensitivity of a model of viral epidemics simulated with Monte Carlo techniques. III. Optimization strategies.

The output of the sensitivity analysis system, SENSEN, described in the preceding two papers is applied to an optimization study for the VESPERS model of the spread of infection with influenza virus in a community. We know of no similar studies. In this application, constrained, non-linear optimization routines in IMSL are used. The optimization study attempts to answer whether behavioural modification (modeled as discrete interventions) is necessary to represent simultaneously the age-specific attack rates and the epidemic curve. The results presented here indicate that such model interventions are necessary.

Adolescent↗