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PubMed1995

Multisite experimental cost study of intensive psychiatric community care.

A 2-year experimental cost study of 10 Intensive Psychiatric Community Care (IPCC) programs was conducted at Department of Veterans Affairs (VA) medical centers in the Northeast. High hospital users were randomly assigned to either IPCC (n = 454) or standard VA care (n = 419) at four neuropsychiatric (NP) and six general medical and surgical (GMS) hospitals. National computerized data were used to track all VA health care service usage and costs for 2 years following program entry. At 9 of the 10 sites, IPCC treatment resulted in reduced inpatient service usage. Overall, for IPCC patients compared with control patients, average inpatient usage was 89 days (33%) less while average cost per patient (for IPCC inpatient, and outpatient services) was $15,556 (20%) less. Additionally, costs for IPCC patients compared with control patients were $33,295 (29%) less at NP sites but were $6,273 (15%) greater at GMS sites. At both NP and GMS sites, costs were lower for IPCC patients in two subgroups: veterans over age 45 and veterans with high levels of inpatient service use before program entry. No interaction was noted between the impact of IPCC on costs and other clinical or sociodemographic characteristics. Similarly, no linear relationship was observed between the intensity of IPCC services and the impact of IPCC on VA costs, although the two sites that did not fully implement the IPCC program had the poorest results. With these sites excluded, the total cost of care for IPCC patients at GMS sites was $579 (3%) more per year than that for the control patients.

Activities of Daily Living↗
PubMedDate not supplied

Cardiac phase: amplitude analysis using macro programming.

The analysis of EKG gated radionuclide cardiac imaging data with Fourier amplitude and phase images is becoming a valuable clinical technique, demonstrating location, size, and severity of regional ventricular abnormalities. Not all commercially available nuclear medicine computer systems offer software for phase and amplitude analysis; however, many systems do have the capability of linear image arithmetic using simple macro commands which can easily by sequenced into stored macro-strings or programs. Using simple but accurate series approximations for the Fourier operations, macro programs have been written for a Digital Equipment Corporation Gamma-11 system to obtain phase and amplitude images from routine gated cardiac studies. In addition, dynamic cine-mode presentation of the onset of mechanical systole is generated from the phase data, using only a second set of macro programs. This approach is easily adapted to different data acquisition protocols, and can be used on any system with macro commands for image arithmetic.

Computers↗
PubMedDate not supplied

A method to measure the impact of primary care programs targeted to reduce racial and ethnic disparities in health outcomes.

A retrospective population-based study was designed to test the impact on selected health outcomes of community-based primary care programs targeting racial and ethnic minorities. Zip codes were coded as either "high" or "low" access to targeted primary care programs to create the independent variable of interest. Outcome measures were chosen to represent unique dimensions of primary care. Generalized linear models were developed to compare rates for the outcome measures among blacks in high- and low-access areas. This study provides a useful approach that could be used to evaluate the impact of such programs in other communities.

Black or African American↗
PubMed2005

Predictability and prediction of lowest observed adverse effect levels in a structurally heterogeneous set of chemicals.

A database of chronic lowest observed adverse effect levels (LOAELs) for 234 compounds, previously compiled from different sources (Toxicology Letters79, 131-143 (1995)), was modelled using graph theoretical descriptors. This study reveals that data are not homogeneous. Only those data originating from the U.S. Environmental Protection Agency (EPA) reports could be well modelled by multilinear regression (MLR) and linear discriminant analysis (LDA). In contrast, data available from the specific procedures of the National Toxicology Program (NTP) database introduced noise and did not render good models either alone, or in combination with the EPA data.

Animals↗
PubMed2001

Symmetry and linearity of trunk function in subjects with non-specific low back pain.

Objective. To investigate the effect of a standard rehabilitation program on the symmetry of trunk kinematics in subjects with non-specific low back pain.Design. Assessing lumbar spine kinematics in the cardinal planes using dynamometry.Background. Previous evaluations of trunk symmetry focussed more on anatomical rather than functional symmetry. Correlation of functional symmetry with low back pain was occasionally performed, but only for base line evaluations. To the best of the author's knowledge, there is no study examining the effect of exercise on the functional symmetry of the trunk, especially in non-specific low back pain subjects.Methods. Two groups of young male subjects whose working conditions incurred long daily hours of sitting and standing participated in the study. Muscles of the lumbar spine were initially evaluated in the cardinal planes using dynamometry. The same parameters (maximum isometric torque, dynamic torque, angular velocity and range of motion) were then repeatedly measured throughout a standardized strength protocol lasting for 12 sessions over a four-week period.Results. As pain gradually disappeared over a one-month period of rehabilitation, certain factors of the trunk kinematics exhibited convergence towards perfect symmetry while others showed oscillations. Moreover, global right-left data for certain trunk kinematics exhibited near-perfect linear relationship.Conclusion. Functional symmetry of the trunk in the coronal and transverse planes can be used to assess the progress of rehabilitation programs of non-specific low back pain subjects. RelevanceRehabilitation programs focus on the progress of directly measured trunk kinematics, which do not always exhibit monotonic behavior. This paper alludes to the importance of tracking symmetry of trunk kinematics as it may help clinicians modify the strengthening protocols in order to achieve more rapid relief from back pain.

Adult↗
PubMedDate not supplied

[Use of a multileaf collimator for the production of intensity-modulated beams].

In external radiotherapy, the use of intensity modulated fields has been proposed for tissue and non-homogeneity compensation or for the generation of conformal dose distributions. Multileaf collimators can be employed dynamically for the modulation of the X-ray field in two dimensions. Efficient dynamic collimation became possible due to advances in computer and linear accelerator technology. It presents a number of advantages over conventional methods such as the use of compensators. We have developed a program which calculates, from a given intensity distribution, the motion of the MLC leaves as a function of monitor units, and we have applied it on a Varian linear accelerator with a 40 pair multileaf collimator. The analysis of the experimental results demonstrates the feasibility and the potential of the method.

Algorithms↗
PubMed2005

What predicts USMLE Step 3 performance?

BACKGROUND: Academic and other student-specific variables associated with United States Medical Licensing Examination (USMLE) Step 3 performance have not been fully defined. METHOD: We analyzed Step 3 scores in association with medical school academic-performance measures, gender, residency specialty, and first postgraduate year (PGY-l) of training program-director performance evaluations. RESULTS: There were significant first-order associations between Step 3 scores and each of USMLE Step 1 and Step 2 scores, third-year clerkships' grade point average (GPA), Alpha Omega Alpha election, Medical Scientist Training Program graduation, broad-based specialty residency training, and PGY-l performance evaluation score. In a multiple linear regression model accounting for over 50% of the total variance in Step 3 scores, Step 2 scores, broad-based-specialty residency training, and GPA independently predicted Step 3 scores. CONCLUSIONS: Individualized Step 3 scores provide medical schools with additional means to externally validate their educational programs and to enhance the scope of outcomes assessments for their graduates.

Clinical Clerkship↗
PubMed1991

Computerized approach to monitoring aminoglycosides.

Aminoglycosides are still used extensively in the treatment of nosocomial infections with Gram-negative bacteria. However, the treatment is associated with several adverse effects. Aminoglycosides monitoring is therefore essential to prevent toxic accumulations and to reach therapeutic concentrations. A computer program, PHARMONITOR, has been developed to optimize aminoglycosides monitoring, responding to the demands of most clinical daily situations. This program, based on a one-compartment open pharmacokinetics model, is developed for IBM PC-compatible computers, using D-Base III+. It can calculate t1/2, Vd, Cldrug, Cpmax, and the theoretical optimal dose and interval and also evaluates the creatinine clearance. The program has been conceived to allow maximal speed, flexibility, and reliability by the use of (e.g.) a linear least-squares analysis, the possible reference to previous protocols, the extensive use of keywords to classify and recall patients according to their pathologies, the development of messages recommending maximal dose or minimal dosing interval, and increasing the safety of the analysis. We consider the program a valuable tool for adjusting aminoglycoside dosage in individuals.

Aminoglycosides↗
PubMed2000

Granularity of the carotid artery intima-medial layer: reproducibility of quantification by a computer-based program.

Ultrasound of the carotid artery identifies the hypoechoic intima-medial layer (IML). Increased granularity of the IML has been associated with early atherosclerosis. The aim of the study was to assess the reproducibility and observer agreement of a computer-based program measure of IML granularity. Ten healthy adult volunteers (median age 32 years, range 18-34 years) were examined twice, 2 weeks apart, with a 7 MHz linear transducer using standardized imaging settings, by two observers. Images of both common carotid arteries were digitized and analysed on a customized computer program. The ratio (averaged over a 1 cm length of arterial wall) of the lowest pixel brightness in the IML to the maximum pixel brightness in the intima-medial interface was determined. Overall mean intima-medial reflectivity (IMR) indices for the two observers were 0.761 +/- 0.101 and 0.707 +/- 0.103, with single determination standard deviation values of 0.090 and 0.073, respectively. For interobserver calculations, the overall mean IMR index for both sessions was 0.734 +/- 0.107, with a single determination standard deviation of 0.067. Comparison with the intima-medial thickness (IMT) showed an inverse correlation (r = -0.72). This method of quantifying the reflectivity of the IML demonstrates good reproducibility in subjects with normal IMT measurements. The technique may be of value in identifying subjects at high risk of atherosclerosis but with IMT still within the normal range.

Adolescent↗
PubMed1977

A comprehensive radiotherapy planning system implemented in Fortran on a small interactive computer.

A suite of Fortran programs for carrying out the various dose computational aspects of radiotherapy has been developed on an enhanced RAD8 computing system. The hardward configuration of the computer is described and the main features of the programs in the suite are discussed. The include: (a) beam data input systems for use with linear accelerators and cobalt units; (b) static and rotational teletherapy planning, with computer optimization in the static planning; (c) irregular field calculations with isodose visualization; (d) interstitial calculations including routines which will reconstruct a radium needle implant in three dimensions in addition to presenting the isodose distribution in any desired plane. The problems of implementing the programs on another computer system are discussed.

Computers↗
PubMed1987

Fitting curves to data using nonlinear regression: a practical and nonmathematical review.

Many types of data are best analyzed by fitting a curve using nonlinear regression, and computer programs that perform these calculations are readily available. Like every scientific technique, however, a nonlinear regression program can produce misleading results when used inappropriately. This article reviews the use of nonlinear regression in a practical and nonmathematical manner to answer the following questions: Why is nonlinear regression superior to linear regression of transformed data? How does nonlinear regression differ from polynomial regression and cubic spline? How do nonlinear regression programs work? What choices must an investigator make before performing nonlinear regression? What do the final results mean? How can two sets of data or two fits to one set of data be compared? What problems can cause the results to be wrong? This review is designed to demystify nonlinear regression so that both its power and its limitations will be appreciated.

Data Interpretation, Statistical↗
PubMed1996

Optima: a windows-based program for computer-aided optimization of controlled-release dosage forms.

The purpose of this work was to develop a computer program that assists optimization of controlled-release devices, both visually and mathematically, using response surface methodology (RSM). A Windows-based computer program, Optima, which interactively implemented a number of subroutines for the optimization procedure, was developed. Optima is an integrated, user-friendly, and graphically oriented program for pharmaceutical dosage form optimization. Central composite design is implemented in the program. First- and second-order models containing up to five variables can be fitted to the data. The user can also choose between linear and exponential individual desirability functions, and use them to construct an overall desirability function that combines all the response variables in a single response. The program can predict the optimum levels of experimental variables, with respect to individual responses and/or the overall desirability. Optima has been successfully used in the development of sustained-release AZT-loaded microspheres. During the optimization process, three experimental variables were investigated and four responses were measured. The experimental design was a central composite design that was generated by the program. The response values were used by the program to calculate the individual desirability functions, which were then combined into an overall desirability function. The individual responses as well as the overall desirability function were optimized by fitting to a second-order polynomial equation. The response surfaces were generated and optimum levels of the experimental variables were predicted. The observed responses of the optimized formulation were very close to those predicted by Optima. The program proved to be a very useful, integrated tool for optimization of the controlled-release microspheres.

Computer Graphics↗
PubMed2004

SAS programs for real-time RT-PCR having multiple independent samples.

Relative real-time reverse transcription PCR (RT-PCR) has become an important tool for quantifying changes in messenger RNA (mRNA) populations following differential development or stimulation of tissues or cells. However, the best methods for conducting such experiments and analyzing the resultant data remain an issue of discussion. In this report we describe an appropriate experimental methodology and the computer programs necessary to generate a meaningful statistical analysis of the combined biological and experimental variability in such experiments. Specifically, logarithmic transformations of raw fluorescence data from the log-linear portion of real-time PCR growth curves for both target and reference genes are analyzed using a SAS/STAT Mixed Procedure program specifically designed to give a point estimate of the relative expression ratio of the target gene with associated 95% confidence interval. The program code is open-source and is printed in the text.

Algorithms↗
PubMed1993

A multifunction and programmable computerized barostat.

A new computerized barostat allowing digestive tone measurement but also programmed distensions is described. The apparatus consists of a pump, driven by a computer, which injects or aspirates air in a flacid bag placed in a part of the gastrointestinal tract when relaxation or contraction occurs. Several parameters can be programmed for tone measurement: mean pressure, window pressure and air flow rate. Isovolumic or isobaric distensions can be performed using three modes: linear, stepwise or step by step with intermediate deflation. The height (mL or mmHg) of the steps and the duration of the distensions and the deflations can also be programmed. Three automatic and one manual safety systems are included. In comparison with previously described barostats the main feature of this apparatus is that it is entirely computerized and can be used for programmed distensions.

Atropine↗
PubMed1986

Kinematics properties of rapid aimed hand movements.

Generalized motor program theory and the models of Schmidt, Zelaznik, and Frank (1978), and Meyer, Smith, and Wright (1982) of speed-accuracy relationships in aimed hand movements require that the underlying acceleration-time patterns exhibit time rescalability, in which all acceleration-time functions in an aimed hand movement are generated from one rescalable pattern. We examined this property as a function of movement time in Experiment 1, and as a function of movement time and movement distance in Experiment 2. Both experiments failed to demonstrate strict time rescalability in acceleration-time patterns, with the time to peak positive acceleration being invariant across movement time. This suggests that time rescalability is not a necessary condition for the linear relation between speed and spatial variability. A second major finding was that the variability in distance traveled at the end of positive acceleration was independent of movement time, contrary to the symmetric-impulse-variability model of Meyer et al. (1982). The findings of both experiments suggest that the processes involved in decelerating the limb play an important, but yet to be understood, role in determining the linear speed-accuracy trade-off. Finally, these results suggest that generalized motor programs are not based on simple, time-rescalable acceleration patterns.

Journal Article↗
PubMed2001

Children with disabilities: a longitudinal study of child development and parent well-being.

This Monograph presents the results of the Early Intervention Collaborative Study, a longitudinal investigation of the cognitive and adaptive behavior development of children with developmental disabilities and the adaptation of their parents, extending from infancy through middle childhood. The study was designed to generate and test conceptual models of child and family development and contribute to the knowledge base that informs social policy and practice. The sample for the investigation reported here consists of 183 children with Down syndrome, motor impairment, developmental delay and their families who were recruited at the time of their enrollment in an early intervention program in Massachusetts or New Hampshire. Data were collected at five time points between entry to early intervention and the child's 10th birthday. Home visits were conducted at each time point and included child assessments, maternal interview, and questionnaires completed independently by both parents. Trajectories in children's development and parental well-being were analyzed using hierarchical linear modeling. Predictor variables were measured at age 3 years when children were exiting early intervention programs. Children's type of disability predicted trajectories of development in cognition, social skills, and daily living skills. Children's type of disability also predicted changes in maternal (but not paternal) child-related and parent-related stress. Beyond type of disability, child self-regulatory processes (notably behavior problems and mastery motivation) and one aspect of the family climate (notably mother-child interaction) were key predictors of change in both child outcomes and parent well-being. A different aspect of the family climate--family relations--also predicted change in child social skills. Parent assets, measured as social support and problem-focused coping, predicted change in maternal and paternal parent-related stress respectively. The implications of these findings for both the science of child development and the policies and practices of developmental intervention are discussed.

Adaptation, Psychological↗
PubMed1991

Intra-ocular concentration-time relationships of subconjunctivally administered gentamicin.

Eighty-nine patients scheduled for cataract removal or lens implantation were divided randomly into three groups. Each received 5, 10 or 20 mg gentamicin subconjunctivally at times varying between 0.2 and 19 hours pre-operatively. At surgery a sample of aqueous humour was obtained and analysed for gentamicin concentration. The data for each group were subjected to non-linear regression analysis to fit an open one-compartment pharmacokinetic model with first-order kinetics. A statistically acceptable fit was obtained. The average values of the pharmacokinetic parameters obtained from the single doses were used to simulate multiple-dose kinetics. The average target intra-ocular gentamicin concentrations and dosage interval were specified in the computer program, which subsequently allowed calculation of the dose required. This allowed the construction of a simple linear nomogram that can be used to read off the dose needed for handling specific clinical situations.

Aged↗
PubMed2001

Fast prediction of hydration free energies from molecular interaction fields.

A novel empirical model is presented that allows the fast computation of hydration free energies with high accuracy. The linear model is based upon the separation of the free energy of hydration into a cavity and an interaction term. The cavity contribution is modeled as a linear combination of molecular volume and surface terms. The interaction part is derived from the statistical three-dimensional (3D) free energy density and is modeled approximately as a molecular interaction field using the program GRID. A compression scheme is employed to represent this 3D information on the molecular surface by means of a linear combination of surface functions. A set of 81 small organic molecules with known experimental hydration free energies is used to determine the coefficients of the linear model by least squares regression. The fit is statistically significant yielding a correlation coefficient of 0.99, a root mean square error of 0.27 kcal/mol for the 81 molecules belonging to the training set, and 0.63 kcal/mol for an independent test set of 10 molecules.

Computer Simulation↗