Linear equality constraints: Reformulations of criterion related profile analysis with extensions to moderated regression for multiple groups.

Criterion-related profile analysis (CPA) is a least squares linear regression technique for identifying a criterion-related pattern (CRP) among predictor variables and for quantifying the variance accounted for by the pattern. A CRP is a pattern, described by a vector of contrast coefficients, such that predictor profiles with higher similarity to the pattern have higher expected criterion scores. A review of applications shows that researchers have extended the analysis to meta-analyses, logit regression, canonical regression, and structural equation modeling. It also reveals a need for better methods of comparing CRPs across populations. While the original method for identifying the CRP tends to underestimate the variance accounted for by pattern only, both the pattern identified by the original method and the pattern identified by the new method proposed here have useful and complementary interpretations. Imposing linear equality constraints on regression coefficients yields a more accurate method of estimating the variance accounted for by pattern only, and this constrained approach leads to moderated regression models for investigating whether the CRP is the same in two or more populations. Finally, we show how the elements in Cronbach and Gleser's (1953) classic profile decomposition are related to the linear regression model and the CPA model. Academic ability tests as predictors of college GPA are used to illustrate the analyses. Implications of the profile pattern models for psychological theory and applied decision-making are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Celastrol alleviates metabolic disturbance in high-fat diet-induced obese mice through increasing energy expenditure by ameliorating metabolic inflammation.

Celastrol, a natural triterpene, has been shown to treat obesity and its related metabolic disorders. In this study, we first assessed the relationship between the antiobesity effects of celastrol and its antiinflammatory activities. Our results showed that celastrol can reduce weight gain, ameliorate glucose intolerance, insulin resistance, and dyslipidemia without affecting food intake in high-fat diet-induced obese mice. A CLAMS was used to clarify the improvement of metabolic profiles was attribute to increased adipose thermogenesis after celastrol treatment. Further studies found that celastrol decreased the infiltration of macrophage as well as its inflammatory products (IL-1ß, IL-18, MCP-1α, and TNF-α) in liver and adipose tissues, which also displayed an obvious inhibition of TLR3/NLRP3 inflammasome molecules. This study demonstrated that celastrol could be a potential drug for treating metabolic disorders, the underlying mechanism is related to ameliorating metabolic inflammation, thus increasing body energy expenditure.

Addressing Quantitative and Qualitative Hypotheses Using Regression Models with Equality Restrictions and Predictors Measured in Common Units.

In regression, some or all of the predictors may be measured in common units: e.g. X1 = carbohydrate calories, X2 = protein calories, X3 = fat calories. Such predictors can occur in disciplines as diverse as business, economics, education, medicine, nutrition, psychology, sport science, etc. Predictors in common units can lead to unique quantitative and qualitative hypotheses that can be addressed by imposing equality restrictions on the regression weights (e.g. b1=b2=b3). A simple device, total score substitution, is available for constraining regression coefficients to be equal in a variety of regression applications. Applications to linear, moderated linear, and polynomial models are described, but extensions to generalized linear models and multilevel linear models are also possible. Total score substitution in linear and moderated regression is illustrated using high school coursework and mathematics achievement data. Data, code (R, SPSS, SAS), and output are publicly available.

Graphical Calculation of Estimated Energy Expenditure in Burn Patients.

BACKGROUND: Historically, estimated energy expenditure (EEE) has been related to the percent of body surface area burned. Subsequent evaluations of these estimates have indicated that the earlier formulas may overestimate the amount of caloric support necessary for burn-injured patients. Ireton-Jones et al derived 2 equations for determining the EEE required to support burn patients, 1 for ventilator-dependent patients and 1 for spontaneously breathing patients. Evidence has proved their reliability, but they remain challenging to apply in a clinical setting given the difficult and cumbersome mathematics involved. This study aims to introduce a graphical calculation of EEE in burn patients that can be easily used in the clinical setting. METHODS: The multivariant linear regression analysis from Ireton-Jones et al yielded equations that were rearranged into the form of a simple linear equation of the type y = mx + b. By choosing an energy expenditure and the age of the subject, the weight was calculated. The endpoints were then calculated, and a graph was mapped by means of Adobe FrameMaker. RESULTS: A graphical representation of Ireton-Jones et al's equations was obtained by plotting the weight (kg) on the y axis, the age (years) on the x axis, and a series of parallel lines representing the EEE in burn patients. The EEE has been displayed graphically on a grid to allow rapid determination of the EEE needed for a given patient of a designated weight and age. Two graphs were plotted: 1 for ventilator-dependent patients and 1 for spontaneously breathing patients. Correction factors for sex, the presence of additional trauma, and obesity are indicated on the graphical calculators. CONCLUSIONS: We propose a graphical tool to calculate caloric requirements in a fast, easy, and portable manner.

Optimal clinical trial design based on a dichotomous Markov-chain mixed-effect sleep model.

D-optimal designs for discrete-type responses have been derived using generalized linear mixed models, simulation based methods and analytical approximations for computing the fisher information matrix (FIM) of non-linear mixed effect models with homogeneous probabilities over time. In this work, D-optimal designs using an analytical approximation of the FIM for a dichotomous, non-homogeneous, Markov-chain phase advanced sleep non-linear mixed effect model was investigated. The non-linear mixed effect model consisted of transition probabilities of dichotomous sleep data estimated as logistic functions using piecewise linear functions. Theoretical linear and nonlinear dose effects were added to the transition probabilities to modify the probability of being in either sleep stage. D-optimal designs were computed by determining an analytical approximation the FIM for each Markov component (one where the previous state was awake and another where the previous state was asleep). Each Markov component FIM was weighted either equally or by the average probability of response being awake or asleep over the night and summed to derive the total FIM (FIM(total)). The reference designs were placebo, 0.1, 1-, 6-, 10- and 20-mg dosing for a 2- to 6-way crossover study in six dosing groups. Optimized design variables were dose and number of subjects in each dose group. The designs were validated using stochastic simulation/re-estimation (SSE). Contrary to expectations, the predicted parameter uncertainty obtained via FIM(total) was larger than the uncertainty in parameter estimates computed by SSE. Nevertheless, the D-optimal designs decreased the uncertainty of parameter estimates relative to the reference designs. Additionally, the improvement for the D-optimal designs were more pronounced using SSE than predicted via FIM(total). Through the use of an approximate analytic solution and weighting schemes, the FIM(total) for a non-homogeneous, dichotomous Markov-chain phase advanced sleep model was computed and provided more efficient trial designs and increased nonlinear mixed-effects modeling parameter precision.

Methodological comparison of in vitro binding parameter estimation: sequential vs. simultaneous non-linear regression.

PURPOSE: Analysis of simulated data was compared using sequential (NLR) and simultaneous non-linear regression (SNLR) to evaluate precision and accuracy of ligand binding parameter estimation. METHODS: Commonly encountered experimental error, specifically residual error of binding measurements (RE), experiment-to-experiment variability (BEV) and non-specific binding (B(NS)), were examined for impact of parameter estimation using both methods. Data from equilibrium, dissociation, association and non-specific binding experiments were fit simultaneously (SNLR) using NONMEM VI compared to the common practice of analyzing data from each experiment separately and assigning these as exact values (NLR) for estimation of the subsequent parameters. RESULTS: The greatest contributing factor to bias and variability in parameter estimation was RE of the measured concentrations of ligand bound; however, SNLR provided more accurate and less bias estimates. Subtraction of B(NS) from total ligand binding data provided poor estimation of specific ligand binding parameters using both NLR and SNLR. Additional methods examined demonstrated that the use of SNLR provided better estimation of specific binding parameters, whereas there was considerable bias using NLR. NLR cannot account for BEV, whereas SNLR can provide approximate estimates of BEV. CONCLUSION: SNLR provided superior resolution of parameter estimation in both precision and accuracy compared to NLR.

Adult sarcomas: a missed opportunity for sustained cooperative group translational and clinical research.

Preclinical advances offer an opportunity to further reduce morbidity and mortality from sarcomas over the next decade. Since no single institution or North American cooperative oncology group has the expertise or patient resources for histology-specific clinical and translational research on adult sarcomas, efforts have been made to develop funding from the National Cancer Institute (NCI). One such initiative was the Intergroup Coalition Against Sarcomas (ICAS), which, building upon the strengths of the multimodality cooperative oncology groups, provided an infrastructure for broad participation by investigators from all treatment disciplines in protocol development and patient entry. However, despite an excellent evaluation in formal peer review, the Division of Cancer Treatment of NCI has ended this initiative claiming insufficient available funds--to the detriment of adult sarcoma patients now and in the future.

Pseudo-latex allergy associated with "latex" paint exposure: a potential cause of iatrogenic disability.

OBJECTIVE: We sought to describe outcomes for three health care workers with natural rubber latex (NRL) allergy reporting illness after exposure to latex paint. METHODS: We undertook a retrospective review of medical and occupational histories, diagnostic, treatment, and work recommendations. Outcomes included lost time, workers compensation indemnity costs, and return to work. RESULTS: None of the paints contained NRL. Cases 1 and 2 initially were misdiagnosed as suffering allergic reactions to NRL, resulting in 7 and 23 months lost time, $15,790 and $139,000 indemnity costs, respectively, and both failing to return to work. Case 3 was correctly diagnosed as not exposed to NRL, with only several lost days, no indemnity costs, and continued to work. CONCLUSIONS: The failure to recognize that synthetic paints do not contain NRL can lead to misdiagnosis, inappropriate exposure, and work avoidance recommendations and iatrogenic disability.

Improving cardiovascular disease prevention and management in Africa: issues to consider for the 21st century.

There is substantial evidence that cardiovascular diseases, and their associated risk factors, are becoming an increasing threat to the health of a large portion of the populace in many areas of Africa, particularly sub-Saharan Africa. If not adequately addressed, this epidemic will place an even greater burden on the poor economies and weak public health infrastructures of this continent. Important strategies for curtailing this epidemic will include primordial, primary, and secondary prevention, population-based prevention programs, improved research and surveillance, and increased governmental accountability for the adequate appropriation of public health.

[The value of CT and MRI in the assessment of basal encephaloceles in children]. / Apport du CT et de l'IRM dans l'évaluation des céphalocèles basales de l'enfant.

Basal cephaloceles of the child are rare pathologies which require accurate preoperative imaging work-up. The CT and MR studies of six children with surgically proven basal cephalocele were retrospectively reviewed to evaluate the role of CT and MR in the preoperative work-up of a basal cephalocele of the child. In five patients, MR allowed to define the nature and topography of the cephalocele, and allowed an accurate depiction of the optic tract, ante- and post-hypophysis and associated agenesis of corpus callosum when present. 3-D CT allowed in one case a more precise depiction of the basal bony defect. MRI allows in a non invasive and non ionising way the best depiction of herniating meninges, brain or ventricles as well as associated cerebral anomalies.