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PubMed2001

Angiogenesis: a therapeutic target in arthritis.

A variety of pharmacological strategies are being subjected to clinical trial to inhibit neovascularization of solid tumors. Increased angiogenesis is also a key component of synovitis and bone modeling in arthritis. Molecular mechanisms and pathological consequences of blood vessel growth in arthritis are now being elucidated. Preclinical studies of angiogenesis inhibitors in animal models of inflammatory arthritis support the hypothesis that inhibition of neovascularization may reduce inflammation and joint damage. Clinical data are consistent with these models being predictive of efficacy in rheumatoid arthritis. However, controlled studies of specific anti-angiogenic agents in human arthritis remain limited. Further studies are required to demonstrate that pharmacological agents can effectively inhibit articular angiogenesis, and ameliorate inflammation and subsequent joint damage. Potential toxicity of angiogenesis inhibitors in reproduction, growth and development and wound repair may be circumvented by short-term or local application, or by targeting molecular mechanisms that are specific to pathological rather than physiological angiogenesis.

Angiogenesis Inhibitors↗

PubMedDate not supplied

Better functional mobility in community-dwelling elderly is related to D-hormone serum levels and to daily calcium intake.

The influence of calcitropic hormones on functional mobility has been studied in vitamin D (calcidiol) deficient elderly or elderly with a history of falls, however, data in community-dwelling independent vitamin D replete elderly are missing. We therefore assessed in an observational survey the association of calcidiol (25(OH)D3) and calcitriol (D-hormone / 1,25(OH)2D3) status as well as of daily calcium intake on functional mobility in older subjects We evaluated 192 women and 188 men, aged superior 70 years and living independently. Average Timed-up and go test (TUG-test) in seconds was taken as measure of functional mobility. Calcidiol and D-hormone serum concentrations and daily calcium intake were studied in multivariate controlled linear regression models with TUG-test performance as the dependent variable and/or as dichotomous variables (deficient vs. non-deficient, above vs. below the median, respectively). Subjects with low D-hormone serum concentrations took significantly more time to perform the TUG-test (low = 7.70s +/- 2.52 SD ; high = 6.70s +/- 1.29 SD; p = 0.004). In the linear multivariate controlled regression model increased D-hormone serum concentrations predicted better TUG-test performance (estimate -0.0007, p = 0.044). Participants with a calcium intake of > or =512 mg/day were significantly faster to perform the TUG-test than participants with a daily calcium intake of <512 mg/day (estimate:-0.43, p = 0.007). Other significant predictors of better TUG-test performance in both models were: male gender, less comorbid conditions, younger age, lower BMI, iPTH serum levels and creatinine clearance. Calcidiol serum levels were not associated with TUG-test performance. Higher D-hormone status and a calcium intake of > or =512 mg/day in community-dwelling independent older persons are significant determinants of better functional mobility. Therefore, to ensure optimal functional mobility, the care of older persons should address correction of D-hormone deficiency and increasing daily calcium intake.

Aged↗

PubMed1991

Re-organization of the immunoglobulin kappa gene on both alleles is not an obligatory prerequisite for Ig lambda gene expression in human cells.

Re-arrangement and expression of the immunoglobulin (Ig) genes in B cells occurs under an ordered developmental control. The sequential model of Ig light chain exclusion predicts that only after non-productive re-organization or deletion of both Ig kappa alleles would re-arrangement of Ig lambda gene segments occur. To prove this model, we asked whether expression of Ig lambda light chains is always associated with rearrangement and/or deletion of both Ig kappa alleles in human cells. Therefore, we established human diploid B-cell clones in vitro that produce Ig lambda light chains. Southern blot analysis of the Ig kappa alleles revealed that three Ig lambda expressing cell lines (out of six Ig lambda+ cell lines tested) harbour one Ig kappa allele in germline configuration. Furthermore, a 1.5 kb RNA derived from the germline Ig kappa locus was detected by Northern blot hybridizations. The results implicate that the mechanism of Ig light chain exclusion is not precisely sequential and that it does not necessarily need re-arrangement or deletion of both Ig kappa alleles as a prerequisite for Ig lambda light chain expression in human cells.

Alleles↗

PubMed1975

Threonine deaminase from Escherichia coli. II. Maturation and physical properties of the enzyme from a mutant altered in its regulation of gene expression.

The biosynthetic L-threonine deaminase (L-threonine hydrolase deaminating, EC 4.2.1.16) has been purified from Escherichia coli K12 regulatory mutant CU18. This mutant has properties that follow the predictions of the autogregulatory model previously proposed for the control of synthesis of the isoleucine-valine biosynthetic enzymes. The autoregulatory model specifies that L-threonine deaminase participates in the control of the expression of the ilv ADE gene cluster as well as the ilv B gene and ilv C gene, which constitute three separate units of regulation. The single mutation in strain CU18 results in altered regulation of ilv gene expression and in the production of an altered L-threonine deaminase. The immature form of the enzyme purified from mutant CU18 exhibits an altered response to L-valine, a maturation-inducing ligand. The native form of the mutant is altered in its apparent Km for L-threonine and in its response to the effects of L-valine and L-isoleucine upon catalytic activity. The mutant and wild type L-threonine deaminases differ in the apoenzyme formed as a consequence of alkaline dialysis. Dialysis of the mutant enzyme yields an apoenzyme mixture, apparently of dimers and monomers, while the wild type enzyme yields only dimers. The CU18 L-threonine deaminase, is however, indistinguishable from the wild type enzyme in molecular weight and subunit composition.

Chromatography, Ion Exchange↗

PubMed1985

[Action of radiation on the lung. Classic concepts and current interpretations].

The effects of irradiation on the pulmonary system are analyzed according to the classical radiobiological theories and the new ones. Special emphasis is put on the lineal-quadratic model which predicts the possibility of a greater tumor control without increasing the damage to the normal lung tissue, based on the differences between the survival curves for acute and late effects of irradiation. The clinical applications of the new radiobiological concepts can be carried out in the treatment of lung cancer and other neoplasms, especially those using total body irradiation.

Humans↗

PubMed2026

[Effects and mechanisms of Jiawei Yigong San on the Th17/Treg balance in food allergy].

Objective To explore the effects and mechanisms of Jiawei Yigong San (JWYGS) on the T helper type 17 (Th17)/regulatory T (Treg) cell balance in food allergy (FA). Methods Active components, action targets of JWYGS, and FA-related targets, were screened via network pharmacology. Overlapping targets between JWYGS and FA were used to construct a protein-protein interaction (PPI) network. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were performed to predict key signaling pathways. Molecular docking was conducted to validate the binding affinity between the main active components and the predicted targets. Mice were randomly divided into control group, model group, JWYGS low-dose, medium-dose, and high-dose groups, and dexamethasone (DXM) group. An ovalbumin (OVA)-induced FA model was established. During the OVA challenge period, mice received daily intragastric administration, after which allergy and diarrhea scores were assessed. Small intestinal pathology was evaluated by HE staining. Serum ovalbumin-specific immunoglobulin E (OVA-sIgE), interleukin 6 (IL-6), IL-17, IL-2, and IL-10 were measured by ELISA. Small intestinal IL-6, IL-17, and IL-10 protein expression was detected by immunohistochemistry. Splenic Th17 and Treg cells were quantified by flow cytometry, and the Th17/Treg ratio was calculated. The mRNA expression of IL-6, retinoic acid receptor-related orphan receptor γt (RORγt), and forkhead box protein P3 (FOXP3) in the small intestine was detected by qPCR. Results Network pharmacology identified 235 active components of JWYGS and 136 common targets. GO and KEGG enrichment analyses highlighted cytokine response and Th17 differentiation. Molecular docking confirmed stable binding between core components and targets. Compared with the control group, the model group exhibited aggravated allergy and diarrhea scores, marked small intestinal inflammation and mucosal damage, elevated serum levels of OVA-sIgE, IL-6, IL-17 and IL-2, along with increased splenic Th17 cell frequency and Th17/Treg ratio. Intestinal IL-6 and IL-17 protein levels as well as IL-6 and RORγt mRNA expression were upregulated, whereas serum IL-10 levels were decreased, and intestinal expression of IL-10 protein and FOXP3 mRNA was downregulated. After JWYGS treatment, allergy and diarrhea scores were significantly reduced. Small intestinal inflammation and mucosal damage were alleviated. Serum levels of OVA-sIgE, IL-17, IL-6 and IL-2, Th17 cell frequency and the Th17/Treg ratio, intestinal IL-6 and IL-17 protein levels were decreased. IL-6 and RORγt mRNA expression was downregulated. Serum IL-10 levels were increased and intestinal expression of IL-10 protein and FOXP3 mRNA was upregulated. Moreover, the JWYGS high-dose group demonstrated comparable efficacy to the DXM group. Conclusion JWYGS can ameliorate symptoms and reverse the Th17/Treg imbalance in FA mice, potentially by inhibiting IL-6 transcription and regulating RORγt/FOXP3 expression.

Animals↗

PubMed1996

A compartmental brain model for chemical transport and CO2 controlled blood flow.

A compartmental transport model is developed, capable of predicting the evolution of CO2, HCO-3 and H+ in the cerebrovascular system. In the model, the transport of these components is simulated at a subset of three compartments: cerebrospinal fluid (CSF), capillary-choroid plexus and brain tissue, belonging to a seven compartmental assembly representing the entire brain. The remaining ones are; artery, vein, venous sinus and jugular bulb. The model accounts for advection associated with non-steady perfusion fluxes across semi-previous boundaries. Pressures, associated with perfusion, are solved in the seven-compartment model. The three-compartment transport model also takes into account changes in compartmental volume due to displacement of its boundaries, diffusion through boundaries and rate of generation of substances by chemical reactions. A first-order reaction rate is assumed in the CSF compartment. A parameter estimation method is then developed to assess boundary diffusivities from time-averaged observed values of perfusion pressure, tension of carbon dioxide, pH values, and concentration of free hydrogen and bicarbonate ions. An equation of state describing the regulation of flow from arteries to capillaries, as a function of CO2 tension in the CSF, is then suggested. Upon solving all coupled mass balance equations, and for a pre-evaluated perfusion pressure in the artery and capillary compartments, one can estimate the change in arteries to capillaries conductance at every time step. Boundary diffusivities between the capillary, cerebrospinal fluid and brain tissue compartments, were estimated. A sensitivity analysis proves the consistency between model predictions and available clinical observations, this, in terms of the influence of the parameter associated with CO2 metabolic rate on CO2 tension. It was shown that decrease of this tension caused an abrupt pressure fall at the first instant which later increased to an asymptotic value. This, however, was not evident in the capillaries at which pressure slightly falls and then remains constant.

Bicarbonates↗

PubMedDate not supplied

Relaxation electromechanical delay of the quadriceps during selected movement velocities.

The purpose of this study was to quantify the time between the cessation of EMG activity and cessation of torque production, or relaxation electromechanical delay, (R-EMD) of the quadriceps at three angular movement velocities. A Biodex dynamometer passively moved the right knee of 25 males through a given range at three velocities (10, 60 and 120 degrees per second). Subjects were instructed to actively extend their knees to a visual target, then to immediately relax. Biodex torque and position data, as well as surface EMG from the right Vastus Medialis (VM), Rectus Femoris (RF) and Vastus Lateralis (VL) were sampled simultaneously. EMG cessation was determined when activity fell below a threshold based on the muscle's resting EMG. Torque cessation was determined when the slope of the relaxation curve decreased to 10% of the initial value. R-EMD time for each quadriceps head at each velocity was determined by calculating the difference between these two times. To examine reliability, subjects were retested four days later. Approximately two thirds of the subjects were unable to consistently perform the motor task of abrupt relaxation at some or all of the tested velocities. This variability was ascribed to motor control issues. Average R-EMD times for all subjects, muscle segments and velocities ranged from 249 +/- 68 ms to 276 +/- 51 ms during the first test session, and 239 +/- 46 ms to 300 +/- 59 ms during the second session. These data are important in identification of physiologically meaningful cessation of muscle contraction, and may be beneficial in research studies focusing on the areas of motor control and motor learning, computerized movement analysis, and prediction models for the determination of muscular force from the EMG signal.

Adult↗

PubMed1996

Effect of vaccination against Aujeszky's disease compared with test and slaughter programme: epidemiological and economical evaluations.

In January 1990, a 6-year program was initiated to eliminate endemic Aujeszky's Disease virus (ADV) infection from the pig herds in an area of Northern Germany, bordering Southern Denmark, with intensive pig farming. In the first 3 years of the campaign, an intensive compulsory vaccination program, with glycoprotein I (gI)-deleted vaccines, of all pigs in the area was employed. Beginning in June 1990 and for the first 3 years of the project, approximately 200 herds randomly selected from all herds in the area, were serologically tested each quarter. In each farrow-to-feeder (FAFE), feeder-to-finish (FEFI) and farrow-to-finish (FAFI) herd, 20 female breeding pigs, 20 finishing pigs (> or = 50 kgs liveweight) and 10 female breeding pigs and 10 finishing pigs, respectively, were blood sampled. The sera were tested by the Herd-Check Anti-PRV(S) ELISA test (IDDEX Inc., ME). Sera positive to this test were examined by the HerdCheck Anti-ADV gI-ELISA test (IDDEX Inc., ME). Data on potentially confounding management factors were collected through a pilot-tested questionnaire, administered to farmers by 2 veterinarians who blood sampled the pigs. For fattening herds (FEFI and fattening sections of FAFI herds), the association between the odds of > or = 1 gI+ finishing pigs and the time between initiation of the program in the area and sampling date (a surrogate for the effect of the program) was modelled using ordinary logistic regression. The association between the odds of gI+ females in seropositive (> or = gI+ females) FAFE and FAFI herds and time since initiation of the program was investigated with logistic-binomial regression models. Results of the study show that the longer the period from the beginning of compulsory vaccination to the date the herd was sampled the lower the odds of gI+ fattening herds and gI+ female breeding pigs in herds of the area. The beneficial effect of mass vaccination on the reduction of ADV spread was accounted for by this relationship. For fattening herds this relationship appeared curvilinear, with the reduction in the log-odds being more rapid in the 1st year of the program. This non-linear pattern indicates that for the elimination of the risk of ADV-infection from fattening herds of the area, the mass vaccination program should be complemented with additional measures such as test-and-slaughter of infected breeding pigs. A computerized economical model to estimate the effects of ADV-infection at the herd and area level has been developed. The analytical structure consists of a basic epidemiological model linked to an economic estimation framework. The economic model predictions allow priorities to be given to alternative control strategies. Mass vaccination of all pigs in regions with endemically infected herds followed by test-and-removal of seropositive animals is the most cost-effective way to control the spread of ADV within the swine population. Other possible control strategies such as intensive vaccination or complete test-and-removal all had higher overall costs, either because of the less efficient production, or because of the high costs of straight test-and-removal.

Abattoirs↗

PubMed1996

Neither too sweet nor too sour: problem peers, maternal control, and problem behavior in African American adolescents.

This study examined whether maternal control protects African American adolescents from the negative influence of problem peers. Two forms of control were examined, behavioral control and psychological control. It was hypothesized that there would be a curvilinear relation between control and adolescent problem behavior, with the strength of the relationship and the amount of control optimal for adolescent development varying by the level of peer problem behavior. In general, data supported this model, particularly in regard to behavioral control, where the predicted curvilinear interaction occurred even after controlling for initial levels of problem behavior. The predicted curvilinear interaction between psychological control and peer problem behavior was statistically significant if initial levels of problem behavior were not controlled for but was not significant after controlling for initial problem behavior. These findings suggest that high-quality parenting can play a modest but critical role in the face of environmental adversity.

Adolescent↗

PubMed1998

Airborne contaminant exposure control in a partitioned work environment by exhaust ventilation systems.

The evaluation of contaminant removal effectiveness can play a key role in a working environment quality investigation and in remediation efforts. In this study a computer simulation technique was developed for assessing the efficiency of contaminant removal within a partitioned working environment. To determine the effect of the physical parameters of each partitioned space on contaminant removal effectiveness, a relative contaminant concentration unit was used to show the simulation results. In addition, tracer gas techniques were adopted to validate the accuracy of the prediction model. A comparison of measured CO2 concentrations in a controlled environment chamber with the results of a simulation model is presented. This study investigated the partition configuration of work environment and environment parameters including openings operation, constant concentration, and exhaust air volume mode. Results indicated that variations of the above three parameters can produce great differences in overall ventilation performance. Through this type of study, the interaction of airflow and contaminant concentration between partitioned spaces can be understood in advance and adequate knowledge can be provided to maintain a high-quality and healthy environment for workers.

Air Movements↗

PubMed1999

Respiratory health and fluoride exposure in different parts of the modern primary aluminum industry.

OBJECTIVE: The aim of this cross-sectional study was to investigate possible acute and long-term respiratory health effects of work at different working places in the primary aluminum industry. METHOD: A cross-sectional study was carried out on 78 potroom workers, 24 foundry workers, and 45 carbon-plant workers (n = 147, exposed group), and 56 control workers (watchmen, craftsmen, office workers, laboratory employees) of a modern German prebake aluminum plant. The survey consisted of pre- and postshift spirometric and urinary fluoride measurements. RESULTS: Potroom workers had significantly lower preshift results with regard to forced vital capacity (FVC, 99. 5% versus the 107.2% predicted; P < 0.05) and peak expiratory flow (PEF, 85.2% versus the 98.4% predicted; P < 0.01) as compared with controls. In a multiple regression model a small but significant negative correlation was found between postshift urinary fluoride concentrations and FVC, FEV(1), and PEF. Across-shift spirometric changes were observed only in FVC among carbon-plant workers (103.0 +/- 13.3% predicted preshift value versus 101.2 +/- 13.6% predicted postshift value; P < 0.05). CONCLUSIONS: The results suggest that lung function impairment in the modern primary aluminum industry may be only partly due to fluoride exposure and that working in aluminum carbon plants may cause acute lung function changes.

Adult↗

PubMed2004

Evaluation of a Clostridium perfringens predictive model, developed under isothermal conditions in broth, to predict growth in ground beef during cooling.

Proper temperature control is essential in minimizing Clostridium perfringens germination, growth, and toxin production. The U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) offers two options for the cooling of meat products: follow a standard time-temperature schedule or validate that alternative cooling regimens result in no more than a 1-log(10) CFU/g increase of C. perfringens and no growth of Clostridium botulinum. A mathematical model developed by Juneja et al. (Food Microbiol. 16:335-349, 1999) may be helpful in determining if the C. perfringens performance standard has been achieved, but this model has not been extensively validated. The objective of this study was to validate the Juneja 1999 model in ground beef under a variety of changing temperature and temperature abuse situations. The Juneja 1999 model consistently underpredicted growth of C. perfringens during exponential cooling of ground beef. The model also underpredicted growth of C. perfringens in ground beef cooled at two different rates. The results presented here show generally good agreement with published data on the growth of C. perfringens in similar products. The model error may be due to faster-than-expected exponential growth rates in ground beef during cooling or an error in the mathematical formulation of the model.

Animals↗

PubMed2002

Prediction and overview of the RpoN-regulon in closely related species of the Rhizobiales.

BACKGROUND: In the rhizobia, a group of symbiotic Gram-negative soil bacteria, RpoN (sigma54, sigmaN, NtrA) is best known as the sigma factor enabling transcription of the nitrogen fixation genes. Recent reports, however, demonstrate the involvement of RpoN in other symbiotic functions, although no large-scale effort has yet been undertaken to unravel the RpoN-regulon in rhizobia. We screened two complete rhizobial genomes (Mesorhizobium loti, Sinorhizobium meliloti) and four symbiotic regions (Rhizobium etli, Rhizobium sp. NGR234, Bradyrhizobium japonicum, M. loti) for the presence of the highly conserved RpoN-binding sites. A comparison was also made with two closely related non-symbiotic members of the Rhizobiales (Agrobacterium tumefaciens, Brucella melitensis). RESULTS: A highly specific weight-matrix-based screening method was applied to predict members of the RpoN-regulon, which were stored in a highly annotated and manually curated dataset. Possible enhancer-binding proteins (EBPs) controlling the expression of RpoN-dependent genes were predicted with a profile hidden Markov model. CONCLUSIONS: The methodology used to predict RpoN-binding sites proved highly effective as nearly all known RpoN-controlled genes were identified. In addition, many new RpoN-dependent functions were found. The dependency of several of these diverse functions on RpoN seems species-specific. Around 30% of the identified genes are hypothetical. Rhizobia appear to have recruited RpoN for symbiotic processes, whereas the role of RpoN in A. tumefaciens and B. melitensis remains largely to be elucidated. All species screened possess at least one uncharacterized EBP as well as the usual ones. Lastly, RpoN could significantly broaden its working range by direct interfering with the binding of regulatory proteins to the promoter DNA.

Bacterial Proteins↗

PubMed1995

Adaptive control of therapeutic drug regimens relations between clinical situations: outcomes and simulations using nonlinear dynamic models.

With Bayesian modeling and adaptive control of drug dosage regimens, serum and peripheral drug concentrations can be predicted in clinical situations using linear pharmacokinetic compartmental models (PK). Recently, several pathophysiologic and pharmacodynamic nonlinear models (PD) have been developed. The present report illustrates both their utility and limits for the computation of effects in clinical situations in the setting of actual routine and acute patient care. Patients who received therapy with aminoglycosides or/and vancomycin were selected. For each patient, after estimation of individual pharmacokinetic parameters, the computed outputs of the linear compartmental pharmacokinetic model were used as inputs for 2 different a priori nonlinear dynamic models: 1) the EFFECT modeling program, using a Hill model, and 2) the BACTCIDE program, which is a combination of a simple growth model for the organism and a Hill effect model considering both the microorganism, the antibiotic, and the patient's minimal inhibitory concentration (MIC). The programs (1) and (2) can use as inputs the computed concentrations from any of three compartments: central, peripheral, or a spherical diffusion compartment to compute drug diffusion into endocardial vegetations or abscesses. The EFFECT program can be used alone for the evaluation of drug effects. The BACTCIDE program illustrates differences in activity between concentration-dependent and time-dependent antibiotics. Such nonlinear programs are very sensitive to the MIC values.

Aged↗

PubMed2005

Is consumption of breakfast associated with body mass index in US adults?

OBJECTIVE: To test the hypothesis that breakfast consumption is associated with weight status measured by body mass index in US adults. DESIGN: Analyses of data from the National Health and Nutrition Examination Survey, 1999-2000. PARTICIPANTS/SETTING: Men and women aged > or = 19 years (N=4,218), excluding pregnant and/or lactating women. STATISTICAL ANALYSES PERFORMED: SAS (release 8.1, 2000, SAS Institute Inc, Cary, NC) and SUDAAN (release 8.0.2, 2003, Research Triangle Institute, Research Triangle Park, NC) software were used to calculate sample-weighted means, standard errors, and population percentages of breakfast consumers. Multiple logistic and linear regression models, with controls for covariates, were used to determine the predictability of body mass index from breakfast consumption and from inclusion of ready-to-eat cereal (RTEC) in the breakfast meal. RESULTS: Breakfast consumers were more likely than breakfast nonconsumers to be older, female, white, nonsmokers, regular exercisers, and trying to control their weight. For women, daily energy intake was higher among breakfast consumers than among breakfast nonconsumers; for both men and women, energy intake from fat among RTEC breakfast consumers was significantly lower than among non-RTEC breakfast consumers, whereas energy from carbohydrate among RTEC breakfast consumers was significantly higher than among non-RTEC breakfast consumers. For women, the odds ratios for BMI > or = 25 were lower for breakfast consumers (odds ratio = 0.76) and RTEC breakfast consumers (odds ratio = 0.70) compared with breakfast nonconsumers and non-RTEC breakfast consumers, respectively, after adjusting the models for covariates. When RTEC consumption was added as a covariate, breakfast consumers no longer exhibited significantly lower odds ratios compared with breakfast nonconsumers. Furthermore, regression analyses supported an inverse association between RTEC breakfast consumption and body mass index in women (regression coefficient = -0.37, P<.01) after adjusting for covariates. CONCLUSIONS: When we document the association of breakfast consumption with lower prevalence of overweight and obesity, types of meal should be considered as an important determinant. RTEC breakfast consumption, associated with a desirable macronutrient profile for preventing obesity, predicted weight status in women, but not in men. In addition to sex difference in the association of breakfast consumption and RTEC breakfast consumption with lower prevalence of overweight, the effects of physiological variables and health-related behaviors on the relationship between total and RTEC intake at breakfast and weight status, remain to be established.

Adult↗

PubMed2005

Model-based analysis of jaw-movement kinematics using jerk-optimal criterion: simulation of human chewing cycles.

Large intra- and/or inter-individual variability in human masticatory motor behaviors may reduce objectivity in assessing normality/abnormality for jaw movements. Analytical simulation by kinematic modeling based on a universally accepted objective criterion is a potentially useful clinical tool for credible diagnostic quantification of jaw motion. This study aimed to test whether a minimum-jerk (maximum-smoothness) model could accurately simulate the kinematics in each separate gum-chewing cycle of 10 healthy adults, and if so, to examine whether simulation errors reflected an extent of abnormality for chewing movements for 10 patients caused by temporomandibular joint disorders (TMD). The model predicted the lower incisor-point movements of the control group with reasonable accuracy. Overall, the prediction errors for the patients group were greater than the control group, demonstrating that prediction errors for jaw opening velocity were sensitive to the criteria for joint disorders. It was concluded that the present simulation emerged as being capable of scaling the not so smooth masticatory jaw movements performed in the presence of TMD.

Adult↗

PubMed1995

Evolution of drug consumption in a sample of adolescents: the predictive capacity of the genesis model.

This paper analyzes the predictive capacity of the genesis model for drug consumption constructed by the authors in an attempt to identify the characteristics of a drug consumption risk population. Several years' research have shown the model's validity in explaining drug consumption, a behavior understood as one of the many for possible use by adolescents to adapt to the environment in which they develop. The potential for behavior which deviates from the norm depends on a variety of factors considered in the model (including level of self-control, attitudes to drugs, or the existence of peers to reinforce such behavior). The predictive capacity of the model is analyzed in a longitudinal study carried out on a sample of 476 students (238 men and 238 women).

Adolescent↗