Brain trauma exposure for American tackle football players 5 to 9 and 9 to 14 years of age.

American football helmets used by youth players are currently designed and tested to the same standards as professionals. The National Operating Committee on Standard and Safety requested research aiming at understanding the differences in brain trauma in youth American football for players aged five to nine and nine to fourteen years old to inform a youth specific American football standard. Video analysis and laboratory reconstructions of head impacts were undertaken to measure differences in head impact frequency, event types, and magnitudes of maximum principal strain (MPS) for the two age groups. Overall frequencies and frequencies for five categories of MPS representing different magnitudes of risk were tabulated. The MPS categories were very low (<0.08), low (0.08-0.169), medium (0.17-0.259), high (0.26-0.349) and very high (>0.35). Both cohorts experienced a majority of head impacts (>56%) at very low magnitude of MPS. Youth American football players aged 9-14 yrs. sustained a greater frequency of head impacts at MPS between 0.08 and 0.169 % associated with changes in brain structure and function. There were no differences in overall frequency, or in frequency of head impacts in other categories of MPS. The proportion of impacts considered injurious (MPS > 0.08) was greater in the 5-9 group (44%), than the 9-14 group (39%), and impacts above 0.35 % were only reported for the younger age group. The larger helmet-to-shoulder ratio in the younger age groups may have contributed to this finding suggesting that youth American football players under the age of nine would benefit from a child-specific football helmet.

Qualitative and quantitative analyses of resin-bound organic compounds.

Methods for qualitative and quantitative analyses of resin-bound organic compounds are essential tools for chemistry development in solid-phase combinatorial and parallel syntheses. Here we discuss the use of gel-phase 19F NMR, the fluoride ion-selective electrode method, and spectrophotometry for monitoring solid-phase reactions. Our results indicate that the application of these diverse methods for analyzing the outcome of solid-phase combinatorial synthesis are sensitive and conclusive.

Backside nonconformity and locking restraints affect liner/shell load transfer mechanisms and relative motion in modular acetabular components for total hip replacement.

Nonconformity between the polyethylene liner and the metal shell may exist in modular acetabular components by design, due to manufacturing tolerances, or from locking mechanisms that attach the polyethylene liner to the metal shell. Relative motion at the liner/shell interface has been associated with backside wear, which may contribute to osteolysis which has been clinically observed near screw holes. The purpose of this study was to investigate the effect of nonconformity and locking restraints on the liner/shell relative motion and load transfer mechanisms in a commercially available, metal-backed acetabular component with a polar fenestration. The finite element method was used to explore the hypothesis that backside nonconformity and locking restraints play important roles in long-term surface damage mechanisms that are unique to modular components, such as backside wear and liner extrusion through screw holes. The three-body quasi-static contact problem was solved using a commercially available explicit finite element code, which modeled contact between the femoral head, polyethylene liner, and the metal shell. Four sets of liner boundary conditions were investigated: no restraints, rim restraints, equatorial restraints, and both rim and equatorial restraints. The finite element model with a conforming shell predicted between 8.5 and 12.8 microm of incremental extrusion of the polyethylene through the polar fenestration, consistent with in vitro experiments of the same design under identical loading conditions. Furthermore, idealized rim and/or equatorial liner restraints were found to share up to 71% of the load across the liner/shell interface. Consequently, the results of this study demonstrate that backside nonconformity and locking restraints substantially influence backside relative motion as well as load transfer at the liner/shell interface.

Estimating local-area needs for psychiatric care: a case study.

BACKGROUND: Different approaches to estimating local catchment-area needs for psychiatric services are illustrated and compared. METHOD: Data from an epidemiological morbidity survey of a random sample of 496 adults were available, as were actual service utilisation rates. Four types of utilisation were modelled (i.e. overall, out-patient, in-patient, emergency clinic) using social indicators available from Statistics Canada census-tract data. Finally, a case-control study compared out-patients from a deprived and an affluent catchment area, matched case by case for primary diagnosis, age, sex and residential status (n = 52). RESULTS: Modelling proved highly predictive of utilisation, the overall-use model accounting for 73% of the variance. The case-control study indicated a higher rate of Axis II traits, substance abuse and needs for social care in the deprived catchment area. CONCLUSIONS: Resource allocation based on the social indicators modelling method was more consistent with sensible distribution of human resources. None of the methods, however, appear to reflect adequately the severity of caseloads evidenced in the case-control study.

[Judicial aspects of treatment of incompetent psychiatric patients who categorically refuse treatment]. / La judiciarisation du traitement du malade psychiatrique inapte qui refuse catégoriquement de consentir.

Psychiatrists in particular face a clinical, legal and social dilemma in treating their patients who are likely to categorically oppose treatment. This article illustrates this dilemma in the context of Quebec's Bill 145, resulting in the care of psychiatric patients being increasingly referred to the courts. After presenting this legislation and a case, the authors illustrate the impact of this legislation in light of their own experience and similar legislation in the United States. The mechanisms proposed by Bill 145 have proved costly in several respects as well as cumbersome and ineffective. The authors propose the establishment of an administrative tribunal as an alternative to the current recourse to the courts.

Vision of the stylus in a manual aiming task: the effects of practice.

Nearly a decade ago, Carlton (1981) showed that in a manual aiming task, vision of the ongoing stylus led to a better accuracy than when that source of information was not available. However, Elliott (1988) recently failed to replicate that finding and, rather, showed that being able to see an ongoing stylus did not result in a significant improvement of accuracy over a conventional no-vision condition. In the experiment to be reported here, we, on the one hand, replicated Elliott's results for the low level of practice condition (15 acquisition trials). On the other hand, the results obtained after moderate practice (150 acquisition trials) supported Carlton's earlier conclusion. These results therefore indicate that after sufficient practice one is able to use effectively the information provided by the ongoing stylus to help control his/her movement. This conclusion was further substantiated by the results obtained in a transfer task. Collectively, the results gave added support to a specificity of learning hypothesis (Proteau, Marteniuk, Girouard, & Dugas, 1987; Proteau, Marteniuk, & Lévesque, 1990).

[Analysis of non-optimal behavior in a dichotomous choice situation]. / Analyse des comportements non-optimaux en situation de choix dichotomique.

Proteau and Girouard (1987) have recently proposed a model to explain the decisional process that takes place in a two-choice reaction time situation. Although the model was well supported by the experimental data reported by these authors, a few unexplained results were observed and hypotheses were suggested to account for them. The goal of the present experiment was, first, to replicate the results presented by Proteau and Girouard (1987) to support their model. Our second goal was to determine if the unexpected results reported by these authors can be linked to some particular conditions occurring in the normal course of an experiment. The results obtained in the present experiment totally supported the proposed model. Furthermore, a detailed analysis of the circumstances under which unexpected results occurred did not permit the identification of any particular conditions favoring their occurrence. In conclusion, the proposed model, although reliable for about 95% of the trials, is still imperfect.

Bluefish-associated scombroid poisoning. An example of the expanding spectrum of food poisoning from seafood.

Five persons who attended a medical conference developed symptoms suggestive of an intoxication after a common meal. Although the symptoms were recognized as typical of scombroid poisoning, no fish of the Scrombridae family had been served. However, food histories implicated bluefish (Pomatomus saltatrix). The initially frozen bluefish had been improperly handled in storage and thawing. Elevated levels of histamine, putrescine, and cadaverine were detected in uncooked samples. This outbreak emphasizes that scombroid-type poisoning (1) can be caused by nonscombroid fish such as bluefish, (2) is probably more common than currently recognized, and (3) may become even more widespread as fish become a larger part of our diet. Physicians who work in conjunction with public health officials can help prevent additional cases and outbreaks.

[Rapid response of a disorder to the addition of lithium carbonate: panic resistant to tricyclic antidepressants]. / Réponse rapide à l'addition du carbonate de lithium d'un trouble: panique résistant aux antidépresseurs tricycliques.

There is evidence that panic disorder and major depression might share some common neurobiological factors. This would be consistent with the fact that most antidepressant drugs are effective in preventing panic attacks. This is a case report of a 40 year old woman who was suffering from a panic disorder. Following the discontinuation of a long-term lorazepam treatment, she developed severe depressive symptoms. The depressive syndrome improved rapidly with amitriptyline (150 mg/day), but the panic attacks persisted. Twelve weeks later, amitriptyline was replaced by clomipramine (150 mg/day), the dosage of which was increased to 225 mg/day three weeks later. The patient remained anxious with no resolution of her panic attacks. Two weeks later, lithium carbonate (900 mg/day) was added to clomipramine. Sixty hours later, a dramatic improvement was observed. The lithium plasma level was 0.8 mEq/L. Because of some tremors, lithium was discontinued five days later. Within four days, the anxiety as well as the panic attacks reappeared. Lithium carbonate (600 mg/day) was then resumed. Forty-eight hours later, the patient was showing a clinical improvement similar to that observed following the first addition of lithium. She remained symptom free with the maintenance of the drug combination. To date, several reports have confirmed the beneficial effect of adding lithium to a tricyclic antidepressant drug in resistant major depression. However, we believe that the present case report is the first one documenting the augmentation of a tricyclic antidepressant drug by lithium in a patient suffering from a panic disorder.