A morphometric study on the longitudinal and lateral symmetry of the sural nerve in mature and aging female rats

Aging affects peripheral nerve function and regeneration in experimental models but few literature reports deal with animals aged more than one year. We investigated morphological and morphometric aspects of the sural nerve in aging rats. Female Wistar rats 360, 640 and 720 days old were killed, proximal and distal segments of the right and left sural nerves were prepared for light microscopy and computerized morphometry. No morphometric differences between proximal and distal segments or between right and left sides at the same levels were found in all experimental groups. No increase in fiber and axon sizes was observed from 360 to 720 days. Likewise, no difference in total myelinated fiber number was observed between groups. Myelinated fiber population distribution was bimodal, being the 720-days old animals` distribution shifted to the left, indicating a reduction of the fiber diameters. The 9 ratio distribution of the 720-days old animals` myelinated fiber was also shifted to the left, which suggests axonal atrophy. Morphological alterations due to aging were observed, mainly related to the myelin sheath, which suggests demyelination. Large fibers were more affected than the smaller ones. Axon abnormalities were not as common or as obvious as the myelin changes and Wallerian degeneration was rarely found. These alterations were observed in all experimental groups but were much less pronounced in rats 360 days old and their severity increased with aging. in conclusion, the present study indicates that the aging neuropathy present in the sural nerve of female rats is both axonal and demyelinating. (C) 2008 Elsevier B.V. All rights reserved.

The teaching of History meets its past: memories of teaching staff during the civil-military dictatorship

The civil-military dictatorship, which took power in 1964, influenced the daily activities of schools and teachers. Many transformations occurred during this period, including the new legislation enacted under Law 5692/71 and changes which occurred due to the vigilance which teachers felt when working. The memories analyzed here of teachers from public schools in Sao Paulo show different perceptions of this surveillance, involving various forms of acceptance or resistance. The purpose of this article is to show that although there was no direct repression of schools, unlike in the universities, teachers at the elementary school also felt constrained and this can be seen in their educational practices and teaching concepts.

Pharmacokinetic software for the health sciences - Choosing the right package for teaching purposes

Computer assisted learning has an important role in the teaching of pharmacokinetics to health sciences students because it transfers the emphasis from the purely mathematical domain to an 'experiential' domain in which graphical and symbolic representations of actions and their consequences form the major focus for learning. Basic pharmacokinetic concepts can be taught by experimenting with the interplay between dose and dosage interval with drug absorption (e.g. absorption rate, bioavailability), drug distribution (e.g. volume of distribution, protein binding) and drug elimination (e.g. clearance) on drug concentrations using library ('canned') pharmacokinetic models. Such 'what if' approaches are found in calculator-simulators such as PharmaCalc, Practical Pharmacokinetics and PK Solutions. Others such as SAAM II, ModelMaker, and Stella represent the 'systems dynamics' genre, which requires the user to conceptualise a problem and formulate the model on-screen using symbols, icons, and directional arrows. The choice of software should be determined by the aims of the subject/course, the experience and background of the students in pharmacokinetics, and institutional factors including price and networking capabilities of the package(s). Enhanced learning may result if the computer teaching of pharmacokinetics is supported by tutorials, especially where the techniques are applied to solving problems in which the link with healthcare practices is clearly established.

An evidence-based medicine fellowship in a children's teaching hospital

This paper reports the introduction of an evidence-based medicine fellowship in a children’s teaching hospital. The results are presented of a self-reported ‘evidence-based medicine’ questionnaire, the clinical questions requested through the information retrieval service are outlined and the results of an information retrieval service user questionnaire are reported. It was confirmed that clinicians have frequent clinical questions that mostly remain unanswered. The responses to four questions with ‘good quality’ evidence-based answers were reviewed and suggest that at least one-quarter of doctors were not aware of the current best available evidence. There was a high level of satisfaction with the information retrieval service; 19% of users indicated that the information changed their clinical practice and 73% indicated that the information confirmed their clinical practice. The introduction of an evidence-based medicine fellowship is one method of disseminating the practice of evidence-based medicine in a tertiary children’s hospital.