Age differences in adults' self-reports of memory ability: it depends on how and what you ask

Self-reports of memory abilities and skills were obtained from fifty younger (M = 20.2) and fifty older (M = 68.7) adults. General rating questions (e.g., How good do you feel your memory is?) and specific questions about memory for certain types of content (e.g., people's names) were included. Consistent age-related decrements were found only for general questions, especially those assessing perceived changes over time. Less consistent differences were found for specific questions. Results were interpreted in terms of implications for assessing self-reported memory ability, and in terms of their meaning for research on the relationship between self-reported and actual memory ability.     

Immunohistochemical localization of prostaglandin H synthase isoenzyme proteins in the gingival tissue of patients with periodontitis

Prostaglandins are inflammatory mediators that are believed to play an important role in the pathophysiology of periodontal disease. Prostaglandin H synthase (PGHS, EC 1.14.99.1) is the rate-limiting enzyme in prostaglandin biosynthesis. The enzyme exists as two separately encoded isoforms. PGHS-1 which is constitutively expressed and PGHS-2 which is induced by inflammatory stimuli. This is the first report describing the expression of the isoenzymes in gingival tissue from patients diagnosed with adult periodontitis. Tissue was fixed in an alcohol-based fixative and embedded in paraffin. Methods were developed using immunohistochemical controls, such that embedded sections could be processed and stained using isoform-specific antibodies and a peroxidase-antiperoxidase immunohistochemistry technique. Along with populations of mononuclear inflammatory cells, endothelial cells and fibroblasts, the gingival epithelial cell layer appears to be a rich and important source of prostaglandin production within the periodontium of patients with periodontitis as detected by this newly developed immunohistochemical staining technique for PGHS-1 and PGHS-2.     

Mode and speed specificity of eccentric and concentric exercise training

This research was supported by a Duke University Research Council Grant. The purpose of this study was to examine mode and speed specificity of strength training by comparing concentric and eccentric isokinetic exercise of the quadriceps. Forty-eight healthy men (mean age = 23.9 years) were randomly assigned to one of three groups: concentric training (C), eccentric training (E), or control (K). Average force (in Newtons) of 3 concentric and of 3 eccentric quadriceps contractions on the KIN-COM(R) dynamometer at 60, 120, and 180 degrees /sec was evaluated prior to and following a 6 week period during which only the C and E groups trained. Training sessions (3/week) included 4 submaximal and 1 maximal warm-up followed by 10 maximal effort isokinetic contractions of the quadriceps at 120 degrees /sec for each leg. Group C subjects trained concentrically only while Group E subjects trained eccentrically only. A t-test for independent means showed no significant right/left differences. ANOVA and Scheffe's F-tests were then used to assess the differences in training effects among the 3 groups for the left leg only. Results showed that although Group C increased slightly in both concentric and eccentric force at all speeds, the gains were significant only for concentric force at 180 degrees /sec. Group E showed significant gains (p < 0.05) in eccentric force at all speeds but not in concentric force. The K group had no significant change in concentric or eccentric force at any speed. We conclude that the eccentric mode of isokinetic exercise has highly specific strength training effects while the concentric mode has less specific training effects. In addition, speed of exercise does not appear to have specific training effects. J Orthop Sports Phys Ther 1989;11(2):70-75.     

Effectiveness of a brief workshop designed to improve teaching performance at the University of Alberta.

PURPOSE: To determine whether a two-day teaching enhancement workshop at the University of Alberta improved participants' teaching performance as rated by students. METHOD: Workshop participants (academic staff or residents) were asked to assess the value of the workshop. In addition, students were asked to rate instructors' teaching abilities before and after the instructors participated in the workshops, by completing a five-statement questionnaire routinely used to assess instruction at the University of Alberta. For control purposes, ratings were also obtained for a group of instructors who had not taken the workshop, over a similar time period. The authors used data from 1993-2002. RESULTS: The participants uniformly regarded the workshops as helpful. Both faculty and residents regarded the short teaching exercise as the most important component of the program. Of the instructional sections, the presentations on objectives and on structure (set, body, closure) were rated most highly by both groups. The students' mean ratings for the instructors after the workshop were significantly increased, while ratings for those who had not taken the workshop were unchanged CONCLUSION: Short teaching-enhancement workshops are regarded by the participants as helpful in improving their instructional skills. This view is supported by a significant increase in students' ratings of the instructors after they had taken the workshop.     

The effect of varying impact energy on diffuse axonal injury in the rat brain: a preliminary study

Diffuse axonal injury (DAI) is seen as widespread damage in the white matter of brain characterized by morphological changes to axons throughout the brain and brain stem. The current study attempted to investigate the effect of increasing impact energy on the presence and severity of DAI in corpus callosum (CC). DAI was induced in adult male Sprague-Dawley rats using an injury model adapted from Marmarou et al. in 1994. A 450-g cylindrical brass weight was dropped from three different heights (2.0 m, 1.5 m and 1.0 m) on to a metal helmet affixed to the skull of the rats. In the sham group, rats underwent a surgical procedure with no impact. After a 24-h survival period the animals were transcardially perfused. The brain was removed and the cerebral hemispheres were sectioned with a vibrotome and stained by silver impregnation technique. The CC of all the impacted rats showed DAI in the form of beaded axons, retraction balls and vacuole-like enlargements. The axonal injury was most severe in the 2-m group, while mildest in the 1-m group. In the sham group, axons appeared to be normal. This study demonstrates evidence of graded DAI depending on the impact energy. Such data is useful for mathematical modeling of axonal injury in rat brain using the same impact parameters and potential determination of injury thresholds for neural trauma. Electronic Publication     

Microvascular function in skin windows.

The dermal microvasculature is an integral component of skin windows. However, in spite of the obvious dependence of the skin window model on vascular function, its almost exclusive application has been the study of leukocyte function and recovery of the cellular components of inflammatory exudates. In the studies reported here, skin window chambers were employed for assessment of function of the underlying microvasculature in rats given intravenous infusions of Evans blue dye or colloidal carbon. Increased vascular permeability was documented by photometric measurement of Evans blue dye, and vascular labeling of dermal vessels with colloidal carbon was assessed histologically. Zymosan-activated serum elicited accumulation of both leukocytes and Evans blue dye in chamber fluid overlying skin windows, confirming the responsiveness of the preparations. With serotonin as a model vasoactive substance, both increased vascular permeability and vascular labeling were directly related to serotonin concentration in the chamber fluid. It is estimated that plasma exudates were distributed as approximately 10% in the fluid and 90% in the dermis. Finally, serotonin-induced exudates recovered from the 0.3-ml chambers were estimated to be up to 3 microliter of plasma based on Evans blue dye measurement or up to 70 micrograms of protein based on Lowry assay. Thus, soluble components of skin window exudates were recovered for examination, and the dermal microvasculature was shown to be an important functional component of the skin window model that was directly accessible for study.     

The anterior bronchus sign: a new clue to hilar abnormality

One hundred normal posteroanterior chest radiographs were reviewed to determine the frequency of appearance and characteristics of the anterior segmental bronchi of the upper lobes. The bronchus was visible as a sharp circle on the right in 45% of normals, and on the left in 50%. In 90% of normals, there is less than 3 mm of tissue lateral to the bronchus. In 10% of normals, pulmonary vessels may cause 3-5 mm of tissue lateral to the bronchus. Four cases of bronchogenic carcinoma were found to have more than 5 mm of tissue lateral to the bronchus. The presence of more than 5 mm of tissue lateral to the anterior segmental bronchus is termed the "anterior bronchus sign" and is a helpful clue to recognizing hilar region abnormality.