Serum neurotrophins--a study on the time course and influencing factors in a large old age sample.

The neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are important mediators of brain and neuronal development, the maintenance of homeostatic conditions in the adult nervous system, and the complex interplay of central and peripheral physiological and pathophysiological factors. To date there are few studies examining blood concentrations of neurotrophic factors in large samples of healthy and diseased individuals and no published study specifically addresses peripheral BDNF and NGF levels in late life. Using improved highly sensitive and specific fluorometric two-site enzyme-linked immunosorbent assays we examined BDNF (n=465) and NGF (n=175) serum levels in a large cohort of elderly individuals (age range: 70-103 years). Neither BDNF nor NGF serum levels proved to be normally distributed, indicating that previously published studies with small sample sizes using parametric testing may be misleading. A significant correlation was found between BDNF and platelet count (r=0.344, p<0.01), age and BDNF protein (r=-0.101, p=0.029) and BDNF and NGF serum levels (r=0.152, p=0.04). No other major influencing factors were found including gender, depression, and dementia.

www.tnt-radiology.de: Teach and be taught radiology: implementation of a web-based training program based on user preferences as determined by survery.

RATIONALE AND OBJECTIVES: To create a Web-based training program addressing the needs of a large, heterogeneous audience of users. MATERIALS AND METHODS: We defined our target group as consisting of medical professionals who teach radiology, or who, by their own perception, would benefit from improving their radiologic image interpretation skills. We interviewed 483 members of this group, eliciting their preferences with regard to layout, interactivity, contents, and other categories (11 in total). Considering majority preferences as recommendations and using the help of a special interest group of medical students, we assembled 500 teaching cases over a 1-year period into an interactive training program and made it available on the World Wide Web. RESULTS: Important preferences expressed by majorities of interviewees were: high levels of interactivity, clear layout, intuitive usability, short page load times, permissibility of saving content locally, cost-free access, consideration of user input in the site development. To our knowledge, our web program TNT-Radiology, accessible at , is the first to implement all of these recommendations simultaneously. CONCLUSIONS: We have created a Web-based program usable for teaching and learning radiologic image interpretation that meets the needs of a heterogeneous target audience to an unprecedented extent.

Measurement of nerve growth factor serum concentration in a psychologically stressful situation in men.

Psychologically stressful events have been reported to elevate nerve growth factor (NGF) serum concentrations. NGF and cortisol serum concentrations were measured in 20 healthy male volunteers before (3 p.m.) and after (5 p.m.) an academic oral presentation and on a control day. Cortisol showed a significant overall change (p=0.001), i.e. cortisol serum concentrations were increased on the lecture day at 3 p.m. (p=0.007; 155%) and at 5 p.m. (p=0.001; 175%) as compared with the control day. In contrast to cortisol no significant differences among the four serum NGF measurements was detected (Chi-quadrat 2.94, df=3, p=0.401), i.e. the NGF serum concentrations remained unchanged on the lecture day at 3 p.m. (p=0.279) and at 5 p.m. (p=0.627) as compared with the control day. We conclude that NGF serum levels do not change during acute stress, at least after this type of stressor.

Serum nerve growth factor concentration and its role in the preclinical stage of dementia.

OBJECTIVE: Nerve growth factor is important for the development and function of the cholinergic basal forebrain. The authors examined the hypothesis that the concentration of nerve growth factor is lower than normal in the preclinical phase of neurodegenerative dementia, especially Alzheimer's disease. METHOD: The serum nerve growth factor concentration of subjects from the Berlin Aging Study and the Berlin Memory Clinic who later developed Alzheimer's disease were compared with those of subjects who were free of dementia and subjects who were already suffering from Alzheimer's disease. RESULTS: There were 17 subjects in each group, matched for age and sex. The three groups differed in log-10-transformed mean nerve growth factor concentrations: 1.62 (SD=0.59) for the healthy comparison subjects, 0.92 (SD=0.30) for the subjects with preclinical dementia, and 1.44 (SD=0.61) for the subjects with Alzheimer's disease. CONCLUSIONS: These results support the hypothesis of disturbed nerve growth factor regulation in the serum of patients with preclinical Alzheimer's disease. Mechanisms by which these disturbances appear are unclear, but they may reflect the situation in the preclinical Alzheimer's disease brain.