R. I. PFEFFER

Two measures of social function designed for community studies of normal aging and mild senile dementia were evaluated in 195 older adults who underwent neurological, cognitive, and affective assessment. An examining and a reviewing neurologist and a neurologically trained nurse independently rated each on a scale of functional capacity. Interrater reliability was high (examining Vs. reviewing neurologist, r = .97; examining neurologist Vs. Nurse, tau b = .802; p < .001 for both comparisons). Estimates Correlated well with an established measure of social function and with results of cognitive tests. Alternate Informants Evaluated participants on the functional activities questionnaire and the Instrumental Activities of Daily Living Scale. The Functional Activities Questionnaire was superior to the Instrumental Activities of Daily Living Scale in discriminating among functional levels and in predicting neurologist ratings and cognitive scores. Used alone as a diagnostic tool, the Functional Activities Questionnaire was more sensitive than the Instrumental Activities of Daily Living Scale (.85 vs. .57) and almost as specific (.81 Vs. .92) in distinguishing between normal and demented individuals.

In a white, predominantly middle class southern California retirement community, 817 adults aged 65-99 years were evaluated in 1980-1982 in a study designed to assess prevalence of early Alzheimer-type senile dementia. Based on 162 neurologically diagnosed cases, the age- and sex-adjusted prevalence of Alzheimer's disease in the target population was 15.3% (95% confidence interval = 13.0-17.5) among persons aged 65+ years and 35.8% among persons aged 80+ years. Age-adjusted correction for false negatives not detected by a screening procedure yields an estimated prevalence of 16.4% in persons aged 65+ years. Validity of the diagnostic approach was confirmed by a follow-up study. These rates far exceed past prevalence estimates for this disease. Since prevalence of mid- or later stages of Alzheimer's disease may have been underestimated, the high rates in this study may reflect a considerable community burden of early disease. Observed prevalence of Alzheimer-type senile dementia was higher among men than women after adjustment for age, 19.1% and 13.1%, respectively. The female predominance reported in many past clinical surveys may be peculiar to late disease and reflect care-seeking and care-utilization behaviors, rather than differences in incidence.

Social navigation in a community of practice (CoP) is an approach of locating information through increased social awareness. Designing support for social navigation requires precise knowledge about the users’ needs and wishes so as to meet user participatory design methodology. User requirement definition on social navigation is, however, difficult to elicit. On the one hand, without the context of the CoP, it is hard to collect the user requirements on navigation, especially when the concept of virtual community is new to the target user group. On the other hand, to set up such a virtual community, preliminary studies on social navigation is however necessary. This paper presents the experiences how we dealt with such a chicken and egg problem. Different approaches were used: performing a theoretical study, administering an online questionnaire, observing on an existing virtual society, analyzing similar systems, prototyping, and conducting an expert walk-through.

Monoamine oxidase inhibitors, indirectly acting sympathomimetic amines, reserpine and bretylium, which possess no direct inhibitory effect on tyrosine hydroxylase, inhibit tyrosine hydroxylase in intact, adrenergically innervated tissue, presumably by increasing the concentration of free intraneuronal norepinephrine. The increased free norepinephrine in the axoplasm inhibits tyrosine hydroxylase by competitive antagonism with the pteridine cofactor. The effects of monoamine oxidase inhibitors, indirectly acting sympathomimetic amines, and bretylium on tyrosine hydroxylase can be antagonized by addition of excess pteridine cofactor to the medium. Stimulation of the hypogastric nerve of the isolated vas deferens preparation of the guinea pig is associated with increased tyrosine hydroxylase activity both during stimulation and in the immediate poststimulation period. The poststimulation increase in norepinephrine synthesis is not antagonized by norepinephrine. The increase in tyrosine hydroxylase activity demonstrable during nerve stimulation is partially antagonized by norepinephrine, but is not reversed by the addition of excess reduced pteridine cofactor to the medium.