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Biomedical subjects

M Perlmutter

Publications and source records attributed to M Perlmutter.

15 recordsLinked to original sources
PubMed1990

Synthesis of 4-[18F]fluoro-L-m-tyrosine: a model analog for the in vivo assessment of central dopaminergic function.

4-[18F]Fluoro-L-m-tyrosine (6), a new analog of L-dopa for probing the presynaptic dopaminergic system by positron emission tomography has been synthesized in good radiochemical yields via the regioselective fluorodemercuration of the 4-mercurio derivatives 4a and 4b with 18F-labeled acetylhypofluorite. The chemical, radiochemical and enantiomeric purities were determined to be greater than 99%. The key step in the synthesis of the precursors 4 was the mercuration of the protected L-m-tyrosine 3. The position of mercuration on the aromatic ring was gleaned from the 13C-NMR spectral data. The non-radiolabeled counterpart of 6 was also synthesized. Structural analyses of all these compounds were carried out by 1H-, 13C-, 19F-NMR and mass spectroscopy.

Fluorine Radioisotopes↗
PubMed1990

Remote, semiautomated production of 6-[18F]fluoro-L-dopa for human studies with PET.

Regioselective radiofluorodemercuration of the 6-mercurio derivative 5 with [18F]acetylhypofluorite afforded, after acidic hydrolysis, 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine (6-FD, 1) with a radiochemical yield of 11% (decay corrected and based on the total amount of [18F]F2 recovered from the target). 6-FD was obtained with a chemical and radiochemical purity of greater than 99% and with a level of mercury in the final preparation of less than 20 ppb. Utilization of a remote, semiautomated production system, resulted in the preparation of a sterile, pyrogen-free product suitable for human injection after a synthesis time of 50 min.

Dihydroxyphenylalanine↗
PubMed1990

Relationships between self-reported physical and mental health and intelligence performance across adulthood.

One hundred and twenty-seven adults between 20 and 90 years of age were tested on the Wechsler Adult Intelligence Scale for their digit span memory (forward and backward), fluid intelligence (block design and digit symbol), and crystallized intelligence (vocabulary and information), as well as assessed for self-reported health (Cornell Medical Index, Zung Depression Scale, health habits, and self-ratings of physical and mental health). As expected, across the entire age range there was no correlation between age and digit span memory (r = .03), a strong negative correlation between age and fluid intelligence (r = -.78), and a modest positive correlation between age and crystallized intelligence (r = .27). In addition, older adults reported more physical (r = .36) and mental (r = .32) health problems than did younger adults. Of special interest was the finding that both self-reported physical and mental health accounted for significant variance in intelligence performance, particularly in older adults. Moreover, self-reported health accounted for a considerable portion of observed variance, even when age differences in self-reported health were statistically controlled.

Adult↗
PubMed1988

Age differences in adults' scene memory: knowledge and strategy interactions.

Three studies explored young and old adults' use of knowledge to support memory performance. Subjects viewed slides of familiar scenes containing high expectancy and low expectancy items and received free recall (Experiments 1, 2, and 3), cued recall (Experiments 1 and 2), and recognition (Experiments 1 and 2) tests. In Experiment 1 encoding intentionality was varied between subjects. Young adults performed better than old adults on all tests, but on all tests, both age groups produced a similar pattern of better memory of high expectancy than low expectancy items and showed an encoding intentionality effect for low expectancy items. In Experiments 2 and 3 all subjects were told to intentionally encode only one item from each scene; the remaining items could be encoded incidentally. Young adults performed better than old adults, although again, the pattern of performance of the two age groups was similar. High expectancy and low expectancy intentional items were recalled equally well, but high expectancy incidental items were recalled better than low expectancy incidental items. Low expectancy intentional items were recognized better than high expectancy intentional items, but incidental high expectancy items were recognized better than incidental low expectancy items. It was concluded that young and old adults use their knowledge in similar ways to guide scene memory. The effects of item expectancy and item intentionality were interpreted within Hasher & Zacks' (2) model of automatic and effortful processes.

Adolescent↗
PubMed1987

Aging and memory.

Although some age-related decline in memory probably occurs, most memory changes that result from normal aging are not as extensive within individuals or as representative within the population as previously had been believed (Zarit et al., 1981). Still, when older adults become aware of memory problems, they typically become quite alarmed (see Poon et al., 1980). One reason for this alarm is that memory loss has been found to be a reliable early sign of organic brain disease. Despite the sadness and severity of problems experienced by these patients and their families, the actual incidence of organic brain disease in older adults remains quite low. Unfortunately, it is possible that older adults' concern about less significant memory loss may compound or magnify problems that do exist. Therefore, when working with relatively healthy older adults, it is important first to consider possible transitory, nonmemory factors that could be contributing to memory problems and then to provide the clients with some perspective on their memory failures.

Aged↗
PubMed1987

A life-span study of the interaction of selectivity and knowledge in memory.

Preschool children, young adults, and old adults viewed a series of familiar scenes and were asked to remember 1 item from each. The incidental memory of both children and old adults was less accurate than that of young adults. The result for children contrasts with the typical result of selective memorization research. Memory for high-expectancy items exceeded that for low-expectancy items by a greater margin when items were incidental, suggesting that even preschool children activate scene schemas during encoding. Only the young adults, however, showed the predicted tendency to recognize low-expectancy items better than high-expectancy items when items were intentional. These results may be reconcilable if some, but not all, schema-mediated encoding effects on memory depend on strategic encoding.

Adolescent↗
PubMed1986

Cognitive and social functioning across adulthood: age or student status differences?

Younger adult students between 19 and 24 years of age (M = 21.3 years), older adult students between 61 and 76 years of age (M = 67.9 years), and older adult nonstudents between 62 and 76 years of age (M = 68.5 years) were assessed for health (self-ratings of physical and mental health), social functioning (self-ratings of physical and mental activity, perceived role activity level, perceived roles, locus of control, and age-norm expectations), and cognitive functioning (Wechsler Adult Intelligence Scale-Revised vocabulary and block design, and paired associate memory). Age differences were observed in self-ratings of health, social roles, intellectual performance, and memory. No student status differences were observed. The results are discussed in terms of plasticity of intellectual function and characteristics of student status in later adulthood.

Adult↗
PubMed1979

Age differences in the consistency of adults' associative responses.

Younger (mean age = 20) and older (mean age = 63) adults were asked to produce free associations to the same list of 24 verbal stimuli on each of four trials. Older adults tended to produce less common associations and their associations were less consistent across trials. Possible relationships between older adults' inconsistency in processing and their (a) poorer memory performance and (b) slower reaction times were discussed.

Adult↗
PubMed1979

Age differences in adults' free recall, cued recall, and recognition.

Adults in their twenties and sixties were tested for free recall, cued recall, and recognition of words that they had studied in an intentional memory task or generated associations to in an incidental orienting task. Significant age-related declines in performances on intentional items were observed regardless of type of memory test. Significant age-related declines in performance on incidental items were also observed on free and cued recall tests; however, age differences on incidental items were attenuated on cued recall tests, and they were eliminated on recognition tests. In addition, while younger subjects profited more from retrieval cues that were associations they had themselves generated than from retrieval cues that were normed common associations, older subjects made comparable use of these two cue types.

Adult↗
PubMed1975

Young children's coding and storage of visual and verbal material.

36 preschool children (mean age 4.2 years) were each tested on 3 recognition memory lists differing in test mode (visual only, verbal only, combined visual-verbal). For one-third of the children, original list presentation was visual only, for another third, presentation was verbal only, and the final third received combined visual-verbal presentation. The subjects generally performed at a high level of correct responding. Verbal-only presentation resulted in less correct recognition than did either visual-only or combined visual-verbal presentation. However, because performances under both visual-only and combined visual-verbal presentation were statistically comparable, and a high level of spontaneous labeling was observed when items were presented only visually, a dual-processing conceptualization of memory in 4-year-olds was suggested.

Acoustic Stimulation↗