Cognitive arithmetic: comparison of operations

Adults' performance of simple arithmetic calculations (addition, multiplication, and numerical comparison) was examined to test predictions of digital (counting), analog, and network models. Although all of these models have been supported by studies of mental addition, each leads to a different prediction concerning relations between the times required for addition, multiplication, and numerical comparison. Pairs of single-digit integers were presented and reaction times (RTs) for adding, multiplying, and comparing the stimuli were collected. A high correlation between RT for addition and multiplication of the same digits was obtained. This result is consistent with a network model, but presents difficulties for both analog and counting models. A "ties" effect of no increase in RT with increases in problem size for doubles such as 2 + 2 has been found in previous studies of addition using verification procedures, but was not found with the production task employed in the present study. Instead, a different kind of ties effect was found. Reaction time for both addition and multiplication of ties increased more slowly with problem size than did RT for non-tie problems. This ties effect, and the finding that probability of making errors contributes independently of problem size to RT support a distinction between location and accessibility of information in a network.

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.

Forgetting and use of memory aids in 20 to 70 year olds everyday life

In order to examine age differences in everyday memory experiences, twelve younger (mean age = 28) and twelve older (mean age = 59) adults kept diaries of their experiences of memory failures and use of memory aids. There was a general increase with age in the absolute number of memory failures, upset ratings about memory failures, and frequency of memory aid use. There were no age differences in the relative frequency of particular types of memory failures or memory aids that were used. The results suggested that older adults experience more memory failures and are more concerned about memory failures than younger adults, but that they attempt to deal with this problem by increased use of memory aids.

Spatial and temporal memory in 20 to 60 year olds

Younger (mean age = 20 years) and older (mean age = 64 years) adults were tested on spatial and temporal memory tasks. No age difference was observed on the temporal task but older adults performed worse than younger adults on the spatial task. The absence of an age-related decline in performance on the temporal task is counter to most previous developmental research on adults' memory. This finding indicates that normal aging is not associated with poor encoding or retention of all types of information. The presence of an age-related decline in performance on the spatial task is consistent with most research on memory aging. Moreover, this finding indicates that aging affects retention of some types of information often assumed to be encoded automatically.

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.

Sialylation of 3-methylcholanthrene-induced fibrosarcoma determines antitumor immune responses during immunoediting

Sialylation of tumor cells is involved in various aspects of their malignancy (proliferation, motility, invasion, and metastasis); however, its effect on the process of immunoediting that affects tumor cell immunogenicity has not been studied. We have shown that in mice with impaired immunoediting, such as in IL-1α(-/-) and IFNγ(-/-) mice, 3-methylcholanthrene-induced fibrosarcoma cells are immunogenic and concomitantly bear low levels of surface sialylation, whereas tumor cells derived from wild type mice are nonimmunogenic and bear higher levels of surface sialylation. To study immune mechanisms whose interaction with tumor cells involves surface sialic acid residues, we used highly sialylated 3-methylcholanthrene-induced nonimmunogenic fibrosarcoma cell lines from wild type mice, which were treated with sialidase to mimic immunogenic tumor cell variants. In vivo and in vitro experiments revealed that desialylation of tumor cells reduced their growth and induced cytotoxicity by NK cells. Moreover, sialidase-treated tumor cells better activated NK cells for IFN-γ secretion. The NKG2D-activating receptor on NK cells was shown to be involved in interactions with desialylated ligands on tumor cells, the nature of which is still not known. Thus, the degree of sialylation on tumor cells, which is selected during the process of immunoediting, has possibly evolved as an important mechanism of tumor cells with low intrinsic immunogenicity or select for tumor cells that can evade the immune system or subvert its function. When immunoediting is impaired, such as in IFN-γ(-/-) and IL-1α(-/-) mice, the overt tumor consists of desialylayed tumor cells that interact better with immunosurveillance cells.

Adult age-group differences in recall for the literal and interpretive meanings of narrative text

This study examined age differences in recall for the literal and interpretive meanings of narrative text. Following presentation of one of two stories rich in both literal and interpretive content, younger (mean age = 19.2 years) and older (mean age = 72.2 years) adults were asked to retell and to interpret the story. Response task order was counterbalanced across participants. When asked to retell a story as close to the original as possible, the younger adults recalled more of the literal propositional content than did the older adults in the retell-first, although not in the interpret-first, condition. In addition, both older and younger adults recalled more of the main ideas (gist) relative to the details. When asked to interpret the same story, more older than younger adults produced deep and synthetic representations of the story's interpretive meanings. In addition, there was a clear preference among the older age group for deep-synthetic responding. Although more younger than older adults produced analytic interpretations, within the younger group there was no clear preference for either an analytic or a deep-synthetic style.

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.

Orphanin FQ/nociceptin analgesia in the rat

The heptadecapeptide orphanin FQ or nociceptin (OFQ/N), the endogenous ligand for the orphan opioid receptor, has a complex pharmacology in mice, eliciting either an anti-opioid/hyperalgesic action or analgesia depending upon the dose and testing paradigm. Unlike mice, orphanin FQ/nociceptin fails to elicit hyperalgesia in the rat following intracerebroventricular injection. Both OFQ/N and a truncated version, OFQ/N(1-11), produce a robust analgesic response. OFQ/N analgesia is readily antagonized by the opioid antagonists naloxone or diprenorphine, despite their very poor affinity for the cloned orphan opioid receptor. Antisense studies revealed that probes targeting the second and third coding exon of the orphan clone significantly attenuate OFQ/N analgesia, while the exon 1 probe was inactive. These results indicate that OFQ/N elicits a naloxone-sensitive analgesia in rats similar to that previously reported in mice.

Future time perspective and life events across adulthood

Age differences in future time perspective and the relations between future time perspective, locus of control, and past and anticipated future life events were examined in younger (ages 20 to 37) and older (ages 60 to 81) men and women. There were neither age nor gender differences in the time period participants reported thinking of most frequently. Participants reported thinking about the next few months more frequently than about other future time periods, which ranged from the next few days to many years. However, younger participants also reported thinking frequently about more distant time periods, whereas older subjects did not. Anticipation of discontinuous future events, control of impending events, and positive past events accounted for some age differences found in thinking about distant future time periods. No systematic gender differences were found.

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.

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.

Cognitive arithmetic: comparison of operations

Adults' performance of simple arithmetic calculations (addition, multiplication, and numerical comparison) was examined to test predictions of digital (counting), analog, and network models. Although all of these models have been supported by studies of mental addition, each leads to a different prediction concerning relations between the times required for addition, multiplication, and numerical comparison. Pairs of single-digit integers were presented and reaction times (RTs) for adding, multiplying, and comparing the stimuli were collected. A high correlation between RT for addition and multiplication of the same digits was obtained. This result is consistent with a network model, but presents difficulties for both analog and counting models. A "ties" effect of no increase in RT with increases in problem size for doubles such as 2 + 2 has been found in previous studies of addition using verification procedures, but was not found with the production task employed in the present study. Instead, a different kind of ties effect was found. Reaction time for both addition and multiplication of ties increased more slowly with problem size than did RT for non-tie problems. This ties effect, and the finding that probability of making errors contributes independently of problem size to RT support a distinction between location and accessibility of information in a network.

The Charleston policy on cocaine use during pregnancy: a cautionary tale

The conflict between pregnant women freely using cocaine and the well-being of fetuses presents a difficult social problem. Since 1985, at least 200 women, in thirty states, have been criminally prosecuted for using illicit drugs or alcohol during pregnancy. Such policies enjoy considerable public and political support. Nonetheless, treatment programs that include referral to law enforcement officials raise serious ethical and legal issues for hospitals and health care providers. In this paper, we assess the development of one medical university's controversial treatment program for pregnant women addicted to cocaine.

In October 1989, the Medical University of South Carolina (MUSC) instituted a new program, called the Interagency Policy on Management of Substance Abuse During Pregnancy (Interagency Policy), designed “to ensure appropriate management of patients abusing illegal drugs during pregnancy.” This program required some pregnant women to seek drug counseling and prenatal care under the threat of criminal sanctions.

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.

Memory of historical events

Younger (mean age = 20) and older (mean age = 64) adults were asked to recall the dates and make recency judgments for historical events that occurred in each of three time periods between 1862 and 1977. Overall there were no age differences in either the number of correct dates or the number of correct recency judgments. However, younger adults tended to perform better than older adults on events that occurred most recently, and performed significantly better on events that occurred during the respective times of their youth. In addition, somewhat different patterns of performance on the two dependent measures suggested that detailed information about events is lost with time, but that more general information may not decline with time.

Self-ratings of past, present, and future cognitive performance across adulthood

Age differences in self-ratings of present and projected past and future cognitive performance were examined across a variety of cognitive domains. Participants (N = 151) in their twenties, forties, sixties, and eighties completed a battery of cognitive tasks and rated their present performance, likely performance five years ago (past), and projected performance five years hence (future) for each task. Performance on fluid/speeded intelligence, memory, and reasoning tasks followed a progression of poorer performance with age. Age differences in self-assessment of projected past and future performance were found, as were age by time interactions. Self-ratings of participants in their twenties tended to reflect projections of continuing improvement from past to present to future, but self-ratings of participants in older age groups tended to reflect perceptions of increasing decline over time. These findings suggest that age differences in self-ratings of cognitive performance may be related to age specific implicit theories of cognitive development.

Late recurrence of testicular tumor (choriocarcinoma)

A case is presented in which a large choriocarcinoma was excised from the contralateral retroperitoneal area 15 years after a radical orchiectomy for seminoma with elements of embryonal carcinoma.