Search PubMed⌕ Search

Biomedical subjects

D C Park

Publications and source records attributed to D C Park.

At least 37 records · Page 2Linked to original sources
PubMed1997

Interrelations of age, self-reported health, speed, and memory.

Contributions of self-reported health to adult age differences in perceptual speed and memory were assessed for 301 adults ages 20-90. Participants were asked 4 health status questions, given 3 perceptual speed tests, 2 working memory tests, and 2 memory tests. Self-reported health was found to predict speed better than it predicted memory. Covariance structural equation modeling was used to assess the relations among age, self-reported health, perceptual speed, working memory, and memory. The results support the hypothesis that any effects of self-reported health on age differences in memory are mediated by perceptual speed.

Adult↗
PubMed1997

Adherence to antihypertensive medications across the life span.

Although treatment for hypertension is readily available, poor control of hypertension is a major health problem frequently manifested in late life. Researchers believe that one of the major causes of uncontrolled hypertension is failure to take medication as directed. In this preliminary study, the medication-taking behaviors of 48 adults diagnosed with hypertension, ranging in age from 35 to 87, were recorded for 2 months with credit card-sized bar-code scanners. The social-cognitive model (Park, 1992) for understanding medication adherence, which proposes that medication adherence is governed by both beliefs and cognitive factors, was used as a basis for this research. Therefore, measures of health behaviors, attitudes about health and medication taking, and cognitive function were recorded, as well as blood pressure readings. The main findings were that (a) the oldest-old and groups of middle-aged adults were the most nonadherent, whereas the young-old were more likely to adhere than the other age groups; (b) high blood pressure readings predicted adherence to antihypertensive medications; and (c) medication beliefs influenced adherence in some situations.

Adult↗
PubMed1996

Cloning and characterization of a Schizophyllum gene with A beta 6 mating-type activity.

The A-pathway of development in the basidiomycete fungus Schizophyllum commune may be activated by either of two mating-type loci, A alpha and A beta. A alpha consists of two multiallelic genes, Y and Z. Y contains a putative homeodomain; Z contains a homeodomain-related region. Non-self combinations of Y and Z form heteromultimers which are thought to be transcription factors of developmental genes. To more completely understand A-regulated development it is necessary to address the issue of functional redundancy, i.e., how do two different mating loci, A alpha and A beta, both manage to regulate the same pathway. Here we report the structure of a gene with A beta 6 activity. This gene, denoted A beta V6, encodes a deduced polypeptide of 640 amino-acids with a homeodomain motif. V6 also contains a 20-amino acid sequence that is conserved in A alpha Y1, Y3 and Y4. Except for the homeodomain and the conserved sequence, the deduced V6 polypeptide shows no significant identity to A alpha Y, A alpha Z, or other known proteins. The presence of a homeodomain suggests that V, like Y and Z, may be a regulatory protein for genes in the A-pathway. Thus while A alpha and A beta encode different proteins, the general mechanism by which A alpha and A beta components signal A-regulated development may be similar.

Amino Acid Sequence↗
PubMed1996

Mediators of long-term memory performance across the life span.

An individual-differences approach was used to examine the component processes that predict episodic long-term memory performance. A total of 301 participants ages 20-90 received a 7-hr cognitive battery across 3 days. Key constructs hypothesized to affect long-term memory function were assessed, including multiple measures of working memory and perceptual speed. Latent-construct, structural equation modeling was used to examine the relationship of these measures and age to different types of long-term memory tasks. Speed was a key construct for all 3 types of memory tasks, mediating substantial age-related variance; working memory was a fundamental construct for free and cued recall but not spatial memory. The data suggest that both speed and working memory are fundamental to explaining age-related changes in cognitive aging but that the relative contributions of these constructs vary as a function of the type of memory task.

Adult↗
PubMed1995

The A alpha mating-type transcripts of Schizophyllum commune.

A alpha 1, A alpha 3, and A alpha 4 ds- and ss-DNA probes from the polymorphic A alpha mating-type locus of Schizophyllum commune were used to probe Northern blots of poly(A+) RNA extracted from strains of various A alpha mating types. The purpose of these experiments was to identify, map, and characterize the transcripts produced from the regions of the A alpha locus. The transcripts unique to A alpha mating type map colinear with the open reading frames identified from DNA sequence and are encoded within the fragments which activate the A developmental pathway in transformation. These data confirm the existence and structure of the previously hypothesized Y and Z A alpha mating-type genes. Transcripts from the Y and Z genes are present in vegetative cells of homokaryons and dikaryons and in cells of the fruiting bodies. The presence of the transcripts throughout the life cycle is consistent with the model of Y and Z proteins as "master switches" of A-regulated development.

Blotting, Northern↗
PubMed1994

Implementation and impact of the Patient Self-Determination Act.

The Patient Self-Determination Act became effective in December 1991 and mandates that patients be given information about legal rights regarding living wills and durable powers of attorney for health care. We investigated the impact this law has had on hospitals, medical personnel, and patients. We conducted a survey of all hospitals in the state of Georgia, collecting data regarding implementation and knowledge of the law, as well as effects of the law and beliefs about it. The data indicated that hospitals relied primarily on the Georgia Hospital Association for implementation policy, that "minimalist" implementation of the law occurs in most hospitals, and that the biggest perceived problem with the law was the inappropriateness of presenting this information at hospital admission and problems patients had in comprehending the materials presented. Despite these concerns, most respondents did not want the law repealed.

Attitude of Health Personnel↗
PubMed1993

The effects of age, illustrations, and task variables on the performance of procedural assembly tasks.

Older adults may be disadvantaged in the performance of procedural assembly tasks because of age-related declines in working memory operations. It was hypothesized that adding illustrations to instructional text may lessen age-related performance differences by minimizing processing demands on working memory in the elderly. In the present study, younger and older adults constructed a series of 3-dimensional objects from 3 types of instructions (text only, illustration only, or text and illustrations). Results indicated that instructions consisting of text and illustrations reduced errors in construction for both age groups compared with the other formats. Younger adults, however, outperformed older adults under all instructional format conditions. Measures of spatial and verbal working memory and text comprehension ability accounted for substantial age-related variance across the different format conditions but did not fully account for the age differences observed.

Adolescent↗
PubMed1993

Individual difference and contextual variables influence spatial memory in younger and older adults.

This study examined the influence of individual difference and contextual variables on the magnitude of age differences in memory for spatial location. Younger adults and 2 samples of older adults that differed in educational attainment, verbal intelligence, and working memory ability were compared. Ss studied and later recreated an arrangement of small objects that were placed on a plain map or a visually distinctive model. The objects were either unrelated or categorically related items. The results indicated that distinctive context enhanced spatial memory, and the magnitude of the benefit was generally comparable across age groups and stimulus sets. Hierarchical regression analyses confirmed that working memory resources accounted for a sizable proportion of age-related variance in memory for spatial location. The implications of these results for current views on age-related differences in memory for spatial location are discussed.

Adult↗
PubMed1993

The effect of verbal elaborations on memory in young and older adults.

The Stein paradigm was used to examine the circumstances under which verbal elaborations enhance memory in young and older adults. Subjects studied target adjectives that were embedded in one of three sentence contexts that varied in elaboration of the subject-adjective relationship: (1) nonelaborated base sentences; (2) base sentences with semantically consistent, but arbitrary verbal, elaborations; and (3) base sentences with explanatory verbal elaborations that clarified the significance of the subject-adjective relationship. The presence of the elaborations was varied at encoding and retrieval, and cued recall of the target adjectives was tested with incidental and intentional learning procedures. In Experiments 1A and 1B, explanatory elaborations at encoding and retrieval yielded the largest memorial facilitation for both young and older adults, and the benefit was comparable for the incidental and intentional learning measures. In Experiment 2, age-related differences in recall were minimal with explanatory elaborations at encoding and retrieval, but larger age differences occurred in the nonelaborated comparison conditions. In Experiment 3, explanatory elaborations present at encoding but not at retrieval enhanced recall when the original Stein stimuli were used, but not with the present stimuli. The implications of these results with regard to the mnemonic efficacy of verbal elaborations for young and older adults are discussed.

Adult↗
PubMed1992

Medication adherence behaviors in older adults: effects of external cognitive supports.

Medication adherence behaviors of 61 elderly adults were examined using a sensitive microelectronic monitoring device. To assess the effects of external cognitive supports on adherence, different subjects received (a) no intervention, (b) an organizational chart, (c) an over-the-counter medication organizer, or (d) both the chart and organizer. The young-old subjects showed a high rate of adherence (94%) and were not improved by the addition of the interventions. Old-old subjects had a lower rate of adherence (85%) than young-olds. Omission errors were the most frequent mistakes and were lower in the condition in which subjects received both chart and organizer.

Aged↗
PubMed1992

Effect of environmental support on implicit and explicit memory in younger and older adults.

The study addressed 2 major issues: whether there are age differences on an implicit word-stem-completion task and whether age differences on both implicit and explicit memory would decrease with increased environmental support. A total of 287 Ss were presented with words in an incidental learning task with structural or semantic processing. Following 2 filler tasks, Ss received an implicit or an explicit word-stem-completion task. The number of letters in the stem varied from 2 to 4. Results yielded an Age x Memory Task dissociation such that there were large age differences on the explicit task and no age difference on the implicit task, regardless of whether Ss aware of the memory test were included or excluded. There was no evidence that environmental support improved older adults' performance more than that of younger adults on either memory task.

Adolescent↗
PubMed1991

Importance of basic and applied research from the viewpoints of investigators in the psychology of aging.

In this series of presentations, the importance and practical implications of many different research programs in the psychology of aging is presented from the viewpoints of the investigators themselves. These scientists discuss the implications and significance of their work for society as it affects other scientists, policy-makers, the media, and the public. The discussions make clear that the many of the problems associated with aging are essentially behavioral problems which can be prevented through behavioral change in the early as well as later years of the lifespan.

Aged↗
PubMed1991

Cognitive factors and the use of over-the-counter medication organizers by arthritis patients.

The present study investigated the ability of 45 arthritis patients, all using three or more prescription medications, to correctly load their medications into three types of over-the-counter medication organizers. The results indicated that use of a seven-day organizer with compartments for different times resulted in fewer errors than did an hour-by-hour wheel organizer or a seven-day organizer with only one compartment for each day. It was concluded that the seven-day organizer with compartments for different times appears to have the potential to improve compliance behaviors, but the usefulness of the other two organizers in promoting compliance is uncertain. Data analyses also indicated that age was not related to comprehension or loading accuracy of the organizers but that individuals using seven or more prescribed medications were particularly likely to make comprehension errors.

Adult↗
PubMed1990

Effects of distinctive context on memory for objects and their locations in young and elderly adults.

Sharps and Gollin (1987, 1988) reported that older adults' memory for both objects and their spatial location is more facilitated than that of young adults when items are studied in a distinctive visual context. They also reported that age differences in spatial memory and item memory can be ameliorated if the items are studied in a distinctive context. The goal of this study was to verify and extend these findings by examining memory for everyday objects when the objects were studied on a (a) plain surface, (b) black-and-white schematic map, or (c) colored model. In Experiment 1, item memory was examined, and in Experiment 2, spatial memory was studied. The results indicated that spatial memory improved with the addition of distinctive context but item memory did not. Moreover, there was no evidence that elderly adults were more facilitated by the distinctive context than were the young.

Age Factors↗