Biomedical subjects

C M Dayton

Publications and source records attributed to C M Dayton.

7 recordsLinked to original sources

PubMed2000

Telomerase activity in B-cell non-Hodgkin lymphoma.

BACKGROUND: Studies have shown telomerase activity to be present in some B-cell non-Hodgkin lymphomas (B-NHLs). However, no large studies have assayed telomerase activity in a systematic and quantitative manner. Furthermore, the relation between telomerase and proliferation suggested by in vitro studies has not been adequately tested in B-NHLs in vivo. This information is necessary to understand the relation between proliferation and telomerase and to predict the efficacy of antitelomerase drugs currently in development. METHODS: Eighteen benign biopsies and 111 B-NHLs of varying types were classified according to the revised European-American classification of lymphoid neoplasms (REAL classification) and assayed for telomerase activity and proliferation index (PI). RESULTS: All B-NHLs contained telomerase activity except for low grade marginal zone B-cell lymphomas (MZBCLs) (96 of 111, 86%) (chi(2) 95.90, P < 0.001). Telomerase activity correlated with PI (r = 0.7536, r(2) = 0.5678, t = 10.51, P < 0.001) and showed a threshold whereby telomerase activity was not present below a PI of 9.2% (t = 4.875, P < 0.001). CONCLUSIONS: The level of telomerase activity fell within characteristic ranges and generally correlated with the clinical aggressiveness of each B-NHL category. Low grade MZBCLs of extranodal, nodal, and splenic types were unique among the categories of B-NHL in lacking or containing very little telomerase activity. The association between telomerase activity and PI is evidence that telomerase is controlled in vivo along with the cell cycle and is not constitutively active in B-NHL. These data provide evidence that antitelomerase drugs may be efficacious in most types of B-NHL.

Cell Division↗

PubMed1998

Sudden infant death with external airways covered: case-comparison study of 206 deaths in the United States.

OBJECTIVE: To study factors associated with sudden infant deaths occurring with the external airways (ie, nose and mouth) covered by bedding. DESIGN: Case-comparison study of infants dying with vs those dying without the external airways covered. SETTING: Death-scene investigation and reconstruction at the site of death using an infant mannequin; 18 metropolitan areas. PARTICIPANTS: Caregivers for a consecutive sample of infants who died of sudden infant death syndrome (SIDS). Complete data from 206 of 382 eligible cases. MAIN OUTCOME MEASURES: Among infants dying suddenly and unexpectedly, an analysis of whether sociodemographic risk factors for SIDS, sleep practices, or bedding increased the risk of dying with the external airways covered. RESULTS: Data were analyzed by using univariate and 2 types of multivariate risk analysis, logistic regression and latent class. Of the victims, 59 (29%) were found with the external airways covered. Conventional risk factors for SIDS did not affect the risk of death with the external airways covered. Factors increasing the risk of death with the external airways covered included prone sleep position (odds ratio [OR], 2.86) and using soft bedding (OR, 5.28), such as comforters (OR, 2.46) and pillows (OR, 3.31). Infants at low risk for death with the external airways covered slept in the prone position, but rarely on a pillow, comforter, or other bedding that allowed a pocket to form beneath the face. All 9 infants who were positioned supine or on one side for sleep and found with the external airways covered had turned and were found dead in the prone position. CONCLUSIONS: Sudden infant deaths with the external airways covered were common in the United States when most infants slept prone. Soft bedding, including pillows and comforters, increased the risk that an infant who died would be found with the external airways covered. Therefore, these items should not be placed near infants, regardless of the sleep position.

Bedding and Linens↗

PubMed1997

Conceptualizing oral health and oral health-related quality of life.

This investigation considers oral health from a health-related quality of life perspective using a multidimensional concept representing a combination of impairment, function, perceptions, and/or opportunity. A subset of dentate individuals aged 18 and older from a national probability sample of the U.S. was selected for the reported analysis with data available from personal interviews, self-administered questionnaires, and oral examinations. Impairment was represented by clinically assessed active diseases and sequelae of diseases and self-reported acute symptoms. Other domains are represented by self-reported problems with function, perception of control over oral health, satisfaction with teeth, value attributed to oral health, and opportunity to obtain dental care. Principal components analysis with varimax rotation provided a structure to interpret four factors: accumulated oral neglect, self-perceived symptoms and problems, reparable oral diseases, and oral health values and priorities. Approximately 50% of the variance was explained by these four factors. Factor-based scores, envisioned as an index or summary measure representing the combination of variables identified in each factor, were used to assess potential validity. Whites had lower levels of accumulated oral neglect, fewer symptoms, and less reparable oral disease, but similar oral health values, than non-whites. Level of formal education was associated with each of the four factor-based scores. Age was directly associated with accumulated oral neglect, but the youngest age group had significantly more reparable oral diseases. Individuals with a dental visit in the past two years had considerably less accumulated oral neglect, fewer self-perceived problems, less reparable oral disease, and higher values of oral health than those without a dental visit in the past two years. Ordinary least square regressions were performed on each of the four factor-based scores using eight sociodemographic and economic variables. All four regression models were significant, with only the education variable being significant across all models. These analyses provide no evidence for one unique factor representing oral health. Rather, a conceptual framework for oral health appears to be represented by a set of reasonably independent components, including two groups of clinically assessed oral health, which together more fully represent oral health than any one single variable. Conceptualizing and measuring oral health multidimensionally leads us closer to examining it as part of general health.

Adolescent↗

PubMed1980

A left-right identification scale for clinical use.

The contribution of this research is a left-right identification scale which is relatively simple to administer, easy to score, and subject to low error rates. The research is unusual in that, rather than use subjective procedures (i.e., inspect data patterns), a probabilistic model was used to access fit to a linear hierarchy to response data. The resulting validated scale should be of use to researchers and clinicians alike.

Child↗

PubMed1978

Further study of the X-linked recessive gene hypothesis for inheritance of spatial abilities.

Two measures of spatial ability were administered to 319 undergraduates, 93 parents, and 62 siblings. Although males outperformed females on both tests, the resulting correlational pattern did not conform to the trait pattern hypothesized on the basis of an X-linked recessive trait. Results from a pedigree analysis, however, were in the expected direction. The inclusion of pedigree analyses is urged in future research.

Female↗

PubMed1976

Factors affecting accuracy of perception on a task requiring the ability to identify viewpoints.

A study was undertaken to determine the relative contribution of age, sex, and three stimulus features (board shape, block arrangement, and block shape) to perceptual accuracy on 39 board/block adaptations of Piaget's three-mountain task. The sample consisted of 830 children (420 1st graders and 410 5th graders) and 130 college students. Stimulus features of the board/block task accounted for between 22% and 26% of the explained variability among accuracy scores; however, interactions of other factors with age were nonsignificant. When data from college students were combined with children, a curvilinear developmental relationship between age and perceptual accuracy was obtained. The board/block task has promise as an instrument for longitudinal studies.

Adolescent↗

PubMed1976

Egocentric error and the construct of egocentrism.

It was hypothesized that perception errors on a task requiring Ss to take different viewpoints could be explained in terms of response bias. Four hundred ten first graders, 421 fifth graders, and 260 undergradutaes' error patterns on 39 board/block adaptations of Piaget's three-mountain task were examined with respect to their front, opposite, and reversed choices of camera position. Front choices or egocentric errors were found, overall, to be independent of grade level. Results from this analysis were consistent with the response bias hypothesis: clearly, making an egocentric error is different from behaving in an egocentric manner.

Adult↗