Biomedical subjects

Cathy Simpson

Publications and source records attributed to Cathy Simpson.

4 recordsLinked to original sources

PubMed2006

Active prompting to decrease cell phone use and increase seat belt use while driving.

Automobile crashes are the leading cause of death for those aged 3 to 33, with 43,005 (118 per day) Americans killed in 2002 alone. Seat belt use reduces the risk of serious injury in an accident, and refraining from using a cell phone while driving reduces the risk of an accident. Cell phone use while driving increases accident rates, and leads to 2,600 U.S. fatalities each year. An active prompting procedure was employed to increase seat belt use and decrease cell phone use among drivers exiting a university parking lot. A multiple baseline with reversal design was used to evaluate the presentation of two signs: "Please Hang Up, I Care" and "Please Buckle Up, I Care." The proportion of drivers who complied with the seat belt prompt was high and in line with previous research. The proportion of drivers who hung up their cell phones in response to the prompt was about equal to that of the seat belt prompt. A procedure that reduces cell phone use among automobile drivers is a significant contribution to the behavioral safety literature.

Accidents, Traffic↗

PubMed2003

Desmosomal proteins, including desmoglein 3, serve as novel negative markers for epidermal stem cell-containing population of keratinocytes.

No single method has been universally adopted for identifying and isolating epidermal stem/progenitor cells, and the emergence of new markers of stem cell populations is worth exploring. Here we report, for the first time, that clusters of basal keratinocytes at the tips of the rete ridges in human palm, previously recognised as a major repository of stem cells, had very low levels of desmoplakin protein and mRNA expression, compared with cells at the sides of the ridges or above the dermal papillae. We found that in populations of palm keratinocytes, selected by their ability to adhere rapidly to type IV collagen, there were significantly reduced levels of desmoplakin and other major desmosome proteins. We then showed that a low desmoglein 3 (Dsg3) expression on the cell surface could be used to enrich for a cell population with high clonogenecity, colony forming efficiency and enhanced proliferative potential, but with a low ability to form the abortive clones, compared with populations with a higher Dsg3 expression. Moreover, stringent sorting of populations showing both beta1 integrin-bright and Dsg3-dull expression enabled even further enrichment of a population containing the putative epidermal stem cells. These findings provide the basis for a new strategy for epidermal stem/progenitor cell enrichment, and encourage further study of the role of desmosomes in stem cell biology.

Cadherins↗

PubMed2003

Diagnostic compared with abstinence outcomes of day treatment and contingency management among cocaine-dependent homeless persons.

Substance use disorder diagnoses were used as a treatment outcome measure in a randomized comparison of day treatment (DT) and day treatment plus contingency management (DT+) among homeless persons with primarily crack/cocaine disorders. Participants (N = 127, DT+ = 69, DT = 58, 73.2% male, 82.7% African American) were assessed at baseline and 6-month treatment completion. Binary positive and negative diagnostic outcomes for cocaine, marijuana, and alcohol were compared by treatment group. DT+ was 2.1 times more likely to have a positive treatment outcome than DT. Concordance between diagnostic change and point and continuous abstinence outcomes were found. The use of diagnostic change can be a practical addition to drug toxicology and self-report treatment outcome measures for research and practice.

Adult↗

PubMed2002

Inhibitory effects of apoptotic cell ingestion upon endotoxin-driven myeloid dendritic cell maturation.

Dendritic cells (DCs) are the sentinels of the immune system, able to interact with both naive and memory T cells. The recent observation that DCs can ingest cells dying by apoptosis has raised the possibility that DCs may, in fact, present self-derived Ags, initiating both autoimmunity and tumor-specific responses, especially if associated with appropriate danger signals. Although the process of ingestion of apoptotic cells has not been shown to induce DC maturation, the exact fate of these phagocytosing DCs remains unclear. In this paper we demonstrate that DCs that ingest apoptotic cells are able to produce TNF-alpha but have a diminished ability to produce IL-12 in response to external stimuli, a property that corresponds to a failure to up-regulate CD86. By single-cell analysis we demonstrate that these inhibitory effects are restricted to those DCs that have engulfed apoptotic cells, with bystander DCs remaining unaffected. These changes were independent of the production of anti-inflammatory cytokines TGF-beta1 and IL-10 and corresponded with a diminished capacity to stimulate naive T cells. Thus, the ingestion of apoptotic cells is not an immunologically null event but is capable of modulating DC maturation. These results have important implications for our understanding of the role of clearance of dying cells by DCs not only in the normal resolution of inflammation but also in control of subsequent immune responses to apoptotic cell-derived Ags.

Animals↗