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Biomedical subjects

R L Davis

Publications and source records attributed to R L Davis.

386 records · Page 22Linked to original sources
PubMedDate not supplied

Tripartite mushroom body architecture revealed by antigenic markers.

We have explored the organization of the axonal lobes in Drosophila mushroom bodies by using a panel of immunohistochemical markers. These markers consist of antibodies to eight proteins expressed preferentially in the mushroom bodies: DAMB, DCO, DRK, FASII, LEO, OAMB, PKA RII, and RUT. Previous to this work, four axonal lobes, two projecting dorsally (alpha and alpha') and two medially (beta and gamma), had been described in Drosophila mushroom bodies. However, our analysis of immunohistochemically stained frontal and sagittal sections of the brain revealed three medially projecting lobes. The newly distinguished lobe, which we term beta', lies along the dorsal surface of beta, just posterior to gamma. In addition to resolving a fifth lobe, our studies revealed that there are specific lobe sets defined by equivalent marker expression levels. These sets are (1) the alpha and beta lobes, (2) the alpha' and beta' lobes, and (3) the gamma lobe and heel (a lateral projection formed by a hairpin turn of some of the peduncle fibers). All of the markers we have examined are consistent with these three sets. Previous Golgi studies demonstrate that each mushroom body cell projects one axon that branches into a dorsal lobe and a medial lobe, or one unbranched axon that projects medially. Taken together with the lobe sets listed above, we propose that there are three major projection configurations of mushroom body cell axons: (1) one branch in the alpha and one in the beta lobe, (2) one branch in the alpha' and one in the beta' lobe, and (3) one unbranched axon projecting to the heel and the gamma lobe. The fact that these neuron types exhibit differential expression levels of a number of mushroom body genes suggests that they may have corresponding functional differences. These functions may be conserved in the larvae, as several of these genes were expressed in larval and embryonic mushroom bodies as well. The basic mushroom body structure, including the denritic calyx, peduncle, and lobes, was already visible by the late stages of embryogenesis. With new insights into mushroom body organization, and the characterization of markers for developing mushroom bodies, we are beginning to understand how these structures form and function.

Animals↗
PubMedDate not supplied

Female employee participation in a worksite mammography screening program.

We conducted a survey of 1,184 women 35 years of age or older who were employees of a company in Los Angeles County, California, to determine why some women participated in a worksite mammography screening program whereas others did not. Of the 111 who accepted a mammogram, 90 responded to the survey; of the 1,073 who declined mammography, 620 responded. The women were predominantly white, were well educated, and had health insurance. Of the 111 women who received mammograms, one was diagnosed with carcinoma. Seventy-three percent of the respondents to the survey 40 years of age or older who declined mammograms had already fulfilled American Cancer Society (ACS) guidelines for mammography screening at the time of the program. Women who accepted a mammogram were more likely to have had at least one previous mammogram than were women who had not met ACS guidelines yet who declined screening. We conclude that many female employees who are white, are well educated, and have health insurance may not participate in a worksite mammography screening program because they have been screened elsewhere. Companies providing worksite mammography screening should target education to women who have not met ACS guidelines, especially those who have never had a mammogram.

Adult↗
PubMedDate not supplied

Smoking during pregnancy among northwest Native Americans.

There is little available information on the smoking habits of Native Americans. The authors used data from the Washington State birth certificate to determine the prevalence of smoking during pregnancy among Native American mothers in Washington State. From 1984 through 1988, 39.8 percent of all Native Americans smoked during their pregnancy. Smoking patterns during pregnancy differed markedly between Native Americans and whites according to maternal age and marital status. The smoking prevalence in Native Americans, adjusted for maternal age and marital status, was 1.3 times higher than that found in Washington State white women. This is the first analysis of statewide smoking rates during pregnancy among Native Americans. The birth certificate can serve as a readily accessible and low cost surveillance system for populations such as Native Americans, who are otherwise difficult to study. Smoking intervention programs need to be targeted at Native Americans, and how their smoking patterns differ from those of the general population needs to be recognized.

Adolescent↗
PubMedDate not supplied

Current federal activities in school health education.

In 1979, the Federal Government released a report, "Healthy People," that examined the major health problems and the associated preventable risks facing Americans. For the school-age population in particular, several problem areas are notable, such as violence (suicide and homicide), accidents, and drug and alcohol abuse. A number of risk factors related to personal behavior have been identified for these and other health problems facing young Americans. Comprehensive school-based health promotion programs have the potential to influence positively the health status of the school-age population. This article highlights some of the more important recent Federal activities related to school-based health education.

Adolescent↗
PubMedDate not supplied

The safety of newborn early discharge. The Washington State experience.

CONTEXT: While early discharge of newborns following routine vaginal delivery has become common practice, its safety has not been firmly established. OBJECTIVE: To assess the risk for rehospitalization following newborn early discharge. DESIGN: Population-based, case-control study. SETTING: Washington State linked birth certificate and hospital discharge abstracts covering 310578 live births from 1991 through 1994. PATIENTS: Case patients were 2029 newborns rehospitalized in the first month of life. Control subjects were 8657 randomly selected newborns not rehospitalized and frequency matched to case patients on year of birth. Cesarean deliveries, multiple births, and births at less than 36 weeks' gestation were not included. MAIN OUTCOME MEASURE: Stratified analyses and logistic regression were performed to assess the risk for rehospitalization within a month of birth after early discharge (<30 hours after birth) compared with later discharge (30-78 hours after birth). RESULTS: Seventeen percent of newborns were discharged early. Newborns discharged early were more likely to be rehospitalized within 7 days (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.11-1.47), 14 days (OR, 1.16; 95% CI, 1.03-1.32), and 28 days (OR, 1.12; 95% CI, 1.00-1.25) of discharge than newborns sent home later. Subgroups at increased risk for rehospitalization following early discharge included newborns born to primigravidas (OR,1.25; 95% CI, 1.07-1.45), mothers younger than 18 years (OR, 1.22; 95% CI, 0.79-1.91), and mothers with premature rupture of membranes (OR, 1.41; 95% CI, 0.85-2.36). Early discharge was also associated with an increased risk of readmission for jaundice, dehydration, and sepsis. CONCLUSION: Newborns discharged home early (<30 hours after birth) are at increased risk for rehospitalization during the first month of life.

Case-Control Studies↗