Budget response to volume variability.
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Biomedical subjects
D Wilburn
Publications and source records attributed to D Wilburn.
Dominance of a tumor subpopulation line in mixed heterogeneous mouse mammary tumors.
When mixtures of cell lines 168 and 4T07, both derived from the same mouse mammary tumor, were injected into syngeneic mice, the resulting tumors, analyzed over a large size range by colony-forming assays in selective media, consisted primarily of line 4T07, even when the ratio injected was 100:1 or greater in favor of line 168. This result indicated a suppression of growth of line 168, since the volume-doubling time of line 168 tumors in the absence of line 4T07 was one-half that of line 4T07 tumors. That growth suppression was not due to inhibition of line 168 by immunity induced to line 4T07 was shown in two ways: (a) line 168 tumors grew almost as well in mice preimmunized with line 4T07 as in controls, whereas line 4T07 tumor growth was strongly inhibited in preimmunized mice; and (b) the final composition (favoring line 4T07) in mixed tumors was similar in tumors grown in mice immunosuppressed by irradiation to that in nonirradiated controls. The strong suppression of line 168 did not occur when the two cell lines were injected simultaneously at different s.c. sites, nor did it occur when line 168 cells were injected in mixtures with lethally irradiated line 4T07 cells. Line 4T07 cells also suppressed the growth of line 168 cells in monolayer cultures. It was not likely that suppression was due to competition for growth factors, since the effect required cell contact. Suppression probably was not mediated through junctional communication, since these cells do not engage in metabolic cooperation. We suggest that a growth-inhibitory factor produced by line 4T07 mediates the suppression of 168 cells.
Animals↗
Comparison of the scope of allopathic and osteopathic medical school health promotion programs for students.
PURPOSE: To compare the number and scope of health promotion programs for students in allopathic and osteopathic medical schools in the U.S. and Canada. DESIGN: A one-time cross-sectional survey design was applied in this study. SETTING: This study was conducted in 141 accredited allopathic and 17 accredited osteopathic medical schools. SUBJECTS: A total of 158 representatives from the allopathic and osteopathic medical schools participated in this study. The response rate for the survey was 100%. MEASURES: A structured telephone interview was conducted to survey representatives from the medical schools. The survey contained 85 multiple-choice questions organized into four sections: administrative characteristics, types of institutional and health promotion program policies, participation incentives and facilities, and type/scope of health promotion program activities. Chi-square analysis was used to analyze survey variables by type of medical education and level of intervention. RESULTS: Of the 158 medical schools, only 20% (n = 32) provided a health promotion program for students. Although osteopathic institutions (29.4%) had a greater percentage of programs than allopathic schools (19.2%), there was no significant difference in scope of program offerings by type of medical education. Allopathic programs offered exercise and nutrition/weight management significantly more often and at a higher level of intervention. Lastly, allopathic programs had significantly more monetary resources available for programming. Following prudent research protocol, investigators should be mindful of the limitations of this study. In this study, some school representatives chose not to answer personnel- and finance-related questions. Additionally, because of the self-report nature of the survey, the responses given to the questions may not have been accurate. CONCLUSION: Allopathic and osteopathic medical school health promotion programs for students were very similar in scope.
Canada↗