SummaryWe examined structure and expression of the p53 and Rb genes in a C3HOS transplantable mouse model of osteosarcoma. The results were compared to analogous studies conducted with five human osteosarcoma cell lines. The p53 gene was found rearranged in the mouse tumour. The rearrangement mapped to the first intron region of the p53 gene and as a result, no p53 expression could be detected in C3HOS tumours. Using p53 genomic probes, we have detected the same rearrangement in the original radiation-induced tumour and the various clones that were isolated from it. Deletion and rearrangement of the p53 gene were also found in three out of five of the human osteosarcoma cell lines . No p53 expression could be detected in these three cell lines. In the affected human osteosarcoma cell lines, the rearrangement involved the first intron region. In addition, the mouse tumour was analysed for structural and expression changes in the Rb and the c-myc genes. Normal expression of both genes were detected in the murine tumour. Only one (Saos-2) human osteosarcoma cell line exhibited gross structural alteration in the retinoblastoma gene. The results suggest that the inactivation of p53 may be an important step in the development of osteosarcomas, and that a rearrangement affecting the first intron is common in osteosarcomas.

Objective. To measure changes in pharmacy and medical students' physician-pharmacist collaboration scores resulting from a workshop designed to promote understanding of the others' roles in health care. Methods. More than 88% of first-year pharmacy (n 5 215) and medical (n 5 205) students completed the Scale of Attitudes Toward Physician-Pharmacist Collaboration on 3 occasions in order to establish a baseline of median scores and to determine whether the scores were influenced by an interprofessional workshop. Results. Participation in the interprofessional workshop increased pharmacy students' collaboration scores above baseline (p50.02) and raised the scores of medical students on the education component of the collaboration survey instrument (p50.015). The collaboration scores of pharmacy students greatly exceeded those of medical students (p,0.0001). Conclusion. A workshop designed to foster interprofessional understanding between pharmacy and medical students raised the physician-pharmacist collaboration scores of both. Crucial practical goals for the future include raising the collaboration scores of medical students to those of pharmacy students.

Objective. To determine the impact of performing critical-thinking and reflection assignments within interdisciplinary learning teams in a biochemistry course on pharmacy students' and prospective health professions students' collaboration scores. Design. Pharmacy students and prospective medical, dental, and other health professions students enrolled in a sequence of 2 required biochemistry courses. They were randomly assigned to interdisciplinary learning teams in which they were required to complete case assignments, thinking and reflection exercises, and a team service-learning project. Assessment. Students were asked to complete the Scale of Attitudes Toward Physician-Pharmacist Collaboration prior to the first course, following the first course, and following the second course. The physician-pharmacist collaboration scores of prospective health professions students increased significantly ( p,0.001). Conclusions. Having prospective health professions students work in teams with pharmacy students to think and reflect in and outside the classroom improves their attitudes toward physician-pharmacist collaboration.

A group-set of male Fischer 344 rats was kept on a choline-devoid (CD) diet for 3, 6, 9, 12 or 16 months. A second set was fed the same diet for 3, 6 and 9 months, followed by a control, choline-supplemented diet for 3 months. A third set was fed the CD diet for 0, 3, 6, 9 and 12 months and the control diet for the duration (16 months) of the experiment. [3H]Thymidine was injected into some of the animals to assess the extent of liver cell proliferation. In the latter animals, liver triacylglycerols were also determined as an index of the hepatonecrogenic action of a CD diet. Foci of enzyme-altered hepatocytes were detected histochemically and the presence of tumors was established histologically. Cell proliferation and triacylglycerols were both high after 3 months and declined steadily as the length of CD diet feeding increased. Upon subsequent feeding with the control diet, triacylglycerols promptly cleared from the liver, while cell proliferation remained at reduced but still relatively high levels for at least 3 months. Increasing but small numbers of foci of enzyme-altered hepatocytes were detected in some of the rats under experimentation for 6 months or longer. The incidence of hepatocellular carcinomas was 13, 27, 33 and 73% respectively in rats fed the CD diet for 3, 6, 9 or 12 months and the control diet for the duration of the experiment. On the other hand, only 26% of the rats fed exclusively the CD diet for 16 months developed carcinomas. The results were taken as evidence that: (i) liver cell proliferation persists beyond discontinuation of a CD diet; (ii) the liver contains initiated cells--capable of full evolution to cancer even in the absence of active promotion--after a relatively short 3-month exposure to a CD diet; and (iii) occurrence of a late event(s) is critical for the genesis of the tumors. Whether a CD diet is a complete carcinogen able to initiate de novo liver cells or acts merely as a promoter of the evolution of endogenous initiated cells is briefly discussed.