Higher education and health professions education: shared responsibilities in engaging societal issues and in developing the learned professional.

Higher education and, in turn, health professions education are being buffeted by a multiplicity of external and internal forces. Issues related to fiscal constraints, higher education's crisis of values and the teaching/research and educational outcomes dilemmas are explored. The increasing accountability of higher education by its public, including measures of institutional effectiveness exacerbate these forces. Health professions education programs and their parent universities and colleges must take better advantage of their respective resources and become united around central educational paradigms and outcomes. The ability of higher education and health professions education to engage and connect to societal issues is critical to the appropriate education of the student and to institutional survival. By interweaving the philosophy and culture of the university or college setting in the fabric of health professions education and particularly dental education, an environment could be created that results in a true learning institution. That is, one in which students and faculty learn together in all settings. The outcomes of such engagement are shared responsibilities and the creation of the learned professional, one who is connected to the world and is not trapped by parochial knowledge. Thus, the continuum of health professions education transcends technical and cognitive achievement but addresses core societal values as well. This paper then explores some of the factors impacting upon higher education and assesses their influence on the nation's health professions schools, and, specifically, colleges of dental medicine.

Folate deficiency and in vitro palatogenesis II: Effects of methotrexate on rabbit palate fusion, folate pools, and dihydrofolate reductase activity.

Folate deficiency during pregnancy induced by dietary deprivation or folate antagonists is teratogenic. Methotrexate is a commonly used antifolate drug that produces congenital defects, with the craniofacial complex being especially vulnerable. The molecular action of this compound, therefore, was examined in vitro using fetal rabbit palates in an organ culture system. Dihydrofolate reductase activity was measured in these palates on the 4 days preceding fusion. There was no significant fluctuation in activity with gestational age. Methotrexate treatment of the palates in vitro resulted in significant reduction of enzyme activity and also decreased total folate concentration. However, the in vitro fusion ability of these palates was not altered by exposure to methotrexate. These results suggest that since methotrexate is a potent inhibitor of DNA synthesis and has its maximal effect on rapidly dividing systems, the peak in cellular proliferative activity in the fetal rabbit palate occurs very early in its development.

Ultrastructural alteration of trypsin- and pancreatin-separated embryonic rabbit palate epithelium and mesenchyme.

The effects of 30- and 45-minute trypsin- and pancreatin-separation on embryonic rabbit palate epithelium and mesenchyme were studied with the electron microscope. Changes in epithelium included fragmentation of the basal lamina and formation of cytoplasmic blebs associated with the basal cell layer. Changes in mesenchymal cells were first evident at 45 min of incubation and included cell fragmentation, nuclear pyknosis, and dilation of extracellular space. Results indicate a differential susceptibility of mesenchyme to the separating agent.

Folate deficiency and in vitro palatogenesis I: effects of a folate-deficient culture on rabbit palate fusion and folate pools.

Folate compounds are essential for nucleic acid metabolism and data from in vitro experiments have shown that folatee deficiency during pregnancy induced by dietary deprivation or folate antagonists is teratogenic. The craniofacial complex is a main target of this teratogen, with the lip and palate being especially vulnerable. The direct effect of folate deficiency on a target teratogenic tissue was, therefore, examined in vitro using fetal rabbit palates in an organ culture system. Folate pool sizes in the palates on the 4 days preceding fusion were determined by competitive binding assay. There was a sharp decrease in folate levels from 2.63 +/- 0.86 ng/mg wet wt on Day 15 of gestation to 1.23 +/- 0.35 ng/mg on Day 16 and 0.59 +/- 0.12 ng/mg on Day 17. The folat pool size on Day 14 was found to be quite variable with a mean of 1.93 ng/mg wet wt. Comparable results were obtained when the folate pool sizes were expressed as nanograms of folate per milligram of protein. The effect of a folate-deficiency culture medium on in vitro fusion and folate pool sizes was examined. The results of incubating palatal shelves excised on Days 14, 15, 16, and 17 of gestation for 5, 4, 3, and 2 days, respectively, show that a folate-depleted medium neither prevented nor delayed fusion. An examination of the palatal pool size after incubation in folate-deficient media revealed that while there was some decrease in folate levels, the palates apparently retained sufficient folate to support cellular activity.

Effect of pulsed high frequency electromagnetic radiation on embryonic mouse palate in vitro.

Palatal shelves from 14-day-old embryonic mice were exposed to a 27.12 MHz pulsed non-ionizing radiofrequency (Diapulse) for 20 min followed by 24-hour organ culture in nutrient agar. Diapulse-treated palatal shelves showed induction of cartilage within the mesenchymal compartment and loss of the overlying epithelium in contrast to controls which were free of cartilage. The results are thought to be independent of thermal changes and may be due to calcium flux within the tissue.

Nutrition in growth and development of oral tissues.

The development of teeth, salivary glands, and other oral tissues can be seriously compromised by a deficiency of a number of essential nutrients. Because nutritional stress during critical development periods may decrease the ultimate resistance of the oral tissues to challenge, the prevention of disease and maintenance of oral health are intimately dependent on the nutrient supply during development. Appropriate dietary counseling, particularly with reference to critical developmental times and intake of essential nutrients, can insure optimal oral tissue development.