A comparative analysis of Emergency Department (ED) utilization by 2936 older-adults, old, and old-old patients was conducted in the only hospital available for residents of a vast geographical region. All patients (45+) who arrived at the ED during the first week of every even month from September 1986 to August 1987 were selected for the study. No significant differences were found among the three groups with regard to sociodemographic characteristics other than age. Data showed that the old-old use the ED approximately twice as much as the old and the older-adults; they also use the ED more often than the two other groups during the winter season. These two findings indicate the utility of viewing the old-old not only as a part of the elderly population, but also as a unique risk group. Hospitalization rates present a different pattern: they double in each age group moving from the youngest to the oldest. Complaints of an internal medicine nature are more often presented by the two groups of the elderly in comparison to the older-adults, and are followed by more frequent hospitalizations in internal medicine wards. Such findings have practical implications, and should be taken into consideration by policymakers.The ability to manipulate certain physiological processes by using the immune system, so as to regulate endocrine secretions and/or actions is clearly possible. The dramatic effects of immunocastration and the ability to increase ovulation rates in sheep are probably the best examples. Other approaches along similar lines have produced equivocal results, the effects of immunization against somatostatin being the most notable case. Although anti-idiotypic antibody approaches to producing hormone mimics have also been shown to be attainable and, indeed, possibly involved in certain auto-immune dysfunctions of the endocrine system, to date no successful applications of this approach have been demonstrated in commercial livestock. The ability to enhance hormone action using antibodies is an extremely promising area. Its prospects probably hinge on the ability to synthesize suitable short peptides which will mimic epitopes on the hormone and so permit the development of active immunization techniques to produce polyclonal antibodies of restricted and enhancing specificity. It seems less likely that administration of hormones pre-complexed to monoclonal antibodies has any potential as a practical approach to manipulating animal productivity. All of these approaches involving active immunization suffer the same limitations: the highly variable response of individual animals and the general inability to regulate the duration of the response; a need to find suitable adjuvants to replace the almost universally used and commercially unacceptable Freund's adjuvant; and the problem of trying to generate what, in most cases, is an auto-immune response. A second group of approaches consists of attempts to use antibodies in their classical role, that is by targeting antigens or cells for destruction by the immune system. These include, for example, antibodies directed against adipose tissue or cytotoxic antibodies to specific hormones aimed at destruction of the hormone-secreting cells. Since these are passive immunization techniques, the antibodies can be assessed carefully in vitro and administered in appropriate doses. However, success in these applications is largely dependent on the inability of damaged tissues to regenerate, since retreatment is generally precluded because of the anti-immunoglobulin response induced in treated animals. Toleragenic forms of such antibodies or the use of appropriate immunosuppressants may ultimately remove this limitation. Perhaps the greatest current limitation to the use of all of these techniques in animal production systems, however, is public resistance to the use of such techniques.(ABSTRACT TRUNCATED AT 400 WORDS)Two groups of maxillary premolars with Class I cavities were prepared with one marginal ridge thickness to a width of 1.0 mm. One group was restored with amalgam and the other group with composite resin. Two groups of Class II cavities also were prepared and restored with amalgam and composite resin. The teeth in the four treatment groups were subjected to a centric load at the marginal ridge until fracture occurred. A two-factor analysis of variance revealed a statistically significant difference between the class of preparation (Class I preparations were weaker than were Class II preparations) but differences in strength between restorative materials (composite resin versus amalgam) and the interaction effect (class of preparation x restorative materials) were not found to be statistically significant (alpha =.05). A Newman-Keuls sequential range test found no statistically significant differences in strength between groups (alpha =.05). Fracture patterns were observed under scanning electron microscope. Fractures extended into the enamel and into the material in the Class I composite resin, Class I amalgam, and Class II composite resin restorations. Fractures extended only into the material in Class II amalgam restorations.The results of the follow up of the Salmonella enterica infections seen in the Hospital San Agustin in Avilés (Astur