[Historical recollection Medical School of the University of Puerto Rico 1950-2000]. / Recuento histórico Escuela de Medicina de la Universidad de Puerto Rico 1950-2000.

The School of Medicine of the University of Puerto Rico was founded in 1950 with the mission of educating the much needed physician workforce in order to improve the health of a large portion of the population in Puerto Rico. The main events in its first fifty years of existence are summarized. Emphasis is given to the unique, mutually dependent association between the School of Medicine and the Department of Health of Puerto Rico. Soon after its organization, the school became a principal protagonist in the delivery of specialized medical care to the medically indigent population within the existing Regionalization Program of Health Care services in the island. With the creation and development of various other academic and health services institutions in the island, and the advent of a new system of health care in 1993, based on managed care; the School's interdependence with the Department of Health and its role in the direct care of the medically indigent have waned drastically. The School now faces its greatest challenges as it begins to insert itself into the economically competitive arena of the new health care system; and in redefining its commitments, while searching for new resources, alliances, teaching faculty, hospitals and clinics, enabling it to maintain its leadership in medical education, specialty training and scientific research in Puerto Rico.

p172: An alveolar type II and Clara cell specific protein with late developmental expression and upregulation by hyperoxic lung injury.

The epithelium of the alveolus and distal airway meets unique requirements, functioning as a gas exchange membrane and barrier to alveolar flooding by vascular contents as well as to bloodstream contamination by airborne toxins and pathogens. Gene products specifically expressed by this epithelium, notably the surfactant apoproteins, have had important clinical application. No cell surface antigen specific for alveolar type II and Clara cells has been described. We report the biochemical characterization, tissue and developmental expression, and upregulation by injury of a 172 kD protein recognized by a monoclonal antibody, 3F9, synthesized in response to immunization with freshly isolated rat alveolar type II cells. p172 is expressed in a polarized fashion by the apical surface of rat alveolar type II and Clara cells. An immunohistochemical survey of various rat tissues and organs reveals lung specificity. p172 is first detectable in rare epithelial cells at 19 days of gestation, a time when the fully differentiated alveolar type II cell is identified by the first detection of lamellar bodies. There is a dramatic increase in p172 expression just prior to birth. Hyperoxic lung injury results in increased expression of p172. The upregulation of p172 by hyperoxia and its cell-specific expression suggests an important adaptive function.