CEO/supplier dialogue on patient safety. Panel discussion.

Leaders and vendors candidly explore new opportunities for industry standards, work-force training, and patient-focused care.

Networks help assure survival. Interview by Donald E.L. Johnson.

Health care is increasingly a regional business rather than a national one, so hospitals should join or form local networks of providers, insurers and managed care entities, says Gary A. Mecklenburg, president and CEO of Northwestern Memorial Hospital, Chicago, in an interview with Health Care Strategic Management's Donald E.L. Johnson. Institutions that don't participate in the regionalization of health care could be left out. Mecklenburg, who is also president and CEO of the Northwestern Healthcare Network, expects hospital networks, insurers and managed care providers to form more exclusive or limited relationships. Northwestern Memorial is a 723-bed hospital and academic institution with a medical staff of 1,000 physicians. The Northwestern Healthcare Network is an organization formed in 1990 which brings together Northwestern Memorial, Children's Memorial, Evanston, Glenbrook and Highland Park Hospitals under a holding company.

In vivo studies of factors influencing mast cell numbers in rat skin.

In order to examine the biological relevance of known in vitro stimuli for mast cell growth, the following substances were injected at two day intervals into the skin of Wistar rats: Ascaris Ag, epidermal growth factor, basic fibroblast growth factor, fibronectin, phytohemagglutinin-stimulated spleen cell supernatants, L-cell fibroblast supernatants and horse serum alone or in combination with L-cell supernatants. In some experiments, rats were also injected with fresh or cultured peritoneal cells. Single injections of the different factors had no significant effect on mast cell numbers. After multiple injections (4-10 x), deep dermal and submuscular mast cell numbers increased most markedly in ascaris sensitized animals at sites of ascaris antigen injections and in normal animals in response to a combination of horse serum and L-cell supernatants. Less pronounced increases occurred with all other test substances except for epidermal growth factor which was inactive. Mast cell numbers were also increased at sites of injections of immature, cultured mast cells and less so after injections of mast cell precursors and mature cells. Taken together, these data show that in vivo growth and differentiation of cutaneous mast cells can be influenced by several fibroblast- and lymphocyte-derived growth factors.

In vivo increase of cutaneous mast cells in response to specific mediators and ascaris antigen.

In order to investigate mechanisms underlying the accumulation of connective tissue mast cells in tissues, common chemotactic and growth factors as well as ascaris antigen were injected into the skin of Wistar rats. Only after multiple injections was a significant increase of mast cells observed with a mixture of horse serum, 15%, and L-cell supernatant, 20%, in normal animals and with Ascaris antigen in sensitized animals only. Smaller increases were observed with repeated injections of mitogen-stimulated spleen lymphocyte supernatants, with L-cell supernatants, and with fibroblast growth factor. This delayed accumulation of mast cells and the previously observed inability of mast cells to migrate in vitro would suggest that mast cell precursors immigrate into tissue sites in response to chemotactic factors to differentiate there into mature cells under the influence of specific growth factors.

Types and uses of hospital information systems expand.

Computerized hospital information systems are expanding to use new technological developments and to perform new applications, but planning, management, and costs of these systems continue to be major concerns.