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D E Bockman

Publications and source records attributed to D E Bockman.

81 records · Page 5Linked to original sources
PubMed1970

Suppression of immunoglobulin G synthesis as a result of antibody-mediated suppression of immunoglobulin M synthesis in chickens.

Development of heterogeneity of immunoglobulin classes has been investigated in the chicken by studying the effects of antibody-mediated suppression of IgM synthesis. Treatment of 13-day embryos with purified goat antibodies to IgM resulted in the elimination of IgM-containing cells from the bursa of Fabricius of 16- and 19-day embryos. When combined with bursectomy at hatching, administration of anti-IgM in ovo suppressed the synthesis not only of IgM but also of IgG. A number of experimental birds lacked detectable circulating immunoglobulins, plasma cells, and germinal centers when killed at 10 weeks of age. Contrasting results were obtained when IgM synthesis was suppressed after bursectomy at hatching. Birds so treated produced little or no IgM but synthesized normal amounts of IgG. The results suggest that, within the bursal environment, IgG-producing cells arise exclusively from cells that previously synthesized IgM. A model for generation of antibody variability is presented.

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PubMedDate not supplied

Morphology of the exocrine pancreas related to pancreatitis.

It has been assumed in the past that pancreatic acinar cells represent an irreversible end stage in development. Consequently, when there was an increase in structures that had the morphology of ductules, the interpretation was that they were derived from the proliferation of stem cells and/or pre-existing ductular cells. Pancreatitis, however, is regressive in nature [Bockman (1984) In: Pancreatitis: Concepts and Classification. Gyr, K.E., Singer, M.V., Sarles, H., eds. Elsevier, Amsterdam, pp. 11-15]. That is, it is characterized by parenchymal destruction and loss, rather than by expansion of parenchyma. Furthermore, it was assumed that the organization of the pancreatic parenchyma is like bunches of grapes, with spheroidal acini representing the grapes, and the ductules representing the stems. Given this organization, it would be difficult to understand how regressive changes could lead to clusters of ductular structures. Investigations using three-dimensional reconstruction and retrograde injections have altered our idea of pancreatic organization. In addition to spheroidal acini, there also are other shapes, including tubular acini. Moreover, ductules do not necessarily stop when they encounter an acinus. They may emerge on the other side. Combined ductular and acinar lumina may anastomose with each other. It is now clear that pancreatic acini may undergo redifferentiation, taking on the morphology of ductules and forming tubular complexes during pancreatitis, as well as in response to pancreatic cancer, cystic fibrosis, or blockage of the ductal system. With this understanding of pancreatic architecture and morphological plasticity, it is easier to understand the changes one sees with pancreatic diseases.

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