Composition of human islet cell preparations for transplantation

To study the cellular composition of human islet cell isolates for transplantation, formalin-fixed and paraffin-embedded cell pellets were stained by the immunoperoxidase method with a panel of antibodies characterising endocrine, epithelial, soft tissue and haematolymphoid components. Immediately after separation, the isolates contained 30-80% islet cells, differing mainly in the content of islet and acinar cells, whereas the soft tissue, ductal/ductular and haematolymphoid elements comprised a relatively constant 10-20%. After 1 week in culture the islet cell content of less highly purified isolates (30-40% islets) dropped dramatically to 5%. The highly purified isolates (70-80% islets) showed only a minimal change in cellular composition; however, approximately two-thirds of islet cells were degranulated and did not stain for insulin. Haematolymphoid components were still present in all cultured isolates. We conclude that primarily mechanical purification methods and short-term culture are not sufficient to eliminate highly immunogenic cells. In addition, short-term culture is deleterious to the isolate if a significant number of acinar cells is still present after enrichment. © 1992 Springer-Verlag

Mediation and the Best Interests of the Child from the Child Law Perspective

What is the best interests of the child in family mediation and is mediation in the best interests of the child? In this article, I use child law and the United Nations Convention on the Rights of the Child combined with mediation theory to discuss these questions. Both mediation and the best interests of the child are open for multiple interpretations. Using facilitative and evaluative mediation theory and the legal concept ‘the best interests of the child’, I explore and compare the understandings of these concepts as they apply to family mediation. This includes a discussion of the advantages and disadvantages of facilitative as well as evaluative mediation orientations in terms of protecting the best interests of the child. Finnish court-connected family mediation is a combination of both mediation orientations, and the mediator is obliged to secure the best interests of the child. From a theoretical point of view, this seems to be a challenging combination.Peer reviewe

A ganglioside antigen on the rat pancreatic B cell surface identified by monoclonal antibody R2D6.

In an attempt to identify B cell specific antigens, we have generated a mouse monoclonal antibody, R2D6, which is directed against plasma membranes of rat pancreatic B cells but against no other pancreatic cells. R2D6 crossreacted with mouse and guinea pig B cells, but not with human or dog. The B cell specificity of R2D6 was utilized in fluorescence-activated cell sorting to prepare highly enriched separate populations of viable pancreatic islet B cells and A cells. R2D6 also recognized adrenal chromaffin cells, secretory cells in the anterior pituitary, and the myenteric plexus of the gastrointestinal tract. Trypsin, chymotrypsin, papain, ficin, and pronase had no effect on R2D6-binding to dissociated rat islet cells. However, neuraminidase treatment of intact cells reduced R2D6-binding by 75%. The antigen recognized by R2D6, Ag(R2D6), could be quantitatively extracted from rat islets by dichloromethane/methanol (2:1) and, after drying, was soluble in methanol alone as well as in phosphate-buffered saline. When the dichloromethane/methanol extract (DME) was bound to polyvinylchloride microtiter plates, antigenic activity was retained and remained insensitive to pronase. In this solvent-extracted form, antigenic activity was totally destroyed by neuraminidase. Therefore, sialic acid is either an integral part of, or is related sterically to the binding site (epitope) for R2D6. In high performance thin-layer chromatographs of the DME, developed in 60:40:9 chloroform/methanol/2.5 N ammonia, Ag(R2D6) migrated with a relative mobility (Rf) of 0.54 +/- 0.07 (n = 3), which was a position nearly coincident with the purified brain ganglioside, GD1a. The antigen bound to DEAE-Sephacel, was not inactivated by mild treatment with base (which hydrolyzes phospholipids) and eluted in ganglioside fractions upon C18 Sep-Pak and upon silicic acid chromatography. Hence, the solubility characteristics, enzyme sensitivities, and behavior of Ag(R2D6) in four chromatography systems are consistent with its identification as a ganglioside