Slide #19 of talk by Michel van der Burg at the 4th ESOT congress in Barcelona (Spain) Nov 1989 on the paper ‘Pancreatic Islet Isolation With UW Solution • A New Concept’ (1,2). Details of this talk were posted recently (2) with a scan of a paper print of slide #19 – slighly cropped with printing.
Here the full image of the original slide, scanned by Kodak PhotoCD in 1994, with minor color correction added (20250103_1) in this post.

This ‘Slide #19’ shows the final dithizone stained sample of the UW-isolated islets after dextran density gradient purification — a micrograph made April 18, 1989 , the second islet isolation experiment performed using the UW-Solution as the isolation solution.

In the lab journal of the first isolation experiment with UW-Solution, Wednesday April 12th 1989, I noted on the final purified islet preparation : ‘handpicking for encapsulation was not necessary: ​​preparation more than 90% pure ( translated from dutch : “handpicken voor inkapseling was niet nodig: preparaat meer dan 90% zuiver”)’.

‘Handpicking’ of islets had been done at the start of our islet lab in 1985-1987 for counting rodent islets in cell culture dishes, and monitoring islet insulin secretion in tubes (3). Soon, ‘handpicking’ was no longer needed , when monitoring the insulin secretion of isolated islets in perifusion chambers (4,5). However, the handpicking method was used again in a pilot study on encapsulation of islets in 1989 by medical student Joost Clemens (6). Joost had just started on this research project, and was assisting me with islet ‘counting’ (yield and purity assessment) in the ‘duplo’ samples from this first series of UWS isolations.

Macro photography (Photo paper print, September 1987, AVC, Leiden University) of the aspiration of isolated canine pancreatic islets, in a suspension still contaminated with exocrine pancreatic fragments, at the tip of a hand blown glass handpicking pipette (custom made at the Leiden University) collected and transferred into tubes for monitoring insulin secretion the first year of pilot work in the Leiden islet laboratory (4).

Notes

1) Pancreatic Islet Isolation With UW Solution • A New Concept • Michel van der Burg • Miracles.Media • @1MEMO 20241224 • URL https://michelvanderburg.com/2024/12/24/pancreatic-islet-isolation-with-uw-solution-a-new-concept-20241224/

2) Pancreatic Islet Isolation in UW Solution & Transplantation • ESOT 1989 Talk • Michel van der Burg • Miracles.Media • @1MEMO 20241229 • URL michelvanderburg.com/2024/12/29/

3) Lucky #1 Islet • 20240811 • Michel van der Burg • michelvanderburg•com

4) Cradle of Islet Transplants • 20240829 • Michel van der Burg • michelvanderburg•com

5) Monitoring pancreatic islets in perifusion • 20240911 | Michel van der Burg | michelvanderburg•com

6) Joost A.M. Clemens (MSc student in Medicine) at the Department of Biomaterials (Prof. dr K. de Groot) and Department of Surgery of the Leiden University (Michel van der Burg , Hein Gooszen). Pilot study of the encapsulation of dog islets using the alginate polylysine and poly-HEMA-phospate method (1989).
At that time , both the Biomaterials department and the Islet Lab of the Surgery department were housed in the building of the Cell Biology department of the Leiden University Hospital (AZL, now LUMC). Below a portrait snapshot I took of Klaas de Groot at a Garden party organized in 1989 by the Department of Cell Biology, Leiden University.

Citation info : Pancreatic Islets UWS Series 1989 • Kodak PhotoCD • Michel van der Burg • Miracles.Media • @1MEMO 20250103 • URL michelvanderburg.com/2025/01/03/