 |
| Jim Linzell, June 1974 Photographed at Babraham by Alec Bangham |
It was in May 1948 that Jim Linzell (1921-1975) realised he had, just like Keith Richardson, stained myoepithelial cells while looking for nerve fibres in the mammary gland.
Linzell had escaped veterinary practice and was working for a PhD in the University of Edinburgh’s physiology department. He had qualified as a vet in London but found veterinary practice frustrating and unrewarding in that he lacked the time to be thorough while having to undertake jobs that technicians were perfectly capable of doing. He changed direction by going to Edinburgh to work under Professor Ivan de Burgh Daly FRS (1893-1974). He was funded by an Agricultural Research Council (now morphed into the BBSRC) research traineeship. He told Daly that he would like to work on the uterus and placenta but Daly told him to find out everything about the anatomy and physiology of the mammary glands in as many species as he could; this he did until he died at the age of 54.
Linzell did not like Edinburgh. Cold, dank and unfriendly was how he described it. Jim and Audrey, together with their two sons, lived in a flat relatively near the university. He published a note in Veterinary Record which gave his address: 7 Blackwood Crescent. His trenchant views on that flat, the landlord, the neighbours and the inhabitants of Edinburgh were expressed many times in later years whenever Edinburgh was mentioned. He would be horrified by its current valuation of £210,000.
 |
| The Linzell family had a flat in this house in Edinburgh Google Street View |
But Jim was not stuck in Edinburgh. A great deal was happening to Daly and the future of agricultural research. During the Second World War it was realised that the lack of progress in increasing food production was caused by lack of knowledge of how animals work. To this end, Daly was given the job of setting up a new research institute. He found a run-down stately home for sale near Cambridge and set about building laboratories, animal houses and housing for staff. Staff were appointed ahead of space becoming available and Linzell became one of the first members of staff of what is now the Babraham Institute on 1 October 1948, albeit based for a time in Edinburgh. Then, a temporary measure, Daly converted rooms in Babraham Hall into laboratories and a wash-house to hold Linzell’s goats. Linzell was one of the first scientists on site in 1950 as Daly eviscerated his old department in Edinburgh by appointing members of staff to Babraham posts.
It was in Edinburgh that Linzell found he had revealed myoepithelial cells in the mammary gland of cats. He was studying the role of nerves in controlling blood flow by classical physiological and histological techniques. In his first paper, published in Journal of Anatomy in 1952—Jim never rushed into print—he confirmed all the findings of Richardson. He also tried various methods of silver staining which were all notoriously capricious but extended his work beyond one species. He showed clearly the presence of myoepithelial cells in cat, dog, rabbit, rat, goat, and human mammary glands.
An important additional finding was that the myoepithelial cells have no connexions to the nervous system, thereby refuting one suggestion that the milk-ejection reflex was a pathway composed entirely of nerves.
He then went further. By observing the living gland he saw contraction of the myoepithelial cells in mouse, rat, guinea pig and rabbit and was able to study what caused them to contract and thereby expel milk. Oxytocin dropped onto the gland, of course, worked. So did direct electrical stimulation was one would expect with a muscle but stimulation of nerves in the region had no such effect. Sometimes, light mechanical stimulation was enough to do the trick.
Linzell’s observations provided the final link in the chain for the neuroendocrine milk-ejection reflex.
 |
| Two figures from Linzell's 1955 paper. On the left the alveoli can be seen full of milk. When oxytocin was dropped on the gland (right) the alveoli contracted and milk was driven into the duct (D) |
Linzell’s observations on the living myoepithelium were presented to the Physiological Society at its meeting of 18-19 December 1953. That was his first appearance before the Society, a year after his election as a member. Presenting a paper was a daunting experience because right through the 70s and into he 80s there was a phalanx of Nobel prizewinners in the audience. Discussion was often fierce and every word in the circulated abstract had to be agreed before a vote was taken on whether or not the paper should be accepted for publication in Journal of Physiology. Because the paper was refereed by attendees it could be included in reviews that demanded reference only to refereed papers. For some reason I do not understand or agree with that system was dropped by the Physiological Society in the early years of the present century. Sometimes, if all the material had been published in the Proceedings, it was not necessary to clutter the literature with a full paper. However, Linzell had covered a lot of ground in his observations and a full paper appeared in Journal of Physiology in 1955.
Neither Keith Richardson nor Jim Linzell took any further part in work on the milk-ejection reflex.
In the past I have used the history of the milk-ejection reflex to illustrate the fact that many advances in human physiology and medicine have come from fundamental research funded as part of agricultural research.
But there remain many unanswered questions about myoepithelial cells in exocrine glands—not in the mammary gland but elsewhere in the body.
Linzell JL. 1952. The silver staining of myoepithelial cells, particularly in the mammary gland, and their relation to the ejection of milk. Journal of Anatomy 86, 49-57.
Linzell JL. 1954. The contractility of the alveoli of the mammary gland. Journal of Physiology 123, 32P.
No comments:
Post a Comment