By the 16th century, beaver-felt hats were all the rage in Europe. The hair of the beaver also changed the course of history. The descendant of an English wool merchant named John Barton placed a sign in the window of his “fair stone house” that exulted, “I thank God and ever shall/It is the sheepe hath payed for all.” The wool trade created the fortunes of such bankers as the Florentines, whose patronage of Michelangelo gave us the Sistine Chapel’s painted ceiling. English herders raised the best wool, and competed with Flanders to turn it into cloth for the world. Eyelashes remain short because they grow for just 30 days.Īnother mammal’s hair-sheep’s wool-shaped Western culture. A scalp hair shaft will grow for two to six years, allowing humans to wear hair cascading down their backs or in coronas around their heads. Moreover, each type of human hair abides by its own calendar. Unlike animal hair, which grows on a fixed cycle and sheds twice a year, human hair follicles stagger their growth. Just 10 or 20 minutes of walking, scientists have estimated, would have felled upright fur-covered hominids with heatstroke. Stenn begins by explaining why we, of all primates, lost most of our body hair: Our ancestors became naked apes to cool their growing and temperature-sensitive brains, which would suffer a meltdown (that is, brain death) at 107 degrees Fahrenheit. By the end of Hair: A Human History, a reader might even be convinced that hair makes the world go ’round. The former Yale pathologist and dermatologist moves from the evolution of human hair to hair’s effects on culture, psychology, and global trade. Using various techniques, exposure of the “infundibular cysts” by puncturing, piercing, or scratching the skin and, in an approach, covering the exposed cysts with a wound dressing material produced egressing hair follicles.The hair on our heads is just the departure point for this wide-ranging book by Kurt Stenn, M.D. From the “infundibular cysts” hair germs form followed by follicular buds and then pegs which grow asymmetrically to differentiate into cycling mature pilosebaceous structures.

This process involves the aggregation of epithelial cells to form clusters which are sculpted by apoptosis to generate “infundibular cysts”.

In a method of this application dissociated cells, isolated from newborn mouse skin, are injected into adult mouse truncal skin, hair follicles develop. The method serves both as a tool for measuring the trichogenic (i.e., hair growth-inducing) property of cells and for studying the mechanisms dissociated cells employ to assemble an organ.

A method assay for rapidly and reproducibly generating hair follicles from dissociated epithelial and mesenchymal cells is disclosed.

Kurt stenn