Birthdating cells

posted by | Leave a comment

Nevertheless, as Spalding and colleagues point out, there are plenty of tissue banks with archived material which will always be useful.—Tom Fagan About 40 years ago, Joseph Altman and his colleagues used the 3H-thymidine autoradiographic method to birthdate cells in the brains of adult rats and cats, and reported evidence for neurogenesis in the olfactory bulb, hippocampus, and neocortex (1-5).These findings were corroborated and extended by Michael Kaplan and his colleagues by combining 3H-thymidine autoradiography with electron microscopy (16-19).Bromodeoxyuridine (5-bromo-2'-deoxyuridine, Brd U, BUd R, Brd Urd, broxuridine) is a synthetic nucleoside that is an analog of thymidine.Brd U is commonly used in the detection of proliferating cells in living tissues.Therefore, a group of microorganisms may respond to a C source but go undetected using this technique.Additionally, this technique is biased towards identifying microorganisms with A- and T-rich genomes.But the almost tenfold increase in atmospheric C14 that peaked around the mid-1960s has been followed by a rapid decline since the nuclear test ban treaties and the cessation of high-yield, above-ground nuclear tests.

Now, Jonas Frisen and colleagues at the Karolinska Institute in Stockholm have taken advantage of this spike in C14 to devise a method to date the birth of human cells.Because this test can be used retrospectively, unlike many of the current methods used to detect cell proliferation, and because it does not require the ingestion of a radioactive or chemical tracer, the method can be readily applied to both in vivo and postmortem samples of human tissues.In today’s Cell, Frisen and colleagues report how they used the dating method to dismiss the possibility that neurogenesis takes place in the adult human cortex.The authors first established that there is a relationship between the C14 content of DNA and the atmospheric C14 in the local area when that DNA was made.Unlike many other macromolecules in a cell, DNA is chemically stable once laid down, so its C14 levels are not expected to change even if the DNA ages.

Leave a Reply

  1. muslim dating in europe 29-May-2017 08:49

    You’ll learn about most popular, as well as good and straightforwardly poor Asian cams, Oriental male and female models, etc.

  2. Free non sighn up sexy naughty online chat 09-Mar-2017 04:15

    Justin and Sam were allured by their charming young teacher from the very first lecture, but all their awkward attempts to seduce her failed, so they decided to enjoy her gorgeous body against her will.

Adult dating sites without registration