all Jonathan Tilly stories

Harvard, MGH researchers track egg cell production to marrow

50443248 — Fri, 20 Jul 2007 15:51:26 -0400

Harvard researchers have found new evidence that female mammals can produce egg cells throughout life and have traced their production out of the ovary and into the bone marrow in findings that could both reshape science's understanding of female reproduction and provide new avenues for treatment of infertility.
In a series of experiments on sterile female mice, researchers from Massachusetts General Hospital (MGH), a Harvard teaching hospital, were able to restore egg production by transplanting bone marrow from fertile mice. The researchers believe that egg stem cells in the donor bone marrow established themselves in the sterile mice and began producing egg cells, also called oocytes.

Harvard, MGH researchers track egg cell production to marrow

70652986 — Mon, 26 Mar 2007 06:21:45 -0400

In a series of experiments on sterile female mice, Massachusetts General Hospital (MGH) researchers were able to restore egg production by transplanting bone marrow from fertile mice. The researchers believe that egg stem cells in the donor bone marrow established themselves in the sterile mice and began producing egg cells. The results are published in the July 29, 2005 issue of Cell.

The research team treated mice with a chemotherapy drug known to destroy eggs but to be less damaging to long-term fertility, and found the ovaries lost 80 percent of their egg cells within 24 hours. Within two months, the ovaries appeared to have fully recovered.

To find the source of egg replenishment, they examined the ovary for a molecule found only on the surface of cells that develop into eggs in the embryo. They found a part of the ovary where blood enters and exits but is devoid of egg cells.

On examining the bone marrow, they found several proteins created only by reproductive cells and by cells developing into reproductive cells.

To test whether they had found the egg stem cell site, they transplanted bone marrow into chemically and genetically sterilized mice. Both sets of mice began growing egg cells in their ovaries.

Cell death in eggs traced to smoking

70652986 — Mon, 26 Mar 2007 05:13:07 -0400

A woman is born with just so many egg cells, called oocytes. When she begins ovulating, she has about 400. Even though that may seem like a lot, considering the few that would ever be fertilized, scientists have found that loss of oocytes influences a woman's health. Early loss of oocytes leads to early menopause and infertility. A study by researcher Jonathan Tilly, Harvard Medical School associate professor of obstetrics, gynecology and reproductive biology at Massachusetts General Hospital, has found that chemicals in cigarette smoke and environmental pollutants can trigger egg loss. "There's a longstanding relationship between smoking and early menopause," Tilly said.