The Genetizen

Genetizen

Advances in genetics and biotechnology are impacting society in provocative ways. The Genetizen is written by a select group of scientists, bioethicists, and healthcare professionals who provide you with expert analysis and commentary on many important issues.

Disclaimer: Opinions expressed in blog postings may or may not reflect the opinions of Geneforum. In addition, the content provided here is purely informational and not a substitute for advice from your personal physician.



Bone marrow transplant 6

Potential risks with bone marrow transplants

A bone marrow transplant is a potentially dangerous procedure that is not to be undertaken lightly. To make matters more difficult, bone marrow transplants are most effect when undertaken early in the course of a patient’s disease. At this point, the patient has less cancer and the disease hasn’t had a chance to become resistant to therapy. However, the significant risks that come with bone marrow transplants make physicians less comfortable about mandating this treatment so early in the disease when other, less invasive treatments might be equally effective.

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Using embryonic stem cells without destroying embryos?

We interrupt the most-thrilling recounting of bone marrow transplant details to bring you news of the latest fig leaf. According to the Washington Post, a thin fig leaf is something designed to take the attention from the ethical dilemmas of possibly approving more federal funding of embryonic stem cells by proposing an alternative way to get pluripotency without asking when does life begin?

The most recent previous attempt was a suggestion that cells could be removed from an embryo and used to develop embryonic stem cells without destroying embryos.

Today is the report that fusion of an embryonic cell with a skin cell resulted in reprogramming of the skin cell to its embryonic state. Wonderful! So, at least three immediate problems jump to mind:

  • Wasn't one of the two cells an embryonic stem cell? How does fusing it with another cell avoid using embryonic stem cells? The Harvard crew used one acceptable embryonic line and one newly developed line for parallel experiments. I don't know whether both experiments succeeded.
  • Human cells with just one small extra chromosome (the 21st) are terribly mixed up. So far, I haven't heard of any successful tetraploid (two times a normal set of chromosomes) humans running around.
  • The existing embryonic stem cell lines (about 9-20 left depending on the source you read) are all presumably contaminated with the mouse cells used to grow them. Are these cells still around?

Anyway, it seems like an interesting ploy to deal with the stem cell issue in the public eye. Keep adding alternatives likely to be successful or not and no one will know what to do. Again, the more YOU learn, the better informed your opinion will be.

Your comments are very welcome!!

Marie Godfrey, PhD

Genetizen's blog

Bone marrow transplant 5

Potential benefits of bone marrow transplants

Sorry, folks, no real numbers here. I’ll keep searching.

Bone marrow transplantation has varying degrees of success, particularly when the donation does not come from the patient or an identical twin. Allogeneic transplantation is more likely to be effective in younger people. After the age of 30, vulnerability to graft–versus–host disease (GVHD) rises rapidly, especially in those between age 40 and 55.

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Bone marrow transplant 4

After the bone marrow transplant procedure

Immediately after the transplant, patients usually remain in the hospital under close supervision. Patients are closely watched until testing reveals adequate levels of white blood cells and platelets. Once the transplanted cells enter the patient’s bloodstream, they travel to the marrow and begin to produce new white blood cells, red blood cells and platelets. This process is known as engraftment, and it usually occurs two to four weeks after the transplant procedure. A physician can detect engraftment by regularly checking blood counts. Patients will also be monitored to ensure that:

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Bone marrow transplant 3

Harvesting donor stem cells

Before a transplant can occur, donor stem cells are most often harvested from the marrow—the liquid center—of the hip bone. In rare cases, the breastbone will be used. The donor is given a general anesthetic (which puts the patient to sleep) or a regional anesthetic (which numbs all feeling below the waist). A needle is inserted through the skin and into the hip bone and the stem cells are then drawn out of the bone. Approximately 100 to 200 needle punctures are needed to remove 500 to 1,000 cubic centimeters (1 to 2 pints) of marrow. This process takes about an hour.

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Bone marrow transplant 2

This blog entry continues a discussion of the elements of the special type of stem cell transplant known as bone marrow transplant. Many of the procedures will be similar for other kinds of stem cell transplants. Most of the information here is adapted from http://cancer.healthcentersonline.com/bloodbonecancer/bonemarrowtransplants3.cfm

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Bone marrow transplant 1

This blog entry begins a series of entries related to the class of stem cell therapy typically referred to as bone marrow transplant or stem cell rescue. The information here is taken, with only minor changes, from CancerHealthOnline (http://cancer.healthcentersonline.com/bloodbonecancer/bonemarrowtransplants.cfm )

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Success in stem cell treatments usually means stem cell rescue

My apologies to those who have been watching for a new blog entry. I've been battling pneumonia and unable to think coherently. I hope I'm recovering now.

Meanwhile, I discovered that the link from the Geneforum home page to the Genetizen blog does not show all the entries. Please check on the right of the screen on the home page for anything you may have missed. My apologies to those who think the last entry was June 1; I didn't intend to become part of the many blogs that started and promptly died. I just have trouble keeping my log on and passwords straight.

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Ignorance and confusion

This morning’s Google Alerts included a very interesting article by Elizabeth M. Whelan, Sc.D, MPH, founder and president of the American Council on Science and Health. She states,

…the passage of legislation to approve federal funding of ESC [embryo stem cell research] is still not certain, but nearly everyone hearing of the Frist move was either (a) very encouraged, envisioning the United States finally getting into the race to derive life-saving therapies using embryonic in addition to adult stem cells, or (b) very discouraged, proclaiming that even normally "pro-life" politicians are now succumbing to surging popular support for all forms of stem cell research.

read more | mgodfrey39's blog

Leads on question of adult vs. embryonic stem cell potential

Since I have not yet created a template for my blog entries, I return to old ones to make the font, spacing, etc. the same. Today, I happened to stumble on my July 3 blog and see that I have been wrong about Frist's changes of mind and when they occurred. His most recent to back the removal of federal funding restrictions on embryonic stem cell research is his second switch, as I have been saying. But, the first switch from support to banning occurred back in 2001 after Bush restricted federal funding, not in April of this year. I had the date incorrect.

This morning's (6 August 2005) Google Alerts brought me an article from WorldNet Daily, Grants Pass Oregon, written by Kelly Hollowell, JD, PhD, Senior Strategist at the Center for Reclaiming America. The alert read: A detailed list of supporting references is available on request to my e-mail address below, as is a list of adult stem cell applications for 65 human diseases. Had another portion of the article been chosen for the alert, such as her quotes from Frist, I might never have checked out the article. As it was, I read it finding a discussion countering Frist's use of unique to describe embryonic stem cell capabilities. Hollowell states:

According to more than 15 recent publications in leading and peer-reviewed scientific journals, adult stem cells have the same pluripotency and/or capacity to multiply as embryonic stem cells.

The most recent and groundbreaking publication, by Dr. John Huard, director of the Growth and Development Laboratory at Children's Hospital of Pittsburgh, confirms that adult stem cells have the same ability as embryonic stem cells to multiply. This publication appears in the July 2005 edition of Molecular Biology of the Cell. The paper is appropriately under consideration for Molecular Biology of the Cell paper of the year.

Other data clearly demonstrate the ability of adult stem cells to form heart, liver, kidney, muscle, brain, nerve, insulin-producing, hair, skin, lung, retina, intestinal and spleen cells. The data also demonstrate that adult stem cells have the ability to regenerate damaged tissue.

I responded to the article immediately, adding some comments of my own, and requested the list of references, which she promptly sent. Of course, I also invited her to check out Geneforum and add her comments to the discussion.

I'll be reviewing as many articles as I can, so I can digest the information she references and bring you a summary of what I find. These references are a perfect source for my last blog entry question: how do adult stem cells and embryonic stem cells compare in potential? Unfortunately, searching MedLine or Google scholarly for successful stem-cell treatments has been frustrating. Thank you, Dr. Hollowell.

Marie Godfrey, PhD

mgodfrey39's blog

Get your opinion in shape and share it

There are more than enough versions of today’s announcement by Bill Frist that he has changed his mind and will now not only allow the Senate to discuss federal funding of stem cell research but will also support at least a change in President Bush’s restrictions on that funding. There are also plenty of responses to Frist’s announcement. So. while Congress is in August recess, it’s time for us to jump into the fray and 1) clarify our own opinions on stem cell research in general and federal funding in particular, 2) add to our knowledge based on developments and progress—or lack thereof—around the world, and 3) express ourselves.

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New bill introduced in House

On June 30, Representative Bartlett (MD) introduced H.B.3144 into the House of Representatives. The bill’s purpose is to amend the Public Health Service Act to provide for a program at the National Institutes of Health (NIH) to conduct and support research in the derivation and use of human pluripotent stem cells by means that do not harm human embryos, and for other purposes. The bill would appropriate $15,000,000 in fiscal year 2006, and such sums as may be necessary for each of the fiscal years 2007 through 2010

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All over but the waiting?

I get about 7 or 8 updates a day on stem cells, but can’t always read them all. Part of the reason is a glitch in my e-mail boxes that lets mail come in but not function properly. My main mailbox doesn’t read hyperlinks. So, it’s taken me a while to discover an article that preceded the update I received today headlined, “Stem cell scientists mourn Frist’s change.”

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Interpreting stem-cell research

In general terms, a stem cell is any cell that can multiply indefinitely and has the capacity to differentiate into more than one cell type. A stem-cell line is a group of stem cells in laboratory conditions (i.e., in vitro), continually producing new cells of the same type. Stem cells can be derived from embryos, from adult cells, from umbilical cords that are discarded after babies are born, and from human placentas. Under special laboratory conditions, stem cells can be encouraged to produce a variety of human cell types, including nerve cells, liver cells, and heart cells.

To more accurately interpret media references to stem-cell research ask the following questions:

What animal is involved? Research conducted with mice often provides insight into human systems and the research has fewer moral and regulatory issues attached. Because of current limitations in the U.S., federally-funded studies on embryonic stem cells can only be conducted with non-human animals or existing stem-cell lines. There are no limitations on privately-funded studies other than the restriction that cloning cannot be used as a source of stem cells. Research is also being conducted with tissues cultured from humans or other organisms.

Where is the work being done? Much of the current human embryonic stem-cell research is being conducted outside of the U.S. Inside the U.S., work on non-adult stem cells is limited to the few institutions who have, or can obtain, existing embryonic stem-cell lines. There are currently no U.S. limitations on non-embryonic stem-cell research, other than those already in place for any human clinical study.

What was the source of the cells?

Non-embryonic, or adult, stem cells are relatively undifferentiated cells removed from an adult and allowed to multiply in vitro. Bone marrow cells, grown in vitro before being injected into a recipient, are one type of stem cell. Non-embryonic stem cells have been tested in the treatment of cancer, Crohn's disease, and multiple sclerosis.

Embryonic stem cells are cells harvested from a special part of a late blastocyst --a layered ball of cells resulting from multiplication of a fertilized egg. Under special conditions, embryonic stem cells can develop in vitro into any tissue of the body. Muscle, nerve, and heart (cardiac) tissues have been grown this way. While the entire blastocyst, under proper conditions, can develop into a human being, embryonic stem cells cannot.

Umbilical cord blood contains neonatal stem cells. These cells are capable of differentiating into various cell types; such as hematopoietic cells (blood and immune system-forming cells), mesenchymal cells (muscle, cartilage, bone and fat cells), and neural cells (brain and central nervous system cells). These properties of cord blood stem cells are similar to those shown by embryonic stem cells. However, unlike embryonic stem cells, umbilical cord blood stem cells are abundant, easily collected and are non-controversial.

Who was the source of the genetic material? Non-embryonic stem cells can come from the same person who later receives the injected stem cells (autologous transplant), a closely related person (allogenic transplant), or an immunologically matched but unrelated person (Matched Unrelated Donor or MUD transplant). Syngenic bone marrow transplants are performed from one identical twin to the other. Prior to receiving the newly grown cells, the recipient is treated to decrease their own immune system's cells to as few as possible. After receiving transplanted cells, the recipient may be given drugs to prevent rejection of the new cells and possible graft-versus-host disease. Once begun, anti-rejection drugs must be continued throughout the recipients life. Embryonic stem cells can be harvested from an embryo that has developed to the blastocyst stage (14 days and about 150 cells) from a naturally-fertilized egg, an artificially-fertilized egg, or an egg whose genetic material was replaced by genetic material from another cell. Genetic material from the intended stem-cell recipient can be used to replace genetic material of a fertilized egg.

Stem cells can also be identified by the terms pluripotent, totipotent, and multipotent:

Totipotent stem cells form when a fertilized egg first divides. Totipotent stem cells can develop into a complete individual.

Pluripotent stem cells are also called embryonic stem cells. A few days after a fertilized egg divides, the totipotent stem cells form a blastocyst, or a ball of cells. The inner layer of this blastocyst contains pluripotent stem cells, which are capable of developing into any tissue in the body. Pluripotent stem cells cannot, however, become a complete individual.

Multipotent stem cells are sometimes called somatic or adult stem cells. These stem cells are found in mature tissue and are maintained by the body to replace worn out cells in tissues and organs. Stem cells from bone marrow, called hematopoietic stem cells, form the various kinds of blood cells. Neural stem cells form the brain and central nervous system. Mesenchymal stem cells form fat, bone, muscle and cartilage.

Marie Godfrey, PhD

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Finding hidden words

Knowing a lot about genetics doesn’t always give you insight into the decision-making process of the US Legislature. I now have Google alerts that tell me—many times a day—when the phrase “stem cell” appears in the news and I have daily international alerts from an ethics and the law publication. I also turn on my tv each day to the Senate and House proceedings. Figuring out how the Senate operates on a daily basis requires more background than my high school civics class gave me. None of these really help me keep track of what’s happening in Congress with the stem-cell issue, so I’ve bookmarked the 109th Congress and check details each day.

I have found that reading the daily digest isn’t enough and the “official” update on each bill only covers “major” actions—ignoring additions of sponsors or programmed, but unscheduled, speeches on the floor of the Senate or House. So, I’ve finally moved to http://thomas.loc.gov/home/r109query.html and querying “stem cell” by specific date and searching the extended remarks. This helps, but—as come would say—not much. How I wish people would learn to begin their remarks with specifics! You can view a whole page of the beginning of remarks, followed by ….. indicating that the words continue, and never figure out what the topic is.

The energy bill (HB 6) is currently on the floor of the Senate and more confirmation hearings are scheduled for Monday, the 20th. Meanwhile, stem cells are prominent in local news across the world. Perhaps I’ll look for awhile at what states here and countries elsewhere are doing.

Marie Godfrey, PhD

mgodfrey39's blog