Intro

I work with stem cells in the lab, so I want to share the information on that topic at that blog. There are lots of interesting articles and study materials about stem cells on the web that's why I'm trying to gather them all here.
Showing posts with label mice. Show all posts
Showing posts with label mice. Show all posts

9/02/2012

Another one stem cell fraud

Wired news... Stem cell research becomes a strange place... Here's some recent events:

Shane Mayack, a former post-doc in Harvard lab of Amy Wagers, a rising star in the stem cell field, has been sanctioned by the Office of Research Integrity for misconduct.
Mayack, who has defended her actions on this blog as honest error — albeit sloppiness — and has not admitted to wrongdoing, must undergo supervision if she receives any federal grant funding over the next three years, under the voluntary agreement.
Here’s the notice, which appeared in the Federal Register this week (and which theBoston Globe was first to report):

Based on the report of an investigation conducted by the Joslin Diabetes Center (Joslin) and additional analysis conducted by ORI in its oversight review, ORI found that Dr. Shane Mayack, former postdoctoral fellow, Department of Developmental and Stem Cell Biology, Joslin, engaged in research misconduct in research supported by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), grants T32 DK07260–29 and P30 DK036836 and the 2008 NIH Director’s New Innovator Award Program grant DP2 OD004345–01.
ORI found that Respondent engaged in research misconduct involving two (2) published papers:
• Mayack, S.R., Shadrach, J.L., Kim, F.S., & Wagers, A.J. ‘‘Systemic signals regulate ageing and rejuventation of blood stem cell niches.’’ Nature 463:495–500, 2010.
• Mayack, S.R., & Wagers, A.J. ‘‘Osteolineage niche cells initiate hemotopoietic stem cell mobilization.’’ Blood 112:519–531, 2008.
As a result of Joslin’s investigation, both Nature 463:495–500, 2010 (hereafter referred to as the ‘‘Nature paper’’) and Blood 112:519–531, 2008 (hereafter referred to as the ‘‘Blood paper’’) have been retracted by the corresponding author.
Specifically, ORI found that:
• Respondent falsely represented von Kossa-stained bone nodule images in two (2) published papers:
Figure 2B in the Blood paper was copied from an unrelated published experiment in Figure 3, J Orth Surg Res 1:7, 2006, and was used to falsely represent Respondent’s own experiment for bone nodules formed in cultured osteoblastic niche cells.
b. Figure S2c in the Nature paper was copied from an online image for an unrelated experiment (at http://skeletalbiology.uchc.edu/30_ResearchProgram/304_gap/3042_Lineage%20in%20Vitro/3042_01_aCellCult.htm#mCOB) and was used to falsely represent Respondent’s own experiment for bone nodules formed in osteoblastic niche cells from young and aged mice.
• Respondent falsely represented eight (8) flow cytometry contour plots as different experimental results by using identical plots but with different labels and different numerical percentages.
Specifically, the following contour plots in the Blood paper, the Nature paper, an earlier version of the Nature paper submitted to Science (hereafter referred to as the ‘‘Science manuscript’’), and a July 2008 PowerPoint presentation were identical but were labeled differently:
a. Panels 4 and 2 in Figure 6C, Blood paper, and panels 1 and 2, respectively, in supplementary Figure 3b, Nature paper
b. Panel 3 in Figure 6C, Blood paper, and panel 1 in Figure 2, July 2008 PowerPoint presentation
Panels 1 and 2, Figure 2b, Science manuscript, and panels 2 and 3, respectively, in Figure 2, July 2008 PowerPoint presentation
Panels 2, 3, and 4, supplemental Figure 4A, Blood paper, and panels 3, 1, and 2, respectively, in Figure 4B, Science manuscript
Both the Respondent and HHS want to conclude this matter without further expenditure of time or other resources and have entered into a Voluntary Settlement Agreement to resolve this matter. Respondent neither admits nor denies ORI’s finding of research misconduct. This settlement does not constitute an admission of liability on the part of the Respondent.
Nearly two years have passed since we first wrote about Mayack. At the time, Wagers’ group had just retracted a 2010 Nature paper — with a notable exception: Mayack refused to sign the notice, nor did she sign the notice for the retraction of the Blood paper, which appeared in late 2011.
As she wrote on this blog:

… the readers of Retraction Watch are no doubt aware that in October 2010, a paper that I co-authored was retracted fromNature and a notice of concern was posted regarding a second paper published in Blood.
So, what went wrong?
The answer to that question begins with the fact that errors, not fabrications, were made in assembling figures for these manuscripts. I am likely the one who made these errors.
Mayack reiterated that position in a comment, through her attorney, to us today:

I remain deeply sorry to the scientific community for mistakes made during the preparation of figures corresponding to some of the work I performed as a postdoc at Harvard Medical School. These were mistakes in representation and presentation of the data, as corroborated by ORI’s findings of ‘falsely presented’, and were not due to fabrication, falsification, or plagiarism of scientific results. I am deeply committed to moving forward and strive to contribute positively to the advancement of science, which has always been my utmost interest.
Wagers recently received tenure.

http://retractionwatch.wordpress.com/2012/08/29/ori-finds-harvard-stem-cell-lab-post-doc-mayack-manipulated-images/ 

1/22/2012

Sperm from the Artificial Testicle!

Stem cell researchers are going to develop in vitro an important part of male's organism - testicle with sperm! More about the event was written by: Rachael Rettner, MyHealthNewsDaily Staff Writer
Published: 01/18/2012 05:20 PM EST on MyHealthNewsDaily

Researchers in California hope to become the first in the world to build an artificial testicle that produces human sperm. Such a device could allow infertile men to conceive children.

While recent studies have shown it's possible to treat infertile male mice by producing sperm using stem cells from the mouse, the same has not been done for humans, said researcher Dr. Paul Turek, director of the Turek Clinic, a men's health medical practice in San Francisco.

Using a newly received government grant, Turek and his fellow researchers hope to develop a human "sperm-making biological machine," he said.

Unlike a non-sperm-producing prosthesis — a saline-filled implant for men missing a testicle — the device will not be designed to resemble a testicle. Instead it will most closely resemble a cylindrical bag a few inches long, Turek said, creating a final product that looks something like a transparent, over-sized Tootsie Roll.

12/26/2011

Nasal Stem Cells


Australian scientists have shown for the first time in mice that nasal stem cells injected into the inner ear have the potential to reverse or restore hearing during early onset sensorineural hearing loss.

Sensorineural hearing loss occurs when hearing cells in the cochlea lose their function. Frequently inherited, and usually starting during infancy and early childhood, the condition can slow a child’s development and lead to speech and language problems.

Drs Jeremy Sullivan, Sonali Pandit and Sharon Oleskevich from Sydney’s Garvan Institute of Medical Research, found that stem cells appear to release ‘factors’, or chemical substances, that help preserve the function of cochlear hearing cells, without the stem cells becoming part of the tissue of the inner ear. Their findings are published in STEM CELLS, now online.

“We are exploring the potential of stem cells to prevent or restore hearing loss in people,” said project leader Dr Sharon Oleskevich.

“The mice we are using have a very similar form of childhood deafness to their human counterparts – except, of course that mouse years are shorter. So a mouse will tend to lose their hearing within 3 months, where a person might take 8 years.”

“We are encouraged by our initial findings, because all the mice injected with stem cells showed improved hearing in comparison with those given a sham injection. Roughly half of the mice did very well indeed, although it is important to note that hearing was not completely restored to normal hearing levels.”

Adult human nasal stem cells were used in the procedure, because they are plentiful, easy to obtain and unspecialised (so have the ability to self-renew for long periods, as well as differentiate into cells with a variety of functions).

The same group of scientists has shown in previous publications that stem cells can also be used to improve hearing in noise-induced hearing loss – a condition that affects both young and older people.

It has taken 5 years to reach the current stage of research, and scientists anticipate that it will take a further decade at least for the findings to benefit people.

Acknowledgements
This research was supported by the Fairfax Foundation and the Australian Deafness Research Foundation. We received much help from ear surgeons at St. Vincent's Hospital, in particular Dr John Tonkin and Professor Paul Fagan. Also from Professor Alan Mackay-Sim, Director of the National Adult Stem Cell Research Centre at Griffith University in Brisbane, who supplied the stem cells used in the project.

Contact: Alison Heather, Science Communications Manager
, Tel: +61 2 9295 8128, Email: a.heather (a) garvan.org.au

Source: The Garvan Institute of Medical Research

12/25/2011

A new study published in Nature reports that scientists have been able to grow working pituitary glands from embryonic stem cells from mice

The pituitary gland is a pea-sized endocrine gland at the base of the brain and secretes different hormones including Human Growth Hormone, or HGH and thyroid-stimulating hormone, or TSH. The release of these hormones plays a role in things such as growth, blood pressure, pregnancy and thyroid function. Inadequate release of certain hormones by the pituitary gland can lead to various hormone disorders.

The team of researchers, led by Dr. Yoshiki Sasai from the RIKEN Centre for Developmental Biology in Kobe, Japan has created a way to grow these little organs using embryonic stem cells from mice. Using a three dimensional culture, the team arranged the mouse stem cells in a way that mimicked the way a pituitary gland grows naturally in the embryo.

When the pituitary gland grows in the embryo, it is made from two different tissue types in the brain. Where these two different tissues come together is where the pituitary gland forms. The researchers set up the culture so these two tissues would come together similar to the way they do in the brain. The fold of tissue known as Rathke’s pouch formed naturally and grew into the pituitary gland. This pituitary gland took three weeks to grow and included all the cell types that are found in a normal pituitary gland.

The researchers then transplanted the tissue into mice that had pituitary problems and the hormone levels soon returned to normal.

While these pituitary glands were created with embryonic stem cells, the researchers believe they can use the same process successfully with stem cells taken from adults and avoid possible ethical concerns with the use of embryonic stem cells.

Research is planned to develop human pituitary glands though Sasai says that will take another four to five years. If successful, these lab-grown pituitary glands could be used to replace ones that have been damaged or do not function properly.

More information: Self-formation of functional adenohypophysis in three-dimensional culture, Nature (2011) doi:10.1038/nature10637

Abstract
The adenohypophysis (anterior pituitary) is a major centre for systemic hormones. At present, no efficient stem-cell culture for its generation is available, partly because of insufficient knowledge about how the pituitary primordium (Rathke’s pouch) is induced in the embryonic head ectoderm. Here we report efficient self-formation of three-dimensional adenohypophysis tissues in an aggregate culture of mouse embryonic stem (ES) cells. ES cells were stimulated to differentiate into non-neural head ectoderm and hypothalamic neuroectoderm in adjacent layers within the aggregate, and treated with hedgehog signalling. Self-organization of Rathke’s-pouch-like three-dimensional structures occurred at the interface of these two epithelia, as seen in vivo, and various endocrine cells including corticotrophs and somatotrophs were subsequently produced. The corticotrophs efficiently secreted adrenocorticotropic hormone in response to corticotrophin releasing hormone and, when grafted in vivo, these cells rescued the systemic glucocorticoid level in hypopituitary mice. Thus, functional anterior pituitary tissue self-forms in ES cell culture, recapitulating local tissue interactions.

© 2011 PhysOrg.com

Thnx to http://medicalxpress.com/news/2011-11-pituitary-glands-embryonic-stem-cells.html for the article
Elleven%20Project