Kunena Site Syndication http://e-biotek.com Sat, 19 May 2012 08:38:14 +0000 Kunena 1.6 http://e-biotek.com/components/com_kunena/template/default/images/icons/rss.png http://e-biotek.com/ en-gb http://e-biotek.com/forum/15-Stem-Cell-Methods/3230-Stem-Cell-Basics.html#3230 http://e-biotek.com/forum/15-Stem-Cell-Methods/3230-Stem-Cell-Basics.html#3230
The NIH developed this primer to help readers understand the answers to questions such as:

What are stem cells?
What are the different types of stem cells, and where do they come from?
What is the potential for new medical treatments using stem cells?
What research is needed to make such treatments a reality?

stemcells.nih.gov/info/basics/defaultpage.asp]]> Stem Cell Methods Sat, 28 Apr 2012 07:50:17 +0000 http://e-biotek.com/forum/15-Stem-Cell-Methods/3230-Stem-Cell-Basics.html#3230 http://e-biotek.com/forum/15-Stem-Cell-Methods/3228-Removing-Barriers-to-Responsible-Scientific-Resear.html#3228 http://e-biotek.com/forum/15-Stem-Cell-Methods/3228-Removing-Barriers-to-Responsible-Scientific-Resear.html#3228 Removing Barriers to Responsible Scientific Research Involving Human Stem Cells

By the authority vested in me as President by the Constitution and the
laws of the United States of America, it is hereby ordered as follows:
Section 1. Policy. Research involving human embryonic stem cells and human
non-embryonic stem cells has the potential to lead to better understanding
and treatment of many disabling diseases and conditions. Advances over
the past decade in this promising scientific field have been encouraging,
leading to broad agreement in the scientific community that the research
should be supported by Federal funds.
For the past 8 years, the authority of the Department of Health and Human
Services, including the National Institutes of Health (NIH), to fund and
conduct human embryonic stem cell research has been limited by Presidential
actions. The purpose of this order is to remove these limitations on scientific
inquiry, to expand NIH support for the exploration of human stem cell
research, and in so doing to enhance the contribution of America’s scientists
to important new discoveries and new therapies for the benefit of humankind.
Sec. 2. Research. The Secretary of Health and Human Services (Secretary),
through the Director of NIH, may support and conduct responsible, scientifically
worthy human stem cell research, including human embryonic stem
cell research, to the extent permitted by law.
Sec. 3. Guidance. Within 120 days from the date of this order, the Secretary,
through the Director of NIH, shall review existing NIH guidance and other
widely recognized guidelines on human stem cell research, including provisions
establishing appropriate safeguards, and issue new NIH guidance on
such research that is consistent with this order. The Secretary, through
NIH, shall review and update such guidance periodically, as appropriate.
Sec. 4. General Provisions. (a) This order shall be implemented consistent
with applicable law and subject to the availability of appropriations.
(b) Nothing in this order shall be construed to impair or otherwise affect:
(i) authority granted by law to an executive department, agency, or
the head thereof; or
(ii) functions of the Director of the Office of Management and Budget
relating to budgetary, administrative, or legislative proposals.
(c) This order is not intended to, and does not, create any right or benefit,
substantive or procedural, enforceable at law or in equity, by any party
against the United States, its departments, agencies, or entities, its officers,
employees, or agents, or any other person.]]> Stem Cell Methods Sat, 28 Apr 2012 07:47:14 +0000 http://e-biotek.com/forum/15-Stem-Cell-Methods/3228-Removing-Barriers-to-Responsible-Scientific-Resear.html#3228 http://e-biotek.com/forum/15-Stem-Cell-Methods/3226-Glossary-of-Stem-Cell.html#3226 http://e-biotek.com/forum/15-Stem-Cell-Methods/3226-Glossary-of-Stem-Cell.html#3226
Astrocyte—A type of supporting (glial) cell found in the nervous system.

Blastocoel—The fluid-filled cavity inside the blastocyst, an early, preimplantation stage of the developing embryo.

Blastocyst—A preimplantation embryo of about 150 cells produced by cell division following fertilization. The blastocyst is a sphere made up of an outer layer of cells (the trophoblast), a fluid-filled cavity (the blastocoel), and a cluster of cells on the interior (the inner cell mass).

Bone marrow stromal cells—A population of cells found in bone marrow that are different from blood cells.

Bone marrow stromal stem cells (skeletal stem cells)—A multipotent subset of bone marrow stromal cells able to form bone, cartilage, stromal cells that support blood formation, fat, and fibrous tissue.

Cell-based therapies—Treatment in which stem cells are induced to differentiate into the specific cell type required to repair damaged or destroyed cells or tissues.

Cell culture—Growth of cells in vitro in an artificial medium for research or medical treatment.

Cell division—Method by which a single cell divides to create two cells. There are two main types of cell division depending on what happens to the chromosomes: mitosis and meiosis.

Chromosome—A structure consisting of DNA and regulatory proteins found in the nucleus of the cell. The DNA in the nucleus is usually divided up among several chromosomes.The number of chromosomes in the nucleus varies depending on the species of the organism. Humans have 46 chromosomes.

Clone— (v) To generate identical copies of a region of a DNA molecule or to generate genetically identical copies of a cell, or organism; (n) The identical molecule, cell, or organism that results from the cloning process.

In reference to DNA: To clone a gene, one finds the region where the gene resides on the DNA and copies that section of the DNA using laboratory techniques.
In reference to cells grown in a tissue culture dish:a clone is a line of cells that is genetically identical to the originating cell. This cloned line is produced by cell division (mitosis) of the original cell.
In reference to organisms: Many natural clones are produced by plants and (mostly invertebrate) animals. The term clone may also be used to refer to an animal produced by somatic cell nuclear transfer (SCNT) or parthenogenesis.
Cloning—See Clone.

Cord blood stem cells—See Umbilical cord blood stem cells.

Culture medium—The liquid that covers cells in a culture dish and contains nutrients to nourish and support the cells. Culture medium may also include growth factors added to produce desired changes in the cells.

Differentiation—The process whereby an unspecialized embryonic cell acquires the features of a specialized cell such as a heart, liver, or muscle cell. Differentiation is controlled by the interaction of a cell's genes with the physical and chemical conditions outside the cell, usually through signaling pathways involving proteins embedded in the cell surface.

Directed differentiation—The manipulation of stem cell culture conditions to induce differentiation into a particular cell type.

DNA—Deoxyribonucleic acid, a chemical found primarily in the nucleus of cells. DNA carries the instructions or blueprint for making all the structures and materials the body needs to function. DNA consists of both genes and non-gene DNA in between the genes.

Ectoderm—The outermost germ layer of cells derived from the inner cell mass of the blastocyst; gives rise to the nervous system, sensory organs, skin, and related structures.

Embryo—In humans, the developing organism from the time of fertilization until the end of the eighth week of gestation, when it is called a fetus.

Embryoid bodies—Rounded collections of cells that arise when embryonic stem cells are cultured in suspension. Embryoid bodies contain cell types derived from all 3 germ layers.

Embryonic germ cells—Pluripotent stem cells that are derived from early germ cells (those that would become sperm and eggs). Embryonic germ cells (EG cells) are thought to have properties similar to embryonic stem cells.

Embryonic stem cells—Primitive (undifferentiated) cells that are derived from preimplantation-stage embryos, are capable of dividing without differentiating for a prolonged period in culture, and are known to develop into cells and tissues of the three primary germ layers.

Embryonic stem cell line—Embryonic stem cells, which have been cultured under in vitro conditions that allow proliferation without differentiation for months to years.

Endoderm—The innermost layer of the cells derived from the inner cell mass of the blastocyst; it gives rise to lungs, other respiratory structures, and digestive organs, or generally "the gut."

Enucleated—Having had its nucleus removed.

Epigenetic—Having to do with the process by which regulatory proteins can turn genes on or off in a way that can be passed on during cell division.

Feeder layer—Cells used in co-culture to maintain pluripotent stem cells. For human embryonic stem cell culture, typical feeder layers include mouse embryonic fibroblasts (MEFs) or human embryonic fibroblasts that have been treated to prevent them from dividing.

Fertilization—The joining of the male gamete (sperm) and the female gamete (egg).

Fetus—In humans, the developing human from approximately eight weeks after conception until the time of its birth.

Gamete—An egg (in the female) or sperm (in the male) cell. See also Somatic cell.

Gastrulation—The process in which cells proliferate and migrate within the embryo to transform the inner cell mass of the blastocyst stage into an embryo containing all three primary germ layers.

Gene—A functional unit of heredity that is a segment of DNA found on chromosomes in the nucleus of a cell. Genes direct the formation of an enzyme or other protein.

Germ layers—After the blastocyst stage of embryonic development, the inner cell mass of the blastocyst goes through gastrulation, a period when the inner cell mass becomes organized into three distinct cell layers, called germ layers. The three layers are the ectoderm, the mesoderm, and the endoderm.

Hematopoietic stem cell—A stem cell that gives rise to all red and white blood cells and platelets.

Human embryonic stem cell (hESC)—A type of pluripotent stem cells derived from early stage human embryos, up to and including the blastocyst stage, that are capable of dividing without differentiating for a prolonged period in culture, and are known to develop into cells and tissues of the three primary germ layers.

Induced pluripotent stem cell (iPSC)—A type of pluripotent stem cell, similar to an embryonic stem cell, formed by the introduction of certain embryonic genes into a somatic cell.

In vitro—Latin for "in glass"; in a laboratory dish or test tube; an artificial environment.

In vitro fertilization—A technique that unites the egg and sperm in a laboratory instead of inside the female body.

Inner cell mass (ICM)—The cluster of cells inside the blastocyst. These cells give rise to the embryo and ultimately the fetus. The ICM may be used to generate embryonic stem cells.

Long-term self-renewal—The ability of stem cells to replicate themselves by dividing into the same non-specialized cell type over long periods (many months to years) depending on the specific type of stem cell.

Mesenchymal stem cells—A term that is currently used to define non-blood adult stem cells from a variety of tissues, although it is not clear that mesenchymal stem cells from different tissues are the same.]]> Stem Cell Methods Sat, 28 Apr 2012 07:44:24 +0000 http://e-biotek.com/forum/15-Stem-Cell-Methods/3226-Glossary-of-Stem-Cell.html#3226 http://e-biotek.com/forum/15-Stem-Cell-Methods/3225-Stem-Cells-and-Diseases.html#3225 http://e-biotek.com/forum/15-Stem-Cell-Methods/3225-Stem-Cells-and-Diseases.html#3225 The Promise of Stem Cells

Studying stem cells will help us understand how they transform into the dazzling array of specialized cells that make us what we are. Some of the most serious medical conditions, such as cancer and birth defects, are due to problems that occur somewhere in this process. A better understanding of normal cell development will allow us to understand and perhaps correct the errors that cause these medical conditions.

Another potential application of stem cells is making cells and tissues for medical therapies. Today, donated organs and tissues are often used to replace those that are diseased or destroyed. Unfortunately, the number of people needing a transplant far exceeds the number of organs available for transplantation. Pluripotent stem cells offer the possibility of a renewable source of replacement cells and tissues to treat a myriad of diseases, conditions, and disabilities including Parkinson's disease, amyotrophic lateral sclerosis, spinal cord injury, burns, heart disease, diabetes, and arthritis.

Have human embryonic stem cells successfully treated any human diseases?

Scientists have been able to do experiments with human embryonic stem cells (hESC) only since 1998, when a group led by Dr. James Thomson at the University of Wisconsin developed a technique to isolate and grow the cells. Although hESCs are thought to offer potential cures and therapies for many devastating diseases, research using them is still in its early stages.

The NIH funded its first basic research study on hESCs in 2002. Since that time, biotechnology companies have built upon those basic foundations to begin developing stem cell-based human therapies. There are currently two active clinical trials using cells derived from human embryonic stem cells, both being conducted by a biotechnology company called ACT. The company has laboratories in Marlborough, Massachusetts and corporate offices in Santa Monica, California. ACT has begun enrolling patients for Phase I (safety and tolerability) clinical trials of two hESC-derived stem cell products:

The first ACT trial is testing the safety of hESC-derived retinal cells to treat patients with an eye disease called Stargardt's Macular Dystrophy (SMD).
The second ACT trial is testing the safety of hESC-derived retinal cells to treat patients with age-related macular degeneration.
In January, 2012, the investigators published a preliminary report on the first two patients treated with hESC-derived cells: www.ncbi.nlm.nih.gov/pubmed/22281388.

A third clinical trial using hESC-derived cells was halted on November 14, 2011. The trial was being conducted by a biotechnology called Geron, located in Menlo Park, California. Four patients with recent spinal cord injuries had been enrolled for its clinical trial of a hESC-derived therapy. The trial was testing the safety of using hESC-derived cells to achieve restoration of spinal cord function. Oligodendrocyte progenitor cells derived from hESCs were being injected directly into the lesion site of the patient's injured spinal cord. On November 14, Geron announced that it was discontinuing its stem cell programs to concentrate on cancer programs.

What about Other Types of Stem Cells?

Bone marrow contains blood-forming stem cells (hematopoietic stem cells) that have been used for decades to treat blood cancers and other blood disorders. Umbilical cord blood is another source of hematopoietic stem cells that is being used in treatment. You can see a list of diseases that may currently be treated with hematopoietic stem cells at the website of the National Marrow Donor Program.

Participating in Clinical Trials

Scientists are testing the abilities of many different types of stem cells to treat certain diseases. You can search for clinical trials using stem cells (or other methods) to treat a specific disease at ClinicalTrials.gov.]]> Stem Cell Methods Sat, 28 Apr 2012 07:39:25 +0000 http://e-biotek.com/forum/15-Stem-Cell-Methods/3225-Stem-Cells-and-Diseases.html#3225