Stories tagged Cells

Feb
05
2008

Hetero, homo, and 3-way embryo creation

Embryo - 5 weeks
Embryo - 5 weeksCourtesy Ed Uthman
Lesbian couples could one day have children who share both their genes. Karim Nayernia, Professor of Stem Cell Biology at Newcastle University, has applied for ethical approval from the university to use bone marrow stem cells from women to start experiments to derive female sperm.

“I think, in principle, it will be scientifically possible,” Prof Nayernia told New Scientist.

Babies from two men

Other research is setting the stage for a gay man to donate skin cells that could be used to make eggs, which could then be fertilized by his partner’s sperm. A surrogate's uterus would be needed to bring the baby to term.

In Brazil, a team led by Dr Irina Kerkis of the Butantan Institute in Saõ Paulo claims to have made both sperm and eggs from cultures of male mouse embryonic stem cells in the journal Cloning and Stem Cells.

Babies from a man and two women

A whole class of hereditary diseases, including some forms of epilepsy, result from faulty DNA related to mitochondria. Starting with 10 severely abnormal embryos left over from traditional fertility treatment, researchers removed the nucleus, containing DNA from the mother and father, from the embryo, and implanted it into a donor egg whose DNA had been largely removed. The only genetic information remaining from the donor egg was the tiny bit that controls production of mitochondria. The embryos then began to develop normally, but were destroyed within six days.

"We believe that from this work, and work we have done on other animals that in principle we could develop this technique and offer treatment in the forseeable future that will give families some hope of avoiding passing these diseases to their children." said Patrick Chinnery, a member of the Newcastle team.

If you have an opinion on these types of research, feel free to comment.

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Jan
29
2008

Often you read about people afraid or worried about vaccines but a recent article published in the Journal of the American Medical Association reports that vaccines have decreased hospitalizations and deaths related to the most vaccine-preventable diseases. And occurrences of these diseases are at an all time low. The researchers compared illness and death before and after widespread implementation of national vaccine recommendations for 13 different vaccine-preventable diseases. These include: diphtheria, invasive Haemophilus influenzae type b, hepatitis A, acute hepatitis B, measles, mumps, pertussis, poliomyelitis, rubella, Streptococcus pneumoniae, smallpox, tetanus and varicella. The data showed large reductions in the number of cases after vaccinations were recommended for each of the diseases. For an interesting view of a vaccine life cycle go to this web site

Vaccines changed medicine
(From the Vaccine Education Center)
Official Rubella Fighter: The “rubella umbrella” campaign urged parents to have their children immunized from this viral infection. Rubella, or more commonly referred to as the German measles, is a mild childhood illness that can pose a serious threat to a fetus, if the mother contracts the illness during pregnancy. More than 20,000 babies were born with congenital rubella syndrome (CRS) during an outbreak of rubella in 1964-65. This epidemic cost the country an estimated $1.5 billion. The rubella vaccine was first licensed in the U.S. in 1969.
Official Rubella Fighter: The “rubella umbrella” campaign urged parents to have their children immunized from this viral infection. Rubella, or more commonly referred to as the German measles, is a mild childhood illness that can pose a serious threat to a fetus, if the mother contracts the illness during pregnancy. More than 20,000 babies were born with congenital rubella syndrome (CRS) during an outbreak of rubella in 1964-65. This epidemic cost the country an estimated $1.5 billion. The rubella vaccine was first licensed in the U.S. in 1969.Courtesy CDC

Vaccines have literally transformed the landscape of medicine over the course of the 20th century.

Before vaccines, parents in the United States could expect that every year:
• Polio would paralyze 10,000 children.
• Rubella (German measles) would cause birth defects and mental retardation in as many as 20,000 newborns.
• Measles would infect about 4 million children, killing 3,000.
• Diphtheria would be one of the most common causes of death in school-aged children.
• A bacterium called Haemophilus influenzae type b (Hib) would cause meningitis in 15,000 children, leaving many with permanent brain damage.
• Pertussis (whooping cough) would kill thousands of infants.
Vaccines have reduced and, in some cases, eliminated many diseases that killed or severely disabled people just a few generations before. For most Americans today, vaccines are a routine part of healthcare.

However, the disappearance of many childhood diseases has led some parents to question whether vaccines are still necessary. Further, a growing number of parents are concerned that vaccines may actually be the cause of diseases such as autism, hyperactivity, developmental delay, attention deficit disorder, diabetes, multiple sclerosis, and sudden infant death syndrome (SIDS) among others. These concerns have caused some parents to delay vaccines or withhold them altogether from their children.
For information on vaccine safety go to this page on the CDC website or this page on the Vaccine Education Center website.

How vaccines work
(from the CDC)

Children are born with a full immune system composed of cells, glands, organs, and fluids that are located throughout his or her body to fight invading bacteria and viruses. The immune system recognizes germs that enter the body as "foreign" invaders, or antigens, and produces protein substances called antibodies to fight them. A normal, healthy immune system has the ability to produce millions of these antibodies to defend against thousands of attacks every day, doing it so naturally that people are not even aware they are being attacked and defended so often (Whitney, 1990). Many antibodies disappear once they have destroyed the invading antigens, but the cells involved in antibody production remain and become "memory cells." Memory cells remember the original antigen and then defend against it when the antigen attempts to re-infect a person, even after many decades. This protection is called immunity.
Vaccines contain the same antigens or parts of antigens that cause diseases, but the antigens in vaccines are either killed or greatly weakened. When they are injected into fatty tissue or muscle, vaccine antigens are not strong enough to produce the symptoms and signs of the disease but are strong enough for the immune system to produce antibodies against them (Tortora and Anagnostakos, 1981). The memory cells that remain prevent re-infection when they encounter that disease in the future. Thus, through vaccination, children develop immunity without suffering from the actual diseases that vaccines prevent. But remember…what's in the vaccine is just strong enough to promote the body's response to make antibodies, but much weaker than the viruses or bacteria in their natural, or "wild," states. For another description see this webpage

Jan
26
2008

Template for life created out of lab chemicals

Mycoplasma genitalium
Mycoplasma genitaliumCourtesy Department of Energy
Starting with simple laboratory chemicals, a group of scientists led by Craig Venter have replicated an entire bacterial genome. Based on an existing organism, the molecule of DNA Mycoplasma genitalium, composed of 582,970 base pairs, could come "alive" and start to replicate itself when inserted into a "hollow" bacterial host from which the DNA has been removed. The procedure titled, Complete Chemical Synthesis, Assembly, and Cloning of a Mycoplasma genitalium Genome was just published in Science.

"Venter and his colleagues have already managed to transplant the DNA from one bacteria into another, making it change species (see Genome transplant makes species switch/news070625-9). These bacteria were closely related to M. genitalium. If the transplant can be repeated with a man-made genome adapted from M. genitalium, the result could qualify as the first artificial life form (see 'What is artificial life?')" Nature News.

Customizing bacteria to solve problems

The genome of M. genitalium is one of the simplest, consisting of only 470 coding regions. Venter suspects about 100 of these are not necessary. The next step is to strip out various segments in an attempt to build the minimal amount of code that is essential for "life". This minimal component could then serve as a chassis to which "designer" genes could be attached, genes that could turn the bacteria into biological factories for making hydrogen (or other fuels).

Recommended reading:
Longest Piece of Synthetic DNA Yet (Scientific American)

Jan
22
2008

Human embryos using animal eggs

Embryo, 8 cells
Embryo, 8 cellsCourtesy Ekem
Last week we learned that scientists cloned human embryos using adult skin and fertile eggs from a woman donor. Now the Human Fertilization and Embryology Authority in Britain has approved creating human embryos using eggs from animals like cows or rabbits. Because the animal cell's nucleus would be removed before human DNA was added, scientists said the resulting egg would not be a chimera.

"Cow eggs seem to be every bit as good at doing this job as human eggs," said Lyle Armstrong of Newcastle University.
"We will only use them as a scientific tool and we need not worry about cells being derived from them ever being used to treat human diseases," Armstrong said.

Technique eliminates destruction of human eggs

Animal eggs are abundant and easily obtained. Researchers hope to refine their techniques by practicing first on animal eggs to producing human stem cells. Human stem cells, which have the ability to develop into any cell in the human body, show promise for understanding and healing many human ailments. The embryos would not be allowed to develop for more than two weeks.

Jan
22
2008

Decellularization: A rat heart as the cells are removed (left three images) and replaced (right two images) over time.
Decellularization: A rat heart as the cells are removed (left three images) and replaced (right two images) over time.Courtesy Thomas Matthiesen, University of Minnesota

Science fiction?
Did you know that nearly 5 million people live with heart failure? More surprisingly, approximately 50,000 United States patients die annually waiting for a donor heart.

University of Minnesota researchers recently announced they have created a beating heart in the laboratory. It sounds like science fiction, but it is a real medical breakthrough. The researchers removed the tissue from a dead rat heart and replaced it with living cells from newborn rats. With the help of electrical signals, the entire heart began to beat.

"Ghost hearts"
The researchers used a detergent to remove the cells from the rat hearts. This left behind only the nonliving fibers that give the heart its shape. The result was a white, rubbery, 3-D “skeleton”. This structure, called the extracellular matrix, allows cells to attach and grow into tissue, and gives the heart muscle something to pull against. The researchers injected cells from newborn rats into the left ventricle and pumped oxygen and nutrients through the structure of blood vessels. They helped the process by sending electrical signals through the new tissue. In eight days, the hearts were pumping – some continued beating for 40 days.

The supply of donor organs is limited and the risks for infection or rejection of the transplanted organ can be high. If the technique is perfected, doctors may be able to use patients’ own stem cells to recellularize a donor heart.

The next steps
The University of Minnesota research team has successfully decellularized pig hearts, and hopes that other types of organs can be created in the future.

Jan
18
2008

Blastocyst day 5
Blastocyst day 5Courtesy Ekem

DNA from clone identical to that from adult skin donor

A paper published in the online journal, Stem Cells, yesterday titled "Development of Human cloned Blastocysts Following Somatic Cell Nuclear Transfer (SCNT) with Adult Fibroblasts" is the first documented demonstration that ordinary cells from an adult human can be used to make cloned embryos mature enough to produce stem cells

"A research team at Stemagen, a biotech company based in San Diego, California, started with skin cells donated by two men and 25 eggs, or oocytes, donated by women at a nearby fertility center. The scientists removed the DNA-containing nuclei from the eggs and replaced them with DNA from the donor skin cells. Two of the eggs became 5-day-old embryos, or blastocysts, that were clones of the male donors."Science

Why are we cloning humans?

The next big step will be to create a human embryonic stem cell line from cloned embryos. Stem cells from cloned embryos could provide a valuable tool for studying diseases, screening drugs, and creating transplant material to treat conditions like diabetes and Parkinson's disease.

Should we be doing this?

As expected, critics are raising objections. This procedure requires cutting healthy eggs out of women, then altering them to produce living embryos, which are then destroyed. Should this be allowed?

Read more

Jan
14
2008

Dead heart transformed into a living heart

Tissue engineering has allowed a dead rat heart to be stripped of its cellular material, then after injecting the remaining scaffold material with with new cardiac cells, the cells organized themselves until the heart became alive.

A "crazy idea" at the University of Minnesota that could not get federal funding yielded "unbelievable" results after getting funding from the University of Minnesota and from the Medtronic Research Foundation.

New source for replacement organs

The accomplishment gave a significant boost to medicine’s dream of growing human organs to replace damaged ones. Organ transplants usually require replacement organs that fulfill extreme compatibility issues. By using the patients own cells in the rebuilt organs scientists hope to eliminate the need for patients to take anti-rejection drugs for the rest of their lives.

Growing human hearts at least 10 years away, if ever

The next step will be to use these techniques on pig hearts. Pig hearts are similar enough to a humans that parts from them have already been used in humans.

"Although this is only a first step requiring considerable follow-up development, the study nevertheless represents an exciting breakthrough that will eventually make the prospect of repairing damaged hearts a reality and will also be an approach that can be extended to other organs." Dr Jon Frampton Wellcome Trust Senior Fellow at the University of Birmingham

Source articles
TwinCities.com
New York Times
BBC News
USA Today
Nature Medicine journal's Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart (abstract)

Jan
11
2008

The twin on the left contemplates her brother
The twin on the left contemplates her brotherCourtesy Pat Ryan
In Great Britain it's been discovered that twins, who had been separated at birth and raised in different families somehow met in later life and married each other without knowing they were brother and sister.

The bizarre story has raised concerns of the importance of adopted children being able to find out information about their biological families.

The identity of the two people involved is being kept secret, and since the discovery their marriage has been annulled. But efforts are underway to insure that something similar doesn't happen again.

Each sibling said they felt a strong attraction to the other, something that has been seen in other separated sibling cases.

"We have a resistance, a very strong incest taboo where we are aware that someone is a biological relative," said Pam Hodgkins, of the charity Adults Affected by Adoption. "But when we are unaware of that relationship, we are naturally drawn to people who are quite similar to ourselves. And of course there is unlikely to be anyone more similar to any individual than their sibling."

STORY SOURCE
BBC.com

Jan
10
2008

Glowing green pigs: Just in time for St. Patrick's Day.
Glowing green pigs: Just in time for St. Patrick's Day.Courtesy johnmuk
A few years back scientists in Taiwan announced that they had genetically altered three cloned pigs so that they glowed fluorescent green. The feat was accomplished by injecting porcine embryos with fluorescent green protein from jellyfish.

Pigs are often used in studying human diseases.

In the Taiwanese experiment, the altered pigs’ internal organs glowed green throughout under ultraviolet light. On the outside they emitted a light green tint, particularly around their knuckles, eyes, and snout.

This week Chinese scientists announced that one of the altered pigs has successfully passed on its glow genes to some of its progeny. Two of 11 piglets born are displaying the same glowing traits their genetically engineered mother had been given in the lab. What this proves is that the sow remained fertile despite the engineering, and was able to pass on the altered gene.

The researchers hope the process will be useful in stem cell research and the monitoring of healing tissue during human transplants and other such procedures.

At last report, the mother pig was doing fine and glowing with pride.

Jan
09
2008

Psittacosaurus: Look how his skin bristles and shines!
Psittacosaurus: Look how his skin bristles and shines!Courtesy AMNH
No, this isn't about making your skin brontosaurus smooth or how to remove the million year-old age spots you've noticed cropping up on the back of your hands. This is about the secrets revealed in the remains of a 100 million year-old plant-eating dinosaur that are providing new information about the anatomy of the prehistoric beasts.

The Psittacosaurus (“parrot lizard”) fossil was dug up in China by paleontologists from England and South Africa. Besides the usual bones, some of the beaked dinosaur’s skin was preserved as well, providing a rare glimpse into its skin structure.

The outer covering of the bipedal herbivore seems to have been torn open by a predator or scavenger, leaving its skin folded back to reveal a cross-section of it. Tooth marks found on the fossil add weight to that theory.

The preservation of skin and other soft tissue is a rare occurrence in the fossil record. But sometimes, unusual burial conditions can result in some uncommon and very remarkable fossils.

In the Psittacosaur’s case, the folded back skin exhibits more than 25 layers of collagen, suggesting it to be of a rugged variety like that of sharks or reptiles today. A tough hide would have been an asset against the daily rigors the Psittacosaurus no doubt faced during its lifetime in the Early Cretaceous.

The scientists also wonder if the thick skin may not have been further protected with feather or scales. Of course, all you need is a bottle of Skin-so-soft or some Vaseline.

LINKS
Story on BBC.com