Tuesday, December 4, 2018
Sunday, December 2, 2018
Wednesday, November 28, 2018
Scientists regrow hair
Scientists regrow hair on wounded skin
The findings by researchers at the New York University (NYU) School of Medicine in the US better explain why hair does not normally grow on wounded skin.
Researchers have regrown hair strands on damaged skin by stirring crosstalk among skin cells that form the roots of hair.
The
findings by researchers at the New York University (NYU) School of
Medicine in the US better explain why hair does not normally grow on
wounded skin.The study, published in the journal Nature Communications, may help in the search for better drugs to restore hair growth.
It examined the effect of distinct signalling pathways in damaged skin of laboratory mice.
Experiments focused on cells called fibroblasts that secrete collagen, the structural protein most responsible for maintaining the shape and strength of skin and hair.
Researchers activated the sonic hedgehog signalling pathway used by cells to communicate with each other.
The pathway is known to be very active during the early stages of human growth in the womb, when hair follicles are formed, but is otherwise stalled in wounded skin in healthy adults.
Researchers said this possibly explains why hair follicles fail to grow in skin replaced after injury or surgery.
Regrowing hair on damaged skin is an unmet need in medicine, Ito said, because of the disfigurement suffered by thousands from trauma, burns, and other injuries.
However, her more immediate goal, she said, is to signal mature skin to revert back to its embryonic state so that it can grow new hair follicles, not just on wounded skin, but also on people who have gone bald from ageing.
Ito said scientists have until now assumed that, as part of the healing process, scarring and collagen buildup in damaged skin were behind its inability to regrow hair.
"Now we know that it's a signalling issue in cells that are very active as we develop in the womb, but less so in mature skin cells as we age," she said.
Key among the study's findings was that no signs of hair growth were observed in untreated skin, but were observed in treated skin, offering evidence that sonic hedgehog signalling was behind the hair growth, researchers said.
To bypass the risk of tumours reported in other experiments that turned on the sonic hedgehog pathway, the team turned on only fibroblasts located just beneath the skin's surface where hair follicle roots (dermal papillae) first appear.
Researchers also zeroed in on fibroblasts because the cells are known to help direct some of the biological processes involved in healing.
Hair regrowth was observed within four weeks after skin wounding in all treated mice, with hair root and shaft structures starting to appear after nine weeks.
Hedgehog Signaling Interactive Pathway
Pathway Description:
The
evolutionarily conserved Hedgehog (Hh) pathway is essential for normal
embryonic development and plays critical roles in adult tissue
maintenance, renewal and regeneration. Secreted Hh proteins act in a
concentration- and time-dependent manner to initiate a series of
cellular responses that range from survival and proliferation to cell
fate specification and differentiation.
Proper
levels of Hh signaling require the regulated production, processing,
secretion and trafficking of Hh ligands– in mammals this includes Sonic
(Shh), Indian (Ihh) and Desert (Dhh). All Hh ligands are synthesized as
precursor proteins that undergo autocatalytic cleavage and concomitant
cholesterol modification at the carboxy terminus and palmitoylation at
the amino terminus, resulting in a secreted, dually-lipidated protein.
Hh ligands are released from the cell surface through the combined
actions of Dispatched and Scube2, and subsequently trafficked over
multiple cells through interactions with the cell surface proteins LRP2
and the Glypican family of heparan sulfate proteoglycans (GPC1-6).
Hh
proteins initiate signaling through binding to the canonical receptor
Patched (PTCH1) and to the co-receptors GAS1, CDON and BOC. Hh binding
to PTCH1 results in derepression of the GPCR-like protein Smoothened
(SMO) that results in SMO accumulation in cilia and phosphorylation of
its cytoplasmic tail. SMO mediates downstream signal transduction that
includes dissociation of GLI proteins (the transcriptional effectors of
the Hh pathway) from kinesin-family protein, Kif7, and the key
intracellular Hh pathway regulator SUFU.
GLI
proteins also traffic through cilia and in the absence of Hh signaling
are sequestered by SUFU and Kif7, allowing for GLI phosphorylation by
PKA, GSK3β and CK1, and subsequent processing into transcriptional
repressors (through cleavage of the carboxy-terminus) or targeting for
degradation (mediated by the E3 ubiquitin ligase β-TrCP). In response to
activation of Hh signaling, GLI proteins are differentially
phopshorylated and processed into transcriptional activators that induce
expression of Hh target genes, many of which are components of the
pathway (e.g. PTCH1 and GLI1). Feedback mechanisms include the induction
of Hh pathway antagonists (PTCH1, PTCH2 and Hhip1) that interfere with
Hh ligand function, and GLI protein degradation mediated by the E3
ubiquitin ligase adaptor protein, SPOP.
In addition
to vital roles during normal embryonic development and adult tissue
homeostasis, aberrant Hh signaling is responsible for the initiation of a
growing number of cancers including, classically, basal cell carcinoma,
edulloblastoma, and rhabdomyosarcoma; more recently overactive Hh
signaling has been implicated in pancreatic, lung, prostate, ovarian,
and breast cancer. Thus, understanding the mechanisms that control Hh
pathway activity will inform the development of novel therapeutics to
treat a growing number of Hh-driven pathologies.
Tuesday, November 27, 2018
Herpes Test: What You Should Know
Herpes Test: What You Should Know
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You get genital herpes by having sex -- vaginal, oral, or anal -- with someone who already has it.
Thinking you have genital herpes naturally can bring up strong emotions. Talk to your doctor about getting tested. It could help you to learn more about the disease and talk honestly with your sexual partner. You might want to join a support group, too.
Do I Need to Get Tested?
Many people with herpes don’t have any symptoms. If symptoms do show up, you might first feel tingling or burning near your genitals.You might then get blisters around your genitals, anus, thighs, or buttocks. When the blisters break, they leave sores that can take a few weeks to heal. They usually won’t leave any scars.
To check for herpes, your doctor usually does a physical exam and then likely orders one of these tests:
- Viral culture
- Polymerase chain reaction (PCR) test
- Blood test
A “negative” viral culture or PCR result could mean you don’t have genital herpes. But in some cases, a person could still have genital herpes and a negative result. That's likely due to other factors related to how much virus there is in the sores.
You don’t need to do anything to prepare for these tests. They don’t take long, but how soon you get your results depends on the type of test and the lab that does it.
Viral Culture
For this test, your doctor scrapes or swabs one of your sores to take a sample. A lab then checks the sample for the herpes virus. It can take up to 7 days to get your results.This test is best used within 48 hours of when you first see symptoms. After that time, the level of herpes virus starts to drop. That means there’s a higher chance the test could say you don’t have herpes when you really do.
Polymerase Chain Reaction (PCR) Test
As with the viral culture, your doctor swabs or scrapes a sample from one of your sores. A lab gets the sample and looks for genes from the herpes virus. PCR test results usually come back to you within 24 hours.You’re more likely to get this test if you have symptoms but it’s been longer than 48 hours since they showed up. In this case, you can rely on the results from this test more than the viral culture.
Blood Test
A small amount of blood is sent to a lab that then checks it for herpes “antibodies.” Those are something your body makes to fight the virus.
Continue Reading Below
You might get a blood test if you think you have been exposed but you don’t have any symptoms.Labs may use different types of blood tests. With some you can get results the same day, but others may take up to 3 weeks.
Next Steps
There’s no cure for genital herpes, but it can be treated.If you do have it, your doctor can help you manage it. There are drugs that can shorten or prevent outbreaks, ease symptoms, and lower the chances your sex partners will get it.
Sunday, November 25, 2018
First Gene-Edited Babies Claimed in China
2 hours ago - A Chinese researcher claims that he helped make the world's first genetically edited babies — twin girls whose DNA he said he altered with a ...
HONG
KONG — A Chinese researcher claims that he helped make the world's
first genetically edited babies — twin girls born this month whose DNA
he said he altered with a powerful new tool capable of rewriting the
very blueprint of life.
If true, it would be a profound leap of science and ethics.
A
U.S. scientist said he took part in the work in China, but this kind of
gene editing is banned in the United States because the DNA changes can
pass to future generations and it risks harming other genes.
Many mainstream scientists think it's too unsafe to try, and some denounced the Chinese report as human experimentation.
The
researcher, He Jiankui of Shenzhen, said he altered embryos for seven
couples during fertility treatments, with one pregnancy resulting thus
far. He said his goal was not to cure or prevent an inherited disease,
but to try to bestow a trait that few people naturally have — an ability
to resist possible future infection with HIV, the AIDS virus.
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He
said the parents involved declined to be identified or interviewed, and
he would not say where they live or where the work was done.
There
is no independent confirmation of He's claim, and it has not been
published in a journal, where it would be vetted by other experts. He
revealed it Monday in Hong Kong to one of the organizers of an
international conference on gene editing that is set to begin Tuesday,
and earlier in exclusive interviews with The Associated Press.
"I
feel a strong responsibility that it's not just to make a first, but
also make it an example," He told the AP. "Society will decide what to
do next" in terms of allowing or forbidding such science.
Some scientists were astounded to hear of the claim and strongly condemned it.
It's
"unconscionable ... an experiment on human beings that is not morally
or ethically defensible," said Dr. Kiran Musunuru, a University of
Pennsylvania gene editing expert and editor of a genetics journal.
"This
is far too premature," said Dr. Eric Topol, who heads the Scripps
Research Translational Institute in California. "We're dealing with the
operating instructions of a human being. It's a big deal."
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However,
one famed geneticist, Harvard University's George Church, defended
attempting gene editing for HIV, which he called "a major and growing
public health threat."
"I think this is justifiable," Church said of that goal.
In
recent years scientists have discovered a relatively easy way to edit
genes, the strands of DNA that govern the body. The tool, called
CRISPR-cas9, makes it possible to operate on DNA to supply a needed gene
or disable one that's causing problems.
It's
only recently been tried in adults to treat deadly diseases, and the
changes are confined to that person. Editing sperm, eggs or embryos is
different — the changes can be inherited. In the U.S., it's not allowed
except for lab research. China outlaws human cloning but not
specifically gene editing.
He Jiankui
(HEH JEE'-an-qway), who goes by "JK," studied at Rice and Stanford
universities in the U.S. before returning to his homeland to open a lab
at Southern University of Science and Technology of China in Shenzhen,
where he also has two genetics companies.
The
U.S. scientist who worked with him on this project after He returned to
China was physics and bioengineering professor Michael Deem, who was
his adviser at Rice in Houston. Deem also holds what he called "a small
stake" in — and is on the scientific advisory boards of — He's two
companies.
The Chinese researcher
said he practiced editing mice, monkey and human embryos in the lab for
several years and has applied for patents on his methods.
He
said he chose embryo gene editing for HIV because these infections are a
big problem in China. He sought to disable a gene called CCR5 that
forms a protein doorway that allows HIV, the virus that causes AIDS, to
enter a cell.
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All
of the men in the project had HIV and all of the women did not, but the
gene editing was not aimed at preventing the small risk of
transmission, He said. The fathers had their infections deeply
suppressed by standard HIV medicines and there are simple ways to keep
them from infecting offspring that do not involve altering genes.
Instead, the appeal was to offer couples affected by HIV a chance to have a child that might be protected from a similar fate.
He
recruited couples through a Beijing-based AIDS advocacy group called
Baihualin. Its leader, known by the pseudonym "Bai Hua," told the AP
that it's not uncommon for people with HIV to lose jobs or have trouble
getting medical care if their infections are revealed.
Here is how He described the work:
The
gene editing occurred during IVF, or lab dish fertilization. First,
sperm was "washed" to separate it from semen, the fluid where HIV can
lurk. A single sperm was placed into a single egg to create an embryo.
Then the gene editing tool was added.
When
the embryos were 3 to 5 days old, a few cells were removed and checked
for editing. Couples could choose whether to use edited or unedited
embryos for pregnancy attempts. In all, 16 of 22 embryos were edited,
and 11 embryos were used in six implant attempts before the twin
pregnancy was achieved, He said.
Tests
suggest that one twin had both copies of the intended gene altered and
the other twin had just one altered, with no evidence of harm to other
genes, He said. People with one copy of the gene can still get HIV,
although some very limited research suggests their health might decline
more slowly once they do.
Several
scientists reviewed materials that He provided to the AP and said tests
so far are insufficient to say the editing worked or to rule out harm.
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They
also noted evidence that the editing was incomplete and that at least
one twin appears to be a patchwork of cells with various changes.
"It's
almost like not editing at all" if only some of certain cells were
altered, because HIV infection can still occur, Church said.
Church
and Musunuru questioned the decision to allow one of the embryos to be
used in a pregnancy attempt, because the Chinese researchers said they
knew in advance that both copies of the intended gene had not been
altered.
"In that child, there really
was almost nothing to be gained in terms of protection against HIV and
yet you're exposing that child to all the unknown safety risks,"
Musunuru said.
The use of that embryo
suggests that the researchers' "main emphasis was on testing editing
rather than avoiding this disease," Church said.
Even
if editing worked perfectly, people without normal CCR5 genes face
higher risks of getting certain other viruses, such as West Nile, and of
dying from the flu. Since there are many ways to prevent HIV infection
and it's very treatable if it occurs, those other medical risks are a
concern, Musunuru said.
There also
are questions about the way He said he proceeded. He gave official
notice of his work long after he said he started it — on Nov. 8, on a
Chinese registry of clinical trials.
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It's
unclear whether participants fully understood the purpose and potential
risks and benefits. For example, consent forms called the project an
"AIDS vaccine development" program.
The
Rice scientist, Deem, said he was present in China when potential
participants gave their consent and that he "absolutely" thinks they
were able to understand the risks.
Deem said he worked with He on vaccine research at Rice and considers the gene editing similar to a vaccine.
"That might be a layman's way of describing it," he said.
Both men are physics experts with no experience running human clinical trials.
The
Chinese scientist, He, said he personally made the goals clear and told
participants that embryo gene editing has never been tried before and
carries risks. He said he also would provide insurance coverage for any
children conceived through the project and plans medical follow-up until
the children are 18 and longer if they agree once they're adults.
Further
pregnancy attempts are on hold until the safety of this one is analyzed
and experts in the field weigh in, but participants were not told in
advance that they might not have a chance to try what they signed up for
once a "first" was achieved, He acknowledged. Free fertility treatment
was part of the deal they were offered.
He
sought and received approval for his project from Shenzhen Harmonicare
Women's and Children's Hospital, which is not one of the four hospitals
that He said provided embryos for his research or the pregnancy
attempts.
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Some
staff at some of the other hospitals were kept in the dark about the
nature of the research, which He and Deem said was done to keep some
participants' HIV infection from being disclosed.
"We think this is ethical," said Lin Zhitong, a Harmonicare administrator who heads the ethics panel.
Any
medical staff who handled samples that might contain HIV were aware, He
said. An embryologist in He's lab, Qin Jinzhou, confirmed to the AP
that he did sperm washing and injected the gene editing tool in some of
the pregnancy attempts.
The study
participants are not ethicists, He said, but "are as much authorities on
what is correct and what is wrong because it's their life on the line."
"I
believe this is going to help the families and their children," He
said. If it causes unwanted side effects or harm, "I would feel the same
pain as they do and it's going to be my own responsibility."
___
AP
Science Writer Christina Larson, AP videographer Emily Wang and AP
translator Fu Ting contributed to this report from Beijing and Shenzhen,
China.
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