Scientists discover DNA body clock

21/10/13
Scientists discover DNA body clock | Science | theguardian.com
Scientists discover DNA body clock
Newly discovered mechanism could help researchers understand
ageing process and lead to ways of slowing it down
Ian Sample, science correspondent
theguardian.com , Monday 2 1 October 2 01 3 01 .02 BST
Horv ath looked at the DNA of nearly 8,000 sam ples of 51 different healthy and cancerous cells and tissues.
Photograph: Zoonar Gm bH/Alam y
A US scientist has discovered an internal body clock based on DNA that measures the
biological age of our tissues and organs.
The clock shows that while many healthy tissues age at the same rate as the body as a
whole, some of them age much faster or slower. The age of diseased organs varied
hugely, with some many tens of years "older" than healthy tissue in the same person,
according to the clock.
Researchers say that unravelling the mechanisms behind the clock will help them
understand the ageing process and hopefully lead to drugs and other interventions that
slow it down.
Therapies that counteract natural ageing are attracting huge interest from scientists
because they target the single most important risk factor for scores of incurable diseases
that strike in old age.
www.theguardian.com/science/2013/oct/21/dna-body-clock-ageing/print
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Scientists discover DNA body clock | Science | theguardian.com
"Ultimately, it would be very exciting to develop therapy interventions to reset the clock
and hopefully keep us young," said Steve Horvath, professor of genetics and biostatistics
at the University of California in Los Angeles.
Horvath looked at the DNA of nearly 8,000 samples of 51 different healthy and
cancerous cells and tissues. Specifically, he looked at how methylation, a natural process
that chemically modifies DNA, varied with age.
Horvath found that the methylation of 353 DNA markers varied consistently with age
and could be used as a biological clock. The clock ticked fastest in the years up to around
age 20, then slowed down to a steadier rate. Whether the DNA changes cause ageing or
are caused by ageing is an unknown that scientists are now keen to work out.
"Does this relate to something that keeps track of age, or is a consequence of age? I
really don't know," Horvath told the Guardian. "The development of grey hair is a
marker of ageing, but nobody would say it causes ageing," he said.
The clock has already revealed some intriguing results. Tests on healthy heart tissue
showed that its biological age – how worn out it appears to be – was around nine years
younger than expected. Female breast tissue aged faster than the rest of the body, on
average appearing two years older.
Diseased tissues also aged at different rates, with cancers speeding up the clock by an
average of 36 years. Some brain cancer tissues taken from children had a biological age
of more than 80 years.
"Female breast tissue, even healthy tissue, seems to be older than other tissues of the
human body. That's interesting in the light that breast cancer is the most common
cancer in women. Also, age is one of the primary risk factors of cancer, so these types of
results could explain why cancer of the breast is so common," Horvath said.
Healthy tissue surrounding a breast tumour was on average 12 years older than the rest
of the woman's body, the scientist's tests revealed.
Writing in the journal Genome Biology, Horvath showed that the biological clock was
reset to zero when cells plucked from an adult were reprogrammed back to a stem-celllike state. The process for converting adult cells into stem cells, which can grow into any
tissue in the body, won the Nobel prize in 2012 for Sir John Gurdon at Cambridge
University and Shinya Yamanaka at Kyoto University.
"It provides a proof of concept that one can reset the clock," said Horvath. The scientist
now wants to run tests to see how neurodegenerative and infectious diseases affect, or
are affected by, the biological clock.
"These data could prove valuable in furthering our knowledge of the biological changes
www.theguardian.com/science/2013/oct/21/dna-body-clock-ageing/print
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Scientists discover DNA body clock | Science | theguardian.com
that are linked to the ageing process," said Veryan Codd, who works on the effects of
biological ageing in cardiovascular disease at Leicester University. "It will be important
to determine whether the accelerated ageing, as described here, is associated with other
age-related diseases and if it is a causal factor in, or a consequence of, disease
development.
"As more data becomes available, it will also be interesting to see whether a similar
approach could identify tissue-specific ageing signatures, which could also prove
important in disease mechanisms," she added.
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21/10/13
Endocrine Society, AACE release list of tests to avoid | Endocrinology
Endocrinology
Endocrine Society, AACE release list of tests to avoid
October 20, 2013
The Endocrine Society and the American Association of Clinical Endocrinologists have released a list of tests or procedures commonly
ordered but are not always necessary in clinical practice, according to a press release. The announcement was released as a result of
an initiative of the ABIM Foundation, known as the Choosing Wisely campaign.
“These recommendations give endocrinologists a platform to engage patients in important discussions about their health and the benefits
of various treatment options,” Teresa K. Woodruff, PhD, president of The Endocrine Society, said in a press release. “We are pleased
to be empowering patients and physicians to be true partners in determining the wisest course of care for each individual.”
The groups have listed five targeted, evidence-based recommendations that support conversation between patients and clinicians about
what type of care is needed, according to the press release:
1. Avoid routine multiple daily self-glucose monitoring in adults with stable type 2 diabetes on agents that do not cause hypoglycemia.
2. Do not routinely measure 1, 25-dihydroxyvitamin D unless the patient has hypercalcemia or decreased kidney function.
3. Do not routinely order a thyroid ultrasound in patients with abnormal thyroid function tests if there is no palpable abnormality of the
thyroid gland.
4. Do not order a total or free triiodothyronine level when assessing levothyroxine dose in hypothyroid patients.
5. Do not prescribe testosterone therapy unless there is biochemical evidence of testosterone deficiency.
“Each patient and encounter is unique, and there are many exceptions to each of the recommendations. Furthermore, the
recommendations are likely to evolve over time as more is learned,” Daniel Einhorn, MD, FACP, FACE, president of the American
College of Endocrinology, said in the press release.
For more information:
The Choosing Wisely Initiative of the ABIM Foundation. Accessed Oct. 16, 2013.
www.healio.com/endocrinology/practice-management/news/online/%7Bdd99083b-bddd-46b3-8377-ef218b1cf92a%7D/endocrine-society-aace-release-list-o…
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21/10/13
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Spanking tied to later aggression among kids
12:37am EDT
By Genevra Pittman
NEW YORK (Reuters Health) - Think spanking will help teach an out of control child to stay in line? A new study
suggests the opposite may be true.
Researchers found kids who were spanked as five-year-olds were slightly more likely to be aggressive and break rules
later in elementary school.
Those results are in keeping with past research, said Elizabeth Gershoff. She studies parental discipline and its effects
at the University of Texas at Austin.
"There's just no evidence that spanking is good for kids," she told Reuters Health.
"Spanking models aggression as a way of solving problems, that you can hit people and get what you want," Gershoff,
who wasn't involved in the new study, said.
"When (children) want another kid's toy, the parents haven't taught them how to use their words or how to negotiate."
Despite mounting evidence on the harms tied to spanking, it is "still a very typical experience" for U.S. children, the
study's lead author said.
"Most kids experience spanking at least some point in time," Michael MacKenzie, from Columbia University in New York,
said. "So there's this disconnect."
His team used data from a long-term study of children born in one of 20 U.S. cities between 1998 and 2000. The new
report includes about 1,900 kids.
Researchers surveyed parents when children were three and five years old about whether and how often they spanked
their child.
Then they asked mothers about their kid's behavior problems and gave the children a vocabulary test at age nine.
A total of 57 percent of mothers and 40 percent of fathers said they spanked children when they were three years old.
That fell slightly to 52 percent of mothers and 33 percent of fathers who spanked at age five.
Children acted out more and were more aggressive when they had been spanked by their mothers as five-year-olds,
whether regularly or occasionally.
Spanking by mothers at least twice a week was tied to a two-point increase on a 70-point scale of problem behavior.
That was after the researchers took into account children's behavior at younger ages and other family characteristics.
There was no link between spanking by parents at age three and children's later behavior, however.
Kids also tended to score lower on vocabulary tests when they had been regularly spanked by their fathers at age five,
MacKenzie and his colleagues write in Pediatrics.
The average vocabulary score for all nine-year-olds in the study was 93, slightly below the test-wide standard score of
100. Frequent spanking by fathers was linked to a four-point lower score. But the researchers couldn't be sure that
small difference wasn't due to chance.
Gershoff said the finding is a bit hard to interpret. "I don't think that spanking makes kids stupider," she said.
It's possible that parents who are spanking are not talking to their children as often, Gershoff said. Or kids who are
spanked and act out could be more distracted in the classroom.
When it comes to disciplining children, she said there's more evidence on what doesn't work long-term than what does.
"We know that spanking doesn't work, we know that yelling doesn't work," Gershoff said. "Timeout is kind of a mixed
bag. We know that reasoning does work."
MacKenzie said spanking continues to seem effective to parents in the short term, which makes it hard to change their
minds about it.
"It's strongly associated with immediate compliance," he told Reuters Health. "Children will change their behavior in the
moment."
Because family strain and spanking often go together, he said doctors should try to support stressed parents to
encourage more positive forms of discipline.
"The techniques that are designed to promote positive behaviors … oftentimes take more effort and time to put into
place," MacKenzie said.
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JN - Imprimir
Osteoporose afeta 500 mil portugueses
A Sociedade Portuguesa de Osteoporose e Doenças
Ósseas Metabólicas assinala, domingo, o Dia Mundial
da Osteoporose com um conjunto de iniciativas
destinadas a sensibilizar a população para esta
doença que afeta cerca de 500 mil portugueses.
"A osteoporose é muito frequente, estima-se que
depois dos 50 anos uma em cada três mulheres ou um
em cada cinco homens vão ter uma fratura provocada
por osteoporose até ao fim da vida", disse à Lusa Ana
Paula Barbosa, da Sociedade Portuguesa de
Osteoporose e Doenças Ósseas Metabólicas
(SPODOM).
Segundo a especialista, "a nível mundial considera-se
a osteoporose como estando ao nível das doenças
cardiovasculares e do próprio cancro. É mais provável
aparecer esta doença do que muitas vezes aparecer o
cancro da mama na mulher ou da próstata no homem".
Patrocínio
Uma das principais consequências desta doença é a fratura, principalmente a da anca, que afeta
homens e mulheres com mais de 50 anos.
Segundo dados da SPODOM, atualmente estima-se que ocorra uma fratura a cada três segundos, em
algum lugar do planeta. As estatísticas dão conta que, em casos mais graves, 20% dos doentes que
sofrem uma fratura no colo do fémur morrem no período de seis meses após o incidente, 40% perdem
autonomia na sua mobilidade e 33% acabam por recorrer a lares ou outro tipo de dependência de
terceiros.
Esta "doença silenciosa" afeta homens e mulheres, embora apresente maior incidência no sexo
feminino, especialmente após a menopausa.
Caracterizada pela diminuição da densidade óssea e deterioração estrutural do tecido ósseo, a doença
conduz a uma maior fragilidade óssea e a um aumento da suscetibilidade a fraturas, especialmente na
anca, coluna e pulso.
As ações de sensibilização a realizar no âmbito do Dia Mundial da Osteoporose vão decorrer ao longo
da semana de 20 de outubro em hospitais, centros de saúde e locais públicos, como estações de
metro e de comboio em Lisboa, Porto e Coimbra.
A SPODOM pretende não só dar a conhecer esta patologia, mas também divulgar, junto da população,
algumas medidas de prevenção para a doença: incentivar uma alimentação rica em cálcio e encorajar a
prática regular de exercício físico.
publicado a 2013-10-18 às 14:54
Para mais detalhes consulte:
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