Creative campaigns are needed to reach some groups of young women, researchers say.
No-show women at cervical screening ‘unaware of test’
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Daily Archives: 29/06/2017
‘Ban parents from leaving engines on’, says guidance
Doctors want an end to leaving the car running at the school gates.
Ancient South Carolina whale yields secrets to filter feeding’s origins
The blue whale is the largest animal that has ever lived. And yet they feed almost exclusively on tiny crustaceans known as krill. The secret is in the baleen, a complex filter-feeding system that allows the enormous whales to strain huge volumes of saltwater, leaving only krill and other small organisms behind. Now, researchers who have described an extinct relative of baleen whales in Current Biology on June 29 offer new insight into how baleen first evolved.
The findings shed light on a long-standing debate about whether the first baleen whales were toothless suction feeders or toothed whales that used their teeth like a sieve to filter prey out of water, the researchers say. The teeth of the newly discovered species of mysticete, called Coronodon havensteini, lend support to the latter view.
“We know from the fossil record that the ancestors of baleen whales had teeth,” says Jonathan Geisler of the New York Institute of Technology College of Osteopathic Medicine. “However, the transition from teeth to baleen is controversial. Our study indicates that early toothed whales used spaces between their large complex teeth for filtering and that baleen gradually replaced teeth over millions of years.”
The new whale species was found in the early 2000s by a scuba diver in South Carolina’s Wando River. He was looking for shark teeth and found the fossilized whale instead. The whale, which lived some 30 million years ago, was later recognized as a representative of a new transitional species.
“The skull of this species indicates that it split off very early in mysticete whale evolution, and our analyses confirm that evolutionary position,” Geisler says.
Geisler and his colleagues realized that meant the whale could offer important clues about the teeth to baleen transition. The whale under study also had other interesting features. It was larger than other toothed mysticetes, with a skull nearly one meter long. Its large molars in comparison to other whales further suggested an unusual feeding behavior.
Closer examination of the shape and wear on the whale’s teeth led the researchers to conclude that the whale used its front teeth to snag prey. But the whale’s large, back molars were used in filter feeding, by expelling water through open slots between the closed teeth.
“The wear on the molars of this specimen indicates they were not used for shearing food or for biting off chunks of prey,” he says. “It took us quite some time to come to the realization that these large teeth were framing narrow slots for filter feeding.”
As confirmation, the researchers found wear on the hidden cusps bordering those slots between the teeth.
The findings offer another example of a broader evolutionary pattern in which body parts (in this case teeth) that evolved for one function are later co-opted for another function. The researchers say they are now examining closely related species from the Charleston, SC, area in search of additional evidence.
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Most modern horses are descendants of recently imported Oriental stallions
Researchers who have analyzed the Y chromosomes of more than 50 horses representing 21 breeds have found that the paternal lines of nearly all modern horses trace to stallions brought to Europe from the Orient over the last 700 years. The findings reported in Current Biology on June 29 reveal the overwhelming influence of breeding schemes driven by strong selection on males.
With the genetic genealogies in hand, it’s now possible to elucidate the origin and relationship of any stallion line in detail, the researchers say.
“Apart from stallion lines in Northern European breeds, all stallion lines detected in other modern breeds derive from more recently introduced Oriental ancestors,” says Barbara Wallner at the University of Veterinary Medicine, Vienna. “Our data therefore illuminate the enormous impact modern horse breeding strategies — characterized by strong selection of males and the import of Oriental stallions — during the past few hundred years had on Y chromosome diversity.”
Y chromosomes are passed down from fathers to their sons. This inheritance pattern makes the Y chromosome a good place to look for clues about the unique history of males of a species. In the new study, the researchers focused on a portion of the Y chromosome that is passed down from one generation to another faithfully. Any changes to that portion of the Y chromosome are the result of new mutations.
“Since random mutations accumulate over time, males who originate from a common patrilineal ancestor will share a particular collection of Y chromosome mutations,” Wallner explains, forming what’s known as a haplogroup.
It had been difficult to reconstruct the history of stallions before because there is extremely low diversity in the Y chromosomes of modern horses to start. The researchers got around that problem by using deep, next-generation DNA sequencing, allowing them to pick up on even the smallest changes.
Their analysis of the 52 Y chromosomes showed that the paternal lineages of various modern horses split much more recently than the domestication of the species, which goes back more than 5,000 years. Apart from a few private Northern European haplotypes, all modern horse breeds included in the study clustered into a roughly 700-year-old haplogroup, transmitted to Europe by the import of Oriental stallions, they report. The haplogroup includes two major subgroups (or clades): the Original Arabian lineage from the Arabian Peninsula and the Turkoman horse lineage from the steppes of Central Asia.
By linking the Y chromosome lineages with genealogical information derived from written records, the researchers say it’s now possible to define Y haplotypes for certain founder stallions. Using this approach, they unraveled the origin of English Thoroughbreds, tracing them to Turkoman founder stallions.
“Our results pave the way for a fine-scaled genetic characterization of stallion lines, which should become routine in the near future,” Wallner says.
The researchers say they now plan to create a global Y chromosome phylogeny to include stallion lineages from more rural horses, which most likely lack any recent Oriental influence.
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Genetic ‘fossils’ reveal long-term viral partnerships in grass
Defective viruses incorporated into grass genomes may adapt to form partnerships with other genome-incorporated viruses in order to complete their life cycle, according to a new PLOS Pathogens study. The findings suggest that partner viruses evolve in concert, enabling them to maintain their relationship over time.
The genomes of animals, plants, and fungi contain stretches of DNA that originated in viruses, integrated into ancient host genomes after infection, and were passed down to host offspring. These viral “fossils” provide an opportunity to study interactions between viruses within host cells on an evolutionary scale.
To better understand viral interactions, Sunlu Chen and colleagues at Hokkaido University, Japan, focused on viral fossils passed down from ancient grasses in the Poaceae grass family. Specifically, they were interested in fossils of viruses known as pararetroviruses (PRVs), which don’t integrate into host DNA as part of their normal life cycle, but may incidentally leave viral “fossil” in host genomes while retaining the ability to complete their life cycle.”
The researchers sequenced and analyzed PRV fossils integrated into modern grass genomes and identified several different PRV species, three of which were found to be defective. These defective species lacked DNA that codes for proteins needed by PRVs to co-opt host cellular machinery and make new copies of the virus, completing the viral life cycle.
To investigate how defective PRVs might still be able to complete their life cycle, the scientists analyzed genetic relationships between the fossil PRV sequences. They found that one defective PRV species may have evolved to form a commensal relationship with a non-defective species, allowing it to use the non-defective protein machinery to complete its life cycle.
Evidence suggests that the other two defective PRVs may have developed a mutualistic partnership, with each species providing complementary protein machinery lacked by the other species.
The research team found that the two species in each partnership have frequently exchanged DNA stretches called noncoding regulatory sequences (NRSs) with each other over time. This concerted evolution has resulted in the partnered species sharing highly similar NRSs, and it appears to have enabled development and maintenance of the partnerships over time.
“Virus fossils in grass genomes revealed that defective pararetrovirus species were prosperous due to compensations of functional deficiencies by partnerships with intact viruses, or with complementary defective viruses.”
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Northern Ireland women to get abortions free on NHS
Ministers make concession ahead of possible Commons rebellion over Queen’s Speech.
Health24.com | Can you recognise the signs of skin cancer?
More than 100 000 South Africans are diagnosed with cancer ever year, with 90% of cancers caused by environmental and lifestyle factors such as diet, smoking and exercise according to the Cancer Association of South Africa (CANSA).
Globally, skin cancer is the fifth most common cancer for men and seventh for women.
With skin cancer the most common type of cancer in the United States, you should learn to spot its early signs, a cancer doctor says.
“Early detection is key. When detected early, most skin cancers may be effectively treated and are often curable,” said Dr Jeffrey Farma, a surgical oncologist at Fox Chase Cancer Center in Philadelphia.
“Individuals play an important role in early detection,” Farma said in a centre news release. “By being familiar with your own skin markings, like moles, freckles and blemishes, you’re likely to notice any changes.”
Recommendation
Have your skin checked yearly by a physician or dermatologist, and check your own skin for signs of skin cancer by using a mirror every month.
Using the ABCDE rule of skin cancer can help identify potential problems, including the most deadly form of skin cancer, melanoma, he said.
A for Asymmetry. Melanoma lesions are often not symmetrical in shape, while benign moles are usually symmetrical.
B for Border. Benign moles usually have smooth, even borders, while melanoma lesions usually have irregular borders that are difficult to define.
C for Colour. A mole with more than one colour (blue, black, brown, tan, etc.) or the uneven distribution of color can sometimes be a warning sign of melanoma. Benign moles are usually a single shade of brown or tan.
D for Diameter. Melanoma lesions are often more than 6 millimetres in diameter, about the size of a pencil eraser.
E for Evolution. The evolution of your moles is important. Knowing what is normal for you could save your life.
“If a mole or marking has gone through recent changes in colour and/or size, bring it to the attention of your doctor immediately so he or she can determine the cause,” Farma said. “Remember that skin cancer affects people of all skin tones, no matter what their complexion.”
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Health24.com | Suffering from incontinence? Acupuncture might help
Acupuncture has been a part of Chinese medicine for more than 3 000 years, and is becoming an often-used technique in today’s world of alternative medicine.
The technique has received mixed reviews in two new studies from China – one focusing on incontinence and the other on a cause of female infertility.
A research team found acupuncture did improve symptoms of stress incontinence – an involuntarily loss of urine, such as when a woman sneezes or coughs.
But in a separate study, another team of researchers determined that acupuncture did not help women who were infertile because of polycystic ovary syndrome (PCOS). Women with PCOS have a hormonal imbalance that keeps them from releasing an egg (ovulating) during the menstrual cycle.
Key element of Chinese medicine
Both studies and the editorial were published online in the Journal of the American Medical Association.
Acupuncture is a key element of traditional Chinese medicine. It involves inserting thin needles into the skin to stimulate specific body points. Previous research has found it might benefit constipation, depression and morning sickness, among other problems. And some research has found it helpful to boost fertility when the problem is not due to polycystic ovary syndrome, the researchers said.
“The research on acupuncture for stress incontinence suggests that acupuncture could be a reasonable and low-risk approach to try before attempting riskier, more invasive treatment such as surgery,” said David Shurtleff. He’s deputy director at the US National Center for Complementary and Integrative Medicine and co-author of an editorial commenting on the two studies.
For infertility due to polycystic ovary syndrome, however, Shurtleff said acupuncture has not been found effective. He suggested patients consider other options.
More research needed
For the incontinence study, researchers randomly assigned about 500 women to 18 real or sham electroacupuncture sessions – acupuncture involving electrical stimulation. The average age of the women was 55, and the half-hour appointments occurred over six weeks. The needles were placed near the small of the back and the back part of the pelvis between the hips.
At six weeks, women who received the real acupuncture had less urine leakage, the study found. These results persisted for another 24 weeks without treatment.
Measuring incontinence over 72 hours, the researchers also found that nearly two-thirds who received real acupuncture had had a decrease of 50% or more in the amount of urine leakage.
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The treatment may work in a number of ways, said study leader Dr Baoyan Liu, a researcher at the China Academy of Chinese Medical Sciences in Beijing.
Acupuncture may strengthen the pelvic floor muscles, among other things, he said. This “may also account for the [persistent] effect” after treatment ended, he added.
Fewer side effects
Liu can’t say if acupuncture would be better than drugs to treat incontinence, as the researchers did not compare acupuncture to drugs. However, acupuncture may have fewer side effects than drug treatment, he noted.
The other trial involved 1 000 women with polycystic ovary syndrome, a condition that affects 5% to 10% of women of reproductive age, according to background notes with the study.
Participants were randomly assigned to one of four groups: real acupuncture plus clomiphene, a drug used to induce ovulation; fake acupuncture plus clomiphene; real acupuncture plus a placebo drug, and fake acupuncture plus the placebo. The drug or placebo were taken for five days each menstrual cycle, for up to four cycles.
Acupuncture made no difference, with about 22% of each group delivering a live baby, according to the study. The corresponding author is Dr Xiao-Ke Wu, who’s with the department of obstetrics and gynaecology at Heilongjiang University of Chinese Medicine in Harbin.
However, the live birth rate was much higher in women treated with clomiphene, which was expected. While 29% of those who took the drug delivered a baby, only 15% of those on a placebo did, the study found.
The researchers concluded that acupuncture won’t help infertility in women with polycystic ovary syndrome.
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Health24.com | Could working night shift damage your DNA?
When people work night shift, their bodies might have a reduced capacity to repair everyday damage to cells’ DNA, a small study hints.
Reduced ability to repair DNA damage
The research found that people excreted lower levels of a chemical called 8-OH-dG when they worked at night. That might be a sign that the body’s ability to repair DNA damage is diminished.
While this is all theoretical, a number of studies have tied shift work to higher risks of obesity, diabetes, heart disease and certain cancers.
The new findings might point to one reason for those risks, said lead researcher Parveen Bhatti, of the Fred Hutchinson Cancer Research Center, in Seattle.
He explained that 8-OH-dG is excreted in the urine when the body repairs DNA damage that occurs during normal body processes.
“So we think lower clearance [of 8-OH-dG] likely reflects a reduced ability to repair DNA damage,” Bhatti said.
“Over time, such DNA damage might contribute to cancer or other diseases,” Bhatti added.
And, he said, the whole process might be due to insufficient levels of melatonin – a hormone that helps regulate the body’s internal “clock”.
Not clear how melatonin fits in
The brain churns out melatonin in response to darkness, and night-shift workers tend to have lower melatonin levels compared to people who work during the day.
However, a researcher who reviewed the study was cautious about interpreting it.
“The results are interesting,” said Kathryn Reid, who studies sleep and circadian rhythms at Northwestern University Feinberg School of Medicine, in Chicago.
“But they didn’t link shift work to actual DNA damage,” Reid said. And it’s not really clear, she added, how melatonin fits in.
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“This doesn’t show that it’s cause-and-effect,” Reid noted.
The findings, reported in the journal Occupational & Environmental Medicine, are based on 50 men and women who worked the night shift in health care jobs.
More research needed
Overall, Bhatti’s team found, the workers had lower levels of 8-OH-dG in their urine when they worked at night, versus nights where they were able to sleep.
Bhatti said the results bolster an earlier study in which his team followed 223 workers – including the 50 in this one. There, the researchers found that workers’ 8-OH-dG levels were lower during daytime sleep, versus nighttime sleep.
The researchers also saw evidence that lower melatonin levels correlated with lower 8-OH-dG. (The 50 workers in the latest study were those who’d shown the biggest drop in melatonin during night work versus night sleep.)
“We think melatonin might be driving this,” Bhatti said.
He acknowledged, though, that his findings so far don’t prove that.
“I’d like to do a trial where we give melatonin to shift workers with low melatonin levels, then see if it affects this biomarker,” Bhatti said, referring to 8-OH-dG.
Maintaining a healthy lifestyle
But until more research is done, he does not suggest shift workers use melatonin supplements in the hopes of preventing DNA damage.
“I’m cautious about melatonin supplements,” Bhatti said. “They’re not regulated by the Food and Drug Administration. You don’t know how much melatonin you’re getting, or what kinds of fillers are being used.”
Plus, Reid added, melatonin can make people feel groggy, which is probably not a good idea for workers who need to be alert at night.
For now, Bhatti suggested that shift workers be “extra vigilant” about maintaining a healthy lifestyle – eating a balanced diet, not smoking and getting regular exercise.
Unfortunately, he added, eating well and exercising can be challenging for shift workers.
“That’s where I think employers can help,” Bhatti said. “They can try to provide access to healthy food and more opportunities for employees to exercise.”
Fin24 recently reported that the biggest fear of up to 92% of South African employees is losing their job, which means that most of us would be careful about saying no to night shift work.
Read more:
Get a nightly dose of darkness
Night shifts boost breast cancer risk
Night shift may boost black women’s diabetes risk
Health24.com | What are the ingredients of a pleasing smile?
A previous Health24 article singled out the smiles of Marilyn Monroe, Julia Roberts and Leonardo Da Vinci’s Mona Lisa. But what exactly are the characteristics of these famous smiles that have captivated us through the centuries?
Less is probably more when it comes to a convincing smile, a new study finds.
Findings from the study were published online in the journal PLoS One.
Balance is key
More than 800 people were shown a series of 3D computer-animated smiles and asked to rate them. The smiles differed in features such as amount, mouth angle, symmetry and how many teeth were shown.
Bigger smiles that showed more teeth tended to be rated as less effective, genuine or pleasant. Successful smiles were those with a pleasing balance of teeth, mouth angle and amount of smile, the investigators found.
The study team – led by Nathaniel Helwig from the University of Minnesota – also found that smiles were rated as more successful if they developed symmetrically on the left and right side of the face.
The findings could help guide facial reanimation surgery and rehabilitation for people with stroke and other medical conditions that affect facial expressions, the researchers said.
The Health24 article mentioned above lists the following five important considerations when aiming for the perfect smile:
- The width of the smile.
- The colour of your teeth
- Not showing too much teeth
- Not showing too much gum
- Being natural
Read more:
A smile can lead to new relationships
