Hot flushes – the inconvenient, irritating reality of menopause and what to do about it
The cause of flushes is unknown, but remedies are available. In other news, researchers find link between Chinese herbal remedies and liver cancer, and dyslexia may be related to hidden tiny light receptor cells in the eye
The possible causes and cures for hot flushes
They strike at the most inopportune times: during meetings, dinner, in bed. The face flushes, the heart races. Fingers tingle and perspiration washes over the body. They’re hot flushes, and for more than 70 per cent of women, they’re an inconvenient and sometimes unpleasant reality of menopause.
What’s the cause? Carolyn Crandall, a professor of medicine at University of California at Los Angeles’ David Geffen School of Medicine, has bad news: “We don’t know the answer.”
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The symptoms seem to begin in the hypothalamus, the part of the brain that helps regulate body temperature. Hormonal changes may cause the hypothalamus to tell the body it’s really hot. As a result, it responds by sweating and dilating blood vessels – reactions that usually occur when the body is actually hot.
But it’s not really clear what triggers this process, how to stop it, or even whether a lack of oestrogen, the female sex hormone that is produced in smaller quantities in middle age, is its cause.
Women with a history of smoking, conditions such as depression and anxiety, and high body mass indexes appear to be at higher risk, according to research. There’s no telling how long any particular woman will experience hot flushes; on average, they last seven years – even longer for African American women – and they may persist for a lifetime. Recent studies show Chinese women are less likely to experience them.
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Traditional hormone replacement therapy, or HRT, and bioidentical hormone therapy, which mimics hormones produced by ovaries using plant or animal derivatives, are options for relief.
HRT was common until about 15 years ago, when a major trial suggested it increased women’s risk of heart disease and some breast cancers.
But for a woman who can’t take the heat, there’s no shame in compensating for the oestrogen lost during menopause. “She should not feel bad,” says Crandall, who adds that each woman is the only one who can decide her symptoms are distressing enough to warrant hormone therapy. “If her doctor’s not open to that discussion, she needs to find another one.”
A recent study suggests that five to seven years of traditional hormone therapy may be safe – for certain groups. The study found that women who take HRT for up to seven years had no greater mortality risk than women who did not. This jibes with a position statement by the North American Menopause Society that treatment should be individualised. Women younger than 60 who are within 10 years of the onset of menopause are more likely to benefit from traditional hormone therapy.
The Washington Post
Researchers have uncovered evidence of a link between traditional Chinese herbal remedies and liver cancer across Asia, a study said on Wednesday.
The findings suggest stronger measures are needed to prevent people from consuming chemicals called aristolochic acids (AA), derived from the woody vines of the aristolochia plant family, said the report in the journal Science Translational Medicine.
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The acids can be found in some traditional Chinese medicines that are given during childbirth, to prevent parasites and promote healing.
Researchers tested 98 liver tumours that were stored at hospitals in Taiwan, and found that 78 per cent contained patterns that indicated the cancers “were likely due to contact with the chemicals,” said the study.
Since these acids cause “a well-defined mutational signature,” researchers also looked at 89 samples of liver cancer in China, and found that 47 per cent showed a link to this traditional medicine component.
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In Vietnam, five out of 26 tumours studied were a match (19 per cent), along with five out of nine from other countries in Southeast Asia (56 per cent).
The link was far less common in North America (five per cent of 209 liver cancers studied) and 1.7 per cent of the 230 looked at from Europe.
In 2003, Taiwan banned some herbal preparations using the plants after it was discovered that aristolochic acids could cause kidney failure and urinary tract cancers.
However, there is no outright ban in China or Taiwan, and “only specific plants, rather than any plant and product containing AA or its derivatives, are regulated,” making it hard for consumers to avoid them, the report said.
AFP
Scientists say dyslexia related to hidden tiny light-receptor cells in the human eye
There is some positive news for the 700 million people in the world known to suffer from dyslexia – about one in 10 of the global population. French scientists say they may have found a cause for this reading disability hidden in tiny light-receptor cells in the human eye – and it may be treatable.
In people with dyslexia, the cells were arranged in matching patterns in both eyes, which may be to blame for confusing the brain by producing “mirror” images, the co-authors wrote in the journal Proceedings of the Royal Society B.
In non-dyslexic people, the cells are arranged asymmetrically, allowing signals from the one eye to be overridden by the other to create a single image in the brain.
“Our observations lead us to believe that we indeed found a potential cause of dyslexia,” study co-author Guy Ropars of the University of Rennes, said.
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It offers a “relatively simple” method of diagnosis: looking into a subject’s eyes.
“The discovery of a delay [of about one-hundreth of a second] between the primary image and mirror image in the opposing hemispheres of the brain, allowed us to develop a method to erase the mirror image that is so confusing for dyslexic people” – using an LED lamp.
Like being left- or right-handed, human beings also have a dominant eye.
As most of us have two eyes, which record slightly different versions of the same image, the brain must select one of the two, creating a “non-symmetry.”
Many more people are right-eyed than left, and the dominant eye has more neural connections to the brain than the weaker one.
Image signals are captured with rods and cones in the eye – the cones being responsible for colour.
Most cones, which come in red, green and blue, are found in a small spot at the centre of the cornea known as the fovea. But there is a small hole (about 0.1-0.15 millimetres in diameter) with no blue cones.
In the study, Ropars and colleague Albert le Floch spotted a difference between the arrangement of cones between the eyes of dyslexic and non-dyslexic people. In non-dyslexic people, the blue cone-free spot in one eye – the dominant one – was round and in the other eye unevenly shaped. In dyslexic people, both eyes have the same, round spot, which translates into neither eye being dominant, they found.
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“The lack of asymmetry might be the … basis of reading and spelling disabilities,” said the authors.
Dyslexic people make so-called “mirror errors” in reading, for example confusing the letters “b” and “d”.
“For dyslexic students their two eyes are equivalent and their brain has to successively rely on the two slightly different versions of a given visual scene,” they added.
They used an LED lamp, flashing so fast that it is invisible to the naked eye, to “cancel” one of the images in the brains of dyslexic trial participants while reading.
In initial experiments, dyslexic study participants called it the “magic lamp,” said Ropars, but further tests are required to confirm the technique really works. AFP
