Saturday, May 05, 2007

Marijuana both good and bad?

A chemical found in cannabis could be used to treat schizophrenia with fewer side-effects than existing antipsychotic drugs, research suggests. Though cannabis can provoke psychotic symptoms, these effects appear to be caused chiefly by one of its components; and another compound that damps down its effects has potential as a medicine, scientists said.

The findings, to be announced at a conference that opens in London today, offer a possible explanation for anecdotal reports of increasing cases of psychosis and schizophrenia triggered by the drug. As concentrations of tetra-hydracannabinol (THC), the main psychoactive element that can provoke psychosis, have risen, levels of the beneficial chemical, cannabidiol (CBD) have fallen. This could mean that users are being exposed to higher doses of the damaging chemical, while receiving less CBD, which tends to balance THC's effects.

"There is a possibility that there are good guys and bad guys in cannabis," said Markus Leweke, of the University of Cologne. "THC is the bad guy, but there is a small body of literature that suggests CBD may prevent the induction of psychotic symptoms. Our study supports that view." There are no official statistics on how cannabis use is affecting levels of mental illness, but there is growing evidence that the drug can induce psychosis and schizophrenia.

Scientists also report anecdotal evidence that more young people are developing schizophrenia as a result of using the drug. Robin Murray of the Institute of Psychiatry, said: "There is no robust evidence on cannabis-induced psychosis, but there are a lot of anecdotal reports it is increasing. Psychiatrists specialising in adolescence who used to have no interest in psychosis are now holding clinics with lots of patients with psychosis related to drug use." Comparisons of US drugs seizures in the 1960s and the 1990s show that THC levels have increased significantly as growers breed plants with more powerful psychoactive effects, and it is known that CBD content goes down as THC increases.

In the research, which will be presented at the Institute of Psychiatry's international conference on cannabis and mental health, Dr Leweke investigated the effects of CBD on 42 patients with acute schizophrenia. Some were given CBD, while others received a standard anti-psychotic drug called amisulpride. Both groups had fewer psychotic symptoms, but the CBD group also experienced fewer side-effects. Common side-effects of amisulpride include weight gain, sexual dys-function and liver problems.

In two studies to be presented to the conference, scientists have found new evidence linking THC to psychosis. Philip McGuire and Zerrin Atakan, of the Institute of Psychiatry, used functional magnetic resonance imaging to scan the brains of patients who took THC, and found that it reduced activity in a region involved in inhibiting inappropriate behav-iour. As activity in this region dropped, the subjects became progressively more paranoid. A second study, by Deepak Cyril D'Souza, of Yale University, found that THC administered intravenously worsened the symptoms of patients with schizophrenia.


Cure for osteoporosis?

Millions of women could be protected against life-threatening hip fractures by a once-a-year treatment with a new drug. More than 14,000 women die every year in Britain after breaking their hips as a result of the bone-thinning disease osteoporosis, which affects up to three million people. The new treatment cuts the risk of such fractures by more than 40 per cent. Almost half a million women, mostly aged over 50, are prescribed drugs for the disease. Well-known sufferers include Rosalind Shand, the mother of the Duchess of Cornwall, Elizabeth Taylor and Doris Lessing. the novelist.

The 15-minute treatment means that women can be protected against developing brittle bones without having to remember to take pills regularly. Poor adherence to treatment is a major problem in the development of osteoporosis. The new drug, zoledronic acid (Aclasta) has been tested on almost 8,000 women in a trial that included patients from Aberdeen, Sheffield, Liverpool and Glasgow. They were given annual infusions of either Aclasta or a placebo, and followed for three years. The results, published in the New England Journal of Medicine, showed a 70 per cent reduction in fractures of the vertebrae of the spine, and a 41 per cent reduction in hip fractures. Breaks elsewhere in the body, such as the wrist, were reduced by 25 per cent.

There are more than 60,000 hip and 120,000 vertebral fractures every year in Britain, according to the National Osteoporosis Society. One in five of those who suffer a hip fracture dies within three months. Drugs for the disease, including the class called bisphosphonates to which Aclasta belongs, are given normally as pills that are taken daily or weekly. They are effective but do not always achieve their full potential because women stop taking them. One study in the US of bisphosphonate users who were followed for two years, found that only 43 per cent took the full course prescribed to them.

Professor Dennis Black, of the University of California, who led the new study, and his co-authors concluded: "A regimen of infusions once a year appears to ensure that patients will have a full treatment effect for at least 12 months. In contrast, many patients who receive prescriptions for oral bisphosphonates stop treatment, and most appear to be taking less than 80 per cent of their prescribed pills by 12 months." The National Osteoporosis Society welcomed this "exciting new treatment", saying that when it is available, it will add to the choice of drug treatments available for people at risk of breaking a bone due to osteoporosis. "An annual intravenous preparation may prove to be a convenient, cost-effective strategy," the society said.

Richard Eastell, Professor of Bone Metabolism at the University of Sheffield and a co-author of the study, said that the findings provided potential good news for thousands of women. "The ability to only have the treatment once a year does mean that it simplifies the whole regimen. There is no doubt that Aclasta reduces vertebral fracture, hip fracture and other breaks," he said.

David Reid, of the University of Aberdeen and a co-author, said that the hip fracture data was particularly relevant. "Preventing hip fractures remains the holy grail of treating osteoporosis, as we know that six months after a hip fracture, nearly a fifth of patients will be dead. Reducing hip fractures by 41 per cent is therefore highly clinically significant."

Professor Juliet Compston of Cambridge University, a specialist in osteoporosis, said that the intravenous administration of Aclasta ensured that treatment was delivered correctly. The side-effects of the infusion appeared to be manageable, although Professor Compston was concerned about a rise in atrial fibrillation (a heart rhythm disturbance) in some patients, but this could be due to chance, she said.

Aclasta is made by Novartis, which funded the study. It is currently licensed for use in Britain in the treatment of Paget's disease of the bone, and a 100ml infusion containing 5mg of the drug (the dose in the trial) costs the NHS 284 pounds.


Sunscreen 'last line of defence'

As someone with very fair skin, I myself have always thought that staying in the shade was the way to go

Cancer experts say they won't tamper with Australia's punchy "Slip, Slop, Slap" anti-sun slogan in light of new research which downplays the role of sunscreen. An international review of sun protection has warned that protective clothing and hats are a far superior way to guard against skin cancer and the ageing effects of the sun. The study, published in the prestigious Lancet journal, relegates sunscreens to the last line of defence, saying they have potential to be "abused" so users can spend more time in the sun.

International reports have suggested a rethink of the world-famous 26-year-old Australian slogan which urges people to slip on a shirt, slop on sunscreen, and slap on a hat, in that order. "That would mean changing it to 'Slip, Slap, Slop,' to put sunscreen at the back of the line, but it's probably not smart to fiddle with such a successful slogan," said Ian Olver, head of Cancer Council Australia, which manages the sun smart campaign. "You'd risk throwing the baby out with the bath water and losing the whole message, and that would be a disaster."

But Prof Olver said the organisation agreed the priorities for sun protection had changed, with protective clothing and hats clearly far superior to screens. People relied on sunscreen alone too often, largely due to the "brown is beautiful" pro-tanning messages still promoted in the mass media, Prof Olver said. Sunscreen was typically applied too sparingly, too infrequently and rubbed in too thoroughly "which can essentially rub it off the skin all together", he said. "We definitely agree that it's the last line of defence, but it's a matter of changing the message without changing the slogan that accompanies it."

The new study by Swiss dermatologists tested all types of sun protection and awarded tightly woven, thick clothing the top prize. Items made from denim, wool and polyester offered the best protection, while cotton, linen and acetate were far less effective. Clothes that had shrunk after washing were also better than materials which were wet or had been stretched or bleached, according to dermatologist Stephan Lautenschlager, from Triemli Hospital in Zurich.



Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.


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