Marijuana might cause new cell growth in the brain
22:00 13 October 2005 by Kurt Kleiner
"A synthetic chemical similar to the active ingredient in marijuana makes new cells grow in rat brains. What is more, in rats this cell growth appears to be linked with reducing anxiety and depression. The results suggest that marijuana, or its derivatives, could actually be good for the brain.
In mammals, new nerve cells are constantly being produced in a part of the brain called the hippocampus, which is associated with learning, memory, anxiety and depression. Other recreational drugs, such as alcohol, nicotine and cocaine, have been shown to suppress this new growth. Xia Zhang of the University of Saskatchewan in Saskatoon, Canada, and colleagues decided to see what effects a synthetic cannabinoid called HU210 had on rats' brains.
They found that giving rats high doses of HU210 twice a day for 10 days increased the rate of nerve cell formation, or neurogenesis, in the hippocampus by about 40%."
Followers
Wednesday, September 22, 2010
Weed =/= cancer
By Marc Kaufman
Washington Post Staff Writer
Friday, May 26, 2006
"The largest study of its kind has unexpectedly concluded that smoking marijuana, even regularly and heavily, does not lead to lung cancer.
The new findings "were against our expectations," said Donald Tashkin of the University of California at Los Angeles, a pulmonologist who has studied marijuana for 30 years.
"We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use," he said. "What we found instead was no association at all, and even a suggestion of some protective effect."
Federal health and drug enforcement officials have widely used Tashkin's previous work on marijuana to make the case that the drug is dangerous. Tashkin said that while he still believes marijuana is potentially harmful, its cancer-causing effects appear to be of less concern than previously thought.
Earlier work established that marijuana does contain cancer-causing chemicals as potentially harmful as those in tobacco, he said. However, marijuana also contains the chemical THC, which he said may kill aging cells and keep them from becoming cancerous.
Tashkin's study, funded by the National Institutes of Health's National Institute on Drug Abuse, involved 1,200 people in Los Angeles who had lung, neck or head cancer and an additional 1,040 people without cancer matched by age, sex and neighborhood.
They were all asked about their lifetime use of marijuana, tobacco and alcohol. The heaviest marijuana smokers had lighted up more than 22,000 times, while moderately heavy usage was defined as smoking 11,000 to 22,000 marijuana cigarettes. Tashkin found that even the very heavy marijuana smokers showed no increased incidence of the three cancers studied.
"This is the largest case-control study ever done, and everyone had to fill out a very extensive questionnaire about marijuana use," he said. "Bias can creep into any research, but we controlled for as many confounding factors as we could, and so I believe these results have real meaning."
Tashkin's group at the David Geffen School of Medicine at UCLA had hypothesized that marijuana would raise the risk of cancer on the basis of earlier small human studies, lab studies of animals, and the fact that marijuana users inhale more deeply and generally hold smoke in their lungs longer than tobacco smokers -- exposing them to the dangerous chemicals for a longer time. In addition, Tashkin said, previous studies found that marijuana tar has 50 percent higher concentrations of chemicals linked to cancer than tobacco cigarette tar.
While no association between marijuana smoking and cancer was found, the study findings, presented to the American Thoracic Society International Conference this week, did find a 20-fold increase in lung cancer among people who smoked two or more packs of cigarettes a day.
The study was limited to people younger than 60 because those older than that were generally not exposed to marijuana in their youth, when it is most often tried."
Washington Post Staff Writer
Friday, May 26, 2006
"The largest study of its kind has unexpectedly concluded that smoking marijuana, even regularly and heavily, does not lead to lung cancer.
The new findings "were against our expectations," said Donald Tashkin of the University of California at Los Angeles, a pulmonologist who has studied marijuana for 30 years.
"We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use," he said. "What we found instead was no association at all, and even a suggestion of some protective effect."
Federal health and drug enforcement officials have widely used Tashkin's previous work on marijuana to make the case that the drug is dangerous. Tashkin said that while he still believes marijuana is potentially harmful, its cancer-causing effects appear to be of less concern than previously thought.
Earlier work established that marijuana does contain cancer-causing chemicals as potentially harmful as those in tobacco, he said. However, marijuana also contains the chemical THC, which he said may kill aging cells and keep them from becoming cancerous.
Tashkin's study, funded by the National Institutes of Health's National Institute on Drug Abuse, involved 1,200 people in Los Angeles who had lung, neck or head cancer and an additional 1,040 people without cancer matched by age, sex and neighborhood.
They were all asked about their lifetime use of marijuana, tobacco and alcohol. The heaviest marijuana smokers had lighted up more than 22,000 times, while moderately heavy usage was defined as smoking 11,000 to 22,000 marijuana cigarettes. Tashkin found that even the very heavy marijuana smokers showed no increased incidence of the three cancers studied.
"This is the largest case-control study ever done, and everyone had to fill out a very extensive questionnaire about marijuana use," he said. "Bias can creep into any research, but we controlled for as many confounding factors as we could, and so I believe these results have real meaning."
Tashkin's group at the David Geffen School of Medicine at UCLA had hypothesized that marijuana would raise the risk of cancer on the basis of earlier small human studies, lab studies of animals, and the fact that marijuana users inhale more deeply and generally hold smoke in their lungs longer than tobacco smokers -- exposing them to the dangerous chemicals for a longer time. In addition, Tashkin said, previous studies found that marijuana tar has 50 percent higher concentrations of chemicals linked to cancer than tobacco cigarette tar.
While no association between marijuana smoking and cancer was found, the study findings, presented to the American Thoracic Society International Conference this week, did find a 20-fold increase in lung cancer among people who smoked two or more packs of cigarettes a day.
The study was limited to people younger than 60 because those older than that were generally not exposed to marijuana in their youth, when it is most often tried."
Lets get to it...
"Heavy Marijuana Use Doesn't Damage Brain
Analysis of Studies Finds Little Effect From Long-Term Use
By Sid Kirchheimer
WebMD Health News
July 1, 2003 -- Long-term and even daily marijuana use doesn't appear to cause permanent brain damage, adding to evidence that it can be a safe and effective treatment for a wide range of diseases, say researchers.
The researchers found only a "very small" impairment in memory and learning among long-term marijuana users. Otherwise, scores on thinking tests were similar to those who don't smoke marijuana, according to a new analysis of 15 previous studies.
In those studies, some 700 regular marijuana users were compared with 484 non-users on various aspects of brain function -- including reaction time, language and motor skills, reasoning ability, memory, and the ability to learn new information.
Surprising Finding
"We were somewhat surprised by our finding, especially since there's been a controversy for some years on whether long-term cannabis use causes brain damage," says lead researcher and psychiatrist Igor Grant, MD.
"I suppose we expected to see some differences in people who were heavy users, but in fact the differences were very minimal."
The marijuana users in those 15 studies -- which lasted between three months to more than 13 years -- had smoked marijuana several times a week or month or daily. Still, researchers say impairments were less than what is typically found from using alcohol or other drugs."
Analysis of Studies Finds Little Effect From Long-Term Use
By Sid Kirchheimer
WebMD Health News
July 1, 2003 -- Long-term and even daily marijuana use doesn't appear to cause permanent brain damage, adding to evidence that it can be a safe and effective treatment for a wide range of diseases, say researchers.
The researchers found only a "very small" impairment in memory and learning among long-term marijuana users. Otherwise, scores on thinking tests were similar to those who don't smoke marijuana, according to a new analysis of 15 previous studies.
In those studies, some 700 regular marijuana users were compared with 484 non-users on various aspects of brain function -- including reaction time, language and motor skills, reasoning ability, memory, and the ability to learn new information.
Surprising Finding
"We were somewhat surprised by our finding, especially since there's been a controversy for some years on whether long-term cannabis use causes brain damage," says lead researcher and psychiatrist Igor Grant, MD.
"I suppose we expected to see some differences in people who were heavy users, but in fact the differences were very minimal."
The marijuana users in those 15 studies -- which lasted between three months to more than 13 years -- had smoked marijuana several times a week or month or daily. Still, researchers say impairments were less than what is typically found from using alcohol or other drugs."
Subscribe to:
Posts (Atom)