The Teen Brain on Weed

April 25, 2015 by

April 24, 2015

By Medical Discovery News

A brain

It is now legal to use marijuana (recreationally and/or medically) in more than 20 states and the District of Columbia, and as more places debate legalizing the substance, more people are asking about its consequences on human health. There are many myths and misconceptions out there, but this is what science has to say about the subject.

As with all substances, the health effects depend on the potency, amount, and a person’s age. An independent scientific committee in the United Kingdom evaluated how harmful various drugs were based on 16 criteria and ranked heroin, crack cocaine, and methamphetamine as the most harmful drugs to individuals using them, and ranked alcohol, heroin, and crack cocaine as the drugs that cause the most harm to others. Marijuana ranks eighth, with slightly more than one-quarter the harm of alcohol.

Short-term use is associated with impaired short-term memory, making it difficult to learn and retain information while under the influence. Short-term use can also impair motor coordination, interfering with tasks such as driving. The overall risk of an accident doubles if a person drives soon after using marijuana. In comparison, those with blood alcohol levels above the legal limit are five times more likely to have an accident, and the combination of alcohol and marijuana is higher than either one alone.

Long-term or heavy use is associated with diminished life satisfaction and achievement overall. At high doses, marijuana can cause paranoia and psychosis, and long-term marijuana use increases the risk of developing schizophrenia or other chronic psychotic illnesses. Nine percent of all marijuana users, or 2.7 million people, develop an addiction to it. That figure jumps to 25-50 percent for those who use marijuana daily, and 17 percent of people who begin using marijuana as adolescents become addicted. Cannabis withdrawal syndrome is real and includes symptoms of irritability, sleep disturbance, dysphoria, craving, and anxiety.

Adults who occasionally use marijuana do so with little to no risk, but adolescent brains are not fully developed, making them more vulnerable to the adverse effects of marijuana. Using marijuana during adolescence can alter brain development, causing impaired cognition and lower IQs. This is probably because the active ingredient in marijuana, tetrahydrocannabinol, affects the brain’s ability to make connections between neurons in certain regions of the brain. Adolescent marijuana users also have a smaller hippocampus, which is important in learning and memory, and a less active prefrontal cortex, which is important in cognitive tasks such as planning and problem-solving.

Since acute marijuana intoxication can impair cognitive functions for days, students who use marijuana may function well below their natural abilities, causing academic difficulties. High school dropouts do report higher marijuana usage than their peers. Some evidence suggests that these cognitive impairments could be long-lasting or permanent in long-term users who started at younger ages, which can impact their abilities to succeed academically and professionally.

There is no clear association between long-term marijuana use and any deadly disease, although chronic marijuana smokers have increased rates of respiratory infections and pneumonia and an increased risk of heart attack and stroke. The effects of marijuana on a developing embryo and the effects of second-hand or third-hand marijuana smoke have not been well-studied, but as marijuana legalization continues to be an issue the science behind it will as well.

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Hope for Sickle Cell

September 20, 2014 by

Sept. 19, 2014

By Medical Discovery News

While sickle cell disease has long been studied, a recent discovery revealed that the disease significantly increases the levels of a molecule called sphingosine-1-phosphate (S1P), which is generated by an enzyme called sphingosine kinase 1 (SphK1). Inhibiting the enzyme SphK1 was found to reduce the severity of sickle cell disease in mice, which will hopefully lead to new drugs that target SphK1in order to treat sickle cell disease in humans.

Sickle cell disease is caused by a change in the gene that is responsible for a type of hemoglobin, the protein molecule in red blood cells that carries oxygen. This tiny change results in hemoglobin clumping together, changing the shape of red blood cells.

The name for sickle cell disease actually comes from misshapen red blood cells. Rather than being shaped like a disk, or a donut without a whole, sickle cells are shaped like a crescent, sort of bending over on themselves. The normal shape is critical to red blood cells’ ability to easily travel through blood vessels and deliver oxygen to cells and tissues. Sickle cells become inflexible and stick to each other, blocking the flow of blood through blood vessels.

Symptoms of the disease begin to appear at about four months of age. Normally, red blood cells live for about 120 days. Sickle cells only survive 10-20 days. Although the bone marrow tries to compensate for the rapid loss of red blood cells, it cannot keep up. The disease causes pain, anemia, organ damage, and possibly infections.

Although the symptoms and their severity vary, most people with sickle cell disease will have periodic crises lasting hours or days. Symptoms include fatigue, paleness, shortness of breath, increased heart rate, jaundice, and pain. Long-term damage can occur in the spleen, eyes, and other organs, and sickle cell disease increases the risk of stroke. People who only inherit one copy of the sickle cell hemoglobin gene have a milder case of the disease than those who inherit two copies, one from each parent.

Current treatments only reduce the number and the severity of crises using hydroxyrurea, blood transfusions, pain medications, and antibiotics. As the disease advances, dialysis, kidney transplants, eye surgeries, gall bladder removal, and other treatments may be necessary. The only cure for the disease is a bone marrow transplant, which is not an option for everyone.

So it’s pretty exciting that when scientists found that levels of S1P were elevated in mice with sickle cell disease, they inhibited the enzyme SphK1 to reduce the levels of S1P. As a result, red blood cells lived longer and had less sickling. The mice also had less inflammation and tissue damage, which would reduce damage to red blood cells and prevent symptoms of the disease. When they engineered sickle cell disease mice without the gene for the enzyme SphK1 that makes S1P, again the mice had less sickling and symptoms.

How does S1P influence sickling? Apparently, it binds directly to hemoglobin and reduces its ability to collect and carry oxygen, which causes the characteristic folding of cells. S1P has other roles in the body, so it is unknown whether inhibitors to SphK1 can safely and effectively be used in humans to treat sickle cell disease.

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A Top 10 List To Die For

September 13, 2013 by

Sept. 13, 2013

By Medical Discovery News

How are you going to die?

The Centers for Disease Control would answer that life expectancy depends greatly on where someone lives. Life expectancy in the United States ranks 40th in the world with 77.97 years.That addresses when someone might die but what about how? Most likely, it will be from one of these top 10 causes, based on how many Americans they kill each year.

10) Suicide – 38,285. Many factors are now known to influence suicide: mental illnesses, genetics, certain pharmaceuticals, traumatic brain injuries, drug and alcohol abuse, and chemical or hormonal imbalances. To decrease these rates, education about the signs preceding suicide and accessible treatment is necessary.

9) Kidney Disorders – 45,731. Although dialysis can help people survive a little longer without a kidney, it is no cure. Kidney damage can occur from infection, high blood pressure, or toxic reactions to drugs, leading to chronic kidney disease that affects more than 26 million Americans.

8) Influenza and Pneumonia – 53,667. Both these diseases mostly affect the very old, very young, or those with immune system problems. This figure could be lowered with vaccinations.

7) Diabetes – 73,282. The rate of diabetes is increasing, with one in 500 children being diagnosed, corresponding to trends in obesity, diet, exercise, and aging. Lifestyle changes could decrease diabetes rates.

6) Alzheimer’s – 84,691. This form of dementia affects older adults, mostly over 60, and is caused by the build-up of beta-amyloid protein plaques in the brain. There is currently no cure.

5) Accidents – 122,777. The leading cause of accidental deaths depends on age. For children and young adults it’s car accidents, adults over 35 are most likely to accidentally overdose on drugs, and for those over 65 it’s most likely to be related to a fall.

4) Stroke – 128,931. A stroke occurs when an area of the brain does not receive oxygen due to a ruptured or blocked blood vessel. Those with high blood pressure, diabetics, smokers, and alcoholics are at the highest risk. The good news is that deaths from strokes decreased by almost 45 percent in 10 years but still leads to more than 250,000 hospitalizations yearly.

3) Chronic Lower Respiratory Diseases – 143,382. These diseases of the lungs and airways include bronchitis and emphysema, although the latter kills 20 times more than the former. Smoking is the leading cause of this condition.

2) Cancer – 575,313. Lung, colon, breast, pancreatic, and prostate cancers have the most victims out of more than 200 different types affecting more than 60 different organs. Another piece of good news is that five-year survival rates have increased about 15 percent since the 1970s.

1) Heart Disease – 596,339. Advances in science have improved care, reducing these deaths by 18 percent in 10 years. However, as 25 percent of adults have high blood pressure, 67 percent are overweight, and 20 percent smoke, Americans have plenty of risk factors to improve on.

The United States has maintained its leadership role in biomedical science and needs to continue this in the future. Support biomedical research – your life may depend on that next scientific advance.

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Stroke Recovery . . . Later

November 11, 2012 by

By Medical Discovery News

Nov. 10, 2012

Aubrey Plaza - "Safety Not Guaranteed" Greenroom Photo Op - 2012 SXSW Music, Film + Interactive Festival

Known for her snarky comments and deadpan delivery on NBC’s “Parks and Recreation,” 28-year-old actress Aubrey Plaza has a clear complexion, luminous brown eyes, and quick wit – the very picture of health. But eight years ago, she was talking with friends when she suddenly lost feeling in her right arm, then her whole right side. She tried to speak, but couldn’t form the words. She suffered a stroke, which she has now fully recovered from.

Stroke symptoms include sudden numbness or tingling, loss of movement, vision changes, difficulty speaking, confusion, loss of balance, and severe headache, although victims don’t necessarily show all the symptoms. And while most stroke patients are past midlife, even those in their 20s, like Plaza, can be at risk.

Stroke victims increase their chances of a full recovery if they can get treatment within three hours of the first symptoms. But for that to happen, a person must get to a hospital within the first hour to give doctors enough time to evaluate their condition and administer the right drugs. Stretching that window could buy a lot of time for more people.

In lab tests, a compound called dalfampridine, also known as Ampyra, can expand the treatment window not by mere hours, but by weeks. Today’s leading drug treatment is tissue plasminogen activator or t-PA. It’s used to treat the 80 percent of stroke victims who have ischemic strokes, caused by a blood clot blocking a blood vessel in the brain. T-PA dissolves the clot, but must be given within three hours.

By contrast, the new drug under study, Ampyra, improved motor function in rats that had suffered a stroke at least four weeks prior. All four limbs had better motor function, and rats given higher doses improved even more. A clinical trial is planned with a small number of human stroke patients who suffered a stroke at least 6 months earlier.  By then patients’ recoveries have usually hit a plateau, so improvements over the course of the study can be attributed to Ampyra.

The drug is already approved for helping multiple sclerosis patients walk. If it can do the same for stroke victims, it’ll be the first effective treatment other than physical therapy to restore motor function long after a devastating stroke.

Another drug researchers are studying is Gleevec. Like Ampyra, it can stretch the treatment window, but to give existing drug, t-PA, more time to work. One of the side effects of t-PA is cerebral bleeding. Researchers recently discovered Gleevec, a leukemia drug, is able to not only stem the bleeding, but stretch the treatment window beyond the three hours t-PA requires.

If both drugs prove effective, they could significantly improve the outcome for stroke patients who are unable to get immediate care.

The benefits of developing stroke therapies are obvious. Over 6 million Americans have had a stroke, and half a million new cases occur each year. More importantly, it’s the leading cause of serious, long-term disability in adults. That’s a heavy burden on the healthcare system and on family caretakers.

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Lifesaving Venom

September 1, 2012 by

By Medical Discovery News

Sept. 1, 2012

Reversing Cerebral Palsy

People have evolved a fear of snakes out of necessity. One bite from a venomous snake can prove fatal, so it’s ironic that a number of remarkable drugs are derived not only from poisonous snakes, but other deadly creatures as well. Researchers increasingly prize this group of animals, believing their venom holds the promise of effective treatments for major disorders ranging from high blood pressure to heart disease to cancer.

Depending on the type of poisonous snake, a bite can cause a drop in platelets and lead to uncontrollable bleeding. Or it can, like the venom of the Brazilian pit viper, incapacitate victims by causing their blood pressure to plummet. But in smaller doses these same characteristics can reverse disease.

One group of drugs, called ACE inhibitors, brings down blood pressure by decreasing chemicals that tighten blood vessels so that blood flows more smoothly. Another drug, called tirofiban, comes from the saw-scaled viper, which has venom that thins the blood and causes victims to bleed out. As a drug, it’s an anticoagulant used to dissolve blood clots in people with a minor or impending heart attack.

Another venom with similar mechanisms comes from the Malayan pit viper, except it also possesses a protein that may dissolve clots for as long as six hours after stroke symptoms start. An international study is targeting this venom’s potential to expand the three-hour window required for current drugs to be effective. Allowing people more time to get to a hospital for evaluation and treatment makes a significant difference on their prognosis.

Other deadly creatures also have lifesaving potential. Scientists are studying the fatal Deathstalker scorpion native to North Africa and the Middle East. Yet, its venom contains Chlorotoxin, which just happens to attach to cancer cells by binding strongly to a cancer-specific protein called matrix metalloproteinase-2. By fluorescently labeling Chlorotoxin, surgeons can easily identify cancer tissues and remove them. Scientists also figured out that by radioactively labeling Chlorotoxin, the toxin targets tumor cells and the radiation kills them.

Another example is Cobratoxin, which Western pharmacists began experimenting with as early as the 1930s on patients with diseases such as multiple sclerosis (MS) and asthma. More recently, a modified form of Cobratoxin has been shown to block the development of induced MS in 90 percent of lab rats. Cobratoxin seems to stimulate a molecule called interleukin 27, which slows an overactive immune response that scientists believe may be causing the disease. A related toxin molecule called Cobrotoxin has been shown in studies to impede the spread of HIV by blocking the receptors the virus uses to infect cells.

While the field of venom study has grown, researchers are concerned that negative environmental impacts on some of the threatened venomous species will limit their work. Ultimately that reduces the number of potential life saving or life changing drugs that are possible.

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