Tag Archives: peripheral arterial disease

Could Genetics Play a Role in Degrees of Addiction?

As a practicing hypochondriac it was of particular interest to me to learn about a research company in, of all places, Iceland, which is making what could be historic advances in medicine through the study of human genetics.

This company, deCODE genetics, is exploiting a most unusual data base: that of the total population of Iceland where excellent records have been kept since Norwegian and Celtic (Scottish and Irish) settlers arrived there about ten centuries ago. Today there are only slightly more than 300 000 Icelanders, of whom 94 percent are descended from the original settlers. For gene searchers this is, apparently, like a gift from heaven.

It is akin to having a vast private laboratory, enabling research on thousands of volunteers uniquely related in a manner which renders the search for genetic clues to future health problems. For example, more than 50,000 Icelanders, that is one-sixth of the population, participated in research into the disposition to smoking and, for smokers, the inherent risks of contracting diseases linked to nicotine.

Now deCODE is coming up with suggestions that, through the study of human genetic makeup, or our DNA, it can be predicted with accuracy that one will be predisposed to a particular kind of illness or even, as in the case of cigarette smoking, particular types of addiction.

The company’s scientists have established “a clear link between a single-letter variant of the human genome (SNP) and susceptibility to nicotine dependence.”

Such addiction can lead, for example, to lung cancer and peripheral arterial disease (PAD), a common and debilitating constriction of the arteries to the legs.

The odds of this happening to a given individual can be calculated using these genetic techniques.

The research, which also studied smokers in New Zealand, Austria, Sweden, Italy, the Netherlands and Spain, revealed that there is correspondence not only between genetic makeup and the likelihood of addiction but also to the approximate number of cigarettes an addict is likely to smoke daily.

DeCODE has also isolated key genes “contributing to major public health challenges from cardiovascular disease to cancer, genes that are providing us with drug targets rooted in the basic biology of disease”.

smoking cigarettesGiven the incidence in South Africa of dermatological problems such as the deadly cutaneous melanoma (CM) and basal cell carcinoma (BCC) it is interesting to learn that it is not only very fair skin, blue or green eyes, freckles, red hair and exposure to ultraviolet light (obviously prevalent in South Africa) that can expose one to CM and BCC.

Scientists at deCODE have discovered that “a novel, tightly-linked pair of single-letter variants” near a certain gene on chromosome 20 and another on chromosome 11 specifically increases our susceptibility to sunburn and hence to its dangers.

All this should be of enormous future use to the medical profession, although one suspects that our health minister, Manto Tshabalala-Msimang, would probably prefer some quackery or other for guidance rather than the research of serious Icelandic scientists.

Interestingly, the company offers a personal, on-line service for those wishing to explore their genome tree or whatever geneticists call these things. Just log on to www.decodeme.com – although I haven’t done this, so I cannot advise you what to expect.

By the way, this little cutting edge company is listed on the Nasdaq in New York and the stock quote is DCGN. This writer holds no shares.

Source: Stephen Mulholland, Dispatch Online

Researchers Identify Genetic Variant Linked To Nicotine Addiction

NIDA Researchers Identify Genetic Variant Linked To Nicotine Addiction And Lung Cancer – Variant Also Increases Risk For Cardiovascular Disease

Scientists have identified a genetic variant that not only makes smokers more susceptible to nicotine addiction but also increases their risk of developing two smoking-related diseases, lung cancer and peripheral arterial disease.

The research was supported by the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health (NIH).

The study, published in the April 3 issue of the journal Nature, “highlights the advances that are being made in genetics research, which can now identify gene variants that increase the risk of complex bio-behavioral disorders,” says NIH Director Dr. Elias Zerhouni. “This finding will help us in our efforts to further reduce the scope and devastating consequences of cigarette smoking.”

“These results suggest for the first time that a single genetic variant not only can predispose to nicotine addiction but may also increase sensitivity to extremely serious smoking-related diseases,” explains NIDA Director Dr. Nora Volkow. “Additionally, it points to potential targets for new smoking-cessation medications that may be more effective at helping smokers to quit.”

The variant is closely linked to two of the known subunits of nicotine receptors, the sites on the surface of many cells in the brain and body that can be bound by nicotine. When nicotine attaches to these receptors in the brain, there are changes in cell activity that results in its addictive effects.Carriers of this genetic variant are more likely than noncarriers to be heavy smokers, dependent on nicotine, and less likely to quit smoking. “The variant does not increase the likelihood that a person will start smoking, but for people who do smoke it increases the likelihood of addiction,” says Dr. Kári Stefánsson, the study’s principal investigator and chief executive officer of deCODE Genetics, a biopharmaceutical company based in Reykjavik, Iceland.

The variant was identified through a technique known as genome-wide association, in which DNA samples (from more than 10,000 Icelandic smokers) were analyzed for the presence of more than 300,000 genetic markers. Subsequent investigation showed that carriers of the variant strongly associated with nicotine dependence were also at increased risk for two smoking-related diseases, peripheral arterial disease and lung cancer. The findings were replicated in populations from five European countries and New Zealand. The researchers estimate that the variant explains 18 percent of cases of lung cancer and 10 percent of cases of peripheral arterial disease in smokers.

Nicotine addictionThe same variant was identified as one that increased risk for lung cancer in two other articles appearing in the April 3rd, 2008, issues of Nature and Nature Genetics, partially funded by two other NIH institutes–the National Cancer Institute and the National Human Genome Research Institute.

For more information on Smoking/Nicotine: http://www.drugabuse.gov/DrugPages/Nicotine.html

The National Institute on Drug Abuse

The National Institute on Drug Abuse is a component of the National Institutes of Health, U.S. Department of Health and Human Services. NIDA supports most of the world’s research on the health aspects of drug abuse and addiction.

The Institute carries out a large variety of programs to inform policy and improve practice. Fact sheets on the health effects of drugs of abuse and information on NIDA research and other activities can be found on the NIDA web site at http://www.drugabuse.gov.

The National Institutes of Health

(NIH) – The Nation’s Medical Research Agency – includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services.

It is the primary Federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.

Cigarette Smoking and Its Impact on Spinal Fusions

Learn About the Prevalence of Cigarette Smoking

According to the American Cancer Society, “48 million adults (25.7 million men and 22.3 million women) were current smokers in the United States in 1997.”

Many of these adult smokers started during their teenage years. Unfortunately, even today people still begin to smoke cigarettes despite published statistics that show its negative impact on health.

The adverse effects of smoking include nicotine addiction, an increased risk of lung and other types of cancer, higher rates of arteriosclerosis (hardening of the arteries) and heart disease, as well as decreased life expectancy.

Cigarettes contain dried tobacco leaves and flavorings, which include more than 4,000 chemicals. Some of these substances are harmless until burned and breathed.

The Spine and Cigarette Smoking

Picture of SpineBone is a living tissue dependent on the functions and support provided by the other body systems. When these systems are not able to perform normally, bone is unable to rebuild itself. The formation of bone is particularly influenced by physical exercise and hormonal activity, both of which are adversely affected by cigarette smoking.

Many smokers have less physical endurance than nonsmokers, mainly due to decreased lung function. Cigarette smoking reduces the amount of oxygen in the blood and increases the level of harmful substances, such as carbon monoxide. This, combined with the effects of smoking on the heart and blood vessels, can limit the benefits from physical activity.

In men and women, cigarette smoking is known to influence hormone function. Smoking increases estrogen loss in women who are perimenopausal or postmenopausal. This can result in a loss of bone density and lead to osteoporosis. Osteoporosis causes bones to lose strength, becoming more fragile. This silent disease is responsible for many spine and hip fractures in the United States.

Spinal Fusion and Cigarette Smoking

Defined Spinal fusion is a surgical procedure used to join bony segments of the spine (e.g. vertebrae). In order for the fusion to heal, new bone growth must occur, bridging between the spinal segments. Sometimes fusion is combined with another surgical technique termed spinal instrumentation. Instrumentation consists of different types of medically designed hardware such as rods, hooks, wires, and screws that are attached to the spine. These devices provide immediate stability and hold the spine in proper position while the fusion heals.

Spinal fusion (also termed arthrodesis) can be performed at the cervical, thoracic, or lumbar levels of the spine. It takes months to heal. Your doctor may order post-operative radiographs (x-rays) to monitor the progress of this healing.

The long-term success of many types of spinal surgery is dependent upon successful spinal fusion. In fact, if the fusion does not heal, spinal surgery may have to be repeated. A failed fusion is termed a nonunion or pseudoarthrosis. Spinal instrumentation, although very strong, may even break if nonunion occurs. Needless to say, spine surgeons try to minimize the risk of this happening.

Cigarette Smoking and Failed Fusion

Certain factors have been found to affect the success of spinal fusion. Some of these factors include the patient’s age, underlying medical conditions (e.g. diabetes, osteoporosis), and cigarette smoking. There is growing evidence that cigarette smoking adversely affects fusion. Smoking disrupts the normal function of basic body systems that contribute to bone formation and growth. As mentioned previously, new bone growth is necessary for a fusion to heal.

Research has demonstrated that habitual cigarette smoking leads to the breakdown of the spine to such a degree that fusion is often less successful when compared to similar procedures performed on non-smokers. In a study of patients undergoing anterior cervical fusion (fusion of the neck), it was observed that smokers had an increased rate of nonunion (up to 47%) as compared to non-smokers.1

Another study evaluated tobacco use in patients who underwent lumbar (low back) fusion. The patients who smoked had failed fusions in up to 40% of cases, compared to only 8% among non-smokers.2 Similar findings have been reported in other studies as well.

Post-Operative Infection

Cigarette smoking compromises the immune system and the body’s other defense mechanisms, which can increase the patient’s susceptibility to post-operative infection. A study conducted by Thalgott et al showed that cigarette smoking was a risk factor for infection following spinal fusion.3

Conclusion

Clearly, cigarette smoking is detrimental to spinal fusion. People who are facing fusion or any spinal surgery should make every effort to stop smoking. Quitting the habit beforehand will decrease the associated risks and increase the likelihood of a successful spinal fusion surgery.

Your physician recognizes the importance of smoking cessation and can provide information about available treatment options.

References

1. An HS, Simpson JM, Glover JM, Stephany J. Comparison between allograft plus demineralized bone matrix versus autograft in anterior cervical fusion. A prospective multicenter study. Spine 1995; 20: 2211-16.

2. Brown CW, Orme TJ, Richardson HD. The rate of pseudarthrosis (surgical nonunion) in patients who are smokers and patients who are nonsmokers: a comparison study. Spine 1986; 9: 942-3

3. Thalgott JS, Cotler HB, Sasso RC, LaRocca H, Gardner V. Postoperative infections in spinal implants. Classification and analysis — a multicenter study. Spine 1991: 8: 981-4.
Original Source: Larry Davidson, M.D. Spine Universe, Memphis, TN, USA 07/28/2006

Peripheral Arterial Disease and Smoking

“About 80% of the patients whose legs or extremities I have to amputate are current smokers. If they are not current smokers, then they almost certainly used to smoke.

If patients presenting with PAD have never smoked, I have cause to doubt whether they have the disease at all.” -Mr. Daryll Baker, Consultant vascular surgeon, Royal Free Hospital.

The most common cause of peripheral arterial disease (PAD) is atherosclerosis. In atherosclerosis, fatty deposits (plaques) build up in your artery walls and reduce blood flow.

PAD mimics a condition similar to coronary artery disease and carotid artery disease where fatty deposits build up in the inner linings of the artery walls.

These blockages restrict blood circulation, mainly in arteries leading to the kidneys, stomach, arms, legs, and feet.

Book Cover of Peripheral Arterial DiseaseRobert S. Schwartz, MD states: “Atherosclerosis and PAD is pretty much the same thing. Atherosclerosis is the hardening of the arteries.

It’s the plaque that builds up; it’s the calcium, the fats, the fibrous tissue, the scarring that grows into the arteries and stops the blood from flowing into the legs.”

In the UK, about 2.7 million people age 55 or older, have some degree of peripheral arterial disease and almost 8-12 million people in the United States who have this disease are unaware of having this condition.

PAD is often silent for a very long time before you will notice any symptoms. Some Symptoms of PAD may include:

  1. Foot pain that does not go away when you stop exercising
  2. Cold and numb feet or toes
  3. Leg numbness or weakness
  4. A change in the color of your legs
  5. Decreased leg strength, function, and poor balance
  6. Experiencing discomfort within the muscles of the calves or the thighs, or the buttocks may be indicative of claudication (PAD leg pain occurs in the muscles, not the joints)
  7. Hair loss on your feet and legs
  8. Changes in your nails
  9. Foot pain at rest, which indicates that PAD is getting worse
  10. Foot or toe wounds that will not heal or heal very slowly
  11. Erectile dysfunction
  12. Gangrene

*Symptoms of peripheral vascular disease depend on what artery is affected and how severely the blood flow is reduced.

One of the serious sub effects of peripheral vascular disease is Buerger’s disease (thromboangiitis obliterans). It is characterized by a combination of inflammation and clots in the arteries and veins that obstruct blood flow.

Brandon Carmichael is a young man who has suffered this disease to an extreme, having had his left leg amputated below the knee from smoking.

The risk of peripheral vascular disease is dramatically increased in smokers. When a person stops smoking, regardless of how much he or she may have smoked in the past, their risk of peripheral vascular disease rapidly declines.

In a Health Briefing on Silent Epidemic, Peripheral Arterial Disease article Alan T. Hirsch, MD, Chair, P.A.D. Coalition states, “Peripheral arterial disease is the most dangerous disease that most Americans have never heard of”.

The same article continues with the following warning: “People with peripheral arterial disease – P.A.D. – have up to a six-fold increase in cardiovascular death. Without early detection and proper treatment, one in four people with P.A.D. will suffer a heart attack, stroke, amputation or die within the next five years.”

If you add a bad diet and a sedentary lifestyle into this equation, you probably have a prescription to die much younger. How many smokers with Peripheral Arterial Disease have died of a heart attack or stroke where the connection to smoking as a risk factor fell silent?

An absence of a pulse in your legs or arms should immediately alert your health care provider to seek further testing for Peripheral Arterial Disease. eMedicineHealth has an excellent article on Exams and Tests regarding Peripheral Arterial Disease. It is very important that you consult with your health care provider if you believe that you are at risk for this disease.

Are you a smoker? If you are a smoker the most important thing you can do for your health is to educate yourself about smoking-related diseases. If you are an ex-smoker, you also need to stay abreast of learning about smoking-related diseases. Knowledge is power!


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