Tobacco is a plant grown for its leaves, which are smoked, chewed, or sniffed for a variety of effects. It is considered an addictive substance because it contains the chemical nicotine.

In addition to nicotine, tobacco contains over 19 known cancer-causing chemicals (most are collectively known as "tar") and more than 4,000 other chemicals. These include acetone, ammonia, carbon monoxide, cyanide, methane, propane, and butane.

Over 38 million people in the United States have successfully quit smoking.

Yet there are still around 50 million Americans who smoke. The majority say they would like to quit.

And, while the number of cigarette smokers in the United States has dropped over recent years, the number of *smokeless tobacco* users has steadily risen.

This trend is likely related to the false belief that smokeless tobacco is safe. It is NOT. Smokeless tobacco carries many of the same health risks as cigarettes. Some people who want to stop smoking, but who still crave the nicotine, turn to smokeless tobacco wrongly thinking that they are doing something good for themselves.

The effects of nicotine

- Nicotine acts as both a stimulant and depressant on your body. It increases your bowel activity, saliva, and bronchial secretions.

It stimulates the nervous system and may cause tremors in the inexperienced user, or even convulsions with high doses.

- After stimulation, there's a phase that depresses the muscles in your airways. As a euphoric agent, nicotine causes relaxation from stressful situations.

- On average, tobacco increases your heart rate 10 to 20 beats per minute, and it increases your blood pressure reading by 5 to 10 mmHg (because it constricts the blood vessels .

- Nicotine may also cause sweating, nausea, and diarrhea. Nicotine elevates the blood level of glucose (blood sugar) and increases insulin production.

Nicotine also tends to enhance platelet aggregation, which may lead to blood clots .

- Nicotine temporarily stimulates memory and alertness. People who use tobacco frequently depend on it to help them accomplish certain tasks at specific levels of performance. Nicotine also tends to be an appetite suppressant .

(For this reason, fear of weight gain also influences the willingness of some people to stop smoking.)

Finally, tobacco is highly addictive. It is considered mood and behaviour altering. Tobacco is believed to have an addictive potential comparable to alcohol, cocaine, and morphine .

Health risks

There are many reasons to quit using tobacco. Knowing the serious health risks may help motivate you to quit. When used over a long period, tobacco and related chemicals such as tar and nicotine can increase your risk of:

- Blood clots, which may lead to aneurysms and strokes - Cancer (especially in the lung, mouth, larynx, esophagus, bladder, kidney , pancreas - Coronary artery disease, including angina and heart attacks

- Decreased ability to taste and smell

- Delayed wound healing

- High blood pressure

- Lung problems such as emphysema and chronic bronchitis

- Pregnancy-related problems, including miscarriage, premature labor, low birth weight and risk for sudden infant death syndrome

- Tooth and gum diseases

You have the same risks if you use smokeless tobacco (chewing tobacco, snuff, etc.) for a long time. In addition, smokeless tobacco users have a 50 times greater risk for mouth cancer than those who do not use such products.

Secondhand smoke

Those who are regularly around the smoke of others (secondhand smoke) have a higher risk of:

- Coronary artery disease

- Lung cancer - Sudden and severe reactions, including those involving the eye, nose, throat, and lower respiratory tract.

Infants and children that are exposed regularly to secondhand smoke are at risk of:

Asthma - Infections, including virus-caused upper respiratory infections, ear infections and pneumonia - Lungs that do not work as well (poor lung function)

- Sudden infant death syndrome (SIDS)

Time to quit

There are a lot of ways to quit smoking and many resources to help you.

Family members, friends, and coworkers may be supportive or encouraging, but the desire and commitment to quit must be your own.

Most people who have been able to successfully quit smoking made at least one unsuccessful attempt in the past. Try not to view past attempts to quit as failures, but rather as learning experiences.

Feel ready to quit? Here are some tips:

- List the reasons you want to quit. Include both short-and long-term benefits.

- Ask your health care provider for help. Find out whether prescription medications might help. Also ask about nicotine patches, gum, and sprays.

- Ask your family, friends, and coworkers for support.

- Set a quit date, and get rid of all of your cigarettes by that date.

- Quit completely - cold turkey.

- Get more exercise. It relieves the urge to smoke.

- Learn self-hypnosis from a qualified practitioner. This helps some people.

- Make a plan about what you will do, instead of smoking, when stressed or other times you have the urge for tobacco. Be as specific as possible.

- Avoid smoke-filled settings and situations in which you are more likely to smoke. Like any addiction, quitting tobacco is difficult, particularly if you are acting alone. If you join smoking cessation programs, you have a much better chance of success. Such programs are offered by hospitals, health departments, community centers, and work sites. The best quit-smoking programs combine multiple strategies, including peer support and ways to overcome potential relapse situations. Counselling by telephone can be a very helpful reinforcement, even as effective as face-to-face counselling.

Child's sleep linked to adulthood obesity risk

Consistently getting a good night's sleep may help protect children from becoming obese as adults, a study published Monday suggests.

Researchers found that among more than 1,000 people followed from birth to age 32, those who got too little sleep as children were more likely than their well-rested counterparts to become obese adults.

Even with a range of other factors considered - like childhood weight and TV habits, and adulthood exercise levels - there remained a link between sleep deprivation during childhood and obesity risk later in life.

All of this supports the idea that early sleep habits have a direct effect on weight in the long term, according to Dr. Robert John Hancox, the study's senior author.

"Although we cannot prove that this is a cause-and-effect relationship," he told Reuters Health, "this study provides strong evidence that it probably is."

Hancox and his colleagues at the University of Otago in Dunedin, New Zealand, report the findings in the journal Pediatrics.

A number of studies have found that sleep-deprived adults and children are at greater risk of being overweight. However, this is the first study to show a long-term relationship between sleep and obesity risk, Hancox said.

The study involved 1,037 men and women who had been followed since their birth, between 1972 and 1973, up to the age of 32. When the participants were 5, 7, 9 and 11 years old, their parents reported on their usual bed time and wake-up time.

In general, Hancox and his colleagues found, as childhood sleep time declined, adulthood body mass index, or BMI, climbed.

Adults who had been "short sleepers" as children - averaging fewer than 11 hours in bed each night - generally had a higher BMI than those who'd gotten more sleep as kids.

"Importantly, this is not because children who were short sleepers grew up to be short sleepers as adults," Hancox pointed out. "In other words, inadequate sleep in childhood appears to have long-lasting consequences." The findings, according to the researchers, suggest that weight control may stand as another reason for children to get a good night's sleep. Experts generally recommend that children between the ages of 5 and 12 sleep for about 11 hours each night, while teenagers should get 8.5 to 9.5 hours. It's thought that children today are getting less sleep than the generations before them did, Hancox noted.

That trend, he added, could be helping to feed the rise in obesity. No one knows for certain why lack of sleep is linked to heavier weight. One theory, based on research in the sleep lab, is that sleep deprivation alters the normal balance of appetite-stimulating and appetite-suppressing hormones. Sleepy children may also be too tired for physical activity during the day.

Reuters Health

Methanol (Methyl Alcohol) poisoning

by D. P. Atukorale

Methanol which is also called wood spirit is widely used in the production of formaldehyde, and is also used to denature alcohol. It is used in antifreeze solutions, paints, duplicating, fluids, paint removers and varnishes and as a solvent.

From time to time we hear of deaths and blindness in those who survive after consuming kasippu containing methanol in significant concentrations.

A few days ago the news media reported a number of deaths and permanent blindness in some of those who survived after consuming kasippu containing methanol, ingestion of as little as 10ml of methanol can cause permanent blindness and 30ml of methanol is potentially fatal in majority of those who consume methanol.

Toxicity also can occur due to inhalation or absorption of methanol from the skin.

Methylated spirits consist of 5 percent methanol and 95 percent ethanol (ethyl alcohol) and contrary to popular opinion toxicity of methylated spirit is mainly due to the presence of ethanol.

In humans, methanol is metabolised by an enzyme called alcohol dehydrogenase and catalase enzyme systems, to formaldehyde and formic acid and the patients get acidosis due to concentration of formate. Depression of liver enzyme systems inhibit glucose production by the liver (gluconeogensis) and lactate so produced make the acidosis worse.

It is not certain whether the blindness is due to local formation of formaldehyde in the retina of the eye or due to damage to the optic nerve of the eye as a result of enzymes activity by the formate. Methanol also interferes with the utilisation of vitamin A in the eye.

The patients who come to the hospital may present to the doctor with mild and transient inebriation and drowsiness when methanol is ingested alone.

After a latent period of 8 to 36 hrs nausea, vomiting, abdominal pain, headache, dizziness and coma supervene.

Blurred vision and diminished visual activity may occur and the pupils of the eyes get dilated in people who get permanent blindness. In severe cases metabolic acidosis accompanied by high blood sugar occurs.

A blood methanol level greater than 500mg/L confirm serious methanol poisoning.

If the patient is brought to the hospital in the first two hours of the poisoning, doctors give gastric lavage. If the patient arrives at the hospital after two hours with acidosis these patients' acidosis can be corrected by giving bicarbonate. Correction of the blood pressure is important and it is advisable to keep the patients in the Intensive Care Unit (I.C.U.).

Early cases are treated with alcohol (ethyl alcohol or ethanol), but, giving alcohol is useless if the patient arrives late. If the patient comes after about four hours it is not a wise move to give ethanol as, acidosis may get worse.

If the patient comes in the first two hours, physicians usually give about 50gm of ethanol in the form of arrack or whisky or gin and this should be followed by an infusion of 10 to 12gm of ethanol.

As stated earlier, ideally all patients with methanol poisoning should be managed in an intensive care unit where serum ethanol and methanol levels can be estimated from time to time.

In patients who have ingested large amounts of methanol dialysis (haemodialysis or peritoneal dialysis) should be done, two to three hourly so that toxicity to optic nerve can be prevented.

I reliably understand that the Excise Department is planning to introduce new regulations to dilute the methanol before issue to the market as a safeguard against it being used for illicit manufacture of kasippu.

Lining draws the first line

by Dr. Viith Vidyavibushana

Consultant Gynaecologist, Castle Street Hospital for Women

Under the influence of the female hormone oestrogen (produced by the cells surrounding the growing egg in the ovary) the lining of the womb starts to grow from day one of the menstrual cycle. This growth occurs to optimize the environment for a future pregnancy to burrow into the lining of the womb. Once the egg is released,(usually on day 14 of a 28 day menstrual cycle) the ovary starts producing another female hormone called Progesterone. The effect of this hormone(a hormone is a chemical substance found in blood) makes the lining of the womb more favourable for the pregnancy to settle in.

The ovary can produce progesterone only for a short period, and on about 26th day of the menstrual cycle the progesterone level goes down. Therefore the lining of the womb breaks down due to low progesterone level and menstruation starts on day 28. Majority of those who have regular menstrual cycles release an egg regularly. If an egg is not released in a menstrual cycle, the lining of the womb will only have the effect of the hormone oestrogen. This will give rise to thickening of the lining and irregular menstrual cycles.

The fertile period is the period during which one can get conceived following unprotected sex. It is important for couples to have an idea about this period especially when planning a pregnancy. As the lifespan of the ovum (egg) is about 24-48 hours, egg should meet a sperm before it dies so that a pregnancy can occur.

Once the egg is released from the ovary it is caught up by the outer end of the Fallopian tube, and then the egg travels through the tube to the outer one third of the fallopian tube where it meets the sperm (called Fertilization). As the lifespan of the egg is limited, sperms have to be there when the egg reaches the fallopian tube for fertilization to occur.

Although the sperms die within hours after ejaculation, they can survive up to a maximum period of seven days once they get in to the fallopian tubes.

However, to get the maximum chance to get conceived, it is best to have sex during 'the fertile period'. Usually this period starts two days before ovulation and two days after ovulation. Eg - If a women is having a 28 day menstrual cycle the fertile period is from 12th to 16th day if ovulation occurs on day 14.

It is very important to know that first day of the menstrual cycle is the first day or the onset of menstrual bleeding. Even if one has been having very regular menstrual cycles, it is difficult to predict the exact date of ovulation. That is one of the reasons to have a fertile 'period' rather than a fertile day.

According to medical evidence it has been shown that awaiting 'fertile period' to plan a pregnancy can give rise to undue stress. Having sex twice or three times a week will increase the chances of getting conceived without any stress rather than waiting for the fertile period.

*Can we avoid this fertile period as a method of natural contraception?* NO.

We know that the sperm can live up to a maximum of seven days in side the Fallopian tubes. Therefore it is not a reliable method as a means of contraception (family planning) since a sperm which entered seven days before ovulation can fertilize the egg. Also ovulation can get delayed in some menstrual cycles during the reproductive life in any woman, even if one has been having very regular cycles. Considering above facts it is necessary for someone to know the duration of the shortest and the longest cycle during a period of six months to one year to use the 'natural method of contraception'.