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Does good hygiene beget bad health?

Posted by iKnowHOW on October 30, 2006

Genetically tinkered parasitic worms actually have the potential to lower the incidence of autoimmune diseases, writes P.K. Sumodan

Catch-22: Unhygienic living conditions play an important role in strengthening immunity

It all started with a group of genetically-modified mice with a predisposition to Type 1 diabetes that Professor Anne Cooke of Cambridge University, UK, and her colleagues were researching on. Once, some of the mice, while being transported from London, caught bacterial and parasitic infections. This led to an unexpected result — only 50 per cent of the rodents developed diabetes instead of the expected 80 per cent.

Prof. Cooke immediately sensed a correlation between the two incidents. To test the hypothesis, she and her team infected the genetically modified mice with a parasitic worm called schistosome, which causes schistosomiasis (snail fever), a disease found in parts of Africa, Asia and South America. The scientists found the infection reduced the incidence of diabetes.

In fact, when the mice were infected early in life, none of them went on to develop Type 1 diabetes. Further research showed it was some component of the egg rather than the later stages of the parasite’s development that protected the mice from diabetes.

However, in European countries, where schistosomiasis is non-existent, there has been an increase in the occurrence of autoimmune diseases such as Type 1 diabetes, rheumatoid arthritis, Crohn’s disease (also called regional enteritis characterised by diarrhoea, cramps and loss of appetite) and so on.

Autoimmunity is an abnormal function of our immune system, where antibodies are produced against one’s own cells. In Type 1 diabetes, for instance, pancreatic cells are destroyed by the immune system so that the production of insulin is curtailed.

Interestingly, even though schistosomiasis is absent in many Asian countries including India, these nations do not have a very high incidence of autoimmune diseases. The reason, experts say, could be the prevalence of intestinal bacteria and parasitic worms such as hookworm, pinworm, filarial worm and round worm in these countries. According to Prof. B.S. Ramakrishna of the department of gastrointestinal sciences, Christian Medical College, Vellore, intestinal infection with Helecobacter pylori — a bacteria causing certain ulcers — could be the reason for the low incidence of autoimmune diseases in India.

Hygiene hypothesis

In an article titled “Parasitic worms and inflammatory diseases” in the journal Parasite Immunology (October 2006), Professor Cooke and her colleagues discuss the emerging evidences favouring the “Hygiene hypothesis”, which states that better hygiene and lack of parasites are related to the high incidence of autoimmune diseases.

The researchers say that early human civilisations were exposed to a host of pathogens because of unhygienic living conditions, unclean drinking water, improper sanitation and so on. In due course, the immune system adapted itself to these pathogens and the accompanying parasites and bacteria. In other words, parasites and microbes have played an important part in strengthening one’s immunity.

Most autoimmune diseases are genetic disorders. How, then, does aschistosomal infection help? Studies conducted on twins having the same genes but living in different environments showed that environment played a key role in the expression of the genes. It was found that in hygienic environments, the immunological responses triggered by the immune system were diverted to a different target. In the event of aschistosomal attack, the immune system, instead of targeting the pancreatic cells (that lead to Type 1 diabetes), attacks the infection. This mechanism explains the role of infections in reducing autoimmune disorders.

Worms for health

So what would we prefer: autoimmune diseases or diseases caused by parasitic worms? Since autoimmune diseases are genetic disorders, curing them completely requires gene therapy, a costly and less successful process. On the other hand, parasitic worms can be effectively managed with cheap medication.

However, unhygienic conditions could lead to more serious problems such as cholera. A better option would be to take cues from the “Hygiene hypothesis” and develop better strategies to combat autoimmune diseases.

We may use genetically modified worms, which can elicit the required immune responses from our immune system without triggering any harmful effects. A better option would be to develop a drug based on the chemicals present in the worms that stimulate immune response. It will be interesting to see a reversal in worm related practice, a change from de-worming to artificial worming!

(The author is a lecturer of zoology at a Kerala government college.)

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Beyond condoms

Posted by iKnowHOW on October 30, 2006

Forty years after the introduction of the female birth control pill, researchers are still optimistic about the feasibility of a male hormonal contraceptive. Regina Nuzzo reports

Family planning: Millions of men would like to have options beyond condoms or vasectomy

Four offsprings are plenty for 37-year-old Glen Magdaleno of Los Angeles. “I love my kids, but I just can’t have any more and still be a good parent,” he says.

Magdaleno, like millions of other men, would like to have options beyond condoms, vasectomy or withdrawal. To those ends, he recently volunteered at Harbor-UCLA Medical Center to test one of several male birth control drugs being developed around the world.

Every day during the month-long study, Magdaleno smeared hormone-laced gel over his upper body. The drug was designed to penetrate his skin, enter his bloodstream and trick his body into shutting down testicular functioning.

Drugs now in development use hormonal methods similar to those used in many female contraceptives. Small studies have found their delivery — a combination of implants, injections and gels — to be generally safe, reversible and effective in lowering sperm counts.

Male hormonal methods work by adding testosterone or other male hormones to the bloodstream. The brain senses these extra hormones and, to keep the reproductive system in balance, sends chemical signals to shut down the testes. This halts production of sperm cells. It also blocks normal production of testosterone — responsible for male characteristics, from facial hair to sex drive — but the added male hormones serve to take up the slack.

Researchers have found they can boost the sperm-suppressing effects of the added male hormones by also administering progestin, a type of hormone used in female birth control pills and found naturally in small amounts in men. The progestin reinforces the chemical messages that shut down the testes.

Sperm production can then be suppressed with even less testosterone, which helps avoid some of the hormone’s side effects, such as its tendency to decrease levels of heart-healthy HDL cholesterol and the possibility of contributing to prostate cancer.

The need for high doses of testosterone makes a male birth control pill tough to formulate, says Dr Christina Wang of the LA Biomedical Research Institute at Harbor-UCLA Medical Center. Drops or spikes in hormonal levels can trigger sperm production, so a steady delivery method is crucial. Unlike estrogen, however, testosterone doesn’t work well in a daily pill. The hormone tends to immediately break down in the liver.

To bypass this route, researchers are instead experimenting with ways to administer hormones directly into the bloodstream — including a combination of slow-release implants, long-lasting injections or daily gels.

Researchers in China are wrapping up the largest of these trials, a two-year efficacy study of approximately 1,000 volunteers, says Kirsten Vogelsong, a scientist at the World Health Organization. Preliminary results suggest that most men remained infertile during the testosterone injection regimen.

A small study in Seattle suggests testosterone might also be effective when applied onto the skin. Thirty-eight volunteers used a daily testosterone gel in addition to slow-release progestin implants. In 90 per cent of the men, sperm counts dropped to infertile levels within six months. Most of these levels returned to normal soon after the trial ended.

For men who dislike daily routines, once-a-year surgery might be more attractive. The Population Council, a non-profit international research organisation in New York, is working on a slow-release implant of a powerful testosterone derivative, says Dr Reginé Sitruk-Ware, executive director of product research and development. This compound — administered through four small plastic rods that release hormones for up to a year — could spare the prostate from long-term side effects, she says. In initial tests in Europe, South America and Los Angeles over the last five years, the drug blocked sperm production completely in 72 out of 87 volunteers. Researchers are now tinkering with the rubber material used in the implant and hope to test a new single-rod implant in clinical trials within a couple of years.

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Preventing pregnancy

Posted by iKnowHOW on October 30, 2006

Ovulation occurs in women on the fourteenth day before the onset of the next period. This is the period of maximum fertility
   
The “safe period” method is at times more successful in planning pregnancy than preventing it, and (bottom) an IUD

This column receives many queries about contraception, even if the last article had nothing to do with sex. Is this because, despite our exploding population, our push for family planning and our desire to propagate the one-child norm, sex education is not yet an integral part of the school curriculum?

Our teenagers receive inaccurate, incorrect and inadequate information about sex from folklore, peers, pornography and the Internet.

Contraception is not really a licentious 20th century notion. Nobody ever wanted to reproduce every time they had sex. Egyptian women inserted vaginal tablets made from mildly acidic substances, the French used a hair from a horse’s mane and sometimes honey or oil was poured into the vagina soon after intercourse to prevent conception. The Chinese used the first female condoms — a cervical blocking cap made of oiled paper. The first male condoms were made of animal intestine and were used in the 17th century.

These methods were unpleasant and inefficient, so the science of contraception evolved to produce the more reliable methods that we have today.

Women can prevent pregnancy by abstinence (not having sex at all). Timed intercourse is more popular than abstinence and is considered “natural”. The “safe period” when unprotected intercourse is least likely to result in a pregnancy is carefully calculated. Ovulation (release of the egg) occurs in women on the fourteenth day before the onset of the next period and that is the period of maximum fertility. Avoiding intercourse for five days before and after this date decreases the chances of an unwanted pregnancy. This method can be combined with “coitus interruptus,” when ejaculation is controlled and takes place outside the vagina.

Women do not function like machines. Menstrual cycles can suddenly lengthen or shorten, making this an unreliable method. Its efficiency can be increased by watching the consistency of the cervical mucous. This changes from clear and transparent to sticky and opaque in the safe period. The body temperature also rises by 0.5 degree C during ovulation and this can be measured daily with a thermometer. All these methods require an understanding and compliant male partner, and are more successful in planning pregnancy than preventing it.

Oral contraceptive pills (OCPs) taken by women are safe, popular and reliable provided they are taken as prescribed, at the same time every day. They are combinations of synthetic estrogens and progesterones and are taken for 21 days at a stretch. Then there is a “pillfree” interval of seven days, during which menstruation occurs. Some companies provide a 28-day pack, in which the last seven tablets are placebos. If a pill is forgotten, two should be taken the next day. If there have been two or more pill-free days, contraception is not assured. The actual formulation of the various hormones in the pills marketed vary. The pill best suited to that particular individual can be prescribed. Pills are contra-indicated in those with complicated diabetes, thrombo-embolism, sickle cell disease, cancer of any reproductive organ and undiagnosed vaginal bleeding.

Progesterone-only pills are also available and can be used in women in whom estrogens are contra-indicated. They are taken continuously with no pill-free interval.

India has also developed a contraceptive tablet called centchroman which belongs to the SERM (Selective Estrogen Receptor Molecule) group of medications.

OCPs are very safe and can be taken for years. They do not increase the risk of cancer or decrease the chances of a subsequent pregnancy.

For women who cannot remember to take their tablets, long acting progesterone injections like medroxyprogesterone acetate or norethisterone acetate can be given every 12 and 8 weeks, respectively. Alternatively, an IUD (intrauterine device) can be inserted and left in situ to prevent pregnancy for around three years.

Condoms, both male and female, if properly used from the beginning to the end of intercourse protect against both pregnancy and STD. Their efficacy is increased if they are combined with a spermicidal cream.

Accidents can occur and people may have sex first and remember contraception afterwards. The government has licensed the use of “emergency contraceptive morning after pills”. They are effective if taken within 72 hours.

Abortion is legal in India and medical methods with mifepristone and misoprost can be used up to 49 days.

If the pregnancy is more advanced, surgical methods like suction or dilatation curettage are needed. Permanent contraception can be achieved by surgical sterilisation, a tubectomy in women and vasectomy in men.

Pregnancy can occur if contraception is not used during lactation, with irregular cycles or even if there has been prompt douching.

Responsibility for safe sex rests with both partners. However, unfortunately, it is the women who display the obvious outward results of an unprotected sexual encounter. Would men be more careful if they were the ones becoming pregnant?

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