Chitosan can provide protection against typhoid. Researchers fromthe Government College of Pharmacy, Tamil Nadu, have found that chitosan - a natural polymer found in the waste of the processed seafood industry - can provide protection against typhoid. Chitosan is derived from chitin, present in the exoskeleton of crustaceans such as crabs, lobsters and shrimps.

To study the anti-microbial potential of the polymer, the researchers placed paper cups containing chitosan dissolved in citric acid in plates of nutrient containing colonies of different typhoid-causing bacterial strains. After the plates were incubated for 24 hours, they were analysed for microbial growth inhibition. It was found that chitosan has an exceptionally good anti- bacterial activity.

As a next step, the researchers compared the anti-microbial activity of chitosan with that of standard antibiotics. Its efficacy against several strains of the typhoid-causing Salmonella enterica, which are resistant to commonly used antibiotics such as chloramphenicol and ciprofloxacin, was found to be relatively high. The researchers hope the molecule will be used by the pharmaceutical industry to overcome the problem of resistance faced by many drugs.

December 15, 2004 Down to Earth

Stem cells

Stem cells are cells that can replicate themselves and also generate specialized cells as they multiply. Stem cells could be used to generate replacement cells and tissues to treat many diseases and conditions including Parkinson's disease, leukaemia, stroke, diabetes, spinal cord injury and skin conditions, including burns. Damaged organs or tissues would be colonized with sufficient normal cells with an appropriate scaffold for their reconstruction.

Stem cells occur at all stages of development from embryo to adult but their versatility and abundance gradually decrease with age. While embryonic stem cells may be able to produce any of the 200 different types of specialized cells that make up the human body, adult stem cells appear to be capable of producing only one or a limited number of types of cell. Recently some have argued that adult stem cells have proved sufficiently versatile and therefore there is no need to derive stem cells from very early human embryos. We believe the scientific findings that have been reported so far do not support this conclusion. Therefore research on both adult and embryonic stem cells is vital for a proper evaluation of the prospects of stem cell therapy for the treatment of serious disease and injury.

October 25, 2005 Current Science

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Do not reuse mineral water bottles !

Some of you may be habit of using and re-using your disposable mineral water bottles (Nestle, Bisleri, Aquafina, Kinley, Evian). Not a good idea.

In Dubai, a 12-year-old girl died. She was using a SAFA mineral water bottle for a protracted period of 16 months. The cause: the plastic (polyethylene terephthalate or PET) used in these bottles contains a potentially carcinogenic (cancer-causing) element -diethylhydroxylamine or DEHA.

The bottles are safe for one-time use only. If you must keep them longer, it should be for no more than a few days, a maximum period of a week. They must be kept away from heat as well. Repeated washing and rinsing causes the plastic to break down and the carcinogens can leak into the water you are drinking. It is then better to invest in water bottles meant for multiple uses. After all, prevention is better than cure.

May 31, 2004 Down to Earth

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Why do bags form below our eyes ?

Dark circles and bags under the eye occur for several reasons: the skin there is much thinner than it is elsewhere on the body and becomes looser as we age. This very thin skin also sits on top of underlying purple muscle and blood vessels and therefore appears darker. In addition, some people have hereditary pigmentation in this area. As we age, fat comes out of the space enclosed by the eye socket, called the orbit, and forms a puffy area under the eye. This fatty tissue can fill with water, making the hollow appear even deeper. The condition becomes even more noticeable when water is retained in the fat pad, which can occur for a variety of reasons, including eating too much salt, lying flat in bed, not getting enough sleep, allergies and monthly hormonal changes.

Treating the hollow space under the eye is straightforward and can be done by injecting a filler such as Restylane. Immediately after this procedure, the so- called tear trough is softened, and any visible pigmentation becomes noticeably lightened. A carbon dioxide (CO₂) laser also can be used to resurface the skin, which tightens and thickens it as well as lightening the coloring. For hereditary pigmentation, CO₂ laser resurfacing and bleaching creams are sometimes helpful. As an option, a surgeon can perform blepharoplasty to fix the fat pad under the eye.

To reduce the puffiness and darkness of under-eye circles include avoiding salt, using cold compresses on the eyes, getting enough sleep, treating allergies, as well as sleeping with your noggin higher by resting it on two pillows or raising the head of the bed.

Ashwangandha

The ashwagandha root is notable for asteroid called withanolide, which is anti-inflammatory. It also contains alkaloids, particularly withasomnine, that are responsible for the root's sedative qualities.

Aswagandha has traditionally been prescribed as a tonic. This use was supported by a paper published in the Journal of Ethnopharmacology in 2000, which described how the plant helps the body to cope with and adapt to stressful situations. It also lowers blood pressure, slows the heart rate and boosts the immune system. In Indian medicine ashwagandha is commonly prescribed to help convalescing patients to overcome fatigue. The plant is also used to treat anxiety and nervous problems and in large doses can induce sleep.

Research performed in America in 1991 found that ashwagandha contains components that act in the same way as the main inhibitory neurotransmitter in the central nervous system. It is this that is likely to account for its sedative and sleepinducing qualities.

Painful rheumatic joints respond to its anti-inflammatory properties and its high iron content makes it useful in the treatment of anaemia.

2004, Reader's Digest

Nature's Medicines

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This is a good bioenhancer Drumstick molecule increases absorption of drugs

Scientists from Lucknow-based Central Institute of Medicinal and Aromatic Plants (CIMAP) have isolated a molecule from pods of drumstick (Moringa oleifera) that enhances the absorption of drugs and nutrients by humans. Almost all parts of the plant have medicinal properties. For instance, the paste of the leaves can help fight cancer.

The newly discovered molecule, called niaziridin, improves the absorption of drugs, particularly antibiotics such as rifampicin, tetracycline and ampicillin, through the gastro-intestinal membrane. Similarly, it can augment the uptake of nutrients like vitamin B12. This makes niaziridin a good bioenhancer, the researchers state in a patent application filed with the US Patent and Trademark Office on October 7, 2004. Bioenhancers are molecules that do not posses drug activity of their own but promote the uptake of drugs in combination therapy.

Niaziridin would particularly prove useful in tuberculosis (TB) therapy. Patients normally have to undergo the therapy for six to eight months. The main anti-TB drugs such as rifampicin and isoniazid exhibit significant toxicity in the mammalian systems. Gastric irritation and hepatitis are some of the major side-effects of rifampicin, whereas nausea, jaundice and lack of appetite are associated with isoniazid. If naiziridin is used in combination with these drugs, the side-effects can be minimized. Moreover, the cost of treatment will also reduce.

December 15, 2004 Down to Earth

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Polymeal saves heart patients

If you enjoy good food and don't like the idea of taking pills to reduce the risks of heart attack or stroke, it could be time to try the polymeal. 

Foods ranging from wine to fish and fruits and vegetables have been shown to reduce the risk of cardiovascular disease, so Dr. Oscar Franco, a public health expert at the Erasmus Medical center in the Netherlands, decided to combine them in one meal.

If people over 50 years old consumed roughly the daily equivalent of the polymeal, the researchers calculated, they could slash the odds of suffering from heart disease.

He and his team searched scientific literature to find foods that have a proven protective effect against cardiovascular disease and then used a mathematical model to determine how much the combined effects of the individual ingredients would reduce the risk of the illness. The results are reported in the British Medical Journal. The polymeal consist of wine, fish, dark chocolate, fruit and vegetables, garlic and almonds. The ingredients should be taken daily, apart from fish which could be eaten about four times a week as part of a balanced diet.

Wine and chocolate must be consumed in moderation. The scientists said the result of eating the polymeal would be most dramatic for men, whom they estimated would live 6.6 years longer in total than their counterparts not eating the meal. They would also delay the onset of heart disease by 9 years. Women would gain nearly 5 years and keep heart disease at bay for about 8 years. Polymeals, combined with exercise and non-smoking, are the ingredients for a healthy lifestyle to prevent heart disease.

February 2005, Health Action

Rubber from mushroom

Japanese researchers say they have produced rubber from a substance extracted from a wild mushroom variety commonly found in the country. Researchers at Gunma University have not only produced rubber from the chichitake mushroom, the end product also has the advantage of not containing a protein that can cause allergies among humans. At present, it takes more than 10 kg of mushroom to make only one kg of the rubber. The researchers are now refining their process to overcome this major drawback.

December 31, 2004 Down to Earth

Digital album

In near future, images can be stored in liquid crystals. When S Krishna Prasad and co-workers at the Centre for Light Crystal Research in Bangalore shown a light on a class of liquid crystals, it induced the crystal molecules to change shape on a quick time- scale. This finding suggests that the system is a potential candidate for storage of images or other optical data.

Phase transitions of shape, induced by temperature, are common in nature; for example ice is transformed to water when it is heated. In recent years, however, it has been found that light can mimic the role played by temperature in bringing about a phase transition. This occurs in certain materials with properties that are in between that of a solid and liquid, namely liquid crystals.

Prasad and his colleagues discovered that the key to such phase transitions in these materials (like azobenzene) is the change in shape driven by light. In its ground state, the azobenzene molecule, for instance, exists in an arrangement known as trans conformation. But when it is irradiated with light of suitable wavelength (365 nanometer), it undergoes a conformational change to the cis state.

Along with this conformational transformation, the molecule changes shape - in the trans state the molecule has a rod-like shape, but in the cis configuration it is bent like a boomerang. The reverse transformation can be brought about by illuminating the molecule with visible light, although it can also occur spontaneously in the dark by a process known as thermal back relaxation.

What makes this shape change useful is that the rod-like shape supports liquid crystallinity, whereas the bent shape destabilises the liquid-crystal phase. "The change from the trans to the cis form can induce an isothermal transition from the liquid-crystal phase to a liquid phase," says Prasad, adding: "The concomitant change in the related optical properties can be exploited to create a high- resolution, light-driven image storing system."

Furthermore, the changes can be tailor-made to have extremely high long-term stability; holograms (photographic patterns having three dimensions) stored in this way hardly degrade.

Prasad and colleagues summarise various aspects of their investigations by stating that photo-induced phase transition can take place on an extremely quick time-scale of less than a microsecond - a millionth of a second. "Our observations are very significant from the point of view of storing optical images. Moreover, the time-scale of transition can be further improved by embedding the material in a polymer matrix," concludes Prasad.

October 31, 2004 Down to Earth

Shampoos could harm unborn kid

Everyday exposure to a chemical found in many shampoos and hand lotions and widely used in industry could be harmful, a US study found. Called methylisothiazolinone (MIT), it inhibited the development of certain neuron structures that are essential for transmitting signals between cells in the body.

The researchers, from the University of Pittsburg, said MIT restricted the growth of these structures in immature rat nerve cells and many have potentially damaging consequence to a developing nervous system. "There is a potential that everyday exposure to chemical could also be harmful to humans," researcher Elias Aizenman said.

January 2005, Health Action

Hope for glaucoma patients

There is some hope for sufferers of glaucoma and spinal cord injuries as scientists at Schepens Eye Research Institute, have regenerated a damaged optic nerve from the eye to the brain. 

This achievement, which occurred in laboratory mice, holds great promise for victims of diseases that destroy the optic nerve, and for sufferers of central nervous system injuries.

"For us, this is a dream becoming reality." Says Dr Dong Feng Chen, lead author of the study, assistant scientist at Schepens Eye Research Institute and an assistant professor of ophthalmology at Harvard Medical School.

"This is the closest science has come to regenerating so many nerve fibers over a long distance to reach their targets and to repair a nerve previously considered irreparably damaged," he added.

March 2, 2005 The Hitavada

More than just beautiful :

Hibiscus flower extract may have the same health benefits as red wine and tea, according to new research by scientists in Taiwan. Hibiscus contains antioxidants that help control cholesterol levels and reduce heart diseases, says Chau-Jong Wang and his team at Chung Shan Medical University. The scientists have found that the antioxidant properties of flavonoids, polyphenolic compounds and anthocyanins contained in the flower can prevent the oxidation of low-density lipoproteins, which are associated with heart diseases.

October 15, 2004 Down to Earth

Food That Kills

US food agency finds acrylamide in many foodstuffs. Acrylamide, a carcinogen, has been found in many foodstuffs available in the US markets. The toxic substance is formed in starchy foods when they are fried or roasted at high temperatures.

No one suspected it was so pervasive in food until 2002, when scientists of Sweden-based Stockholm University found that French fries sold at Swedish franchises of McDonald's and Burger King contained acrylamide about 100 times more than the World Health Organization's limit for water.

Since then a few countries have conducted tests to gauge acrylamide levels in foodstuffs. During its latest assessment, the US Food and Drug Administration analysed 750 different products. It found no acrylamide in processed cheese, milk and ice cream. But relatively high levels were found in arrowroot cookies, teething biscuits and sweet potatoes. Other childhood favourites such as peanut butter and chocolate chip cookies were also contaminated.

May 15, 2004 Down to Earth

Saffron

Saffron contains a bitter substance called picrocrocin, which stimulates the appetite and aids digestion. The plant's essential oil is rich in safranal, a compound that gives saffron its characteristic aroma, and which could be responsible for the plant's sedative effect. The stigmas contain yellow and red carotenoid pigments-crocin and gentiobiose-that have antioxidant properties.

Saffron has been used as a kitchen herb for centuries, both for its bright orange-yellow colour and for its strong, intense flavour and aroma. The ancient Greeks, Egyptians and Romans valued saffron for its aphrodisiac properties. However, the high cost of this spice means that it is rarely used as a natural medicine. Saffron was traditionally used to treat teething pain in infants. It is thought to regulate menstruation, and aid conception; it is also reputed to remedy colic and lower blood pressure. Saffron is prescribed for nervousness as it is believed to be a sedative. This attribute has not yet been confirmed experimentally, but research in Iran, in 2002, found extracts of saffron to be both anti-inflammatory and analgesic.

Researchers have been looking at the cancer-fighting antioxidant action of saffron. In 1996 Spanish scientists found that saffron inhibited the growth of human tumour cells, a property that they attributed to the carotenoid, crocin. And in 1999, further studies showed that crocin suppressed the development of colon cancer. These findings could open up a new area of medicinal use for the plant.

2004, Reader's Digest

Nature's Medicines

Why is life expectancy longer for women than it is for men ?

Both biological and social factors affect life expectancy. Biology strikes first : during the 12 months of infancy, male mortality is typically 25 to 30 percent greater than female mortality. Some 105 males are born for every 100 females, ensuring that the number of men and women will be about the same at reproductive age. Hormones also play a role in longevity. The female hormone estrogen helps to eliminate "bad" cholesterol (LDL) and thus may offer some protection against heart disease. In contrast, testosterone, found in greater amounts in males, may make men more likely to engage in violence and risk-taking behavior. The female body's ability to adapt to pregnancy and breast-feeding appears to help women manage excess calories more easily than men do. Finally, women gain an additional biological advantage because of their two X chromosomes. If a gene mutation occurs on one X, women's second X chromosome can compensate. In comparison, all the genes on men's sole X chromosome are expressed, even if they are deleterious.

Male and female life habits have been converging in the industrial world, this convergence is not absolute. Females tend to smoke fewer cigarettes, drink less alcohol and drive more carefully. On average, their professional activities are less prejudicial to their health.

In the past, women's social status and life conditions, such as the hardships associated with childbirth, nullified their biological advantage. (In some countries, this effect continues today. Women lived only 0.1 year longer than men in Bangladesh in the 1990s, and women in India lived 0.6 year longer than men did.) But today, at least in industrial countries, economic and social advances have largely erased status inequalities, and women's life expectancy is longer than that of men. For example, in the 1990s U.S. women lived 6.7 years longer than U.S. men, and women in the U.K. and France lived 5.3 years and 7.8 years longer, respectively, than the men in those countries.

December 2004, Scientific American

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Cheaper AIDS drug

Chinese authorities have for the first time approved the use of a traditional medicine to treat AIDS. The country's State Food and Drug Administration recently licensed the medicine called tangcaopian. The drug increases levels of CD4 immune cells in AIDS patients. This implies that it strengthens their immune response to the HIV virus. Its cost is US $725 per patient every year, which is much less than the US $2,400 expense incurred for the generic AIDS drugs available in Chinese markets at present.

May 31, 2004 Down to Earth

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Arnica

Arnica contains anti-inflammatory sesquiterpenic lactones-the most important medically is helenalin. Arnica also contains flvonoids which strengthen blood vessels.

Arnica's primary use is for relieving bruising. The various lactones found in the plant inhibit the leakage of blood under the skin and prevent the inflammation of the tissues surrounding the area.

Arnica is also used to relieve sprains and other minor injuries where there is swelling but no blood loss or broken skin. In studies carried out in 1979 and 1980 using sesquiterpenic lactones, helenalin was found to inhibit swelling and chronic arthritis in rats.

Another use of arnica is for treating bacterial and fungal infections. It should never be taken internally, although there is a homeopathic form that is a remedy for injuries, accidents and shock.

2004, Reader's Digest

Nature's Medicines

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Hot on the Trail of Cosmic Rays

Researchers are closing in on finding the source of galactic cosmic rays, charged particles that whiz around the galaxy in huge numbers and constantly bombard Earth's upper atmosphere. Images published in Nature show the production of high-energy gamma rays around the remnant of a supernova, knows as RX J1713.7-3946. The pictures, taken with a new gamma ray telescope called the High Energy Spectroscopic System (HESS) in Namibia (Science, 3 September, p. 1393), mark the first time researchers have produced a resolved image of a supernova remnant at such high energies. Astrophysicists believe that these gamma rays, with energies of about 1012 electron volts (TeV), are produced at the same time as cosmic rays and so mark the location of their source, but they haven't got proof yet. "This strong signal is a breakthrough", says Karl Mannheim of the University of Würzburg in Germany. "But there are many open questions".

Cosmic rays travel at speeds produced in the most powerful particle accelerators. Theorists believe that when particles streaming out of a supernova remnant hit interstellar gases, protons and other light nuclei get boosted by the shock wave and produce a few TeV gamma rays as a byproduct. The problem is, electrons streaming from a supernova remnant can also generate TeV gamma rays, without cosmic rays being involved. The HESS team should be able to figure out whether protons or electrons are the culprits by studying the supernova at other wavelengths, such as radio waves, to figure out the density of matter around it. "We're just gearing up that", says HESS spokesperson Werner Hofmann of the Max Planck Institute for Nuclear Physics in Heidelberg.

November 5, 2004 Science

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A Day at the Beach        

Any Sun Worshiper knows the damagingeffects of ultraviolet rays. At the molecular level, much of this damage is in the form of cyclobutane pyrimidine dimers (CPD) in DNA.

Fortunately, DNA photolyases in prokaryotes, plants, and many animals can repair these lesions using blue light as an energy source. Understanding the mechanism of light-driven DNA repair has been hampered by the lack of high resolution structure of UV-damaged DNA bound to photolyase. Now Mees et al. (p. 1789) have determined the structure of Anacystis nidulans photolyase in a complex with duplex DNA containing a CPD-like lesion at 1.8 ? resolution. Apparently synchrotron radiation triggered repair of the CPD so that the structure represents a cryotrapped cleavage intermediate in which the thymine dimer is flipped into the active site of the photolyase. The structure explains much existing biochemical data and provides a basis for future studies of mechanism.

December 3, 2004 Science

Computers Can Make You Blind

Researchers from Tokyo's Toho Medical School have warned that people who spend long hours in front of the computer screens and have existing eye conditions have the risk of developing glaucoma. Glaucoma is a progressive eye disease that can lead to blindness.

This dramatic discovery contradicts years of advice, which suggested that gazing at computers did not damage the optic nerve.

The results emerged from a study in Japan of 10,000 workers with an average age of 43. It found a statistical link between heavy computer use and eye problems that presage glaucoma. The problems were more common among staff with existing vision defects.

The researchers also found a significant statistical link with heavy computer use among myopic workers. They suggested that the optic nerve in myopic people might have a structural condition that renders it more susceptible to computer stress than non-myopic eyes.

December 2004, Digit

More brain for language

A third language area identified in the cortex. A new language area has been identified in the brain following a study conducted by researchers at the Neuroimaging Sciences Institute of Psychiatry, King's College, London.

Named "Geschwind's territory" after the American neurologist who first suggested its existence in the 1960s, this is the third area in the brain to be associated with language. Its presence which revealed through the powerful new brain scanning technique, the diffusion tensor Magnetic Resonance Imaging, according to a study published in Annals of Neurology (Vol 57, No 1).

Till now, the language network of the brain was believed to consist of two areas - Broca's area was associated with the production of language, while Wernicke's area was for comprehension. These two areas are located in the cortex, the outermost layer of the brain.

Broca and Wernicke noted that damage to the cortical areas produced primary language production or language processing disorders but not both. These areas were found to be connected by a large bundle of nerve fibres and damage to this pathway also produced language disorders. 

The "Geschwind's territory" is the last area in the brain to mature, the completion of its maturation coinciding with the development of reading and writing skills.

The future line of the study will be to examine the maturation of this area and its connections in the context of autism (a developmental brain disorder that typically appears during the first three years of life and affects brain areas controlling language, social interaction and abstract thought) and dyslexia (learning disability characterized by reading difficulties).

According to the researchers, these pathways appear to exist in more rudimentary forms in the brains of monkeys. This may have a bearing on the search for the evolutionary origins of language. "These data suggest that language evolved in part from changes in pre-existing networks, not through the appearance of new brain structures," pointed out Catani.

February 15, 2024 Down To Earth

Wheatgrass juice as medicine

Wheatgrass juice is the juice extracted from wheat sprouts. Theory on the healing power of grasses was predicated upon the Biblical story of Babylonian king Nebuchadnezzar who spent seven years, insane, living like a wild animal eating the grass of the fields. Because he recovered it is theorized that the grasses had cured his insanity. The common observation that dogs and cats nibble on grass, presumably when they feel ill, also strengthened the belief in the healing power of grasses. The life span of the wheatgrass juice is less than three hours so it had to be cut from growing plants, juiced and consumed fresh.

The Wheatgrass juice is up to 70% chlorophyll. The chemical composition of chlorophyll is reported to be closely resembles haemoglobin. Chlorophyll is antibacterial and can be used inside and outside the body; it rebuilds the blood stream, gets into the tissues and refines them, improves blood sugar problems, neutralizes toxins in the body, helps purify the liver and wash drug deposits from the body, prevents tooth decay, helps with tooth pain and strengthens the gums.

January-February 2003,

Natural Product Radiance Vol 2(1)

Noseblock!

Ever heard of a fly with a blocked nose? Soon there will be swarms of fruit flies incapable of sniffing their way to their food, because they lack Or83b, the gene that controls the sense of smell in most insects. Scientists are in the process of designing a compound of insect repellents that will block this gene.

February 28, 2024 Down to Earth

Herbal drugs against leprosy

The herbal drugs Chirata, Gulancha Tinospora, Prickly-Chaff Flower, Cutch Tree, Henna and Indian Oleander are known to possess antileprotic properties. Dapsone is an antibiotic effective against the bacteria that cause leprosy. Asthana and others at Department of Pharmaceutical Sciences, Dr. H.S. Gour Vishwavidyalaya, Sagar tested the extracts of these drugs against the pathogens (M. T. B.G37 RV, Mycobacterium fortuitium, M. kansasii, M. phlei and M. smagmetis) having characteristics common to Mycobacterium leprae. They observed that only three drugs S. chirayita, T. cordifolia and A. aspera showed broth activities.

Chirata was found to be superior in activity than other two drugs. The inter- combinations have given better results than any one of the drugs alone. Dapsone in combination with these drugs has shown improved antileprotic activity.

March-April 2002,

Natural Product Radiance

Edited by Dr. A. M. Mehendale

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