Tag Archives: Imperial College London

Second Time Dengu Attack Spells Danger

Scientists now know why a second dengue infection is much more severe than the first.
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The long-kept secrets of the dengue virus — which affects between 50 and 100 million people every year — are tumbling out.

Scientists have long wondered why a re-infection (in the same or subsequent year) causes more complications, even becoming fatal, than when it strikes the first time. The puzzle has been finally solved — by two independent research teams. The knowledge gained by the scientists is expected to help design drugs and vaccines against dengue fever, which currently has no treatment.

Normally, viruses — which have very little genetic material of their own — co-opt the host’s genetic machinery to survive and replicate. More often than not, if the host has an efficient immune system, the invaders are destroyed. In most cases, the antibodies produced by the body stay for long, if not permanently, and fight off any subsequent attack by the same virus. But in the case of dengue, the second infection proves to be much more severe than the first.

Back in the 1970s, US virologist Scott Halstead hypothesised that the dengue virus may be receiving help from the very antibodies that are supposed to fight the infection. Halstead termed the phenomenon antibody-dependent enhancement (ADE) of infection. He got an inkling of this during his extensive clinical studies in Thailand in the 1960s.

For a good part of the ensuing four decades, Halstead’s assumption remained mere theory. But in February this year, Sujan Shresta, a Nepal-born virologist at the La Jolla Institute of Allergy and Immunology in California, came up with conclusive proof for Halstead’s hypothesis. “It’s a situation where antibodies can be bad for you — it’s counter to everything we know about the normal function of antibodies,” she says.

Dengue infection is transmitted by the Aedes aegypti mosquito. There are four known strains of the virus circulating in the world. Infection can cause diseases ranging from dengue fever, a flu-like illness, to the severest form — dengue haemorrhagic fever or dengue shock syndrome. The latter can cause the blood vessels to leak, leading to life-threatening shock. It is estimated that 2.5 billion people — that is, two-fifth of the world’s population — live in regions where dengue fever is rampant. While it is more common in South East Asia and South America, the incidence is rising in India too. Since 1996, the country had witnessed a number of dengue outbreaks and a few hundred Indians die of dengue-related complications every year.

Shresta’s team at La Jolla developed the first ever mouse model to study the disease. The scientists conducted experiments to prove that certain antibodies produced by the body against the virus indeed exacerbate the condition. The four strains of the virus circulate simultaneously, says Shresta. Infection with one provides lifelong immunity against that particular strain. In subsequent infections, where a different strain of the virus is involved, the antibodies do not recognise enough of the virus to neutralise it. “This starts a cascade of unusual molecular events — the ADE process — which leads to the antibodies contributing to, rather than fighting, the infection,” she explains.

Taking the research forward, a team of UK and Thai scientists identified specific antibodies involved in the ADE process. The study, reported early this month in the journal Science, showed that the culprits are antibodies against a particular viral protein called precursor membrane protein (prM). According to the researchers, if the antibodies are present in the body, the infection spreads faster with the antibodies against prM helping the virus infect more host cells. In fact, there is a several hundred-fold increase in the number of infected cells in the presence of the antibodies, they say.

“This is a significant piece of work. It shows the exact region for the enhancement — which is the prM, and not the E region of the virus, as we have been thinking so long,” says Shamala Devi Sekaran, a virologist at the University of Malaysia who has been studying the dengue virus for years.

“The study pinpoints the nature of the antibodies that are likely to cause the severest form of the disease in humans,” says Shresta. It will greatly help those trying to develop vaccines against dengue, she adds.

“Our research gives us some key information about what is not likely to work when trying to combat the virus. We hope our findings will bring scientists one step closer to creating an effective vaccine,” says Gavin Screaton, head of medicine, Imperial College London, and lead author of the study.

The biggest challenge is that the dengue vaccine will need to provide immunity against all the four strains of the virus at the same time. “If protection is incomplete, the vaccine can potentially protect against some viruses but leave the individual primed for a more severe outcome if he or she is infected with the others,” Screaton told Knowhow.

In addition to these developments, there have been two recent breakthroughs in controlling the dengue mosquito. Oxford University scientists developed sterile male Aedes aegypti mosquitoes which have undergone successful semi-field trials in Asia. And scientists at the University of Queensland developed a mutant strain of a bacterium called Wolbachia, which halves the adult life span of female Aedes aegypti mosquitoes in laboratory conditions.


Source:
The Teleghraph ( Kolkata, India)

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Beat The Bugs

Swine flu cases may have been steadily decreasing over the summer – but experts are expecting a surge in new cases in the next few months.
……..CLICK & SEE
The main reason is that cooler weather means more of us group together indoors and so are more likely to pass on viruses to one another.

Once released into the air via coughs and sneezes, some viruses can live for several hours on surfaces such as tables, doorknobs and desks, which is why keeping hands clean is so important.

Antibacterial washes and wipes will kill some viruses and are great for protecting surfaces against potential sources of tummy bugs.

According to Professor Wendy Barclay, chair of Influenza Virology at Imperial College London, there are some basic steps people can take to protect themselves from swine flu and other seasonal flu, coughs and colds.

Top tips for preventing swine flu:-
*KEEP YOUR HANDS CLEAN: Wash them thoroughly and frequently – especially before eating or preparing food – and rinse under clean running water to remove any infected mucous.

*DRY YOUR HANDS AFTER WASHING: Wet hands are more likely to pick up and spread germs.

*KEEP HANDS AWAY FROM THE FACE: If someone sneezes and then opens a door, the next person to touch the handle will come into direct contact with the virus. So, do not touch your eyes, nose or mouth until you’ve washed your hands.

*SNEEZE INTO A TISSUE- THEN BIN IT: Cover your mouth and nose when you sneeze and then dispose of the tissue carefully. Don’t leave it hanging around or re-use it several times.

AVOID OVER-USE OF HAND GELS: Don’t rush out and buy dozens of hand gels to use on the move. They’re useful in situations where there are no washrooms. But if you have access to soap and water at the end of a journey, use that as it is just as effective.

KEEP SURFACES CLEAN: Proprietary sprays are fine, but a mild solution of washing-up liquid and water works equally well.
OPEN A WINDOW: Humidifiers and air purifiers may be effective, but they are still not fully tested against the swine flu virus. One of the most efficient ways to clear the air and dilute the virus is simply to open a window.
LOOK AFTER YOURSELF: The body’s own immune system offers the best protection from illness. Eating a good and varied diet, drinking plenty of water and taking regular exercise are the best ways to stay healthy and avoid getting the disease in the first place. Plus, if you or your family do succumb to swine flu, being in good health will help everyone to shrug it off quickly and without complications.

GADGET UPDATE
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Source: mail Online 20th. Sept. 2009

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Jicama (Pachyrrhizus erosus)

Botanical Name:Pachyrrhizus erosus
Familia: Fabaceae
Subfamily: Faboideae
Division: Magnoliophyta
Pinduan: Magnoliopsida
Orden: Fabales
Genus: Pachyrhizus
Species: P. erosus

Also known as:
Mexican turnip, Mexican yam bean, potato bean , yam bean
Other names for this Asian vegetable…
China:  dou shu, dou su, sha ge, di gwa, fan ko, lian shu, sa got, sha kot
India:  sankalu (In Bengali :Sankalu)
Indonesia:  bangkoe wang, beng kooway, bengko wang, benkuan, besusu, huwihiris, seng kooang
Japan:  kuzu imo
Laos:  man pau
Malaysia:  beng kuwong, kacang sengkuang, sengkwang, singkong, ubi sengkuang
Philippines:  bunga, frijolnme, kamas, singkamas, sinkamas
Sri Lanka:  yam bean
Thailand:  hua pae kkua, man kaeo, man laao, manngaw
Vietnam:  cu dau, cu san.

Common Names: Jicama, Mexican Potato, Yam Bean Jicama (pronounced “hecama”) is also known as yam bean and Mexican turnip. It is not related to the true yam. The name “jicama” is almost always used in Spanish for any edible root. It is a climbing legume with very long and large tuberous roots, which in 5 months of growth may reach 6-8 feet long and weigh 50 pounds or more. More often, roots are round and beet-shaped with a distinctive taproot.

It is known as Sankalu  in Bengal

Habitat:Native in Maxico. but now grows in most of Asiatic countries and many  other places of the world.

Description:
It is a crepary annual plant. mainly grown in tropical countries.The plant grown from square brownish seedsIt takes 5 to 9 months to for it’s root (tubers) to be readfy to harvest. If left un harvested  the tubes can grow 6 feet long and may weigh 50 pounds even.

Click to see

Fruit on the root

Above the ground the plant grows as a broad -leafed vine of about 20 to 30 ft. long. depending on variety.It blossoms with light purple or white flowers which will produce fuzzy beans. The flowers are often removed to make larger tuber.

Also known as yam bean, this crunchy white fleshed tuber is a popular substitute for water chestnuts or bamboo shoots in any dish that calls for a mild flavor and crisp texture. The heart-shaped tuber grows to about 6″x6″ and has light brown skin. Jicama needs a lot of heat and a long growing season. Tubers develop after flowering. Ripe pods and leaves are poisonous. Jicama, which stores very well, is delicious in a marinated salad or stir-fry

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Growing Info:
Jicama is a tropical plant and thus requires at least 9 months of warm growing season for good sized roots to mature. However, if soil is rich, light and there is at least 4 months of warm weather available, the resulting roots will be smaller, but still quite delicious.
– Presoak seeds in water for about 24 hours before planting. Can be started indoors about 8 to 10 weeks before the last spring frost.
– Transplant into your garden as soon is weather is warm, but be careful where you plant it as the ripe pods, leaves and seeds are toxic and narcotic. Care should be taken so that no humans or animals will mistakenly eat these parts.
– The immature seed pods are edible as well as of course the turnip like roots for which it is grown. Can be grown near a trellis for support or like pole beans. Can also be grown on the ground but then requires a lot of space.
– When they grow to about 3 feet tall, pinch the tips to promote horizontal branches. Tubers form as the days grow shorter and should be harvested before the first frost.
– If you allow the plants to go to seed, the root lobes will be small. Blossoms appear in late summer, but can be pinched out for maximum root growth.

Uses:
This is an unusual vegetable that is becoming increasingly popular with American cooks, but has been grown in its native Mexico for centuries. More and more U.S. supermarkets are now carrying this turnip shaped, usually four lobed root. Its skin is a brownish gray, but its flesh is white and crisp. It’s flavor resembles that of water chestnuts but is sweeter. Makes a great appetizer and is a very good addition in both taste and texture when added to salads.

Jicamas are actually perennials and produce their large roots after several years of growth. They are commonly found in frost free regions. In Texas, seed can be planted in the early spring and small tubers harvested before the first killing frost of the winter.

Culinary Uses

Jicama is most commonly eaten in the fresh form. After peeling to remove the brown fibrous outer tissue, the crisp white fleshy portion can be sliced, diced, or cut into strips for use as a garnish, in salads, or with dips. It is frequently served as a snack sprinkled with lime or lemon juice and a dash of chili powder. Jicama remains crisp after boiling and serves as a textural substitute for water chestnuts. Jicama is similar to white potatoes in food value, but with slightly lower total food energy (calories). In the tropical production areas, the immature pods are sometimes cooked and eaten, but mature pods are said to be toxic. Mature seeds contain a fairly high content of rotenone, and at one time, commercial culture of jicama was considered as a source of this insecticide.

Health benefits of Jicama:

*Jicama is one of the very low calorie root vegetables; carrying only 35 calories per 100 g. However, its high quality phyto-nutrition profile comprises of dietary fiber, and anti-oxidants, in addition to small proportions of minerals, and vitamins.

*It is one of the finest sources of dietary fiber; particularly excellent source of oligofructose inulin, a soluble dietary fiber. The root pulp provides 4.9 mg or 13% of fiber. Inulin is a zero calorie sweet inert carbohydrate. It does not metabolize inside the human body, which make the root an ideal sweet snack for diabetics and dieters.

*As in turnips, fresh yam bean tubers are also rich in vitamin C; provide about 20.2 mg or 34% of DRA of vitamin C per 100 g. Vitamin-C is a powerful water-soluble anti-oxidant that helps body scavenge harmful free radicals, thereby offers protection from cancers, inflammation and viral cough and cold.

*It also contains small levels of some of valuable B-complex group of vitamins such as folates, riboflavin, pyridoxine, pantothenic acid and thiamin.

*Further, the root provides healthy amounts of some important minerals like magnesium, copper, iron and manganese.

Click & see :What Is Jicama (Yambean) Good For?

Click to see nutritional value of Jicama :

Availability: Jicamas are offered in Texas supermarkets but are more popular in deep South Texas. Most of those on the market are imported from Mexico and South America

Resources:
http://electrocomm.tripod.com/jicama.html
http://www.practicallyedible.com/edible.nsf/pages/jicama
http://pam.wikipedia.org/wiki/Singkamas
http://www.kitazawaseed.com/seed_222-43.html

http://cgi.ebay.com.my/ws/eBayISAPI.dll?ViewItem&item=130303238863

New Way to Repair Heart Attack Damage

Mouse embryonic stem cells with fluorescent ma...

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British scientists have developed a stem cell treatment that could dramatically boost the body’s ability to repair itself. The treatment,  which makes the bone marrow release a flood of stem cells into the bloodstream, could heal serious tissue damage caused by heart attacks and even repair broken bones.

Scientists already use stem cell therapy to treat leukemia patients, getting the marrow to release a type of stem cell that can only make fresh blood cells. British researchers said, “They have found a way to get the bone marrow to release two other types of stem cell that can repair bone, blood vessels and cartilage.”

“The bone marrow of treated mice released 100 times as many stem cells, which help to regenerate tissue”, said Sara Rankin who led the research team at Imperial College. “We hope that by releasing extra stem cells, as we were able to do in mice in our study, we could potentially call up extra numbers of whichever stem cells the body needs, in order to boost its ability to mend itself and accelerate the repair process,” she said.

The group hopes to begin trials later this year to investigate how effective it is at repairing tissue damage in rodents. “All the evidence suggests these cells will make a significant difference to the natural repair process,” Rankin said.

Peter Weissberg, medical director at the British Heart Foundation, which co-funded the research along with the Welcome Trust, said: “It now seems increasingly likely that the bone marrow also contains cells that have the capacity to repair damaged internal organs, such as the heart and blood vessels, but that too few of them are released to be effective.”

He further added, “This research has identified some important molecular pathways involved in mobilizing these cells. It may be possible to develop a drug that interacts with these pathways to encourage the right number and type of stem cells to enter the circulation and repair damage to the heart.”

Sources:
The Times Of India

Stem Cell Therapy May End Transplants

myocardial infarction - Myokardinfarkt - scheme
Image via Wikipedia

British scientists have developed a new technique that can rebuild a severely damaged heart, and one day, might replace the need for transplantation.

Researchers at Imperial College London revealed that stem cell heart surgery can help repair damaged hearts using progenitor cells derived from patients’ own cardiac muscle.

They have discovered a way to extract, grow in the laboratory and then graft on a patient’s own muscle-building cells which then can be used to patch up the heart and increase its pumping power. Moreover, it can increase the quality of life for people who suffer a heart attack.

“This could transform the care for patients who have had heart attacks or have heart disease,” the Telegraph quoted Nicholas Boon, president of the British Cardiovascular Society as saying. “Because the cell therapy uses a patient’s own cells, it negates the risks or complications associated with other treatment options such as rejection linked to transplantation,” he said

Sources: The Times Of India

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